15435	----	Note: Project Gutenberg also has an HTML version of this file which includes the original illustrations. See 15435-h.htm or 15435-h.zip: (http://www.gutenberg.net/dirs/1/5/4/3/15435/15435-h/15435-h.htm) or (http://www.gutenberg.net/dirs/1/5/4/3/15435/15435-h.zip) Practical Work in the School Room Series. Part I OBJECT LESSONS ON THE HUMAN BODY A Transcript of Lessons Given in the Primary Department of School No. 49, New York City Pupils' Edition (Revised) New York: Parker P. Simmons, Successor to A. Lovell & Company 1904 AUTHOR'S NOTE TO THE PUPIL This book has been prepared to help you in learning about "the house you live in," and to teach you to take care of it, and keep it from being destroyed by two of its greatest enemies,--Alcohol and Nicotine. As you study its pages, be sure to find out the meaning of every word in them which you do not understand; for, if you let your tongue say what your mind knows nothing about, you are talking _parrot-fashion_. And do not forget that you must pay for all the knowledge you obtain, whether you are rich or poor. Nobody else can pay for you. You, your own self, must _pay attention_ with your own mind, through your own eyes and ears, _or do without knowledge_. Be wise: gain all the knowledge you can concerning everything worth knowing, and use it for the good of yourself and other people. "KNOWLEDGE IS POWER." [Illustration: A, the heart; B, the lungs; light cross lines, arteries; heavy lines, veins.] PART I. FORMULA FOR INTRODUCTORY LESSONS. 1. My body is built of bones covered with flesh and skin; the blood flows through it, all the time, from my heart. I breathe through my nose and mouth, and take the air into my lungs. 2. The parts of my body are the head, the trunk, the limbs. 3. My head. The crown of my head. The back of my head. The sides of my head. My face. My forehead. My two temples. My two eyes. My nose. My two cheeks. My mouth. My chin. My two ears. My neck. My two shoulders. My two arms. My two hands. My trunk. My back. My two sides. My chest. My two legs. My two knees. My two feet. I am sitting erect. * * * * * QUESTIONS FOR THE FORMULA. 1. Tell about your body. 2. Name the parts of the body. 3. Name the parts of the head, trunk, and limbs. * * * * * THE NOSE AND THE MOUTH. Be sure to keep your mouth closed when you are not talking or singing, especially when you are walking, running, or _asleep_. The two nostrils are outside doors, always open to admit the air, and inside of the upper part of the nose there are two other openings, through which it passes into the throat. Air which goes this way is warmed, cleansed, and moistened, but that which is breathed directly through the mouth is not so well prepared for its work in the lungs. Do not use your mouth as a box or a pin-cushion; the pin, or whatever yon have put into it, may slip into your throat and cause your death. * * * * * QUESTIONS ON THE INTRODUCTORY LESSONS. Of what is the body built?--"Of bones." What covers the bones?--"Flesh." What covers the flesh?--"Skin." What flows through the body?--"Blood." Where does the blood flow from?--"The heart." When does the blood flow from the heart?--"Every time the heart beats." Show with your hand how the heart beats. When does the heart beat?--"All the time." What happens when the heart stops beating?--"We die." What do you see on the back of your hand, beneath the skin?--"Veins" What is in the veins?--"Bad blood." What are the veins?--"Pipes for the bad blood to pass through." Where do the veins carry the bad blood?--"To the heart." Where does the heart send the bad blood?--"To the lungs." What happens to the bad blood when in the lungs?--"It is made pure." What makes the bad blood pure?--"The air." How does the air get into the lungs?--"Through my nose, mouth, and windpipe." What is breathing?--"Letting the air into and out of my lungs, through my nose, mouth, and windpipe." When do you breathe?--"All the time." What do you breathe?--"Air." What do you breaths through?--"My nose, mouth, and windpipe." Where do you get the air?--"Everywhere." Where do the lungs send the pure blood?--"To the heart." Where does the heart send the pure blood?--"All through the body." How does the heart send the pure blood through the body?--"Through pipes called arteries." What kind of blood passes through the arteries?--"Pure blood." What kind of blood passes through the veins?--"Impure blood." What carries the pure blood through the body?--"The arteries." What carries the impure blood through the body?--"The veins." What makes blood?--"Food and drink." What is food?--"Anything good to eat." What is drink?--"Anything good to drink." Name some kinds of wholesome food.--"Meat, potatoes, oranges, apples, etc." Name some kinds of wholesome drink.--"Water, milk, lemonade, etc." What do you mean by wholesome food?--"Food that will make good blood." What do you mean by wholesome drink?--"Drink that will make good blood." What does the blood make?--"Bones, flesh, skin, hair, nails, and cartilage." What use is the blood to the body?--"It makes the body grow, and keeps it alive." Name some kinds of poisonous drinks.--"Rum, brandy, ale, cider, etc." What do you mean by poisonous drinks?--"Drinks which hurt or poison the body." Why do you say that rum and the other drinks you have named are poisonous?--"Because they do harm to every part of the body." Which part do they hurt most?--"The head or brain." What harm do they do to the brain?--"They make it unfit to do its work." What work does the brain do?--"Thinking." Then what harm do rum, brandy, wine, and these other drinks do to the brain?--"They make it unfit to think." What other poison do some people use?--"Tobacco." When do children use tobacco?--"When they chew tobacco; when they smoke cigars or cigarettes." How much does tobacco poison hurt children?--"More than it hurts anybody else." In what way does it hurt children?--"It keeps children from growing fast; from being strong and healthy; and from learning as well as they ought." How does it do all this mischief to children?--"It poisons their lungs, their heart and blood, and their brain." * * * * * PART II. FORMULA FOR THE PARTS AND JOINTS OF THE BODY: 1. My limbs are my two arms and my two legs. 2. My arm has two parts: my upper arm, my fore-arm; and three joints: my shoulder joint, my elbow joint, my wrist joint. 3. My hand is used in holding, throwing, catching, and feeling: the palm of my hand, the back of my hand, my fingers, my thumb, my forefinger, my middle finger, my ring finger, my little finger, my knuckles, my finger joints, my nails, the tips of my fingers, the veins, the ball of my thumb, and the lines where the flesh is bent. 4. My leg has two parts: my thigh, and my lower leg; and three joints: my hip joint, my knee joint, my ankle joint. 5. My foot is used in standing, walking, running, skating, and jumping: my instep, my toes, the sole of my foot, the ball, the hollow, the heel, my toe joints, and my toe nails, which protect my toes. * * * * * QUESTIONS FOR THE FORMULA. 1. Which are your limbs? 2. Tell about your arm. 3. Tell about your hand. 4. Tell about your leg. 5. Tell about your foot. * * * * * [Illustration: THE ELBOW JOINT. (A hinge joint.)] [Illustration: THE HIP JOINT. (A ball-and-socket joint.)] Some joints, as those of the skull, are immovable; some, as those of the spine, may be moved a little; and others more or less freely, as those of the limbs. In machines, the parts which move upon each other need to be oiled, to keep them from wearing out; but the joints of our bodies oil themselves with a thin fluid, called _synovia_. This fluid resembles the white of an egg, and comes from a smooth lining inside of the joints. The ends of the bones which form joints are covered by gristle or _cartilage_, and are fastened together by very strong, silvery white bands, called _ligaments_. A sprain is caused by overstretching or tearing some of these ligaments. * * * * * QUESTIONS ON THE LIMBS AND JOINTS OF THE BODY. What is the trunk of your body?--"All the body but the head and limbs." Which are your limbs?--"My two arms and my two legs." How many limbs have you?--"Four." How many parts has your arm?--"Two parts: my upper arm and my fore-arm." How many parts has your leg?--"Two parts: my thigh and my lower leg." How many joints has your arm?--"Three joints: my shoulder joint, my elbow joint, my wrist joint." How many joints has your leg?--"Three joints: my hip joint, my knee joint, my ankle joint." What are joints?--"Bending places." How many kinds of joints have you?--"Two: hinge joints, and ball-and-socket joints." What kind of a joint is the shoulder joint?--"A ball-and-socket joint." Why do you call the shoulder joint a ball-and-socket joint?--"Because at the shoulder the arm may move in any direction." Tell how the shoulder joint is made.--"The upper end of the bone of the upper arm is rounded and fastened in a hollow place called a socket." Which of the joints of the arm and hand are hinge joints?--"The elbow joint, the wrist joint, the thumb joint, the finger joints." Which of the joints of the leg and foot are hinge joints?--"The knee joint, the ankle joint, the toe joint." Which of the joints of the leg is a ball-and-socket joint?--"The hip joint." Where is the heel?--"At the back part of the foot." Where is the ball of the foot?--"On the sole of the foot, behind the great toe." Where is the hollow of the foot?--"In the middle of the sole of the foot." Where is the sole of the foot?--"On the bottom of the foot." Where is the instep?--"Between the ankle joint and the toes." Where is the lower leg?--"Between the knee joint and the ankle joint." Where is the thigh?--"Between the hip joint and the knee joint." Where is the upper arm?--"Between the shoulder joint and the elbow joint." Where is the fore-arm?--"Between the elbow joint and the wrist joint." Where are the toe joints?--"Between the parts of the toes." Where are the finger joints?--"Between the parts of the fingers." Where is the ankle joint?--"Between the lower leg and the foot." Where is the knee joint?--"Between the thigh and the lower leg." Where is the hip joint?--"Between the trunk and the thigh." Where is the wrist joint?--"Between the fore-arm and the hand." Where is the elbow joint?--"Between the upper arm and the fore-arm." Where is the shoulder joint?--"Between the trunk and the upper arm." Where are the tips of the fingers?--"At the ends of the fingers." Where is the ball of the thumb?--"On the palm of the hand, below the thumb." Where is the palm of the hand?--"On the inside of the hand, between the wrist and fingers." * * * * * [Illustration: THE SKELETON.] 1. The skull. 2. The spine. 3. The ribs. 4. The breastbone. 5. The shoulder blades. 6. The collar bones. 7. The bone of the upper arm. 8. The bones of the forearm. 9. The bones of the wrist. 10. The bones of the fingers. 11. The bones of the thigh. 12. The bones of the lower leg. 13. The bones of the ankle. 14. The bones of the toes. 15. The kneepan. 1. The skull. 2. The spine. 3. The ribs. 4. The breastbone. 5. The shoulder blades. 6. The collar bones. 7. The bone of the upper arm. 8. The bones of the forearm. 9. The bones of the wrist. 10. The bones of the fingers. 11. The bones of the thigh. 12. The bones of the lower leg. 13. The bones of the ankle. 14. The bones of the toes. 15. The kneepan. * * * * * PART III. FORMULA FOR THE LESSON ON THE BONES OF THE BODY. 1. My bones are hard; they make my body strong. There are about two hundred bones in my body. 2. The bones of my head are my skull and my lower jaw; my face has fourteen bones; my ear has four small bones; at the root of my tongue is one bone. 3. The bones of my trunk are my spine, my ribs, my breastbone, my two shoulder blades, and my two collar bones. 4. My upper arm has one bone; my fore-arm has two bones; my wrist has eight bones; from my wrist to my knuckles are five bones; my thumb has two bones; each finger has three bones, making nineteen bones in my hand. 5. My thigh has one bone; my lower leg has two bones; my knee-pan is the cap which covers and protects my knee; in my foot, near my heel, are seven bones; in the middle of my foot are five bones; my great toe has two bones; each of my other toes has three bones; making twenty-six bones in my foot. * * * * * QUESTIONS FOR THE FORMULA. 1. Tell about your bones. 2. Tell about the bones of the head. 3. Tell about the bones of the trunk. 4. Tell about the bones of the arm and hand, beginning with the upper arm. 5. Count the bones of the hand. 6. Tell about the bones of the leg and foot, beginning with the thigh. * * * * * [Illustration: FIG. A. 1, 2, 3, 4, the upper row of the bones of the wrist. 5, 6, 7, 8, the lower row of the bones of the wrist. 9, 10, the lower ends of the bones of the fore-arm. 11, 12, 13, 14, 15, the upper ends of the bones of the palm of the hand. The bones of the wrist are so firmly fastened together that they are seldom put out of place. The upper row joins with the bones of the fore-arm, the lower with those of the palm of the hand.] [Illustration: FIG. B. 1, 2, 3, 4, 5, the bones of the palm of the hand. 6, 7, the bones of the thumb. 8, 9, 10, the bones of the first or fore-finger. 11, 12, 13, the bones of the second or middle finger. 14, 15, 16, the bones of the third or ring finger. 17, 18, 19, the bones of the fourth or little finger.] * * * * * QUESTIONS ON THE BONES. How many bones in the body?--"About two hundred." Of what use are the bones to the body?--"They make the body strong; they form the framework of the body." How many bones in the face?--"Fourteen." How many bones in the ear?--"Four small bones." How many bones at the root of the tongue?--"One." How many bones in the upper arm?--"One." How many bones in the fore-arm?--"Two." How many bones between the wrist and the knuckles?--"Five." How many bones in the thumb?--"Two." How many bones in each of the fingers?--"Three." How many bones in the whole hand?--"Nineteen." How many bones in the hand and arm?--"Thirty." How many bones in the thigh?--"One long bone." How many bones in the lower leg?--"Two." How many bones in the heel?--"Seven." How many bones in the middle of the foot?--"Five." How many bones in the great toe?--"Two." How many bones in each of the other toes?--"Three." How many bones in the whole foot?--"Twenty-six." How many bones in the foot and leg?--"Thirty." How many bones in two arms and two hands?--"Sixty." How many bones in two legs and two feet?--"Sixty." How many bones in the limbs?--"One hundred and twenty." Where is the knee-pan?--"Over the knee joint." Where is the longest bone of the body?--"In the thigh." Where are the smallest bones of the body?--"In the ear." Point to the collar bones. Point to the shoulder blades. How many collar bones have you?--"Two." How many shoulder blades have you?--"Two." Point to the spine. Point to the breastbone. Point to the skull. * * * * * EXERCISE FOR COUNTING THE BONES OF THE HAND. FOR PRIMARY CLASSES. I. 1. Close both hands. 2. Raise the forefinger of the right hand, as the index or pointing finger. 3. Place the index finger upon the lower thumb joint of the left hand. 4. Draw the index finger down to the wrist, over the bone between the thumb knuckle and the wrist, and count "One." 5. Place the index finger on the knuckle of the first finger. 6. Draw the index finger down to the wrist, over the bone leading from the first finger to the wrist, and count "Two." 7. So on, for each of the three other bones of the hand. Repeat until no mistake is made in touching or counting. II. 1. Raise the thumb, and place the index finger of the right hand on the middle of the upper part of the thumb for bone "Six"; then 2. On the lower part of the thumb for bone "Seven." Repeat from the beginning, until the children can touch and count each bone properly. III. 1. Keep the thumb erect; raise the first finger of the left hand. 2. Place the index finger on the bone between the tip and the first joint of the first finger for bone "Eight." 3. Between the first and middle joint for bone "Nine." 4. Between the middle and third joint for bone "Ten." Review, from the beginning, until the class can touch and count every bone as directed. IV. 1. Keep the thumb and forefinger erect; raise the second finger and touch, as in the lesson on the first finger bones, "Eleven," "Twelve," and "Thirteen." Review. 2. Proceed in the same manner for the third and fourth fingers, always beginning with the bone nearest the tip of the finger, and touching that at the lowest part last. If the exercise has been properly performed, every child will say "Nineteen" as its index finger touches the lowest bone of the little finger, and all the fingers of every left hand will be outspread. * * * * * THE BONES OF THE HEAD: Skull 8 Face, including the lower jaw 14 Tongue 1 Ears 8 ---- 31 OF THE TRUNK: Spine 24 Ribs 24 Breastbone 8 Shoulder blades 2 Collar bones 2 ---- 60 OF THE UPPER LIMBS: Upper arms 1 x 2 = 2 Fore-arms 2 x 2 = 4 Wrists 8 x 2 = 16 Hands 19 x 2 = 38 ---- 60 OF THE LOWER LIMBS: Thighs 1 x 2 = 2 Knee-pans 1 x 2 = 2 Lower legs 2 x 2 = 4 Feet 26 x 2 = 52 ---- 60 Total, 211, not including the teeth.[1] We teach the children to say "about two hundred," because there is not always the same number of bones in the body. In some parts two or three bones unite and form one bone. For example: the breastbone of a child is made up of eight pieces; some of these unite as it becomes older, so that when fully grown it has but three pieces in this bone. [1] The teeth are not bone, but a kind of soft, bone-like substance, called _dentine_. Common ivory is dentine. * * * * * PART IV. FORMULAS FOR THE LESSONS ON THE ORGANS OF SENSE. 1. _The Eyes._--My eyes are to see with. My eye is like a ball in a deep, bony socket. The black circle in the centre is the pupil or window of my eye; the colored ring is the iris or curtain; the white part is the eyeball. My upper and lower eyelids cover and protect my eyes. My eyebrows are for beauty, and keep the perspiration from rolling into my eyes. My eyes are washed by teardrops every time I wink my eyelids. 2. _The Ears._--My ears are to hear with: the rim of my ear, the flap of my ear, the drum of my ear. The drum of my ear is protected by a fence of short, stiff hairs, and by a bitter wax about the roots of these hairs. 3. _The Nose._--My nose is to smell and breathe with; it is in the middle of my face: my two nostrils, the bridge of my nose, the cartilage, the tip of my nose. My nostrils lead to a passage back of my mouth through which I breathe. The cartilage separates my nose into two parts. 4. _The Mouth._--My mouth is to speak, eat, and breathe through: my upper lip, my lower lip. In my mouth are: my tongue, my lower teeth, my upper teeth, my lower teeth, and my upper and lower jaws, covered with flesh called _gum_. 5. _The Teeth._--My teeth are used in eating and talking. My teeth are made of a soft kind of bone, covered with enamel. I have three kinds of teeth: cutting teeth, tearing teeth, grinding teeth. A young child has twenty teeth, ten in each jaw. A grown person has thirty-two teeth, sixteen in each jaw. 6. To preserve my teeth: I must keep them clean. I must not scratch the enamel. I must not eat or drink anything very hot or very cold. I must not use them for scissors or nut-crackers. I must not burn them with tobacco or cigars. 7. _About Eating._--When I eat I move my lower jaw only. My tongue brings the food between my teeth, the cutters cut it, the tearers tear it, the grinders grind it, the saliva moistens it, and my tongue helps me to swallow it. * * * * * QUESTIONS FOR THE FORMULAS. 1. Tell about your eyes. 2. Tell about your ears. 3. Tell about your nose. 4. Tell about your mouth. 5. Tell about your teeth. 6. What is necessary if you would preserve your teeth? 7. Tell about eating. * * * * * [Illustration 1, the muscle which raises the upper eyelid. 2, the upper oblique muscle. 7, the lower oblique muscle. The oblique muscles roll the eye inward and downward. 4, 5, 6, three of the _four_ straight muscles. Two of the straight muscles roll the eye up and down; the other two move it right and left. 3, the pulley through which the upper oblique muscle plays.] * * * * * QUESTIONS ON THE DESCRIPTION OF THE EYES. Of what shape is the eye?--"It is round like a ball." In what is it placed?--"In a deep, bony socket." What is a socket?--"A hollow place." Why is the eye placed in a deep, bony socket?--"To keep it from getting hurt." Why would not an eye shaped like a cube do for us?--"It would not look well; it could not be rolled about." Why would not an eye shaped like a cone or cylinder do for us?--"It could not be rolled in every direction." Why is the ball-shape best for the eye?--"It looks best, and may be rolled in every direction." What part of the eye do we see through?--"The black spot in the centre." What is it called?--"The pupil." What shape is the pupil?--"Round like a circle." What color is the pupil?--"Black." Of what use is the pupil?--"To let light into the eye; to see through." What is around the pupil?--"A colored ring." What is the colored ring called?--"The iris." Of what use is the iris?--"It acts like a curtain to the eye; it lets in and keeps out light from the pupil." Of what shape is the iris?--"Round like a ring." Of what color is the iris?--"Sometimes blue, sometimes brown, sometimes gray." Does the iris always appear the same in size?--"It does not: sometimes it looks large, sometimes small." When is it the largest?--"When it rolls over the pupil to keep out the strong light." When is it the smallest?--"When it rolls backward, to let light into the pupil." When is the pupil the largest?--"When we are in the dark." When is the pupil the smallest?--"When we are in a bright light." What color is the eyeball?--"White." What shape is the eyeball?--"Round like a ball." How is the eyeball held in its socket?--"By cords made of flesh." Where are the eyebrows?--"Above the eyelids." Of what use are the eyebrows?--"To keep the perspiration from rolling into the eyes." Where are the eyelids?--"Over the eyes." Of what use are they?--"They cover the eyes and keep them from getting hurt." Where are the eyelashes?--"On the edges of the eyelids." Of what use are the tears?--"They keep the eyes clean; they make the eyes move easily in their sockets." Where are the tears made?--"Back of the eyebrows." When do the tears wash the eyes?--"Every time we wink our eyelids." * * * * * QUESTIONS ON THE EARS. Name the parts of the ear. Where are your ears?--"On the sides of my head." Which is the rim of the ear?--"The edge of the ear." Which is the flap of the ear?--"The lower part of the ear." Where is the drum of the ear?--"Inside of the ear." How is the drum protected?--"By stiff hairs and a bitter wax at its entrance." * * * * * QUESTIONS ON THE NOSE. Where is the nose?--"In the middle of the face." Name the parts of the nose. Where is the tip of the nose?--"At the end of the nose." Where is the bridge of the nose?--"At the top of the nose, between the eyes." Where is the cartilage?--"In the middle of the inside of the nose." Of what use is the nose?--"To smell and breathe through." What are the nostrils?--"The openings inside of the nose." Of what use are the nostrils?--"To let the air into and out of the opening back of the mouth." * * * * * QUESTIONS ON THE MOUTH, ETC. Where is the mouth?--"In the lower part of the face, between the nose and the chin." Of what use is the mouth?--"To breathe, speak, and eat through." What is in the mouth?--"My tongue, my upper teeth, my lower teeth, and my upper and lower jaws." What covers the jaws?--"Red flesh, called _gum_." Of what are the jaws composed?--"Of bones." Of what are the teeth made?--"Of dentine, covered with enamel." See note, p. 19. What is enamel?--"A smooth, white substance, harder than bone." Of what use are the teeth?--"To eat and talk with." What kinds of teeth have you?--"Cutting teeth, tearing teeth, grinding teeth." Describe the cutting teeth.--"The cutting teeth have broad and flat edges." Describe the tearing teeth.--"The tearing teeth are sharp and pointed." Describe the grinding teeth.--"The grinding teeth are the thick, back teeth." Which jaw is moved in eating?--"The lower jaw." What work do the teeth perform?--"They cut, tear, and grind the food." How many teeth has a child in a full set?--"Twenty teeth: ten in each jaw." How many teeth has a grown person in a full set?--"Thirty-two: sixteen in each jaw." What does the tongue do in eating?--"It rolls the food between the teeth, and helps in swallowing." What is the saliva?--"A kind of liquid, sometimes called _spit_." Of what use is it in eating?--"It wets and softens the food." What do you mean by preserve?--"To keep from injury." What do you mean by injury?--"Hurt." How do you preserve your teeth? See Formula. How do very hot or very cold drinks hurt the teeth?--"They crack the enamel." What happens if the enamel is cracked?--"The teeth decay." Then what must you do to preserve your teeth?--"I must try to keep the enamel from being cracked or injured in any way." * * * * * PART V. FORMULA FOR DESCRIPTION OF THE BONES. 1. My skull is formed of several bones united, like two saws with their toothed edges hooked into each other. 2. My spine extends from the base of the skull behind, down the middle of my back. It is composed of twenty-four short bones, piled one upon the other, with cartilage between them. These bones are fastened together, forming an upright and flexible column, which makes me erect and graceful. 3. My ribs are curved, strong, and light; there are twenty-four of them, twelve on each side; they are fastened at the back to my spine, in front to my breastbone, forming a hollow place for my heart, lungs, and stomach. 4. My shoulder blades are flat, thin, and like a triangle in shape; they are for my arms to rest upon. 5. My collar bones are fastened to my shoulder blades and my breastbone; they keep my arms from sliding too far forward. 6. The bones of old people are hard and brittle; those of children soft and flexible; so I must sit and stand erect, that mine may not be bent out of shape. I must not wear tight clothing, or do anything that will crowd them out of their places. 7. My bones are made from my food, after it has been changed into blood; so I must be careful to eat good, wholesome food, that they may be strong and healthy. 8. I must not breathe impure air, because impure air makes bad blood, and bad blood makes poor bones. 9. The body of every person is changing all the time, because the skin, flesh, and bones are always wearing out, and the blood is always repairing and building them again. * * * * * QUESTIONS FOR THE FORMULA. 1. Tell about the skull. 2. Tell about the spine. 3. Tell about the ribs. 4. Tell about the shoulder blades. 5. Tell about the collar bones. 6. Tell about the difference between the bones of old people and those of children. 7. Of what are your bones made? 8. If you wish your bones to be strong, why should you not breathe impure air? 9. What have you learned about the change which is always taking place in the body? * * * * * [Illustration: THE JOINTS OF THE SKULL.] * * * * * A little girl was looking at some pictures of ladies in fashionable dresses. While admiring the beautiful styles and bright colors of the garments, she pointed to the waist of one, and exclaimed, "_That means trouble_." The waist was too small for a grown person, and could only have been made so by _tight-lacing_. The child had been taught that dresses, corsets, coats, vests, bands, or anything fastened tightly around the waist, press upon the ribs and crowd them out of place, preventing the heart, lungs, and other inside organs from working as they should, causing headache, dyspepsia, shortness of breath, and often ending in some incurable disease, so she knew that _tight clothing means trouble_ to the wearer. [Illustration: FIG. 1. Deformed by tight-lacing.] [Illustration: FIG. 2. A natural, well-shaped chest.] * * * * * QUESTIONS ON THE DESCRIPTION OF THE BONES. Point to the skull. Of what is it made?--"Several bones united together." How are the skull bones united?--"Like two saws with their toothed edges hooked into each other." What do you mean by _toothed_?--"Having points, like teeth." What covers the skull?--"Flesh, skin, and hair." Of what use is the skull?--"It protects the brain." What is the brain?--"That part of my body in which the thinking is done." Where is the spine?--"It extends from the base of my skull behind, down the middle of my back." What do you mean by _extends_?--"Goes from." What do you mean by _base_?--"The lower part of anything." Of what is the spine made?--"Of about twenty-four short bones, with cartilage between them." What is cartilage?--"An elastic substance, harder than flesh, but softer than bone." How are the bones of the spine placed?--"They are piled one upon the other." What do you mean by _forming_?--"Making." What do you mean by _upright_?--"In a vertical position." What do you mean by _flexible_?--"Easily bent." What do you mean by _column_?--"A pillar." What do you mean by _erect_?--"In a vertical position." Why is cartilage placed between the bones of the spine?--"To make the spine flexible; to keep the brain from injury when we walk or run." What do you mean by _elastic_?--"Springing back after having been stretched, squeezed, twisted, or bent." Tell about your ribs.--"My ribs are curved, strong, and light." Where are your ribs?--"On each side of my trunk." How many ribs have you?--"Twenty-four; twelve on each side." How are your ribs fastened?--"At the back to my spine; in front to my breastbone." What do your ribs form?--"A hollow place for my heart, lungs, and stomach." Where are your shoulder blades?--"In the upper part of my back." What shape are they?--"Flat, thin, and like a triangle." Of what use are your shoulder blades?--"For my arms to rest upon." Point to your collar bones. Where are they fastened?--"To my shoulder blades and my breastbone." Of what use are your collar bones?--"They keep my arms from sliding too far forward." Of what are your bones made?--"Of food after it has been changed into blood." Why should you eat wholesome food?--"That my bones may be strong and healthy." How does impure air hurt the bones?--"Impure air makes bad blood, and bad blood makes poor bones." Why should you sit and stand erect?--"Because my bones are easily bent out of shape; if I do not sit and stand erect, they will grow crooked." Why is it wrong to wear tight clothing?--"Because tight clothing crowds the bones out of shape." Whose bones are the more brittle, those of a child, or those of an old person?--"Those of an old person." What do you mean by _brittle_?--"Easily broken." Whose are the more flexible?--"Those of a child." What do you mean by _flexible_?--"Easily bent." What repairs the worn out bones, flesh, and skin of the body?--"The blood." What do you mean by _repairs_?--"Mends." What causes the bones, flesh, and skin of your body to change often?--"The bones, flesh, and skin are always wearing out, and the blood is always building and repairing them again." What are alcoholic liquors?--"Liquors which have alcohol in them." Name some alcoholic liquors.--"Beer, wine, rum, etc." Whose bones mend the more easily when broken, the bones of those who drink alcoholic liquors, or those of the people who do not use these poisons?--"The bones of those who _do not_ use alcoholic liquors." What other poison hurts the bones?--"Tobacco." How do alcohol and tobacco hurt the bones?--"They make bad blood, and bad blood makes poor bones." * * * * * [Illustration: FRONT VIEW OF THE MUSCLES OF THE BODY.] * * * * * PART VI. FORMULA FOR THE LESSON ON THE MUSCLES. 1. Muscles are the red, elastic bands and bundles of thread like substance, called flesh, which cover the bones and make the eyeballs, the eyelids, the tongue, the heart, the lungs, and various other parts of the body. 2. There are about four hundred and fifty muscles in my body. 3. The work of the muscles is to support and move my bones, and different parts of the body. 4. The muscles may be named the muscles of my head, the muscles of my trunk, the muscles of my limbs. 5. The muscles of my head cover and move the parts of my head and face. The muscles of my trunk cover and move the parts of my neck and trunk. The muscles of my limbs cover and mote the parts of my arms and legs. 6. Those muscles are the weakest which I use least; those muscles are the strongest which I exercise most in work or play. 7. If I would be strong and healthy, my muscles must be used, my muscles must be rested, my muscles must be supplied with good blood. I must exercise in work and play to make them strong; I must sleep, or change my kind of work or play, to give them rest, when they are tired; I must breathe pure air, take wholesome food and drink, and live in the sunlight, to supply them with good blood; I must not weaken them by using alcohol or tobacco. * * * * * QUESTIONS FOR THE FORMULA. 1. Tell about the muscles. 2. How many muscles have you in your body? 3. Of what use are the muscles? 4. How may the muscles be named? 5. Tell about the muscles of the head, trunk, and limbs. 6. Which muscles are the weakest, and which are the strongest? 7. What is necessary if you would have strong and healthy muscles? * * * * * CLASSES AND WORK OF THE MUSCLES. The muscles are divided into two great classes: those which we may move as we choose, called _voluntary_ muscles, and those over which we have no power, called _involuntary_ muscles. Some muscles support and move the various parts of the body, others have different work to do. The heart, the great involuntary muscle, acts like an engine to drive the blood throughout the body; the lungs draw in and throw out the air in breathing; the stomach helps to churn and change food into blood; the tongue is used in speaking and eating. * * * * * QUESTIONS ON THE MUSCLES. What are the muscles?--"The lean flesh of the body; bands and bundles of fleshy threads which cover the body." Of what use are the muscles to the body?--"They cover the bones; they support and move the bones and different parts of the body." Name some parts of the body which are made of muscles.--"The eyeballs, the eyelids, the tongue, the heart, the lungs." What color are the muscles?--"Red." How do the muscles move the bones?--"By shortening or lengthening themselves according to the way the bones are to be moved." Tell how the muscles move your arm at the elbow.--"The muscles in the front part of the arm shorten themselves, to draw my fore-arm toward the shoulder; when I wish to stretch out the fore-arm these muscles lengthen, while another set of muscles shorten, to draw the fore-arm away from the upper arm." What do you say about the muscles because they have the power to shorten and lengthen themselves?--"They are elastic." About how many muscles are there in your whole body?--"About four hundred and fifty." How may these be divided as you study about them?--"They may be divided into the muscles of my head, the muscles of my trunk, and the muscles of my limbs." Of what use are the muscles of your head?--"They cover and move the parts of my head and face." Of what use are the muscles of your trunk?--"They move the parts of my neck and trunk." Of what use are the muscles of your limbs?--"They move the parts of my arms and legs." How can you make your muscles strong?--"By using them." How can you make your muscles weak?--"By not using them." What is necessary to make your muscles strong and healthy?--"They must be used; they must be rested when tired; they must be supplied with pure blood." How should the muscles be used?--"They should be exercised in work or play." How may they be rested?--"I may rest my muscles by changing position; by changing my kind of work or play; or by going to sleep." Explain what you mean by changing your position.--"If I am standing, I must sit or lie down to rest them; if they are tired, because I have been sitting too long, I must rest them by standing, walking, or running." What do you mean by changing the kind of work or play?--"If, in my work or play, my arms become tired, I must do something in which my arms may rest, though other parts of my body may be in exercise." How may you help supply your muscles with good blood?--"By breathing pure air; by taking wholesome food and drink; and by living in the sunlight." How does drinking alcoholic liquors hurt the muscles?--"It makes them weak, and unfit to move the parts of the body." What wonderful muscle moves without your will?--"The heart." How does alcohol hurt the heart?--"It makes it beat too fast." How does "beating too fast" hurt the heart?--"It makes it tired, and sometimes wears it out." See Appendices on Alcohol and Tobacco. * * * * * [Illustration: THE SKIN (very highly magnified).--(From Walker's _Physiology_, 1884.)] A, arteries; V, veins; N, nerves; F, fat cells; E, the outer skin; CL, the color layer; D, the true skin; PT, a perspiratory tube; HF, a hair and hair sac; EP, muscles; SG, oil glands; TC, tactile corpuscles; CT, connective tissue. * * * * * PART VII. FORMULA FOR THE LESSON ON THE SKIN. 1. My skin covers my body. 2. It is thin, elastic, flexible, porous, and absorbent. 3. I have two skins; the inner skin is the true skin. 4. My true skin is elastic, and like a net-work of blood-vessels and nerves. My true skin is covered with a jelly-like substance which gives color to my skin. 5. My outside skin is not the same thickness over my whole body. In some parts, as on the palms of my hands and the soles of my feet, it is very thick and tough. 6. If my outside skin be destroyed, it will grow again; if the jelly-like substance be destroyed, it will re-appear; but if my true skin be destroyed, it will never be perfectly renewed. 7. More than half of the waste substance of my body passes from it through the pores of the skin, in the form of perspiration. 8. If I would have a healthy skin, I must perspire freely all the time, I must keep my body clean, I must wear clean clothing, I must breathe pure air, and live in the sunlight. * * * * * QUESTIONS FOR THE FORMULA. 1. Where is your skin? 2. Tell about the skin. 3. How many skins have you? 4. Tell about the true skin. 5. What difference is there in the thickness of your outside skin? 6. What happens if the different skins be destroyed? 7. What passes through the pores of the skin? 8. What is necessary if you would have a healthy skin? * * * * * DIRECTIONS FOR BATHING. Bathe the whole body at least twice every week. Do not bathe when tired or after a hearty meal. After bathing _rub well_ with a coarse towel. * * * * * QUESTIONS ON THE SKIN. Of what use is the skin?--"It covers the muscles of the body." What can you tell about it?--"It is flexible, elastic, porous, and absorbent." Why do you say it is flexible?--"Because it is easily bent." Why do you say it is porous?--"Because it is full of little holes, or pores." Why do you say it is elastic?--"Because it will spring back after it is stretched, squeezed, twisted, or bent." Why do you say it is absorbent?--"Because it will soak up liquids." How many skins have you?--"Two; an outside skin, and an inner skin." Which is the true skin?--"The inner skin." Of what is the inner skin composed?--"Of blood-vessels and nerves." How do you know that the outer skin has no blood-vessels?--"Because if I put a pin through the outer skin the blood does not flow out, as it would if I had cut a blood-vessel." How do you know the outer skin has no nerves?--"Because if I put a pin through my outer skin it does not make me suffer pain, as it would if I had touched a nerve." What gives color to the skin?--"A jelly-like substance between the inner and the outer skin." What have you learned about the true skin?--"That it is of the same color in people of every nation." What difference is there in the thickness of the outer skin? [See Formula.] What passes through the pores of the skin? [See Formula.] What is this waste called when it comes from the surface of the skin?--"Perspiration." When does the perspiration flow through the pores of the skin?--"All the time, if the skin is healthy." Why do we not always see the perspiration which passes through the pores?--"Because it does not always form drops on the surface of the skin; it generally passes off in very fine particles." What becomes of the fine or minute portions of perspiration which pass from the body?--"Some of these portions are absorbed by the clothing; some pass into and mix with the air around us." What effect does the perspiration produce on the air and the clothing?--"It soon makes the air unfit to be breathed, and the clothing unfit to be worn." What is necessary if you would have a healthy skin? [See Formula.] Why must you wear clean clothing?--"That there may be nothing impure in the clothing for the pores of the skin to absorb." Why should you breathe pure air?--"Because air purifies the blood, and pure blood is necessary to make a healthy skin." How does drinking alcoholic liquors hurt the skin?--"It makes the blood impure, and impure blood makes unhealthy skin." In what other way does drinking these liquors hurt the skin?--"It gives the skin too much work to do." How does it give it too much work to do?--"It makes more waste substance to pass from it through the pores, in the form of perspiration." In what other way does drinking alcoholic liquors hurt the skin?--"It makes it a bad color." How does it make the skin a bad color?--"It stretches the little blood-vessels of the skin, and makes them too full of blood." See Appendix. * * * * * [Illustration: THE HEART.] A, the right ventricle; B, the left ventricle; C, the right auricle D, the left auricle; E, the aorta; F, the pulmonary artery. * * * * * PART VIII. FORMULA FOR THE LESSON ON THE HEART AND THE CIRCULATION OF THE BLOOD. 1. My heart is shaped like a cone, and placed in my chest near my breastbone, with its apex pointing downward to my left side. It beats about seventy times a minute, sending out about two ounces of blood at every beat. 2. The blood when pure is of a bright red color; it is a liquid made from food and drink. 3. It passes from my heart to all parts of my body, through pipes called arteries; these arteries spread out through the body like branches from a tree. 4. As the blood flows from the heart, through the arteries, it gives nourishment to every part of the body, and carries away the impurities it meets, which makes it black and thick; when it comes through the veins, back to the heart, it is not fit to be used, so it goes to the lungs to be purified by the fresh air; then it returns to the heart to be sent again throughout the body; this happens once in from three to eight minutes, and is called the circulation of the blood. 7. If I would be healthy, my blood must be pure and circulate freely all the time. 8. It will not circulate freely, if I wear tight clothing, if I do not exercise in work or play, if I do not keep my body warm. 9. It will be impure, if I breathe bad air, if I eat unwholesome food, if I drink alcoholic liquors, if I snuff, smoke, or chew tobacco. * * * * * QUESTIONS FOR THE FORMULA. 1. Tell about the heart and where it is placed. 2. Tell about the blood and of what it is made. 3. Where does the good blood pass after it is sent out from the heart? 4. Tell what the blood does as it flows through the body. 5. What is this flowing of the blood to and from the heart called? 6. How often does it happen? 7. What is necessary if you would have pure blood? 8. When will the blood not circulate freely? 9. When will the blood be impure? * * * * * HOW TO TREAT A WOUND. If it is only a flesh-wound or slight cut, wash it with cold water and bandage it with a clean, white rag. The edges of a deep cut should be drawn together and held in place by narrow strips of adhesive plaster, fastened across the wound from side to side. If the cut is very deep, and the blood flows very freely, send for a doctor. While you wait for him, knot a handkerchief, or suspender, or towel, in the middle, and twist it very tightly _over the cut artery, above the wound_. If a vein has been severed, twist the knotted handkerchief _below the wound_. If the blood continues to flow, tie a bandage both above and below the hurt part. * * * * * QUESTIONS ON THE HEART AND THE CIRCULATION OF THE BLOOD. Of what shape is your heart?--"My heart is shaped like a cone." Where is it placed?--"In the chest, pointing toward my left side." What bone is it near?--"It is near my breastbone." Of what use is the heart?--"It contains the blood and sends it to the different parts of the body." How much blood is sent from the heart at each beat?--"About two ounces." What is the blood?--"A liquid made from food and drink." Of what color is the blood?--"Bright red, when pure; dark red, when impure." How does the heart send the blood through the body?--"Through pipes called arteries." What do the arteries resemble in the way they are arranged?--"The branches of a tree." What makes the blood impure?--"As the blood flows, it gives nourishment to every part of the body; this makes it poor. It also takes up the old worn-out particles; this makes it impure." Where do the arteries carry the impure blood?--"To the veins." Where do the veins carry the impure blood?--"To the heart." Where does the heart carry the impure blood?--"To the lungs." What happens to the impure blood in the lungs?--"It is made pure." What makes it pure?--"Pure air." Where do the lungs send the blood after it is made pure?--"Back to the heart." Where does the heart send the pure blood?--"Throughout the body." What is the journey of the blood to and from the heart to the different parts of the body called?--"The circulation of the blood." What is the circulation of the blood?--"The circulation of the blood is its journey from the heart to the different parts of the body, and from the different parts of the body back to the heart." How often does this circulation take place?--"Once in from three to eight minutes, according as the heart beats fast or slowly." What kind of blood is necessary to health?--"Pure blood." How should the blood circulate?--"Freely, all the time." What do you mean by freely?--"Without anything to hinder." What is necessary for the free circulation of the blood?--"I must wear clean clothing; I must exercise in work or play; I must keep my body warm." How does tight clothing hinder the free circulation of the blood?--"By pressing upon the arteries and veins; and when about the waist, causing the ribs and other parts of the body to press upon the heart." How does exercise help the free circulation of the blood?--"Exercise makes the heart beat faster, which causes the blood to more faster through the arteries and veins." Why does keeping the body warm help the circulation of the blood?--"Because the blood moves faster when it is warmest; cold chills the blood, and makes it move slowly." What harm do alcoholic liquors do to the heart?--"They make it tired, and sometimes wear it out." In what way do they make it tired?--"They make it beat too fast." Why does it beat too fast?--"Because it is hurrying to drive the alcohol out of the body." In what other way do alcoholic liquors hurt the heart?--"They produce disease in it." Tell one way by which the heart becomes diseased through alcoholic liquors?--"Alcohol softens the fibres of the muscles of the heart, and fills them with fat." What harm does this do to the heart?--"It makes it too weak to do its work, which is to pump the blood through the body." What sometimes happens when the heart is thus weakened?--"It stops beating, which causes sudden death." What harm does alcohol do to the blood?--"It uses up the water of the blood; it destroys the goodness of the red part; it makes the blood thin, impure, and unfit to do its work." See Appendices on Alcohol and Tobacco. * * * * * [Illustration: THE LUNGS.] 1, 2, the larynx, the upper part of the windpipe. 3, the windpipe, or trachea. 4, where the windpipe divides to right and left lungs. 5, the right bronchial tube. 6, the left bronchial tube. 7, outline of the right lung. 8, outline of the left lung. 9, the left lung. 10, the right lung. * * * * * PART IX. FORMULA FOR THE LESSON ON THE LUNGS AND RESPIRATION. 1. My lungs are the bellows or breathing machines of my body. 2. They are composed of a soft, fleshy substance, full of small air-cells and tubes. They are porous and spongy when healthy, but in some diseases become an almost solid mass, through which the air cannot pass. 3. I breathe by drawing the air through my windpipe, along the tubes into the cells of my lungs, swelling them out, and causing my chest to expand; then the chest contracts, and the impure vapor in my lungs is pressed out through the same tubes, windpipe, nose, and mouth, into the atmosphere. 4. I cannot live without breathing, because if the air does not go down into my lungs, the dark blood in them is not changed into pure red blood, and goes back through my body dark blood, which cannot keep me alive. 5. If I would have healthy lungs, I must breathe pure air, I must live in the sunlight, I must keep my body clean, I must wear loose clothing, I must wear clean clothing, I must sit and stand erect, I must keep all parts of my body warm, I must not change my winter clothing too early in the spring, I must avoid draughts of cool air, I must not rush into the cold when I am in a perspiration, I must not poison my lungs with alcohol or tobacco. * * * * * QUESTIONS FOR THE FORMULA. 1. What are the lungs? 2. Describe the lungs. 3. How do you breathe? 4. Why can you not live without breathing? 5. What is necessary if you would have healthy lungs? * * * * * THE AIR AND THE LUNGS. The air which enters through the nose and mouth passes into a tube of muscles and ring-like pieces of cartilage. The upper part of this tube is the voice-box or _larynx_, covered by a spoon-shaped lid which closes when we swallow; the lower part is the _trachea_, and the two parts are the windpipe. The trachea divides into two branches, _the bronchial tubes_, one for each lung. These tubes divide again and again like the branches of a tree, and end in exceedingly small sacs or bags. The air in these sacs, or air-cells, gives _oxygen_ to the blood in the tiny blood-vessels of the lungs and takes from them the poison, _carbonic-acid gas_, water, and impurities, which it carries back through the windpipe into the outside air. * * * * * QUESTIONS ON THE LUNGS AND RESPIRATION. Of what are the lungs composed?--"Of a soft, fleshy substance, full of small air-cells and tubes." Of what use are the lungs?--"They are the breathing machines of the body." How do the lungs appear when healthy?--"Porous and spongy." How does the air get into the lungs?--"The air flows through the nose and mouth, into the windpipe and along the air-tubes, into the air-cells of the lungs." What does the air do in the lungs?--"It swells the lungs and causes the chest to expand." What do you mean by expand?--"To increase in size." How is the air expelled from the lungs?--"The chest contracts and sends the impure air through the tubes and windpipe, the nose and mouth, into the atmosphere." What do you mean by contracts?--"Becomes smaller." What do you mean by atmosphere?--"The air." Of what use is the air when it is in the lungs?--"It makes the blood pure." Why can you not live without breathing?--"Because, if I do not breathe, pure air cannot get into the lungs to make the bad blood pure, and I cannot live if the dark, impure blood is sent back again through my body." Why must you live in the sunlight?--"Because the sunlight helps to purify the blood and strengthen the body." Why must you wear loose clothing?--"Because tight clothing stops the circulation of the blood." Why must you avoid tight-lacing?--"Because tight-lacing crowds the ribs against the lungs, so that the lungs cannot move freely." Why should you wear clean clothing?--"That nothing impure may pass into the body through the pores of the skin." Why should you keep the body clean?--"That the pores of the skin may not be closed, but remain open to let the perspiration pass through." What has the cleanliness of the body to do with the health of the lungs?--"If the body is not kept clean, the perspiratory pores become clogged." What happens when the perspiratory pores are clogged?--"The impure particles which should pass through them stay in the body, and cause disease in the lungs or other parts." Why should you sit and stand erect?--"Because, if I am in the habit of stooping, my lungs will be crowded, and will not have enough room to move freely." Why should you keep all parts of the body warm?--"Because chilling any part of the body causes the blood to chill in that part, and thus hinders its circulation." Why should you not change your winter clothing too early in the spring of the year?--"I may take cold if not warmly clothed during the cool days of early spring." Why should you avoid draughts of cool air?--"Because the cool air blows upon some parts of the body and closes the pores of the skin, checking the perspiration, and hindering the circulation of the blood." Why should you not rush suddenly from a warm to a cool place?--"Because when warm the pores of the skin are open; if I rush suddenly into the cool air, these pores are closed too quickly." Why does stopping the perspiration hurt the lungs more or less?--"The impurities it ought to carry away remain in the body, make the blood impure, and produce disease in some part; very often that part is the lungs." What harm does alcohol do in the lungs?--"It fills the lungs with impure blood." What harm does it do to the air-cells?--"It hardens the walls of the air-cells of the lungs." What harm is done by the hardening of these air-cells?--"1. The lungs cannot take in enough of the gas called oxygen to purify the blood perfectly. 2. The gases or vapors in the lungs cannot pass freely through the hardened air-cells." What happens from this?--"The lungs become diseased." From what disease do some hard drinkers suffer?--"Alcoholic consumption, for which there is no cure." See Appendices on Alcohol and Tobacco. * * * * * [Illustration: THE DIGESTIVE ORGANS.] 1. The upper jaw. 2. The lower jaw. 3. The tongue. 4. The roof of the mouth. 5. The food-pipe. 6. The windpipe. 7, 8. Where the saliva is made. 9. The stomach. 10. The liver. 11. Where the bile is made. 12. The duct through which the bile passes to the small intestine. 13. The upper part of the small intestine. 14. Where the pancreatic juice is made. 15. The small intestine. 16. The opening of the small into the large intestine. 17-20. The large intestine. 21. The spleen. 22. The spinal column. * * * * * PART X. FORMULA FOR THE DIGESTIVE ORGANS AND DIGESTION. 1. When my food is chewed, it is rolled by my tongue into the oesophagus, or food-pipe, which is back of my windpipe, and leads from my mouth down along the side of my spine, to the left and upper end of my stomach. 2. My stomach is an oblong, soft, and fleshy bag, extending from my left to my right side, below my lungs and heart. 3. It is composed of three coats or membranes, and resembles tripe. 4. The _outer coat_ is smooth, thick, and tough. It supports and strengthens the stomach. 5. The _middle coat_ is fibrous. Its fibres have the power of contracting, sometimes pressing upon the food, and sometimes pushing it along toward the opening which leads out of the stomach. 6. The _inner coat_ is soft, thick, spongy, and wrinkled. It prepares a slimy substance and a fluid. The slimy substance prevents the stomach from being irritated by the food. The fluid dissolves the food. 7. Food passes through several changes after it enters the mouth. 8. It is changed into pulp in the _mouth_, by the action of the teeth and the saliva. This is called _mastication_. It is changed in the _stomach_, by the action of the stomach and the gastric juice, into another kind of pulp called _chyme_. The chyme is changed by the bile and another kind of juice, called _pancreatic_ _juice_; these separate the nourishing from the waste substance. The nourishing, milk-like substance is called _chyle_. The waste substance passes from the body. The chyle is poured into a vein behind the collar bone, and passes through the heart to the lungs, where it is changed into blood. 9. If I would have a healthy stomach, I must be careful what kind of food I eat, I must be careful how much I eat, I must be careful how I eat, I must be careful when I eat. 10. I must eat wholesome food, good bread, ripe fruits, rather than rich pies or jellies. 11. I must eat enough food, but not too much. 12. I must eat slowly, I must masticate my food thoroughly, I must masticate and swallow ray food without drinking 13. I must take my food regularly but not too often, I must rest before and after eating, if possible, I must not eat just before bedtime. 14. I must breathe pure air, I must sit, stand, and walk erect, I must not drink alcoholic liquors, I must not snuff, smoke, or chew tobacco. * * * * * QUESTIONS FOR THE FORMULA. 1. Describe the process of eating.[2] See page 21. 2. Where does the food go after it is chewed? 3. Describe the stomach. 4. Of what is the stomach composed? 5. Describe the outer coat of the stomach, and tell its use. 6. Describe the middle coat of the stomach, and tell its use. 7. Describe the inner coat of the stomach, and tell its use. 8. What happens to the food after it enters the mouth? 9. Tell about these changes. 10. What is necessary if you would have a healthy stomach? 11. What kind of food must you eat? 12. How much food must you eat? 13. How must you eat? 14. When must you eat? 15. What other rules must you obey? [2] See Formula 7 on the Organs of Sense. * * * * * "EAT TO LIVE, NOT LIVE TO EAT." There is pleasure in eating, because God has given us the sense of taste, that we may enjoy our food. But not everything which pleases this sense is good for the body, so we should learn what things are wholesome and choose them for our food and drink, refusing everything which is unwholesome. Those who obey these rules "_eat to live_" and never become drunkards or gluttons. * * * * * QUESTIONS ON THE DIGESTIVE ORGANS AND DIGESTION. What happens to the food after it is chewed?--"It is rolled by my tongue into the oesophagus or food-pipe." Where is the oesophagus or food-pipe?--"It passes from the mouth down the left side of the spine." What is the stomach?--"A fleshy bag which receives and changes the food we eat." Where is the stomach?--"In the front part of the chest, below the heart and lungs." Of what is the stomach composed?--"Of three coats or membranes." What do you mean by composed?--"Made of." What do you mean by membrane?--"A thin skin." What are the coats of the stomach called?--"The outer coat, the middle coat, the inner coat." Describe the outer coat of the stomach.--"The outer coat is smooth, thick, and tough." Of what use is the outer coat of the stomach?--"It strengthens and supports the stomach." What do you mean by supports?--"Holds." Describe the middle coat of the stomach.--"The middle coat is composed of fleshy fibres, which have the power of making themselves long or short." What do you mean by fibrous?--"Composed of threads." What do you mean by fibres?--"Threads." Of what are the fibres of the stomach composed?--"Of flesh." Of what use are the fibres of the stomach?--"They press upon the food, and push it toward the opening which leads out of the stomach." Describe the inner coat of the stomach.--"The inner coat is soft, thick, spongy, and wrinkled." Of what use is the inner coat of the stomach?--"It prepares a slimy substance and a fluid." Of what use is the slimy substance?--"It prevents the stomach from being irritated by the food." Of what use is the fluid?--"It dissolves the food." What do you mean by slimy?--"Soft, moist, and sticky." What do you mean by irritate?--"To produce unhealthy action." What do you mean by dissolves?--"Melts." Where is the food changed after it is taken into the mouth?--"First it is changed in the mouth; second, it is changed in the stomach; third, it is changed after leaving the stomach; fourth, it is changed in the lungs." By what is it changed in the mouth?--"By the action of the teeth and the saliva." By what is it changed in the stomach?--"By the action of the stomach and a kind of fluid called gastric juice." By what is it changed after leaving the stomach?--"By the action of the bile and the pancreatic juice." By what is it changed in the lungs?--"Nobody knows." Into what is it changed in the mouth?--"Into pulp." Into what is it changed after leaving the stomach?--"Into chyle and waste substance." Into what is it changed in the lungs?--"Into blood." What is the change in the mouth called?--"Mastication, or chewing." What is the change in the stomach called?--"Chymification, or chyme-making." What is the change after leaving the stomach called?--"Chylification, or chyle-making." What is necessary, if you would have a healthy stomach?--"I must be careful what kind of food I eat; how much I eat; and when I eat." What kind of food must you eat?--"Wholesome food, etc." See Formula. How much must you eat?--"Enough, but not too much." How must you eat?--"Slowly." How should your food be masticated?--"Thoroughly." When must you eat?--"Regularly, but not too often." When should you avoid eating?--"Just before bedtime." What kind of air should you breathe?--"Pure air." How should you sit, stand, and walk?--"Erect." Why should you not eat too much food?--"Because, if I eat too much food, my stomach will have too much work to do in changing it into chyme." Why should you eat slowly?--"That I may have time to masticate the food thoroughly." Why should you masticate your food thoroughly?--"That it may be well prepared to enter the stomach." Why should the food be well prepared to enter the stomach?--"Because, if it is not well prepared in the mouth, the stomach will have too much work to change it into chyme." Why should you eat regularly, but not too often?--"Because the stomach needs rest, which it cannot have, if I eat too often." Why should you avoid eating just before bedtime?--"Because, while I am asleep, the stomach cannot do the work of changing the food as it ought to be changed; because the stomach should rest with the other parts of the body." Why should you breathe pure air?--"Because pure air helps to make pure blood, which the stomach needs to make it strong and healthy." Why should you sit, stand, and walk erect?--"That the stomach may not be crowded out of its place, or pressed upon by other parts of the body." In what way does tobacco hurt the stomach?--"It poisons the saliva and prevents it from preparing the food to enter the stomach." What harm does tobacco do inside the stomach?--"It weakens the stomach and makes it unfit to change the food into chyme." How will wise children treat tobacco?--"Let it alone. They will not chew, snuff, or smoke the vile weed." Is alcohol food or poison?--"It is poison." How do we know it is not food?--"Because it cannot be changed into blood." How has this been proved?--"Alcohol has been found in the brain, and other parts of drunkards, with the same smell and the same power to burn easily which it had when it was taken into the mouth." How do you know it is a poison?--"Because it does harm to every part of the body, beginning in the stomach." What harm does alcohol do in the stomach?--"It hinders the stomach from doing its work; it burns the coats of the stomach; it destroys the gastric juice; it hardens the food, so that it cannot be dissolved by the gastric juice." What does the stomach do with alcohol?--"Drives it out as soon as possible." Where does the stomach send it?--"Into the liver." Where does the liver send it?--"To the heart; and the heart sends it to the lungs." What do the lungs do with the alcohol?--"They drive it out as soon as they can." Where do the lungs send some of it?--"Through the nose and mouth, into the air." What harm does the alcohol do in the breath?--"It poisons the air; it tells that some kind of alcoholic liquor has been taken into the stomach." From what you have learned about alcohol, what do you think is the only safe rule to obey concerning cider, beer, wine, and all alcoholic liquors?--"I must not drink them, if I wish to have a strong and healthy stomach." * * * * * [Illustration: THE NERVOUS SYSTEM.--(From Walker's _Physiology_.)] 1. The large brain. 2. The small brain. 3. The spinal cord. 4, 5. Nerves. * * * * * PART XI. FORMULA FOR THE LESSON ON THE NERVOUS SYSTEM. 1. My brain is a soft gray-and-white mass resembling marrow. 2. It is placed in a bony box called the skull; it is covered and held together by three coats or membranes. 3. The outer membrane is thick and firm; it strengthens and supports the brain. 4. The middle membrane is thick, and somewhat like a spider's web in appearance. 5. The inner membrane is a network of blood-vessels. 6. From the brain, white or reddish gray pulpy cords, called nerves, pass to all parts of the body. These nerves are of two kinds: nerves of feeling, and nerves of motion. 7. If I prick my finger, a nerve of feeling carries the message to my brain; if I wish to move my finger, a nerve of motion causes my finger to obey my will. 8. Twelve pairs of nerves pass from the base of the brain: the first pair, called the nerves of smell, to my nose; the fourth pair, called the nerves of sight, to my eyes; the fifth pair, called the nerves of taste, to my mouth, tongue, and teeth. One pair pass to my face; another to my ears. The ninth, tenth, eleventh, and twelfth pairs to my tongue and parts of my throat and neck.[3] 9. The spinal cord is a bundle of nerves extending from the base of my brain, down through the whole length of my spine, or backbone. It is the largest nerve in my body. 10. From the spine, thirty-one pairs of nerves, called _spinal nerves_, pass to different parts of my body; some to the lungs, some to the heart, some to the stomach, some to the bones, and some to the muscles and skin. 11. If a nerve be destroyed it cannot carry messages to and from the brain. Before filling a tooth, the dentist sometimes destroys its nerve. 12. If a nerve be pressed upon too long it cannot perform its duty. If I press upon the nerve passing to my foot, I stop it from communicating with the brain; the foot loses its feeling, or, as I say, "is asleep." 13. If I drink alcoholic liquors, or snuff, smoke, or chew tobacco, my brain and nerves cannot do their work well; because alcohol and nicotine are very poisonous to the brain and nerves. 14. The brain must be supplied with good blood; The brain must be used; The brain must be rested; I must drink wholesome drink, eat wholesome food, take enough exercise, and breathe pure air, that my brain may be supplied with pure blood; I must study and think, that my brain may grow and be strong for work; I must rest my brain when it is tired, either by changing my employment, or by going to sleep; I must not poison my brain with alcohol or tobacco. [3] NOTE.--_A fuller description of the Nerves of the Brain_: Twelve pairs of nerves pass from the base of the brain; the first pair, called the nerves of smell, to my nose; the second pair, called the nerves of sight, to my eyes; the third, fourth, and sixth pairs to the muscles of my eyes; the fifth pair to my forehead, eyes, nose, ears, tongue, teeth, and different parts of my face; the seventh pair to different parts of my face; the eighth pair, called the nerves of hearing, to the inner part of my ear; the ninth pair to my mouth, tongue, and throat; the twelfth pair to my tongue; the eleventh pair to my neck; the tenth pair to my neck, throat, lungs, stomach, and different parts of my body. * * * * * QUESTIONS ON THE FORMULA. 1. Describe the brain. 2. Where is the brain placed? 3. Describe the outer membrane of the brain. 4. Describe the middle membrane of the brain. 5. Describe the inner membrane of the brain. 6. Tell about the nerves. 7. Tell about the use of the two kinds of nerves. 8. Tell about the nerves which pass from the brain. 9. Tell about the spinal cord. 10. Tell about the nerves which pass from the spinal cord. 11. What happens if a nerve be destroyed? 12. What happens if a nerve be pressed upon too long? 13. What happens if you drink alcoholic liquors, or snuff, smoke, or chew tobacco? 14. What is necessary if you would have a healthy brain? * * * * * THE BRAIN AND ITS WORK. The brain is egg-shaped, and of two parts, the large brain (_cerebrum_), and the little brain (_cerebellum_). These are composed of a white and gray substance, which in the large brain is so folded and wrinkled that it looks like the meat of an English walnut; in the little brain it is so arranged that it resembles a tree, and is called _arbor vitae_, tree of life. The mind does its thinking through the large brain, and controls its muscles through the little brain. A drunken man can not walk straight because alcohol has hurt the little brain; he can not think straight because it has poisoned the large brain. * * * * * [Illustration: THE BRAIN AND THE SPINAL CORD.] C, the large brain (_cerebrum_). B, the small brain (_cerebellum_). S, a portion of the spinal cord. * * * * * QUESTIONS ON THE NERVOUS SYSTEM. Where is your brain?--"In my skull." What color is the brain?--"Gray and white." What does the brain resemble?--"Marrow." How is the brain protected?--"By three coats or membranes." What may you name these membranes?--"The outer membrane, the middle membrane, and the inner membrane." Describe the outer membrane. See Formula. Describe the middle membrane. See Formula. What are the nerves?--"White ashen-gray pulpy cords, which are found in the brain." Where do they go from the brain?--"To every part of the body." How many kinds of nerves have you?--"Two." What names are given to the two kinds of nerves?--"Nerves of motion and nerves of feeling." Which is the largest nerve in the body?--"The spinal cord." Where is the spinal cord?--"It extends from the brain throughout the whole length of the backbone." How may you describe the spinal cord?--"It is a bundle of nerves, etc." See Formula. Where are the spinal nerves?--"They pass from the spinal cord to different parts of the trunk and limbs." How many pairs of nerves pass from the base of the brain?--"Twelve." Where do the first pair go?--"To the nose." What are they called?--"The nerves of smell." Where do the second pair go?--"To the eyes." What are the second pair called?--"The nerves of sight." Which move the muscles of the eyes?--"The third, fourth, and sixth pairs." Where do the fifth pair go?--"To the forehead, eyes, nose, ears, tongue, teeth, and different parts of the face." The seventh pair?--"To the different parts of the face." The eighth pair?--"To the inner ear." What are the eighth pair called?--"The nerves of hearing." Where do the ninth pair go?--"To the mouth, tongue, and throat." Where do the twelfth pair go?--"To the tongue." Where do the eleventh pair go?--"To the neck." Where do the tenth pair go?--"To the neck, throat, lungs, stomach, and different parts of the body." What happens if a nerve be destroyed?--"It cannot carry messages to the brain." What happens if a nerve be pressed upon too long?--"It cannot carry messages to the brain." What is necessary if you would have a strong, healthy brain?--"My brain must be used; my brain must be rested; my brain must be supplied with pure blood." How must you use your brain?--"In thinking and studying." How may the brain be rested?--"By sleep." In what other way may the brain be rested?--"By thinking of something different from that which made it tired." What two brain-poisons have you learned about?--"Alcohol and tobacco."[4] With what may you show the harm done by alcohol to the gray part of the brain?--"With alcohol and the white of an egg." How could you show it with these?--"I would pour the alcohol upon the white of the egg." What would then happen?--"The white of the egg would harden as if it had been boiled." What is in the white of an egg?--"Water and albumen." Where else may we find albumen?--"In some seeds, and in the gray part of the brain and the nerves." What harm does alcohol do to the nerves?--"It takes away their moisture and hardens them." What harm does this do to them?--"It paralyzes them, or makes them lose their power." What happens when nerves are paralyzed?--"They lose their power over the muscles; they are unfit to carry messages to and from the brain." What harm does alcohol do to the gray part of the brain?--"It hardens it, as it hardens the white of an egg." What harm does this do to the brain?--"It paralyzes it, or makes it lose its power." What then happens?--"It cannot properly do its work of thinking, and cannot control the nerves." What disease is sometimes caused by this hardening of the brain by alcohol?--"Paralysis, which often ends in death." What harm does alcohol do to the blood-vessels of the brain?--"It fills them with impure blood." What disease is caused by the blood-vessels of the brain being filled with impure blood?--"Congestion of the brain, or apoplexy, which ends in death." What else frequently happens to those who drink alcoholic liquors?--"They become crazy, or insane." If you wish to have a strong, healthy brain, what should you do about these liquors?-- "Never put them into my mouth, To steal away my brains." Tell of what dreadful disease people die who are bitten by a mad dog.--"Of hydrophobia." Of what dreadful disease do people sometimes die who are bitten by the serpent in alcoholic liquors?--"Of delirium tremens." Which is the more dreadful, hydrophobia or delirium tremens?--"One is as dreadful as the other." How can you be sure never to have delirium tremens?--"By drinking nothing which has alcohol in it." Will a little beer or wine hurt you?--"Yes, it may make me love the taste of alcohol." What harm is there in loving the taste of alcohol?--"I may love it so much as to become a drunkard." Tell once more how you should treat alcoholic liquors.--"I should never drink a drop of them." [4] See Appendices. * * * * * ALCOHOL. THE STORY ABOUT ALCOHOL. Several hundred years ago many people were trying to discover something that would keep them young and strong, and prevent them from dying. It is said by some that a man named Paracelsus, in making experiments, discovered _alcohol_. He called it "the water of life," and boasted that he would never be weak and never die; so he went on drinking alcoholic liquors until at last he died in a drunken fit. What is this alcohol which has done and is doing so much mischief in the world? I will show you some. What does it look like?--"Water." Yes; and if you were to smell it you would say it has a somewhat pleasant odor; if you were to taste it, that it has a hot, biting taste, _i.e._, is pungent. If you put a lighted match to it you would notice that it burns easily, and with a flame, and may therefore be said to be combustible and inflammable. What does it come from? Is it one of the drinks God has given us? Some of the class think it is; we will try to learn whether this answer is correct or not. If we study about it very carefully we shall discover that it is not a natural drink, that it is not found except where it has been made from decayed or rotten fruits, grains, or vegetables. If you take some apples, and squeeze the juice out of them, you will find it sweet and pleasant; let that juice stand for several days and what will happen to it?--"It will get bad." Yes; or, as grown people say, it will _work_ or _ferment_; that is, the sugary part of the juice will be separated into a kind of gas and a liquid. The gas is called _carbonic acid gas_; the liquid is _alcohol_. Both the gas and the liquid are poisonous. Alcohol may also be obtained from other fruits, as grapes, and from some grains and vegetables. But all these must first become rotten before alcohol will come out of them. This is one reason why we think that God, who gives us good, wholesome food, did not intend alcohol to be a drink for man, else He would have put it into the delicious ripe fruit, and not made it impossible to get until they decay. Now let us put upon the blackboard something which will help us remember what we have learned about ALCOHOL. DISCOVERED BY DESCRIPTION. MADE FROM Paracelsus. Water-like; with a Fruits, Grains, or pleasant odor; a Vegetables. CALLED hot, biting taste; "The water of life." and will burn with a flame. * * * * * USES OF ALCOHOL. We put some sugar into water; the children see that it melts; then some glue or shellac is placed in the same liquid; they see that this is not melted, but that, when alcohol is used instead of water, the glue or shellac is dissolved. From this experiment they learn that alcohol is used in making varnishes. Some water is poured into one saucer, and alcohol into another; a lighted match is applied to each; the class notices that the alcohol takes fire and burns, while the water does not. Next, we fill a lamp with alcohol, and put a wick into it; when the wick becomes wet with the fluid it burns steadily and without smoke, as may be seen by holding a clean white saucer over the flame. This shows why jewellers and others, who wish to use a lamp to make things very hot, prefer alcohol to kerosene, which, as the children know, smokes lamp-chimneys, or anything else, so easily. We show a thermometer; the children are told its use if they are not already familiar with the instrument; we talk about the quicksilver in the tube, about its rising or falling according to the degree of heat or cold; then we inform the class that in some countries where it is very cold quicksilver freezes; for this reason alcohol, which does not freeze, is colored red and put into the thermometer tube to be used in these Arctic regions. Another use for alcohol is to keep or preserve substances. This we illustrate by placing a piece of meat into some alcohol. We explain that the water in the meat is that which causes it to decay. Alcohol has the power to take up or _absorb_ water; so when meat is put into this liquid the water from the meat is absorbed by it, and the meat does not become bad. Those who wish to preserve insects a long time, and doctors who desire to keep any portion of a human body after death, put these into alcohol, in which they may be kept for a long time. Lastly, we let the children smell cologne or other perfumery, and tell them this is made from different oils mixed with alcohol. At the close of this lesson the class is ready to help us make the following BLACKBOARD OUTLINE. FACTS ABOUT ALCOHOL. GOOD USES OF ALCOHOL. It melts gums. To melt gums. Burns with a flame. To make varnishes. Burns without smoke. To burn in lamps. Will not freeze. To make camphene, etc. Likes water. To put into thermometer Mixes with oils. tubes. To preserve meats, etc. To make perfumery. In making jewelry. * * * * * USES OF ALCOHOL--_concluded_. You see alcohol is very useful for some purposes; but do people ever drink it? Some of the children think not, and we grant that no one is foolish enough to drink _raw_ alcohol, because it is too strong. It would take only a little to make them drunk, and only a few ounces to kill them instantly. We ask the pupils if they have ever seen a drunken person, and what made that person drunk? We soon obtain an answer, and place upon the board "Rum, gin, whiskey, brandy," as the names of drinks which will take away the good sense of those who drink them. To these are added "Wine, beer, ale, lager, and cider." We explain that all these have alcohol in them, as may be known by smelling them, or by smelling the breath of those who have drunk even a little of them; and that because they contain alcohol they are called _alcoholic liquors_. If a person drinks any one of them he will be poisoned, more or less, according to how much he takes. The children are astonished at the word _poisoned_, but we explain that the very word, _intoxicated_, means poisoned. So a drunken man is a poisoned man. If enough alcohol, or alcoholic liquor, is drunk by anyone, he will drop down dead as quickly as if he were shot by a cannon ball. When told that alcohol is not a food, but a poison, the class readily understands what we mean, and we have no difficulty in having the following statements prepared and memorized: * * * * * FOOD. That which makes the body grow, and helps to keep it alive. POISON. That which hurts the body, and makes it die. ALCOHOL. QUALITIES. GOOD USES. Water-like, _looks like To melt gums. water_. To make varnishes. Transparent, _may be seen To burn in lamps. through clearly_. To make camphene, etc. Odorous, _has a smell_. To put in thermometer Pungent, _has a hot, biting tubes. taste_. To preserve meats, insects, Liquid, _will flow in etc. drops_. To make perfumery. Poisonous, _hurts the In making jewelry. body_. Intoxicating, _takes away the BAD USE. senses; makes drunk_. To drink. Absorbent, _takes up or absorbs water_. Inflammable, _burns with a flame_. Uncongealable, _will not freeze_. Innutritious, _not good for food_. * * * * * ABOUT FERMENTATION AND FERMENTED LIQUOR. _ALCOHOL._--Alcohol may be obtained from any substance which contains sugar or starch, or both sugar and starch, as apples, pears, grapes, potatoes, beets, rice, barley, maple, honey, etc. Alcohol can be obtained only by _fermentation_. By fermentation we mean the change which takes place when a juice containing sugar decays, or goes to pieces. You know decay always makes things fall to pieces. You ask, what pieces is sugar made of? Very, very little pieces, called _atoms_. There are different kinds of sugar. In that made from grapes, called _grape sugar_, there are six atoms of carbon, twelve of hydrogen, and six of oxygen. What are carbon, hydrogen, and oxygen? Oxygen is the kind of gas which keeps animals alive, and makes things burn. Hydrogen is another kind, which you have smelled perhaps when water has been spilled on a hot stove; the gas burned in street-lamps is hydrogen that has been driven out of coal. Carbon you see in charcoal and soot; the black lead of your lead-pencils is mostly composed of carbon and iron; lamp-black is pure carbon, without form or shape. We will let these circles of colored paper stand for the atoms of carbon, hydrogen, and oxygen in grape sugar,--the largest, which are red, for the oxygen; the second size, which you notice are black, will represent atoms of carbon; while the little blue ones will make you think of hydrogen. If you remember that it takes one atom of carbon and two of oxygen to make carbonic acid gas; also, that two atoms of carbon, one of oxygen, and six of hydrogen to form alcohol, you can easily find that two atoms of carbonic acid gas and two atoms of alcohol may be formed from an atom of sugar. So the more sugar a juice contains the more alcohol may be formed from it. _CIDER._--Cider is made by pressing the juice out of apples. This sweet cider ferments, and the sugar part of it changes into carbonic acid gas and alcohol. People who do not understand this go on drinking cider, not knowing that it makes drunkards of those who drink much of a beverage which seems so pleasant and harmless. _WINES._--Wines are made from the juices of fruits which have sugar in them, especially grapes. Sometimes people have what they call _home-made wines_, which they make from blackberries, currants, elderberries, gooseberries, cherries, or other fruits. They may ask you to take some, saying, "This will do you no harm; we did not put any alcohol into it." They do not know what you have learned, that alcohol is always formed in fermented juices which contain sugar. It does not wait to be put into the home-made wines; it quietly comes in as they are getting made, at home or any other place, and will make people drunk as surely as when it is found in brandy or any other liquor. Some of the wines in the stores are made from grape juice, but many more are made by mixing hurtful and poisonous things together to make the liquor strong, and give it what is called a fine color and good taste. _BEER AND ALES._--These are made from grains and hops, which contain no sugar, it is true, but are composed of starch, which may be changed into sugar. When a seed of grain is put into the ground and begins to grow, the starch in it becomes sugar, which feeds the young plant. When a brewer wishes to make beer, he takes some grain, puts it in a dark place, wets it, and leaves it to sprout, or begin to grow. Then he puts it into an oven to dry it, and make it stop growing. This makes what is called _malt_. The malt is mashed and soaked in warm water to get the sugar out of it; this forms a liquid called _sweet wort_. The wort is separated from the mashed grain and boiled; yeast is mixed with it to help it to ferment more quickly; it soon becomes changed; a dirty yellow scum filled with bubbles comes to the top, which we know is the poisonous carbonic acid gas; the other poison, alcohol, stays in the liquid and makes the beer taste good to those who like it. Liquors made from grain are called _malt liquors_. Lager beer, and all kinds of ales and porters, are malt liquors. They make people dull, sluggish, and stupid who drink much of them. They do much mischief in the body, though it takes a larger quantity of any one of them to make a person drunk than it does of whiskey or brandy. AN ATOM OF GRAPE SUGAR. CARBONIC ACID GAS. ALCOHOL. Carbon, 6 atoms. Carbon, 1 atom. Carbon, 2 atoms. Oxygen, 6 atoms. Oxygen, 2 atoms. Oxygen, 1 atom. Hydrogen, 12 atoms. Hydrogen, 6 atoms. SUB-FERMENTED GRAPE SUGAR MAKES 2 atoms of carbonic acid gas and 2 atoms of alcohol. ALCOHOLIC LIQUORS MADE FROM FRUITS. GRAINS. _Cider._ _Wines._ _Beer, Ales, etc._ Apples. Grapes, Gooseberries, Barley, Oats, _Perry._ Currants, Elderberries, Wheat, Peas, etc. Pears. Blackberries, Cherries, etc. Corn, (with hops). * * * * * DISTILLATION. How does the sugar in grapes and other fruits become alcohol?--"By fermenting." Yes, and liquors made by fermenting are called _fermented liquors_. What other alcoholic drinks have you heard about beside cider, wines, beer, and ales?--"Gin, whiskey, brandy, rum." These are stronger than the fermented liquors, that is, they contain more alcohol; they are made by what is called _distillation_. If you boil water, and let the steam from it fall upon a cold plate, the steam will change back into liquid and become _distilled_ water. Making a liquid boil, catching the vapor or steam and cooling it, is what we mean by distillation. If two or more liquids are mixed together, the one that boils with the least heat will be drawn off first. The alcohol of beer, cider, and wines is mixed with water; it boils at a lower heat than water, so can be drawn off from it very easily. This does not make more alcohol, it only makes the alcohol stronger by separating it from the water. When beer or any other alcoholic liquor is to be distilled, it is poured into a large copper boiler, called a _still_, and boiled. A tube carries the vapor from the boiler into a cask filled with cold water. This tube is coiled like a spiral line or worm through the cask; it is called _the worm of the still_, and the cask is _the worm-tub_. As the vapor passes through the tube, it cools and drops out at the end into the worm-tub, changed into a liquid stronger in alcohol than that from which it was drawn or distilled. In this way gin is made from beer, brandy from wine, and rum from fermented molasses. These are very strong drinks, and only hard drinkers like them. But very few people begin by taking these; they first learn to like alcohol by drinking cider, beer, or wine, and end with gin, whiskey, or rum when they have become drunkards. DEFINITIONS. _DISTILLATION._ Drawing the vapor from a boiling liquid and cooling it. _STILL._ Machinery for distilling; the boiler which holds the liquid. _THE WORM OF THE STILL._ The tube which passes from the still to a cask, in which it coils like a worm. _WORM-TUB._ The cask which holds the tube or worm, and receives the distilled liquid. _DISTILLED LIQUID._ A liquid formed by cooled steam. _DISTILLED LIQUORS._ Liquors made by distilling alcoholic liquors. _FERMENTED._ Changed by decay. _FERMENTED LIQUORS._ Liquors which have been fermented or changed by decay, and contain alcohol. _UNFERMENTED._ Not decayed. _UNFERMENTED LIQUORS._ Liquors which contain no alcohol. KINDS OF LIQUORS [5]UNFERMENTED. FERMENTED. DISTILLED. Grape juice, Hard cider, Gin, Sweet cider, (Malt liquors) Brandy, Root beer, Beer, Whiskey, Ginger beer. Lager beer, Rum. Perry. Ale, Porter, Wine. [5] These soon become fermented; they then contain alcohol. * * * * * HARM DONE BY ALCOHOL IN VARIOUS PARTS OF THE BODY. Raw alcohol does not do much harm to people because it is too strong for them to drink much of it; but the alcohol hidden in cider, ale, wine, whiskey, and other alcoholic drinks kills not less than _sixty thousand_ persons in this country every year, besides those who die from its use in other parts of the world. There is great excitement when there is a mad dog around; and, if any one is bitten and dies from the dreadful hydrophobia, people are ready to destroy all the dogs of the neighborhood; but when a drunkard dies from delirium tremens or alcohol craziness, how few take any notice of the cause of his death, or do all they can to wage war against the use of alcoholic liquors. But why do we say such hard things against these liquors which some people love so well and think so harmless? In what way do they hurt and kill people? Let us see. Where does what we drink go after it has been put into the mouth?--"Into the stomach." If it were the right thing to go into the stomach, into what would it be changed?--"Into something which helps to make good blood." Learned men, who have examined and carefully studied about these things, tell us that _the stomach is hurt_ by alcohol, because the fiery fluid is not food, but poison which makes the stomach very sore, and gives it hard work to do. The veins of the stomach take it up and send it into the liver. The liver, which is a large organ weighing about four pounds, lies on the right side below the lungs; its work is, to help make the blood pure. It can do nothing with alcohol, so it drives it along to the heart; the heart sends it to the lungs; the lungs throw some of it out through the breath, which smells of the vile stuff that has been poisoning every part it has passed through since it entered the mouth. Some of the alcohol does not get out of the lungs through the breath, but goes with the blood back to the heart, and from the heart is sent through the arteries to every part of the body. No part of the body wants it. _The Skin_ drives some of it out, through its little pores, with the perspiration. _The Kidneys_, which lie in the back below the waist, on each side of the spine, send off some of the poison. Yet some of it gets into _the brain_, and there does very much mischief, of which you will learn more by and by. You know, if the brain is hurt, the mind cannot do its work of thinking properly; thus, alcohol does great _harm to the mind_ through the brain. _The muscles_ and _the bones_ are hurt by not being supplied with pure blood; _the heart_ gets tired out with overwork, and _the lungs_ become diseased through this same terrible alcohol. Therefore, if you would be strong and healthy, have nothing to do with alcoholic liquors; for ALCOHOL POISONS The stomach, The liver, The blood, The heart, The lungs, The brain, The bones, The muscles, The skin, And every part of the body. * * * * * IN THE STOMACH. Children who have learned the Lesson on Digestion, and know about the coats of the stomach, about mastication and chyme-making, are easily made to understand why anything which has alcohol in it is unfit to go into the stomach. If we touch a drop of alcohol to the eye, it will make it sore; so alcohol in the stomach irritates its coats and makes them sore. Alcohol poisons the gastric juice. If we get some of this juice from the stomach of a calf which has just been killed, and mix alcohol with it, the alcohol will separate the watery part from the _pepsin_ or white part. This is what alcohol does in the stomach. It takes up water from the gastric juice, which prevents the pepsin from mixing well with the food, and hinders the change of the food into chyme, which cannot take place without pepsin. The children have already learned that alcohol keeps meat from decaying, or going to pieces. We explain that food in the stomach must go to pieces to prepare it to make blood; when mixed with alcohol, it is preserved, and the gastric juice cannot melt or dissolve it. Thus the stomach is hindered from doing its work until it gets rid of the alcohol. A true story we have read will help you to remember how troublesome alcohol is to the stomach. Some men in Edinburgh were paid their wages, one Saturday, soon after they had eaten their dinner. They got drunk and remained so till the next day at noon. When they became sober they had a headache and were so ill that they sent for a doctor; he gave them some medicine which brought up their Saturday's dinner just as it had gone down into the stomach. The poor stomach could do nothing with dinner mixed with whiskey or rum, because these liquors are half alcohol. You have already learned that the stomach hurries to drive out the alcohol into the liver; the liver sends it with the blood into the heart; the heart pours it into the lungs; the lungs breathe it out through the nose and mouth, and tell that some kind of alcoholic liquor has been taken into the stomach. Remember, that the alcohol which comes out in the breath is a part of that which _went into the mouth_. It could not be changed. It did nothing but mischief in its journey, which shows that it is not food, but poison. God, who created the body, has not given any part of it power to change alcohol into blood. People sometimes take ale or wine because they think it gives them an appetite. This is a great mistake. When any alcoholic liquor goes into the stomach, there is such hard work to get it out that the pain of hunger is not felt; when it is out, the stomach is tired and does not tell the brain that it is hungry. When alcohol is poured into it, day after day, it loses its desire for good, wholesome food, _and wants more and more alcoholic liquor_. It has an appetite for alcohol. Alcohol makes the stomach sore and full of disease; people who take much of it in liquors always suffer much from dyspepsia. So, if the stomach could speak, it would say: "Don't pour any alcohol into me, though you mix it and call it ale, cider, wine, or any other name that makes folks think it will do me no harm. You cannot deceive me. I know alcohol as soon as it comes down, and it always makes me suffer." * * * * * BLACKBOARD OUTLINE. ALCOHOL-- Burns or inflames the coats of the stomach. Spoils the gastric juice. Makes the food hard to be dissolved. Makes the stomach tired and weak. Takes away the appetite for wholesome food. Makes an appetite for alcoholic liquors. Causes disease in the stomach and other digestive organs. * * * * * QUESTION ON BLACKBOARD OUTLINE. What harm does alcohol do in the stomach? * * * * * TO THE BONES, MUSCLES, AND SKIN. _TO THE BONES._--You have already learned that the bones require to be supplied with good blood to make them strong and healthy, and that alcohol does not make good blood, so we need spend no time in deciding that alcoholic liquors do injury to the bones, and that the bones of those who drink these liquors are less likely to heal, when broken, than those of persons whose blood has not been poisoned by alcohol. _TO THE MUSCLES._--The muscles, as you know, cover and move the bones; good blood makes them grow, and keeps them healthy and strong. People like to have plenty of good muscle, for this not only gives them strength, but makes them look plump and well. Alcohol poisons the blood by killing many of the very little, round, red parts in it, called by a long name, which you can learn if you try. This hard name is _corpuscles_ [kor'pussls]; _corpuscle_ means _a little body_. These little bodies float in the fluid portion of the blood, and go to every part of the body to help keep it alive and healthy. When alcohol hurts them, they turn into a poor kind of fat, like suet, and cannot do any good. They stay in different parts and do much harm. Sometimes they lodge between the muscles, and make a person look strong because plump; but he is not strong, for his muscles are filled with fat. Sometimes the liver or the heart, which are only large muscles, become so heavy and soft with fat that they cannot do their work properly; they become weak and diseased, wear out, and cause the death of their owner, who has poisoned them with ale, wine, or other alcoholic drink. _TO THE SKIN._--Alcohol hurts the skin also, by feeding it with poisoned blood, by giving the pores extra work in carrying off some of the alcohol in the perspiration, and by making the little blood-vessels larger than they should be in a way you will learn more about by and by. These little blood-vessels become very full of blood, and cause the red face and blue nose which mark the drinker of alcoholic liquors. This redness of the skin tells of the mischief which alcohol is doing inside of the body. It is the danger-signal which warns against the use of the fiery poison. ALCOHOL HURTS THE BONES, THE MUSCLES, THE SKIN, By supplying them with By supplying them with By supplying it with bad blood. bad blood; bad blood; By loading them with By over-working the fat which makes them perspiratory pores. weak. * * * * * TO THE BLOOD, THE LUNGS, AND THE HEART. _TO THE BLOOD._--The wonderful fluid which is the life of the body consists of a water-like liquid in which floats millions of the very little, circle-shaped, red particles which you have been taught to call _corpuscles_. You have also been told that alcohol kills these little bodies, and thus takes some of the life out of the blood, and fills it with useless, suet-like fat. The blood, you know, flows everywhere through the body, giving its goodness to make every part grow and live, and carrying away the worn-out particles it meets. Blood, when poisoned with alcohol, goes through the body, giving disease and death instead of health and life. So, if you want good, red blood, do not let alcohol get into it. _TO THE HEART._--When alcohol comes with the blood from the liver, the heart begins to beat fast to get rid of the firewater; this makes it very tired, for it always has enough to do in carrying bad blood to the lungs, and pumping good blood into the arteries, without having the extra trouble of driving out alcohol. Wise people will not give it this extra work to do. Besides, we told you, in the talk about the harm done by alcohol to the muscles, that the heart,--which is only a large muscle, or rather many muscles fastened together so as to make a pear-shaped organ about the size of your fist,--is hurt in another way by alcohol. It gets too much of the poor kind of fat from the blood, which fills between the muscles, and after awhile makes the walls of the heart so soft and weak, that we could almost push through them with a finger, if we could get at them. Very often the tired, overworked, weakened heart suddenly stops beating, and the person who would keep on drinking beer, wine, brandy, or rum falls down dead. "Died from heart disease," people say, when the truth is, _died from drinking alcoholic liquors_. _TO THE LUNGS._--What are the lungs?--"The breathing-machines of the body." What do they throw out?--"Bad air." What do they take in?--"Fresh air." In pure air there is a good kind of gas which is necessary to keep us alive; this gas is called _oxygen_. When air is taken into the lungs, the oxygen mixes with the blood in them and makes it pure. If alcohol is in the lungs, it hardens the walls of their air-cells, and keeps out the oxygen or good gas; at the same time it keeps in the impure gas, called _nitrogen_, which ought to come out through the nose and mouth into the air. Thus the blood in the lungs cannot be properly purified, and goes back to the heart impure blood which is unfit to be used. The lungs are also obliged to work faster when alcohol is in them, because with the heart they are striving to drive out the enemy. This makes the lungs tired, sore, and inflamed. They are not as strong to do their work, and are more likely to breathe in any contagious disease than are the lungs of people who do not drink alcoholic liquors. Some people go on drinking these poisons for many years, and seem not to be hurt by them; but at last they suffer from what is called Alcoholic Phthisis, a kind of consumption which doctors cannot cure. HARM DONE BY ALCOHOL TO THE HEART. BLOOD-VESSELS. LUNGS. Overworks it. Hurries the blood through Makes them work too Makes it tired. them. fast. Loads it with fat. Stretches the small Heats and inflames Softens and destroys arteries and makes them them. it. unfit to work. Hardens the walls of Poisons the blood in the their air-cells. hair-like blood-vessels Keeps in the poisonous (capillaries). gas. Keeps out the good gas (oxygen). Weakens them and makes them diseased. * * * * * THE BLOOD ("The life ... is in the blood") Consists of A colorless liquid (plasma), and Little, red, circle-shaped bodies (corpuscles). * * * * * ALCOHOL (a blood-poison) Mixes with the colorless liquid, and takes away some of its goodness. Makes some of the corpuscles Smaller. Change shape. Lose color. Lose oxygen. Die, and change into useless fat * * * * * TO THE BRAIN AND NERVES. Where is your brain?--"In my skull." What color is it?--"Gray and white." What does it resemble?--"Marrow." What work is done in the brain?--"The work of thinking." You may repeat what you have learned about the membranes of the brain. (See Formula for the Lesson on the Nervous System.) You say "the inner membrane is a net-work of blood-vessels." If these are blood-vessels in the membranes, what fills them?--"Blood." Do you think alcohol can get into the brain?--"Yes." How can it get there?--"It goes there with the blood." How can we know that alcohol does mischief in the brain? You cannot answer? Did you never see a drunken man? Now tell me how you might know his brain has been hurt by alcohol.--"He talks funny; he acts strangely; he is very cross; he does not know what he is doing; he walks crookedly; he falls down; sometimes he falls asleep, and is almost like a dead man; he is dead drunk." Let us study to learn why the drunken man does such strange things. The alcohol in this bottle, and this egg which you see, will help us find the cause of the mischief. You may tell what is in the egg.--"A white liquid and a yellow liquid." How could they be made hard?--"By making the egg hot; by boiling." We will try what alcohol will do to the white part. You see when it is poured upon the white of the egg it hardens this part as boiling would harden it. This white portion is composed of water and something called _albumen_. The alcohol dries up the water and thickens the albumen. Albumen is found not only in eggs but in some seeds, as beans, peas, corn, etc., also in the gray part of the brain and in the nerves. We will talk first of the harm alcohol does to the nerves. You know they are the grayish-white cords which pass from the brain and the spine to every part of the body. What do they act like in the kind of work they do?--"Like telegraph wires." What is their work?--"To carry messages to and from the brain." What kinds of nerves have you learned about?--"Nerves of feeling and nerves of motion." When alcohol touches a nerve, it draws away the moisture or water from it, and hardens the white part or albumen; this makes the nerve shrivel as if it had been burned; it loses its power to feel and move, or, to use a long word, is _paralyzed_. Alcohol paralyzes all the nerves it touches. It makes them so stupid that they cannot understand what the brain says to them, and they do not carry the right messages back to it. For instance: when the nerves of the stomach are poisoned by the alcohol in beer, wine, etc., they do not feel the pain of hunger as much as they otherwise would, and they let the brain think the stomach is satisfied and does not need any more food, when it is only stupefied by these liquors. Again, it is the work of some nerves to tell the muscles of the small arteries to tighten, or contract, when too much blood is coming into them. Alcohol so paralyzes these nerves that they do not carry their message; the arteries let in the blood, and become swollen and enlarged. They tell the mischief done to them, by causing the skin to be red or flushed. If people drink much of any intoxicating liquor, and often, their skin is always a bad color, or, as grown folks say, becomes permanently discolored. All this because the nerves have been made unfit to do their duty by alcohol poison. The nerves also lose power over the muscles of the limbs. This is plainly seen in the trembling of the hands and the unsteady walking of the drunkard; but is equally true of those who drink only a little now and then. Their nerves are not as strong and wide-awake to control the machinery of the body as they would be if no alcohol were troubling them. Sometimes the nerves of hearing and sight tell the brain queer stories, and the poor brain believes them all, for it, too, is stupefied by the same fire-water which has hurt the nerves. Indeed, the harm done by alcohol to the brain is greater than that done to any other part of the body. It takes the water from the albumen, and makes the white part of the brain hard, as if it had been cooked. It kills the little, circle-shaped, red parts of the blood--the corpuscles; these collect in the blood-vessels of the brain, and keep the blood from flowing as fast as it ought, which causes disease and very often death. Sometimes the brain is so much injured by the poison that the drinker becomes crazy, and is a great deal of trouble to himself and everybody else. Since all this is true, wise children will let cider, lager, ale, wine, and every other kind of alcoholic drink alone, and never, NEVER, "Put an enemy into their mouths, To steal away their brains." * * * * * HARM DONE BY ALCOHOL TO THE NERVES. BRAIN. Takes away their moisture, and Fills or congests its paralyzes them. blood-vessels with impure Takes away their power to blood. control the muscles. Collects in it, and paralyzes Makes them unfit to carry it. messages to and from the Hardens its albumen. brain. So hurts it as to cause craziness (insanity) and death. * * * * * MORE ABOUT THE HARM DONE BY ALCOHOL. In the lessons you have learned you have been taught about the harm done by alcohol to the body and the mind; can you tell, from what you have seen of drunken people, in what other way alcoholic liquors hurt them?--"They make people waste their money; they make them waste their time; they make them cross; they make them fight; they make them say silly and wicked words; they sometimes make fathers and mothers hurt their children; they make people lose their good name; they often make them do things for which they are sent to prison." Yes, this is only some of the mischief done by alcohol. If you could fly around the world and see everybody who has been hurt in any way by this terrible poison, what a sad, sad sight you would behold! At least half the trouble in the world comes from strong drink. Are _you_, little girl, little boy, going to join the army of drunkards? No, indeed! you think; but probably no one who has become a drunkard ever intended to do so. They all began with one glass, a few drops of some alcoholic liquor,--cider, wine, or beer perhaps,--and thus learned to love the taste of alcohol, and soon became its slaves. For this poison has the strange power of making those who drink it want more and more of itself, though they know it is doing them harm. The only safety is in letting alcoholic liquors alone, forever. BLACKBOARD OUTLINE. ALCOHOLIC LIQUORS HURT The body, The mind, and The soul; AND MAKE PEOPLE WASTE LOSE UNFIT TO UNFIT TO SERVE Money, Strength, Think, or Themselves, Talents, and Health, and Work. Their neighbor, Time. Good name. or GOD. * * * * * STORIES ABOUT THE HARM DONE BY ALCOHOL.[6] A YOUNG BEGINNER.--The hardest drinker I ever knew commenced on cider when he was only five years old. He would go to the barrel of cider in the cellar, which had been put there to make vinegar, and, getting a straw, would suck all the cider he wanted; and then, after he had played awhile, he would go back and get more. He kept on drinking alcoholic liquors of some kind, until he died a drunkard. CIDER DELIRIUM.--Dr. J.H. Travis, of Masonville, N.Y., was once called to a child six years old, who was raving in the wildest delirium. His symptoms were so peculiar that he questioned the family closely, and found that the day previous, at a raising, the child had drank freely of cider. After the men left he had procured a straw and gone to the barrel and drank till he was senseless, and after this the delirium came on. He exhibited undoubted symptoms of delirium tremens. Cider was the common beverage of the family. Dr. Travis has been called to several other cases of delirium tremens from the use of cider.--_Mrs. E.J. Richmond._ A CAUTION TO MOTHERS.--One of the first literary men in the United States said to a temperance lecturer: "There is one thing which I wish you to do everywhere; entreat every mother never to give a drop of strong drink to a child. I have had to fight as for my life all my days to keep from dying a drunkard, because I was fed with spirits when a child. I thus acquired an appetite for it. My brother, poor fellow, died a drunkard." A GIRL DRUNKARD.--A young girl of eighteen, beautiful, intelligent, and temperate, the pride of her home, was recommended to take a little gin for some chronic ailment. She took it; it soothed the pain; she kept on taking it; it created an artificial appetite, and in four years she died a drunkard.--_Medical Temperance Journal._ "A LITTLE WON'T HURT HIM."--I was the pet of the family. Before I could well walk I was treated to the sweet from the bottom of my father's glass. My dear mother would gently chide with him, "Don't, John, it will do him harm." To this he would smilingly reply, "This little sup won't hurt him." When I became a school-boy I was ill at times, and my mother would pour for me a glass of wine from the decanter. At first I did not like it; but, as I was told that it would make me strong, I got to like it. When I became an apprentice, I reasoned thus: "My parents told me that these drinks are good, and I cannot get them except at the public-house." Step by step I fell.... I have grown to manhood, but my course of intemperance has added sin to sin. My days are now nearly ended. Hope for the future I have none.--_Dying Drunkard._ DANGER.--In one of Mr. Moody's temperance prayer meetings at Chicago, a reformed man attributed a former relapse of drunkenness wholly to a physician's prescription to take whiskey three times a day! KILLED BY THE POISON.--Many years ago, when stage coaches were in use in England, during a very cold night, a young woman mounted the coach. A respectable tradesman sitting there asked her what induced her to travel on such a night, when she replied that she was going to the bedside of her mother, of whose illness she had just heard. She was soon wrapped in such coats, etc., as the passengers could spare, and when they stopped the tradesman procured her some brandy. She declined it at first, saying she had never drank spirits in her life. But he said, "Drink it down; it won't hurt you on such a bitter night." This was done repeatedly, until the poor girl fell fast asleep, and when they arrived in London she could not be roused. She was stiff and cold in death, and the doctor, on the coroner's inquest, said that she had been killed by the brandy.--_Mrs. Balfour._ IN CASE OF SHIPWRECK.--In the winter of 1796 a vessel was wrecked on an island of the Massachusetts coast, and five persons on board determined to swim ashore. Four of them drank freely of spirits to keep up their strength, but the fifth would drink none. One was drowned, and all that drank spirits failed and stopped, and froze one after another, the man that drank none being the only one that reached the house at some distance from, the shore, and he lived many years after that. IT EXHAUSTS STRENGTH.--Concerning one cold winter when there were very severe snow-storms in the Highlands of Scotland, James Hogg, the poet, says: "It was a received opinion all over the country that sundry lives were lost, and a great many more endangered, by the administration of ardent spirits to the sufferers _while in a state of exhaustion_. A little bread and sweet milk, or even bread and cold water, proved a much safer restorative in the fields. Some who took a glass of spirits that night never spoke another word, even though they were continuing to walk and converse when their friends joined them. One woman found her husband lying in a state of insensibility; she had only sweet milk and oatmeal cake to give him, but with these she succeeded in getting him home and saving him."--_Bacchus._ SHIPMASTER OF THE KEDRON.--"I was brought up in a temperance school, and when I shipped before the mast I stuck to my principles, though everyone else on board drank excepting two boys whom I persuaded to abstain. In a very severe storm off a lee-shore, when it was so cold they had to break the icicles off the ropes to tack the ship, all drank but myself and these two boys. The men would work very well for a few minutes, and then slack off and take another drink, until they were all keeled up, and we three boys had all we could do to keep the ship from going ashore. If we had drank with the rest, all would have been lost, for the men were too drunk to save themselves. Providentially, the storm abated before morning, and we were saved. Now, for many years I have been captain of my own ship, and I never give out one drop of liquor."--_Captain Brown._ ON THE PLAINS.--Twenty-six men, travelling on one of the great Western plains in the United States, were overtaken by cold and night. They had food, clothing, and whiskey, but no fire. They were warned not to drink whiskey or they would freeze. Three did not drink a drop, and though they felt cold they did not suffer nor freeze. Three more drank a little, and though they suffered much they did not freeze. Seven others that drank a good deal had their toes and fingers frozen. Six that drank pretty strong were badly frozen and never got over it. Four that got very boozy were frozen so badly that they died three or four weeks afterward. Three that got dead drunk were stiff dead by daylight. They all suffered just in proportion to the amount of whiskey they took. They were all strong men, and had about the same amount of clothing and blankets; the whiskey was all that made the difference. THE RED RIVER EXPEDITION in Canada, in 1870, is often quoted as one of the most laborious on record, 1200 troops travelling 1200 miles through a very dense wilderness, and having all their supplies to carry. They were ninety-four days out, and none of them had liquor. They were constantly wet through, sometimes for days together, and all the while at the severe labor of rowing, poling, tracking, and portaging, yet they were always well and cheery, and there was a total absence of crime. IN AFRICA it is far safer to do without intoxicating drink. Livingstone says that he lived without it for twenty years. Stanley performed his wonderful journey without it. Bruce said more than one hundred, years ago: "I laid down as a positive rule of health that spirits and all fermented liquors should be regarded as poisonous. Spring, or running water, if you can find it, is to be your only drink." WATERTON, the great naturalist, who travelled so much in South America, says: "I eat moderately, and never drink wine, spirits, or any fermented liquors in any climate. This abstemiousness has proved a faithful friend." He died by accident at the age of eighty-three. MR. HUBER, who saw 2160 perish of cholera in twenty-five days in one town in Russia, says that "Persons given to drinking are swept away like flies. In Tiflis, containing 20,000 inhabitants, every drunkard has fallen." Of 204 cases of cholera in the Park Hospital, New York, there were but six temperate persons, and these recovered. In Albany, where cholera prevailed with severe mortality for several weeks, only two of the 5000 members of temperance societies became its victims. In Montreal, where the victims of the disease were intemperate, it usually cut them off. In Great Britain, those who have been addicted to spirituous liquors and irregular habits have been the greatest sufferers from cholera. In some towns the drunkards are all dead.--_Bacchus._ MALT LIQUORS, under which title are included all kinds of porters and ales, produce the worst species of drunkenness. The effects of malt liquors are more stupefying than those of ardent spirits, and less easily removed. In a short time they render dull and sluggish the gayest disposition.--_Anatomy of Drunkenness._ GINGER-BEER.--A man who has been a temperance-worker for forty-five years, says that there is often alcohol in ginger-beer. He told of a case known to him of a reformed man who, after drinking some, felt strongly drawn to the bar-room, where he drank until he brought on delirium tremens. The beer will sometimes ferment enough in a few hours to produce alcohol--if it answers the conditions--a sweet liquid and a ferment. DANGER TO THE REFORMED.--A lady who had become a drunkard through taking alcoholic drinks as medicines, at length, after many efforts, succeeded in breaking away from the power of the appetite, and for a long time she seemed to be saved. At length she went to visit her mother, and that mother put brandy peaches on the table for tea. They aroused the slumbering appetite, the victim fell again, became worse than ever, and died a miserable drunkard. [6] From _Juvenile Temperance Manual_, by Julia Colman. * * * * * STORIES ABOUT THE RIGHT WAY TO TREAT ALE, BEER, Etc. THE RIGHT SIDE.--"Boys, which is the right side of the public house? Can you tell me?"--"Yes, sir, the outside." THE GOAT AND THE ALE.--Many years ago, when everybody drank freely, a Welsh minister named Rees Pritchard was at the ale-house drinking, when he took it into his head to offer some ale to a large tame goat. The animal drank till he fell down drunk, and the minister drank on till he was carried home drunk. The next day he was sick all day, but on the third day he went again to the ale-house, and began to drink. The goat was there, and he offered him more ale, but the animal would not touch it. The minister, seeing the animal wiser than himself, was ashamed, and gave up drinking, and became a worthy minister. HOW THE MONKEY WAS CURED.--A monkey named Kees had been taught to drink brandy. At dinner every day he had his share like his more manly (?) neighbors, only that his was given to him in a plate. One day, as he was about to drink it, his master set it on fire, and he ran off frightened and chattering. No inducement could afterward make him drink brandy. We have many stories of animals who would never drink again after they had once experienced its effects. THE KEEN MARKSMAN does not poison his nerves and brain with alcohol. Angus Cameron, a Highlander, at the age of twenty, took the Queen's prize for the best marksmanship, and when he was twenty-two (in 1869), he won in the same way a cup worth $1000. He made the best shot each time that ever had been made in the contest, and neither of them has been beaten by anyone else. Angus is a slight, modest, unassuming young man, who had been a Band of Hope boy. When he was announced as the winner, and all the friends made an ado over him, and offered him a generous glass of champagne, he quietly refused their mistaken kindness, and kept his pledge. BENJAMIN FRANKLIN, when a printer boy in London, would drink no beer, and his companions called him the water American, and wondered that he was stronger than they who drank beer. His companion at the press drank six pints of beer every day, and had it to pay for. He was not only saved the expense, but he was stronger than they, and better off in every way. If he had gone to drinking beer at that time, like the other printer boys, it is likely we should never have heard of him. OATMEAL DRINK.--"In Boulton and Watts' factory we saw an immense workman at the hottest and heaviest work, wielding a ponderous hammer, and asked him what liquor he drank. He replied by pointing to an immense vessel filled with water and oatmeal, to which the men went and drank as much as they liked." This is made by adding one pound fine oatmeal to each gallon of water, and is much used in factories and at heavy work of all kinds in Government works, instead of the old rations of alcoholic liquors. Iron puddlers, glass blowers, and athletic trainers, all do their work now better without alcoholic liquors. A CHANGE IN AFFAIRS.--A poor boy was once put as an apprentice to a mechanic; and, as he was the youngest, he was obliged to go for beer for the older apprentices, though he never drank it. In vain they teased and taunted him to induce him to drink; he never touched it. Now there is a great change. Every one of those older apprentices became a drunkard, while this temperance boy has become a master, and has more than a hundred men in his employ. So much for total abstinence. BOOKS BETTER THAN BEER.--An intelligent young mechanic stood up in a temperance meeting and said: "I have a rich treat every night among my books. I saved my beer money and spent it in books. They cost me, with my book-case, nearly $100. They furnish enjoyment for my winter evenings, and have enabled me, by God's blessing, to gain much useful knowledge, such as pots and pipes could never have given me." A LITTLE DRUMMER-BOY was a favorite among the officers, who one day offered him a glass of strong drink. He refused it, saying that he was a Cadet of Temperance. They accused him of being afraid; but that did not move him. Then the major commanded him to drink, saying: "You know it is death to disobey orders." The little fellow stood up at his full height, and fixing his clear blue eyes on the face of the officer, he said: "When I entered the army I promised my mother on bended knees that, by the help of God, I would not taste a drop of rum, and I mean to keep my promise. I am sorry to disobey orders, sir, but I would rather suffer than disgrace my mother, and break my temperance pledge." He was excused from drinking. * * * * * TOBACCO. INTRODUCTORY LESSON. You have been learning about the poison alcohol, and what mischief is done by it; we will now study about another poison which thousands of persons are using every day. It is rolled in cigars and cigarettes, and hidden in snuff and pieces of tobacco, and does more harm to children and young people who use these things than to grown persons. Perhaps you know how a person feels who takes tobacco or smokes a cigar for the first time; if not, we will tell you. He begins to be dizzy, to tremble, to become faint, and to vomit; his head aches, and he is so sick for hours, often for several days, that he scarcely knows what to do. Why is he so sick? Because tobacco poison has been taken into his lungs; also, some has mixed with the saliva and gone down into his stomach; and each part it has reached is striving to drive it out, and is saying, by the pain it causes, "You have given me poison; do not give me any more." If he had taken enough it would have killed him. He recovers from this sickness and tries chewing or smoking again and again, until he becomes accustomed to the poison and can chew or smoke and it does not hurt him; so he thinks, but he is very much mistaken. Tobacco is a poison, and hurts everybody who uses it every time they do so, although it does its evil work very slowly, unless taken in large quantities. To understand more about this we will try to learn how tobacco is obtained, what poison is in it, and in what way it harms people. * * * * * THE STORY ABOUT TOBACCO. _HOW IT CAME TO BE USED._--Tobacco is the leaves of the tobacco plant, a native of America. It was used by the Indians of this country before Columbus came here in 1492. Some of the Spaniards who were with him on his second visit took some of it back with them to Portugal, and told the people they had discovered a wonderful medicine. From Spain tobacco seed was sent to France by Jean Nicot, in 1560. It is said that Sir Walter Raleigh carried it to England in 1586, when Elizabeth was queen. In a few years many civilized people were snuffing, chewing, and smoking tobacco, like the wild Indians, although it cost them a great deal of money to do so. King James does not seem to have liked it very much, for he said, "It is a custome loathsome to the eye, hateful to the nose, harmful to the brain, and dangerous to the lungs." He called the smoke "stinking fumes." _THE TOBACCO PLANT._ This plant belongs to the same family as the deadly nightshade, henbane, belladonna, thorn-apple, Jerusalem cherry, potato, tomato, egg-plant, cayenne pepper, bitter-sweet, and petunia. Most of the plants of this Nightshade family have more or less poison in their leaves or fruit. Tobacco is supposed to have been named from the pipe used by the Indians in smoking its leaves. The common tobacco plant grows from three to six feet high, and has large, almost lance-shaped, leaves growing down the stems; its flowers are funnel-shaped and of a purplish color. When fresh the leaves have very little odor or taste. _HOW TOBACCO IS USED._--When the plants are ripe, they are cut off above the roots and placed where they will become dry, sometimes in a building made for this purpose, called "a tobacco house." After a short time they begin to smell strong and taste bitter. They are then stripped from the stems very carefully and sorted. The leaves nearest the root are considered the poorest, those at the top generally the best. The different sorts are packed in separate hogsheads, and sent away to be sold to manufacturers of cigars, snuff, etc. The manufacturer has some leaves rolled into cigars, some pressed into cakes for chewing, or into little pieces to be smoked in a pipe; while some are ground for snuff. While the dried leaves are being rolled, pressed, or ground, various substances are mixed with them to give them an agreeable odor and pleasant taste. Yet, however pleasant the manufacturer may make them as he rolls, presses, or grinds, he cannot take the poison out of them. It remains in its brown covering to do much harm to those who may smoke the cigars, use the snuff, or chew the tobacco. BLACKBOARD OUTLINE. THE TOBACCO PLANT. NATIVE OF FOUND BY TAKEN TO GROWS IN THE America. Columbus, 1492. Portugal, Torrid and 1496. temperate zones. France, 1560. (About 50 species.) England, 1586. DESCRIPTION. FAMILY _Height_, 3 to 6 feet. _The same as the_ Jerusalem Cherry, _Leaves,_ lance-ovate, and running Petunia, down the stem. Potato, _Stem,_ hairy and sticky. Tomato, _Flowers,_ funnel-shaped and Egg-plant, purplish. Red pepper, etc. HOW MADE READY FOR USE. (1) (2) Cut-off above the roots. Flavored and scented. Dried. Rolled for cigars. Stripped; sorted. Pressed for chewing. Packed, and sold to the Ground for snuff. manufacturers. * * * * * THE POISON IN TOBACCO AND THE HARM IT DOES. _THE POISON._--What is the poison in fermented liquors?--"Alcohol." In distilled liquors?--"Alcohol" True; and the strongest poison in tobacco is _nicotine_, named from the man who first sent it to France, Jean Nicot. Beside this it contains several others, some of which we shall tell you about when we make up our blackboard outline. Tobacco, like alcohol, is a narcotic; that is, it soothes pain and produces sleep. Alcohol acts first upon the nerves; tobacco upon the muscles, which it weakens and causes to tremble. It often causes palpitation of the heart. If the skin is scratched or punctured, and tobacco poison put into the wound, it will do the same harm as if it were taken into the stomach. Tobacco is so dangerous that physicians do not use it much as a medicine. _HARM DONE IN THE STOMACH._--You remember that after alcohol has been swallowed, the little mouths of the stomach take it up and carry it to the liver, which sends it with the blood to different parts of the body. Tobacco, as we have already told you, poisons more slowly. People do not swallow it purposely, yet some of it goes down, accidentally, into the stomach with the saliva, and makes trouble there, causing nausea and vomiting when taken for the first time. By and by the stomach seems to take the poison without being hurt, but it really suffers from dyspepsia or other diseases, and often loses its appetite for wholesome food. _HARM DONE IN THE MOUTH, THROAT, AND LUNGS._--The mouth takes in some of the poison through the pores of the membrane, or skin, which lines it; those who smoke, sometimes have what is called "smokers' sore throat"; besides this, the senses of taste and smell arc more or less injured by nicotine and the other poisons in tobacco. The fumes, or smoke, from the weed fills the air with poisonous vapor which irritates the lungs, not only of the smoker, but of all who are where they must breathe the same atmosphere. Lungs thus irritated are liable to become diseased. Cigarettes are still more injurious than cigars because of the smoke from their paper coverings; also, because from the way they are made, more of the tobacco poison goes into the lungs. The cheap cigarette which boys use is made from cast-away cigar stumps and other filthy things. _HARM DONE IN THE BRAIN AND NERVES._--The smoker feels so rested and comfortable, after his cigar, and his brain is so rested, that he does not think about the mischief that is going on among its blood-vessels and nerves; perhaps he has never heard that tobacco, snuffed, chewed, or smoked hurts the brain, and does not learn about it until he finds he is losing his memory, that his mind is not so strong to think as it should be, and his will too weak to help him conquer his love for the snuff, tobacco, or cigar, when he wishes to stop using it. He has become the slave of tobacco, and it is not easy to get free from his cruel enemy. The nerves also lose their power, or become more or less paralyzed by nicotine and the other tobacco poisons. _MORE ABOUT THE HARM DONE BY TOBACCO._--Some persons who continue to use tobacco are strong enough to throw off the poison through the lungs, the skin, and in other ways; but how much better it would be if they were not obliged to employ their strength in getting rid of that which does them no good, which only gives a little pleasure to nobody but themselves, and often makes those suffer who are compelled to remain where they are having "a good smoke." Beside, their breath and clothing have the tobacco odor, which not only makes the air impure, but is disagreeable to most people. If this be true of smoking, what shall we say about the filthy habit of chewing, and the utterly useless and disgusting practice of taking snuff, which injures the voice as well as the senses of taste and smell? And what about spitting tobacco juice on the floors of cars, steamboats, churches,--any place where it is convenient for the man or boy who has lost his common politeness in his love for tobacco? We must not forget that cigars, etc., cost money. No one who smokes, chews, or snuffs would throw away dollars and cents which might be put into the savings bank, or used in buying something worth having for himself or somebody else. Lastly, we would have you know that tobacco causes thirst, and this often leads to drinking alcoholic liquors. Some one who has studied this subject, says that "nine out of ten of the boys and young men who become drunkards have first learned to smoke or chew tobacco." A New York daily paper gave a list of 294 cases of insanity caused by drinking, in 246 of which the whiskey drinking followed tobacco chewing. Tobacco and alcohol make thousands of wretched homes, and send a great many people to prison or to the insane asylum; so we entreat you to turn from beer, wine, and all alcoholic liquors as you would from a serpent, and say No, when tempted to smoke a cigar or use tobacco in any form. Do this all the more decidedly because, as we have told you before, alcohol and tobacco hurt children and young persons in every way more than they injure any one else. If you have begun to use these poisons, give them up this very day, before the habit of using them becomes too strong for you to break. * * * * * QUESTIONS ON THE USE OF TOBACCO. Of what poison beside alcohol have you been studying?--"Tobacco." How is tobacco used?--"Some take it in snuff; some chew it; some smoke it in a pipe; some smoke it in cigars or cigarettes." What is the name of the strongest poison in tobacco?--"Nicotine." What harm does tobacco poison do to the body?--See Blackboard Outline. What harm does it do to the mind?--See Blackboard Outline. Whom does it harm most?--"Those who begin to use it when they are children or very young." What happens to children or young people if they use tobacco in any way?--"They are not healthy; they are not strong; they do not grow fast; they look pale and sickly." How does the tobacco poison hurt their minds?--"They cannot learn fast; they often forget what they have learned." What often makes tobacco-chewers, snuffers, and smokers disagreeable to clean people?--"Their breath smells of tobacco; their clothes smell of tobacco; they poison the air with tobacco-fumes; some have the filthy habit of spitting tobacco-juice wherever they happen to be." What other harm does the use of tobacco do to people?--"It makes them waste time and money; it leads some to drink alcoholic liquors and to go with bad company." If you are wise how will you treat tobacco?--"I will let it alone." If you have begun to use it what had you better do?--"Give it up to-day." Why to-day?--"Because the longer I use it the harder it will be for me to give it up." If you keep on using it what will you be?--"A tobacco slave." * * * * * BLACKBOARD OUTLINE. TOBACCO. POISONS IN TOBACCO SMOKE. EFFECTS OF THE POISONS. Carbonic acid Causes sleepiness and headache. Carbonic oxide Causes trembling of the muscles and heart. Ammonia Bites the tongue; makes too much work for the salivary glands. Nicotine See below. NICOTINE IS CAUSES Odorous, Weakness, Pungent, Nervousness, Emetic, Dizziness, Poisonous, Nausea, Pain-soothing, Faintness, Sleep-producing, _i.e._ Narcotic. Loss of strength, Stupor, _If taken in large quantities_ Convulsions and Death. SOME OF THE HARM DONE BY TOBACCO TO THE BODY. TO THE MIND, ETC. Poisons the saliva. Makes the memory poor. Injures the sense of smell, taste, Lessens the power to think. sight, and hearing. Weakens the will. Causes "smokers' sore-throat." Makes people grow in selfishness Injures the stomach, causing and impoliteness. dyspepsia, etc. Makes people waste time and Often takes away the appetite for money. wholesome food. Often leads to drunkenness and bad Irritates the air-cells of the company. lungs. Sometimes causes insanity. Causes palpitation of the heart. Weakens the muscles, causing trembling. Injures the eyes. Excites, then stupefies and paralyzes the brain and the nerves. * * * * * OPIUM AND OTHER NARCOTICS. _OPIUM._--Opium is the juice obtained from the seed-vessels of the white poppy before they are ripe; this is dried, and smoked in a pipe or chewed. It makes a person feel very pleasant and happy for a little while, then so horribly wretched that he takes more of the poison to forget his misery. So he keeps on until mind and body are a complete wreck. Now and then an opium slave gets free from the dreadful habit which has mastered him, but usually the slavery ends only in death. _LAUDANUM AND MORPHINE._--These soothe pain and cause sleep; but beware of them; they are made from opium, and like it, though more slowly, hurt mind and body. Beware also of _chloral hydrate_ and _chloroform_, which physicians give to ease suffering and produce sleep. _Endure pain_ rather than form the habit of using these narcotics. _HASHISH, ETC._--This is prepared from the hemp plant growing in hot countries, and is a terribly exciting poison. The _areca nut_, the seed from a kind of palm, pear-shaped, and resembling a nutmeg, is mixed with quick-lime and wrapped in a betel-leaf, which grows on a vine belonging to the pepper family. This mixture reddens the saliva and lips, and blackens the teeth. It is chewed by millions of people in India. The leaves of the _coca_, also of the _thorn apple_, are smoked or chewed by the South American Indian. ALL these poisons mean the same thing,-- _A little pleasure_, DISEASE, and DEATH. * * * * * Practical Work in the School-Room. BY SARAH F. BUCKELEW & MARGARET W. LEWIS. Part I.--THE HUMAN BODY. TEACHERS' EDITION. A TRANSCRIPT OF LESSONS GIVEN IN THE PRIMARY DEPARTMENT OF GRAMMAR SCHOOL NO. 49, NEW YORK CITY. This work was prepared especially to aid Teachers in giving oral instructions in Physiology to Primary and Intermediate Classes. It is, perhaps, the only Physiology published that is suitable for these grades. Considerable attention is paid to the subject of Alcohol and Narcotics. "First is given _a model lesson_; second, _a formula_, embodying the principal facts given during the development and teaching; third, _questions for the formula_; fourth, _directions for teaching_; and fifth, _questions on the lesson_. These last are important. A full plan of lessons is given for each week for five months, in each of six grades, showing exactly how much work ought to be attempted. No book could be made more helpful to teachers. To the thousands who are asking, 'Tell us how to teach,' here are full, minute, and correct instructions. Even the answers expected are given, blackboard outlines are arranged, and nothing is wanting to make the book as useful to teachers as it is possible for any book to be. It ought to have a large sale. No book published during the last ten years will do more to drive away routine from the school-room and introduce thought than this, _if only the teachers will use it_. Its introduction displaces nothing but the old-fashioned monotonous recitations. Let them go; we welcome this book as an important aid in hastening along the good time of better teaching. It is excellently printed, with good paper and binding."--_The New York School Journal._ Illustrated. Price by mail, 75 cents. * * * * * DEVELOPMENT LESSONS. BY PROF. E.V. DEGRAFF & MISS M.K. SMITH. IN FIVE PARTS. I. FIFTY LESSONS ON THE SENSES, SIZE, FORM, PLACE, PLANTS, AND INSECTS. These lessons are presented objectively with a view to showing how elementary work in natural science may be done. II. QUINCY SCHOOL WORK. III. LECTURES ON THE SCIENCE AND ART OF TEACHING. Specific instruction is given on how to teach Reading, Spelling, Phonics, Language, Geography, Arithmetic, etc. IV. SCHOOL GOVERNMENT. V. "THE NEW DEPARTURE IN THE SCHOOLS OF QUINCY." By CHAS. FRANCIS ADAMS. DR. A.D. MAYO says, in the _New England Journal of Education_: "Although we have given place in our book-notice column to an appreciative mention of the volume, 'Development Lessons,' a new reading seems to call for a new commendation of this admirable guide to teachers. Mr. DeGraff needs no special 'boom' as a first-class institute man, and his extracts of lectures in Part III. sparkle with valuable suggestions. In no published work is Col. Parker really seen to such advantage as in the 'reports of conversations' with him in Part II., which can be studied with profit by every teacher. But perhaps the most complete portion of this admirable book is the 178 pages of lessons on the Senses, Size, Form, Place, Plants, and Insects, by MISS M.K. SMITH, now Teacher of Methods in the State Normal School at Peru, Neb." Handsomely Bound and Illustrated. 300 pages. Price by mail, $1.50. 
26280	----	+------------------------------------------+ | Transcriber's Note | |Spelling, punctuation and inconsistencies | |in the original book have been retained. | +------------------------------------------+ [Illustration: Book Cover] The Renewal of Life BY MISS MORLEY A SONG OF LIFE. 12mo $1.25 LIFE AND LOVE. 12mo 1.25 THE BEE PEOPLE. 12mo 1.25 THE HONEY-MAKERS. 12mo 1.25 LITTLE MITCHELL. 12mo 1.25 THE RENEWAL OF LIFE. 12mo 1.25 _Each fully illustrated_ A. C. McCLURG & CO. CHICAGO The Renewal of Life _How and When to Tell the Story to the Young_ By Margaret Warner Morley Author of "A Song of Life," "Life and Love," etc. Illustrated [Illustration: Publisher's Logo] Chicago A. C. McClurg & Co. 1906 COPYRIGHT BY A. C. McCLURG & CO. 1906 Published September 15, 1906 THE UNIVERSITY PRESS, CAMBRIDGE, U.S.A. Contents CHAPTER PAGE I. THE RENEWAL OF LIFE 9 II. WHO IS TO TELL THE STORY, AND WHEN IS IT TO BE TOLD? 17 III. HOW TO TELL THE STORY 27 IV. TELLING THE TRUTH 36 V. ON NATURE STUDY 40 VI. THE DEVELOPMENT OF THE SEED 52 VII. THE FERTILIZATION OF THE FLOWER 87 VIII. WHAT CAN BE LEARNED FROM THE LIFE OF THE FISH 107 IX. AMPHIBIOUS LIFE 127 X. THE BIRD 137 XI. THE MAMMAL 154 XII. VIGILANCE 169 XIII. THE TRANSFORMATION 178 LIST OF BOOKS HELPFUL IN STUDYING PLANT AND ANIMAL LIFE 193 _The Renewal of Life_ _How and When to Tell The Story to the Young_ I THE RENEWAL OF LIFE Every human being must sooner or later know the facts concerning the origin of his life on the earth. One of the most puzzling questions is how and when such information should be given to the young. There is nothing the parent more desires than that his child should have a high ideal in regard to the sex-life and that he should live in accordance with that ideal, yet nowhere is careful and systematic education so lacking as here. What parent would allow his child to go untaught in the particulars concerning truth-telling, honesty, cleanliness, and behavior, trusting that in some way the child would discover the facts necessary to the practice of these virtues and live accordingly? And yet with apparent inconsistency one of the prime virtues is neglected; one of the most vital needs of every human being--the understanding of his sex-nature--is too often left entirely to chance. Not only is the youth uninstructed, but no proper way of learning the truth is within his reach. It is as though he were set blindfold in the midst of dangerous pitfalls, with the admonition not to fall into any of them. Those who ought to tell the facts will not, consequently the facts must be gathered from chance sources which are too often bad, poisoning mind and heart. Even the physiologies, with the exception of those large, and to the average reader inaccessible, volumes used in medical schools, scarcely ever touch upon the subject. Of course these larger books give only the physiological facts couched in scientific terms. How and where, then, can the youth learn what he needs to know? It is true there is a noble effort being made for young men, and to a less extent for young women, by certain organizations that exist for the help of the young, to supply this curious defect in our educational system; but these efforts reach but comparatively few members in a community, and come too late in the life of the young to give them their first impressions on the subject. Perhaps the most encouraging sign for the future is the interest that thousands of mothers in all walks of life are to-day taking in the best methods of training their children to a right understanding and noble conception of sex-life. Innumerable mothers' clubs give the subject a place in the curriculum of the club work, at stated times discussing, reading, consulting all available authorities which may be of help. Some of these mothers live in poor homes in neighborhoods where their children are exposed to all sorts of evil communications and temptations. Others have sheltered homes, from which the children go out among refined associates from whom there may be little danger of learning that which is evil. Yet others live in moderate circumstances, where the home influences may be good, but where the children are liable to mingle with a heterogeneous society in their school and perhaps in their social life. Moreover, in all these homes there are children of different natures,--some with temperaments which make it easy for them to imbibe harmful information, while others as naturally resent such information. Nor is the child of rich parents living in a costly home necessarily the child least likely to make mistakes. The facts quickly refute any such idea. It is the child most carefully trained at home, with the most inspiring counsel and the wisest guidance in all directions, who has the best chance for successful living, the child whose parents not only secure the best outside assistance where such is necessary, but who themselves take a vital and continuous interest in his education. Such parents, where the help of nurses and teachers is necessary in the home, see to it that these helpers are wholesome, high-minded companions for the growing minds put under their charge. The poorest child is the child of wealthy parents, who is turned over to hirelings, chosen more for their accent of a foreign tongue than for their knowledge of child life and of the laws which govern the growing mind and body. Such children not infrequently become as depraved as the most neglected and exposed child of the slums, later poisoning the minds or shocking the sensibilities of children in the schools they attend. One of the difficulties every mother has to encounter is the presence of undesirable companions in the school. The argument that a child coming from a sheltered home will not be influenced by such companions is only in part true. He may not be influenced, or, again, he may. Among older children, if the wrongdoer be dazzling in manner, looks, social position, or even in power to lavish money, he will acquire a certain ascendency over many of his companions, who, if not safeguarded against his allurements by a clear knowledge of the facts of life, may fall into his snares. How, then, can all these various situations be dealt with? How, how much, when, and where shall the youth be safeguarded against influences, misconceptions, and mistakes which may mar his whole after-life? These are the questions which in part this book endeavors to answer. The answers come from the writer's experience of many years' work with mothers interested in this subject, especially from the testimony and the questions of thousands of such mothers in all walks of life who possessed children of all temperaments. The book is not meant to be either exhaustive or arbitrary. It is written with the single desire of helping the mother who may be groping her way in this matter, its aim being twofold,--to indicate methods of procedure among which the mother may find one adapted to her special needs and circumstances, or at least from which she may get hints which she can herself follow in her own way, and to indicate sources of information. One trivial difficulty has presented itself in preparing the succeeding chapters, and that is the lack in the English language of a pronoun including both genders. The English impersonal pronoun, being masculine in form, is liable to create the impression that "he" or "his" exclusive of "she" or "her" is the subject of discourse. This is not so. Generally the masculine pronoun is used impersonally in this discussion, and the discerning reader can easily decide from the context where this is not the case. As a help to the busy mother in selecting books for herself and her children, a list is given at the end of the book. This list is by no means exhaustive. There are many other and doubtless equally good books. The books given are reliable, are prettily illustrated, are now in print, and are easily obtainable at any book-store. If they are not in stock the book-seller will be glad to send for them. Further, to aid in selecting and ordering, the retail price is added. A small circulating library of well chosen books adds greatly to the usefulness of a mother's club, and such a library can be collected at small cost. Where the club is composed of heterogeneous members it is advisable that the president, or some member chosen for the purpose, should lead the discussion, which should be on some one topic selected and made known beforehand. This leader should not only guide the discussion, but be ready to explain the books and make the subject clear to those tired and overworked mothers who have had fewer educational advantages but who are in need of such knowledge as will enable them to guide their children. A mother unconnected with a club, and unable to afford all the books she wants, can find many of those here recommended in the village or city library; and where this is not the case the library is generally willing to make such purchases as its patrons request. II WHO IS TO TELL THE STORY, AND WHEN IS IT TO BE TOLD? Every thoughtful guardian of a child is sooner or later confronted with three questions in connection with this subject,-- Who is to tell the story to the child? When should it be told? How should it be told? _Who shall tell the story?_ The best teachers in this subject are undoubtedly the child's parents. Since the mother generally spends more time with him and is more accustomed to instruct him in manners and morals it naturally belongs to her to give him his first instruction here, and it is an opportunity which no mother understanding its value can afford to miss. Nothing draws a child so close to his mother as the knowledge, rightly conveyed, of how truly he is a part of her. Almost without exception the young boy learning the truth from the lips of his mother has a new feeling of reverence and love for her. Countless are the testimonies of mothers as to the result of telling this fact. One illustration will answer as an example of hundreds of similar ones. A certain little boy listened open-eyed to the story; then, the blood mounting to his cheeks, he threw himself into his mother's arms, exclaiming, "Oh, mamma, that is why I love you so!" Moreover, if the right kind of confidence is established between mother and child, the child will come to his mother with his questions and difficulties instead of trying to satisfy his curiosity elsewhere. The question is often asked, Will not close companionship and sympathy between mother and child in a general way produce the same result, causing the child to confide in the mother in case of needing information, without any previous talks on the subject? Of course the closer the relationship between the two the more easily will the child confide everything; yet with very many children, if this one subject is avoided (and particularly is this true as the child grows older), it will not be introduced by the child, no matter how much he may desire the knowledge, or how intimate in other ways may be his talks with his mother. The judicious mother can get a hold upon her son through this subject that nothing else gives; she can keep him closer to her, and oftentimes can guide him safely over difficult places. What is true of the son is of course true of the daughter. The little girl will respond as readily as her brother to confidences of this kind, and will find them as helpful. She very often escapes much that her brother in his freer life meets, yet undoubtedly in the great majority of cases the instruction is as vitally necessary to her as to him. While the earliest teachings seem to fall most naturally to the mother, the father should also share the responsibility and the privilege, talking with frank confidence upon the subject whenever occasion offers. The question is often asked, Is it not better for the father to talk to the boys, the mother to the girls? There no doubt are cases where this might be wise, but the mother, understanding the close relationship between her son and herself that may come through such talks,--a relationship continuing and increasing in value as the years go on,--would feel that she could not afford to lose anything so precious to both her boy and herself. While the establishment of this relationship might be difficult or even impossible later, it is easily begun in childhood and as easily continued. Moreover, many boys are specially helped by talking with their mother. They often feel in her a quicker sympathy and a more perfect understanding of their needs; and as their instinctive desire is to understand life from _her_ point of view as well, they often feel something in her which is lacking in the father. On the other hand, the boy who is talked to exclusively by the mother, particularly when he begins to develop into manhood may say, or think, "Oh, you cannot understand; you never were a man." The father's voice here is needed, but if that is impossible there is abundant written testimony and advice from well-known men to youth on this subject which can be put into the boy's hands. While the child's best teachers of these intimate truths are undoubtedly his parents, it may happen for various reasons that this is impossible. The child may have grown to an age where the timid parent, who has not hitherto realized the necessity, cannot approach him. Or there may be other reasons. In such cases the duty may devolve upon some one else capable of fulfilling it. Such a one may be, should be, the minister. It ought to be a part of the recognized duty of every minister of a congregation to see that such of his young men as desire it are instructed in the facts necessary to their well-being in this direction. It is not enough to tell them to live pure lives; they must be helped to understand their own organizations and everything pertaining to this side of life that they need or want to know. There should be similar help obtainable by the young women of the congregation from some competent woman approved by the minister. Purity is an integral part of the religion of the new civilization, and purity and everything helping to it should be as conscientiously and thoroughly taught in the churches as are any other religious truths. In the church the young man, the young woman, should be able to find corroboration of the sex-truths taught him by his parents; and those young people not so fortunate as to receive instruction at home should be able to drink from their religious teachers deep draughts from this spring of salvation. The family physician ought also to be a refuge of help for the young; and here the woman doctor, that blessing of these later days, can do a work of reformation and salvation. No one has more power to sow seeds of wisdom in the homes of the people, helping the mother to understand and desire the careful instruction of her children, and where the mother requests it, being ready to give the needed help to the young people themselves. Again, the teacher or some friend may be requested by the parent to come to the help of the needy child. But whoever gives this information, it is needless to say, should himself be pure in heart, of high moral principles, with a firm belief in the value and possibility of purity, and with sufficient knowledge of the subject in all its aspects to be a wise instructor, giving not only physiological information where that is desirable, but working specially for ethical and spiritual elevation. Physiological facts alone may not have the slightest effect upon the manner of living; there should be first and deeply implanted a spiritual desire for purity, when the knowledge of such facts may be a valuable help. The question is very often asked, Should this subject be taught in schools? To a certain extent it is taught. Every botany class teaches its rudiments; and in the higher grades, where biology is taught, the pupil comes to a clear understanding of the main facts. School botany, however, merely glimpses at the truth, and biological classes are few and far between. So, as far as the majority of children are concerned, the schools can hardly be said to touch the subject. Whether it would be well for the schools to deal with it is a very difficult question, so much depending upon the way the work is done. It might be possible to introduce it helpfully in connection with a well graded system of nature-study, but since such does not exist in most schools, and since there is very great danger in speaking in public on this subject before children, no matter how well the speaking may be done, it is undoubtedly better not to approach it directly in the schools,--at least in grades below the high school. Like religious training, this belongs peculiarly to the home and the parent. Although she cannot give general instruction, the teacher of children can help by being watchful of her flock, alert to detect signs of wrong doing, ready to help by private counsel, and--when parents consent--to give information to any needy child. In dealing with this subject the teacher needs to be as wise as the serpent and as harmless as the dove, not only for her own sake but for the sake of those she wishes to help. _When to tell the story._ It is an axiom of education that the foundations of knowledge should be laid in childhood. From all time it has been observed that what is learned in the earlier years remains most persistently through life. Hence we begin to inculcate moral truths at an early age. Ideas of truthfulness and honesty, for instance, are graven so deeply on the young mind that they can never afterwards be erased. "Just as the twig is bent the tree's inclined," said our forefathers, and it is true. "First impressions are the most lasting," is another true adage. This being so, we should see to it that the first impression the child gets on the subject in question is the one we wish him to keep. Many a life has been lamed and saddened because of the first terrible and ineradicable impressions it received upon this all-important subject. Many a high-minded man and woman have gone through life tormented by images of the first unworthy thoughts. No matter how good the after-knowledge may be, it is almost impossible to erase from the tablets of memory that old first impression. Of course it would be absurd to tell a young child most of the facts, just as it would be absurd to try to teach him the whole arithmetic in one school term. He could not understand, and, particularly in the case of the former subject, he would be harmed instead of helped. Just how and when to unfold the matter to his comprehension will be carefully considered as these pages progress. Here let it suffice to say that with the young child we may begin by building carefully block by block the foundation we want to use later; with the older one we must needs work faster, seeking to anticipate or counteract any unfortunate information from outside sources. Thus the age of the child and his surroundings will to an extent determine the time or times of telling the facts. III HOW TO TELL THE STORY This is the most difficult question to answer, and one that requires time. Indeed, one might say it cannot be answered excepting in a general way, and that any effort to tell the truth sacredly is better than not to tell it at all. Where the children are still young the task is comparatively simple when once begun. It develops naturally, with time for thought on the part of the teller; and the steps are easy and convincing. One of the questions most frequently asked is this: Does not talking about these things fix the child's mind unduly upon them? As a matter of experience it is just the other way. The child who has always known the facts is not curious. Why should he be? There is nothing to be curious about. It is all as much a matter of course to him as the rising of the sun. And he is safeguarded against a certain pruriency that comes from wrongly stimulated and vilely fed curiosity. Instead of causing the child to think more about the subject, the tendency of good teaching is to prevent his thinking of it. Another question frequently asked is, Does not talking on this subject arouse curiosity in children who otherwise would not be curious? The answer is that it does not arouse harmful curiosity. The right kind of curiosity on any subject is of course good. Indeed without the desire to question and investigate everything about him man would be yet a savage living in a hole in the ground, and the starting-point of all the child's after-knowledge is curiosity. There are two kinds of curiosity, a good kind and a bad kind. The good kind is interested in finding out things for the sake of understanding them; the bad kind serves a bad end,--in connection with this subject it leads to investigations which produce wrong thoughts and feelings, and is gratified for the sake of producing those thoughts and feelings. The same subject may give rise to either kind of curiosity, according as it is presented. To-day we take every pains to stimulate the curiosity of our children. We teach them to observe carefully the flowers, the insects, the animals,--everything about them. We cannot expect them to exercise their stimulated minds on all other subjects and turn blind eyes upon this one which is obviously so important and so interesting. No, the more they learn to look and ask about other things the more they will look and wish to ask about this. That children differ in curiosity is very true. Some children seem to have very little curiosity about anything. Yet such children are sent to school with as much care as are the children eager to know. A child might show no interest in books, might find the reading lesson irksome; but the mother would know he was learning to read for the use that reading would be to him later, not for the sake of the things in the reading-book. It is the same here, the child learns the facts for the sake of his future. There are good reasons which will appear later why every child should have the right information on this subject whether he seeks it or not. If he is indifferent, one can be sure the proper kind of information will not hurt him; if he is eager, one can be sure he ought to be carefully and thoroughly instructed. As a rule the most active and eager children and those with the quickest minds are the ones most curious to understand the origin of life, though there are exceptions. It is not legitimately gratified curiosity that harms, but suppressed curiosity, which in this subject is almost sure to result in the acquisition of wrong and often of perverting information. The surest way to arouse curiosity is to try to conceal something. The only thing, then, is to be ready to gratify honest curiosity by helpful information. Nor is it safe to defer too long. What the mother wants her child to know in a certain way she should tell him herself, before he has a chance to hear it elsewhere. The moment he leaves her presence, the moment he starts alone to school, he may receive information which she would give the world to prevent his receiving. Not that her telling will necessarily keep him from hearing what others say, but to have his mind preoccupied will tend to prevent the wrong ideas from taking firm root. * * * * * Another question very often asked is, Will teaching this subject not encourage children to talk about it with other children? On the contrary, the tendency is to prevent talk. The children of a family equally instructed will not find it worth talking about. They know what they want to know, and understand that the only person who can really tell them anything more is their mother, or whoever takes her place in this. If they do talk of it in the spirit in which they have been taught, such talk can do no harm, excepting in the presence of children not equally well instructed. To meet this danger the mother can take certain precautions. Having won the confidence of her child, she can generally trust him to keep these matters confidential with her. She can explain that children do not always know the truth about these things, and sometimes do not know about them at all. That some mothers do not tell their children, but that she wants her child to understand everything just as it is, and to feel that she can trust him not to talk on these matters excepting when alone with her. Of course there will be instances where this does not succeed, and the children eager and pure will speak in the presence of the neighbors' children and make trouble. Then the question is, Which is better, to run that risk and take the consequences, or to run the risk of allowing the child to remain ignorant? If the child could really remain ignorant, there might be room for argument against enlightening him, but there is great danger that he will be enlightened in a very unenlightened manner, and possibly by those same neighbors' children who are truly ignorant, though they may not be ignorant in just the way their fond parents believe them to be. Many people still confound ignorance with innocence, though these are by no means related. The most ignorant person in the world might be the least innocent, and the most innocent might very well be the most enlightened. It not infrequently happens that the very children whose mothers are most opposed to enlightenment on this subject are dangerous companions for good children. To guard against unprofitable or otherwise harmful teaching, the mother should instruct the child not to listen to talk on this subject and not to join in it, and at the same time tell him that in case he does hear anything that troubles him he should come to her and she will talk it over and explain, so that he may know what is right and what wrong. She should promise to tell him _the truth_ about whatever he may want to know. Having made this promise she must keep it. There is nothing more dangerous than to put a child off with evasive answers. He immediately jumps to the conclusion that there is some reason why his mother is afraid or ashamed to explain things to him, and if he has heard evil rumors it is quite natural for him to suspect that what he has heard is the truth and the whole truth, else why should his mother not help him? He soon feels ashamed to ask her questions which she refuses to answer, and he ceases to confide in her. There is nothing easier than to win and keep the confidence of a child, and often there is nothing more difficult than to regain it when once it is lost, particularly in this direction. It is a loss the mother can by no means afford to sustain. Mothers sometimes object that their young sons bring them the most shocking or absurd stories which they have heard in school or elsewhere. The mother who gives one moment's serious thought to such a situation will be forced to the conclusion that for her to hear such tales is nothing compared to the child's hearing them, and that his coming to his mother is proof of his own innocence. It is surely her first duty, no matter how difficult or unsavory the task, to sift out the wrong from the right, to show the child wherein the story is absurd, wicked, and harmful. At such a crisis the mother should be very careful not to show any offence because the child has brought her the story. She may condemn the story as severely as she likes, but she must be careful that the child does not feel himself included in the condemnation. She must also be careful in denying the story not to deny the germ of truth which it will contain, or the child may conclude that she is talking against the facts, and is either ignorant or trying to conceal the truth. Many a mother has said in despair, "My boy of nine knows more about these things than I know myself." It would be a great mistake to let the boy hear such a confession, as his very best safeguard is his confidence in the knowledge of his mother, or whoever assumes the duty of instructing him in these matters. IV TELLING THE TRUTH Should the mother tell pleasant but totally false stories as to the origin of the child,--or should she tell the truth? It is generally safer to tell the truth. Excepting with very young children the fiction is not long believed, and a course of deception, having been entered upon, oftentimes proves a stumbling block in the way of later veracity. It is so much easier to go on telling fairy-tales. Moreover, the truth, properly conveyed, is far more beautiful than any fairy-tale. The parent must not forget that the child's mind is a blank page upon which any picture may be drawn, and that the child sees only what is presented to him. The thousand problems, the thousand troubles and fears, and all the knowledge of evil that burden the mind of the adult are entirely absent from that of the child. He sees only the one shining fact, that he was once a part of his dear mother, nourished and protected by her until he was ready to open his eyes on the big world. The child has very little interest in details as a rule; and how to meet the demand for them, should it arise, will be considered later. If the mother tells the story of the stork bringing the newcomer to the home, or of the doctor carrying him in his pocket, or the apothecary selling him over the counter, the child very soon learns that this is not true. He gets an inkling of the truth, understands that he has been deceived, and according to his age, his nature, and what he has heard, he will draw his conclusions as to why his mother did not tell him the truth. Mothers often ask whether there is any more reason for refraining from the stork fiction than from the Santa Claus one. When Santa Claus is found out, the whole thing is generally understood as a joke, a pleasant sort of fairy tale. There was nothing hidden behind the fiction. In the other case, if the child chances somewhere to hear the facts stated in a coarse manner, he will be likely to feel instinctively that the new tale is the true one, and will naturally conclude that the pretty fable was told to conceal a most unsavory truth. His first impression of the real facts will in such a case be ugly and--in a deep sense--false. It will hurt his sensibilities, or arouse his lower nature, according to his temperament. The mother can guide herself by a rule which has exceptions but which in the main holds good: The child able to ask a question is able to understand the answer. This is by no means saying that all the facts should be stated at once. That would be absurd. The question asked should be answered as simply as possible, the parent remembering that children's questions are usually more profound to the hearer than to the asker. It is difficult for the adult not to read into the child's chance question all the profundity of his own years of experience, and the mother who approaches this subject with dread is almost invariably astonished and relieved to find how easily the child is satisfied. Where the child asks by chance or design (and it is a wise parent who can always decide which it is) a question beyond his comprehension, or one that the parent is not ready to answer, he can be put off temporarily with the promise to explain another time. The child may forget all about it. If not, then the promise must be kept; and the very fact that the child remembers shows that he is thinking, and therefore ought to be helped. If the child asks questions which the mother feels sure he is not ready to have answered, she can promise to tell him when he gets older, explaining that he could not understand now. In such cases, however, the mother should always manifest a willingness to tell him something; she should talk with him enough to make him feel sure she will keep her promise. He should never be allowed to forget that he can go to his mother as frankly as to his own heart, with the certainty of finding sympathy and aid. And she should not let him forget that he is not to seek information from outside sources, such information being unreliable. V ON NATURE STUDY Since the most beautiful and ideal way of presenting the facts of the renewal of life is through nature-study, a few words as to the handling of this interesting topic may be helpful to some mothers. In all nature-work with the child, the subjects treated should be made interesting and beautiful. This cannot be too strongly insisted upon. The child has a right to the pleasure, the elevation of sentiment, the play of imagination which the contemplation of nature is able to give in such a peculiar degree. He has a right to the romance of the flower, cloud, bird, fish, animal life, plant life, in all their ramifications. It is a part of his soul-development. Consequently, whatever is done for him should be done in such a way as not to hurt his sensibilities. His pleasure in nature should be increased, not lessened, as a result of his study. As his knowledge expands his interest should deepen. This will almost never be the case where the first instruction is purely technical. Nothing, for instance, has deadened the interest of children in plant life so much as the study of botany. This is because the school methods have been wrong, the work being almost always approached from the wrong end. It is because the learner's mind is dammed up by difficult and to him empty technical terms. As a consequence, the course of its flow in this direction is stopped, and instead of a clear stream leaping joyfully through the woods and meadows finally to reach the great goal of the boundless ocean, it resembles rather a motionless pond, the surface of which is covered with lifeless and unlovely debris. Naturally the child seeks to escape from this uninteresting and dead pool by turning his mental energies in other directions, and too often he loses interest forever, and with it the pleasure and the vast profit that might have come to him from a different conception of the subject. Facts about the life of the plant should be abundantly presented, and the facts as collected and told to-day are well-nigh inexhaustible as well as fascinating. True stories of plant life can be, and should be, as interesting as any other stories. Technical terms should be used at first with great restraint, and, as a rule, only where they are obviously convenient or of such universal application that they are a distinct help in developing a sense of the continuity of living things. Those that are used should be so skilfully introduced, and their meaning so thoroughly digested, that they do not seem like technical terms. Perhaps an illustration will make this point clearer. A child who loves flowers goes to school; he is given one of his favorites and told to pull it to pieces, look at its different parts, and label them with such words as petals, sepals, pistil, stamens; to these are presently added calyx, corolla, monopetalous, polypetalous, innate, adnate, indehiscent, etc., until the child's mind resembles a lumber room of senseless rubbish, in which the flower is buried and lost. To a sensitive child this process is exceedingly painful. He often feels as though he were murdering some helpless thing he had loved, and conceals his tears and his heartache for fear of being laughed at. Less sensitive children are soon wearied and disgusted, and the love for nature which might have been aroused in them, to the sweetening and steadying of their whole after-life, receives a fatal check. While the child's love for flowers, and his sentiment concerning them, should not be harmed by his plant work, on the other hand a certain tendency to weak sentimentality wherever encountered should be restrained. He should not be a mere receptacle for dry ashes nor yet a mush of sentimentality. The wise leader will discover the broad middle course where love of the flower shall be deepened, and, as it were, broadened, by knowledge of its wonderful structure and functions. These can be well understood without so much as one technical term, though the skilful introduction of a few helpful words will not detract at all from the pleasure of the study, and will be most convenient. [Illustration: THE ANEMONE OR WIND-FLOWER] Even the botanical names of the flowers themselves are of questionable value. The main thing is to recognize the flower as we recognize any other friend, and of course some name is necessary, but that this name be technical is, in most cases, not even desirable. "Wind-flower" is quite as good as "anemone," better, indeed, as it expresses a certain feeling about the flower that "anemone" does not convey. So, too, "mayflower" is more suggestive than "trailing arbutus," and that than _Epigæa repens_. Thus at first let the children learn only the common names of the flowers, at the same time that they discover all that is interesting about them. Later, when their interest is sure, the pretty name "anemone" will give an added charm. They can be told that it comes from the Greek word _anemos_, meaning wind, and that anemones grow in Greece, and all that part of the world, and are gathered by the little children there. If the children are of an age to be studying or reading the tales of mythology, or the fascinating beginnings of Greek and Roman history, they will be delighted to think that anemones were no doubt gathered by Ulysses and Hector and the other Trojan heroes when they were children in that far-away land, and that the grandson of �neas saw them in the Campagna near the Rome he founded, as the Italian children see them to-day. Thus through his botany the child can get a more vivid sense of the life of the past, can have a link forged in that invaluable mental chain which links him, mind, body, and soul, to everything else in the universe, and the consciousness of which is one of our most precious and helpful endowments in this life. The universality of life and mind and soul, the universality of the methods of their manifestations even, the unity of life,--nothing by itself, everything going out into and permeating everything else,--this great truth, which ought to burst upon the young mind with controlling force at a critical period later, should have its way prepared in childhood. So far as technical terms are concerned, the child will gladly take them--in small doses--when he understands the things they represent,--that is, when the knowledge comes before the label; and when he recognizes their convenience in grouping the different varieties and species so that their relations to themselves and to other plants can be kept in the mind with a minimum of exertion. [Illustration: WILD ROSE WITH BEES GATHERING HONEY] The time comes when the analysis of the flower can be as interesting as any part of the work, if it has been preceded by other information and if it is pursued intelligently and delightfully. To illustrate again. The wild rose looked at simply as a thing of beauty and perfume becomes yet more interesting to the child who watches the bee gather its golden pollen and its luscious nectar. There is a bond of union now between the fragile flower and its winged guest that begets an altruism which later becomes normally the corner-stone of character. When the graceful tribute of the bee to the flower is presently understood, and the child learns that the seeds of the flower have to thank the bee for their life, the mind expands yet more, and glows at the thought of this relationship in which each of these charming creatures practically preserves the life of the other. [Illustration: THE SEED, THE CHILD OF THE PLANT, IS AT THE HEART OF EVERY FLOWER] Now, too, the thought that the seed, the child of the plant, is at the heart of every flower, that it is for this nascent life, this new venture into the great world, that the blossom unfolds in beauty and sheds its perfume on the summer air, yet more expands the joyous interest taken in the blossom. The mind, through a knowledge of these facts, can leap out into wider spaces of feeling and imagination. Thus every truth the child learns about the rose in those first tender years ought to add to his poetic conception of it. Thus he should learn his rose until the time comes when its relation to certain other plants will be full of meaning and full of interest. Perhaps the child has studied the apple blossom, the strawberry flower, the peach blossom in this same delightful way. With a very little help he will recognize the similarity of all three to the rose. He will be delighted to know that these are as truly related as they seem to be, that they are indeed cousins in one charming family. How they came to be so different will be a natural question, the answer to which will involve the latest and most valuable scientific discoveries. Indeed, in studying nature we should begin with the latest discoveries of science, which are biological and vital, and end with man's earlier efforts toward knowledge,--that is, with classification and nomenclature. When the child knows his plants he may be interested in their relationships and willing to do the necessary drudgery toward establishing them. If not, it doesn't matter, he has the really vital part of the subject, the part that will best help him toward understanding all life, his own included. It is to foster a high sentiment toward the life of the plant that the numerous so-called unscientific botanies which crowd the book-stores to-day are so valuable, and the numbers that are sold testify to the interest this side of the subject awakens. What technical botany has anything like the sale of these less technical books? So far as the real development of the world at large is concerned they are of inestimably more use than the technical works, though of course those were the stern Puritan parents who have given rise to this flock of lovely non-puritanical children, and without which they of course could not have existed. The technical botanies indeed have their use to-day, and it can be confidently expected that they will be more used than ever before, because of the large numbers who have had their interest quickened and a desire to know more awakened. Those who would have found botany interesting in spite of the old methods will pursue it yet more eagerly under the new. Many who would have turned away from it entirely will continue their study into the technical works, while great numbers who have no leaning toward technical study and would have had nothing to do with botany under the old methods, under the new will assimilate the best truths the study of this subject is able to give, and so far from finding a wild rose less fragrant or less beautiful because of their close scrutiny of it, they will find it infinitely more so,--infinitely more rich in affording poetical thoughts, comparisons, and images. What is true of plant life is equally true of animal life. The first attention should be directed toward the animal itself, its life and habits, technical information coming afterwards. VI THE DEVELOPMENT OF THE SEED In dealing with the special subject of this book too much stress cannot be laid upon the value of associating the phenomena of the renewal of life with all other vital phenomena, instead of divorcing it from them. Two reasons why the subject of reproduction has such undue prominence in the minds of many people are, first, the manner in which it has been made conspicuous through concealment; and second, the fact that when spoken of at all, it has been treated as a unique phenomenon unrelated to anything else. These are not the only reasons, but they are strong ones, and their existence is quite unnecessary. Education, therefore, should remove both of these stumbling-blocks. The first one is easily removed, though the value of its removal depends entirely upon the manner in which that removal is accomplished. The second is also easily removed, the only difficulty being how to do it in the most helpful manner. The problem, then, for the instructor to solve is, how fully to acquaint the child with the phenomena of the reproductive life without making the subject unduly prominent. This can well be done by interesting him in all the phenomena of living things, and allowing the reproductive function to take its place, not as something alone and different from everything else, but as one in a series of vital phenomena, all equally important and all interesting; not as something peculiar to human life or to the higher animals, but belonging equally to every living thing, whether animal or plant, and manifesting itself in the same way everywhere. Nor is this as difficult as at first glance it may seem. Indeed it is not difficult at all if one can begin with the young child, building little by little the foundation upon which later to erect a noble superstructure. It is a beautiful fact that the plant world offers illustrations of all the underlying phenomena of the reproductive life, and that through the flowers the little one can get his first introduction to the great subject. Not that he will at first understand the connection between the flower life and the human life, but the facts in the flower having been clearly perceived, there is nothing easier or more beautiful than to expand the idea when the time comes, until it embraces all life. But what about those children who are no longer in their infancy? How are they to be taught? In practically the same way, with some modification of method. Since the aim here is to present the subject from the beginning, the first succeeding chapters will deal with it as applied to the young child. Following this, methods for use with older children will be discussed. * * * * * Objects to be accomplished with the younger children in the study of the plant. (1) To make them feel that the plants are living things with activities like other living things. (2) To convey a clear idea of the true relation of seed to plant. This can be amplified later to cover the reproductive phenomena of human life. (3) To give them a foundation for understanding the relation of father to child, when the time comes to explain that. * * * * * Some children naturally think of the plant as alive; they endow it with thought, feeling, and emotion; talk to it, consult it, caress it. Others do not. In both cases it is of value to the child to know the deeper truths concerning the life of the plant. In the one case it will steady sentimentality and guard against later loss of interest, in the other it will stimulate imagination and foster a high type of sentiment. An easy and effective way to begin the study of the plant is to watch it as it sprouts from the seed. Since a large seed, easy to see and simple in structure, is best, an ordinary bean answers the purpose admirably, particularly as the bean has the convenient habit of rising up above the ground when it sprouts, the development of the embryo proceeding in full view. Any of the common varieties will answer the purpose, though of course the larger the bean the more easily it can be observed. A child of three or four will be interested in watching a seed grow. The first season he may get only one idea, the seed grows into a plant. The next season the experiment may be repeated with as much of the story of the plant added as the little one can understand. Thus Spring after Spring the child plants his seeds and watches them grow, constantly adding to his store of knowledge about them, until the story of the plant and its seed is as familiar to him as any fairy-tale, and has gone into his consciousness to stay there forever. Let us examine the bean, then, and see what can be learned from it, the information thus obtained to be shared with the child as fast as his age and his power of understanding permit. [Illustration: THE BEAN, SPROUTING, TO SHOW THE TWO SEED-LEAVES AND THE EMBRYO] First let us examine the dry bean. It is hard, so hard that we can scarcely bite it. Put it to soak in tepid water, leaving it over night. Next day look at the changes that have taken place in it. The first thing we notice is that it has swollen until it is twice as large as it was, being now soaked full of water. It is also softer than it was. Its outer skin during the process of soaking has loosened, being no longer firmly attached to the body of the bean. This skin, being unable to stretch, soon splits open by the swelling of the bean inside. We can easily slip it entirely off. [Illustration: THE BEAN--EMBRYO-LEAVES, SEED-LEAVES, AND ROOT] Having done this let us take a good look at the bean that is now out of its skin. We see that it is composed of two thick parts which are joined together at only one end. These two thick parts which make the bulk of the bean are called seed-leaves (cotyledons). Just at the point where they seem to be joined together there is a tiny flat white object. Looking closely at this we discover it to be a plant consisting of two minute leaves and a little blunt tip. As a matter of fact, the two seed-leaves are not attached directly to each other, but each is attached to this tiny plant, or embryo, as it is called. The word "embryo" is a valuable one to use later, and its precise meaning can easily be fixed by always calling the young plant tucked away in the seed the embryo. The difficulty of learning new words does not lie in their length, but in not knowing what they mean. A child who has been to the circus has no trouble in remembering the word "elephant," and the child who frequently hears the word "embryo" spoken in connection with the plant concealed between the cotyledons quickly and unconsciously learns it. Place some of the soaked beans on damp cotton, and plant others in a pot of earth, or, if it is Summer, in the garden. Those sprouted in the house in the Winter must be kept warm. In a short time the little white embryo tucked away in the bean begins to grow. We say the bean sprouts. As the embryo develops, its little blunt tip grows down into the ground and gives off roots. At the same time its two tiny white leaves grow large and green, coming out from the seed-leaves (cotyledons) into the air and sunshine. As the stem lengthens the seed-leaves are lifted up above the ground along with the embryo. The bean thus seems to come out of the ground, and children are very apt to want to cover it up. But it has not really unplanted itself. The lower part of the stem and the roots hold it firmly in the earth. The bean on the damp cotton grows as well at first as that planted in the earth, but it cannot get food enough to continue growth unless it can thrust its roots into the earth. What enables it to grow at all on the cotton, since that does not supply food, but only holds the moisture, without which the bean could not sprout? There must be food somewhere, and it is found packed away in the thick seed-leaves, which contain a great deal of starch and a little of some other things. [Illustration: THE BEAN--EMBRYO-LEAVES, COMPOUND LEAVES, AND BEGINNING OF STEM] The young plant, under the influence of warmth and moisture, is able to draw out the nourishment from the seed-leaves. If we examine the seed-leaves after the seed has sprouted we shall find them less hard and firm; they have given part of their substance to the embryo. They have also turned greenish in color, while, as we know, the leaves of the embryo, which at first were so white and tiny, have also turned green and grown larger. Between the two embryo-leaves there is a little growing tip. The young plant now no longer depends upon the seed-leaves for its food. Down in the earth the roots are taking in nourishment, and up in the air the little green leaves are also busy supplying food to the growing plant. The little growing tip lengthens into a stem from which a leaf is seen unfolding. This new leaf is not shaped like the embryo-leaves nor like the seed-leaves. It has three leaflets. The stem continues to lengthen, and soon another compound leaf appears. Thus the stem lengthens and leaves keep coming, the little growing tip at the end of the stem always pushing upward. Very soon the stem becomes too long and slender to stand upright. Then it does a strange thing. It circles about as though in search of something. It moves very slowly, but if you notice which way it is pointing in the morning, and again at noon, and again at night, you will see that it has changed its position. Why does it do this? It wishes to twine about a support, and will continue circling about until it finds one. If there is none, the slender stem, unable to stand upright as it lengthens, will in time bend to one side or even lie on the ground; but the end still continues to circle about, and when at last it touches a stick or the stem of another plant or anything else about which it can twine, it continues its circling motion about the new support, and the vine as it lengthens finally becomes twined about it. How does the food which the plant takes from the earth and the air find its way to the different parts of the plant to nourish them? The plant food is in a liquid form called sap, which runs through channels in the roots and stems and leaves, and is thus carried to all parts of the plant. To a certain extent it is like the blood of animals, which finds its way all through the body and supplies food to the tissues. The plant is alive; it eats, it breathes; sometimes it even moves. It breathes the same air that we do, only it takes it in through tiny pores in the leaves. Eating and breathing, the plant continues to grow, leaf after leaf unfolding. At last, in the axil of one of the leaves there comes a little bud that does not unfold into a leaf but into a flower. The appearance of this first blossom on the plant the child has himself raised from the seed will be watched with eagerness, and its advent can be made a subject of general pleasure and notice in the home. The child's pleasure in his flower will be greatly increased if he finds that others are also watching and enjoying it. Here, too, is a chance to develop a certain respect or reverence for the beautiful and fragile flower. It is not to be picked. We are to leave this flower and see what becomes of it. If we pick it, it will soon wither and die. If we leave it where it is, it will continue to grow, and something very interesting will happen. After a few days the pretty white or red flower-leaves or petals will fall off; but any disappointment which the child may feel at the falling of the petals can be quickly changed into interest about what remains, for not all the flower fell. The centre of it is still there. It is a little green pod. It is so delicate that by holding it against the light one can easily see the little seedlets, or ovules, inside. "Ovule" is a good word to learn, and the easiest way is to use it at once, always referring to this little seedlet in the young flower-pod as the ovule. The word "ovule" means little egg; later, a word almost identical will be used for the eggs of animals. [Illustration: THE BEAN--THE SEEDLETS, OR OVULES, IN THE YOUNG PODS] Thus by a use of carefully chosen, well-understood terms the child has from the very beginning a dawning sense of the oneness of all life. He can be told that "ovule" means little egg, and that the seed of the plant is the egg of the plant, which hatches--sprouts--into the plant we see. It is better not to break the tender little pod to show the ovules, even if there are plenty of flowers. Look at the pod against the light and see the ovules dimly outlined. Each ovule is attached to the pod by a little stem which can also be seen with the light shining through the pod. The stem the child can look for when the peas are being shelled for dinner, or when lima beans are being shelled. If the pea or bean pod is opened carefully, the whole row of seeds will be seen attached to the pod, each by its exceedingly short stem. The ovary is a part of the plant in which grow the ovules. The perfect and clear understanding of just what the ovary is will be very helpful later, and the word "ovary" will be found extremely useful. The interest should not be concentrated on the ovary to the exclusion of other flower parts. The bright petals should have their share of attention. They form a nest, or home, or covering, to enfold or wrap about the delicate seed-pod. The thought that they are fragrant and beautiful because of the young life they cherish, and that they never appear excepting where there are young seeds to be cared for, and that every flower has the little pod or seed-cradle at its centre, can be made to cast a lovely glow over this side of the flower-life, which will later reflect more or less strongly upon all life. When the child discovers that the ovules are attached to the ovary by little stems, this very important question can be answered,--How are the ovules nourished? They must have food, or they cannot develop into seeds. The sap, which is the food of the plant, runs through the little stems that hold the ovules to the ovary, and thus, entering the ovules, nourishes them. The ovule has no embryo. It is a very simple little seedlet indeed. But after a while its little embryo begins to form and its seed-leaves to develop. When the ovule has developed in this way we call it a seed. It remains attached to the ovary, receiving nourishment from the sap until it is quite ripe. As the seed forms in its little pod, its thick sturdy seed-leaves become larger and fuller. The sap constantly stores up in them plenty of good food. Thus the parent plant provides for the seed, so that when it goes out into the world alone it may not perish until it has learned to care for itself. The food in the seed-leaves is the bank account which starts the young plant in life. When the seed is fully formed, its seed-leaves full of food, its embryo perfect, then we say it is ripe. It no longer needs to draw nourishment from the sap of the parent-plant. It is able to start in the world on its own account. When the seed ripens, its little stem withers away, so that the seed lies loose in the pod. In the case of the bean-pod, when the seed becomes free the pod opens, and the seed or bean, as we call it, falls out. If we look at a ripe bean or pea or any seed we shall find upon one edge of it the scar where the little stem was attached. The scar is the umbilicus or "navel" of the seed. The seed does not become free from its attachment to the pod until it is able to live alone. As long as it continues to grow it remains attached and receives the sap. As soon as it has its growth and no longer needs the sap it separates from the pod. This separation is easy and natural. There is no tearing apart, no mutilation. It is exactly like the falling of the leaves in the Autumn. It is, in short, the birth of the seed or infant plant. Some mothers talk of the mother-plant and the seed-babies from the beginning. They show how the little seeds are fed and protected, how they are literally a part of the mother-plant. Other mothers prefer to tell only the botanical story, leaving all application to animal life for later consideration. In either case the essential points are a clear understanding of the growth of the ovule in the ovary, the manner in which it is nourished and protected, and its final separation from the ovary to enter into the outer world as an individual provided with everything necessary to its needs. Some mothers use the words "sprout" and "hatch" interchangeably, speaking sometimes of the hatching of the seeds, in order to make more vivid the realization of the similarity of processes in the plant and the bird. They also speak of the birth of the seed. Clearly to understand the relation of the seed to the mother-plant is to understand accurately and scientifically the relation of every living creature to its mother. The child who enjoys planting the bean one season will want to plant it the next, for there is nothing children more delight in than planting things and watching them grow. This interest can be encouraged in any home, for where there is no available yard a few flower-pots of earth, or a box of it, will afford opportunity for a good deal of pleasure and instruction. The child can be encouraged to collect seeds that are formed like the bean, and plant them too. He will quickly discover that a peanut is made essentially like a bean, and he will be interested to plant some raw peanuts. The pea, too, he will soon add to his list. As the season advances he will discover the cucumber, melon, and squash seeds, and, with a little help, the apple, pear, and quince seeds, as well as those of the cherry, plum, and peach. The latter have very hard outer coats, but are formed in all essentials like the bean. Indeed he can have a very long list by the end of Summer. But he cannot make these green seeds grow. That is, many of them will not sprout until they have lain a certain length of time. So even where they are ripe and fall from their pods, he had better keep them until toward Spring before planting, even in the house. [Illustration: MORNING-GLORY SEED, SHOWING SEED-LEAVES AND EMBRYO] If he takes pleasure in examining his seeds, he will find in each one the tiny embryo tucked in between the seed-leaves; in the apple seed the young apple-tree, in the pumpkin seed the young pumpkin vine. Even the vegetables being prepared for his dinner can be interesting to him. As the peas are shelled he can see the pretty green seeds attached to the side of the pod. He can find the embryo even in the unripe seed, but he knows there would be no use in planting these green peas, for they are not yet fit to live apart from the mother-plant. If they were torn away and planted in the ground they would perish. Not all seeds have the food for the embryo stored up in the seed-leaves. If a morning-glory seed be soaked, it will swell up and soften, and the hard outer skin will burst. Inside will be found a tiny embryo with two thin, papery seed-leaves that contain no nourishment to speak of. But packed about the embryo is a rich food-substance which, though hard in the dry seed, becomes soft and gelatinous upon soaking, looking indeed not unlike the white of the egg, and having the same use; for it forms the first food of the embryo, which absorbs it. The embryo thus begins its growth, which continues until the roots and first leaves are sufficiently developed to supply nourishment. [Illustration: FOUR O'CLOCK SEED, SHOWING SEED-LEAVES AND EMBRYO] After the child has studied his beans, let him then study the morning-glory and four-o'clock seeds, which store the food separately from the embryo instead of in its seed-leaves. In every seed there is food enough stored up to give the embryo its first start in life. During the Summer the child can be helped to pass many pleasant hours looking at seed-pods and finding as many kinds as possible. He can discover how the ovaries are placed in the flower and wrapped about by the bright petals, being covered while yet in the bud by the green calyx. He can look at the different forms of ovaries and discover how some, like the bean, have only one compartment or cell, while others, like the apple-core, have five, and yet others, like the poppy pod, have many. If he is interested, he can quickly and unconsciously learn many of the more common botanical terms used in describing plants, so that when he comes to study technical botany he will find it shorn of most of its terrors. [Illustration: DIFFERENT KINDS OF OVARIES--BEAN, APPLE-CORE, POPPY POD] Certain botanical terms are valuable both now and later; used simply, just as we talk of table, chair, bed-post, garden-walk, etc., they are, as has been said, learned unconsciously. [Illustration: FLOWER--OVARY, STYLE, STIGMA, STAMENS, ANTHERS, PETALS, SEPALS] In teaching the later facts of the reproductive life, it is a great help for the child to know the names and uses of certain parts of the flower; in many flowers, as for instance the lily, the parts can be seen without pulling the flower to pieces. In the centre is the ovary, as the child already knows. Let him notice the long stalk on top of it and learn to call this the style. On top of the style is a knob--the stigma. Ovary, style, and stigma together make the pistil. Surrounding the pistil are six stamens, each having a slender stem or filament and terminating in a little box; this box is called the anther and is filled with flower-dust or pollen. Around these is a circle of bright petals. In many flowers, outside the petals is a circle of green sepals, which in some plants fall off or turn down when the bud opens. THE FLOWER _Sepals_--usually green and affording protection to the bud. _Petals_--usually large and bright. _Stamens_--{ filament (stem of anther) { anther (containing pollen) { ovary (seed-pod) _Pistil_--{ style (stem of stigma not always present) { stigma (knob at top of style or ovary) [Illustration: THE DEVELOPMENT OF THE YOUNG BEAN-POD FROM THE FLOWER] The care of the mother for her offspring, that impulse of nature found everywhere in nature's children, is beautifully illustrated in the flowers. When first the petals fall, leaving the tiny green pod, it stands up on its stalk, but in a few days it will be found hanging down. Why should this be? For one thing, as the pod turns down it gets out of the way of the other buds that one by one are preparing to blossom, for beans generally grow in clusters, one blossoming after another. Thus all the flowers have plenty of room and air and sunshine, and a lesson in unselfishness and thoughtfulness for others may be learned. Moreover, the hanging pod is better protected against accidents than the upright one. It is less noticeable and less likely to be knocked or broken off. The mother-plant takes every precaution possible for the welfare of the seed-children, even sending them far from home for their benefit. [Illustration: THE SHEDDING OF YOUNG SWEET-PEAS FROM THE POD] Every one has noticed how the sweet-pea pods are curled up when the seeds are shed. This curling takes place just at the moment when the pod opens to allow the seeds to escape. This sudden twisting of the pod flings the seeds sometimes long distances. If the seed were to fall close to the mother-plant it would find the soil impoverished in certain ways, the mother-plant having absorbed the food materials from it. If the seed can be hurled out of reach of the absorbing roots of the mother-plant, it may have a better chance; even if it should fall where other things are growing, it may find the peculiar food it wants sufficiently abundant, for not all plants absorb just the same things from the soil. [Illustration: THE SHEDDING OF VARIOUS KINDS OF SEEDS] Looking at the dried bean and pea-pods in the fall of the year, we shall find nearly all of them twisted. And looking over the other plants of the fields and hedges, we see how much trouble has been taken to enable the seeds to go out in the world and find new growing-places. Some seeds are snapped out, as the touch-me-nots and witch-hazels; some are supplied with flat wing-like surfaces to be borne by the wind, as the maple-keys and elm seeds; some have bristles or down upon which to float in the air, as the lilies, dandelions, and lettuces; some have hooks by which to attach themselves to the coats of passing animals; and others have yet other devices for getting to pastures new. The whole subject of how seeds travel about the world is very interesting, and collecting these wanderers and watching their habits will afford a rich summer's entertainment. Thus the child learns a thousand interesting things about the plant life,--among them, but not in any way prominent, the phenomena which are connected with the reproduction of the plant. This work can all be done before the child is eight years old, and in many cases it can be done much earlier, at least so far as inculcating the most essential truths is concerned. Many details will slip away in time, but if the work is thoroughly done the great primal truths of living things will stay, and as the child's life unfolds, they will illuminate it in certain directions. According to the age and opportunities of the child his information about the plant can be enlarged. The plant's method of breathing can be explained to one who knows something about the composition of the air, and of the use which the human body makes of the oxygen. The child who can understand it will be greatly interested to know that the plant uses the oxygen of the air, and returns carbon dioxide to it as a waste, essentially as his own body does. He should also know that the plant breathes very little in comparison to the animal, consequently it does not greatly affect the air, taking out but little oxygen and returning to it but little carbon dioxide. The plant's method of taking nourishment from air and soil is also very interesting. It is only the green parts of the plant that can take food from the air. The plant can become and remain green only under the influence of sunlight. So finally the plant owes its life to the power of the sun, just as in one way or another we all do. Plants in a dark place soon lose their green color, grow pale and sickly, and finally die. All green leaves and the young green twigs are able to take food from the air. The food they thus take is carbon dioxide, the very thing both plants and animals breathe out as a waste, and whose presence in large quantities makes air unfit to breathe. But the plant must have the carbon dioxide and can get it only from the air, so it is constantly withdrawing this harmful substance from the air and converting it into plant tissue. It consumes only part of the carbon dioxide, however, for the oxygen that is tied up in the carbon dioxide is set free and given back to the air, only the carbon being retained. So the plant is continually taking in the destructive carbon dioxide and giving out the wholesome oxygen, thus keeping the air pure and fit for us to breathe. In short, the plant eats with its roots and with its leaves. With its roots it eats certain things it finds in the earth, and with its leaves and other green parts it eats the suffocating gas we breathe into the air. This important function of the plant, in supplying the oxygen we need and in destroying the harmful carbon dioxide, can be illustrated in many graphic ways. We depend upon the plants for our very existence in this respect: they stand between us and destruction from excessive accumulations of carbon dioxide. On the other hand, the carbon dioxide is so important to the plant that it could not exist without it. All the carbon it gets is obtained from this source. Wood is largely carbon; a charred stick which retains its full size and shape is almost pure carbon. Thus the breath of our bodies is converted by the plant into the wood from which we construct our houses, furniture, etc. In a certain sense the chair we sit upon is made of the breath of our bodies. Besides these debts to the plant, we finally owe to it the food we consume, which comes from the plant, even meat being but vegetable matter one step removed. The plant changes the chemicals which the animal cannot use in their crude form, into plant substances which animals can use. Thus the vegetable and animal kingdoms are mutually dependent upon each other. Neither could exist, at least in its present condition, without the other. Not only will such facts as these be interesting to most children, they will deepen the dawning consciousness of the fundamental unity of all forms of life, which it should be the province of nature-study to develop. It may not be out of place here to say a few words about the picking of flowers. Children instinctively want to pick them. They wish to possess, touch, caress these lovely objects. If left unguided, this tendency shortly degenerates in many children into a desire to pick every flower in sight. A walk taken by such children through the fields can be traced by the wild flowers that strew the way. Great handfuls are gathered, and then, becoming burdensome, are thrown down. The child who lovingly watches his flowers grow and blossom will be less likely to destroy in this wanton manner. Here, too, is a good opportunity to teach him to be thoughtful and generous to others. If he carelessly tears up and throws away the flowers, those who come after him will not have them to enjoy; it is far better to look at the flowers and admire them in their own homes and leave them there. A little crowd of hepaticas at the root of a tree in the woods is one of the most charming sights of spring. Let the child who finds such a treasure call the rest, that they too may enjoy the pretty picture; let the children get down and put their faces against the flowers if they want to smell them, and then go away leaving the beauty undisturbed. Their adult comrade at such a time by exclaiming appreciatively over the sweetness of the little scene, the bright flowers against the dark tree, the green moss growing over the rock at one side, can often open young eyes to a harmony of beauty which will cause the whole composition to be recalled later with pure pleasure; a far deeper and higher pleasure this little picture lingering in the memory than any number of flowers torn from their places soon to wilt in the hands of the vandals whose only thought is how to get the most in the shortest time. Should children never gather flowers, then? Of course they should. But they should learn to exercise restraint, and as they grow older, judgment. They can easily be persuaded to gather only a few flowers. A few are almost always more beautiful than a great mass, and there is no exception to this whatever where the delicate spring flowers are concerned. Let the child carefully gather a few to take home to mother, father, sister, aunt, some dear one who has not shared the walk. These flowers should not be neglected, but at once put in water, placed where they can be seen and enjoyed, and the water should be changed every day as long as they last. In this way the flower gives real pleasure to a number of people, and the child learns several lessons valuable to the formation of his character. As the child grows older, he can be taught not only self-control against gathering useless quantities of flowers, but also to exercise judgment in regard to those he does pick. For instance, seeing a flaming bush against a superb background of green foliage, shall he disturb the poise of the picture for the sake of taking some of the flowers? Better is it to look about for similar flowers less beautifully placed. Instead of culling from the little hepatica company at the tree root, let him search for more hidden or less beautifully grouped flowers. The isolated flowers will be just as pretty after they are picked as are those in the fortunately placed groups; for he will soon learn that with the flower he cannot take its surroundings excepting in the memory. In this way he will be able to carry away a beautiful mind-picture such as would not remain if he had destroyed it; he will become more observant of the flowers as pictures, cultivate his taste, in short, and also learn to enjoy beauty without destroying it. Wanton destruction of flowers should never be countenanced, no matter how abundant the flowers may be. Self-restraint is not inculcated for the sake of saving the flowers so much as for the influence it will have upon the development of the child, although there are parts of the country where one would like to see it exercised for the sake of the flowers themselves. The child who learns to respect flowers will never be one of that discreditable company who by sheer vandalism are constantly driving the wild flowers farther into the back country, finally exterminating whole species. In many parts of New England, banks which were carpeted with arbutus a generation ago are now devoid of a single root. Spring may come and Spring may go, but no may-flowers will ever again shine from those banks to delight the eye of the woodland wanderer. All the generations to come must be deprived of the pleasure of these delightful flowers, the earliest visitants of spring--to what end? Did the pleasure they gave to those who took them compensate in the least degree for their loss to the world? Truly not. In all the open places near cities, where flowers would delight the greatest number of eyes and hearts, there are no flowers, and this because those who went first had no respect for the flowers themselves or for the rights of those who came after. Not only should the child learn to exercise judgment in gathering flowers, but he should also learn how to gather them properly. If the arbutus had not been carelessly torn up by the roots and trampled on, it would have yielded its whole tribute of blossoms year after year without disappearing. If the arbutus-gatherers, knowing the nature of the treasure they were gathering, had gone armed with scissors and had clipped the blossoming ends without other injury to the plant, at the same time taking care not to trample it, the banks would still have been clad in beauty. VII THE FERTILIZATION OF THE FLOWER As a preparation for this work, let the children notice the flower-dust or pollen that shakes out of the flowers or is seen clinging to the anthers. [Illustration: BEE--SHOWING POLLEN-BASKET] The child presently discovers where the pollen comes from. It is hidden in the anthers. He can hunt in all the flowers to find these little pollen-boxes, some of which, as in the goldenrods, are so small that he will have hard work to find them, even though they shed such clouds of pollen. He can notice the different kinds of stamens, see how some have long stems or filaments, others short ones, others again none at all. The filament is of no other use than to hold up the anther. The anther with its pollen is the important thing; so there may be useful stamens with no filaments, but never useful stamens with no anthers. The amount of pollen in the flowers is always astonishing and interesting. Why should there be so much? That the bee gathers honey from the blossoms is one of the earliest things the child learns. Just whereabouts in the flower-cup, and just how the bee finds this honey, how it carries it home, where and how and why it stores it in the hive, is one of the most fascinating of stories, as good as a fairy tale. In connection with this comes very naturally the story of the bees and the pollen. The child will be delighted to learn that the bees collect pollen as well as honey; that the honey bees and bumble-bees have baskets on their legs on purpose to carry it home; that they knead it up with honey and make it into what is known as bee-bread. We seldom see bee-bread these days, as patent hives furnish all the honey found in city stores and no bee-bread is sold. In remote country places, however, where the honey is removed _en masse_ from the hive, there will be plenty of bee-bread to give piquancy to the children's bread and honey. Moreover, where bees are kept, the bee-keeper can usually be persuaded to take out a little bee-bread for the children to see and taste; for it is always present no matter what the kind of hive used, though it is not always easily obtainable, for where their household arrangements permit, the bees generally prefer to store it in the lower chambers away from the honey. Thus the flower supplies large quantities of food for the bees and for us, and long ago, before America was discovered and before cane-sugar came into use, the people depended upon honey for their sweetening. When the children have found how general is the presence of pollen in the flowers, where it comes from, and how it is gathered by the bees, they can learn that the pollen is valuable to the plant itself. It is indeed one of the most necessary parts of the flower, for without it the ovules could not develop. The effect of the pollen upon the seeds can be prettily illustrated by a simple experiment. Take two or three little pots of geraniums whose buds are just ready to open. Be sure to have single geraniums, and to stand them where they will not be disturbed and where the wind will not blow upon them. Shortly after the flower opens, the anthers will be seen crowded in its throat and covered with pollen. After a few days the pollen will have dried up, and the style, tipped with a five-rayed star-like stigma, will push up above the anthers. Mark pot No. 1 as untouched. From pot No. 2 carefully take a little pollen on the end of a small clean paint-brush or tooth-pick and touch with it the five-rayed, star-like stigma of the flowers in pot No. 3. Be careful not to let any of it touch the stigmas of the flowers in pot No. 2, the pot from whose flowers the pollen is taken. Leave the flower-pots undisturbed and watch results. When the flowers finally drop their petals, in pots No. 1 and No. 2 there will be no seed-pods remaining, everything will drop, including the little flower-stalks and the main stalk supporting the whole cluster of flowers. In short, no trace of flowers will be left. So far as seed-forming is concerned, the flowers might as well never have blossomed. Very different will be the result in the flowers of pot No. 3. These received the pollen on the stigma, and in some way this pollen affected the ovules so that they began to develop. We say the flower was fertilized by the pollen, and "fertilized" is a valuable word to learn at once. When the petals of the fertilized flowers fall, all does not fall. There remains the ovary with the long style and the star-like stigma. The ovary continues to grow, as do the seeds within it. Since the geranium is a house-plant, raised under unnatural conditions, not all the fertilized flowers will succeed. Some may fall at once, like the unfertilized ones. But out of the whole bunch of fertilized flowers some will be almost sure to start the development enough to show that in some way the fertilized flowers were able to produce seeds, while the others will in no case make any attempt at seed-forming. Even though none of the seeds come to perfection, the fact that they start at all will demonstrate the effect of the pollen. The geranium is a good plant to use in illustrating this point, because it is so constructed that it cannot fertilize its own flowers. What the child thus far learns is simply that the pollen is in some way necessary to the development of the ovule. If the experiment with the geraniums is not practicable, the child can be told that the pollen is necessary to the development of the seed, that it falls upon the stigma and nourishes the little ovules down in the ovary, and that no seed can form without the aid of the pollen. All the seeds we plant in the flower gardens or in the vegetable gardens, and all the grain we sow in the fields, are produced by the help of pollen. All the peas and beans and other seeds we eat owe their existence in part to the pollen, and without it they could not develop. Some parents teach their children at once that the pistil is the mother-part of the plant, caring for the young seeds, the stamens the father part, providing for them, and that the stamens and pistil growing in the same flower are brothers and sisters. Other parents prefer to use only botanical terms, leaving the extension of the thought to later consideration or to the child's own logic, for children often reason out all the facts--in a very general way, of course--from only this botanical study. But we are not yet done with the pollen. It not only assists the ovule to develop, but it impresses upon it its own characteristics. In other words, the seed inherits from the pollen as well as from the ovule. Inheritance is a very wonderful thing. It is that power which causes the offspring to resemble its parents. In some wonderful way the tiny ovule, the tiny pollen grain, remember everything about the plant they came from and are able to transmit this memory to the developing offspring, so that it may become like its parents. Again, the child under eight can understand the principal facts of fertilization. The older child can add to his stock of facts, and one of the things he will be likely to want to know is how the little pollen grain up on the stigma can influence the ovule down in the ovary. We know how the ovule is formed. We know that it grows from the inside of the ovary. If we were able to examine the development of the pollen grain inside the anther from its very beginning, we should find the same thing true of it. The anther is a little box like the ovary, and the pollen grain grows from the inside of it, being at first a part of it and nourished by the same sap. When it became ripe it fell free into the anther cavity. We then have a little box full of ripe pollen grains.[1] The pollen grain is like the ovule in structure, only much smaller. It is so tiny and the anther so small that we cannot watch its development as we can that of the ovule. But botanists have taken great pains to examine the pollen and to watch its development under the microscope, so that from them we know the truth. If we examine the young ovule we find it apparently nothing but a little sac full of a semi-liquid substance. This semi-liquid substance, or at least a part of it, is alive and is very important. It is protoplasm, which is the only living substance; all the living parts of plants and animals are made from protoplasm. [Illustration: POLLEN GRAINS (MAGNIFIED), AND STIGMA] The pollen grain is also a little sac containing protoplasm. Thus we have these two little sacs of living substance, each growing in a similar manner, one to the inside of an ovary, the other to the inside of an anther. Naturally, it is the living substance in these little sacs that is important. It is the living substance of the ovule that unites with the living substance of the pollen grain to become a seed; or, to say the same thing another way, it is the living substance of the pollen grain that unites with that of the ovule to become a seed; or yet again, it is the union of these two living substances that enables the seed to develop. [Illustration: THE POLLEN TUBE PASSING THROUGH THE STYLE TO THE OVARY] To understand how the pollen substance finds its way to the ovule substance let us examine the pollen grain a little more carefully. Pollen grains are of many shapes, though usually they are globe-shaped, or football-shaped. Tiny as they are, the outer skin is often marked with grooves and ridges in a very ornamental manner. They have two skins, an outer hard one, a softer inner one. The outer skin is not equally thick and hard all over. It has little glazed spots sometimes, like little glazed windows. Now, when the pistil is ripe the stigma is _sticky_. When the pollen grain falls upon this sticky stigma its inside wall swells up, just as the bean does when we soak it. But the outside wall cannot swell, consequently the inner wall finally breaks through at one of the weak spots in the outer wall. Then the inner wall absorbing moisture and nutriment from the stigma actually grows, becoming a tube, which finds its way down through the style. The living substance of the pollen grain runs into the tip of this tube, and so is carried with it down through the style. The tube is nourished by the juices of the style as it goes along, and finally it gets to the ovary and the ovule. Every ovule has a tiny opening, or micropyle as it is called, and it is now easy to guess what that is for. The pollen tube pushes straight toward the micropyle, enters into the ovule through the micropyle, and then the living substance it has carried all this distance in its tip breaks through its delicate wall and mingles with the living substance of the ovule. When this has happened, the ovule begins to grow and to develop into a seed. [Illustration: ENTRANCE OF POLLEN-TUBE THROUGH THE MICROPYLE TO THE OVULE] We see that the whole pollen grain could not possibly force its way down to the ovule. It cannot move of itself, for one thing, and if it could it is too large to pass between the tissues of the style. So it simply sends down the long tube, which grows fast, pushing along through the style, whose tissues are rather loose, and carrying with it the only valuable part of the pollen grain, its living protoplasm. No ovule can possibly grow into a grain without this tiny bit of pollen. In explaining this union of the two protoplasms, the child's mind can be turned upon the wonderful mystery--one of the great mysteries of the universe--of how this tiny atom can influence the whole future plant. There is ample opportunity here to elevate his mind and spirit to a high plane, and, by talking of the wonders of inheritance, to give many a hint for future reflection. Without this law of inheritance the world would be chaos. Imagine the seed of a rose sometimes developing into an oak tree, the egg of a bird into a bee or a trout. Imagine eggs developing haphazard into anything. There would be no use in living. Nothing could be depended upon. But there is no danger that any such thing will happen: the law of inheritance is unyielding. From a rose seed must come a rose bush,--and this is good. But on the other hand, from the seed of a weak, poor plant will grow another weak, poor plant. Whatever the parent is, good or bad, that must the offspring be. But sometimes the offspring inherits only the best in the parents, and so is better than they. Thus in gathering his seeds, the child will select only the largest and best and take them from only the best plants to put in his garden the next year, at the same time planting beautiful truths in the garden of his soul. Not the least of these truths is a profound sense of the immutability of law. Through his nature-work the child can learn as nowhere else the stern, unbreakable decrees of law, and the respect and reverence due to it from every intelligent being. Another important and far-reaching fact that the child can learn from his garden is, that his plants are good or poor according to the care he takes of them. They must have the right kind of food (soil), the right amount of water, the right temperature and surroundings,--some loving the open sunshine, others needing to be partly protected from it. In short, according as its environment is suited to its needs, and as its inheritance is good or bad, will the plant be strong and handsome or otherwise. Another truth to be learned from the flowers is the value of cross-fertilization. This was demonstrated by the great Darwin, who fertilized a number of flowers with their own pollen, and an equal number with the pollen from the blossoms of another plant of the same kind. When the seeds were ripe he gathered them, carefully keeping those of the self-fertilized flowers separate from the others. The next season he planted both sets of seeds under exactly the same conditions, that is, they had the same soil and moisture, the same sun and air, and the same care. The plants that grew from these two sets of seeds were very different, those from the self-fertilized seeds being smaller and weaker in every way than those from the seeds fertilized with pollen from another plant, or cross-fertilized, as we say, thus proving that it is not best for the plant to be self-fertilized. Someway, it needs the stimulus from less closely related pollen in order to grow vigorously and perfectly. While the cross-fertilization of the same order of plants is so desirable, it is not possible for the pollen of one order to fertilize the ovules of another order. There must be a certain degree of similarity between flowers able to fertilize each other. The pollen of an apple blossom might, for instance, rest upon the stigma of a lily, but the pollen could not penetrate to the lily ovule. It would have no effect upon the lily. That the seed inherits equally from the ovule and the pollen grain is a truth that should be impressed in many ways. It is very wonderful that anything so small as a pollen grain, often as small as the tiniest speck of dust, should be able to transmit to the young seed the peculiarities of the plant from which it came. That it does this, the child himself can prove in a most interesting way. He can plant some white petunia seeds in one side of his garden, and some red ones in the other. The seeds should come from a reliable florist's in order to be sure of results. When the petunias ripen their seeds, those from the white flowers should be gathered and carefully labelled, and then those of the red flowers, care being taken not to mix the two colors. The next summer, plant the seeds as before. When the flowers blossom, those in the white bed will no longer be white,--some may be, but others will be red, and still others red and white. The same will be true of the flowers in the red bed. What has happened? The bees going from flower to flower have carried the pollen from one bed to the other, and some of it, rubbing off on the stigmas as the bees searched for honey, fertilized the flowers. Thus some of the ovules of the white flowers received an impression of red from the pollen of the red flowers, and grew into red flowering plants. In others where the impression of red was less strong, the result was the production of red-and-white spotted flowers. By fertilizing white flowers with pollen from red ones we can almost always get seeds that will develop into plants bearing flowers that are not white. What is true of color is true of other characteristics of the plant, such, for instance, as size and shape of leaves, habit of growth, size, shape, and quality of fruit, etc. Thus by careful cross-fertilization, we are able to produce not only beautiful and new blossoms, but also many delicious new fruits. Most of our cultivated fruits have been produced in this way. For instance, if two species of wild strawberries were found, one, large and beautiful but sour or tasteless, the other, small but delicious, the two could be bred together until finally a perfect berry, large and well-flavored, would result. [Illustration: FLOWERS NEEDING CROSS-FERTILIZATION, SOME WITH OVARY BUT NO STAMENS, OTHERS WITH STAMENS BUT NO OVARY] When the children are interested in their gardens they can try to make a new flower, using for the first experiments one that comes up from the seed, blossoms, and matures its seeds the same year, and also readily changes its color as a result of cross-fertilization. Such are the petunia and the sweet-pea. The prettiest new flower produced can be marked and its seeds saved for future use, and the flower can have a name of its own. Florists often name their choice new flowers from some beautiful woman, and it would be a pretty tribute on the part of the child to name his favorite new petunia or sweet-pea after his mother. Of course this work will necessarily be very crude and the results uncertain, since the successful production of new plants is a science in itself; but enough can be done to interest the young experimenter thoroughly and enable him to learn many valuable lessons. In these early, childish experiments, an interest in gardening may be awakened, which will last through life, the man, the woman, finding rest, relaxation, exercise, and pleasure in going from the trying daily work to the garden a while every day. Even a plot of ground a few feet square can afford great opportunity for experiment and beauty. Cross-fertilization among the plants does not, of course, depend upon man as an agent. Since cross-fertilization is so valuable, it is not surprising to find many devices in the plant world for securing it. Honey and color, which attract winged messengers, are among the most universal helps to cross-fertilization. In many cases, the structure of the flower is such that it cannot fertilize itself. In the geranium, the stamen and the pistil in the same flower mature at different times. In some species, as among the lilies, the style is so long that the pollen could not fall upon it without artificial aid. Some flowers are so constructed that they can be fertilized by certain kinds of insects and by no others; among these are the orchids and our clovers and milk-weeds. Again, some flowers have an ovary but no stamens, while a neighbor has stamens but no ovary, making self-fertilization absolutely impossible. Indeed there is nothing more fascinating in the study of botany than the methods by which the flowers secure cross-fertilization, nearly all of our common garden-flowers affording illustrations. Here too, is a field where the young botanist can do really valuable work, for while much is known and has been written on the subject, much remains unknown. There are many books that give valuable and delightful information about cross-fertilization. The method of fertilization of the flowers satisfactorily accounts for the great amount of pollen produced. Being blown by the wind or carried by insects, much of it is wasted, consequently there must be ample allowance made for this waste. So the flowers produce thousands of pollen grains which they can never use themselves. VIII WHAT CAN BE LEARNED FROM THE LIFE OF THE FISH Whatever is universal is good. Whatever is universal is true. Whatever is universal is beautiful. Nothing disperses, so to speak, the fogs enveloping the thought of sex like the realization of its universality. The air clears when we know that every living thing is bound by the same laws, even the flowers in our gardens. We have an interesting testimony as to the helpfulness of this thought from one of the great educators of youth, Fröbel. Speaking of his own childhood when he became conscious of what his father, who was a minister, was constantly meeting in his parish work, he says: "Matrimonial and family relations were often the subject of his admonitory and corrective conversation and remonstrances. The way in which my father spoke of this, made me consider the subject as one of the most pressing and difficult for man, and in my youth and innocence, I felt deep grief and pain that man alone among created things should pay the penalty of such a sexual difference that made it hard for him to do right.... Just then my oldest brother, who lived away from home, came back for a time, and when I told him my delight in the purple threads of the hazel buds, he made me notice a similar sexual difference among flowers. "Now my mind was satisfied. I learned that what had troubled me was a widespread arrangement throughout nature to which even the quiet, beautiful growths of flowers were subject. Henceforth human and natural life, soul and flower existence, were inseparable in my eyes, and my hazel blossoms I see still, like angels that opened to me the great temple of nature.... Henceforth it seemed as if I had the clue of Ariadne, which would lead me through all the wrong and devious ways of life; and a life of more than thirty years with nature, often, it is true, falling back and clouded for great intervals, has taught me to know this, especially the plant and tree world, as a mirror--I might say, an emblem--of man's life in its highest spiritual relations; so that I look upon it as one of the greatest and deepest conceptions of human life and spirit when in holy Scripture the comparison of good and evil is drawn from a tree. Nature, as a whole,--even the realms of crystals and stones,--teaches us to discriminate good from evil; but, for me, not so powerfully, quietly, clearly, and openly as the plant and flower kingdom." The stronger this feeling of the universality of sex, the more dispersive, as it were, is the thought of the subject. It would be difficult to connect personal and impure thoughts or feelings with a star whose distance in space was realized; and so with all other thoughts, the more they can be elevated into wide, general regions, the less disturbing they will be likely to become. All the facts of sex-life can be learned in the flower, and the associations thus indelibly impressed cannot fail to leave at least a trace of fragrance and loveliness on even an obtuse nature. No matter what the later experiences or mistakes may be, the whole conception of this side of life cannot sink so low as might be the case if there were not this flower-sweet background. And that is worth something. It is not difficult to pass at once from the flower life to human life, and there are cases where this may be advisable. When, however, the beginning-work has been done with young children, and when we consider all the stress laid upon nature-work these days in school and out, and all the books written and all the stories told of living creatures of all kinds, it is helpful and easy to linger in the delightful and impersonal realm of the lower life yet longer, with this distinct advantage, that the _feeling_ of universality, which is very different from the _thought_ of it, will be strengthened. For several reasons, the step from plant life to animal life can well be taken by means of the fish, particularly with little children. There is nothing prettier than living fishes in water. The fascination they have for all conditions and ages is shown by the crowds always seen at exhibitions of live fish in aquaria. The child can have his little aquarium at home, which may consist of a glass globe plentifully supplied with some pretty water weed and a goldfish or two. Fishes do not like the bright light all around them, and should be provided with some sort of refuge, like the water weed, or if the tank is large enough, with stones piled up to make a cave. For the same reason, the globe should not be set in the window or on the middle of a small table, but should be placed where at least one side of it may be shadowed by something. Pebbles should be put in the bottom of the tank and not too many fishes crowded together. They need room to move freely, and also plenty of fresh water for breathing. At the bird-stores small aquaria can usually be bought and fitted out with the proper amount of water plants to balance the breathing of the fishes. For the impurity breathed out by the fish is the same as that breathed out by all creatures, the carbon dioxide which it discharges into the water being just what the water plant needs to grow on. Also the water plant returns pure oxygen to the water, which is just what the fish needs to breathe. This story of the interdependence of the two, and the possibility of so balancing the plant and animal life in the tank that it is never necessary to change the water, can be made very interesting, and, needless to say, very illuminating. The fish cannot live out of the water, and yet it breathes air. There is always air in the water unless it has been artificially removed as by boiling, and this little bit of air is enough for the fish, which is cold-blooded and does not need so much fuel to keep its vital forces burning. But this little it must have, and it will suffer for the want of it, just as we suffer in a very close, unventilated room; and if the supply should become too small, the fish will die, just as we should die in a room where no fresh air could enter. So the fish must have the water changed unless there is enough plant life in its tank to keep the air pure. When suffering for air, the fish shows signs of distress, which should never be ignored. If it keeps close to the surface of the water with its mouth up and frequently swallows the outside air, that is a sign it needs fresh water. If it does not have it after a while it will die, as it cannot live on air undiluted by water. Fishes need very little feeding, particularly if there are water plants in the tank; they find food from them. The best way is to follow the directions of the man who sells you the fishes. If too much food is given them it quickly fouls the aquarium, and then the water must be changed and everything cleaned up. In changing the water, care should be taken to have that which is put in about the same temperature as that taken out. A sudden application of too cold water is not good for the fishes. The children should take care of their pets themselves and see that they do not suffer. The motions of the fish are what make it so attractive. How does it swim? Not with its fins to any extent. The whole back part of the body, including the tail, is moved from side to side as the fish swims. It moves its tail as a paddle is used at the stern of a boat, and so the fish paddles himself along. The fins are used more as balancers. They keep the fish upright in the water. As soon as it stops using them, it turns over on one side. The fish opens and shuts its mouth constantly; it appears to be swallowing water. And so it is, so far as its mouth is concerned, but the water it takes in does not go down into the stomach. It is not really swallowed, but passes out at the gills, which are also constantly opening and shutting. The gills are red inside and are covered with a fine network of blood vessels. The air in the water moves against these delicate blood vessels, which are able to take what they need--the oxygen--from it. Thus the fish uses gills instead of lungs for breathing. Sometimes, fishes pick up pebbles in their mouths and drop them again. Some fishes, but not goldfishes, make noises. The adaptation of the fish to its surroundings is interesting. Not only is its form the very best for moving quickly through the water, but its covering is peculiarly appropriate, many fishes having a hard, protecting coat of shining scales. These scales, besides being beautiful and useful, are interesting in another way, for we know that they are only modified hairs, growing from the skin as hairs grow but having their form and size developed in special ways to serve their purpose. Scales and feathers are only another form of hairs. Many interesting stories of fishes can be told or read to the children, and among other things they can learn about the swim-bladder, the large, strong air-sac, which can be compressed or distended at pleasure, making the fish lighter or heavier and enabling it to rise to the surface of the water or sink to the bottom. In Nova Scotia, where many codfishes are caught, the swim-bladders are called sounds, and are cooked as a delicacy. In the spring of the year we eat the roe of fish, which is nothing more nor less than fish eggs. Wherever shad are used, the children will be familiar with the shad roe; and in the South mullet roes are universally used. The people there dry them in the sun, and the children particularly are very fond of them. The Russian caviare is the eggs of a species of fish, and is considered a great delicacy by some people. Where do these eggs come from? The fish market or the kitchen on fish day will answer the question. The child who is privileged to pass part of the summer at the seashore where fishermen ply their trade will have ample opportunity to know, as will the child who goes fishing in any brook or pond and is allowed (as he always should be) to clean and cook the fish he has caught. Also the smelts, which are cooked whole, only the intestines being removed through a hole near the gills, will answer the question. [Illustration: THE OVARY OF A FISH] The eggs of the fish are contained in a sort of double pouch or sac, shaped something like an old-fashioned silk purse. These sacs open into the intestine near its exit. They are the ovaries of the fish. From the inside of each ovary the tiny eggs, or ova, grow, just as the ovules grow in the plant ovary or seed-pod. At first they are a part of the ovary; later they grow larger and fall loose, until the ovary is filled with them. The ovary is always inside the fish. It is there when the fish is born, and even then there are the tiniest hints of ova in it. But the ova do not grow large until the fish is mature; they wait until the fish has developed its strength, its bone, and muscle. Then in the springtime they grow rapidly. They grow until they are ripe, when they lie free in the ovary; and others grow and are freed in the same way until the ovary, which has also enlarged to accommodate them, is quite full. The female fish is larger than the male, and looks plump and rounded at this season. In course of time the eggs thus developed will be shed--or born--whether they are fertilized or not. But, if they are not fertilized, no further growth will take place in them, and they will soon perish. The child, knowing about the fertilization of flowers, can easily be led to see that the fish ova, like the flower ovules, cannot develop without pollen. The anthers containing the pollen are found in the male fish, and look like the ovaries, only they are not so large and their contents are not so firm. They seem filled with a formless substance instead of with little globular eggs. Under the microscope this formless substance is seen to be made of a semi-fluid material in which are held millions of pollen grains! Only we no longer call them pollen grains. We may call them fertilizing cells if we please, though there are several names for them. But they are essentially the same as pollen. They grow, in the same way, from the inside of the anther (which may now be called the testicle) and become free when ripe. The pollen grains cannot move of themselves; the fertilizing cells can. Each fertilizing cell is like an ovum, excepting that it is not so spherical and is lengthened into a sort of lash by which it can propel itself through the water. When the ova are laid by one fish, the other swims over them and the fertilizing fluid is expelled into the water just as the eggs were. There is no union whatever between the parents for the purpose of fertilization. As soon as a fertilizing cell comes in contact with an ovum it seeks to enter into its substance, and as soon as this has happened, the two cells thus united begin to develop into a very tiny fish. As soon as the change begins, we have the _embryo_ of the fish, which thus corresponds to the embryo of the seed. There is one great difference between the ovary of the plant and that of the fish. When the plant ovary is ripe, its seeds are shed, and then the ovary itself falls off. The plant ovary thus bears only one set of seeds. In the fish, the ovary always remains in the fish, and after the eggs are shed, it shrinks up to a very small size, and remains so until it again develops and becomes distended with more eggs the following season. The same is true of the fish's testicles. When the time comes, the fertilizing material is expelled. After this the sac shrinks up to small size until the following season. When the embryo has grown to its perfect form, the egg-shell is broken and out swims the young fish. When it leaves the shell we say it hatches, just as we say the plant embryo sprouts when it leaves the egg-shell or seed-shell. Like the pollen of the flower, the fertilizing cells of the fish cannot act upon any ova but those of its own species. The young fish, like the young plant, inherits characteristics from both parents. From its father it may acquire a certain shape, certain markings, a certain disposition. Since the father's part in the creation of his offspring is less obvious and apparently less intimate than that of the mother, the child can be helped to put a certain value on the thought of fatherhood which later will strengthen the bond of union between himself and his own father, deepening his love for his father and his confidence in him. That the boy love his father is as necessary to his welfare as that he love his mother, and the mother should, in all the early years in which the sex instruction may fall most heavily on her, impress upon the young heart the beauty and glory of paternity. The sacrifice of the father who gives all his strength and time, scarce allowing himself a moment of relaxation or absence from business that he may provide for the needs of the family, is as great as the sacrifice of the mother who devotes her time and strength to caring for the home and the children. The tendency in teaching young people is to lay all the stress on motherhood and mother love, which is a manifest injustice to the human father, who deserves not only the natural love of his children, but the deeper, more consecrated love which comes from a pure and perfect knowledge of fatherhood. Perhaps nothing will help a young man at the most critical age of his life so much as his love and faith in his father. And perhaps nothing will tend to lift the whole subject of paternity in the popular mind to the plane where it belongs, as will this love and knowledge, when it is bred in the child from his early years. Many difficulties in handling this subject that become insuperable might never even exist if the knowledge of fatherhood, if love and respect for it and for the father as the giver of life, were bred into the boy at an early age. Moreover a certain shyness, which often makes it more difficult for fathers to talk to their sons on these matters than for the mothers to do so, would not have existed if they themselves as children and youth had been educated to a complete knowledge of the sex-life by one or both parents. The cause of this shyness is in many cases ignorance of how to present the facts, and a misconception of the difficulties of speaking to a pure-minded child about them. Nothing surprises the parent more than the way difficulties vanish when once the course of instruction to the youth has been entered upon. In the lower life the father seldom cares for his offspring; and this is true among the fishes, where neither parent as a rule assumes any other responsibility than properly disposing of and fertilizing the eggs. Where, however, any care is taken, it not infrequently devolves upon the father instead of the mother. This is true of the fresh-water black bass and of the stickleback, where the father protects the eggs until they are hatched, and protects and cares for the young fish. In the case of the stickleback, the father even makes a nest to contain the eggs. Thus far, the process of the renewal of life is, so to speak, impersonal. The eggs are laid by one fish and fertilized by the other, this being necessary to the development of the young. The parents are endowed with an instinct which informs them when the time is at hand; and the male fish guided by this instinct applies the fertilizing material where it is needed,--that is, over the surface of the fresh-laid eggs. The number of eggs laid by fishes should be noticed, as it is a fact which will be useful later. Several millions of eggs have been counted in the ovaries of one fish. The number of fertilizing cells in one testicle would be incalculable. Fish eggs and young fishes are liable to many fatalities; they are destroyed in immense numbers. Consequently, if the race is to survive, there must be an almost inexhaustible supply. Fishes kept in confinement will not as a rule multiply. Nothing is so sensitive as the reproductive system. Lacking certain stimuli which it finds in its natural surroundings, it will not become active. The goldfish in the globe will, if a female, have the ovary containing undeveloped ova, the male will have the testicles containing the fertilizing cells, but these will not mature. It is as though the whole system of the fish missed the freedom of space, the changes of season, the variety of substances at the bottom of the water,--all that goes to make "home" for it, and so languished in body as well as spirits. The child who, in connection with a multitude of other interesting facts concerning fish life, learns those concerning its multiplication, will look upon them as perfectly natural and matter-of-fact. But, some one objects, will not the child at this point guess the whole truth? Suppose he does? Is not that just what we want him to do? Is it not a sign that he has a good reasoning mind? He may arrive at the right general conclusion, but he has a conception that is very general, vague, not at all personal, and entirely lacking in any material for malodorous thoughts and feelings. By constantly turning his thoughts to the wonders and truths of heredity and to the marvel of the development of living things from such insignificant yet momentous beginnings, and by telling him interesting facts of animals and plants along these lines, his thought can be kept general and on a high plane. Where details are demanded, the parent ought to be thankful that these are presented to him for elucidation instead of to some incapable outsider, and he can meet the demand according to circumstances,--all of which will be discussed more fully presently. If the parent keeps ever in mind the fact that the child _must know_ some time, and ought to gain a high conception of the subject before being exposed to degrading influences, if he asks himself in all honesty, "Unless I answer this, who will? and how?" he will be helped to do what in his own heart he knows to be his duty. Moreover, there is a great gain to many a child in learning the main facts at an age where they do not appeal powerfully to his imagination nor move his senses. Later, when any reference to the subject may have this effect, and when there is enough to understand and meet without going back to the rudiments, it will be much less difficult to give the needed aid with this background, which causes the child to feel that he has "always known." To have always known a thing robs it of any great special interest. We pay no attention to the sun that shines upon us, but if this were a phenomenon of very rare occurrence we should be thrilled by it and aroused to curiosity and special observation and interest. The child's knowledge of the sexuality of nature should be as much a matter of fact as any other knowledge, and the mystery of it should be presented to him as a sublime and beautiful mystery, creating an impression he cannot wholly escape from when he finds himself caught in the vortex of his own adulthood. IX AMPHIBIOUS LIFE To the parents who desire to lead the child's mind through a long sequence of thought from the lower to the higher life, the amphibian affords an easy step in this ascending scale. And among amphibians that familiar and picturesque harbinger of spring, the frog, and his cousin the friendly toad, are the best adapted. Children are always interested in frogs because they jump so well. This suggests a starting-point for making their closer acquaintance. Why do they jump so well? It is because of their long hind legs. A little watching of either frog or toad will show exactly how the legs are used and wherein they differ from, and also resemble, the child's own legs. The little hands of the frog and toad, their way of sitting, leaning on their short arms, their eagerness to snap up a tempting fly, the queer tongue fastened the other way round from ours, and its lightning-like speed which is a result of this same position in the mouth,--a hundred interesting things can be learned about the toads and frogs. Toads are very easily tamed, and make most amusing as well as useful pets if there is a garden to be protected from marauding insects. They generally have a hole or corner to which they come home regularly at night, and with a little patience can be so tamed that they will take food, of living insect or even of scraps of meat, from the child's hand. Their power to gormandize seems unlimited, and the number of insects they can swallow without protest is almost incredible. They will keep a small garden quite free from slugs and other pests. They have no bad habits, do not bark at night, or chase cats, or bite, or steal, or insist upon coming into the house, or scratch up the flower-beds. Some accuse them of causing warts, but this is not true. When handled, they sometimes give forth an acrid liquid from the skin, which stings the mouths of tormenting dogs and smears meddling fingers. But this, though unpleasant, does no harm. Many people have handled toads freely and never had a wart; many others who have never touched a toad have had many warts. The toad may be ugly to look at, but that is not his fault. To many, he is more comical than ugly, and no creature has more beautiful eyes than this same homely toad. He is one of the most useful of animals, and should never be killed or ill treated. The frog is less familiar to us than the toad, living as he does in the water or in wet places. Boys often take delight in killing him, having theories of the terrible influence he exercises in the affairs of man. He is as harmless as the toad and of value in keeping down insect pests, since these are also his food. In the spring of the year, the frogs and toads will be heard chirping, the frog in particular sometimes filling the night with his din. The earliest of these voices comes from the smaller green frogs, or "peepers," as they are often called because of the peeping noise they make. The deep bass croak comes from the large bull-frog, so named from his size and not from his sex, for there are female bull-frogs. When the frogs begin to peep, the children will enjoy making an excursion in quest of frogs' eggs. These will be found in any pond where the voice of the frog is heard, and can be taken with a long-handled dipper or by wading,--the latter practice to be cautiously indulged in northern latitudes at this time of year, as the water may yet be very cold. The eggs are gray, spherical, about as large as sweet-pea seeds, and have a black spot on one side. They are found embedded many together in a colorless jelly-like substance. The egg-mass should be handled carefully and put whole into a jar or pail of water and thus carried home. It should not stand with the sun shining directly on it, and when the water is changed, every other day, that which is used should be of about the same temperature as that removed. Water drawn cold from the pipes will sometimes kill the eggs. If all goes well, in a few days the eggs will hatch. Out of them will hatch, not frogs, but tadpoles, or pollywogs, as they are also called. Everyone likes to watch a tadpole--certainly every child does. As soon as the eggs hatch, the surrounding jelly substance may be thrown away, merely as a matter of convenience. Its use is to protect the eggs and to afford the first food for the tadpole. If left too long in the water, it becomes broken up, discolored and unpleasant. The tadpoles should have fresh water every day or two, care again being exercised not to use it too cold, and they must be fed. They will eat almost anything, crumbs of crackers or bread, and bits of raw meat or fish being very acceptable. If they are well fed on meat or fish, they will grow faster and change earlier into frogs. Indeed, by underfeeding tadpoles a person can keep them a whole year from undergoing the changes they would have normally undergone in a few weeks. The large bull-frog tadpoles naturally take two years to develop, though a very nutritious diet may possibly hasten them. [Illustration: TADPOLES AT DIFFERENT STAGES OF GROWTH] The tadpole has very small eyes, a very small mouth, and tiny gill openings like a fish. Indeed, so far as its life at this stage is concerned, to all intents and purposes it is a fish. It cannot live out of the water, it breathes by gills, it swims by its tail, but it has no fins. It wiggles about the jar or tank in a very lively way, and ought to have water weeds or stones to hide under, and pebbles or gravel in the bottom of the receptacle. The ordinary tadpole, if well fed, astonishes and delights his young keepers in a few days by putting forth a pair of tiny hind legs, which generally trail behind him when he swims, though he often kicks with them, perhaps for exercise. He grows larger and his legs longer, and one day a row of fingers may be seen peeping out of his gill slit, as though out of an armhole, and then he will thrust out a forearm, then another from the other gill slit. After this, changes are rapid, and his keepers should put a stone or some firm object in the water, reaching above the surface, so that he can climb up into the air; for now his lungs are rapidly forming, and soon he can no longer breathe by gills. At this stage, his tail begins to disappear. It does not fall off, as some think, but its substance is absorbed into his body until no tail is left. Finally, his head changes its shape, his baby mouth is replaced by a wide frog mouth, his eyes stand out with projecting lids, his ear-plates showing back of them, and we have a full-grown frog. To the child who understands the origin of the fish eggs a few questions which he can easily answer himself will be enough to call attention to the important differences, and also to deepen the impression of the unity of life as expressed in flower, fish, and frog. The ova of the frog develop in an ovary exactly as do the ova of a fish; they develop in the same way and at the maturity of the animal. The fertilizing cells develop like those of the fish. In both cases, the reproductive elements are laid, shed, or born, when the time comes. Before the eggs of the frogs and toads are laid they have no albuminous covering. The moisture that envelops them swells up into the jelly-like mass upon coming in contact with water. There are important differences between the frog and the fish. The frog is a more complex animal and, so to speak, more difficult to create, and it lays fewer eggs. Since there are fewer eggs they must be more carefully fertilized; that is, the fertilizing material must be sure to come in contact with all of them. Consequently at the moment when the eggs are finding their way into the water they are fertilized; not within the female body, but just as they are leaving it. The child accustomed to notice what he sees will observe the paired frogs in the pond. He can be told that they take this position just before the eggs are laid so that every egg will surely be fertilized. In the amphibious animals the relation of the two parents is closer than in the fishes, but yet there is no union between them, that appearing only when it is necessary. The stern law of necessity governing every step of the reproductive function may be made very impressive to the young mind; also _the reign of law_ throughout life. To explain frankly, simply, and scientifically such phenomena as that of the paired frogs will tend to rob them of dangerous interest. Not to speak of them will not prevent the child's seeing them, and his imagination may foster much less wholesome thoughts. There are frogs and toads that care for their young, but parental affection in this form of life is rare. The eggs are laid in a favorable spot, and then left. Toads as well as frogs lay their eggs in the water. The instinct of the toad leads it to seek the water at the egg-laying season, as its tadpole, like that of the frog, can live only in the water. At other seasons of the year the toad does not enter the water. Frogs' eggs are laid in compact masses, while toads' eggs are laid in strings or ropes; and in this way they can be recognized, though after they have once hatched the tadpoles of both are so much alike that they cannot be told apart. Sometimes the children will be disappointed because the tadpole does not change into a frog nor yet into a toad. It gets its four legs but does not lose its tail; it never loses its tail. In short, it is not a frog or a toad, but a salamander or water-lizard, which lays eggs similar to those of the frog, and whose young upon first hatching look very much like young tadpoles. If eggs are found in a pond where frogs are not heard or seen, they will almost always turn out to be the eggs of a salamander. X THE BIRD From the flower to the bird is a step easily taken if the parent prefers to omit the intermediate steps, or, after the story of the bird has been told, the stories of fish and frog can follow as occasion offers, instead of preceding it. The bird is peculiarly valuable in teaching the origin of life to the child, since in it we have such highly developed home and family instincts, the father bearing his share of the burden, illustrations of which are rare in the lower forms of life. As everywhere else, the best starting-point is with the life and interests of the bird itself, and for this caged birds are far better than the free ones, even though they may be only the sparrows and pigeons of the city streets. The flight of birds is that which particularly interests children as well as every one else. Birds will soon learn to come to a place where they are fed regularly; and the style of flight, depending upon the size and shape of the wing as well as the shape of the bird's body, is a very interesting study. Many a country child knows the common birds by their flight even when the bird is too far away and moving too fast to be distinctly seen. What he generally does not think of is _why_ the bird has this peculiar flight, and to have his attention called to it may increase his interest in watching the living bird. Whatever increases the boy's interest in the live bird tends to decrease his desire to make it a dead bird; and the numerous good bird-books, as well as the substitution in so many cases of the camera for the gun, has tended to preserve the lives of the birds and to create a sentiment in favor of their preservation. If the young child is taught to watch the birds and care for them, he will not often, when older, thirst to take their lives. While the flight of the bird may engage the first interest of the child, its manner of eating and drinking is worth attention, and the nature of its food is of the greatest importance. The shape of the bird's beak will decide, at least in a general way, the kind of food it eats; and a little study of birds will convince any one that all birds are useful to the agriculturist, either as destroyers of noxious insects or of weed seeds. While some birds swallow the seeds whole and pass them again unharmed, thus spreading the plant, others crack the seed coat and eat the contents, which of course destroys the seed. Even where the birds are the means of sowing seeds they do more good than harm; for the seeds thus sown are not often harmful, and those same birds destroy a vast number of noxious insects. Even owls and hawks, by destroying mice in the farmer's fields, do him a service that much more than compensates for the loss of an occasional chicken. While the birds are of inestimable value to the farmer and to any one who has a garden, their influence on our lives in another direction is also very great, as difficult to estimate perhaps, as that of flowers. Who can doubt that these little brothers of the air are one of the most civilizing and elevating factors in man's daily life? Their song, their flight, their thousand and one charming or entertaining habits, their strong expression of personality, their poetical and mysterious comings and goings, appeal powerfully to the higher imagination. The migration of birds is alone enough to fill the mind with enchanting dreams. To know that every night in late summer and in autumn there is a stream of birds moving high in the air along the line of the sea-coast and of the great valleys is enough to awaken fancy. This winged procession moving along its aerial highway is made of the small and timid birds that dare not fly by day for fear of hawks and other enemies; they may be as high as three miles above the surface of the earth, their height being estimated by watching them through the telescope as they cross the surface of the moon. Imagine looking through the telescope at the face of the full moon some night and seeing an endless procession of little birds speeding across its shining face! The amazing power of birds to see and hear, and, most interesting of all, their nest-building habits are calculated to arouse the wonder and admiration of every observer. What child would not watch with intense interest the bringing of the straws or other materials, and the deft weaving of them into the home which is presently to receive the precious eggs? Even the city sparrow may here be a boon to the mother. Sufficiently encouraged, it will accommodatingly build almost anywhere. The child who knows the story of fish life and frog life will need little telling here, and that is one argument in favor of taking all the gradual steps from flower to bird. By this time the main ideas are firmly lodged, the child will readily draw his own conclusions as to the rest; but there are one or two facts connected with the origin of the bird which are of great value in fixing the idea of _necessity_ which is at the foundation of all reproductive phenomena. Everything is as it is because it is necessary that it should be so. In the frog the higher development made necessary greater economy in the production of the egg and the fertilizing cell, and this economy of material necessitated the more certain fertilization of the egg. In the bird a great step upwards has been taken. Here we have something much more complex in every way. The frog was cold-blooded, comparatively sluggish, and comparatively simple in structure. The bird is warm-blooded, intensely active, and very much more complex both in bodily structure and in mind development. Here the reproductive activity is yet more economically conducted, and instead of thirty or more eggs, the bird produces often not more than six in a season, and even a smaller number if it is single-brooded, some eagles, for instance, rearing only two young in a season. Naturally these few eggs must be very carefully protected. Since they are not laid in the yielding medium of water, they cannot have so soft a covering as the eggs of the fish or frog, but are enclosed in a hard shell. This shell must of course be formed before the egg is laid, and the egg must be fertilized before the hard shell encloses it and thus makes forever impossible the entrance of the fertilizing cell. The ovaries of the bird are in the small of the back close to the backbone, and there is a tube called the oviduct or egg-duct, leading from the ovary down to the lower end of the intestine, which it enters. There is no separate opening for the oviduct into the outer world. There are two ovaries, with their oviducts, in the young bird, but these are so small that it is very difficult indeed to find them. As the bird approaches maturity, one ovary and its oviduct enlarge, and the ova, which develop from the inside of the ovary just as the ovule develops inside the flower ovary, also become large. Although the bird is born with two ovaries, but one, usually, develops, generally the one on the left side. When the bird comes to maturity, there is born in it a yearning for home and offspring. As the eggs develop, the bird turns to the nest and to the mate who is to share with her all this beautiful life. When the mate has been chosen, both prepare the nest to receive the eggs, which will soon be ready. It is during this period that the fertilizing fluid is placed in the lower end of the egg-duct, whence the fertilizing cells, by their power of motion, quickly make their way to the egg, which has just begun its journey down the oviduct and is as yet without a shell. The shell-less egg is well known to most country children, as hens often lay one; and this will always happen where there is not lime enough in the food of the poultry. After the egg is fertilized it continues its slow journey down the oviduct, which enlarges to accommodate it. At first the egg consists of the yolk alone. This grows to its full size before it leaves the ovary. The yolk in short _is_ the egg. But there is not enough food material in it for the development of the bird, so as it passes down the egg-duct it becomes coated by the so-called "white" of the egg, which is a substance secreted from the lining of the egg-duct and is not alive, as is a certain part of the yolk. It is merely stored-up food like that in the morning-glory seed, for this egg is the seed of the bird. At the lower end of the egg-duct there is secreted a limy liquid which covers the shell-less egg and hardens, making the shell. So finally the fertilized egg has its shell and is ready to be laid. When this time comes, the bird seeks her nest, and the egg is laid or born, and lies warm and living, like a jewel in the nest. It is hardly necessary to add that the fertilizing cells in the male bird have an origin similar to that of the ova. The testicles and their ducts are too small to be easily seen in the young bird and in the winter-time, but can be seen during reproductive activity. The male bird can usually be told from the female by differences in color and plumage, but where this is not the case the two sexes cannot be told apart without actually killing and dissecting the birds, so very simple are the generative organs. The ripening of the reproductive elements in the bird occurs in the spring of the year, and is always with a few exceptions accompanied by the instinct of nest-making. The birds instinctively and joyfully prepare the home for their young at this time, both parents joining to make the pretty structure. With the child the higher emotions which always accompany reproductive activity in the bird life should be kept ever prominent,--the affection between the parents, their care and love for each other, the care and love for the helpless young, their happiness in this duty as shown in their song and bright colors. Unlike the fish and the frog, the bird cannot develop unless the egg is kept warm, and after it hatches the young bird cannot take care of itself for several weeks. It must be carefully nurtured, and finally even taught how to fly and find its food. The maternal hen can be a treasure to the mother seeking to impress the lesson of love and care; the only defect is the indifference of the father, which is in marked contrast to the interest shown by other birds, though there are many proofs that the cock is not without parental love, as where young chicks have been abandoned he has been known to rear them. The love of both the birds for their helpless young, and their devotion to each other, can be impressed on the young mind in many a picture of beauty. Many birds pair for life, returning to the same nest year after year. Nor should the instruction fail to impress upon the young mind the advance of love and tenderness on the parent for the offspring as we ascend the scale of life. The flowers, the fishes, the frogs, entrust their offspring to the care of Mother Nature; the birds cannot do this. The mother and the father of the helpless little creatures take deep joy in sacrificing their own freedom and strength and time to this loving duty. A bird will even lose its life for its young, trying to drive off an enemy; and every one knows how dangerous it is to approach the nest of any large bird, eagles and even cranes sometimes killing men and boys who try to rob them of their young. The plumage of birds is a pretty subject of study. The wonderful way in which feathers are adapted to their use, in keeping the bird warm without greatly increasing its weight or impeding its flight, may be made very interesting; also their beauty both of structure and color, and the fact that at maturity the plumage often undergoes remarkable changes. Young birds are colored like the mother. The brilliant male of the Baltimore oriole gets his bright dress at maturity, but until that time he is as soberly clad as his quiet little mother. The inheritance of the young bird from its father should be enlarged upon. At the beginning, though the male birds resemble the mother in appearance, at maturity they wake up to the characteristics of their father. Then the brilliant colors begin to play over their feathers--his colors. Then the song trembles from their throats--his song; and the beautiful creatures might sing as their wonderful wings flash through the air, "All this loveliness I owe to my father: it is from him I received this glorious heritage of beauty and song." The child can learn the terrible consequences to the birds of their feathers being taken as ornaments by human beings. The children can be told that the plumage is most beautiful at the mating and nesting season, and that thousands of birds, both male and female, are slain then, that the eggs and young birds consequently die, and that some species have been almost if not quite exterminated in this cruel way. The Audubon societies are organized for the purpose of instructing young people about the birds and getting their coöperation in opposing this needless slaughter. Some of these organizations are extremely interesting in their field and lecture work on birds; every neighborhood could have its Audubon society, to the great pleasure and profit of the members as well as to the profit of the birds. Where the mother desires to pass directly from the flower to the bird, this can be well done by comparing the two, so far as their generative processes are concerned, at every step. She can remind the little one of how the flower seed is treasured in the ovary until it is able to go out into the big world, and can then tell him that the wonderful seed of the bird, which we call the egg, is treasured in the same way; this to be followed by the story of the care needed by the bird's egg after it is born,--how it cannot be left to shift for itself, but must be watched over and kept warm by its loving little parents until it is fit to leave the shell, how it then breaks its prison and comes forth so weak and helpless to be yet further loved and cared for and taught by its faithful parents. The question is often asked, should not the story of motherhood precede that of fatherhood in all this early teaching? Up to a certain point it may be well, and the story of the life and development of the egg can be told to young children, with the father-bird merely an æsthetic factor, so to speak. His care of the young, and protection of the mother-bird can be dilated upon without going any farther. This is a course, however, which it will not be wise to follow too long, particularly with boys, whose interest will be greater when they know that the father too has a vital interest in the life of his offspring. Moreover, there is a certain spiritual value in connecting the equal need and responsibility of both parents in the creation of their offspring. The child then knows that he has the whole truth, and half truths are never quite safe. If the child knows the story of flower, fish, and frog life, he will draw his own conclusions about the birds, and it will be wiser frankly to tell him this part of the story. If he knows nothing of the earlier work, and the mother begins with the young birds in the nest, according to his age and surroundings he should be told more or less, the mother always remembering that if she defers too long somebody may anticipate her with the kind of information she particularly desires to avoid. Another question often asked concerning the bird is, "Would the egg be laid if it were not fertilized?" It might be or it might not. In all forms of life the sensitive reproductive system responds with peculiar readiness to its environment. In birds if it does not receive the stimulus that comes from mating, the ova may not develop at all, but remain small and attached to the ovary. Or, a few may be completed and laid, as is often seen in the case of caged female canaries. But these eggs of course could never hatch. They are perfect so far as the ovum is concerned, but lacking fertilization they cannot continue their development. Another question often asked, and of peculiar meaning, is, "If the reproductive system be not exercised, will it not perish for lack of exercise?" The latest word of science on this subject is that it will not, either in the bird or elsewhere. In a healthy organism it can safely remain inoperative with the certainty of becoming active at a later period if then it receive the normal stimulus. The lessons to be learned from the birds are many. From them can be answered all questions, for now we have passed that most difficult of all points, the relation of father to child in the animal world, and everything else can be explained through the knowledge already gained. The well-taught child will recognize the justice and necessity for the existing processes of life. He will realize their deep meaning, their far-reaching influence, and their tremendous importance in preserving upon the earth the multitudes of living forms that inhabit it. The flower and the bird are the two most important helps in imparting the facts concerning the renewal of life throughout nature. XI THE MAMMAL The mother who has conducted the child through the various life forms up to the mammal will not be likely to wish to stop there. Having gone thus far, it will be easy to continue and reveal to the child the wonderful life that yet remains. The question is often asked, whether country children are not much more likely to learn these truths naturally and without instruction than city children. The answer is that they are more likely to learn the facts, but knowing the facts is by no means understanding the subject; and whether knowledge of the facts is good or bad for the child depends entirely upon the impression it makes upon him. Undoubtedly the country child is in a better position to receive instruction, but whether this instruction tends to refine his feelings and elevate his heart depends altogether upon how it is given. Probably the average country boy has no more spiritual conception of the matter than the average city boy, though he may have a more wholesome and, so to speak, utilitarian thought of it. His interest at least reaches out to results, for the successful multiplication of the stock on the farm may be a matter of vital importance to him. The extension of knowledge from the bird to the mammal may be made through the medium of the family pets. Fido, puss, the pet rabbits, or squirrels may serve to elucidate the subject. Indeed, at this stage the well-instructed child himself will be ready to give all the essential facts, and will feel free to ask questions concerning the facts he does not understand. If he has traced the continuity of the egg from the flower to the bird it will not be difficult for him to realize that even the higher animal has its origin in the same way. The mother can very reverently explain to him that the cat too has ovaries; that from these develop ova which are few in number and need very special care. They cannot be laid in a nest like the bird's egg. They are very tiny, no larger than the head of a small pin, and they have no hard shell. It is their destiny to remain in the oviduct and develop. That is, instead of being born like the bird's egg and then being hatched, these eggs first develop and afterwards are born. But if not fertilized they would not continue to develop. The cat has two ovaries, which develop at maturity and ripen the ova, and these pass into the oviducts, which are tubes like the oviducts of the bird. Here the egg remains a certain length of time, and then if it is not fertilized it is passed away; but if it is fertilized a marvellous change takes place in this tiny cell: it remains within the oviduct and is there supplied with nourishment by blood-vessels essentially as the flower seed is supplied with food from the sap. Generally three or five of these ova develop at the same time, some in one oviduct, some in the other. When these tiny eggs have developed into kittens strong enough and perfect enough to make entrance into the world safe, they are born just as the egg is born. Unlike the oviduct of the bird, which opens into the intestine, these ducts unite just before the end, and have separate openings of their own. As soon as the young are born the mother begins to care for them. For several weeks they depend upon the milk she secretes for their food, and upon her constant care and loving watchfulness for their life. The thought of parental love and care should be much more strongly emphasized at every step than the mere physical facts, though it is necessary that they too be clearly comprehended. The sacrifice of the parent for the child is one of the most universal and unselfish facts of life, and many stories illustrating it can be collected and told. It is not necessary to tell them as obviously pointing a moral, yet they should be told as dramatically and interestingly as possible, that the child may get a strong impression of this great force. Among mammals it is true, (but this need not be dwelt upon with the child,) that many males pay no attention to their offspring; though some, as the cattle, defend the females and young if a herd is attacked by savage animals, by putting them in the centre and themselves forming a circle about them. It is the mother love and care, however, which are here most prominent; but the child who knows the facts concerning paternity should not be allowed to forget the great factor of inheritance, and that the offspring gets its characteristics from the father as well as from the mother. There is only one more step to be taken in the _modus operandi_ of reproduction, and that is in the higher mammal, where the ovum passes down through a slender oviduct into an enlarged chamber or womb, where it remains a certain length of time, finally if unfertilized, to pass away unnoticed; if fertilized, to develop into a young animal which in time will be born helpless and dependent upon the love and care of the mother. In some of the higher mammals, as the sheep and the goat, there are generally two ova developed in the womb at the same time; that is, twins are born. In the larger ones, as the horse and the cow, but one ovum generally develops, though the development of two is not uncommon. As a result of these teachings, which are not formal like school work, but given as opportunity offers and in as interesting and outreaching a way as possible, the child learns that all life develops in the same way. That all life, even human, starts as a tiny ovum. That these tiny ova are produced in every female by a special tissue called the ovary, which develops at maturity when the eggs begin to ripen; that if the ova are not fertilized they do not develop; if they are fertilized they develop into an individual like the parent, though having personal peculiarities of its own. The fertilizing cells are produced in every male from a special tissue, which greatly develops at maturity when the fertilizing cells are matured and are capable of uniting with the ovum to produce the new being. Along with these necessarily material facts the youth is firmly impressed with the high office of this great function, his thoughts concerning it are honest and clear, and he understands in a natural way the necessity for respecting it and guarding it for the good of those who are to follow. The essential facts the child can well learn before his own maturity. They seem to him matter-of-fact, like any other phenomena of life. He does not need to brood over an incomprehensible and veiled mystery, and the whole subject cannot fail to have a broader significance, a deeper, wider meaning, a purer influence than it could have if only the physiological facts relating to his own life came to his knowledge. But should one wait for all these intermediate steps before telling the facts of human life? That perhaps depends upon the temperament and circumstances of the parent and the needs of the child. It does not matter much whether the steps are taken consecutively or not, so long as the child gets a clear idea of the main facts and connects them in his mind with similar phenomena in all forms of life. Nor is a great store of knowledge on the part of the parent necessary. Each will tell in his own way such facts as he knows, keeping only in mind that he is to impress the child with the wonder and beauty of reproduction as a means to an end, and as a universal law working essentially alike in every living thing. There is something deeper than mere knowing, which the parent wishes to kindle, like a sacred fire which can never be extinguished, in the soul of his child. That is, a high reverence for the noble mystery of human life in its inception, and a deep love for his parents and a profound faith in them, such a love and reverence that any impulse to subvert the forces of his own life may be met with successful resistance. The boy who hears from his mother's lips his first knowledge of his own origin, who learns from her the full meaning of maternity, its sacrifices and suffering and the great love that gladly endures all, suffers all, for the sake of the precious child who is to come to her arms,--for the young life, his life, that she is to guide and cherish,--can never enshrine a debased image of womanhood in his heart of hearts. With some children--and some mothers--this might well be the child's first introduction to the subject. Afterwards he could be shown the flower and its seeds, the fish and its eggs, the egg of the bird, and somewhat later introduced to the pollen of the flower as necessary to the completing of the wonderful transformation. Nor will it be difficult in these growing years to instil into the boy the best elements of chivalry which shall make him a champion for his mother's sex. He ought to be trained to a certain respect and courtesy toward girls and women as he grows older, by many devices in the home life which will suggest themselves to any mother. A feeling of protection for motherhood can be fostered in the boy through his relations with the lower animals; many a one has had the truth impressed upon him by his mother's admonition not to handle kitty roughly or chase her about too much, as she is carrying under her heart the burden of new life. Keeping and caring for pets may be a great education to the growing boy. It interests him in animal life, gives him occupation at home; and in breeding his pigeons, rabbits, or squirrels his interest in obtaining good specimens may be an open door to instruction of inestimable value far beyond pigeons and rabbits. Again, the boy's pet may by some mothers be found an easy introduction to the story of the development of the new life, the main stress being laid upon the care of the little mother, who must be treated with special kindness and consideration, and must be well fed. Some mothers encourage the children to save a little of their own milk and cream for pussy at this time, thus conveying the impression that some sacrifice of their own comfort is due to the mother who is bearing this extra burden of life. If the child is curious, the mother can tell him so sacredly the principal physiological facts that he will go from her feeling as little inclination to speak carelessly of what he has heard as he would feel like shouting his prayers aloud in the street. It will naturally occur to the mother to connect this whole subject closely with the religious thought of the child; and where this is done simply and without theology, but as an expression of the great divine love and foresight that passes like a golden thread through every form of living creature, it may be exceedingly beautiful and exceedingly helpful. It is now time to answer the question, "What is to be done with the older child who has received little or no preliminary instruction?" From eleven to fourteen the boy can be told the facts he needs to know with as much preparatory flower and animal studies as can be made interesting to him. Everything will depend upon his temperament and the kind of information he may have already received. He may be interested; the chances are he will not be, or at least will pretend he is not. In such a case he must be made to listen, and some such preliminary as the following will generally attain the required result. "There are some things that every man must understand rightly. I want to be sure you understand them, so that you may know the true from the false, the right from the wrong, and will not show yourself ignorant before the world." Generally to be seriously called a man at this age, or invited to enter the domain of the man, will conquer, and he will listen even though he may pretend not to. It often happens that the boy entering the "contrary age" wants above all things to know, and yet is ashamed to listen. It is generally safer to talk to the boy at this time than to rely wholly upon books to be read by him. Give him the books by all means but talk them over with him, supplementing them in any way that seems best. It may be better for the father to talk to the hitherto uninstructed lad at this age, but where this is not possible then the mother should see that the boy has the information he needs, in the most outreaching form she can bestow it, trying to make him realize the universality of the truth, the fact that every living thing is subject to essentially the same sex laws. It is best for him to feel that both parents understand and are interested in this side of his development, and the mother, even though the father gives the instruction, may be able to show her son that she too knows and cares. It will be much less difficult as a rule for the mother to talk to the girl at this age, and of course there will be many children, both boys and girls, with whom no difficulty will be encountered. With older children, those perhaps from fourteen to eighteen, yet other methods may need to be pursued. Many youths can be approached without difficulty, and what they need to know can be explained directly to them. Whether this is so or not often depends quite as much on the parent as on the child. Where the mother feels that a direct appeal to the youth would be injudicious she can sometimes gain his interest by indirect methods. If there are younger children she can introduce the subject by saying that she is anxious to have the children instructed properly in this subject, and that she relies upon him to assist her in various ways, and particularly by always understanding what she is doing, and adding the weight of his influence as an older brother. She can then consult him as to the best way of going to work, explaining about the botany work and what she hopes to gain by using it, all the time taking for granted that he knows everything. If he is interested, she can explain all to him in this way, opening the door to certain other information she must be sure that he has. Of course she may be able to relegate all this instruction to the child's father, but if for any reason this is not possible, the boy must get his help either directly or indirectly from her; and in any case if it is possible to associate him with her in the task of enlightening and helping his younger brothers it may give a certain definiteness of thought on the subject, and, what is of more importance, a sense of responsibility in regard to it. It will also help him to a realization of the universal nature of the manifestation of this side of life. By occasional appeals to his sympathy and help as time goes on and getting him to read certain books in order to help her to decide whether they would help the others, she may be able to do him an incalculable benefit. Even though he may argue against instruction, that will give an opportunity to put in his way sources of knowledge, and if he does not feel inclined to read the books recommended they can be left in his way where he can read them without being detected, which he will be apt to do. Generally young people are eager for instruction, though where they have been neglected and have formed false ideas and ideals they sometimes become perverse, particularly toward members of their own family. This may often be due to fear in one form or another, and the wise parent will leave no means untried to give the youth somehow the help he needs. Many parents feel it wise to give the youth some good book on the subject suited to his age, a book of his own which he can keep in his room to consult whenever he is puzzled or doubtful about his rule of conduct. XII VIGILANCE That the facts concerning the normal reproductive life throughout nature can be presented in such a way as to create a worthy image in the mind of the learner there can be no doubt. The question naturally arises, "Is this enough to insure morality and personal purity in the youth?" Few knowing the tendency of the age would hesitate to say most emphatically that it is not enough. The end in view being to prepare the young soul for the great battle of life, to put upon it the armor of a knight which shall be borne untarnished, the first instruction concerning the facts of the reproductive life may well be impersonal, poetical, beautiful, filling the mind with sentiment,--not sentimentality,--so that the mental vision of this side of life shall be one worthy of the glorious mind of man. To keep the mind of the child wisely impressed with the beauty, the achievements, of the great reproductive force in nature, which is directly responsible for every living thing on the earth, is to help immeasurably toward branding a high instead of a low ideal on his soul,--an ideal which he cannot lose when he reaches the great climax that transforms him into an adult capable of reproducing his kind, and when whatever most powerfully influences him will become a determining factor in the administration of his whole after life. Side by side, however, with this illumination of nature's methods should go the most careful training and watchfulness in the care of the child's own person,--not that he need connect the two in the least. Later, of course, he will, and should as time goes on, have the most careful instruction concerning his own body and its functions. There are a few simple observances that every human being should learn from childhood, and learn so thoroughly and so fix as a matter of habit, that he can never break away from them. At first the parent attends to the child's wants, later the child must care for himself; and while he ought not to be burdened with too much thought of his body, yet there are a few simple rules of hygiene which he should follow as a matter of habit, and there is one subject upon which he should be most carefully instructed,--that is, maintaining the sexual purity of his body. He should be taught from the beginning to think of his body as the sacred temple of his soul, which it is a sin against nature and against God to defile. That the child's body be kept uncontaminated is one of the most priceless gifts his parents can bestow upon him; the value of this was so keenly felt in antiquity that at a certain period of Greek supremacy the laws were most stringent concerning it, a youth sinning against himself being put to death. There seems to be a growing need of watchfulness over children in this respect; few who have not looked especially into the matter have any idea of the prevalence of harmful habits. Sex abuse has been called "the disease of civilization"; and where it takes firm root, it is exceedingly disastrous to the life of a nation, not only destroying, directly or indirectly, individuals, but so weakening the stock that the whole nation degenerates. The root of the difficulty perhaps lies in the low ideal of this age on that subject. Where the ideal is low there can be no hope of a high result. That the current theories which control the lives of the many in this direction are false is the conclusion of the best scientific work of the present times. Where these theories, however, have been bred into youth for generations, they may to an extent be true simply as a result of this breeding. Darwin in his "Descent of Man" says: "It is worthy of remark that a belief constantly inculcated during the early years of life, whilst the brain is impressible, appears to acquire almost the nature of an instinct; and the very essence of an instinct is that it is followed independently of reason." For the parent, then, to inculcate this quasi instinct against sex abuse in any form is to give the child the best armor he could possibly have; and if this could be done for generations, the instinct would not need such careful fostering, as it would be born more or less developed with the child. Every parent of a purely reared child is putting a stone in the foundation of prosperity for this wonderful new civilization, which will go on evolving, or die of decrepitude, just as its central dynamic force, the sex life of the people, finally decides. Sex immorality is, as every one knows, one of the signs of the approaching death of a nation. Few young mothers realize the great need of watchfulness against the formation of bad habits in even young children. And many make the mistake of supposing that with children instruction can take the place of watchfulness. During the early years of a child's life careful watching as well as careful teaching, is necessary. Nor does the social grade of the child bring immunity or the reverse. The mother who says to herself, "Oh, _my_ child would not," does not understand the nature of the problem. Anybody's child may innocently fall into this error, and every mother should equip herself with all the information necessary to guard against this most insidious of all foes and to meet it if it appears, realizing that watchfulness is necessary almost from the hour of birth,--even children in the cradle frequently needing attention in this respect. Every young mother should know that among a certain class of people, from whom her nurse will likely be drawn, there are many who have theories most pernicious to the welfare of the child, the nurse herself not infrequently, through ignorance perhaps, being guilty of initiating the babe into a course from which it will be most difficult for him ever to depart. It is not safe to take for granted that any child does not need a certain amount of watchfulness. The most highly organized, most "high strung" sensitive natures are among those most in danger, not only from forming unfortunate habits, but from their results. Watchfulness during the early years of the child's life, instruction in caring for himself, plenty of outdoor exercise, unstimulating food, sufficient sleep, the cold bath, agreeable occupation, abundant material for wholesome thought and imagination, will in most cases bring the child safely to the first great milestone in his life journey, the period of adolescence. As the child grows older he should be warned against certain dangers which may beset him from other vicious or ignorant children; and of course the child's temperament, his heredity, the weakness or strength of his desires in the direction of sense pleasures, and the amount of will-power he possesses will guide the parent in the nature and amount of such instruction. Some mothers whose children have strong animal instincts are afraid to instruct them on that account. Such children are in peculiar need of watchfulness and knowledge, and the right kind of instruction does not tend to waken the senses. Of course no child should be sent away to school without an impressive warning against certain habits all too prevalent among boys in boarding schools. Here it may be wise to let him know something of what he will be sure to see or hear, that he may not be taken unawares, puzzled and tempted by things which to him will seem not to have come within the experience of his parents if they said nothing to him about them. The boy warned by his parents of the falsity of the strange doctrines he may hear preached by these unguided youths will not readily be deluded. The pure but ignorant boy going for the first time into the new life of the school, looking up to the older boys with that peculiar veneration the younger boy almost always feels for the older, moved in his senses by what he hears and sees, may speedily forget such home warnings as seem vague and pointless, and he may yield himself to a course most disastrous to his future. How can it fail to be the duty of every parent to protect the child against the chance of making these fatal mistakes through ignorance? Young people cannot be kept wholly out of reach of temptation, nor would it be best for them if they could be. Far better is it so to strengthen the moral fibre that they can resist. From time to time there appears in our best publications an appeal from some noted educator for the better instruction of youth at home, and their almost universal plea is that the youth be told by the mother the facts needed to give him a reverence for womanhood. XIII THE TRANSFORMATION The most difficult problems of the educator are found in connection with changes which take place in the child at the age of adolescence or puberty. This age has never been so carefully and systematically studied as at the present time, and it is proving an unsuspected key for solving many puzzling problems of racial evolution as well as of individual development. Personally it is a time of tremendous stress,--physical, mental, and moral; the young person who escapes turmoil being the exception, not the rule. Certain of the physical changes which occur are familiar to all, but the deep meaning of these changes is less generally understood. The parent who has wisely guided the child to this critical period has done much, but it would be a mistake to suppose that all has now been done that can be done. The habits of self-reliance, self-control, and right thinking formed through the years of childhood will indeed help now. But there awakens for the first time a new force: the child is, in a literal as well as figurative sense, being born anew. At this new birth, which is sometimes very difficult, he enters into a hitherto unknown world of interests and feelings. While the change from child to adult may proceed as a gradual and placid unfolding in some individuals, in the great majority it advances with irregular and disturbing demonstrations. This great change takes place in girls generally at from thirteen to fifteen, and in boys a year or two later, though it is not completed for a period of five or six years. During this time the most profound alterations take place in nearly all parts of the body; the mind undergoes a similar metamorphosis, so that often the child so carefully watched from babyhood seems entirely superseded by a new being. This is preëminently the age of romance. It is the borderland where is fought the battle of individuality, and it is probable that at this time is decided in a very deep way what is to be the trend of the whole after life. There is at this period such susceptibility to impressions that there may be indelibly stamped mental images that are the exact opposite of those of childhood, the childish memory remaining as a thing apart and by itself,--a curious separation and continuation of two lines of ideas, which every one has perhaps experienced to some extent and on some subject. It is probable that impressions received now are of more importance in determining conduct than at any other period, or at least in determining it for a long period of years, the period when the individual makes his strongest impression upon the world. Reversion to the faith or the ideals of childhood, which so often occurs in old age, is of slight importance to society as compared to the influence of the individual when at the zenith of his powers. Consequently, it is of the utmost importance that the right thought and the high ideal be firmly implanted at this new birth. Undoubtedly the habits of childhood make impressions in the same direction more easily received, and where self-indulgence and gratification of the senses have been prominent, they will be sure to exert a tremendous power now, and _vice versa_. Thus a clear understanding of this period is of the utmost importance to whoever undertakes the guidance of youth. The central point about which everything now revolves is the coming to maturity of the sexual system. It is as absurd as it is harmful to ignore the fact that this is primarily what the change means, and that with the physical power to become a parent there normally appears, either initially or with greatly increased force, the sex appetite. This is normally true of both boys and girls, though the forces that have gone to make our present civilization have, at least in many cases, made the physiological sense cry subordinate in the girl, and occasionally this is also true of the boy. There is no period in the life of the human being when he so needs help in certain ways as now, and no time when it is so difficult to help him, as every youth now more than ever before affords an individual problem. One of the difficulties attending this period is the tendency to unsymmetrical growth. Oftentimes the body shoots up with amazing rapidity, this quick growth of bone and muscle drawing heavily on the whole system; parents recognize the condition by saying the child has outgrown his strength. He has often outgrown much more than this, for his intellect may not have been able to keep pace, and we not infrequently have the anomaly of an adult body with the mind of a child. No one is more conscious of this incongruity than the subject himself, whose anatomy seems to have run away with him. This rapid growth is generally marked by excessive development of some parts over others, so that the child becomes clumsy and awkward. If the subject is a boy, the sudden change in the size of his vocal chords often causes a distressing "breaking" of the voice which adds materially to the general sense of disharmony. Those who have not experienced this sudden and unsymmetrical development can have little idea of the trials of the young soul going through it, a suffering so great that suicide is often seriously contemplated as the only solution. And all this turmoil is kept within the heart of the sufferer. To the outsider the boy, the girl, is merely "cranky" or "contrary." If not constantly nagged at and reproved for his awkwardness at home, he is sure to have it ridiculed by his schoolmates, particularly by those of the opposite sex. He cannot help being round-shouldered and loose-jointed, with protruding shoulder-blades and awkward motions; and the pathos of it is, he thinks he must always remain so, an ugly failure and a laughing-stock to the community. The effect this has upon him will depend upon his temperament. Very sensitive and fine natures often instinctively seek to cover the real trouble by exaggerating the defects in every way possible,--making believe they do it all on purpose, and acting the clown and the ruffian, giving way to the irritability natural to the condition with a sort of reckless despair which is sure to be misunderstood and censured by those he loves best. When this stage is reached, it is easy for him to imagine himself a social outcast, a useless encumbrance that nobody loves, a clumsy dolt that nobody likes to have about. Again he may become sullen, morose, resentful, and suspicious toward all about him. Or, a timid nature may become more timid, shrinking, weak of will, and despondent concerning life in general; or the subject may show an exaggerated egotism which seeks by sheer intrusion of self to force everything else aside. In the course of a few years he grows out of these difficulties, but the suffering he underwent may have made such an impression upon his excessively sensitive nerve centres that he never entirely recovers from it, and may be controlled by it in ways he does not suspect all the rest of his life. It is needless to say that a large part of this suffering could be averted by knowledge on the part of the parents and of other adults with whom the youth comes in contact, as well as on the part of the youth himself. What he most needs in his "awkward age" is sympathy, patience, firmness, and instruction, and his physical defects should never be ridiculed. Perhaps nothing is more helpful to youth at this stage than to have its vagaries treated seriously. Wonderful dreams of future glory and accomplishment, remarkable theories of the universe, astounding schemes for impossible inventions, new Utopias, wild adventures, and at times even questionable escapades are the natural and luxurious growth of the newly stimulated imagination. They do no harm, and are a safety valve which should be understood. Honest sympathy, where sympathy is merited, will give weight to warning and disapproval, which would have no weight at all if the whole fabric of the imagination, which is so real and so precious to the imaginer, were condemned without discrimination. These dreams of youth are often the real stuff out of which the fabric of life is later to be woven, taking new forms it may be, but getting their inception there. Some one has said that if the facts could be known, the thought germs whence finally came the steam engine and the electric telegraph were probably conceived in the brain of an adolescent; and we know that poets are born at that age. Many of the dreams of the youth may seem fantastic and ridiculous, but if the adult can only remember that they are not so to the dreamer and that this is a phase through which he is passing,--a phase which in most cases will pass entirely, leaving only, so to speak, a glow behind,--he will be more sympathetic and thus more helpful. If he can also realize that these dreams of the youth are an expression on the highest plane of the creative instinct which is in a sense controlling his body, mind, and soul, these vagaries, far from being ridiculous, will be recognized as worthy of the deepest respect. Now, too, the parent who has won the full confidence of the child through confidential talks on sex matters can without difficulty instruct him in the meaning and control of the new forces that are at work upon him. The whole subject now changes. It becomes personal, and his thoughts are clouded by new problems and by the imperious demands of the body. According to the nature, inheritance, and previous habits of the youth these demands assert themselves. And now is the time of greatest danger from ignorance. Even though the boy has been well taught up to this age, if he is cast adrift now on the turbulent sea of desire and allowed to gather information from the sources all too available, there may occur a split between the thought of his childhood on this subject and the thought of his adulthood. If he is not allowed to drift, however, but given a chart and compass, the knowledge he has already of how to sail his ship will enable him to make straight for the right port, which he will have a good chance of reaching, no matter how stormy the seas he may have to traverse. With the right knowledge now, the idea and the ideal of his childhood may become the idea and the ideal of his manhood. If the child's thought of the subject has been unworthy, the danger of forever enshrining a wrong image in the soul of the adult is greater, and the difficulty of placing there the right one is enhanced. The outward signs of the girl's development are usually explained beforehand sufficiently to enable her properly to care for herself. It is unnecessary to add that this should always be done, as nothing is more unjust than to leave her in a state of ignorance where the natural expression of her maturity may fill her mind with fears which may affect her nervous system ever after, even if they do not lead her to do acts which may permanently impair her reproductive vitality, and injure her health in other ways. All that she needs to know about the proper care of her person should be told her in the most considerate yet explicit manner, as should whatever is told her upon any part of the subject. It is a mistake to be vague now. Whatever is told concerning the reproductive processes should be said with the greatest clearness, leaving no room for brooding and imagination. And here, too, the wise parent will take into account the phenomenon of desire, which, so far from being abnormal in the girl, is normal in the truest sense. It may not play an important part in her life at this time, and often it does not, but again it may. Nor is the girl of whom this latter is true in any sense less fine or less worthy; perhaps on the contrary she is the best product of her race. Nor should she be afraid or ashamed of her nature, but only helped to understand and take care of herself and of her powers. With the youth at this period the changes that fit him for his new place in the world are generally ignored. He does not know what is normal and what abnormal in his physiological development, and is often the victim of groundless fears that use up his strength or send him in despair to seek assistance from the most easily available sources of information, those baleful writings and despicable quack practitioners everywhere soliciting and alarming youth, and whose career forms one of the saddest commentaries on the state of our civilization. The young man should know the truth about himself. He should understand the vast range of the change that is taking place in him, and that no two individuals necessarily develop just alike, either physically or mentally; and he should understand what are its normal phenomena, and how without fear to recognize and control deviations from them. Many parents direct the boy to go at once to the family physician if he is troubled or puzzled in any way. A few moments' talk with a wise doctor may save much useless worry. The more nervous and sensitive the boy at this time the more likely he will be to suffer from imagined troubles, and the greater his danger of falling into real ones. While the youth must know the physiological and anatomical facts and must know in a general way the consequences of vice, he will seldom be restrained or helped by the methods of the alarmist. It is far better that his mind at this time dwell upon the normal and noble side of sex life than on its abnormal and ignoble side. The value of diet, cold water, exercise, and occupation should be understood by the young people themselves, and also the tremendous value of thought in helping or hindering. Faith in one's power to win is the first requisite in any contest, and fortunately science to-day is saying what the inner heart of man must always have told him was true, that a chaste life is both possible and safe. Indeed the scientists of to-day declare it to be advantageous, heightening the power of the individual in all directions, and particularly at the growing age. Every parent has an ideal as to how he wishes his daughter to be treated by young men, and how he wishes her to conduct herself toward them. That this ideal be reached in the case of the daughter, it is necessary that the son be trained to a chivalry and respect for all women, which will make it impossible for him to take liberties with any woman. A right knowledge of the real meaning and the responsibilities and duties of their lives at this time would be a better safeguard for most young people than any amount of chaperonage. Nor will such training in any way lessen the joy of life, or the charms of courtship, but on the contrary, will enhance all that is most precious. When the youth goes finally into the real battle of life, into the world of business, of competition, and temptation, he will need all his fortitude and all his knowledge to guide him aright in his personal life. And then it is that he will begin to realize what his parents have really done for him, and to appreciate their forethought and care. Then, too, he not infrequently expresses in the strongest terms his gratitude to the mother, the father, who have guided his course safely over the dangerous shoals. The life battle of the youth who has been carefully instructed and preserved clean in mind and body is very different from that of him who has been weakened in will and perverted in mind from lack of such preservation; he knows that purity is both possible and good, and desires it above all things for his sons, both for their happiness and for their material success in life. Habits of thought and action have an incalculable influence upon the body as well as upon the mind; and here as everywhere else, the ideal, whether it be high or low, will control the destiny of the man. LIST OF BOOKS HELPFUL IN STUDYING PLANT AND ANIMAL LIFE BIBLIOGRAPHY I BOOKS HELPFUL IN STUDYING PLANT LIFE Andrews, Jane: Stories Mother Nature Told Her Children $0.50 Bailey, L. H.: Plant Breeding 0.75 Bass, Florence: Plant Life. Nature Stories for Young Readers 0.25 Dana, Mrs. William Starr (Frances T. Parsons): How to Know the Wild Flowers 2.00 Going, Maud: Field, Forest, and Wayside Flowers. Untechnical Studies for Unlearned Lovers of Nature 1.50 With the Wild Flowers, from Pussy Willow to Thistledown 1.00 With the Trees 1.00 Gray, Asa: School and Field Book of Botany 1.80 Huntington, Annie Oakes: Studies of Trees in Winter 2.50 Keeler, Harriet L.: Our Native Trees and How to Identify them 2.00 Laing, Mary E.: The Life of a Bean. For little children 0.15 Lounsberry, Alice: A Guide to the Trees 1.75 Lubbock, Sir John: Flowers, Fruits, and Leaves. Treats of fertilization of flowers, seed dispersal, leaves, stinging hairs, etc. 0.75 Morley, Margaret W.: Seed Babies. For young children, showing how plants come from seeds 0.25 Little Wanderers. For children, on the methods of seed dispersal 0.30 Flowers and Their Friends. Stories of plants and how they do their work of living 0.50 A Few Familiar Flowers. A book of methods for teaching beginning botany 0.75 Newell, Jane H.: Reader in Botany. Part I. From Seed to Leaf 0.60 Part II. From Flower to Fruit 0.60 Parsons, Frances Theodora (Mrs. W. S. Dana): According to Season. Talks about the flowers in the order of their appearance in the woods and fields 1.75 Rogers, Julia Ellen: The Tree Book. North American trees, uses, and culture 3.00 Roth, Filibert: First Book of Forestry 1.25 Spear, Mary A.: Leaves and Flowers. Botany for young learners, giving the principal botanical terms 0.25 Weed, Clarence M.: Seed Travellers. On seed dispersal; for older children 0.25 II BOOKS HELPFUL IN STUDYING ANIMAL LIFE American Humane Education Society: Publications, and "Our Dumb Animals," a magazine Per year $0.50 Bass, Florence: Animal Life. Nature Stories for Young Readers 0.35 Bateman, Rev. Gregory C.: Fresh Water Aquaria 1.40 Burroughs, John: Locusts and Wild Honey 1.25 Signs and Seasons 1.25 Wake Robin 1.25 Ways of Nature 1.50 Chapman, Frank M.: Handbook of Birds of Eastern North America 3.00 Comstock, Anna Botsford: Ways of the Six-Footed. Stories of Insect Life 0.40 Comstock, John Henry: Insect Life 1.75 Dixon, Charles: Birds' Nests 1.20 Eddy, Sarah J.: Friends and Helpers 0.60 Howard, Leland O.: The Insect Book 3.00 Hulbert, W. D.: Forest Neighbors. Life Stories of Wild Animals 1.50 Jackson, Gabrielle E.: The Adventures of Tommy Postoffice. The True Story of a Cat 0.75 Jackson, Helen Hunt: Cat Stories 2.00 Job, Herbert K.: Wild Wings. Adventures of a Camera Hunter among the larger Wild Birds of North America over Sea and Land 3.00 Jordan, David Starr (_Editor_): True Tales of Birds and Beasts 0.40 Keyser, Leander S.: Birds of the Rockies 1.50 Long, William J.: Ways of the Wood Folk 0.50 Wilderness Ways 0.45 Secrets of the Woods 0.50 Wood Folk at School 0.50 A Little Brother to the Bear, and Other Animal Stories 1.50 Mathews, F. Schuyler: Field Book of Wild Birds and Their Music 2.00 Familiar Life in Field and Forest. The Animals, Birds, Frogs, and Salamanders 1.75 Miller, Mary Rogers: The Brook Book 1.35 Morley, Margaret W.: Butterflies and Bees 0.60 The Insect Folk 0.45 A Song of Life 1.25 Life and Love 1.25 The Bee People 1.25 The Honey-Makers 1.25 Little Mitchell. The Story of a Squirrel 1.25 Our Four-Footed Friends. A Monthly Magazine. Per year 0.50 Patterson, Alice Jean: The Spinner Family. About Spiders 1.00 Repplier, Agnes: The Fireside Sphinx. A Book about Cats for Older Readers 2.00 Seton, Ernest Thompson: Animal Heroes 2.00 The Biography of a Grizzly 1.50 Lives of the Hunted 1.75 The Trail of the Sandhill Stag 1.50 Wild Animals I Have Known 2.00 Weed, Clarence M.: Stories of Insect Life Spring and Summer. First Series 0.25 Autumn. Second Series 0.30 Wheelock, Irene Grosvenor: Nestlings of Forest and Marsh 1.00 Winslow, Helen M.: Concerning Cats. Stories of Historical and Other Cats 1.50 Wood, Rev. Theodore: A Natural History of Birds, Fishes, etc. 1.25 Wright, Julia McNair: Seaside and Wayside. School reading books. 4 vols. Vol. I. 0.25 Vol. II. 0.35 Vol. III. 0.45 Vol. IV. 0.60 III MISCELLANEOUS Ellis, Havelock: Man and Woman. For those interested in the philosophical and scientific side of the subject. In the Contemporary Science Series 1.50 Geddes and Thompson: The Evolution of Sex. Contemporary Science Series 1.50 Hall, G. Stanley: Adolescence. Two volumes 7.50 Layard, Rev. E. B.: Religion in Boyhood. Chapter on How to Form Character. This book has an Introduction by the Rev. Endicott Peabody, head master of Groton School, Groton, Mass. 0.75 Lyttleton, Rev. the Hon. E.: Mothers and Sons 1.00 Training of the Young in Laws of Sex 1.00 Stall, Sylvanus, D.D.: What a Young Boy Ought to Know 1.00 What a Young Man Ought to Know 1.00 What a Young Husband Ought to Know 1.00 What a Man of Forty-five Ought to Know 1.00 Wood-Allen, Dr. Mary: What a Young Girl Ought to Know 1.00 What a Young Woman Ought to Know 1.00 What a Young Wife Ought to Know 1.00 Almost a Man 0.50 Almost a Woman 0.50 BY MISS MORLEY The Bee People _ILLUSTRATED BY THE AUTHOR_ Price $1.25 It is the story, told in most fascinating style, of the honey bee, how it is born, how it lives, how it gathers honey, and all about it, not omitting its sting. The bee is credited with powers of reasoning, and the troubles of the queen bee in retaining her throne are set forth in a delightfully fairy-story-like way which will win every child that reads it.--_The Times, Philadelphia._ Probably no branch of natural history is more interesting than the bee people, and when told by an appreciative student is doubly so. Miss Morley carries out the human idea suggested in the title; and the worker, the drone, the queen, and all the inmates of a hive are given a life-like personality. Many illustrations aid in telling the story, and many wonderful things concerning the habits of these little people are constantly revealed.--_The Detroit News Tribune._ * * * * * The Honey Makers _ILLUSTRATED BY THE AUTHOR_ Price $1.25 Unlike Miss Morley's other works, this book is intended for older readers. The first part of the book is devoted to the scientific exposition of the bee's structure, habits, etc., and it is surprising how much interest and humor the author has managed to infuse into the subject. The second part performs an original and valuable service to literature. To the bees more than to any other portion of the animal kingdom has attention been devoted by poets and thinkers seeking inspiration, and from this wealth of allusion and anecdote Miss Morley has culled the choicest and most striking parts. * * * * * A Song of Life _ILLUSTRATED BY THE AUTHOR AND ROBERT FORSYTH_ Price $1.25 With simple, beautiful phrases, with pure and admiring words to describe the process of life, and with scores of gracefully outlined forms of plant and bird and beast by a helpful artist, has this song of life been sung and illustrated to delight and instruct in the happiest way many a wondering child concerning the mystery of life.--_The Churchman, New York._ The plan of the work is novel, and the narrative is accurate and interesting to an unusual degree. Few writers on life's history give so much of it in a space so limited.--_The Nation, New York._ * * * * * Life and Love _ILLUSTRATED BY THE AUTHOR_ Price $1.25 Margaret Warner Morley has written in "Life and Love" a book which should be placed in the hands of every young man and woman. It is a fearless yet clean-minded study of the development of life and the relations thereof from the protoplasm to mankind. The work is logical, instructive, impressive. It should result in the innocence of knowledge, which is better than the innocence of ignorance. It is a pleasure to see a woman handling so delicate a topic so well. Miss Morley deserves thanks for doing it so impeccably. Even a prude can find nothing to carp at in the valuable little volume.--_Boston Journal._ It is an agreeable and useful little volume, explanatory of the mysteries of plant and animal life,--such a book as parents will do well to place in the hands of thoughtful, or, better still, of thoughtless children.--_Philadelphia Press._ * * * * * Little Mitchell THE STORY OF A MOUNTAIN SQUIRREL _ILLUSTRATED BY BRUCE HORSFALL_ Price $1.25 Miss Morley's own words give the best idea of this most engaging little book: "Baby Mitchell was an August squirrel. That is, he was born in the month of August. His pretty gray mother found a nice hole, high up in the crotch of a tall chestnut tree, for her babies' nest; and I know that she lined it with soft fur plucked from her own loving little breast,--for that is the way the squirrel mothers do. "This chestnut tree grew on the side of a steep mountain,--none other than Mount Mitchell, the highest mountain peak in all the eastern half of the United States. It is in North Carolina, where there are a great many beautiful mountains, but none of them more beautiful than Mount Mitchell, with the great forest trees on its slopes." A. C. McCLURG & CO., PUBLISHERS FOOTNOTES: [1] A great deal of confusion exists in many minds as to the origin of pollen and ovule. There seems to be a general and almost ineradicable impression that fertilization has something to do in creating the ovule. This is not so. The ovule is a part of every ovary just as the pollen is a part of every anther. Each will be produced whether they ever come together or not; only if they do not come together, both perish, while if they do, development of the ovule continues. 
32251	----	Note: Project Gutenberg also has an HTML version of this file which includes the original illustrations. See 32251-h.htm or 32251-h.zip: (http://www.gutenberg.org/files/32251/32251-h/32251-h.htm) or (http://www.gutenberg.org/files/32251/32251-h.zip) Transcriber's note: Text enclosed between equal signs was in bold face in the original (=bold=). APPLIED PHYSIOLOGY Including the Effects of Alcohol and Narcotics by FRANK OVERTON, A.M., M.D. Late House Surgeon to the City Hospital, New York Primary Grade New York Cincinnati Chicago American Book Company Copyright, 1898, 1910, by Frank Overton OV. PHYSIOL. (PRIM.) E-P 42 PREFACE This primary text-book of applied physiology follows a natural order of treatment. In each subject elementary anatomical facts are presented in a manner which impresses function rather than form, and from the form described derives the function. The facts and principles are then applied to everyday life. Anatomy and pure physiology make clear and fix hygienic points, while applied physiology lends interest to the otherwise dry facts of physiology and anatomy. From the great range of the science there are included only those subjects which are directly concerned in the growth and development of children. The value of a primary book depends largely upon the language used. In bringing the truths within the comprehension of children, the author has made sparing use of the complex sentence. He has made the sentences short and simple in form, and logical in arrangement. A child grasps new ideas mainly as they appeal directly to the senses. For this reason, physiological demonstrations are indispensable. Subjects for demonstrations are not given, because they cannot be performed by the children; but the teacher should make free use of the series given in the author's advanced physiology. Cuts and diagrams are inserted where they are needed to explain the text. They are taken from the author's _Applied Physiology, Intermediate Grade_. Each was chosen, not for artistic effect, but because of its fitness to illustrate a point. Most of the cuts are adapted for reproduction on the blackboard. The effects of alcohol and other narcotics are treated with special fulness. The subject is given a fair and judicial discussion, and those conclusions are presented which are universally accepted by the medical profession. But while this most important form of intemperance is singled out, it should be remembered that the breaking of any of nature's laws is also a form of intemperance, and that the whole study of applied physiology is to encourage a more healthy and a more noble and self-denying mode of life. CONTENTS CHAPTER PAGE I. CELLS 7 II. OF WHAT CELLS ARE MADE 10 III. DIGESTION OF FOOD IN THE MOUTH 13 IV. DIGESTION OF FOOD IN THE STOMACH 17 V. FOODS 23 VI. TOBACCO 31 VII. FERMENTATION 37 VIII. KINDS OF STRONG DRINK 42 IX. THE BLOOD 49 X. BREATHING, HEAT, AND CLOTHING 59 XI. THE SKIN AND KIDNEYS 75 XII. THE NERVES, SPINAL CORD, AND BRAIN 84 XIII. THE SENSES 100 XIV. BONES AND JOINTS 109 XV. MUSCLES 115 XVI. DISEASE GERMS 123 XVII. PREVENTING SICKNESS 132 INDEX 139 APPLIED PHYSIOLOGY CHAPTER I CELLS Our body is made of many parts. Its head thinks. Its legs carry it, and its arms and hands take hold of things. The leg cannot do the work of the arm, nor the head do the work of the hand; but each part does only its own work. =1. The simplest animal.=--Some animals have parts like a man's; but these parts are fewer. No animal has arms or hands like a man. A fish has little fins in place of legs and arms, while a worm has not even a head, but only a body, and yet it moves. An oyster has only a body and cannot move. The simplest of all animals is very small. A thousand of them would not reach an inch. Yet each is a complete animal. It is called the _ameba_. It is only a lump of jelly. It can put out any part of its body like an arm and take a lump of food. This same arm can eat the food, too. It can also put out any part of its body like a leg and move by rolling the rest of its body into the leg. It can do some things better than a man can do them, for any part of its body can do all kinds of work. So the ameba grows and moves and does as it likes. [Illustration: =Different forms of an ameba (×400).=] [Illustration: =Cells from the human body (×200).= _a_ A colored cell from the eye. _b_ A white blood cell. _c_ A connective tissue cell. _d_ A cell from the lining of the mouth. _e_ Liver cells. _f_ A muscle cell from the intestine.] =2. Cells.=--A man's finger moves and grows something like a separate animal, but it must keep with the rest of the body. A little piece of a finger moves and grows, too. If you should look at a finger, or any other part of your body, through a microscope, you would see that it is composed of little lumps of jelly. Each little lump looks like an ameba. We call each lump a cell. The cells make up the finger. =3. What cells do.=--Each cell acts much as an ameba does. From the blood it gets food and air and takes them in through any part of its body. It also grows and moves. But the cells are not free to do as they wish, for they are all tied together in armies by very fine strings. We call these strings _connective tissue_. One army of cells makes the skin, and other armies make the bones and flesh. Some armies make the fingers, and some the legs. Every part of our body is made up of armies of separate cells. =4. The mind.=--The body is a home for the mind. The cells obey the mind. The mind pays the cells by feeding them and taking good care of them. When an army of cells is hurt, the body feels sick, and then the mind tells the whole body to rest until the cells are well again. When we study about a man's body, we learn about the separate cells in his body. WHAT WE HAVE LEARNED 1. Our body is made up of many small parts. 2. The smallest parts are each like a little animal, and are called _cells_. 3. Each cell eats and grows. 4. One army of cells makes a finger and another a leg, and so on through the body. 5. The mind lives in the body. 6. The mind takes care of the cells. CHAPTER II OF WHAT CELLS ARE MADE The cells of our body are made of five common things. You would know all these things if you should see them. =5. Water.=--The first thing in the cells is _water_. Water is everywhere in the body. Even the teeth have water. Most of our flesh is water. Without water we should soon shrink up. Our flesh would be stiff like bone and no one could live. [Illustration: =The body is made of these five things.=] [Illustration: =Fat tissue (×100).= The liquid fat is stored in living pockets.] =6. Albumin.=--_Second_, next to water, something like the white of an egg makes the most of the body. The white of an egg is _albumin_. When dried it is like gelatine or glue. Albumin makes the most of the solid part of each cell. Lean meat and cheese are nearly all albumin. When it is heated it becomes harder and turns white. The word albumin means white. Dry albumin is hard and tough, but in the living cells it is dissolved in water and is soft like meat. It is the only living substance in the body, and it alone gives it strength. =7. Fat.=--_Third_, next to albumin, the most of the body is fat. Fat does not grow inside the cells of the body, but it fills little pockets between the cells. Fat does not give strength. It makes the body round and handsome. It also makes the cells warm and keeps them from getting hurt. =8. Sugar.=--_Fourth_, sugar also is found in the body. Sugar is made out of starch. When we eat starch it changes to sugar. Starch and sugar are much alike. We eat a great deal of starch and sugar, but they are soon used in warming the body. Only a little is in the body at once. =9. Minerals.=--_Fifth_, there are also some minerals in the body. When flesh is burned they are left as _ashes_. Salt, lime, iron, soda, and potash are all found in the body. [Illustration: =Starch grains (×400).= _a_, of potato. _b_, of corn.] Everything in the body is either water, albumin, fat, sugar, or minerals. These things are also our food. We eat them mixed together in bread, meat, eggs, milk, and other foods. =10. Life.=--Our food is not alive, but after we eat it the body makes it alive. We do not know how it does it. When the body dies we cannot put life into it again. There is life in each cell. WHAT WE HAVE LEARNED 1. The body is made of five things: water, albumin, fat, sugar, and minerals. 2. Water is mixed with all parts of the body. 3. Albumin makes the living part of each cell. 4. Fat is in pockets between the cells. It warms the cells and keeps them from being hurt. 5. Sugar is made from starch. It warms the body. 6. The minerals in the body are salt, lime, iron, soda, and potash. CHAPTER III DIGESTION OF FOOD IN THE MOUTH =11. Food of the cells.=--All the cells of the body work and wear out. They must eat and keep growing. The food of the cells is the blood. Water, albumin, fat, sugar, and minerals are in the blood. The cells eat these things and grow. All food must be one or more of these five things. Before they reach the blood, they must all be changed to a liquid. A few cells of the body are set aside to do this work of changing them. Changing food into blood is digestion. =12. Cooking.=--Cooking begins digestion. It softens and dissolves food. It makes food taste better. Most food is unfit for use until it is cooked. Poor cooking often makes food still worse for use. Food should always be soft and taste good after cooking. Softening food by cooking saves the mouth and stomach a great deal of work. The good taste of the food makes it pleasant for them to digest it. We must cut our food into small pieces before we eat it. If we eat only a small piece at a time we shall not eat too fast. If we cut our food fine we can find any bones and other hard things, and can keep them from getting inside the body. =13. Chewing.=--Digestion goes on in the mouth. The mouth does three things to food. _First_, it mixes and grinds it between the teeth. _Second_, it pours water over the food through fine tubes. The water of the mouth is called the saliva. The saliva makes the food a thin paste. _Third_, the saliva changes some of the starch to sugar. Starch must be all changed to sugar before it can feed the cells. =14. Too fast eating.=--Some boys fill their mouths with food. Then they cannot chew their food and cannot mix saliva with it. They swallow their food whole, and then their stomachs have to grind it. The saliva cannot mix with the food and so it is too dry in the stomach. Then their stomachs ache, and they are sick. Eating too fast and too much makes children sick oftener than anything else. Birds swallow their food whole, for they have no teeth. Instead, a strong gizzard inside grinds the food. We have no gizzards, and so we must grind our food with our teeth. =15. Teeth.=--We have two kinds of teeth. The front teeth are sharp and cut the food; the back teeth are flat and rough and grind it. If you bite nuts or other hard things you may break off a little piece of a tooth. Then the tooth may decay and ache. After you eat, some food will sometimes stick to the teeth. Then it may decay and make your breath smell bad. After each meal always pick the teeth with a wooden toothpick. Your teeth will also get dirty and become stained unless you clean them. Always brush your teeth with water every morning. This will also keep them from decaying. [Illustration: =Digestive organs of a bird.= _a_ esophagus or swallowing tube. _b_ crop or bag for carrying food. _c_ stomach. _d_ intestine. _e_ gizzard or food grinder.] =16. Swallowing.=--When food has been chewed and mixed with saliva until it is a paste, it is ready to be swallowed. The tongue pushes the food into a bag just back of the mouth. We call the bag the _pharynx_. Then the pharynx squeezes it down a long tube and into the stomach. The nose and windpipe also open into this bag, but both are closed by little doors while we swallow. We cannot breathe while we swallow. If the doors are not shut tightly, some food gets into the windpipe and chokes us. WHAT WE HAVE LEARNED 1. We eat to feed the cells of the body. 2. All food must be made into blood. 3. Changing food to blood is digestion. 4. Cooking softens food and makes it taste good. 5. Food is ground fine in the mouth, and mixed with saliva to form a paste. Some of its starch is changed to sugar. 6. If food is only half chewed the stomach has to grind it. 7. When we swallow, the tongue pushes the food into a bag back of the mouth and the bag squeezes it down a long tube to the stomach. CHAPTER IV DIGESTION IN THE STOMACH =17. The stomach.=--When food is swallowed it goes to the stomach. The stomach is a thin bag. In a man it holds about three pints. Like the mouth, it does three things to the food. [Illustration: =Gastric glands in the stomach (×200).= The cells _a_ and _b_, form the juice. The fibers _c_, bind the tubes in place.] _First_, the stomach gently stirs and mixes the food. _Second_, it pours a fluid over the food. This fluid is called the _gastric juice_. The gastric juice is sour and bitter. _Third_, the gastric juice changes some of the albumin of food to a liquid form. If the mouth has done its work well, the stomach does its work easily and we do not know it. But if the mouth has eaten food too fast and has not chewed it well, then the stomach must do the work of the mouth too. In that case it gets tired and aches. =18. The intestine.=--The food stays in the stomach only a little while. All the time a little keeps trickling into a long coil of tube. This tube is called the _intestine_ or the _bowels_. Three or four hours after a hearty meal the stomach is empty. Some of the food has been changed to a liquid, but most of it has only been ground to smaller pieces, and mixed with a great deal of water. Now it all must be changed to a liquid. =19. What the intestine does.=--Like the mouth and stomach, the intestine does three things. _First_, it mixes the food and makes it pass down the tube. _Second_, two sets of cells behind the stomach make two liquids and pour them into the intestine. One set of cells is the _sweetbread_, or _pancreas_, and its liquid is the _pancreatic juice_. The other is the _liver_ and its fluid is the _bile_. _Third_, the pancreatic juice makes three changes in food. _First_, like the mouth, it changes starch to sugar. _Second_, like the stomach, it makes albumin a liquid. _Third_, it divides fat into fine drops. These drops then mix with water and do not float on its top. =20. Bile.=--The bile is yellow and bitter. It helps the pancreatic juice do its work. It also helps to keep the inside of the intestine clean. =21. Digestion of water and minerals.=--Water and the mineral parts of food do not need to be changed at all, but can become part of the blood just as they are. Seeds and husks and tough strings of flesh all pass the length of the intestine and are not changed. =22. How food gets into the blood.=--By the time food is half way down the intestine it is mostly liquid and ready to become part of the blood. This liquid soaks through the sides of the intestine and into the blood tubes. At last the food reaches the end of the intestine. Most of its liquid has then soaked into the blood tubes and only some solid waste is left. =23. Work of the liver.=--The food is now in the blood, but has not become a part of it. It is carried to the liver. There the liver changes the food to good blood, and then the blood hurries on and feeds the cells of the body. Spoiled food may be swallowed and taken into the blood with the good food. The liver takes out the poisons and sends them back again with the bile. The liver keeps us from getting poisoned. =24. Bad food.=--Sometimes the stomach and intestine cannot digest the food. They cannot digest green apples, but they try hard to do so. They stir the apples faster and faster until there is a great pain. Sometimes the stomach throws up the food and then the pain and sickness stop. Spoiled food makes us sick in the same way. =25. Too fast eating.=--When the food stays too long in the stomach or intestine it sours, or decays, just as it does outside of the body. This makes us very sick. When we eat too much, or when we do not chew the food to small pieces, the stomach may be a long time in digesting the food. Then it may become sour and make us sick. =26. Biliousness.=--When the food is poor or becomes sour, it is poorly digested. Then the liver has more work to do, and does not change the food to blood as it should. It also lets some of the sour poisons pass by it. These poison the whole body and make the head ache. We call this _biliousness_. The tongue is then covered with a white or yellow coat and the mouth tastes bad. These are signs of sickness. The stomach and liver are out of order. =27. Rules for eating.=--If we eat as we should, our stomach will digest its food. We must follow three rules. _First_, we must chew the food in the mouth until all the lumps are fine. Then the food will be ready for the stomach. _Second_, we must eat slowly. If we eat fast we cannot chew the food well. The stomach cannot take care of food if it comes too fast. We must swallow all of one mouthful before we put another into the mouth. _Third_, we must eat only at meal times. The stomach needs a rest. Even a little candy, or apples, or nuts will keep the stomach at work, and tire it out. A child needs to eat more often than his father. So, besides his meals, he should have something to eat in the middle of the morning and some more in the afternoon. But he should not be eating at all hours. He ought not to eat little bits just before dinner, for that spoils his meal. WHAT WE HAVE LEARNED 1. The stomach and intestine stir and rub the food, and mix it with juices. 2. The juices change albumin to a liquid, and starch to sugar. They also change fat to the form of tiny drops. 3. The digested food soaks through the sides of the intestine into the blood tubes. 4. The blood carries the food to the liver. 5. The liver changes food to blood. 6. Blood goes to all parts of the body and feeds the cells. 7. The liver keeps poisons from getting into the blood. 8. Water and minerals become a part of the blood without being digested. 9. When food is not well digested, the liver cannot make it into good blood. This makes us bilious. 10. If food is not soon digested it sours and decays. This makes us sick. 11. We can make food digest quickly by chewing it well and eating slowly. CHAPTER V FOODS =28. Kinds of food.=--The cells of the body need water, albumin, fat, sugar, and minerals for food. We sometimes eat sugar alone, and we drink pure water. But most of our food is a mixture of all five kinds of food. Food comes from animals and plants. =29. Milk=.--Milk is the best food known. It contains just enough water, albumin, fat, sugar, and minerals. Babies and young mammals live on milk alone. A man can live upon four quarts of milk a day. In sickness, milk is the very best food for men, as well as for babies. The albumin of milk becomes hard when the milk sours. This makes _cheese_. The fat of milk rises to the top. We call it _cream_. When cream is churned, the pure fat comes together in a lump. Pure fat of milk is called _butter_. Cheese and butter are both good foods. =30. Eggs.=--Eggs are also good food. The white of an egg is almost pure albumin. The yolk is albumin and fat. Eggs have no starch or sugar. They are not a perfect food, for some sugar must be eaten. But they can be quickly digested and they produce a great deal of strength. =31. Meat.=--Meat contains albumin and fat, but no sugar. Fish, oysters, and clams are like meat. They all make good food. Boys and girls should eat milk, eggs, and meat. These foods are the best to give strength to the body. Nearly all food from animals is more quickly digested and gives more strength than food from plants. =32. Bread.=--White bread is a food made from wheat. The wheat is ground to flour. Flour is mixed with water, and yeast is added. The yeast makes a gas, and the gas puffs up the wet flour and makes it full of holes. The holes make the bread _light_. Then bread is baked. Rye or corn meal makes good bread. Cake, biscuit, and pancakes are much like bread. Sometimes in place of yeast, baking powder is used to make the bread or cake light. =33. Meal.=--Oatmeal, corn meal, and cracked wheat and rice are sometimes boiled, and eaten with milk. Bread, biscuit, oatmeal, and corn meal are made from grain. All are very much alike. The cooking makes them look and taste different, but yet they are nearly the same. =34. Why we need grain food.=--All kinds of grain have much albumin, but only a little fat. But all have a great deal of starch. By digestion the starch becomes sugar. Grain is a good food because it has starch or sugar. Animal foods have no sugar, so we eat grain food with them. The two together make the most nourishing food. Potatoes have a great deal of starch and only a little albumin. They also are good food with meat. [Illustration: =A healthy man needs as much food as this every day.=] A person cannot live well upon plant food alone, for it has too much starch and sugar, and too little albumin and fat. We need nearly equal parts of albumin, fat, and sugar. A mixture of bread, meat, eggs, vegetables, and milk makes the best food. =35. Fruit.=--Fruit, like apples, peaches, and plums all have sugar. They taste good, and give us an appetite for other kinds of food. They have little albumin or fat. =36. Salt.=--There is enough mineral matter in all food, and we do not have to eat iron or lime or soda. But we do need some more salt. Even animals need salt. Salt makes food taste good, and helps its digestion. [Illustration: =People are made sick by drinking water from such a well.=] =37. Water.=--Water is also a food, for it forms the most of our bodies. All food has water. Even dry crackers contain it. =38. Pure water.=--Water in a well runs through the dirty earth, and yet is clear and pure. This is because sand holds back the dirt. But sometimes slops from the house, and water from the barn yard, soak through the soil until the sand is full. Then the well water will be dirty and poisonous. People are often made sick by drinking such water. In cities the dirt fills all the soil and spoils the water. So the water must be brought from the country in large pipes. Water in lead pipes takes up some of the lead. Lead is a poison. You should let the water run off from a pipe a little while before you use it. Good water is clear and has no smell or taste. Dirty or yellow water, or water with a taste or smell, is not fit for use. =39. Tea and coffee.=--Tea and coffee are steeped in water and used as a drink. The drink is the water. The tea and coffee are neither food nor drink. They cause the cells of the body to do more work, and at the same time they take away the feeling of being tired. They do not give strength to the body, but are like a whip and make the body work harder. =40. The appetite.=--When we have so many kinds of food, what kind is best for us? The taste of food tells us the kind of food to eat. Bread and meat, and such plain foods, always taste good, and we never get tired of them. Sugar tastes good until we get enough. Any more makes us sick. More than enough sugar or starch is found in bread and potatoes. [Illustration: =One kind of intemperance.=] If we can eat food day after day, without getting tired of it, the food is good for us. If we get tired of its taste, either the food is not good for us or we are eating too much. Bad tasting or bad smelling food is always dangerous. We can tell how much food to eat by our _hunger_ or _appetite_. We can always feel when we have enough. Then is the time to stop. Sometimes we eat plain bread and meat until we have enough, and then sweet cake or pie is brought in. Then we have a false appetite for sweet things. If the sweet things had not made a false hunger, we should have had enough to eat. But the false appetite makes us want more, and so we eat too much, and sometimes get sick from it. =41. Intemperance.=--Eating for the sake of a false appetite is _intemperance_. Drinking strong drink for the sake of its taste is a common form of intemperance. But eating too much preserves, pie, and candy is intemperance too, and can do a great deal of harm. A little pie, or pudding, or candy, is good, because we can eat our sugar as well that way as in bread. But we should eat only a little. =42. Food and Diseases.=--If our food is dirty or is handled with dirty hands, or is put into dirty dishes, there may be disease germs in it. Our food should always be clean, and we should have our hands clean when we handle it or eat it. Storekeepers sometimes keep fruit and vegetables out of doors where street dust may blow upon it. This dust is often full of disease germs. Flies may also bring disease germs to the food. If food is kept where dust and flies can get at it, we ought not to buy it. WHAT WE HAVE LEARNED 1. Food is a mixture of water, albumin, fat, starch or sugar, and minerals. 2. Animal foods, like milk, eggs, and meat, have albumin and fat in the best form. 3. Plant food has albumin and fat, but it has very much starch or sugar. So, taken together with animal food, it makes a complete food. 4. Lime, iron, soda, and salt are found in all foods, but we must add a little more salt to food. 5. Water is found in all food, but we must drink some besides. 6. Dirty water, or water with a taste or smell, is not fit for use. 7. Taste tells us what kind of food to use. 8. Hunger, or the appetite, tells us how much food to use. 9. There can be a false hunger for sweet things. This may lead us to eat too much. 10. Eating too much of sweet things is one form of intemperance. CHAPTER VI TOBACCO =43. Harmful eating.=--Men often eat for the fun of eating, and sometimes they eat harmful things. They chew tobacco and drink strong drinks, because they like their taste, just as a child eats candy. =44. Tobacco.=--Men have always drunk strong drink. Within the last four hundred years, men have learned another way to please a wrong taste. When Columbus discovered America, the Indians were using tobacco. They taught the Spaniards how to smoke it, and since then almost the whole world has used it. Tobacco is the leaf of a tall plant. It needs a better soil than any other crop. It takes the richness from the ground, and spoils it for other crops. =45. Nicotine.=--About 1/30 of each tobacco leaf is a strong poison. This poison is called _nicotine_. A drop or two of it, or as much of it as is in a strong cigar, will kill a man. It gives the tobacco its smell and taste. Men use tobacco for the sake of a poison. =46. Why men use tobacco.=--Men give queer reasons for using tobacco. One smokes for its company, another because he is with company. One smokes to make his brain think better, and another to keep himself from thinking. Some use tobacco to help digest their food, and others use it to keep themselves from eating so much. Boys smoke to make themselves look like men. The real reason for using tobacco is that men learn to like its taste, and do not care if it harms them. =47. Spitting.=--Tobacco in any form makes the saliva flow. Men do not dare swallow it, for it makes them sick. So they spit it out. No one likes to see this. It is a dirty and filthy habit. Besides, the saliva is lost, and cannot help digest food. Tobacco stains the teeth brown. You can always tell a tobacco chewer by his teeth. His breath will smell of tobacco, and even his clothes are offensive to the nose. =48. Tobacco lessens strength.=--Tobacco always makes a person sick at the stomach, at first. After a while, he becomes used to it, and an ordinary chew or smoke does not make him sick. But a large chew or smoke will always make him sick again. When a person is sick from tobacco he is very weak. Even if he is not sick, the tobacco poisons his muscles and makes his strength less. When a man trains for a hard race he never uses tobacco. =49. Tobacco hinders digestion.=--Tobacco and its smoke both have a burning taste. This makes the throat sore, and causes a cough. Tobacco does not help the stomach to digest food. Smokers and chewers often have headaches and coated tongues. These are signs of a poor digestion. =50. Effect upon the young.=--Tobacco is more harmful to boys than to men. If boys smoke they cannot run fast or long. They cannot work hard with their brains or hands. They do not grow fast, and are liable to have weak hearts. =51. Tobacco harms others.=--Many persons do not like the smell of tobacco, and no one likes the spit. No one should use it in the presence of others. The tobacco user's pleasure should not spoil the comfort and happiness of others. =52. Snuff.=--Powdered tobacco is called snuff. Snuff causes sneezing. No one should harm the nose and the whole body for the pleasure of a sneeze. Years ago snuff was used much more than it is now. =53. Chewing.=--Chewing tobacco is the most poisonous way of using it, for it keeps most of the nicotine in the mouth. Chewing will make any one very sick, unless he spits out all the saliva. =54. Smoking.=--Men smoke pipes, cigars, and cigarettes. The smoke has nicotine, and is poisonous. Pipe stems get dirty and full of nicotine. After a while they smell bad and are very poisonous. An old smoker's pipe will make a young smoker sick. =55. Cigarettes.=--Cigars are not so poisonous as a pipe, for more of the nicotine is burned up. Cigarettes are often made of weak tobacco. A cigarette does not contain so much tobacco as a cigar. Hence a cigarette does not cost much. It can be smoked in a hurry. It does not make a boy so sick as cigars do. Boys and men use a great many cigarettes where they would not touch a cigar. This makes the use of cigarettes the most dangerous form of smoking. Selling cigarettes to young boys is forbidden by law. =56. Habit.=--When men have used tobacco for some time, they like it and feel bad without it. So they get into the habit of using it, and find it hard to stop. The tobacco seems to help them, but it does not do so. It cheats men, and they do not know it. =57. Chewing gum.=--Chewing gum is made from pitch or paraffin, for these substances will not dissolve in the mouth. The gum is flavored with sugar and spices. The gum and its flavors are not harmful in themselves, and yet chewing them is harmful. Chewing makes a great deal of saliva flow. All this saliva is wasted, and when we eat our meals we may have too little. Then our food will not digest well, but we shall have dyspepsia and headaches. By pulling and handling the gum while chewing it, you may get some poisonous dirt into your mouth, and make yourself very sick. Even if your gum should not harm you, there is a good reason for letting it alone. When you are chewing gum, you look as if you were chewing tobacco. No one likes to see a boy or girl even appearing to chew tobacco. If you form a habit of chewing gum you will be more likely to chew tobacco when you are grown. WHAT WE HAVE LEARNED 1. Men use tobacco for the sake of its nicotine. Nicotine is a very strong poison. 2. Tobacco causes a man to waste his saliva. 3. Tobacco makes the mouth dry. 4. Tobacco hinders digestion. 5. Tobacco stains the teeth, and makes the breath smell bad. 6. Tobacco makes a person sick at the stomach. 7. Tobacco weakens the muscles. 8. Tobacco is more harmful to the young than to grown persons. 9. Chewing is the worst form of using tobacco. 10. Smoking cigarettes is the worst form of smoking. CHAPTER VII FERMENTATION =58. Souring of fruit.=--When a little fruit is set away in a warm place for a day or two it sours or ferments. Anything sweet will do the same thing. Little bubbles rise up through the juice and a foam comes on top. Then the juice has a sharp taste or is sour. Canned and preserved fruit becomes sour soon after the jar is opened, and cider soon turns to vinegar. All fruit juice does this even in cold weather. But in cold weather it keeps for a longer time. [Illustration: =Fermentation in a jar of cherries.=] =59. Preserving fruit.=--If your mother wishes to keep fruit all winter she boils it and at once puts it into tight jars. This shuts out the air and then the fruit keeps good all winter. Boiling kills all living things, and no more can get in through the tight jars. Does a living thing have anything to do with making the fruit juice turn sour? =60. Yeast.=--Yeast will make all sweet things ferment. Bakers make yeast grow in bread sponge. Yeast is alive. It is made of millions of tiny round cells. New cells sprout out from the side of the old cells like young lilies on an old lily bulb. Soon each new cell breaks off and lives all by itself. In a single night enough new cells will form to fill the whole loaf of bread. [Illustration: =Yeast plant cells (×500).=] =61. How yeast makes alcohol.=--Yeast will grow only where sugar is. When it has grown for some time there is no more sugar, and instead of a sweet taste there is a sharp or sour taste. The yeast has changed the sugar to alcohol. All alcohol is made from sugar by yeast. The seeds of the yeast plant are everywhere in the air. Some are on the skins of fruit and so are found in the juice when it is squeezed out. There they begin to grow at once and soon change the sugar to alcohol. They do this by taking a gas away from the sugar. The gas rises in little bubbles, and makes a froth upon the top of the juice. Boiling kills the yeast plant. If the juice is at once put into tight jars no new yeast plants can get in, and so the juice keeps. =62. Vinegar.=--Sometimes fruit juice turns sour. The sourness is due to vinegar. Besides yeast, other little living plants fall into the juice and turn the sugar to vinegar. But if there is much alcohol in the juice, the vinegar plants will not grow. =63. Yeast in bread.=--Growing yeast plants always make alcohol. They change some of the sugar of bread dough to alcohol and a gas. The gas bubbles through the bread and makes it light. When bread is baked, the heat of the oven drives off the alcohol, and so we do not eat any in bread. =64. Alcohol.=--Alcohol is a clear liquid and looks like water. It has a sharp taste and smell. It burns very easily and makes a very hot flame. Its smoke cannot be seen, and its flame will not make anything black, as a match flame will do. =65. Use of alcohol.=--Alcohol will dissolve more things than water will dissolve. It is used to dissolve drugs, varnishes, perfumery, and many other things. It will dissolve even oil and fat. Tailors clean grease spots from clothes with it. It takes water away from flesh and makes it dry, hard, and tough. It will keep anything from rotting. In museums we pour alcohol over pieces of flesh or plants in glass jars. Then they will keep and we can look at them at any time. Thus alcohol is a very useful thing, and we could hardly do without it. =66. Strong drink.=--Some men use alcohol in a wrong way. They swallow it as a drink. But men cannot drink pure alcohol, for it would burn their mouths. They always drink it mixed with some water. Alcohol in water is called _strong drink_. =67. Why men use strong drink.=--Some men take strong drink to make themselves warm, and some to make themselves cool. Some drink to keep themselves awake, and some to make themselves sleep. Some drink to keep themselves still, and some to make themselves stir around faster. Men use strong drink really because it seems to make them feel strong for a while. It does not make them stronger, but it harms the body and the mind. Its alcohol does the harm. WHAT WE HAVE LEARNED 1. Sugar in fruit or in water turns to alcohol or vinegar, and a gas. 2. The change to alcohol is caused by the cells of the yeast plant. 3. The change to vinegar is caused by another small plant. 4. Boiling fruit juice kills the yeast plants and then the juice will keep without change. 5. Alcohol looks like water. It has a sharp and burning taste. 6. Alcohol takes water from flesh and hardens it. 7. Alcohol burns with a great heat and no smoke. 8. Alcohol is used to dissolve things, and to keep things from spoiling. 9. Alcohol in water forms _strong drink_. CHAPTER VIII KINDS OF STRONG DRINK =68. Wine.=--All strong drink is alcohol and water. There may be other things to give it taste, but alcohol and water are always in it. No strong drink is over one half alcohol. [Illustration: =A glass of wine contains so much alcohol.=] In olden times wine was the only strong drink. Men used to crush out the juice of grapes and let it ferment. This made wine. But very often they used the juice before it fermented. Then it had no alcohol and could do no harm, but was a good food. We read of wine in the Bible. Some of it was fresh fruit juice. In wine, the sugar is changed to alcohol. The rest of the juice stays the same. All wine is made by the yeast plant growing in fruit juice. No yeast is put in, for there is always enough on the outside of the fruit. Wine is about one tenth alcohol. =69. Homemade wine.=--Cider is a kind of wine. It is made from apple juice. It has alcohol a day or two after it is made. All homemade wines have alcohol. Any of them can make a person drunk. Using weak homemade wine and cider often makes an appetite for stronger drinks. The alcohol in any of them is enough to harm the body. [Illustration: =A glass of beer contains so much alcohol.=] =70. Beer.=--After man had made wine for a long time, some one found out how to cultivate yeast. Then men could make sugar and water ferment whenever they wanted to. So men boiled grain to take out its sugar. Then they poured off the liquor and added yeast and let it ferment. This made beer and ale. Now millions of bushels of grain are used every year in making beer. Men call beer a _light_ drink. But it has alcohol and is a strong drink, and can make men drunk. =71. Root beer.=--Some persons boil roots and herbs, and add molasses and yeast. Then the liquid ferments and becomes _root beer_. They say "it has no alcohol, for we made it." But it does have alcohol, for yeast always makes alcohol. Some ginger ale is made by putting yeast in sweetened ginger water. It has alcohol, too. =72. Distillation.=--Boiling water turns to vapor or steam and goes off in the air. When the vapor is cooled, you can see the water again. It often cools on the window and makes little streams of water. You can catch the steam in a tube. If you keep the tube cool, the steam will turn to water in the tube. This process is called _distillation_. [Illustration: =A glass of whisky contains so much alcohol.=] Boiling alcohol also passes off into the air as vapor. When the vapor is cooled, it becomes liquid again. Alcohol boils with less heat than water. When alcohol in water is heated, the alcohol boils first. So the vapor has more alcohol than the water. When the vapor is cooled, the liquid has more alcohol than it had at first. When the liquid is distilled again it has more alcohol yet. Pure alcohol can be made in this way. =73. Whisky.=--Distilling wine or strong beer makes _whisky_ and _brandy_. Whisky is one half alcohol. It is more harmful than wine or beer. =74. Habit.=--Some strong drinks have only a little alcohol and some have a great deal. No one begins to drink the strong liquors. He begins with wine or beer. When he has once learned, he has a hard time to stop drinking. It is dangerous to drink even weak drinks. =75. Strong drink and thirst.=--When a man is thirsty, water will satisfy him but strong drink will not. Sometimes the mouth is dry and dirty and then a man feels thirsty. Rinsing the mouth with water, and rubbing the tongue and teeth clean will help the dryness and stop the thirst. At any rate, strong drink will only make the mouth dryer. Some men drink only when they are tired. Then a cup of strong and hot tea or coffee will make them feel much better than a glass of strong drink, and will not harm them so much. When strong drink is swallowed, its alcohol takes water from the mouth. When your mouth is dry, you feel thirsty. Strong drink makes the mouth dry, and so a drink makes a man more thirsty. The alcohol also makes the mouth smart. Men need another drink to cool the mouth after the first one. So one drink leads to another. All the while a person drinks water with the alcohol until he has too much water. But his mouth is dry and he feels as thirsty as ever. =76. Effect of alcohol upon the stomach.=--When strong drink is swallowed it makes the stomach smart just as it does the mouth. So the stomach feels warm, but it is really no warmer. This harms the stomach and keeps it from working well. Alcohol also keeps the gastric juice from changing albumin to a liquid. Alcohol keeps flesh from decaying in a museum. In the same way it may hinder the digestion of food in the stomach. When alcohol is used for only a short time, the stomach can get well; but if it is used for months and years, the stomach will stay weak. Then the drinker can hardly eat at all. =77. What becomes of alcohol.=--In the stomach a great deal of gastric juice is mixed with the alcohol. So it is very weak when it reaches the intestine. Alcohol needs only a little digesting. It soon soaks into the blood from the intestine along with the other food. The blood flows fast and washes the alcohol away as soon as it leaves the intestine. Too little gets into the blood at once to harm it much. Alcohol goes to the liver, and is there destroyed; but it still does great harm. The liver has to attend to the alcohol, and so it does not change the food to good blood, and it does not take all the poisons out of the blood. Then the whole body becomes weak and sick. Alcohol hurts the liver first, and more than other parts of the body. On this account, drinkers often have bilious attacks and stomach troubles. =78. Bitters.=--Many medicines are made by dissolving drugs in alcohol. In taking a strong medicine, we use only a few drops, and so do not get much alcohol. Some kinds of medicines must be taken in large doses. Bitters are weak medicines, and must be taken by the tablespoonful. A tablespoonful of the medicine has more alcohol than a large drink of whisky. The bitters seem to make a person feel well, but it is because he is taking a large amount of strong drink. Jamaica Ginger is only common ginger dissolved in alcohol. It, too, is a form of strong drink. =79. Strong drink as medicine.=--People sometimes keep whisky or brandy in the house to give for colds or other slight forms of sickness. A drink of hot coffee does more good than the strong drink, and has none of its dangers. By using whisky or brandy for medicine, children learn to believe in strong drink, and so they will be likely to use it when they grow up. This reason alone ought to keep any one from giving it to a child. =80. Alcohol in cooking.=--In making bread, alcohol is formed in the dough by the yeast. When the bread is baked, all the alcohol is driven off by the heat, and so we do not eat any. Sometimes brandy or wine is put into desserts. If it is put in after the dessert is cooked, we shall get as much alcohol as if we had drunk it. If the liquor is put in before cooking, the heat will drive off the alcohol but the flavor of the liquor will remain. The flavor will do no harm in itself, but people will learn its taste, and from it may learn to like the strong drink itself. The alcohol in bread has no special flavor and does not leave any taste behind. So we cannot learn to like strong drink by eating bread. WHAT WE HAVE LEARNED 1. Fruit juice makes wine or cider. 2. All kinds of wine contain alcohol. 3. When the liquid from boiled grain has fermented, it becomes beer, or ale. 4. By boiling wine or beer, and cooling the vapor, distilled drinks like whisky are made. They are one half alcohol. 5. Water will satisfy a real thirst. Strong drink will not. 6. Alcohol keeps the stomach from digesting food. 7. Alcohol soaks into the blood tubes and goes to the liver. 8. The liver destroys the alcohol, but is hurt in doing it. CHAPTER IX THE BLOOD =81. Blood.=--After food becomes blood, it goes to every part of the body to feed the cells. Even a pin prick anywhere in the body draws blood. The blood makes the skin pink. There are five or six quarts of blood in a man's body. This is about 1/13 of his body. [Illustration: =Blood corpuscles (×400).= _a_ a pile of red blood cells. _b_ red blood cells seen flatwise. _c_ red blood cells seen edgewise. _d_ white blood cells.] Blood looks like a red liquid. But if you look at it through a strong microscope, it looks like water, and millions of little red cells. These cells carry air through the body. They make the blood look red. There are also a smaller number of white cells. Blood is made of red cells, white cells, and a liquid. =82. The liquid in blood.=--The liquid part of the blood is albumin, and water, with a little fat, sugar, and minerals. It is food and drink for the cells of the body. When blood is drawn from the body it soon becomes like jelly. We call the jelly a _clot_. When you cut your finger, a clot forms in the cut and plugs up the bleeding place. If it did not, the blood would all run out of the body and we should die. [Illustration: =Diagram of the heart while it is beating.= _a_ vein entering the auricle. _b_ auricle. _c_ closed valve to keep blood from flowing back into the auricle. _d_ ventricle. _e_ artery. _f_ valve to keep blood from returning to the ventricle.] =83. The heart.=--The blood is held in tubes. A pump inside the body keeps it always moving. This pump is called the _heart_. The heart is a bag of muscle with thick sides. It is about as large as your fist. When it is full, it has the power to make itself smaller, and so it squeezes the blood out through a tube. We can feel each squeeze as a heart-beat. You can find the heart-beat just to the left of the middle of the body about two hand-breadths below the neck. =84. The heart-beat.=--A man's heart beats about seventy times each minute. Boys' and girls' hearts beat much faster. Running or hard work of any kind makes the heart beat faster yet. Your heart will keep on beating until you die. It does not seem to rest at all, yet it works only while you feel it beat. Between each beat it rests while the blood is filling it again. So it really rests one half of the time. =85. Arteries.=--The heart pumps the blood through a single tube. This tube opens into smaller tubes. These open into still smaller ones. You must use a strong microscope to see the finest blood tubes. The tubes reach every part of the body, and carry blood to its cells. They are called _arteries_. At each heart-beat a wave of blood can be felt in an artery. This wave is the _pulse_. It can be felt in the wrist, temples, and other places. By the pulse we can tell how often and how strongly the heart is beating. [Illustration: =Arrangement of capillaries.= _a_ smallest artery. _b_ smallest vein. _c_ network of capillaries.] =86. Capillaries.=--The smallest arteries divide into a fine network of small tubes. These tubes are the _capillaries_. They lie around every cell of the body. Their sides are very thin. As the blood flows through them, some of it soaks through the sides of the tubes. Blood contains all kinds of food for the cells. Each cell is always wet with food and can eat it at any time. The cells are like the tiny animal, the ameba, and can take in the food by any part of their bodies. The cells are better off than the ameba, for their food is brought to them. They pay the body for their food by working for it. =87. Veins.=--The capillaries come together again to form large tubes. These tubes are called _veins_. Only a little of the blood goes through the sides of a capillary. The rest flows on into the veins. The veins unite to form two large tubes. These two tubes open into the heart. =88. How the blood flows.=--The blood is pumped out of the heart, through the arteries to the capillaries. There some goes out to the cells. The rest flows into the veins and goes back to the heart. All the blood in the body passes through the heart every two minutes. It takes only twenty seconds for a drop of blood to go from the heart to the toes and back again. The arteries are deep in the flesh, but some of the large veins can be seen upon the back of the hands. =89. Bleeding.=--If a large artery or vein is cut there is a great deal of bleeding. You can always stop a cut from bleeding by holding it fast between the hands. Do not be afraid of the blood when you see any one bleeding, but hold the sides of the cut tightly with both of your hands. This will stop any bleeding until help comes. You may keep a person from bleeding to death by doing this when other persons are afraid of the blood. =90. Healing cuts.=--When your flesh is cut it soon grows together again. The work of the little white cells in the blood is to help heal cuts and wounds and bruises. These cells are like little amebas in the blood. They keep moving around with the blood, and now and then burrow outside the capillaries to see if all is well. If they find a cut, hundreds and thousands rush to the spot at once. Some eat up any specks of dirt on the cut. Others fit themselves into the sides of the cut and grow long and slender, like strings, and so bind the two edges of the cut together. In this way all cuts are healed. [Illustration: =Bacteria growing in a kidney and producing an abscess (×300).= _a_ kidney tube. _b_ white blood cell attacking bacteria. _c_ bacteria. _d_ blood vessel of the kidney.] =91. The white blood cells kill disease germs.=--There are tiny living beings everywhere in the air, and soil, and water. Some of them can grow inside a man and make him sick. These tiny things are called _disease germs_. One kind gives a man typhoid fever, and another diphtheria. Another kind grows on cuts, and sometimes makes them very sore. The white cells of the blood are always watching for these enemies, like a cat hunting mice, and when they find them they at once try to kill them. But sometimes the white blood cells get killed. Then they look like cream in the cut. We call this creamy liquid _matter_ or _pus_, and say "We have caught cold in the cut." In most pricks and cuts the white cells of the blood can kill all these enemies and also heal the cut. =92. Catching cold.=--Sometimes the cold air blows on our head and hurts the cells of the nose. If there are disease germs in the air, they may grow in the injured part of the nose and make us have a "cold in the head." Then the white blood cells gather at the spot so as to kill the disease germs. Also the arteries bring a great deal of blood to the nose so as to heal the injured parts. Some of the white blood cells and the liquid from the blood run out, and we have to blow the nose. The white blood cells help to make us well whenever we catch a cold or other kind of sickness. =93. Red blood cells.=--The red blood cells are like tiny flat plates. They float in the liquid part of the blood and make the blood look red. They carry air from the lungs to the cells of every part of the body, and thus help all the cells to breathe. =94. Why the heart beats hard when we run.=--When we work hard, the cells of our bodies need a great deal of food. So the heart beats much harder, and sends them much more blood. We can feel our heart beat when we run hard. When the cells work they get more blood in another way. The arteries become larger and hold more blood. Then the part looks red and feels warm. Thus your face gets red when you run hard. This is because your heart and arteries bring more blood to feed the working cells. =95. Need of a strong heart.=--The heart must keep sending blood to feed the cells. If it should stop for only a little while, the cells would starve to death and we should die. We need strong hearts. When we work very hard for a long time, the heart gets tired. Then the cells do not get enough food and we feel weak all over. Boys ought not to run and lift till they are tired out, for this hurts their hearts. =96. What alcohol does to the blood.=--Alcohol hinders the digestion of food. Then too little food will reach the blood, and so the cells of the body will get too little. Alcohol does not add strength to the body, but it takes it away. It seems to make men stronger, for it takes away their tired feelings. But it makes them really weaker, for it harms the blood. =97. How alcohol affects the heart.=--Alcohol at first makes the heart beat more strongly and quickly, but it tires it out and makes it weaker. Then the heart pumps too little blood to the rest of the body, and a man is weaker all over. If a drinker tries to run or work hard, his heart may not pump enough food to the working cells of his arms and legs. Strong drink takes away a man's strength and makes him less able to endure a long strain. =98. How alcohol harms the arteries.=--Alcohol causes the arteries to become larger and to carry more blood. Then the face will be red and the skin will become warm. This makes a person feel well, and he seems to be helped. His blood seems to be flowing faster because his face is red. But really it is flowing slower. When the arteries have been made large very often, they stay large all the time. A drinker's nose is often red from this cause. Alcohol sometimes causes the arteries to become hard, and even to change to a kind of bone. Then they cannot change their size to carry just so much blood as each part needs. =99. How tobacco affects the heart.=--Tobacco weakens all the body, but it harms the heart more than the rest. It often makes the heart beat slowly at one time and fast at another. It weakens the heart and keeps it from working harder when the working cells need more food. A smoker gets out of breath quickly. He cannot run far or work very hard. Chewing is a still more harmful form of using tobacco. When men train for a game or a race they never use tobacco. Boys are not so strong as men, and so tobacco is more hurtful to them. Boys are harmed by tobacco far more than men. Cigarette smoke harms their stomachs and keeps food from their blood. If boys smoke, they become pale and weak. The poisonous smoke weakens the heart, and they cannot run or work so hard as they should. Even if a father uses tobacco, he should not allow his boys to use it. WHAT WE HAVE LEARNED 1. Blood is a liquid. It contains many round red cells and a few white cells. 2. Blood contains all kinds of food for the cells of the body. 3. The blood is kept moving by the heart. 4. The heart pumps or beats about seventy times a minute. 5. The blood flows through arteries to all parts of the body. 6. The arteries open into the capillaries. Capillaries make a network around each cell of the body. 7. Some of the liquid parts of the blood go out through the sides of the capillaries and become food for the cells of the body. 8. From the capillaries the blood flows into the veins and back to the heart. 9. Bleeding can be stopped by holding the cut tightly between the hands. 10. The white blood cells grow into the sides of cuts, and so heal them. They also guard the body against the seeds of many diseases. 11. The red blood cells carry air to the cells of the body. 12. Alcohol weakens the heart and arteries. 13. Tobacco harms the heart. CHAPTER X BREATHING, HEAT, AND CLOTHING =100. The lungs.=--Our food becomes blood and feeds the cells of our body, but we grow only a little heavier. What becomes of the food? [Illustration: =The air tubes and lung.= _a_ larynx or voice box. _b_ trachea or windpipe. _d_ air sacs, each like a tiny frog's lung.] Besides food, air is always getting into our bodies. In breathing, air passes through the nose into a tube in the neck. This tube is called the _windpipe_. You can feel it as a pile of hard rings in the front part of the neck. The windpipe divides into many branches. At the end of its smallest branches are little bags or sacs. The branches and the sacs make the two lungs. So a lung is a soft and spongy piece of flesh, and can be blown up like a rubber bag. A frog's lung is a single, thin bag, about half an inch across it. Each little sac of a man's lung is like a tiny frog's lung. [Illustration: =A frog's lung (×4).=] =101. The diaphragm.=--The lungs fill the upper part of the body just below the neck. They are covered by the bony ribs, and rest upon a broad muscle. This muscle is called the _diaphragm_. It divides the inside of the body into two parts. The upper part is the _chest_, and holds the heart and lungs. The lower part is the _abdomen_, and holds the stomach, intestine, and liver, and a few other parts. [Illustration: =The parts inside the body.= _a_ lungs. _b_ heart. _c_ diaphragm. _d_ stomach. _e_ liver. _f_ intestine.] =102. Breathing.=--When the diaphragm lowers itself, or the ribs are raised, the chest is made larger. Then the air rushes through the nose and swells out the lungs to the size of the chest. This is taking a breath. Then the chest becomes smaller again, and blows the air out. A man breathes about eighteen times a minute. He does not seem to rest in breathing, but as he works only when he takes in breath, he rests one half of the time. =103. How air gets into the blood.=--After the blood has been around the body through the arteries and capillaries and veins, the heart sends every drop to the lungs before it sends it out to feed the cells again. The blood flows through little capillaries upon the sides of the air sacs. There the red blood cells take up some of the air, and carry it with them. When they have a load of air, they become of a brighter red color. The blood in the arteries on its way to the cells is bright red. =104. How the cells get air.=--When the blood reaches the capillaries around the cells of the body, the red blood cells give up some of the air to the cells. Thus each cell of the body gets some air, and so it breathes. The cells cannot reach the air themselves, and so the red blood cells bring it to them. We breathe so as to supply the cells with air. =105. What burning is.=--When meat is put into a hot stove it quickly burns, and passes off in smoke, and leaves only a little ashes. The ashes are the mineral parts of the meat. If the fire is very hot, you cannot see the smoke. The burning of the meat makes heat. Heat in a steam engine makes the machine do work. Every fire must have plenty of air. If air is shut off, the fire goes out. When meat burns, the air unites with the meat and makes smoke, and ashes, and gives out heat. Air unites with something in every fire. =106. Burning inside the body.=--In every part of a man's body a very slow fire is always burning. The blood brings to the cells food from the intestine, and air from the lungs. The food and air join in a burning. The smoke goes back to the blood and is carried to the lungs, and breathed out with the breath. The ashes, also, go back to the blood, and are carried away by the skin and kidneys. The burning makes no flame or light for it goes on very slowly. You cannot see the smoke, but you can feel the warmth of the burning. Some of the heat is turned to power, and gives the body strength to do work. The body is like a steam engine. It burns up all its food. =107. How the body is warmed.=--The body is warmed by the slow burning in the cells. This burning keeps the body always at the same warmth. On a hot summer's day you feel warmer than on a cold snowy morning. But your body is no warmer. Only your skin is warmer. If the skin is warm, the whole body feels warm, but if the skin is cold, the whole body feels cold. On a hot summer's day the heat is kept in the skin, and we feel warm. On a cold winter's day a great deal of heat passes off from the skin, and we feel cold. Yet our bodies have the same warmth in winter as in summer. =108. How the sweat keeps us cool.=--When your hands or feet are wet, they are cold. On a hot summer's day, your body becomes wet with sweat. This cools the body as if water were poured over it. So sweating keeps you from getting too warm, and from being sunstruck. We are sweating all the time, but the sweat usually dries as fast as it forms. When we are too warm it comes out faster than it dries. On a winter's day we sweat only a little, and so we save the heat. But more heat passes off from the skin into the cold air, and we do not grow warmer. =109. Clothes.=--We wear clothes to keep the heat in the body. They do not make heat, but they keep it from going off. Wool and flannel clothes keep the heat in better than cotton. We wear woolen in the winter, and cotton in the summer. Fur keeps in heat the best of all. In very cold lands only fur is worn. Linen lets heat out easily. It makes good summer clothes. =110. Where to wear the most clothes.=--The face and hands are kept warm by the blood and we do not cover them except in the coldest weather. Our feet are more tender and need to be covered enough to keep them warm. We ought to wear thick-soled shoes or rubbers in damp weather so as to keep the feet dry and warm. We ought to dry the stockings every night, for they will get wet with sweat. The trunk of the body needs the most clothes. The legs ought to be kept warm, too. If the dress reaches only to the knee, thick underclothing is needed for the lower part of the leg. Do not keep one part of the body warm while another part remains cold. It is wrong to bundle the neck or wear too much clothing over any part of the body. It is also wrong to wear too little and be cold. When you are moving about, you need less clothing than when you are sitting still. When you have worked until you are very warm, it is wrong to stop to cool off. When you stop, you ought to put on a thick coat or else go into the house. If you do not, you may be chilled and made weak so that you can easily catch cold or some other disease. =111. Heating houses.=--In winter our bodies cannot make heat fast enough to keep us warm unless we put on a great deal of clothing. So we warm our houses. Our grandfathers used fireplaces, but these did not give out much heat. People now use stoves, but some use a furnace in the cellar, or heat the rooms by steam. Some use kerosene stoves, but they are not so good, for they make the air bad. A room should feel neither too warm nor too cold. It is of the right warmth when we do not notice either heat or cold. =112. Change of air.=--After air has been breathed it is no longer fit for use. In an hour or two you would breathe all the air of a small room once if it were not changed. When the air is partly used, you feel dull and short of breath, and your head aches. As soon as you get out of doors, you feel better. Foul air of houses and meeting places often contains disease germs. It is necessary to change the air of all rooms often. You can do this by opening a door or window. It is a good plan to sleep with your bedroom window open, so as to get good air all night. Air passes in and out of every crack in the windows and doors. If only one person is in a room, this may make enough change of air. If many persons are in a room, you will need to change the air in other ways. You can do this by opening a door or window. Do not let the cold air blow upon any one, for it may help to make him catch cold, if the air of the room is impure. If we lower a window from the top, warm impure air may pass out above it without making a draft. [Illustration: =Diagram of the natural ventilation of a room.= The arrows show the direction of the air currents.] You need fresh air at night as much as in the daytime. You need not be afraid of the night air, for it is good and pure like the day air. You ought to sleep with your window open a little. You ought to open the windows wide every morning and air your bed well. At night you ought to take off all your clothes and put on a night-dress. Then hang your clothes up to air and dry. =113. When to air a room.=--When you first enter a room full of bad air it smells musty and unpleasant. But after you have been in the room a while, you get used to it. If, however, you go out of doors a minute and then come back, you will smell the bad air again. If the air smells bad, open a door or window until it is sweet again. =114. How to breathe.=--When you run hard, the cells of your body use up all the air, and then you feel short of breath. While you run, burning goes on faster, and you feel warmer. You can work harder and longer if you can breathe in a great deal of air. You will also feel better and stronger for it. Then if you are sick, you will be able to get well more quickly. You ought to know how to breathe right. _First_, you ought to breathe through your nose. Even when you run, you ought to keep your mouth closed. _Second_, you should try to breathe deeply. You should take a very deep breath often, and hold it as long as you can. By practice you can learn to hold it a full minute. _Third_, you ought to run, or do some hard work, every day. When you get short of breath, you will have to breathe more deeply. After a while you may be able to run a half mile, or even a mile, without getting out of breath. But do not get tired out in your run, for this will harm you. _Fourth_, you must sit and stand with your shoulders back, and your chest thrown forward. A round-shouldered boy cannot have large lungs or be long winded. By breathing right, you can make your lungs very much larger and stronger. =115. The voice.=--We talk by means of the breath. At the upper part of the windpipe is a small box. Its front corner can be felt in the neck, just under the chin, and is called the _Adam's apple_. Two thin, strong covers slide across the top of the box, and can be made to meet in the middle. The covers have sharp edges. When they are near together, and air is breathed out between them, a sound is made. This sound is the _voice_. The tongue and lips change it to form _words_. =116. Care of the voice.=--The voice shows our feelings, even if we do not tell them in words. We can form a habit of speaking in a loud and harsh tone, as if we were always angry, or we can speak gently and kindly. We shall be more pleasant company to others if we are careful always to speak in gentle but distinct tones. [Illustration: =Top view of the larynx, with the vocal cords closed, as in speaking.= _a_ epiglottis. _b_ vocal cords.] [Illustration: =Top view of the larynx, with the vocal cords open, as in breathing.= _a_ epiglottis. _b_ vocal cords.] Shouting strains the voice and spoils its tone for singing. Reading until the throat is tired makes the voice weak. Singing or shouting in a cold or damp air is also bad for the voice. Breathing through the mouth is the worst of all for the voice. =117. What becomes of alcohol in the body.=--When alcohol is taken up by the blood, it is carried to the liver. The liver tries to get rid of it by taking some air from the blood and burning it up, just as it burns the real food of the body. But this takes some air from the cells of the body. Then they do not burn as they should. When a stove gets too little air through its draft, it makes an unpleasant smoke, and cools off. Just so, when the cells of the body do not burn as they should, they produce the wrong kind of smoke and ashes. This poisons the body and makes men sick. The most of the poisoning of alcohol is due to these new poisons. When alcohol takes air from the cells of the body, they do not get enough air. Then they are like a short-winded boy, and do not do their work well. In this way alcohol makes the body weak. Alcohol does not cease to be harmful because it is burned up in the body. It is harmful just because it burns so quickly. Using alcohol in the body is like trying to burn kerosene in a coal stove. The body is not made to burn alcohol any more than a coal stove is made to burn kerosene. You can burn a little kerosene in a coal stove if you are very careful. Just so, men can burn alcohol in their bodies. But kerosene will always smoke and clog up the stove, and may explode and kill some one. So alcohol in the body burns quickly and forms poisons. It always harms the body and may destroy life at once. =118. Alcohol and the lungs.=--If you run a long race, your lungs will need a great deal of air. If you take strong drink, the alcohol will use up much of the air, and you will not have enough to use on your run. So you will feel short of breath, and will surely lose the race. You cannot drink and be long-winded. Two drinks of whisky will use up as much air as the body uses in an hour. It would be easy to smother a person with strong drink. Drunken persons are really smothered; they often die because of the failure of their breathing, even while their heart is able to beat well. Alcohol often causes the lungs to become thickened. Then air cannot easily pass through their sides, and a person suffers from shortness of breath. Sometimes these persons cannot lie down at all, but must sit up to catch their breath. =119. Drinking and taking cold.=--A strong, healthy man can stand a great deal of cold and wet. If he breathes deeply in his work, all the cells of his body get plenty of air, and if he eats good food, the cells get plenty to eat. Then it will take a great deal to harm them. But alcohol hinders the digestion of their food, and also takes away their air. So the cells are both starved and smothered, and are easily hurt. Then a little cold and wet may do great harm to his body, for a drinker cannot stand bad weather or hard work so well as he could if he should leave drink alone. Men often drink to keep themselves from taking cold. The alcohol really makes them more liable to take cold. It causes the blood to flow near the surface of the skin; there it is easily cooled, and the drinker soon becomes chilled; then he feels colder than ever. The cold harms the cells of his body, and then the white blood cells cannot easily fight disease germs. For this reason a drinker easily takes cold and other diseases. =120. Alcohol lessens the warmth of the body.=--Alcohol causes the blood tubes in the skin to become larger. Then more blood will touch the cool air, and the body will become cooler. But because more warm blood flows through the skin, a man feels warmer. But he is really colder. Alcohol makes men less able to stand the cold. Travelers in cold lands know this and do not use it. =121. How tobacco affects breathing.=--We would not live in a room with a smoking stove. But tobacco smoke is more harmful than smoke from a stove, for it has nicotine in it. Tobacco smoke in a room may make a child sick. Cigarette smoking is very harmful to the lungs, for the smoke is drawn deeply into them, and more of the poison is likely to stay in the body. The smoke of tobacco burns the throat and causes a cough. This harms the voice. WHAT WE HAVE LEARNED 1. Air is always being breathed into little sacs inside the body. The sacs form the lungs. 2. The red blood cells pass through the lungs, and take little loads of air. They then carry the air through the arteries to the capillaries. 3. In the capillaries the air leaves the red blood cells, and goes to the cells of the body. 4. The air unites with the cells, and slowly burns them to smoke and ashes. 5. The smoke goes back to the blood, and is carried to the lungs and given off by the breath. The ashes go back to the blood and pass off through the skin and the kidneys. 6. The burning in the cells makes heat. 7. Some of the heat is changed to power, as it is in a steam engine. 8. The heat also warms the body. It keeps it at the same warmth on a cold day as on a hot day. 9. We wear clothes to keep the heat in, and so to keep us warm. 10. The air of a room needs to be changed often. It is made stuffy by our breath. 11. The voice is made by the breath in a box in the neck. 12. Alcohol uses air belonging to the cells of the body. 13. Tobacco smoke has the same poisons as tobacco. It can poison the whole body through the lungs. CHAPTER XI THE SKIN AND KIDNEYS =122. Waste matters.=--The food is burned in the cells. As this burning goes on, the _smoke_ goes off by the lungs and the unburned substances, the _ashes_, go off by the skin and kidneys. The ashes are mostly the minerals of the cells, but there are also some from the burned albumin. All these go back to the blood and are carried to the skin and kidneys. [Illustration: =The skin (×100).= _a_, _b_ and _c_ epidermis. _d_ and _g_ tough and thick part of skin. _e_ sweat gland. _f_ blood tubes. _h_ fat pockets.] =123. The skin.=--The skin covers the whole body. It is strong and keeps the body from being hurt. =124. The epithelium.=--The skin is covered with a thin layer of cells like fine scales. These scales are called _epithelium_, or _epidermis_. They have no blood tubes or nerves and so have no feeling. You can run a pin under them without feeling pain. They are always growing on their under side and wearing off on their upper side. They keep the nerves and blood tubes of the skin from being hurt. =125. The nails.=--The top scales of epithelium at the ends of the fingers become matted together to make the nails. The nails keep the ends of the fingers from being hurt. They can also be used to hold or cut small things. The new parts of the nails form under the skin and push down the older parts. So the nail grows farther than the end of the finger and needs to be cut off. Biting the nails leaves their ends rough. Then they may catch in the clothes and tear into the tender flesh. We ought to keep the nails cut even with the ends of the fingers. The nails are not poisonous, but the dirt under them may be. We ought to keep them clean. Clean nails are one mark of a careful boy or girl. =126. Hair.=--Some of the scales of epithelium over some parts of the body dip into tiny holes in the skin. In each hole they become matted together to form a _hair_. Fine short hair grows on almost every part of the body. On the top of the head it grows long and thick. When boys become men, it also grows long upon their faces. The skin pours out a kind of oil to keep the hair soft and glossy. [Illustration: =A hair (×200).= _a_ the surface of the skin. _b_ a hair. _c_ an oil gland. _d_ a muscle to make the hair stand on end. _e_ and _g_, the growing cells of the hair. _f_ fat in the skin.] =127. Care of the hair.=--The hair may become dirty like any other part of the body. Brushing it takes out a great deal of dirt, but you should also wash it once a week. The oil in the skin ought to be enough for the hair. Hair oils do not do the hair any good. If you wet the hair too often, you may make it stiff and take away its gloss. It is best to comb the hair dry. Brush it so as to spread the oil of the skin. Hair dyes are poisonous, and ought not to be used. =128. The sweat or perspiration.=--The scales of epithelium dip into the skin and there line tiny tubes. The tubes form the _sweat_, or _perspiration_, out of the blood. The tubes are too fine to be seen, but they are upon almost every part of the body. They take the ashes or other waste matter or poisons from the blood and wash them out of the tubes with the perspiration. So the perspiration has two uses. First, it takes heat away from the body (see § 108). Second, it gets rid of the waste matters or ashes of the body. It has very little of these at any one time, but in a day it gets rid of a great deal. =129. The kidneys.=--The kidneys are close to the backbone, below the heart. They are made of tiny tubes much like the sweat tubes in the skin. The tubes take ashes and other waste matters from the blood, also a great deal of water. They also take away poisons and disease germs when we are sick. The kidneys take away about as much water as the skin, but they get rid of very much more poisons and waste matters than the skin does. If our kidneys should stop their work, we should soon die. =130. Need of bathing.=--When the perspiration dries from the skin, it leaves the waste and poisons behind. We cannot always see the dried matters, but they always have an unpleasant odor. We should bathe often enough to keep our body from having an unpleasant smell. We should wash the whole body with soap and hot water at least once a week in winter and more often than that in summer. Another reason for bathing is to wash disease germs from the body. Most dirt has disease germs in it. Disease germs also float in the dust of the air and stick to our skin when we go into a dusty room. If our skin is dirty, some of the germs may be carried into our flesh when our skin is pricked, or scratched, or cut. We sometimes catch boils, or erysipelas, or lockjaw, from very little wounds in a dirty skin. Cleanliness of our skin helps to keep us from catching diseases. =131. Cold baths.=--Sometimes we bathe when we are clean so as to get refreshed. If we bathe in cold water, we feel cold at first. In a little while we feel warm again. Then we feel stronger, and refreshed for work. If we stay in the bath too long, we become cold again and feel weak. When boys go in swimming, they ought to come out before they begin to feel cold. It is a good plan to take a cold bath every morning when you get up, even if you use only a wash-bowl with a little water. It will take only a few minutes, but will keep you clean and make you feel more like doing your day's work. =132. A fair skin.=--We must wash often, to make the skin fair and smooth. Use enough good soap to keep the skin clean. If you eat as you should, and digest the food well, your skin will have the least amount of waste to give off. Then it will look well. A bad looking skin is due to bad food and to bad digestion. If you do not digest your food well, you cannot have a fair skin. Face paint and powder make the skin look worse, for they hinder perspiration. Nothing of that sort will do the skin any good. You must eat as you should, and you must keep clean. Then your skin will be clear. =133. Washing clothes.=--Our clothes rub off a great deal of the perspiration and waste. They become soiled. A great deal of dirt also gets upon the sheets of our beds. Our clothes need to be washed as well as our bodies when they are soiled. Air and the sun as well as water destroy the waste of the body. Our clothes need to be aired at night, and the bed and bedroom should be aired through the day. =134. Slops.=--After water has been used to wash our body or our clothes it is dirty and is not fit to be used again. It must not be thrown where it can run into a well. If a person has typhoid fever or cholera or other catching disease, the water may carry germs of the disease to the well, and so other persons may get it. Slops from the house should not be poured out at the back door, but they should be carried away from the house. In cities the slops are poured into large pipes and tunnels underground. These pipes are called _sewers_. They empty outside the city. =135. Alcohol and the skin.=--Alcohol interferes with digestion and causes biliousness. This makes the skin rough and pimply. A drinker seldom has a clear skin. Alcohol causes the arteries of the face to become enlarged. Then the face is red. A red nose is one of the signs of drinking. When a person uses strong drink he is often uncleanly. He does not care for the bad looks of his clothes and skin, and so he lets them stay dirty. This harms the skin and makes it look bad. The dirt also poisons the skin and may itself be a cause of sickness. Because alcohol poisons the whole body and often produces kidney diseases, the drinker is apt to catch other diseases. Drinkers are the first to catch such diseases as smallpox and yellow fever. Where there are great numbers of cases, the drinkers are the first and often the only persons to die. This is because their skin and kidneys have been harmed by the alcohol and cannot throw off the poisons of the disease. Any kind of sickness will be worse in a drinker. Surgeons do not like to operate on drinkers, for their wounds do not heal so quickly as in other people. When there is too little air, a fire burns slower, and makes a blacker smoke and more ashes. Alcohol takes some air from the cells of the body. So they burn with smoke and ashes of the wrong kind. The skin has to work harder to get rid of these, and sometimes it cannot do it well. Then the body is poisoned. The alcohol is burned and cannot poison the body any more. But it causes the body to make poisons, and so it is to blame. The poisons do great harm to the skin and kidneys. Alcohol causes more kidney disease than all other things put together. WHAT WE HAVE LEARNED 1. Little tubes in the skin are always giving off ashes and waste matters in the perspiration. 2. Perspiration dries on the skin. So the skin must be washed often. 3. The kidneys get rid of more water and waste matter than the skin does. 4. Perspiration also gets upon the clothes and bed sheets. These must be washed too. 5. Dirty water from washing should be thrown out where it cannot run into a well. 6. The skin is thick and strong and keeps the body from being hurt. 7. The skin is covered with a layer of scales. The scales have no feeling. 8. The scales form the nails on the ends of the fingers. 9. The scales also form the hair. CHAPTER XII THE NERVES, SPINAL CORD, AND BRAIN =136. Need of nerves.=--The cells of the mouth, stomach, and intestine digest food; the cells of the liver change the food to blood; the cells of the heart pump the blood to feed all the cells of the body; the red blood cells carry air for the cells to breathe; and the cells of the skin and kidneys carry away the waste of the rest of the cells. Each set of cells works for all the rest. If the cells of the body were only tied together, each one would do as it pleased, and no two would work together. But something tells each cell of the body to work with the others. The cells all obey the mind. A tiny thread goes to each cell of the body. Each thread is a _nerve_. The mind and the cells signal to each other over the nerves. By means of the nerves the mind makes the cells work together. [Illustration: =A nerve thread (×400).= _a_ central conducting fiber. _b_ covering of fat.] [Illustration: =A thin slice for the end of a cut nerve (×200).= _a_ nerve thread. _b_ connective tissue binding the threads into a cord.] =137. Nerve messages.=--The nerve threads run in bundles and form nerves large enough to be seen. The mind uses the nerves to tell the cells to do work. It tells the muscles to move the arms and legs. It tells the heart to beat and stomach to pour out gastric juice; and it tells each of the cells to eat. The cells also send word over the nerves to the mind. They tell the mind when they are touching anything, and whether it is hard, or smooth, or hot, and many other things about it. The cells also tell the mind if they need more food, or are tired. The nerves are always carrying messages to and from the cells. The cells depend upon these messages to tell them when and how to work. If the nerve of any part of the body is hurt or cut, we cannot feel with the part or move it, and its cells do not act in the right way. We do not feel the nerves while they are carrying the messages. We wish the cells of the arm to work, and they work, but we do not feel the message as it goes from the mind to the cells of the arm. [Illustration: =A thin slice from the spinal cord with the cells and nerves magnified 200 diameters.= _a_ cells in the gray matter. _b_ fibers in the gray matter. _c_ nerve threads in the white matter.] =138. The spinal cord.=--The nerves start inside the backbone. The backbone is hollow. It has a soft, white cord inside, as thick as the little finger. Part of the mind lives in this cord. The cord is called the _spinal cord_. Some of the nerves start from cells of the spinal cord. These cells send word to the muscles to move and to all the cells of the body to eat and grow. They also send word to the arteries to carry the right amount of blood to the cells. From the nerves the spinal cord gets word when something hurts any part of the body. You may put your finger on a sharp pin. The spinal cord feels the prick, and quickly sends word to snatch the finger away. So the finger is taken away before you really feel the prick. When some one sticks a pin into you, you cannot help jumping. This is because the spinal cord sends word for you to jump away from the pin before it can harm you much. Thus the spinal cord keeps the body from being hurt. It acts while we are asleep as well as when we are awake. =139. Need of a spinal cord.=--We do not feel the spinal cord acting, and we cannot keep it from acting. It tells the cells when to eat and grow, and it tells the heart and arteries how much blood to send to each cell. If we had to think about feeding an arm or a leg, we should sometimes forget it, but the spinal cord keeps doing it without our thinking of it. We put food into the body, and the spinal cord tells the cells to use it. If it stops acting for an instant, the cells stop work and we die. We cannot change its action by any amount of thinking. [Illustration: =Regions of the head and action of the different parts of the brain.=] =140. The brain.=--The nerves of the body go to the brain as well as to the spinal cord. The brain lies in the top of the head. A hard cover of bone keeps it from getting hurt. It is a soft white mass, and weighs about three pounds. Its outside is made of cells, while its inside is the very beginning of the nerves of the body. =141. The mind.=--The mind is the real man. It is the thinking part of himself. It lives in the body and works by means of the cells of the brain. If these cells are hurt or killed, the body seems to have no mind, but yet it may keep on living. If all the mind leaves the body, the body is dead. By means of the mind we feel, and know, and think. The mind uses each part of the brain for only one kind of work. =142. The senses.=--The cells of the body send word to the brain over the nerves. The eye tells of sight, the ear of sounds, the nose of odors, the mouth of tastes, and the skin of feelings. All these messages go to the back part of the brain. They tell the mind of the news outside of the body. We get all our knowledge in this way. The cells also tell of their need of food and drink by means of the feelings of hunger and thirst. =143. Motion.=--The mind in the cells of the top part of the head sends the orders for moving the different parts of the body. When we wish to run, the mind in the top of our head sends an order over our nerves to our legs, and they carry the body where we wish. If the top part of your brain is hurt, as by a blow, it cannot send orders to move, but you will lie stunned. =144. Memory.=--The mind lays away all its messages, and often looks them over again. These old messages are called _memories_. They always stay with the brain, and the mind can call them up at any time. Our memories make our knowledge. Every act of the mind leaves some mark on the memory. We may not be able to bring it back when we want to, but it will come back some time. Every bad word and evil deed will tend to come back and make us bad again. Every good work and word will leave its memory and make us better. We ought to fill our minds with good memories. =145. Thinking.=--The brain also thinks. Thinking is different from feeling and from moving, but we can think about our feelings and about our movements. The brain just back of the forehead does all our thinking. A dog has only a little forehead, and cannot think much. But the rest of its brain is large, for it can see and hear and run as well as a man. A baby can see and hear and move, but it cannot think until it is taught how. Boys and girls go to school to learn to think. Thinking is work, just as truly as running is work. At school, no one can learn to think without working. Looking at things and hearing some one talk about them will not make you a strong-minded man, but thinking about these things will. Boys and girls should study and think, as well as look around and listen. =146. How thought rules the body.=--We are always feeling and moving. We often do these things without trying, but we must make ourselves think. We can make our bodies move, or keep still, and we can keep from too much feeling. Our thoughts direct our natural desires to move and feel. In an animal, the feelings and movements direct the thoughts. When men let their feelings rule their thoughts, they are like animals. When the thoughts control the feelings and acts, we are men. If you get angry and cry, when you hurt your finger, then you are like an animal; but if you think about it and control your feelings, you are behaving like a strong and noble man. The thought part of the brain ought to rule all the rest. =147. Sleep.=--Most of the brain does its work without our knowing it, but we know when we think. The thinking part of the brain gets tired, like any other part of the body. When it stops work, we are asleep. We must give the brain a rest in sleep, just as we must rest an arm or a leg. We ought to give it regular rest. Every night we ought to go to bed early. Then we shall be ready to get up early and shall feel like working. Boys and girls need nine or ten hours' sleep each day. When they are grown, they need seven or eight hours' sleep each day. The spinal cord and some parts of the brain must always stay awake to make the cells of the body eat and grow. When we are asleep, they must be wide awake, and must repair the worn-out parts. They do not seem to rest at all. If they rested for any length of time, then the lungs, heart, stomach and all other parts of the body would stop work, and we should die. But they really rest a part of the time. Like the heart, they act for a second, and then stop for a second. They seem to act all the time, but in all they rest half the time. =148. Worry.=--The mind can do a great deal of work, if it gets good sleep. If a person gets enough sleep and rest, he cannot harm his mind by hard work. Sometimes the mind is troubled and worried over a danger or a loss. Then it cannot rest, but soon wears itself out. Worry is far more tiresome than hard work. By an effort, we can keep from worrying. It never does us good to worry, and we ought to keep from it. =149. Nervousness.=--The thoughts are able to rule all the rest of the mind. They can keep us from feeling ill-tempered when we cannot have our own way. Sometimes a little unpleasant feeling makes us very unhappy, and keeps us from thinking about our work. A little noise or pain keeps some children from study, while others can bear a great deal without being disturbed by it. Some persons jump at a little noise, and are afraid of a tiny bug or mouse. This is because their feelings rule their thoughts. Such persons are called _nervous_. A nervous person is very uncomfortable and makes others so too. Yet any one can get over the habit of being nervous, if he will try. You ought not to laugh at a nervous person if he is afraid of some little thing while you are not. You should help him to get over his nervousness and to become brave. =150. Fear.=--Some persons are always brave. In danger they calmly stop to think, and then know how to save themselves. A timid person does not think, but rushes where his feelings lead. When a crowd is in danger, all will rush to do one thing. All will run for a door, and perhaps tread on one another. Then some one will surely be hurt. At a fire, or in any other danger, you should always stop to think how to act. If you rush with the crowd, you may be hurt. You will be more likely to be safe, if you stay away from them. Then, if help comes, you will be able to receive it. Besides, if you are cool and brave, you will help others around you to be brave too. =151. Fire drill.=--In schools the children are taught how to go out of the building when there is a fire. A bell is struck when the children do not expect it. Then every child must leave his seat at once and march out of the building. The bell is struck every few days. Then, when the bell really sounds for a fire, the children know how to march out quickly, and so they learn to be brave. By training we can learn to be brave at all times. We fear many harmless things, and in many cases do not fear real dangers. We are liable to be hurt at any time. We are more liable to be hurt by a horse when we are out driving than we are by the dark. Yet we do not fear the horse, while some do fear the dark. We ought to learn to think, so as to control our fear. Some are afraid of the dark, some are frightened by ghost stories, and others expect to see a wild animal jump from behind every bush. No one fears these things unless he has been told about them. We ought to be careful not to tell children of these things. We ought to teach them to control their fear. =152. Habit.=--After we have thought about a thing a few times, its hold on our memory becomes strong, and leads us to think about it often. When we have done a thing a few times, we are likely to do it again without knowing it. We call this doing things over again _habit_. When we once form a habit, we find it very hard to break. We can form habits of doing right or of doing wrong. We can get into the habit of swearing or of drinking by doing these things a few times. Then we shall do these things when we do not want to. When a drinker begins, he does not expect to keep on drinking. But his habit makes him drink, and he cannot help it. We should be careful not to do bad things, for we easily form the habit of doing them. =153. Good habits.=--We can form habits of doing right. We can speak kindly and be generous. Then we shall do these things as easily as others get cross. After a person has tried to do good a few times, he will find it much easier to do good. Then he will speak kindly and give generously just as easily as others get angry and keep their good things to themselves. =154. Alcohol takes away thought.=--Alcohol affects and weakens the cells of the brain sooner than it does those of any other part of the body. It first makes the thought cells weak. Then a person does not think how he acts. He lights his pipe in the barn and throws the match in the hay. He drives his horse on a run through a crowded street. He swears and uses bad language. He gets angry at little things and wants to fight. He seems to think of himself, and of no one else. He is happy, for he does not think of the bad effects of the drink. He has a good time, and does not care for its cost. He likes to drink, because it makes him feel happy. =155. Alcohol spoils motion.=--Some cells of the brain cause the arms and legs, and all other parts of the body, to move. Alcohol next makes these weak. Then a person cannot move his legs right, but he staggers when he walks. He cannot carry a full cup to his lips. His hands tremble, and he cannot take care of himself. He is now really drunk. =156. Alcohol takes away feeling.=--After a man is drunk, he loses the sense of feeling. He does not feel cuts and blows. Because he does not feel tired, he feels very strong. He often sees two things for one, and hears strange noises. The whole brain at last gets weak, and cannot act. Then the drinker lies down in a drunken sleep, and cannot be waked up. Some die in this state. =157. Insanity.=--When the brain is misused by alcohol for some time, it cannot get over it. Then the person becomes insane. Drink sends more persons to the insane asylum than all other causes put together. =158. Delirium tremens.=--If a drinker gets hurt, or becomes sick, he sometimes has terrible dreams. In them he sees dirty and savage animals coming to harm him. These dreams seem very real to him, and he cries out in his fright. This is called _delirium tremens_. A person is liable to die from it. =159. Alcohol harms a drinker's children.=--The children of drinkers are apt to be weak in body and mind. A drinker hurts his children even more than he hurts himself. They are liable to catch diseases, and are often cross and nervous, or weak-minded. It is a terrible thing for a man to make his children weak and nervous. =160. Other bad things about drink.=--There are many other terrible things about drink, besides the harm it does a man's body. Many a man has made himself drunk so as to steal or kill. No man can drink long without becoming a worse man for it. Men will not trust him, and he loses the respect of his friends. Making strong drink takes thousands of men away from good work. They might work at building houses, or raising grain, or teaching school. As it is, their work is wasted. A great deal of money is wasted on strong drink. All the mines of the world cannot produce enough gold and silver to pay the drink bill. The people of the United States pay more for strong drink than for bread. The price of two or three drinks a day would amount to enough, in ten years, to buy a small home. The cost of strong drink is made much greater if we count the cost of jails and insane asylums. Over one half of all crimes and cases of insanity are caused by strong drink. We must also add the misery and suffering of most children of drunken fathers. This loss cannot be counted in money. Numbers of children become truants from school and learn theft and falsehoods from lack of a father's care. When all the cost is counted, nothing will be found so expensive as strong drink. On the other hand, what do people get for their money and suffering? They get only a little pleasure, and then they are ashamed of it. Men use strong drink only because they like it more than they dislike its bad effects. Since drink does a great deal of harm, with no good to any one, it is right to make laws to control its sale. =161. How tobacco affects the brain.=--Some men smoke to make themselves think, and some to keep themselves from thinking. Now, smoking cannot do both things. It really makes the brain less able to think, for it weakens the whole body. A school-boy's brain will surely be harmed if he uses tobacco at all. WHAT WE HAVE LEARNED 1. The mind makes all the cells of the body work together. 2. Tiny nerve threads carry messages from the mind to the cells. 3. Most of the nerves begin at the spinal cord in the backbone. 4. The mind in the spinal cord tells the cells to eat and grow. It tells the arteries how much blood to carry to the cells. 5. The cells tell the spinal cord if they need food, or if something suddenly hurts them. The spinal cord sends word to snatch the part from danger. 6. Nerves carry to the brain news of sight, sound, odor, taste, and touch. 7. The brain sends word to the muscles to move the arms, the legs, and the rest of the body. 8. The brain thinks. 9. The brain stores up all its messages; these make memory and knowledge. 10. The thought part of the brain can control the feelings and the movements of the body. 11. Alcohol is more harmful to the brain than to any other part of the body. CHAPTER XIII THE SENSES =162.= A man has five ways of knowing about things outside of the body. He can feel, see, hear, smell, and taste. =163. Feeling.=--Nerves go to nearly every cell in the body. They carry news to the brain when anything touches them. The news produces a feeling. Feelings are of three kinds:-- _First_, when anything touches the cells without harming them, we feel a _touch_. We feel a touch by nerves in the skin. Those in the ends of the fingers and tongue can feel the best. Those upon the back give but little feeling. Touch tells whether anything is hard, or rough, or round, or square, or has other qualities and shapes. _Second_, when anything touches the bare nerves or hurts the cells, we feel a _pain_. We can feel a pain anywhere in the body. Pain tells us if we are being harmed. If we had no feeling of pain, we might be killed before we could know of our danger. Pain warns us away from danger. _Third_, we can feel _heat_ and _cold_. Anything very hot or very cold, however, makes only a pain and gives no feeling either of cold or of heat. =164. Sight.=--We see with our eyes. An eye is a hollow ball. In its front is a clear window. Behind the window is a round curtain with a round hole in its middle. When we speak of the color of the eye, we mean the color of this curtain. Light passes through the hole in the curtain and falls upon some nerves in the back of the eyeballs. There it forms a picture like a photograph. The nerves carry this picture to the brain, and we see it. [Illustration: =The human eye.= _a_ bony case of the eye. _b_ muscle to move the eye. _c_ and _d_ coverings of the eye. _e_ lining or seeing part of the eye. _f_ eyelid. _g_ colored curtain or iris. _h_ and _i_ clear windows of the eye.] =165. Movements of the eyes.=--We can turn our eyes so as to look in any direction. Sometimes a person has one eye turned sidewise. Such a person is cross-eyed, and sees well out of only one eye at a time. Glasses may help the eyes, but sometimes a surgeon has to cut a tiny muscle. =166. Coverings of the eyes.=--The eyeballs lie in a bony case, upon a soft bed of fat. In front each is covered with two lids. We can shut the lids to keep out dust and insects. When we are sleepy, they come together and cover the eyes. Little hairs at their edges help to keep out the dust. Sometimes a little dirt gets under the lids. Then the eye smarts or itches, and we want to rub it; but this may grind the dirt in deeper. Then you should get some one else to lift your eyelid and pick out the dust with a soft handkerchief. If you cannot get help, lift the lid by the eyelashes; blow your nose hard, and the tears may wash the dirt away. Dust and disease germs may get into our eyes and make them sore and red. You should bathe your eyes well every time you wash your face. You should use a clean towel, for a dirty one may carry disease germs to your eyes. Some forms of sore eyes are catching. If any one has sore eyes, no one else should use his towels or handkerchiefs. =167. Tears.=--Clear salt water is always running over the eyes and down a tube into the nose. The use of this water is to bathe the eyes and keep them clean. It sometimes runs over the lids in drops called _tears_. =168. How to use the eyes.=--If using your eyes makes them painful or gives you a headache, you are straining your eyes. Facing a bright light strains the eyes. Shade your eyes while you study. A cap may be used as a shade if you cannot get anything else. Never try to look at the sun or a very bright light. You should have the light at one side or behind you. The light should be steady. Reading in a dim light will harm the eyes. =169. Near sight.=--If you cannot read without holding your book less than a foot from your eyes, you are nearsighted, and should wear glasses all the time. If you do this, your eyes may be strong, and you may be able to see well. =170. Far sight.=--If you cannot read without holding your book at arm's length, you are farsighted and need glasses. Most old persons are farsighted. =171. Alcohol and the eyes.=--Alcohol makes the eyes red. It weakens the eyes and may produce blindness. A drunken person often sees double. =172. Tobacco= causes dimness of sight and sometimes produces blindness. =173. Hearing.=--We hear with the ears. Sound is made by waves in the air. The part of the ear on the outside of the head catches the air waves and throws them inside the ear. These air waves strike against a little drum. Three little bones then carry the waves on to nerves farther inside the head. Animals can turn their ears and catch sound from any direction. [Illustration: =Diagram of the ear.= _a_ outer ear. _b_ drum head. _c_ _d_ and _e_ bones to carry sound to inner ear. _f_ _g_ and _h_ inner ear. _i_ tube to the mouth. _j_ middle ear.] =174. Ear wax.=--Wax is formed just inside the ear. It keeps flies and insects from crawling into the ear. Boys in swimming sometimes get cold water into their ears. This may make them have an earache. =175. How the throat affects the ear.=--An air tube runs from the inside of the ear to the mouth. Sometimes when you blow your nose, you blow air into the ear. This makes you partly deaf and you hear a roaring in your ears. Sometimes when you have a cold in your throat, this little tube is stopped. Then your ear may ache and may even discharge matter. This may make you somewhat deaf. Earache and deafness are most often due to a cold in the throat and a stoppage of this tube. Many little boys and girls are deaf and do not know it. They cannot hear the teacher well, and sometimes the teacher thinks they are bad or careless because they do not answer. =176. Care of the ears.=--Very loud noises may harm the ear and make you deaf. When you expect a very loud noise, put your fingers in your ears to shut out the sound. Boxing the ears may break their tiny drums and make you deaf. Do not get cold water in your ear. This may cause an earache and make you deaf. If you get water in your ear while you are in swimming, turn your head to one side and shake it. This will get the water out. Do not put cotton or anything else into your ears. =177. Smell.=--We smell with the nose. Some things give out a vapor to the air. When we draw the air into the nose, this vapor touches the nerves, and we perceive a smell. The nerves are high up in the nose. In order to perceive smell clearly, we sniff the air far up the nose. =178. Use of smell.=--Bad air and spoiled food smell bad. A bad smell is the sign of something spoiled. The sense of smell tells us when food or air is unfit for use. Some people try to hide a bad smell with perfumery. To do this only makes the danger greater, for then the smell does not tell us of the danger of food or air. Some animals can smell much better than a man. A dog will smell the track of a wild animal hours after it is made. Savages can smell much better than civilized men. =179. Taste.=--We taste with the tongue. Dry food has no taste, but it must first dissolve in the mouth. Spoiled food tastes bad. Bad-tasting food is not fit to eat. Taste tells us whether food is good or bad. We can learn to like the taste of harmful things. At first no one likes tobacco or strong drink, but the liking is formed the more one uses these. We ought to be careful not to begin to use such things. _Alcohol_ and _tobacco_ burn the mouth and harm the taste. Food does not taste so good and we may eat spoiled food and not know it. WHAT WE HAVE LEARNED 1. We can feel in every part of the body, but mostly in the ends of the fingers. 2. Light makes a picture upon the nerves inside of the eye. 3. If the eyes ache, the light should be softened or the position of the book or work changed, or else the eyes should be rested. 4. Sound in the air goes into the ear and strikes against a drum. Bones then carry the sound to the ear nerves. 5. Air snuffed up the nose gives the sense of smell. Smell tells us if the air or food is fit for use. 6. Taste tells us whether food is fit for use. Men can learn to like the taste of wrong things like tobacco or alcohol. [Illustration: =The Human Skeleton, showing position of bones.=] CHAPTER XIV BONES AND JOINTS =180.= Bones make the body stiff and strong, and give it shape. Long bones reach through the arms and legs, and little bones reach down the fingers and toes. Rounded plates of bone form the head, and a pile of bony rings makes up the backbone. Each bone is built to fit exactly into its own place and to do its own work. In all there are over two hundred bones in the body. They form one seventh of its weight. =181. Form of bones.=--A bone is not like a solid piece of timber, but is hollow like the frame of a bicycle. This makes it strong and light. At its ends a bone is like a hard sponge covered with a firm shell. This makes it too strong to be easily crushed, and keeps it light. A bone grows like any other part of the body. It is made of living cells like woven threads. Lime is mixed among the cells, and makes them stiff like starch among the threads of a linen collar. Blood tubes go through every part of the bone so as to feed the cells. The living cells form one third of the bone, while the lime forms two thirds. =182. Broken bones.=--Bones are very hard, and yet they can bend a little without breaking. Most of them are curved a little, and so they will spring instead of breaking when they are pressed hard. But sometimes they break. Then a person must wear a splint and bandage to keep the bones in place until they grow together again. The living cells will mend a bone in about a month. An old person's bones are more tender than a child's, and will not spring much without breaking. An old man is afraid of falling and breaking his bones, while a child falls a dozen times a day without danger. The bones of some children bend too easily. When they stand, the bones of their legs bend a little. After a while they grow in the crooked shape, and the child is bow-legged. =183. Joints.=--Some bones are hinged upon each other. A bone hinge is a _joint_. The rings of the backbone are held together by very tough pads of flesh. Each pad lets the backbone bend only a little, but altogether they let us bend our backs in any direction. These pads are like rubber springs in a wagon, and keep our bodies from being jarred too much. The finger and toe joints, the wrists and ankles, the elbows and the knees, bend back and forth like a hinge. Tough bands of flesh bind the bones together. The ends of the bones are rounded and smooth. They fit together and make perfect hinges. The joints are oiled by a fluid like the white of an egg. In old people this fluid sometimes dries up. Then the joints become stiff, and creak like a squeaking hinge. [Illustration: =Hinge joint of the elbow.= 1 humerus 2 ulna] The shoulders and hips can be moved in every direction. The upper ends of the arm and leg bones are round like half a ball. They fit into cups on the shoulder and hip bones. They are very smooth, and are oiled like the hinge joints. The joints are made to work very smoothly and easily. =184. Bones out of joint.=--When the ends of bones are torn away from each other, the bone is out of joint. Then the bone cannot be moved without great pain. It should be put back in place at once and kept there by splints and bandages. A person is less liable to have his joints out of place than he is to have his bones broken. =185. Sprains.=--Sometimes a joint is turned too much. This stretches the flesh around the joint, and makes it very tender and painful. This is a _sprain_. When you sprain a joint, you should put it in hot water for an hour or two. Then keep it still for a few days. =186. Why bones and joints grow wrong.=--While bones and joints are growing they can be made to take any shape we please. They cannot be bent all at once, but if we hold them in one way much of the time, they will keep that shape. Some boys and girls sit with their backs bent forward and lean against the desk as if they were too lazy to sit up. When they grow up, they will be bent and round-shouldered. You should sit and stand straight. Then you will grow tall and straight and strong. A soldier has square shoulders and walks erect because he is drilled until his bones and joints grow in the proper shape. As you stand straight with your feet together, your two big toes, your two ankles, and your two knees should touch each other. If you wear tight shoes and press the toes out of shape, they will soon grow so. Nearly every one's feet are out of shape from wearing short, pointed shoes. Your toes should be straight and not cramped by the shoe. If you wear narrow shoes, you may harm your feet. It is better to have one's feet useful, even if they are large, than to make them small and useless. WHAT WE HAVE LEARNED 1. Bones make the body stiff, and give it form. 2. Some bones are long, some round, and some flat. All are hard and springy. 3. Some bones are hinged together. The hinge is a joint. 4. The ends of bones in joints are rounded and smooth, and are oiled with a liquid like the white of an egg. 5. Some bones are bound together by springy pads, as in the backbone. 6. Bones can be broken. They will grow together again themselves. 7. Joints can be put out of place; then we must put them back. 8. If joints or bones are kept in wrong positions they will grow into bad shapes. Tight shoes deform the feet. [Illustration: =The muscular system.=] CHAPTER XV MUSCLES =187. Shape of muscles.=--Bones are covered with muscles. Muscles give shape to the body, and move it about. One half of the body consists of muscles. These are arranged in bundles, and each causes a bone to make one motion. There are over four hundred separate bundles of muscle in the body. One end of a muscle is large and round and is fast to a bone. The other end tapers to a strong string or tendon. The tendon passes over a joint, and becomes fast to another bone. You can easily feel the tendons in the wrist and behind the knee. [Illustration: =Muscle cells, cut across (×200).= _a_ muscle cell. _b_ connective tissue binding the cells together.] A muscle is made of tiny strings. You can pick them apart until they are too fine to be seen with the eye. Each string is a living muscle cell. It is the largest kind of cell in the body. You can see the fine strings in cooked meat. [Illustration: =A thin slice of a voluntary muscle, cut lengthwise (×100).= _a_ muscle cell. _b_ capillaries surrounding the cells. _c_ connective tissue binding the cells together.] =188. How muscles act.=--A nerve runs from the brain, and touches every cell of the muscle. When we wish to move, the brain sends an order down the nerve. Then each muscle cell makes itself thicker and shorter. This pulls its ends together, and bends the joint. We can make muscle cells move when we wish to, but we cannot make any other kind of cell move. We make all our movements by means of our muscles. =189. Where you can see muscles.=--In a butcher's shop you can see lean meat. This is the animal's muscle. White and tough flesh divides the tender red meat into bundles. Each red bundle is a muscle. You will see how the muscle tapers to a string or tendon. The butcher often hangs up the meat by the tendons. You can see the muscles and tendons in a chicken's leg or wing when it is being dressed for dinner. Roll up your sleeve to see your own muscles. Shut your hand tight. You will see little rolls under your skin, just below the elbow. Each roll is a muscle. You can feel them get hard when you shut your hand. You can feel their tendons as they cross the wrist. Open your hand wide. You can see and feel the tendons of the fingers upon the back of the hand. These tendons come from muscles on the back of the arm. You can feel the bundles of these muscles when they open the fingers. There are no muscles in the fingers, but all are in the hand or arm. You cannot open your hand so strongly as you can close it. =190. Strength of muscle.=--By using a muscle you can make it grow larger and stronger. If you do not use your muscles they will be small and weak. Children ought to use their muscles in some way, but if they use them too much, they will be tired out. Then they will grow weaker instead of stronger. Lifting heavy weights, or running long distances, tires out the muscles, and makes them weaker. Small boys sometimes try to lift as much as the big boys. This may do their muscles great harm. =191. Round shoulders.=--The muscles hold up the back and head, and keep us straight when we sit or stand. A lazy boy will not use his muscles to hold himself up, but will lean against something. He will let his shoulders fall, and will sit down in a heap. Sometimes he is made to wear shoulder braces to keep his shoulders back. This gives the muscles nothing to do, and so they grow weaker than ever. The best thing to do for round shoulders is to make the boy sit and stand straight, like a soldier. Then he will use his muscles until they are strong enough to hold his shoulders back. =192. How exercise makes the body healthy.=--When you use your muscles, you become warmer. Your face will be red, for the heart sends more blood to the working muscle cells. You will be short of breath, for the cells need more air. You will eat more, for your food is used up. Your muscles are like an engine. They get their power from burning food in their own cells. When they work they need to use more food and air. So working a muscle makes us eat more and breathe deeper. The blood flows faster, and we feel better all over. The muscle itself grows much larger and stronger. If we sit still all day, the fires in our bodies burn low and get clogged with ashes. We feel dull and sleepy. If we run about for a few minutes, we shall breathe deeply. The fires will burn brighter. Our brains will be clearer, and we shall feel like work again. Boys and girls need to use their muscles when they go to school. Games and play will make you get your lessons sooner. =193. How to use the muscles.=--You should use your muscles to make yourself healthy, and not for the sake of growing strong. Some very strong men are not well, and some men with small muscles are very healthy. Some boys have strong muscles because their fathers had strong muscles before them. Strength of muscle does not make a man. You ought to have healthy muscles. Then your whole bodies will be healthy, and you can do a great deal of work. You ought to learn how to use your muscles rather than how to make them strong. An awkward and bashful boy may be very strong, but he cannot use his muscles. A boy is graceful because he can use them. The best way to use your muscles is in doing something useful. You can help your mother in the house and your father at the barn. You can run errands. You can learn to use carpenter's tools or to plant a garden. Then you will get exercise and not know it. You will also be learning something useful. Play is also needed. Work gets tiresome, and you will not want to use your muscles. Play is bad when it takes you from your work or when you hurt yourself trying to beat somebody. =194. Alcohol and the muscles.=--Men use alcohol to make themselves strong. It dulls their weak feelings, and then they think themselves strong. They are really weaker. The alcohol hinders digestion and keeps food from the cells. Then the fires in the body burn low, and there is little strength. Alcohol sometimes causes muscle cells to change to fat. This weakens the muscles. Men sometimes have to do hard work in cold countries; and at other times they must make long marches across hot deserts. Neither the Eskimos in the cold north, nor the Arabs in the hot desert, use strong drink. Alcohol does not help a man in either place. It really weakens the body. The government used to give out liquor to its soldiers; but soldiers can do more work and have better health without liquor and it is no longer given out. A few years ago men were ashamed to refuse to drink. Even when a new church building was raised, rum was bought by the church and given to the workmen. Farmers used to give their men a jug of rum when they went to work. Farm hands would not work without it. Now all this has changed. Men do not want drinkers to work for them. A railroad company will discharge a man at once if he is known to drink at all. A man can now refuse to drink anywhere and men will not think any less of him. =195. Tobacco= poisons the muscle cells and makes them weak. At first it makes boys too sick to move. It always poisons the cells even if they do not feel sick. =196. A long life.=--A man's body is built to last eighty years, but only a few live so long. If you are careful in your eating and drinking, if you breathe pure air, and if you use your muscles, your body will be healthy and will last the eighty years and more. All through your life you will be strong and able to do good work. WHAT WE HAVE LEARNED 1. Muscles cover the bones and move the body. 2. Muscle is lean meat. It is made of bundles of cells like strings. Nerves from the brain touch each cell. 3. Each muscle is fast to a bone. It becomes a small string or tendon at the other end. The tendon crosses a joint and is fast to another bone. 4. When we wish to move, the brain sends an order to the muscle cells to make themselves thicker and shorter and so bend the joint. 5. You can feel the muscles and tendons in the arm and wrist. 6. Muscle work makes us breathe deeper, and eat more food. It makes the blood flow faster. So it makes our whole bodies more healthy. 7. Every one ought to use his muscles some part of the day. 8. Alcohol and tobacco lessen the strength of the muscles. CHAPTER XVI DISEASE GERMS =197. Catching diseases.=--Our body may get out of order like a machine. Some parts of it may be cut, or broken, or worn out, or hurt in other ways. Then we are sick until it is made whole again. Sickness always means that a part of the body is out of order. Some kinds of sickness are like a fire. A small bit of something from a sick person may start a sickness in us, just as a spark may set a house on fire. Then we may give the sickness to others, just as a fire may spread to other houses. If a person has measles, we may catch the measles if we go near him; but if a person has a toothache, we cannot catch the toothache from him. So we may catch some kinds of diseases, but we cannot catch other kinds. =198. Bacteria and germs.=--Every kind of catching sickness is caused by tiny living things growing in our flesh and blood. Some of them are tiny animals. Most of them are plants, and are called _bacteria_ or _microbes_. A common name for all of them is _germs_. The word germ means nearly the same as the word seed. Bacteria are so small that we cannot see them unless we look at them through a strong microscope. Then they look like little dots and lines (p. 54). A million of them could lie on a pin point; but if they have a chance, they may grow in numbers, so that in two days they would fill a pint measure. Very many kinds of bacteria and other germs are found nearly everywhere. They are in the soil and in water, and some float in the air as dust. When they fall on dead things, they cause _decay_ or _rotting_. When we can fruit, we kill the germs by boiling the fruit and the cans. Then we close the cans tightly so that no new germs can get into them. The fruit will then keep fresh for years. Decay is nearly always a good thing, for by it dead bodies and waste substances are destroyed and given back to the ground, where plants feed upon them. Many plants would not grow if they could not feed upon decaying things. So most bacteria and other germs are useful to us. But some kinds of germs will grow only in our bodies, and these kinds are the cause of most of our sickness. =199. Germs of sickness.=--We catch a sickness by taking a few of the germs of the sickness into our flesh. There they grow quickly, like weed seeds in the ground, and form crops of new germs within a few hours. After a few days the germs become millions in number, and crowd the cells of our flesh, just as weeds may crowd a potato plant (p. 54). Disease germs in the body also form poisons, just as some weeds in a field form poisons. The poisons make us sick, just as if we had swallowed the leaves of a poisonous weed. =200. Fever.=--If a sickness is caused by disease germs, the body is nearly always too warm. Then we say that the sick person has a _fever_. Almost the only cause for a fever is disease germs growing in the body. We can make a person have any kind of fever by planting a few of the germs of the fever in the right part of his body. We are made sick by the germs of fevers more often than by all other causes put together. Here is a list of common diseases caused by fever germs:--colds and sore throats, most stomach aches, blood poisoning in wounds, boils and pimples, tuberculosis, whooping cough, measles, chicken pox, diphtheria, scarlet fever, typhoid fever, smallpox, and malaria. Which of these kinds of sickness have you had? What sickness have you had besides these? =201. Sickness and Dirt.=--Disease germs leave the body of a sick person in three ways: first, through the skin, second, through the kidneys and intestines, and third, through the nose and throat. In these same ways our body gives off its waste matters. If we did not take anything from another person's body into our own body we should not catch fevers. Whatever a feverish person soils may contain disease germs. When a person has only a slight fever he often keeps at work, and then he may scatter disease germs wherever he goes. So disease germs are likely to be found wherever there is dirt or filth. Cleanliness means good health as well as good looks. =202. Disease germs in the skin.=--Disease germs may often be found in sores and pimples on the skin, but they will not leave anybody's flesh and blood through sound and healthy skin. If our skin is smooth and fair, there will be few disease germs on it unless we rub against something dirty. A dirty skin nearly always contains disease germs. Washing and bathing our body will take disease germs from our skin and help us to keep well. =203. Disease germs in slops.=--A great many disease germs leave the body through the intestine and kidneys, and may be found in the slops and waste water of our houses. Slops are dangerous to health, for they may run into a well, or spring, or river, and so carry disease germs into our drinking water (p. 27). Also, house flies may light on the pails or puddles and carry the germs to our food. In these ways we catch typhoid fever, stomach aches, and other diseases of the intestines. All slops and waste matters from the body should be put where they cannot reach our drinking water, and where flies cannot crawl over them (p. 80). =204. Disease germs from the nose and throat.=--If a person is sick with a fever, many of the germs are likely to be found in his nose and throat. Thousands of them are driven out with every drop of saliva and phlegm when he blows his nose, or spits, coughs, or sneezes, or talks. If he puts anything into his mouth, it will be covered with germs. More diseases are spread from the nose and mouth than in any other way, for we are always doing something to spread bits of saliva and phlegm. =205. Spitting.=--Colds and consumption and other forms of sickness are often spread by sick persons spitting on the floor or pavement. The germs become dried and are blown away as dust. For this reason dust from the streets of cities and in crowded halls is often the cause of sickness. In many places spitting on a floor or pavement is strictly forbidden by law. =206. Putting things in the mouth.=--Many persons have the habit of sucking their fingers, or of touching a pencil to the tongue when they write or think, or of wetting their fingers with their lips when they turn the leaves of a book. In all these ways we may give a disease to others or may take a disease from some one else. =207. Public drinking cup.=--When you touch your lips to a cup, you leave some saliva and cells from your mouth on the cup. If a cup is used by a number of persons, some one is almost sure to leave germs of sickness on it, and others are likely to take them into their own mouths when they drink. So a public drinking cup is a dangerous thing. Each school child should have his own cup. Public drinking fountains should be so made that we may drink by putting our lips to a stream of running water. [Illustration: =A safe drinking fountain.= A stream of water gushes up from the middle of the cup.] [Illustration: =An unsafe drinking place.= Photograph taken in the basement of a schoolhouse.] =208. Sweeping.=--Dusty air in a room is dangerous to health, for disease germs are likely to be found in it. We can get rid of dust by keeping our floors swept clean. After sweeping we should wipe the dust from the tables and furniture. A feather duster or dry cloth will only stir up the dust and make it float in the air again. We should use either a damp cloth, or a dry duster made of tufts of wool, so that the dust will stick to the duster. [Illustration: =House fly, magnified.= The hairs on its body and legs catch dirt and disease germs.] =209. Foul air.=--If we live in a closed room, the air soon becomes foul and dusty, and is likely to have disease germs in it. Foul air is one of the greatest of the causes of sickness. We should change the air of a room often so as to keep it fresh and free from dust and disease germs (pp. 65-67). =210. House flies.=--House flies come from garbage heaps and filth of all sorts. So they carry disease germs on their bodies. They light on our food and on our faces, and so they often make us sick. They are often the cause of typhoid fever, stomach aches, and stomach sickness in babies. [Illustration: =Life history of house flies.=] Flies are hatched in manure piles and garbage heaps. At first they look like white worms, and are called _maggots_. Every maggot is a young fly. We can get rid of flies by cleaning up every garbage heap and manure pile. [Illustration: =Young mosquitoes hanging head downward in water.=] =211. Mosquitoes.=--Mosquitoes carry malaria and yellow fever from sick persons to the well. If there were no mosquitoes, there would be no malaria or yellow fever. Mosquitoes are hatched in water, and the young are called _wigglers_. We may often see them in rain barrels. We may get rid of mosquitoes by emptying all rain barrels and pails and cans of dirty water, at least once a week, and by drying up swamps and marshes. WHAT WE HAVE LEARNED 1. We catch a fever by taking disease germs into the body. 2. Disease germs cannot be seen without a strong microscope. 3. The germs may be found in dust and dirt. 4. Slops from our houses are often full of the germs. 5. You may take germs into your body by putting pencils and other things into your mouth, and by drinking from a public drinking cup. 6. Spitting on the floor or pavement may scatter disease germs. 7. House flies and mosquitoes often spread diseases. CHAPTER XVII PREVENTING SICKNESS =212. How our body kills disease germs.=--We take disease germs into the body in three ways: first, through the mouth, second, through the nose, and third, through the skin. So we should watch the purity of our food, drink, and air, and should be careful about putting things into the mouth, and about the cleanliness of the skin. We often take a few disease germs into the body without catching a disease. This is because the white cells of our blood fight the germs and kill them (p. 53). If the body is hurt or weakened, the white blood cells may also be weakened so that they cannot kill the germs. We should take good care of the body so that every part of it may do its work well. We need not be able to run fast, or to lift heavy weights, but the best sign that every part of the body is in good order is to feel bright and wide-awake. Then our white blood cells will also be in good order and able to fight disease germs. =213. Catching cold.=--When we catch a disease, we often say that we have caught cold. We used to think that cold air and dampness were almost the only causes of taking cold, and this is the reason why we called many kinds of sickness by the name of colds. Now we know that we catch cold by taking disease germs into the body. The germs will not be able to grow unless the body is weakened in some way, as by cold and dampness. Yet if we are wet and cold, we shall not catch cold unless we take disease germs into the body. We do not get the germs from the outdoor air, for very few germs are there. We get them from the foul air of our houses when we come in to warm and dry ourselves. If the air of our houses were always as clean and pure as the outdoor air, we should hardly ever have colds. We can safely let the cold air blow on us if we are out of doors, but if we sit in a house, a small draft sometimes seems to make us take cold. This is because there are likely to be many disease germs in the house and few out of doors. Other things besides cold air and dampness may weaken the body, and so help us to take cold. If germs of colds are in a warm room, we may sit there and take cold even if we are not wet or chilled at all. The body may be weakened by poor food, wrong eating, or overwork, so that disease germs will easily grow in it. We take as many colds from these causes as from cold air and dampness. =214. Kinds of colds.=--A person takes most of the germs of colds through his nose and mouth. If they grow only in his nose, we say that he has a cold in his head. If they grow in his throat, he has a sore throat, or tonsillitis. If they reach as far as the upper part of his windpipe, he is hoarse, or has a cough, or the croup. If the germs are planted in his lungs, he may have bronchitis or pneumonia. All these kinds of sickness often spread from one person to another. If one person in a family has a cold, others in the family often catch cold from him. =215. Diseases like colds.=--Diphtheria, tuberculosis, whooping cough, and measles all begin like a common cold and often look like a cold during the whole sickness. Colds do not turn into any of these diseases, for each of them comes from its own germ, just as corn comes only from seed corn. =216. Curing a cold.=--If you have a cold, you ought to stay at home and rest, or lie in bed. Then your white blood cells can gain strength to fight the disease germs. You ought to have plenty of fresh air in your room. You ought not to eat much food for a few days, so that your stomach and intestine and liver can use all their strength in throwing off the poisons of the germs. But you ought to drink plenty of water, so as to help wash away the poisons from your body. =217. Keeping colds from spreading.=--You should keep away from other persons while you have a cold, or other catching disease, so as to keep from spreading the sickness. You ought not to go visiting, or go to school, or to church, or to other meeting places. When you cough or sneeze, you should hold a handkerchief to your mouth, so as to keep from blowing disease germs from your throat and nose. You ought to sleep in a bed by yourself, so that no one may take the disease germs from your bedclothes. No one else should use your towel, or handkerchief, or knife, or fork, or spoon, or dish, until they have been washed in hot water, so as to kill the disease germs on them. =218. Keeping from catching cold.=--You can keep yourself from catching cold by keeping your body strong and in good order. You should keep your clothes dry, eat good food, breathe pure air, get good rest and sleep, and keep your body, your clothes, and your house clean. You should also keep disease germs out of your body. You should not form a habit of putting your fingers or a pencil to your mouth (p. 127). You should keep your nose, your throat, and your mouth clean. =219. Cleanliness of the nose.=--The inside of the nose is wet with a slippery liquid. If you have a cold, the liquid is thick and stops your nose, and is called _phlegm_. The liquid catches and holds dust and disease germs, and keeps them from going into the windpipe. It also kills many of the disease germs. You should always carry a handkerchief and use it so as to blow the germs out of your nose. You should have a clean handkerchief every day. [Illustration: =Photograph of model of the nose and throat.= _A._ tonsil; _B._ adenoids; _C._ opening of Eustachian tube.] =220. Adenoids and large tonsils.=--Sometimes children have large tonsils growing in the back of the throat, or soft bunches of flesh called _adenoids_ back of the nose. These children cannot breathe well through the nose, but must breathe through the mouth. Then they take dust and disease germs deep into the body, and so take colds and other sickness easily. If a child has adenoids or large tonsils, an operation should be done to take them out. =221. Cleanliness of the mouth.=--We often breathe dust and disease germs into the mouth or snuff them into the throat from the nose. Then they are caught between the teeth and in the folds of the cheeks and throat. There they may grow, and finally go deeper into the body and make us sick. A dirty mouth is very often the cause of colds and other sickness. We should keep our mouths clean by brushing our teeth with a toothbrush two or three times a day. We should also rub the toothbrush over the tongue and around the back part of the throat so as to clean the germs from every part of the mouth. Each child should have a toothbrush of his own, and should use it every day. =222. Contagious diseases.=--Diphtheria, whooping cough, measles, scarlet fever, and smallpox are all dangerous kinds of sickness, and spread with great ease. The germs may float in the air, and we may take them into our bodies if we go into a room where any one has the sickness. So we call these diseases _contagious_. If a person has one of these diseases, he should be made to stay in a house or room by himself until he is well. Keeping the sick away from well persons is called _quarantine_. When the sickness is cured, the sick room and everything in it should be cleaned and washed so as to kill the germs. =223. Board of health.=--There is a board of health in every city and town. The men on the board show persons how to keep diseases from spreading, and make them obey the rules of health. Everybody in a town should help the board of health in every possible way. WHAT WE HAVE LEARNED 1. The white blood cells of our body kill disease germs. 2. We catch cold by taking disease germs into our body. 3. The germs of colds are not often found in the air out of doors. They are often found in the foul air of houses. 4. If a person has a cold, he should keep away from other persons, so as to keep from spreading the sickness. 5. Cleansing the nose helps us to keep from catching cold. 6. Cleansing the teeth and the inside of the mouth removes many disease germs. 7. Adenoids and large tonsils should be taken from the throat by an operation. 8. If a person has a dangerous contagious disease, he should be quarantined. 9. Boards of health have charge of the prevention of contagious diseases. INDEX Abdomen, 60. Adam's apple, 68. Adenoids, 136. Air, 59, 65, 129. Albumin, 10, 17, 18, 49. Alcohol, 38. Alcohol and arteries, 56. biliousness, 46. bitters, 46. blood, 55. brain, 95. breathing, 70. burning, 69. catching cold, 71. character, 97. cooking, 47. delirium tremens, 96. digestion, 46. eyes, 103. feeling, 95. habit, 44. heart, 56. heat, 72. heredity, 96. insanity, 96. Jamaica ginger, 47. kidneys, 81. liver, 46. lungs, 70. medicine, 47. money waste, 97. motion, 95. muscles, 119. sickness, 82. skin, 81. stomach, 45. strength, 56, 120. strong drink, 40. suffering, 97. taste, 107. thirst, 44. thought, 95. Alcohol, use of, 39. Ameba, 7, 52. Appetite, 27. Arteries, 51, 55. Ashes, 12, 62, 78. B Bacteria, 123. Bathing, 78, 126. Beer, 43. Bile, 18. Biliousness, 20. Bitters, 46. Bleeding, 49, 52. Blood, 13, 19, 49, 61. Board of Health, 137. Bones, 109. Bowels, 18. Bowlegs, 110. Brain, 88. Brandy, 44. Bread, 24, 38. Breathing, 59, 60, 67. Broken bones, 110. Burning, 61, 118. Butter, 23. C Cake, 24, 29. Candy, 29. Canning fruit, 37, 124. Capillaries, 51, 61. Catching cold, 54, 65, 72, 125, 132. Cells, 8. Cells, blood tubes of, 51. breathing of, 61. burning of, 62. composition of, 11. food of, 13, 55. messages of, 85, 100. Cells of blood, 49, 132. bone, 109. brain, 88. epithelium, 76. muscle, 115. skin, 75. spinal cord, 86. yeast plant, 38. Cheese, 23. Chest, 60. Chewing, 14. Chewing gum, 34. Chewing tobacco, 33. Cider, 42. Cigarettes, 34. Cigars, 34. Clams, 24. Clot, 49. Clothes, 63. Coated tongue, 20. Coffee, 27. Cold, feelings of, 101. Colds, 54, 65, 72, 125, 132. Connective tissue, 9. Contagious diseases, 137. Cooking, 13. Cotton, 63. Cream, 23. Cross-eyes, 102. Cuts, 53. D Deafness, 105. Decay, 124. Delirium tremens, 96. Diaphragm, 60. Digestion, 13. Diphtheria, 53, 134, 137. Dirt, 126. Dirt in eye, 102. Disease germs, 29, 53, 65, 72, 81, 123. Distillation, 43. Drinking cup, 128. E Ear, 104. Ear wax, 104. Eating, 20. Egg, 23. Epidermis, 76. Epithelium, 75. Eustachian tube, 105, 136. Exercise, 118. Eye, 101. Eyeball, 101. Eyelids, 102. F Far sight, 103. Fat, 11, 18, 25, 49, 92. Fear, 92. Feeling, 100. Fermentation, 37. Fever, 125. Fire drill, 93. Fish, 24. Flannel, 63. Flies, 130. Food, 12, 13, 19, 23. Fresh air, 67, 129. Fruit, 25. Fur, 64. G Gastric juice, 17. Gelatine, 11. Germs, 29, 53, 65, 72, 81, 123. Gizzard, 14. Good habits, 94. Grain, 24. H Habit, 94, 127. Hair, 76. Hair dyes, 77. Hair oil, 77. Handkerchief, 135, 136. Healing, 53. Hearing, 104. Heart, 50. Heart beat, 50, 55. Heat, 62, 101. Heating houses, 65. House flies, 129. Hunger, 29. I Intemperance, 29. Intestine, 18. Iron, 12. J Jamaica ginger, 47. Joints, 110. K Kidneys, 62, 78. Knowledge, 89. L Lead, 27. Life, 12. Lime, 12. Linen, 64. Liver, 18, 19. Lungs, 60. M Maggots, 130. Malaria, 130. Matter, 54. Meal, 24. Measles, 134, 137. Meat, 24, 116. Memory, 89. Microbes, 123. Microscope, 8. Milk, 23. Mind, 9, 84, 88. Minerals, 11, 19, 49. Mosquitoes, 130. Motion, 88. Motor nerves, 85. Mouth, 14, 127, 137. Muscles, 115. N Nails, 76. Near sight, 103. Nerve messages, 85. Nerves, 84, 116. Nervousness, 92. Nicotine, 31. Night air, 67. Nose, 127, 135. O Oatmeal, 24. Oysters, 24. P Pain, 100. Pancakes, 24. Pancreatic juice, 18. Pencils, 127, 135. Perspiration, 78. Pie, 29. Pneumonia, 134. Poisons, 19. Potash, 12. Potatoes, 25. Public drinking cup, 128. Pulse, 51. Pus, 54. Q Quarantine, 137. R Red blood cells, 49, 54, 61. Reflex action, 86. Root beer, 43. Round shoulders, 112, 117. Rubbers, 64. S Saliva, 14. Salt, 12, 26. Scarlet fever, 137. Senses, 88, 100. Sensory nerves, 85. Sewers, 81. Sick room, 66. Sight, 101. Skin, 63, 75, 126. Sleep, 90. Slops, 80, 126. Smallpox, 137. Smell, 106. Smoke, 62. Smoking, 34. Snuff, 33. Soda, 12. Spinal cord, 86. Spitting, 32, 127. Sprains, 112. Starch, 11, 14, 18, 25. Steam engine, 62. Stockings, 64. Stomach, 17. Strength, 117. Strong drink, 40. Sugar, 11, 14, 18, 25, 28, 38, 42, 49. Swallowing, 15. Sweat, 63, 78. Sweeping, 129. Sweetbread, 18. T Taste, 28, 106. Tea, 27. Tears, 102. Teeth, 14, 137. Tendon, 115. Thinking, 89. Tight shoes, 112. Tobacco, 31. Tobacco and brain, 98. breathing, 72. chewing, 33. children, 33. digestion, 33. eyes, 104. habit, 34. heart, 57. muscle, 121. strength, 32. taste, 107. teeth, 32. Tongue, 15. Tonsils, 134, 136. Toothpick, 15. Touch, 100. Tuberculosis, 134. Typhoid fever, 53, 127. V Vegetables, 25. Veins, 52. Ventilation, 65, 129. Vinegar, 39. Voice, 68. W Warmth, feeling of, 63. Washing clothes, 80. Waste of body, 75, 78. Water, 10, 19, 26, 49, 127. Wells, 26, 81. Whisky, 44, 71. White blood cells, 49, 53, 132. Whooping cough, 134, 137. Wigglers, 131. Windpipe, 15, 59. Wine, 42. Wool, 63. Words, 68. Working of fruit, 37. Worry, 91. Y Yeast, 24, 38, 42. * * * * * * Transcriber's note: Pg 137 Added period after "223" in "223 Board of health". Pg 141 Replaced a comma with a period after "101" in "Eye, 101". 
47309	----	EXPERIMENTS ON _THE NERVOUS SYSTEM_, WITH OPIUM AND METALLINE SUBSTANCES; MADE CHIEFLY WITH THE VIEW OF DETERMINING THE _NATURE AND EFFECTS_ OF ANIMAL ELECTRICITY. BY ALEXANDER MONRO, M. D. PROFESSOR OF MEDICINE, ANATOMY AND SURGERY IN THE UNIVERSITY OF EDINBURGH; FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS, AND OF THE ROYAL SOCIETY OF EDINBURGH, AND OF THE ROYAL ACADEMY OF SURGERY IN PARIS. EDINBURGH: PRINTED BY ADAM NEILL AND COMPANY, FOR BELL & BRADFUTE, AND T. DUNCAN; AND J. JOHNSON, LONDON. M.DCC.XCIII. CONTENTS. _Page_ INTRODUCTION, 5 Observations on the Circulating and Nervous Systems of Frogs, 6 Experiments with Opium, 9 Corollaries from the above Facts and Experiments, 12 Summary of Experiments made on Animals with Metalline Substances, 17 Summary of Facts proved by the foregoing Experiments, 35 Resemblance of the Fluid put in Motion by the foregoing Experiments to the Electrical Fluid, 38 The Nervous Fluid or Energy not the same with the Electrical, nor with the Fluid put in Motion by the foregoing Experiments, 40 General Conclusions, 42 INTRODUCTION. WHEN, in November last, I began to make Experiments on Animal Electricity, of which I read some account to the Royal Society on the 3d of December; I was not only much hurried with business, but could not procure a sufficient number of Frogs for the purpose. During the last winter and spring, I prosecuted the subject more fully and with greater attention; and, on the third day of June, I read a second paper to the Royal Society, to which I have, since that time, made additions. I shall now state a summary of the chief circumstances I have observed, with a few Remarks. OBSERVATIONS ON THE CIRCULATING AND NERVOUS SYSTEMS OF FROGS. AS my Experiments with Opium, as well as those on Animal Electricity, have been performed on Frogs chiefly; I shall premise some observations on their Circulating and Nervous Systems. THEIR Heart consists of one Auricle and one Ventricle only, their Aorta supplying their Air Vesicles or Lungs, as well as all their other Organs; and, of course, their Venæ Cavæ return the Blood from all parts to the Heart. The Ventricle of their Heart contracts about sixty times in a minute; and the purple colour of the Blood which is seen within it, disappears after each contraction, or the Blood is entirely expelled by its contraction. For upwards of an hour after cutting out its Heart, a Frog can crawl or jump; and, for upwards of half an hour longer, it contracts its Legs when the Toes are hurt, though not with sufficient force to more its Body from the place where it is laid. THEIR Encephalon consists of Brain and Cerebellum, each of which, on its upper part, is divided into two Hemispheres; and, below, they are conjoined by thick Crura, which form the Medulla Oblongata and Spinal Marrow, both of which are proportionally larger than in Man, and more evidently consist of two Cords. There are nine true Vertebræ; and at the sixth of these, the Spinal Marrow terminates in the Cauda Equina. The Sciatic Nerves are formed by three pairs of Nerves, sent out below the seventh, eighth and ninth Vertebræ, and by one pair from the Os Sacrum. A Nerve, resembling our great Sympathetic Nerve, passes downwards from the Abdomen into the Pelvis. TWO days after cutting off the Head of a Frog at its joining with the first Vertebra, I found it sitting with its Legs drawn up, in their usual posture; and when its Toes were hurt, it jumped with very considerable force. Its Heart likewise continued to beat about forty times in a minute, and so strongly as to empty itself and circulate the Blood. IN several Frogs, after cutting off the back part of the six undermost true Vertebræ, I took out all that part of the Spinal Marrow with the Cauda Equina which they cover. The lower Extremities were rendered insensible to common injuries, and lay motionless, yet the Frogs lived several months thereafter, and the wounded parts of their Backs cicatrised; and the Bones of their Legs, which I fractured, were re-united, the Blood circulating freely in their Vessels. IT is universally known, that if, after amputating the Limb of a warm blooded Animal, we repeatedly irritate the Nerves which terminate in Muscles, repeated Convulsions of the Muscles are for some time produced; and that in Frogs, and other cold blooded Animals, the Nerves retain this power still longer. BUT it has been commonly supposed, that, after irritating the Nerve a given number of times, the effect ceases, Authors conceiving that there is lodged in the Nerve some fluid, or other energy which is exhausted by repeated explosions. Instead of this, I have found that the time the Nerves preserve their power is the same, whether we irritate them or not; or that their energy is not exhausted by irritation, unless the irritation be such as sensibly alters their texture. EXPERIMENTS WITH OPIUM. I CUT one hole in the fore and upper part of the Cranium and Dura Mater of a Frog, and another in the back part of the lowermost Vertebræ, and then injected, from the one hole to the other, a small syringe full of water, in five ounces of which one ounce of Opium had been infused for three days. The infusion, by this means brought into contact with the whole surface of the Encephalon and Spinal Marrow, produced almost instantly universal convulsions; and, in less than two minutes thereafter, the Animal was incapable of moving its body from the place where it was laid. A quarter of an hour thereafter, I found the Heart beating twenty-five times only in the minute; and so feebly, that it could not entirely expel the Blood. When, half an hour thereafter, the Sciatic Nerves were pinched, a light tremor only was excited in the Muscles of the Leg; and Animal Electricity produced but feeble twitchings of the Muscles. THE infusion of Opium, injected in the same manner in Rabbits and in a Pig, produced similar effects. I HAD long ago[1] observed, that an infusion of Opium, poured into the Cavity of the Abdomen of a Frog, after cutting out its Heart, occasioned, in a few minutes, convulsions of its hind Legs. I have since found, that, after cutting off the Head, and cutting out the Heart of a Frog, its hind Legs are considerably weakened by pouring an infusion of Opium into the Cavity of its Abdomen. ALTHOUGH an infusion of Opium poured into the Auricle and Ventricle of the Heart of a Frog, instantly renders that Organ incapable of contraction, and, even after the Aorta has been previously cut, occasions convulsions of the Legs, yet I have not found that by Opium applied to the Brain, the Spinal Marrow, the Heart, or Abdominal Viscera, the Muscles of the Legs were so entirely killed as not to perform some motion when their Nerves were pinched, or when they were acted on by Animal Electricity. AFTER taking out the lower half of the Spinal Marrow, and likewise cutting transversely all the parts at the Pelvis, except the Crural Arteries and Veins and Lymphatics, which probably accompany them, I found that an infusion of Opium, applied to the Skin and Muscles of the Legs, affected the superior parts of the Body[2]: more probably, in my opinion, by absorption, than through any minute remanent branches of the Nerves, especially as I do not find, on laying the Vessels so prepared over a gold probe, and touching with it Zinc laid under the Spine, that convulsions of the Legs can be excited. At the same time, the quantity of Opium absorbed is so small, that I could not distinguish its smell or taste in the Blood; nor did I find these distinguishable, in other Experiments, in which the Frogs were violently convulsed after applying the infusion to the surface of their Skin. ANIMAL Electricity or different metals applied to the Head of a Frog, or to any part of its Spine above its sixth Vertebra, do not occasion convulsions of its hind Legs. COROLLARIES FROM THE ABOVE FACTS AND EXPERIMENTS. FROM the above Facts and Experiments, it appears, 1. THAT the Frog, after its Head is cut off, feels pain, and, in consequence of feeling, moves its Body and Limbs. 2. AS the Nerves of the hind Legs are not affected by Animal Electricity, unless it be applied lower than the fifth Vertebra, these Nerves do not seem to be derived solely or chiefly from the Brain or Cerebellum. 3. AS Opium, after the Circulation ceases, affects Organs distant from those to which it is applied, it is beyond doubt, that the latter suffer in consequence of Sympathy of Nerves. 4. IT appears that, in this Animal, there is Sympathy of Nerves after the Head is cut off; or that Sympathy of Nerves does not, in this Animal, depend entirely on the connection of Nerves within the Head. 5. AS, after cutting off the Head, this Animal is susceptible of pain, and, in consequence of that, performs voluntary motion, it appears that, in it, the Brain is not the sole seat of the _Sensorium Commune_. 6. SEVERAL weeks after I had taken out the lowermost half of the Spinal Marrow, and with it the Cauda Equina, I daily applied, for four days running, Animal Electricity to the Sciatic Nerves, by passing a gold Probe between them and the Os Sacrum, and excited several hundreds of convulsions of the Thighs and Legs, and yet found that, on laying bare the Femoral Nerves, and pinching them, the Muscles were slightly convulsed. HENCE, I apprehend, additional force is given to an opinion I ventured many years ago to propose[3], that the Nerves do not receive their energy wholly from the Head and Spinal Marrow, but that the texture of every branch of a Nerve is such as to furnish it, or that the structure of each Nerve is similar to that of the Brain. 7. FROM the above Experiments, it appears probable, in the highest degree, that Opium may be absorbed in such quantity as to produce fatal symptoms. 8. THE following circumstances concur in rendering inadmissible an opinion lately proposed by M. FONTANA, that Poisons operate by changes they produce on the mass of Blood, or on some unknown principle connected with the Blood. a. IF his opinion was just, Poison introduced into a Vein of the extremities, so as to be in contact with this unknown principle, should operate as quickly, and in the same manner as when the Poison is mixed with the Blood near the Heart, which he admits is not the case[4]. b. CUTTING the Spinal Marrow in Frogs, before applying the Poison of the Viper to their Legs, prevents it from killing them[5]; which should not happen, if the Poison acted on the Blood alone. c. HE acknowledges that an Animal bit in its Leg by a Viper, instantaneously feels acute pain[6]; and it, in like manner, feels instantly great uneasiness when the Poison is mixed with its Blood[7]. We know for certain, that, through the medium of the Nerves, we are instantly rendered sensible of injury done to the most distant parts of our Bodies. ARE we not, therefore, in the last mentioned Experiment, to conclude, that the uneasiness was produced because the Poison acted upon the Nerves of the Vessels? d. IN like manner, Animals were convulsed as soon as they were wounded, or received the Poison into a Blood-vessel; and long before the Blood could have reached the Muscles in action[8]. e. AS soon as the distilled Water of Lauro-cerasus was poured into the Stomach of a Pigeon, it was convulsed, died instantly[9], that is, before the Poison could have entered the Mass of Blood. f. MANY years ago, I found, after cutting the Venæ Cavæ and Aorta of a Frog, that a watery solution of Opium poured into the Heart, occasioned, in a few minutes, convulsions in its Legs; and, after cutting out the Heart, that the Opium poured into the Cavity of the Abdomen affected the Legs in like manner; although, in these Experiments, the Circulation was not only interrupted, but the greater part of the Blood evacuated. I THEREFORE then concluded[10], and now conclude, that Opium and other Poisons, even after they are mixed with the Mass of Blood, produce their fatal effects, chiefly and almost solely, by acting on the Nerves of the Heart and Vascular System, and, through these, affecting the whole of the Nervous System. SUMMARY OF EXPERIMENTS MADE ON ANIMALS WITH METALLINE SUBSTANCES. I SHALL now proceed to state the several circumstances I have observed, in my Experiments, which more directly lead us to judge of the Nature and Cause of Animal Electricity. 1. WHEN two Plates of different Metalline Substances, particularly of Zinc and Gold, between which a living Frog is placed, are brought into contact with each other, those Muscles, which are farther from the Brain and Spinal Marrow than the Metals, are convulsed: and this effect follows, although the Animal and Metals are placed on an inverted glass jar, and that a stick of sealing wax is interposed between the hand of the Operator and the Metals; that is, although the Animal, with the Metals, be insulated. I HAVE further observed, that the Metals, disposed as above described, excite convulsions in the Legs, after all the parts of the Frog have been divided transversely at the Pelvis, providing only that they are, thereafter, laid in contact with each other. 2. WHEN all the parts of a living Frog, except the large Nerves called Sciatic, are cut transversely at the Pelvis, and the fore part of the Animal is laid on a plate of Zinc, supported by glass, and the hind Legs on glass; if a gold Probe be applied so as to touch the Zinc and one of the Legs; or a piece of Metal put under one of the Legs; the Muscles of both Legs will be convulsed. THE event is the same, after the Body of the Frog has been cut transversely about the middle of the Spine: or when the Legs are laid on the Zinc and the Spine on Glass. IF a piece of perforated dry Paper is placed between the gold Probe and the Muscles, there will be no convulsions; but wet Paper interposed does not prevent the convulsions. ON separating the gold Probe from the Muscles there are no convulsions. 3. IF, after the Animal and Metals are placed as above described, the joining of the two Legs at the Ossa Pubis is cut, that Leg only will be convulsed with which the gold is in contact. 4. THE Spine of the Frog with the Zinc being placed on one glass, and the Legs on another glass, if the gold, supported by one hand, which we shall call the Right Hand, be applied to the Zinc alone, and not to the Legs, these are not convulsed. But if the Operator applies his left hand to the Legs, or if a bystander, communicating with the Operator by the medium of the floor only, touches them, they are convulsed. If a stick of sealing-wax be interposed between his right hand and the gold, or between his left hand and the Legs; or, if the bystander, touching the Legs, is insulated, by standing on a stool supported by glass feet, the Legs will not be convulsed. If the insulated bystander touches the Legs with one hand, and the Operator with his other hand, the Legs are immediately convulsed. 5. AFTER cutting the Spine transversely under the fifth Vertebra, and all the parts of the Pelvis, except the Sciatic Nerves, and laying the Spine on Zinc supported by glass, and the Legs on glass; if gold be applied to the Zinc, and then to one of the Sciatic Nerves, both Legs, if they have not been separated from each other at the Ossa Pubis, will be convulsed[11]. And this happens although a stick of sealing-wax be interposed between the hand of the Operator and the gold Probe, and although no Metalline Substance touches the Legs. THIS Experiment succeeds after denuding the Sciatic Nerves for the length of an inch, and wiping them dry; and it continues to succeed for an hour or more, and till the Nerves are evidently discoloured and shrunk in their size. And, after that, although we wet the Nerves, their powers are not restored; shewing that the influence had been conveyed not by wetness on the surface of the Nerves, but by the particular matter of which Nerves are composed. THE event is the same, when the upper ends of the Sciatic Nerves are cut away from the Spine, and laid on the Zinc. 6. AFTER preparing the Frog and placing the Metals as in last Experiment, if a piece of thin dry Paper, pierced with a number of small holes, be interposed between the gold Probe and the Sciatic Nerves, the Legs will not be convulsed. But, if the Paper be wetted, although it is not perforated, the Legs will be convulsed. AFTER preparing a Frog, as in last Experiment, and laying the Spine on one glass, and the Legs on another, if the Zinc be laid on a third glass, and the gold Probe applied to it and to the Sciatic Nerves, the Legs will not be convulsed. 8. IF the Spine and hind Legs, connected by the Sciatic Nerves, are all laid on the same plate of Zinc, supported by glass, the Legs are not convulsed on touching the Zinc with the gold Probe held in the right hand, although the left hand is applied to the Legs. 9. IF several Frogs, prepared as above described, are laid upon glass, in a straight line touching each other, and that the first Frog is supported on Zinc, and the last upon Gold; if one end of a brass wire is applied to the Zinc, and the other end of it to the Gold; the Muscles of all the Frogs will be convulsed. The event is the same, although a stick of sealing-wax be interposed between the hand of the Operator and the brass wire: that is, although the Frog with the Metals be insulated. 10. WHEN Frogs are prepared as in last Experiment, and the Spine of the first of them laid on Zinc, and the last supported by the left hand of the Operator, if with a gold Probe, held in his right hand, he touches the Zinc, the Muscles of all the Frogs will be convulsed. But if the hind Legs, as well as the Spine, of the first Frog be laid on the Zinc, the Muscles of that Frog will not be convulsed. 11. AFTER a Frog was prepared as before described, I cut the Sciatic Nerves where they are about to enter the Thighs, and laid their cut ends in contact with the Muscles, and then touched the Zinc and Nerves with a gold Probe, without exciting convulsions in the Thighs or Legs. 12. AFTER cutting the Sciatic Nerves, I tied together their divided parts, and then touched the Zinc and Nerves above the Ligature, with the Gold, without finding that the Legs were convulsed, when the Zinc supporting the Spine was laid on one glass and the Legs on another: but when the Metals and parts of the Frog were laid on a wet Table, the Muscles of the Leg were convulsed. 13. WHEN the Sciatic Nerves have been cut and rejoined by Ligature, if while the Gold is, with one hand, applied to the Zinc and Nerves, above the Ligature, the other hand touches the Feet, the Legs are convulsed. 14. IF the two hind Legs of a Frog are separated from each other, and their Sciatic Nerves afterwards tied to each other; if one of the Legs be laid on Zinc supported by glass, and the other Leg on glass, when, with one hand, the Toes of one of the Legs are touched, whilst with the other hand a gold Probe is applied to the Zinc and Nerve of the Leg which it supports, this Leg only will be convulsed. But if the gold Probe touching the Zinc be applied to the Nerve of the most distant Leg, both Legs will be convulsed. 15. I FOUND it was not necessary, in order to excite convulsions, that either of the Metals should be in contact with the living Nerve or living Flesh of the Frog; for if, after separating from each other the hind Legs of a Frog, and cutting transversely the upper part of their Sciatic Nerves, I laid a piece of putrid or boiled beef between their Sciatic Nerves, and two other pieces of putrid or boiled beef between their Toes and a plate of Zinc; if, with the point of a gold Probe, the side of which was applied to the piece of beef placed between the Sciatic Nerves, I touched the Zinc, both Legs were convulsed. 16. IN like manner, when I placed alternately, in a straight line, a number of dead and living Frogs touching each other, and in the living Frogs cut, at their Pelvis, all the parts but the Sciatic Nerves; if, with my left hand I touched a dead Frog at one end of the line, and with a gold Probe, held in my right hand, I touched a plate of Zinc, on which a dead Frog was laid at the other end of the line or chain of Frogs, the Muscles of all the living Frogs were convulsed. 17. WHEN a chain of living and dead Frogs was formed, as in the two last Experiments, but without cutting at their Pelvis all the parts but the Nerves; on applying the gold to the Zinc, convulsions of the Muscles were not excited. 18. IT has been found, that, if a plate of Zinc is applied to the upper part of the point of the Tongue, and a plate of Silver to its under part, on bringing the two Metals into contact with each other, a pungent disagreeable feeling, which it is difficult to describe, is produced in the point of the Tongue. And if a plate of Zinc is placed between the upper lip and the gums, and a plate of gold applied to the upper or under part of the Tongue, on bringing these two Metals into contact with each other, the person imagines that he sees a flash of lightning, which, however, a bystander in a dark room does not perceive; and the person performing the Experiment perceives the flash, though he is hoodwinked. IT has been alleged, that the Flash happens before the two Metals touch each other, and is repeated on separating them; but these facts appear to me very doubtful, as I do not find that a Flash is produced when a piece of Cambric-paper, in which a number of holes is pierced with a pin, is interposed between the Zinc and Silver, although the Paper does not in thickness exceed 1/1500 part of an inch. AFTER performing this Experiment repeatedly, I constantly felt a pain in my upper jaw at the place to which the Zinc had been applied, which continued for an hour or more: And in one Experiment after I had applied a blunt Probe of Zinc to the Septum Narium, and repeatedly touched with it a Crown piece of Silver applied to the Tongue, and thereby produced the appearance of a Flash, several drops of Blood fell from that Nostril; and Dr FOWLER, after making such an Experiment on his Ears, observed a similar effect[12]. I HAVE farther observed, that although the previous application of a second plate of Silver to one half of the plate of Zinc, does not prevent the Flash when the other half of the plate of Zinc, touching the Tongue, is brought into contact with the first piece of Silver placed between the lip and the gum; yet if the Zinc and Silver are in the first place applied to each other, then placed between the lip and gum, and, after this, touched with the Tongue, there is no appearance of a Flash, although some degree of pungency and a disagreeable sensation is perceived by the Tongue: and a mixed mass, composed of one part of Zinc and two parts of Quicksilver, or a mass composed of three parts of Zinc and one of Silver, incorporated in a furnace, have not the effect, when they are applied to Nerves, of exciting convulsions of the Muscles in which the Nerves terminate. I HAVE also found, that two thick pieces of raw or boiled flesh, one between the Zinc and Tongue, and the other between the Silver and Tongue, do not prevent the disagreeable pungent sensation when the two Metals touch: and, in like manner, that the interpolation of two pieces of flesh between the Zinc and Tongue, and between the Silver and the upper Lip, does not prevent the appearance of a flash, on bringing the two Metals into contact. 19. I PUT a very thick plate of Zinc into a vessel with water, and placed, near to it, in the water, the under part of the Spine and the hind Legs of a Frog, after cutting all the parts at the Pelvis except the Sciatic Nerves. I then touched the Zinc with a gold Probe, and found, that, when I touched that part of the Zinc which was above the water, the Legs of the Frog were not affected; but when I touched that part of the Zinc which was below the surface of the water, the Legs of the Frog were convulsed[13]. I NEXT put into the water one of the hind Legs of a dead Frog, and its other Leg into an adjoining vessel with water. Into the opposite side of the second vessel, I put one of the hind Legs of a living Frog, in which all the parts at the Pelvis, except the Sciatic Nerves, were cut; and into a third glass vessel with water, I put its other Leg. When I now touched that part of the Zinc, which was below the surface of the water with a gold Probe, the Legs were not convulsed; but, if I, at the same time, dipped the finger of my other hand into the water contained in the third vessel, they were convulsed: when, instead of my finger, I dipped into the water a stick of sealing-wax, held in my other hand, the Legs were not convulsed. I FOUND, by the three following Experiments, that the Muscles are convulsed, whether the Influence, produced by the application of the Metals, passes upwards or downwards along the Nerves. 20. I CUT four living Frogs transversely at the middle part of their Spines, and threw away the fore parts of their Bodies and their Abdominal Viscera. I NEXT cut, at their _Pelves_ all the Parts but the Sciatic Nerves; and at their Knees, I cut all the Parts but the Crural Nerves; and, in all of them, I cut asunder the joining of the two hind Legs at their Ossa Pubis. I then laid the Legs of all of them in a straight line, supported on different Glass Vessels inverted, in such a manner that the Foot of one Frog touched the Foot of the next to it. HAVING then placed a Plate of Zinc under the Foot of the first Frog, and holding in my left hand the Foot of the fourth or last Frog, I touched the Zinc with a gold Probe which I held in my right hand; and found that all the Muscles of the Loins, Thighs and Legs of the four Frogs were convulsed. 21. WHEN I placed the two Frogs in the middle, with their Spines contiguous to each other, and the Feet of both touching the Spines of the other two Frogs forming the Extremities of the Chain, and of course the Feet of one of these resting on the Zinc, and the Feet of the other supported by my left hand: On touching the Zinc with the gold Probe held in my right hand, all the Muscles of the Frogs were, as before, convulsed. 22. WHEN I now turned aside the right Legs of all the Frogs, so that they did not form a Chain by touching the next Frogs; the right Legs were not convulsed. IT is evident, that in whatever direction we suppose the influence to have passed in its Circle, it must, in Experiment 20th, have passed up one Leg and down the other in the same Frog: And, in Experiment 21st, if it passed from one end of the Chain to the other end of it, it must have passed upwards in two of the Frogs, and downwards in the other two; or if the influence passed from the two ends of the Chain towards its middle, where the Spines of the two middlemost Frogs were contiguous, it must have passed upwards in all of them. 23. WHEN after cutting four living Frogs transversely at the middle of their Spines, but without cutting at their Pelves all the Parts but the Sciatic Nerves, I placed the hind Parts of them in a Chain, as in Experiments 20th, 21st and 22d, the Muscles were not convulsed on applying the Gold to the Zinc. I NEXT found, that after placing in contact with each other the several Muscles which had been cut transversely in Experiments 20th, 21st and 22d, allowing the Nerves to remain undivided, the muscles were not convulsed when I touched the Plate of Zinc with the gold Probe held in my right hand, although I touched the other end of the Chain of Frogs with my left hand. THE reason why the Muscles were convulsed in Experiments 20th, 21st and 22d, and not in Experiment 23d, evidently is, that in the former, the influence was concentrated in the Nerve, in the latter the influence was diffused; that is, was in part conveyed by other Organs, as well as by the Trunks of the Nerves. 24. AFTER finding that I could readily excite Convulsions in the hind Legs of a Frog, without cutting it, by laying its Back on a Plate of Zinc, and introducing a gold Probe within its Intestinum Rectum and touching the Zinc with the side of the Probe, I produced two or three hundred Convulsions, succeeding each other quickly, and observed that its Legs were, by these means, so much weakened, that it could not jump, and crawled with difficulty, but in a few minutes it recovered nearly the full force of its Muscles. IN other Frogs I passed a gold Wire between their Sciatic Nerves and Os Sacrum, and twisted together the two ends of the Wire over the Backs of the Animals. I then put them into a Zinc Vessel filled with Water, or into a Glass Vessel filled with Water, in the bottom of which I laid a large Plate of Zinc: So that every time the Animals by moving separated the Gold from the Zinc, and again brought them into contact, their hind Legs were convulsed. I allowed them to remain three or four days in this situation, and found that their Limbs were weakened considerably, but not exhausted of their Power of Motion; and, after removing the gold Wire, the Limbs by degrees recovered their strength. I MADE the same Experiment on those Frogs in which I had, six weeks before, cut out, from behind, all that part of their Spinal Marrow which is covered by the six undermost Vertebræ, and found, several days after the Frogs had been subjected to the Experiment, that, by pinching their Sciatic and Femoral Nerves, and still more readily by the application of the Gold and Zinc, weak convulsions of the Muscles were excited. 25. AFTER Frogs were prepared as above described, by cutting their Spines transversely, and then all the parts of their Pelves, except their Sciatic Nerves, I found that slight Electrical Shocks, or a Leyden Phial discharged directly through the Limbs of a Frog, or indirectly by the medium of water, produced convulsions in their Muscles, exactly resembling those excited by the Metals. And when, after moderate Electrical Shocks had been passed repeatedly through their Legs, the Metals were applied to their Nerves, in the manner before mentioned, the Muscles were convulsed. I found, likewise, that after cutting the Nerves transversely, and tying them together, Electrical Shocks were conducted by the Nerves, and occasioned convulsions of the Muscles. WHEN I had killed Frogs, by discharging through them, from their foreheads to their hind feet, large Leyden Phials highly charged, I found their Nerves or Muscles, or both, so much deranged, that feeble convulsions only could be excited by pinching the Nerves, or by applying the Metals to them. SUMMARY OF FACTS PROVED BY THE FOREGOING EXPERIMENTS. ON reviewing the foregoing Experiments, we shall find the following Facts fully proved. 1. ON forming a Circle by means of the parts of a living Animal and of two different metallic Bodies, especially Gold and Zinc, in contact with each other, if a Nerve makes part of the Circle, the Muscles in which the Nerve terminates are convulsed. 2. ALTHOUGH the Nerve making part of such a Circle has been cut transversely, yet, if the divided parts of the Nerve are laid in contact with each other, or tied together, the Muscles, in which it naturally terminates, are convulsed. 3. IF the Metals, composing parts of the Circle, are kept steadily in contact with each other, the convulsions of the Muscles cease. But, if they are separated from each other and again rejoined, the convulsions are repeated. 4. THE effects are the same, although the dead parts of an Animal or pure water make parts of the Circle. 5. ALTHOUGH the dead parts of an Animal, making part of such a Circle, are in contact with the Metals, the effects are the same. 6. A MUSCLE making part of such a Circle may be convulsed whilst the matter put in motion is passing in the direction from the Muscle to the Nerve. 7. THE Muscle may be convulsed although it makes no part of the Circle in which the matter put in motion passes, as appears from comparing Experiment 5th with Experiments 13th and 14th. From Experiment 13th, it appears, that the Fluid put in Motion by the Metals passes readily along a Nerve, after it has been cut, providing the divided Parts of it are brought into contact with each other. Yet in Experiment 14th, in which the left hand of the Operator was not applied to the Foot of the Frog, the Muscles in which the Nerve, lower than the Ligature, terminated, were not convulsed, because the Fluid put in motion did not descend lower than the place at which the gold Probe touched the Nerve above the Ligature. We may therefore presume that when a Nerve which has not been cut, as in Experiment 5th, is touched with the gold Probe, the Fluid put in motion does not pass lower in the Nerve than the place of the Probe. Hence we perceive the error of those who suppose that the moisture on the surface of the Nerve conduces the Fluid put in motion to the Muscles, and that their action is in consequence of the direct operation of this Fluid upon their Fibres. 8. THE effects are the same when the Animal and the Metals are insulated, by being placed on Glass, whilst Sealing-wax is interposed between the hand of the Operator and the Metals. 9. IF any part of the Circle is composed of Sealing-wax or Glass, the Muscles are not convulsed. 10. CONVULSIONS are not excited unless the Metals are in contact with each other; and unless both Metals are also in contact with the Animal Substances or the Water making part of the Circle. RESEMBLANCE OF THE FLUID PUT IN MOTION BY THE FOREGOING EXPERIMENTS TO THE ELECTRICAL FLUID. THE Fluid set in motion by the application of the Metals to each other, and to Animal Bodies or to Water, agrees with or resembles the Electrical Fluid in the following respects. LIKE the Electrical Fluid, it communicates the sense of pungency to the Tongue. LIKE the Electrical Fluid, it is conveyed readily by Water, Blood, the Bodies of Animals, the Metals; and is arrested in its course by Glass, Sealing-Wax, _&c._ IT passes, with similar rapidity, through the Bodies of Animals. LIKE the Electrical Fluid, it excites the activity of the Vessels of a living Animal, as the Pain it gives and Hemorrhagy it produces seem to prove. Hence perhaps it might be employed with advantage in Amenorrhoea. IT excites Convulsions of the Muscles in the same manner, and with the same effects as Electricity. WHEN the Metals and Animal are kept steadily in contact with each other, the Convulsions cease, or an Equilibrium seems to be produced, as after discharging a Leyden Phial. THE NERVOUS FLUID OR ENERGY NOT THE SAME WITH THE ELECTRICAL NOR WITH THE FLUID PUT IN MOTION BY THE FOREGOING EXPERIMENTS. THAT the Nervous Fluid is the same with the Electrical, or with the Fluid which is put in motion by the foregoing Experiments, is, I apprehend, disproved by the following circumstances. 1. WITHOUT stating the difficulty there is in conceiving how the Electrical Fluid can be accumulated by or confined within our Nervous System, we may observe that where the Electrical Fluid, or Fluid resembling that put in motion by the foregoing Experiments, is accumulated by an Animal, such as the Torpedo or Gymnotus, a proper apparatus is given to the Animal, by means of which it is enabled to collect and to discharge this Fluid. 2. THE Nervous Power is excited by chemical or by mechanical Stimuli; and, on the other hand, is destroyed by Opium and other Poisons, which cannot be imagined to act on the Electrical Fluid. 3. I HAVE, I apprehend, refuted the theory of Doctors GALVANI, VALLI and others, which supposes that the Nerve is electrified _plus_ and the Muscle _minus_, resembling the Leyden Phial, by shewing that the Muscles are convulsed where there is no communication between them and the Metals, but by the medium of the Nerve; or when the Metals are applied to different parts of the Nerve alone, without touching the Muscles which are convulsed, and when the Muscle which is convulsed makes no part of the Circle in which the Matter that is put in motion passes. 4. I HAVE proved, that the Muscles are convulsed whilst the current of the Electrical Matter is passing from them and from the smaller Branches of the Nerves into their Trunks; and as a Muscle is never thrown into Action by the Nervous Energy, except when this passes from the Trunk of the Nerve into its Branches, and from these into the Muscle, it appears that when, in these Experiments, the Muscles were convulsed, the Nervous and the Electrical Fluids were moving in opposite Directions; from which we may infer, that, in their Nature, they differ essentially from each other. 5. THE Nervous Energy is stopped by a tight Ligature or by the transverse Incision of a Nerve, although its divided Parts are thereafter placed in contact with each other; whereas the Electrical Fluid or the Fluid excited by the Metals, passes readily, downwards or upwards, along a Nerve which has been tied or cut. 6. AFTER the Limb of a living Animal has been amputated, frequent Convulsions of the same Muscles may be excited by applying Mechanical or Chemical Stimuli to its Nerves; whereas Electrical Matter discharges itself suddenly. HENCE I conclude, 1. THAT the Fluid, which, on the application of Metalline Bodies to Animals, occasions Convulsions of their Muscles, is electrical, or resembles greatly the Electrical Fluid. 2. THAT this Fluid does not operate directly on the Muscular Fibres, but merely by the Medium of their Nerves. 3. THAT this Fluid and the Nervous Fluid or Energy are not the same, but differ essentially in their Nature. 4. THAT this Fluid acts merely as a Stimulus to the Nervous Fluid or Energy. 5. THAT these Experiments have merely shown a new mode of exciting the Nervous Fluid or Energy, without throwing any farther or direct Light on the nature of this Fluid or Energy. FINIS. FOOTNOTES: [1] See Edin. Phys. Ess. Vol. III. [2] See Edin. Phys. Ess. Vol. III. [3] See Observations on the Nervous System, 1783, Chap. x. and xi. [4] See FONTANA sur les Poisons, 1781, p. 267. [5] See FONTANA, p. 293. [6] FONTANA, p. 244. [7] FONTANA, p. 259. [8] FONTANA, p. 112. p. 259. [9] FONTANA, p. 142. [10] Edin. Phys. Ess. published in 1771, p. 363. [11] Very small portions of different metals, applied as above described, have astonishing effects; and although I have found that large portions of the metals produced convulsions, when smaller had failed, or that they produced stronger convulsions; yet the effects are by no means proportioned to the weight of the metals employed, nor to the extent of their surfaces which are suddenly brought into contact. In most of my Experiments, I employed a plate of Zinc, about five inches long, three inches broad, and about one-third of an inch thick; and a gold Probe, somewhat thicker and longer than the Probes Surgeons commonly use. [12] See Dr FOWLER'S Book, p. 85. [13] After reading to the Royal Society, on the 3d of June, an account of this Experiment, which I had made in the beginning of May, I found, from an ingenious publication of my Pupil Dr FOWLER, which I received that evening, that the same Experiment had been performed by him. TRANSCRIBER'S NOTE: --Obvious print and punctuation errors were corrected. 
31616	----	[Illustration: Book Cover] HEALTH LESSONS BOOK I BY ALVIN DAVISON, M.S., A.M., PH.D. PROFESSOR OF BIOLOGY IN LAFAYETTE COLLEGE [Illustration: Publisher Symbol] NEW YORK · CINCINNATI · CHICAGO AMERICAN BOOK COMPANY COPYRIGHT, 1910, BY ALVIN DAVISON. ENTERED AT STATIONERS' HALL, LONDON. HEALTH LESSONS. BK. 1. W. P. 6 [Illustration: Exercise, clean air, and well-chewed food make a strong and healthy body.] PREFACE Scarcely one half of the children of our country continue in school much beyond the fifth grade. It is important, therefore, that so far as possible the knowledge which has most to do with human welfare should be presented in the early years of school life. Fisher, Metchnikoff, Sedgwick, and others have shown that the health of a people influences the prosperity and happiness of a nation more than any other one thing. The highest patriotism is therefore the conservation of health. The seven hundred thousand lives annually destroyed by infectious diseases and the million other serious cases of sickness from contagious maladies, with all their attendant suffering, are largely sacrifices on the altar of ignorance. The loving mother menaces the life of her babe by feeding it milk with a germ content nearly half as great as that of sewage, the anemic girl sleeps with fast-closed windows, wondering in the morning why she feels so lifeless, and the one-time vigorous boy goes to a consumptive's early grave, because they did not know (what every school ought to teach) the way to health. Doctor Price, the Secretary of the State Board of Health of Maryland, recently said before the American Public Health Association that the text-books of our schools show a marked disregard for the urgent problems which enter our daily life, such as the prevention of tuberculosis, typhoid fever, and acute infectious diseases. Since the observing public have seen educated communities decrease their death rate from typhoid fever, tuberculosis, and diphtheria from one third to three fourths by heeding the health call, lawmakers are becoming convinced that the needless waste of human life should be stopped. Michigan has already decreed that every school child shall be taught the cause and prevention of the communicable diseases, and several other states are contemplating like action. This book meets fully the demands of all such laws as are contemplated, and presents the important truths not by dogmatic assertion, but by citing specific facts appealing to the child mind in such a way as to make a lasting impression. After the eleventh year of age, the first cause of death among school children is tuberculosis. The chief aim of the author has been to show the child the sure way of preventing this disease and others of like nature, and to establish an undying faith in the motto of Pasteur, "It is within the power of man to rid himself of every parasitic disease." Nearly all of the illustrations used are from photographs and drawings specially prepared for this book. These, together with the large amount of material gleaned from original sources and from the author's experiments in the laboratory, will, it is hoped, make this little volume worthy of the same generous welcome accorded the two earlier books of this series. CONTENTS CHAPTER PAGE I. CARING FOR THE HEALTH 9 II. PARTS OF THE BODY 15 III. FEEDING THE BODY 21 IV. FOOD AND HEALTH 30 V. HOW PLANTS SOUR OR SPOIL FOOD 36 VI. MILK MAY BE A FOOD OR A POISON 41 VII. HOW THE BODY USES FOOD 47 VIII. THE CARE OF THE MOUTH 60 IX. ALCOHOLIC DRINKS 68 X. ALCOHOL AND HEALTH 74 XI. TOBACCO AND THE DRUGS WHICH INJURE THE HEALTH 78 XII. THE SKIN AND BATHING 85 XIII. CLOTHING AND HOW TO USE IT 94 XIV. BREATHING 100 XV. FRESH AIR AND HEALTH 111 XVI. THE BLOOD AND HOW IT FLOWS THROUGH THE BODY 117 XVII. INSECTS AND HEALTH 127 XVIII. HOW THE BODY MOVES 135 XIX. THE MUSCLES AND HEALTH 144 XX. HOW THE BODY IS GOVERNED 149 XXI. HOW NARCOTICS AND STIMULANTS AFFECT THE BRAIN AND NERVES 158 XXII. THE SENSES, OR DOORS OF KNOWLEDGE 165 XXIII. KEEPING AWAY SICKNESS 174 XXIV. HELPING BEFORE THE DOCTOR COMES 183 INDEX 189 HEALTH LESSONS CHAPTER I CARING FOR THE HEALTH =Good Health better than Gold.=--Horses and houses, balls and dolls, and much else that people think they want to make them happy can be bought with money. The one thing which is worth more than all else cannot be bought with even a houseful of gold. This thing is good health. Over three million persons in our country are now sick, and many of them are suffering much pain. Some of them would give all the money they have to gain once more the good health which the poorest may usually enjoy by right living day by day. =How long shall you live?=--In this country most of the persons born live to be over forty years of age, and some live more than one hundred years. A hundred years ago most persons died before the age of thirty-five years. In London three hundred years ago only about one half of those born reached the age of twenty-five years. Scarcely one half of the people in India to-day live beyond the age of twenty-five years. In fact, people in India are dying nearly twice as fast as in our own country. This is because they have not learned how to take care of the body in India so well as we have. [Illustration: FIG. 1.--By right living this woman remained in good health for several years after she was a century old.] The study which tells how to keep well is _Hygiene_. Whether you keep well and live long, or suffer much from headaches, cold, and other sickness, depends largely on how you care for your body. =Working together for Health.=--One cannot always keep well and strong by his own efforts. The grocer and milkman may sell to you bad food, the town may furnish impure water, churches and schools may injure your health by failing to supply fresh air in their buildings. More than a hundred thousand people were made very sick last year through the use of water poisoned by waste matter which other persons carelessly let reach the streams and wells. Many of the sick died of the fever caused by this water. Although it cannot be said that we are engaged in real war, yet we are surely killing one another by our thoughtless habits in scattering disease. We must therefore not only know how to care for our own bodies, but teach all to help one another to keep well. =A Lesson from War.=--The mention of war makes those who know its terrors shudder. Disease has caused more than ten times as much suffering and death as war with its harvest of mangled bodies, shattered limbs, and blinded eyes. In our four months' war with Spain in 1898 only 268 soldiers were killed in battle, while nearly 4000 brave men died from disease. We lost more than ten men by disease to every one killed by bullets. In the late war between Japan and Russia the Japanese soldiers cared for their health so carefully that only one fourth as many died from disease as perished in battle. This shows that with care for the health the small men of Japan saved themselves from disease, and thus won a victory told around the world. [Illustration: FIG. 2.--The Surgeon General who, by keeping the soldiers well, helped Japan win in the war against Russia.] =The Battle with Disease.=--For long ages sickness has caused more sorrow, misery, and death than famine, war, and wild beasts. Many years ago a plague called the _black death_ swept over most of the earth, and killed nearly one third of the inhabitants. A little more than a hundred years ago yellow fever killed thousands of people in Philadelphia and New York in a few weeks. When Boston was a city with a population of 11,000, more than one half of the persons had smallpox in one year. Within a few years one half of the sturdy red men of our forests were slain by smallpox when it first visited our shores. Before the year 1798 few boys or girls reached the age of twenty years without a pit-marked face due to the dreadful disease of smallpox. This disease was formerly more common than measles and chicken pox now are because we had not yet learned how to prevent it as we do to-day. =Victory over Disease.=--Cholera, yellow fever, black death, and smallpox no longer cause people to flee into the wilderness to escape them when they occasionally break out in a town or city. We have learned how to prevent these ailments among people who will obey the laws of health. [Illustration: FIG. 3.--One of the thousands of sturdy red men which smallpox slew before we learned how to prevent the disease.] Until the year 1900, people fled from a city when yellow fever was announced, but now any one can sleep with a fever patient and not catch the disease, because we have learned how to prevent it. Nurses and doctors no longer hesitate to sit for hours in the rooms of those sick with smallpox because they know how to treat the body to keep away this disease. By studying this book, boys and girls may learn not only how to keep free from these diseases, but how to manage their bodies to make them strong enough to escape other diseases. =As the Twig is bent so the Tree is inclined.=--This old saying means that a strong, straight, healthy, full-grown tree cannot come from a weak and bent young tree. Health in manhood and womanhood depends on how the health is cared for in childhood. The foundation for disease is often laid during school years. The making of strong bodies that will live joyous lives for long years must begin in boyhood and girlhood. In youth is the time to begin right living. Bad habits formed in early life often cause much sorrow in later years. It is said that over one half the drunkards began drinking liquor before they were twenty years of age and most of the smokers began to use tobacco before they were twenty years old. PRACTICAL QUESTIONS 1. What is worth most in this world? 2. How many people are sick in our country? 3. How long do most people live? 4. Why do people not live long in India? 5. What is hygiene? 6. How many more deaths are caused by disease than by war? 7. Give some facts about smallpox. 8. Why do we have no fear of yellow fever and smallpox now? 9. Why should you be careful of your health while young? 10. When do most smokers and drinkers begin their bad habits? CHAPTER II PARTS OF THE BODY =Regions of the Body.=--In order to talk about any part of the body it must have a name. The main portion of the body is called the _trunk_. At the top of the trunk is the _head_. The arms and legs are known as _limbs_ or _extremities_. The part of the arm between the elbow and wrist is the _forearm_. The _thigh_ is the part of the leg between the knee and hip. The upper part of the trunk is called the _chest_ and is encircled by the ribs. The lower part of the trunk is named the _abdomen_. A large cavity within the chest contains the lungs and heart. The cavity of the abdomen is filled with the liver, stomach, food tube, and other working parts. =The Plan of the Body.=--All parts of the body are not the same. One part has one kind of work to do while another performs quite a different duty. The covering of the body is the _skin_. Beneath is the red meat called _muscle_. It looks just like the beef bought at the butcher shop which is the muscle of a cow or ox. Nearly one half of the weight of the body is made of muscle. [Illustration: FIG. 4.--General plan of the organs of the body.] The muscle is fastened to the _bones_ which support the body and give it stiffness. The muscle by pulling on the bones helps the body to do all kinds of work. The muscles and bones cannot work day after day without being fed. For this reason a food tube leads from the mouth down into the trunk to prepare milk, meat, bread, or other food, for the use of the body. =Feeding the Body.=--The mouth receives the food and chews it so that it may be easily swallowed. It then goes into a sac called the _stomach_. Here the hard parts are broken up into tiny bits and float about in a watery fluid. This goes out of the stomach into a long crooked tube, the _intestine_. Here the particles are made still finer, and the whole mass is then ready to be carried to every part of the muscles, bones, and brain to build up what is being worn out in work and play. =Carrying Food through the Body.=--In all parts of the body are little branching tubes. These unite into larger tubes leading to the heart. Through these tubes flows _blood_. Hundreds of tiny tubes in the walls of the intestine drink in the watery food, and it flows with the blood to the heart. The heart then pushes this blood with its food out through another set of tubes which divide into fine branches as they lead to every part of the body (Fig. 5). =Getting rid of Ashes and Worn-out Parts.=--The body works like a machine. Food is used somewhat as a locomotive uses coal to give it power to work. Some ashes are left from the used food, and other waste matter is formed by the dead and worn-out parts of the body. This waste is gathered up by the richly branching blood tubes and carried to the lungs. Here some of it passes out at every breath. Part of the waste goes out through the skin with the sweat and part passes out through the kidneys. In this way the dead matter is kept from collecting in the body and clogging its parts. =How the Parts of the Body are made to work Together.=--The mass of red flesh covering the bones is made up of many pieces called muscles. Whenever we catch a ball or run or even speak, more than a dozen muscles must be made to act together just in the right way. When food goes into the stomach, something must tell the juice to flow out of the walls to act on the food. The boss or manager of all the work carried on by the thousands of parts of the body is known as the _brain_ and _spinal cord_ with their tiny threads, the _nerves_, spreading everywhere through bones and muscles. The brain and spinal cord give the orders and the nerves carry them (Fig. 5). =The Servants of the Body.=--The parts of the body are much like the servants in a large house or the clerks in a store. One servant or clerk does one kind of work while another does something entirely different. Each portion of the body does a different kind of work. Each one of these parts doing a particular work is called an _organ_. The stomach is an organ to prepare food and the heart is an organ for sending the blood through the body. [Illustration: FIG. 5.--On the left are shown the branching tubes which carry blood to all parts of the body; on the right are the brain, spinal cord, and nerves which direct the work of the organs.] The entire body is composed of several hundred organs. Each of them is formed of several kinds of materials named _tissue_. A skinlike tissue makes up the lining of the stomach, while its outside is made of muscular tissue. The smallest parts of a tissue are little bodies named _cells_, and very fine threads called _fibers_. =Growth of the Body.=--The body grows rapidly in childhood and more slowly after the sixteenth year, but it continues to get larger until about the twenty-fifth year of age. Some children always grow slowly, have weak bones, and frail bodies. This is generally so because they have poor food or do not chew it well, and get too little fresh air, sunshine, and sleep. The use of beer, wine, or tobacco may hinder the body from using food for growth, or they may poison the body so that it will never be large and strong. The body should grow about a hundred pounds in weight during the first thirteen years of life. Whether children grow little or much generally depends on the food they give their bodies. PRACTICAL QUESTIONS 1. Point out and name four parts of the body. 2. Name the two parts of the trunk. 3. What does the chest contain? 4. What is muscle? 5. How is the body fed? 6. Give three parts taking waste out of the body. 7. Of what use are the brain and nerves? 8. Name two organs. 9. How long does the body continue to grow? 10. Why are some children weak and of slow growth? CHAPTER III FEEDING THE BODY [Illustration: FIG. 6.--Photograph of the outer dead skin pushed off from a black snake crawling through the brush.] =Why the Body needs Food.=--Every living thing, whether a plant or an animal, needs food. While the whole body lives, a part of it is constantly dying. The entire outer layer of a snake's skin dies three or four times during a year and is cast off, sometimes in a single piece. We can scrape dead bits of skin from the surface of our body at any time. Tiny particles are dying in all regions of the body, and we should soon waste away if food were not taken to make up the loss for the worn-out parts. The body also needs food to help it do its work and keep warm. The body has the strange power of using food eaten to make the legs and arms move and the brain to think. In doing this the body is said to burn the food. =How the Body burns itself and also Food.=--If a boy is weighed just before playing a game of ball and again afterward, he will find that part of his body has been used up and given off in the breath and sweat. He has burned part of his body, and the breath and sweat are like the smoke given off when a match is burned. One fifth of the air is made of a gas called _oxygen_. When anything becomes very hot, this oxygen makes it burst into a flame and burn. We breathe in oxygen with the air and the living action of the body causes such a slow union of the oxygen and the tissues that there is no blaze although there is a little heat. =Kinds of Food.=--There are four general classes of foods. These are the _building foods_, the _sugars_ and _starches_, the _fats_, and the _mineral foods_. The building foods are those which help largely in forming new muscle and blood or other parts of the body. _Proteids_ is another name for building foods. _Sugars_ and _starches_ are placed in one group because starch changes to sugar within the body. If you chew a starchy food like bread for a few minutes, it will begin to taste sweet because the starch is becoming sugar. Fats are got not only from fat meat but also from eggs, butter, milk, and many other foods. There is some mineral matter, such as potash and soda, in many of the vegetables and meats eaten, and we use much table salt to season other foods. [Illustration: FIG. 7.--Good foods for building muscles, blood, and bone.] =Body-building Foods.=--A person with all the sugar, molasses, starch, butter, and lard he could eat would starve to death in a few weeks because none of these foods would help to build up the dying parts of the body. A large amount of body builder is found in lean meat, eggs, milk, peas, beans, corn meal, and bread. Bread and milk is a good food to make the body grow. If the body takes in more building food than it needs for repairs, it may store it up in the form of fat or burn it to help the body do its work. =The Fuel Foods.=--The fuel foods are the sugars, starches, and fats. These are the foods which the body can easily burn to keep it warm and give it power to act. Candy, molasses, or sugar in any form, taken in small quantities, is a good food. Starch, which the body quickly changes to sugar, is a much cheaper food. Meats contain very little starch, but nearly all vegetables contain much starch. Three fourths of corn meal, rice, wheat flour, and soda crackers consists of starch. More than one half of white bread, dried beans, and peas is made of pure starch, and there is much starch in potatoes. _Fat_ is more abundant in animal than in vegetable food. Castor oil and cotton-seed oil are fats from vegetables. The fat of the cow is called _suet_ or _tallow_, while the fat of the hog is known as _lard_. _Butter_ is the fat collected from milk. Cream and eggs contain much fat. When persons eat too much of the sugars, starches, or fats, the body may store them up as fat. For this reason thin persons wishing to gain in flesh eat eggs, nuts, and rich milk. =The Mineral Foods.=--The body must have not only lime to help form the bones, but iron, salt, soda, and potash for other parts of the body. All these minerals except salt are found in many of the common foods. [Illustration: FIG. 8.--Good foods for giving the body power and heat.] Water is one of the most important of the mineral foods because it helps the body use all the other foods. Most people drink too little water to enjoy the best health. The body needs more than two quarts of water every day. There is much water in our foods. More than one half of eggs, meat, and potatoes is made of water, and more than three fourths of tomatoes, green corn, onions, cabbage, and string beans is composed of water. We should drink one quart or more of water daily. It should not be used ice cold, and very little should be taken at meal time. [Illustration: FIG. 9.--Diagram showing how the drainage from a house with a sick person caused one hundred and twenty cases of typhoid fever at Mount Savage, Maryland.] =Water and Health.=--One of the common causes of sickness is bad water. Water from shallow wells within a hundred feet of barnyards, pigpens, or other outhouses is usually unsafe to drink. At Newport, Rhode Island, more than eighty persons were made sick with the fever by drinking the water from a well only ten feet deep. The impure water from one spring at Trenton, New Jersey, gave the fever to nearly a hundred persons in one season. At Mount Savage, Maryland, a hundred and twenty persons were made ill by using the water from a spring near a house drain. Water from rivers and streams running near where many people live is likely to be made impure and is sure to bring sickness and death to some of those who use it. Water from a small stream at Plymouth, Pennsylvania, running past a house occupied by a typhoid patient, gave the fever to over a thousand persons in one month. The water from a small stream at Ithaca, New York, gave the fever to over thirteen hundred people in one season, and an almost equal number caught the fever in a few weeks at Butler, Pennsylvania, by drinking water from a small creek along which some sick persons lived. =Preventing Sickness from Bad Water.=--It is better to go thirsty than to drink water which is likely to cause sickness. Any water can be made safe by boiling it one minute. Boiled water is the most healthful kind of water to use. The people of China and Japan seldom use water that has not been boiled. Many cities using water from rivers run it through a layer of sand and gravel to remove the tiny things that cause so much sickness and death. This makes the water very much purer, but it is not so certain to make the water safe as is boiling it. Bad water makes nearly a quarter of a million of our people sick every year and kills twenty thousand of them. =How much Food does the Body Need?=--Most people eat too much. Overeating overworks the stomach, poisons the body, makes one feel lazy, and causes headache. If you chew your food fine and stop eating as soon as hunger is satisfied without tempting the appetite with sweets, you are not likely to overeat. About one seventh of a pound of building food is needed daily to keep the body in repair, and a quarter of a pound of fat and a pound of starches and sugars are required to help the body do a hard day's work. A half pound of bread, beans, and meat each, a pound of potatoes, a pint of milk, and a quarter of a pound of butter and sugar each, will give a working man all the food he needs for a day. [Illustration: FIG. 10.--Bird's-eye view of Plymouth, Pennsylvania, showing where the waste from one sick room was thrown on the bank of a stream which several miles below supplied the town with water and caused over one thousand cases of fever and more than a hundred deaths within seven weeks.] =Beer and Wine as Foods.=--It was once thought that beer and wine were good foods, but hundreds of late experiments show that these drinks are very poor and expensive foods. A half glass of milk is of more use to the body as a food than a full quart of beer. The use of much wine or beer may seem to satisfy the appetite because they deaden the real feeling of hunger. Neither of these drinks can be used by the young without danger of doing much harm. [Illustration: FIG. 11.--The little glass of milk contains nearly twice as much food for building flesh and blood as the large glass of beer.] PRACTICAL QUESTIONS 1. Why does the body need food? 2. Why do you weigh less after working? 3. What is oxygen? 4. From what do we get body-building foods? 5. In what is starch found? 6. How much water does the body need? 7. Where have people been made sick by using bad water? 8. How can we prevent sickness from bad water? 9. What harm does overeating do? 10. What can you say of beer as a food? CHAPTER IV FOOD AND HEALTH =Meats.=--Beef is the best of all meat for food. Nearly one fifth of it can be used to repair the worn-out parts of the body. Mutton, the meat of sheep, is almost as good for food as beef. Veal and pork also contain much body-building matter, but the stomach must work hard to prepare them for use. Fish is an excellent food, but it has only little more than one half as much flesh-building matter as good beef. Poultry is a healthful food, especially for the weak and sick, but it is more expensive than the other meats. Oysters are largely made of water and do not contain much to strengthen the body. In all meat there is some waste matter. This may harm the body if we eat too much meat. It is no longer thought healthful for most persons to eat meat more than once a day. Too much meat used daily for several years is likely to cause disease. [Illustration: FIG. 12.--Each of these articles costs the same, but the bread will furnish four times as much food for the body as the cabbage, more than twice as much as the fish, and nearly twice as much as the milk.] =The Cooking of Meat.=--The best meat if poorly cooked is unfit for eating. Broiled and roasted meats are more healthful than boiled or fried meat. Meat is broiled by holding it in a wire frame over a flame or hot coals. It is roasted by placing it in a covered pan in a hot oven for two or three hours. It is boiled by keeping it in hot water several hours. Meat is fried by cooking it in lard or other fat in a pan. Only those who have strong bodies should eat fried meat. The cheap cuts of meat from the neck, breast, and legs have about as much food matter in them as the more costly parts. Such meat may be made more tender by boiling than by roasting. =Soup.=--Soup, broth, and beef tea furnish but little food for the body. They are very useful in giving us a good appetite for the real food to be eaten later. They make the stomach go to work more quickly than other food. Soup or broth is made from meat by placing it on the stove in cold water, gradually heating it, and then keeping it hot several hours. [Illustration: FIG. 13.--Either group of foods will give the body the same strength and nourishment for work and growth.] =Vegetables.=--Some persons never eat meat of any kind because they enjoy better health when using only vegetables, milk, and eggs. Peas and beans contain much matter for making new flesh and blood and also much starch to give heat and power to the body. Potatoes form a valuable food. Roasted potatoes are more healthful than those boiled or fried. [Illustration: FIG. 14.--The amount of real food in these articles.] Radishes, onions, and cucumbers are made largely of water. Only a small amount of these should be eaten at one meal as the stomach must work hard to make use of them. Young beets, lettuce, and ripe tomatoes may be eaten by young and old. They contain useful minerals and help keep the body in a healthful condition. =The Cereals or Grain Foods.=--These foods are eaten in the form of bread, oatmeal, corn meal, rice, and breakfast foods. All of these furnish much matter to strengthen the body and make it grow. Bread and butter with rice are excellent foods for children. =Fruits.=--Very few people can remain well long without eating fruit of some kind. Ripe apples, pears, plums, peaches, berries, and cherries furnish useful salts to the body and also help the stomach and food tube do their work in a more healthful way. Fruits also increase the appetite. Green fruit and fruit which is overripe should never be eaten. =Eggs.=--Eggs form a good food for nearly everybody, but they are specially needed by the young and other persons with weak bodies. They can repair the worn-out parts of the body and also help it do its work. Eggs are most healthful when eaten raw or soft cooked. The best way to cook them through evenly is to put them in a pan off the stove and add about a quart of boiling water for every three eggs. Cover and let them cook fifteen minutes. Eggs should be kept in a cold room or cellar until used. They become stale in less than a week when left in a warm living room and may get a bad taste when only three or four days old. =Salt, Pepper, and Vinegar.=--Eating much salt is harmful. A small quantity of salt and pepper increases the appetite and makes the stomach do its work better. Children should use very little pepper and almost no vinegar and mustard. [Illustration: FIG. 15.--A bottle of beer. The dotted part at the top shows how much body-building food it contains.] =Tobacco.=--Some people think tobacco is a food because it is made from the leaves of a plant. Other people think tobacco is a food because they do not feel hungry after smoking or chewing it. The truth is that tobacco is of no use to the body as a food and may do it much harm because of the poison it contains. Tobacco satisfies hunger somewhat by deadening the parts of the body that are calling for food. =Beer.=--The people who make beer and sell it say that it is a food. Men who have no interest in selling beer, and have experimented with it to find out whether it strengthens the body, say that beer should never be used as a food. It often tends to weaken the body. Children should never use beer at any time, and older people can sometimes avoid disease by letting it alone. PRACTICAL QUESTIONS 1. Which are the best meats for food? 2. Why should we not eat meat at every meal? 3. How should meat be cooked to make it most tender? 4. How is soup or broth made? 5. Name the best vegetables for food. 6. Name some good grain foods. 7. Of what use are fruits? 8. What can you say of the use of eggs? 9. How should eggs be cared for? 10. What can you say of the use of salt and pepper? 11. Why does tobacco satisfy hunger? 12. Of what value is beer for food? CHAPTER V HOW PLANTS SOUR OR SPOIL FOOD =Germs, Microbes, or Bacteria.=--The dust and dirt of all sorts contain thousands of tiny plants too small to be seen by the eye without help. An instrument called a _microscope_ makes them appear so large that their form and growth are easily studied. These little plants are called _germs_ or _microbes_. They are also named _bacteria_. They are so small that a million laid side by side would not cover the head of a pin. [Illustration: FIG. 16.--Bacteria or microbes found in water, dust, and waste. They help change straw and other dead matter into food for plants. Much enlarged.] There are hundreds of different kinds of germs. Some are round like little balls and others are the shape of tiny rods. Many of them which look just alike act very different in growing. There are more than twenty different kinds that grow in our bodies and cause diphtheria, tuberculosis, and other diseases. We have measles and scarlet fever because we have gotten these disease germs from some one else in whom they were growing. [Illustration: FIG. 17.--Mold which grew on moist bread in two days. 5, seed bodies breaking out of the sack; 1, 2, and 4, one of the seed bodies after one, two, and four hours' growth. Much enlarged.] Most germs feed on dead matter instead of our living bodies and make it melt away or change into another form. An apple or a piece of meat thrown out on the ground will soon change and become like the earth on which it lies. The change, called decay, is caused by millions of germs. The farmer's best friends are certain germs which help make the ground rich, so that the crops will grow. =Mold.=--The dust raised in sweeping contains tiny living seedlike bodies. If these fall on bread, cheese, or fruit, and this food is afterward kept moist in a warm room for a day or two, they will grow into grayish fluffy spots. These spots are mold. The greenish white growth on the top of some canned fruit and on berries left in the warm kitchen over night is also mold. Mold is a plant which grows from tiny round bodies acting like seeds (Fig. 17). These seed bodies of mold are common in all dust and often fly through the air. On this account food should be kept covered when possible and especially when one is sweeping. Some mold gives bread, cheese, and other food a bad taste, but it will not make one sick. =How Germs Grow.=--Germs will not grow where it is very cold, but freezing the germs does not kill them. Boiling one minute kills most germs. Drying will stop the germs from growing, but will not kill all of them. Sunlight kills many of them. Moisture and warmth make germs grow rapidly. A germ in growing lengthens out a little and then divides in the middle. It does this so quickly that one germ may become two in fifteen minutes. Each of these will then divide. In this way one germ can make many million germs in a single day (Fig. 18). =The Spoiling of Meat.=--Fresh meat will not remain good even one day if left in a warm place. A large greenish blue fly seen buzzing about in warm weather will sometimes lay its eggs on meat. These will hatch the next day into little worms, called maggots. They grow rapidly and a few days later change into flies. [Illustration: FIG. 18.--Drawing of the germ at the top every ten minutes, showing how it grew into two germs in a half hour. Much enlarged.] Germs will also spoil meat not kept cold. They feed on the meat and give off a poison, making it unfit to eat. The bad odor tells when the germs are at work. Every home should have a cold cellar or an ice box to keep food from spoiling. =Saving Food from Souring.=--The souring of milk and of cooked food of any kind is due to the germs always present in the air and clinging by the thousands to unwashed dishes and hands. If meat or fruit is cooked and kept tightly covered, it will remain good for years. Many persons save fruit and vegetables for use in winter by putting them in jars, which are heated to kill the germs, and sealed tight to keep out other germs. =Yeast or the Alcohol Plant.=--Sweet cider and other fruit juices are sometimes spoiled by a plant named yeast. This plant has the form of a football and is so small that a million of its kind together would not make a mass as large as the head of a pin. It floats about in the air and is present on the skins of fruits. Yeast is also called the alcohol plant because whenever it grows in a sweet substance like fruit juice it changes part of it into a biting substance called alcohol. At the same time it gives off a gas. It is this gas which forms the bubbling or frothing in beer. [Illustration: FIG. 19.--Yeast plants used in making bread and beer. Those on the right are growing new plants. Much enlarged.] The millions of yeast plants in the yeast cake bought at the store, when put into the dough for bread, grow and form gas. This pushes the bits of dough apart and makes it light. The little alcohol formed is all driven off in the baking. The alcohol which yeast forms by growing in sweet cider is in a few weeks changed to vinegar by other germs called the vinegar plants. Sour cider may make those who use it sick and drunk because it contains alcohol. Yeast makes wine out of grape juice. PRACTICAL QUESTIONS 1. Where are germs found? 2. What is the form of microbes? 3. Name some diseases caused by germs. 4. What is mold? 5. Why should food be kept covered when not in use? 6. What causes meat to spoil? 7. How may fruit be kept from spoiling? 8. Where is yeast found? 9. What effect has yeast on fruit juice? 10. Why should you not drink sour cider? CHAPTER VI MILK MAY BE A FOOD OR A POISON =Of what Milk is Made.=--Milk is the most perfect food known. It contains everything needed to build and strengthen the body. In one gallon of milk there is about one teacupful of pure fat, nearly the same amount of sugar, one teacupful of body-building food needed to make muscle and blood. There is also some lime and other mineral matter to make the bones of the young grow strong. The remaining seven pints are water. =Kinds of Milk.=--When milk is left standing in a jar for several hours, much of the fat, which is present in the form of tiny balls, rises to the upper part. This upper layer of milk full of fat is called _cream_. If this is removed, the rest is called _skim milk_. Milk after standing in a warm place one or two days becomes sour. It is then sometimes put into a tight box or barrel and beat in such a way as to break up the little balls of fat. These are then pressed together into a mass called _butter_. It requires a whole gallon of milk to make one teacupful of butter. The milk remaining after the butter is taken out is called _buttermilk_. Cheese is made from milk. [Illustration: FIG. 20.--Two kinds of milk, showing the amount of fat in each.] =Milk as a Food.=--Milk is a healthful drink for nearly every one and especially useful for those with weak bodies. During sickness it is sometimes the only food the patient can take. It is well for children to use two or three glasses of milk daily with their meals. It should be sipped slowly so it will mix with the fluid in the mouth and not form lumps called curds in the stomach. A quart of milk contains more food for the body than a half pound of good beefsteak. A pint of milk will supply the body with about as much food as a pint of oysters. A bowl of milk and a half loaf of bread is a healthful supper for a boy or girl. Skim milk and buttermilk are healthful drinks which furnish much food for building bone, blood, and muscle. [Illustration: FIG. 21.--Germs which grow in milk and make it sour.] =When Milk is a Poison.=--In New York, Cincinnati, and Chicago it has been noticed for many years that large numbers of babies become sick in warm weather and many of them die. The doctors learned that most of the babies taken sick were being fed on cows' milk because their own mothers did not have enough for them. It was then found that the sick babies had been using milk from dairies where the stables were dirty, the cows soiled, and the hands of the milkers unclean. On this account much dirt got into the milk. Babies fed on clean milk from clean cows kept in clean stables remained strong and well. By much study the doctors learned that _dirty milk is poisonous milk_. The poison is made by the germs or bacteria living by the millions in unclean stables and in milk buckets not well washed in boiling water. Dirty milk becomes most poisonous in hot weather because warmth makes the germs grow very fast and become so numerous that millions are present in a teaspoonful of milk. =Keeping Milk Clean.=--During one week of hot weather in Cincinnati, over a hundred babies were poisoned with dirty milk. In the same week twice this number were made sick by unclean milk in Philadelphia. During the hot part of the year in our country bad milk kills more than a half dozen babies every hour of the day and night. The only way _to have milk clean is to have clean stables with clean cows, milked by clean hands, and the milk handled in clean pails, cans, and bottles which have been scalded after being washed_. The milk must then be kept cold until used, so that the germs will not grow in it. =Saving the Baby from Bad Milk.=--If possible, milk should be bought for the baby in bottles sealed with a pasteboard lid. If milk turns sour the same day it is delivered, it is not fit for the baby to take. Heating it makes most milk safer for use. The heating of milk to kill most of the germs is _pasteurizing_ it. It should be kept very hot for about fifteen minutes, but should not be allowed to boil. It should be cooled by placing the vessel on ice or in cold water. The baby's bottle and nipple should be washed in cold water and then well scalded immediately after being used. The bottle, the nipple, and the milk should be kept away from flies and dust. One fly has been known to carry on its body more germs than there are leaves on a large tree. [Illustration: FIG. 22.--Plan of the prison at Easton, Pa. The crosses show into which cells the flies brought typhoid germs from the sewer and made the prisoners sick with fever.] =Flies and Fever in a Prison.=--In August, 1908, thirteen prisoners in the jail at Easton, Pennsylvania, were taken ill with typhoid fever. They had not been near any sick persons and their food and water were found to be pure. All those sick were in cells in one end of the prison. About twenty feet from this end a sewer had been uncovered two weeks before and left open. This sewer carried the waste from the hospital where several patients were sick with the fever. Flies fed on the waste in the sewer and then with the germs sticking to their feet flew into the cells of the prisoners and walked over their cups, spoons, and food. A little girl who played near this open sewer and shared her lunch with the flies had a severe attack of fever two weeks later because the germs scraped from the flies' feet on her food got into her body and grew. =Milk and Disease.=--We must be very careful to get not only clean milk but milk from healthy cows milked by persons who have no typhoid fever, scarlet fever, or diphtheria in their homes. If only one or two disease germs get into the milk from the hands of those who have nursed the sick, these will grow into immense numbers in a single day. Many of those who use the milk will then become ill. Hundreds are made sick in this way every year. PRACTICAL QUESTIONS 1. Why is milk a good food? 2. What does a gallon of milk contain? 3. What is cream? 4. How is butter made? 5. For whom is milk specially good? 6. How does milk become poisonous? 7. Why is dirty milk more poisonous in hot weather? 8. Tell what harm unclean milk does. 9. How may milk be kept clean? 10. Explain how milk is heated to make it safe for use. 11. Show how flies may cause fever. 12. Tell how milk may carry diphtheria into our homes. CHAPTER VII HOW THE BODY USES FOOD =Organs for making ready the Food.=--Before the food can get into the blood and be carried over the body to feed the muscles and the brain, it must be made into a fluid. This changing of the solid food into a liquid by the stomach and other organs is called _digestion_. The organs which do this work are known as _digestive organs_. They consist of a _food tube_ and several bodies called _glands_. =The Food Tube.=--The food canal is about thirty feet long. Its first part, the _mouth_, opens back of the tongue into the throat, named the _pharynx_. This leads into a tube, the gullet, passing down through the back part of the chest into the _stomach_ below the diaphragm. The stomach is a bent sac opening into a tube over twenty-five feet long called the _bowels_ or _intestines_. This tube is folded into a bunch which fills a large part of the cavity of the abdomen. [Illustration: FIG. 23.--The plan of a gland. _a_ carries blood to the gland and _v_ takes it away after the gland has taken out what it needs. On the right side the top of the gland has been cut off.] =The Glands or Juice Makers.=--A gland is a little tube closed at one end, or a bunch of such tubes, which can take something out of the blood and make it into a juice. A gland under each ear and four others near the tongue make the juice called _saliva_ which flows into the mouth through tubes. A long, flat, pink gland back of the stomach is called the _sweetbread_ or _pancreas_. This and a large brown gland, the _liver_, empty their juices into the intestines. The whole inner surface of the stomach and intestines is lined with tiny tubes, the glands. The juice of these with that of the other glands softens the food and makes it into a liquid. =The Work of the Mouth.=--The mouth has three things to do: It should break the lumps of food into fine bits so it can be well wet with the slippery fluid called _saliva_ and also easily swallowed. It must roll the food about so that it gets soaked with saliva. It must hold the food long enough to get much taste from it because this starts the juices to flowing into the stomach. Food gives out its taste only after it is changed to a liquid. It should not be washed down with water, as this weakens the juices in the stomach. [Illustration: FIG. 24.--The three glands which make the saliva for acting on the food in the mouth.] No food should be swallowed until it is broken into bits nearly as small as the head of a pin. Some foods, such as cheese, bananas, and nuts, should be made even finer than this. There is nothing in the stomach to crush to pieces large lumps of food. The juices of the stomach can do their full work only when the food is well chewed in the mouth. [Illustration: FIG. 25.--Photograph of a chestnut chewed a half minute by a boy who had poor teeth because he had not taken care of them. The lumps are so large that the juices of the stomach could not dissolve them.] =The Chewing of Food keeps away Sickness.=--Bread, meat, and potatoes should be cut into pieces no larger than half the size of your thumb and each piece put separately into your mouth with a fork. It should then be chewed from twenty to thirty times before another piece is put into the mouth. Food treated in this way will not cause headache or a sickness in the stomach called _indigestion_ or _dyspepsia_. It is said that there are so many persons with this kind of sickness that more than $5,000,000 are spent every year for medicine to help them. Too little chewing of the food while you are young may not cause many aches or pains, but if you form the habit of rapid eating it is hard to learn to eat slowly. No one who chews his food poorly can avoid sickness long or grow well and strong. [Illustration: FIG. 26.--Photograph of a chestnut chewed a half minute by a boy with good teeth.] =The Work of the Stomach.=--When the food is swallowed, it passes through the gullet into the stomach. This is a sac holding more than a quart (Fig. 27). It is made of an outer wall of muscle and an inner skinlike coat full of tiny tubes called _gastric glands_. Millions of these give out drop by drop a watery fluid named _gastric juice_. This juice begins to flow as soon as we smell or taste food and continues to drop out as long as there is any food in the stomach. The use of the gastric juice is to help change part of the food into a more watery fluid. To do this it must be well mixed with the food. This mixing is done by the muscles in the outer wall of the stomach (Fig. 29). They squeeze together and then loosen up in such a way as to move the food about and turn it over until every particle is wet again and again with the gastric juice. =How long Food stays in the Stomach.=--A ring of muscle around the end of the stomach keeps the food from escaping until it has become a thin grayish liquid. The stomach can finish its work on some kinds of food in one or two hours. With other foods it must work four or five hours. The stomach can finish its work on soft boiled eggs, milk, roasted potatoes, and broiled lamb within two hours. With pork, veal, cabbage, and fried potatoes it must work four or five hours. When a person is sick the stomach is weak, and he should have only the food which causes the stomach the least work. =The Work of the Intestines.=--The last part of the work in getting the food ready for the blood is done in the long folded tube known as the intestine (Fig. 27). Here juices coming from the pancreas and liver mix with the food and change into a liquid those parts not acted on in the stomach. The intestine does quite as much work as the stomach. Sometimes when the stomach is sick, too much work is put off on the intestines and then they become sick and give much pain. The pint of watery fluid from the pancreas and the quart of greenish yellow fluid called _bile_ given out by the liver are carried through two tubes into the intestine (Fig. 27). To mix these juices with the food the intestine is being swung gently back and forth and the walls squeezed together by muscles forming its outer coat. As soon as the intestine has finished its work the food begins to enter the blood. [Illustration: FIG. 27.--The organs which get the food ready to enter the blood.] [Illustration: FIG. 28.--Showing how the food in the dog is carried from the intestine to the liver and heart. The white tubes carry the fats up to the vein in the neck, and the dark tubes which are veins carry the other part of the food to the liver.] =How Food gets into the Blood.=--An hour or two after food has entered the intestine it is almost as thin a fluid as milk. Millions of tiny fingerlike growths stick out from the inner side of the intestines and drink in the watery food. These little fingers for drinking up the food are scarcely one fourth as large as the point of a pencil. They are called _villi_. The villi are filled with blood tubes having thin walls. The food passes through these walls into the blood stream. Much of it then goes to the liver, but the fatty parts flow up a tube along the backbone and empty into a blood tube in the neck. From the neck and the liver the food goes with the blood to the heart which sends it to all parts of the body. =What the Liver does.=--The liver is a dark red body nearly as large as the upper half of your head. It lies just below the diaphragm. It works night and day helping to keep the inner parts of the body clean and at the same time deal out food. The liver takes some waste out of the blood and sends it out into the intestine with the bile. When there is no food in the intestine, the bile is stored up in the _gall bladder_ under the liver. The liver changes certain waste matter in the blood into such form that other organs can cast it out of the body. It also stores up certain parts of the food coming from the intestines and gives it out to the body little by little as it is needed. =When and How much to Eat.=--When the food organs do not do their work rightly, the whole body becomes sick. Eating too much overworks the stomach. It becomes so full that the food cannot be moved about and well mixed with the juices. Germs then work on the food and make it sour. In fact the germs may change part of the food into a poison. This poison will cause headache and a bad feeling. Do not form a habit of taking powders to cure headache. They are likely to hurt the heart. Take less food, eat it more slowly, and do not wash it down with drink. Stop eating before your stomach feels full. Each meal gives the stomach about four hours of work to do. It then needs one hour of rest. This shows that the time from one meal to the next should be about five hours. Very young children and sick persons need food oftener. Boys and girls should not eat candies, cake, or other food between meals. It spoils the appetite and is likely to get the stomach out of working order. =Danger Signals.=--A white or yellowish coat on the tongue, a bad breath, pain in the bowels, or a headache is a danger signal. It tells that the food organs are not doing their work as they should and unless help is given sickness is likely to occur. Medicine may help, but using foods easy to digest, eating less, chewing more, and getting plenty of exercise in the fresh air are likely to be the greatest aids to health. =The Chewing of Tobacco and Digestion.=--Some men chew tobacco as much as ten hours every day. The taste of the tobacco makes the saliva flow from the glands into the mouth. This dissolves the poison out of the tobacco and it is then spit out. If the tobacco-soaked saliva were all swallowed, the man would be poisoned. The chewing of tobacco causes the loss of much saliva which is needed to help digest the food. Anyone who tires his jaw by chewing tobacco is not likely to chew his food well. Some of the poison in the tobacco is taken into the body through the blood vessels in the lining of the mouth. This is shown by the fact that a boy not used to tobacco becomes very sick after he has chewed a mouthful for only ten minutes. =Smoking and Digestion.=--Some persons think that the smoking of a cigar after a meal helps digestion. It may do so in some cases. If a lawyer is much excited about a case he is trying, or a business man is in trouble about his losses, the thinking causes the blood to flow to the head when it is needed in the stomach to give out digestive juices. The taste of the tobacco smoke may cause some gastric juice to run out into the stomach, but at the same time it is likely to hurt the nerves of taste so that food cannot give so much enjoyment as when the nerves are unharmed. Although smoking may at the time help digestion a little, the poison in the tobacco may afterward injure the body. This poison is especially harmful to growing bodies, and boys who are wise will refuse to smoke on all occasions. =Beer and Digestion.=--Some people drink beer with their meals because they think it makes the food taste better. It really prevents them from getting the full taste of the food because they wash it down before it is well soaked with the saliva. [Illustration: FIG. 29.--The stomach, showing the arrangement of the muscular fibers which alcohol may hinder from doing good work. At the right a piece is cut out of the top layer of muscle.] The flavor of beer may sometimes cause an extra flow of gastric juice into the stomach, but the alcohol in the beer is likely to make the movements of the stomach slower. This prevents the food from being well and quickly mixed with the juices. Several glasses of beer used at one meal will make the stomach do its work very slowly, and it will not do it well. =Wine and Digestion.=--Wine is taken by some people to give more appetite for food. It is likely, however, to do more harm than good because the alcohol in it makes the muscles which mix the food in the stomach act more slowly. Some of the food may sour before it gets wet with the juice. Much wine used at a meal is always harmful. =Natural Appetite.=--If one is in health, he should feel a desire for his food at every meal. This desire for a reasonable amount of food is a natural appetite. Fresh air and exercise will do much to give one the right kind of an appetite. The eating of much sweets and the breathing of bad air are likely to spoil the appetite. The use of some things, such as opium, tobacco, beer, wine, and whisky, creates an unnatural appetite. That is, after one has used these articles a few months he cannot stop their use without great suffering. The younger the person, the sooner the appetite becomes fixed. For this reason _young persons should never use tobacco or alcoholic drinks of any kind_. PRACTICAL QUESTIONS 1. What is digestion? 2. Name the parts of the food tube. 3. Where does saliva come from? 4. Explain how the food is acted on in the mouth. 5. Why should food be well chewed? 6. What forms the gastric juice? 7. Of what use is the gastric juice? 8. How long does food stay in the stomach? 9. Name some foods easily digested. 10. What does the intestine do? 11. What are villi? 12. Tell how the food gets into the blood. 13. Of what use is the liver? 14. Why should we not eat too much? 15. Should we eat between meals? 16. Give three reasons why you should not use tobacco. CHAPTER VIII THE CARE OF THE MOUTH =Sickness often begins in the Mouth.=--A clean mouth and sound teeth have much to do in keeping one well. The germs which cause nearly a half million deaths in the United States every year enter the body through the mouth. If the mouth is unclean, only one or two disease germs entering it may remain there and grow. [Illustration: FIG. 30.--The teeth of the upper jaw at eleven years of age.] It is just as important to wash the mouth two or three times each day as it is to wash the hands and face. A few germs of diphtheria, sore throat, or tuberculosis are likely to get into the mouth any day, but if the mouth and teeth are well washed with a brush morning and night, the germs will not have time to grow and cause sickness. =The Teeth.=--The first twenty teeth that appear are called the _milk set_. The eight front teeth grow out during the first year of life and back of these twelve others appear during the second year. Between the seventh and the tenth year all of the milk teeth are lost because others grow beneath them and push them out. [Illustration: FIG. 31.--The full set of teeth on the right side at twelve years of age. The numbers show at what year of age each one grows out of the gum.] The first four teeth of the second set appear in the sixth year, just behind the last milk teeth (Fig. 30). These teeth should be watched very closely and at the first sign of decay you should go to the dentist. As the milk teeth get loose and come out, the second set of teeth take their places. If you are ten or eleven years old, you should have twelve good teeth in the upper jaw and the same number below. The last ones to break through the gums are the four wisdom teeth at the back of the mouth. They appear after the seventeenth year. The front teeth are called _incisors_ because they are used to cut the food. The back teeth are named _molars_ because they are used in grinding the food. [Illustration: FIG. 32.--Photograph of teeth not kept clean, showing how germs and a sour substance called acid eat holes in them and thus cause decay and toothache.] =Toothache.=--Toothache is a common ailment, and yet it can be entirely prevented. A tooth does not ache until it has a hole in it. The tender nerve within gives us warning that it is being hurt. The dentist can stop the ache and mend the tooth so that it will not ache again. Look at your teeth every month and feel about them with a wooden tooth-pick to know when the decay begins. If the little holes are mended as soon as found, you will never have toothache, and you can keep your teeth as long as you live. [Illustration: FIG. 33.--Slice down through a tooth showing _f_, the enamel, and _d_, the soft pulp with nerves and blood tubes from the root at _h_.] =How to keep the Teeth Sound.=--Every tooth is covered with a layer of hard shining substance called _enamel_ (Fig. 33). So long as this is unbroken the softer bony part of the tooth cannot decay. At the base of the tooth where the gum joins it the enamel is very thin, so that the scratch of a pin or other instrument may break it. Never pick the teeth with a pin or needle. The biting off of thread, finger nails, and other hard material may crack the enamel. It may also be softened and eaten away by acid formed where food remains about a tooth. For this reason a quill or wooden pick or piece of tough thread, called _dental floss_, should be used to clear the teeth of food after each meal. Slimy matter collects over the whole surface of the teeth, and is likely to cause decay in spots unless it is cleaned off night and morning with brush and water. The chewing of dry crusts of bread or crackers strengthens the teeth and keeps off decay. =Why Candy and other Sweets cause the Teeth to Decay.=--A sour substance called acid usually starts the decay of a tooth by eating through the enamel. Germs change sugar and other sweets into an acid. The acid is not made at once. An hour or more is needed for the germs to grow to form the acid. If, after eating sweet foods, the mouth is well cleaned, no acid will be formed. Sugar and candy do not, therefore, spoil the teeth unless it is left sticking about them. =How to brush the Teeth.=--Every boy and girl should own a toothbrush. _The teeth should be brushed every night and morning and kept white._ Yellow or gray slimy teeth are very ugly. The teeth should be brushed on the inside as well as on the outside. It is best to brush the teeth crosswise for two minutes and then spend another two minutes brushing the upper teeth downwards and the lower teeth upwards. This prevents pushing the gum away from the teeth. Plenty of water should be used with the brush, and a little good powder is helpful once a day. =How the Dentist can Help.=--Sometimes the milk teeth do not get loose so that they can be pulled with the fingers at the right time. The second teeth then come in at one side and may never get straight in place. They then spoil the appearance of the face and do poor work in chewing. The dentist should be asked to help straighten the teeth as soon as they appear crooked. [Illustration: FIG. 34.--Exact drawing of the teeth of two persons. Those in the lower picture began to decay over twenty-five years ago and they were then filled so as to remain perfect. The teeth in the upper picture began to decay less than ten years ago but were not filled.] It is wise to have the dentist examine the teeth once or twice every year and remove a limy substance called tartar collecting at their base. The dentist can stop the decay in a tooth by cleaning out the little hole and filling it with gold or some other material. It may cause a little pain and expense to have the teeth filled, but it will save a hundred times as much pain and expense later. The six year molars need special care as they are likely to decay early. Even the milk teeth often need filling so that they will not be lost too soon. =Bad Teeth cause Sickness.=--When anything decays, it is full of germs, and they are always giving off some poison. The poison may hurt the body and is likely to make parts of the mouth sore and tender so that other germs of disease can break through into the flesh. Disease germs can easily lodge in the holes of decaying teeth, grow in numbers, and finally cause diphtheria, sore throat, or other ailments. Four out of every five children suffering from diphtheria or other throat or ear troubles are found to have from one to ten bad teeth. You must keep good teeth if you wish to be well and strong. =The Value of Sound Teeth.=--Sound teeth which will do good work in chewing food are worth more than a foot or an arm. If the foot or arm is lost, the body is likely to get well and be as healthy as ever. _The health of the whole body depends upon the work done by the teeth._ Unless they do their part the stomach cannot get the food ready for the blood. A part of badly chewed food is turned into a poison farther down in the food canal. This is what makes many people feel so tired and miserable much of the time. Hundreds of men have been refused admission to our army because they have poor teeth. Soldiers must be strong and well to take long marches and fight battles. Sound teeth give strength and health. PRACTICAL QUESTIONS 1. Why should the mouth be washed out every day? 2. When do the milk teeth appear? 3. When are the milk teeth lost? 4. How many teeth have you? 5. How many show signs of decay? 6. How may toothache be prevented? 7. How may the teeth be kept sound? 8. Why do sweets cause the teeth to decay? 9. How should you brush your teeth? 10. Why should the dentist examine your teeth every year? 11. Why are sound teeth of great worth? CHAPTER IX ALCOHOLIC DRINKS =Drink needed for Health.=--Water in the form of sweat and in other ways is constantly passing off from the body. This water carries with it the waste matter which, if it remained, would poison the body. There is some water in the food we eat, but not enough to supply the wants of the body. Some persons think that the body needs beer or wine to keep it in good order. These liquids, as well as whisky, brandy, and rum, are called _alcoholic drinks_. The latest experiments and studies show that the body never needs alcoholic drinks to keep it in the best of health. These drinks sometimes make the body sick, and if much alcohol is taken at one time, the person becomes dizzy, staggers, and may fall down and go to sleep. =The Desire for Drink.=--When parts of the body have too little water, there is a longing for drink. This is called _thirst_. As soon as a cup of water is drunk the desire is satisfied. There is no danger of drinking too much pure water. Persons who have been accustomed to use alcoholic drink have a thirst which water does not satisfy. It is an _unnatural thirst_. Even beer or wine will not satisfy such a thirst except for a few minutes. Very often a person's thirst is not satisfied until he has used so much wine or whisky that he becomes dull and unsteady in his walk. He is then said to be drunk. [Illustration: FIG. 35.--Yeast plants growing as in the making of beer and wine. Much enlarged.] =How the Yeast Plant makes Alcohol.=--In the cake of yeast bought at the grocery there are millions of tiny plants, each shaped somewhat like a potato. This strange little plant will grow very rapidly when put into any sweet watery substance. It sends out a bud which grows larger and larger until in a half hour the bud is as large as the old plant. It may then break loose and grow other buds, just like the mother plant. When yeast grows, it changes the sugar or sweet part of the water into alcohol and a gas called carbon dioxide. It is this gas which makes beer foam and bubble when opened. All alcohol used in beer, porter, ale, wine, brandy, rum, gin, and whisky is made by yeast plants. [Illustration: FIG. 36.--Photograph of sprouted barley grains called malt.] =How Beer is Made.=--There is more beer used than any other alcoholic drink. It is cheap and is much weaker in alcohol than wine or whisky. Only about one twentieth part of beer is alcohol. [Illustration: FIG. 37.--Photograph of a spray of hops, which are used to flavor beer.] In making beer, a sweet watery mixture is first prepared by mashing sprouted barley grains in water. Barley or any other grain forms sugar as soon as it begins to grow. Yeast plants are added to the sweet mixture. By growing they change some of the sugar into alcohol. Hops are also put in to give the beer a fine flavor. After a time the clear liquid is separated from the barley grains and hops and put into tight casks and bottles. =The Making of Wine.=--Wine contains from two to four times as much alcohol as beer. Most of the wine is made in California, France, and Germany because grapes grow better in these countries than elsewhere. Wine may be made from the juice of any fruit, but the grape is generally used. [Illustration: FIG. 38.--The quantity of grapes required to make this glass full of wine.] The grapes after being picked are thrown into large tubs and crushed so that the juice runs out. The wild yeast always present on the grape skins begins to grow in the juice and change some of the sugar into alcohol. This work of the yeast lasts from one to eight weeks. At the end of that time, the grape juice has become a kind of poor wine, consisting of alcohol, water, grape flavor, and some acid. To make the wine good it must be drawn off into casks, where the yeast causes further changes during several weeks. It is then put into bottles, where it should remain about five years to get the right flavor. =Sherry= is a strong wine used in flavoring food, such as puddings and sauces. A few teaspoonfuls of this wine will make a child drunk. The wines made at home from elderberries, blackberries, and cherries contain alcohol which will do just as much harm as that in the purchased wines. =How Brandy is Made.=--Brandy contains more alcohol than wine and almost as much as whisky. In fact brandy is only very strong wine. After the yeast plants have formed as much alcohol as they can in grape juice it becomes so strong that it kills them. This wine is then heated in such a way as to separate some of the water from it. The taking away of the water leaves the wine stronger in alcohol and it then forms brandy. [Illustration: FIG. 39.--The shaded part at the bottom of each bottle shows the amount of alcohol in the drink.] [Illustration: FIG. 40.--A still used in making whisky or brandy. The heat makes the alcohol fumes or vapor rise and pass over through the pipe coiled in a vessel of cold water. The cold changes the vapor to a liquid which is whisky.] =Whisky and Rum.=--These two drinks are strong in alcohol. Nearly one half of each is pure alcohol. Whisky is usually made from rye, corn, or wheat, or all three together. They furnish the food in which the yeast grows and makes alcohol. This watery mixture of grain and alcohol is then heated and the vapor or steam forms whisky after it goes off through a pipe into another vessel. This kind of heating is _distillation_. Rum is formed in somewhat the same way from molasses or cane juice. PRACTICAL QUESTIONS 1. Name some alcoholic drinks. 2. What is an unnatural thirst? 3. Explain how the yeast plant forms alcohol. 4. Tell how beer is made. 5. Tell how wine is made. 6. What is brandy? 7. Which drinks contain most alcohol? CHAPTER X ALCOHOL AND HEALTH =The Money spent for Alcoholic Drinks.=--If the money spent for alcoholic drinks were all collected together in silver dollars, it would more than fill ten schoolrooms of average size. Not only rich men spend large sums yearly for fine wines and brandies, but also the poor give their money for beer and other drinks which the body does not need. When parents waste their money on drink, they cannot buy the food and clothes needed to keep their families strong and well. In this way strong drink causes much sickness and suffering and sometimes even death. =Alcohol injures the Body.=--Some persons drink very little beer or wine, so they seem to have but little effect on the health. Others use strong drink every day and for a few years they may remain quite well. Later ill health often comes on, and they then find that some of the organs have been so much hurt that they will never be quite well again. A few years ago a group of fifty well-known men in the United States spent much time and thousands of dollars to learn how much alcohol was harming our country. After much study among many people they announced that there were about one million men and boys whose health had been injured by strong drink, such as beer, wine, and whisky. Because strong drink causes so much sorrow and sickness several states have passed laws forbidding its sale, and saloons have been closed by laws in parts of many other states. =How Alcohol affects Kittens.=--The body of a kitten is made very much like the body of a child. It has just the same organs that a child has, and they do the same kind of work. Doctor Hodge, a well-known scientist of Massachusetts, therefore concluded that alcohol would act on kittens in the same way as it would on a man or boy. The doctor got two healthy kittens and fed them a little alcohol every day for nearly two weeks. In a few days they stopped being playful, did not grow, and did not keep their fur clean and smooth as healthy kittens do. After using alcohol several days they became very ill. This experiment showed that alcohol stops kittens from growing and robs them of good health. =How Alcohol hurts Dogs.=--Doctor Hodge fed a little alcohol to two dogs nearly every day for three years. He also kept the brother and sister of these dogs, but gave them no alcohol. All the dogs had the same kind of food and were treated alike except that one pair got alcohol and the other pair did not. The two drinking dogs got sick more easily and staid sick much longer than the temperance dogs. The drinking dogs became lazy, and timid, while the others were strong, full of fun, and brave. Within four years the drinking dogs had born to them twenty-seven puppies, but only four of them lived to grow up. The others were too weak or sickly to live. During the same time the temperance dogs had forty-five puppies and forty-one of these lived. This shows that strong drink will not only injure the bodies of those who take it, but will make their children weak and sickly. =The Use of Strong Drink causes Disease.=--Many persons who take beer or wine every day become fat. They think this is a sign of health. It is really a sign of disease. They become short of breath. They can no longer run so fast or do so much work because the heart is covered with fat and even some of its wall is changed to fat. For this reason the heart cannot do its work easily or well. The kidneys which take the waste out of the blood often become injured by alcohol and a disease causing death follows. Sometimes the stomach becomes diseased so that it cannot do its work. This makes the whole body sick. The hardening of parts of the liver is nearly always caused by the use of beer. The liver is sure to suffer if one uses much alcoholic drink because the alcohol goes direct from the food tube to the liver. Long use of strong drink may bring on disease in the brain and nerves. =Alcoholic Drinks may cause Death.=--Every ten years the government appoints persons to visit each home in our land to take the census. A part of this census report consists of a table showing the disease of which people died. It is from the census report that we know that hundreds of people die every year from the use of alcohol. =Danger to Health in beginning the Use of Strong Drink.=--A large number of people take a drink of beer or wine occasionally because they do not see that it hurts the body. No one expects to become a steady drinker or a drunkard when he begins to drink. Reports show that every drunkard begins his downward course by taking a few drinks occasionally. Thousands of persons begin a drunkard's life every year because the appetite leads them on gently until they become slaves and cannot let drink alone. CHAPTER XI TOBACCO AND OTHER DRUGS WHICH INJURE THE HEALTH [Illustration: FIG. 41.--The tobacco plant.] =How Tobacco is Made.=--Tobacco is made from the leaves of the tobacco plant. The plant may grow as tall as a man and bear more than a dozen leaves. Each leaf is two or three times as large as your hand. The seeds are planted in the springtime, and the plants are ready to be cut in the autumn. Most of our tobacco is raised in the Southern states and Cuba. After cutting, the tobacco must be dried and cared for in a special way to give it the right flavor. It is then sent to factories and made into cigars, smoking tobacco, or chewing tobacco. =How Tobacco is Used.=--Many million dollars are spent every year by the people of our country for tobacco. Most of the tobacco is used in smoking. Some men smoke it in pipes, while others smoke it in the form of cigars or cigarettes. Many men chew tobacco. When used in this way, something like licorice is generally mixed with the tobacco to give it a more pleasant taste. Sometimes the dry tobacco is ground into a fine powder called snuff. This is used by both men and women. =Tobacco contains a Poison.=--When boys chew or smoke tobacco for the first time, it always makes them sick. Chewing or smoking for fifteen minutes will make them grow dizzy and weak and feel so sick that they must lie down for a long time. The sickness is caused by a poison called _nicotine_ which is present in all tobacco. Much of this poison may be soaked out by boiling the tobacco in water. A cup of water in which a pipeful of tobacco has been boiled will kill goldfish in an hour when poured into a gallon jar of water with the fish. There is enough poison in a handful of tobacco to kill a boy who is not in the habit of using it. =Why Men can use Tobacco without becoming Sick.=--Experiments upon animals have shown that the body can learn to use a poison and not become sick from it. The poison of a rattlesnake is deadly to most animals; but if a tiny bit of the poison is put under the skin of the rabbit one day and then on each succeeding day a little larger dose of the poison is given the rabbit for a long time, the animal will become so accustomed to the poison that the bite of a rattlesnake will not harm it. It is the same way with tobacco. Little by little the body learns to overcome the effects of the poison, but much use of tobacco is likely to hurt certain parts of the body. =Tobacco is Harmful to the Young.=--A dose of poison which will kill a child may do but little harm to a man. Tobacco is certain to hurt boys more than it does men. The poison makes the body grow slower. [Illustration: FIG. 42.--There is more poison in the one on the right than in the one on the left.] A large number of measurements made by Doctor Seaver showed that the boys who did not use tobacco gained in four years one twentieth more in weight and one fourth more in girth and height than the users of tobacco. These boys were between sixteen and twenty-two years of age. It is likely that tobacco will have a more harmful effect on younger boys. =Laws to keep the Young Healthy.=--Boys ought to be wise and brave enough to let alone what keeps their bodies from growing and hurts their health, but some will not do it. For this reason some countries are trying to save the health of their boys by making laws against the use of tobacco. The Germans a few years ago passed a law in their land forbidding all boys and girls under sixteen years of age to use tobacco in any form. Seeing the good results of this law in Germany and the harm that tobacco was doing the boys in the United States, the Emperor of Japan on the 6th of March, 1900, proclaimed this law: "The smoking of tobacco by minors under the age of twenty is prohibited." In our own country several states have passed laws against the use of cigarettes by boys. One country after another is learning that if they want strong men, to fight, to work, and to win, tobacco must not be allowed to weaken the bodies of the young. =How the White Man becomes a Slave.=--Before the Civil War the black men of the South were slaves. They could not do as they pleased because they belonged to their masters whom they must obey or else they would suffer punishment. No boy can begin the use of tobacco without the danger of becoming a slave to it. The use of tobacco either by chewing or smoking gradually causes in any one the growth of an appetite which makes him feel miserable and unhappy unless it is kept satisfied. It can be satisfied only by the use of more and more tobacco. Many men would like to quit the use of tobacco if they could do so without suffering. They are slaves, and tobacco is their master. =Cigarettes and Health.=--A cigarette is a tube of paper filled with tobacco. The tobacco is usually not so strong as that used in cigars and pipes. For this reason, boys like it better, and because it is so mild they draw the smoke down into the lungs. This gives the poison a better chance to be taken up by the blood. On this account, and because one is likely to smoke oftener when he smokes a small piece of tobacco, cigarettes are thought by some to be more harmful than the use of tobacco in pipes and cigars. =Tea and Coffee.=--Tea is made from the dried leaves of the tea plant. Tea plants are raised in North Carolina, China, and Japan. The drink called tea used at the table is made by pouring boiling water on the tea leaves. The leaves should not be boiled as this draws out a substance which keeps the stomach from doing its work in the right way. Coffee is the seed of a plant growing in South America and Asia. It is roasted, then ground, and boiled in water to make the drink called coffee. [Illustration: FIG. 43.--Branch of a tea plant.] [Illustration: FIG. 44.--Branch of a coffee plant with bunches of coffee berries near the bottom.] Children should not use either tea or coffee as they are likely to hurt the stomach and may injure the heart. One or two cups of tea or coffee daily seem to have little or no bad effect on the health of most grown persons. Coffee taken at supper may keep one awake by sending too much blood to the brain. =Opium and Morphine.=--Opium is a dangerous drug which is got from the heads of the white poppy plant grown mostly in the far East. From gashes cut in the poppy heads a juice runs out and hardens into a gum from which the pure drug is made. Some persons smoke opium for the drowsy and pleasant feeling it gives. Its use is very hurtful and ruins both body and mind. _Morphine_ is a pure form of opium. Persons take it to kill pain and make them sleep. You should never take it except when given by the doctor, as a habit is quickly formed which will make you miserable through life. =Patent Medicines.=--These are medicines advertised to cure ailments which generally cannot be cured by drugs. They are the medicines much advertised in the newspapers and magazines. Never use them unless your doctor tells you to do so. Many of them contain harmful drugs, such as morphine and alcohol. When you are sick, go to your doctor for advice. PRACTICAL QUESTIONS 1. Explain how tobacco is raised. 2. How is tobacco used? 3. How does tobacco affect a boy using it for the first time? 4. What is the name of the poison in tobacco? 5. Tell how tobacco keeps boys from growing. 6. What countries do not allow boys to use tobacco? 7. What is meant by being a slave to tobacco? 8. What is tea? 9. What is coffee? 10. Why should you not use opium or morphine? CHAPTER XII THE SKIN AND BATHING =Parts of the Skin.=--The skin is about as thick as the leather of your shoe. It is fastened to the muscles beneath with fine white threads like spider webs. This is called _connective tissue_ because it connects the skin to the lean meat. The skin is made of two layers (Fig. 45). The upper layer is formed of cells. This is named _epidermis_ or _scarfskin_. The deeper layer is made largely of fine threads woven together. It is the _true skin_ or _derma_. There is no blood in the scarfskin, but there is a network of blood tubes in the true skin. It is the crowding of these with blood that makes the skin look so red when we get hot or excited. =The Use of the Skin.=--The skin has three chief uses. It protects the softer parts of the body from being hurt by rough or hard things which might touch it. It contains the organs of feeling. It helps keep the right amount of heat in the body. [Illustration: FIG. 45.--A thin slice through the skin, showing sweat glands, a nerve, and blood-tubes. Much enlarged.] The top part of the skin is dry and dead. This gives better protection than if it were moist and tender. Particles of it are wearing out and dropping off while other bits are growing beneath to take the place of the worn-out parts. The more this top skin is pressed on and rubbed, the thicker it becomes. For this reason it is twice as thick in the palms of the hand and on the soles of the feet. Scattered through the true skin are millions of tiny organs fastened to the ends of the nerve threads leading to the spinal cord and brain. These organs tell us when the skin is touched or when it is hot or cold or is being hurt. =The Pores and the Sweat Glands.=--On a warm day the skin becomes wet with a salty fluid called _sweat_ or _perspiration_. This flows from the tiny holes or pores in the skin. A good magnifying glass will show these pores arranged in rows on the ridges in the palm of the hand. From each pore a tube leads down into the true skin to a coiled tube forming the _sweat gland_ (Fig. 45). Sweat glands are present by the thousands in the skin of all parts of the body. They give out from one pint to a gallon of sweat daily. The more we work and the warmer the weather, the more the sweat flows. There is a little waste matter carried out of the body by the sweat, but its chief use is to cool the body. It does this by passing off in the air and carrying the heat with it. In this way the body is kept from getting too hot in summer. =The Color of the Skin.=--In the African race the color of the skin is black, in the Chinese it is yellowish, while in our race it is nearly white. The different hues are due to a coloring matter called _pigment_. This lies in the deep part of the scarfskin. Going out in the wind and sun causes more pigment to collect, and we say we are tanned. If the pigment collects in spots, it makes freckles. There is no way of removing at once freckles or tan. They usually disappear in the winter. No powders nor any other kind of medicine should be taken to make the skin white and smooth. Such medicines may contain poison and are likely in time to hurt the body. The skin may usually be kept soft and smooth by washing well with soft water and good soap. If it becomes harsh or cracked, a little glycerine rubbed on after each washing may help it. =The Nails and their Care.=--The nails are hardened parts of the epidermis. They are intended to prevent the ends of the fingers from being hurt and to give a neat appearance to the hand. The ends of the nails should never be chewed or torn off, as this makes the fingers blunt and the flesh sore. They should be filed or cut neatly with the scissors so that they do not stick out beyond the ends of the fingers. [Illustration: FIG. 46.--Photograph of hands showing at the right how the nails should appear, and at the left how biting off the nails makes the fingers blunt and sore.] Many boys and some girls spoil the appearance of their nails by letting a line of black dirt remain beneath them. A piece of a stick or a nail cleaner should be passed beneath the nails every time the hands are washed. If the fingers are much soiled, a stiff brush is useful in removing the dirt under the nails. [Illustration: FIG. 47.--A slice through a hair in its sac. Much enlarged.] =The Hair.=--Some hair grows on nearly all parts of the body. It is much thicker on the head than elsewhere. Each hair grows from a little knob at the bottom of a tiny tube in the skin called the _hair sac_ (Fig. 47). If hair is pulled out, another one will grow in its place if the knob at the bottom of the sac is not hurt. One or two _oil glands_ open into each hair sac and give out an oil to keep the scalp and hair soft. No other hair dressing is needed. After thirty or forty years of age the hair begins to turn gray. No medicine will prevent the hair from turning gray, and it is generally unwise to color the hair with a dye. There is poison in some of the mixtures sold to color the hair. =The Care of the Hair.=--When the hair is uncombed, the whole person looks untidy. The hair should be combed carefully every morning and again made tidy before each meal. You should use as little water as possible to moisten the hair. The glands can be made to give out their hair oil by squeezing parts of the scalp between the fingers. The scalp should be well cleansed with soap and warm water every three or four weeks. The hair should be dried quickly with a soft towel and by sitting in the sun or near a stove. One is likely to catch cold by going out of doors when the hair is wet. Hair oils and dandruff cures should not be used unless advised by a physician. Pinching and wrinkling the scalp twice weekly with the fingers makes the blood tubes grow larger and bring more food to the hair. It will also in many persons stop the hair from falling out and prevent dandruff and itching. [Illustration: FIG. 48.--Photographs showing how keeping the hair tidy improves the appearance.] Do not use the hair brush of another person or exchange hats with your companions. Unclean persons and those living or playing much with them often have among their hairs little creatures called _head lice_. They suck blood and cause constant itching. The doctor will tell any one how to get rid of them easily. =Keeping the Skin Clean.=--The amount of dead matter carried out by the sweat on to the skin every day is equal to a mass as large as your thumb. Dust also works through the clothing and sticks fast to the moist skin. For this reason every one should wash the whole body once or twice each week. The feet should be washed oftener as they become more soiled. Many persons take a bath every day. A cold bath taken just after rising in the morning wakes up the nerves, makes the heart work better, and gives health and strength to the whole body. Afterward, the body should be well rubbed with a coarse towel. The bath may be taken by lying in a tub of water or by rubbing the body over quickly with a wet sponge. A hot bath is best for cleansing the skin. A warm bath makes one sleepy and should, therefore, be taken only at bedtime. _The hands should always be well washed before handling food._ Persons neglecting to do this have caused much sickness because of the disease germs on their hands. One hundred and fifty persons were given typhoid fever in one city in Massachusetts by a man who handled milk without washing his hands. Dirt and disease are companions. You must be clean if you would be healthy. =The Kidneys.=--The sweat glands do not take out of the blood one quarter as much waste matter as the kidneys. These are two bodies longer than the finger and more than twice as wide, and having the shape of a bean. One lies on either side of the backbone below the liver. The blood coming to the kidneys is full of waste and dead matter picked up from all parts of the body. This is passed out through the thin walls of the thousands of little blood tubes into the many tiny tubes of the kidneys. [Illustration: FIG. 49.--The blood tubes in a piece of skin as large as the head of a pin.] Water is required to keep the body clean within as well as without. For this reason you should drink more than a quart of water daily. A glass or two of water drunk a half hour before meals cleanses and rouses to action the digestive organs. =Alcohol and the Skin.=--The skin of those who use much beer or whisky often becomes rough, red, and pimply. Any alcoholic drink is likely to injure the skin because it may hinder good digestion. The drunkard has a red nose and a dark-colored skin. This is because alcohol weakens the walls of the blood tubes and lets them become gorged with blood. If a person takes a drink only once in a while, his face becomes red after each drink, and an hour or two later the effect of the alcohol passes off. The blood tubes have squeezed up to their natural size. =Alcohol and the Kidneys.=--Taking several glasses daily of even such weak alcoholic drink as beer often causes the kidneys to become sick. Some of their working parts become changed to fat and some parts become hard. The cells which let the waste matter pass out of the blood get hurt by the poison of the alcohol so that they let some of the food also pass out of the blood. PRACTICAL QUESTIONS 1. Name the two parts of the skin. 2. Give the three uses of the skin. 3. What is a sweat gland? 4. How much sweat is formed daily? 5. Of what use is the sweat? 6. How should the nails be cared for? 7. Tell what care should be given the hair. 8. Why should you not use another person's hair brush? 9. Why should the skin be washed often? 10. Of what use is a cold bath? 11. Why should the hands be well washed before handling food? 12. Why does the drunkard have a red nose? CHAPTER XIII CLOTHING AND HOW TO USE IT =Kinds of Clothing.=--People are beginning to learn that the wearing of the right kind of clothing has much to do with keeping them well. Many persons wear too heavy clothing in winter. Keeping the body too hot makes it weak. Some kinds of clothing are much warmer than others. Some are expensive and others are cheap. Cheap clothes will often serve the same purpose as the more costly ones. If you look at your handkerchief or stockings, you will see that they are made of threads running crosswise to each other. All clothing is made from threads. Some of these are wool, some are linen, a few are silk, and many are cotton. =Woolen Clothing.=--Woolen clothing, such as overcoats and fine cloth dresses and suits, is made from the wool cut from sheep. Enough wool can be sheared from two sheep in one year to make an entire suit of clothes. The raw wool is first twisted into threads and then woven by machines into cloth. [Illustration: FIG. 50.--At the left is a bunch of flax gathered from the field, and on the right is a spool of thread made from the flax and ready to be woven into linen.] =Linen.=--Linen is used in making collars, cuffs, and handkerchiefs. It is made from fine threads taken from the flax plant. On a piece of ground as large as a schoolroom enough flax can be raised to make a half dozen collars. Garments to be worn in warm weather are sometimes made of linen. =Silk.=--Silk is used in making neckties, gloves, ribbons, and dresses. Silk cloth is woven from the cocoons made by silkworms. A silkworm is about as big as your largest finger. It grows to this size from the egg in one month. In three or four days it spins a shell of silk thread completely surrounding itself. This shell is called a _cocoon_. Within this it changes to a moth. [Illustration: FIG. 51.--Photograph of silkworms changing mulberry leaves into silk.] [Illustration: FIG. 52.--These fibers from the lint about the seed of cotton are woven into cotton cloth.] When the cocoons are to be used for silk, the worm is killed by heat as soon as it has woven its home so that it may not change to a moth and eat off some of the silk in getting out. Many thousand worms are needed to get enough silk for a dress. The worms are raised largely in China, Japan, Italy, and France. =Cotton.=--All calico, muslin, and most cheap clothing are made from cotton thread. This is made from the cotton fibers surrounding the seeds of the cotton plant (Fig. 52). The cotton used in this country is raised in the Southern states. Cotton clothing is stronger and wears much longer than silk or wool, but it does not look so well and is not nearly so warm. =The Use of Wraps and Overcoats.=--_Outer wraps and overcoats should never be worn in a warm room or while working hard._ They cause much sweat to form on the body, and as soon as one goes out of doors the sweat begins to pass off. This makes the body feel cold and in some cases leads to a long sickness. When riding in cold weather, extra wraps should be worn. Scarfs and furs should not be worn about the throat except in extreme cold weather. Bundling up the neck and chin is likely to cause sore throat. =Danger from Wet Clothing.=--Many children have caught severe colds leading to serious sickness by wearing wet or damp clothing. Wet clothing causes the heat to pass off from the body quickly, so that it is chilled before we know it. This may be shown by wrapping two bottles of warm water in cloths. Wet one cloth and let the other remain dry. In twenty minutes the bottle with the wet cloth will be cool, but the other one will still be warm. _If your wet clothing cannot be changed at once, keep exercising or throw a heavy coat about you._ =Untidy and Soiled Clothing.=--All boys and girls should learn to keep their clothing as clean as possible. Do not wipe the hands on the clothing, or sit down in the dirt, or let food smear the front of the coat or dress. The sweat is constantly bringing waste matter out of the body. This soils the clothing next to it. On this account clothing to be washed every week or oftener should be worn next to the skin. Very thin cotton underclothing should be worn in summer. Woolen clothes give more warmth for winter. [Illustration: FIG. 53.--Showing how to prevent the shoe from pressing on corns caused by wearing tight shoes or socks roughly darned.] =Shoes.=--Badly fitting shoes cause sore feet and much pain. A shoe that is tight across the toes is sure to cause corns. A _corn_ is a thickened part of the top skin which presses on the more tender part beneath. Soaking the feet in hot water and filing off the top of the corn or using a corn plaster will help it. Shoes should always be a half inch longer than the foot. Waterproof shoes or rubbers should be worn in wet weather. Rubbers should not be worn in the house. =Alcohol and Clothing.=--Many persons think that a drink of whisky will make them warm when taken on a cold day. For this reason whisky is sometimes used when clothing is really needed. The use of whisky or any other alcoholic drink will not make the body warm. It may make one feel warm because it loosens the muscles in the blood tubes of the skin and so lets more blood come to the surface. In this way the body becomes colder because too much blood gets into the skin and is then chilled by the cold air. As alcohol deadens the feeling it may prevent one from feeling cold when the body is really very cold. Too little clothing and too much alcohol have been known to cause men to freeze to death. =Experience in using Alcohol to keep the Body Warm.=--Doctor Hayes, who went as physician with Doctor Kane to explore in the Arctic regions, said that he would never again take alcoholic drink with him on such a trip. He declared alcohol was of no use in helping men to keep warm. He found from actual experience that those who use alcohol cannot endure cold so well as other people. Doctor Carpenter, a well-known physician, tells of a crew of sixty-six men who tried to stay in Hudson Bay all winter. They used some alcoholic drink. Only two of the party lived through the winter. Later another party of twenty-two men passed the winter in the same place. They used no strong drink at any time and as a consequence all but two of them were reported well and strong in the following spring. CHAPTER XIV BREATHING =The Lungs.=--The lungs are two light spongy bodies filling up the greater part of the chest. The heart lies between the lungs. The lungs are formed largely of thousands of thin-walled sacs and two sets of tubes. One set of tubes carries air into and out of the lungs, and the other set is filled with blood. These sacs and tubes are held in place by a loose meshwork of tissue. [Illustration: FIG. 54.--The ribs and front wall of the chest cut away to show the lungs. A piece of one lung is cut off to show the heart. _A_ and _E_, parts of the breastbone; _F_, diaphragm.] =Why we Breathe.=--Breathing means taking air into the lungs and forcing it out. The air is made to go into the lungs in order that a part of it called oxygen may get into the blood. The blood then carries the oxygen to all parts of the body where it can help the organs do their work. [Illustration: FIG. 55.--Photograph of a salamander, showing the gills on either side of the head, which are used in breathing.] The air which comes out of the lungs is not the same as that which goes in. Some of the oxygen has been used up and in its place is a heavier gas named _carbon dioxide_, which has been given out by the body. This carbon dioxide is part of the waste formed in every part of the body from the used-up food and dying parts of the body. We breathe therefore to get oxygen into the body and to take out some of the waste matter. All animals must breathe. If our breath is shut off only four or five minutes, death results. In the earthworm the oxygen goes right through the skin into the blood. Bugs and flies have several little openings along the sides of the body which lead into tubes branching throughout the body to carry air. A fish gets air through its gills lying under a bony flap on each side of the head. [Illustration: FIG. 56.--The windpipe and lungs viewed from in front. On the right, the tissue is removed to show the air tubes.] =How the Air passes into the Lungs.=--The outer openings of the nose are called nostrils. From here two channels lead back through the nose to the throat. The cavity of the throat behind the nose and tongue is the _pharynx_. At the bottom of the pharynx is a tube made mostly of gristle. This tube is larger than your thumb and is named the _larynx_, or _voice box_. The bump on its front part forms the lump in the throat called the _Adam's Apple_. From the voice box extends the _windpipe_ called _trachea_, down to the lungs. The windpipe divides at its lower end between the lungs into two branches. One of these enters each lung. =The Air Tubes in the Lungs.=--As the branch of the windpipe enters each lung it divides into smaller branches just like the limbs of a tree. These divide into still smaller tubes, which branch again and again until they are as small as a hair. These hairlike tubes have swollen ends called _air sacs_. The walls of the air sacs are much thinner than tissue paper. [Illustration: FIG. 57.--A bunch of air cells at the end of an air tube in the lungs, showing the blood vessels which receive the oxygen and give out the carbon dioxide.] =How the Blood trades Waste for Oxygen in the Lungs.=--The blood, which is constantly running from all parts of the body to the lungs, collects waste formed from the burnt food and dying parts of the organs. When the blood comes to the lungs, it is full of this waste, called carbon dioxide. The blood tubes divide into fine branches with very thin walls and form a rich network over the air sacs. This allows the carbon dioxide and water to pass out of the blood tubes into the air sacs, while the oxygen at the same time goes through into the blood. More than a pint of water is given off in the breath daily. =How we Breathe.=--The bottom of the chest cavity is formed by an upward arching sheet of muscle called the _diaphragm_. This is fastened to the lower ribs. The ribs at rest slant downward and inward. When the ribs are pulled up or the arch of the diaphragm down, the cavity of the chest becomes larger. The air then runs into the lungs and swells them out. When the ribs are let drop or the arch of the diaphragm goes up, the air is pushed out of the lungs. Without thinking, we work the muscles to draw up the ribs about eighteen times every minute, because all parts of the body are calling for oxygen. The harder we work the oftener we breathe because the muscles need more oxygen to make them go. =Why we should breathe through the Nose.=--Most persons find it easy to breathe through the nose. In some, however, the passages in the nose are too small to carry the air without effort. On this account they let the mouth hang open and breathe through it. [Illustration: FIG. 58.--Face cut through the middle to show how the adenoids stop the air from passing through the nose. Arrows show the course which the air should take.] The air should pass only through the nose because it is lined with hairs and tiny waving threads which catch the dust. In this way germs and dirt are prevented from getting into the throat and lungs, and in winter the cold air is warmed. =Why Some Children cannot breathe through the Nose.=--When one has a cold, the lining of the nose becomes swollen and gives out a white substance called _mucus_. The swelling of the lining and the mucus fill up the passages. The nose should be kept clean by using a handkerchief and blowing out the mucus into it. _Never put the finger into the nose._ Disease germs often get on the fingers from things touched. Children who have the habit of breathing through the mouth should be examined by a physician. He will, in most cases, find soft spongy growths called _adenoids_ in the back part of the nose. They should always be removed as soon as possible. They may cause disease or deafness and may even injure the mind. [Illustration: FIG. 59.--A view of the voice box from the top.] =The Voice.=--In the upper part of the voice box at the top of the windpipe is a fold of tissue stretched on either side. These two folds of tissue form the _vocal cords_. The air rushing past them causes sound. The different sounds are made by stretching the cords tight or loosely. By means of the tongue, teeth, and lips the sound is formed into words. =How to use the Voice.=--A cold or much shouting makes the vocal cords swell and we become hoarse. Rest is the best cure. It is not polite to shout or whistle in the house and you should never use an angry tone of voice. When talking to a person, always speak distinctly but pleasantly and turn your face toward his and look directly into his eyes. Never use a harsh, loud tone of voice. =Why you should not spit on Floors or Sidewalks.=--We used to think that any one well had no germs of sickness in his mouth, but we now know that many well persons have germs in their mouths which can cause long sickness when they get into other persons. If you are sick with diphtheria, scarlet fever, or sore throat, the germs of the disease are likely to remain in your mouth two or three months. Persons with tuberculosis throw out millions of these germs in their spit every day. Spitting is not only an unclean habit but a deadly curse. Spit often contains the seeds of death. Women's skirts and the soles of our shoes carry it into the houses. It becomes dry, but the germs live and float about in the dust, then enter the mouth to make us sick. Carelessness with spit is said to cause more than a hundred deaths every day in our land. =Do not use an Open Spittoon.=--It is much safer to have a smallpox patient in the house than an open spittoon in the summer. You can prevent the smallpox by vaccination, but you cannot keep the flies from carrying ten thousand germs of death from the spittoon to the food on the table. A million germs have been found on a single fly. [Illustration: FIG. 60.--Photograph of a house fly on a piece of bread. This fly had been feeding on spit and a study of its legs and body showed more germs present than there are hairs on a person's head.] Spit should be dropped into a cup which should be kept covered when not being used. The spit should be destroyed by fire or some germ-killing fluid, such as lye or formalin. [Illustration: FIG. 61.--An exact drawing of the germs in a spot as large as a period, on the edge of a drinking cup.] =Keeping Sickness away from the Throat and Lungs.=--All sickness of the throat and lungs is caught from some one else. The germs are passed from one to another on the drinking cup, by sucking pencils, wetting the finger to turn the pages of a book, or putting the fingers in the nose or mouth. [Illustration: FIG. 62.--A dish of beef broth jelly left open two minutes in a room being swept. Each spot is a city of thousands of germs which grew from one germ dropping on the jelly. By counting the spots you can tell how many germs fell from the dust on this dish three inches in diameter.] _Dust is the partner of disease._ It contains germs. Avoid dust. Wipe up the rooms with a damp cloth; never use a feather duster. Avoid dry sweeping. Use a suction cleaner or have rugs which can be cleaned out of doors. Give the lungs fresh air and deep breathing and the body good food and plenty of sleep to make it so strong that germs cannot overcome it when they enter. [Illustration: FIG. 63.--Photograph of consumption germs, the tiny rods which often grow and cause tuberculosis in bodies weakened by beer or whisky. Much enlarged.] =Alcoholic Drink and the Lungs.=--The most common disease of the lungs is _tuberculosis_. Nearly all bartenders who sell strong drink take some themselves. Lately it has been learned in Germany that tuberculosis causes one half of all the deaths among bartenders. Alcohol was once thought to be a good medicine for lung troubles, but it has been clearly proven that beer and whisky weaken the lungs and make them ready for the germs of disease. The body already weakened by the poison of the alcohol is then easily overcome by the disease. =Tobacco and the Lungs.=--The occasional use of tobacco does not seem to hurt the lungs when fully grown. A study of many young persons has shown that the chest of smokers grows much more slowly than in those who do not use tobacco. As the lungs cannot grow any faster than the chest, they must grow slowly in boys using much tobacco. Tobacco is a common cause of sore throat. Many smokers have been compelled to quit the habit because of throat troubles. PRACTICAL QUESTIONS 1. Where are the lungs located? 2. What do the tubes in the lungs carry? 3. What part of the air do we use in the body? 4. Tell how the air gets into the lungs. 5. What passes from the blood into the air sacs? 6. Why should we breathe through the nose? 7. Why should you keep the fingers away from the nose? 8. What are the vocal cords? 9. Give two reasons why no one should spit on the floor. 10. Tell how alcohol harms the lungs. CHAPTER XV FRESH AIR AND HEALTH =How much Air we Breathe.=--At every breath we take in about one pint of air. We breathe eighteen times each minute. Nine quarts of air therefore pass in and out of the lungs every minute. Air once breathed is not fit to breathe again. It contains waste and carbon dioxide which weaken the body. If you breathe three full breaths into a wide-mouthed jar or bottle, it will contain so much of the carbon dioxide that a lighted candle or splinter will at once go out when thrust into the jar. A cat shut in a tight box two feet square and one foot high will die in less than a half hour. Many years ago when the British and Hindoo soldiers were fighting each other, the Hindoos made prisoners of 146 of the British and locked them in a room about one half as large as a common schoolroom. There were only two small windows. During the night 123 of these men died because of the bad air. [Illustration: FIG. 64.--The direction of the flame of the candle shows how the fresh air enters and the bad air leaves a room.] =How much Air should enter a Room.=--The air laden with waste coming out of the lungs quickly mixes with the other air of the room. In this way all of the air in the room soon becomes impure. Forty children will give out nearly two barrels of air in one minute. In another minute this air has made all of the other air in the room unclean. It can still be breathed, but it makes children feel drowsy and lazy and may cause headache. They then do poor work. To keep the air pure in a room, fresh air must be let in from the outside. If there are many in the room, the openings must be large or fans on a wheel must be used to force the air in. In the New York schools a little over a cubic yard of fresh air is forced into the room for each child every minute. =How to get Fresh Air into a Room.=--When air is warmed it becomes lighter and rises. In many public buildings, fresh air heated by a furnace is forced into the rooms through pipes entering several feet above the floor. By a fan or heated flue the impure air is sucked out of the room through openings near the floor. [Illustration: FIG. 65.--How the windows of your bedroom should be open to get the most fresh air.] Changing the air in a room is called _ventilation_. To get plenty of fresh air in a room there must be one or more places for it to enter and one or more places for it to pass out. Where there is no furnace or fan, windows on one side of the room may be opened at the bottom to let in the air and the same windows opened at the top to let the impure air escape. _Do not sit in a draft_, but use a board or curtain to throw the air upward as it enters the window. _A room should not be kept too warm._ Sitting in a very warm room weakens the body and prepares it to take cold. The temperature of a living room should be between 65 and 70 degrees. =Fresh Air while you Sleep.=--Thousands of people have weakened their bodies and brought on disease by sleeping in bad air. Many persons keep their windows so tightly closed during the night that the air smells bad in the morning. I knew a family who always slept with windows closed except in the very warmest weather. Three of the children died of tuberculosis, and a fourth one took the disease but was saved by keeping his windows wide open. Bad air in the sleeping room makes one feel drowsy in the morning instead of refreshed by sleep. _Your windows should always be open while you sleep._ In cold weather a window should be open a foot at both the bottom and the top, or if there are two windows in the room, both may be opened at the bottom. In moderate weather the openings should be twice as large. A cap may be worn to keep the head warm, and the bed should be out of the draft. =Fresh Air gives Health.=--Four hundred people die of tuberculosis in our country every day. A few years ago it was thought that no one could get well of this disease. Now three fourths of those in the first stages of the disease get well. The chief part of the cure is fresh air. Medicine is seldom used because no medicine will cure tuberculosis. Good food and rest are great helps. Many of those with tuberculosis stay out of doors all day and at night sleep in tents or with all of the windows wide open, even in the coldest weather. Snow may blow in and the water in the room may turn to solid ice, but fresh air, the good angel of health, will give the body new strength and make it well and strong again. [Illustration: FIG. 66.--This man is curing himself of tuberculosis by sleeping at night, and sitting by day, on this porch.] Many years ago when the Indians lived in tents and often slept outdoors none of them had this dirty air disease of tuberculosis. Since they have formed the habit of living in houses nearly one half of some tribes have become sick with this catching disease. =Making the Lungs Strong.=--It requires over three quarts of air to fill your lungs. When you breathe quietly, less than one pint of air passes in and out of your lungs. This shows that a large part of the lungs is not used. The air sacs at the top and in the bottom part of the lungs are seldom filled completely. It is in these places that disease begins. Several minutes should be spent two or three times each day in exercising the lungs. Fill them completely with air many times. _Learn to breathe deeply while you are walking in the fresh air._ Hold the head up and the shoulders back so that every part of the lungs can be filled. _Sit straight. Your life depends upon your lungs._ Give them a chance to do their work and teach them to do it well. [Illustration: FIG. 67.--Unhealthful position which squeezes the lungs so that they cannot work freely.] =Tobacco and Pure Air.=--There is poison in the smoke of tobacco. This is shown by its effect on insects. Owners of greenhouses often buy the stems and other waste parts of tobacco. They pile it in a pan and after closing the doors and windows of the greenhouse tightly, set fire to it. The smoke rises and fills the whole house. In less than an hour it has killed many of the bugs and beetles which were destroying the plants. A person not used to tobacco will sometimes be made sick by sitting only an hour in a room where persons are smoking. It is wrong for smokers to poison the air which others must breathe. For this reason a smoking room should be well ventilated. CHAPTER XVI THE BLOOD AND HOW IT FLOWS THROUGH THE BODY [Illustration: FIG. 68.--The cells in the blood. The two white ones were drawn while crawling. Much enlarged.] =The Blood keeps the Body Clean within and gives it Food.=--Every tiny particle of the body, whether in the legs, arms, or head, must have food to keep it alive and help it do its work. It must also have oxygen, and it must be washed clean of its waste matter. All this is done by the streams of blood, which bathe every cell to bring it food and oxygen and to wash away its waste. =Parts of the Blood.=--Blood consists of a clear, watery part called _plasma_ and many little bodies named _cells_. The liquid found in a blister is the clear part of the blood. The cells which float in the watery part are so little and so close together that more than a million are in each drop of blood. A few of the cells are white, but most of them are red, and it is their color that makes the blood look red. Your body contains about one gallon of blood. It is carried through the body in branching tubes called _blood vessels_ (Fig. 70). [Illustration: FIG. 69.--Photograph of the heart from in front with the lungs pinned aside. One fourth natural size.] =The Blood Vessels.=--There are four kinds of blood vessels. They are the _heart_, the _arteries_, the _capillaries_, and the _veins_. The heart lies in the chest between the lungs. It squeezes the blood into the arteries. These carry the blood to all parts of the body. It then runs into the capillaries, which are tiny tubes connecting the arteries with the veins. The veins return the blood to the heart. The blood flows so fast that it goes from the heart down to the toes and back again in a half minute. =The Heart or Pump of Life.=--When the heart stops we die, because the blood can no longer flow to carry food and oxygen to the hungry tissues. The heart is a sac with thick walls of muscle. It is shaped like a strawberry and is about as large as your fist. Its cavity is divided into four parts. The two upper ones are called _auricles_ and the lower ones are named _ventricles_. The blood enters the auricles and then pours through an opening into each ventricle, from which it passes out into the arteries. =The Arteries or Sending Tubes.=--The blood is sent out from the heart through the arteries leading to all parts of the body. The chief artery is the _aorta_. It is larger than your thumb and extends from the heart down through the body in front of the backbone. It has more than twenty branches. All of these branch again and again like the limbs of a tree until they are finer than hairs. A large tube, the _lung artery_, takes blood directly from the heart to the lungs. Here it branches into more than a thousand divisions, so that the blood can take in oxygen and give off to the lungs its waste. [Illustration: FIG. 70.--Arteries, the tubes carrying the blood from the heart through the body. Only the chief vessels are shown on one side.] =The Capillaries or Feeding Tubes.=--These are the tiny tubes, finer than hairs, which join the smallest end branches of the arteries with the beginnings of the little veins. They are so thickly scattered in the flesh that you cannot stick it with a pin without piercing one. They are called feeding tubes because they have such very thin walls that the food in the blood and the oxygen brought from the lungs can pass through to feed the muscles and other organs. The dead parts of the body and also the ashes of the food used up, pass from the organs into the capillaries. =The Veins or Returning Tubes.=--The veins, beginning in fine branches formed by the capillaries, return the blood to the heart. The branches unite into larger and larger vessels and finally flow into one main vein, the _vena cava_. This extends along in front of the backbone and opens into the heart. =Why the Blood flows in only one Direction.=--The heart causes the flow of the blood. It does this by squeezing together its walls so as to make the blood go out into the arteries. When once in the arteries, the blood must go forward because there are little doors at the mouths of the arteries in the heart. These doors, called _valves_, open in only one direction, so that the blood cannot flow backward (Fig. 71). There are other valves between the upper and lower cavities of the heart, preventing the blood from being pushed back into the veins. [Illustration: FIG. 71.--The heart with the front part cut away to show the four chambers and valves. The arrows show the direction in which the blood flows.] The movement of the walls of the heart in and out is called the _heart beat_. This can be plainly felt by placing the hand on the left side of the chest. The heart beats about seventy times each minute in grown persons, but much oftener in children. At each beat a wave of blood flows along the arteries. This is known as the _pulse_. It may be felt at the base of the thumb, where an artery runs just under the skin. =Why the Heart sometimes beats Faster.=--When we run or do hard work, the heart may beat twice as fast as when we are lying down. This is because the muscles need more oxygen to help them act. Work makes them get hungry, and they send word by the nerves to the heart to hurry along the blood to bring more oxygen from the lungs. When germs make the body sick, the heart often beats faster because it is affected by the poison made by the germs. The doctor then feels the pulse to tell how much the body is poisoned. =Use of Blood Cells.=--The red cells act like boats. They load up with oxygen in the lungs and carry it to all parts of the body. Here they trade it off for carbon dioxide, a waste substance. This they carry back to the lungs to be cast out of the body. There is one white blood cell to every four hundred red ones. The white cells are the body-guards. They change their shape and are able to crawl through the walls of the capillaries. Wherever the body is hurt, they collect in large numbers and eat the germs which are always trying to get into the body through sores. The white matter called _pus_ in a sore is largely made of white blood cells which came there to fight the germs and were killed in the battle. The germs of boils and fevers often get into the blood, but the white cells usually kill them before they have a chance to grow into large numbers and make the body sick. =How to stop Bleeding.=--Most of the larger arteries are deep in the flesh and seldom get cut. There are many veins just under the skin. If the blood comes out in spurts, it is from an artery; but if it flows steadily, it is from a vein. If the blood does not run out in a stream, it will stop without any special care. As soon as the blood gets to the air it forms a jellylike mass called a _clot_. This helps stop the flow. All hurt places in the skin should be tied up in a clean cloth. [Illustration: FIG. 72.--Stopping the flow of blood from an artery.] If a large artery is cut, a bandage twisted tight with a stick around the limb on the side of the wound next to the heart will stop the bleeding. If a vein is cut, the bandage should be placed on the side of the cut away from the heart. =Alcoholic Drinks weaken the Blood.=--It has been noticed for some years that when a user of beer or whisky is attacked with fever, the disease is more severe than in one not using alcohol. The reason for this has lately been explained by a well-known scientist working in Paris. He put certain disease germs in rabbits, but they did not become sick. When he gave them a little alcohol and put the same amount of disease germs in them as before, they became sick and died. By careful study he learned that the white blood cells had in the first case killed the germs. In the second experiment the blood cells were made so weak and lazy by the alcohol that they did not put up such a strong fight against the germs. =Tobacco and the Blood.=--Any one who chews or smokes tobacco regularly gets much of the poison into the blood. The vessels in the mouth and throat drink in some of the juice and also the poison from the smoke. How much this poison affects the blood cells is not known, but it is likely to do them some harm because it makes the growing cells of the body less active. =How Beer weakens the Heart.=--Whisky was at one time thought to strengthen the heart, but doctors generally agree now that it weakens the heart. It may make the heart beat a little stronger for a few minutes, but after that the beating is weaker than usual. Much use of beer is known to make fat collect around the heart and also cause some of the heart muscle itself to change into fat. In this way the heart becomes so weak that it can no longer do its work, and death results. The reports from Germany show that hundreds of persons die every year from weakened hearts made so by the use of much beer. =Alcohol hurts the Blood Vessels.=--Careful examination of the blood vessels of drunkards after death shows that in many cases the alcohol has caused the walls of the vessels to become thick and sometimes hard. The thickening of the wall makes the channel of the tube smaller. The heart must then work much harder to get the blood through to feed the tissues. =Tobacco and the Heart.=--Many boys who use tobacco regularly do not have a steady heart beat. This is specially true of those who smoke several cigarettes daily. A few years ago, when our country was at war with Spain, thousands of young men, wanted for soldiers, were examined to find out whether their bodies were strong enough to endure the hardships of war. Hundreds were refused admittance to the army because of weak bodies, and many of them were reported by the physicians as having hearts weakened by the use of tobacco. The boys preparing for the army at the Military Academy at West Point and for sea fighting at the Naval Academy at Annapolis are not allowed to smoke cigarettes. Our country must have strong men for hard work. Tobacco never gives strength, but often causes weakness. CHAPTER XVII INSECTS AND HEALTH =Malaria or Chills and Fever.=--Malaria is a disease in which the patient usually has a chill followed by a fever at the same time each day or every other day. Thousands of people suffer from this sickness in the warm parts of our country and hundreds of them die every year. In some regions people cannot live because this sickness attacks every one who comes there. Many years ago a doctor found in the blood of malaria patients tiny animals. He thought that they might be the cause of the illness, but he could not find out how they got into the blood. =Finding out how Malaria Germs get into the Blood.=--It had been noticed for many years that mosquitoes were always found wherever there was malaria. In the year 1900 two men decided to find out if they could live in a malaria region and not have the disease when the mosquitoes were kept from biting them. [Illustration: FIG. 73.--Position of the common humpback mosquito at rest with body full of blood sucked by thrusting the bill into the flesh.] They made their home a whole season in a cottage in the midst of many persons who were sick with malaria. They breathed the same air, ate the same kind of food, and drank the same kind of water as those who suffered from the disease, but they remained well. The only thing that they did different from those who got sick was to keep the mosquitoes out of their rooms at night by means of screens. This experiment and many other studies have shown that we catch malaria only by the bites of mosquitoes. [Illustration: FIG. 74.--Position of the malaria mosquito at rest.] =Only a Few Mosquitoes carry Malaria.=--Malaria is not common in all regions where mosquitoes live, and it has been found that only one group of mosquitoes carries the germs. The two common groups are the straight-backed and the humped. To prove that the straight-backed ones did the harm several of them were allowed to suck blood from a man sick with malaria in Italy. They were then sent to London and let bite a healthy man. In a few days he became sick with malaria. Many experiments with the humped-back mosquitoes, found nearly everywhere in our country, show that they do not carry malaria germs. =Yellow Fever.=--Until 1901 yellow fever was the scourge of many cities in the South. Thousands of persons lost their lives from it. Wherever the dread disease broke out in a city many persons would flee to the country because they thought that they could not breathe the air without getting the germs. Some persons thought that mosquitoes might cause the disease, and in 1900 experiments were carried out in Cuba to learn whether mosquitoes really did carry yellow fever germs. Seven men made their home in a room well screened to keep out the mosquitoes. They used clothing which had been worn by others sick with the fever and even slept on pillows and blankets on which yellow fever victims had died. Many persons thought that these bedclothes were full of fever germs and that all the men would surely get the disease. Not one of them, however, got sick although they lived in the midst of these soiled materials for three weeks. [Illustration: FIG. 75.--The yellow fever mosquito biting the finger. Note how the lower lip is bent.] Seven other men were chosen for another experiment. A large room was prepared and made thoroughly clean. Only clean bedding and clean clothes were used. The men were given pure food and pure water, but into the room were let loose mosquitoes which had been sucking blood from a person sick with the fever. In a few days six of the seven men became sick with the fever and one of them died. From these experiments and other studies we now know that _this dreadful fever is carried from the sick to the well only by the bites of mosquitoes_. [Illustration: FIG. 76.--A bunch of mosquito eggs floating on the surface of the water. Enlarged about fifteen times.] =How Mosquitoes Live.=--Before we can get rid of any pests we must know where the eggs are hatched and the young pass their early life. The eggs of mosquitoes are laid on standing water. The water may be in an old tomato can, a rain barrel, a cistern, or a large pond. A day or two after the mother lays one or two hundred eggs, they hatch into dark, wriggling objects called _wigglers_. In from ten to twenty days later they change into flying mosquitoes. These habits of life show that the easiest time to kill them is when they are young. [Illustration: FIG. 77.--Photograph of wigglers, the stage in which the mosquito lives a week or two in water.] =Getting rid of Mosquitoes.=--During warm weather mosquitoes cause the death of more than a thousand persons in the world every day besides making many others very sick. To get rid of mosquitoes is to prevent sickness and death. In one year yellow fever killed over five thousand people in New York and Philadelphia because the doctors did not know how to stop the disease from spreading. When this fever broke out in New Orleans in 1905, less than five hundred persons died of it because the doctors had then learned that the disease is spread only by the yellow fever mosquito. They therefore began killing the mosquitoes. Kerosene was poured over all the ponds and stagnant pools of water which could not be drained. This kills the young mosquitoes because the oil gets into their breathing tube which they stick up to the surface of the water to get air. All rain barrels and tin cans were emptied and cisterns were tightly covered. Men, women, and children worked week days and Sundays killing mosquitoes because they knew that they were saving human life. The destroying fever was stopped. [Illustration: FIG. 78.--Photograph of eggs laid on waste matter by two flies in one hour.] =Flies cause much Sickness.=--Very few people are afraid of house flies because they do not bite. Although they are so small and seemingly harmless yet we know that they cause many more deaths every year than mad dogs, poisonous snakes, and all wild beasts. Flies crawl around among slops, in spittoons, and in other unclean places. In this way they get thousands of germs of tuberculosis, typhoid fever, and cholera on their feet and then scatter them over our food as they crawl about on the table, in the grocery store, or among the milk cans. In our last war with Spain more than a thousand of our soldiers were made sick with fever carried to them by flies. In Denver, Colorado, in 1908 fifty persons were made sick with the fever by flies which fed on the slops from a sick room and then crawled around in the milk cans from which those who became sick used milk. [Illustration: FIG. 79.--Photograph of the worm stage or larva of the fly at the left and three of the sleeping stage or pupæ at the right. Twice the natural size.] =How to fight the Flies.=--House flies lay at one time about one hundred eggs in the dirt thrown out of horse stables, in garbage cans, or in any other unclean place. In a day or two the eggs hatch into little white worms which feed on the dirt. One or two weeks later the worms change to flies. Flies may be kept out of houses by putting screens in the windows and doors or by darkening the rooms when they are not in use. The few which gain entrance may be caught in fly traps. All food in the store or the home should be kept covered. It is not safe to eat candy on which flies have wiped their feet or to drink the milk in which they have washed them. [Illustration: FIG. 80.--Photograph of a half handful of manure which had been thrown out of a horse stable. Note more than one hundred houseflies in the sleeping stage.] The surest way to get rid of flies in any community is for all the people to work together and keep the entire neighborhood clean. No dead grass, weeds, or rags should be allowed to lie in the backyards or alleys. The cleanings from stables should be hauled away every week or stored in tightly covered boxes. Garbage cans must have close-fitting lids, so that there will be no place in which the young may hatch and grow. =Other Insects which carry Disease.=--In certain parts of Africa, the _sleeping sickness_ has made ruins of prosperous villages. Thousands of the natives are dying yearly from this disease. The germs are carried from one person to another by the bite of a fly. Some fleas carry the germs of _plague_, which a few centuries ago swept across Asia and Europe destroying hundreds of lives daily. The plague is now common in India and was present in California in 1908 and 1910. The bedbug spreads several kinds of fevers in warm countries and may also be a carrier of leprosy and typhoid fever. These facts show that insects are dangerous and should be kept out of the home. Any one troubled with these little pests in the house may learn how to get rid of them by writing to the Department of Agriculture, Washington, D.C. CHAPTER XVIII HOW THE BODY MOVES =The Need of a Framework.=--The body needs a stiff framework made of bones for three purposes. One purpose is to give it shape, a second purpose is to help the body move, and a third one is to protect from injury some of the delicate organs, such as the heart and brain. The bones are nowhere separate but are joined together with tough bands named _ligaments_. All the bones together form the _skeleton_. All animals from fish to man have a skeleton. Many of the lower creatures, such as worms and flies, have no bony skeleton. Most of these move sluggishly or have a hardened outer covering, like beetles and wasps. The skeleton of animals such as the cat, rabbit, or cow, has about the same number of bones as man, and they are arranged in the same way. =Of what a Bone is Made.=--Although the bones are so hard, they are not dead. They contain blood, have feeling, and are just as much alive as the softer parts of the body. It is the lime that makes them stiff. This can be eaten out by putting the bone in strong vinegar or other acid for a few days. A long bone will then become so limber that it can be tied into a knot. The living part of a bone can be burned out by placing it on hot coals for a half hour. At the end of this time the bone will look just as before, but when it is touched, will crumble to pieces. =Forms of Bones.=--The bones of the legs and arms are hollow. This form gives the greatest strength with the least weight. You can prove this by using two sheets of paper. Roll one sheet and fold the other one. Hang weights on both ends of each and use the finger for a support in the middle. The cavity of these bones is filled with a soft white substance called _marrow_. This is largely fat. Each bone is surrounded by a tough membrane to which the muscles are attached. =Arrangement of the Bones.=--The bones of the head form the _skull_. The other bones of the body not belonging to the _limbs_ make up the _trunk_. There are over two hundred bones in the entire body. Eight of these form a case for the brain. Fourteen give shape to the face. A chain of twenty-six bones named _vertebræ_ forms the backbone. [Illustration: FIG. 81.--Photograph of the bones of the skeleton.] Twelve pairs of _ribs_ encircle the chest. They are fastened behind to the backbone. The front parts of the ribs are made of pieces of gristle. The seven upper pairs are joined to the breastbone. The five lower pairs are named _false ribs_. The _collar bone_ is in front of the shoulder and behind it is the flat _shoulder blade_. There is one bone in the upper part of each arm and leg and two bones in the lower part of each limb. Twenty-eight small bones are found in the hand, while twenty-seven are present in the foot. =How the Bones may be Injured.=--In the young some of the entire bones and parts of many others are soft like gristle. For this reason, the bones of the young seldom get broken, but they are easily bent and pressed out of their natural shape. On this account you should hold the body erect in sitting and walking. Bending over the table or desk day after day is not only likely to cause round shoulders, but is sure to squeeze up the lungs and other organs so they cannot do their best work. Sitting at a table or desk, so that one shoulder is higher than the other or carrying books at the side, so that they rest on the hip may cause a curve sidewise in the backbone. Tight clothing about the waist presses the ribs out of shape and hurts the other organs within the body. [Illustration: FIG. 82.--How the bones are held together. A piece has been cut out of the tough ligament to show the cup of the hip bone into which the head of the thigh bone fits.] =Caring for Broken Bones.=--When a bone of the arm or leg is broken, the muscles tend to make the ends shove over each other. The broken ends are sometimes sharp, and if the limb is bent, these may tear through the flesh. This may be prevented by binding a board firmly on opposite sides of the limb across the broken part. This will hold the bones in place until the surgeon comes and will also allow the patient to be moved. The surgeon will set the broken bones by bringing the ends together and holding them in place by sheets of wood or metal firmly held by a bandage. In a few days the membrane around the bone begins to grow new bone to join the broken parts. =How the Bones are joined together.=--The two general classes of joints are the _movable_ and _immovable_. Except the lower jaw, the bones of the skull are so tightly joined together that there is no motion between them. The bones of the wrist and back have but little movement. The freest motion is at the shoulder joint, where the round head of one bone fits into the shallow cup of another. This is called a _ball and socket joint_. Such a joint is found also at the hip. At the elbow and knee the bones move back and forth like a hinge and these are named _hinge joints_. =Working Parts of a Joint.=--The ends of the bones are covered with a thin layer of gristle. The bones are held in place by several strong bands called _ligaments_ (Fig. 82). These entirely surround the joint. On their inner sides is a delicate membrane which gives out a slippery fluid to make the joint work easily. The ligaments are sometimes strained, stretched, or torn by a fall. The joint then swells because the watery part of the blood collects there. A sprained limb should be elevated to prevent swelling. Bathing it in very hot water is helpful. =The Muscles.=--The muscles form the lean meat in any animal. They make up about one half the weight of the body. Each muscle is a bundle of thousands of little threads held together by other finer threads, while the whole is surrounded by a thin sheet. Little bundles formed of several of these threads called fibers may be seen in a piece of cooked beef picked to pieces. There are over five hundred muscles in the body. [Illustration: FIG. 83.--Fifty of the muscles just under the skin. Note the white cords, the tendons in the regions of the hands and feet.] [Illustration: FIG. 84.--The biceps muscle contracted above and relaxed or loosened below.] Some of the muscles are more than a foot long and have the shape of a ribbon. Some are circular like those around the mouth, eyes, and stomach, while others are large in the middle and taper toward the ends. =How the Muscles are fastened to the Bones.=--The two ends of a muscle are attached to different bones. In many cases the muscle is not joined directly to the bone, but is connected to a tough white cord called a _tendon_. The tendon is then fixed to the bone. Several of the muscles in the forearm run into tendons in the wrist because if the muscle part were to extend along the wrist, this part of the arm would be large and clumsy instead of graceful and slender. Some of these tendons may be seen to move by bending the wrist and then working the fingers. =How the Muscles do their Work.=--A tiny nerve thread runs from the spinal cord or brain to every muscle thread. Messages sent through the nerve threads to the muscles make them act. A muscle can act in only two ways (Fig. 84). It can become shorter or longer. When it gets shorter, we say it _contracts_. When it stretches out, it is said to _relax_. A muscle cannot contract more than one fourth of its length. To pull the forearm up, the brain sends a message to the muscle fixed by one end at the shoulder and by the other end to a bone at the elbow. The muscle at once becomes shorter and thicker, as may be felt by placing the fingers on it. Although it shortens only two inches it is fastened to the bone so near the elbow that it draws the hand up two feet. PRACTICAL QUESTIONS 1. Of what use are the bones? 2. What animals have bony skeletons? 3. What can you say of the form of bones? 4. How many bones in the body? 5. Name six bones. 6. What part of the arm has two bones side by side? 7. How many ribs have you? 8. Explain how a broken bone should be cared for. 9. Point out and name two kinds of joints. 10. What are ligaments? 11. Of what is a muscle made? 12. How many muscles in the body? 13. How many tendons can you feel in your wrist? CHAPTER XIX THE MUSCLES AND HEALTH =Making the Muscles Strong.=--No persons use all of the five hundred muscles in the body every day. In slow walking only about twenty muscles are used, while in running more than four times that number are called into action. Muscles which are not used get lazy and weak. Every time a muscle is made to act the blood vessels enlarge and bring to it more blood to supply food. The more food the muscle has the stronger it grows. The right arm is used more than the left in most persons. This makes it so much stronger that some boys can lift twenty-five pounds more with the right arm than they can with the left. =Using the Muscles keeps the Body Well.=--All muscles must have more blood when they are used so that the heart is made to beat faster and stronger by exercise. In this way its valves and walls become able to do more work. Such a heart not only does its work better in a well person, but is able to keep pumping when the body is weakened by disease. Many persons die because the heart gets too weak to push the blood through the body. In all the little spaces between the muscles and parts of other organs is some watery part of the blood containing much waste given off from the tissues. Moving the muscles presses on this watery waste in such a way as to move it along into the blood channels. It then can be cast out of the body by the lungs and other organs. One reason why we feel so good after exercise is because the poisonous waste has been taken away. No one can remain well very long without taking exercise. Children as well as older persons should enjoy one or two hours of outdoor play every day. [Illustration: FIG. 85.--Various ways of exercising the muscles to keep the body well.] =How to exercise the Muscles.=--Outdoor games give the best form of exercise. Tennis, baseball, cricket, rowing, and swimming are sports which bring nearly all the muscles into use. Every boy and girl should learn to swim. It is dangerous to go swimming alone or to swim in deep water. Cramp may seize the muscles at any time, so that the limbs cannot be moved. Hundreds of persons are drowned every year by venturing in deep water. Taking care of the yard and garden and helping with other work about the home is one of the best ways of getting exercise and at the same time doing some good. =Special Kinds of Exercise.=--A room with ropes, swings, and machines in it for exercise is called a _gymnasium_. Under the direction of a teacher the pupils can get quickly just the right kind of exercise to strengthen the weak parts of the body and keep every organ in health. The muscles oftenest neglected are those of the chest. Every one should keep his chest full and round by swinging the arms and _practicing deep breathing every day_. =Danger from too much Exercise.=--Lately it has been learned that very violent exercise for more than a few minutes often injures the heart. The running of many races until you are all out of breath or much jumping of the rope is likely to strain the heart. It is always harmful to urge the body on until it is completely tired out. =Alcohol makes the Muscles Weak.=--In the year 1903 two learned men in Switzerland spent much time to determine whether alcohol helped persons do more work. They tried more than two hundred experiments with men to whom they sometimes gave wine and sometimes food, and sometimes both were given together. The results of these tests showed that when wine was given alone, the man's ability to do work was increased for a short time, but later he could not do so much work as when he had taken no wine. When the man took both food and wine, he could do only about nine tenths as much work as when he took food alone. The most careful tests by other persons show that whisky will not help a man do more work, lift a heavier weight, or shoot straighter. In fact little or much whisky makes him less able to do any of these things. =Beer makes the Muscles Lazy.=--Doctor Parkes of Netley secured two gangs of soldiers to do the same kind of work. He allowed the first gang to drink some beer, but the second gang were not allowed to have any. During the first hour the beer gang did the most work, but after that the temperance gang did far more work during the entire day. The next week beer was refused the first gang and given to the second. The beer helped the second gang do more work than the first one for nearly two hours, but after that they did much less than the first gang. This shows that men who wish to do their best work during the entire day should not use beer. =Tobacco and the Muscles.=--Many experiments and studies have shown that the body cannot do its best work when even very small amounts of poison are taken day after day. The poison in tobacco is believed to weaken the muscles so much that no man on a football team in any of our large colleges or universities is allowed to smoke or chew during the season. Persons training for any contest where much strength is required do not use tobacco in any form. =Tobacco prevents Growth of the Muscles.=--The moderate use of tobacco by men has but little effect on the muscles. It may cause them to tire a little more easily when doing very hard work. Tobacco poison does, however, show a marked effect on the muscles of the young. Very careful measurements made at one of the large universities showed that the boys who did not smoke grew one tenth more in weight and one fourth more in height than those using tobacco regularly. This slow growth in tobacco users is partly due to the fact that tobacco makes the muscles in the walls of the blood vessels squeeze together so as to shut off some of the blood from the legs, arms, and other parts, so that they get too little food. Tobacco may also cause less food to be digested for the use of the body. CHAPTER XX HOW THE BODY IS GOVERNED =Making the Parts of the Body Work.=--Each of the hundreds of organs in the body has a certain work to do and this must be done at the right time. In order that all may work together and each one do its part when needed, there is a chief manager called the _brain_ and a helping manager named the _spinal cord_. Millions of tiny threads for sending messages connect the two managers with every part of the body. These threads form the _nerves_. =The Brain.=--The brain is a soft bunch of matter filling the inside of the skull. The bones of the skull are a quarter of an inch thick and prevent any common knocks from hurting the brain. It is surrounded by three coverings which also help shield it from injury. The surface of the brain is very uneven. There are a great many folds separated by grooves. Some of these are more than an inch deep. [Illustration: FIG. 86.--The under side of the brain and the spinal cord with the chief nerves of one side of the body viewed from in front.] =Parts of the Brain.=--The brain is divided into three chief parts. The upper and larger part is called the _big brain_ or _cerebrum_. The lower part behind is the _little brain_ or _cerebellum_. The part under the little brain and round like the thumb is the _stem_ of the brain. It connects the larger parts of the brain with the spinal cord. The big brain is partly separated into halves by a deep cut called a _fissure_. Each half is a _hemisphere_. The outer layer of the brain is gray. It is made of millions of tiny lumps of matter which are the bodies of nerve cells. These are connected by threads much finer than hairs with other parts of the brain and spinal cord. Over these threads called _nerve fibers_ one cell can talk to another somewhat as we talk over a telephone wire. [Illustration: FIG. 87.--Side of the skull cut away to show the brain. _B_, backbone.] =The Spinal Cord.=--This is a bundle of nerve matter about as thick as your finger. It extends from the stem of the brain down the canal in the backbone. The outer layer of the spinal cord is white because it is made of the tiny threads, _nerve fibers_. The inner part is made of the bodies of nerve cells and therefore looks gray. The fibers are branching threads from the cells in the cord and brain. =The Message Carriers or Nerve Fibers.=--In order that the managers may send messages, these fine threads, the nerve fibers, extend from them to all parts of the body. In many places from five to five hundred or more of these fibers are united in one white cord called a _nerve_. Twelve pairs of nerves are joined to the under side of the brain and thirty-one pairs are connected with the spinal cord (Fig. 86). The nerves of the brain branch to all parts of the head and neck, and one pair goes down to the lungs, heart, and stomach. The nerves connected with the spinal cord branch to every part of the muscles, bones, and skin of the arms, trunk, and legs. =How the Nerves do their Work.=--On a telephone wire we can send a message in either direction. A message can travel on a nerve in only one direction. For this reason there must be two kinds of nerves. One kind is called _sending nerves_ because the brain and cord send orders over them to make the organs act. The other kind carries messages to the brain from the eyes, ears, skin, or other organs of sense, telling it how they feel. On this account these are named _receiving nerves_. When we wish to catch a ball, the brain sends an order along the nerve threads down the spinal cord and out through the nerves of the arm to the fingers to get ready to seize a ball. The fingers are spread to grasp the ball, but they do not close until a message goes from the skin of the finger tips to the spinal cord, telling it that the ball is in the hand. =The Work of the Brain.=--The brain is not only the chief manager of the body, but the home of the mind. The mind acts through the brain. The mind receives through the brain what the eye sees, the ear hears, the nose smells, and the fingers feel. All this knowledge is stored up in the mind and called _memory_. These facts and others learned later are worked over by the mind. This is called _thought_. The mind rules and becomes good or bad according to whether it contains good thoughts or bad thoughts. _It is wrong to read books and papers about robberies and murders or to tell or to listen to bad stories_, because in this way evil thoughts get into the mind. The best way of keeping badness out of the mind is to fill it with goodness. It is said that Lincoln was so busy thinking how he could help others that there was no room in his mind for a bad thought. Doing some kindness every day helps much in the making of a good mind. =Habit.=--The doing of anything over and over again until the body goes through the same motions without any or very little thought is called _habit_. The brain and nerves are so formed that when they get used to obeying the same order of the mind again and again, they will carry out these orders when the mind no longer gives them. Sometimes they will continue to obey the old orders even when new ones are given. Many persons would like to break off the habit of drinking beer or whisky, of chewing tobacco, and using bad language, but they find it very hard to make the mind rule the body because they have let the nerves have their own way so long. Speaking cheerfully to those we meet, giving a kind word to our friends, and looking pleasant are good habits which every one ought to form in youth. They not only make the mind better, but they help the body to keep well and will prepare the way for success in life later. Nobody wants a grumbling clerk or a sour-faced housekeeper. [Illustration: FIG. 88.--The difference in appearance between a pouting and a pleasant expression.] =Parts of the Body work without Orders from the Brain.=--A snake with its brain crushed will still squirm and a chicken with its head cut off jumps about. These movements are caused by orders sent from the spinal cord. When the hand or foot is being hurt, the spinal cord orders the muscles to draw the limb away even before we feel the pain in the brain. Many of the movements of the body which are often repeated may be directed by the spinal cord, while the brain is left free to do other work. This is why the spinal cord is called the helping manager. The action of the muscles in the walls of the blood vessels, the working of the stomach, the liver, pancreas, and other glands are not directed by the brain, but by the _sympathetic nerves_. These extend from a little cord on either side of the backbone to all parts of the body and make the organs, such as the heart and sweat glands, which we cannot make obey our will, do their work. =Injury to the Nerves.=--The nerves are so important for the welfare of the body that all the chief ones are placed deep in the flesh, where they are not likely to be hurt. If the nerves leading to the arm were cut, it could not be moved, and we should have no feeling in it. The hurting of a part of the brain, the spinal cord, or the nerves may cause loss of feeling or motion in the leg, arm, or other part of the body. Such a part then seems asleep or dead and is said to have _paralysis_. Pressing on a nerve prevents it from acting. Sitting so as to press on the nerve of the leg often makes the foot go to sleep. The bursting of a blood vessel in the brain may let a blood clot form and press on the nerves which govern the arm or the leg. This pressure may cause paralysis. =Resting the Brain.=--When there is no food in the stomach, it has time to rest. When we sit down or lie down, the muscles get rest. The brain is always busy except when we are asleep. No one can live even a week without sleep. If a dog is kept awake five days, it will die. [Illustration: FIG. 89.--Sleeping in the position shown in the lower figure prevents free breathing and tends to cause round shoulders. The upper figure shows correct position.] Children need much more sleep than older persons. Men and women who work should have about eight hours of sleep daily to remain in good health. Children of twelve years should sleep nine hours each day; those of ten years, ten hours; those of seven years, eleven hours; and those of four years, twelve hours. =Getting the most out of Sleep.=--You should go to bed every night at about the same hour. This will help you to fall asleep as soon as you are in bed. Do not sleep in the clothes which you have worn during the day, but hang them up to air, and put on a night robe. Children should use a very low pillow, so that the body can lie straight in the bed. This gives the lungs and heart freedom to act. Do not lie on the back as this causes some of the organs to press on certain nerves and makes you dream. The windows should be opened wide because fresh air is the best aid to rest and health and keeps away tuberculosis. PRACTICAL QUESTIONS 1. What makes the parts of the body work together? 2. Describe the surface of the brain. 3. Name the three parts of the brain. 4. Of what is the outer layer of the brain made? 5. Where is the spinal cord? 6. What are nerve fibers? 7. What work does the brain do? 8. What makes the mind good or bad? 9. What is habit? 10. How long should children sleep? 11. How can you get the most good out of sleep? CHAPTER XXI HOW NARCOTICS AND STIMULANTS AFFECT THE BRAIN AND NERVES =What Narcotics and Stimulants Are.=--A _narcotic_ is something which when taken into the body makes the organs do their work more slowly and tends to cause sleepiness. Alcoholic drinks, tobacco, opium, soothing sirups, and pain killers are narcotics. A _stimulant_ is a substance which makes the organs of the body do more and quicker work and does not later make the organs work more slowly. Coffee and tea are stimulants. Beer, wine, and whisky were once thought to be stimulants, but experiments have shown them to be narcotics. They urge the brain to faster work for a few minutes, but a half hour later they make it act slower than usual. =Alcohol hurts the Brain.=--Within five minutes after a drink of beer or whisky has been swallowed, part of the alcohol has reached the blood. Within fifteen minutes much of the alcohol has gone from the stomach directly into the blood. In a minute after entering the blood vessels it reaches the brain. If much strong drink is taken, the cells of the brain become so numbed that they cannot give the right orders to the muscles to move the limbs. The person then staggers about and is said to be drunk. Much whisky taken will make the nerve cells so numb that a man cannot move, and he will then lie down as if in a deep sleep. A tablespoonful of whisky will make a child drunk and twice that amount may make him very sick. Much use of strong drink sometimes gives to the brain a terrible disease called _delirium tremens_. In this sickness the man thinks he sees horned animals, hissing snakes, and other creatures which annoy him. =Alcohol injures the Thinking Part of the Brain.=--It was once thought that wine or whisky would make a man think better. Now we know that either of these drinks makes his thoughts slower and also causes him to make mistakes. Two doctors in Europe made many tests with men to learn how alcohol affected their thinking. They found that when using wine the men could do about one tenth less work in adding numbers than when they took no strong drink. These doctors also tested the effect of alcohol on memory and discovered that the use of even small quantities of liquor caused their pupils to learn their lessons more slowly. When persons have taken only a very little drink, they often say and do very foolish things. They sometimes tell secrets, for which they are very sorry when they get sober. Often they become angry at the least cause and strike or even shoot any person who seems to speak or work against them in any way. =Alcohol makes People Steal and Kill.=--The alcohol in strong drink, when often used, appears to deaden that part of the brain which helps the mind know right from wrong. In one year the courts of Suffolk County in Massachusetts found 17,000 persons guilty of doing some wickedness and in over 12,000 of these cases alcohol was found to be the cause of doing the wrong for which they were arrested. Some time ago there were collected the records of 30,000 prisoners, and among these over 12,000 had done their wicked acts while alcohol was numbing the brain. Lately another careful record of over 13,000 prisoners in twelve different states has been studied. In over 4000 of these men the use of strong drink was the first cause of their crimes. =Alcohol makes the Mind Sick.=--Since the mind depends upon certain parts of the brain, whatever hurts the brain is quite sure to hurt the mind. When the mind cannot reason rightly, the person is said to be _insane_. A study of 2000 insane men in New York State showed that the use of alcoholic drink was the cause of the mind sickness in over 500 of them. Of 687 persons in Massachusetts who were so insane that they had to be cared for daily by others, more than 200 of them were brought to this sad condition by alcohol. =Brain of the Young easily overcome by Alcohol.=--No one expects to become a drunkard or a criminal when he first begins to drink. The continued use of alcohol, however, soon numbs the brain and weakens the mind, so that the person's will power is lost. He is then not able to quit drinking even though he wants to stop. He has become a slave to alcohol. _The brain of a young person is injured much more quickly by alcohol than that of an older person and he_ is much more likely to become a slave than one who begins the use of drink late in life. Doctor Lambert, of New York, studied the cases of 259 slaves to alcohol. He learned that four began to drink before six years of age; thirteen between six and twelve years of age; sixty, between twelve and sixteen years; 102 between sixteen and twenty-one years; seventy-one, between twenty-one and thirty years; and only eight after thirty years of age. These facts teach that it is dangerous for the young to take strong drink at any time. =Laws against Alcohol.=--The men who make laws for the good of the people are learning that alcohol is injuring the mind and body of many persons every year. For this reason laws have lately been passed forbidding the sale of strong drink in several entire states and in large parts of many other states. =Tobacco makes the Brain work Slower.=--An examination of the age and habits of hundreds of the students entering a large university in New England showed that those who smoked required more than a year longer than those who did not use tobacco, to learn enough to enter the first classes in this school. Moreover, out of every hundred of those who took the highest rank in their work in the university, ninety-five did not use tobacco. It is likely that tobacco makes the mind work slower by preventing the full amount of blood from going to the brain. It does this by making the blood vessels smaller. So far as known tobacco has but little effect upon the brains of older persons. Superintendent Ogg of Indiana reports that the occasional users of cigarettes are a year, and the regular users two years, behind those who do not smoke. The conduct and honesty of the smokers were also found to be lower than among those who did not smoke. =Opium, Morphine, and Cocaine.=--All of these harmful drugs are widely used in our country. They act on the brain in a strange way. All of them deaden pain. When a person first begins their use, only a small amount is required to produce the effect wanted on the body. Later the doses must be increased. After a few months' use the person becomes a slave to the habit of using them, and he cannot stop their use without the help of a doctor. It is therefore dangerous to use these drugs at any time. Powders used for colds in the nose, also paregoric and laudanum, contain these harmful drugs. =Pain Killers and Soothing Sirups.=--All pain killers contain opium or morphine or other harmful drugs. They are therefore dangerous to use. Pain is useful in telling us that some organ is out of order and needs care. Killing the pain does not help the sick organ, and it may let the organ get so sick as to cause death. One use of the nerves is to tell us when any part of the body is hurt or sick. Pain is nature's warning, and to numb the nerves which tell us about it is as foolish as to kill a person because he brings us bad news. _No medicine should ever be given children to make them sleep or stop their crying except by the advice of the physician._ =Powders and Pills.=--If you get sick, do not try to cure yourself with pills or powders bought at the store. Some of these medicines contain poisons which hurt the heart or other organs. A number of persons have been killed by taking such medicines. When you are sick, go to a good doctor who understands how the organs should work, and he will find which one is out of order and tell you exactly what medicine you need and what to eat in order to get well quickly. =Tea and Coffee.=--These drinks usually wake up the brain and make it work better for a time. If too much of them is used, they may excite the brain in such a way as to make persons nervous. If taken for supper, they may prevent sleep. Children should not use either tea or coffee. Tea sometimes disturbs digestion, and coffee may injure both the stomach and the heart. PRACTICAL QUESTIONS 1. What is a narcotic? 2. Name some narcotics. 3. What is a stimulant? 4. Name some stimulants. 5. How long before alcohol taken reaches the brain? 6. What effect does strong drink have on the brain? 7. Does alcohol help us think better? 8. What facts show that alcohol sends men to prison? 9. What shows that alcohol makes the mind sick? 10. Why is it dangerous for the young to take strong drink? 11. What shows that tobacco makes the brain work slower? 12. Why should you not use opium or morphine? 13. What do pain killers contain? CHAPTER XXII THE SENSES, OR DOORS OF KNOWLEDGE =The Organs of Sense.=--In order that our body may keep out of the way of other persons and find food and drink and do its work, the brain must have some way of receiving news about what is near us, how it looks, and of what it is made. Special organs for receiving knowledge of people and things about us are scattered over the surface of the body. They are called _sense organs_. The chief ones are the two eyes, the two ears, the nose, and many organs of taste in the mouth, and the thousands of tiny organs of feeling in the skin. =The Eye.=--The eye consists of a globe called the _eyeball_ and parts which move this and protect it from injury. Each eyeball is attached at its back part to the large nerve of sight (Fig. 90). This carries messages to the brain, telling it what the eye sees. The eyeball is held in a socket in the front of the skull. A layer of fat lines the socket and keeps the eye from being injured by jars. The _eyebrows_ at the lower edge of the forehead prevent the sweat from running into the eyeball. [Illustration: FIG. 90.--Side of the face cut away to show the eyeball in its socket. _n_ is the nerve of sight; the other letters show the muscles which move the eyeball.] The _eyelids_ can close over the front of the eyeball to shut out dirt or anything else likely to hurt it. The lids have learned to do their work so well that we do not need to think to close them when anything flies toward the eye, for they are shut before we can think. A salty fluid called _tears_ flows from the tear gland at the upper and outer side of the eyeball. The tears keep the front of the eyeball clean. =Parts of the Eyeball.=--The outside of the eyeball is a tough white coat except in front, where it is as clear as glass. Within the outer coat is a very thin black lining to keep the light from scattering. In front the lining is not against the outer coat, but hangs loose and has in it a round hole called the _pupil_ to let the light pass through. The part around the hole is the _iris_. It may be blue, black, or brown, and can squeeze up so as to make the pupil very small when the light is strong. [Illustration: FIG. 91.--A slice from before backward through the eye.] The end of the nerve of sight forms a tender pink covering over most of the inner surface of the eyeball. The cavity within the eyeball is filled with three clear substances. The _lens_, shaped like a flat door knob, is fixed just behind the pupil. In front of the lens is a _watery fluid_ and behind it is a clear _jellylike mass_. The use of the lens and also the other substances is to bend the rays of light together so that they will meet at one place. =How the Eyeball is Moved.=--Six muscles fixed to the bones of the socket holding the eye have their other ends fastened to the tough coat of the eyeball. One muscle turns the ball upward, another turns it downward, one turns it inward and another turns it outward. If an inner or an outer muscle is too strong, a person may have cross eyes. =Keeping the Eye Strong.=--Nearly all young children have perfect eyes. After a year or two in school the eyes of some children become weak. Many children get weak eyes after they are ten or twelve years old. This is because they have not taken care of the eyes. The eyes are often hurt by reading a book with fine print, reading in a dim light, or by leaning over the book so that the eyes look downward instead of straight forward. As the eyes are very weak after measles and most other diseases, they should not be used much until a week or more after recovery. In reading the book should be held a little over a foot in front of the chest and you should sit nearly straight and let the light fall on the page from one side. Never read while lying down because it strains the eyes. Stop reading as soon as the eyes smart. =Helping the Eyes to See.=--Very few old people can see to read without the help of glasses, because the lens of the eye hardens in old age. To see things near by, the shape of the lens must be changed. In some children, the shape of the eyes has become so changed by straining them to read fine print or see things in a dim light that the eyes hurt after being used for any kind of work, and the head may often ache and make the whole body feel bad. Such eyes need help. You should have them examined by an eye doctor who can fit you with glasses which will help you see clearly without headache. =Keeping the Eyes Well.=--Bits of dirt often get beneath the eyelids and cause much pain. By taking hold of the eyelashes the lid may be pulled out from the eye and any dirt removed with the corner of a clean handkerchief passed gently along the lid. The eyes sometimes become sore because they are rubbed with soiled fingers on which are germs. These germs get inside the lids and grow, and in this way poison the eyes. Unless care is used sore eyes are likely to spread from one child to another in the school. The sick child rubs its eyes and then handles a book or pencil on which the germs are smeared by the fingers which touched the eyes. The next child picks up the same book later, gets the germs on the fingers, and then rubs the eyes. For this reason you should never rub the eyes. If you have sore eyes, _be careful that no one else catches the sickness from you_. =The Ear.=--The ear is made of three parts called the _outer ear_, the _middle ear_ or _eardrum_, and the _inner ear_. The outer ear is made of a plate of skin and gristle and a slightly bent tube about one inch long. At the inner end of this tube is a thin membrane or _drumhead_. Beyond the drumhead is the cavity of the middle ear about as large as a pea. A chain of three tiny bones stretches from the outer drumhead across this cavity to a tiny _inner drumhead_. Beyond the inner drumhead is the inner ear. [Illustration: FIG. 92.--View of the ear from in front. Three little bones stretch across the middle ear.] The middle ear is kept full of air by means of a tube leading from it to the throat. A cold or other sickness may cause this tube to fill up and make you deaf. The inner ear consists of a sac and four bent tubes filled with a watery fluid. They are also surrounded by watery fluid contained in channels in a bone of the skull. The end of the nerve of hearing is on one of the tubes. =How we Hear.=--Throwing a stone in the water makes waves which move farther and farther outward. In the same way a noise causes waves in the air. These waves pass into the ear tube, strike the outer drumhead, and make it move. This moves the chain of bones in the middle ear so that they cause motion in the inner drumhead. This in moving back and forth makes waves in the fluid of the inner ear which strike on the ends of the nerve of hearing and cause messages to be carried to the brain. =Care of the Ears.=--The ears should not be struck or pulled, as the eardrum is easily broken. Do not put pencils, pins, or anything else in your ears. Wax naturally forms in the ear tube to keep out bugs and flies. The outer part of the tube may be kept clean by wiping it with a moist cloth over the little finger. If you often have earache or a running ear, you should have it examined by a physician. _Neglecting a sick ear may cause deafness._ Some persons are deaf in one ear and do not know it. Test each ear by covering the other one with a heavy cloth and note how far off you can hear the ticks of a watch. =The Nose.=--The nose has a skin-like lining, but it is always kept moist by little glands which give out a watery fluid. The endings of the nerve of smell are in the lining in the upper part of the nose. Two nerves lead from the nose to the brain. When we catch cold, much blood rushes to the lining of the nose and it becomes swollen. It then gives out a thick white mucus. This covers the nerve endings, so that we cannot smell. Smell is of great use in telling us whether our food is good, by helping us to enjoy food with a pleasant odor, and by warning us against bad air. =The Sense of Taste.=--The nerves by which we taste end in the soft covering of the tongue and some other parts of the mouth. A food cannot be tasted while it is dry. For this reason much slippery fluid flows into the mouth from glands under the ears and tongue. This fluid, called _saliva_, softens the solid food when it is well chewed, so we can taste it. =The Senses of the Skin.=--There are endings of nerves in the skin all over the body. They are of three or four different kinds. Some of them tell us about heat, others tell us about cold. Some tell us about the shape, the smoothness, or hardness of objects, while others tell us when the skin gets hurt. Most of the nerve endings are in the deeper part of the skin, so that they are covered by the epidermis and cannot be hurt by the rough things handled. =Alcohol and the Senses.=--The senses are but little affected by a small amount of alcoholic drink. The sense of taste, after being accustomed to the sharpness of strong drink, may be less easily pleased with the taste of common food and drink. The use of large amounts of alcohol blunts all the senses. In a drunken man the senses of the skin are so numbed that he does not know when anything touches him, and he may be badly burned before he feels the pain. Heavy drinking makes the hearing less keen, enlarges the blood vessels of the eyes, and makes them appear red and bloodshot. =Tobacco and the Senses.=--The use of tobacco does not injure the senses of the skin and usually has no effect on hearing. Both chewing and smoking, if much practiced, make the sense of taste less delicate, so that one cannot enjoy his food to the fullest extent. Much smoking of tobacco may hurt the nerve of sight and in a few cases it has made men blind. Many boys have weakened their eyes by the use of cigarettes. PRACTICAL QUESTIONS 1. Name the chief sense organs. 2. Of what use are the eyelids and tears? 3. Name four parts of the eyeball. 4. What is the iris? 5. Of what use is the lens? 6. What moves the eyeball? 7. When do children get weak eyes? 8. How are the eyes often hurt? 9. How may poor eyes be helped? 10. What makes the eyes sore? 11. How do germs get into the eyes? 12. Name the three parts of the ear. 13. What does the inner ear contain? 14. What may result from neglecting a sick ear? 15. Of what use is smell? 16. Why should food be well chewed? 17. In what part of the skin are most of the nerve endings? 18. What effect does tobacco have on the sense of taste? CHAPTER XXIII KEEPING AWAY SICKNESS =Too Much Sickness.=--Many diseases are caused by our own carelessness and our bad habits of living. We have about one doctor for every one hundred families. There are enough people sick every day to make a city as large as New York or to equal the number of people living in the thirteen states of Idaho, Nevada, Wyoming, Arizona, New Mexico, Utah, Delaware, Montana, Vermont, New Hampshire, North Dakota and South Dakota, and Oklahoma. A careful study of disease and its cause shows that at least one half of all the sickness in our land can be avoided by right living. =The Cause of Sickness.=--Some people are so foolish as to make themselves sick. They weaken the body by using much beer or wine, by breathing bad air, by lack of exercise, or by fast eating. When the body becomes weak, it is likely to get sick at any time. [Illustration: FIG. 93.--The germs of diseases. Much enlarged.] It is not always our own fault when we are sick. It may be caused by the carelessness of others who have let germs escape from their bodies so that they are able to reach us. One half of the sickness in our land is catching sickness. That is, it is sickness which passes from one person to another and is caused by tiny germs or microbes. A catching sickness is called a _contagious disease_. Some of the common catching diseases are sore throat, colds, diphtheria, pneumonia, typhoid fever, measles, grippe, and whooping cough. =How we get a Catching Sickness.=--We get a catching sickness by taking into our bodies the germs from some other person. The germs of the sick do not pass off in the breath, but in the spit or anything else which comes from their bodies. This is why the spit and all slops from the sick room should be burned, buried, or destroyed in some way. [Illustration: FIG. 94.--How the germs of disease start on their mission of death. This sewer carries slops from the houses of the sick and well and empties into a stream used below for drinking water.] We should think it very wicked if a showman should turn his lions and tigers loose in a crowd of women and children. Somebody would surely be killed and others hurt. It is just as wrong to turn loose the germs of the sick by throwing the spit and the slops where they will get into a stream or where the flies may find them and by soiling their feet leave death in their trail wherever they crawl. =How the Germs of Sickness catch Us.=--The germs of sickness have no feet to walk and no wings to fly, yet they easily travel from the sick to the well. They are not killed by being frozen, or drowned by floating in water, or destroyed by drying. For this reason they can travel with the ice, water, milk, and dust. In Buffalo, New York, fifty-seven children caught the scarlet fever in one week by using milk cared for by a boy who was getting well from the scarlet fever. The germs of sickness are so small that a million can hang to the hands or clothing and not be seen. For this reason they are often left clinging to the fingers, desks, books, and pencils, and travel in large numbers on the feet of flies. The surest way the germs have of getting from one person to another is by the common drinking cup. [Illustration: FIG. 95.--Photograph of clear beef broth jelly in which a fly walked five minutes scattering germs. Two days later each germ brushed off the fly's feet grew into a city of germs appearing as a white spot.] =The Common Drinking Cup is an Exchange Station for Germs.=--The most careful examinations have shown that there are thousands of children as well as grown persons who have very light attacks of scarlet fever, tuberculosis, or other diseases and go to school or about their work scattering the germs of sickness in their spit. A child seldom drinks from a cup without leaving on it thousands of germs. Some of these may be germs which will cause sickness. On one drinking cup used in a school, the germs were found to be as thick as the leaves on a maple tree in June. In an Ohio school one warm day, a boy with beginning measles drank from the cup which was afterward used on the same day by the teacher and all the other pupils. In less than two weeks every pupil and the teacher were suffering from measles. _Put nothing into your mouth which has been in another's mouth._ [Illustration: FIG. 96.--A schoolhouse in Morgan county, Ohio, where sixteen pupils and the teacher caught the measles in one day by drinking from a cup which had been used by a boy sick with the measles.] =The Golden Rule.=--If you have a catching sickness, such as measles, chicken pox, or whooping cough, stay away from others. Since the germs of some diseases, like scarlet fever and diphtheria, remain in the spit sometimes several months after you feel well, don't scatter your spit. Hold a handkerchief before your face when you sneeze or cough. _Wash your hands before handling food._ =Some Animals carry Sickness.=--Mosquitoes carry malaria and yellow fever and some other diseases. Flies carry typhoid fever, grippe, diphtheria, and tuberculosis. Bedbugs and fleas carry the plague and leprosy. Rats carry the plague. Cats sometimes carry diphtheria. Many cows have tuberculosis and the germs of this disease are then sometimes found in their milk. Some children have caught tuberculosis from drinking such milk. [Illustration: FIG. 97.--A pane of glass held about two feet before the face of a boy who sneezed. The spots are the droplets of spit thrown out. Each spot showed under the microscope from 50 to 1000 germs.] =Keeping away Smallpox.=--Smallpox was once the most terrible of all diseases. It is so catching that two or three were often sick with it at one time in the same family. Sometimes nearly one half the people of a whole town would have the disease in one year. Over a hundred years ago nearly every grown up person had little pits scattered over his face as a result of having had smallpox. You can always keep away smallpox by being vaccinated. The doctor can vaccinate you by putting on the freshly scraped skin of your arm some weak smallpox germs from a clean healthy calf which has been vaccinated. Your arm will in a few days get sore and you will not feel well for about one week, but you will be made safe from smallpox for several years. Fifty nurses were vaccinated in Philadelphia and cared for many sick with the smallpox, staying with them day after day, but not one of the nurses took the disease. _Every one should be vaccinated when a year old and again at the age of ten or twelve years._ =Colds.=--Some colds are catching, but we generally take cold because we have weak bodies or have been careless. If you want to be free from colds, remember these six rules:-- Don't sit still in wet clothes or with wet feet. Don't sit in a cold draft or in a cold room. Don't sit on the damp ground or on the ice when you are resting from skating. Don't cool off quickly after exercising. Sleep in a room with the windows _wide_ open. Take a cold bath every morning and draw fresh air to the bottom of the lungs many times every day. =Tuberculosis or Consumption.=--This disease is so common and deadly that twenty persons die from it in our country every hour. It is caused by tiny germs (Fig. 63) which lodge in the lungs, glands, bones, or other parts of the body, where they give off poison and hurt the tissues. We take these germs into the body with dust or food, and also by putting to the lips a drinking cup or other things used by a consumptive. Generally the germs will not grow in a strong body, even when they have lodged there. =Preventing Consumption.=--Living in poorly lighted houses without much fresh air, working in dusty rooms, using much strong drink and tobacco, eating poor food, losing sleep, neglecting a cough, and taking little or no outdoor exercise weaken the body so that the consumption germs can grow in it. Deep breathing, sitting and walking erect, living in rooms with sunshine, sleeping with the windows open eight or nine hours every night, and eating good food will prevent one from taking consumption and will often cure the disease. Persons with this sickness give out the germs in their spit, which should be caught in a cup and burned. =The Hookworm Disease.=--This is a sickness affecting thousands of persons in the South. It is caused by tiny worms half as large as a pin hanging fast to the lining of the bowels. The worm is sometimes called the lazy germ because it destroys the red blood cells and makes the body feel weak and lazy. Children with these worms grow slowly, have a dry skin, and a swollen abdomen with a tender spot below the stomach. The disease is easily cured by a physician, but it is better to prevent it by killing the germs in the waste from the bowels. For directions, address the Department of Health at the capital of your state. If the germs reach the ground they crawl around and may get into the well, and enter the body again with the drinking water. Generally, however, the worms enter through the skin of those going barefooted, and are carried by the blood to the lungs. From here they go up the windpipe to the throat, and then down the gullet to the bowels. It is their entrance through the skin that causes ground itch or dew itch. Wearing shoes will help prevent the disease. =A Strong Body Wins.=--Nobody wants to be weak and sickly. Most all of us could keep well if we would try in the right way to keep the body strong. To keep the body in health it must have plenty of sleep, enough good food well chewed, plenty of clean water, exercise every day, and an abundance of fresh air. The body is the temple of the soul. Don't hurt it with bad habits. PRACTICAL QUESTIONS 1. How many people are sick to-day in our country? 2. How can much sickness be avoided? 3. What causes sickness? 4. What is a contagious disease? 5. Name some contagious diseases. 6. How do we get a catching sickness? 7. Why should we be careful with the slops from the sick room? 8. Tell how children in Buffalo caught scarlet fever. 9. What is the danger in using a cup from which others have drunk? 10. How can you prevent others from getting your sickness? 11. Name some animals which carry sickness. 12. How can we keep away smallpox? 13. Give six rules to keep away colds. 14. How may the body be kept strong? CHAPTER XXIV HELPING BEFORE THE DOCTOR COMES =The Need of Quick Help.=--In many places in the country, or when out camping, it is impossible to get a doctor in less than two or three hours. Unless some one at hand can give aid before the doctor comes, much suffering and even death may result when a simple accident occurs. For this reason every one should know how to help in case of such accidents as burns, bleeding, choking, and sunstroke. =Clothing on Fire.=--Children should never play about an open fire. A single spark lighting on a cotton dress may cause it to burst into a blaze so that within a few minutes the child is enveloped in flames. The quickest way to put out such a fire is to wrap the child in a blanket, a piece of carpet, a coat, or any part of your clothing quickly removed. If nothing is at hand to wrap the sufferer in, roll him over and over in the dirt or weeds until the flames are smothered. When your clothing is on fire, you must not run, because this fans the fire and makes it burn. =Burns and Scalds.=--If there is clothing on the part burned, it should be taken off slowly so as not to tear the skin. If the clothing sticks, soak it in oil a few minutes until it gets loose. Cover the burned part as quickly as possible with vaseline or a clean cloth soaked in a quart of boiled water containing a cup of washing soda. Let nothing dirty touch the burned surface and keep it well wrapped. =Bleeding.=--A person can lose a quart of blood without danger of death and may live after more than two quarts have been lost, but it is wise to try to stop any flow of blood as quickly as possible. Tying a clean cloth folded several times over the cut will in most cases stop the flow. This will help a clot to form and will also close the ends of the cut vessels if the bandage is twisted tight with a stick. If the cut is on a limb and the blood comes out in spurts, a bandage tied about the limb between the cut and the body may be twisted tight with a stick so as to press upon the artery and close it. A piece of wood or folded cloth placed over the artery under the bandage before it is tightened is helpful. =Nosebleed.=--Some persons are troubled frequently with bleeding from the nose. The least knock may cause it to bleed for more than an hour. It may generally be stopped without sending for a doctor. Sit up straight to keep the blood out of the head and press the middle part of the nose firmly between the fingers. Apply a cold wet cloth or a lump of ice wrapped in a cloth to the back of the neck. Put a bag of pounded ice on the root of the nose. If it does not stop in a half hour, wet a soft rag or a piece of cotton with cold tea or alum water and put it gently into the bleeding nostril so as to entirely close it. Do not blow the nose for several hours after the bleeding has stopped as this may start it again. =Fainting.=--Fainting may be caused by bad air, an overheated room, by fear, or by some other excitement. A fainting person falls down and appears to be asleep. The lips are pale and there may be cold sweat on the forehead. There is too little blood in the brain, and the heart is weak. A fainting person should be laid flat on the floor or on a couch, and all doors and windows opened wide. Loosen all tight clothing and apply to the forehead a cloth wet with cold water. A faint usually lasts only a few minutes. =Sunstroke.=--A person with sunstroke becomes giddy, sick at the stomach, and weak. He then gets drowsy and may seem as if asleep, but he cannot be aroused. The skin is hot and dry instead of being cold and pale, as in fainting. The doctor should be sent for at once. The first aid for sunstroke is to put the patient in a cool cellar or an icehouse, raise the head, and wet the head, neck, and back of the chest with cold water. As soon as he wakens put him in a cool room. =Frostbite.=--When out in very cold weather, the end of the nose, the tips of the ears, and the toes and fingers are sometimes frozen. If a person comes into a warm room, these frozen parts will give much pain. The parts should be rubbed with snow or ice water until a tingling sensation is felt. =Breaks in the Skin.=--A small cut or tear in the skin may become very sore and cause much trouble if not cared for so as to keep the germs out. If there is dirt in the wound, as when made with a rusty nail or by the bite of a dog, it should be squeezed and washed with boiled water to make it perfectly clean. It may then be bound up in a clean cloth. A little turpentine poured on the wound will help kill the germs which may make it sore. If the dog is thought to be mad or the wound is too deep to be easily washed out to the bottom, a doctor should be called. =Snakebite.=--The scratches made by the little teeth of most snakes, such as the milk snake, garter snake, and black snake, do no more harm than the scratch of a pin. The _copperhead_, the _southern moccasin_, and the _rattlesnake_ have a pair of long teeth called _fangs_ in the upper jaw. These teeth have little canals in them through which the snake presses poison into the bite. [Illustration: FIG. 98.--Photograph of a copperhead snake whose bite may cause death.] If a person is bitten by one of these snakes, the doctor must be sent for and help given at once. Put a bandage above the bite and twist it tight with a stick. Make two or three deep cuts into the bitten place to let out the poisoned blood. Suck the wound to draw out the poison and apply ammonia. =Choking.=--A hard piece of meat, a bone, or a peach seed may slip back into the throat and press so hard on the windpipe as to cut off the air from the lungs. If the object is not far back in the throat, it may be seized with the first finger. A few smart slaps on the upper part of the back while the body is bent forward may drive enough air out of the lungs to push the object outward. =Drowning.=--Every one should learn to swim while young, but no one should venture in deep water. Stiffening of the muscles called cramps often causes the best swimmer to drown. After a person has been under the water two or three minutes he appears lifeless. He may, however, be brought to life if laid face downward, his clothes loosened, and the lungs made to breathe. A heavy folded coat, a piece of sod, or a bunch of weeds should be put under the chest. Then standing astride of him place the hands on the lower ribs and bend forward gradually so as to press on the ribs and push the air out of the lungs. Then straighten your body and slowly lessen pressure on the patient's ribs so that the air will run into the lungs. In this way make the air go in and out of the lungs about fifteen times each minute. =Poisoning.=--Whenever a person has taken poison, a physician should be sent for at once. In most cases an effort should be made to get the poison out of the stomach by causing vomiting. A glass or two of weak, warm soapsuds, a pint of water with a tablespoonful of mustard, or a glass of water with two tablespoonfuls of salt may be taken to make the stomach throw out the poison. Tickling the throat back of the tongue will help cause vomiting. If a strong acid such as carbolic acid or a strong alkali such as ammonia has been taken, do not cause vomiting. For acids give chalk in warm water and a pint of milk. For an alkali give vinegar in water. INDEX Ab do´men, 15. Ad´e noids, 105, 106. Air and health, 111-116. Air sacs, 102, 103. Air tubes, 103. Alcohol, 20, 35. and blood, 124, 125. and blood vessels, 126. and brain, 158-162. and clothing, 98, 99. and crime, 160, 161. and digestion, 57, 58. and health, 74, 75. and kidneys, 93. and lungs, 109, 110. and muscles, 146-148. and senses, 172. and skin, 92, 93. Alcoholic drinks, 68-73. as food, 27, 29. A or´ta, 16. Appetite, 58, 59. Arteries, 19, 119. Backbone, 16. Bac te´ria, 36, 39. of disease, 175-177. of milk, 43. Bathing, 91. Beans, 24. Bedbugs and disease, 134, 178. Beef tea, 31. Beer and digestion, 57, 58. as a food, 27, 35. and heart, 125. making of, 70. Bile, 52, 55. Blackdeath, 11. Bleeding, to stop, 123, 124, 184, 185. Blood, 17, 117, 118. Blood vessels, 19, 118-122. Body, parts of, 15-19. Bones, 135-139. Bowels, 47, 52, 53. Brain, 149-153. Brain, use of, 18. Brandy, 72. Bread, 23. Breathing, 100-107. Building foods, 22, 23. Burns and scalds, 184. Butter, 41. Capillaries, 119, 120. Carbon dioxide, 102, 111. Cells, 20. Cereals, 33. Cer´e brum, 150, 151. Chest, 15. Chewing and health, 49-50. Choking, 187. Cholera, 175. Cider, 40. Cigarettes, 82, 162. Cleanliness, 44, 91. Clothing, 94-99. Co´ca ine, 162. Coffee, 82, 83, 164. Colds, 180. Consumption, 109, 180-181. Cooking of eggs, 34. of meat, 30, 31. Corns, 98. Cotton, 96. Cream, 41. Deafness, 171. Diaphragm (_di´a fram_), 16, 104 Digestion, organs of, 47-52. Diphtheria, 175, 178. Disease, cause of, 25-27. from alcohol, 76, 77. from bad air, 114. from drinking cup, 108, 177. from dust, 108, 109. of eyes, 169. from flies, 108. from insects, 127-134. from milk, 43-46, 178. prevention of, 174-182. Disease, from spit, 107, 108, 178, 179. victory over, 12. Dis til la´tion, 73. Drinking cup and disease, 108, 177. Drowning, 187. Drunkards, cause of, 14. Dust and disease, 37, 108, 109. Dys pep´si a, 50. Ear, 169-171. Eggs, 23, 33, 34. Epidermis, 85, 86. Exercise, 144-146. Eye, 165-168. Fainting, 185. Fat, 24. Fats, 22, 23. Feeding of body, 21. Feeling, 172. Feet, care of, 98. Fish as food, 30. Fleas and disease, 134. Flies and disease, 45-46, 108, 132-134, 176, 178. Food, amount needed, 27. and health, 30-35. digestion of, 47-55. entrance to blood, 52, 54. Foods, 22. Freckles, 87. Frostbite, 186. Fruits, 33, 34. Fuel foods, 23, 24. Gastric juice, 51. Germs, 36-40. of disease, 175, 176. of milk, 43. of spit, 107. Glands, 47-49. Growth of body, 20. Gullet, 16, 53. Habit, 133, 154. Habits, 14. Hair, 88-90. Headache, 55. Hearing, 170. Heart, 16, 100, 118, 122. Hookworm disease, 181, 182. Hookworms, 175. Hy´gi ene, 10. Insects and health, 129-134. Intestine, 16. Intestines, 47, 52, 53. Joints, 139, 140. Kidney, 16. Kidneys, 17, 92. Larynx (_lar´inks_), 102. Leprosy, 134. Life, length of, 9. Ligaments, 135, 139, 140. Linen, 95. Liver, 16, 53, 54, 55, 100. Lung, 16. Lungs, 100-101. Malaria, 175. Measles, 175. Meat, 23. cooking of, 30. spoiling of, 38, 39. Meats, 30. Mi´crobes, 36, 37. Milk, 23, 29, 41-46. and scarlet fever, 176. as a food, 31. souring of, 39. Mineral foods, 24. Mold, 37, 38. Morphine, 83, 84, 162, 163. Mosquitoes and disease, 127-132. Mouth, 60-67. Muscles, 140-143. Muscles and health, 144-148. Nails, 87, 88. Nar cot´ics, 158-164. Nerves, 19, 149, 151, 152. Nose, 104-106, 171. Nose bleed, 181. Opium, 83, 84, 162, 163. Organ, 18. Organs of body, 16. Oxygen, 22. Oysters as a food, 30. Painkillers, 163. Pan´cre as, 16, 48, 52, 53. Pa ral´y sis, 155. Patent medicines, 84. Pharynx (_far´inks_), 47. Plague, 134, 175. Poisoning, 188. Pro´te ids, 22. Pus, 123. Radius, 137. Ribs, 137. Rum, 73. Sa li´va, 48, 49. Salt, 34. Scarlet fever, 175, 176, 178. Sense organs, 165-173. Shoes, 98. Sick, number of, 9. Sickness, how caused, 11. prevention of, 174-182. Silk, 95. Skin, 85-93. senses of, 172. Skull, 136. Sleep, 156, 157. and disease, 113, 114. Sleeping sickness, 134. Slops, care of, 175. Smallpox, 12, 178-180. Smell, 171. Smoking, 57. Snakebites, 186, 187. Sore throat, 175. Soups, 31. Spinal cord, 16, 19, 151, 154, 155. Spit, care of, 175, 178. Spitting and health, 107, 108. Spleen, 54. Starch, 23, 24. Stimulants, 158, 164. Stomach, 16, 47, 50-53, 100. Sugars, 22, 23. Sunstroke, 185. Sweeping and health, 37. Sweetbread, 48. Swimming, 145, 146, 187. Sym pa thet´ic nerves, 155. Taste, 171, 172. Tea, 82, 83, 164. Teeth, 60-67. Thigh, 15. Tissue, 18. Tobacco, 20. and air, 116. and blood, 125. and brain, 162. and digestion, 56, 57. as food, 34, 35. and health, 78-82. and heart, 126. and lungs, 110. and muscles, 148. and senses, 172, 173. Tonsil, 105, 106. Toothache, 62, 63. Tuberculosis, 107, 108, 175. and bad air, 114, 115. cause of, 178, 180. prevention of, 107-109, 111-116, 180-181. Trunk, 15. Typhoid fever, 175. how caused, 25-27, 28, 134. Vaccination, 179, 180. Vegetables as food, 32, 33. Veins, 28, 121. Ventilation, 111-115. Villi, 54. Vocal cords, 105, 106. Voice, 106, 107. Voice box, 102. War, deaths from, 11. Waste, giving out of, 17. Water, use of, 24, 92. Water and health, 25-27, 28. Water in food, 25. Whisky, 72, 73. Whooping cough, 175. Wigglers, 130-131. Windpipe, 16, 102, 103. Wine, 27, 28. and digestion, 58. making of, 70-71. Wounds, 186. Yeast, 39, 40, 69. Yellow fever, 12, 13, 129, 130. BALDWIN AND BENDER'S READERS Reading with Expression By JAMES BALDWIN, Author of Baldwin's School Readers, Harper's Readers, etc. and IDA C. BENDER, Supervisor of Primary Grades, Buffalo, New York. AN EIGHT BOOK SERIES or A FIVE BOOK SERIES The authorship of this series is conclusive evidence of its rare worth, of its happy union of the ideal and the practical. The chief design of the books is to help pupils to acquire the art and habit of reading so well as to give pleasure both to themselves and to those who listen to them. They teach reading with expression, and the selections have, to a large extent, been chosen for this purpose. ¶ These readers are very teachable and readable, and are unusually interesting both in selections and in illustrations. The selections are of a very high literary quality. Besides the choicest schoolbook classics, there are a large number which have never before appeared in school readers. The contents are well balanced between prose and poetry, and the subject matter is unusually varied. Beginning with the Third Reader, selections relating to similar subjects or requiring similar methods of study or recitation, are grouped together. Many selections are in dialogue form and suitable for dramatization. ¶ The First Reader may be used with any method of teaching reading, for it combines the best ideas of each. A number of helpful new features are also included. Each reading lesson is on a right-hand page, and is approached by a series of preparatory exercises on the preceding left-hand page. ¶ The illustrations constitute the finest and most attractive collection ever brought together in a series of readers. There are over 600 in all, every one made especially for these books by an artist of national reputation. AMERICAN BOOK COMPANY HICKS'S CHAMPION SPELLING BOOK By WARREN E. HICKS, Assistant Superintendent of Schools, Cleveland, Ohio Complete, $0.25--Part One, $0.18--Part Two, $0.18 This book embodies the method that enabled the pupils in the Cleveland schools after two years to win the National Education Association Spelling Contest of 1908. ¶ By this method a spelling lesson of ten words is given each day from the spoken vocabulary of the pupil. Of these ten words two are selected for intensive study, and in the spelling book are made prominent in both position and type at the head of each day's lessons, these two words being followed by the remaining eight words in smaller type. Systematic review is provided throughout the book. Each of the ten prominent words taught intensively in a week is listed as a subordinate word in the next two weeks; included in a written spelling contest at the end of eight weeks; again in the annual contest at the end of the year; and again as a subordinate word in the following year's work;--used five times in all within two years. ¶ The Champion Spelling Book consists of a series of lessons arranged as above for six school years, from the third to the eighth, inclusive. It presents about 1,200 words each year, and teaches 312 of them with especial clearness and intensity. It also includes occasional supplementary exercises which serve as aids in teaching sounds, vowels, homonyms, rules of spelling, abbreviated forms, suffixes, prefixes, the use of hyphens, plurals, dictation work, and word building. The words have been selected from lists, supplied by grade teachers of Cleveland schools, of words ordinarily misspelled by the pupils of their respective grades. AMERICAN BOOK COMPANY SPENCERS' PRACTICAL WRITING By PLATT R. SPENCER'S SONS Books 1, 2, 3, 4, 5, 6, 7, and 8 Per dozen, $0.60 SPENCERS' PRACTICAL WRITING has been devised because of the distinct and wide-spread reaction from the use of vertical writing in schools. It is thoroughly up-to-date, embodying all the advantages of the old and of the new. Each word can be written by one continuous movement of the pen. ¶ The books teach a plain, practical hand, moderate in slant, and free from ornamental curves, shades, and meaningless lines. The stem letters are long enough to be clear and unmistakable. The capitals are about two spaces in height. ¶ The copies begin with words and gradually develop into sentences. The letters, both large and small, are taught systematically. In the first two books the writing is somewhat larger than is customary because it is more easily learned by young children. These books also contain many illustrations in outline. The ruling is very simple. ¶ Instruction is afforded showing how the pupil should sit at the desk, and hold the pen and paper. A series of drill movement exercises, thirty-three in number, with directions for their use, accompanies each book. SPENCERIAN PRACTICAL WRITING SPELLER Per dozen, $0.48 This simple, inexpensive device provides abundant drill in writing words. At the same time it trains pupils to form their copies in accordance with the most modern and popular system of penmanship, and saves much valuable time for both teacher and pupil. AMERICAN BOOK COMPANY MAXWELL'S NEW GRAMMARS By WILLIAM H. MAXWELL, Ph.D., LL.D. Superintendent of Schools, City of New York Elementary Grammar $0.40 School Grammar $0.60 The ELEMENTARY GRAMMAR presents in very small space all the grammar usually taught in elementary schools. ¶ It gives the pupil an insight into the general forms in which thought is expressed, and enables him to see the meaning of complicated sentences. The explanatory matter is made clear by the use of simple language, by the elimination of unnecessary technical terms, and by the frequent introduction of illustrative sentences. The definitions are simple and precise. The exercises are abundant and peculiarly ingenious. A novel device for parsing and analysis permits these two subjects to be combined in one exercise for purposes of drill. ¶ The SCHOOL GRAMMAR contains everything needed by students in upper grammar grades and secondary schools. It covers fully the requirements of the Syllabus in English issued by the New York State Education Department. ¶ The book treats of grammar only, and presents many exercises which call for considerable reflection on the meaning of the expressions to be analyzed. Throughout, stress is laid on the broader distinctions of thought and expression. The common errors of written and spoken language are so classified as to make it comparatively easy for pupils to detect and correct them through the application of the rules of grammar. The book ends with an historical sketch of the English language, an article on the formation of words, and a list of equivalent terms employed by other grammarians. The full index makes the volume useful for reference. AMERICAN BOOK COMPANY Transcriber's Note: * Inconsistent hyphenation in the word "skinlike" retained. * Pg 91 Added period after "Clean" located in "Keeping the Skin Clean". * Pg 182 Added period after "sickness" located in "animals which carry sickness". * Pg 188 Removed extraneous comma after "back" located in "throat back, of the tongue". * Pg 190 Index page reference "47" amended to "67" located in "Mouth, 60-47". 
52090	----	MAN A MACHINE BY Julien Offray de la Mettrie FRENCH-ENGLISH INCLUDING FREDERICK THE GREAT'S "EULOGY" ON LA METTRIE AND EXTRACTS FROM LA METTRIE'S "THE NATURAL HISTORY OF THE SOUL" PHILOSOPHICAL AND HISTORICAL NOTES BY GERTRUDE CARMAN BUSSEY M. A., WELLESLEY COLLEGE CHICAGO THE OPEN COURT PUBLISHING CO. 1912 COPYRIGHT BY THE OPEN COURT PUBLISHING CO. 1912 TABLE OF CONTENTS. PAGE Preface v Frederic the Great's Eulogy on Julien Offray De La Mettrie 1 L'Homme Machine 11 Man a Machine 83 The Natural History of the Soul: Extracts 151 Appendix 163 La Mettrie's Relation to His Predecessors and to His Successors 165 Outline of La Mettrie's Metaphysical Doctrine 175 Notes 176 Works Consulted and Cited in the Notes 205 Index 209 PREFACE. The French text presented in this volume is taken from that of a Leyden edition of 1748, in other words, from that of an edition published in the year and in the place of issue of the first edition. The title page of this edition is reproduced in the present volume. The original was evidently the work of a Dutch compositor unschooled in the French language, and is full of imperfections, inconsistencies, and grammatical blunders. By the direction of the publishers these obviously typographical blunders have been corrected by M. Lucien Arréat of Paris. The translation is the work of several hands. It is founded on a version made by Miss Gertrude C. Bussey (from the French text in the edition of J. Assezat) and has been revised by Professor M. W. Calkins who is responsible for it in its present form. Mademoiselle M. Carret, of the Wellesley College department of French, and Professor George Santayana, of Harvard University, have given valued assistance; and this opportunity is taken to acknowledge their kindness in solving the problems of interpretation which have been submitted to them. It should be added that the translation sometimes subordinates the claims of English structure and style in the effort to render La Mettrie's meaning exactly. The paragraphing of the French is usually followed, but the italics and the capitals are not reproduced. The page-headings of the translation refer back to the pages of the French text; and a few words inserted by the translators are enclosed in brackets. The philosophical and historical Notes are condensed and adapted from a master's thesis on La Mettrie presented by Miss Bussey to the faculty of Wellesley College. FREDERIC THE GREAT'S EULOGY ON JULIEN OFFRAY DE LA METTRIE. Julien Offray de la Mettrie was born in Saint Malo, on the twenty-fifth of December, 1709, to Julien Offray de la Mettrie and Marie Gaudron, who were living by a trade large enough to provide a good education for their son. They sent him to the college of Coutance to study the humanities; he went from there to Paris, to the college of Plessis; he studied his rhetoric at Caen, and since he had much genius and imagination, he won all the prizes for eloquence. He was a born orator, and was passionately fond of poetry and belles-lettres, but his father thought that he would earn more as an ecclesiastic than as a poet, and destined him for the church. He sent him, the following year, to the college of Plessis where he studied logic under M. Cordier, who was more a Jansenist than a logician. It is characteristic of an ardent imagination to seize forcefully the objects presented to it, as it is characteristic of youth to be prejudiced in favor of the first opinions that are inculcated. Any other scholar would have adopted the opinions of his teacher but that was not enough for young La Mettrie; he became a Jansenist, and wrote a work which had great vogue in that party. In 1725, he studied natural philosophy at the college of Harcourt, and made great progress there. On his return to Brittany, M. Hunault, a doctor of Saint Malo, had advised him to adopt the medical profession. They had persuaded his father, assuring him that a mediocre physician would be better paid for his remedies than a good priest for absolutions. At first young La Mettrie had applied himself to the study of anatomy: for two years he had worked at the dissecting-table. After this, in 1725, he took the degree of doctor at Rheims, and was there received as a physician. In 1733, he went to Leyden to study under the famous Boerhaave. The master was worthy of the scholar and the scholar soon made himself worthy of the master. M. La Mettrie devoted all the acuteness of his mind to the knowledge and to the healing of human infirmities; and he soon became a great physician. In the year 1734, during his leisure moments, he translated a treatise of the late M. Boerhaave, his Aphrodisiacus, and joined to it a dissertation on venereal maladies, of which he himself was the author. The old physicians in France rose up against a scholar who affronted them by knowing as much as they. One of the most celebrated doctors of Paris did him the honor of criticizing his work (a sure proof that it was good). La Mettrie replied; and, to confound his adversary still more, he composed in 1736 a treatise on vertigo, esteemed by all impartial physicians. By an unfortunate effect of human imperfection a certain base jealousy has come to be one of the characteristics of men of letters. This feeling incites those who have reputations, to oppose the progress of budding geniuses. This blight often fastens on talents without destroying them, but it sometimes injures them. M. La Mettrie, who was advancing in the career of science at a giant's pace, suffered from this jealousy, and his quick temper made him too susceptible to it. In Saint Malo, he translated the "Aphorisms" of Boerhaave, the "Materia Medica," the "Chemical Proceedings," the "Chemical Theory," and the "Institutions," by this same author. About the same time, he published an abstract of Sydenham. The young doctor had learned by premature experience, that if he wished to live in peace, it was better to translate than to compose; but it is characteristic of genius to escape from reflection. Counting on himself alone, if I may speak thus, and filled with the knowledge he had gained from his infinitely skilful researches into nature, he wished to communicate to the public the useful discoveries he had made. He published his treatise on smallpox, his "Practical Medicine," and six volumes of commentary on the physiology of Boerhaave. All these works appeared at Paris, although the author had written them at Saint Malo. He joined to the theory of his art an always successful practice, which is no small recommendation for a physician. In 1742, La Mettrie came to Paris, led there by the death of M. Hunault, his old teacher. Morand and Sidobre introduced him to the Duke of Gramont, who, a few days after, obtained for him the commission of physician of the guards. He accompanied the Duke to war, and was with him at the battle of Dettingen, at the siege of Freiburg, and at the battle of Fontenoy, where he lost his patron, who was killed by a cannon shot. La Mettrie felt this loss all the more keenly, because it was at the same time the reef on which his fortune was wrecked. This is what happened. During the campaign of Freiburg, La Mettrie had an attack of violent fever. For a philosopher an illness is a school of physiology; he believed that he could clearly see that thought is but a consequence of the organization of the machine, and that the disturbance of the springs has considerable influence on that part of us which the metaphysicians call soul. Filled with these ideas during his convalescence, he boldly bore the torch of experience into the night of metaphysics; he tried to explain by the aid of anatomy the thin texture of understanding, and he found only mechanism where others had supposed an essence superior to matter. He had his philosophic conjectures printed under the title of "The Natural History of the Soul." The chaplain of the regiment sounded the tocsin against him, and at first sight all the devotees cried out against him. The common ecclesiastic is like Don Quixote, who found marvelous adventures in commonplace events, or like the famous soldier, so engrossed with his system that he found columns in all the books he read. The majority of priests examine all works of literature as if they were treatises on theology, and filled with this one aim, they discover heresies everywhere. To this fact are due very many false judgments and very many accusations, for the most part unfair, against the authors. A book of physics should be read in the spirit of a physicist; nature, the truth, is its sole judge, and should absolve or condemn it. A book of astronomy should be read in the same manner. If a poor physician proves that the blow of a stick smartly rapped on the skull disturbs the mind, or that at a certain degree of heat reason wanders, one must either prove the contrary or keep quiet. If a skilful astronomer proves, in spite of Joshua, that the earth and all the celestial globes revolve around the sun, one must either calculate better than he, or admit that the earth revolves. But the theologians, who, by their continual apprehension, might make the weak believe that their cause is bad, are not troubled by such a small matter. They insisted on finding seeds of heresy in a work dealing with physics. The author underwent a frightful persecution, and the priests claimed that a doctor accused of heresy could not cure the French guards. To the hatred of the devotees was joined that of his rivals for glory. This was rekindled by a work of La Mettrie's entitled "The Politics of Physicians." A man full of cunning, and carried away by ambition, aspired to the place, then vacant, of first physician to the king of France. He thought that he could gain it by heaping ridicule upon those of his contemporaries who might lay claim to this position. He wrote a libel against them, and abusing the easy friendship of La Mettrie, he enticed him to lend to it the volubility of his pen, and the richness of his imagination. Nothing more was needed to complete the downfall of a man little known, against whom were all appearances, and whose only protection was his merit. For having been too sincere as a philosopher and too obliging as a friend, La Mettrie was compelled to leave his country. The Duke of Duras and the Viscount of Chaila advised him to flee from the hatred of the priests and the revenge of the physicians. Therefore, in 1746, he left the hospitals of the army where he had been placed by M. Sechelles, and came to Leyden to philosophize in peace. He there composed his "Penelope," a polemical work against the physicians in which, after the fashion of Democritus, he made fun of the vanity of his profession. The curious result was that the doctors themselves, though their quackery was painted in true colors, could not help laughing when they read it, and that is a sure sign that they had found more wit than malice in it. M. La Mettrie after losing sight of his hospitals and his patients, gave himself up completely to speculative philosophy; he wrote his "Man a Machine" or rather he put on paper some vigorous thoughts about materialism, which he doubtless planned to rewrite. This work, which was bound to displease men who by their position are declared enemies of the progress of human reason, roused all the priests of Leyden against its author. Calvinists, Catholics and Lutherans forgot for the time that consubstantiation, free will, mass for the dead, and the infallibility of the pope divided them: they all united again to persecute a philosopher who had the additional misfortune of being French, at a time when that monarchy was waging a successful war against their High Powers. The title of philosopher and the reputation of being unfortunate were enough to procure for La Mettrie a refuge in Prussia with a pension from the king. He came to Berlin in the month of February in the year 1748; he was there received as a member of the Royal Academy of Science. Medicine reclaimed him from metaphysics, and he wrote a treatise on dysentery, another on asthma, the best that had then been written on these cruel diseases. He sketched works on certain philosophical subjects which he had proposed to look into. By a sequence of accidents which befell him these works were stolen, but he demanded their suppression as soon as they appeared. La Mettrie died in the house of Milord Tirconnel, minister plenipotentiary of France, whose life he had saved. It seems that the disease, knowing with whom it had to deal, was clever enough to attack his brain first, so that it would more surely confound him. He had a burning fever and was violently delirious. The invalid was obliged to depend upon the science of his colleagues, and he did not find there the resources which he had so often found in his own, both for himself and for the public. He died on the eleventh of November, 1751, at the age of forty-three years. He had married Louise Charlotte Dréano, by whom he left only a daughter, five years and a few months old. La Mettrie was born with a fund of natural and inexhaustible gaiety; he had a quick mind, and such a fertile imagination that it made flowers grow in the field of medicine. Nature had made him an orator and a philosopher; but a yet more precious gift which he received from her, was a pure soul and an obliging heart. All those who are not imposed upon by the pious insults of the theologians mourn in La Mettrie a good man and a wise physician. FACSIMILE OF TITLE PAGE OF THE LEYDEN 1748 EDITION L'HOMME MACHINE. Est-ce là ce Raion de l'Essence suprème, Que l'on nous peint si lumineux? Est-ce là cet Esprit survivant à nous même? Il naît avec nos sens, croit, s'affoiblit comme eux. Helas! il périra de même. Voltaire. À LEYDE, De l'Imp. d'ELIE LUZAC, Fils. ----- MDCCXLVIII. L'HOMME MACHINE. Il ne suffit pas à un sage d'étudier la nature et la vérité; il doit oser la dire en faveur du petit nombre de ceux qui veulent et peuvent penser; car pour les autres, qui sont volontairement esclaves des préjugés, il ne leur est pas plus possible d'atteindre la vérité, qu'aux grenouilles de voler. Je réduis à deux les systèmes des philosophes sur l'âme de l'homme. Le premier, et le plus ancien, est le système du matérialisme; le second est celui du spiritualisme. Les métaphysiciens qui ont insinué que la matière pourrait bien avoir la faculté de penser, n'ont pas déshonoré leur raison. Pourquoi? C'est qu'ils ont cet avantage (car ici c'en est un) de s'être mal exprimés. En effet, demander si la matière peut penser, sans la considérer autrement qu'en elle-même, c'est demander si la matière peut marquer les heures. On voit d'avance que nous éviterons cet écueil, où Mr. Locke a eu le malheur d'échouer. Les Leibniziens, avec leurs monades, ont élevé une hypothèse inintelligible. Ils ont plutôt spiritualisé la matière, que matérialisé l'âme. Comment peut-on définir un être dont la nature nous est absolument inconnue? Descartes, et tous les Cartésiens, parmi lesquels il y a longtemps qu'on a compté les Malebranchistes, ont fait la même faute. Ils ont admis deux substances distinctes dans l'homme, comme s'ils les avaient vues et bien comptées. Les plus sages ont dit que l'âme ne pouvait se connaître que par les seules lumières de la Foi: cependant, en qualité d'êtres raisonnables, ils ont cru pouvoir se réserver le droit d'examiner ce que l'Ecriture a voulu dire par le mot Esprit, dont elle se sert en parlant de l'âme humaine; et dans leurs recherches, s'ils ne sont pas d'accord sur ce point avec les théologiens, ceux-ci le sont-ils davantage entr'eux sur tous les autres? Voici en peu de mots le résultat de toutes leurs réflexions. S'il y a un Dieu, il est auteur de la Nature, comme de la Révélation; il nous a donné l'une, pour expliquer l'autre; et la Raison, pour les accorder ensemble. Se défier des connaissances qu'on peut puiser dans les corps animés, c'est regarder la Nature et la Révélation comme deux contraires qui se détruisent; et par conséquent, c'est oser soutenir cette absurdité: que Dieu se contredit dans ses divers ouvrages, et nous trompe. S'il y a une Révélation, elle ne peut donc démentir la Nature. Par la Nature seule, on peut découvrir le sens des paroles de l'Evangile, dont l'expérience seule est la véritable interprète. En effet, les autres commentateurs jusqu'ici n'ont fait qu'embrouiller la vérité. Nous allons en juger par l'auteur du Spectacle de la Nature. "Il est étonnant, dit-il (au sujet de Mr. Locke), qu'un homme qui dégrade notre âme jusqu'à la croire une âme de boue, ose établir la Raison pour juge et souverain arbitre des mystères de la Foi; car, ajoute-t-il, quelle idée étonnante aurait-on du Christianisme, si l'on voulait suivre la Raison?" Outre que ces réflexions n'éclaircissent rien par rapport à la Foi, elles forment de si frivoles objections contre la méthode de ceux qui croient pouvoir interpréter les Livres Saints, que j'ai presque honte de perdre le temps à les réfuter. 1º. L'excellence de la Raison ne dépend pas d'un grand mot vide de sens (l'immatérialité); mais de sa force, de son étendue, ou de sa clairvoyance. Ainsi une âme de boue, qui découvrirait, comme d'un coup d'oeil, les rapports et les suites d'une infinité d'idées difficiles à saisir, serait évidemment préférable à une âme sotte et stupide qui serait faite des éléments les plus précieux. Ce n'est pas être philosophe, que de rougir avec Pline de la misère de notre origine. Ce qui parait vil, est ici la chose la plus précieuse, et pour laquelle la nature semble avoir mis le plus d'art et le plus d'appareil. Mais comme l'homme, quand même il viendrait d'une source encore plus vile en apparence, n'en serait pas moins le plus parfait de tous les êtres, quelle que soit l'origine de son âme, si elle est pure, noble, sublime, c'est une belle âme, qui rend respectable quiconque en est doué. La seconde manière de raisonner de Mr. Pluche me parait vicieuse, même dans son système, qui tient un peu du fanatisme; car si nous avons une idée de la Foi, qui soit contraire aux principes les plus clairs, aux vérités les plus incontestables, il faut croire, pour l'honneur de la Révélation et de son Auteur, que cette idée est fausse, et que nous ne connaissons point encore les sens des paroles de l'Evangile. De deux choses l'une; ou tout est illusion, tant la Nature même, que la Révélation; ou l'expérience seule peut rendre raison de la Foi. Mais quel plus grand ridicule que celui de notre auteur? Je m'imagine entendre un péripatéticien, qui dirait: "Il ne faut pas croire l'expérience de Toricelli: car si nous la croyions, si nous allions bannir l'horreur du vide, quelle étonnante philosophie aurions-nous?" J'ai fait voir combien le raisonnement de Mr. Pluche est vicieux, [1] afin de prouver premièrement que s'il y a une Révélation, elle n'est point suffisamment démontrée par la seule autorité de l'Eglise et sans aucun examen de la Raison, comme le prétendent tous ceux qui la craignent. Secondement, pour mettre à l'abri de toute attaque la méthode de ceux qui voudraient suivre la voie que je leur ouvre, d'interpréter les choses surnaturelles, incompréhensibles en soi, par les lumières que chacun a reçues de la nature. L'expérience et l'observation doivent donc seules nous guider ici. Elles se trouvent sans nombre dans les Fastes des médecins, qui ont été philosophes, et non dans les philosophes, qui n'ont pas été médecins. Ceux-ci ont parcouru, ont éclairé le labyrinthe de l'homme; ils nous ont seuls dévoilé ces ressorts cachés sous des enveloppes qui dérobent à nos yeux tant de merveilles. Eux seuls, contemplant tranquillement notre âme, l'ont mille fois surprise, et dans sa misère, et dans sa grandeur, sans plus la mépriser dans l'un de ces états, que l'admirer dans l'autre. Encore une fois, voilà les seuls physiciens qui aient droit de parler ici. Que nous diraient les autres, et surtout les théologiens? N'est-il pas ridicule de les entendre décider sans pudeur, sur un sujet qu'ils n'ont point été à portée de connaître, dont ils ont été au contraire entièrement détournés par des études obscures, qui les ont conduits à mille préjugés, et pour tout dire en un mot, au fanatisme, qui ajoute encore à leur ignorance dans le mécanisme des corps. Mais, quoique nous ayons choisi les meilleurs guides, nous trouverons encore beaucoup d'épines et d'obstacles dans cette carrière. L'homme est une machine si composée, qu'il est impossible de s'en faire d'abord une idée claire, et conséquemment de la définir. C'est pourquoi toutes les recherches que les plus grands philosophes ont faites à priori, c'est à dire, en voulant se servir en quelque sorte des ailes de l'esprit, ont été vaines. Ainsi ce n'est qu'à posteriori, ou en cherchant à demêler l'âme comme au travers les organes du corps, qu'on peut, je ne dis pas découvrir avec évidence la nature même de l'homme, mais atteindre le plus grand degré de probabilité possible sur ce sujet. Prenons donc le bâton de l'expérience, et laissons là l'histoire de toutes les vaines opinions des philosophes. Etre aveugle, et croire pouvoir se passer de ce bâton, c'est le comble de l'aveuglement. Qu'un moderne a bien raison de dire qu'il n'y a que la vanité seule qui ne tire pas des causes secondes le même parti que des premières! On peut et on doit même admirer tous ces beaux génies dans leurs travaux les plus inutiles, les Descartes, les Malebranche, les Leibnitz, les Wolf, etc.; mais quel fruit, je vous prie, a-t-on retiré de leurs profondes méditations et de tous leurs ouvrages? Commençons donc et voyons, non ce qu'on a pensé, mais ce qu'il faut penser pour le repos de la vie. Autant de tempéraments, autant d'esprits, de caractères et de moeurs différentes. Galien même a connu cette vérité, que Descartes, et non Hippocrate, comme le dit l'auteur de l'histoire de l'Ame, a poussée loin, jusqu'à dire que la médecine seule pouvait changer les esprits et les moeurs avec le corps. Il est vrai, la mélancolie, la bile, le phlegme, le sang etc., suivant la nature, l'abondance et la diverse combinaison de ces humeurs, de chaque homme font un homme différent. Dans les maladies, tantôt l'âme s'éclipse et ne montre aucun signe d'elle-même; tantôt on dirait qu'elle est double, tant la fureur la transporte; tantôt l'imbécilité se dissipe: et la convalescence d'un sot fait un homme d'esprit. Tantôt le plus beau génie devenu stupide, ne se reconnait plus. Adieu toutes ces belles connaissances acquises à si grands frais, et avec tant de peine! Ici c'est un paralytique, qui demande si sa jambe est dans son lit: là c'est un soldat qui croit avoir le bras qu'on lui a coupé. La mémoire de ses anciennes sensations, et du lieu où son âme les rapportait, fait son illusion et son espèce de délire. Il suffit de lui parler de cette partie qui lui manque, pour lui en rappeller et faire sentir tous les mouvements; ce qui se fait avec je ne sais quel déplaisir d'imagination qu'on ne peut exprimer. Celui-ci pleure, comme un enfant, aux approches de la mort, que celui-là badine. Que fallait-il à Caius Julius, à Sénèque, à Pétrone pour changer leur intrépidité en pusillanimité ou en poltronnerie? Une obstruction dans la rate, dans le foie, un embarras dans la veine porte. Pourquoi? Parceque l'imagination se bouche avec les viscères; et de là naissent tous ces singuliers phénomènes de l'affection hystérique et hypocondriaque. Que dirais-je de nouveau sur ceux qui s'imaginent être transformés en loups-garous, en coqs, en vampires, qui croient que les morts les sucent? Pourquoi m'arrêterais-je à ceux qui voient leur nez, ou autres membres, de verre, et à qui il faut conseiller de coucher sur la paille, de peur qu'ils ne se cassent, afin qu'ils en retrouvent l'usage et la véritable chair, lorsque mettant le feu à la paille on leur fait craindre d'être brûlés: frayeur qui a quelquefois guéri la paralysie? Je dois légèrement passer sur des choses connues de tout le monde. Je ne serai pas plus long sur le détail des effets du sommeil. Voyez ce soldat fatigué! il ronfle dans la tranchée, au bruit de cent pièces de canons! Son âme n'entend rien, son sommeil est une parfaite apoplexie. Une bombe va l'écraser; il sentira peut-être moins ce coup qu'un insecte qui se trouve sous le pied. D'un autre côté, cet homme que la jalousie, la haine, l'avarice ou l'ambition dévore, ne peut trouver aucun repos. Le lieu le plus tranquille, les boissons les plus fraîches et les plus calmantes, tout est inutile à qui n'a pas délivré son coeur du tourment des passions. L'âme et le corps s'endorment ensemble. A mesure que le mouvement du sang se calme, un doux sentiment de paix et de tranquillité se répand dans toute la machine; l'âme se sent mollement s'appesantir avec les paupières et s'affaisser avec les fibres du cerveau: elle devient ainsi peu à peu comme paralytique, avec tous les muscles du corps. Ceux-ci ne peuvent plus porter le poids de la tête; celle là ne peut plus soutenir le fardeau de la pensée; elle est dans le sommeil, comme n'étant point. La circulation se fait-elle avec trop de vitesse? l'âme ne peut dormir. L'âme est-elle trop agitée, le sang ne peut se calmer; il galope dans les veines avec un bruit qu'on entend: telles sont les deux causes réciproques de l'insomnie. Une seule frayeur dans les songes fait battre le coeur à coups redoublés, et nous arrache à la nécessité, ou à la douceur du repos, comme feraient une vive douleur ou des besoins urgents. Enfin, comme la seule cessation des fonctions de l'âme procure le sommeil, il est, même pendant la veille (qui n'est alors qu'une demi-veille), des sortes de petits sommeils d'âme très fréquents, des rêves à la Suisse, qui prouvent que l'âme n'attend pas toujours le corps pour dormir; car si elle ne dort pas tout-à-fait, combien peu s'en faut-il! puisqu'il lui est impossible d'assigner un seul objet auquel elle ait prêté quelque attention, parmi cette foule innombrable d'idées confuses, qui comme autant de nuages remplissent, pour ainsi dire, l'atmosphère de notre cerveau. L'opium a trop de rapport avec le sommeil qu'il procure, pour ne pas le placer ici. Ce remède enivre, ainsi que le vin, le café, et chacun à sa manière, et suivant sa dose. Il rend l'homme heureux dans un état qui semblerait devoir être le tombeau du sentiment, comme il est l'image de la mort. Quelle douce léthargie! L'âme n'en voudrait jamais sortir. Elle était en proie aux plus grandes douleurs; elle ne sent plus que le seul plaisir de ne plus suffrir et de jouir de la plus charmante tranquillité. L'opium change jusqu'à la volonté; il force l'âme qui voulait veiller et se divertir, d'aller se mettre au lit malgré elle. Je passe sous silence l'histoire des poisons. C'est en fouettant l'imagination, que le café, cet antidote du vin, dissipe nos maux de tête et nos chagrins, sans nous en ménager, comme cette liqueur, pour le lendemain. Contemplons l'âme dans ses autres besoins. Le corps humain est une machine qui monte elle-même ses ressorts; vivante image du mouvement perpétuel. Les aliments entretiennent ce que la fièvre excite. Sans eux l'âme languit, entre en fureur et meurt abattue. C'est une bougie dont la lumière se ranime, au moment de s'éteindre. Mais nourrissez le corps, versez dans ses tuyaux des sucs vigoureux, des liqueurs fortes; alors l'âme généreuse comme elles s'arme d'un fier courage et le soldat que l'eau eut fait fuir, devenu féroce, court gaiement à la mort au bruit des tambours. C'est ainsi que l'eau chaude agite un sang que l'eau froide eut calmé. Quelle puissance d'un repas! La joie renaît dans un coeur triste; elle passe dans l'âme des convives qui l'expriment par d'aimables chansons, où les Français excellent. Le mélancolique seul est accablé, et l'homme d'étude n'y est plus propre. La viande crue rend les animaux féroces; les hommes le deviendraient par la même nourriture; cela est si vrai, que la nation anglaise, qui ne mange pas la chair si cuite que nous, mais rouge et sanglante, parait participer de cette férocité plus ou moins grande, qui vient en partie de tels aliments, et d'autres causes, que l'éducation peut seule rendre impuissantes. Cette férocité produit dans l'âme l'orgueil, la haine, le mépris des autres nations, l'indocilité et autres sentiments, qui dépravent le caractère, comme des aliments grossiers font un esprit lourd, épais, dont la paresse et l'indolence sont les attributs favoris. Mr. Pope a bien connu tout l'empire de la gourmandise, lorsqu'il dit: "Le grave Catius parle toujours de vertu, et croit que, qui souffre les vicieux est vicieux lui-même. Ces beaux sentiments durent jusqu'à l'heure du diner; alors il préfère un scélérat, qui a une table délicate, à un saint frugal. "Considérez, dit-il ailleurs, le même homme en santé, ou en maladie; possédant une belle charge, ou l'ayant perdue; vous le verrez chérir la vie, ou la détester, fou à la chasse, ivrogne dans une assemblée de province, poli au bal, bon ami en ville, sans foi à la cour." Nous avons eu en Suisse un bailli, nommé Steiguer de Wittighofen; il était à jeûn le plus intègre et même le plus indulgent des juges; mais malheur au misérable qui se trouvait sur la sellette, lorsqu'il avait fait un grand diner! Il était homme à faire pendre l'innocent, comme le coupable. Nous pensons, et même nous ne sommes honnêtes gens, que comme nous sommes gais, ou braves; tout dépend de la manière dont notre machine est montée. On dirait en certains moments que l'âme habite dans l'estomac, et que Van Helmont, en mettant son siège dans le pylore, ne se serait trompé qu'en prenant la partie pour le tout. A quels excès la faim cruelle peut nous porter! Plus de respect pour les entrailles auxquelles on doit ou on a donné la vie; on les déchire à belles dents, on s'en fait d'horribles festins; et dans la fureur dont on est transporté, le plus faible est toujours la proie du plus fort. La grossesse, cette émule désirée des pâles couleurs, ne se contente pas d'amener le plus souvent à sa suite les goûts dépravés qui accompagnent ces deux états: elle a quelquefois fait exécuter à l'âme les plus affreux complots; effets d'une manie subite, qui étouffe jusqu'à la loi naturelle. C'est ainsi que le cerveau, cette matrice de l'esprit, se pervertit à sa manière, avec celle du corps. Quelle autre fureur d'homme ou de femme, dans ceux que la continence et la santé poursuivent! C'est peu pour cette fille timide et modeste d'avoir perdu toute honte et toute pudeur; elle ne regarde plus l'inceste, que comme une femme galante regarde l'adultère. Si ses besoins ne trouvent pas de prompts soulagements, ils ne se borneront point aux simples accidents d'une passion utérine, à la manie, etc.; cette malheureuse mourra d'un mal, dont il y a tant de médecins. Il ne faut que des yeux pour voir l'influence nécessaire de l'âge sur la raison. L'âme suit les progrès du corps, comme ceux de l'éducation. Dans le beau sexe, l'âme suit encore la délicatesse du tempérament: de là cette tendresse, cette affection, ces sentiments vifs, plutôt fondés sur la passion que sur la raison, ces préjugés, ces superstitions, dont la forte empreinte peut à peine s'effacer, etc. L'homme, au contraire, dont le cerveau et les nerfs participent de la fermeté de tous les solides, a l'esprit, ainsi que les traits du visage, plus nerveux: l'éducation, dont manquent les femmes, ajoute encore de nouveaux degrés de force à son âme. Avec de tels secours de la nature et de l'art, comment ne serait-il pas plus reconnaissant, plus généreux, plus constant en amitié, plus ferme dans l'adversité? etc. Mais, suivant à peu près la pensée de l'auteur des Lettres sur les Physionomies, qui joint les grâces de l'esprit et du corps à presque tous les sentiments du c�ur les plus tendres et les plus délicats ne doit point nous envier une double force, qui ne semble avoir été donnée à l'homme, l'une, que pour se mieux pénétrer des attraits de la beauté, l'autre, que pour mieux servir à ses plaisirs. Il n'est pas plus nécessaire d'être aussi grand physionomiste que cet auteur pour deviner la qualité de l'esprit par la figure ou la forme des traits, lorsqu'ils sont marqués jusqu'à un certain point, qu'il ne l'est d'être grand médecin pour connaître un mal accompagné de tous ses symptomes évidents. Examinez les portraits de Locke, de Steele, de Boerhaave, de Maupertuis, etc. vous ne serez point surpris de leur trouver des physionomies fortes, des yeux d'aigle. Parcourez-en une infinité d'autres, vous distinguerez toujours le beau du grand génie, et même souvent l'honnête homme du fripon. On a remarqué, par exemple, qu'un poète célèbre réunit (dans son portrait) l'air d'un filou, avec le feu de Prométhée. L'histoire nous offre un mémorable exemple de la puissance de l'air. Le fameux Duc de Guise était si fort convaincu que Henri III. qui l'avait eu tant de fois en son pouvoir, n'oserait jamais l'assassiner, qu'il partit pour Blois. Le chancelier Chyverni apprenant son départ, s'écria: voilà un homme perdu! Lorsque sa fatale prédiction fut justifiée par l'événement, on lui en demanda la raison. Il y a vingt ans, dit-il, que je connais le Roi; il est naturellement bon et même faible; mais j'ai observé qu'un rien l'impatiente et le met en fureur, lorsqu'il fait froid. Tel peuple a l'esprit lourd et stupide; tel autre l'a vif, léger, pénétrant. D'où cela vient-il, si ce n'est en partie, et de la nourriture qu'il prend, et de la semence de ses pères, [2] et de ce chaos de divers éléments qui nagent dans l'immensité de l'air? L'esprit a, comme le corps, ses maladies épidémiques et son scorbut. Tel est l'empire du climat, qu'un homme qui en change se ressent malgré lui de ce changement. C'est une plante ambulante, qui s'est elle-même transplantée; si le climat n'est plus le même, il est juste qu'elle dégénère, ou s'améliore. On prend tout encore de ceux avec qui l'on vit, leurs gestes, leurs accents, etc., comme la paupière se baisse à la menace du coup dont on est prévenu, ou par la même raison que le corps du spectateur imite machinalement, et malgré lui, tous les mouvements d'un bon pantomime. Ce que je viens de dire prouve que la meilleure compagnie pour un homme d'esprit, est la sienne, s'il n'en trouve une semblable. L'esprit se rouille avec ceux qui n'en ont point, faute d'être exercé: à la paume, on renvoie mal la balle à qui la sert mal. J'aimerais mieux un homme intelligent, qui n'aurait eu aucune éducation, que s'il en eût eu une mauvaise, pourvu qu'il fût encore assez jeune. Un esprit mal conduit est un acteur que la province a gâté. Les divers états de l'âme sont donc toujours corrélatifs à ceux du corps. Mais, pour mieux démontrer toute cette dépendance et ses causes, servons-nous ici de l'anatomie comparée; ouvrons les entrailles de l'homme et des animaux. Le moyen de connaître la nature humaine, si l'on n'est éclairé par un juste parallèle de la structure des uns et des autres! En général, la forme et la composition du cerveau des quadrupèdes est à peu près la même que dans l'homme. Même figure, même disposition partout; avec cette différence essentielle, que l'homme est de tous les animaux celui qui a le plus de cerveau, et le cerveau le plus tortueux, en raison de la masse de son corps. Ensuite le singe, le castor, l'éléphant, le chien, le renard, le chat, etc., voilà les animaux qui ressemblent le plus à l'homme; car on remarque aussi chez eux la même analogie graduée, par rapport au corps calleux, dans lequel Lancisi avait établi le siège de l'âme, avant feu Mr. de la Peyronnie, qui cependant a illustré cette opinion par une foule d'expériences. Après tous les quadrupèdes, ce sont les oiseaux qui ont le plus de cerveau. Les poissons ont la tête grosse; mais elle est vide de sens, comme celle de bien des hommes. Ils n'ont point de corps calleux et fort peu de cerveau, lequel manque aux insectes. Je ne me répandrai point en un plus long détail des variétés de la nature, ni en conjectures, car les unes et les autres sont infinies, comme on en peut juger en lisant les seuls traités de Willis, De Cerebro, et De Anima Brutorum. Je conclûrai seulement ce qui s'en suit clairement de ces incontestables observations: 1o que plus les animaux sont farouches, moins ils ont de cerveau; 2o que ce viscère semble s'agrandir, en quelque sorte, à proportion de leur docilité; 3o qu'il y a ici une singulière condition imposée éternellement par la nature, qui est que plus on gagnera du côté de l'esprit, plus on perdra du côté de l'instinct. Lequel l'emporte, de la perte ou du gain? Ne croyez pas, au reste, que je veuille prétendre par là que le seul volume du cerveau suffise pour faire juger du degré de docilité des animaux; il faut que la qualité réponde encore à la quantité, et que les solides et les fluides soient dans cet équilibre convenable qui fait la santé. Si l'imbécile ne manque pas de cerveau, comme on le remarque ordinairement, ce viscère péchera par une mauvaise consistance, par trop de mollesse, par exemple. Il en est de même des fous; les vices de leur cerveau ne se dérobent pas toujours à nos recherches; mais si les causes de l'imbécilité, de la folie, etc. ne sont pas sensibles, où aller chercher celles de la variété de tous les esprits? Elles échapperaient aux yeux des lynx et des argus. Un rien, une petite fibre, quelque chose que la plus subtile anatomie ne peut découvrir, eut fait deux sots d'Erasme et de Fontenelle, qui le remarque lui même dans un de ses meilleurs Dialogues. Outre la mollesse de la moëlle du cerveau, dans les enfants, dans les petits chiens et dans les oiseaux, Willis a remarqué que les corps cannelés sont effacés et comme décolorés dans tous ces animaux, et que leurs stries sont aussi imparfaitement formées que dans les paralytiques. Il ajoute, ce qui est vrai, que l'homme a la protubérance annulaire fort grosse; et ensuite toujours diminutivement par dégrés, le singe et les autres animaux nommés ci-devant, tandis que le veau, le boeuf, le loup, la brebis, le cochon, etc. qui ont cette partie d'un très petit volume, ont les nattes et testes fort gros. On a beau être discret et réservé sur les conséquences qu'on peut tirer de ces observations et de tant d'autres sur l'espèce d'inconstance des vaisseaux et des nerfs, etc.: tant de variétés ne peuvent être des jeux gratuits de la nature. Elles prouvent du moins la nécessité d'une bonne et abondante organisation, puisque dans tout le règne animal l'âme, se raffermissant avec le corps, acquiert de la sagacité, à mesure qu'il prend des forces. Arrêtons-nous à contempler la différente docilité des animaux. Sans doute l'analogie la mieux entendue conduit l'esprit à croire que les causes dont nous avons fait mention produisent toute la diversité qui se trouve entr'eux et nous, quoiqu'il faille avouer que notre faible entendement, borné aux observations les plus grossières, ne puisse voir les liens qui règnent entre la cause et les effets. C'est une espèce d'harmonie que les philosophes ne connaîtront jamais. Parmi les animaux, les uns apprennent à parler et à chanter; ils retiennent des airs et prennent tous les tons aussi exactement qu'un musicien. Les autres, qui montrent cependant plus d'esprit, tels que le singe, n'en peuvent venir à bout. Pourquoi cela, si ce n'est par un vice des organes de la parole? Mais ce vice est-il tellement de conformation, qu'on n'y puisse apporter aucun remède? en un mot serait-il absolument impossible d'apprendre une langue à cet animal? Je ne le crois pas. Je prendrais le grand singe préférablement à tout autre, jusqu'à ce que le hasard nous eût fait découvrir quelque autre espèce plus semblable à la nôtre, car rien ne répugne qu'il y en ait dans des régions qui nous sont inconnues. Cet animal nous ressemble si fort, que les naturalistes l'ont appelé homme sauvage, ou homme des bois. Je le prendrais aux mêmes conditions des écoliers d'Amman; c'est-à-dire, que je voudrais qu'il ne fût ni trop jeune ni trop vieux; car ceux qu'on nous apporte en Europe sont communément trop âgés. Je choisirais celui qui aurait la physionomie la plus spirituelle, et qui tiendrait le mieux dans mille petites opérations ce qu'elle m'aurait promis. Enfin, ne me trouvant pas digne d'être son gouverneur, je le mettrais à l'école de l'excellent maître que je viens de nommer, ou d'un autre aussi habile, s'il en est. Vous savez par le livre d'Amman, et par tous ceux [3] qui ont traduit sa méthode, tous les prodiges qu'il a su opérer sur les sourds de naissance, dans les yeux desquels il a, comme il le fait entendre lui-même, trouvé des oreilles; et en combien peu de temps enfin il leur a appris à entendre, parler, lire, et écrire. Je veux que les yeux d'un sourd voient plus clair et soient plus intelligents que s'il ne l'était pas, par la raison que la perte d'un membre ou d'un sens peut augmenter la force ou la pénétration d'un autre: mais le singe voit et entend; il comprend ce qu'il entend et ce qu'il voit; il conçoit si parfaitement les signes qu'on lui fait, qu'à tout autre jeu, ou tout autre exercice, je ne doute point qu'il ne l'emportât sur les disciples d'Amman. Pourquoi donc l'éducation des singes serait-elle impossible? Pourquoi ne pourrait-il enfin, à force de soins, imiter, à l'exemple des sourds, les mouvemens nécessaires pour prononcer? Je n'ose décider si les organes de la parole du singe ne peuvent, quoiqu'on fasse, rien articuler; mais cette impossibilité absolue me surprendrait, à cause de la grande analogie du singe et de l'homme, et qu'il n'est point d'animal connu jusqu'à présent, dont le dedans et le dehors lui ressemblent d'une manière si frappante. Mr. Locke, qui certainement n'a jamais été suspect de crédulité, n'a pas fait difficulté de croire l'histoire que le Chevalier Temple fait dans ses Mémoires, d'un perroquet qui répondait à propos et avait appris, comme nous, à avoir une espèce de conversation suivie. Je sais qu'on s'est moqué [4] de ce grand métaphysicien; mais qui aurait annoncé à l'univers qu'il y a des générations qui se font sans oeufs et sans femmes, aurait-il trouvé beaucoup de partisans? Cependant Mr. Trembley en a découvert, qui se font sans accouplement, et par la seule section. Amman n'eût-il pas aussi passé pour un fou, s'il se fût vanté, avant que d'en faire l'heureuse expérience, d'instruire, et en aussi peu de temps, des écoliers tels que les siens? Cependant ses succès ont étonné l'univers, et comme l'auteur de l'Histoire des Polypes, il a passé de plein vol à l'immortalité. Qui doit à son génie les miracles qu'il opère, l'emporte à mon gré sur qui doit les siens au hasard. Qui a trouvé l'art d'embellir le plus beau des règnes, et de lui donner des perfections qu'il n'avait pas, doit être mis au-dessus d'un faiseur oisif de systèmes frivoles, ou d'un auteur laborieux de stériles découvertes. Celles d'Amman sont bien d'un autre prix; il a tiré les hommes de l'instinct auquel ils semblaient condamnés; il leur a donné les idées, de l'esprit, une âme en un mot, qu'ils n'eûssent jamais eue. Quel plus grand pouvoir! Ne bornons point les ressources de la nature; elles sont infinies, surtout aidées d'un grand art. La même mécanique, qui ouvre le canal d'Eustachi dans les sourds, ne pourrait-il le déboucher dans les singes? Une heureuse envie d'imiter la prononciation du maître, ne pourrait-elle mettre en liberté les organes de la parole, dans les animaux qui imitent tant d'autres signes, avec tant d'adresse et d'intelligence? Non seulement je défie qu'on me cite aucune expérience vraiment concluante, qui décide mon projet impossible et ridicule; mais la similitude de la structure et des opérations du singe est telle, que je ne doute presque point, si on exerçait parfaitement cet animal, qu'on ne vînt enfin à bout de lui apprendre à prononcer, et par conséquent à savoir une langue. Alors ce ne serait plus ni un homme sauvage, ni un homme manqué: ce serait un homme parfait, un petit homme de ville, avec autant d'étoffe ou de muscles que nous-mêmes, pour penser et profiter de son éducation. Des animaux à l'homme, la transition n'est pas violente; les vrais philosophes en conviendront. Qu'était l'homme, avant l'invention des mots et la connaissance des langues? Un animal de son espèce, qui avec beaucoup moins d'instinct naturel que les autres, dont alors il ne se croyait pas roi, n'était distingué du singe et des autres animaux que comme le singe l'est lui-même; je veux dire par une physionomie qui annonçait plus de discernement. Réduit à la seule connaissance intuitive des Leibniziens, il ne voyait que des figures et des couleurs, sans pouvoir rien distinguer entr'elles; vieux, comme jeune, enfant à tout âge, il bégayait ses sensations et ses besoins, comme un chien affamé, ou ennuyé de repos, demande à manger ou à se promener. Les mots, les langues, les lois, les sciences, les beaux-arts sont venus; et par eux enfin le diamant brut de notre esprit a été poli. On a dressé un homme, comme un animal; on est devenu auteur, comme portefaix. Un géomètre a appris à faire les démonstrations et les calculs les plus difficiles, comme un singe à ôter ou mettre son petit chapeau, et à monter sur son chien docile. Tout s'est fait par les signes; chaque espèce a compris ce qu'elle a pu comprendre: et c'est de cette manière que les hommes ont acquis la connaissance symbolique, ainsi nommée encore par nos philosophes d'Allemagne. Rien de si simple, comme on voit, que la mécanique de notre éducation! Tout se réduit à des sons, ou à des mots, qui de la bouche de l'un passent par l'oreille de l'autre dans le cerveau, qui reçoit en même temps par les yeux la figure des corps, dont ces mots sont les signes arbitraires. Mais qui a parlé le premier? Qui a été le premier précepteur du genre human? Qui a inventé les moyens de mettre à profit la docilité de notre organisation? Je n'en sais rien; le nom de ces heureux et premiers génies a été perdu dans la nuit des temps. Mais l'art est le fils de la nature; elle a dû longtemps le précéder. On doit croire que les hommes les mieux organisés, ceux pour qui la nature aura épuisé ses bienfaits, auront instruit les autres. Ils n'auront pu entendre un bruit nouveau, par exemple, éprouver de nouvelles sensations, être frappé de tous ces beaux objets divers qui forment le ravissant spectacle de la nature, sans se trouver dans le cas de ce sourd de Chartres dont le grand Fontenelle nous a le premier donné l'histoire, lorsqu'il entendit pour la première fois à quarante ans le bruit étonnant des cloches. De là serait-il absurde de croire que ces premiers mortels essayèrent à la manière de ce sourd, ou à celle des animaux et des muets (autre espèce d'animaux), d'exprimer leurs nouveaux sentiments par des mouvements dépendants de l'économie de leur imagination, et conséquemment ensuite par des sons spontanés propres à chaque animal, expression naturelle de leur surprise, de leur joie, de leurs transports, ou de leurs besoins? Car sans doute ceux que la nature a doués d'un sentiment plus exquis, ont eu aussi plus de facilité pour l'exprimer. Voilà comme je conçois que les hommes ont employé leur sentiment, ou leur instinct, pour avoir de l'esprit, et enfin leur esprit, pour avoir des connaissances. Voilà par quels moyens, autant que je puis les saisir, on s'est rempli le cerveau des idées, pour le réception desquelles la nature l'avait formé. On s'est aidé l'un par l'autre; et les plus petits commencements s'agrandissant peu à peu, toutes les choses de l'univers ont été aussi facilement distinguées qu'un cercle. Comme une corde de violon ou une touche de clavecin frémit et rend un son, les cordes du cerveau, frappées par les rayons sonores, ont été excitées à rendre ou à redire les mots qui les touchaient. Mais comme telle est la construction de ce viscère, que dès qu'une fois les yeux bien formés pour l'optique ont reçu la peinture des objets, le cerveau ne peut pas ne pas voir leurs images et leurs différences: de même, lorsque les signes de ces différences ont été marqués, ou gravés dans le cerveau, l'âme en a nécessairement examiné les rapports; examen qui lui était impossible sans la découverte des signes, ou l'invention des langues. Dans ces temps, où l'univers était presque muet, l'âme était à l'égard de tous les objets, comme un homme qui, sans avoir aucune idée des proportions, regarderait un tableau, ou une pièce de sculpture: il n'y pourrait rien distinguer; ou comme un petit enfant (car alors l'âme était dans son enfance) qui, tenant dans sa main un certain nombre de petits brins de paille ou de bois, les voit en général d'une vue vague et superficielle, sans pouvoir les compter ni les distinguer. Mais qu'on mette une espèce de pavillon, ou d'étendard, à cette pièce de bois, par exemple, qu'on appelle mât, qu'on en mette un autre à un autre pareil corps; que le premier venu se nombre par le signe 1 et le second par le signe ou chiffre 2; alors cet enfant pourra les compter, et ainsi de suite il apprendra toute l'arithmétique. Dès qu'une figure lui paraîtra égale à une autre par son signe numératif, il conclûra sans peine que ce sont deux corps différents; que 1 et 1 font deux, que 2 et 2 font 4, [5] etc. C'est cette similitude réelle, ou apparente, des figures, qui est la base fondamentale de toutes les vérités et de toutes nos connaissances, parmi lesquelles il est évident que celles dont les signes sont moins simples et moins sensibles sont plus difficiles à apprendre que les autres, en ce qu'elles demandent plus de génie pour embrasser et combiner cette immense quantité de mots par lesquels les sciences dont je parle expriment les vérités de leur ressort: tandis que les sciences qui s'annoncent par des chiffres, ou autres petits signes, s'apprennent facilement; et c'est sans doute cette facilité qui a fait la fortune des calculs algébriques, plus encore que leur évidence. Tout ce savoir dont le vent enfle le ballon du cerveau de nos pédants orgueilleux, n'est donc qu'un vaste amas de mots et de figures, qui forment dans la tête toutes les traces par lesquelles nous distinguons et nous nous rappellons les objets. Toutes nos idées se réveillent, comme un jardinier qui connaît les plantes se souvient de toutes leurs phases à leur aspect. Ces mots et ces figures qui sont désignés par eux, sont tellements liés ensemble dans le cerveau, qu'il est assez rare qu'on imagine une chose sans le nom ou le signe qui lui est attaché. Je me sers toujours du mot imaginer, parceque je crois que tout s'imagine, et que toutes les parties de l'âme peuvent être justement réduites à la seule imagination, qui les forme toutes; et qu'ainsi le jugement, le raisonnement, la mémoire ne sont que des parties de l'âme nullement absolues, mais de véritables modifications de cette espèce de toile médullaire, sur laquelle les objets peints dans l'oeil sont renvoyés, comme d'une lanterne magique. Mais si tel est ce merveilleux et incompréhensible résultat de l'organisation du cerveau; si tout se conçoit par l'imagination, si tout s'explique par elle; pourquoi diviser le principe sensitif qui pense dans l'homme? N'est-ce pas une contradiction manifeste dans les partisans de la simplicité de l'esprit? Car une chose qu'on divise ne peut plus être, sans absurdité, regardée comme indivisible. Voilà où conduit l'abus des langues, et l'usage de ces grands mots, spiritualité, immatérialité, etc., placés à tout hasard, sans être entendus, même par des gens d'esprit. Rien de plus facile que de prouver un système, fondé comme celui-ci sur le sentiment intime et l'expérience propre de chaque individu. L'imagination, ou cette partie fantastique du cerveau, dont la nature nous est aussi inconnue que sa manière d'agir, est-elle naturellement petite, ou faible? elle aura à peine la force de comparer l'analogie, ou la ressemblance de ses idées; elle ne pourra voir que ce qui sera vis-à-vis d'elle, ou ce qui l'affectera le plus vivement; et encore de quelle manière! Mais toujours est-il vrai que l'imagination seule aperçoit; que c'est elle qui se représente tous les objets, avec les mots et les figures qui les caractérisent; et qu'ainsi c'est elle encore une fois qui est l'âme, puisqu'elle en fait tous les rôles. Par elle, par son pinceau flatteur, le froid squelette de la raison prend des chairs vives et vermeilles; par elle les sciences fleurissent, les arts s'embellissent, les bois parlent, les échos soupirent, les rochers pleurent, le marbre respire, tout prend vie parmi les corps inanimés. C'est elle encore qui ajoute à la tendresse d'un coeur amoureux le piquant attrait de la volupté; elle la fait germer dans le cabinet du philosophe, et du pédant poudreux; elle forme enfin les savants comme les orateurs et les poëtes. Sottement décriée par les uns, vainement distinguée par les autres, qui tous l'ont mal connue, elle ne marche pas seulement à la suite des Grâces et des beaux-art, elle ne peint pas seulement la nature, elle peut aussi la mesurer. Elle raisonne, juge, pénètre, compare, approfondit. Pourrait-elle si bien sentir les beautées des tableaux qui lui sont tracés, sans en découvrir les rapports? Non; comme elle ne peut se replier sur les plaisirs des sens, sans en goûter toute la perfection ou la volupté, elle ne peut réfléchir sur ce qu'elle a mécaniquement conçu, sans être alors le jugement même. Plus on exerce l'imagination, ou le plus maigre génie, plus il prend, pour ainsi dire, d'embonpoint; plus il s'agrandit, devient nerveux, robuste, vaste et capable de penser. La meilleure organisation a besoin de cet exercice. L'organisation est le premier mérite de l'homme; c'est en vain que tous les auteurs de morale ne mettent point au rang des qualités estimables celles qu'on tient de la nature, mais seulement les talents qui s'acquièrent à force de réflexions et d'industrie: car d'où nous vient, je vous prie, l'habileté, la science et la vertu, si ce n'est d'une disposition qui nous rend propres à devenir habiles, savants et vertueux? Et d'où nous vient encore cette disposition, si ce n'est de la nature? Nous n'avons de qualités estimables que par elle; nous lui devons tout ce que nous sommes. Pourquoi donc n'estimerais-je pas autant ceux qui ont des qualités naturelles, que ceux qui brillent par des vertus acquises, et comme d'emprunt? Quel que soit le mérite, de quelque endroit qu'il naisse, il est digne d'estime; il ne s'agit que de savoir le mesurer. L'esprit, la beauté, les richesses, la noblesse, quoiqu'enfants du hasard, ont tous leur prix, comme l'adresse, le savoir, la vertu, etc. Ceux que la nature a comblés de ses dons les plus précieux, doivent plaindre ceux à qui ils ont été refusés; mais ils peuvent sentir leur supériorité sans orgueil, et en connaisseurs. Une belle femme serait aussi ridicule de se trouver laide, qu'un homme d'esprit de se croire un sot. Une modestie outrée (défaut rare à la vérité) est une sorte d'ingratitude envers la nature. Une honnête fierté, au contraire, est la marque d'une âme belle et grande, que décèlent des traits mâles moulés comme par le sentiment. Si l'organisation est un mérite, et le premier mérite, et la source de tous les autres, l'instruction est le second. Le cerveau le mieux construit, sans elle, le serait en pure perte; comme sans l'usage du monde, l'homme le mieux fait ne serait qu'un paysan grossier. Mais aussi quel serait le fruit de la plus excellente école, sans une matrice parfaitement ouverte à l'entrée ou à la conception des idées? Il est aussi impossible de donner une seule idée à un homme privé de tous les sens, que de faire un enfant à une femme à laquelle la nature aurait poussé la distraction jusqu'à oublier de faire une vulve, comme je l'ai vu dans une, qui n'avait ni fente, ni vagin, ni matrice, et qui pour cette raison fut démariée après dix ans de mariage. Mais si le cerveau est à la fois bien organisé et bien instruit, c'est une terre féconde parfaitement ensemencée, qui produit le centuple de ce qu'elle a reçu: ou (pour quitter le style figuré souvent nécessaire, pour mieux exprimer ce qu'on sent et donner des grâces à la Vérité même), l'imagination élevée par l'art à la belle et rare dignité de génie, saisit exactement tous les rapports des idées qu'elle a conçues, embrasse avec facilité une foule étonnante d'objets, pour en tirer enfin une longue chaîne de conséquences, lesquelles ne sont encore que de nouveaux rapports, enfantés par la comparaison des premiers, auxquels l'âme trouve une parfaite ressemblance. Telle est, selon moi, la génération de l'esprit. Je dis trouve, comme j'ai donné ci-devant l'épithète d'apparente à la similitude des objets: non que je pense que nos sens soient toujours trompeurs, comme l'a prétendu le Père Malebranche, ou que nos yeux naturellement un peu ivres ne voient pas les objets tels qu'ils sont en eux mêmes, quoique les microscopes nous le prouvent tous les jours, mais pour n'avoir aucune dispute avec les Pyrrhoniens, parmi lesquels Bayle s'est distingué. Je dis de la vérité en général ce que Mr. de Fontenelle dit de certaines en particulier, qu'il faut la sacrifier aux agréments de la société. Il est de la douceur de mon caractère d'obvier à toute dispute, lorsqu'il ne s'agit pas d'aiguiser la conversation. Les Cartésiens viendraient ici vainement à la charge avec leur idées innées; je ne me donnerais certainement pas le quart de la peine qu'a prise Mr. Locke pour attaquer de telles chimères. Quelle utilité, en effet, de faire un gros livre, pour prouver une doctrine qui était érigée en axiome il y a trois mille ans? Suivant les principes que nous avons posés, et que nous croyons vrais, celui qui a le plus d'imagination doit être regardé comme ayant le plus d'esprit, ou de génie, car tous ces mots sont synonymes; et encore une fois c'est par un abus honteux qu'on croit dire des choses différentes, lorsqu'on ne dit que différents mots ou différents sons, auxquels on n'a attaché aucune idée ou distinction réelle. La plus belle, la plus grande, ou la plus forte imagination, est donc la plus propre aux sciences, comme aux arts. Je ne décide point s'il faut plus d'esprit pour exceller dans l'art des Aristotes, ou des Descartes, que dans celui des Euripides ou des Sophocles; et si la nature s'est mise en plus grands frais pour faire Newton que pour former Corneille (ce dont je doute fort), mais il est certain que c'est la seule imagination diversement appliquée qui a fait leur différent triomphe et leur gloire immortelle. Si quelqu'un passe pour avoir peu de jugement, avec beaucoup d'imagination; cela veut dire que l'imagination trop abandonnée à elle même, presque toujours comme occupée à se regarder dans le miroir de ses sensations, n'a pas assez contracté l'habitude de les examiner elles-mêmes avec attention; plus profondément pénétrée des traces, ou des images, que de leur vérité ou de leur ressemblance. Il est vrai que telle est la vivacité des ressorts de l'imagination, que si l'attention, cette clé ou mère des sciences, ne s'en mêle, il ne lui est guères permis que de parcourir et d'effleurer les objets. Voyez cet oiseau sur la branche, il semble toujours prêt à s'envoler; l'imagination est de même. Toujours emportée par le tourbillon du sang et des esprits, une onde fait une trace, effacée par celle qui suit; l'âme court après, souvent en vain: il faut qu'elle s'attende à regretter ce qu'elle n'a pas assez vite saisi et fixé: et c'est ainsi que l'imagination, véritable image du temps, se détruit et se renouvelle sans cesse. Tel est le chaos et la succession continuelle et rapide de nos idées; elles se chassent, comme un flot pousse l'autre; de sorte que si l'imagination n'emploie, pour ainsi dire, une partie de ses muscles pour être comme en équilibre sur les cordes du cerveau, pour se soutenir quelque temps sur un objet qui va fuir et s'empêcher de tomber sur un autre, qu'il n'est pas encore temps de contempler, jamais elle ne sera digne du beau nom de jugement. Elle exprimera vivement ce qu'elle aura senti de même; elle formera des orateurs, des musiciens, des peintres, des poètes, et jamais un seul philosophe. Au contraire si, dès l'enfance, on accoutume l'imagination à se brider elle-même, à ne point se laisser emporter à sa propre impétuosité, qui ne fait que de brillants enthousiastes, à arrêter, contenir ses idées, à les retourner dans tous les sens, pour voir toutes les faces d'un objet, alors l'imagination prompte à juger embrassera par le raisonnement la plus grande sphère d'objets, et sa vivacité, toujours de si bon augure dans les enfants, et qu'il ne s'agit que de régler par l'étude et l'exercice, ne sera plus qu'une pénétration clairvoyante, sans laquelle on fait peu de progrès dans les sciences. Tels sont les simples fondements sur lesquels a été bati l'édifice de la logique. La nature les avait jetés pour tout le genre humain; mais les uns en ont profité, les autres en ont abusé. Malgré toutes ces prérogatives de l'homme sur les animaux, c'est lui faire honneur que de le ranger dans la même classe. Il est vrai que, jusqu'à un certain âge, il est plus animal qu'eux, parce qu'il apporte moins d'instinct en naissant. Quel est l'animal qui mourrait de faim au milieu d'une rivière de lait? L'homme seul. Semblable à ce vieux enfant dont un moderne parle d'après Arnobe, il ne connait ni les aliments qui lui sont propres, ni l'eau qui peut le noyer, ni le feu qui peut le réduire en poudre. Faites briller pour la première fois la lumière d'une bougie aux yeux d'un enfant, il y portera machinalement le doigt, comme pour savoir quel est le nouveau phénomène qu'il aperçoit; c'est à ses dépens qu'il en connaîtra le danger, mais il n'y sera pas repris. Mettez-le encore avec un animal sur le bord d'un précipice! lui seul y tombera; il se noie, où l'autre se sauve à la nage. A quatorze ou quinze ans, il entrevoit à peine les grands plaisirs qui l'attendent dans la reproduction de son espèce; déjà adolescent, il ne sait pas trop comment s'y prendre dans un jeu que la nature apprend si vite aux animaux: il se cache, comme s'il était honteux d'avoir du plaisir et d'être fait pour être heureux, tandis que les animaux se font gloire d'être cyniques. Sans éducation, ils sont sans préjugés. Mais voyons encore ce chien et cet enfant qui ont tous deux perdu leur maître dans un grand chemin: l'enfant pleure, il ne sait à quel saint se vouer; le chien, mieux servi par son odorat que l'autre par sa raison, l'aura bientôt trouvé. La nature nous avait donc faits pour être au dessous des animaux, ou du moins pour faire par là même mieux éclater les prodiges de l'éducation, qui seule nous tire du niveau et nous élève enfin au-dessus d'eux. Mais accordera-t-on la même distinction aux sourds, aux aveugles-nés, aux imbéciles, aux fous, aux hommes sauvages, ou qui ont été élevés dans les bois avec les bêtes, à ceux dont l'affection hypocondriaque a perdu l'imagination, enfin à toutes ces bêtes à figure humaine, qui ne montrent que l'instinct le plus grossier? Non, tous ces hommes de corps, et non d'esprit, ne méritent pas une classe particulière. Nous n'avons pas dessein de nous dissimuler les objections qu'on peut faire en faveur de la distinction primitive de l'homme et des animaux, contre notre sentiment. Il y a, dit-on, dans l'homme une loi naturelle, une connaissance du bien et du mal, qui n'a pas été gravée dans le coeur des animaux. Mais cette objection, ou plutôt cette assertion est-elle fondée sur l'expérience, sans laquelle un philosophe peut tout rejeter? En avons-nous quelqu'une qui nous convainque que l'homme seul a été éclairé d'un rayon refusé à tous les autres animaux? S'il n'y en a point, nous ne pouvons pas plus connaître par elle ce qui se passe dans eux, et même dans les hommes, que ne pas sentir ce qui affecte l'intérieur de notre être. Nous savons que nous pensons et que nous avons des remords: un sentiment intime ne nous force que trop d'en convenir; mais pour juger des remords d'autrui, ce sentiment qui est dans nous est insuffisant: c'est pourquoi il en faut croire les autres hommes sur leur parole, ou sur les signes sensibles et extérieurs que nous avons remarqués en nous-mêmes, lorsque nous éprouvions la même conscience et les mêmes tourments. Mais pour décider si les animaux qui ne parlent point ont reçu la loi naturelle, il faut s'en rapporter conséquemment à ces signes dont je viens de parler, supposé qu'ils existent. Les faits semblent le prouver. Le chien qui a mordu son maître qui l'agaçait, a paru s'en repentir le moment suivant; on l'a vu triste, fâché, n'osant se montrer, et s'avouer coupable par un air rampant et humilié. L'histoire nous offre un exemple célèbre d'un lion qui ne voulut pas déchirer un homme abandonné à sa fureur, parce qu'il le reconnut pour son bienfaiteur. Qu'il serait à souhaiter que l'homme même montrât toujours la même reconnaissance pour les bienfaits et le même respect pour l'humanité! On n'aurait plus à craindre les ingrats, ni ces guerres qui sont le fléau du genre humain et les vrais bourreaux de la loi naturelle. Mais un être à qui la nature a donné un instinct si précoce, si éclairé, qui juge, combine, raisonne et délibère, autant que s'étend et le lui permet la sphère de son activité; un être qui s'attache par les bienfaits, qui se détache par les mauvais traitements et va essayer un meilleur maître; un être d'une structure semblable à la nôtre, qui fait les mêmes opérations, qui a les mêmes passions, les mêmes douleurs, les mêmes plaisirs, plus ou moins vifs suivant l'empire de l'imagination et la délicatesse des nerfs; un tel être enfin ne montre-t-il pas clairement qu'il sent ses torts et les nôtres, qu'il connait le bien et le mal et, en un mot, a conscience de ce qu'il fait? Son âme qui marque comme la nôtre les mêmes joies, les mêmes mortifications, les mêmes déconcertements, serait-elle sans aucune répugnance à la vue de son semblable déchiré, ou après l'avoir lui-même impitoyablement mis en pièces? Cela posé, le don précieux dont il s'agit n'aurait point été refusé aux animaux; car puisqu'ils nous offrent des signes évidents de leur repentir, comme de leur intelligence, qu'y a-t-il d'absurde à penser que des êtres, des machines presque aussi parfaites que nous, soient, comme nous, faites pour penser et pour sentir la nature? Qu'on ne m'objecte point que les animaux sont pour la plupart des êtres féroces, qui ne sont pas capables de sentir les maux qu'ils font; car tous les hommes distinguent-ils mieux les vices et les vertus? Il est dans notre espèce de la férocité, comme dans la leur. Les hommes qui sont dans la barbare habitude d'enfreindre la loi naturelle, n'en sont pas si tourmentés que ceux qui la transgressent pour la première fois, et que la force de l'exemple n'a point endurcis. Il en est de même des animaux, comme des hommes. Les uns et les autres peuvent être plus ou moins féroces par tempérament, et ils le deviennent encore plus avec ceux qui le sont. Mais un animal doux, pacifique, qui vit avec d'autres animaux semblables, et d'aliments doux, sera ennemi du sang et du carnage, il rougira intérieurement de l'avoir versé; avec cette différence peut-être que, comme chez eux tout est immolé aux besoins, aux plaisirs et aux commodités de la vie, dont ils jouissent plus que nous, leurs remords ne semblent pas devoir être si vifs que les nôtres, parceque nous ne sommes pas dans la même nécessité qu'eux. La coutume émousse et peut-être étouffe les remords, comme les plaisirs. Mais je veux pour un moment supposer que je me trompe, et qu'il n'est pas juste que presque tout l'univers ait tort à ce sujet, tandis que j'aurais seul raison; j'accorde que les animaux, même les plus excellents, ne connaissent pas la distinction du bien et du mal moral, qu'ils n'ont aucune mémoire des attentions qu'on a eues pour eux, du bien qu'on leur a fait, aucun sentiment de leurs propres vertus; que ce lion, par exemple, dont j'ai parlé après tant d'autres, ne se souvienne pas de n'avoir pas voulu ravir la vie à cet homme qui fut livré à sa furie, dans un spectacle plus inhumain que tous les lions, les tigres et les ours; tandis que nos compatriotes se battent, Suisses contre Suisses, frères contre frères, se reconnaissent, s'enchaînent, ou se tuent sans remords, parce qu'un prince paie leurs meurtres: je suppose enfin que la loi naturelle n'ait pas été donnée aux animaux, quelles en seront les conséquences? L'homme n'est pas pétri d'un limon plus précieux; la nature n'a employé qu'une seule et même pâte, dont elle a seulement varié les levains. Si donc l'animal ne se repent pas d'avoir violé le sentiment intérieur dont je parle, ou plutôt s'il en est absolument privé, il faut nécessairement que l'homme soit dans le même cas: moyennant quoi adieu la loi naturelle et tous ces beaux traités qu'on a publiés sur elle! Tout le règne animal en serait généralement dépourvû. Mais réciproquement si l'homme ne peut se dispenser de convenir qu'il distingue toujours, lorsque la santé le laisse jouïr de lui-même, ceux qui ont de la probité, de l'humanité, de la vertu, de ceux qui ne sont ni humains, ni vertueux, ni honnêtes gens; qu'il est facile de distinguer ce qui est vice, ou vertu, par l'unique plaisir ou la propre répugnance qui en sont comme les effets naturels, il s'ensuit que les animaux formés de la même matière, à laquelle il n'a peut-être manqué qu'un degré de fermentation pour égaler les hommes en tout, doivent participer aux mêmes prérogatives de l'animalité, et qu'ainsi il n'est point d'âme, ou de substance sensitive, sans remords. La réflexion suivante va fortifier celles-ci. On ne peut détruire la loi naturelle. L'empreinte en est si forte dans tous les animaux, que je ne doute nullement que les plus sauvages et les plus féroces n'aient quelques moments de repentir. Je crois que la fille sauvage de Châlons en Champagne aura porté la peine de son crime, s'il est vrai qu'elle ait mangé sa soeur. Je pense la même chose de tous ceux qui commettent des crimes, même involontaires, ou de tempérament: de Gaston d'Orléans qui ne pouvait s'empêcher de voler; de certaine femme qui fut sujette au même vice dans la grossesse, et dont ses enfants héritèrent; de celle qui dans le même état, mangea son mari; de cette autre qui égorgeait les enfants, salait leurs corps, et en mangeait tous les jours comme du petit salé; de cette fille de voleur anthropophage, qui la devint à 12 ans, quoiqu'ayant perdu père et mère à l'âge d'un an elle eût été élevée par d'honnêtes gens, pour ne rien dire de tant d'autres exemples dont nos observateurs sont remplis, et qui prouvent tous qu'il est mille vices et vertus héréditaires, qui passent des parents aux enfants, comme ceux de la nourrice à ceux qu'elle allaite. Je dis donc et j'accorde que ces malheureux ne sentent pas pour la plupart sur le champ l'énormité de leur action. La boulimie, par exemple, ou la faim canine, peut éteindre tout sentiment; c'est une manie d'estomac qu'on est forcé de satisfaire. Mais revenues à elles-mêmes, et comme désenivrées, quels remords pour ces femmes qui se rappellent le meurtre qu'elles ont commis dans ce qu'elles avaient de plus cher! quelle punition d'un mal involontaire, auquel elles n'ont pu résister, dont elles n'ont eu aucune conscience! Cependant ce n'est point assez apparemment pour les juges. Parmi les femmes dont je parle, l'une fut rouée, et brûlée, l'autre enterrée vive. Je sens tout ce que demande l'intérêt de la société. Mais il serait sans doute à souhaiter qu'il n'y eût pour juges que d'excellents médecins. Eux seuls pourraient distinguer le criminel innocent, du coupable. Si la raison est esclave d'un sens dépravé, ou en fureur, comment peut-elle le gouverner? Mais si le crime porte avec soi sa propre punition plus ou moins cruelle; si la plus longue et la plus barbare habitude ne peut tout-à-fait arracher le repentir des coeurs les plus inhumains; s'ils sont déchirés par la mémoire même de leurs actions; pour quoi effrayer l'imagination des esprits faibles par un enfer, par des spectres, et des précipices de feu, moins réels encore que ceux de Pascal [6]? Qu'est-il besoin de recourir à des fables, comme un pape de bonne foi l'a dit lui-même, pour tourmenter les malheureux mêmes qu'on fait périr, parce qu'on ne les trouve pas assez punis par leur propre conscience, qui est leur premier bourreau? Ce n'est pas que je veuille dire que tous les criminels soient injustement punis; je prétends seulement que ceux dont la volonté est dépravée, et la conscience éteinte, le sont assez par leurs remords, quand ils reviennent à eux-mêmes; remords, j'ose encore le dire, dont la nature aurait dû en ce cas, ce me semble, délivrer des malheureux entraînés par une fatale nécessité. Les criminels, les méchants, les ingrats, ceux enfin que ne sentent pas la nature, tyrans malheureux et indignes du jour, ont beau se faire un cruel plaisir de leur barbarie, il est des moments calmes et de réflexion, où la conscience vengeresse s'élève, dépose contr'eux, et les condamne à être presque sans cesse déchirés de ses propres mains. Qui tourmente les hommes, est tourmenté par lui-même; et les maux qu'il sentira seront la juste mesure de ceux qu'il aura faits. D'un autre côté, il y a tant de plaisir à faire du bien, à sentir, à reconnaître celui qu'on reçoit, tant de contentement à pratiquer la vertu, à être doux, humain, tendre, charitable, compatissant et généreux (ce seul mot renferme toutes les vertus), que je tiens pour assez puni quiconque a le malheur de n'être pas né vertueux. Nous n'avons pas originairement été faits pour être savants; c'est peut-être par une espèce d'abus de nos facultés organiques, que nous le sommes devenus; et cela à la charge de l'Etat, qui nourrit une multitude de fainéants, que la vanité a decorés du nom de philosophes. La nature nous a tous créés uniquement pour être heureux; oui, tous, depuis le ver qui rampe, jusqu'à l'aigle qui se perd dans la nue. C'est pourquoi elle a donné à tous les animaux quelque portion de la loi naturelle, portion plus ou moins exquise selon que le comportent les organes bien conditionnés de chaque animal. A présent, comment définirons-nous la loi naturelle? C'est un sentiment qui nous apprend ce que nous ne devons pas faire, parce que nous ne voudrions pas qu'on nous le fît. Oserais-je ajouter à cette idée commune, qu'il me semble que ce sentiment n'est qu'une espèce de crainte, ou de frayeur, aussi salutaire à l'espèce qu'a l'individu; car peut-être ne respectons-nous la bourse et la vie des autres, que pour nous conserver nos biens, notre honneur et nous-mêmes; semblables à ces Ixions du Christianisme qui n'aiment Dieu et n'embrassent tant de chimériques vertus, que parce qu'ils craignent l'enfer. Vous voyez que la loi naturelle n'est qu'un sentiment intime, qui appartient encore à l'imagination, comme tous les autres, parmi lesquels on compte la pensée. Par conséquent elle ne suppose évidemment ni éducation, ni révélation, ni législateur, à moins qu'on ne veuille la confondre avec les lois civiles, à la manière ridicule des théologiens. Les armes du fanatisme peuvent détruire ceux qui soutiennent ces vérités; mais elles ne détruiront jamais ces vérités mêmes. Ce n'est pas que je révoque en doute l'existence d'un Etre suprême; il me semble au contraire que le plus grand degré de probabilité est pour elle: mais comme cette existence ne prouve pas plus la nécessité d'un culte, que toute autre, c'est une vérité théorique, qui n'est guère d'usage dans la pratique: de sorte que, comme on peut dire, d'après tant d'expériences, que la religion ne suppose pas l'exacte probité, les mêmes raisons autorisent à penser que l'athéisme ne l'exclut pas. Qui sait d'ailleurs si la raison de l'existence de l'homme ne serait pas dans son existence même? Peut-être a-t-il été jeté au hasard sur un point de la surface de la terre, sans qu'on puisse savoir ni comment, ni pourquoi, mais seulement qu'il doit vivre et mourir, semblable à ces champignons, qui paraissent d'un jour à l'autre, ou à ces fleurs qui bordent les fossés et couvrent les murailles. Ne nous perdons point dans l'infini, nous ne sommes pas faits pour en avoir la moindre idée; il nous est absolument impossible de remonter à l'origine des choses. Il est égal d'ailleurs pour notre repos, que la matière soit éternelle, ou qu'elle ait été créée, qu'il y ait un Dieu, ou qu'il n'y en ait pas. Quelle folie de tant se tourmenter pour ce qu'il est impossible de connaître, et ce qui ne nous rendrait pas plus heureux, quand nous en viendrions à bout. Mais, dit-on, lisez tous les ouvrages des Fénelon, des Nieuventit, des Abadie, des Derham, des Raï, etc. Eh bien! que m'apprendront-ils? ou plutôt que m'ont-ils appris? Ce ne sont que d'ennuyeuses répétitions d'écrivains zélés, dont l'un n'ajoute à l'autre qu'un verbiage, plus propres à fortifier qu'à saper les fondements de l'athéisme. Le volume des preuves qu'on tire du spectacle de la nature, ne leur donne pas plus de force. La structure seule d'un doigt, d'une oreille, d'un oeil, une observation de Malpighi, prouve tout, et sans doute beaucoup mieux que Descartes et Malebranche; ou tout le reste ne prouve rien. Les déistes, et les Chrétiens mêmes devraient donc se contenter de faire observer que, dans tout le règne animal, les mêmes vues sont exécutées par une infinité de divers moyens, tous cependant exactement géométriques. Car de quelles plus fortes armes pourrait-on terrasser les athées? Il est vrai que si ma raison ne me trompe pas, l'homme et tout l'univers semblent avoir été destinés à cette unité de vues. Le soleil, l'air, l'eau, l'organisation, la forme des corps, tout est arrangé dans l'oeil, comme dans un miroir qui présente fidèlement à l'imagination les objets qui y sont peints, suivant les lois qu'exige cette infinie variété de corps qui servent à la vision. Dans l'oreille, nous trouvons partout une diversité frappante, sans que cette diverse fabrique de l'homme, des animaux, des oiseaux, des poissons, produise différents usages. Toutes les oreilles sont si mathématiquement faites, qu'elles tendent également au seul et même but, qui est d'entendre. Le hasard, demande le déiste, serait-il donc assez grand géomètre, pour varier ainsi à son gré les ouvrages dont on le suppose auteur, sans que tant de diversité pût l'empêcher d'atteindre la même fin? Il objecte encore ces parties évidemment contenues dans l'animal pour de futurs usages, le papillon dans la chenille, l'homme dans le ver spermatique, un polype entier dans chacune de ses parties, la valvule du trou ovale, le poumon dans le foetus, les dents dans leurs alvéoles, les os dans les fluides, qui s'en détachent et se durcissent d'une manière incompréhensible. Et comme les partisans de ce système, loin de rien négliger pour le faire valoir, ne se lassent jamais d'accumuler preuves sur preuves, ils veulent profiter de tout, et de la faiblesse même de l'esprit en certain cas. Voyez, disent-ils, les Spinoza, les Vanini, les Desbarreaux, les Boindin, apôtres qui font plus d'honneur que de tort au déisme! La durée de la santé de ces derniers a été la mesure de leur incrédulité: et il est rare en effet, ajoutent-ils, qu'on n'abjure pas l'athéisme, dès que les passions se sont affaiblies avec le corps qui en est l'instrument. Voilà certainement tout ce qu'on peut dire de plus favorable à l'existence d'un Dieu, quoique le dernier argument soit frivole, en ce que ces conversions sont courtes, l'esprit reprenant presque toujours ses anciennes opinions et se conduisant en conséquence, dès qu'il a recouvré ou plutôt retrouvé ses forces dans celles du corps. En voilà du moins beaucoup plus que n'en dit le médecin Diderot dans ses Pensées philosophiques, sublime ouvrage qui ne convaincra pas un athée. Que répondre en effet à un homme qui dit? "Nous ne connaissons point la nature: des causes cachées dans son sein pourraient avoir tout produit. Voyez à votre tour le polype de Trembley! ne contient-il pas en soi les causes qui donnent lieu à sa régénération? quelle absurdité y aurait-il donc à penser qu'il est des causes physiques pour lesquelles tout a été fait, et auxquelles toute la chaîne de ce vaste univers est si nécessairement liée et assujettie, que rien de ce qui arrive ne pouvait pas ne pas arriver; des causes dont l'ignorance absolument invincible nous a fait recourir à un Dieu, qui n'est pas même un être de raison, suivant certains? Ainsi, détruire le hasard, ce n'est pas prouver l'existence d'un Etre supreme, puisqu'il peut y avoir autre chose qui ne serait ni hasard, ni Dieu, je veux dire la Nature, dont l'étude par conséquent ne peut faire que des incrédules, comme le prouve la façon de penser de tous ses plus heureux scrutateurs." Le poids de l'univers n'ébranle donc pas un véritable athée, loin de l'écraser; et tous ces indices mille et mille fois rebattus d'un Créateur, indices qu'on met fort au-dessus de la façon de penser dans nos semblables, ne sont évidents, quelque loin qu'on pousse cet argument, que pour les Antipyrrhoniens, ou pour ceux qui ont assez de confiance dans leur raison pour croire pouvoir juger sur certaines apparences, auxquelles, comme vous voyez, les athées peuvent en opposer d'autres peut-être aussi fortes et absolument contraires. Car si nous écoutons encore les naturalistes, ils nous diront que les mêmes causes qui dans les mains d'un chimiste et par le hasard de divers mélanges ont fait le premier miroir, dans celles de la nature ont fait l'eau pure, qui en sert à la simple bergère: que le mouvement qui conserve le monde, a pu le créer; que chaque corps a pris la place que sa nature lui a assignée; que l'air a dû entourer la terre, par la même raison que le fer et les autres métaux sont l'ouvrage de ses entrailles; que le soleil est une production aussi naturelle, que celle de l'électricité; qu'il n'a pas plus été fait pour échauffer la terre et tous ses habitants, qu'il brûle quelquefois, que la pluie pour faire pousser les grains, qu'elle gâte souvent; que le miroir et l'eau n'ont pas plus été faits pour qu'on pût s'y regarder, que tous les corps polis qui ont la même propriété: que l'oeil est à la vérité une espèce de trumeau dans lequel l'âme peut contempler l'image des objets, tels qu'ils lui sont représentés par ces corps: mais qu'il n'est pas démontré que cet organe ait été réellement fait exprès pour cette contemplation, ni exprès placé dans l'orbite; qu'enfin il se pourrait bien faire que Lucrèce, le médecin Lamy et tous les Epicuriens anciens et modernes eûssent raison, lorsqu'ils avancent que l'oeil ne voit que par ce qu'il se trouve organisé, et placé comme il l'est, que posées une fois les mêmes règles de mouvement que suit la nature dans la génération et le développement des corps, il n'était pas possible que ce merveilleux organe fût organisé et placé autrement. Tel est le pour et le contre, et l'abrégé des grandes raisons qui partageront éternellement les philosophes. Je ne prends aucun parti. "Non nostrum inter vos tantas componere lites." C'est ce que je disais à un Français de mes amis, aussi franc Pyrrhonien que moi, homme de beaucoup de mérite, et digne d'un meilleur sort. Il me fit à ce sujet une réponse fort singulière. Il est vrai, me dit-il, que le pour et le contre ne doit point inquiéter l'âme d'un philosophe, qui voit que rien n'est démontré avec assez de clarté pour forcer son consentement, et même que les idées indicatives qui s'offrent d'un côté, sont ausitôt détruites par celles qui se montrent de l'autre. Cependant, reprit-il, l'univers ne sera jamais heureux, à moins qu'il ne soit athée. Voici quelles étaient les raisons de cet abominable homme. Si l'athéisme, disait-il, était généralement répandu, toutes les branches de la religion seraient alors détruites et coupées par la racine. Plus de guerres théologiques; plus de soldats de religion; soldats terribles! la nature infectée d'un poison sacré, reprendrait ses droits et sa pureté. Sourds à toute autre voix, les mortels tranquilles ne suivraient que les conseils spontanés de leur propre individu, les seuls qu'on ne méprise point impunément et qui peuvent seuls nous conduire au bonheur par les agréables sentiers de la vertu. Telle est la loi naturelle; quiconque en est rigide observateur, est honnête homme, et mérite la confiance de tout le genre humain. Quiconque ne la suit pas scrupuleusement, a beau affecter les spécieux dehors d'une autre religion, est un fourbe, ou un hypocrite dont je me défie. Après cela, qu'un vain peuple pense différemment; qu'il ose affirmer qu'il y va de la probité même, à ne pas croire la Révélation; qu'il faut en un mot un autre religion que celle de la nature, quelle qu'elle soit! quelle misère! quelle pitié! et la bonne opinion que chacun nous donne de celle qu'il a embrassée! Nous ne briguons point ici le suffrage du vulgaire. Qui dresse dans son coeur des autels à la superstition, est né pour adorer des idoles, et non pour sentir la vertu. Mais puisque toutes les facultés de l'âme dépendent tellement de la propre organisation du cerveau et de tout le corps, qu'elles ne sont visiblement que cette organisation même: voilà une machine bien éclairée! car enfin quand l'homme seul aurait reçu en partage la loi naturelle, en serait-il moins une machine? Des roues, quelques ressorts de plus que dans les animaux les plus parfaits, le cerveau proportionnellement plus proche du coeur, et recevant aussi plus de sang, la même raison donnée; que sais-je enfin? des causes inconnues produiraient toujours cette conscience délicate, si facile à blesser, ces remords qui ne sont pas plus étrangers à la matière que la pensée, et en un mot toute la différence qu'on suppose ici. L'organisation suffirait-elle donc a tout? oui, encore une fois. Puisque la pensée se développe visiblement avec les organes, pourquoi la matière dont ils sont faits ne serait-elle pas aussi susceptible de remords, quand une fois elle a acquis avec le temps la faculté de sentir? L'âme n'est donc qu'un vain terme dont on n'a point d'idée, et dont un bon esprit ne doit se servir que pour nommer la partie qui pense en nous. Posé le moindre principe de mouvement, les corps animés auront tout ce qu'il leur faut pour se mouvoir, sentir, penser, se repentir, et se conduire en un mot dans le physique, et dans le moral qui en dépend. Nous ne supposons rien; ceux qui croiraient que toutes les difficultés ne seraient pas encore levées, vont trouver des expériences, qui achèveront de les satisfaire. 1. Toutes les chairs des animaux palpitent après la mort, d'autant plus longtemps que l'animal est plus froid et transpire moins: les tortues, les lézards, les serpents, etc. en font foi. 2. Les muscles séparés du corps, se retirent, lorsqu'on les pique. 3. Les entrailles conservent longtemps leur mouvement péristaltique, ou vermiculaire. 4. Une simple injection d'eau chaude ranime le coeur et les muscles, suivant Cowper. 5. Le coeur de la grenouille, surtout exposé au soleil, encore mieux sur une table ou une assiette chaude, se remue pendant une heure et plus, après avoir été arraché du corps. Le mouvement semble-t-il perdu sans ressource? il n'y a qu'à piquer le coeur, et ce muscle creux bat encore. Harvey a fait la même observation sur les crapauds. 6. Bacon de Verulam, dans son Traité Sylva-Sylvarum, parle d'un homme convaincu de trahison, qu'on ouvrit vivant, et dont le coeur jeté dans l'eau chaude sauta à plusieurs reprises, toujours moins haut, à la distance perpendiculaire de 2 pieds. 7. Prenez un petit poulet encore dans l'oeuf; arrachez lui le coeur; vous observerez les mêmes phénomènes, avec à peu près les mêmes circonstances. La seule chaleur de l'haleine ranime un animal prêt à périr dans la machine pneumatique. Les mêmes expériences que nous devons à Boyle et à Sténon, se font dans les pigeons, dans les chiens, dans les lapins, dont les morceaux de coeur se remuent, comme les coeurs entiers. On voit le même mouvement dans les pattes de taupe arrachées. 8. La chenille, les vers, l'araignée, la mouche, l'anguille offrent les mêmes choses à considérer; et le mouvement des parties coupées augmente dans l'eau chaude, à cause du feu qu'elle contient. 9. Un soldat ivre emporta d'un coup de sabre la tête d'un coq d'Inde. Cet animal resta debout, ensuite il marcha, courut; venant à rencontrer une muraille, il se tourna, battit des ailes, en continuant de courir, et tomba enfin. Etendu par terre, tous les muscles de ce coq se remuaient encore. Voilà ce que j'ai vu, et il est facile de voir à peu près ces phénomènes dans les petits chats, ou chiens, dont on a coupé la tête. 10. Les polypes font plus que de se mouvoir, après la section; ils se reproduisent dans huit jours en autant d'animaux qu'il y a de parties coupées. J'en suis fâché pour le système des naturalistes sur la génération, ou plutôt j'en suis bien aise; car que cette découverte nous apprend bien à ne jamais rien conclure de général, même de toutes les expériences connues, et les plus décisives! Voilà beaucoup plus de faits qu'il n'en faut, pour prouver d'une manière incontestable que chaque petite fibre, ou partie des corps organisés, se meut par un principe qui lui est propre, et dont l'action ne dépend point des nerfs, comme les mouvements volontaires, puisque les mouvements en question s'exercent sans que les parties qui les manifestent aient aucun commerce avec la circulation. Or, si cette force se fait remarquer jusques dans des morceaux de fibres, le coeur, qui est un composé de fibres singulièrement entrelacées, doit avoir la même propriété. L'histoire de Bacon n'était pas nécessaire pour me le persuader. Il m'était facile d'en juger, et par la parfaite analogie de la structure du coeur de l'homme et des animaux; et par la masse même du premier, dans laquelle ce mouvement ne se cache aux yeux, que parce qu'il y est étouffé; et enfin parce que tout est froid et affaissé dans les cadavres. Si les dissections se faisaient sur des criminels suppliciés, dont les corps sont encore chauds, on verrait dans leur coeur les mêmes mouvements qu'on observe dans les muscles du visage des gens décapités. Tel est ce principe moteur des corps entiers, ou des parties coupées en morceaux, qu'il produit des mouvements non déréglés, comme on l'a cru, mais très réguliers, et cela, tant dans les animaux chauds et parfaits, que dans ceux qui sont froids et imparfaits. Il ne reste donc aucune ressource à nos adversaires, si ce n'est que de nier mille et mille faits que chacun peut facilement vérifier. Si on me demande à présent quel est le siège de cette force innée dans nos corps, je réponds qu'elle réside très clairement dans ce que les anciens ont appellé parenchyme; c'est à dire dans la substance propre des parties, abstraction faite des veines, des artères, des nerfs, en un mot de l'organisation de tout le corps; et que par conséquent chaque partie contient en soi des ressorts plus ou moins vifs, selon le besoin qu'elles en avaient. Entrons dans quelque détail de ces ressorts de la machine humaine. Tous les mouvements vitaux, animaux, naturels et automatiques se font par leur action. N'est-ce pas machinalement que le corps se retire, frappé de terreur à l'aspect d'un précipice inattendu? que les paupières se baissent à la menace d'un coup, comme on l'a dit? que la pupille s'étrécit au grand jour pour conserver la rétine, et s'élargit pour voir les objets dans l'obscurité? n'est-ce pas machinalement que les pores de la peau se ferment en hiver, pour que le froid ne pénètre pas l'intérieur des vaisseaux? que l'estomac se soulève, irrité par le poison, par une certaine quantité d'opium, par tous les émétiques, etc.? que le coeur, les artères, les muscles se contractent pendant le sommeil, comme pendant la veille? que le poumon fait l'office d'un souflet continuellement exercé? n'est-ce pas machinalement qu'agissent tous les sphincters de la vessie, du rectum, etc.? que le coeur a une contraction plus forte que tout autre muscle? que les muscles érecteurs font dresser la verge dans l'homme, comme dans les animaux qui s'en battent le ventre, et même dans l'enfant, capable d'érection, pour peu que cette partie soit irritée? Ce qui prouve, pour le dire en passant, qu'il est un ressort singulier dans ce membre, encore peu connu, et qui produit des effets qu'on n'a point encore bien expliqués, malgré toutes les lumières de l'anatomie. Je ne m'étendrai pas davantage sur tous ces petits ressorts subalternes connus de tout le monde. Mais il en est un autre plus subtil, et plus merveilleux qui les anime tous; il est la source de tous nos sentiments, de tous nos plaisirs, de toutes nos passions, de toutes nos pensées; car le cerveau a ses muscles pour penser, comme les jambes pour marcher. Je veux parler de ce principe incitant, et impétueux, qu'Hippocrate appelle enormôn (l'âme). Ce principe existe, et il a son siège dans le cerveau à l'origine des nerfs, par lesquels il exerce son empire sur tout le reste du corps. Par là s'explique tout ce qui peut s'expliquer, jusqu'aux effets surprenants des maladies de l'imagination. Mais, pour ne pas languir dans une richesse et une fécondité mal entendue, il faut se borner à un petit nombre de questions et de réflexions. Pourquoi la vue ou la simple idée d'une belle femme nous cause-t-elle des mouvements et des désirs singuliers? Ce qui se passe alors dans certains organes, vient-il de la nature même de ces organes? Point du tout; mais du commerce et de l'espèce de sympathie de ces muscles avec l'imagination. Il n'y a ici qu'un premier ressort excité par le bene placitum des anciens, ou par l'image de la beauté, qui en excite un autre, lequel était fort assoupi, quand l'imagination l'a éveillé: et comment cela, si ce n'est par le désordre et le tumulte du sang et des esprits, qui galopent avec une promptitude extraordinaire, et vont gonfler les corps caverneux? Puisqu'il est des communications évidentes entre la mère et l'enfant [7], et qu'il est dur de nier des faits rapportés par Tulpius et par d'autres écrivains aussi dignes de foi (il n'y en a point qui le soient plus), nous croirons que c'est par la même voie que le foetus ressent l'impétuosité de l'imagination maternelle, comme une cire molle reçoit toutes sortes d'impressions; et que les mêmes traces, ou envies de la mère, peuvent s'imprimer sur le foetus, sans que cela puisse se comprendre, quoiqu'en disent Blondel et tous ses adhérents. Ainsi nous faisons réparation d'honneur au P. Malebranche, beaucoup trop raillé de sa crédulité par les auteurs qui n'ont point observé d'assez près la nature et ont voulu l'assujettir à leur idées. Voyez le portrait de ce fameux Pope, au moins le Voltaire des Anglais. Les efforts, les nerfs de son génie sont peints sur sa physionomie; elle est toute en convulsion; ses yeux sortent de l'orbite, ses sourcils s'élèvent avec les muscles du front. Pourquoi? C'est que l'origine des nerfs est en travail et que tout le corps doit se ressentir d'une espèce d'accouchement aussi laborieux. S'il n'y avait une corde interne qui tirât ainsi celles du dehors, d'où viendraient tous ces phénomènes? Admettre une âme, pour les expliquer, c'est être réduit à l'opération du St. Esprit. En effet, si ce qui pense en mon cerveau n'est pas une partie de ce viscère, et conséquemment de tout le corps, pourquoi, lorsque tranquille dans mon lit je forme le plan d'un ouvrage, ou que je poursuis un raisonnement abstrait, pourquoi mon sang s'échauffe-t-il? pourquoi la fièvre de mon esprit passe-t-elle dans mes veines? Demandez-le aux hommes d'imagination, aux grandes poètes, à ceux qu'un sentiment bien rendu ravit, qu'un goût exquis, que les charmes de la nature, de la vérité ou de la vertu transportent! Par leur enthousiasme, par ce qu'ils vous diront avoir éprouvé, vous jugerez de la cause par les effets: par cette harmonie que Borelli, qu'un seul anatomiste a mieux connue que tous les Leibniziens, vous connaîtrez l'unité matérielle de l'homme. Car enfin si la tension des nerfs qui fait la douleur, cause la fièvre, par laquelle l'esprit est troublé et n'a plus de volonté; et que réciproquement l'esprit trop exercé trouble le corps, et allume ce feu de consomption qui a enlevé Bayle dans un âge si peu avancé; si telle titillation me fait vouloir, me force de désirer ardemment ce dont je ne me souciais nullement le moment d'auparavant; si à leur tour certaines traces du cerveau excitent le même prurit et les mêmes désirs, pourquoi faire double ce qui n'est évidemment qu'un? C'est en vain qu'on se récrie sur l'empire de la volonté. Pour un ordre qu'elle donne, elle subit cent fois le joug. Et quelle merveille que le corps obéisse dan l'état sain, puisqu'un torrent de sang et d'esprits vient l'y forcer, la volonté ayant pour ministres une légion invisible de fluides plus vifs que l'éclair, et toujours prêts a la servir! Mais comme c'est par les nerfs que son pouvoir s'exerce, c'est aussi par eux qu'il est arrêté. La meilleure volonté d'un amant épuisé, les plus violents désirs lui rendront-ils sa vigueur perdue? Hélas! non; et elle en sera la première punie, parceque, posées certaines circonstances, il n'est pas dans sa puissance de ne pas vouloir du plaisir. Ce que j'ai dit de la paralysie, etc. revient ici. La jaunisse vous surprend! ne savez vous pas que la couleur des corps dépend de celle des verres au travers desquels on les regarde! Ignorez-vous que telle est la teinte des humeurs, telle est celle des objets, au moins par rapport à nous, vains jouets de mille illusions? Mais ôtez cette teinte de l'humeur aqueuse de l'oeil; faites couler la bile par son tamis naturel: alors l'âme ayant d'autres yeux, ne verra plus jaune. N'est ce pas encore ainsi qu'en abattant la cataracte, ou en injectant le canal d'Eustachi, on rend la vue aux aveugles, et l'ouie aux sourds? Combien de gens qui n'étaient peut-être que d'habiles charlatans dans des siècles ignorants, ont passé pour faire de grands miracles! La belle âme et la puissante volonté, qui ne peut agir qu'autant que les dispositions du corps le lui permettent, et dont les goûts changent avec l'âge et la fièvre! Faut-il donc s'étonner si les philosophes ont toujours eu en vue la santé du corps pour conserver celle de l'âme, si Pythagore a aussi soigneusement ordonné la diète, que Platon a défendu le vin? Le régime qui convient au corps, est toujours celui par lequel les médecins sensés prétendent qu'on doit préluder, lorsqu'il s'agit de former l'esprit, de l'élever à la connaissance de la vérité et de la vertu; vains sons dans le désordre des maladies et le tumulte des sens! Sans les préceptes de l'hygiène, Epictète, Socrate, Platon, etc. prêchent en vain: toute morale est infructueuse, pour qui n'a pas la sobrieté en partage: c'est la source de toutes les vertus comme l'intempérance est celle de tous les vices. En faut-il davantage (et pourquoi irais-je me perdre dans l'histoire des passions, qui toutes s'expliquent par l'enormôn d'Hippocrate) pour prouver que l'homme n'est qu'un animal, ou un assemblage de ressorts, qui tous se montent les uns par les autres, sans qu'on puisse dire par quel point du cercle humain la nature a commencé? Si ces ressorts diffèrent entr'eux, ce n'est donc que par leur siège et par quelques degrés de force, et jamais par leur nature; et par conséquent l'âme n'est qu'un principe de mouvement, ou une partie matérielle sensible du cerveau, qu'on peut, sans craindre l'erreur, regarder comme un ressort principal de toute la machine, qui a une influence visible sur tous les autres, et même parait avoir été fait le premier; en sorte que tous les autres n'en seraient qu'une émanation, comme on le verra par quelques observations que je rapporterai et qui ont été faites sur divers embryons. Cette oscillation naturelle, ou propre à notre machine, et dont est douée chaque fibre, et, pour ainsi dire, chaque élément fibreux, semblable à celle d'une pendule, ne peut toujours s'exercer. Il faut la renouveler, à mesure qu'elle se perd; lui donner des forces, quand elle languit; l'affaiblir, lorsqu'elle est opprimée par un excès de force et de vigueur. C'est en cela seul que la vraie médecine consiste. Le corps n'est qu'une horloge, dont le nouveau chyle est l'horloger. Le premier soin de la nature, quand il entre dans le sang, c'est d'y exciter une sorte de fièvre, que les chimistes, qui ne rêvent que fourneaux, ont dû prendre pour une fermentation. Cette fièvre procure une plus grande filtration d'esprits, qui machinalement vont animer les muscles et le coeur, comme s'ils y étaient envoyés par ordre de la volonté. Ce sont donc les causes ou les forces de la vie qui entretiennent ainsi durant 100 ans le mouvement perpétuel des solides et des fluides, aussi nécessaire aux uns qu'aux autres. Mais qui peut dire si les solides contribuent à ce jeu, plus que les fluides, et vice versa? Tout ce qu'on sait, c'est que l'action des premiers serait bientôt anéantie, sans le secours des seconds. Ce sont les liqueurs qui par leur choc éveillent et conservent l'élasticité des vaisseaux, de laquelle dépend leur propre circulation. De là vient qu'après la mort le ressort naturel de chaque substance est plus ou moins fort encore suivant les restes de la vie, auxquels il survit, pour expirer le dernier. Tant il est vrai que cette force des parties animales peut bien se conserver et s'augmenter par celle de la circulation, mais qu'elle n'en dépend point, puisqu'elle se passe même de l'intégrité de chaque membre, ou viscère, comme on l'a vu. Je n'ignore pas que cette opinion n'a pas été goûtée de tous les savants, et que Stahl surtout l'a fort dédaignée. Ce grand chimiste a voulu nous persuader que l'âme était la seule cause de tous nos mouvements. Mais c'est parler en fanatique, et non en philosophe. Pour détruire l'hypothèse Stahlienne, il ne faut pas faire tant d'efforts que je vois qu'on en a faits avant moi. Il n'y a qu'à jeter les yeux sur un joueur de violon. Quelle souplesse! Quelle agilité dans les doigts! Les mouvements sont si prompts, qu'il ne paraît presque pas y avoir de succession. Or, je prie, ou plutôt je défie les Stahliens de me dire, eux qui connaissent si bien tout ce que peut notre âme, comment il serait possible qu'elle exécutât si vite tant de mouvements, des mouvements qui se passent si loin d'elle, et en tant d'endroits divers. C'est supposer un joueur de flûte qui pourrait faire de brillantes cadences sur une infinité de trous qu'il ne connaitrait pas, et auxquels il ne pourrait seulement pas appliquer le doigt. Mais disons avec Mr. Hecquet qu'il n'est pas permis à tout le monde d'aller à Corinthe. Et pourquoi Stahl n'aurait-il pas été encore plus favorisé de la nature en qualité d'homme, qu'en qualité de chimiste et de praticien? Il fallait (heureux mortel!) qu'il eût reçu une autre âme que le reste des hommes; une âme souveraine, qui non contente d'avoir quelque empire sur les muscles volontaires, tenait sans peine les rênes de tous les mouvements du corps, pouvait les suspendre, les calmer, ou les exciter à son gré. Avec une maîtresse aussi despotique, dans les mains de laquelle étaient en quelque sorte les battements du coeur et les lois de la circulation, point de fièvre sans doute; point de douleur; point de langueur; ni honteuse impuissance, ni facheux priapisme. L'âme veut, et les ressorts jouent, se dressent, ou se débandent. Comment ceux de la machine de Stahl se sont-ils sitôt détraqués? Qui a chez soi un si grand médecin, devrait être immortel. Stahl, au reste, n'est pas le seul qui ait rejeté le principe d'oscillation des corps organisés. De plus grands esprits ne l'ont pas employé, lorsqu'ils ont voulu expliquer l'action du coeur, l'érection du penis, etc. Il n'y a qu'à lire les Institutions de médecine de Boerhaave, pour voir quels laborieux et séduisants systèmes, faute d'admettre une force aussi frappante dans tous les corps, ce grand homme a été obligé d'enfanter à la sueur de son puissant génie. Willis et Perrault, esprits d'une plus faible trempe, mais observateurs assidus de la nature, que le fameux professeur de Leyde n'a connue que par autrui et n'a eue, pour ainsi dire, que de la seconde main, paraissent avoir mieux aimé supposer une âme généralement répandue par tout le corps, que le principe dont nous parlons. Mais dans cette hypothèse qui fut celle de Virgile et de tous les Epicuriens, hypothèse que l'histoire du polype semblerait favoriser à la première vue, les mouvements qui survivent au sujet dans lequel ils sont inhérents viennent d'un reste d'âme, que conservent encore les parties qui se contractent, sans être désormais irritées par le sang et les esprits. D'où l'on voit que ces écrivains dont les ouvrages solides éclipsent aisément toutes les fables philosophiques, ne se sont trompés que sur le modèle de ceux qui ont donné à la matière la faculté de penser, je veux dire, pour s'être mal exprimés, en termes obscurs, et qui ne signifient rien. En effet, qu'est ce que ce reste d'âme, si ce n'est la force motrice des Leibniziens, mal rendue par une telle expression, et que cependant Perrault surtout a véritablement entrevue. Voy. son Traité de la Mécanique des Animaux. A présent qu'il est clairement démontré contre les Cartésiens, les Stahliens, les Malebranchistes, et les théologiens peu dignes d'être ici placés, que la matière se meut par elle-même, non seulement lorsqu'elle est organisée, comme dans un coeur entier, par exemple, mais lors même que cette organisation est détruite, la curiosité de l'homme voudrait savoir comment un corps, par cela même qu'il est originairement doué d'un souffle de vie, se trouve en conséquence orné de la faculté de sentir, et enfin par celle-ci de la pensée. Et pour en venir à bout, ô bon Dieu, quels efforts n'ont pas faits certains philosophes! et quel galimatias j'ai eu la patience de lire à ce sujet! Tout ce que l'expérience nous apprend, c'est que tant que le mouvement subsiste, si petit qu'il soit dans une ou plusieurs fibres, il n'y a qu'à les piquer, pour réveiller, animer ce mouvement presque éteint, comme on l'a vu dans cette foule d'expériences dont j'ai voulu accabler les systèmes. Il est donc constant que le mouvement et le sentiment s'excitent tour à tour, et dans les corps entiers, et dans les mêmes corps dont la structure est détruite; pour ne rien dire de certaines plantes qui semblent nous offrir les mêmes phénomènes de la réunion du sentiment et du mouvement. Mais de plus, combien d'excellents philosophes ont démontré que la pensée n'est qu'une faculté de sentir, et que l'âme raisonnable n'est que l'âme sensitive appliquée à contempler les idées, et à raisonner! Ce qui serait prouvé par cela seul que lorsque le sentiment est éteint, la pensée l'est aussi, comme dans l'apoplexie, la léthargie, la catalepsie, etc. Car ceux qui ont avancé que l'âme n'avait pas moins pensé dans les maladies soporeuses, quoiqu'elle ne se souvint pas des idées qu'elle avait eues, ont soutenu une chose ridicule. Pour ce qui est de ce développement, c'est une folie de perdre le temps à en rechercher le mécanisme. La nature du mouvement nous est aussi inconnue que celle de la matière. Le moyen de découvrir comment il s'y produit, à moins que de ressusciter avec l'auteur de l'Histoire de l'Ame l'ancienne et inintelligible doctrine des formes substantielles! Je suis donc aussi consolé d'ignorer comment la matière, d'inerte et simple, devient active et composée d'organes, que de ne pouvoir regarder le soleil sans verre rouge: et je suis d'aussi bonne composition sur les autres merveilles incompréhensibles de la nature, sur la production du sentiment et de la pensée dans un être qui ne paraissait autrefois à nos yeux bornés qu'un peu de boue. Qu'on m'accorde seulement que la matière organisée est douée d'un principe moteur, qui seul la différencie de celle qui ne l'est pas (eh! peut-on rien refuser à l'observation la plus incontestable?) et que tout dépend dans les animaux de la diversité de cette organisation, comme je l'ai assez prouvé; c'en est assez pour deviner l'énigme des substances et celle de l'homme. On voit qu'il n'y en a qu'une dans l'univers et que l'homme est la plus parfaite. Il est au singe, aux animaux les plus spirituels, ce que le pendule planétaire de Huygens est à une montre de Julien le Roi. S'il a fallu plus d'instruments, plus de rouages, plus de ressorts pour marquer les mouvements des planètes, que pour marquer les heures, ou les répéter; s'il a fallu plus d'art à Vaucanson pour faire son Fluteur, que pour son Canard, il eût dû en employer encore davantage pour faire un Parleur; machine qui ne peut plus être regardée comme impossible, surtout entre les mains d'un nouveau Prométhée. Il était donc de même nécessaire que la nature employât plus d'art et d'appareil pour faire et entretenir une machine, qui pendant un siècle entier pût marquer tous les battements du coeur et de l'esprit; car si on n'en voit pas au pouls les heures, c'est du moins le baromètre de la chaleur et de la vivacité, par laquelle on peut juger de la nature de l'âme. Je ne me trompe point, le corps humain est une horloge, mais immense, et construite avec tant d'artifice et d'habileté, que si la roue qui sert à marquer les secondes vient à s'arrêter, celle des minutes tourne et va toujours son train, comme la roue des quarts continue de se mouvoir; et ainsi des autres, quand les premières, rouillées, ou dérangées par quelque cause que ce soit, ont interrompu leur marche. Car n'est-ce pas ainsi que l'obstruction de quelques vaisseaux ne suffit pas pour détruire, ou suspendre le fort des mouvements, qui est dans le coeur, comme dans la pièce ouvrière de la machine; puisqu'au contraire les fluides dont le volume est diminué, ayant moins de chemin a faire, le parcourent d'autant plus vite, emportés comme par un nouveau courant, que la force du coeur s'augmente en raison de la résistance qu'il trouve à l'extrémité des vaisseaux? Lorsque le nerf optique seul comprimé ne laisse plus passer l'image des objets, n'est-ce pas ainsi que la privation de la vue n'empêche pas plus l'usage de l'ouïe, que la privation de ce sens, lorsque les fonctions de la portion molle sont interdites, ne suppose celle de l'autre? N'est-ce pas ainsi encore que l'un entend, sans pouvoir dire qu'il entend (si ce n'est après l'attaque du mal) et que l'autre qui n'entend rien, mais dont les nerfs linguaux sont libres dans le cerveau, dit machinalement tous les rêves qui lui passent par la tête? Phénomènes qui ne surprennent point les médecins éclairés. Ils savent à quoi s'en tenir sur la nature de l'homme; et pour le dire en passant: de deux médecins, le meilleur, celui qui mérite le plus de confiance, c'est toujours, à mon avis, celui qui est le plus versé dans la physique, ou la mécanique du corps humain, et qui laissant l'âme et toutes les inquiétudes que cette chimère donne aux sots et aux ignorans, n'est occupé sérieusement que du pur naturalisme. Laissons donc le prétendu Mr. Charp se moquer des philosophes qui ont regardé les animaux, comme des machines. Que je pense différemment! Je crois que Descartes serait un homme respectable à tous égards, si, né dans un siècle qu'il n'eût pas dû éclairer, il eût connu le prix de l'expérience et de l'observation, et le danger de s'en écarter. Mais il n'est pas moins juste que je fasse ici une authentique réparation à ce grand homme, pour tous ces petits philosophes mauvais plaisants, et mauvais singes de Locke, qui, au lieu de rire impudemment au nez de Descartes, feraient mieux de sentir que sans lui le champ de la philosophie, comme celui du bon esprit sans Newton, serait peut être encore en friche. Il est vrai que ce célèbre philosophe s'est beaucoup trompé, et personne n'en disconvient. Mais enfin il a connu la nature animale; il a le premier parfaitement démontré que les animaux étaient de pures machines. Or, après une découverte de cette importance et qui suppose autant de sagacité, le moyen, sans ingratitude, de ne pas faire grâce à toutes ses erreurs! Elles sont à mes yeux toutes réparées par ce grand aveu. Car enfin, quoiqu'il chante sur la distinction des deux substances, il est visible que ce n'est qu'un tour d'adresse, une ruse de style, pour faire avaler aux théologiens un poison caché à l'ombre d'une analogie qui frappe tout le monde, et qu'eux seuls ne voient pas. Car c'est elle, c'est cette forte analogie qui force tous les savants et les vrais juges d'avouer que ces êtres fiers et vains, plus distingués par leur orgueil que par le nom d'hommes, quelque envie qu'ils aient de s'élever, ne sont au fond que des animaux et des machines perpendiculairement rampantes. Elles ont toutes ce merveilleux instinct, dont l'éducation fait de l'esprit, et qui a toujours son siège dans le cerveau, et à son défaut, comme lorsqu'il manque ou est ossifié, dans la moëlle allongée, et jamais dans le cervelet; car je l'ai vu considérablement blessé, d'autres [8] l'ont trouvé squirreux, sans que l'âme cessât de faire ses fonctions. Etre machine, sentir, penser, savoir distinguer le bien du mal, comme le bleu du jaune, en un mot être né avec de l'intelligence et un instinct sûr de morale, et n'être qu'un animal, sont donc des choses qui ne sont pas plus contradictoires qu'être un singe ou un perroquet et savoir se donner du plaisir. Car, puisque l'occasion se présente de le dire, qui eut jamais deviné à priori qu'une goutte de la liqueur qui se lance dans l'accouplement fit ressentir des plaisirs divins, et qu'il en naîtrait une petite créature, qui pourrait un jour, posées certaines lois, jouir des mêmes délices? Je crois la pensée si peu incompatible avec la matière organisée, qu'elle semble en être une propriété, telle que l'électricité, la faculté motrice, l'impénétrabilité, l'étendue, etc. Voulez vous de nouvelles observations? En voici qui sont sans réplique et qui prouvent toutes que l'homme ressemble parfaitement aux animaux dans son origine, comme dans tout ce que nous avons déjà cru essentiel de comparer. J'en appelle à la bonne foi de nos observateurs. Qu'ils nous disent s'il n'est pas vrai que l'homme dans son principe n'est qu'un ver, qui devient homme, comme la chenille papillon. Les plus graves [9] auteurs nous ont appris comment il faut s'y prendre pour voir cet animalcule. Tous les curieux l'ont vu, comme Hartsoeker, dans la semence de l'homme, et non dans celle de la femme; il n'y a que les sots qui s'en soient fait scrupule. Comme chaque goutte de sperme contient une infinité de ces petits vers lorsqu'ils sont lancés à l'ovaire, il n'y a que le plus adroit, ou le plus vigoureux qui ait la force de s'insinuer et de s'implanter dans l'oeuf que fournit la femme, et qui lui donne sa première nourriture. Cet oeuf, quelquefois surpris dans les trompes de Fallope, est porté par ces canaux à la matrice, où il prend racine, comme un grain de blé dans la terre. Mais quoiqu'il y devienne monstrueux par sa croissance de 9 mois, il ne diffère point des oeufs des autres femelles, si ce n'est que sa peau (l'amnios) ne se durcit jamais, et se dilate prodigieusement, comme on en peut juger en comparant les foetus trouvés en situation et près d'éclore (ce que j'ai eu le plaisir d'observer dans une femme morte un moment avant l'accouchement), avec d'autres petits embryons très proches de leur origine: car alors c'est toujours l'oeuf dans sa coque, et l'animal dans l'oeuf, qui, gêné dans ses mouvements, cherche machinalement à voir le jour; et pour y réussir, il commence par rompre avec la tête cette membrane, d'oû il sort, comme le poulet, l'oiseau, etc., de la leur. J'ajouterai une observation que je ne trouve nulle part; c'est que l'amnios n'en est pas plus mince, pour s'être prodigieusement étendu; semblable en cela à la matrice dont la substance même se gonfle de sucs infiltrés, indépendamment de la réplétion et du déploiement de tous ses coudes vasculeux. Voyons l'homme dans et hors de sa coque; examinons avec un microscope les plus jeunes embryons, de 4, de 6, de 8 ou de 15 jours; après ce temps les yeux suffisent. Que voit-on? la tête seule; un petit oeuf rond avec deux points noirs qui marquent les yeux. Avant ce temps, tout étant plus informe, on n'aperçoit qu'une pulpe médullaire, qui est le cerveau, dans lequel se forme d'abord l'origine des nerfs, ou le principe du sentiment, et le coeur qui a déjà par lui-même dans cette pulpe la faculté de battre: c'est le punctum saliens de Malpighi, qui doit peut-être déjà une partie de sa vivacité à l'influence des nerfs. Ensuite peu-à-peu on voit la tête allonger le col, qui en se dilatant forme d'abord le thorax, où le coeur a déjà descendu, pour s'y fixer; après quoi vient le bas ventre qu'une cloison (le diaphragme) sépare. Ces dilatations donnent l'une, les bras, les mains, les doigts, les ongles, et les poils; l'autre les cuisses, les jambes, les pieds, etc., avec la seule différence de situation qu'on leur connait, qui fait l'appui et le balancier du corps. C'est une végétation frappante. Ici, ce sont des cheveux qui couvrent le sommet de nos têtes; là, ce sont des feuilles et des fleurs. Partout brille le même luxe de la nature; et enfin l'esprit recteur des plantes est placé où nous avons notre âme, cette autre quintessence de l'homme. Telle est l'uniformité de la nature qu'on commence à sentir, et l'analogie du règne animal et végétal, de l'homme à la plante. Peut-être même y a-t-il des plantes animal, c'est-à-dire qui en végétant, ou se battent comme les polypes, ou font d'autres fonctions propres aux animaux? Voilà à peu près tout ce qu'on sait de la génération. Que les parties qui s'attirent, qui sont faites pour s'unir ensemble et pour occuper telle ou telle place, se réunissent toutes suivant leur nature; et qu'ainsi se forment les yeux, le coeur, l'estomac et enfin tout le corps, comme de grands hommes l'ont écrit, cela est possible. Mais, comme l'expérience nous abandonne au milieu des ces subtilités, je ne supposerai rien, regardant tout ce qui ne frappe pas mes sens comme un mystère impénétrable. Il est si rare que les deux semences se rencontrent dans le congrès, que je serais tenté de croire que la semence de la femme est inutile à la génération. Mais comment en expliquer les phénomènes, sans ce commode rapport de parties, qui rend si bien raison des ressemblances des enfants, tantôt au père, et tantôt à la mère? D'un autre côté, l'embarras d'une explication doit-elle contrebalancer un fait? Il me parait que c'est le mâle qui fait tout, dans une femme qui dort, comme dans la plus lubrique. L'arrangement des parties serait donc fait de toute éternité dans le germe, ou dans le ver même de l'homme. Mais tout ceci est fort au-dessus de la portée des plus excellents observateurs. Comme ils n'y peuvent rien saisir, ils ne peuvent pas plus juger de la mécanique de la formation et du développement des corps, qu'une taupe du chemin qu'un cerf peut parcourir. Nous sommes de vraies taupes dans le champ de la nature; nous n'y faisons guères que le trajet de cet animal; et c'est notre orgueil qui donne des bornes à ce qui n'en a point. Nous sommes dans le cas d'une montre qui dirait: (un fabuliste en ferait un personnage de conséquence dans un ouvrage frivole) "Quoi! c'est ce sot ouvrier qui m'a faite, moi qui divise le temps! moi qui marque si exactement le cours du soleil; moi qui répète à haute voix les heures que j'indique! non, cela ne se peut pas." Nous dédaignons de même, ingrats que nous sommes, cette mère commune de tous les règnes, comme parlent les chimistes. Nous imaginons ou plutôt supposons une cause supérieure à celle à qui nous devons tout, et qui a véritablement tout fait d'une manière inconcevable. Non, la matière n'a rien de vil, qu'aux yeux grossiers qui la méconnaissent dans ses plus brillants ouvrages; et la nature n'est point une ouvrière bornée. Elle produit des millions d'hommes avec plus de facilité et de plaisir, qu'un horloger n'a de peine à faire la montre la plus composée. Sa puissance éclate également et dans la production du plus vil insecte, et dans celle de l'homme le plus superbe; le règne animal ne lui coûte pas plus que le végétal, ni le plus beau génie qu'un épi de blé. Jugeons donc par ce que nous voyons, de ce qui se dérobe à la curiosité de nos yeux et de nos recherches, et n'imaginons rien au delà. Suivons le singe, le castor, l'éléphant, etc., dans leurs opérations. S'il est évident qu'elles ne peuvent se faire sans intelligence, pourquoi la refuser à ces animaux? et si vous leur accordez une âme, fanatiques, vous êtes perdus; vous aurez beau dire que vous ne décidez point sur sa nature, tandis que vous lui ôtez l'immortalité; qui ne voit que c'est une assertion gratuite? qui ne voit qu'elle doit être ou mortelle, ou immortelle, comme la nôtre, dont elle doit subir le même sort quel qu'il soit! et qu'ainsi c'est tomber dans Scilla pour vouloir éviter Caribde? Brisez la chaîne de vos préjugés; armez-vous du flambeau de l'expérience et vous ferez à la nature l'honneur qu'elle mérite, au lieu de rien conclure à son désavantage, de l'ignorance où elle vous a laissé. Ouvrez les yeux seulement, et laissez-là ce que vous ne pouvez comprendre; et vous verrez que ce laboureur dont l'esprit et les lumières ne s'étendent pas plus loin que les bords de son sillon, ne diffère point essentiellement du plus grand génie, comme l'eût prouvé la dissection des cerveaux de Descartes et de Newton: vous serez persuadé que l'imbécile ou le stupide sont des bêtes à figure humaine, comme le singe plein d'esprit est un petit homme sous une autre forme; et qu'enfin tout dépendant absolument de la diversité de l'organisation, un animal bien construit, à qui on a appris l'astronomie, peut prédire une éclipse, comme la guérison ou la mort, lorsqu'il a porté quelque temps du génie et de bons yeux à l'école d'Hippocrate et au lit des malades. C'est par cette file d'observations et de vérités qu'on parvient à lier à la matière l'admirable propriété de penser, sans qu'on en puisse voir les liens, parce que le sujet de cet attribut nous est essentiellement inconnu. Ne disons point que toute machine, ou tout animal, périt tout-à-fait, ou prend une autre forme, après la mort; car nous n'en savons absolument rien. Mais assurer qu'une machine immortelle est une chimère, ou un être de raison, c'est faire un raisonnement aussi absurde que celui que feraient des chenilles, qui, voyant les dépouilles de leurs semblables, déploreraient amèrement le sort de leur espèce qui leur semblerait s'anéantir. L'âme de ces insectes (car chaque animal a la sienne) est trop bornée pour comprendre les métamorphoses de la nature. Jamais un seul des plus rusés d'entr'eux n'eût imaginé qu'il dût devenir papillon. Il en est de même de nous. Que savons-nous plus de notre destinée, que de notre origine? Soumettons-nous donc à une ignorance invincible de laquelle notre bonheur dépend. Qui pensera ainsi, sera sage, juste, tranquille sur son sort, et par conséquent heureux. Il attendra la mort, sans la craindre, ni la désirer; et chérissant la vie, comprenant à peine comment le dégoût vient corrompre un coeur dans ce lieu plein de délices; plein de respect pour la nature, plein de reconnaissance, d'attachement et de tendresse, à proportion du sentiment et des bienfaits qu'il en a reçus, heureux enfin de la sentir, et d'être au charmant spectacle de l'univers, il ne le détruira certainement jamais dans soi, ni dans les autres. Que dis-je! plein d'humanité, il en aimera le caractère jusques dans ses ennemis. Jugez comme il traitera les autres! Il plaindra les vicieux, sans les haïr; ce ne seront à ses yeux que des hommes contrefaits. Mais en faisant grâce aux défauts de la conformation de l'esprit et du corps, il n'en admirera pas moins leurs beautés et leurs vertus. Ceux que la nature aura favorisés lui paraîtront mériter plus d'égards que ceux qu'elle aura traités en marâtre. C'est ainsi qu'on a vu que les dons naturels, la source de tout ce qui s'acquiert, trouvent dans la bouche et le coeur du matérialiste des hommages que tout autre leur refuse injustement. Enfin le matérialiste convaincu, quoi que murmure sa propre vanité, qu'il n'est qu'une machine, ou un animal, ne maltraitera point ses semblables; trop instruit sur la nature de ces actions, dont l'inhumanité est toujours proportionnée au degré d'analogie prouvée ci devant; et ne voulant pas en un mot, suivant la loi naturelle donnée à tous les animaux, faire à autrui ce qu'il ne voudrait pas qu'il lui fît. Concluons donc hardiment que l'homme est une machine; et qu'il n'y a dans tout l'univers qu'une seule substance diversement modifiée. Ce n'est point ici une hypothèse élevée à force de demandes et de suppositions: ce n'est point l'ouvrage du préjugé, ni même de ma raison seule; j'eusse dédaigné un guide que je crois si peu sûr, si mes sens portant, pour ainsi dire, le flambeau, ne m'eûssent engagé à la suivre, en l'éclairant. L'expérience m'a donc parlé pour la raison; c'est ainsi que je les ai jointes ensemble. Mais on a dû voir que je ne me suis permis le raisonnement le plus rigoureux et le plus immédiatement tiré, qu'à la suite d'une multitude d'observations physiques qu'aucun savant ne contestera; et c'est encore eux seuls que je reconnais pour juges des conséquences que j'en tire; récusant ici tout homme à préjugés, et qui n'est ni anatomiste, ni au fait de la seule philosophie qui soit ici de mise, celle du corps humain. Que pourraient contre un chêne aussi ferme et solide ces faibles roseaux de la théologie, de la métaphysique et des écoles; armes puériles, semblables aux fleurets de nos salles, qui peuvent bien donner le plaisir de l'escrime, mais jamais entamer son adversaire. Faut-il dire que je parle de ces idées creuses et triviales, de ces raisonnements rebattus et pitoyables, qu'on fera sur la prétendue incompatibilité de deux substances qui se touchent et se remuent sans cesse l'une et l'autre, tant qu'il restera l'ombre du préjugé ou de la superstition sur la terre? Voilà mon système, ou plutôt la vérité, si je ne me trompe fort. Elle est courte et simple. Dispute à présent qui voudra! MAN A MACHINE. It is not enough for a wise man to study nature and truth; he should dare state truth for the benefit of the few who are willing and able to think. As for the rest, who are voluntarily slaves of prejudice, they can no more attain truth, than frogs can fly. I reduce to two the systems of philosophy which deal with man's soul. The first and older system is materialism; the second is spiritualism. The metaphysicians who have hinted that matter may well be endowed with the faculty of thought{1} have perhaps not reasoned ill. For there is in this case a certain advantage in their inadequate way of expressing their meaning. In truth, to ask whether matter can think, without considering it otherwise than in itself, is like asking whether matter can tell time. It may be foreseen that we shall avoid this reef upon which Locke had the bad luck to make shipwreck. The Leibnizians with their monads have set up an unintelligible hypothesis. They have rather spiritualized matter than materialized the soul. How can we define a being whose nature is absolutely unknown to us?{2} Descartes and all the Cartesians, among whom the followers of Malebranche have long been numbered, have made the same mistake. They have taken for granted two distinct substances in man, as if they had seen them, and positively counted them. The wisest men have declared that the soul can not know itself save by the light of faith. However, as reasonable beings they have thought that they could reserve for themselves the right of examining what the Bible means by the word "spirit," which it uses in speaking of the human soul. And if in their investigation, they do not agree with the theologians on this point, are the theologians more in agreement among themselves on all other points? Here is the result in a few words, of all their reflections. If there is a God, He is the Author of nature as well as of revelation. He has given us the one to explain the other, and reason to make them agree. To distrust the knowledge that can be drawn from the study of animated bodies, is to regard nature and revelation as two contraries which destroy each the other, and consequently to dare uphold the absurd doctrine, that God contradicts Himself in His various works and deceives us. If there is a revelation, it can not then contradict nature. By nature only can we understand the meaning of the words of the Gospel, of which experience is the only true interpreter. In fact, the commentators before our time have only obscured the truth. We can judge of this by the author of the "Spectacle of Nature."{3} "It is astonishing," he says concerning Locke, "that a man who degrades our soul far enough to consider it a soul of clay should dare set up reason as judge and sovereign arbiter of the mysteries of faith, for," he adds, "what an astonishing idea of Christianity one would have, if one were to follow reason." Not only do these reflections fail to elucidate faith, but they also constitute such frivolous objections to the method of those who undertake to interpret the Scripture, that I am almost ashamed to waste time in refuting them. The excellence of reason does not depend on a big word devoid of meaning (immateriality), but on the force, extent, and perspicuity of reason itself. Thus a "soul of clay" which should discover, at one glance, as it were, the relations and the consequences of an infinite number of ideas hard to understand, would evidently be preferable to a foolish and stupid soul, though that were composed of the most precious elements. A man is not a philosopher because, with Pliny, he blushes over the wretchedness of our origin. What seems vile is here the most precious of things, and seems to be the object of nature's highest art and most elaborate care. But as man, even though he should come from an apparently still more lowly source, would yet be the most perfect of all beings, so whatever the origin of his soul, if it is pure, noble, and lofty, it is a beautiful soul which dignifies the man endowed with it. Pluche's second way of reasoning seems vicious to me, even in his system, which smacks a little of fanaticism; for [on his view] if we have an idea of faith as being contrary to the clearest principles, to the most incontestable truths, we must yet conclude, out of respect for revelation and its author, that this conception is false, and that we do not yet understand the meaning of the words of the Gospel. Of the two alternatives, only one is possible: either everything is illusion, nature as well as revelation, or experience alone can explain faith. But what can be more ridiculous than the position of our author! Can one imagine hearing a Peripatetic say, "We ought not to accept the experiments of Torricelli,{4} for if we should accept them, if we should rid ourselves of the horror of the void, what an astonishing philosophy we should have!" I have shown how vicious the reasoning of Pluche is [10] in order to prove, in the first place, that if there is a revelation, it is not sufficiently demonstrated by the mere authority of the Church, and without any appeal to reason, as all those who fear reason claim: and in the second place, to protect against all assault the method of those who would wish to follow the path that I open to them, of interpreting supernatural things, incomprehensible in themselves, in the light of those ideas with which nature has endowed us. Experience and observation should therefore be our only guides here. Both are to be found throughout the records of the physicians who were philosophers, and not in the works of the philosophers who were not physicians. The former have traveled through and illuminated the labyrinth of man; they alone have laid bare to us those springs [of life] hidden under the external integument which conceals so many wonders from our eyes. They alone, tranquilly contemplating our soul, have surprised it, a thousand times, both in its wretchedness and in its glory, and they have no more despised it in the first estate, than they have admired it in the second. Thus, to repeat, only the physicians have a right to speak on this subject.{5} What could the others, especially the theologians, have to say? Is it not ridiculous to hear them shamelessly coming to conclusions about a subject concerning which they have had no means of knowing anything, and from which on the contrary they have been completely turned aside by obscure studies that have led them to a thousand prejudiced opinions,--in a word, to fanaticism, which adds yet more to their ignorance of the mechanism of the body? But even though we have chosen the best guides, we shall still find many thorns and stumbling blocks in the way. Man is so complicated a machine{6} that it is impossible to get a clear idea of the machine beforehand, and hence impossible to define it. For this reason, all the investigations have been vain, which the greatest philosophers have made à priori, that is to say, in so far as they use, as it were, the wings of the spirit. Thus it is only à posteriori or by trying to disentangle the soul from the organs of the body, so to speak, that one can reach the highest probability concerning man's own nature, even though one can not discover with certainty what his nature is. Let us then take in our hands the staff of experience,{7} paying no heed to the accounts of all the idle theories of philosophers. To be blind and to think that one can do without this staff is the worst kind of blindness. How truly a contemporary writer says that only vanity fails to gather from secondary causes the same lessons as from primary causes! One can and one even ought to admire all these fine geniuses in their most useless works, such men as Descartes, Malebranche, Leibniz, Wolff and the rest, but what profit, I ask, has any one gained from their profound meditations, and from all their works? Let us start out then to discover not what has been thought, but what must be thought for the sake of repose in life. There are as many different minds, different characters, and different customs, as there are different temperaments. Even Galen{8} knew this truth which Descartes carried so far as to claim that medicine alone can change minds and morals, along with bodies. (By the writer of "L'histoire de l'âme,"{9} this teaching is incorrectly attributed to Hippocrates.{10}) It is true that melancholy, bile, phlegm, blood etc.--according to the nature, the abundance, and the different combination of these humors--make each man different from another.{11} In disease the soul is sometimes hidden, showing no sign of life; sometimes it is so inflamed by fury that it seems to be doubled; sometimes, imbecility vanishes and the convalescence of an idiot produces a wise man. Sometimes, again, the greatest genius becomes imbecile and loses the sense of self. Adieu then to all that fine knowledge, acquired at so high a price, and with so much trouble! Here is a paralytic who asks if his leg is in bed with him; there is a soldier who thinks that he still has the arm which has been cut off. The memory of his old sensations, and of the place to which they were referred by his soul, is the cause of his illusion, and of this kind of delirium. The mere mention of the member which he has lost is enough to recall it to his mind, and to make him feel all its motions; and this causes him an indefinable and inexpressible kind of imaginary suffering. This man cries like a child at death's approach, while this other jests. What was needed to change the bravery of Caius Julius, Seneca, or Petronius into cowardice or faintheartedness? Merely an obstruction in the spleen, in the liver, an impediment in the portal vein? Why? Because the imagination is obstructed along with the viscera, and this gives rise to all the singular phenomena of hysteria and hypochondria. What can I add to the stories already told of those who imagine themselves transformed into wolf-men, cocks or vampires, or of those who think that the dead feed upon them? Why should I stop to speak of the man who imagines that his nose or some other member is of glass? The way to help this man regain his faculties and his own flesh-and-blood nose is to advise him to sleep on hay, lest he break the fragile organ, and then to set fire to the hay that he may be afraid of being burned--a fear which has sometimes cured paralysis. But I must touch lightly on facts which everybody knows. Neither shall I dwell long on the details of the effects of sleep. Here a tired soldier snores in a trench, in the middle of the thunder of hundreds of cannon. His soul hears nothing; his sleep is as deep as apoplexy. A bomb is on the point of crushing him. He will feel this less perhaps than he feels an insect which is under his foot. On the other hand, this man who is devoured by jealousy, hatred, avarice, or ambition, can never find any rest. The most peaceful spot, the freshest and most calming drinks are alike useless to one who has not freed his heart from the torment of passion. The soul and the body fall asleep together. As the motion of the blood is calmed, a sweet feeling of peace and quiet spreads through the whole mechanism. The soul feels itself little by little growing heavy as the eyelids droop, and loses its tenseness, as the fibres of the brain relax; thus little by little it becomes as if paralyzed and with it all the muscles of the body. These can no longer sustain the weight of the head, and the soul can no longer bear the burden of thought; it is in sleep as if it were not. Is the circulation too quick? the soul can not sleep. Is the soul too much excited? the blood can not be quieted: it gallops through the veins with an audible murmur. Such are the two opposite causes of insomnia. A single fright in the midst of our dreams makes the heart beat at double speed and snatches us from needed and delicious repose, as a real grief or an urgent need would do. Lastly as the mere cessation of the functions of the soul produces sleep, there are, even when we are awake (or at least when we are half awake), kinds of very frequent short naps of the mind, vergers' dreams, which show that the soul does not always wait for the body to sleep. For if the soul is not fast asleep, it surely is not far from sleep, since it can not point out a single object to which it has attended, among the uncounted number of confused ideas which, so to speak, fill the atmosphere of our brains like clouds. Opium is too closely related to the sleep it produces, to be left out of consideration here. This drug intoxicates, like wine, coffee, etc., each in its own measure and according to the dose.{12} It makes a man happy in a state which would seemingly be the tomb of feeling, as it is the image of death. How sweet is this lethargy! The soul would long never to emerge from it. For the soul has been a prey to the most intense sorrow, but now feels only the joy of suffering past, and of sweetest peace. Opium even alters the will, forcing the soul which wished to wake and to enjoy life, to sleep in spite of itself. I shall omit any reference to the effect of poisons. Coffee, the well-known antidote for wine, by scourging the imagination, cures our headaches and scatters our cares without laying up for us, as wine does, other headaches for the morrow. But let us contemplate the soul in its other needs. The human body is a machine which winds its own springs. It is the living image of perpetual movement. Nourishment keeps up the movements which fever excites. Without food, the soul pines away, goes mad, and dies exhausted. The soul is a taper whose light flares up the moment before it goes out. But nourish the body, pour into its veins life-giving juices and strong liquors, and then the soul grows strong like them, as if arming itself with a proud courage, and the soldier whom water would have made flee, grows bold and runs joyously to death to the sound of drums. Thus a hot drink sets into stormy movement the blood which a cold drink would have calmed. What power there is in a meal! Joy revives in a sad heart, and infects the souls of comrades, who express their delight in the friendly songs in which the Frenchman excels. The melancholy man alone is dejected, and the studious man is equally out of place [in such company]. Raw meat makes animals fierce, and it would have the same effect on man. This is so true that the English who eat meat red and bloody, and not as well done as ours, seem to share more or less in the savagery due to this kind of food, and to other causes which can be rendered ineffective by education only. This savagery creates in the soul, pride, hatred, scorn of other nations, indocility and other sentiments which degrade the character, just as heavy food makes a dull and heavy mind whose usual traits are laziness and indolence. Pope understood well the full power of greediness when he said:{13} "Catius is ever moral, ever grave, Thinks who endures a knave is next a knave, Save just at dinner--then prefers no doubt, A rogue with ven'son to a saint without." Elsewhere he says: "See the same man in vigor, in the gout Alone, in company, in place or out, Early at business and at hazard late, Mad at a fox chase, wise at a debate, Drunk at a borough, civil at a ball, Friendly at Hackney, faithless at White Hall." In Switzerland we had a bailiff by the name of M. Steigner de Wittighofen. When he fasted he was a most upright and even a most indulgent judge, but woe to the unfortunate man whom he found on the culprit's bench after he had had a large dinner! He was capable of sending the innocent like the guilty to the gallows. We think we are, and in fact we are, good men, only as we are gay or brave; everything depends on the way our machine is running. One is sometimes inclined to say that the soul is situated in the stomach, and that Van Helmont,{14} who said that the seat of the soul was in the pylorus, made only the mistake of taking the part for the whole. To what excesses cruel hunger can bring us! We no longer regard even our own parents and children. We tear them to pieces eagerly and make horrible banquets of them; and in the fury with which we are carried away, the weakest is always the prey of the strongest.... One needs only eyes to see the necessary influence of old age on reason. The soul follows the progress of the body, as it does the progress of education. In the weaker sex, the soul accords also with delicacy of temperament, and from this delicacy follow tenderness, affection, quick feelings due more to passion than to reason, prejudices, and superstitions, whose strong impress can hardly be effaced. Man, on the other hand, whose brain and nerves partake of the firmness of all solids, has not only stronger features but also a more vigorous mind. Education, which women lack, strengthens his mind still more. Thus with such help of nature and art, why should not a man be more grateful, more generous, more constant in friendship, stronger in adversity? But, to follow almost exactly the thought of the author of the "Lettres sur la Physiognomie,"{15} the sex which unites the charms of the mind and of the body with almost all the tenderest and most delicate feelings of the heart, should not envy us the two capacities which seem to have been given to man, the one merely to enable him better to fathom the allurements of beauty, and the other merely to enable him to minister better to its pleasures. It is no more necessary to be just as great a physiognomist as this author, in order to guess the quality of the mind from the countenance or the shape of the features, provided these are sufficiently marked, than it is necessary to be a great doctor to recognize a disease accompanied by all its marked symptoms. Look at the portraits of Locke, of Steele, of Boerhaave,{16} of Maupertuis,{17} and the rest, and you will not be surprised to find strong faces and eagle eyes. Look over a multitude of others, and you can always distinguish the man of talent from the man of genius, and often even an honest man from a scoundrel. For example, it has been noticed that a celebrated poet combines (in his portrait) the look of a pickpocket with the fire of Prometheus. History provides us with a noteworthy example of the power of temperature. The famous Duke of Guise was so strongly convinced that Henry the Third, in whose power he had so often been, would never dare assassinate him, that he went to Blois. When the Chancelor Chiverny learned of the duke's departure, he cried, "He is lost." After this fatal prediction had been fulfilled by the event, Chiverny was asked why he made it. "I have known the king for twenty years," said he; "he is naturally kind and even weakly indulgent, but I have noticed that when it is cold, it takes nothing at all to provoke him and send him into a passion." One nation is of heavy and stupid wit, and another quick, light and penetrating. Whence comes this difference, if not in part from the difference in foods, and difference in inheritance, [11] and in part from the mixture of the diverse elements which float around in the immensity of the void? The mind, like the body, has its contagious diseases and its scurvy. Such is the influence of climate, that a man who goes from one climate to another, feels the change, in spite of himself. He is a walking plant which has transplanted itself; if the climate is not the same, it will surely either degenerate or improve. Furthermore, we catch everything from those with whom we come in contact; their gestures, their accent, etc.; just as the eyelid is instinctively lowered when a blow is foreseen, or as (for the same reason) the body of the spectator mechanically imitates, in spite of himself, all the motions of a good mimic.{18} From what I have just said, it follows that a brilliant man is his own best company, unless he can find other company of the same sort. In the society of the unintelligent, the mind grows rusty for lack of exercise, as at tennis a ball that is served badly is badly returned. I should prefer an intelligent man without an education, if he were still young enough, to a man badly educated. A badly trained mind is like an actor whom the provinces have spoiled. Thus, the diverse states of the soul are always correlative with those of the body.{19} But the better to show this dependence, in its completeness and its causes, let us here make use of comparative anatomy; let us lay bare the organs of man and of animals. How can human nature be known, if we may not derive any light from an exact comparison of the structure of man and of animals? In general, the form and the structure of the brains of quadrupeds are almost the same as those of the brain of man; the same shape, the same arrangement everywhere, with this essential difference, that of all the animals man is the one whose brain is largest, and, in proportion to its mass, more convoluted than the brain of any other animal; then come the monkey, the beaver, the elephant, the dog, the fox, the cat. These animals are most like man, for among them, too, one notes the same progressive analogy in relation to the corpus callosum in which Lancisi--anticipating the late M. de la Peyronie{20}--established the seat of the soul. The latter, however, illustrated the theory by innumerable experiments. Next after all the quadrupeds, birds have the largest brains. Fish have large heads, but these are void of sense, like the heads of many men. Fish have no corpus callosum, and very little brain, while insects entirely lack brain. I shall not launch out into any more detail about the varieties of nature, nor into conjectures concerning them, for there is an infinite number of both, as any one can see by reading no further than the treatises of Willis "De Cerebro" and "De Anima Brutorum."{21} I shall draw the conclusions which follow clearly from these incontestable observations: 1st, that the fiercer animals are, the less brain they have; 2d, that this organ seems to increase in size in proportion to the gentleness of the animal; 3d, that nature seems here eternally to impose a singular condition, that the more one gains in intelligence the more one loses in instinct. Does this bring gain or loss? Do not think, however, that I wish to infer by that, that the size alone of the brain, is enough to indicate the degree of tameness in animals: the quality must correspond to the quantity, and the solids and liquids must be in that due equilibrium which constitutes health. If, as is ordinarily observed, the imbecile does not lack brain, his brain will be deficient in its consistency--for instance, in being too soft. The same thing is true of the insane, and the defects of their brains do not always escape our investigation. But if the causes of imbecility, insanity, etc., are not obvious, where shall we look for the causes of the diversity of all minds? They would escape the eyes of a lynx and of an argus. A mere nothing, a tiny fibre, something that could never be found by the most delicate anatomy, would have made of Erasmus and Fontenelle{22} two idiots, and Fontenelle himself speaks of this very fact in one of his best dialogues. Willis has noticed in addition to the softness of the brain-substance in children, puppies, and birds, that the corpora striata are obliterated and discolored in all these animals, and that the striations are as imperfectly formed as in paralytics.... However cautious and reserved one may be about the consequences that can be deduced from these observations, and from many others concerning the kind of variation in the organs, nerves, etc., [one must admit that] so many different varieties can not be the gratuitous play of nature. They prove at least the necessity for a good and vigorous physical organization, since throughout the animal kingdom the soul gains force with the body and acquires keenness, as the body gains strength. Let us pause to contemplate the varying capacity of animals to learn. Doubtless the analogy best framed leads the mind to think that the causes we have mentioned produce all the difference that is found between animals and men, although we must confess that our weak understanding, limited to the coarsest observations, can not see the bonds that exist between cause and effects. This is a kind of harmony that philosophers will never know. Among animals, some learn to speak and sing; they remember tunes, and strike the notes as exactly as a musician. Others, for instance the ape, show more intelligence, and yet can not learn music. What is the reason for this, except some defect in the organs of speech? But is this defect so essential to the structure that it could never be remedied? In a word, would it be absolutely impossible to teach the ape a language?{23} I do not think so. I should choose a large ape in preference to any other, until by some good fortune another kind should be discovered, more like us, for nothing prevents there being such an one in regions unknown to us. The ape resembles us so strongly that naturalists have called it "wild man" or "man of the woods." I should take it in the condition of the pupils of Amman,{24} that is to say, I should not want it to be too young or too old; for apes that are brought to Europe are usually too old. I would choose the one with the most intelligent face, and the one which, in a thousand little ways, best lived up to its look of intelligence. Finally not considering myself worthy to be his master, I should put him in the school of that excellent teacher whom I have just named, or with another teacher equally skilful, if there is one. You know by Amman's work, and by all those [12] who have interpreted his method, all the wonders he has been able to accomplish for those born deaf. In their eyes he discovered ears, as he himself explains, and in how short a time! In short he taught them to hear, speak, read, and write. I grant that a deaf person's eyes see more clearly and are keener than if he were not deaf, for the loss of one member or sense can increase the strength or acuteness of another, but apes see and hear, they understand what they hear and see, and grasp so perfectly the signs that are made to them, that I doubt not that they would surpass the pupils of Amman in any other game or exercise. Why then should the education of monkeys be impossible? Why might not the monkey, by dint of great pains, at last imitate after the manner of deaf mutes, the motions necessary for pronunciation? I do not dare decide whether the monkey's organs of speech, however trained, would be incapable of articulation. But, because of the great analogy between ape and man{25} and because there is no known animal whose external and internal organs so strikingly resemble man's, it would surprise me if speech were absolutely impossible to the ape. Locke, who was certainly never suspected of credulity, found no difficulty in believing the story told by Sir William Temple{26} in his memoirs, about a parrot which could answer rationally, and which had learned to carry on a kind of connected conversation, as we do. I know that people have ridiculed [13] this great metaphysician; but suppose some one should have announced that reproduction sometimes takes place without eggs or a female, would he have found many partisans? Yet M. Trembley{27} has found cases where reproduction takes place without copulation and by fission. Would not Amman too have passed for mad if he had boasted that he could instruct scholars like his in so short a time, before he had happily accomplished the feat? His successes have, however, astonished the world; and he, like the author of "The History of Polyps," has risen to immortality at one bound. Whoever owes the miracles that he works to his own genius surpasses, in my opinion, the man who owes his to chance. He who has discovered the art of adorning the most beautiful of the kingdoms [of nature], and of giving it perfections that it did not have, should be rated above an idle creator of frivolous systems, or a painstaking author of sterile discoveries. Amman's discoveries are certainly of a much greater value; he has freed men from the instinct to which they seemed to be condemned, and has given them ideas, intelligence, or in a word, a soul which they would never have had. What greater power than this! Let us not limit the resources of nature; they are infinite, especially when reinforced by great art. Could not the device which opens the Eustachian canal of the deaf, open that of apes? Might not a happy desire to imitate the master's pronunciation, liberate the organs of speech in animals that imitate so many other signs with such skill and intelligence? Not only do I defy any one to name any really conclusive experiment which proves my view impossible and absurd; but such is the likeness of the structure and functions of the ape to ours that I have very little doubt that if this animal were properly trained he might at last be taught to pronounce, and consequently to know, a language. Then he would no longer be a wild man, nor a defective man, but he would be a perfect man, a little gentleman, with as much matter or muscle as we have, for thinking and profiting by his education. The transition from animals to man is not violent, as true philosophers will admit. What was man before the invention of words and the knowledge of language?{28} An animal of his own species with much less instinct than the others. In those days, he did not consider himself king over the other animals, nor was he distinguished from the ape, and from the rest, except as the ape itself differs from the other animals, i. e., by a more intelligent face. Reduced to the bare intuitive knowledge of the Leibnizians he saw only shapes and colors, without being able to distinguish between them: the same, old as young, child at all ages, he lisped out his sensations and his needs, as a dog that is hungry or tired of sleeping, asks for something to eat, or for a walk. Words, languages, laws, sciences, and the fine arts have come, and by them finally the rough diamond of our mind has been polished. Man has been trained in the same way as animals. He has become an author, as they became beasts of burden. A geometrician has learned to perform the most difficult demonstrations and calculations, as a monkey has learned to take his little hat off and on, and to mount his tame dog. All has been accomplished through signs, every species has learned what it could understand, and in this way men have acquired symbolic knowledge, still so called by our German philosophers. Nothing, as any one can see, is so simple as the mechanism of our education. Everything may be reduced to sounds or words that pass from the mouth of one through the ears of another into his brain. At the same moment, he perceives through his eyes the shape of the bodies of which these words are the arbitrary signs. But who was the first to speak? Who was the first teacher of the human race? Who invented the means of utilizing the plasticity of our organism? I can not answer: the names of these first splendid geniuses have been lost in the night of time. But art is the child of nature, so nature must have long preceded it. We must think that the men who were the most highly organized, those on whom nature had lavished her richest gifts, taught the others. They could not have heard a new sound for instance, nor experienced new sensations, nor been struck by all the varied and beautiful objects that compose the ravishing spectacle of nature without finding themselves in the state of mind of the deaf man of Chartres, whose experience was first related by the great Fontenelle,{29} when, at forty years, he heard for the first time, the astonishing sound of bells. Would it be absurd to conclude from this that the first mortals tried after the manner of this deaf man, or like animals and like mutes (another kind of animals), to express their new feelings by motions depending on the nature of their imagination, and therefore afterwards by spontaneous sounds, distinctive of each animal, as the natural expression of their surprise, their joy, their ecstasies and their needs? For doubtless those whom nature endowed with finer feeling had also greater facility in expression. That is the way in which, I think, men have used their feeling and their instinct to gain intelligence and then have employed their intelligence to gain knowledge. Those are the ways, so far as I can understand them, in which men have filled the brain with the ideas, for the reception of which nature made it. Nature and man have helped each other; and the smallest beginnings have, little by little, increased, until everything in the universe could be as easily described as a circle. As a violin string or a harpsichord key vibrates and gives forth sound, so the cerebral fibres, struck by waves of sound, are stimulated to render or repeat the words that strike them. And as the structure of the brain is such that when eyes well formed for seeing, have once perceived the image of objects, the brain can not help seeing their images and their differences, so when the signs of these differences have been traced or imprinted in the brain, the soul necessarily examines their relations--an examination that would have been impossible without the discovery of signs or the invention of language. At the time when the universe was almost dumb, the soul's attitude toward all objects was that of a man without any idea of proportion toward a picture or a piece of sculpture, in which he could distinguish nothing; or the soul was like a little child (for the soul was then in its infancy) who, holding in his hand small bits of straw or wood, sees them in a vague and superficial way without being able to count or distinguish them. But let some one attach a kind of banner, or standard, to this bit of wood (which perhaps is called a mast), and another banner to another similar object; let the first be known by the symbol 1, and the second by the symbol or number 2, then the child will be able to count the objects, and in this way he will learn all of arithmetic. As soon as one figure seems equal to another in its numerical sign, he will decide without difficulty that they are two different bodies, that 1 + 1 make 2, and 2 + 2 make 4, [14] etc. This real or apparent likeness of figures is the fundamental basis of all truths and of all we know. Among these sciences, evidently those whose signs are less simple and less sensible are harder to understand than the others, because more talent is required to comprehend and combine the immense number of words by which such sciences express the truths in their province. On the other hand, the sciences that are expressed by numbers or by other small signs, are easily learned; and without doubt this facility rather than its demonstrability is what has made the fortune of algebra. All this knowledge, with which vanity fills the balloon-like brains of our proud pedants, is therefore but a huge mass of words and figures, which form in the brain all the marks by which we distinguish and recall objects. All our ideas are awakened after the fashion in which the gardener who knows plants recalls all stages of their growth at sight of them. These words and the objects designated by them are so connected in the brain that it is comparatively rare to imagine a thing without the name or sign that is attached to it. I always use the word "imagine," because I think that everything is the work of imagination, and that all the faculties of the soul can be correctly reduced to pure imagination in which they all consist.{30} Thus judgment, reason, and memory are not absolute parts of the soul, but merely modifications of this kind of medullary screen upon which images of the objects painted in the eye are projected as by a magic lantern. But if such is the marvelous and incomprehensible result of the structure of the brain, if everything is perceived and explained by imagination, why should we divide the sensitive principle which thinks in man? Is not this a clear inconsistency in the partisans of the simplicity of the mind? For a thing that is divided can no longer without absurdity be regarded as indivisible. See to what one is brought by the abuse of language and by those fine words (spirituality, immateriality, etc.) used haphazard and not understood even by the most brilliant.{31} Nothing is easier than to prove a system based, as this one is, on the intimate feeling and personal experience of each individual. If the imagination, or, let us say, that fantastic part of the brain whose nature is as unknown to us as its way of acting, be naturally small or weak, it will hardly be able to compare the analogy or the resemblance of its ideas, it will be able to see only what is face to face with it, or what affects it very strongly; and how will it see all this! Yet it is always imagination which apperceives, and imagination which represents to itself all objects along with their names and symbols; and thus, once again, imagination is the soul, since it plays all the rôles of the soul. By the imagination, by its flattering brush, the cold skeleton of reason takes on living and ruddy flesh, by the imagination the sciences flourish, the arts are adorned, the wood speaks, the echoes sigh, the rocks weep, marble breathes, and all inanimate objects gain life. It is imagination again which adds the piquant charm of voluptuousness to the tenderness of an amorous heart; which makes tenderness bud in the study of the philosopher and of the dusty pedant, which, in a word, creates scholars as well as orators and poets. Foolishly decried by some, vainly praised by others, and misunderstood by all; it follows not only in the train of the graces and of the fine arts, it not only describes, but can also measure nature. It reasons, judges, analyzes, compares, and investigates. Could it feel so keenly the beauties of the pictures drawn for it, unless it discovered their relations? No, just as it can not turn its thoughts on the pleasures of the senses, without enjoying their perfection or their voluptuousness, it can not reflect on what it has mechanically conceived, without thus being judgment itself. The more the imagination or the poorest talent is exercised, the more it gains in embonpoint, so to speak, and the larger it grows. It becomes sensitive, robust, broad, and capable of thinking. The best of organisms has need of this exercise. Man's preeminent advantage is his organism.{32} In vain all writers of books on morals fail to regard as praiseworthy those qualities that come by nature, esteeming only the talents gained by dint of reflection and industry. For whence come, I ask, skill, learning, and virtue, if not from a disposition that makes us fit to become skilful, wise and virtuous? And whence again, comes this disposition, if not from nature? Only through nature do we have any good qualities; to her we owe all that we are. Why then should I not esteem men with good natural qualities as much as men who shine by acquired and as it were borrowed virtues? Whatever the virtue may be, from whatever source it may come, it is worthy of esteem; the only question is, how to estimate it. Mind, beauty, wealth, nobility, although the children of chance, all have their own value, as skill, learning and virtue have theirs. Those upon whom nature has heaped her most costly gifts should pity those to whom these gifts have been refused; but, in their character of experts, they may feel their superiority without pride. A beautiful woman would be as foolish to think herself ugly, as an intelligent man to think himself a fool. An exaggerated modesty (a rare fault, to be sure) is a kind of ingratitude towards nature. An honest pride, on the contrary, is the mark of a strong and beautiful soul, revealed by manly features moulded by feeling. If one's organism is an advantage, and the preeminent advantage, and the source of all others, education is the second. The best made brain would be a total loss without it, just as the best constituted man would be but a common peasant, without knowledge of the ways of the world. But, on the other hand, what would be the use of the most excellent school, without a matrix perfectly open to the entrance and conception of ideas? It is ... impossible to impart a single idea to a man deprived of all his senses.... But if the brain is at the same time well organized and well educated, it is a fertile soil, well sown, that brings forth a hundredfold what it has received: or (to leave the figures of speech often needed to express what one means, and to add grace to truth itself) the imagination, raised by art to the rare and beautiful dignity of genius, apprehends exactly all the relations of the ideas it has conceived, and takes in easily an astounding number of objects, in order to deduce from them a long chain of consequences, which are again but new relations, produced by a comparison with the first, to which the soul finds a perfect resemblance. Such is, I think, the generation of intelligence.{33} I say "finds" as I before gave the epithet "apparent" to the likeness of objects, not because I think that our senses are always deceivers, as Father Malebranche has claimed, or that our eyes, naturally a little unsteady, fail to see objects as they are in themselves, (though microscopes prove this to us every day) but in order to avoid any dispute with the Pyrrhonians,{34} among whom Bayle{35} is well known. I say of truth in general what M. de Fontenelle says of certain truths in particular, that we must sacrifice it in order to remain on good terms with society. And it accords with the gentleness of my character, to avoid all disputes unless to whet conversation. The Cartesians would here in vain make an onset upon me with their innate ideas. I certainly would not give myself a quarter of the trouble that M. Locke took, to attack such chimeras. In truth, what is the use of writing a ponderous volume to prove a doctrine which became an axiom three thousand years ago? According to the principles which we have laid down, and which we consider true; he who has the most imagination should be regarded as having the most intelligence or genius, for all these words are synonymous; and again, only by a shameful abuse [of terms] do we think that we are saying different things, when we are merely using different words, different sounds, to which no idea or real distinction is attached. The finest, greatest, or strongest imagination is then the one most suited to the sciences as well as to the arts. I do not pretend to say whether more intellect is necessary to excel in the art of Aristotle or of Descartes than to excel in that of Euripides or of Sophocles, and whether nature has taken more trouble to make Newton than to make Corneille, though I doubt this. But it is certain that imagination alone, differently applied, has produced their diverse triumphs and their immortal glory. If one is known as having little judgment and much imagination, this means that the imagination has been left too much alone, has, as it were, occupied most of the time in looking at itself in the mirror of its sensations, has not sufficiently formed the habit of examining the sensations themselves attentively. [It means that the imagination] has been more impressed by images than by their truth or their likeness. Truly, so quick are the responses of the imagination that if attention, that key or mother of the sciences, does not do its part, imagination can do little more than run over and skim its objects. See that bird on the bough: it seems always ready to fly away. Imagination is like the bird, always carried onward by the turmoil of the blood and the animal spirits. One wave leaves a mark, effaced by the one that follows; the soul pursues it, often in vain: it must expect to regret the loss of that which it has not quickly enough seized and fixed. Thus, imagination, the true image of time, is being ceaselessly destroyed and renewed. Such is the chaos and the continuous quick succession of our ideas: they drive each other away even as one wave yields to another. Therefore, if imagination does not, as it were, use one set of its muscles to maintain a kind of equilibrium with the fibres of the brain, to keep its attention for a while upon an object that is on the point of disappearing, and to prevent itself from contemplating prematurely another object--[unless the imagination does all this], it will never be worthy of the fine name of judgment. It will express vividly what it has perceived in the same fashion: it will create orators, musicians, painters, poets, but never a single philosopher. On the contrary, if the imagination be trained from childhood to bridle itself and to keep from being carried away by its own impetuosity--an impetuosity which creates only brilliant enthusiasts--and to check, to restrain, its ideas, to examine them in all their aspects in order to see all sides of an object, then the imagination, ready in judgment, will comprehend the greatest possible sphere of objects, through reasoning; and its vivacity (always so good a sign in children, and only needing to be regulated by study and training) will be only a far-seeing insight without which little progress can be made in the sciences. Such are the simple foundations upon which the edifice of logic has been reared. Nature has built these foundations for the whole human race, but some have used them, while others have abused them. In spite of all these advantages of man over animals, it is doing him honor to place him in the same class. For, truly, up to a certain age, he is more of an animal than they, since at birth he has less instinct. What animal would die of hunger in the midst of a river of milk? Man alone. Like that child of olden time to whom a modern writer, refers, following Arnobius,{36} he knows neither the foods suitable for him, nor the water that can drown him, nor the fire that can reduce him to ashes. Light a wax candle for the first time under a child's eyes, and he will mechanically put his fingers in the flame as if to find out what is the new thing that he sees. It is at his own cost that he will learn of the danger, but he will not be caught again. Or, put the child with an animal on a precipice, the child alone falls off; he drowns where the animal would save itself by swimming. At fourteen or fifteen years the child knows hardly anything of the great pleasures in store for him, in the reproduction of his species; when he is a youth, he does not know exactly how to behave in a game which nature teaches animals so quickly. He hides himself as if he were ashamed of taking pleasure, and of having been made to be happy, while animals frankly glory in being cynics. Without education, they are without prejudices. For one more example, let us observe a dog and a child who have lost their master on a highway: the child cries and does not know to what saint to pray, while the dog, better helped by his sense of smell than the child by his reason, soon finds his master. Thus nature made us to be lower than animals or at least to exhibit all the more, because of that native inferiority, the wonderful efficacy of education which alone raises us from the level of the animals and lifts us above them. But shall we grant this same distinction to the deaf and to the blind, to imbeciles, madmen, or savages, or to those who have been brought up in the woods with animals; to those who have lost their imagination through melancholia, or in short to all those animals in human form who give evidence of only the rudest instinct? No, all these, men of body but not of mind, do not deserve to be classed by themselves. We do not intend to hide from ourselves the arguments that can be brought forward against our belief and in favor of a primitive distinction between men and animals. Some say that there is in man a natural law, a knowledge of good and evil, which has never been imprinted on the heart of animals. But is this objection, or rather this assertion, based on observation? Any assertion unfounded on observation may be rejected by a philosopher. Have we ever had a single experience which convinces us that man alone has been enlightened by a ray denied all other animals? If there is no such experience, we can no more know what goes on in animals' minds or even in the minds of other men, than we can help feeling what affects the inner part of our own being. We know that we think, and feel remorse--an intimate feeling forces us to recognize this only too well; but this feeling in us is insufficient to enable us to judge the remorse of others. That is why we have to take others at their word, or judge them by the sensible and external signs we have noticed in ourselves when we experienced the same accusations of conscience and the same torments. In order to decide whether animals which do not talk have received the natural law, we must, therefore, have recourse to those signs to which I have just referred, if any such exist. The facts seem to prove it. A dog that bit the master who was teasing it, seemed to repent a minute afterwards; it looked sad, ashamed, afraid to show itself, and seemed to confess its guilt by a crouching and downcast air. History offers us a famous example of a lion which would not devour a man abandoned to its fury, because it recognized him as its benefactor. How much might it be wished that man himself always showed the same gratitude for kindnesses, and the same respect for humanity! Then we should no longer fear either ungrateful wretches, or wars which are the plague of the human race and the real executioners of the natural law. But a being to which nature has given such a precocious and enlightened instinct, which judges, combines, reasons, and deliberates as far as the sphere of its activity extends and permits, a being which feels attachment because of benefits received, and which leaving a master who treats it badly goes to seek a better one, a being with a structure like ours, which performs the same acts, has the same passions, the same griefs, the same pleasures, more or less intense according to the sway of the imagination and the delicacy of the nervous organization--does not such a being show clearly that it knows its faults and ours, understands good and evil, and in a word, has consciousness of what it does? Would its soul, which feels the same joys, the same mortification and the same discomfiture which we feel, remain utterly unmoved by disgust when it saw a fellow-creature torn to bits, or when it had itself pitilessly dismembered this fellow-creature? If this be granted, it follows that the precious gift now in question would not have been denied to animals: for since they show us sure signs of repentance, as well as of intelligence, what is there absurd in thinking that beings, almost as perfect machines as ourselves, are, like us, made to understand and to feel nature? Let no one object that animals, for the most part, are savage beasts, incapable of realizing the evil that they do; for do all men discriminate better between vice and virtue? There is ferocity in our species as well as in theirs. Men who are in the barbarous habit of breaking the natural law are not tormented as much by it, as those who transgress it for the first time, and who have not been hardened by the force of habit. The same thing is true of animals as of men--both may be more or less ferocious in temperament, and both become more so by living with others like themselves. But a gentle and peaceful animal which lives among other animals of the same disposition and of gentle nurture, will be an enemy of blood and carnage; it will blush internally at having shed blood. There is perhaps this difference, that since among animals everything is sacrificed to their needs, to their pleasures, to the necessities of life, which they enjoy more than we, their remorse apparently should not be as keen as ours, because we are not in the same state of necessity as they. Custom perhaps dulls and perhaps stifles remorse as well as pleasures. But I will suppose for a moment that I am utterly mistaken in concluding that almost all the world holds a wrong opinion on this subject, while I alone am right. I will grant that animals, even the best of them, do not know the difference between moral good and evil, that they have no recollection of the trouble taken for them, of the kindness done them, no realization of their own virtues. [I will suppose], for instance, that this lion, to which I, like so many others, have referred, does not remember at all that it refused to kill the man, abandoned to its fury, in a combat more inhuman than one could find among lions, tigers and bears, put together. For our compatriots fight, Swiss against Swiss, brother against brother, recognize each other, and yet capture and kill each other without remorse, because a prince pays for the murder. I suppose in short that the natural law has not been given animals. What will be the consequences of this supposition? Man is not moulded from a costlier clay; nature has used but one dough, and has merely varied the leaven. Therefore if animals do not repent for having violated this inmost feeling which I am discussing, or rather if they absolutely lack it, man must necessarily be in the same condition. Farewell then to the natural law and all the fine treatises published about it! The whole animal kingdom in general would be deprived of it. But, conversely, if man can not dispense with the belief that when health permits him to be himself, he always distinguishes the upright, humane, and virtuous, from those who are not humane, virtuous, nor honorable: that it is easy to tell vice from virtue, by the unique pleasure and the peculiar repugnance that seem to be their natural effects, it follows that animals, composed of the same matter, lacking perhaps only one degree of fermentation to make it exactly like man's, must share the same prerogatives of animal nature, and that thus there exists no soul or sensitive substance without remorse.{37} The following consideration will reinforce these observations. It is impossible to destroy the natural law. The impress of it on all animals is so strong, that I have no doubt that the wildest and most savage have some moments of repentance. I believe that that cruel maid of Chalons in Champagne must have sorrowed for her crime, if she really ate her sister. I think that the same thing is true of all those who commit crimes, even involuntary or temperamental crimes: true of Gaston of Orleans who could not help stealing; of a certain woman who was subject to the same crime when pregnant, and whose children inherited it; of the woman who, in the same condition, ate her husband; of that other woman who killed her children, salted their bodies, and ate a piece of them every day, as a little relish; of that daughter of a thief and cannibal who at twelve years followed in his steps, although she had been orphaned when she was a year old, and had been brought up by honest people; to say nothing of many other examples of which the records of our observers are full, all of them proving that there are a thousand hereditary vices and virtues which are transmitted from parents to children as those of the foster mother pass to the children she nurses. Now, I believe and admit that these wretches do not for the most part feel at the time the enormity of their actions. Bulimia, or canine hunger, for example, can stifle all feeling; it is a mania of the stomach that one is compelled to satisfy, but what remorse must be in store for those women, when they come to themselves and grow sober, and remember the crimes they have committed against those they held most dear! What a punishment for an involuntary crime which they could not resist, of which they had no consciousness whatever! However, this is apparently not enough for the judges. For of these women, of whom I tell, one was cruelly beaten and burned, and another was buried alive. I realize all that is demanded by the interest of society. But doubtless it is much to be wished that excellent physicians might be the only judges. They alone could tell the innocent criminal from the guilty. If reason is the slave of a depraved or mad desire, how can it control the desire? But if crime carries with it its own more or less cruel punishment, if the most continued and most barbarous habit can not entirely blot out repentance in the crudest hearts, if criminals are lacerated by the very memory of their deeds, why should we frighten the imagination of weak minds, by a hell, by specters, and by precipices of fire even less real than those of Pascal? [15] Why must we have recourse to fables, as an honest pope once said himself, to torment even the unhappy wretches who are executed, because we do not think that they are sufficiently punished by their own conscience, their first executioner? I do not mean to say that all criminals are unjustly punished; I only maintain that those whose will is depraved, and whose conscience is extinguished, are punished enough by their remorse when they come to themselves, a remorse, I venture to assert, from which nature should in this case have delivered unhappy souls dragged on by a fatal necessity. Criminals, scoundrels, ingrates, those in short without natural feelings, unhappy tyrants who are unworthy of life, in vain take a cruel pleasure in their barbarity, for there are calm moments of reflection in which the avenging conscience arises, testifies against them, and condemns them to be almost ceaselessly torn to pieces at their own hands. Whoever torments men is tormented by himself; and the sufferings that he will experience will be the just measure of those that he has inflicted. On the other hand, there is so much pleasure in doing good, in recognizing and appreciating what one receives, so much satisfaction in practising virtue, in being gentle, humane, kind, charitable, compassionate and generous (for this one word includes all the virtues), that I consider as sufficiently punished any one who is unfortunate enough not to have been born virtuous. We were not originally made to be learned; we have become so perhaps by a sort of abuse of our organic faculties, and at the expense of the State which nourishes a host of sluggards whom vanity has adorned with the name of philosophers. Nature has created us all solely to be happy{38}--yes, all of us from the crawling worm to the eagle lost in the clouds. For this cause she has given all animals some share of natural law, a share greater or less according to the needs of each animal's organs when in normal condition. Now how shall we define natural law? It is a feeling that teaches us what we should not do, because we would not wish it to be done to us. Should I dare add to this common idea, that this feeling seems to me but a kind of fear or dread, as salutary to the race as to the individual; for may it not be true that we respect the purse and life of others only to save our own possessions, our honor, and ourselves; like those Ixions of Christianity{39} who love God and embrace so many fantastic virtues, merely because they are afraid of hell! You see that natural law is but an intimate feeling that, like all other feelings (thought included), belongs also to imagination. Evidently, therefore, natural law does not presuppose education, revelation, nor legislator,--provided one does not propose to confuse natural law with civil laws, in the ridiculous fashion of the theologians. The arms of fanaticism may destroy those who support these truths, but they will never destroy the truths themselves. I do not mean to call in question the existence of a supreme being; on the contrary it seems to me that the greatest degree of probability is in favor of this belief. But since the existence of this being goes no further than that of any other toward proving the need of worship, it is a theoretic truth with very little practical value. Therefore, since we may say, after such long experience, that religion does not imply exact honesty, we are authorized by the same reasons to think that atheism does not exclude it. Furthermore, who can be sure that the reason for man's existence is not simply the fact that he exists?{40} Perhaps he was thrown by chance on some spot on the earth's surface, nobody knows how nor why, but simply that he must live and die, like the mushrooms which appear from day to day, or like those flowers which border the ditches and cover the walls. Let us not lose ourselves in the infinite, for we are not made to have the least idea thereof, and are absolutely unable to get back to the origin of things. Besides it does not matter for our peace of mind, whether matter be eternal or have been created, whether there be or be not a God. How foolish to torment ourselves so much about things which we can not know, and which would not make us any happier even were we to gain knowledge about them! But, some will say, read all such works as those of Fénelon,{41} of Nieuwentyt,{42} of Abadie,{43} of Derham,{44} of Rais,{45} and the rest. Well! what will they teach me or rather what have they taught me? They are only tiresome repetitions of zealous writers, one of whom adds to the other only verbiage, more likely to strengthen than to undermine the foundations of atheism. The number of the evidences drawn from the spectacle of nature does not give these evidences any more force. Either the mere structure of a finger, of an ear, of an eye, a single observation of Malpighi{46} proves all, and doubtless much better than Descartes and Malebranche proved it, or all the other evidences prove nothing. Deists,{47} and even Christians, should therefore be content to point out that throughout the animal kingdom the same aims are pursued and accomplished by an infinite number of different mechanisms, all of them however exactly geometrical. For what stronger weapons could there be with which to overthrow atheists? It is true that if my reason does not deceive me, man and the whole universe seem to have been designed for this unity of aim. The sun, air, water, the organism, the shape of bodies,--everything is brought to a focus in the eye as in a mirror that faithfully presents to the imagination all the objects reflected in it, in accordance with the laws required by the infinite variety of bodies which take part in vision. In ears we find everywhere a striking variety, and yet the difference of structure in men, animals, birds, and fishes, does not produce different uses. All ears are so mathematically made, that they tend equally to one and the same end, namely, hearing. But would Chance, the deist asks, be a great enough geometrician to vary thus, at pleasure, the works of which she is supposed to be the author, without being hindered by so great a diversity from gaining the same end? Again, the deist will bring forward as a difficulty those parts of the animal that are clearly contained in it for future use, the butterfly in the caterpillar, man in the sperm, a whole polyp in each of its parts, the valvule in the oval orifice, the lungs in the foetus, the teeth in their sockets, the bones in the fluid from which they detach themselves and (in an incomprehensible manner) harden. And since the partisans of this theory, far from neglecting anything that would strengthen it, never tire of piling up proof upon proof, they are willing to avail themselves of everything, even of the weakness of the mind in certain cases. Look, they say, at men like Spinoza, Vanini,{48} Desbarreau,{49} and Boindin,{50} apostles who honor deism more than they harm it. The duration of their health was the measure of their unbelief, and one rarely fails, they add, to renounce atheism when the passions, with their instrument, the body, have grown weak. That is certainly the most that can be said in favor of the existence of God: although the last argument is frivolous in that these conversions are short, and the mind almost always regains its former opinions and acts accordingly, as soon as it has regained or rather rediscovered its strength in that of the body. That is, at least, much more than was said by the physician Diderot,{51} in his "Pensées Philosophiques," a sublime work that will not convince a single atheist. What reply can, in truth, be made to a man who says, "We do not know nature; causes hidden in her breast might have produced everything. In your turn, observe the polyp of Trembley:{52} does it not contain in itself the causes which bring about regeneration? Why then would it be absurd to think that there are physical causes by reason of which everything has been made, and to which the whole chain of this vast universe is so necessarily bound and held that nothing which happens, could have failed to happen,{53}--causes, of which we are so invincibly ignorant that we have had recourse to a God, who, as some aver, is not so much as a logical entity? Thus to destroy chance is not to prove the existence of a supreme being, since there may be some other thing which is neither chance nor God--I mean, nature. It follows that the study of nature can make only unbelievers; and the way of thinking of all its more successful investigators proves this." The weight of the universe therefore far from crushing a real atheist does not even shake him. All these evidences of a creator, repeated thousands and thousands of times, evidences that are placed far above the comprehension of men like us, are self-evident (however far one push the argument) only to the anti-Pyrrhonians,{54} or to those who have enough confidence in their reason to believe themselves capable of judging on the basis of certain phenomena, against which, as you see, the atheists can urge others perhaps equally strong and absolutely opposed. For if we listen to the naturalists again, they will tell us that the very causes which, in a chemist's hands, by a chance combination, made the first mirror, in the hands of nature made the pure water, the mirror of the simple shepherdess; that the motion which keeps the world going could have created it, that each body has taken the place assigned to it by its own nature, that the air must have surrounded the earth, and that iron and the other metals are produced by internal motions of the earth, for one and the same reason; that the sun is as much a natural product as electricity, that it was not made to warm the earth and its inhabitants, whom it sometimes burns, any more than the rain was made to make the seeds grow, which it often spoils; that the mirror and the water were no more made for people to see themselves in, than were all other polished bodies with this same property; that the eye is in truth a kind of glass in which the soul can contemplate the image of objects as they are presented to it by these bodies, but that it is not proved that this organ was really made expressly for this contemplation, nor purposely placed in its socket, and in short that it may well be that Lucretius,{55} the physician Lamy,{56} and all Epicureans both ancient and modern were right when they suggested that the eye sees only because it is formed and placed as it is,{57} and that, given once for all, the same rules of motion followed by nature in the generation and development of bodies, this marvelous organ could not have been formed and placed differently. Such is the pro and the con, and the summary of those fine arguments that will eternally divide the philosophers. I do not take either side. "Non nostrum inter vos tantas componere lites."{58} This is what I said to one of my friends, a Frenchman, as frank a Pyrronian as I, a man of much merit, and worthy of a better fate. He gave me a very singular answer in regard to the matter. "It is true," he told me, "that the pro and con should not disturb at all the soul of a philosopher, who sees that nothing is proved with clearness enough to force his consent, and that the arguments offered on one side are neutralized by those of the other. However," he continued, "the universe will never be happy, unless it is atheistic."{59} Here are this wretch's reasons. If atheism, said he, were generally accepted, all the forms of religion would then be destroyed and cut off at the roots. No more theological wars, no more soldiers of religion--such terrible soldiers! Nature infected with a sacred poison, would regain its rights and its purity. Deaf to all other voices, tranquil mortals would follow only the spontaneous dictates of their own being the only commands which can never be despised with impunity and which alone can lead us to happiness through the pleasant paths of virtue. Such is natural law: whoever rigidly observes it is a good man and deserves the confidence of all the human race. Whoever fails to follow it scrupulously affects, in vain, the specious exterior of another religion; he is a scamp or a hypocrite whom I distrust. After this, let a vain people think otherwise, let them dare affirm that even probity is at stake in not believing in revelation, in a word that another religion than that of nature is necessary, whatever it may be. Such an assertion is wretched and pitiable; and so is the good opinion which each one gives us of the religion he has embraced! We do not seek here the votes of the crowd. Whoever raises in his heart altars to superstition, is born to worship idols and not to thrill to virtue. But since all the faculties of the soul depend to such a degree on the proper organization of the brain and of the whole body, that apparently they are but this organization itself, the soul is clearly an enlightened machine. For finally, even if man alone had received a share of natural law, would he be any less a machine for that? A few more wheels, a few more springs than in the most perfect animals, the brain proportionally nearer the heart and for this very reason receiving more blood--any one of a number of unknown causes might always produce this delicate conscience so easily wounded, this remorse which is no more foreign to matter than to thought, and in a word all the differences that are supposed to exist here. Could the organism then suffice for everything? Once more, yes; since thought visibly develops with our organs, why should not the matter of which they are composed be susceptible of remorse also, when once it has acquired, with time, the faculty of feeling? The soul is therefore but an empty word, of which no one has any idea, and which an enlightened man should use only to signify the part in us that thinks.{60} Given the least principle of motion, animated bodies will have all that is necessary for moving, feeling, thinking, repenting, or in a word for conducting themselves in the physical realm, and in the moral realm which depends upon it. Yet we take nothing for granted; those who perhaps think that all the difficulties have not yet been removed shall now read of experiments that will completely satisfy them. 1. The flesh of all animals palpitates after death. This palpitation continues longer, the more cold blooded the animal is and the less it perspires. Tortoises, lizards, serpents, etc. are evidence of this. 2. Muscles separated from the body contract when they are stimulated. 3. The intestines keep up their peristaltic or vermicular motion for a long time. 4. According to Cowper,{61} a simple injection of hot water reanimates the heart and the muscles. 5. A frog's heart moves for an hour or more after it has been removed from the body, especially when exposed to the sun or better still when placed on a hot table or chair. If this movement seems totally lost, one has only to stimulate the heart, and that hollow muscle beats again. Harvey{62} made this same observation on toads. 6. Bacon of Verulam{63} in his treatise "Sylva Sylvarum" cites the case of a man convicted of treason, who was opened alive, and whose heart thrown into hot water leaped several times, each time less high, to the perpendicular height of two feet. 7. Take a tiny chicken still in the egg, cut out the heart and you will observe the same phenomena as before, under almost the same conditions. The warmth of the breath alone reanimates an animal about to perish in the air pump. The same experiments, which we owe to Boyle{64} and to Sténon,{65} are made on pigeons, dogs, and rabbits. Pieces of their hearts beat as their whole hearts would. The same movements can be seen in paws that have been cut off from moles. 8. The caterpillar, the worm, the spider, the fly, the eel--all exhibit the same phenomena; and in hot water, because of the fire it contains, the movement of the detached parts increases. 9. A drunken soldier cut off with one stroke of his sabre an Indian rooster's head. The animal remained standing, then walked, and ran: happening to run against a wall, it turned around, beat its wings still running, and finally fell down. As it lay on the ground, all the muscles of this rooster kept on moving. That is what I saw myself, and almost the same phenomena can easily be observed in kittens or puppies with their heads cut off. 10. Polyps do more than move after they have been cut in pieces. In a week they regenerate to form as many animals as there are pieces. I am sorry that these facts speak against the naturalists' system of generation; or rather I am very glad of it, for let this discovery teach us never to reach a general conclusion even on the ground of all known (and most decisive) experiments. Here we have many more facts than are needed to prove, in an incontestable way, that each tiny fibre or part of an organized body moves by a principle which belongs to it. Its activity, unlike voluntary motions, does not depend in any way on the nerves, since the movements in question occur in parts of the body which have no connection with the circulation. But if this force is manifested even in sections of fibres the heart, which is a composite of peculiarly connected fibres, must possess the same property. I did not need Bacon's story to persuade me of this. It was easy for me to come to this conclusion, both from the perfect analogy of the structure of the human heart with that of animals, and also from the very bulk of the human heart, in which this movement escapes our eyes only because it is smothered, and finally because in corpses all the organs are cold and lifeless. If executed criminals were dissected while their bodies are still warm, we should probably see in their hearts the same movements that are observed in the face-muscles of those that have been beheaded. The motive principle of the whole body, and even of its parts cut in pieces, is such that it produces not irregular movements, as some have thought, but very regular ones, in warm blooded and perfect animals as well as in cold and imperfect ones. No resource therefore remains open to our adversaries but to deny thousands and thousands of facts which every man can easily verify. If now any one ask me where is this innate force in our bodies, I answer that it very clearly resides in what the ancients called the parenchyma, that is to say, in the very substance of the organs not including the veins, the arteries, the nerves, in a word, that it resides in the organization of the whole body, and that consequently each organ contains within itself forces more or less active according to the need of them. Let us now go into some detail concerning these springs of the human machine. All the vital, animal, natural, and automatic motions are carried on by their action. Is it not in a purely mechanical way that the body shrinks back when it is struck with terror at the sight of an unforeseen precipice, that the eyelids are lowered at the menace of a blow, as some have remarked, and that the pupil contracts in broad daylight to save the retina, and dilates to see objects in darkness? Is it not by mechanical means that the pores of the skin close in winter so that the cold can not penetrate to the interior of the blood vessels, and that the stomach vomits when it is irritated by poison, by a certain quantity of opium and by all emetics, etc.? that the heart, the arteries and the muscles contract in sleep as well as in waking hours, that the lungs serve as bellows continually in exercise, ... that the heart contracts more strongly than any other muscle?{66}... I shall not go into any more detail concerning all these little subordinate forces, well known to all. But there is another more subtle and marvelous force, which animates them all; it is the source of all our feelings, of all our pleasures, of all our passions, and of all our thoughts: for the brain has its muscles for thinking, as the legs have muscles for walking.{67} I wish to speak of this impetuous principle that Hippocrates calls enormôn (soul). This principle exists and has its seat in the brain at the origin of the nerves, by which it exercises its control over all the rest of the body. By this fact is explained all that can be explained, even to the surprising effects of maladies of the imagination.... Look at the portrait of the famous Pope who is, to say the least, the Voltaire of the English. The effort, the energy of his genius are imprinted upon his countenance. It is convulsed. His eyes protrude from their sockets, the eyebrows are raised with the muscles of the forehead. Why? Because the brain is in travail and all the body must share in such a laborious deliverance. If there were not an internal cord which pulled the external ones, whence would come all these phenomena? To admit a soul as explanation of them, is to be reduced to [explaining phenomena by] the operations of the Holy Spirit. In fact, if what thinks in my brain is not a part of this organ and therefore of the whole body, why does my blood boil, and the fever of my mind pass into my veins, when lying quietly in bed, I am forming the plan of some work or carrying on an abstract calculation? Put this question to men of imagination, to great poets, to men who are enraptured by the felicitous expression of sentiment, and transported by an exquisite fancy or by the charms of nature, of truth, or of virtue! By their enthusiasm, by what they will tell you they have experienced, you will judge the cause by its effects; by that harmony which Borelli,{68} a mere anatomist, understood better than all the Leibnizians, you will comprehend the material unity of man. In short, if the nerve-tension which causes pain occasions also the fever by which the distracted mind loses its will-power, and if, conversely, the mind too much excited, disturbs the body (and kindles that inner fire which killed Bayle while he was still so young); if an agitation rouses my desire and my ardent wish for what, a moment ago, I cared nothing about, and if in their turn certain brain impressions excite the same longing and the same desires, then why should we regard as double what is manifestly one being? In vain you fall back on the power of the will, since for one order that the will gives, it bows a hundred times to the yoke.{69} And what wonder that in health the body obeys, since a torrent of blood and of animal spirits{70} forces its obedience, and since the will has as ministers an invisible legion of fluids swifter than lightning and ever ready to do its bidding! But as the power of the will is exercised by means of the nerves, it is likewise limited by them..... Does the result of jaundice surprise you? Do you not know that the color of bodies depends on the color of the glasses through which we look at them,{71} and that whatever is the color of the humors, such is the color of objects, at least for us, vain playthings of a thousand illusions? But remove this color from the aqueous humor of the eye, let the bile flow through its natural filter, then the soul having new eyes, will no longer see yellow. Again, is it not thus, by removing cataract, or by injecting the Eustachian canal, that sight is restored to the blind, or hearing to the deaf? How many people, who were perhaps only clever charlatans, passed for miracle workers in the dark ages! Beautiful the soul, and powerful the will which can not act save by permission of the bodily conditions, and whose tastes change with age and fever! Should we, then, be astonished that philosophers have always had in mind the health of the body, to preserve the health of the soul, that Pythagoras{72} gave rules for the diet as carefully as Plato forbade wine?{73} The regime suited to the body is always the one with which sane physicians think they must begin, when it is a question of forming the mind, and of instructing it in the knowledge of truth and virtue; but these are vain words in the disorder of illness, and in the tumult of the senses. Without the precepts of hygiene, Epictetus, Socrates, Plato, and the rest preach in vain: all ethics is fruitless for one who lacks his share of temperance; it is the source of all virtues, as intemperance is the source of all vices. Is more needed, (for why lose myself in discussion of the passions which are all explained by the term, enormôn, of Hippocrates) to prove that man is but an animal, or a collection of springs which wind each other up, without our being able to tell at what point in this human circle, nature has begun? If these springs differ among themselves, these differences consist only in their position and in their degrees of strength, and never in their nature; wherefore the soul is but a principle of motion or a material and sensible part of the brain, which can be regarded, without fear of error, as the mainspring of the whole machine, having a visible influence on all the parts. The soul seems even to have been made for the brain, so that all the other parts of the system are but a kind of emanation from the brain. This will appear from certain observations, made on different embryos, which I shall now enumerate. This oscillation, which is natural or suited to our machine, and with which each fibre and even each fibrous element, so to speak, seems to be endowed, like that of a pendulum, can not keep up forever. It must be renewed, as it loses strength, invigorated when it is tired, and weakened when it is disturbed by excess of strength and vigor. In this alone, true medicine consists. The body is but a watch, whose watchmaker is the new chyle. Nature's first care, when the chyle enters the blood, is to excite in it a kind of fever{74} which the chemists, who dream only of retorts, must have taken for fermentation. This fever produces a greater filtration of spirits, which mechanically animate the muscles and the heart, as if they had been sent there by order of the will. These then are the causes or the forces of life which thus sustain for a hundred years that perpetual movement of the solids and the liquids which is as necessary to the first as to the second. But who can say whether the solids contribute more than the fluids to this movement or vice versa? All that we know is that the action of the former would soon cease without the help of the latter, that is, without the help of the fluids which by their onset rouse and maintain the elasticity of the blood vessels on which their own circulation depends. From this it follows that after death the natural resilience of each substance is still more or less strong according to the remnants of life which it outlives, being the last to perish. So true is it that this force of the animal parts can be preserved and strengthened by that of the circulation, but that it does not depend on the strength of the circulation, since, as we have seen, it can dispense with even the integrity of each member or organ. I am aware that this opinion has not been relished by all scholars, and that Stahl especially had much scorn for it. This great chemist has wished to persuade us that the soul is the sole cause of all our movements. But this is to speak as a fanatic and not as a philosopher. To destroy the hypothesis of Stahl,{75} we need not make as great an effort as I find that others have done before me. We need only glance at a violinist. What flexibility, what lightness in his fingers! The movements are so quick, that it seems almost as if there were no succession. But I pray, or rather I challenge, the followers of Stahl who understand so perfectly all that our soul can do, to tell me how it could possibly execute so many motions so quickly, motions, moreover, which take place so far from the soul, and in so many different places. That is to suppose that a flute player could play brilliant cadences on an infinite number of holes that he could not know, and on which he could not even put his finger! But let us say with M. Hecquet{76} that all men may not go to Corinth.{77} Why should not Stahl have been even more favored by nature as a man than as a chemist and a practitioner? Happy mortal, he must have received a soul different from that of the rest of mankind,--a sovereign soul, which, not content with having some control over the voluntary muscles, easily held the reins of all the movements of the body, and could suspend them, calm them, or excite them, at its pleasure! With so despotic a mistress, in whose hands were, in a sense, the beating of the heart, and the laws of circulation, there could certainly be no fever, no pain, no weariness,...! The soul wills, and the springs play, contract or relax. But how did the springs of Stahl's machine get out of order so soon? He who has in himself so great a doctor, should be immortal. Moreover, Stahl is not the only one who has rejected the principle of the vibration of organic bodies. Greater minds have not used the principle when they wished to explain the action of the heart, ... etc. One need only read the "Institutions of Medicine" by Boerhaave{78} to see what laborious and enticing systems this great man was obliged to invent, by the labor of his mighty genius, through failure to admit that there is so wonderful a force in all bodies. Willis{79} and Perrault,{80} minds of a more feeble stamp, but careful observers of nature (whereas nature was known to the famous Leyden professor only through others and second hand, so to speak) seem to have preferred to suppose a soul generally extended over the whole body, instead of the principle which we are describing. But according to this hypothesis (which was the hypothesis of Vergil and of all Epicureans, an hypothesis which the history of the polyp might seem at first sight to favor) the movements which go on after the death of the subject in which they inhere are due to a remnant of soul still maintained by the parts that contract, though, from the moment of death, these are not excited by the blood and the spirits. Whence it may be seen that these writers, whose solid works easily eclipse all philosophic fables, are deceived only in the manner of those who have endowed matter with the faculty of thinking, I mean to say, by having expressed themselves badly in obscure and meaningless terms. In truth, what is this remnant of a soul, if it is not the "moving force" of the Leibnizians (badly rendered by such an expression), which however Perrault in particular has really foreseen. See his "Treatise on the Mechanism of Animals." Now that it is clearly proved against the Cartesians, the followers of Stahl, the Malebranchists, and the theologians who little deserve to be mentioned here, that matter is self-moved,{81} not only when organized, as in a whole heart, for example, but even when this organization has been destroyed, human curiosity would like to discover how a body, by the fact that it is originally endowed with the breath of life, finds itself adorned in consequence with the faculty of feeling, and thus with that of thought. And, heavens, what efforts have not been made by certain philosophers to manage to prove this! and what nonsense on this subject I have had the patience to read! All that experience teaches us is that while movement persists, however slight it may be, in one or more fibres, we need only stimulate them to re-excite and animate this movement almost extinguished. This has been shown in the host of experiments with which I have undertaken to crush the systems. It is therefore certain that motion and feeling excite each other in turn, both in a whole body and in the same body when its structure is destroyed, to say nothing of certain plants which seem to exhibit the same phenomena of the union of feeling and motion. But furthermore, how many excellent philosophers have shown that thought is but a faculty of feeling, and that the reasonable soul is but the feeling soul engaged in contemplating its ideas and in reasoning! This would be proved by the fact alone that when feeling is stifled, thought also is checked, for instance in apoplexy, in lethargy, in catalepsis, etc. For it is ridiculous to suggest that, during these stupors, the soul keeps on thinking, even though it does not remember the ideas that it has had. As to the development of feeling and motion, it is absurd to waste time seeking for its mechanism. The nature of motion is as unknown to us as that of matter.{82} How can we discover how it is produced unless, like the author of "The History of the Soul," we resuscitate the old and unintelligible doctrine of substantial forms? I am then quite as content not to know how inert and simple matter becomes active and highly organized, as not to be able to look at the sun without red glasses; and I am as little disquieted concerning the other incomprehensible wonders of nature, the production of feeling and of thought in a being which earlier appeared to our limited eyes as a mere clod of clay. Grant only that organized matter is endowed with a principle of motion, which alone differentiates it from the inorganic (and can one deny this in the face of the most incontestable observation?) and that among animals, as I have sufficiently proved, everything depends upon the diversity of this organization: these admissions suffice for guessing the riddle of substances and of man. It [thus] appears that there is but one [type of organization] in the universe, and that man is the most perfect [example]. He is to the ape, and to the most intelligent animals, as the planetary pendulum of Huyghens{83} is to a watch of Julien Leroy.{84} More instruments, more wheels and more springs were necessary to mark the movements of the planets than to mark or strike the hours; and Vaucanson,{85} who needed more skill for making his flute player than for making his duck, would have needed still more to make a talking man, a mechanism no longer to be regarded as impossible, especially in the hands of another Prometheus. In like fashion, it was necessary that nature should use more elaborate art in making and sustaining a machine which for a whole century could mark all motions of the heart and of the mind; for though one does not tell time by the pulse, it is at least the barometer of the warmth and the vivacity by which one may estimate the nature of the soul. I am right! The human body is a watch, a large watch constructed with such skill and ingenuity, that if the wheel which marks the seconds happens to stop, the minute wheel turns and keeps on going its round, and in the same way the quarter-hour wheel, and all the others go on running when the first wheels have stopped because rusty or, for any reason, out of order. Is it not for a similar reason that the stoppage of a few blood vessels is not enough to destroy or suspend the strength of the movement which is in the heart as in the mainspring of the machine; since, on the contrary, the fluids whose volume is diminished, having a shorter road to travel, cover the ground more quickly, borne on as by a fresh current which the energy of the heart increases in proportion to the resistance it encounters at the ends of the blood-vessels? And is not this the reason why the loss of sight (caused by the compression of the optic nerve and by its ceasing to convey the images of objects) no more hinders hearing, than the loss of hearing (caused by obstruction of the functions of the auditory nerve) implies the loss of sight? In the same way, finally, does not one man hear (except immediately after his attack) without being able to say that he hears, while another who hears nothing, but whose lingual nerves are uninjured in the brain, mechanically tells of all the dreams which pass through his mind? These phenomena do not surprise enlightened physicians at all. They know what to think about man's nature, and (more accurately to express myself in passing) of two physicians, the better one and the one who deserves more confidence is always, in my opinion, the one who is more versed in the physique or mechanism of the human body, and who, leaving aside the soul and all the anxieties which this chimera gives to fools and to ignorant men, is seriously occupied only in pure naturalism. Therefore let the pretended M. Charp deride philosophers who have regarded animals as machines. How different is my view! I believe that Descartes would be a man in every way worthy of respect, if, born in a century that he had not been obliged to enlighten, he had known the value of experiment and observation, and the danger of cutting loose from them. But it is none the less just for me to make an authentic reparation to this great man for all the insignificant philosophers--poor jesters, and poor imitators of Locke--who instead of laughing impudently at Descartes, might better realize that without him the field of philosophy, like the field of science without Newton, might perhaps be still uncultivated. This celebrated philosopher, it is true, was much deceived, and no one denies that. But at any rate he understood animal nature, he was the first to prove completely that animals are pure machines.{86} And after a discovery of this importance demanding so much sagacity, how can we without ingratitude fail to pardon all his errors! In my eyes, they are all atoned for by that great confession. For after all, although he extols the distinctness of the two substances, this is plainly but a trick of skill, a ruse of style, to make theologians swallow a poison, hidden in the shade of an analogy which strikes everybody else and which they alone fail to notice. For it is this, this strong analogy, which forces all scholars and wise judges to confess that these proud and vain beings, more distinguished by their pride than by the name of men however much they may wish to exalt themselves, are at bottom only animals and machines which, though upright, go on all fours. They all have this marvelous instinct, which is developed by education into mind, and which always has its seat in the brain, (or for want of that when it is lacking or hardened, in the medulla oblongata) and never in the cerebellum; for I have often seen the cerebellum injured, and other observers [16] have found it hardened, when the soul has not ceased to fulfil its functions. To be a machine, to feel, to think, to know how to distinguish good from bad, as well as blue from yellow, in a word, to be born with an intelligence and a sure moral instinct, and to be but an animal, are therefore characters which are no more contradictory, than to be an ape or a parrot and to be able to give oneself pleasure.... I believe that thought is so little incompatible with organized matter, that it seems to be one of its properties on a par with electricity, the faculty of motion, impenetrability, extension, etc. Do you ask for further observations? Here are some which are incontestable and which all prove that man resembles animals perfectly, in his origin as well as in all the points in which we have thought it essential to make the comparison.... Let us observe man both in and out of his shell, let us examine young embryos of four, six, eight or fifteen days with a microscope; after that time our eyes are sufficient. What do we see? The head alone; a little round egg with two black points which mark the eyes. Before that, everything is formless, and one sees only a medullary pulp, which is the brain, in which are formed first the roots of the nerves, that is, the principle of feeling, and the heart, which already within this substance has the power of beating of itself; it is the punctum saliens of Malpighi, which perhaps already owes a part of its excitability to the influence of the nerves. Then little by little, one sees the head lengthen from the neck, which, in dilating, forms first the thorax inside which the heart has already sunk, there to become stationary; below that is the abdomen which is divided by a partition (the diaphragm). One of these enlargements of the body forms the arms, the hands, the fingers, the nails, and the hair; the other forms the thighs, the legs, the feet, etc., which differ only in their observed situation, and which constitute the support and the balancing pole of the body. The whole process is a strange sort of growth, like that of plants. On the tops of our heads is hair in place of which the plants have leaves and flowers; everywhere is shown the same luxury of nature, and finally the directing principle of plants is placed where we have our soul, that other quintessence of man. Such is the uniformity of nature, which we are beginning to realize; and the analogy of the animal with the vegetable kingdom, of man with plant. Perhaps there even are animal plants, which in vegetating, either fight as polyps do, or perform other functions characteristic of animals.... We are veritable moles in the field of nature; we achieve little more than the mole's journey and it is our pride which prescribes limits to the limitless. We are in the position of a watch that should say (a writer of fables would make the watch a hero in a silly tale): "I was never made by that fool of a workman, I who divide time, who mark so exactly the course of the sun, who repeat aloud the hours which I mark! No! that is impossible!" In the same way, we disdain, ungrateful wretches that we are, this common mother of all kingdoms, as the chemists say. We imagine, or rather we infer, a cause superior to that to which we owe all, and which truly has wrought all things in an inconceivable fashion. No; matter contains nothing base, except to the vulgar eyes which do not recognize her in her most splendid works; and nature is no stupid workman. She creates millions of men, with a facility and a pleasure more intense than the effort of a watchmaker in making the most complicated watch. Her power shines forth equally in creating the lowliest insect and in creating the most highly developed man; the animal kingdom costs her no more than the vegetable, and the most splendid genius no more than a blade of wheat. Let us then judge by what we see of that which is hidden from the curiosity of our eyes and of our investigations, and let us not imagine anything beyond. Let us observe the ape, the beaver, the elephant, etc., in their operations. If it is clear that these activities can not be performed without intelligence, why refuse intelligence to these animals? And if you grant them a soul, you are lost, you fanatics! You will in vain say that you assert nothing about the nature of the animal soul and that you deny its immortality. Who does not see that this is a gratuitous assertion; who does not see that the soul of an animal must be either mortal or immortal, whichever ours [is], and that it must therefore undergo the same fate as ours, whatever that may be, and that thus [in admitting that animals have souls], you fall into Scylla in the effort to avoid Charybdis? Break the chain of your prejudices, arm yourselves with the torch of experience, and you will render to nature the honor she deserves, instead of inferring anything to her disadvantage, from the ignorance in which she has left you. Only open wide your eyes, only disregard what you can not understand, and you will see that the ploughman whose intelligence and ideas extend no further than the bounds of his furrow, does not differ essentially from the greatest genius,--a truth which the dissection of Descartes's and of Newton's brains would have proved; you will be persuaded that the imbecile and the fool are animals with human faces, as the intelligent ape is a little man in another shape; in short, you will learn that since everything depends absolutely on difference of organization, a well constructed animal which has studied astronomy, can predict an eclipse, as it can predict recovery or death when it has used its genius and its clearness of vision, for a time, in the school of Hippocrates and at the bedside of the sick. By this line of observations and truths, we come to connect the admirable power of thought with matter, without being able to see the links, because the subject of this attribute is essentially unknown to us. Let us not say that every machine or every animal perishes altogether or assumes another form after death, for we know absolutely nothing about the subject. On the other hand, to assert that an immortal machine is a chimera or a logical fiction, is to reason as absurdly as caterpillars would reason if, seeing the cast-off skins of their fellow-caterpillars, they should bitterly deplore the fate of their species, which to them would seem to come to nothing. The soul of these insects (for each animal has his own) is too limited to comprehend the metamorphoses of nature. Never one of the most skilful among them could have imagined that it was destined to become a butterfly. It is the same with us. What more do we know of our destiny than of our origin? Let us then submit to an invincible ignorance on which our happiness depends. He who so thinks will be wise, just, tranquil about his fate, and therefore happy. He will await death without either fear or desire, and will cherish life (hardly understanding how disgust can corrupt a heart in this place of many delights); he will be filled with reverence, gratitude, affection, and tenderness for nature, in proportion to his feeling of the benefits he has received from nature; he will be happy, in short, in feeling nature, and in being present at the enchanting spectacle of the universe, and he will surely never destroy nature either in himself or in others. More than that! Full of humanity, this man will love human character even in his enemies. Judge how he will treat others. He will pity the wicked without hating them; in his eyes, they will be but mis-made men. But in pardoning the faults of the structure of mind and body, he will none the less admire the beauties and the virtues of both. Those whom nature shall have favored will seem to him to deserve more respect than those whom she has treated in stepmotherly fashion. Thus, as we have seen, natural gifts, the source of all acquirements, gain from the lips and heart of the materialist, the homage which every other thinker unjustly refuses them. In short, the materialist, convinced, in spite of the protests of his vanity, that he is but a machine or an animal, will not maltreat his kind, for he will know too well the nature of those actions, whose humanity is always in proportion to the degree of the analogy proved above [between human beings and animals]; and following the natural law given to all animals, he will not wish to do to others what he would not wish them to do to him. Let us then conclude boldly that man is a machine, and that in the whole universe there is but a single substance differently modified. This is no hypothesis set forth by dint of a number of postulates and assumptions; it is not the work of prejudice, nor even of my reason alone; I should have disdained a guide which I think to be so untrustworthy, had not my senses, bearing a torch, so to speak, induced me to follow reason by lighting the way themselves. Experience has thus spoken to me in behalf of reason; and in this way I have combined the two. But it must have been noticed that I have not allowed myself even the most vigorous and immediately deduced reasoning, except as a result of a multitude of observations which no scholar will contest; and furthermore, I recognize only scholars as judges of the conclusions which I draw from the observations; and I hereby challenge every prejudiced man who is neither anatomist, nor acquainted with the only philosophy which can here be considered, that of the human body. Against so strong and solid an oak, what could the weak reeds of theology, of metaphysics, and of the schools, avail,--childish arms, like our parlor foils, that may well afford the pleasure of fencing, but can never wound an adversary. Need I say that I refer to the empty and trivial notions, to the pitiable and trite arguments that will be urged (as long as the shadow of prejudice or of superstition remains on earth) for the supposed incompatibility of two substances which meet and move each other unceasingly? Such is my system, or rather the truth, unless I am much deceived. It is short and simple. Dispute it now who will. THE NATURAL HISTORY OF THE SOUL. BY JEAN OFFRAY DE LA METTRIE. EXTRACTS. CHAPTER II. CONCERNING MATTER. All philosophers who have examined attentively the nature of matter, considered in itself, independently of all the forms which constitute bodies, have discovered in this substance, diverse properties proceeding from an absolutely unknown essence. Such are, (1) the capacity of taking on different forms, which are produced in matter itself, by which matter can acquire moving force and the faculty of feeling; (2) actual extension, which these philosophers have rightly recognized as an attribute, but not as the essence, of matter. However, there have been some, among others Descartes, who have insisted on reducing the essence of matter to simple extension, and on limiting all the properties of matter to those of extension; but this opinion has been rejected by all other modern philosophers, ... so that the power of acquiring moving force, and the faculty of feeling as well as that of extension, have been from all time considered as essential properties{87} of matter. All the diverse properties that are observed in this unknown principle demonstrate a being in which these same properties exist, a being which must therefore exist through itself. But we can not conceive, or rather it seems impossible, that a being which exists through itself should be able neither to create nor to annihilate itself. It is evident that only the forms to which its essential properties make it susceptible can be destroyed and reproduced in turn. Thus, does experience force us to confess that nothing can come from nothing. All philosophers who have not known the light of faith, have thought that this substantial principle of bodies has existed and will exist forever, and that the elements of matter have an indestructible solidity which forbids the fear that the world is going to fall to pieces. The majority of Christian philosophers also recognize that the substantial principle of bodies exists necessarily through itself, and that the power of beginning or ending does not accord with its nature. One finds that this view is upheld by an author of the last century who taught theology in Paris. CHAPTER III. CONCERNING THE EXTENSION OF MATTER. Although we have no idea of the essence of matter, we can not refuse to admit the existence of the properties which our senses discover in it. I open my eyes, and I see around me only matter, or the extended. Extension is then a property which always belongs to all matter, which can belong to matter alone, and which therefore is inseparable from the substance of matter. This property presupposes three dimensions in the substance of bodies, length, width, and depth. Truly, if we consult our knowledge, which is gained entirely from the senses, we cannot conceive of matter, or the substance of bodies, without having the idea of a being which is at the same time long, broad, and deep; because the idea of these three dimensions is necessarily bound up with our idea of every magnitude or quantity. Those philosophers who have meditated most concerning matter do not understand by the extension of this substance, a solid extension composed of distinct parts, capable of resistance. Nothing is united, nothing is divided in this extension; for there must be a force which separates to divide, and another force to unite the divided parts. But in the opinion of these physical philosophers matter has no actually active force, because every force can come only from movement, or from some impulse or tendency toward movement, and they recognize in matter, stripped of all form by abstraction, only a potential moving force. This theory is hard to conceive, but given its principles, it is rigorously true in its consequences. It is one of those algebraic truths which is more readily believed than conceived by the mind. The extension of matter is then but a metaphysical extension, which according to the idea of these very philosophers, presents nothing to affect our senses. They rightly think that only solid extension can make an impression on our senses. It thus seems to us that extension is an attribute which constitutes part of the metaphysical form, but we are far from thinking that extension constitutes its essence. However, before Descartes, some of the ancients made the essence of matter consist in solid extension. But this opinion, of which all the Cartesians have made much, has at all times been victoriously combated by clear reasons, which we will set forth later, for order demands that we first examine to what the properties of extension can be reduced. CHAPTER V. CONCERNING THE MOVING FORCE OF MATTER. The ancients, persuaded that there is no body without a moving force, regarded the substance of bodies as composed of two primitive attributes. It was held that, through one of these attributes, this substance has the capacity for moving and, through the other, the capacity for being moved.{88} As a matter of fact, it is impossible not to conceive these two attributes in every moving body, namely, the thing which moves, and the same thing which is moved. It has just been said that formerly the name, matter, was given to the substance of bodies, in so far as it is susceptible of being moved. When capable of moving this same matter was known by the name of "active principle".... But these two attributes seem to depend so essentially on each other that Cicero, in order better to state this essential and primitive union of matter with its moving principle, says that each is found in the other. This expresses very well the idea of the ancients. From this it is clear that modern writers have given us but an inexact idea of matter in attempting (through a confusion ill understood) to give this name to the substance of bodies. For, once more, matter, or the passive principle of the substance of bodies, constitutes only one part of this substance. Thus it is not surprising that these modern thinkers have not discovered in matter moving force and the faculty of feeling. It should now be evident at the first glance, it seems to me, that if there is an active principle it must have, in the unknown essence of matter, another source than extension. This proves that simple extension fails to give an adequate idea of the complete essence or metaphysical form of the substance of bodies, and that this failure is due solely to the fact that extension excludes the idea of any activity in matter. Therefore, if we demonstrate this moving principle, if we show that matter, far from being as indifferent as it is supposed to be, to movement and to rest, ought to be regarded as an active, as well as a passive substance, what resource can be left to those who have made its essence consist in extension? The two principles of which we have just spoken, extension and moving force, are then but potentialities of the substance of bodies; for in the same way in which this substance is susceptible of movement, without actually being moved, it also has always, even when it is not moving itself, the faculty of spontaneous motion. The ancients have rightly noticed that this moving force acts in the substance of bodies only when the substance is manifested in certain forms; they have also observed that the different motions which it produces are all subject to these different forms or regulated by them. That is why the forms, through which the substance of bodies can not only move, but also move in different ways, were called material forms. Once these early masters had cast their eyes on all the phenomena of nature, they discovered in the substance of bodies, the power of self-movement. In fact, this substance either moves itself, or when it is in motion, the motion is communicated to it by another substance. But can anything be seen in this substance, save the substance itself in action; and if sometimes it seems to receive a motion that it has not, does it receive that motion from any cause other than this same kind of substance, whose parts act the one upon the other? If, then, one infers another agent, I ask what agent, and I demand proofs of its existence. But since no one has the least idea of such an agent, it is not even a logical entity. Therefore it is clear that the ancients must have easily recognized an intrinsic force of motion within the substance of bodies, since in fact it is impossible to prove or conceive any other substance acting upon it. Descartes, a genius made to blaze new paths and to go astray in them, supposed with some other philosophers that God is the only efficient cause of motion, and that every instant He communicates motion to all bodies. But this opinion is but an hypothesis which he tried to adjust to the light of faith; and in so doing he was no longer attempting to speak as a philosopher or to philosophers. Above all he was not addressing those who can be convinced only by the force of evidence. The Christian Scholastics of the last centuries have felt the full force of this reflection; for this reason they have wisely limited themselves to purely philosophic knowledge concerning the motion of matter, although they might have shown that God Himself said that He had "imprinted an active principle in the elements of matter (Gen. i; Is. lxvi)." One might here make up a long list of authorities, and take from the most celebrated professors the substance of the doctrine of all the rest; but it is clear enough, without a medley of citations, that matter contains this moving force which animates it, and which is the immediate cause of all the laws of motion. CHAPTER VI. CONCERNING THE SENSITIVE FACULTY OF MATTER. We have spoken of two essential attributes of matter, upon which depend the greater number of its properties, namely extension and moving force. We have now but to prove a third attribute: I mean the faculty of feeling which the philosophers of all centuries have found in this same substance. I say all philosophers, although I am not ignorant of all the efforts which the Cartesians have made, in vain, to rob matter of this faculty. But in order to avoid insurmountable difficulties, they have flung themselves into a labyrinth from which they have thought to escape by this absurd system "that animals are pure machines."{89} An opinion so absurd has never gained admittance among philosophers, except as the play of wit or as a philosophical pastime. For this reason we shall not stop to refute it. Experience gives us no less proof of the faculty of feeling in animals than of feeling in men.... There comes up another difficulty which more nearly concerns our vanity: namely, the impossibility of our conceiving this property as a dependence or attribute of matter. Let it not be forgotten that this substance reveals to us only ineffable characters. Do we understand better how extension is derived from its essence, how it can be moved by a primitive force whose action is exerted without contact, and a thousand other miracles so hidden from the gaze of the most penetrating eyes, that (to paraphrase the idea of an illustrious modern writer) they reveal only the curtain which conceals them? But might not one suppose as some have supposed, that the feeling which is observed in animated bodies, might belong to a being distinct from the matter of these bodies, to a substance of a different nature united to them? Does the light of reason allow us in good faith to admit such conjectures? We know in bodies only matter, and we observe the faculty of feeling only in bodies: on what foundation then can we erect an ideal being, disowned by all our knowledge? However, we must admit, with the same frankness, that we are ignorant whether matter has in itself the faculty of feeling, or only the power of acquiring it by those modifications or forms to which matter is susceptible; for it is true that this faculty of feeling appears only in organic bodies. This is then another new faculty which might exist only potentially in matter, like all the others which have been mentioned; and this was the hypothesis of the ancients, whose philosophy, full of insight and penetration, deserves to be raised above the ruins of the philosophy of the moderns. It is in vain that the latter disdain the sources too remote from them. Ancient philosophy will always hold its own among those who are worthy to judge it, because it forms (at least in relation to the subject of which I am treating) a system that is solid and well articulated like the body, whereas all these scattered members of modern philosophy form no system. APPENDIX. OUTLINES AND NOTES. BY GERTRUDE CARMAN BUSSEY. LA METTRIE'S RELATION TO HIS PREDECESSORS AND TO HIS SUCCESSORS. I. The Historical Relation of La Mettrie to René Descartes (1596-1650). The most direct source of La Mettrie's work, if the physiological aspect of his system is set aside, is found in the philosophy of Descartes. In fact it sometimes seems as if La Mettrie's materialism grew out of his insistence on the contradictory character of the dualistic system of Descartes. He criticises Descartes's statement that the body and soul are absolutely independent, and takes great pains to show the dependence of the soul on the body. Yet though La Mettrie's system may be opposed to that of Descartes [17] from one point of view, from another point of view it seems to be a direct consequence of it. La Mettrie himself recognizes this relationship and feels that his doctrine that man is a machine, is a natural inference from Descartes's teaching that animals are mere machines. [18] Moreover La Mettrie carries on Descartes's conception of the body as a machine, and many of his detailed discussions of the machinery of the body seem to have been drawn from Descartes. It should be noted that La Mettrie did justice to Descartes, and realized how much all philosophers owed to him. He insisted moreover that Descartes's errors were due to his failure to follow his own method. [19] Yet La Mettrie's method was different from that of Descartes, for La Mettrie was an empiricist [20] without rationalistic leaning. As regards doctrine: La Mettrie differed from Descartes in his opinion of matter. Since he disbelieved in any spiritual reality, he gave matter the attributes of motion and thought, while Descartes insisted that the one attribute of matter is extension. [21] It was a natural consequence of La Mettrie's disbelief in spiritual substance that he could throw doubt on the existence of God. [22] On the other hand the belief in God was one of the foundations of Descartes's system. La Mettrie tried to show that Descartes's belief in a soul and in God was merely designed to hide his true thought from the priests, and to save himself from persecution. [23] IIa. The Likeness of La Mettrie to the English Materialists, Thomas Hobbes (1588-1679) and John Toland (1670-1721). The influence of Descartes upon La Mettrie cannot be questioned but it is more difficult to estimate the influence upon him of materialistic philosophers. Hobbes published "The Leviathan" in 1651 and "De Corpore" in 1655. Thus he wrote about a century before La Mettrie, and since the eighteenth century was one in which the influence of England upon France was very great, it is easy to suppose that La Mettrie had read Hobbes. If so, he must have gained many ideas from him. The extent of this influence is, however, unknown, for La Mettrie rarely if ever quotes from Hobbes, or attributes any of his doctrines to Hobbes. In the first place, both Hobbes and La Mettrie are thoroughgoing materialists. They both believe that body is the only reality, and that anything spiritual is unimaginable. [24] Furthermore their conceptions of matter are very similar. According to La Mettrie, matter contains the faculty of sensation and the power of motion as well as the quality of extension. [25] This same conception of matter is held by Hobbes, for he specifically attributes extension and motion to matter, and then reduces sensation to a kind of internal motion. [26] Thus sensation also may be an attribute of matter. Moreover Hobbes and La Mettrie are in agreement on many smaller points, and La Mettrie elaborates much that is suggested in Hobbes. They both believe that the passions are dependent on bodily conditions. [27] They agree in the belief that all the differences in men are due to differences in the constitution and organization of their bodies. [28] They both discuss the nature and importance of language. [29] Hobbes differs from La Mettrie in holding that we can be sure that God exists as the cause of this world. [30] However even though he thinks that it is possible to know that God exists, he does not believe that we can know his nature. La Mettrie's system may be regarded as the application of a system like that of Hobbes to the special problem of the relation of soul and body in man; for if there is nothing in the universe but matter and motion, it inevitably follows that man is merely a very complicated machine. There is great similarity also between the doctrine of La Mettrie and that of Toland. It is interesting to note the points of resemblance and of difference. Toland's "Letters to Serena," which contain much of his philosophical teaching, were published in 1704. There is a possibility therefore that La Mettrie read them and gained some suggestions from them. The point most emphasized in Toland's teaching [31] is that motion is an attribute of matter. He argues for this belief on the ground that matter must be essentially active in order to undergo change, [32] and that the conception of the inertness of matter is based on the conception of absolute rest, and that this absolute rest is nowhere to be found. [33] Since motion is essential to matter, there is no need, Toland believes, to account for the beginning of motion. Those who have regarded matter as inert have had to find some efficient cause for motion, and to do this, they have held that all nature is animated. But this pretended animation is utterly useless, since matter is itself endowed with motion. [34] The likeness to La Mettrie is evident. La Mettrie likewise opposes the doctrine of the animation of matter, and the belief in any external cause of motion. [35] Yet he feels the need of postulating some beginning of motion, [36] and although he uses the conception so freely, he does not agree with Toland that the nature of motion is known. He believes that it is impossible to know the nature of motion, [37] while Toland believes that the nature of motion is self-evident. [38] Another point of contrast between Toland and La Mettrie is in their doctrines of God. Toland believes that God, "a pure spirit or immaterial being," is necessary for his system, [39] while La Mettrie questions God's existence and insists that immateriality and spirituality are fine words that no one understands. It must be admitted, in truth, that La Mettrie and Toland have different interests and different points of view. Toland is concerned to discover the essential nature of matter, while La Mettrie's problem is to find the specific relation of body and mind. On this relation, he builds his whole system. b. The Relation of La Mettrie to an English Sensationalist: John Locke (1632-1704). Locke's "Essay Concerning Human Understanding" was published in 1690, and La Mettrie, like most cultured Frenchmen of the Enlightenment, was influenced by his teaching. The main agreement between Locke and La Mettrie is in their doctrine that all ideas are derived from sensation. Both vigorously oppose the belief in innate ideas, [40] teaching that even our most complex and our most abstract ideas are gained through sensation. But La Mettrie does not follow Locke in analyzing these ideas and in concluding that many sensible qualities of objects--such as colors, sounds, etc.--have no existence outside the mind. [41] He rejects Locke's doctrine of spiritual substances, [42] and opposes Locke's theistic teaching, laying stress, on the other hand, upon Locke's admission of the possibility that "thinking being may also be material." [43] IIIa. The Likeness, probable but unacknowledged, to La Mettrie, of the French Sensationalists, Etienne Bonnot de Condillac (1715-1780) and Claude Adrien Helvetius (1715-1771). Condillac's "Traité des sensations" was published about ten years after La Mettrie's "L'histoire naturelle de l'âme," and therefore it is probable that Condillac had read this work, and gained some ideas from it. Yet Condillac never mentions La Mettrie's name nor cites his doctrines. This omission may be accounted for by the fact that the works of La Mettrie had been so condemned that later philosophers wished to conceal the similarity of their doctrines to his. Whether the sensationalists were influenced by his teachings or not, there is such a profound likeness in their teachings, that La Mettrie may well be regarded as one of the first French sensationalists as well as one of the leading French materialists of the time. Condillac and La Mettrie agree that experience is the source of all knowledge. As Lange suggests, [44] La Mettrie's development of reason from the imagination may have suggested to Condillac the way to develop all the faculties from the soul. La Mettrie asserts that reason is but the sensitive soul contemplating its ideas, and that imagination plays all the rôles of the soul, while Condillac elaborates the same idea, and shows in great detail how all the faculties of the soul are but modifications of sensation. [45] Both La Mettrie and Condillac believe that there is no gulf between man and the lower animals; but this leads to a point of disagreement between the two philosophers, for Condillac absolutely denies that animals can be mere machines, [46] and we must suppose that he would the more ardently oppose the teaching that man is merely a complicated machine! Condillac finally, unlike La Mettrie, believes in the existence of God. A final point of contrast also concerns the theology of the two writers. La Mettrie insists that we can not be sure that there is any purpose in the world, while Condillac affirms that we can discern intelligence and design throughout the universe. [47] Like La Mettrie and Condillac, Helvetius teaches that all the faculties of the mind can be reduced to sensation. [48] Unlike La Mettrie, he specifically distinguishes the mind from the soul, and describes the mind as a later developed product of the soul or faculty of sensation. [49] This idea may have been suggested by La Mettrie's statement that reason is a modification of sensation. Helvetius, however, unlike La Mettrie, does not clearly decide that sensation is but a result of bodily conditions, and he admits that sensation may be a modification of a spiritual substance. [50] Moreover, he claims that climate and food have no effect on the mind, and that the superiority of the understanding is not dependent on the strength of the body and its organs. [51] La Mettrie and Helvetius resemble each other in ethical doctrine. Both make pleasure and pain the ruling motives of man's conduct. They claim that all the emotions are merely modifications of corporeal pleasure and pain, and that therefore the only principle of action in man is the desire for pleasure and the fear of pain. [52] b. The Likeness to La Mettrie of the French Materialist, Baron Paul Heinrich Dietrich von Holbach (1723-1789). As Condillac and Helvetius emphasize the sensationalism taught by La Mettrie, so Holbach's book is a reiteration and elaboration of the materialism set forth in La Mettrie's works. The teaching of Holbach is so like that of La Mettrie, that the similarity can hardly be a coincidence. La Mettrie regards experience as the only teacher. Holbach dwells on this same idea, and insists that experience is our only source of knowledge in all matters. [53] Holbach likewise teaches that man is a purely material being. He disbelieves in any spiritual reality whatsoever, and makes matter the only substance in the world. He lays stress, also, on one thought which is a natural consequence of La Mettrie's teaching. La Mettrie has limited the action of the will and has insisted that the will is dependent on bodily conditions. Holbach goes further and declares repeatedly that all freedom is a delusion, and that man is controlled in every action by rigid necessity. [54] This teaching seems to be the natural outcome of the belief that man is a machine. Holbach's atheistic theology is more extreme than his predecessor's, for La Mettrie admits that God may exist, while Holbach vigorously opposes the possibility. Moreover Holbach holds the opinion, barely suggested by La Mettrie, that an atheistic doctrine would ameliorate the condition of mankind. [55] He insists that the idea of God has hindered the progress of reason and interfered with natural law. Holbach is indeed the only one of the philosophers here discussed, who frankly adopts a fatalistic and atheistic doctrine of the universe. In these respects, his teaching is the culmination of French materialism. OUTLINE OF LA METTRIE'S METAPHYSICAL DOCTRINE. PAGES [56] I. Insistence on the Empirical Standpoint 16f.; 88f.; 72, 142 II. Arguments in Favor of Materialism: a. The "Soul" is Affected, 1. By Disease 18f.; 90f. 2. By Sleep 19f.; 91f. 3. By Drugs 20; 92 4. By Food 21f.; 93ff. 5. By Age and Sex 23f.; 95f. 6. By Temperature and Climate 24f.; 96ff. b. There is No Sharp Distinction Between Men and Animals (Machines) 28f., 100ff.; 41ff., 113ff.; 75f., 142f. c. Bodily Movements are Due to the "Motive Power" of the Body 51ff., 129ff. III. Conception of Matter. a. Matter is Extended 154f. b. Matter Has the Power of Motion 70, 140; 156ff. c. Matter Has the Faculty of Feeling 159ff. IV. Conception of Man: a. Man is a Machine 17, 89; 21, 93; 56, 128; 69, 140f.; 73, 143; 80, 148 b. All Man's Faculties Reduce to Sense and Imagination 35ff., 107ff. c. Man is Like Animals in Being Capable of Education 38, 110 d. Man is Ignorant of His Destiny 79, 147 V. Theological Doctrine: a. The Existence of God is Unproved and Practically Unimportant 50, 122 b. The Argument from Design is Ineffective Against the Hypothesis of Mechanical Causality 51ff., 124ff. c. Atheism Makes for Happiness 55, 126f. NOTES. [57] NOTE ON FREDERICK THE GREAT'S EULOGY. This translation is made from the third volume, pp. 159 ff. of "OEuvres de Fréderic II., Roi de Prusse, Publiées du vivant de l'Auteur," Berlin, 1789. La Mettrie was received at the court of Frederick the Great, when he had been driven from Holland on account of the heretical teaching of "L'Homme Machine," The "Eloge" was read by Darget, the secretary of the king, at a public meeting of the Academy of Berlin, to which, at the initiative of Frederick, La Mettrie had been admitted. The careful reader will not fail to note that Frederick's arithmetic is at fault, and that La Mettrie died at the age of forty-one, not forty-three, years. At a few points, perhaps, the Eloge demands elucidation. Coutances, like Caen, is a Norman town. St. Malo lies, just over the border, in Brittany. La Mettrie's military service was with the French in the Silesian wars against Maria Theresa. The battle of Dettingen was fought in Bavaria and was won by the Austrians through the aid given by George II of England to Maria Theresa. The battle of Fontenoy in the Netherlands was the only victory of the French in this war. Other accounts of the life of La Mettrie are: J. Assézat, Introduction to "L'Homme Machine," Paris, 1865. F. A. Lange, "History of Materialism." Ph. Damiron, "Histoire de la philosophie du dix-huitième siècle," Paris, 1858. N. Quépat, "La philosophie matérialiste au XVIIIe siècle. Essai sur La Mettrie, sa vie, et ses oeuvres." Paris, 1873. NOTES ON MAN A MACHINE. 1. "Matter may well be endowed with the faculty of thought." Although La Mettrie attempts to "avoid this reef," by refraining from the use of these words, yet he asserts throughout his work that sensations, consciousness, and the soul itself are modifications of matter and motion. The possibility of matter being endowed with the faculty of thought, is denied by Elie Luzac, the publisher of "L'homme machine," in his work "L'homme plus que machine." In this work he tries to disprove the conclusions of "L'homme machine." He says: "We have therefore proved by the idea of the inert state of matter, by that of motion, by that of relations, by that of activity, by that of extension, that matter can not be possessed of the faculty of thinking".... "To be brief, I say, that if, by a material substance, we understand that matter which falls under the cognizance of our senses, and which is endowed with the qualities we have mentioned, the soul can not be material: so that it must be immaterial, and, for the same reason, God could not have given the faculty of thinking to matter, since He can not perform contradictions." [58] 2. "How can we define a being whose nature is absolutely unknown to us?" La Mettrie uses this as an argument against the belief in a soul, and yet he later admits that the "nature of motion is as unknown to us as the nature of matter." It is difficult then to see why there is more reason to doubt the existence of spirit, than to doubt the existence of matter. Locke makes this point very well. "It is for want of reflection that we are apt to think that our senses show us nothing but material things. Every act of sensation, when duly considered, gives us an equal view of both parts of nature, the corporeal and spiritual." [59]... "If this notion of immaterial spirit may have, perhaps, some difficulties in it not easy to be explained, we have therefore no more reason to deny or doubt the existence of such spirits, than we have to deny or doubt the existence of body because the notion of body is cumbered with some difficulties, very hard and perhaps impossible to be explained or understood by us." [60] 3. "Author of the 'Spectacle de la nature.'" Noel Antoine Pluche (1688-1761) was a Jansenist author. He was Director of the College of Laon, but was deprived of his position on account of his refusal to adhere to the bull "Unigenitus." Rollin then recommended him to Gasville, intendant of Normandy, who entrusted him with his son's education. He finally settled in Paris. His principal works are: "Spectacle de la nature," (Paris, 1739); "Mécanique des langues et l'art de les enseigner," (Paris, 1751); "Harmonie des Psaumes et de l'Evangile," (Paris, 1764); "Concorde de la géographie des différents ages," (Paris, 1765). [61] La Mettrie describes Pluche in the "Essais sur l'esprit et les beaux esprits" thus: "Without wit, without taste, he is Rollin's pedant. A superficial man, he had need of the work of M. Réaumur, of whom he is only a stale and tiresome imitator in the flat little sayings scattered in his dialogues. It was with the works of Rollin as with the 'Spectacle de la Nature,' one made the fortune of the other: Gaçon praised Person, Person praised Gaçon, and the public praised them both." [62] This quotation from La Mettrie occurs in Assézat's edition of La Mettrie's "L'homme machine," which was published as the second volume of the series "Singularités physiologiques" (1865). Assézat was a French publisher and writer. He was at one time Secretary of the Anthropological Society, and collaborated with other writers in the publication of "La Revue Nationale," "La Revue de Paris," and "La Pensée nouvelle." His notes to "L'Homme Machine" show great knowledge concerning physiological subjects. He intended to publish a complete edition of Diderot's works, but overwork on this undermined his health, so that he was unable to complete it. [63] 4. Torricelli was a physicist and mathematician who lived from 1608 to 1647. He was a disciple of Galileo, and acted as his amanuensis for three months before Galileo's death. He was then nominated as grand-ducal mathematician and professor of mathematics in the Florentine Academy. In 1643, he made his most famous discovery. He found that the height to which a liquid will rise in a closed tube, depends on the specific gravity of the liquid, and concludes from this that the column of liquid is sustained by atmospheric pressure. This discovery did away with the obscure idea of a fuga vacui, and laid bare the principle on which mercurial barometers are constructed. For a long time the mercurial thermometer was called the "Torricellian tube," and the vacuum which the barometer includes is still known as a "Torricellian vacuum." [64] 5. "Only the physicians have a right to speak on this subject." Luzac says: "'Tis true that if the materiality of the soul was proved, the knowledge of her would be an object of natural philosophy, and we might with some appearance of reason reject all arguments to the contrary which are not drawn from that science. But if the soul is not material, the investigation of its nature does not belong to natural philosophy, but to those who search into the nature of its faculties, and are called metaphysicians." [65] 6. "Man is ... a machine." This is the first clear statement of this theory, which as the title of the work indicates, is the central doctrine of this work. Descartes had strongly denied the possibility of conceiving man as a machine. "We may easily conceive a machine to be so constructed that it emits vocables, and even that it emits some correspondent to the action upon it of external objects which cause a change in its organs,... but not that it should emit them variously so as appositely to reply to what is said in its presence, as men of the lowest grade of intellect can do." [66] 7. "Let us then take in our hands the staff of experience." La Mettrie repeatedly emphasizes the belief that knowledge must come from experience. Moreover he confines this experience to sense experience, and concludes "L'histoire naturelle de l'âme" with these words: "No senses, no ideas. The fewer senses there are: the fewer ideas. No sensations experienced, no ideas. These principles are the necessary consequence of all the observations and experiences that constitute the unassailable foundation of this work." This doctrine is opposed to the teaching of Descartes, who insists that "neither our imagination nor our senses can give us assurance of anything unless our understanding intervene." [67] Moreover Descartes believes that the senses are fallacious, and that the ideal method for philosophy is a method corresponding to that of mathematics. [68] Condillac and Holbach agree with La Mettrie's opinion. Thus, Condillac teaches that man is nothing more than what he has become by the use of his senses. [69] And Holbach says: "As soon as we take leave of experience, we fall into the chasm where our imagination leads us astray." [70] 8. "Galen (Galenus) Claudius, 130 to circa 210 A. D. An eminent Greek physician and philosopher. Born at Pergamus, Mysia, he studied both the Platonic and Peripatetic systems of philosophy. Satyrus instructed him in anatomy. He traveled extensively while young to perfect his education. About 165 A. D. he moved to Rome, and became very celebrated as a surgeon and practising physician, attending the family of Marcus Aurelius. He returned to Pergamus, but probably visited Rome three or four times afterwards. He wrote in philosophy, logic, and medicine. Many, probably most, of his works are lost. He was the one medical authority for thirteen centuries, and his services to logic and to philosophy were also great." [71] 9. The author of "L'histoire de l'âme" is La Mettrie himself. 10. Hippocrates is often termed the "father of medicine." He was born in Cos in 460 B. C. He studied medicine under his father, Heraclides, and Herodicus of Selymbria; and philosophy under Gorgias and Democritus. He was the first to separate medicine from religion and from philosophy. He insisted that diseases must be treated by the physician, as if they were governed by purely natural laws. The Greeks had such respect for dead bodies that Hippocrates could not have dissected a human body, and consequently his knowledge of its structure was limited, but he seems to have been an acute and skilful observer of conditions in the living body. He wrote several works on medicine, and in one of them showed the first principles on which the public health must be based. The details of his life are hidden by tradition, but it is certain that he was regarded with great respect and veneration by the Greeks. [72] 11. "The different combinations of these humors...." Compare this with Descartes's statement that the difference in men comes from the difference in the construction and position of the brain, which causes a difference in the action of the animal spirits. [73] 12. "This drug intoxicates, like wine, coffee, etc., each in its own measure, and according to the dose." Descartes also speaks of the effect of wine. "The vapors of wine, entering the blood quickly, go from the heart to the brain, where they are converted into spirits, which being stronger and more abundant than usual are capable of moving the body in several strange fashions." [74] 13. The quotation from Pope is from the "Moral Essays," published 1731 to 1735, Epistle I, 1, 69. 14. Jan Baptista Van Helmont (1578-1644) was a Flemish physician and chemist. He is noted for having demonstrated the necessity of the balance in chemistry, and for having been among the first to use the word "gas." His works were published as "Ortus Medicinae," 1648. [75] 15. The author of "Lettres sur la physiognomie" was Jacques Pernety or Pernetti. He was born at Chazelle-sur-Lyon, was for some years canon at Lyons, and died there in 1777. [76] 16. Boerhaave. See Note 78. 17. Pierre Louis Moreau de Maupertuis (1698-1759) was a French mathematician, astronomer and philosopher. He supported the Newtonian theory against the Cartesians. In 1740 he became president of the Academy of Berlin. He was the head of the expedition which was sent by Louis XV to measure a degree of longitude in Lapland. Voltaire satirized Maupertuis in the "Diatribe du Docteur Akakia." [77] 18. Luzac sums up the preceding facts by saying: "Here are a great many facts, but what is it they prove? only that the faculties of the soul arise, grow, and acquire strength in proportion as the body does; so that these same faculties are weakened in the same proportion as the body is.... But from all these circumstances it does not follow that the faculty of thinking is an attribute of matter, and that all depends on the manner in which our machine is made, that the faculties of the soul arise from a principle of animal life, from an innate heat or force, from an irritability of the finest parts of the body, from a subtil ethereal matter diffused through it, or in a word, from all these things taken together." [78] 19. "The diverse states of the soul are therefore always correlative with those of the body." This view is in diametrical opposition to the teaching of Descartes, who says: "The soul is of a nature wholly independent of the body." [79] Yet Descartes also states that there is an intimate connection between the two. "The Reasonable Soul ... could by no means be educed from the power of matter ... it must be expressly created; and it is not sufficient that it be lodged in the human body, exactly like a pilot in a ship, unless perhaps to move its members, but ... it is necessary for it to be joined and united more closely to the body, in order to have sensations and appetites similar to ours, and thus constitute a real man." [79] Holbach later emphasizes this close connection between body and soul, which is so insisted upon by La Mettrie. "If freed from our prejudices we wish to see our soul, or the moving principle which acts in us, we shall remain convinced that it is part of our body, that it can not be distinguished from the body except by an abstraction, that it is but the body itself considered relatively to some of the functions or faculties to which its nature and particular organization make it susceptible. We shall see that this soul is forced to undergo the same changes as the body, that it grows and develops with the body.... Finally we can not help recognizing that at some periods it shows evident signs of weakness, sickness, and death." [80] 20. "Peyronie (François Gigot de la), a French surgeon, born in Montpellier, the fifteenth of January, 1678, died the twenty-fifth of April, 1747. He was surgeon of the hospital of Saint-Eloi de Montpellier and instructor of anatomy to the Faculty; then, in 1704, served in the army. In 1717 he became reversioner of the position of first surgeon to Louis XV; in 1731, steward of the Queen's palace; in 1735, a doctor of the King; in 1736, first surgeon of the King, and chief of the surgeons of the kingdom. The greatest merit of La Peyronie is for having founded the Academy of Surgery in Paris, and for having gained special protection for surgery and surgeons in France. He wrote little." [81] 21. "Willis, Thomas (1621-1675), English physician, was born at Great Bedwin, Wiltshire, on 27th January, 1621. He studied at Christ Church, Oxford; and when that city was garrisoned for the king he bore arms for the Royalists. He took the degree of bachelor of medicine in 1646, and after the surrender of the garrison applied himself to the practice of his profession. In 1660, shortly after the Restoration, he became Sedleian professor of natural philosophy in place of Dr. Joshua Cross, who was ejected, and the same year he took the degree of doctor of physic.... He was one of the first members of the Royal Society, and was elected an honorary fellow of the Royal College of Physicians in 1664. In 1666, ... he removed to Westminster, on the invitation of Dr. Sheldon, Archbishop of Canterbury.... He died at St. Martin's on 11th November, 1675, and was buried in Westminster Abbey." [82] 22. "Fontenelle, Bernard le Bovier de. Born at Rouen, France, February 11, 1657; died at Paris, January 9, 1757. A French advocate, philosopher, poet, and miscellaneous writer. He was the nephew (through his mother) of Corneille, and was 'one of the last of the Précieux, or rather the inventor of a new combination of literature and gallantry which at first exposed him to not a little satire' (Saintsbury). He wrote 'Poésies pastorales' (1688), 'Dialogues des morts' (1683), 'Entretiens sur la pluralité des mondes' (1686), 'Histoire des oracles' (1687), 'Eloges des académiciens' (delivered 1690-1740)." [83] 23. "In a word, would it be absolutely impossible to teach the ape a language? I do not think so." Compare with this Haeckel's statement of the relation between man's speech and that of apes. "It is of especial interest that the speech of apes seems on physiological comparison to be a stage in the formation of articulate human speech. Among living apes there is an Indian species which is musical; the hylobates syndactylus sings a full octave in perfectly pure harmonious half-tones. No impartial philologist can hesitate any longer to admit that our elaborate rational language has been slowly and gradually developed out of the imperfect speech of our Pliocene simian ancestors." [84] 24. Johann Conrad Amman was born at Schaffhausen, in Switzerland, in 1669. After his graduation at Basle, he practised medicine at Amsterdam. He devoted most of his attention to the instruction of deaf mutes. He taught them by attracting their attention to the motion of his lips, tongue, and larynx, while he was speaking, and by persuading them to imitate these motions. In this way, they finally learned to articulate syllables and words, and to talk. In his works "Surdus Loquens," and "Dissertatio de Loquela," he explained the mechanism of speech, and made public his method of instruction. From all accounts it seems that his success with the deaf mutes was remarkable. He died about 1730. [85] 25. "... the great analogy between ape and man...." Compare Haeckel: "Thus comparative anatomy proves to the satisfaction of every unprejudiced and critical student the significant fact that the body of man and that of the anthropoid ape are not only peculiarly similar, but they are practically one and the same in every important respect." [86] 26. Sir William Temple was born in London in 1628. He attended the Puritan College of Emmanuel, Cambridge, but left without taking his degree. After an extensive tour on the continent, he settled in Ireland in 1655. His political career began with the accession of Charles II in 1660. He is particularly noted for concluding "The Triple Alliance" between England, the United Netherlands, and Sweden, and for his part in bringing about the marriage of William and Mary, which completed the alliance of England and the Netherlands. Temple was not as successful in political work at home as abroad, for he was too honest to care to be concerned in the intrigues in English affairs, at that time. He retired from politics and died at Moor Park in 1699. Temple wrote several works on political subjects. His "Memoirs" were begun in 1682; the first part was destroyed before it was published, the second part was published without his consent, and the third part was published by Swift after Temple's death. His fame rests more on his diplomatic work than on his writings. [87] 27. "Trembley (Abraham) a Swiss naturalist, born in Geneva, the third of September, 1700, died in Geneva, the twelfth of May, 1784. He was educated in his native city, and in the Hague, where he became tutor of the son of an English resident, and later the tutor of the young duke of Richmond, with whom he traveled in Germany and Italy. In 1760, he obtained the position of librarian at Geneva, and gained a seat in the council of the 'Two Hundred.' His admirable works on the fresh-water snake procured for him his election as member of the Royal Society of London, and as correspondent of the Academy of Sciences in Paris. From 1775 to 1782 he published several works on natural religion, and articles on natural history in the 'Philosophical Transactions,' 1742-57. His most important work is 'Mémoires pour servir à l'histoire d'un genre de polype d'eau douce' (Leyden, 1744; Paris, 2 volumes)." [88] 28. "What was man before the invention of words and the knowledge of language? An animal." Compare this with the statement of Hobbes: "The most noble and profitable invention of all others was that of Speech, consisting of names or appellations, and their connexion, ... without which there had been amongst men neither commonwealth, nor society, nor contract, nor peace, no more than amongst lions, bears, and wolves." [89] 29. Fontenelle. See note 22. 30. "All the faculties of the soul can be correctly reduced to pure imagination." Compare with this La Mettrie's statement in "L'histoire naturelle de l'âme": "The more one studies all the intellectual faculties, the more convinced one remains, that they are all included in the faculty of sensation, upon which they all depend so essentially that without it the soul could never perform any of its functions." [90] This resembles Condillac's doctrine of sensation: "Judgment, reflexion, desires, passions, etc., are nothing but sensation itself which is transformed in diverse ways." [91] Helvetius also says: "All the operations of the mind are reducible to sensation." [92] 31. "See to what one is brought by the abuse of language, and by the use of those fine words (spirituality, immateriality, etc.)." Compare Hobbes, "Though men may put together words of contradictory signification, as spirit and incorporeal; yet they can never have the imagination of anything answering to them." [93] 32. "Man's preëminent advantage is his organism." Luzac says: "This no more proves that organization is the chief merit of man, than that the form of a musical instrument constitutes the chief merit of the musician. In proportion to the goodness of the instrument, the musician charms by his art, and the case is the same with the soul. In proportion to the soundness of the body, the soul is in better condition to exert her faculties." [94] 33. "Such is, I think, the generation of intelligence." Luzac argues against this statement thus: "But if thought and all the faculties of the soul depended only on the organization as some pretend, how could the imagination draw a long chain of consequences from the objects it has embraced?" [95] 34. Pyrrhonism is "the doctrine of Pyrrho of Elis which has been transmitted chiefly by his disciple Timon. More generally, radical Scepticism in general." [96] 35. Pierre Bayle was born at Carlat in 1647. Although the child of Protestant parents, he was converted by the Jesuits. After his reconversion to Protestantism, he was driven out of France, and took refuge first in Geneva, and then in Holland. In 1675 he became professor of philosophy at the Protestant College of Sedan, and in 1681 professor of philosophy and history at Rotterdam. In 1693 he was forced to resign from his position on account of his religious views. Bayle was one of the leading French sceptics of the time. He was a Cartesian, but questioned both the certainty of one's own existence, and the knowledge derived from it. He declared that religion is contrary to the human reason, but that this fact does not necessarily destroy faith. He distinguished religion not only from science, but also from morality, and vigorously opposed those who considered a certain religion necessary for morality. He did not openly attack Christianity, yet all that he wrote awakened doubt, and his work exerted an extensive influence for scepticism. His principal work is the "Dictionnaire historique et critique," published 1695-1697, and containing a vast amount of knowledge, expressed in a piquant and popular style. This fact made the book widely read both by scholars and by superficial readers. 36. Arnobius the Elder was born at Sicca Venerea in Numidia, in the latter part of the third century A. D. He was at first an opponent of Christianity, but was afterwards converted, and wrote "Adversus Gentes" as an apology for Christianity. In this work, he tries to answer the complaints made against Christians on the ground that the disasters of the time were due to their impiety; vindicates the divinity of Christ; and discusses the nature of the human soul. He concludes that the soul is not immortal, for he believes that the belief in the immortality of the soul would have a deteriorating influence on morality. For translation of his work compare Vol. XIX of the "Ante-Nicene Christian Library." [97] 37. "There exists no soul or sensitive substance without remorse." Condillac had said: "There is something in animals besides motion. They are not pure machines: they feel." [98] La Mettrie also attributed remorse to animals, but believed that they are none the less machines. Luzac said in comment: "What renders these systems completely ridiculous, is, that the persons who pronounce men machines, give them properties which belie their assertion. If beings are but machines, why do they grant a natural law, an internal sense, a kind of dread? These are ideas which can not be excited by objects which operate on our senses." [99] 38. "Nature has created us solely to be happy." This is a statement of the doctrine, which La Mettrie develops in his principal ethical work "Discours sur le Bonheur." He teaches that happiness rests upon bodily pleasure and pain. In "L'histoire naturelle de l'âme," La Mettrie states that all the passions can be developed from two fundamental passions, of which they are but modifications, love and hatred, or desire and aversion. [100] Like La Mettrie, Helvetius makes corporeal pleasure and pain the ruling motives for man's conduct. Thus he writes: "Pleasure and pain are and always will be the only principles of action in man." [101]... "Remorse is nothing more than a foresight of bodily pain to which some crime has exposed us." [102] He definitely makes happiness the end of human action. "The end of man is self-preservation and the attainment of a happy existence.... Man, to find happiness, should save up his pleasures, and refuse all those which might change into pains.... The passions always have happiness as an object: they are legitimate and natural, and can not be called good or bad except on account of their influence on human beings. To lead men to virtue, we must show them the advantages of virtuous actions." [103] Holbach, finally, goes further than La Mettrie or Helvetius, and makes purely mechanical impulses the motives of man's action. "The passions are ways of being or modifications of the internal organs, attracted or repulsed by objects, and are consequently subject in their own way to the physical laws of attraction and repulsion." [104] 39. "Ixions of Christianity." Ixion, for his treachery, stricken with madness, was cast into Erebus, where he was continually scourged while bound to a fiery wheel, and forced to cry: "Benefactors should be honored." 40. "Who can be sure that the reason for man's existence is not simply the fact that he exists?" Luzac opposes this by saying: "If the reason of man's existence was in man himself, this existence would be a necessary consequence of his own nature; so that his own nature would contain the cause or reason of his existence. Now since his own nature would imply the cause of his existence, it would also imply his existence itself, so that man could no more be considered as non-existent than a circle can be considered without radii or a picture without features or proportions.... If the existence of man was in man himself, he would then be an invariable being." [105] 41. "Fénelon (François de Salignac de la Mothe-Fénelon), born at Château de Fénelon, Dordogne, France, August 6, 1651, died at Cambrai, France, January 7, 1715. A celebrated French prelate, orator, and author. He became preceptor of the sons of the dauphin in 1689, and was appointed archbishop of Cambrai in 1695. His works include 'Les aventures de Télémaque' (1699), 'Dialogues des morts' (1712), 'Traité de l'éducation des filles' (1688), 'Explication des maximes des saints' (1697), etc. His collected works were edited by Leclère (38 vols., 1827-1830)." [106] 42. "Nieuwentyt (Bernard), a Dutch mathematician, born in West-Graftdijk the tenth of August 1654, died at Purmerend the thirtieth of May, 1718. An unrelenting Cartesian, he combated the infinitesimal calculus, and wrote a polemic against Leibnitz, concerning this subject. He wrote a theological dissertation translated into French under the title "L'existence de Dieu démontrée par les merveilles de la nature" (Paris, 1725)." [107] 43. "Abadie, James (Jacques), born at Nay, Basse-Pyrénées, probably in 1654; died at London, September 25, 1725. A noted French Protestant theologian. He went to Berlin about 1680 as minister of the French church there, and thence to England and Ireland; was for a time minister of the French church in the Savoy; and settled in Ireland as dean of Killaloe in 1699. His chief work is the 'Traité de la vérité de la religion chrétienne' (1684), with its continuation 'Traité de la divinité de nôtre Seigneur Jesus-Christ' (1689)." [108] 44. "Derham (William), English theologian and scholar, born in Stoughton, near Worcester, in 1657, died at Upminster in 1735. Pastor of Upminster in the county of Essex, he could peacefully devote himself to his taste for mechanics and natural history. Besides making studies of watch-making, and of fish, birds, and insects, published in part in the Transactions of the Royal Society, he wrote several works on religious philosophy. The most important, which was popular for a long time and was translated into French (1726), has as title 'Physico-Theology, or the Demonstration of the Existence and the Attributes of God, by the Works of His Creation' (1713). He wrote as complement, in 1714, his 'Astro-Theology, or the Demonstration of the Existence and Attributes of God by the Observation of the Heavens.'" [109] 45. Rais, or Cardinal de Retz (1614-1679), was a French politician and author. From his childhood he was intended for the church. He took an active part in the movement against Cardinal Mazarin, and later became cardinal, but lost his popularity, and was imprisoned at Vincennes. After escaping from there he returned to France and settled in Lorraine, where he wrote his 'Mémoires,' which tell of the court life of his time. [110] 46. Marcello Malpighi (1628-1694) was a renowned Italian anatomist and physiologist. He held the position of lecturer on medicine at Bologna in 1656, a few months later became professor at Pisa, was made professor at Bologna in 1660, went from there to Messina, though he later returned to Bologna. In 1691 he became physician to Pope Innocent XII. Malpighi is often known as the founder of microscopic anatomy. He was the first to see the marvelous spectacle of the circulation of the blood on the surface of a frog's lung. He discovered the vesicular structure of the human lung, the structure of the secreting glands, and the mucous character of the lower stratum of the epidermis. He was the first to undertake the finer anatomy of the brain, and he accurately described the distribution of grey matter, and of the fibre tracts in the cord. His works are: "De pulmonibus" (Bologna, 1661), "Epistolae anatomicae narc. Malpighi et Car. Fracassati" (Amsterdam, 1662), "De Viscerum Structura" (London, 1669), "Anatome Plantarum" (London, 1672), "De Structura Glandularum conglobatarum" (London, 1689). [111] 47. Deism is a system of thought which arose in the latter part of the seventeenth century. Its most important representatives in England were Toland, Collins, Chubb, Shaftsbury, and Tindal. They insisted on freedom of thought and speech, and claimed that reason is superior to any authority. They denied the necessity of any supernatural revelation, and were consequently vigorously opposed by the church. Partly because of this opposition by the church, many of them argued against Christianity, and tried to show that an observance of moral laws is the only religion necessary for man. They taught that happiness is man's chief end, and that, since man is a social being, his happiness can best be gained by mutual helpfulness. Although they declared that nature is the work of a perfect being, they had a mechanical conception of the relation of God to the world, and did not, like later theists, find evidence of God's presence in all the works of nature. [112] 48. "Vanini, Lucilio, self-styled Julius Cæsar. Born at Taurisano, kingdom of Naples, about 1585; burned at the stake at Toulouse, France, February 19, 1619. An Italian free thinker, condemned to death as an atheist and magician. He studied at Rome and Padua, became a priest, traveled in Germany and the Netherlands, and began teaching at Lyons, but was obliged to flee to England, where he was arrested. After his release he returned to Lyons, and about 1617 settled at Toulouse. Here he was arrested for his opinions, condemned, and on the same day executed. His chief works are: 'Amphitheatrum aeternae Providentiae' (1615), 'De admirandis naturae reginae deaeque mortalium arcanis' (1616)." [113] 49. Desbarreaux (Jacques Vallée). A French writer, born at Paris in 1602, who died at Chalon-sur-Saône the ninth of May, 1673. He wrote a celebrated sonnet on penitence, but was rather an unbeliever and sceptic than a penitent. Guy Patin, hearing of his death, said: "He infected poor young people by his licence. His conversation was very dangerous and destructive to the public." [114] 50. Boindin (Nicolas), French scholar and author, born the twenty-ninth of May 1676 at Paris, where he died the thirtieth of November 1751. He was in the army for a while, but retired on account of ill health. He then gave himself up to literature, and wrote several plays. In 1706 he was elected Royal censor and associate of the Academy of Inscriptions. His liberty, or, as it was then called, license of mind, shut the doors of the French Academy to him, and would have caused his expulsion from the Academy of Inscriptions if he had not been so old. He died without retracting his opinions. [115] 51. Denis Diderot (1713-1784) was one of the leaders of the intellectual movement of the eighteenth century. He was at first influenced by Shaftsbury, and was enthusiastic in his support of natural religion. In his "Pensées philosophiques" (1746) he tries to show that the discoveries of natural science are the strongest proofs for the existence of God. The wonders of animal life are enough to destroy atheism for ever. Yet, while he opposes atheism, he also opposes vigorously the intolerance and bigotry of the church. He claims that many of the attributes ascribed to God are contrary to the very idea of a just and loving God. Later, Diderot was influenced by La Mettrie and by Holbach, and became an advocate of materialism which he set forth in "Le rêve d'Alembert" and in the passages contributed to the "Système de la nature." Diderot was the editor of the "Encyclopédie." [116] 52. Trembley. See note 27. 53. "Nothing which happens, could have failed to happen." An enunciation of the doctrine so insisted upon by Holbach. "The whole universe ... shows us only an immense and uninterrupted chain of cause and effect." [117]... "Necessity which regulates all the movements of the physical world, controls also those of the moral world." [118] 54. "All these evidences of a creator, repeated thousands ... of times ... are self-evident only to the anti-Pyrrhonians." La Mettrie holds an opinion contrary not only to that of Descartes and Locke, but also to that of Toland, Hobbes, and Condillac. Descartes, for instance, says: "Thus I very clearly see that the certitude and truth of all science depends on the knowledge alone of the true God." [119] Hobbes asserts: "For he that from any effect he seeth come to pass should reason to the next and immediate cause thereof, and from thence to the cause of that cause, ... shall at last come to this, that there must be, as even the heathen philosophers confessed, one first mover, that is a first and an eternal cause of all things, which is that which men mean by the name of God." [120] Toland's words are: "All the jumbling of atoms, all the Chances you can suppose for it, could not bring the Parts of the Universe into their present Order, nor continue them in the same, nor cause the Organization of a Flower or a Fly.... The Infinity of Matter ... excludes ... an extended corporeal God, but not a pure Spirit or immaterial Being." [121] Condillac writes: "A first cause, independent, unique, infinite, eternal, omnipotent, immutable, intelligent, free, and whose providence extends over all things: that is the most perfect notion of God that we can form in this life." [122] Locke declares: "From what has been said it is plain to me we have a more certain knowledge of the existence of a God than of anything our senses have not immediately discovered to us. Nay I presume I may say, that we more certainly know that there is a God, than that there is anything else without us." [123] 55. "Lucretius (Titus Lucretius Carus). Born at Rome, probably about 96 B.C., died October 15, 55 B.C. A celebrated Roman philosophical poet. He was the author of 'De rerum natura,' a didactic and philosophical poem in six books, treating of physics, of psychology, and (briefly) of ethics from the Epicurean point of view. He committed suicide probably in a fit of insanity. According to a popular but doubtless erroneous tradition, his madness was due to a love-philter administered to him by his wife." [124] 56. "Lamy (Bernard) was born in Mans in the year 1640. He studied first in the college of this city. He later went to Paris, and at Saumar studied philosophy under Charles de la Fontenelle, and theology under André Martin and Jean Leporc. He was at length called to teach philosophy in the city of Angers. He wrote a great many books on theological subjects. His philosophical works are: 'L'art de parler' (1675), 'Traité de méchanique, de l'équilibre, des solides et des liqueurs' (1679), 'Traité de la grandeur en général' (1680), 'Entretiens sur les sciences' (1684), 'Eléments de géométrie,' (1685)." [125] 57. "The eye sees only because it is formed and placed as it is." La Mettrie doubts whether there is any purpose in the world. Condillac, on the other hand, teaches that purpose and intelligence are shown forth in the universe. "Can we see the order of the parts of the universe, the subordination among them, and notice how so many different things compose such a permanent whole, and remain convinced that the cause of the universe is a principle without any knowledge of its effects, which without purpose, without intelligence, relates each being to particular ends, subordinated to a general end?" [126] 58. "Non nostrum inter vos tantas componere lites." Vergil, Eclogue III, line 108. 59. "The universe will never be happy unless it is atheistic." Although La Mettrie calls this a "strange opinion" it is clear that he secretly sympathizes with it. Holbach affirms this doctrine very emphatically. "Experience teaches us that sacred opinions were the real source of the evils of human beings. Ignorance of natural causes created gods for them. Imposture made these gods terrible. This idea hindered the progress of reason." [127] "An atheist ... is a man who destroys chimeras harmful to the human race, in order to lead men back to nature, to experience, and to reason, which has no need of recourse to ideal powers, to explain the operations of nature." [128] 60. "The soul is therefore but an empty word." Contrast this with Descartes's statement: "And certainly the idea I have of the human mind ... is incomparably more distinct than the idea of any corporeal object." [129] Compare this doctrine, also, with Holbach's assertion: "Those who have distinguished the soul from the body seem to have only distinguished their brains from themselves. Truly the brain is the common center, where all the nerves spread in all parts of the human body, terminate and join together.... The more experience we have, the more we are convinced that the word 'spirit' has no meaning even to those who have invented it, and can be of no use either in the physical or in the moral world." [130] 61. William Cowper (1666-1709) was an English anatomist. He was drawn into a controversy with Bidloo, the Dutch physician, by publishing under his own name Bidloo's work on the anatomy of human bodies. His principal works are: "Myotamia reformata" (London, 1694) and "Glandularum descriptio" (1702). [131] 62. William Harvey (1578-1657), an English physician and physiologist, is renowned for his discovery of the circulation of the blood. He was educated at Canterbury and Cambridge, and took his doctor's degree at Cambridge in 1602. During his life he held the position of Lumleian lecturer at the College of Physicians, and of physician extraordinary to James I. His principal works are: "Exercitatio de motu cordis et sanguinis" (1628), and "Exercitationes de generatione animalium" (1651). [132] 63. Francis Bacon (1551-1626) was one of the first to revolt against scholasticism and to introduce a new method into science and philosophy. He claimed that to know reality, and consequently to gain new power over reality, man must stop studying conceptions, and study matter itself. Yet he did not himself know how to gain a more accurate knowledge of nature, so that he could not put into practice the method which he himself advocated. His works are full of scholastic conceptions, though many of the implications of his system are materialistic. Lange claims, [133] indeed, that if Bacon had been more consistent and daring, he would have reached strictly materialistic conclusions. The account of the motion of the heart of the dead convict is found in "Sylva Sylvarum." [134] This book, published in 1627, a year after Bacon's death, contains the account of Bacon's experiments, and of his theories in matters of physiology, physics, chemistry, medicine, and psychology. 64. Robert Boyle, one of the greatest natural philosophers of his age, studied at Eton for three years, and then became the private pupil of the rector of Stalbridge. He traveled through France, Switzerland, and Italy, and while at Florence, studied the work of Galileo. He decided to devote his life to scientific work, and in 1645 became a member of a society of scientific men, which later grew into the Royal Society of London. His principal work was the improvement of the air-pump, and by that the discovery of the laws governing the pressure and volume of gases. Boyle was also deeply interested in theology. He gave liberally for the work of spreading Christianity in India and America, and by his will endowed the "Boyle Lectures" to demonstrate the Christian religion against atheists, theists, pagans, Jews, and Mohammedans. [135] 65. Nicolas Sténon was born at Copenhagen, 1631, and died at Schwerin in 1687. He studied at Leyden and Paris, and then settled in Florence, where he became the physician of the grand duke. In 1672 he became professor of anatomy at Florence, but three years later he gave up this position and entered the church. In 1677 he was made Bishop of Heliopolis and went to Hanover, then to Munster, and finally to Schwerin. His principal work is the "Discours sur l'anatomie du cerveau" (Paris, 1669). [136] 66. La Mettrie's account of involuntary movements is much like that of Descartes. Descartes says: "If any one quickly passes his hand before our eyes as if to strike us, we shut our eyes, because the machinery of our body is so composed that the movement of this hand towards our eyes excites another movement in the brain, which controls the animal spirits in the muscles that close the eyelids." [137] 67. "The brain has its muscles for thinking, as the legs have muscles for walking." Neither Condillac nor Helvetius go so far. Helvetius explicitly states that it is an open question whether sensation is due to a material or to a spiritual substance. [138] 68. Giovanni Alfonso Borelli (1608-1670) was the head of the so-called iatro-mathematical sect. He tried to apply mathematics to medicine in the same way in which it had been applied to the physical sciences. He was wise enough to restrict the application of his system to the motion of the muscles, but his followers tried to extend its application and were led into many absurd conjectures. Borelli was at first professor of mathematics at Pisa, and later professor of medicine at Florence. He was connected with the revolt of Messina and was obliged to leave Florence. He retired to Rome, where he was under the protection of Christina, Queen of Sweden, and remained there until his death in 1679. [139] 69. "For one order that the will gives, it bows a hundred times to the yoke." Descartes, on the other hand, teaches that the soul has direct control over its voluntary actions and thoughts, and indirect control over its passions. [140] La Mettrie goes further than to limit the extent of the will, and questions whether it is ever free: "The sensations which affect us decide the soul either to will or not to will, to love or to hate these sensations according to the pleasure or the pain which they cause in us. This state of the soul thus determined by its sensations is called the will." [141] Holbach insists on this point and contends that all freedom is a delusion: "[Man's] birth depends on causes entirely outside of his power; it is without his permission that he enters this system where he has a place; and without his consent that, from the moment of his birth to the day of his death, he is continually modified by causes that influence his machine in spite of his will, modify his being, and alter his conduct. Is not the least reflexion enough to prove that the solids and fluids of which the body is composed, and that the hidden mechanism that he considers independent of external causes, are perpetually under the influence of these causes, and could not act without them? Does he not see that his temperament does not depend on himself, that his passions are the necessary consequences of his temperament, that his will and his actions are determined by these same passions, and by ideas that he has not given to himself?... In a word, everything should convince man that during every moment of his life, he is but a passive instrument in the hands of necessity." [142] 70. The theory of animal spirits, held by Galen and elaborated by Descartes, is that the nerves are hollow tubes containing a volatile liquid, the animal spirits. The animal spirits were supposed to circulate from the periphery to the brain and back again, and to perform by their action all the functions of the nerves. 71. Berkeley uses the fact that the color of objects varies, as one argument for his idealistic conclusion. [143] 72. It is hard to tell what Pythagoras himself taught, but it is certain that he taught the kinship of animals and men, and upon this kinship his rule for the abstinence from flesh was probably based. Among the writings of the later Pythagoreans we find strange rules for diet which are plainly genuine taboos. For example they are commanded "to abstain from beans, not to break bread, not to eat from a whole loaf, not to eat the heart, etc." [144] 73. Plato forbade the use of wine in his ideal republic. [145] 74. "Nature's first care, when the chyle enters the blood, is to excite in it a kind of fever." Thus, warmth is the first necessity for the body. Compare with this, Descartes's statement: "There is a continual warmth in our heart, ... this fire is the bodily principle of all the movements of our members." [146] This is one of the many instances in which La Mettrie's account of the mechanism of the body is similar to that of Descartes. 75. "Stahl (George Ernst), born at Ansbach, Bavaria, October 21, 1660; died at Berlin, May 14, 1734. A noted German chemist, physician of the King of Prussia from 1716. His works include: 'Theoria medica vera' (1707), 'Experimenta et observationes chemicae' (1731), etc." [147] 76. Philip Hecquet (1661-1737) was a celebrated French physician. He studied at Rheims, and in 1688 became the physician of the nuns of Port Royal des Champs. He returned to Paris in 1693 and took his doctor's degree in 1697. He was twice dean of the faculty of Paris. In 1727 he became the physician of the religious Carmelites of the suburb of Saint Jacques, and remained their physician for thirty-two years. [148] 77. The quotation: "All men may not go to Corinth," is translated from Horace, Ep. 1, 19, 36. "Non cuivis homini contigit adire Corinthum." 78. Hermann Boerhaave was born at Voorhout near Leyden, on December 31, 1668. His father, who belonged to the clerical profession, destined his son for the same calling and so gave him a liberal education. At the University of Leyden, he studied under Gronovius, Ryckius and Frigland. At the death of his father, Boerhaave was left without any provision and supported himself by teaching mathematics. Vandenberg, the burgomaster of Leyden, advised him to study medicine, and he decided to devote himself to this profession. In 1693 he received his degree and began to practice medicine. In 1701 he was made "Lecturer on the Institutes of Medicine" at the University of Leyden. Thirteen years later he was appointed Rector of the University, and the same year became Professor of Practical Medicine there. He introduced into the university the system of clinical instruction. Boerhaave's merit was widely recognized, and his fame attracted many medical students from all Europe to the University of Leyden. Among these was La Mettrie whose whole philosophy was profoundly influenced by the teaching of Boerhaave. In 1728 Boerhaave was elected into the Royal Academy of Sciences of Paris, and two years later he was made a member of the Royal Society of London. In 1731 his health compelled him to resign the Rectorship at Leyden. At this time he delivered an oration, "De Honore, Medici Servitute." He died after a long illness on April 23, 1738. The city of Leyden erected a monument to him in the Church of St. Peter, and inscribed on it: "Salutifero Boerhaavii genio Sacrum." Boerhaave was a careful and brilliant student, an inspiring teacher, and a skilful practitioner. There are remarkable accounts of his skill in discovering symptoms, and in diagnosing diseases. His chief works are: "Institutiones Medicae" (Leyden, 1708); "Aphorismi de cognoscendis et curandis Morbis" (Leyden, 1709), "Libellus de Materia Medica et Remediorum Formulis" (Leyden, 1719), "Institutiones et Experimentae Chemicae" (Paris, 1724). [149] 79. Willis. (See Note 21.) 80. Claude Perrault (1613-1688) was a French physician and architect. He received his degree of doctor of medicine at Paris and practised medicine there. In 1673 he became a member of the Royal Academy of Sciences. Although he never abandoned his work in mathematics, in the natural sciences, and in medicine, he is more noted as an architect than as a physician or scientist. He was the architect of one of the colonnades of the Louvre, and of the Observatory. [150] 81. "Matter is self-moved." In "L'histoire naturelle de l'âme" La Mettrie claims that motion is one of the essential properties of matter. See "L'histoire naturelle de l'âme," Chap. V. 82. "The nature of motion is as unknown to us as that of matter." Unlike La Mettrie, Toland holds that it is possible to know the nature of matter, and declares that motion and matter can not be defined, because their nature is self-evident. [151] Holbach, resembling La Mettrie, teaches that it is futile to seek to know the ultimate nature of matter, or the cause for its existence. "Thus if any one shall ask whence matter came, we shall say that it has always existed. If any one ask, whence came movement in matter, we shall answer that for this same reason matter must have moved from eternity, since motion is a necessary consequence of its existence, its essence, and of its primitive properties, such as extent, weight, impenetrability, shape, etc.... The existence of matter is a fact; the existence of motion is another fact." [152] 83. Huyghens (Christian) was born at The Hague, 1629, and died there in 1695. He was a Dutch physicist, mathematician, and astronomer. He is celebrated for the invention of the pendulum clock which could measure the movements of the planets, for the improvement of the telescope, and for the development of the wave-theory of light. His principal work is "Horologium Oscillatorium" (1673). [153] 84. Julien Leroy (1686-1759) was a celebrated French watchmaker. He excelled in the construction of pendulums and of large clocks. Some have attributed the construction of the first horizontal clock to him, but this is doubtful. Among many other inventions and improvements of clocks, he invented the compensating pendulum which bears his name. [154] 85. Jacques de Vaucanson (1709-1782) was a French mechanist. From his childhood he was always interested in mechanical contrivances. In 1738 he presented to the French Academy his remarkable flute player. Soon after, he made a duck which could swim, eat, and digest, and an asp which could hiss and dart on Cleopatra's breast. He later held the position of inspector of the manufacture of silk. In 1748 he was admitted to the Academy of Sciences. His machines were left to the Queen, but she gave them to the Academy, and in the disturbances which followed the pieces were scattered and lost. Vaucanson published: "Mécanisme d'un flûteur automate" (Paris, 1738). [155] 86. "[Descartes] understood animal nature; he was the first to prove completely that animals are pure machines." Contrast this with La Mettrie's former reference in "L'histoire naturelle de l'âme" to "this absurd system 'that animals are pure machines.' Such a laughable opinion," he adds, "has never gained admittance among philosophers.... Experience does not prove the faculty of feeling any less in animals than in men." [156] It is evident that La Mettrie's opposition to this 'absurd system' was based upon his insistence on the similarity of men and animals. In "L'homme machine" he argues from the same premiss, that animals are machines, that men are like animals, and that therefore men also are machines. NOTES ON THE EXTRACTS FROM "L'HISTOIRE NATURELLE DE L'AME." 87. Matter, according to La Mettrie, is endowed with extensity, the power of movement, and the faculty of sensation. As La Mettrie says, this conception was not held by Descartes, who thought that the essential attribute of matter is extension. "The nature of body consists not in weight, hardness, color, and the like but in extension alone--in its being a substance extended in length, breadth and height." [157] Hobbes's conception of matter is very similar to that of La Mettrie. He specifically attributes motion to matter: "Motion and magnitude are the most common accidents of all bodies." [158] He does not name sensation as an attribute of matter, but he reduces sensation to motion. "Sense is some internal motion in the sentient." [159] Since motion is one of the attributes of matter, and since matter is the only reality in the universe, sensation must be attributed to matter. 88. La Mettrie always insists that matter has the power of moving itself, and resents any attempt to show that the motion is due to an outside agent. In this opinion he is in agreement with Toland. Toland says that those who have regarded matter as inert have had to find some efficient cause for motion; and to do this, they have held that all nature is animated. This pretended animation, however, is utterly useless, since matter is itself endowed with motion. 89. "This absurd system ... that animals are pure machines." (See Note 86.) WORKS CONSULTED AND CITED IN THE NOTES. (An asterisk indicates the edition to which reference is made.) JULIEN OFFRAY DE LA METTRIE. 1745 "L'histoire naturelle de l'âme." The Hague. (This work appears as "Traité de l'âme" in La Mettrie's collected works.) 1748 "L'homme machine." Leyden. "L'homme machine par La Mettrie, avec une introduction et des notes." J. Assézat. Paris, 1865. 1751 "OEuvres philosophiques." London (Berlin). 1764 * "OEuvres philosophiques de Monsieur de la Mettrie," Amsterdam. Besides "L'homme machine" and "Traité de l'âme," the "OEuvres philosophiques" contain the following (dates of first publication added in parentheses): "Abrégé des systèmes." "L'homme plante" (1748). "Les animaux plus que machines" (1750). "L'Anti-Sénèque" (1748). "L'art de jouir" (1751). "Système d'Epicure." ELIE LUZAC. 1748 "L'homme plus que machine." London (Leyden). * "Man More than a Machine," translated from the French of Elie Luzac, and printed with the translation of "Man a Machine" for G. Smith, 1750. RENÉ DESCARTES. 1637 "Essais philosophiques," including "Discours de la méthode." * "The Discourse on Method," translated by John Veitch. Open Court Publishing Co., 1903. 1641 "Meditationes de prima philosophia." 1644 "Principia philosophiae." * "The Meditations and Selections from the Principles of Philosophy," translated by John Veitch. Open Court Publishing Co., 1905. 1650 "Les passions de l'âme." * "OEuvres de Descartes," Vol. IV. Edited by Victor Cousin, Paris, 1824. JOHN TOLAND. 1704 * "Letters to Serena." London. Printed for Bernard Lintot. THOMAS HOBBES. 1650 "Human Nature or the Fundamental Elements of Policie." London. 1651 "Leviathan; Or the Matter, Form, and Power of a Commonwealth, Ecclesiastical & Civil." London. 1655 "Elementorum Philosophiae Sectio Prima: De Corpore." London. * English Works edited by Sir William Molesworth, 1839-45. Volume III. Leviathan. Volume IV. Human Nature. JOHN LOCKE. 1690 "An Essay Concerning Human Understanding." London. * Edition of Books II and IV (with omissions) preceded by the English version of Le Clerc's "Eloge historique de feu Mr. Locke," ed. M. W. Calkins. Open Court Publishing Co., 1905. ETIENNE BONNOT DE CONDILLAC. 1754 "Traité des sensations." Paris and London. 1755 "Traité des animaux." Paris and London. * "OEuvres complètes," 23 vols. Edited by Guillaume Arnoux and Mousnier. Paris, 1798. Vol. III. "Traité des sensations." "Traité des animaux." BARON P. H. D. VON HOLBACH. 1770 "Système de la nature," par M. Mirabaud [really Von Holbach]. * Nouvelle edition avec des notes et des corrections par Diderot. Paris, 1821. C. A. HELVETIUS. 1758 "De l'esprit." Paris. * "De l'esprit, or Essays on the mind and its several faculties," translated from the French by William Mulford. London, 1810. 1772 "De l'homme, de ses facultés, et de son éducation." 2 vols. London. * "A Treatise on Man; His Intellectual Faculties and His Education," translated from the French, with notes, by W. Hooper, M. D., 1810. FREDERICK THE GREAT. * "OEuvres de Frederic II., Roi de Prusse, publiées du vivant de l'auteur." Berlin, 1789: "Eloge de Julien Offray de la Mettrie," Vol. III, pp. 159 ff. FRANCIS BACON. * "Sylva Sylvarum, sive Historia Naturalis," transcripta a J. Grutero Lug. Batavor. 1648. F. A. LANGE. * "History of Materialism," translated by Ernest Chester Thomas, Boston, 1877. W. WINDELBAND. * "History of Philosophy," translated by J. H. Tufts, New York, 1898. A. W. BENN. * "History of English Rationalism in the Nineteenth Century." London, 1906. "La Grande Encyclopédie. Inventaire Raisonné des Sciences, des Lettres, et des Arts, par une Société de Savants et de Gens de Lettres." Paris, 1885-1903. "The Encyclopaedia Britannica. A Dictionary of Arts, Sciences, and General Literature." Ninth Edition. "The Century Dictionary and Cyclopedia." New York. "Dictionary of Philosophy and Psychology," edited by J. M. Baldwin. London and New York, 1901. NOTES [1] Il péche evidemment par une pétition de principe. [2] L'histoire des animaux et des hommes prouve l'empire de la semence des pères sur l'esprit et le corps des enfants. [3] L'auteur de l'Histoire naturelle de l'âme etc. [4] L'auteur de l'Hist. de l'âme. [5] Il y a encore aujourd'hui des peuples, qui, faute d'un plus grand nombre de signes, ne peuvent compter que jusqu'à 20. [6] Dans un cercle, ou à table, il lui fallait toujours un rempart de chaises, ou quelqu'un dans son voisinage du côté gauche, pour l'empêcher de voir des abîmes épouvantables dans lesquels il craignait quelquefois de tomber, quelque connaissance qu'il eut de ces illusions. Quel effrayant effet de l'imagination, ou d'une singulière circulation dans un lobe du cerveau! Grand homme d'un côté, il était à moitié fou de l'autre. La folie et la sagesse avaient chacun leur département, ou leur lobe, séparé par la faux. De quel côté tenait-il si fort à Mrs. de Port-Royal? J'ai lu ce fait dans un extrait du traité du vertige de Mr. de la Mettrie. [7] Au moins par les vaisseaux. Est-il sûr qu'il n'y en a point par les nerfs? [8] Haller dans les Transact. Philosoph. [9] Boerhaave, Inst. Med. et tant d'autres. [10] He evidently errs by begging the question. [11] The history of animals and of men proves how the mind and the body of children are dominated by their inheritance from their fathers. [12] The author of "The Natural History of the Soul." [13] The author of "The History of the Soul." [14] There are peoples, even to-day, who, through lack of a greater number of signs, can count only to 20. [15] In a company, or at table, he always required a rampart of chairs or else some one close to him at the left, to prevent his seeing horrible abysses into which (in spite of his understanding these illusions) he sometimes feared that he might fall. What a frightful result of imagination, or of the peculiar circulation in a lobe of the brain! Great man on one side of his nature, on the other he was half-mad. Madness and wisdom, each had its compartment, or its lobe, the two separated by a fissure. Which was the side by which he was so strongly attached to Messieurs of Port Royal? (I have read this in an extract from the treatise on vertigo by M. de la Mettrie.) [16] Haller in the Transact. Philosoph. [17] "L'histoire naturelle de l'âme," chapters XI, VIII. [18] "Man a Machine," p. 142. Cf. La Mettrie's commentary on Descartes's teaching in "Abrégé des systèmes philosophiques," OEuvres, Tome 2. [19] "Abrégé des systèmes, Descartes," p. 6, OEuvres Philosophiques, Tome 2. [20] "Man a Machine," page 89. Cf. "L'histoire naturelle de l'âme" (or "Traité de l'âme"), OEuvres, 1746, p. 229. [21] Descartes, "Principles," Part II, Prop. 4. [22] "Man a Machine," pp. 122-126. [23] Ibid., p. 142. [24] Hobbes, "Leviathan," Part III, Chap. 34; Part I, Chap. XII, Open Court Edition, p. 169. [25] "L'histoire naturelle de l'âme," Chapters III, V, and VI. [26] "Leviathan," Part I, Chap. I. Cf. "Concerning Body," Part IV, Chap. XXV, 2. [27] "Man a Machine," pp. 90-91. [28] "Leviathan," Part I, Chap. VI, Molesworth Ed., p. 40. Cf. "Man a Machine," p. 90. [29] Ibid., Part I, Chap. IV. Cf. "Man a Machine," p. 103. [30] Ibid., Part I, Chap. XII. [31] "Letters to Serena," V, p. 168. [32] Ibid., p. 196. [33] Ibid., p. 203. [34] Ibid., p. 199. [35] "L'histoire naturelle de l'âme," Chap. V, p. 94. [36] "Man a Machine," p. 139. [37] "Man a Machine," p. 140. [38] "Letters to Serena," V, p. 227. [39] Ibid., V, p. 234. [40] John Locke, "Essay Concerning Human Understanding," Book I, Book II, Chap. I. [41] Locke, "Essay," Book II, Chap. 8. [42] Ibid., Book II, Chap. 23. [43] Ibid., Book IV, Chap. 10. For La Mettrie's summary of Locke, cf. his "Abrégé des systèmes," OEuvres, Tome 2. [44] F. A. Lange, "History of Materialism," Vol. II, Chap. II. [45] "Traité des sensations," Part I. [46] "Traité des animaux," Chap. I, p. 454. [47] "Traité des animaux," Chap. VI, p. 577 ff. [48] "Treatise on Man," Sect. II, Chap. I, p. 96. [49] Ibid., Sect. II, Chap. II, p. 108. [50] "Essays on the Mind," Essay II, Chap. I, p. 35. [51] "Treatise on Man," Chap. XII, p. 161. [52] Ibid., Chap. IX, p. 146; Chap. VII, p. 129. [53] "Système de la nature," Vol. I, Chap. I, p. 6. [54] "Système de la nature," Vol. I, Chap. VI, p. 94. [55] Ibid., Vol. II, Chap. XVI, p. 451, and Chap. XXVI, p. 485. Cf. "Man a Machine," pp. 125-126. [56] The references are to pages of this book. [57] Page-references are to the editions cited on pp. 205-207, except references to "Man a Machine" which are to this translation. The translated or original title of a French book is cited according as the editor has made use of translation or of French text. [58] "Man More than a Machine," pp. 10, 12. For statement of the editions to which these Notes make reference, see pp. 205-207. [59] Locke's "Essay Concerning Human Understanding," Book II. Chap. XXIII, § 15. [60] Ibid., § 31. [61] Condensed and translated from La Grande Encyclopédie, Vol. 26. [62] Translated from a note of Assézat in "L'homme machine." [63] Condensed and translated from La Grande Encyclopédie, Vol. 4. [64] Condensed from the Encyclopaedia Britannica, 9th ed., Vol. XXIII. All references are to this edition. [65] "Man More than a Machine," p. 5. [66] "Discourse on Method," Part. V. [67] "Discourse on Method," Part IV. [68] "Meditations," II. [69] "Traité des sensations," Part IV, Chap. IX, § 5. [70] "Système de la nature," Vol. I, Chap. I. [71] Quoted from Baldwin's Dictionary of Philosophy and Psychology, Vol. I. [72] Condensed from the Encyclopaedia Britannica, Vol. XI. [73] "Les passions de l'âme," Part I, Art. XV, and Art. XXXIX. [74] Ibid., Part I, Art. XV. [75] Condensed from the Century Dictionary, Vol. IX. [76] Translated and condensed from La Grande Encyclopédie, Vol. 26. [77] Condensed from the Century Dictionary, Vol. IX. [78] "Man More than a Machine," p. 23. [79] "Discourse on Method," V, last paragraph. [80] "Système de la nature," Vol. I, Chap. VII. [81] Translated from La Grande Encyclopédie, Vol. 26. [82] Quoted from the Encyclopaedia Britannica, Vol. XXIV. [83] Quoted from the Century Dictionary, Vol. IX. [84] E. Haeckel, "The Riddle of the Universe," Chap. III. [85] Condensed from the Encyclopaedia Britannica, Vol. I. [86] "The Riddle of the Universe," Chap. II. [87] Condensed from the Encyclopaedia Britannica, Vol. XXIII. [88] Translated from La Grande Encyclopédie, Vol. 31. [89] "Leviathan," Part I, Chap. IV. [90] "L'histoire naturelle de l'âme," Chap. XIV. p. 199. [91] "Traité des sensations," p. 50. Cf. ibid., Chap. XII (2). [92] "Treatise on Man," Sect. II, Chap. I, p. 4. Cf. "Essays on Mind," Essay I, Chap. I, p. 7. [93] "Leviathan," Part I, Chap. XII. [94] "Man More than a Machine," p. 25. [95] Ibid., p. 26. [96] Quoted from Baldwin's Dictionary of Philosophy, Vol. II. [97] Condensed from the Encyclopaedia Britannica, Vol. II. [98] "Traité des animaux," Chap. I, p. 454. [99] "Man More than a Machine," p. 65. [100] "L'histoire naturelle de l'âme," Chap. X, § XII. [101] "Treatise on Man," Chap. X. [102] Ibid., Chap. VII. [103] "Le vrai sens du système de la nature," Chap. IX. [104] Ibid., Vol. I, Chap. VIII, p. 140. [105] "Man More than a Machine," pp. 71 and 72. [106] Quoted from the Century Dictionary, Vol. IX. [107] Translated from La Grande Encyclopédie, Vol. 24. [108] Quoted from the Century Dictionary, Vol. IX. [109] Translated from La Grande Encyclopédie, Vol. 14. [110] Condensed from the Century Dictionary, Vol. X. [111] Condensed from the Encyclopaedia Britannica, Vol. XV. [112] Cf. A. W. Benn, "History of English Rationalism," Vol. I, Chap. III. [113] Quoted from the Century Dictionary, Vol. X. [114] Translated and condensed from La Grande Encyclopédie, Vol. 14. [115] Translated and condensed from La Grande Encyclopédie, Vol. 7. [116] Condensed from F. A. Lange, "History of Materialism," Vol. II, Chap. I, and from W. Windelband, "History of Philosophy," Part V, Chap. I. [117] "Système de la nature," Vol. I, Chap. I, p. 12. [118] Ibid., Vol. II, Chap. XI. Cf. Vol. I, Chap. VII. [119] "Meditations," III and V. [120] "Leviathan," Part I, Chap. XII. [121] "Letters to Serena," V, p. 235. [122] "Traité des animaux," Chap. VI, p. 585. [123] "Essay Concerning Human Understanding," Book IV, Chap. X. [124] Quoted from the Century Dictionary, Vol. IX. [125] Translated and condensed from the Dictionnaire des Sciences philosophiques, Vol. III, Paris, 1847. [126] "Traité des animaux," Chap. VI. [127] "Système de la nature," Vol. II, Chap. XVI, p. 451. [128] Ibid., Chap. XXVI, p. 485. Cf. Luzac's criticism in "Man More than a Machine," p. 94. [129] "Meditations," IV. [130] "Système de la nature," Vol. I, Chap. VII, pp. 121-122. [131] Condensed and translated from La Grande Encyclopédie, Vol. 13. [132] Condensed from the Century Dictionary, Vol. IX. [133] F. A. Lange, "History of Materialism," Vol. I, Sec. II, Chap. III. [134] "Sylva Sylvarum sive Historia Naturalis Latio Transcripta a J. Gruteo." Lug. Batavos, 1648. Cf. Bk. IV, Experiment 400. [135] Condensed from the Encyclopaedia Britannica, Vol. IV. [136] Translated and condensed from La Grande Encyclopédie, Vol. 30. [137] "Les passions de l'âme," Part I, Art. 13. [138] "Essays on the Mind," Essay I, Chap. I, pp. 4ff. [139] Condensed from the Encyclopaedia Britannica, Vol. IV. [140] "Les passions de l'âme," Part I, Art. 41. [141] "L'histoire naturelle de l'âme," Chap. XII, p. 164. Cf. Chap. XII, p. 167. [142] "Système de la nature," Vol. I, Chap. VI, pp. 89ff. [143] "Dialogues Between Hylas and Philonous," I, Open Court edition; pp. 27, 28, 29. Cf. "Principles of Human Knowledge," par. 10, 15. [144] Quoted from J. Burnet, "Early Greek Philosophy," Chap. II. [145] Republic, III, 403. [146] "Les passions de l'âme," Part I, Art. VIII. [147] Quoted from the Century Dictionary, Vol. X. [148] Translated and condensed from La Grande Encyclopédie, Vol. 19. [149] Condensed from the Encyclopaedia Britannica, Vol. III. [150] Translated and condensed from La Grande Encyclopédie, Vol. 26. [151] "Letters to Serena," V. [152] "Système de la nature," Vol. II, Chap. II, p. 32. [153] Condensed from the Century Dictionary, Vol. IX. [154] Translated and condensed from La Grande Encyclopédie, Vol. 22. [155] Translated and condensed from La Grande Encyclopédie, Vol. 31. [156] "L'histoire naturelle de l'âme," Chap. VI. [157] "Principles of Metaphysics," Part II, Prop. 4. [158] "De Corpore," Part III, Chap. XV. [159] Ibid., Part IV, Chap. XXV, (2). 
34211	----	Transcriber's note: A few typographical errors have been corrected: they are listed at the end of the text. * * * * * [Illustration: THE VISCERA IN POSITION.] * * * * * A TREATISE ON PHYSIOLOGY AND HYGIENE FOR EDUCATIONAL INSTITUTIONS AND GENERAL READERS. _FULLY ILLUSTRATED._ BY JOSEPH C. HUTCHISON, M. D., _President of the New York Pathological Society, Vice-President of the New York Academy of Medicine, Surgeon to the Brooklyn City Hospital, late President of the Medical Society of the State of New York, etc._ * * * * * NEW YORK: CLARK & MAYNARD, PUBLISHERS, 5 BARCLAY STREET. 1872. * * * * * Entered according to Act of Congress, in the year 1870, By CLARK & MAYNARD. In the Office of the Librarian of Congress, at Washington. Stereotyped by LITTLE, RENNIE & CO. 645 and 647 Broadway. * * * * * TO MY WIFE, WHOSE SYMPATHY HAS, FOR MORE THAN TWENTY YEARS, LIGHTENED THE CARES INCIDENT TO _AN ACTIVE PROFESSIONAL LIFE_, THIS HUMBLE VOLUME IS AFFECTIONATELY INSCRIBED. * * * * * {3} PREFACE. ------o------ This work is designed to present the leading facts and principles of human Physiology and Hygiene in clear and concise language, so that pupils in schools and colleges, and readers not familiar with the subjects, may readily comprehend them. Anatomy, or a description of the structure of an organ, is of course necessary to the understanding of its Physiology, or its uses. Enough of the former study has, therefore, been introduced, to enable the pupil to enter intelligently upon the latter. Familiar language, as far as practicable, has been employed, rather than that of a technical character. With a view, however, to supply what might seem to some a deficiency in this regard, a Pronouncing Glossary has been added, which will enable the inquirer to understand the meaning of many scientific terms not in common use. In the preparation of the work the writer has carefully examined all the best material at his command, and freely used it; the special object being to have it abreast of the present knowledge on the subjects treated, as far as such is possible in a work so elementary as this. The discussion of disputed points has been avoided, it being manifestly inappropriate in a work of this kind. Instruction in the rudiments of Physiology in schools does not necessitate the general practice of dissections, or of experiments upon animals. The most important subjects may be illustrated by {4} drawings, such as are contained in this work. Models, especially those constructed by AUZOUX of Paris, dried preparations of the human body, and the organs of the lower animals, may also be used with advantage. The writer desires to acknowledge his indebtedness to R. M. WYCKOFF, M.D., for valuable aid in the preparation of the manuscript for the press; and to R. CRESSON STILES, M.D., a skilful microscopist and physician, for the chapter "On the Use of the Microscope in the Study of Physiology." Mr. AVON C. BURNHAM, the well-known teacher of gymnastics, furnished the drawing of the parlor gymnasium and the directions for its use. _Brooklyn, N. Y., 1870._ * * * * * {5} CONTENTS. CHAPTER I. PAGE THE FRAMEWORK OF THE BODY 15 _The Bones--Their form and composition--The Properties of Bone--The Skeleton--The Joints--The Spinal Column--The Growth of Bone--The Repair of Bone._ CHAPTER II. THE MUSCLES 25 _The Muscles--Flexion and Extension--The Tendons--Contraction--Physical Strength--Necessity for Exercise--Its Effects--Forms of Exercise--Walking--Riding--Gymnastics--Open-air Exercise--Sleep-- Recreation._ CHAPTER III. THE INTEGUMENT, OR SKIN 41 _The Integument--Its Structure--The Nails and Hair--The Complexion--The Sebaceous Glands--The Perspiratory Glands--Perspiration and its uses--Importance of Bathing--Different kinds of Baths--Manner of Bathing--The Benefits of the Sun--Importance of Warm Clothing--Poisonous Cosmetics._ CHAPTER IV. THE CHEMISTRY OF FOOD 53 _The Source of Food--Inorganic Substances--Water--Salt--Lime--Iron-- Organic Substances--Albumen, Fibrin, and Casein--The Fats or Oils--The Sugars, Starch, and Gum--Stimulating Substances--Necessity of a Regulated Diet._ {6} CHAPTER V. FOOD AND DRINK 64 _Necessity for Food--Waste and Repair--Hunger and Thirst--Amount of Food--Renovation of the Body--Mixed Diet--Milk--Eggs--Meat--Cooking --Vegetable Food--Bread--The Potato--Fruits--Purity of Water--Action of Water upon Lead--Coffee, Tea, and Chocolate--Effects of Alcohol._ CHAPTER VI. DIGESTION 80 _The Principal Processes of Nutrition--The General Plan of Digestion-- Mastication--The Teeth--Preservation of the Teeth--Insalivation--The Stomach and the Gastric Juice--The Movements of the Stomach--Gastric Digestion--The Intestines--The Bile and Pancreatic Juice--Intestinal Digestion--Absorption by means of Blood-vessels and Lacteals--The Lymphatic or Absorbent System--The Lymph--Conditions which affect Digestion--The Quality, Quantity, and Temperature of the Food--The Influence of Exercise and Sleep._ CHAPTER VII. THE CIRCULATION 101 _The Blood--Its Plasma and Corpuscles--Coagulation of the Blood--The Uses of the Blood--Transfusion--Change of Color--The Organs of the Circulation--The Heart, Arteries, and Veins--The Cavities and Valves of the Heart--Its Vital Energy--Passage of the Blood through the Heart--The Frequency and Activity of its Movements--The Pulse--The Sphygmograph--The Capillary Blood-vessels--The Rate of the Circulation--Assimilation--Injuries to the Blood-vessels._ CHAPTER VIII. RESPIRATION 123 _The Objects of Respiration--The Lungs--The Air-Passages--The Movements of Respiration--Expiration and Inspiration--The Frequency of Respiration--Capacity of the Lungs--The Air we Breathe--Changes in the Air from Respiration--Changes in the Blood--Interchange of Gases in the Lungs--Comparison between Arterial and {7} Venous Blood--Respiratory Labor--Impurities of the Air--Dust--Carbonic Acid--Effects of Impure Air--Nature's Provision for Purifying the Air--Ventilation--Animal Heat_. CHAPTER IX. THE NERVOUS SYSTEM 148 _Animal and Vegetative Functions--Sensation, Motion, and Volition--The Structure of the Nervous System--The White and Gray Substances--The Brain--Its Convolutions--Cerebellum--The Spinal Cord and its System of Nerves--The Anterior and Posterior Roots--The Sympathetic System of Nerves--The Properties of Nervous Tissue--Excitability of Nervous Tissues--The Functions of the Spinal Nerves and Cord--The Direction of the Fibres of the Cord--Reflex Activity and its Uses--The Functions of the Medulla Oblongata and the Cranial Ganglia--The Reflex Action of the Brain._ CHAPTER X. THE SPECIAL SENSES 177 _The Production of Sensations--Variety of Sensations--General Sensibility--Pain and its Function--Special Sensation, Touch, Taste, Smell, Sight, and Hearing--The Hand, the Organ of Touch--The Sense of Touch--Delicacy of Touch--Sensation of Temperature and Weight--The Tongue the Organ of Taste--The Nerves of Taste--The Sense of Taste, and its Relations with the other Senses--The Influence of Education on the Taste--The Nasal Cavities, or the Organs of Smell--The Olfactory Nerve--The Uses of the Sense of Smell--The Sense of Sight--Light--The Optic Nerve--The Eyeball and its Coverings--The Function of the Iris--The Sclerotic, Choroid, and Retina--The Tears and their Function--The Movements of the Eyeball--The Function of Accommodation--The Sense of Hearing and Sound--The Ear, or the organ of Hearing--The External, Middle, and Internal Ear._ CHAPTER XI. THE VOICE 227 _Voice and Speech--The Larynx, or the Organ of the Voice--The Vocal Cords--The Laryngoscope--The Production of the Voice--The Use of the Tongue--The different Varieties of Voice--The Change of Voice--Its Compass--Purity of Tone--Ventriloquy._ {8} CHAPTER XII. THE USE OF THE MICROSCOPE IN THE STUDY OF PHYSIOLOGY 236 _The Law of Tissues--Necessity of the Microscope--Different kinds of Microscopes--Additional Apparatus--Preliminary Studies--The Study of Human Tissues--Tissues of the Inferior Animals--Incentives to Study._ APPENDIX. POISONS AND THEIR ANTIDOTES 247 GLOSSARY 252 {9} LIST OF ILLUSTRATIONS FIG. PAGE FRONTISPIECE, } VISCERA IN POSITION,} 1. Section of bone, 17 2. Structure of bone, magnified, 17 3. The skeleton, 18 4. Cells of cartilage, 20 5. Elbow-joint, 21 6. Spinal column, 22 7. The muscles, 24 8. Muscular tissue, magnified, 25 9. Biceps muscle of the arm, 26 10. View of knee-joint, 27 11. Appliance for strengthening the muscles, 35 12. Appliance for strengthening the muscles, 35 13. Parlor gymnasium, 36 14. Root and transverse section of hair, magnified, 43 15. Granules of potato starch, 61 16. Section of the trunk, 81 17. Section of a tooth, 82 18. Section of the jaws, 82 19. Section of the jaws--right side, 84 20. Structure of a salivary gland, 87 21. Head of a horse, showing salivary gland, etc. 87 22. Section of chest and abdomen, 90 23. Organs of digestion, 91 24. The lacteals, 97 25. Blood corpuscles, 102 26. Blood corpuscles of man and lower animals, 103 27. Circulation of the blood, 108 {10} 28. Heart and large vessels, 109 29. Section of the heart, 110 30. Form of the pulse, 116 31. Valves of the veins, 117 32. Web of frog's foot, magnified, 119 33. Circulation in a frog's foot, 119 34. Organs of the chest, 124 35. Larynx, trachea, and bronchial tubes, 125 36. Diagram of the structure of the air-cells, 125 37. Section of the lungs, 126 38. Section of mouth and throat, 127 39. Ciliated cells, 128 40. Cerebro-spinal system, 151 41. Upper surface of the cerebrum, 153 42. Vertical section of the brain, 154 43. Base of the brain, 155 44. Brain and spinal cord, 156 45. Sense of touch, 185 46. Section of nasal cavity, 193 47. Front view of the eye, 200 48. Vertical section of eye, 202 49. Diagram for blind point of eye, 207 50. Retinal image, 210 51. Different shapes of the globe of the eye, 212 52. Function of accommodation, 214 53. Diagram of the ear, 218 54. Section of the ear, 221 55. Section of larynx and trachea, 229 56. View of vocal cords by the laryngoscope, 232 57. Different positions of vocal cords, 232 58. Simple microscope, 238 59. Compound microscope, 239 60. Household microscope, 240 61. Popular microscope, 241 {11} INTRODUCTION. ------o------ The Human Body is the abode of an immortal spirit, and is the most complete and perfect specimen of the Creator's handiwork. To examine its structure, to ascertain the uses and modes of action of its various parts, how to protect it from injury, and maintain it in a healthy condition, is the design of this work. The departments of knowledge which are concerned in these investigations, are the science of Human Physiology and the art of Hygiene. PHYSIOLOGY treats of the vital actions and uses of the various parts of living bodies, whether vegetable or animal. Every living thing, therefore, has a Physiology. We have a _Vegetable_ Physiology, which relates to plants; and an _Animal_ Physiology, relating to the animal kingdom. The latter is also divided into _Comparative_ Physiology, which treats of the inferior races of animals, and _Human_ Physiology, which teaches the uses of the various parts of the human body. HYGIENE, or the art of preserving health, is the practical use of Physiology. It teaches us how to cultivate our bodily and mental powers, so as to increase our strength and to fit us for a higher enjoyment of life. It also shows us how to prevent some of the accidents which may befall the body, and to avoid disease. It is proper that we should {12} understand the construction and powers of our bodies; but it is our duty, as rational beings, to know the laws by which health and strength may be maintained and disease warded off. There are various means by which we gain important information respecting the Physiology of man. Plants aid us in understanding the minute structure of the human body, its circulation, and absorption. From inferior animals we learn much in respect to the workings of the different _organs_, as we call those parts of the system which have a particular duty to perform. In one of them, as in the foot of the frog, we can study the circulation of the blood; in another, we can study the action of the brain. By _vivisection_, or the laying bare of some organ of a living animal, we are able to investigate certain vital processes which are too deeply hidden in the human body to be studied directly. This is not necessarily a cruel procedure, as we can, by the use of anæsthetics, so blunt the sensibility of the animal under operation, that he need not suffer while the experiment is being performed. There are other means by which we gather our information. There are occasionally men, who, from some accident, present certain parts, naturally out of view, in exposed positions. In these cases, our knowledge is of much greater value than when obtained from creatures lower in the scale of being than man. We are greatly aided, also, by the use of various instruments of modern invention. Chief among these is the microscope, which is, as we shall learn hereafter, an arrangement and combination of lenses in such a way as greatly to magnify the objects we wish to examine. {13} We have much to say of Life, or vital activity, in the course of our study of Physiology; but the most that we know of it is seen in its results. What Life is, or where its precise position is, we are not able to determine. We discover one thing, however, that all the parts of the body are united together with wonderful sympathy, so that one part cannot be injured and other parts not suffer damage. It is further evident that all organs are not equally important in carrying on the work of Life; for some may temporarily suspend their action, without serious results to the system, while others must never cease from acting. Yet there is nothing superfluous or without aim in our frames, and no part or organ can suffer harm without actual loss to the general bodily health. On this point Science and Holy Writ strictly agree. * * * * * {14} {15} PHYSIOLOGY, AND HYGIENE. CHAPTER I. THE FRAMEWORK OF THE BODY. _The Bones--Their Form and Composition--The Properties of Bone--The Skeleton--The Joints--The Spinal Column--The Growth of Bone--The Repair of Bone._ [Sidenote: 1. The framework of the body? The superstructure? Softness and delicacy of the organs? How protected?] 1. THE BONES.--The framework which sustains the human body is composed of the _Bones_. The superstructure consists of the various organs on which the processes of life depend. These organs are soft and delicately formed, and, if unprotected, would, in most cases, rapidly be destroyed when subjected to violence, however slight. The bones, having great strength and power of resistance, afford the protection required. [Sidenote: 2. The more delicate the organ? Example in relation to the brain? The eye? The lungs? The services performed by the bones?] 2. The more delicate the organ, the more completely does Nature shield it. For example: the brain, which is soft in structure, is enclosed on all sides by a complete box of bone; the eye, though it must be near the surface of the body to command an extensive view, is sheltered from injury within a deep recess of bone; the lungs, requiring freedom of motion as well as protection, are surrounded by a large case of bone and muscle. The bones serve other useful purposes. They give permanence of form to the body, by {16} holding the softer parts in their proper places. They assist in movement, by affording points of attachment to those organs which have power of motion--the muscles. [Sidenote: 3. Their shape and size? Of what composed? Possibility of being separated? Effect of fire? Of dilute acid?] 3. THE FORM AND COMPOSITION OF THE BONES.--Their shape and size vary greatly in different parts of the body, but generally they are arranged in pairs, one bone for each side of the body. They are composed of both mineral and animal substances, united in the proportion of two parts of the former to one of the latter; and we may separate each of these substances from the other for examination. First, if we expose a bone to the action of fire, the animal substance is driven off, or "burned out." We now find that, though the shape of the bone is perfectly retained, what is left is no longer tough, and does not sustain weight as before. Again, we may remove the mineral portion, which is a form of lime, by placing a bone into a dilute acid. The lime will be dissolved out, and the shape of the bone remain as before; but now its firmness has disappeared, and it may be bent without breaking. [Sidenote: 4. Effect of deficiency of ingredient? Usefulness of the lime? Of the animal substance? Effect of their union? Condition, in youth? Old age?] 4. If, for any reason, either of these ingredients is disproportionate in the bone during life, the body is in danger. The lime is useful in giving rigidity of form, while the animal substance insures toughness and elasticity. By their union, we are able to withstand greater shocks and heavier falls than would be possible with either alone. In youth, the period of greatest activity, the animal constituent is in excess: a bone then does not break so readily, but, when broken, unites with great rapidity and strength. On the other hand, the bones of old persons are more easily broken, and in some cases fail to unite. The mineral matter being then in excess, indicates that the period of active exertion is drawing to a close. {17} [Illustration: FIG. 1.--SECTION OF BONE.] [Illustration: FIG. 2. Structure of bone enlarged.] [Sidenote: 5. In what respect admirably fashioned? Its formation? Microscopic examination? The inference? "Line of beauty?"] 5. THE STRUCTURE OF THE BONES.--If we examine one of the long bones, which has been sawn through lengthwise, we observe that it is admirably fashioned for affording lightness as well as strength (Fig. 1). Its exterior is hard and resisting, but it is porous at the broad extremities, while through the central portion there is a cavity or canal which contains an oily substance, called _marrow_. Let us now take a thin section of bone, and examine it under the microscope; we discover that it is pierced by numerous fine tubes (Fig. 2), about which layers of bone-substance are arranged. Accordingly, though a bone be as hard as stone externally, it is by no means as heavy as stone, by reason of its light interior texture. Another element of power is found in the curved outline of the bones. The curved line is said to be "the line of beauty," as it certainly is the line of strength, and is uniformly employed in the bones whose position exposes them to accident. {18} [Illustration: FIG. 3.--THE SKELETON] {19} [Sidenote: 6. Number of bones? Skeleton? The skull? Chest? The trunk? The trunk and skull, how maintained? What of the arms? Legs?] 6. THE SKELETON.--The number of bones in the human body exceeds two hundred. When these are joined together in the proper places, they form what is termed the _Skeleton_ (Fig. 3). It embraces three important cavities. The first, surmounting the frame, is a box of bone, called the _skull;_ below this, is a bony case, or "chest;" and lower down is a bony basin, called the _pelvis_. The two latter compose the trunk. The trunk and skull are maintained in their proper relations by the "spinal column." Branching from the trunk are two sets of limbs: the arms, which are attached to the chest by means of the "collar-bone" and "shoulder-blade;" and the legs, directly joined to the lower part of the trunk. [Sidenote: 7. Design of the cavities? Give the examples.] 7. The cavities of which we have spoken, are designed for the lodgment and protection of the more delicate and perishable parts of the system. Thus, the skull, together with the bones of the face, shelters the brain and the organs of four senses--sight, hearing, smell, and taste. The chest contains the heart, lungs, and great blood-vessels, while the lower part of the trunk sustains the liver, stomach, and other organs. [Sidenote: 8. Joint or articulation? Movable joints, how compacted? The ligaments of the movable joints? What is a sprain? Consequence of a serious sprain?] 8. THE JOINTS.--The point of union of two or more bones forms a joint or _articulation_, the connection being made in various ways according to the kind and amount of motion desired. The movable joints are compacted together by certain strong fibrous bands, called ligaments. These ligaments are of a shining, silvery whiteness, and very unyielding; so much so, that when sudden violence is brought to bear in the vicinity of a joint, the bone to which a ligament is attached may be broken, while the ligament itself remains uninjured. When this connecting material of the joints is strained or lacerated by an {20} accident, a "sprain" is the consequence. An injury of this sort may be, and frequently is, quite as serious as the breaking of a bone. [Illustration: FIG. 4.--CELLS OF CARTILAGE.] [Sidenote: 9. Office of the ligament? What must it have? How accomplished? Describe it. Synovia?] 9. The ligament, then, secures firmness to the joint; it must also have flexibility and smoothness of motion. This is accomplished by a beautiful mechanism the perfection of which is only feebly imitated by the most ingenious contrivance of man. The ends of the bones are covered by a thin layer of _cartilage_, which being smooth and elastic, renders all the movements of the joint very easy. In addition to this, there is an arrangement introduced for "lubricating" the joint, by means of a delicate sac containing fluid. This fluid is constantly supplied in small quantities, but only so fast as it is used up in exercise. In appearance, it is not unlike the white of an egg, and hence its name _synovia_, or egg-like. [Sidenote: 10. What do we observe as regards the composition of a joint? The ligament and cartilage? What varies? Example of the skull? Other examples? The ball-and-socket joint?] 10. Thus, we observe, that two very different substances enter into the composition of a joint. The ligament, very unyielding, affords strength, while the cartilage, elastic and moist, gives ease and smoothness of motion. The amount of motion provided for varies greatly in different joints. In some there is none at all, as in the skull, where one bone is dove-tailed into another by what are termed _sutures_. Others have a hinge-like motion, such as those of the elbow, wrist, ankle, and knee; the most complete of these being the elbow-joint (Fig. 5). Belonging to another class, the {21} ball-and-socket joint, is that at the shoulder, possessing a freedom of motion greater than any other in the body. [Illustration: FIG. 5.--ELBOW JOINT. A, Bone of the arm; B, C, Bones of the fore-arm.] [Sidenote: 11. What is the spinal column? What does it connect and form? Joints of the vertebræ? Amount of motion? Result?] 11. THE SPINAL COLUMN.--The spinal column is often spoken of as the "back-bone," as if it were a single bone, while, in reality, it is composed of a chain of twenty-six small bones, called _vertebræ_. The spinal column is a wonderful piece of mechanism. It not only connects the important cavities of the body, as has already been shown, but, also, itself forms a canal, which contains the spinal cord. The joints of the vertebræ are remarkable for the thick layers of cartilage which separate the adjacent surfaces of bone. The amount of motion between any two of these bones is not great; but these little movements, taken together, admit of very considerable flexibility, in several directions, without endangering the supporting power of the column. {22} [Sidenote: 12. Elasticity of the frame? Protection of the brain from shocks? Tallness of persons? Effects of reclining?] [Illustration: FIG. 6--THE SPINAL COLUMN.] 12. The abundant supply of intervertebral cartilage has another important use, namely, it adds greatly to the elasticity of the frame. It is due, in part, to this elastic material, and in part to the frequent curves of the spine, that the brain and other delicate organs are protected from the shock of sudden falls or jars. During the day, the constant pressure upon these joints, while the body is erect, diminishes the thickness of the cartilages; so that a person is not so tall in the evening as in the morning. The effects of this compression pass away when the body reclines in a horizontal position. [Sidenote: 13. Change in bone? Example--animal and madder. Rapidity of change in color? Waste and repair?] 13. THE GROWTH OF BONE.--Bone, like all the other tissues of the body, is constantly undergoing change, old material being withdrawn, and new particles taking their place. This has been shown conclusively by experiments. If an animal be fed with madder--a red coloring matter--for a day or two, the bones soon become tinged; then, if the madder be discontinued for a few days, the original color returns. If, however, this material be alternately given and withheld, at short intervals, the bone will be marked by a succession of red and white rings. In very young animals, all the bones become colored in a single day; in older ones, a longer time is required. The process of waste and repair, therefore, is constantly taking place in this hard substance, and with astonishing rapidity. {23} 14. THE REPAIR OF BONE.--Nature's provision for uniting broken bones is very complete. At first, blood is poured out around the ends of the bone, as a result of the injury. This is gradually absorbed, and gives place to a watery fluid, which, thickening from day to day, acquires, at the end of two weeks, the consistency of jelly. This begins to harden, by a deposit of new bone-substance, until, at the expiration of five or six weeks, the broken bone may be said to be united. It is, however, still fragile, and must be used carefully a few weeks longer. The process of hardening continues, and months must pass before the union can be said to be complete. QUESTIONS FOR TOPICAL REVIEW. PAGE 1. What useful purposes do the bones serve? 15, 16 2. State what you can of the composition of the bones. 16 3. Of the usefulness of lime in the bones. 16 4. Of the usefulness of animal substance in the bones. 16 5. State what you can of the structure of the bones. 17 6. Of the strength belonging to the bones. 15, 16, 17 7. What is meant by the human skeleton? 19 8. Give a description of its construction. 19 9. What is meant by a joint in the human frame? 19 10. State what you can of the movable joints. 19, 20 11. What office is performed by the ligaments of the joints? 19, 20 12. What by the cartilage at the joints? 20 13. What movable joints are there? 20, 21 14. Describe the construction of the spinal column. 21 15. What properties and powers does the spinal column possess? 21, 22 16. When is a person taller than at other times? 22 17. Give the reason for this. 22 18. What can you state of the growth of bone? 22 19. Describe the process by which a broken bone is repaired. 23 * * * * * {24} [Illustration: FIG. 7.--THE MUSCLES.] {25} CHAPTER II. THE MUSCLES. _The Muscles--Flexion and Extension--The Tendons--Contraction--Physical Strength--Necessity for Exercise--Its Effects--Forms of Exercise--Walking--Riding--Gymnastics--Open-air Exercise--Sleep--Recreation._ [Sidenote: 1. What are the muscles? Their number? The design of most of them? Of a few?] 1. THE MUSCLES.-- The great mass of the body external to the skeleton, is composed of the flesh, or _Muscles_, which largely determines its outline and weight. The muscles are the organs of motion. Their number is about four hundred, and to each of them is assigned a separate and distinct office. They have all been studied, one by one, and a name given to each, by the anatomist. Each is attached to bones which it is designed to move. A few are circular in form, and enclose cavities, the size of which they diminish by contraction. [Illustration: FIG. 8.--MUSCULAR TISSUE. _a_, _b_, Striped muscular fibres: _c_, The same more highly magnified.] [Sidenote: 2. The structure of flesh? Its color, etc.? The composition of the fibres? How marked?] 2. If we examine a piece of flesh, we observe that it is soft, and of a deep red color. Its structure appears to be composed of layers and bundles of small fibres. Let us further examine these fibres under the microscope. We now discover that they are, in turn, made up of still finer fibres, of _fibrillæ_: these are seen in Fig. 8. The fibres are beautifully {26} marked by parallel wavy lines, about ten thousand to an inch, which give the fibre its name of the _striped_ muscular fibre. All of the voluntary muscles present this appearance. [Sidenote: 3. Arrangement of the muscles? Their action? Flexion and extension? Action of the muscles when we stand erect?] 3. FLEXION AND EXTENSION.--The muscles are, for the most part, so arranged in pairs, or corresponding sets, that when motion is produced in one direction by one set, there is, opposite to it, another muscle, or group of muscles, which brings the limb back to its place. When they act alternately, a to-and-fro movement results. When a joint is bent, the motion is called _flexion_; and when it is made straight again, it is called _extension_. When both sets act equally, and at the same moment, no motion is produced, but the body or limb is maintained in a fixed position: this occurs when we stand erect. The muscles which produce extension are more powerful than those opposite to them. [Illustration: FIG. 9.--A, Biceps muscle of the arm: B, C, Its tendons.] [Sidenote: 4. Kinds of muscles? The voluntary? Involuntary? The heart? Give the example. The hand? Arm?] 4. The muscles are also distinguished, on the other hand, as the voluntary and involuntary muscles, according as they are, or are not, under the control of the will. The heart is an example of the involuntary variety. We cannot change its action in the least by an effort of the will. When we sleep, and the will ceases to act, the heart continues to beat without cessation. The voluntary muscles, on the other hand, are such as are used only when we wish or _will_ to use them--as the muscles of the hand or arm (Fig. 9). {27} [Sidenote: 5. What are the tendons or sinews? Their strength? Color? Location? Tendon of Achilles? The fable? Muscles of the leg?] 5. THE TENDONS.--Tendons, or sinews, are the extremities of muscles, and are compactly fastened upon bone. They are very strong, and of a silvery whiteness. They may be felt just beneath the skin, in certain parts of the body, when the muscles are being used, as at the bend of the elbow or knee. The largest tendon of the body is that which is inserted into the heel, called the tendon of Achilles, after the hero of the Grecian poet, the fable relating that it was at this point that he received his death-wound, no other part of his body being vulnerable. The muscles which extend into the leg unite to form a single and very powerful tendon, and enclose a small bone called the knee-pan, which, acting like a pulley, greatly increases their power, and at the same time protects the front of the knee-joint (Fig. 10). [Illustration: FIG. 10.--VIEW OF KNEE-JOINT. A, Thigh bone: B, Knee-pan: C, D, Leg bones.] [Sidenote: 6. Contraction of the muscles? Bending of the arm or finger? Other agencies? Automatic movements? In cold-blooded animals?] 6. MUSCULAR CONTRACTION.--The muscles, when acted upon by the appropriate stimulus, contract, or so change {28} their shape, that their extremities are brought nearer together. The bending of the arm, or of a finger, is effected in this manner, by the will; but the will is not the only means of producing this effect. Electricity, a sharp blow over a muscle, and other stimuli, also cause it. Contraction does not always cease with life. In man, after death from cholera, automatic movements of hands and feet have been observed, lasting not less than an hour. In certain cold-blooded animals, as the turtle, contraction has been known to take place for several days after the head has been cut off. [Sidenote: 7. Contractility? Give the illustration. What was supposed? What is the case?] 7. The property which, in muscle, enables these movements to take place is called _contractility_. If we grasp a muscle while in exercise (for example, the large muscle in the front of the arm), we notice the alternate swelling and decrease of the muscle, as we move the forearm to and fro. It was at one time supposed that the muscle actually increased in volume during contraction. This, however, is not the case; for the muscle, while gaining in thickness, loses in length in the same proportion; and thus, the volume remains the same in action and at rest. [Sidenote: 8. What further in relation to contraction? Weariness of a muscle? Beating of the heart? Standing and walking?] 8. Contraction is not the permanent, or normal, state of a muscle. It cannot long remain contracted, but after a shorter or longer time, it wearies and is obliged to relax. After a short rest, it can then again contract. It is for this reason that the heart can beat all through life, night and day, by having, as we shall hereafter see, a brief interval of rest between successive pulsations. For the same reason, it is more fatiguing to stand for any great length of time in one position, than to be walking the same period. [Sidenote: 9. Muscular power of animals? How tested? Man's power? Horse's? The comparison?] 9. RELATIVE STRENGTH OF ANIMALS.--The amount of muscular power which different animals can exert, has {29} been tested by experiment. By determining the number of pounds which an animal can drag upon a level surface, and afterward comparing that with its own weight, we can judge of its muscular force. It is found that man is able to drag a little less than his own weight. A draught-horse can exert a force equal to about two-thirds of his weight. The horse, therefore, though vastly heavier than man, is relatively not so powerful. [Sidenote: 10. Power of insects? Beetles? Give the conclusion.] 10. Insects are remarkable for their power of carrying objects larger and heavier than themselves. Many of them can drag ten, and even twenty times their weight. Some of the beetles have been known to move bodies more than forty times their own weight. So far, therefore, from it being a fact that animals have strength in proportion to their weight and bulk, the reverse of that statement seems to be the law. [Sidenote: 11. Difference in strength of individuals? How caused?] 11. PHYSICAL STRENGTH.--The difference in strength, as seen in different individuals, is not due to any original difference in their muscles. Nature gives essentially the same kind and amount of muscles to each person, and the power of one, or the weakness of another, arises, in great part, from the manner in which these organs are used or disused. [Sidenote: 12. Complaint in relation to degeneracy? How true? How determined by armor? The fair supposition?] 12. Many authors complain of the physical degeneracy of men at the present day, as compared with past generations. There is room for doubt as to the correctness of this statement. Certain experiments have recently been made with the metallic armor worn seven hundred years ago, by which it is found that any man, of ordinary height and muscular development, can carry the armor and wield the weapons of an age supposed to be greatly our superior in strength. When we consider that in those days, only very strong men could endure the hardships of soldier-life, {30} it is fair to suppose that our age has not so greatly degenerated in respect to physical strength. [Sidenote: 13 Action? Use of organs? Training of the mind? The child's brain? Education of the body?] 13. IMPORTANCE OF EXERCISE.--Action is the law of the living body. Every organ demands use to preserve it in full vigor, and to obtain from it its best services. The value of that training of the mind, which we call education, is everywhere recognized. The child is early put to school, and for many years continues to study, in order that his brain, which is the great centre of mental power, may act healthfully and with force. It is important that the body, also, should receive its education by exercise. This is especially true of persons belonging to certain classes of society, whose occupation confines them within doors, and requires chiefly brain-work. [Sidenote: 14 Work in the open air? A perfect business? The consequence of universal perfect business? Occupation of children?] 14. Persons who are engaged in manual labor in the open air obtain all the exercise necessary for bodily health in their regular business: their need is more likely to be a discipline or exercise of the mind. A perfect business of life, therefore, would be one which would combine both physical and mental labor in their proper proportions. If such a business were possible for all the human race, life would thereby be vastly prolonged. Such is, in fact, to a large extent, the occupation pertaining to one period of life--childhood. A part of the time is spent by the child in improving his mind by study, and another part of the time he has physical exercise in his games and sports. [Sidenote: 15 In what does exercise consist? Effects of it?] 15. THE EFFECTS OF EXERCISE.--Exercise consists in a well-regulated use of the voluntary muscular system. The effects, however, are not limited to the parts used. Other organs, which are not under the control of the will, are indirectly influenced by it. For instance, the heart beats more rapidly, the skin acts more freely, and {31} becomes hotter, as well as the parts beneath it, and the appetite and power of digestion are increased. An increased exhalation from the lungs and skin purifies the current of the circulation, and the body as a whole thrives under its influence. [Sidenote: 16. General effect upon the muscles? Special effect? Effects of inaction? Of excessive exercise?] 16. The immediate effect of exercise, however, is upon the muscles themselves; for by use they become firm and large, and increase in power. If we examine a muscle thus improved by exercise, we find that its fibres have become larger and more closely blended together, that its color is of a darker red, and that the supply of blood-vessels has increased. Without exercise the muscle appears thin, flabby, and pale. On the other hand, excessive exercise, without sufficient relaxation, produces in the muscle a condition not very different from that which follows disuse. The muscle is worn out faster than nature builds it up, and it becomes flabby, pale, and weak. [Sidenote: 17. Of violent and spasmodic efforts? Strength, how attained? Give the particulars.] 17. Violent exercise is not beneficial; and spasmodic efforts to increase the muscular strength are not calculated to secure such a result. Strength is the result of a gradual growth, and is most surely acquired if the exercise be carried to a point short of fatigue, and after an adequate interval of rest. To gain the most beneficial results, the exercise should be at regular hours, and during a regular period. The activity of the exercise, and the time devoted to it must vary, of course, with the strength of the individual, and should be carefully measured by it. [Sidenote: 18. What may walking be called? What further is said of walking?] 18. DIFFERENT MODES OF EXERCISE.--There are very few who have not the power to walk. There is required for it no expensive apparatus, nor does it demand a period of preliminary training. _Walking may be called the universal exercise._ With certain foreign nations, the English {32} especially, it is a very popular exercise, and is practised habitually by almost every class of society; by the wealthy as well as by those who have no carriages; by women as well as by men. [Sidenote: 19. What is said of running, and other like movements? What, as related to childhood? What instances are alluded to? Example?] 19. Running, leaping, and certain other more rapid and violent movements, are the forms of exercise that are most enjoyed in childhood. For the child, they are not too severe, but they may be so prolonged as to become injurious. Instances have been recorded where sudden death has resulted after violent playing, from overtaxing the heart: for example, we have the case of a young girl who, while skipping the rope, and endeavoring to excel her playmates by jumping the greatest number of times, fell dead from rupture of the heart. [Sidenote: 20. Carriage-riding? Horseback-riding?] 20. Carriage-riding, as a means of passive exercise, is particularly well suited to invalids, and persons advanced in life. Horseback exercise brings into use a greater number of muscles than any other one exercise, and with it there is an exhilaration of feeling which refreshes the mind at the same time. It is one of the manliest of exercises, but not less suitable for women than for men. To be skilful in riding, it is best to begin its practice in youth; but there are very few kinds of exercise of which the same is not equally true. [Sidenote: 21. Boating, swimming, and skating?] 21. For those who live near streams or bodies of water, there are the delightful recreations of boating, swimming, and skating. Certain of these exercises have a practical importance aside from and above their use in increasing the physical vigor. This is especially true of boating and swimming, since they are often the means of saving life. Practice in these exercises also teaches self-reliance, courage, and presence of mind. Persons who have become proficient in these vigorous exercises are generally the ones, {33} who, in times of danger, are the quickest to act and the most certain to do so with judgment. [Sidenote: 22. What kind of exercise yields the best results? What advice is given?] 22. PHYSICAL CULTURE.--That form of exercise which interests and excites the mind, will yield the best results; but to some persons no kind of exertion whatever is, at first, agreeable. They should, nevertheless, make a trial of some exercise, in the expectation that, as they become proficient in it, it will become more pleasant. In exercise, as many sets of muscles should be employed as possible, open-air exercise being the best. Parlor gymnastics, and the discipline of the gymnasium are desirable, but they should not be the sole reliance for physical culture. No in-door exercise, however excellent in itself, can fill the place of hearty and vigorous activity in the open air. [Sidenote: 23. Physical culture among the ancients? In Greece? In schools and colleges at the present time? Result to the body and mind?] 23. GYMNASTIC EXERCISES FOR SCHOOLS AND COLLEGES.--In the system of education among the ancients, physical culture predominated. In ancient Greece, physical exercises in schools were prescribed and regulated by law, and hence these schools were called _gymnasia_. At the present time, on the contrary, this culture is almost wholly unknown, as a part of the course of education, in our schools and colleges. In a few of our institutions of learning, however, physical exercises have been introduced, with manifest advantage to the students, and they form a part of the regular curriculum of exercises,--as much so as the recitations in geography, grammar, or Greek. The good effect of the experiments, as shown in improved scholarship as well as increased bodily vigor, in the institutions where the plan has been tried, will, it is hoped, lead to its universal adoption. We should then hear less frequently of parents being obliged to withdraw their children from school, because they become exhausted {34} or, perchance, have lost their health from intense and protracted mental application. [Sidenote: 24. The result of gymnastics in our colleges and other institutions of learning?] 24. Were gymnastics more common in our educational institutions we should not so often witness the sad spectacle of young men and women leaving our colleges and seminaries, with finished educations it may be, but with constitutions so impaired, that the life which should be devoted to the accomplishment of noble purposes must be spent in search of health. Spinal curvatures, which, according to the experience of physicians, are now extremely frequent, especially among ladies, would give place to the steady gait and erect carriage which God designed his human creatures should maintain. 25. All the exercises necessary for the proper development of the body may be obtained from the use of a few simple contrivances that every one can have at home, at little cost--less by far than is spent for useless toys. Many of these may be made available in the parlor or chamber, though all exercises are far more useful in the open air. A small portion of the day thus spent will afford agreeable recreation as well as useful exercise. The Indian club, the wand, the ring, and the dumb-bells answer ordinary purposes very well. Illustrations are here introduced of a few simple contrivances that may be useful for general exercises, and are specially suitable for persons with _weak spines_, or with spines that are the subject of lateral curvature. 26. One of the simplest appliances for strengthening the muscles of the spine, designed chiefly to exercise the muscles on either side of the spine, consists of two wooden handles attached to india-rubber cords, one of which is attached to a hook made fast in the ceiling, or in the top of the door-case; and the other to another hook fastened in the wall, door-post, or window-casing, about the height {35} of the shoulder. When traction is made with the left hand, it exercises the muscles on the left side of the spine, while those on the opposite side are left almost at rest, owing to the oblique direction given to the shoulders when the right hand grasps the horizontal cord. (This appliance will be understood by referring to Fig. 13.) [Illustration: FIG. 11.] [Illustration: FIG. 12.] {36} 27. Fig. 11 shows an appliance consisting of two strong elastic cords, with handles, secured to a hook in the floor, so arranged that the patient has to stoop forward to reach them. On raising the body the spinal muscles are powerfully exercised. Fig. 12 shows other modes of using the elastic cords for strengthening the spine and chest. [Illustration: FIG. 13.] 28. These various appliances have been combined so as to form a system of gymnastics suitable for parlor use; other appliances have been added by which the muscles of {37} the legs may be called into action as well as those of the spine and upper part of the body (Fig. 13). Combinations of cords suitable for particular cases may also be made, and by using one or several cords on the same hook, their power may be adapted to the strength of the most robust as well as to that of the invalid, or of the most delicate child. The entire apparatus is quite simple in its construction and inexpensive, requiring but little space, and at the same time affording a great variety of exercises. EXERCISES THAT MAY BE PRACTISED ON THIS APPARATUS. EXERCISE I. (Fig. 13).--Stand erect under the cords and place the heels together. Grasp the handles firmly, keeping the knees and elbows stiff, and pull downward and forward until the fingers nearly touch the toes. Return slowly to the erect position. Repeat. EXERCISE II. (Fig. 13).--Stand erect, and having grasped the handles overhead firmly, separate them and bring them down slowly until they touch the sides: then return them slowly to the original position. Repeat. EXERCISE III. (Fig. 13).--Stand erect, heels together, grasp the handles overhead, and charge forward with the right foot. Return to first position, and then charge with the left. Repeat, using the right and left foot alternately. EXERCISE IV. (Fig. 13).--Stand erect, heels together. Grasp the handle overhead, and charge forward with the right foot, knee bent. Remain in this position and bring the arms down to the sides so that the arm and fore-arm may form a right angle. Still holding the handles, thrust forward, first the right hand and then the left, until the arm is straight. Repeat. Return to first position, then charge forward with the left foot, performing the same movements as before. EXERCISE V. (Fig. 13).--In this exercise we change to the pulleys leading from the side posts, which can be used in several different ways. 1st. Stand erect, heels together, facing one of the posts, grasp the handle with the right hand, the arm being extended, then flex the fore-arm on the arm. Repeat. Perform the same movements with the left hand. 2d. Stand with back to the post; grasp the pulley behind with the right hand, then gradually bring the hand forward until it is extended in a straight line in front. Repeat. Perform the same exercise with the left hand. {38} EXERCISE VI. (Fig. 13).--This exercise is especially adapted to the legs. Stirrups are so arranged that they can be attached to the pulleys overhead, and can hang down to within three or four feet of the floor. Place the foot in the stirrup, and then press down until it touches the floor. Repeat. Exercise the left foot in the same way. EXERCISE VII. (Fig. 13.)--This exercise requires a little attention in the adjustment of the apparatus. Under the pulleys in the floor are passed ropes which can be attached to the snap-hooks that hold the handles overhead. Stoop forward with the knees stiff, and take hold of the handles, and then raise the body to the erect position. Repeat. EXERCISE VIII. (Fig. 13).--Sit on the floor or on a seat three or four inches high; bend forward, take hold of the handles, and perform the same movements that you would in rowing a boat. EXERCISE IX. (Fig. 13).--The trapeze can now be let down; take hold of it with both hands, sustaining the weight of the body with the arms, then rotate the body first from right to left, then from left to right alternately. This exercise is especially suitable for females. EXERCISE X. (Fig. 13).--Grasp the trapeze as before, bearing all the weight with the arms: then draw the body up slowly until you can place the chin over the bars. This requires strength of muscle, and might strain if done too violently; if slowly performed there is no danger. These are but a few of the exercises that can be practised with this apparatus. As these become familiar they can easily be modified, and new ones can be arranged to meet the requirements of particular cases. Most of the exercises described can be practised with one hand so as to strengthen the muscles on one side. [Sidenote: 29. Need of repose? How do we obtain rest? Alfred the Great? The eight-hour division of time?] 29. REST.--We cannot always be active: repose must succeed labor. We obtain this rest partly by suspending all exertion, as in sleep, and partly by a change of employment. It is said that Alfred the Great recommended that each day should be divided in the following manner: "Eight hours for work, eight hours for recreation, and eight hours for sleep." This division of time is as good as any that could now be made, if it be borne in mind that, when the work is physical, the time of recreation should {39} be devoted to the improvement of the mind; and when mental, we should then recreate by means of physical exercise. [Sidenote: 30. Cessation of voluntary activity? Temperature of the body? Consequence? Body and mind during sleep? Nutrition? Describe it. Consequences of insufficient sleep?] 30. During sleep, all voluntary activity ceases, the rapidity of the circulation and breathing diminishes, and the temperature of the body falls one or two degrees. In consequence, the body needs warmer coverings than during the hours of wakefulness. During sleep, the body seems wholly at rest, and the mind is also inactive, if we except those involuntary mental wanderings which we call dreams. Nevertheless a very active and important physical process is going on. Nutrition, or the nourishing of the tissues, now takes place. While the body is in action, the process of pulling down predominates, but in sleep, that of building up takes place more actively. In this way we are refreshed each night, and prepared for the work and pleasures of another day. If sleep is insufficient, the effects are seen in the lassitude and weakness which follow. Wakefulness is very frequently the forerunner of insanity, especially among those who perform excessive mental labor. [Sidenote: 31. Amount of sleep in different persons? Cases? Frederick the Great? Bonaparte? Instances of long deprivation of sleep?] 31. All persons do not require the same amount of sleep, but the average of men need from seven to nine hours. There are well-authenticated cases where individuals have remained without sleep for many days without apparent injury. Frederick the Great required only five hours of sleep daily. Bonaparte could pass days with only a few hours of rest. But this long continued absence of sleep is attended with danger. After loss of sleep for a long period, in some instances, stupor has come on so profoundly, that there has been no awaking. [Sidenote: 32. Instances of sailors? French soldiers? During torture?] 32. There are instances related of sailors falling asleep {40} on the gun-decks of their ships while in action. On the retreat from Moscow, the French soldiers would fall asleep on the march, and could only be aroused by the cry, "The Cossacks are coming!" Tortured persons are said to have slept upon the rack in the intervals of their torture. In early life, while engaged in a laborious country practice, the writer not unfrequently slept soundly on horseback. These instances, and others, show the imperative demand which nature makes for rest in sleep. QUESTIONS FOR TOPICAL REVIEW. PAGE 1. What can you state of the number and division of the muscles? 25, 26 2. Describe the structure of the muscles. 25, 26 3. Their arrangement in pairs and consequent action. 26 4. What is the difference between the motion called flexion and that called extension? 26 5. Describe their action, and state which are the more powerful. 26 6. What is the difference between voluntary and involuntary muscles? 26 7. Illustrate the difference between the two. 26 8. State all you can of the tendons or sinews. 27 9. What is meant by contraction of the muscles? 27, 28 10. In how many and what ways may contraction be effected? 28 11. What is stated of after-death contraction? 28 12. Why cannot a muscle in life continue contracted a long time? 28 13. How then can the constant beating of the heart be explained? 28 14. How does the strength of a man compare with that of a horse? 29 15. What can you state in relation to the relative strength of animals? 28, 29 16. What, in relation to physical strength? 29 17. What, in relation to physical degeneracy? 29, 30 18. What, in relation to the importance of exercise? 30 19. What is the effect of exercise upon the heart, skin, and appetite? 30, 31 20. How does exercise affect the current of the body's circulation? 31 21. How does judicious exercise affect the muscles? 31 22. What is stated of violent and spasmodic exercise? 31 23. Of the exercise of walking? 31, 32, 33 24. Of running, leaping, and other modes of exercise? 32 25. Of physical culture, in connection with out-door exercises? 33 26. Of the importance of gymnastics in our schools and colleges? 33, 34 27. Of the importance of rest from labor or exercise? 38, 39 28. What processes take place during sleep? 39 29. What effects follow insufficient sleep? 39 * * * * * {41} CHAPTER III. THE INTEGUMENT, OR SKIN. _The Integument--Its Structure--The Nails and Hair--The Complexion--The Sebaceous Glands--The Perspiratory Glands--Perspiration and its Uses--Importance of Bathing--Different kinds of Baths--Manner of Bathing--The Benefits of the Sun--Importance of Warm Clothing--Poisonous Cosmetics._ [Sidenote: 1. What is the skin? Parts directly beneath? What is shown?] 1. THE INTEGUMENT.--The skin is the outer covering of the body. The parts directly beneath it are very sensitive, and require protection. This is shown whenever by accident the skin is broken, pierced, or torn off, the bared surface being very tender, and painful to the touch. Nature has provided the body with a garment that is soft, pliable, close-fitting, and very thin, and yet sufficiently strong to enable us to come in contact with the objects that surround us, without inconvenience or suffering. [Sidenote: 2. Microscopic examination? What is the cutis? The cuticle? Their union? How separated? What further is said of the cuticle?] 2. THE STRUCTURE OF THE SKIN.--When examined with the aid of the microscope, the skin is found to be made up of two layers--the outer and the inner. The inner one is called the _cutis_, or true skin; the outer one is the _epidermis_, or scarf-skin. The latter is also known as the _cuticle_. These two layers are closely united, but they may be separated from each other. This separation takes place whenever, from a burn, or other cause, a blister is formed; a watery fluid is poured out between the two layers, and lifts the epidermis from the true skin. Of the two layers, the cuticle is the thinner in most parts of the body, and has the appearance of a whitish membrane. It is tough and elastic, is without feeling, and does {42} not bleed, when cut. Examine it more closely, and we observe that it is composed of minute flat cells, closely compacted, and arranged layer upon layer. [Sidenote: 3. Wearing out of the cuticle? What then? Variety in thickness of cuticle? How accounted for?] 3. The outer layer is constantly being worn out, and falls from the body in the form of very fine scales. It is, also, continually forming anew on the surface of the inner layer. Its thickness varies in different parts of the body. Where exposed to use, it is thick, hard, and horn-like, as may be seen on the soles of the feet, or on the palms of the hands, especially of those who are accustomed to perform much manual labor. This is an admirable provision for the increased protection of the sensitive parts below the skin against all extraordinary exposure. Even the _liabilities_ of these parts to injury, are thus kindly provided for by "the Hand that made us." [Sidenote: 4. Location and office of the cutis? What further is said of it? Papillæ? Touch?] 4. The cutis, or true skin, lies beneath the epidermis, and is its origin and support. It is firm, dense, elastic, very sensitive, and is freely supplied with blood-vessels. It is closely connected with the tissues below it, but may be separated by means of a sharp instrument. The surface of the cutis is not smooth, but is covered here and there with minute elevations, called _papillæ_. These are arranged in rows, along fine lines, or ridges, such as those which mark the palm and fingers; their number is about 80 to the square line (a line being one-twelfth of an inch). These _papillæ_ contain the blood-vessels which carry the supply of blood needed by the ever-wasting skin. They contain nerves also, and are largely concerned in the sense of touch; hence they are particularly abundant where the touch is most delicate, as at the ends of the fingers. [Sidenote: 5. What are the nails and hair? The growth of the nail? The rapidity of its growth? Accident to the nail?] {43} [Illustration: Fig. 14. _a, b._ THE ROOT OF A HAIR. 1, 2, 3. The skin forming the hair sac. 4. Sebaceous glands. 5. The hair sac. _c._ TRANSVERSE SECTION OF A HAIR.] 5. THE NAILS AND HAIR.--These are appendages of the skin, and although very unlike the cuticle as it appears on the surface of the body, they are, in reality, modified forms of that layer of the skin. The nail grows from a fold of the cuticle at the root, and from the under surface. As fast as it is formed, it is constantly being pushed outward. The rapidity of its growth can be ascertained by filing a slight groove on its surface, and noticing how the space between it and the root of the nail increases, in the course of a few weeks. When the nail is removed by any accident, it will be replaced by a new one, if the root be not injured. [Sidenote: 6. How are the hairs produced? Difference in their length?] 6. The hairs are produced in a similar manner; the skin forming depressions, or hair sacs, from the bottom of which they grow and are nourished (Fig. 14). They are found, of greater or less length, on almost all parts of the surface, except the palms of the hands and soles of the feet. On certain parts of the body, they grow to great length; on other parts they are so short, that they do not rise beyond the hair sac in which they originate. [Sidenote: 7. Root of the hair? Shaft? Firmness and softness of the hair?] 7. The bulb, or root, from which the hair arises, is lodged in a small pouch, or depression in the skin. The shaft is the part which grows out beyond the level of the skin. Its growth is altogether in one direction, in length alone. The outer part of the hair is quite firm, while its {44} interior is softer, and probably conveys the fluids by which it is nourished. The hair is more glossy in health than at other times. [Sidenote: 8. Office of the nail? Of the hair? Give the illustrations.] 8. The nail serves as a protection to the end of the finger, and also enables us to grasp more firmly, and to pick up small objects. The hair, too, is a protection to the parts it covers. On the head, it shields the brain from extremes of heat and cold, and moderates the force of blows upon the scalp. On the body, it is useful in affording a more extensive surface for carrying off the perspiration. [Sidenote: 9. On what does the complexion depend? Light and dark races? Freckles?] 9. COMPLEXION.--In the deeper cells of the cuticle lies a pigment, or coloring matter, consisting of minute colored grains. On this pigment _complexion_ depends; and, according as it is present in less or greater amount, occasions the difference of hue, that exists between the light and dark races of men, and between the blonde and brunette of the white races. Freckles are due to an irregular increase of coloring matter. [Sidenote: 10. Influence of the sun? How illustrated? Jews?] 10. The sun has a powerful influence over the development of this pigment, as is shown by the swarthy hue of those of the white race who have colonized in tropical climates. It is also well illustrated by the fact, that among the Jews who have settled in northern Europe, there are many who are fair complexioned, while those residing in India, are as dark as the Hindoos around them. [Sidenote: 11. What is an Albino? Where are Albinos found?] 11. An Albino is a person who may be said to have no complexion; that is, there is an entire absence of coloring matter from the skin, hair, and _iris_ of the eye. This condition more frequently occurs among the dark races, and in hot climates, although it has been observed in almost every race and clime. [Sidenote: 12. What are sebaceous glands? How do they act? Sebaceous glands of the face? How do they act?] 12. SEBACEOUS GLANDS.--There are in the skin certain {45} small glands, which produce an oily substance, called _sebaceous_ matter. These glands are little rounded sacs, usually connected with the hair-bulbs; and upon these bulbs, they empty their product of oil, which acts as a natural and adequate dressing for the hair (4, Fig. 14). A portion of the sebaceous matter passes out upon the surface, and prevents the cuticle from becoming dry and hard. The glands situated upon the face and forehead, open directly upon the skin. In these, the sebaceous matter is liable to collect, and become too hard to flow off naturally. [Sidenote: 13. Black points, called worms? Animalcules? Service performed by sebaceous matter?] 13. These glands on the face and forehead frequently appear, on the faces of the young, as small black points, which are incorrectly called "worms." It is true, that occasionally living animalcules are found in this thickened sebaceous matter, but they can only be detected by the aid of the microscope. This sebaceous matter acts not only to keep the skin flexible, and furnish for the hair an oily dressing, but it especially serves to protect the skin and hair, from the acridity arising from the perspiration. [Sidenote: 14. Perspiration? Sweat glands? Of what do they consist? Dimension of the tubes?] 14. THE PERSPIRATORY GLANDS.--The chief product of the skin's action is the perspiration. For the formation of this, there are furnished countless numbers of little sweat-glands in the true skin. They consist of fine tubes, with globe-like coils at their deeper extremity. Their mouths or openings may be seen with an ordinary magnifying glass, upon the fine ridges which mark the fingers. These tubes, if uncoiled, measure about one-tenth of an inch in length. In diameter, they are about one three-hundredth of an inch, and upon certain parts of the body there are not far from three thousand of these glands to the square inch. Their whole number in the body is, therefore, very great; and, in fact, it is computed if they were all united, end to end, their combined measurement would exceed three miles. {46} [Sidenote: 15. What is sensible perspiration? Insensible perspiration?] 15. THE SENSIBLE AND INSENSIBLE PERSPIRATION.--The pores of the skin are constantly exhaling a watery fluid; but, under ordinary circumstances, there is no moisture apparent upon the surface, for it evaporates as rapidly as it is formed. This is called insensible perspiration. Under the influence of heat or exercise, however, this fluid is excreted more abundantly, and appears on the surface in the form of minute, colorless drops. It is then termed sensible perspiration. [Sidenote: 16. Components of perspiration? Upon what does perspiration depend? Amount of perspiration daily?] 16. Water is the chief component of this fluid, there being about ninety-eight parts of water to two parts of solid matter. The quantity escaping from the body varies greatly, according to the temperature of the air, the occupation of the individual, and other circumstances. The average daily amount of this excretion, in the adult, is not far from thirty ounces, nearly two pints, or more than nine grains each minute. [Sidenote: 17. What does perspiration set free from the blood? What other service does perspiration perform? Explain the process.] 17. THE USES OF THE PERSPIRATION.--Besides liberating from the blood this large amount of water, with the effete matter it contains, the perspiration serves to regulate the temperature of the body. That is to say, as evaporation always diminishes temperature, so the perspiration, as it passes off in the form of fine vapor, cools the surface. Accordingly, in hot weather this function is much more active, and the cooling influence increases in proportion. When the air is already charged with moisture, and does not readily receive this vapor of the body, the heat of the atmosphere apparently increases, and the discomfort therefrom is relatively greater. [Sidenote: 18. Effect of interruption of excretion? What experiments are mentioned?] 18. The importance of this excretion is shown by the effects that often follow its temporary interruption, namely, headache, fever, and the other symptoms that accompany {47} "taking cold." When the perspiration is completely checked, the consequences are very serious. Experiments have been performed upon certain smaller animals, as rabbits, to ascertain the results of closing the perspiratory tubes. When they are covered by a coating of varnish impervious to water and gases, death ensues in from six to twelve hours; the attendant symptoms resembling those of suffocation. [Sidenote: 19. Give the story in relation to the boy covered with gold foil.] 19. It is related that, at the coronation of one of the Popes about three hundred years ago, a little boy was chosen to act the part of an angel; and in order that his appearance might be as gorgeous as possible, he was covered from head to foot with a coating of gold foil. He was soon taken sick, and although every known means were employed for his recovery, except the removal of his fatal golden covering, he died in a few hours. [Sidenote: 20. Give the quotation. Perspiration?] 20. THE IMPORTANCE OF BATHING.--From these considerations, it is evident that health must greatly depend upon the free action of the skin. "He who keeps the skin ruddy and soft, shuts many gates against disease." When the watery portion of the perspiration evaporates, the solid matter is left behind on the surface. There, also, remain the scales of the worn-out cuticle, and the excess of sebaceous matter. In order to secure the natural action of the skin, these impurities require to be removed by the frequent application of water. [Sidenote: 21. Ablution in warm climates? What advice is given?] 21. In warm climates, and during hot weather, ablution should be more frequently practised. For a person in good health, a daily cold bath is advisable. To this should be added occasionally a tepid bath, with soap, water alone not being sufficient to remove impurities of a greasy nature. Soap facilitates this, by forming with such substances a chemical mixture, which is readily soluble in water, and is by it removed from the body. {48} [Sidenote: 22. Liebig's maxim? What further is added?] 22. There is a maxim by the chemist Liebig, to the effect, that the civilization of a nation is high, in proportion to the amount of soap that it consumes; and that it is low, in proportion to its use of perfumes. In some degree, we may apply the same test to the refinement of an individual. The soap removes impurity; the perfume covers, while retaining it. [Sidenote: 23. What is said about cold bathing?] 23. THE DIFFERENT KINDS OF BATHS.--All persons are not alike able to use the cold bath. When the health is vigorous, and the system does not feel a shock after such a bath, a prompt reaction and glow upon the surface will show that it is beneficial. Where this pleasurable feeling is not experienced, but rather a chill and sense of depression ensues, we are warned that the system will not, with impunity, endure cold bathing. [Sidenote: 24. What is said about warm bathing?] 24. It should also be borne in mind, that the warm or hot bath cannot be continued so long, or repeated so frequently as the cold, on account of the enervating effect of unusual heat so applied to the body. For persons who are not in robust health, one warm bath each week is sufficient; this class should be careful to avoid every extreme in reference to bathing, clothing, and whatever greatly affects the action of the skin. [Sidenote: 25. What is said about sea-bathing?] 25. Sea-bathing is even more invigorating than fresh-water bathing. Those who cannot endure the fresh water, are often benefited by the salt-water baths. This may be accounted for, in part, by the stimulant action upon the surface, of the saline particles of the sea-water; but the exciting scenes and circumstances of sea-bathing also exert an important influence. The open-air exercise, the rolling surf, the genial weather, and usually the cheerful company, add to its intrinsic benefits. {49} [Sidenote: 26. What is said as to the time and manner of bathing?] 26. TIME AND MANNER OF BATHING.--A person in sound health may take a bath at almost any time, except directly after a full meal. The most appropriate time is about three hours after a meal, the noon-hour being probably the best. For the cold bath, taken rapidly, no time is better than immediately after rising. Those beginning the use of cold baths should first try them at 70° Fahr., and gradually use those of a lower temperature. From five to twenty minutes may be considered the proper limit of time to remain in a bath; but a sensation of chilliness is a signal to withdraw instantly, whether at home, or at the sea-side. Two sea-baths may be taken daily; one of any other kind is sufficient. [Sidenote: 27. Condition of the body when bathing? Direction, after bathing?] 27. The body should be warm, rather than cold, when stepping into the bath; and after it, the skin should be thoroughly dried with a coarse towel. It is best to continue friction until there is a sensation of warmth or "glow" throughout the entire surface. This reaction is the test of the good effects of the bath. If reaction is still incomplete, a short walk may be taken, especially in the sunshine. It is very congenial, however, both to health and comfort, to rest for a short time directly after bathing, or to take some light refreshment. This is better than severe exercise or a full meal. [Sidenote: 28. Bathing among the ancients? Baths of Rome?] 28. BATHING AMONG THE ANCIENTS.--The Romans and other nations of antiquity made great use of the vapor-bath as a means of preserving the health, but more particularly as a luxury. Their method was not unlike that employed in northern Europe at the present day. The public baths of Rome and other cities are among the grandest and most interesting monuments of ancient luxury and splendor; and from their ruins have been recovered some of the most beautiful works of art. {50} [Sidenote: 29. After the bath? Swimming among the ancients?] 29. The Thermæ, as the baths of Rome were called, were of great extent, built very substantially, and ornamented at vast expense. They were practically free to all, the cost of a bath having been less than a cent. It is related that some persons bathed seven times a day. After the bath their bodies were anointed with perfumed oil. If the weather was fine, they passed directly from the Thermæ into the gymnasium, and engaged in some gentle exercise previous to taking the midday meal. Between two and three in the afternoon was the favorite hour for this ancient luxury. Swimming was a favorite exercise, and a knowledge of it was regarded as necessary to every educated man. Their common expression, when speaking of an ignorant person, was, "He can neither read nor swim." [Sidenote: 30. The Sun-bath? The story of Pliny?] 30. THE SUN-BATH.--Some also were accustomed daily to anoint themselves, and lie or walk in apartments arranged for the purpose, with naked bodies exposed to the direct rays of the sun. There is an interesting allusion to this practice, in a letter of the younger Pliny to the historian Tacitus, describing the destruction of Pompeii by an eruption of Vesuvius. "My uncle," (Pliny the elder,) "was at that time in command of the fleet at Misenum. On the 24th of August, about one in the afternoon, my mother desired him to notice a cloud which seemed of unusual shape and dimensions. He had just returned from _taking the benefit of the sun_, and after a cold bath, and a slight repast, had retired to his study." Then follows a description of the destruction of Pompeii, and the death of the elder Pliny. [Sidenote: 31. Benefit of the sun? Effect upon plants? Skin?] 31. We may judge somewhat of "the benefits of the sun," by observing the unnatural and undeveloped condition of plants and animals which are deprived of light. Plants become blanched and tender; the fish of {51} subterranean lakes, where no light enters, are undersized, and have no eyes; tadpoles kept in the dark do not develop into frogs; men growing up in mines are sallow, pale, and deformed. Besides the well-known effect of solar light in tanning the skin, it also makes it thicker and better able to resist exposure; though the complexion may be thereby injured, the health gains more than compensate for the loss of beauty. "To make good the loss of the lily, where the sun has cast his ray, he seldom fails to plant the rose." [Sidenote: 32. Direction about clothing? Exposing limbs of children? Clothing, night and day?] 32. CLOTHING.--In reference to clothing, we are far more apt, in our changeful climate, to use too little than too much. An aphorism of Boerhaave, worth remembering, if not of adopting, is, "We should put off our winter clothing on midsummer's day, and put it on again the day after." He also says, "Only fools and beggars suffer from the cold; the latter not being able to get sufficient clothes, the others not having the sense to wear them." The practice of exposing the limbs and necks of young children, for the alleged purpose of "hardening" them, is quite hazardous. It is not to be denied that some seem to be made tough by the process; but it is so only with the rugged children, the delicate ones will invariably suffer under this fanciful treatment. As has been stated before, the skin is constantly acting, by night as well as by day. It is therefore conducive both to cleanliness and comfort to change entirely the clothing on retiring for the night. The day-clothing should be aired during the night, and the bedding should be aired in the morning, for the same reason. [Sidenote: 33. Cosmetics? Painters' colic?] 33. POISONOUS COSMETICS.--The extensive use of _cosmetics_ for the complexion is a fertile source of disease. The majority of these preparations contain certain poisonous mineral substances, chiefly lead. Now, the skin rapidly absorbs the fine particles of lead, and the system {52} experiences the same evil effects that are observed among the operatives in lead works and painters, namely, "painters' colic," and paralysis of the hands, called "wrist-drop." 34. Certain hair-dyes also contain lead, together with other noxious and filthy ingredients. These do not work as great harm as the cosmetics, since they are purposely kept away from the skin, but they rob the hair of its vitality. Eye-washes, too, are made from solutions of lead, and many an eye has been ruined by their use. They deposit a white metallic scale on the surface of the eye, which becomes a permanent obstruction to the vision. QUESTIONS FOR TOPICAL REVIEW. PAGE 1. What are the characteristics of the skin, and what office does it perform? 41 2. What can you state of the structure of the skin? 41 3. Describe the cuticle and tell its use. 41, 42 4. Describe the cutis or true skin and tell its use. 42 5. What can you state of the nature and growth of the nail? 42, 43 6. Of the nature and growth of the hair? 42, 43, 44 7. Of the offices performed by the nails and hair? 44 8. How is the difference in complexion in different persons accounted for? 44 9. How is the presence of freckles accounted for? 44 10. How does Nature provide a dressing for the hair? 44, 45 11. What other service do the sebaceous glands perform? 45 12. State what you can of the perspiratory glands. 45 13. What is the difference between sensible and insensible perspiration? 46 14. State the uses and importance of perspiration. 46, 47 15. What impurities gather naturally on the skin? 47 16. Repeat what is said of the importance of bathing. 47, 48 17. When should we indulge in cold, warm, and sea bathing? 48, 49 18. What is the effect in each case? 48 19. What directions are given as to the time and manner for bathing? 49 20. What is related of bathing among the ancients? 49, 50 21. What is related to show the antiquity of sun-bathing? 50 22. What are the effects of sun-bathing? 50, 51 23. What directions are given in relation to clothing the body? 51 24. What can you state of poisonous cosmetics? 51, 52 25. Of hair-dyes and eye-washes? 52 * * * * * {53} CHAPTER IV. THE CHEMISTRY OF FOOD. _The Source of Food--Inorganic Substances--Water--Salt--Lime--Iron--Organic Substances--Albumen, Fibrin, and Casein--The Fats or Oils--The Sugars, Starch, and Gum--Stimulating Substances--Necessity of a Regulated Diet._ [Sidenote: 1. The term food? Source of food? Need of preparing food?] 1. THE SOURCE OF FOOD.--The term _food_ includes all those substances, whether liquid or solid, which are necessary for the nourishment of the body. The original source of all food is the earth, which the poet has fitly styled the "Mother of all living." In her bosom, and in the atmosphere about her, are contained all the elements on which life depends. But man is unable to obtain nourishment directly from such crude chemical forms as he finds in the inorganic world. They must, with a few exceptions, be prepared for his use, by being transformed into new and higher combinations, more closely resembling the tissues of his own body. [Sidenote: 2. Usefulness and hurtfulness of plants? What then must man do? Parts of the same plant or tree?] 2. This transformation is effected, first, by the vegetable world. But all plants are not alike useful to man; while some are absolutely hurtful. Accordingly, he must learn to discriminate between that which is poisonous and that which is life-supporting. Again, all parts of the same plant or tree are not alike beneficial: in some, the fruit, in others, the leaves, and in others, the seeds only are sufficiently refined for his use. These he must learn to select; he must also learn the proper modes of preparing each kind for his table, whether by cooking or other processes. {54} [Sidenote: 3. Certain forms of vegetable creation? Example of the bee? Cattle? The inference?] 3. Again, certain forms of the vegetable creation which are unfit, in their crude state, for man's food, and which he rejects, are chosen as food by some of the lower animals, and are, by them, made ready for his use. Thus the bee takes the clover, that man cannot eat, and from it collects honey. The cattle eat the husks of corn and the dried grass, that are by far too coarse for man, and in their own flesh convert them into tissues closely resembling his muscular tissue. In this way, by the aid of the transforming processes of the vegetable and animal creations, the simple chemical elements of the mineral kingdom are elaborated into our choice articles of food. [Sidenote: 4. What classification? Define organic substances. Inorganic. Organic, how spoken of? The inorganic? Water and salt?] 4. INORGANIC SUBSTANCES.--The substances we use as food are classified as _organic_ and _inorganic_. By organic substances are meant those derived from living forms, such as vegetables and animals. Inorganic substances are those simpler inanimate forms which belong to the mineral kingdom. The former alone are commonly spoken of as food, but the latter enter very largely into the constitution of the body, and must therefore be present in our food. With the exception of two articles, water and common salt, these substances only enter the system when blended with organic substances. [Sidenote: 5. Water in physiology? Where found? Computation? Water in the teeth? Muscle, tendons, and ligaments? How ascertained? Water in the fluids of the body? What is the advantage?] 5. WATER.--Water, from a physiological point of view, is the most important of all the articles of food. It is everywhere found in the body, even in the bones and the teeth. It has been computed that as large a proportion as two-thirds of the body is water. The teeth, the densest of the solids in the human system, contain ten per cent. of water. The muscles, tendons, and ligaments are more than half water; for it is found that they lose more than half their {55} weight when dried with moderate heat. But it is in the _fluids_ of the body that water is found most abundantly. It gives to them the power of holding a great variety of substances in solution, and is the great highway by which new supplies are conveyed to the point where they are required, and by which old particles of matter, that have served their uses, are brought to the outlets of the body to be thus removed from the system. [Sidenote: 6. Length of time man can do without food or water? Give the comparison? Bulk of drinks? Constituent of meats, etc.? Fruits?] 6. Man can remain a longer time without solid food than without water. He may be deprived of the former for ten to twelve hours without great suffering, but deprivation of water for the same length of time will produce both severe pain and great weakness. The food should contain not less than two parts of water to one of solid nutriment. Water constitutes the great bulk of all our drinks, and is also a large constituent of the meats, vegetables, and fruits which come upon the table. Fruits, especially, contain it in great abundance, and, in their proper season, furnish most agreeable and refreshing supplies of the needed fluid. [Sidenote: 7. Salt, how obtained? Where found? In the human body? Importance of salt? What else can you state of the value of salt?] 7. COMMON SALT.--Salt, or sodium chloride, as an article of food, is obtained chiefly from the mineral kingdom; although plants contain it in small quantities, and it is also found in the tissues of nearly all animals used as food. In the human body, it is an ingredient of all the solids and fluids. The importance of salt to animal life in general, is shown by the great appetite for it manifested by domestic animals, and also by the habitual resort of herds of wild beasts to the "salt-licks" or springs. In those parts of the world where salt is obtained with difficulty, man places a very high price upon it. [Sidenote: 8. Experiments upon animals?] 8. Experiments upon domestic animals show that the withdrawal of salt from their food, not only makes their {56} hides rough and causes the hair to fall out, but also interferes with the proper digestion of food. If it be withheld persistently, they become entirely unable to appropriate nourishment, and die of starvation. [Sidenote: 9. Salt, how taken into the system? Its use in cooking? Consumption?] 9. Salt is usually taken into the system in sufficient quantities in our food. Even the water we drink often has traces of it. The habitual use of much salt in cooking, or as a seasoning at the table, is not wise; and while it may not lead to consumption, as some writers declare, it is a bad habit in itself, and leads to the desire for other and more injurious condiments. [Sidenote: 10. Lime in the bones? What does it impart? Chief ingredient of the bones and teeth? Where else found?] 10. LIME.--This is the mineral substance which we have spoken of before as entering very largely into the composition of the bones. It is the important element which gives solidity and permanence to the framework upon which the body is built. Calcium tri-phosphate, or "bone-earth," is the chief ingredient of the bones and teeth, but is found in the cartilages and other parts of the body in smaller quantities. [Sidenote: 11. How does lime find its way into the body? Early life? Effect of its derivation?] 11. How does this substance find its way into the body? Meat, milk, and other articles obtained from the animal kingdom contain it, and it is abundantly stored away also in the grains from which our bread is made, in wheat, rye, and Indian corn. In early life, while the body is growing, the supplies of this substance should be carefully provided. The evil effects of the deprivation of it are too often and painfully evident in the softening of the bones, and in the predisposition to curvature of the spine--deformities which are most deplorable and which continue through life. [Sidenote: 12. Iron, its abundance and diffusion? Where found? What part of the blood is it? How supplied to the system? In case of loss of blood or wasting disease?] 12. IRON.--This substance is probably the most abundant and widely diffused of the metals. It is found in {57} most of the vegetables, and is a very important component of animal tissues. It enters into the composition of human blood in about one part per thousand. Ordinarily, the food conveys to the system enough iron for its use, but it must sometimes be introduced separately as a remedy, especially after great loss of blood, or after some wasting disease. Under its influence the blood seems to be rapidly restored, and a natural color of the lips and skin replaces the pallor caused by disease. [Sidenote: 13. Soda, potash, and magnesia? How do they occur?] 13. OTHER INORGANIC SUBSTANCES.--In addition to the substances mentioned, the mineral kingdom supplies compounds of soda, potash, and magnesia, which are essential for the use of the body. They occur in small quantities in the body, and enter it in combination with the various articles of diet. [Sidenote: 14. Organic substances, whence derived? What do they comprise? Groups?] 14. ORGANIC SUBSTANCES.--These substances are derived from the vegetable and animal creations. They comprise all those articles which are commonly spoken of as "food," and which are essential to sustain the body in life and strength. They are divided into three groups, namely: the Albuminoid substances, the Fats, and Sugars. [Sidenote: 15. The Albuminoid class, includes what? These compounds constitute what? The food? Their importance? Their properties?] 15. THE ALBUMINOIDS.--This class includes three important nutritive substances--(1) _Albumen_, which gives it its name; (2) _Fibrin_, including _gluten_; and (3) _Casein_. These compounds constitute a large part of the human body, and the food contains them in proportionally large quantities. Their importance is so great, and the system so promptly suffers from their absence, that they have been styled the "_nutritious_ substances." The properties which they hold in common are, that they do not crystallize, and have a jelly-like form, except when heat is applied to them, when they harden, or _coagulate_. {58} [Sidenote: 16. Decomposition? Effect of cold? Illustrations? Elephants?] 16. They likewise decompose, or _putrefy_, under the influence of warmth and moisture. Hence the decay of all dead animal tissues. Cold arrests this process. It is well known that milk, eggs, and the like, "keep" much longer in winter than at other seasons. The bodies of elephants, caught in the ice many hundred years ago, are occasionally borne by the icebergs to the coast of Siberia, completely frozen, but preserved almost perfectly in form and limb. [Sidenote: 17. In what substances does albumen exist? What further is said of the egg?] 17. ALBUMEN exists in milk, meat, the grains, and the juices of many plants; but the purest form is obtained from the white of egg. When we consider that an egg is composed chiefly of albumen and water--namely, six parts in seven; and when we also consider the numerous, diverse, and complex tissues--the muscles, bones, internal organs, bill, claws, and feathers--with which the chick is equipped on leaving his shell, we are impressed with the importance of these apparently simple constituents of the food and body. [Sidenote: 18. Fibrin, gluten, clotting of the blood?] 18. FIBRIN is derived from meats, and exists in the blood both of man and the lower animals. _Gluten_, or vegetable fibrin, resembles closely true fibrin, and is abundantly furnished in wheat and other grains from which flour is commonly made. Animal fibrin coagulates spontaneously when it is removed from the body, and thus causes the "clotting" of the blood. [Sidenote: 19. Casein? Its coagulation? Effect of rennet? Making of cheese?] 19. CASEIN is the curdy ingredient of milk, and a highly important food-substance. Its coagulation in milk takes place not from heat, but by the addition of an acid, and also when milk becomes sour from exposure to the air. It is commonly effected, however, by introducing a piece of _rennet_, a preparation made from a calf's stomach. The _curds_, or casein, may then be separated from the _whey_, {59} and made into cheese, by pressing it sufficiently to drive off the water. [Sidenote: 20. What are the fats? The oils? How supplied? How alike? Emulsifying? Example? How do we know it?] 20. THE FATS OR OILS.--This is the second group of organic foods. Those which are more solid are called _fats_: the more fluid ones are the _oils_. Oleaginous substances are supplied in both animal and vegetable food; but, from whatever source derived, they are chemically much alike. They are insoluble in water, and yet they unite readily with the watery fluids of the body, and are by them conveyed to its various parts for their nourishment. This is due to their property of "emulsifying;" that is, they are held in suspension, in a finely divided state, in water. Ordinary milk is an example of an _emulsion_. We know that it contains fat; for butter is obtained from it, and, under the microscope, the minute oil-globules may be distinctly seen. [Sidenote: 21. Whence are fatty articles of food derived?] 21. In our country and climate, and also in colder climates, fatty articles of food are principally derived from the animal creation, such as meat or flesh, milk and butter. But most of the bread-stuffs contain more or less fat or oil; Indian meal as much as nine parts in a hundred. [Sidenote: 22. Appetite of persons in cold climates? What do they require? Upon what must they rely? Why? The Esquimaux? Laplander? Olive and palm?] 22. Among persons living in cold climates, the appetite for oleaginous food is especially eager; and they require large quantities of it to enable them to resist the depressing influences of cold. Since vegetation is scanty and innutritious, and the waters of the frozen regions abound in animal life, they must rely wholly upon a diet derived from the latter source. The Esquimaux consumes daily from ten to fifteen pounds of meat or blubber, a large proportion of which is fat. The Laplander will drink train-oil, and regards tallow-candles as a great delicacy. In hot climates, on the contrary, where flourish the olive {60} and the palm, this kind of food may be obtained from vegetable sources in abundant quantities. [Sidenote: 23. Which are the third of the organic groups? What do they embrace? Points of resemblance?] 23. THE SUGARS, OR THE SACCHARINE SUBSTANCES.--These constitute the third, and last, group of the organic substances, which are employed as food. This group embraces, in addition to the different kinds of _Sugar_, the varieties of starch and gum, from whatever source derived. The two substances last named do not, at first sight, present many points of similarity to sugar; but they closely resemble it in respect to their ultimate chemical composition, being made up of the same elements, in nearly the same proportions. And their office in the system is the same, since they are all changed into sugar by the processes of digestion. [Sidenote: 24. Origin of the sugars? Ordinary sugar? Beetroot? Maple-sugar? Grape-sugar? Cane-sugar?] 24. SUGAR is chiefly of vegetable origin; the animal varieties being obtained from honey and milk. The most noticeable characteristic of this substance is its agreeable, sweet taste, which makes it everywhere a favorite article of food. But this quality of sweetness is not possessed by all the varieties of sugar in the same degree; that obtained from milk, for instance, has a comparatively feeble taste, but rather imparts a gritty feeling to the tongue. The other important properties of sugar are, its power to crystallize when evaporated from watery solutions, such as the juices of many plants; a tendency to ferment, by which process alcohol is produced; and a ready solubility in water. This latter quality renders it very easy of digestion, and more so than any other of the saccharine group. It is computed that the annual production of sugar, in all parts of the world, is more than one million of tons. The kind of sugar that is in ordinary use, in this country, is prepared from the juice of the sugar-cane, which contains eighteen per cent. of sugar. In France it is manufactured from the {61} beet root, which holds about nine per cent.; the maple-tree of our climate yields a similar sugar. The sweet taste of fruits is due to the presence of grape-sugar: the white grains seen on raisins belong to this variety. Cane-sugar is more soluble than the latter, and has twice the sweetening power. [Illustration: FIG. 15.--GRANULES OF POTATO STARCH.] [Sidenote: 25. Starch, how widely distributed? Its qualities? Its constituents? Its solubility?] 25. STARCH.--This is the most widely distributed of the vegetable principles. It is tasteless, inodorous, and does not crystallize. It consists of minute rounded granules, which, under the microscope, reveal a somewhat uniform structure (Fig. 15). Starch will not dissolve in cold water, but in boiling water the small grains burst open, and may then be dissolved and digested. [Sidenote: 26. How much starch in bread-stuffs? In rice? Unripe fruits? Ripe fruits?] 26. The bread stuffs, wheat, corn, and rye flours, are more than one-half starch. Rice, which is the "staff of life" to one-third of the human family, contains eighty per cent. Unripe fruits have much starch in them, which renders them indigestible when eaten uncooked; for the grains of raw starch are but slightly acted upon within the body. But, under the potent chemistry of the sun's ray, this crude material is converted into sugar. Thus are the fruits prepared by the careful hand of Nature, so that when ripe they may be freely used without further preparation. [Sidenote: 27. Gum, where found? Its composition? Gum Arabic?] 27. GUM is commonly found in those articles which {62} also contain starch; and has the same chemical composition as the latter, but is much less nutritious. In the East, gum-arabic and similar substances are largely employed as food. Persons who travel by caravan across vast, sandy deserts, find such substances well adapted to their wants, since they are not perishable, and are easily packed and carried. [Sidenote: 28. The three classes of food principles? What besides? What is said of them? Name the articles not nutritious.] 28. STIMULATING SUBSTANCES.--The three classes of food-principles already considered--the Albuminoids, the Fats, and the Sugars--comprise all the more important organic ingredients of our food. There are, besides, a great variety of coloring and flavoring matters that stimulate or increase the appetite for food by appealing to the eye and taste; but they are not nutritious, and are quickly separated from the truly useful substances, and do not long remain in the body. Among these may be classed spices, flavors of fruits, tea, coffee, and vegetable acids. [Sidenote: 29. What is said of experiments that have been tried?] 29. NECESSITY OF A REGULATED DIET.--A great variety of experiments have been tried in order to test the relative value of the different nutritive principles. They have been practised to some extent upon man, but chiefly upon those inferior animals which require a similar diet to man. [Sidenote: 30. What has been demonstrated in the first place? Example? Second demonstration? Example? Give the illustration in relation to convertibility.] 30. By this means it has been demonstrated that--first, when any one of these substances is eaten exclusively, the body is imperfectly nourished, and life is shortened. Dogs fed exclusively upon either albumen, fat, or sugar, soon die of starvation. Second, a diet long deprived of either of these principles, is a fertile cause of disease; for example, on ship-board, where fresh vegetables are not dealt out for a long period, _scurvy_ becomes prevalent among the sailors. They are, however, to a certain extent mutually convertible, and thus the missing article is indirectly supplied. For {63} instance, sugar changes to fat in the body; and hence, as is well known, the "hands" on a sugar plantation grow fat during the sugar season, by partaking freely of the ripened juices of the cane. 31. That is the best diet therefore which contains some of each of these principles, in due proportion; and that is the worst which excludes the most of them. The cravings and experience of man had unerringly guided him to a correct regulation of his diet, long before the chemistry of food was understood; so that his ordinary meals long ago combined these various principles, the necessity and value of which are now explained. QUESTIONS FOR TOPICAL REVIEW. PAGE 1. What is understood by the term food? 53 2. What can you state in relation to the source of food? 53 3. What discriminations and selections are necessary? 53, 54 4. How can you tell the organic from the inorganic substances? 54 5. What relative position does water hold as an article of food? 54 6. In what parts of the body is water found? 54, 55 7. In what articles that we eat is it found? 55 8. If you were required to go without water or solid food for a number of days, which would you prefer to have, and why? 55 9. What can you state of the importance of salt as an article of food? 55, 56 10. How abundant is salt, and how does it find its way into the human system? 55, 56 11. What can you state of the importance of lime in the body? 56 12. What, of the importance of iron? 56, 57 13. What further is stated of other inorganic substances? 57 14. What in relation to organic substances? 57 15. What can you state in relation to the albuminoids? 57, 58 16. What, in relation to albumen? 58 17. What, in relation to casein? 58, 59 18. In relation to the fats or oils, and how generally consumed? 59, 60 19. What do we understand by the sugars or saccharine substances? 60 20. State what you can of sugar--its origin and various qualities. 60, 61 21. Of starch--its varieties and qualities. 61 22. Of the abundance of starch, and its importance as a food principle. 61 23. What is stated in relation to stimulating substances? 62 24. Of the necessity for regulation in diet? 62, 63 * * * * * {64} CHAPTER V. FOOD AND DRINK. _Necessity for Food--Waste and Repair--Hunger and Thirst--Amount of Food--Renovation of the Body--Mixed Diet--Milk--Eggs--Meat--Cooking--Vegetable Food--Bread--The Potato--Fruits--Purity of Water--Action of Water upon Lead--Coffee, Tea, and Chocolate--Effects of Alcohol._ [Sidenote: 1. What follow activity? Examples? Necessity for food?] 1. NECESSITY FOR FOOD.--Activity is everywhere followed by waste. The engine uses up coal and water to produce motion, the stream wears away its bank, the growing corn-blade draws tribute from the soil. When the human body acts, and it is always in action during life, some of its particles are worn out and thrown off. This waste must constantly be repaired, or the body suffers. In this fact is seen the necessity for food. The particles, thus worn out, being henceforth useless, are removed from the body. Our _food_ and _drink_ are rapidly transformed into a new supply of living, useful material, to be in turn used up and replaced by a fresher supply. [Sidenote: 2. Give the theory in relation to waste and repair.] 2. WASTE AND REPAIR.--In this way the healthful body, though always wasting, is always building up, and does not greatly change in size, form, or weight. At two periods of life the processes of waste and repair are not exactly balanced. In early life the process of building up is more active, and in consequence the form is plump, and the stature increases. Repair now exceeds waste. On the other hand, when old age comes on, the wasting process is more active, the flesh and weight diminish, the skin falls in wrinkles, and the senses become dull. Only during the prime of life--from about twenty to sixty years of age--is the balance exact between loss and gain. {65} [Sidenote: 3. System deprived of food? Warning? What is the pain? How proved?] 3. HUNGER AND THIRST.--When the system is deprived of its supply of solid food during a longer time than usual, nature gives warning by the sensation of hunger, to repair the losses that have taken place. This sensation or pain appears to be located in the stomach, but it is really a distress of the system at large. Let a sufficient quantity of nourishment be introduced into the system in any other way than by the mouth, and it will appease hunger just as certainly as when taken in the usual manner. [Sidenote: 4. Feeling of thirst? Seat of the pain? How proved? Time a person can exist without food?] 4. The feeling of thirst, in like manner, is evidence that the system is suffering from the want of water. The apparent seat of the distress of thirst is in the throat; but the injection of water into the blood-vessels is found to quench thirst, and by the immersion of the body in water, the skin will absorb sufficient to satisfy the demands of the system. The length of time that man can exist without food or drink is estimated to be about seven days. If water alone be supplied, life will last much longer; there being cases recorded where men have lived twenty days and over, without taking any solid food. [Sidenote: 5. Amount of food required? The young and others? Those living in hot and cold climates? Habits?] 5. QUANTITY OF FOOD.--The quantity of food required varies greatly, according to the individual and his mode of life. The young, and others who lead active lives, or who live in the open air, require more food than the old, the inactive, or the sedentary. Those who live in cold regions require more than the inhabitants of hot climates. Habit, also, has much to do with the quantity of food required. Some habitually eat and drink more than they actually need, while a few eat less than they should. [Sidenote: 6. Quantity of food daily? How divided? Compare with the weight of the body?] 6. The average daily quantity of food and drink for a healthy man of active habits is estimated at six pounds. This amount may be divided in about the following {66} proportions: the mineral kingdom furnishes three and one-half pounds, including water and salt; the vegetable kingdom, one and one-half pounds, including bread, vegetables, and fruits; the animal kingdom, one pound, comprising meat, eggs, butter, and the like. This quantity is about one twenty-fourth the weight of the body, as it is generally computed; the average weight of an adult man being placed at 140 pounds. A man, therefore, consumes an amount of solid and liquid nutriment every twenty-four days equal in weight to that of his body, a corresponding amount being _excreted_, or removed from the system in the same time. [Sidenote: 7. How often then might the body be renewed? Why is it not? Opinion? How correct? What further is stated?] 7. RENOVATION OF THE BODY.--By this process, so far as weight is concerned, the body might be renewed every twenty-four days; but these pounds of food are not all real nutriment. A considerable portion of that which we eat is innutritious, and though useful in various ways, is not destined to repair the losses of the system. An opinion has prevailed that the body is renewed throughout once in seven years; how correct this may be it is not easy to decide, but probably the renovation of the body takes place in a much shorter period. Some parts are very frequently renewed, the nutritive fluids changing more or less completely, several times during the day. The muscles, and other parts in frequent exercise, change often during a year; the bones not so often, and the enamel of the teeth probably never changes after being once fully formed. [Sidenote: 8. Habits of nations? Give the different cases.] 8. MIXED DIET.--The habits of different nations in respect to diet exhibit the widest and strangest diversity. The civilized, cook their food, while savages often eat it in a raw state. Some prefer it when fresh, others allow it to remain until it has become tainted with decay. Those dwelling in the far north subsist almost wholly on {67} animal food, while those living in hot climates have bountiful supplies of delicious fruits with which to satisfy all their bodily wants. One race subsists upon the banana, another upon the blubber of seals. In temperate climates, a diet composed partly of vegetable and partly of animal food is preferred. [Sidenote: 9. The point to consider? Vegetable diet? Louis Cornaro? John the Baptist?] 9. The important point to consider is, however, not one of origin, but whether the chemical principles (mentioned in the last chapter) enter into the composition of the diet. A purely vegetable diet may be selected which would contain all the principles necessary to sustain life. It is recorded of Louis Cornaro, a Venetian noble, that he supported himself comfortably for fifty-eight years on a daily allowance of twelve ounces of vegetable food, and about a pint of light wine. On the other hand, the food of John the Baptist, consisting of "locusts and wild honey," is an example of the sustaining power of a diet chiefly animal in its origin. [Sidenote: 10. What has been found in our climate? Exclusive vegetable diet?] 10. In our climate, those who lead active lives crave an allowance of animal food; and it has been found by experience that with it they can accomplish more work and are less subject to fatigue, than without it. Among nations where an exclusively vegetable diet is employed, indigestion is a disorder especially prevalent. [Sidenote: 11. Necessity for change in diet? Continuous use of the same diet? Exception? Why? Too rich diet? Horses?] 11. The necessity for occasionally changing or varying the diet, is seen in the fact that no single article comprises all the necessary principles of food, and that the continuous use of any one diet, whether salt or fresh, is followed by defective nutrition and disease. There is one exception to this rule: in infancy, milk alone is best calculated to support life; for then the digestive powers are incompletely developed, and the food must be presented in the simplest form possible. It should also be remembered {68} that too rich diet is injurious, just as truly as one that is inadequate. When the food of horses is too nutritious, instinct leads them to gnaw the wood-work of their mangers. [Sidenote: 12. Milk as a model food? Cow's milk? The constituents when separated?] 12. DIFFERENT ARTICLES OF DIET--MILK.--Milk is the earliest nutriment of the human race, and in the selection and arrangement of its constituents, may be regarded as a model food, no other single article being capable of sustaining life so long. Cow's milk holds casein, one of the albuminoids, about five parts in one hundred; a fatty principle, when separated, known as butter, about four parts; sugar of milk four parts; water and salts eighty-seven parts. The casein and fatty substance are far more digestible in milk, than after they have been separated from it in the form of cheese and butter. [Sidenote: 13. Milk as a beverage? Milk sold in cities? How to detect the cheat?] 13. Since milk, in itself, is so rich an article of food, the use of it as a beverage is unwise, unless the quantity of the other articles consumed be reduced at the same time. The milk sold in cities is apt to be diluted with water. The way to detect the cheat is by testing the specific gravity of the article. Good milk is about 1030; skimmed milk 1035; but milk diluted one-fifth is 1024. An instrument called the lactometer is also used, by which the amount of cream present is ascertained. [Sidenote: 14. Composition of eggs? Yolk? How should eggs be eaten? Why? How boiled? Why?] 14. EGGS.--The egg is about two-thirds water, the balance is pure albumen and fat in nearly equal proportions. The fat is in the yolk, and gives it its yellow color. Eggs contain none of the sugar-principles, and should be eaten with bread or vegetables that contain them. Soft-boiled eggs are more wholesome than those which are hard-boiled or fried, as the latter require longer time to digest. [Sidenote: 15. Meats, whence derived? Why important? Flesh of young animals?] 15. MEATS.--The meats, so called, are derived from the muscular parts of various animals. They are most {69} important articles of food for adults, inasmuch as they are richly stored with albuminoid substances, and contain more or less fat. Such food is very nourishing and easily digested if eaten when fresh,--veal and pork being exceptions. The flesh of young animals is more tender and, in general, more digestible than that of older ones. All meat is more tough immediately after the killing of the animal, but improves by being kept a certain length of time. [Sidenote: 16. Preference of persons? Venison? Mutton? Cheese? Uncooked flesh?] 16. Some persons prefer flesh that has begun to show signs of decomposition, or is unmistakably putrid. By some, venison is not considered to have its proper flavor until it is tainted. In England, people prefer mutton that is in a similar condition, just as on the continent of Europe many delight in cheese that is in a state of decomposition. In certain less civilized countries flesh is not only eaten uncooked, but in a mouldy, rotten condition. The use of such food is not always immediately injurious, but it predisposes to certain diseases, as indigestion and fevers. [Sidenote: 17. Cold as a preserver? Meat in Russia? Beef and pork, how preserved? Salted meat as food? Scurvy?] 17. Cold is one means of preserving meat from decay. In the markets of northern Russia, the frozen carcases of animals stand exposed for sale in the winter air for a considerable time, and are sawn in pieces, like sticks of wood, as the purchases are made; such meat, when thawed, being entirely fit for food. Beef and pork are preserved by salting down in brine, and in this condition may be carried on long voyages or kept for future use. Salted meat is not as nutritious as fresh, since the brine absorbs its rich juices and hardens its fibres. Long continued use of salt meats, without fresh vegetables, gives rise to the disease called scurvy, formerly very prevalent on shipboard and in prisons; but now scarcely known. [Sidenote: 18. The antiquity of the custom of cooking food? Object of cooking? The oyster? Raw meat as an occasional food?] 18. COOKING.--The preparation of food by the agency {70} of fire is of almost universal practice, even among the rudest nations. The object of cooking is to render food more easy of digestion by softening it, to develop its flavor, and to raise its temperature more nearly to that of the body. A few articles of flesh-food are eaten uncooked in civilized lands, the oyster being an instance. Raw meat is occasionally eaten by invalids with weak digestive powers, and by men training for athletic contests. [Sidenote: 19. Effect of boiling meat? How may the cooking be done? The proper method? Effect? Making of soup?] 19. In boiling meat, the water in which it is placed tends to dissolve its nutrient juices. In fact, the cooking may be so conducted as to rob the meat of its nourishment, its tenderness, and even of its flavor. The proper method, in order to preserve or promote these qualities, is to place the meat in boiling water, which, after a few minutes, should be reduced in temperature. In this way the intense heat, at first, coagulates the exterior layers of albumen, and imprisons the delicate juices; after that, moderate heat best softens it throughout. When soup is to be made, an opposite course should be pursued; for then the object is to extract the juices and reject the fibre. Meat, for such purpose, should be cut in small pieces and put into cold water, which should then be gradually raised to boiling heat. [Sidenote: 20. Roasting? How should it be done? Give the philosophy of the process. Frying?] 20. Roasting is probably the best method of cooking meat, especially "joints" or large pieces, as by this process the meat is cooked in its own juices. Roasting should begin with intense heat, and be continued at a moderate temperature, in order to prevent the drying out of the nutritious juices, as by this process an outer coating or crust of coagulated albumen is formed. During this process the meat loses one-fourth of its weight, but the loss is almost wholly water, evaporated by the heat. Too {71} intense or prolonged heat will dry the meat, or burn it. Frying is the worst possible method, as the heated fat, by penetrating the meat, or other article placed in it, dries and hardens it, and thus renders it indigestible. [Sidenote: 21. What is "Trichina?" How guarded against?] 21. TRICHINA.--It should be remembered that ham, sausages, and other forms of pork, should never be eaten in a raw or imperfectly cooked condition. The muscle of the pig is often infested by a minute animal parasite, or worm, called _trichina spiralis_. This worm may be introduced alive into the human body in pork food, where it multiplies with great rapidity, and gives rise to a painful and serious disease. This disease has been prevalent in Germany, and cases of it occur from time to time in this country. [Sidenote: 22. What part of fish is eaten? What does it resemble? Fish as food for digestion? Fish as a diet?] 22. FISH.--The part of fish that is eaten is the muscle, just as in the case of the meats and poultry. It closely resembles flesh in its composition, but is more watery. Some varieties are very easy of digestion, such as salmon, trout, and cod; others are quite indigestible, especially lobsters, clams, and shell-fish generally. A diet in which fish enters as the chief article, is ill adapted to strengthen mind or body, while its continued use is said to be the fertile source of nearly every form of disease of the skin. Some persons are so constituted that they can eat no kind of fish without experiencing unpleasant results. [Sidenote: 23. List of vegetable articles? Usefulness of the different vegetables? Strychnia? What further is said in relation to the nourishing and other qualities of vegetables?] 23. VEGETABLE FOOD.--The list of vegetable articles of diet is a very long one, including the grains from which our bread-stuffs are made, the vegetables from the garden, and the fruits. All the products of the vegetable kingdom are not alike useful. Some are positively hurtful; indeed, the most virulent poisons, as strychnia and prussic acid, are obtained from certain vegetables. Again, of such {72} articles as have been found good for food, some are more nourishing than others: some require very little preparation for use, while others are hard and indigestible, and can only be used after undergoing many preparatory processes. Great care must therefore be exercised, and many experiments made, before we can arrive at a complete knowledge in reference to these articles of diet. Tea, coffee, and other substances from which drinks are made, are of vegetable origin. [Sidenote: 24. Wheat? "Staff of life?" White flour? Hard-grain wheats? Bolting? Graham bread?] 24. BREAD.--Wheat is the principal and most valuable kind of grain for the service of man. Bread made from wheat-flour has been in use for many hundreds of years, and on this account, as well as because of its highly nourishing properties, has been aptly called "the staff of life." We never become tired of good bread as an article of daily food. The white kinds of flour contain more starch and less gluten than the darker, and are therefore less nutritious. The hard-grain wheat yields the best flour. In grinding wheat, the chaff or bran is separated by a process called "bolting." Unbolted flour is used for making brown or Graham bread. [Sidenote: 25. Leavened bread? Unleavened? Hot bread?] 25. The form of bread most easily digested is that which has been "leavened," or rendered porous by the use of yeast, or by some similar method. Unleavened bread requires much more mastication. Hot bread is unwholesome, because it is not firm enough to be thoroughly masticated, but is converted into a pasty, heavy mass that is not easily digested. [Sidenote: 26. Wheaten bread? Bread and butter? Experiment on the dog?] 26. Wheaten bread contains nearly every principle requisite for sustaining life, except fat. This is commonly added in other articles of diet, especially in butter,--"bread and butter," consequently, forming an almost perfect article of {73} food. The following experiment is recorded: "A dog eating _ad libitum_ of white bread, made of pure wheat, and freely supplied with water, did not live beyond fifty days. He died at the end of that time with all the signs of gradual exhaustion." Death took place, not because there was anything hurtful in the bread, but because of the absence of one or more of the food-principles. [Sidenote: 27. State what is said of the Irish potato?] 27. THE POTATO.--The common or Irish potato is the vegetable most extensively used in this country and Great Britain. Among the poorer classes in Ireland it is the main article of food. While it is not so rich in nutritious substances as many others, it has some very useful qualities. It keeps well from season to season, and men do not weary of its continuous use. It is more than two-thirds water, the balance being chiefly starch, with a little albumen. [Sidenote: 28. Sweet potato? Nightshades? Potatoes when germinating?] 28. The sweet potato differs from the white or common, in containing more water and a small proportion of sugar. The common potato and the tomato belong to the same botanical order as the "nightshades," but do not possess their poisonous qualities, unless we except potatoes that are in the process of germination or sprouting, when they are found injurious as food. [Sidenote: 29. Fruits? Use of ripe fruit? Nutriment they contain? Starch in unripe fruits? Cooking of unripe fruits?] 29. FRUITS.--These are produced, in this country, in great abundance, and are remarkable alike for their variety and delicious flavor; consequently they are consumed in large quantities, especially during the warmer months. The moderate use of ripe fruits, in their season, is beneficial, because they offer a pleasant substitute for the more concentrated diet that is used in cold weather. The amount of solid nutriment they contain is, however, small. The percentage of water in cherries is seventy-five, in grapes eighty-one, in apples eighty-two. Unripe fruits contain starch, which, during the process of ripening, {74} is converted into sugar. Such fruits are indigestible and should be avoided: cooking, however, in part removes the objections to them. [Sidenote: 30. How should drinking-water be as regards color and smell? Chemically pure water? How obtained? Agreeableness of perfectly pure water?] 30. PURE WATER.--It is important that the water we drink and use in the preparation of food should be pure. It should be clear and colorless, with little or no taste or smell, and free from any great amount of foreign ingredients. Chemically pure water does not occur in nature: it is only obtained by the condensation of steam, carefully conducted, and is not as agreeable for drinking purposes as the water furnished by springs and streams. Rain-water is the purest occurring in nature; but even this contains certain impurities, especially the portion which falls in the early part of a shower; for in its descent from the clouds, the particles floating in the air are caught by the falling drops. [Sidenote: 31. Spring and well water? Whence the sparkle, or life? The water supply of cities? Croton water? Ridgewood?] 31. Water from springs and wells always contains more or less foreign matter of mineral origin. This imparts to the drink its pleasant taste--the sparkle, or "life," coming from the gases absorbed by the water during its passage under ground. The ordinary supply of cities is from some pure stream or pond conveyed from a distance through pipes, the limpid fluid containing generally only a small amount of impurity. Croton water, the supply of New York City, is very pure, and contains only four and a half grains to a gallon: the Ridgewood water of Brooklyn holds even less foreign matter. [Sidenote: 32. Impurities in drinking-water? Mineral springs?] 32. Drinking-water may contain as large a proportion as sixty to seventy grains per gallon of impurity, but a much larger quantity renders it unwholesome. The mineral spring waters, used popularly as medicines, are highly charged with mineral substances. Some of them, such as {75} the waters at Saratoga, contain three hundred grains and more to the gallon. [Sidenote: 33. What is stated of the action of water upon lead?] 33. ACTION OF WATER UPON LEAD.--The danger of using water that has been in contact with certain metals is well known. Lead is one of the most readily soluble, and probably the most poisonous of these substances in common use. When pure water and an untarnished surface of lead come in contact, the water gradually corrodes the metal, and soon holds an appreciable quantity of it in solution. When this takes place the water becomes highly injurious: the purer the water, and the more recent the use of the metal, the greater will be the danger. [Sidenote: 34. Lead in pipes and other things? Advice? What takes place after the articles of lead have been used much? What is wise?] 34. In cities, lead pipes are commonly used to convey water through the houses; lead being also used in the construction of roofs, cisterns, and vessels for keeping water and other liquids. After the articles of lead have been in use several months, the danger of lead-poisoning diminishes. An insoluble coating of the sulphate of lead forms upon the exposed surface, thus protecting it from further corrosion. It is, however, a wise precaution, at all times to reject the water or other fluid that has been in contact with leaden vessels over night, or for a number of hours. Allow the water in pipes to run freely before using. [Sidenote: 35. Coffee as an article of diet? Of what does it consist? How does the water affect the coffee? The peculiar stimulant? How does it affect most persons?] 35. COFFEE.--This is an important addition to diet, and if moderately used is beneficial to persons of adult age. As commonly employed, it consists of an infusion in boiling water of the roasted and ground berry. The water extracts certain flavoring and coloring matters, but that which gives it its peculiar stimulant qualities is the alkaloid _caffein_. With most persons its action is that of a gentle stimulant, without any injurious reaction. It produces a restful feeling after exhausting efforts of mind or {76} body; it tranquilizes, but does not disqualify for labor; and hence it is highly esteemed by persons of literary pursuits. [Sidenote: 36. Another property of coffee? Miners of Belgium? The Caravans? Among armies? Taken with meals?] 36. Another property of coffee is, that it diminishes the waste of the tissues, and consequently permits the performance of excessive labor upon an economical and inadequate diet. This has been tested among the miners of Belgium. Their allowance of solid food was below that found necessary in prisons and elsewhere; but, with the addition of about four pints of coffee daily, they were enabled to undergo severe labor without reducing their muscular strength. The caravans which traverse the deserts are supported by coffee during long journeys and lengthened privation of food. Among armies it is indispensable in supplementing their imperfect rations, and in relieving the sense of fatigue after great exposure and long marches. When taken with meals, coffee is also thought to promote digestion. [Sidenote: 37. Effects of tea-drinking? Peculiar principle? The tea beverage, how made? Black and green tea? Excessive use of tea or coffee?] 37. TEA.--The effects of tea-drinking are very similar to those of coffee, and are due to a peculiar principle called _thein_. This principle is probably the same as that found in coffee, _caffein_, since the chemical composition of both is precisely alike. Tea, as a beverage, is made from the dried leaves of the plant by the addition of hot water; if the tea is boiled, the oil which gives it its agreeable flavor is driven off with the steam. There are two kinds of tea--the black and the green: the latter is sometimes injurious, producing wakefulness and other nervous symptoms. The excessive use of either coffee or tea will cause wakefulness. [Sidenote: 38. Experiments made during Kane's expedition?] 38. During Dr. Kane's expedition in the Arctic regions, the effects of these articles were compared. "After {77} repeated trials, the men took most kindly to coffee in the morning and tea in the evening. The coffee seemed to continue its influence throughout the day, and they seemed to grow hungry less rapidly than after drinking tea, while tea soothed them after a day's hard labor, and the better enabled them to sleep. They both operated upon fatigued men like a charm, and their superiority over alcoholic stimulants was very decided." [Sidenote: 39. State what is said of chocolate.] 39. Chocolate is made from the seeds of the cocoa-tree, a native of tropical America. Its effects resemble somewhat those of tea and coffee, but it is very rich in nutriment. Linnæus, the botanist, was so fond of this beverage, that he gave to the cocoa-tree the name, _Theobroma_--"the Food of the Gods." Its active principle is _theobromin_. [Sidenote: 40. Use of alcoholic drinks, how general? The rule given?] 40. ALCOHOL.--The list of beverages that are consumed for the sake of the alcohol they contain is a very long one. Their use is almost universally prevalent, every civilized nation, and nearly every barbarous one, having its favorite alcoholic drink; and, as a general rule, the nations which stand the highest in civilization have the greatest varieties of these beverages,--at the same time using them the most intelligently and wisely. [Sidenote: 41. The beverages produced by fermentation? The ardent spirits? Grains and fruits employed? Long use of wine? Of distilled liquors?] 41. The wines and malt liquors that contain a small amount of alcohol are produced by fermentation. The beverages that hold a large proportion of alcohol, the "ardent spirits," are made by distillation. Enormous quantities of grains and fruits are thus yearly diverted from their proper uses as food; some of these being corn, wheat, rye, barley, potatoes, and rice; also the grape, apple, pear, peach, sugar-cane, cherry, fig, and orange. Wine, the fermented juice of the grape, has been in use from time immemorial, while the introduction of distilled liquors dates from a comparatively recent period. {78} [Sidenote: 42. Describe the action of alcohol upon the human system? Experience of Dr. Hayes and others?] 42. What is the physiological action of alcohol? Its first and most evident action is stimulation: this effect is transient, and is followed by a variable degree of depression. At first it sharpens the appetite and quickens digestion, but its habitual use impairs both. This stimulation is efficient in giving the system an artificial strength during some temporary derangement, and in enabling the endurance of unusual fatigue or exposure. The experience of Dr. Hayes, and other explorers of the polar regions, is that alcohol does not enable the body to resist the influence of cold, but, on the contrary, is always injurious. [Sidenote: 43. Another property of alcohol? How do we explain the restorative influence of wines and liquors?] 43. Another property it has in common with tea and coffee. It supports the powers of life, economizes food, and retards the waste of tissues; in other words, it "banks the fires," and prevents their burning wastefully. On this principle we explain the restorative influence of wines or liquors during exhausting diseases, in convalescence, and after excessive labors of mind or body. [Sidenote: 44. Alcohol, a poison? Moderate stimulants? Prevailing opinion? Hence?] 44. Pure alcohol, or an excessive quantity of ardent spirits, is an undoubted poison, and has been frequently known to produce fatal results. Stimulants in moderate quantities have been thought to increase strength, and in this view they have been called "alcoholic foods." This is not now conceded by scientific men. The prevailing opinion is, that they serve no useful purpose as an article of diet, and that their beneficial influence is limited to cases where the system is enfeebled, where some unnatural demand is made upon the vital powers, or where the supply of food is insufficient. Hence, while alcohol has not the power to build up, it may obstruct the process of pulling down. {79} QUESTIONS FOR TOPICAL REVIEW. PAGE 1. How is the necessity for food shown? 64 2. To what process of waste and repair is the body constantly subjected? 64 3. How do you account for the sensations of hunger and thirst? 65 4. What further can you state having relation to the subject? 65 5. What can you state in regard to the quantity of food required for the support of life? 65, 66 6. What circumstances change the needs of persons, old and young, as regards food and drink? 65, 67 7. What becomes of all the food and drink we consume? 66 8. What further can you state in relation to the process of renovation through which the body passes? 66 9. What can you state of the habits of nations in respect to diet? 66, 67, 69 10. What in relation to the selection of articles for food? 67 11. What as respects the necessity for changing or varying the diet? 67 12. What has been proved as regards animal food? 67 13. Of what importance is milk as an article of food? 67, 68 14. What are the constituents of milk? 68 15. What can you state of eggs as an article of food? 68 16. Of the meats, so called, as an article of food? 68, 69 17. What effect does cold have upon meats? 69 18. In what other way may beef and pork be preserved? 69 19. What can you state of salted meat as food, and of its continued use? 69 20. What change does meat undergo in the cooking? 70, 71 21. What directions are given for boiling meat? 70 22. What for roasting, and with what results? 70, 71 23. What is said about the frying of meats? 71 24. Give the statement in relation to trichina. 71 25. State what is said in relation to fish. 71 26. What is stated of the usefulness and other properties of the products of the vegetable kingdom? 71, 72 27. What further is said of vegetable food? 71, 72 28. Why is bread made of wheat flour so important as an article of food? 72 29. State whatever else you can in relation to bread. 72, 73 30. Give the statement respecting the potato. 73 31. What is stated of fruits, the use of them, their nutritious qualities, etc.? 73, 74 32. How general is the existence of perfectly pure water? 74 33. What is stated in relation to drinking water? 74, 75 34. How does the action of water upon lead affect lead? 75 35. What further can you state on the subject? 75 36. What properties has coffee as an article of diet? 75, 76 37. In what circumstances has coffee been found peculiarly beneficial? 76 38. What comparison is made between coffee, tea, and chocolate? 76 39. How are the wines, and malt and other alcoholic beverages produced? 77 40. What articles are employed in their production? 77 41. Describe the physiological action of alcohol. 78 42. What comparison is made between tea, coffee, and alcohol? 78 43. What can you state of alcohol, as a poison, a stimulant, and article of diet? 78 44. What, then, can be said of alcohol as a recommendation? 78 * * * * * {80} CHAPTER VI. DIGESTION. _The Principal Processes of Nutrition--The General Plan of Digestion--Mastication--The Teeth--Preservation of the Teeth--Insalivation--The Stomach and the Gastric Juice--The Movements of the Stomach--Gastric Digestion--The Intestines--The Bile and Pancreatic Juice--Intestinal Digestion--Absorption by means of Blood-vessels and Lacteals--The Lymphatic or Absorbent System--The Lymph--Conditions which affect Digestion--The Quality, Quantity, and Temperature of the Food--The Influence of Exercise and Sleep._ [Sidenote: 1. Design of food? How accomplished?] 1. NUTRITION.--The great design of food is to give _nutriment_ or nourishment to the body. But this is not accomplished directly, as the food must first pass through certain preparatory changes, as follows: (1), _Digestion_, by which the food is reduced to a soluble condition; (2), _Absorption_, by which, when digested, it is imbibed into the blood; (3), _Circulation_, which carries the enriched blood to the various parts of the system; and (4), _Assimilation_, by which each tissue derives from the blood the materials necessary for its support. [Sidenote: 2. Sustaining power of food? Simile of the engine? Operation in the human body?] 2. By these means the sustaining power of food is gradually developed and employed, and the vital machinery kept in working order, somewhat after the manner of the steam-engine. To operate the latter, the force imprisoned within the coal and water is set free and converted into motion by the combustion of the fuel and the vaporization of the water. It will be seen, however, when we come to study these operations in the human body, that they are conducted silently and harmoniously, with marvellous delicacy and completeness, and without that friction, and {81} consequent loss of power, which attend the working of the most perfect machinery of man's invention. [Sidenote: 3. Change of food in digestion? Process of digestion? Describe the alimentary canal.] 3. GENERAL PLAN OF DIGESTION.--The great change which food undergoes in digestion is essentially a reforming process, reducing articles of diet, which are at first more or less solid, crude, and coarse, to a liquid and finely comminuted condition, suitable for absorption into the blood. The entire process of digestion takes place in what is called the alimentary canal, a narrow, tortuous tube, about thirty feet in its entire length. This canal begins in the mouth, extends thence downward through the gullet to the stomach (a receptacle in which the principal work of digestion is performed), and thence onward through the small and large intestines. [Illustration: FIG. 16.--SECTION OF THE TRUNK SHOWING THE CAVITIES OF THE CHEST AND ABDOMEN. A, Cavity of Chest; B, Diaphragm; C, Abdomen; D, E, Spinal Column.] [Sidenote: 4. Situation of the stomach and intestines? Action of the food? Mechanical action? Chemical?] 4. The stomach and intestines are situated in the cavity of the abdomen (Fig. 16, C, and Fig. 22), and occupy about two-thirds of its space. The action to which the food is subjected in these organs is of two kinds--mechanical and chemical. By the former it is crushed, agitated, and carried onward from one point to another; by the latter it is changed in form through the solvent power of the various digestive juices. {82} [Sidenote: 5. Describe the process of mastication? How many and what movements?] 5. MASTICATION.--As soon as solid food is taken into the mouth, it undergoes mastication, or chewing. It is caught between the opposite surfaces of the teeth, and by them is cut and crushed into very small fragments. In the movements of chewing, the lower jaw plays the chief part; the upper jaw, having almost no motion, acts simply as a point of resistance, to meet the action of the former. These movements of the lower jaw are of three sorts: a vertical or cutting, a lateral or grinding, and a _to-and-fro_ or gnawing motion. [Illustration: FIG. 17.--SECTION OF A TOOTH. _a_, Enamel; _b_, Cavity; _c c_, Roots; _d_, Body of the Tooth.] [Sidenote: 6. Composition of the teeth? Enamel of the teeth? Interior of teeth?] 6. The teeth are composed of a bone-like material, and are held in place by roots running deeply into the jaw. The exposed portion, or "crown," is protected by a thin layer of enamel (Fig. 17, _a_), the hardest substance in the body, and, like flint, is capable of striking fire with steel. In the interior of each tooth is a cavity, containing blood-vessels and a nerve, which enter it through a minute opening at the point of the root (Fig. 19). [Sidenote: 7. The milk teeth? The permanent teeth?] 7. There are two sets of teeth; first, those belonging to the earlier years of childhood, called the milk teeth, which are twenty in number and small. At six or eight years of age, when the jaw expands, and when the growing body requires a more powerful and numerous set, the roots of {83} the milk teeth are absorbed, and the latter are "shed," or fall out, one after another (Fig. 18), to make room for the permanent set. [Illustration: FIG. 18.--SECTION OF THE JAWS. 1' 2' 3' 4' 5', The Milk Teeth; 1" to 8", The Germs of the Permanent Set.] [Sidenote: 8, 9. Number of teeth? How distributed?] 8. There are thirty-two teeth in the permanent set, as many being in one jaw as the other. Each half-jaw has eight teeth, similarly shaped and arranged in the same order: thus, two incisors, one canine, two bicuspids, and three molars. The front teeth are small, sharp, and chisel-edged, and are well adapted for cutting purposes; hence their name incisors. The canines stand next, one on each side of the jaw; these receive their name from their resemblance to the long, pointed tusks of the dog (Fig. 19). {84} [Illustration: FIG. 19.--SECTION OF THE JAWS--RIGHT SIDE. V, A, N, Veins, Arteries, and Nerves of the Teeth. The root of one tooth in each jaw is cut vertically to show the cavity and the blood-vessels, etc., within it. 1 to 8, Permanent Teeth.] 9. The bicuspids, next in order, are larger and have a broader crown than the former; while behind them are the molars, the largest and most powerful of the entire set. These large back teeth, or "grinders," present a broad, rough surface, suitable for holding and crushing the food. The third molar, or "wisdom tooth," is the last to be cut, and does not appear until about the twenty-first year. {85} The order of arrangement of the teeth is indicated by the following dental formula:-- [Illustration] [Sidenote: 10. Different forms of teeth? Human teeth? The inference?] 10. It is interesting, at this point, to notice the different forms of teeth in different animals, and observe how admirably their teeth are suited to the respective kinds of food upon which they subsist. In the _carnivora_, or flesh-feeders, the teeth are sharp and pointed, enabling them both to seize their prey, and tear it in pieces; while the _herbivora_, or vegetable-feeders, have broad, blunt teeth, with rough crowns, suitable for grinding the tough grasses and grains upon which they feed. Human teeth partake of both forms; some of them are sharp, and others are blunt; they are therefore well adapted for the mastication of both flesh and vegetables. Hence we argue that, although man may live exclusively upon either vegetable or animal food, he should, when possible, choose a diet made up of both varieties. [Sidenote: 11. Cleaning of teeth? Effects of not cleaning?] 11. PRESERVATION OF THE TEETH.--In order that the teeth shall remain in a sound and serviceable condition, some care is of course requisite. In the first place, they require frequent cleansing; for every time we take food, some particles of it remain in the mouth; and these, on account of the heat and moisture present, soon begin to putrefy. This not only renders the breath very offensive, but promotes decay of the teeth. {86} [Sidenote: 12. Effects upon the saliva? Formation of tartar? How prevented? How destroyed?] 12. The saliva, or moisture of the mouth, undergoes a putrefactive change, and becomes the fertile soil in which a certain minute fungus has its growth. This fluid, too, if allowed to dry in the mouth, collects upon the teeth in the form of an unsightly, yellow concretion, called tartar. To prevent this formation, and to remove other offensive substances, the teeth should be frequently cleaned with water, applied by means of a soft tooth-brush. The destruction of the tartar fungus is best effected by the use of a weak solution of carbolic acid. [Sidenote: 13. Destruction of the enamel? How guarded against?] 13. Again, it should be borne in mind that the enamel, Nature's protection for the teeth, when once destroyed, is not formed anew; and the body of the tooth thus exposed, is liable to rapid decay. On this account, certain articles are to be guarded against; such as sharply acid substances that corrode the enamel, and hard substances that break or scratch it--as gritty tooth powders, metal tooth picks, and the shells of hard nuts. Sudden alternations from heat to cold, when eating or drinking, also tend to crack the enamel. [Sidenote: 14. Mixing of food with the saliva? What is the saliva? How secreted? The salivary glands?] 14. INSALIVATION.--When the morsel of food is cut and ground by the teeth, it is at the same time also intimately mixed with the saliva, or fluids of the mouth. This constitutes the second step of digestion, and is called insalivation. The saliva, the first of the digestive solvents, is a colorless, watery, and frothy fluid. It is secreted (_i. e._ separated from the blood) partly by the mucous membrane which lines the mouth; but chiefly by the salivary glands, of which there are three pairs situated near the mouth. [Sidenote: 15. The flow of saliva? The thought of food? Anxiety and grief? Animals fed upon dry and coarse food?] {87} 15. These glands consist of clusters of very small pouches, around which a delicate network of blood-vessels is arranged: they empty into the mouth by means of little tubes, or ducts. The flow from these glands is at all times sufficient to maintain a soft and moist condition of the tongue and mouth; but when they are excited by the presence and taste of food, they pour forth the saliva more freely. Even the mere thought of food will at times cause the saliva to flow, as when the appetite is stimulated by the sight or smell of some savory article; so that the common expression is correct that "the mouth waters" for the favorite articles of food. Anxiety and grief prevent its flow, and cause "the tongue to cleave to the roof of the mouth." In the horse and other animals, that feed upon dry and coarse fodder, and require an abundant supply of saliva, we find large salivary glands, as well as powerful muscles of mastication. [Illustration: FIG. 20.--STRUCTURE OF A SALIVARY GLAND.] [Illustration: FIG. 21.--THE HEAD OF A HORSE, showing the large salivary gland (_a_), its duct (_b_), the muscles of mastication (_c_, _d_, _e_, _f_, and _g_).] [Sidenote: 16. Importance of the process? The first place? The second? The third?] 16. The mingling of the saliva with the food seems a simple process, but it is one that plays an important part {88} in digestion. In the first place, it facilitates the motions of mastication, by moistening the food and lubricating the various organs of the mouth. Secondly, it prepares the way for other digestive acts: by the action of the teeth, the saliva is forced into the solid food, softens the harder substances, and assists in converting the whole morsel into a semi-solid, pulpy mass, that can be easily swallowed, and readily permeated by other digestive fluids. The saliva also, by dissolving certain substances, as sugar and salt, develops the peculiar taste of each; whereas, if the tongue be dry and coated, they are tasteless. Hence, if substances are insoluble, they are devoid of taste. [Sidenote: 17. Its final importance? Starch? How effected? Ptyalin?] 17. Finally, the saliva has the property of acting chemically upon the food. As we have before stated (Chap. IV.), starch, as starch, cannot enter the tissues of the body; but, in order to become nutriment, must first be changed to grape sugar. This change is, in part, effected by the saliva, and takes place almost instantly, whenever it comes in contact with cooked starch. This important function is due to an organic ingredient of the saliva called _ptyalin_. This substance has been extracted from the saliva by the chemist, and has been found, by experiment, to convert into sugar two thousand times its own weight of starch. [Sidenote: 18. Each of the processes? Why is a knowledge of the digestive functions important? How shown?] 18. IMPORTANCE OF MASTICATION AND INSALIVATION.--Each of these processes complements the other, and makes the entire work available; for, by their joint action, they prepare the food in the best possible manner for further digestive changes. The knowledge of these preliminary functions will appear the more important, when we reflect that they are the only ones which we can regulate by the will. For, as soon as the act of swallowing begins, the food not only passes out of sight, but beyond {89} control; and the subsequent acts of digestion are consequently involuntary and unconsciously performed. [Sidenote: 19. Rapid eating? Describe the process and effects.] 19. It is generally known that rapid eating interferes with digestion. How does this occur? In the first place, in rapid eating, the flow of the saliva is insufficient to moisten the solid parts of the food, so that they remain too hard and dry to be easily swallowed. This leads to the free and frequent use of water, or some other beverage, at meals, to "wash down" the food,--a most pernicious practice. For these fluids, not only cannot take the place of the natural digestive juices, but, on the contrary, dilute and weaken them. [Sidenote: 20. Loss of taste? Another effect of rapid eating? Mistakes?] 20. Secondly, the saliva being largely the medium of the sense of taste, the natural flavors of the food are not developed, and consequently it appears comparatively insipid. Hence the desire for high-seasoned food, and pungent sauces, that both deprave the taste and over excite the digestive organs. Rapid eating also permits the entrance of injurious substances which may escape detection by the taste, and be unconsciously received into the system. In some instances, the most acrid and poisonous substances have frequently been swallowed "by mistake," before the sense of taste could act, and demand their rejection. [Sidenote: 21. Effect of imperfectly broken food in the stomach? Dyspepsia? Overeating?] 21. Thirdly, the food, being imperfectly broken up by the teeth, is hurried onward to the stomach, to be by it more thoroughly divided. But the task thus imposed upon the stomach, it is not at all adapted to perform; so that the crude masses of food remain a heavy burden within the stomach, and a source of distress to that organ, retarding the performance of its legitimate duty. Hence persons who habitually eat too rapidly, frequently fall victims to dyspepsia. Rapid eating also conduces to overeating. The food is introduced so rapidly, that the system has not {90} time to recognize that its real wants are met, and that its losses have been made good; and hence the appetite continues, although more nutriment has been swallowed than the system requires, or can healthfully appropriate. [Illustration: FIG. 22.--SECTION OF CHEST AND ABDOMEN. A, Heart. B, The Lungs. C, Stomach. D, The Liver. E, Large Intestine. G, Small Intestine.] [Sidenote: 22. Gullet? Describe the stomach and its location. Effects of gormandizing?] 22. THE STOMACH.--As soon as each separate portion of food is masticated and insalivated, it is swallowed; that is, it is propelled downward to the stomach, through a narrow muscular tube about nine inches in length, called the _oesophagus_, or gullet (Fig. 23). The stomach is the only large expansion of the digestive canal, and is the most important organ of digestion. It is a hollow, pear-shaped pouch, having a capacity of three pints, in the adult. Its walls are thin and yielding, and may become unnaturally distended, as in the case of those who subsist on a bulky, innutritious diet, and of those who habitually gormandize. [Sidenote: 23. Heart-orifice? Gatekeeper? Coins, etc.? Indication of the soft and yielding texture of the stomach?] 23. The stomach has also two openings; that by which food enters, being situated near the heart, is called the _cardiac_, or heart orifice; the other is the _pylorus_, or "gatekeeper," which guards the entrance to the intestines, {91} and, under ordinary circumstances, permits only such matters to pass it as have first been properly acted upon in the stomach. Coins, buttons, and the like are, however, readily allowed to pass, because they can be of no use if retained. The soft and yielding texture of this organ--the stomach--indicates that it is not designed to crush and comminute solid articles of food. [Illustration: FIG. 23.--THE ORGANS OF DIGESTION. O, Oesophagus. S, Stomach. L, Liver. M, Pylorus. C, Large Intestines. P, Pancreas. I, Small Intestines. N, Spleen. G, Gall-bladder. ] [Sidenote: 24. What is meant by the gastric juice?] 24. THE GASTRIC JUICE.--We have seen how the presence of food in the mouth excites the salivary glands, causing the saliva quickly to flow. In the same manner, when food reaches the stomach, its inner lining, the mucous membrane, is at once excited to activity. (At first its surface, which while the stomach is empty presents a pale pink hue, turns to a bright red color, for the minute blood-vessels which course through it, are filled with blood. Presently a clear, colorless, and acid fluid exudes, drop by drop, from its numerous minute glands or "tubules," until finally the surface is moistened in every part, and the fluid begins to mingle with the food. This fluid is termed the gastric juice. {92} [Sidenote: 25. What is the office of the gastric juice? Acidity of the gastric juice? Quantity of gastric juice used? What becomes of it?] 25. The gastric juice is the proper solvent of certain articles of food, especially those belonging to the albuminoid class. This solvent power is due to its peculiar ingredient, _pepsin_; in digestion, this substance acts like a ferment; that is, it induces changes in the food simply by its presence, but does not itself undergo change. The acidity of the gastric juice, which is due to _lactic acid_, is not accidental; for we find that the pepsin cannot act in an alkaline solution--that is, one which is not acid or neutral. The quantity of gastric juice secreted daily is very large, probably not less than three or four pints at each meal. Though this fluid is at once used in the reduction of the food, it is not lost; since it is soon re-absorbed by the stomach, together with those parts of the food which it has digested and holds in solution. [Sidenote: 26. Muscular coat of the stomach? Expansion and contraction of its fibres? Action of the fibres?] 26. MOVEMENTS OF THE STOMACH.--The inner coating of the stomach is the mucous membrane, which, as we have seen, furnishes the gastric juice. Next to this coating lies another, called the muscular coat, composed of involuntary muscular fibres, some of which run circularly, and others in a longitudinal direction. These expand to accommodate the food as it is introduced, and contract as it passes out. In addition, these fibres are in continual motion while food remains in the stomach, and they act in such manner that the contents are gently turned round from side to side, or from one end of it to the other. [Sidenote: 27. Peristaltic movements? What is said of our consciousness of and power over these movements? Describe the movements of the pylorus.] 27. By these incessant movements of the stomach, called the _peristaltic_ movements, the gastric juice comes in contact with all parts of the food. We are, however, not conscious that these movements take place, nor have we the power to control them. When such portions of the food as are sufficiently digested approach the pylorus, it {93} expands to allow them to pass out, and it closes again to confine the residue for further preparation. [Sidenote: 28. How has the knowledge and the workings of the stomach been ascertained? St. Martin? How else?] 28. The knowledge of these and other interesting and instructive facts has been obtained by actual observation; the workings of the stomach of a living human being have been laid open to view and examined--the result of a remarkable accident. Alexis St. Martin, a Canadian _voyageur_, received a gun-shot wound which laid open his stomach, and which, in healing, left a permanent orifice nearly an inch in diameter. Through this opening the observer could watch the progress of digestion, and experiment with different articles of food. Since that occurrence, artificial openings into the stomach of the inferior animals have been repeatedly made, so that the facts of stomach-digestion are very well ascertained and verified. [Sidenote: 29. What was formerly thought? What do we now know? What else do we now know? Water, salt, and sugar? Absorption?] 29. GASTRIC DIGESTION.--What portions of the food are digested in the stomach? It was formerly thought that all the great changes of digestion were wrought here, but later investigation has taught us better. We now know that the first change in digestion takes place in the mouth, in the partial conversion of starch into sugar. We also know that, of the three organic food principles (considered in Chapter IV.) two--the fats and the sugars--are but slightly affected by the stomach; but that its action is confined to that third and very important class, from which the tissues are renewed, the albuminoids. A few articles need no preparation before entering the system, as water, salt, and grape-sugar. These are rapidly taken up by the blood-vessels of the stomach, which everywhere underlie its mucous membrane in an intricate and most delicate network. In this way the function of absorption begins. [Sidenote: 30. Albuminose? The process? Chyme?] 30. The albuminoid substances are speedily attacked and {94} digested by the gastric juice. From whatever source they are derived, vegetable or animal, they are all transformed into the same digestive product, called _albuminose_. This is very soluble in water, and is readily absorbed by the blood-vessels of the stomach. After a longer or shorter time, varying from one to five hours, according to the individual and the quantity and quality of his food, the stomach will be found empty. Not only has the digested food passed out, but also those substances which the stomach could not digest or absorb have passed little by little through the pylorus, to undergo further action in the intestines. At the time of its exit, the digested food is of a pulpy consistence, and dark color, and is then known as the _chyme_. [Sidenote: 31. What are the intestines? The small intestines? The large intestines? Their structure?] 31. THE INTESTINES.--The intestines, or "bowels," are continuous with the stomach, and consist of a fleshy tube, or canal, twenty-five feet in length. The small intestine, whose diameter is about one inch and a half, is twenty feet long and very tortuous. The large intestine is much wider than the former, and five feet long (Fig. 23). The general structure of these organs resembles that of the stomach. Like it, they are provided with a mucous membrane, or inner lining, whence flow their digestive juices; and, just outside of this, a muscular coat, which propels the food onward from one point to another. [Sidenote: 32. Peritoneum? The work of digestion?] 32. Moreover, both the intestines and stomach are enveloped in the folds of the same outer tunic or membrane, called the _peritoneum_. This is so smooth and so well lubricated, that the intestines have the utmost freedom of motion. In the small intestines, the work of digestion is completed, the large intestine receiving from them the indigestible residue of the food, and in time expelling it from the body. [Sidenote: 33. The presence of food in the intestines? Bile?] 33. INTESTINAL DIGESTION.--As soon as the food passes the pylorus and begins to accumulate in the upper {95} part of the intestines, it excites the flow of a new digestive fluid, which enters through a small tube, or _duct_, about three inches below the stomach. It is formed by the union of two distinct fluids--the _bile_ and the _pancreatic_ juice. The bile is secreted by the liver, which is the largest gland of the body, and is situated on the right side and upper part of the abdomen (Fig. 22). The bile is constantly formed, but it flows most rapidly during digestion. During the intervals of digestion it is stored in the _gall-bladder_, a small membranous bag attached to the under side of the liver. This fluid is of a greenish-yellow color, having a peculiar smell, and a very bitter taste. [Sidenote: 34. The pancreatic juice? The joint action of these fluids?] 34. The pancreatic juice is the product of a gland called the _pancreas_, situated behind the stomach. This fluid is colorless, viscid, and without odor. Like the digestive juices previously described, it owes its solvent power to its peculiar ferment principle, called _pancreatin_. By the joint action of these fluids, the fatty parts of the food are prepared for absorption. By previous steps of digestion the fats are merely separated from the other components of the food; but here, within the intestines, they are reduced to a state of minute division, or _emulsion_, resembling the condition of butter in milk, before it has been churned. There results from this action a white and milky fluid, termed the _chyle_, which holds in solution the digestible portions of the food, and is spread over the extensive absorbent surface of the small intestines. [Sidenote: 35. The mucous membrane? Experiments on inferior animals?] 35. The mucous membrane of the intestines, also, secretes or produces, a digestive fluid by means of numerous "follicles," or minute glands; this is called the intestinal juice. From experiments on the inferior animals, it has been ascertained that this fluid exerts a solvent influence over each of the three organic food principles, and in this way may supplement and complete the action of the {96} fluids previously mentioned, viz.:--of the saliva in converting starch into sugar, of the gastric juice in digesting the albuminoids, and of the pancreatic juice and bile in emulsifying the fats. [Sidenote: 36, 37. How much thus far has been done with the food? The next process? Give the first way.] 36. ABSORPTION.--With the elaboration of the chyle, the work of digestion is completed; but, in a certain sense, the food is yet outside of the body; that is, the blood is not yet enriched by it, and it is not in a position to nourish the tissues. The process by which the liquefied food passes out of the alimentary canal into the blood is called absorption. This is accomplished in two ways; first, by the _blood-vessels_. We have seen how the inner membrane of the stomach is underlaid by a tracery of minute and numerous vessels, and how some portions of the food are by them absorbed. The supply of blood-vessels to the intestines is even greater; particularly to the small intestines, where the work of absorption is more actively carried on. 37. The absorbing surface of the small intestines, if considered as a plane surface, amounts to not less than half a square yard. Besides, the mucous membrane is formed in folds with an immense number of thread-like prolongations, called _villi_, which indefinitely multiply its absorbing capacity. These minute processes, the villi, give the surface the appearance and smoothness of velvet; and during digestion, they dip into the canal, and, by means of their blood-vessels, absorb its fluid contents, just as the _spongioles_ which terminate the rootlets of plants, imbibe moisture from the surrounding soil. [Sidenote: 38. How is absorption effected in another way? Describe it. Name of the lacteals? Thoracic duct?] 38. Secondly, absorption is also effected by the _lacteals_, a set of vessels peculiar to the small intestines. These have their beginnings in the little villi just mentioned, side by side with the blood-vessels. These two sets of absorbents run in different courses, but their destination is the same, {97} which is the right side of the heart. The lacteals receive their name from their milky-white appearance. After a meal containing a portion of fat, they are then distended with chyle, which they are specially adapted to receive: at other times they are hardly discernible. The lacteals all unite to form one tube, the _thoracic duct_, which passes upward through the _thorax_, or chest, and empties into a large vein, situated just beneath the left collar-bone. [Illustration: FIG. 24.--THE LACTEALS. A, Small Intestine. B, Lacteals. C, Thoracic Duct. D, Absorbents. E, Blood-vessel. ] [Sidenote: 39. The absorbents? Lymph? What further of the lymph?] 39. THE ABSORBENTS.--The lacteals belong to a class of vessels known as absorbents, or lymphatics, which ramify in nearly all parts of the body, except the brain and spinal cord. The fluid which circulates through the lymphatics of the limbs, and all the organs not concerned in digestion, is called _lymph_. This fluid is clear and colorless, like water, and thus differs from the milky chyle which the lacteals carry after digestion: it consists chiefly of the watery part of the blood, which was not required by the tissues, and is returned to the blood by the absorbents or lymphatics. [Sidenote: 40. What can you state as to the time required for digestion?] 40. CIRCUMSTANCES AFFECTING DIGESTION.--What length of time is required for the digestion of food? From observations made, in the case of St. Martin, the Canadian {98} already referred to, it has been ascertained that, at the end of two hours after a meal, the stomach is ordinarily empty. How much time is needed to complete the digestion of food, within the small intestines, is not certain; but, from what we have learned respecting their functions, it must be evident that it largely depends upon the amount of starch and fat which the food contains. [Sidenote: 41. Circumstances affecting duration of digestion? Fresh food?] 41. In addition to the preparations which the food undergoes in cooking, which we have already considered, many circumstances affect the duration of digestion; such as the quality, quantity, and temperature of the food; the condition of the mind and body; sleep, exercise, and habit. Fresh food, except new bread and the flesh of animals recently slain, is more rapidly digested than that which is stale; and animal food more rapidly than that from the vegetable kingdom. [Sidenote: 42. Food in concentrated form? A large quantity of food? Experiment on the dog? Ice-water? Variety of articles?] 42. Food should not be taken in too concentrated a form, the action of the stomach being favored when it is somewhat bulky; but a large quantity in the stomach often retards digestion. If the white of one egg be given to a dog, it will be digested in an hour, but if the white of eight eggs be given it will not disappear in four hours. A wineglassful of ice-water causes the temperature of the stomach to fall thirty degrees; and it requires a half-hour before it will recover its natural warmth--about a hundred degrees--at which the operations of digestion are best conducted. A variety of articles, if not too large in amount, is more easily disposed of than a meal made of a single article; although a single indigestible article may interfere with the reduction of articles that are easily digested. [Sidenote: 43. Strong emotion? The tongue of the patient?] 43. Strong emotion, whether of excitement or depression, checks digestion, as do also a bad temper, anxiety, long fasting, and bodily fatigue. The majority of these {99} conditions make the mouth dry, that is, they restrain the flow of the saliva; and without doubt they render the stomach dry also, by preventing the flow of the gastric juice. And, as a general rule, we may decide, from a parched and coated tongue, that the condition of the stomach is not very dissimilar, and that it is unfit for the performance of digestive labor. This is one of the points which the physician bears in mind when he examines the tongue of his patient. [Sidenote: 44. Eating between meals? Severe exercise? Sleep after meals?] 44. The practice of eating at short intervals, or "between meals," as it is called, has its disadvantage, as well as rapid eating and over-eating, since it robs the stomach of its needed period of entire rest, and thus overtasks its power. With the exception of infants and the sick, no persons require food more frequently than once in four hours. Severe exercise either directly before or directly after eating retards digestion; a period of repose is most favorable to the proper action of the stomach. The natural inclination to rest after a hearty meal may be indulged, but should not be carried to the extent of sleeping; since in that state the stomach, as well as the brain and the muscles, seeks release from labor. {100} QUESTIONS FOR TOPICAL REVIEW. PAGE 1. What do you understand by nutrition? 80 2. How is the process of nutrition carried on? 80 3. What further can you state on the subject? 80, 81 4. Describe the general plan of digestion. 81 5. How is the process of mastication carried on? 80, 82 6. State what you can in relation to the formation of the teeth. 82, 86 7. What, in relation to their arrangement? 83, 84 8. What, in relation to the process of "shedding?" 82, 83, 84 9. In relation to the different forms of teeth in different animals? 85 10. What causes operate to injure or destroy the teeth? 85, 86 11. What suggestions and directions are given for the preservation of the teeth? 85, 86 12. What do you understand by insalivation? 80, 86 13. How is the process of insalivation carried on? 86, 87, 88 14. Of what importance is the saliva to the process? 87, 88 15. Of what importance are mastication and insalivation? 88, 89 16. Describe the consequences of rapid eating. 89, 90 17. What becomes of the food directly after it has undergone mastication and insalivation? 90 18. Describe the location and formation of the stomach. 90, 91, 92 19. Describe the process by which the gastric juice is formed. 91 20. What are the properties and uses of the gastric juice? 92 21. What are the movements of the stomach, and what their uses? 92, 93 22. What further can you state on the subject? 93 23. What portions of the food are digested in the stomach? 93, 94 24. What are the first changes of digestion? 93 25. Describe the location and formation of the stomach. 94 26. What further can you state in relation to the stomach? 94 27. Describe the process of intestinal digestion. 94, 95, 96 28. What do you understand by absorption? 80, 96 29. How is the process of absorption effected? 96, 97 30. What are the lacteals and of what use are they? 96, 97 31. What length of time is required for the digestion of food? 97, 98 32. What circumstances, of food, affect digestion? 98 33. What circumstances, of emotion, affect digestion? 98, 99 34. What suggestions and directions are given upon the subject of eating and drinking? 98, 99 * * * * * [Illustration: CIRCULATION OF THE BLOOD. [Heart, Lungs, Arteries & Veins.] {101} CHAPTER VII. THE CIRCULATION. _The Blood--Its Plasma and Corpuscles--Coagulation of the Blood--The Uses of the Blood--Transfusion--Change of Color--The Organs of the Circulation--The Heart, Arteries, and Veins--The Cavities and Valves of the Heart--Its Vital Energy--Passage of the Blood through the Heart--The Frequency and Activity of its Movements--The Pulse--The Sphygmograph--The Capillary Blood-vessels--The Rate of the Circulation--Assimilation--Injuries to the Blood-vessels._ [Sidenote: 1. What is required by every living organism? In plants? Insects? Reptiles? Man?] 1. THE BLOOD.--Every living organism of the higher sort, whether animal or vegetable, requires for the maintenance of life and activity, a circulatory fluid, by which nutriment is distributed to all its parts. In plants, this fluid is the sap; in insects, it is a watery and colorless blood; in reptiles and fishes, it is red but cold blood; while in the nobler animals and man, it is the red and warm blood. [Sidenote: 2. Importance and abundance of blood? Dependence of life? Abel? Mosaic law? In what part of the body is blood not found? Quantity of blood in the body?] 2. The blood is the most important, as it is the most abundant, fluid of the body; and upon its presence, under certain definite conditions, life depends. On this account it is frequently, and very properly, termed "the vital fluid." The importance of the blood, as essential to life, was recognized in the earliest writings. In the narration of the death of the murdered Abel, it is written, "the voice of his _blood_ crieth from the ground." In the Mosaic law, proclaimed over thirty centuries ago, the Israelites were forbidden to eat food that contained blood, for the reason that "the life of the flesh is in the blood." With the exception of a few tissues, such as the hair, the nails, and the _cornea_ of the eye, blood everywhere pervades the body, as may be proven by puncturing any part with a {102} needle. The total quantity of blood in the body is estimated at about one-eighth of its weight, or eighteen pounds. [Sidenote: 3. Color of blood? Its consistence? Odor?] 3. The color of the blood, in man and the higher animals, as is well known, is red; but it varies from a bright scarlet to a dark purple, according to the part whence it is taken. "Blood is thicker than water," as the adage truly states, and has a glutinous quality. It has a faint odor, resembling that peculiar to the animal from which it is taken. [Sidenote: 4. What is stated of the blood as viewed under the microscope?] 4. When examined under the microscope, the blood no longer appears a simple fluid, and its color is no longer red. It is then seen to be made up of two distinct parts: first, a clear, colorless fluid, called the _plasma_; and secondly, of a multitude of minute solid bodies, or corpuscles, that float in the watery plasma. The plasma, or nutritive liquid, is composed of water richly charged with materials derived from the food, viz., albumen, which gives it smoothness and swift motion; fibrin; certain fats; traces of sugar; and various salts. [Illustration: FIG 25.--THE BLOOD CORPUSCLES.] [Sidenote: 5. State what you can of the little bodies called corpuscles.] 5. THE BLOOD CORPUSCLES.--In man, these remarkable "little bodies," as the word _corpuscles_ signifies, are of a yellow color, but by their vast numbers impart a red hue to the blood. They are very small, having a diameter of about 1/3500 of an inch, and being one-fourth of that fraction in thickness; so that if 3,500 of them were placed in line, side by side, they would only extend one inch; or, if {103} piled one above another, it would take at least 14,000 of them to stand an inch high. Although so small in size, they are very regular in form. As seen under the microscope, they are not globular or spherical, but flat, circular, and disc-like, with central depressions on each side, somewhat like a pearl button that has not been perforated. In freshly-drawn blood they show a disposition to arrange themselves in little rolls like coins (Fig. 25). [Illustration: FIG. 26. _a_, Oval Corpuscles of a fowl. _b_, Corpuscles of a frog. _c_, Those of a shark. The five small ones at the upper part of the figure, represent the human corpuscles magnified 400 times.] [Sidenote: 6. The size and shape of corpuscles? Why is the fact important?] 6. The size and shape of the blood corpuscles vary in different animals, so that it is possible to discriminate between those of man and the lower animals (Fig. 26). This is a point of considerable practical importance. For example, it is sometimes desirable to decide in a court of justice the source, whether from man or an inferior animal, of blood stains upon the clothing of an accused person, or upon some deadly weapon. This may be done by a microscopical examination of a minute portion of the dried stain, previously refreshed by means of gum-water. Certain celebrated cases are recorded in which the guilt of criminals has been established, and they have been condemned and punished upon the evidence which science rendered on this single point, the detecting of the human from other blood. [Sidenote: 7. The character of the blood of dead animals? Means of detecting such blood?] 7. The character of the blood of dead, extinct, and even fossil animals, such as the mastodon, has been ascertained by obtaining and examining traces of it which had been shut up, perhaps for ages, in the circulatory canals of bone. A means of detecting blood in minute quantities is found {104} in the spectroscope, the same instrument by which the constitution of the heavenly bodies has been studied. If a solution containing not more than one-thousandth part of a grain of the coloring matter of the corpuscle, be examined, this instrument will detect it. [Sidenote: 8. White corpuscles? Total number of corpuscles in the body?] 8. The corpuscles, just described, are known as the red blood corpuscles. Besides these, and floating along in the same plasma, are the white corpuscles. These are fewer in number, but larger and globular in form. They are colorless, and their motion is less rapid than that of the other variety. The total number of both varieties of these little bodies in the blood is enormous. It is calculated that in a cubic inch of that fluid there are eighty-three millions, and at least five hundred times that number in the whole body. [Sidenote: 9. The blood in its natural condition in the body? Describe the process by which the coagulation of blood takes place?] 9. COAGULATION.--The blood, in its natural condition in the body, remains perfectly fluid; but, within a few minutes after its removal from its proper vessels, whether by accident or design, a change takes place. It begins to coagulate, or assume a semi-solid consistence. If allowed to stand, after several hours it separates into two distinct parts, one of them being a dark red jelly, the coagulum, or clot, which is heavy and sinks; and the other, a clear, straw-colored liquid, called serum, which covers the clot. This change is dependent upon the presence in the blood of fibrin, which possesses the property of solidifying under certain circumstances; one of these circumstances being when the blood is separated from living tissues. The color of the clot is due to the entanglement of the corpuscles with the fibrin. [Sidenote: 10. If coagulation were impossible? How is it in fact?] 10. In this law of the coagulation of the blood is our safeguard against death by hæmorrhage, or against undue loss of blood. If coagulation were impossible, the {105} slightest injury in drawing blood would prove fatal. Whereas now, in vastly the larger proportion of cases, bleeding ceases spontaneously, because the blood, as it coagulates, stops the mouths of the injured blood-vessels. In another class of cases, where larger vessels are cut or torn, it is simply necessary to close them by a temporary pressure; for in a few minutes the clot will form and seal them up. In still more serious cases, where the blood-vessel is of large size, the surgeon is obliged to tie a "ligature" about it, and thus prevent the force of the blood-current from washing away the clots, which, forming within and around the vessel, would close it effectually. [Sidenote: 11. What is worthy of remark? Coagulation of the blood of inferior animals? Of the blood of birds?] 11. It is worthy of remark that this peculiarity is early implanted in the blood, even before birth, and in advance of any existing necessity for it; thus anticipating and guarding against danger. But this is not all. Of most of the inferior animals, which, as compared with man, are quite helpless, the blood coagulates more rapidly, and in the case of the birds, almost instantly. The relative composition of fluid and coagulated blood may be thus represented: _Fluid Blood._ _Coagulated Blood._ Plasma----------Serum---------Serum \ \ --------Fibrin-------- \ \ Corpuscles------Corpuscles-------Clot. [Sidenote: 12. The blood, as a provider and purifier? What uses does the blood subserve? Experiments? Transfusion?] 12. THE USES OF THE BLOOD.--The blood is the great provider and purifier of the body. It both carries new materials to all the tissues, and removes the worn out particles of matter. This is effected by the plasma. It both conveys oxygen and removes carbonic acid. This is done through the corpuscles. Some singular experiments have {106} been tried to illustrate the life-giving power of the blood. An animal that has bled so freely as to be at the point of dying, is promptly brought back to life by an operation called transfusion, by which fresh blood from a living animal is injected into the blood-vessels of his body. [Sidenote: 13. The case of the deaf and feeble dog? Horse? Dead dog?] 13. It is related that a dog, deaf and feeble from age, had hearing and activity restored to him by the introduction into his veins of blood taken from a young dog; and, that a horse, twenty-six years old, having received the blood of four lambs acquired new vigor. And further, that a dog, just dead from an acute disease, was so far revived by transfusion, as to be able to stand and make a few movements. [Sidenote: 14. Transfusion, as a fashionable remedy? What further of transfusion?] 14. Transfusion has been practised upon man. At one time, shortly after Harvey's discovery of the "Circulation of the Blood," it became quite a fashionable remedy, it being thought possible by it to cure all forms of disease, and even to make the old young again. But these claims were soon found extravagant, and many unhappy accidents occurred in its practice; so that being forbidden by government and interdicted by the Pope, it rapidly fell into disuse. At the present time, however, it is sometimes resorted to in extreme cases, when there has been a great and rapid loss of blood; and there are upon record several instances where, other means having failed, life has been restored or prolonged by the operation of transfusion. [Sidenote: 15. The seat of the reviving power of the blood? What further is related?] 15. This reviving power of the blood seems to reside in the corpuscles; for transfusion, when attempted to be performed with the serum alone, has, in every case, proved fruitless. Now, though so much depends upon the blood and its corpuscles, it is a mistake to suppose that in them alone is the seat of life, or that they are, in an exclusive manner, alive. All the organs and parts of the body are mutually dependent one upon the other; and the complete usefulness {107} of the blood, or of any other part, flows out of the harmonious action of all the parts. [Sidenote: 16. Changes in the blood? What further is stated?] 16. CHANGE OF COLOR.--The blood undergoes a variety of changes in its journey through the system. As it visits the different organs it both gives out and takes up materials. In one place it is enriched, in another it is impoverished. By reason of these alterations in its composition, the blood also changes its color. In one part of the body it is bright red, or arterial; in another it is dark blue, or venous. In the former case it is pure and fit for the support of the tissues; in the latter, it is impure and charged with effete materials. (The details of the change from dark to bright will be given in the chapter on Respiration.) [Sidenote: 17. Motion of the blood? What is meant by the circulation of the blood? How confined? Discovery made by Harvey?] 17. CIRCULATION.--The blood is in constant motion during life. From the heart, as a centre, a current is always setting toward the different organs; and from these organs a current is constantly returning to the heart. In this way a ceaseless circular movement is kept up, which is called the Circulation of the Blood. This stream of the vital fluid is confined to certain fixed channels, the blood-vessels. Those branching from the heart are the arteries; those converging to it are the veins. The true course of the blood was unknown before the beginning of the seventeenth century. In 1619 it was discovered by the illustrious William Harvey. Like many other great discoverers, he suffered persecution and loss, but unlike some of them, he was fortunate enough to conquer and survive opposition. He lived long enough to see his discovery universally accepted, and himself honored as a benefactor of mankind. {108} [Illustration: FIG. 27.--THE ORGANS OF CIRCULATION.] {109} [Illustration: FIG. 28.--THE HEART AND LARGE VESSELS. A, Right Ventricle. B, Left Ventricle. C, Right Auricle. D, Left Auricle. E, Aorta. F, Pulmonary Artery.] [Sidenote: 18. Office of the heart? Location of the heart? Its beat? Its shape? Protection to the heart? What else is said in relation to the heart?] 18. THE HEART.--The heart is the central engine of the circulation. In this wonderful little organ, hardly larger than a man's fist, resides that sleepless force by which, during the whole of life, the current of the blood is kept in motion. It is placed in the middle and front part of the chest, inclining to the left side. The heartbeat may be felt and heard between the fifth and sixth ribs, near the breast-bone. The shape of the heart is conical, with the apex or point downward and in front. The base, which is upward, is attached so as to hold it securely in its place, while the apex is freely moveable. In order that loss of power from friction may be obviated, the heart is enclosed between two layers of serous membrane, which forms a kind of sac. This membrane is as smooth as satin, and itself secretes a fluid in sufficient quantities to keep it at all times well lubricated. The lining membrane of the heart, likewise, is extremely delicate and smooth. {110} [Illustration: FIG. 29.--SECTION OF THE HEART. A, Right Ventricle. B, Left Ventricle. C, Right Auricle. D, Left Auricle. E, F, Inlets to the Ventricles. G, Pulmonary Artery. H, Aorta.] [Sidenote: 19. Formation of the heart? Right and left heart?] 19. THE CAVITIES OF THE HEART.--The heart is hollow, and so partitioned as to contain four chambers or cavities; two at the base, known as the _auricles_, from a fancied resemblance to the ear of a dog, and two at the apex or point, called _ventricles_. An auricle and a ventricle on the same side, communicate with each other, but there is no opening from side to side. It is customary to regard the heart as a double organ, and to speak of its division into the right and left heart. For while both halves act together in point of time, each half sustains an entirely distinct portion of the labor of the circulation. Thus, the right heart always carries the dark or venous blood, and the left always circulates the bright or arterial blood. [Sidenote: 20. Capacity of the chambers of the heart? What wise provision is mentioned? The auricles?] 20. If we examine the heart, we at once notice that though its various chambers have about the same capacity, the walls of the ventricles are thicker and stronger than those of the auricles. This is a wise provision, for it is by the powerful action of the former that the blood is forced to the most remote regions of the body. The auricles, on the contrary, need much less power, for they simply discharge their contents into the cavities of the heart near at hand and below them--into the ventricles. {111} [Sidenote: 21. Substance of the heart? Its fibres? Its movements? The advantage of such movements? Action of the heart? Its period of repose?] 21. ACTION OF THE HEART.--The substance of the heart is of a deep red color, and its fibres resemble those of the voluntary muscles by which we move our bodies. But the heart's movements are entirely involuntary. The advantage of this is evident; for if it depended upon us to will each movement, our entire attention would be thus engaged, and we would find no time for study, pleasure, or even sleep. The action of the heart consists in alternate contractions and dilatations. During contraction the walls come forcibly together, and thus drive out the blood. In dilatation, they expand and receive a renewed supply. These movements are called _systole_ and _diastole_. The latter may be called the heart's period of repose; and although it lasts only during two-fifths of a heart-beat, or about a third of a second, yet during the day it amounts to more than nine hours of total rest. [Sidenote: 22. Remarkable property of the tissue of the heart? How shown? How interesting? In cold-blooded animals? Heart of a turtle? Of a frog? Alligator?] 22. A remarkable property of the tissue of the heart is its intense vitality. For while it is more constantly active than any other organ of the body, it is the last to part with its vital energy. This is especially interesting in view of the fact that after life is apparently extinguished, as from drowning, or poisoning by chloroform, there yet lingers a spark of vitality in the heart, which, by continued effort, may be fanned into a flame so as to revivify the whole body. In cold-blooded animals this irritability of the heart is especially remarkable. The heart of a turtle will pulsate, and the blood circulate for a week after its head has been cut off; and the heart will throb regularly many hours after being cut out from the creature's chest. The heart of a frog or serpent, separated entirely from the body, will contract at the end of ten or twelve hours: that of an alligator has been known to beat twenty-eight hours after the death of the animal. {112} [Sidenote: 23. Course of the blood through the heart? Course of heart-currents?] 23. PASSAGE OF THE BLOOD THROUGH THE HEART.--Let us now trace the course of the blood through the several cavities of the heart. In the first place, the venous blood, rendered dark and impure by contact with the changing tissues of the body, returns to the right heart by the veins. It enters and fills the right auricle during its dilatation: the auricle then contracts and fills the right ventricle. Almost instantly, the ventricle contracts forcibly and hurries the blood along the great artery of the lungs, to be purified in those organs. Secondly, having completed the circuit of the lungs, the pure and bright arterial blood enters the left auricle. This now contracts and fills the left ventricle, which cavity, in its turn, contracts and sends the blood forth on its journey again through the system. This general direction from right to left is the uniform and undeviating course of heart-currents. [Sidenote: 24. Openings of the ventricles? How guarded? How do the valves operate? The consequence? Heart-sounds?] 24. The mechanism which enforces and regulates it, is as simple as it is beautiful. Each ventricle has two openings, an inlet and an outlet, each of which is guarded by strong curtains, or valves. These valves open freely to admit the blood entering from the right, but close inflexibly against its return. Thus, when the auricle contracts, the inlet valve opens; but as soon as the ventricle begins to contract, it closes promptly. The contents are then, so to speak, cornered, and have but one avenue of escape, that through the outlet valve into the arteries beyond. As soon as the ventricle begins to dilate again, this valve shuts tightly and obstructs the passage. The closing of these valves occasions the two heart-sounds, which we hear at the front of the chest. [Sidenote: 25. Heart-beats? The heart as a susceptible organ? Heat, exercise, etc.? Posture?] 25. FREQUENCY OF THE HEART'S ACTION.--The alternation of contraction and dilation constitutes the {113} heartbeats. These follow each other not only with great regularity, but with great rapidity. The average number in an adult man is about seventy-two in a minute. But the heart is a susceptible organ, and many circumstances affect its rate of action. Heat, exercise, and food will increase its action, as cold, fasting, and sleep will decrease it. Posture, too, has a curious influence; for if while sitting, the beats of the heart number seventy-one; standing erect will increase them to eighty-one, and lying down will lower them to sixty-six. [Sidenote: 26. Mental emotions? Sudden excitement? Excessive joy? The heart-beat rate? Bonaparte and Wellington?] 26. The modifying influence of mental emotions is very powerful. Sudden excitement of feeling will cause the heart to palpitate, or throb violently. Depressing emotions sometimes temporarily interrupt its movements, and the person faints in consequence. Excessive joy, grief, or fear, has occasionally suspended the heart's action entirely, and thus caused death. The rate of the heart-beat may be naturally above or below seventy-two. Thus it is stated that the pulse of the savage is always slower than that of the civilized man. Bonaparte and Wellington were very much alike in their heart's pulsations, which were less than fifty in the case of each. [Sidenote: 27. Average number of heart-beats? In one hour? Year? Lifetime?] 27. ACTIVITY OF THE HEART.--The average number of heart-beats during a lifetime may be considered as at the rate of seventy-two per minute, although this estimate is probably low; for during several years of early life the rate is above one hundred a minute. In one hour, then, the heart pulsates four thousand times; in a day, one hundred thousand times; and in a year, nearly thirty-eight million times. If we compute the number during a lifetime, thirty-nine years being the present average longevity of civilized mankind, we obtain as the vast aggregate, fourteen hundred millions of pulsations. {114} [Sidenote: 28. Amount of blood expelled? Theories of the ancients?] 28. Again, if we estimate the amount of blood expelled by each contraction of the ventricles, at four ounces, then the weight of the blood moved during one minute will amount to eighteen pounds. In a day it will be about twelve tons; in a year, four thousand tons; and in the course of a lifetime, over one hundred and fifty thousand tons. These large figures indicate, in some measure, the immense labor necessary to carry on the interior and vital operations of our bodies. In this connection, we call to mind the fanciful theories of the ancients in reference to the uses of the heart. They regarded it as the abode of the soul, and the source of the nobler emotions--bravery, generosity, mercy, and love. The words courage and cordiality are derived from a Latin word signifying heart. Many other words and phrases, as hearty, heart-felt, to learn by heart, and large-hearted, show how tenaciously these exploded opinions have fastened themselves upon our language. [Sidenote: 29. The tendency at the present time? Why is this view inadequate?] 29. At the present time the tendency is to ascribe purely mechanical functions to the heart. This view, like the older one, is inadequate; for it expresses only a small part of our knowledge of this organ. The heart is unlike a simple machine, because its motive power is not applied from without, but resides in its own substance. Moreover, it repairs its own waste, it lubricates its own action, and it modifies its movements according to the varying needs of the system. It is more than a mere force-pump, just as the stomach is something more than a crucible, and the eye something more than an optical instrument. [Sidenote: 30. What are the arteries? Their walls? Their membrane?] 30. THE ARTERIES.--The tube-like canals which carry the blood away from the heart are the arteries. Their walls are made of tough, fibrous materials, so that they sustain the mighty impulse of the heart, and are not ruptured. In common with the heart, the arteries have a {115} delicately smooth lining membrane. They are also elastic, and thus re-enforce the action of the heart: they always remain open when cut across, and after death are always found empty. [Sidenote: 31. Early anatomists? The service of the illustration?] 31. The early anatomists observed this phenomenon, and supposing that the same condition existed during life, came to the conclusion that these tubes were designed to act as air-vessels, hence the name artery, from a Greek word which signifies containing air. This circumstance affords us an illustration of the confused notions of the ancients in reference to the internal operations of the body. Cicero speaks of the arteries as "conveying the breath to all parts of the body." [Sidenote: 32. The arterial system? The branches and sub-branches of the arteries?] 32. The arterial system springs from the heart by a single trunk, like a minute and hollow tree, with numberless branches. As these branches leave the heart they divide and subdivide, continually growing smaller and smaller, until they can no longer be traced with the naked eye. If, then, we continue the examination by the aid of a microscope, we see these small branches sending off still smaller ones, until all the organs of the body are penetrated by arteries. [Sidenote: 33. Successive undulations from the heart? Course of the arteries? Protection of the arteries? General location of the arteries?] 33. THE PULSE.--With each contraction of the left heart, the impulse causes a wave-like motion to traverse the entire arterial system. If the arteries were exposed to view, we might see successive undulations speeding from the heart to the smallest of the branches, in about one-sixth part of a second. The general course of the arteries is as far as possible from the surface. This arrangement is certainly wise, as it renders them less liable to injury, the wounding of an artery being especially dangerous. It also protects the arteries from external and unequal pressure, by which the force of the heart would be {116} counteracted and wasted. Accordingly, we generally find these vessels hugging close to the bones, or hiding behind the muscles and within the cavities of the body. [Sidenote: 34. Where do the arteries lie? If we apply the finger? Pulse? Where felt?] 34. In a few situations, however, the arteries lie near the surface; and if we apply the finger to any of these parts, we will distinctly feel the movement described, taking place in harmony with the heart-beat. This is part of the wave-motion just mentioned, and is known as the pulse. All are more familiar with the pulse at the wrist, in the _radial_ artery; but the pulse is not peculiar to that position, for it may be felt in the _carotid_ of the neck, in the _temporal_ at the temple, and elsewhere, especially near the joints. [Illustration: FIG. 30.--THE FORM OF THE PULSE.] [Sidenote: 35. The pulse as an index? Of what does it inform the physician? Instrument for recording pulsation?] 35. Since the heart-beat makes the pulse, whatever affects the former affects the latter also. Accordingly, the pulse is a good index of the state of the health, so far as the health depends upon the action of the heart. It informs the physician of the condition of the circulation in four particulars: its rate, regularity, force, and fullness; and nearly every disease modifies in some respect the condition of the pulse. A very ingenious instrument, known as the sphygmograph, or pulse-writer, has recently been invented, by the aid of which the pulse is made to write upon paper its own signature, or rather to sketch its own profile. This instrument shows with great accuracy the difference between the pulses of health and those of disease. In Fig. 30 is traced the form of the pulse in health, which should be read from left to right. That part of the trace {117} which is nearly perpendicular coincides with the contraction of the ventricles; while the wavy portion marks their dilatation. [Sidenote: 36. What are the veins? How do they form? What do they resemble?] 36. THE VEINS.--The vessels which convey the blood on its return to the heart are the veins. They begin in the several organs of the body, and at first are extremely small; but uniting together as they advance, they constantly increase in size, reminding us of the way in which the fine rootlets of the plant join together to form the large roots, or of the rills and rivulets that flow together to form the large streams and rivers. In structure, the veins resemble the arteries, but their walls are comparatively inelastic. They are more numerous, and communicate with each other freely in their course, by means of interlacing branches. [Illustration: FIG. 31.--THE VALVES OF THE VEINS.] [Sidenote: 37. Valves in the veins? What are they? Their position? Experiment with the cord?] 37. But the chief point of distinction is in the presence of the valves in the veins. These are little folds of membrane, disposed in such a way, that they only open to receive blood flowing toward the heart, and close against a current in the opposite direction. Their position in the veins on the back of the hand may be readily observed, if we first obstruct the return of blood by a cord tied around the forearm or wrist. In a few minutes the veins will appear swollen, and upon them will be seen certain prominences, about an inch apart. These latter indicate the location of the valves, or, rather, they show that the vessels in front of the valves are distended by the blood, which cannot force a passage back through them. [Sidenote: 38. What will be proved by the experiment? What inference is drawn?] 38. This simple experiment proves that the true direction of the venous blood is toward the heart. That the color {118} of the blood is dark, will be evident, if we compare the hand thus bound by a cord with the hand not so bound. It also proves that the veins lie superficially, while the arteries are beneath the muscles, well protected from pressure; and that free communication exists from one vein to another. If now we test the temperature of the constricted member by means of a thermometer, we will find that it is colder than natural, although the amount of blood is larger than usual. From this fact we infer, that whatever impedes the venous circulation tends to diminish vitality; and hence, articles of clothing or constrained postures, that confine the body or limbs, and hinder the circulation of the blood, are to be avoided as injurious to the health. [Sidenote: 39. Capillaries? How regarded? Harvey?] 39. THE CAPILLARIES.--A third set of vessels completes the list of the organs of the circulation, namely, the _capillary_ vessels, so called (from the Latin word _capillaris_, hair-like), because of their extreme fineness. They are, however, smaller than any hair, having a diameter of about 1/3000 of an inch, and can only be observed by the use of the microscope. These vessels may be regarded as the connecting link between the last of the arteries and the first of the veins. The existence of these vessels was unknown to Harvey, and was the one step wanting to complete his great work. The capillaries were not discovered until 1661, a short time after the invention of the microscope. [Sidenote: 40. The circulation of the blood in the web of a frog's foot? Describe it. How general is the existence of the tissues?] 40. The circulation of the blood, as seen under the microscope, in the transparent web of a frog's foot, is a spectacle of rare beauty, possessing more than ordinary interest, when we consider that something very similar is taking place in our own bodies, on a most magnificent scale. It is like opening a secret page in the history of our own frames. We there see distinctly the three classes of vessels with their moving contents; first, the artery, {119} with its torrent of blood rushing down from the heart, secondly, the vein, with its slow, steady stream flowing in the opposite direction; and between them lies the network of capillaries, so fine that the corpuscles can only pass through "in single file." The current has here an uncertain or swaying motion, hurrying first in one direction, then hesitating, and then turning back in the opposite direction, and sometimes the capillaries contract so as to be entirely empty. Certain of the tissues are destitute of capillaries; such are cartilage, hair, and a few others on the exterior of the body. In all other structures, networks of these vessels are spread out in countless numbers: so abundant is the supply, that it is almost impossible to puncture any part with the point of a needle without lacerating tens, or even hundreds of these vessels. [Illustration: FIG. 32.--WEB OF A FROG'S FOOT, slightly magnified.] [Illustration: FIG. 33.--MARGIN OF FROG'S WEB magnified 30 diameters.] [Sidenote: 41. Elasticity of the capillaries? Grain of sand in the eye? Blush? Other cases?] 41. The capillaries are elastic, and may so expand as to produce an effect visible to the naked eye. If a grain of sand, or some other foreign particle, lodge in the eye, it will become irritated, and in a short time the white of the eye will be "blood-shot." This appearance is due to an {120} increase in the size of these vessels. A blush is another example of this, but the excitement comes through the nervous system, and the cause is some transient emotion, either of pleasure or pain. Another example is sometimes seen in purplish faces of men addicted to drinking brandy; in them the condition is a congestion of the capillary circulation, and is permanent, the vessels having lost their power of elastic contraction. [Sidenote: 42. Show what time is required for a given portion of blood to travel once around the body.] 42. RAPIDITY OF THE CIRCULATION.--That the blood moves with great rapidity is evident from the almost instant effects of certain poisons, as prussic acid, which act through the blood. Experiments upon the horse, dog, and other inferior animals, have been made to measure its velocity. If a substance, which is capable of a distinct chemical reaction (as _potassium ferrocyanide_, or _barium nitrate_), be introduced into a vein of a horse on one side, and blood be taken from a distant vein on the other side, its presence may be detected at the end of twenty or thirty-two seconds. In man, the blood moves with greater speed, and the circuit is completed in twenty-four seconds. [Sidenote: 43. Time required for all the blood to circulate completely around?] 43. What length of time is required for all the blood of the body to make a complete round of the circulation? This question cannot be answered with absolute accuracy, since the amount of the blood is subject to continual variations. But, if we assume this to be one-eighth of the weight of the body, about eighteen pounds, it will be sufficiently correct for our purpose. Now to complete the circuit, this blood must pass once through the left ventricle, the capacity of which is two ounces. Accordingly, we find that, under ordinary circumstances, all the blood makes one complete rotation every two minutes; passing successively through the heart, the capillaries of the lungs, the arteries, the capillaries of the extremities, and through the veins. {121} [Sidenote: 44. What is meant by assimilation? What can you say of its use, etc.? Time?] 44. ASSIMILATION.--The crowning act of the circulation, the furnishing of supplies to the different parts of the body, is effected by means of the capillaries. The organs have been wasted by use; the blood has been enriched by the products of digestion. Here, within the meshes of the capillary network, the needy tissues and the needed nutriment are brought together. By some mysterious chemistry, each tissue selects and withdraws from the blood the materials it requires, and converts them into a substance like itself. This conversion of lifeless food into living tissue is called assimilation. The process probably takes place at all times, but the period especially favorable for it is during sleep. Then the circulation is slower, and more regular, and most of the functions are at rest. The body is then like some trusty ship, which after a long voyage is "hauled up for repairs." [Sidenote: 45. What is stated of the injuries to the blood-vessels?] 45. INJURIES TO THE BLOOD-VESSELS.--It is important to be able to discriminate between an artery and a vein, in the case of a wound, and if we remember the physiology of the circulation we may readily do so. For, as we have already seen, hæmorrhage from an artery is much more dangerous than that from a vein. The latter tends to cease spontaneously after a short time. The arterial blood flows away from the heart with considerable force, in jets; its color being bright scarlet. The venous blood flows toward the heart from that side of the wound furthest from the heart; its stream being continuous and sluggish; its color dark. In an injury to an artery, pressure should be made between the heart and the wound; and in the case of a vein that persistently bleeds, it should be made upon the vessel beyond its point of injury. {122} QUESTIONS FOR TOPICAL REVIEW. PAGE 1. In what organisms is the so-called circulatory fluid found? 101 2. How is it designated in the different organisms? 101 3. What can you state of the importance of blood to the body? 101, 105 4. Of its great abundance, color, and composition? 101, 102, 107 5. Describe the corpuscles of the human blood. 102, 103, 104 6. What is said of them in comparison with those of the lower animals? 103 7. Of the importance of sometimes detecting human from other blood? 103 8. What means have we of detecting blood in spots or stains? 103, 104 9. What is meant by coagulation of the blood? 104 10. What wisdom is there in the law of the blood's coagulation? 104, 105 11. How is this wisdom made manifest? 105 12. In what cases is the aid of the surgeon required? 105 13. What are the two great uses of the blood? 105 14. Through what mediums is the blood provided with new material and relieved of the old material? 105 15. What do you understand by the operation called transfusion? 106 16. What cases of transfusion are reported of the lower animals? 106 17. What can you state of transfusion as practised upon man? 106 18. What further can you say on the subject? 106, 107 19. What changes take place in the color of the blood in its journey through the system? 107 20. State all you can in relation to the circulation of the blood. 107 21. All, in relation to the size, shape, and location of the heart. 107, 109 22. How is the loss of power in the heart movements obviated? 109 23. Give a description of the formation of the heart. 109, 110, 111 24. What can you state of the ventricles and auricles of the heart? 110 25. Describe the action of the heart. 111 26. What special vitality does the tissue of the heart possess? 111 27. State all you can on the subject. 111 28. Describe the course of the blood through the cavities of the heart. 112 29. Describe the mechanism that regulates the heart-currents. 112 30. How do you account for the two heart-sounds at the front of the chest? 112 31. State what you can of the frequency of the heart's action. 112, 113 32. Of the activity of the heart. 113, 114 33. What do you understand by the arteries? 114, 115 34. State what you can of the arteries and the arterial system. 114, 115 35. What do you understand by the pulse? 115, 116 36. In what part of the body may the pulse be felt? 116 37. What further can you state of the pulse? 116, 117 38. What are the veins? 117 39. Where do they exist, and how are they formed? 117 40. Describe the valves of the veins and their uses. 117 41. Now give a full description of the construction of the veins. 117 42. What further can you state of the veins? 117, 118 43. What do you understand by the capillaries? 118, 119 44. What service do the capillaries perform? 118, 119, 121 45. Describe the circulation of the blood in the region of the heart. 118, 119 46. What can you state of the rapidity of the blood's circulation? 120 47. Of the process known as assimilation? 121 48. Of injuries to the blood-vessels? 121 * * * * * {123} CHAPTER VIII. RESPIRATION. _The Objects of Respiration--The Lungs--The Air-Passages--The Movements of Respiration--Expiration and Inspiration--The Frequency of Respiration--Capacity of the Lungs--The Air we breathe--Changes in the Air from Respiration--Changes in the Blood--Interchange of Gases in the Lungs--Comparison between Arterial and Venous Blood--Respiratory Labor--Impurities of the Air--Dust--Carbonic Acid--Effects of Impure Air--Nature's Provision for Purifying the Air--Ventilation--Animal Heat--Spontaneous Combustion._ [Sidenote: 1. Difference between the two sets of capillaries? Change effected by respiration or breathing?] 1. THE OBJECT OF RESPIRATION.--In one set of capillaries, or hair-like vessels, the blood is impoverished for the support of the different members and organs of the body. In another capillary system the blood is refreshed and again made fit to sustain life. The former belongs to the greater or _systemic_ circulation; the latter to the lesser or _pulmonary_, so called from _pulmo_, the lungs, in which organs it is situated. The blood, as sent from the right side of the heart to the lungs, is venous, dark, impure, and of a nature unfit to circulate again through the tissues. But, when the blood returns from the lungs to the left side of the heart, it has become arterial, bright, pure, and no longer hurtful to the tissues. This marvellous purifying change is effected by means of the very familiar act of respiration, or breathing. [Sidenote: 2. What are the lungs? How many lungs are there? Lung-substance? Its properties? The pleura?] 2. THE LUNGS.--The lungs are the special organs of respiration. There are two of them, one on each side of the chest, which cavity they, with the heart, almost wholly occupy. The lung-substance is soft, elastic, and sponge-like. Under pressure of the finger, it _crepitates_, or crackles, and floats when thrown into water; these properties being {124} due to the presence of air in the minute air-cells of the lungs. To facilitate the movements necessary to these organs, each of them is provided with a double covering of an exceedingly smooth and delicate membrane, called the _pleura_. One layer of the pleura is attached to the walls of the chest, and the other to the lungs; and they glide, one upon the other, with utmost freedom. Like the membrane which envelops the heart, the pleura secretes its own lubricating fluid, in quantities sufficient to keep it always moist. [Illustration: FIG. 34.--ORGANS OF THE CHEST. A, Lungs. B, Heart. D, Pulmonary Artery. E, Trachea.] {125} [Illustration: FIG. 35.--LARYNX, TRACHEA, AND BRONCHIAL TUBES.] [Illustration: FIG. 36.--DIAGRAM AND SECTION OF THE AIR-CELLS.] [Sidenote: 3. Communication of the lungs with the external air? Bronchial tubes?] 3. THE AIR-PASSAGES. --The lungs communicate with the external air by means of certain air-tubes, the longest of which, the _trachea_, or windpipe, runs along the front of the neck (Fig. 34, E, and 35). Within the chest this tube divides into two branches, one entering each lung; these in turn give rise to numerous branches, or bronchial tubes, as they are called, which gradually diminish in size until they are about one-twenty-fifth of an inch in diameter. Each of these terminates in a cluster of little pouches, or "air-cells," having very thin walls, and covered with a capillary network, the most intricate in the body (Fig. 36). [Sidenote: 4. Office of the bronchial tubes? What further can you state of them?] 4. These tubes are somewhat flexible, sufficiently so to bend when the parts move in which they are situated; but they are greatly strengthened by bands or rings of cartilage which keep the passages always open; otherwise there would be a constantly-recurring tendency to collapse after every breath. The lung-substance essentially consists of these bronchial tubes and terminal air-cells, with the blood-vessels ramifying about them (Fig. 37). At the top of the trachea is the larynx, a sort of {126} box of cartilage, across which are stretched the vocal cords. Here the voice is produced chiefly by the passage of the respired air over these cords, causing them to vibrate. [Illustration: FIG. 37.--SECTION OF THE LUNGS.] [Sidenote: 5. The epiglottis? When it does not close in time, what is the consequence?] 5. Over the opening of the larynx is found the _epiglottis_, which fits like the lid of a box at the entrance to the lungs, and closes during the act of swallowing, so that food and drink shall pass backward to the oesophagus, or gullet (Fig. 38). Occasionally it does not close in time, and some substance intrudes within the larynx, when we at once discover, by a choking sensation, that "something has gone the wrong way," and, by coughing, we attempt to expel the unwelcome intruder. The epiglottis is one of the many safeguards furnished by nature for our security and {127} comfort, and is planned and put in place long before these organs are brought into actual use in breathing and in taking food. [Illustration: FIG. 38.--SECTION OF MOUTH AND THROAT. A, The Tongue. B, The Uvula C, Vocal Cord. E, Epiglottis. L, Larynx. N, Trachea. O, Oesophagus.] [Sidenote: 6. Lining of the air-passages? Ciliated cells? Their uses? The three diseases of the lungs?] {128} [Illustration: FIG. 39.--CILIATED CELLS.] 6. The air-passages are lined through nearly their whole extent with mucous membrane, which maintains these parts in a constantly moist condition. This membrane has a peculiar kind of cells upon its outer surface. If examined under a powerful microscope, we may see, even for a considerable time after their removal from the body, that these cells have minute hair-like processes in motion, which wave like a field of grain under the influence of a breeze (Fig. 39). This is a truly beautiful sight; and since it is found that these little _cilia_, as they are called, always produce currents in one direction, from within outward, it is probable that they serve a useful purpose in catching and carrying away from the lungs dust and other small particles drawn in with the breath (Fig. 39). The three diseases which more commonly affect the lungs, as the result of exposure, are pneumonia, or inflammation of the lungs, implicating principally the air-cells; bronchitis, an inflammation of the large bronchial tubes; and pleurisy, an inflammation of the investing membrane of the lungs, or pleura. Among the young, an affection of the trachea takes place, known as croup. [Sidenote: 7. The act of breathing? Extension of the chest by breathing?] 7. THE MOVEMENTS OF RESPIRATION.--The act of breathing has two parts--(1), _inspiration_, or drawing air into the lungs, and (2), _expiration_, or expelling it from the lungs again. In inspiration, the chest extends in its length, breadth, and height, or width. We can prove that this is the case as regards the two latter, by observing the effect of a deep breath. The ribs are elevated by means of numerous muscles, some of which occupy the entire spaces between those bones. But the increase in length, or vertically, is not so apparent, as it is caused by a muscle within the body called the _diaphragm_, it being the thin partition which separates the chest from the abdomen, rising like a dome within the chest. (Fig. 16). {129} [Sidenote: 8. Contraction of the diaphragm? Power of the diaphragm? Effects of extending the walls of the chest? The habit of taking frequent and deep inspirations?] 8. With every inspiration, the diaphragm contracts, and in so doing, approaches more nearly a plane, or horizontal, surface, and thus enlarges the capacity of the chest. Laughing, sobbing, hiccoughing, and sneezing are caused by the spasmodic or sudden contraction of the diaphragm. The special power of this muscle is important in securing endurance, or "long wind," as it is commonly expressed; which may be obtained mainly by practice. It is possessed in a marked degree by the mountaineer, the oarsman, and the trained singer. As the walls of the chest extend, the lungs expand, and the air rushes in to fill them. This constitutes an inspiration. The habit of taking frequent and deep inspirations, in the erect position, with the shoulders thrown back, tends greatly to increase the capacity and power of the organs of respiration. [Sidenote: 9. Expiration? The mechanism of expiration?] 9. EXPIRATION is a less powerful act than inspiration. The diaphragm relaxes its contraction, and ascends in the form of a dome; the ribs descend and contract the chest; while the lungs themselves, being elastic, assist to drive out the air. The latter passes out through the same channels by which it entered. At the end of each expiration there is a pause, or period of repose, lasting about as long as the period of action. [Sidenote: 10. Frequency of respiration? Effect of hurried action of the heart?] 10. FREQUENCY OF RESPIRATION.--It is usually estimated that we breathe once during every four beats of the heart, or about eighteen times in a minute. There is, of course, a close relation between the heart and lungs, and whatever modifies the pulse, in like manner affects the breathing. When the action of the heart is hurried, a larger amount of blood is sent to the lungs, and, as the consequence, they must act more rapidly. Occasionally, the heart beats so very forcibly that the lungs cannot keep pace with it, and then we experience a peculiar sense of {130} distress from the want of air. This takes place when we run until we are "out of breath." At the end of every fifth or sixth breath, the inspiration is generally longer than usual, the effect being to change more completely the air of the lungs. [Sidenote: 11. Respiration controlled by the will? Advantage of the knowledge to us?] 11. Although, as a general rule, the work of respiration goes on unconsciously and without exertion on our part, it is nevertheless under the control of the will. We can increase or diminish the frequency of its acts at pleasure, and we can "hold the breath," or arrest it altogether for a short time. From twenty to thirty seconds is ordinarily the longest period in which the breath can be held; but if we first expel all the impure air from the lungs, by taking several very deep inspirations, the time may be extended to one and a half or even two minutes. This should be remembered, and acted upon, before passing through a burning building, or any place where the air is very foul. The arrest of the respiration may be still further prolonged by training and habit; thus it is said, the pearl-fishers of India can remain three or four minutes under water without being compelled to breathe. [Sidenote: 12. Capacity of the lungs? Time required to renovate the air in the lungs? In tranquil respiration? Importance of the provision?] 12. CAPACITY OF THE LUNGS.--The lungs are not filled and emptied by each respiration. For while their full capacity, in the adult, is three hundred and twenty cubic inches, or more than a gallon, the ordinary breathing air is only one-sixteenth part of that volume, or twenty cubic inches, being two-thirds of a pint. Accordingly, a complete renovation, or rotation, of the air of the lungs does not take place more frequently than about once in a minute; and by the gradual introduction of the external air, its temperature is considerably elevated before it reaches the delicate pulmonary capillaries. In tranquil respiration, less than two-thirds of the breathing power is {131} called into exercise, leaving a reserve capacity of about one hundred and twenty cubic inches, equivalent to three and one half pints. This provision is indispensable to the continuation of life; otherwise, a slight embarrassment of respiration, by an ordinary cold, for instance, would suffice to cut off the necessary air, and the spark of life would be speedily extinguished. [Sidenote: 13. The atmosphere? How high or deep? How essential to life? Marine life in perfectly pure water and air?] 13. THE AIR WE BREATHE.--The earth is enveloped on all sides by an invisible fluid, called the atmosphere. It forms a vast and shoreless ocean of air, forty-five miles deep, encircling and pervading all objects on the earth's surface, which is absolutely essential for the preservation of all vegetable and animal life,--in the sea, as well as on the land and in the air. At the bottom, or in the lower strata of this aerial ocean, we move and have our being. Perfectly pure water will not support marine life, for a fish may be drowned in water from which the air has been exhausted, just as certainly as a mouse, or any other land animal, will perish if put deeply into the water for a length of time. The cause is the same in both cases: the animal is deprived of the requisite amount of air. It is also stated, that if the water-supply of the plant be deprived of air, its vital processes are at once checked. [Sidenote: 14. Composition of the air? Properties of the two gases?] 14. The air is not a simple element, as the ancients supposed, but is formed by the mingling of two gases, known to the chemist as oxygen and nitrogen, in the proportion of one part of the former to four parts of the latter. These gases are very unlike, being almost opposite in their properties: nitrogen is weak, inert, and cannot support life; while oxygen is powerful, and incessantly active; and is the essential element which gives to the atmosphere its power to support life and combustion. The discovery of this fact was made by the French chemist, Lavoisier, in 1778. {132} [Sidenote: 15. Air once breathed? An animal in it? A candle? Analysis of expired air? Change in volume?] 15. CHANGES IN THE AIR FROM RESPIRATION.--Air that has been once breathed is no longer fit for respiration. An animal confined within it will sooner or later die; so too, a lighted candle placed in it will be at once extinguished. If we collect a quantity of expired air and analyze it, we shall find that its composition is not the same as that of the inspired air. When the air entered the lungs it was rich in oxygen; now it contains twenty-five per cent. less of that gas. Its volume, however, remains nearly the same; its loss being replaced by another and very different gas, which the lungs exhaled, called _carbonic acid_, or, as the chemist terms it, _carbon dioxide_. [Sidenote: 16. What else has the expired air gained? When and where noticed?] 16. The expired air has also gained moisture. This is noticed when we breathe upon a mirror, or the window-pane, the surface being tarnished by the condensation of the watery vapor exhaled by the lungs. In cold weather, this causes the fine cloud which is seen issuing from the nostrils or mouth with each expiration, and contributes in forming the feathery crystals of ice which decorate our window-panes on a winter's morning. [Sidenote: 17. Nature of the watery vapor? Its effects upon animals?] 17. This watery vapor contains a variable quantity of animal matter, the exact nature of which is unknown; but when collected it speedily putrefies and becomes highly offensive. From the effects, upon small animals, of confinement in their own exhalations, having at the same time an abundant supply of fresh air, it is believed that the organic matters thrown off by the lungs and skin are direct and active poisons; and that to such emanations from the body, more than to any other cause, are due the depressing and even fatal results which follow the crowding of large numbers of persons into places of limited capacity. {133} [Sidenote: 18. Give some of the instances furnished by history.] 18. History furnishes many painful instances of the ill effects of overcrowding. In 1756, of one hundred and forty-six Englishmen imprisoned in the Black Hole of Calcutta, only twenty-three, at the end of eight hours, survived. After the battle of Austerlitz, three hundred prisoners were crowded into a cavern, where, in a few hours, two-thirds of their number died. On board a steam-ship, during a stormy night, one hundred and fifty passengers were confined in a small cabin, but when morning came, only eighty remained alive. [Sidenote: 19. Change in the blood from blue to red. Upon what does the change depend? How shown?] 19. CHANGES IN THE BLOOD FROM RESPIRATION.--The most striking change which the blood undergoes by its passage through the lungs, is the change of color from a dark blue to bright red. That this change is dependent upon respiration has been fully proved by experiment. If the trachea, or windpipe, of a living animal be so compressed as to exclude the air from the lungs, the blood in the arteries will gradually grow darker, until its color is the same as that of the venous blood. When the pressure is removed the blood speedily resumes its bright hue. Again, if the animal be made to breathe an atmosphere containing more oxygen than atmospheric air, the color changes from scarlet to vermilion, and becomes even brighter than arterial blood. This change of color is not of itself a very important matter, but it indicates a most important change of composition. [Sidenote: 20. What does the air lose and gain by respiration? What, the blood? Air as food?] 20. The air, as we have seen, by respiration loses oxygen and gains carbonic acid: the blood, on the contrary, gains oxygen and loses carbonic acid. The oxygen is the food of the blood corpuscles; while the articles we eat and drink belong more particularly to the plasma of the blood. The air, then, it is plain, is a sort of food, and we should {134} undoubtedly so regard it, if it were not for the fact that we require it constantly, instead of taking it at stated intervals, as is the case with our articles of diet. Again, as the demand of the system for food is expressed by the sensation of hunger, so the demand for air is marked by a painful sensation called suffocation. [Sidenote: 21. Moist animal membranes? How shown with the bladder?] 21. INTERCHANGE OF GASES IN THE LUNGS.--As the air and the blood are not in contact, they being separated from each other by the walls of the air-cells and of the blood-vessels, how can the two gases, oxygen and carbonic acid, exchange places? Moist animal membranes have a property which enables them to transmit gases through their substance, although they are impervious to liquids. This may be beautifully shown by suspending a bladder containing dark blood in a jar of oxygen. At the end of a few hours the oxygen will have disappeared, the blood will be brighter in color, and carbonic acid will be found in the jar. [Sidenote: 22. Gaseous diffusion? If oxygen be not received? If carbonic acid be retained?] 22. If this interchange takes place outside of the body, how much more perfectly must it take place within, where it is favored by many additional circumstances! The walls of the vessels and the air-cells offer no obstacle to this process, which is known as gaseous diffusion. Both parts of the process are alike of vital importance. If oxygen be not received, the organs cease to act; and if carbonic acid be retained in the blood, its action is that of a poison; unconsciousness, convulsions, and death following. [Sidenote: 23. Difference in the appearance and composition of the blood? Temperature of the blood? The blood while passing through the lungs? The consequence?] 23. DIFFERENCE BETWEEN ARTERIAL AND VENOUS BLOOD.--The following table presents the essential points of difference in the appearance and composition of the blood, before and after its passage through the lungs:-- {135} _Venous Blood._ _Arterial Blood._ Color, Dark blue, Scarlet. Oxygen, 8 per cent., 18 per cent. Carbonic Acid, 15 to 20 per cent., 6 per cent., or less. Water, More, Less. The temperature of the blood varies considerably; but the arterial stream is generally warmer than the venous. The blood imparts heat to the air while passing through the lungs, and consequently the contents of the right side of the heart has a higher temperature than the contents on the left side. [Sidenote: 24. What do we learn by means of the spectroscope? "Carriers of oxygen?" Blue blood in the system?] 24. By means of the spectroscope, we learn that the change of color in the blood has its seat in the corpuscles; and that, according as they retain oxygen, or release it, they present the spectrum of arterial or venous blood. There evidently exists, on the part of these little bodies, an affinity for this gas, and hence they have been called "carriers of oxygen." It was long ago thought that blue blood was a trait peculiar to persons of princely and royal descent, and boastful allusions to the "_sang azure_" of kings and nobles are quite often met with. Physiology, however, informs us that blue blood flows in the veins of the low as well as the high, and that so far from its presence indicating a mark of purity, it, in reality, represents the waste and decay of the system. [Sidenote: 25. The amount of air that passes in and out of the lungs?] 25. AMOUNT OF RESPIRATORY LABOR.--During ordinary calm respiration, we breathe eighteen times in a minute; and twenty cubic inches of air pass in and out of the lungs with every breath. This is equivalent to the use of three hundred and sixty cubic inches, or more than ten pints of air each minute. From this we calculate that the quantity of air which hourly traverses the lungs is about thirteen cubic feet, or seventy-eight gallons; and daily, not {136} less than three hundred cubic feet, an amount nearly equal to the contents of sixty barrels. [Sidenote: 26. Air absorbed in its transit through the lungs? The loss? Carbonic acid exhaled? Effect of excitement or exertion? What estimate?] 26. Of this large volume of air five per cent. is absorbed in its transit through the lungs. The loss thus sustained is almost wholly of oxygen, and amounts to fifteen cubic feet daily. The quantity of carbonic acid exhaled by the lungs during the day is somewhat less, being twelve cubic feet. Under the influence of excitement or exertion, the breathing becomes more frequent and more profound; and then the internal respiratory work increases proportionately, and may even be double that of the above estimate. It has been estimated that in drawing a full breath, a man exerts a muscular force equal to raising two hundred pounds placed upon the chest. [Sidenote: 27. Importance of the oxygen in the atmosphere? Injurious character of gases?] 27. IMPURITIES OF THE AIR.--The oxygen in the atmosphere is of such prime importance, and its proportion is so nicely adjusted to the wants of man, that any gas or volatile substance which supplants it must be regarded as a hurtful impurity. All gases, however, are not alike injurious. Some, if inhaled, are necessarily fatal; _arsenuretted hydrogen_ being one of these, a single bubble of which destroyed the life of its discoverer, Gehlen. Others are not directly dangerous, but by taking the place of oxygen, and excluding it from the lungs, they become so. Into this latter class we place carbonic acid. [Sidenote: 28. Pungency of gases? The inference? Our safeguard?] 28. Most of the actively poisonous gases have a pungent or offensive odor; and, as may be inferred, most repugnant odors indicate the presence of substances unfit for respiration. Accordingly, as we cannot see or taste these impurities, the sense of smell is our principal safeguard against them; and we recognize the design which has planted this sense, like a sentinel at the proper entrance of the {137} air-passages, the nostrils, to give us warning of approaching harm. Take, as an example, the ordinary illuminating gas of cities, from which so many accidents happen. How many more deaths would it cause if, when a leak occurs, we were not able to discover the escape of the gas by means of its disagreeable odor. [Sidenote: 29. The air of rooms in which fever-sick persons are confined?] 29. Organic matters exist in increased measure in the expired breath of sick persons, and impart to it, at times, a putrid odor. This is especially true in diseases which, like typhus and scarlet fever, are referable to a blood poison. In such cases the breath is one of the means by which nature seeks to expel the offending material from the system. Hence, those who visit or administer to fever-sick persons should obey the oft-repeated direction, "not to take the breath of the sick." At such times, if ever, fresh air is demanded, not alone for the sick, but as well for those who are in attendance. [Sidenote: 30. Animalcula in the water? Dust in the air?] 30. DUST IN THE AIR.--Attention has lately been directed to the dust, or haze, that marks the ray of sunshine across a shaded room. Just as, many years ago, it was discovered that myriads of animalcula infested much of the water we drank, so now the microscope reveals "the gay motes that dance along a sunbeam" to be, in part, composed of multitudes of animal and vegetable forms of a very low grade, the germs of fermentation and putrefaction, and the probable sources of disease. [Sidenote: 31. The best air filter? The remarks of Prof. Tyndall?] 31. It is found that the best filter by which to separate this floating dust from the air is cotton wool, although a handkerchief will imperfectly answer the same purpose. In a lecture on this subject by Prof. Tyndall, he remarks that, "by breathing through a cotton wool respirator, the noxious air of the sick room is restored to practical purity. Thus filtered, attendants may breathe the air unharmed. {138} In all probability, the protection of the lungs will be the protection of the whole system. For it is exceedingly probable that the germs which lodge in the air-passages are those which sow epidemic disease in the body. If this be so, then disease can certainly be warded off by filters of cotton wool. By this means, so far as the germs are concerned, the air of the highest Alps may be brought into the chamber of the invalid." [Sidenote: 32. Carbonic acid in volcanic regions? In Java? At Lake Avernus? In mines?] 32. CARBONIC ACID IN THE AIR.--We have already spoken of this gas as an exhalation from the lungs, and a source of impurity; but it exists naturally in the atmosphere in the proportion of one half part per thousand. In volcanic regions it is poured forth in enormous quantities from fissures in the earth's surface. Being heavier than air, it sometimes settles into caves and depressions in the surface. It is stated that in the island of Java, there is a place called the "Valley of Poison," where the ground is covered with the bones of birds, tigers, and other wild animals, which were suffocated by carbonic acid while passing. The Lake Avernus, the fabled entrance to the infernal regions, was, as its name implies, bird-less, because the birds, while flying over it, were poisoned by the gas and fell dead into its waters. In mines, carbonic acid forms the dreaded _choke-damp_, while carburetted hydrogen is the _fire-damp_. [Sidenote: 33. In the open air? Amount of carbonic acid exhaled by a man? A gas-burner? A room fire? From furnaces?] 33. In the open air, men seldom suffer from carbonic acid, for, as we shall see presently, nature provides for its rapid distribution, and even turns it to profitable use. But its ill effects are painfully evident in the abodes of men, in which it is liable to collect as the waste product of respiration and of that combustion which is necessary for lighting and warming our homes. A man exhales, during repose, not less than one-half cubic foot of carbonic acid per hour. One gas-burner liberates five cubic feet in the {139} same time, and spoils about as much air as ten men. A fire burning in a grate or stove emits some gaseous impurity, and at the same time abstracts from the air as much oxygen as twelve men would consume in the same period, thus increasing the relative amount of carbonic acid in the air. From furnaces, as ordinarily constructed, this gas, with other products of combustion, is constantly leaking and vitiating the air of tightly-closed apartments. [Sidenote: 34. Effects of inhaling carbonic acid alone? In small quantities?] 34. EFFECTS OF IMPURE AIR.--Carbonic acid, in its pure form, is irrespirable, causing rapid death by suffocation. Air containing forty parts per thousand of this gas (the composition of the expired breath) extinguishes a lighted candle, and is fatal to birds; when containing one hundred parts, it no longer yields oxygen to man and other warm-blooded animals; and is of course at once fatal to them. In smaller quantities, this gas causes headache, labored respiration, palpitation, unconsciousness, and convulsions. [Sidenote: 35. Effects of the air in crowded and badly ventilated rooms?] 35. In crowded and badly ventilated apartments, where the atmosphere relatively contains from six to ten times the natural amount of carbonic acid, the contaminated air causes dulness, drowsiness, and faintness; the dark, impure blood circulating through the brain, oppressing that organ and causing it to act like a blunted tool. This is a condition not uncommon in our schools, churches, court-rooms, and the like, the places of all others where it is desirable that the mind should be alert and free to act; but, unhappily, an unseen physiological cause is at work, dispensing weariness and stupor over juries, audience, and pupils. [Sidenote: 36. A cause of consumption? How was the fact illustrated?] 36. Another unmistakable result of living in and breathing foul air is found in certain diseases of the lungs, especially consumption. For many years the barracks of {140} the British army were constructed without any regard to ventilation; and during those years the statistics showed that consumption was the cause of a very large proportion of deaths. At last the government began to improve the condition of the buildings, giving larger space and air-supply; and as a consequence, the mortality from consumption has diminished more than one-third. [Sidenote: 37. How, in the case of the lower animals? Tendency of certain occupations?] 37. The lower animals confined in the impure atmosphere of menageries, contract the same diseases as man. Those brought from a tropical climate, and requiring artificial warmth, generally die of consumption. In the Zoological gardens of Paris, this disease affected nearly all monkeys, until care was taken to introduce fresh air by ventilation; and then it almost wholly disappeared. The tendency of certain occupations to shorten life is well known; disease being occasioned by the fumes and dust which arise from the material employed, in addition to the unhealthful condition of the workshop or factory where many hours are passed daily. [Sidenote: 38. Give the fact as set forth in the table.] 38. The following table shows the comparative amount of carbonic acid in the air under different conditions and the effects sometimes produced:-- PROPORTION OF CARBONIC ACID. In 1000 parts of Air. Air of country. .4 " " city. .5 In hospital, well ventilated. .6 In school, church, etc., fairly ventilated. 1.2 to 2.5 In court-house, factory, etc., without ventilation. 4. to 40. In bedroom, before being aired. 4.5 In bedroom, after being aired. 1.5 Constantly breathed, causing ill health. 2. Occasionally breathed, causing discomfort. 3. Occasionally breathed, causing distress. 10. Expired air. 40. Air no longer yielding oxygen 100. {141} [Sidenote: 39. What can you state of the diffusive power of gases? The added influence of the winds?] 39. NATURE'S PROVISION FOR PURIFYING THE AIR.--We have seen that carbonic acid is heavier than air, and is poisonous. Why, then, does it not sink upon and overwhelm mankind with a silent, invisible wave of death? Among the gases there is a more potent force than gravity, which forever precludes such a tragedy. It is known as the diffusive power of gases. It acts according to a definite law, and with a resistless energy compelling these gases, when in contact, to mingle until they are thoroughly diffused. The added influence of the winds is useful, by insuring more rapid changes in the air; air in motion being perfectly wholesome. The rains also wash the air. [Sidenote: 40. How is the constant purity of the air secured? Explain the process?] 40. We have seen that the whole animal creation is constantly abstracting oxygen from the atmosphere, and as constantly adding to it vast volumes of a gas injurious alike to all, even in small quantities. How, then, does the air retain, unchanged, its life-giving properties? The constant purity of the air is secured by means of the vegetable creation. Carbonic acid is the food of the plants, and oxygen is its waste product. The leaves are its lungs, and under the stimulus of sunlight a vegetable respiration is set in motion, the effects of which are just the reverse of the function we have been considering. Thus nature purifies the air, and at the same time builds up beautiful and useful forms of life from elements of decay. [Sidenote: 41. What process occurs in the sea? How is the fact illustrated?] 41. In the sea, as in the air, the same circle of changes is observed. Marine animals consume oxygen and give off carbonic acid; while marine plants consume carbonic acid and liberate oxygen. Taking advantage of this fact, we may so arrange aquaria with fishes and sea-plants, in their proper combinations, so that each supplies the needs of the other, and the water requires seldom to be renewed. This {142} affords us, on a small scale, an illustration of the mutual dependence of the two great kingdoms of nature; as well as of those compensating changes which are taking place on such a grand scale in the world about us. [Sidenote: 42. Character of the external air? Of the air in our dwellings? What becomes imperative? Imperfect ventilation of our dwellings?] 42. VENTILATION.--Since the external atmosphere, as provided by nature, is always pure, and since the air in our dwellings and other buildings is almost always impure, it becomes imperative that there should be a free communication from the one to the other. This we aim to accomplish by ventilation. As our houses are ordinarily constructed, the theory of ventilation, "to make the internal as pure as the external air," is seldom carried out. Doors, windows, and flues, the natural means of replenishing the air, are too often closed, almost hermetically, against the precious element. Special means, or special attention, must therefore be used to secure even a fair supply of fresh air. This is still more true of those places of public resort, where many persons are crowded together. [Sidenote: 43. What hints are given for the ventilation of our dwellings?] 43. If there are two openings in a room, one as a vent for foul air, and the other an inlet for atmospheric air, and if the openings be large, in proportion to the number of air consumers, the principal object will be attained. Thus, a door and window, each opening into the outer air, will ordinarily ventilate a small apartment; or a window alone will answer, if it be open both above and below, and the open space at each end be not less than one inch for each occupant of the room, when the window is about a yard wide. The direction of the current is generally from below upward, since the foul, heated air tends to rise; but this is not essential. Its rate need not be rapid; a "draught," or perceptible current, is never necessary to good ventilation. The temperature of the air admitted may be warm or cold. It is thought by many that if the {143} air is cold, it is pure; but this is an error, since cold air will receive and retain the same impurities as warm air. [Sidenote: 44. State what Florence Nightingale says about inhaling night air?] 44. Shall we open our bedrooms to the night air? Florence Nightingale says, in effect, that night air is the only air that we can then breathe. "The choice is between pure air without and impure air within. Most people prefer the latter,--an unaccountable choice. An open window, most nights in the year, can hurt no one. In great cities, night air is the best and purest to be had in twenty-four hours. I could better understand, in towns, shutting the windows during the day than during the night." [Sidenote: 45. Warmth of the bird as compared with that of the air? Of the fish and the water? Heat in animals and plants? How illustrated with the thermometer?] 45. ANIMAL HEAT.--Intimately connected with respiration is the production of animal heat, or the power of maintaining the temperature of the body above that of the medium in which the creature moves; thus, the bird is warmer than the air, and the fish than the water. This elevation of temperature is a result of the various chemical changes which are constantly taking place in the system. Although common to all animals, in a greater or less degree, heat is not peculiar to them; since plants also generate it, especially at the time of sprouting and flowering. If a thermometer be placed in a cluster of geranium flowers, it will indicate a temperature several degrees above that of the surrounding air. [Sidenote: 46. Amount of heat in animals, how apportioned? As regards the birds? Frogs, and other sluggish animals? Arrangement made by zoologists?] 46. Among animals great differences are noticed in this respect, but the degree of heat produced is always proportional to the activity of respiration and the amount of oxygen consumed. Accordingly, the birds, whose habits are extremely active, and whose breathing capacity is the greatest, have uniformly the highest temperature. Sluggish animals, on the contrary, as frogs, lizards, and snakes, have little need for oxygen, and have incompletely {144} developed lungs; these animals are cold to the touch, that is, they have relatively a lower temperature than man, and their positive temperature is but little above that of the external air. Accordingly, zoologists have so arranged the animal kingdom that _warm-blooded_ animals, including man, the birds, and the quadrupeds, are classified together; while the _cold-blooded_ animals, such as the fish, tortoise, frog, and all that have no vertebral column, are classed by themselves. [Sidenote: 47. State what is said respecting the temperature of the human body.] 47. The temperature of the human body is about 100° Fahrenheit, and remains about the same through winter and summer, in the tropics as well as in the frozen regions of the north. It may change temporarily within the range of about twelve degrees; but any considerable, or long-continued elevation or diminution of the bodily heat is certain to result disastrously. [Sidenote: 48. Ability of man to adapt himself to different climates? In what does the power to resist cold consist? What is said about warm clothing?] 48. Man is able to adapt himself to all extremes of climate; and, in fact, by means of clothing, shelter, and food, is able to create for himself an artificial climate where-ever he choses to reside. The power to resist cold consists chiefly in preventing the heat which is generated by the vital processes of the body from being lost by radiation. Warm clothing, such as we wear in winter, has, in reality, the same temperature as that which is worn in summer; but, by reason of being thick and porous, it is a bad conductor of heat, and thus prevents the escape of that produced by the body. If woollen fabrics were intrinsically warm, no one would wrap a piece of flannel, or blanket, around a block of ice to prevent its melting in summer. [Sidenote: 49. Men in an atmosphere above the boiling-point? In foundries and glass works?] 49. The faculty of generating heat explains how it is that we are enabled to resist the effects of cold; but how does the body withstand a temperature higher than its {145} own? Men have been known to remain several minutes in an atmosphere heated above the boiling-point of water, and yet the temperature of their own bodies was not greatly elevated. Those who labor in foundries and glass-works are habitually subjected to very high degrees of temperature, but they do not suffer in health more than those engaged in many other occupations. [Sidenote: 50. The regulation of the temperature of the body. Give the explanation.] 50. The regulation of the temperature of the body is effected by means of perspiration, and by its evaporation. So long as the skin acts freely and the air freely absorbs the moisture, the heat of the body does not increase, for whenever evaporation takes place, it is attended by the abstraction of heat--that is, the part becomes relatively colder. This may be tested by moistening some part of the surface with cologne, ether, or other volatile liquid, and then causing it to evaporate rapidly by fanning. The principle that evaporation produces cold has been ingeniously and practically employed, in the manufacture of ice, by means of freezing machines. [Sidenote: 51, 52. State what is said of spontaneous combustion.] 51. SPONTANEOUS COMBUSTION.--Is it possible that the temperature of the living body can be so increased, that its tissues will burn spontaneously? From time to time, cases have been reported in which, by some mysterious means, considerable portions of the human body have been consumed, apparently by fire, the victim being found dead, or incapable of explaining the occurrence. Hence, the theory has been current that, under certain conditions, the tissues of the body might become self-ignited; and the fact that this so-called _spontaneous combustion_ has ordinarily taken place in those who had been addicted to the use of alcoholic drinks, has given a color of probability to the opinion. It has been supposed that the flesh of these unfortunate persons becoming saturated with the inflammable properties of the alcohol thus taken into the {146} system, took fire upon being exposed to a flame, as of a lighted candle, or, indeed, without any external cause. But, whether this be possible or not, one thing is certain, this strange kind of combustion has never been actually witnessed by any one competent to give a satisfactory account of it. 52. The results that have been observed may be satisfactorily explained by the accidental ignition of the clothes, or other articles near the body, and by the supposition that the individual was at the time too much stupefied by intoxication, to notice the source of danger, and provide for his safety. The highest temperature that has been observed in the body, about 112° Fahrenheit, is too low to ignite the vapor of alcohol; much less will it cause the burning of animal tissues. It is undoubtedly true that when the tissues are filled with alcohol, combustion will more easily take place than when the body is in a normal state; but, under any condition, the combustion of the body requires a higher degree of heat than can be generated by the body itself, or the mere _proximity_ of a lighted candle, or any cause of a similar character. {147} QUESTIONS FOR TOPICAL REVIEW. PAGE 1. What is the object of respiration? 123 2. What are the special organs of respiration? 123 3. In what organs does a change in the blood take place? 123 4. What is the nature of the change? 123, 133 5. Where are the lungs situated, and what is the character of the substance of which they are composed? 123, 125 6. Describe the facilities provided for the lung movements. 124 7. Describe the trachea, or windpipe. 124, 125, 127, 128 8. Describe the bronchial tubes, and their uses. 125, 126 9. What can you state in relation to the epiglottis? 126, 127 10. What are the cilia and what use do they probably serve? 128 11. How may the lungs be affected by not being properly protected? 128 12. Describe the movements necessary to the act of perfect respiration. 128, 129 13. What is the diaphragm, and what is its office? 128, 129 14. How may the organs of respiration be so improved as to increase their capacity and power? 129, 137 15. What is stated in relation to the frequency of respiration? 129, 130 16. To what extent may the act of respiration be subjected to our wills? 130 17. What may be said to be the capacity of the lungs? 130, 131 18. How long does it take every particle of air in the lungs to be expelled and new air to take its place? 130 19. What would be the consequences, if the entire capacity of the lungs were constantly used? 130, 131 20. What would be the consequences to a fish put into water from which the air had been completely exhausted? Why? 131 21. What is the air, and what are its parts? 131, 136, 138 22. What is the character of the air that has been just breathed? 132 23. Why is it that such air is not fit for respiration? 132, 139 24. What are the effects, as recorded in notable cases, of confinement in places the air of which has been breathed "over and over?" 133 25. What can you state of changes in the blood from respiration? 133 26. What of the air, as an article of food? 133, 134 27. What, on the subject of interchange of gases in the lungs? 134 28. Explain the difference between arterial and venous blood. 134, 135 29. Explain, if you can, the cause of the difference. 135 30. State what you can in relation to blue blood. 135 31. In relation to the amount of labor exerted in respiration. 135, 136 32. In relation to the deleterious properties of different gases. 136, 137 33. In relation to the dust that floats in the air. 137, 138 34. What are the properties of carbonic acid gas? 132, 138, 141 35. In what places is carbonic acid gas commonly found? 132, 138, 139 36. Describe the effects of carbonic acid gas. 132, 138, 139, 141 37. What are the general effects of breathing any impure atmosphere? 139, 140 38. What are Nature's provisions for purifying the air? 141, 142 39. What hints and directions are given on the subject of ventilation? 142, 143 40. How does the temperature of the body compare with the medium in which it lives? 143 41. How is temperature of the body regulated and sustained? 143, 144, 145 42. State what you can on the subject of spontaneous combustion. 145, 146 * * * * * {148} CHAPTER IX. THE NERVOUS SYSTEM. _Animal and Vegetative Functions--Sensation, Motion, and Volition--The Structure of the Nervous System--The White and Gray Substances--The Brain--Its Convolutions--The Cerebellum--The Spinal Cord and its System of Nerves--The Anterior and Posterior Roots--The Sympathetic System of Nerves--The Properties of Nervous Tissue--Excitability of Nervous Tissues--The Functions of the Spinal Nerves and Cord--The Direction of the Fibres of the Cord--Reflex Activity, and its Uses--The Functions of the Medulla Oblongata and the Cranial Ganglia--The Reflex Action of the Brain._ [Sidenote: 1. What processes are known as the vegetative functions? Why so called? What properties and functions does the plant possess? Their object?] 1. ANIMAL FUNCTIONS.--The vital processes which we have been considering, in the three previous chapters, of digestion, circulation, and respiration--belong to the class of functions known as _vegetative_ functions. That is, they are common to vegetables as well as animals; for the plant, like the animal, can originate nothing, not even the smallest particle of matter; and yet it grows, blossoms, and bears fruit, by reason of obtaining and digesting the nutriment which the air and soil provide. The plant has its circulatory fluid and channels, by which the nutriment is distributed to all its parts. It has, also, a curious apparatus in its foliage, by which it abstracts from the air those gaseous elements so necessary to its support; and thus it accomplishes vegetable respiration. These vegetative functions have their beginning and end within the organism of the plant; and their object is the preservation of the plant itself, as well as of the entire species. [Sidenote: 2. What second set of powers has the animal? What functions are mentioned? The advantage they give?] 2. The animal, in addition to these vegetative functions, has another set of powers, by the use of which he becomes conscious of a world external to himself, and brings {149} himself into active relations with it. By means of the vegetative processes, his life and species are maintained; while, by means of certain animal functions, he feels, acts, and thinks. These functions, among which are sensation, motion, and volition, not only distinguish the animal from the plant, but, in proportion to their development, elevate one creature above another; and it is by virtue of his pre-eminent endowment, in these respects, that man holds his position at the head of the animal creation. [Sidenote: 3. Animals whose structure is simple? As we approach man? Dependence of the animal functions of man?] 3. Among animals whose structure is very simple, the hydra, or fresh-water polyp, being an example, no special organs are empowered to perform separate functions; but every part is endowed alike, so that if the animal be cut into pieces, each portion has all the properties of the entire original; and, if the circumstances be favorable, each of the pieces will soon become a complete hydra. As we approach man, in the scale of beings, we find that the organs multiply, and the functions become more complete. The function of motion, the instruments of which--the muscles and bones--have been considered in former chapters, and all the other animal functions of man, depend upon the set of organs known as the nervous system. [Sidenote: 4. The nervous tissues, of what composed? When examined by the aid of the microscope? The white substance? The gray substance?] 4. THE NERVOUS SYSTEM.--The intimate structure of this system differs from any tissue which we have before examined. It is composed of a soft, pulpy substance, which, early in life, is almost fluid, but which gradually hardens with the growth of the body. When examined under the microscope, it is found to be composed of two distinct elements:--(1) the white substance, composing the larger proportion of the nervous organs of the body, which is formed of delicate cylindrical filaments, about 1/6000 of an inch in diameter, termed the nerve-fibres; and (2) the gray substance, composed of grayish-red, or {150} ashen-colored cells, of various sizes, generally possessing one or more off-shoots, which are continuous with the nerve-fibres just mentioned. [Sidenote: 5. Nervous centres and ganglia? Nerves? What do they serve? Cerebro-spinal system?] 5. The gray, cellular substance constitutes the larger portion of those important masses, which bear the name of _nervous centres_ and _ganglia_ (from _ganglion_, a knot), and in which all the nerve-fibres unite. These white nerve-fibres are found combined together in long and dense cords, called _nerves_ (from _neuron_, a cord), which serve to connect the nervous centres with each other, and to place them in communication with all the other parts of the body which have sensibility or power of motion. That part of the nervous system which is concerned in the animal functions, comprises the brain, the spinal cord, and the nerves which are derived therefrom; these are, together, called the _cerebro-spinal_ system (Fig. 40); while that other set of organs, which presides over, and regulates the vegetative functions, is called the sympathetic system of nerves. [Sidenote: 6. Location of the brain? Its weight? Its shape? Of what it consists? What organs at the base?] 6. THE BRAIN.--The brain is the great volume of nervous tissue that is lodged within the skull. It is the largest and most complex of the nervous centres, its weight, in the adult, being about fifty ounces, or one-fortieth of that of the whole body. The shape of the brain is oval, or egg-shaped, with one extremity larger than the other, which is placed posteriorly in the skull, to the concavity of which it very closely conforms. The brain consists chiefly of two parts; the _cerebrum_, or brain proper, and the _cerebellum_, or "little brain." In addition to these, there are several smaller organs at the base, among which is the commencement or expansion of the spinal cord, termed the _medulla oblongata_, or oblong marrow. {151} [Illustration: FIG. 40.--THE CEREBRO-SPINAL SYSTEM.] {152} [Sidenote: 7. The tissue of the brain? What, therefore, is required? Blows on the head? Membranes of the brain? Blood sent to the brain?] 7. The tissue of the brain is soft and easily altered in shape by pressure; it therefore requires to be placed in a well-protected position, such as is afforded by the skull, or _cranium_, which is strong without being cumbrous. In the course of an ordinary lifetime, this bony box sustains many blows, with little inconvenience; while, if they fell directly upon the brain, they would at once, and completely, disorganize that structure. Within the skull, the brain is enveloped by certain membranes, which at once protect it from friction, and furnish it with a supply of nutrient vessels; they are called the _arachnoid_, or "spider's web," the _dura mater_ and the _pia mater_, or the "tough" and "delicate coverings." The supply of blood sent to the brain is very liberal, amounting to one-fifth of all that the entire body possesses. The brain of man is heavier than that of any other animal, except the elephant and whale. [Sidenote: 8. Size of the brain proper? How divided? The exterior of the hemispheres? The interior?] 8. THE CEREBRUM.--The brain proper, or _cerebrum_, is the largest of the intracranial organs, and occupies the entire upper and front portion of the skull. It is almost completely bisected, by a fissure, or cleft, running through it lengthwise, into two equal parts called _hemispheres_. The exterior of these hemispheres is gray in color, consisting chiefly of nerve-cells, arranged so as to form a layer of gray matter one-fifth of an inch in thickness, and is abundantly supplied with blood-vessels. The interior of the brain, however, is composed almost wholly of white substance, or nerve-fibres. [Sidenote: 9. The surface of the cerebrum, how marked? The gray matter of the surface? Extent of the entire brain surface? Source of nervous power? What further?] 9. The surface of the cerebrum is divided by a considerable number of tortuous and irregular furrows, about an inch deep, into "convolutions," as shown in Fig. 41. Into these furrows the gray matter of the surface is extended, and, in this manner, its quantity is vastly increased. The extent of the entire surface of the brain, {153} with the convolutions unfolded, is computed to be equal to four square feet; and yet it is easily enclosed within the narrow limits of the skull. When it is stated that the gray matter is the true source of nervous power, it becomes evident that this arrangement has an important bearing on the mental capacity of the individual. And it is noticed that in children, before the mind is brought into vigorous use, these markings or furrows on the surface are comparatively shallow and indistinct; the same fact is true of the brain in the less civilized races of mankind and in the lower animals. It is also noticeable, that among animals, those are the most capable of being educated which have the best development of the cerebrum. [Illustration: FIG. 41.--UPPER SURFACE OF THE CEREBRUM. A, Longitudinal Fissure. B, The Hemispheres.] [Sidenote: 10. Location of the "little brain?" How divided? Its surface and interior? Its subdivisions? Its size?] 10. THE CEREBELLUM.--The "little brain" is placed beneath the posterior part of the cerebrum, and, like the latter, is divided into hemispheres. Like it, also, the surface of the cerebellum is composed of gray matter, and its interior is chiefly white matter. It has, however, no convolutions, but is subdivided by many crescentic, parallel ridges, which, sending down gray matter deeply into the {154} white, central portion, gives the latter a somewhat branched appearance. This peculiar appearance has been called the _arbor vitæ_, or the "tree of life," from the fact that when a section of the organ is made, it bears some resemblance to the trunk and branches of a tree (Fig. 42, F). In size, this cerebellum, or "little brain," is less than one-eighth of the cerebrum. [Illustration: FIG. 42.--VERTICAL SECTION OF THE BRAIN. A, Left Hemisphere of Cerebrum. B, Corpus Callosum. C, Optic Thalamus. D, The Pons Varolii. E, Upper extremity of the Spinal Cord. F, The Arbor Vitæ.] [Sidenote: 11. Medulla oblongata? Cranial nerves? Their shape and position?] 11. From the under surface of the cerebrum, and from the front margin of the cerebellum, fibres collect together to form the _medulla oblongata_ (Fig. 43, MA), which, on issuing from the skull, enters the spinal column, and then becomes known as the spinal cord. From the base of the brain, and from the sides of the medulla originate, also, the _cranial nerves_, of which there are twelve pairs. These nerves are round cords of glistening white appearance, and, {155} like the arteries, generally lie remote from the surface of the body, and are well protected from injury. [Illustration: FIG. 43.--THE BASE OF THE BRAIN.] [Sidenote: 12. The spinal cord? Of what composed? How divided? Each half?] 12. THE SPINAL CORD.--The spinal cord, or "marrow," is a cylindrical mass of soft nervous tissue, which occupies a chamber, or tunnel, fashioned for it in the spinal column (Fig. 44). It is composed of the same substances as the brain; but the arrangement is exactly reversed, the white matter encompassing or surrounding the gray matter instead of being encompassed by it. The amount of the white substance is also greatly in excess of the other material. A vertical fissure partly separates the cord into two lateral halves, and each half is composed of two separate bundles of fibres, which are named the anterior and posterior columns. {156} [Illustration: FIG. 44. A, Cerebrum. B, Cerebellum. D, D, Spinal Cord.] [Sidenote: 13. Uses of these columns? Importance of this part of the nervous system? How protected?] 13. These columns have entirely different uses, and each of them unites with a different portion of the nerves which have their origin in the spinal cord. The importance of this part of the nervous system is apparent from the extreme care taken to protect it from external injury. For, while a very slight disturbance of its structure suffices to disarm it of its power, yet so staunch is its bony enclosure, that only by very severe injuries is it put in peril. The three membranes that cover the brain are continued downward so as to envelope and still further shield this delicate organism. [Sidenote: 14. The spinal nerves? The posterior root? The nerves, how arranged? Their office?] 14. THE SPINAL NERVES.--The spinal nerves, thirty-one pairs in number, spring from each side of the cord by two roots, an anterior and a posterior root, which have the same functions as the columns bearing similar names. The posterior root is distinguished by possessing a ganglion of gray matter, and by a somewhat larger size. The successive points of departure, or the off-shooting of these nerves, occur at short and nearly regular intervals along the course of the spinal cord. Soon after leaving these points, {157} the anterior and posterior roots unite to form the trunk of a nerve, which is distributed, by means of branches, to the various organs of that part of the body which this nerve is designed to serve. The spinal nerves supply chiefly the muscles of the trunk and limbs and the external surface of the body. [Sidenote: 15. The nerve tissue? Its character? Course of each nerve fibre?] 15. The tissue composing the nerves is entirely of the white variety, or, in other words, the nerve-fibres; the same as we have observed forming a part of the brain. But the nerves, instead of being soft and pulpy, as in the case of the brain, are dense in structure, being hardened and strengthened by means of a fibrous tissue which surrounds each of these delicate fibres, and binds them together in glistening, silvery bundles. Delicate and minutely fine as are these nerve-fibres, it is probable that each of them pursues an unbroken, isolated course, from its origin, in the brain or elsewhere, to that particular point which it is intended to serve. For, although their extremities are often only a hair's breadth distant from each other, the impression which any one of them communicates is perfectly distinct, and is referred to the exact point whence it came. [Sidenote: 16. How may we illustrate the fact? The fibre connecting the brain with a point in the foot?] 16. This may be illustrated in a simple manner, thus: if two fingers be pressed closely together, and the point of a pin be carried lightly across from one to the other, the eyes may be closed, and yet we can easily note the precise instant when the pin passes from one finger to the other. If the nerve-fibres were less independent, and if it were necessary that they should blend with and support each other, all accuracy of perception would be lost, and all information thus afforded would be pointless and confused. These silvery threads must, therefore, be spun out with an infinite degree of nicety. Imagine, for instance, the fibre which {158} connects the brain with some point on the foot,--its length cannot be less than one hundred thousand times greater than its diameter; and yet it performs its work with as much precision as fibres that are comparatively much stronger and less exposed. [Sidenote: 17. The sympathetic system of nerves? Of what does it consist?] 17. THE SYMPATHETIC SYSTEM.--The _sympathetic system_ of nerves remains to be described. It consists of a double chain of ganglia, situated on each side of the spinal column, and extending through the cavities of the trunk, and along the neck into the head. These ganglia are made up for the most part of small collections of gray nerve-cells, and are the nerve-centres of this system. From these, numerous small nerves are derived, which connect the ganglia together, send out branches to the cranial and spinal nerves, and form networks in the vicinity of the stomach and other large organs. A considerable portion of them also follows the distribution of the large and small blood-vessels, in which the muscular tunic appears. Branches also ascend into the head, and supply the muscles of the eye and ear, and other organs of sense. [Sidenote: 18. Association of the various regions of the body? If one member suffers? Blushing?] 18. In this manner, the various regions of the body are associated with each other by a nervous apparatus, which is only indirectly connected with the brain and spinal cord; and thus it is arranged that the most widely separated organs of the body are brought into close and active sympathy with each other, so that, "if one member suffers, all the other members suffer with it." From this fact, the name _sympathetic system_, or the _great sympathetic nerve_, has been given to the complicated apparatus we have briefly described. Blushing and pallor are caused by mental emotions, as modesty and fear, which produce opposite conditions of the capillaries of the face by means of these sympathetic nerves. {159} [Sidenote: 19. Properties of nervous tissue? Office of the gray substance? Of the white? The nervous centres? White fibres?] 19. THE PROPERTIES OF NERVOUS TISSUE.--We have seen that in all parts of this system, there are only two forms of nervous tissue; namely, the gray substance and the white substance, so called from their difference of color as seen by the naked eye; or the nerve-cell, and the nerve-fibre, so called from their microscopic appearance. Now these two tissues are not commonly mingled together, but either form separate organs, or distinct parts of the same organs. This leads us to the conclusion that their respective uses are distinct. And this proves to be the simple fact; wherever we find the gray substance, we must look upon it as performing an active part in the system, that is, it originates nervous impulses; the white matter, on the contrary, is a passive agent, and serves merely as a conductor of nervous influences. Accordingly, the nervous centres, composed so largely of the gray cells, are the great centres of power, and the white fibres are simply the instruments by which the former communicate with the near and distant regions of the body under their control. [Sidenote: 20. What comparison is made between the brain and the nation's capitol? The vital property, excitability? What example is given?] 20. We may compare the brain, then, to the capital, or seat of government, while the various ganglia, including the gray matter of the cord, like so many subordinate official posts, are invested with authority over the outlying provinces; and the nerves, with the white matter of the cord, are the highways over which messages go and return between these provinces and the local or central governments. But both forms of nervous tissue possess the same vital property, called excitability; by which term is meant, that when a nerve-cell or fibre is stimulated by some external agent, it is capable of receiving an impression and of being by it excited into activity. A ray of light, for example, falling upon one extremity of a fibre in the eye, excites it throughout its whole length; and its {160} other extremity, within the brain, communicating with a nerve-cell, the latter, in its turn, is excited, and the sensation of sight is produced. [Sidenote: 21. Change in the nervous tissues? Nerve force and electricity?] 21. What sort of change takes place in the nervous tissue when its excitability is aroused, is not known; certainly none is visible. On this account, it has been thought by some, that the nerve-fibre acts after the manner of a telegraph wire; that is, it transmits its messages without undergoing any material change of form. But, though the comparison is a convenient one, it is far from being strictly applicable; and the notion that nerve-force is identical with electricity has been fully proved to be incorrect. [Sidenote: 22. Functions of the nerves? In the case of the nerve of a living animal? Of the human body?] 22. THE FUNCTIONS OF THE NERVES.--The nerves are the instruments of the two grand functions of the nervous system, Sensation and Motion. They are not the true centres of either function, but they are the conductors of influences which occasion both. If the nerve in a limb of a living animal be laid bare, and irritated by pinching, galvanizing, or the like, two results follow, namely: the animal experiences a sensation, that of pain, in the part to which the nerve is distributed, and the limb is thrown into convulsive action. When a nerve in a human body is cut by accident, or destroyed by disease, the part in which it ramifies loses both sensation and power of motion; or, in other words, it is paralyzed. We accordingly say that the nerves have a twofold use, a _sensory_ and _motor_ function. [Sidenote: 23. If an exposed nerve be divided? What is proved? The course of the sensory set of fibres? Of the motor set? To what are they likened?] 23. If a nerve that has been exposed be divided, and the inner end, or that still in connection with the nerve-centres, be irritated, sensation is produced, but no movement takes place. But if the outer end, or that still connected with the limb, be irritated, then no pain is felt, but {161} muscular contractions are produced. Thus we prove that there are two distinct sets of fibres in the nerves; one of which, the _sensory_ fibres, conduct toward the brain, and another, the _motor_ fibres, conduct to the muscles. The former may be said to begin in the skin and other organs, and end in the brain; while the latter begin in the nervous centres and end in the muscles. They are like a double line of telegraph wires, one for inquiries, the other for responses. [Sidenote: 24. The two roots of the spinal nerves? What has been found? Difference of the two sorts of fibres? Result of their union?] 24. We have already spoken of the two roots of the spinal nerves, called from their points of origin in the spinal cord, the anterior and posterior roots. These have been separately cut and irritated in the living animal, and it has been found that the posterior root contains only sensory fibres, and the anterior root has only motor fibres. So that the nerves of a limb may be injured in such a way that it will retain power of motion and yet lose sensation; or the reverse condition, feeling without motion, may exist. Between these two sorts of fibres, no difference of structure can be found; and where they have joined to form a nerve it is impossible to distinguish one sort from the other. [Sidenote: 25. Transient paralysis? When such is the case with the leg? What other fact is observed?] 25. Occasionally a nerve is so compressed as to be temporarily unable to perform its functions: a transient paralysis then takes place. This is the case when the leg or arm "gets asleep," as it is expressed. When such is the condition with the leg, and the person suddenly attempts to walk, he is liable to fall, inasmuch as the motor fibres cannot convey orders to the muscles of the limb. Another fact is observed: there is no sensation in this nerve at the point of its compression; but the whole limb is numb, and tingling sensations are felt in the foot, the point from which the sensory fibres arise. [Sidenote: 26. What does this illustrate? Sensation? The feeling after a limb has been amputated? Striking of the "funny bone?"] 26. This illustrates the manner in which the brain {162} interprets all injuries of the trunk of a nerve. Sensation or pain is not felt at the point of injury, but is referred to the outer extremities of the nerve, where impressions are habitually received. This is the reason why, after a limb has been amputated by the surgeon, the patient appears to suffer pain in the member that has been severed from the body; while some form of irritation at the end of the nerve in the wound, or stump, is the real source of his distress. Again, when the "funny-bone"--that is, the ulnar nerve at the elbow,--is accidentally struck, the tingling sensations thus produced are referred to the outer side of the hand and the little finger, the parts to which that nerve is distributed. [Sidenote: 27. The spinal nerves, and two from the brain? Of the remainder? Difference in the nerves? How accounted for? The rate of conduction along a nerve? As compared with electricity?] 27. All the spinal nerves, and two from the brain, are concerned in both sensation and motion. Of the remainder of the cranial nerves, some are exclusively motor, others exclusively sensory; and still others convey, not ordinary sensations, but special impressions, such as sight, hearing, and smell, which we have yet to consider. However much the functions of the nerves seem to vary, there is but little difference discoverable in the nerves themselves, when examined under the microscope. Whatever difference exists must be accounted for in consequence of the nerves communicating with different portions of the gray matter of the brain. The rate of motion of a message, to or from the brain along a nerve, has been measured by experiment upon the lower animals, and estimated in the case of man at about two hundred feet per second. As compared with that of electricity, this is a very slow rate, but, in respect to the size of the human body, it is practically instantaneous. [Sidenote: 28. Functions of the anterior and posterior columns of the cord? If the cord be divided?] 28. THE FUNCTIONS OF THE SPINAL CORD.--As the {163} anterior and posterior roots of the spinal nerves have separate functions, so the anterior and posterior columns of the cord are distinct in function. The former are concerned in the production of motion, the latter in sensation. If the cord be divided, as before in the case of the nerve, it is found that the parts below the point of injury are deprived of sensation and of the power of voluntary motion on both sides of the body, a form of paralysis which is called _paraplegia_. [Sidenote: 29. Paraplegia? Result and danger to life? When the injury occurs in the neck?] 29. This form of disease, paraplegia, is sometimes seen among men, generally as the result of a fall, or some other severe accident, by which the bones of the spine are broken, and the cord is crushed, or pierced by fragments of bone. The parts which are supplied by nerves from the cord above the point of injury are as sensitive and mobile as before. The results are similar, whether the division happens at a higher or lower portion of the spinal cord; but the danger to life increases proportionally as the injury approaches the brain. When it occurs in the neck, the muscles of inspiration are paralyzed, since they are supplied by nerves issuing from that region; and as a result of this paralysis, the lungs are unable to act, and life is speedily brought to a close. [Sidenote: 30. Experiment of cutting the spinal cord of an animal? What inference is drawn?] 30. When the spinal cord of an animal has been cut, in experiment, it may be irritated in a manner similar to that alluded to when considering the nerves. If, then, the upper cut surface be excited, it is found that pain, referable to the parts below the cut, is produced; but when the lower cut surface is irritated, no feeling is manifested. So we conclude that in respect to sensation, the spinal cord is not its true centre, but that it is merely a conductor, and is therefore the great sensory nerve of the body. When the lower surface of the cut is irritated, the muscles of the {164} parts below the section are violently contracted. Hence, we conclude that, in respect to the movements ordered by the will, the spinal cord is not their source; but that it acts only as a conductor, and is, accordingly, the great motor nerve of the body. [Sidenote: 31. What singular fact is noticed? What does the result show?] 31. DIRECTION OF THE FIBRES OF THE CORD.--If one lateral half of the spinal cord be cut, or injured, a very singular fact is observed. All voluntary power over the muscles of the corresponding half of the body is lost, but the sensibility of that side remains undiminished. This result seems to show that the motor fibres of the cord pursue a direct course, while its sensory fibres are bent from their course. And this has been proved to be the fact; for immediately after the posterior roots--the conductors of sensory impressions--join the posterior columns, they enter the gray matter of the cord, and passing over, ascend to the brain on the opposite side. Accordingly, the sensory fibres from the right and left sides interlace each other in the gray matter; this arrangement has been termed the _decussation_, or crossing of these fibres. This condition serves to explain how a disease or injury of the cord may cause a paralysis of motion in one leg, and a loss of sensation in the other. [Sidenote: 32. Direction of the anterior or motor columns? In the cord itself? In the medulla oblongata? The decussation?] 32. The direction of the anterior, or motor columns of the cord, is downward from the brain. In the cord itself, the course of the motor fibres is for the most part, a direct one; but in the medulla oblongata, or upper extremity of the cord, and therefore early in their career, these fibres decussate, or cross from side to side in a mass; and not separately, as in the case of the posterior fibres just mentioned. This arrangement is termed the _decussation_ of the anterior columns of the medulla. [Sidenote: 33. Result of the double interlacing of fibres? Where is the seat of pain when the right hand is hurt? The moving of the foot? Loss of sensation in one side of the body?] 33. From this double interlacing of fibres results a {165} crossed action between the original and terminal extremity of all nerve-fibres which pass through the medulla; namely, those of all the spinal nerves. Consequently, if the right hand be hurt, the left side of the brain feels the pain; and if the left foot move, it is the right hemisphere which dictates its movement. For the same reason, when a loss of sensation and power of motion affecting the right side of the body alone is observed, the physiologist understands that the brain has been invaded by disease upon its left side. This affection is termed _hemiplegia_, or the "half-stroke." The full-stroke, which often follows the rupture of a blood-vessel in the brain, is commonly called _paralysis_. [Sidenote: 34. What other important use has the cord? What is the activity denominated?] 34. THE REFLEX ACTION OF THE CORD.--We have already considered the cord as the great motor and sensory nerve of the body, but it has another and extremely important use. By virtue of the gray matter, which occupies its central portion, it plays the part of an independent nerve centre. The spinal cord not only conducts some impressions to the brain, but it also arrests others; and, as it is expressed, "reflects" them into movements by its own power. This mode of nervous activity is denominated the _Reflex Action_ of the cord. [Sidenote: 35. Example of the fowl? Centipede? Frog? What do they prove?] 35. A familiar example of this power of the cord is found in the violent movements which agitate a fowl after its head has been cut off. The cold-blooded animals also exhibit reflex movements in an astonishing degree. A decapitated centipede will run rapidly forward, and will seemingly strive to overturn, or else climb over obstacles placed in its way. A frog similarly mutilated will sustain its headless body upon its feet, in the standing posture, just as it might do if it were still alive. If pushed over, it will regain its feet; and if the feet are irritated, it will {166} jump forward. There can be no doubt that, in the lower animals, movements may take place which are completely divorced from the will, sensation, and consciousness; for in those animals, as well as in man, these faculties have their principal seat within the brain. [Sidenote: 36. What is necessary in most cases to awaken reflex movements? In the case of the fowl? Convulsions which follow decapitation?] 36. An irritation is necessary, in most instances, to awaken reflex movements. In the case of the decapitated fowl, its muscles are excited to convulsive action by reason of its being thrown upon the hard ground and roughly handled. Let it be treated differently, and the convulsions will not take place: let it be laid gently upon soft cotton, and the body will remain comparatively quiet. It may comfort some people to know that the convulsions which follow decapitation are not attended with pain; nor are they a necessary part of the "act of death," as some suppose. [Sidenote: 37. Actions in the human body distinct from voluntary efforts?] 37. In the human body, likewise, actions are excited that are entirely distinct from the ordinary voluntary efforts. It is not permissible, desirable, nor even necessary to decapitate a man that the body may be disconnected from his brain, in order to test the effect of irritation upon the spinal cord; although the bodies of beheaded criminals have been experimented upon, and caused to move by powerful galvanic batteries. The resort to such means of experiment is rendered unnecessary by the occurrence of certain deplorable cases of disease and injury, which effectually sever all communication between the brain and a large part of the body. [Sidenote: 38. Reflex action after injury of the cord? Why not due to the muscles?] 38. Thus, the cord may be so far injured, as the result of accident, as to terminate all sensation and voluntary motion in the lower half of the body, the patient seemingly becoming lifeless and powerless from the waist downward. And yet, by tickling or pinching either foot, the leg {167} of the same side may be made to jerk, or even to kick with considerable force; but, unless the patient is observing his limbs, he is wholly unconscious of these movements, which are, therefore, performed independently of the brain. And they are in nowise due to the muscles of the limb; for, if the cord itself becomes diseased below the point of injury, the muscles cease to contract. [Sidenote: 39. What are the requisites for the production of this form of nervous action?] 39. For the production of this form of nervous action three things are requisite--(1) a nerve to conduct messages from the surface of the body, one of that variety formerly described as sensory, but which are now incapable of awakening sensation; (2) a portion of uninjured spinal cord which shall reflect or convert impressions into impulses; and (3) a motor nerve to conduct impulses outward to the muscles. The power of the cord to enforce reflex acts resides in the gray matter, into which the reflex nerves enter and from which they depart, by means of their posterior and anterior roots respectively. [Sidenote: 40. Why do we not readily recognize the reflex activity of the cord in our own bodies? How best studied in others? Example?] 40. THE USES OF THE REFLEX ACTION.--The reflex activity of the cord is exhibited in the healthy body in many ways, but since it is never accompanied with sensation, we do not readily recognize it in our own bodies. Reflex movements are best studied in the cases of other persons, when the conditions enable us to distinguish between acts that are consciously, and those that are unconsciously performed. For example, if the foot of a person soundly asleep be tickled or pinched, it will be quickly withdrawn from the irritation. [Sidenote: 41. Similar movements? Arm of a person? Melted wax or heated coin on the hand?] 41. Similar movements may be observed in cases where the consciousness and sensation are temporarily obliterated by disease, or by means of narcotic poisons. If the arm of a person who has been rendered insensible by {168} chloroform, be raised, and then allowed to fall, it will be noticed that the limb does not drop instantly, like a lifeless member, but a certain amount of rigidity remains in its muscles, which resists or breaks the force of its descent. Again, when a substance like melted sealing-wax, or a heated coin, falls upon the hand, the limb is snatched away at once, even before the feeling of pain has been recognized by the brain. When jolted in a rapidly moving car, we involuntarily step forward or backward, so as to preserve the centre of gravity of the body. [Sidenote: 42. Result of healthful reflex activity? When may the reflex energy be deficient?] 42. These and similar acts are executed by the same mechanism as that previously described in the case of paralysis from an injury of the spinal cord. The muscles thus called into play, are those which are ordinarily under the sway of the will, but which in these cases act through this reflex action of the cord, altogether independently of the will. A healthful reflex activity produces an elasticity, or "tone," of the voluntary muscular system, which, in a great measure, explains the existence in the young and vigorous of a feeling of buoyancy and reserve power. Its possessor is restlessly active, and it may appropriately be said of him, "he rejoiceth as a strong man to run a race." But this reflex energy may be deficient. This is true when the blood is poor and wanting in its solid ingredients, or the circulation is feeble; the muscles, then, are flabby and weak, and the person himself is said to be "nerveless," or indisposed to exertion. Shivering from cold, and trembling from fear, may, in part, be referred to a temporary loss of tone, resulting from a powerful impression upon the brain. [Sidenote: 43. Excess of this activity in disease? Hydrophobia, etc.? The difference in severity of the convulsions?] 43. An excess of this activity may also be observed in disease. In this condition, the excitability of the cord is unnaturally aroused, and frequent and violent movements {169} of the limbs and body, called convulsions, are the result. The convulsions of young children, and the nervous agitation of _chorea_, or St. Vitus's dance, are reflex in character; as are also the symptoms attending poisoning by strychnine, and those terrible diseases, _tetanus_, or "locked jaw," and _hydrophobia_. The severity of the convulsions is not the same in all cases of these disorders; but, in those last mentioned the most violent spasmodic movements are provoked by the slightest form of irritation--such as the sound of pouring water, the sight of any glittering object, the glancing of a mirror, the contact of cool air, or even the touch of the bedclothes. [Sidenote: 44. Another variety of reflex motions? What are they? What is stated of the mind in connection with these movements?] 44. Another variety of reflex motions takes place in certain involuntary muscles, and over these the cord exercises supreme control. They are principally those movements which aid the performance of digestion and nutrition, the valve-action of the pylorus, and other movements of the stomach and intestines. In these movements the mind shares no part. And it is well that this is so; for since the mind is largely occupied with affairs external to the body, it acts irregularly, becomes fatigued, and needs frequent rest. The spinal cord, on the contrary, is well fitted for the form of work on which depends the growth and support of the body, as it acts uniformly, and with a machine-like regularity. [Sidenote: 45. Consciousness in these operations? Physical wants?] 45. These operations are not accompanied by consciousness; for, as a general rule, the attention is only called to them when they become disordered. Many a person does not know where his stomach is situated, until he discovers its position by reason of a feeling of distress within it, produced by giving that organ improper work to perform. In this manner the higher and nobler faculties of the mind are liberated from the simply routine duties of the {170} body; and we are thus left to direct the attention, the reason, and the will to the accomplishment of the great ends of our existence. If it were otherwise, we could only find time to attend to our ordinary physical wants. [Sidenote: 46. How many objects may the reflex activity be said to have? State the first. The second. The third.] 46. The objects of the reflex activity of the cord are threefold. In the first place, it acts as the protector of man, in his unconscious moments. It is his unseen guardian, always ready to act, never growing weary, and never requiring sleep. Nor does its faithful action wholly cease with the cessation of life in other parts. In the second place, it is the regulator of numerous involuntary motions that are necessary to the nutrition of the body. Here its actions are entirely independent of the brain, and are performed in a secret and automatic manner. And, thirdly, it acts as a substitute, and regulates involuntary movements in the muscles usually under the influence of the will. It thus takes the place of the higher faculties in performing habitual acts, and permits them to extend their operations more and more beyond the body and its material wants. [Sidenote: 47. How does the medulla oblongata resemble the cord?] 47. THE FUNCTIONS OF THE MEDULLA OBLONGATA.--The prolongation of the spinal cord, within the skull, has been previously spoken of as the medulla oblongata. It resembles the cord, in being composed of both white and gray matter, and in conducting sensory and motor influences. It likewise gives rise to certain nerves, which are here called cranial nerves (from _cranium_, the skull). All except two of these important nerves spring from the medulla, or the parts immediately adjoining it; the exceptions are the two nerves taking part in the special senses of sight and smell, which nerves have their origin at the base of the cerebrum. [Sidenote: 48. What final fact is observed in the crossing of the motor columns?] 48. The decussation, or crossing of the motor columns, has been previously described, when treating of the {171} direction of the nerve-fibres of the cord; and the singular fact has been alluded to, that when one side of the brain is injured, its effects are limited to the opposite side of the body. One more fact remains to be observed in this connection, namely, this crossed action does not usually take place in the cranial nerves. Accordingly, when apoplexy, or the rupture of a blood-vessel, occurs in the right hemisphere of the cerebrum, the left side of the body is paralyzed, but the right side of the face is affected; this is because that part of the body is supplied by the cranial nerves. [Sidenote: 49. The pneumogastric nerve? The feelings aroused by it? The "vital knot?"] 49. A portion of the medulla presides over the important function of respiration, and from it arises the _pneumogastric_ nerve, so called because its branches serve both the lungs and stomach. The feelings of hunger, thirst, and the desire for air are aroused by means of this nerve. The wounding of the gray matter of the medulla, even of a small portion of it, near the origin of the pneumogastric nerve, at once stops the action of the lungs and causes death. In consequence of the importance of this part, it has been termed the "vital knot." We find, also, that its location within the skull is exceedingly well protected, it being quite beyond the reach of any ordinary form of harm from without. [Sidenote: 50. The uses of the smaller gray masses at the base of the brain?] 50. THE FUNCTIONS OF THE CRANIAL GANGLIA.--The uses of the smaller gray masses lying at the base of the brain are not well ascertained; and, on account of their position, so remote from the surface, it would, at first, seem well-nigh impossible to study them. But, from the results following diseases in these parts, and from experiments upon inferior animals, they are becoming gradually better understood; and there is reason to believe that eventually the physiological office of each part will be clearly ascertained and defined. It is believed, however, but not {172} absolutely proven, that the anterior masses, like the anterior roots of the spinal nerves and the anterior columns of the cord, are concerned in the production of motion; in fact, that they are the central organs of that function. The posterior gray masses are, on the contrary, supposed to be the seat of sensation. [Sidenote: 51. Function of the cerebellum? When it is diseased?] 51. THE FUNCTION OF THE CEREBELLUM.--The function of the cerebellum, or "little brain," is the direction of the movements of the voluntary muscles. When this organ is the seat of disease or injury, it is usually observed that the person is unable to execute orderly and regular acts, but moves in a confused manner as if in a state of intoxication. Like the larger brain, or cerebrum, it appears to be devoid of feeling; but it takes no part in the operations of the mind. [Sidenote: 52. Where is the seat of the mind? The subordination of the other organs? The gray matter?] 52. THE FUNCTION OF THE CEREBRUM.--The cerebrum, or brain proper, is the seat of the mind; or, speaking more exactly, it is the material instrument by which the mind acts; and, as it occupies the highest position in the body, so it fulfils the loftiest uses. All the other organs are subordinate to it: the senses are its messengers, which bring it information from the outer world, and the organs of motion are its servants, which execute its commands. Here, as in the nervous apparatus of lower grade already considered, the gray matter is the element of power; and, in proportion as this substance increases in extent, and in proportion to the number of convolutions in the hemispheres, do the mental faculties expand. [Sidenote: 53. What is stated of men in connection with the size of their brain? With the brains of other animals?] 53. There have been a few, but only a few, men of distinguished ability whose brains have been comparatively small in size; the rule being that great men possess large brains. The relative weight of the brain of man, as {173} compared with the weight of the body, does not, in all instances, exceed that of the inferior animals; the canary and other singing-birds have a greater relative amount of nervous matter than man; but man surpasses all other creatures in the size of the hemispheres of the cerebrum, and in the amount of gray substance which they contain. [Sidenote: 54. Sensitiveness of the brain substance? The removal of a portion of the brain? State the remarkable case mentioned?] 54. It is a singular fact that this cerebral substance is insensitive, and may be cut without causing pain. The removal of a considerable quantity of the brain has taken place, as the result of accident, without causing death, and without even affecting seriously the intellect. A remarkable case of injury of the brain is recorded, in which, from the accidental explosion of gunpowder used in blasting a rock, the "tamping-iron" was driven directly through the skull of a man. This iron rod, three feet and seven inches long, an inch and a quarter in diameter, and weighing more than thirteen pounds, entered the head below the ear and passed out at the top of the skull, carrying with it portions of the brain and fragments of bone. The man sustained the loss of sight on one side, but otherwise recovered his health and the use of his faculties. Moreover, disease has occurred, compromising a large portion of the brain, without impairing the faculties of the mind, when the disease was limited to one side only. [Sidenote: 55. Thought, emotion, and will? What power do they give us?] 55. Impressions conveyed to the hemispheres from the external world arouse the mental operations called thought, emotion, and the will. These are the godlike attributes which enable man to subjugate a world, and afterward cause him to "sigh for other worlds to conquer;" which enable him to acquaint himself with the properties of planets millions of miles distant from him, and which give him that creative power by which he builds and peoples the new worlds of poetry and art. {174} [Sidenote: 56. Are the brain and the mind identical?] 56. All these mental acts, and many others, are developed through the action of the brain; not that the brain and the mind are the same, or that the brain secretes memory, imagination, or the ideas of truth and justice, as the stomach secretes the gastric juice. But rather, as the nerve of the eye, stimulated by the subtile waves of light, occasions the notion of color, so the brain, called into action by the mysterious influences of the immaterial soul, gives rise to all the intellectual, emotional, and voluntary activities of mankind. [Sidenote: 57. What do we know of the cerebrum and its powers?] 57. The cerebrum, according to our present knowledge of it, must be regarded as a single organ, which produces different results, according as it is acted upon by the immaterial mind in different ways. Recent investigations, however, seem to prove that the faculty of language is dependent upon a small part of the left hemisphere of the cerebrum, near the temple. At least, in almost every instance where this part is diseased, the patient can no longer express himself in speech and writing. [Sidenote: 58. The reflex function of the organs within the skull? The reflex power of the medulla? Respiration?] 58. THE REFLEX ACTION OF THE BRAIN.--The reflex function of the organs within the skull is very active and important. Like that of the cord, it protects the body by involuntary movements, it regulates the so-called vegetative acts, and it takes the place of the will in controlling the voluntary muscles, when the attention is turned in other directions. The reflex power of the medulla governs the acts of respiration, which are absolutely and continuously essential to life. Respiration is, as we have seen, partly under the influence of the will; but this is due in part to the fact that respiration is indirectly concerned in one of the animal functions, that of speech. [Sidenote: 59. What else does reflex action occasion? Winking? Other examples?] 59. Reflex action also occasions coughing and sneezing, {175} whenever improper substances enter the air-passages. Winking is an act of the same sort, and serves both to shield the eyes from too great glare of light, and to preserve them by keeping the cornea moist. Looking at the sun or other strong light, causes sneezing by reflex action. Laughing, whether caused by tickling the feet or by some happy thought, and also sobbing, are reflex acts, taking place by means of the respiratory muscles. [Sidenote: 60. Muscles called into play by certain reflex movements? The somnambulist?] 60. Certain of the protective reflex movements call into play a large number of muscles, as in the balancing of the body when walking along a narrow ledge, or on a slippery pavement. The dodging motion of the recruit, when the first cannon ball passes over his head, is reflex and involuntary. The fact that these involuntary, reflex acts are performed with great precision, will explain why it is that accidents seldom befall the somnambulist, or sleep-walker, although he often ventures in most perilous places. [Sidenote: 61. What is said of walking and other acts in connection with the office performed by the medulla and spinal cord?] 61. Walking, sitting, and other acts of daily life, become automatic, or reflex, from habit: the mind is seldom directed to them, but delegates their control to the medulla and spinal cord. Thus a person in walking, may traverse several miles while absorbed in thought, or in argument with a companion, and yet be conscious of scarcely one in a thousand of the acts that have been necessary to carry his body from one point to another. By this admirable and beautiful provision, the mind is released from the charge of the ordinary mechanical acts of life, and may devote itself to the exercise of its nobler faculties. And it is worthy of notice, that the greater the use of these faculties, the more work does the reflex function assume and perform; and thus the employment of the one insures the improvement of the other. {176} QUESTIONS FOR TOPICAL REVIEW. PAGE 1. State fully what is meant by the term vegetable function. 148 2. To what is man indebted for his position as the head of the animal creation? 148, 149 3. What can you state on the subject of special organs for separate functions? 149 4. Describe, as fully as you can, the structure of the nervous system. 149, 150 5. Describe the brain, its location, size, shape, and structure. 150, 152 6. Describe the brain proper, or cerebrum. 152, 153, 174 7. What connection is noticed between the cerebrum and mental power? 153, 172, 174 8. Describe the little brain, or cerebellum. 153, 154, 172 9. Describe the spinal cord. 154, 155, 156 10. What are the spinal nerves, and how are they arranged? 156, 157 11. What is the character and substance of their tissues? 157 12. State how the nerve-fibres perform their office, and give the illustration. 157, 158 13. Describe the sympathetic system of nerves. 158 14. State what is meant by the properties of nervous tissue, and give the illustration. 159, 160 15. Explain what is meant by the functions of the nerves, and give the illustration. 160, 161, 162 16. What is meant by a transient paralysis of a nerve? Give the illustration. 161, 162 17. What can you state of the rate of message-motion along a nerve? 162 18. What are the functions of the spinal cord? 162, 163, 164, 165 19. State what you can of the form of paralysis known as paraplegia. 163 20. What experiments, with results, upon the spinal cord are noted? 163, 164 21. Explain how injury of the cord may produce paralysis of motion in one leg, and at the same time a loss of sensation in the other. 164 22. Explain how, if the right hand be hurt, the left side of the brain is made to feel the pain. 165 23. Now, explain as fully as you can the direction of the fibres of the cord. 164, 165 24. What is understood by the reflex action of the cord? 165 25. What experiments are mentioned to prove this power of the cord? 165, 166 26. What are the uses of the reflex action of the cord? 167-170 27. What illustrations are mentioned to show such uses? 167-170 28. What is the medulla oblongata? 154, 170 29. What are the functions of the medulla oblongata? 170, 171 30. What can you state of the functions of the cranial ganglia? 171, 172 31. What are the functions of the cerebellum? 172 32. What is the function of the cerebrum? 172, 174 33. In what way does the size of the brain generally indicate the character of the man? 172, 173 34. What facts show that the gray substance of the brain is insensitive? 173 35. Upon what does the faculty of language seem to depend? 174 36. What has been observed in support of this statement? 174 37. Of what importance is the reflex action of the brain? 174, 175 38. In what ways is this importance made manifest? 174, 175 * * * * * {177} CHAPTER X. THE SPECIAL SENSES. _The Production of Sensations--Variety of Sensations--General Sensibility--Pain and its Function--Special Sensation, Touch, Taste, Smell, Sight, and Hearing--The Hand, the Organ of Touch--The Sense of Touch--Delicacy of Touch--Sensation of Temperature and Weight--The Tongue the Organ of Taste--The Nerves of Taste--The Sense of Taste and its Relations with the other Senses--The Influence of Education on the Taste--The Nasal Cavities, or the organs of Smell--The Olfactory Nerve--The Uses of the Sense of Smell--The Sense of Sight--Light--The Optic Nerve--The Eyeball and its Coverings--The Function of the Iris--The Sclerotic, Choroid, and Retina--The Tears and their Function--The Movements of the Eyeball--The Function of Accommodation--The Sense of Hearing and Sound--The Ear, or the organ of Hearing--The External, Middle, and Internal Ear._ [Sidenote: 1. True centre of sensation? Place of the mind's impressions? What is it convenient to say? What further is stated?] 1. PRODUCTION OF SENSATIONS.--We have already seen that the true centre of sensation is some organ within the skull, probably among the gray masses at the base of the brain; but the mind never perceives impressions at that point; but, on the contrary, always refers them to the external organs of sensation. Hence, it is convenient to say, that those outer parts possess the property of sensibility. For instance, we say that we hear with the ear, taste with the tongue, and feel with the fingers. That this is not the exact truth is proven by the fact, that whenever the nerve connecting one of these organs with the brain is severed, it at once loses its capacity for sensation. [Sidenote: 2. Consciousness? During sleep? In profound insensibility?] 2. Consciousness, another faculty of the brain, is necessary to complete a sensation. During sleep, and in other unconscious states, the usual impressions are presented to {178} the ear, the nose, and the skin, but they fail to excite sensations, because the nerve-centres are inactive. In profound insensibility, from chloroform or ether, a limb may be removed without occasioning the least feeling. [Sidenote: 3. Sensibility in animals? In the earth-worm? In man?] 3. VARIETY OF SENSATIONS.--All animals have some degree of sensibility. It is of course feeble and indistinct in the lower forms of life, but increases in power and variety as we ascend the scale. In the earth-worm, the nervous system is very simple, the sensibility being moderate and alike in all parts: hence, if its body be cut into two pieces, each piece will have the same degree of feeling as before. As we approach man, however, the sensations multiply and become more acute; the organs are more complex, and special parts are endowed with special gifts. These special organs cannot be separated from the rest of the body without the loss of the functions they are designed to exercise. [Sidenote: 4. The lowest form of sensation? The highest? Sensations, how modified? What further can you state as to habitual impressions?] 4. The lowest form of sensation, that of simple contact, is possessed by the lowest of the animal creation. The highest forms are those by which we are enabled to know the properties of external objects, such as shape, size, sound, and color. A variety of means of communicating with the outer world is the necessary possession of a high intelligence. Sensations are modified by use. They become more acute and powerful by moderate exercise; or, they are dulled by undue excitement. The former is shown by the acute hearing of the Indian, by the sharp sight of the sailor, and by the delicate touch of the blind. The latter is exemplified by the impaired hearing of the boiler-maker, and the depraved taste of him who uses pungent condiments with his food. Again, impressions habitually presented may not be consciously felt; as is the case with the rumbling of carriages in a neighboring {179} street, or the regular ticking of a clock. All sensations become less vivid with the advance of age, especially hearing and vision. [Sidenote: 5. General sensibility? What have we seen as regards the brain? Of what other structures is the same true?] 5. GENERAL SENSIBILITY.--There is a property possessed by nearly all parts of the human body which we call general sensibility. We have recently seen that the brain is wholly insensitive, and may be cut or pinched without pain. The same is true of the nails, hair, the scarf-skin or external covering of the body, and a few other structures. In these parts no nerves are found. On the other hand, the sensibility of the true skin, and of mucous membranes, as of the eye and nose, is exquisite, these organs having a large supply of sensory nerve-fibres. The bones and tendons have less of these fibres, and are only moderately sensitive. [Sidenote: 6. The cause of sensibility? Painful part in a surgical operation? Benumbing the surface? How done by ether?] 6. The sensibility of any part of the body, then, depends upon the number of nerves present; and, as a rule, the nervous supply is proportional to the importance of the part, and to its liability to injury. When, therefore, a surgical operation is performed, the most painful part of it is the incision through the skin; the muscles, cartilage, and bone being comparatively without sensation. Hence, if we could benumb the surface, certain of the lesser operations might be undergone without great inconvenience. This is, in fact, very successfully accomplished by means of the cold produced by throwing a spray of ether, or of some other rapidly evaporating liquid, upon the part to be cut. [Sidenote: 7. Tickling? Internal sensations? The nerves of general sensibility?] 7. Tickling is a modification of general sensibility. At first, it excites a pleasurable sensation, but this soon passes into pain. It is only present in those parts where the sense of touch is feeble. But all impressions are not received from without: there are, also, certain internal {180} sensations, as they are called, which depend upon the condition of the internal organs, such as appetite, hunger, thirst, the sense of satisfaction after taking food, dizziness when looking down from some lofty position, lassitude, drowsiness, fatigue, and other feelings of comfort or discomfort. General sensibility, whether of the internal or external organs of the body, chiefly depends upon the sensory fibres of the spinal nerve. The face, however, is supplied by the sensory cranial nerves. The sympathetic system has a low grade of feeling in health; but disease in the parts served by it arouses an intense degree of pain. [Sidenote: 8. Connection between pain and sensibility?] 8. THE SENSATION OF PAIN.--What then is _pain_? Is it identical with ordinary sensibility? There seems to be some necessary connection between the two feelings, for they take place through the same channels, and they are alike intense in the same situations. But sensibility habitually contributes to our sources of pleasure, the very opposite of pain; hence, these feelings cannot be identical. [Sidenote: 9. Explain the difference between pain and sensibility.] 9. Pain must, therefore, be a modification of the general sensibility, which follows an excessive degree of excitement of the nerves; there being a natural limit to the amount of stimulation which they will sustain. So long as this limit is observed, the part excited may be said to be simply sensitive; but when it is exceeded, the impression becomes painful. This difference between sensibility and pain is well shown by the effects of sunlight upon the eye. The indirect illumination of the sun arouses only the former feeling, and is indispensable to our comfort and existence; while the direct ray received into the eye occasions great pain. [Sidenote: 10. Dread of pain? How may its value be appreciated? Example.] 10. THE USES OF PAIN.--The dread of pain is a valuable monitor to the body. It puts us on our guard in the presence of danger; teaches moderation in the use of our {181} powers; indicates the approach of disease; and calls attention to it when present. The word disease, in fact, according to its original use, had reference simply to the pain, or want of ease, which commonly attends disordered health. When we observe the serious mishaps which occur when sensibility and pain are absent, we cannot fail to appreciate its value. For example, a paralytic in taking a foot-bath, forgets to test its temperature, and putting his limbs into water while it is too hot, is severely scalded without knowing it. [Sidenote: 11. The case of the traveller? Grain of sand? The sun and child?] 11. A traveller, overcome by cold and fatigue, lies down and falls asleep near a large fire, and when he is aroused in the morning, it is discovered that one of his feet has been insensibly destroyed. A grain of sand, lodging in an insensitive eye, may cause inflammation and even the loss of sight. If intense light were not painful to the eye, many a child would innocently gaze upon the glories of the sun to the ruin of his sight. [Sidenote: 12. Mission of pain? Painful impressions compared with those of pleasure?] 12. Pain is, indeed, a present evil, but its relations with the future prove its mission merciful. Painful impressions cannot be recollected from past experience; and they cannot be called into existence by the fancy. Considered in the light of results, pain has a use above that of pleasure; for while the immoderate pursuit of the latter leads to harm, the tendency of pain is to restrict the hurtful courses of life, and in this manner to protect the body. [Sidenote: 13. What does Magendie say of the relation of pain to pleasure?] 13. The relations of pain to pleasure are thus described by the eminent physiologist, Magendie:--"By these sensations Nature induces us to concur in the order which she has established among organized beings. Though it may appear like sophistry to say that pain is the shadow of pleasure, yet it is certain that those who have exhausted the ordinary sources of pleasure have recourse to the {182} causes of pain, and gratify themselves by their effects. Do we not see in all large cities, that men who are debauched and depraved find agreeable sensations, where others experience only intolerable pain?" [Sidenote: 14. The law of Nature as regards painful sensations among animals?] 14. As to painful sensation among the inferior animals, the plan of Nature seems to be, that the higher the intelligence of the creature, and the more complete its power of defence, the more acute is its sensibility. We infer, therefore, that animals low in the scale of existence, and helpless, are not very liable to suffer pain. [Sidenote: 15. The sensation of contact and pain? Special sensations of man? How regarded?] 15. SPECIAL SENSATION.--The sensations of simple contact and pain are felt by nearly all parts of the system, whether external or internal, and are the necessary consequence of the general sensibility; but, so far as the objects which surround us are concerned, these impressions are vague and passive in character, and inform the mind of none of the properties or powers of these objects. Besides these feelings, therefore, man is endowed with certain special sensations, which are positive and distinct in character, and which he can call into exercise at will, and employ in the pursuit of knowledge. For reasons relating to the original constitution of the body, these sensations are to be regarded as modifications of the general sensibility already alluded to, constructed with special reference to the different forces of Nature, of which we have any knowledge, such as heat, motion, gravity, sunlight, and the like. [Sidenote: 16. What are the special senses? Special organs for them?] 16. These distinct and active faculties are termed the special senses, and are five in number, viz., Touch, Taste, Smell, Sight, and Hearing. For the exercise of these senses, special organs are furnished, such as the hand, the tongue, the nose, the eye, and the ear. The manner in which the nerves of special sense terminate, varies in the {183} case of each organ, so that each is adapted to one set of sensations alone, and is incapable of perceiving any other. Thus the nerve of hearing is excited by the undulations of sound, and not by those of light, while the reverse is true of the nerve of sight; and the nerve of smell can appreciate neither of them, being capable only of taking cognizance of the odorous properties of bodies. [Sidenote: 17. What is said in relation to one more than the five senses?] 17. By some writers six senses are accorded to man; the additional one being either the sense of temperature, for as we shall presently see this is not the same as touch; or according to others, the muscular sense by which we are enabled to estimate the weights of bodies. The latter also differs in some respects from the sense of touch. [Sidenote: 18. The sense of touch, how prevalent? What is said of the hand?] 18. ORGANS OF TOUCH.--The sense of touch is possessed by nearly all portions of the general surface of the body, but it finds its highest development in the hands. The human hand is properly regarded as the model organ of touch. The minute structure of the skin fits it admirably for this form of sensation: the cuticle, or scarf-skin, is fine and flexible, while the cutis, or true skin, contains multitudes of nerve-filaments, arranged in rows of _papillæ_, or cone-like projections, about one-hundredth of an inch in length. It is estimated that there are 20,000 of these papillæ in a square inch of the palmar surface of the hand. Now, although the nerves of the cutis are the instruments by which impressions are received and transmitted to the brain, yet the cuticle is essential to the sensation of touch. This is shown by the fact that whenever the true skin is laid bare, as by a burn or blister, the only feeling that it experiences from contact is one of pain, not that of touch. [Sidenote: 19. Office of the cuticle? Tips of the fingers? The fingers with thumb?] 19. The office of the cuticle is thus made evident: it is to shield the nerve filaments from direct contact with {184} external objects. At the tips of the fingers, where touch is most delicate, the skin rests upon a cushion of elastic material, and receives firmness and permanence of shape by means of the nail placed upon the less sensitive side. Besides these favorable conditions, the form of the arm is such, and its motions are so easy and varied, that we are able to apply the test of touch in a great number of directions. The slender, tapering fingers, with their pliant joints, together with the strong opposable thumb, enable the hand to mold itself upon and grasp a great variety of objects; so that great as are the delicacy and grace of the hand, it is not wanting in the elements of power. [Sidenote: 20. What special importance is attributed to the hand?] 20. Its beauty and adaptation to the wants of man have made the hand an attractive theme for philosophers. They do not, however, always agree in their conclusions. One has the opinion that man has acquired his intelligence and achieved his place as "lord of creation," because he has this organ. Buffon, in effect, declares that with fingers twice as numerous and twice as long, we would become proportionally wiser; but Galen long ago took a more reasonable view, when he taught that "man is the wisest of animals, not because he possesses the hand; but because he is the wisest and understands its use, the hand has been given to him; for his mind, not his hand has taught him the arts." Another has well said, that "no one can study carefully the human hand and fail to be convinced of the existence of the Deity." [Sidenote: 21. The simplicity of touch? What does it teach us?] 21. THE SENSE OF TOUCH.--Touch is the simplest of the senses. It is that which the child first calls into exercise in solving the early problems of existence; and it is that which is in the most constant use throughout life. We are brought by the touch into the most intimate relations with external objects, and by it we learn the greater number, if not the most important, of the properties of {185} these objects; such as size, figure, solidity, motion, and smoothness or roughness of surface. [Sidenote: 22. Importance of the sense of touch to the development of the other senses?] 22. The sense of touch assists the other senses, especially that of sight, giving foundation and reality to their perceptions. Without it, the impressions received by the eye would be as vague and unreal as the figures that float through our dreams. A boy who had been blind from birth, at the age of twelve years received sight by means of a surgical operation: at first, he was unable to distinguish between a globe and a circular card, of the same color, before he had touched them. After that, he at once recognized the difference in their form. He knew the peculiarities of a dog and a cat by feeling, but not by sight, until one day, happening to take up the cat, he recognized the connection of the two sorts of impressions, those of touch and sight; and then, putting the cat down, he said: "So, puss, I shall know you next time." [Illustration: FIG. 45.] [Sidenote: 23. Liability of touch to err? Describe the illustration.] 23. Touch is considered the least liable to error of all the senses; yet, if that part of the skin by which the sense is exercised is removed from its customary position, a false impression may be created in the mind. This is well illustrated by an experiment, which dates from the time of Aristotle. If we cross the middle finger behind the {186} forefinger, and then roll a marble, or some small object, upon the tips of the fingers (see Fig. 45), the impression will be that two marbles are felt. If the fingers, thus transposed, be applied to the end of the tongue, two tongues will be felt. When the nose is accidentally destroyed, the surgeon sometimes performs an operation for the purpose of forming a new one, by transplanting a partially removed piece of the skin of the forehead upon the injured part: then, if the new nose be touched or pinched, the feeling is referred to the forehead. This fact illustrates one important truth, that the nerves will re-unite after they have been cut, and feeling will be restored: if it were otherwise, a succession of slight cuts upon the fingers would seriously impair their tactile sensibility. [Sidenote: 24. The delicacy of touch? Experiments with a pair of compasses?] 24. THE DELICACY OF TOUCH.--Although the hand is the proper organ of this sense, yet it is exercised by various parts of the body, their degree of sensibility being proportional to the number of papillæ they contain. The varying degrees of tactile delicacy of the different parts of the surface have been measured, in an ingenious manner, by means of a pair of compasses, tipped with small pieces of cork. The two points of the compasses are touched at the same moment to the skin, the eyes being closed, and it is found that, in sensitive parts, the distance between the points may be quite slight, and yet each be plainly felt; while, in less sensitive parts, the points of the compasses are felt as a single point, although they are separated one or two inches. [Sidenote: 25. Further experiments and results?] 25. At the tips of the fingers, the distance between the points being one-twentieth of an inch, a double impression is felt. The distance must be twice as great, for the palm; four times as great, for the lips; and, on the forehead, it must be twenty times greater. At the middle of the back, where the touch is least acute, the points must be {187} separated more than two inches before they can be separately felt. Therefore, the sense of touch in the fingers is said to be fifty times more delicate than upon the posterior surface of the body. [Sidenote: 26. Exquisite delicacy of touch? The same among the blind?] 26. Exquisite delicacy of touch is attained by practice. This is shown in many of the lighter and more graceful employments of daily life. Without it, the skill of the painter, sculptor, and musician would be rude indeed. By training, also, the physician acquires the _tactus eruditus_, or discriminating touch; but among the blind, delicacy of touch is most remarkable, and it here finds its highest value; for its possession, in a measure, compensates the loss of sight by enabling them to read, by means of raised letters, to work with certain tools, and even to play upon musical instruments. A person born without sight, and without hearing or voice, may, by the education of the touch, be rescued from apparent imbecility, and be taught not only to read and write, but even to perform household and other useful labors. [Sidenote: 27. Rival candidates for the sixth sense? Give the two reasons on the subject.] 27. SENSATIONS OF TEMPERATURE AND WEIGHT.--Each of these sensations has been described by the physiologists as a special sense, and they are rival candidates, so to speak, for the position and title of the sixth sense. In the sensation of temperature, or the thermal sense, touch bears a part, but the two feelings appear to be distinct. In proof of this, we observe, firstly, that they are not alike intense in the same situations; as, for example, the skin of the face and elbow, where the sense of touch is feeble, is very sensitive to impressions of heat and cold. Secondly, the ability to recognize temperature may be lost by paralysis, while the sensibility of touch remains unaffected. When the skin comes in contact with a very hot substance, the sensation felt is that of pain, not of touch. In like manner, a {188} very cold substance causes pain, not the feeling of cold. So that a red-hot iron, and solid carbonic acid (the temperature of which is 108° below zero), feel alike; and each, if pressed slightly, will produce a blister. [Sidenote: 28. The muscular sense? State what is said to illustrate the subject.] 28. The _muscular sense_, by some considered distinct from touch, gives rise to the sensations of weight, and other forms of external resistance. That this feeling exists, is shown by the following simple experiment. If the hand be placed flat upon a table, and a somewhat heavy weight be put into it, touch alone is exercised and a feeling of pressure results; but if the hand be raised, a certain amount of muscular effort must be put forth, and thus the sensation of weight is recognized. Through the muscular sense, precision of effort is rendered possible; for by it we learn to adjust the force exerted to the weight of the object to be lifted, moved, or carried. Without it, all our movements would necessarily become ill-regulated and spasmodic. In cases of disease, where the sensibility of the lower limbs is lost, while power of motion remains, the patient is able to stand erect so long as he can see his limbs; but just as soon as his eyes are closed, he begins to waver, and will fall unless supported. [Sidenote: 29. The organ of taste? The tongue? Its powers of motion?] 29. THE ORGAN OF TASTE.--The _tongue_ is the special organ of the sense of taste; but the back part of the mouth also possesses this faculty. The tongue is a muscular organ, the muscles composing it being so numerous and interwoven as to give it the freedom and variety of motion which it possesses. It can curve itself upward or downward; it can extend or contract itself; and, with its point, can sweep the cavity of the mouth, in all directions, in the search for scattered particles of food. [Sidenote: 30. Peculiarities of the tongue? Uses of the papillæ?] 30. The upper surface of the tongue is peculiar, being marked by the presence of innumerable _papillæ_, some of {189} which are of microscopic size, resembling those that abound in the fingers, and in other parts of the body that have the sense of touch. Others are much larger, and give to the tongue its roughness of feeling and appearance. Through the medium of these papillæ, the tongue receives impressions of touch and temperature, as well as taste: indeed, its extremity is fully as delicate, in respect to tactile sensations, as the tips of the fingers themselves. It can recognize the two points of the compasses when separated not more than one-twenty-fourth of an inch; the back of it is much less sensitive to touch, while at the same time it is more highly sensitive to impressions of taste. [Sidenote: 31. Resemblance to the parts of the tongue? Powers and functions of the parts?] 31. Each lateral half of the tongue resembles the other in structure, and each receives the same number of nerves--three. One of these regulates motion, the other two are nerves of special sense. One of the latter supplies the front half of the tongue, and is called the _gustatory_ nerve. This is a branch of the great cranial nerve, called the "fifth pair," which ramifies in all parts of the face. The back of the tongue is endowed with the power of taste through a nerve known as the _glosso-pharyngeal_, because it is distributed both to the tongue and throat. This difference in the nervous supply of the tongue becomes significant, when we learn, as we shall presently, that each part of it perceives a different class of flavors. [Sidenote: 32. Taste? What are the requisites to taste?] 32. THE SENSE OF TASTE.--Taste is the special sense by means of which we discover the savors, or flavoring properties of the substances, which come in contact with the tongue. Mere contact with the surface of the tongue, however, is not sufficient, but contact with the extremities of the nerves of taste within the papillæ is required. In order that the substance to be tasted may penetrate the {190} cells covering the nerves, it must either be liquid in form, or readily soluble in the watery secretion of the mouth, the saliva. The tongue must be moist also. If the substance be insoluble, as glass or sand, or the tongue dry, the sense of taste is not awakened. In sickness, when the tongue is heavily coated, the taste is very defective, or, as is frequently expressed, "nothing tastes aright." [Sidenote: 33. Portions of the tongue endowed with taste? Where else does the sense lodge? What is stated in respect to sweet and bitter flavors? Reflex effects mentioned?] 33. All portions of the tongue are not alike endowed with the sense of taste, that function being limited to the posterior third, and to the margin and tip of this organ. The soft palate, also, possesses the sense of taste; hence, an article that has an agreeable flavor may very properly be spoken of as palatable, as is often done. All parts of the tongue do not perceive equally well the same flavors. Thus, the front extremity and margin, which is the portion supplied by the "fifth pair" of nerves, perceives more acutely sweet and sour tastes; but the base of the tongue, supplied by the _glosso-pharyngeal_ nerve, is especially sensitive to salt and bitter substances. The nerve of the front part of the tongue, as before stated, is in active sympathy with those of the face, while the relations of the other nerve are chiefly with the throat and stomach; so that when an intensely sour taste is perceived, the countenance is involuntarily distorted, and is said to wear an acid expression. On the other hand, a very bitter taste affects certain internal organs, and occasions a sensation of nausea, or sickness of the stomach. [Sidenote: 34. What is stated of the relations of taste with other senses?] 34. RELATIONS OF TASTE WITH OTHER SENSES.--Taste is not a simple sense. Certain other sensations, as those of touch, temperature, smell, and pain, are blended and confused with it; and certain so-called tastes are really sensations of another kind. Thus an astringent taste, like that of alum, is more properly an astringent feeling, and {191} results from an impression made upon the nerves of touch, that ramify in the tongue. In like manner, the qualities known as smooth, oily, watery, and mealy tastes, are dependent upon these same nerves of touch. A burning or pungent taste is a sensation of pain, having its seat in the tongue and throat. A cooling taste, like that of mint, pertains to that modification of touch called the sense of temperature. [Sidenote: 35. Its dependence on smell? on sight?] 35. Taste is largely dependent upon the sense of smell. A considerable number of substances, like vanilla, coffee, and garlic, which appear to possess a strong and distinct flavor, have in reality a powerful odor, but only a feeble taste. When the sense of smell is interfered with by holding the nose, it becomes difficult to distinguish between substances of this class. The same effect is frequently observed when smell is blunted during an ordinary cold in the head. Sight also contributes to taste. With the eyes closed, food appears comparatively insipid; and a person smoking tobacco in the dark is unable to determine by the taste whether his cigar is lighted or not. Accordingly, it is not a bad plan to close the nose and shut the eyes when about to swallow some disagreeable medicine. [Sidenote: 36. The chief use of the sense of taste? The position of its organs? The rule as regards wholesome and unwholesome food? Remarks respecting the rule?] 36. INFLUENCE OF EDUCATION ON THE TASTE.--The chief use of the sense of taste appears to be to act as a guide in the selection of proper food. Hence its organs are properly placed at the entrance of the digestive canal. As a general rule, those articles which gratify the taste are wholesome; while the opposite is true of those which impress it disagreeably. This statement is more exact in reference to the early years of life than to later years, when, by reason of mischievous habits, the sense of taste has become dulled or perverted. The desires of a child are simple; he is fully satisfied with plain and wholesome articles of diet, and must usually "learn to like" those {192} which have a strongly marked flavor. Accordingly, it is far easier at this age to encourage the preference for plain food, and thus establish healthful habits, than later in life to uproot habits of indulgence in stimulating substances, after their ill effects begin to manifest themselves. [Sidenote: 37. Diversity in tastes of men? How shown? The education of the sense of taste?] 37. The tastes of men present the most singular diversities, partly the result of necessity and partly of habit or education. The Esquimaux like the rank smell of whale oil, which is a kind of food admirably suited to the requirements of their icy climate; and travellers who go from our climate to theirs are not slow to develop a liking for the same articles that the natives themselves enjoy. The sense of taste is rendered very acute by education, as is shown in an especial manner by those who become professional "tasters" of tea and wine. [Sidenote: 38. Location of the sense of smell? The nose? "Roof of the mouth?"] 38. THE SENSE OF SMELL--THE NASAL CAVITIES.--The sense of smell is located in the delicate mucous membrane which lines the interior of the nose. That prominent feature of the face, the nose, which is merely the front boundary of the true nasal organ, is composed partly of bone and partly of cartilage. The upper part of it is united with the skull by means of a few small bones; to which circumstance is due its permanence of shape. The lower portion, or tip of the nose, contains several thin pieces of cartilage, which render it flexible and better able to resist the effects of blows and pressure. Behind the nose we find quite a spacious chamber, separated from the mouth by the hard palate, forming the "roof of the mouth," and by the soft palate (see Fig. 46); and divided into two cavities by a central partition running from before backward. [Sidenote: 39. Cavities of the nose? Obstruction of the passage of air through them?] 39. These nasal cavities, constituting the true beginning of the air-passages, extend from the nose backward to the {193} upper opening of the throat, and rise as high as the junction of the nose with the forehead. The inner wall of each cavity is straight and smooth; but from the outer wall there jut into each cavity three small scroll-like bones. The structure of these bones is very light, and hence they have been called the "spongy" bones of the nose. In this manner, while the extent of surface is greatly increased by the formation of these winding passages, the cavities are rendered extremely narrow; so much so, in fact, that a moderate swelling of the mucous membrane which lines them, as from a cold, is sufficient to obstruct the passage of air through them. [Illustration: FIG. 46.--SECTION OF THE RIGHT NASAL CAVITY.] [Sidenote: 40. The special nerve of smell? Its location?] 40. THE NERVE OF SMELL.--The internal surface of the nasal passages is covered by a delicate and sensitive mucous membrane. Its surface is quite extensive, following as it does, all the inequalities produced by the curved spongy bones of the nose. The upper portion of it alone is the seat of smell, since that part alone receives branches from the "first pair" of cranial nerves, or the olfactory nerve, which is the special nerve of smell (see Fig. 43). In Fig. 46 is shown the distribution of this nerve, in the form of an intricate network upon the two upper spongy bones. The nerve itself (1) does not issue from the skull, but rests upon a thin bone which separates it from the cavity of the nose; and the branches which proceed from it pass through this bone by means of numerous small openings. The {194} engraving represents the outer surface of the right nasal cavity; the three wave-like inequalities, upon which the nervous network is spread out, are due to the spongy bones. The left cavity is supplied in the same manner. [Sidenote: 41. Branches of the "fifth pair" of nerves? Nasal mucus? Birds?] 41. The nerves which ramify over the lower part of the membrane, and which endow it with sensibility to touch and pain, are branches of the "fifth pair" of nerves. An irritation applied to the parts where this nerve is distributed occasions sneezing, that is, a spasmodic contraction of the diaphragm; the object of which is the expulsion of the irritating cause. The manner in which the olfactory nerve-fibres terminate is peculiar. Unlike the extremities of other nerves, which are covered in by a greater or less thickness of tissue, these come directly to the surface of the mucous membrane, and thus come into very close contact with the odorous particles that are carried along by the respired air. The surface is at all times kept in a moist condition by an abundant flow of nasal mucus; otherwise it would become dry, hard, and insensitive from the continual passage of air to and fro in breathing. Birds, which respire more actively than men, have a special gland, for secreting a lubricating fluid, located in the air-passages of the head. [Sidenote: 42. Smell? Touch? Taste? Design of smell? Invisible and gaseous particles? The extreme fineness of the particles? Musk? In other cases?] 42. THE USES OF THE SENSE OF SMELL.--Smell is the special sense which enables us to appreciate odors. Touch, as we have seen, is largely concerned with solid bodies; and taste, with fluids, or with solids in solution. Smell, on the other hand, is designed to afford us information in reference to substances in a volatile or gaseous form. Invisible and subtile particles emanate from odorous bodies, and are brought by the respired air in contact with the terminal filaments of the olfactory nerve, upon which an agreeable or disagreeable impression is produced. {195} The fineness of the particles that constitute odors is often so extreme, that they elude all attempts to measure or weigh them. A piece of musk, for instance, may be kept for several years, constantly emitting perfume, without any appreciable loss of weight. In other cases, a loss of substance is perceptible, such as the essential oils, which enter into the composition of the ordinary perfumes. [Sidenote: 43. Aid given by smell? The highest use of the sense? Explain the manner.] 43. Smell, like taste, aids us in the choice of proper food, leading us to reject such articles as have a rank or putrid odor, and which are, as a rule, unfit to be eaten. The highest usefulness of this sense, however, consists in the protection it affords to the organs of respiration. Stationed at the gateways of the air-passages, it examines the current of air as it enters, and warns us of the presence of noxious gases, and of other and generally invisible enemies to health. Not all dangerous vapors are offensive, but almost all offensive vapors are unfit to be breathed. A number of small stiff hairs grow from the margin of the nostrils to prevent the entrance of dust and other atmospheric impurities, which would be alike injurious to the olfactory mucous membrane and to the lungs. The benevolent design of the Maker of our bodies may be observed in all parts of their mechanism; but, probably, in none is it more clearly displayed than in connection with the sense of smell. [Sidenote: 44. Sense of smell in the inferior animals? How, and in what cases, illustrated?] 44. The sense of smell is developed in a remarkable degree in certain of the inferior animals, and is especially acute in reference to the peculiar emanations that appear to characterize the different animals. The lion and other carnivorous beasts scent their prey from a great distance; and the fox-hound is able to track the fox through thickets and over open country for many miles; while the timid, helpless herbivora, such as the deer and sheep, find in the {196} sense of smell a means of protection against their natural enemies, of whose approach they are in this manner warned. By training this sense in the dog, and making it subservient to his use, man is able to hunt with success certain shy and very fleet animals, which otherwise he could but seldom approach. Among men, individuals differ greatly in respect to the development of this sense; and especially in certain savage tribes it is found to be extremely delicate. Humboldt states that the natives of Peru can, by this sense, distinguish in the dark between persons of different races. [Sidenote: 45. What is sight? What information does it furnish? Composite visual sensations?] 45. THE SENSE OF SIGHT.--Sight, or Vision, is the special sense by means of which we appreciate the color, form, size, distance, and other physical properties of the objects of external nature. Primarily, this sense furnishes us with information concerning the different shades of color and the different degrees of brightness: these are the simple sensations of sight, such as the yellowness and glitter of a gold coin. In addition to these, there are composite visual sensations, produced by the joint action of the other senses and by the use of the memory and judgment; such as, in the case of the coin, its roundness, solidity, size, its distance and direction from us. So that many of our sensations, commonly considered as due to sight, are in reality the results of intellectual processes which take place instantaneously and unconsciously. [Sidenote: 46. Comparison between sight and hearing? Relative capacity of deaf and blind?] 46. This faculty not only has value in the practical every-day affairs of life, but it contributes so largely to the culture of the intellect and to our higher forms of pleasure, that some writers are disposed to rate it as the first and most valuable of the senses. Others, however, maintain that the sense of hearing does not yield in importance to that of sight; and they cite in support of their position {197} the fact that the blind are commonly cheerful and gay, while the deaf are inclined to be morose and melancholy. In respect to the relative capacity for receiving education in the deaf and blind, it is found that the former learn more quickly, but their attainments are not profound; while the blind acquire more slowly, but are able to study more thoroughly. [Sidenote: 47. Sight, unlike the other senses? In the case of the stars?] 47. LIGHT.--THE OPTIC NERVE.--Unlike the senses previously considered--touch, taste, and smell--sight does not bring us into immediate contact with the bodies that are examined; but, by it, we perceive the existence and qualities of objects that are at a greater or less distance from us. In the case of the stars, the distance is incalculable, while the book we read is removed but a few inches. Light is the agent which gives to this sense its wide range. The nature of this mysterious force is not known, and it is not here to be discussed; since its study belongs more properly to the province of natural philosophy. [Sidenote: 48. The undulatory theory of light? What does the theory suppose?] 48. It is sufficient, in this connection, to state that the theory of light now generally accepted, and which best explains the facts of optics, is that known as the undulatory theory. This theory supposes that there exists an intangible, elastic medium, which fills all space, and penetrates all transparent substances, and which is thrown into exceedingly rapid undulations or waves, by the sun and every other luminous body; the undulations being propagated with extreme rapidity, and moving not less than 186,000 miles in a second. [Sidenote: 49. The sensation of light? Optic nerve?] 49. These waves are thought to produce in the eye the sensation of light, in the same manner as the sonorous vibrations of the air produce in the ear the sensation of sound. That part of the eye which is sensitive to these waves is the expansion of the _optic nerve_. It is sensitive {198} to no other impression than that of light, and it is the only nerve which is acted upon by this agent. The optic nerve, also called the "second pair" of cranial nerves, is the means of communication between the eye and the brain. [Sidenote: 50. The two nerves constituting the pair of nerves?] 50. The two nerves constituting the pair, arise from ganglia lying at the base of the cerebrum, one of them on each side; from which points they advance to the eyes, being united together in the middle of their course in the form of the letter X (Fig. 43--2). By this union the two eyes are enabled to act harmoniously, and in some respects to serve as a double organ. And by reason of this same intimate nervous communication, when serious disease affects one eye, the fellow-eye is extremely liable to become the seat of _sympathetic_ inflammation; and this, if neglected, almost certainly results in hopeless blindness. [Sidenote: 51. Why is the eye called the "window of the soul?" Why, the subject of enthusiastic study?] 51. THE ORGAN OF SIGHT.--THE EYE.--The proximity of the eye to the brain, and the important part it performs in giving expression to the emotions, have given it the name of "the window of the soul." The exceeding beauty of its external parts, and the high value of its function, have long made this organ the subject of enthusiastic study. It is chiefly within the last twenty years, however, that this study has been successful and fruitful of practical results. Several ingenious instruments have been invented for the examination of the eye in health and disease, and new operations have been devised for the relief of blindness and of impaired vision. As a result, it is now a well-marked fact that, in civilized lands, the number of those who suffer from loss of sight is proportionally much less than in countries where science is less known and cultivated. [Sidenote: 52. The most obvious fact? The consequence? The next thing noticed? Its range of view? Of what does the organ of vision consist?] 52. The most obvious fact in respect to the apparatus of {199} sight is that there are two eyes, which may either act together as one, and be fixed upon one object, or one eye may be used independently of the other. In consequence of this arrangement the loss of one eye does not necessitate blindness, and, in fact, it not infrequently happens that the sight of one eye may be long impaired or lost before the fact is discovered. We next notice that it is placed at the most elevated part of the body, in front, and near the brain. It also commands a wide range of view, being itself moved with great rapidity, and being further aided by the free motion of the head and neck. The organ of vision consists essentially of two parts: the optical instrument itself--the eyeball--and its enveloping parts, or the case in which the instrument is kept free from harm. The latter, which are external, and which we shall first consider, are chiefly the _Orbits_, the _Eyelids_, and the apparatus for the _Tears_. [Sidenote: 53. The protection of the eyeball against injury? The overhanging brow? The opening for the optic nerve?] 53. THE ORBITS.--The eyeball, which is a delicate organ, is well defended against external injury within the orbits or bony sockets of the head. These are deep conical hollows, bounded in part by the bones of the skull, and in part by those of the nose and cheek. The orbit juts out beyond the most exposed portion of the eyeball, as may be seen by laying a book over the eye, when it will be found that no part of the eyeball, unless it be very prominent, will be touched by the book; so that the only direction in which an injury is liable to be received is immediately in front of the eye. The overhanging brow is itself covered by a layer of thick skin, studded with short, stout hairs, which are so bent as to prevent the perspiration from running into the eye and obscuring vision. Through a hole in the bottom of the orbit, the nerve of sight passes outward from the brain. The orbit also contains a considerable amount of a fatty tissue, upon which, as upon an elastic cushion, the eye rests. {200} [Illustration: FIG. 47.--FRONT VIEW OF RIGHT EYE. (Natural Size.) 1. The Lachrymal, or tear gland, lying beneath the upper eyelid. 2. The Nasal Duct is shown by the dotted line. The * marks the orifice in the lower lid. The central black spot is the _pupil_; surrounding it is the _iris_; and the triangular white spaces are the visible portion of the _sclerotic_.] [Sidenote: 54. What are the eyelids? The upper lid? The lower one? The mucous membrane of the eye?] 54. THE EYELIDS.--The eyelids are two movable curtains, or folds, which, when shut, cover the front part of the orbit, and hide the eye from view. The upper lid is the larger, has a curved margin, and moves freely, while the lower lid is comparatively short and straight, and has but a slight degree of motion (Fig. 47). Skin covers the exterior of the lids, while a fine mucous membrane lines their inner surface, and is likewise spread out over the entire front of the eyeball. This membrane, which is called the _Conjunctiva_, is highly sensitive, and thus plays an important part in protecting the eye against the lodgment of sand, ashes, chaff, and other foreign particles that are blown about in the air. This sensitive membrane will not endure the presence of these particles. If any find access, it causes a constant winking, a flow of tears, and other signs of irritation, until it is removed. [Sidenote: 55. The eyelashes? The little points within the line of the lashes? Of what use are these glands?] 55. The long, silky eyelashes, which garnish the edges of the lids, act like a sieve to prevent the entry of dust and the like; and together with the lids, they regulate the amount of light which is permitted to enter the eye, so that it is shielded from a sudden flood or glare of light. The little points seen in the figure just within the line of the lashes, especially on the lower lid, represent the mouths of numerous little sebaceous glands (Fig. 48, D,D), such as are always {201} found in the neighborhood of hairs. These glands supply a thick, oily material which greases the edges of the lids and prevents their adhering together, and likewise prevents the overflow of the tears upon the cheek. [Sidenote: 56. The location of the lachrymal gland? The use of the gland?] 56. THE LACHRYMAL FLUID, OR THE TEARS.--Just within the outer part of the bony arch of the brow, where the bone may be felt to be sharper than in other positions, is lodged a little organ called the lachrymal gland, the situation of which is indicated in Fig. 47, 1. This is the gland whence flows the watery secretion, commonly called the _tears_, which is designed to perform an exceedingly important duty in lubricating the lids, and in keeping the exposed surface of the eyeball moist and transparent. For, without this or some similar liquid, the front of the eye would speedily become dry and lustreless, like that of a fish which has been removed from the water: the simple exposure of the eye to the air would then suffice to destroy vision. [Sidenote: 57. When does the secretion of the tears occur? The secretion not used for the eye? Location of the nasal duct? Its use? The overflow of tears in old people?] 57. This secretion of the tears takes place at all times, during the night as well as the day; but it is seldom noticed, except when under the influence of some strong mental emotion, whether of sorrow or happiness, it is poured forth in excess, so as to overflow the lids. Strong light or a rapid breeze will, among many other causes, excite the flow of the tears. That portion of this secretion which is not used in moistening the eye is carried off into the nose by a canal situated near the inner angle of the eye, called the _nasal duct_. This duct is shown in Fig. 47, 2, and is connected with each lid by delicate tubes, which are indicated by dotted lines in the figure; the asterisk marks the little opening in the lower lid, by which the tears enter the nasal duct. By gently turning the inner part of that lid downward, and looking in a mirror, {202} this small "lachrymal point" may be seen in your own eye. In old people, these points become everted, and do not conduct the tears to the nasal cavity, so that they are inconvenienced by an overflow of tears upon the face. [Illustration: FIG. 48.--VERTICAL SECTION OF THE EYE. (Enlarged.) C, The Cornea. A, The Aqueous Humor. I, The Iris. P, The Pupil. L, The Crystalline Lens. H, The Ligament of the Lens. B, The Ciliary Process. V, The Cavity containing the Vitreous Humor. S, The Sclerotic. Ch, The Choroid. R, The Retina. N, The Optic Nerve. DD, The Eyelids. X, The Levator Muscle of the Upper Lid. Y, The Upper Straight Muscle of the Eye. Z, The Lower Straight Muscle.] [Sidenote: 58. The watery fluid passing over the eyeball? Design of the arrangement? Winking?] 58. Thus we observe that the gland which forms the tears is placed at the outer part of the eye, while their means of exit is at the inner angle of the eye; which fact renders it necessary that this watery fluid shall pass over the surface of the eyeball before it can escape. This arrangement cannot be accidental, but evinces design, for it thus secures the perfect lubrication of the surface of the eye, and cleanses it from the smaller particles of dust {203} which may enter it, in spite of the vigilance of the lids and lashes. The act of winking, which is generally unconsciously performed, and which takes place six or more times in a minute, assists this passage of the tears across the eye, and is especially frequent when the secretion is most abundant. [Sidenote: 59. Describe the shape of the eyeball. Its structure.] 59. THE EYEBALL.--The remarkable optical instrument called the eyeball, or the globe of the eye, upon which sight depends, is, as the name indicates, spherical in shape. It is not a perfect sphere, since the front part projects somewhat beyond the rest, and at the posterior part the optic nerve (Fig. 48, N) is united to it, resembling the junction of the stem with a fruit. In its long diameter, that is, the horizontal or from side to side, it measures a little more than an inch; in other directions it is rather less than an inch. In structure, the ball of the eye is firm, and its tense round contour may in part be felt by pressing the fingers over the closed lids. [Sidenote: 60. Of what is the eyeball composed? State how.] 60. The eyeball is composed chiefly of three internal, transparent media, called _humors_; and three investing coats, or _tunics_. The former are the _aqueous humor_, Fig. 48, A, the _crystalline lens_ L, and the _vitreous humor_ V. Of these the lens alone is solid. The three coats of the eyeball are called the _sclerotic_ S, the _choroid_ CH, and the _retina_ R. This arrangement exists in respect to five-sixths of the globe of the eye, but in the anterior one-sixth, these coats are replaced by the _cornea_ C, which is thin and transparent, so that the rays of light pass freely through it, as through a clear window-pane. [Sidenote: 61. The shape of the cornea? Its structure? The "white of the eye?"] 61. In shape, the cornea is circular and prominent, resembling a miniature watch-glass, about 1/25 of an inch thick. In structure, it resembles horn (as the name signifies), or the nail of the finger, and is destitute of {204} blood-vessels. The _Sclerotic_ (from _scleros_, hard) is composed of dense, white fibrous tissue, and gives to the eyeball its firmness of figure and its white color; in front, it constitutes the part commonly called "the white of the eye." It is one of the strongest tissues in the body; it possesses very few vessels, and is not very sensitive. It affords protection to the extremely delicate interior parts of the eye; and the little muscles which effect its movements are inserted into the sclerotic a short distance behind the cornea (see Fig. 48, Y, Z). It is perforated posteriorly to admit the optic nerve. [Sidenote: 62. The second or middle coat of the eyeball? Its dark color?] 62. The _Choroid_ is the second or middle coat of the eyeball, and lies closely attached to the inner surface of the sclerotic. Unlike the latter tunic, its structure is soft and tender, it is dark in color, and possesses a great abundance of blood-vessels. Its dark color is due to a layer of dark brown or chocolate-colored cells spread out over its inner surface. This dark layer serves to absorb the rays of light after they have traversed the transparent structures in front of it; if the rays were reflected from side to side within the eye, instead of being thus absorbed, confused vision would result from the multitude of images which would be impressed upon the optic nerve. [Sidenote: 63. Similar mechanism in microscopes? The albinos? White rabbits?] 63. This mechanism has been unconsciously imitated by the opticians, who, when they make a microscope or telescope, take care that the interior of its tube shall be coated with a thick layer of black paint or lamp-black; for without it, a clear delineation of the object to be viewed is impossible. The albinos, in whom these dark cells of the choroid are wanting, have imperfect vision, especially in the daytime and in strong lights. The dark cells are also wanting in white rabbits, and other animals that have red or pink eyes; their vision appears to be imperfect in the presence of a bright light. {205} [Sidenote: 64. What is the iris? Its construction? How is the size of the pupil regulated?] 64. THE IRIS.--Continuous with the choroid, in the front part of the globe of the eye, is a thin, circular curtain, which occasions the brown, blue, or gray color of the eye in different individuals. On account of the varieties of its color, this membrane has received the name _Iris_, which is the Greek word for "rainbow" (see Fig. 48, I). A front view of it is shown in Fig. 47. The iris is pierced in its centre by a round opening, called the _pupil_ (P), which is constantly varying in size. In olden times it was spoken of as the "apple of the eye." The hinder surface of the iris, except in albinos, has a layer of dark coloring matter resembling that of the choroid. The iris is a muscular organ, and contains two distinct sets of fibres; one of which is circular, while the other radiates outward from the pupil. The action of these sets of fibres regulates the size of the pupil; for when the circular set acts, the pupil contracts, and when the other set acts, the opening expands. Their action is involuntary, and depends on the reflex system of nerves, which causes the contraction of the pupil when a strong light falls upon the eye, and its expansion when the illumination is feeble. [Sidenote: 65. The admission of light to the eye? The action of the iris under different circumstances? The lustre of the eye, how affected in youth and old age?] 65. The iris, accordingly, serves a very useful purpose in regulating the admission of light to the eye. It, however, does not act instantaneously; and hence, when we pass quickly from a dark room into the bright sunlight, the vision is at first confused by the glare of light, but as soon as the pupil contracts, the ability to see becomes perfect. On the other hand, when we enter a dark apartment, such as a cellar, for a short time we can see nothing clearly; but as soon as the pupil expands and admits more light, we are enabled to distinguish the surrounding objects. Animals of the cat species, and others which prowl around after nightfall, are enabled to see in the dark by {206} having the iris very dilatable. The size of the pupil affects the lustre of the eye. When it is large, as it usually is during youth, the eye appears clear and brilliant; while in old age the pupil is small and the eye is dull. The brilliancy of the eye is in part, at least, dependent upon the reflection of light from the front surface of the crystalline lens. [Sidenote: 66. Means used to increase the beauty of the eye? The injurious consequences?] 66. Certain poisonous vegetables have the property of causing the pupil to dilate, and have been used in small doses to increase the beauty of the eye. One of these drugs has been so largely used by the ladies for this purpose, that it has received the name _belladonna_, from the Italian words meaning "beautiful lady." This hazardous practice has resulted more than once in the death of the person desiring thus to increase her personal attraction. The common English name for belladonna is "deadly nightshade." (In the diagram on page 214 the shape and relations of the iris are more accurately shown than in the figure referred to above.) [Sidenote: 67. What part does the retina constitute? How formed? Its texture? Color? Sensitiveness?] 67. THE RETINA constitutes the third and inner coat of the globe of the eye. This, the important part of the eye that is sensitive to light, is a kind of nervous membrane, formed by the expansion of the ultimate filaments of the optic nerve. Its texture is soft, smooth, and very thin; it is translucent and of an opaline, or grayish-white color. It is sensitive to light alone; and if any form of mechanical irritation be applied to it, the sensations of touch and pain are not experienced, but flashes of fire, sparks, and other luminous appearances are perceived. Thus an electric shock given to the eye-ball occasions a flash of light; and a sudden fall, or a blow upon the eye, is often apparently accompanied by the vision of "stars." [Sidenote: 68. Specific energy of the optic nerve? Trial in Germany?] 68. These phenomena are due to what is termed the {207} "specific energy" of the optic nerve, which nerve, in common with the other nerves of special sense, obeys a general law of nature, which requires that, whenever one of these nerves is stimulated, it shall respond with the sensation peculiar to itself. These flashes of retinal light have no power to illuminate external objects, although the opposite of this statement has been maintained. On the occasion of a remarkable trial in Germany, it was claimed by a person who had been severely assaulted on a very dark night, that the flashes of light caused by repeated blows upon the head enabled him to see with sufficient distinctness to recognize his assailant. But the evidence of scientific men entirely refuted this claim, by pronouncing that the eye, under the circumstances named, was incapacitated for vision. Too intense light occasions a feeling of pain, but it is of a peculiar kind, and is termed "dazzling." [Illustration: FIG. 49.] [Sidenote: 69. Sensitiveness of all parts of the retina? Experiment to prove the existence of the "blind spot."] 69. All parts of the retina are not equally sensitive, and singularly enough, the point of entry of the nerve of sight, in the back part of the eyeball, is entirely insensible to light, and is called the "blind spot." The existence of this point may be proven by a simple experiment. Hold the accompanying figure, on page 207, directly in front of and parallel with the eyes. Close the left eye, and fix the sight steadily on the left-hand circle; then, by gradually varying the distance of the figure from the eye, at a certain distance (about six inches), the right-hand circle will disappear, {208} but nearer or further than that, it will be plainly seen. The other eye may be also tried, with a similar result: if the gaze be directed to the right-hand circle, the left one will seem to disappear. The experiment may be repeated by using two black buttons on the marble top of a bureau, or on some other white surface. The blind spot does not practically interfere with vision, since the eye is seldom fixed immovably on an object, and the insensitive parts of the two eyes can never be directed upon the same object at the same time. [Sidenote: 70. Duration of impressions upon the retina? How illustrated?] 70. Impressions made upon the retina are not at once lost, but persist a measurable length of time, and then gradually fade away. Thus, a bright light or color, gazed at intently, cannot be immediately dismissed from sight by closing or turning away the eyes. A stick lighted at one end, if whirled around rapidly in the dark, presents the appearance of an unbroken luminous ring; and the spokes of a rapidly revolving carriage-wheel seem to be merged into a plane surface. If an object move too rapidly to produce this sort of lasting impression, it is invisible, as in the case of a cannon-ball passing through the air in front of us. [Sidenote: 71. What further illustration? Winking, why it is not noticed. Ease with which the retina is fatigued or deprived of sensibility? How shown?] 71. If a card, painted with two primary colors--as red and yellow--be made to rotate swiftly, the eye perceives neither of them distinctly; but the card appears painted with their secondary color--orange. The average duration of retinal images is estimated at one-eighth of a second; and it is because they thus endure, that the act of winking, which takes place so frequently, but so quickly, is not noticed and does not interrupt the vision. The retina is easily fatigued or deprived of its sensibility. After looking steadfastly at a bright light, or at a white object on a black ground, a dark spot, corresponding in shape to the bright object, {209} presents itself in whatever direction we look. This spot passes away as the retina resumes its activity. [Sidenote: 72. How further shown? How is the result accounted for? "Color-blindness?"] 72. If a bright color be gazed at intently, and the eyes then be turned to a white surface, a spot will appear; but its color will be the complement of that of the object. Fix the eye upon a red wafer upon a white ground, and on removing the wafer a greenish spot of the same shape takes its place. This result happens because a certain portion of the retina has exhausted its power to perceive the red ray, and perceives only its complementary ray, which is green. The color thus substituted by the exhausted retina is called a physiological or accidental color. In some persons the retina is incapable of distinguishing different colors, when they are said to be affected with "color-blindness." Thus, red and green may appear alike, and then a cherry-tree, full of ripe fruit, will seem of the same color in every part. Railroad accidents have occurred because the engineer of the train, who was color-blind, has mistaken the color of a signal. [Sidenote: 73. The location of the crystalline lens? How supported? Its color and texture? Shape? Size?] 73. THE CRYSTALLINE LENS.--Across the front of the eye, just behind the iris, is situated the _Crystalline lens_, enclosed within its own capsule. It is supported in its place partly by a delicate circular ligament, and partly by the pressure of adjacent structures. It is colorless and perfectly transparent, and has a firm but elastic texture. In shape it is doubly convex, and may be rudely compared to a small lemon-drop. The front face of the lens is flatter than the other, and is in contact with the iris near its pupillary margin, as is represented in the diagram on page 214. It is only one-fourth of an inch thick. [Sidenote: 74. Cataract? Aqueous humor? Vitreous humor?] 74. When this little body becomes opaque, and no longer affords free passage to the rays of light, as often happens {210} with the advance of age, an affection termed "cataract" is produced. Between the crystalline lens and the cornea is a small space which contains the _aqueous humor_ (see Fig. 48, A). This humor consists of five or six drops of a clear, colorless liquid very much like water, as its name implies. That part of the globe of the eye lying behind the lens is occupied by the _vitreous humor_, so called from its fancied resemblance to melted glass (Fig. 48, V). This humor is a transparent, jelly-like mass, enclosed within an exceedingly thin membrane. It lies very closely applied to the retina, or nervous membrane of the eye, and constitutes fully two-thirds of the bulk of the eyeball. [Illustration: FIG. 50.--THE RETINAL IMAGE.] [Sidenote: 75. What is a lens and its focus? The miniature image, how produced?] 75. THE USES OF THE CRYSTALLINE LENS.--A convex lens has the property of converging the rays of light which pass through it; and the point at which it causes them to meet is termed its focus. If a lens of this description, such as a magnifying or burning-glass, be held in front of an open window, in such a position as to allow its focus to fall upon a piece of paper, it will be found to depict upon the paper a miniature image of the scene outside of the window. It will be further noticed that the image is inverted, or upside down, and that the paper {211} at the place upon which the image is thrown is much brighter than any other part. [Sidenote: 76. How are figures painted upon the retina? How proved?] 76. Now all the transparent structures of the eye, but especially the crystalline lens, operate upon its posterior part, or retina, as the convex lens acts upon the paper; that is, they paint upon the retina a bright inverted miniature of the objects that appear in front of the eye (Fig. 50). That this actually takes place may be proved by experiment. If the eyeball of a white rabbit, the walls of which are transparent, be examined while a lighted candle is held before the cornea, an image of the candle-flame may be seen upon the retina. [Sidenote: 77. What can be said in respect to the form and structure of the crystalline lens?] 77. The form and structure of the crystalline lens endow it with a remarkable degree of refractive power, and enable it to converge all the rays of light that enter it through the pupil, to a focus exactly at the surface of the retina. When this lens is removed from the eye, as is frequently done for the cure of cataract, it is found that the rays of light then have their focus three-eighths of an inch behind the retina; that the image is four times larger than in the healthy eye, that it is less brilliant, and that its outline is very indistinct. From this we learn that one of the uses of the crystalline lens is to make the retinal image bright and sharply-defined, at the same time that it reduces its size. Indeed, the small size of the image is a great advantage, as it enables the limited surface of the retina to receive, at a glance, impressions from a considerable field of vision. [Sidenote: 78. How is the inverted image upon the retina presented in its true position to the mind?] 78. As the image upon the retina is inverted, how does the mind perceive the object in its true, erect position? Many explanations have been advanced, but the simplest and most satisfactory appears to be found in the fact that {212} the retina observes no difference, so to speak, between the right and left or the upper and lower positions of objects. In fact, the mind is never conscious of the formation of a retinal image, and until instructed, has no knowledge that it exists. Consequently, our knowledge of the relative location of external objects must be obtained from some other source than the retina. The probable source of this knowledge is the habitual comparison of those objects with the position of our own bodies: thus, to see an elevated object, we know we must raise the head and eyes; and to see one at our right hand, we must turn the head and eyes to the right. [Illustration: FIG. 51.--THE DIFFERENT SHAPES OF THE GLOBE OF THE EYE. N, The Natural Eye. M, The Short-sighted Eye. H, The Long-sighted Eye. S, Parallel Rays from the Sun.] [Sidenote: 79. The uniform perfection of the eye? Examples? The most common imperfection?] 79. LONG-SIGHT OR HYPEROPIA, AND SHORT-SIGHT OR MYOPIA.--The eye is not in all cases perfectly formed. For example, persons may from birth have the cornea too prominent or too flat, or the lens may be too thick or too thin. In either of these conditions sight will be more or less defective from the first, and the defect will not tend to disappear as life advances. The most common imperfection, however, is in the shape of the globe; which may be short (Fig. 51, H), as compared with the natural eye, N, or it may be too long, M. [Sidenote: 80. How is "long-sight" explained? "Short-sight?"] 80. When the globe is short, objects can only be clearly {213} seen that are at a distance, and the condition of the vision is known as "long-sight," or hyperopia. It will be observed, by reference to Fig. 51, that the focus of the rays of light would fall behind the retina of this eye. When the globe is too long, objects can only be clearly seen that are very near to the eye; and the condition resulting from this defect is termed "short-sight," or myopia. The focus of the rays of light is, in this case, formed in the interior of the eye in front of the retina. [Sidenote: 81. Long-sight, how common? With what must it not be confounded? Kind of glasses for short-sight? Why? Squint?] 81. Long-sight, or hyperopia, is common among schoolchildren, nearly as much so as short-sight, and must not be confounded with the defect known as the "far sight" of old people; although in both affections the sight is improved by the use of convex glasses. Children not infrequently discover that they see much better when they chance to put on the spectacles of old persons. For the relief of short-sight, concave glasses should be employed; as they so scatter the rays of light as to bring the focus to the retina, and thus cause the vision of remote objects to become at once distinct. That form of "squint," in which the eyes are turned inward, is generally dependent upon long-sight, while that rarer form, when they turn outward, is due to short-sight. [Sidenote: 82. What is stated in connection with the opera-glass? Experiment with pencil and distant object?] 82. THE FUNCTION OF ACCOMMODATION.--If, after looking through an opera-glass at a very distant object, it is desired to view another nearer at hand, it will be found impossible to obtain a clear vision of the second object unless the adjustment of the instrument is altered; which is effected by means of the screw. If an object, like the end of a pencil, be held near the eye, in a line with another object at the other side of the room, or out of the window, and the eye be fixed first upon one and then upon the other, it will be found that when the pencil is clearly seen, the {214} further object is indistinct; and when the latter is seen clearly, the pencil appears indistinct; and that it is impossible to see both clearly at the same time. Accordingly, the eye must have the capacity of adjusting itself to distances, which is in some manner comparable to the action of the screw of the opera-glass. [Illustration: FIG. 52.--THE FUNCTION OF ACCOMMODATION. The right half of the diagram shows the eye at rest. The left half shows the lens accommodated for near vision.] [Sidenote: 83. Function of accommodation? In what does it consist? How is the function explained?] 83. This, which has been called the function of accommodation, is one of the most admirable of all the powers of the eye, and is exercised by the crystalline lens. It consists essentially in a change in the curvature of the front surface of the lens, partly through its own elasticity, and partly through the action of the ciliary muscle. When the eye is at rest, that is, when accommodated for a distant object, the lens is flatter and its curvature diminished (see Fig. 52); but when strongly accommodated for near vision the lens becomes thicker, its curvature increases, and the image on the retina is made more sharp and distinct. Since a strong light is not required in viewing near objects, the pupil contracts, as is shown in the left-hand half of the diagram. {215} [Sidenote: 84. Change of sight with the approach of old age? Explain the change?] 84. OLD-SIGHT, OR PRESBYOPIA.--But this marvellously beautiful mechanism becomes worn with use; or, more strictly speaking, the lens, like other structures of the body, becomes harder with the approach of old age. The material composing the lens becomes less elastic, the power to increase its curvature is gradually lost, and as a consequence, the person is obliged to hold the book further away when reading, and to seek a stronger light. In a word, the function of accommodation begins to fail, and is about the first evidence that marks the decline of life. By looking at the last preceding diagram, and remembering that the increased curvature of the lens cannot take place, it will be at once understood why old-sight is benefitted in near vision by the convex lens, such as the spectacles of old people contain. It acts as a substitute for the deficiency of the crystalline lens. [Sidenote: 85. Hearing or audition? What is sound? How propagated commonly? Stone thrown in water?] 85. THE SENSE OF HEARING.--SOUND.--Hearing, or audition, is the special sense by means of which we are made acquainted with _sound_. What is sound? It is an impression made upon the organs of hearing, by the vibrations of elastic bodies. This impression is commonly propagated by means of the air, which is thrown into delicate undulations, in all directions from the vibrating substance. When a stone is thrown into smooth water, a wave of circular form is set in motion, from the point where the stone struck, which constantly increases in size and diminishes in force, as it advances. [Sidenote: 86. Sound-wave in the atmosphere? Its shape? Rate of motion? Sound, in water, air, and solid bodies?] 86. Somewhat resembling this, is the undulation, or sound-wave, which is imparted by a sonorous vibration to the surrounding atmosphere. Its shape, however, is spherical, rather than circular, since it radiates upward, downward, and obliquely as well as horizontally, like the wave {216} in water. The rate of motion of this spherical wave of air is about 1050 feet per second, or one mile in five seconds. In water, sound travels four times as fast as in air, and still more rapidly through solid bodies; along an iron rod, its velocity is equal to two miles per second. [Sidenote: 87. The earth as a conductor of sound? To what has the western Indian been taught? Solid substances as conductors? As regards sound, in what respect is air necessary? Sound in a vacuum?] 87. The earth, likewise, is a good conductor of sound. It is said that the Indian of our western prairies can, by listening at the surface of the ground, hear the advance of a troop of cavalry, while they are still out of sight, and can even discriminate between their tread and that of a herd of buffaloes. Solid substances also convey sounds with greater power than air. If the ear be pressed against one end of a long beam, the scratching of a pin at the other extremity may be distinctly heard, which will not be at all audible when the ear is removed from the beam. Although air is not the best medium for conveying sound, it is necessary for its production. Sound cannot be produced in a vacuum, as is shown by ringing a bell in the exhausted receiver of an air-pump, for it is then entirely inaudible. But let the air be readmitted gradually, then the tones become more and more distinct, and when the receiver is again full of air, they will be as clear as usual. 88. All sonorous bodies do not vibrate with the same degree of rapidity, and upon this fact depends the _pitch_ of the sounds that they respectively produce. The more frequent the number of vibrations within a given time, the higher will be the pitch; and the fewer their number, the lower or graver will it be. Now, the rate of the successive vibrations of different notes has been measured, and it has thus been found that if they are less than sixteen in a second, no sound is audible; while if they exceed 60,000 per second the sound is very faint, and is painful to the {217} ear. The extreme limit of the capacity of the human ear may be considered as included between these points; but the sounds which we ordinarily hear are embraced between 100 and 3,000 vibrations per second. 89. The _ear_, which is the proper organ of hearing, is the most complicated of all the structures that are employed in the reception of external impressions. The parts of which it is composed are numerous, and some of them are extremely small and delicate. Nearly all these parts are located in an irregularly shaped cavity hollowed out in the temporal, or "temple," bone of each side of the head. That part of the bone in which the auditory cavity is placed has the densest structure of all bones of the body, and has therefore been called the "petrous," or rocky part of the temporal bone. In studying the ear, it is necessary to consider it as divided into three portions, which are called, from their relative positions, the _external_ ear, the _middle_ ear, and the _internal_ ear. (In the diagram, Fig. 53, A, the first is not shaded, the second is lightly shaded, and the last has a dark background.) [Sidenote: 90. Of what does the external portion of the organ of hearing consist? Describe the portal of that organ known as the ear. Its use?] 90. THE EXTERNAL EAR.--The external portion of the organ of hearing, designated in Fig. 53, A, includes, first, that outer part (_a_), which is commonly spoken of as "the ear," but which in fact is only the portal of that organ; and, secondly, the _auditory canal_ (_b_). The former consists of a flat flexible piece of cartilage, projecting slightly from the side of the head, attached to it by ligaments, and supplied with a few weak muscles. Its surface is uneven, and curiously curved, and from its resemblance to a shell, it has been called the _concha_. It probably serves to collect sounds, and to give them an inward direction; although its removal is said not to impair the acuteness of hearing more than a few days. {218} [Sidenote: 91. The ear in the animals of delicate hearing? Rabbit? Fishes?] 91. In those animals whose hearing is more delicate than that of man, the corresponding organ is of greater importance, it being larger and supplied with muscles of greater power, so that it serves as a natural kind of ear-trumpet, which is easily movable in the direction of any sound that attracts the attention of the animal. Bold, predaceous animals generally have the concavity of this organ directed forward, while in timorous animals, like the rabbit, it is directed backward. Fishes have no outer ear, but sounds are transmitted directly through the solid bones of the head, to the internal organ of hearing. [Illustration: FIG. 53.--THE EAR AND ITS DIFFERENT PARTS. A, Diagram of the Ear. _a_, _b_, External Ear. _c_, Membrane tympani. _d_, Middle Ear. _e_, Internal Ear. B to B''', Bones of the Middle Ear (magnified). C, The Labyrinths, or Internal Ear (highly magnified).] [Sidenote: 92. What is the auditory canal? Describe it.] 92. The _auditory canal_ (Fig. 53, A, _b_), which is continuous with the outer opening of the ear, is a blind passage, an inch and a quarter in length, its inner extremity being bounded by a closely-fitting, circular membrane. This canal is of oval form, is directed forward and inward, {219} and is slightly curved; so that the inner end is ordinarily concealed from view. The pouch of the skin which lines this passage is smooth and thin, especially at the lower end, where it covers the membrane just mentioned. [Sidenote: 93. How is it guarded and protected? Ear-wax?] 93. As in the case of the nostrils, a number of small, stiff hairs garnish the margin of the auditory canal, and guard it, to some extent, against the entrance of insects and other foreign objects. The skin, too, covering its outer half, is furnished with a belt of little glands which secrete a yellow, viscid, and bitter substance, called "ear-wax," which is especially obnoxious to small insects. As the outer layer of this wax-like material loses its useful properties, it becomes dry, and falls out of the ear in the form of minute, thin scales, a fresh supply being furnished from the little glands beneath. In its form, the auditory canal resembles the tube of an ear-trumpet, and serves to convey the waves of sound to the middle portion of the ear. [Sidenote: 94. What is the middle ear? Why called tympanum?] 94. THE MIDDLE EAR, OR TYMPANUM.--The middle ear is a small cavity, or chamber, of irregular shape, about one-fourth of an inch across from side to side, and half an inch long (see Fig. 53, A, _d_). From the peculiar arrangement of its various parts it has very properly been called the _tympanum_, or the "drum of the ear." The middle ear, like the external canal, contains air. [Sidenote: 95. What is the membrana tympani? Describe it.] 95. The circular membrane, already mentioned as closing the auditory canal, is the partition which separates the middle from the external ear, and is called the _membrana tympani_ (_c_), and may be considered as the outer head of the drum of the ear. It is sometimes itself spoken of as the "drum," but this is incorrect; since a drum is not a membrane, but is the hollow space across which the membrane is stretched. This membranous drum-head is very tense and elastic, and so thin as to be almost transparent; {220} its margin is fastened into a circular groove in the adjacent bone. Each wave of sound that impinges against this delicate membrane causes it to vibrate, and it, in turn, excites movements in the parts beyond. [Sidenote: 96. What are the ossicles? Their number and names? Their arrangement?] 96. Within the tympanum is arranged a chain of remarkable "little bones," or _ossicles_. They are chiefly three in number, and from their peculiar shapes bear the following names: _malleus_, or the mallet; _incus_, or the anvil; and _stapes_, or the stirrup. A fourth, the smallest bone in the body, in early life intervenes between the incus and stapes, but at a later period it becomes a part of the incus. It is called the _orbicular_ bone. Small as are these ossicles--and they, together, weigh only a few grains--they have their little muscles, cartilages, and blood-vessels, as perfectly arranged as the larger bones of the body. One end of the chain of ossicles, the mallet, is attached to the membrane of the tympanum, or outer drum-head, while the other end, the stirrup, is firmly joined by its foot-piece to a membrane in the opposite side of the cavity. The chain, accordingly, hangs suspended across the drum between the two membranes; and when the outer one vibrates under the influence of the sound-wave, the chain swings inward and transmits the vibration to the entrance of the inner ear. [Sidenote: 97. The Eustachian tube? Describe it, and state its use.] 97. The musical instrument, the drum, is not complete if the air within be perfectly confined: we therefore find in all instruments of this kind a small opening in the side, through which air may pass freely. By this means the pressure of the air upon the vellum which forms the head of the drum is made equal upon all sides, and the resonance of the drum remains unaffected by the varying density of the atmosphere. It will, therefore, emit its proper sound, whether it be struck in the rarified air of the mountain-top, or in the condensed air of a mine. The tympanum, {221} or drum of the ear, in like manner has an opening by means of which it communicates freely with the external air. This opening is a narrow canal, about an inch and a half long, called the _Eustachian tube_, after the name of its discoverer, Eustachius. [Illustration: FIG. 54.--SECTION OF THE RIGHT EAR. A, The Concha. B, Auditory Canal. C, Membrane of the Drum, (the lower half.) D, A small muscle. E, Incus, or Anvil. M, Malleus, or Mallet. I, Eustachian Tube. G, Semicircular Canals. H, Cochlea, or snail's shell.] [Sidenote: 98. What can you state of the action of the Eustachian tube?] 98. The course of this passage is indicated in Fig. 54, I, directed downward and inward: its other extremity opens into the upper part of the throat. The passage itself is ordinarily closed, but whenever the act of swallowing or gaping takes place, the orifice in the throat is stretched open, and the air of the cavity of the tympanum may then be renewed. Air may at will be made to enter through this tube, by closing the mouth and nose, and then trying {222} to force air through the latter. When this is done, a distinct crackle or clicking sound is perceived, due to the movement of the membranes, and of the little bones of the ear. [Sidenote: 99. What other purpose does the Eustachian tube serve? How is this shown? "Throat-deafness?" Primary use of the Eustachian tube?] 99. The Eustachian tube serves, also, as an escape-pipe for the fluids which form within the middle ear; and hence, when its lining membrane becomes thickened, in consequence of a cold, or sore throat, and the passage is thus more or less choked up, the fluids are unable to escape as usual, and therefore accumulate within the ear. When this takes place, the vibrations of the membrane are interfered with; the sounds heard appear muffled and indistinct; and a temporary difficulty of hearing, which is known as "throat-deafness," is the result. This result resembles the effect produced by interrupting the vibrations of a sonorous body, such as all are familiar with; if the finger be placed upon a piano-string or bell when it is struck, the proper sound is no longer fully and clearly emitted. But the primary use of this tube is to afford a free communication between the middle ear and the external atmosphere, and thus secure an equal pressure upon both sides of the membrane of the drum of the ear, however the density of the atmosphere may vary. If, from undue tension of the membranes, pain is experienced in the ears, when ascending into a rare atmosphere, as in a balloon, or descending into a dense one, as in a diving-bell, it may be relieved by repeating the act of swallowing, from time to time, in order that the inner and outer pressure may thus be promptly equalized. [Sidenote: 100. The essential part of the organ of hearing? Its location? Formation?] 100. THE INTERNAL EAR, OR LABYRINTH.--The most essential part of the organ of hearing is the distribution of the _auditory nerve_. This is found within the cavity of the internal ear, which, from its exceedingly tortuous shape, {223} has been termed the _labyrinth_ (see Fig. 53, C). This cavity is hollowed out in dense bone, and consists of three parts; the _vestibule_ (_a_), or ante-chamber, which is connected with the other two; the _cochlea_ (_b_), or snail's shell; and the three _semicircular canals_ (_c_). The manner in which the nerve of hearing is distributed is remarkable, and is peculiar to this nerve. In the vestibule and the canals its fibres are spread out over the inner surface, not of the bony cavity but of a membranous bag, which conforms to and partially fills that cavity; and which floats in it, being both filled and surrounded with a clear, limpid fluid. [Sidenote: 101. Where is the "ear-sand" found? Give the theory as to its use.] 101. A singular addition to the mechanism of hearing is observed within this membranous bag of the labyrinth. This consists of two small oval ear-stones, and a quantity of fine powder of a calcareous nature, which is called "ear-sand." When examined under the microscope, these sandy particles are seen to lie scattered upon and among the delicate filaments of the auditory nerve; and it is probable, that as the tremulous sound-wave traverses the fluid of the vestibule, the sand rises and falls upon the nerve filaments, and thus intensifies the sonorous impression. [Sidenote: 102. In the cochlea or snail's shell? "Key-board" in the internal ear? The vestibules? Semicircular canals?] 102. In the cochlea, or snail's shell, which contains the fluid, but no membrane, the nerve ramifies upon a spiral shelf, which, like the cochlea itself, takes two and a half turns, growing continuously smaller as it winds upward. As many as three thousand nerve fibres of different lengths have been counted therein; which, it has been thought, form the grand, yet minutely small key-board, upon which strike all the musical tones that are destined to be conveyed to the brain. The vestibule, it is also supposed, takes cognizance of noise as distinguished from musical sounds; while the office of the semicircular canals is, in part at least, to prevent internal echoes, or reverberations. {224} [Sidenote: 103. With what does the vestibule communicate? What is the theory by which sound is conducted to the brain?] 103. The vestibule communicates with the chain of bones of the middle ear by means of a small opening, called the "oval window," or _fenestra ovalis_. Across this window is stretched the membrane, which has already been alluded to as being joined to the stirrup-bone of the middle ear. Through this window, then, the sound-wave, which traverses the external and middle ear, arrives at last at the labyrinth. The limpid fluid which the latter contains, and which bathes the terminal fibres of the nerve of hearing, is thus agitated, the nerve-fibres are excited, and a sonorous impression is conducted to the brain, or, as we say, a sound is heard. [Sidenote: 104. The formation of the organ of hearing with a view to its protection?] 104. PROTECTION OF THE SENSE OF HEARING.--From what has been seen of the complicated parts which compose the organ of hearing, it is evident that while many of them possess an exquisite delicacy of structure, Nature has well and amply provided for their protection. We have observed the concealed situation of the most important parts of the mechanism of the ear, the length of its cavity, its partitions, the hardness of its walls, and its communication with the atmosphere; all these provisions rendering unnecessary any supervision or care on our part in reference to the interior of the ear. But in respect to its external parts, which are under our control and within the reach of harm, it is otherwise. We may both observe the dangers which threaten them, and learn the means necessary to protect them. [Sidenote: 105. Danger to which the hearing may be subjected? Advice?] 105. One source of danger to the hearing consists in lowering the temperature of the ear, especially by the introduction of cold water into the auditory canal. Every one is familiar with the unpleasant sensation of distension and the confusion of sounds which accompany the filling of the ear with water when bathing: the weight of the {225} water within it really distends the membrane, and the cold chills the adjacent sensitive parts. It is not surprising, therefore, that the frequent introduction of cold water and its continued presence in the ear enfeeble the sense of hearing. Care should be taken to remove water from the ear after bathing, by holding the head on one side, and, at the same time, slightly expanding the outer orifice, so that the fluid may run out. For a like reason, the hair about the ears should not be allowed to remain wet, but should be thoroughly dried as soon as possible. [Sidenote: 106. The general rule as to the use of water for the ear?] 106. It may be stated as a general rule, to which there are but few exceptions, that no cold liquid should ever be allowed to enter the ear. When a wash or injection is rendered necessary, it should always be warmed before use. The introduction of cold air is likewise hurtful, especially when it pours through a crevice directly into the ear, as it may often do through the broken or partially closed window of a car. The avoidance of this evil gives rise to another almost as great; namely, the introduction of cotton or other soft substances into the ear to prevent it from "catching cold." This kind of protection tends to make the part unnaturally susceptible to changes of temperature, and its security seems to demand the continued presence of the "warm" covering. As a consequence of its presence, sounds are not naturally conveyed, and the sensitiveness of the nerve of hearing is gradually impaired. [Sidenote: 107. Chief source of injury to the ear? Directions for removing foreign objects from the ear? Of a live insect?] 107. The chief source of injury, however, to the ear is from the introduction of solid substances into the auditory canal, with the design of removing insects or other foreign objects that have found their way into the ear; or with the design of scraping out the ear-wax. For displacing a foreign object, it is usually sufficient to syringe the ear gently with warm water, the head being so held that the {226} fluid easily escapes. If a live insect has gained entrance to the ear, it may first be suffocated by pouring a little oil upon it, and afterward removed by syringing the ear as just mentioned. 108. The removal of ear-wax is generally unnecessary; for, as we have before seen, Nature provides that the excess of it shall become dry, and then spontaneously fall out in the form of fine scales. The danger from the introduction of solid implements into the outer ear is chiefly found in the fact that the membrane which lies at the bottom of it is very fragile, and that any injury of it is liable to be permanent, and to permanently impair the hearing of the injured ear. QUESTIONS FOR TOPICAL REVIEW. _Give as full statements as you can on the following subjects_: 1. Production of sensation 177, 178 2. Variety of sensations 178, 179 3. General sensibility 179, 180 4. The sensation of pain 180 5. The uses of pain 180, 181, 182 6. Special sensation 182, 183 7. Organs of touch 183, 184 8. The sense of touch 184, 185, 186 9. The delicacy of touch 186, 187 10. Sensations of temperature and weight 187, 188 11. The organ of taste 188, 189 12. The sense of taste 189, 190 13. Relations of taste, etc. 190, 191 14. Influence of education, etc. 191, 192 15. The sense of smell 192, 193 16. The nerve of smell 193, 194 17. Uses of the sense of smell 194, 195 18. The sense of sight 196, 197 19. Light, and the optic nerve 197, 198 20. The organ of sight 198, 199 21. The orbits 199 22. The eyelids 200, 201 23. The lachrymal fluid 201, 202, 203 24. The eyeball 203, 204 25. The iris 205, 206 26. The retina 206, 207, 208, 209 27. The crystalline lens 209, 210 28. Uses of the lens 210, 211, 212 29. Long and short sight 212, 213 30. Function of accommodation 213, 214 31. Old sight, or presbyopia 215 32. Hearing and sound 215, 216, 217 33. The external ear 217, 218, 219 34. The middle ear 219-222 35. The internal ear 222, 223, 224 36. Protection of the sense of hearing 224, 225, 226 * * * * * {227} CHAPTER XI. THE VOICE. _Voice and Speech--The Larynx, or the Organ of the Voice--The Vocal Cords--The Laryngoscope--The Production of the Voice--The Use of the Tongue--The different Varieties of Voice--The Change of Voice--Its Compass--Purity of Tone--Ventriloquy._ [Sidenote: 1. The uttering of sounds by animals? How produced?] 1. VOICE AND SPEECH.--In common with the majority of the nobler animals, man possesses the power of uttering sounds, which are employed as a means of communication and expression. In man, these sounds constitute the voice; in the animals, they are designated as the cry. The song of the bird is a modification of its cry, which is rendered possible from the fact that its respiratory function is remarkably active. The sounds of the animals are generally, but not always, produced by means of their breathing organs. Among the insects, they are sometimes produced by the extremely rapid vibrations of the wings in the act of flight, as in the case of the musquito; or they are produced by the rubbing together of hard portions of the external covering of the body, as in the cricket. Almost all kinds of marine animals are voiceless. The tambour-fish and a few others have, however, the power of making a sort of noise in the water. [Sidenote: 2. The evidence of man's superior endowment? What is stated of the idiot? Parrot? Raven?] 2. But man alone possesses the faculty of speech, or the power to use articulate sounds in the expression of ideas, and in the communication of mind with mind. Speech is thus an evidence of the superior endowment of man, and involves the culture of the intellect. An idiot, while he {228} may have complete vocal organs and full power of uttering sounds or cries, is entirely incapable of speech; and, as a rule, the excellence of the language of any people will be found to be proportional to their development of brain. Man, however, is not the only being that has the power to form articulate sounds, for the parrot and the raven may also be taught to speak by rote; but man alone attaches meaning to the words and phrases he employs. [Sidenote: 3. Speech and hearing? A deaf child? Person having "no ear for music?" Impaired hearing? What do the examples show?] 3. Speech is intimately related to the sense of hearing. A child born deaf is, of necessity, dumb also; not because the organs of speech are imperfect, for he can utter cries and may be taught to speak, and even to converse in a rude and harsh kind of language; but because he can form no accurate notion of sound. And a person, whose hearing is not delicate, or as it is commonly expressed, who "has no ear for music," cannot sing correctly. A person who has impaired hearing commonly talks in an unnaturally loud and monotonous voice. These examples show the necessary relation of intelligence and the sense of hearing with that form of articulate voice, which is termed speech. [Sidenote: 4. Organ of the voice? Where situated? Of what is its framework composed?] 4. THE ORGAN OF THE VOICE.--The essential organ of the voice is the Larynx. This has been previously alluded to in its relation to the function of respiration; and, in the chapter on that subject, are figured the front view of that organ (Fig. 35), and its connection with the trachea, tongue, and other neighboring parts (Fig. 38). It is situated at the upper part of the neck, at the top of the trachea, or tube by which air passes into and out of the lungs. The framework of the larynx is composed of four cartilages, which render it at once very strong and sufficiently flexible to enable it to move according to the requirements of the voice. {229} [Illustration: FIG. 55. SECTION OF THE LARYNX AND TRACHEA. A, The Epiglottis. B, The Thyroid Cartilage. C, Arytenoid Cartilage. D, Ventricle of the Larynx. E, Cricoid Cartilage. F, Right Vocal Cord. H, The Trachea.] [Sidenote: 5. Names, formation, and situation of the cartilages?] 5. The names of the cartilages are (1) the _thyroid_, which is a broad thin plate, bent in the middle and placed in the central line of the front part of the neck, where it is known as the _pomum Adami_, or Adam's apple (Fig. 55, B), and where it may be felt moving up and down with each act of swallowing; (2) the _cricoid_, which is shaped like a seal ring, with the broad part placed posteriorly (Fig. 55, E). At the top of the cricoid cartilage are situated the two small _arytenoid_ cartilages, the right one of which is shown in Fig. 55, C. These latter little organs are much more movable than the other two, and are very important in the production of the voice. They have a true ball and socket joint, and several small muscles which contract and relax with as perfect regularity and accuracy as any of the larger muscles of the body. [Sidenote: 6. Lining of the interior of the larynx? The epiglottis?] 6. The interior of the larynx is lined with a very sensitive mucous membrane, which is much more closely adherent to the parts beneath than is usually the case with membranes of this description. The epiglottis (A), consisting of a single leaf-shaped piece of cartilage, is attached to the front part of the larynx. It is elastic, easily moved, and fits accurately over the entrance to the air-passages below it. Its office is to guard these delicate passages and the lungs against the intrusion of food and other foreign {230} articles, when the act of swallowing takes place. It also assists in modifying the voice. [Sidenote: 7. Where are the vocal cords? The false cords? The true cords?] 7. THE VOCAL CORDS.--Within the larynx, and stretched across it from the thyroid cartilage in front to the arytenoid cartilages behind, are placed the two sets of folds, called the vocal cords. The upper of these, one on each side, are the false cords, which are comparatively fixed and inflexible. These are not at all essential to the formation of vocal sounds, for they have been injured, in those lower animals whose larynx resembles that of man, without materially affecting their characteristic cries. Below these, one on each side, are the true vocal cords (Fig. 55, F), which pursue a similar direction to the false cords, namely, from before backward. But they are composed of a highly elastic, though strong tissue, and are covered with a thin, tightly-fitting layer of mucous membrane. Their edges are smooth and sharply defined, and when they meet, as they do in the formation of sounds, they exactly match each other. [Sidenote: 8. Where is the ventricle of the larynx? The essentials to the formation of the tones and modulation of the voice?] 8. Between the true and false vocal cords is a depression on each side, which is termed the ventricle of the larynx (Fig. 55, D). The integrity of these true cords, and their free vibration, are essential to the formation of the tones and the modulation of the natural voice. This is shown by the fact that, if one or both of these cords are injured or become diseased, voice and speech are compromised; or when the mucous membrane covering them becomes thickened, in consequence of a cold, the vocal sounds are rendered husky and indistinct. When an opening is made in the throat below the cords, as not infrequently happens in consequence of an attempt to commit suicide, voice is impossible except when the opening is closed by external pressure. {231} [Illustration: FIG. 56. A VIEW OF THE VOCAL CORDS BY MEANS OF THE LARYNGOSCOPE.] [Sidenote: 9. Variation in the interval between the true cords of the voice? Experiment with the mirror?] 9. The interval or space between the true cords of the voice is constantly varying, not only when their vocal function is in exercise, but also during the act of respiration. Every time the lungs are inflated, the space increases to make wide the entrance for the air; and diminishes slightly during expiration. So that these little cords move gently to and fro in rhythm with the expansion and contraction of the chest in breathing. These movements and others may be seen to take place, if a small mirror attached to a long handle be placed back into the upper part of the throat; the handle near the mirror must be bent at an angle of 45°, so that we may look "around the corner," so to speak, behind the tongue. The position which the mirror must assume will be understood by reference to Fig. 38. A view of what may be seen under favorable circumstances, during tranquil inspiration is represented in Fig. 56. The vocal cords are there shown as narrow, white bands, on each side of the central opening, and since the image is inverted, the epiglottis appears uppermost. The rings partly seen through the opening belong to the trachea. This little mirror is the essential part {232} of an instrument, which is called the laryngoscope, and, simple as it may seem, it is accounted one of the most valuable of the recently invented appliances of the medical art. [Sidenote: 10. The formation of true vocal tones?] 10. THE PRODUCTION OF THE VOICE.--During ordinary tranquil breathing no sound is produced in the larynx, true vocal tones being formed only during forcible expiration, when, by an effort of the will, the cords are brought close together, and are stretched so as to be very tense. The space between them is then reduced to a narrow slit, at times not more than 1/100 of an inch in width; and the column of expired air being forced through it causes the cords to vibrate rapidly, like the strings of a musical instrument. Thus the voice is produced in its many varieties of tone and pitch; its intensity, or loudness, depending chiefly upon the power exerted in expelling the air from the lungs. When the note is high, the space is diminished both in length and width; but when it is low, the space is wider and longer (Fig. 57, B, C), and the number of vibrations is fewer within the same period of time. [Illustration: FIG. 57. THE DIFFERENT POSITIONS OF THE VOCAL CORDS. A, The position during inspiration. B, In the formation of low notes. C, In the formation of high notes.] [Sidenote: 11. To what is the personal quality of the voice mainly due? What aids are there?] 11. The personal quality of the voice, or that which enables us to recognize a person by his speech, is mainly due to the peculiar shape of the throat, nose, and mouth, and {233} the resonance of the air contained within those cavities. The walls of the chest and the trachea take part in the resonance of the voice, the air within them vibrating at the same time with the parts above them. This may be tested by touching the throat or breast-bone, when a strong vocal effort is made. The teeth and the lips also are important, as is shown by the unnatural tones emitted by a person who has lost the former, or by one who is affected with the deformity known as "hare-lip." The tongue is useful, but not indispensable to speech; the case of a woman is reported, from whom nearly the whole tongue had been torn out, but who could, nevertheless, speak distinctly and even sing. [Sidenote: 12. Varieties of voice? The baritone? The voice in early youth?] 12. THE VARIETIES of voice are said to be four in number; two, the bass and tenor, belonging to the male sex; and two, the contralto or alto, and soprano, peculiar to the female. The baritone voice is the name given to a variety intervening between the bass and tenor. In man, the voice is strong and grave; in woman, soft and high. In infancy and early youth, the voice is the same in both sexes, being of the soprano variety: that of boys is both clear and loud, and being susceptible of considerable training, is highly prized in the choral services of the church and cathedral. At about fourteen years of age the voice is said to change; that is, it becomes hoarse and unsteady by reason of the rapid growth of the larynx. In the case of the girl, the change is not very marked, except that the voice becomes stronger and has a wider compass; but in the boy, the larynx nearly doubles its size in a single year, the vocal cords grow thicker, longer, and coarser, and the voice becomes masculine in character. During the progress of this change, the use of the voice in singing is injudicious. [Sidenote: 13. The range of the voice? Result of careful training of the vocal organs?] 13. The ordinary range of each of the four varieties of {234} the voice is about two octaves; but this is exceeded in the case of several celebrated vocalists. Madame Parepa-Rosa has a compass of three full octaves. When the vocal organs have been subjected to careful training, and are brought under complete control of the will, the tension of the cords become exact, and their vibrations become exceedingly precise and true. Under these circumstances the voice is said to possess "purity" of tone, and can be heard at a great distance, and above a multitude of other sounds. The power of a pure voice to make itself heard was recently exemplified in a striking manner: at a musical festival held in an audience-room of extraordinary size, and amid an orchestra of a thousand instruments and a chorus of twelve thousand voices, the artist named above also sang; yet such was the purity and strength of her voice that its notes could be clearly heard rising above the vast waves of sound produced by the full accompaniment of chorus and orchestra. [Sidenote: 14. The production of the articulate sounds? What experiment is mentioned?] 14. In the production of the articulate sounds of speech, the larynx is not directly concerned, but those sounds really depend upon alterations in the shape of the air-passages above that organ. That speech is not necessarily due to the action of the larynx is proven by the following simple experiment. Let an elastic tube be passed through the nostril to the back of the mouth. Then, while the breath is held, cause the tongue, teeth, and lips to go through the form of pronouncing words, and at the same time, let a second person blow through the tube into the mouth. Speech, pure and simple, or, in other words, a whisper is produced. Still further continue the experiment, while permitting vocal sounds to be made, and there will be produced a loud and whispering speech at the same moment; thus showing that voice and speech are the result of two distinct acts. Sighing, in like manner, is {235} produced in the mouth and throat; if, however, a vocal sound be added, the sigh is changed into a groan. [Sidenote: 15. What is ventriloquism? Indication of the original meaning of the word? How are the ventriloquous sounds produced?] 15. VENTRILOQUISM is a peculiar modification of natural speech, which consists in so managing the voice that words and sounds appear to issue, not from the person, but from some distant place, as from the chimney, cellar, or the interior of a chest. The original meaning of the word ventriloquism (that is, speaking from the belly), indicates the early belief that this mode of speech was dependent upon the possession and use of some special organ besides the larynx and mouth; but at the present time, it is known that it is produced by these organs alone, and that the sources of deception consist on the part of the performer, in the dexterous management of the voice, together with a talent for mimicry; and, on the part of the auditory, in the liability of the sense of hearing to error in respect to the direction of sounds. The ventriloquist not only seems to "throw his voice," as it is said, or simulates the sound as it usually appears at a distance with but little motion of the lips and face, but he imitates the voices of an infant and of a feeble old man, of a drunken man disputing with an exasperated wife, the broken language of a foreigner, the cry of an animal in distress, demonstrating that the performer must be proficient in the art of mimicry. Ventriloquism was known to the ancient Romans and Greeks; and it is thought that the mysterious responses that were said to issue from the sacred trees and shrines of the oracles at Dodona and Delphi, were really uttered by priests who had the power of producing this form of speech. * * * * * {236} CHAPTER XII. THE USE OF THE MICROSCOPE IN THE STUDY OF PHYSIOLOGY. [Sidenote: 1. The will of the Creator, by what obeyed? The power of a muscle? Amount of duty performed by the liver?] 1. THE LAW OF THE TISSUES.--The will of an infinite Creator is obeyed by atoms as well as by worlds. He has seen fit to commit all the functions of life to structures or tissues so small as to be invisible to the naked eye. A muscle, for example, as we have already learned, is composed of innumerable filaments, visible only by the aid of the microscope; and the power of the muscular mass is but the sum of the contractile power of the filaments which enter into its composition. Again, each cell of the liver, invisible to unassisted sight, is a secreting organ, and the liver performs as much duty as the sum of these minute organs renders possible and no more. [Sidenote: 2. Necessity for using the microscope? The advantages gained by its use?] 2. THE NECESSITY OF THE MICROSCOPE.--If, therefore, we would know the real structure of the human body, we must make use of the microscope. We are not at liberty either to use it or not; we _must_ have recourse to it in order to obtain a real knowledge of the human body. Our eyes are constructed for the common offices of life, to provide for our wants and guard us from the ordinary sources of danger; but by arming them with _lenses_, the real structure of plants and animals is revealed to our intelligence; and enemies, otherwise invisible, that lie in wait in the air we breathe, and in our daily food and drink, to destroy life, are guarded against. [Sidenote: 3. What are convex lenses? Kind of lenses used in microscopes? Experiment? Picture thrown upon the eye? Derivation of the word microscope?] 3. CONVEX LENSES, or magnifying glasses, are disks of glass or other transparent substance, which have the {237} property of picturing upon the retina of the eye an image of an object larger than the image produced there without their aid. The glasses used in microscopes are either double convex lenses (_a_) or plano-convex lenses (_b_). If a double convex lens or a plano-convex one be placed over a hole in the shutter of a darkened room, or over the key-hole of a door, and a piece of paper be held at a proper distance, a picture of all objects in front of the lens will be thrown on the paper, as in the camera-obscura or the magic-lantern. Now, in the same manner, a lens throws a picture of objects to which it is directed on the retina of the eye, and when that picture is larger than the image made in the eye by the object, without the aid of the lens, it is magnified, or the lens has served as a _microscope_, so called, from its use in seeing small objects, from _mikros_, small, and _skopeo_, to see. [Illustration] [Sidenote: 4. Kinds of microscope? What are simple microscopes?] 4. DIFFERENT KINDS OF MICROSCOPES.--Microscopes are either _simple_ or _compound_. The glasses of magnifying spectacles, like those commonly used by aged persons, are simple microscopes. Magnifying glasses, mounted in frames such as are for sale by opticians and others, for the detection of counterfeit money, are simple microscopes, and are useful in studying the coarser structure of plants and animals. [Sidenote: 5. Construction of the most powerful simple microscopes? In practice? A doublet? Triplet? Why are compound microscopes superior to simple ones?] 5. The most powerful simple microscopes are made by melting in a flame a thread of spun glass, so as to form a {238} minute globule or bead, which, when set in a piece of metal and used to examine objects on a plate of glass held up to the light, gives a high magnifying power. In practice, however, it is found better to use several magnifying glasses of moderate power, than a simple lens alone of high power. A combination of two lenses is called a _doublet_--of three, a _triplet_. All _simple_ microscopes throw an enlarged image of the object upon the retina. _Compound_ microscopes are so constructed that the enlarged image of an object is again magnified by a second lens, and hence their magnifying power is vastly superior to that of simple microscopes. [Sidenote: 6. Explain, by means of the diagram, the action of the compound microscope.] 6. The accompanying diagrams will explain the action of the compound microscope compared with that of the simple microscope. In Fig. 58, which represents the working of the simple microscope, the rays from the object (_a b_), passing through the lens (L), form an image (_a' b'_) in the retina of the eye (E), and as all images are inverted in the eye, the object is seen as all other objects are, and appears erect. In Fig. 59 is seen the action of the compound microscope. An inverted image (_a' b'_) of the object (_a b_) is magnified by the second lens (L'), and an erect image is thrown upon the retina, which, as all other objects seen erect with the naked eye are inverted, gives to the image a contrary direction, or inverts it to the mind. [Illustration: FIG. 58.--SIMPLE MICROSCOPE.] {239} [Sidenote: 7. Portions, in a compound microscope? The glasses?] 7. A COMPOUND MICROSCOPE consists of two portions: the optical portion, or the lenses, and the mechanical portion, or the instrument which bears the lenses. The glasses of a compound microscope are two: the _object-glass_ (D), Fig. 60, and the lower lens of Fig. 59, and the _ocular_ or _eye-piece_ (A), Fig. 60, and the upper piece of Fig. 59. Both the object-glass and the eye-piece may, and usually do, consist of more than one lens, for, as previously mentioned, better results are obtained by a combination of lenses of moderate power than by single lenses of high power and great curvature. [Sidenote: 8. How to choose a microscope? How to use it?] 8. HOW TO CHOOSE AND USE A MICROSCOPE.--No attractiveness in the mechanical part of a microscope can compensate for inferior lenses; and the very first consideration in the choice of an instrument should be the excellence of the optical part of the instrument. In the use of the instrument, care should be exercised to keep the lenses clean, free from dust, not to press the object-glass upon the object under observation, and not to wet it in the water in which most objects are examined. A good microscope requires its own table; and when not in use should be covered by a bell glass or a clean linen cloth. [Illustration: FIG. 59. COMPOUND MICROSCOPE.] {240} [Illustration: FIG. 60. A, Eye-piece. B, Body. C, Collar. D, Object-glass. E, Stage. F, Hinge. G, Mirror. H, Stand.] [Sidenote: 9. The characteristics of the best instrument? What special requisites should be insisted upon? Why, as to a horizontal stage?] 9. The mechanical portion of the instrument varies greatly in different instruments. That one is the best which is simplest, the most solid and easily managed. The stage (E), upon which the object is placed, should not be movable: it should be solid and firm. The screw by which the focal distance is adjusted, and which {241} is in constant use, should be so placed that it can be worked by the hand resting on the table: otherwise fatigue is soon induced. The direction of the tube carrying the glasses should be perpendicular, and the stage therefore horizontal. Most objects in human anatomy are examined in water or in other liquids, or they are themselves liquids; hence an oblique stage is often inconvenient. [Illustration: FIG. 61.] {242} [Sidenote: 10. Slides? Covers, square and circular? How kept?] 10. ADDITIONAL APPARATUS.--As almost all objects in human anatomy are examined by transmitted light thrown up from the mirror (G, Fig. 60) beneath the stage through the object to the eye, they must be placed upon strips of clear glass about three inches long and one inch wide, commonly called "slides." These should be procured with the microscope. Again, most objects seen with high powers require to be covered with a thin plate of glass, very properly called a "cover," that the moisture of the specimen may not tarnish the object-glass. Square or circular covers of very thin glass are therefore provided; and a good supply of these should be always on hand. These glasses should be kept in a covered dish filled with a mixture of alcohol and water. Simple water will not remove the fatty matter which exists in all animal tissues, and, therefore, the glasses cannot be thoroughly cleaned with it alone. [Sidenote: 11. Cleaning the glasses? Knives, scissors, etc.? Various liquids?] 11. When glasses are required for use, they should be removed from the liquid and wiped clean and dry with a soft linen handkerchief. Delicate knives, scissors, needles mounted in handles, forceps, pipettes or little tubes for taking up water, should be obtained; these are essential to all microscopical study. The table should be supplied with glass-stoppered bottles containing the various liquids ordinarily used in the study of physiology. Thus, tincture of iodine is indispensable in studying vegetable structure, acetic acid in the study of animal tissues; and other articles will have to be added from time to time, as your progress in study demands them. {243} [Sidenote: 12. Bodies, in air and water? The examination of starch?] 12. PRELIMINARY STUDIES.--In order to prepare the way for the study of any department of science with the aid of the microscope--for the microscope is but an eye, and can be turned in almost any direction for purposes of investigation--it is necessary to become acquainted with the many objects which are liable to complicate the examination of particular structures. Both air and water are full of floating bodies, and the most common of these should first occupy the attention. In the city, particles of starch are always floating in the air. Take a very minute portion of wheat flour, place it in the middle of a clean glass "slide," drop upon it a drop of pure water, cover it with a plate of thin glass, and examine it with a power of from one hundred to six hundred diameters. It will be found to be composed of minute grains or granules, the largest of which are made up of coats or layers, like an onion, arranged around a central spot called the _hilum_. [Sidenote: 13. The examination with solution of iodine? Advice respecting other articles?] 13. Make another preparation in the same manner, and, after adding the water and before covering with the thin glass cover, add a small drop of a solution of iodine. Now, upon examining the specimen, every grain will be seen to be of a beautiful deep blue color. After thus studying wheat starch, the starch of Indian corn, of arrowroot, and of various grains should be examined in like manner, and their resemblances and differences noted. The granules of potato-starch are as distinctly marked as any. (See Fig. 15, page 61.) [Sidenote: 14. Directions for examining cotton and other fibres? Vegetable hairs?] 14. Fibres of cotton, lint, and wool are liable to be found in every specimen prepared for microscopical examination. In order to study these, any cotton, woollen, or linen fabric, or garment, may be scraped, and the scrapings placed on a piece of glass moistened with water, covered with the thin glass plate or cover as before, and {244} examined with the same magnifying power, namely, from one hundred to six hundred diameters. Vegetable hairs or down are constantly floating in air and water. These are of very various forms, are simple or grouped, and form very interesting objects of study. They are readily procured from the epidermis or outer membrane of the leaves or stems of plants, by section with a delicate knife. [Sidenote: 15. Directions for examining various tissues? Down of moths, and other structures?] 15. The tissues of plants, epidermis, ducts, and woody fibres are constantly found in microscopic preparations. They may be studied in delicate sections made with a sharp knife, or by tearing vegetable tissues apart with needles. The down of moths, the hairs of different animals, the fibres of paper, the most common animalcules in water, the dust of shelves, and generally the structures found in all vegetable and animal substances by which we are surrounded, should be studied as a preliminary to any special line of microscopical investigation. [Sidenote: 16. Directions for examining a drop of blood?] 16. THE STUDY OF HUMAN TISSUES.--When this has been done and familiarity with the use of the instrument has been obtained, proceed to the study of the human body, for human physiology is our subject. If the end of the finger be pricked with a pin, a drop of blood may be procured for examination. Place this on one of the glass slides, cover it with a thin piece of glass, press down the cover so as to make a thin layer, and then examine with the magnifying power just mentioned. Do not add water, for that will cause the blood corpuscles to disappear. If the drop of blood is placed under the microscope at once after being drawn from the finger, most interesting phenomena will be observed. The red corpuscles will be seen to arrange themselves in rows, like piles of coin, while the blood is coagulating. The spherical, white corpuscles will {245} be left out of the rows of red disks, and, if the highest power be used, will be seen to change their shape constantly. [Sidenote: 17. Examination of the scales of the mouth? Dandruff?] 17. If you scrape with a dull knife the inside of the cheek, the flattened scales of "pavement epithelium," or of the insensible covering which, analogous to the scarf-skin on the outer surface of the body, lines the cavities of its interior, may be readily studied. They have the appearance of transparent tiles, each enclosing a round or oval body, called its nucleus. Dandruff and the scrapings from the skin of the body are composed of scales like those of the mouth, but they differ somewhat in being hardened by horny matter, and in having a very faint central body or nucleus. [Sidenote: 18. In what, as respects the tissues, do the warm blooded animals differ? Statement of Milne Edwards?] 18. THE TISSUES OF THE INFERIOR ANIMALS.--The warm-blooded animals do not differ in the tissues, or microscopic structures, that compose them, but only in the amount and arrangement of these tissues. Milne Edwards says these tissues "do not differ much in different animals, but their mode of association varies; and it is chiefly by reason of the differences in the combination of these associations in various degrees, that each species possesses the anatomical properties and characters which are peculiar to it." [Sidenote: 19. How to procure materials for the study of the tissues of man?] 19. Hence the butcher's stall will furnish all the materials for the study of the microscopic tissues. The structure of the heart, lungs, liver, brain, and muscle may all be studied, and well studied, by using minute pieces of the flesh of the lower animals, especially of the quadrupeds. Such portions of these animals as are not exposed for sale can be readily obtained by order from the slaughter-house. To examine with the powers of which we have been speaking, it is only necessary to cut off {246} exceedingly small pieces, tear them apart with needles, or make very delicate sections with a sharp knife. 20. INCENTIVES TO STUDY.--A complete knowledge of all minute structures is not to be expected at once, for you are here introduced into a new realm of Nature, a world of little things as vast, as wonderful, and as carefully constructed as the starry firmament,--that other realm of grand objects which the astronomer nightly scans with the telescope. It will not appear singular, therefore, if, at first, you feel strange and awkward in this new creation. With a little perseverance, however, and with the attention directed toward simple objects at the outset, it will not be long before an increasing experience will engender confidence. 21. If to all this there be added an enthusiastic study of the standard authorities on the subject, the rate of progress will be by so much the more rapid. As compared with similar studies, few possess more interest than microscopy, and to the one who pursues it with fondness, it constantly affords sources of pleasure and agreeable surprises; and in the end, often leads to new and valuable additions to the sum of human knowledge. The depths which the microscope is employed to fathom are no more completely known, than are the heights above us explored and comprehended by the astronomer. QUESTIONS FOR TOPICAL REVIEW. _State what you can on the following subjects_: 1. Voice and speech 227, 228 2. The organ of the voice 228, 229 3. The vocal cords 230, 231 4. The production of the voice 232, 233 5. The varieties of voice 233, 234 6. Ventriloquism 235 7. The law of the tissues 236 8. Necessity of the microscope 236 9. Convex lenses 236, 237 10. Kinds of microscope 237, 238 11. Choosing a microscope 239, 242 12. Preliminary studies 243, 244 13. The study of human tissues 244 14. The study of the inferior animals 245 * * * * * {247} APPENDIX. ------o------ POISONS AND THEIR ANTIDOTES. Accidents from poisoning are of such frequent occurrence, that every one should be able to administer the more common antidotes, until the _services of a physician can be obtained_. As many poisons bear a close resemblance to articles in common use, no dangerous substance should be brought into the household without having the word _poison_ plainly written or printed on the label; and any package, box, or vial, without a label, should be at once destroyed, if the contents are not positively known. When a healthy person is taken severely and _suddenly_ ill _soon after some substance has been swallowed_, we may suspect that he has been poisoned. In all cases where poison has been taken into the stomach, it should be quickly and thoroughly evacuated by some active emetic, which can be speedily obtained. This may be accomplished by drinking a tumblerful of warm water, containing either a tablespoonful of powdered mustard or of common salt, or two teaspoonfuls of powdered alum in two tablespoonfuls of syrup. When vomiting has already taken place, it should be maintained by copious draughts of warm water or mucilaginous drinks, such as gum-water or flaxseed tea, and tickling the throat with the finger until there is reason to believe that all the poisonous substance has been expelled from the stomach. The following list embraces only the more common poisons, together with such antidotes as are usually at hand, to be used until the physician arrives. POISONS. ACIDS.--_Hydrochloric acid_; _muriatic acid_ (spirits of salt); _nitric acid_ (aqua fortis); _sulphuric acid_ (oil of vitriol). ANTIDOTE.--An antidote should be given at once to neutralize the acid. Strong soapsuds is an efficient remedy, and can always be obtained. It should be followed by copious draughts of warm water or flaxseed tea. Chalk, magnesia, soda or saleratus (with water) or {248} lime-water, are the best remedies. When sulphuric acid has been taken, water should be given sparingly, because, when water unites with this acid, intense heat is produced. _Oxalic acid._ ANTIDOTE.--Oxalic acid resembles Epsom salts in appearance, and may easily be mistaken for it. The antidotes are magnesia, or chalk mixed with water. PRUSSIC ACID; _oil of bitter almonds_; _laurel water_; _cyanide of potassium_ (used in electrotyping). ANTIDOTE.--Cold douche to the spine. Chlorine water, or water of ammonia largely diluted, should be given, and the vapor arising from them may be inhaled. ALKALIES AND THEIR SALTS.--AMMONIA (hartshorn), _liquor or water of ammonia_. POTASSA:--_caustic potash_, _strong ley_, _carbonate of potassa_ (pearlash), _nitrate of potassa_ (saltpetre). ANTIDOTE.--Give the vegetable acids diluted, as weak vinegar, acetic, citric, or tartaric acids dissolved in water. Castor oil, linseed oil, and sweet oil may also be used; they form soaps when mixed with the free alkalies, which they thus render harmless. The poisonous effects of saltpetre must be counteracted by taking mucilaginous drinks freely, so as to produce vomiting. ALCOHOL.--_Brandy_, _wine_; _all spirituous liquors_. ANTIDOTE.--Give as an emetic ground mustard or tartar emetic. If the patient cannot swallow, introduce a stomach pump; pour cold water on the head. GASES.--_Chlorine_, _carbonic acid gas_, _carbonic oxide_, _fumes of burning charcoal_, _sulphuretted hydrogen_, _illuminating or coal-gas_. ANTIDOTE.--For poisoning by chlorine, inhale, cautiously, ammonia (hartshorn). For the other gases, cold water should be poured upon the head, and stimulants cautiously administered; artificial respiration. (See _Marshall Hall's Ready Method_, page 250.) METALS.--_Antimony_, _tartar emetic_, _wine of antimony_, etc. ANTIDOTE.--If vomiting has not occurred, it should be produced by tickling the throat with the finger or a feather, and the abundant use of warm water. Astringent infusions, such as common tea, oak bark, and solution of tannin, act as antidotes. ARSENIC.--_White arsenic_, _Fowler's solution_, _fly-powder_, _cobalt_, _Paris green_, etc. ANTIDOTE.--Produce vomiting at once with a tablespoonful or two of powdered mustard in a glass of warm water, or with ipecac. The antidote is hydrated peroxide of iron. If Fowler's solution has been taken, lime-water must be given. {249} COPPER.--_Acetate of copper_ (verdigris), _sulphate of copper_ (blue vitriol), food cooked in dirty _copper vessels_, or pickles made green by _copper_. ANTIDOTE.--Milk or white of eggs, with mucilaginous drinks (flaxseed tea, etc.), should be freely given. IRON.--_Sulphate of iron_ (copperas), etc. ANTIDOTE.--Carbonate of soda in some mucilaginous drink, or in water, is an excellent antidote. LEAD.--_Acetate of lead_ (sugar of lead), _carbonate of lead_ (white lead), water kept in _leaden pipes_ or _vessels_, food cooked in _vessels_ glazed with _lead_. ANTIDOTE.--Induce vomiting with ground mustard or common salt in warm water. The antidote for soluble preparations of lead is Epsom salts; for the insoluble forms, sulphuric acid largely diluted. MERCURY.--_Bichloride of mercury_ (corrosive sublimate), _ammoniated mercury_ (white precipitate), _red oxide of mercury_ (red precipitate), _red sulphuret of mercury_ (vermilion). ANTIDOTE.--The white of eggs, or wheat flour beaten up with water and milk, are the best antidotes. SILVER.--_Nitrate of silver_ (lunar caustic). ANTIDOTE.--Give a teaspoonful of common salt in a tumbler of water. It decomposes the salts of silver and destroys their activity. ZINC.--_Sulphate of zinc_, etc. (white vitriol). ANTIDOTE.--The vomiting may be relieved by copious draughts of warm water. The antidote is carbonate of soda administered in water. NARCOTIC POISONS.--_Opium_ (laudanum, paregoric, salts of morphia, Godfrey's cordial, Dalby's carminative, soothing syrup, cholera mixtures), _aconite_, _belladonna_, _hemlock_, _stramonium_, _digitalis_, _tobacco_, _hyosciamus_, _nux vomica_, _strychnine_. ANTIDOTE.--Evacuate the stomach by the most active emetics, as mustard, alum, or sulphate of zinc. The patient should be kept in motion, and cold water dashed on the head and shoulders. Strong coffee must be given. The physician will use the stomach pump and electricity. In poisoning by nux vomica or strychnine, etc., chloroform or ether should be inhaled to quiet the spasms. IRRITANT VEGETABLE POISONS.--_Croton oil_, _oil of savine_, _poke_, _oil of tansy_, etc. ANTIDOTE.--If vomiting has taken place, it may be rendered easier by copious draughts of warm water. But if symptoms of insensibility have come on without vomiting, it ought to be immediately excited by ground mustard mixed with warm water, or some other active emetic {250} and after its operation an active purgative should be given. After evacuating as much of the poison as possible, strong coffee or vinegar and water may be given with advantage. POISONOUS FISH.--_Conger eel_, _mussels_, _crabs_, etc. ANTIDOTE.--Evacuate, as soon as possible, the contents of the stomach and bowels by emetics (ground mustard mixed with warm water or powdered alum), and castor oil, drinking freely at the same time of vinegar and water. Ether, with a few drops of laudanum mixed with sugar and water, may afterward be taken freely. POISONOUS SERPENTS.--ANTIDOTE.--A ligature or handkerchief should be applied moderately tight above the bite, and a cupping-glass over the wound. The patient should drink freely of alcoholic stimulants containing a small quantity of ammonia. The physician may inject ammonia into the veins. POISONOUS INSECTS.--_Stings of scorpion_, _hornet_, _wasp_, _bee_, etc. ANTIDOTE.--A piece of rag moistened with a solution of carbolic acid may be kept on the affected part until the pain is relieved; and a few drops of carbolic acid may be given frequently in a little water. The sting may be removed by making strong pressure around it with the barrel of a small watch-key. DROWNING. MARSHALL HALL'S "READY METHOD" of treatment in asphyxia from drowning, chloroform, coal gas, etc. 1st. Treat the patient _instantly on the spot_, in the _open air_, freely exposing the face, neck, and chest to the breeze, except in severe weather. 2d. In order _to clear the throat_, place the patient gently on the face, with one wrist under the forehead, that all fluid, and the tongue itself, may fall forward, and leave the entrance into the windpipe free. 3d. _To excite respiration_, turn the patient slightly on his side, and apply some irritating or stimulating agent to the nostrils, as _veratrine_, _dilute ammonia_, etc. 4th. Make the face warm by brisk friction; then dash cold water upon it. 5th. If not successful, lose no time; but, _to imitate respiration_, place the patient on his face, and turn the body gently, but completely _on the side, and a little beyond_; then again on the face, and so on, alternately. Repeat these movements, deliberately and perseveringly, {251} _fifteen times only_ in a minute. (When the patient lies on the thorax, this cavity is _compressed_ by the weight of the body, and _ex_piration takes place. When he is turned on the side, this pressure is removed, and _in_spiration occurs.) 6th. When the prone position is resumed, make a uniform and efficient pressure _along the spine_, removing the pressure immediately, before rotation on the side. (The pressure augments the _ex_piration: the rotation commences _in_spiration.) Continue these measures. 7th. Rub the limbs _upward_, with _firm pressure_ and with _energy_. (The object being to aid the return of venous blood to the heart.) 8th. Substitute for the patient's wet clothing, if possible, such other covering as can be instantly procured, each bystander supplying a coat or cloak, etc. Meantime, and from time to time, _to excite inspiration_, let the surface of the body be _slapped_ briskly with the hand. 9th. Rub the body briskly till it is dry and warm, then dash _cold_ water upon it, and repeat the rubbing. Avoid the immediate removal of the patient, as it involves a _dangerous loss of time_--also, the use of bellows, or any _forcing_ instrument; also, the _warm bath_, and _all rough treatment_. * * * * * {252} GLOSSARY. ------o------ AB-DO´MEN (Latin _abdo_, to conceal). The largest cavity of the body containing the liver, stomach, intestines, etc.; the belly. AB-SOR´BENTS (L. _ab_ and _sorbeo_, to suck up). The vessels which take part in the process of absorption. AB-SORP´TION. The process of sucking up fluids by means of an animal membrane. AC-COM-MO-DA´TION of the Eye. The alteration in the shape of the crystalline lens, which accommodates or adjusts the eye for near and remote vision. AC´ID, LACTIC (L. _lac_, milk). The acid ingredient of sour milk; the gastric juice also contains it. AL-BU´MEN, or Albumin (L. _albus_, white). An animal substance resembling white of egg. AL-BU´MI-NOSE (from _albumen_). A soluble animal substance produced in the stomach by the digestion of the albuminoid substances. AL-BU´MIN-OID substances. A class of proximate principles resembling albumen; they may be derived from either the animal or vegetable kingdoms. AL´I-MENT (L. _alo_, to nourish). That which affords nourishment; food. AL-I-MENT´A-RY CA-NAL (from _aliment_). A long tube in which the food is digested, or prepared for reception into the system. AN-ÆS-THET´ICS (Greek, [Greek: an], _an_, without, [Greek: aisthesia], _aisthesia_, feeling).--Those medicinal agents which prevent the feeling of pain, such as chloroform, laughing-gas, etc. AN-I-MAL´CULE (L. _animal´culum_, a small animal). Applied to animals which can only be seen with the aid of the microscope. Animalculum (plural, animalcula) is used with the same meaning. A-OR´TA (Gr. [Greek: aorteomai], _aorteomai_, to be lifted up). The largest artery of the body, and main trunk of all the arteries. It arises from the left ventricle of the heart. The name was first applied to the two large branches of the trachea, which appear to be lifted up by the heart. {253} A´QUE-OUS HUMOR (L. _aqua_, water). A few drops of watery colorless fluid occupying the space between the cornea and crystalline lens. A-RACH´NOID MEM´BRANE (Gr. [Greek: arachne], _arachne_, a cobweb, and [Greek: eidos], _eidos_, like). An extremely thin covering of the brain and spinal cord. It lies between the _dura mater_ and the _pia mater_. AR´BOR VI´TÆ (L.). Literally, "the tree of life;" a name given to the peculiar appearance presented by a section of the cerebellum. AR´TER-Y (Gr. [Greek: aer], _aer_, air, and [Greek: terein], _terein_, to contain). A vessel by which blood is conveyed away from the heart. It was supposed by the ancients to contain air; hence the name. AR-TIC-U-LA´TION (L. _articulo_, to form a joint). The more or less movable union of bones, etc.; a joint. A-RYT´E-NOID CAR´TI-LA-GES (Gr. [Greek: arutaina], _arutaina_, a pitcher). Two small cartilages of the larynx, resembling the mouth of a pitcher. AS-SIM-I-LA´TION (L. _ad_, to, and _similis_, like). The conversion of food into living tissue. AU-DI´TION (L. _audio_, to hear). The act of hearing sounds. AU´DI-TO-RY NERVE. One of the cranial nerves; it is the special nerve of hearing. AU´RI-CLE (L. _auris_, the ear). A cavity of the heart. BAR´I-TONE (Gr. [Greek: barus], _barus_, heavy, and [Greek: tonos], _tonos_, tone). A variety of male voice between the bass and tenor. BEL-LA-DON´NA (It. beautiful lady). A vegetable narcotic poison. It has the property of enlarging the pupil, and thus increasing the brilliancy of the eye; so called from its use by Italian ladies. BI-CUS´PID (L. _bi_, two, and _cuspis_, prominence). The name of the fourth and fifth teeth on each side of the jaw; possessing two prominences. BILE. The gall, or peculiar secretion of the liver; a viscid, yellowish fluid, and very bitter to the taste. BRONCH´I (Gr. [Greek: bronkos], _bronkos_, the windpipe). The two first divisions or branches of the trachea; one enters each lung. BRONCH´I-AL TUBES. The smaller branches of the trachea within the substance of the lungs, terminating in the air-cells. BRONCH-I´TIS (from _bronchia_, and _itis_, a suffix signifying inflammation). An inflammation of the larger bronchial tubes; a "cold" affecting the lungs. CAL-CA´RE-OUS (L. _calx_, lime). Containing lime. CA-NAL´ (L.). In the body, any tube or passage. CA-NINE´ (L. _canis_, a dog). Name given to the third tooth on each {254} side of the jaw; in the upper jaw it is also known as the eye-tooth: pointed like the tusks of a dog. CAP´IL-LA-RY (L. _capil´lus_, a hair, _capilla´ris_ hair-like). The name of the extremely minute blood-vessels which connect the arteries with the veins. CAR´BON DIOX-IDE (CO_{2}). Chemical name for carbonic acid gas. CAR-BON´IC A-CID. The gas which is present in the air expired from the lungs; a waste product of the animal kingdom, and a food of the vegetable kingdom. CAR´DI-AC (Gr. [Greek: kardia], _cardia_, the heart). The cardiac orifice of the stomach is the upper one, and is near the heart; hence its name. CAR-NIV´O-ROUS (L. _ca´ro_, flesh, and _vo´ro_, to devour). Subsisting upon flesh. CA-ROT´ID AR-TE-RY. The large artery of the neck, supplying the head and brain. CAR´TI-LAGE. A solid but flexible material, forming a part of the joints, air-passages, nostrils, etc.; gristle. CA´SE-INE (L. _ca´seus_, cheese). The albuminoid substance of milk; it forms the basis of cheese. CER-E-BEL´LUM (diminutive for _cer´ebrum_, the brain). The little brain, situated beneath the posterior third of the cerebrum. CER´E-BRUM (L.). The brain proper, occupying the entire upper portion of the skull. It is nearly divided into two equal parts, called "hemispheres," by a cleft extending from before backward. CHO´ROID (Gr. [Greek: chorion], _chorion_, a membrane or covering). The middle tunic or coat of the eyeball. CHYLE (Gr. [Greek: chulos], chulos, juice). The milk-like fluid formed by the digestion of fatty articles of food in the intestines. CHYME (Gr. [Greek: chumos], _chumos_, juice). The pulpy liquid formed by digestion within the stomach. CIL´I-A (pl. of _cil´i-um_, an eyelash). Minute, vibratile, hair-like processes found upon the cells of the air-passages, and other parts that are habitually moist. CIR-CU-LA´TION (L. _cir´culus_, a ring). The circuit, or course of the blood through the blood-vessels of the body, from the heart to the arteries, through the capillaries into the veins, and from the veins back to the heart. CO-AG-U-LA´TION (L. _coag´ulo_, to curdle). Applied to the process by which the blood clots or solidifies. COCH´LE-A (L. _coch´lea_, a snail-shell). The spiral cavity of the internal ear. {255} CONCH´A (Gr. [Greek: konchê], _konche_, a mussel-shell). The external shell-shaped portion of the external ear. CON-JUNC-TI´VA (L. _con_ and _jun´go_, to join together). A thin layer of mucous membrane which lines the eyelids and covers the front of the eyeball; thus joining the latter to the lids. CON-TRAC-TIL´I-TY (L. _con_ and _tra´ho_, to draw together). The property of a muscle which enables it to contract, or draw its extremities closer together. CON-VO-LU´TIONS (L. _con_ and _vol´vo_, to roll together). The tortuous foldings of the external surface of the brain. CON-VUL´SION (L. _convel´lo_, to pull together). A more or less violent agitation of the limbs or body. COR´NE-A (L. _cor´nu_, a horn). The transparent, horn-like substance which covers the anterior fifth of the eyeball. COR´PUS-CLES, BLOOD (L. dim. of _cor´pus_, a body). The small biconcave disks which give to the blood its red color; the _white_ corpuscles are globular and larger. COS-MET´IC (Gr. [Greek: kosmeô], _kosmeo_, to adorn). Beautifying; applied to articles which are supposed to increase the beauty of the skin, etc. CRA´NI-AL (L. _cra´nium_, the skull). Pertaining to the skull. The nerves which arise from the brain are called cranial nerves. CRI´COID (Gr. [Greek: krikos], _kri´kos_, a ring). A cartilage of the larynx, resembling a seal-ring in shape. CRYS´TAL-LINE LENS (L. _crystal´lum_, a crystal). One of the so-called humors of the eye; a double convex body situated in the front part of the eyeball. CU´TI-CLE (L. dim. of _cu´tis_, the skin). The scarf-skin; also called the _epider´mis_. CU´TIS (Gr. [Greek: skutos], _skutos_, a skin or hide). The true skin, lying beneath the cuticle; also called the _der´ma_. DE-CUS-SA´TION (L. _decus´sis_, the Roman numeral ten, X). A reciprocal crossing of fibres from side to side. DI´A-PHRAGM (Gr. [Greek: diaphrassô], _diaphrasso_, to divide by a partition). A large, thin muscle which separates the cavity of the chest from the abdomen; a muscle of respiration. DIF-FUS´ION OF GASES. The power of gases to become intimately mingled, without reference to the force of gravity. DUCT (L. _du´co_, to lead). A narrow tube; the _thoracic duct_ is the main trunk of the absorbent vessels. DU-O-DE´NUM (L. _duode´ni_, twelve). The first division of the small intestines, about twelve fingers-breadth long. {256} DU´RA MA´TER (L.). Literally, the hard mother; the tough membrane which envelops the brain. DYS-PEP´SI-A (Gr. [Greek: dus], _dus_, difficult, and [Greek: peptô], _pep´to_, to digest). Difficult or painful digestion; a disordered condition of the stomach. E-MUL´SION (L. _emul´geo_, to milk). Oil in a finely divided state suspended in water. EN-AM´EL (Fr. _email_). The dense material which covers the crown of the tooth. EN´ER-GY, Specific, of a Nerve. When a nerve of special sense is excited, whatever be the cause, the sensation experienced is that peculiar to the nerve; this is said to be the law of the specific energy of the nerves. EP-I-GLOT´TIS (Gr. [Greek: epi], _epi_, upon, and [Greek: glôttis], _glottis_, the entrance to the windpipe). A leaf-shaped piece of cartilage which covers the top of the larynx during the act of swallowing. EX-CRE´TION (L. _excer´no_, to separate). The separation from the blood of the waste particles of the body; also the materials excreted. EX-PI-RA´TION (L. _expi´ro_, to breathe out). The act of forcing air out of the lungs. EX-TEN´SION (L. _ex_, out, and _ten´do_, to stretch). The act of restoring a limb, etc., to its natural position after it has been flexed, or bent; the opposite of _Flexion_. FE-NES´TRA (L.). Literally, a window; the opening between the middle and internal ear. FI´BRIN (L. _fi´bra_, a fibre). An albuminoid substance found in the blood; in coagulating it assumes a fibrous form. FLEX´ION (L. _flec´to_, to bend). The act of bending a limb, etc. FOL´LI-CLE (L. dim. of _fol´lis_, a bag). A little pouch or depression in a membrane; it has generally a secretory function. FUN´GOUS GROWTHS (L. _fun´gus_, a mushroom). A low grade of vegetable life. GAN´GLI-ON (Gr. [Greek: ganglion], _ganglion_, a knot). A knot-like swelling in the course of a nerve; a smaller nerve-centre. GAS´TRIC (Gr. [Greek: gastêr], _gaster_, stomach). Pertaining to the stomach. GLAND (L. _glans_, an acorn). An organ consisting of follicles and ducts, with numerous blood-vessels interwoven; it separates some particular fluid from the blood. GLOS´SO-PHAR-YN-GE´AL NERVE (Gr. [Greek: glôssa], _glossa_, the tongue, and [Greek: pharunx], _pharunx_, the throat). The nerve of taste supplying the posterior third of the tongue; it also supplies the throat. GLU´TEN (L.). Literally, glue: the glutinous albuminoid ingredient of wheat. {257} GRAN´ULE (L. dim. of _gra´num_, a grain). A little grain; a microscopic object. GUS-TA´TION (L. _gus´to_, to taste) The sense of taste. GUS´TA-TO-RY NERVE. The nerve of taste supplying the front part of the tongue; a branch of the "fifth" pair. HÆM´OR-RHAGE (Gr. [Greek: haima], _hai´ma_, blood, and [Greek: rhêgnumi], _regnumi_, to burst). Bleeding, or the loss of blood. HEM-I-PLE´GIA (Gr. [Greek: hêmisus], _hemisus_, half, and [Greek: plêssô], _plesso_, to strike). Paralysis, or loss of power, affecting one side of the body. HEM´I-SPHERES (Gr. [Greek: sphaira], _sphaira_, a sphere). Half a sphere, the lateral halves of the cerebrum, or brain proper. HE-PAT´IC (Gr. [Greek: hêpar], _hepar_, the liver). Pertaining to the liver. HER-BIV´O-ROUS (L. _her´ba_, an herb, and _vo´ro_ to devour). Applied to animals that subsist upon vegetable food. HU´MOR (L.). Moisture: the humors are transparent contents of the eyeball. HY-DRO-PHO´BI-A (Gr. [Greek: hudor], _hudor_, water, and [Greek: phobeô], _phobeo_, to fear). A disease caused by the bite of a rabid dog or other animal. In a person affected with it, convulsions are occasioned by the sight of a glittering object, like water, by the sound of running water, and by almost any external impression. HY´GI-ENE (Gr. [Greek: hugieia], _huygieia_, health). The art of preserving health and preventing disease. HY´PER-O-PI-A. Abbreviated from HY´PER-MET-RO´PI-A (Gr. [Greek: huper], _huper_, beyond, [Greek: metron], _metron_, the measure, and [Greek: ôps], _ops_, the eye). A defect of vision dependent upon a too short eyeball; so called because the rays of light are brought to a focus at a point behind the retina; the true "far sight." IN-CI´SOR (L. _inci´do_, to cut). Applied to the four front teeth of both jaws, which have sharp cutting edges. IN´CUS (L). An anvil; the name of one of the bones of the middle ear. IN-SAL-I-VA´TION (L. _in_, and _sali´va_, the fluid of the mouth). The mingling of the saliva with the food during the act of chewing. IN-SPI-RA´TION (L. _in_, and _spi´ro_, _spira´tum_, to breathe). The act of drawing in the breath. IN-TEG´U-MENT (L. _in_, and _te´go_, to cover). The skin, or outer covering of the body. IN-TES´TINE (L. _in´tus_, within). The part of the alimentary canal which is continuous with the lower end of the stomach; also called the intestines, or the bowels. I´RIS (L. _i´ris_, the rainbow). The thin muscular ring which lies {258} between the cornea and crystalline lens, and which gives the eye its brown, blue, or other color. JU´GU-LAR (L. _ju´gulum_, the throat). The name of the large veins which run along the front of the neck. LAB´Y-RINTH (Gr. [Greek: laburinthos], _laburin´thos_, a building with many winding passages). The very tortuous cavity of the inner ear, comprising the vestibule, semicircular canals, and the cochlea. LACH´RY-MAL APPARATUS (L. _lach´ryma_, a tear). The organs for forming and conveying away the _tears_. LAC´TE-ALS (L. _lac_, _lac´tis_, milk). The absorbent vessels of the small intestines; during digestion they are filled with chyle, which has a milky appearance. LA-RYN´GO-SCOPE (Gr. [Greek: larunx], _larunx_, the larynx, and [Greek: skopeô], _skopeo_, to look at). The instrument by which the larynx may be examined in the living subject. LAR´YNX (Gr.). The cartilaginous tube situated at the top of the windpipe, or trachea; the organ of the voice. LENS (L.). Literally, a lentil; a piece of transparent glass or other substance so shaped as either to converge or disperse the rays of light. LIG´A-MENT (L. _li´go_, to bind). A strong, fibrous material binding bones or other solid parts together; it is especially necessary to give strength to joints. LIG´A-TURE. A thread of silk or other material used in tying around an artery. LYMPH (L. _lym´pha_, spring-water). The colorless, watery fluid conveyed by the lymphatic vessels. LYM-PHAT´IC VESSELS. A system of absorbent vessels. MAL´LE-US (L.). Literally, the mallet; one of the small bones of the middle ear. MAR´ROW. The soft, fatty substance contained in the central cavities of the bones: the spinal marrow, however, is composed of nervous tissue. MAS-TI-CA´TION (L. _mas´tico_, to chew). The act of cutting and grinding the food to pieces by means of the teeth. ME-DUL´LA OB-LON-GA´TA. The "oblong marrow," or nervous cord, which is continuous with the spinal cord within the skull. MEM-BRA´NA TYM´PAN-I (L.). Literally, the membrane of the drum; a delicate partition separating the outer from the middle ear; it is sometimes incorrectly called the drum of the ear. MEM´BRANE. A thin layer of tissue serving to cover some part of the body. MI´CRO-SCOPE (Gr. [Greek: mikros], _mikros_, small, and [Greek: skopeô], _skopeo_, to {259} look at). An optical instrument which assists in the examination of minute objects. MO´LAR (L. _mo´la_, a mill). The name applied to the three back teeth of each side of the jaw; the grinders, or mill-like teeth. MO´TOR (L. _mo´veo_, _mo´tum_, to move). Causing motion; the name of those nerves which conduct to the muscles the stimulus which causes them to contract. MU´COUS MEMBRANE. The thin layer of tissue which covers those internal cavities or passages which communicate with the external air. MU´CUS. The glairy fluid which is secreted by mucous membranes, and which serves to keep them in a moist condition. MY-O´PI-A (Gr. [Greek: muô], _muo_, to contract, and [Greek: ôps], _ops_, the eye). A defect of vision dependent upon an eyeball that is too long, rendering distant objects indistinct; near-sight. NA´SAL (L. _na´sus_, the nose). Pertaining to the nose; the _nasal cavities_ contain the distribution of the special nerve of smell. NERVE (Gr. [Greek: neuron], _neuron_, a cord or string). A glistening, white cord of cylindrical shape, connecting the brain or spinal cord with some other organ of the body. NERVE CELL. A minute, round and ashen-gray cell found in the brain and other nervous centres. NERVE FI´BRE. An exceedingly slender thread of nervous tissue found in the various nervous organs, but especially in the nerves; it is of a white color. NU-TRI´TION (L. _nu´trio_, to nourish). The processes by which the nourishment of the body is accomplished. OE-SOPH´A-GUS (Gr.). Literally, that which carries food. The tube leading from the throat to the stomach; the gullet. O-LE-AG´I-NOUS (L. _o´leum_, oil). Of the nature of oil: applied to an important group of food-principles--the fats. OL-FAC´TO-RY (L. _olfa´cio_, to smell). Pertaining to the sense of smell. OPH-THAL´MO-SCOPE (Gr. [Greek: ophthalmos], _ophthalmos_, the eye, and [Greek: skopeô], _skopeo_, to look at). An instrument devised for examining the interior of the globe of the eye. OP´TIC (Gr. [Greek: optô], _opto_, to see). Pertaining to the sense of sight. OR´BIT (L. _or´bis_, the socket). The bony socket or cavity in which the eyeball is situated. OS´MOSE (Gr. [Greek: ôsmos], _osmos_, a thrusting or impulsion). The process by which liquids are impelled through a moist membrane. OS´SE-OUS (L. _os_, a bone). Consisting of, or resembling bone. PAL´ATE (L. _pala´tum_, the palate). The roof of the mouth, consisting of the hard and soft palate. {260} PAL´MAR. Relating to the palm of the hand. PAN´CRE-AS (Gr. [Greek: pas], [Greek: pantos], _pas_, _pantos_, all, and [Greek: kreas], _kreas_, flesh). A long, flat gland situated near the stomach; in the lower animals the analogous organ is called the sweet-bread. PA-PIL´LÆ (L. _papil´la_). The minute prominences in which terminate the ultimate fibres of the nerves of touch and taste. PA-RAL´Y-SIS. A disease of the nervous system marked by the loss of sensation, or voluntary motion, or both; palsy. PAR-A-PLE´GI-A (Gr. [Greek: paraplêssô], _paraplesso_, to strike amiss). A form of paralysis affecting the lower half of the body. PA-TEL´LA (L. dim. of _pat´ina_, a pan). The knee-pan; a small bone. PEL´VIS (L.). Literally a basin; the bony cavity at the lower part of the trunk. PEP´SIN (Gr. [Greek: peptô], _pepto_, to digest). The organic principle of the gastric juice. PER-I-STAL´TIC MOVE´MENTS (Gr. [Greek: peristellô], _peristello_, to contract). The slow, wave-like movements of the stomach and intestines. PER-I-TO-NE´UM (Gr. [Greek: periteinô], _periteino_, to stretch around). The investing membrane of the stomach, intestines, and other abdominal organs. PER-SPI-RA´TION (L. _perspi´ro_, to breathe through). The sweat, or watery exhalation of the skin; when visible, it is called _sensible_ perspiration, when invisible, it is called _insensible_ perspiration. PE´TROUS (Gr. [Greek: petra], _petra_, a rock). The name of the hard portion of the temporal bone, in which is situated the drum of the ear and labyrinth. PHAR´YNX (Gr. [Greek: pharunx], _pharunx_, the throat). The cavity between the back of the mouth and gullet. PHYS-I-OL´O-GY (Gr. [Greek: phusis], _phusis_, nature, and [Greek: logos], _logos_, a discourse). The science of the functions of living, organized beings. PI´A MA´TER (L.). Literally, the tender mother; the innermost of the three coverings of the brain. It is thin and delicate; hence the name. PLEU´RA (Gr. [Greek: pleura], a rib). A membrane covering the lung and lining the chest. There is one for each lung. PLEU´RI-SY. An inflammation affecting the pleura. PNEU-MO-GAS´TRIC (Gr. [Greek: pneumôn], _pneumon_, the lungs, and [Greek: gastêr], _gaster_, the stomach). The name of a nerve distributed to the lungs and stomach; it is the principal nerve of respiration. PNEU-MO´NIA (Gr.). An inflammation affecting the air-cells of the lungs. {261} PRES-BY-O´PI-A (Gr. [Greek: presbus], _presbus_, old, and [Greek: ôps], _ops_, the eye). A defect of the accommodation of the eye, caused by the hardening of the crystalline lens; the "far-sight" of adults and aged persons. PROC´ESS (L. _proce´do_, _proces´sus_, to proceed, to go forth). Any projection from a surface. Also, a method of performance; a procedure. PTY´A-LIN (Gr. [Greek: ptualon], _ptualon_, saliva). The peculiar organic ingredient of the saliva. PUL´MO-NA-RY (L. _pul´mo_, _pulmo´nis_, the lungs). Pertaining to the lungs. PULSE (L. _pel´lo_, _pul´sum_, to beat). The striking of an artery against the finger, occasioned by the contraction of the heart, commonly felt at the wrist. PU´PIL (L. _pupil´la_). The central, round opening in the iris, through which light passes into the depths of the eye. PY-LO´RUS (Gr. [Greek: pulôros], _puloros_, a gate-keeper). The lower opening of the stomach, at the beginning of the small intestine. RE´FLEX ACTION. An involuntary action of the nervous system, by which an external impression conducted by a sensory nerve is reflected, or converted into a motor impulse. RES-PI-RA´TION (L. _res´piro_, to breathe frequently). The function of breathing, comprising two acts: _inspiration_, or breathing in, and _expiration_, or breathing out. RET´I-NA (L. _re´te_, a net). The innermost of the three tunics or coats of the eyeball, being an expansion of the optic nerve. SAC´CHA-RINE (L. _sac´charum_, sugar). Of the nature of sugar; applied to the important group of food substances which embraces the different varieties of sugar, starch, and gum. SA-LI´VA (L.). The moisture or fluids of the mouth, secreted by the salivary glands, etc. SCLE-ROT´IC (Gr. [Greek: sklêros], _skleros_, hard). The tough, fibrous outer tunic of the eyeball. SE-BA´CEOUS (L. _sebum_, fat). Resembling fat, the name of the oily secretion by which the skin is kept flexible and soft. SE-CRE´TION (L. _secer´no_, _secre´tum_, to separate). The process of separating from the blood some essential important fluid; which fluid is also called a secretion. SEM-I-CIR´CU-LAR CANALS. A portion of the internal ear. SEN-SA´TION. The perception of an external impression by the nervous system; a function of the brain. SEN-SI-BIL´I-TY, GENERAL. The power possessed by nearly all parts {262} of the human body of recognizing the presence of foreign objects that come in contact with them. SE´RUM (L.). The watery constituent of the blood, which separates from the clot during the process of coagulation. SKEL´E-TON (Gr.). The bony framework of an animal, the different parts of which are maintained in their proper relative positions. SPEC´TRO-SCOPE (from _spec´trum_ and [Greek: skopeô], _scopeo_, to examine the spectrum). An instrument employed in the examination of the spectrum of the sun or any other luminous body. SPHYG´MO-GRAPH (Gr. [Greek: sphugmos], _sphugmos_, the pulse, and [Greek: graphô], _grapho_, to write). An ingenious instrument by means of which the pulse is delineated upon paper. STA´PES (L.). Literally, a stirrup; one of the small bones of the tympanum, or middle ear, resembling somewhat a stirrup in shape. SYM-PA-THET´IC SYSTEM OF NERVES. A double chain of nervous ganglia, connected together by numerous small nerves, situated chiefly in front of and on each side of the spinal column. SYN-O´VI-A (Gr. [Greek: sun], _sun_, and [Greek: ôon], _oon_, resembling an egg). The lubricating fluid of joints, so called because it resembles the white of egg. SYS´TO-LE (Gr. [Greek: sustellô], _sustello_, to contract). The contraction of the heart, by which the blood is expelled from that organ. TAC´TILE (L. _tac´tus_, touch). Relating to the sense of touch. TEM´PO-RAL (L. _tem´pus_, time, and _tem´pora_, the temples). Pertaining to the temples; the name of an artery: so called, because the hair begins to turn white with age in that portion of the scalp. TEN´DON (L. _ten´do_, to stretch). The white, fibrous cord or band by which a muscle is attached to a bone; a sinew. TET´A-NUS (Gr. [Greek: teinô], _teino_, to stretch). A disease marked by persistent contractions of all or some of the voluntary muscles; those of the jaw are sometimes solely affected: the disorder is then termed locked-jaw. THO´RAX (Gr. [Greek: thôrax], _thorax_, a breastplate). The upper cavity of the trunk of the body, containing the lungs, heart, etc.; the chest. THY´ROID (Gr. [Greek: thureos], _thureos_, a shield). The largest of the cartilages of the larynx; its angular projection in the front of the neck is called "Adam's apple." TRA´CHE-A (Gr. [Greek: trachus], _trachus_, rough). The windpipe, or the largest of the air-passages; composed in part of cartilaginous rings, which render its surface rough and uneven. TRANS-FU´SION (L. _transfun´do_, to pour from one vessel to another). {263} The operation of injecting blood taken from one person into the veins of another; other fluids than blood are sometimes used. TRICH-I´NA SPI-RA´LIS. (L.) A minute species of parasite or worm, which infests the flesh of the hog, and which may be introduced into the human system by eating pork not thoroughly cooked. TYM´PA-NUM (Gr. [Greek: tumpanon], _tumpanon_, a drum). The cavity of the middle ear, resembling a drum in being closed by two membranes, and in having communication with the atmosphere. U´VU-LA (L. _uva_, a grape). The small pendulous body attached to the back part of the palate. VAS´CU-LAR (L. _vas´culum_, a little vessel). Pertaining to, or containing blood-vessels. VE´NOUS (L. _ve´na_, a vein). Pertaining to, or contained within a vein. VEN-TI-LA´TION. The introduction of fresh air into a room or building, in such a manner as to keep the air within it in a pure condition. VEN-TRIL´O-QUISM (L. _ven´ter_, the belly, and _lo´quor_, to speak). A modification of natural speech by which the voice is made to appear to come from a distance. The ancients supposed that the voice was formed in the belly; hence the name. VEN´TRI-CLES of the heart. The two largest cavities of the heart, situated at its apex or point. VER´TE-BRAL COLUMN (L. _ver´tebra_, a joint). The back-bone, consisting of twenty-four separate bones, called vertebræ, firmly jointed together; also called the spinal column and spine. VES´TI-BULE. A portion of the internal ear, communicating with the semicircular canals and the cochlea; so called from its fancied resemblance to the vestibule or porch of a house. VIL´LI (L. _vil´lus_, the nap of cloth). Minute thread-like projections found upon the internal surface of the small intestine, giving it a velvety appearance. VIT´RE-OUS (L. _vi´trum_, glass). Having the appearance of glass; applied to the humor occupying the largest part of the cavity of the eyeball. VIV-I-SEC´TION (L. _vi´vus_, alive, and _se´co_, to cut). The practice of operating upon living animals, for the purpose of studying some physiological process. VOCAL CORDS. Two elastic bands or ridges situated in the larynx; they are the essential parts of the organs of the voice. * * * * * {265} INDEX. ------o------ A. PAGE Absorbent vessels, 97 Absorption, 96 by blood-vessels, 96 by the lacteals, 96 of the food, 96 Accommodation, function of, 213 Achilles, tendon of, 27 Adam's apple, 229 Air, atmospheric, 131 Changes in, in respiration, 132 Carbonic acid in, 138 Composition of, 131 Dust in the, 137 Effects of impure, 139 Impurities in, 136 Matters in the expired, 132 Provision for purifying, 141 Renovation by ventilation, 142 Air-cells of the lungs, 125 Air-passages, 125 Albinos, 44 Albumen, 58 of the blood, 102 Albuminoid substance, 57 Varieties of, 57 Properties of, 57-58 Albuminose, 94 Alcoholic liquors, 77 Physiological action of, 78 Alimentary canal, 81 Animal functions, 143 Animal heat, 143 how produced, 143 regulated by perspiration, 145 Animals, relative strength of, 28 Apoplexy, 171 Aqueous humor, 210 Arachnoid membrane, 152 Arbor vitæ, 154 Arterial blood, 107-135 differs from venous, 135 Arteries, 114 Arrangement of, 115 Carotid, 116 Distribution of, 115 Pulsation of, 115 Radial, 116 Temporal, 116 Arytenoid cartilage, 229 Asphyxia, 250 Assimilation, 80, 121 Audition, 215 Auditory canal, 218 nerve, 222 Auricles of the heart, 109 B. Back-bone, 21 Bathing, 47 Importance of, 47 Time and manner of, 49 Baths, 48 Different kinds of, 48 Belladonna, 206 dilates the pupil, 206 Use as a cosmetic, 206 Bile, 95 Secretion of, in the liver, 95 Accumulation of, in the gall-bladder, 95 Uses of, 95 Biliary duct, 95 Bladder, Gall-, 95 Bleeding, how stopped, 121 Blind-spot, 207 Blood, 101 Arterial, 107-135 Change of color, 107 Circulation of, 107, 133 Coagulation of, 105 Composition of, 102 corpuscles, 102, 103 fluid, 105 Microscopic appearance of, 102 Respiratory changes in, 133 Uses of the, 105 Venous, 107, 135 Blood-vessels, 114, 118 Absorption by, 96 Injuries to the, 121 Body, renovation of the, 66 Bones, 15 Form and composition of, 16 Growth of, 22 Microscopic structure of, 17 Repair of, 23 Structure of, 17 Uses of, 15 Bowels, 94 Brain, 150 Anatomical structure of, 152 Function of the, 172 Injuries of the, 173 Membranes of the, 152 Reflex action of the, 174 {266} Bread, 72 Bronchial tubes, 125 Bronchitis, 128 C. Canals, Semicircular, 223 Capillary blood-vessels, 118 Circulation in the, 118 Carbonic acid, 132 exhaled from the lungs, 132 in the air, 138 retention in the blood, 134 Cartilage, 20 Arytenoid, 229 Cricoid, 229 Thyroid, 229 Casein, 58 Cataract, 210 Cells, Nerve, 150, 159 Ciliated, 128 Cerebellum, 153 Function of the, 172 Cerebro-spinal nervous system, 150 Cerebrum, 152 Function of the, 172 Cheese, 58 Chest, Framework of, 19 Contents of the, 19 Chocolate, 77 Chorea, 169 Choroid coat of the eye, 204 Chyle, 95 Chyme, 94 Cilia, 128 Circulation, 107 in the frog's foot, 119 of the blood, 107 Rapidity of, 120 through the heart, 112 through the lungs, 123 Clothing, 51 Coagulation of milk, 58 of the blood, 104 Cochlea, 223 Coffee, 75 Effects of, 75, 76 Collar-bone, 19 Color-blindness, 209 Column, Spinal, 21 Combustion, Spontaneous, 145 Complexion, 44 Concha of the ear, 217 Conjunctiva, 200 Contraction of heart, 111 of muscles, 27 Convulsions, 169 Cooking, 70 Cords, Vocal, 126, 230 Cornea, 203 Corpuscles, Blood, 102 Cosmetics, 51 Cranial ganglia, 150 Functions of, 171 Cranial nerves, 154 Cranium, 19 Cricoid cartilage, 229 Crystalline lens, 209 Uses of, 210 Cuticle, 41 Function of, 183 Cutis, 42 D. Decussation of motor and sensory fibres of spinal cord, 164 Dentition of infancy, 82 Diaphragm, Movements of the, in respiration, 128, 129 Diastole of the heart, 111 Diet, Mixed, 66, 85 Necessity for changing, 67 Necessity of a regulated, 62 The best, 63 Digestion, 80 Circumstances affecting, 97 Gastric, 93 Intestinal, 94 Nature of, 81 Organs of, 81-91 Drowning, 250 Duct, Biliary, 95 Nasal, 201 Pancreatic, 95 Thoracic, 97 Dura Mater, 152 E. Ear, 217 External, 217 Internal, 222 Middle, 219 Foreign bodies in, 225 Drum of the, 219 Bones of the, 220 Ear-sand, 223 Ear-stones, 223 Ear-wax, 219 Eggs, 68 Composition of, 68 Emulsion of fats, in digestion, 95 Enamel of the teeth, 82 Epiglottis, 126, 229 Uses of, 126, 220 Eustachian tube, 221 Exercise, 30 Different modes of, 31 Effects of, 30 Importance of, 30 Open-air, 33 Expiration, 128 Movements of, 129 Extensor muscles, 26 Eye, 198 Eyeball, 203 Eyelashes, 200 Eyelids, 200 F. Fats, 59 Emulsion of, 59 Source of, in food, 59 Fenestra ovalis, 224 Fibres, Muscular, 25 {267} Fibres, Nervous, 149 Fibrine in food, 58 of the blood, 102 Fish, as food, 71 Flexor muscles, 26 Food, 53 Animal, 67 Daily quantity of, 65 Ingredients of, 54-62 Necessity for, 64 Source of, 53 Vegetable, 71 G. Gall-bladder, 95 Ganglia, cranial, Functions of the, 171 Gases, Interchange of, in the lungs, 134 Gastric digestion, 93 Gastric juice, 91 Action of, 93 Daily quantity of, 92 General sensibility, 179 Glands, Perspiratory, 45 Salivary, 86 Sebaceous, 44 Glossary, 252 Glosso-pharyngeal nerve, 189 Gullet, 90 Gum, 61 as food, 62 Gustatory nerve, 189 Gymnastics, 33-38 for schools and colleges, 33 H. Hair, 42 Uses of, 44 Hearing, Sense of, 215 Protection of, 224 Heart, 107 Cavities of the, 109, 110 Circulation through the, 112 Frequency of action, 112 Movements of the, 111 Valves of the, 112 Heat, Animal, 143 Production of, 143 Regulation of, 145 Hemiplegia, 165 Humor, Aqueous, 210 Crystalline, 209 Vitreous, 210 Hunger, 65 Seat of the sensation of, 65 Hydra, 149 Hydrophobia, 169 Hygiene, 13 Hyperopia, 212 I. Incus, 220 Inorganic substances in food, 54 Insalivation, 86, 88 Insensible perspiration, 46 Inspiration, 128 Intestinal juice, 95 Action of, 96 Intestines, 94 Complete digestion in the small, 94 Villi of the, 96 Iris, 205 Function of, 205 Iron, 56 Proportion in the blood, 57 Proportion in the food, 57 J. Joints, 19 Varieties of, 20 Juice, gastric, 91 Intestinal, 95 Pancreatic, 95 L. Labyrinth, 222 Lachrymal canals, 201 gland, 201 Lacteals, 96 Absorption by, 96 Lactic acid in gastric juice, 92 Lactometer, 68 Large intestines, 94 Laryngoscope, 231 Larynx, 125, 228 Production of the voice in the, 126, 228 Lens, crystalline, 209 Ligaments, 19 Light, theory of, 197 Lime in the bones, 16 in the food, 56 Importance of, 56 Liver, 95 Secretion of the, 95 Locked jaw, 169 Long-sight, 212 Lungs, 123 Capacity of, 130 Structure of, 125 Lymph, 97 Lymphatic vessels, 97 M. Magendie, on pain, 181 Magnesia, Compounds of, in food, 57 Malleus, 220 Marrow of the bones, 17 Mastication, 82 Importance of, 88, 89 Meats, 68 The cooking of, 69 The preservation of, 69 Membrane of the tympanum, 219 Medulla oblongata, 154 Function of the, 171 Microscope, 236 The value of the, 236 Simple, 237 Compound, 239 The use of the, 239 {268} Milk, 68 Composition of, 68 Specific gravity of, 68 Milk-teeth, 82 Mucous membrane of air passages, 127 Muscles, 25 Function of the, 25 Flexion and extension of, 26 Voluntary and involuntary, 26 Muscular contraction, 27 fibres, 25 sense, 188 Myopia 212 N. Nails, 42 Uses of the, 44 Nasal cavities, 192 duct, 201 Nerve, Auditory, 222 Glossopharyngeal, 189 Gustatory, 189 Olfactory, 193 Optic, 197 Sympathetic, 158 Nerve cells, 150, 159 Nerve fibres, 149 Nerves, Cranial, 154 Spinal, 156 Functions of the, 160 Sensory, functions of the, 160 Motor, functions of the, 160 Sympathetic system of, 158 Nervous system, 148, 149 Cerebro-spinal, 150 Nervous tissue, Properties of, 159 Nose, 192 Nutrition, Processes of, 80 O. Oesophagus, 90 Oil, Sources of, in food, 59 Old-sight, 215 Olfactory nerve, 193 Optic nerve, 197 Orbicular bone, 220 Orbit of the eye, 199 Organic substances as food, 57-62 Organs of circulation, 107 Digestion, 81-91 Respiration, 123 Sight, 198 Voice, 228 Oxygen, 131 Amount of, consumed in respiration, 132 Continually supplied to the atmosphere, 141 P. Pain, Relations of, to pleasure, 181 Sensation of, 180 Uses of, 180 Pancreatic juice, 95 Uses of, 95 Pancreatin, 95 Paraplegia, 163 Parlor gymnasium, 36 Passages, Air, 125 Pelvis, 19 Pepsin, 92 Peristaltic action of the stomach, 92 Peritoneum, 94 Perspiration, Daily amount of, 46 Sensible and insensible, 46 Uses of, 46, 145 Perspiratory glands, 45 Physical strength, 29 Culture, 33 Physiology, 11 Animal, 11 Comparative, 11 Human, 11 Vegetable, 11 Pia mater, 152 Plasma of the blood, 102 Pleura, 124 Pleurisy, 128 Pneumo gastric nerve, 171 Pneumonia, 128 Poisons and their antidotes, 247 Potash in the blood, 57 Potato, 73 Presbyopia, 215 Preservation of the teeth, 85 Ptyalin, 88 Pulsation of the heart, 113 of the arteries, 116 Pulse, 115 Form of the, 116 Writer, 116 Pylorus, 90 R. Radial artery, 116 Red corpuscles of the blood, 102 Reflex action of the spinal cord, 165 Requisites for, 167 Uses of, 167, 170 Causing convulsions, 169 Objects of, 170 of the brain, 174, 175 Rennet, 58 Respiration, 123 Change of blood in, 123-133 Frequency of, 129 Movements of, 128 Object of, 123 Organs of, 123 Respiratory labor, 135 Rest, necessity for, 38 Retina, 206 Retinal light, 207 Ribs, Movements of, in respiration, 128 S. Saccharine substances, 60 Saliva, 86 Importance of, 88 Secretion of, 86 Salivary glands, 86, 87 {269} Salt, Common, 55 Importance of, 56 Sclerotic coat of the eyeball, 204 Sebaceous glands, 44 Secretion of, 45 Semicircular canals, 223 Sensation of pain, 180 Relations of, to pleasure, 181 of temperature, 187 of weight, 188 Modification of, 178 Production of, 177 Variety of, 178 Sense of hearing, 215 sight, 196 smell, 192 taste, 189 touch, 184 Sense, muscular, 188 thermal, 187 Senses, Special, 177 Sensibility, General, 179 Short-sight, 212 Sinews, 27 Sight, Sense of, 196 Organs of, 198 Skeleton, 19 Skin, 41 Structure of, 41 Skull, 19 Uses of the, 19 Sleep, Necessity for, 38 Amount required, 39 Small intestines, 94 Smell, Sense of, 192 Nerve of, 193 Uses of, 194 Soda in the food, 57 Sound, Production of, 215 Special senses, 177 Spectroscope, 104 Speech, 227 Relation of, to the sense of hearing, 228 Sphygmograph, 116 Spinal column, 21 Spinal cord, 155 Decussation of the, 164 Direction of fibres in, 164 Functions of the, 162 Nerves of, 156 Reflex action of, 165 Spontaneous combustion, 145 Stapes, 220 Starch, 61 Its change into sugar, 61 Different kinds, 61 Effect of boiling, 61 Microscopic appearance, 61 Stimulating substances, 62 Stomach, 90, 92 Digestion, 93 Movements of, 92 Secretion of, 92 St. Vitus' dance, 169 Sugar, 60 Varieties, 60 Sources of, 61 Sun-bath, 50 Sympathetic system of nerves, 158 Synovia, 20 Systole of the heart, 111 T. Taste, Association of, 190 Education of, 191 Organ of, 188 Sense of, 189 Tea, Effect of, 76 Kinds of, 76 Tears, 201 Escape of the, 201 Teeth, 82 Temporary set of, 82 Permanent set of, 83 Bicuspid, 83 Canine, 83 Incisor, 83 Molar, 84 Arrangement of, 85 of different animals, 85 Preservation of, 85 Temperature of the body, 146 Extremes of, 146 Sensations of, 187 Tendon of Achilles, 27 Tendons, 27 Tetanus, 169 Thermal, 50 Thermæ sense, 187 Thirst, 65 Thoracic duct, 97 Thorax, 19 Thyroid cartilage, 229 Tissues, intimate structure of the, 236 Human, 244 of the lower animals, 245 Tongue, 188 Nerves of, 189 Sensibility, 189 Touch, Delicacy of, 186 Organs of, 183 Sense of, 184 Trachea, 125 Transfusion, 106 Trichina spiralis, 71 Trunk, 19 Tympanum of the ear, 219 Membrane of, 219 V. Valves of the heart, 112 of the veins, 117 Vapor, Animal, in breath, 132 Vegetable food, 71 Vegetative functions, 148 Veins, 117 Valves of, 117 Venous blood, 135 Changes of, in respiration, 133 Ventilation, 142 Ventricles of the larynx, 229 of the heart, 110 Ventriloquism, 235 {270} Vertebrae, 21 Vestibule of the internal ear, 223 Villi of the intestines, 96 Absorption by, 96 Vital knot, 171 Vitreous humor, 210 Vocal cords, 126, 230 Observation of, with laryngoscope, 231 Voice, 227 Organ of, 228 Production of, 232 Varieties of, 233 W. Water, 74 Action of, on lead, 75 Chemically pure, 74 Croton, 74 exhaled with the breath, 132 from springs and wells, 74 Proportion of, in the blood 55 " of, in the tissues and fluids of the body, 54 Ridgewood, 74 Walking, as a means of exercise, 31 White corpuscles of the blood, 104 Wisdom teeth, 84 * * * * * Changes made to printed original Page 45, Sect. 12. "(4, Fig. 14)": '(4, Fig. 13)' in original. Page 20, Sect. 20, note. "philosophy": 'philosphy' in original. Page 101, heading. "Sphygmograph": 'Spygmograph' in original. So also in Table of Contents, but cf. p. 116 and Index. Page 144, Sect. 46, note. "zoologists": 'zooligsts' in original. Page 199, Sect. 53. "considerable": 'considera-ale' (on line break) in original. Page 255, s.v. Convolutions. "external": 'extenal' in original. 
42660	----	Transcriber's note: Minor spelling and punctuation inconsistencies been harmonized. Obvious printer errors have been repaired. Italic text has been marked with _underscores_. Please see the end of this book for further notes. EXPERIMENTS ON ANIMALS [Illustration: BRAIN OF AN ANTHROPOID APE, SHOWING THE POSITION OF THE MOTOR CENTRES. (From a paper by Sir Victor Horsley and Dr. Beevor. _Phil. Trans. Roy. Soc._, 1892.)] EXPERIMENTS ON ANIMALS BY STEPHEN PAGET WITH AN INTRODUCTION BY LORD LISTER THIRD AND REVISED EDITION "_Perhaps it is wrong to compare sin with sin, but I declare to you, the more I think of it, the more intimately does this Prejudice seem to me to corrupt the soul, even beyond those sins which are commonly called more deadly._"--CARDINAL NEWMAN. NEW YORK WILLIAM WOOD AND COMPANY MDCCCCVII TO CHARLES ALFRED BALLANCE M.S., F.R.C.S. AND WILLIAM HUNTER M.D., F.R.C.P. PREFACE The first edition of this book was published in 1900. For twelve years it had been my business, as Secretary to the Association for the Advancement of Medicine by Research, to know something about experiments on animals, and to follow the working of the Act of 1876; and to give facts and references to a very large number of applicants. Believing that an account of these experiments, and of the conditions imposed on them by the Act, might serve a useful purpose, I proposed to the Council of the Association that I should write a book on the subject. The Council accepted this proposal; and decided that the book should be written for general reading, that it should not be anonymous, and that it should be published without reserve. It was, of course, a doubtful and embarrassing task. But, from twelve years' experience of the things said by the chief opponents of all experiments on animals, I knew that there was only one way of doing it--to give the original authorities, the plain facts, the very words, chapter and verse for everything. Among those who kindly revised the proofs were Prof. Rose Bradford and Prof. Starling, who revised Part I.; Mr. Shattock, who revised Part II.; and Prof. Schäfer. Valuable help was given by Mr. R. H. Clarke, Sir Victor Horsley, Dr. Beevor, Prof. Ronald Ross, and the late Dr. Washbourn; and I was allowed to make free use of Mr. George Pernet's careful researches into the history of the subject. Lord Lister himself did me the honour to read and correct, with the utmost patience, Parts I. and II. In the second edition (1904) some mistakes were corrected, and some facts were added. The present edition has been thoroughly revised; and I have included in it a reprint, with some changes and omissions, of a pamphlet, _The Case against Anti-vivisection_, which I wrote in 1904. 1906. INTRODUCTION TO THE FIRST EDITION This work by Mr. Paget is entirely a labour of love. Not being himself engaged in researches involving experiments upon the lower animals, he is not directly interested in the subject. But, in his official capacity as Secretary (1887-1899) to the Association for the Advancement of Medicine by Research, he has become widely conversant with such investigations, and has been deeply impressed with the greatness of the benefits which they have conferred upon mankind, and the grievous mistake that is made by those who desire to suppress them. The action of these well-meaning persons is based upon ignorance. They allow that man is permitted to inflict pain upon the lower animals when some substantial advantage is to be gained; but they deny that any good has ever resulted from the researches which they condemn. How far such statements are from the truth will be evident to those who peruse this book. Its earlier pages deal with Physiology, the main basis of all sound medicine and surgery. The examples given in this department are not numerous; they are, however, sufficiently striking, as indications that, from the discovery of the circulation of the blood onwards, our knowledge of healthy animal function has been mainly derived from experiments on animals. The chief bulk of the work is devoted to the class of investigations which are most frequent at the present day; and it shows what a flood of light has been already thrown by Bacteriology upon the nature of human disease and the means of combating it. The chapter on the Action of Drugs will be to many a startling disclosure of the gross ignorance that prevailed among physicians even in the earlier part of last century. The great revolution that has since taken place is no doubt largely due to advances in sciences other than Biology, especially Chemistry. But it could not have attained its present proportions without the ever-increasing knowledge of Physiology, based on experiments on animals; and Mr. Paget shows how large a share these have had in the direct investigation of articles of the Materia Medica. The concluding part of the volume discusses the restrictions which have been placed by the legislature in this country on those engaged in these researches, with the view of obviating possible abuse. Whether the Act in question has been really useful, whether it has not done more harm than good, by hampering and sometimes entirely preventing legitimate and beneficent investigation, I will not now discuss. Meanwhile I commend Mr. Paget's book to the careful consideration of the reader. LISTER. CONTENTS PART I EXPERIMENTS IN PHYSIOLOGY PAGE I. THE BLOOD 3 II. THE LACTEALS 19 III. THE GASTRIC JUICE 24 IV. GLYCOGEN 30 V. THE PANCREAS 36 VI. THE GROWTH OF BONE 40 VII. THE NERVOUS SYSTEM 44 PART II EXPERIMENTS IN PATHOLOGY, MATERIA MEDICA, AND THERAPEUTICS I. INFLAMMATION, SUPPURATION, AND BLOOD-POISONING 75 II. ANTHRAX 87 III. TUBERCLE 96 IV. DIPHTHERIA 102 V. TETANUS 128 VI. RABIES 137 VII. CHOLERA 152 VIII. PLAGUE 168 IX. TYPHOID FEVER; MALTA FEVER 196 X. THE MOSQUITO: MALARIA, YELLOW FEVER, FILARIASIS 214 XI. PARASITIC DISEASES 243 XII. MYXOEDEMA 247 XIII. THE ACTION OF DRUGS 251 XIV. SNAKE-VENOM 259 PART III THE ACT RELATING TO EXPERIMENTS ON ANIMALS IN GREAT BRITAIN AND IRELAND I. TEXT OF THE ACT 271 II. ANÆSTHETICS UNDER THE ACT 281 III. INSPECTORS' REPORT, 1905 283 PART IV THE CASE AGAINST ANTI-VIVISECTION I. ANTI-VIVISECTION SOCIETIES 297 II. LITERATURE 313 III. ARGUMENTS 325 IV. "OUR CAUSE IN PARLIAMENT" 367 V. A HISTORICAL PARALLEL 371 INDEX 377 PART I EXPERIMENTS IN PHYSIOLOGY EXPERIMENTS ON ANIMALS I THE BLOOD I.--BEFORE HARVEY Galen, born at Pergamos, 131 A.D., proved by experiments on animals that the brain is as warm as the heart, against the Aristotelian doctrine that the office of the brain is to keep the heart cool. He also proved that the arteries during life contain blood, not [Greek: pneuma], or the breath of life:-- "Ourselves, having tied the exposed arteries above and below, opened them between the ligatures, and showed that they were indeed full of blood." Though all vessels bleed when they are wounded, yet this experiment was necessary to refute the fanciful teaching of Erasistratus and his followers, of whom Galen says:-- "Erasistratus is pleased to believe that an artery is a vessel containing the breath of life, and a vein is a vessel containing blood; and that the vessels, dividing again and again, come at last to be so small that they can close their ultimate pores, and keep the blood controlled within them; yea, though the pores of the vein and of the artery lie side by side, yet the blood remains within its proper bounds, nowhere passing into the vessels of the breath of life. But when the blood is driven with violence from the veins into the arteries, forthwith there is disease; and the blood is poured the wrong way into the arteries, and there withstands and dashes itself against the breath of life coming from the heart, and turns the course of it--and this forsooth is fever." For many centuries after Galen, men were content to worship his name and his doctrines, and forsook his method. They did not follow the way of experiment, and invented theories that were no help either in science or in practice. Here, in Galen's observation of living arteries, was a great opportunity for physiology; but the example that he set to those who came after him was forgotten by them, and, from the time of Galen to the time of the Renaissance, physiology remained almost where he had left it. Of the men of the Renaissance, Servetus, Cæsalpinus, Ruinius, and others, Harvey's near predecessors, this much only need be said here, that they did not discover the circulation of the blood; and that the claim made a few years ago to this discovery, on behalf of Cæsalpinus, by his countrymen, was not successful. But it is probable that Realdus (1516-1557) did understand the passage of blood through the lungs, but not the general circulation. He says:-- "The blood is carried through the pulmonary artery to the lung, and there is attenuated; thence, mixed with air, it is carried through the pulmonary vein to the left ventricle of the heart: which thing no man hitherto has noted or left on record, though it is most worthy of the observation of all men.... And this is as true as truth itself; for if you will look, not only in the dead body but also in the living animal, you will always find this pulmonary vein full of blood, which assuredly it would not be if it were designed only for air and vapours.... Verily, I pray you, O candid reader, studious of authority, but more studious of truth, to make experiment on animals. You will find the pulmonary vein full of blood, not air or _fuligo_, as these men call it, God help them. Only there is no pulsation in the vein." (_De Re Anatomicâ_, Venice, 1559.) Fabricius ab Aquapendente, Harvey's master at Padua, published his work on the valves of the veins--_De Venarum Ostiolis_--in 1603. He did not discover them. Sylvius speaks of them in his _Isagoge_ (Venice, 1555), and they were known to Amatus (1552), and even to Theodoretus, Bishop of Syria, who lived, as John Hunter said of Sennertus, "the Lord knows how long ago." But Fabricius studied them most carefully; and in anatomy he left nothing more to be said about them. In physiology, his work was of little value; for he held that they were designed "to retard the blood in some measure, lest it should run pell-mell into the feet, hands, and fingers, there to be impacted": they were to prevent distension of the veins, and to ensure the due nourishment of all parts of the body. It is true that he compared them to the locks or weirs of a river, but he understood neither the course nor the force of the blood: as Harvey said of him, "The man who discovered these valves did not understand their right use; neither did they who came after him"--_Harum valvularum usum rectum inventor non est assecutus, nec alii addiderunt; non est enim ne pondere deorsum sanguis in inferiora totus ruat; sunt namque in jugularibus deorsum spectantes, et sanguinem sursum ferri prohibentes._ Men had no idea of the rapidity and volume of the circulation; they thought of a sort of Stygian tide, oozing this way or that way in the vessels--Cæsalpinus was of opinion that it went one way in the daytime and another at night--nor did they see that the pulmonary circulation and the general circulation are one system, the same blood covering the whole course. The work that they did in anatomy was magnificent; Vesalius, and the other great anatomists of his time, are unsurpassed. But physiology had been hindered for ages by fantastic imaginings, and the facts of the circulation of the blood were almost as far from their interpretation in the sixteenth century as they had been in the time of Galen. II.--HARVEY (1578-1657) The _De Motu Cordis et Sanguinis in Animalibus_ was published at Frankfurt in 1628. And it begins with these words: _Cum multis vivorum dissectionibus, uti ad manum dabantur_:-- "When by many dissections of living animals, as they came to hand, I first gave myself to observing how I might discover with my own eyes, and not from books and the writings of other men, the use and purpose of the movement of the heart in animals, forthwith I found the matter hard indeed, and full of difficulty: so that I began to think, with Frascatorius, that the movement of the heart was known to God alone. For I could not distinguish aright either the nature of its systole and diastole, or when or where dilatation and contraction took place; and this because of the swiftness of the movement, which in many animals in the twinkling of an eye, like a flash of lightning, revealed itself to sight and then was gone; so that I came to believe that I saw systole and diastole now this way now the other, and movements now apart and now together. Wherefore my mind wavered; I had nothing assured to me, whether decided by me or taken from other men: and I did not wonder that Andreas Laurentius had written that the movement of the heart was what the ebb and flow of the Euripus had been to Aristotle. "At last, having daily used greater disquisition and diligence, by frequent examination of many and various living animals--_multa frequenter et varia animalia viva introspiciendo_--and many observations put together, I came to believe that I had succeeded, and had escaped and got out of this labyrinth, and therewith had discovered what I desired, the movement and use of the heart and the arteries. And from that time, not only to my friends, but also in public in my anatomical lectures, after the manner of the Academy, I did not fear to set forth my opinion in this matter." It is plain, from Harvey's own words, that he gives to experiments on animals a foremost place among his methods of work. Take only the headings of his first four chapters:-- i. _Causæ, quibus ad scribendum auctor permotus fuerit._ ii. _Ex vivorum dissectione, qualis fit cordis motus._ iii. _Arteriarum motus qualis, ex vivorum dissectione._ iv. _Motus cordis et auricularum qualis, ex vivorum dissectione._ He thrusts it on us, he puts it in the foreground. Read the end of his Preface:-- "Therefore, from these and many more things of the kind, it is plain (since what has been said by men before me, of the movement and use of the heart and arteries, appears inconsistent or obscure or impossible when one carefully considers it) that we shall do well to look deeper into the matter; to observe the movements of the arteries and the heart, not only in man, but in all animals that have hearts; and by frequent dissection of living animals, and much use of our own eyes, to discern and investigate the truth--_vivorum dissectione frequenti, multâque autopsiâ, veritatem discernere et investigare_." Finally, take the famous passage in the eighth chapter, _De copiâ sanguinis transeuntis per cor e venis in arterias, et de circulari motu sanguinis_:-- "And now, as for the great quantity and forward movement of this blood on its way, when I shall have said what things remain to be said--though they are well worth considering, yet they are so new and strange that I not only fear harm from the envy of certain men, but am afraid lest I make all men my enemies; so does custom, or a doctrine once imbibed and fixed down by deep roots, like second nature, hold good among all men, and reverence for antiquity constrains them. Be that as it may, the die is cast now: my hope is in the love of truth, and the candour of learned minds. I bethought me how great was the quantity of this blood. Both from the dissection of living animals for the sake of experiment, with opening of the arteries, with observations manifold; and from the symmetry of the size of the ventricles, and of the vessels entering and leaving the heart--because Nature, doing nothing in vain, cannot in vain have given such size to these vessels above the rest--and from the harmonious and happy device of the valves and fibres, and all other fabric of the heart; and from many other things--when I had again and again carefully considered it all, and had turned it over in my mind many times--I mean the great quantity of the blood passing through, and the swiftness of its passage--and I did not see how the juices of the food in the stomach could help the veins from being emptied and drained dry, and the arteries contrariwise from being ruptured by the excessive flow of blood into them, unless blood were always getting round from the arteries into the veins, and so back to the right ventricle--I began to think to myself whether the blood had a certain movement, as in a circle--_coepi egomet mecum cogitare, an motionem quandam quasi in circulo haberet_--which afterward I found was true." This vehement passage, which goes with a rush like that of the blood itself, is a good example of the width and depth of Harvey's work--how he used all methods that were open to him. He lived to fourscore years; "an old man," he says, "far advanced in years, and occupied with other cares": and, near the end of his life, he told the Hon. Robert Boyle that the arrangement of the valves of the veins had given him his first idea of the circulation of the blood:-- "I remember that when I asked our famous Harvey, in the only discourse I had with him, which was but a while before he died, what were the things which induced him to think of the circulation of the blood, he answered me that when he took notice that the valves in the veins of so many parts of the body were so placed that they gave free passage of the blood towards the heart, but opposed the passage of the venal blood the contrary way, he was invited to imagine that so provident a cause as Nature had not so placed so many valves without design; and no design seemed more probable than that, since the blood could not well, because of the interposing valves, be sent by the veins to the limbs, it should be sent by the arteries, and return through the veins, whose valves did not oppose its course that way." But between this observation, which "invited him to imagine" a theory, and his final proofs of the circulation, lay a host of difficulties; and it is certain, from his own account of his work, that experiments on animals were of the utmost help to him in leading him "out of the labyrinth." III.--AFTER HARVEY 1. _The Capillaries_ The capillary vessels were not known in Harvey's time: the _capillamenta_ of Cæsalpinus were not the capillaries, but the [Greek: neura] of Aristotle. It was believed that the blood, between the smallest arteries and the smallest veins, made its way through "blind porosities" in the tissues, as water percolates through earth or through a sponge. The first account of the capillaries is in two letters (_De Pulmonibus_, 1661) from Malpighi, professor of medicine at Bologna, to Borelli, professor of mathematics at Pisa. In his first letter, Malpighi writes that he has tried in vain, by injecting the dead body, to discover how the blood passes from the arteries into the veins:-- "This enigma hitherto distracts my mind, though for its solution I have made many and many attempts, all in vain, with air and various coloured fluids. Having injected ink with a syringe into the pulmonary artery, I have again and again seen it escape (become extravasated into the tissues) at several points. The same thing happens with an injection of mercury. These experiments do not give us the natural pathway of the blood." But, in his second letter, he describes how he has examined, with a microscope of two lenses, the lung and the mesentery of a frog, and has seen the capillaries, and the blood in them:-- "Such is the divarication of these little vessels, coming off from the vein and the artery, that the order in which the vessel ramifies is no longer preserved, but it looks like a network woven from the offshoots of both vessels." He was able, in a dead frog, to see the capillaries; and then, in a living frog, to see the blood moving in them. But, in spite of this work, it took nearly half a century before Harvey's teaching was believed by all men--_Tantum consuetudo apud omnes valet_. 2. _The Blood-pressure_ Harvey had seen the facts of blood-pressure--_the great quantity of blood passing through, and the swiftness of its passage_--but he had not measured it. Keill's experiments on the blood-pressure (1718) were inexact, and of no value; and the first exact measurements were made by Stephen Hales, who was rector of Farringdon, Hampshire, and minister of Teddington, Middlesex; a Doctor of Divinity, and a Fellow of the Royal Society. His experiments, in their width and diversity, were not surpassed even by those of John Hunter, and were extended far over physiology, vegetable physiology, organic and inorganic chemistry, and physics; they ranged from the invention of a sea-gauge to the study of solvents for the stone, and he seems to have experimented on every force in Nature. The titles of his two volumes of _Statical Essays_ (1726-1733) show the great extent of his non-clerical work:-- Volume I. _Statical Essays, containing Vegetable Statics, or an Account of some Statical Experiments on the Sap in Vegetables, being an Essay towards a Natural History of Vegetation; also, a Specimen of an Attempt to Analyse the Air, by a great Variety of Chymio-Statical Experiments._ Volume II. _Statical Essays, containing Hæmostatics, or an Account of some Hydraulic and Hydrostatical Experiments made on the Blood and Blood-vessels of Animals; also, an Account of some Experiments on Stones in the Kidneys and Bladder, with an Enquiry into the Nature of those anomalous Concretions._ "We can never want matter for new experiments," he says in his preface. "We are as yet got little further than to the surface of things: we must be content, in this our infant state of knowledge, while we know in part only, to imitate children, who, for want of better skill and abilities, and of more proper materials, amuse themselves with slight buildings. The farther advances we make in the knowledge of Nature, the more probable and the nearer to truth will our conjectures approach: so that succeeding generations, who shall have the benefit and advantage both of their own observations and those of preceding generations, may then make considerable advances, when _many shall run to and fro, and knowledge shall be increased_." His account of his plan of measuring the blood-pressure, and of one of many experiments that he made on it, is as follows:-- "Finding but little satisfaction in what had been attempted on this subject by Borellus and others, I endeavoured, about twenty-five years since, by proper experiments, to find what was the real force of the blood in the crural arteries of dogs, and about six years afterwards I repeated the like experiments on two horses, and a fallow doe; but did not then pursue the matter any further, being discouraged by the disagreeableness of anatomical dissections. But having of late years found by experience the advantage of making use of the statical way of investigation, not only in our researches into the nature of vegetables, but also in the chymical analysis of the air, I was induced to hope for some success, if the same method of enquiry were applied to animal bodies.... "Having laid open the left crural artery (of a mare), I inserted into it a brass pipe whose bore was 1/6 of an inch in diameter; and to that, by means of another brass pipe which was fitly adapted to it, I fixed a glass tube of nearly the same diameter, which was 9 feet in length; then, untying the ligature on the artery, the blood rose in the tube 8 feet 3 inches perpendicular above the level of the left ventricle of the heart, but it did not attain to its full height at once: it rushed up gradually at each pulse 12, 8, 6, 4, 2, and sometimes 1 inch. When it was at its full height, it would rise and fall at and after each pulse 2, 3, or 4 inches, and sometimes it would fall 12 or 14 inches, and have there for a time the same vibrations up and down, at and after each pulse, as it had when it was at its full height, to which it would rise again, after forty or fifty pulses." 3. _The Collateral Circulation_ After Hales, came John Hunter, who was five years old when the _Statical Essays_ were published. His experiments on the blood were mostly concerned with its properties, not with its course; but one great experiment must be noted here that puts him in line with Harvey, Malpighi, and Hales. He got from it his knowledge of the collateral circulation; he learned how the obstruction of an artery is followed by enlargement of the vessels in its neighbourhood, so that the parts beyond the obstruction do not suffer from want of blood: and the facts of collateral circulation were fresh in his mind when, a few months later, he conceived and performed his operation for aneurysm (December 1785). The "old operation" gave him no help here; and "Anel's operation" was but a single instance, and no sure guide for Hunter, because Anel's patient had a different sort of aneurysm. Hunter knew that the collateral circulation could be trusted to nourish the limb, if the femoral artery were ligatured in "Hunter's canal" for the cure of popliteal aneurysm; and he got this knowledge from the experiment that he had made on one of the deer in Richmond Park, to see the influence of ligature of the carotid artery on the growth of the antler. The following account of this experiment was given by Sir Richard Owen, who had it from Mr. Clift, Hunter's devoted pupil and friend:-- "In the month of July, when the bucks' antlers were half-grown, he caused one of them to be caught and thrown; and, knowing the arterial supply to the hot 'velvet,' as the keepers call it, Hunter cut down upon and tied the external carotid; upon which, laying his hand upon the antler, he found that the pulsations of the arterial channels stopped, and the surface soon grew cold. The buck was released, and Hunter speculated on the result--whether the antler, arrested at mid-growth, would be shed like the full-grown one, or be longer retained. A week or so afterward he drove down again to the park, and caused the buck to be caught and thrown. The wound was healed about the ligature; but on laying his hand on the antler, he found to his surprise that the warmth had returned, and the channels of supply to the velvety formative covering were again pulsating. His first impression was that his operation had been defective. To test this, he had the buck killed and sent to Leicester Square. The arterial system was injected. Hunter found that the external carotid had been duly tied. But certain small branches, coming off on the proximal or heart's side of the ligature, had enlarged; and, tracing-on these, he found that they had anastomosed with other small branches from the distal continuation of the carotid, and these new channels had restored the supply to the growing antler.... Here was a consequence of his experiment he had not at all foreseen or expected. A new property of the living arteries was unfolded to him." All the anatomists had overlooked this physiological change in the living body, brought about by disease. And the surgeons, since anatomy could not help them, had been driven by the mortality of the "old operation" to the practice of amputation. 4. _The Mercurial Manometer_ Hale's experiments on the blood-pressure were admirable in their time; but neither he nor his successors could take into account all the physiological and mathematical facts of the case. But a great advance was made in 1828, when Poiseuille published his thesis, _Sur la Force du Coeur Aortique_, with a description of the mercurial manometer. Poiseuille had begun with the received idea that the blood-pressure in the arteries would vary according to the distance from the heart, but he found by experiment that this doctrine was wrong:-- "At my first experiments, wishing to make sure whether the opinions, given _à priori_, were true, I observed to my great astonishment that two tubes, applied at the same time to two arteries at different distances from the heart, gave columns of exactly the same height, and not, as I had expected, of different heights. This made the work very much simpler, because, to whatever artery I applied the instrument, I obtained the same results that I should have got by placing it on the ascending aorta itself." He found also, by experiments, that the coagulation of the blood in the tube could be prevented by filling one part of the tube with a saturated solution of sodium carbonate. The tube, thus prepared, was connected with the artery by a fine cannula, exactly fitting the artery. With this instrument, Poiseuille was able to obtain results far more accurate than those of Hales, and to observe the diverse influences of the respiratory movements on the blood-pressure. He sums up his results in these words:-- "I come to this irrevocable conclusion, that the force with which a molecule of blood moves, whether in the carotid, or in the aorta, etc., is exactly equal to the force which moves a molecule in the smallest arterial branch; or, in other words, that a molecule of blood moves with the same force over the whole course of the arterial system--which, _à priori_, with all the physiologists, I was far from thinking." And he adds, in a footnote:-- "When I say that this force is the same over the whole course of the arterial system, I do not mean to deny that it must needs be modified at certain points of this system, which present a special arrangement, such as the anastomosing arches of the mesentery, the arterial circle of Willis, etc." Later, in 1835, he published a very valuable memoir on the movement of the blood in the capillaries under different conditions of heat, cold, and atmospheric pressure. 5. _The Registration of the Blood-pressure_ Poiseuille's work, in its turn, was left behind as physiology went forward: especially, the discovery of the vaso-motor nerves compelled physiologists to reconsider the whole subject of the blood-pressure. If Poiseuille's thesis (1828) be compared with Marey's book (1863), _Physiologie Médicale de la Circulation du Sang_, it will be evident at once how much wider and deeper the problem had become. Poiseuille's thesis is chiefly concerned with mathematics and hydrostatics; it suggests no method of immediate permanent registration of the pulse, and is of no great value to practical medicine: Marey's book, by its very title, shows what a long advance had been made between 1828 and 1863--_Physiologie Médicale de la Circulation du Sang, basée sur l'étude graphique des mouvements du coeur et du pouls artériel, avec application aux maladies de l'appareil circulatoire_. Though the contrast is great between Hales' may-pole and Poiseuille's manometer, there is even a greater contrast between Poiseuille's mathematical calculations and Marey's practical use of the sphygmograph for the study of the blood-pressure in health and disease. Marey had the happiness of seeing medicine, physiology, and physics, all three of them working to one end:-- "La circulation du sang est un des sujets pour lesquels la médecine a le plus besoin de s'éclairer de la physiologie, et où celle-ci à son tour tire le plus de lumière des sciences physiques. Ces dernières années sont marquées par deux grands progrès qui ouvrent aux recherches à venir des horizons nouveaux: en Allemagne, l'introduction des procédés graphiques dans l'étude du mouvement du sang; en France, la démonstration de l'influence du système nerveux sur la circulation périphérique. Cette dernière découverte, que nous devons à M. Cl. Bernard, et qui depuis dix ans a donné tant d'impulsion à la science, montre mieux que toute autre combien la physiologie est indispensable à la médecine, tandis que les travaux allemands ont bien fait ressortir l'importance des connaissances physiques dans les études médicales." Marey's sphygmograph was not the first instrument of its kind. There had been, before it, Hérisson's sphygmometer, Ludwig's kymographion, and the sphygmographs of Volckmann, King, and Vierordt. But, if one compares a Vierordt tracing with a Marey tracing, it will be plain that Marey's results were far advanced beyond the useless "oscillations isochrones" recorded by Vierordt's instrument. Beside this improved sphygmograph, Chauveau and Marey also invented the cardiograph, for the observation of the blood-pressure within the cavities of the heart. Their cardiograph was a set of very delicate elastic tambours, resting on the heart, or passed through fine tubes into the cavities of the heart,[1] and communicating impulses to levers with writing-points. These writing-points, touching a revolving cylinder, recorded the variations of the endocardial pressure, and the duration of the auricular and ventricular contractions. [1] "On peut s'assurer de l'innocuité de ce premier temps de l'expérience en examinant l'animal, qui n'est nullement troublé, qui marche et mange comme de coutume. En comptant le chiffre du pouls, on trouve quelquefois une légère accéleration, surtout dans les premiers instants; mais les mouvements du coeur sont toujours réguliers, et donnent, à l'auscultation, des bruits d'un caractère normal." (Marey, _loc. cit._ p. 63.) * * * * * It is impossible here to describe the subsequent study of those more abstruse problems that the older physiologists had not so much as thought of: the minutest variations of the blood-pressure, the multiple influences of the nervous system on the heart and blood-vessels, the relations between blood-pressure and secretion, the automatism of the heart-beat, the influence of gravitation, and other finer and more complex issues of physiology. But, even if one stops at Marey's book, now more than forty years old, there is an abundant record of good work, from the discovery of the circulation to the invention of the sphygmograph. II THE LACTEALS Asellius, in his account of his discovery of the lacteal vessels (1622), is of opinion that certain of "the ancients" had seen these vessels, but had not recognised them. He has a great reverence for authority: Hippocrates, Plato, Aristotle, the Stoics, Herophilus, Galen, Pollux, Rhases, and a host of other names, he quotes them all, and all with profound respect; and comes to this conclusion: "It did not escape the ancients, that certain vessels must needs be concerned with containing and carrying the chyle, and certain other vessels with the blood: but the true and very vessels of the chyle, that is, my 'veins,' though they were seen by some of the ancients, yet they were recognised by none of them." He can forgive them all, except Galen, _qui videtur nosse omnino debuisse_--"but, as for Galen, I know not at all what I am to think. For he, who made more than six hundred sections of living animals, as he boasts himself, and so often opened many animals when they were lately fed, are we to think it possible that these veins never showed themselves to him, that he never had them under his eyes, that he never investigated them--he to whom Erasistratus had given so great cause for searching out the whole matter?" Probably, the milk-white threads had been taken for nerves by those who had seen them: and those who had never seen them, but believed in their existence, rested their belief on a general idea that the chyle must, somehow, have vessels of its own apart from the blood-vessels. What Galen and Erasistratus must have seen, Asellius and Pecquet discovered: and Harvey gives a careful review of the discovery in his letters to Nardi (May 1652) and to Morison (November 1653). He does not accept it; but the point is that he recognises it as a new thing altogether. A year or two after he had made the discovery, Asellius died; and his work was published in 1627 by two Milanese physicians, and was dedicated by them to the senate of the Academy of Milan, where Asellius had been professor of anatomy. The full title of his book is, _De Lactibus sive Lacteis Venis, quarto Vasorum Mesaraicorum genere novo invento, Gasparis Asellii Cremonensis, Anatomici Ticinensis, Dissertatio. Quâ sententiæ anatomicæ multæ vel perperam receptæ convelluntur vel partim perceptæ illustrantur._ He gives the following account of the discovery, in the chapter entitled _Historia primæ vasorum istorum inventionis cum fide narrata_. On 23rd July 1622, demonstrating the movement of the diaphragm in a dog, he observed suddenly, "as it were, many threads, very thin and very white, dispersed through the whole mesentery and through the intestines, with ramifications almost endless"--_plurimos, eosque tenuissimos candido-sissimosque ceu funiculos per omne mesenterium et per intestina infinitis propemodum propaginibus dispersos_:-- "Thinking at first sight that they were nerves, I did not greatly heed them. But soon I saw that I was wrong, for I bethought me that the nerves, which belong to the intestines, are distinct from these threads, and very different from them, and have a separate course. Wherefore, struck by the newness of the matter, I stopped for a time silent, while one way and another there came to my mind the controversies that occupy anatomists, as to the mesenteric veins and their use; which controversies are as full of quarrels as of words. When I had pulled myself together, to make experiment, taking a very sharp scalpel, I pierce one of the larger threads. Scarcely had I hit it off, when I see a white fluid running out, like milk or cream. At which sight, when I could not hold my joy, turning to those who were there, first to Alexander Tadinus and Senator Septalius, both of them members of the most honourable College of Physicians, and, at the time of this writing, officers of the public health, '_I have found it_,' I say like Archimedes; and therewith invite them to the so pleasant sight of a thing so unwonted; they being agitated, like myself, by the newness of it." He then describes the collapse and disappearance of the vessels at death, and the many experiments which he made for further study of them; and the failure, when he tried to find them in animals not lately fed. He did not trace them beyond the mesentery, and believed that they emptied themselves into the liver. The discovery of their connection with the receptaculum chyli and the thoracic duct was made by Jehan Pecquet of Dieppe, Madame de Sévigné's doctor, her "good little Pecquet." The full title of his book (2nd ed., 1654) is, _Expérimenta Nova Anatomica, quibus incognitum hactenus Receptaculum, et ab eo per Thoracem in ramos usque subclavios Vasa Lactea deteguntur_. He has not the academical learning of Asellius, nor his obsequious regard for the ancients; and the discovery of the thoracic duct came, as it were by chance, out of an experiment that was of itself wholly useless. He had killed an animal by removing its heart, and then saw a small quantity of milky fluid coming from the cut end of the vena cava--_Albicantem subinde Lactei liquoris, nec certe parum fluidi scaturiginem, intra Venæ Cavæ fistulam, circ[=a] dextri sedem Ventriculi, miror effluere_--and found that this fluid was identical with the chyle in the lacteals. In another experiment, he succeeded in finding the thoracic duct--"At last, by careful examination deep down along the sides of the dorsal vertebræ, a sort of whiteness, as of a lacteal vessel, catches my eyes. It lay in a sinuous course, close up against the spine. I was in doubt, for all my scrutiny, whether I had to do with a nerve or with a vessel. Therefore, I put a ligature a little below the clavicular veins; and then the flaccidity above the ligature, and the swelling of the distended duct below the ligature, broke down my doubt--_Ergo subducto paulo infra Claviculas vinculo, cum a ligaturâ sursum flaccesceret, superstite deorsum turgentis alveoli tumore, dubium meum penitus enervavit.... Laxatis vinculis, lacteus utrinque rivulus in Cavam affatim Chylum profudit._" It is to be noted that Asellius and Pecquet, both of them, made their discoveries as it were by chance. Unless digestion were going on, the lacteals would be empty and invisible; and, on the dead body, lacteals, receptaculum, and thoracic duct would all be empty. For these reasons, it cost a vast number of experiments to prove the existence, and to discover the course, of these vessels. Once found in living animals, they could be injected and dissected in the dead body; but they had been overlooked by Vesalius and the men of his time. From the discovery of the lacteals came the discovery of the whole lymphatic system. Daremberg, in his _Histoire des Sciences Médicales_ (Paris, 1870), after an account of Pecquet's work, says:-- "Up to this point, we have seen English, Italians, and French working together, with more or less success and genius, to trace the true ways of blood and chyle: there is yet one field of work to open up, the lymphatics of the body. The chief honour here belongs, without doubt, to the Swede Rudbeck, though the Dane Bartholin has disputed it with him, with equal acrimony and injustice." Rudbeck's work (1651-54) coincides exactly, in point of time, with the first and second editions, 1651 and 1654, of Pecquet's _De Lactibus_. It may be said, therefore, that the whole doctrine of the lymphatic system was roughed out half-way through the seventeenth century. III THE GASTRIC JUICE From many causes, the experimental study of the digestive processes came later than the study of the circulation. As an object of speculative thought, digestion was a lower phase of life, the work of crass spirits, less noble than the blood; from the point of view of science, it could not be studied ahead of organic chemistry, and got no help from any other sort of knowledge; and, from the medical point of view, it was the final result of many unknown internal forces that could not be observed or estimated either in life or after death. It did not, like the circulation, centre itself round one problem; it could not be focussed by the work of one man. For these reasons, and especially because of its absolute dependence on chemistry for the interpretation of its facts, it had to bide its time; and Réaumur's experiments are separated from the publication of Harvey's _De Motu Cordis et Sanguinis_ by a hundred and thirty years. The following account of the first experiments on digestion is taken from Claude Bernard's _Physiologie Opératoire_, 1879:-- "The true experimental study of digestion is of comparatively recent date; the ancients were content to find comparisons, more or less happy, with common facts. Thus, for Hippocrates, digestion was a 'coction': for Galen, a 'fermentation,' as of wine in a vat. In later times, van Helmont started this comparison again: for him, digestion was a fermentation like that of bread: as the baker, having kneaded the bread, keeps a little of the dough to leaven the next lot kneaded, so, said van Helmont, the intestinal canal never completely empties itself, and the residue that it keeps after each digestion becomes the leaven that shall serve for the next digestion. "The first experimental studies on the digestion date from the end of the seventeenth century, when the Academy of Florence was the scene of a famous and long controversy between Borelli and Valisnieri. The former saw nothing more in digestion than a purely mechanical act, a work of attrition whereby the ingesta were finely divided and as it were pulverised: and in support of this opinion Borelli invoked the facts that he had observed relating to the gizzard of birds. We know that this sac, with its very thick muscular walls, can exercise on its contents pressure enough to break the hardest bodies. Identifying the human stomach with the bird's gizzard, Borelli was led to attribute to the walls of the stomach an enormous force, estimated at more than a thousand pounds; whose action, he said, was the very essence of digestion. Valisnieri, on the contrary, having had occasion to open the stomach of an ostrich, had found there a fluid which seemed to act on bodies immersed in it; this fluid, he said, was the active agent of digestion, a kind of _aqua fortis_ that dissolved food. "These two opposed views, resulting rather from observations than from regularly instituted experiments, were the starting-point of the experimental researches undertaken by Réaumur in 1752. To resolve the problem set by Borelli and Valisnieri, Réaumur made birds swallow food enclosed in fenestrated tubes, so that the food, protected from the mechanical action of the walls of the stomach, was yet exposed to the action of the gastric fluid. The first tubes used (glass, tin, etc.) were crushed, bent, or flattened by the action of the walls of the gizzard; and Réaumur failed to oppose to this force a sufficient resistance, till he employed leaden tubes thick enough not to be flattened by a pressure of 484 pounds: which was, in fact, the force exercised by the contractile walls of the gizzard in turkeys, ducks, and fowls under observation. These leaden tubes--filled with ordinary grain, and closed only by a netting that let pass the gastric juices--these tubes, after a long stay in the stomach, still enclosed grain wholly intact, unless it had been crushed before the experiment. When they were filled with meat, it was found changed, but not digested. Réaumur was thus led at first to consider digestion, in the gallinaceæ, as pure and simple trituration. But, repeating these experiments on birds of prey, he observed that digestion in them consists essentially in dissolution, without any especial mechanical action, and that it is the same with the digestion of meat in all animals with membranous stomachs. To procure this dissolving fluid, Réaumur made the birds swallow sponges with threads attached: withdrawing these sponges after a definite period, he squeezed the fluid into a glass, and tested its action on meat. That was the first attempt at artificial digestion _in vitro_. He did not carry these last investigations very far, and did not obtain very decisive results; nevertheless he must be considered as the discoverer of artificial digestion." After Réaumur, the Abbé Spallanzani (1783) made similar observations on many other animals, including carnivora. He showed that even in the gallinaceæ there was dissolution of food, not mere trituration: and observed how after death the gastric fluid may under certain conditions act on the walls of the stomach itself. "Henceforth the experimental method had cut the knot of the question raised by the theories of Borelli and Valisnieri: digestion could no longer be accounted anything but a dissolution of food by the fluid of the stomach, the gastric juice. But men had still to understand this gastric juice, and to determine its nature and mode of action. Nothing could be more contradictory than the views on this matter. Chaussier and Dumas, of Montpellier, regarded the gastric juice as of very variable composition, one time alkaline, another acid, according to the food ingested. Side by side with these wholly theoretical opinions, certain results of experiments had led to ideas just as erroneous, for want of rigorous criticism of methods; it was thus that Montègre denied the existence of the gastric juice as a special fluid; what men took for gastric juice, he said, was nothing but the saliva turned acid in the stomach. To prove his point, he made the following experiment:--He masticated a bit of bread, then put it out on a plate; it was at first alkaline, then at the end of some time it became acid. In those days (1813) this experiment was a real embarrassment to the men who believed in the existence of a special gastric juice: we have now no need to refute it. "These few instances suffice to show how the physiologists were unsettled as to the nature and properties of the gastric juice. Then (1823) the Academy had the happy idea of proposing digestion as a subject for a prize. Tiedemann and Gmelin in Germany, Leuret and Lassaigne in France, submitted works of equal merit, and the Academy divided the prize between them. The work of Tiedemann and Gmelin is of especial interest to us on account of the great number of their experiments, from which came not only the absolute proof of the existence of the gastric juice, but also the study of the transformation of starch into glucose. Thus the theory of digestion entered a new phase: it was finally recognised, at least for certain substances, that digestion is not simply dissolution, but a true chemical transformation." (Cl. Bernard, _loc. cit._) In 1825 Dr. William Beaumont, a surgeon in the United States Army, began his famous experiments on Alexis St. Martin, a young Canadian travelling for the American Fur Company, who was shot in the abdomen on 6th June 1822, and recovered, but was left with a permanent opening in his stomach. Since the surgery of those days did not favour an operation to close this fistula, Dr. Beaumont took St. Martin into his service, and between 1825 and 1833 made a vast number of experiments on him. These he published,[2] and they were of great value. But it is to be noted that the ground had been cleared already, fifty years before, by Réaumur and Spallanzani:-- "_I make no claim to originality in my opinions_, as it respects the existence and operation of the gastric juice. My experiments confirm the doctrines (with some modifications) taught by Spallanzani, and many of the most enlightened physiological writers." (Preface to Dr. Beaumont's book.) [2] _Experiments and Observations on the Gastric Juice, and the Physiology of Digestion_, by William Beaumont, M.D.; Edinburgh, 1838. Further, it is to be noted that Alexis St. Martin's case proves that a gastric fistula is not painful. Scores of experiments were made on him, off and on, for nine years:-- "During the whole of these periods, from the spring of 1824 to the present time (1833), he has enjoyed general good health, and perhaps suffered much less predisposition to disease than is common to men of his age and circumstances in life. He has been active, athletic, and vigorous; exercising, eating, and drinking like other healthy and active people. For the last four months he has been unusually plethoric and robust, though constantly subjected to a continuous series of experiments on the interior of the stomach; allowing to be introduced or taken out at the aperture different kinds of food, drinks, elastic catheters, thermometer tubes, gastric juice, chyme, etc., almost daily, and sometimes hourly. "Such have been this man's condition and circumstances for several years past; and he now enjoys the most perfect health and constitutional soundness, with every function of the system in full force and vigour." (Dr. Beaumont, _loc. cit_. p. 20.) In 1834 Eberlé published a series of observations on the extraction of gastric juice from the mucous membrane of the stomach after death; in 1842 Blondlot of Nancy studied the gastric juice of animals by the method of a fistula, such as Alexis St. Martin had offered for Dr. Beaumont's observation. After Blondlot, came experiments on the movements of the stomach, and on the manifold influences of the nervous system on digestion. It has been said, times past number, that an animal with a fistula is in pain. It is not true. The case of St. Martin is but one out of a multitude of these cases: an artificial orifice of this kind is not painful. IV GLYCOGEN Claude Bernard's discovery of glycogen in the liver had a profound influence both on physiology and on pathology. Take first its influence on pathology. Diabetes was known to Celsus, Aretæus, and Galen; Willis, in 1674, and Morton, in 1675, noted the distinctive sweetness of the urine; and their successors proved the presence of sugar in it. Rollo, in 1787, observed that vegetable food was bad for diabetic patients, and introduced the strict use of a meat diet. But Galen had believed that diabetes was a disease of the kidneys, and most men still followed him: nor did Rollo greatly advance pathology by following not Galen, but Aretæus. Later, with the development of organic chemistry, came the work of Chevreuil (1815), Tiedemann and Gmelin (1823), and other illustrious chemists: and the pathology of diabetes grew more and more difficult:-- "These observations gave rise to two theories: the one, that sugar is formed with abnormal rapidity in the intestine, absorbed into the blood, and excreted in the urine; the other, that diabetes is due to imperfect destruction of the sugar, either in the intestine or in the blood. Some held that it underwent conversion into lactic acid as it was passing through the intestinal walls, while others believed it to be destroyed in the blood by means of the alkali therein contained."[3] [3] _Reynolds' System of Medicine_, vol. v., art. "Diabetes Mellitus." Thus, before Claude Bernard (1813-1878), the pathology of diabetes was almost worthless. And, in physiology, his work was hardly less important than the work of Harvey. A full account of it, in all its bearings, is given in Sir Michael Foster's _Life of Claude Bernard_ (Fisher Unwin, 1899). In Bernard's _Leçons sur le Diabète et la Glycogenèse Animale_ (Paris, 1877), there is a sentence that has been misquoted many times:-- _Sans doute, nos mains sont vides aujourd'hui, mais notre bouche peut être pleine de légitimes promesses pour l'avenir._ This sentence has been worked so hard that some of the words have got rubbed off it: and the statement generally made is of this kind:-- _Claude Bernard himself confessed that his hands were empty, but his mouth was full of promises._ Of course, he did not mean that he was wrong in his facts. But, in this particular lecture, he is speaking of the want of more science in practice, looking forward to a time when treatment should be based on science, not on tradition. Medicine, he says, is neither science nor art. Not science--_Trouverait-on aujourd'hui un seul médecin raisonnable et instruit osant dire qu'il prévoit d'une manière certaine la marche et l'issue d'une maladie ou l'effet d'une remède?_ Not art, because art has always something to show for its trouble: a statue, a picture, a poem--_Le médecin artiste ne crée rien, et ne laisse aucune oeuvre d'art, à moins d'appliquer ce titre à la guérison du malade. Mais quand le malade meurt, est-ce également son oeuvre? Et quand il guérit, peut-il distinguer sa part de celle de la nature?_ To Claude Bernard, experiments on animals for the direct advancement of medicine seemed a new thing: new, at all events, in comparison with the methods of some men of his time. He was only saying what Sir John Burdon Sanderson said in 1875 to the Royal Commission:-- _It is my profound conviction that a future will come, it may be a somewhat distant future, in which the treatment of disease will be really guided by science. Just as completely as mechanical science has come to be the guide of the mechanical arts, do I believe, and I feel confident, that physiological science will eventually come to be the guide of medicine and surgery._ Anyhow, lecturing a quarter of a century ago on diabetes, his special subject, Claude Bernard spoke out his longing to compel men into the ways of science, to give them some immediate sign which they could not refuse to see:-- "At this present time, medicine is passing from one period to another. The old traditions are losing ground, and scientific medicine (_la médecine expérimentale_) has got hold of all our younger men: every day it gains ground, and will establish itself against all its critics, and in spite of the excesses of those who are over-zealous for its honour.... And when men ask us what are the results of scientific medicine, we are driven to answer that it is scarcely born, that it is still in the making. Those who care for nothing but an immediate practical application must remember Franklin's words, _What is the use of a new-born child, but to become a man?_ If you deliberately reject scientific medicine, you fail to see the natural development of man's mind in all the sciences. Without doubt, our hands are empty to-day, but our mouth may well be filled with legitimate promises for the future." He died in 1878. The following account of the discovery of glycogen is taken from his _Nouvelle Fonction du Foie_ (Paris, 1853):-- "My first researches into the assimilation and destruction of sugar in the living organism were made in 1843: and in my inaugural thesis (Dec. 1843) I published my first experiments on the subject. I succeeded in demonstrating a fact hitherto unknown, that cane-sugar cannot be directly destroyed in the blood. If you inject even a very small quantity of cane-sugar, dissolved in water, into the blood or under the skin of a rabbit, you find it again in the urine unchanged, with all its chemical properties the same.... I had soon to give up my first point of view, because this question of the existence of a sugar-producing organ, that I had thought such a hard problem of physiology, was really the first thing revealed to me, as it were of itself, at once." He kept two dogs on different diets, one with sugar, the other without it; then killed them during digestion, and tested the blood in the hepatic veins:-- "What was my surprise, when I found a considerable quantity of sugar in the hepatic veins of the dog that had been fed on meat only, and had been kept for eight days without sugar: just as I found it in the other dog that had been fed for the same time on food rich in sugar.... "Finally, after many attempts--_après beaucoup d'essais et plusieurs illusions que je fus obligé de rectifier par des tâtonnements_--I succeeded in showing, that in dogs fed on meat the blood passing through the portal vein does not contain sugar before it reaches the liver; but when it leaves the liver, and comes by the hepatic veins into the inferior vena cava, this same blood contains a considerable quantity of a sugary substance (glucose)." His further discovery, that this formation of sugar is increased by puncture of the floor of the fourth ventricle, was published in 1849. It is impossible to exaggerate the importance of Claude Bernard's single-handed work in this field of physiology and pathology:-- "As a mere contribution to the history of sugar within the animal body, as a link in the chain of special problems connected with digestion and nutrition, its value was very great. Even greater, perhaps, was its effect as a contribution to general views. The view that the animal body, in contrast to the plant, could not construct, could only destroy, was, as we have seen, already being shaken. But evidence, however strong, offered in the form of numerical comparisons between income and output, failed to produce anything like the conviction which was brought home to every one by the demonstration that a substance was actually formed within the animal body, and by the exhibition of the substance so formed. "No less revolutionary was the demonstration that the liver had other things to do in the animal economy besides secreting bile. This, at one blow, destroyed the then dominant conception that the animal body was to be regarded as a bundle of organs, each with its appropriate function, a conception which did much to narrow inquiry, since when a suitable function had once been assigned to an organ there seemed no need for further investigations.... "No less pregnant of future discoveries was the idea suggested by this newly-found-out action of the hepatic tissue, the idea happily formulated by Bernard as 'internal secretion.' No part of physiology is at the present day being more fruitfully studied than that which deals with the changes which the blood undergoes as it sweeps through the several tissues, changes by the careful adaptation of which what we call the health of the body is secured, changes the failure or discordance of which entails disease. The study of these internal secretions constitutes a path of inquiry which has already been trod with conspicuous success, and which promises to lead to untold discoveries of the greatest moment; the gate to this path was opened by Bernard's work." (Sir M. Foster, _loc. cit._) But the work to be done, before all the clinical facts of the disease can be stated in terms of physiology, is not yet finished. In England, especial honour is due to Dr. Pavy for his life-long study of this most complex problem. V THE PANCREAS Here again Claude Bernard's name must be put first. Before him, the diverse actions of the pancreatic juice had hardly been studied. Vesalius, greatest of all anatomists, makes no mention of the duct of the pancreas, and speaks of the gland itself as though its purpose were just to support the parts in its neighbourhood--_ut ventriculo instar substerniculi ac pulvinaris subjiciatur_. The duct was discovered by Wirsung, in 1642: but anatomy could not see the things that belong to physiology. Lindanus (1653) said, _I cannot doubt that the pancreas expurgates, in the ordinary course of Nature, those impurities of the blood that are too crass and inept to be tamed by the spleen: and, in the extraordinary course, all black bile, begotten of disease or intemperate living_. Wharton (1656) said, _It ministers to the nerves, taking up certain of their superfluities, and remitting them through its duct into the intestines_. And Tommaso Bartholini (1666) called it the _biliary vesicle of the spleen_. This chaos of ideas was brought into some sort of order by Regnier de Graaf, pupil of François de Bois (Sylvius). De Bois had guessed that the pancreas must be considered not according to its position in the body, but according to its structure: that it was analogous to the salivary glands. He urged his pupil to make experiments on it: and de Graaf says:-- "I put my hand to the work: and though many times I despaired of success, yet at last, by the blessing of God on my work and prayers, in the year 1660 I discovered a way of collecting the pancreatic juice." And, by further experiment, he refuted Bartholini's theory that the pancreas was dependent on the spleen. Sylvius had supposed that the pancreatic juice was slightly acid, and de Graaf failed to note this mistake; but it was corrected by Bohn's experiments in 1710. Nearly two hundred years come between Regnier de Graaf and Claude Bernard: it is no wonder that Sir Michael Foster says that de Graaf's work was "very imperfect and fruitless." So late as 1840, there was yet no clear understanding of the action of the pancreas. Physiology could not advance without organic chemistry; de Graaf could no more discover the amylolytic action of the pancreatic juice than Galvani could invent wireless telegraphy. The physiologists had to wait till chemistry was ready to help them:-- "Of course, while physical and chemical laws were still lost in a chaos of undetermined facts, it was impossible that men should analyse the phenomena of life: first, because these phenomena go back to the laws of chemistry and physics; and next, because they cannot be studied without the apparatus, instruments, and all other methods of analysis that we owe to the laboratories of the chemists and the physicists." (Cl. Bernard, _Phys. Opér._, p. 61.) Therefore de Graaf failed, because he got no help from other sciences. But it cannot be called failure; he must be contrasted with the men of his time, Lindanus and Bartholini, facts against theories, not with men of this century. And Claude Bernard went back to de Graaf's method of the fistula, having to guide him the facts of chemistry observed by Valentin, Tiedemann and Gmelin, and Eberlé. His work began in 1846, and the Académie des Sciences awarded a prize to it in 1850:-- "Let this vague conception (the account of the pancreas given in Johannes Müller's Text-book of Physiology) be compared with the knowledge which we at present have of the several distinct actions of the pancreatic juice, and of the predominant importance of this fluid not only in intestinal digestion but in digestion as a whole, and it will be at once seen what a great advance has taken place in this matter since the early forties. That advance we owe in the main to Bernard. Valentin, it is true, had in 1844 not only inferred that the pancreatic juice had an action on starch, but confirmed his view by actual experiment with the juice expressed from the gland; and Eberlé had suggested that the juice had some action on fat; but Bernard at one stroke made clear its threefold action. He showed that it on the one hand emulsified, and on the other hand split up, into fatty acids and glycerine, the neutral fats; he clearly proved that it had a powerful action on starch, converting it into sugar; and lastly, he laid bare its remarkable action on proteid matters." (Sir Michael Foster, _loc. cit._) Finally came the discovery that the pancreas--apart from its influences on digestion--contributes its share, like the ductless glands, to the general chemistry of the body:-- "It was discovered, a few years ago, by von Mering and Minkowski, that if, instead of merely diverting its secretion, the pancreas is bodily removed, the metabolic processes of the organism, and especially the metabolism of carbo-hydrates, are entirely deranged, the result being the production of permanent diabetes. But if even a very small part of the gland is left within the body, the carbo-hydrate metabolism remains unaltered, and there is no diabetes. The small portion of the organ which has been allowed to remain (and which need not even be left in its proper place, but may be transplanted under the skin or elsewhere) is sufficient, by the exchanges which go on between it and the blood generally, to prevent those serious consequences to the composition of the blood, and the general constitution of the body, which result from the complete removal of this organ." (Prof. Schäfer, 1894.) Here, in this present study of "pancreatic diabetes," by Dr. Vaughan Harley and others, are facts as important as any that Bernard made out: in no way contradicting his work, but adding to it. The pancreas is no longer taken to be only a sort of salivary gland out of place: over and above the secretion that it pours into the intestines, it has an "internal secretion," a constituent of the blood: it belongs not only to the digestive system, but also, like the thyroid gland and the suprarenal capsules, to the whole chemistry of the blood and the tissues. So far has physiology come, unaided by anatomy, from the fantastic notions of Lindanus and the men of his time: and has come every inch of the way by the help of experiments on animals. Professor Starling's observations, on the chemical influence of the duodenal mucous membrane on the flow of pancreatic fluid, have advanced the subject still further. VI THE GROWTH OF BONE The work of du Hamel proved that the periosteum is one chief agent in the growth of bone. Before him, this great fact of physiology was unknown; for the experiments made by Anthony de Heide (1684), who studied the production of callus in the bones of frogs, were wholly useless, and serve only to show that men in his time had no clear understanding of the natural growth of bone. De Heide says of his experiments:-- "From these experiments it appears--_forsan probatur_--that callus is generated by extravasated blood, whose fluid particles being slowly exhaled, the residue takes the form of the bone: which process may be further advanced by deciduous halitus from the ends of the broken bone." And Clopton Havers, in his _Osteologia Nova_ (London, 1691), goes so far the wrong way that he attributes to the periosteum not the production of bone, but the prevention of over-production; the periosteum, he says, is put round the shaft of a bone to compress it, lest it grow too large. Du Hamel's discovery (1739-1743) came out of a chance observation, made by John Belchier,[4] that the bones of animals fed near dye-works were stained with the dye. Belchier therefore put a bird on food mixed with madder, and found that its bones had taken up the stain. Then du Hamel studied the whole subject by a series of experiments. To estimate the advance that he gave to physiology, contrast de Heide's fanciful language with the title of one of du Hamel's papers--_Quatrième Mémoire sur les Os, dans lequel on se propose de rapporter de nouvelles preuves qui établissent que les os croissent en grosseur par l'addition de couches osseuses qui tirent leur origine du périoste, comme le corps ligneux des Arbres augmente en grosseur par l'addition de couches ligneuses qui se forment dans l'écorce._ Or take an example of du Hamel's method:-- "Three pigs were destined to clear up my doubts. The first, six weeks old, was fed for a month on ordinary food, with an ounce daily of madder-juice--_garence grappe_--put in it. At the end of the month, we stopped the juice, and fed the pig in the ordinary way for six weeks, and then killed it. The marrow of the bones was surrounded by a fairly thick layer of white bone: this was the formation of bone during the first six weeks of life, without madder. This ring of white bone was surrounded by another zone of red bone: this was the formation of bone during the administration of the madder. Finally, this red zone was covered with a fairly thick layer of white bone: this was the layer formed after the madder had been left off.... We shall have no further difficulty in understanding whence transudes the osseous juice that was thought necessary for the formation of callus and the filling-up of the wounds of the bones, now we see that it is the periosteum that fills up the wounds, or is made thick round the fractures, and afterward becomes of the consistence of cartilage, and at last acquires the hardness of bones." [4] "An Account of the Bones of Animals being changed to a Red Colour by Aliment only," by John Belchier, F.R.S., _Phil. Trans. Roy. Soc._, 1735-36. There is a letter from Sir Hans Sloane, then President of the Royal Society, to M. Geoffroy, member of the French Academy:--"M. Belchier, chirurgien, membre de cette Société, dînant un jour chez un Teinturier qui travaille en Toiles peintes, remarqua que dans un Porc frais qu'on avoit servi sur table, et dont la chair étoit de bon goût, les os étoient rouges. Il demanda la cause d'un effet si singulier, et on lui dit que ces sortes de Teinturiers se servoient de la racine de Rubia Tinctorum, ou garence, pour fixer les couleurs déjà imprimées sur les Toiles de coton, qu'on appelle en Angleterre callicoes." This passage of dye into the bones of animals had been noted so far back as 1573, by Antoine Mizald, a doctor in Paris--_Erythrodanum, vulgo rubia tinctorum, ossa pecudum rubenti et sandycino colore imbuit._ These results, confirmed by Bazan (1746) and Boehmer (1751), were far beyond anything that had yet been known about the periosteum. But the growth of bone is a very complex process: the naked eye sees only the grosser changes that come with it; and du Hamel's ingenious comparison between the periosteum and the bark of trees was too simple to be exact. Therefore his work was opposed by Haller, and by Dethleef, Haller's pupil: and the great authority of Haller's name, and the difficulties lying beyond du Hamel's plain facts, brought about a long period of uncertainty. Bordenave (1756) found reasons for supporting Haller; and Fougeroux (1760) supported du Hamel. Thus men came to study the whole subject with more accuracy--the growth in length, as well as the growth in thickness; the medullary cavity, the development of bone, the nutrition and absorption of bone. Among those who took up the work were Bichat, Hunter, Troja, and Cruveilhier; and they recognised the surgical aspect of these researches in physiology. After them, the periosteal growth of bone became, as it were, a part of the principles of surgery. From this point of view of practice, issued the experiments made by Syme (1837) and Stanley (1849): which proved the importance of the epiphysial cartilages for the growth of the bones in length, and the risk of interfering with these cartilages in operations on the joints of children. Finally, with the rise of anæsthetics and of the antiseptic method, came the work of Ollier, of Lyon, whose good influence on the treatment of these cases can hardly be over-estimated. VII THE NERVOUS SYSTEM As with the circulatory system, so with the nervous system, the work of Galen was centuries ahead of its time. Before him, Aristotle, who twice refers to experiments on animals, had observed the brain during life: for he says, "In no animal has the blood any feeling when it is touched, any more than the excretions; nor has the brain, or the marrow, any feeling, when it is touched": but there is reason for believing that he neither recognised the purpose of the brain, nor understood the distribution of the nerves. Galen, by the help of the experimental method, founded the physiology of the nervous system:-- "Galen's method of procedure was totally different to that of an anatomist alone. He first reviewed the anatomical position, and by dissection showed the continuity of the nervous system, both central and peripheral, and also that some bundles of nerve fibres were distributed to the skin, others to the muscles. Later, by process of the physiological experiment of dividing such bundles of fibres, he showed that the former were sensory fibres and the latter motor fibres. He further traced the nerves to their origins in the spinal cord, and their terminations as aforesaid. From these observations and experiments he was able to deduce the all-important fact that different nerve-roots supplied different groups of muscles and different areas of the skin.... An excellent illustration of his method, and of the fact that we ought not to treat symptoms, but the causes of symptoms, is shown very clearly in one of the cases which Galen records as having come under his care. He tells us that he was consulted by a certain sophist called Pausanias, who had a severe degree of anæsthesia of the little and ring fingers. For this loss of sensation, etc., the medical men who attended him applied ointments of various kinds to the affected fingers; but Galen, considering that that was a wrong principle, inquired into the history, and found that while the patient was driving in his chariot he had accidentally fallen out and struck his spine at the junction of the cervical and dorsal regions. Galen recognised that he had to do with a traumatism affecting the eighth cervical and first dorsal nerve; therefore, he says, he ordered that the ointments should be taken off the hand and placed over the spinal column, so as to treat the really affected part, and not apply remedies to merely the referred seat of pain."[5] [5] From an address on Galen, given by Sir Victor Horsley before the Medical Society of the Middlesex Hospital. See _Middlesex Hospital Journal_, May 1899. Galen, by this sort of work, laid the foundations of physiology; but the men who came after him let his facts be overwhelmed by fantastic doctrines: all through the ages, from Galen to the Renaissance, no great advance was made toward the interpretation of the nervous system. Long after the Renaissance, his authority still held good; his ghost was not laid even by Paracelsus and Vesalius, it haunted the medical profession so late as the middle of the seventeenth century; but the men who worshipped his name missed the whole meaning of his work. This long neglect of the experimental method left such a gap in the history of physiology, that Sir Charles Bell seems to take up the experimental study of the nervous system at the point where Galen had stopped short; we go from the time of Commodus to the time of George the Third, and there is Bell, as it were, putting the finishing touch to Galen's facts. It is true that experiments had been made on the nervous system by many men; but a dead weight of theories kept down the whole subject. For a good instance, how imagination hindered science, there is the following list, made by Dr. Risien Russell, of theories about the cerebellum:-- "Galen was of opinion that the cerebellum must be the originator of a large amount of vital force. After him, and up to the time of Willis, the prevalent idea seems to have been that it was the seat of memory; while Bourillon considered it the seat of instinct and intelligence. Willis supposed that it presided over involuntary movements and organic functions; and this view, though refuted by Haller, continued in the ascendency for some time. Some believed strongly in its influence on the functions of organic life; and according to some, diseases of the cerebellum appeared to tell on the movements of the heart.... Haller believed it to be the seat of sensations, as well as the source of voluntary power; and there were many supporters of the theory that the cerebellum was the seat of the sensory centres. Renzi considered this organ the nervous centre by which we perceive the reality of the external world, and direct and fix our senses on the things round us. Gall, and later Broussais, and others, held that this organ presided over the instinct of reproduction, or the propensity to love; while Carus regarded it as the seat of the will also. Rolando looked on it as the source of origin of all movements. Jessen adduced arguments in favour of its being the central organ of feeling, or of the soul, and the principal seat of the sensations." It is plain, from this list, that physiology had become obscured by fanciful notions of no practical value. If a better understanding of the nervous system could have been got without experiments on animals, why had men to wait so long for it? The Italian anatomists had long ago given them all the anatomy that was needed to make a beginning; the hospitals, and practice, had given them many hundred years of clinical facts; nervous diseases and head injuries were common enough in the Middle Ages; and by the time of Ambroise Paré, if not before, _post-mortem_ examinations were allowed. The one thing wanted was the experimental method; and, for want of it, the science of the nervous system stood still. Experiments had been made; but the steady, general, unbiassed use of this method had been lost sight of, and men were more occupied with logic and with philosophy. Then, in 1811, came Sir Charles Bell's work. If any one would see how great was the need of experiments on animals for the interpretation of the nervous system, let him contrast the physiology of the eighteenth century with that one experiment by Bell which enabled him to say, "I now saw the meaning of the double connection of the nerves with the spinal marrow." It is true that this method is but a part of the science of medicine; that experiment and experience ought to go together like the convexity and the concavity of a curve. But it is true also that men owe their deliverance from ignorance about the nervous system more to experiments on animals than to any other method of observing facts. 1. _Sir Charles Bell_ (1778-1842) The great authority of Sir Charles Bell has been quoted a thousand times against all experiments on animals:-- "Experiments have never been the means of discovery; and a survey of what has been attempted of late years in physiology, will prove that the opening of living animals has done more to perpetuate error than to confirm the just views taken from the study of anatomy and natural motions." He wrote, of course, in the days before bacteriology, before anæsthetics; he had in his mind neither inoculations, nor any observations made under chloroform or ether, but just "the opening of living animals." He had also in his mind, and always in it, a great dislike against the school of Magendie. Let all that pass; our only concern here is to know whether these words are true of his own work. They occur in a paper, _On the Motions of the Eye, in Illustration of the Uses of the Muscles and Nerves of the Orbit_; communicated by Sir Humphry Davy to the Royal Society, and read March 20, 1823.[6] This essay was one of a series of papers on the nervous system, presented to the Royal Society during the years 1821-1829. In 1830, having already published four of these papers under the title, _The Exposition of the Nervous System_, Bell published all six of them, under the title, _The Nervous System of the Human Body_. [6] This paper includes an _Experimental Enquiry into the Action of these Muscles_, giving an account of an experiment on the eye. In his Preface to this book (1830) he quotes the earliest of all his printed writings on the nervous system, a pamphlet, printed in 1811, under the title, _An Idea of a New Anatomy of the Brain, Submitted for the Observation of the Authors Friends_. We have therefore two statements of his work, one in 1811, the other in 1823 and 1830. The first of them was written when his work was still new before his eyes. Those who say that experiments did not help Bell in his great discovery--the difference between the anterior and the posterior nerve-roots--appeal to certain passages in the 1830 volume:-- "In a foreign review of my former papers, the results have been considered as a further proof in favour of experiments. They are, on the contrary, deductions from anatomy; and I have had recourse to experiments, not to form my own opinions, but to impress them upon others. It must be my apology that my utmost efforts of persuasion were lost, while I urged my statements on the grounds of anatomy alone. I have made few experiments; they have been simple and easily performed, and I hope are decisive.... "My conceptions of this matter arose by inference from the anatomical structure; so that the few experiments which have been made were directed only to the verification of the fundamental principles on which the system is established." If it were not for the 1811 pamphlet, the opponents of all experiments on animals might claim Sir Charles Bell on their side. But while his work was still a new thing, he spoke in another way of it:-- "I found that injury done to the anterior portion of the spinal marrow convulsed the animal more certainly than injury to the posterior portion; but I found it difficult to make the experiment without injuring both portions. "Next, considering that the spinal nerves have a double root, and being of opinion that the properties of the nerves are derived from their connections with the parts of the brain, _I thought that I had an opportunity of putting my opinion to the test of experiment, and of proving at the same time_ that nerves of different endowments were in the same cord (nerve-trunk) and held together by the same sheath. "On laying bare the roots of the spinal nerves, I found that I could cut across the posterior fasciculus of nerves, which took its origin from the posterior portion of the spinal marrow, without convulsing the muscles of the back; but that on touching the anterior fasciculus with the point of the knife, the muscles of the back were immediately convulsed. "_Such were my reasons for concluding_ that the cerebrum and cerebellum were parts distinct in function, and that every nerve possessing a double function obtained that by having a double root. _I now saw the meaning_ of the double connection of the nerves with the spinal marrow; and also the cause of that seeming intricacy in the connections of nerves throughout their course, which were not double at their origins." It is impossible to reconcile the 1830 sentences with this vivid personal account of himself; _I had an opportunity of putting my opinion to the test of experiment ... an opportunity of proving ... Such were my reasons for concluding ... I now saw...._ It is just what all men of science say of their experiments: the very phrase of Archimedes, and Asellius, and de Graaf. If Sir Charles Bell had been working at the facts of chemistry or of botany, who would have doubted the meaning of these words? This same inconsistency of sentences occurs elsewhere in his _Nervous System of the Human Body_. In one place he says that he has made few experiments: _They have been simple, and easily performed, and I hope are decisive._ In another he says: "_After making several experiments on the cerebrum and cerebellum, I laid the question of their functions entirely aside_, and confined myself to the investigation of the spinal marrow and the nerves; _a subject which I found more within my power_, and which forms the substance of the present volume." Next, take his account of the cranial nerves:-- "It was necessary to know, in the first place, whether the phenomena exhibited on injuring the separate roots corresponded with what was suggested by their anatomy.... "Here a difficulty arose. An opinion prevailed that ganglions were intended to cut off sensation; and every one of these nerves, which I supposed were the instruments of sensation, have ganglions on their roots. Some very decided experiment was necessary to overturn this dogma. (Account of the experiment.) By pursuing the inquiry, it was found that a ganglionic nerve is the sole organ of sensation in the head and face: ganglions were therefore no hindrance to sensation; and thus my opinion was confirmed.... _It now became obvious_ why the third, sixth, and ninth nerves of the encephalon were single nerves in their roots.... "Observing that there was a portion of the fifth nerve which did not enter the ganglion of that nerve, and being assured of the fact by the concurring testimony of anatomists, I conceived that the fifth nerve was in fact the uppermost nerve of the spine.... This opinion was confirmed by experiment.... (Account of an experiment on the dead body.) On dividing the root of the nerve in a living animal, the jaw fell relaxed. Thus its functions are no longer matter of doubt: it is at once a muscular nerve and a nerve of sensibility. And thus the opinion is confirmed, that the fifth nerve is to the head what the spinal nerves are to the other parts of the body, in respect to sensation and volition." The value of the experimental method could hardly be stated in more emphatic words. He supposed something, conceived it, had an opinion about it. Anatomy had suggested something to him. He put his opinion to the test of phenomena, that is to say, to the test of visible facts; and then his opinion was confirmed. As with the spinal nerve-roots, so with the fifth cranial nerve--his work was successful, because he followed the way of experiment. He was by nature of a most complex and sensitive temperament, full of contrary forces--one man in 1811, another in 1830. In 1811 he wrote, _I now saw the meaning of the double connection of the nerves_; in 1830 he had come to hate the _stupid sterile materialism_ of the French school: he beheld anatomy falling behind physiology, and his Windmill Street school perishing to make way for the Hospital schools and for the University of London. He was before everything else a great anatomist: he stood up for the honour of anatomy against the new physiology, and for the honour of the Monroes and the Hunters against Magendie: he hated the notion that any man should proceed to experiments on function till the very last secrets had been got out of structure. He died a few years afterward. The 1830 writings are his last stand for the defence of his country, his school, and his beloved anatomy, against the methods of Magendie; who said of himself, "I am a mere street scavenger, _chiffonier_, of science. With my hook in my hand and my basket on my back, I go about the streets of science, collecting what I find." This open conflict between Bell's first and last thoughts is a part of his character: he was brilliant, impulsive, changeable, inconsistent; and, what is more important, his honour kept him from trying to evade this trumpery charge of inconsistency; and he reprinted the 1811 Preface in the book that he published in 1830. Doubtless he would have picked his words more carefully if he had foreseen that one of the 1830 sentences would be wrested out of its place in his life's work, and used as false evidence against the very method that he followed. His observations on the cranial nerves brought about an immediate change in the practice of surgery:-- "Up to the time that Sir Charles Bell made his experiments on the nerves of the face, it was the common custom of surgeons to divide the facial nerve for the relief of neuralgia, _tic douleureux_; whereas it exercises, and was proved by Sir Charles Bell to exercise, no influence over sensation, and its division consequently for the relief of pain was a useless operation." (Sir J. Erichsen.) The relation of Magendie's work on the nerve-roots to Bell's work need not be considered here. The exact dates of Bell's observations are given by one of his pupils in the Preface to the 1830 volume. Magendie finally proved the sensory nature of the posterior nerve-roots: "The exact and full proof which he brought forward of the truth which Charles Bell had divined rather than demonstrated, that the anterior and posterior roots of spinal nerves have essentially different functions--a truth which is the very foundation of the physiology of the nervous system--is enough by itself to mark him as a great physiologist." (Sir M. Foster, _loc. cit._) 2. _Marshall Hall_ (1790-1857) Reflex action had been studied long before the time of Marshall Hall. The Hon. Robert Boyle (1663) had observed the movements and actions of decapitated vipers, flies, silkworms, and butterflies. Similar observations were made on frogs, eels, and other lower animals, by Redi, Woodward, Stuart, Le Gallois, and Sir Gilbert Blane. According to Richet, it was Willis who first gave the name _reflex_ to these movements. It cannot be said that these first studies of reflex action did much for physiology. But the following translation from Prochaska (1800) shows how they cleared the way for Marshall Hall's work, by the proof that they gave of the liberation of nervous energy in the spinal cord:-- "These movements of animals after decapitation must needs be by consent and commerce betwixt the spinal nerves. For a decapitated frog, if it be pricked, not only draws away the part that is pricked, but also creeps and jumps; which cannot happen but by consent betwixt the sensory nerves and the motor nerves. The seat of which consent must needs be in the spinal cord, the only remaining portion of the sensorium. _And this reflexion of sensory impressions into motor impressions is not accomplished in obedience to physical laws alone--wherein the angle of reflexion is equal to the angle of incidence, and reaction to action--but it follows special laws as it were written by Nature on the spinal cord, which we can know only by their effects, but cannot fathom with the understanding._ But the general law, whereby the sensorium reflects sensory impressions into motor impressions, is the preservation of ourselves." It was not possible, in 1800, to go further, or to put the facts of reflex action more clearly: but this fine sentence gives no hint of the truth that guided Marshall Hall--that the "consent and commerce" of reflex action are to be found at definite points or levels in the spinal cord; that the cord no more "works as a whole" than the brain. The greatness of Marshall Hall's work lies in his recognition of the divisional action of the cord: he proved the existence of definite centres in it, he discovered the facts of spinal localisation, and thus foreshadowed the discovery of cerebral localisation. In his earlier writings (1823-33) he showed how the movements of the trunk and of the limbs are only one sort of reflex action; how the larynx, the pharynx, and the sphincter muscles, all act by the "consent and commerce" of the spinal cord. Later, in 1837, he demonstrated the course of nerve-impulses along the cord from one level to another, the results of direct stimulation of the cord, and other facts of spinal localisation. He noted the different effects of opium and of strychnine on reflex action; and he extended the doctrines of reflex action beyond physiology to the convulsive movements of the body in certain diseases. 3. _Flourens_ (1794-1867) Beside his work on the nervous system, Flourens studied the periosteal growth of bone, and the action of chloroform;[7] but he is best known by his experiments on the respiratory centre and the cerebellum. The men who interpreted the nervous system followed the anatomical course of that system: first the nerve-roots, then the cord, then the medulla oblongata and the cerebellum, and last the cerebral hemispheres; a steady upward advance, from the observation of decapitated insects to the localisation of centres in the human brain. Flourens, by his work on the medulla oblongata, localised the respiratory centre, the nerve-cells for the reflex movements of respiration:-- "M. Flourens a circonscrit ce centre avec une scrupuleuse précision, et lui a donné le nom de noeud vital" (Cl. Bernard.) [7] When Flourens died, Claude Bernard was appointed to his place in the French Academy; and, in the _Discours de Reception_ (May 27, 1869), said, "It is twenty-two years since the discovery of anæsthesia by ether came to us from the New World, and spread rapidly over Europe. M. Flourens was the first man who showed that chloroform is more active than ether." Afterward came the discovery of cardiac and other centres in the same portion of the nervous system. Flourens also showed that the cerebellum is concerned with the equilibration of the body, and with the coordination of muscular movements; that an animal, a few days old, deprived of sensation and consciousness by removal of the cerebral hemispheres, was yet able to stand and move forward, but, when the cerebellum was removed, its muscles lost all co-ordinate action. (_Recherches Expérimentales_, Paris, 1842.) And from his work, and the work of those who followed him, on the semicircular canals of the internal ear, came the evidence that these minute structures are the terminal organs of equilibration: that as the special senses have their terminal apparatus and their central apparatus, so the semicircular canals and the cerebellum are the terminal apparatus and the central apparatus of the sense of equilibrium. 4. _Claude Bernard_ (1813-1878) The discovery of the vaso-motor nerves, and of the control of the nervous system over the calibre of the arteries, was made by Claude Bernard at the outset of his work on the influence of the nervous system on the temperature.[8] The evidence of Professor Sharpey before the Royal Commission of 1875 shows how things had been misjudged, before Bernard's time, in the light of "views taken from the Study of Anatomy and Natural Motions":-- "I remember that Sir Charles Bell gave the increased size of the vessels in blushing, and their fulness of blood, as an example of the increased action of the arteries in driving on the blood. It turns out to be just the reverse, inasmuch as it is owing to a paralysis of the nerves governing the muscular coats of the arteries." [8] A full account of this discovery, and of its relation to the experiments of Brown Séquard, Waller, and Budge, is given by Sir Michael Foster in his life of Claude Bernard; and the question of priority between Bernard and Brown Séquard need not be considered here, for the experimental method was the only way open to either of them. For an account of the work done, before Bernard, in this field of physiology, see Prof. Stirling's admirable and learned monograph, _Some Apostles of Physiology_ (Waterlow & Sons, London, 1902), p. 104. Claude Bernard's first account of his work was communicated to the Société de Biologie in December 1851. The following description is taken from his _Leçons de Physiologie Opératoire_:-- "I will remind you how I was led to the discovery of the vaso-motor nerves. Starting from the clinical observation, made long ago, that in paralysed limbs you find at one time an increase of cold, and at another an increase of heat, I thought this contradiction might be explained by supposing that, side by side with the general action of the nervous system, the sympathetic nerve might have the function of presiding over the production of heat; that is to say, that in the case where the paralysed limb was chilled, I supposed the sympathetic nerve to be paralysed, as well as the motor nerves; while in the paralysed limbs that were not chilled, the sympathetic nerve had retained its function, the systemic nerves alone having been attacked. "This was a theory, that is to say, an idea leading me to make experiments; and for these experiments I must find a sympathetic nerve-trunk of sufficient size, going to some organ that was easy to observe, and must divide this trunk to see what would happen to the heat-supply of the organ. You know that the rabbit's ear, and the cervical sympathetic nerve of this animal, offered us the required conditions. So I divided the nerve; and immediately my experiment gave the lie direct to my theory--_Je coupai donc ce filet et aussitôt l'expérience donna à mon hypothèse le plus éclatant démenti_. I had thought that the section of the nerve would suppress the function of nutrition, of calorification, over which the sympathetic system had been supposed to preside, and would cause the hollow of the ear to become chilled; and here was just the opposite, a very warm ear, with great dilatation of its vessels. "I need not remind you how I made haste to abandon my first theory, and gave myself to the study of this new state of things. And you know that here was the starting-point of all my researches into the vaso-motor and thermic system; and the study of this subject is become one of the richest fields of experimental physiology." Waller, in 1853, studied the vaso-motor centre in the spinal cord; and Schiff, in 1856, found evidence of the existence of two kinds of vaso-motor nerves--those that constrict the vessels, and those that dilate them. This view was finally established in 1858 by Claude Bernard's experiments on the chorda tympani and the submaxillary gland. The _Leçons de Physiologie Opératoire_ were published in 1879. Twenty years later, Sir Michael Foster says of Bernard's work:-- "It is almost impossible to exaggerate the importance of these labours of Bernard on the vaso-motor nerves, since it is almost impossible to exaggerate the influence which our knowledge of the vaso-motor system, springing as it does from Bernard's researches as from its fount and origin, has exerted, is exerting, and in widening measure will continue to exert, on all our physiological and pathological conceptions, on medical practice, and on the conduct of human life. There is hardly a physiological discussion of any width in which we do not sooner or later come on vaso-motor questions. Whatever part of physiology we touch, be it the work done by a muscle, be it the various kinds of secretive labour, be it the insurance of the brain's well-being in the midst of the hydrostatic vicissitudes to which the changes of daily life subject it, be it that maintenance of bodily temperature which is a condition of the body's activity; in all these, as in many other things, we find vaso-motor factors intervening. And if, passing the insecure and wavering line which parts health from illness, we find ourselves dealing with inflammation, or with fever, or with any of the disordered physiological processes which constitute disease, we shall find, whatever be the tissue specially affected by the morbid conditions, that vaso-motor influences have to be taken into account. The idea of vaso-motor action is woven as a dominant thread into all the physiological and pathological doctrines of to-day; attempt to draw out that thread, and all that would be left would appear as a tangled heap." 5. _Cerebral Localisation_ Finally, moving upward along the anatomy of the nervous system, physiology came to study the motor-centres and special sense-centres of the cerebral hemispheres. The year 1861 may fairly be said to mark the beginning of the discovery of these centres, when Broca, at a meeting of the Anthropological Society of Paris, heard Aubertin's paper on the connection between the frontal convolutions and the faculty of speech. But, of course, some sort of belief in cerebral localisation had been in the air long before Broca's time. Willis (1621-1675), who was contemporary with Sir Isaac Newton, had written of the brain as though its convolutions, or "cranklings" as he called them, showed that its work was departmental:-- "As the animal spirits for the various acts of imagination and memory ought to be moved within certain and distinct limits, or bounded places, and these motions to be often iterated or repeated through the same tracts or paths, for that reason these manifold convolutions and infoldings of the brain are required for these divers manners of ordinations of the animal spirits--to wit, that in these cells or storehouses, severally placed, might be kept the species of sensitive things, and as occasion serves, may be taken from thence."[9] [9] For an account of Willis' work on the nervous system, see Sir Victor Horsley's _Fullerian Lectures_, 1891. Willis was the first, or one of the first, to recognise the fact that the cerebral ventricles are nothing more than lymph-cavities. And Gall, a century after Willis, had collected and published, in support of his system of phrenology, many cases and _post-mortem_ examinations showing the differentiation of the work of the brain. Gall is a warning for all time against the dangers of deduction; he had but one idea, and he drove it to death; but the clinical and pathological facts which he amassed, in the hope of establishing a set of doctrines out of all relation to facts, are as true now as ever; and, if he had been content to go the way of induction, and to set himself to the accumulation of facts, he might have become a great physiologist. In his knowledge of the anatomy of the brain, and in the dissection of the brain, he was far ahead of the men of his time; but he followed his own imaginings, and left nothing that could last, except those cases and pathological instances that are buried in the ruins of his system. But there they are, and are still of value. For example, Gall's case of loss of speech, after an injury involving the speech-centres, ought to have commanded the attention of all physiologists: but it came to nothing, because he used it to support his doctrine of organs and bumps, and it shared the fate of that doctrine. Phrenology is gone past recall; it died of that congenital disease, the deductive fallacy; but there was a time when it might have been turned to the service of science. The excitement that Gall aroused by the spread of his ideas shows that some belief in cerebral centres was waiting for development. All men are by nature phrenologists; the commonplace excuses that are offered for lapses of memory, venial offences, and inherited weaknesses, all appeal to the comfortable notion that the offender is not wholly perverted, and that some very small and strictly localised group of cells is at fault. And it is probable that the physiology of the central nervous system, with its present strong tendency toward psychology, will some day be back, at a far higher level, above the point where phrenology went wrong. As Mme. de Staël said, _L'esprit humain fait progrès toujours, mais c'est progrès en spirale_. But the question, whether the general desire for a rational system of psychology will ever commend itself to physiology, belongs to the future. All that is of present concern is the steady, continuous, and successful advance, by the way of induction, and by the help of experiments on animals, toward a clear and accurate statement of the departmental work of the brain. It is one of many instances how science and practice work together, that the modern study of these centres began not in experiment but in experience. The first centres that were thus studied were the speech-centres; and the observation of them arose out of the cases recorded by Bouillard in 1825, and Dax in 1836. Clinical observation, and _post-mortem_ examination, found the speech-centres; physiological experiments had nothing to do with it; and phrenology had, as it were, found them, and then lost them. But at once, so soon as practice gave the word to science, physiology set to work. These clinical facts had been there all the time; loss of speech had gone with disease or injury of "Broca's convolution" ever since man had been on the earth, and nobody had seen the significance of this sequence. Then, after 1861, everything was changed; and in a few years physiology had mapped out a large part of the surface of the brain, and had charted the motor-centres. The story of Broca's convolution is told in Hamilton's _Text-Book of Pathology_:-- "In 1825, Bouillard collected a series of cases to show that the faculty of speech resided in the frontal lobes. In the year 1836 M. Dax, in a paper read to the Medical Congress of Montpellier, stated as a result of his researches that, where speech was lost from cerebral causes, he believed the lesion was invariably found in the left cerebral hemisphere, and that the accompanying paralysis of the right side of the body is consequent upon this. This paper for long lay buried in the annals of medical literature, but was unearthed years afterwards by his son, and presented to the French Academy. Bouillard's views were also disinterred by Aubertin, and in the year 1861 were brought by him before the notice of the Anthropological Society of Paris. Broca, who was present at the meeting, had a patient under his care at the time who had been aphasic (without power of speech) for twenty-one years, and who was in an almost moribund state. The autopsy proved of great interest, as it was found that the lesion was confined to the left side of the brain, and to what we now call the third frontal convolution. Broca was struck with the coincidence; and when a similar case came under his care afterwards, unaware of what had been done by Dax, he postulated the conclusion that the integrity of the third frontal convolution, and perhaps also part of the second, is essential to speech. In a subsequent series of fifteen typical cases examined, it was found that the lesion had destroyed, among other parts, the posterior part of the third frontal in fourteen. In the fifteenth case the destruction had taken place in the island of Reil and the temporal lobe." After 1861, physiology took the lead, and kept it. But, through all the work, science and practice have been held together; the facts of experimental physiology have been and are tested, every inch of the way, by the facts of medicine, surgery, and pathology. The infinite minuteness and complexity of the investigation, and its innumerable side-issues, are past all telling. They who are doing the work, in science and in practice, have always had in their thoughts the fear of fallacies in the interpretation of these highest forms of life. Sir William Gowers, fourteen years ago, wrote as follows of the earlier workers:-- "Doubt was formerly entertained as to the existence of differentiation of function in different parts of the cortex, but recent researches have established the existence of a differentiation which has almost revolutionised cerebral physiology, and has vastly extended the range of cerebral diagnosis. The first step of the new discovery was constituted by the clinical and pathological observations of Hughlings Jackson, which suggested the existence, on each side of the fissure of Rolando, of special centres for the movements of the leg, arm, and face. These observations led to the experiments of Ferner, which resulted in the demonstration of the existence in the cortex of the lower animals of well-defined regions, stimulation of which caused separate movements, or evidence of special sense excitation, while the destruction of the same parts caused indications of a loss of the corresponding function. Hence he came to the conclusion that these regions constitute actual motor and sensory centres. Ferrier had, however, been anticipated in many of these results by two German experimenters, Fritsch and Hitzig, whose results, differing a little in detail, correspond closely in their general significance. Many other investigations of the same character have since been made, of which those of Munk are especially important. The original observations of Hughlings Jackson left little doubt that the general facts, learned from experiments on animals, are true of man; and this conclusion has been to a large extent confirmed by pathological and clinical observations directed to the verification on man of the pathological results. To this verification the labours of Charcot and his coadjutors have largely contributed. But the verification has already made it probable that some differences exist between the brain of man and that of higher animals (even of monkeys), and that the conclusions from the latter cannot be simply transferred to the former." Many and great difficulties, beyond this danger of the fallacy of "simple transference," beset every step of the work: it required the right use of the most delicate and susceptible instruments and tests, and the right understanding of anatomy, microscopic anatomy, comparative anatomy, organic chemistry, electricity, and physics: every moment of advance must be guarded, every word must be weighed. Among the earlier difficulties, was the failure of almost all the physiologists, before Hitzig, to produce muscular action by excitation of the cerebral cortex. Longet, Magendie, Flourens, Matteuci, Van Deen, Weber, Budge, and Schiff, had all failed. Hitzig (_Untersuchungen über das Gehirn_, Berlin, 1874) had observed, in man, that it was easy to produce movements of the eyes by the passage of the constant current through the occipital region.[10] Taking this fact for a starting-point, he used a very low current, and thereby succeeded in producing certain definite muscular movements by stimulation of the cortex in animals. Of Hitzig's work, Sir Victor Horsley says:-- "It was not till 1870 that the next absolute proof (after Bell's work in 1813) was obtained of the localisation of function, so far as the highest centres of the nervous system were concerned. In that year Fritsch and Hitzig discovered that electrical excitation, with minimal stimuli, of various points of the cortex, caused those storehouses, of which Willis spoke, to discharge, and to reveal their function by the precise limitation of the groups of muscles which they were able to throw into action. These researches were abundantly confirmed and greatly extended by Professor Ferrier, and thus has been constructed in the history of this subject the most recent great platform or stage of permanent advance."[11] [10] That the surface of the brain is not sensitive of such stimulation, that it does not perceive its own substance, was known to Aristotle. The fact is so familiar that there is no need to quote evidence of it, beyond that of Sir Charles Bell: "I have had my finger deep in the anterior lobes of the brain, when the patient, being at the time acutely sensible, and capable of expressing himself, complained only of the integument." [11] Horsley, _Fullerian Lectures_, 1891, _loc. cit._ The thirty years since Hitzig's work cannot be put here, for they would take a volume to themselves. There have been differences of interpretation of this or that fact, diversities of results, and problems too hard to solve, and other difficulties, such as befall all the natural sciences; but these imperfections amount to very little, when the whole result comes to be reckoned. The marvel is that the work is so nearly perfect, seeing its immeasurable complexity. Let any man, who has but touched the study of physiology, consider what is involved in even the most superficial observation of the simplest facts of the nervous system: for instance, the ordinary nerve-muscle preparation that is taught to every medical student, or the microscopic structure of the spinal cord, or the Wallerian method. Or let him consider how the physiology of the nervous system has been founded on the lower forms of life: the work of Romanes and others on the Medusa and the Echinodermata, and Huxley's work in biology, and the endless chain of forces that are alike in man and in jelly-fishes. Then let him try to estimate the output of hard thinking, for the advance from lower to higher structures, and up to man; the vigilant criticism of all theories and foregone conclusions, the incessant self-judgment and wearisome doubts and disputes all the way, elusiveness of facts, and vagueness of words. And the results thus wrung out of science had still to be stated in terms of practice, and tested by the facts of medicine, surgery, and pathology, and used in every hospital in the civilised world, not only for the saving of life, but also for the diagnosis and medical or surgical treatment of innumerable varieties of disease or injury of the brain, the cord, or the nerves. Sir Michael Foster, in a short summary of the problems of physiology, puts clearly these consummate difficulties of the physiology of the nervous system:-- "In the first place there are what may be called general problems, such as, How the food, after its preparation and elaboration into blood, is built up into the living substance of the several tissues? How the living substance breaks down into the dead waste? How the building up and breaking down differ in the different tissues in such a way that energy is set free in different modes, the muscular tissue contracting, the nervous tissue thrilling with a nervous impulse, the secreting tissue doing chemical work, and the like? To these general questions the answers which we can at present give can hardly be called answers at all. "In the second place there are what may be called special problems, such as, What are the various steps by which the blood is kept replenished with food and oxygen, and kept free from an accumulation of water; and how is the activity of the digestive, respiratory, and excretory organs, which effect this, regulated and adapted to the stress of circumstances? What are the details of the vascular mechanism by which each and every tissue is for ever bathed with fresh blood, and how is that working delicately adapted to all the varied changes of the body? And, _compared with which all other problems are insignificant and preparatory only_, how do nervous impulses so flit to and fro within the nervous system as to issue in the movements which make up what we sometimes call the life of man?" The physiology of the nervous system is wrought to finer issues now than in the time of Bell and Magendie; and this generation of students may live to see the present facts and methods of cerebral localisation as the mere rudiments or elements of science. Happily for mankind, science has already so far elucidated them that they have done good service for the diagnosis and treatment of disease, and for the saving of lives. * * * * * Some examples have been given, in the foregoing chapters, of the value of physiological experiments on animals. It would be easy to lengthen the list, for there is no general subject in all physiology that does not owe something to this method: as Mr. Darwin said, in his evidence before the Royal Commission of 1875, "I am fully convinced that physiology can progress only by the aid of experiments on living animals. I cannot think of any one step which has been made in physiology without that aid." Many examples have been left out altogether--the work of Boyle, Hunter, Lavoisier, Haldane, Despretz, and Regnault, on animal heat and on respiration; of Petit, Dupuy, Breschet, and Reid, on the sympathetic system; of Galvani, Volta, Haller, du Bois-Reymond, and Pflüger, on muscular contractility: nothing has been said of the work lately done on the suprarenal glands and "adrenalin," and on the blood-pressure in its relation to secretion. For the most part, only those examples have been taken that occur far back in the history of physiology: more has been said about the past than about the present. First, because it was necessary to put an end to the false statements that are made, by those who are opposed to all experiments on animals, about the work done in the past. Next, because the abstruse details of physiology, in the present, are not intelligible for general reading. Next, because it is impossible now to isolate physiology, or to say what belongs to physiology alone, to have back the simpler problems of the past, to discover the circulation of the blood twice. But the experimental method, alike in the past and in the present, has been the chief way of advance. And if a forecast may be made without offence, it is certain that the work of physiology, as in the past and the present, so in the near future, will exercise a profound influence for good on medical and surgical treatment. Among the subjects that especially occupy physiologists now are, the more exact localisation and interpretation of the special sense-centres, and the better knowledge of the internal secretions and chemical influences of the glands and tissues of the body. It would be hard to find two fields of work more sure to favour the growth of the _arbor vitæ_ side by side with the _arbor scientiæ_. But the last word here must be said by a physiologist of the very highest authority, Professor Starling. He has kindly given me, for this edition, the following note:-- "Among the researches of the last thirty years, those bearing on the _Circulation of the Blood_ must take an important place, both for their physiological interest and for the weighty influence they have exerted on our knowledge and treatment of disorders of the vascular system, such as heart disease. We have learned to measure accurately the work done by the great heart-pump; and by studying the manner in which this work is affected by different conditions, we are enabled to increase or diminish it, according to the needs of the organ. Experiments in what is often regarded as the most transcendental department of physiology--_i.e._ that which treats of muscle and nerve--have thrown light on the wonderful process of 'compensation,' by which a diseased heart is able to keep up a normal circulation. "_Vaso-motor System._--Largely by the labours of British physiologists, the exquisite control exercised by the nervous system over every blood-vessel in the body has been brought to light, the paths tracked out, and the mechanisms elucidated, by means of which the circulation through each part of the body is subordinated to the needs of the whole. Since the chief vaso-motor nerves take their course through the sympathetic system, the researches on their distribution have led to the mapping out of the whole of this system, and to an accurate knowledge of its functions. We are now acquainted with the course, to all parts of the body, of the nerves which not only determine the changes in the calibre of the blood-vessels, but affect also the secretion of sweat and the erection of the hairs. Incidentally, the mapping out of these nerves, in the hands of Mackenzie, Head, and others, has led to more power of localising the seat of visceral disease. "_Digestion._--Our knowledge of the processes of digestion has of late years received a great accession by the work of Professor Pawlow, of St. Petersburg. His success is largely due to his recognition of the importance of keeping his experimental animals under the most normal conditions possible, and of studying the different parts of the alimentary tract in animals which were not anæsthetised, but which were free from any pain or even discomfort, either of which conditions materially interferes with the activity of the digestive glands. He therefore established in dogs fistulæ in chosen portions of the alimentary canal, analogous to the fistula which accident rendered so valuable in the case of Alexis St. Martin. Not only has the knowledge thus gained enabled the physician to understand the sequel of events in disordered digestion, but the success of the operative measures undertaken by physiologists for the elucidation of their science has emboldened surgeons to attack disease in the most various parts of the alimentary canal. "Renewed study of the secretion of pancreatic juice evoked by the passage of the acid digestive products from the stomach into the small intestine, which had been described by Pawlow, has resulted in the discovery of a new class of chemical agents, which act as special messengers from one part of the body to another, and exercise an important function in determining the action of all parts to one common end. "_Respiration._--The investigation of the chemical properties of the colouring matter of blood, and of its compound with carbon monoxide, has resulted, in the hands of Dr. Haldane, in the laying down of measures for the prevention of accidents from choke-damp or after-damp in mines. The same investigation has resulted in the discovery of a method of determining the total amount of blood circulating in the body of a living man. The application of this method has already added largely to our knowledge of the pathology of different forms of anæmia, as well as of the conditions obtaining in heart disease. Experiments by Hill and others on the physiological effects of compressed air have shown the precautions which should be observed in all diving operations. A proper appreciation of these results by diving-engineers would not only entirely obviate the cases of 'caisson disease,' but would enable diving to be carried on safely to a greater depth than has hitherto been attempted. "It is impossible, however, to enumerate all the physiological gains of the last twenty or thirty years, or to point out their manifold applications in the cure and prevention of disease. The full control of the processes of disease, which is the goal of the physician and the surgeon, can only be attained through an accurate knowledge of the conditions governing the functions of the healthy body. The foundation of medicine and surgery is physiology: and it is only on living animals that the processes of life can be investigated." PART II EXPERIMENTS IN PATHOLOGY, MATERIA MEDICA, AND THERAPEUTICS I INFLAMMATION, SUPPURATION, AND BLOOD-POISONING Pathology, the study of the causes and products of diseases, is a younger science than physiology: the use of the microscope was the beginning of pathology; and the microscope, even so late as sixty years ago, was very different to the microscope now. The great pathologists of that time had not the lenses, microtomes, and reagents that are now in daily employment; they knew nothing of the present methods of section-cutting and differential staining. But the publication in 1839 of Schwann's cell-theory marks the rise of modern pathology. In 1843, Darwin wrote his first draft of the doctrine of the origin of species; and Pasteur, that year, was in for his examination at the École Normale. The work of Schwann, Virchow, and Pasteur had such profound influences on science that the span of sixty years seems to cover the modern development of pathology: and this span of years is marked, half-way, by the rise of bacteriology. In 1875, when the Royal Commission on Experiments on Animals was held in London, the evidence was concerned practically with physiology alone: very little was said about pathology, and of bacteriology hardly a word. The witnesses say that they "believe they are beginning to get an idea" of the true nature of tubercle: and the evidence as to the nature of anthrax, given by Sir John Simon, reads now like a very old prophecy:-- "We are going through a progressive work that has many stages, and are now getting more precise knowledge of the contagium. By these experiments on sheep it has been made quite clear that the contagium of sheep-pox is _something of which the habits can be studied: as the habits of a fern or a moss can be studied: and we look forward to opportunities of thus studying the contagium outside the body which it infects. This is not a thing to be done in a day, or perhaps in ten years, but must extend over a long period of time._ Dr. Klein's present paper represents one very important stage of a vast special study. He gives the identification of the contagium as _something which he has studied to the end in the infected body, and which can now in a future stage be studied outside the body_." Thirty years ago, there was no bacteriology, in the present sense of the word: and now the "habits" of these "contagia" have been studied, outside and inside the body, with amazing accuracy. It has been proved, past all possibility of doubt, that the pathogenic bacteria are the cause of infective diseases; they have fulfilled Koch's postulates--that they should be found in the diseased tissues, be cultivated outside the body, reproduce the same disease in animals, and be found again in the tissues of those animals. By an immeasurable amount of hard work crowded into a few years, this New World of bacteriology has been subdued. The Royal Commissioners of 1875, speaking of physiological experiments only, said, "It would require a voluminous treatise to exhibit in a consecutive statement the benefits that medicine and surgery have derived from these discoveries." If physiology in 1875 required a treatise, bacteriology in 1906 requires a library: and it is impossible here to give more than the faintest outline of some of the work that has been done. But all pathology is not bacteriology; and it would take a treatise of prodigious length to set forth the work of modern pathology in the years before anything was known of bacteria. The microscopic structure of tumours and of all forms of malignant disease, the nature of amyloid, fatty, and other degenerative changes, and the chief facts of general pathology--hypertrophy and atrophy, necrosis, gangrene, embolism, and many more--all these subjects were studied to good purpose, before bacteriology. Above all, men were occupied in the study of inflammation under the microscope. It was this use of the microscope that revolutionised pathology; especially, it made visible the whole process of inflammation, the most minute changes in the affected tissues, the slowing and arrest of the blood in the capillaries, the choking-up of the stream, and the escape of blood-cells out of the capillaries into the tissues. Everything had been made ready for the fuller interpretation that was coming from bacteriology: the old naked-eye descriptions of inflammation were left behind; men set aside the definition of Celsus, that it was _rubor et tumor cum colore et dolore_--words that sound like Molière's jest about the _vis dormitiva_ of opium--they watched inflammation under the microscope, in such transparent structures as the frog's web and mesentery, the bat's wing, and the tadpole's tail. It was thus that Wharton Jones discovered the rhythmical contraction of the veins in the bat's wing. The discovery of the escape of the white blood-cells, _diapedesis_, through the walls of the capillaries, was made by Waller and Cohnheim. To those who are opposed to all experiments on animals, it may seem a very small thing that a blood-cell should be on one side or the other of a microscopic film in a tadpole's tail; but this _diapedesis_, the first move of the blood in its fight against disease, is now seen, in the light of Metschnikoff's work, as a fact of very great importance. The history of this transitional period, from the study of inflammation in transparent living tissues to the use, in surgery, of the facts of bacteriology, is told in Lord Lister's Huxley Lecture, October 1900. He describes how the foundations were laid in surgical pathology, by microscopical and experimental work on inflammation, coagulation, suppuration, and pyæmia, for bacteriology to build on: how his own share of the work began when he was house-surgeon to Sir John Erichsen at University College Hospital, and afterward to Mr. Syme in Edinburgh, and how it was continued through all his Edinburgh and Glasgow life:-- "After being appointed to the Chair of Surgery in the University of Glasgow, I became one of the surgeons to the Royal Infirmary of that city. Here I had, too, ample opportunities for studying hospital diseases, of which the most fearful was pyæmia. About this time I saw the opinion expressed by a high authority in pathology that the pus in a pyæmic vein was probably a collection of leucocytes. Facts such as those which I mentioned as having aroused my interest in my student days in a case of pyæmia, made such a view to me incredible; and I determined to ascertain, if possible, the real state of things by experiment.... "While these investigations into the nature of pyæmia were proceeding, I was doing my utmost against that deadly scourge. Professor Polli, of Milan, having recommended the internal administration of sulphite of potash on account of its antiputrescent properties, I gave that drug a very full trial as a prophylactic.... At the same time, I did my best, by local measures, to diminish the risk of communicating contagion from one wound to another. I freely employed antiseptic washes, and I had on the tables of my wards piles of clean towels to be used for drying my hands and those of my assistants after washing them, as I insisted should invariably be done in passing from one dressing to another. But all my efforts proved abortive; as I could hardly wonder when I believed, with chemists generally, that putrefaction was caused by the oxygen of the air. "It will thus be seen that I was prepared to welcome Pasteur's demonstration that putrefaction, like other true fermentations, is caused by microbes growing in the putrescible substance. Thus was presented a new problem: not to exclude oxygen from the wounds, which was impossible, but to protect them from the living causes of decomposition by means which should act with as little disturbance of the tissues as is consistent with the attainment of the essential object.... To apply that principle, so as to ensure the greatest safety with the least attendant disadvantage, has been my chief life-work."[12] [12] See also the admirable Life of Pasteur, by M. Valléry-Radot. Translation by Mrs. Devonshire, vol. ii. p. 20. And, of course, the application of that principle is not limited to the performance of the major operations of surgery. It is in daily use in every hospital, and in every practice all the world over, for the safe and quick healing of whole legions of injuries, "casualties," and minor operations. But what of Semmelweis, and his study of puerperal fever? Did he not, before Lord Lister, and without the help of experiments on animals, discover antiseptic surgery? His claim is urged by those who are opposed to all such experiments. And the answer is, that his work was lost just for want of experiments on animals. If he could have demonstrated, as Pasteur did, the living organism, the thing itself, there in the tissues of an infected rabbit, and in a test-tube, and under a microscope, he might have stopped the mouths of his adversaries. He could not. He could only demonstrate to them the fact that their patients died, and his patients lived: and that some sort of direct infection was the cause of the deaths. The tragedy of his life cannot be told too often, and may be told again here.[13] For want of the final proof that bacteriology, and the inoculation of animals, alone could give, he was unable to hold out against his enemies till Pasteur could rescue him. [13] This account of Semmelweis, reprinted by permission from the _Middlesex Hospital Journal_, is mostly taken from Dr. Theodore Duka's excellent paper on "Childbed Fever." (_Lancet_, 1886.) In 1846, when he was twenty-three years old, Ignaz Semmelweis was appointed assistant-professor in the maternity department of the huge general hospital of Vienna. For many years, the mortality in the lying-in wards had been about 1.25 per cent., and no more. Then, under a new professor, it had risen; and, for some years before Semmelweis came on the scene, it had been 5 per cent., or even 7 per cent. In October 1841, there had been an epidemic that had lasted till May 1843. In these twenty months, out of 5139 women delivered, 829 had died; that is to say, 16 per cent. There were two sets of wards in the maternity department. The one set may be called Clinique A, and the other Clinique B. For many years, the mortality had been the same in each. In 1841 a change was made: Clinique A was assigned to the teaching of students, and Clinique B to the teaching of midwives: and, so soon as this change had been made, the mortality in Clinique B became less, but the mortality in Clinique A did not. Commissions of inquiry were held, and in vain. It was suggested that the foreign students were somehow to blame, nobody knew why; and many of them were sent away. Still the deaths went on. Women admitted to Clinique A would go down on their knees and pray to be allowed to go home; almost every day the bell was heard ringing in the wards, for the administration of the Sacrament to a dying woman. People talked about atmospheric influences, and overcrowding, and the tainted air of old wards, and the power of the mind over the body: and Semmelweis set to work. He observed that cases of protracted labour in Clinique A died, almost all of them; but not in Clinique B. He observed also that cases of premature labour, nearly all of them, did well, whichever Clinique they were in; so did those women who were delivered before they came to the hospital, and were admitted after delivery. He observed also that a row of patients, lying side by side, would all be attacked at once in Clinique A; which never happened in Clinique B. He tried everything: he altered the details of treatment; he used various subterfuges to prevent one of the professors from examining serious cases; he enforced this or that rule in Clinique A, because it was the custom in Clinique B; he slaved away at the notes of the cases--and at last the truth came to him, by the death of one of his friends from a dissection-wound. He says, "My friend's fatal symptoms unveiled to my mind an identity with those which I had so often noticed at the deathbeds of puerperal cases." He saw now that the students, coming straight from the dissecting-rooms, had infected the patients during examination. In May 1847 he gave orders that every student, before examining, should thoroughly disinfect his hands. But, though he had reckoned with dissecting-room poisons, he had forgotten to reckon with other sources of infection. In October of that year, a woman was admitted who had malignant disease; of twelve women examined after her, eleven got puerperal fever, and died. In November, a woman was admitted who had a suppurating knee-joint, with sinuses; and eight women were infected from her, and died. Therefore Semmelweis said, "Not only can the particles from dead bodies generate puerperal fever, but any decomposed material from the living body can also generate it, and so can air contaminated by such materials." Henceforth he isolated all infected cases, he enforced the strict use of disinfectants: and the mortality in Clinique A, which in May 1847 had stood at 12.24 per cent., fell in December to 3.04, and in 1848 was 1.27. His work was taken up with enthusiasm by Hebra, Skoda, and Haller; the news of it was sent to every capital in Europe. In February 1849 Haller read a paper on it before the Medical Society of Vienna, and said, "The importance of these observations is above all calculation, _both for the maternity department and for the hospitals in general, but particularly for the surgical wards_." A committee was nominated to report on the whole matter; but it was opposed by the professor in charge of Clinique A, and nothing came of it. In May 1850, Semmelweis opened a great debate on puerperal fever, which occupied three sittings of the Vienna Medical Society. His opponents were there in full force, all the Scribes and Pharisees of the profession. They brought about a vague distrust of his figures and his facts; they got people to believe that there must be "something else" in puerperal fever, as well as the local infection. Semmelweis began to be discouraged. The University authorities made a dead set against him--they refused to renew his appointment, they got him out of the hospital, and out of Vienna. He went to Pesth, and was Professor of Midwifery there; but the same opposition and hostility were at Pesth as at Vienna. Slowly he began to lose his hold over himself, went down hill, became excitable and odd. The end came in July 1865. At a meeting of University professors, he suddenly took a paper from his pocket and read aloud to them a solemn oath, to be enforced on every midwife and every doctor. His mind had given way: he was moved to an asylum at Vienna, and died there a few weeks later. He was only forty-two when he died--_What a wounded name, Things standing thus unknown, shall live behind me._ The contrast between the work of Semmelweis and the work of Pasteur cuts like a knife here. The failure of Semmelweis' teaching may be estimated by the fact that it had all to be done over again. The year of his success at Vienna was 1848. Eight years later, in the Paris Maternity Hospital, between 1st April and 10th May 1856, came such an outbreak of puerperal fever that out of 347 patients 64 died. In 1864, out of 1350 cases, 310 deaths. In Jan.-Feb. 1866, out of 103 cases, 28 deaths: "Women of the lower classes looked upon the Maternité as the vestibule of death." In 1877-78, came the use of carbolic acid and perchloride of mercury at the hospital, thirty years after Semmelweis' work: and, about the same time, Pasteur's discovery of the streptococcus in puerperal fever.[14] Pasteur could demonstrate to his opponents the visible cause of the infection, the thing itself. Roux tells the story:-- "Dans le pus des abcès chauds et dans celui des furoncles on constate un petit organisme arrondi, disposé en amas, qu'on cultive facilement dans le bouillon. On le retrouve dans l'ostéomyélite infectieuse des enfants. Pasteur affirme que l'ostéomyélite et le furoncle sont deux formes d'une même maladie, et que l'ostéomyélite est le furoncle de l'os. En 1878, cette assertion a fait rire bien les chirurgiens. "Dans les infections puerpérales, les caillots renferment un microbe à grains arrondis se disposant en files. Cet aspect en chapelet est surtout manifesté dans les cultures. Pasteur n'hésite pas à déclarer que cet organisme microscopique est la cause la plus fréquente des infections chez les femmes accouchées. Un jour, dans une discussion sur la fièvre puerpérale à l'Académie de Médicine, un de ses collégues le plus écoutés dissertait éloquemment sur les causes des épidémies dans les maternités. Pasteur l'interrompt de sa place: _Ce qui cause l'épidémie, ce n'est rien de tout cela: c'est le médecin et son personnel qui transportent le microbe d'une femme malade à une femme saine._ Et comme l'orateur répondit qu'il craignait fort qu'on ne trouve jamais ce microbe, Pasteur s'élance vers le tableau noir, dessine l'organisme en chapelet de grains, en disant, _Tenez, voici sa figure_." (Roux, _L'OEuvre Médicale de Pasteur_. _Agenda du Chimiste_, 1896, p. 528.) [14] See Pasteur's Life, vol. ii. p. 89. All suppuration, and all forms of "blood-poisoning"--abscesses, boils, carbuncles, erysipelas, puerperal fever, septicæmia, pyæmia--are due to minute organisms, various kinds of _micrococcus_. It has indeed been shown that suppuration may, in exceptional conditions, occur without micro-organisms: but practically every case of suppuration is a case of infection either from without or from within the body. There is no room here for any account of the work spent on these micrococci: on their identification, isolation, culture, and inoculation. It is the same with all the pathogenic bacteria--each kind has its own habits, phases and idiosyncrasies, antagonisms and preferences: nothing is left unstudied--the influences of air, light, heat, and chemistry; all the facts of their growth, division, range of variation, grades of virulence, vitality, and products; the entire life and death of each species, and everything that it is, and does, and can be made to do. The difficulties of bacteriology are written across every page of the text-books: above all, the difficulties of attenuating or intensifying the virulence of bacteria, and of immunising animals, and of procuring from them an immunising serum of exact and constant strength. Every antitoxin is the outcome of an immeasurable expenditure of hard international work, unsurpassed in all science for the fineness of its methods and the closeness of its arguments. The older theories of disease had attributed infection to the intemperature of the weather, the powers of the air, or the work of the devil; later, men recognised that there must be a _materies morbi_, something particulate, transmissible, and perhaps alive, but it was still a "nameless something." Therefore, they over-estimated the constitutional, personal aspect of a case of infective disease, against the plain evidence of case-to-case infection or inoculation: they studied with infinite care and minuteness the weather, the environment, the family history, the previous illnesses of the patient--everything, except the immediate cause of the trouble. But modern pathology, like Pasteur, says, _Tenez, voici sa figure_. The antiseptic method was based on bacteriology, resting as it did on the proof afforded by Pasteur that putrefaction was caused by bacteria, and not by the oxygen of the air, as had been previously believed. If any man would measure one very small part of the lives that are saved by this method, let him contrast the treatment of empyema fifty years ago with its treatment now. If he would measure the saving, not of lives but of limbs, let him take the treatment of compound fractures. If he would measure the saving of patients from pain, fever, and long confinement to bed, let him take the ordinary run of surgical cases, not only the major operations but all abscesses, lacerated wounds, foul sores, and so forth. A serum has also been used of late years for the treatment of micrococcus-infection, and has given good results in many cases. It has been used, also, to avert the risk of such infection in certain operations where the antiseptic method cannot be strictly carried out. For the use of a "polyvalent" serum, reference may be made to the recent paper by Dr. W. S. Fenwick and Dr. Parkinson. (_Trans. Roy. Med. Chir. Soc._, 1906.) II ANTHRAX In animals, anthrax is also called _charbon_, splenic fever, or splenic apoplexy: in man, the name of _malignant pustule_ is given to the sore at the point of accidental inoculation, and the name of _woolsorter's disease_ is given to those cases of anthrax where the lungs are infected by inhalation of the spores of the _bacillus anthracis_. The disease occurs among hide-dressers, woolsorters, brushmakers, and rag-pickers: among animals, it occurs in sheep, cattle, horses, and swine:-- "Many of the outbreaks of anthrax in England have been in the neighbourhood of Bradford, and have been traced to the use of infected wool-refuse as manure. A map published by the Board of Agriculture shows that the outbreaks of anthrax are most frequent in those counties of Great Britain where dry foreign wools, hairs, hides, and skins are manufactured into goods. In 1892, there were forty-two outbreaks of anthrax in the West Riding of Yorkshire, as against two in the North Riding, and one in the East Riding. An undoubted fact in connection with anthrax is its tendency to recur on certain farms. During 1895, the disease reappeared on twenty-three farms or other premises in England, and six in Scotland, where it had been reported in the previous year." (Dr. Poore's Milroy Lectures, _On the Earth in relation to Contagia_, 1899.) An admirable account of the disease, as it occurs in man, is given by Dr. Hamer and Dr. Bell, in the valuable series of monographs edited by Dr. Oliver of Newcastle, under the title _Dangerous Trades_ (London, John Murray, 1902). Happily, the disease is very rare among men, even among those most exposed to it. For its treatment in man, an antitoxin has been used with some success: but the cases are too few to be of much importance.[15] [15] Dr. Legge, in his Milroy Lectures, 1905, on Industrial Anthrax (_Lancet_, March and April 1905), gives a full account of Sobernheim's work up to March 1904, and a table of seventy-six cases, treated with Sclavo's serum. The _bacillus anthracis_ was first seen more than fifty years ago: "Anthrax has the distinction of being the first infectious disease the bacterial nature of which was definitely proven."[16] Pollender in 1844, Roger and Davaine in 1850, noted the _petits bâtonnets_ in the blood of sheep dead of the disease, and thought they were some sort of microscopic blood-crystals: it was not till 1863, after Pasteur's study of lactic-acid fermentation, that Davaine realised they were living organisms. Afterward, Koch succeeded in making cultures of them, and reproduced the disease by inoculating animals with these cultures; yet it was said, so late as 1876, that the _bacillus anthracis_ was not the cause of anthrax, but only the sign of it: "Along with the bacilli, there are blood-cells and blood-plasma, and these contain the true amorphous virus of anthrax." Then came Pasteur's work, and reached its end in the experiments at Chartres, and the famous test-inoculations (1881) at Pouilly-le-Fort. [16] See Dr. Flexner's account of the disease, in volume xix. of Stedman's _Twentieth Century Practice_. In the _Agenda du Chimiste_ (1896) M. Roux gives the following account of this work, which he watched from first to last:-- "Vaccination against _charbon_ has now been put to the test of practice for fourteen years. Wherever it is adopted, there the losses from _charbon_ have become insignificant. It was followed by vaccination against swine-measles, _rouget des porcs_, the special study of our poor friend Thuillier. But the immediate result of Pasteur's vaccinations is their least merit: they have given men absolute faith in a science that could show such good works, they have started a movement that is irresistible; above all, they have set going the whole study of immunity, which is bringing us at last to a right way of treating infective diseases. "Virulence is a quality that microbes can lose, or can acquire. Suppose we came across the anthrax-bacillus so far attenuated, in the way of Nature, that it had lost all power to kill--of course we should fail to recognise it; we should take it for an ordinary bacillus of putrefaction: you must watch it through each phase of its attenuation, to know that the harmless organism is the descendant of the fatal virus. But you can give back to it the virulence that it has lost, if you put it, to begin with, under the skin of a very delicate subject, a mouse only one day old. With the blood of this mouse inoculate another, a little older, and it will die. Passing by this method from younger to older mice, we come to kill adult mice, guinea-pigs, then rabbits, then sheep, etc. Thus, by transmission, the virus gains strength as it goes. Doubtless this increase of virulence, that we bring about by experiment, occurs also in Nature; and it is easy to see how a microbe, usually harmless to this or that species of animals, might become deadly to it. Is not this the way that infective diseases have appeared on the earth from age to age? "_See how far we have come, from the old metaphysical ideas about virulence, to these microbes that we can turn this way or that way--stuff so plastic that a man can work on it, and fashion it as he likes._" Pasteur's note on the attenuation of anthrax was presented to the Académie des Sciences on 28th February 1881; and the test-inoculations at Pouilly-le-Fort were made in May of that year. It was hardly to be expected that every country, in every year, should obtain such results as France now takes as a matter of course; and at one time, about twenty-one years ago, there was in Hungary a "conscientious objection" to the inoculation of herds against the disease. But in Italy, from 1st May 1897 to 30th April 1898, the issue of anti-charbon vaccine from one institute alone, the Sero-Therapeutic Institute at Milan, was 165,000 tubes, enough to inoculate 33,734 cattle and 98,792 sheep. And in France, between 1882 and 1893, more than three million sheep, and nearly half a million cattle, were inoculated. The work done in France was published by M. Chamberland, in the _Annales de L'Institut Pasteur_, March 1894. The following translation of his memoir--_Résultats pratiques des Vaccinations contre le Charbon et le Rouget en France_--shows something of the national influence of the Pasteur Institute:-- 1. _Charbon_ "After the famous experiments at Pouilly-le-Fort, MM. Pasteur and Roux entrusted to me the whole method and practice of the vaccinations against _charbon_. Twelve years have passed, and it is now time to put together the results, and to make a final estimate of the value of these preventive inoculations. "Every year we ask the veterinary surgeons to report-- 1. The number of animals they have vaccinated. 2. The number that have died after the first vaccination. 3. The number that have died after the second vaccination, within the twelve days following it. 4. The number that have died during the rest of the year. 5. The average annual mortality before the practice of vaccination. "The sum total of all the reports is given in the following tables:-- VACCINATION AGAINST CHARBON (FRANCE). _Sheep._ +------+-----------+--------+----------+------------------------+ | | | | | Mortality. | | | | | Animals +-------+-------+--------+ | | Total | |Vaccinated|After |After |During | | | Number of | Number |according |First |Second |the rest| | | Animals | of |to Reports|Vacci- |Vacci- |of the | |Years.|Vaccinated.|Reports.|received. |nation.|nation.| Year. | +------+-----------+--------+----------+-------+-------+--------+ | 1882 | 270,040 | 112 | 243,199 | 756 | 847 | 1,037 | | 1883 | 268,505 | 103 | 193,119 | 436 | 272 | 784 | | 1884 | 316,553 | 109 | 231,693 | 770 | 444 | 1,033 | | 1885 | 342,040 | 144 | 280,107 | 884 | 735 | 990 | | 1886 | 313,288 | 88 | 202,064 | 652 | 303 | 514 | | 1887 | 293,572 | 107 | 187,811 | 718 | 737 | 968 | | 1888 | 269,574 | 50 | 101,834 | 149 | 181 | 300 | | 1889 | 239,974 | 43 | 88,483 | 238 | 285 | 501 | | 1890 | 223,611 | 69 | 69,865 | 331 | 261 | 244 | | 1891 | 218,629 | 65 | 53,640 | 181 | 102 | 77 | | 1892 | 259,696 | 70 | 63,125 | 319 | 183 | 126 | | 1893 | 281,333 | 30 | 73,939 | 234 | 56 | 224 | +------+-----------+--------+----------+-------+-------+--------+ | Total|3,296,815 | 990 |1,788,879 | 5,668 |4,406 | 6,798 | +------+-----------+--------+----------+-------+-------+--------+ +------+-------+-----+-------+ | | | | | | | | |Average| | | |Total| loss | | | Total.| loss|before | | | | per |Vacci- | |Years.| | 100.|nation.| +------+-------+-----+-------+ | 1882 | 2,640 | 1.08| 10% | | 1883 | 1,492 | 0.77| " | | 1884 | 2,247 | 0.97| " | | 1885 | 2,609 | 0.93| " | | 1886 | 1,469 | 0.72| " | | 1887 | 2,423 | 1.29| " | | 1888 | 630 | 0.62| " | | 1889 | 1,024 | 1.16| " | | 1890 | 836 | 1.20| " | | 1891 | 360 | 0.67| " | | 1892 | 628 | 0.99| " | | 1893 | 514 | 0.69| " | +------+-------+-----+-------+ | Total|16,872 | 0.94| 10% | +------+-------+-----+-------+ VACCINATION AGAINST CHARBON (FRANCE). _Cattle._ +------+-----------+--------+----------+------------------------+ | | | | | Mortality. | | | | | Animals +-------+-------+--------+ | | Total | |Vaccinated| After | After |During | | | Number of | Number |according | First | Second|the rest| | | Animals | of |to Reports|Vacci- |Vacci- |of the | |Years.|Vaccinated.|Reports.|received. |nation.|nation.| Year. | +------+-----------+--------+----------+-------+-------+--------+ | 1882 | 35,654 | 127 | 22,916 | 22 | 12 | 48 | | 1883 | 26,453 | 130 | 20,501 | 17 | 1 | 46 | | 1884 | 33,900 | 139 | 22,616 | 20 | 13 | 52 | | 1885 | 34,000 | 192 | 21,073 | 32 | 8 | 67 | | 1886 | 39,154 | 135 | 22,113 | 18 | 7 | 39 | | 1887 | 48,484 | 148 | 28,083 | 23 | 18 | 68 | | 1888 | 34,464 | 61 | 10,920 | 8 | 4 | 35 | | 1889 | 32,251 | 68 | 11,610 | 14 | 7 | 31 | | 1890 | 33,965 | 71 | 11,057 | 5 | 4 | 14 | | 1891 | 40,736 | 68 | 10,476 | 6 | 4 | 4 | | 1892 | 41,609 | 71 | 9,757 | 8 | 3 | 15 | | 1893 | 38,154 | 45 | 9,840 | 4 | 1 | 13 | +------+-----------+--------+----------+-------+-------+--------+ |Total | 438,824 | 1,255 | 200,962 | 177 | 82 | 432 | +------+-----------+--------+----------+-------+-------+--------+ +------+-------+-----+-------+ | | | | | | | | |Average| | | |Total| loss | | | Total.| loss|before | | | | per |Vacci- | |Years.| | 100.|nation.| +------+-------+-----+-------+ | 1882 | 82 | 0.35| 5% | | 1883 | 64 | 0.31| " | | 1884 | 85 | 0.37| " | | 1885 | 107 | 0.50| " | | 1886 | 64 | 0.29| " | | 1887 | 109 | 0.39| " | | 1888 | 47 | 0.43| " | | 1889 | 52 | 0.45| " | | 1890 | 23 | 0.21| " | | 1891 | 14 | 0.13| " | | 1892 | 26 | 0.26| " | | 1893 | 18 | 0.18| " | +------+-------+-----+-------+ |Total | 691 | 0.34| 5% | +------+-------+-----+-------+ "Comparing the figures in the fourth column with those in the second, we see that a certain number of veterinary surgeons neglect to send their reports at the end of the year. The number of reports that come to us even tends to get less each year. The fact is, that many veterinary surgeons who do vaccinations every year content themselves with writing, 'The results are always very good; it is useless to send you reports that are always the same.' "We have every reason to believe, as a matter of fact, that those who send no reports are satisfied; for if anything goes wrong with the herds, they do not fail to let us know it at once by special letters. "Anyhow, thanks chiefly to new veterinary surgeons who do send reports, we see that in the twelve years, up to 1st January of this year, we have had exact returns as to 1,788,879 sheep and 200,962 cattle--about half of all those that were vaccinated. "The mortality among sheep and cattle is slightly higher after the first vaccination than after the second. This fact seems to us easy to explain. The animals reported dead include both those that died as the result of the vaccinations, and those that, being already infected at the time, died of the actual disease. But, at the time of second vaccination, the animals are already more or less protected: hence a lower mortality from the actual disease, and a lower sum total. "The whole loss of sheep is about 1 per cent.: the average for the twelve years is 0.94. So we may say that _the whole average loss of vaccinated sheep, whether from vaccination or from the disease itself is about 1 per cent_. The loss of vaccinated cattle is still less: for the period of twelve years, it is 0.34, or about 1/3 per cent. "These results are extremely satisfactory. It is to be noted especially that the average annual death-rate from _charbon_, before vaccination--the average given in these reports--is estimated at 10 per cent. among sheep, and 5 per cent. among cattle. But even if we put it at 6 per cent. for sheep, and 3-1/3 per cent. for cattle, and say that the worth of a sheep is 30 francs, and of an ox or a cow 150 francs--which is well below their real value--even then it is obvious that the advantage of these vaccinations to French agriculture is about five million francs in sheep, and two million in cattle. And these figures are rather too low than too high. 2. _Rouget_ "Some years after the discovery of vaccination against _charbon_, M. Pasteur discovered the vaccine for a disease of swine known under the name of _rouget_. From 1886, these vaccines were prepared and sent out under the same conditions as the vaccines against _charbon_. The following table gives the reports that have come to us of this disease:[17]-- VACCINATION AGAINST ROUGET (FRANCE). +------+-----------+--------+----------+------------------------+ | | | | | Mortality. | | | | | Animals +-------+-------+--------+ | | Total | |Vaccinated|After |After |During | | | Number of | Number |according |First |Second |the rest| | | Animals | of |to Reports|Vacci- |Vacci- |of the | |Years.|Vaccinated.|Reports.|received. |nation,|nation.| Year. | +------+-----------+--------+----------+-------+-------+--------+ | |{ For these| | | | | | | |{ two years| | | | | | | 1886 |{ France | 49 | 7,087 | 91 | 24 | 56 | | |{ and other| | | | | | | |{ countries| | | | | | | 1887 |{ are put | 49 | 7,467 | 57 | 10 | 23 | | |{ together.| | | | | | | 1888 | 15,958 | 31 | 6,968 | 31 | 25 | 38 | | 1889 | 19,338 | 41 | 11,257 | 92 | 12 | 40 | | 1890 | 17,658 | 41 | 14,992 | 118 | 64 | 73 | | 1891 | 20,583 | 47 | 17,556 | 102 | 34 | 70 | | 1892 | 37,900 | 38 | 10,128 | 43 | 19 | 46 | +------+-----------+--------+----------+-------+-------+--------+ |Total | 111,437 | 296 | 75,455 | 534 | 188 | 345 | +------+-----------+--------+----------+-------+-------+--------+ +------+-------+-----+-------+ | | | | | | | | |Average| | | |Total| loss | | | Total.| loss|before | | | | per |Vacci- | |Years.| | 100.|nation.| +------+-------+-----+-------+ | | | | | | | | | | | 1886 | 171 | 2.41| 20% | | | | | | | | | | | | 1887 | 90 | 1.21| " | | | | | | | 1888 | 94 | 1.35| " | | 1889 | 144 | 1.28| " | | 1890 | 254 | 1.70| " | | 1891 | 206 | 1.17| " | | 1892 | 108 | 1.07| " | +------+-------+-----+-------+ |Total | 1,067 | 1.45| 20% | +------+-------+-----+-------+ [17] "The reports for 1893 are at present too few to be utilised for this table." "_The total average of losses during the past seven years is 1.45 per cent., or about 1-1/2 per cent._ "This average is appreciably higher than the average for _charbon_. But it must be noted that the mortality from _rouget_ among swine, before vaccination, was much higher than that from _charbon_ among sheep. It was about 20 per cent.; a certain number of reports speak of losses of 60 and even 80 per cent.: so that almost all the veterinary surgeons are loud in their praises of the new vaccination." The rest of M. Chamberland's paper is concerned with the defects, such as they are, of the vaccinations, and the need of absolute cleanliness in the making of them: which is somewhat difficult for this vast number of vaccinations of animals all over France, and in other parts of the world. The whole story of the discovery is told in M. Valléry-Radot's Life of Pasteur: and the whole story of _rouget_, in the same most fascinating book, vol. ii., p. 180. III TUBERCLE Before Laennec, tubercle had been taken for a degenerative change of the tissues, much like other forms of degeneration. It was Laennec who brought men to see that it is a disease of itself, different from anything else; and this great discovery of the specific nature of tubercle, and his invention of the stethoscope, place him almost level with Harvey. He founded the facts of tubercle, and on that foundation Villemin built. In 1865, Villemin communicated to the Académie des Sciences his discovery that tubercle is an infective disease; that he had produced it in rabbits, by inoculating them with tuberculous matter. _En voici les preuves_, he said. He appealed to these inoculations to prove his teaching:-- _La tuberculose est une affection spécifique. Sa cause réside dans un agent inoculable. L'inoculation se fait très-bien de l'homme au lapin. La tuberculose appartient donc à la classe des maladies virulentes._ It was no new thing to say, or to guess, that phthisis was or might be infective. So far back as 1500, Frascatorius had said that phthisis came "by the gliding of the corrupt and noisome humours of the patient into the lungs of a healthy man." Surely, if clinical experience could suffice, men would have made something out of this wisdom of Frascatorius. They made nothing of it; they waited three hundred years for Villemin to inoculate the rabbits, and then the thing was done--_En voici les preuves_. Three years later, Chauveau produced the disease in animals, not by inoculation, but by the admixture of tuberculous matter with their food. Then, as the work grew, there came a short period of uncertainty: different species of animals are so widely different in their susceptibility to the disease that the results of further inoculations seemed to go against Villemin; and it was not till 1880 that Cohnheim finally established Villemin's teaching, and even went beyond it, making inoculation the very proof of tubercle:-- "Everything is tuberculous, that can produce tuberculous disease by inoculation in animals that are susceptible to that disease: and nothing is tuberculous, that cannot do this." Then, in 1881, came the welcome news that Koch had discovered the bacillus of tubercle. In his first published account of it (24th March 1882) he says:-- "Henceforth, in our warfare against this fearful scourge of our race, we have to reckon not with a nameless something, but with a definite parasite, whose conditions of life are for the most part already known, and can be further studied.... Before all things, we must shut off the sources of the infection, so far as it is in the power of man to do this."[18] [18] "In Zukunft wird man es im Kampf gegen diese schreckliche Plage des Menschengeschlechtes nicht mehr mit einem unbestimmten Etwas, sondern mit einem fassbaren Parasiten zu thun haben, dessen Lebensbedingungen zum grössten Theil bekannt sind und noch weiter erforscht werden. Es müssen vor allen Dingen die Quellen, aus denen der Infektionsstoff fliesst, so weit es in menschlicher Macht liegt, verschlossen werden." In November 1890 he announced, in the _Deutsche Medizinische Wochenschrift_, the discovery of tuberculin. Its failure was one of the world's tragedies. The defeat may not be final, and we may live to see phthisis fought and beaten with its own weapons: but, for the present, it is more to the purpose to consider what other benefits have been gained, from the discovery of the tubercle-bacillus in 1881, in every civilised country in the world. 1. It has given to everybody a more reasonable and hopeful view of phthisis and the diseases allied to it. The older doctrine of heredity, that the child inherits the disease itself, has given way to the doctrine that the inheritance, in the vast majority of cases, is not that of the disease itself, but that of a tendency or increased susceptibility to the disease. 2. It has brought about an immense improvement in the early and accurate diagnosis of all cases. The bacillus found in the sputa, or in the discharges, or in a particle of tissue, is evidence that the case is tuberculous. 3. It has given evidence, which till 1901 was hardly called in question,[19] that _tabes mesenterica_, a tuberculous disease which kills thousands of children every year, is due in many cases to infection from the milk of tuberculous cows. In England alone, in 1895, the number of children who died of this disease was 7389, of whom 3855 were under one year old. [19] At the British Congress on Tuberculosis, London, 1901, Koch stated that bovine tuberculosis and human tuberculosis are not one and the same disease, and that the risk of milk-infection is so small that burdensome restrictions ought not to be enforced. In the general judgment of men well qualified to study the subject, he failed to prove his point. 4. It has proved, and has taught everybody to see the proof, that the sputa of phthisical patients are the chief cause of the dissemination of the disease. By insisting on this fact, it has profoundly influenced the nursing and the home-care of phthisical patients; and it has begun to influence public opinion in favour of some sort of notification of the disease, and in favour of enforcing a law against spitting in public places and conveyances. In some of the principal cities of the United States, laws on this subject have already been enacted. 5. It has greatly helped to bring about the present rigorous control of the meat and milk trades. The following paragraph, taken almost at random, will suffice here:-- "Bacteriological examinations during the past year have shown that more milks are tuberculosis-infected than is generally supposed, and the importance of carefully supervising milk supplies is becoming more and more acknowledged. Veterinary surgeons are practically agreed that tuberculin is a reliable and safe test for diagnosing the presence of tuberculosis in animals, but affords no index of the extent or degree of the disease. The test, however, will not produce tuberculosis in healthy animals, and has no deleterious effect upon the general health of the animals. The London County Council have decided that all cows in London cowsheds shall be inspected by a veterinary surgeon regularly once in every three months, and that a systematic bacteriological examination shall be conducted of milks collected from purveyors." (_Medical Annual_, 1901.) 6. Tuberculin has come into general use for the detection of tuberculosis in cattle, to "shut off the sources of the infection." A full account of this method in different countries was given by Professor Bang, of Copenhagen, at the Fourth Congress on Tuberculosis, Paris, 1898. The injection of tuberculin is followed in eight to twelve hours by a well-marked rise of temperature, if the animal be tuberculous. Of this test, Professor McFadyean, Principal of the Royal Veterinary College, London, says:-- "I have no hesitation in saying that, taking full account of its imperfection, tuberculin is the most valuable means of diagnosis in tuberculosis that we possess.... I have most implicit faith in it, when it is used on animals standing in their own premises and undisturbed. It is not reliable when used on animals in a market or slaughter-house. A considerable number of errors at first were found when I examined animals in slaughter-houses after they had been conveyed there by rail, etc. Since that, using it on animals in their own premises, I have found that it is practically infallible. I have notes of one particular case, where twenty-five animals in one dairy were tested, and afterwards all were killed. There was only one animal which did not react, and it was the only animal not found to be tuberculous when killed." Two instances of the validity of this test will suffice. In 1899, it was applied to 270 cows on some farms in Lancashire. Of these cows, 180 reacted to the test, 85 did not react, and 5 were doubtful. Tuberculous disease was actually found, when they were killed, in 175 out of the 180 = 97.2 per cent. (_Lancet_, 5th August 1899.) In 1901, Arloing and Courmont published a critical account of the whole subject, and gave the following facts. In 80 calves, which on examination after death were found not tuberculous, the test was negative: in 70 older cattle, which were tuberculous, the test was positive in every case but one, though the dilution of the serum was 1 in 10.[20] It would be easy to add instances of the value of this test, for it is practised far and wide over the world. [20] For references to this paper, and to evidence put forward against the validity of the test, and for criticism of such evidence, see Gould's _Year-Book of Medicine and Surgery_, 1902 (Philadelphia, W. B. Saunders & Company). 7. More recently, the discovery of the "opsonic index," and its use by Sir Almroth Wright and others, has given a great advance to the observation and treatment of cases of tuberculosis. The administration of the "new tuberculin" is now timed and measured with an accuracy which was absolutely impossible a few years ago. It is a far cry, from the present method of counting how many tubercle-bacilli are taken up by a single blood-cell, back to Villemin's rabbits. Every inch of the way, from 1881 onward, the pathological study of every form of tuberculosis, medical or surgical, human or bovine, has been dependent on bacteriology; that is to say, on experiments on animals. IV DIPHTHERIA The bacillus of diphtheria, the Klebs-Loeffler bacillus, was first described by Klebs in 1875, and was first obtained in pure culture by Loeffler in 1884. Its isolation was a matter of great difficulty, and the work of many years, because of its association in the mouth with other species of bacteria. The following table, from Hewlett's _Manual of Bacteriology_, is a good instance of one of many practical difficulties. Out of 353 cases of diphtheria, bacteriological examination found the diphtheria-bacillus alone in 216 cases. In the remaining 137 it was associated with the following organisms:-- Streptococci 6 Staphylococci 55 Bacilli 19 Torulæ 9 Sarcinæ 6 Streptococci and micrococci 2 Micrococci and bacilli 9 Streptococci and bacilli 1 Torulæ and bacilli 1 Micrococci and sarcinæ 6 Micrococci and torulæ 4 Many forms present together 19 ---- 137 ---- In December 1890 came the news that Behring and Kitasato had at last cleared the way for the use of an antitoxin:-- "Our researches on diphtheria and on tetanus have led us to the question of immunity and cure of these two diseases; and we succeeded in curing infected animals, and in immunising healthy animals, so that they have become incapable of contracting diphtheria or tetanus." Aronsen, Sidney Martin, Escherich, Klemensiewicz, and many more, were working on the same lines; and in 1893, Behring and Kossel and Heubner published the first cases treated with antitoxin. Then, in 1894, came the Congress of Hygiene and Demography at Budapest, and Roux's triumphant account of the good results already obtained. Thus the treatment is not many years old; but, if the whole world could tabulate its results, the total number of lives saved would already be somewhere above a quarter of a million. Men found it hard at first to believe the full wonder of the discovery: the medical journals of 1895 and 1896 still contain the fossils of criticism--all the _may be_ and _must be_ of the earlier debates on the new treatment. The finest of all these fossils is embedded in the _Saturday Review_ of 2nd Feb. 1895--_It is a pity that the English Press should continue to be made the cat's-paw of a gang of foreign medical adventurers._ To get at the truth, we must reckon in thousands: take, out of a whole mass of evidence, all just alike, the reports from London, Berlin, Munich, Vienna, Strasbourg, Cairo, Boston, and New York; these to begin with. Or the following facts, cut almost at random out of the medical journals:-- "The medical report of the French army states that since the introduction of the serum-treatment of diphtheria, the mortality among cases of that disease had fallen from 11 per cent. to 6 per cent." (_Brit. Med. Journ._, 3rd September 1898.) "Professor Krönlein (Zürich) exhibited statistical tables, showing that the prevalence of diphtheria in the canton of Zürich had been nearly uniform during the past fifteen years; and that the mortality rapidly decreased as soon as antitoxic serum was used on a somewhat larger scale. In his clinic, all the patients were examined bacteriologically, and serum was administered in every case of diphtheria without exception. Of 1336 cases treated before the serum-period, 554 = 39.4 per cent. died; whilst during the serum-period there were 55 deaths among 437 cases = 12 per cent. In cases of tracheotomy, the death-rates before and during the serum-period were 66 and 38.8 per cent. respectively." (_Lancet_, 7th May 1898, Report of German Surgical Congress at Berlin.) "Dr. Kármán was entrusted by the Hungarian Government with the task of instituting measures for preventing the spread of diphtheria in a village and its neighbourhood. As general hygienic regulations accomplished nothing, he tried preventive inoculation.... Among 114 children thus treated, there was during the next two months no case of diphtheria, although the disease was prevalent in the village up to the date at which inoculation commenced, and continued to rage in the surrounding villages afterwards. During those two months, only one case of diphtheria appeared in the village, and that was in an uninoculated child; while, in the previous five months, 18.3 per cent. of the village children had been attacked, of whom eight died, six not having been treated with serum. Considering the wretched hygienic condition of the village, the harmlessness of preventive inoculations, and the continuance of the disease in the neighbouring villages, where diphtheria-vaccination was not carried out, the extraordinary value of the inoculations, in the prophylaxis of diphtheria, can hardly be denied." (_Brit. Med. Journ._, 16th January 1897.) "The most striking confirmation of the value of antitoxin has been afforded where the supply ran short during an epidemic. In Baginsky's clinic, the interruption of the serum-treatment promptly raised the mortality from 15.6 to 48.4 per cent." (_Brit. Med. Journ._, 20th October 1895.) "In an analysis of the ratio of mortality in 266 German cities of about 15,000 inhabitants, it was found that the ratio of mortality per 100,000 of the living, before antitoxin was used, varied from 130 to 84 from 1886 to 1893, while the ratio from 1894 to 1897 varied from 101 to 35. It is a significant fact that during 1894, when, although antitoxin was used to a certain extent, it was not in general use, the ratio was 101; that when antitoxin was used more extensively, in 1895, the ratio was 53; that in 1896 it was 43; that in 1897, when antitoxin was very generally used, the rate fell to 35." (_Trans. Massachusetts Med. Soc._, 1898.) "Dr. Gabritchefski points out that in recent years the number of persons (in Russia) attacked by the disease has increased, the figures for the whole of Russia rising from about 100,000 or 120,000, ten years ago, to considerably over 200,000 in 1897. The introduction of the serum treatment has, however, had a marked effect on the mortality of the disease; and the actual number of deaths from diphtheria has either not increased at all, or has slightly diminished." (_Lancet_, 5th Aug. 1899.) Of course there will still be bad diphtheria years and good diphtheria years: for example, the death-rate of the population of England, from diphtheria, was higher during the years 1893-1899 than during the years 1889-1892. Antitoxin can no more prevent a bad diphtheria year than an umbrella can prevent a wet day. But in limited outbreaks of diphtheria, such as occur in a village, an asylum, a school, or a large family of young children, it can be used, and is used, as a prophylactic, and with admirable results. The example of Dr. Kármán, just quoted, is one of the earliest instances of this preventive use of antitoxin: other instances, of equal importance, are given in the _Boston Medical and Surgical Journal_, December 1897 and March 1898; and in the _Lancet_, 2nd April 1898, and 28th January 1899. A summary of later experiences of this preventive use of antitoxin in different countries is given by Dr. Wilcox of New York, and Dr. Stevens of Philadelphia, in Gould's _Year-Book_ for 1902:-- "At a meeting of the Société de Pédiatrie (Paris), held June 1901, a resolution was adopted affirming that preventive inoculations present no serious dangers, and confer immunity in the great majority of cases for some weeks, and recommending their employment in children's institutions and in families in which scientific surveillance cannot be exercised. Netter stated that he had collected 32,484 observations (cases) of prophylactic injections, and after eliminating cases in which the disease developed in less than twenty-four hours after injection, or more than thirty days after, there were 6 per cent. of failures. On the other hand, the author stated that he had recently made ninety preventive injections with but 2.17 per cent. of failures. Potter reports a series of twenty-four families in which preventive injections were used. Only one case of diphtheria occurred. In another series of cases, in which no prophylactic injections were given, the disease occurred secondarily in one-third of the houses, and one-sixth of the inmates contracted the disease, in spite of the fact that a large number of the primary cases were removed to the hospital. Blake reports a series of thirty-five prophylactic injections. The treatment was instituted after three cases of diphtheria had developed in a children's home. No secondary cases developed. Voisin and Guinon describe an epidemic of diphtheria in the Salpetrière Hospital among idiots and epileptics. Prophylactic injections were given to all those exposed to the contagion. After that, but four cases appeared, all mild in character. One severe case developed, however, two weeks later, ending fatally in twenty-four hours, showing that the prophylactic action of the antitoxin, while efficacious, is not of very long duration." It would be easy to prolong _ad infinitum_ the proofs of the curative and preventive efficacy of the antitoxin: it would be impossible to find any evidence to be weighed for one moment against these proofs. There are three early records that ought to be quoted more fully: the 1894 report from the Hospital for Sick Children, Paris; the 1896 report of the American Pædiatric Society; and the 1898 report of the Clinical Society of London. I The report from the Hospital for Sick Children, Paris, is contained in a memoir, _Sérum-Thérapie de la Diphtérie_, the joint work of MM. Roux, Martin, and Chaillon (_Annales de l'Institut Pasteur_, September 1894). It gives the results of the serum-treatment during February to July 1894. The cases were not selected: the antitoxin was given in every case that was proved, by bacteriological examination, to be diphtheria--with the exception of 20 cases where the children were just dying when they were brought to the hospital. No change was made either in the general treatment or in the local applications to the throat; these were the same that had been used in former years: _le sérum est le seul élément nouveau introduit_. In 1890-1893, before the serum-treatment, 3971 children were admitted to the diphtheria wards, and 2029 of them died. The percentage of these deaths was-- In 1890 55.88 } " 1891 52.45 } Average = 51.71. " 1892 47.64 } " 1893 48.47 } The serum was used from 1st February to 24th July 1894. During this period 448 children were admitted, of whom 109 died = 24.5. During the same period (February to June) the Trousseau Hospital, where the serum was not used, had 520 cases, with 316 deaths = 60.0. The cases at the Hospital for Sick Children must be divided into those that required tracheotomy and those that did not require it:-- MORTALITY AMONG CASES NOT REQUIRING TRACHEOTOMY. In 1890 47.30 } " 1891 46.64 } Average = 33.94. " 1892 38.8 } " 1893 32.02 } During the serum-period, the mortality of these cases was 12.0. At the Trousseau Hospital, without the serum, the mortality of these cases during the same period was 32.0. MORTALITY AMONG CASES REQUIRING TRACHEOTOMY. In 1890 76.35 } " 1891 68.36 } Average = 73.49. " 1892 74.6 } " 1893 73.45 } During the serum-period, the mortality of these cases was 49.0. At the Trousseau Hospital, without the serum, the mortality of these cases during the same period was 86.0. Setting aside, out of the 448 children, those cases of "membranous sore throat" or "pseudo-diphtheria," in which the Klebs-Loeffler bacillus was not found, there remain 320 cases where it was found. Of these 320 children, 20 were just dying on admission, and did not receive the serum. Of the 300 who received it, 78 died = 26.0. Before the serum-period, the mortality of these cases at the same hospital was about 50.0. The complications of diphtheria, such as paralysis, were much less frequent during the serum-period than they had been before it. II Report of the American Pædiatric Society's Collective Investigation into the use of Antitoxin in the treatment of diphtheria in private practice. (Eighth Annual Meeting, Montreal, May 1896.) From the _New York Medical Record_, 4th July 1896. This vast collection of cases is of special interest, because they occurred in private practice. In most of them the nature of the disease was proved by bacteriological examination; in the rest, the clinical evidence was decisive: "It is possible that among the latter we have admitted some streptococcus cases, but the number of such is certainly very small." All other doubtful cases, 244 in number, were excluded. Three thousand three hundred and eighty-four cases were reported by 613 physicians from 114 cities and towns, in 15 different States, the District of Columbia, and the Dominion of Canada. To these 3384 cases were added 942 cases from tenement-houses in New York, and 1468 cases from tenement-houses in Chicago. The New York and Chicago cases were, most of them, treated by a corps of inspectors of the Health Board of the city; and the municipal surveillance was very strict at Chicago:-- "There are very few hospitals in America that receive diphtheria patients.... It was the custom in Chicago to send an inspector to every tenement-house case reported, and to administer the serum unless it was refused by the parents. These cases were therefore treated much earlier, and the results were correspondingly better than were obtained in New York, although the serum used was the same in both cities, viz., that of the New York Health Board." The sum total of results was 5794 cases, with 713 deaths = 12.3 per cent., including every case returned; but 218 were moribund at the time of injection, or died within twenty-four hours of the first injection. "Should these be excluded, there would remain 5576 cases in which the serum may be said to have had a chance, with a mortality of 8.8 per cent. Of 996 cases injected on the first day of the disease, 49 died = 4.9% " 1616 " on the second " 120 " = 7.4" " 1508 " on the third " 134 " = 8.8" " 758 " on the fourth " 147 " = 20.7" " 690 " on or after the fifth " 244 " = 35.3" And in 232 cases, where the day of injection was unknown, there were 19 deaths = 8.2 per cent. "No one feature of the cases of diphtheria treated by antitoxin has excited more surprise among the physicians who have reported them than the prompt arrest, by the timely administration of the serum, of membrane which was rapidly spreading downward below the larynx. Such expressions abound in the reports as 'wonderful,' 'marvellous,' 'in all my experience with diphtheria, have never seen anything like it before,' etc. "Turning now to the operative cases, we find the same remarkable effects of the antitoxin noticeable. Operations were done in 565 cases, or in 16.7 per cent. of the entire number reported. Intubation was performed 533 times, with 138 deaths, or a mortality of 25.9 per cent. In the above are included 9 cases in which a secondary tracheotomy was done, with 7 deaths. In 32, tracheotomy only was done, with 12 deaths, a mortality of 37.4 per cent. Of the 565 operative cases, 66 were either moribund at the time of operation or died within twenty-four hours after injection. Should these be deducted, there remain 499 cases operated upon, by intubation or tracheotomy, with 84 deaths, a mortality of 16.9 per cent. "Let us compare the results of intubation, in cases in which the serum was used, with those obtained with this operation before the serum was introduced. Of 5546 intubation cases in the practice of 242 physicians, collected by M'Naughton and Maddren (1892), the mortality was 69.5 per cent. Since that time, statistics have improved materially by the general use (in and about New York, at least) of calomel fumigations. With this addition, the best results published (those of Brown) showed in 279 cases a mortality of 51.6 per cent. "But even these figures do not adequately express the benefit of antitoxin in laryngeal cases. Witness the fact that over one-half the laryngeal cases did not require operation at all. Formerly, 10 per cent. of recoveries was the record for laryngeal cases not operated upon. Surely, if it does nothing else, the serum saves at least double the number of cases of laryngeal diphtheria that has been saved by any other method of treatment." III In 1898, the Clinical Society published the Report of their Special Committee, based on 633 cases (_Trans. Clin. Soc._, xxxi., 1898, pp. 1-50). The whole report should be read carefully; but there is room here for nothing more than the latter part of it. This is given at length. A _Table showing the General Mortality of cases treated, on the same day of the disease, with and without Antitoxin._ +----------------------------++---------------------------++----------+ | ||METROPOLITAN ASYLUMS BOARD || | | ANTITOXIN COMMITTEE: || 1894: ||Difference| | 633 Cases treated ||3042 Cases treated without || of | | with Antitoxin. || Antitoxin. || Per- | +----------------------------++---------------------------++ centage. | |Day of the| C | D | M || Day of | C | D | M || | |Disease on| a | e | o ||Admission| a | e | o || | |which | s | a | r || to | s | a | r || | |Treatment | e | t | t ||Hospital.| e | t | t || | |was begun.| s. | h | i || | s. | h | a || | | | | s. | l || | | s. | l || | | | | | i || | | | i || | | | | | t || | | | t || | | | | | y || | | | y || | | | | | || | | | || | | | | | %. || | | | %. || | +----------+-----+-----+-----++---------+-----+-----+-----++----------+ | 1st | 20 | 2 | 10.0|| 1st | 133| 30 | 22.5|| 12.5 | | 2nd | 92 | 10 | 10.8|| 2nd | 539| 146 | 27.0|| 16.2 | | 3rd | 133 | 20 | 15.0|| 3rd | 652| 192 | 29.4|| 14.4 | | 4th | 130 | 26 | 20.0|| 4th | 566| 179 | 31.6|| 11.6 | | 5th | 258 | 66 | 25.5|| 5th |1,152| 355 | 30.8|| 5.3 | |and after.| | | || | | | || | +----------+-----+-----+-----++---------+-----+-----+-----++----------+ | Totals | 633 | 124 | 19.5|| Totals |3,042| 902 | 29.6|| 10.1 | +----------+-----+-----+-----++---------+-----+-----+-----++----------+ B _Summary and Conclusions of the Committee's Report_ "The material for the investigation of the clinical value of the antitoxin serum in the treatment of diphtheria was not obtained from selected, but from consecutive, cases, reported from the general hospitals and the fever hospitals of the Metropolitan Asylums Board; all were made use of which fulfilled the requirements of the Committee. "The Committee rejected all cases in which satisfactory proof of the existence of true diphtheria was not shown, either by the presence of the _Bacillus diphtheriæ_ upon bacteriological examination, or by the occurrence of paralysis in the course of the illness. All were also rejected in which the amount of antitoxin administered was stated in cubic centimetres and not in normal units, the Committee having no means by which the strength of the antitoxin could in these cases be determined. "Six hundred and thirty-three cases form the basis on which the report is drawn up; 549 were treated with antitoxin obtained from the laboratory of the Royal Colleges of Physicians and Surgeons; the remainder, 84 in number, were injected with antitoxin obtained from other sources. In nine instances, antitoxin from two different sources was injected into the same patient. "Statistics of the disease before the use of antitoxin are introduced as control series; these were obtained from the fever hospitals of the Metropolitan Asylums Board, and from the general hospitals; and, like the antitoxin series, are compiled from consecutive and not from selected cases. "The general mortality, under the antitoxin treatment, was 19.5 per cent.; a reduction of 10 on the percentage mortality of the cases treated in the hospitals of the Metropolitan Asylums Board in 1894. If 15 fatal cases, in which death took place within twenty-four hours of the first injection, be deducted, the mortality falls to 15.6 per cent.; which is very little more than half the mortality during 1894 under other forms of treatment. "The lessened mortality is especially noticeable in the earlier years of life, the percentage mortality of children under five being 26.3, as opposed to 47.4. In the next period of five years, the percentage of mortality is 16.0, as opposed to 26.0; whilst after ten years of age the difference in the mortality is slight.[21] [21] After childhood, the disease is much less fatal. "Laryngeal diphtheria is admittedly the most dangerous form. The laryngeal cases have a percentage mortality of 23.6 in the antitoxin, as compared with 66.0 in the non-antitoxin series. In the cases in which laryngeal symptoms are so severe as to necessitate tracheotomy, the saving of life by the use of antitoxin is very marked, the mortality being reduced one-half, to 36.0 as opposed to 71.6 per cent. "The strongest evidence of the value of the antitoxin treatment is that, in addition to reducing the general mortality by one-third, the duration of life in the fatal cases is decidedly prolonged. These two facts taken together conclusively prove the beneficial effects of the antitoxin treatment. "The incidence of paralysis is greater in the antitoxin than in the control series. This increased number is partly explained by the lessened mortality, and partly by the longer duration of life in the fatal cases affording time for the development of paralytic symptoms. The percentage mortality of those who had some form or other of paralysis is lower in the antitoxin than in the control series; so that, notwithstanding the apparent greater risk of paralysis supervening, the probability of final recovery is greater. "No definite conclusion can be drawn, for the reasons stated in the body of the report, as to the advantage of administering the whole of the antitoxin within forty-eight hours of the first injection, or continuing it for a longer period; but evidence is afforded of the importance of its administration as early as possible in the course of the disease; the percentage mortality in cases injected on the first and second days of the disease being 10.7, as compared with 25.5 for those first receiving the injection on the fifth or some subsequent day. "No conclusion can be drawn, from the cases reported on, as to the amount of antitoxin which should be used to produce the best effects; but they show that the administration of very large doses is followed by no pronounced ill effects. "The injection of antitoxin is responsible for the production of rashes, joint-pains, and possibly for the occurrence of late pyrexia. In 34.7 per cent. the injections were followed by rashes. Some amount of fever accompanied the rash in 60 per cent. In only 9.4 per cent. of those in whom rashes were observed did death ensue. "Joint-pains were observed in 40, or 6.3 per cent. of the whole number, and all but five of them had a rash as well. "In 26, or 65 per cent. of the joint-pains, some rise of temperature accompanied the pain. A rise of temperature during convalescence, accompanied by either rash or joint-pain, occurred in 27, or 4.2 per cent. of the whole number. "No connection could be traced between the amount of antitoxin administered and the occurrence of rashes or late pyrexia, but the pain in and about the joints appears to have a relationship to the amount of antitoxin used. "The results of the Committee's investigation tend to show that by the use of antitoxin-- 1. The general mortality is reduced by one-third. 2. The mortality in tracheotomy falls by one-half. 3. Extension of membrane to the larynx very rarely occurs after the administration of antitoxin. 4. The duration of life in the fatal cases is decidedly prolonged. 5. The number of fatal cases is less when antitoxin is used early in the illness than in those which do not receive it until a later period. 6. The frequency of the occurrence of paralysis is not diminished, but the percentage of recoveries in cases with paralysis is slightly increased.[22] 7. Rashes are produced in about one-third of the cases, and are attributable to the antitoxin. 8. Pain, and occasionally swelling about the joints, are produced in a number of cases. 9. Even when used in large doses, no serious ill effects have followed the injection of antitoxin." [22] For an exhaustive and wise study of the diphtheritic paralyses, see Dr. Woollacott's essay in the _Lancet_, 26th August 1899: "The use of antitoxic serum in the treatment of diphtheria has, up to the present time, in the London fever hospitals, had two main results--the death-rate has fallen, while the paralysis-rate has risen. In the hospitals of the Metropolitan Asylums Board, the former has been reduced from 29 per cent. to 15.3 per cent., while the latter has risen from 13 per cent. to as high as 21 per cent. in 1896. This increase of paralysis is chiefly due to the fact that many more patients now recover from the primary disease, and live long enough for paralysis to show itself. _During the last two years, however, the occurrence of paralysis has begun to diminish in frequency.... The earlier antitoxin is given in diphtheria, the less likely is paralysis to follow._" It is to be borne in mind that post-diphtheritic paralysis, in the great majority of cases, affects only a very small group of muscles; of Dr. Woollacott's tabulated cases, 377 were of this kind, and 97 were severe. And "the type of paralysis has, on the whole, become less severe, or at all events less dangerous to life." * * * * * The foregoing reports belong to ancient history. Let us leave them, and study the record of the hospitals of the Metropolitan Asylums Board. They serve a city of 121 square miles, and 4-1/2 millions of inhabitants. The use of the antitoxin in the hospitals of the Metropolitan Asylums Board began in 1895. It had been used in 1894 on a few cases only, during the latter part of the year, and had been procured with much difficulty from various sources, chiefly from the Institute of Preventive Medicine. On 9th November 1894, the Board applied to the Laboratories' Committee of the Royal Colleges of Physicians and of Surgeons, asking them to undertake the supply. Arrangements were made for this purpose; and the sum of £1000 was given by the Goldsmiths' Company. Dr. Sims Woodhead, then Director of the Laboratories of the Conjoint Colleges, now Professor of Pathology at Cambridge, was put in charge of the bacteriological work and the preparation of the serum, with a host of expert colleagues: the administration of the treatment was the work of the medical officers of the hospitals of the Metropolitan Asylums Board. The experiences of 1895 are given in the following passages from the joint report to the Board from the medical superintendents:-- "The period covered by the report extends from 1st January 1895 to 31st December of the same year. During this time--with the exception of an interval of three months at the Eastern Hospital, when its use was suspended; of three months at the Fountain, and to a considerable extent throughout the year at the South-Eastern Hospital, when all cases were consecutively treated, irrespective of their severity--the serum was administered _only to cases which at the time of admission were severe, or which threatened to become so_. In a certain number, the patients being moribund at the time of their arrival, and beyond the reach of any treatment, no antitoxin was given. _No change has taken place during the year in the local treatment of the cases, nor has there been any new factor in the treatment other than the injection of antitoxin_. "It must be clearly understood that, with the exceptions previously stated, it has been the practice at each of the hospitals to administer serum to _those cases only in which the symptoms on admission were sufficiently pronounced to give rise to anxiety, the mild cases not receiving any_. "_No less than 46.4 per cent. of the antitoxin cases were under five years of age, against 32.5 per cent. in the non-antitoxin group_; and only 16.1 per cent. in the former class were over ten years of age, against 33.8 per cent. in the latter. The high fatality of diphtheria in the earlier years of life is notorious. "It is obvious, therefore, that to compare the mortality of those treated with antitoxin with that of those which during the same period were not so treated, would be to institute a comparison between the severe cases and those of which a large proportion were mild. This would clearly be misleading. "The only method by which an accurate estimate can be obtained as to the merits of any particular form of treatment, is by comparing a series of cases in which the remedy has been employed with another series not so treated, but which are similar, so far as can be, in other respects. This, in the present instance, is impossible; but, having regard to the fact that 61.8 of the 1895 cases were treated with serum, an approximately accurate conclusion can be drawn by contrasting all cases of diphtheria completed during 1895, the antitoxin period, with all cases completed during 1894. "The year 1894 has been selected for the purpose of comparison, not only because it is the year immediately preceding the antitoxin period, but because the average severity of the cases has been, in our opinion, about equal. Moreover, the death-rate in 1894 was slightly lower than it had been in any previous year. " ... Of 3042 patients of all ages treated during 1894, 902 died--a mortality of 29.6 per cent.; whereas, of 3529 cases treated during 1895, 796 died--a mortality of 22.6 per cent.; the difference in percentage between the two rates being therefore 7.1. This, assuming that the former rate would otherwise have been maintained, represents a saving of 250 lives during the past year. INFLUENCE OF AGE. _Table showing variations in reduction of mortality obtained with Antitoxin at different ages._ +--------+------------------------+------------------------+ | | Antitoxin Cases, | All Cases, | | | 1895. | 1895. | | Ages. +------+-------+---------+------+-------+---------+ | |Cases.|Deaths.|Mortality|Cases.|Deaths.|Mortality| | | | |per cent.| | |per cent.| +--------+------+-------+---------+------+-------+---------+ |Under 5 | 1013 | 379 | 37.4 | 1453 | 497 | 34.2 | | " 10 | 1829 | 575 | 31.4 | 2720 | 744 | 27.3 | | " 15 | 2056 | 606 | 29.4 | 3144 | 779 | 24.7 | |All ages| 2182 | 615 | 28.1 | 3529 | 796 | 22.5 | +--------+------+-------+---------+------+-------+---------+ +--------+------------------------+------------+ | | All Cases, | Diff. in | | | 1894. |Mortalities,| | Ages. +------+-------+---------+ 1894 | | |Cases.|Deaths.|Mortality| and | | | | |per cent.| 1895. | +--------+------+-------+---------+------------+ |Under 5 | 1171 | 556 | 47.4 | 13.2 | | " 10 | 2246 | 836 | 37.2 | 9.9 | | " 15 | 2609 | 877 | 33.6 | 8.9 | |All ages| 3042 | 902 | 29.6 | 7.1 | +--------+------+-------+---------+------------+ For every age-group, with the single exception of that comprising the years 15 to 20 (the numbers of which are small), the percentage mortality was less in the 1895 than in the 1894 cases. The reduction in mortality was greatest in early life. INFLUENCE OF TIME OF COMING UNDER TREATMENT. _Table showing percentage mortality in relation to day of disease on which cases came under treatment._ +---------------+--------+--------+-----------+ |Day of Disease.| 1894. | 1895. |Difference.| +---------------+--------+--------+-----------+ | 1st | 22.5 | 11.7 | 10.8 | | 2nd | 27.0 | 12.5 | 14.5 | | 3rd | 29.4 | 22.0 | 7.4 | | 4th | 31.6 | 25.1 | 6.5 | | 5th and over | 30.8 | 27.1 | 3.7 | +---------------+--------+--------+-----------+ | Total | 29.6 | 22.5 | 7.1 | +---------------+--------+--------+-----------+ "It will be seen that the percentage mortality of cases admitted on the same day of disease is less in every instance in the year 1895. The difference is most marked in the case of those patients who were admitted on the first and second day of illness, viz., 10.8 and 14.5 respectively. "Both in 1894 and 1895, no less than over 37 per cent. of the patients were admitted on, or after, the fifth day of disease. And, moreover, while in 1894 as many as 59.2 per cent. of the fatal cases were not brought under treatment until the fourth day, or later, in 1895, the antitoxin year, the proportion was even higher, viz., 67.7 per cent. _Laryngeal Cases_ "The tracheotomy results at each hospital are more favourable in the year 1895 than in 1894, the mortality ranging in the latter year at the different hospitals between 90 per cent. and 59.4 per cent., whereas in 1895 the range was from 56.2 to 40.5. "The combined tracheotomy mortality for all the hospitals, which in 1894 was 70.4 per cent., has fallen to 49.4 per cent. in 1895. This is a lower death-rate than has ever been recorded in any single hospital of the Board for a year's consecutive tracheotomies. In other words, rather more than 50 per cent. of children on whom the operation has been performed have been saved since the employment of antitoxin. In one of the hospitals no less than a fraction under 60 per cent. survived, although the recoveries in that hospital in any previous year did not exceed 25 per cent., and in the preceding year--viz., 1894--were as low as 10 per cent. "The improved results in the tracheotomy cases of 1895 have also been shared by analogous cases in which the operation was not performed. The percentage mortality of all laryngeal cases has fallen from 62 in 1894 to 42.3 in 1895. "Moreover, the number of laryngeal cases which required tracheotomy has fallen in 1895 to 45.3 per cent., whereas in 1894 it was 56 per cent. "The following tables briefly summarise the foregoing results. As no returns for 1894 were furnished by the Fountain Hospital by reason of the smallness of the numbers, the Fountain cases have also been omitted from the 1895 figures, in order that the two series may be rendered strictly comparable:-- 1. _Comparative Mortality of Laryngeal Cases at all Hospitals, except the Fountain._ +-----+------+-------+----------+ |Year.|Cases.|Deaths.|Percentage| | | | |Mortality.| +-----+------+-------+----------+ |1894 | 466 | 289 | 62.0 | |1895 | 468 | 196 | 41.8 | +-----+------+-------+----------+ 2. _Comparative Results in Tracheotomy Cases at all Hospitals, except the Fountain._ +-----+------+-------+----------+ |Year.|Cases.|Deaths.|Percentage| | | | |Mortality.| +-----+------+-------+----------+ |1894 | 261 | 184 | 70.4 | |1895 | 219 | 108 | 49.3 | +-----+------+-------+----------+ 3. _Comparative Number of Laryngeal Cases which required Tracheotomy at all Hospitals, except the Fountain._ +-----+------+--------------+--------------+ |Year.|Cases.|Tracheotomies.|Percentage of | | | | |Tracheotomies.| +-----+------+--------------+--------------+ |1894 | 466 | 261 | 56.0 | |1895 | 468 | 219 | 46.8 | +-----+------+--------------+--------------+ "On these tables further comment seems unnecessary. _Summary_ "The improved results in the diphtheria cases treated during the year 1895, which are indicated by the foregoing statistics and clinical observations, are-- 1. A great reduction in the mortality of cases brought under treatment on the first and second day of illness. 2. The lowering of the combined general mortality to a point below that of any former year. 3. The still more remarkable reduction in the mortality of the laryngeal cases. 4. The uniform improvement in the results of tracheotomy at each separate hospital. 5. The beneficial effect produced on the clinical course of the disease. _Conclusions_ "A consideration of the foregoing statistical tables and clinical observations, covering a period of twelve months, and embracing a large number of cases, in our opinion sufficiently demonstrates the value of antitoxin in the treatment of diphtheria. "It must be clearly understood, however, that to obtain the largest measure of success with antitoxin it is essential that the patient be brought under its influence at a comparatively early date--if possible, not later than the second day of disease. From this time onwards, the chance of a successful issue will diminish in proportion to the length of time which has elapsed before the treatment is commenced. This, though doubtless true of other methods, is of still greater moment in the case of treatment by antitoxin. "Certain secondary effects not unfrequently arise as a direct result of the injection of antitoxin in the form in which it has at present to be administered, and even assuming that the incidence of the normal complications of diphtheria is greater than can be accounted for by the increased number of recoveries, we have no hesitation in expressing the opinion that these drawbacks are insignificant when taken in conjunction with the lessened fatality which has been associated with the use of this remedy. "We are further of the opinion that in antitoxic serum we possess a remedy of distinctly greater value in the treatment of diphtheria than any other with which we are acquainted." * * * * * Now let us take the whole record of all the hospitals together. The disease was first admitted in 1888; this year is therefore to be reckoned as incomplete. +--------------------------+----------++--------------+----------+ |Year. |Percentage||Year. |Percentage| | |Mortality.|| |Mortality.| +--------------------------+----------++--------------+----------+ |1888 | 59.35 ||1897 | 17.69 | |1889 | 40.74 ||1898 | 15.37 | |1890 | 33.55 ||1899 | 13.95 | |1891 | 30.63 ||1900 | 12.27 | |1892 | 29.35 ||1901 | 11.15 | |1893 | 30.42 ||1902 | 11.04 | |1894 | 29.29 ||1903 | 9.69 | |1895, first antitoxin year| 22.85 ||1904 | 10.08 | |1896 | 21.20 ||1905 | 8.3 | +--------------------------+----------++--------------+----------+ These results, of course, are but one instance of what has happened, since 1895, in every country all over the civilised world. _Securus judicat orbis terrarum._ We have Siegert's tables (1900), based on no less than 40,038 cases admitted in nine years to sixty-nine hospitals in Germany, Austria, Switzerland, and Paris. He divides these nine years into a "pre-serum period," an "introduction year," and a "serum period." In the pre-serum period the general mortality was 41.5, and the mortality of cases requiring operation was 60; in the serum period, the general mortality was 16.5, and the mortality of cases requiring operation was 37.5. Any bad results that have been recorded from the use of the antitoxin are so rare, in comparison with the hundreds of thousands of injections made, that they do not come to be considered here. And, even though a few have occurred, we may be sure that some of them were due, not to the antitoxin, but to the natural course of the disease.[23] The lesser drawbacks, the occurrence of joint pains and of rashes, are transient and in no way serious. [23] This, of course, does not apply to two instances, in 1901, of accidental contamination of serum. See, for an account of these, _The British Medical Journal_, November 1901. It has been supposed, and said, that the use of the antitoxin increases the complications of the disease. On this point, the best authority is Professor Woodhead's monumental Report (1901), dealing with the Metropolitan Asylums Board cases for 1895 and 1896. He sums up the matter thus:-- "The free use of antitoxin does not raise the percentage of cases of albuminuria. As regards vomiting, the statistics give little information, as vomiting is usually met with only in the very severe cases. This also holds good of anuria. The number of cases of adenitis appears to be distinctly reduced by the use of antitoxin, as the percentage of cases falls as the injections of antitoxin are pushed. The use of antitoxin has also had a perceptible effect in diminishing the cases of nephritis, and it certainly has not aggravated the kidney complications of diphtheria. There can be no doubt that in cases treated with antitoxin there is a greater percentage of cases in which joint-pains occur than in cases not so treated; these, however, are transitory, and are probably the result of some slight change in the blood set up by the action of the serum itself, and not by the antitoxic substance in the serum. The number of primary abscesses has undoubtedly been reduced by the use of antitoxin. It may also be accepted that antitoxic serum has some effect in temporarily raising the temperature, but only during the periods of joint-pains and serum rashes; all these, however, are of comparatively slight importance as compared with the effect the antitoxin has in diminishing the percentage mortality and alleviating the more severe symptoms. "It is of importance to observe that amongst the cases of paralysis following diphtheria the death-rate (32 per cent.) was actually higher amongst those not injected with antitoxin than amongst those where antitoxin was used (30.5 per cent.), although the former paralyses must be looked upon as being the result of a comparatively mild attack of the disease. From this it is evident that, when once paralysis supervenes in these cases, it is quite as fatal in its effects as in the cases (usually those of a more severe type) where antitoxin has been given. Antitoxin _cannot cure_ the degeneration of the nerve, but it _can neutralise_ the diphtheria toxin, and so put a stop to the advance of the degenerative changes due to its action. In 1896, when, of course, antitoxin was given much more freely, the percentage of deaths in the non-injected cases where paralysis had come on fell to 18.4. "Antitoxin rashes occur at a comparatively late stage of the disease. They cannot be looked upon as in any way dangerous, although the secondary rise of temperature, and the irritation of the skin which usually accompany their presence are very undesirable complications, and may retard somewhat the convalescence of nervous and irritable patients. "Antitoxin appears to diminish the liability of the lungs to inflammatory change in severe attacks of diphtheria." * * * * * Now let us take another point of view. If anybody really doubts whether the antitoxin did really save these lives in the hospitals of the Metropolitan Asylums Board, what answer has he got to the following table? It is published in the Board's Report for 1904, and was drawn up by Dr. MacCombie, Medical Superintendent of the Brook Hospital. It shows the supreme importance of giving the antitoxin _at the very beginning of the disease_. The figures in brackets are the total numbers of the cases in the eight years:-- _Percentage Mortality according to Time of coming under Treatment._ +---------------+-----+-----+-----+-----+-----+-----+-----+-----+ |Day of Disease.|1897.|1898.|1899.|1900.|1901.|1902.|1903.|1904.| +---------------+-----+-----+-----+-----+-----+-----+-----+-----+ |(204) 1st | 0.0| 0.0| 0.0| 0.0| 0.0| 0.0| 0.0| 0.0 | |(1278) 2nd | 5.4| 5.0| 3.8| 3.6| 4.1| 4.6| 4.2| 5.43| |(1374) 3rd | 11.5| 14.3| 12.2| 6.7| 11.9| 10.5| 17.6|10.63| |(1086) 4th | 19.0| 18.1| 20.0| 14.9| 12.4| 19.8| 16.7|19.51| |(1382) 5th | | | | | | | | | | and after | 21.0| 22.5| 20.4| 21.2| 16.6| 19.4| 17.3|13.11| +---------------+-----+-----+-----+-----+-----+-----+-----+-----+ Here we see that in 1482 patients, who got the antitoxin within forty-eight hours of the onset of the disease, the mortality was 2-1/4 per cent. In 1278 patients, who did not get the antitoxin till the third day, the mortality was 11-3/4 per cent. That is the result of one day's delay over sending the child into hospital. Again, it is not only lives that are saved, but suffering that is avoided. Just lately, at a meeting of the Chelsea Clinical Society (May 1906), reference was made to this point by Dr. Foord Caiger, Medical Superintendent of the South-Western Hospital. "The number of tracheotomies is less than half what it used to be;" and again, "Instead of the spectacle of a number of patients in great distress, with swollen necks and stuffed-up noses, fretful and crying, such cases are now quite the exception, and, in the few one does come across, the condition lasts for a comparatively short time." And again, "It was quite unusual (before 1895) for a nurse to care to stay very long in charge of one of the diphtheria wards, because she found the work so depressing. But nowadays the diphtheria wards are perhaps the most popular in the hospital, a fact which is mainly owing to the change in the general aspect of the patients and the greatly reduced mortality." (_Clinical Journal_, May 23, 1906.) V TETANUS Before bacteriology, the cause of tetanus (lock-jaw) was unknown, and men were free to imagine that it was due to inflammation travelling up an injured nerve to the central nervous system. This false and mischievous theory was abolished by the experimental work of Sternberg (1880), Carle and Rattone (1884), and Nicolaier (1884), who proved, once and for all, that the disease is an infection by a specific flagellate organism. Their work was of the utmost difficulty, for many reasons. First, because tetanus, in some tropical countries, is so common that it may fairly be called endemic; and many of these tropical cases, there being no record of any external infection, had been taken as evidence that the disease can occur "of itself." Of this frequency of tetanus in tropical countries, Sir Patrick Manson, in his book on _Tropical Diseases_ (1898), says:-- "Tetanus is an exceedingly common disease in some tropical countries. In Western Africa, for example, a large proportion of wounds, no matter how trifling as wounds they may be, if they are fouled by earth or dirt, result in tetanus. The French in Senegambia have found this to their cost. A gentleman who had travelled much in Congoland told me that certain tribes poison their arrows by simply dipping the tips in a particular kind of mud. A wound from these arrows is nearly sure to cause tetanus. In many countries, so general and so extensive is the distribution of the tetanus-bacillus that trismus neonatorum (tetanus of newly-born infants) is a principal cause of the excessive infant mortality." Next, because the tetanus-bacillus has its natural abode in the superficial layers of the soil: here it is associated with a vast number of other organisms, so that its identification and isolation were a work of immeasurable complexity. What mixed company it keeps, is shown by Houston's estimate of the number of microbes per gramme in twenty-one samples of different soils. This number ranged from 8326 in virgin sand, and 475,282 in virgin peat, to 115,014,492 in the soil from the trench of a sewage-farm. In all rich and well-manured soil the tetanus-bacillus may possibly be present; but it was the work of years to dissociate it from the myriads of organisms outnumbering it. Next, because it cannot be got to grow in cultures exposed to the air: its proper place is below the surface of the soil, away from the air; it is "strictly anaërobic," and the attempts to cultivate it by ordinary methods failed again and again. It had to be cultivated below the surface of certain nutrient media, or in a special atmosphere of nitrogen or hydrogen. These and other difficulties for many years delayed the final proof of the true pathology of tetanus. The success of the work was mainly due to Nicolaier. He started from the well-known fact that tetanus mostly comes of wounds or scratches contaminated with particles of earth--such mischances as the grinding of dirt or gravel into the skin, or the tearing of it by a splinter of wood or a rusty nail; as Dr. Poore says, in his Milroy Lectures (1899), "Every child who falls on the ground and gets an abrasion of the skin, all tillers of the soil who get accidental wounds in the course of duty, and every horse which 'breaks its knees' by falling in the London streets, runs potentially a risk of inoculation with tetanus." Nicolaier therefore studied the various microbes of the soil, and made inoculations of garden-mould under the skin of rabbits. He was able, by these inoculations, to produce tetanus in them; and the discharge from the points of inoculation, put under the skin of other rabbits, produced the disease again. He also identified the bacillus, and cultivated it; but in these cultures it was mixed with other organisms, and he failed to isolate it from them. Carle and Rattone, and Rosenbach, were able to produce tetanus in animals by inoculating them with discharge from the wounds of patients attacked by the disease. Finally, Kitasato, in 1889, found a way of obtaining pure cultures of the bacillus. Beginning with impure cultures such as Nicolaier had made, he kept these at a temperature of 36° C. till the bacillus had spored; then, by repeated exposures of the cultures to a temperature of 80° C. for three-quarters of an hour at a time, he killed-off all organisms except the spores of the tetanus-bacillus; then he kept these in an atmosphere of hydrogen, at a temperature of 20° C., and thus got pure cultures. Brieger, Fränkel, Cohen, Sidney Martin, Kanthack, and others, have studied the chemical products of the disease, have obtained them from cultures and from infected tissues, and have been able with these toxins to produce the disease in animals. As with the other infective diseases, so with tetanus, there have been two main lines of researches; the one, toward a fuller knowledge of the chemical changes in the blood and in the central nervous system; the other, toward a fuller knowledge of the nature and ways of the bacillus, and its method of invasion. Before any study of immunity or immunisation, or of neutralisation of the toxins in man by an antitoxin, came the study of the toxins and of the bacillus. It was proved, by an immense quantity of hard work, that the bacillus does not tend to invade the blood, or to pass beyond the lymphatic glands in the immediate neighbourhood of the site of inoculation; that it stays in and about the wound, and there multiplies, and from this site pours into the blood the chemical products which cause the disease; and that these chemical substances have a selective action on certain nerve-cells in the brain and the spinal cord. This is the bare outline of the facts; and no account can be given here of the intricate problems of bacteriology and animal chemistry that have been answered, or are still waiting an answer. At least, it is evident that the whole pathology of tetanus was found, proved, and interpreted by the help of experiments on animals; and that these alone did away with the old false doctrine that the disease was due to rapid extension of inflammation up a nerve to the brain. In 1894 came the use of an antitoxin in cases of the disease, and, in 1895, 42 cases were reported, with 27 recoveries. It cannot be said that any one of the diverse preparations of tetanus-antitoxin, up to this present time, has triumphed over the disease. Tetanus is of all diseases the hardest to reckon with: the first sign of it is the last stage of it; there is no warning, nothing, it may be, but a healed scratch, till the central nervous system is affected with sudden and rapidly advancing degeneration of certain cells. These and other difficulties have stood in the way of an antitoxin treatment; and there is no less difficulty in estimating the efficacy of that treatment. The recovery, under antitoxin, of a "chronic" case cannot always or altogether be attributed to the treatment; and in a very acute case, antitoxin, like everything else, has but small chance of success. Various reports on the antitoxin treatment, published during 1897-1899, give the following figures:-- 26 cases, with 12 recoveries. 98 " 57 " 36 " 25 " 22 " 11 " 51 " 36 " 10 " 7 " Probably the paper by Dr. Lambert of New York, in the _Medical News_, July 1900, gives fairly the general opinion of the treatment, so far as the subcutaneous administration of antitoxin is concerned:-- "The following cases of tetanus, treated with antitoxin, comprise published and unpublished cases. We have a total of 279 cases, with a mortality of 44.08 per cent.: but of these we must rule out 17 cases--4 deaths from intercurrent diseases, 8 deaths in cases in which the antitoxin was given but a few hours before death, and 5 recoveries in which antitoxin was not given until after the twelfth day (as they probably would have recovered without it). We have left 262 cases, with 151 recoveries, and 111 deaths, a mortality of 42.36 per cent. Dividing the cases into acute and chronic, we have 124 acute cases, with 35 recoveries and 89 deaths, a mortality of 71.77 per cent., and 138 chronic cases, with 116 recoveries and 22 deaths, a mortality of 15.94 per cent. In interpreting critically these statistics, we see that in acute cases the mortality is but slightly reduced, being but 72 per cent. instead of 88 per cent. But, in the less acute cases, there is a decided improvement, from 40 per cent. to 16 per cent. Taking the statistics as a whole, there is a distinct improvement in the mortality of tetanus since the introduction of antitoxin." It would be foreign to the present purpose to pursue this matter further: for the other treatments, used by Baccelli and by Krokiewicz, and the sub-dural use of antitoxin, are also founded on experiments on animals; and the same will be true of any better method that shall be developed out of them. The _preventive_ use of the tetanus-antitoxin, for the immunisation of human beings or of animals, has given excellent results. Horses are very apt to be infected by tetanus; and the antitoxin has been used in veterinary practice, both for prevention and for cure. The curative results are not, at present, very good. But, as regards protection against the disease, there is evidence that horses can be immunised against tetanus by the antitoxin with almost mechanical accuracy. In some parts of the world, the loss of horses by tetanus is so common that their immunity is a very important matter; and that the antitoxin does confer immunity on them is shown by statistics from France and from the United States:-- 1. _France._--"The results of Nocard's method of preventive inoculations in veterinary practice are most striking. Among 63 veterinarians, there have been inoculated 2737 animals with preventive doses of antitoxin, and not a single case of tetanus developed; while during the same period, in the same neighbourhoods, 259 cases of tetanus developed in non-inoculated animals." (_Med. News_, 7th July 1900.) 2. _United States._--"Joseph MacFarland and E. M. Ranck, in addition to a synopsis of the method of manufacture of tetanus-antitoxin, give some facts of interest and importance in regard to its use for prophylaxis and treatment. The studies were made upon several hundred horses used for the production of various immunised serums in one of the large laboratories of the United States. The horses, because of the constant manipulations, frequently became infected with tetanus, and in 1897 and 1898, when scrupulous cleanliness and disinfection were the only precautions employed to prevent the disease, the death-rate varied from 8 to 10 per cent. During 1899 nearly two hundred horses were subjected to systematic immunisation with tetanus-antitoxin; and, in spite of otherwise similar conditions, the death-rate descended to 1 per cent." (_Medical Annual_, 1901.) The preventive use of the antitoxin has, of course, a very limited range outside veterinary surgery. Tetanus, thanks to the use of antiseptic or aseptic methods, not only in hospital surgery but also in amateur and domestic surgery, has become a very rare disease, except in tropical countries. It is no longer a "hospital disease"; and, even in war, it no longer has anything like the frequency that it had, for instance, in the War of the Rebellion. A student may now go all his time at a large hospital without seeing more than a very few cases. But, now and again, attention is called to some wholly unsuspected risk of the disease. For example, certain cases of tetanus occurred in Dundee among workers at the jute-mills there:-- "The last victim was a female worker in the jute-mill, who, six days after a crushed and lacerated wound of the foot, developed tetanus and died within twenty-four hours. Some of the dust, taken from under the machine in which the foot was crushed, was found to contain an unusually large number of tetanus-bacilli. The source of the jute used is India." (_Medical News_, August 1900.) Again, at the Gebaer Anstalt at Prague, in 1899, an outbreak of tetanus occurred, with several deaths; but it was stopped when a preventive dose of the antitoxin was given to the new patients on admission. Again, an amazing number of deaths from tetanus, in the United States, are due to wounds of the hands with toy-pistols. It is said that after the Fourth of July festivities in 1899, no less than 83 cases of tetanus were reported, 26 of them in and around New York. Almost all of them were due to gunshot wounds of the hand with toy-pistols: the unclean wad of the cartridge, made of refuse paper picked up in the streets, penetrates deep into the tissues of the hand, taking the germs of the disease with it, out of the reach of surgical disinfection. These cases of tetanus in the United States from toy-pistol wounds are so frequent, that immunisation has been recommended for them. The _Medical News_, 1st June 1901, has the following note:--"H. G. Wells states that tetanus is endemic in Chicago, the specific organism being present in the dirt of the streets. Every Fourth of July an epidemic occurs, because these bacilli are carried deeply into wounds before wads from blank cartridges.... The writer thinks that such cases should receive a prophylactic dose, say, 5 c.c. of tetanus-antitoxin, as soon as possible after the wound is first seen. It seems certain that if antitoxin prophylaxis were adopted, there would be no further Fourth of July epidemics, and this end would justify the means." Again, a man might receive a lacerated wound under conditions especially favourable to infection: he might tear his hand in a stable where horses had died of tetanus, or he might cut his finger while he was working at the disease in a pathological laboratory, or he might receive a poisoned arrow-wound out in Africa. In any such emergency, he could safeguard his life with a protective dose of antitoxin. It remains to be added, that the modern study of tetanus has brought into more general use the old rule that the wounded tissues in a severe case of tetanus should be at once excised. Before Nicolaier's work, while the theory still survived that the disease was due to ascending inflammation of a nerve, this rule was neither enforced nor explained. The results published during the last few years (_Medical Annual_, 1905-1906) seem to show that the antitoxin has neither gained nor lost ground as a remedy. It is, of course, used in conjunction with all other remedies. Perhaps, in a few years more, something better will be discovered. And that discovery, when it comes, will be, as it were, Nicolaier's gift. The whole study of the disease goes back straight to the rabbits inoculated in 1880-1884: neither is it possible that the disease should be further studied, without the help of bacteriology. VI RABIES Pasteur's study of rabies began in 1880; and the date of the first case treated--Joseph Meister, a shepherd-boy of Alsace--is July 1885. The first part of the work was spent in a prolonged search for the specific microbe of rabies. It was not found: its existence is a matter of inference, but not of observation.[24] In his earlier inoculations, Pasteur made use of the saliva of rabid animals; and M. Valléry-Radot tells the story, how Pasteur took him on one of his expeditions:-- "The rabid beast was in this case a huge bull-dog, foaming at the mouth and howling in his cage. All attempts to induce the animal to bite, and so infect one of the rabbits, failed. 'But we _must_,' said Pasteur, 'inoculate the rabbits with the saliva.' Accordingly a noose was made and thrown, the dog secured and dragged to the edge of the cage, and his jaws tied together. Choking with rage, the eyes bloodshot, and the body convulsed by a violent spasm, the animal was stretched on a table, and kept motionless, while Pasteur, leaning over his foaming head, sucked up into a narrow glass tube some drops of the saliva." [24] This sentence was written before the publication of Professor Negri's observations (see _Medical Annual_, 1906, p. 418). But these inoculations of saliva sometimes failed to produce the disease; and, when they succeeded, the incubation-period was wholly uncertain: it might be some months before the disease appeared. Thus Pasteur was led to use, instead of the saliva, an emulsion of the brain or spinal cord; because, as Dr. Duboué had suggested, the central nervous system is the chief seat, the _locus electionis_, of the virus of rabies. But these inoculations also were not always successful, nor did they give a definite incubation-period. Therefore he followed with rabies the method that he had followed with anthrax. As he had cultivated the virus of anthrax, by putting it where its development could be watched and controlled, so he must put the virus of rabies in the place of its choice. It has a selective action on the cells of the central nervous system, a sort of affinity with them; they are, as it were, the natural home of rabies, the proper nutrient medium for the virus: therefore the virus must be inoculated not under the skin, but under the skull. These sub-dural inoculations were the turning-point of Pasteur's discovery. The first inoculation was made by M. Roux:-- "Next day, when I informed Pasteur that the intracranial inoculation offered no difficulty, he was moved with pity for the dog. 'Poor beast, his brain is doubtless injured: he must be paralysed.' Without reply I went down to the basement to fetch it, and let it come into the laboratory. Pasteur did not like dogs, but when he saw this one, full of life, inquisitively rummaging about in all directions, he exhibited the greatest delight, and lavished most charming words upon it." Henceforth all uncertainty was at an end, and the way was clear ahead: Pasteur had now to deal with a virus that had a definite period of incubation, and a suitable medium for development. The central nervous system was to the virus of rabies what the test-tube was to the virus of fowl-cholera or anthrax. As he had controlled these diseases, had turned them this way and that, attenuated and intensified them, so he could control rabies. By transmitting it through a series of rabbits, by sub-dural inoculation of each rabbit with a minute quantity of nerve-tissue from the rabbit that had died before it, he was able to intensify the virus, to shorten its period of incubation, to fix it at six days. Thus he obtained a virus of exact strength, a definite standard of virulence, _virus fixe_: the next rabbit inoculated would have the disease in six days, neither more nor less. As he was able to intensify the virus by transmission, so he was able to attenuate it by gradual drying of the tissues that contained it. The spinal cord, taken from a rabbit that has died of rabies, slowly loses virulence by simple drying. A cord dried for four days is less virulent than one that has been dried for three, and more virulent than one dried for five. A cord dried for a fortnight has lost all virulence: even a large dose of it will not produce the disease. By this method of drying, Pasteur was enabled to obtain the virus in all degrees of activity: he could always keep going one or more series of cords, of known and exactly graduated strengths, according to the length of time they had been dried--ranging from absolute non-virulence through every shade of virulence. And, as with fowl-cholera and anthrax, so with rabies; a virus which has been attenuated till it has been rendered innocuous, can yet confer immunity against its more virulent forms: just as vaccination can protect against smallpox. A man, bitten by a rabid animal, has at least some weeks of respite before the disease can break out; and, during that time of respite, he can be immunised against the disease, while it is still dormant: he begins with a dose of virus attenuated past all power of doing harm, and advances day by day to more active doses, guarded each day by the dose of the day before, till he has manufactured within himself enough antitoxin to make him proof against any outbreak of the disease. The cords used for treatment are removed from the bodies of the rabbits, by an aseptic method, and are cut into lengths and hung in glass jars, with some chloride of calcium in them, for drying. The jars are dated, and then kept in glass cases in a dark room at a constant temperature. To make sure that the cords are aseptic, a small portion of each cord is sown on nutrient jelly in a test-tube, and watched, to see that no bacteria occur in the tube. For each injection, a certain small quantity of cord is rubbed-up in sterilised fluid; and these subcutaneous injections give no pain or malaise worth considering. Of course, the treatment is adjusted to the gravity of the case. A bite through naked skin is more grave than a bite through clothing; and bites on the head or face, and wolf-bites, are worst of all. The number and character of the scars are also taken into account. An excellent description of the treatment, by a patient, was published in the _Birmingham Medical Review_ of January 1898. It gives the following tables of treatment:-- 1. _Ordinary Treatment._ Day of Days of Drying Treatment. of Cord. 1 14 and 13 2 12 and 11 3 10 and 9 4 8 and 7 5 6 6 6 7 5 8 4 9 (1/2 dose) 3 10 (full dose) 5 11 5 12 4 13 4 14 (1/2 dose) 3 15 (full dose) 3 2. _Cases of Moderate Gravity._ Same treatment, up to 13th day. Day of Days of Drying Treatment. of Cord. 14 3 15 5 16 4 17 (1/2 dose) 3 18 (full dose) 3 3. _Grave Cases._ Same treatment, up to 10th day. Day of Days of Drying Treatment. of Cord. 11 4 12 3 13 5 14 5 15 4 16 4 17 (1/2 dose) 3 18 (full dose) 3 19 5 20 3 21 4 22 3 4. _Very Grave Cases._ Same treatment as 3, and in addition. Day of Days of Drying Treatment. of Cord. 23 5 24 4 25 (1/2 dose) 3 26 (full dose) 3 Furious criticism, unbelief, and flagrant misstatement of facts began at once, and lasted more than two years. Of Pasteur's opponents, the chief was M. Peter, who besought the Académie des Sciences, about once a week, that they should close Pasteur's laboratory, because he was not preventing hydrophobia but producing it. The value of M. Peter's judgment may be estimated by what he had said, a few years earlier, about bacteriology in general--"I do not much believe in that invasion of parasites which threatens us like an eleventh plague of Egypt. After so many laborious researches, nothing will be changed in medicine, there will only be a few more microbes. M. Pasteur's excuse is that he is a chemist, who has tried, out of a wish to be useful, to reform medicine, to which he is a complete stranger." But it does not matter what was said twenty years ago. In England, the Report of the 1886 Committee, and the Mansion House meeting in July 1889, mark the decline and fall of all intelligent opposition to the work. Among so many thousand cases, during so many years, it would be a miracle indeed if not a single case had failed or gone amiss; but we are concerned here with the thousands. Take, to begin with, four reports from Athens, Palermo, Rio, and Paris. It is to be noted that the patients, alike at Paris and at other Institutes, are divided into three classes:-- "A. Bitten by animals proved to have been rabid by the development of rabies in other animals inoculated from them. "B. Bitten by animals proved to have been rabid by dissection of their bodies by veterinary surgeons. "C. Bitten by animals suspected to have been rabid." It is to be noted also, as a fact proved beyond doubt, that the full benefit of the treatment is not obtained at once; the highest degree of immunity is reached about a fortnight after the discontinuance of the treatment. Those few cases, therefore, where hydrophobia has occurred, not only in spite of treatment, but within a fortnight of the last day of treatment, are counted as cases where the treatment came too late. Finally, what was the risk from the bite of a rabid animal, in the days before 1885? It is a matter of guess-work. One writer, and one only, guessed it at 5 per cent.; another guessed it at 55, and a third came to the safe conclusion that it was "somewhere between these limits." Leblanc, who is probably the best guide, put it at 16; and Pasteur himself put it between 15 and 20. But suppose it were only 10; that, before Pasteur, out of every 100 men bitten by rabid animals, 90 would escape and only 10 would die of hydrophobia; then take this fact, that in one year, at one Institute alone, there were 142 patients in class A, bitten by animals that were proved, by the unanswerable test of inoculation, to have been rabid; and 1 death. And every year the same thing; and in all the twelve years together, 2872 such cases (A) and 20 deaths--a mortality not of 10 per cent., but of less than 1 per cent. 1. _Athens_ The _Annales de l'Institut Pasteur_, June 1898, contain Dr. Pampoukis' report of three years' work at the Hellenic Institute, from August 1894 to December 1897. During this period 797 cases were treated--590 male and 207 female. The animals that bit them were--dogs, 732; cats, 34; wolf, 1; other animals, 13; and the 17 other patients had been exposed to infection from the saliva of hydrophobic patients. Of the 797 cases, 245 were of class A, 112 B, and 440 C. "Among the 797 persons treated, there are 2 deaths, one in class B and the other in class C. Thus the mortality has been 0.25 per cent. Besides these 2 who died of rabies there are 5 more, in whom the first signs of rabies showed themselves in less than fifteen days after the last inoculation. "Finally, beside these 797 cases, there is 1 other case, bitten by a wolf, in which the treatment failed. If we reckon this last case in the statistics of mortality, we have 3 deaths in 798 cases = 0.37 per cent. "Beside these 798 cases treated at the Institute, there have been others that have not undergone the antirabic treatment, having trusted the assurances of those who are called in Greece _empirics_. Among these non-treated cases there are 40 who have died of rabies." 2. _Palermo_ The _Annales_ for April 1896 give the report by Dr. de Blasi and Dr. Russo-Travali of the work of the Municipal Institute at Palermo during 8-1/2 years, from March 1887 to December 1895. The number of cases was 2221; in 1240 (class A), the animals were proved to have been rabid by the result of inoculations; in 981, there was reason to suspect rabies. "Setting aside 5 patients who died during the course of the treatment, and 5 others who died less than fifteen days after the end of the treatment, we have had to deplore only 9 failures = 0.4 per cent. Even if we count against ourselves the 10 other cases, the mortality is still only 0.85." 3. _Rio de Janeiro_ The _Annales_ for August 1898 give Dr. Ferreira's report of ten years' work (February 1888 to April 1898) at the Pasteur Institute at Rio. The number of cases treated was 2647, of whom 1987 were male and 660 female. Beside these 2647 there were 1234 who were not treated, because it was ascertained that they were in no danger of rabies; 3 who were brought to the Institute, already suffering from the disease; and 59 who refused treatment. Of the 2647 persons treated, 10 had pricked their hands at work in the laboratory, 3 had exposed chance scratches on their hands to the saliva of rabid animals, and 1 had been bitten by a rabid patient. Of the rest, 1886 had been bitten on the bare skin, and 747 through clothing. In 236 cases the rabies of the animal had been proved by inoculation. In 1173 it had been recognised by the signs of the disease. In 1238 there was good reason to suspect that the animal had been rabid. Of the 2647 patients, in 30 cases the treatment was stopped, because the animals were at last traced, after treatment was begun, and were found not to be rabid. In 65 cases the patients, after treatment was begun, refused to go on with it, and 3 of them died of rabies. In 6 cases rabies developed during treatment; 5 of them had been very badly bitten about the head, and 1 did not come for treatment till the twenty-first day after the bite, and was attacked by rabies two days later. And 5 cases died of other maladies that had nothing to do with rabies. Setting aside these 106 cases, there remain 2541 cases, with 20 deaths = 0.78 per cent. But, of these 20 deaths, 9 occurred within fifteen days of the end of treatment, before protection was fully established. If these 9 deaths be excluded, the figures stand at 2532 cases, with 11 deaths = 0.43 per cent. 4. _Paris_ Dr. Pottevin's report on the work of the Pasteur Institute (Paris) during 1897 (_Annales_, April 1898) must be given word for word, without abbreviation. I During 1897, 1521 patients received the anti-treatment at the Pasteur Institute: 8 died of rabies. The notes of their cases will be found at the end of this paper. If we exclude 2 of these 8 cases--the cases of Heniquet and Morin, where death occurred before it was possible for the vaccinations to produce their effect--the results of the vaccinations in 1897 are Patients treated 1519 Deaths 6 Mortality per cent. 0.39 In the following table these figures are compared with those of preceding years:-- +-------+----------+---------+-----------+ | Year. | Patients | Deaths. | Mortality | | | treated. | | per cent. | +-------+----------+---------+-----------+ | 1886 | 2671 | 25 | 0.94 | | 1887 | 1770 | 14 | 0.79 | | 1888 | 1622 | 9 | 0.55 | | 1889 | 1830 | 7 | 0.38 | | 1890 | 1540 | 5 | 0.32 | | 1891 | 1559 | 4 | 0.25 | | 1892 | 1790 | 4 | 0.22 | | 1893 | 1648 | 6 | 0.36 | | 1894 | 1387 | 7 | 0.50 | | 1895 | 1520 | 5 | 0.33 | | 1896 | 1308 | 4 | 0.30 | | 1897 | 1521 | 6 | 0.39 | +-------+----------+---------+-----------+ II Patients treated at the Pasteur Institute are divided into three classes, as follows:-- A. The rabies of the animal was proved by experiment, by the development of rabies in animals inoculated with its bulb (the upper end of the spinal cord).[25] [25] It is satisfactory to know that rabbits affected with rabies do not suffer in the same way as dogs and some other animals, but become subject to a painless kind of paralysis. B. The rabies of the animal was proved by veterinary examination (dissection of its body). C. The animal was suspected of rabies. We give here the patients treated in 1897, under these three classes:-- +------------------+---------------+---------------+---------------+ | BITES OF THE | BITES ON THE | BITES OF THE | TOTAL. | | HEAD. | HANDS. | LIMBS. | | +--+-----+---+-----+-----+---+-----+-----+---+-----+-----+---+-----+ | | P | | M p | P | | M p | P | | M p | P | | M p | | | a | D | o e | a | D | o e | a | D | o e | a | D | o e | | | t | e | r r | t | e | r r | t | e | r r | t | e | r r | | | i | a | t | i | a | t | i | a | t | i | a | t | | | e | t | a c | e | t | a c | e | t | a c | e | t | a c | | | n | h | l e | n | h | l e | n | h | l e | n | h | l e | | | t | s | i n | t | s | i n | t | s | i n | t | s | i n | | | s | . | t t | s | . | t t | s | . | t t | s | . | t t | | | . | | y . | . | | y . | . | | y . | . | | y . | +--+-----+---+-----+-----+---+-----+-----+---+-----+-----+---+-----+ | A| 15 | 0 | 0 | 81 | 0 | 0 | 46 | 1 | 2.1 | 142 | 1 | 0.7 | | B| 106 | 0 | 0 | 539 | 4 | 0.74| 273 | 1 | 0.4 | 918 | 5 | 0.65| | C| 30 | 0 | 0 | 244 | 0 | 0 | 187 | 0 | 0 | 461 | 0 | 0 | +--+-----+---+-----+-----+---+-----+-----+---+-----+-----+---+-----+ | | 151 | 0 | 0 | 864 | 4 | 0.46| 506 | 2 | 0.4 |1521 | 6 | 0.39| +--+-----+---+-----+-----+---+-----+-----+---+-----+-----+---+-----+ The following tables, giving the results obtained since the vaccinations were first used, show that the gravity of the bites varies with their position on the body, and that the mortality is always below 1 per cent. among patients bitten by dogs undoubtedly rabid:-- +-------------------+---------+-------+----------+ | |Patients.|Deaths.|Mortality.| +-------------------+---------+-------+----------+ |Bites of the Head | 1,759 | 21 | 1.1 | |Bites of the Hands | 11,118 | 53 | 0.47 | |Bites of the Limbs | 7,289 | 22 | 0.30 | +-------------------+---------+-------+----------+ | | 20,166 | 96 | 0.46 | +-------------------+---------+-------+----------+ +---+---------+-------+----------+ | |Patients.|Deaths.|Mortality.| +---+---------+-------+----------+ | A | 2,872 | 20 | 0.69 | | B | 12,547 | 61 | 0.48 | | C | 4,747 | 15 | 0.31 | +---+---------+-------+----------+ | | 20,166 | 96 | 0.46 | +---+---------+-------+----------+ III In regard to their nationality, the 1521 patients treated at the Pasteur Institute in 1897 were as follows:-- Germany 8 England 83 Belgium 14 Egypt 2 United States 1 Greece 1 India 33 Switzerland 33 That is, 175 foreigners and 1346 French. IV Notes of the eight cases where the treatment failed:-- 1. Camille Bourg, 26. Bitten 11th April; treated at the Pasteur Institute, 13th to 30th April; died of rabies at the Lariboisière Hospital, 26th May. Six penetrating bites on the ball of the left thumb. The dog was examined by M. Grenot, a veterinary surgeon at Paris, and the dissection gave evidence of rabies. Another person bitten and treated at the same time as Bourg is now in good health. 2. Louis Fiquet, 23. Bitten 22nd April; treated at the Pasteur Institute, 23rd April to 10th May; died of rabies at the Necker Hospital, 4th June. Five bites, two of them deep, round the right thumb. They had been cauterised five hours after infliction. The dog was examined by M. Caussé, a veterinary surgeon at Boulogne, and the dissection gave evidence of rabies. Another person bitten at the same time as Fiquet is now in good health. 3. Annette Beaufort, 19. Licked on the hands, which were chapped, on 15th April. The dog was killed next day, examined, and declared to have been rabid by M. Lachmann, a veterinary surgeon at Saint-Étienne. Treated at the Pasteur Institute, 20th April to 7th May. Died of rabies 14th October. Two other persons bitten by the same dog and treated at the Pasteur Institute are now in good health. 4. Julien Heniquet, 53. Bitten 11th March, by a dog that M. Jenvresse, veterinary surgeon at Beaumont-sur-Oise, declared after dissection to have been rabid. One bite had torn the lower lip, the wound had been sutured; three other wounds on the nose. The wounds had not been cauterised. Treated at the Pasteur Institute, 18th May to 5th June. First symptoms of rabies showed themselves 4th June, before the treatment was finished; died 7th June. As the disease had its onset during the course of the inoculations, this case should be excluded from the number of those who died of rabies after treatment. 5. Germain Segond, 7. Penetrating bite on the bare right fore-arm, 23rd May. Cauterised an hour later with a red-hot iron. Treated 26th May to 9th June; died of rabies 22nd July. The dog's bulb had been sent to the Pasteur Institute. A guinea-pig inoculated in the eye 26th May was seized with rabies 10th September. 6. Suzanne Richard, 8. Bitten 12th June on the left leg by a dog, found on dissection to have been rabid by M. Touret, veterinary surgeon at Sannois. The bite, penetrating 3 cm. long, had been sutured; it had been made through a cotton stocking, and had been cauterised in half-an-hour. Treated 13th to 30th June; died of rabies 2nd August. (Notes from M. le Dr. Margny, at Sannois.) 7. Joseph Vaudale, 33. Bitten on the left hand, 8th August. Six penetrating bites on the back of the hand; had not been cauterised. The dog was declared rabid by M. Verraert, veterinary surgeon at Ostend. Treated at the Pasteur Institute, 11th to 28th August; died of rabies 27th September. 8. Paul Morin, 38. Bitten 24th August on the left cheek, a single bite, 2 cm. long; no cauterisation. The dog was sent to the Alfort School, 25th August, and found to be rabid. Treated at the Pasteur Institute, 26th August to 15th September. Died of rabies some days after the end of treatment (three weeks after the bite, says a note sent to us). The interval between the end of the treatment and the onset of the disease being less than fourteen days, Morin must not be counted in the number of patients inoculated under conditions which permit successful inoculation. * * * * * We hardly need follow the work of the remaining years. The figures are as follows:-- +-------+----------+---------+-----------+ | Year. | Patients | Deaths. | Mortality | | | treated. | | per cent. | +-------+----------+---------+-----------+ | 1898 | 1465 | 3 | 0.2 | | 1899 | 1614 | 4 | 0.25 | | 1900 | 1420 | 4 | 0.28 | | 1901 | 1318 | 5 | 0.38 | | 1902 | 1105 | 2 | 0.18 | | 1903 | 628 | 2 | 0.32 | | 1904 | 755 | 3 | 0.39 | +-------+----------+---------+-----------+ The falling off in the number of patients at the Paris Institute is related to the establishment of similar Institutes at Lyon, Marseilles, Bordeaux, Lille, and Montpellier. But is it not possible that a patient, after treatment at the Paris Institute, should die at home of rabies, and his death not be notified to the Institute? The answer is, that the Institute is very careful, so far as possible, to keep in touch with its old patients. For instance, in 1903, it recorded the case of a carpenter in a Welsh village, who had died of rabies nearly two years after treatment. And, of course, an Institute patient, wherever he was, would be of interest to his neighbours: and a death from rabies would excite attention, and would hardly fail to be reported. It is not impossible that some sort of intensive modification of Pasteur's treatment may be found, not for the prevention, but for the cure of hydrophobia; and two successful cases of this kind have been reported in the _Annales_ of the Paris Institute. Apart from this faint hope, the _cure_ of hydrophobia is where it was in the days of the "Tonquin medicine" and the "Tanjore pills." VII CHOLERA The study of cholera was the hardest of all the hard labours of bacteriology; it took years of work in all parts of the world, and the difficulty and disappointments over it are past all telling. Koch's discovery of the comma-bacillus (1883) raised a thousand questions that were solved only by infinite patience, international unity for science, and incessant research; and the Hamburg epidemic (1892) marks the time when the comma-bacillus was at last recognised as the cause of cholera. A mere list of the men who did the work would fill page after page; it was bacteriology _in excelsis_, often dangerous,[26] and always laborious. [26] "In order to prove that this _vibrio_ is the cause of Asiatic cholera, several tests upon themselves have been voluntarily made by investigators in laboratories. These were carried out in Munich and in Paris. The results to the experimenters were sufficiently severe to indicate positively the pathogenic character of the spirillum, and its capacity to produce cholera-like infections. Such experimentation is, of course, to be deprecated; indeed, the occurrence of accidental laboratory infections, one of which ended fatally, furnished the necessary final proof of the specificity of the cholera _vibrio_, and rendered unnecessary any exposure to the risks belonging to voluntary inoculation." (Dr. Flexner, Stedman's _Twentieth Century Practice_, vol. xix., 1900.) There is the same heroic note in the story of the preventive treatment of cholera by Haffkine's method; one of the men in whom Pasteur seems to live again. He began in 1889, under Pasteur's guidance, to study the immunisation of animals against the cholera-bacillus. Other men, of course, were working on the same lines--Pfeiffer, Brieger, Metchnikoff, Fischer, Gamaleïa, Klein, Wassermann, and many more--and by 1892 the immunisation of animals was proved up to the hilt. Then came the advance from animals to men, from laboratories to Indian cities, villages, and cantonments; and here the honour is Haffkine's, and his alone. Ferran's inoculations (Spain, 1885) had failed. Haffkine, having tested his method on himself and his friends, went to India, with a commendatory letter from the British Government:-- "Researches on cholera, with special reference to inoculation, were undertaken and carried on in my laboratory, in the Pasteur Institute in Paris, between 1889 and 1893. The experiments resulted in the elaboration of the present method, which when tried on animals was found to render them resistant against every form of cholera-poisoning otherwise fatal to them. "The physiological and pathological effect on man was then studied on some sixty persons, mostly medical and scientific men interested in the solution of the problem. The effect was found to be harmless to health. The next step was to transfer the operations to the East." (Haffkine's _Report to the Government of India_, 1895.) He reached Calcutta in March 1893, and at the request of Mr. Hankin[27] was invited to Agra; here, in April, he vaccinated over 900 persons, including many English officers. From Agra to Aligarh; and from Aligarh he was asked to more places than he could visit. In 1895 his health failed, and no wonder; and he came back to Europe for a short time:-- "My actual work in India lasted twenty-nine months, between the beginning of April 1893 and the end of July 1895. During this period the anti-cholera vaccination has been applied to 294 British officers, 3206 British soldiers, 6629 native soldiers, 869 civil Europeans, 125 Eurasians, and 31,056 natives of India. The inoculated people belonged to 98 localities in the North-West Provinces and Oudh, in the Punjab, in Lower Bengal and Behar, in the Brahmaputra Valley, and in Lower Assam. No official pressure has been brought on the population, and only those have been vaccinated who could be induced to do so by free persuasion. In every locality, efforts were made to apply the operation on parts of large bodies of people living together under identical conditions, in order to compare their resistance in outbreaks of cholera with that of non-inoculated people belonging to the same unit of population. This object has been obtained in 64 British and native regiments, in 9 gaols, in 45 tea-estates, in the fixed agricultural population of the villages parallel to Hardwâr pilgrim road, in the _bustees_ of Calcutta, in a certain number of boarding-schools, where the parents agreed to the inoculation of their children, in orphanages, etc. The vast majority of inoculated people lived thus under direct observation of the sanitary and medical authorities of India." (Haffkine, Lecture in London. _British Medical Journal_, 21st Dec. 1895.) [27] Mr. Hankin, whose name is had in remembrance by Cambridge men, is Chemical Examiner and Bacteriologist to the North-West Provinces and Oudh, and to the Central Provinces. Altogether, upwards of 70,000 injections on 42,179 people--_without having to record a single instance of mishap or accident of any description produced by our vaccines_. Consider the colossal difficulties of this new treatment: the frequent running short of the vaccine, preventing a second injection; the absolute necessity, at first, of using very small doses of a weak vaccine, lest one disaster should occur; the impossibility of avoiding, now and again, some loss of strength in the vaccine; the impossibility of knowing how long the protection would last. Surely in all science there is nothing to beat this first voyage of adventure single-handed to fight the cholera in India. Later than Haffkine's 1895 report, we have Dr. Simpson's 1896 report: "_Two Years of Anti-choleraic Inoculations in Calcutta._ W. J. Simpson, M.D., M.R.C.P., D.P.H., Health Officer, Calcutta." The date of this report is 8th July 1896; and it gives not only the Calcutta results, but all that are of any use for exact judgment:[28]-- "The results of Calcutta are fully confirmed by those obtained in other parts of India, wherever it was possible to make all the necessary observations with precision, and wherever the cases were sufficiently numerous to show the effect of the inoculation. "Outside Calcutta, since the commencement of the inoculations in India in April 1893, opportunities for an exact comparison of the respective powers of resistance against cholera of inoculated and non-inoculated persons presented themselves; (1) in Lucknow, in the East Lancashire Regiment; (2) in Gaya, in the jail; (3) in Cachar, among the tea-garden coolies; (4) in Margherita, among coolies of the Assam-Burmah Railway Survey; (5) in Durbhanga, in the jail; (6) in the coolie camp at Bilaspur; (7) in Serampur, among the general population." [28] For a summary of this report, see the _Lancet_, 8th August 1896. For more recent results, see Surgeon-Captain Vaughan and Assistant-Surgeon Mukerji, in the thirtieth annual report of the Sanitary Commissioner for Bengal (1897). Also the note published by Surgeon-Captain Nott, in the _Indian Medical Gazette_, May 1898. Here, then, in this 1896 report, are all the results that give an answer to the question, What will happen when cholera breaks out among a number of people living under the same conditions, of whom some have received preventive treatment, and the rest have been left to Nature? I. _Calcutta_ (1894-1896) "The number of people inoculated during the period under review was 7690; of these, 5853 are Hindus, 1476 Mahomedans, and 361 other classes.... Considering that the system is a new one, that the inoculations are purely voluntary, and everything connected with them has to be explained before the confidence of the people can be obtained, and considering how long new ideas are in taking root among the general population--and in this case it is not merely the acceptance of an idea, but such faith in it as to consent to submit to an operation--the number is certainly satisfactory for a beginning. The present problem can be compared with the introduction of vaccination against smallpox into Calcutta. It took 25 years before the number of vaccinations reached an average of 2000; whereas the inoculations against cholera have in two years nearly doubled that average. This is a proof that, in spite of the difficulties which every new movement naturally has to meet with, there are large numbers of people anxious to avail themselves of the protective effect of the inoculations. "Although all sorts and conditions of individuals, weak and strong, sickly and healthy, young and old, well nourished and badly nourished, and often persons suffering from chronic diseases, have been inoculated, in every instance, without exception, the inoculations have proved perfectly harmless. "The investigations on the effect of the inoculation are made exclusively in those houses in which cholera has actually occurred, the object being to ascertain and compare the incidence of cholera on the inoculated and not inoculated in those houses in which inoculations had been previously carried out. _For this purpose, affected houses in which inoculations have not been performed, and inoculated houses in which cholera has not appeared, are excluded._" Nature gave a demonstration in 77 houses. In one house, and one only, all the household had been inoculated; in 76, inoculated and non-inoculated were living together; but of these 76 houses, 6 are excluded from the table of results, because the inoculated in them were so few--less than one-tenth of the household--that their escape from cholera might be called chance. The cholera came, and left behind it this fact:-- 654 uninoculated individuals had 71 deaths = 10.86 per cent. 402 inoculated in the same households had 12 deaths = 2.99 per cent. If we add the 6 houses which Dr. Simpson excludes, we find that in 77 houses there were 89 deaths from cholera, 77 being among the uninoculated and 12 among the inoculated. Moreover, of these 12 deaths, 5 occurred during the first five days after inoculation--that is to say, during the period in which the protective influence of the vaccine was still incomplete. _Then came a period of more than a year, during which the uninoculated had 42 deaths, and the inoculated had one death._ The remaining 6 of the 12 deaths occurred more than a year after inoculation, and 5 of these 6 had received only one inoculation of the weak vaccine that was used early in 1894. Take a good instance that came at the very beginning of the work:-- "A local epidemic took place around two tanks in Kattal Began _bustee_, ward 19, occupied by about 200 people. In this _bustee_, about the end of March, 2 fatal cases of cholera and 2 cases of choleraic diarrhoea occurred. The outbreak led to the inoculation of 116 persons in the _bustee_ out of the 200. Since then, 9 cases of cholera, of which 7 were fatal, and 1 case of choleraic diarrhoea have appeared in the _bustee_, and it is a very extraordinary fact that all these 10 cases of cholera have occurred exclusively among the uninoculated portion of the inhabitants, which, as stated, forms the minority in the _bustee_; while none of the inoculated have been affected." (_Cholera in Calcutta in 1894._ W. J. Simpson.) 2. _Lucknow_ (1893) The story of the outbreak of cholera in the East Lancashire Regiment must be read carefully:-- "Rumour magnified the events connected with this outbreak, and distorted the facts connected with the inoculations; and as a result, the current of public opinion, which had previously been in favour of inoculation, set in strongly in the opposite direction. The advocates of anti-choleraic inoculations were abused in no particularly measured terms, and the inoculations were held up to be the source of every possible evil and danger ... of the most loathsome diseases, and of every ill which man is heir to. The distrust engendered by these misrepresentations and fulminations was, however, only of a temporary nature; and when the exact circumstances came to be known and understood, the confidence created by the Calcutta experience began to be considerably restored. Inoculations were performed in May 1893, in the East Lancashire, Royal Irish, 16th Lancers, 7th Bengal Infantry, 7th Bengal Cavalry, and general populations in the Civil Lines. In 1894, cholera appeared among the native population of Lucknow, in the form of an epidemic distinguished by its extreme virulence, patients succumbing in the course of a few hours. It is stated that the epidemic was of a most malignant type. In the latter part of July it entered the cantonments, and attacked the East Lancashire, almost exclusively confining its ravages to that regiment." In the East Lancashire, 185 men were inoculated in May 1893. From the statistical returns obtained from the military authorities at Lucknow, it appears that at the time of the outbreak, in July 1894, the strength of the men, including those in hospital, was 773; and of these, 133 had been inoculated, as recorded in the inoculation register, and 640 had not been inoculated. The following table shows the total number of attacks and deaths in not inoculated and inoculated:-- +---------------------+-------------+------------+ | | Attacks. | Deaths. | +---------------------+-------------+------------+ | | Per cent. | Per cent. | | Non-inoculated, 640 | 120 = 18.75 | 79 = 12.34 | | Inoculated, 133 | 18 = 13.53 | 13 = 9.7 | +---------------------+-------------+------------+ The men were moved into camp; but this movement seemed only to make things worse: "the epidemic in the camp appears to have been twice as severe as in the cantonment."[29] [29] "The moving into camp, notwithstanding this example, is all the same an excellent measure of defence, and would with reason be adopted in every outbreak." (Simpson, _loc. cit._) Lucknow came so early in the work of inoculation, that weak vaccines were used in small doses. The cholera, when it broke out, was "of a most malignant type, senior medical officers of long experience in the country stating that such a virulent cholera had not been seen by them for very many years past." More than a year had elapsed between the inoculations and the outbreak of the cholera. It is no wonder that the regiment was not well protected:-- "The small amount of protection which the inoculations afforded in this case may have depended on the mild effects which the injections produced on the men at the time of the operation in 1893, in comparison with the severity of the epidemic which attacked the regiment. It is recorded in the Lucknow Inoculation Registers that only in two men, out of the 185 inoculated in 1893, a marked febrile reaction was obtained; in 77 individuals the vaccinal fever was only slight, while in 66 there was no reaction: an effect which was due to the weakness of the vaccines procurable at that period of work, and to the small doses used. The influence of the vaccines was possibly further reduced, at the time of the epidemic, by a lapse of fourteen to fifteen months." (Haffkine, 1895 Report.) 3. _Gaya Jail_ On 9th July 1894, an outbreak of cholera occurred in the Gaya jail, and by 18th June there had been 6 cases and 5 deaths. On that day and the next day, 215 prisoners were inoculated. The average number of the prisoners during the outbreak was 207 inoculated, and 202 not inoculated. Surgeon-Major Macrae, superintendent of the jail, reports:-- "The inoculations being purely voluntary, no selection of prisoners was possible, but all classes of the jail were represented--male and female, old and young, habituals and less frequent offenders, strong and weakly, convalescent and even hospital patients sent their representatives; no difference of any kind was made between inoculated and non-inoculated; they were under absolutely identical conditions as regards food, water, accommodation, etc., in fact in every possible respect." Of course, the best results could hardly be obtained, because the cholera was already at work: it took about ten days for the 1894 vaccine to produce its full effect; and two inoculations were generally made, one five days after the other. This gradual action of the vaccine is well shown in Dr. Simpson's table:-- +-------------------------+------------------+------------------+ | | NON-INOCULATED, | INOCULATED, | | | 202. | 207. | +-------------------------+------------------+------------------+ | | Cases. | Deaths. | Cases. | Deaths. | +-------------------------+--------+---------+--------+---------+ | During 5 days after 1st | 7 | 5 | 5 | 4 | | inoculation | | | | | | During 3 days after 2nd | 5 | 3 | 3 | 1 | | inoculation | | | | | | After 3 days after 2nd | 8 | 2 | 0 | 0 | | inoculation | | | | | +-------------------------+--------+---------+--------+---------+ Haffkine's comment on these figures must be noted here:-- "In the Gaya jail, the inoculations were _for the first time_ applied _in a prevalent epidemic_, and _very weak doses_ of a relatively weak vaccine were used.... Far higher results have been obtained by an application of stronger doses. In the _bustees_ situated round the tanks in Calcutta, where cholera exists in a permanent state, the disease occurred in 36 houses with inoculated people. In each of these houses there was one part of the family inoculated and another not. The observations were continued for 459 days, with the following results:-- During the first period of 5 days, subsequent to the inoculation with first vaccine, cholera occurred in 8 houses. 75 non-inoculated had 5 cases, with 3 deaths. 52 inoculated had 3 cases, with 3 deaths. During the second period of 5 days, subsequent to the second inoculation, cholera occurred in 2 houses. 8 non-inoculated had 2 cases, with 2 deaths. 17 inoculated had no cases. _After the 10 days necessary for the preventive treatment had expired, and up to the 459th day, the disease visited 26 houses._ _263 non-inoculated had 38 cases, with 34 deaths._ _137 inoculated had 1 case, with 1 death, in a child that had not been brought up for the second inoculation."_ 4. _Assam-Burmah Railway_ For a good instance of lives saved even during an outbreak, take the Assam-Burmah Railway coolies:-- _"Three hundred and fifty[30] Khassia Hill coolies had been collected for the survey party of the Assam-Burmah Railway, and put under the escort of a detachment of Goorkhas, when cholera broke out amongst them. The largest part of the coolies immediately submitted to the preventive inoculation, the rest remained uninoculated. The result was that _among the not-inoculated minority there were 34 cases, with 30 deaths; whereas the inoculated had 4 fatal cases_." (Haffkine, 1895, Lecture in London.)_ [30] The exact number is 355, of whom 196 were inoculated; the coolies numbered 343, and the Goorkhas 12. (See Dr. Simpson's 1896 Report.) 5. _Durbhanga Jail_ (1896) The figures in this instance are small: but Surgeon-Captain E. Harold Brown's report is very pleasant reading. Cholera broke out in the jail on 31st March 1896, and by 9th April there had been 8 cases. Next day, 172 prisoners were moved into camp 12 miles away; and 53 were left behind, the sick in the jail hospital, the patients in the cholera huts, with their attendants, the old and infirm, and a few cooks and sweepers. That day, 3 cases occurred in the camp, and 1 in the jail; and on the 11th, at 2 and 4 A.M., 2 more cases were reported in camp. At 7.30 A.M., Haffkine and Dr. Green came to the camp:-- "The prisoners were spoken to on the subject, and seemed to be pleased with the idea, the word _tika_ (inoculation), which was familiar to them from its association with smallpox, appearing to appeal to them. They were accordingly arranged in four rows facing the tent, in front of which Dr. Haffkine was about to commence operations. I was the first subject to be inoculated; and after me the jailor, assistant jailor, hospital assistant, and three warders. The first prisoner in the front rank was next brought up and submitted cheerfully; after which, every alternate man was taken, so that no selection of cases was made, until one-half of the total number were inoculated. Those who had not been inoculated were far from pleased at having been passed over; and, to our surprise, they rose almost to a man, and begged to be inoculated; nor were they satisfied when told that the medicine was exhausted." The dose administered on this occasion (11th April 1896) was stronger than the Gaya jail dose (18th July 1894): it acted in a few hours, and the reaction was well marked. "There were fresh cases of cholera that day at 12 (noon), 6, 7, and 7.30 P.M., and at midnight, all in those who had not been inoculated, and all terminating fatally, despite the greatest care and the most prompt and assiduous treatment. On the 12th two further cases occurred, both among the uninoculated, and both died; there being thus eight cases in succession, all from the men who were not inoculated, and all proving fatal." The inoculations were made at 7.30 A.M. Surgeon-Captain Brown had pain within half-an-hour, and fever in three hours, with temperature 104°, _but this was probably due to the fact that I was not able to rest_. The prisoners, of course, went to bed: they all reacted before 4 P.M., but did not have so much trouble over it. The last case was on the 15th. The outbreak was a bad type of cholera; out of 30 cases 24 died, some of them in 1-1/2 to 4 hours. "To summarise the combined results of the camp and the jail, we find that of a daily average of 99 non-inoculated there were 11 cases, all fatal = 11.11 per cent.; of 110 inoculated there were 5 cases, with 3 deaths = 2.73 per cent." 6. _Bilaspur and Serampur_ Here again the figures are small, but worth noting. In a coolie camp at Bilaspur (Central Provinces) 100 non-inoculated had 5 deaths, and 150 inoculated had 1 death. In Serampur, among the general population, 51 non-inoculated had 5 cases and 3 deaths, and 42 inoculated had 2 cases and 1 death. 7. _The Cachar Tea-Gardens_ (1895) This series of inoculations was begun in February 1895, for the protection of the coolies on various tea-estates. The results are excellent, and deal with large numbers.[31] The latest report from Dr. Arthur Powell, the Medical Officer, is quoted in Dr. Simpson's 1896 report:-- _At Kalain_-- 1079 not inoculated had 50 cases, with 30 deaths. 1250 inoculated--3 cases, with 2 deaths.[32] _At Kalaincherra_-- 685 not inoculated had 10 cases, with 7 deaths. 155 inoculated--no cases. _At Degubber_-- 254 not inoculated had 12 cases, with 10 deaths. 407 inoculated--5 cases, all recovered. _At Duna_-- 121 not inoculated had 4 cases, with 2 deaths. 29 inoculated--no cases. _At Sandura_-- 454 not inoculated had 2 cases, with 1 death. 51 inoculated--2 cases, with 1 death. _At Karkuri_-- 198 not inoculated had 15 cases, with 9 deaths. 443 inoculated--3 cases, with 1 death. _At Craig Park_-- 185 not inoculated had 1 fatal case. 46 inoculated--no cases. TOTAL. Not inoculated, 2976, with 94 cases and 60 deaths. Inoculated, 2381, with 13 cases and 4 deaths. [31] "As a field for testing the value of inoculation, the tea-factories of India possess many advantages. The labourers being under contract, the after-history of those inoculated is easily followed up. Each morning the adults are paraded for roll-call; and all sick must attend hospital, where a record is made of their disease and treatment." (Dr. Powell, _Lancet_, 13th July 1896.) [32] "It is unfortunate that neither of the fatal cases among the inoculated was seen by any medical man, not even an unqualified doctor Babu." Dr. Powell does not think, from what was told him, that one of them was cholera. To the preceding instances, which are rather old now, must be added the following more recent report, from the _Indian Medical Gazette_, September 1901:-- "We are glad to see, from a paragraph in the Report of the Sanitary Commissioner for Bengal (Major H. J. Dyson, I.M.S., F.R.C.S.), that an increased number of anti-cholera inoculations were performed during the year 1900. Assistant-Surgeon G. C. Mukerjee, who was in charge of this work, reports that in the Puralia Coolie Depot no less than 13,291 persons were inoculated against cholera, including over 1000 children. All these cases of inoculation were among labour emigrants proceeding to the tea-gardens of Assam and Cachar. The employers of labour are beginning to realise the value of cholera inoculation. It is unfortunately not always easy, or even possible, to follow up the after-history of persons inoculated; but Major Dyson has quoted a table, received from the Superintendent of Emigration, which shows the number of cases among the inoculated and the non-inoculated at Goalundo. From this table, it is seen that out of 1527 non-inoculated coolies, who passed through Goalundo, 33, or 2.09 per cent., got cholera; whereas of 873 inoculated coolies, only 2, or 0.2 per cent., were attacked by the disease; that is, the unprotected suffered about ten times as much as the inoculated. Assistant-Surgeon Mukerjee also reports that during his cold-weather tour he passed through some villages in the Manbhum district, in which he had practised inoculation the previous year: and, though there had been epidemics of cholera in them, the inoculated persons escaped. They came to him in numbers, stating that they owed their safety to the inoculation." Of course, the preventive treatment touches points only here and there on the map of India, with its 300,000,000 people. Probably it will never become so general in India as vaccination. Cholera in India recalls what Ambroise Paré, more than 400 years ago, wrote of the plague, "Here in Paris it is always with us." But, wherever preventive inoculation has been done, there it has done good. The _Medical Annual_ for 1905 contains an account of some preventive inoculations recently made during an epidemic in Japan. Among the inoculated, the attack-rate was much lower than among the uninoculated; and the mortality was 45.5 per cent., as against 75 per cent. Another most important result of the discovery of the cholera bacillus is its use in diagnosis. For example, if a case of suspected cholera is landed at a British port, the sanitary authority at once takes steps to ascertain whether the specific microbe is present; and, according to the answer given by bacteriology, either allows the patient to proceed on his journey, or adopts measures of isolation to prevent the spread of the disease to others. Thus, thanks to the insular position of Great Britain, this dreadful disease has for many years been prevented from invading her population. VIII PLAGUE The _bacillus pestis_ was discovered by Kitasato and Yersin, working independently, in 1894. Yersin's discovery was made at Hong Kong, whither the French Government had sent him to study plague: an excellent account of his work is given in the _Annales de l'Institut Pasteur_, September 1894. The first experiments in preventive inoculation, in animals, were made by Yersin, Calmette, and Borrel, working conjointly, in 1895. They found that it was possible to confer on animals a certain degree of immunity, by the hypodermic injection of dead cultures of the bacillus. These experiments were made on rabbits and guinea-pigs. Haffkine's fluid was first used on man in January 1897. It is a _bouillon_ containing no living bacilli, and nothing offensive to the religious beliefs of India.[33] He proved its efficacy on rabbits; and then, on 10th January 1897, inoculated himself with a large dose, four times as strong as the subsequent standard dose. A few days later, Lieut.-Col. Hatch, Principal of the Grant Medical College, Bombay, and other members of the College Staff, were inoculated. These first inoculations were described by Haffkine in a lecture (1901) at Poona:-- "In a short time, a number of the most authoritative physicians in Bombay, European and native, official medical officers and private practitioners, submitted themselves for inoculation. It is a matter of gratification to me to be able to quote, among these authorities, the Head of the Medical Service of the Presidency, Surgeon-General Bainbridge, who not only got himself inoculated, but inoculated also the members of his family. Previous to that, Surgeon-General Harvey, the able Director-General of the Indian Medical Service, submitted himself to inoculation in 1893 against cholera; and, in 1898, against plague. It was the example of these gentlemen, whose competence in the matter of health could not be disputed, that encouraged thousands of people, rich and poor, in Bombay and elsewhere, to come forward for inoculation. Thus his Excellency the Viceroy thought it right to tell you here, in Poona, that previous to his starting for the plague-stricken districts he and his staff had also undergone the prophylactic inoculation. In due course, mothers brought their children to be protected by the new 'vaccination.'" [33] It is said that the Jains object to inoculations on the grounds of religion; and one or two witnesses before the Plague Commission gave evidence to the same effect. But, at Bombay, the high-priest of a great religious community addressed a meeting of 5000 in favour of the new treatment; and the rush of suppliants for inoculation at Hubli and Gaday proves that there is no real religious difficulty. Doctors have been assaulted, as at Poona, so at Oporto; in neither case can we say _Tantum relligio potuit suadere malorum_. Within a few months, 8142 persons in or near Bombay were inoculated. It was not possible, in Bombay, during the rush of plague-work, to follow up every one of these 8142 persons. But there is reason to believe, making some allowance for oversights, that only 18 = 0.2 per cent. of them, were attacked during the epidemic; that, of these 18, only 2 died: and that these 2 died within twenty-four hours of inoculation, _i.e._, had the plague in them already at the time of inoculation. And, with regard to a small group of the inoculated, there are the following more definite facts. This group lived outside Bombay, across the harbour, in a village called Mora. The population of Mora, at the time of the epidemic, was estimated at less than 1000. Out of this number 429 were inoculated; which, if the population be reckoned at 1000 exactly, left 571 uninoculated. Among the 429 inoculated, there were 7 cases of plague, with no deaths: among the uninoculated there were 26 cases, with 24 deaths. Just a week after Haffkine had informed the Indian Government that he had tested his fluid on himself, plague broke out in the Byculla House of Correction, Bombay, on 23rd January 1897. Between the 23rd and the afternoon of the 30th, there were 14 cases, with 7 deaths. On the afternoon of the 30th, 152 prisoners were inoculated, and 172 were left uninoculated. The outbreak ceased on 7th February. The figures, as corrected by the Plague Commission, are, among the inoculated, 1 case, which recovered; among the uninoculated, 7 cases, with 2 deaths. For a full and severe examination of the reports, statistics, and other evidence concerning this and other outbreaks in which preventive inoculations were made, the Report (1901) of the Indian Plague Commission must be studied. The Commissioners, Professor T. R. Fraser, Mr. J. P. Hewett, Professor (now Sir) A. E. Wright, Mr. A. Cumine, Dr. Ruffer, and Mr. C. J. Hallifax, Secretary, travelled and took evidence in India from November 1898 to March 1899: during which time they held 70 sittings and examined 260 witnesses, some at great length. The evidence and the report are published in five large volumes. The report, 540 pages in all, deals exhaustively with the whole subject. It represents the very least--what might almost be called the very worst--that can be said of Haffkine's fluid: and, of course, it reads rather differently from the reports of the men who, with their lives in their hands, and worked almost past endurance, fought plague themselves. The following paragraphs give, so far as possible, the bare facts of various outbreaks of the disease in 1897-99, in which Haffkine's fluid was used. 1. _Daman_ Plague broke out in Daman, a town in Portuguese territory, north of Bombay, and in constant communication with Bombay by sea, in March 1897. By the end of the month, when a Government cordon was placed round the town, about 2000 out of 10,900 had fled. The outbreak reached its height in mid-April, and was practically over by the end of May. Inoculations were begun on 26th March. The total population on that day (2000 having gone out, and 670 having died of plague) is estimated at 8230. Of these, 2197 were inoculated, and 6033 were left uninoculated. Among the inoculated there were 36 deaths = 1.6 per cent.; among the uninoculated 1482 deaths = 24.6 per cent. The Commissioners criticise these figures severely, and do not accept them as exact. But they admit the evidence as to the results of inoculation among the Parsee community of Daman. Of this community, 306 in number, 277 were inoculated, and only 29 were left uninoculated. Among the inoculated there was 1 death = 0.36 per cent.: among the uninoculated there were 4 deaths = 13.8 per cent. They admit, also, the house-to-house investigations made by Major Lyons, I.M.S., President of the Bombay Government Plague Committee. At the end of May, he visited 89 houses, in 62 of which both inoculated and uninoculated were living together. He found that out of 382 inoculated, 36 had died = 9.4 per cent.; out of 123 uninoculated, 38 had died = 30.9 per cent. 2. _Lanauli_ Plague attacked Lanauli, a small hill-station and railway depot, during April to September 1897. The entire population was estimated at about 2000. Inoculations were begun on 24th July in two wards of the town, and a daily house-to-house inspection was instituted. The figures reported, on the basis of the average daily strength of the two groups, are as follows:-- Inoculated, 323, with 14 cases, of which 7 died = 2 per cent. Uninoculated, 377, with 78 cases, of which 57 died = 15 per cent. The Commissioners criticise the method on which these figures are based, and do not accept them as accurate. But they agree that inoculation "exerted a distinct preventive effect"; and they admit Major Baker's evidence--"In the place where inoculation had been made use of, the town was thriving and full of people; and the other part of the town was absolutely empty. One side had plague, and the other had none." 3. _Kirki_ The figures here were obtained under especially favourable circumstances; and the Commissioners have, practically, no fault to find with their accuracy. The following account is by Surgeon-Major Bannerman, Superintendent of the Plague Research Laboratory, Bombay:-- "Plague broke out in Kirki, in the artillery cantonment, situated four miles from Poona; and the followers of the four batteries stationed there suffered severely. These men were living with their families in lines on a sloping plain, under military discipline, and in circumstances far superior in a sanitary sense to those of the average villager. When the disease appeared, the lines were isolated, so that none could enter or leave without the knowledge of the military. A special hospital was erected close by, where all sick persons were sent as they were discovered by the search parties of European artillerymen, who visited each house thrice daily. It is therefore probable that all cases of plague were promptly discovered and removed to hospital: and in each case the usual disinfection was thoroughly and systematically carried out. Yet, in spite of all this, it was found that, in those not protected by inoculation, 1 out of every 6 of the population was attacked, and 2 out of every 3 attacked died. The epidemic was, therefore, a severe one. The population of the lines numbered 1530; and, out of these, 671 volunteered for inoculation. At the close of the epidemic, the plague-hospital admission and discharge book was examined, and compared with the register of those inoculated, when the following result was got. The population operated on being under military discipline, and confined to their lines, makes the accuracy of the figures undoubted:-- Inoculated, 671, with 32 cases, of which 17 died = 2.5 per cent. Uninoculated, 859, with 143 cases, of which 98 died = 11.4 per cent. "Here, then, is seen a body of people divided into two groups by the fact that one had undergone inoculation and the other not, _but differing in no other way_, reacting towards plague in such a markedly different manner that the conclusion is forced on one, that the inoculation must be the cause. Seeing the absolute similarity of conditions, _the 671 inoculated should have had proportionately 112 cases and 77 deaths, if they had remained as susceptible to the disease as their uninoculated brothers, sisters, parents, wives, husbands, children; but, instead of that, they had only 32 cases and 17 deaths_. This death-rate would doubtless have been still further reduced, but for the fact that a very much weakened vaccine had to be used, owing to the demand having got beyond the resources of the laboratory at that time." 4. _Belgaum_ In Belgaum, a town of Southern India with a normal population of about 30,700, two outbreaks of plague occurred in quick succession. The first outbreak lasted from November 1897 to May 1898; the second, from July 1898 to January 1899. During the two epidemics, 2466 persons were inoculated. Of these, it was reported that only 61 (or 62) had been attacked, of whom 33 died = 1.34 per cent. But these figures, in the judgment of the Commission, cannot be accepted as even approximately correct. There are, however, two groups of these Belgaum cases, one of which the Commission admits as substantially accurate, and the other as absolutely accurate. These groups are, (1) the Army cases; (2) the cases reported by Major Forman, R.A.M.C., Senior Medical Officer of the Station. (1) _The Army Cases._-These cases occurred in the 26th Madras Infantry, which was living in lines close to the cantonment and the city. The first case of plague in the regiment was on 12th November 1897. Ten days later, the regiment was moved out into camp. Inoculation was begun, by Surgeon-Major Bannerman, on 23rd December, up to which time there had been, among the regiment and its families and followers, 78 cases, with 49 deaths. The following account of the inoculations is given by Surgeon-Major Bannerman:-- "No difficulty was experienced in persuading the men to consent to inoculation, when it was explained to them that they would be free to return to their houses in the lines after being operated on. General Rolland was the first to be operated on, and his example, combined with that of the officer commanding, and their medical officer, who were all operated on in front of the men, sufficed to convince the Sepoys of the harmlessness of the operation: and the only difficulty that then remained was to perform the operation fast enough.... The community was, practically, completely inoculated by the end of the year. The total operated on was 1665, out of a population of 1746 living in the lines at that date. The 81 not operated on were infants, women far advanced in pregnancy, and the sick in hospital chiefly, though one solitary Sepoy has, up to the present time, refused to submit to operation." From this time onward to the end of the first epidemic, though the disease was at its height in January in the neighbouring city and cantonment, and though the men were allowed to go freely to these places after inoculation, _only 2 out of the 1665 were attacked, and both recovered_. When the second epidemic came, in July 1898, the troops, families, and followers, were reinoculated at their own request, 1801 in all. "Practically no one was left in the lines unprotected by inoculation." From this time onward to the end of the second epidemic, though it was much more severe than the first, only 12 cases occurred. _In the first epidemic, before inoculation, 78 cases occurred, and 2 after it: in the second, and much more severe, epidemic, though the sanitary measures adopted in both epidemics were similar, only 12 cases occurred._ "It would hardly appear to be open to doubt," says the Commission, "that the practical immunity of the regiment, during the second outbreak, was due to inoculation." (2) Major Forman's evidence before the Commission is very striking, though the figures are small. The following abstract of it is given in the Report of the Commission:-- "The groups of persons, concerning whom Major Forman gave us evidence, were his private servants, and the hospital attendants of the Belgaum Station Hospital with their wives and children. He inoculated these groups when plague first broke out in the town, and was able to keep in touch with them continuously after that time. Regarding the first group, he says, bringing down their history to 3rd March 1899, 'Of my private servants there were in all, including their wives and children, 28 people inoculated. There have been no cases of plague, and no deaths up to date. There were 3 uninoculated. One was a child of 9 years of age, whose father refused to allow it to be inoculated. It died of plague 12 days after the other people were inoculated. The other 2 cases that were not inoculated were not so distinctly under my own observation. One was a sweeper employed in the cantonment, and sleeping in my compound: he, I am told, died of plague some months afterwards. The other was my water-carrier: he threw himself into a well: I was informed that he had buboes and fever, and ran away to escape segregation. Of the 28 inoculated, none died of plague: and of 3 uninoculated, 2 are said to have died of plague, and 1 undoubtedly died of plague.'" "Regarding the second group of which he gave us particulars, Major Forman said that, out of 90 hospital servants, 87 were inoculated. Of the inoculated persons, 1 died from fever and endocarditis, and 1 died of plague. Excepting these two, the rest of the inoculated were alive and well in March 1899. Only 3 persons remained uninoculated. Of these, one was not operated upon, because she had recently been delivered; another was not operated upon, because she was pregnant; and the third was a boy of 16 years of age, whose father refused to let him be inoculated. The boy died of plague, two months after the inoculation of the rest of the hospital servants had been done. One of the two uninoculated women died of plague two days after the boy, she having been in attendance upon him. The other uninoculated woman remained well." 5. _The Umarkhadi Jail, Bombay_ Plague broke out in this jail on the last day of 1897, and 3 prisoners died. Next day, 1st January 1898, all the prisoners were paraded, and all were willing to be inoculated. But it was decided to divide them into two equal groups, and inoculate one group. There were 402 altogether: 2, when their turn came, refused to be inoculated: thus 199 were inoculated, and 203 were left uninoculated. No distinction was made between the two groups: "They had the same food and drink, the same hours of work and rest, and the same accommodation." The plague did not come wholly to an end till March. The figures, since the inmates of a jail are a shifting population, are based on the average daily number of each group: this was 147 for the inoculated, and 127 for the uninoculated. The figures are:-- +-----------------------+--------+---------+ | Average Daily Number. | Cases. | Deaths. | +-----------------------+--------+---------+ | Inoculated 147 | 3 | 0 | | Uninoculated 127 | 9 | 5 | +-----------------------+--------+---------+ The Commission draw attention to "the important fact that, during the whole period of the outbreak, the number of attacks among the inoculated was only one-third of the number among the uninoculated; and that the disease among the inoculated was remarkably mild, resembling mumps more than plague, though the cases among the uninoculated were of average severity." According to Surgeon-Major Bannerman, the hospital authorities were doubtful whether these three cases among the inoculated were plague at all. 6. _Undhera_ The figures for Undhera are very valuable: "The conditions," says Surgeon-Major Bannerman, "approached very nearly the strictness of a laboratory experiment." Even the Commissioners are enthusiastic here. Undhera is an agricultural village, 6 miles from Baroda. Plague broke out in it, in January 1898. A careful census was taken, and showed a population of 1029. By 12th February there had been 76 deaths. On that day the village was visited by Mr. Haffkine, Surgeon-Major Bannerman, and other experts, and 513 persons were inoculated:--_By reference to the census papers, the whole of the inhabitants were called out, house by house, and the half of each household inoculated. In this way, an endeavour was made to inoculate half the men, half the women, and half the children in each family, and to arrange that a fairly equal proportion of the sickly-looking should be placed in each division._ The plague lasted 42 days after the inoculations, and affected 28 families. On 4th April a house-to-house investigation was made by Mr. Haffkine, Surgeon-General Harvey, Surgeon-Major Bannerman, and Captain Dyson. The figures are as follows:-- +---------------+-------------------+------+-------+-------------+ |Population on | |Cases.|Deaths.| Mortality. | |12th February. | | | | | +---------------+-------------------+--------------+-------------+ |1029 - 76 = 953| Inoculated, 513 | 8 | 3 |0.6 per cent.| | | Uninoculated, 440 | 28 | 27 |6.0 per cent.| +---------------+-------------------+------+-------+-------------+ Thus, out of 28 families, where the protected and the unprotected lived and ate and slept together, the protected, 71, had 3 deaths; and the unprotected, 64, had 27. The percentage of attacks was four times higher among the unprotected; the percentage of deaths was ten times higher. 7. _Khoja Community, Bombay_ The head of this community, H.H. Sir Sultan Shah, Aga Khan, K.C.I.E., opened a private station for the inoculation of the community in March 1897, and again in December of that year. He was himself inoculated three times, and many of the community so often as five times. The work of inoculation went on daily, and by 20th April 1898 the number of persons inoculated or reinoculated was 5184. The whole community, according to a careful census taken at the beginning of 1898, numbered 9350; but, since many families had fled to avoid the infection, this number is too low. The Commissioners guess 9770: Haffkine, to the disadvantage of his own statistics, guesses so high as 13,330. The number of the inoculated or reinoculated shifted, of course, as the work went on: their average daily number during the four months of plague, January to April 1898, was 3814. During these four months, the number of deaths _from all causes_ in the whole community was 184. According to the average mortality of the community in times of no plague, the deaths _from all causes_ during four months would be 102. It may fairly be assumed that the extra deaths, 82, were due to plague: and, indeed, 64 plague-deaths were either acknowledged by the relatives, or certified by the burial-books of the community. _Of these 82 deaths, 3 occurred among the inoculated or reinoculated, and 77 among the uninoculated._ The Commissioners find fault with these figures: "Nevertheless, quite apart from the statistics put before us, which we think inaccurate, we do not doubt that inoculations had a good effect, especially as much weight must be allowed to the opinion of a community so intelligent as that of the Khojas." 8. _Hubli_ This, the greatest and most amazing of all instances of preventive plague-work, was done in a town of 50,000 persons. The following report, by Surgeon-Captain Leumann, was forwarded to the Plague Commissioners by Mr. E. K. Cappel, Collector of Dhárwár, with this comment:-- "The town of Hubli--a mercantile town of over 50,000 inhabitants--was attacked by plague in an epidemic form at the commencement of the monsoon rains. The average rainfall between April and October amounts to more than 28 inches. Under these circumstances, although a large and weather-proof health camp had been prepared for emergencies, complete evacuation of the infected townsite was impossible; and the attempt to effect it would have led to the severest hardships and to the immediate spread of the disease into surrounding villages and districts. It was for this reason that the determination was formed to make a bold and comprehensive experiment with the prophylactic, and not on any _à priori_ grounds. If this experiment had failed, the results, judged by the actual mortality among the uninoculated, would have been appalling. _All possible sanitary measures in the shape of disinfection, unroofing of houses, and segregation, were applied concurrently with inoculation, as Government are already aware; but the rate of mortality among those who held back from inoculation rose at one time to a height which, I believe, has never been approached elsewhere...._ "However, the experiment, in the hands of Dr. Leumann, did not fail, and it has afforded a demonstration of success which is of Imperial importance. Many thousands of lives have undoubtedly been saved, and at the present moment the plague mortality is merely sporadic, and Hubli is steadily regaining its normal population and trade, though surrounded by infected villages." The Hubli report must be put at full length, for the vivid picture it gives of plague in India, and of the difficulties besetting the magnificent work of the Indian Medical Service. It is a story that Mr. Kipling ought to write. And it is to be noted that Surgeon-Captain Leumann, who saved Hubli, recognised the extreme importance of other methods than inoculation--disinfection, isolation of cases, evacuation of infected districts. He says:-- "While paying the highest tribute to the value of Mr. Haffkine's inoculation method, which I claim, here in Hubli, to have put to perhaps the severest test to which it has yet been subjected, I am of the opinion that individual protection is, on however great a scale conducted, of less importance to that of general protection and hygiene (considering each method separately, that is to say), for it seems to me more radical, if not more rational, to eradicate a disease than to leave it to pursue its course and only protect people against its ravages." Sanitation, therefore, was Dr. Leumann's faith. Now for his works:-- "I first started inoculation here on 11th May.... When I began my inoculations, I operated first of all on some European or native gentlemen in front of a crowd of poor and low-caste people, whom I had gathered together in the worst-affected area, and they were thus soon induced to ask for inoculation themselves.... They have presented themselves, by the hundred, at all times of the day, before myself and others, for the purpose of being inoculated.[34] ... I have never experienced the slightest difficulty in inoculating Mussulmanis or any other purdáh women in Hubli.... The very men who, in March last, created a disturbance in Hubli, were not only the first and the most willing to undergo inoculation, but also to bring their wives and families to my hospital, or to invite me to their homes to inoculate them. [34] Compare the account of the inoculations at Gaday, in the _Lancet_, 11th February 1898: "To see the crowd waiting and struggling to pass the barrier is a strange sight; old men and women, young children, and mothers with babes in their arms, form a daily crowd numbered by hundreds, who wait for hours to get their chance of the day's inoculation." "Inoculated persons holding certificates of double inoculation have, at my special wish and order, been left in their homes throughout this epidemic; only their clothes, house, and property being disinfected on the occurrence of a plague case or death in their house. As the vast majority of plague cases have never been notified before death in Hubli (nor, in my experience of nearly two years, elsewhere, if native supervision be largely resorted to), it will readily be understood that the majority of the inoculated have actually been living in the same house, or even room, with a plague case (often of the pneumonic type, whose terrible power of spreading the disease was first shown by Professor Childe, I.M.S., of Bombay) during the whole of the time that case was living, probably attending on the patient, breathing the same stuffy air, and, perhaps, sharing the same blanket; and I attach at the end of this report a long series of cases where such conditions have occurred, _the non-inoculated dying of plague, and the inoculated escaping, almost to a man_. "Various critics on my work, not knowing what the actual facts were and are, have at different times asserted that the inoculated inhabitants of Hubli left the town in larger numbers than the non-inoculated. Exactly the reverse was the case. The British officers on plague duty here, and all the Divisional Superintendents, invariably replied (officially and in writing when so required) that the non-inoculated left Hubli in far greater numbers and proportion than the inoculated; and my own observations entirely bear out this statement. "It has been urged that those who received inoculation were of a class or classes better protected than others against plague by reason of their habits, the food they eat, the houses they live in, etc. In reply, I unhesitatingly state that if there be but one town in India where that line of argument will not hold good, it certainly is Hubli; for _not only were the poorer, dirtier, lower-caste people the first to be persuaded to receive inoculation, but I made it my personal and special duty to work amongst them_. My first few thousand inoculations were almost entirely amongst the lowest and poorest of the people. The Brahmins are, perhaps, of all castes, supposed to be the most cleanly in their houses, habits, etc., yet the Brahmins of Hubli (who at first, imagining themselves immune, were the foremost and greatest perverters of the truth concerning its efficacy, and the last to apply for the protection inoculation affords), simply inundated the various inoculation centres, as soon as plague began to spread in their midst, clamouring for the very method of which they had only lately tried to prevent others from availing themselves. "Unfortunately, the average native, educated or not, appears to have the very greatest aversion to notifying any case of sickness--plague or other--and hence, in my opinion, it becomes more necessary than ever to protect the people by inoculation, since they will not help to protect themselves by the foremost and simplest of sanitary and hygienic measures.[35] With so few police (and those none too good) to help one; an inadequate British Staff; with so much reliance placed in Native Superintendents and Supervisors, and a Municipality so bankrupt that it could not apparently afford to buy enough blankets out of its own funds for the patients in the Plague Hospitals--the work of segregation, house-to-house inspection, etc., became, from a medical point of view, absurdly insufficient. "The total number of inoculations performed in Hubli, both on actual inhabitants and on people from outside (villages) between 11th May and 27th September, amounts to some 78,000 altogether." [35] Compare the account given by the Rev. H. Haigh (_Methodist Recorder_, December 1898), of the plague at Bangalore: "The native population do all they can to elude the vigilance of the authorities. In order to escape segregation, the householders in many instances refrain from reporting plague, and not infrequently bury the corpse secretly. Not only is any spare piece of ground used as a burial-place, but the body is at times thrown into a well or tank, or dropped over the wall of some European compound. During one week three plague corpses were found, badly decomposed, in reservoirs commonly resorted to for drinking purposes." I +------------+---------+-----------+-----------+-------------------+ | | | | | Plague-deaths | | | | | | among: | | Dates. |Census of| Non- |Inoculated.+-----------+-------+ | | Hubli. |Inoculated.| | Non- |Inocul-| | | | | |Inoculated.| ated. | +------------+---------+-----------+-----------+-----------+-------+ |Five weeks |Fell from| | | | | | from May 11|50,000 to| | | | | | to June 14 | 47,427 | 44,573 | 2,854 | 47 | 1 | | | | | | | | |Week ending:| | | | | | | June 21 | 47,082 | 41,494 | 5,588 | 22 | 3 | | June 28 | 47,485 | 39,042 | 8,443 | 29 | 1 | | July 5 | 46,537 | 36,020 | 10,517 | 55 | 6 | | July 12 | 46,518 | 33,255 | 13,263 | 34 | 6 | | July 19 | 45,240 | 29,716 | 15,524 | 82 | 7 | | July 26 | 43,809 | 24,112 | 19,697 | 100 | 15 | | Aug. 2 | 43,707 | 21,031 | 22,676 | 140 | 16 | | Aug. 9 | 42,768 | 15,584 | 27,184 | 272 | 19 | | Aug. 16 | 40,441 | 10,685 | 29,756 | 386 | 61 | | Aug. 23 | 39,400 | 6,367 | 33,033 | 371 | 41 | | Aug. 30 | 38,210 | 4,094 | 34,116 | 328 | 28 | | Sept. 6 | 38,382 | 2,731 | 35,469 | 227 | 34 | | Sept. 13 | 38,408 | 1,116 | 37,292 | 138 | 47 | | Sept. 20 | 39,142 | 937 | 38,205 | 106 | 55 | | Sept. 27 | 39,315 | 603 | 38,712 | 58 | 20 | +------------+---------+-----------+-----------+-----------+-------+ II +---------------+-------------------------+----------------------+ | | Plague death-rate. | | | | Comparison per 1000 | Percentage reduction | | Dates. | between | of Plague death-rate | | +------------+------------+ in favour of the | | | Non- | Inoculated.| Inoculated. | | | Inoculated.| | | +---------------+------------+------------+----------------------+ | Five weeks | | | | | from May 11 | | | | | to June 14 | 1.022 | .350 | Over 65 per cent. | | | | | | | Week ending: | | | | | June 21 | .530 | .527 | About 1 per cent. | | June 28 | .742 | .118 | Nearly 85 per cent. | | July 5 | 1.524 | .570 | About 63 per cent. | | July 12 | 1.022 | .452 | Nearly 56 per cent. | | July 19 | 2.793 | .450 | 84 per cent. | | July 26 | 4.147 | .761 | 82 per cent. | | Aug. 2 | 6.656 | .705 | 89 per cent. | | Aug. 9 | 17.325 | .698 | Over 96 per cent. | | Aug. 16 | 33.694 | 2.083 | 94 per cent. | | Aug. 23 | 57.011 | 1.241 | 98 per cent. | | Aug. 30 | 80.116 | .820 | 98 per cent. | | Sept. 6 | 83.112 | .958 | 99 per cent. | | Sept. 13 | 112.903 | 1.260 | Over 99 per cent. | | Sept. 20 | 113.127 | 1.439 | Over 99 per cent. | | Sept. 27 | 96.185 | .517 | Over 99 per cent. | +---------------+------------+------------+----------------------+ "It appears that if the 47,427 inhabitants had remained, as they did--in their town, without running away by rail or otherwise, or without camping out in a mass--and if no inoculation had been resorted to--they would have lost 24,899 souls, or a little over half of their number. The official records show that this has actually occurred, during the present terrible outbreak, in a number of large villages, of 2000 inhabitants and over, in the Hubli _taluka_ and elsewhere in the Dhárwár District, where no inoculation was done, and no camping-out was possible on account of the wet weather." (Haffkine's commentary on Dr. Leumann's report.) That is the story of Hubli; and, as it stands, it is almost incredible. The Commissioners, by very strict inquiry, reduced it to credibility without robbing it of glory. The inquiry brought out more instances of the immeasurable difficulty of the work. Natives who wished to avoid inoculation would escape through the back door at the sight of a plague officer: bribery, personation, sale or transfer of certificates of inoculation, concealment of cases and of deaths, were all practised by those who wished not to be inoculated, or to get the privileges of the inoculated without inoculation, or to save their infected houses from being disinfected and unroofed. Again, with the people dying like flies, and many of them bearing no mark of identification, and with the medical officers overworked past human endurance, the wonder is, not that the statistics were faulty, but that there are any statistics at all. Certainly, the Commission is well within the mark in saying, "It is quite clear that a very large number of lives must have been saved in Hubli by inoculations during the whole course of the epidemic there. _Moreover, we may note that an arithmetical estimate is not the only criterion by which we can appreciate the value of inoculations. And in Hubli their value is approved by the consensus of opinions of officers who have seen probably far more of this process and its results in practice than any other persons in India, and who, having every facility for forming a sound judgment as to its effect where plague was really virulent, are satisfied as to its great value._" Finally, as at Daman so at Hubli, there are lesser groups of statistics, of that kind which is _approved by the consensus of opinions of officers_. These are, (1) Lieutenant Keelan's house-to-house investigation; (2) the Southern Mahratta Spinning Mills; (3) the Southern Mahratta Railway employés. 1. Lieutenant Keelan made a house-to-house visitation of 200 houses, in each of which there were protected and unprotected persons living together, and in each of which there had been one or more cases of plague. The figures for 69 of these houses are appended to Captain Leumann's report. They are as follows:-- +----------------+----------+--------+---------+------------+ | | Inmates. | Cases. | Deaths. | Mortality. | +----------------+----------+--------+---------+------------+ | Inoculated | 336 | 11 | 4 | 1.19 | | Uninoculated | 144 | 84 | 80 | 55 | +----------------+----------+--------+---------+------------+ These 69 houses were selected: there was nothing unfair in the method of selection, still, they were "good houses"; they are not, therefore, exact for statistics; but, as the Commissioners say, they are "of interest as quite special examples of successful inoculation." 2. In the Southern Mahratta Spinning and Weaving Company's Mills, a careful record of inoculation was kept and checked by the manager. The number of the workpeople at the time when inoculation was begun, 21st June, was 1173. At the end of the epidemic the figures were:-- +--------------------------+---------+---------------+ | | Deaths. | Mortality per | | | | cent. | +--------------------------+---------+---------------+ | Inoculated twice 1040 | 22 | 2.11 | | Inoculated once 58 | 8 | 13.79 | | Uninoculated 75 | 20 | 26.66 | +--------------------------+---------+---------------+ Here, again, the figures have not a statistical value: "We are not informed whether the inoculations were performed simultaneously; or at what stage of the outbreak the average strength of the inoculated was reached." All the same, what Major Bannerman says of them is true--_The experience in this company's mill at_ _Hubli should be an object lesson to all mill-owners in plague-stricken towns._ 3. The figures for the Southern Mahratta Railway are given by Major Bannerman in his "Statistics" (1900): they are not mentioned in the Report of the Plague Commission. They are of great value, because the daily shifting of the numbers was recorded as the work of inoculation went on, and the date of each case of plague was also noted. Major Bannerman gives the following account:-- "The railway employés were living in barracks, and in the railway yard, apart from the general population of Hubli town. _They were under close daily inspection by English officials_, who formed a committee for this purpose, with Dr. Chenai as their medical adviser. The results may therefore be regarded as accurate in a high degree, the numbers dealt with not being excessive, and the supervision strict." The figures, based on the average numbers in each group, are as follows:-- +------------------------+--------+---------+---------------+ | | Cases. | Deaths. | Mortality per | | | | | cent. | +------------------------+--------+---------+---------------+ | Twice inoculated 990 | 6 | 1 | 0.1 | | Once inoculated 270 | 5 | 1 | 0.3 | | Uninoculated 760 | 35 | 21 | 2.7 | +------------------------+--------+---------+---------------+ These eight instances must suffice: many must be left out--among them, Dhárwár and Gadag, where Miss Corthorn, M.B., did work as splendid as Leumann's work at Hubli; and Mr. Anderson's work in the Ahmednagar villages; and many more. These plague-reports are to be read, not for their record of heroic zeal and resourcefulness, but only as one more example of many thousand lives saved by a method learned from experiments on animals. But, of course, there is not, and perhaps there never will be, a national acceptance and adoption of this method through the length and breadth of India. It does not work miracles; it is an uncomfortable process to submit to; privileges must be offered with it, or the native will often prefer to take his chance; the protection is of uncertain duration; all sorts of lies are told about it, partly by anti-vivisectionist writers, partly by native political agitators, partly by the _hakims_. For instance, at a meeting of _hakims_ at Masti, Lahore, on 11th April 1898, the following resolutions were passed:-- "That in the opinion of this meeting the bubonic plague is not a contagious disease. It originates from poisoned air, and this poison is created in the air on account of atmospherical germs and the excess of terrestrial humidities. "That this meeting, having carefully considered the Resolution of the Punjab Government (11th January 1898), is of opinion that the rules embodied in that Resolution (isolation, disinfection, etc.), are unnecessary under the principles of Unani medical science." And among statements to be made to the Plague Commissioners was the following, from a native practitioner in Bombay (April 1899):-- "I do not think the plague was imported in Bombay from Hong Kong or anywhere else. I attribute three sources of causes of outbreaks of plague in Bombay: (_a_) The predisposing cause was the Bombay Municipality; (_b_) The exciting cause was the Nature herself; (_c_) The aggravating cause was the Plague Committee." All these difficulties were well stated by Surgeon-General Harvey, Director-General of the Indian Medical Service, at the discussion on Haffkine's discourse before the Royal Society, June 1899:-- "The people of England should consider the difficulties attending the work of a bacteriologist in India.... He had no doubt as to the value of the inoculations. At Undhera he carefully examined the results of the experiment, and, as far as he could judge, there was no possibility of error. The results in that experiment were such as to be 90 per cent. in favour of the inoculated against the uninoculated. The natives of India were, however, a strange people, and it was difficult to prophesy how they would act. In Calcutta, the mention of inoculations had driven in hot haste from the city 300,000 people, many of whom afterwards returned and were inoculated; while at Hubli he had seen the inhabitants come in their thousands to be inoculated and pay for the inoculations. The medical officer in charge at Hubli had performed about 80,000 inoculations, and had only observed some 12 abscesses. He thought that 12 abscesses only, in 80,000 inoculations, showed good results. But, after all, what were the numbers of inoculations performed to the 300,000,000 inhabitants of India? He felt that even if every one consented to be inoculated it was impossible to provide the vaccine or the medical officers for such a demand. It was accordingly to sanitary improvements that he looked with the most confidence to protect India against the plague." Therefore, now and for many years to come, preventive inoculation must fall into line with the other world-wide ways of fighting plague--quarantine, notification, isolation, all sanitary measures, destruction of rats--_le rat, le génie de la peste_--evacuation of infected towns, disinfection or unroofing of infected houses. Happily, this is just what it does. That admirable paper, the _Indian Medical Gazette_ (September 1901), has put this fact very simply: "No one ever imagined that inoculation was the _only_ means of fighting plague. Its great value consists in its immediate application. To sanitate, ventilate, and practically rebuild a town or village takes time; and in the meantime thousands die." For sudden outbursts of plague--since rats are one chief source of infection, and notification is fundamentally abhorrent to native custom, and evacuation may ruin trade, or spread infection, or be impossible by reason of the rains--since "East is East, and West is West"--it is not always possible to provide, for an Indian village smitten by plague, the excellent arrangements of the Western world. In all such cases, and in all cases of epidemic plague within narrow limits, as in jails, barracks, mills, and the like centres of human life; and in all inner communities, such as the Parsee community at Daman, or the Jewish community at Aden--by every test of this kind, the saving power of preventive inoculation has been proved, again and again, past all doubt. As for those larger death-traps, Hubli, Dhárwár, and the rest of them, here, though the statistics are inexact, we have the word of the men and women themselves who stood between the dead and the living, and the plague was stayed. Such faults as there were, in 1899, in the treatment--the contamination of this or that stock of the fluid, and the inadequate method of standardisation--have been duly noted by the Commission. The rush for the fluid in 1899 may be estimated from the following paragraphs:-- (i.) _Paris._ "The preparation of anti-plague serum is being rapidly proceeded with; up to the present time the Institute has supplied it, in response to all the very numerous requests which have come from Portugal, Spain, Italy, and Turkey, without encroaching on the reserve kept in readiness for Paris and the departments." (_Lancet_, 16th September 1899.) (ii.) _India._ "The spread of plague westward to Spain and Portugal seems to have excited more or less general alarm, and I hear that an unprecedented demand has suddenly arisen for the plague prophylactic fluid. The Government of India have been asked the cost of supplying from 50,000 to 100,000 doses, and the earliest date at which this quantity could be despatched. It is also desired to know if in case of need 50,000 doses a week could be sent to London. Russia desires to obtain a considerable stock for Port Arthur. Italy has been making inquiries for home use; and also Portugal, in order to inoculate at Mozambique. The present laboratory is at Government House, Parel, Bombay, and has only recently been fitted up by the Government of India. About 10,000 doses a day can be turned out, but it is thought that still further enlargements will be required if the demand should increase beyond this amount." (_Lancet_, 23rd September 1899.) * * * * * It would take too long for the present purpose to consider what has been done, not only for the prevention of plague, but also for its cure by a serum treatment. The results obtained by this treatment in India have not been very good; but Yersin and others report better results in other countries. Good results are reported from Amoy (1896), Nhatrang (1898), Oporto (1899), and Buenos Ayres (1899-1900). In Glasgow, the prophylactic use of Yersin's serum seems to have done excellent service: the success of its curative use was not very striking. The curative results at Nhatrang (Yersin, _Annales de l'Institut Pasteur_, March 1899) are notable. Nhatrang is an Annamese fishing-village; and the plague, when it was left to itself, killed every case that it got:-- "La peste s'est montrée excessivement meurtrière chez les Annamites. Sur 72 cas de peste, 39 personnes chez lesquelles la maladie a évolué normalement, ou qui n'ont été traités que par des médecins indigènes, sont mortes sans exception. Les 33 autres cas ont pu être traités par le sérum, quelquefois dans de bonnes conditions, mais le plus souvent quelques heures seulement avant la mort. Malgré cela, nous avons obtenu 19 guérisons et 14 décès, ce qui fait une mortalité de 42 per cent., chez les traités. _Ainsi, d'une part, 100 pour 100 de mortalité chez les non-traités; de l'autre, 42 per cent. chez les malades qui ont reçu du sérum._ Ces chiffres confirment les résultats que j'avais obtenu en Chine en 1896." A long review of this curative treatment, fairly hopeful but nothing more, is given in the Report of the Plague Commission, vol. v., pp. 269-320. The Commissioners are of opinion that it ought not yet to be extended, as a general measure, over all the districts affected with plague; and that there is need of more work in bacteriology before it can be thus extended. "We desire to record our opinion that, though the method of serum-therapy, as applied to plague, has not been crowned with a therapeutic success in any way comparable to that obtained by the application of the serum method to the treatment of diphtheria, _none the less the method of serum-therapy is in plague, as in other infectious diseases, the only method which holds forth a prospect of ultimate success._" It is a strange contrast, between this opinion and the statements made by the opponents of all experiments on animals. Some of these statements will be found in Part IV. of this book. Happily for the world, no amount of foul language can hinder the good work; and, when we talk of _Empire-building_, and of _deeds that win the Empire_, we must reckon bacteriology among them: as Lord Curzon did, in his speech at Calcutta, March 3, 1899--_What is this medical science we bring to you? It is built on the bed-rock of pure irrefutable science; it is a boon which is offered to all, rich and poor, Hindu and Mohammedan, woman and man._ IX TYPHOID FEVER. MALTA FEVER TYPHOID FEVER The names of Klebs, Eberth, and Koch, are associated with the discovery, in 1880-81, of the bacillus of enteric fever, _bacillus typhosus_; and it was obtained in pure culture by Gaffky in 1884. It has been studied from every point of view, in man and in animals; in the blood, tissues, and excretions; in earth, air, water, milk, and food; in its distribution, methods of growth, and chemical products. Especially, the study of its chemical products has been directed toward (1) immunisation against the disease, (2) bacteriological diagnosis of the disease at an early stage. The date of the first protective inoculations against typhoid is July to August 1896: they were made at Netley Hospital, by Professor Wright and Surgeon-Major Semple. The first inoculations in Germany, made by Pfeiffer and Kolle, were published two months later. The story of these famous Netley inoculations is told in the _British Medical Journal_, 30th January 1897. Eighteen men offered themselves-- "A good deal of fever was developed in all cases, and sleep was a good deal disturbed. These constitutional symptoms had to a great extent passed away by the morning, and laboratory work went on without interruption.... With two exceptions, all these vaccinations were performed upon Medical Officers of the Army or Indian Medical Services, or upon Surgeons on Probation who were preparing to enter those services." Good luck attend all eighteen of them, and immunity against typhoid, wherever they are. The doses that they received were estimated in proportion to the dose that would kill a guinea-pig of 350-400 grammes weight; and the protective fluid contained no living bacilli:-- "The advantages which are associated with the use of such 'dead vaccines' are, first, that there is absolutely no risk of producing actual typhoid fever by our inoculations; secondly, that the vaccines may be handled and distributed through the post without incurring any risk of disseminating the germs of the disease; thirdly, that dead vaccines are probably less subject to undergo alterations in their strength than living vaccines." The first use of the vaccine during an outbreak of typhoid was in October 1897, at the Kent County Lunatic Asylum. The treatment was offered to any of the working staff who desired it:-- "All the medical staff, and a number of attendants, accepted the offer. _Not one of those vaccinated--84 in number--contracted typhoid fever: while of those unvaccinated and living under similar conditions, 16 were attacked._ This is a significant fact, though it should in fairness be stated that the water was boiled after a certain date, and other precautions were taken, so that the vaccination cannot be said to be altogether responsible for the immunity. Still, the figures are striking." (_Lancet_, 19th March 1898; see also Dr. Tew's paper, in _Public Health_, April 1898.) Certainly, they are striking; so is the story of the eight young subalterns on the Khartoum expedition, of whom six were vaccinated, and two took their chance. The six escaped typhoid, the two were attacked by it, and one died. But these figures are too small to be of much value. The first anti-typhoid inoculations on a large scale were made among British troops in India (Bangalore, Rawal Pindi, Lucknow), when the Plague Commission, of which Professor Wright was a member, was in India, November 1898 to March 1899. These inoculations were voluntary, at private cost, and without official sanction; though the original proposal for them, in 1897, had come from the Indian Government. Pending official sanction, they were stopped. Then, on 25th May 1899, the Indian Government made application to the Secretary of State for India that they should be sanctioned, and should be made at the public cost. The application is as follows:-- "The annual admissions _per mille_ for enteric fever amongst British troops in India have risen from 18.5 in 1890 to 32.4 in 1897, while the death-rate has increased from 4.01 to 9.01; and we are of opinion that every practicable means should be tried to guard against the ravages made by this disease. The anti-typhoid inoculations have been, we believe, on a sufficiently large scale to show the actual value of the treatment, while the results appear to afford satisfactory proof that the inoculations, when properly carried out, afford an immunity equal to or greater than that obtained by a person who has undergone an attack of the disease; further, the operation is one which does not cause any risk to health. In these circumstances, we are very strongly of opinion that a more extended trial should be made of the treatment; and we trust that your Lordship will permit us to approve the inoculation, at the public expense, of all British officers and soldiers who may voluntarily submit themselves to the operation." On 1st August, the Secretary of State for India announced in Parliament that this treatment, at the public expense, had been sanctioned. On 20th January 1900, Professor Wright published in the _British Medical Journal_ an account of these 1898-99 inoculations in India. "They were undertaken under conditions which were very far from ideal. In particular, there is reason to suppose that the results obtained may have been unfavourably influenced by a weakening of the vaccine, brought about by repeated re-sterilisation." In no case was reinoculation done. The statistics were compiled from information furnished by officers of the Royal Army Medical Corps actually in charge of troops in the various stations; and were supplemented by reports received from the commanding officers of the various inoculated regiments. They are as follows:-- +------------------+------+-------+----------+----------+ |Numbers under |Cases.|Deaths.|Percentage|Percentage| |Observation. | | |of Cases. |of Deaths.| +------------------+------+-------+----------+----------+ |Inoculated 2835| 27 | 5 | 0.95 | 0.2 | |Uninoculated 8460| 213 | 23 | 2.5 | 0.34 | +------------------+------+-------+----------+----------+ If the inoculated had been attacked equally with the uninoculated throughout the period of observation, they would have had 71 cases instead of 27. These inoculations belong to the early part of 1899. During the rest of the year, inoculations were made in India, Egypt, and Malta: the results are given in an appendix to the Report of the Royal Army Medical Department, 1899. (See _British Medical Journal_, 21st September 1901.) The great majority of the troops tabulated were in India. Of the troops stationed at Malta, 61 were inoculated, 2456 not inoculated; among the former there were no cases, among the latter there were 17 cases and 5 deaths. In Egypt, of 4835 troops, 461 were inoculated; among these there were no cases, among the uninoculated there were 30 cases and 7 deaths. In India, of 30,353 troops, 4502 were inoculated, leaving 25,851 not inoculated; among the inoculated there were 44 cases and 9 deaths, among the non-inoculated 657 cases and 146 deaths. Taking the Indian statistics, and estimating percentage to strength, we find, amongst the inoculated, admissions 0.98, deaths 0.2; amongst the non-inoculated, admissions 2.5, deaths 0.56. The cases which occurred amongst the inoculated men were in the majority of instances of a mild character. Taking Malta, Egypt, and India together, it appears that the inoculated, if they had suffered equally with the non-inoculated, would have had 108 cases and 24 deaths, instead of 44 cases and 9 deaths. At the end of 1899, this treatment, only just out of the hands of science, was suddenly demanded for the protection of a huge army at war in a country saturated with typhoid. Still, the South African results, and other results during 1899 to 1901, show a good balance of lives saved. The following paragraphs give all results published from the beginning of 1900 to May 1902. They are put in order of publication. Doubtless a few other reports have been overlooked in compilation; but the list includes all that were easily accessible. 1. _Manchester, England._ The _British Medical Journal_, 28th April 1900, contains a note by Dr. Marsden, Medical Superintendent of the Monsall Fever Hospital, Manchester, on the inoculation of 14 out of 22 nurses engaged in nursing typhoid patients. Of the remaining 8, 4 had already had typhoid. The inoculations were made in October 1899. The following table shows the subsequent freedom from typhoid of the nursing staff:-- +-------------------------------+-----------------+--------------+ | Year. | Number of | Cases among | | |Typhoid Patients.|Nursing Staff.| +-------------------------------+-----------------+--------------+ | 1895 | 229 | 3 | | 1896 | 238 | 3 | | 1897 | 302 | 4 | | 1898 | 426 | 8 | | To end of September 1899 | 163 | 5 | |From October 1899 to March 1900| 146 | 0 | +-------------------------------+-----------------+--------------+ 2. _Ladysmith, South Africa._ The _Lancet_, 14th July 1900, contains a short note by Professor Wright, on the distribution of typhoid among the officers and men of the military garrison, during the siege of Ladysmith. The figures are as follows:-- +-------------+-------+------+----------+-------+----------+----------+ | |Number.|No. of|Proportion|No. of |Proportion| Case- | | | |Cases.|of Cases. |Deaths.|of Deaths.|mortality.| +-------------+-------+------+----------+-------+----------+----------+ |Not | | | | | | | | inoculated |10,529 | 1489 |1 in 7.07 | 329 | 1 in 32 |1 in 4.52 | |Inoculated | 1,705 | 35 |1 in 48.7 | 8 | 1 in 213 |1 in 4.4 | +-------------+-------+------+----------+-------+----------+----------+ The wide difference between the two groups, as regards the incidence of the disease, is well marked; but the case-mortality is practically the same in each group. (The statistics of the General Hospital, Ladysmith, also tell in favour of the preventive treatment: see Surgeon-Major Westcott's letter, _British Medical Journal_, 20th July 1901, in answer to Dr. Melville's letter, _British Medical Journal_, 20th April 1901.) 3. _The Portland Hospital: Modder River and Bloemfontein_. The _British Medical Journal_, 10th November 1900, contains an account by Dr. Tooth of the cases of typhoid in this hospital. Concerning the preventive treatment, he says: "The experience of my colleague Dr. Calverley and myself may be of interest, though we fear that the numbers are too few for safe generalisation. "_Personnel of the Portland Hospital._ We take first the relation of disease and inoculation among the _personnel_ of the hospital. Twenty-four non-commissioned officers, orderlies, and servants of the Portland Hospital, and 4 of the medical staff, were inoculated on the voyage out. All these showed the local symptoms at the time; that is, pain, stiffness, and local erythema; 17 also presented well-marked constitutional symptoms--general feeling of illness, fever, and headache. Of the orderlies, 9 had enteric fever subsequently. Two had refused inoculation, and both of these had the disease very severely; in fact one died. Of the inoculated cases, 5 had the disease lightly, and 2 fairly severely. One of the sisters had the disease rather severely, and she had not been inoculated. "_Officers and men admitted to the Portland Hospital._ We had under treatment at the Portland Hospital 231 cases of enteric fever, most of which came under our care at Bloemfontein. We have not included in these figures a number of patients who came in convalescent for a short time only, and on their way to the base, and who would therefore appear in the admission and discharge book of the hospital. If we did so, of course our percentages would be lower. Of these 231 patients, 53 had been inoculated at home or on the voyage out, and of them 3 died, making a percentage of deaths among the inoculated of 5.6 per cent.; 178 had not been inoculated, of whom 25 died; that is, a mortality among the non-inoculated of 14 per cent. The general mortality in enteric fever with us was 28 deaths out of 231 cases; that is, 12.1 per cent., which seems to compare favourably with the experience of the London hospitals. "It is interesting to record our experience among the officers taken separately. Thirty-three officers were admitted with enteric fever; 21 had been inoculated; that is, 63.6 per cent.; a much larger percentage than among the men. Only one of these officers died, and he had not been inoculated. "These figures are small, but such as they are they are significant, and they dispose us to look with favour upon inoculation. So also does our clinical experience with our patients, for among the inoculated the disease seemed to run a milder course." 4. _No. 9 General Hospital, Bloemfontein._ The _Medical Chronicle_ for January 1901 contains an account, by Dr. J. W. Smith, of the work of this hospital. He says: "The general impression amongst the medical officers in our hospital was that a single inoculation probably did not confer an immunity lasting very long--the lapse of time differing in individuals--and also that there was a tendency in the cases of enteric in inoculated patients to abort at the end of ten or fourteen days. I should say, however, that a very considerable number of our detachment who had been inoculated suffered from enteric, of whom 4 at least died. Of the medical staff, the only member of the junior staff who had not been inoculated died of enteric." 5. _Scottish National Red Cross Hospital, Kroonstadt._ The _British Medical Journal_, 12th January 1901, contains an account of the work of this hospital by Surgeon-Colonel Cayley, Officer in Charge. He says: "The first section of the hospital, consisting of 61 persons--officers, nursing sisters, and establishment--left Southampton on 21st April 1900. During the voyage out, all except 4 were inoculated twice, at an interval of about ten days; 2 were inoculated once; and 2 (who had had typhoid) were not inoculated. Immediately we reached the Cape, the hospital was sent up to Kroonstadt in the Orange River Colony, and remained there as a stationary hospital till the middle of October. During this period there were always many cases of enteric under treatment in hospital. Further, some of the medical officers and student orderlies had charge of the Kroonstadt Hotel temporary hospital, which was crowded up with enteric cases; and the nursing sisters, for three weeks, did duty in the military hospitals at Bloemfontein in May and June, when enteric fever was at its worst. There was not a single case of enteric among the _personnel_ of this first section of the hospital. "The second section of the hospital--medical officers, nurses, and establishment, 82 in all--left Southampton in May 1900. On board ship nearly all of them were inoculated, but many of them only once. The material for inoculation had been on board for some time, and was not so fresh as in the first instance. Of this second section, 1 nurse had enteric at Kroonstadt. She was the only one, out of a total of 36 nurses, who suffered from enteric; and she was the only nurse who was not inoculated, excepting the 2 who were protected by a previous attack of enteric. A third section of the hospital, consisting of 4 medical officers and 16 nurses, went out in July; they were all inoculated, and none of them had enteric. "Of the second section, 5 orderlies had enteric fever at Kroonstadt, of whom 2 died. Of these 5, there were 2 inoculated (once) and 3 non-inoculated. Of the 2 who died, 1 had been once inoculated, the other had not been inoculated." 6. _Meerut, India._ The _British Medical Journal_, 9th February 1901, gives a short note by Professor Wright on inoculations in the 15th Hussars. He says: "Through the kindness of Lieutenant-General Sir George Luck, commanding the Bengal Army, I am permitted to publish the following officially compiled statistics, dealing with the effects of anti-typhoid inoculations in the case of the 15th Hussars:-- _From 22nd October 1899 to 22nd October 1900._ +---------------+---------+-----------+------+-------+ | | | | | | | |Strength.|Inoculated.|Cases.|Deaths.| +---------------+---------+-----------+------+-------+ |Officers | 22 | 19 | 0 | 0 | |N.C.O. and Men | 481 | 317 | 2 | 1 | |Women | 36 | 24 | 0 | 0 | +---------------+---------+-----------+------+-------+ +---------------+-----------+------+-------+ | |Not | | | | |Inoculated.|Cases.|Deaths.| +---------------+-----------+------+-------+ |Officers | 3 | 0 | 0 | |N.C.O. and Men | 164 | 11 | 6 | |Women | 12 | 0 | 0 | +---------------+-----------+------+-------+ It would thus appear that the incidence of enteric in the inoculated was represented by 0.55 per cent., and the mortality by 0.27 per cent.; while the incidence in the uninoculated was 6.14 per cent., and the death-rate 3.35 per cent." If the inoculated had suffered equally with the uninoculated, they would have had 22 cases with 11 deaths, instead of 2 cases with 1 death. 7. _The Edinburgh Hospital, South Africa._ The _Scottish Medical and Surgical Journal_, March 1901, contains an account of the work of the Edinburgh Hospital, by Dr. Francis Boyd. Of the staff, 58 were inoculated (27 once, and 31 twice). Among these 58, there were 9 cases of typhoid fever, with I death, in a patient who had old mitral disease. "Our experience has been that, while inoculation appears to modify the disease, completely modified attacks are met with in the uninoculated. Again, very severe attacks, with complications and relapse, occur in those who have been inoculated. One cannot from this conclude that inoculation has been valueless, for had not the patient been inoculated, the attack might have been still more severe." 8. _Egypt and Cyprus._ The _British Medical Journal_, 4th May 1901, gives a short note by Professor Wright on inoculations during 1901 in Egypt and Cyprus. He says: "I am indebted to the kindness of Colonel W. J. Fawcett, R.A.M.C., Principal Medical Officer in Egypt, for the following statistics dealing with the incidence of enteric fever, and the mortality from the disease, for the year 1900, in the inoculated and uninoculated among the British troops in Egypt and Cyprus:-- +------------------------------------------------------------------+ | |Average Annual|Cases.|Deaths.|Percentage|Percentage | | | Strength. | | | of Cases.| of Deaths.| |-------------+--------------+------+-------+----------+-----------| |Uninoculated | 2669 | 68 | 10 | 2.50 | 0.40 | |Inoculated | 720 | 1 | 1 | 0.14 | 0.14 | +------------------------------------------------------------------+ These figures testify to a nineteen-fold reduction in the number of attacks of enteric fever, and to a threefold reduction in the number of deaths from that disease, among the inoculated.... The only case which occurred among the inoculated was that of a patient admitted to hospital on the thirty-third day after inoculation. It would seem that the disease was in this case contracted before anything in the nature of protection had been established by the inoculation." 9. _Imperial Yeomanry Hospital, Pretoria._ Dr. Rolleston, Consulting Physician to this hospital, writes in the _British Medical Journal_, 5th October 1901: "Among the _personnel_ of the hospital (17 medical officers, 50 nursing sisters, 83 orderlies, etc.), total, 150, there were 22 cases of enteric fever, or an incidence of 14.6 per cent. Of the 150, 35 were inoculated, and of these, 6, or 17 per cent., suffered from enteric; while, of 115 non-inoculated members of the _personnel_, 16, or 13.9 per cent., suffered from enteric fever; the percentage is therefore higher among the inoculated. There were 2 deaths, both in non-inoculated patients. In 100 cases of enteric fever among non-commissioned officers and men, taken mainly from convalescent patients, only 8 had been previously inoculated; there were 3 fatal cases, all among non-inoculated patients. Among 42 officers who had enteric, no fewer than 19 had been previously inoculated; 6 of these 19 cases were severe in character, but none were fatal; of the 23 non-inoculated cases, 7 were severe, and of these 7, 3 ended fatally. The interval between inoculation and the subsequent incidence of enteric fever varied between one and twenty-one months, but in only four instances was the interval less than six months. The average interval between inoculation and the onset of enteric fever in these 19 cases was thirty-eight weeks. "As far as these scanty figures go, they point to the conclusion (1) that anti-typhoid inoculation does not absolutely protect against a future attack of typhoid fever; (2) that when enteric occurs in an inoculated person, there is, as a rule, an interval of about six months; (3) that inoculation protects against a fatal termination to the disease." 10. _Richmond Asylum, Dublin._ The _British Medical_ _Journal_, 26th October 1901, contains a note by Professor Wright on an outbreak of typhoid in this asylum during August to December 1900. Inoculations were begun on 6th September, by Dr. Cullinan, and by 30th November 511 persons were inoculated. After careful criticism of all doubtful cases, Professor Wright gives the following figures:-- _Comparative Incidence of Typhoid Fever in Inoculated and Non-Inoculated, calculated upon the average strength of the representative groups during the period intervening between the commencement of the inoculations and the termination of the epidemic._ +--------------+---------+-------+-------+----------+----------+ | |Average |Cases. |Deaths.|Percentage|Percentage| | |Strength.| | |of Cases. |of Deaths.| +--------------+---------+-------+-------+----------+----------+ |Uninoculated | 298 |30(-1?)| 4 | 10.1 | 1.3 | |Inoculated | 339 | 5(+1?)| 1 | 1.3 | 0.3 | +--------------+---------+-------+-------+----------+----------+ "It may be noted," he says, "that the result is in conformity with that of all the statistical returns of anti-typhoid inoculation which have reached me." 11. _Deelfontein._ The _Lancet_, 18th January 1902, contains a paper by Dr. Washbourn and Dr. Andrew Elliot, on 262 cases of typhoid fever in the Imperial Yeomanry Hospital at Deelfontein during the year March 1900 to March 1901. (See Dr. Washbourn's earlier letter, _Brit. Med. Jour._, 16th June 1900.) They say: "In 211 of our cases, it was definitely recorded whether the patient had been inoculated or not: 186 of these cases had not been inoculated, with 20 deaths, or a mortality of 10.7 per cent.; 25 had been inoculated, with 4 deaths, or a mortality of 16 per cent. The mortality was thus higher among the inoculated than among the non-inoculated." Of the _personnel_ of the hospital, there were 59 inoculated, with 4 cases, and 25 not inoculated, with 4 cases. 12. _Winburg._ The _Lancet_, 5th April 1902, contains a short note by Professor Wright, on the 5th Battalion, Manchester Regiment. He says: "In view of the dearth of statistics bearing on the incidence of typhoid fever in South Africa in inoculated and uninoculated persons respectively, the following, for which I am indebted to Lieutenant J. W. West, R.A.M.C., Winburg, Orange River Colony, may not be entirely without interest. The statistics here in question give the results obtained in the case of the 5th Battalion, Manchester Regiment, for the six months which have elapsed since their landing in South Africa. The figures, which relate to a total strength of 747 men and officers under observation, are as follows:-- +--------------+---------+-------+-------+----------+----------+ | | Number. |Cases. |Deaths.|Percentage|Percentage| | | | | |of Cases. |of Deaths.| +--------------+---------+-------+-------+----------+----------+ |Uninoculated | 547 | 23 | 7 | 4.2 | 1 in 3.3 | |Inoculated | 200 | 3 | 0 | 1.5 | 0 | +--------------+---------+-------+-------+----------+----------+ "The three attacks in the inoculated are reported to have been of exceptionally mild type, contrasting in a striking manner with the severe attacks which occurred in the uninoculated. At the time of sending in the report, some of the uninoculated patients were 'not yet out of danger.'" * * * * * Certainly, these instances show a good balance of lives saved, not only under the adverse conditions of the war, but also in Egypt, India, and the United Kingdom. But the bacteriological work on typhoid fever has been directed also to the working out of a very different problem: and that is the method of diagnosis which is called "Widal's reaction." The practical uses of this reaction are of the utmost importance. It is the outcome of work in different parts of the world--by Wright and Semple and Durham in England, Chantemesse and Widal in France, Pfeiffer and Kolle and Grüber in Germany, and many more. The first systematic study of it was made by Durham and Pfeiffer; and Widal's name is especially associated with the application of their work to the uses of practice. Admirable accounts of the whole subject are given by Dr. Cabot in his book, _The Serum-Diagnosis of Disease_ (Longmans, 1899), and by Mr. Foulerton in the _Middlesex Hospital Journal_, October 1899 and July 1901. Widal's reaction is surely one of the fairy tales of science. The bacteriologist works not with anything so gross as a drop of blood, but with a drop of blood fifty or more times diluted; one drop of this dilution is enough for his purpose. Take, for instance, an obscure case suspected to be typhoid fever: a drop of blood taken from the finger is diluted fifty or more times, that the perfect delicacy of the test may be ensured; a drop of this dilution is mixed with a drop of nutrient fluid containing living typhoid bacilli, and a drop of this mixture of blood and bacilli is watched under the microscope:-- "The motility of the bacilli is instantaneously or very quickly arrested, and in a few minutes the bacilli begin to aggregate together into clumps, and by the end of the half-hour there will be very few isolated bacilli visible. In less marked cases, the motility of the bacilli does not cease for some minutes; while in the least marked ones the motility of the bacilli may never be completely arrested, but they are always more or less sluggish, while clumping ought to be quite distinct by the end of the half-hour." The result of this clumping is also plainly visible to the naked eye, by the subsidence of the agglutinated bacteria to the bottom of the containing vessel: and thus an easy practical mode of diagnosis is afforded by it. As with typhoid, so with Malta fever, cholera, and some other infective diseases. And the unimaginable fineness of this reaction goes far beyond the time of the disease. Months, even years, after recovery from typhoid, a fiftieth part of a drop of the blood will still give Widal's reaction: and it has been obtained in an infant whose mother had typhoid before it was born. A drop of dried blood, from a case suspected to be typhoid, may be sent a hundred miles by post to be tested; and typhoid, like diphtheria, may now be submitted to the judgment of an expert far away, and the answer telegraphed back. It would be difficult to exaggerate the practical importance of this reaction for the early diagnosis of cases of typhoid fever, especially those cases that appear, at the onset, not severe. MALTA FEVER The specific organism of Malta fever (Mediterranean fever), the _bacillus Melitensis_, was discovered in 1887 by Surgeon-Major David Bruce, of the Army Medical Staff. Its nature and action were proved by the inoculation of monkeys. The use of Widal's reaction is of great value in this disease:-- "The diagnosis of Malta fever from typhoid is, of course, a highly important practical matter. It is exceedingly difficult in the early stages." (Manson, _loc. cit._) As with typhoid, so with Malta fever, Netley led the way to the discovery of an immunising serum. In the course of the work, one of the discoverers was by accident infected with the disease:-- "He was indisposed when he went to Maidstone to undertake anti-typhoid vaccination, and after fighting against his illness for some days, he was obliged to return to Netley on 9th October. Examination of blood-serum (Widal's reaction) showed that he was suffering from Malta fever. It appears that he had scratched his hand with a hypodermic needle on 17th September, when immunising a horse for the preparation of serum-protective against Malta fever; and his blood, when examined, had a typical reaction on the micrococcus of Malta fever in 1000-fold dilution. The horse, which has been immunised for Malta fever for the last eight months, was immediately bled, and we are informed that the patient has now had two injections, each of 30 cub. cm. of the serum. He is doing well, and it is hoped that the attack has been cut short." (_British Medical Journal_, 16th October 1897.) About fifty cases had up to September 1899 been treated at Netley "with marked benefit: whereas they found that all drug-treatment failed, the antitoxin treatment had been generally successful."[36] A good instance of the value of the serum-treatment of Malta fever is published in the _Lancet_, 15th April 1899. For a later account of this treatment and of its efficacy, see the _Philadelphia Medical Journal_, 24th November 1900. [36] For the whole subject, see _Lancet_, 9th September 1899, paper by Surgeon-Major Birt and Surgeon-Captain Lamb. Two other cases of accidental inoculation occurred at Netley. Another point is noted by Sir Patrick Manson, in his recent Lane Lectures (Constable, 1905). "For some time back," he says, "a commission of experts, working under the direction of the Royal Society, has been studying this disease in Malta. The commission has accumulated much detailed information; but the most important observation it has published is the fact that a large percentage of the goats in Malta are infected with _Micrococcus melitensis_, and that the milk of the infected goats contains the bacterium. May not this account for the great prevalence of Mediterranean fever there and in other places having perhaps a similar milk-supply?" X THE MOSQUITO: MALARIA, YELLOW FEVER, FILARIASIS Within the last few years, it has been proved that the mosquito is an intermediate host, between man and man, of malaria, yellow fever, and filariasis (elephantiasis).[37] Just as the grosser parasites, the tapeworms, must alternate between man and certain animals, and cannot otherwise go through their own life-changes and reproduce their kind, so the micro-parasites that are the cause of malaria alternate between man and the mosquito, having the mosquito as an intermediate host. These organisms, once they get into the mosquito, pick out certain structures, and there carry out a definite cyclical phase of their lives, whereby their progeny make their way into the stylets of the mosquito, and so get back to man, who is their "definite host." Thus, malaria is not, strictly speaking, a disease of man; it is one phase in man of micro-organisms that have another phase in mosquitoes. So also with filariasis; the filariæ in man, their ova, and their embryo-worms, are one phase of filariasis; and the embryo-worms in certain structures of the mosquito are another phase. The _plasmodium malariæ_ and the _filaria_ are instances of a law of animal life that holds good also of plant life:-- "All plants and animals possess parasites, and thousands of different species of parasites have been closely studied by science; we therefore know much about their general ways of life. As a rule, a particular species of parasite can live only in the particular species of animal in which, by the evolution of ages, it has acquired the power of living. It is therefore not enough for the parasites of an individual animal--say a man--to be able to multiply within that individual, but they must also make arrangements, so to speak, for their progeny to enter into and infect other individuals of the same species. They cannot live for ever in one individual; they must spread in some way or other to other individuals. "The shifts made by parasites to meet this requirement of their nature are many and various, and constitute one of the wonders of nature. Some scatter their spores and eggs broadcast in the soil, water, or air, as it were in the hope that some of them will alight by accident on a plant or animal suitable for their future growth. Many parasites employ, in various ways, a second species of animal as a go-between. Thus, some tapeworms, and the worms which cause trichinosis, spend a part of their lives in the flesh of swine, and transfer themselves to human beings when the latter eat this flesh. To complete the cycle, the parasites return to swine from human offal; so that they propagate alternately from men to swine, and from swine to men. The blood-parasites which cause the deadly tsetse-fly disease among cattle in South Africa are transferred from one ox to another on the proboscis of the ox-biting or tsetse-fly. The progeny of the flukes of sheep enter a kind of snail, which spreads the parasites upon grass. The progeny of the guinea-worm of man enter a water-flea. The progeny of the parasites which cause Texas cattle-fever, and which are very like the malarial parasites, live in cattle-ticks, and are transferred by the young of these ticks into healthy cattle." (Ross, _Malarial Fever_, 1902.) [37] For Dr. Graham's experiments at Beyrout, which seem to prove that the mosquito can also convey dengue or dandy-fever, see the _New York Medical Record_, 8th February 1902. 1. MALARIA The _plasmodium malariæ_ was discovered by Laveran in 1880, in the blood of malarial patients. For many years his work stopped there, because it was impossible to find the _plasmodium_ in animals: "the difficulties surrounding the subject were so great that this discovery seemed to be almost hopeless." In 1894, Sir Patrick Manson--who had proved mosquitoes to be the intermediate host in the case of the parasitic nematode _filaria_--suggested, as a working theory of malaria, that the plasmodium was carried by mosquitoes. This belief, not itself new, he made current coin. He observed that there is a flagellate form of the plasmodium, which only comes into existence after the blood has left the body: and he suggested that the flagella might develop in the mosquito as an intermediate host, a halfway-house between man and man. Then, in 1895, Ross set to work in India, keeping and feeding vast numbers of mosquitoes on malarial blood; and for two years without any conclusive result. About this time came MacCallum's observations, at the Johns Hopkins University, on a parasitic organism, _halteridium_, closely allied to the plasmodium malariæ; he showed that the flagella of the halteridium are organs of impregnation, having observed that the non-flagellated form, which he regarded as the female, after receiving one of the flagella, changed shape, and became motile. In August 1897, Ross found bodies, containing pigment like that of the malarial parasite, in the outer coat of the stomach of one kind of mosquito, the grey or dapple-winged mosquito, _Anopheles maculipennis_, that had been fed on malarial blood. In February 1898, he was put on special duty under the Sanitary Commissioner with the Government of India, to study malaria, and started work again in Calcutta:-- "Arriving there at a non-fever season, he took up the study of what may be called 'bird malaria.' In birds, two parasites have become well known--(1) the halteridium, (2) the proteosoma of Labbé. Both have flagellated forms, and both are closely allied to the plasmodium malariæ. Using grey mosquitoes and proteosoma-infected birds, Ross showed by a large number of observations that it was only from blood containing the proteosoma that pigmented cells in the grey mosquito could be got; therefore that this cell is derived from the proteosoma, and is an evolutionary stage of that parasite. Next, Ross proceeded to find out its exact location, and found that it lay among the muscular fibres of the wall of the mosquito's stomach. It grows large (40-70 micro-millimetres) and protrudes from the external surface of the stomach, which under the microscope appears as if covered with minute warts." (Manson, at Edinburgh meeting of British Medical Association, 1898.) These pigmented spherical cells give issue to innumerable swarms of spindle-shaped bodies, "germinal rods"; and in infected mosquitoes Ross found these rods, in the glands that communicate with the proboscis. Thus the evidence was complete, that the plasmodium malariæ, like many other parasites, has a special intermediate host for its intermediate stage of development; and that this host is the dapple-winged mosquito. It is impossible to over-estimate the infinite delicacy and difficulty of Ross's work; for instance, in his "Abstract of Recent Experiments with Grey Mosquitoes," he says that "out of 245 grey mosquitoes fed on birds with proteosoma, 178, or 72 per cent., contained pigmented cells; out of 249 fed on blood containing halteridium, immature proteosoma, &c., not one contained a single pigmented cell." Another time (April 1898) he counted these pigment-cells under the microscope:-- "Ten mosquitoes fed on the sparrow with numerous proteosoma contained 1009 pigmented cells, or an average of 101 each. Ten mosquitoes fed on the sparrow with moderate proteosoma contained 292 pigmented cells, or an average of 29 each. The mosquitoes fed on the sparrow with no proteosoma contained no pigmented cells." Finally, he completed the circle of development by infecting healthy sparrows by causing mosquitoes to bite them. In 1899, there went out a German Commission to German East Africa, a Royal Society's Commission to British Central Africa, and an expedition from the Liverpool School of Tropical Medicine; in 1900, another German Commission, this time to the East Indies, and another expedition from the Liverpool School; by July 1901, the Liverpool School was organising its seventh expedition. Italy, of course, has given infinite study to the disease:-- "It has been decided that, in addition to the stations of observation and experiment in the provinces of Rome, Milan, Cremona, Mantua, Gercara, Foggia, Lecce, others shall be established in the provinces of Udine, Verona, Vicenza, Padua, Ravenna, Pisa, Basilicata, and Syracuse. Besides epidemiological researches, applications on a large scale will be made of preventive measures for the protection of the agricultural population against the scourge. Another extensive experiment on the prophylaxis of malaria will be made on the Emilian littoral. Moreover, in all the malarious regions of the Italian peninsula the provincial and communal administrations and many private persons will co-operate in the application of preventive measures. From all this it may be gathered that during the summer and autumn the war against malaria will be carried on in Italy with great vigour and thoroughness." (_British Medical Journal_, 6th July 1901.) In India, the work started in 1900 by the Royal Society Commissioners, and by the Nagpur Conference, has been widely extended; especially by such researches as those of Major Buchanan, I.M.S., Superintendent of the Central Jail, Nagpur. The following paragraph, from the report of the Sanitary Commissioner with the Government of India, refers to Major Buchanan's published work, _Malarial Fevers and Malarial Parasites in India_:-- "A remarkable note is struck at the outset, in the acknowledgment made, by the author, of the capable assistance rendered in these researches by several of his Burmese prisoners, whom he trained to the use of the microscope, and who soon became expert in detecting and distinguishing the various kinds of parasites.... Besides a systematic clinical account of the different forms of fever and the associated parasites, which is the first attempt of the kind in India, there are a summary of the facts showing the relation of the seasonal prevalence of _Anopheles_ to the incidence of attacks; experiments exhibiting the protective effects of mosquito-curtains; inoculation-experiments; researches on the blood-parasites of birds; and many other points.... Nor can we pause to notice the many attempts now being made by health officers and others to pursue the methods of prophylaxis indicated; these efforts are necessarily in the tentative stage, but, so far, and especially where carried out in connection with small communities and institutions, they are giving promise of gratifying success." The famous experiment made by Dr. Sambon and Dr. Low in 1900, must be recalled here:-- "Dr. Luigi Sambon and Dr. G. C. Low, both connected with the London School of Tropical Medicine, volunteered to live from June till October, that is to say, through what may be called the height of the malaria season, in a part of the Campagna near Ostia, which is so infested by the disease that no one who spends a night there under ordinary conditions escapes the effect of the poison. Dr. Sambon, Dr. Low, Signor Terzi, and their servants, have now exposed themselves to the pestilential influence of this valley of the shadow of death for over two months. They live in a mosquito-proof hut; they take no quinine or other drug which might be regarded as prophylactic. Not one of the experimenting party has the least sign of infection.[38]... "What for practical purposes may be regarded as an experiment of the same kind is being conducted in West Africa. Dr. Elliot, a member of the Liverpool expedition sent to Nigeria some time ago to investigate the subject of malarial fever, has recently returned to this country. He reports that the members of the expedition have been perfectly well, although they have spent four months in some of the most malarious spots. They lived practically amongst marshes and other places hitherto supposed to be the most deadly. They have not kept the fever off by the use of quinine, and they attribute their immunity to the careful use of mosquito-nets at night." (_British Medical Journal_, 22nd September 1900.) [38] Sir Patrick Manson, in the _British Medical Journal_, 29th September 1900, gives the following account of this experiment:--"A wooden hut, constructed in England, was shipped to Italy and erected in the Roman Campagna, at a spot ascertained by Dr. L. Sambon, after careful inquiry, to be intensely malarial, where the permanent inhabitants all suffer from malarial cachexia, and where the field-labourers, who come from healthy parts of Italy to reap the harvest, after a short time all contract fever. This fever-haunted spot is in the King of Italy's hunting-ground near Ostia, at the mouth of the Tiber. It is waterlogged and jungly, and teems with insect life. The only protection employed against mosquito-bite and fever by the experimenters who occupied this hut was mosquito-netting, wire screens in doors and windows, and, by way of extra precaution, mosquito-nets round their beds. Not a grain of quinine was taken. They go about the country quite freely--always, of course, with an eye on _Anopheles_--during the day, but are careful to be indoors from sunset to sunrise. Up to 21st September, the date of Dr. Sambon's last letter to me, the experimenters and their servants had enjoyed perfect health, in marked contrast to their neighbours, who were all of them either ill with fever, or had suffered malarial attacks." A similar "experiment," of the utmost importance, was made in 1900 by Professor Grassi. It concerned the workmen and their families along the Battipaglia-Reggio railway, 104 in all, including 33 children. The great majority of them had suffered from malaria in the preceding year; and only 11, including 4 children, had never suffered from it. Pending the arrival of the malarial season, quinine was given to all who needed it. The first _Anopheles_ with its salivary glands infected was found on 14th June. Twelve days later came a case of malaria outside the "zone of experiment," in a person who had never had malaria before. The twelve days correspond to the incubation-period after infection. _Anopheles_ having come, and the malarial season with him, the experiment was begun. The houses were carefully protected with wire netting, chimneys and all; the _siesta_ was taken under wire netting; the workmen, if they were out in the evening or at night, wore veils and gloves; and _Anopheles_ was to be killed wherever he was found. Quinine was altogether given up and forbidden, except for three workmen who had escaped or evaded its use before June, and had, indeed, never before been treated with quinine; one of them, moreover, had been sleeping outside the zone of experiment in July. Except these three, all the 104 and their doctors remained absolutely free from malaria up to 16th September, the date of Professor Grassi's report:-- "Rightly to estimate the value of these facts, it is necessary briefly to describe the surroundings of the protected area. Towards the north, coming from Battipaglia, three railway cottages are situated, at a distance of 1, 2, and 3 kilometres respectively. The 25 inhabitants of these cottages, although they were put under the tonic and quinine treatment in the non-malarial season, all without exception were taken ill with malarial fevers, in many cases obstinate." Experiments of voluntary exposure to bite from an infected mosquito were made at or about this time, in London, New York, Italy, and India. The London "consignment" of mosquitoes had been allowed to bite a malaria-patient in Rome. The experiment had to be very carefully planned:-- "To have sent mosquitoes infected with malignant tertian parasites might have endangered the life of the subject of the experiment; and quartan-infected insects might have conferred a type of disease which, though not endangering life, is extremely difficult to eradicate. The cases, therefore, on which the experimental insects were fed had to be examples of pure benign tertian--a type of case not readily met with in Rome during the height of the malarial season; the absolute purity of the infection could be ascertained only by repeated and careful microscopic examination of the blood of the patient." (_British Medical Journal_, 29th September 1900.) The mosquitoes were forwarded, through the British Embassy in Rome, to the London School of Tropical Medicine. The two brave gentlemen who let themselves be bitten by some thirty of the mosquitoes were in due time attacked by malaria, and the tertian forms of the parasite were found in their blood. Nine months later, one of them had a relapse, and the parasite was again found in his blood. It is not possible to sum up the wealth of work on malaria published in 1900-1901. Good accounts of it are in the Transactions of the Section of Tropical Diseases, at the Annual Meeting of the British Medical Association (Cheltenham, 1901), and in the Thompson Yates Laboratories Reports, vol. iii., pt. 2, 1901. Everything had to be studied: not only the nature and action of the _plasmodium_ in all its phases, but also the whole natural history and habits of the _Anopheles_ of different countries; and, above all, the incidence of the disease on natives and on Europeans in China, India, and Africa. All that can be done here is to try to indicate the principal lines followed in the present world-wide campaign against malaria. The following paragraphs are taken mostly from the accounts given by Dr. Christophers and Dr. Annett, in the Thompson Yates Laboratories Report, 1901:-- 1. _Elimination of the Infection at its Source._ This is the method employed with success by Professor Koch in New Guinea, viz., to search out all cases of malaria (the concealed ones in particular), and to render them harmless by curing them with quinine. At Stephansort, by thus hunting up all infected cases, and as it were, sterilising them by the systematic administration of quinine, he was able to achieve a great reduction of the disease in the next malarial season, even under adverse conditions. He says, in his report to the German Government: "The results of our experiment, which has lasted nearly six months, have been so uniform and unequivocal that they cannot be regarded as accidental. We may assume that it is directly owing to the measures we have adopted that malaria here has, in a comparatively short time, almost disappeared." This method, of course, is applicable only in small communities; and, within these limits, it may become one of the most valuable of all methods, being, like the quality of mercy, a blessing both to him who gives and to him who taketh. But it cannot be practised on a vast scale. This difficulty is well put by Sir William MacGregor, K.C.M.G., Governor of Lagos, West Africa:-- "In all probability, the day will come before long, when newly-appointed officers for places like Lagos will have to undergo a test as to whether they can tolerate quinine or not. A man that cannot, or a man that will not, take quinine, should not be sent to or remain in a malarial country, as he will be doing so at the risk of his own life, _and to the danger of others_.... The great difficulty is how to extend this treatment beyond the service, more particularly to the uneducated masses of the natives. It is simply impossible to protect the whole population by quinine administered as a prophylactic. In the first place, the great mass of natives would not take the medicine; and, in the second place, the Government could not afford to pay for the 70 tons of quinine a year that would be required to give even a daily grain dose to each of 3,000,000 of people." 2. _Segregation of Europeans from Natives._ This method is strongly advocated by the members of the Nigeria Expedition of the Liverpool School (1900). The distance of removal to half a mile is considered sufficient: "Considerable evidence has now been accumulated to prove that the distance which is traversed by a mosquito is never very great, and extremely rarely reaches so much as half a mile." The arguments in favour of this method of "segregation" are of so great interest that they must be put here at some length. The drawback is that the method cannot be followed everywhere to its logical issue without some risk of giving offence, of seeming to abandon the native, of damaging commerce, and so forth. But, short of this, much might be done for the protection of Europeans in Africa:-- "This method is a corollary of the discovery that native children in Africa practically all contain the malaria parasite, and are the source from which Europeans derive malaria. Koch showed in New Guinea that in most places infection was very prevalent in native children, so much so that in some villages 100 per cent. of those examined contained parasites. He also showed that, as the children increased in age, immunity was produced, so that in the case of adults a marked immunity was present, and malarial infection was absent. The Malaria Commission showed, independently, that a condition of universal infection existed among the children of tropical Africa, associated with an immunity of the adults. This infection in children had many remarkable characteristics. The children were in apparent health, but often contained large numbers of parasites, and a small proportion only of the children failed to show some degree of infection.... The Liverpool School Expedition found a similar condition of affairs in all parts of Nigeria visited by them. "With a knowledge of the ubiquity of native malaria, the method of infection of Europeans becomes abundantly clear. The reputed unhealthiness or healthiness of stations is seen at once to be dependent on the proximity or non-proximity of native huts. The attack of malaria after a tour up-country, the malaria at military stations like Prah-su, the abundance of malaria on railways, are all explicable when the extraordinary condition of universal native infection is appreciated. It is evident that, could Europeans avoid the close proximity of native huts, they would do away with a very obvious and great source of infection.... When it is understood that each of these huts certainly contains many children with parasites in their blood, and also scores or hundreds of _Anopheles_ to carry the infection, then the frequency with which Europeans suffer from malaria is scarcely to be wondered at.... The accompanying plan is that of a new railway settlement on the Sierra Leone Railway. Miles of land free from huts exist along the line, but the close neighbourhood of native huts has been selected. At the time of building of these quarters, it lay in the power of the engineers to have a malaria-free settlement; instead of which, by the non-observance of a simple fact, the station is most malarious: in this particular instance, much ingenuity has been shown in providing each set of European quarters with plenty of malarial infection. In towns only is there any difficulty in carrying out the principle of segregation. In two instances, however, this has been carried out in towns, with the result that the segregated communities of Europeans are notoriously the most healthy on the West Coast. Even when no scheme of complete segregation can be carried out, the principle should always be borne in mind, and, whenever opportunity offers, huts should be removed, and European houses built in the open.... It is almost universally the rule in West Africa to find European houses built round by native quarters, a practice which long experience in India has taught Europeans to avoid carefully. At Old Calabar, many of the factories are almost surrounded, except in front, by native habitations; similarly, at Egwanga, the small native town is built by the side and back of one of the factories. Also at the Niger Company's factory at Lokoja, the native houses are very close up to the Company's boundary railings. Akassa engineers' quarters may be, again, mentioned as an example where the engineering artisans, chiefly natives of Lagos, Accra, and Sierra Leone, are housed with their families alongside the European house. A large proportion of these native children were found by us to contain malarial parasites. Similarly also at Asaba, the proximity of the barracks of the Hausa soldiers, who have their wives and children with them, is a dangerous menace to the officers at the Force House. "Examples of the opposite condition of affairs might also be given. For instance, at Old Calabar, the Government offices and Consulate, Vice-Consulate, and medical house, are comparatively free from malarial fever; it having been established that the natives shall not build on the European side of the creek separating the two slopes on which the native town and European quarters are built. This creek is at a distance of about half a mile from the houses mentioned." It is plain, from these and other instances given by the members of the Nigeria Expedition, that a modified sort of "segregation" can be effected in many places, without any injury either to native feelings, or to politics, or to commerce; and that by such segregation the risk of malaria among Europeans in Africa would be diminished. 3. _Protection against Anopheles._ Manson, in his _Tropical Diseases_ (1905), says, "The question is often asked, Is there any other way by which malaria can be contracted than through a mosquito-bite? For many reasons, I believe not. It is difficult to prove a negative; but, so far, there is no observation capable of bearing investigation that would lead us to suppose that malaria can be acquired, under natural conditions, except by mosquito-bite," All authorities are agreed that, practically, the fight against malaria and the fight against _Anopheles_ are one and the same thing; and the experiments by Sambon, Low, and Grassi, show what can be done, in this war against the mosquito, by way of defence. But what is practicable in Italy might not be generally practicable on the West African coast; as Sir William MacGregor says of Lagos:-- "It is not likely that in a place like Lagos as good results can be obtained from the use of mosquito-proof netting as in Italy. One great objection to it here is the serious and highly disagreeable way it checks ventilation. This is a difficulty that cannot be fully brought home to one in a cold climate. But, in a low-lying, hot, and moist locality like Lagos, it comes to be a choice of evils, to sit inside the netting stewed and suffocated, or to be worried and poisoned by mosquitoes outside. The netting is hardly a feasible remedy as regards native houses. It is not possible to protect even European quarters completely by it. Few officers or others are so occupied that they could spend the day in a mosquito-proof room. Certain it is that any man that suffers from the singular delusion that mosquitoes bite only during the night, would have a speedy cure by spending a few days, or even a few hours, in Lagos. Operations here (September 1901) are being limited to supplying one mosquito-proof room to the quarters of each officer. In this he will be able to spend the evening free from mosquitoes if he chooses to do so. The European wards of the hospital are similarly protected." The European in Africa, as Ross says, is generally neglectful of his health; and the "unhealthiness" of the African coast is to some extent due to the life that men lead there:-- "Let us compare the habits of a European in a business-house in Calcutta with the habits of a European in West Africa. In Calcutta he sleeps under a punkah or mosquito-net, or both; he dresses and breakfasts under a punkah; in the evening he takes vigorous exercise, and he dines under a punkah. He wears the lightest possible clothing, he lives in a solid, cool, airy house, and he obtains very good food; once in five or six years, he returns to Europe for leave.... In Africa, the houses are frequently very bad; in Freetown, for instance, they are the same as the houses of natives, and are mingled with them. The Anglo-African seems to imagine that he can live in the tropics in the same manner as he lives in England. He seldom uses a punkah, except perhaps for an hour at dinner-time, and, not seldom, he neglects even the mosquito-net. The food is often, or generally, execrable. Owing to the frequent absence of gymkhanas and clubs, the exile obtains little suitable exercise." But whatever risks the old resident may choose to take, the newcomer can at least use a proper and efficient mosquito-net at night, and avoid sleeping in a native house, and protect himself in these and the like ways against malaria. 4. _The keeping down of Anopheles._ The breeding places of _Anopheles_ are ponds, swamps, and puddles, roadside ditches, tanks, and cisterns, old disused canoes, and the like collections of stagnant water: also the smaller receptacles that are more generally occupied by _Culex_, such as broken bottles, old tins, pots, and calabashes, and barrels, whatever will hold water--all the débris and broken rubbish round huts or houses. In all these places, _Anopheles'_ eggs or larvæ are found; and, with practice, it is easy to detect them. Of course, it is not easy to wage war against the adult mosquito: the work is, _Venienti occurrere morbo_, to organise gangs of workmen, or of prison labour, and "mosquito brigades"; to clear the ground of cartloads of old biscuit-tins, broken gin-bottles, and other dust-heap things, in and around the place; to cover-in the cisterns, rain-barrels, and wells; to clean pools and duck-ponds of weed, and stock them with minnows; to put a film of kerosene to the puddles, or sweep them out, or fill them up and turf them over; everywhere, to drain, and level, and clean-up the surface soil; and everywhere, by these and the like methods, to break the cycle of the life of the _plasmodium malariæ_:-- "Draining and cultivation where the land will repay the expenditure, permanent and complete flooding where it will not, and such flooding is possible; proper paving of unhealthy towns, and the filling-in of stagnant, swampy pools; these--in other words, all measures calculated to keep down mosquitoes--are the more important things to be striven for in attempting the sanitation of malarious districts. In England, in Holland, in France, in Algeria, in America, and in many other places, enormous tracts of country, which formerly were useless and pestilential, have been rendered healthy and productive by such means." (Manson.) And, short of such great enterprises as Government works of drainage, much has already been done, in many African towns, and in India, by the work of a few men and women: not only by practical sanitary improvements, but by insistent teaching and lecturing. For the admirable results recently obtained in Ismailia, Algeria, Formosa, and the Malay States, see the _Medical Annual_, 1905 and 1906.[39] [39] This paper, by Dr. Stephens, gives also the reasons why equally good results were not obtained at Mian Mir, Punjab. The whole paper is of great interest. Before leaving the subject of malaria, it must be added that the discovery and study of the parasite which causes it have cleared up the mystery of the specific action of quinine upon the disease. It operates simply by its germicidal effect upon the microbe. But, beyond this, we have now a clue which we never had before to guide us to the most advantageous manner of administering the drug. 2. YELLOW FEVER The specific organism of malaria may become active again and again in the blood, causing relapses twenty years or more after the original infection. The specific organism of yellow fever expends itself at once, in one acute attack; and, if the patient recovers, he is thenceforth more or less immune against infection. That the inoculation of the disease, by the application of a single mosquito recently contaminated, is calculated to produce a mild or abortive attack less dangerous than the average attack among the non-acclimatised, was known to Finlay, and was confirmed in 1899 by the Army Commission of the United States. Of the mortality of the disease, Sir Patrick Manson, in 1900, wrote as follows:-- "It is better for women and children than for men; better for old residents than for newcomers; worst of all for the intemperate. According to a table of 293 carefully observed cases given by Sternberg, the mean mortality in the whole 293 cases was 27.7 per cent. This may be taken as a fairly representative mortality in yellow fever among the unacclimatised, something between 25 and 30 per cent., although in some epidemics it has risen as high as 50 or even 80 per cent. of those attacked.... Some of these epidemic visitations bring a heavy death-bill; thus, in New Orleans, in 1853, 7970 people died of yellow fever; in 1867, 3093; in Rio, in 1850, it claimed 4160 victims; in 1852, 1943; and in 1886, 1397. In Havana, the annual mortality from this cause ranges from 500 to 1600 or over." The earlier attempts to reproduce the disease, by inoculation with its products, failed altogether:-- "In 1816, Dr. Chervin, of Point-à-Pitre (Antilles), drank repeatedly large quantities of black vomit without feeling the least disturbance. Some years before, other North American colleagues, Doctors Potter, Firth, Catteral, and Parker, did everything possible to inoculate themselves with yellow fever. After having uselessly attempted experiments on animals, they experimented on themselves, inoculating the black matter at the very moment in which the moribund patient rejected it, placing this matter in their eyes, or in wounds made in their arms, injecting it more than twenty times in various parts of their body ... in short, devising every sort of daring means for experimentally transmitting yellow fever. All these experiments were without result, and in the United States during many years it was believed that this terrible malady was non-contagious." (_British Medical Journal_, 3rd July, 1897.) The history of the subject, from 1812 to 1880, is given by Dr. Finlay of Havana, in the _New York Medical Record_ (9th February 1901). In 1880, two very important reports on the disease were published; one by a Havana Commission of the National Board of Health of the United States, the other by the United States Navy Department. They tended to show that yellow fever is a "germ-disease"; that it is not wind-borne; and that there may be some change, outside the body of the patient, whereby the virulence of the active principle of the disease is heightened. From these reports, Dr. Finlay advanced his doctrine that the mosquito receives and transmits the germs of the disease:-- "It was upon the above line of reasoning (in these reports), that I conceived the idea that the yellow-fever germ must be conveyed from the patient to the non-immunes by inoculation, a process which could be performed in nature only through the agency of some stinging insect whose biological conditions must be identical with those which were known to favour the transmissibility of the disease." In 1881 he inoculated himself and six soldiers with infected mosquitoes, and obtained, as he had calculated, mild attacks and subsequent immunity. During the years 1881-1900 he inoculated by this method 104 persons:-- "In these inoculations, be it remembered, my principal object was rather to avoid than to seek the development of a severe attack; in point of fact, only seventeen showed any appreciable pathogenic effects after their inoculation. I felt sure, however, that severe or fatal result might follow an inoculation either with several mosquitoes contaminated from severe cases of the disease, or from a single insect applied several days or weeks after its contamination, having come to this last conclusion in view of the facts connected with the _Anne Marie_, and the epidemic of Saint Nazaire." Dr. Finlay's discovery that the mosquito can convey yellow fever, and that the germ of the disease is more virulent after a prolonged sojourning in the mosquito, was proved beyond all question by the work of 1889-1901. But, so far as immunisation is concerned, few people would submit themselves to be bitten by an infected mosquito, even with perfect assurance that the germs contained in it were of a low degree of virulence: the urgent need, therefore, was for an immunising serum. In 1896, at Flores, Sanarelli discovered the _bacillus icteroides_; and by October 1897, he had prepared an immunising serum which was able to give a considerable amount of protection to animals.[40] Next year (_Annales de l'Institut Pasteur_, May 1898) came the news that he had advanced against yellow fever with its own weapons--_Premières expériences sur l'emploi du sérum curatif et préventif de la fièvre jaune_. Of the first 8 cases (Rio de Janeiro), 4 recovered. Then came the 22 cases at San Carlos do Pinhal, in Saint-Paul au Brésil (January 1898), with 16 recoveries, and only 6 deaths. And it is to be noted that he submitted his method of treatment to the utmost test that was possible; he chose the bad cases, and the country where the fever was most fatal:-- "Chaque cas était choisi de commun accord entre nous, dans le but de mettre bien en évidence l'action thérapeutique du sérum, _mettant toujours de côté tous les cas qui se présentaient avec des symptômes vagues ou attenuès ou en forme légère ou fruste. On ne conservait donc que des cas oû, d'après la violence des phénomènes d'invasion, on devait considérer comme très peu probable une crise spontanée de la maladie_...." [40] It is not denied here that he made five experiments on human beings. See Part IV. chap. ii. Furthermore, Sanarelli was able to show the preventive value of the serum. At the end of February 1898, yellow fever broke out in the jail at San Carlos:-- "La première victime fut un condamné, qui vivait avec tous les autres dans une salle oû les conditions hygiéniques étaient assez mauvaises. Le lendemain, la sentinelle, qui était en rapport continuel avec la salle des condamnés, tombait malade. Quelques jours après, un autre condamné suivait le sort du premier, et bientôt un quatrième cas, mortel aussi, finit par signaler la prison comme un nouveau foyer d'infection qui venait s'allumer au centre d'un quartier de la ville encore resté indemne. "Si on avait abandonné la chose à elle-même, on aurait vu se produire le même spectacle qu'avaient fourni, dans les conditions identiques, pendant les dernières épidémies, les prisons de Rio-Claro, de Limeira, et d'autres villes de l'État de Saint-Paul." Every prisoner, except one who had already had the fever, was therefore given the preventive treatment. At once the outbreak stopped; no more cases occurred, though only a weak serum was used, though the state of the prison and its occupants was unhealthy, though the fever, two months later, was still raging round the prison, in the town. In October 1900, the United States Commission on Yellow Fever published a preliminary report on 11 cases of mosquito-inoculation. Of these, the majority gave a negative result, and were found susceptible to infection, at a later date, from the blood of a yellow-fever patient. Two gave a positive result. In the course of these experiments, Dr. Lazear, a member of the Commission, died of the disease. In February 1901, and again in July, the Commission published further reports, emphasising the fact that the mosquito conveys the disease, and denying that the disease can be conveyed in clothing, bedding, and so forth:-- "Our observations appear to demonstrate that the parasite of this disease must undergo a definite cycle of development in the body of the mosquito before the latter is capable of conveying infection. This period would seem to be not less than twelve days. "We also consider the question of house infection, and are able to show that this infection is due to the presence of mosquitoes that have previously bitten yellow-fever patients; and that the danger of contracting the disease may be avoided in the case of non-immune individuals who sleep in this building, by the use of a wire screen. "We also demonstrate, by observations made at this camp (Fort Lazear), that clothes and bedding contaminated by contact with yellow-fever cases, or by the excreta of these cases, is absolutely without effect in conveying the disease." In February 1901, Dr. H. E. Durham published an abstract of an _interim_ report of the Liverpool School Yellow Fever Commission. He and Dr. Walter Myers, the two Commissioners, had both of them been attacked by the disease, and Dr. Myers had died of it. The report gives evidence that the disease is due to a bacillus which is not the _bacillus icteroides_; and it does not wholly favour the earlier report (1900) of the American Commission. A later Commission to New Orleans, September 1901 to January 1902, reported an extensive series of investigations, which seem rather to support the belief that the _bacillus icteroides_ is the cause of the disease. Later still, this belief is again denied; and, as in rabies, so in yellow fever, the good work has gone on without waiting for the identity of this or that micro-organism. * * * * * Immunisation, by the direct use of an infected mosquito, may be compared with the old custom of inoculation against smallpox. The use of Sanarelli's serum-treatment has not gone far. There remains for consideration the method of keeping down infection by keeping down _Culex_. Three reports, in 1901-1902, come from Dr. Guitéras (Havana), Surgeon-Major Gorgas, chief sanitary officer (Havana), and the Commission at New Orleans. Dr. Guitéras reports that 6 cases of yellow fever (inoculation) were treated in a large "mosquito-proof" building, which also contained cases of other diseases. No prophylaxis was enforced, save the exclusion of mosquitoes; non-immunes visited the yellow fever cases, non-immunes nursed them, and most of the attendants and labourers about the place were non-immunes; but not a single case of infection occurred. The New Orleans Commission reports that, of 200 cisterns, &c., examined in the city for the presence of larvæ, the larva of _Culex_ (_Stegomyia_) predominated in more than 60 per cent. The report of Surgeon-Major Gorgas is very pleasant reading. For two centuries, Cuba had been cursed with yellow fever; then, after the war with Spain, America took it over:-- "The army took charge of the health department of Havana, when deaths (from all causes) were occurring at the rate of 21,252 per year. It gives it up, with deaths occurring at the rate of 5720 per year. It took charge, with smallpox endemic for years. It gives it up, with not a case having occurred in the city for over eighteen months. It took charge, with yellow fever endemic for two centuries--the relentless foe of every foreigner who came within Havana's borders, which he could not escape, and from whose attack he well knew every fourth man must die. The army has stamped out this disease in its greatest stronghold." Make fair allowance for the wide variation, from year to year, of the number of yellow fever cases in any town within the geographical belt of the disease; admit that a town may, in the course of nature, have many hundred cases in one year, and only half a dozen in another year. Again, make fair allowance for all other good influences of the American occupation of Cuba, beside those that were concerned with the stamping out of _Culex_; admit that the general death-rate of Havana, in the last February of Spanish rule (1898), was 82.32 per thousand, and in February 1901, was 19.32. Still, there is an example here, in the 1901 work in Havana, for the world to follow, wherever yellow fever exists. The following abstract of Surgeon-Major Gorgas' results was published in the _Practitioner_, May 1902, by Professor Hewlett, one of the foremost of English bacteriologists:-- "Commencing in February 1901, orders were issued that every suspected case of yellow fever should be screened with wire gauze at the public expense, so as to render the room or rooms mosquito-proof. All mosquitoes in the infected house and in contiguous houses were destroyed. After the middle of February, 100 men were employed in carrying out the destruction of the mosquito-larvæ in their breeding places, putting oil in the cesspools of all houses, clearing the streams, draining pools, and oiling the larger bodies of water. Up to June, quarantine was enforced, together with disinfection of the house and fomites. After that, however, rigid quarantine of the patient was stopped, and disinfection of fabrics and clothing ceased. It was merely required that the patient should be reported, his house placarded and screened, and a guard placed over each case to report how general sick-room sanitation was carried out, to see that the screen-door communicating with the screened part of the house was kept properly closed, and to see that communication with the sick-room was not too free, four or five non-immunes only being allowed in. _By the end of September, the last focus of the disease had been got rid of, and since then, up to the beginning of January, there has not been a single case._ Whereas, for the years since 1889, from 1st April to 1st December, yellow fever caused an average of 410.54 deaths, with a maximum of 1175 for 1896, and a minimum of 79 for 1899, _it caused in 1901 5 deaths only. In the months of October and November, when the disease has hitherto been exceedingly rife in Havana, there has not been a single case. For the first time in 150 years, Havana has been free from yellow fever._" Sir Patrick Manson, lecturing in America, last year, on tropical diseases, summed up the work as follows:-- "Time will not permit--what to you is probably quite unnecessary--the recapitulation of the story of the labours of Reed and his coadjutors. I cannot pass on, however, to what I have to say in connection with this work without a word of admiration for the insight, the energy, the skill, the courage, and withal the modesty and simplicity of the leader of that remarkable band of workers. If any man deserved a monument to his memory, it was Reed. If any band of men deserve recognition at the hands of their countrymen, it is Reed's colleagues. "The principal outcome of the labours of these men has been the demonstration, first, that the ultra-microscopic germ of yellow fever is present in the blood of the patient during the first three days of the disease. Second, that the first step in the passage of the germ from the sick to the sound is made, under natural conditions, in the stegomyia mosquito. And third, that after about twelve days and upwards in stegomyia, the yellow fever germ, when implanted by the said mosquito into another human host, is capable of reproduction, so that at the end of a further period of about three days it has established itself throughout the blood, is causing the violent reaction, the clinical manifestations of which we call yellow fever, and is once more in a condition to re-enter the mosquito. "These are great etiological facts. They are of supreme practical and scientific value. Acting on them, the United States sanitary authorities expelled yellow fever from Havana. Acting on them, they should be able in the future to protect the United States themselves from such terrible visitations as in the past have swept through some of your cities." 3. FILARIASIS These same lectures contain an admirable account of the life-history of _Filaria_. It is not necessary here to describe the loathsome deformities which occur in the later stages of filariasis. These deformities (_elephantiasis_, Barbadoes leg), which may attain colossal size, are due to the blocking of the lymphatic vessels with filarial worms. Cases of the disease are hardly ever seen in this country; but it is very frequent in some parts of the tropics. _In the endemic areas_, says Manson, _10 per cent. is not an uncommon proportion of the population to be found affected with filariasis. Thirty and even 50 per cent. may be affected. In many of the Pacific Islands--the Samoa group for instance--I believe that even this proportion is exceeded._ That _Culex_ (_fatigans_) can carry the parasite, has been proved past all doubt. Neither does anybody doubt, that the keeping down of this mosquito would keep down filariasis. A report of great interest, from Barbadoes, was published in the _British Medical Journal_ for 14th June 1902. It is written by Dr. Low, whose experiment on himself in the Campagna has already been noted in this chapter. Dr. Low reports that there is no indigenous malaria in the island, and that neither he nor Mr. Lefroy could find a single _Anopheles_ larva, though they hunted diligently in the swamps and other likely places. But filariasis is terribly common, and so is _Culex fatigans_. Dr. Low examined the night-blood of 600 cases of all kinds in the General Hospital, the Central Almshouse, and elsewhere, and found the filaria-embryos in no less than 76 = 12.66 per cent. He caught and dissected a hundred mosquitoes (_Culex fatigans_) from the wards and corridors of the General Hospital, and found that no less than 23 of them were infected. If it were not for _Culex_, and for men's indifference and apathy, filariasis could be kept down all over the island:-- "There is a perfect water supply, and people can get their water fresh from the standpipes at their doors. Old wells ought to be filled up; no water-barrels or tubs should be allowed, or, if kept, they should be emptied every week or so. Tanks and collections of water in gardens should all be periodically treated with kerosene, or be furnished with closely-fitting covers to prevent mosquitoes getting in. These methods are simple and inexpensive, and each householder should see that they are applied in his garden and grounds. The difficulty begins when one has to take into account the inability of the negro to grasp anything of a hygienic nature. The only way to get over this, would be a system of sanitary inspection by a few competent men. For individual prophylaxis, mosquito-nets ought always to be used; but many, even educated people, still persist in sleeping without them; of course, nothing in this line can be expected of the native population. "If such means were adopted for Barbadoes, the presence of filarial disease, which at present is quite alarming, could easily, with little trouble and expense, be greatly diminished, and thus save much suffering, as well as loss of time, hideous deformity, and doubtless in not a few instances loss of life." Thus, in a few years, from experiments on mosquitoes, sparrows, and men, has come the present plan of campaign against malaria, yellow fever, and filariasis; that is, against _Anopheles_ and _Culex_. He who would know what is being done to check these diseases in Italy, India, China, Africa, and America, must read Prof. Ross' _Malarial Fever, its Cause, Prevention, and Treatment_ (1902), and _Mosquito Brigades, and how to organise them_ (1902). There has been nothing like it since Pasteur died. Far and wide, from Staten Island to Cuba, from Hong Kong to Lagos, the work of keeping down the larvæ of _Anopheles_ and _Culex_ is going on. _Henceforth we have to reckon not with a nameless something, but with a definite parasite, whose conditions of life are known. Before all things, we must shut off the sources of the infection._ For centuries, men had believed in exhalations and miasmata lying all over the land: and, behold, the agents of malaria are in the puddles round a man's house, and the agents of yellow fever are in the water-butt and the broken bottles and old sardine-tins. Science has given the word, and now there are _Anopheles_ brigades and _Culex_ brigades set going; labourers with brooms and rubbish-carts, sweeping out the stagnant pools, draining the surface soil, and carrying off the odd receptacles that serve to hold mosquito eggs and larvæ. The job, like all sanitary jobs, must be steady, year in, year out: it must be limited to infected places, a whole continent cannot be treated. But there the work is, and will grow; and saves, by unskilled labour, and at a trivial expense, those "non-acclimatised" lives that have hitherto been thrown away as recklessly as the larvæ that are now swept out of the puddles and ditches round African settlements. XI PARASITIC DISEASES The foregoing chapters are concerned with bacteriology alone, and with those curative or preventive methods of treatment that have come out of inoculation-experiments on animals. The lives that are saved, or safeguarded, by these methods, even in one year, must be many thousands in each country of the civilised world. And, beside human lives, there is the protection of sheep and cattle against anthrax, swine against rouget, horses against tetanus, cattle against rinderpest. In Cape Colony alone, so far back as 1899, about half a million cattle had received preventive treatment against rinderpest; and the sum total of human and animal lives saved or safeguarded, in all parts of the world, must be reckoned in millions by this time. The present chapter, and the next two chapters, are concerned with methods that have come out of experiments on animals, but not out of bacteriology. It is plain that the grosser parasites of the human body, tapeworms and the like, could not be explained or understood without the help of feeding-experiments on animals. By this method, and by this alone, their life-history was discovered. They were known to Aristotle and to Hippocrates; but nothing was understood about them. They were never studied, for this among other reasons, that men believed in spontaneous generation; and the presence of lower forms of life inside human bodies was attributed to the fault of the patient, or the work of the devil. Then, at last, Redi (1712), and Swammerdam (1752) in his _Bibel der Natur_, struck at the doctrine of spontaneous generation, saying that it did not apply to insects; and in 1781 Pallas boldly declared that the internal parasites of man came out of eggs, like insects, and not "of themselves." It would be a good theme for an essay--_The paralysing effect, on medicine and surgery, of the doctrine of spontaneous generation_. Rudolphi (1808) and Bremser (1819) opposed Pallas; and von Siebold (1835) and Eschricht (1837) supported him. Then came the great students of this part of biology--Cobbold, Busk, Davaine, van Beneden, Leuckart, Küchenmeister. In 1842, Steenstrup had discovered, in certain insects, the alternation of generations; in 1852, Küchenmeister proved that the generations of internal parasites are similarly alternate. By feeding carnivorous animals with "measly" meat, he produced tapeworms in them; and by feeding herbivorous animals with the ova of tapeworms, he made their muscles "measly." The feeding of animals was the only possible way to understand the bewildering transformations and transmigrations of the thirty or more entozoa to which flesh is heir. This chapter of pathology makes up in tragedy what it lacks in romance; for these animal parasites have killed whole hosts of people. Take, for instance, the _trichina spiralis_, a minute worm discovered in 1835 encysted in countless numbers in the muscles of the human body; it was studied by Virchow, Leuckart, and others, by feeding-experiments on animals, and was proved to come from infected half-cooked ham and pork, and to make its way from the alimentary canal all over the body. The name of trichiniasis or trichina-fever was given to the acute illness that came of the sudden dissemination of these myriad parasites into the tissues. Trichiniasis had killed hundreds of people by a most painful death; outbreaks of it, in Germany and elsewhere, had swept through villages like cholera or plague: then Leuckart and Virchow traced it to its source, and it was stopped there--_Above all things, we must shut off the sources of the infection_--the butchers' shops were kept under sanitary inspection, people were warned against half-cooked ham and pork, and there was an end of it. Or take hydatid disease, which occurs in all parts of the world, and in some countries (Australia, Iceland) is terribly common. The nature of this disease--that it is an animal parasite transmissible between men and dogs--was proved by feeding-experiments on animals. In Iceland, where men and dogs live crowded together in huts, there is an appalling number of deaths from hydatid disease; Leuckart, in 1863, of it:-- "At present, almost the sixth part of all the inhabitants annually dying in Iceland fall victims to the echinococcus epidemic." Before Küchenmeister's experiments in 1852, there was no general knowledge of the exact pathology of entozoic disease. The advance was not made by the experimental method alone; other things helped: but among them was neither clinical experience, nor what Sir Charles Bell called "the observation of the just facts of anatomy and of natural motions." * * * * * Beside the entozoa, there are also vegetable parasites. Of these, the most important is the _streptothrix actinomyces_, the cause of actinomycosis in man and cattle. Israel, in 1877, gave the first accurate account of it in man; and Böllinger, the same year, studied it in cattle. Ponfick, in 1882, recognised the identity of the disease in man and animals. In 1885, Israel published the collected records of 37 cases in man, tabulated according to the site of the primary infection. Boström, about this time, made cultures of the fungus: but all the earlier attempts at inoculation failed; and it was not till 1891 that Wolff and Israel published their successful inoculations, and thus completed the evidence that actinomycosis is a parasitic infection, a growth of vegetable threads and spores, transmissible between men and animals, and able to keep its vitality outside its host; so that men who are employed with cattle, or have the habit of chewing straws or ears of corn, incur some slight risk of infection. Before 1877, the disease was hardly suspected in man, and was not understood in cattle. XII MYXOEDEMA On 4th October 1873, Sir William Gull read a short paper before the Clinical Society of London, "On a Cretinoid State supervening in Adult Life in Women." This famous first account of myxoedema was based on five cases: it is less than five pages long, it does not suggest a name for the disease, and it says nothing about the thyroid gland. Four years later (23rd October 1877), Dr. Ord read a paper before the Medico-Chirurgical Society of London, "On Myxoedema; a term proposed to be applied to an essential condition in the 'Cretinoid' Affection occasionally observed in Middle-aged Women." His work had begun so far back as 1861; and in this 1877 paper he gave not only clinical observations, but also pathological and chemical facts; and he noted, as one among many changes, wasting of the thyroid gland. He also pointed out the close resemblance between cases of myxoedema and cases of sporadic cretinism. In 1882, Reverdin stated before the Medical Society of Geneva that signs like those of myxoedema had been observed in some cases of removal of the thyroid gland on account of disease (goître). In April 1883, Kocher of Berne read a paper on this subject, before the Congress of German Surgeons; but he attributed this myxoedema after removal of the gland (cachexia strumipriva) not directly to the loss of thyroid-tissue, but rather to some sort of interference with free respiration, due to operation. On 23rd November, Sir Felix Semon brought the subject again before the Clinical Society; and on 14th December 1883, the Society appointed a Committee of Investigation to study the whole question. Their report, 215 pages long, with tabulated records of 119 cases of myxoedema, was published in 1888. It is a monument of good work, historical, clinical, pathological, chemical, and experimental. Twenty years ago, the purpose of the thyroid gland was unknown: a few experiments had been made on it, by Sir Astley Cooper and others, and had failed; and Claude Bernard, in his _Physiologie Opératoire_ (published in 1879, soon after his death), makes it clear that nothing was known in his time about it. He is emphasising the fact that anatomy cannot make the discoveries of physiology:-- "The descriptive anatomy, and the microscopic characters, of the thyroid gland, the facts about its blood-vessels and its lymphatics--are not all these as well known in the thyroid gland as in other organs? Is not the same thing true of the thymus gland, and the suprarenal capsules? _Yet we know absolutely nothing about the functions of these organs--we have not so much as an idea what use and importance they may possess--because experiments have told us nothing about them_; and anatomy, left to itself, is absolutely silent on the subject." Therefore, in 1882-83, things stood at this point--that the removal of a diseased thyroid gland had been followed, in some cases, by a train of symptoms such as Sir William Gull had recorded in 1873. Would the same symptoms follow removal of the healthy gland? The answer was given by Sir Victor Horsley's experiments, begun in 1884. He was able, by removal of the gland, to produce in monkeys a chronic myxoedema, a cretinoid state, the facsimile of the disease in man: the same symptoms, course, tissue-changes, the same physical and mental hebetude, the same alterations of the excretions, the temperature, and the voice. It was now past doubt that myxoedema was due to want of thyroid-tissue, and to that alone; and that "cachexia strumipriva" was due to the loss, by operation, of such remnants of the gland as had not been rendered useless by disease. The advance had still to be made from pathology to treatment. Here, so far as England is concerned, honour is again due to Sir Victor Horsley. On 8th February 1890, he published the suggestion that thyroid-tissue, from an animal just killed, should be transplanted beneath the skin of a myxoedematous patient:-- "The justification of this procedure rested on the remarkable experiments of Schiff and von Eisselsberg. I only became aware in April 1890, that this proposal had been in fact forestalled in 1889 by Dr. Bircher, in Aarau. (The date of Dr. Bircher's operation was 16th January 1889.) Kocher had tried to do the same thing in 1883, but the graft was soon absorbed; but early in 1889 he tried it again, in five cases, and one greatly improved." The importance of this treatment, by transplantation of living thyroid-tissue, must be judged by the fact that in 1888 no practical use had yet been made of the scientific work that had been done. The Clinical Society's Report, published that year, gives but half a page to treatment, of the old-fashioned sort; and not a word of hope. Then, at last, in 1891, came Dr. George Murray's paper in the _British Medical Journal_, "Note on the Treatment of Myxoedema by Hypodermic Injections of an Extract of the Thyroid Gland of a Sheep." Later, hypodermic injections of thyroid-extract gave way to sandwiches, made with thyroid gland (Dr. Hector Mackenzie, and Dr. Fox of Plymouth), and these in their turn were eclipsed by tabloids. It is a strange sequence, from 1873 onward: clinical observation, _post-mortem_ work, calamities of surgery, experimental physiology, transplantation, hypodermic injections, sandwiches, and tabloids. And far more has been achieved than the cure of myxoedema. Even if the discovery stopped here, it would still be a miracle that little bottles of tabloids should bring men and women back from myxoedema to what they were before they became thick-witted, slow, changed almost past recognition, drifting toward idiocy. But it does not stop here. The same treatment has given good results in countless cases of sporadic cretinism, restoring growth of body and of mind to children that were hopelessly imbecile. It is of great value also for certain diseases of the skin. Moreover, physiology has gained knowledge of the purpose of the thyroid gland, and a clearer insight into the facts relating to internal secretion. XIII THE ACTION OF DRUGS Long after the Renaissance, the practice of medicine was still under the influence of magic. Whatever things were rare and precious were held to be good against disease--gold, amber, coral, pearls, and the dust of mummies; whatever took strange forms of life--toads, earthworms, and the like; whatever looked like the disease, after the doctrine of signatures--pulmonaria for the lungs, because the spots on its leaves were like tubercle, a kidney-shaped fruit for the kidneys, a heart-shaped fruit for the heart, and yellow carrots for the yellow jaundice. Among the drugs in the 1618 Pharmacopoeia are _cranium humanum_, _mandibula lucii_, _nidus hirundinum_, _sericum crudum_, _linum vivum_, and _pilus salamandræ_. In the Pharmacopoeia of 1667 are _exuviæ serpentis_, _telæ aranearum_, _saliva jejuni_, _cranium hominis violentâ morte extincti_, and worse obscenities. Soon after the publication of this Pharmacopoeia, on 14th February 1685, King Charles II. died; and in the Library of the Society of Antiquaries there is a manuscript account in Latin, by Dr. Scarbrugh, how the case was treated. The King had sixteen physicians, and nine consultations in five days; and to say "everything was done that was possible" gives no idea of the vigour of the treatment. Finally, the day he died, they gave him, eleven of them in consultation--_totus medicorum chorus ab omni spe destitutus_--they gave him, as _more generous cardiacs_, the _lapis Goæ_, and the _Bezoar-stone_. The _lapis Goæ_ was a dust of topaz, jacinth, sapphire, ruby, pearl, emerald, bezoar, coral, musk, ambergris, and gold, all made into a pill and polished; and the _bezoar_ is a calculus found in the intestines of herbivorous animals. Half a century later, the Pharmacopoeia of 1721 still included ants' eggs, teeth, _lapis nephriticus_, and other horrors; and in the Pharmacopoeia of 1746, though the dust of Egyptian mummies was ruled out, vipers and wood-lice were retained. Certainly these "last enchantments of the Middle Ages" were slow to depart. Clinical observation, anatomy, and pathology, had all failed to bring about a right understanding of the actions of drugs. It was the physiologists, not the doctors, who first formulated the exact use of drugs; it was Bichat, Magendie, and Claude Bernard. That is the whole meaning of Magendie's work on the upas-poison and on strychnine, and Claude Bernard's work on curari and digitalis. Of these four substances, two only are of any use in practice; yet Magendie's study of strychnine[41] was of immeasurable value, not so much because it gave the doctors a "more generous cardiac," though that was a great gift, but because it revealed the _selective_ action of drugs. Contrast his account of strychnine with Ambroise Paré's story how they tested the bezoar-stone on the thief instead of hanging him; contrast Bernard's chapter on curari with Dr. Scarbrugh's notes on the King's death, with all the Crown jewels inside him: you are in two different worlds. The _selective_ action of drugs--the affinity between strychnine and the central nerve-cells, between curari and the terminal filaments of the motor nerves--that was the revolutionary teaching of science: and it came, not by experience, but by experiment. [41] For a full statement of the great value of this study of strychnine, see Cl. Bernard, _Leçons de Physiologie Opératoire_, 1879, p. 89. Take Professor Fraser's address on "The Action of Remedies, and the Experimental Method" at the International Medical Congress in London, 1881:-- "The introduction of this method is due to Bichat; and, by its subsequent application by Magendie, pharmacology was originated as the science we now recognise. Bichat represents a transition state, in which metaphysical conceptions were mingled with the results of experience. Magendie more clearly recognised the danger of adopting theories, in the existing imperfections of knowledge; and devoted himself to the supplementing of these imperfections by experiments on living animals. The advantages of such experiments he early illustrated by his investigation on the upas-poison; and afterwards by a research on the then newly-discovered alkaloid, strychnia.... He demonstrated the action of this substance upon the spinal cord, by experiments upon the lower animals, so thoroughly, that subsequent investigations have added but little to his results." Or take Professor Fraser's account of digitalis:-- "It was introduced as a remedy for dropsy; and, on the applications which were made of it for the treatment of that disease, a slowing action upon the cardiac movements was observed, which led to its acquiring the reputation of a cardiac sedative. Numerous observations were made on man by the originators of its application, by Dr. Sanders and many other physicians, in which special attention was paid to its effects upon the circulation; but no further light was thrown upon its remarkable properties, with the unimportant exception that in some cases it was found to excite the circulation. It was not until the experimental method was applied in its investigation, in the first instance by Claude Bernard, and subsequently by Dybkowsky, Pelikan, Meyer, Boehm, and Schmiedeberg, that the true action of digitalis upon the circulation was discovered. It was shown that the effects upon the circulation were not in any exact sense sedative, but, on the contrary, stimulant and tonic, rendering the action of the heart more powerful, and increasing the tension in the blood-vessels. The indications for its use in disease were thereby revolutionised, and at the same time rendered more exact; and the striking benefits which are now afforded by the use of this substance in most (cardiac) diseases were made available to humanity." Or take Sir T. Lauder Brunton's account of the action of nitrite of amyl in angina pectoris:-- "The action of nitrite of amyl in causing flushing was first observed by Guthrie, and Sir B. W. Richardson recommended it as a remedy in spasmodic conditions, from the power he thought it to possess of paralysing motor nerves. In the spring of 1867 I had opportunities of constantly observing a patient who suffered from angina pectoris, and of obtaining from him numerous sphygmographic tracings, both during the attack and during the interval. These showed that during the attack the pulse became quicker, the blood-pressure rose, and the arterioles contracted.... It seemed probable that the great rise in tension was the cause of the pain, and it occurred to me that if it was possible to diminish the tension by drugs instead of by bleeding, the pain would be removed. "I knew from unpublished experiments on animals by Dr. A. Gamgee that nitrite of amyl had this power, and therefore tried it on the patient. My expectations were perfectly answered. The pain usually disappeared in three-quarters of a minute after the inhalation began, and at the same time the pulse became slower and much fuller, and the tension diminished." Of course it would be easy to lengthen out the list. Aconite, adrenalin, belladonna, calcium chloride, colchicum, cocain, chloral, ergot, morphia, salicylic acid, strophanthus, the chief diuretics, the chief diaphoretics--all these drugs, and many more, have been studied and learned by experiments on animals. Then comes the answer, that drugs act differently on animals and on men. The few instances, that give a wise air to this foolish answer, were known long ago to everybody: they do not so much as touch the facts of daily practice:-- "The action of drugs on man differs from that on the lower animals chiefly in respect to the brain, which is so much more greatly developed in man. Where the structure of an organ or tissue is nearly the same in man and in the lower animals, the action of drugs upon it is similar. Thus we find that carbonic oxide, and nitrites, produce similar changes in the blood of frogs, dogs, and man, that curare paralyses the motor nerves, alike in them all, and veratria exerts upon the muscles of each its peculiar stimulant and paralysing action. Where differences exist in the structure of the various organs, we find, as we would naturally expect, differences in their reaction to drugs. Thus the heart of the frog is simpler than that of dogs or men, and less affected by the central nervous system; we consequently find that while such a drug as digitalis has a somewhat similar action upon the hearts of frogs, dogs, and men, there are certain differences between its effect upon the heart of a frog and on that of mammals. "Belladonna offers another example of apparent difference in action--a considerable dose of belladonna will produce almost no apparent effect upon a rabbit, while a smaller dose in a dog or a man would cause the rapidity of the pulse to be nearly doubled. Yet in all three--rabbits, dogs, and men--belladonna paralyses the power of the vagus over the heart. The difference is that in rabbits the vagus normally exerts but little action on the heart, and the effect of its paralysis is consequently slight or hardly appreciable." (Professor Fraser.) It would be strange indeed, if experts who work in micromillimetres and decimal milligrammes, and study the vanishing-point of microscopic structures, and measure and ordain infinitesimal changes in invisible organisms, were blind to such gross and palpable differences as exist between men and pigeons in their susceptibility to a dose of opium. Anæsthetics must be reckoned among the drugs that have been studied on animals: but, for the discovery of them, men experimented on themselves. The first use of nitrous oxide (laughing gas) in surgery was 11th December 1844, when Horace Wells, of Connecticut, had it administered to himself for the removal of a tooth. The first use of ether was made by Dr. Long, of Athens, Georgia; but he did not publish the case, or follow up the work: and the honour of the discovery of ether went to Morton, of Boston, who made repeated experiments, both on animals and on himself. The date when he first rendered himself absolutely unconscious for seven or eight minutes, is 30th September 1846; and the first operation under ether was done on 16th October, in the Massachusetts General Hospital. The first use of chloroform was 4th November 1847, that famous evening when Simpson, George Keith, and Matthews Duncan took it together. The whole history of anæsthesia is to be found in the _Practitioner_, Oct. 1896. It is sometimes said that the men who make experiments on animals ought to make them on themselves. But they do, hundreds of them, and suffer for it: Heaven knows the list is long enough--the discoverers of anæsthesia, Hunter, Garré, Koch, Klein, Moor, Haffkine, Grassi, Bochefontaine, Quesada, Sanarelli, Pettenkofer--these and hosts more, here or abroad, have done it, as part of the day's work; and some--by accidental infection, like Chabry and Villa, or by deliberate self-inoculation, like Carrion--have been killed:-- "Dr. Angelo Knorr, _Privat-docent_ in the Veterinary School of Munich, died on 22nd February from acute glanders, contracted in the course of an experimental research on mallein. Helmann, the Russian investigator who discovered mallein, himself fell a victim to accidental inoculation of the glanders virus. Some time afterwards another Russian, Protopopow, died of glanders contracted in a French laboratory. An Austrian physician, Dr. Koffman-Wellenhof, died of the same disease, contracted in the Institute of Hygiene at Vienna. On 17th January of the present year Dr. Guiseppe Bosso, of the University of Turin, died of infection contracted in the course of cultivations of tubercle-bacilli made in his laboratory. Not long before, Dr Lola, assistant in the maternity department of the Czech University Hospital of Prague, died of tetanus caused by an experimental inoculation made on himself. Some fourteen or fifteen years ago, a medical student of Lima proved that 'verruga Peruana' is an infectious disease by inoculating himself with it, an act of scientific devotion which cost him his life.[42] Besides those who have died, there are many who have only escaped with their lives after long and painful illness. Professor Kourloff contracted anthrax in a laboratory at Munich, and was saved only by vigorous surgery. Dr. Nicolas supplied, in his own person, the first example of tetanus produced in man by inoculation of the pure toxin of the bacillus of Nicolaier." (_Brit. Med. Journal_, 18th March 1899.) [42] Daniel Carrion, born 1859 at Cerro de Pasco, proved, by self-inoculation, the identity of the two forms of the disease, 27th August 1885; died of the disease, 5th October. See _Ann. de l'Inst. Past._, Sept 1898. This list is seven years old now; it is twice the length by this time. Typhoid, malaria, yellow fever, have all taken toll of those who study them. It is a long record of the men who fell ill, or died, or killed themselves over their work; and the deaths of Barisch, Dr. Müller, and Nurse Pecha, from plague at Vienna (October 1898) are another instance that there is danger in the constant handling of cultures. But these deaths at Vienna were due to the great carelessness of one man. In laboratories in all parts of the world there are stored cultures of all sorts of organisms, yet no harm comes of it. "More cases of infection occur amongst young medical men attending fever cases, whether in private practice or hospital wards, in a single month, than have occurred in the whole of the laboratories in the world since they were established." (_British Medical Journal_, 29th October 1898.) Outside the laboratory, outside the fever hospitals, the risk is something less than a negligible quantity:-- "Apart from plague and cholera, in all the big laboratories studies are uninterruptedly pursued, from one end of the year to the other, upon anthrax, glanders, influenza, Malta fever, various tropical diseases which do not exist at all or are rare in the countries where they are being studied. The laboratories in question are situated in the largest and most important towns of their respective countries; and, within those towns, very often in the most fashionable or most populous centres.... On no occasion was there even a suspicion aroused of an epidemic having been produced by any of the above-mentioned institutes, or by those tens of thousands of operations against cholera performed in India." (Haffkine, _Madras Mail_, 8th December 1898.) XIV SNAKE-VENOM The Report of the 1875 Commission said:-- "It is not possible for us to recommend that the Indian Government should be prohibited from pursuing its endeavours to discover an antidote for snake-bites; or that, without such an effort, your Majesty's Indian subjects should be left to perish in large numbers annually from the effects of these poisons." Certainly it was not possible; and the numbers are large indeed. During 1897, 4227 persons were killed by wild animals in India, and 20,959 by snakes. (_British Medical Journal_, 5th November 1898.) Sir Joseph Fayrer's name must be put in the highest place of all those who have studied the venomous snakes of India. Sewell, in 1887, showed that animals could be rendered immune, by repeated inoculation with minute quantities of rattlesnake-venom, to a dose seven times as large as would kill an unprotected animal. Kanthack, in 1891, immunised animals in the same way against cobra-venom. He also made experiments to ascertain whether the blood-serum of these animals acted as an antidote to the venom. Then came the work of Calmette, Fraser, Phisalix, Bertrand, Martin (Australia), Stephens, and Meyers. Professor Fraser's observations on the antidotal properties of the bile are, of course, of the utmost importance; not only in preventive medicine, but also in physiology. The results obtained by Calmette are a good instance of the fineness and accuracy of the experimental method. It is to be noted that the animals were inoculated with a fine needle, not thrust into cages with snakes, as at zoological gardens; and that an animal thus poisoned has a painless death. The different venoms were measured in decimal milligrammes, and their potency was estimated according to the body-weight of the animal inoculated. As with tetanus, so with snake-venom, there must be a standard, or "unit of toxicity." "The following table gives the relative toxicity, for 1 kilogr. of rabbit, of the different venoms that I have tested. To denote this toxicity I use terms such as Behring, Roux, and Vaillard used for the toxin of tetanus, taking the number of grammes of animal killed by one gramme of toxin:-- 1. Venom of _naja_ 0.25 mgr. per kilogr. of rabbit. One gramme of this venom kills 4000 kilogrammes of rabbit; it has, therefore, an activity of 4,000,000 2. Venom of _hoplocephalus_ 0.29 mgr 3,450,000 3. Venom of _pseudechis_ 1.25 mgr 800,000 4. Venom of _pelias berus_ 4.00 mgr 250,000 "Of course, this estimation of virulence is not absolute; it varies considerably according to the species of animal tested. Thus the guinea-pig, and still more the rat, are extremely sensitive. For instance, 0.15 mgr. of viper-venom is enough to kill, in less than 12 hours, 500 grammes of guinea-pig; so that the activity of this venom with a guinea-pig is 3,333,000, but with a rabbit is not more than 650,000. With more resistant animals, the opposite result is obtained; about 10 mgr. of cobra-venom are necessary to kill a dog of 6.50 kilogrm. weight; but to kill the same weight of rabbit 1.65 mgr. is enough. Thus the virulence of this venom with the rabbit is 4,000,000; but with the dog not more than 650,000." By experiments in test-tubes, Calmette studied these venoms under the influences of heat and various chemical agents. He found how to attenuate their virulence, and how to diminish the local inflammation round the point of inoculation; and it was in the course of these test-tube experiments and inoculations that he discovered the value of calcium hypochlorite as a local application. Working, by various methods, with attenuated venoms, he was able to immunise animals:-- "I have come to immunise rabbits against quantities of venom that are truly colossal. I have got several, vaccinated more than a year ago, which take, without the least discomfort, so much as 40 mgr. of venom of _naja tripudians_ at a single injection; that is to say, enough to kill 80 rabbits of 2 kilogr. weight, or 5 dogs. "Five drops of serum from these rabbits wholly neutralise _in vitro_ (in a glass test-tube) the toxicity of 1 mgr. of _naja_-venom." By 1894 he had found that the serum of an animal, thus immunised by graduated doses of one kind of venom, neutralised other kinds of venom:-- "If 1 mgr. of cobra-venom, or 4 mgr. of viper-venom, be mixed, in a test-tube, with a small quantity of serum from an immunised rabbit, and a fresh rabbit be inoculated with this mixture, it does not suffer any discomfort. It is not even necessary that the serum should come from an animal vaccinated against the same sort of venom as that in the mixture. _The serum of a rabbit immunised against the venom of the cobra or the viper acts indifferently on all the venoms that I have tested._" In 1894 he had prepared enough serum for the treatment to be tried by his own countrymen practising in some of the French colonies. In April 1895, he gave the following account of his work:-- "I have immunised two asses, one having received 220 mgr. of _naja_-venom from 25th September to 31st December 1894, and the other 160 mgr. from 15th October to 31st December. The serum of the first of these two animals has now reached this point, that half a cubic centimetre destroys the toxicity of 1 mgr. of _naja_-venom. Four cubic centimetres of this serum, injected four hours before the inoculation of a dose of venom enough to kill twice over, preserve the animal in every case. It is also therapeutic, under the conditions that I have already defined; that is to say, if you first inoculate a rabbit with such a dose of venom as kills the control-animals in three hours, and then, an hour after injecting the venom, inject under the skin of the abdomen 4 to 5 cubic centimetres of serum, recovery is the rule. When you interfere later than this the results are uncertain; and in all my experiments the delay of an hour and a half is the most that I have been able to reach. "This antivenomous serum of asses has these same antitoxic properties with all kinds of snake-venom; it is equally active _in vitro_, preventive, and therapeutic, with the venoms of _cerastes_, of _trigonocephalus_, of _crotalus_, and of four kinds of Australian snakes that Mr. MacGarvie Smith has sent to M. Roux. I am still injecting these two animals with venom, and I hope to give to their serum at last a much greater antitoxic power." In 1896 four successful cases of this treatment in the human subject were reported in the _British Medical Journal_. In 1898 Calmette made the following statement of his results:-- "It is now nearly two years since the use of my antivenomous serum was introduced in India, in Algeria, in Egypt, on the West Coast of Africa, in America, in the West Indies, Antilles, &c. It has been very often used for men and domestic animals (dogs, horses, oxen), and up to now none of those that have received an injection of serum have succumbed.... A great number of observations have been communicated to me, and not one of them refers to a case of failure." (_British Medical Journal_, 14th May 1898.) Good accounts of Fraser's and Calmette's work are given by Dr. Stone in the _Boston Medical and Surgical Journal_, 7th April 1898, and by Staff-Surgeon Andrews, R.N., in the _British Medical Journal_, 9th September 1899. For other cases see the _Pioneer_, 10th August 1899, the _Lancet_, 25th November 1899, and the _British Medical Journal_, 23rd December 1899. In one of these cases, recorded by Dr. Rennie, the patient was, literally, at the point of death, but recovered after the serum had been injected. Two cases have also been recorded of cobra-bite during work in the laboratory: both of them recovered after injection. "Every Government or private dispensary," says Surgeon Beveridge, "should be supplied with antivenene, which is certainly the best remedy for snake-bite available." The cases are few at present; but it does not appear that the treatment has failed in any case; and, with a new remedy of this kind, it is fairly certain that failures would be published. * * * * * From all these instances in physiology, pathology, bacteriology, and therapeutics, we come to consider the Act relating to experiments on animals in the United Kingdom. Many subjects have been left out; among them, the work of the last few years on the suprarenal glands and adrenalin, and Dr. William Hunter's admirable work on pernicious anæmia. No attempt has been made to describe the researches of experts in many countries into the nature of malignant disease, or to guess what may come of the discovery that mice can be immunised against that form of cancer which occurs in mice and is inoculable from mouse to mouse. Nothing has been said of the discovery that the African sleeping-sickness is due to a blood-parasite carried by flies from man to man. Nothing has been said about those discoveries in bacteriology that have not yet been applied to practice, or of the many inventions of medical and surgical practice that owe only an indirect debt to experiments on animals. Artificial respiration, the transfusion of saline fluid, the hypodermic administration of drugs, the use of oxygen for inhalation, the torsion of arteries, the grafting of skin, the transplantation of bone, the absorbable ligature, the diagnostic and therapeutic uses of electricity, the rational employment of blood-letting--all these good methods have been left out of the list; only some facts have been presented, those that mark most clearly the advance of knowledge and of practice, and stand up even above the rest of the work. There they will stand, when we are all dead and gone: and by them, as by landmarks, all further advance will be guided. PART III THE ACT RELATING TO EXPERIMENTS ON ANIMALS IN GREAT BRITAIN AND IRELAND ACT 39 AND 40 VIC. c. 77 The Royal Commission "On the Practice of subjecting Live Animals to Experiments for Scientific Purposes," was appointed on 22nd June 1875. Its members were--Lord Cardwell (chairman), Lord Winmarleigh, Mr. W. E. Forster, Sir John Karslake, Mr. Huxley, Mr. (Sir John) Erichsen, and Mr. Hutton. Between 5th July and 30th December, 53 witnesses were examined, and 6551 questions were put and answered. The report of the Commission bears date 8th January 1876, and in that year the present Act received the Royal Assent. The evidence before the Commission was all, or nearly all, concerned with physiology, with the work of Magendie, Claude Bernard, and Sir Charles Bell, the action of curare, the _Handbook of the Physiological Laboratory_, the teaching of physiology, and so forth. Very little was said of pathology; and of bacteriology next to nothing. Practically, physiology alone came before the Commissioners; and such experiments in physiology as are now, the youngest of them, more than thirty years old. Bacteriology, at the time of the passing of the Act, had hardly made a beginning. Therefore the Act made no special provision for inoculations, injections, and the whole study of immunisation of animals and men against disease. Experiments of this kind have to be scheduled under one of the existing certificates, to bring them under an Act that was drafted without foreknowledge of them. Certificate A or Certificate B has to be used for this purpose:-- _Certificate A._ "We hereby certify that, in our opinion, insensibility in the animal on which any such experiment may be performed cannot be produced by anæsthetics without necessarily frustrating the object of such experiment." _Certificate B._ "We hereby certify that, in our opinion, the killing of the animal on which any such experiment is performed before it recovers from the influence of the anæsthetic administered to it, would necessarily frustrate the object of such experiment." Under one or other of these certificates must be scheduled all inoculations, injections, feeding-experiments, transplantations of particles of disease, immunisations, and the like. They must be scheduled somehow; and that is the only way of doing it. Where the act of inducing the disease would itself give any pain, if an anæsthetic were not administered--as in the subdural inoculation of a rabbit, or the intra-peritoneal inoculation of an animal with a particle of cancerous tissue--there the licensee must hold, together with the license, Certificate B, because the act of inducing the disease is itself an operation, done under an anæsthetic. If the animal be a dog or a cat, he must hold Certificates B and EE; if it be a horse, ass, or mule, Certificates B and F. Where the act of inducing the disease is not itself painful--as in ordinary inoculation, and in feeding-experiments--the licensee must hold, together with his license, Certificate A, because the animal is not anæsthetised. It is not a painful operation; the experiment consists not in the act of putting the hypodermic needle under the animal's skin, but in the subsequent observation of the course of the disease. Take, for instance, the inoculation of a guinea-pig with tubercle-bacilli: the experiment is the production of tubercle; the experiment lasts till the animal is killed and found to be infected; it is therefore scheduled under Certificate A. Or take the testing, on an animal, of an antitoxin; the experiment is not the injection, but the observation of the result; the animal may not suffer, but the injection must still be done under Certificate A. And, if the animal be a dog or a cat, the licensee must hold Certificates A and E; or, if it be a horse, ass, or mule, Certificates A and F. This want of a special certificate for inoculations is an important matter, because it has led to the belief that painful operations are performed, without anæsthesia, in cases where the only instrument used is a needle. It is hardly reasonable, for instance, that the inoculation of a mouse should be scheduled as a painful operation performed without anæsthesia. The disease, thus painlessly induced, may in many cases be called painless; for instance, snake-venom in the rat, septicæmia in the mouse, malaria in small birds. In other cases, there are such pain and fever as are part of the disease. The form that rabies take in rabbits may fairly be called painless. Inoculations not under the skin, but into the anterior chamber of the eye, are very seldom made; they sound cruel, but cocain renders the surface of the eye wholly insensitive, and the anterior chamber is so far insensitive that a man with blood or pus (_hypopyon_) in the anterior chamber of the eye may suffer no pain from it. A horse or an ass kept for the giving of an antitoxic serum has a more comfortable life than an omnibus horse; and this preparation of the antitoxins, since it is not an experiment, but a direct use of animals in the recognised service of man, does not require a license or certificates under the Act. But the testing of an antitoxin is an experiment, and must be made under a license and Certificate A. It is not the business of this book to consider whether the sensitiveness of a dog, a rabbit, or a guinea-pig can fairly be stated in terms of the physical and mental sensitiveness of men and women. In the world of animals, as in the world of humanity, there are differences of sensitiveness. Anyhow, the pain inflicted on animals may in some cases be measured:-- "A guinea-pig that will rest quietly in your hands before you commence to inject it, will remain perfectly quiet during the introduction of the needle under the skin; and the moment it is returned to the cage it resumes its interrupted feeding. "Arteries, veins, and most of the parts of the viscera, are without the sense of touch. We have actual proof of this in what takes place when a horse is bled for the purpose of obtaining curative serum. With a sharp lance a cut may be made in the skin so quickly and easily that the animal does nothing more than twitch the skin-muscle of the neck, or give his head a shake, whilst of the further proceeding of introducing a hollow needle into the vein the animal takes not the slightest notice. Some horses, indeed, will stand perfectly quiet during the whole operation, munching a carrot, nibbling at a wisp of hay, or playing with a button on the vest of the groom standing at its head. "Harrowing details concerning the horrors of trephining rabbits for Pasteur's antirabic treatment are frequently supplied for popular consumption, but how little real existence any suffering in connection with the operation has, may be gathered from the fact that if, as a preliminary measure, the skin be benumbed with carbolic acid, the whole operation, from making the incision through the skin to cutting out the piece of bone with a fine trephine and passing a needle under the dura mater, may be done without once causing the animal to withdraw its attention from the important business of munching a bit of cabbage-leaf or a scrap of succulent carrot." (Prof. Woodhead, _Medical Magazine_, June 1898.) It may be well to put here--(1) the full text of the Act; (2) an account of the anæsthetics used for animals; (3) the latest Report of Government Inspectors appointed under the Act. 1.--AN ACT TO AMEND THE LAW RELATING TO CRUELTY TO ANIMALS _15th August 1876_ Whereas it is expedient to amend the law relating to cruelty to animals by extending it to the cases of animals which for medical, physiological, or other scientific purposes are subjected when alive to experiments calculated to inflict pain: Be it enacted by the Queen's most Excellent Majesty, by and with the advice and consent of the Lords Spiritual and Temporal, and Commons, in this present Parliament assembled, and by the authority of the same, as follows: 1. This Act may be cited for all purposes as "The Cruelty to Animals Act, 1876." 2. A person shall not perform on a living animal any experiment calculated to give pain, except subject to the restrictions imposed by this Act. Any person performing or taking part in performing any experiment calculated to give pain, in contravention of this Act, shall be guilty of an offence against this Act, and shall, if it be the first offence, be liable to a penalty not exceeding fifty pounds, and if it be the second or any subsequent offence, be liable, at the discretion of the court by which he is tried, to a penalty not exceeding one hundred pounds, or to imprisonment for a period not exceeding three months. 3. The following restrictions are imposed by this Act with respect to the performance on any living animal of an experiment calculated to give pain; that is to say, (1.) The experiment must be performed with a view to the advancement by new discovery of physiological knowledge or of knowledge which will be useful for saving or prolonging life or alleviating suffering; and (2.) The experiment must be performed by a person holding such license from one of Her Majesty's Principal Secretaries of State, in this Act referred to as the Secretary of State, as is in this Act mentioned, and in the case of a person holding such conditional license as is hereinafter mentioned, or of experiments performed for the purpose of instruction in a registered place; and (3.) The animal must, during the whole of the experiment, be under the influence of some anæsthetic of sufficient power to prevent the animal feeling pain; and (4.) The animal must, if the pain is likely to continue after the effect of the anæsthetic has ceased, or if any serious injury has been inflicted on the animal, be killed before it recovers from the influence of the anæsthetic which has been administered; and (5.) The experiment shall not be performed as an illustration of lectures in medical schools, hospitals, colleges, or elsewhere; and (6.) The experiment shall not be performed for the purpose of attaining manual skill. Provided as follows; that is to say, (1.) Experiments may be performed under the foregoing provisions as to the use of anæsthetics by a person giving illustrations of lectures in medical schools, hospitals, or colleges, or elsewhere, on such certificate being given as in this Act mentioned, that the proposed experiments are absolutely necessary for the due instruction of the persons to whom such lectures are given with a view to their acquiring physiological knowledge, or knowledge which will be useful to them for saving or prolonging life, or alleviating suffering; and (2.) Experiments may be performed without anæsthetics on such certificate being given as in this Act mentioned, that insensibility cannot be produced without necessarily frustrating the object of such experiments; and (3.) Experiments may be performed without the person who performed such experiments being under an obligation to cause the animal, on which any such experiment is performed, to be killed before it recovers from the influence of the anæsthetic, on such certificate being given as in this Act mentioned, that the so killing the animal would necessarily frustrate the object of the experiment, and provided that the animal be killed as soon as such object has been attained; and (4.) Experiments may be performed not directly for the advancement by new discovery of physiological knowledge, or of knowledge which will be useful for saving or prolonging life, or alleviating suffering, but for the purpose of testing a particular former discovery alleged to have been made for the advancement of such knowledge as last aforesaid, on such certificate being given as is in this Act mentioned that such testing is absolutely necessary for the effectual advancement of such knowledge. 4. The substance known as urari or curare shall not for the purposes of this Act be deemed to be an anæsthetic. 5. Notwithstanding anything in this Act contained, an experiment calculated to give pain shall not be performed without anæsthetics on a dog or cat, except on such certificate being given as in this Act mentioned, stating, in addition to the statements hereinbefore required to be made in such certificate, that for reasons specified in the certificate the object of the experiment will be necessarily frustrated unless it is performed on an animal similar in constitution and habits to a cat or dog, and no other animal is available for such experiment; and an experiment calculated to give pain shall not be performed on any horse, ass, or mule except on such certificate being given as in this Act mentioned that the object of the experiment will be necessarily frustrated unless it is performed on a horse, ass, or mule, and that no other animal is available for such experiment. 6. Any exhibition to the general public, whether admitted on payment of money or gratuitously, of experiments on living animals calculated to give pain shall be illegal. Any person performing or aiding in performing such experiments shall be deemed to be guilty of an offence against this Act, and shall, if it be the first offence, be liable to a penalty not exceeding fifty pounds, and if it be the second or any subsequent offence, be liable, at the discretion of the court by which he is tried, to a penalty not exceeding one hundred pounds, or to imprisonment for a period not exceeding three months. And any person publishing any notice of any such intended exhibition by advertisement in a newspaper, placard, or otherwise shall be liable to a penalty not exceeding one pound. A person punished for an offence under this section shall not for the same offence be punishable under any other section of this Act. _Administration of Law_ 7. The Secretary of State may insert, as a condition of granting any license, a provision in such license that the place in which any experiment is to be performed by the licensee is to be registered in such manner as the Secretary of State may from time to time by any general or special order direct; provided that every place for the performance of experiments for the purpose of instruction under this Act shall be approved by the Secretary of State, and shall be registered in such manner as he may from time to time by any general or special order direct. 8. The Secretary of State may license any person whom he may think qualified to hold a license to perform experiments under this Act. A license granted by him may be for such time as he may think fit, and may be revoked by him on his being satisfied that such license ought to be revoked. There may be annexed to such license any conditions which the Secretary of State may think expedient for the purpose of better carrying into effect the objects of this Act, but not inconsistent with the provisions thereof. 9. The Secretary of State may direct any person performing experiments under this Act from time to time to make such reports to him of the result of such experiments, in such form and with such details as he may require. 10. The Secretary of State shall cause all registered places to be from time to time visited by inspectors for the purpose of securing a compliance with the provisions of this Act, and the Secretary of State may, with the assent of the Treasury as to number, appoint any special inspectors, or may from time to time assign the duties of any such inspectors to such officers in the employment of the Government, who may be willing to accept the same, as he may think fit, either permanently or temporarily. 11. Any application for a license under this Act and a certificate given as in this Act mentioned must be signed by one or more of the following persons; that is to say, The President of the Royal Society; The President of the Royal Society of Edinburgh; The President of Royal Irish Academy; The Presidents of the Royal Colleges of Surgeons in London, Edinburgh, or Dublin; The Presidents of the Royal Colleges of Physicians in London, Edinburgh, or Dublin; The President of the General Medical Council; The President of the Faculty of Physicians and Surgeons of Glasgow; The President of the Royal College of Veterinary Surgeons, or the President of the Royal Veterinary College, London, but in the case only of an experiment to be performed under anæsthetics with a view to the advancement by new discovery of veterinary science; and also (unless the applicant be a professor of physiology, medicine, anatomy, medical jurisprudence, materia medica, or surgery in a university in Great Britain or Ireland, or in University College, London, or in a college in Great Britain or Ireland, incorporated by royal charter) by a professor of physiology, medicine, anatomy, medical jurisprudence, materia medica, or surgery in a university in Great Britain or Ireland, or in University College, London, or in a college in Great Britain or Ireland, incorporated by royal charter. Provided that where any person applying for a certificate under this Act is himself one of the persons authorised to sign such certificate, the signature of some other of such persons shall be substituted for the signature of the applicant. A certificate under this section may be given for such time or for such series of experiments as the person or persons signing the certificate may think expedient. A copy of any certificate under this section shall be forwarded by the applicant to the Secretary of State, but shall not be available until one week after a copy has been so forwarded. The Secretary of State may at any time disallow or suspend any certificate given under this section. 12. The powers conferred by this Act of granting a license or giving a certificate for the performance of experiments on living animals may be exercised by an order in writing under the hand of any judge of the High Court of Justice in England, of the High Court of Session in Scotland, or of any of the superior courts in Ireland, including any court to which the jurisdiction of such last-mentioned courts may be transferred, in a case where such judge is satisfied that it is essential for the purposes of justice in a criminal case to make any such experiment. _Legal Proceedings_ 13. A justice of the peace, on information on oath that there is reasonable ground to believe that experiments in contravention of this Act are being performed by an unlicensed person in any place not registered under this Act, may issue his warrant authorising any officer or constable of police to enter and search such place, and to take the names and addresses of the persons found therein. Any person who refuses admission on demand to a police officer or constable so authorised, or obstructs such officer or constable in the execution of his duty under this section, or who refuses on demand to disclose his name or address, or gives a false name or address, shall be liable to a penalty not exceeding five pounds. 14. In England, offences against this Act may be prosecuted and penalties under this Act recovered before a court of summary jurisdiction in manner directed by the Summary Jurisdiction Act. In England "Summary Jurisdiction Act" means the Act of the session of the eleventh and twelfth years of the reign of Her present Majesty, chapter forty-three, intituled "An Act to facilitate the performance of the duties of justices of the peace out of sessions within England and Wales with respect to summary convictions and orders," and any Act amending the same. "Court of summary jurisdiction" means and includes any justice or justices of the peace, metropolitan police magistrate, stipendiary or other magistrate, or officer, by whatever name called, exercising jurisdiction in pursuance of the Summary Jurisdiction Act: Provided that the court when hearing and determining an information under this Act shall be constituted either of two or more justices of the peace in petty sessions, sitting at a place appointed for holding petty sessions, or of some magistrate or officer sitting alone or with others at some court or other place appointed for the administration of justice, and for the time being empowered by law to do alone any act authorised to be done by more than one justice of the peace. 15. In England, where a person is accused before a court of summary jurisdiction of any offence against this Act in respect of which a penalty of more than five pounds can be imposed, the accused may, on appearing before the court of summary jurisdiction, declare that he objects to being tried for such offence by a court of summary jurisdiction, and thereupon the court of summary jurisdiction may deal with the case in all respects as if the accused were charged with an indictable offence and not an offence punishable on summary conviction, and the offence may be prosecuted on indictment accordingly. 16. In England, if any party thinks himself aggrieved by any conviction made by a court of summary jurisdiction on determining any information under this Act, the party so aggrieved may appeal therefrom, subject to the conditions and regulations following:--- (1.) The appeal shall be made to the next court of general or quarter sessions for the county or place in which the cause of appeal has arisen, holden not less than twenty-one days after the decision of the court from which the appeal is made; and (2.) The appellant shall, within ten days after the cause of appeal has arisen, give notice to the other party and to the court of summary jurisdiction of his intention to appeal, and of the ground thereof; and (3.) The appellant shall, within three days after such notice, enter into a recognizance before a justice of the peace, with two sufficient sureties, conditioned personally to try such appeal, and to abide the judgment of the court thereon, and to pay such costs as may be awarded by the court, or give such other security by deposit of money or otherwise as the justice may allow; and (4.) Where the appellant is in custody the justice may, if he think fit, on the appellant entering into such recognizance or giving such other security as aforesaid, release him from custody; and (5.) The court of appeal may adjourn the appeal, and upon the hearing thereof they may confirm, reverse, or modify the decision of the court of summary jurisdiction, or remit the matter to the court of summary jurisdiction with the opinion of the court of appeal thereon, or make such other order in the matter as the court thinks just, and if the matter be remitted to the court of summary jurisdiction the said last-mentioned court shall thereupon re-hear and decide the information in accordance with the order of the said court of appeal. The court of appeal may also make such order as to costs to be paid by either party as the court thinks just. 17. In Scotland, offences against this Act may be prosecuted and penalties under this Act recovered under the provisions of the Summary Procedure Act, 1864, or if a person accused of any offence against this Act in respect of which a penalty of more than five pounds can be imposed, on appearing before a court of summary jurisdiction, declare that he objects to being tried for such offence in the court of summary jurisdiction, proceedings may be taken against him on indictment in the Court of Justiciary in Edinburgh or on circuit. Every person found liable in any penalty or costs shall be liable in default of immediate payment to imprisonment for a term not exceeding three months, or until such penalty or costs are sooner paid. 18. In Ireland, offences against this Act may be prosecuted and penalties under this Act recovered in a summary manner, subject and according to the provisions with respect to the prosecution of offences, the recovery of penalties, and to appeal of the Petty Sessions (Ireland) Act, 1851, and any Act amending the same, and in Dublin of the Acts regulating the powers of justices of the peace or of the police of Dublin metropolis. All penalties recovered under this Act shall be applied in manner directed by the Fines (Ireland) Act, 1871, and any Act amending the same. 19. In Ireland, where a person is accused before a court of summary jurisdiction of any offence against this Act in respect of which a penalty of more than five pounds can be imposed, the accused may, on appearing before the court of summary jurisdiction, declare that he objects to being tried for such offence by a court of summary jurisdiction, and thereupon the court of summary jurisdiction may deal with the case in all respects as if the accused were charged with an indictable offence and not an offence punishable on summary conviction, and the offence may be prosecuted on indictment accordingly. 20. In the application of this Act to Ireland the term "the Secretary of State" shall be construed to mean the Chief Secretary to the Lord Lieutenant of Ireland for the time being. 21. A prosecution under this Act against a licensed person shall not be instituted except with the assent in writing of the Secretary of State. 22. This Act shall not apply to invertebrate animals. II.--ANÆSTHETICS UNDER THE ACT In almost every case, the anæsthetic used is chloroform or ether; sometimes it is combined with or followed by morphia or chloral. The nature of the anæsthetic used in each case must, of course, be stated in the returns sent to the Home Office. Of the use of ether, it need only be said that animals take it well, and that there is no difficulty in rendering them unconscious with it. With some animals, chloroform is equally good. Professor Hobday, of the Royal Veterinary College, published in 1898 an account of 500 administrations of chloroform to dogs, for operations, with only one death. Still, for dogs and cats, ether is used in preference to chloroform. Other animals take chloroform well. Morphia is seldom used alone; but, in some cases, it is used after chloroform or ether. That morphia is a "real anæsthetic" is certain, for there are deaths every year from an over-dose of it. Again, it is certain that an animal, so far under the influence of morphia that it lies still, cannot be suffering, for the drug does not act directly on the muscles but on the higher nervous centres. Very rarely a dog may fail to come readily under the influence of morphia, may be excited by it, not narcotized. But this is altogether exceptional. An animal in such a condition would not be suited for experiment, and another anæsthetic would be given. Except in these rare cases, animals take morphia well and are profoundly influenced by it. Curare is not an anæsthetic under the Act. It is illegal to use it as an anæsthetic. In this country it is seldom used at all, and it is never used alone in any experiment involving any sort or kind of painful operation. In every such case a recognised anæsthetic must be given, and is given.[43] [43] See Part IV., "Curare." A good account of curare was published in the _Edinburgh Review_, July 1899. "The Act of 1876 expressly forbids its use as an anæsthetic. When it is used, it must be supplemented with some other drug to relieve pain. A good deal of misconception exists as to the actual physiological effect of curare. Claude Bernard believed that it did not in any way affect the sensory nerves, and he described in theatrical terms the animal as being unable to stir, but suffering horrible torture. It is pretty certainly known now that Claude Bernard was wrong, and that, though curare acts first upon the motor nerves, it also, though less rapidly, paralyses the sensory nerves.... Probably the truth is, that, like all other nerve-poisons, the effect of curare varies with the dose. The muscular nerves are the first affected, then the sensory, and finally the central nervous system. As a matter of fact, however, morphia or some other narcotic is always given in addition to curare when it is used in laboratory work in England." III.--LATEST REPORT (1905) OF INSPECTORS UNDER THE ACT (The various tables of names, places, &c., and the references to them, which are contained in this Report, need not be reprinted here. The Report, and other papers relating to the Act, may be bought for a few pence from Wyman & Sons, Ltd., Fetter Lane, E.C.) * * * * * ENGLAND AND SCOTLAND _April 17th, 1906._ SIR,--I have the honour to submit the following Report on Experiments performed in England and Scotland during the Year 1905, under the Act 39 & 40 Vict. c. 77.... Six new places were registered for the performance of experiments, and one place was removed from the register during the year. All licensees were restricted to the registered place or places specified on their licenses, with the exception of those who were permitted to perform inoculation experiments in places other than a "registered place," with the object of studying outbreaks of disease occurring in remote districts or under circumstances which render it impracticable to perform the experiment in a "registered place." The total number of licensees was 381. Reports have been furnished by (or, in a few exceptional cases, on behalf of) these licensees in the form required by the Secretary for State. The reports show that 122 licensees performed no experiments. The numbers given above include 22 licensees whose licences expired on February 28, 1905, and who returned no experiments in 1905. Tables I., II., and III. afford evidence,-- 1. That licences and certificates have been granted and allowed only upon the recommendation of persons of high scientific standing; 2. That the licensees are persons who, by their training and education, are fitted to undertake experimental work and to profit by it; 3. That all experimental work has been conducted in suitable places. Table IV. shows the number and the nature of the experiments returned by each licensee mentioned in Table II., specifying whether these experiments were done under the licence alone or under any special certificate. Table IV. is divided into two parts, A. and B., for the purpose of separating experiments which were performed without anæsthetics from experiments in which anæsthetics were used. The total number of experiments included in Table IV. (A.) is 2506. Of these there were performed,-- Under Licence alone[44] 1348 " Certificate C. 145 " Certificate B. 665 " Certificate B. + EE 346 " Certificate B. + F. 2 [44] In experiments performed under licence alone, the animal must during the whole of the experiment be under the influence of some anæsthetic of sufficient power to prevent the animal feeling pain; and the animal must, if the pain is likely to continue after the effect of the anæsthetic has ceased, or if any serious injury has been inflicted on the animal, be killed before it recovers from the influence of the anæsthetic which has been administered. Certificate C. allows experiments to be performed, under the foregoing provisions as to the use of anæsthetics, in illustration of lectures. Certificate B. exempts the person performing the experiment from the obligation to cause the animal on which the experiment is performed to be killed before it recovers from the influence of the anæsthetic; and when the animal is a dog or a cat, Certificate EE. is also necessary. Certificate A. allows experiments to be performed without anæsthetics; and when the animal on which the experiment is performed is a dog or a cat, Certificate E. is also necessary. Certificate F. is required in all cases of experiments on a horse, ass, or mule. Table IV. (B.) is devoted entirely to inoculations, hypodermic injections, and some few other proceedings, performed without anæsthetics. It includes 35,429 experiments, whereof there were performed,-- Under Certificate A. 34,778 " Certificate A. + E. 549 " Certificate A. + F. 102 The total number of experiments is 37,935, being 5373 more than in 1904; the increase in the number of experiments included in Table IV. (A.) is 290, and in Table IV. (B.), 5083. All experiments involving a serious operation are placed in Table IV. (A.). The larger part of the experiments included in this Table, viz., all performed under licence alone, and under Certificate C., 1493 in number, come under the provision of the Act that the animal must be kept under an anæsthetic during the whole of the experiment, and must, if the pain is likely to continue after the effect of the anæsthetic has ceased, or if any serious injury has been inflicted on the animal, be killed before it recovers from the influence of the anæsthetic. In the experiments performed under Certificate B., or B. linked with EE. or with F., 1013 in number, the initial operations are performed under anæsthetics, from the influence of which the animals are allowed to recover. The operations are required to be performed antiseptically, so that the healing of the wounds shall, as far as possible, take place without pain. If the antiseptic precautions fail, and suppuration occurs, the animal is required to be killed. It is generally essential for the success of these experiments that the wounds should heal cleanly, and the surrounding parts remain in a healthy condition. After the healing of the wounds the animals are not necessarily, or even generally, in pain, since experiments involving the removal of important organs, including portions of the brain, may be performed without giving rise to pain after the recovery from the operation; and after the section of a part of the nervous system, the resulting degenerative changes are painless. In the event of a subsequent operation being necessary in an experiment performed under Certificate B., or B. linked with EE. or with F., a condition is attached to the licence requiring all operative procedures to be carried out under anæsthetics of sufficient power to prevent the animal feeling pain; and no observations or stimulations of a character to cause pain are allowed to be made without the animals being anæsthetised. In no case has a cutting operation more severe than a superficial venesection been allowed to be performed without anæsthetics. The experiments included in Table IV. (B.), 35,429 in number, are all performed without anæsthetics. They are mostly inoculations, but a few are feeding experiments, or the administration of various substances by the mouth, or the abstraction of a minute quantity of blood for examination. In no instance has a certificate dispensing with the use of anæsthetics been allowed for an experiment involving a serious operation. Inoculations into deep parts, involving a preliminary incision in order to expose the part into which the inoculation is to be made, are required to be performed under anæsthetics, and are therefore placed in Table IV. (A.). It will be seen that the operative procedures in experiments performed under Certificate A., without anæsthetics, are only such as are attended by no considerable, if appreciable, pain. The Certificate is, in fact, not required to cover these proceedings, but to allow of the subsequent course of the experiment. The experiment lasts during the whole period from the administration of the drug, or injection, until the animal recovers from the effects, if any, or dies, or is killed, possibly extending over several days, or even weeks. The substance administered may give rise to poisoning, or set up a condition of disease, either of which may lead to a fatal termination. To administer to an animal such a poison as diphtheria toxin, for example, or to induce such a disease as tuberculosis, although it may not be accompanied by acute suffering, is held to be a proceeding "calculated to give pain," and therefore experiments of the kind referred to come within the scope of the Act 39 & 40 Vict., c. 77. The Act provides that, unless a special certificate be obtained, the animal must be kept under an anæsthetic during the whole of the experiment; and it is to allow the animal to be kept without an anæsthetic during the time required for the development of the results of the administration that Certificate A. is given and allowed in these cases. It must not be assumed that the animal is in pain during the whole of this time. In cases of prolonged action of an injected substance, even when ending fatally, the animal is generally apparently well, and takes its food as usual, until a short time before death. The state of illness may last only a very few hours, and in some cases it is not observed at all. In a very large number of the experiments included in Table IV. (B.), the results are negative, and the animals suffer no inconvenience whatever from the inoculation. These experiments are therefore entirely painless. In the event of pain ensuing as the result of an inoculation, a condition attached to the licence requires that the animal shall be killed under anæsthetics as soon as the main result of the experiment has been attained. The number of inoculations and similar proceedings recorded in Table IV. (B.) continues to increase in accordance with the progressive importance attached to biological tests generally in practical medicine for the diagnosis, treatment and prevention of disease, and to the more widely recognised need for such experiments on the part of those responsible for the care of the public health. Several County Councils and Municipal Corporations have their own laboratories in which bacteriological investigations are carried on, including the necessary tests on living animals; and many others have arrangements by which similar observations are made on their behalf in the laboratories of Universities, Colleges, and other Institutions. A sewage farm is registered as a place in which experiments on living animals may be performed in order that the character of the effluent may be tested by its effects on the health of fish. The Board of Agriculture has two laboratories which are registered for the performance of experiments having for their object the detection and study of the diseases of animals. In other places experiments have been made on behalf of the Home Office, the War Office, the India Office, the Local Government Board, the Office of Works, the Board of Agriculture and Fisheries, and the Metropolitan Asylums Board. A very large proportion of the experiments in Table IV. (B.) have thus been performed either on behalf of Official Bodies with a view to the preservation of the public health, or directly for the diagnosis and treatment of disease. Forty-one licensees return over 8000 experiments which were performed for Government Departments, County Councils, or Municipal Corporations; 2187 experiments were made by four licensees for the Royal Commission on Tuberculosis; twelve licensees performed 6265 experiments, almost all inoculations, for testing antitoxic sera and vaccines and standardising drugs; and 12,187 experiments, mostly inoculations into mice, were performed on behalf of the Imperial Cancer Research Fund. The number of injections made during the year 1905 for the diagnosis of rabies in dogs is 27; these are placed in Table IV. (A.). During the year the usual inspections of registered places have been made by Sir James Russell, by myself, and by Mr. W. B. L. Trotter, who was appointed temporary Assistant Inspector during my absence for three months. We have found the animals suitably lodged and well cared for, and the licensees attentive to the requirements of the Act, as well as to the conditions appended to their licences by the Secretary of State. The irregularities recorded during the year have been few, and not of a serious character. Two licensees, holding certificates (A.) entitling them to perform inoculations without anæsthetics, administered an anæsthetic during some of their experiments, whereas the Act prescribes another form of certificate (B.) when an animal is anæsthetised during an experiment and allowed to recover from the anæsthetic. A licensee, through inadvertence, performed 54 inoculation experiments in excess of the number allowed by his certificate. Another licensee, not understanding that joint experiments are reckoned to both of the licensees, took part in the performance of eight experiments in excess of the number allowed by his certificate. By direction of the Secretary of State a suitable admonition was addressed to the licensee in each of the above cases. In the month of April 1905 the attention of the Secretary of State was directed to certain experiments which were performed in 1903 and the early part of 1904 by persons not holding a licence under the Act 39 & 40 Vict. c. 77. The experiments consisted in vaccinating dogs against distemper and then exposing them to infection, the object being to test the efficacy of a method of vaccination as a safeguard against this disease. The Secretary of State thereupon caused inquiries to be made, and from these it appeared that the experiments, in some instances at least, had been accompanied by pain, and were, therefore, illegal. The persons, who were not aware that their experiments were of such a kind as to come within the provisions of the Act, were suitably admonished and warned against any similar illegal action in the future. The matter was not brought to the knowledge of the Secretary of State until it was too late for further proceedings to be taken if such had been considered necessary. It is as well to point out here that to expose an animal to an infectious and painful disease like distemper is a proceeding calculated to cause pain within the meaning of the Act, and that such experiments can only be legally performed by a person holding a licence and appropriate certificates.--I have the honour to be, Sir, your obedient servant, G. D. THANE, _Inspector_. The Right Hon. HERBERT JOHN GLADSTONE, _Secretary of State for the Home Department_. IRELAND 8 ELY PLACE, DUBLIN, _April 26th, 1906_. SIR,--I beg to submit Tables showing the experiments performed in Ireland during the year 1905, under the Act 39 & 40 Vict. c. 77, together with a list of the Registered Places in Ireland. Twelve licences were in force during the year; of these four expired, and two were renewed. One new license was granted. The certificates in existence or allowed were:-- A. to 4 licensees. B. " 7 " C. " 3 " E. " 2 " EE. " 3 " F. " 1 licensee. One expired during the year, and six new ones were allowed. The experiments performed number 218; 106 being under licence alone, and 112 under certificates. Ten licensees performed experiments. Twenty certificates were in force among 12 licensees, of whom 10 performed experiments, viz.:-- Under Certificate A. 88 " " B. 14 " " C. 8 " " F. 2 The animals experimented on were:-- Guinea pigs 55 Birds 53 Rabbits 48 Cattle 27 Mice 14 Dogs 13 Cats 2 Horses 2 Goats 2 Sheep 2 The experiments were mainly pathological inoculations, done for the purposes of the investigation or diagnosis of various diseases, such as canine rabies, tuberculosis, cancer, glanders, and typhoid fever. A few were physiological, for the investigation of the functions of the thymus gland, and of the effects of chloroform and ether on renal activity. All of these seem to have been of a reasonable character and intended to serve useful purposes in the elucidation of the phenomena of disease or of vital functions. They are reported to have been free from pain. Experiments numbering eight were performed in illustration of lectures, to demonstrate the phenomena of circulation and respiration and of nervous control. In these experiments, two dogs, two cats, and four rabbits were employed. Some of the investigations were devoted to the study of diseases in cattle, horses, goats, and sheep, and seem to be useful and of economic value. The registered places were inspected and their condition found satisfactory. The inspectors in Belfast and Cork report that in those places the provisions of the Act have been satisfactorily complied with.--I have, &c., W. THORNLEY STOKER, _Inspector for Ireland_. To the Right Honourable The Chief Secretary to the Lord Lieutenant of Ireland. This Report gives a clear answer to certain false statements alleged against experiments on animals. It shows that more than 90 _per cent._ of these experiments are inoculations, with a few feeding experiments, administrations of substances by the mouth, or abstractions of a minute quantity of blood for examination. _In no instance has a certificate dispensing with the use of anæsthetics been allowed for an experiment involving a serious operation. In no case has a cutting operation more severe than a superficial venesection been allowed to be performed without anæsthetics._ It shows, also, that the results, in a very large number of these inoculations, are negative, painless, not even inconvenient. The Report shows, also, that the vast majority of all experiments are inoculations made on the smaller animals; and that the larger animals (dog, cat, horse, mule, or ass) are seldom used for inoculation. It shows, also, that a great proportion of these inoculations are made in the direct practical service of the public health and the public purse: to standardise drugs, to ensure the purity of food and of rivers, to protect flocks and herds, and to decide quarantine. Government Departments, County Councils, Municipal Corporations, and a Royal Commission made more than one-third of the total number of inoculations; and the Imperial Cancer Research Fund made more than one-third, mostly on mice; and a sixth was made over the testing and standardising of sera and of drugs. The operations performed under the License + Certificate B, or B + EE, or B + F, were 3 per cent. of the whole number of experiments. The majority of the animals were neither cats nor dogs. They can hardly be compared to the same number of the larger animals mutilated by breeders and farmers: for these mutilations may be inflicted, and are inflicted, without an anæsthetic. They can hardly be compared to the same number of pheasants or rabbits wounded, but not killed, in sport; for the animals wounded in sport get no subsequent care, and, if they are in pain, nobody need put them out of it. They may fairly be compared to the same number of pet animals that have undergone surgical operations, under anæsthesia, at the hands of a skilled veterinary surgeon; only with this difference, that many of them lose health, or suffer disablement or disease, and so die or are killed; but, if the wound suppurates, the animal must be killed, and, after the wound has healed, the animals are not necessarily, or even generally, in pain. And there must be no _further_ experiment without anæsthesia. _No observations or stimulations of a character to cause pain are allowed to be made without the animals being anæsthetised._ It is evident that good care is taken to ensure an irreducible minimum of pain. PART IV THE CASE AGAINST ANTI-VIVISECTION THE CASE AGAINST ANTI-VIVISECTION [The following pages are taken, with a few changes and omissions, from a pamphlet which I published in 1904. I am glad to say that the tone of the Anti-Vivisection Societies is not quite so bad as it was a few years ago; but I think that what I wrote in 1904 is still fairly accurate.] 1. ANTI-VIVISECTION SOCIETIES The early history of the anti-vivisection movement is given in a pamphlet by Dr. Leffingwell, of Brooklyn, entitled "The Rise of the Vivisection Controversy"; and in a pamphlet published by the National Anti-vivisection Society, entitled "Dates of the Principal Events connected with the Anti-vivisection Movement." Dr. Leffingwell calls attention to a fact not generally known--that the movement, in this country, was begun by the medical journals. The _Medical Times and Gazette_ in 1858, the _Lancet_ in 1860, and the _British Medical Journal_ in 1861 condemned in a very outspoken way certain experiments made on the Continent, and raised the question whether these or any experiments on animals could be justified. Later, in 1872, the _Medical Times and Gazette_ declared outright that all experiments, from the time of Magendie onward, had done nothing for humanity that could be compared to the discovery and use of cod-liver oil and bark. In 1874, the Royal Society for the Prevention of Cruelty to Animals took proceedings against those who had made certain experiments at Norwich during a meeting of the British Medical Association. These experiments, and the publication of the _Handbook of the Physiological Laboratory_, roused public comment; and during 1875 the opposition to all experiments on animals took more definite form. On June 22nd, 1875, the Royal Commission was appointed; on January 8th, 1876, its report was dated; and on August 15th, 1876, the present Act received the Royal assent. At the time when the Royal Commission was appointed, the only anti-vivisection society was that which Mr. Jesse had just started; and if any one will read Mr. Jesse's cross-examination, by Professor Huxley, before the Royal Commission, he will not attach much importance to that society. The National Anti-vivisection Society was founded in November 1875; the Irish Society, the London Society, and the International Association in 1876; the Church Anti-vivisection League in 1889, the Humanitarian League and the National Canine Defence League[45] in 1891, and the British Union about 1898. These dates show that the oldest of these societies came after the Royal Commission, not before it; the first societies and the Royal Commission were alike the expression of a widespread opinion, thirty years ago, that experiments on animals ought either to be forbidden or to be restricted. This same opinion had been favoured, fifteen years before that, by the representative journals of the medical profession. We have seen something of the work of the medical profession; let us now see something of the work of the societies. [45] These two societies have other purposes beside that of opposition to experiments on animals. The chief anti-vivisection societies in this country are the National Society, the London Society, the British Union, the Church League, and the Canine Defence League. In February 1898, the National Society declared itself in favour of restriction; it set before itself abolition as its ultimate policy, and restriction as its immediate practical policy. Thus, at the present time, these societies are divided into two parties: one asks for restriction, another asks for nothing short of abolition. This division between them, and the tone of the National Society toward the smaller Societies, waste their energy and their funds, and hinder them from working together. The National Society, in its official journal (January 1902), speaks as follows of this schism, in a leader entitled "The Folly of our Subdivisions":-- "Nobody seems to know how many Anti-vivisection Societies there are. A few hundred Anti-vivisectionists divide themselves up into divisions, subdivisions, coteries, and cliques, without order, without discipline, without cohesion. The Anti-vivisectionists between them all contribute but a few thousands a year, and dribble them around among multitudinous antagonistic associations.... The pitiful absurdity of the disunion fostered by some Anti-vivisectionists was illustrated very forcibly last year by the issue of a prospectus of a Society with a world-embracing title, in which its promoters declared that irreparable injury would be inflicted upon our cause if electoral work were not taken up by _them_.... The accounts of this stupendous organisation showed that its total expenditure for the year was £13, 19s. 4d., out of which ten shillings was devoted to 'electoral work.' ... A much graver injury is done to the cause of mercy by the deplorable waste of money spent in perfectly unnecessary offices and salaries. We say that one office would amply suffice for all the work, and that one office would not need half-a-dozen paid Secretaries. The existence of many quite needless Societies cannot be justified on any grounds of humanity combined with common sense." Nothing need be added to these very grave admissions, written by Mr. Coleridge himself. He proposes a very simple remedy for these "quite needless" societies:-- "The National Society, as the chief Anti-vivisection organisation in the world, is always ready to put an end to this grievous waste by receiving into its corporation any of the smaller Societies." But the leaders of smaller societies have two grounds of complaint against Mr. Coleridge's society: they do not believe in his policy, and they will not submit to his "discipline." They call his society "the weak-kneed brethren," and say that its policy is "miserable, cowardly, and misleading"; and they take it ill that he so often accuses them of inaccuracy. He refers again and again (see the official journal of the National Society) to this mode of discipline:-- _December 1901._--"I decline to be made responsible for the 'anti-vivisection party.' There happen to be small anti-vivisection associations whose chief occupation is the dissemination of quite inaccurate pamphlets. I have nothing to do with them, and cannot prevent anything they choose to do." _January 1902._--"Time after time has this sacred cause been undermined and betrayed by its professing friends by their reckless habit of making erroneous statements." _March 1902._--"I am quite aware that with many of my opponents in the exclusive total-abolition coterie, the motives that actuate them are far removed from the question of the salvation of the wretched animals, and have their foundation in emotions that seem to me singularly unworthy and petty." _May 1902._--"As representative of the National Society, I have again and again written to the representatives of some of the smaller anti-vivisection societies, protesting in plain terms against their publication of inaccurate statements." No society could submit to be thus taken to task four times in six months. The Church League writes to him, "What the Church League may or may not think fit to say does not in the very least concern you, who are not a member of the League. Interference in such a matter from an outsider is an obvious impertinence." Such rejoinders are met, in their turn, by angry leaders, "A Stab in the Back," "Stabs in the Back," in the National Society's official journal; and the Hon. Secretary of the London Society, who is a lady, is accused of want of chivalry for Mr. Coleridge. The leader, "A Stab in the Back" (April 1902), is a curious instance of the tone of one anti-vivisection society toward another:-- "The time when a man is assailed by a large section of the press, threatened with violence by laymen, attacked on points relevant by vivisectors and points irrelevant by their supporters, is scarcely the moment that a generous rival would have chosen for hurling a dart; and yet, incredible as it may appear, the Honorary Secretary of another Anti-vivisection Society, seizing an opportunity afforded by an article in the _Globe_, enters the arena, and, by a letter repudiating any connection with Mr. Coleridge, appears to sanction the unfriendly criticisms expressed in that paper. It needed no chivalry to refrain from writing such a letter. A small amount of good taste would have amply sufficed.... This letter, which will convince the public of nothing but the writer's lack of taste, might well be ignored were it not that it is but one of the many attacks made by members of other societies, either by open statement or innuendo, against the Honorary Secretary of the National Society." But we cannot wonder at these occasional stabs. For the National Society does not stop at charging other societies with inaccuracy. It makes yet graver charges against them. Here are three made by Mr. Coleridge's society against Miss Cobbe's and Mr. Trist's societies:-- _March 1901._--"The February number of the _Abolitionist_ contains a leading article in which allusions are made to subjects that are never discussed by decent people even in private. As the leading organ of the Anti-vivisection movement, we enter our solemn protest against the publication of this unspeakable article, which must inevitably inflict the gravest injury upon our cause." _February 1903._--"It is our duty to inform our readers that Mr. Trist has published the correspondence, but that he has mutilated it, omitting some of his own letters altogether, and excising whole paragraphs of Mr. Stewart's letters." _June 1903._--"Our amiable contemporary, the _Abolitionist_, is good enough, in a long article in its last issue, to suggest to those preparing the libel action against Mr. Coleridge what are the most vulnerable points in his armour." Thus divided in policy, and quarrelling among themselves, these societies are still agreed in appealing to the public for approval and for money. Here the London Society's opposition to the National Society comes out clearly. In its annual report (1903) the London Society says:-- "Join a really effective Society with a frank and straightforward policy--namely, the London Anti-vivisection Society, 13 Regent Street, London, S.W. This is a National and International organisation. It has greater medical support than any other. It is the most 'alive' humane organisation in the world.... Get into touch with the society. Write to us. We shall be glad to hear from you and answer any questions." "If you can provide for the Society's future in your Will, may we beg of you to do so? If you agree, pray do it now. Thousands of pounds have been lost to the Society and the Cause by the fatal procrastination of well-meaning friends. The pity of it! Legacies should be left in these _exact_ words: 'To the _London_ Anti-vivisection Society.' CAUTION. It is of great importance to describe very accurately the _Title of this Society_--namely, THE LONDON ANTI-VIVISECTION SOCIETY--otherwise the benevolent intentions of the Donor may be frustrated. PLEASE NOTE.--Those charitable persons who have left money to the Society would do well to notify the same to the Secretary." Contrast the tone of this appeal for money with the tone of the Report:---- "Your Society are glad to note that the Christian Churches are becoming alarmed at the pretensions of scientific authority.... The Christian laity has been largely uninstructed or misinformed on this grave question.... Happily, the signs of the times are propitious; not all of the leaders of religious thought in this country have succumbed to the dictation and pretensions of the professors of vivisection ... a base and blatant materialism, a practice which owes its inception to barbarism, and which has developed in materialism of the lowest possible order." Surely such eloquence should avail to tear the money even out of the hands of the dying, lest the National Society should get it. The National Society, oddly enough, also says: "CAUTION.--It is of great importance to describe very accurately the _Title of this Society_--namely, THE NATIONAL ANTI-VIVISECTION SOCIETY--otherwise the benevolent intentions of the Donor may be frustrated." I do not know which of these two societies is the inventor of this phrase. Still, it is not improbable that the National Society receives more money than all the smaller societies together. Of course, we cannot compare the working expenses of an anti-vivisection society with the working expenses of the Society for the Prevention of Cruelty to Animals, or the Society for the Prevention of Cruelty to Children. The former of these two societies in one year obtained 8798 convictions; in one month alone, 689 convictions; and it paid the full costs of committing 34 of the 689 to prison. The Society for the Prevention of Cruelty to Children has an equally good record. But an anti-vivisectionist society cannot show results of this kind. Nor can we compare its working expenses to those of a missionary society; for the missionaries give direct personal service to their fellow-men. But we can fairly compare an anti-vivisection society to an anti-vaccination society or a Church of Christian Science. That is to say, it is a publishing body. In 1902, the National Society's expenditure, in round numbers, was £970 on printing and stationery; £1193 on rent, salaries, and wages; £1255 on books, newspapers, periodicals, &c., including the _Illustrated Catalogue_ and the _Hospital Guide_; £1380 on lectures, meetings, organising new branches, &c.; and about £500 on all other expenses. Let us take, to illustrate these figures, what the National Society says from time to time in its official journal:-- _June 1899._--(From the Society's Annual Report): "The whole controversy has been collected and published in pamphlet form by your Society, and more than 10,000 copies have already been issued to the public. Over 200 people have joined your ranks and become members of the Society in consequence of it, while two cheques of £1000 each were received by Mr. Coleridge in aid of the cause." _June 1899._--"We have received more money within the past six months than we got in any two years previously." _June 1899._--"We cannot better employ the funds at our disposal than in securing the constant help of experts to insure the accuracy of all our statements, and in sending well-informed lecturers to every city in the kingdom." _June 1900._--(From the Society's Annual Report): "The receipts of the society from subscriptions and donations show an increase over those of the previous year. This increase in itself, however, would hardly have justified the increase in the expenses which it has been found necessary to incur in almost every department, and especially in the distribution of pamphlets and papers, had it not been for some legacies which fell due, notably one from----, of £6386." _May 1901._--"With heartfelt gratitude we have once more to announce that the National Society has received a gift of a thousand pounds from an anonymous donor. Nothing could be more opportune for the Cause than this munificent support, coming as it does just as the issue of 20,000 copies of Mr. Stephen Coleridge's _Hospital Guide_ has been made at so great a cost to the Society." _June 1901._--"Our editorial table is buried deep in press cuttings from all parts of the kingdom." _March 1902._--"We employ two press-cutting agencies to send us cuttings from the journals of the whole English-speaking world." _July 1903._--"We start branches in various towns, and send lecturers to speak at working men's clubs and debating societies. All this means a very large expense. We very often issue a pamphlet likely to do good by the tens of thousands. Last year we issued 50,000 copies of the 'Illustrated German Catalogue of Vivisectional Instruments and Appliances.'" The smaller societies, of course, spend their funds in the same sort of way. Thus the National Canine Defence League says that its anti-vivisection work, the most important of all its works, is earnestly carried forward by (1) The Writer's League, in a ceaseless flow of letters to the press; (2) The circulation of lists of hospitals free from the shameful practice; (3) The publication of twenty-one strong leaflets on the subject; (4) The circulation of 300 copies of a book on the subject. This society in two years sent out 650,000 leaflets and pamphlets; but they were not all of them about experiments on animals. Another Society, in a report published in 1902, enumerates the methods which it employs for "the education of the public at large." These include (_a_) the publication of literature; (_b_) the holding of public meetings in all parts of the United Kingdom; (_c_) the delivery of lectures with or without limelight illustrations; (_d_) participation in debates even with high scientific authorities; (_e_) inducing the clergy and ministers of all Churches to deliver sermons dealing with the subject; (_f_) organisation of a press bureau, through which the newspaper press of the country is watched, and correspondence and articles contributed. This Society has also a van, "the only one of its kind in existence. No sooner is our winter and spring campaign concluded than the van takes up the thread of the work and carries it on through the summer, and it may truly be said that the track of the van across country is white with the literature which the van circulates on its educational mission." It is evident, from these and the like statements, that these Societies, during the last quarter of a century, have published a vast quantity of literature. We must examine the style of that literature during some recent years, and the arguments which it puts forward. But, before we do this, let us consider what attitude is taken by these Societies, or by well-known members of this or that Society, toward certain problems and interests that closely concern them. I They do not hesitate to take advantage of all those improvements of medicine and surgery which have been made by the help of experiments on animals. They denounce the work of the present; but they enjoy all the results of the past, and will enjoy all those of the near future. "If anything of value to medicine has been discovered by vivisection, it would be as absurd to reject it on that account as it would be to abandon Ireland because centuries ago we took it by force." And again: "We are no more morally bound to reject benefits acquired by indefensible means than are the descendants of slaveholders bound to abandon wealth originally acquired by the detestable abomination of slavery." And again, the _Animal's Friend_ (November 1903) takes as further instances the benefits derived from body-snatching, political assassination, and the French Revolution. But, in the matter of experiments on animals, it is the very same men and women who denounce these experiments and who profit by them. What should we say of an anti-slavery reformer who was himself drawing a vast income out of the slave trade? But there is one gentleman, and, so far as I know, only one, who did carry his opinions into practice. He told the story at a debating meeting--how his little girl had a sore throat, and the doctor wanted to give antitoxin, and he forbade it, and the child recovered. "Of course," he says, "it was only an ordinary sore throat." Truly, a great victory, and a brave deed, to make an experiment on your own sick child. II The attitude of these Societies toward sport may seem at first sight purely negative; but it is worth study. I have the honour of knowing a very eminent physiologist who will never shoot, because he thinks it cruel--a man much abused by the National Society. And Lord Llangattock, the President of that Society, is well known as an a "ardent sportsman." This contrast is of some interest. Let us see what the National Society says about sport. Of course, it is not bound to attack sport. But the reasons which it gives for remaining neutral are to be noted. 1. It says, very truly, that it is in great part supported by sportsmen. 2. It says, further, that the cruelties of sport lie outside its own proper work:-- "Our opponents frequently ask us why we do not attack some form of cruelty other than vivisection, which they consider more heinous. Our Honorary Secretary recently summarised this argument in his own amusing manner thus: We must not arrest the man in Tooting for kicking his wife till we have stopped the woman in Balham starving her children, and we must not arrest the woman in Balham for starving her children until we have stopped the man in Tooting kicking his wife." (1901.) Later (1903) the _dramatis personæ_ are a man in East Islington jumping on his wife, and a woman in West Islington stabbing her husband. But this argument, of course, will not hold. For it is the same men who denounce wounds made (under anæsthetics) for physiology, and who make wounds (without anæsthetics) in sport. 3. It says that the "object" of the sportsman is to kill; but the "object" of the experimenter is to torture:-- "There is a vast difference between the killing of animals and the torturing of them before killing them. The object of the sportsman is to kill his quarry; the object of the vivisector is to keep his victim alive while he dissects it."--Mr. Wood (1903). "The object of the sportsman is to kill, and the object of the vivisector is to keep his victim alive while he cuts it up."--Lord Llangattock (1901). "The vivisector is nothing if not a tormentor; the sportsman is not a true sportsman if he seeks to inflict pain on his quarry.... One (the pain of a horse falling on asphalt) is the result of an accident to be deplored, the other (the pain from an experiment) is done of devilish malice prepense."--Leader in the Society's official journal, (1899). "I am not so mentally and ethically confused as to be unable to distinguish between the entirely different moral acts of killing and torturing."--Mr. Coleridge (1901). Here are four statements. One is by Mr. Wood, the Society's lecturer; one by Lord Llangattock, its President; one is published in its official journal; and one is by Mr. Coleridge, its honorary secretary and treasurer. That is the sort of thing which seems good enough to the National Society to say to its friends in Parliament; this childish nonsense about the true sportsman and his quarry. III The attitude of these Societies toward the medical profession, and toward the Hospitals, must be studied. Let us look through some numbers of the official journal of the National Society, and see the attitude that it sometimes takes toward the medical profession:-- _June 1899._--"The charm of this sort of thing is that you are always sure of the _post-mortem_ if of nothing else." _July 1899._--"There is a disease, well known to the vestrymen of London, called 'the half-crown diphtheria.' This is common sore throat, notified as diphtheria because the vestry pays a fee of half-a-crown to the medical notifier." _December 1899._--"The patient died, made miserable by the effect of inoculations which even on bacteriological grounds gave no promise of success, but the scientific physician, nowadays, must inject something in the way of a serum." _March 1901._--"There will always be those who, unable to think for themselves or exercise their independence on therapeutic methods, are prone to bow down before authority which is self-assertive enough to compel the obedience of weak minds. Such men would inject antitoxin though every case died. They administer it not knowing why." _April 1901._--(From "Our Cause in the Press"): "What effort does the medical profession make to make clear to its clients what is well known to itself, that disease is the result of wrong living? Practically none at all. The medical profession as a whole have winked at sin, and have merely sought to antidote its results." _September 1901._--"Some day we shall have our surgeons disembowelling us just to see what daylight and fresh air will do for the stomach-ache." _December 1901._--"The new medicine demands a mere laboratory habit; the patient is nothing, the disease everything. He is a test-tube; such and such reagents are needed to produce a certain result, and there you are. The patient's malady, be it what it may, is due to a microbe, a toxin, or a ptomaine; he must be inoculated with the serum or antitoxin which counteracts his disease, and this must be done not _secundum artem_ but _secundum scientiam_, and the science means the inoculating syringe and so many cubic centimetres of filth wherewith to poison the man's blood and so cure his disease, though the victims die." _December 1903._--(From "Our Cause in the Press"): "Not only did we see great callousness in the field hospitals in South Africa, but conversation with the class that finds its way into our hospitals in England will reveal that a great deal of refined cruelty is constantly occurring." Why does the official journal of Mr. Coleridge's society publish these things? For this reason--that it must attack those methods that were discovered by the help of experiments on animals. The medical profession uses these methods. Therefore, that profession must be attacked. The same reason, of course, helps to explain the National Society's attack on the great Hospitals of London. It would take too long to tell here the whole story of that attack. Three charges were made against the Hospitals: (1) that they maltreat patients; (2) that they promote the torture of animals; (3) that they endow this torture at the cost of the patients. They were accused, to put it plainly, of treachery and fraud; and of course the Council of the King's Hospital Fund got its share of abuse. Mr. Coleridge said on this subject:-- 1. (Annual meeting at St. James's Hall, May 1901): "How have Lord Lister, the vivisector, and his Committee distributed the Prince of Wales's Hospital Fund? They have so distributed this fund as to make it clear to hospital managers that the more they connect their hospitals with the torture of animals the larger will be the grant they may expect to get from the Prince of Wales's Fund. That fund, therefore, has been used as an insidious but powerful incentive to vivisection." 2. (Annual meeting at St. James's Hall, 1902): "Sheltering itself now in its most repulsive form behind those ancient and glorious institutions, founded and sustained for their Christ-like work of healing the sick, sapping their foundations and smirching their fair fame, malignant cruelty has taken up its position in its last ditch. There it has summoned to its aid vast interests, ancient prejudices, enormous endowments, and under illustrious patronage it has pilfered the funds subscribed for the poor." With these statements before us (and it would be easy to add to them) we cannot doubt that the plan of campaign against all experiments on animals is also hostile to the Hospitals, whenever that hostility seems likely to be of the very least use to the cause. * * * * * Surely there are charities more worthy of subscriptions, donations, and legacies than these Anti-vivisection Societies. They quarrel among themselves; they spend vast sums of money on offices, salaries, press-cuttings, reprints, lectures and meetings, tons of pamphlets and leaflets. Their members denounce all experiments done now, while they enjoy the profit of all experiments done before now; they say that the object of the physiologist is to torture his victim out of devilish malice prepense; they accuse doctors of fraud, and lying, and refined cruelty, and madness, and winking at sin; they blacklist and boycott the best Hospitals. And the whole costly business, these thirty years, has done nothing to stop these experiments; they have increased rapidly. Surely, if a man wishes to help and comfort animals, he had better give his money to the Home for Lost Dogs, or the Home of Rest for Horses. II. LITERATURE. We have now to examine the style of the literature of these societies. But, out of such a vast store of journals, pamphlets, and leaflets, we can only take one here or there. From time to time a book or a pamphlet is, for good reasons, withdrawn. Thus, in 1902, the London Society withdrew _Dark Deeds_. (_The Shambles of Science_, now impounded, was published by a chairman of committee of the National Society, but not by that society.) In 1900 the National Society withdrew one or more pamphlets involving acceptance of Dr. Bowie's mistranslation of Harvey. In 1902 it withdrew and destroyed a whole store of diverse pamphlets, and appealed to its supporters to "refrain from circulating any literature not issued from our office by the present committee"; that is to say, it warned them to distribute no literature but its own, and not all even of that. But the withdrawal of a few books and pamphlets makes very little difference; and most of them are "revised" and brought out again. Take, for example, the _Nine Circles_. It was planned and compiled for Miss Cobbe; Mr. Berdoe was "urgently requested by her to point out to her any scientific errors or possible inadvertent misrepresentations of fact, and correct or expunge them"; and he "carefully read through the proof-sheets." The book purported to be an exact account, from original sources, of certain experiments, some made abroad, some in this country. It was attacked by Sir Victor Horsley at the Church Congress at Folkestone, October 1892, and was withdrawn, revised, and brought out again. Our only concern here is to see what the official journal of the National Society said of the revised issue. This official journal, the _Zoophilist and Animal's Defender_, was started in May 1881, under the shorter title of the _Zoophilist_. It speaks of itself as a "scientific journal," and as "the recognised organ of the anti-vivisection movement in England." It is published monthly, and may be obtained through any bookseller. In 1883 it was edited by Miss Cobbe; in 1884 by Mr. Benjamin Bryan; in 1898 by Mr. Berdoe. In 1903, Mr. Coleridge, apologising for an error made in it in 1898, says: "At that time I had not the control over its pages that is at present accorded to me." Thus it is, I believe, still edited by Mr. Berdoe, and is, or was in 1903, controlled by Mr. Coleridge. And we are bound to note here that Mr. Berdoe was in great part responsible for the _Nine Circles_; and in 1897 was responsible for certain statements as to the use of curare, which the Home Secretary, in the House of Commons, called "absolutely baseless." Let us now examine the style of this "official journal." And, to begin with, what does it say about the _Nine Circles_? To make this point clear, let us put in parallel columns what was said by Sir Victor Horsley of the original edition in 1892, and what was said by the _Zoophilist_ in 1899 of the revised edition:-- _Sir Victor Horsley, Oct. 1892._ I have taken the trouble to collect all the experiments in which cutting operations are described as having been performed by English scientists, and in which I knew anæsthetics to have been employed. These experiments are 26 in number. In all of them chloroform, ether, or other anæsthetic agent was employed. But of these 26 cases, Miss Cobbe does not mention this fact at all in 20, and only states it without qualification in two out of the remaining six. When we inquire into these 20 omissions in the 26 cases, we find in the original that again and again Miss Cobbe has, in making her extracts, had directly under her eyes the words "chloroform," "ether," "etherised," "chloroformed," "anæsthetised," "during every experiment the animal has been deeply under the influence of an anæsthetic," and so forth. _The "Zoophilist," July 1899._ A revised edition has been issued, which is a stronger indictment against the vivisectors than the original work. There were some half-dozen omissions in the first edition concerning the administration of anæsthetics in the preliminary operations, but the cruelty of the experiments was in no case modified by the fact that a whiff of chloroform was possibly administered, as stated in the reports, at the beginning of the operation. Our opponents may boast of their success in detecting the omission to dot the i's and cross the t's in the first edition of the _Nine Circles_, but there are some victories which are worse than a defeat. We have replaced the lantern with which we examined the dark deeds of the laboratories by the electric searchlight. The "researcher" will find it hard to discover a retreat where its rays will not follow and expose him. For another instance of the inaccuracy of the _Zoophilist_ we have what it said about Professor Sanarelli's experiments in South America on five human beings. Nobody defends him here. But the point is that the _Zoophilist_ in 1899 said that they had all been killed; and in 1902 admitted that they had all recovered. Or, for another instance, we have what it said in 1902 about the case of His Majesty the King. (For these statements, see _Zoophilist_, August 1902 and September 1903; also its report, October 1902, of Mr. Wood's speech at Exeter.) But let us take a wider view. A journal, like a man, is known by the company that it keeps. Whose company does the _Zoophilist_ keep? Why does it talk of _Our excellent cotemporary, Humanity_--_Our valiant cotemporary, Le Médecine_--_Our excellent cotemporary, The Herald of the Golden Age_? Again, among the journals that it quotes, some of them very frequently, are the _Topical Times_, _Broad Views_, _Modern Society_, _Madame_, the _Humanitarian_, the _Pioneer_, the _Vegetarian_, the _Voice of India_, the _Herald of Health_, the _Rock_, the _New Age_, the _Journal of Zoophily_, the _Homoeopathic World_, _Medical Liberty_, and the _Honolulu Humane Educator_. This may be very good company, but it is not all of it the best company for a "scientific journal." Still, it may be better company than the American _Medical Brief_, the _Journal de Médecine de Paris_, and the Belgian _Le Médecine_. These journals, being veritable "medical journals," are quoted in the _Zoophilist_ with the most amazing frequency and at great length; which is a compliment that they do not receive from other medical journals. They are, indeed, as vehemently anti-Pasteur and anti-antitoxin as the _Zoophilist_ itself. Take what the _Medical Brief_ says:-- "Bacteriology originated in Continental Europe, where the minds of a superstitious race were further unbalanced by constant delving in pathology, putrefaction, and morbid anatomy. When it spread to the new world, it also became blinded with the revolutionary and fanatical tendencies lying near the surface in such a civilisation." "They say if you give a calf rope enough, he will hang himself. Bacteriology is equally clumsy and stupid.... What excuse can be found for the cowardice and ferocious ignorance which, under the shadow of the stars and stripes, resurrects the sentiment of the Middle Ages to protect the fraud, seeks to rob the individual physician of free judgment, and denounces him for failing to use the nasty stuff?" "All Continental Europe is suffering from a sort of leprosy of decadence, mental and moral. The spiritual darkness of the people affects all the learned professions, but more especially medicine." Such is the _Medical Brief_, which the official journal of Mr. Coleridge's society quotes incessantly, calling it "an American monthly of great ability and without a trace of the scientific bigotry and narrow-mindedness which is so prominent a feature in some of our own organs of medical opinion." Next we come to the _Journal de Médecine de Paris_. This is anti-Pasteur; the editor, Dr. Lutaud, came to London in 1899, and gave a lecture on "the Pasteur superstition" at St. Martin's Town Hall. From a report of it in the _Star_ we may take the following sentences:-- "The result of the serum craze had been that the hospital was neglected for the laboratory. Microbes of all the diseases were found in perfectly healthy subjects. Microbes existed, but as a consequence, not a cause. Toxins which the seropaths professed to find were only the results of normal fermentation. The English public had always supported him in his fifteen years' struggle against Pasteurism." Dr. Lutaud, says the National Society, is "the great authority." The _New England Anti-vivisection Monthly_ in 1900 calls him one of "the brightest scientists of modern times." His _Journal de Médecine de Paris_ recalls the _Medical Brief_:-- "To wish to apply the same methods of treatment, whether preventive or curative, for two morbid conditions (a _wound_ with the point of entry _abnormal_ and an infectious _malady_) in essence so different, is to commit a gross error.... The sick are destroyed by that which cures their wounds." These two "medical journals," the _Medical Brief_ and the _Journal de Médecine de Paris_, are upheld by the National Society as though they were expert witnesses of irresistible authority, and are quoted with a sort of ceaseless worship in that Society's official journal. Also it quotes the _Herald of Health_; and _Medical Liberty_, "a monthly publication issued by the Colorado Medical Liberty League, Denver, Colo., whose eloquent editor seems to be an uncompromising foe to medical bigotry and monopoly, and humbugs of every description." Such are the medical journals which support the _Zoophilist_ as a scientific journal. Now let us take another point of view. Let us consider whom the _Zoophilist_ praises, and whom it condemns. That, surely, is a fair test of an official journal. And we get a clear result. The late Lord Salisbury and Mr. Arthur Balfour are "notoriously pro-vivisectionist"; Lord Lister has "apostatised from the anti-septic faith"; M. Pasteur is a "remorseless torturer"; the late Mr. Lecky was "degenerate," because he "performed the _volte-face_ and went over to our opponents"; and the late Professor Virchow was subjected to "scathing criticism" by one Paffrath, and was proved to be absurd. But its praises are given to a very different set of men. There is no room here to note the lighter moods of the _Zoophilist_; its jokes about cats and catacombs, and two-legged donkeys and four-legged donkeys, and how to catch mosquitoes by putting salt on their tails--and it will even _break its jest on the dead_--but it rebukes another journal for levity, saying, _We regret to see our_ _painful subject treated in this manner._ No room, either, for its description of anti-vivisectionist plays, poems, novels, and sermons. Let us, to finish with, take a few statements from its pages, almost at random; some of them are reprinted there from other sources. The supply is endless; let us limit ourselves to six of them:-- 1. "As other bacteria (beside those of malaria) were found not to bear sunlight or air, but to habitats in _loca scuta situ_ (? to inhabit _loca senta situ_), in filth and noisomeness, their habits and customs preached again the old doctrine, 'Let in sun and air and be clean,' as earnestly as those who thought health was due to sun and air and water and fire, the four old elements, and act accordingly, without dissecting hecatombs of animals to prove a thousand times over that if you boiled or baked or drowned or freezed living creatures they would die, or that microscopic parasites did pretty much what visible parasites have been always known to do." (Loud applause)--Report of a speech by the Bishop of Southwell (1901). 2. "It is just as well that you should have heard what the clever level-headed lawyer (Mr. Coleridge) thinks about this abominable conspiracy of cruelty and fraud and impious inquisitiveness which is called vivisection. (Cheers.) ... We are sending out on the world in every direction multitudes of young men who have been trained as surgeons, and they have lived by cutting (reference here to the medical students in _Pickwick_), and we are sending these young men out with this _cacoëthes secandi_, this mania for cutting for the mere sake of cutting. I should not be surprised if they tackle our noses or our ears, and set about mutilating us in that way."--Archdeacon Wilberforce (1901). 3. "The task of the crusader against vivisection is not to reason with the so-called scientist, not to truckle to pedants in the schools, or palter with callous doctrinaires, but to inform and arouse the people; and when John Bull is prodded from his apathy, and startled from his stertorous snore, he will rise and bellow out a veto on the elegant butcheries of pedantic libertines, and rush full tilt with both his horns against their abattoirs of cruelty and passion, pharisaically vaunted as research, until the gates of hell shall not prevail against him."--The Rev. Arthur Mursell (1901).[46] 4. "It has been my experience of anti-vivisection among Romanists, that nothing suited my purpose better than taking it for granted that the worshippers of St. Francis, St. Bernard, &c., must, _of course_, be on our side."--(1902.) 5. "Given money, and influential patronage, the vivisector now expects a time after his own heart, while professedly engaged in investigating the supposed causes of cancer, or the transmissibility of tuberculosis. He can inflict the most horrible and prolonged tortures on miserable animals, with such a plausible excuse in reserve, that he is endeavouring all the while to find cures for the ailments of high personages and millionaires."--(1902.) 6. "The day of drugging and scientific butchery is drawing to a close. Already the calm, reassuring voice of the new Life Science, loud and clear to the few, is faintly audible to the many. The sharp, crucial knife, with its dangerous quiver so dear to the heart of the surgeon, the poisonous drug, will be things of the past. Wisdom, thy paths are harmony and joy and peace."--(1902.) [46] Even the _Zoophilist_, which quotes this speech from the _Clapham Observer_, seems to feel that it might have been put more simply. * * * * * Such is the frequent level of the _Zoophilist_, the official journal of the National Society, edited by Mr. Berdoe, controlled by Mr. Coleridge. Let us now take one more of that society's publications, a pamphlet entitled _Medical Opinions on Vivisection_. Here, if anywhere, should be the society's stronghold. If it could show a large and important minority of the medical profession opposed to all experiments on animals, its power would be greatly increased. On three occasions, many years ago, the medical profession did express its opinion. At two of the annual meetings of the British Medical Association, and at a meeting of the London International Medical Congress, resolutions were passed affirming the value and the necessity of these experiments. At one of these meetings there was one dissentient vote; at one, two;[47] at one, none. These three meetings were truly representative; they were the great meetings of the clans of the profession, from all parts of the kingdom, for a week of practical work tempered by festivities. What more could any profession do than to go out of its way three times that it might record, in fullest assembly, its belief? And most certainly it would do the same thing again, if it thought that any further declaration were needed. [47] I think it was two; it was either one or two. There are in this country about 40,000 medical men. The National Society's pamphlet quotes 39, or one in 1000. It could quote more; but we must take what it gives us. Of these 39, we may fairly exclude Professor Koch, Sir Frederick Treves, and the late Sir Andrew Clark, who would certainly wish to be thus excluded. Sir Frederick Treves, who is quoted with a sort of explanatory note, has told us in the _Times_ what he thinks of the way in which his name has been used; Sir Andrew Clark is quoted, also with an explanatory note, for an _obiter dictum_; and Professor Koch for no discoverable reason. That leaves 36. Of these 36, at least 11 (probably more) are dead; one died about 1838, another was born in the eighteenth century, another died more than twenty years ago. Of the remaining 25, one is Dr. Lutaud, one is Mr. Berdoe, one an American doctor, not famous over here, one a veterinary surgeon, one (I think) opposed to vaccination, and three inclined to homoeopathy; one has mistranslated Harvey to the advantage of the National Society's cause, one has written _Hints to Mothers_, and one has written _How to Keep Well_. Of these 25 gentlemen, one belongs to a homoeopathic hospital, two to provincial hospitals, and one to a hydropathic institute and a children's sanatorium; the rest of them hold no hospital or school appointment of any sort or kind. I may be wrong over one or two of these names; but, so far as I can see, I have given an exact account of the value of these _Medical Opinions on Vivisection_. And, if we take the dates of these opinions, we find one in 1830, one in 1858, and seven in 1870-1880. Anyhow, what is the value of an opinion that all experiments on animals are _arrant and horrible Sepoyism wearing the mask of Art and Science_? Let us leave the National Society, and turn to the Canine Defence League, and examine that part of its literature which is concerned with experiments on animals. Take the following sentences from pamphlets 179 and 204:-- "Among the general public the majority are under the impression that these so-called physiological experiments are conducted under the influence of anæsthetics, and that the subjects are rendered insensible to pain; this, however, is _not the case_, and I am informed that a large proportion--considerably more than half--of the licenses dispense with anæsthetics entirely. The phenomena of pain are absolutely essential to any practical issue." "All diseases have a mental or spiritual origin. Upon this subject a large treatise might be written. I have carefully thought this matter over, and can come to no other conclusion. Can we imagine any wild bird confined to its nest with rheumatism, or neuralgia, or consumption, or asthma, or any other affection whatever? I believe them all to be entirely free from disease; that is, all which have retained their freedom, and thus have not come under the baneful influence of man. Take, again, the fishes, and ask whether any fisherman ever caught a fish found to be diseased. This subject is an interesting, though a somewhat melancholy one." Next, as an example of the literature of the London Society, let us take a speech made at St. James's Hall, May 26, 1903, by Dr. Hadwen, of Gloucester, who is also vehemently opposed to vaccination. He and Lieutenant-General Phelps, at the time of the disastrous smallpox epidemic in Gloucester in 1896, were leaders of the anti-vaccinationists. It would be easy to give other instances of the sympathy between anti-vivisection and anti-vaccination. But our business is not with Dr. Hadwen at Gloucester, but with him at St. James's Hall. He says to the London Society:-- "We are told we must pay attention to what the experts tell us. My opinion is this: If there is one person in the whole of God's creation that wants looking after, it is the expert. (Laughter.)" Of the House of Commons, he says:-- "If there is one thing in the world that will move a member of Parliament, it is to know that any particular policy will carry votes along with it. (Hear, hear.) You can bring any member of Parliament to your knees as long as you show him that he has his constituency at his back; and with all due respect to our noble chairman, I am bound to say that my experience of members of Parliament is this--that their consciences go as far as votes, and do not extend very much farther." (Laughter and applause.) He describes an imaginary experiment under curare, and is interrupted by a cry of "Demons!" He goes on:-- "Yes, madam, they are demons. (Applause.) I know no other word to describe experimenters who can submit sentient and sensitive creatures, almost human in intelligence and faith, to diabolical experiments, whilst their victims are rendered helpless and voiceless by a hellish drug. (Applause.) I cannot understand how in a land like this, that boasts of her Christianity and of her liberty, men, women, clergy, and politicians can allow this cowardly science to stand before us, and this demoniacal work to be carried on. (Loud cheers.)" * * * * * We have now seen something of the style of the literature of these Societies; and, in the next chapter, we will consider its arguments. I do not deny that its style is sometimes at a higher level than the examples which I have quoted. But I do say that I could fill a book of 100 pages with quotations from journals or pamphlets of the last few years, all of them on the lower level. And in this chapter I have practically quoted nobody but those who are the leaders of the opposition to all experiments on animals. The official journal of this Society, the annual report of that Society, the leaflets which are sent in answer to a formal request for literature--I have quoted these, as they came to hand, just going through them and marking those passages which were to my purpose. III. ARGUMENTS We have seen that the societies arose out of the Act, and not the Act out of them; that they are divided or hostile; and that they have next to nothing to show for all the vast sums which they have received. Also we have noted the style of literature which they send broadcast over the country; and the "medical journals" and "medical opinions" that are in favour of the cause; and the general tone and frequent level of the official journal of the National Society. Still, a good cause may be ill served; nobody minds, after all, the style of a thing, so long as it is true. Let us come to the heart of the matter. What is the nature of the arguments and evidences of these societies? They desire to bring about the absolute prohibition, as a criminal offence, of all experiments on animals. By what facts, what records, what statistics, do they maintain this attempt to mend or end the present Act? Here, at the risk of repetition, let me make quite clear what they are fighting against. Nine out of ten experiments are bacteriological. That is to say, 90 or 95 per cent. Of these inoculations, more than a third are made in the direct service of the national health, and as it were by the direct orders of Government. A vast number of them are wholly painless; nothing happens; the result is negative; the thing does not take. Some are followed by disease, and the animal is painlessly killed at the first manifestation of the disease, or recovers, or dies of the disease. The fate of that animal is the fate of all of us; it has got to die of something, and it dies of it. Anyhow, the talk about torture-troughs and cutting-up has no place here; and the word vivisection, by a gross and palpable abuse, is false nine times out of every ten. Of the remaining 10 per cent. of all experiments; in those that are made under the License alone, or under the License _plus_ Certificate C, the question of pain does not arise. The animal is anæsthetised, and is killed under that anæsthetic. The remaining 3 per cent. of all experiments are those that are made under the License _plus_ Certificate B (or B + EE, or B + F). The initial operation is done under the anæsthetic; the animal is allowed to recover; it may be, practically, none the worse for it. Or it may be the worse for it, and therefore die, or be killed. But Certificate B is _not_ allowed for any infliction of pain on the animal through the operation wound, and never will be. Here are two sets of experiments: those under Certificate A, and those under Certificate B. One is 90 per cent. of all experiments; the other is 3 per cent. Nine out of ten experiments are inoculations, and the operation of the tenth is done under an anæsthetic. That is the first fact, which we must fix in our minds, before we consider the arguments of the societies. Next, the dates and the sources of their evidence. They wish to stop the experiments that are now made in this country. They are bound, therefore, to produce "up-to-date" evidence, and from home sources; not that which is thirty years old, or comes from sources far away. This present use of animals, here and now, under the restrictions of the Act, is what they are fighting; they are bound to draw their instances from here and now. But this would not suit them at all: they could not bear to be thus limited to here and now. Their arguments and their instances extend over thirty or more years, and are drawn from all parts of the world, from the United Kingdom, the United States, France, Germany, Italy, from every country. Journals of Physiology, text-books, reports, medical journals, British and foreign, are ransacked to find evidence for the cause; there is a regular system, year in year out, a sort of secret service or detective force, a persistent hunting-up of all scraps and shreds of evidence. One society advertised, in a daily paper, that it wanted confidential communications, from medical students, as to the practices of the laboratory. Another, seeing the chance of a prosecution, says, "Special inquiries were made on the subject, and the society's solicitor went to Belfast to conduct these inquiries on the spot." All this espionage is sure now and again, in thirty years, to detect something which it can magnify into a scandal. And when a fault is found, even a little one, oh the joy in the ranks of the societies. And, at once, the fault, exaggerated, and highly coloured, is made a _locus classicus_, a commonplace of every drawing-room meeting. What is the date of it, what was the place of it? Was it long ago, was it far from here? Still, never let it drop; what one did then, they are all doing now, all of them of malice prepense; let us proclaim the blessed news from every platform; and please remember us in your Wills. Among the arguments against all experiments on animals, is this very common argument, that the truth about them is too horrible to be told. "We dare not produce our brief," says the Rev. Nevison Loraine, at the annual meeting of the London Society in 1901; "it is only the courage of a lady that dares to produce tales so harrowing as those that have been briefly alluded to to-day; and it is part of the weakness of our cause with the public that we cannot tell the whole story." But, not long ago, the courage of two ladies, officers of a Swedish Anti-vivisection Society, honorary members of Mr. Coleridge's society, did produce a book full of harrowing tales; they told the whole story to the Lord Chief Justice and a jury. Was not that producing their brief? _I have here in my pocket something I have not got the nerve to read to you_, says Archdeacon Wilberforce, at the annual meeting of the National Society in 1901; and the next minute a lady in the audience is crying out, _Do not go on, we cannot bear it_; and he says, _You have got to bear it. Good God, they have got to suffer it._ Is not that producing his brief? Mr. Coleridge, in 1902, sends out 12,000 copies, just to begin with, of an illustrated German catalogue of laboratory instruments: _The question of thus scattering abroad this fearful document has been the subject of very grave consideration.... We have launched upon the world this terrible proof of what vivisection really is, with a full sense of our responsibility._ Is not that producing his brief? These things in the pocket, and fearful documents, and briefs that Mr. Loraine dares not produce, are apt to say little or nothing about anæsthetics, and to be silent over the fact that nine out of every ten experiments are bacteriological, and to over-emphasise experiments made many years ago or a thousand miles away. You bring the speaker down to now and here, to the text of the Act, to the reports to Government, to the Home Secretary's own words in Parliament; and you are told that they are all in a conspiracy, all liars more or less, and that the truth is in the societies, especially in one of them. Or you bring him down to the good that these experiments have done, the lives that they have saved; and at once he is off like the wind:-- "The society does not concern itself with the results of vivisection, whether good or bad, and thinks it is beside the mark to discuss them." (Report of the Canine Defence League, 1903.) "When the angel of pity is driven from the heart; when the fountain of tears is dry, the soul becomes a serpent crawling in the dust of the desert." (Colonel Ingersoll.) "I make no pretence to criticise vivisectional experiments on the ground of their technical failure or success. I dogmatically postulate humaneness as a condition of worthy personal character." (Mr. Bernard Shaw.) "The vivisector, when he stands over his animal, whether with anæsthetics or without anæsthetics, is creating, even if the physical health of the nation is enhanced by it, a moral shroud not only for himself, but a moral shroud the edges of which are continually extending into the thought atmosphere, and so deadening the national conscience at large." (Mr. Herbert Burrows.) "The developed taste for blood and cruelty must in the end find its full satisfaction in the vivisection of human beings when they have the misfortune to come under the power of our future doctors." (Bishop Bagshawe.) Here, in these five sentences taken merely out of the heap, is the ethical argument; so facile, so pleasant to self, so confident of a good hearing. No wonder that the societies, now that the facts of science are too strong for them, are falling back on the facts of ethics. In the beginning, thirty years ago, they were created out of ethics; they were born auspiciously. What a welcome they had! Tennyson and Browning and Ruskin, Westcott and Martineau, the late Lord Shaftesbury, and her Majesty the late Queen--these all, and many more, among whom were some of the best men and women of the Victorian Age, were their friends. There never was a cause that enjoyed a better send-off. Everything was in its favour. Magendie and Schiff and Mantegazza had made people sick of experiments on animals. The advocates of the method had not very much to show on its behalf; no bacteriology, save as a far-off vision; no great discoveries lately in physiology or pathology. Thirty years ago, good and true men fought a way for the Act; and there are few now who think the worse of them for it, or grudge them that victory. But, though ethics may be the same always, yet the arguments from them are not. The ethical argument now--we try to find it, and it takes all shapes, and vanishes in a cloud of foul language. That text about the sparrows, which is never quoted in full; that fear about the vivisection of hospital patients; and all that nonsense about moral shrouds, and serpents in the desert, and developed tastes for blood; and Mr. Bernard Shaw, who on May 22nd, 1900, suggests to the National Society that "_the laceration of living flesh quickens the blood of the vivisector as the blood of the hunter, the debauchee, or the beast of prey is undoubtedly quickened in such ways_,"[48] and a week later, before the London Society, dogmatically postulates humaneness as a condition of worthy personal character; and the lady who says, _Oh, Pharisees and hypocrites! Oh, cruel and ruthless egotists!_ and the Falstaff's army of the osteopath, and the fruitarian, and the _anti_ this, that, and the other, who follow the cause; and all these discordant societies, and the begging for money--where, in all this confusion, can we find the ethical argument? Mercy is admirable, but I will wait till mercy and truth are met together. Let us leave the societies to their ethics, and see what they have to say for themselves in the lower realms of science. [48] Mr. R. B. Cunninghame-Graham's variant on this theme, in the _Daily News_, Aug. 27, 1903, is really too filthy to be put here. Like Mr. Loraine, I dare not produce my brief. I First, there are the general arguments. That experiments on animals are useless, or of very little use; that they contradict each other; that you cannot argue from animals to men, or from an animal under experiment to a man not under experiment; that the discoveries made by the help of experiments on animals might have been made as well, or better, without that help; that the way to advance medicine and surgery has been, and is, and always will be, not by experiments on animals, but by clinical and _post-mortem_ studies. These and the like arguments we may call general; they are the complement of the horrible stories and magic-lantern slides of the itinerant lecturer. 1. The vague statement that these experiments are of little use, may be answered in several ways. It does not come well from those who say that the question is ethical, not utilitarian; who neither know, nor care, nor are agreed, what is the real value of these experiments. "I challenge you," says one, "to show me what good they have done." Another says, "I admit that they may perhaps have done a little good; but so little; they are a bad investment; you would get a better return from other methods of work." Another says, "I don't care whether they have or have not done good; this is a matter of conscience; we must not do evil that good may come; I grant all, or nearly all, your instances--malaria, and diphtheria, and cerebral localisation, and so forth; but the question is a moral question, and we must not inflict pain on animals, save for their own good." Probably the best answer is, that good has indeed come, and is coming, and so far as we can see will come, out of these experiments; that the instances given are indeed true; that these results were won out of many failures, and contradictions, and fallacies, and harkings-back; and that they have stood the test of time, and will underlie all better results, all surer methods, that shall take their place. 2. The statement that "you cannot argue from animals to man" is not true. Why should it be? Take tubercle, tetanus, or rabies. The tubercle-bacillus is the same thing in a man, a test-tube, or a guinea-pig; the virus of rabies is transmitted from dogs to men; oysters harbour typhoid, fleas carry the plague, diverse mosquitoes carry malaria, yellow fever, filariasis, and dengue. Take the circulation of the blood, the nature and action of the motor centres of the brain, the vaso-motor nerves, the excretory organs, the contractility of muscle, the blood-changes in respiration--where are the differences to support this statement that you cannot argue from animals to men? 3. The twin statements, that all the results got by the help of experiments might have been got some other way, and that clinical study and _post-mortem_ study are infinitely more fruitful than experimental study, may be taken together. We are told that anybody could have discovered the circulation by injecting the vessels of a dead body. Well, Malpighi tried to discover the capillaries by this method, and failed. We are asked to admit that phrenology, long before physiology, discovered the truth about the surface of the brain; _I have been told_, says Mr. Coleridge at an annual meeting of his society, _that the physiologists can now triumphantly map out the human brain. I think the phrenologists have always been able to do that, and whether they or the vivisectors do it best does not much matter._ We are told that the use of thyroid extract could have been discovered right away by mere chemistry and thinking. We hear of a proposal for a bacteriological laboratory on anti-vivisectionist principles, where no inoculations shall be made. This argument, that the whole thing might have been done some other way, must repair its wit, and find better instances. Then comes the incessant appeal: "Stick to clinical work; study diseases at the bedside, in the _post-mortem_ room, in the museum, anywhere but in the laboratory. The Hospital taught you to neglect these methods; it made experiments on its patients, it cheated the public, it sheltered malignant cruelty in its most repulsive form under illustrious patronage. Set aside pathology; just sit by your patients long enough; that is the way of discovery." Or the appeal takes another tone: "Stick to sanitation. If only everybody were healthy, everybody would be well. Diseases are due to dirt, to vice, to overcrowding, to want of common-sense. Abolish all slums, disinfect all mankind, body and soul, make every house clean and wholesome, no bad drainage, or ventilation, or water, or food. Leave your torture-chambers, and open your eyes to the blessed truth that, if everybody were healthy, and everybody were good, everybody would be well." What is the use of talking in this way? Suppose that all the physiologists suddenly rushed into practice, and all the bacteriologists were turned into medical officers of health. What would be gained? What difference would it make? The physiologists, of course, would merely vivisect their hospital patients; and the bacteriologists would hardly feel the change, for many of them are medical officers of health already, public servants, appointed by the State. This argument, that practice is fruitful of discoveries, and science is barren of them, reaches its highest absurdity in the National Society's official journal; which praises extravagantly those methods of practice which were not discovered by the help of experiments on animals; praises them without experience, criticism, or understanding. It finds a statement, in the _Medical Annual_, that a year has passed without any great improvement in practice; and at once it lays the blame not on practice but on science. It fights hard against a fact which began in science, though it has been proved a thousand times over in practice. It accuses the bacteriologists now of caring nothing for human suffering, now of rushing after every new method of treatment and flooding the market with drugs. _There is money in the business_--that is the phrase of the _Zoophilist_. But there is money, also, in the anti-vivisection business. _If you can provide for the society's future in your will, may we beg of you to do so? If you agree, pray do it now_, says the London Society: _this is the most alive humane organisation in the world_. But the National Society says, _A grave injury is done to the cause of mercy by the deplorable waste of money spent in perfectly unnecessary offices and salaries. We say that one office would amply suffice for all the work, and that one office would not need half-a-dozen paid secretaries._ II Let us leave the general arguments and come to the special arguments. Some of them are concerned with the experiments themselves, some with the men who made them, some with the administration of the Act. These special arguments must be arranged in some sort of order; but they cross and recross, and are of diverse natures, and any attempt at strict arrangement would fail. That the arrangement may be useful for immediate reference, and may help anybody to answer statements made at debates and lectures, a separate heading has been given to each argument. Those arguments are put first which are concerned with the experiments themselves, or with the men who made them; afterward come those which are concerned with the administration of the Act. HARVEY "It is perfectly true," says Mr. Berdoe, "that Harvey again and again, in the plainest terms, declares that his experiments on living animals aided him in his discoveries." I agree here with Mr. Berdoe. Then comes this sentence: _But that is not so important as it appears to be_. Why not? What is gained by this attempt to explain Harvey away? Dr. Bowie mistranslates him; Dr. Abiathar Wall half-quotes him; Mr. Adams says that Harvey did not ascribe his discoveries to experiments on animals; Mr. Berdoe says that he did; and Mr. Berdoe's society withdraws every pamphlet that involves acceptance of Dr. Bowie's mistranslation. Why should we take, on Harvey's work, any opinion but that of Harvey? SIR CHARLES BELL For the argument from Sir Charles Bell's words, and for the truth about his work, see Part I., Chap. VII. CEREBRAL LOCALISATION Mr. Berdoe says that it is "pure nonsense" to argue from the motor areas of a monkey's brain to those of a man's brain. Why is it nonsense? What is the difference between the movement of a group of muscles in a monkey's arm and the same movement of the same group of muscles in a man's arm? With a very weak current, so weak that it is not diffused beyond the area where it is applied, the surface of a monkey's brain is stimulated at one spot; and forthwith its opposite arm is flexed, or its opposite leg is drawn up, or whatever the movement may be, according to the spot. A man has some disease, acute or chronic, of his brain; and, as the disease advances, twitchings occur in one arm or one leg, little irrational useless movements, or rigidity, or loss of power, according to the case. Is it pure nonsense to believe that the disease has reached a certain spot on the surface of his brain? There is no question here of the mental differences between men and monkeys; no question of consciousness or of will. But Dr. Holländer, who thinks very highly of Gall's system of phrenology, says, _Is the laboratory-man, the experimental physiologist, to teach us the mental functions of the brain from his experiments on frogs, pigeons, rabbits, dogs, cats, and monkeys?_ That is the argument; that we must not compare the monkey's motor areas with the man's motor areas, for we cannot find the mind of a man in the brain of a frog. But, putting aside phrenology, which is a broken reed for anti-vivisection to lean on, what other arguments are urged against the facts of cerebral localisation? First, that the speech-centres were discovered without the help of experiments on animals. That is true; and there, practically, the work of discovery stopped, till experiments on animals were made. Next, that the physiologists have not always been agreed as to the facts of cerebral localisation; that Charcot doubted them, that Goltz criticised Munk, and so on. What is the date of these doubts and criticisms? They are twenty years old. Next, that the surgery of the brain often fails to save life. That is true; and the anti-vivisection societies make frequent use of this fact. But they are unable to suggest any better method. Mr. Berdoe tells us that he cannot remember hearing, in his student days, anything about brain-experiments on animals:-- "Our work was to observe as closely as possible the symptoms and physical signs exhibited by patients in the hospital wards who suffered from any form of nerve or brain disease, and having carefully noted them in our case-books, to avail ourselves, when the patient died, of any opportunity that was offered us in the _post-mortem_ of correcting our diagnosis." That is an exact picture of the state of things thirty years ago; the student taking notes, waiting for the _post-mortem_ examination, then correcting his notes there, etc. Every case of brain-tumour in those days died, but many are saved now; and every case of brain-abscess in those days died (one or two were saved by a sort of miracle of surgical audacity); but many are saved now. ANTITOXINS AND CARBOLIC ACID It is said by opponents of experiments on animals, that the active principle, in antitoxin, is not the antitoxin, but the carbolic acid which is added to it. They take this statement from the _Medical Brief_; and we have learned something of the style of that journal. Here is a sentence from the official journal of the National Society:-- "The _Medical Brief_ calls antitoxin 'the fraud of the age,' and says: _Would that physicians could all realise the hideous horror of using this nasty stuff as a remedial agent_. It would be nothing less than ghoulishness to inject the matter from an abscess into a child's arm, yet antitoxin is not much better; it is the decomposing fluid from a diseased horse, partially neutralised by carbolic acid." For a commentary on this sentence, take the following letter from an eminent bacteriologist:-- "As regards diphtheria antitoxin, the addition of an antiseptic is by no means necessary or universal. For fully two years I added none to the serum which I prepared, but contented myself with filtration through a Kieselguhr filter, and bottling under aseptic conditions. At one time Roux used to put a small piece of camphor in each bottle as some sort of safeguard against putrefaction. Nowadays I believe that most makers preserve their sera by adding a trace of trikresol--I am not quite sure of the amount, but it is either .04 per cent. or .004 per cent.!" But it is probable that the _Zoophilist_ will still accept the authority of the _Medical Brief_. Baccelli got good results, in tetanus, from the administration of carbolic acid; therefore, in diphtheria, the good results from diphtheria-antitoxin are due to the carbolic acid in it. That is the argument. But there is no carbolic acid in it? Oh, then the patient got well of himself, the treatment didn't kill him, it was not diphtheria after all, the disease has altered its type lately, he was well nursed, the back of his throat was painted with something, the doctor got half-a-crown by calling it diphtheria, the bacillus diphtheriæ may be found in healthy mouths, and all bacteriology is _base and blatant materialism_. THE ARGUMENT FROM THE DEATH-RATE There is another argument against diphtheria-antitoxin; we may call it, for brevity, the death-rate argument. It is this. _The doctors say that the antitoxin does save lives; they give us statistics from every part of the world. But, if it saves lives, then the total mortality ought to go down. But the Registrar-General's returns do not go down; indeed, they tend to go up. Therefore diphtheria-antitoxin is useless, or worse than useless._ By this kind of logic, umbrellas are useless. If they were useful, then the more umbrellas there were, the less rain there would be. But the increase in umbrellas coincides with a positive increase of rain. Therefore umbrellas are useless, or worse than useless. Despite the absurdity of this argument, Mr. Coleridge and Mr. Somerville Wood, the National Society's lecturer, have worked hard with it; Mr. Coleridge in the press, Mr. Wood on the platform. Surely this confusion between the total mortality and the case-mortality of an epidemic disease is a very serious offence. That there may be no doubt of the confusion, let us consider a set of quotations, out of a correspondence published in September-October 1902, between G. P., whose initials we may take to mean general practitioner, and Mr. Somerville Wood. This correspondence is a good instance of the argument in its usual form:-- G. P.: "The antitoxin treatment of diphtheria has lessened the mortality from that disease by nearly 50 per cent. In the hospitals of the Metropolitan Asylums Board the average case-mortality for the last five years of the pre-antitoxin period, _i.e._ previous to 1895, was 30.6; that for 1895 and the successive four years was 18.1, the successive figures being 22.8, 21.2, 17.7, 15.4, and 13.6, the mortality steadily falling with increased familiarity with the use of the remedy. This has not been the result of a diminished virulence of the disease, as similar experience has been gained all over the world. The figures for Chicago are even more striking, as the averages are 35.0 and 6.79 for the pre-and the post-antitoxin periods respectively." Mr. WOOD: "Nowadays, almost every sore throat is called diphtheritic, antitoxin is given, and wonderful statistics are formulated to bolster up the latest medical craze. The real test is whether the introduction of antitoxin has lowered the death-rate generally from diphtheria. Here are the Registrar-General's figures: In 1887, the death-rate from diphtheria per million persons in this country was 140. In 1897, after the treatment had been used several years, the death-rate from this disease increased to 246 per million." G. P.: "Mr. Wood's statistics do not vitiate my argument in the very slightest. His selected figures, using the lowest rate since 1881, merely show that diphtheria as a whole was more prevalent in 1897 than in 1887. He cannot and does not attack the statement that the case-mortality has been lessened where antitoxin has been used, and his test is no test at all." Mr. WOOD: "Let me give the annual death-rate from diphtheria to a million living persons from 1881 to 1900, taken from the Registrar-General's returns." (Gives them.) G. P.: "One last word in answer to Mr. Wood. I repeat that his figures show nothing more than the accepted fact that diphtheria as a whole has been increasing for the last 30 years. This has no bearing at all on the also accepted fact that where antitoxin is used the mortality is lessened, and Mr. Wood has not, in fact, denied this. His confusion of total mortality and case-mortality only shows that he does not understand the elementary principles of statistics." A few weeks later, at the _Bournbrook and Selly Oak Social Club_, Mr. Wood gives his "thrilling lecture, with lantern views," _Behind the Closed Doors of the Laboratory_: one of his stock lectures. In it, he says:-- "The proof of the pudding was in the eating. In 1881 the death-rate from diphtheria was 127 per million; in 1900 it was 290 per million. He had but to state that the antitoxin treatment was introduced about 1894." Four days later, at an _overflowingly-attended Citizen Social_ at Birkenhead:-- "The proof of the pudding lay in the eating. In 1881 in each million of the population 121 persons died from diphtheria, while in 1900 the mortality from the same disease was 290 persons in each million of the population, and the antitoxin treatment was introduced in 1894." A few weeks later, at Ipswich, the same thing. This time, he is challenged by letters in the _East Anglian Daily Times_, and again quotes the Registrar-General. A few weeks later, at the _Hyde Labour Church_: the _Closed Doors of the Laboratory_ again:-- "He found from the Registrar-General's returns that the death-rate had gone up in cases in which they were told that wonderful things had been done by experiments on living animals. If a lower death-rate could be shown, then the vivisectionists might have something to go upon; but they could not show a lower death-rate." That was in January 1903. In December 1903, Mr. Wood is still using the same argument; this time it is a lecture at Ashton on _Vivisection and the Hospitals_: "Again and again had they defied the so-called scientific world to put their finger on the Registrar-General's returns, and show them a single instance where the death-rate had been lowered by vivisection, and they had not been able to do it. On the contrary, he found that the death-rate had gone up in the last 20 years, despite the thousands of animals that had been experimented upon. The death-rate in diphtheria was 100 per million more than it was in 1878." Mr. Wood in the provinces, and Mr. Coleridge in the papers, have used this argument hard. Let us look at it well. It has been refuted again and again. Take a thousand cases of diphtheria from any civilised part of the world, in the days before antitoxin; how many of them died? Take a thousand cases now, treated with antitoxin; how many of them die? Why do Mr. Wood and Mr. Coleridge run away from that easy question? There is nothing unfair in it; they have all the reports before them; they know the facts well. We do not find any evidence that they are willing to acknowledge the truth of those facts. Follow Mr. Somerville Wood, from place to place, with his magic-lantern and his stock of lectures. The lantern-pictures are many of them taken from foreign sources, and some of them are of great age; but they include a portrait of Mr. Coleridge, and some comic slides to be shown at the end of the lecture, rabbits vivisecting a professor, and so forth. Certainly, he works hard; 95 lectures in one year; _we cannot better employ the funds at our disposal than in sending well-informed lecturers to every city in the kingdom to rouse the just indignation of the people_. The year after that, 74 lectures; _on two occasions he has spoken when unsupported to over 1000 people, and an audience of several hundreds is quite the rule_. Here he is at Windsor, with Bishop Barry in the chair, and he says to them:-- "Unhappily, Pasteur left his microscope and chemicals and took up the vivisectionist's knife. In that he got utterly astray and became nothing more than a mere quack." Here, with a different audience, at the Mechanics' Lecture Hall, Nottingham, giving his lantern-lecture on _Pasteurism_ to a _most respectable audience of working men, their wives, sons, and daughters, and in many cases children_. "The thesis he set out to elaborate and maintain was that Pasteurism produces hydrophobia rather than cures it; that vivisection under any circumstances is both cruel and immoral; and that with special reference to bacterial toxicology and the treatment by inoculation, the preparation of toxins by the Pasteur methods was the most horrible form of repulsive quackery and hideous cruelty." Here he is at Birmingham, asking for money, and hinting that, unless all experiments on animals are stopped, _the poor will be the ultimate victims_. Here, at Gloucester, saying that _it is silly to experiment at all_, and that he is not going to take his views as to right and wrong from any man of science, however learned he may be. Here, at Edinburgh, with the _Closed Doors_ again, and the picture of the rabbit "roasted alive": three grains of opium, he tells them, would be enough to kill the strongest navvy in Edinburgh, but 16 grains can be administered to a pigeon; and the death-rate has gone up every year in spite of vivisection. Here, at a drawing-room meeting, asking for money; here, at a garden party, with a _considerable number of persons ranging themselves on the grass_, and he tells them that they have on their side all that is best in every department of public life; here, at Blackburn, with the _Closed Doors_ again, calling the law _a sham and a farce_; here, at Cheltenham, with Bishop Mitchinson in the chair, still quoting the Registrar-General, and saying that _he does not think the outlook was ever more promising than it is to-day_. All over the kingdom, he and his magic-lantern, year after year, goes Mr. Wood. He is a fluent speaker; he has things in his pocket; they are brought out, if you contradict him; or he "challenges" you, or explains you away, or says that you "are not quite playing the game." Let him alone; to-morrow he will pack up his lantern, and be gone. Mr. Coleridge, in his use of the death-rate argument, carries it even further than Mr. Wood; for he applies it over a wider range. "Look at myxoedema," he says; "the doctors tell us that they can cure it with thyroid extract, and that the use of thyroid extract was discovered by the help of experiments on animals. Very good. Myxoedema is due to some fault in the thyroid gland. Very good. But here are the Registrar-General's returns of the annual death-rate for all diseases of that gland. See, the death-rate has gone up, steadily, during the last 20 years." Was there ever such an argument? It is only of late years that myxoedema has been generally recognised. Till it was recognised, it was not diagnosed; till it was diagnosed, it was not returned as a cause of death. Again, there are many other diseases of the thyroid gland, including various forms of malignant disease. It is cancer of the thyroid gland that decides the death-rate. The number of deaths from myxoedema, especially since the discovery of thyroid extract, must be small indeed. Moreover, apart from Mr. Coleridge's fallacy of argument, it is impossible to see how he can really doubt the efficacy of the thyroid treatment, both in myxoedema and in sporadic cretinism. Again, "Look at the diseases of the circulation," he says. "The doctors say that digitalis and nitrite of amyl act on the heart; and that the action of these drugs was discovered by the help of experiments on animals. Very good. The heart is concerned with the circulation. Very good. But here are the Registrar-General's returns of the annual death-rate for all diseases of the circulation. See how it has gone up, from 1371 per million persons in 1881 to 1709 in 1900. Therefore, either these two drugs are never used, or they are useless, or the Registrar-General's returns are false." It is impossible to understand how Mr. Coleridge could bring himself to write thus. Digitalis has a certain effect on the heart-beat; nitrite of amyl diminishes arterial tension. The Registrar-General's returns for all diseases of the circulation include every sort and kind of organic disease of the valves of the heart; include also pericarditis, aneurism, senile gangrene, embolism, phlebitis, varicose veins, and 35,499 deaths from "other and undefined diseases of heart or circulatory system." RABIES For rabies, Mr. Berdoe praises the "Buisson Bath Treatment for the Prevention and Cure of Hydrophobia." The virtues of this treatment are proclaimed by the Chairman of the Canine Defence League, F. E. Pirkis, Esq., R.N., of Nutfield, Surrey, and it is founded, we are told, _on the simple common-sense principle that if poison is injected into a person's veins the best thing to do is to get it out as quickly as possible_. This sentence, and the reference to Mr. Pirkis for further particulars, and the fact that there is, or was, a Buisson Bath at the "National Anti-vivisection Hospital," bring us to the question, What is the value of the evidence in favour of this treatment? Mr. Berdoe, in his Catechism of Vivisection (1903), gives this evidence at considerable length. _The treatment_, he says, _is simplicity itself. It is merely the use of the vapour bath, which causes a free action of the skin to be set up, this draws the blood to the surface of the body, and so relieves the congestion of the internal organs._ Let us consider this sentence. (1.) Suppose that X---- were bitten by a mad dog, say on March 1st, and on March 8th he took a course of Buisson Baths, for safety's sake. There would be no congestion, at that period, of his internal organs; what would be the good of drawing the blood to the surface of his body? Mr. Pirkis says that there would be poison in his veins; it would be a very subtle poison. How can Mr. Pirkis tell that it is all in his veins and none of it elsewhere? Again, X---- would be feeling perfectly well. How would a vapour-bath get this poison out of his veins? It could not do it by relieving the congestion of his internal organs, for they would not be congested. How would it do it? And how would Mr. Pirkis know when it had done it? (2.) Suppose that X---- were bitten by a mad dog, and, in due time, were seized by hydrophobia. Has Mr. Pirkis ever seen a case of that disease--ever seen a case of hydrophobia? Are they going to tie X---- down, or steam him under chloroform, or what? And how many baths would he want? But there are cases; there is evidence; a "mass of cures in Asia." Let us look at them; and let us divide them into cases of prevention and cases of cure. Let us take, first, the cases of cure. There are five of these. Five, and no more. One is Dr. Buisson; cured by one bath, while he was trying to commit suicide; nothing said about the dog. One is a case at Kischineff, near Odessa, 18 years ago; no evidence is given that the dog was rabid. One is a case at Arlington, New Jersey, 18 years ago; no evidence is given that the dog was rabid. One is the case of Pauline Kiehl; no date; no reference to say where the case is published; no account of her symptoms. And one is a case at the Jaffna Hospital, Ceylon; no date; and nothing said about the dog. Of these five cases, three were a boy, a lad, and a little girl; but their ages are not given. Five cases in 20 years; they hail from all parts of the world, France, Russia, the United States, Ceylon, and France again; three of them happened 18 years ago, or more. And, we may be certain, not one of them is genuine. Spurious hydrophobia, the simulation of the disease out of sheer terror of it, as in Dr. Buisson's case, is well known. Now we come to the cases of prevention. Over 80 of them, we are told; but seven are especially noted. Four in 1895, under the care of Dr. Ganguli of Dinajpur; two in 1896, under the care of Dr. Dass of Narainganj; and one in 1896, Mr. Kotwal of Bassein. Of this "mass of cures in Asia," we all know what would have been said if Pasteur had been in charge of them; that the dogs were not rabid, that the bites were not infected, that the wonder is that the poor deluded victims were not added to Pasteur's hecatomb. Next, what does Mr. Berdoe say of the division of all patients at the Pasteur Institute into classes A, B, and C? Does he admit that a dog is proved to have been rabid, if a minute portion of its nervous tissue, taken from it after death, and put into a rabbit, causes the rabbit to have paralytic rabies? No; there are still two things left for him to say:-- 1. He says, on the authority of the _Veterinary Record_ of ten years ago, that _the death of a rabbit with cerebral symptoms is not a positive indication of death from rabies_. 2. He says that Vulpian discovered that healthy human saliva was poisonous to rabbits, and that it contained a micro-organism which Pasteur had also found in the saliva of a rabid patient. What does this statement prove or disprove? It is twenty-five years old; but Mr. Somerville Wood, not long ago, used it at a debating society with great fervour. Also Mr. Berdoe quotes the late M. Peter, Dr. Lutaud's forerunner; quotes an _obiter dictum_ of Professor Billroth, but without any date; tells us that Pasteur himself, in a letter, referring to one particular case, declared cauterisation to be a sufficient preventive, but does not tell us the date of the letter, or the facts of the case; and quotes a death-rate, but stops at 1890. Of course, any method of treatment, if you ransack its records over a sufficient number of years, will show, now and again, failures or disasters. Take, for instance, those methods of light-treatment, which Mr. Berdoe praises so highly. They have had many failures, and one or two disasters. If they had been discovered by the help of experiments on animals, we might have had a pamphlet from the National Society, _The Roentgen "Cure": its list of Victims_. CERTIFICATE A AND CERTIFICATE B Frequent use has been made of some words spoken by the Home Secretary in Parliament, on July 24th, 1899. He was asked whether he would state what rules were laid down with regard to the granting or signing of certificates dispensing with the use of anæsthetics in experiments on animals; and whether there was any limit to the number of such certificates which one person might sign, or to the number of experiments upon different animals which might be performed by the person holding one such certificate. There can be no doubt as to the meaning of these questions. Certificate A, which is granted only for inoculation experiments or similar proceedings, and never for any serious cutting operation, dispenses wholly with anæsthetics. Certificate B, which is granted for any kind of operation _plus_ observation of the animal after operation, dispenses partly with anæsthetics; that is to say, the operation is done under an anæsthetic, and the subsequent observation of the animal, which is counted as part of the experiment, is made without an anæsthetic. The questions come to this: When the Home Office grants Certificate A, or Certificate B, what precautions does it take against any abuse of these certificates, and what restrictions does it impose on them? The Home Secretary answered: "It is the practice of the Home Office, in addition to the fact that all certificates expire on December 31st of the year in which they are granted, to limit the number, and this is always done in the case of serious experiments in which the use of anæsthetics is wholly or partly dispensed with." The _Times_ says that the Home Secretary said "serious experiments." Mr. Coleridge says that _Hansard_ says that the Home Secretary said "serious operations." We need not doubt that Mr. Coleridge is right; but we may doubt whether Hansard underlines the word _wholly_, as Mr. Coleridge does. Anyhow, it does not matter now whether the Home Secretary, seven years ago, said _experiments_ or _operations_. His meaning is clear enough; that, in all serious procedures, whether they be under Certificate A or under Certificate B, a limit is put to the number of experiments. Which is the plain truth, as everybody knows who is concerned in the administration of the Act; and the limit may be very strict indeed. After this statement by the Home Secretary in 1899, we still find Dr. Abiathar Wall, the Hon. Treasurer of the London Anti-vivisection Society, saying in 1900 that a _vivisector has only to say that he has a theory whereby he hopes to discover a cure for, say, neuralgia of the little finger, and the Home Secretary promptly arms him with a license to torture as diabolically as he pleases and as many animals as he deems fit_. And the National Society has made constant use of this phrase about "serious experiments"; declaring that the Home Secretary himself has said that animals are tortured under the Act. Here are three statements to that effect, made by the National Society's Parliamentary Secretary, by its Lecturer, and by its Hon. Secretary:-- 1. (Annual Meeting, Queen's Hall, May 1900.)--"If you are still unconvinced--if any one is not thoroughly satisfied that there is ample cause for the anti-vivisectionist movement to-day--it is only necessary for me to refer you to the words of the Home Secretary, as spoken in Parliament, in the year 1898.[49] He said: 'There are serious operations which are performed, during which the use of anæsthetics is wholly or partially dispensed with.' Could there be any more sweeping indictment than that? Is there any need for me to attempt to convince you that the lower animals are vivisected painfully, after the words officially spoken by the Home Secretary in the House of Commons?" 2. "If you want any further proof I will quote from Hansard, July 24th, 1899, when the then Home Secretary stated in the House of Commons that serious experiments take place under the law of England, in which the use of anæsthetics is wholly or partially dispensed with. Now, I affirm that serious experiments in which anæsthetics are wholly or partially dispensed with mean torture pure and simple." 3. (Annual Meeting, St. James's Hall, May 1901.)--"If this were not enough, the late Home Secretary has told us the facts. I have Hansard here. On July 24th, 1899, the late Home Secretary in his place in Parliament, and in his official capacity as Home Secretary, told us that 'serious experiments, in which the use of anæsthetics have been wholly or partially dispensed with,' do take place in English laboratories. We know, therefore, that torture does take place." [49] This should be 1899. Each of the three speakers uses this phrase as a final and irresistible argument. _If you are still unconvinced. If you want any further proof. If this were not enough_--they all of them play the Home Secretary, as a sure card: at Queen's Hall, at St. James's Hall, they produce him as though it were indeed unanswerable. Since they are willing to go back to July, let us take them back to May. This phrase about "serious experiments" was spoken on July 24th, 1899. On May 9th of that year, a question was put and answered in the House. It was put by the same gentleman who put the question in July; it was answered by the same Home Secretary; and it was practically the same question. The Home Secretary, in his answer to it, said:-- "The sole use of this Certificate (B) is to authorise the keeping alive of the animal, after the influence of the anæsthetic has passed off, for the purpose of observation and study. I should certainly not allow any certificate involving dissections or painful operations without the fresh use of anæsthetics." Here, in May 1899, we have this emphatic statement, that Certificate B is _not_ allowed for "serious operations without anæsthetics." Why did the National Society stop at July? If it had only gone a few weeks further back, a surprise was in store for it. But at July it stuck; thus it was still able to say all sorts of things about "legalised torture." So late as May 6th, 1902, at the great annual meeting at St. James's Hall, the Rev. Reginald Talbot said:-- "Certificate B makes it necessary that the operator should produce complete anæsthesia during the initial operation, but (please mark this) after the initial operation is over, after the animal has returned to the state of semi or complete consciousness, there is then allowed by this certificate a period of observation upon a semi-sensible or completely sensible animal. The animal is opened, is disembowelled, and in that condition his vital organs can be probed and stimulated. Now that is something more than pain; it deserves something more than the name of even severe and prolonged pain. Surely this comes within the tract and region of what we may call agony." As for Certificate A, the inoculations-certificate, which is used for inoculations only, and therefore is granted for nine experiments out of every ten, he said:-- "There is a Certificate A, which, if it were granted, and when it is granted--and pray you mark my words, for I know what I am speaking about, and I want you to know too--would allow major operations to be performed upon animals, cats, dogs, or any other animals, without the use of any anæsthetic at all. I know quite well that that certificate has not been applied for, or has not been granted this last year, or, so far as I know, in any previous year, but I say this," &c. It is impossible to understand these words. Certificate A is never granted for major operations. It is never granted (save in conjunction with another certificate) for any sort or kind of experiment on a cat or a dog, or a horse, or an ass, or a mule. It is more in use than all the other certificates put together; it covers nine experiments out of every ten. We shall try in vain to guess how this mistake arose in the speaker's mind. But, at the great annual meeting of the chief of all the anti-vivisection societies, it is strange indeed that nobody seems to have corrected him. This description of a certificate which does not exist--_I know what I am speaking about_, he says, _and I want you to know too_--was applauded by an audience that filled the whole hall. Nobody on the platform put him right. And, in the next number of its official journal, the National Society reported every word of his speech, and said that he had _analysed the Act and its administration in a striking and powerful manner_. CURARE "Curare," says Mr. Berdoe, "paralyses the peripheral ends of motor nerves, even when given in very minute doses." That is to say, it prevents all voluntary motion. Then comes this frank admission, "Large doses paralyse the vagus nerve and the ends of sensory nerves." That is to say, it can be pushed, under artificial respiration, till it paralyses sensation. With small doses, the ends of the motor nerves lose touch with the voluntary muscles. With large doses, under artificial respiration, the ends of the sensory nerves lose touch with the brain. Let us agree with Mr. Berdoe that curare does act in this way; that it does not heighten sensation, and has no effect, save in very large doses, on sensation, and then abolishes sensation. Only, of course, to procure this anæsthetic effect, the animal may have to be subjected to artificial respiration. (The evidence as to the action of curare on the sensory nerves rests not on the case of accidental poisoning recorded by Mr. White, though that case does point that way, but on Schiff's experiments on the local exclusion of the poison from one leg of the frog by ligature of an artery.) This, surely, is a true definition of curare, that it is a painless poison, which in small doses prevents the transmission of motor impulses; and, in large doses, which may necessitate the use of artificial respiration, prevents the transmission of sensory impulses. Mr. Berdoe can hardly refuse to accept this definition; indeed, it is his own. And, certainly, he would be a bold man who said that a small dose of curare has any effect on sensation; or that the exact strength of any one specimen of curare is standardised as a supply of antitoxin is standardised. Now we have a perfect right to take a practical view of curare. At the present time, and in our own country, how is it used? The Act forbids its use as an anæsthetic. What evidence does Mr. Berdoe bring that it is so used? 1. He quotes Professor Rutherford's experiments. These were made at least 16 or 17 years ago. 2. He quotes Dr. Porter's paper, "On the Results of Ligation of the Coronary Arteries." (_Journal of Physiology_, vol. xv. 1894, p. 121.) Dr. Porter speaks of four experiments made under morphia _plus_ curare. These experiments were made at Berlin, 14 years ago, by the Professor of Physiology at Harvard, U.S.A. 3. He refers to Professor Stewart's papers, in the same volume of the _Journal of Physiology_. The one experiment which he quotes at some length was made at Strasburg, 14 years ago or more. But we want to know what is done now and here under the Act, not what was done at Berlin or Strasburg 14 or more years ago. Still, the experiments by Professor Stewart have been in constant use, among the opponents of all experiments on animals. In May 1900, at the great annual meeting of the National Society, at Queen's Hall, Dr. Reinhardt said:-- "I will pass on to prove to you, by a few conclusive evidences, for which I can give you chapter and verse, that torture is inflicted on animals by British vivisectors to-day. Now, if you buy the 15th volume of the _Journal of Physiology_, and look at page 86, you will find there," etc. To prove that animals are tortured in England to-day, he quotes one experiment made at Strasburg ever so long ago. And, in 1901, Mr. Coleridge wrote, in the _Morning Leader_, saying: _It is with curare, which paralyses motion and leaves sensation intact, that all the most shocking vivisections are performed._ And, the same year, Mr. Stephen Smith, a "Medical Patron" of the London Society, wrote: _I state emphatically that when curare is used, proper anæsthesia is out of the question...._ _Curare is used daily throughout England. Mention of an anæsthetic in a report is no guarantee that the animal was anæsthetised._ I cannot find, in all the anti-vivisection literature which I have read, any shadow of evidence that any experiment of any sort or kind has been made in this country, on any sort or kind of animal, under curare alone, for the last sixteen or seventeen years. I believe that I might go further back than that. But surely that is far enough. Certainly, so long as any curare is used (not as an anæsthetic, but in conjunction with an anæsthetic) in any experiments on animals in this country, the societies will not trouble to inquire how much of it is used. I wrote, therefore, to the Professors of Physiology at Edinburgh, Cambridge, and Oxford, and asked them to tell me how much curare was used in their laboratories throughout 1903, and what anæsthetics were given with it. Some opponents of experiments on animals seem to think that curare is used very often. One of them says that it is "used daily throughout England." So I wrote to these Professors at our Universities, and they kindly sent the following answers:-- 1. "Your question _re_ curare is easily answered. We did _no_ experiments with it during the past year. Indeed, I have given it up almost entirely for years, chiefly because it is very difficult to get a preparation which--I suppose from impurities--does not seriously affect the heart. There might still be occasions during which it is necessary to use it--if, _e.g._ the _least_ muscular movement would vitiate the results of an experiment. But I find it possible in nearly all cases to get such absolute quiescence with morphia or chloral (besides ether and chloroform) that to all intents and purposes I have long given up the use of curare. Of course, if I had occasion to use it, an anæsthetic would be administered at the same time." 2. "I have asked those who worked in the physiological laboratories in 1903 to give me a return of the number of experiments done and of the number in which curare was used. Including my own experiments, I find that 160 in all were made under the License and Certificates B, EE, C. Curare was given in four cases; in two of these the A.C.E. mixture was the anæsthetic, in the other two ether." 3. At the third laboratory, during 1903, curare was given to seven frogs deprived of their brains before it was given, and to one rabbit under ether. That was the whole use of curare, during a whole year, in three great Universities: at one, seven inanimate frogs, and one rabbit under ether; at another, four animals, under A.C.E. or ether; at another, nothing. INCOMPLETE ANÆSTHESIA It sometimes happens, at an operation, that the patient moves. Mostly, this movement is at the moment of the first incision through the skin; but it may be at some later period during the operation. He does not remember, after the operation, that he moved, or that he felt anything. That is incomplete anæsthesia, or light anæsthesia. The corneal reflex may be abolished, and still the patient may move. Seven years ago some experiments were made in this country by an American surgeon. In the published account of them, it was said that one of the animals was, at one time, under incomplete anæsthesia, and that, in the case of another animal, the anæsthesia was at one time overlooked. This latter phrase meant not that the anæsthetic had been left off, but that it had been given in excess, so that the blood-pressure suddenly fell. The character of the experiments, and the occurrence of these two phrases about the anæsthesia, roused some criticism, and the Home Office instituted an inquiry into the matter. "That inquiry," it said, October 11th, 1899, "resulted in showing no evidence whatever that the animals experimented on by Dr. Crile felt pain. On the contrary, all the evidence shows they did not." The Act does not go into questions of corneal reflex, and unconscious muscular movements, and all the undefinable shades between incomplete anæsthesia and complete anæsthesia and profound anæsthesia. "The only substantial question," says the Home Office, "is whether or no the animal has been during the operation under the influence of an anæsthetic of sufficient power to prevent it feeling pain. This is the requirement of the law." We cannot refuse to call morphia and chloral anæsthetics, for there are deaths every year from an over-dose of them. And we cannot admit that an animal under an anæsthetic, because it makes a movement, is in pain or is conscious; for we know that a patient under operation may move yet feel nothing. Every hospital surgeon, and every anæsthetist, who has seen a whole legion of patients go under chloroform or ether and come out of it, and everybody who has been under these anæsthetics, they all know that incomplete anæsthesia is not "sham anæsthesia," and that movements, even purposive movements, may occur without consciousness, without pain, alike in men and in animals. ONE ANIMAL AND ONE EXPERIMENT When the Home Office allows a licensee to make a certain number of experiments, it means that he may experiment on that number of animals and no more. The Home Office, having heard what the experiments are to be, where they are to be made, on what kind of animals, and for what purpose, and having taken advice about them, allows him to make a fixed number, and adds any restrictions that it likes, _e.g._ that he must send in a preliminary report when he has made half that number. And one thing is certain, that one experiment = one animal, and that 10 experiments = 10 animals, and no more. Everybody knows that, who knows anything at all about the administration of the Act. Now take a false statement, which has been made again and again during many years, that one experiment = any number of animals, and observe how it spread. 1. In the House of Commons, on March 12th, 1897, Mr. MacNeill asked whether any record were kept of the number of animals used in experiments during 1895, and said that 200 or 300 animals are sometimes used in a single experiment, and that 80 or 90 is a common number. The Home Secretary answered: "The honourable member is under an entire misapprehension. The number of animals used does not exceed the number of experiments given in the return." 2. A year later, May 18th, 1898, at the Annual Meeting of the National Society, Mr. MacNeill said again: "Any one casually reading that report (the Inspector's report to Government) would imagine that each experiment was on the body of a single animal. It is nothing of the kind. An experiment is a series of investigations in some particular branch, and sometimes 20, 30, or 40 animals are sacrificed in the one experiment." The National Society published this speech in its official journal. 3. A few weeks later, an anonymous letter in the _Bradford Observer_ said, "Any one casually reading the report would imagine that each experiment was on the body of a single animal. It is nothing of the kind. An experiment is a series of investigations in some particular branch, and sometimes 20, 30, or 40 animals are sacrificed in the one experiment." 4. On August 1st, 1898, the National Society published this letter in its official journal, under the heading, "Our Cause in the Press." 5. On October 21st, 1902, a letter in a provincial paper said that "one experiment" means "not one animal, but a series of operations on many animals." 6. In January 1903, the National Society admitted that its action in 1898 (see 4) was "unfortunate." 7. On June 25, 1903, in Parliament, Mr. MacNeill again said that "an experiment" did not mean one operation, but a series of researches, "often performed by persons who had no more skill than the children who broke up a watch." 8. About this time, the same false statement was made by an Anti-vivisection Society at Manchester. 9. A little later, it was made by the National Canine Defence League, in these words, "Each experiment may include any number of dogs. There is no limit fixed by law." On January 11th, 1904, in the _Times_, the leaflet containing this and other "grossly false and misleading statements" was vehemently denounced by the National Society. It would be hard to find a better instance of the spreading of a false report. An experiment? Oh, it is any number of animals--20 of them, 30 of them; 200, 300 of them; hecatombs, and triple hecatombs; any young doctor can get leave to cut them up. CERTIFICATES E AND EE For all inoculations and similar proceedings, Certificate A is necessary. For all experiments where the animal is allowed to recover from the anæsthetic, Certificate B is necessary. But these certificates do not extend to the dog, the cat, the horse, the mule, or the ass. The three latter animals are also scheduled under Certificate F; the dog and the cat under Certificates E and EE. That is to say, to inoculate a dog, _e.g._ for the study of the preventive treatment against distemper, it is necessary to hold a License, _plus_ Certificate A, _plus_ Certificate E; to operate on a dog, and let him recover, it is necessary to hold a License, _plus_ Certificate B, _plus_ Certificate EE. And it is certain that the Home Office does enforce and emphasise here the spirit of the Act; and that it does guard and restrict and tie up Certificate EE with its own hands. Now let us take an instance, which shows in a very unfavourable light the methods of the National Canine Defence League. Three years ago, certain experiments were made on dogs, for the purpose of finding the best way of resuscitating persons apparently drowned. The Home Secretary was asked whether he knew that certain of these experiments were to be made without anæsthetics; and he answered, "In view of the great importance of the subject in connection with the saving of human life, and of the strong recommendations received in support of the experiments, I have not felt justified in disallowing the certificates." A great outcry was raised against these experiments by the National Anti-vivisection Society and the Canine Defence League. The National Society, in its official journal, August 1903, said that it was now proved, "that in England to-day experiments are performed without anæsthetics which involve inconceivable agony to dogs, and this with the deliberate permission of the Home Secretary." Mr. Coleridge made a public appeal to all humane societies, to go down with all their strength into Kent, on that not far distant day when the Home Secretary would have to face his constituents, and turn him out of Parliament. The Canine Defence League sent two memorials to the Home Office, circulated a petition, and issued leaflets, entitled _A National Scandal_, _Scientific Torture_, _A Peep behind the Scenes_, and so forth. We must consider one of these leaflets at some length; but first let us see what is the truth about these experiments. They were made by the Professor of Physiology at Edinburgh; and he has kindly written to me about them. _In every experiment, except two, the animal was, throughout the whole experiment, under complete anæsthesia with chloroform or ether. In two cases, and in two only, a small preliminary operation, under anæsthesia, having been performed, the animal was allowed to recover from the anæsthetic, or almost to recover from it, and was then and there submerged and drowned, at once and completely, to death; no attempt at resuscitation was made; it became unconscious in a little more than a minute._ In the face of these facts, what is to be said of the outcry raised by the Canine Defence League? They presented two memorials to the Home Secretary: they got up a monster petition with thousands of signatures; and they issued the following leaflet:--- SIGN THE NATION'S PETITION TO PARLIAMENT AGAINST THE DISSECTION OF LIVE DOGS _In Medical Laboratories_ */ 1. Dogs, on account of their docility and obedience to the word of command, are the animals chiefly selected for torture. 2. Thousands of dogs are tortured yearly by licensed experimenters. 3. The total number of experiments performed in 1902 was 14,906, 12,776 of which were without anæsthetics. 4. The Home Secretary stated in Parliament on July 22nd, 1903, that neither the starving of animals to death nor the forced over-feeding of animals were included in these returns. 5. Nor does the number 14,906 give the number of dogs used, for each experiment may include any number of dogs--there is no limit fixed by law. 6. The Home Secretary stated in Parliament on May 11th, 1903, that at one laboratory alone in London 232 dogs were used for vivisectional experiments last year. 7. There are now laboratories scattered over the whole of the United Kingdom. 8. The Home Secretary stated in Parliament on 10th July 1903, that one dog may be used _again_ and _again_ for vivisectional experiment or demonstration--and this without anæsthetics. Think of the condition of the poor dog between each living-dissection. Has not the time come for the nation to rise as one man and say-- "This shall not be"? It is no wonder that even the National Anti-vivisection Society, in a letter to the _Times_, December 11th, 1903, denounced this leaflet. The wonder is, that Mr. Pirkis, R.N., the chairman of the Canine League, tried to defend it. _This deplorable leaflet_, said the National Society: _It contains a series of grossly false and misleading statements._ Let us take it paragraph by paragraph. The first two paragraphs are grossly false. The third suppresses the truth. The fourth is grossly false; the Home Secretary said that neither the starving of animals to death nor the forced over-feeding of animals was included among the experiments _authorised or performed_. Paragraph five is grossly false. So is paragraph six: not one word was said about any experiments, either by the Home Secretary or by anybody else. The entire number of all dogs and cats together, under Certificates A, B, E, and EE, throughout the whole kingdom, that year, was 344. Paragraph eight is grossly false. * * * * * For want of space, it is impossible to consider all the special arguments of the anti-vivisection societies. Of course, among these special arguments, there are a few which have something in them. How could they all of them be utterly false? They go back over thirty years; they are drawn from all parts of the world. This incessant rummaging of medical books and journals, British and foreign; and all this everlasting espionage; the whole elaborate system of a sort of secret service--these methods, year in year out, are bound to find, now and again, a fault somewhere. But I do say, having read and re-read a vast quantity of the publications of these societies, that they are, taken as a whole, a standing disgrace to the cause; that they are tainted through and through with brutal language, imbecile jokes, and innumerable falsehoods; that they have neither the honesty, nor the common decency, which should justify them. Still, here it is that the money goes. There is _money in the business_; there is _milk in the cocoa-nut_; and _twopence more, and up goes the donkey_. These are the phrases used, by the National Anti-vivisection Society, of the bacteriologists, and the men who are working at cancer. But these societies, that spend thousands every year, what have they got to show for it all? They have, with much else of the same kind, the _Zoophilist_. Truly, a fine result; a high-class official journal, the _recognised organ of the anti-vivisection movement in England_. Take, for a final instance, one or two of the things said about anæsthetics. On June 12th, 1897, in the _Echo_, Mr. Berdoe said that certain experiments, involving severe operations, had been made on dogs under morphia and curare. He based this assertion on the account of the experiments in the _Journal of Physiology_. On June 18th, Mr. Weir, in the House of Commons, called attention to this assertion; and the Home Secretary promised to inquire into the matter. On July 18th, Mr. Weir asked whether this inquiry had been made; and the Home Secretary answered:-- "Yes, I have made full inquiry into the allegations contained in the letter and statement which the honourable member forwarded to me, and find that they are absolutely baseless. The experiments referred to were performed on animals under full chloroform anæsthesia; the morphia, to which alone allusion was made in the published account of the experiments, being used in addition. Curare was used, but not as an anæsthetic." It is simple enough. The gentlemen who made the experiments did not know that the National Society buys and ransacks the _Journal of Physiology_; or did not care. But the National Society called this answer a "Fruitless Official Denial"; and Mr. Coleridge sent an "explanatory letter" to the London daily papers, accusing all the experimenters of "amending their published record so as to make it fit in with the Government report." In 1899, the National Society published that sentence, which has already been quoted, about the _Nine Circles_, and the "whiff of chloroform possibly administered." In 1900, it said, "The chloroformists of the physiological laboratories are doubtless common porters, with no technical knowledge of their work." In 1901, it said, "Our readers will remember that Mr. Coleridge has had more than one battle with the Home Office on the question of complete and incomplete anæsthesia. We need hardly say that the victory on each occasion rested with our Honorary Secretary." And again, "By many turns of the anti-vivisection screw we have at last extracted (from the Home Office) the admission that pain is not unknown in the laboratories." In 1902, it said, "The blessed word anæsthesia warns off the profane anti-vivisectionist who would rob the altars of science of their victims." Take later instances. In 1903, we find Mr. Wood saying that _we may be sure the narcosis becomes profound when the inspectors knock at the door of the laboratory_; Dr. Brand, saying that _in all experiments, other than inoculations, it is probable that only a whiff of chloroform is given, to satisfy the experimenter's conscience, and to enable him to make humane statements to the public_; and Mr. Berdoe, saying that _vivisectors, where they use anything except curare, employ sham anæsthetics_. Beside such statements as these, there is the argument from the very rare action of morphia as a stimulant (see _British Medical Journal_, January 14th, 1899); but this argument is not in question. The real argument is, that a man who makes experiments on animals is likely enough to tell lies about them. As Mr. Berdoe says, of a very explicit statement about anæsthetics, made by the late Professor Roy, _It is and must be absolutely untrue_. Read again that sentence about the "whiff of chloroform." The phrase is thirty years old; but, like Sir William Fergusson's evidence in 1875, it is still in use. Or take that one phrase--_where they use anything but curare_. It affords, in six words, a perfect instance of the anti-vivisectionist at his worst. IV. "OUR CAUSE IN PARLIAMENT" Under this heading the official journal of the National Society reports questions asked in Parliament, and the answers given to them. This aspect of the work of the anti-vivisection societies, and the part taken by them in elections, and their plans to amend or abolish the Act, must be noted here. In one year, the National Society spent £888, 13s. 2d. on "purely electoral work." That is a very large sum, when we think of _the grave injury done to the cause of mercy by the deplorable waste of money spent in perfectly_ _unnecessary offices and salaries_. The Society's journal tells us something of this electoral work:-- 1899.--"The Parliamentary League has again been successful in its work at bye-elections. At ---- the two candidates were approached, and both gave more or less satisfactory answers. Sir ----'s reply was thought to be the more satisfactory one, and consequently our supporters gave him their votes. As our readers are aware, he was returned." (In a later number, the _Zoophilist_ hints that "further pressure" may be applied to this gentleman in Parliament.) 1900.--"The efforts of the Society will not be confined to forwarding the interests of any one candidate or any one party. As soon as the names of candidates were announced, Mr. Coleridge issued to all of them a circular letter demanding their views on the vivisection question. The numerous replies which have already arrived, and are still arriving, afford results more gratifying than we for a moment anticipated, and show clearly that we are now recognised throughout Great Britain to be a power that cannot be ignored.... Volunteer workers are also being despatched from headquarters to various places. Readers who have votes or who will help in any way are invited to communicate immediately to the head office, when information about the views of their candidates will be at once sent to them." The London Society also, like the National Society, desires to have a representative in Parliament; and this desire is stated in emphatic words in one of its reports. The general tone of that report has already been noted. It loves big black headlines, NO SURRENDER, THE AWAKENING CHURCHES, A TRUCULENT SCIENCE, THE SINEWS OF WAR, THE APPEAL TO THE PEOPLE. They had better ensure the return of that opponent of vaccination who says that you can bring any member of Parliament to your knees. And, of course, these societies follow the successful candidates on their subsequent careers. "In Parliament," says the London Society, "the Society's work is carried on as occasion permits. Members of Parliament are written to or are personally seen at the House of Commons. Questions are drafted for them to submit to the Home Secretary, and one or more officers of the Society are in constant attendance at the House of Commons when the question of vivisection is likely to be raised." And the National Society says, "In order to stimulate attention (to Mr. Coleridge's Bill) our lecturer has been assiduous in his attendance in the lobby of the House during the present session, and by personal interviews has been able to arouse a good deal of interest in it on both sides of the House." It is evident that "Our Cause in Parliament" is urged with diligence, and is not left to stand or fall according to the unsolicited conscience of what the London Society calls the _average lay member_. Take, for example, the system of drafting questions to be put to the Home Secretary. It may or may not take off the edge of sincerity; anyhow, the question should be drafted with great care. On February 26th, 1900, a question was asked as to certain observations which were alleged to have been made on living animals, but in fact had been made on their organs removed after death. The National Society said of this mistake:-- "We wish our readers to know that the question was not prompted by any communication from our Society, and we think it unfortunate that members of Parliament should be asked to put questions in the House by persons who do not realise that questions based on inaccurate premises can do nothing but harm to our cause. It is hard that the whole anti-vivisection movement should suffer through the carelessness and indolence of those who will neither be at the pains to avoid inaccuracy by their own study and investigation, nor by consulting the National Society's officers." These careless, indolent, inaccurate persons, who think so lightly of the National Society's officers, and draft a question so silly that the whole cause is damaged, bring us back to the point whence we started: the want of unity between the societies, the frequent jarring of one with another. We have still to see something of the dealings of the National Society with Government. It is at its best, doubtless, in the formal letters from Mr. Coleridge to the Home Office; but these, after all, are his own work, and the Society cannot take the credit of them. _Per contra_, we may credit to the Society, and not to Mr. Coleridge, certain threats to Ministers in 1898:-- ... "Should we be so unfortunate as to be left by you without such an open assurance, we shall feel it our duty to employ the strength and resources of this Society in an endeavour to prevent your return to Parliament at the next election. We know of a large and increasing number of your constituents who are ready, in the unfortunate event of your being unable to reassure them as to your attitude in the matter of endowing torture, to place humanity above party politics." ... "This Society will feel it to be its duty to use every means in its power to prevent your return to Parliament at the next election." ... "We beg leave to inform you that at the next election the forces of this Society will be used with the utmost vigour to prevent your return to Parliament. We know of many, and shall no doubt soon secure more of your constituents, pledged to place humanity above party and vote against you on the next occasion that you present yourself." What are we to think of these three letters? The resources of the Society, given with some vague hope of keeping animals out of pain, are to be used for keeping Ministers out of Parliament. Note the bullying tone of the letters. It is the same thing, two years later, at the General Election, with the heckling of candidates: _We are now recognised throughout Great Britain to be a power that cannot be ignored_. A Society that bullies Ministers of State, what will it not do to the average lay member? V. A HISTORICAL PARALLEL It is a long way, from the plain duty to take care of animals, to the arguments and general behaviour of these societies. Of course, we have seen them here from the most unfavourable point of view. From that point of view, apart from any more favourable aspect, they have their parallel in history. The two instances are, in some ways, very unlike: but the parallelism is worthy of note. The historical instance is more than fifty years old: we have what was said, in 1851, against his worst opponents, by a man who had an unpopular cause to defend. Newman, in 1851, gave a set of lectures on _The Present Position of Catholics in England_: and his sayings, some of them, seem apt to our present subject. Take the following examples. Only, here and there, a word is altered, or a phrase left out, that all offence may be avoided:-- ... "We should have cause to congratulate ourselves, though we were able to proceed no further than to persuade our opponents to argue out one point before going on to another. It would be much even to get them to give up what they could not defend, and to promise that they would not return to it. It would be much to succeed in hindering them from making a great deal of an objection till it is refuted, and then suddenly considering it so small that it is not worth withdrawing. It would be much to hinder them from eluding a defeat on one point by digressing upon three or four others, and then presently running back to the first, and then to and fro, to second, third, and fourth, and treating each in turn as if quite a fresh subject on which not a word had yet been said." ... "No evidence against us is too little: no infliction too great. Statement without proof, though inadmissible in every other case, is all fair when we are concerned. An opponent is at liberty to bring a charge against us, and challenge us to refute, not any proof he brings, for he brings none, but his simple assumption or assertion. And perhaps we accept his challenge, and then we find we have to deal with matters so vague or so minute, so general or so particular, that we are at our wits' end to know how to grapple with them." ... "For myself, I never should have been surprised, if, in the course of the last nine months of persecution, some scandal in this or that part of our cause had been brought to light and circulated through the country to our great prejudice. No such calamity has occurred: but oh! what would not our enemies have paid for only one real and live sin to mock us withal. Their fierce and unblushing effort to fix such charges where they were impossible, shows how many eyes were fastened on us all over the country, and how deep and fervent was the aspiration that some among us might turn out to be a brute or a villain." ... "We are dressed up like a scarecrow to gratify, on a large scale, the passions of curiosity, fright, and hatred. Something or other men must fear, men must loathe, men must suspect, even if it be to turn away their minds from their own inward miseries.... A calumny against us first appeared in 1836, it still thrives and flourishes in 1851. I have made inquiries, and I am told I may safely say that in the course of the fifteen years that it has lasted, from 200,000 to 250,000 copies have been put into circulation in America and England. A vast number of copies has been sold at a cheap rate, and given away by persons who ought to have known that it was a mere fiction. I hear rumours concerning some of the distributors, which, from the respect which I wish to entertain towards their names, I do not know how to credit." ... "The perpetual talk against us does not become truer because it is incessant; but it continually deepens the impression, in the minds of those who hear it, that we are impostors. There is no increase of logical cogency; a lie is a lie just as much the tenth time it is told as the first; or rather more, it is ten lies instead of one; but it gains in rhetorical influence.... Thus the meetings and preachings which are ever going on against us on all sides, though they may have no argumentative force whatever, are still immense factories for the creation of prejudice." ... "The Prejudiced Man takes it for granted that we, who differ from him, are universally impostors, tyrants, hypocrites, cowards, and slaves. If he meets with any story against us, on any or no authority, which does but fall in with this notion of us, he eagerly catches at it. Authority goes for nothing; likelihood, as he considers it, does instead of testimony; what he is now told is just what he expected. Perhaps it is a random report, put into circulation merely because it had a chance of succeeding, or thrown like a straw to the wind; perhaps it is a mere publisher's speculation, who thinks that a narrative of horrors will pay well for the printing: it matters not, he is equally convinced of its truth: he knows all about it beforehand; it is just what he always has said; it is the old tale over again a hundred times. Accordingly he buys it by the thousand, and sends it about with all speed in every direction, to his circle of friends and acquaintance, to the newspapers, to the great speakers at public meetings.... Next comes an absolute, explicit, total denial or refutation of the precious calumny, whatever it may be, on unimpeachable authority. The Prejudiced Man simply discredits this denial, and puts it aside, not receiving any impression from it at all, or paying it the slightest attention. This, if he can: if he cannot, if it is urged upon him by some friend, or brought up against him by some opponent, he draws himself up, looks sternly at the objector, and then says the very same thing as before, only with a louder voice and more confident manner. He becomes more intensely and enthusiastically positive, by way of making up for the interruption, of braving the confutation, and of showing the world that nothing whatever in the universe will ever make him think one hair-breadth more favourably than he does think, than he ever has thought, and than his family ever thought before him. About our state of mind, our views of things, our ends and objects, our doctrines, our defence of them, he absolutely refuses to be enlightened.... The most overwhelming refutations of the calumnies brought against us do us no good at all. We were tempted, perhaps, to say to ourselves, 'What _will_ they have to say in answer to this? Now at last the falsehood is put down for ever, it will never show its face again.' Vain hope! Such is the virtue of prejudice--it is ever reproductive; future story-tellers and wonder-mongers, as yet unknown to fame, are below the horizon, and will unfold their tale of horror, each in his day, in long succession." ... "Perhaps it is wrong to compare sin with sin, but I declare to you, the more I think of it, the more intimately does this Prejudice seem to me to corrupt the soul, even beyond those sins which are commonly called more deadly. And why? because it argues so astonishing a want of mere natural charity or love of our kind. They can be considerate in all matters of this life, friendly in social intercourse, charitable to the poor and outcast, merciful towards criminals, nay, kind towards the inferior creation, towards their cows, and horses, and swine; yet, as regards us, who bear the same form, speak the same tongue, breathe the same air, and walk the same streets, ruthless, relentless, believing ill of us, and wishing to believe it. They are tenacious of what they believe, they are impatient of being argued with, they are angry at being contradicted, they are disappointed when a point is cleared up; they had rather that _we_ should be guilty than _they_ mistaken; they have no wish at all we should not be unprincipled rogues and bloodthirsty demons. They are kinder even to their dogs and their cats than to us. Is it not true? can it be denied? is it not portentous? does it not argue an incompleteness or hiatus in the very structure of their moral nature? has not something, in their case, dropped out of the list of natural qualities proper to man?" * * * * * These sentences, many of them, might be used now to describe Anti-vivisection at its lowest level. It might keep a higher level: but we have seen that the literature, arguments, and general methods of the Anti-vivisection Societies fail to do that. The Parliamentary interviewer, the itinerant lecturer, and the letter-writer, are not, after all, of much help to any cause: and surely it is time, after all this waste of huge sums of money, that a Royal Commission should inquire, not only into experiments on animals, but also into Anti-vivisection. INDEX A A, Certificate, 268, 286 _Abolitionist_, the, 302 Absorbable ligature, the, 264 Act 39 & 40 Vict. c. 77, 267-293 Actinomycosis, 246 Adrenalin, 263 Aga Khan, Sir, 179 Air, compressed, 71 Algeria, malaria in, 230 America, diphtheria in, 109; tetanus in, 133, 135; yellow fever in, 232-240 Amoy, plague in, 194 Amyl nitrite, 254; false argument, 345 Anaemia, 71; pernicious, 263 Anæsthesia, grades of, 357; false statements, 366 Anæsthetics, discovery and study of, 55, 256; use under the Act, 281 Anderson, Mr., 190 Andrews, Staff-Surgeon, 263 Anglo-Indians and Anglo-Africans, 228 Animal heat, 68 Animals, protective inoculation of, 89-95, 113; action of drugs on, 255 Annett, Dr., 223 Anopheles and Culex, 214-242 Anthrax, 76, 87-95 Antiseptics, 78-86; use of under the Act, 285 Antitoxins, testing of, 270; false arguments against, 338-342. See also Diphtheria, Tetanus, &c. Anti-vivisection Societies, 297 _sqq._; dissensions, 299-302; expenditure, 304-306, 334, 367; acceptance of all advantages from past discoveries, 307; attitude toward sport, 308; toward doctors and hospitals, 310; literature, 313-324; method of espionage, 327; general arguments, 326-334; special arguments, 335-367; electoral and parliamentary tactics, 367-371 Aphasia, 62 Arguments, anti-vivisection, 326-367 Aristotle, 3, 44, 243 Arloing and Courmont, 100 Artificial respiration, 264 Asellius, 19 Assam-Burmah railway, cholera on, 162 Athens, Pasteur Institute at, 143 Aubertin, 62 B B, Certificate, 268, 349. See also Experiments Baccelli, Prof., 133 Bacteriology, 77 _sqq._; not before the 1875 Commission, 75; the foundation of Lister's work, 85; hardly recognised in the wording of the Act, 267; the cause of more than 90 per cent, of all experiments, 292; false statements, 316, 340 Baginsky, Prof., 105 Bagshawe, Bishop, 329 Bainbridge, Surgeon-General, 169 Baker, Major, 172 Bang, Prof., 99 Bannerman, Major, 173, 175, 178 Barbadoes, filariasis in, 240 Barry, Bishop, 343 Battipaglia-Reggio railway, and malaria, 221 Bazan, Dr., 42 Beaumont, Dr. William, 28 Behring, Prof., 102 Belchier, Mr., 40 Belgaum, plague at, 174 Bell, Sir Charles, 46, 57, 65 Bell, Dr., 88 Belladonna, action of, 255 van Beneden, 244 Berdoe, Mr., 314 _sqq._ Bernard, Claude, 24, 30, 56, 248, 254, 282 Bernard Shaw, Mr., 330 Beveridge, Surgeon, 263 Beyrout, experiments at, 214 Bezoar-stone, the, 252 Bichat, 253 Bilaspur, cholera at, 164 Bircher, Dr., 249 Bird-malaria, 217, 218 Birt, Surgeon-Major, 212 Bloemfontein, typhoid at, 203 Blondlot, 29 Blood, circulation of the, 3-10; blood-pressure, 11-16, 70; collateral circulation, 13 Blood-letting, rational use of, 264 "Blood-poisoning," 84 Board of Agriculture laboratories, 288 Board Hospitals, diphtheria in, 116 Boehmer, 42 Bohn, 37 Böllinger, 246 Bombay, plague in, 170 Bone, growth of, 40, 55; transplantation of, 264 Borelli, 25 Borrel, 168 Bouillard, 62 Brain, localisation of functions, 59-67; not sensitive to touch, 65, 285; false argument against experiments on, 336; surgery of, 337 Brieger, 153 Broca, 59 Brown, Captain Harold, 162 Brown-Séquard, Prof., 56 Bruce, Major, 211 Brunton, Sir T. Lauder, on nitrite of amyl, 254 Buchanan, Major, 219 Buenos Ayres, plague in, 194 Buisson bath, the, 345 Buisson, Dr., 347 Burrows, Mr. Herbert, 329 Busk, Prof., 244 Byculla jail, plague in, 170 C C, Certificate, 284 Cabot, Dr., 210 Cachar tea-gardens, cholera in, 164 Cachexia strumipriva, 247, 249 Cæsalpinus, 4, 6 Caisson disease, 71 Calcutta, cholera inoculations in, 156 Calmette, on plague, 168; on snake venom, 259 Calverley, Dr., 202 Cancer, recent experiments on, 288; mice immunised against, 263; cancer of thyroid gland, 344 Cancer Research Fund, 288 Capillaries, discovery of the, 10 Cappel, Mr. E. K., 181 Carbolic acid, 338 Cardiograph, the, 17 Cardwell, Lord, 267 Carle and Rattone, 128 Carrion, Daniel, death of, 257 Cayley, Surgeon-Colonel, 203 Celsus, 77 Cerebellum, 46 Cerebral localisation, 64-67; false argument, 336 Chamberland, Dr., 90 Chantemesse, on Widal's reaction, 210 Charbon, 86-90; inoculations against, 90-93 Charles II., treatment of his case, 251 Chauveau, 97 Chenai, Dr., 189 Chicago, diphtheria in, 109; tetanus in, 135 Childe, Prof., 183 Children, malaria in native, 225 Choke-damp, 70 Cholera, study of, 152; Haffkine's fluid, 153; results obtained in India, 154-166; in Japan, 167; bacteriology and quarantine, 167 Church Anti-vivisection League, 298, 301 Clinical Society, report on diphtheria, 111; on myxoedema, 248 Cobbold, Prof., 244 Cocain, 269 Cohnheim on inflammation, 78; on tubercle, 97 Coleridge, Mr., 300 _sqq._ Commission on experiments on animals (1875), 76, 267, 298; plague Commission (India), 170; Commissions on malaria, 218; on yellow fever, 232; on tuberculosis, 288 Committee on rabies, 142; on myxoedema, 248 Compensatory action of heart, 69 Congress on tuberculosis, 98, 99; International Medical (London), 253, 321 Cooper, Sir Astley, 248 Corthorn, Dr., 190 County Council laboratories, 287 Cretinism, sporadic, treatment with thyroid extract, 250 Crile, Dr., 358 Cuba, yellow fever in, 237-240 Culex and Anopheles, 214-242 Cumine, Mr. A., 170 Cunninghame-Graham, Mr. R. B., 330 Curare, action of, 282, 353; provision of the Act, 274; facts as to its use, 356; false argument, 355 Curzon, Lord, 169, 195 Cyprus, typhoid in, 206 D Daman, plague in, 171 _Dark Deeds_, 313 Darwin, evidence before the 1875 Commission, 68 Davaine on anthrax, 88; on entozoa, 244 Dax, 62 "Dead" vaccines, 197 Death-rate argument, the, 339 Deaths from experiment on self, 257 Deelfontein, typhoid in, 208 Diabetes, 30-35; pancreatic diabetes, 39 Diapedesis in inflammation, 78 Digestion, 24-29; Pawlow's experiments, 70 Digitalis, study of, 253; false argument, 345 Diphtheria, 102-127; discovery of its antitoxin, 103; early results and reports, 103-116; results at the Board Hospitals, 116-123; Siegert's tables, 123; Woodhead's 1901 report, 124; MacCombie's tables, 126; _preventive_ use of the antitoxin, 105-106; tracheotomy statistics, 104-126; false statements and arguments, 310, 316, 338, 339-342 Distemper, inoculation against, 289 Drafting of questions to be put to the Home Secretary, 369 Drowning, experiments on death by, 361 Drugs, action of, 251-258; lingering influence of magic, 251; revolutionary work of Magendie and Claude Bernard, 252; discovery of _selective_ action, 253; effects of drugs on animals, 255 Duboué, Dr., 138 Dundee, tetanus in mills in, 134 Durbhanga jail, cholera in, 162 Durham, Dr., on Widal's reaction, 210; on yellow fever, 235 Dyson, Major, 166 E E and EE, Certificates, 284-286, 361 Eberlé, 38 Edinburgh Hospital, South Africa, typhoid in, 205 von Eisselsberg, 249 Egypt, typhoid in, 199, 206 "Electoral Work" of anti-vivisection societies, 299, 367 Electricity in medicine, 264 Elephantiasis, 240 Elimination of infection (malaria), 223 Elliot, Dr. Andrew, 208 England, variability of diphtheria in, 105 Equilibration, 56 Erasistratus, 3 Erichsen, Sir John, 78, 267 Excision of wound in tetanus, 136 Experiments on self, 152, 153, 169, 220, 222, 233, 257 Experiments during 1905, report to Government on, 283-293 Experiments without anæsthetics, 268-271, 286, 292, 352; false statements, 322, 352, 363 Experiments under Certificate B, or B + EE, or B + F, 285; prohibition of _subsequent_ infliction of pain, 286, 352; these experiments less than 3 _per cent._ of all experiments, 285; inoculation-experiments about 95 _per cent._ of all experiments, 286 F F, Certificate, 284 Fabricius, 5 Fayrer, Sir Joseph, 259 Fenwick, Dr. W. S., 86 Ferran, Dr., 153 Ferrier's work in cerebral localisation, 63 Filariasis, 240; Dr. Low's report on, 241 Finlay's work on yellow fever, 232 Fischer, 153 Fistula, artificial, 28, 29, 70 Fleas and plague, 332 Flourens, 55 Forman, Major, evidence before Plague Commission, 176 Forster, Mr. W. E., 267 Foster, Sir Michael, 58, 66 Foulerton, Mr. A., 210 Fox, Dr., 250 France, Pasteur Institutes in, 150 Frascatorius, 6, 96 Fraser, Prof., 170, 253, 259 French army, diphtheria in the, 103 Fritsch and Hitzig on cerebral localisation, 65 G Gabritchefski, Dr., 105 Gaffky, Dr., 196 Galen, experiment on the arteries, 3; quoted by Asellius, 19; experiments on the nervous system, 44 Gall and phrenology, 60 Gamaleia, 153 Gamgee, Dr. A., experiments on amyl nitrite, 254 Gastric juice, 24-39 Gaya jail, cholera in, 160 Germany, diphtheria in, 105 Glycogen, 30-35 Gmelin, 27 Goldsmiths' Company, the, 117 Gorgas, Major, on yellow fever, 237 Gowers, Sir William, 63 Graaf, Regnier de, 36 Graham, Dr., 214 Grassi, Prof., experiments on malaria, 221, 257 Greece, rabies in, 143 Gull, Sir William, on myxoedema, 247 H Hadwen, Dr., 323 Haffkine, work on cholera, 153; on plague, 168; experiments on self, 257 Haigh, Rev. H., 184 Haldane, Dr., on respiration, 70 Hales, on blood-pressure, 11 Haller, 82 Hallifax, Mr. C. J., 170 Hamburg, cholera at, 152 du Hamel, on growth of bone, 40 Hamer, Dr., 88 Hankin, Dr., 153 Harley, Dr., on pancreatic diabetes, 39 Harvey, William, 5-9, 20, 335 Harvey, Director General, I.M.S., 169, 171, 191 Hatch, Lieut.-Col., 169 Havana, yellow fever in, 238 Havers, 40 Head, Dr., work on the nervous system, 70 Hebra, 82 Hewett, Mr. J. P., 170 Hewlett, Prof., 102, 238 Hill, Dr. Leonard, 71 Hippocrates, 243 Historical parallel, 371 Hitzig, work on cerebral localisation, 64 Hobday, Prof., 281 Holländer, Dr., 336 Horses immunised against tetanus, 133 Horsley, Sir Victor, 315; on Galen, 44; on cerebral localisation, 65; his work on myxoedema, 248, 249 Houston's estimate, 128 Hubli, plague in, 181 Hughlings Jackson, Dr., 63 Hunter, John, 7, 13, 257 Hunter, Dr. William, on pernicious anæmia, 263 Hutton, Mr., 267 Huxley, Prof., 267, 298 Hydatid disease, 245 Hypodermic use of drugs, 264 I Iceland, echinococcus in, 245 Immunised horses, not in pain, 270 Imperial Yeomanry Hospital, typhoid in, 207 India, cholera in, 153; plague in, 168; typhoid in, 198; malaria in, 216 India Office, experiments made for, 288 Inflammation, study of, 77-79 Ingersoll, Col., 329 Inoculations, scheduled under Certificate A, 269; about 95 _per cent._ of all experiments, 292, 325; presence or absence of pain, 270, 287; made by Government and public bodies, 288, 292; false arguments and statements, 338, 352 Internal secretion, 34, 39, 250 Irregularities under the Act, 288 Israel, Prof., 246 Italy, malaria in, 218 _sqq._ J Jains, the, 168 Japan, cholera in, 167 Jesse, Mr., 298 Jewish community at Aden, plague among, 192 Jute mills, tetanus in, 134 K Kanthack, Prof., on tetanus, 130; on snake venom, 259 Kármán, Dr., 104 Karslake, Sir John, 267 Keelan, Lieut., on plague, 187 Keeping down of the mosquito, 229, 242 Kent County Lunatic Asylum, typhoid at, 197 Khartoum Expedition, typhoid on, 197 Khoja community, plague among, 179 Kirki, plague at, 172 Kitasato, Prof., on diphtheria, 102; on plague, 168 Klebs, Prof., on diphtheria, 102; on typhoid, 196 Klebs-Loeffler bacillus, the, 102 _sqq._ Klein, Prof., on anthrax, 76; on cholera, 153; experiment on self, 257 Koch, Prof., on anthrax, 88; on tubercle, 97, 98; on cholera, 152; on typhoid, 196; on elimination of infection (malaria), 223; experiment on self, 257 Koch's postulates, 76 Kocher, Prof., on myxoedema, 247, 249 Krokiewicz, 133 Krönlein, 104 Kroonstadt, typhoid in, 203 Küchenmeister on entozoa, 244 L Lacteals, the, 19-23 Labbé's proteosoma, 217 Laboratories, not dangerous to public health, 258; used in Government service, 288; inspected and approved, 288 Ladysmith, typhoid in, 201 Laennec, on tubercle, 96 Lagos, malaria in, 224, 228 Lamb, Surg.-Capt., 212 Lambert, Dr., on tetanus, 132 Lanauli, plague at, 172 _Lapis Goæ_, given to Charles II., 252 Laryngeal diphtheria, 114, 120 _sqq._ Laveran, on malaria, 216 Lazear, Dr., death from yellow fever, 235 Leblanc, on risk of rabies, 142 Leffingwell, Dr., on history of anti-vivisection, 297 Lefroy, Mr., 241 Legge, Dr., on industrial anthrax, 88 Leuckart, on trichiniasis, 244 Leumann, Surg.-Capt., his work in Hubli, 181-189 Licenses under the Act, 275-277; number granted, but not used last year, 283 Lister, Lord, his account of his work, 78 Literature, anti-vivisection, 313-324 Liverpool School of Tropical Medicine, 218, 224 Llangattock, Lord, 309 Localisation in central nervous system, 54, 59-67 London Anti-vivisection Society, 302, 323, 334 London School of Tropical Medicine, 220 Loraine, Rev. Nevison, 327 Low, Dr. G. C., on malaria, 220; on filariasis, 240 Lucknow, cholera in, 158 Lutaud, Dr., 317 Lymphatic system, the, 23 Lyons, Major, on plague, 172 M MacCallum, 216 McFadyean, Prof., on tuberculin, 100 MacGarvie Smith, 262 MacGregor, Sir William, on malaria, 224, 228 Mackenzie, Dr. Hector, on myxoedema, 250 Mackenzie, Dr. James, on nerve distribution, 70 MacNeill, Mr., statements in Parliament, 359 Macrae, Surg.-Major, 160 Magendie, on the nerve roots, 52; on selective action of drugs, 252 Magic, lingering late in medicine, 251 Mahratta mills and railway, cholera in, 188, 189 Maidstone, typhoid at, 197, 212 Malaria, 214-231, 242 Malay States, malaria in, 230 Malpighi on the capillaries, 10 Malta fever, 211; possibly milk-borne, 213 Malta, typhoid in, 199 Manometers, 11-18 Manson, Sir Patrick, 128, 213, 216, 227 Mantegazza, 330 Marey, 16 Marsden, Dr., on typhoid, 200 Marshall Hall, his work on reflex action, 53 Martin, Prof. Sidney, on diphtheria, 103; on tetanus, 130 Meat, infection of, 99 _Medical Brief_, the, 316, 338 Medical Journals, the, 297 "Medical Opinions on Vivisection," 321 Meerut, typhoid in, 205 Meister, Joseph, Pasteur's first case, 137 von Mering, 38 Metchnikoff, 78, 153 Mice immunised against cancer, 263, 288 Microscope, before bacteriology, 77 Milk, infection of, 98 Ministers of State, letters to, 370 Minkowski, 38 Monsall Fever Hospital, typhoid in, 200 Mora, plague in, 170 Morphia, a true anæsthetic, 281; exceptional action of, 282 Mosquito, the, 214-242 Mosquito brigades, 230 Mukerji, Surg., 166 Müller, Dr., 258 Municipal laboratories, 287 Murray, Dr. George, on myxoedema, 250 Mursell, Rev. A., 320 Mutilations by farmers and breeders, 293 Myers, Dr. Walter, death from yellow fever, 236 Myxoedema, 247-250; false argument, 344 N Nagpur jail, malaria in, 219 National Anti-vivisection Society, 299 _sqq._ National Canine Defence League, 306, 322, 360, 363 National Society for Prevention of Cruelty to Animals, 304 Negative results, frequent, of inoculations, 287 Negri, Prof., 137 Nervous system, the, 44-67 Netley Hospital, work on typhoid, 196; on Malta fever, 212 New Guinea, malaria in, 225 Newman, Cardinal, 371 Nhatrang, plague in, 194 Nicolaier, on tetanus, 129 Nigeria, malaria in, 225 _Nine Circles_, the, 313 Nocard, Prof., on tetanus in horses, 133 Nott, Surg.-Capt., 155 O Official experiments, 288 Oliver, Dr., 88 Ollier, Prof., 43 One experiment = one animal, 359 Oporto, plague at, 168, 194 Opsonic index, the, 101 Ord, Dr., on myxoedema, 247 "Our Cause in Parliament," 367 "Our Cause in the Press," 310, 311, 360 Owen, Sir Richard, 14 Oxygen, inhalation of, 264 P Pacific Islands, filariasis in the, 240 Pædiatric Society of America, report on diphtheria-antitoxin, 109 Palermo, Pasteur Institute at, 144 Pallas, on entozoa, 244 Pancreas, the, 36; pancreatic diabetes, 39 Paralyses of diphtheria, 114, 116, 125 Paralytic rabies of rabbits, 146 Parasitic diseases, 243 Parasitism, 215 Paré, Ambroise, 167, 252 Paris, diphtheria in, 107 Parkinson, Dr., 86 Parsee community at Daman, plague among, 171 Pasteur, his influence on surgery, 79, 84; work on anthrax, 88; on rouget, 94; on rabies, 137 Pasteur Institutes, 140-151; false argument, 345-348 Pathology and bacteriology, 75-86 Pavy, Dr., on diabetes, 35 Pawlow, Prof., on digestion, 70 Pecha, Nurse, 258 Pecquet, Jehan, discovery of the thoracic duct, 21 Pédiatrie, Société de, 106 Pernicious anæmia, 263 Peter, Dr., 141 Pfeiffer, Dr., 153 Phelps, Lieut.-Gen., 323 Phrenology, 60, 333 Phthisis, 96 Physiology, 3-71, 267 Pirkis, Capt., R.N., 346 Plague, 168-195 Poiseuille's manometer, 15 Pollender, 88 Polli, Prof., 79 Polyvalent serum, 86 Ponfick, 246 Poore, Dr., on anthrax, 89; on tetanus, 129 Portland Hospital, typhoid in, 202 Pottevin, Dr., 145 Powell, Dr. Arthur, 165 Prague, tetanus at, 134 _Prejudiced Man_, the, 373 _Preventive_ use of antitoxin in diphtheria, 104, 106; in tetanus, 133-135 Prochaska, 54 Protection against Anopheles and Culex, 227, 241 Puerperal fever, 79-84 Pyæmia, 78 Q Quarantine and bacteriology, 167 Quesada, 257 Quinine, action of, 231 R Rabies, 137-151; tests in 1905, 288, 291; false argument, 345 Rats and plague, 192, 332 Realdus, 4 Réaumur, work on digestion, 25 Redi, on entozoa, 244 Reed, on yellow fever, 239 Reflex action, 53 Registered places under the Act, 283 Registrar-General, the, 339 Reinhardt, Dr., 355 Rennie, Dr., on snake venom, 263 Report on experiments on animals, 283-293 Respiration, 70 Reverdin, Prof., 247 Richardson, Sir Benjamin Ward, 254 Richmond Hospital, Dublin, typhoid in, 207 Rio, Pasteur Institute at, 144 Roger, on anthrax, 88 Rolland, Gen., 175 Rolleston, Dr. Humphry, 207 Romanes, 66 Ross, Prof. Ronald, 216, 228, 242 Rouget, inoculation against, 94 Roux, Prof., 84, 89, 103, 138 Royal Society for Prevention of Cruelty to Animals, 304 Rudbeck, 23 Ruffer, Dr., 170 Rush for plague-serum in 1899, 193 Russia, diphtheria in, 105 Russell, Sir James, 288 Russell, Dr. Risien, 46 S Salicylic acid, 255 St. Martin, Alexis, 28 Sambon, Dr. G. C., 220 Samoa, filariasis in, 240 Sanarelli, Prof., 234, 315 San Carlos jail, yellow fever in, 234 Sanders, Dr., 253 Sanderson, Sir John Burdon, 32 _Saturday Review_, the, 103 Scarbrugh, Dr., 251 Schiff, Prof., 58, 249 _Securus judicat_, 123 Segregation against malaria, 224 _Selective_ action of drugs, 252 Semmelweis, Ignaz, work on puerperal fever, 79-82 Semon, Sir Felix, 248 Semple, Surg.-Major, 196, 210 Serampur, cholera at, 164 "Serious experiments," 349-353 Sewage, experiments for testing, 288 Sewell, Dr., 263 _Shambles of Science_, the, 313 Siegert's tables of diphtheria, 123 Sierra Leone, malaria in, 226 Simon, Sir John, evidence before 1875 Commission, 76 Simpson, Dr. W. J., on cholera, 155 Skin, diseases of, 250; grafting, 264 Skoda, 82 Sleeping sickness, 264 Smith, Dr. J. W., 203 Smith, Mr. Stephen, 355 Snake venom, 259-263 Society for Prevention of Cruelty to Children, 304 South Africa, typhoid in, 200 _sqq._ South America, yellow fever in, 232 _sqq._ Southwell, Bishop of, 319 Spallanzani, 26 Speech centres, the, 59, 337 Spontaneous generation, 244 Sport, attitude of anti-vivisection societies toward, 308 Sphygmometer, the, 17 Spurious hydrophobia, 347 Stanley, Mr., 42 Starling, Prof., 39, 69 Staten Island, 242 Steenstrup, on entozoa, 244 Sternberg, 128, 231 Stoker, Sir W. T., 291 Stone, Dr., 263 Streptococci, 83 Strophanthus, 255 Strychnine, study of, 253 Subdural inoculations, 133, 138, 271 Suppuration, 84 Swammerdam, 244 Syme, 42, 78 Sympathetic system, 69 T _Tabes mesenterica_, 98 Talbot, Rev. R., 352 Terzi, Signor, experiment on self, 220 Tetanus, 128-136 Tew, Dr., on typhoid, 197 Thane, Mr. G. D., 290 Thompson Yates laboratories, 223 Thoracic duct, the, 21 Thuillier, 89 Thyroid extract, use of, 250; false argument, 344 Tiedemann, 27 Tooth, Dr., 202 Torsion of arteries, 264 Tracheotomy in diphtheria, 114-120 Transfusion of saline fluid, 264 Transplantation of bone, 264 Treves, Sir Frederick, 321 Trichiniasis, 244 Trotter, Mr. W. B. L., 288 Tubercle, 96-101 Tuberculin, 98 Typhoid fever, 196-211 U Umarkhadi jail, plague in, 177 Undhera, plague in, 178 V Valentin, 38 Valisnieri, 25 Valléry Radot, 137 Vaso-motor system, 56, 69 Vaughan, Surg.-Capt., 155 Venesection, 264 Venoms, relative strength of, 260 Veratria, 255 Veterinary operations, 281, 293 Vierordt, 17 Villemin, 96 Virchow, Prof., 75, 245 Virulence, grades of, 89, 139, 260 _Virus fixe_, 139 W Wall, Dr. A., 350 Waller, 78 War Office, experiments for, 288 Washbourn, Dr., 208 Wassermann, 153 West, Lieut. J. W., 209 West Africa, malaria in, 224, 226 Wharton Jones, 77 Widal's reaction, 210, 211 Wilberforce, Archdeacon, 319, 328 Willis, 59 Winburg, typhoid in, 209 Winmarleigh, Lord, 267 Wolff, 246 Wood, Mr. Somerville, 339-344 Woodhead, Prof., 117, 124, 271 Woolsorters' disease, 87 Wright, Sir Almroth, 101, 170, 196 Y Yellow fever, 231-240 Yersin, 169, 194 Z _Zoophilist_, the, 314-320 Zürich, diphtheria in, 104 Transcriber's note: In footnote 18 the sentence "Es müssen vor allen Dingen die Quellen, aus denen der Infections-stoff fliesst, so weit es in menschlichen Macht liegt, verschlossen werden. was changed to read: Es müssen vor allen Dingen die Quellen, aus denen der Infektionsstoff fliesst, so weit es in menschlicher Macht liegt, verschlossen werden." Three overwide tables have been split into two parts. In each the first row of the original table has been repeated in the split off table in order to make the table more readable. These three tables appear in: PART II-EXPERIMENTS IN PATHOLOGY, MATERIA MEDICA, AND THERAPEUTICS. VACCINATION AGAINST CHARBON (FRANCE). _Sheep._ VACCINATION AGAINST CHARBON (FRANCE). _Cattle._ VACCINATION AGAINST ROUGET (FRANCE). 
27748	----	POPULAR LECTURES ON ZOONOMIA, OR THE LAWS OF ANIMAL LIFE, IN HEALTH AND DISEASE. BY THOMAS GARNETT, M.D. MEMBER OF THE ROYAL COLLEGE OF PHYSICIANS, LONDON; OF THE ROYAL IRISH ACADEMY; OF THE ROYAL MEDICAL SOCIETY OF EDINBURGH; HONORARY MEMBER OF THE BOARD OF AGRICULTURE; FELLOW OF THE LINNEAN SOCIETY; MEMBER OF THE MEDICAL SOCIETY, LONDON; AND OF THE LITERARY AND PHILOSOPHICAL SOCIETY OF MANCHESTER: &c. &c. FORMERLY PROFESSOR OF NATURAL PHILOSOPHY AND CHEMISTRY IN THE ROYAL INSTITUTION OF GREAT BRITAIN. LONDON: FROM THE PRESS OF THE ROYAL INSTITUTION OF GREAT BRITAIN: W. SAVAGE, PRINTER. PUBLISHED FOR THE BENEFIT OF THE AUTHOR'S CHILDREN BY HIS EXECUTORS. TO BE HAD OF MR. NICHOLSON, SOHO SQUARE, MR. PRICE, WESTMINSTER LIBRARY, JERMYN STREET, AND OF ALL THE BOOKSELLERS. 1804. [FRONTISPIECE PORTRAIT] THOMAS GARNETT. M.D. L. R. Smith, del. Lenney, sculpt. Published Jan. 1, 1805, by the Executors, for the benefit of his orphan children. ENTERED AT STATIONERS HALL. TO THE RIGHT HONOURABLE, AND HONOURABLE, THE MANAGERS OF THE ROYAL INSTITUTION OF GREAT BRITAIN, THESE LECTURES, COMPOSED BY A MAN, WHO, IN HIS LIFE TIME, WAS HONOURED BY THEIR SELECTION, AS THEIR FIRST LECTURER; AND WHOSE INFANT FAMILY HAVE SINCE EXPERIENCED THEIR BENEVOLENCE AND PROTECTION, ARE, WITH PERMISSION, DEDICATED, BY THE TRUSTEES OF THE SUBSCRIPTION, IN FAVOUR OF THOSE ORPHANS. CONTENTS. THE AUTHOR'S LIFE. His early amusements. His apprenticeship to Mr. Dawson. His studies at Edinburgh. In London. His establishment at Bradford. At Knaresborough. At Harrowgate. His marriage. His lectures at Liverpool. At Manchester. At Warrington. At Lancaster. At Glasgow. His tour in the Highlands. The death of his wife. His engagement in the Royal Institution. His resignation. His establishment in Marlborough Street. His appointment as physician to the Mary-le-bonne Dispensary. His death. LECTURE I, INTRODUCTION. Difficulties and advantages of a popular course of lectures. General view of the human frame. Bones. Muscles. Joints. Powers of the muscles. Brain and Nerves. Senses. Hypothesis of sensation. Galvanism. Distribution of the subjects of the course. LECTURE II, ON RESPIRATION. Air. Trachea. Thorax. Animal heat. Its uniformity. Chemical properties of the air. Combustion. Effects of cold. LECTURE III, ON THE CIRCULATION OF THE BLOOD. Respiration partially voluntary. Heart. Circulation. Pulsation. Hepatic vessels. Action of the arteries. Causes propelling the blood. Varieties of the pulse. Changes of the blood. Harvey's merits. LECTURE IV, ON DIGESTION AND NUTRITION. Necessity of food. Structure of the viscera. Bile. Food of man. Gastric juice. Absorption. Assimilation. Lymphatics. Diseases affecting digestion. Advantages of temperance and exercise. LECTURE V, OF THE SENSES IN GENERAL. Sensation. Attention. Internal senses. Habit. Touch. Skin. Pain. LECTURE VI, ON TASTE AND SMELL. Tongue. Kinds of taste. Diseases of taste. Smell. Mucous membrane. Odours. Smell in animals. Diseases of smell. LECTURE VII, ON SOUND AND HEARING. Production of sound. Medium. Ear. Hearing. Pendulums. Chords. Wind instruments. Tones. Velocity of sound. Music. Echo. Deafness. LECTURE VIII, ON VISION. The eye. Figure. Light. Vision. Accommodation to different distances. Seat of vision. Erect vision. Single vision. Squinting. LECTURE IX, ON THE LAWS OF ANIMAL LIFE. Action of external objects. Excitability. Its laws. Action of light. Of Heat. Of food. Sound. Odours. LECTURE X, ON THE LAWS OF ANIMAL LIFE. General laws. Sleep. Degrees of excitability. Health. Comparison with a furnace. Oxidation. Electricity. Hydrogen. Theory of muscular contraction. LECTURE XI, OF THE NATURE AND CAUSES OF DISEASES. Brown's theory. Sthenic and asthenic diseases. Debility. Sthenic depression of spirits. Scale of excitability. Fallacy of symptoms Effects of cold. Alcohol. Sthenic diseases. LECTURE XII, ON INFLAMMATION AND ASTHENIC DISEASES. Nature of inflammation. Distention of the arteries. Cure of ophthalmias. Asthenic diseases. Cold. Intemperance. Mental exertions. Classes of diseases. Cure. Oxidation. LECTURE XIII, ON THE GOUT. Effects of the gout. Gout not hereditary. Symptoms. Causes. Affections of the stomach. Cure. Use of electricity. Diet. LECTURE XIV, ON NERVOUS COMPLAINTS. Predisposition. Classes. Sthenic kinds. Case of the author. Bad effects of wine. Asthenic kinds. Passions. Direct debility. Treatment. Torpor. Remedies. Exercise and temperance. Conclusion. AN ACCOUNT OF THE LIFE OF THE AUTHOR. DR. GARNETT was born at Casterton, near Kirkby Lonsdale, Westmoreland, on the 21st of April, 1766. During the first fifteen years of his life, he remained with his parents, and was instructed by them in the precepts of the established church of England, from which he drew that scheme of virtue, by which every action of his future life was to be governed. The only school education he received during these early years, was at Barbon, a small village near his native place, to which his father had removed the year after he was born. The school was of so little consequence, that its master changed not less than three times during the space of seven or eight years, and the whole instruction he received, was comprehended in the rudiments of the English grammar, a small portion of Latin, and a little French, together with the general principles of arithmetic. His bodily constitution was from the beginning weak and susceptible; he was unequal to joining in the boisterous amusements of his companions, while from the liveliness of his disposition he could not remain a moment idle. To these circumstances we are, perhaps, to attribute the uncommon progress he made in every branch of knowledge to which he afterwards applied himself. Whilst a schoolboy, the susceptibility of his mind, and a diffidence of character connected with it, caused him to associate very little with his schoolfellows: he dreaded the displeasure of his preceptor, as the greatest misfortune which could befal him The moment he arrived at home, he set about preparing his lesson for the next day; and as soon as this was accomplished, he amused himself by contriving small pieces of mechanism, which he exhibited with conscious satisfaction to his friends. His temper was warm and enthusiastic; whatever came within the narrow circle of his early knowledge he would attempt to imitate. He saw no difficulties before hand, nor was he discouraged when he met with them. At the early age of eleven years, he had somewhere seen a dial and a quadrant, and was able to imitate these instruments, nay, with the assistance of the latter, and the small knowledge of arithmetic and trigonometry, which he had then obtained, he formally marched out with his younger brother, and rudely attempted to measure the height of a mountain behind his father's house. When he was nearly fifteen years of age, he was, at his earnest desire, put apprentice to the celebrated mathematician, Mr. Dawson, of Sedbergh, who was at that time a surgeon and apothecary. This situation was peculiarly advantageous to him, on account of the great mathematical knowledge of his master, by whom he was instructed in the different branches of this science; and, notwithstanding his constant employment in necessary business, his ardent pursuit of professional information, and his extreme youth, in the course of four years, he became well acquainted with mechanics, hydrostatics, optics, and astronomy. He afterwards applied himself with energy to the study of chemistry, and other subjects, with which it was thought expedient that he should be acquainted, previously to attending the medical lectures in the University of Edinburgh. Strongly impressed with a sense of the value of time, he was indefatigable in the pursuit of knowledge: by a concurrence of fortunate circumstances, his talents had become so flexible, that he succeeded almost equally well in every subject to which he applied himself; but of chemistry he was particularly fond, and from this time it became his favourite study. During the four years of his apprenticeship, his conduct was in every respect highly commendable; he was assiduous, he was virtuous. His pursuit after general knowledge was restrained to one object only at a time; he had advanced far in the abstruse sciences; his inclination for study was increased: when in the year 1785, he went to Edinburgh with a degree of scientific knowledge, seldom attained by young men beginning the study of medicine. He became a member of the Medical and Physical Societies, where he soon made himself conspicuous, and of the latter of which, he was afterwards president. Well acquainted with the first principles of natural philosophy, he had considerable advantages over his contemporaries; and his superiority was soon acknowledged. He was not, however, on this account inclined to remit his industry; he attended the lectures of the ablest professors of the day, and more particularly those of Dr. Black, with the most scrupulous punctuality, and endeavoured to elucidate his subject by every collateral information he could obtain. He avoided almost all society; and it is said, he never allowed himself, at this time, more than four hours sleep out of the twenty four. The famous Dr. Brown was then delivering lectures on his new theory of medicine. Dr. Garnett, fired with the enthusiasm of this noted teacher, and struck with the conformity of his theory to the general laws of nature, became one of the most zealous advocates of his doctrine; and from this period, he took, during the remainder of his life, every opportunity of supporting it. During two summers he returned to Mr. Dawson at Sedbergh, passing the intervening winters in Edinburgh: about this time he wrote the essay, which, in the year 1797, he published under the title of a Lecture on Health, which very neatly and perspicuously explains the fundamental parts of the Brunonian theory of medicine: in September 1788, he published his inaugural dissertation de Visu, and obtained the degree of M.D. Very soon afterwards he went to London, to pursue his professional studies, which he continued to do with the greatest perseverance: he attended with unceasing diligence the lectures of the most eminent lecturers, and he sought practical knowledge in the chief hospitals of the metropolis with the most ardent zeal; so that whilst he gained information to himself, he set an impressive example to his contemporary medical students, who in the delusive pursuits of a great city, are too apt to neglect the objects their parents had in view in sending them to the capital. Having finished his studies in London, Dr. Garnett, in 1789, returned to his parents. At the time he left London, he had lost none of his ardour; still he continued indefatigable and observant. He had been flattered and respected by his fellow students, and praised by his seniors; and his previous success animated him with the strongest expectation of future advancement. At this time, it is supposed, he wrote the justly admired Treatise on Optics, which is in the Encyclopaedia Britannica. Soon after his establishment as a physician, at Bradford, in Yorkshire, which took place in the year 1790, he began to give private lectures on philosophy and chemistry. He wrote his treatise on the Horley Green Spa; and in a short time, gained a deserved character of ingenuity and skill as a chemist, a physician, and a benevolent member of society. Bradford did not afford scope for his practice as a physician, equal to the sanguine expectations he had formed; and he was induced to change his situation. In the year 1791, therefore, he removed to Knaresborough, intending to reside at that place during the winter, and at Harrowgate during the summer. This plan he put in execution till the year 1794; his reputation rapidly increased, and his future prospects appeared cheering and bright. He continued to apply himself very closely to chemistry, which was now decidedly his most pleasant and interesting study. He endeavoured to apply his various knowledge to practical purposes, and in many instances was peculiarly successful. No sooner had he arrived at Knaresborough, than anxious to investigate every thing in the neighbourhood, which could at all affect the health of the inhabitants, he began to analyse the Crescent Water at Harrowgate; which he did, with all the accuracy a subject so difficult could admit of; and in 1791, he published his treatise upon it. The same spirit led him, in 1792, to analyse the other mineral waters at the same place of fashionable and general resort, the detail of which he published in the same year. These publications became generally read, and gained him a very extensive reputation. The late Dr. Withering, whose knowledge on these subjects could not be disputed, before he had seen his general analysis of the Harrowgate Waters, said, that "excepting only the few examples given us by Bergman, the analysis of the Crescent Waters was one of the neatest and most satisfactory accounts he had ever read of any mineral water." But his exertions were not confined to professional and scientific pursuits; laudably desirous of advancing knowledge amongst every branch of the community, he formed the plan of a subscription library, which has, since 1791, been of great convenience and utility to the inhabitants of Knaresborough. Far from joining in the opinion which has so much prevailed in modern times, that it was sufficient to aim at general utility, he lost no opportunity of doing good to every member of society. He greatly promoted and encouraged the making of the pleasure grounds and building on the rock, called Fort Montague; and he instructed and assisted the poor man, who is called the Governor, to institute a bank, and to print and issue small bills of the value of a few halfpence, in imitation of the notes of the country bankers, but drawn and signed with a reference of humour to the fort, the flag, the hill, and the cannon. These notes, the nobility and gentry, who during the Harrowgate season crowd to visit this remarkable place, take in exchange for their silver, and by these means the governor, who is a man of gentle and inoffensive manners, has been enabled, with the assistance of his loom, to support himself and a numerous family, and to ameliorate their condition, by giving education to his children. No station in life escaped his benevolent attentions. In order to benefit John Metcalf, who is perhaps more generally known by the name of Blind Jack of Knaresborough, he assisted him to publish an account of the very singular and remarkable occurrences of his life, during a long series of years, under the heavy affliction of total blindness; by the sale of which, this venerable old man derived a considerable contribution towards his subsistence. Whilst at Harrowgate, Dr. Garnett obtained the patronage and protection of the Earl of Rosslyn, then Lord Loughborough, who in the year 1794 built a house for him, which for the future Dr. Garnett meant should be his only residence; it was not long however before he discovered that his situation at Harrowgate was but ill calculated to forward his liberal and extended views. At this place he had small opportunities of attaching himself to his favourite sciences; in the winter months he was without literary society, and it was not for his ardent spirit to remain inactive. About this time also, he formed the idea of going to America, where he thought he might live both honourably and profitably as a teacher of chemistry and natural philosophy. All these circumstances were floating in his mind, when in the year 1794, about the end of July, at the instance of a medical friend, who resided in London, he received as boarders into his house, which was kept by his sister, Miss Catharine Grace Cleveland, daughter of the late Mr. Cleveland, of Salisbury Square, Fleet Street, who was recommended to the use of the Harrowgate waters, together with her friend Miss Worboys. To all who were acquainted with the prepossessing exterior of Dr. Garnett, the liveliness of his conversation, the urbanity of his manners, and his general desire of communicating knowledge to whomever he saw desirous of gaining information, it will be no surprise, that a mutual attachment grew up between him and his inmate, Miss Cleveland, a young lady possessing, in all respects, a mind similar to his own, and who must have felt a natural gratification in the zeal with which the company of the person, on whom she had placed her affections, was sought by all ranks resorting to this fashionable watering place, where every one thought himself most fortunate who sat nearest to him at the table, and where he enlivened the circle around him with his conversation, which was not only instructive, but playfully gay, and entertaining, ever striving to amuse, and always successful in his attempts. The Doctor now began to project plans of happiness, which he had only before held in idea. Previous to his visitors leaving Harrowgate, which was towards the latter end of December, he communicated to Miss Cleveland his intention of going to America. At first she hesitated about accompanying him; but finding his resolution fixed, she at length consented. From this time, till the beginning of March 1795, he continued deliberating upon and maturing his plan. He now departed from Harrowgate, and followed the object of his affection to her mother's residence at Hare Hatch, Berks. He was married to her on the 16th of March, and a fortnight afterwards returned to Harrowgate, to dispose of the lease of his house, and his furniture. Having again joined his wife, he then went to London, where he purchased apparatus for his lectures, and after visiting his parents, he proceeded to Liverpool, in order to obtain a passage to America. Whilst he was thus waiting for the opportunity of a vessel to transport him across the Atlantic, he was solicited by the medical gentlemen at Liverpool, to unpack his apparatus, and give a public course of lectures on chemistry and experimental philosophy. At all times desirous of diffusing the knowledge he had acquired, and eager to fulfil the wishes of his friends, he complied with their request, and entered upon a plan, which in the end completely overturned the scheme he had for several months been contemplating with such ardent hopes of happiness and prosperity. No sooner had he been prevailed upon, than he set about getting every thing ready for his lectures, and after a single week's preparation; he commenced his course. The deep interest he took in his subject, the anxiety he showed to make himself understood, and the enthusiastic hope he constantly expressed of the advancement of science, had a remarkable effect upon his audience; and his lectures were received with the most flattering marks of attention, and excited the most general applause and satisfaction. In a short time, he received a pressing invitation from the most eminent characters at Manchester, to repeat his course in that town. This invitation he accepted, and, encouraged by the success he had just experienced, he postponed the idea of leaving his country. He arrived at Manchester about the middle of January 1796, and began his lectures on the 22nd of that month. Before his arrival, not less than sixty subscribers had put down their names, the more strongly to induce him to comply with their wishes, and many more had promised to do it, as soon as his proposals were published. Notwithstanding he was thus led to expect a large audience, and had procured apartments, which he imagined would be sufficiently spacious for their reception, he was obliged, for want of room, to change them not less than three times during one course. With such success did the career of his philosophical teaching begin, and with such extreme attention and respect was he every where received, that he used afterwards to mention this period, as not only the most profitable, but the most happy of his life. On the 24th of February, his wife was brought to bed of a daughter, the eldest of the two orphans who have now to lament the death of so valuable a parent, to deplore the loss of that independence which his exertions were certain to have raised them, and to rely on a generous public for protection, in testimony of the virtues and merit of their father. After this time Dr. Garnett repeated nearly the same course of lectures at Warrington and at Lancaster; to both which places he was followed by the same success. Whilst he was in this manner exerting himself for the general diffusion of knowledge, his fame spread with the delight and instruction he had every where communicated to his audience. The inhabitants of Birmingham wished to have the advantage of his lectures; and he also received a most pressing invitation from Dublin, where a very large subscription had already been formed. It was his intention to have accepted of the latter invitation, but previous to his departure for Ireland (from whence he had even yet some thoughts of emigrating to America) he was informed of the vacancy of the professorship in Anderson's Institution, at Glasgow, by his friend the late Dr. Easton of Manchester, who strongly urged him to become a candidate. As this situation must inevitably destroy all his future prospects, he for a long time hesitated; but Dr. Easton having informed the Managers of the Institution, that there was a possibility of their obtaining a professor, so eminently qualified as Dr. Garnett, they, after making further inquiry concerning him, offered it to him in so handsome a manner, that, although the situation was by no means likely to be productive of so much emolument as the plan of life he had lately been pursuing, he yielded to their proposal, strengthened as it was by the earnest solicitation of Mrs. Garnett, who felt considerable apprehension at the thoughts of going to America, and consented to accept of the professorship. He began his lectures at Glasgow in November 1796, and a short account of them may be found in his Tour to the Highlands, vol. ii. p. 196. The peculiar clearness with which he was wont to explain the most difficult parts of science, together with the simplicity of the terms he employed, rendered his lectures particularly acceptable to those who had not been initiated in the technical terms, generally used on such occasions. Every thing he delivered might easily be understood by those who had not previously attended to the subject; and of consequence, all who had been disgusted, or frightened by the difficulties they had before met with, or imagined, were eager to receive his instructions; and the audience he obtained, was much more numerous, than either the trustees, or himself, had deemed probable. When the session was completed, he repaired to Liverpool for the purpose of fulfilling a promise he had formerly given to his friends, to repeat his course of lectures in that town. Mrs. Garnett, in the mean time, remained at Kirkby Lonsdale, where he joined her as soon as his lectures were finished. He spent the latter part of the summer chiefly in botanical pursuits, and returned to Glasgow in the autumn, when he made known his intention of practising as a physician. Fortune continued to favour him, his reputation increased, and he rapidly advanced towards the first professional situation in Glasgow. In July 1798, he began his Tour to the Highlands, an account of which he published in 1800, and having returned to his duties in the Institution, the success of his lectures suffered no interruption, but whilst he was reaping the benefit due to his industry and his talents, his happiness received a blow, which was irrecoverable, by the loss of his wife, who died in child birth, December the 25th 1798: the infant was preserved. The sentiments of Dr. Garnett on this occasion will be best expressed in his own words, in a letter to Mr. Ort, of Bury in Lancashire. "Glasgow, January 1st. 1799. "Oh my dear cousin, little did I expect that I should begin the new year with telling you that I am now deprived of all earthly comforts; yes, the dear companion of my studies, the friend of my heart, the partner of my bosom, is now a piece of cold clay. The senseless earth is closed on that form which was so lately animated by every virtue; and whose only wish was to make me happy. "Is there any thing, which can now afford me any consolation? Yes, she is not lost, but gone before: but still it is hard to have all our schemes of happiness wrecked: when our bark was within sight of port, when we were promising ourselves more than common felicity, it struck upon a rock: my only treasure went to the bottom, and I am cast ashore, friendless, and deprived of every comfort. My poor, dear love had been as well as usual during the two or three last months, and even on the dreadful evening (christmas eve) she spoke with pleasure of the approaching event. My spirits were elevated to so uncommon a pitch, by the birth of a lovely daughter, that they were by no means prepared for the succeeding scene; and they have been so overwhelmed, that I sometimes hope it may be a dream, out of which I wish to awake. The little infant is well, and I have called it Catharine, a name which must ever be dear to me, and which I wish to be able to apply to some object whom I love; for though it caused the death of my hopes, it is dear to me, as being the last precious relic of her, whom every body who knew her esteemed, and I loved. I must now bid adieu to every comfort, and live only for the sweet babes. Oh! 'tis hard, very hard. "THOMAS GARNETT." "To Mr. Ort, Bury, Lancashire. The affliction Dr. Garnett experienced on the death of his wife, was never recovered. On all occasions of anxiety which were multiplied upon him, by reason of his exquisite sensibility, he longed for the consolation her society used to afford him; and although his susceptibility to the action of external causes, would not allow him to remain in continued and unalterable gloom and melancholy, yet in solitude, and on the slightest accident, his distress returned, and he despaired of the possibility of ever retrieving his lost happiness. Had it not been for his philosophical pursuits, and the duties of his extensive practice, which kept him almost constantly engaged, it may be doubted, whether he could at this time have sustained the load of sorrow with which he was oppressed. The circumstances which remain to be mentioned are few. From the death of his wife, Dr. Garnett may be considered as unfortunate; for although a fair prospect opened before him, a series of occurrences took place, which neither his state of mind, nor his constitutional firmness enabled him to support. At the time of the formation of the Royal Institution of Great Britain, in London, Count Rumford wrote to Dr. Garnett, to whom he was then an entire stranger, inquiring into the nature and economy of Anderson's Institution, Glasgow; the plan of the lectures given, &c. &c.; and after hinting at the opportunities of acquiring reputation in London, he finally proposed that Dr. Garnett should become lecturer of the new Institution. With this proposal, arduous as was the task, to deliver a course of lectures on almost every branch of human attainment, Dr. Garnett complied, relying on his acquirements, and the tried excellence of his nature; and conscious that no difficulty could resist the indefatigable exertions which on other occasions he had so successfully applied. Flattered by the honour and respect he conceived to be paid to his abilities and qualifications; pleased with the prospect of more rapidly accumulating an independence for himself and his children; and animated with the hope of meeting with more frequent opportunities of gratifying his thirst after knowledge, his spirits were again roused, and he looked forward to new objects of interest in the advancement of his favourite pursuits. In the enthusiasm of the moment, he was known to say, that he considered his connexion with the Royal Institution, from which the country had a right to expect so much, as one of the most fortunate occurrences of his life. On the 15th October 1799, he informed a special meeting of the Managers of Anderson's Institution, of his appointment to the Professorship of Philosophy, Chemistry, and Mechanics, in the Royal Institution of Great Britain, and on that account requested permission to resign his situation. The resignation of a man, whom all loved and revered, was reluctantly, though, as tending to his personal advancement, and the promotion of science, unanimously accepted by the meeting; he was congratulated on his new appointment, and thanked for the unremitting attention he had paid to the interests of Anderson's Institution, ever since he had been connected with it. As an instance of the high esteem in which he was held by the trustees, it may be observed, that his successor, Dr. Birkbeck, was elected by a very great majority of votes, principally on account of his recommendation. In November, he pursued his journey to London, leaving his children at Kirkby Lonsdale, under the care of Miss Worboys. This lady, whose friendship for Mrs. Garnett had induced her to become almost her constant companion, and had even determined her to go with her friend to America, if the Doctor had put his intentions in execution; soon after the death of Mrs. Garnett, had pledged herself, never to desert the children, so long as she could be of any use to them. How faithfully she observes this obligation, all who know her must acknowledge; nor can we, without increased anxiety, reflect upon the situation the poor orphans must have been in without her protection. Dr. Garnett was received by the Managers of the Royal Institution with attention, civility, and respect. During the winter, the lecture room was crowded with persons of the first distinction and fashion, as well as by those who had individually contributed much to the promotion of science; and although the northern accent, which Dr. Garnett still retained in a slight degree, rendered his voice somewhat inharmonious to an audience in London, his modest and unaffected manner of delivering his opinions, his familiar, and at the same time elegant language, rendered him the object of almost universal kindness and approbation. The exertions of the winter had in some measure injured his health, and a degree of uncertainty that he saw in his prospects, tended greatly to depress his spirits. He determined, however, to keep his situation at the Institution, in order that he might at a more convenient time be justified to himself in resigning it. In the summer of 1800, he visited his children in Westmoreland; but his anxiety of mind was not diminished, nor consequently his health improved, by this relaxation from active employment. He walked over the same ground, and viewed the same prospects that he had formerly enjoyed in the company of his wife. He had not resolution to check the impressions as they arose; and thus, instead of being solaced by the beauties which surrounded him, he gave the reins to his melancholy fancy, which, unchecked by any other remembrance, dwelt only on the affection and the virtues of her, whose loss he had ever to deplore; the want of whose society he imagined to be the chief source of his misery. Towards the end of autumn, he returned to the Institution, and in the winter, recommenced his duties as professor. The effect produced upon his lecturing by these and other irritating circumstances was remarkable. Debility of body, as well as uneasiness of mind, incapacitated him for that ardent and energetic pursuit of knowledge, by which he had been so eminently distinguished. His spirited, and at the same time modest method of delivery was changed into one languid and hesitating, that, during this period, occasioned an erroneous judgment to be formed of his abilities as a man of science, and a teacher, by such of his audience as were unacquainted with the cause, or the intrinsic value and merit of the man. At the close of the season, his determination of retiring from the Institution was fixed; and he presented to the Managers his resignation. It was well known to Dr. Garnett's particular friends, that during the early part of this session, he determined to withdraw himself from the Institution; but the success and advancement of the establishment, which he sanguinely hoped would stand unrivalled in the universe, was so intimately connected with the affections of his mind, that he resolved to forego every personal consideration, rather than risk an inconvenience to the Institution, by ceasing to deliver his lectures in the middle of a course; liberally considering, that the Managers, after the business of the season was over, would have time and opportunity before the ensuing session, to fill the professor's chair with talents competent to the arduous undertaking; a circumstance the Managers afterwards so eminently profited by, with the highest credit to themselves, and advantage to the public, in the nomination of the gentlemen who now fill the situation held by Dr. Garnett, and who discharge its important duties with the most distinguished abilities. The transactions of the last winter almost completely served to undermine the small strength of constitution he had left; he was constantly harrassed by complaints in the organs of digestion; head ache deprived him of the power of application; his countenance assumed a sallow complexion; the eye which had beamed with animation, retired within its socket, deprived of lustre; melancholy conceptions filled his imagination more habitually, and were excited by slighter causes; at times, they altogether deprived him of the power of exertion; and while he lamented their effect, the contemplation of themselves rendered him the more their prey. At this time, a gloomy day, or the smallest disappointment, gave him inconceivable distress; but he was not altogether incapable of temporary relief, and the few moments of pleasure he seemed to enjoy, would have given reason to believe, that he might once more have recovered, and have long continued to be the delight and instructor of his friends. A more close observation would at the same time have justified the supposition, that the strong and painful emotions of mind he had suffered, had already induced disorders of the bodily system, which were irrecoverable. Before Doctor Garnett had left his situation at Glasgow, he had determined to practice as a physician in London; but from this he was restrained, during the time he was at the Royal Institution. To his former intention he now determined to apply himself, and in addition to the attempt, by giving private lectures, to assure himself of that independency, of which his unfortunate destiny, though with every reasonable expectation before him, had hitherto deprived him. With this intention, he purchased the lease of a house in Great Marlborough Street; and in the summer of 1801, built a lecture room. He brought his family to town, and once more looked forward with hope. The flattering success he soon met with, and a short residence at Harrowgate in the autumn, contributed to afford a temporary renovation of health and spirits; it was, however, but a short and delusive gleam of prosperity which now dawned upon him; for, confiding too much in his newly increased strength, he exerted himself to a much greater degree than prudence would have suggested. In the course of the following winter, he delivered not less than eight courses of lectures, two on chemistry, two on experimental philosophy, a private course on the same subject, one on mineralogy, and the course to which this sketch is prefixed, which he also delivered in an apartment at Tom's Coffee house, for the convenience of medical students, and others, in the city. Besides these, he commenced two courses on botany, one at Brompton, and the other at his own house; but a return of ill health prevented his concluding them. It was not to be expected, that a constitution so impaired and debilitated, could long support this continued labour of composition and recitation; accordingly he became affected with a consequent disorder, which rapidly exhausted his strength; and, being unable to employ the only probable means of recovering it, he became more incapable of exertion. His spirits however were roused, and he ceased not to use every means of increasing his practice. In the spring of 1802, the office of physician to the St. Mary le Bonne Dispensary happened to be vacant, and he became a candidate; he was more than commonly anxious to obtain this situation. It seemed to him, as if his future good or ill fortune depended altogether upon the event of his canvass, he spared no effort to ensure his success; and accordingly was appointed to the situation in May. His life now drew near a close. Little was he calculated to bear the accumulated labours, and extreme fatigue, to which he was daily exposed. Any benefit which might have resulted from constant and well regulated occupation was frustrated; for whilst he still suffered from the vividness of his conception, representing to him in mournful colours the occurrences of his past life, he became liable to other evils, not less injurious and destructive. The practice of medicine requires both vigorous health of body and firmness of mind. Dr. Garnett, now greatly weakened in body, and not exempt from anxiety of mind, became more and more susceptible to the action of morbific matter. It was not long before he received the contagion of typhous fever, whilst attending a patient, belonging to that very dispensary of which he had been so anxious to become physician. He laboured under the disorder for two or three weeks, and died the 28th of June, 1802; and was buried in the new burial ground of the parish of St. James, Westminster. Thus was lost to society a man, the ornament of his country, and the general friend of humanity. In his personal attachments, he was warm and zealous. In his religion he was sincere, yet liberal to the professors of contrary doctrines. In his political principles, he saw no end, but the general good of mankind; and, conscious of the infirmity of human judgment, he never failed to make allowances for error. As a philosopher, and a man of science, he was candid, ingenuous, and open to conviction; he never dealt in mystery, or pretended to any secret in art; he was always ready in explanation, and desirous of assisting every person willing to acquire knowledge. Virtue was the basis of all his actions; science never possessed a fairer fabric, nor did society ever sustain a greater loss. LECTURES ON ZOONOMIA. LECTURE I. INTRODUCTION. I AM well aware of the difficulties attending the proper composition of a popular course of lectures on the animal economy, which must be essentially different from those generally delivered in the schools of medicine; because it professes to explain the structure and functions of the living body, to those who are supposed to be unacquainted with the usual preliminary and collateral branches of knowledge. It must be obvious to every one, that it can be by no means an easy task to give in a few lectures, a perspicuous view of so extensive a subject; but I trust that the consideration of this difficulty will readily extend to me your indulgence. That such a course, if properly conducted, must be interesting, needs scarcely to be observed; for the more we examine the structure and functions of the human body, the more we admire the excellence of the workmanship, and beauty of contrivance, which presents itself in every part, and which continually shows the hand of omniscience. The most ingenious of human inventions, when compared with the animal frame, indicate a poverty of contrivance which cannot fail to humble the pretensions of the sons of men. Surely then there are few who will not feel a desire to become acquainted with subjects so interesting. But there is another point of view which will place the utility of such inquiries in a still stronger light. We shall afterwards see, that our life is continually supported by the action of a number of substances, by which the body is surrounded, and which are taken into the stomach for its nourishment. On the due action of these depends the pleasant performance of the different functions, or the state of health; without which, riches, honours, and every other gratification, become joyless and insipid. By understanding the manner in which these powers act, or, in other words, by becoming acquainted with the principles of physiology, we shall be enabled to regulate them, so as, in a great measure, to guard against the numerous ills that flesh is heir to: for it is universally agreed, that by far the greatest part of the diseases to which mankind are subject, have been brought on by intemperance, imprudence, and the neglect of precautions, which often arises from carelessness, but much oftener from ignorance of those precautions. Physiological ignorance is, undoubtedly, the most abundant source of our sufferings; every person accustomed to the sick must have heard them deplore their ignorance of the necessary consequences of those practises, by which their health has been destroyed: and when men shall be deeply convinced, that the eternal laws of nature have connected pain and decrepitude with one mode of life, and health and vigour with another, they will avoid the former and adhere to the latter. It is strange, however, to observe that the generality of mankind do not seem to bestow a single thought on the preservation of their health, till it is too late to reap any benefit from their conviction: so that we may say of health, as we do of time, we take no notice of it but by its loss; and feel the value of it when we can no longer think of it but with retrospect and regret. When we take a view of the human frame, and see how admirably each part is contrived for the performance of its different functions, and even for repairing its own injuries, we might at first sight imagine, that such a structure, unless destroyed by external force, should continue for ever in vigour, and in health: and it is by mournful experience alone that we are convinced of the contrary. The strongest constitution, which never experienced the qualms of sickness, or the torture of disease, and which seems to bid defiance to the enemies of health that surround it, is not proof against the attacks of age. Even in the midst of life we are in death; how many of us have contemplated with admiration the graceful motion of the female form; the eye sparkling with intelligence; the countenance enlivened by wit, or animated by feeling: a single instant is sufficient to dispel the charm: often without apparent cause, sensation and motion cease at once; the body loses its warmth, the eyes their lustre, and the lips and cheeks become livid. These, as Cuvier observes, are but preludes to changes still more hideous. The colour passes successively to a blue, a green, and a black; the flesh absorbs moisture, and while one part of it escapes in pestilential exhalations, the remaining part falls down into a putrid liquid mass. In a short time no part of the body remains, but a few earthy and saline principles; its other elements being dispersed through air, or carried off by water, to form new combinations, and afford food for other animals. The human body has been defined to be a machine composed of bones and muscles, with their proper appendages, for the purpose of motion, at the instance of its intelligent principle. From this principle, nerves, or instruments of sensation, are likewise detached to the various parts of the body, for such information as may be necessary to determine it to those motions of the body, which may conduce to the happiness of the former, and the preservation of both. It may perhaps be objected to this definition, that the body consists of other parts besides bones, muscles, and nerves; this is undoubtedly true; but, if we examine more minutely, we shall find that all the other parts, as well as functions of the body, seem only to be subservient to the purposes I have mentioned. For, in the first place, the muscles which are necessary to the motions of the body, are, from the nature of their constitution, subject to continual waste; to repair which waste, some of the other functions have been contrived. Secondly, most of the other parts and functions of the body, are either necessary to the action of the muscles, or to the operation of the intelligent principle, or both. Lastly, from the sensibility, and delicate structure, of the muscles and nerves, they require to be defended from external injuries: this is done by membranes, and other contrivances, fitted for the purpose. To see this more clearly, we shall examine a little more particularly how each of the functions is subservient to the muscular and nervous systems. For this purpose it may be observed, 1st. that the stomach and digestive faculties serve to assimilate the food, or convert it into matter proper to repair the continual waste of solids and fluids. The circulation of the blood besides being absolutely necessary, as we shall afterwards see, to the action of the muscles, distributes the nourishment, thus assimilated and prepared by the stomach, to all parts of the body. The different glands separate liquors from the blood, for useful, but still for subservient purposes. Thus the salivary glands, stomach, pancreas, and liver, separate juices necessary to the proper digestion and assimilation of the food. The kidneys serve to strain off from the blood the useless and superfluous water, salts, &c. which if allowed to remain in the body would be very injurious to it. We shall afterwards see, that the nerves are not only instruments of sensation, but the origin of motion; it being immediately by their means that the muscles are moved. A certain degree of heat is necessary to keep the blood fluid, and also to the action of the nerves; without either of which, no motion could be performed. Respiration or breathing is so necessary to life, that it cannot exist, even a few minutes, without the exercise of that function; and yet we shall afterwards see, that the ultimate end of respiration is to keep the body in a proper state, for the purposes of muscular motion and sensation. The skin serves like a sheath to defend the body from injuries; the skull serves the same purpose to the brain, which is the origin of the nerves. The different membranes separate the fibres, muscles, nerves, and various organs of the body, from each other. Hence we see that there is no impropriety, in calling the human body a machine composed of bones and muscles, with their proper appendages, for the purpose of motion, at the instance of its intelligent principle. In order to show more clearly how each part is subservient to these ends, I shall give a short account of the structure of the human body, but I must premise, that the nature of this course will prevent my entering minutely into anatomical detail. All that can be done is, to give such a general outline of anatomy and physiology, as will furnish individuals with so much knowledge of themselves, as may enable them to guard against habitual sickness. Among the solid parts of the human frame the bones stand conspicuous. Their use is, to give firmness and shape to the body. Some of them likewise serve as armour, or defense, to guard important parts; thus the skull is admirably contrived to defend the brain; and the spine or backbone is designed, not only to strengthen the body, but to shield that continuation of the brain, called the spinal marrow, from whence originate great numbers of nerves, which pass through convenient openings of this bone, and are distributed to various parts of the body. In the structure of this, as well as every other part, the wisdom of the Creator is manifest. Had it been a single bone, the loins must have been inflexible; to avoid which, it consists of a number of small bones, articulated or joined together with great exactness, which are strengthened by compact ligaments. Hence it becomes capable of various inflections, without injuring the nerves, or diminishing that strength which is so much required. The whole system of bones, or skeleton, is constructed of several parts, of different shapes and sizes, joining with one another in various manners, and so knit together, as best to answer to the motions which the occasions of the animal may require. These bones serve as levers for the muscles to act on; which last serve as mechanical powers, to give the machine various motions, at the command of the will. The muscles are fleshy fibres, attached by their extremities to the bones. When the fibres shorten themselves, the two parts into which the muscle is inserted are brought nearer; and, by this simple contrivance, all the motions of animals are performed, and their bodies carried from one place to another. Joints are provided with muscles for performing the motions for which they are adapted; every muscle pulling the bone, to which it is attached, in its own particular direction. Hence the muscles may be considered as so many moving forces, as was before hinted; and their strength, the distance of their insertion from the centre of motion, the length of the lever to which they are attached, and the weight connected with it, determine the duration and velocity of the motions which they produce. Upon these different circumstances depend the different kinds of motion performed by various animals, such as the force of their leap, the extent of their flight, the rapidity of their course, and their address in catching their prey. Most of the muscles act upon the bones, so as to produce the effects of a lever of the third kind, as it is termed by mechanics, where the power acts between the centre of motion and the weight; hence it has a mechanical disadvantage; as an instance of this, the muscle which bends the forearm, is inserted about one eighth or one tenth of the distance from the centre of motion that the hand is, where the weight or resistance is applied; hence the muscle must exert a force eight or ten times greater than the weight to be raised. But this disadvantage is amply compensated by making the limbs move with greater velocity; besides, if room had been given for the muscles to act with greater advantage, the limbs must have been exceedingly deformed and unwieldy. [1] The muscles, in general, at least those which serve for voluntary motion, are balanced by antagonists, by means of which they are kept beyond their natural stretch. When one of two antagonists is contracted by the will, the other relaxes in order to give it play; or at least becomes overpowered by the contraction of the first. Also when one of such muscles happens to be paralytic, the other being no longer balanced, or kept on the stretch, immediately contracts to its natural length, and remains in that situation. The part to which it is fixed will, of course, be affected accordingly. If one of the muscles which move the mouth sideways be destroyed, the other immediately contracting, draws the mouth awry; and in that situation it remains. The same may be observed of the leg, the arm, and other parts. Some muscles assist one another in their action, while others have different actions; according to their shapes, the course of their fibres, and the structure of the parts they move. According to the shape and nature of the bones to be moved, and of the motions to be performed, the muscles are either long, or short; slender, or bulky; straight, or round. Where a great motion is required, as in the leg, or arm, the muscles are long; where a small motion is necessary, they are short; for a strong motion they are thick, and for a weak one slender. Some of the muscles are fastened to, and move bones; others cartilages, and others again other muscles, as may best suit the intention to be answered. With respect to the bones, some are solid and flattened; others hollow and cylindrical. Every cylindrical bone is hollow, or has a cavity containing a great number of cells, filled with an oily marrow. Each of these cells is lined with a fine membrane, which forms the marrow. On this membrane, the blood vessels are spread, which enter the bones obliquely, and generally near their middle; from some branches of these vessels the marrow is secreted; while others enter the internal substance of the bones for their nourishment; and the reason why they enter the bones obliquely is, that they may not weaken them by dividing too many fibres in the same place. The bones being made hollow, their strength is greatly increased without any addition to their weight; for if they had been formed of the same quantity of matter without any cavities, they would have been much weaker; their strength to resist breaking transversely being proportionate to their diameters, as is evident from mechanics. All the bones, excepting so much of the teeth as are out of the sockets, and those parts of other bones which are covered with cartilages, are surrounded by a fine membrane, which on the skull is called pericranium, but in other parts periosteum. This membrane serves for the muscles to slide easily upon, and to hinder them from being lacerated by the hardness and roughness of the bones. But though the apparatus which I have been describing is admirably contrived for the performance of motion; it would continue for ever inactive, if not animated by the nervous system. The brain is the seat of the intelligent principle: from this organ, white, soft, and medullary threads, called nerves, are sent off to different parts of the body: some of them proceed immediately from the brain to their destined places, while the greater number, united together, perforate the skull, and enter the cavity of the backbone, forming what we call the spinal marrow, which may be regarded as a continuation of the brain. Portions of the spinal marrow pass through different apertures to all parts of the body. We are not conscious of the impression of external objects on our body, unless there be a free communication of nerves, between the place where the impression is made and the brain. If a nerve be divided, or have a ligature put round it, sensation is intercepted. There is perhaps only one sense which is common to all classes of animals, and which exists over every part of the surface of the body; I mean the sense of touch. The seat of this sense is in the extremities of the nerves distributed over the skin; and by means of it we ascertain the resistance of bodies, their figure, and their temperature. The other senses have been thought to be only more refined modifications of the sense of touch; and the organs of each are placed near the brain on the external surface of the head. The sense of sight, for instance, is seated in the eye; the hearing in the ear; the smell in the internal membrane of the nose; and the taste in the tongue. The light; the pulses, or vibrations of the air; the effluvia floating in the atmosphere; saline particles, or particles which are soluble in water or saliva, are the substances which act upon these four senses; and the organs which transmit their action to the nerves, are admirably adapted to the respective nature of each. The eye presents to the light a succession of transparent lenses to refract its rays; the ear opposes to the air membranes, fluids, and bones, well fitted to transmit its vibrations; the nostrils, while they afford a passage to the air in its way to the lungs, intercept any odorous particles which it contains, and the tongue is provided with spongy papillae to imbibe the sapid liquors which are the objects of taste. It is by these organs that we become acquainted with what passes around us; by these we know that a material world exists. We may however observe, that the nervous system, besides making us acquainted with external things, gives us notice of many changes that take place within our own body. Internal pain warns us of the presence of disease; and the disagreeable sensations of hunger, thirst, and fatigue, are signs of the body standing in need of refreshment or repose. Concerning the manner in which we become acquainted with external things, by means of the senses, we know nothing. Many hypotheses have been offered to explain this: none of them however are the result of experiment and observation. Many philosophers have supposed the universe to be filled with an extremely subtile fluid, which they have termed ethereal; and this hypothesis has been sanctioned by the illustrious authority of Newton. He however merely offered it in the modest form of a query, for the attention of other philosophers; little thinking that it would be made use of to explain phenomena which they did not understand. His query about a subtile elastic fluid pervading the universe, and giving motion and activity to inert masses of matter, and thereby causing the phenomena of attraction, gravitation, and many other appearances in nature, was immediately laid hold of by his followers, as a fact sufficiently supported, because it seemed to have the sanction of so great an authority. This hypothesis was made use of to explain a great number of phenomena, and the physiologists, whose theories were generally influenced by the prevailing philosophy, eagerly laid hold of it to explain the phenomena of sensation, and muscular motion. When an impression was made upon any part of the external surface of the body, whether it was occasioned by heat, or mechanical impulse, they supposed, that the ether in the extremities of the nerves was set in motion. This motion, from the energy of the ether, is communicated along the nerves to the brain, and there produces such a change as occasions a consciousness of the original impression, and a reference in the mind to the place where it was made. Next they supposed, that the action of the will caused a motion of the ether to be instantly propagated along the nerves that terminate in the fibres of the muscles, which stimulated them to contraction. Other philosophers imagined, that a tremulous motion was excited in the nerves themselves, by the action of external impulses, like the motions excited in the string of a harp. These motions they supposed to be propagated along the nerves of sense, to the brain, and from thence along the motory nerves, to the muscles. Before they attempted this explanation of the phenomena, they should have proved the existence of such a fluid, or at least brought forward such circumstances, as rendered its existence credible. But supposing we grant them the hypothesis, it will, in my opinion, not avail much; for it is not easy to conceive how the motion of a subtile fluid, or the vibration of a nerve, can cause sensation. Nor are the internal senses, as they are generally called, namely, memory, and imagination, any better explained on this supposition; for we cannot conceive how this nervous fluid is stored up and propelled by the will. After all, I think we must confess, that this subject is still enveloped in obscurity. One observation is worth making, namely, that our sensations have not the smallest resemblance to the substance or impression, which causes them; thus the sensation occasioned by the smell of camphor, possesses not the smallest resemblance to small particles of camphor floating in the atmosphere; a sensation of pain has no similitude whatever to the point of a sword which occasions it; nor has the sensation of sound any resemblance to waves or tremors in the air. In our present state of knowledge, therefore, all that we can say, is, that nature has so formed us, that when an impression is made on any of the organs of sense, it causes a sensation, which forces us to believe in the existence of an external object, though we cannot see any connexion between the sensation and the object which produces it. But though philosophers were certainly blameable for assuming an unknown cause, to account for various phenomena, yet later experiments would seem to prove that even the conjectures of Newton were not founded on slight grounds. His idea that the diamond was inflammable, has been confirmed by various experiments: and that there exists in nature a subtile fluid, capable of pervading with ease the densest bodies, the phenomena of electricity would seem to show, and some late experiments render it by no means improbable, that this fluid or influence, acts a conspicuous part in the nervous system. That it exists in great quantity in animal bodies, is evident on gently rubbing the back of a cat in the dark; and it would seem that, in some instances, it may be given out or secreted by the nerves. We shall afterwards see that the seat of vision is a delicate expansion of a large nerve which comes from the brain, and is spread out on the bottom of the eye; and flashes of light, or a kind of sparkling, is often seen to dart from the eyes of persons in high health, and possessed of much nervous energy. These luminous flashes are very apparent in the dark in some animals; such as the lion, the lynx, and the cat; and it is difficult to account for this appearance unless we suppose it electrical. The experiments of Galvani and others, have however proved beyond all doubt, that this fluid, when applied to the nerves and muscles, is capable of exciting various sensations and motions. To produce this fluid by the application of two metals, it is necessary that one of them should be in such a situation, as to be easily oxidable, while the other is prevented from oxidation. If a piece of zinc be put into water, no change will take place; but if a piece of silver be put along with it, the zinc will immediately oxidate, by decomposing the water, and a current of electricity will pass through the silver. If the upper and under surfaces of the tongue be coated with two different metals, one of which is easily oxidable, and these be brought into contact, a sensation is produced resembling taste, which takes place suddenly, like a slight electrical shock. This taste may likewise be produced by applying one part of the metals to the tongue and the other to any part of the body deprived of the cuticle, and bringing them in contact. The sensation of light may be produced in various ways; such as by applying one metal between the gum and the upper lip, and the other under the tongue; or by putting a silver probe up one of the nostrils, and a piece of zinc upon the tongue; a sensation resembling a very strong flash of light is perceived in the corresponding eye, at the instant of contact. But the experiments which tend most strongly to prove what I have hinted, are made in the following manner. Lay bare a portion of a great nerve leading to any muscle or limb of an animal, for instance, the leg of a frog separated from the body. Touch the bared nerve with a piece of zinc, and the muscle with a piece of silver, and strong contractions take place the instant these metals are brought into contact. The same effect may be produced by placing a piece of silver on a larger piece of zinc, and putting a worm or a leech on the silver; in moving about, the instant it touches the zinc it is thrown into strong convulsions. These phenomena have been clearly proved to be electrical; for by a number of pieces of these metals, properly disposed, strong shocks can be given, the electrometer can be affected, a Leyden vial charged, the electric spark seen, and combustible bodies inflamed. Some animals likewise possess the power of accumulating this influence in a great degree; for instanc the torpedo, and electrical eel, which will both give strong shocks; and if the circuit have a small interruption a spark may be seen, as was shown by Mr. Walsh. On dissecting these fish, Mr. Hunter found an organ very similar to the pile of Volta; it consists of numerous membranaceous columns, filled with plates or pellicles, in the form of thin disks, separated from each other by small intervals, which intervals contain a fluid substance; this organ, like the pile of Volta, is capable of giving repeated shocks, even when surrounded by water. It is not absolutely necessary to use two metals to produce the galvanic phenomena; for if one side of a metal be made to oxidate, while the other is prevented from oxidation, these appearances will still be produced. It is not indeed necessary to use any metal; for a piece of charcoal, oxidated in the same way, produces galvanism; so does fresh muscular fibre, and perhaps any substance capable of oxidation. The most striking circumstance in galvanism, is, that it accompanies oxidation, and is perhaps never produced without it. But oxidation is always going on in the body by means of respiration and the circulation of the blood. We shall afterwards find reason to believe, that the oxygen, received from the atmosphere by the lungs, is the cause of animal heat, and probably of animal irritability; and it is perhaps not unreasonable to suppose, that the nervous influence or electricity may be separated by the brain, and sent along the nerves, which seem the most powerful conductors of it, to stimulate the muscles to action. What the nature of the electric fluid is, we are ignorant; some galvanic experiments have led me to suppose that it may be hydrogen, which when combined with caloric appears in the form of gas, but when pure, or perhaps in a different state, may be capable of passing through solid bodies in the form of electricity. Having given this short view of the human body, considered as a machine composed of bones, muscles, and nerves, I shall proceed to state the different subjects which I shall consider in this course. It is extremely difficult to begin a course like this; for we must either enter abruptly into the middle, or the outset must be in some measure tedious and dry. I have chosen however rather to hazard the latter appellation, with respect to this lecture, than to enter more abruptly into the subject, in order to make it more entertaining. As we proceed, I trust you will feel an increasing interest in the subject; and, I think I may venture to promise, that this will be found the least entertaining lecture in the course. The subjects will be illustrated by experiments, in order to render the deductions more striking. I shall next proceed to consider the phenomena of respiration, and animal heat; after which I shall explain the circulation of the blood; and the phenomena of digestion and nutrition. I shall then examine, more minutely than has been done in this lecture, the connexion of man with the external world, which will lead to a discussion of the different senses; vision, hearing, smelling, tasting, and feeling. When these subjects have been discussed as fully as our time will allow, I shall examine, at considerable length, the manner in which the powers that support life, which have been improperly called by physiologists, the nonnaturals, act upon the body. This will naturally lead to a fuller explanation of the system which I have attempted to defend, in my lecture on health. And, after I have fully explained the laws by which the irritable principle is regulated, I shall proceed to show, how those variations from the healthy state, called diseases, are produced; I shall point out the difference that exists between the debility which is brought on by the diminished action of the powers which support life, and that which results from their too powerful action; I shall then inquire into the nature of diseases of increased excitement; and after having shown how the undue action of the powers which support life, operates in producing disease, I shall endeavour to lay down such rules for the preservation of health, as are the result of reasoning on these subjects, and are also confirmed by experience. [1] [FIGURE] Suppose AC to be a lever, held in equilibrio by the force B and weight W, then the whole momentum exerted at B must be equal to that at W, but the forces will be different. For B x AC = W x AB, and if AC = 10AB, then a force equal to ten times the weight to be raised must be exerted by the muscle. Hence we see, that in the actions of muscles there is a loss of power, from their insertions being nearer the fulcrum than the weight. For example, suppose the deltoid muscle to act and raise a weight of 55 lb.: the weight of the arm is 5 lb., and the distance of its insertion is only 1/3 of the arms length, hence the force exerted must be (55 + 5) x 3 = 180 lb. [FIGURE] But by this contrivance we gain a greater extent of motion, and also a greater velocity, and both with less contraction. Let A be the centre of motion, or articulation; B the insertion of a muscle, and AC the length of the lever or bone; then, by a contraction only equal to B_b_, C is carried through C_c_, which is to B_b_ as AC to AB. It is obvious also, that the velocity is greater, since C moves to _c_ in the same time as B to _b_. A loss of power is likewise occasioned by the obliquity of the muscular action, and the oblique direction of the fibres. For, in this case, there is a compound of two forces, and a consequent loss of power: for the forces are proportioned to the two sides of a parallelogram, but the effects produced are proportioned only to the diagonal. LECTURE II. RESPIRATION. In the last lecture I took a short view of the human body, as a moving machine, regulated by the will. We shall now proceed to examine some of its functions more particularly. I need not tell any of my audience, how necessary air is to the living body; for every person knows that we cannot live when excluded from this fluid; but, before we can understand the manner in which it acts on the body, we must become acquainted with some of its properties. That the air is a fluid, consisting of such particles as have little or no cohesion, and which slide easily among each other, and yield to the slightest force, is evident from the ease with which animals breathe it, and move through it. Indeed from its being transparent, and therefore invisible, as well as from its extreme tenuity, and the ease with which bodies move through it, people will scarcely believe that they are living at the bottom of an aerial ocean, like fishes at the bottom of the sea. We become, however, very sensible of it, when it flows rapidly in streams or currents, so as to form what is called a wind, which will sometimes act so violently as to tear up the strongest trees by the roots, and blow down to the ground the best and firmest buildings. Some may still be inclined to ask, what is this air in which we are said to live? We see nothing; we feel nothing; we find ourselves at liberty to move about in any direction, without any hindrance. Whence then comes the assertion, that we are surrounded by a fluid, called air? When we pour water out of a vessel, it appears to be empty; for our senses do not inform us that any thing occupies the place of the water, for instance, when we pour water out of a vial. But this operation is exactly similar to pouring out mercury from a vial in a jar of water, the water gets in and supplies the place of the mercury; so does the air which supplies the place of the water; and this air will prevent water from rising, or filling a vessel which contains it. Hence we see that air possesses similar appearances of impenetrability with other matter: for it excludes bodies from the space which itself occupies. Air being therefore material must have weight; and we shall accordingly find, that a quart of it weighs about fifteen grains. But a quart of water weighs about two pounds; this fluid therefore is nearly a thousand times heavier than air. But though air is so much lighter than water, yet, because it extends to a considerable height above the surface of the earth, it is evident, that it must press strongly on the surfaces of bodies. It is thought to extend nearly fifty miles above the surface of the earth, and must therefore press heavily on this surface. This may be evinced by different experiments, performed by means of the air pump. Another property of the air, by which it is distinguished from most other fluids, is its elasticity. It may be compressed into a less space than it naturally occupies, and when the compressing force is removed, it expands to its former bulk, by its spring or elasticity. Indeed it is always compressed into less space than it would naturally occupy, by the weight of the superincumbent air. The trachea, or windpipe, commences at the further end of the mouth, between the root of the tongue, and the passage into the stomach: its upper part is termed the larynx; it forms the projection in the fore part of the neck, which is more prominent in the male than the female: its opening is called the glottis, and is covered with a small valve, or lid, called the epiglottis, which is open while we breathe, but shuts when we swallow any thing, to prevent its getting into the lungs: sometimes, however, particularly when we attempt to speak at the time we swallow, a small portion of our food or drink gets into the larynx, and excites violent coughing until it is thrown back again. The windpipe is composed of cartilaginous rings, covered with membrane, which keep it open: after having run downwards for the space of a few inches, it divides into two great branches, each of which is subdivided into a vast number of ramifications, ultimately terminating in little vesicles, which, when distended with air, make up the greatest part of the bulk of the lungs. The cavity in which the lungs are contained is called the thorax, or chest: and is bounded by the ribs, and backbone or spine, and separated from the abdomen by a muscular membrane, called the diaphragm. The thorax, by the action of the diaphragm and intercostal muscles, is alternately enlarged and diminished. Suppose then the thorax to be in its least state; if it become larger, a vacuum will be formed, into which the external air will descend by its weight, filling and distending the vesicles of the lungs. The thorax, thus dilated, is brought back to its former magnitude, principally by the relaxation of the muscles, which distended it, and the natural elasticity of the parts, aided by the contraction of the abdominal muscles; the thorax being thus diminished, a quantity of air is expelled from the lungs. The muscles which distend the thorax beginning again to act, the air reenters; and this alternate dilatation and contraction, is called respiration. The entrance of the air into the lungs, is termed inspiration, and its expulsion, expiration. To form a more accurate idea of the manner in which respiration is performed, let us suppose this room to be filled with water. On enlarging the thorax, in the manner before mentioned, the water by its weight would rush in, and fill the newly formed void; and, upon the diminution of the capacity of the thorax, a part of this water would be expelled. Just in the same manner the air will alternately enter and be expelled from the lungs by this alternate dilatation and contraction of the thorax. Respiration is a function of such consequence, that death follows if it is suspended for a few minutes only. By means of this function the blood is elaborated, and rendered fit to nourish the body; by means of it the system is, most probably, supplied with irritability; by means of it the nervous energy is, most likely, conveyed into the body, to be expended in sensation, and muscular motion. It appears, likewise, that in this way, animals are supplied with that heat which preserves their temperatures nearly the same, whatever may be the temperatures of surrounding bodies. If any number of inanimate bodies, possessed of different degrees of heat, be placed near each other, the heat will begin to pass from the hotter bodies to the colder, till there be an equilibrium of temperature. But this is by no means the case with respect to animated matter; for whatever be the degree of heat peculiar to individual animals, they preserve it, nearly unchanged, in every temperature, provided the temperature be not altogether incompatible with life or health. Thus, we find, from experiments that have been made, that the human body is not only capable of supporting, in certain circumstances, without any material change in its temperature, a degree of heat considerably above that at which water boils; but it likewise maintains its usual temperature, whilst the surrounding medium is several degrees below frost. It is evident, therefore, that animals neither receive their heat from the bodies which surround them, nor suffer, from the influence of external circumstances, any material alterations in that heat which is peculiar to their nature. These general facts are confirmed and elucidated by many accurate and well authenticated observations, which show, that the degree of heat in the same genus and species of the more perfect animals, continues uniformly the same, whether they be surrounded by mountains of snow, in the neighbourhood of the pole, or exposed to a vertical sun, in the sultry regions of the torrid zone. This stability and uniformity of animal heat, under such a disparity of external circumstances, and so vast a latitude in the temperature of the ambient air, prove, beyond doubt, that the living body is furnished with a peculiar mechanism, or power of generating, supporting, and regulating its own temperature; and that this is so wisely adapted to the circumstances of its economy, or so dependent upon them, that, whatever be the temperature of the atmosphere, it will have very little influence either in diminishing or increasing that of the animal. In order that we may see how this effect is produced, we must examine the chemical properties of the air. Previously to this, however, it will be necessary to point out briefly how bodies are affected, with respect to heat, when they change their form. When a body passes from a state of solidity to that of fluidity, it absorbs a quantity of heat, which becomes chemically combined with it, and insensible to the touch or the thermometer; in the same manner, when it passes from a fluid state to that of vapour or gas, it combines with a still larger quantity of heat, which remains latent in it, so long as it continues in the state of gas, but when it returns to the liquid or solid state, it gives out the heat which was combined with it, which, being set at liberty, flows into the surrounding bodies, and augments their temperature. This is evinced by the conversion of ice into water, and of water into steam; and by the return of steam into water. It is evinced likewise by the evaporation of ether, and by numberless other experiments. Modern chemistry has shown that the atmosphere is not a homogeneous fluid, but consists of two elastic fluids, endowed with opposite and different properties. If a combustible body, for instance a candle, be confined in a given quantity of atmospheric air, it will burn only for a certain time; after it is extinguished, if another combustible body be lighted and immersed in the same air, it will not burn, but will immediately be extinguished. It has been proved by chemical experiments, that in this instance, the combustible body absorbs that portion of the air which is fitted for combustion, but produces no change on that which is unfit: so that, according to this, the air of the atmosphere consists of two elastic fluids, one of which is capable of supporting combustion, and the other not; and that they exist in the proportion of one part of the former to three of the latter nearly. These two parts may be separated from each other, and experiments made with them. Many metals, and particularly manganese, when exposed to the atmosphere, attract the combustible air from it, without touching the other; and it may be procured from these metals by the application of heat, in very great purity. Because this air is essential to the formation of acids, it has been called by chemists the acidifying principle, or oxygen gas. On plunging a combustible body into the remaining air, it is instantly extinguished; an animal in the same situation is immediately deprived of life: from this latter circumstance this air has been called azote, or azotic gas. If we take three parts of azote and one of oxygen, and mix them together, we shall form an air in every respect similar to that of the atmosphere. If I plunge a piece of iron, previously heated, into oxygen gas, it will burn with great brilliancy, the gas will be diminished in quantity, and the iron augmented in weight, and this increase of weight in the metal will be in proportion to the oxygen which has disappeared: at the same time a great quantity of heat is given out. This is the heat which was combined with the oxygen in the state of gas, and which now becomes free, when the oxygen becomes solid and joins with the iron. The same phenomena take place when phosphorus is burned in oxygen gas; the gas becomes diminished, the phosphorus increased, in weight, and converted into an acid, and a great quantity of heat is given out. The same is the case when charcoal is burned in this gas. In short, in every instance of combustion, the oxygen combines with the combustible body, and at the same time gives out its heat, which supported it in the form of gas. This is the case of the combustion of coal in a common fire, as well as in other cases of combustion; the heat comes from the air, and not from the coal. When we examine the phenomena of respiration with attention, we shall find them very analogous to those of combustion. A candle will not burn in an exhausted receiver: an animal in the same situation ceases to live. When a candle is confined in a given quantity of atmospheric air, it will burn only for a certain length of time. On examining the air in which it has been burned, the oxygen is found to be all extracted, nothing remaining but azotic gas, and a quantity of carbonic acid gas, produced by the union of the charcoal of the candle with the oxygen of the atmospheric air. In the same manner, if an animal be confined in a given quantity of atmospheric air, it will live only a short time; on examining the air in which it has ceased to live, it will be found to have lost its oxygen: what remains being a mixture of azotic and carbonic acid gases. When a candle is enclosed in a given quantity of pure oxygen gas, it will burn four times as long as in the same quantity of atmospheric air. In the same manner it has been proved, that an animal will be four times as long in consuming a given quantity of pure oxygen gas, as in rendering unfit for respiration the same quantity of atmospheric air. Here then we observe a striking similarity between combustion and animal respiration. The ancients seem to have had a more accurate idea of respiration than most of the philosophers who followed them. They supposed that the air contained a principle proper for the support and nourishment of life, which they called pabulum vitae. This idea, which was unconnected with any hypothesis, was followed by systems destitute of foundation. Sometimes it was thought that the air in the lungs incessantly acted as a stimulus or spur to drive on the circulation; sometimes the lungs were considered in the light of a pair of bellows, or fan, to cool the body, which was supposed to be heated by a thousand imaginary causes: and when philosophers were convinced, by experiments, that the bulk of the air was diminished by respiration, they explained it by saying, that the air had lost its spring. Modern chemistry however enables us to explain the phenomena of respiration in a satisfactory manner. In order to see this, we shall proceed to examine the changes produced by respiration; firstly, on the air, and secondly, on the blood. The air which has served for respiration, is found to contain a mixture of azotic and carbonic acid gas, with a small quantity of oxygen gas; and a considerable quantity of water is thrown off from the lungs, in the form of vapour, during respiration. From a variety of facts, it appears that oxygen gas is decomposed in the lungs during respiration; a part of it unites, as we shall afterwards see, with the iron contained in the blood, and converts it into an oxid; another and greater portion unites with the carbon, brought by the venous blood from all parts of the body to the lungs, and thus forms carbonic acid gas; while another portion of the oxygen unites with the hydrogen, brought in the same manner by the blood, and forms water. Thus then we are able to account for the different products of respiration. Hence we see, that the explanation of animal heat follows as a simple and beautiful corollary from the theory of combustion; and we may consider respiration as an operation in which oxygen gas is continually passing from the gaseous to the concrete state; it will therefore give out at every instant the heat which it held in combination, and this heat, being conveyed by the circulation of the blood to all parts of the body, is a constant source of heat to the animal. These facts likewise enable us to explain the reason, why an animal preserves the same temperature, notwithstanding the various changes which occur in the temperature of the surrounding atmosphere. In winter the air is condensed by the cold, the lungs therefore receive a greater quantity of oxygen in the same bulk, and the heat extricated will be proportionally increased. In summer, on the contrary, the air being rarefied by the heat, a less quantity of oxygen will be received by the lungs during each inspiration, and consequently the heat which is extricated must be less. For the same reason, in northern latitudes, the heat extricated by respiration will be much greater than in the southern. By this simple and beautiful contrivance, nature has moderated the extremes of climate, and enabled the human body to bear vicissitudes which would otherwise destroy it. Of all the phenomena of the animal body, there is none at first sight more remarkable, than that which animals possess of resisting the extremes of temperature. The heat of the body, as has already been observed, continues at the same degree, though the temperature of the atmosphere be sometimes considerably hotter, at other times considerably colder, than the animal body: so that man is able to live, and to preserve the temperature of health, on the burning sands of Africa, and on the frozen plains of Siberia. The alterations of temperature which the human body has been known to bear, without any fatal or even bad effects, are not less than 400 degrees or 500 degrees of Fahrenheit. The natural heat of the human body is 96 degrees or 97 degrees. In the West Indies, the heat of the atmosphere is often 98 degrees or 99 degrees, and sometimes rises even to 126 degrees, or 30 degrees above the temperature of the human body, notwithstanding which, a thermometer put in the mouth points to 96 degrees or 97 degrees. The inhabitants of the hot regions of Surinam support, without inconvenience, the heat of their climate. We are assured that in Senegal, about the latitude of 17 degrees, the thermometer in the shade generally stands at 108 degrees, without any fatal effects to men or animals. The Russians often live in places heated by stoves to 108 degrees or 109 degrees, and some philosophers in this country, by way of experiment, remained a considerable time in a room heated above the boiling point of water. On the other hand, an equal excess of cold seems to have no greater effect in altering the degree of heat proper to animal bodies. Delisle has observed a cold in Siberia 70 degrees below the zero of Fahrenheit's scale, notwithstanding which animals lived. Gmelin has seen the inhabitants of Jeniseisk under the 58th degree of northern latitude, sustaining a degree of cold, which in January became so severe, that the spirit in the thermometer was 126 degrees below the freezing point. Professor Pallas in Siberia, and our countrymen at Hudson's Bay, have experienced a degree of cold almost equal to this. All these facts tend to prove, that the heat of animals continues without alteration in very different temperatures. Hence it is evident that they must be able to produce a greater degree of heat, when surrounded by a cold medium; and on the contrary, that they must effect a diminution of the heat, when the surrounding medium is very hot. All these circumstances may be accounted for, by the principles we have laid down; the decomposition of oxygen in the lungs. There have not been wanting, however, some very eminent physiologists, who have contended that animal heat is produced chiefly by the nerves. They have brought forward in proof of this the well known fact, that when the spinal marrow is injured, the temperature of the body generally becomes diminished; and that in a paralytic limb the heat is less than ordinary, though the strength and velocity of the pulse remain the same. These facts, and others of a similar nature, have induced them to believe, that the nervous system is the chief cause and essential organ of heat; and they have adduced similar arguments, to prove that nutrition is performed by the nerves, for a limb which is paralytic from an injury of the nerves, wastes, though the circulation continues. The truth is, that the nerves exert their influence upon these, and all other functions of the body, and modify their action. The liver secretes bile, but if the nerves leading to it be destroyed, the secretion of bile will cease; but who will say, that the bile is secreted by the nerves? The nitric acid will dissolve metals, and this solution will go on more quickly if heat be applied; but surely the nitric acid is the solvent, the heat being only an aiding cause. But though the human body has been so wisely constructed, as to bear, without inconvenience, a considerable variation of temperature; yet this latitude has its limits, which depend upon the capability of extricating heat from the atmosphere. There must be a limit below which the diminution of heat takes place faster than its production. If this be continued, or increased, the heat of the animal must diminish, the functions lose their energy, and an insuperable inclination to sleep is felt, in which if the sufferer indulge, he will be sure to wake no more. This is confirmed by what happened to Sir Joseph Banks and his party on the heights of Terra del Fuego. Dr. Solander, who had more than once crossed the mountains which divide Sweden from Norway, well knew that extreme cold produces an irresistible torpor and sleepiness, he therefore conjured the company to keep always in motion, whatever exertion it might require, and however great might be their inclination to rest. Whoever sits down, says he, will sleep; and whoever sleeps will wake no more. Thus, at once admonished and alarmed, they set forward; but, while they were still upon the naked rocks, the cold was so intense, as to produce the effects which had been so much dreaded. Dr. Solander himself was the first who found the inclination against which he had warned others, irresistible; and insisted on being suffered to lie down. Sir Joseph entreated and remonstrated in vain; he lay down upon the ground, though it was covered with snow; and it was with great difficulty that his friend kept him from sleeping. One of his black servants also began to linger, having suffered from the cold in the same manner as the Doctor. Partly by persuasion, and partly by force, they were got forwards; soon however they both declared that they would go no further. Sir Joseph had recourse again to entreaty and expostulation, but these produced no effect: when the black was told, that if he did not go on, he would shortly be frozen to death; he answered, that he desired nothing so much as to lie down and die. The Doctor did not so explicitly renounce his life, but said, he would go on, if they would first allow him to take some sleep, though he had before told them, that to sleep was to perish. They both in a few minutes fell into a profound sleep, and after five minutes Sir Joseph Banks happily succeeded in waking Dr. Solander, who had almost lost the use of his limbs; the muscles were so shrunk, that his shoes fell from his feet; but every attempt to recal the unfortunate black to life proved unsuccessful. As the circulation of the blood is the means by which the heat produced is conveyed to all parts of the body; and as it is a function of the highest importance, I shall, in the next lecture, proceed to the consideration of it. LECTURE III. CIRCULATION OF THE BLOOD. Two kinds of motion may be distinguished in the animal economy; the one voluntary, or under the command of the will, which takes place at certain intervals, but may be stopped at pleasure. The other kind of motion is called involuntary, as not depending on the will, but going on constantly, without interruption, both when we sleep and when we wake. Of the first kind is the motion of the limbs, of which I have already spoken in general terms; the object of which is, to change the situation of the animal, and carry it where the will directs. Among the involuntary motions, the most remarkable is the circulation of the blood, which I shall proceed to consider in this lecture. There is one motion, however, which claims a middle place between the voluntary and involuntary; I mean respiration. This action is so far under the command of the will, that it may be suspended, increased, or diminished in strength and frequency: but we can only suspend it for a very short time; and it goes on regularly during sleep, and in general, even when we are awake, without the intervention of the will; its continuation being always necessary, as we have already seen, to support life. The motion of the fluids in the living body is regulated by very different laws, from those which govern the motion of ordinary fluids, that depend upon their gravity and fluidity: these last have a general centre of gravitation to which they incessantly tend. Their motion is from above downwards, when not prevented by any obstacles; and when they meet with obstruction, they either stop till the obstacle is removed, or escape where they find the least resistance. When they have reached the lowest situations, they remain at rest, unless acted upon by some internal impulse, which again puts them in motion. But the motion of the fluids in an animal body, is less uniform, constant, and regular; it takes place upwards as well as downwards, and overcomes numerous obstacles; it carries the blood from the interior parts of the body to the surface, and from the surface back again to the internal parts; it forces it from the left side of the body to the right, and with such rapidity that not a particle of the fluid remains an instant in the same place. The principal organ concerned in the circulation of the blood, is the heart; which is a hollow muscle, of a conical figure, with two cavities, called ventricles; this organ is situated in the thorax or chest; its apex or point is inclined downwards and to the left side, where it is received in a cavity of the left lobe of the lungs. At the basis of the heart on each side are situated two cavities, called auricles, to receive the blood; and these contracting, force the blood into the ventricles, which are two cavities in the heart, separated from each other by a strong muscular partition. The cavity which is situated on the right side of the heart, is called the right ventricle, and that on the left the left ventricle. From the right ventricle of the heart issues a large artery, called the pulmonary artery, which goes to the lungs, and is there divided and subdivided into a vast number of branches, the extremities of which are too small to be visible. These ultimate ramifications unite again into larger branches; these again into branches still larger, and so continually, till at last they form four tubes, called the pulmonary veins, which are inserted into the left auricle of the heart, From the left ventricle of the heart there issues another large artery, called the aorta, which, in its passage, sends off branches to the heart, arms, legs, head, and every other part of the body. These branches, in the course of their progress, are divided and subdivided into innumerable minute ramifications, the last of which are invisible. These small ramifications unite again into branches continually larger and larger, till they form two great tubes, called the venae cavae; which large veins are inserted into the right auricle of the heart; where a vein, termed the coronary vein of the heart, which returns the blood from the heart itself, also terminates. From what has been said, it will be evident, that strictly speaking, there are only two arteries and seven veins in the body; one pulmonary artery, which carries the blood from the right ventricle of the heart to the lungs, and four pulmonary veins, which bring it back again; then the aorta or large artery, which carries the blood from the left ventricle of the heart to all parts of the body; the two venae cavae, and the coronary vein of the heart, which bring it back again. At the beginning of both arteries, where they leave the heart, are placed valves, which allow the blood to flow freely from the heart into the arteries, but which prevent its return to the heart. There are likewise valves between the auricles and ventricles, which permit the blood to flow from the former into the latter, but prevent its return into the auricles. The veins are likewise furnished with valves, which allow the blood to flow from their minute branches along the larger toward the heart, but prevent its returning to these minute branches. The blood being brought back from all parts of the body into the right auricle of the heart, distends this cavity, and thus causes it to contract; this auricle, by contracting, forces the blood into the right ventricle; this muscular cavity being distended and irritated by the blood, contracts, and propels the blood through the pulmonary artery into the lungs: from hence it is brought back by the pulmonary veins, to the left auricle of the heart, by whose contraction it is forced into the left ventricle. The contraction of this ventricle propels the blood, with great force, into the aorta, through the innumerable ramifications of which, it is carried to every part of the body, and brought back by veins, which accompany these arterial ramifications, and form the venae cavae, which conduct the blood into the right auricle of the heart, from whence it is again sent into the right ventricle, which sends it through the pulmonary artery, to the lungs; the pulmonary veins bring it back again to the heart, from whence it is propelled through the aorta, to all parts of the body: thus running a perpetual round, called the circulation of the blood. Thus then we see, that the circulation consists of two circles or stages, one through the lungs, which may be called the pulmonary, or lesser circle, and the other through all parts of the body, which may be termed the aortal, or greater circle. That the blood circulates in this manner, is evident, from the valves placed at the origin of the arteries, and in the large branches of the veins, which prevent the return of the blood to the heart, in any other manner than that I have described. This is likewise evident, in the common operation of blood letting: when the arm is tied, the vein swells below the ligature, instead of above, and we do not make the opening above the ligature, or on the side next the heart. If the vein were opened above the ligature, it would not bleed. For it only swells next the hand, which shows that the blood does not flow into the vein downwards from the heart, but upwards from the hand. If the ligature be too tight, the blood will not flow through the opening in the vein. The reason of this, is, that the artery is compressed, in this case, as well as the vein; and as the veins derive their blood from the arteries, it follows that if the blood's motion be obstructed in the latter, none can flow from them into the former: when we wish to open an artery, the orifice must be made above the ligature. Another proof of the circulation being performed in this manner, is derived from microscopic observations, on the transparent parts of animals, in which the blood can be seen to move towards the extremities, along the arteries, and return by the veins. The blood, however, does not flow out of the heart into the arteries in a continued stream, but by jets, or pulses; when the ventricles are filled with blood from the auricles, this blood stimulates them, and thereby causes them to contract; by such contraction, they force the blood, which they contain, into the arteries; this contraction is called the systole of the heart. As soon as they have finished their contraction, they relax, till they are again filled with blood from the auricles, and this state of relaxation of the heart, is called the diastole. This causes the pulsation or beating of the heart. The arteries must, of course, have a similar pulsation, the blood being driven into them only by starts; and accordingly we find it in the artery of the wrist; this beating we call the pulse; the like may also be observed in the arteries of the temples, and other parts of the body. The veins, however, have no pulsation, for the blood flowing on, in an uninterrupted course, from smaller tubes to wider, its pulse becomes entirely destroyed. The different cavities of the heart do not contract at the same time; but the two auricles contract together, the ventricles being at that time in a state of relaxation; these ventricles then contract together, while the auricles become relaxed. Both the arteries and veins may be compared to a tree, whose trunk is divided into large branches; these are subdivided into smaller, the smaller again into others still smaller; and we may observe, likewise, that the sum of the capacities of the branches, which arise from any trunk, is always greater than the capacity of the trunk. The minutest branches of the arteries, being reflected, become veins, or else they enter veins that are already formed, by anastomosis, as it is called; the small veins continually receiving others, become, like a river, gradually larger, till they form the venae cavae, which conduct the blood to the heart. Anatomical injections prove, that the last branches of the arteries terminate in the beginning of veins; but it is the opinion of many celebrated physiologists, that the arteries carry the blood to the different parts of the body to nourish them, and that the veins commence by open mouths, which absorb or suck up what is superfluous, and return it back to the heart. From what has been said, it must be evident that there is a considerable resemblance between the circulation of the blood in the animal body, and the circulation of the aqueous fluid on the surface of the globe. In the latter case the water is raised from the ocean, by the heat of the sun, and poured down upon the dry land, in minute drops, for the nourishment and economy of its different parts. What is superfluous is collected into little rills; these meeting with others, form brooks; the union of which produce rivers, that conduct the water to its original source, from which it is again circulated. In the same manner, the blood is sent by the heart to different parts of the body, for the nourishment and economy of its different parts; what is superfluous is brought back by veins, which, continually uniting, form those large trunks, which convey the vital fluid to the heart. The blood does not circulate, however, in the manner which I have mentioned, in all parts of the body; for that which is carried by arteries to the viscera, serving for digestion, such as the stomach, bowels, mesentery, omentum, and spleen, is collected by small veins which unite into a large trunk called the vena portarum; this vein enters the liver, and is subdivided in it like an artery, distributing through the liver a great quantity of blood, from which the bile is secreted: and, having served this purpose, the blood is collected by small veins; these unite and form the hepatic vein, which pours the blood into the vena cava, to be conducted to the heart. The reason of this deviation, is probably, to diminish the velocity of the blood in the liver, for the secretion of the bile; which could not have been effected by means of an artery. The force which impels the blood, is, first, the contraction of the heart, which propels the blood into the arteries with great velocity; but this is not the only force concerned in keeping up the circulation; this is evident, from the diminished heat, and weakened pulse, in a paralytic limb, which ought not to take place, if the blood were propelled merely by the action of the heart. The arteries are possessed of an elastic and muscular power, by means of which they contract when they are distended or stimulated. It is however by the muscular power alone, that they assist in propelling the blood; for the elasticity of their coats can serve no other purpose than preserving the mean diameter of the vessel. If we suppose the arteries to be dilated by the blood, poured into them by the heart, they will, by their contraction, as elastic tubes, undoubtedly propel the blood: but supposing them to be perfectly elastic, the force of the heart will be just as much diminished in dilating them as the force of the blood is increased by their contraction. We are not however acquainted with any substance perfectly elastic, or which restores itself with a force equal to that with which it was distended: hence the elastic power of the arteries will subtract from, instead of adding to, the power of the heart. It is evident, therefore, that it must be by the muscular power of the arteries, which causes them to contract like the heart, that they propel the blood. That such is the case, appears from the muscular structure of the arteries observed by anatomists; as also from the effects of mechanical irritation of their coats, which causes them to contract; this is likewise evident from the inflammation produced by the application of stimulating substances to particular parts; for instance, cantharides and mustard. It appears likewise, from the secretion in some parts being preternaturally increased, while the motion of the general mass of the blood continues unaltered. The contraction of the arteries always propels the blood towards the extreme parts of the body: this must necessarily happen, because the valves at the origin of the arteries prevent its return to the heart, it must therefore move in the direction in which it finds least resistance. If it were not for this muscular power of the arteries, the force of the heart would not alone be able to propel the blood to the extreme parts of the body, and overcome the different kinds of resistance it has to encounter. Among the causes that lessen the velocity of the blood, may be mentioned the increasing area of the artery; for it was before observed, that the sum of the cavities of the branches from any trunk exceeded the cavity of the trunk: and from the principles of hydrostatics, the velocities of fluids, propelled by the same force, in tubes of different diameters, are inversely as the squares of the diameters, so that in a tube of double the diameter, the velocity will only be one fourth; in one of the triple, only one ninth: and since the arteries may be looked upon as conical, it is evident that the velocity of the blood must be diminished from this cause. The curvilinear course of the arteries likewise gives considerable resistance; for at every bending the blood loses part of its momentum against the sides; and this loss is evidently proportioned to the magnitude of the angle, at which the branch goes off. Convolutions are frequently made, in order to diminish the force of the blood in particular organs; this is especially the case with the carotid artery before it enters the brain. The angles which the ramifications of the arteries make, are greater or more obtuse nearer the heart, and more acute as the distance increases; by which means the velocity of the blood is rendered more equal in different parts. The anastomosing or union of different branches of arteries, likewise retards the velocity of the blood, the particles of which, from different vessels, impinging, disturb each other's motion, and produce a compound force, in which there is always a loss of velocity: and it is evident, from the composition of forces, that this loss must be proportioned to the obliquity of the angle at which the vessels unite. The adhesion of the blood to the sides of the vessels, likewise causes a loss of velocity in the minuter branches, which may be owing to a chemical affinity: the viscidity or imperfect fluidity of the blood is another retarding cause. All these causes united, would render it impossible for the heart to propel the blood with the velocity with which it moves in the very minute branches of the arteries, if these arteries were not endowed with a living muscular power like the heart, by which they contract and propel their contents. In the veins, the motion of the blood is occasioned partly by the vis a tergo, and partly by the contraction of the neighbouring muscles, which press upon the veins; and these veins being furnished with valves, the return of the blood towards the arteries is prevented; it must therefore move towards the heart. That the contraction of the muscles of the body tends very much to promote the circulation of the blood, is evident, from the increase of the circulation from exercise, and likewise from the languid motion of the blood in sedentary persons, and those given to indolence. Hence we may account for the different diseases to which such persons are subject, and know how to apply the proper remedies. Hence likewise, we see the reason why rest is so absolutely necessary in acute and inflammatory diseases, where the momentum of the blood is already too great. It has been doubted by anatomists, whether the veins were possessed with muscular power; but this seems now to be confirmed. Haller found the vena cava near the heart to contract on the application of stimulants, though he could see no muscular fibres; these, however, have been discovered by succeeding anatomists. The magnitude of the veins is always greater than that of the corresponding arteries; hence the velocity of the blood must be less in the veins; and hence likewise we may account for their want of pulsation; for the action of the heart upon the arteries is at first very great; but as we recede from the heart, this effect becomes less perceptible; the arterial tube increases both in size and muscularity, in proportion to its distance from the source of circulation. The powers of the heart are spent in overcoming the different resistances which I have noticed, before the blood enters the veins; hence the blood will flow uniformly in these last. The blood is subject in the veins to retarding causes, similar to those which operate in the arteries, but perhaps not in an equal degree; for the flexures are less frequent in the veins than in the arteries. As the capacity of the arterial tube increases with its distance from the heart, the velocity, from this cause, as has already been observed, is continually diminished; but a contrary effect takes place in the veins; for the different branches uniting, form trunks, whose capacities are smaller than the sums of the capacities of the branches, hence the velocity of the blood in the veins will increase as it approaches the heart. Another retarding cause may be mentioned, namely, gravity, which acts more on the venous than the arterial system. The effects of gravity on the veins may be exemplified, by a ring being pulled off the finger with ease when the hand is elevated; also by the swellings of the feet that occur in relaxed habits, which swellings increase towards night, and subside in the morning, after the body has been in a horizontal posture for some hours. In weak persons, the frequency of the pulse is increased by an erect posture, which may probably depend on gravity; as we know, from the observations of Macdonald and others, that an erect posture will make a difference of 15 or 20 beats in a minute. The experiments alluded to, were made by gently raising a person fastened to a board, where there being no muscular exertion, respiration would not be increased; so that the whole effect was probably owing to gravity accelerating the column of arterial blood. The inverted posture produces a still more remarkable effect in accelerating the pulse, than the erect, for it sometimes causes it to beat 10 or 12 times more in the former case than in the latter. While we are on this subject, it may not be improper to take notice of the effects of swinging on the circulation, which have been found by Dr. Carmichael Smyth, and others, to diminish the strength and velocity to such a degree, as to bring on fainting. These effects have never been satisfactorily accounted for; but they would seem to admit of an easy explanation on mechanical principles: they are undoubtedly owing, at least in a great measure, to the centrifugal force acquired by the blood. By a centrifugal force, I mean, the tendency which revolving bodies have to fly off from the centre, which arises from their tendency to move in a straight line, agreeably to the laws of motion. Hence a tumbler of water may be whirled in a circle vertically without spilling it; the centrifugal force pushing the water against the bottom of the tumbler. In the same manner when the human body is made to revolve vertically in the arch of a circle, this centrifugal force will propel the blood from the head and heart towards he extremities; hence the circulation of the blood will be weakened, and the energy of the brain diminished. The contrary, however, will take place on a horizontal swing, as I have frequently observed, both on myself and others; for the centrifugal force in this case will propel the blood from the extremities towards the head. It has been already observed, that the pulsations of the artery which we feel at the wrist, are occasioned by its alternate dilatations and contractions, which vary according to the strength and regularity of the circulation, which is liable to be affected by the smallest changes in the state of health. Hence physicians make use of the pulse as a criterion whereby to judge of the health of the body. And we may observe that there are few more certain characteristics of the state of the body than the pulse; yet the conclusions that have been drawn from it have often been erroneous; and this has arisen from trusting to observation without the aid of reason. That we may better understand the phenomena of the pulse, I shall lay down the following postulata. 1st. It is now generally believed, that every part of the arterial system is endowed with irritability, or a power of contracting on the application of a stimulus, and that the blood acting on this contractibility, if the term may be allowed, causes contraction; and that the alternate relaxation and contraction gives the phenomenon pulsation. 2d. The greater the action of the stimulus of the blood, the greater will be the contraction, that is, the nearer will the sides of the artery approach towards the axis. 3d. That the velocity with which a muscular fibre, in a state of debility, contracts, is at least equal to that with which a fibre in a state of strength contracts, is a fact generally allowed by physiologists. We shall afterwards see, that a deficient action of stimulus on the vessels may arise, either directly from diminishing the quantity of blood contained in them, or indirectly, from the application of too great a stimulant power, which has diminished the capability of contracting inherent in the vessels. From these postulata, it will be evident, that the greater the action of the arteries, that is, the more powerful their contraction, the longer will be the intervals between the pulsations. For the velocity being at least equal in debility and in strength, the times between the pulsations will be proportioned to the approach of the sides of the artery towards its axis: but the approach of the sides towards the axis is greater when the arteries are in a state of vigour than when debilitated; consequently the intervals between the pulsations will be greater when the arteries are in a state of vigour than when debilitated. Hence it is evident, that a frequency of pulse must generally indicate a diminished action or debility; while a moderate slowness indicates a vigorous or just action. Hence likewise the opinion of increased action, which has been supposed to take place in fevers, because a frequent pulse was observed, must be false, because the frequency arises from a directly opposite state, and indicates a diminished action of the vascular system. In a sound and adult man the frequency of the pulse is about seventy beats in a minute; and in an infant, within the first five or six months, the pulse is seldom less than one hundred and twenty, and diminishes in frequency as the child grows older. But though seventy beats in the minute may be taken as a general standard; yet in persons of irritable constitutions the frequency is greater than this, and many, who are in the prime of life, have the pulse only between fifty and sixty. It is generally observed, that the pulse is slower in the morning, that it increases in frequency till noon, after dinner it again becomes slow, and in the evening its frequency returns, which increases till midnight. These phenomena may be rationally explained on the principles just laid down. When we rise in the morning, the contractibility being abundant, the stimulus of the blood produces a greater effect, the pulse becomes slow, and the contractions strong; it becomes more frequent, however, till dinner time, from a diminished contractibility; after dinner, from the addition of the stimulus of food and chyle, it again decreases in frequency, and becomes slow till the evening, when its frequency returns, because the contractibility becomes exhausted: and this frequency continues till the vital power have been recruited by sleep. By the same principles it is easy to explain the quickness of the pulse in infancy, its gradual decrease till maturity, its slowness and strength during the meridian of life, and the return of its frequency during the decline. Having now described the phenomena of the circulation, it will be proper to examine the changes produced by this function on the blood; and, in the first place, it may be observed, that the blood which returns by the vena cava to the heart, is of a dark colour inclining to purple; while that which passes from the left ventricle into the arteries, is of a bright vermilion hue. The blood which is found in the pulmonary artery has the same dark purple colour with that in the vena cava, while that in the pulmonary vein resembles the aortal blood in its brightness. Hence it would appear, that the blood, during its passage through the lungs, has its colour changed from a dark purple to a bright vermilion, in which state it is brought by the pulmonary vein to the left auricle of the heart; this auricle, contracting, expels the blood into the corresponding ventricle, by whose action, and that of the arteries, it is distributed to all parts of the body. When it returns, however, by the veins, it is found to have lost its fine bright colour. It would appear, therefore, that the blood obtains its red colour during its passage through the lungs, and becomes deprived of it during its circulation through the rest of the body. That the blood contains iron, may be proved by various experiments: if a quantity of blood be exposed to a red heat in a crucible, the greatest part will be volatilised and burnt; but a quantity of brown ashes will be left behind, which will be attracted by the magnet. If diluted sulphuric acid be poured on these ashes, a considerable portion of them will dissolve; if into this solution we drop tincture of galls, a black precipitate will take place, or if we use prussiate of potash, a precipitate of prussian blue will be formed. These facts prove, beyond doubt, that a quantity of iron exists in the blood. I shall not now particularly inquire how it comes there; it may partly be taken into the blood along with the vegetable and animal food, which is received into the stomach; for the greatest part of the animal and vegetable substances, which we receive as food, contain a greater or less quantity of iron. Or it may be partly formed by the animal powers, as would appear from the following circumstance. The analysis of an egg, before incubation, affords not the least vestige of iron, but as soon as the chick exists, though it has been perfectly shut up from all external communication, if the egg be burnt, the ashes will be attracted by the magnet. But, however we may suppose the blood to obtain its iron, it certainly does contain it; if the coagulable lymph and serum of the blood be carefully freed from the red particles, by repeated washing, the strictest analysis will not discover in either of them a particle of iron, while the red globules thus separated will be found to contain a considerable quantity of this metal. That the red colour of the blood depends upon iron, appears likewise from the experiments of Menghini, which show, that the blood of persons who have been taking chalybeate medicines for some time, is much more florid that it is naturally; the same is agreeable to my own observation. A late analysis, by Fourcroy, has likewise proved, that the red colour of the blood resides in the iron; but, though the red colour of the blood may reside in the iron which it contains, we shall find that this colour is likewise connected with oxidation. If the dark coloured blood, drawn from the veins, be put under a vessel containing oxygen gas, its surface will immediately become florid, while the bulk of the gas will be diminished. Mr. Hewson enclosed a portion of a vein between two ligatures, and injected into it a quantity of oxygen gas; the blood, which was before dark coloured, instantly assumed the hue of arterial blood. Thuvenal put a quantity of arterial blood under the receiver of an air pump; on exhausting the air it became of the dark colour of venous blood; on readmitting the air, it became again florid. He put it under a receiver filled with oxygen gas, and found the florid colour much increased. Dr. Priestly exposed the blood of a sheep successively to oxygen gas, atmospheric air, and carbonic acid gas; and found, that in oxygen gas its colour became very florid, less so in atmospheric air, and in carbonic acid gas it became quite black. He filled a bladder with venous blood, and exposed it to oxygen gas; the surface in contact with the bladder immediately became florid, while the interior parts remained dark coloured. All these facts prove, that the red colour which the blood acquires in the lungs, is owing to the oxygen, which probably combines with it, and the last mentioned fact shows, that oxygen will act on the blood, even though a membrane similar to the bladder, be interposed between them. The same effect, probably, takes place in the lungs; the blood is circulated through that organ by a number of fine capillary arteries; and it is probable that the oxygen acts upon the blood through the membranes of these arteries, in the same manner that it does through the bladder. In short, it seems likely, that the blood, during its circulation through the lungs, becomes combined with oxygen; that this oxidated blood, on its return to the heart, is circulated by the arteries to all parts of the body; and that, during this circulation, its oxygen combines with the hydrogen and carbon of the blood, and perhaps with those parts of the body with which it comes into contact; it is therefore brought back to the heart, by the veins, of a dark colour, and deprived of the greatest part of its oxygen. This is the most probable theory, in the present state of our knowledge; it was proposed by Lavoisier, who imagines the focus of heat, or fireplace to warm the body, to be in the lungs: others, however, have thought it more consonant to facts, to suppose, that, instead of the oxygen uniting with carbon and hydrogen in the lungs, and there giving out its heat, the oxygen is absorbed by the blood, and unites with these substances during the circulation, so that heat is produced in every part of the body; and this doctrine seems certainly supported by several facts and experiments. The circulation of the blood, though so simple and beautiful a function, was unknown to the ancient physicians, and was first demonstrated by our countryman, Harvey; when he first published his account of this discovery, he met with the treatment which is generally experienced by those who enlighten and improve the comfort of their fellow creatures, by valuable discoveries. The novelty and merit of this discovery drew upon him the envy of most of his contemporaries in Europe, who accordingly opposed him with all their power; and some universities even went so far, as to refuse the honours of medicine to those students, who had the audacity to defend this doctrine; but afterwards, when they could not argue against truth and conviction, they attempted to rob him of the discovery, and asserted that many of the ancient physicians, and particularly Hippocrates, were acquainted with it. Posterity, however, who can alone review subjects of controversy without prejudice, have done ample justice to his memory. LECTURE IV. DIGESTION, NUTRITION, &c. The human body, by the various actions to which it is subject, and the various functions which it performs, becomes, in a short time, exhausted; the fluids become dissipated, the solids wasted, while both are continually tending towards putrefaction. Notwithstanding which, the body still continues to perform its proper functions, often for a considerable length of time; some contrivance, therefore, was necessary to guard against these accelerators of its destruction. There are two ways in which the living body may be preserved; the one by assimilating nutritious substances, to repair the loss of different parts; the other to collect, in secretory organs, the humours secreted from these substances. We are admonished of the necessity of receiving substances into the body, to repair the continual waste, by the appetites of hunger and thirst. For the stomach being gradually emptied of its contents, and the body, in some degree, exhausted by exercise, we experience a disagreeable sensation in the region of the stomach, accompanied by a desire to eat, at first slight, but gradually increasing, and at last growing intolerable, unless it be satisfied. When the fluid parts have been much dissipated, or when we have taken, by the mouth, any dry food, or acrid substance, we experience a sensation of heat in the fauces, and at the same time a great desire of swallowing liquids. The former sensation is called hunger, and the latter thirst. From the back part of the mouth passes a tube, called the oesophagus or gullet, its upper end is wide and open, spread behind the tongue to receive the masticated aliment: the lower part of this pipe, after it has passed through the thorax, and pierced the diaphragm, enters the stomach, which is a membranous bag, situated under the left side of the diaphragm: its figure nearly resembles the pouch of a bagpipe, the left end being most capacious; the upper side is concave, and the lower convex: it has two orifices, both on its upper part; the left, which is a continuation of the oesophagus, and through which the food passes into the stomach, is named cardia; and the right, through which the food is conveyed out of the stomach, is called pylorus: within this last orifice is a circular valve, which, in some degree, prevents the return of the aliment into the stomach. From the pylorus, or right orifice of the stomach, arise the intestines, or bowels, which consist of a long and large tube, making several circumvolutions, in the cavity of the abdomen; this tube is about five or six times as long as the body to which it belongs. Though it is one continued pipe, it has been divided, by anatomists, into six parts, three small, three large. The three small intestines are the duodenum, the jejunum, and the ileum; the duodenum commences at the pylorus, and is continued into the jejunum, which is so called from its being generally found empty: the ileum is only a prolongation of the jejunum, and terminates in the first of the great intestines, called the caecum. The other great guts are the colon and the rectum. The whole of what has been described is only a production of the same tube, beginning at the oesophagus. It is called by anatomists the intestinal canal, or prima via, because it is the first passage of the food. It has circular muscular fibres, which give it a power of contracting when irritated by distension; and this urges forward the food which is contained in it. This occasions a worm like motion of the whole intestines, which is called their peristaltic motion. The mesentery is a membrane beginning loosely on the loins, and thence extending to all the intestines; which it preserves from twisting by their peristaltic motion. It serves also to sustain all the vessels going to and from the intestines, namely the arteries, veins, lacteals, and nerves; it also contains several glands, called, from their situation, mesenteric glands. The lacteal vessels consist of a vast number of fine pellucid tubes, which arise by open mouths from the intestines, and proceeding thence through the mesentery, they frequently unite, and form fewer and larger vessels, which pass through the mesenteric glands, into a common receptacle or bag, called the receptacle of the chyle. The use of these vessels is to absorb the fluid part of the digested aliment, called chyle, and convey it into the receptacle of the chyle, that it may be thence carried through the thoracic duct into the blood. The receptacle of the chyle is a membranous bag, about two thirds of an inch long, and one third of an inch wide, at its superior part it is contracted into a slender membranous pipe, called the thoracic duct, because its course is principally through the thorax; it passes between the aorta and the vena azygos, then obliquely over the oesophagus, and great curvature of the aorta, and continuing its course towards the internal jugular vein, it enters the left subclavian vein on its superior part. There are several other viscera besides those I have described, which are subservient to digestion; among these may be mentioned the liver, gall bladder, and pancreas. The liver is the largest gland in the body, and is situated immediately under the diaphragm, principally on the right side. Its blood vessels that compose it as a gland, are the branches of the vena portarum, which, as I mentioned in the last lecture, enters the liver and distributes its blood like an artery. From this blood the liver secretes the bile, which is conveyed by the hepatic duct, towards the intestines: before this duct reaches the intestines, it is joined by another, coming from the gall bladder: these two ducts uniting, form a common duct, which enters the duodenum obliquely, about four inches below the pylorus of the stomach. The gall bladder, which is a receptacle of bile, is situated between the stomach and the liver; and the bile which comes from the liver, along the hepatic duct, partly passes into the duodenum, and partly along the cystic duct into the gall bladder. When the stomach is full, it presses on the gall bladder, which will squeeze out the bile into the duodenum at the time when it is most wanted. The bile is a thick bitter fluid, of a yellowish green colour, composed chiefly of soda and animal oil, forming a soap; and it is most probably in consequence of this saponaceous property that it assists digestion, by causing the different parts of the food to unite together by intermediate affinity. When the bile is prevented from flowing into the intestines, by any obstruction in the ducts, digestion is badly performed, costiveness takes place, and the excrements are of a white colour, from being deprived of the bile. This fluid, stagnating in the gall bladder, is absorbed by the lymphatics, and carried into the blood, communicating to the whole surface of the body a yellow tinge, and other symptoms of jaundice. The jaundice therefore is occasioned by an obstruction to the passage of the bile into the intestines, and its subsequent absorption into the blood: this obstruction may be caused either by concretions of the bile, called gall stones, or by a greater viscidity of the fluid, or by a spasm, or paralysis of the biliary ducts. The pancreas, or sweet bread, is a large gland lying across the upper and back part of the abdomen, near the duodenum. It has a short excretory duct, about half as wide as a crow quill, which enters the duodenum at the same place where the bile duct enters it. The food being received into the mouth, is there masticated or broken down, by the teeth, and impregnated with saliva, which is pressed out of the salivary glands, by the motions of the jaw and the muscles of the mouth. It then descends, through the oesophagus, into the stomach, where it becomes digested, and, in a great measure, dissolved, by the gastric juice, which is secreted by the arteries of the stomach. It is then pushed through the pylorus, or right orifice of the stomach into the duodenum, where it becomes mixed with the bile from the gall bladder and liver, and the pancreatic juice from the pancreas. These fluids seem to complete the digestion: after this, the food is continually moved forwards by the peristaltic motion of the intestines. The chyle, or thin and milky part of the aliment, being absorbed by the lacteals, which rise, by open mouths, from the intestines, is carried into the receptacle of the chyle, and from thence the thoracic duct carries it to the subclavian vein, where it mixes with the blood, and passes with it to the heart. The food of animals is derived from the animal or vegetable kingdoms. There are some animals which eat only vegetables, while others live only on animal substances. The number and form of the teeth, and the structure of the stomach, and bowels, determine whether an animal be herbivorous, or carnivorous. The first class have a considerable number of grinders, or dentes molares; and the intestines are much more long and bulky; in the second class, the cutting teeth are predominant, and the intestines are much shorter. Man seems to form an intermediate link between these two classes: his teeth, and the structure of the intestines, show, that he may subsist both on vegetable and animal food; and, in fact, he is best nourished by a proper mixture of both. This appears from those people who live solely on vegetables, as the Gentoo tribes, and those who subsist solely on animals, as the fish eaters of the northern latitudes, being a feebler generation than those of this country, who exist on a proper mixture of both. A due proportion, therefore, of the two kinds of nourishment, seems undoubtedly the best. Having taken a general view of the course of the aliment into the blood, I shall now examine more particularly, how each part of the organs concerned in digestion, or connected with that function, contributes to that end. The food being received into the mouth, undergoes various preparations, which fit it for those changes it is afterwards to undergo. By the teeth the parts of it are divided and ground, softened and liquified by the saliva, and properly compressed by the action of the tongue and mastication. The mouth, in most animals, is armed with very hard substances, which, by the motion of the lower jaw, are brought strongly into contact. Those parts of the teeth which are above the sockets, are not simply bony, they are much harder than the bones, and possess the property of resisting putrefaction, as long as this hard crust continues to cover them. The teeth are divided into three classes: 1st. The cutting teeth, which are sharp and thin, and which serve to cut or divide the food: 2nd. The canine teeth, which serve to tear it into pieces still smaller: 3rd. The grinders, which present large and uneven surfaces, and actually grind the substance already broken down by the other teeth. Birds, whom nature has deprived of teeth, have a strong muscular stomach, called the gizzard, which serves the purposes of teeth, and they even take into the stomach small pieces of grit, to assist in grinding to a powder the grain that they have swallowed. Among those parts of the mouth which contribute to the preparation of the food, we must reckon the numerous glands which secrete saliva, and which have therefore been called salivary glands. The saliva is a saponaceous liquor, destitute of taste or smell, which is squeezed out from these glands, and mixed with the food during mastication. In the mouth, therefore, the food becomes first broken down by the teeth, impregnated with saliva, and reduced to a soft pasty substance, capable of passing with these, through the oesophagus, into the stomach. It is here that it undergoes the change, which is particularly termed digestion. Digestion comprehends two classes of phenomena, distinct from each other: 1st. Physical and chemical: 2nd. Organic and vital. The object of the first, is to bring the alimentary substances to such a state as is necessary, that they may be capable of the new combinations into which they are to enter, to obtain the animal character. The object of the second is, to produce those combinations which some have thought to be very different from those produced by simple chemical attractions. The physical and chemical phenomena of digestion, relate chiefly, 1st. To the action of heat; 2ndly. To the dissolution of the alimentary substances. The heat of the animal is such, as is well fitted to promote solution. That digestion is performed by solution, is evident, from several experiments, particularly those made by Dr. Stevens, who enclosed different alimentary substances in hollow spheres of silver, pierced with small holes. These were swallowed, and after remaining some time in the stomach, the contents were found dissolved. The great agent of solution is the gastric juice, which possesses a very strong solvent power. This juice is secreted by the arteries of the stomach; it may be collected in considerable quantity, by causing an animal that has been fasting for some time, to swallow small hollow spheres, or tubes of metal filled with sponge. This liquid does not act indiscriminately upon all substances; for if grains of corn be put into a perforated tube, and a granivorous bird be made to swallow it, the corn will remain the usual time in the stomach without alteration; whereas if the husk of the grain be previously taken off, the whole of it will be dissolved. There are many substances likewise which pass unaltered through the intestines of animals, and consequently are not acted upon by the gastric juice. This is the case frequently with grains of oats, when they have been swallowed by horses entire, with their husks on. This is the case likewise with the seeds of apples and other fruits, when swallowed entire by man; yet if these substances have been previously ground by the teeth, they will be digested. It would appear therefore, that it is chiefly the husk or outside of these substances which resists the action of the gastric juice. This juice is not the same in all animals; for many animals cannot digest the food on which others live. Thus sheep live wholly on vegetables, and if they are made to feed on animals, their stomachs will not digest them: others again, as the eagle, feed wholly on animal substances, and cannot digest vegetables. The accounts of the experiments made on gastric juice are very various: sometimes it has been found of an acid nature, at other times not. The experiments of Spallanzani show, however, that this acidity is not owing to the gastric juice, but to the food. The result of his experiments, which have been very numerous, prove, that the gastric juice is naturally neither acid nor alkaline. No conclusion, however, can be drawn from these experiments made out of the stomach, with respect to the nature of the gastric juice; nor do the analyses which have been made of it throw any light on its mode of action. But, from the experiments which have been made on digestion, in the stomach, particularly by Spallanzani, the following facts have been established. The gastric juice attacks the surfaces of bodies, and combines chemically with their particles. It operates with more energy and rapidity, the more the food is divided, and its action increased by a warm temperature. By the action of digestion, the food is not merely reduced to very minute parts, but its chemical properties become changed; its sensible properties are destroyed, and it acquires new and very different ones. This juice does not act as a ferment; so far from it, it is a powerful antiseptic, and even restores flesh which is already putrid. When the alimentary substances have continued a sufficient time in the stomach, they are pushed into the intestines, where they become mixed with the bile and pancreatic juice, as was before observed. What changes are caused by these substances, we have yet to learn; but there is no doubt, that they serve some important purposes. By the peristaltic motion of the bowels, the alimentary matters thus changed are carried along, and applied to the mouths of the lacteal vessels, which open into the intestines, like a sponge, and by some power, not well understood, absorb that part which is fitted for assimilation, while the remainder is rejected as an excrement. The lacteal vessels are furnished with valves, which allow a free passage to the chyle from the intestines, but prevent its return. The most inexplicable thing in this operation, is the power which these vessels possess of selecting from the intestinal mass, those substances which are proper for nutrition, and rejecting those which are not. These lacteal vessels, as was before observed, pass through the mesentery, and their contents seem to undergo some important change in the mesenteric glands. The chyle which passes through vessels, appears to be an oily liquor, less animalised than milk, and its particles seem to be held in solution by the intermedium of a mucilaginous principle. It is conveyed along the thoracic duct in the manner already described, and enters the blood slowly, and, as it were, drop by drop, by the subclavian vein; in this way it becomes intimately mixed with the blood, and combining with oxygen in the lungs, it acquires a fibrous character, and becomes fit to nourish the body. We have now seen how the process of digestion is performed, at least, so far as we are acquainted with it, and how its products are conveyed into the blood. But to what purposes the blood is employed, which is formed with so much care, we have yet to discover. It seems to answer two purposes. The parts of which the body is composed, namely, bones, muscles, ligaments, membranes, &c. are continually changing: in youth they are increasing in size and strength, and in mature age they are continually acting, and, consequently, continually liable to waste and decay. They are often exposed to accidents, which render them unfit for performing their various functions; and even when no such accidents happen, it seems necessary for the health of the system that they should be perpetually renewed. Materials must therefore be provided for repairing, increasing, or renewing all the various organs of the body. The bones require phosphate of lime, and gelatine, the muscles fibrine, and the cartilages and membranes albumen; and accordingly we find all these substances contained in the blood, from whence they are drawn, as from a storehouse, whenever they are wanted. The process by which these different parts of the blood become various parts of the body is called assimilation. Over the nature of assimilation the thickest darkness still hangs; all that we know for certain is, that there are some conditions necessary to its action, without which it cannot take place. These are, 1. A sound and uninterrupted state of the nerves. 2. A sound state of the blood vessels. 3. A certain degree of tone or vigour in the vessels of the part. There remains yet to be noticed another set of vessels, connected with the circulating and nutritive systems, called lymphatics. These vessels are very minute, and filled with a transparent fluid: they rise by open mouths in every cavity of the body, as well as from every part of the surface, and the course of those from the lower extremities, and indeed from most of the lower parts of the body, is towards the thoracic duct, which they enter at the same time with the lacteal vessels already described. They are furnished, like the lacteals, with numerous valves, which prevent their contents from returning towards their extremities. The minute arteries in every part of the body exhale a colourless fluid, for lubricating the different parts, and other important purposes: and the lymphatic vessels absorb the superfluous quantity of this fluid, and convey it back to the blood. It must be evident therefore, that, if the lymphatics in any cavity become debilitated, or by any other means be prevented from absorbing this exhaled fluid, an accumulation of it will take place: the same will happen, if the exhaling arteries be debilitated, so as to allow a greater quantity of fluid to escape than the absorbents can take up. When the balance between exhalation and absorption is destroyed, by either or both of these means, a dropsy will be the consequence. Before we finish the subject of digestion, I shall take a short view of some of the morbid affections, attending this important function of the animal economy. A deficiency of appetite may arise, either from an affection of the stomach, or a morbid state of the body: for there is such a sympathy between the stomach and the rest of the system, that the first is very seldom disordered, without communicating more or less disorder to the system: nor can the system become deranged and the stomach remain sound. A want of appetite may arise from overloading the stomach, whereby its digestive powers will be weakened. And this may be occasioned in two ways. First, by taking food of the common quality in too great quantity, which will certainly weaken the powers of the stomach. An excellent rule, and one which if more attended to, would prevent the dreadful consequences of indigestion, is always to rise from the table with some remains of appetite. This is a rule applicable to every constitution, but particularly to the sedentary and debilitated. The second way in which the stomach may be debilitated, is by taking food too highly stimulating or seasoned; and this even produces much worse effects than an over dose with respect to quantity. The tone of the stomach is destroyed, and a crude unassimilated chyle is absorbed by the lacteals, and carried into the blood, contaminating its whole mass. Made dishes, enriched with hot sauces, stimulate infinitely more than plain food, and bring on diseases of the worst kind: such as gout, apoplexy, and paralysis. "For my part," says an elegant writer, "when I behold a fashionable table set out in all its magnificence, I fancy I see gouts, and dropsies, fevers, and lethargies, with other innumerable distempers, lying in ambuscade among the dishes." All times of the day are not equally fitted for the reception of nourishment. That digestion may be well performed, the functions of the stomach and of the body must be in full vigour. The early part of the day therefore is the proper time for taking nutriment; and, in my opinion, the principal meal should not be taken after two or three o'clock, and there should always be a sufficient time between each meal to enable the stomach to digest its contents. I need not remark how very different this is from the common practice of jumbling two or three meals together, and at a time of the day likewise when the system is overloaded. The breakfast at sunrise, the noontide repast and the twilight pillow, which distinguished the days of Elizabeth, are now changed for the evening breakfast, and the midnight dinner. The evening is by no means the proper time to take much nourishment: for the powers of the system, and particularly of the stomach, are then almost exhausted, and the food will be but half digested. Besides, the addition of fresh chyle to the blood, together with the stimulus of food acting on the stomach, always prevents sleep, or renders it confused and disturbed, and instead of having our worn out spirits recruited, by what is emphatically called by Shakespeare, "the chief nourisher in life's feast," and rising in the morning fresh and vigorous, we become heavy and stupid, and feel the whole system relaxed. It is by no means uncommon, for a physician to have patients, chiefly among people of fashion and fortune, who complain of being hot and restless all night, and having a bad taste in the mouth in the morning. On examination, I have found that, at least in nineteen cases out of twenty, this has arisen from their having overloaded their stomachs, and particularly from eating hot suppers; nor do I recollect a single instance of a complaint of this kind in any person not in the habit of eating such suppers. The immoderate use of spirituous and fermented liquors, is still more destructive of the digestive powers of the stomach; but this will be better understood, when we have examined the laws by which external powers act upon the body. The remarks I have made could not, however, I think, have come in better, than immediately after our examination of the structure of the digestive organs, as the impropriety of intemperance, with respect to food, is thus rendered more evident. The appetite becomes deficient from want of exercise, independently of the other causes that have been mentioned. Of all the various modes of preserving health, and preventing diseases, there is none more efficacious than exercise; it quickens the motion of the fluids, strengthens the solids, causes a more perfect sanguification in the lungs, and, in short, gives strength and vigour to every function of the body. Hence it is, that the Author of nature has made exercise absolutely necessary to the greater part of mankind for obtaining means of existence. Had not exercise been absolutely necessary for our well being, says the elegant Addison, nature would not have made the body so proper for it, by giving such an activity to the limbs, and such a pliancy to every part, as necessarily produce those compressions, extensions, contortions, dilatations, and all other kinds of motion, as are necessary for the preservation of such a system of tubes and glands. We may, indeed, observe, that nature has never given limbs to any animal, without intending that they should be used. To fish she has given fins, and to the fowls of the air wings, which are incessantly used in swimming and flying; and if she had destined mankind to be eternally dragged about by horses, her provident economy would surely have denied them legs. The appetite becomes deficient on the commencement of many diseases, but this is to be looked upon here rather as a salutary than as a morbid symptom, and as a proof that nature refuses the load, which she can neither digest nor bear with impunity. In healthy people the appetite is various, some requiring more food than others; but it sometimes becomes praeternaturally great, and then may be regarded as a morbid symptom. The appetite may be praeternaturally increased, either by an unusual secretion of the gastric juice, which acts upon the coats of the stomach, or by any acrimony, either generated in, or received into the stomach, or, lastly, by habit, for people undoubtedly may gradually accustom themselves to take more food than is necessary. The appetite sometimes becomes depraved, and a person thus affected, feels a desire to eat substances that are by no means nutritious, or even esculent: this often depends on a debilitated state of the whole system. There are some instances, however, in which this depravity of the appetite is salutary; for example, the great desire which some persons, whose stomachs abound with acid, have for eating chalk, and other absorbent earths: likewise, the desire which scorbutic patients have for grass, and other fresh vegetables. Appetites of this kind, if moderately indulged in, are salutary, rather than hurtful. The appetite for liquids as well as solids is sometimes observed to be deficient, and sometimes too great. The former can scarcely be considered as a morbid symptom, provided the digestion and health be otherwise good. But when along with diminished thirst, the fauces and tongue are dry, this deficiency may be regarded as a morbid and dangerous symptom. A more common morbid symptom, however, is too great thirst, which may arise from a deficiency of fluids in the body, produced by violent exercise, perspiration, too great a flow of urine, or too great an evacuation of the intestines. A praeternatural thirst may likewise arise from any acrid substance received into the stomach, which our provident mother, nature, teaches us to correct by dilution; this is the case with respect to salted meats, or those highly seasoned with pepper. It may arise also from the stomach being overloaded with unconcocted aliment, or from a suppressed or diminished secretion of the salivary liquors in the mouth, which may arise from fever, spasm, or affections of the mind; an increased thirst may likewise take place, from a derivation or determination of the fluids to other parts of the body; of this, dropsy affords an example. Indeed, various causes may concur to increase the thirst; this is the case in most fevers, where great thirst is occasioned by the dissipation of the fluids of the body by heat, as well as by the diminished secretion of the salivary humours which should moisten the mouth; to which may be added, the heat and diminished concoctive powers of the stomach. From what has been said, we can easily understand, why praeternatural thirst may sometimes be a necessary instinct of nature, at other times, an unnecessary craving; why acids, acescent fruits, and weak fermented liquors quench thirst more powerfully than pure water; and lastly, why thirst, in some instances, may be relieved by emetics, when it has resisted other remedies. There is no organ of the body whose functions are so easily deranged as those of the stomach; and these derangements prove a very fertile source of disease; they ought, therefore, carefully to be guarded against; and it is fortunate for us that we have this generally in our power, if we would but avail ourselves of it: for most of the derangements proceed from the improper use of food and drink, and a neglect of exercise. Indeed, when we examine, we shall find but a short list in the long catalogue of human diseases, which it is not in our power to guard against and prevent: and which surely will be guarded against, when their causes are known, and consequences understood. Among the diseases arising from a disordered state of the stomach and indigestion, may be enumerated the following: great oppression and anxiety, pain in the region of the stomach, with acid eructations, nausea, vomiting, the bowels sometimes costive, sometimes too loose, but seldom regular, depression of spirits, and all the long list, commonly, but very improperly, termed nervous complaints, deficient nutrition, and consequently general weakness, a relaxed state of the solids, too great a tenuity of the fluids, headach, vertigo, and many other complaints, too numerous to mention here. The greatest misfortune, and which indeed arises from a want of physiological knowledge, is, that people labouring under these disorders, imagine they may be cured by the reception of drugs into the stomach, and thus they are induced to receive into that organ, half the contents of an apothecary's shop. There is no doubt that these complaints may oftentimes be alleviated, and the cure assisted, by medicines: thus, when the stomach is overloaded, this may be removed by an emetic; the same complaint of the bowels may be removed by a cathartic; and when the stomach is debilitated, we are acquainted with some substances which will give it vigour, such as iron, the Peruvian bark, and several kinds of bitters. These however, when used alone, afford but temporary relief; and unless the cause which induced the disease be removed, it will afterwards return with redoubled violence. When the stomach, for instance, is debilitated by want of exercise, I would ask, is there an article in the whole materia medica, that can cure the complaints of sedentary people, unless proper exercise at the same time be taken? With exercise tonic remedies will undoubtedly accelerate the cure, but without it, they will only make bad worse. Again, when the stomach is debilitated by the use of improper food, or the abuse of fermented or spirituous liquors, I would say to any one who pretended to cure me of these complaints, without my making a total change in the manner of living, that he either was ignorant of the matter, or intended to deceive me. In many cases the change of food must be strictly observed and persevered in for a long time before a cure can be effected. In some instances where the powers of the stomach were too weak to prevent the food from undergoing perhaps both a vinous and acetous fermentation, and where, in consequence of the disengagement of gas and the formation of acid, the most excruciating pains were felt, the most dreadful sickness experienced, and all the symptoms of indigestion present in the most aggravated state; after almost every article in the materia medica, generally employed, had been tried without success, I have cured the patient merely by prohibiting food subject to fermentation, such as vegetables, and enjoining a strict use of animal food alone. In short, wherever the cause of a disease can be ascertained, the grand and simple secret in the cure, is the careful removal of that cause. LECTURE V. OF THE SENSES IN GENERAL. In this lecture, I propose to take a view of the connexion of man with the external world, and shall endeavour to point out the manner in which he becomes acquainted with external objects, by means of the faculties called senses. A human creature is an animal endowed with understanding, and reason; a being composed of an organized body, and a rational mind. With respect to his body, he is pretty similar to other animals, having similar organs, powers, and wants. All animals have a body composed of several parts, and, though these may differ from the structure of the human body in some circumstances, to accommodate it to peculiar habits and wants of the animal, still there is a great similarity in the general structure. The human body is feeble at its commencement, increases gradually in its progress by the help of nourishment and exercise, till it arrives at a certain period, when it appears in full vigour; from this time it insensibly declines to old age, which conducts it at length to dissolution. This is the ordinary course of human life, unless it happens to be abridged either by disease or accident. With regard to his reasoning faculties, or mind, man is eminently distinguished from other animals. It is by this noble part that he thinks, and is capable of forming just ideas of the different objects that surround him: of comparing them together; of inferring from known principles unknown truths; of passing a solid judgment on the mutual agreement of things, as well as on the relations they bear to him; of deliberating on what is proper or improper to be done; and of determining how to act. The mind recollects what is past, joins it with the present, and extends its views to futurity. It is capable of penetrating into the causes of events, and discovering the connexion that exists between them. Governed by invariable laws, which connect him with all the beings, whether animate or inanimate, among which he exists, man has certain relations of convenience, and inconvenience, arising from the particular constitution of the surrounding objects, as well as of his own body. These external objects possess qualities which may be useful or prejudicial to him; and his interest requires, that he should be capable of ascertaining and appreciating these properties. It is by sensation, or feeling, that the knowledge of external objects is obtained. The faculty of feeling, modified in every organ, perceives those qualities for which the peculiar structure of the organ is fitted; and all the various sensations of sound, colour, taste, smell, resistance, and temperature, find appropriate organs by which they are perceived, without mixing with, or confounding each other. External objects, therefore, act upon the parts of the body endowed with feeling, and their action is diversified in such a manner, as to give us a great number of sensations, which appear to have no resemblance to each other, and which make us acquainted with the various properties of surrounding objects. It would not, however, have been sufficient for man, merely to have possessed this power of perceiving the different properties of the objects which surround him: it was necessary likewise, that he should be possessed of motion, that he might be able to approach or avoid them, to seize or repulse them, as it suited his convenience or advantage. By the extreme mobility of his limbs, he is able to move his body, and transport it from place to place; to bring external objects nearer to him, to remove them to a greater distance, and to place them in such situations and such circumstances, as may enable them to act on each other, and produce the changes which he wishes. The human body, therefore, may be regarded as a machine composed (besides the moving parts which have formerly been noticed) of divers organs upon which external objects act, and produce those impressions which convince us of their presence, and make us acquainted with their properties. These impressions are transmitted to the sentient principle, or mind; and the faculty we possess of perceiving these impressions has been called by physiologists, sensibility. Sensation has generally been defined by metaphysicians to be a change in the mind, of which we are conscious, caused by a correspondent change in the state of the body. This definition, however, leaves the matter where they found it, and throws no light whatever on the nature of sensation; nor can we say any thing more concerning it, than that, when the organs are in a sound state, certain sensations are perceived, which force us to believe in the existence of external objects, though there is no similarity whatever, nor any necessary connexion, that we can perceive, between the sensation and the object which caused it. All the different degrees of sensation may be reduced to two kinds: pleasant and painful. The nature of these two primitive modes of sensation, is as little known to us as their different species: all that can be said, is, that the general laws by which the body is governed, are such, that pleasure is generally connected with those impressions which tend to its preservation, and pain with those which cause its destruction. In a general point of view, sensibility may be regarded as an essential property of every part of the living body, disposing each part to perform those functions, the object of which is to preserve the life of the animal. Sensibility presides over the most necessary functions, and watches carefully over the health of the body: she directs the choice of the air proper for respiration, and also of alimentary substances; the mechanism of the secretions is likewise placed under her power; and in the same way that the eye perceives colours, and the ear sounds, so every animated and living part is fitted to receive impressions from the objects appropriated to it. That every part of the animal is endowed with sensibility, is evident from a variety of facts, particularly from the action which follows when a muscle taken out of the animal body is irritated by any stimulus: this is evident, by a variety of facts mentioned by Whytt, Boerhaave, and others, which show, that parts recently taken from the animal body retain a portion of sensibility, which continues to animate them, and render them capable of action for a considerable time. The primary organ of sensation appears to be the brain, its continuation in the form of medulla oblongata and spinal marrow, and the various nerves proceeding from these; and it seems now generally agreed, that unless there be a free communication of nerves between the part where the impression is made, and the brain, no sensation will take place; for instance, if the nerves be cut or compressed. In a sound body, sensation is caused, whenever a change takes place in the state of the nervous power, whether that change be produced by an external, or an internal cause. The former kind of sensation is said to arise from impression or impulse, the latter from consciousness. Every impression or impulse is not, however, equally calculated to produce sensation; for this purpose, a middle degree of impulse appears the best. An impulse considerably less produces no sensation, and one more violent may cause pain, but no proper sensation denoting the presence or properties of external objects. Thus too small a degree of light makes no impression on the optic nerve; and if the object be too strongly illuminated, the eye is pained, but has no proper idea of the figure or colour of the object. In the same way, if the vibrations which give us an idea of sound, be either too quick or too slow, we shall not obtain this idea. When the vibration is too quick, a very disagreeable and irritating sensation is perceived, as for instance, in the whetting of a saw: and on the other hand, when the vibrations are too slow, they will not produce a tone or sound. This might be proved of all the senses, and shows, that a certain degree of impression is necessary to produce perfect sensation. There is another circumstance likewise requisite to produce sensation: it is not enough, that the impression should be of the proper strength; it is necessary likewise, that it should remain for some time, otherwise no sensation will be produced. There are many bodies whose magnitude is amply sufficient to be perceived by the eye; yet, by reason of their great velocity, the impulse they make on any part of the retina is so short, that they are not visible. This is proved by our not perceiving the motions of cannon and musket balls, and many other kinds of motion. On this principle depends the art of conjuration, or legerdemain; the fundamental maxim of those who practise them, is, that the motion is too quick for sight. If the impulse be of a proper degree, and be continued for a sufficient length of time, the impression made by it will not immediately vanish with the impulse which caused it, but will remain for a time proportioned to the strength of the impulse. This, with respect to sight, is proved by whirling a firebrand in a circular manner, by which the impression of a circle is caused, instead of a moving point: and, with respect to hearing, it may be observed, that when children run with a stick quickly along railing, or when a drum is beaten quickly, the idea of a continued sound is produced, because the impression remains some time: for it is evident, that the sounds produced in succession are perfectly distinct and insulated. Sensation likewise depends, in a great measure, on the state of the mind, and on the degree of attention which it gives. For if we are engaged in attention to any object, we are insensible of the impressions made upon us by others, though they are sufficiently strong to affect us at other times. Thus, when our attention is fixed strongly upon any particular object, we become insensible of the various noises that surround us, though these may be sometimes very loud. On the contrary, if our attention be upon the watch, we can perceive slight, and almost neglected impressions, while those of greater magnitude become insensible. The ticking of a clock becomes insensible to us from repetition, but if we attend to it, we become easily sensible of it, though at the same time we become insensible of much stronger impressions, such as the rattling of coaches in the streets. The attention depends in some degree on the will, but is generally given to those impressions which are particularly strong, new, pleasant, or disagreeable; in short, to those which particularly affect the mind. Hence it is, that things which are new, produce the most vivid impressions, which gradually grow fainter, and at last become imperceptible. There is one circumstance respecting sensation, which will probably account for our only perceiving those impressions to which the mind attends: and this is, that the mind is incapable of perceiving more than one impression at a time: the more accurately we examine this, the greater reason we shall have to think it true; but the mind can turn its attention so quickly, from one object to another, that at first sight, we are led to believe, that we are able to attend to several at the same time. But though the mind cannot perceive or attend to various sensations at the same time, yet if two or more of these are capable of uniting in such a manner as to produce a compound sensation, this may be perceived by the mind. This compound sensation may be produced either by impressions made at the same instant, or succeeding each other so quickly, that the second takes place before the first has vanished. As an instance of the first, we may mention musical chords, or the sounds produced by the union of two or more tones at the same time. We have another instance likewise in odours or smells; if two or more perfumes be mixed together, a compound odour will be perceived, different from any of them. As an instance of the latter, if a paper painted of various colours be made to revolve rapidly in a circle, a compound colour, different from any of them, will be perceived. These observations apply particularly to the senses we have mentioned, and likewise to taste: but the sensations afforded us by touch do not seem capable of being compounded in this manner. There are many things necessary to perfect sensation, besides those that have been mentioned. The degree and perfection of sensation will depend much on the mind, and will be continually altered by delirium, torpor, sleep, and other circumstances; much likewise depends on the state of the organs with respect to preceding impressions; for if any organ of sense have been subjected to a strong impression, it will become nearly insensible of those which are weaker. Of this innumerable instances may be given: an eye which has been subjected to a strong light, becomes insensible of a weaker: and on the contrary, if the organs of sense have been deprived of their accustomed impressions for some time, they are affected by very slight ones. Hence it is, that when a person goes from daylight into a darkened room, he can at first see nothing; by degrees however he begins to have an imperfect perception of the different objects, and if he remain long enough, he will see them with tolerable distinctness, though the quantity of light be the same as when he entered the room, when they were invisible to him. Sensation often arises from internal causes, without any external impulse. To this source may be referred consciousness, memory, imagination, volition, and other affections of the mind. These are called the internal senses. The senses, whether internal or external, have never been accurately reduced to classes, orders, or genera; the external indeed are generally referred to five orders; namely, seeing, hearing, smelling, tasting, and feeling, or touch. With respect to the four first, the few qualities of external bodies which each perceives may be easily reduced to classes, each of which may be referred to its peculiar organ of sensation, because each organ is so constituted, that it can only be affected by one class of properties; thus the eye can only be affected by light; the ear by the vibrations of the air, and so of the rest. The same organ, whatever be its state, or whatever be the degree of impulse, always gives to the mind a similar sensation; nor is it possible, by any means we are acquainted with, to communicate the sensation peculiar to one organ by means of another. Thus we are incapable, for instance, of hearing with our eyes, and seeing with our ears: nor have we any reason to believe that similar impressions produce dissimilar sensations in different people. The pleasure, however, as well as the pain and disgust, accompanying different sensations, differ very greatly in different persons, and even in the same person at different times; for the sensations which sometimes afford us pleasure, at other times produce disgust. Habit has a powerful influence in modifying the pleasures of sensation, without producing any change in the sensation itself, or in the external qualities suggested by it. Habit, for instance, will never cause a person to mistake gentian or quassia for sugar, but it may induce an appetite or liking for what is bitter, and a disgust for what is sweet. No person perhaps was originally delighted with the taste of opium or tobacco, they must at first be highly disgusting to most people; but custom not only reconciles the taste to them, but they become grateful, and even necessary. Almost every species of sensation becomes grateful or otherwise, according to the force of the impression; for there is no sensation so pleasant, but, that, by increasing its intensity, it will become ungrateful, and at length intolerable. And, on the contrary, there are many which on account of their force are naturally unpleasant, but become, when diminished, highly pleasant. The softest and sweetest sounds may be increased to such a degree as to be extremely unpleasant: and when we are in the steeple of a church, the noise of a peal of bells stuns and confounds our senses, while at a distance their effect is very pleasant. The smell of musk likewise at a distance, and in small quantity, is pleasant; but when brought near, or in large quantity, it becomes highly disagreable. The same may be observed with respect to the objects of the other senses. For a similar reason, many sensations which are at first pleasing, cease to delight by frequent repetition; though the impression remains the same. This is so well known that illustrations are unnecessary. Those who are economical of their pleasures, or who wish them to be permanent, must not repeat them too frequently. In music, a constant repetition of the sweetest and fullest chords, cloys the ear; while a judicious mixture of them with tones less harmonious will be long relished. Those who are best acquainted with the human heart need not be told, that this observation is not confined to music. On the same principle likewise we can account for the pleasure afforded by objects that are new; and why variety is the source of so many pleasures; why we gradually wish for an increase in the force of the impression in proportion to its continuance. The pleasures of the senses are confined within narrow limits, and can neither be much increased nor too often repeated, without being destructive of themselves; thus we are admonished by nature, that our constitutions were not formed to bear the continual pleasures of sense; for the too free use of any of them, is not only destructive of itself, but induces those painful and languid sensations so often complained of by the voluptuary, and which not unfrequently produce a state of mind that prompts to suicide. As the transition from pleasure to pain is natural, so the remission of pain, particularly if it is great, becomes a source of pleasure. There is much truth, therefore, in the beautiful allegory of Socrates, who tells us, that Pleasure and Pain were sisters, who, however, met with a very different reception by mankind on their visit to the earth; the former being universally courted, while the latter was carefully avoided: on this account, Pain petitioned Jupiter, who decreed that they should not be parted; and that whoever embraced the one, obtained also the other. There is a great diversity with respect to the duration of the pleasures of the different senses: some of the senses become soon fatigued, and lose the power of distinguishing accurately their different objects: others, on the contrary, remain perfect a long time. Thus smell and taste are soon satiated; hearing more slowly; while, of all the external senses, the objects of sight please us the longest. We may, however, prolong the pleasures of sense by varying them properly, and by a proper mixture of objects or circumstances which are indifferent, and afford less delight. But the very constitution of our nature limits our enjoyments, and points out the impossibility of perpetual pleasures in this state of our existence. To a person who is thirsty, water is delicious nectar; to one who is hungry, every kind of food is agreeable, and even its smell pleasant; to a person who is hot and feverish, the cool air is highly refreshing. But to the same persons in different circumstances, the same things are not only indifferent, but even disgusting; for instance, a person cannot bear the sight or smell of food, after having satiated himself with it, and perpetual feasting will cloy the appetite of the keenest epicure. I shall conclude this account of the general laws of sensation, by a short recapitulation of those laws. And, in the first place, it may be observed, that the energy or force of any sensation, is proportioned to the degree of attention given by the mind to the external object which causes it. Secondly, A repetition of sensations diminishes their energy, and at last nearly destroys it; but this energy is restored by rest, or the absence of these sensations. Thirdly, The mind cannot attend to two impressions at the same time: so that two sensations never act with the same force at the same instant; the stronger generally overcoming the weaker. The mind, however, can attend to the weaker sensation, in such a manner, as to overpower the stronger, or to render it insensible. Having fully considered the general laws of sensation, I shall now proceed to examine those proper to each sense; and in this examination, two objects will engage our attention. 1. The structure of the organ which receives and transmits the impulse to the mind. 2. The qualities or properties of external bodies, particularly those by which they are fitted to excite sensation. The first sense that we shall examine is touch, which, of all the external senses, is the most simple, as well as the most generally diffused. By means of this sense, we are capable of perceiving various qualities and properties of bodies, such as hardness, softness, roughness, smoothness, temperature, magnitude, figure, distance, pressure, and weight; this sense is seldom depraved; because the bodies, whose properties are examined by it, are applied immediately to the extremities of the nerves, without the intervention of any medium liable to be deranged, as is the case with the eye, and ear. The organ of touch is seated chiefly in the skin, but different parts of this covering possess different degrees of sensibility. The skin consists of three parts. 1. The cutis vera, or true skin, which covers the greatest part of the surface of the body. When the skin is examined by a microscope, we find it composed of an infinite number of papillae, or small eminencies, which seem to be the extremities of nerves, each of which is accompanied by an artery and a vein, so that when the vessels of the skin are injected, the whole appears red. 2. Immediately over the true skin, and filling up its various inequalities, lies a mucous reticulated substance, which has been called by Malpighi, who first described it, rete mucosum. The real skin is white in the inhabitants of every climate; but the rete mucosum is of various colours, being white in Europeans, olive in Asiatics, black in Africans, and copper coloured in Americans. This variety depends chiefly on the degree of light and heat; for, if we were to take a globe, and paint a portion of it with the colour of the inhabitants of corresponding latitudes, we should have an uniform gradation of shade, deepening from the pole to the equator. The diversity of colour depends upon the bleaching power of the oxygen, which, in temperate climates, combines more completely with the carbonaceous matter deposited in the rete mucosum; while, in hotter climates, the oxygen is kept in a gaseous state by the heat and light, and has less tendency to unite with the carbonaceous matter. In proof of this, the skins of Africans may be rendered white by exposure to the oxygneated muriatic acid. Over the rete mucosum is spread a fine transparent membrane, called the cuticle, or scarf skin, which defends the organ of feeling from the action of the air, and other things which would irritate it too powerfully. In some parts of the body this membrane is very thick, as in the soles of the feet, and palms of the hands; and this thickness is much increased by use and pressure. In general, the thinner the cuticle is, the more acute is the sense of touch. This sense is very acute and delicate about the ends of the fingers, where we have the most need of it; but in the lips, mouth, and tongue, it is still more delicate; a galvanic or electrical shock being felt by the tongue, when it is impossible for us to perceive it by the fingers. This sense, like the others, becomes more exquisite when its organ is defended from the action of external bodies; it is on this account that the cuticle becomes so sensible under the end of the nail, which defends it from the action of external objects; and when part of the nail is taken away, we can scarcely bear to touch any thing with this newly exposed part of the skin. When we place our fingers upon the surface of any body, the first sensation we experience is that of resistance, after which the other properties are perceived in a natural order; such as heat or cold, moisture or dryness, motion or rest, distance, and figure or shape. With respect to the diseases of this sense, it is very seldom that it becomes too acute over the whole body; though it frequently does so in particular parts, which may arise from the cuticle being too thin or abraded, or from an inflamed state of the part. It however becomes sometimes obtuse, and indeed almost abolished over the whole body; and this takes place from compression of the brain, and various affections of the nervous power. This diminution is called anaesthesia. The touch becomes deficient, and indeed almost abolished, when the cuticle is injured by the frequent application of hot bodies, or acrid substances: thus the cuticle of the hands of blacksmiths and glassblowers is generally so hard and horny, that they can take up and grasp in their hand pieces of redhot iron with impunity. We generally refer pain to this sense, though it may arise from too violent an impression made upon any of the organs of sense. Pain is an unpleasant sensation, which the mind refers to some part of the body, and very accurately, if any part of the surface is affected, but less so, if it arises from the affection of an internal part. The sensation of pain may arise from any thing which tends to injure the structure of the body, whether that be internal or external; so that it serves as a monitor to put us on our guard, and to induce us to remove any thing which might be injurious to us. This sensation is produced by any thing which punctures, cuts, tears, distends, compresses, bruises, corrodes, burns, or violently stimulates any part of the body. A moderate degree of pain in any part excites the action of the whole body; a greater quantity of blood and nervous energy is determined to the part. A still greater degree of pain brings on inflammation and its consequences, and if it be intense, it will bring on fever, convulsions, delirium, fainting, and even death. The endurance of pain depends much on the strength of mind possessed by the patient, which, in some instances, is such, that the most violent pains are patiently endured; while in other instances, the slightest can scarcely be born. It is a curious circumstance, that a moderate degree of pain, when unaccompanied by fever, often tends to render the understanding more clear, lively, and active. This is confirmed by the experience of people labouring under gout. We have an account of a man who possessed very ordinary powers of understanding, but who exhibited the strongest marks of intelligence and genius in consequence of a severe blow on the head; but that he lost these powers when he recovered from the effects of the blow. Pechlin mentions a young man, who during a complaint originating from worms, possessed an astonishing memory and lively imagination, both of which he nearly lost by being cured. Haller mentions a man who was able to see in the night, while his eyes were inflamed, but lost this power as he got well. All these facts show, that a certain action or energy is necessary for the performance of any of the functions of the body or mind; and whatever increases this action will, within certain limits, increase those functions. Feeling is by far the most useful, extensive, and important of the senses, and may be said indeed to be the basis of them all. Vision would be of very little use to us, if it were not aided by the sense of feeling; we shall afterwards see that the same observation may be applied to the other senses. In short, it is to this sense that we are indebted, either immediately or indirectly, for by far the greatest part of our knowledge; for without it we should not be able to procure any idea with respect to the magnitude, distance, shape, heat, hardness or softness, asperity or smoothness of bodies; indeed, if we were deprived of this sense, it is difficult to say whether we should have any idea of the existence of any external bodies; on the contrary, it seems probable that we should not. LECTURE VI. TASTE AND SMELL. From the sense of touch we proceed naturally to that of taste, for there seems to be less difference between these two senses than between any of the others. The sense of taste appears to be seated chiefly in the tongue; for any sweet substance, such as sugar, applied to any other part of the mouth, scarcely excites the least sensation of taste. The same may be observed with respect to any other sapid body, which, unless it is strongly acrid or irritating, produces no effect on any other part than the tongue; but if it is possessed of much acrimony, it then not only affects the palate, and uvula, but even the oesophagus. The tongue is a muscular substance, placed in the mouth, connected by one end with the adjacent bones and cartilages, while the other end remains free, and easily moveable. The tongue is furnished, particularly on its upper surface, with innumerable nervous papillae, which are much larger than those I described as belonging to the skin. These papillae are of a conical figure, and extremely sensible, forming, without doubt, the true organ of taste; other papillae are found between them, which are partly conical, and partly cylindrical. Over the papillae of the tongue is spread a single mucous, and semipellucid covering, which adheres firmly to them, and serves the purpose of a cuticle. Under these papillae are spread the muscles which make up the fleshy part of the tongue: these are extremely numerous, and by their means the tongue possesses the power of performing a great variety of motions with surprising velocity. The arteries leading to the tongue are extremely numerous; and, when injected with a red fluid, the whole substance appears of a beautiful red. The tongue is likewise furnished with a large supply of nerves, some of which undoubtedly serve to supply its muscles with nervous energy, while others terminate in the papillae, and form the proper organ of taste: this office seems to be performed by the third branch of the fifth pair of nerves. The papillae, before described, are formed or composed of a number of small nerves, arteries, and veins, firmly united together by cellular substance. These papillae are excited to action by the application of any sapid body; in consequence of which they receive a greater supply of blood, become enlarged, and vastly more sensible. The structure of the tongue differs in different animals, which likewise possess corresponding differences with respect to taste. In those quadrupeds, in which it is armed with sharp points, the sense of taste is by no means acute. The same is the case with birds and reptiles, whose tongues are very dry and rough. In a former lecture I took notice of a liquor which is secreted by the glands of the mouth and neighbouring parts, which is called saliva. This liquor acts an important part in the production of taste; it does not differ much from water, excepting by containing a quantity of mucilage; and nothing is sapid, or capable of affecting the sense of taste, unless it is in some degree soluble in this liquor. Hence earthy substances, which are nearly insoluble, have little or no taste. It is not, however, sufficient that the substance be possessed of solubility alone; it is necessary likewise that it should be possessed of saline properties, or, at least, of a kind of acrimony, which renders it capable of stimulating the nervous papillae. Hence it is that those substances which are less saline, and less acrid than the saliva, have no taste. We are capable of distinguishing various kinds of taste, but some of them with less accuracy than others. Among the different kinds of taste, the following have been considered by Haller, and some other physiologists, as primitive: sweet, sour, bitter, and saline. The others have been thought to be compounded of these; for the sense of taste, as well as sight and hearing, is capable of perceiving compound impressions. To these primitive tastes, Boerhaave added alkaline, spirituous, aromatic, and some others. Of these, in different proportions, all the varieties of tastes, which are extremely numerous, are composed. Some tastes are pleasant and agreeable, others disagreeable, and scarcely tolerable: there is, however, a great diversity in this respect experienced by different persons; for the same taste, which is highly grateful to some, is extremely unpleasant to others. But the most pleasant tastes, agreeably to the general laws of sensation, which I described in the last lecture, become gradually less pleasant, and at last disgusting; while, on the contrary, the most disagreeable savours, such as tobacco, opium, and assafoetida, become, by custom, not only tolerable, but highly agreeable. Nature designed this difference of tastes that we might know and distinguish such foods as are salutary; for we may in general observe, that no kind of food which is healthy, and affords proper nutriment to the body, is disagreeable to the taste; nor are any that are ill tasted proper for our nourishment. Those substances, therefore, which possess strong or disagreeable savours, and which, in general, possess a power of producing great changes on our constitution, are to be ranked as medicines, and only to be used when the constitution is deranged; whereas, in general, those which are pleasant, or mild tasted, are proper for nourishing the body. We are therefore excited or prompted to receive nourishment by the pleasant smell or taste of the food; but the avidity with which we take it depends much on the state of the stomach, and likewise on a certain inanition or emptiness; for the coarsest food is grateful to those who are hungry, and whose digestion is good; whereas, to those who have lately eaten, or whose digestive powers are impaired, the most delicate food affords little pleasure. While we are eating, the saliva flows into the mouth more copiously, which excites a more acute sensation of taste. This flow of saliva is likewise frequently excited by the smell or sight of substances agreeable to the taste, which causes an appetite, or desire of eating, similar to that caused by an accumulation of gastric juice in the stomach. In brute animals, who have not, like ourselves, the advantage of learning from each other by instruction, the faculty of taste is much more acute, by which they are admonished to abstain from noxious or unhealthy food. This sense, for the same reason, is more acute in savages than in those who live in civiilsed society, which, whatever perfection it gives to the reasoning faculties of man, certainly diminishes the acuteness of all our senses, partly by affording fewer inducements to exercise them, and partly by our manner of living, and by the application of substances to the organs of sense, which tend to vitiate them, and render them depraved. Taste is modified by age, temperament, habit, and disease; and in this it obeys the general laws of sensation. Children are pleased with the taste of what is sweet, and little stimulating; as we advance in years the taste of more stimulating substances becomes agreeable to us; so that we are admonished by this sense to take into the stomach the kind of nourishment fitted to each period of life. We often, however, counteract this salutary monitor by depraving our sense of taste, by the too free use of vinous or spirituous liquors, which so far deadens the sense of taste, that sweet substances become unpleasant, and nothing but acrid and stimulating things can make an impression on our diminished and vitiated sense of taste. This sense, as well as others, is liable to be diseased. In order that the sense may be perfect, it is necessary that the membrane which envelopes the nervous papillae of the tongue, and serves as a cuticle, should neither be too thick nor too thin, too dry nor too moist. It is necessary likewise that the qualities of the saliva be natural; for alterations in the nature of this liquor affect very much the sense of taste; if it is bitter, which sometimes happens in bilious complaints, all kinds of food have a bitter taste; if it is sweet, the food has a faint and unpleasant flavour; and if it is acid, the food too tastes sour. This sense is seldom observed to be too acute, unless from a vitiated state of the cuticle, or membrane, which covers the tongue: if this has been abraded or ulcerated, then the substances applied to the tongue are more sensibly tasted; in many instances, however, they do not produce an increased sensation of taste, but only of pain. The sense of taste, as well as of touch, may become deficient, from various affections of the brain and nerves; this, however, is not often the case. Some persons have naturally a diminished sense of taste, and this generally accompanies a diminished sense of smell. This sense is frequently diminished in sensibility from a deficiency of saliva, as well as of the proper moisture of the tongue. Hence, in many diseases, it becomes defective, such as fevers, colds, and the like; both from a want of the proper degree of moisture, and from defect of appetite, which, as was before observed, is necessary to the sense of taste. The sense of taste is often diminished by a thickened mucous covering of the tongue, which prevents the application of substances to its nervous papillae. This mucous covering arises from a disordered state of the stomach, as well as from several other affections of the body: hence physicians inspect the tongue, that they may be able to judge of the general state of the body; and next to the pulse, it is undoubtedly the best criterion that we have, as it not only points out the nature and degree of several fevers, but likewise, in many instances, the degree of danger to be apprehended. Having examined the sense of taste, I shall now proceed to consider that of smell; the use of which, like taste, is to enable us to distinguish unwholesome from salutary food; indeed, by this sense, we are taught to avoid what is prejudicial before it reaches the sense of taste, to which it might be very injurious; and thus we are enabled to avoid any thing which has a putrid tendency, which, if received into the stomach, would taint the whole mass of fluids, and bring on speedy dissolution. The seat of this sense is a soft pulpy membrane, full of pores, and small vessels, which lines the whole internal cavity of the nose. On this membrane are distributed abundance of soft nerves, which arise chiefly from an expansion of the first pair of nerves coming from the brain. This membrane is likewise plentifully supplied with arteries; so that by means of this nervous and arterial apparatus, this membrane is possessed of very great sensibility; but the nerves of the nose being almost naked, require a defence from the air, which is continually drawn through the nostrils into the lungs, and forced out again by respiration. Nature has therefore supplied this part with a thick insipid mucus, very fluid at its first separation, but gradually thickening, as it combines with oxygen, into a dry crust, approaching often to a membranous matter. This mucus is poured out, or exhaled, by the numerous minute arteries of the nostrils, and serves to keep the nervous apparatus moist, and in a proper state for receiving impressions, as well as to prevent the violent effects which might arise from the stimulus of the air and other bodies. The sense of smell is the most acute about the middle of the septum of the nose, where the nervous membrane which I have described is thicker and softer, than in the cavities more deeply situated, where it is less nervous and vascular. These parts are not however destitute of the sense. As taste proceeds from the action of the soluble parts of bodies on the nervous papillae of the tongue, so smell is occasioned by minute and volatile particles flying off from bodies, which become mixed with the air, and drawn up with it into the nostrils, where these small particles stimulate or act upon the nerves before described, and produce the sensation which we call smelling. The air therefore, being loaded with the subtile and invisible effluvia of bodies, is, by the powers of respiration, drawn through the nose, so as to apply these particles to the almost naked olfactory nerves, which, as was before observed, excites the sense of smelling. When we wish to smell accurately, we shut the mouth, open the nostrils as wide as possible, and making a strong inhalation, draw up a greater number of these volatile particles, than could be drawn up by the common action of respiration, by which means the olfactory nerves are more stimulated, and produce a stronger sensation. In order that this sense may be enjoyed in perfection, it is necessary that the organ of smell be in a proper state or condition to receive impressions, and that the odorous bodies be likewise in a proper state. With respect to the first, it is necessary that the state of the nerves be sound, and particularly that they be kept in a proper state with respect to moisture. With regard to the odorous bodies, it is necessary, first, that their minute particles should be disengaged, either by heat, friction, fermentation, or other means capable of decomposing those bodies which are the subjects of smell: secondly, that they may be capable of assuming the vaporous or gaseous state, by combining with caloric, or at any rate, that they should remain for a certain time dissolved or suspended in the air: thirdly, that they should not meet with any substance in their way to the nostrils, which is capable of neutralising them, or altering their properties by its chemical action. Notwithstanding all the pains which physiologists have taken to detect the nature of odorous bodies, they have met with but little success. They are so extremely minute as to escape the other senses, and we can only say that they must be composed of particles in an extreme state of division and subtilty, because very small quantities of odorous matter exhale a sufficient quantity of particles to fill a large space. A grain of camphor, musk, or amber exhales an odour which penetrates every part of a large apartment, and which remains for a long time. There is perhaps no substance in nature which is absolutely incapable of being changed from a solid state into that of a fluid or gas, by combining with caloric; though different substances require very different quantities of heat to produce those effects. Those which are with difficulty converted into fluids or gases, are termed fixed, while those which are easily changed are called volatile; though these are only terms of comparison, for there is probably no body which is absolutely fixed, or incapable of being reduced to vapour by the application of a sufficient degree of heat. The odorous property is probably as general as that of being convertible into gas. There is perhaps no body so hard, compact, and apparently inodorous, as to be absolutely incapable of exciting smell by proper methods: two pieces of flint rubbed together, produce a very perceptible smell. Metals which appear nearly inodorous, excite a sensation of smell by friction, particularly lead, tin, iron, and copper. Even gold, antimony, bismuth, and arsenic, under particular circumstances, give out peculiar and powerful odours. The odour of arsenic in its metallic state, and in a state of vapour, resembles that of garlic. The chief means of developing the odorous principles are friction, heat, electricity, fermentation, solution, and mixture. The effect of mixture is very remarkable in the case of lime and muriate of ammoniac, neither of which, before mixture, has any perceptible odour. There is perhaps then no body which is perfectly inodorous, or entirely destitute of smell: for those which have been generally accounted such, may be rendered odorous by some of the methods I have mentioned. Several naturalists and physiologists, such as Haller, Linneus, and Lorri, have attempted to reduce the different kinds of odours to classes, but without any great success; for we are by no means so well acquainted with the physical nature of the odorous particles, as we are with that of light, sound, and the objects of touch; and till we do obtain a knowledge of these circumstances, which perhaps we never shall, it will be in vain to attempt any accurate classification. The division of them into odours peculiar to the different kingdoms, is very inaccurate; for the odour of musk, which is thought to be peculiarly an animal odour, is developed in the solution of gold by some mineral solvents; it is perceptible in the leaves of the geranium moschatum, and some other vegetables. The smell of garlic is possessed by many vegetables, by arsenic, and by toads. The violet smell is perceived in some salts, and in the urine of persons who have taken turpentine. The same may be observed with respect to several other odours. As taste keeps guard, or watches over the passage by which food enters the body, so smell is placed as a sentinel at the entrance of the air passage, and prevents any thing noxious from being received into the lungs by this passage, which is always open. Besides, by this sense, we are invited or induced, to eat salutary food, and to avoid such as is corrupted, putrid, or rancid. The influence of the sense of smell on the animal machine is still more extensive: when a substance which powerfully affects the olfactory nerves is applied to the nostrils, it excites, in a wonderful manner, the whole nervous system, and produces greater effects in an instant, than the most powerful cordials or stimulants received by the mouth would produce in a considerable space of time. Hence in syncope or fainting, in order to restore the action of the body, we apply volatile alkali, or other strong odorous substances, to the nostrils, and with the greatest effect. It may indeed for some time supply the place, and produce the effects, of solid nutriment usually received into the stomach We are told that Democritus supported his expiring life, and retarded, for three days, the hour of death, by inhaling the smell of hot bread, when he could not take nutriment by the stomach. Bacon likewise gives us an account of a man who lived a considerable time without meat or drink, and who appeared to be nourished by the odour of different plants, among which were garlic, onions, and others which had a powerful smell. In short, the stimulus which active and pleasant odours give to the nerves, seems to animate the whole frame; and to increase all the senses, internal and external. The perfection of the organ of smell is different in different animals; some possessing it very acutely; others on the contrary having scarcely any sense of smell. We may in general observe that this sense is much more acute in many quadrupeds than in man: an in them the organ is much more extensive: in man, from the shape of the head, little opportunity is given for extending this organ, without greatly disfiguring the face. In the dog, the horse, and many other quadrupeds, the upper jaw being large, and full of cavities, much more extension is given to the membrane which is the organ of smell, which in some animals is beautifully plaited, in order to give it more surface. Hence a dog is capable of following game, or of tracing his master in a crowd, or in a road where it could not be done by the mere track. Nay, we are told of a pickpocket being discovered in a crowd, by a dog who was seeking its master, and who was directed to the man by the pocket handkerchief of his master, which the pickpocket had stolen. In dogs the sense of smell must be uncommonly delicate, to enable them to distinguish the way their master has gone in a crowded city. The habit of living in society, however, deadens this sense in man as well as taste; for we have the advantage of learning the properties of bodies from each other by instruction, and have therefore less occasion to exercise this sense; and the less any sense is exercised, the less acute will it become; hence it is, that those whom necessity does not oblige to to exercise their senses and mental faculties, and who have nothing to do but lounge about, and consume the fruits of the earth, become half blind, half deaf, and, in general, have great deficiency in the sense of smell. The use of spirituous liquors, and particularly of tobacco in the form of snuff, serves likewise in a remarkable manner to deaden this sense. Savages, however, who are continually obliged to exercise all their senses, have this, as well as others, in very great perfection. Their smell is so delicate and perfect, that it approaches to that of dogs. Soemmering and Blumenbach indeed assert, that in Africans and Americans the nostrils are more extended, and the cavities in the bones lined with the olfactory membrane much larger than in Europeans. I have already observed the powerful effects which some odours have upon the nervous system. There are some which agreeably excite it, and produce a pleasant and active state of the mind, while others, on the contrary, produce the most terrible convulsions, and even fainting. Those particular antipathies with respect to smells, arise sometimes from something in the original constitution of the body, with which we are unacquainted, but generally from the senses having been powerfully and unpleasantly affected by certain odours at an early period of life. The latter may often be cured by resolution and perseverance, but the former cannot. The sense of smell sometimes becomes too acute, either from a vitiated state of the organ itself, which is not often the case; or from an increased sensibility or irritability of the whole nervous system, which is observed in hysteria, phrenitis, and some fevers. This sense is however more often found deficient; and this may arise from a fault in the brain or nerves, which may either proceed from external violence, or from internal causes. A defect of smell often arises from a vitiated state of the organ itself; for instance, if the nervous membrane is too dry, or covered with a thick mucus; of both of which we have an example in catarrh or common cold, where, at the beginning, the nostrils feel unusually dry, but as the disease advances, the pituitary membrane becomes covered with a thick mucus: in both states, the sense of smell is in general deficient, and sometimes nearly abolished. This sense is sometimes depraved, and smells are perceived when no odorous substance is present; or odours are perceived to arise from substances, which are very different from those which we perceive in a sound state. There are many diseases likewise of the nose, and neighbouring parts, which cause a depraved sensation; such as ulcers, cancer, caries; a diseased state of the mouth, teeth, throat, or lungs; or a vitiated state of the stomach, which sometimes exhales a vapour similar to that of sulphureted hydrogen. This sense likewise sometimes becomes depraved from a diseased state of the brain and nerves. LECTURE VII. SOUND AND HEARING. Having in the last lecture examined the senses of taste and smell, I now proceed to that of hearing. As the sense of smell enables us to distinguish the small particles of matter which fly off from the surfaces of bodies, and float in the air, so that of hearing makes us acquainted with the elastic tremors or impulses of the air itself. The sense of hearing opens to us a wide field of pleasure, and though it is less extensive in its range than that of sight, yet it frequently surmounts obstacles that are impervious to the eye, and communicates information of the utmost importance, which would otherwise escape from and be lost to the mind. Sound arises from a vibratory or tremulous motion produced by a stroke on a sounding body, which motion that body communicates to the surrounding medium, which carries the impression forwards to the ear, and there produces its sensation. In other words, sound is the sensation arising from the impression made by a sonorous body upon the air or some other medium, and carried along by either fluid to the ear. Three things are necessary to the production of sound; first, a sonorous body to give the impression; secondly, a medium or vehicle to convey this impression; thirdly, an organ of sense or ear to perceive it. Each of these I shall separately examine. Strictly speaking, sonorous bodies are those whose sounds are distinct, of some duration, and which may be compared with each other, such as those of a bell or a musical string, and not such as give a confused noise, like that made by a stone falling on the pavement. To be sonorous, a body must be elastic, so that the tremors exerted by it in the air may be continued for some time: it must be a body whose parts are capable of a vibratory motion when forcibly struck. All hard bodies, when struck return more or less of a sound; but those which are destitute of elasticity, give no repetition of the sound; the noise is at once produced and dies; while other bodies, which are more elastic and capable of vibration, repeat the sounds produced several times successively. These last are said to have a tone; the others are not allowed to have any. If we wish to give nonelastic bodies a tone, it will be necessary to make them continue their sound, by repeating our blows quickly upon them. This will effectually give them a tone; and an unmusical instrument has often by this means a fine effect in concerts. The effects of a drum depend upon this principle. Gold, silver, copper, and iron, which are elastic metals, are sonorous; but lead, which possesses scarcely any elasticity, produces little or no tone. Tin, which in itself has very little more sound than lead, highly improves the tone of copper when mixed with it. Bell metal is formed of ten parts of copper, and one of tin. Each of these is ductile when separate, though tin is only so in a small degree, yet they form when united a substance almost as brittle as glass, and highly elastic. So curious is the power of tin in this respect, that even the vapour of it, when in fusion, will give brittleness to gold and silver, the most ductile of all metals. Sonorous bodies may be divided into three classes; first, bells of various figures and magnitudes: of these such as are formed of glass have the most pure and elegant tones, glass being very elastic, and its sound very powerful; secondly, pipes of wood or metal; thirdly, strings formed either of metallic or animal substances. The sounds given by strings are more grave or more acute according to the thickness, length, and tension of the strings. Air is universally allowed to be the ordinary medium of sound, or the medium by which sounds are propagated from sonorous bodies, and communicated to the ear. This may be shown by an experiment with the air pump; also with the condenser. But though air is the general vehicle of sound, yet sound will go where no air can convey it; thus the scratching of a pin at the end of a long piece of timber may be heard by an ear applied at the other end, though it could not be heard at the same distance through the air. On this account it is that sentinels are accustomed to lay their ears to the ground, by which means they can often discover the approach of cavalry, at a much greater distance than they can see them. For the same reason two stones being struck together under water, may be heard at a much greater distance by an ear placed under water likewise, than it can be heard through the air. Dr. Franklin, who several times made this experiment, thinks that he has heard it at a greater distance than a mile. This shows that water is better adapted to convey sound than air. When an elastic body is struck, that body, or some part of it, is made to vibrate. This is evident to sense in the string of a violin or harpsichord, for we may perceive by the eye, or feel by the hand, the trembling of the strings, when by striking they are made to sound. If a bell be struck by a clapper on the inside, the bell is made to vibrate. The base, of the bell, is a circle, but it has been found that by striking any part of this circle on the inside, that part flies out, so that the diameter which passes through this part of the base will be longer than the other diameter. The base, by the stroke, is changed into an ellipse or oval, whose longer axis passes through the part against which the clapper is struck. The elasticity of the bell restores the figure of the base, and makes that part which was forced out of its place, return back to its former situation, from which the same principle throws it out again; so that the circular figure of the bell will be again changed to an ellipse, only now the shorter axis will pass through the part which was first struck. The same stroke, which makes the bell vibrate, occasions the sound, and as the vibrations decay, the sound grows weaker. We may be convinced by our senses that the parts of the bell are in a vibratory motion while it sounds. If we lay the hand gently on it, we shall easily feel this tremulous motion, and even be able to stop it, or if small pieces of paper be put upon the bell, its vibrations will put them in motion. These vibrations in the sounding body will cause undulations or waves in the air; and, as the motions of one fluid may often be illustrated by those of another, the invisible motions of the air have been properly enough compared to the visible waves of water produced by throwing a stone therein. These waves spread themselves in all directions in concentric circles, whose common centre is the spot where the stone fell, and when they strike against a bank or other obstacle, they return in the contrary direction to the place from whence they proceeded. Sound in like manner expands in every direction, and the extent of its progress is in proportion to the impulse on the vibrating chord or bell. Such is the yielding nature of fluids, that when other waves are generated near the first waves, and others again near these, they will perform their vibrations among each other without interruption; those that are coming back will pass by those that are going forwards, or even through them, without interruption: for instance, if we throw a stone into a pond, and immediately after that, another, and then a third, we shall perceive that their respective circles will proceed without interruption, and strike the banks in regular succession. The atmosphere in the same manner possesses the faculty of conveying sounds in the most rapid succession or combination, as distinctly as they were produced. It possesses the power not only of receiving and propagating simple and compound vibrations in direct lines from the voice, or an instrument, but of retaining and repeating sounds with equal fidelity after repeated reflection and reverberation, as is evident from the sound of a French horn among hills. Newton was the first who attempted to demonstrate that the waves or pulses of the air are propagated in all directions round a sounding body, and that during their progress and regress they are twice accelerated and twice retarded, according to the law of a pendulum vibrating in a cycloid. These propositions are the foundation of almost all our reasoning concerning sound. When sonorous bodies are struck, they, by their vibration, excite waves in the air, similar to those caused by a stone thrown into water; some parts of these waves entering the ear, produce in us that sensation which we call sound. How these pulsations act upon the auditory nerve, to produce sound, we know not, as we see no necessary connexion between the pulses and the sensation, nor the least resemblance between them; but we can trace their progress to a certain extent, which I shall now endeavour to do. The external part of the ear is called the auricle, or outward ear, which is a cartilaginous funnel, connected to the bones of the temple, by means of cellular substance, and likewise by its own proper ligaments and muscles. This cartilage is of a very compound figure, being a kind of oval, marked with spirals standing up, and hollows interposed, to which other hollows and ridges correspond on the opposite side. The outer eminence is called helix. Within the body of the cartilage arises a forked eminence called antihelix, which terminates in a small and short tongue called antitragus. The remaining part of the ear, called the concha or shell, is anteriorly hollow, but posteriorly convex, growing gradually deeper; with a crooked line or ridge running along its middle, which is immediately joined to the meatus auditorius, or entrance into the ear; before which stands a round moveable appendix, which serves as a defense, called tragus. Against this funnel of the ear the sonorous waves strike, and its different parts are most admirably contrived to reflect them all into the meatus auditorius: if it would not occupy too much time, it might be shown, that all these curves and spirals are contrived in the best manner possible, and with a most perfect knowledge of the geometry of sounds, to reflect the sonorous pulses accurately, and in the greatest possible quantity, into the ear. This external part of the ear is differently formed in different animals; and admirably suited to their various situations and habits. In man it is close to the head, but so formed as to collect the various pulses with great accuracy; in other animals it is more simple, where less accuracy is required, but it is, in general, much larger, having the appearance of an oblong funnel; and this gives them a greater delicacy of hearing, which was necessary for them. In animals which are defenceless and timid, and which are constantly obliged to seek their safety in flight, the opening of this funnel is placed behind, that they may better hear the noises behind them. This is particularly instanced in the hare. Beasts of prey have this opening before, that they may more easily discover their prey; as the lion and tiger. Those that feed on birds have the opening directed upwards, as the fox; and it is inclined downwards in animals, such as the weasel, which seek their prey on the earth. To this external part of the ear, which I have described, is connected the meatus auditorius, or passage to the internal ear, which is somewhat of a compressed cylindrical figure, lessening as it bends inwards: a considerable part of it is bony, and it is bent towards the middle. Across this passage, at its inner extremity, is stretched a thin membrane, called membrana tympani. Upon the surface of this membrane, the sonorous waves, which have been directed inwards by the external ear, strike, and cause it to vibrate like the membrane of a drum. This membrane is stretched over a cavity in the bone, called the os petrosum, which cavity is called the tympanum, or drum of the ear, which is of a rounded figure, divided in its middle by a promontory, and continued backwards to the cells of the mastoid bone. Besides this continuation of the tympanum into the mastoid cells, it has a free communication with the mouth, by means of a tube I shall soon describe. Within this cavity of the tympanum are placed four small bones, which facilitate the hearing: the first is the malleus or hammer, so called from its shape: the upper part of its round head rests upon the concavity of the tympanum, from whence the handle is extended down, along the membrane of the tympanum; this bone has several muscles, which move it in different directions, and cause it to stretch or brace the membrana tympani, when we wish to hear with accuracy. Connected with the malleus is another small bone, called the incus, or anvil, which is connected with another, called the stapes, or stirrup, from its shape. These two bones are connected by a small oval shaped bone, called os orbiculare, placed between them: the whole forming a little chain of bones. The stapes, or stirrup, has its end of an oval shape, which fits a small hole called fenestra ovalis, in that part of the ear called the labyrinth, or innermost chamber of the ear. The labyrinth consists of three parts; first, the vestibule, which is a round cavity in a hard part of the os petrosum; secondly, the semicircular canals, so called from their shape, which however is not exactly semicircular; thirdly, the cochlea, which is a beautifully convoluted canal, like the shell of a snail. This part has a round cavity called fenestra rotunda, which is covered with a thin elastic membrane, and looks into the tympanum. The vestibule, semicircular canals, and cochlea, the whole of which is called the labyrinth, form one cavity, which is filled with a very limpid fluid resembling water, and the whole lined with a fine delicate membrane, upon which the auditory nerve is expanded, like the retina upon the vitreous humor of the eye. This beautiful apparatus was only lately discovered by an Italian physician, Scarpa. The auditory nerve is a portion of the seventh pair, which is called the portio mollis or soft portion. There is one part of the ear still to be described, namely, the Eustachian tube, so called from Eustachius, the anatomist, who first described it. This tube opens by a wide elliptical aperture into the tympanum behind the membrane; the other end, which gradually grows wider, opens into the cavity of the mouth. By this canal the inspired air enters the tympanum to be changed and renewed, it likewise serves some important purpose in hearing, with the nature of which we are yet unacquainted. It is certain that we can hear through this passage, for if a watch be put into the mouth, and the ears stopped, its ticking may be distinctly heard; and in several instances of deafness, this tube has been found completely blocked up. The waves, which have been described as propagated in the air, in all directions from the sounding body, enter the external cartilaginous part of the ear, which, as has before been observed, is admirably fitted for collecting and condensing them. As soon as these pulses excite tremors in the membrane of the tympanum, its muscles stretch and brace it, whence it becomes more powerfully affected by these impulses. It is on this account that we hear sounds more distinctly when we attend to them, the membrane being then stretched. A tremulous motion, being excited in this membrane, is communicated to the malleus annexed to it, which communicates it to the incus, by which it is propagated through the os orbiculare to the stapes, which imparts this tremulous motion through the foramen ovale to the fluid contained in the labyrinth. This tremor is impressed by the waves excited in this fluid, on every part of the auditory nerve in the labyrinth. The use of the foramen rotundum, or round hole, before described, is probably the same as that of the hole in the side of a drum; it allows the fluid in the labyrinth to be compressed, otherwise it could not vibrate. If the organization is sound, and tremors are communicated to the auditory nerve, they are in some way or other conveyed to the mind, but in what manner we cannot tell. Nature has hid the machinery by which she connects material and immaterial things entirely from our view, and if we try to investigate them, we are soon bewildered in the regions of hypothesis. Tremors may however be communicated to the auditory nerve in a different manner from what I have described. If a watch be put between the teeth, and the ear stopped, tremors will be communicated to the teeth, by them to the bones of the upper jaw, and by these to the auditory nerve. In this way a person born deaf, and having no power of hearing through the medium of the air, may become sensible of the pleasures of music. That sound may be propagated by vibrations, independent of pulses of the air, is evident from the experiment with the string and poker. There is, strictly speaking, no such thing existing as sound; it being only a sensation of the mind, caused by tremors of the air, or vibrations of the sounding body. In order to understand more clearly how pulses, or waves are caused by the vibration of bodies, and the manner in which vibrating bodies are affected, I shall just enumerate some of the properties of pendulums, which however I shall not stop to demonstrate here, as that would consume much time. When two pendulums vibrate which are exactly of the same length, their vibrations are performed in equal times; if they set out together to describe equal arcs, they will agree together in their motions, and the vibrations will be performed in equal times. But if one of these pendulums be four times as long as the other, the vibrations of the longer will be twice as slow as those of the shorter; the number of vibrations being as the square roots of their lengths. A pendulum is fixed to one point, but a musical string is extended between two points, and in its vibrations may be compared to a double pendulum vibrating in a very small arc, hence we see how strings of different lengths may agree in their motions after the manner of pendulums; but we must observe that it is not necessary to quadruple the length of a musical string, in order to make the time of vibration twice as long; it will be sufficient merely to double it. We know that from whatever height a pendulum falls on one side, to the same height will it rise on the other. In the same manner will an elastic string continue to vibrate from one side to the other for some time, till its motion be destroyed by the resistance of the air, and friction about its fixed points, and each of its small vibrations, like those of a pendulum, will, for the same reason, be performed in times exactly equal to each other. Thus we gain from the analogy between a pendulum and a musical string, a more adequate conception of a subject which was never understood till this analogy was discovered. It explains to us why every musical string preserves the same pitch from the beginning to the end of its vibration; or as long as it can be distinguished by the ear; and why the pitch remains still unvaried whether the sound is loud or soft, and all this because the vibrations of the same pendulum whether they are longer or shorter, when compared among themselves, are found to be all performed in equal times till the pendulum be at rest, the difference of the space, which is moved over, compensating for the slowness of the motion till its decay. To illustrate this subject still further, suppose we have a piece of catgut stretched between two pins; I lay hold of it in the middle and pull it sideways; I let it go, and you will observe that it first straightens itself or returns to its original position. This depends on the elasticity of its particles, which tend to reunite when they have been separated by an external force, just in the same way that the particles of a piece of caoutchouc or Indian rubber attract each other when pulled asunder; and this force not only enables the string to restore itself to its former situation, but will carry it nearly to an equal distance on the other side, just in the same manner as a ball falling down an inclined plane will rise nearly to the same height up another, or a pendulum will rise nearly to the height from which it fell. In this way will a string move backwards and forwards, till friction and the resistance of the air have destroyed the velocity which it acquired by the force of elasticity. It is obvious that when a string is thus let fly from the finger, whatever be its own motion, such will also be the motion of the particles of the air which fly before it: the air will be driven forwards, and by that means condensed. When this condensed air expands itself, it will expand not only towards the string, but as its elasticity acts in all directions, it will also expand itself forwards and condense the air that is beyond it, this last condensed air, by its expansion, will produce the same effect on the air that lies still further forwards, and thus the motion produced in the air, by the vibration of the elastic string, is constantly carried forwards and conveyed to the ear. It will be proper however to observe, that these pulses are sometimes produced without any such vibration of the sounding body, as we find it in musical strings and bells. In these cases we have to discover by what cause these condensations or pulses may be produced without any apparent vibrations in what is considered as the sounding body. We have two or three instances of this kind; one in wind instruments, such as the flute or organ pipe; another in the discharge of a gun. In an organ, or flute, the air, which is driven through the pipe, strikes against the edge of the lips of the instrument in its passage, and by being accumulated there, is condensed, and this condensation produces waves or pulses in the air. When a gun is discharged, a great quantity of air is produced, by the firing of the gunpowder, which being violently propelled from the piece, condenses the air that encompasses the space where the expansion happens; for whatever is driven out from the space where the expansion is made will be forcibly driven into the space all around it. This condensation forms the first pulse, and as this, by its elasticity, expands again, pulses of the same sort will be produced and propagated forwards. There is likewise another curious instance of the production of sound, when a tube is held over a stream of inflamed hydrogen gas issuing out of a capillary tube in a bottle. Sounding bodies propagate their motions on all sides, directly forwards, by successive condensations and rarefactions, so that sound is driven in all directions, backwards and forwards, upwards and downwards, and on every side; the pulses go on succeeding each other like circles in disturbed water. Sounds differ from each other both with respect to their tone and intensity: in respect to their tone, they are distinguished into grave and acute: in respect to their intensity, they are distinguished into loud and low, or strong and weak. The tone of a sound depends on the velocity with which the vibrations are performed, for the greater the number of vibrations in a given time, the more acute will be the tone, and on the contrary, the smaller the number, the more grave it will be. The tone of a sound is not altered by the distance of the ear from the sounding body; but the intensity or strength of any sound depends on the force with which the waves of the air strike the ear; and this force is different at different distances; so that a sound which is very loud when we are near the body that produces it, will be weaker if we are further from it, though its tone will suffer no alteration; and the distance may be so great that we cannot hear it at all. It has been demonstrated, that the intensity of sound at different distances from the sounding body is inversely as the square of the distance. Sound moves with the same velocity at all distances from the sounding body, otherwise it would not produce the same tone at all distances. Sounds of different tones likewise move with the same velocity. This is evident from a peal of bells being heard in the same order in which they are rung, whether we are near, or at a distance. It is likewise found that sounds of the same tone but of different intensities are propagated with the same velocity. A low sound cannot indeed be heard so far as a loud one; but sounds, whether low or loud, will be conveyed in an equal time to any equal distance at which they can both be heard. The report of a cannon does not move faster, or pass over a given space sooner, than the sound of a musical string. The principal cause of the decay of sound is the want of perfect elasticity in the air: whence it happens that every subsequent particle has not the entire motion of the preceding particle communicated to it, as is the case with equal and perfectly elastic bodies; consequently the further the motion is propagated, the more will the velocity with which the particles move be diminished; the condensation of the air will be diminished also, and consequently its effect on the ear. That the want of perfect elasticity in the air is the principal cause of the decay of sound, appears from this, that sounds are perceived more distinctly when the north and easterly winds prevail, at which time the air is dry and dense, as appears from the hygrometer and barometer; and, of course, the air in this state must be more elastic, for the vapours diffused through the atmosphere, unless dilated by intense heat, diminish the spring of the air. That sound is not propagated to all distances instantaneously, but requires a sensible time for its passage from one place to another, is evident from the discharge of a gun at a distance; for the report is not heard till some time after the flash is seen. Light moves much more swiftly than sound; it comes from the sun in eight minutes, which is at the rate of 74,420 leagues in a second; so that the velocity of light may be considered as instantaneous, at any distance on the earth; and, as sound takes up a considerable time in its passage, the interval between the flash and the report of the gun shows the space it passes over in a given time, which is found to be 1142 feet in a second; so that if three seconds elapse between the time when we see the flash and hear the report of the gun, it must be distant 1142 yards. From experiments that have been made at different times, by various philosophers, we may collect the following results. First, That the mean velocity of sound is a mile in about 4 3/4 seconds, or 1142 feet in a second of time. Secondly, That all sounds, whether they be weak or strong, have the same velocity. Thirdly, That sound moves over equal spaces in equal times, from the beginning to the end. The tone of a musical string, or a bell, appears continuous. This depends upon a law of sensation, formerly mentioned, namely, that impressions made upon any of the organs of sense do not immediately vanish, but remain some time; and we hear sound continuous from these vibrations, for the same reason that we hear it continuous when we draw a stick quickly along a rail, or a quill along the teeth of a comb; the vibrations succeed each other so quickly that we hear the succeeding before the effect of the preceding is worn off; though it must be evident that the impression produced by each pulse or wave of the air is perfectly distinct and insulated. The act of combining sounds in such a manner as to be agreeable to the ear, is called music. This art is usually divided into melody and harmony. An agreeable succession of sounds is called melody; but when two or more sounds are produced together, and afford an agreeable sensation, the effect is called harmony. When two sounds are produced together, and afford pleasure to the sense of hearing, the effect is called a concord; but when the sensation produced is harsh or disagreeable, it is called a discord. These different effects seem to depend upon the coincidence of the vibrations of the two strings, and consequently on the coincidence of the pulses which they excite in the air. When the strings are equally stretched, and of the same length and thickness, their vibrations will always coincide, and they produce a sound so similar to each other, that it is called unison, which is the most perfect concord. When one string is only half the length of the other, the vibrations coincide at every second vibration of the shorter string: this produces a compound sound, which is more agreeable to the ear than any other, except the unison; this note, when compared with the tone produced by the longer string, is called the octave to it, because the interval between the two notes is so divided by musicians that from one to the other they reckon eight different tones. If the strings be of the length, two and three, the coincidence of the pulses will happen less frequently, viz. at every third vibration of the shorter string, and the concord will be less perfect. This forms what is called a fifth. The less frequent the coincidence of the vibrations, the less perfect will be the concord, or the less pleasure will it afford to the mind; till the vibrations coincide so seldom, that the sound produced by both strings at once is harsh and disagreeable, and is called a discord. The effects of music upon the mind, the power by which it moves the heart, touches the passions, and excites sometimes the highest pleasure, and sometimes the deepest melancholy, depend upon melody. By a simple melody the ignorant are affected as well as those skilled in music. The pleasures arising from harmony or a combination of sounds are acquired rather than natural. Its pleasures are the result of experience and knowledge in music; music affords a source of innocent and inexhaustible pleasure, but its effects are different on different persons: some are enthusiastically fond of it, while others hear the sweetest airs with a listlessness bordering upon indifference. This has been supposed to depend on a musical ear, which is not given by nature to all. The cause of this difference is by no means evident. It does not depend on the delicacy of the sense of hearing, for there are some persons half deaf, who have the greatest relish for music; while others who have a very acute sense of hearing have no relish for music. In some instances I think a musical ear has been acquired where it did not seem originally to exist. The force of sound is increased by the reflection of many bodies, particularly such as are hard or elastic, which receive the waves or pulses of the air and reflect them back again; these reflected pulses, striking the ear along with the original, strengthen the original sound. Hence it is, that the voice of a speaker is louder, and more distinctly heard, in a room than in the open air. I said that these reflected sounds entered the ear at the same time with the original: this however is not strictly the case, for they must enter the ear after the original, because the sound has a greater space to move over: but they enter the ear so quickly after the original that our sense cannot distinguish the difference. If however the reflecting body should be placed at such a distance, that the reflected sound should enter the ear some considerable or sensible time after the original, an echo or distinct sound would be heard. It appears from experiment that the ear of an experienced musician can only distinguish such sounds as follow each other at the rate of nine or ten in a second, or any lower rate; and therefore that we may have a distinct perception of the direct and reflected sound, there should at least be an interval of 1/9 of a second; but in this time sound passes over one hundred and twenty seven feet, and consequently, unless the space between the sounding body and the reflecting surface, added to that between the reflecting surface and the ear, be greater than one hundred and twenty seven feet, no echo will be heard, because the reflected sound will enter the ear so soon after the original, that the difference cannot be distinguished; and therefore it will only serve to augment the original sound. From what has been said, it is evident, in order that a person may hear the echo of his own voice, that he should stand at least sixty three, or sixty four feet from the reflecting obstacle, so that the sound may have time to move over at least one hundred and twenty seven feet before it come to his ear, otherwise he could not distinguish it from the original sound. But though the first reflected pulses may produce no echo, both on account of their being too few in number, and too rapid in their return to the ear; yet it must be evident that the reflecting surface may be so formed, that the pulses, which come to the ear after two or more reflections, may, after having passed over one hundred and twenty seven feet or more, arrive at the ear in sufficient numbers to produce an echo, though the distance of the reflecting surface from the ear be less than the limit of echoes. This is instanced by the echoes that we hear in several caves or caverns. The sense of hearing is more apt to be vitiated or diseased than any of the other senses, which indeed is not surprising, when we consider that its organ is complex, consisting of many minute parts, which are apt to be deranged. It sometimes becomes too acute, and this may arise either from too great an irritability of the whole nervous system, which often occurs in hysteria, also in phrenitis, and some fevers; or from an inflamed state of the ear itself. The sense of hearing becomes diminished, and often entirely abolished; and this may arise from various causes, such as an original defect in the external ear, or the meatus auditorius, or both; the meatus auditorius is often blocked up with wax or other substances, which being removed, the hearing becomes perfect. Deafness may likewise arise from a rigidity of the membrane of the tympanum, from its being erodedor ruptured, or from an obstruction of the Eustachian tube. It may likewise arise from a paralysis or torpor of the auditory nerve, or from some diseased state of the labyrinth, or from a vitiated state of the brain and nerves. There is a kind of nervous deafness which comes on suddenly, and often leaves the patient as suddenly. There are various instances, however, in which the membane of the tympanum has been lacerated or destroyed, without a total loss of the sense of hearing, or indeed any great diminution of it. A consideration of these circumstances induced Mr. Astley Cooper to think of perforating it, in cases of deafness arising from a permanent obstruction of the Eustachian tube, and he has often performed this operation with great success. Of this he has given an account in the last part of the Philosophical Transactions. This operation ought however only to be performed in case of the closure of the Eustachian tube. Cases of this kind may be distinguished by the followingcriteria. If a person on blowing the nose violently, feel a swelling in the ear, from the membrane of the tympanum being forced outwards, the tube is open; and though the tube be closed, if the beating of a watch placed between the teeth, or pressed against the side of the head, cannot be heard, the operation cannot relieve, as the sensibility of the auditory nerve must have been destroyed. In a closed Eustachian tube, there is no noise in the head, like that accompanying nervous deafness. There is one species of deafness, which occurs very frequently, and happens generally to old persons, though sometimes to the delicate and irritable in the earlier periods of life. Anxiety and distress of mind have been known to produce it. Its approach is generally gradual, the patient hears better at one time than at another; a cloudy day, a warm room, agitated spirits, or the operation of fear, will produce a considerable diminution in the powers of the organ. In the open air the hearing is better than in a confined situation; in a noisy, than in a quiet society; in a coach when it is in motion, than when it is still. A pulsation is often felt in the ear; a noise resembling sometimes the roaring of the sea, and at others the ringing of distant bells is heard. This deafness generally begins with a diminished secretion of the wax of the ear, which the patient attributes to cold. It may be cured, particularly at its commencement, by the application of such stimulants as are capable of exciting a discharge from the ceruminous glands; for which purpose thev should be introduced into the meatus auditorius. In some cases of this kind, where the auditory nerve has been in some degree torpid, or rather perhaps where there has been a kind of paralysis, or want of action, in the muscles which brace the membrane of the tympanum, and keep the chain of bones in their proper state; a person has not been able to hear, except during a considerable noise. Willis mentions the case of a person who could only hear when a drum was beaten near her; and we are told of a woman who could not hear a word except when the sound of a drum was near, in which case she could hear perfectly well. When she married, her husband hired a drummer for his servant. In instances of this kind the noise probably excites the action of the torpid muscles, which then put the apparatus in a proper condition to hear. LECTURE VIII. VISION. In order to understand properly the theory of vision, it will be necessary to premise an anatomical description of the eye: but I shall content myself with as short a one as will suffice to explain the effects it produces on the rays of light, so as to produce the distinct vision of an object. The shape of the eye is nearly spherical; it is composed of several coats or tunics, one within another; and is filled with transparent humours of different densities. The proper coats of the eye are reckoned five in number; viz. the sclerotica, cornea, choroides, iris or uvea, and the retina. After the tunica conjunctiva, or adnata, (a membrane, which, having lined the eyelids in the manner of a cuticle, surrounds the anterior part of the globe) is removed, we perceive a white, firm, membrane, called the sclerotica, which takes its rise from that part of the globe where the optic nerve enters, and surrounds the whole eye, except a little in the fore part; which fore part has a membrane, immediately to be described, called the cornea. The tunica sclerotica, viewed through the conjunctiva, forms what is called the white of the eye. Some anatomists have supposed that this coat is a continuation of the dura mater, which surrounds the optic nerve; but later observations have shown this opinion to be ill founded. The tunica sclerotica consists of two layers, which are with difficulty separated. The next coat is the cornea, so called from its resemblance to transparent horn; it arises where the sclerotic coat ends, and forms the fore part of the eye. The cornea is a segment of a lesser sphere than the rest of the eye, and consequently makes it more prominent on the fore part: it is transparent, and firmly connected by its edges to the sclerotica. Immediately adherent to the sclerotica, within, is the choroides, which takes its rise from that part of the eye where the optic nerve enters, and accompanies the sclerotica to the place where it is joined to the cornea; here it is very closely connected to the sclerotica, where it forms that annulus, called ligamentum ciliare; then leaving the sclerotic coat, it is turned inwards, and surrounds the crystalline lens; but as this circle, where it embraces the crystalline, is much narrower than where the membrane leaves the sclerotic coat, it becomes beautifully corrugated, which folds or corrugations have been, by the more ancient anatomists, improperly called ciliary processes. To the same part of the choroid coat, where the ciliary ligament begins, is fixed a moveable and curious membrane, called the iris; this membrane has a perforation in the middle, called the pupil, for the admission of the rays of light. The iris is composed of two kinds of fibres: those of the one sort tend, like the radii of a circle, towards its centre, and the others form a number of concentric circles round the same centre. The pupil is of no constant magnitude, for when a very luminous object is viewed, the circular fibres of the iris contract, and diminish its orifice; and, on the contrary, when objects are dark and obscure, those fibres relax, and suffer the pupil to enlarge, in order to admit a greater quantity of light into the eye: it is thought that the radial fibres also assist in enlarging the pupil. The iris is variously coloured in different persons, but according to no certain rule; though in general, they who have light hair, and a fair complexion, have the iris blue or grey; and, on the contrary, they whose hair and complexion are dark, have the iris of a deep brown; but whether this difference in colour occasions any difference in the sense, is not yet discovered. In the human eye the whole choroid coat, and even the interior surface of the iris or uvea, is lined with a black mucus; this mucus, or as it is called, pigmentum, is darkest in young persons, and becomes more light coloured as we advance in years. In many animals, but more particularly those which catch their prey in the night, this pigmentum is of a bright colour: its use will appear afterwards. The last, and innermost coat of the eye, is the retina, it differs much from the above mentioned coats, being very delicate and tender. It is nothing but an expansion of the medullary part of the optic nerve, which is inserted into each eye, nearer the nose, and a little higher, than the axis. This coat has been thought by many to end where the choroides, going inwards, towards the axis of the eye, forms the ciliary ligament; Dr. Monro thinks that it is not continued so far, and we cannot see with what advantage it could have been continued to the ciliary ligament, since none of the rays of light, passing through the pupil, could fall upon that part of it. In the middle of the optic nerve is found the branch of an artery, from the internal carotid, which is diffused and ramified in a beautiful manner along the retina. From this artery, a small branch goes through the middle of the vitreous humour, and giving off branches on every side, expands itself upon the capsule of the crystalline lens. We shall now consider the humours of the eye, which are three in number, the aqueous, the crystalline, and the vitreous; all transparent, and in general colourless; but of different densities. The aqueous humour, so called from its resemblance to water, fills up all the space between the cornea and the crystalline humour. It is partly before and partly behind the uvea, and is divided by that membrane into two parts, which are called the chambers of the aqueous humour; which chambers communicate with each other by means of the pupil. The next humour is the crystalline; it is situated between the aqueous and vitreous humours, and is connected to the choroid coat by the ciliary ligament: it is not the least of all the humours, as has been generally supposed, the aqueous and it being of equal weights; but its substance is more firm and solid than that of the other humours: its figure is that of a double convex lens; but the fore part next the pupil is not so convex as its other side, which is contiguous to the vitreous humour; the diameter of the sphere, of which its anterior segment is a part, being in general about seven or eight lines, whereas the diameter of the sphere, of which its posterior segment forms a portion, is commonly only about five or six lines. It is covered with a fine transparent capsule, which is called arachnoides. This humour is situated exactly behind the pupil, but not in the centre of the eye, as was supposed by Vesalius, being a good deal nearer its forepart. The convexity of its posterior surface is received into an equal concavity of the vitreous humour. It is not of an equal density throughout, but is much more hard and dense towards its centre than externally, the reason of which will appear hereafter. Till we arrive at about our thirtieth year, this humour continues perfectly transparent, and colourless; about that time it generally has a little tinge of yellow, and this colour increases with age. The third humour of the eye, is the vitreous; it is the largest of all the humours, filling up the whole of that part of the eye which lies behind the crystalline humour. It is thicker than the aqueous, but thinner than the crystalline humour; on its back part is spread the retina, and in the middle of its fore part is a small cavity, in which the whole posterior surface of the crystalline lens lies; this humour is also enclosed in a very fine capsule, called tunica vitrea; this capsule at the edge of the crystalline humour is divided into two membranes, of which the one is continued over the whole anterior surface of the vitreous humour, and lines that cavity into which the back part of the crystalline is received; the other passes over the crystalline humour, and covers all its fore part, by which means these two humours are closely connected together. The weights of the aqueous, crystalline, and vitreous humours in a human eye, are, according to the accurate Petit, at a medium, to each other, as 1, 1, and 25. It was thought necessary to premise this general description of the structure of the eye, in order that what we are going to add in the remaining part of this Lecture may be the more easily comprehended. A more distinct idea will perhaps be had from a contemplation of the following figure, which represents the section of an eye by a vertical plane passing through its centre. [FIGURE] EXPLANATION. NOO represents the optic nerve. The outmost line ALLB represents the sclerotic coat, and the part ACB the transparent cornea. The line ALLB, immediately within the former, represents the choroides; the part APB is the iris or uvea, in which the hole at P is the pupil. The line FOOG is the retina. The cavity ACBEMDA is the aqueous humour. DE is the crystalline lens or humour. The space DFOOGE, lying behind the crystalline, represents the vitreous humour. BE and AD is the ligamentum ciliare. _Nature and Properties of Light._ After this short description of the human eye, I shall next proceed to take notice of some of the properties of light; but shall confine myself to such as are absolutely necessary for explaining the phenomena of vision, as far as that can be done from optical principles. 1. It is, I believe, generally at present agreed, that light consists of exceedingly small particles of matter, projected with great velocity in all directions from the luminous or radiant body. This hypothesis, to which no solid objection has yet been made, appears to be more simple than any other; and is so consistent with all the phenomena yet observed, that we have great reason to think it true: however, as it is not absolutely and directly demonstrated, it may have been wrong in optical writers to have given this hypothesis (for it can only be called a hypothesis) as a definition of light. 2. The space through which light passes is, by opticians, called a medium, and it is observed, that, when light passes through a medium, either absolutely void, or containing matter of an uniform density, and of the same kind, it always proceeds in straight lines. 3. Those rays of light which come directly from a luminous body to the eye, only give us a perception of light; but when they fall upon other bodies, and are from them reflected to the eye, they give us an idea or perception of those bodies. 4. When a ray of light passes out of one medium into another of different density, it is bent out of its course, and is said to be refracted. We must, however, except those rays which fall in a direction perpendicular to the surface of the refracting medium; as the refractive force acts in the same direction in which those rays move, they will not be turned out of their course, but proceed in the same direction they had before they entered the refracting medium. When a ray passes out of a rarer into a denser medium, it will be refracted, or bent towards a line which is perpendicular to the surface which separates the media at the point where it falls; but when it passes out of a denser into a rarer medium, it will be bent from the perpendicular. 5. Whenever the rays, which come from all the points of any object, meet again in so many points, after they have been made to converge by refraction, there they will form the picture of the object, distinct, and of the same colours, but inverted. This is beautifully demonstrated by a common optical instrument, the camera obscura. If a double convex lens, be placed in the hole of a window shutter in a dark room, and a sheet of white paper be placed at a certain distance behind the lens; a beautiful, but inverted picture of the external objects will be formed: but if the paper be held nearer, or more remote than this distance, so that the rays from each point shall not meet at the paper, but betwixt it and the lens, or beyond the paper, the picture will be indistinct and confused. _Of the Manner in which Vision is performed._ From the just mentioned properties of light, and the description we have given of the eye, it will not be difficult to explain the theory of vision, so far as it depends upon optical principles. For the eye may, with great propriety, be compared to a camera obscura; the rays which flow from external objects, and enter the eye, painting an inverted picture of those objects on the retina: if you carefully dissect from the bottom of an eye, newly taken out of the head of an animal, a small portion of the tunica sclerotica and choroides, and place this eye in a hole made in the window shutter of a dark chamber, so that the bottom of the eye may be towards you; the pictures or images of external objects will be painted on the retina in lively colours, but inverted. In order to see how the several parts of the eye contribute to produce this effect, let us follow the rays proceeding from a luminous point, and see what will happen to them from the beforementioned properties of light. Since the rays of light flow from every visible point of a body in every direction, some of them, issuing from this point, will fall upon the cornea, and, entering a medium of greater density, will be refracted towards the perpendicular, and as they fall upon a convex spherical surface, nearly in a parallel state, the pupil being so extremely small, it is evident, from the principles of optics, that they will be made to converge: those which fall very obliquely will either be reflected, or falling upon the uvea, or pigmentum nigrum, which covers the ciliary ligaments, will be suffocated, and prevented from entering the internal parts of the eye: those which fall more directly, as was before said, become converging, in which state they fall upon the anterior surface of the crystalline humour, which, having a greater refracting power than the aqueous humour, and its surface being convex, will cause them to converge still more, in which state they will fall upon the posterior surface of the crystalline, or anterior surface of the vitreous humour; which having a less refractive power than the crystalline, they will be refracted from the perpendicular; but, as they fall upon a concave surface, it is evident, from the principles of optics, that they will be made to converge still more: in which state they will go on to the retina, and if the eye is well formed, the refraction of these several humours will be just sufficient to bring them to a point or focus on the retina. The same thing will happen to rays flowing from every other visible point of the object: the rays which flow from every point will be collected into a corresponding point on the retina, and, consequently, will paint the image of that object inverted; the rays coming from the superior part of any object, being collected on the inferior part of the retina, and vice versa, as is manifest from the principles of optics. If the rays are accurately, or very nearly, collected into a focus on the retina, distinct vision will be produced; but if they be made to converge to a point before or beyond the retina, the object will be seen indistinctly; this is proved by holding a convex or concave glass before the eye of a good sighted person: in the former case, the rays will be made to converge to a point before they arrive at the retina, and in the latter, to a point beyond it. In these cases, it is plain that the rays which flow from a point in the object, will not form a point, but a circular spot, upon the retina, and these various circles intermixing with other, will render the image very indistinct. This is well illustrated by the camera obscura, where if you hold the paper nearer or more remote than the focal distance of the lens, the picture will be indistinct. So far then, in the theory of vision, are we led by the principles of optics, and we can with certainty, by their assistance, affirm, that if the eye is sound, and the image of an object distinctly painted upon the retina, it will be seen distinctly, erect, and of its proper colours: so far we can proceed on safe and sure grounds, but if we venture further, we shall find ourselves bewildered in the regions of hypothesis and fancy. The machinery by which nature connects the material and immaterial world is hidden from our view; in most cases we must be satisfied with knowing that there are such connexions, and that these connexions invariably follow each other, without our being able to discover the chain that goes between them. It is to such connexions that we give the name of laws of nature; and when we say that one thing produces another by a law of nature, this signifies no more, than that one thing, which is called the cause, is constantly and invariably followed by another, which we call the effect, and that we know not how they are connected. But there seems a natural propensity in the mind of man, to endeavour to account for every phenomenon that falls under his view, which has given rise to a number of absurd and romantic conjectures in almost every branch of science. From this source has risen the vibration of the fibres of the optic nerve, or the undulation of a subtile ether, or animal spirits, by which attempts have been made to explain the theory of vision; but all of them are absurd and hypothetical. Kepler was the first who had any distinct notion of the formation of the pictures of objects on the bottom of the eye; this discovery he published about the year 1600. Joannes Baptista Porta had indeed got some rude notion of it prior to the time of Kepler, but as he knew nothing of the refraction made by the humours of the eye, his doctrine was lame and defective, for he imagines that the images are painted on the surface of the crystalline humour. The disputes concerning the theory of vision had very much divided the ancient philosophers; some of them imagining that vision was caused by the reception of rays into the eye; while a great many others thought it more agreeable to nature, that certain emanations, which they called visual rays, should flow from the eye to the object. We shall now inquire more particularly how each part of the eye is peculiarly fitted to produce distinct vision. Though the eye is composed of different humours, yet one might have been sufficient to collect the rays into a focus, and form the picture of an object upon the retina. By the experiments of the accurate Dr. Robertson, it appears that there is less difference in the density, as well as in the refracting power of the humours, than has been generally thought: by weighing them in a hydrostatic balance, he found that the specific gravities of the aqueous and vitreous humours were very nearly equal, each being nearly equal to that of water: and that the specific gravity of the crystalline did not exceed the specific gravity of the other humours in a greater proportion than that of about 11 to 10. Hence it would seem to follow, that the crystalline is not of such great use in bringing the rays together, and thereby forming the pictures of objects on the retina, as has been commonly thought by optical writers; for though in shape it resembles a double convex lens, and is, on that account, fitted to make the rays converge; yet, be cause it is situated between two humours nearly of the same refractive power with itself, it will alter the direction of the light but a little. From this, the reason is evident why the sight continues after the operation for the cataract, in which the crystalline is depressed, or extracted, and why a glass of small convexity is sufficient to supply the little refraction wanting, occasioned by the loss of this humour. But without doubt, several important purposes are effected by this construction of the eye; which could not have been attained if it had been composed of one humour only. Some of those purposes seem sufficiently evident to us; for instance, by placing the aqueous humor before the crystalline, and partly before the pupil, and making the cornea convex, a greater quantity of light is made to enter the eye than could otherwise have done without enlarging the size of the pupil; the light will also enter in a less diverging state than it could have done if the pupil had been enlarged, and consequently be more accurately collected to a focus on the retina; for a perfect eye can only collect such rays to a focus on that membrane, as pass through the pupil nearly in a state of parallelism. Another, and perhaps a principal advantage derived from the different humours in the eye, is, probably, to prevent that confusion arising from colour, which is the consequence of the different degrees of refrangibility of the rays of light. From the experiments of Mr. Dollond, it appears, though contrary to the opinion of Newton, and most other optical writers, that different kinds of matter differ extremely with respect to the divergency of colour produced by equal refractions; so that a lens may be contrived, composed of media of different dispersing powers, which will form the image of any object free of colour; this discovery Mr. Dollond has applied to the improvement of telescopes, with great success. It is by no means improbable, that nature has, for the same purpose, placed the crystalline lens betwen two media of different densities, and, probably, different dispersing powers, so that an achromatic image, free from the prismatic colours, will be formed on the retina. Indeed we find a conjecture of this kind, so long since as Dr. David Gregory's time, he says, in speaking of the imperfection of telescopes, "Quod si ob difficultates physicas, in speculis idoneis torno elaborandis, et poliendis, etiamnum lentibus uti oporteat, fortassis media diversae densitatis ad lentem objectivam componendam adhibere utile foret, ut a natura factum observamus in oculo, ubi crystallinus humor (fere ejusdem cum vitro virtutis ad radios lucis refringendos) aqueo et vitreo (aquae quoad refractionem hand absimilibus) conjungitur, ad imaginem quam distincte fieri poterit, a natura nihil frustra moliente, in oculi fundo depingendam." In describing the eye, I observed, that the crystalline humour was not every where of the same consistence, being much more hard and dense towards its centre, than externally: in the human eye, it is soft on the edges, and gradually increases in density as it approaches the centre: the reason of this construction is evident, at least we know of one use which it will serve; for, from the principles of optics, it is plain that the rays which fall at a distance from the axis of the crystalline, by reason of their greater obliquity, if the humour were of the same density in all its parts, would be more refracted than those which fall near its axis, so that they would meet at different distances behind the crystalline humour; those which pass towards its extremity, nearer, and those near its axis, at a greater distance, and could not be united at the same point on the retina, which would render vision indistinct; though the indistinctness arising from this cause, is only about the 1/5449 part of that which arises from the different refrangibility of the rays of light, as Sir Isaac Newton has demonstrated. Nature has, however, contrived a remedy for this also, by making the crystalline humour more dense and solid near its centre, that the rays of light which fall near its axis, may have their refraction increased, so as to meet at the same point with those which fall at a distance from its axis. _Of the manner in which the Eye conforms itself in order to see distinctly at different Distances._ It has been much disputed in what manner the eye conforms itself to see distinctly at different distances; for it is evident, that, without some change, the rays which flow from objects at different distances, could not be collected into a focus at the same point, and, consequently, though the eye might see distinctly at one distance, it could not at another. This subject has given rise to a variety of opinions, but few of them are satisfactory; and though several of them might explain the phenomena of vision, at different distances, yet it is by no means proved that those supposed changes do take place in the eye. I shall content myself with just mentioning the principal opinions on this subject, without engaging in a controversy, which has for a long time employed the ingenuity of philosophers to little purpose. Some are of opinion, that the whole globe of the eye changes its figure; becoming more oblong when objects are near, and more flat when they are removed to a greater distance; and this change in the figure of the eye is differently explained by different authors; some maintain that it is rendered oblong by the joint contraction of the two oblique muscles: others think that the four straight muscles acting together, compress the sides of the globe, and by this compression, reduce it to an oblong figure, when objects are near; and that, by its natural elasticity, it recovers its former figure when these muscles cease to act. Others again think that when these four straight muscles act together, they render the eye flat by pulling it inwards, and pressing the bottom of it against the fat; and that it is reduced to its former figure, either by the joint contraction of the two oblique muscles, or by the inherent elasticity of its parts, which exerts itself when the muscles cease to act. That, if such a change should take place in the eye, it would produce distinct vision, will be readily granted; but that such a one does not take place, at least in any of these ways, is, in my opinion, very certain. Dr. Porterfield thinks that the crystalline lens has a motion by means of the ligamentum ciliare, by which the distance between it and the retina is increased or diminished, according to the different distances of objects. The ligamentum ciliare, he says, is an organ, the structure and disposition of which excellently qualify it for changing the situation of the crystalline, and removing it to a greater distance from the retina, when objects are too near for us; for that, when it contracts, it will not only draw the crystalline forwards, but will also compress the vitreous humour, lying behind it, so that it must press upon the crystalline, and push it from the retina. Although this hypothesis will, in a great measure, account for distinct vision at different distances, yet it could only be of use where the rays enter the eye with a certain degree of divergency, while, however we are sure, that in looking at very distant objects which are at different distances from us, the eye undergoes a change. But a sufficient objection to Dr. Porterfield's hypothesis is, that it is by no means proved that the crystalline lens can be moved in the manner he supposes, or that the ligamentum ciliare is possessed of muscular fibres; on the contrary some eminent anatomists deny that they are. We shall now take a view of the opinion of M. de la Hire, who considered this subject, as well as almost every other relating to vision, with the closest attention; he maintains, that, in order to view objects distinctly at different distances, there is no alteration but in the size of the pupil, which is well known to contract and dilate itself according to the quantity of light flowing from the object we look at, being most contracted in the strongest light, and most dilated when the light is weakest; and consequently will contract when an object is held near the eye, and dilate as it is removed, because in the first case the quantity of light entering the eye is much greater than in the last. That this contraction of the pupil will have the effect of rendering vision distinct, especially when objects are within the furthest limits of distinct vision, will plainly appear, if we consider the cause of indistinct vision. Dr. Jurin has shown, that objects may be seen with sufficient distinctness, though the pencils of rays issuing from the points of them do not unite precisely in another point on the retina, but instead thereof, if they form a circle which does not exceed a certain magnitude, distinct vision will be produced; the circle formed by these rays on the retina he calls the circle of dissipation. The pupil will, by contracting, not only diminish the circles of dissipation, and thereby help to produce distinct vision, but will also prevent so great a quantity of light from falling near the circumferences of those circles; and Dr. Jurin has shown, that, if the light on the outer side of the circles of dissipation is diminished, the remainder will scarce affect the sense. In both these ways, the contraction of the pupil has a tendency to diminish the circles of dissipation, and, consequently, to produce distinct vision. This is likewise confirmed by experiment, for when an object is placed so near, that the pupil cannot be so much contracted as is necessary for distinct vision, the same end may be obtained by means of an artificial pupil: for, if a small hole is made in a card, a very near object may be viewed through it with the greatest ease and distinctness. Also, if a person have his back turned towards a window, and hold a book so near his eyes as not to be able to read, if he turn his face to the light, he will find, that he will be able to read it very distinctly; which is owing to the contraction of the pupil by means of the light. M. Le Roi, a member of the Royal Academy of Montpelier, has attempted to defend the opinion of M. de la Hire, and, indeed, it seems, of all others, the best supported by facts; but perhaps it may not account so well for vision at great distances. It is likewise rendered more probable by viewing the pictures of external objects, formed in a dark chamber, by rays coming through a hole in the window shutter; those pictures will be rendered distinct, by dilating, or contracting the aperture, without the assistance of a lens, accordingly as the object is more or less distant; those who have had the crystalline lens depressed, or extracted, by means of one glass can see objects pretty distinctly at different distances. These, and several other arguments that might be brought, tend to prove that the eye accommodates itself to view objects distinctly at different distances, chiefly by means of the motion of the pupil; and though this does not explain the phenomenon so satisfactorily as we could wish, yet it is certain, that it has a share in it; we are however certain, that, in whatever manner it may be produced, the eye has a power of accommodating itself to view objects distinctly enough at several different distances. _Concerning the Seat of Vision._ No subject has been more canvassed than that concerning what is improperly called the seat of vision. In early times, the crystalline lens was thought to be best qualified for this office; but this substance, though situated in the middle of the eye, which Baptista Porta thought to be the proper centre of observation, had universally given place to the better founded pretensions of the retina: and, from the time of Kepler, few ventured to dispute its claim to that office, till M. Mariotte was led, from some curious circumstances, to think that vision was not performed by the retina, but by the choroid coat. Having often observed in the dissections of men, as well as of brutes, that the optic nerve is not inserted exactly opposite to the pupil, that is, in the place where the picture of the objects upon which we look directly, is made: and that in man it is somewhat higher, and on the side towards the nose, he had the curiosity to examine the reason of this structure, by throwing the image of an object on this part of the eye. In order to do this, he fastened on a dark wall, about the height of his eyes, a small round paper, to serve for a fixed point of sight; and he fastened such another paper on the right hand, at the distance of about two feet, but rather lower than the former, so that light issuing from it, might strike the optic nerve of his right eye, while the left was kept shut. He then placed himself over against the former paper, and drew back by degrees, keeping his right eye fixed, and very steady upon it, and when he had retired about ten feet, he found that the second paper entirely disappeared. This, he says, could not be imputed to the oblique position of the second paper, with respect to his eye, because he could see more remote objects on the same side. This experiment he repeated by varying the distances of the paper and his eye. He also made it with his left eye, while the right eye was kept shut, the second paper being fastened on the left side of the point of sight; so that by the situation of the parts of the eye, it could not be doubted that this defect of vision is in the place where the optic nerve enters, where only the choroides isdeficient. From this he concludes, that the defect of vision is owing to the want of the choroid coat, and, consequently, that this coat is the proper organ of vision. A variety of other arguments in favour of the choroides occurred to him, particularly he observed that the retina is transparent, which he thought could only enable it to transmit the rays further, and he could not persuade himself that any substance could be considered as being the termination of the pencils, and the proper seat of vision, at which the rays are not stopped in their progress. Mr. Pequet, in answer to Mariotte's observation, says, that the retina is very imperfectly transparent, resembling oiled paper, or horn: and, besides, that its whiteness demonstrates that it is sufficiently opaque for stopping the rays of light as much as is necessary for vision: whereas, if vision be performed by means of those rays which are transmitted through such a substance as the retina, it must be very indistinct. Notwithstanding the plausibility of this opinion of M. Mariotte, and the number of celebrated men who joined him in it, I must confess, that none of their arguments, though very ingenious, have been able to make me a convert to that opinion. If we argue from the analogy of the other senses, in all of which the nerves form the proper seat of sensation, we shall be induced to give judgment in favour of the retina. And this argument from analogy is much strengthened, by considering that the retina is a large nervous apparatus, immediately exposed to the impressions of light; whereas the choroides receives but a slender supply of nerves, and seems no more fitted for the organ of vision than any other part of the body. But facts are not wanting which make still more in favour of the retina. It appears from observations made upon the sea calf and porcupine, that these animals have their optic nerves inserted in the axis of the eye, directly opposite the pupil, which renders it very improbable that the defect in sight, where the optic nerves enter, can be owing to the want of the choroides in that place; for were this true, then in those creatures which have the optic nerves inserted in the axis of the eye, and which by consequence do directly receive on the extremity of the nerve the pictures of objects, all objects would become invisible to which their eyes are turned, because the choroides is wanting in that place where the image falls; but this is contrary to experience. M. Le Cat, though he strenuously supports Mariotte's opinion, takes notice of a circumstance, which, if he had properly considered it, might have led him to a contrary conclusion: from a beautiful experiment he obtains data, which enable him with considerable accuracy to determine the size of the insensible spot in his eye, which he finds to be about 1/30 or 1/40 of an inch in diameter, and consequently only about 1/5 or 1/6 of the diameter of the optic nerve, that nerve being about 1/6 of an inch in diameter. I find that in my eye likewise, the diameter of the insensible spot is about 1/40 of an inch, or something less. Whence it is evident that vision exists where the choroid coat is not present, and consequently that the choroid coat is not the organ of vision. It is probably owing to the hardness and callosity of the retina where the nerve enters, that we have this defect of sight, as it has not yet acquired that softness and delicacy which is necessary for receiving such slight impressions as those of the rays of light, and this conjecture is rendered still more probable by an observation of M. Pequet, who tells us, that a bright and luminous object, such as a candle, does not absolutely disappear, but one may see its light, though faint. This not only shows that the defect of sight is not owing to a want of the choroides, but also that the retina is not altogether insensible where the nerve enters. These circumstances, in my opinion, render it certain, that the retina, and not the choroid coat, is the organ of vision. _Of our seeing Objects erect by inverted Images._ Another question concerning vision, which has very much perplexed philosophers, is this; how comes it that we see objects erect, when it is well known that their images or pictures on the retina are inverted? The sagacious Kepler, who first made this discovery, was the first that endeavoured to explain the cause of it. The reason he gives for our seeing objects erect, is this, that as the rays from different points of an object cross each other before they fall on the retina, we conclude that the impulse we feel upon the lower part of the retina comes from above; and that the impulse we feel from the higher part, comes from below. Des Cartes afterwards gave the same solution of this phenomenon, and illustrated it by the judgment we form of the position of objects which we feel with our arms crossed, or with two sticks that cross each other. But this solution is by no means satisfactory: first, because it supposes our seeing objects erect to be a deduction from reason, drawn from certain premises, whereas it seems to be an immediate perception; and secondly, because all the premises from which this conclusion is supposed to be drawn, are absolutely unknown to far the greater part of mankind, and yet they all see objects erect. Bishop Berkeley, who justly rejects this solution, gives another, founded on his own principles, in which he is followed by Dr. Smith. This ingenious writer thinks that the ideas of sight are altogether unlike those of touch; and since the notions we have of an object by these different senses, have no similitude, we can learn only by experience how one sense will be affected, by what, in a certain manner, affects the other. Thus, finding from experience, that an object in an erect position, affects the eye in one manner, and that the same object in an inverted position, affects it in another, we learn to judge, by the manner in which the eye is affected, whether the object is erect or inverted. But it is evident that Bishop Berkeley proceeds upon a capital mistake, in supposing that there is no resemblance between the extension, figure, and position, which we see, and that which we perceive by touch. It may be further observed, that Bishop Berkeley's system, with regard to material things, must have made him see this question, in a very different light from that in which it appears to those who do not adopt his system. In order to give a satisfactory answer to this question, we must first examine some of the laws of nature, which take place in vision; for by these the phenomena of vision must be regulated. It is now, I believe, pretty well established, as a law of nature, that we see every point of an object in the direction of a right line, which passes from the picture of that point on the retina, through the centre of the eye. This beautiful law is proved by a very copious induction of facts; the facts upon which it is founded are taken from some curious experiments of Scheiner, in his Fundamenta Optices. They are confirmed by Dr. Porterfield, and well illustrated by Dr. Reid. The seeing objects erect by inverted images is a necessary consequence of this law of nature: for from thence it is evident that the point of the object whose picture is lowest on the retina, must be seen in the highest direction from the eye; and that the picture which is on the right side of the retina, must be seen on the left. _Of seeing Objects single with two Eyes._ That we should have two pictures of an object, and yet see it single, has long been looked upon as a curious circumstance by philosophers: and of consequence, many attempts have been made to account for it, few of which, however, are satisfactory. As it would take up too much time to give a view of all the opinions on this subject, I shall pass over the opinions of Galen, Gassendus, Baptista Porta, Rohault, and others, which do not deserve a serious refutation; and shall content myself with making a few observations on the hypothesis of Bishop Berkeley. But it seems the most proper way of proceeding, first of all to consider the phenomena of single and double vision, in order, if possible, to discover some general principle to which they lead, and of which they are necessary consequences; and, for the sake of perspicuity, we shall premise the following definition. When a small object is seen single with both eyes, those points on the two retinas on which the pictures of the object fall, may be called corresponding points: and when the object is seen double, we shall call such points, non-corresponding points. Now we find that in sound and perfect eyes, when the axes of both are directed to one point, an object placed in that point is seen single; and in this case, the two pictures which show the object single, are painted on the centres of the retinas. Hence, the centres of the two retinas correspond. Other objects at the same distance from the eyes, as that to which their axes are directed, do also appear single: and in this case, it is evident to those who understand the principles of optics, that the pictures of an object to which the eyes are not directed, but which is at the same distance as that to which they are directed, fall both on the same side of the centre, that is, both to the right, or both to the left, and both at the same distance from the centre. Hence it is plain, that points in the retina, which are similarly situated with respect to the centres, are corresponding points. An object which is much nearer, or much more distant from the eyes, than that to which their axes are directed, appears double. In this case, it will easily appear, that the pictures of the object which is seen double, do not fall upon points which are similarly situated. From these facts, we are led to the following conclusion, viz. that the points of the two retinas, which are similarly situated with respect to the centres, correspond with each other, and that the points which are dissimilarly situated, do not correspond. The truth of this general conclusion is founded upon a a very full induction, which is all the evidence we can have for a fact of this nature. The next thing that seems to merit our attention, is, to inquire, whether this correspondence between certain points of the two retinas which is necessary to single vision, is the effect of custom, or an original property of the human eyes. We have a strong argument in favour of its being an original property, from the habit we get of directing our eyes accurately to an object; we get this habit by finding it necessary for perfect and distinct vision; because thereby, the two images of the object falling upon corresponding points, the eyes assist each other in vision, and the object is seen better by both eyes together, than by one: but when the eyes are not accurately directed, the two images of the object fall upon points which do not correspond, whereby the sight of the one eye disturbs that of the other. Hence it is not unreasonable to conclude, that this correspondence between certain points of the retina is prior to the habits we acquire in vision: and, consequently, natural and original. We have all acquired the habit of directing our eyes in one particular manner, which causes single vision; now if the Author of Nature had ordained that we should see objects single, only when our eyes are thus directed, there is an obvious reason why all mankind should agree in the habit of directing them in this manner; but, if single vision were the effect of custom, any other habit of directing the eyes would have answered the purpose; we therefore, on this supposition, can give no reason why this particular habit should be so universal. Bishop Berkeley maintains a contrary opinion, and thinks that our seeing objects single with both eyes, as well as our seeing them erect, by inverted images, depends upon custom. In this he is followed by Dr. Smith, who observes, that the question, why we see objects single with both eyes, is of the same nature with this, why we hear sounds single with both ears; and that the same answer will serve for both; whence he concludes, that as the second of these phenomena is the effect of custom, so also is the first. But I think, that the questions are not so much of the same sort, as that the same answer will serve for both; and, moreover, that our hearing single with both ears is not the effect of custom. No person will doubt that things which are produced by custom, may be undone by disuse, or by a contrary custom. On the other hand, it is a strong argument, that an effect is not owing to custom, but to the constitution of nature, when a contrary custom, long continued, is found neither to change nor weaken it. Now it appears, that from the time we are able to observe the phenomena of single and double vision, custom makes no change in them, every thing which at first appeared double, appearing so still in the same circumstances. Dr. Smith has adduced some facts in favour of his opinion, which, though curious, seem by no means decisive. But in the famous case of the young man couched by Mr. Cheselden, after having had cataracts in both his eyes till his thirteenth year, it appears that he saw objects single from the time he began to see with both eyes. And the three young gentlemen mentioned by Dr. Reid, who had squinted, as far as he could learn, from infancy, as soon as they learned to direct both eyes to an object, saw it single. In these cases it is evident that the centres of the retina corresponded originally, for Mr. Cheselden's young man had never seen at all before he was couched, and the other three had never been accustomed to direct the axes of both eyes to the same point. These facts render it probable, that this correspondence is not the effect of custom, but of fixed and immutable laws of nature. With regard to the cause of this correspondence, many theories have been proposed, but as none of them can be looked on in any other light than as probable conjectures, I think it would be to little purpose to notice them. That of the illustrious Newton is the most ingenious of any, and though it has more the appearance of truth than any other, that great man has proposed it under the modest form of a query. Having given a short account of the principal phenomena of vision, I proceed next to treat of some of the diseases to which this sense is subject, I shall first take notice of the deformity called squinting. _Of Squinting._ Though this is a subject which well deserves our particular attention, yet having spoken of such a variety of subjects in the preceding part of this lecture, I have not time for many observations on this. I shall just mention the principal opinions, concerning the cause of this deformity, and point out that which seems to me most probable. This subject is certainly very worthy the attention of the physician, as it is a case concerning which he may often be consulted, and which it may be sometimes in his power to cure. A person is said to squint, when the axes of both his eyes are not directed to the same object. This defect consists in the wrong direction of one of the eyes only. I have never met with an instance in which both eyes had a wrong direction, neither have I seen one accurately described by any author. The generality of writers on this subject have supposed this defect to proceed from a disease of, or want of proper correspondence in, the muscles of the eyes, which not acting in proper concert with one another, as in persons free from this blemish, are not able to point both eyes to the same object. But this, I think, is very seldom the cause, for when the other eye is shut, the distorted eye can be moved by the action of its muscles, in all possible directions, as freely as that of any other person, which shows that it is not owing to a defect in the muscles, neither is it owing to a want of correspondence in the muscles of both eyes; for when both eyes are open, and the undistorted eye is moved in any direction whatever, the other always accompanies it, and is turned the same way at the same instant of time. I shall next take notice of the hypothesis of M. de la Hire, who supposes, that in the generality of mankind, that part of the retina which is seated in and about the axis of the eye, is of a more delicate sense and perception than what the rest of the coat is endowed with; and therefore we direct both axes to the same object, chiefly in order to receive the picture on that part of the retina which can best perceive it; but in persons who squint, he conceives the most sensible part of the retina of one eye, not to be placed in the axis, but at some distance from it: and that, therefore, this more sensible part of the retina is turned towards the object, to which the other eye is directed, and thus causes squinting. This ingenious hypothesis has been followed by Dr. Boerhaave, and many other eminent physicians. If it be true, then if the sound eye be shut, and the distorted eye alone be used to look at an object, it must still be as much distorted as before, for the same reason: but the contrary is true in fact; for if you desire such a person to close his other eye and look at you with that which is usually distorted, he will immediately turn the axis of it directly towards you. If you bid him open the undistorted eye, and look at you with both eyes, you will find the axis of this last pointed at you and the other turned away, and drawn close to the nose, or perhaps to the upper eye lid. From these facts, and some others mentioned by Dr. Jurin, I think we may conclude that this defect is seldom, if ever, occasioned by such a preternatural make of the eye, as M. de la Hire supposed. From the most accurate observations it will appear, that by far the most common cause of squinting, is a defect in the distorted eye. Dr. Reid examined above twenty people that squinted, and found in all of them a defect in the sight of one eye; M. Buffon likewise, from a great number of observations, has found that the true and original cause of this blemish, is an inequality in the goodness, or in the limits of distinct vision, in the two eyes. Dr. Porterfield says this is generally the case with people who squint; and I have found it so in all that I have had an opportunity of examining. With regard to the nature of this defect, the distorted eye is sometimes more convex, and sometimes more flat, than the sound one; sometimes it does not depend upon the convexity, but upon a weakness, or some other affection, of the retina, of the nature of which we are ignorant. It will be easy to conceive how this inequality of goodness in the two eyes, when in a certain degree, must necessarily occasion squinting, and that this blemish is not a bad habit, but a necessary one, which the person is obliged to learn, in order to see with advantage. When the eyes are equally good, an object will appear more distinct and clear when viewed with both eyes than with only one; but the difference is very little. The ingenious Dr. Jurin, who has made some beautiful experiments to ascertain this point, has shown, that when the eyes are equal in goodness, we see more distinctly with both than with one, by about one thirteenth part only. But M. Buffon has found that when the eyes are unequal, the case will be quite different. A small degree of inequality will make the object, when seen with the better eye alone, appear equally bright or clear, as when seen with both eyes; a little greater inequality will make the object appear less distinct when seen with both eyes, than when it is seen with the stronger eye alone; and a still greater inequality will render the object, when seen with both eyes, so confused, that in order to see it distinctly, one will be obliged to turn aside the weak eye, and put it into a situation where it cannot disturb the sight of the other. The truth of this may be easily proved by experiment. Let a person take a convex lens, and hold it about half an inch before one of his eyes; he will, by these means, render them very unequal. and if he attempt to read with both eyes, he will perceive a confusion in the letters, caused by this inequality; which confusion will disappear as soon as he shuts the eye which is covered with the lens, and looks only with the other. Squinting is a necessary consequence of this inequality in the goodness of the two eyes; for a person whose eyes are to a certain degree unequal, finds that, when he looks at an object, he sees it very indistinctly; every conformation, or change of direction of his eyes which lessens the evil, will be agreeable; and he will acquire a habit of turning his eye towards the nose, not for the sake of seeing better with it, but in order to avoid, as much as possible, seeing at all with the distorted eye; for which purpose it will be drawn either under the upper eye lid, so that the pupil may be entirely or partially covered; or directly towards the nose, in which case the image of the object will fall at a distance from the axis of the eye: and it is a fact well known to philosophers, that we never naturally attend to an image which is at a distance from the axis; so that in this situation it will give little disturbance to the sight of the other. It is easy to show that a squinting person very seldom, if ever, sees an object with the distorted eye. Indeed in above forty cases that I have examined, I found that when I placed an opaque body between the undistorted eye and the object, it immediately disappeared, nor were they able to see it at all, till they directed the axis of the distorted eye to the object. I find the same observation made by Dr. Reid and M. Buffon. M. Buffon takes notice of a fact which I have often observed; viz. that many persons have their eyes very unequal without squinting. When the difference is very considerable, the weak eye does not turn aside, because it can see almost nothing, and therefore cannot disturb the vision of the good eye. Also, when the inequality is but small, the weak eye will not turn aside, as it affords very little disturbance to the sight of the other: when the inequality consists in the difference of convexity, or difference of the limits of distinct vision, having the limits of distinct vision in each eye given, it may be calculated with some degree of accuracy what degree of inequality is necessary to produce squinting. It seems then that there are certain limits with regard to the inequality of the eyes, necessary to produce this deformity; and that if the inequality be either greater or less than these limits, the person will not squint. Having now endeavoured to show what is the most common cause of squinting, I shall briefly attempt to point out those cases in which we may expect to effect a cure, and afterwards give a very short account of the most likely methods of doing it. We cannot have great hopes of success, when there is a very great defect in the distorted eye. When the eyes are of different convexities, there is no other way of removing the deformity, than by bringing them to an equality by means of glasses, and then the person would only look straight when he used spectacles. When this defect is owing to a weakness in the distorted eye, it may sometimes be cured: M. Buffon observes that a weak eye acquires strength by exercise, and that many persons, whose squinting he had thought to be incurable, on account of the inequality of their eyes, having covered their good eye for a few minutes only, and consequently being obliged to exercise their bad one for that short time, were themselves surprised at the strength it had acquired, and on measuring their view afterwards, he found it to be more extended, and judged the squinting to be curable. In order therefore to judge with any certainty of the possibility of a cure, it ought always to be tried whether the distorted eye will grow better by exercise; if it does not, we can have little hopes of success; but when the eyes do not differ much in goodness, and it is found that the distorted eye acquires strength by exercise, a cure may then be attempted: and the best way of doing it, (according to M. Buffon) is to cover the good eye for some time, for, in this condition, the distorted eye will be obliged to act, and turn itself towards objects, which by degrees will become natural to it. When the eyes are nearly brought to an equality by exercise, but cannot both be directed to the same point, Dr. Jurin's method may be practised, which is as follows. If the person is of such an age, as to be capable of observing directions, place him directly before you, and let him close the undistorted eye, and look at you with the other; when you find the axis of this fixed directly upon you, bid him endeavour to keep it in that situation, and open the other eye; you will now see the distorted eye turn away from you towards his nose, and the axis of the other will be pointed towards you, but with patience and repeated trials he will, by degrees, be able to keep the distorted eye fixed upon you, at least for some time after the other is opened, and when you have brought him to keep the axis of both eyes fixed upon you, as you stand directly before him, it will be time to change his posture, and set him, first a little to one side of you, and then to the other, and so practise the same thing. And when, in all these situations, he can perfectly and readily turn the axes of both eyes towards you, the cure is effected. An adult person may practice all this before a mirror, without a director, though not so easily as with one: but the older he is, the more patience will be necessary. With regard to the success of this method, M. Buffon says, that having communicated his scheme to several persons, and, among others, to M. Bernard de Jussieu, he had the satisfaction to find his opinion confirmed by an experiment of that gentleman, which is related by Mr. Allen, in his Synopsis Universae Medicinae. Dr. Jurin tells us that he had attempted a cure in this manner with flattering hopes of success, but was interrupted by the young gentleman's falling ill of the small pox, of which he died. Dr. Reid likewise tried it with success on three young gentlemen, and had brought them to look straight when they were upon their guard. Upon the whole this seems by much the most rational method of attempting to cure the deformity. The only remaining morbid affections of the eye which I shall take notice of in this lecture, are two, which produce the indistinct vision of an object, by directly opposite means. The first is caused by the cornea, and crystalline, or either of them, being too convex, or the distance between the retina and crystalline being too great. It is evident, that from any of these causes, or all combined, the distinct picture of an object, at an ordinary distance, will fall before the retina, and therefore the picture on the retina itself must be confused, which will render the vision confused and indistinct; whence, in order to see things distinctly, people whose eyes are so formed are obliged to bring the object very near their eyes; by which means the rays fall upon the eye in a more diverging state, so that a distinct picture will be formed on the retina, by which the object will be distinctly seen: from the circumstance of such persons being obliged to hold objects near their eyes, in order to see them distinctly, they are called short sighted. If a short sighted person look at an object through a small hole made in a card, he will be able to see even remote objects, with tolerable distinctness, for this lessens the circles of dissipation on the retina, and thus lessens the confusion in the picture. For the same purpose, we commonly observe short sighted people, when they wish to see distant objects more distinctly, almost shut their eye lids: and it is from this, says Dr. Porterfield, that short sighted persons were anciently called myopes. The sight of myopes is remedied by a concave lens of proper concavity, which, by increasing the divergency of the rays, causes them to be united into a focus on the retina: and they do not require different glasses for different distances, for, if they have a lens which will make them see distinctly at the distance most commonly used by other persons, for example, at the distance at which persons whose eyes are good generally read, they will, by the help of the same glass, be able to see distinctly at all the distances at which good sighted people can see distinctly: for the cause of shortsightedness, is not a want of power to vary the conformation of the eye, but is owing to the whole quantity of refraction being too great for the distance of the retina from the cornea. The other defect to be mentioned, is of an opposite nature, and persons labouring under it are called long sighted, or presbytae: it is caused by the cornea and crystalline, or either of them, being too flat in proportion to the distance between the crystalline and retina: whence it follows, that the rays which come from an object at an ordinary distance, will not be sufficiently refracted, and, consequently, will not meet at the retina, but beyond it, which will render the picture on the retina confused, and vision indistinct. Whence, in order to read, such persons are obliged to remove the book to a great distance, which lessens the divergency of the rays falling on the eye, and makes them converge to a focus sooner, so as to paint a distinct image on the retina. The presbytical eye is remedied by a convex lens of proper convexity, which makes the rays converge to a focus sooner, and thus causes distinct vision: the sight of such persons is even more benefited by a convex lens, than that of myopes by a concave one; for a convex lens not only makes the picture of the object on the retina distinct, but also more bright, by causing a greater quantity of light to enter the pupil; while a concave one, at the same time that it renders vision distinct, diminishes the quantity of light. Long sighted persons commonly become more so as they advance in years, owing to a waste of the humours of the eye; and even many people whose sight was very good in their youth, cannot see without spectacles when they grow old. The same waste in the humours of the eye, is the reason why shortsighted persons commonly become less so as they advance in years; so that many who were shortsighted in their youth, come to see very distinctly when they grow old. Dr. Smith seems to doubt this, and thinks that it is rather a hypothesis than a matter of fact. I have however myself seen several instances in confirmation of it; and it is very natural to suppose, that since short and long sight depend upon directly opposite causes, and since the latter is increased by age, the former must be diminished by it. LECTURE IX. THE LAWS OF ANIMAL LIFE. In the preceding lectures I have taken a view, first of the general structure and functions of the living body, and next of the different organs called senses, by means of which we become acquainted with external objects. I shall next endeavor to show that, through the medium of these different senses, external objects affect us in a still different manner, and by their different action, keep us alive: for the human body is not an automaton; its life, and its different actions, depend continually on impressions made upon it by external objects. When the action of these ceases, either from their being withdrawn, or from the organization necessary to perceive them, being deranged or injured, the body becomes a piece of dead matter; becomes obedient to the common laws of chemical attraction, and is decomposed into its pristine elements, which, uniting with caloric, form gases; which gases, being carried about in the atmosphere, or dissolved in water, are absorbed by plants, and contribute to their nourishment. These are devoured by animals, which in their turn die, and are decompounded; thus, in the living world, as well as in the inanimate, every thing is subject to change, and to be renewed perpetually. "Look nature through, 'tis revolution all, All change, no death; day follows night; and night, The dying day; stars rise, and set, and rise; Earth takes th' example; see the summer gay, With her green chaplet, and ambrosial flowers, Droops into pallid autumn; winter gray, Horrid with frost, and turbulent with storm, Blows autumn and his golden fruits away, Then melts into the spring; soft spring with breath Favonian, from warm chambers of the south Recals the first. All to reflourish, fades; As in a wheel, all sinks to reascend." The subject on which we are entering is of the utmost importance; for, by pointing out the manner in which life is supported and modified by the action of external powers, it discovers to us the true and only means of promoting health and longevity; for the action of these powers is generally within our own direction; and if the action of heat, food, air, and exercise, were properly regulated, we should have little to fear from the attacks of diseases. When we examine the human body, the most curious and unaccountable circumstance that we observe, is its life, or its power of motion, sensation, and thought: for though the structure of the different parts which we have examined must excite our admiration and wonder, each part being admirably fitted for the performance of its different functions, yet without the breath of life, all these beautiful contrivances would have been useless. We have seen that the structure of the eye indicates in its contriver, the most consummate skill in optics; and of the ear the most perfect knowledge of sounds; yet if sensibility had not being given to the nerves which administer to these organs, the pulses of the air might have been communicated to the fluid in the labyrinth, and the rays of light might have formed images in the retina, without our being, in the smallest degree, conscious of their existence. Though our efforts to discover the nature of life have hitherto been, and perhaps always will be, unsuccessful, yet we can, by a careful induction, or observation of facts, discover the laws by which it is governed, with respect to the action of external objects. This is what I shall now attempt to do. The first observation which strikes us, is that of the very different effects that are produced when inanimate bodies act on each other, and when they exert their action on living matter. When dead matter acts upon dead or inanimate matter, the only effects we perceive are mechanical, or chemical; that is, either motion, or the decomposition and new combination of their parts. If one ball strikes another, it communicates to it a certain quantity of motion, this is called mechanical action; and if a quantity of salt, or sugar, be put into water, the particles of salt, or sugar, will separate from each other, and join themselves to the particles of the water; these substances in these instances are said to act chemically on each other, and in all cases whatever, in which inanimate or dead bodies act on each other, the effects produced are motion, or chemical attraction; for though there may appear to be other species of action which sometimes take place, such as electric and magnetic attraction and repulsion, yet these are usually referred to the head of mechanical action or attraction. But when dead matter acts upon those bodies we call living, the effects produced are much different. There are many animals which pass the winter in a torpid state which has all the appearance of death; and they would continue in that state, if deprived of the influence of heat; now heat if applied to dead matter, will only produce motion, or chemical combination: in fluids it produces motions by occasioning a change in their specific gravity; and we know that it is one of the most powerful agents in chemical combination and decomposition; but these are the only effects it produces when it acts upon dead matter. But let us examine its effects when applied to living organized bodies. Bring a snake or other torpid animal into a moderately warm room, and observe what will be the consequence. After a short time the animal begins to move, to open its eyes and mouth; and when it has been subject to the action of heat for a longer time, it crawls about in search of food, and performs all the functions of life. Here then, dead matter, when applied to the living body, produces the living functions, sense and motion: for if the heat had not been applied, the animal would have continued senseless, and apparently lifeless. In more perfect animals, the effects produced by the action of dead matter upon them, are more numerous, and are different in different living systems; but are in general the following; sense and motion in almost all animals, and in many the power of thinking, and other affections of the mind. The powers, or dead matters, which by their action produce these functions, are chiefly heat, food, and air. The proof that these powers do produce the living functions is in my opinion very satisfactory, for when their action is suspended, the living functions cease. If we take away, for instance, heat, air, and food, from animals, they soon become dead matter. This is as strong a proof that these matters are the cause of the functions, as that heat is the cause of the expansion of bodies, when we find that by withdrawing it the expansion ceases. Indeed it is not necessary that an animal should be deprived of all these powers to put a stop to the living functions; if any one of them is taken away, the body sooner or later becomes dead matter: it is found by experience, that if a man is deprived of air, he dies in about three or four minutes; for instance, if he is immersed under water: if he is deprived of heat, or in other words is exposed to a very severe degree of cold, he likewise soon dies; or if he is deprived of food, his death is equally certain, though more slow; it is sufficiently evident then that the living functions are owing to the action of these external powers upon the body. What I have here said is not confined to animals, but the living functions of vegetables are likewise caused by the action of dead matter upon them. The powers, which by their actions produce the living functions of vegetables, are principally heat, moisture, light, and air. From what has been said, it clearly follows, that living bodies must have some property different from dead matter, which renders them capable of being acted on by these external powers, so as to produce the living functions; for if they had not, it is evident that the only effects which these powers could produce, would be mechanical, or chemical. Though we know not exactly in what this property consists, or in what manner it is acted on, yet we see that when bodies are possessed of it, they become capable of being acted on by external powers, so as to produce the living functions. We may call this property, with Haller, irritability, or, with Brown, excitability; or we may use vital principle, or any other term, could we find one more appropriate. I shall use the term excitability, as perhaps the least liable to exception, and in using this term, it is necessary to mention that I mean only to express a fact, without the smallest intention of pointing out the nature of that property which distinguishes living from dead matter; and in this we have the illustrious example of Newton, who called that property which causes bodies in certain situations to approach each other, gravitation, without in the least hinting at its nature. Yet though he knew not what gravitation was, he investigated the laws by which bodies were acted on by it, and thus solved a number of phenomena which were before inexplicable: in the same manner, though we are ignorant of the nature of excitability, or of the property which distinguishes living from dead matter, we can investigate the laws by which dead matter acts upon living bodies through this medium. We know not what magnetic attraction is, yet we can investigate its laws: the same may be observed with respect to electricity. If ever we should obtain a knowledge of the nature of this property, it would make no alteration in the laws which we had before discovered. Before we proceed to the investigation of the laws by which the living principle or excitability is acted on, it will be first necessary to define some terms, which I shall have occasion to use, to avoid circumlocution: and here it may not be improper to observe, that most of our errors in reasoning have arisen from want of strict attention to this circumstance, the accurate definition of those terms which we use in our reasoning. We may use what terms we please, provided we accurately define them, and adhere strictly to the definition. On this depends the excellence and certainty of the mathematical sciences. The terms are few, and accurately defined; and in their different chains of reasoning mathematicians adhere with the most scrupulous strictness to the original definition of the terms. If the same method were made use of in reasoning on other subjects, they would approach to the mathematics in simplicity and in truth, and the science of medicine in particular would be stripped of the heaps of learned rubbish which now encumber it, and would appear in true and native simplicity. Such is the method I propose to follow: I am certain of the rectitude of the plan; of the success of the reasoning it does not become me to judge. When the excitability is in such a state as to be very susceptible of the action of external powers, I shall call it abundant or accumulated; but when it is found in a state not very capable of receiving their action, I say it is deficient or exhausted. Let no one however suppose that by these terms I mean to hint in the least at the nature of the excitability. I do not mean by them that it is really at one time increased in quantity or magnitude, and at another time diminished: its abstract nature is by no means attempted to be investigated. These or similar terms the poverty or imperfection of language obliges us to use. We know nothing of the nature of the excitability or vital principle, and by the terms here used I mean only to say, that the excitability is sometimes easily acted on by the external powers, and then I call it abundant or accumulated; at other times the living body is with more difficulty excited, and then I say the vital principle or excitability, whatever it may be, is deficient or exhausted. On examination we shall find the laws by which external powers act on living bodies to be the following. First, when the powerful action of the exciting powers ceases for some time, the excitability accumulates, or becomes more capable of receiving their action, and is more powerfully affected by them. If we examine separately the different exciting powers which act on the body, we shall find abundant confirmation of this law. Besides the exciting powers which act on the body, which I mentioned; viz. heat, food, and air, there are several others, such as light, sound, odorous substances, &c. which will be examined in their proper places. These powers, acting by a certain impulse, and producing a vigorous action of the body, are called stimulants, and life we shall find to be the effect of these and other stimulants acting on the excitability. The stimulus of light, though its influence in this respect is feeble, when compared with some other external powers, yet has its proportion of force. This stimulus acts upon the body through the medium of the organ of vision. Its influence on the animal spirits strongly demonstrates its connexion with animal life, and hence we find a cheerful and depressed state of mind in many people, and more especially in invalids, to be intimately connected with the presence or absence of the sun. Indeed to be convinced of the effects of light we have only to examine its influence on vegetables. Some of them lose their colour when deprived of it, many of them discover a partiality to it in the direction of their flowers; and all of them perspire oxygen gas only when exposed to it; nay it would seem that organization, sensation, spontaneous motion, and life, exist only at the surface of the earth, and in places exposed to light. Without light nature is lifeless, inanimate, and torpid. Let us now examine if the action of light upon the body is subject to the law that has been mentioned. If a person be kept in darkness for some time, and then be brought into a room in which there is only an ordinary degree of light, it will be almost too oppressive for him, and will appear excessively bright; and if he have been kept for a considerable time in a very dark place, the sensation will be very painful. In this case, while the retina or optic nerve was deprived of light, its excitability accumulated, or became more easily affected by light: for if a person go out of one room into another, which has an equal degree of light, he will perceive no effect. You may convince yourselves of the truth of this law, by a very simple experiment; shut your eyes, and cover them for a minute or two with your hand, and endeavour not to think of the light, or what you are doing; then open them, and the daylight will for a short time appear brighter. If you look attentively at a window for about two minutes, then cast your eyes upon a sheet of white paper, the shape of the window frames will be perfectly visible upon the paper; those parts which express the wood work appearing brighter than the other parts. The parts of the optic nerve on which the image of the frame falls, are covered by the wood work from the action of the light; the excitability of these parts will therefore accumulate; and the parts of the paper which fall upon them must of course appear brighter. If a person be brought out of a dark room where he has been confined, into a field covered with snow, when the sun shines, it has been known to affect him so much as to deprive him of sight altogether. This law is well exemplified when we come into a dark room in the day time. At first we can see nothing; but with the absence of light the excitability accumulates, and we begin to have an imperfect glimpse of the objects around us; after a while the excitability of the retina is so far accumulated, and we become so sensible of the feeble light reflected from the surfaces of bodies, that we can discern their shapes, and sometimes even their colours. Let us next consider what happens with respect to heat, which is a uniform and active stimulus in promoting life. The extensive influence of heat upon animal life is evident from its decay and suspension during winter, in certain animals, and from its revival upon the approach and action of the vernal sun. If this stimulus is for some time abstracted from the whole body, or from any part, the excitability accumulates, or, in other words, if the body has been for some time exposed to cold, it is more liable to be affected by heat afterwards applied. Of this also you may be convinced by an easy experiment. Put one of your hands into cold water, and then put both into water which is considerably warm: the hand which has been in the cold water will feel much warmer than the other. If you handle some snow in one hand while you keep the other in the bosom, that it may be of the same heat with the body, and then bring both within the same distance of the fire, the heat will affect the cold hand infinitely more than the warm one. This is a circumstance of the utmost importance, and ought always to be carefully attended to. When a person has been exposed to a severe degree of cold for some time, he ought to be cautious how he comes near a fire, for his excitability will be so much accumulated that the heat will act very violently, often producing a great degree of inflammation, and even sometimes of mortification. This is a very common cause of chilblains, and other similar inflammations. When the hands, or any other parts of the body, have been exposed to a violent cold, they ought first to be put in cold water, or even rubbed with snow, and exposed to warmth in the gentlest manner possible. The same law regulates the action of food, or matters taken into the stomach: if a person have for some time been deprived of food, or have taken it in small quantity, whether it be meat or drink, or if he have taken it of a less stimulating quality, he will find that when he returns to his ordinary mode of life it will have more effect upon him than before he lived abstemiously. Persons who have been shut up in a coal work, from the falling in of the pit, and have had nothing to eat for two or three days, have been as much intoxicated by a bason of broth, as a person in common circumstances with two or three bottles of wine. This circumstance was particularly evident among the poor sailors who were in the boat with Captain Bligh after the mutiny. The Captain was sent by government to convey some plants of the bread fruit tree from Otaheite to the West Indies: soon after he left Otaheite the crew mutinied, and put the captain and most of the officers, with some of the men, on board the ship's boat, with a very short allowance of provisions, and particularly of liquors, for they had only six quarts of rum, and six bottles of wine, for nineteen people, who were driven by storms about the south sea, exposed to wet and cold all the time, for nearly a month; each man was allowed only a teaspoonful of rum a day, but this teaspoonful refreshed the poor men, benumbed as they were with cold, and faint with hunger, more than twenty times the quantity would have done those who were warm and well fed; and had it not been for the spirit having such power to act upon men in their condition, they never could have outlived the hardships they experienced. All these facts, and many others which might be brought forward, establish, beyond dispute, the truth of the law I mentioned; viz. that when the powerful action of the exciting powers ceases for some time, the excitability accumulates, or becomes more capable of receiving their actions, and is more powerfully affected by them. When the legs or arms have for some time been exposed to cold, the slightest exertion, or even the stimulus of a gentle heat, throws the muscles into an inordinate action or cramp. The glow of the skin, in coming out of a cold bath, may be explained on the same principle. The heat of the skin is diminished by the conducting power of the water, in consequence of which the excitability of the cutaneous vessels accumulates; and the same degree of heat afterwards applied, excites these now more irritable vessels to a great degree of action. On this principle depends the supposed stimulant or tonic powers of cold, the nature of whose action has been much mistaken by physicians and physiologists. Heat is allowed to be a very powerful stimulus; but cold is only a diminution of heat; how then can cold act as a stimulus? In my opinion it never does; but its effects may be explained by the general law which we have been investigating. When a lesser stimulus than usual has been applied to the body, the excitability accumulates, and is then affected by a stimulus even less than that which, before this accumulation, produced no effect whatever. The cold only renders the body more subject to the action of heat afterwards applied, by allowing the excitability to be accumulated. No person, I believe, ever brought on an inflammation, or inflammatory complaint, by exposure to cold, however long might have been that exposure, or however great the cold; but if a person have been out in the cold air, and afterwards come into a warm room, an inflammatory complaint will most probably be the consequence. Indeed coming out of the cold air into a moderately warm room generally produces a lively and continued warmth in the parts that have been exposed. The second general law is, that when the exciting powers have acted with violence for a considerable time, the excitability becomes exhausted, or less fit to be acted on; and this we shall be able to prove by a similar induction. Let us first examine the effects of light upon the eye: when it has acted violently for some time on the optic nerve, it diminishes the excitability of that nerve, and renders it incapable of being affected by a quantity of light, that would at other times affect it. When we have been walking out in the snow, if we come into a room, we shall scarcely be able to see any thing for some minutes. If you look stedfastly at a candle for a minute or two, you will with difficulty discern the letters of a book which you were before reading distinctly. When our eyes have been exposed to the dazzling blaze of phosphorus in oxygen gas, we can scarcely see any thing for some time afterwards, and if we look at the sun, the excitability of the optic nerve is so overpowered by the strong stimulus of his light, that nothing can be seen distinctly for a considerable time. If we look at the setting sun, or any other luminous object of a small size, so as not greatly to fatigue the eye, this part of the retina becomes less sensible to smaller quantities of light; hence when the eyes are turned on other less luminous parts of the sky, a dark spot is seen resembling the shape of the sun, or other luminous object on which our eyes have been fixed. On this account it is that we are some time before we can distinguish objects in an obscure room, after coming from broad daylight, as I observed before. We shall next consider the action of heat. Suppose water to be heated to 90 degrees, if one hand be put into it, it will appear warm; but if the other hand be immersed in water heated to 120 degrees, and then put into the water heated to 90 degrees, that water will appear cold, though it will still feel warm to the other hand: for the excitability of the hand has been exhausted, by the greater stimulus of heat, to such a degree as to be insensible of a less stimulus. Before we go into a warm bath, the temperature of the air may seem very warm and pleasant to the body, even though exposed naked to it; but after we have remained for some time in the warm bath, we feel the air, when we come out, very cool and chilling, though it is of the same temperature as before; for the hot water exhausts the excitability of the vessels of the skin, and renders them less capable of being affected by a smaller degree of heat. Thus we see that the effects of the hot and cold bath are different and opposite; the one debilitates by stimulating, and the other produces stimulant or tonic effects by debilitating. This seeming paradox may, however, be easily explained by the principles we have laid down; and though the hot and cold bath produce such different effects, yet it is only the same fluid, with a small variation in the degree of temperature; but these effects depend on the temperature of our body being such, that a small decrease of it will produce an accumulation of excitability, while a small increase will exhaust it. I shall next proceed to examine the effects of the substances taken into the stomach; and as the effects of spirituous and vinous liquors are a little more remarkable than those of food, I shall first begin with them. A person who is not accustomed to take these liquors, will be intoxicated by a quantity that will produce no effect upon one who has been some time accustomed to take them; and when a person has used himself to these stimulants for some time, the ordinary powers which in common support life, will not have their proper effects upon him, because his excitability has been, in some measure, exhausted by these stimulants. The same holds good with respect to tobacco and opium; a person accustomed to take opium, or smoke tobacco, will not be affected by a quantity that would completely intoxicate one not used to them, because the excitability has been so far exhausted by the use of those stimulants, that it cannot be acted on by a smaller quantity. That tobacco or opium act in the same manner as wine or spirits, scarce needs any illustration. In Turkey they intoxicate themselves with opium, in the same way that people in this country do with wine and spirits; and those who have been accustomed to take this drug for a considerable time, feel languid and depressed when they are deprived of it for some time; they repair to the opium houses, as our dram drinkers do to the gin shops in the morning, sullen, dejected, and silent; in an hour or two, however, they are all hilarity. This shows the effects of opium to be stimulant. Tobacco intoxicates those who are not accustomed to it, and in those who are, it produces a serene and composed state of mind by its stimulating effects. Like opium and fermented liquors it exhausts the excitability, and leaves the person dejected, and all his senses blunted, when its stimulant effects are over. That what is more properly called food acts in the same way as the substances I have just examined, is evident from the fact which I mentioned some time ago, that persons whose excitability has been accumulated, by their being deprived of food for some days, have been intoxicated by a bason of broth. These facts, with innumerable others which will easily suggest themselves, prove, beyond doubt, the truth of the second law, namely, that when the exciting powers have acted violently, or for a considerable time, the excitability is exhausted, or less fit to be acted on. Besides the stimulants which I have mentioned, there are several others which act upon the body, many of which will hereafter be considered: but all act according to this law; when their action has been suspended or diminished, the excitability of the organ on which they act becomes accumulated, or more easily affected by their subsequent action; and, on the contrary, when their action has been violent, or long continued, the excitability becomes exhausted, or less fit to receive their actions. Among the stimulants acting on the body, we may mention sound, which has an extensive influence on human life. I need not mention here its numerous natural, or artificial sources, as that has been fully done in a preceding lecture. The effect of music, in stimulating and producing a state of mind approaching to intoxication, is universally known. Indeed the influence of certain sounds in stimulating, and thereby increasing, the powers of life, cannot be denied. Fear produces debility, which has a tendency to death. Sound obviates this debility, and restores to the system its natural degree of excitement. The schoolboy and the clown invigorate their trembling limbs, by whistling, or singing, as they pass by a country churchyard, and the soldier feels his departing courage recalled in the onset of a battle, by the "spirit stirring drum." Intoxication is generally attended with a higher degree of life or excitement than is natural. Now sound will produce this effect with a very moderate portion of fermented liquor; hence we find persons much more easily intoxicated and highly excited at public entertainments, where there is music and loud talking, than in private companies, where no auxiliary stimulus is added to that of wine. Persons who are destitute of hearing and seeing, possess life in a more languid state than other people; which is, in a great degree, owing to the want of the stimulus of light and noise. Odours have likewise a very sensible effect in promoting animal life. The effects of these will appear obvious in the sudden revival of life, which they produce, in cases of fainting. The smell of a few drops of hartshorn, or even a burnt feather, has frequently, in a few minutes, restored the system from a state of weakness, bordering upon death, to an equable and regular degree of excitement. All these different stimuli undoubtedly produce the greatest effects upon their proper organs; thus the effect of light is most powerful on the eye; that of sound on the ear; that of food on the stomach, &c. But their effects are not confined to these organs, but extended over the whole body. The excitability exists, one and indivisible, over the whole system; we may call it sensibility, or feeling, to enable us to understand the subject. Every organ, or indeed the whole body, is endowed with this property in a greater or less degree, so that the effects produced by any stimulus, though they are more powerful on the part where they are applied, affect the whole system: odours afford an instance of this; and the prick of a pin in the finger, produces excitement, or a stimulant effect, over the whole body. From what has been said, it must be evident that life is the effect of a number of external powers, constantly acting on the body, through the medium of that property which we call excitability; that it cannot exist independent of the action of these stimuli; when they are withdrawn, though the excitability does not instantly vanish, there is no life, no motion, but the semblance of death. Life, therefore, is constantly supported by, and depends constantly on, the action of external powers on the excitability; without excitability these stimulants would produce no effect, and whatever may be the nature of the excitability, or however abundant it may be, still, without the action of external powers, no life is produced. From what has been said, we may see the reason why life is in a languid state in the morning: It acquires vigour by the gradual and successive application of stimuli in the forenoon: It is in its most perfect state about midday, and remains stationary for some hours: From the diminution or exhaustion of the excitability, it lessens in the evening, and becomes more languid at bed time; when, from defect of excitability, the usual exciting powers will no longer produce their effect, a torpid state ensues, which we call sleep, during which, the exciting powers cannot act upon us; and this diminution of their action allows the excitability to accumulate; and, to use the words of Dr. Armstrong, "Ere morn the tonic, irritable nerves Feel the fresh impulse, and awake the soul." LECTURE X. THE LAWS OF ANIMAL LIFE, CONTINUED. In the last lecture I began to investigate the laws by which living bodies are governed, and the effects produced by the different exciting powers, which support life, upon the excitability, or vital principle. The facts which we examined led us to two conclusions, which, when properly applied, we shall find will explain most of the phenomena of life, both in health, and in disease. The conclusions alluded to, are these: when the exciting powers have acted more feebly, or weakly, than usual, for some time; or when their action is withdrawn, the excitability accumulates, and becomes more powerfully affected by their subsequent action. And, on the contrary, when the action of these powers has been exerted with violence, or for a considerable time, the excitability becomes exhausted, and less fit to receive their actions. A number of facts were mentioned in proof of these conclusions, and a great number more might have been brought forwards, could it have served any other purpose than to have taken up our time, which I hope may be better employed. This exhaustion of the excitability, by stimulants, may either be final, or temporary. We see animals, while the exciting powers continue to act, at first appear in their greatest vigour, then gradually decay, and at last come into that state, in which, from the long continued action of the exciting powers, the excitability is entirely exhausted, and death takes place. We likewise see vegetables in the spring, while the exciting powers have acted on them moderately, and for a short time, arrayed in their verdant robes, and adorned with flowers of many mingling hues; but as the exciting powers, which support their life, continue to be applied, and some of them, for instance heat, as the summer advances, become increased, they first lose their verdure, then grow brown, and at the end of summer cease to live: because their excitability is exhausted by the long continued action of the exciting powers: and this does not happen merely in consequence of the heat of the summer decreasing, for they grow brown, and die, even in a greater degree of heat than that which in spring made them grow luxuriantly. In some of the finest days of autumn, in which the sun acts with more power than in the spring, the vegetable tribe droop, in consequence of this exhausted state of their excitability, which renders them nearly insensible of the action, even of a powerful stimulus. These are examples of the final or irreparable exhaustion of the excitability; but we find also that it may be exhausted for a time, and accumulated again. Though the eye has been so dazzled by the splendour of light, that it cannot see an object moderately illuminated, yet if it be shut for some time, the excitability of the optic nerve will accumulate again, and we shall again be capable of seeing with an ordinary light. We find also that we are not always equally capable of performing the functions of life. When we have been engaged in any exertion, either mental or corporeal, for some hours only, we find ourselves languid and fatigued, and unfit to pursue our labours much longer. If in this state several of the exciting powers are withdrawn, particularly light and noise, and if we are laid in a posture which does not require much muscular exertion, we soon fall into that state which nature intended for the accumulation of the excitability, and which we call sleep. In this state many of the exciting powers cannot act upon us, unless applied with some violence, for we are insensible to their moderate action. A moderate degree of light, or a moderate noise, does not affect us, and the power of thinking, which very much exhausts the excitability, is in a great measure suspended. When the action of these powers has been suspended for six or eight hours, the excitability is again capable of being acted on, and we rise fresh and vigorous, and fit to engage in our occupations. Sleep then is the method which nature has provided to repair the exhausted constitution, and restore the vital energy. Without its refreshing aid, our worn out habits would scarcely be able to drag on a few days, or at most, a few weeks, before the vital spring would be quite run down: how properly therefore has our great poet called sleep "the chief nourisher in life's feast!" From the internal sensations, often excited, it is natural to conclude, that the nerves of sense are not torpid during sleep, but that they are only precluded from the perception of external objects, by the external organs being in some way or other rendered unfit to transmit to them the impulses of bodies during the suspension of the power of volition; thus the eyelids are closed, in sleep, to prevent the impulse of light from acting on the optic nerve; and it is very probable that the drum of the ear is not stretched; it seems likewise reasonable to conclude, that something similar happens to the external apparatus of all our organs of sense, which may make them unfit for their office of perception during sleep. The more violently the exciting powers have acted, the sooner is sleep brought on, because the excitability is sooner exhausted, and therefore sooner requires the means of renewing it: and, on the contrary, the more weakly these powers have acted, the less are we inclined to sleep. Instances of the first are, excess of exercise, strong liquors, or study; and of the latter, an under or deficient proportion of these. A person who has been daily accustomed to much exercise, whether mental or corporeal, if he omit it, will find little or no inclination to sleep; this state may however be induced by taking some diffusible stimulus, as a little spirits and water, or opium, which seem to act entirely by exhausting the excitability, to that degree which is compatible with sleep, and, when the stimulant effect of these substances are over, the person soon falls into that state. But though the excitability may have been sufficiently exhausted, and the action of external powers considerably moderated, yet there are some things within ourselves, which often stimulate violently, and prevent sleep, such as pain, thirst, and strong passions and emotions of the mind. These all tend to drive away sleep, by their vehement stimulating effect, which still has power to rouse the excitability to action, though it has been considerably exhausted. The best method of inducing sleep, in these cases, is to endeavour to withdraw the mind from these impressions, particularly from uneasy emotions, by employing it on something that makes a less impression, and which does not require much exertion, or produce too much commotion; such as counting to a thousand, or counting drops of water which fall slowly; by listening to the humming of bees, or the murmuring of a rivulet. Virgil describes a situation fitted to induce sleep, most beautifully, in the following words. "Fortunate senex, hic inter flumina nota, Et fontes sacros, frigus captabis opacum. Hinc tibi, quae semper vicino ab limite sepes Hyblaeis apibus florem depasta salicti, Seape levi somnum suadebit inire susurro." In infancy much sleep is required; the excitability, being then extremely abundant, is soon exhausted by external stimulants, and therefore soon requires renewing or accumulating; on this account, during the first five or six months of their life, children require this mode of renewing their exhausted excitability several times in the day; as they advance in years, and as this excess of excitability is exhausted by the application of stimulants, less sleep is required: in the prime of life least of all is necessary. There is great difference however, in this respect, in different constitutions. Some persons are sufficiently refreshed by three or four hours sleep, while others require eight or ten hours. More however depends, in my opinion, on the mode of living. Those who indulge in the use of spirituous or fermented liquors, which exhaust the excitability to a great degree, require much more sleep than those who are content with the crystal stream. The latter never feel themselves stupid or heavy after dinner, but are immediately fit to engage in study or business. As age advances, more sleep is again required; and the excitability at last becomes so far exhausted, and the system so torpid, that the greatest portion of gradually expiring life is spent in sleep. Temperance and exercise are the most conducive to sound healthy sleep, hence the peasant is rewarded, for his toil and frugal mode of life, with a blessing, which is seldom enjoyed by those whom wealth renders indolent and luxurious. The poor in the country enjoy sound and sweet sleep: forced by necessity to labour, their excitability becomes exhausted in a proper and natural manner, and they retire to rest early in the evening. Their sleep is generally sound, and early in the morning they find themselves recruited, and in a state fit to resume their daily labour. The blooming complexion, strength, and activity, of these hardy children of labour, who recruit their wearied limbs on pallets of straw, form a striking contrast with the pallid and sickly visage, and debilitated constitution of the luxurious and wealthy, who convert night into day, and court repose in vain on beds of down. Nature undoubtedly intended that we should be awake, and follow our occupations, whether of pleasure or business, during the cheering light of day, and take repose when the sun withdraws his rays. All other animals, and even vegetables, obey the command of nature: man alone is refractory; but nature's laws are never violated with impunity. Dr. Mackenzie very properly observes, that those who sleep long in the morning, and sit up all the night, injure the constitution without gaining time: and those who do this merely in compliance with fashion, ought not to repine at a fashionable state of bad health. From what has been said, it is evident that, in order to enjoy sound sleep, our chambers should be free from noise, dark, and moderately cold; because the stimulant effects of noise, light, and heat, prevent the accumulation of excitability: and as we shall afterwards see that this accumulation depends on free respiration, and the introduction of oxygen by that means into the system, our bed rooms ought to be large and airy, and, in general, the beds should not be surrounded by curtains. We may from this likewise see the reason why it is so desirable to sleep in the country, even though we are obliged to spend the day in town. These observations on sleep have however led me a little from the direct road; but I thought they could not be better introduced than here. I shall now return to the subject of our more immediate inquiry. By induction we have discovered two of the principal laws by which living bodies are governed: the first is, that when the ordinary powers which support life have been suspended, or their action has been lessened for a time, the excitability, or vital principle, accumulates, or becomes more fit to receive their actions; and secondly, when these powers have acted violently, or for a considerable time, the excitability is exhausted, or becomes less fit to receive their actions. There are therefore three states in which living bodies exist. First, a state of accumulated excitability. Secondly, a state of exhausted excitability. Thirdly, when the excitability is in such a state as to produce the strongest and most healthy actions, when acted upon by the external powers. From what has been said, it must be evident that life depends continually on the action of external powers on the excitability, and that by their continued action, if they be properly regulated, the excitability will be gradually, and insensibly exhausted, and life will be resigned into the hands of him who gave it, without a struggle, and without a groan. We see then that nature operates in supporting the living part of the creation, by laws as simple and beautiful as those by which the animated world is governed. In the latter we see the order and harmony which is observed by the planets, and their satellites, in their revolution round the great source of heat and light; "---------- all combin'd And ruled unerring, by that Single Power, Which draws the stone projected, to the ground. In the animated part of the creation, we observe those beautiful phenomena which are exhibited by an almost infinite variety of individuals; all depending upon, and produced by one simple law; the acting of external powers upon their excitability. I cannot express my admiration of the wisdom of the Creator better than in the words of Thomson. "O unprofuse magnificence divine! O wisdom truly perfect! thus to call From a few causes such a scheme of life; Effects so various, beautiful, and great." Life then, or those functions which we call living, are the effects of certain exciting powers acting on the excitability, or property distinguishing living from dead matter. When these effects, viz. the functions, flow easily, pleasantly, and completely, from the action of these powers, they indicate that state which we call health. We may therefore, as we before hinted, distinguish three states of the irritable fibre, or three different degrees of excitability, of which the living body is susceptible. 1. The state of health which is peculiar to each individual, and which has been called by Haller, and other physiologists, the tone of the fibre. This is produced by a middle degree of stimulus acting upon a middle degree of excitability: and the effect produced by this action, we call excitement. 2. The state of accumulation, produced by the absence or diminished action of the accustomed stimuli. 3. The state of exhaustion, produced by the too powerful action of stimuli; and this may be produced either by the too powerful, or long continued action of the common stimulants which support life, such as food, air, heat, and exercise; or it may be caused by an application of stimulants, which act more powerfully on the excitability, and which exhaust it more quickly, such as wine, spirits, and opium, musk, camphor, and various other articles used in medicines. The state of health, or tone, if we use that term, consists therefore in a certain quantity or energy of excitability necessary to its preservation. To maintain this state, the action of the stimuli should be strong enough to carry off from the body the surplus of this irritable principle. To obtain this end, a certain equilibrium is necessary between the excitability and the stimuli applied, or the sum of all the stimuli acting upon it must be always nearly equal, and sufficient to prevent an excess of excitability, but not so strong as to carry off more than this excess. It is in this equilibrium between the acting stimuli and the excitability, that the health, or tone of the living body consists. When the sum of the stimuli, acting on the body, is so small, as not to carry off the excess of excitability, it accumulates, and diseases of irritability are produced. Of this nature are those diseases to which the poor are often subject, and which will be particularly considered hereafter. When the sum of the stimuli acting on the body, is too great, it is deprived not only of the excess of excitability, but also of some portion of the irritable principle necessary for the tone of the body: or, to speak more distinctly, the body loses more excitability than it receives, and of course must, in a short time, be in a state of exhaustion. This gives rise to diseases which afflict drinkers, or those who indulge in any kind of intemperance, or persons born in climates where the temperature is moderate, but who emigrate to those which are much warmer. Thus we have endeavoured, after the example of Dr. Brown, to ascertain the cause of the healthy state, before the causes of diseases were investigated; and though this is contrary to the general practice, yet it must be evident to every one, that unless we are acquainted with the causes of good health, it will be impossible for us to form any estimate of those variations from that state, called diseases: hence it is that a number of diseases, which have been brought on merely by the undue action of the exciting powers, such as gout, rheumatism, and the numerous trains of nervous complaints, which were by no means understood, may be easily and satisfactorily explained, and as easily cured, by restoring the proper action of these powers, and bringing the excitability to its proper state. As this theory, therefore, is so important, not only in respect to the preservation of health, which nearly concerns every individual, but to the cure of diseases, which is the province of the physician, I have endeavoured to explain it as fully and minutely as possible; to make it still plainer we may perhaps make use of the following illustration. Suppose a fire to be made in a grate or furnace, filled with a kind of fuel not very combustible, and which could only be kept burning by means of a machine, containing several tubes placed before it, and constantly pouring streams of air into it. Suppose also a pipe to be fixed in the back of the chimney, through which a constant supply of fresh fuel is gradually let down into the grate, to repair the waste occasioned by the combustion kept up by the air machine. The grate will represent the human body; the fuel in it the life or excitability, and the tube behind, supplying fresh fuel, will denote the power of all living systems, constantly to regenerate or produce excitability; the air machine, consisting of several tubes, may denote the various stimuli applied to the excitability of the body; the flame produced in consequence of that application, represents life; the product of the exciting powers acting upon the excitability. Here we see, that flame, like life, is drawn forth from fuel by the constant application of streams of air, poured into it from the different tubes of the machine. When the quantity of air poured in through these different tubes is sufficient to consume the fuel as it is supplied, a constant and regular flame will be produced: but if we suppose that some of them are stopped, or that they do not supply a sufficient quantity of air, then the fuel will accumulate, and the flame will be languid and smothered, but liable to break out with violence, when the usual quantity of air is supplied. On the contrary, if we suppose a greater quantity of air to rush through the tubes, then the fuel will be consumed or exhausted faster than it is supplied; and in order therefore to reduce the combustion to the proper degree, the quantity of air supplied must be diminished, and the quantity of fuel increased. If we suppose one of the tubes, instead of common air, to supply oxygen gas, it will represent the action of wine, spirits, ether, opium, and other powerful stimulants upon the body: a bright and vivid flame will be produced, which however will only be of short duration, for the fuel will be consumed faster than it is supplied, and a state of exhaustion will take place. We may carry this illustration still further, and suppose that the air tubes exhaust the fuel every day faster than it can be supplied, then it will be necessary at night to stop up some of the tubes, so that the expense of fuel may be less than its supply, in order to make up for the deficiency. When this is made up, the tubes may in the morning be opened, and the combustion carried on during the day as usual. This will illustrate the nature of sleep. In speaking of this subject, it was observed, that the more violently the exciting powers have acted, the sooner is sleep brought on; because the excitability is sooner exhausted. In the same way the more the air rushes through the tubes, the sooner will the fuel be consumed, and want replenishing. When the exciting powers have acted feebly, a person feels no inclination to sleep, because the excitability is not exhausted to the proper degree, and therefore does not want accumulating. But any diffusible stimulus, as spirits, or opium, will soon exhaust it to the proper degree. In the same way, if the air have not passed rapidly through the tubes, the fuel will not be exhausted: but it may be brought to a proper degree of exhaustion by the application of oxygen gas. When the air which nourishes the flame is so regulated, that it consumes the fuel as it is supplied, but no faster, a clear and steady flame will be kept up, which will go on as long as the fuel lasts, or the grate resists the action of the fire: but at last when the fuel, which we do not suppose inexhaustible, is burnt out, the fire must cease. In the same manner, if the different exciting powers which support life were properly regulated, all the functions of the body would be properly performed, and we should pass our life in a state of health, seldom known to any but savages, and brute animals not under the dominion of man, who regulate these powers merely by the necessities of nature. When air is applied in too great quantity, and especially if some of the tubes convey oxygen gas, then a violent combustion and flame is excited, which will, in all probability, consume or burn out the furnace or grate, or if it do not, it will burn out the fuel, and thus exhaust itself. In like manner, if the stimulants which support life be made to act too powerfully, and particularly if any powerful stimulus, not natural to the body, such as wine or spirits, be taken in too great quantity, a violent inflammatory action will be the consequence, which may destroy the human machine: but if it do not, it will exhaust the excitability, and thus bring on great debility. This analogy might be pursued further, but my intention was solely to illustrate some of the outlines of our theory, by a comparison which may facilitate the conception of the manner in which external powers act on living bodies. The different powers which support life, and without whose action we are unable to exist, such as heat, food, air, &c. have been very improperly called nonnaturals, a term which is much more applicable to those substances which we are daily in the habit of receiving into the system, which excite it to undue actions, and which nature never intended we should receive; such as spirituous and fermented liquors, and high seasoned foods. In the preceding illustration, I have spoken of a tube, as constantly pouring in fresh fuel, because it was not easy otherwise to convey a familiar idea of the power which all living systems possess of renewing their excitability, when exhausted. The excitability is an unknown somewhat, subject to peculiar laws, some of which we have examined, but whose different states we are obliged to describe, though, perhaps, inaccurately, by terms borrowed from the qualities of material substances. Though Dr. Brown very properly declined entering into the consideration of the nature of excitability, or the manner in which it is produced, the discoveries which have been made in chemistry since his time, have thrown great light on the subject, and it is now rendered highly probable that the excitability or vital principle, is communicated to the body by the circulation, and is intimately connected with the process of oxidation. Many circumstances would tend to show, that a strict connexion exists between the reception of oxygen into the body, and the vital principle. When an animal has been killed by depriving it of oxygen gas, the heart and other muscles, and indeed the whole system, will be found completely to have lost its excitability. This is not the case when an animal is killed in a different manner. When an animal is shot, or killed in the common manner, by bleeding to death, if the heart be taken out, it will contract for some hours, on the application of stimulants. But this is not the case with an animal that has been drowned, or killed by immersion in carbonic acid, azotic, or hydrogenous gases; in these last instances, the heart either does not contract at all, or very feebly, on the application of the strongest stimulants. We have already seen that oxygen unites with the blood in the lungs, during respiration: by the circulation of the blood it is distributed to every part of the system, and we shall find, that in proportion to its abundance is the excitability of the body. In proof of this, I shall relate some facts and experiments. Dr. Girtanner injected a quantity of very pure oxygen gas into the jugular vein of a dog: the animal raised terrible outcries, breathed very quickly, and with great difficulty: by little and little his limbs became hard and stiff, he fell asleep, and died in the course of a few minutes afterwards. It ought here to be observed, that any of the gases, or almost any fluid, however mild, when thus suddenly introduced into the circulating system, generally, and speedily, occasions death. On opening the chest, the heart was found more irritable than ordinary, and its external contractions and dilatations continued for more than an hour: the right auricle of the heart, which usually contains black venous blood, contained, as well as the right ventricle, a quantity of blood of a bright vermilion colour; and all the muscles of the body were found to be more than usually irritable. This experiment not only proves that the vermilion colour of the blood proceeds from oxygen, but likewise seems to show, that oxygen is the cause of excitability. A quantity of azotic gas, which had been exposed for some time to the contact of lime water, in order to separate any carbonic acid gas it might contain, was injected into the jugular vein of a dog. The animal died in twenty seconds. Upon opening the chest, the heart was found filled with black and coagulated blood: this organ, and most of the muscles had nearly lost the whole of their irritability, for they contracted but very weakly, on the application of the strongest stimulants. A quantity of carbonic acid gas was injected into the jugular vein of a dog: the animal became sleepy, and died in about a quarter of an hour: the heart was found filled with black and coagulated blood, and had lost the whole of its irritability; neither it, nor any of the muscles producing any contractions, upon the application of stimulants. Humboldt likewise mentions a curious fact, which tends strongly to confirm this idea. When the excitability of the limb of a frog had been so far exhausted, by the application of zinc and silver, that it would produce no more contractions, on moistening it with oxygenated muriatic acid, the contractions were renewed. After the excitability of the sensitive plant (mimosa pudica) had been so far exhausted, by irritation, that it ceased to contract, when further irritated, I restored this excitability, and brought it to a very high degree of irritability, by moistening the earth in which it grew with oxygenated muriatic acid. Seeds likewise vegetate more quickly when moistened with this acid, than when they are not. In short, we shall find, first, that every thing which increases the quantity of oxygen in organized bodies, increases at the same time their excitability. Secondly, That whatever diminishes the quantity of oxygen, diminishes the excitability. The excitability of animals, made to breathe oxygen gas, or to take the oxygenated muriate of potash, or acid fruits, is very much increased. On the contrary, when persons have inspired carbonic acid, or azotic gas, or have taken into the system substances which have a strong affinity for oxygen, and therefore tend to abstract it, such as hydrogen, and spirits, the excitability becomes very much diminished. When we sleep, in consequence of the excitability being exhausted, the breathing becomes free, and a great quantity of oxygen is received by the lungs, and combined with the blood, while very little of it becomes exhausted by the actions of the body, for none, excepting those which are called involuntary motions, are carried on during sound sleep: so that in a few hours the body recovers the excitability which it had lost: it is again sensible of the impressions of external objects, and with the return of light we wake. These facts afford satisfactory proofs that the excitability of the body is proportioned to the oxygen which it receives: but in what manner it produces this state of susceptibility, and how it is exhausted by stimulants, we have yet to learn. The following theory may perhaps throw some light upon the subject. I propose it, however, merely as an hypothesis, for we have no direct proofs of it, but it seems to account for many phenomena. It is now well known, that while the limb of an animal possesses excitability, the smallest quantity of electricity sent along the principal nerve leading to it, produces contractions similar to those produced by the will. This is instanced in the common galvanic experiment with the limb of a frog, which I had formerly occasion to show. From the effects produced, when a stream of electricity is sent through water, I think it not improbable that hydrogen and electricity may be identical. When a piece of zinc and silver are connected together, and the zinc is put in a situation to decompose water, and oxidate, a current of hydrogen gas will separate from the silver wire, provided this be immersed under water; but when it is not, a current of electricity passes, which is sensible to the electrometer. Now there appears no greater improbability in the supposition that hydrogen, in a certain state, may be capable of passing through metals, and animal substances, in the form of electricity, and that when it comes in contact with water, which is not so good a conductor, it may combine with caloric, and form hydrogen gas, in which state it becomes incapable of passing through the conductors of electricity: I say there appears no greater improbability in this, than that caloric should sometimes be in such a state, that it will pass through metals, and animal substances, which conduct it, and at other times, as when combined with oxygen or hydrogen, it should form gases, and be then incapable of passing through these conductors of heat. Galvanic effects may be produced by the oxidation of fresh muscular fibre without the aid of metals, and contractions have been thus produced in the limb of an animal; and we have already noticed, that when this contraction ceases, it may be restored, by moistening the limb with oxygenated muriatic acid. The excitability of the body may, most probably, be conveyed by respiration, and the circulation of the blood, which tend continually to oxidate the different parts: and hydrogen or electricity may be secreted by the brain, and sent along the nerves, which are such good conductors of it, and by uniting with the oxygen of the muscle, may cause it to contract; but as the oxygen will, by this union, be diminished, if the contractions be often repeated, the excitability will thus be expended faster than it can be supplied by the circulation, and will become exhausted. But will facts bear us out in this explanation? To see this, we must examine the chemical nature of the substances which produce the greatest action, and the greatest exhaustion of the vital principle: namely, those which produce intoxication. Fermented liquors differ from water, in containing carbon and more hydrogen: these produce intoxication: but pure spirits, which contain still more hydrogen, produce a still higher degree of intoxication, and consequent exhaustion of the excitability. Ether, which appears to be little more than condensed hydrogen, probably kept in a liquid state by union with a small quantity of carbon, and which easily expands by caloric into a gas, which very much resembles hydrogen gas, produces a still greater degree of intoxication: so that we see the action produced by different substances, as well as the exhaustion of excitability which follows, is proportioned to the quantity of hydrogen they contain. There is another circumstance which seems to strengthen this idea. The intoxicating powers of spirits are diminished by the addition of vegetable acids, or substances which contain oxygen, which will counteract the effects of the hydrogen. Thus it is known that the same quantity of spirit, made into punch, will not produce either the same ebriety, or the same subsequent exhaustion, as when simply mixed with water. Recollect however that I propose this only as a hypothesis: its truth may be confirmed by future observations and experiments, or it may be refuted by them: but it is certainly capable of explaining many of the phenomena, which is one of the conditions required by Newton's first rule of philosophizing. Heat, and light, and other stimuli, may perhaps exhaust the excitability, by facilitating the combination of oxygen in the fibres with the hydrogen and carbon in the blood. There are several substances which cause a diminution or exhaustion of the excitability, without producing any previous increased excitement. These substances have by physicians been called sedatives: and though the existence of such bodies is denied by Dr. Brown, yet we are constrained to admit them; nor do their effects seem incapable of being explained on the principle laid down, especially if we call in the aid of chemistry. Any substance which is capable of combining rapidly with oxygen, and diminishing its quantity, will be a sedative. But the action of some of the animal and vegetable poisons is difficult to explain in the present state of our knowledge; such very minute portions of these produce great exhaustion of the excitability, and even death, that we can scarcely explain their action on the supposition that they combine with the oxygen. They may perhaps act as ferments, and occasion throughout the whole system a new and rapid combination of oxygen with the hydrogenous, carbonic, and perhaps azotic parts of the blood and fluids, and even of the solids, which will speedily destroy the excitability, and even the organization. Many of the vegetable narcotics, though they will destroy life when given in considerable doses, yet when exhibited in less quantities become very powerful remedies, particularly in cases where the excitability is accumulated, in consequence of which violent spasms and inordinate actions take place, which are very quickly calmed by opium, camphor, musk, asafoetida, ether, &c. medicines that occasion a speedy exhaustion of the excitability. In diseases of exhaustion, however, these remedies are improper. The indication here is to accumulate the irritability, by the introduction of oxygen, and by the diminution of the action of the stimulants which support life. In this idea too I dissent from Dr. Brown, who taught that diseases of exhaustion are to be cured by stimulants, a little less powerful than those which produced the disease. This subject will however be more fully discussed hereafter. This doctrine of animal life, which I have been attempting to illustrate, and render familiar, exhibits a new view of the manner in which it is constantly supported. It discovers to us the true means of promoting health and longevity, by proportioning the number and force of stimuli to the age, climate, situation, habits, and temperament, of the human body. It leads us to a knowledge of the causes of diseases: these we shall find consist either in an excessive or preternatural excitement in the whole or part of the human body, accompanied generally with irregular motions, and induced by natural or artificial stimuli, or in a diminished excitement or debility in the whole, or in part. It likewise teaches us that the natural and only efficacious cure of these diseases depends on the abstraction of stimuli, from the whole, or from a part of the body, when the excitement is in excess: and in the increase of their number and force when the contrary takes place. The light which the discoveries of Galvani, and others who have followed his steps, begin to throw on physiology, promises, when aided by the principles of chemistry, and the knowledge of the laws of life, to produce all the advantages that would result from a perfect knowledge of the animal functions. From what has been said, it does not seem improbable that muscular contraction may depend upon the combination of oxygen with hydrogen and azote, in consequence of a sort of explosion or discharge produced by nervous electricity. According to this hypothesis, animal motion, at least that of animals analogous to man, would be produced by a beautiful pneumatic structure. This hypothesis, though not perhaps at this moment capable of strict demonstration, seems extremely probable, it being countenanced by every observation and experiment yet made on the subject. It accounts likewise for the perpetual necessity of inhaling oxygen, and enables us to trace the changes which this substance undergoes, from the moment it is received into the system, till the moment it is expelled. By the lungs it is imparted to the blood; by the blood to the muscular fibres; in these, during their contraction, it combines with the hydrogen, and perhaps carbon and azote, to form water and various salts, which are taken up by the absorbents, and afterwards exhaled or excreted. We know the necessity of oxygen to muscular motion, and likewise that this motion languishes when there is a deficiency of the principle, as in sea scurvy. Thus a boundless region of discovery seems to be opening to our view: the science of philosophy, which began with remote objects, now promises to unfold to us the more difficult and more interesting knowledge of ourselves. Should this kind of knowledge ever become a part of general education, then the causes of many diseases being known, and the manner in which the external powers, with which we are surrounded, act upon us, a great improvement not only in health, but in morality must be the consequence. With respect to its influence on the science of medicine, we may observe that, from the time of Hippocrates till almost the present day, medicine has not deserved the name of a science but, as he called it, of a conjectural art. At present however, by the application of the laws of life, and of the new chemistry, there is beginning to appear in physiology and pathology, something like the simplicity and certainty of truth. In proportion as the laws of animal nature come to be ascertained, the study of them will excite more general attention, and will ultimately prove the most popular, as well as the most curious and interesting branch of philosophy. This must be productive of beneficial consequences to society, since these truths, once impressed upon the mind by conviction, will operate as moral motives, by which the sum of disease and human misery cannot fail to be greatly diminished. LECTURE XI. OF THE NATURE AND CAUSES OF DISEASES. In the two last lectures I have attempted to investigate the laws of life. I now proceed to the most important part of our course, and for which all the preceding lectures were intended to prepare us; I mean the application of the laws of life to explain the nature and causes of diseases, and the methods of curing them, which must always be imperfect, and conjectural, unless the nature of the diseases themselves be well understood. We have already seen that life is constantly supported by the action of the external powers which surround us, and that if the action of these powers be properly regulated, and at the same time no other powers be suffered to act on the body, we shall enjoy perfect health, but if, on the contrary, the exciting powers which support life, act either too feebly or too powerfully, then the functions will not be performed with precision and vigour, but irregularly; the mind and body will become deranged, and death will often take place many years before the natural period at which that event might be expected. As health is the greatest blessing which man can enjoy, it is natural to think, that in the early ages of society, when men began to lose sight of the dictates of nature, and feel the torture of disease, they would regard with gratitude those who had contributed towards their relief, and that they would place their physicians among their heroes and their gods. In the early ages, however, diseases would be very few, for it would not be till civilisation had made considerable progress, that such unnatural modes of life as conduce to their production, would take place. As the first professors of physic knew nothing of the animal economy, and little of the theory of diseases, it is evident that whatever they did, must have been in consequence of mere random trials. Indeed it is impossible that this or any other art could originate in any other manner. Accordingly history informs us that the ancient nations used to expose their sick in temples, and by the sides of highways, that they might receive the advice of every one that passed. It would take up too much time to pursue the history of medicine from this rude origin, through all its changes and revolutions, till the present time: let it therefore suffice to say, that after various theories had been invented and overturned, and after one age had destroyed the labours of another, though different branches of the healing art, and particularly anatomy, had been enriched with valuable discoveries, still a rational theory was wanting; there was nothing to guide the practitioner in his way, and we may truly say that till the laws of life, which I have been endeavouring to illustrate, were investigated by Dr. Brown, medicine could boast of no theory which had a title to be called philosophical. The theories of Stahl, Boerhaave, and Cullen, have passed away, and are almost forgotten, but this, which is founded on nature, and on fact, will, like the Newtonian philosophy, last for ever. It has already influenced the practice of medicine, and is taught in almost all the schools of Europe and America. In this country it seems to have had less attention paid to it than it deserved, because its influence was counteracted by the arrogance and profligacy of its author, as if the grossness of a man's manner affected the conclusiveness of his arguments; but this influence did not extend beyond Britain, while the light of his theory illuminated the opposite hemisphere. And when the manner in which he was persecuted is recollected, the liberal mind will allow something to the deep consciousness of neglected merit. A circumstance much in favour of this doctrine is, that those who understand its principles thoroughly, are guided by it in their practice with a certainty and success before unknown. I say those who understand its principles, for these were not perfectly understood even by the author himself. He first saw with his mind's eye the grand outline of the system, from which, for want of proper reflection, he often drew wrong deductions, and which he often applied improperly. But whatever errors Brown may have committed in the application of his system, and however short his doctrines may fall of a perfect system of medicine, we may venture to predict that the grand outlines will remain unshaken. From what has been already shown, it must be evident that if the just degree of excitement could be kept up, mankind would enjoy continual health. But it is difficult, if not impossible, to regulate the action of the exciting powers in this equable manner, and if their action is increased, the first effect they produce on the functions is to increase them, and the next is, to render them disturbed or uneasy; or, in other words, to bring on diseases of increased action, or what have been called inflammatory or phlogistic, both of which terms are improper, as they convey false ideas, and are connected with erroneous theories: Dr. Brown has given the name of sthenic to these diseases, from their consisting in increased strength or action, and this is certainly a more appropriate term. On the contrary, when the action of the exciting powers is diminished more than is natural, the functions become languid and disturbed, and by a still further decrease of the action of these powers, they become irregular and inordinate. This state of the body, which is opposite to the former, Dr. Brown has denominated asthenic. But the stimulant powers may act so powerfully, and exhaust the excitability to such a degree, that they may overstep the bounds of sthenic or inflammatory disease and bring on debility. Debility may therefore arise either from the stimuli acting too weakly, or from a deficient excitability, while the stimulus is not deficient. Debility produced in the former manner is called direct debility, and in the latter indirect debility. To explain this more clearly, let us take a common instance. If a person by any means be deprived of the proper quantity of food, he will feel himself enfeebled, and the functions will gradually grow more and more languid, and at last become irregular, and be performed with pain. This state is called direct debility. Here is excitability enough, and even too much, for it has accumulated by the subtraction of a stimulus; but here is a deficiency of excitement from defect of stimulus. If now we suppose that a person, in good health, begins to take a greater quantity of food than usual, and adds a quantity of wine, all the functions will at first be increased in vigour, but at last they will be irregularly performed, and inflammation, with other symptoms of too great excitement, will be the consequence. This state is called sthenic diathesis or disease. But if the stimulant power be pushed still further, the excitability will become gradually exhausted, till at last there will be too little to produce the healthy actions, even though there may be plenty of stimulus. This state of asthenic diathesis is called indirect debility, because it is not produced by directly subtracting the powers which support life, but indirectly, by over stimulating. An instance of this latter state is afforded by that debility which is the consequence of intoxication. There is a state however between perfect health and disease, which is called predisposition; and in which, though the functions are undisturbed, the slightest cause will bring on disease. Strictly speaking, there is perhaps only one point, or one degree of excitement, at which the health is perfect: the first alterations from this point, on either side, are scarcely perceptible, but if the morbid causes be continued, the functions will become gradually more and more disturbed, till at last they become so uneasy or painful that they are termed disease. In order to render what has been said still more plain, it may be proper to make use of an illustration by means of numbers: we must recollect however that it is merely for the sake of illustration, for we have not data to enable us to reduce either the excitability, or excitement, or stimulus, to numerical calculation; if we could do this, the science of medicine would be perfect, and we could cure diseases as easily as we could perform any chemical or philosophical experiment. A very principal object however is to understand the nature of predisposition, and the kind of diathesis, whether sthenic or asthenic, to which it inclines: this not only throws light on the nature of the disease, but affords us the only means of preventing it. When a slight uneasiness or predisposition is felt, it is almost impossible to say from our feelings whether it leads to a sthenic or an asthenic state: here we must be guided chiefly by the exciting powers. If we find that these have acted too powerfully; that is, if we have lived freely, been exposed to heat, and perhaps indulged in some of the unnatural stimuli, such as wine and spirits; and particularly if we previously to the present time perceived the functions to go on with more vigour, our spirits and strength greater, before we experienced the slight disturbance of which we complain, we are verging towards sthenic or inflammatory disease, and therefore to prevent the disease we ought immediately to diminish the action of the exciting powers; the quantity of food ought to be diminished, wine and other liquors abstained from, heat carefully avoided; and even the quantity of blood in the circulating system diminished, if the habit is full and the pulse strong. On the contrary, if the exciting powers have acted more feebly than is natural; that is, if we have lived on a less nourishing diet, or have taken it in less quantity; if we have been long exposed to cold, without alternating with heat, and other debilitating causes; and if at the same time we find the vigour of the functions diminished, though they are not yet become much disturbed, we are verging towards asthenic disease. To prevent which, we must take a more nutritious diet, and join a portion of wine, and perhaps take some tonic medicines. This however ought to be done gradually, for fear of exhausting the excitability, which in these cases is morbidly accumulated. It must be evident that the great difficulty here is to determine the nature of the predisposition; for if we make a mistake, instead of preventing, we shall accelerate the disease. For instance, the first slight disturbance of the functions which rises from a sthenic state, often resembles those verging towards a state of debility or asthenia. I have seen various instances arising from plethora, or a sthenic state, where the patient complained of depression of spirits, and inability to move; and, in short, from his own account was labouring under asthenic diathesis: but by inquiring carefully into the action of the exciting causes, examining minutely the state of the pulse and of the functions, I have been convinced that the depression of spirits which he felt, and other symptoms of weakness, depended on fullness, and they have been quickly removed by lowering the diet, administering a laxative, or taking a little blood: whereas if, apprehending from the symptoms that he had laboured under debility, I had ordered him a more generous diet and tonic remedies, an inflammatory disease would have been the consequence, which might have terminated in death. I have seen various instances where patients have complained of this unusual depression, and inability to move: they have shown me prescriptions in which the stimulant or tonic plan was recommended, but instead of any alleviation the symptoms had become worse from their use. This hint was generally sufficient, for if the disease of predisposition had been asthenic, cordials and tonics ought to have relieved it: if, on inquiry, I found the exciting powers had acted too powerfully, I then, without hesitation, had recourse to the debilitating plan, and with the greatest certainty of success. Before I viewed diseases and their causes in this way, I must confess that I often felt great hesitation in practice; and judging merely from symptoms, which are frequently very fallacious, the operation of a remedy often disappointed me, and I could not pretend to predict the event with the certainty that I now can. This observation is of the greatest consequence in the cure both of predisposition and of disease. Though excitement regulates all the phenomena of life, yet the symptoms of diseases which either its excess or deficiency produces, do not of themselves lead to any proper judgment respecting it. On the contrary their fallacious appearance has proved the source of infinite error. As excitement both depends on exciting powers and excitability, it is evident that when a middle degree of stimulus acts upon a middle degree of excitability, the most perfect effect will be produced. This point, could we ascertain it, might be called the point of health. For the sake of illustration, we may suppose that the greatest excitability of which the living body is capable is 80 degrees: this may be supposed to be the excitability possessed by the body at the commencement of its life, because no part has then been wasted or exhausted by the action of stimuli. Now, if we suppose a scale of excitability to be formed, and divided into 80 equal parts or degrees, the excitability will be wasted or exhausted in proportion to the application of stimuli, from the beginning to the end of the scale. One degree of exciting power applied takes off one degree of excitability, and every subsequent degree impairs the excitability in proportion to its degree of force. Thus a degree of stimulus or exciting power equal to 10 will reduce the excitability to 70, 20 to 60, 30 to 50, 40 to 40, 50 to 30, 60 to 20, 70 to 10, 80 to 0; and, on the contrary, the subtraction of stimulant power will allow the excitability to accumulate. [DIAGRAM] The range of good health is ranked from 30 to 50 degrees in the scale; for perfect health, which consists in the middle point only, or at 40 degrees, rarely occurs; in consequence of the variation of the stimuli to which man is continually exposed, such as meat and drink, heat, exercise, and the emotions of the mind, the excitement commonly fluctuates between 30 and 50 degrees, and yet no particular disturbance of the functions takes place. But when at these points, 30 or 50, predisposition commences, the slightest debilitating cause in the former case, and the slightest stimulating cause in the latter, brings on disease, in which the functions begin to be disturbed in various ways, and this disturbance is always in proportion to the hurting powers which have produced the disease, and the delicacy or importance of the part affected. The effect produced on the excitability by any stimulus, must evidently be in a ratio compounded of the degree of excitability and the force of the stimulus. The same stimulus will produce greater contractions upon a fibre that is more irritable than upon one which possesses less irritability; and the irritability or excitability of the fibre being given, or remaining the same, the contraction will be in proportion to the strength of the stimulus. Hence it is evident, that the effect or excitement must be in a ratio compounded of the exciting powers and excitability. Sthenic diathesis and disease is caused by the operation of different exciting powers, which produce too great a degree of excitement in the system: this at first increases all the functions, and, when increased, produces a disturbance and inordinate action of them, which is communicated to the whole body. In diseases of this kind there is often an appearance of debility, but this is extremely fallacious, and arises from the disturbed state of the different functions. Hence it is evidently of the utmost consequence to ascertain carefully whether this debility is real, or the effect of asthenic disease: or whether it is owing to the disturbance of the functions by over stimulating, and in this case fallacious; for should a sthenic disease be treated by stimulants and cordials, the effect would be an aggravation of all the symptoms, and a much higher degree of disease. Asthenic diathesis and disease is brought on by the excitement of the system being diminished: and this may proceed either from a diminution of common stimulant powers, while the excitability is sufficiently abundant, or it may proceed from an exhausted excitability, while the stimulus is sufficiently abundant. The former is called direct, and the latter indirect debility. The exciting causes therefore of asthenic disease, first impair the functions, then occasion a disturbed or inordinate action of them, giving many of them a false appearance; some of them, for instance, appear to be increased, for in hysteria and epilepsy, which are both diseases of debility, the action of the muscles seems to be preternaturally increased; but this depends chiefly on the accumulated excitability, which gives such a degree of irritability to the system, that the smallest irritation, whether external, such as heat, exercise, &c. or internal, as emotions of the mind, excite a strong spasmodic action, which brings on the symptoms of epilepsy and hysteria. This inordinate action however soon exhausts the morbid excitability, and thus suspends itself, a sleep often follows, from which the patient wakes with only a general sense of languor and debility: but as the same cause still remains, the excitability of the body again becomes morbidly accumulated, and thus the slightest stimulus produces a recurrence of the fit, and the tendency to return will increase with its recurrence, so that at last the slightest imaginable cause will produce it, on account of the power of habit and association. Gout likewise appears like a sthenic disease, and in inflammation takes place, which resembles pleurisy or peripneumony; but this symptom is fallacious, for it depends on debility, and is only to be cured by means, which in pleurisy and peripneumony, would produce death. Hence it must be evident that those phenomena of diseases, which we call symptoms, are generally fallacious; but this may be owing to our imperfect knowledge of the animal economy, so that we are not able to explain or understand the manner in which they are produced: we ought however carefully to guard against being misled by them in practice. The great difficulty is to distinguish the nature of the disease, whether it is sthenic or asthenic, or whether it depends on too great excitement, or on debility; for this being once clearly ascertained, we proceed with certainty in our mode of treatment, instead of the random practice, which must be the consequence of not taking a proper view of the laws of life, and the causes of diseases. The nature of the disease may be generally ascertained, by attending to the habits of the patient, and the manner in which he has lived, as well as to the state of the pulse; but in cases where these circumstances do not render it clear, it may be ascertained, beyond a doubt, by a trifling degree of stimulus, as, for instance, by any cordial, as a little wine or spirits. If the disease be of an inflammatory or sthenic kind, the symptoms will be aggravated, and the cordial will not produce its usual pleasant effects on the system; but on the contrary, if the nature of the disease be asthenic, then the usual pleasant effects of the cordial will be perceived, and the pain and other symptoms will be alleviated. This trial, which is soon made, and without danger, will determine our plan of cure, and we can then proceed with the most perfect certainty. Thus you will see that this view we have taken leads to a very different and much more rational plan of practice than is generally followed, in which the most judicious physicians confess that they have no clue to guide them; and complain that the science of medicine consists merely in a number of insulated facts, not connected by any theory: that they merely prescribe a remedy because they have seen it of use in an apparently similar state, but that they have no certainty of its producing a similar effect in the cases in which they prescribe it. This all depends on trusting to the fallacious appearance of symptoms, and not having taken a proper view of the laws of life, or the manner in which the exciting powers act on living bodies. After these observations on the diagnosis, or the method of distinguishing the nature of diseases, I shall proceed to consider more particularly the nature of sthenic diseases, and the methods of curing them, which will occupy the remainder of our time this evening. The powers or causes, which by their action produce inflammatory or sthenic diseases, are, first, heat, which is a very frequent cause, particularly when it succeeds cold; for the cold accumulates the excitability, and then renders the whole body, or a part, more liable to be affected by the heat afterwards applied. In this way is produced rheumatism, catarrh, or, as it is commonly called, a cold, and peripneumony. These complaints have been often attributed to cold, but I believe that there never was a well attested instance where cold alone, without being either followed by heat or some other stimulus, produced a real sthenic, or inflammatory disease. This is not merely a distinction, it is a circumstance of the utmost importance, because it influences the mode of practice to be pursued. Heat is one of the exciting or stimulant powers which support life, and one of the most powerful of these stimulants; but cold is only a diminution of it: how then can this produce a sthenic state, or a state of too high excitement? The blood is one of the exciting powers, which, by its continual circulation supports life; but surely if we abstracted a quantity of this fluid from the body, no person will be bold enough to say, that we by that means should produce an inflammatory disease. Cold renders the body more liable to be affected by heat, or any other stimulus applied, but does not of itself produce any stimulant or inflammatory effects. To see more clearly the manner in which cold acts, let us inquire how it produces or contributes towards the production of catarrh. When we go into the cold air, at every respiration we take a quantity of it into the lungs, which brushes over the surface of the mucous membrane that lines the nostrils and trachea, and thus, robbing them of their heat, allows the excitability to accumulate. But we feel no fever, no sense of tightness or stuffing, nor any other symptom of catarrh, so long as we continue in the cold. If however we afterwards go into a warm room, and particularly near a fire, we receive by the act of respiration the warm air into those very parts which have been previously exposed to cold, and whose excitability is consequently accumulated. The first effect we perceive is a glow of the parts, which is by no means unpleasant, this however increases; and, in the course of half an hour or an hour, a sense of dryness and huskiness comes on, with a sensation of stuffing in the nostrils, and a tendency to a short dry cough: often likewise, if the exposure to cold has been considerable, and the heat afterwards applied great and sudden, we experience a shivering, and other symptoms of fever. These symptoms are all increased by taking into the stomach any liquid that is either of warm temperature or stimulating quality, or particularly both; we spend a restless night, and awake with all the symptoms of a catarrh, or cold, as it is improperly called. For it is evidently an inflammatory fever, and can be speedily cured by the debilitating plan, and particularly by keeping in a moderately cool place, where the temperature is equable, and not subject to alternations of heat and cold. But how easily might this complaint have been avoided, were the person subject to it acquainted with its real nature, and the manner in which it is brought on. When we come out of a very cold atmosphere, we should not at first go into a room that has a fire in it; or, if this cannot be well avoided, we should keep for a considerable time at as great a distance from the fire as possible, that the accumulated excitability may be gradually exhausted by the moderate and gentle action of heat; and then we may bear the heat of the fire without any danger; but above all, we should refrain from taking warm or strong liquors while we are hot. In confirmation of this opinion, numerous instances might be brought, where catarrh was cured merely by exposure to cold. When a part of the body only has been exposed to the action of cold, and the rest kept heated; if, for instance, a person in a warm room has been sitting so that a current of air, coming through a broken window, has fallen upon any part of the body, that part will soon be affected with an inflammation, or what is called a rheumatic affection. In this case, the excitability of the part exposed to the action of the cold, becomes accumulated, and the warm blood, rushing through it, from every other part of the body, excites an inflammation. Thus catarrh and rheumatism are inflammatory complaints, or depend on too great a degree of excitement, and are to be cured by lowering the excitement, or diminishing the action of the exciting powers; by bleeding, purging, low diet, and particularly keeping in a moderately cool place; and these complaints will be as speedily and certainly cured by these methods, properly and judiciously persevered in, as a slight cut or wound will be healed by what surgeons call the first intention. There are complaints which resemble these, but whose nature, however, is very different, and which require a very different mode of treatment. After a part has been long affected with rheumatic inflammation the excitability of the muscular fibres becomes so far exhausted, that a state of indirect debility takes place, and an inflammation, accompanied with pain and redness, which is very different from that I formerly described, as it depends upon a debilitated or relaxed state of the parts, instead of too great a degree of excitement. This instance shows strongly the fallacy of symptoms; but it may be readily distinguished from the inflammatory rheumatism, by attention to the effects of the exciting causes. The inflammatory rheumatism is aggravated by heat, hence it is more violent in bed than at any other time. The latter complaint, however, is greatly relieved by heat: the warm bath alleviates all the symptoms; so does a warm bed. It is evident that these diseases, though attended by the same symptoms, are as opposite, and require as different modes of treatment as an inflammation of the brain, and a dropsy. The inflammatory state has been called the acute rheumatism, and the other, the chronic rheumatism; I would, however, prefer the terms sthenic and asthenic rheumatism. In the same manner, there is a catarrh, which is liable to afflict persons who have often been subject to an inflammatory cold, particularly persons advanced in years; and this depends on a state of indirect debility of the parts, the excitability of which has been exhausted by frequent and violent inflammatory affections. This complaint, which I would call asthenic catarrh, requires directly opposite treatment from the inflammatory or sthenic catarrh. The latter is aggravated by heat, but relieved by a cool temperature. Warm air is peculiarly grateful to those who are afflicted with the former, and if they go into a cool temperature, they are immediately seized with cough, and expectoration; for the disease being a disease of debility, the withdrawing the stimulus of heat, must increase it. The excitability of the parts is so far exhausted, that it requires a stimulus even more than natural to keep them in tone: hence persons labouring under asthenic catarrh, and some species of asthma, which are only varieties of this disease, find themselves best when exposed to a warm temperature, but on the heat being diminished, and consequently the parts relaxed, the cough and difficulty of breathing immediately come on. Having examined the effect of heat, in producing inflammatory or sthenic disease, I now proceed to the consideration of the other powers. Of the articles of diet, the only food in danger of being too stimulant, is perhaps flesh or land animal food, used in too great quantity, particularly when seasoned, a preparation which adds much to its stimulant power. Spirituous and vinous liquors, let them be ever so weak or much diluted, stimulate more quickly, and more readily than seasoned food, and their stimulus is in proportion to the quantity of alcohol which they contain. These substances, when conjoined with rich food, must bring on a predisposition to sthenic disease, in almost any constitution, particularly in the young and healthy, and, in many instances, those diseases actually take place; or should this not be the case, should the person avoid, or escape the effects of inflammatory diseases, the excitability will be exhausted, and diseases of indirect debility, such as gout, apoplexy, indigestion, palsy, &c. will take place. These stimulants are never necessary to a good constitution, and their effects will always, sooner or later, be experienced: for though a person with a good constitution may continue for years to indulge in the pleasures of the bottle, or the luxuries of the table, depend upon it that a continuance of them will sap the vigour of the strongest constitution that ever existed. As nothing contributes more to the health of the body than moderate and frequently repeated exercise, which rouses the muscles to contraction, and promotes the circulation of the blood in the veins towards the heart: it thus produces excitement; but an excess of it will produce sthenic diathesis; and, if carried to great excess, it will produce a state of indirect debility, or exhausted excitability. When any, or all of these exciting powers act too strongly on the body, the first effect they produce is a preternatural acuteness of all the senses; the motions, both voluntary and involuntary, are performed with vigour, and there is an acuteness of genius and intellectual power. In short, every part of the body seems in a state of complete vigour and strength; that this is the case with the heart and arteries, appears from the strong and firm pulse; in the stomach it is shown by the appetite; and, in the extreme parts, by the ruddy colour and complexion. In short, every appearance marks vigour of the body, and abundance of blood. Could the body be kept in this state, nothing could be more to be desired; this, however, is impossible; the excitement, though still within the bounds of health, has overstepped the point of good health, and is verging fast to predisposition to sthenic disease; so that, to secure a permanent state of health, it is always better to keep the excitement rather under the middle point, or 40 degrees, than above it. During the predisposition to sthenic disease, which is produced by the longer continued, or increased action of these powers, no symptoms of disease appear; but shortly after, disturbed sleep, depressed spirits, languor, a sense of fulness, heaviness, particularly after eating, show that this sthenic state cannot be further increased with impunity. The least increase of sthenic diathesis now brings on a disturbance of the functions, or actual disease; the commencement of which is generally a shivering, and a sense of cold; thirst and heat succeed; and then generally a pain in some part, either external or internal: costiveness generally attends this state, the urine is clear, and secreted in small quantity; memory and imagination become diminished, and there is generally less appetite for food. In peripneumony, inflammatory sore throat, and acute rheumatism, there is an inflamed condition of the lungs, of the parts about the throat, or of the muscles of the extremities: this shows that the excitement here is greater than in other parts of the body; but it is still increased or too great in every part, only those parts which give the peculiar character to the disease are more affected than other parts of the body, by being more exposed to the exciting causes: thus, if a person be in perfect health, or a little below, he will not be easily affected by any of the exciting causes of sthenic disease, unless their application be very violent; he will go into a warm room out of the cold air, and feel no other effect than a pleasant glow: but if, by high living, or other means, he is brought near the point of predisposition to sthenic disease, then the slightest additional stimulus will bring it on, and if the throat has been exposed to the application of cold, and the person comes afterwards into a heated room, an inflammation of the parts about the throat, or an inflammatory sore throat, accompanied by a sthenic diathesis of the whole system, will be the consequence. This cannot be cured by merely diminishing the excitement of the part, while the excitement of the whole system remains: if we apply leeches to the throat in this state, to diminish the quantity of blood, we only debilitate the vessels, while fresh quantities of blood are poured into them from the too full vessels of the body; even if we could thus remove the sthenic diathesis of the part, we should go but a little way towards removing the inflammatory disease, which universally pervades the system. The mode to be pursued therefore is, to take a quantity of blood from the body, by opening a vein; to keep the body cool, by remaining in a room where the temperature is at temperate, or a little below; by abstaining from animal food, and from spirituous or fermented liquors; and by the exhibition of purgatives, or at least of laxatives. Then leeches or blisters applied to the part affected will produce a good effect; and even stimulant applications to the inflamed part may be advantageous; for a topical inflammation, as we shall afterwards have occasion to see, depends on a debilitated state of the minute vessels of the part, while at the same time the action of the whole system is increased. Besides the energy of the exciting hurtful powers, which I have mentioned, there is in the parts which undergo the inflammation, a greater sensibility, or an accumulated excitability; by which it happens that some are more affected than the rest. To this we may add, that whatsoever part may have been injured by inflammation, that part in every future sthenic attack is in more danger of being inflamed than the rest. Hence inflammatory sore throat, rheumatism, and some other complaints of the kind, when once they have supervened, are very apt to recur. Among the sthenic or inflammatory diseases may be enumerated rheumatism, catarrh, cynanche, or sore throat, scarlet fever, inflammations of the brain, stomach, lungs, &c. &c. Many of the contagious diseases, particularly small pox and measles, produce a sthenic state, and are to be cured, or their action moderated, by the debilitating plan which has been pointed out; and particularly by a moderate, constant, and equable diminution of temperature. Hence the violence of these diseases is greater when they attack a person already predisposed to sthenic diathesis, but much more mild when the excitement is rather under par. LECTURE XII. ON INFLAMMATION AND ASTHENIC DISEASES. The last lecture was taken up chiefly with an account of sthenic diseases, or those depending on too great a degree of excitement, and which have been generally, but improperly, called inflammatory or phlogistic. In that lecture I attempted to show, that when the natural exciting powers, which support life, act with too much power, or particularly if we employ any stimulants not natural to the body, the functions both of body and mind become increased in vigour; but if the exciting causes are continued and increased, the functions become disturbed, and their action becomes painful and distressing. This state, which is called sthenic diathesis, is often accompanied by a redness, swelling, pain, and increased heat of some particular part: these symptoms constitute what is usually termed an inflammation of the part. The method of cure in sthenic diseases was shown to be, by reducing or moderating the action of the exciting powers; by keeping the body cool; abstaining from high seasoned, and, in general, from animal food; by the use of purgatives, and in many cases by diminishing the quantity of blood in the body. I mentioned likewise, that it would be but of little use to attempt to subdue the excitement of the inflamed part, unless the excitement of the whole system was previously diminished; but that after a general bloodletting, stimulant remedies applied to the inflamed part, might be employed with success. This is strictly agreeable to experience, but at first sight seems so very contrary to the principles that have been advanced, that I shall endeavour to explain the phenomena of inflammation, which do not seem to be in general well understood. All kinds of inflammation agree, in being attended with redness, increased temperature, pain, and swelling; but they vary according to the situation and texture of the part affected. All parts of the body, excepting the cuticle, nails, hardest part of the teeth, and hair, are subject to inflammation. Among the causes of these complaints, may be enumerated too full a diet, particularly too free a use of fermented liquors, and whatever increases the impetus of the blood towards the part, as mechanical and chemical irritation, and sudden changes of temperature, particularly from cold to heat. To explain the nature of inflammation, it may be observed, that such is the wise constitution of the animal body, that whatever injures it, excites motions calculated to correct or expel the offending cause. Thus if an irritating substance is received into the stomach, it excites vomiting; if into the lungs, a violent fit of coughing is excited, and if into the nostrils, sneezing is the consequence. In such cases we can readily trace the motions excited, and the manner in which they act; but cannot trace the manner in which the offending cause excites these motions. Now if it can be shown that inflammation, like vomiting and coughing, is an effort of the system to remove an offending cause, and if we can trace every step of this operation, with the exception of the changes induced on the nervous system, we shall understand the nature of inflammation as completely as that of any function of the body. The circumstance the most difficult to explain, is the increased redness of the part affected, which can only depend on an increased quantity of blood in the vessels. This has been supposed to depend upon an increased action of the vessels of the part; but that this is not the case, must be evident from what was said when we were speaking of the circulation of the blood. It was shown, that the circulation could not be carried on by the mere force of elasticity alone; this force, were it perfect, would produce no effect; but as there is no body with which we are acquainted that is perfectly elastic; so the coats of the arteries are very far from being so, hence their effect as elastic tubes will be to diminish the force of the heart, instead of adding to it; for a certain quantity of this force will be spent in distending the vessels, which, were they perfectly elastic, would be restored to them, but as this is not the case, this force is by no means restored. Indeed a variety of considerations, observations, and experiments, tend to prove, that the vessels are endowed with a power very different from elasticity, which differs only in degree from that of the heart; in short, they are possessed of muscular power. After each contraction of the muscular coat, the elastic will act as its antagonist, and enlarge the diameter, till the vessel arrive at a mean degree of dilatation, but after this there is no further power of distention inherent in the vessel. The action of the elastic coat ceases; and no one will assert that a muscular fibre has power to distend itself. The only power by which the vessel can be further distended, is the vis a tergo: after the vessel arrives at its mean degree of dilatation, both the elastic and muscular coats act as antagonists to the vis a tergo, or force which propels the blood into, and thus tends further to dilate the vessel. If then the vis a tergo become greater than in health, the powers of resistance inherent in the vessels remaining the same; or if the latter be weakened, the vis a tergo, or propelling force, remaining the same, the vessel must suffer a morbid degree of dilatation. These appear to be the only circumstances under which a vessel can suffer such dilatation. But if, while the powers of the vessels remain the same, the vis a tergo, or propelling force, be diminished, or the propelling force remaining the same, the power of the vessels become increased; then an opposite condition or state of the vessels, viz. a preternatural diminution of their area, will take place. In the one case the distending force bears too great a proportion to the resisting force; and preternatural distention is the consequence. In the other the resisting force bears too great a proportion to the distending force, and preternatural contraction is the consequence. It is not necessary that the vessels should be in a state of greater debility than in health, in order that an inflammation or distention may take place: it is only necessary that the proportion which their action bears to the propelling force be less than in health. If the propelling force remain the same, the vessels must be in a state of debility before an inflammation can take place; but if the propelling force be increased by a fullness of the vessels and sthenic diathesis, inflammation may take place, although the vessels of the part act as powerfully as in health, or more so. But after inflammation has taken place, as the vessels are preternaturally distended, they must also be debilitated. The degree of inflammation is not however proportioned to the debility of the minute vessels of an inflamed part, but to the diminished proportion of their power to the propelling force. When, therefore, inflammation arises from an increased action of the arterial system, or an increased propelling force, while the force of the capillaries or minute vessels remains the same, it constitutes what is called an active inflammation, and is to be cured by general bleedings, and then by gentle applications of tonics to the part, to increase its action; but when it arises from a debility of the minute vessels, without any increase of the propelling force, it forms what is known by the name of passive inflammation; in which general bleeding is not required, but the application of stimulants and tonics to the inflamed part to enable the vessels to recover their lost tone, and restore the balance between their action and the vis a tergo. From what has been said, it must be evident, that if inflammation depend on the diminished proportion of the power of the capillaries to the propelling force, it will be more apt to supervene under the three following circumstances. 1. In a state of plethora, because then all the vessels are over distended, and consequently any cause tending further to distend them, whether it be a cause which debilitates them, or increases the propelling force, will be more felt than in health. 2. In a state of general debility, because the vital powers in any part are more readily destroyed than in health. 3. In a state of general excitement, because then the propelling force is every where strong, and consequently apt to occasion distention of the vessels, wherever any degree of debility occurs. These are the states of the system which are found to predispose to inflammation. In the first and last, the inflammation is generally of that kind, which is termed active: the propelling force is considerable, and the larger arteries are readily excited to increased action. In the second state the inflammation is of the passive kind. This is not merely a useless physiological disquisition; it is of the greatest use in directing our practice; and teaches us that, in passive inflammation, which has all the symptoms of active, and therefore shows in a striking point of view the fallacy of symptoms, we shall not succeed by applying leeches, and other debilitating means, to the inflamed part; on the contrary, we shall aggravate the complaint; and the cure must be effected by stimulants applied to the part. As an instance of this kind of inflammation, I may mention that kind of ophthalmia or inflammation of the eyes, which is of long standing, and which not only resists the powers of leeches and blisters, but is increased by them. I have frequently been consulted by patients, who had for months been under the debilitating plan, without any benefit; and who have been relieved almost instantly by the application of electricity and a stimulating lotion, which restored the tone of the debilitated vessels of the sclerotic coat, and enabled them to expel their overcharged contents; and the balance between their action and the propelling force being restored, the inflammation disappeared. Indeed the effects of electricity in these kinds of inflammations are wonderful: it seems to act almost by a charm, so quickly does the inflammation subside; but when we understand the nature of this kind of inflammation, it is nothing but what we might expect from its action. I have been thus minute on the subject of inflammation, because the theory of it, which I have attempted to defend, differs considerably from the commonly received opinions. I shall now proceed to consider the nature of asthenic diseases. From what has been already said, it must be evident that the causes of diseases which we have assigned, are very different from those delivered by physicians who preceded Dr. Brown. Some physicians imagined that diseases were caused by a change in the qualities of the fluids, which became sometimes acid, and sometimes alkaline; or on a change of figure of the particles of the blood: some imagined diseases to be owing to a rational principle, which they called the vis medicatrix naturae, which governed the actions of the body, and excited fever or commotion in the system to remove any hurtful cause, or expel any morbid matter, which might have insinuated itself into the body. Others supposed many diseases to arise from a constriction of the extreme vessels by cold; or from a spasm of them, which was a contrivance of the vis medicatrix, to rouse the action of the heart and arteries to remove the debility induced. We have seen, however, that health and diseases are the same state, and depending upon the same cause; viz. excitement, but differing in degree; and that the powers producing both are the same, sometimes acting with a proper degree of force: at other times either with too much, or too little. We shall now examine how the diminished actions of the different exciting powers produce asthenic disease; and we shall take them in the same order as when we were speaking of sthenic diseases. It must be recollected however that an asthenic state, or a state of debility, may be produced in two ways. First, by directly diminishing the action of the exciting powers. Secondly, by exhausting the excitability, by a strong or long continued stimulant action. The former state is called direct debility, and the latter indirect debility. This is not merely a distinction without a difference, the body is in very different states, under these two different forms of disease. In the former case, the excitability is abundant, and highly susceptible of the action of stimulants. In the latter, it is exhausted, and the body has very little susceptibility. Cold, or a diminution of heat, carried beyond a certain degree, is unfriendly to all animals. Dr. Beddoes has shown very clearly in his Hygeia, that it is the cause of a great many diseases which take place at boarding schools, and that it there gives origin to a great number of diseases that afterwards arise, and, indeed, not unfrequently ruins the constitution. It produces relaxation of the vessels, asthenic or passive inflammation, and even gangrene. He has shown that in most schools children are afflicted with chilblains from this cause; this is a case of passive inflammation, but is only a symptom of the general debility induced, which shows itself afterwards by the production of other symptoms. Hence it is necessary for the preservation of health, that the temperature of school rooms should always be kept equable, and regulated by means of a thermometer. It should not exceed 50 degrees, nor should it be allowed to fall much below it. If precautions of this kind are thought to be necessary, and practised with uncommon attention, in places where vegetables are reared, surely they ought not to be neglected in those seminaries where the human species are to be brought to maturity, and a good constitution established. But though I have no doubt whatever, that this equable temperature would prevent a number of diseases, which originate in too low a temperature, yet I am far from wishing to have it thought that I would not induce a hardy state of the constitution, which would enable it to bear the vicissitudes to which it must be exposed in its journey through life, by every means in my power. Hardiness is the most enviable of all the attributes of animal nature, and can neither be acquired, nor recovered when it is lost, but upon certain terms, to which many people submit with reluctance, because they must give up many indulgences and gratifications with which it is utterly inconsistent. One of the causes that chiefly contributes to reduce persons living in affluence below the standard of hardiness, is the dependence they place on a considerable degree of external warmth, for preserving a comfortable state of sensation. From what has been said again and again in some of the latest of these lectures, it must be evident that continued warmth renders the living system less capable of being excited to strong, healthy, and pleasant action: heat in excess, whether it may be excess of duration or intensity, constantly debilitates, by exhausting the excitability of the system, and thus producing a state of indirect debility. Every muscle steeped in a heated medium, whether of air or water, loses much of its contractibility. A heart kept in heated air, or put in hot water, will not contract on the application of a stimulus; even the limb of a frog, when heated in this manner, ceases to move on the application of the galvanic exciters. Every nerve grows languid, and when it does become excited, it acquires a disposition to throw the moving fibres, with which it is connected, into starts, twitchings, and other irregular convulsive motions. Though therefore nothing can more contribute to the health of the body than a moderate and well regulated temperature, about 48 or 50 degrees, sometimes for a short interval a little lower, when exercise is taken at the same time, yet when we consider the life led by persons of fashion, we should hope that it proceeded from ignorance of these consequences; so diametrically opposite is it to the dictates of nature and reason. Instead of rising from table after dinner, and availing themselves of the cooling and refreshing qualities of the air, even in the finest seasons, when every thing which pure and simple nature can offer, invites them abroad, they do every thing they can, as Dr. Beddoes observes, to add to the overstimulating operation of a full and hearty dinner. After taking strong wine with their food, they sit in rooms rendered progressively warmer, all the afternoon, by the presence of company, by the increase of fires, and for more than half the year, by the early closing of the shutters, and letting down of the window curtains. After a short interval, tea and coffee succeed; liquors stimulating both by their inherent qualities, and by virtue of the temperature at which they are often drank. And that nothing may be wanting to their pernicious effect, they are frequently taken in the very stew and squeeze of a fashionable mob. The season of sleep succeeds, and to crown the adventures of the evening, the bed room is fastened close, and made stifling by a fire: and though the robust may not quickly feel the effects of this mode of life, with the feeble it is quite otherwise. These, as they usually manage, rarely pass a few hours of sleep without feverishness and uneasy dreams; both of which contribute to their finding themselves by far more spent and spiritless in the morning, than after their evening fit of forced excitement, instead of having their spirits and strength recruited by the "chief nourisher in life's feast," Perhaps they drink tea before rising, and indulge in a morning nap; this weakens much more than the greatest muscular exertion they would be capable of supporting for an equal time. For the sleep at this time is almost invariably disturbed, and attended by a heat of the skin. The reason of this must be evident to every one who has attended these lectures. The effect of sleep is to accumulate the excitability, or render it more sensible to the effects of any stimulants applied. This takes place in every constitution, and much more in the more delicate: hence the heat of the bed, and of the tea, acts so powerfully on the surface, as, in general, to produce great perspiration, or, at any rate, great languor and debility. Let me ask, can any one, who lives in this manner, expect to enjoy good health? With as great probability might we expect, that when we plunged a thermometer into hot water, the mercury would not rise, or when we applied a lighted match to gunpowder, it would not explode. The laws of nature are constant and uniform, and the same, or similar causes, both in the animate and inanimate world, are always productive of the same, or similar effects. The cure of these complaints is at least obvious, if not easy. It consists in deserting crowded and heated rooms, at least for part of the time they have been usually occupied; in abstaining from strong wines; in keeping the bed rooms moderately cool; and retiring to rest at a proper hour. With respect to the effects of nutriment, in producing asthenic diseases, we may observe, that all watery vegetable food, too sparing a use of animal food, as also meat which is too salt, and deprived of its nutritious juices by keeping, when more nutritious matter is at the same time withheld, constantly weaken, and thereby tend to produce asthenic diseases. Hence would appear to arise that remarkable imbecility of body and mind which distinguishes the Gentoos. Hence arise the diseases with which the poor are every where afflicted; hence scrofula, epilepsy, and the whole band of asthenic diseases. But intemperance in eating and drinking, or taking nutritious and highly stimulant substances too freely, will, infallibly, bring on asthenic disease, or a state of indirect debility, by exhausting the excitability; and it must be observed, that this species of debility is much worse to cure than the direct kind; for in the latter we have abundance of excitability, and a variety of stimuli, by which we can exhaust it to the proper degree, and thus bring about the healthy state; whereas, in indirect debility, the vital principle or excitability is deficient; and we have not the means of reproducing it, at pleasure, absolutely under our command. Besides, the subtraction of stimulants, which is one of the most certain means we have of accumulating excitability, if carried to a great extent, in diseases of indirect debility, would produce death, before the system had power to reproduce the lost or exhausted excitability. Hence the cure, in these two kinds of debility, must be very different: in cases of direct debility, as in epilepsy, we must begin with gentle stimulants, and increase them with the greatest caution, till the healthy state is established: we must, however, guard most carefully against over doing it; for, if we should once overstep the bounds of excitement, and convert the direct into indirect debility, we shall have a disease to combat, in which we have both a want of excitement and of exciting power. In cases of violent indirect debility, as, for instance, in gout, when it affects the stomach: it would be wrong to withdraw the stimulus, for the excitability is in such an exhausted state as to produce no action, or very imperfect and diseased, from the effect of the common exciting powers; we must, therefore, here apply a stimulus greater than natural, to bring on a vigorous and healthy action, and this stimulus we should gradually diminish, in order to allow the excitability to accumulate, by which the healthy state will be gradually restored. This method was very judiciously recommended, by a very eminent physician, in the case of a Highland chieftain, who had brought on dreadful symptoms of indigestion by the use of whisky, of which he drank a large silver cup full five or six times in the day. The doctor did not merely say, diminish the quantity of spirits gradually, for that simple advice would not have been followed; but he advised him to drink the cup the same number of times full, but each morning to melt into it as much wax as would receive the impression of the family seal. This direction, which had something magical in it in the mind of the chieftain, was punctually obeyed. In a few months the cup was filled with wax, and would hold no more spirits; but it had thus been gradually diminished, and the patient was cured. This reminds me of a number of cases, which had been brought on by drinking porter, and other stimulant liquors, without knowing the taste of water. In many of these cases if a moderate quantity of water were drank every day they would be cured; but you would find few who would follow such plain and simple directions. How then must a physician proceed? Why, as is generally done by the most judicious: they direct their patients to Bath or Buxton, and there advise them to swallow a certain quantity of water every day, which they do most scrupulously, and, of course, return home cured. As causes of asthenic disease, we must not omit the undue exercise of the intellectual functions. Thinking is a powerful exciting cause, and produces effects similar to those of intoxication. None of the exciting powers have more influence upon our activity, than the exercise of the intellectual powers, as well as passion and emotion. Homer, the great observer and copyist of nature, observes of the hero, whom he gives for a pattern of eloquence, that, upon his first address, before he had got into his train of thought, he was awkward in every motion, and in his whole attitude; he looked down upon the ground, and his hands hung straight along his sides, as if they had lost the power of motion; and his whole appearance was a picture of torpidity. But when he had once fairly entered upon his subject, his eyes were all on fire, his limbs all motion, grace, and energy. Hence, as the exercise of the intellectual functions evidently stimulates, an excess of thinking must bring on indirect debility, by exhausting the excitability. But though we do meet with instances of indirect debility arising from this source, it must be confessed that they much oftener arise from the use of very different stimulants. As excessive exercise of the intellectual powers will bring on indirect debility, so the deficient, weak, or vacant state of mind, which is unable to carry on a train of thinking, will produce direct debility. Indeed this debility often occurs to those whose minds have been all their life actively engaged in business, but who have at last retired to enjoy themselves, without having a cultivated mind fit for retirement. They become languid, inert, and low spirited, for want of the stimulus of mental exertion; and in many cases cannot be completely restored to health, till they are again engaged in their usual occupations. Violent passions of the mind, such as great anger, keen grief, or immoderate joy, often go to such an extent as to exhaust the excitability, and bring on diseases of indirect debility. Hence both epilepsy and apoplexy have been the consequences of violent passion. On the contrary, when there is a deficiency of exciting passion, as in melancholy, fear, despair, &c. which are only lower degrees or diminutions of joy, assurance, and hope, in the same way that cold is a diminution of heat, this produces a state of direct debility. The immediate consequences observable are, loss of appetite, loathing of food, sickness of the stomach, vomiting, pain of the stomach, colic, and even low fevers. The effect of impure air, or air containing too small a proportion of oxygen, is likewise a very powerful cause of debility. In short, when any or several of these causes, which have been mentioned, act upon the body, asthenic diseases are the consequence. Asthenic diseases, as has frequently been hinted, may be divided into two classes, those of direct debility, and those of indirect debility. Among the diseases of direct debility may be enumerated dyspepsia, hypochondriasis, hysteric complaints, epilepsy, bleeding of the nose, spitting and other effusions of blood, cholera morbus, chorea, rickets, scrofula, scurvy, diabetes, dropsy, worms, diarrhoea, asthma, cramp, intermittent fevers. Among those of indirect debility, or which are produced by over stimulating, which exhausts the excitability, may be enumerated, gout, apoplexy, palsy, jaundice, and chronic inflammation of the liver, violent indigestion, confluent small pox, typhous fever, and probably the plague, dysentery, putrid sore throat, tetanus. Diseases, therefore, according to this system, may be divided into two classes. First, general diseases, which commence with an affection of the whole system, and which must be accounted general, though some part may be more affected than the rest. Secondly, local diseases, which originate in a part, and which are to be regarded as local, though they may sometimes in their progress affect the whole system, like universal diseases: still however they are to be cured by remedies, applied not to the whole system, but to the part affected only. A pleurisy or peripneumony, for instance, is a general disease, though the chief seat of the symptoms seems confined to a portion of the thorax: but the affection of this part, though it may be somewhat greater than that of any other equal part, is vastly less than the affection or diathesis diffused over the whole body. The exciting or hurtful causes which produce these diseases, by no means exert their whole power upon a small portion of the superficial vessels of the lungs, and leave the rest untouched; on the contrary, they affect exery part of the system, and the whole body partakes of the morbid change. Indeed the general or universal affection; viz. a sense of heaviness and fullness, uneasy sleep, and other symptoms of increased excitement, are commonly perceived some time before the pain of the thorax becomes sensible. The remedies which remove the disease; viz. venesection, abstaining from animal food, and every mode of debilitating, do not exert their whole efficacy on an inflamed portion of the lungs; for by removing the affection of the lungs we should go but a little way towards removing the disease. Among local diseases we may enumerate wounds, or solutions of the continuity of the part, bruises, fractures, inflammations from local irritation, &c. Hence it is evident that the treatment of general diseases is the province of the physician; and of local ones of the surgeon. But there are some general diseases which are apt to degenerate into local, and therefore require the attention both of the physician and the surgeon. Among these we may reckon suppuration and gangrene, sphacelus, and some others. The first class, or general diseases, may be divided into two orders; sthenic, and asthenic. The asthenic order may be subdivided into two genera; viz. diseases of direct debility, and diseases of indirect debility; for debility, according to the system I am explaining, is that relaxed or atonic state of the system which accompanies a deficient action of the stimulant or exciting powers; and this deficient action may arise immediately from the partial or too sparing application of the exciting powers; the excitability or capacity of the system to receive their actions, being unaffected or sufficiently abundant; or it may arise from the excitability being exhausted, by the violent or long continued action of the exciting powers. This arrangement of diseases, which naturally follows from the fundamental principles of the doctrine, and which is guided by the state and degree of excitement, is widely different from that of former nosologists, who have arranged or classed them according to symptoms, which have already been shown to be fallacious; and which method of arrangement brings together diseases the most opposite in their nature, and separates those most nearly allied. This is evident in every part of the nosology of Sauvages and Cullen. In the genus cynanche of the latter, are placed the common sthenic or inflammatory sore throat, or cynanche tonsillaris, and the putrid or gangrenous sore throat, the cynanche maligna: the former is a sthenic disease; the latter one of the greatest debility; yet they have the same generic name. The mode of classing diseases which I have adopted, after the example of Dr. Brown, is the consequence of first taking a view of the nature of life, and the manner in which it is supported; and from thence observing how those variations from the healthy state, called diseases, are produced; and this is certainly the proper plan; for, as every effect will be produced with more accuracy, whilst its cause is acting in a proper degree, it is certainly right to begin by drawing our general propositions from the healthy state; by which means we avoid being misled by those false appearances which the living system puts on, during a morbid state; and though the contrary has been the general practice of nosologists and pathologists, I must confess it appears to me like beginning where the end should be; for to lay down rules for restoring health, and begin by observing the phenomena of disease, is like building a house, and beginning with the roof. In the last lecture I pointed out the general method of curing sthenic diseases; I shall now proceed to the cure of asthenic, and shall begin with those depending on direct debility, as in these diseases the excitability is morbidly accumulated, and consequently more liable to be overpowered by the action of a stimulus, we must, therefore, at first, apply very gentle stimulants, increasing them by degrees, till the excitement be arrived at the healthy state. In cases of indirect debility, the excitability is so far exhausted as not to be sufficiently acted on by the ordinary powers which support life; we must therefore employ, at first, pretty strong stimulants, to keep up such a degree of action as is necessary to preserve life; we should, however, be careful not to overdo it; for our intention here, in giving these stimuli, is only to keep up life, while the cure must depend upon the accumulation of the excitability. That this may take place, therefore, we must gradually lessen the quantity of stimulus, till the excitability become capable of being sufficiently acted on by the exciting powers, when the cure will be affected. There is, however, an important point, with respect to the cure of diseases of exhausted excitability, which could not be known to Dr. Brown; and this depends on the fact which was formerly pointed out; viz. that the degree of excitability was in proportion to the oxydation of the system. On this account I have given the oxygenated muriate of potash in typhus, which is a disease of diminished excitability, in more than one hundred cases, without the loss of one, a success which has attended no other mode of practice in this disease, if we except, perhaps, the affusion of cold water, as described by Dr. Currie, the effects of which are wonderful, but which can only be applied at the commencement of the disease. In all diseases of indirect debility, therefore, it is proper to attempt the introduction of oxygen into the system, by the oxygenated muriate of potash, acid fruits, nitre, &c. I do not think that the inhaling of oxygen gas for a few minutes in the day can do much good; but free ventilation of apartments, and gentle exercise in the open air, are highly useful. In either case of debility, we should by no means rely on the action of medicines alone; for though there are a variety of stimulants which will produce excitement, yet this is only temporary, we must therefore endeavour, by nutritious substances, to fill the vessels with blood, and employ all the natural exciting powers in due proportion as soon as possible. But in the cure of either sthenic or asthenic diseases we shall seldom succeed by the use of one remedy only: for since no stimulus exerts its effects equally on all parts of the body, but always acts more powerfully on some part than on others, we cannot by the use of one remedy alone obtain an equal increase or diminution of excitement. There are few diseases however in which the excitement is equally increased or diminished over the body; some part being generally more affected than the rest; and this inequality produces the various phenomena or forms of disease; indeed no disease but increase or diminution of strength would take place, on the supposition that an equal increase or diminution of excitement all over the body, were produced by the hurtful powers causing the disease. From what has been said, it necessarily follows, that every stimulus will not be equally efficacious in curing every form of disease; which is sufficiently confirmed by experience. Hence there may be some ground for the appellation of specifics, as some medicines may act more powerfully upon the part which is the principal seat of the disease, than others do. In the cure of diseases we ought always to attend to two things most carefully: first, to employ the proper kinds of powers, and then not to overdo them, so as to convert either diathesis into the other; and by passing over the line of health, instead of the intended cure, to substitute one disease instead of another, and thereby bring life itself into danger. LECTURE XIII. ON THE GOUT. There is no disease, with which the human race is afflicted, whose nature has been more mistaken than that which is to form the subject of our present consideration. It has been regarded by most practitioners as a salutary effort of the body to expel some hurtful cause, and restore health; and therefore has been looked upon as desirable to the patient. To attempt to cure it, therefore, would have been wrong, had it been curable; but it has likewise been looked upon as beyond the reach of medicine, or perfectly incurable; and, on both these accounts, after having tried a variety of drugs, without any good effect, the physicians have at last abandoned their patients, to the care of patience and flannel, which, if the constitution be not very much shattered, will often see them through the disease. But that it is a salutary disease I deny; and I affirm, that it restores health in no other way, than the indigestion of a habitual dram drinker would be relieved by a disease in the throat, which would, for a time, prevent his swallowing any more liquor; the consequence would be, that his digestive powers would recover their tone, and he would, after a few weeks, feel himself better. In the same way the pain and fever, which attend gout, and at the same time the inability to move, with the weakened stomach, and bad appetite, prevent the continuance of the mode of life which brought on the disease; and thus, a truce being obtained, the exhausted excitability of the body is allowed to accumulate, and the constitution, of course, feels itself renovated. Were the disease to be viewed in this light, it is probable that many patients might in future desist from their former mode of life, which brought on the disease; and we might venture to promise them, if they did, that they would have no return of the complaint. But the misfortune is, they think the gout has restored their constitution, and that therefore they may return to their old mode of living with impunity; in consequence of which, after a few months more, the excitability is again exhausted; symptoms of indigestion come on, and the stimulant mode of living is increased, with a view to bring on the disease, which is to cure these symptoms. In this way, each time, a greater and greater degree of indirect debility is induced, and at last the system becomes so enfeebled, that the asthenic inflammation is not confined to the extremities, but attacks the head, the stomach, the lungs, and often puts a period to the existence of the patient, which has for some time been miserable. Besides, the idea, that the gout is incurable, is a false, and a very dangerous doctrine; this is very far from being the case, and I am firmly persuaded, not only from the nature of the disease, but from experience, that it may always be cured, if taken in time, and proper directions be followed. If, by the cure of gout be meant the administration of some pill, some powder, or some potion, which shall drive away the complaint, I firmly believe, that it never was, nor ever will be cured. Indeed, it is astonishing that such an idea should have ever entered the mind of any person, who has any knowledge of nature, or particularly of the human frame; for, if the gout is a disease of indirect debility, and the effect of intemperance, as will be shown by and by, then a medicine to cure it must be something to enable a man to bear the daily effects of intemperance, during his future life, unhurt by the gout, or any other disease; that is, it must be something given now, that will take away the effects of a future cause; as well might a medicine be given to prevent a man breaking his leg, or his arm, seven years hence. But no rational physician, or surgeon, would give a medicine with this view, in such a case as I have supposed; on the contrary, he would caution his patient against mounting precipices, scaling walls, or bringing himself again into a situation, such as produced the accident; and if he took his advice, he would, in all probability, escape a broken limb in future. In the same way a rational physician would advise a person recovering from gout, to abstain totally and entirely from the course of life which brought it on; and this being complied with, we might venture to predict, with as much certainty in the one case as in the other, that he would in future escape it. What I have frequently endeavoured to inculcate in the course of these lectures, always appears to me of the utmost importance: I mean, the general diffusion of physiological knowledge, or a knowledge of the human frame; this knowledge ought to form a part of general education, and is, in my opinion, as necessary for a person to learn as writing, or accounts, or any other branch of education; for if it is necessary that a young man should learn these, that he may be able to take care of his affairs, it surely can be no less necessary, that he should learn to take care of his health; for to enjoy good health, as a celebrated practical philosopher observes, is better than to command the world. If knowledge of this kind were generally diffused, people would cease to imagine that the human constitution was so badly contrived, that a state of general health could be overset by every trifle; for instance, by a little cold; or that the recovery of it lay concealed in a few drops, or a pill. Did they better understand the nature of chronic diseases, and the causes which produce them, they could not be so unreasonable as to think, that they might live as they chose with impunity; or did they know any thing of medicine, they would soon be convinced, that though fits of pain have been relieved, and sickness cured, for a time, the reestablishment of health depends on very different powers and principles. Those who are acquainted with the nature and functions of the living body, well know, that health is not to be established by drugs; but that if it can be restored, it must be by nicely adjusting the action of the exciting powers to the state of the constitution, and the excitability; and thus gently and gradually calling forth the powers of the body to act for themselves. And though I believe that most general diseases will admit of a cure, yet I am confident, that no invalid was ever made a healthy man by the mere power of drugs. If this is a truth, should it not be universally known? If it were, there would undoubtedly be an end of quackery, for all quack medicines, from the balm of Gilead, to the botanical syrup, are supposed to cure diseases, or at least asserted to do so, in this mysterious manner. Dr. Cullen, in his Nosology, gives us the following definition of the gout. "Morbus haereditarius, oriens sine causa externa evidente; sed praeeunte plerumque ventriculi affectione insolita; pyrexia; dolor ad articulum, et plerumque pedis pollici, certe pedum et manuum juncturis, potissimum infestus; per intervalla revertens, et saepe cum ventriculi et internarum partium affectionibus alternans." Now, though this definition comprises a tolerably good general character of the disease, it contains some notions, depending on the prejudice of hypothesis, which, on a careful examination, ought not, I think, to be admitted. In the first place, I would deny, that the gout, considered as a diseased state of the system, is hereditary. This may perhaps excite some degree of surprise; and, "I had it from my father," is in the mouth of a great majority of gouty patients. If the diseased state of the system, which occurs in gout, were hereditary, it would necessarily be transmitted from father to son; and no man, whose father had it, could possibly be free from it. There are, however, many instances to the contrary. Our parents undoubtedly give us constitutions similar to their own, and there is no doubt, that if we live in the same manner in which they did, we shall have the same diseases. This, however, by no means proves the disease to be hereditary. We shall hereafter see, that the gout is a disease of indirect debility, brought on by a long continued use of high seasoned food and fermented liquors. There is no doubt that particular constitutions are more liable to be affected by this mode of living than others; and if my father's constitution be such, I, who probably resemble him in constitution, shall in all probability be like him, subject to the gout, provided I live in the same way; this however by no means proves the disease to be hereditary. The sons of the rich, indeed, who succeed to their fathers estate, generally succeed also to his gout, while those who are excluded from the former, are also exempted from the latter, and for very obvious reasons, unless they acquire it by their own merit. So that though the son of a gouty parent may have a constitution predisposing to the gout; that is, more liable to be affected by causes, which produce this disease, still, if he regulate the stimuli to the state of his excitability, he will remain exempt from it. This distinction is of much greater importance than is generally imagined; for if a person firmly believes that the gout, as a disease, is hereditary, what will be his conduct? My father had the gout, says he, therefore I must have it; well, what cannot be avoided, must be endured; let me then enjoy a short life, but a merry one: he therefore abandons himself to a luxurious mode of life, and, if the gout be the consequence, which most probably it will, he accuses his stars, and his ancestors, instead of his own misconduct. On the contrary, if a person be convinced that he has received from his ancestors a constitution liable to be overpowered by the use of high seasoned food, and fermented liquors, and excited into gouty action, what will be his conduct? Surely, if he reason at all, it must be in this way: my father was dreadfully afflicted with the gout; I have frequently witnessed his sufferings with the deepest concern. But is not my constitution, which resembles his, liable to be affected in the same manner, by similar causes? To avoid his sufferings, therefore, I must be very temperate; more so than those who have not the hereditary propensity; for the exciting powers, which would only keep them in health, would, if applied to me, infallibly bring on the gout. In consequence of this reasoning, he adopts a temperate mode of living, and avoids the disease. From this you must be convinced, that it is not a matter of small moment to determine, whether the gout is hereditary, and consequently unavoidable, or not. The next part of Dr. Cullen's definition is "oriens sine causa evidente". This too, I can have little hesitation to pronounce erroneous. The cause of gout, namely, the use of highly seasoned food, and the use of fermented liquors, with, in general, a luxurious, and indolent mode of living, are quite evident enough in most gouty cases, and are amply sufficient to produce the disease. There is another part of the definition, likewise, to which I would object, as it gives a false idea of the nature of the disease, and therefore causes the preventative plan to be pursued with less confidence. I mean that part where he says "per intervalla revertens." That the gout, when once cured, is apt to return, if the mode of life which brought it on be not abandoned, no one will deny; nay, the fits will increase in violence, because the constitution gets more and more debilitated. This, however, is not peculiar to the gout, but common to most diseases. In describing a broken leg, it would surely be wrong to say, that it is a disease which returns at intervals, after being cured; yet, it will return as infallibly as the gout, if a person take the same kind of leap, or expose himself to the same accidents as those which brought it on. Let those, therefore, who wish to avoid a return of the gout, totally change their mode of living: otherwise, if the attacks return, let them blame themselves, and not the nature of the complaint. These observations were thought necessary, with a view to do away some prejudices, which very much retarded our inquiries into the nature and cure of this disease. I shall now proceed to give an account of the symptoms by which it is usually attended. The gout generally attacks the male sex; but it sometimes, though more rarely, attacks also the female, particularly those of robust and full habits. It does not generally make its appearance, till the period of greatest strength and vigour is past; for instance, about the fortieth year; but, in some cases, where the exciting causes have been powerfully applied, or where the hereditary predisposition is very strong, it attacks much earlier; such cases are, however, comparatively rare, and can, in general, be easily accounted for. This disease is seldom known to attack persons employed in constant bodily labour, and who live temperately; and is totally unknown to those who use no wine or other fermented liquors. If then a person of a full strong habit have for several years accustomed himself to full diet of animal food, and a regular use of wine, and malt liquor, though he may for a long time find that he can perform all the functions with vigour, his strength will at last fail: the mind and body become affected with a degree of torpor and languor for which he cannot account, and the functions of the stomach become more or less disturbed. The appetite becomes diminished, and flatulency, and other symptoms of indigestion are felt. These symptoms take place for several days, and sometimes for several weeks before the fit comes on; but often, on the day immediately preceding it, the appetite becomes greater than usual. In this state, if the person have fatigued himself by violent exercise, or if he have exposed the extremities to cold, or if his mind have been particularly affected by any anxiety, or distressing event; or in short, if any directly debilitating cause have been applied, the fit will often follow. It sometimes comes on in the evening, but more commonly, about two or three o'clock in the morning; the pain is felt in one foot, most commonly in the ball or first joint of the great toe; but sometimes in the instep, or other parts of the foot. With the coming on of this pain there is generally more or less of a cold shivering, which as the pain increases, gradually ceases, and is succeeded by heat, which often continues as long as the pain; from the first attack the pain becomes by degrees more violent, and continues in this state, with great restlessness of the whole body, till next midnight, after which it gradually remits, and after the disease has continued for twenty four hours from the commencement of the first attack, it often ceases, and with the coming on of a gentle perspiration allows the patient to fall asleep. The patient on coming out of this sleep in the morning finds the part affected with some degree of redness and swelling, which, after having continued for some days, gradually abate. Still however, after a fit has come on in this manner, although the violence of the pain after twenty four hours, by the excitement that it produces, cures itself, and is considerably abated, the patient is seldom entirely relieved from it. For several days he has every evening a return of considerable pain and fever, which continue with more or less violence till morning. This return is owing to the exhaustion of the excitability by the stimuli of the day, and its remission is caused by the accumulation of the excitability, by sleep. After having continued in this manner for several days, the disease often goes off, and generally leaves the person in much better health, and enjoying greater alacrity in the functions of both body and mind, than he had for some time experienced. This is owing to the general excitement produced by the pain, which removes the great torpor and debility which preceded the fit; and from the inability to take exercise or food, the excitability accumulates again. This is the true explanation: it does not depend on any morbid matter, which the gout hunts from its lurking places, drives to a joint, and thence out of the body, as has been imagined by many. At first the attacks of the disease are confined to one foot only: afterwards both feet become affected, though seldom at the same time; but when the inflammation appears in one, it generally disappears in the other, and as the disease continues to recur, it not only affects both feet at once, but is felt in the other joints, especially those in the upper and lower extremities, so that there is scarcely a joint in the body that is not on one occasion or other affected. After frequent attacks, the pains are commonly less violent than they were at first, the joints lose their strength and flexibility, and often become so stiff as to be deprived of all motion. Concretions of a chalky or calcarious nature are likewise formed upon the outside of the joints. This arises from an inability of the capillary vessels, which ought to secrete the calcarious matter, and deposite it in the bones, to perform their office, from debility: hence by sympathy other vessels ta ke up the matter and deposite it in the wrong place. These concretions, though at first fluid, become at last dry, and firm: they effervesce with acids, and are totally, or in a great measure, soluble in them. After this short description of the gout, when it occurs in its regular form, as it is called, I shall now proceed to inquire how the exciting causes produce this disease, and what is the state of the body under which it occurs. The gout seldom occurs but in those who have for several years lived upon a full diet of animal food, often highly seasoned, and at the same time been in the habit of taking daily, or at least very constantly, a greater or less quantity of fermented liquors, either in the form of wine, or malt liquor, or both. The affection of the limb has all the appearance of an active inflammation: the part becomes swelled, hot, red, and intolerably painful. It is this circumstance which has misled practitioners, who have supposed it a case of sthenic, or active inflammation: not only the appearance, but the causes which produced it, induced them to think so; hence they were naturally led to employ the debilitating plan: a little time and observation would, however, be sufficient to convince them of its inefficacy. They would find that the application of leeches to the part, and of the lancet to the arm, instead of subduing the inflammation, would increase it: or if it did not, that the pain often attacked some internal part, which was ascribed to a translation of the morbific matter from one part to another, but which is merely owing to an increased debility: a little attentive observation would convince practitioners, however mysterious it might seem to them, that this violent inflammation was not to be cured by debilitating: on the contrary, they would see cases, in which the patient, though contrarily to the strict orders of his physicians, could not forego his old habits; but would take his wine as usual, or in greater quantity, after a few days abstinence; and this abstinence having in some degree accumulated the excitability, he would find himself much relieved by wine, and would exultingly tell them, that they were mistaken. Circumstances of this kind seem to have staggered their faith a little, but still the idea of active inflammation which they believed was visible, and almost palpable, dwelt so upon their minds, that they were but half convinced. The favourite idea of increased action of the vessels of the part had so interwoven itself with every other, that we find it never lost sight of, in the indications of cure. Hence, though bleeding is not now generally practised with the lancet, yet leeches are often applied; but the most usual plan is to consign the patient to patience and flannel; strictly forbidding wine, or fermented liquors. As an exception to this general mode, it is however observed, by some practitioners, that when the stomach is weak, and when the patient has been much accustomed to the use of strong liquors, a little animal food, and even wine, may be allowable, and even necessary. Thus has an erroneous view of the disease been the cause of an inert practice, which wavers between the suggestions of a favourite hypothesis, and the conviction of facts. On inquiry, however, we shall find none of the increased vigour in the system, which has been suspected, nor increased action in the part more particularly affected; on the contrary, the whole body is in a state of indirect debility, or exhausted excitability, and the part more particularly affected, in a state of asthenic inflammation. If the gout were of a sthenic or inflammatory nature, might we not ask, why the causes which produce it, do not produce it in the meridian of life, when they produce their greatest effect, and when real sthenic diseases are most apt to occur? or, why the symptoms of the inflammation, like all other real sthenic inflammations, are not relieved by the debilitating plan? The contrary, however, points out to us clearly the nature of the disease: the gout is not a sthenic disease, or a disease of strength: it does not depend upon increased vigour of the constitution, and plethora, but is manifestly asthenic, like all the rest of the asthenic diseases. The mode of living is such as brings on indirect debility, or exhaustion of the excitability, such as the use of rich and highly seasoned food, and a daily use of fermented liquors. These at first certainly produce vigour, or strength, and will be the cause of sthenic diseases; but they are generally taken in such a manner, that, though they produce a degree of excitement above the point of health, still they only approach the line of sthenic disease, without in general falling into it. They continue, however, to exhaust the excitability, and by the time that the vigour of the body begins naturally to decline, the system of a person who has lived in this manner is unusually torpid; all the blood vessels, which have hitherto been distended with rich blood, begin to lose their tone, from their excitability having been exhausted by the use of these powerful stimulants; but this torpor is particularly and first experienced in those parts which have been more immediately subject to the action of the exciting causes; viz. the stomach and bowels: symptoms of indigestion occur, and the excitability of these organs having been almost entirely exhausted by the violent action of the stimulants applied, cannot now be roused to any healthy action; the food is not properly digested, but runs into a kind of fermentation, which causes an extrication of gas: this distends the stomach and bowels, and produces pains, uneasy eructations, and all the distressing symptoms of indigestion. Nor is this in the least surprising, when we consider that many people who have brought on complaints of this kind, have been in the habit of eating heartily of rich and highly seasoned animal food, and of drinking from a pint to a bottle of wine, and perhaps a quantity of malt liquor, almost every day of their lives for years. This mode is sufficient to wear out the powers of the stomach, were it three times as capacious as it is, and of the constitution, were it ten times as strong. When a torpor, or state of exhausted excitability, of the whole system, has been induced in this manner, and symptoms of indigestion produced, any directly debilitating cause applied to the extremities, adding to the indirect debility, causes a total torpor, or inactivity of the minute vessels of the part, and thus totally destroys the balance between the propelling and resisting force; hence the vessels will be morbidly distended with blood, a swelling and redness will take place, and an asthenic inflammation, produced in the way which I fully pointed out in the last lecture, will be established. Hence the pain, and other symptoms, which accompany a fit of the gout. Hence likewise we see, why debilitating powers applied to the part will not reduce the inflammation; and why a warmth, which aggravates every really sthenic inflammatory affection, is so comfortable in this. Almost any debilitating cause, when the system has been brought by intemperance to the torpid state, which I have described, will bring on a fit of the gout, but nothing more certainly than cold or moisture: hence if a person have his feet chilled or wet, he will be almost certain to have an attack. Hence we see that the asthenic inflammation is not the disease, but merely a symptom of it; and like other symptoms, fallacious in its appearance; the disease is a state of indirect debility, to which our attention ought to be directed. When this inflammation is violent, and accompanied with great pain, after several hours continuance, it excites the action of the minute vessels, enables them to propel the blood, by which they are morbidly distended, and restores the balance between the resisting and the propelling force; and thus the inflammatory appearances will for a time subside, but the torpor of the whole system remaining, and the debility of the vessels returning, when their excitement, which was the consequence of their action, has ceased, another asthenic inflammation will take place, which will again cure itself as before; so that during a paroxysm, several remissions will take place, as was mentioned in the description of the disease. As, during the paroxysm, the pain causes a considerable degree of excitement over the whole system, the action of the stomach and other parts is roused by it; during the fit likewise, little nutriment is taken, so that by the action of the stomach and bowels, they get rid of their load; rest likewise assists to accumulate the excitability, so that from all these causes together, the body becomes restored to a state of vigour, which, compared with its former torpidity, makes the patient imagine that this friendly disease has restored him to a state of unusual health, and even renovated the powers of his constitution. Under this mistaken idea, he does not, when the fit leaves him, abandon the mode of life, which brought on the disease; highly seasoned food, and the usual quantity of wine, are again resorted to: after a time the torpor of the system, and symptoms of indigestion return, and he again hopes that his friend the gout will come and cure him. By a continuance of this plan, the inflammation again appears; but the system having become more torpid, the inflammatory action is by no means so great as it was before: if it has power to restore the equilibrium between the resistance and propelling force, and thus cure itself, this effect is entirely confined to the inflamed part. The other foot labouring under similar torpor, or debility, now feels the effects of the propelling force, and an inflammation takes place in it, which having cured itself in the same manner, and the torpor of the foot first affected being returned, or even greater than it was before, on account of the previous excitement; the inflammation again attacks this foot, and thus the gout is supposed to emigrate from one limb to another. The gout, as a disease of general debility, however, remains the same; and it is only these symptoms, which form but a small part of the disease, that vary according to circumstances. If, during an asthenic inflammation of the lower, or upper extremities, the torpor and debility of the whole system increase, then the force of the circulation, or propelling force, being diminished, the symptoms of inflammation will suddenly disappear; but as great debility now prevails, the stomach will be apt to be affected with cramps or convulsions, or an asthenic inflammation of some internal part will take place: for, though the propelling force is not sufficient to overdistend the debilitated vessels of the extremities, it will distend those of the internal parts nearer the heart, which are now debilitated. In this case, it has been generally, but absurdly imagined, that the gout is translated, or recedes from the extremities to some internal part: the term of retrocedent gout has therefore been applied to occurrences of this nature. From the explanation which has been given, it is evident, that this term is improper. The general debility being increased, the propelling force becomes unable to produce an inflammation of the extremities, and this is the reason why it disappears. The disease, however, is not at all altered in its nature by this variation of symptoms. It is still the same, by whatever name it may be called. It sometimes happens, that after full living, the stomach becomes particularly affected, and the patient is troubled with flatulency, indigestion, loss of appetite, eructations, nausea, and vomiting, with great dejection of spirits, pain and giddiness of the head, disturbed recollection, or muddiness of intellect, as it is termed, with all the symptoms, which usually precede a regular fit of the gout, yet no inflammatory affection of the joints is produced. This state has been absurdly enough called the atonic gout, as if there were a gout accompanied with vigour and sthenic diathesis: but the absence of inflammation in the extremities may depend on two causes. First, the powers producing the disease, may have debilitated the stomach and first passages, while the vessels of the extremities are not particularly debilitated, and the resisting force is able to counterbalance the propelling force: in this case, no morbid degree of distention or inflammation of the extreme vessels can take place. Secondly, the general debility may be such, and the power of the circulation so much diminished, that, though the extreme vessels may be debilitated, no inflammation, or preternatural distention will take place. Hence, we see, that this is still the same disease; but that physicians have erred in their explanation of the symptoms, by regarding that as the principal part of the disease, which is only a symptom. We have seen then, that by the theory which has been unfolded, all the symptoms of this hitherto mysterious disease are plainly and naturally explained. We shall next see if the only method of cure which experience warrants, cannot be explained upon the same principles. If, on entering this part of the subject, any one should expect that I should furnish him with a receipt, consisting of certain drugs, which swallowed, will cause this terrible disease to disappear, and health to take its place, he would be very much mistaken; for, can any person in his senses suppose that a disease, which he has been almost his whole life in contracting, and an exhausted state of the excitability, which has been gradually brought on by years of intemperance, can be dispersed by a pill, a powder, or a julep? Or, if the symptoms could be relieved by medicine, which they often may, can he suppose, that they will not return, if the same mode of living, which first brought them on, be continued? I shall, however, proceed to give some directions, which if rigidly persevered in, will not only afford relief in the fit, but will prevent its return with such violence, and at last totally eradicate it, provided the constitution be not completely exhausted, and almost every joint stiffened with calcarious concretions. The inflammation of the extremities may at any time be relieved by means of electricity, or by stimulant embrocations applied to the part, and this without any danger whatever of throwing the complaint on some more vital part, as has generally been imagined. If I were to apply any debilitating means to the part, I should then probably relieve the pain; but, by debilitating the whole system, should cause an attack of the stomach, or some other internal part, as has been already explained; but by a stimulant application to the inflamed part I run no such risk. The inflammation is of the asthenic kind, depending upon a debility of the small vessels, whereby they do not afford sufficient resistance to the propelling force, and therefore become morbidly distended, or inflamed, as it is termed, though this term is certainly improper, even in a metaphorical view: but a stimulant application to the part excites the debilitated vessels to action; their contraction diminishes the morbid quantity of blood; and the balance between the propelling and resisting forces being restored, the inflammation of course ceases. This is not a mere deduction, a priori, from the theory of inflammation, which I have delivered; it is the result of repeated experience. I have seen several very violent gouty inflammations very speedily removed by electricity. Small sparks should be drawn from the part affected, at first through flannel, and increased as the patient can bear them: sparks alone are necessary; recourse need never be had to shocks. But though we thus remove a very painful part of the disease, yet still a formidable debility remains, and unless this be removed, the inflammation will be apt to return. In endeavouring to remove this general debility, we must recollect, that it is of the indirect kind, or depends upon an exhausted state of the excitability; our great object therefore, is to allow the excitability to accumulate. But this accumulation depends as well upon the proper action of the different functions, as upon the withdrawing of stimulants: we ought therefore to guard carefully against costiveness, by which the proper action of the stomach and bowels is very much injured: but we must use warm laxatives. An infusion of senna and rhubarb in proof spirits, made still stronger by aromatics, has always seemed to me to answer the purpose best, and this should be taken of a temperature rather above blood warm; for instance, about 100 degrees. This is particularly necessary, when the gout attacks the stomach, and I have several times seen a severe attack of it removed in half an hour, by a tincture of this kind. Indeed, the most violent attacks of the stomach may be relieved; and are only to be relieved by spirits, ether, and opium. It is on this organ, that the hurtful powers have produced their greatest effect; for to it they are immediately applied. It is by no means surprising, that the constant application of highly seasoned foods, with fermented and spirituous liquors, should at last wear out the vital principle of this organ. Indeed it is often so far exhausted, that the most terrible cramps and convulsions take place, which would soon end in its total extinction, unless it were roused to somewhat like a proper action by the most powerful stimulants. Still, however, their effect is but temporary. With respect to a regular fit, after the inflammation of the extremities has been subdued by the means I have mentioned, a generous, but not full diet should be used. A person who has been for a long time accustomed to wine, cannot easily be deprived of it at once; but he should drink Madeira, and those wines, which neither contain much carbonic acid, nor deposite much tartar. His food should be of the plainest kind, and generally boiled, instead of roast. The great thing is to keep the spirits and excitement rather under par, but not to let the patient sink too low. In this way, the exhausted excitability will gradually accumulate, and the healthy state be reestablished. When this is once effected, the gout may be prevented in future with the greatest certainty, if the patient will have resolution. The whole secret consists in abstaining, in toto, from alcohol, in every form, however disguised, or however diluted. He must not take it, either in the form of liqueurs, cordials, wine, or even small beer. I believe there never was an instance of a person having the gout, who totally abstained from every form of alcohol, however he might live in other respects: and I doubt very much, if ever the gout returned after a person had abstained from fermented or spirituous liquors for two years. Temperance in eating, and exercise, are, no doubt, powerful auxiliaries, and tend very much to promote health; but still they will not secure a person from a return of the gout, without this precaution. There seems something in alcohol, which peculiarly brings on this state of the constitution, and without it, it would seem that gout could not be produced. Here then is an effectual method of curing the gout, which will no more return, if this method be strictly persevered in, than the smallpox will attack the constitution after inoculation. During the fit therefore, I would say, nearly in the words of Dr. Darwin, Drink no malt liquor on any account. Let the beverage at dinner consist of two glasses of Madeira, diluted with three half pints of water; on no account whatever drink any more wine or spirituous liquors in the course of the day. Eat meat constantly at dinner, without any seasoning, but with any kind of tender vegetables, that are found to agree. When the fit is removed, use the warm bath twice a week, an hour before going to bed, at about 93 degrees, or 94 degrees of heat. Keep the body open by means of lenitive electuary and rhubarb; for there is an objection to the tincture I mentioned, as containing alcohol. Use constant, gentle exercise; but never so violent as to bring on great fatigue. The grand secret, however, in the cure, as has been already observed, but which cannot be too often inculcated, is to abstain, in toto, from every thing that contains alcohol. In short, though in acute diseases medicines are highly useful, a chronic disease can never be cured, and the healthy state reestablished, by them alone. To effect a cure in such cases, we must reform our mode of life, change our bad habits into good ones; and then, if we have patience to wait the slow operations of nature, we shall have no reason to regret our former luxuries. LECTURE XIV. NERVOUS COMPLAINTS, &c. In this lecture I propose to take a view of some of those affections, which have been commonly, but improperly known by the appellation of nervous complaints, because it has been supposed by many that they are owing to a deranged state of the nerves, which, however, is by no means the case; for I hope to be able to make it appear, that these symptoms arise from a general affection of the excitement of the system. In short, by far the greater number of these complaints, arise from such a state of the excitement as approaches predisposition, or perhaps ranges between predisposition and disease, but does not in general actually reach disease; or rather, it is a state of the excitement, so far departing from the point of perfect health, that the functions are not performed with that alacrity, or vigour, which ought to take place; but labour under that disturbed and uneasy action, which, though it cannot be called actual disease, yet deviates considerably from the point of perfect health. This is a new view of these diseases, but the more I have examined it, the more I am convinced that it is just. Indeed, the name, nervous, has generally been given to an assemblage of symptoms, which the physicians did not understand; and when the patient relates a history of symptoms, and expects that his physician shall inform him of the name, and nature of his complaint, he generally receives for answer, that his complaints are nervous, or bilious; terms which convey no distinct ideas, but which serve to satisfy the patient, and to conceal the ignorance of the physician, or spare him the labour of thinking. Indeed, the idea of nervous diseases, which I have already pointed at, is not only new, but could only have arisen from such a view as we have been taking of the states of excitement and excitability. This view will not only lead us to form a more just idea of the manner in which these diseases originate, but will point out a distinction of them into two classes, of the utmost use in practice, but which distinction has totally escaped the attention of practitioners; for though these complaints have been generally thought to arise from a lowness of the nervous energy, or some kind of debility, or weakness of the nervous system, and, on this account, the stimulant and cordial plan of cure has been recommended, I am convinced, from observation, that nearly one half of them, if not more, originate from a state of the excitement verging towards sthenic disease; and in these cases, this general mode of treatment must be highly improper. It has been already shown, that when the common exciting powers which support life, act in such a manner, that a middle degree of exciting power, acts upon a middle degree of excitability, the most perfect state of the system, or a state of perfect health, takes place: it is, however, seldom in our power so to proportion the state of excitement and excitability to each other. The action of the exciting powers is continually varying in strength; and the excitability, from a variety of stimulants, and other circumstances, which are not entirely under our direction, is sometimes more, and sometimes less abundant, than this middle degree. There is, however, a considerable latitude, on each side the point of health, within which the excitement may vary, and yet no disease, nor any disturbance of the functions may take place: but this has its limits, beyond which if the excitement be brought, on either side, it is evident that an uneasy or unpleasant exercise of the functions must take place. There is not, however, any precise line or boundary between this state, and that in which the functions begin to be disturbed; on the contrary, the law of continuity and gradation seems to extend throughout every part of nature. This departure from the healthy state, and approach to disease, in which what has been called the nervous state consists, is gradual and scarcely perceptible; but is apt to be produced by any circumstances, which lead the excitement beyond its proper limits. Nervous complaints may therefore be divided, like all other diseases, into two classes. First, those in which the excitement is increased, or in which it verges to, or has actually reached, the point of predisposition to sthenic disease; Secondly, those in which the excitement is diminished, or in which it verges towards asthenic disease. This last class, as has been done before, may be subdivided into two orders. The first will comprise those diseases in which the excitability is sufficiently abundant, or even accumulated, but where the excitement is deficient from a want of energy in the exciting powers. In the second, there has been no deficiency in the action of the exciting powers; but on the contrary, probably for a considerable time, some of the diffusible stimuli not natural to life have been applied; in this case, the excitability has become exhausted, and a proper degree of excitement cannot be produced by the action of the common exciting powers. No diseases show so clearly the fallacy of trusting to symptoms, as those of the former class. I have met with innumerable cases of this kind, in which, if you were to trust to the patients own description, they laboured under considerable debility; and had it not been for the particular attention I paid to my own case, I should not probably have suspected that a directly opposite state of the system may produce these symptoms. From inheriting a good constitution, and being brought up in the country in a hardy manner, I am so much predisposed to the sthenic state, that I may consider the state of my excitement, as generally, indeed almost always, above the point of health: and unless I live in the most temperate, and even abstemious manner, the excitement is extremely liable to overstep the bounds of predisposition, and fall into sthenic disease. I have had several attacks of this kind of disease; and indeed, I never remember to have laboured under any disease of debility, or diminished excitement. Health, according to the view we have taken of it, may be compared to a musical string, tuned to a certain pitch, or note; and though perhaps in the great bulk of mankind, either from the manner of living, or from other circumstances, the excitement is a little below, and requires to be screwed up to the healthy pitch, yet there are others where it is apt to get constantly above, and where it requires letting down to this pitch; my constitution is one of these: but I have this consolation, that if I can for a few years ward off the fatal effects of some acute sthenic diseases, this tendency to sthenic diathesis will gradually wear off, and I may probably enjoy a state of good health, at a time, when most constitutions of an opposite cast begin to give way. Whenever I have for some time lived rather fully, though by no means intemperately, after having for some days, or perhaps some weeks experienced an unusually good flow of spirits, and taken exercise with pleasure, I begin, first of all, to have disturbed sleep, I find myself inclined to sleep in the morning, as if I had not been refreshed by the night's sleep; my spirits become low, and I am apt to look upon the gloomy side of every thing I undertake or do. I feel a general sense of languor and debility, and am ready, as I have heard many patients labouring under the same state exclaim, to sink into the earth. From the slightest causes, I am apt to apprehend the most serious evils, and my temper becomes irritable, and scarcely to be pleased with any thing. If in this state, I take exercise, I soon feel myself fatigued; a disagreeable stupor comes on, without, however, the least degree of perspiration, and I feel an inability to move. At first, I used to imagine these to be symptoms of debility, or diminished excitement, nor was it till after several ineffectual trials to relieve them by the tonic, or stimulant plan, that I was convinced of my mistake. This plan always caused an aggravation of every symptom, and if I persevered in it, an inflammatory disease was sure to be the consequence. Indeed, I might have suspected this, from considering, that these symptoms had been brought on by full living, and preceded by good spirits; but my mind had received such a prejudice from the writings of medical men, who had uniformly described these as a train of nervous symptoms, as they called them, depending on a debilitated state of the nervous system, that I was blind to conviction, till repeated disappointment from the stimulating plan, convinced me I must be wrong. The only alternative therefore, was a contrary plan, and the immediate relief I experienced, was a proof that I had detected the real nature of the complaint. Since that time, I can at any time prevent these unpleasant symptoms, by an abstemious course of life, and remove them, when they have come on, by the debilitating plan; which, instead of weakening, gives additional elasticity and strength to the fibres, and alacrity to the spirits. I have described the symptoms in one case, as this will serve as a general description. We may add, that persons labouring under this kind of predisposition, are particularly attentive to the state of their own health, and to every change of feeling in their bodies; and from every uneasy sensation, perhaps of the slightest kind, they apprehend great danger, and even death itself. In cases of this kind, the bowels are generally costive, and the spirits of the patient are very apt to be affected by changes in the weather, particularly by a fall of the barometer. How the diminution of atmospheric pressure acts in increasing the symptoms, we perhaps do not know; but its effects are experienced almost universally. It is evident, that the only mode of cure in cases of this kind is extreme temperance: animal food should be taken sparingly, and wine and spirits in general totally abstained from. The bowels should be kept open by any mild neutral salt. I have generally found magnesia and lemonade to agree remarkably well in such cases. Exercise on horseback, is also particularly useful; bark, bitters, and the fetid and antispasmodic medicines, which are generally prescribed in such cases, are extremely hurtful. This view of nervous complaints is, I may venture to say, as new as it is just. It has never been imagined, that any of them depended upon too great excitement; on the contrary, they have been universally considered as originating in debility, and of course, tonics were prescribed, which, though they produced the greatest benefit in the other class of nervous complaints, in these they occasioned the most serious evils, and often brought on real inflammatory diseases, or even diseases of indirect debility, as I have repeatedly seen. These cases cannot at first sight, however, be easily distinguished from those of the opposite class; the symptoms being nearly alike, and the patient complaining of languor, debility, and extreme depression of spirits in both. But by attending carefully to the effects produced by the exciting powers, they may in general be distinguished. A patient of this kind will tell you, that he does not feel pleasant effects from wine, or spirituous liquors; instead of exhilaration, his spirits become depressed by them; whereas, in the contrary state, he finds almost instant relief. By attending to circumstances of this kind, the nature of the complaint may in general be ascertained. Highly seasoned, and strongly stimulant foods should in the sthenic hypochondriasis, if it may be so called, be avoided; but the most mischievous agent of all, and which contributes to bring on the greater number of these complaints, is wine. This, I believe, produces more diseases, than all other causes put together. Every person is ready to allow, that wine taken to excess is hurtful, because he sees immediate evils follow; but the distant effects, which require more attentive observation to perceive, very few see, and believe; and, judging from pleasant and agreeable feelings, they say that a little wine is wholesome, and good for every one; and accordingly take it every day, and even give it to their children; thus debauching their natural taste in the earliest infancy, and teaching them to relish what will injure their constitutions; but which, if properly abstained from, would prove one of the most valuable cordial medicines we possess. The idea that wine or spirituous liquors assist digestion, is false. Those who are acquainted with chemistry, know that food is hardened, and rendered less digestible by these means; and the stimulus, which wine gives to the stomach, is not necessary, excepting to those who have exhausted the excitability of that organ, by the excessive use of strong liquors. In these, the stomach can scarcely be excited to action, without the assistance of such a stimulus. If the food wants diluting, water is the best diluent. Water is the only liquor that nature knows, or has provided for animals; and whatever nature gives us, is, we may depend upon it, the best, and safest for us. Wine ought to be reserved as a cordial in sickness, and in old age; and a most salutary remedy would it prove, did we not exhaust its power by daily use. I am sensible that I am treading on delicate ground, but I am determined to speak my sentiments with plainness and sincerity, since the health and welfare of thousands are concerned. Most persons have so indulged themselves in this pernicious habit of drinking wine, that they imagine they cannot live without a little every day; they think that their very existence depends upon it, and that their stomachs require it. Similar arguments may be brought in favour of every other bad habit. Though, at first, the violence we do to nature makes her revolt; in a little time she submits, and is not only reconciled, but grows fond of the habit; and we think it necessary to our existence: neither the flavour of wine, of opium, of snuff, or of tobacco, are naturally agreeable to us: on the contrary, they are highly unpleasant at first; but by the force of habit they become pleasant. It is, however, the business of rational beings to distinguish carefully, between the real wants of nature, and the artificial calls of habit; and when we find that the last begin to injure us, we ought to use the most persevering efforts to break the enchantment of bad customs; and though it cost us some uneasy sensations at first, we must learn to bear them patiently; a little time will reward us for our forbearance, by a reestablishment of health and spirits. I shall now proceed to examine the opposite class of nervous complaints: or such as do really depend on debility, or an asthenic state of the system. These may be divided into two orders; viz. those of direct, and those of indirect debility. I shall first consider those of direct debility. Though these complaints originate from a deficiency of stimulus, yet it is very seldom from a deficiency of the common stimulant powers. The only people, who in general labour under this deficiency of the common stimulants, are the poor; they are seldom troubled with nervous complaints; their daily exercise, and constant attention to procure common necessaries, prevent their feeling what so grievously afflicts the rich and luxurious. These complaints arise chiefly from a deficiency of mental stimuli. The most common cause of them, and whose effects are the most difficult to remove, is to be looked for in the mind. The passions and emotions, when exercised with moderation, and kept within proper bounds, are the sources of life and activity; without these precious affections, we should be reduced to a kind of vegetation, equally removed from pleasure and from pain. For want of these elastic springs, the animal spirits lose their regularity and play; life becomes a lethargic sleep, and we fall into indifference and languor. If then the passions are so necessary to the support of the health of the body, when in a proper degree, can we expect, that when they are inordinate or excessive, or even deficient, we shall escape with impunity? tumultuous passions are like torrents, which overflow their bounds, and tear up every thing before them; and mournful experience convinces us, that these effects of the mind are easily communicated to the body. We ought, therefore, to be particularly on our guard against their seduction. "'Tis the great art of life to manage well The restless mind." It is particularly in their infancy, if it may be so called, that we ought to be upon our guard against their seduction; they are then soothing and insidious; but if we suffer them to gain strength, and establish their empire, reason, obscured and overcome, rests in a shameful dependence upon the senses; her light becomes too faint to be seen, and her voice too feeble to be heard; and the soul, hurried on by an impulse to which no obstacle is presented, communicates to the body its languor and debility. The passions, by which the body is chiefly affected, are, joy, grief, hope, fear, love, hatred, and anger. Any others may be reduced to some of these, or are compounded of them. The pleasurable passions produce strong excitement of the body, while the depressing passions diminish the excitement; indeed it would seem that grief is only a diminution of joy, as cold is of heat; when this passion exists in a proper degree, then we feel no particular exhilarating sensation, but our spirits and health are good: we cannot doubt, however, that we are excited by a pleasant sensation, though we are unable to perceive it. In the same manner, when heat acts moderately, or is about the degree we call temperate, we do not perceive its effects on the body, though there can be no doubt, that the body is under the influence of its stimulus, and powerfully excited by it; for when it is diminished, or cold applied, we feel a deficiency of excitement, and become afterwards more sensible of heat afterwards applied. The same takes place with respect to joy and grief, and proves, I think, clearly, that the one is only a diminution of the other, and that they are not different passions. When the body has been exposed to severe cold, the excitability becomes so much accumulated with respect to heat, that if it be afterwards applied too powerfully, a violent action, with a rapid exhaustion of the excitability, which ends in mortification, or death of the part, will take place. We should therefore apply heat in the gentlest manner possible, and gradually exhaust the morbidly accumulated excitability. In the same manner, when the body has been under the influence of violent grief, any sudden joy has been known to overpower the system, and even produce instant death. We have an instance in history, of a mother being plunged into the extreme of grief, on being informed that her son was slain in battle; but when news was brought her, that he was alive, and well, the effect upon her spirits was such, as to bring on instant death. This event ought to have been unfolded to her in the most gradual manner; she should have been told, for instance, that he was severely wounded; but that it was not certain he was dead; then that there was a report he was living, which should have been gradually confirmed, as she could bear it. The same observations may be made, with respect to hope and fear, or despair; the former is an exciting passion, the latter, a depressing one; but the one is only a lower degree of the other; for a moderate degree of hope produces a pleasant state of serenity of the mind, and contributes to the health of the body; but a diminution of it weakens; and a great degree of despair so accumulates the excitability of the system, as to render it liable to be overpowered by any sudden hope or joy afterwards applied. What proves that joy and hope act by stimulating, and grief and despair by withdrawing stimulant action from the body, is, that the former exhaust excitability, while the latter accumulate it. Joy, for instance, does not render the system more liable to be affected by hope, but the reverse; and the same may be said of hope. In the same way, heat does not render the body more liable to be affected by food, but the reverse. Both these are stimulants, and exhaust the excitability. But after heat has been applied, if it be followed by cold, a great degree of languor or weakness will take place; because we have here a direct debility, added to indirect debility. In the same way, grief succeeding joy, or despair succeeding hope, produce a greater degree of dejection, both of mind and body, than if they had not been preceded by these stimulant passions; because here, direct debility is added to indirect. The excitability is first exhausted, and then the stimulus is withdrawn. We see then, that the passions of the mind act as stimulants to the body, that, when in a proper degree, they tend to preserve it in health; but when their action is either too powerful, or too small, they produce the same effects as the other powers. We should therefore naturally expect, that when there is a deficient action of this kind of mental stimulus, or when the mind is under the influence of the depressing passions, a predisposition to diseases of direct debility would take place, and even these diseases be produced. Accordingly we find a numerous class of nervous complaints originating from these causes. Indeed, the undue action of the mental stimulants, produces more quick alterations in the state of the excitement, than that of the other exciting powers. Violent grief, or vexation, will immediately suspend the powers of the stomach. If we suppose a person in the best health, and highest good humour, sitting down to dinner with his friends, if he suddenly receives any afflicting news, his appetite is instantly gone, he cannot swallow a morsel. If the same thing happens after he has made a hearty dinner, the action of the stomach is suddenly suspended, and the whole process of digestion stopped, and what he has eaten, lies a most oppressive load. But this is not all: the whole circulation of the blood becomes disturbed; the contraction and dilatation of the heart become irregular; it flutters, and palpitates; hence all the secretions become irregular, some of the glands acting too powerfully, others not at all; hence the increased action of the kidneys, and hence a burst of tears; hysterical affections, epilepsy, and syncope, frequently succeed, in which every muscle of the body becomes convulsed. Indeed, many terrible diseases originate from this source, which were formerly ascribed to witchcraft, and the possession of devils. In slower, more silent, but longer continued grief, the effects are similar, but not so violent. The functions of the stomach are more gently disturbed, its juices vitiated; and acidity, and other symptoms of indigestion, will show themselves. Hence no bland and nutritive chyle is conveyed into the blood; whence emaciation and general debility must follow; and the patient will at last die, as it is said, of a broken heart. Besides the disturbed state of the stomach, and bad digestion, there can be no sleep in this state of mind; for, "Sleep, like the world, his ready visit pays, Where fortune smiles; the wretched he forsakes; Swift on his downy pinion flies from woe, And lights on lids unsullied with a tear." Hence the animal spirits will not be recruited, nor the worn out organs restored to vigour. The minds of patients labouring under this division of nervous diseases, are likewise in general filled with over anxiety concerning their health; attentive to every feeling, they find, in trifles light as air, strong confirmations of their apprehensions. It is evident, that in these cases, a state of direct debility prevails, attended with a morbidly accumulated excitability; hence, those remedies afford relief, which produce a quick exhaustion of this principle, and thus blunt the feelings, and lull the mind into some degree of forgetfulness of its woes. Hence opium, tobacco, and the fetid gums are often resorted to; and in the hands of a judicious practitioner, they will afford great relief, provided he carefully watch the patient, and prevent their abuse; for, if left to the discretion of the patient, he finds that kind of relief which he has long wished for; his moderation knows no bounds, and he is apt to take them in such a manner, as to add indirect debility, to direct, and thus bring on a state of exhausted excitability, while there is still a diminished state of mental stimulants. This will cause his spirits to be more depressed than ever; he will therefore increase the dose, whether it be of opium, tobacco, or spirituous liquors, and thus he will be hurried on, adding fuel to the flame, till his exhausted excitability becomes irrecoverable, and he ends his days in a miserable state of imbecility, if not by suicide. Hence, though some of these narcotic stimulants, which exhaust the excitability, and blunt the feelings, may be employed with advantage, in order to prepare the mind for those changes, which the physician wishes to produce, they should be used with the greatest caution, and never left in any degree to the discretion of the patient. The cure, however, depends chiefly on regulating the state of the mind, or interrupting the attention of the patient; and diverting it, if possible, to other objects than his own feeling. Whatever aversion to application of any kind we may meet with in patients of this class, we may be assured that nothing is more pernicious to them than absolute idleness, or a vacancy from all earnest pursuit. The occupations of business suitable to their circumstances, and situations in life, if neither attended with emotion, anxiety, nor fatigue, are always to be advised to such patients; but occupations which are objects of anxiety, and more particularly such as are exposed to accidental interruptions, disappointments, and failures, are very improper for patients of this class. To such patients exercise in the open air is of the utmost consequence. Of all the various methods of preserving health and preventing diseases, which nature has suggested, there is none more efficacious than exercise. It puts the fluids all in motion, strengthens the solids, promotes digestion, and perspiration, and occasions the decomposition of a larger quantity of air in the lungs, and thus not only more heat, but more vital energy is supplied to the body; and of all the various modes of exercise, none conduces so much to the health of the body, as riding on horseback: it is not attended with the fatigue of walking, and the free air is more enjoyed in this way, than by any other mode of exercise. The system of the vena portarum, which collects the blood from the abdominal viscera, and circulates it through the liver, is likewise rendered more active, by this kind of exercise, than by any other, and thus a torpid state, not only of the bowels, but of this system of vessels, and the biliary system, is prevented. When a patient of this class, however, goes out for the sake of exercise only, it does not in general produce so good an effect, as might be expected; for he is continually brooding over the state of his health: there is no new object to arrest his attention, and he is constantly reminded of the cause of his riding. Exercise will therefore be most effectual when employed in the pursuit of a journey, where a succession of pleasant scenes are likely to present themselves, and new objects arise, which call forth his attention. A journey likewise withdraws the patient from many objects of uneasiness and care, which might present themselves at home. With respect to medicines, costiveness, which often attends these diseases, ought to be carefully avoided, by some mild laxative. Calcined magnesia, and lemonade, have always seemed to me to answer the purpose; but the most effectual method is to acquire a regular habit, which may be done by perseverance, and strict attention. Chalybeate waters have been frequently tried, and may in general be recommended with success, particularly, as the amusement and exercise generally accompanying the use of these waters, aid the tonic powers of the iron. The bark may likewise be exhibited with advantage. There is yet another class of nervous diseases which we have to notice, which are by no means uncommon; yet they have, like the first class, escaped the attention of writers on this subject, and of medical practitioners in general: I mean those where the system is in a state of torpor, or exhausted excitability. This state of the system may be brought on by various causes, but principally by the long continued use of opium, tobacco, or fermented liquors. When these substances, which are powerful stimulants, have been taken for some time, they bring on a state of the system so torpid, that the usual exciting powers, and the usual occurrences, which in general produce pleasant sensations, do not occasion a sufficient degree of excitement, in those whose excitability is thus exhausted. They therefore feel continual languor and listlessness, unless when under the influence of the stimulus which brought on the exhaustion. Every scene, however beautiful, is beheld with indifference by such patients, and the degree of ennui they feel is insupportable: this makes them have recourse to the stimulus which has exhausted their excitability, which in some degree removes this languor for a time; but it returns with redoubled strength, and redoubled horror, when the stimulant effect is over: and as this repetition exhausts the excitability more and more, the stimulus is repeated in greater quantity, and thus the disease increases to a most alarming degree. There is no way of curing this state of nervous torpor, but by leaving off the stimuli which caused the exhaustion; and if the patient have resolution to do this for a few weeks, though, at first, he will, no doubt, find his spirits a little depressed, he will ultimately overcome the habit, and will be rewarded by alacrity of spirits, such as he never experiences under the most powerful action of artificial stimulants. I must not, however, forget to notice, that there is a nervous state, or ennui, originating from a wrong direction of mental exertion, which exhausts the excitability to a great degree, and brings on a state of depression scarcely to be born. When a person has by habit made his mind constantly dependent on dissipation, on gaming, and on frivolous, but not inactive pursuits, in order to produce pleasurable sensations, and at the same time neglected that culture of the understanding which will enable him to retire into himself with pleasure, and receive more enjoyment from the exercise of this cultivated understanding than he does in the most noisy, or fashionable circle of dissipation: I say, when there is this vacancy of mind, whenever it is not engaged in such pursuits as I have mentioned, a languor and weariness is experienced, which is intolerable, and which prompts the person so circumstanced, to fly continually to the only scenes which interest his mind. Hence, the passion for gaming, in which the anxiety attending it causes an interest in the mind, which takes off the dreadful languor experienced, when it is not thus employed. It is owing to wealth, admitting of indolence, and yielding to the pursuit of transitory and unsatisfying amusements, or to that of exhausting pleasures only, that the present times exhibit to us so many instances of persons suffering under this state: it is a state totally unknown to the poor, who labour for their daily bread, and to those whose minds are actively employed in study or business. It can only be cured by cultivating the understanding, and applying to some art or science, which will engage and interest the attention. I have received the thanks of many for recommending the study of philosophy, and particularly of chemistry, to their attention. This affords a rational and interesting pursuit, which, if entered into with ardour, and if the person actually works, or makes experiments himself, he will soon experience an enjoyment and an interest, such as he never experienced at the gaming table, or at any other place of fashionable amusement. Nay, I will venture to say, that all elegant amusements will be enjoyed with much greater relish by one who employs himself in some rational pursuit, and only resorts to such amusements as a relaxation, than by one who makes these amusements a business. From the view we have taken of these complaints, it is evident, that they are like other general diseases of the sthenic, or asthenic kind; they seem to constitute a state of the body between predisposition and disease; and they differ from most diseases in this, that in most complaints the increase, or diminution of the excitement is unequal in different parts of the body, and this gives rise to the different forms of disease; but in nervous complaints the excitement seems much more equably affected in different parts. These complaints, as we have seen, may be divided into three classes; sthenic; those of accumulated excitability; and those of exhausted excitability: but though they are evidently distinguishable in this manner, and require different modes of cure, I have never seen any account of more than one kind in any medical writer: the same remedies were prescribed for all, however different they might be. Though medicines may relieve complaints of this kind, and particularly those of the second class, yet from what has been said, it must be evident, that much more may be done by regulating the action of the common exciting powers. Indeed, this is the case in most chronic diseases. Exercise and temperance will do infinitely more than medicine. By their means, most diseases may be overcome; but without them we may administer drugs as long as we please. Voltaire sets this advice, which I have frequently inculcated, in so strong a light, that it may perhaps carry more conviction than any thing I can say. Ogul was a voluptuary, ambitious of nothing but good living: he thought that God had sent him into the world for no other purpose than to eat and drink: his physician, who had but little credit with him, when he had a good digestion, governed him with despotic sway, when he had eaten too much. On feeling himself much and seriously indisposed by indolence and intemperance, he requested to know what he was to do, and the doctor ordered him to eat a basilisk, stewed in rose water, which he asserted would effect a complete cure. His slaves searched in vain for a basilisk; at last they met with Zadig, who was introduced to this mighty lord, and spoke to him in the following terms. "May immortal health descend from Heaven to bless all thy days! I am a physician: at the report of thy indisposition, I flew to thy castle, and have now brought thee a basilisk, stewed in rose water. But, my lord, the basilisk is not to be eaten; all its virtue must enter through thy pores. I have enclosed it in a little ball, blown up and covered with a fine skin. Thou must strike this ball, with all thy might, and I must strike it back for a considerable time: and by observing this regimen for a few days, thou wilt see the effects of my art." The first day Ogul was out of breath, and thought he should have died with fatigue; the second he was less fatigued, and slept better. In eight days he recovered all the strength, all the health, all the agility and cheerfulness of his most agreeable years. Zadig then said unto him, "there is no such thing in nature as a basilisk; but thou hast taken exercise, and been temperate, and hast recovered thy health." In the same manner I say, that temperance and exercise are the two great preservers of health, and restorers of it when it is lost; and that the art of reconciling intemperance and health is as chimerical, as washing the Ethiopian white. It will easily be perceived that the system of animal life which I have investigated, may be applied to all other general diseases, as well as the gout and those called nervous: I have merely given a view of these by way of specimen of its application. Should these lectures contribute in any degree to lessen the future sufferings of my hearers, or any of their friends, I shall not have delivered them in vain. To be assured of this, would be the greatest pleasure that I could receive. THE END. From the Press of the Royal Institution of Great Britain, Albemarle Street, London: W. Savage, Printer. INDEX. A. _Air_, its properties--its components _Animals_, specific temperature of _Appetite_, artificial _Arteries_, their structure and office _Assimilation_, from the blood _Attention_, fixed on new objects B. _Banks, Sir Joseph_, his almost fatal experience of cold _Beddoes, Dr._ his remarks on temperature, _Bile_, its properties _Blood_, difference between arterial and venous contains iron changes produced on, by the different gases assimilation from _Bones_, mechanism of structure of _Brown, Dr. John_, his example followed declines a definition of excitability denies the existence of sedatives his cure of diseases of exhaustion objected to his theory will be as durable as Newton's philosophy not aware of the extent of his own theory C. _Camera obscura_ _Colour_ of different nations _Cooper, Mr. Astley_, successfully perforates the tympanum of the ear _Circulation_ of the blood through the lungs through the liver affected by centrifugal force discovered by Harvey, and derided _Cullen, Dr._ his system defective _Currie, Dr._ his treatment of typhus D. _Darwin, Dr._ quoted _Digestion_, organs of process of diseases affecting _Diseases_ sthenic asthenic fallacy of symptoms _Diseases_, method of cure spasmodic, of extreme vess. classification of nervous and bilious (so called) of the poor _Dollond, Mr._ his achromatic lenses, first suggested by Dr. David Gregory E. _Ear_, description of diseases of tympanum perforated _Electricity_, phenomena of useful in gout _Excitability_, or vital principle how affected by heat, food, air, &c. accumulated by sleep three states of its accumulation, and exhaustion illustrated an unknown indefinable somewhat connected with oxygen hypothesis respecting this connexion scale of how to be regulated in gout _Exercise_ on horseback, best _Eye_, description of vertical section of its accommodating power F. _Food_, animal and vegetable in gout G. _Galvanism_, its identity with electricity accompanies oxydation _Gaming_, &c. deplorable effects of, on the mind _Gases_, their proportions in the atmosphere changes they produce on the blood _Gastric Juice_, dissolves food proved by experiment _Gout_ denied to be salutary, or incurable not to be cured by drugs not hereditary mode of attack depends not on morbific matter its inflammation asthenic its symptoms and description its remissions accounted for the terms retrocedent, atonic, &c. misapplied mode of cure electricity useful Dr. Darwin's advice Diet and medicine in _Gravity_, the circulation affected by it H. _Habit_, its power _Harvey_, discovers the circulation of the blood, and is opposed _Health_ previous to disease, investigated point of, on the scale _Heart_, description of _Heat_, its combinations animal, accounted for its effects on the system how it affects vegetables its debilitating effects exemplified _Hunger_ and _thirst_ _Hunter, Mr. John_, dissects torpedo, and electrical eel I. _Inflammation_, illustrated sthenic asthenic of gout asthenic _Iron_, contained in the blood L. _Lacteals_, described _Life_, principle of _Light_, its properties its exciting power _Lungs_, circulation through _Lymphatics_ described M. _Muscles_, mechanical action of _Music_, its effects N. _Nerves_, their distribution _Nervous_ and _bilious_, terms sometimes used without ideas diseases (so called) diseases really so _Newton_, his query about elastic fluid misapplied even his conjectures important discovers the laws of sound his reason why the crystalline is densest in the middle knew not the cause of gravitation _Nonnaturals_, misapplication of that term _Nosology_ O. _Odours_, extreme subtilty of Haller, &c. fail in classing them convey nourishment _Opium_, its intoxicating effects its use in gout _Organs_, digestive _Oxygen_, experiments with connected with excitability P. _Pain_ encreases mental energy _Passions of the mind_, their effects _Pendulums_, laws of _Peristaltic motion_ _Physiology_, its importance _Pulse_, the phenomena of R. _Respiration_, organs of how performed analogous to combustion chemically explained S. _Schools_, their temperature ill regulated _Sensation_ organs of more acute by pain _Senses_, general account of external and internal _Skin_ _Sleep_, accumulates excitability _Smell_ different in different animals Blumenbach's opinion on diseases of _Sound_, production of media of illustrated velocity of musical reflection of _Spallanzani_, his experiments on digestion _Spirituous liquors_, their effects a singular mode of correcting the abuse of _Squinting_, &c. method of cure _Stomach_ diseases of _Study_, debilitating effects of T. _Taste_ diseases of _Temperancc_ _Temperature_ of animals, specific and uniform _Touch_ the basis of the other senses _Typhus_, Dr. Garnett's treatment of Dr. Currie's ditto V. _Veins_, their structure and office _Vision_, manner of opinions on seat of why objects appear erect why seen single diseases and cure of _Voltaire_, his story of Ogul, the epicure W. _Water_, the best diluent _Wine_, its use and abuse LIST OF SUBSCRIBERS. _L. s._ A. Henry Ainslie, M.D. 10 10 James Peter Auriol, Esq. P.R.I. 5 5 James Acheson, Esq. _Oaks, Londonderry_ 1 1 W. Dacre Adams, Esq. 1 1 Miss Adams 1 1 Mr. Adams, _Optician_ 5 5 ------Addington, Esq. 1 1 Mr. Thomas Addison, _Preston_ 2 2 Mrs. Addison 2 2 John Aikin, M.D. 1 1 Mr. Arthur Aikin 1 1 Charles R. Aikin, Esq. _Surgeon_ 1 1 William Alers, Esq. 2 2 Dr. Alexander, _Hallifax_ 2 2 Henry Alexander, Esq. 1 1 E. Alexander, M.D. _Leicester_ 1 1 William Allen, Esq. F.L.S. 2 2 Robert Anderson, Esq. 1 1 Dr. Anderson 1 1 Dr. Anderson, _Hammersmith_ 1 1 A. Apsley, Esq. 1 1 Mr. D. Archer, _Bath_ 1 1 Mr. J. T. Armiger 1 1 Nicholas Ashton, Esq. _Liverpool_ 1 1 Mr. Thomas Aston 1 1 Abram Atkins, Esq. 3 3 William James Atkinson, Esq. 3 3 Mr. Accum 10 10 Mr. Noah Ayton 1 1 B. Rt. Hon. Sir Joseph Banks, Bart. K.B. Pr. R.S. F.A.S. P.R.I. F.L.S. 10 10 Sir C. W. Rouse Boughton, Bart. P.R.I. 1 1 Sir William Blizard, F.R.S. F.A.S. 2 2 Mr. B. _Lancaster_ 1 1 Dr. Babington, _Physician to Guy's Hospital._ 3 3 Miss Bacon 1 1 Miss Mary Bacon 1 1 John Bailey, Esq. 1 1 Andrew Bain, M.D. 5 5 John Baker, Esq. 10 10 William Baker, Esq. 10 10 Mr. Joseph Ball 1 1 Rev. Edward Balme 1 1 Mr. Bamford 1 1 Rev. John Banks, P.R.I. _Boston, Lincoln._ 1 1 Mr. Banks, _Leeds_ 1 1 Charles Baratty, Esq. F.A.S. 1 1 Robert Barclay Esq. _Southwark_ P.R.I. F.L.S. 1 1 Mr. William Barclay 1 1 R. J. Barlow, Esq. 3 3 Dr. Barrow 1 1 Rev. William Barton, _Whalley_ 1 1 Mr. Barton 1 1 Thomas Baskerfeild, Esq. F.A.S. 1 1 Jacob Bath, Esq. _Surgeon, 66th Reg._ 1 1 Robert Batty, M.D. P.R.I. F.L.S. 5 5 Mr. Charles Baumer 1 1 E. Bayley, Esq. _St. Petersburg_ 1 11 6 Mr. John Baynes 1 1 Mr. Beckett 1 1 Hugh Bell, Esq. 1 1 William Bell, Esq. _St. Petersburg_ 1 11 6 Mr. Bell 5 5 Christopher K. Bellew, Esq. 2 2 Rev. N. Benezer, _Swaffham_ 1 1 Nathaniel Barnardiston, Esq. 1 1 Thomas Bernard, Esq. P.R.I. 5 5 W. Berwick, Esq. _St. Petersburg_ 1 11 6 Richard Best, Jun. Esq. 1 1 Henry Bickersteth, Esq. _Kirkby Lonsdale_ 2 2 Henry Bickersteth, Jun. Esq. _Kirkby Lonsdale_ 1 1 Mr. John Bickersteth 2 2 Mr. E. Bickersteth 1 1 T. Bigge, Esq. _Newcastle upon Tyne_ 1 1 Mr. George Biggin 1 1 W. Bindsale, Esq. _Pickering, Surgeon_ Charles Binney, Esq. 1 1 Joseph Birch, Esq. M.P. 3 3 Dr. Birkbeck 5 5 Morris Birkbeck, Jun. Esq. _Wanborough, Surry_ 1 1 Thomas Blacker, Esq. P.R.I. 5 5 Mr. Blades 1 1 Alexander Blair, Esq. P.R.I. 5 5 William Blair, Esq. 3 3 Dr. Blake, _Taunton_ 1 1 Dr. Blane 5 5 Mr. Henry Blatch, _Surgeon_ 1 1 Ditto, _2nd Subscription_ 4 4 Ralph Blegborough, M.D. P.R.I. 2 2 John Bliss, Esq. 1 1 Robert Blundell, Esq. 1 1 Samuel Boddington, Esq. P.R.I. 1 1 George Bodley, Esq. 1 1 Thomas Bodley, Esq. 1 1 John Bolton, Esq. 1 1 Dr. Bolton 5 5 Thomson Bonar, Esq. P.R.I. 10 10 George Booth, Esq. 2 2 John Bostock, M.D. 2 2 Josiah Boydell, Esq. 3 3 Daniel Braithwaite, Esq. F.R.S. F.A.S. 5 5 Miss Braithwaite 2 2 Mr. James Braithwaite 1 1 ------Brande, Esq. 1 1 Joseph Brandreth, M.D. 5 5 Mr. Brandreth, _Surgeon_ 3 3 Mr. Brandreth, _Attorney_ 2 2 Messrs. Brash and Reid, _Glasgow_ 2 2 John Breare, Esq. 1 1 Martin Bree, Esq. 1 1 J. H. Brehmer, Esq. _St. Petersburg_ 1 11 6 Brentford Book Society 1 1 William Bridgman, Esq. P.R.I. F.L.S. 1 1 Mr. Richard Briggs 2 2 Mrs. Richard Briggs 1 1 Lowbridge Bright, Esq. _Bristol_ British Library, _St. Petersburg_ 1 1 Theodore Henry Broadhead, Esq. F.A.S. P.R.I. 2 2 Messrs. Broderip 5 5 James Brogden, Esq. M.P. 3 3 Mr. E. Brook 1 1 Joshua Brooks, Esq. _Lecturer on Anatomy, Surgery, &c._ 5 5 James Brown, Esq. _Leeds_ 1 1 J. Brown, M.D. _Islington_ 1 1 Mr. Brown 1 1 ------Bryant, Esq. _Lynn Regis, Surgeon_ 1 1 Dr. Buchan 1 1 Rev. Gilbert Buchanan, LL.D. _Rector of Woodmanstow, Surry_ 1 1 Mr. Buchenson, _Surgeon_ 1 1 Buckingham Book Society 1 1 George Buckle, Esq. 2 2 William Buckley, Esq. 1 1 Mr. Henry Budd 1 1 Mr. John Buddle 1 1 Mr. J. Buncomb, _Taunton, Somerset._ 1 1 Mr. A. S. Burkitt, _Chemist_ 3 5 6 Charles Burney, LL.D. F.R.S. F.A.S. P.R.I. _Greenwich_ 1 1 Robert Burns, Esq. 1 1 Mrs. Butts 1 1 C. Sir John Chetwode, Bart. 1 1 Henry Cavendish, Esq. F.R.S. F.A.S. P.R.I. 10 10 Thomas Coutts, Esq. P.R.I. 10 10 Mr. John Callow 1 1 Dr. Alexander Campbell, _Secretary to the Medical Board, Calcutta_ 1 1 Dr. Campbell, _Lancaster_ 1 1 Colonel James Campbell 1 1 Mr. Card 1 1 Anthony Carlisle, Esq. F.L.S. 1 1 Mr. John Carpenter, Senr. _Lyme_ J. C. Carpue, Esq. 2 2 George Carr, Esq. _St. Petersburg_ 1 11 6 Thomas W. Carr, Esq. P.R.I. 1 1 Mr. W. Cary 1 1 William Cass, Esq. 1 1 Dr. Cassels, _Lancaster_ 1 1 D. Cassidy, Esq. 1 1 John Cates, Esq. 1 1 H. Cayley, Esq. _St. Petersburg_ 1 11 6 William Chamberlain, Esq. 1 1 L. B. Chateauneauf, Esq. 1 1 Chester Public Library 1 1 Henry Chevalier, Esq. F.L.S. 2 2 Mrs. Chevalier 1 1 James Chew, M.D. _Blackburn_ 1 1 Mr. Christian, _Attorney_ 1 1 ------Clapham, Esq. _Thorney Abbey, Surgeon_ 1 1 John Clarke, Esq. 1 1 J. Calvert Clarke, Esq. 5 5 Ralph Clarke, Esq. 1 1 Richard Hall Clarke, Esq. _Devon._ 1 1 Mr. John Clay 1 1 S. P. Cockerell, Esq. P.R.I. 2 2 Miss Codrington 2 2 Mr. John Cohen 1 1 Mr. Collier 1 1 Mr. Coltman, _Surgeon_ 2 2 Mr. Colton 1 1 Mr. Cooke 1 1 B. Coombe, Esq. 2 2 Astley Cooper, Esq. F.R.S. 5 5 Rev. Stuart Corbett Adam Cottam, Esq. _Whalley, near Blackburn_ 1 1 Mr. Cotter, _Godstone, Surry_ 1 1 Mr. Cotter 1 1 John Cowan, Esq. 1 1 Theodore Cox, Esq. 2 2 John Craig, Esq. _Glasgow_ 1 1 Mr. Cregg 1 1 Thomas Creser, Esq. 1 1 William Cresswell, Esq. 1 1 Alexander Crichton, M.D. F.R.S. F.L.S. 2 2 Mr. Crigg 1 1 George Crooke, Esq. Hugh Cross, Esq. 2 2 C. Cuppage, Esq. 1 1 Mr. William Cuppage 2 2 James Currie, M.D. F.R.S. _Physician to Guy's Hospital_ 2 2 ------Currie, M.D. 5 5 ------Cuthbert 1 11 6 Mr. John Cuthbertson 1 11 6 D. Sir George Duckett, Bart. P.R.I. 1 1 Peter Denys, Esq. P.R.I. 10 10 Lady C. Denys 5 5 George William Denys, Esq. P.R.I. 5 5 David Dale, Esq. 5 5 J. P. Dale, Esq. 5 5 Thomas Dale, M.D. 1 1 Mr. Daniel Dale 5 5 Mr. Daltera, _Attorney_ 1 1 Mr. Darbyshire 1 1 Mr. Davie, _St Thomas's Hospital_ 1 1 Dr. Davies, _Bath_ 1 1 Dr. Davison, _Harewood_ Humphry Davy, Esq. F.R.S. 5 5 Mr. Joseph Dawson 1 1 Thomas Dawson, Esq. _Surgeon_ 1 1 Mr. Thomas Dawson 1 1 Mr. Dawson 2 2 Thomas Day, Esq. P.R.I. 5 5 Miss Day 2 2 Mrs. Delamore 1 1 Thomas Demson, Esq. 1 1 R. Dennison, M.D. and F.A.S. 2 2 Osbert Denton, Esq. _Chelsea_ 10 0 Mrs. Denton 10 0 Miss Denton 5 0 Mr. Benjamin Devaynes 1 1 N. Devy, Esq. 1 1 Charles Dibdin, Esq. 5 5 William Dick, Esq. 1 1 W. Dickson, LL.D. _Clipstone St._ 2 2 Charles Dilly, Esq. 2 2 Mr. William Dinsley, _Leeds_ 1 1 ------Doig, Esq. 1 1 Mr. Doig 1 1 George Dominicus, Esq. 2 2 Rev. Thomas Donald, _Anthorne, Cumberland_ 1 1 Andrew Douglas, Esq. F.R.S. P.R.I. 5 5 Mr. James Dove 1 1 Henry Downer, Esq. 1 1 Mr. Drewe 1 1 F. Duboulay, Esq. 1 1 Dr. Andrew Duncan, _Edinburgh_ Dr. Andrew Duncan, Jun. _Do._ Mrs. Dunlop, _Hammersmith_ 1 1 Miss Dunlop, _Hammersmith_ 1 1 James Dupre, Esq. P.R.I. 1 1 E. Marquis of Exeter, F.R.S. F.A.S. 5 5 Marchioness of Exeter 5 5 The Earl of Egremont, F.R.S. F.A.S. P.R.I. 10 10 Sir H. C. Englefield, Bart. F.R.S. F.A.S. P.R.I. 3 3 Sir James Earle 2 2 Hon. William Elphinstone 1 1 R. G. Ealand, Esq. 1 1 Willis Earle, Esq. 2 2 ------Eccles, Esq. _Clithero_ 1 1 D. B. Plantagenet Eccleston, Esq. 1 1 Library of the University of Edinburgh Mr. Edmondson, _Surgeon, Lancaster_ 1 1 Mr. Richard Elgar 1 1 George Ellis, Esq. F.R.S. F.A.S. P.R.I. 1 1 John Fullerton Elphinstone, Esq. _East Lodge, Enfield_ 1 1 Alexander Erskine, Esq. F.L.S. 1 1 George Erving, Esq. 1 1 John Esdaile. Esq. P.R.I. 1 1 Isaac Espinasse, Esq. 2 2 William Etty, Esq. 1 1 Mr. Evans 1 1 F Col. the Hon. T. W. Fermor, P.R.I. 10 10 James Fallofeild, Esq. P.R.I. 2 2 Vere Fane, Esq. 1 1 Thomas Farquhar, Esq. 1 1 Robert Farquhar, Esq. _Rochester_ 1 1 Mr. Faulder 1 1 W. Fawkes, Esq. _Farnley, near Leeds_ 3 3 John Feltham, Esq. 2 2 Richard Firmin, Esq. 3 3 Mr. M. Fitzgerald 1 1 Lewis Flannagan, Esq. 2 2 Arch. Fletcher, _Advocate, Glasgow_ 2 2 Caleb Fletcher, Esq. 2 2 Mr. Benjamin Flockton ------Forbes, Esq. 1 1 Henry Fock, Esq. _St. Petersburg_ 1 11 6 Mr. Ford, _Pimlico_ 1 1 ------Ford, Esq. 2 2 R. Forrester, Esq. _St. Petersburg_ 1 11 6 B. M. Forster, Esq. 1 1 Rev. Edward Forster, F.R.S. F.A.S. P.R.I. 1 1 Thomas Foster, Esq. 1 1 Thomas Fothergill, Esq. 2 2 John Foulks, Esq. 2 2 Joseph Fox, Esq. 2 2 Rev. M. Foxcroft 1 1 James Fraser, Esq. P.R.I. 1 1 F. Freelong, Esq. 1 1 ------French, Esq. 1 1 A Friend 2 2 A friend, W. M. 1 1 A friend, J. C. 1 1 A friend, T. K. 2 2 A friend, E. 4 4 A friend, T. 10 0 A friend, J. G. 5 5 A friend, A. 2 2 A friend, R. W. by Mr. Lawson 1 1 A friend, W. W. 1 1 A friend, I. A. W. 1 1 A friend, I. S. 1 1 A friend, A. B. 2 2 A friend, I. B. 5 5 A friend, W. D. 2 2 A friend, D. D. 2 2 A friend, J. L. Esq. 3 3 A friend, E. A. 1 1 A friend, I. S. 1 1 A friend, I. B. 1 1 A friend, M. W. 1 1 A friend, M. B. 5 0 A friend, I. A. W. 1 1 A friend, E. D. 1 1 A friend, J. D. 1 1 A friend, J. P. D. 1 1 A friend, S. B. D. 4 4 A friend, S. D. 5 5 A friend, Mr. B. 1 1 A friend, Mr. B. 1 1 A friend, S. E. D. 1 1 A friend, S. E. D. 1 1 A friend, S. M. D. 1 1 A friend, I. T. by Mr. I. J. Armiger 1 1 A friend, by Dr. Batty 3 3 A friend, I. H. D. by Dr. Batty 3 3 A friend, by D. Braithwaite, Esq. 3 3 A friend, by Miss Braithwaite 2 2 A friend, by Mr. Gear 1 1 A friend, H. L. by Mr. Thomas 1 1 A friend, S. H. by Mr. Lawson 2 2 A friend, by Mr. Rathbone 5 5 Edmund Fry, M.D. 1 1 G Sir James Whalley Gardiner, Bart. _Clerk Hill, near Blackburn_ 3 3 Mr. William Gaitskell 3 3 Peter Garforth, Esq. 5 5 John Gaythorne, Esq. 2 2 Robert Gear, Esq. 2 2 Do. for a friend, _no Book_ 1 1 John Geddes, Esq. 2 2 James Gerard, Esq. 3 3 Mr. Robert Gibson 2 2 Mr. W. Gilbert, _Optician_ 2 2 Collin Gillespie, Esq. 1 1 William Gillespie, Esq. 5 5 Robert Gillespie, Esq. 1 1 Thomas Gisborne, M.D. F.R.S. 1 1 Henry Glossop, Esq. _Cambridge_ 2 2 Mrs. Gooch 1 1 ------Good, Esq. 1 1 Mr. Good 1 1 Mr. Alexander Gordon, _Surgeon_ 1 1 Mr. Alexander Caudleraig Gordon, _Edinburgh_ 1 1 Mrs. Maxwell Gordon, _Edinburgh_ 2 2 Thomas T. Gorsuch, Esq. 1 1 Mr. Samuel Gosnell, _Printer_ 1 1 Joseph Gough, Esq. 1 1 Archibald Graham, Esq. _Glasgow_ 1 1 Robert Graham, Esq. 1 1 Mrs. Henry Grant 2 2 Alex. Grant, Esq. _St. Petersburg_ 1 11 6 Edward Whitaker Gray, M.D. Sec. R.S. 1 1 R. Greaves, M.D. _Reading, Berks._ 2 2 Mr. Griffenhof, _Hampton_ 1 1 Thomas Green, Esq. 3 3 Mrs. Green 2 2 ------Greenwood, Esq. _Lancaster, Surgeon_ 1 1 John Grenfell, Esq. _Chelsea_ 1 1 Mr. Griffin 1 1 T. Grimston, Esq. _Kilnwick, York._ 1 1 Henry Grimston, Esq. F.L.S. 1 1 John Guthrie, Esq. 2 2 H Sir John Cox Hippisley, Bart. F.R.S. F.A.S. P.R.I. 5 5 Hon. Mr. Justice Heath, P.R.I. 1 1 Messrs. Hoare 21 0 Mr. Hadwen, _Lancaster_ 1 1 G. H. C. Hahn, Esq. _Wimbledon_ 1 1 Samuel Hailstone, Esq. 1 1 John Hale, Esq. P.R.I. 2 2 Mr. T. Hall 2 2 Mr. Halliday, _Everton, near Liverpool_ 1 1 Dr. James Hamilton, _Professor of Midwifery, University, Edinburgh_ Mr. John Hamilton 1 1 Colonel Hamilton, _His Majesty's Consul, Norfolk, Virginia_ 5 0 G. H. Hancock, Esq. 1 1 Mr. Hankey 5 5 Mr. John Harding 1 1 Robert Hardy, Esq. _Whalley, near Blackburn, Surgeon_ 1 1 Mr. John Hardy 1 1 Rev. Richard Harrington, _Hayley, Worcestershire_ 1 1 Rev. Robert Harris, _Preston_ 1 1 J. 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Jackson, Esq. _St. Petersburg_ 1 11 6 Mr. Jackson, _Lancaster_ 1 1 Miss Sarah Jackson 1 1 William James, Esq. 1 1 Thomas I'anson, Esq. 2 2 ------Jaques, M.D. _Harrowgate_ 2 2 ------Jardine, M.D. 2 2 George Jeffery, Esq. 1 1 Edward Jenner, M.D. F.R.S. F.L.S. 10 10 Edward Jenings, Esq. _Kensington_ 1 1 William Ingham, Esq. _Newcastle upon Tyne_ 2 2 Rt. Innes, Esq. _Newcastle upon Tyne_ 1 1 Edward Johnson, Esq. _Mile End_ 1 1 Christopher Johnson, Esq. 1 1 R. Johnson, Esq. 1 1 ------Jones, Esq. _Chelsea_ 1 1 W. Jones, Esq. _St. Petersburg_ 1 11 6 Thomas Jones, Esq. _Llandisillio Hall, Oswestry_ 1 1 Mr. John Jones, _Surgeon_ 2 2 Stephen Jones, Esq. 1 1 Gibbs Walker Jordan, Esq. F.R.S. 3 3 Major Jourdan 1 1 Rev. J. Joyce 1 1 Thomas Irving, Esq. 2 2 Thomas Irwin, Esq. 1 1 Mr. Ives, _Surgeon, Chertsey_ K The Hon. George Knox, F.R.S. 10 10 Frederick Kanmacher, Esq. P.R.I. F.L.S. 1 1 Mr. B. A. Keck, _Leeds_ Miss Keene 2 2 Mr. P. Kelly 1 1 Dr. E. Kentish, _Bristol_ Mr. Jonathan Key 1 1 T. 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6970	----	THE HISTORY OF A MOUTHFUL OF BREAD: And Its Effect on the Organization of Men and Animals. BY JEAN MACÉ. Translated Prom the Eighth French Edition, By Mrs. Alfred Gatty. EXTRACTS FROM THE PREFACE TO THE ENGLISH EDITION. The volume of which the following pages are a translation, has been adopted by the _University Commission at Paris_ among their prize books, and has reached an eighth edition. Perhaps these facts speak sufficiently in its favor; but as translator, and to some extent editor, I wish to add my testimony to the great charm as well as merit of the little work. I sat down to it, I must own, with no special predilection in favor of the subject as a suitable one for young people; but in the course of the labor have become a thorough convert to the author's views that such a study--perhaps I ought to add, so pursued as he has enabled it to be--is likely to prove a most useful and most desirable one. The precise age at which the interest of a young mind can be turned towards this practical branch of natural history is an open question, and not worth disputing about. It may vary even in different individuals. The letters are addressed to a _child_--in the original even to a _little girl_--and most undoubtedly, as the book stands, it is fit for any child's perusal who can find amusement in its pages: while to the rather older readers, of whom I trust there will be a great many, I will venture to say that the advantage they will gain in the subject having been so treated as to be brought within the comprehension and adapted to the tastes of a child, is pretty nearly incalculable. The quaintness and drollery of the illustrations with which difficult scientific facts are set forth will provoke many a smile, no doubt, and in some young people perhaps a tendency to feel themselves treated _babyishly_; but if in the course of the babyish treatment they find themselves almost unexpectedly becoming masters of an amount of valuable information on very difficult subjects, they will have nothing to complain of. Let such young readers refer to even a popular Encyclopaedia for an insight into any of the subjects of the twenty-eight chapters of this volume--"The Heart," "The Lungs," "The Stomach," "Atmospheric Pressure,"--no matter which, and see how much they can understand of it without an amount of preliminary instruction which would require half-a-year's study, and they will then thoroughly appreciate the quite marvellous ingenuity and beautiful skill with which M. Macé has brought the great leading anatomical and physical facts of life out of the depths of scientific learning, and made them literally comprehensible by a child. * * * * * There is one point (independent of the scientific teaching) and that, happily, the only really important one, in which the English translator has had no change to make or desire. The religious teaching of the book is unexceptionable. There is no strained introduction of the subject, but there is throughout the volume an acknowledgment of the Great Creator of this marvellous work of the human frame, of the daily and hourly gratitude we owe to Him, and of the utter impossibility of our tracing out half his wonders, even in the things nearest to our senses, and most constantly subject to observation. M. Macé will help, and not hinder the humility with which the Christian naturalist lifts one veil only to recognise another beyond. It will be satisfactory to any one who may be inclined to wonder how a lady can feel sure of having correctly translated the various scientific and anatomical statements contained in the volume, to know that the whole has been submitted to the careful revision of a medical friend, to whom I have reason to be very grateful for valuable explanations and corrections whenever they were necessary. In the same way the chapter on "Atmospheric Pressure," where, owing to the difference between French and English weights and measures, several alterations of illustrations, etc., had to be made, has received similar kind offices from the hands of a competent mathematician. * * * * * MARGARET GATTY. Ecclesfield, June, 1864. NOTE TO THE AMERICAN EDITION. In May '66, the seventeenth edition of this work was on sale in Paris. The date of Mrs. Gatty's preface, it will be observed, is June '64, and at that time, the eighth French edition only had been reached. That it should be a popular book and command large sale wherever it is known, will not surprise any one who reads it: the only remarkable circumstance about it is, that it should not have been republished here long ere this. Even this may probably be accounted for, on the supposition that the title under which the translation was published in England, was so unmeaning--conveying not the slightest idea of the contents of the book--that none of our publishers even ventured to hand it over to their "readers" to examine. The author's title, _The History of a Mouthful of Bread_, while falling far short of giving a clear notion of the entire scope of the work, is shockingly diluted and meaningless, when translated _The History of a Bit of Bread!_ To the translation of Mrs. Gatty, which is in the main an excellent one, for she has generally seized upon the idea of the author and rendered it with singular felicity, it may be very properly objected that she has taken some liberties with the text when there was any conflict of opinion between herself and her author, and has given her own ideas instead of his, which is, probably, what she refers to when she calls herself "to some extent editor." The reader of this edition will, in all these cases, find the thought of the author and not that of his translator; for the reason that a careful examination of the original has convinced the publisher that in every instance the author was to be preferred to the translator, to say nothing of the right an author may have to be faithfully translated. Besides making these restorations, the copy from which this edition was printed has been carefully compared with the last edition of the author and a vast number of corrections made, and in its present shape it is respectfully submitted and dedicated to every one (whose name is legion, of course) who numbers among his young friends a "_my dear child_" to present it to. CONTENTS. I.--INTRODUCTION FIRST PART MAN. II.--THE HAND III.--THE TONGUE IV.--THE TEETH V.--THE TEETH (_continued_) VI.--THE TEETH (_continued_) VII.--THE THROAT VIII.--THE STOMACH IX.--THE STOMACH (_continued_) X.--THE INTESTINAL CANAL XI.--THE LIVER XII.--THE CHYLE XIII.--THE HEART XIV.--THE ARTERIES XV.--THE NOURISHMENT OF THE ORGANS XVI.--THE ORGANS XVII.--ARTERIAL AND VENOUS BLOOD XVIII.--ATMOSPHERIC PRESSURE XIX.--THE ACTION OF THE LUNGS XX.--CARBON AND OXYGEN XXI.--COMBUSTION XXII.--ANIMAL HEAT XXIII.--ACTION OF THE BLOOD UPON THE ORGANS XXIV.--THE WORK OF THE ORGANS XXV.--CARBONIC ACID XXVI.--ALIMENTS OF COMBUSTION XXVII.--ALIMENTS OF NUTRITION (_continued_)--NITROGEN OR AZOTE XXVIII.--COMPOSITION OF THE BLOOD SECOND PART. ANIMALS. XXIX.--CLASSIFICATION OF ANIMALS XXX.--MAMMALIA (_Mammals_) XXXI.--MAMMALIA. (_Mammals_)--_continued_ XXXII.--MAMMALIA--_continued_ XXXIII.--MAMMALIA--_continued_ XXXIV.--AVES. (_Birds_) XXXV.--REPTILIA. (_Reptiles_) XXXVI.--PISCES. (_Fishes_) XXXVII.--INSECTA. (_Insects_) XXXVIII.--CRUSTACEA--MOLLUSKA. (_Crustaceans and Mollusks_) XXXIX.--VERMES--ZOOPHYTA. (_Worms and Zoophytes_) XL.--THE NOURISHMENT OF PLANTS CONCLUSION I. INTRODUCTION. I am going to tell you, my dear child, something of the life and nature of men and animals, believing the information may be of use to you in after-life, besides being an amusement to you now. Of course, I shall have to explain to you a great many particulars which are generally considered very difficult to understand, and which are not always taught even to grown-up people. But if we work together, and between us succeed in getting them clearly into your head, it will be a great triumph to me, and you will find out that the science of learned men is more entertaining for little girls, as well as more comprehensible, than it is sometimes supposed to be. Moreover, you will be in advance of your years, as it were, and one day may be astonished to find that you had mastered in childhood, almost as a mere amusement, some of the first principles of anatomy, chemistry, and several other of the physical sciences, as well as having attained to some knowledge of natural history generally. I begin at once, then, with the _History of a Mouthful of Bread_, although I am aware you may be tempted to exclaim, that if I am going to talk only about that, I may save myself the trouble. You know all about it, you say, as well as I do, and need not surely be told how to chew a bit of bread-and-butter! Well, but you must let me begin at the very beginning with you, and you have no notion what an incredible number of facts will be found to be connected with this chewing of a piece of bread. A big book might be written about them, were all the details to be entered into. First and foremost--Have you ever asked yourself _why_ people eat? You laugh at such a ridiculous question. "Why do people eat? Why, because there are bonbons, and cakes, and gingerbread, and sweetmeats, and fruit, and all manner of things good to eat." Very well, that is a very good reason, no doubt, and you may think that no other is wanted. If there were nothing but soup in the world, indeed, the case would be different. There might be some excuse then for making the inquiry. Now, then, let us suppose for once that there _is_ nothing in the world to eat but soup; and it is true that there are plenty of poor little children for whom there is nothing else, but who go on eating nevertheless, and with a very good appetite, too, I assure you, as their parents know but too well very often. Why do people eat, then, even when they have nothing to eat but soup? This is what I am going to tell you, if you do not already know. The other day, when your mamma said that your frock "had grown" too short, and that you could not go out visiting till we had given you another with longer sleeves and waist, what was the real cause of this necessity? What a droll question, you say, and you answer--"Because I had grown, of course." To which I say "of course," too; for undoubtedly it was you who had outgrown your frock. But then I must push the question further, and ask--How had you grown? Now you are puzzled. Nobody had been to your bed and pulled out your arms or your legs as you lay asleep. Nobody had pieced a bit on at the elbow or the knee, as people slip in a new leaf to a table when there is going to be a larger party than usual at dinner. How was it, then, that the sleeves no longer came down to your wrists, or that the body only reached your knees? Nothing grows larger without being added to, any more than anything gets smaller without having lost something; you may lay that down as a rule, once for all. If, therefore, nothing was added to you from without, something must have been added to you from within. Some sly goblin, as it were, must have been cramming into your frame whatever increase it has made in arms, legs, or anything else. And who, do you think, this sly goblin is? Why, my dear, it is _yourself!_ Ay! Bethink you, now, of all the bread-and-butter, and bonbons, and gingerbread, and cakes, and sweetmeats, and even soup and plain food (the soup and plain food being the most useful of all) which you have been sending, day by day, for some time past, down what we used to call "the red lane," into the little gulf below. What do you think became of them when they got there? Well, they set to work at once, without asking your leave, to transform themselves into something else; and gliding cunningly into all the holes and corners of your body, became there, each as best he might, bones, flesh, blood, etc., etc. Touch yourself where you will, it is upon these things you lay your hand, though, of course, without recognizing them, for the transformation is perfect and complete. And it is the same with everybody. Look at your little pink nails, which push out further and further every morning; examine the tips of your beautiful fair hair, which gets longer and longer by degrees; coming out from your head as grass springs up from the earth; feel the firm corners of your second teeth, which are gradually succeeding those which came to you in infancy; you have _eaten_ all these things, and that no long time ago. Nor are you children the only creatures who are busy in this way. There is your kitten, for instance, who a few months ago was only a tiny bit of fur, but is now turning gradually into a grown-up cat. It is her daily food which is daily becoming a cat inside her--her saucers of milk now, and very soon her mice, all serve to the same end. The large ox, too, of whom you are so much afraid, because you cannot as yet be persuaded what a good-natured beast he really is, and how unlikely to do any harm to children who do none to him--that large ox began life as a small calf, and it is the grass which he has been eating for some time past which has transformed him into the huge mass of flesh you now see, and which by-and-by will be eaten by man, to become man's flesh in the same manner. But, further, still: Even the forest trees, which grow so high and spread so wide, were at first no bigger than your little finger, and all the grandeur and size you now look upon, they have taken in by the process of eating. "What, _do trees eat?_" you ask. Verily, do they; and they are, by no means, the least greedy of eaters, for they eat day and night without ceasing. Not, as you may suppose, that they crunch bonbons, or anything else as you do; nor is the process with them precisely the same as with you. Yet you will be surprised hereafter, I assure you, to find how many points of resemblance exist between them and us in this matter. But we will speak further of this presently. Now, I think you must allow that there are few fairytales more marvellous than this history of bread and meat turning into little boys and girls, milk and mice turning into cats, and grass into oxen! And I call it a _history_, observe, because it is a transformation that never happens suddenly, but by degrees, as time goes on. Now, then, for the explanation. You have heard, I dare say, of those wonderful spinning-machines which take in at one end a mass of raw cotton, very like what you see in wadding, and give out at the other a roll of fine calico, all folded and packed up ready to be delivered to the tradespeople. Well, you have within you, a machine even more ingenious than that, which receives from you all the bread-and-butter and other sorts of food you choose to put into it, and returns it to you changed into the nails, hair, bones and flesh we have been talking about, and many other things besides; for there are quantities of things in your body, all different from each other, which you are manufacturing in this manner all day long, without knowing anything about it. And a very fortunate thing this is for you: for I do not know what would become of you if you had to be thinking from morning to night of all that requires to be done in your body, as your mother has to look after and remember all that has to be done in the house. Just think what a relief it would be to her to possess a machine which should sweep the rooms, cook the dinners, wash the plates, mend torn clothes, and keep watch over everything without giving her any trouble; and, moreover, make no more noise or fuss than yours does, which has been working away ever since you were born without your ever troubling your head about it, or probably even knowing of its existence! Just think of this and be thankful. But do not fancy you are the only possessor of a magical machine of this sort. Your kitten has one also, and the ox we were speaking of, and all other living creatures. And theirs render the same service to them that yours does to you, and much in the same way; for all these machines are made after one model, though with certain variations adapted to the differences in each animal. And, as you will see by-and-by, these variations exactly correspond with the different sort of work that has to be done in each particular case. For instance, where the machine has grass to act upon, as in the ox, it is differently constructed from that in the cat which has to deal with meat and mice. In the same way in our manufactories, though all the spinning-machines are made upon one model, there is one particular arrangement for those which spin cotton, another for those which spin wool, another for flax, and so on. But, further: You have possibly noticed already, without being told, that all animals are not of equal value; or, at least, to use a better expression, they have not all had the same advantages bestowed on them. The dog, for instance, that loving and intelligent companion, who almost reads your thoughts in your eyes, and is as affectionate and obedient to his master as it were to be wished all children were to their parents--this dog is, as you must own, very superior, in all ways, to the frog, with its large goggle eyes and clammy body, hiding itself in the water as soon as you come near it. But again, the frog, which can come and go as it likes, is decidedly superior to the oyster, which has neither head nor limbs, and lives all alone, glued into a shell, in a sort of perpetual imprisonment. Now the machine I have been telling you about is found in the oyster and in the frog as well as in the dog, only it is less complicated, and therefore less perfect in the oyster than in the frog; and less perfect again in the frog than in the dog; for as we descend in the scale of animals we find it becoming less and less elaborate--losing here one of its parts, there another, but nevertheless remaining still the same machine to all intents and purposes; though by the time it has reached its lowest condition of structure we should hardly be able to recognize it again, if we had not watched it through all its gradations of form, and escorted it, as it were, from stage to stage. Let me make this clear to you by a comparison. You know the lamp which is lit every evening on the drawing-room table, and around which you all assemble to work or read. Take off first the shade, which throws the light on your book--then the glass which prevents it smoking--then the little chimney which holds the wick and drives the air into the flame to make it burn brightly. Then take away the screw, which sends the wick up and down; undo the pieces one by one, until none remain but those absolutely necessary to having a light at all--namely, the receptacle for the oil and the floating wick which consumes it. Now if any one should come in and hear you say, "Look at my lamp," what would he reply? He would most likely ask at once, "What lamp?"--for there would be very little resemblance to a lamp in that mere ghost of one before him. But to you, who have seen the different parts removed one after another, that wick soaked in oil (let your friend shake his head about it as he pleases) will still be the lamp to you, however divested of much that made it once so perfect, and however dimly it may shine in consequence. And this is exactly what happens when the machine we are discussing is examined in the different grades of animals. The ignoramus who has not followed it through its changes and reductions cannot recognize it when it is presented to him in its lowest condition; but any one who has carefully observed it throughout, knows that it is, in point of fact, the same machine still. This, then, is what we are now going to look at together, my dear little girl. We will study first, piece by piece, the exquisite machine within ourselves, which is of such unceasing use to us as long as we do not give it more than a proper share of work to perform. Do you understand? We will see what becomes of the mouthful of bread which you place so coolly between your teeth, as if when that was done nothing further remained to be thought about. We will trace it in its passage through every part of the machine, from beginning to end. It will therefore be simply only the _History of a Mouthful of Bread_ I am telling you, even while I seem to be talking of other matters; for to make that comprehensible I shall have to enter into a good many explanations. And when you have thoroughly got to understand the history of what you eat yourself, we will look a little into the history of what other animals eat, beginning by those most like ourselves, and going on to the rest in regular succession downwards. And while we are on the subject, I will say a word or two on the way in which vegetables eat, for, as you remember, I have stated that they do eat also. Do you think this is likely to interest you, and be worth the trouble of some thought and attention? Perhaps you may tell me it sounds very tedious, and like making a great fuss about a trifle; that you have all your life eaten mouthfuls of bread without troubling yourself as to what became of them, and yet have not been stopped growing by your ignorance, any more than the little cat, who knows no more how it happens than you do. True, my dear; but the cat is only a little cat, and you are a little girl. Up to the present moment you and she have known, one as much as the other on this subject, and on that point you have therefore had no superiority over her. But she will never trouble herself about it, and will always remain a little cat. You, on the contrary, are intended by God to become something more in intelligence than you are now, and it is by learning more than the cat that you will rise above her in this respect. To learn, is the duty of all men, not only for the pleasure of curiosity and the vanity of being called learned, but because in proportion to what we learn we approach nearer to the destiny which God has appointed to man, and when we walk obediently in the path which God himself has marked out for us, we necessarily become better. It is sometimes said to grown-up people, that it is never too late to learn. To children one may say that it is never too early to learn. And among the things which they may learn, those which I want now to teach you have the double merit of being, in the first place amusing, and afterwards, and above all, calculated to accustom you to think of God, by causing you to observe the wonders which He has done. Sure am I that when you know them you will not fail to admire them; moreover I promise your mother that you will be all the better, as well as wiser, for the study. FIRST PART.--MAN. LETTER II. THE HAND. At the foot of the mountains, from whence I write to you, my dear child, when we want to show the country to a stranger, we commence by making him climb one of the heights, whence he may take in at a glance the whole landscape below, all the woods and villages scattered over the plain, even up to the blue line of the Rhine, which stretches out to the distant horizon. After this he will easily find his way about. It is to the top of a mountain equally useful that I have just led you. It has cost you some trouble to climb with me. You have had to keep your eyes very wide open that you might see to the end of the road we had to go together. Now then, let us come down and view the country in detail. Then we shall go as if we were on wheels. And now let us begin at the beginning: Well, doubtless, as the subject is eating, you will expect me to begin with the mouth. Wait a moment; there is something else first. But you are so accustomed to make use of it, that you have never given it a thought, I dare say. It is not enough merely that one should have a mouth; we must be able to put what we want within it. What would you do at dinner, for instance, if you had no hands? The hand is then the first thing to be considered. I shall not give you a description of it; you know what it is like. But what, perhaps, you do not know, because you have never thought about it, is, the reason why your hand is a more convenient, and consequently more perfect, instrument than a cat's paw, for instance, which yet answers a similar purpose, for it helps the cat to catch mice. Among your five fingers there is one which is called the thumb, which stands out on one side quite apart from the others. Look at it with respect; it is to these two little bones, covered over with a little flesh, that man owes part of his physical superiority to other animals. It is one of his best servants, one of the noblest of God's gifts to him. Without the thumb three-fourths (at least) of human arts would yet have to be invented; and to begin with, the art not only of carrying the contents of one's plate to one's mouth, but of filling the plate (a very important question in another way) would, but for the thumb, have had difficulties to surmount of which you can form no idea. Have you noticed that when you want to take hold of anything (a piece of bread, we will say, as we are on the subject of eating), have you noticed that it is always the thumb who puts himself forward, and that he is always on one side by himself, whilst the rest of the fingers are on the other? If the thumb is not helping, nothing remains in your hand, and you don't know what to do with it. Try, by way of experiment, to carry your spoon to your mouth without putting your thumb to it, and you will see what a long time it will take you to get through a poor little plateful of broth. The thumb is placed in such a manner on your hand that it can face each of the other fingers one after another, or all together, as you please; and by this we are enabled to grasp, as if with a pair of pincers, whatever object, whether large or small. Our hands owe their perfection of usefulness to this happy arrangement, which has been bestowed on no other animal, except the monkey, our nearest neighbor. I may even add, while we are about it, that it is this which distinguishes the hand from a paw or a foot. Our feet, which have other things to do than to pick up apples or lay hold of a fork, our feet have also each five fingers, but the largest cannot face the others; it is not a thumb, therefore, and it is because of this that our feet are not hands. Now the monkey has thumbs on the four members corresponding to our arms and legs, and thus we may say that he has hands at the end of his legs as well as of his arms. Nevertheless, he is not on that account better off than we are, but quite the contrary. I will explain this to you presently. To return to our subject. You see that it was necessary, before saying anything about the mouth, to consider the hand, which is the mouth's purveyor. Before the cook lights the fires the maid must go to market, must she not? And it is a very valuable maid that we have here: what would become of us without her? If we were in the habit of giving thought to everything, we should never even gather a nut without being grateful to the Providence which has provided us with the thumb, by means of which we are able to do it so easily. But however well I may have expressed it, I am by no means sure, after all, that I have succeeded in showing you clearly, how absolutely necessary our hand is to us in eating, and why it has the honor to stand at the beginning of the history of what we eat. It still appears to you, I suspect, that even if you were to lose the use of your hands you would not, for all that, let yourself die of hunger. This is because you have not attended to another circumstance, which nevertheless demands your notice--namely, that from one end of the world to the other, quantities of hands are being employed in providing you with the wherewithal to eat. To go on further: Have you any idea how many hands have been put in motion merely to enable you to have your coffee and roll in the morning? What a number, to be sure, over this cup of coffee (which is a trifle in comparison with the other food you will consume in the course of the day); from the hand of the negro who gathered the coffee crop to that of the cook who ground the berries, to say nothing of the hand of the sailor who guided the ship which bore them to our shores. Again, from the hand of the laborer who sowed the corn, and that of the miller who ground it into flour, to the hand of the baker who made it into a roll. Then the hand of the farmer's wife who milked the cow, and the hand of the refiner who made the sugar; to say nothing of the many others who prepared his work for him, and I know not how many more. How would it be, then, if I were to amuse myself by counting up all the hands that are wanted to furnish-- The sugar-refiner's manufactory, The milkmaid's shed, The baker's oven, The miller's mill, The laborer's plough, The sailor's ship? And even now is there nothing we have forgotten? Ah, yes! the most important of all the hands to you;--the hand which brings together for your benefit the fruits of the labor of all the others--the hand of your dear mother, always active, always ready, that hand which so often acts as yours when your own is awkward or idle. Now, then, you see how you might really manage to do without those two comparatively helpless little paws of yours (although there is a thumb to each), without suffering too much for want of food. With such an army of hands at work, in every way, to furnish provision for that little mouth, there would not be much danger. But cut off your cat's fore paws--oh dear! what am I saying? Suppose, rather, that she has not got any, and then count how many mice she will catch in a day. The milk you give her is another matter, remember. Like your cup of coffee, that is provided for her by others. Believe me, if you were suddenly left all alone in a wood, like those pretty squirrels who nibble hazel-nuts so daintily, you would soon discover, from being thus thrown upon your own resources, that the mouth is not the only thing required for eating, and that whether it be a paw or a hand, there must always be a servant to go to market for Mr. Mouth, and to provide him with food. Happily, we are not driven to this extremity. We take hold of our coffee-biscuit between the thumb and forefinger, and behold it is on its road--Open the mouth, and it is soon done! But before we begin to chew, let us stop to consider a little. The mouth is the door at which everything enters. Now, to every well-kept door there is a doorkeeper, or porter. And what is the office of a well-instructed porter? Well, he asks the people that present themselves, who they are, and what they have come for; and if he does not like their appearance, he refuses them admittance. We too, then, to be complete, need a porter of this sort in our mouths, and I am happy to say we have one accordingly. I wonder whether you know him? You look at me quite aghast! Oh, ungrateful child, not to know your dearest friend! As a punishment, I shall not tell you who he is to-day. I will give you till to-morrow to think about it. Meanwhile, as I have a little time left, I will say one word more about what we are going to look at together. It would hardly be worth while to tell you this pretty story which we have begun, if from time to time we were not to extract a moral from it. And what is the moral of our history to-day? It has more than one. In the first place it teaches you, if you never knew it before, that you are under great obligations to other people, indeed to almost everybody, and most of all perhaps to people whom you may be tempted to look down upon. This laborer, with his coarse smock-frock and heavy shoes, whom you are so ready to ridicule, is the very person who, with his rough hand, has been the means of procuring for you half the good things you eat. That workman, with turned-up sleeves, whose dirty black fingers you are afraid of touching, has very likely blackened and dirtied them in your service. You owe great respect to all these people, I assure you, for they all work for you. Do not, then, go and fancy yourself of great consequence among them--you who are of no use in any way at present, who want everybody's help yourself, but as yet can help nobody. Not that I mean to reproach you by saying this. Your turn has not come yet, and everybody began like you originally. But I do wish to impress upon you that you must prepare yourself to become some day useful to others, so that you may pay back the debts which you are now contracting. Every time you look at your little hand, remember that you have its education to accomplish, its debts of honor to repay, and that you must make haste and teach it to be very clever, so that it may no longer be said of you, that you are of no use to anybody. And then, my dear child, remember that a day will come, when the revered hands that now take care of your childhood--those hands which to-day are yours, as it were--will become weak and incapacitated by age. You will be strong, then, probably, and the assistance which you receive now, you must then render to her, render it to her as you have received it--that is to say, with your hands. It is the mother's hand which comes and goes without ceasing about her little girl now. It is the daughter's hand which should come and go around the old mother hereafter--her hand and not another's. Here again, my child, the mouth is nothing without the hand. The mouth says, "I love," the hand proves it. LETTER III. THE TONGUE. Now, about this doorkeeper, or porter, as we will call him, of the mouth. I do not suppose you have guessed who he is; so I am going to tell you. The porter who keeps the door of the mouth is _the sense of taste_. It is he who does the honors of the house so agreeably to proper visitors, and gives such an unscrupulous dismissal to unpleasant intruders. In other words, it is by his directions that we welcome so affectionately with tongue and lips whatever is good to eat, and spit out unhesitatingly whatever is unpleasant. I could speak very ill of this porter if I chose; which would not be very pleasant for certain little gourmands that I see here, who think a good deal too much of him. But I would rather begin by praising him. I can make my exceptions afterwards. In the history I am going to give you, my dear child, there is one thing you must never lose sight of, even when I do not allude to it; and that is, that everything we shall examine into, has been expressly arranged by God for the good and accommodation of our being in this world; just as a cradle is arranged by a mother for the comfort of her baby. We must look upon all these things, therefore, as so many presentsfrom the Almighty himself; and abstain from speaking ill of them, were it only out of respect for the hand which has bestowed them. Moreover, there is a very easy plan by which we may satisfy ourselves of the usefulness and propriety of these gifts--namely, by considering what would become of us if we were deprived of any one of them. Suppose, for instance, that you were totally deficient in the sense of taste, and that when you put a piece of cake into your mouth, it should create no more sensation in you than when you held it in your hand? You would not have thought of imagining such a case yourself, I am aware; for it never comes into a child's head to think that things can be otherwise than as God has made them. And in that respect children are sometimes wiser than philosophers. Nevertheless, we will suppose this for once, and consider what would happen in consequence. Well, in the first place, you would eat old mouldy cake with just the same relish as if it were fresh; and this mouldy cake, which now you carefully avoid because it is mouldy, is very unwholesome food, and would poison you were you to eat a great deal of it. I give this merely as an instance, but it is one of a thousand. And although, with regard to eatables, you only know such as have been prepared either in shops or in your mamma's kitchen, still you must be aware there are many we ought to avoid, because they would do no good in our stomachs, and that we should often be puzzled to distinguish these from others, if the sense of taste did not warn us about them. You must admit, therefore, that such warnings are not without their value. In short, it is a marvellous fact that what is unfit for food, is _almost always_ to be recognized as it enters the mouth, by its disagreeable taste; a further proof that God has thought of everything. Medicines, it is true, are unpleasant to the taste, and yet have to be swallowed in certain cases. But we may compare them to chimney-sweepers, who are neither pretty to look at, nor invited into the drawing-room; but who, nevertheless, are from time to time let into the grandest houses by the porters--though possibly with a grimace--because their services are wanted. And in the same way medicines have to be admitted sometimes--despite their unpleasantness--because they, too, have to work in the chimney. Taste does not deceive you about them, however; they are not intended to serve as food. If any one should try to breakfast, dine, and sup upon physic he would soon find this out. Besides, I only said _almost_ always, in speaking of unwholesome food making itself known to us by its nasty taste; for it is an unfortunate truth that men have invented a thousand plans for baffling their natural guardian, and for bringing thieves secretly into the company of honest people. They sometimes put poison, for instance, into sugar--as is too often done in the case of those horrible green and blue sugar plums, against which I have an old grudge, for they poisoned a friend whom I loved dearly in my youth. Such things as these pass imprudently by the porter, who sees nothing of their real character--Mr. Sugar concealing the rogues behind him. Moreover, we are sometimes so foolish as not to leave the porter time to make his examination. We swallow one thing after another greedily, without tasting; and such a crowd of arrivals, coming in with a rush, "forces the sentry," as they say; and whose fault is it, if, after this, we find thieves established in the house? But animals have more sense than we have. Look at your kitten when you give her some tit-bit she is not acquainted with--how cautiously and gently she puts out her nose, so as to give herself time for consideration. Then how delicately she touches the unknown object with the tip of her tongue, once, twice, and perhaps three times. And when the tip of the tongue has thus gone forward several times to make observations (for this is the great post of observation for the cat's porter as well as for ours), she ventures to decide upon swallowing, but not before. If she has the least suspicion, no amount of coaxing makes any difference to her; you may call "puss, puss," for ever; all your tender invitations are useless, and she turns away. Very good; here then is one little animal, at least, who understands for what end she has received the sense of taste, and who makes a reasonable use of it. Very different from some children of my acquaintance, who heedlessly stuff into their mouths whatever comes into their hands, without even taking the trouble to taste it, and who would escape a good many stomach-aches, if nothing else, if they were as sensible as Pussy. This is the really useful side of _the sense of taste_; but its agreeable side, which is sufficiently well known to you, is not to be despised either, even on the grounds of utility. You must know, between ourselves, that eating would be a very tiresome business if we did not taste what we are eating; and I can well imagine what trouble mammas would have in persuading their children to come to dinner or tea, if it were only a question of working their little jaws, and nothing further. What struggles--what tears! And setting aside children, who are by no means always the most disobedient to the will of a good GOD, how few men would care to stop in the midst of their occupations, to go and grind their teeth one against another for half-an-hour, if there were not some pleasure attached to an exercise not naturally amusing in itself? Ay, ay, my dear child, were it not for the reward in pleasure which is given to men when they eat, the human race, who as a whole do not live too well already, would live still worse. And it is necessary that we should be fed, and well fed too, if we would perform properly here below the mission which we have received from above. Yes, "reward" was the word I used. Now it seems absurd to you, perhaps, that it should be necessary to reward a man for eating a good dinner? Well, well, GOD has been more kind to him, then, than you would be. To every duty imposed by Him upon man, He has joined a pleasure as a reward for fulfilling it. How many things should I not have to say to you on this subject, if you were older? For the present, I will content myself with making a comparison. When a mother thinks her child is not reasonable enough to do, of her own accord, something which it is nevertheless important she should do, as learning to read, for instance, or to work with her needle, &c., she comes to the rescue with rewards, and gives her a plaything when she has done well. And thus GOD, who had not confidence enough in man's reason to trust to it alone for supplying the wants of human nature, has placed a plaything in the shape of pleasure after every necessity; and in supplying the want, man finds the reward. You will hardly believe that what I have here explained to you so quietly by a childish comparison, has been, and alas! still is, the subject of terrible disputes among grown-up people. If hereafter they reach your ears, remember what I have told you now, viz., that the pleasure lodged in the tongue and its surroundings, is a plaything, but a plaything given to us by GOD; and that we must use it accordingly. If a little girl has had a plaything given to her by her mother, would she think to please her by breaking it or throwing it into a corner? No, certainly not: she would know that in so doing she would be going directly against her mother's intentions and wishes. Nevertheless she would amuse herself with it in play hours, with an easy conscience, and, if she is amiable, she will remember while she does so, that it comes to her from her mother, and will thank her at the bottom of her heart. It is the same with man, of whose playthings we are speaking. But, moreover, this little girl (it is taken for granted that she is a good little girl) will not make the plaything the business of her whole day, the object of all her thoughts; she will not forget everything for it, she will leave it unhesitatingly when her mamma calls her. Neither will she wish to be alone in her enjoyments, but will gladly see her little friends also enjoy similar playthings, because she thinks that what is good for her must be good for others too. It is thus that man should do with his playthings; but, alas! this is what he does not by any means always do with them, and hence a great deal has been said against them. Little girls, in particular, are apt to fail on this point, and that is how the dreadful word _gluttony_ came to be invented. For the same reason, also, people get punished from time to time; such punishments being the consequence of the misuse I speak of. If people who call to see your mamma were, instead of going straight up stairs to her, to establish themselves at the lodge with the porter, and stay there chatting with him, do you think she would be much flattered by their visits? And yet this is exactly what people do who, when eating, attend only to the porter. He is so pleasant, this porter; he says such pretty things to you, that you go on talking to him just as if he were the master of the house, who, meanwhile, has quite gone out of your head. You heap sugar-plums upon sugar-plums, cakes upon cakes, sweetmeats upon sweetmeats--everything that pleases the porter, but is of no use whatever to the master of the house. And then what happens? The master gets angry sometimes, and no wonder. Mr. Stomach grows weary of these visits, which are of no use to him. He rings all the bells, makes no end of a noise in the house, and forces that traitor of a porter who has engrossed all his company, to do penance. You are ill--your mouth is out of order--you have no appetite for anything. The mamma has taken away the plaything which has been misused, and when she gives it back, there must be great care taken not to do the same thing over again. I have thought it only right, my dear child, in telling you the history of eating, to give to this little detail of its beginning, a place proportioned to your interest in it. You see by what I have said, that you are not altogether wrong in following your taste; but neither must it be forgotten that this part of the business is not in reality the most important; that a plaything is but a plaything, and that the porter is not the master of the house. Now that we have made our good friend's acquaintance, we will wish him farewell, and I will presently introduce you to his companions of the antechamber, who are ranged on the two sides of the door, to make the toilettes for the visitors who present themselves, and to put them in order for being received in the drawing-room. You will see there some jolly little fellows, who are also very useful in their way, and whose history is no less curious. They are called TEETH. LETTER IV. THE TEETH. When you were quite little, my dear child, and still a nursling, you had nothing behind your lips but two little rosy bars, which were of no service for gnawing an apple, as they were not supplied with teeth. You had no need of these then, since nothing but milk passed your lips, neither had your nurse bargained for your having teeth to bite with. You see that God provides for everything, as I have already said, and shall often have occasion to point out to you. But by degrees the little infant grew into a great girl, and it became necessary to think of giving her something more solid than milk to eat; and for this purpose she required teeth. Then some little germs, which had lain dormant, concealed within the jaws, awoke one after another, like faithful workmen when they hear the striking of the clock. Each set to work in his little cell, and with the help of some phosphorus and some lime, it began to make itself a kind of white armour, as hard as a stone, which grew larger from day to day. You know what lime is; that sort of white pulp which you have seen standing in large troughs where the masons are building houses, andwhich they use in making mortar; it is with this that your little masons build your teeth. As to phosphorus, I am afraid you may never have seen any; but you may have heard it spoken of. It is sold at the druggist's in the form of little white sticks, about as thick as your finger; they have a disagreeable, garlicky smell, and are obliged to be kept in jars of water, because they seize every opportunity of taking fire; so I advise you, if ever you do see any phosphorus, not to meddle with it--for in burning, it sticks closely to the skin, and there is the greatest difficulty in the world in extinguishing it, and the burns it makes are fearful. I give you this caution, because phosphorus possesses a very curious property, which might attract little girls. Wherever it is rubbed, in the dark, on a door, or on a wall, it leaves a luminous trail of a very peculiar appearance, which has been called phosphorescent, from the name of the substance which produces it. And in this way one can write on walls in letters of fire, to the terror of cowards. Now, come; if you will promise to be very wise, and only to make the experiment when your mamma is present, I will teach you how to make phosphorescent lights without having to go to the druggist's! There is a small quantity of phosphorus in lucifer matches, which their garlicky smell proves. Rub them gently in the dark on a bit of wood, and you will see a ray of light which will shine for some moments. But mind, you must not play at that game when you are alone; it is a dangerous amusement, and one hears every day of terrible accidents caused by disobedient children playing with lucifer matches. And while we are on the subject, let me warn you against putting them into your mouth. Phosphorus is a poison, and such a powerful one that people poison rats with bread-crumb balls in which it has been introduced. "Oh dear me! and that poison makes part of our teeth?" Exactly so, and it even forms part of all our bones, and of the bones of all animals; the best proof of which is, that the phosphorus of lucifer matches has been procured out of bones from the slaughter-house. One could make it from the teeth of little girls if one could get enough of them. Now I see what puzzles you, and well it may. You are asking yourself how those little tooth-makers, the gums, get hold of this terrible phosphorus, which is set on fire by a mere nothing, and which we dare not put into our mouths; where do they find the lime which I also protest is not fit to eat, and yet of which we have stores from our heads to our feet? It is very surprising, too, to think of its being forthcoming in the jaws just when it is wanted there. You begin to perceive that there are many things to be learnt before we come to the end of our history, and that we find ourselves checked at every step; now listen, for we are coming to something very important. In distant country-seats, where people are thrown entirely upon their own resources, they must be provided beforehand with all that is requisite for repairing the building; and there is, accordingly, a person called a steward, who keeps everything under lock and key, and distributes to the workmen whatever materials they may require. Thus, the steward gives tiles to the slater, planks to the carpenter, colors to the painter, lime and bricks to the mason--the very same lime that we have in our teeth--in fact, he has got everything that can be wanted in his storehouse, and it is to him that every one applies in time of need. Now our body also is a mansion, and has its steward too. But what a steward--how active! what a universal genius I how inefficient by comparison are the stewards of the greatest lords! He goes, he comes, he is everywhere at once; and this really, and not as we use the phrase in speaking of a merely active man: for the _being everywhere at once_ is in this case, a fact. He keeps everything, not in a storehouse, but what is far better, in his very pockets, which he empties by degrees as he goes about, distributing their contents without ever making a mistake, without stopping, without delaying; and returns to replenish his resources in a ceaseless, indefatigable course, which never flags, night nor day. And you can form no idea how many workmen he has under his orders, all laboring without intermission, all requiring different things--not one of them pausing, even for a joke!--not even to say--"Wait a moment;"--they do not understand what waiting means: he must always keep giving, giving, giving. By and by we shall have a long account to give of this wonderful steward, whose name, be it known, if you have not already guessed it, is Blood. It is he who, one fine day when he was making his round of the jaws, found those little germs I spoke of, awake and eager for work; and he began at once to start them with materials. He knew that phosphorus and lime were what they needed: he drew phosphorus and lime therefore out of his pockets,--and, to be very exact, some other little matters too,--but these were the most important; but I cannot stop to tell you everything at once. Now, where did the blood obtain this phosphorus and lime? I expected you to ask this, but if you want everything explained as we go along, we shall not get very far. In fact, if I answer all your questions I shall be letting out my secret too soon, and telling you the end of my story almost before it is begun. So be it, however; perhaps you will feel more courage to go on, when you know where we are going. The steward of a country-house distributes tiles, planks, paint, bricks, lime; but none of these things are his own, as you know; he has received them from his master: and, in the same way, our steward has nothing of his own: everything he distributes comes from the master of the house, and as I have already told you, this master is the stomach. As fast as the steward distributes, therefore, must the master renew the stores--and renew them all, for unless he does this, the work would stop. In proportion as the blood gives out on all sides the contents of his pockets, the stomach must replenish them, and fill them with everything necessary, or there would be a revolution in the house. Now, as there can be nothing in the stomach but what has got into it by the mouth, it behooves us to put into the mouth whatever is needed for the supply of our numerous workmen; and this is why we eat. I perceive that I have plunged here into an explanation out of which I shall not easily extricate myself, for I can guess what you are going to say next. When you began to cut your teeth, you had eaten neither phosphorus nor lime, as nothing but milk had entered your mouth. That is true. Neither then, nor since then, have you eaten those things, and what is more, I hope you never will. And yet both must have got into your mouth, for without them your teeth could never have grown. How are we to get out of this puzzle? Suppose now, for a moment, that instead of phosphorus and lime, thelittle workmen in your jaws had asked the blood for sugar to make the teeth with. Fortunately this is only a supposition; otherwise I should be in great fear for the poor teeth: they would not last very long. Suppose, further, that instead of your eating the lump of sugar which was destined to turn into a tooth, your mamma had melted it in a glass of water, and had given it to you to drink; you could not say you had eaten sugar, and yet the sugar would really have got into your stomach, and there would be nothing very wonderful if the stomach had found it out and given it to the blood, and the blood had carried it off to the place where it was wanted. Now, allowing that the lump of sugar was very small, and the glass of water very large, the sugar might have passed without your perceiving it, and yet the tooth would have grown all the same, and without the help of a miracle. And this is how it was. In the milk which you drank as a baby there were both phosphorus and lime, though in very small quantities. There were many other things besides; everything of course that the blood required for the use of its work-people, because at that time the stomach was only receiving milk, and yet all the work was going on as usual. And therefore, my dear child, whenever in the course of our studies, you hear me describe such and such a thing as being within us, say quietly to yourself, "that also was in the milk which nourished me when I was a baby." Of course, the same things are in what you eat now; only now they come in a form more difficult to deal with, and the labor of detaching them from the surrounding ingredients is much greater. The whole business indeed of this famous machine which we are studying consists in unfastening the links which hold things together, and in laying aside what is useful, to be sent to the blood divested of the refuse. The stomach was too feeble in your infancy to have encountered the work it has to do now. It is for this reason that God devised for the benefit of little children that excellent nourishment--milk--which contains, all ready for use, every ingredient the blood wants; and is almost, in fact, blood ready made. Only think, my child, what you owe to her who gave you this nourishment! It was actually her blood she was giving you; her blood which entered into your veins, and which wrought within you in the wonderful way which I have been describing. Other people gave you sugar-plums, kisses, and toys; but she gave you the teeth which crunched the sugar-plums, the flesh of the rosy cheeks which got the kisses, and of the little hands which handled the toys. If ever you can forget this, you are ungrateful indeed! Now, beware of going on to ask me how we know that there are so many sorts of things in milk, or I shall end by getting angry. Question after question; why, you might drive me in this way to the end of the world, and we should never reach the point we are aiming at. We have already traveled far away from the teeth, concerning which I wanted to talk to you at this time, but our lesson is nearly over and we have scarcely said a word about them! One cannot learn everything at once. Upon the point in question you must take my word; and as you may believe, I would not run the risk of being contradicted before you, by those who have authority on the subject. Let it suffice you, for to-day, to have gained some idea of the manner in which the materials which constitute our bodies are manufactured within us. We have got at this by talking of the teeth; to-morrow, it may be the saliva, the next day something else. What I have now told you will be of use all the way through, and I do not regret the time we have given to the subject. If you have understood that well; the time has not been lost. LETTER V. THE TEETH _(continued.)_ My thoughts return involuntarily to the subject I last explained to you, my dear child, and I find that I have a great deal to say about it still. You see now, I hope, that we have something else to consult besides a dainty taste when we are eating; and that if we are to work to any good purpose we must think a little about this poor blood; who has so much to do, and who often finds himself so much at fault, when we send him nothing but barley-sugar and biscuits for his support. It is not with such stuff as that, as you may well imagine, that he can be enabled to answer satisfactorily to the constant demands of his little workmen, and we expose him to the risk of getting into disgrace with them, if we furnish him with no better provisions. And who is the sufferer? Not I who am giving you this information, most certainly. Now, when children hesitate about eating plain food, and fly from beef to rush at dessert, they act as a man would do who should begin to build by giving his workmen reeds instead of beams, and squares of gingerbread instead of bricks. A pretty house he would have of it;--just think! On the contrary, what your mother asks you to eat, my dear little epicure, is sure to be something which contains the indispensable supplies for which your blood is craving; for people knew all about this by experience long before they could explain the why and the wherefore. But now that you are so much better informed than even the most learned men were a century ago, pouting and wry faces at table are no longer excusable, and I should be sadly ashamed of you if I should hear you continued to make them. And this is what I was more particularly thinking of just now, when I took up my pen again. No doubt it is very amusing to be able to look clearly into one's frame, and see what goes on inside, but the amusement anything affords is the least important part of it; you have begun to find this out already, and you will find it out more and more every day. What seems to me one of the great advantages of the study we have begun together is, that at every step you take you will meet with the most practical and useful instruction, as well as the most unanswerable reasons for doing what your parents ask you to do every day. To obey without knowing why is certainly possible, and may be done happily enough. But we obey more readily and easily when we understand the reason for doing so; and a duty which one can satisfy oneself about, forces itself upon one as a sort of necessity. And what can throw a stronger light on our duties than a thorough acquaintance with ourselves? It is upwards of two thousand two hundred years ago (and that is not yesterday, you must own!) since one of the greatest minds of the world--Socrates--never forget that name--taught his disciples, as a foundation precept, this apparently simple maxim, "Know thyself." He meant this, it is true, in a much higher sense than we are aiming at in these conversations of ours, but his rule is so practical, that although you have only as yet taken a mere peep into one small corner of self-knowledge, you find, if I am not much mistaken, that your heart has beaten once or twice rather faster than it did before. Was I wrong, in saying from the beginning, that we become better as we grow in knowledge? Is it not true that you have felt more tenderly than ever towards her who nourished you with her milk, since I explained to you the value of milk; and that you have kissed your mother's hand all the more lovingly since you heard my history of the hand? To tell you the truth, if you had not done so, I should have been dissatisfied both with you and myself. And wait! While we are talking thus, another thought has come into my head about hands and nurses, which I must tell you of. There is something of the nurse, my child, in those who take the best fruits of their intellect and heart, and transform them, as it were, into milk, in order that your infant soul may receive a nourishment it will be able to digest without too much effort. In this way their very soul enters into you, and it is but fair that you should reward them as they deserve. Young as you are, too, you have a recompense in your power: one more acceptable even than Academic prizes--of which it is indispensable not to be too avaricious--you can give them your love. Besides, it is not only hands but heads that are at work for you, and of these many more than you suppose; and your debt of gratitude is as much due to the one as to the other. Perhaps my first letter may have led you to suppose that I was inclined to laugh at what I called learned men; and they are perhaps a little to blame for not thinking often enough about little girls; but nevertheless these men are of the greatest use to them in an indirect way. You owe them much, therefore, and without them could have known nothing of what I am teaching you. It is very grand for us, is it not, to know that there is phosphorus and lime in our teeth? But it took generations of learned men, and investigations and discoveries without end, and ages of laborious study, to extract from nature this secret which you have learnt in five minutes. And whatever others you may learn hereafter, remember that it is the same story with all. While profiting, therefore, at your ease, by all these conquests of science, I would have you hold in grateful recollection those who have gained them at so much cost to themselves: almost always at the expense of their fortune, sometimes at the peril of their lives. There they are, observe, a little knot of men with no sort of outward pretension. They speak a language which scares children away. They weigh dirty little powders in apothecaries' scales; steep sheets of copper in acid-water; and watch air-bubbles passing through bent glass tubes, some of which are as dangerous as cannon balls. They scrape old bones, and slice scraps no bigger than a pin's head. They keep theireyes fixed for hours upon things they are examining through microscopes of a dozen glasses, and when you go to see what they are looking at, you find nothing at all. To see them at work, in what they call their laboratories, you would say that they were a set of madmen. But at the end, it is found, some fine day, that they have changed the face of the earth; have worked revolutions before which emperors and kings bow in respect; have enriched nations by millions at a time; have revealed to the human race, divine laws of which it had hitherto been ignorant; finally, have furnished the means of teaching little boys and girls some very curious things, which will make them more agreeable as well as reasonable. And this is a benefit not to be despised, since these children are destined one day to become fathers and mothers, and so to govern the next generation; and the better they themselves are instructed, the better this will be done. But now let us go back to the poor teeth, whom we seem to have forgotten altogether. However, we knew very well that they would not run away meantime. I told you before that it was their business to dress and prepare whatever was presented to them, but the reception they bestow is not one which would suit every body's taste, for it consists in being made mince-meat of And in order to do their work in the best way possible they divide their labor; some cut up, others tear, and others pound. First, there are those flat teeth in front of the two jaws, just below the nose. Touch yours with the tip of your finger; you will find that they terminate in sharp-edged blades, like knives. These are called _incisors,_ from the Latin word _incidere,_ which means to cut, and it is with them we bite bread and apples, where the first business is to cut. It is with the same teeth that lazy little girls bite their thread, when they will not take the trouble to find their scissors; and, by the by, this is a very bad trick, because by rubbing them one against another in this manner we wear them out, and, as you will soon discover, worn-out teeth never grow again. The next sort are those little pointed teeth, which come after the _incisors,_ on each side of both jaws. You will easily find them; and if you press against them a little, you will feel their points. If we call the first set the knives of the mouth, we may call these its forks. They serve to pierce whatever requires to be torn, and they are called _canine_ teeth, from the Latin word _canis_, a dog, because dogs make great use of them in tearing their food. They place their paws upon it, and plunging the canine teeth into it, pull off pieces by a jerk of the head. Look into the mouth of papa's dog: you will recognize these teeth by their rather curved points. They are longer than the rest, and are called fangs. I do not know, after all, why they have chosen to name these teeth _canine_, as all carnivorous animals have the same fangs, and in the lion, the tiger, and many other species, they are much more developed and sharper than in the dog. In cats they are like little nails. However, the name is given, and we cannot alter it. The last teeth, which are placed at the back of the jaw, are called molars, from the Latin word _mola_, which means a millstone. You must be prepared to meet with several Latin words as we go on; but never mind; this will give you the opportunity of learning a little Latin, and so of keeping your brother in order, if he ever looks down upon you because he is learning Latin at school. Formerly, all learned men wrote in Latin, and as they ruled supreme in all such subjects as those we are discussing, they gave to everything such names as they pleased, without consulting the public, who did not just then trouble their heads about the matter. Now they give Greek names, which can hardly be called an improvement; but if they ever wish to attract the attention of little girls they must translate their hard words into our own language. To return to our grinders: they perform the same office as a miller's millstone; that is to say, they grind everything that comes in their way. These teeth have flat, square tops, with little inequalities on the surface, which you can feel the moment you lay your finger on them. These are the largest and strongest of the three sets, and with them we even crack nuts, when we prefer the risk of breaking our teeth to the trouble of looking for the nut-crackers! Now, I will answer for it that you cannot explain to me why we always place what is hard to break between the _molars,_ and never employ the _incisors_ in the work? And yet everybody does this alike--from the child to the grown-up man--and all equally without thinking of what they are doing. I will tell you the reason, however, if you will first tell me why, when you are going to snip off the tip of your thread (which offers very little resistance), you do it with the point of your scissors; whereas you put any tough thing which is likely to resist strongly (a match, for instance) close up to their hinge; particularly if you have no scruple about spoiling the scissors, by the way! If you were a grown-up lad, and I were teaching you natural philosophy, I should have here a fine opportunity for explaining what is called _the theory of the lever_. But I think _the theory of the lever_ would frighten you; so we must get out of the difficulty in some other way. I find, however, that I have been joking so much as I went along, that I have but little space left, and feel quite ashamed of myself. We seem quite unlucky over these teeth. I have already been scolded by people who are not altogether wrong in accusing me of losing my time in chattering, first of one thing and then of another. They complain that by thus nibbling at every blade of grass on the way-side we shall never get to the end of our journey; and there is some truth in what they say. Still, I will whisper to you in excuse that I thought we might play truant a little bit while we were on familiar ground, where naturally you were sure to feel a particular interest in everything. The hand, the tongue, the teeth--these are all old friends of yours--and I thought you would like to hear all about them. By-and-bye we shall be in the little black hole, and then we shall get on much more rapidly. LETTER VI. THE TEETH _(continued)._ I left off at the _molars_, which are the teeth one selects to crack nuts with; and if I remember rightly, we talked about different ways of cutting with scissors. Let us look at the subject from a distance, that we may understand it more clearly. Let us imagine a horse drawing a heavy cart slowly along. Ask it to gallop, and it will answer, "With all my heart! but you must give me a lighter carriage to draw." And now fancy another flying over the ground with a gig behind it. Ask it to exchange the gig for the cart, and it will say, "Yes; but then I shall have to go slowly." Whereby you see that with the same amount of strength to work with, one has the choice of two things: either of conquering a great resistance slowly, or a slight one quickly. And it is partly on this account, dear child, that I teach you so gradually; for young heads, fresh to the work, are less easily drawn along than others, and have but a certain amount of strength. Hitherto all has been clear as the day. Now take your scissors in your left hand; hold the lower ring of the handle firmly between your thumb and closed hand, so that the blade shall remain straight and immovable: then with your other hand cause the upper ring to go up and down, and watch the blade as it moves. The whole of it moves at once, and is put in motion by the same power--viz., your right hand. But the point makes a long circuit in the air, while the hinge end makes only a very little one--indeed, moves almost imperceptibly: and, as you may imagine, a different sort of effort is required from the motive power (your hand) according as resistance is made at the point or at the hinge. The point goes full gallop: it is the horse in the gig; the light work is for him. The hinge moves slowly; it is the cart-horse, and takes the heavy labor. I hope I have made you understand this, for it explains the cracking of our nut, though you may not suspect it. Move your scissors once more in the same way. Now, you have before you the pattern of the two jaws on one side of your face, from the ear to the nose; the upper one, which never moves (as you may convince yourself by placing a finger on your upper lip when you either speak or eat), and the lower one which goes up and down. Two pairs of scissors set points to points give you the whole jaw. The _incisors_ are at the points, they gallop up and down, and are worthless for doing hard work; the _molars_ are at the hinges, and move slowly; and if anything tough has to be dealt with, it comes to them as a matter of course; hence they are the nutcrackers. You must own that it is pleasant to reflect thus upon what we are doing every day, and the next time you see a stonemason moving stones of twenty times his own weight with his iron bar, ask your papa to explain to you the principle of the lever. After what I have told you, you will understand it very readily, or at least enough of it to satisfy your mind. But, besides this power of moving up and down, the lower jaw possesses another less obvious one, by means of which it goes from right to left. This is precisely what naughty children make use of when they grind their teeth: not that I mean this remark for you, for I have a better opinion of you than to suppose you do such things. Those who make such bad use of their jaws deserve to lose the power of ever moving them thus, and then they would find themselves sadly at a loss how to chew their bread--for their _molars_ would be of but little service to them in such a case; as it is chiefly by this second action of the jaw that the food is pounded. Try to chew a bit of bread by only moving your jaw up and down, and you will soon tire of the attempt. One word more to complete my description of the teeth: that portion of them which is in the jaw is called the _root_; and the _incisors_, which cannot work hard because, like the gig-horses, they have but little resisting power, possess only small and short roots; whereas the _canines,_ whose duty it is to tear the food sideways, would run the risk of being dragged out and left sticking in the substances they are at work upon, if they were not well secured; these, therefore, have roots which go much deeper into the jaw, and in consequence of this they give us more pain than the others when the dentist extracts them: those famous _eye-teeth_, which so terrify people on such occasions, are the _canines_ of the upper jaw, and lie, in fact, just below the eye. The _molars_ meanwhile would be in danger of being shaken in the sideway movement, while chewing: so they do as you would do if you were pushed aside. Now you would throw out your feet right and left in order to steady yourself, and thus the molars, which have always two roots, throw them out right and left for the same purpose. Some have three, some four, and they require no less for the business they have to do. Above the root comes what is called the crown; that is the part of the tooth which is exposed to the air; the part which does the work, and which bears the brunt of all the rubbing. Now, however hard it may be, it would soon end in being worn out by all this fun if it were not covered by a still harder substance, which is called _enamel_. The _enamel_ which forms the coating of china plates, and which you can easily distinguish by examining a broken plate, will give you a very exact idea of it. It is this enamel which gives the teeth the polish and brilliancy we so much admire, and it is desirable to be very careful of it, not out of vanity, though there is no objection to a little vanity on the subject, but because the enamel is the protector of the teeth, and when that is destroyed, you may say good-bye to the teeth themselves. All acids eat into the enamel, as vinegar or lemon-juice does into marble; and one of the best means of preserving this protecting armor of the teeth is never to eat the unripe windfalls of fruit, which I have seen unreasonable children pick up in orchards and devour so recklessly. They give sufficient warning, by their acidity, that they are not fit for food, and when this warning is neglected, they take their revenge by corroding the enamel of the teeth; not to speak of the disturbance which they afterwards cause in the poor stomach. I said that without this coating of enamel, the teeth would be prematurely worn out, the reason of which is, that the teeth have not the property of growing again, as the nails and hair have. When those little germs of which I spoke when we began to describe the teeth, have finished their work, they perish and fall out, like masons who, when they have built the house, take their departure forever. But the "forever" wants explanation. For such stern conditions would fall hard on very little children, who, not having come to their reason, cannot be expected to understand the great value of their teeth, and take all the care they need of them. So to them _a second_ chance is given. Your first teeth, the _milk-teeth_, as they are called, count for nothing: they are a kind of specimen, just to serve while you are very young. When you are approaching what is called the age of reason, (and this word implies a great deal, my dear child,) the real teeth, the teeth which are to serve you for life, begin to whisper among themselves, "Now, here is a little girl who is becoming reasonable, and who will soon, or else never, be fit to take charge of her teeth." No sooner said than done: other masons set to work in other cells, placed under the first set, and as the permanent teeth keep growing and growing, they gradually push out the milk-teeth, which were only keeping their places ready for them till they came. This is just your case at present, and you now understand your responsibility, and how necessary it is to preserve those good teeth which have placed so generous a confidence in your care of them, and which, once gone, can never be replaced. You have no loss by the exchange; you had twenty-four at first, you will now have twenty-eight. Twenty-eight, did I say? nay, you will have thirty-two; but the last four will come later still. The last _molars_ on each side, above and below, in both jaws, will not make their appearance till you are grown up. They are a fastidious and timid set, and will not run any risks; and they are called _wisdom-teeth_, because they do not appear till we are supposed to have arrived at years of discretion. Some people do not cut them before they are thirty, and you will agree that, if they have not become wise by that time, they have but a very poor chance of ever being so! There is much more still to be said about the teeth; but I think I have told you quite enough to teach you the importance of these little bony possessions of yours, which children do not always value as they deserve, and whose safety they endanger as carelessly as if they had fresh supplies of them ready in their pockets. If so many skilful contrivances have been devised for enabling us to masticate our food properly, it is clear that this process is not an unimportant one. Those, therefore, who swallow a mouthful after two or three turns, forget that they are thereby forcing the stomach to do the work the teeth have neglected to do, and this is very bad economy, I can assure you. You will see hereafter, when we speak about animals, that by a marvellous compensation of nature, the power of the stomach is always great in proportion to the _in_efficiency of the teeth, and that by the same rule, it is weakest when the jaws are best furnished. Now, no jaw is more completely furnished than the human one; it is clear, then, that it should do its own work and not leave it to be done by those who are less able: and the little girl who, in order to finish her dinner more quickly, shirks the use of her teeth, and sends food, half chewed, into her stomach, is like a man who, having two servants, the one strong and vigorous, the other feeble and delicate, allows the first to dawdle at his ease, and puts all the hard work on the other. He would be very unjust in so doing, would he not? And as injustice always meets with its reward, his work is sure to be badly done. Now, the work in question consists in reducing what we eat into a sort of pulp or liquid paste, from which the blood extracts at last whatever it requires. But the teeth may bite and tear the materials as they please, they can make nothing of them but a powder, which would never turn into a pulp, if during their labors they were not assisted by an indispensable auxiliary. To make pap for infants what do we add to the bread after it is cut in little bits? Without being a very clever cook, you will know that it is water which is wanted. And thus, to assist us in making pap for the blood, Providence has furnished us with a number of small spongy organs within the mouth, which are always filled with water. These are called _salivary glands_. This water oozes out from them of itself, on the least movement of the jaw, which presses upon the sponges as it goes up and down. The name of this water, as I need scarcely tell you, is _saliva_. When I call it water, it is not merely from its resemblance; _saliva_ is really pure water with a little _albumen_ added. Do not be afraid of that word--it is not so alarming as it appears to be. It means simply the substance you know as the _white of egg_. There is also a little soda in the water, which you know is one of the ingredients of which soap is made. And this explains why the saliva becomes frothy, when the cheeks and tongue set it in motion in the mouth while we are talking; just as the whites of egg, or soapy water, become frothy when whipped up or beaten in a basin. But the albumen and the soda have not been added to the saliva, in our case, merely to make it frothy; that would have been of very little use. They give to the water a greater power to dissolve the food into paste, and thus to begin that series of transformations by which it gradually becomes the fine red blood which shows itself in little drops at the tip of your finger when you have been using your needle awkwardly. When once minced up by the teeth and moistened by the saliva, the food is reduced to a state of pulp, and having nothing further to do in the mouth, is ready to pass forward. But getting out of the mouth on its journey downwards is not so simple an affair as getting into it by the _front door_, as it did at first. Swallowing is in fact a complicated action, and not to be explained in half a dozen words, and I think we have already chatted enough for to-day. I only wish I may not have tired you out with these interminable teeth! But you may expect something quite new when I begin again. LETTER VII. THE THROAT. You remember a certain door-keeper, or porter, of whom we have already spoken a good deal, who resides in the mouth--the sense of taste, I mean? Well, it is a porter's business to sweep out the entrance to a house, and you may always recognize him in the courtyard by his broom. And accordingly our porter too has a broom specially placed at his service, namely, the tongue; and an unrivalled broom it is--for it is self-acting, never wears out, and makes no dust--qualities we cannot succeed in obtaining in any brooms of our own manufacture. When the time has come for the pounded mouthful (described in the last chapter) to travel forward (the teeth having properly prepared it), the broom begins its work; scouring all along the gums, twisting and turning right and left, backwards and forwards, up and down; picking up the least grains of the pulp which have been manufactured in the mouth; and as the heap increases, it makes itself into a shovel--another accomplishment one would scarcely have expected it to possess. What it gathers together thus, rolls by degrees on its surface into a ball, which at last finds itself fixed between the palate and the tongue in such a manner that it cannot escape; at which moment the tongue presses its tip against the upper front teeth, forms of itself an inclined plane, and--but stop! we are getting on too fast. At the back of the mouth, (which is the antechamber, as we said before,) is a sort of lobby, separated from the mouth by a little fleshy tongue_let_, suspended to the palate, exactly like those tapestry curtains which are sometimes hung between two rooms, under which one is enabled to pass, by just lifting them up. If this lobby led only from the mouth to the stomach, the act of swallowing would be the simplest thing in the world; the tongue would be raised, the pounded ball would glide on, would pass under the curtain, and then good-bye to it. Unfortunately, however, the architect of the house seems to have economized his construction-apparatus here. The lobby serves two purposes; it is the passage from the mouth to the stomach, as well as from the nose to the lungs. The air we breathe has its two separate doors there--one opening towards the nose, the other towards the lungs; through neither of which is any sort of food allowed to pass. But, as you may imagine, the food itself knows nothing of such spiteful restraints, and it is a matter of perfect indifference to it through which of the doors it passes. Not unlike a good many children who, though they are reasonable creatures, will push their way into places where they have been forbidden to go; and who can expect a pulpy food-ball to be more reasonable than a child? It was necessary, therefore, so to arrange matters that there should be no choice on the subject; that when the food-ball got into the lobby it should find no door open but its own, namely, that which led to the stomach. And that is exactly what is done. You have not, perhaps, remarked that in the act of swallowing, something rises and contracts itself at the same moment in your throat, producing a kind of internal convulsion which jerks whatever is inside. People do not think about it when they are eating, because it is an involuntary action, and their attention is otherwise engaged. But try to swallow when there is nothing in your mouth, and you will perceive what I mean at once. Now, imagine our lobby at the back of the throat as a small closet, with a doorway in its wall, half-way up, the doorway being closed by a curtain. In the ceiling is a hole, which leads to the nose; in the floor two large tubes open out; the front one leading to the lungs, the one behind, to the stomach. Now swallow, and I will tell you what happens. The curtain rises up and clings to the ceiling, and thus the passage to the nose is stopped up. The lung-tube rises along the wall, and hides itself under the door, contracting itself, and making itself quite small, as if it wished to leave plenty of room for the mouthful of food which is about to pass over it; and, for still greater security, at the very moment it rises, it pushes against a small trap-door which shuts up its mouth. No other road remains, therefore, but through the tube which leads to the stomach; the pulpy mouthful drops straight therein, without risk of mistake, and when it is once there, everything readjusts itself as before. These are very ingenious contrivances, and I will venture to say that if we would but study the wonders of the marvellous and varied machinery which is constantly at work in our behalf within us, we should be much better employed than in learning things from which no practical good can be derived. Moreover, we should be ashamed to trust, like the lower animals, only to our instinct, (which, after all, is much less developed in us than in them,) for blindly escaping the thousand chances of destruction that beset a structure so fragile and delicate in its contrivances as the human body. Besides, it is not only our own machinery that is entrusted to us, we are liable to be responsible for that of others, whose development it is our duty to guard and watch; and how can we do this with a safe conscience, if we are ignorant of the construction, the action, the laws of all sorts which the great Artificer has, so to speak, made use of in forming our bodies? When you, in your turn, are a mother, you dear little rogue, who sit there opening wide your bright eyes, and not comprehending a word of what I am saying, you will be glad that you were taught when you were little, how your own little girl ought to be managed. You will find a hundred opportunities of making good use, in her behalf, of what you and I are learning together, and in the meantime there is no reason why you should not yourself profit by the knowledge you have gained. I am quite sure, for instance, that in repeating to your child the simple rule of politeness, with which everybody is acquainted, "_Never talk when you are eating_," you will be very careful to add, "_and especially when you are swallowing_," for reasons I am about to detail. When we want to speak we have to drive the air from the lungs into the mouth, and our words are sounds produced by this air as it passes through. This is the reason why I advise you to go on gently, and make the proper stops in reading aloud: to _take breath_, in fact, as it is called; otherwise, breath would all at once fail you, and you would be obliged to stop short in the middle of a sentence and wait like a simpleton till you had refilled the lungs with air by breathing. It was for this purpose, also, and not for mere economy's sake, as you may have thought, that the little cross-road of four doors has been placed at the back of the mouth, enabling it to communicate at pleasure with either the lungs or the stomach. It is a dangerous passage for food-parcels making their way to the stomach; but if you could substitute for it, as it may have occurred to you to do lately, a simple tube going directly to the stomach,--behold! you would find yourself dumb;--a serious misfortune, eh? for a little girl! But come, I am quizzing too much, so console yourself. I know many grown-up people who would be at least as sorry as yourself. To return to our subject. We have said that, in order to guard against accidents, the lung-tube is closed at the moment we are about to swallow. But if by any unlucky chance the air is coming up from the lungs at the same moment, it must have a free passage. Its tube cannot help returning to its place; the little trap-door which shuts up the opening opens whether or no, and then adieu to all the precautions of good Mother Nature! The mouthful when it drops, falls outside of its proper tube--that is to say, into the other, which is exactly in front of it, and we find that we have _swallowed the wrong way_. You know what happens in such a case. You cough and cough till you are torn to pieces, till you grow scarlet, or even blue in the face; till you lose your breath; till your body trembles; till your eyes start out of their sockets. Let who will be there, there is no resource but to hide your face in your handkerchief. The tube, which was only made for the passage of air, on finding an intruder forcing an entrance, does its utmost to drive it back through the door. Then the lungs, which would be destroyed by its getting to them, come to the assistance of the faithful servant who is struggling for their protection: they agitate themselves violently, and send forth gusts of air which drive all before them. Thence arises the cough, and by this means at last the enemy is thrust out of the mouth, like dust before the wind. And it is only when the passages are cleared that the storm subsides. But the commotion is no laughing matter, I assure you; for if one had swallowed a little _too far_ the wrong way, or if the substance swallowed had been too heavy for the air-tube, aided by the lungs, to eject within a certain time, death would have ensued: instances of which are by no means unknown. Nature does nothing in vain; this is no case of a man frightened by a mouse. When you find your whole being concentrating its efforts to one point, and betraying such distress, at an accident apparently so trifling, you may be sure there is danger, and real danger too; and if you doubt it, that makes no difference--happily for you. Now you have learned why little girls should not attempt to talk and swallow at the same time, and, I may add, still less laugh; for laughingis a kind of somersault, performed by the lungs, and is always accompanied by the ejectment of a great deal more breath than is necessary in speaking, so that the jerks it occasions derange still more the wise provisions made to protect life whenever we swallow anything, and therefore we are more apt to swallow the wrong way while laughing than while speaking. Need I say that we ought equally to guard against making others laugh or talk; or exciting, or frightening them, while they are swallowing; in short, avoid doing anything to create a sudden shock which might suddenly force the air out of their lungs, and cause them in the same manner to swallow the wrong way? Politeness requires this from us, and what I have now said will fix the lesson still more strongly on your mind. What would become of you if you were to see a person die in your presence in consequence of some foolish joke, however apparently innocent? Not to conclude with so painful a picture, I will, before we part, give you the right names of the _curtain_, the _lobby_ or _closet_, and the _tubes_ of which we have been speaking. The curtain is called the _Soft Palate_. The lobby, the _Pharynx_. The tube which leads to the stomach, the _Aesophagus_. The tube leading to the lungs, the _Larynx_. The opening of this tube is the _Glottis_, and the little trap-door which closes it when one swallows, is the _Epiglottis_. You must excuse my attempting to explain the meanings of all these names; it would take me too long to do so. After all, the mere names are nothing. If I have succeeded in making you understand how all the different parts act, you may call them what you like. Here we will rest. We are now on our way to where we shall see the large apartments, and be introduced to the master, that head of the house, whom no one can approach without so many ceremonies. LETTER VIII. THE STOMACH. Once in the _oesophagus_ (you remember this is the name of the tube which leads to the stomach), the mouthful of food has nothing to do but to proceed on its way. All along this tube there is a succession of small elastic rings, [Footnote: Properly, _contractile circular fibres_.] which contract behind the food to force it forward, and widen before it to give it free passage. They thus propel it forward, one after another, till it reaches the entrance to the stomach, into which the last ring pushes it, closing upon it at the same time. Have you ever observed a worm or a leech in motion? You see a successive swelling up of the whole surface of its body, as the creature gradually pushes forward, just as if there was something in its inside rolling along from the tail to the head. Such is precisely the appearance which the _oesophagus_ would present to you, as the food passes down it, if you had the opportunity of seeing it in action; and this has been called _the vermicular movement_, in consequence of its resemblance to the movement of a worm. Here I wish to draw your attention to the very important fact, that this movement is in one respect of a quite different nature from that of your thumb when you take hold of a bit of bread, or that of your jaw when you bite with your teeth, or of your tongue, &c., when you swallow. All these actions belong to yourself, to a certain extent; they are voluntary, and under your own guidance; that is, you may perform them or not, as you choose. There is a constant connexion between you and them, and you knew what I meant at once as I named each of them in succession. But in speaking of this other movement we enter upon another world, of which you know nothing. Here is the black hole of which I spoke. The little rings of the _oesophagus_ perform their work by themselves, and you have no power in the matter. Not only do they move independently of you, but were you to take it into your head to stop them, it would be about as wise a proceeding as if you were to talk to them. We will speak hereafter, in another place, of these impertinent servants, who do not recognise your authority, and with whom we shall have constantly to do, throughout what remains to be said on the subject of eating. The truth is, your body is like a little kingdom, of which you have to be the queen, but queen of the frontiers only. The arms, the legs, the lips, the eyelids, all the exterior parts, are your very humble servants; at your slightest bidding they move or keep still: your will is their law. But in the interior you are quite unknown. There, there is a little republic to itself, ruling itself independently of your orders, which it would laugh at, if you attempted to issue them. This republic, to make use of another metaphor, is the kitchen of the body. It is there they make blood, as they know how; putting it to all sorts of uses for your advantage, it is true, but without your consent. You are in the position of the lady of a house whose servants have shut the door of the kitchen in her face that they may carry on their business after their own fashion, leaving only the housemaid and coachman at her command. It may be humiliating, perhaps, to be thus only partially mistress at home; but what can you do, my little demi-queen? I will tell you: make up your mind to govern the subjects under your orders as wisely as possible; and, as to the rest, be content with the only resource left you: viz., that of looking in at the window of the kitchen to see what goes on there! The stomach is the head cook: the president of the internal republic. He has charge of the stoves; the whole weight of affairs is on his hands, and he provides for the interests of all. Aesop taught us this, long ago, in his fable of "The Belly and Members." [Footnote: La Fontaine's translation is quoted in the French original, where the name of the fable is "_Messer Gaster_," a more correct title than our own. _Gaster_ is a Greek word signifying stomach; and it is strictly _the stomach_ which is _meant_ in the fable. From this comes, too, the medical term _gastritis_, the name of a disease of the stomach.--TR.] It is a very good fable, and was wisely appealed to once by a Roman Consul to appease a disturbance in the State. But the application was not quite fair in one respect; and since I have started the subject, I will satisfy myself by explaining to you where it was wrong. The time will not be wasted, for this fable has furnished information to a great many people about the economy of their insides, and possibly to you; and I should like you to know the exact truth of all the particulars alluded to. Whether Aesop understood them all, I cannot pretend to say; but the application by the old Roman to the quarrel between the big-wig senators and the people was on one point decidedly unjust; for there was, as far as facts are concerned, something to be said on behalf of the stomach, which Consul Menenius seems not to have thought of. When you come to this part of the Roman history you will learn that the Roman Senate was a large and fat stomach, which did, it is true, furnish good nourishment to the other members of the State, but kept the best share for itself. We may say this now without risk of offence, it having been dead for so long a time. Our stomach is the leanest, slightest, frailest part of our body. It is master in the sense in which it is said in the Gospel, "Let him that is first among you be the servant of the others." It receives everything, but it gives everything back, and keeps nothing, or almost nothing, for itself. Between ourselves, Consul Menenius, the advocate of the Senate, had no business to talk to the poor wretches at Rome of any comparison between their government and so careful an administrator of the public good as a human stomach. He should have taken his subject of comparison from the families of geese or ducks--animals which have no teeth. These have strong, well-grown stomachs--true Roman senators--whose stoutness is in proportion to the work given them to do. But man provides his with work already prepared by chewing, supposing him to have had the sense to chew it, of course. It was not from a comparison with man, therefore, that Menenius ought to have got his boasted apologue, which was but a poor jest on the subject. You did not expect, my dear, to come in for a lesson on Roman History in a discussion on the stomach. But the study of nature is connected with everything else, though without appearing to be so, and I was not sorry to give you, incidentally, this proof of the unexpected light which it throws, as we go along, upon a thousand questions which appear perfectly foreign to it. Look, for example, at this old fable cited by Menenius. For the two thousand years and upwards that it has been in circulation, troops of historians, poets, orators, and writers of all kinds, have passed it forward from one to the other, without having troubled themselves to investigate the laws of nature in connection with the stomach; therefore, not one, that I am aware of, has observed this small error, so trifling in appearance, so important in reality, which nevertheless is obvious to the first young naturalist who thinks the matter over. But enough of the Romans. Let us return to our master--the head cook, if you choose to call him so. I was telling you just now that he managed the stoves, and you may have thought that I was merely using similes, as I am apt to do. But not so: it is quite true that he cooks; and so now tell me, if you can, whence he gets his fire to cook with, or rather, to speak more correctly, who gives it to him? Now you are quite puzzled, so I must help you out. In the mansion we were talking about some time ago, to whom would anyone who wanted to light a fire, apply for wood? I think you can answer this yourself, for you cannot have forgotten our famous steward, who gives everything to everybody. But, you will wonder, I dare say, how the blood can carry wood in his pockets. Wood? Ay, and real wood too, as we shall soon see: but it is not wood we are talking about now. The blood has something more to the purpose than wood in his pockets, for he has heat ready made. So when the stomach wishes to set to work, it appeals to the blood, which comes running from all parts of the body, and heats it so effectually that everything within is really and actually cooked. This is why one feels a sort of slight shudder down the back when the stomach has a great deal to do at once, for the blood being called for in a hurry, comes rushing along in great gushes, and carries with it the heat from the other parts of the body. It is for this reason, too, that it is so dangerous to bathe when the stomach is at work cooking, because the cold of the water drives suddenly back all the blood which has accumulated around the little saucepan, and this causes such a shock in the body that people often die of it. Do not ask me, to-day, where this heat of the blood comes from; we will speak of that hereafter. But I may tell you at once that our dear steward is not a bit cleverer in this matter than other people, and obtains his heat, like the humblest mortal, by burning his wood. Do not puzzle yourself to find out how. Enough that he burns it as we do, and by a similar process. Well, in one way or another, the master cook has his fire at command. You know also, already, what it is he has to get cooked; namely, the pulpy stew, which has begun in the mouth by chewing, and which it is his business now to finish perfectly. Now see what a cook does who has got her stew over the fire. She turns and turns it again and again, and shakes the saucepan from time to time, that the ingredients may be more thoroughly mixed up together; and this is precisely what is done by the stomach; for all the time that the cooking is going on, he swells and contracts himself alternately, after the fashion of those rings of the _oesophagus_ we were talking about, tossing and tumbling the food from one side to another, so as to knead it, as it were. Again, the cook adds water to her stew from time to time to keep it moist; and so the stomach pours constantly upon his stew a liquid, which contains a great deal of water, and which flows in from a quantity of little holes, sunk in his delicate coats. What more? The cook puts in a little salt: and this the stomach takes care not to forget either, for he is a cook who understands his business. In the liquid of which I am speaking, there is, if not exactly salt as one sees it at table, at all events the most active part of salt, that which possesses in the highest degree the property of reducing everything we eat to a paste; and this is the real reason why we find all food so insipid which has not been seasoned with salt. As salt contains a principle essential to the work to be done by the stomach, some method had to be devised to induce us to provide him with it, and this method the porter up above has hit upon. He makes a face if we offer him anything without a little salt on it, as much as to say--"How can you expect them to cook you properly down below, my good friend, if you don't bring them proper materials?" Upon which hint men have always acted from the beginning; and as far as we can trace history back, we find them mixing salt with their food, though without knowing the real reason why. It is the same, too, with the lower animals. They know nothing of the matter either, but this does not prevent their having a natural relish for salt, as any one will tell you who has the charge of cattle; for their stomachs require for their cooking the very same seasoning as our own, and therefore their porter above has received the same orders. Salt is not the only thing, however, that exists in that liquid in the stomach. Learned men, after making minute researches, have found in it another equally powerful material, which is also found in milk. Therefore cheese, which contains this material as well as salt, is quite in its place at the end of dinner. It furnishes reinforcements for the stomach in cooking, and this is why you so often hear people say that a little cheese helps the digestion. The _digestion_! Yes, that is the word I ought to have begun with. It is the real name of all this cooking; an operation after which I would defy you to recognise the nice little cakes you have eaten, any better than your mamma can trace her pretty rosy-cheeked apples in the jelly which she left on the fire two hours ago. The stomach, as you see, is very busy quite as long a time as that, and if we have to be very careful (as I pointed out before) not to disturb him too suddenly in his work after dinner, it is also important that we should not, while at dinner, give him more work to do than he is capable of doing. Although he is the master, he is but a puny fellow, as I have already pointed out; nevertheless, he works conscientiously, because he knows that the life of the whole body depends upon his exertions. Some people even say that in spite of his leanness he strips himself, at each digestion, of his interior skin, which he sacrifices to his work, and the fragments of which tend to increase and improve the stew which is entrusted to his care. Think of this, my dear, whenever a greedy fit comes over you, and recollect that such a disinterested public functionary deserves some consideration. Besides, there is serious danger, quite apart from any question of injustice, in overwhelming him with work. If your legs are wearied out, you have it in your power to lie in bed. If your arm is in pain, you can keep it at rest. But your stomach is like those poor people who have to support their families by the labor of each day. He, too, labors for others: he has no right to rest, no right to be ill, therefore; and when he begins to fail, woe betide you--you will have enough of it. Children who have learnt nothing may laugh at all this, but you, my dear, are beginning to know something, and "science constrains," _i.e._ it has its claims and requirements. It requires you, to-day, not to be greedy, to-morrow, something else, and so on, continually, until you have become quite reasonable and wise. I am sorry for you if this vexes you, but it was your own wish to learn, and _science constrains_. Indeed, I will whisper to you in confidence that this is the best excuse people who are unwilling to learn have to offer for refusing. They do not know what learning may lead to, and what a pity it would be if they could no longer be greedy, or ill-natured, or selfish. What would become of us all in such a case? LETTER IX. THE STOMACH--_(continued)_. We made a very long story of the stomach last time, my dear child; and, after all, I see that there was one thing I forgot to tell you--viz., what it is like. Have you ever seen a bagpiper, I wonder? A man who carries under his arm a kind of large dark brown bag, which he fills with air by blowing into it, and out of which he presently forces the same air into a musical pipe by pressing it gently with his elbow. If you never saw such a thing, it is a pity; first, because the bagpipe was the national instrument of our ancestors the Gauls, and is religiously preserved as such by the Scotch Highlanders and the peasants of Brittany--(two remnants of that illustrious race, whose history I recommend to your careful perusal some day); secondly, and it is this fact which has the greatest interest for us just now, because that large bag, which is the principal part of the instrument, gives you a very exact idea of your stomach; for in fact it really and truly _is_ a stomach itself, and moreover, the stomach of an animal whose interior formation resembles yours very, very much. And who do you suppose is this audacious animal, which presumes to have an inside so like that of a pretty little girl? Really, I am half ashamed to name him, for fear you should be angry with me for doing so. It is--it is the pig! The resemblance is not exactly a flattering one to you, perhaps, but we are all alike, and it would be worse than foolish to grumble at being created as we are. Moreover, there is one difference; the pig, who thinks of nothing but eating, has a very much larger stomach than we have, which is some consolation, at any rate. Place the palm of your right hand on what is called the pit of the stomach, turning the ends of the fingers towards the heart; your hand will nearly cover the space usually occupied by the stomach, and you may figure it to yourself as a rounded and elongated bag, bigger above than below, making a very decided bend inside as it descends from the heart downward; something like one of those long French pears, called "Bon-chretiens," if it were bent in the middle, and the big end of it were placed next the heart. As for the exact size of the bag, there is no telling it, for it depends upon circumstances. It is a very convenient bag in that respect; just such a one as you would like to have in your frock for a pocket; only there would be a danger of your being tempted to put too many things into it. For as you fill it, it expands, and enlarges itself like an indian-rubber ball, which, though only the size of an egg to begin with, becomes as big as your head if you blow hard into it. Then, as it gets empty, it recovers itself, diminishing gradually in size in plait-like contractions. When people remain too long without eating, they have, as they say, twinges in the stomach. This is because the stomach, becoming by degrees quite empty, and contracting more and more, the surrounding parts which were sustained by it, lose their support, and strain at their ligaments, which now have all the weight to bear. Careless people, who do not think of such things, are reminded by the twinging pains that it is time to eat, just as a careless servant is called to order by the bell of which his master has pulled the string. In your case, my dear child, such warnings are soon attended to, and you have not always even to wait till they come. But there are hundreds of miserable beings who are warned to no purpose, who cannot obey the master when he calls for his rations, because they have nothing to give him; and when this forced disobedience lasts too long, they end by dying of it. In cases like these, when human beings thus cruelly perish, the stomach is found to be contracted till it is scarcely bigger than one's finger. On the other hand, a man once died suffocated from excess of food, after one of those great public dinners, which last four, six, or more hours--one can scarcely say correctly how long--and the doctors who examined him found his stomach so prodigiously enlarged that it alone occupied more than one-half of his inside. As you perceive, therefore, the stomach has, properly speaking, no fixed size. Its size depends upon what there is in it. It is like those men whose manners go up and down with their fortunes; who seem very grand people when their pockets are well filled, but become very small ones when their purses are empty. There is, nevertheless, this difference between them, that such men are fools, because they are men, and not _bags_; whereas the stomach is a sensible bag, fulfilling with intelligence the duties of its character as a bag. It is very fortunate for us that it is ready to change its size, according to the caprices of our appetite; and dressmakers would do well if they could get a hint from it how to improve their style of pockets, which certainly cannot have cost their inventors any very great effort of imagination! The way in which this extraordinary pocket empties itself is not less curious than the rest. As long as digestion is going on, the stomach is firmly closed at each end; at the upper one by the last ring of the _aesophagus_, and at the lower by another ring of the same kind, only stronger; the watchful guardian of the passage which leads to the intestines. This ring is called the _pylorus_. For once, here is a name which agrees with our method of describing the human machine, and I have much pleasure in translating it to you, although it is a Greek word. _Pylorus_ is the Greek for a porter; and our ring is indeed a porter like the one of which we have already said so much, and which I called last time the _porter up above_, in anticipation of his colleague below. The porter up above presides at the entrance; the one below at the exit, and both for the same purpose, namely, to _taste._ [Footnote: It would be absurd to say so in the common acceptation of the term; but according to No. 1 of Mr. Mayo's "Classification of the impressions produced by substances taken into the fauces," viz., _"Where sensations of_ touch _alone are produced, as by rock-crystal, sapphire, or ice,"_ the word taste may be applied to the discriminating faculty of the _Pylorus_.--TR.] It may well astonish you, that you should have in your inside a taster who is not accountable to you; who experiences sensations of which you know nothing, and cannot even form an idea. Yet thus it is. The _pylorus_ actually tastes the paste which is in the stomach, and if it is not to his taste, that is to say, if the work of digestion has not sufficiently transformed it for use, he keeps the door relentlessly closed. The porter up above has a thousand different tastes. He makes his bow to meringues, and admits wings of chickens. Fries, roasts, stews, things tender or crisp, sweet and salt, oily, greasy, or sour; amongall kinds he has friends whom he welcomes in succession; and it is well for us that he does so, for we share in all his pleasures. The porter below, who works for himself alone, obscure and unknown down in his black hole, the porter below, I say, has but one taste, knows but one friend--a gray-looking paste, semi-liquid, with a very peculiar unsavoury smell, disagreeable enough to any one but himself, which is called the _chyme_, I scarcely know why, but it is what everything one eats turns into, without exception, be it delicate or coarse by nature. The great lord's truffle-stuffed pullet makes, as nearly as possible, the same _chyme_ as the charcoal-burner's black bread; and though the palate of the former may be better treated than that of the latter, the _pylori_ can enjoy but one and the selfsame sauce. Equality is soon restored in this case, therefore, as you see. To be free to pass through then, the contents of the stomach must be reduced to the condition of _chyme,_ the only substance which finds favor with the _pylorus:_ and as, in the endless varieties of food which go to form our nutriment, some sorts turn into _chyme_ much more quickly than others, it follows, that by the aid of its discriminating tact (which is not easy to elude) the _pylorus_ allows some to pass, while it turns back others, until all in succession are converted into chyme. For example, in the case of a mouthful of bread and meat swallowed at once, the bread passes away on its travels long before the meat has done dancing attendance in the stomach, awaiting that transformation without which the _pylorus_ will never allow it to slip through. This ought to make you seriously reflect on the danger of carelessly swallowing things, which, by their nature, are not susceptible of being converted into _chyme,_ particularly if they are too large to hide in the general paste, as a cherry-stone will sometimes do, so mixed up with other food as to pass unperceived by the _pylorus,_ over whose decisions we have no control, remember. It bangs the door to, be assured, in the very face of anything obnoxious without hesitation, and the poor stomach would find itself condemned to retain them for an indefinite period, unless by dint of prayers and supplications they should contrive to soften the stern guardian, who may at last get accustomed to their approach, and, perhaps, in a weak moment, allow them to pass as contraband goods; like a custom-house officer on a foreign frontier who will occasionally shut his eyes to a country friend's packet of tobacco. But the poor stomach has had to suffer a martyrdom meantime, while the dispute was pending, and before the intruder has been winked at by the porter. I shall remember all my life the history of a peach-stone, which was related to me in 1831. I was at the time a youngster at the Stanislaus College, and (aided perhaps by the Revolution of July, which had recently occurred), it was just then discovered to be a proper thing to set about teaching the laws of nature to children. Consequently, for the first time in the history of schools, a professor of natural history was added to the instructors of Latin and Greek. I leave you to judge how we opened our ears to his lessons. When we arrived in the course of our new studies at the _pylorus,_ of which we had none of us ever heard before, our professor, in warning us, as I have done you, of the dangers of imprudent gluttony, related, as an instance, the case of a lady who had inadvertently swallowed a peach-stone. For two years she suffered agonies in her stomach without any cessation or relief. The luckless peach-stone, repelled by the walls of the stomach, which its very touch irritated, was incessantly thrown against the entrance of the _pylorus,_ but in vain. As to turning itself into _chyme,_ such a thing was not to be thought of, it was far too hard a substance for that. Round and round it went, causing in its relentless course such renewed suffering to the poor patient, that she was visibly sinking from day to day. The doctors, finding all their treatment of no avail, began to despair of her life, when one fine day she was suddenly, and as if by enchantment, relieved of her tormentor. The peach-stone had bribed the porter, with whom, in the course of the two years, it had scraped up a sort of friendship. It had cleared the terrible barrier, had been allowed to slip out, and the lady was saved; but it was only just in time. I do not know, my dear, that this story, which is certainly well calculated to cure you of any fancy for swallowing peach-stones, willmake as much impression on you as it did on me five-and-twenty years ago. The idea of telling it to you occurred to me quite by chance. It has carried me back to the time when, as is now the case with you, the mysteries which lie hidden in our internal organization were beginning to be revealed to my mind; and you will one day know with what delight one recalls the remembrance of these first dawnings of the intellectual life--that delightful infancy of the growing mind--more rich in recollections, and more interesting a thousand fold than the infancy of the body. I have allowed myself the little treat of this episode, and if I have had the good fortune to amuse you at all during our progress, you must not cavil at this piece of self-indulgence. And now we have done just what the peach-stone did; we, too, have passed the barrier, and are out of the stomach, but still we have not yet come to the end of our tale. LETTER X. THE INTESTINAL CANAL. I venture to hope, my dear child, that more and more light is dawning upon your mind, as we gradually proceed on our little journey. You must by this time have some idea how the food, which has been masticated and softened in the mouth, cooked, kneaded, and decomposed in the stomach, and transformed into a soft, semi-transparent kind of paste, will soon be ready to mix with the blood, in order to repair the waste that the life-stream is continually undergoing in its ceaseless course through all parts of the body. You have perhaps thought it a sad degradation for a truffle-stuffed fowl to turn to _chyme._ But when you consider that by this means it becomes part and parcel of a human body, the change is not to be despised. It was necessary, to begin with, that materials destined to the honor of being incorporated into our frame, should break the links which bound them to the condition of fowl and vegetable, and thus be free to engage in new relations; just as a man who wishes to be naturalized in a new country must first break the ties which hold him to the old one. Those articles of food we were speaking of lately, which are so stiff and ceremonious, and want so much coaxing before they change into _chyme,_ which, moreover, we call _indigestible_ because they tire the stomach so much more than the rest, are merely those whose component parts being held together by more solid ties than usual, continue obstinately in the same state as at first, and will not consent to that dissolution which is the first condition of their glorious transformation. Moreover, the transformation which has been described to you now, you will henceforth meet with everywhere; wherever, that is to say, and as far as, you choose to pursue the study of nature. God works by one grand and simple rule so far as we can discover. He destroys to reconstruct, builds up what is to be, out of the ruins of what has been, creates life by death, if I may so express myself, and thus, what takes place in our stomachs on a small scale goes on on a large one in the universe. Social communities, like everything else, are subject to this universal law, and it is not always an advantage to them when they refuse to be digested in the great stomach of the age! While we are on this subject, and to show you how wonderfully this little history of eating, told in this familiar style, applies right and left, let us reflect on the causes which have produced a great and mighty nation in one country (as in France), while in another (as in. Germany), a far more numerous and even more intellectual population has failed to rise to anything like the same distinction. The explanation is not difficult. In the one case, the petty tribes among which the land was originally divided consented to mix, and dissolve, and be digested as it were together, in order to revive again for a more glorious career; while in the other, the aboriginal societies have adhered stiffly to their distinctive characters, and failing to submit to the regenerating process, cling together in indigested portions, rather than assimilate into one great whole. However, we must return to the _pylorus_ or we shall be getting into a difficulty! What I am now going to offer you though, is rather hard of digestion, but it will not do to provide sweet pastry only for your brain; it will be more wholesome for it to have something a little more solid to bite at from time to time. The _pylorus_, then, as has been shown, makes way for all sorts of aliments when they have been converted into _chyme; i.e._, when they have lost their original form and individuality. They are dead to their first life, therefore; now the question is, how are they to be revived into the new one? Behind the _pylorus_ extends a long conduit or tube--so long as to be sometimes seven times the length of the whole body, but doubled up backwards and forwards a number of times, so as to form a large bundle, which fills the whole cavity of the belly--or as we also call it, the _abdomen_. This bundle or packet is known to everybody as _the intestines_, and it is divided into two portions: the _small intestine_--that is, the slenderer, finer portion which begins at the _pylorus_, and forms all the doublings of the packet, and the _large intestine_, which is shorter and thicker also, as its name implies, and keeps to some extent separate, though it is in reality only a continuation of the other. This starts at the base of the _abdomen_, near the right side, goes up in a straight line to the height of the stomach, below which it passes, making a large bend in front of the small intestine; after which it descends on the left side to the lower part of the trunk, where it terminates. You will perhaps inquire how the _chyme_ continues to make its way through all these manifold twists of the intestines; but do not trouble yourself; it has only to let itself go. That _vermicular movement_ which we noticed in the _oesophagus_ and in the _stomach_ is found here also. It reigns, so to speak, from one end of our internal eating-machine to the other; which eating-machine, by the way, we will now call by its proper scientific name--_the intestinal canal_; and it is by that movement the food is carried forward from the first moment it leaves the mouth, and helped through all its journeyings, till it reaches the termination of the large intestine. If your body were made of glass, so that you could look through it to watch the intestine at work, it would appear to you like an enormous worm coiled up into a bundle, heaving and moving with all its rings at once. You never suspected there was such a movement within you; yet it has been going on there continually ever since you were born, and will not cease till you die. Your internal machinery never goes to sleep, not even when you are sleeping yourself. It is a workshop in constant operation, providing night and day for your necessities; and in this respect the inner man sets a first-rate example to the outer one! You will recollect what I said to you the other day about the internal republic, and the provinces which are under your sole government. It would be very disgraceful for the kingdom to be doing nothing while the republic is working so hard; and a queen who understands her office will make it a point of honor to banish idleness from her household; in the houses of her neighbors this word is unknown. The _chyme_ once launched into this moving tube, is in no danger of remaining stationary there; the fear is, of its passing on too quickly, as you will soon see. But this danger has been provided against. Along the whole course of its journey, though chiefly at the commencement, it encounters at intervals certain elastic fleshy valves which interrupt its progress, and do not allow it to pass till it has accumulated in sufficient force to push them before it, and so escape. In consequence of which it is always being checked in its advance; and during these stoppages a most important work goes on upon it at leisure. You must understand first, that the substances of which our food is composed, and which are afterwards decomposed in the stomach, are not all invited to enter the blood. Our aliments are something like the stones which the gold-seekers of California reduce to powder in order to extract therefrom the hidden particles of gold they contain. The gold of our food is that portion of it which the blood is able to appropriate to his own advantage; the rest he rejects as refuse. And this explains why a small slice of meat nourishes you more than a whole plateful of salad. Meat is a stone absolutely full of gold, while the salad has only a few veins of it here and there, and by far the greater part of the material it sends to the intestines, has, in consequence, to be thrown away. Now it is in the first portion of the small intestine, the part known by the Latin name _duodenum,_ which signifies twelve (because it is about the length of twelve finger-breadths), that the division takes place between the parts which go to nourish the blood, and those which are useless refuse. It is an important operation as you may suppose, and were the _chyme_ to pass rapidly through the small intestine the gold would run the risk of being carried off with the refuse. After the delay in the stomach, the food-substances make another halt in the _duodenum,_ which, being very thin and slender, would have great difficulty in containing them at the time of their grand entry, an hour or two after a meal, were it not that it possesses the property of expanding itself to such an extent, that it swells out on grand occasions to the usual size of the stomach itself, so that it has sometimes been considered as a second stomach. And no doubt the operation which takes place in it gives it a claim to the appellation, for thereby the finishing stroke is put to the work previously begun in the stomach, and one may fairly say that, but for this last touch, very little would be accomplished at all. Above the _duodenum_, and hid behind the stomach, is a kind of sponge, similar in nature to those we have already observed in the mouth. To this has been given the somewhat ridiculous name of _pancreas_; I call it ridiculous because it is derived from two Greek words which signify _all flesh_; whereas the _pancreas_, which is a sponge of the same description as the salivary glands, presents the appearance of a grayish granulous mass which is not fleshy at all. Whatever be its name, however, our sponge communicates with the _duodenum_ through a small tube, by means of which it pours into the _chyme_, as it accumulates, a copious supply of a fluid exactly like the _saliva_ of the mouth. Just by the place where the tube from the _pancreas_ empties itself into the _duodenum_, another tube arrives bringing also a fluid, but of a different sort. This last comes from the liver, where there is a manufactory of _bile_--an unpleasant yellowish-green liquid, the name of which you have no doubt heard before, and which plays a very important part in the transformation of the aliments. These new agents, the bile and the liver, are far too important to be passed over in a few words; I reserve them, therefore, for my next letter. Meantime, not to leave you longer in suspense, I may say that the separation between the gold and the refuse in the _chyme_ takes place as soon as the latter has received the two liquids furnished by the liver and the _pancreas_. If you ask in what manner the division is accomplished, I confess, to my shame, that I am not able to explain it! What takes place there is a chemical process, and hereafter I shall have occasion to explain the meaning of that phrase. But the Great Chemist has not in this instance seen fit to divulge to man the secret of the work. Indeed, you must prepare yourself beforehand, my dear child, to meet with many other mysteries besides this, if we pursue to the end our study of this flesh and bone which constitute the body of man. And here I recall what Camille Desmoulins is reported to have said about St. Just, viz., that he carried his head as high as if it were a consecrated Host. [Footnote: The young Protestant reader who has never lived in a Catholic country, will perhaps need to be told, that what is here called Consecrated Host, is the sacramental wafer, or communion bread of the church. In French called _hostie_, in Italian, _ostia_. In all their religious processions, which are very frequent, the host is carried by the priest highest in authority, in a glass box placed on a staff about four feet long, which he holds before him and so far elevated that he has to look up to it. Over his head a richly embroidered canopy of satin is always carried by several men; and while these are passing, all good Catholics uncover the head and bend the knee, wherever they may be. It is the custom also for the priest to be called to administer the sacrament to any one about to die, on which occasion he always walks under this canopy, dressed in his priestly robes, carrying the host and preceded by some boys, ringing a bell, when the same ceremony is observed. In passing a regiment or company of soldiers, the column is halted, wheeled into line, and with arms presented, the whole line, officers and men, kneel before it, and the priest usually turns and offers a benediction. When he goes in the evening to the house of the dying, it is customary for the people to go out upon the balconies with lighted lamps and kneel while the host is being carried by.] You will read about these two men by-and-by in history. Meantime I will not bid you do exactly the same as St. Just, because you would be laughed at; but in one point of view he was not altogether wrong. The human body is, in very truth, a temple in which the Deity maybe said to reside, not inactively, not veiling his presence, but living and moving unceasingly, watching on our behalf over the mysterious accomplishment of the everlasting laws which equally guide the _chyme_ in its workings through our frames, and direct the sun in its course through the heavens. We mortals eat, but it is God who brings nourishment out of our food. LETTER XI. THE LIVER. I fear you will be getting a little weary, my dear, of dwelling so long on this intestinal tube, where things which looked so well on one's plate become so transformed that they cannot be recognized, and where there is nothing to talk about but _chyme_, and _bile_, and the _pancreas,_ and all sorts of things neither pleasant to the eye nor agreeable to the ear. But what is to be done? It is always the same story with useful things. The people by whose labor you live in this world, are by no means the handsomest to look at, and so it is in the little world we carry about in our bodies. Never mind! Keep up your heart. We are getting to the end. We shall very soon be following the nourishing portion of our food, on its journey to the blood, and you will find yourself in new scenes. First, though, let us say a few words about the liver--the bile-manufacturer; and to begin with, I will describe the place he occupies in our interior. The interior of the human body is divided into two large compartments, placed one above the other; the _chest_ and the _abdomen_. These are two distinct apartments, each containing its own particular class of tenants: the upper one being occupied by the heart and the lungs (the respective offices of which I will presently explain to you); while in the lower are the stomach, the intestines, and all the other machinery which assists in the process of digestion. These two stories of apartments are separated as those of our houses are, by a floor placed just above the pit of the stomach. This floor is a large thin, flat muscle, stretched like canvas, right across the body; and it is called the _diaphragm_--another hard word! Never mind; but do your best to recollect it, for we shall have great need of it when we come to the lungs. If you had been born in Greece, you would have no difficulty with the word, for it is Greek for _separation_. It means, in fact, a _separating partition_, or, as I called it just now, _a floor._ All this is preparatory to telling you that the liver is hooked to the diaphragm in the abdomen. It is a very large mass and fills up, by itself alone, all the right side of the lower compartment, from the top downwards, to where the bones end which protect the abdomen on each side, and which are called _the short ribs._ Place your hand there, and you will find them without difficulty. Large as the liver is, it hangs suspended to a mere point of the diaphragm, and shakes about with even the slightest movement of the body. It is partly on this account that many people do not like to sleep lying on the left side, especially after a good dinner, because in this position the liver weighs upon and oppresses the stomach, like a stout gentleman asleep in a coach who falls upon and crushes his companion at every jolt of the vehicle. The liver within you produces, then, the same effect that a cat, lying on the pit of your stomach would do, and the result is that you have the nightmare. The liver is of a deep-red color. It is an accumulation of excessively minute atoms, which, when united, form a somewhat compact mass, and within each of which there is a little cell, invisible to the naked eye, where an operation of the highest importance to our existence is mysteriously carried on. It appears a very simple one, it is true, yet hitherto it has baffled all attempts at explanation. Listen, however; the subject is well worthy your careful attention, whether it can be explained or not, and we must look back to take it up from thebeginning. I told you about the thousand workmen constantly busied in every part of our bodies, who call on the blood without ceasing for "more, more." You will remember further that it is to enable the blood to supply these constant demands, that we require food. This being understood, it is not difficult to see why we grow; the difficulty is, rather, to explain why we do not continue to grow. Consider, for instance, the quantity of food you have eaten during the last year. Picture to yourself all the bread, meat, vegetables, fruits, cakes, &c., piled upon a table. Put a whole year's milk into a large earthenware pan, all the sweetmeats into a large jar, all the soup into a great tureen, and see what a huge heap you will have collected together. Then try to recollect how much you have increased in size with all this nourishment, which has entered your body. But reckoning in this way--even supposing the little workmen had used only a half or even a third of the materials in question, and rejected the rest as refuse--you would have to stoop in order to get in at the door; and as for your papa, whose heap must have been bigger than yours, his case would be desperate indeed; and yet he has not grown at all! This is very curious, and I dare say you have never thought about it before. Do you know the story of a certain lady called Penelope, who was the wife of Ulysses, a very celebrated king of whom the world has talked for the last 3000 years--thanks to a poet called Homer, who did him the honor of making him his hero! The husband of Penelope had left her for a long time to go to the wars, and as he did not return, people tried to persuade her to marry again. For peace and quiet's sake, she promised to do so when she should have finished a piece of cloth she was weaving, at which she worked all day long. They thought to get hold of her very soon, but her importunate lovers were disappointed; for the faithful wife, determined to await the return of her husband, unwove every night the portion she had woven during the day; and I leave you to judge what progress the web made in the course of a year! Now, every part of our bodies is a kind of Penelope's web, with this difference--that here the web unravels at one end as fast as the work progresses at the other. As the little masons put new bricks to the house on one side, the old ones crumble away on another--in this manner the work might go on forever without the house becoming bigger; while, on the other hand, the house is always being rebuilt. People who are fond of building, as some are, would quite enjoy having such a mansion as this on hand! At your early age, my love, fewer bricks drop out than are added, and this is why you grow from year to year. At your papa's age, just the same number perish and are replaced; and therefore he continues the same size, although in the course of the year he swallows three times his own weight of food. But when I say this, do not suppose it is an offensive remark, or that I think him either too little a man, or too great an eater; seeing that there are 365 days in the year, and that a quart of water weighs two pounds: I need not say more! But the next question is, what becomes of all the refuse which this perpetual destruction produces? What becomes of it? Have you forgotten our steward who looks after everything? He is a more active fellow than I have represented him! To the office of purveyor-general he adds that of universal scavenger. But in the latter department he obtains help. Wherever he passes along, troops of little scavengers press forward, like himself always busy; and while he holds out a new brick to the mason as he hurries by, the little scavenger slips out the old one and conveys it away. The history of these scavengers is a very curious one, and we shall have to speak about it a little further on. They are minute pipes, _i.e. ducts_, spread all over the body, which they envelope as if with fine net work. They all communicate together, and end by emptying the whole of their contents into one large canal, which, in its turn, empties itself into the great stream of the blood. Imagine all the drains of a great town flowing into one large one, which should empty itself into the river on which the town was built, and you will have a fair idea of the whole transaction. What the river would in such a case be to the town, the blood is to the body--the universal scavenger, as I said before. But you will ask further, What does the blood do with all this?--a question which brings us back once more to the liver. You must have seen, just now, that the pockets of our dear steward would be rapidly overloaded, were he to keep constantly filling them with the old worn-out materials which the builders rejected, unless he had some means of emptying them as he went along. Accordingly, a wise Providence has furnished the body, on all sides, with clusters of small chambers or cells, in which the blood deposits, as he goes by, all the refuse he has picked up, and which makes its exit from the body sometimes in one way, sometimes in another. Now, the cells of the liver are among these refuse-chambers. One may even consider them as some of the most important ones. When the blood has run its course through the lower compartment, I mean the _abdomen_, it collects from all directions and rushes into a large canal called the _portal vein_, which conveys it to the liver. As soon as this canal has entered the liver, it divides and subdivides itself in every direction, like the limbs and branches of a tree diverging from the trunk; and very soon the blood finds itself disseminating through an infinity of small canals or pipes, whose ultimate extremities, a thousand times finer than the finest hairs of your head, communicate with the tiny cells of the liver. There, each of the imperceptible little drops, thus carried into these imperceptibly minute cell-chambers, rids itself--but no one knows how--of a part of the sweepings it has carried along with it. Which done, the little drops thread their way back through other canals as fine as the first, and which go on uniting more and more to each other, like the branches of a tree on their way to the trunk--forming at last one large canal, through which the blood escapes from the liver, once more relieved from its weight of rubbish, and ready to recommence its work. You are going to ask me, "What is all this to me--this history of the blood and its sweepings? It was the bile you undertook to tell me about, that liquid you spoke of as so necessary for the transformation of the food: we were to get out of the intestinal tubes by the help of the bile, you promised me." Well, my little impatient minx, it is the history of the bile that I have been relating to you, and what is most remarkable about it is this. You have perhaps heard of those wholesale ragpickers, who makelarge fortunes by collecting out of the mud and dirt of the streets, the many valuable things which have been dropped there? Well, the liver is the master-ragpicker of the body. He fabricates, out of the refuse of the blood, that bile which is so valuable in the economy of the human frame. This bile is neither more nor less than the deposit left by the little drops of blood in the innumerable minute liver-cells. See what an ingenious arrangement, and in what a simple way two objects are effected by one operation! Now you have learnt the genealogy of the bile, and the double office of the liver, which benefits the blood by what it takes from it, benefits the _chyme_ by what it gives it, and is an economist at the same time--since it only gives back what it has received. This was what I particularly wished to explain to you: the rest you will easily learn. The bile does not make a long stay in the little cells, it also escapes, by canals similar to those which carry off the blood, after itspurification; and which in a similar way unite by degrees together, until at length they terminate in a single canal, communicating with a little bag placed close against the liver, where the bile accumulates between the periods of digestion--so forming a stock on hand, ready to pour at once into the _duodenum_ when the latter calls for its assistance. The next time the cook cleans out a fowl, ask her to show you the little greenish bladder which she calls the gall and which she takes such care not to burst, because it contains a bitter liquid which, if spilt upon it, would quite ruin the flavor of the fowl. Such, precisely, is the bag which holds the bile. Moreover, it is close by the liver of the fowl that you will find it placed: and you can convince yourself in a moment by it, that the little provision I tell you of is always stored away therein. We have also within us a multitude of minute electric telegraphs, which transmit intelligence of all that occurs from one part of the body to another, in a more wonderful manner even than the telegraphs of man's making; later we shall see how they work. By their means the little bag by the liver is made aware in the twinkling of an eye of the entrance of the _chyme_ into the _duodenum,_ and forthwith the bile returns for some distance by the canal which brought it, and then branches off into a larger one which opens into the _duodenum._ The liver, on getting this intelligence, sets to work more diligently than ever, and the bile flows in streams into the _duodenum,_ where it mixes as it arrives with the current which comes from the _pancreas._ Thus combined, the two liquids flow over the _chyme,_ which they saturate on all sides; and here, as I have said, the work of the intestinal canal ends. What is serviceable for the blood is separated from the useless refuse, and nothing remains but to get it out of the intestines. It is true that in their character of tubes these are closed on all sides. But do not trouble yourself: a means of escape is prepared. Before we part, however, I must apologize for something. I have not described to you what the bile consists of, or what kind of refuse the blood leaves in the liver; nevertheless, as you take an interest in this much-neglected book of nature, you ought to know these things. It is, however, very difficult to lead you by the hand through so many wonder*, where the secrets of nature are all in operation at once, and to explain each as soon as we meet with it. They combine, and progress together like the waves of the sea, where one breath suffices to agitate the whole mass. When we have talked about the lungs, we will have another word to say about the liver. LETTER XII. THE CHYLE. To-day we have to begin by making acquaintance with a new term. I would willingly have spared you this, if I could, for the word is neither a pretty, nor a well-chosen one, but we cannot get on without it. You are aware now that the learned, unknown sponsors, who gave names to the different parts of the body, bestowed the odd-enough one of _chyme_ on that pasty substance which passes out of the stomach when the cooking is over. We have said quite enough about it, and you know enough of it I am sure. Well! the people seem to have had quite a fancy for the word _chyme_, for they adopted it again, with only a very slight alteration, when they wanted to specify separately the quintessence of the _chyme_ (the useful part that is), which has to unite with the blood, and which we have been speaking of as the _gold_ of the aliments--this then they called _chyle_. I give you the name as I received it, but have no responsibility in the matter. In concluding the last chapter I said we were sure to find there was a plan for extracting the best part of the _chyme_, viz. the _chyle_, from the intestinal canal; and a very simple one it is. A complete regiment of those little scavengers lately described, are drawn up in battle-array along the whole length of the small intestine, but especially round about the _duodenum._ There, a thousand minute pipes pierce in all directions through the coat of the intestine, and suck, like so many constantly open mouths, the drops of _chyle_ as fast as they are formed. They are called _chyliferous vessels_ or chyle-bearers, just as we might call hot-air stoves _caloriferous_ or heat-bearers--from the Latin word _fero,_ which means to carry or bear. I mentioned before that there were, within the intestine, certain elastic valves which obstruct the progress of the _chyme,_ and oblige it to be constantly stopping. There are in fact so many of these, and the skin which lines the intestinal canal is so folded and plaited, that if it were stretched out at full length on a big table, it would cover at least as large a surface as that other skin, with which you are so well acquainted, which entirely clothes the body outside. Now, the _chyliferous vessels_ we have been speaking of insinuate themselves into all the plaits and folds alluded to, and thus they reach at last the very centre of the _chymous_ paste, and not a single drop of _chyle_ can escape them. They do their work so well, that the separation is effected long before the paste reaches the large intestine; and when that has forced its way through the door which guards the entrance, and which prevents its ever returning again, the _chyle_ is already far off on its mission. It has threaded its way along the little pipes, and, always creeping nearer and nearer, is on the high-road to the heart, where it is anxiously expected. And what becomes of the rest? There is nothing further to be said about it, but that it shares the fate of everything else which, having answered its purpose in its place, is no longer wanted and must be got rid of. Thus in works where iron-stone smelting is carried on, the refuse that remains after the ore is extracted, though available for road-making or other purposes, is thrown out of the manufactory as a useless incumbrance there. Our history requires us to follow the fate of that golden aliment the _chyle,_ which is now in a condition to support the life of the body, and every drop of which will turn into blood--the blood which beats at our hearts, nourishes our limbs, and sets at work the fibres of our brain. I ought to tell you first that the _chyle,_ when it leaves the intestine, is very like milk. It is a white, rather fatty juice, having the appearance, when you look closely at it, of a kind of _whey,_ in which a crowd of globules, or little balls if you prefer it, infinitesimally small, are swimming about. Some people, whose curiosity nothing can check, have put the tips of their tongue to it; so I am able to tell you, if you care for the information, that it has rather a saltish taste. At this point it is what may be called new-born blood, and to carry on the metaphor, blood whose education has yet to be completed. All the elements of blood are there already, but in confusion and intermingled, so that they cannot yet be recognised. A wonderful fact, and one of which I have no explanation to offer you, because among the many mysteries which are silently going on within us is this, that the education of the new-born blood begins entirely of itself in the vessels which are carrying it along. During their very journey, the confused elements are setting themselves in order and forming into groups. In short the _chyle,_ when it comes out of the chyliferous vessels, is already much more like blood than when it entered them, and yet one cannot account for the change. It is changed, however; its whiteness has already assumed a rosy tinge, and if it is exposed to the air it may be seen turning slightly red, as if to give notice to the observer of what it is about to become. You know that all our scavengers uniting together deposit their sweepings in one large canal, which is called the _thoracic duct._ The _chyle_ scavengers arrive there just like the rest, and there our poor friend finds himself confounded for a moment with all the dross of the body, as sometimes happens to men who devote themselves to the public good. But the crisis passes in an instant. A little further off, the _thoracic duct_ pours its whole contents together into a large vein situated close to the heart, and the blood has no difficulty in recognising and appropriating what belongs to him. Here, my dear little scholar, we conclude the first part of our story. To eat is to nourish oneself; that is, to furnish all parts of the body with the substances necessary to them for the proper performance of their functions. The mouth receives these substances in their crude condition, the intestinal canal prepares them for use, and the blood distributes them. After the history of the _preparation,_ comes naturally that of the _distribution._ The first is called the DIGESTION. It is the history of the _chyle,_ which begins between the thumb and forefinger while as yet invisible, hid in the thousand prisons of our different sorts of food, and ends in the _thoracic duct_, when, disengaged from all previous bonds, purified and refined by the ordeals of its intestinal life, it leaps into the blood, carrying with it a renewal of life and power. The second history is that of the CIRCULATION. It is the history of the _Blood,_ that indefatigable traveler, who is constantly _circulating_ or describing a circle (the Latins called it _circulus_) through the body; by which I mean that it is continually retracing its steps, coming out of the heart to return to it, re-entering it only to leave it again, and so on without intermission, until the hour of death. The history of the _Digestion_, which we have just gone through, goes on quietly from one end to the other without any complication. That of the _Circulation_, which we are about to begin, is mixed up with another history, from which it cannot be kept separate while the description is going on, although the two histories are in reality quite distinct from each other. The blood describes two circles, to speak correctly: 1st. A wide one, which extends from the extremities of the body to the heart, and back again from the heart to the extremities. 2d. A more contracted one, which goes from the heart to the lungs, and back from the lungs to the heart. Whilst circulating in the lungs, it encounters the air we breathe; and here takes place, between it and the air, one of the most curious transactions imaginable, without which the blood would not be able to nourish the body even for five minutes. This is called RESPIRATION, or the act of breathing. Digestion, circulation, respiration, the three histories together form but one--that of NUTRITION, or the act of nourishing; in other words, of supporting life. This is what I called _eating_ at first, that I might not mystify you at the beginning with hard words. But now that we are growing learned ourselves, we must accustom ourselves to the terms in use among learned people, especially when they are not more formidable than those I have just taught you. Our next subject for consideration, then, Will be the circulation; and we will begin with the heart, since that is to the circulation what the stomach is to the digestion--viz., master of the establishment. He is a very important person, this heart, as I hardly need tell you. Even ignorant people speak respectfully of him, and I am sure beforehand that his history will interest you very much. Do you feel as I do, my dear child? I am quite happy at having brought you thus far on our journey, and at being able to take a rest with you at the gateway of the new country into which we are about to enter, like travelers sitting down upon a boundary frontier. What a distance we have come, since the day when I took you by the hand to conduct you inside this little body, of which you were making use without knowing anything about it! How many things we have learned already, and how many more remain to be learned, of which you have at present no idea! I assure you I should be almost afraid myself of what is before us yet, if I did not rely upon my own strong desire to instruct you, and the tender affection I bear to you. Believe me, the greatest of constraining powers is love; and when I get bewildered in the midst of some difficult explanation which will not come out clearly, I have only to place before me those laughing eyes of yours, where sleeps a soul that must soon awaken to consciousness, in order to make the daylight come into my own! Must I add, too, that I am not working for you only? We are all placed in this world to help each other, and in striving to bring down light into your intellect, and good sentiments into your heart, I am thinking also of those to whom you, in your turn, may render the same good service hereafter, provided I have the happiness of succeeding now with you. This ought to be so, ought it not? You should resolve to be numbered one day among those who have not lived altogether for themselves, but who have given the world something worth having as they passed through it. To-day's labor will have been well employed if, later on, it turns out that this history of the _chyle_ has not been told you in vain! LETTER XIII. THE HEART. There was once upon a time a banker, a millionaire, who could reckon his wealth not by millions only, but by hundreds of millions and more; who was, in fact, so tremendously rich that he did not know what to do with his money--a difficulty in which nobody had ever been before. This man took it into his head to build a palace infinitely superior to anything that had hitherto been seen. Marbles, carpets, gildings, silk hangings, pictures, and statues--in fact, the whole mass of common-place luxuries as one sees them even in the grandest royal abodes, fell short of his magnificent pretensions. He was an intelligent man, and thoroughly understood the respect due to his riches; and the common fate of kings seemed to him far too shabby for the entertainment of his dynasty, which he looked upon as very superior to all the families of crowned heads in the world. In consequence he sent to the four quarters of the globe for the most illustrious professors, the most skilful engineers, the cleverest and most ingenious workmen in every department; and giving them unlimited permission as to expenditure? ordered them to adorn his palace with all the wonders of science and human industry. Science, and human industry, and unlimited means--what will they not accomplish? No wonder that nothing was talked of for a hundred miles around but the magic building--of which, by the way, I do not venture to give you a description, because it would carry me too far away. Let it suffice to say, that never Emperor of China, Caliph of Bagdad, or Great Mogul had such a habitation as our banker, and for a very good reason--he was twenty times as rich as any such gentry as I have named ever were in their lives. When all was finished one trifling flaw was discovered: the place was not supplied with water. A spring-seeker, who was summoned to the premises, could only discover a small subterranean watercourse, a sort of zigzag pipe, formed by nature, between two beds of clay, in which the rain of the neighborhood collected as in a sort of reservoir. The water was neither very clear nor very plentiful, as you may imagine; and the professor appointed to examine it, having begun by tasting it, made a horrible face, and declared there was no use in proceeding any further; for it had a stagnant flavor which would not be agreeable to my lord. To the amazement of every body, my lord jumped for joy when he heard this unpleasant news. It was proposed to him to fetch water from a river which flowed a few miles' distance off; but he would hear of nothing of the sort. What he wanted was something new, unexpected, impossible--that was his object throughout. He took a pen and drew up at a sitting the following programme, which caused our poor professors to open their eyes in dismay:-- 1st. We will use the water on the premises. 2ndly. It shall flow night day and in all parts of the palace at once. 3rdly. There shall be plenty of it, and it shall be good. The professors looked at each other for some time without speaking, and the gravest of them, whose fortunes and characters had been long ago established, suggested that they should simply give my lord and his money the slip, and so teach him to make fools of people another time! But the youngsters, less easily discouraged, cried out against this with one accord. They declared that the honor of science was at stake, and that they ought to return impudence for impudence, by executing to the letter the impertinent programme! At length, after much discussion and many propositions made against all hope, and thrown aside one after the other as impracticable, a sudden inspiration crossed the brain of an engineer who had not yet spoken; and the following is what he proposed:-- What prevented the water from being sweet and fit to drink, was the want of movement and air. What had to be done, therefore, was to erect a pump, but a pump provided with numberless small pipes, extending to the watercourse in all directions, and so arranged that by means of them it should be able to draw up the water from all the corners and windings where it lay stagnating, and then forcing it forward into a pipe terminating in a rose, like that of a watering-pot, whence it should gush out to fall down in fine rain, into a reservoir in the open air. From thence another action of the pump was to bring it back well aerated, to send it once more into a large pipe with numerous lesser ramifications, which should convey it into every corner of the palace. Up to this point all seemed practicable, but the hardest part had not yet come. The great difficulty was how to supply this enormous consumption with so slender a runnel of water as the one at their disposal. But our engineer had provided for this by a stroke of genius. Under each of the taps (always kept open), which were dispersed all over the palace, he would place a small cistern, from the bottom of which should go a pipe communicating with the body of the force-pump which drew up the water from the original watercourse. By which means the water which ran from the taps would be taken up again and go back to feed the reservoir in the open air; whence it would again return to supply the taps; and so on and on, the same water continually keeping the game alive, as people call it. Have you not sometimes seen at a circus or theatre a large army represented by a hundred supernumeraries, who file in close columns before the audience, going out at one side of the stage and coming in at the other, following close at each other's heels indefinitely? By a similar artifice the engineer would change his meagre little runnel into an inexhaustible fountain. The water drawn up from the watercourse by each stroke of the pump would fully compensate for what was used in its passage through the palace by the inhabitants. Lastly, as it might sometimes happen that the said inhabitants washed their hands under the taps, the water on its return to the cisterns, was to pass through a series of small filters, in order to cleanse it from any impurity it might have contracted by the way. Always flowing, always limpid, it would soon lose every trace of its original source, and might defy comparison with the water of any river in the world! A unanimous buzz of congratulations welcomed this plan, at once so simple and so bold, and our professors thought their troubles were over, but they were not at the end of their difficulties yet. When it came to the actual erection of the machine, (naturally a most complicated one, as it had to set a-going a quintuple system of pipes--pipes from the water-course to the pump, pipes from the pump to the reservoir, pipes from the reservoir to the pump, from the pump to the taps, and from the taps to the pump again,)--our banker, who had got amused and excited as they went on, conducted them to a small dark closet, only a few square feet in size, concealed in a corner of the large apartments, and informed them with a laugh that he had no other place to offer them. Besides which, he made them understand that on account of its situation, there could be no question of furnaces or boilers being set up there (he detested equally coal-smoke, fires, and explosions)--nor of workmen employed about the machine (it would not be decent to have them going up and down the front staircase)--nor above all, of the frightful brake-wheels always screeching and grinding, the unwieldy pistons rising and falling with a noise sufficient to give one the headache. He himself slept near the little dark closet, and the slightest noise was fatal to his repose. Having explained all this, the rich man curtly made his bow and retired. For once our professors owned themselves beaten. They had come forward quite proud of their invention, and now they were received, not with ecstasies of delight, but with fresh demands, more ridiculous even than the first. They were decidedly being mystified, and were preparing in consequence to pack up and begone, furious, and swearing by all their gods that they would never again expose science to see itself disgraced by a purse-proud vulgarian's scorn; when, lo! happily, a good fairy, the special friend of learned men, came passing by that way. She raised her enchanted wand with the tip of her finger, and all at once a little girl dressed in rags appeared in the midst of our astonished professors. Without giving them time to recover themselves, the child put her hand into the little patched waist of her dress, and drew forth a rounded object, about the size of her closed fist from which hung a quantity of tubes spreading in all directions. "See!" cried she; "here is the machine your banker demands of you." Picture to yourself a small closed bag, narrowing to a point at the end, and separated within into two very distinct compartments by a fleshy partition which went across the inside from the top to the bottom. Such was the object held up by the little girl. Prom each of these compartments issued a thick tube, ramifying into endless smaller ones; and they were moreover each surmounted by a sort of pouch, into which ran another tube, of the same description as the first. Each of these four portions (the two compartments and their pouches) was in constant but independent motion, distending and contracting alternately; and by carefully examining the noiseless play of this singular machine, (the walls of which were, by the magic power of the fairy, rendered transparent to the bystanders,) the learned assembly were very soon enabled to convince themselves, that it fulfilled all the monstrousconditions exacted of them by the fantastic millionaire. All was in movement together, I told you; but let us begin at one end. The right-hand compartment and its pouch represented the first pump; the pump employed to draw, by the same stroke, the water from the stagnant channel, and that from the taps. It was perfectly easy to distinguish the two systems of pipes, and how they united together at the small pouch on their arrival. When this was distended, a vacuum was created inside, which was instantly filled by the liquid from the tube which ran into it, (do not ask me why or how; I will explain that presently). When it contracted again, the liquid which had just entered was not able to get back, being prevented from so doing by a very ingenious and simple contrivance, which requires a brief explanation. Take off the lock from your chamber-door, which opens inside; then, standing outside, push against it with your shoulder, and you will get in without any difficulty. But when you are in, try to push the door open again with your shoulder in order to get outside into the passage, and you will find that you will not be able to pass through, and this simply because it does not open on that side. Which was exactly what happened to the liquid in the pouch! The door between the tube and the pouch only opened inwardly, and the liquid finding itself pressed on all sides in proportion as the pouch contracted more and more, and unable to return, was obliged at last to make its way through another similar door which led to the large compartment below. Here the same game recommenced. The compartment which had distended itself to receive it, contracted in its turn, and the liquid finding the road again barred behind it, had no choice but to force its way through the tube which led to the air-reservoir. Here commenced the work of the second pump,--the pump of the left compartment. The little pouch, when distended, was filled by the liquid from the reservoir, and then forced it forward into the large compartment below, always by means of the same process. This compartment again drove it, by a powerful contraction, into the large conducting tube charged with the office of its general distribution throughout the body. At the end of all which, it returned once more into the right-hand pump as before, to pursue the same course again, &c., &c. Thus, as you see, the whole mechanism turned upon two little points of detail, of the simplest description possible; namely, first, on the entrance-doors only opening on one side; and secondly, on the elastic covers of the pouches and compartments distending and contracting spontaneously. It was the prettiest thing in the world to see this unpretending-looking little bag working thus, quite naturally, without a suspicion that it was solving a problem which so many men, proud of their science, had given up as hopeless. Certainly here was a machine which made no noise! Once installed in its dark closet, it would have been necessary to place your hand upon it to find out that it moved at all. My lord could certainly sleep beside it without disturbance. "How much do you want for it?" said they to the poor little beggar girl. "Name your price; have no fear; we will pay you anything you wish." "I cannot give it to you," replied the child; "I need it too much myself: IT IS MY HEART. Now that you have seen it, make another like it, if you can." And she disappeared. It is said that the engineer, who longed to see his idea carried out, tried hard to construct a similar machine with gutta-percha and iron wires, and to set it in motion by electricity. But history does not tell us that he succeeded, and we have yet to ask ourselves whether the richest man in the world, aided by the wisest men in the world, could ever provide himself with a miracle of wonder, such as the, ragged child had received as a free gift from the hands of a gracious Creator. LETTER XIV. THE ARTERIES. If you have thoroughly understood the story I last told you, my child, it will have revealed to you the whole mystery of the _circulation of the blood,_ and you are at the present moment wiser than all the learned men of antiquity and the middle ages, for they had none of them the faintest surmise of the truth. It may, perhaps, seem odd to you that men should have existed for upwards of five thousand years without making inquiry into a matter which so closely concerned them, and which was so easy to find out. Is it not almost incredible that so many hearts should have beaten for so long a period without any of their owners having felt a wish to know exactly _why?_ Yet so it is. The action of the heart and the flow of the blood have not been understood for much more than two hundred years, and the man whose name is attached to this great discovery richly deserves that we should say a few words about him. He was called Harvey. He was an Englishman; physician to King Charles I., who was beheaded in 1648; and when he first ventured publicly to teach that the blood was constantly circulating from one end of the human body to the other, perpetually returning and retracing its steps, a great scandal was created in the world. He was called a fool,--an impertinent innovator,--a madman. His words shattered old doctrines, and he only received for his reward all the petty annoyances which men are apt to lavish so freely upon any one who tells them something new; because--do you see?--it is so disagreeable to be disturbed in one's habits and preconceived ideas. Harvey is not the only one in the history of mankind who has committed the sin of being right in defiance of the opinions of his age. It is true posterity takes account afterwards of the labors of genius, and inscribes a fresh name upon her list. But one must pay for this glory in one's lifetime. One cannot have everything at once. This is an old story, my child, but always new nevertheless; and for my own part it is, I own, one of my pleasures to amuse myself by reflecting how much cause for laughter three-fourths of the great men of the present day are providing for the little girls who shall be alive two centuries hence. Time is a great avenger, and puts many things and men in their proper places. Let us pause here a moment while we are speaking of Harvey. I should be curious to know what any one of the courtiers of Charles I., bedecked in feathers, ribbons and laces, would have said to the valet who would have placed the excellent Harvey, with his insane invention, above his most gracious majesty, the lord and king of all Great Britain! And yet what is his most gracious majesty to you to-day? What do you owe to him? in what does he interest you? While you can never hear the name of Harvey pronounced without remembering that you are under many obligations to him! A thousand years hence, when society shall have made the great progress which may reasonably be expected, the name of Harvey will be familiar to every one who owns a heart, while that of Charles I. will be only a vanished shadow; a souvenir lost in the maze of history. Our debt of remembrance paid, let us return to the heart--the little closed bag which labors so prettily. We must now inquire the real names of whatever has figured in our story. The two great compartments are called _ventricles,_ the two small pouches _auricles,_ and they are also distinguished as being on the right or left side;--_right ventricle, left ventricle, right auricle, left auricle._ The inner doors on which depends all the action of the machine, are called _valvelets._ By-and-bye, when the pump and the steam-engine are explained to you, you will meet again with these treacherous doors, which never allow what has once entered to go back again; but then we shall call them _valves._ The air-reservoir, I need scarcely tell you, is the _lung,_ to which the blood goes to put itself in contact with the air. The subterranean watercourse, of which I hope we have talked long enough, is _the small intestine,_ in which the _chyle_ collects; and the tubes which run into it are, of course, the _chyliferous vessels,_ the only channels by which anything reaches the heart which has not previously gone out from it. The tubes of distribution, which run out from the machine in all directions, are called with us _arteries_; the return tubes, which bring back the water to the machine, are called _veins._ Finally, we have not exactly the _filters_ employed to clear the water from the impurities contracted as it goes along, for no such thing exists in us. There are in our case the refuse-chambers of which I have already spoken, in connexion with the liver, where the blood disembarrasses itself of any useless materials, and from which it comes out with clean pockets, so to speak, reverting to the comparison of which we have already availed ourselves. As you see, then, everything comes round again; and the bright idea which our professors hit upon in order to satisfy the caprice of the banker is exactly carried out in your own body, only a thousand times more perfectly than could have been done by them all, even with all their science added to all his money. I mentioned that the shrewdest of the party boasted about making an artificial heart. But, let me tell you, there is one thing I would have defied him to imitate, by any expedient he could devise, and that is the inimitable construction of the _arteries_ and _veins,_ and the incomprehensible delicacy of their innumerable ramifications. Let us talk a little about these marvellous tubes, and begin with the arteries, which have the most important part to play. Did you ever see a doctor try the pulse of his patient? Take hold of your own wrist and search a little above the thumb. You will soon find the place and feel something beating against your finger. There is an artery which passes there, and the little beating you feel is the rebound of the pulsations, of your heart. Every time that the left _ventricle,_ by contracting itself, chases the blood into the arteries, these, of which the tissue is very elastic, become distended all at once, and then contract again, repeating the process whenever a fresh gush of blood arrives, so that their movement is exactly regulated by the movement of the heart. It is true the two movements are in a contrary direction; that is to say, the artery becomes distended, while the heart contracts, and contracts when the heart enlarges itself; but that makes no difference to the doctor. What he wants to know is, with what force and rapidity the heart of the patient beats, and I will explain why. It is an interesting point in the history of circulation. When you were very little--very little indeed, my dear child--your heart beat from 130 to 140 times in a minute. Afterwards the beats sank to 100 per minute; then to fewer still. At present I cannot tell you the precise number: perhaps, about ninety. When you are a grown-up young lady, it will beat about eighty times in the minute; when you are a mother, about seventy-three times; when a grandmother (if such a blessing be granted you), only from fifty to sixty times, perhaps even fewer. People tell of an old man of eighty-four whose heart beat only twenty-nine times in the sixty seconds. Observe that in all my calculations I have taken special care to prefix the word _about_ to the numbers mentioned. And this because, in point of fact, the heart is a capricious creature, which has no exact rules to go by. It changes its pace on every occasion--fear, joy, every emotion which agitates the soul, quickens or retards its movements; and derangements of health may be detected by its pulsations, which are infinitely varied in character. In fever, for instance, which is nothing but a race of the blood at full speed, the hearts of grown-up people beat as quickly as those of little children; sometimes, indeed, more quickly still. In certain maladies it goes with great sudden leaps, like a galloping horse; in others it trots in little jerks; while in some cases it moves slowly and wearily, and its throbs are so weak that one can scarcely feel them. These pulsations, then, afford important revelations to the doctor. The heart is for him a gossiping confidant, who lets out the secrets of illnesses, however closely they may fancy themselves hidden in the remote depths of the body. When the doctor lays his finger on the patient's pulse, it is precisely the same thing to him as if he had laid it on his heart, only with this difference, that the one is much less difficult to do, and much sooner done than the other. The artery of the wrist is in fact a small heart, not only because it follows all the movements of the large one, but because it carries forward the work which the other begins, and assists also in propelling the blood to the furthest extremities of the limbs, driving it on in its turn at each of its own contractions. Imagine a fire-engine, whose pipes should take up and drive forwards along their whole length the water which is thrown upon the fire, and you will have some idea of the marvellous machine which is at work in our behalf within us. Nor are you to suppose that the wrist-artery is a specially privileged one, because it has been chosen to hold intercourse with physicians. All the others are equally serviceable; and if they cannot all be used for "feeling the pulse," it is because they are generally more deeply buried in the flesh, where it is not easy to reach them. Observe your mother when she is packing a trunk, and you will see that whatever she is most afraid maybe spoiled, she is most careful to put in the middle, so that it may be least exposed to accidents. And this is what a kind Providence has done with the arteries, which have the utmost cause to dread accidents; whilst the veins, which are much better able to bear rough usage, are allowed to wander about freely just under the skin. But when the bones happen to take up a great deal of room, and come near the skin themselves, as is the case in the wrist, the artery is forced, whether he likes it or not, to venture to the surface, and then we are able to put our fingers upon him. And there are others in the same sort of situation; the artery of the foot for instance. But only just think how far from agreeable it would be to have to take off your shoe and present your foot to the doctor! The artery which passes to the temple, just by the ear, is another affair. That would answer the purpose very well in fact, and I even advise you to make use of it when you want to feel your own pulse. It is more easily found than the other even, and its pulsations are still more easily perceptible. Nevertheless, when all is said and done, it is better for the doctor to take his patient by the hand than by the head. Merely as a matter of good manners. I will now make you acquainted with the principal arteries, and the manner in which they distribute the blood through the body. The whole of the blood driven out by the left ventricle at each of its contractions, passes into one large canal called the _aorta_. The _aorta_ as it goes away at first ascends; then bends back in a curve; and from this curve, which is called the _arch of the aorta_ (from its shape) diverge right and left, certain branch-pipes which carry the blood into the two arms and on each side of the head; and which are, in fact, the beginning, or upper end, of those whose pulsations we feel with our fingers in the two wrists and at the temples. The supply to the upper part of the body being secured, the _aorta_ begins to descend. But now imagine of what importance it must be, that this head-artery--the foster-father of the whole body--should be sheltered from every accident. The _aorta_ once divided, death is inevitable; you might as well have your head cut off at once; and thus it has been fixed in the best--that is to say, the safest--place. Of course you know what is meant by the _backbone_ or _spine_, called also the _vertebral column_, in consequence of its being made like a sort of column composed of a series of small bones fastened together, which are named _vertebræ_. Touch it and feel how solid it is, and how few dangers there can be for anything placed behind it. Well, that is the rampart which has been given to the _Aorta_. As this descends, it slips behind the heart and takes up its place in front of the _vertebral column_ which it follows all the way down the back, just to the top of the loins. There it is, so to speak, almost unassailable; in fact hardly any cases are known of the _Aorta_ being wounded; to get at it, it would be necessary to bestow one of those blows which used to be given in the time of the Crusades, which cut the body in two. There was an end of the _Aorta_, as of every thing else then; it was unfortunately not worth talking about any longer! The next time you see a fish on the table, ask to be shown the large central bone. It is the fish's _vertebral column_, and it will give you an idea of your own, for it is constructed on the same plan. You will perceive a blackish thread running all along it--that is _the aorta_. As it descends, the _aorta_ sends off on its passage a great number of arteries which carry the blood into all parts of the body. Arrived at the loins it forms a fork; dividing into two great branches, which continue their descent, one on each side the body, down to the very extremities of the two feet. As you perceive, dear child, this is not very difficult to remember. A large fork, whose two points are at the tips of the feet, the handle of which curves at the top like the crook of a crozier; from this curve come four branches, which pass into the two arms and to the two sides of the head--and this is the whole story. But of course, it would be another affair were I to enter into the detail of all the ramifications. Here it is that all engineers, past, present, and future, are baffled, defeated and outdone! Choose any place you please upon your body, and run the finest needle you can find into it what will issue from the puncture? "Thanks for the proposal," you say; "I have no occasion to try the experiment, to discover that blood will come out." You say that very readily, young lady; but have you ever asked yourself, what is implied by your being so sure before hand that you can bring blood from any part of your body if you choose to prick it, though never so slightly? It implies that there is not on your whole frame a spot the size of a needle's point, which has not its own little canal filled with blood; for if there were such a one, there at any rate the needle would pass in without tearing the canal, and causing the blood to flow out. And now count the number of places from the top to the bottom of your dear little self, on which one could put the point of a needle, and even when you have counted them all, do not fancy you have arrived at the number of the tiny tubes of blood. Compared to these, your needle is a coarse stake, and tears not one but a thousand of these little tubes in its passage. That seems to you rather a strong expression, does it not? But let me make good my boldness. A needle's point is very fine, I admit; but a person who could not see it without spectacles must have very poor sight. Whereas the last subdivisions of the blood-tubes are so attenuated, that the best eyes in the world, your own included, cannot distinguish them. You are astonished at this, and yet it is nothing compared to what follows. No doubt you have heard of the microscope,--that wonderful instrument by which you may see objects a thousand, a hundred thousand, a million times, if necessary, larger than they really are. With the microscope, therefore, as a matter of course, we can see a good many of those tiny canals which elude our unaided sight. But, alas! we discover at the same time that these are by no means the last subdivisions. The canals invisible to our naked eyes subdivide themselves again into others, and these into others again, and so it goes on, till at last--the man at the microscope can see no more, but the subdivisions still continue. You were ready to exclaim, at my talking of thousands of canals being torn by a needle in passing through; but had I even said millions, it may be doubted whether I should have spoken the whole truth. Besides, when you consider the office of the blood, you can easily understand that if there were a single atom of the body left unvisited by him, that atom could never be nourished. Do I say nourished? I have made here a supposition altogether inadmissible; it could have no existence at all, since it is the blood only which produces it. These imperceptible canals of blood have been called _capillaries_, from the Latin word, _capillus_, which means a hair; because the old learned men, who had no suspicion of the wonders hereafter to be revealed by the microscope, could think of no better way of expressing their delicacy, than by comparing them to hairs. Very likely they thought even this a great compliment, but your delicate fair hairs, fine as they are, are absolute cables--and coarse cables too, believe me, compared to the _capillary vessels_ which extend to every portion of your body. Observe further, that each of these arterial _capillaries_ is necessarily composed (being the continuation of the large ones) of three coats enclosed one within the other, which can be perfectly distinguished in arteries of a tolerable size; add to this that within these coats there is blood, and in the blood some thirty substances we know of, not to speak of those we do not know; and then you will begin to form some notion of the marvels collected together in each poor little morsel of your body, however minute a one you may picture to yourself. LETTER XV. THE NOURISHMENT OF THE ORGANS. When I said formerly that our dear and wonderful steward the blood, was everywhere at once, you little suspected the prodigies involved in that _everywhere_. But you will have a glimpse of them now, when I tell you it is at the extremities of the _capillary arteries_ that he carries on his distribution of goods, and accomplishes a mysterious act of nutrition; a wonder much greater even than that of which we have just spoken. Here, indeed, the question is no longer mechanical divisions, whose delicacy, surprising as it may be, is yet within our powers of comprehension. What is more surprising still, what moreover we cannot comprehend at all, is the delicate sensitiveness of tact--I would almost say of instinct--with which each one of the million millions of tiny atoms of which our body is composed, draws out of the blood--the common food of all--exactly that aliment which is necessary to it, leaving the rest to his neighbor, and this without ever making a mistake. You have never thought about this; for children go on living at their ease, as if it was the simplest thing in the world to do; never suspecting even that their life is a continued miracle, and never, of course, therefore, feeling bound to be grateful to the Author of that miracle. And alas! how many hundreds of people live and die children in that respect. But what would happen, I should like to know, if the eye took to seizing upon the food of the nail, if the hairs stopped on the way what was intended for the muscles, if the tongue absorbed what ought to go to the teeth, and the teeth what ought to go to the tongue! Yet what prevents their doing so? Can you tell me? They all drink alike out of the same cup. The same blood goes to furnish them all. The substances that it brings to the eye are the same as those which it brings to the nail; and nevertheless the eye takes from it that which makes an eye, and the nail that which makes a nail. How is this done, do you think? that is the question. When the doctors reply to this, that each organ has its peculiar sensibility, which makes it recognize and imbibe from the blood one particular substance and no other, they are strangely mistaken if they flatter themselves that they have really answered anything. They have done nothing but reproduce the question in other words, for it is precisely that sensibility which requires explanation, and to tell us that it exists, does not explain much, you must own. If you were to ask why you had got a headache, and some one were to reply that it was because your head ached, you would not be much the wiser I fancy. Each of our organs, then, may be considered as a distinct being, having its separate life, and its particular likings. These organs behave towards the blood like men who recognize some friend in a crowd, and proceed to seize him by the arm; and when I told you just now that they never made a mistake, I spoke of their regular course of action in ordinary circumstances. Like men, they also make mistakes sometimes, in certain cases; and take one substance for another, or do not recognize the one they are in need of; an unanswerable proof that at other times they exercise a sort of discernment, and do not act by a sort of fatality, as one might be tempted to believe. Look at the bones, for instance. They are composed of _gelatine_ (which cooks serve up under the name of meat-jelly, but which would be more properly called bone-jelly), and of phosphate of lime, a kind of stone of which we have spoken before, if I remember rightly, and from which they get all their solidity. Originally, the substance of the bone is entirely gelatinous, and the phosphate of lime deposits itself therein by degrees, as time goes on, and always in greater abundance as we advance in age. Properly the bones borrow only gelatine and phosphate of lime from the blood. But when they come to be broken, their texture or _tissue_ inflames in the fractured place; and then it changes its tastes, if I may so express myself; and, lo and behold, extracts from the blood that which forms certain little fleshy shoots, which unite together from the two sides of the fracture, and so mend the broken bone. Here is one exception to the rule. Again, in certain diseases, the bones suddenly quarrel with the phosphate of lime; they will not hear of it any longer, they will not accept a fresh supply; and as the old wears out by degrees, by reason of the continual destruction of which I spoke the other day, the bones become more and more enfeebled, and soon can no longer support the body. A second exception this. Finally, when old age comes on, the bones end by being so much encumbered with phosphate of lime, that they have no room to admit the fresh supply which keeps coming to them in the blood. What becomes of it then? It goes to seek its fortune elsewhere; and there are charitable souls, who forgetting their instinctive antipathies, consent to give it hospitality, though much to the prejudice of the poor old man himself, who is no longer served so well as formerly, by the incautious servants who have allowed themselves to be thus fatally beguiled; but no one consults him. It is the arteries especially, and sometimes the muscles, which take this great liberty, and it is not unusual among old people to meet with these fairly _ossified_--that is to say, changed into bone, thanks to the phosphate of lime with which they have consented to burden themselves. This is a third exception, and I will spare you any others. What may we infer from all this, my dear child? Well, two things. First, that we know nothing at all about the whole affair; a fact which at once places us on a footing with the most learned philosophers in the world. Secondly, that our body is a perpetual miracle; a miracle which eats and drinks and walks, and which we must not look down upon for so doing: for God dwells therein. I should have to come back to this at every turn, if I wanted to fathom everything I have to tell you about. Each tip of hair which you grow, is an incomprehensible prodigy which would puzzle us for ever, if we did not call to our aid those eternal laws which have made us what we are, and to which it is very just our spirits should submit, since we could not exist for one second were they to cease from making themselves obeyed in our bodies. Reflect on this, my dear little pupil. Young as you may be, you can already understand from it, that there is above you something which demands your respect. The good God, to whom your mother makes you pray every night, on your knees, with folded hands, is not so far off as you might perhaps suppose. He is not a being of the fancy, secluded in the depths of that unknown space which men call Heaven, in order to give it a name. If His all-powerful hand reaches thus into the innermost recesses of your body, His voice speaks also in your heart, and to what it says you must listen. LETTER XVI. THE ORGANS. Contrary to my custom, my dear child, I made use, in the last chapter, of a new word, without giving an explanation of it. I spoke to you of _our organs_, and we have not yet ascertained what an _organ_ is. You probably knew what I meant, because it is a word which is used in conversation and pretty well understood by everybody. But I am bent upon giving you a more exact idea of it, for the trouble will be well bestowed. If I did not do this at once it was because there is a good deal to tell about, and that would have carried me too far away from my subject. _Organ_, comes from the Greek word _organon_, and means _instrument_. It was used particularly to signify instruments of music, so much so that our word "organ" comes from it. Our bodily organs then, are _instruments_, or _tools_ if you like it better, which have been given to us, wherewith to perform all the acts of life; and as there is not one part of the body which is not of use to us for some purpose or other, our body is, in point of fact, from head to foot a compound of _organs_. Thus the hand is the tool which we make use of to lay hold of anything--so an _organ_; the eye is the instrument of sight--so an _organ_; the heart is the machine which causes the blood to circulate--so an organ; the liver fabricates the bile--it is an organ therefore; the bones are the framework which support the weight of the body--so organs; the muscles are the power which sets the bones in movement--organs also, therefore; the skin is the armor which protects them--so an organ: in fact everything within us is an organ. If there was any corner of our body which was not an organ, it would be useless to us, and we should not, therefore, have received it, because God makes nothing without a use. Here lies the secret of that great miracle which is called life. I do not know whether you will be able to understand me thoroughly, but open your ears, as if some one was going to explain addition to you; this is not more difficult. Life is in reality the total of an addition sum. Each one of our organs is a distinct being which has its particular nature and special office; its separate life consequently; and our individual life is the sum total of all these lesser lives, independent one of the other, but which nevertheless blend together by a mysterious combination, into one common life, which is everywhere and nowhere at the same time. It follows from this, that the more organs a being has, the greater is the sum total; the more, consequently, is life developed in him. Remember this when we begin to study life in the lower animals. In proportion as you find the number of _organs_ diminish, you will find life diminishing in power, until we arrive at beings who have, as it were, only one organ apparent, and whose life is so insignificant, that we have some difficulty in giving an account of it, and are saying the utmost that can be said in calling it life at all. But this comparison of life to the total of an addition sum, is too dry; and, although it has its appropriate side, yet it might give you a false idea of life; which is what always happens when one tries to solve inscrutable questions and hidden mysteries by a matter-of-fact illustration. Let us try for something more to the purpose. I told you that the Greek word _organon_ was applied especially to instruments of music. Well, let us consider our organs as so many musical instruments. You have, probably, sometimes been at a concert. Each of the instruments in the orchestra performs its own part, does it not? The little flute pipes through all its holes; the double-bass pours thunder from its chords: the violin sighs with his; the cymbals clash; the Chinese bells dance to their own tinkling; all go at it in their own fashion, each independently of the other. And yet, when the orchestra is in good tune together, and well played, you hear but one sound; and to you the result of all these various noises, each of which would have no meaning alone, is music composed by some great artist whom you do not see. It is no longer a flute, a double-bass, or a violin which you hoar; it is a symphony of Beethoven's, an oratorio of Haydn's, or Mozart's overture to _Don Juan_. Life is just like this. All the instruments are playing together, and there is but one music; music written by God. But wait! when I say _life is just like this_, let us come to an understanding. Life is _some_thing like it, that is all, for as to telling you what life is, I shall not attempt it. I know nothing about it, do you see, though that is a painful confession to have to make to a pupil; but in this case it does not distress me, and you are welcome to hunt the world through for a master, who in this matter does know anything. I could make a hundred other comparisons, but theywould all fail in some point or other. Shall I tell you where this one fails? In an orchestra there is always a musician by the side of the instrument. Now with us we see the instrument well enough, but we cannot see the musician. You are inclined to ask me, perhaps, why I am wasting so much paper to-day in talking to you about organs, instead of going on tranquilly with our little history of the circulation. But I told you just now that the secret of life lies in the organs, and before entering upon the history of life, I ought to have begun with them. It is there all the books begin which treat of the subject we are studying together, and if you had one in your hands at this moment, it would teach you that all creatures whatsoever are divided into those which have organs and those which have none--that is, into _organic_ and _inorganic_ beings [Footnote: A lump of iron is the same throughout. Each of its parts has the same properties and the same uses. It has no organs, it is an _inorganic_ being. A rose tree has flowers, which are differently made from its leaves, and serve a different use: a root which sucks up the precious food of the earth; a bark which is of a different nature from the wood, and serves a different purpose. It has organs; it is an _organic being_: all animals and vegetables are _organic beings_.] (_in_ stands here for _not_, as _in_complete means not complete). This is, in fact, the starting point for the study of nature, and there are many other things besides which I ought to have told you before I began. But we went straight ahead, without looking at what we were leaving behind, satisfied with turning aside from time to time to pay our debts. And while I am making my confession, I ought to tell you all. You would probably only have listened to me with half an ear, if I had begun at the beginning. There is a proverb which says--"The appetite comes with eating." I do not advise you to follow this proverb too closely at dinner, for it might mislead you sadly. But it is always true when applied to learning; it is what one knows already that gives one a taste for learning more. If I have been making you bite at the organs to-day, which is rather a tough morsel, it was because I fancied that your appetite had begun to come. Was I wrong? Let us now return to the blood which nourishes the organs. LETTER XVII. ARTERIAL AND VENOUS BLOOD. It is at the extremity of the capillary arteries, as we have said, that the incomprehensible prodigy of the nourishment of our organs is accomplished. This done, the next thing is for the blood to return to its starting-point; and here recommence those infinitesimally minute wonders of which we have already spoken. Close upon the capillary _arteries_ follow the capillary _veins_, equally fine and imperceptible as the others. These take possession of the blood everywhere at once, without allowing it a moment's respite, and it is thenceforth on its road of return, travelling back again to the heart. Where do the veins begin? where do the arteries end? No one can say precisely, since the last ramifications of each elude the eye of man, however much it may be aided by the admirable instruments which his genius has invented. Nevertheless, although no one has ever ascertained the fact by sight, there is one thing I can tell you--namely, that our minute veins are a continuation of our minute arteries, and that it is the same canal which as it lengthens out turns from an artery into a vein, without any interruption; the substances destined for the nourishment of the organs passing through its walls, as moisture passes through our skin when we perspire. But if nobody has seen this, say you, how can they know it for a fact? Let me explain. In man, and in the animals which come nearest to man in structure, it has never been seen; but it has been seen elsewhere. This requires a little explanation, and you will not regret my giving it hereafter. It has its interest, I assure you. When you put your hand on your throat, how does it feel to you? _Warm_, does it not? And when you take hold of a kitten or a bird, how do they feel? _warm_ in the same way. Now, then, can you tell me whence comes this warmth? But to save time I will answer the question myself. It comes from their and your _blood_, which is itself warm, and we shall soon see why. You have no idea of all the curious facts wrapt up in that little phrase, "You are warm-blooded;" your blood is warm. But it has not got warm of itself; bear that well in mind. Now if you touch a frog, a lizard, or a fish, how do they feel to you? Cold, of course, you answer. But I ask why? A question you will answer in the same way as the other. Because their blood is cold, they are "cold-blooded." Precisely; and while you are about it you may add that, if their blood be cold, it is because it has not been warmed as yours is. Do not be impatient, we shall make all this clear at the proper time and place. Now in the cold-blooded animals, such as serpents, frogs, tortoises, lizards, fishes, and others, the blood circulates as it does in us, and what is more, it does so, thanks to a machinery very similar to our own. But, as you may imagine, a machine which produces warmth must be constructed in a more perfect manner than a machine which produces no warmth; and to speak truth, without flattering you, there is a little difference between you and a frog, and it seems natural enough that the body of a frog should be more clumsy in structure than yours. It is the old story of the poor man being not so well lodged as the rich; but putting aside rich and poor, who are all human beings alike, let us take one of those lovely dolls who walk, and move their arms and head, and say papa! and mamma! and compare it with a cheap bazaar doll which you can get for a penny. Both are made, in the main, in one way. Each has two arms, two legs, a mouth, a nose, eyes, &c.; but what a difference in the details of the two! and what infinitely more pains have been bestowed on one than on the other! Well, cold-blooded animals are, so to speak, _penny doll_ animals, by comparison with ourselves. Like us they have arteries and veins, but there is not near so much workmanship in them; and that marvellous delicacy of the capillary extremities, which in man and in the warm-blooded animals drives the close observer to despair, does not exist to trouble us in these others. It is true that with the naked eye we are still unable to see everything, even in them; but with the help of the microscope the whole is laid open to us--the extremities of the arteries and the extremities of the veins; and it was here that what I was telling you of, just now, was observed and discovered,--namely, that the end of the artery changes into a vein, without any interruption in the tube. It was these very observations upon fishes and frogs, which eventually gained the day in favor of Harvey's ideas on the circulation of the blood, at which the learned men of his own age had laughed so much. He was dead by that time it is true, as has happened but too often in such cases, but do not let us pity him too much! He who has had the rare good-fortune to lay hold of a new truth, and launch it into the world, is sufficiently recompensed in advance. If he also craves after the flattering voice of man's approbation, and the toylike pleasure of personal triumph, he is after all but a child, unworthy of the great part God has given him the privilege of playing. A child, did I say? Then how rude you must have thought me, dear child! And as a punishment, you are perhaps going to remind me that I have once more fallen into my old bad habit of wandering away from my subject. Never mind, I am going to return to it at once. How can one distinguish--you will ask me--an artery from a vein, so as to be able to determine which is a vein and which an artery? In many ways, I reply. First of all, an artery, as I told you lately, is composed of three coats, of which the principal, _i.e._. the inner one, is tough and elastic, whereby the artery is enabled to force the blood forward in its turn, but which is also the reason of arterial cuts being so dangerous; for in such cases the wounded tube remains wide open; being held so by the stiffer inner coat; and thus the blood is allowed to run out indefinitely. Now this inner coat is wanting in the veins, whose walls sink in together when a cut is made in them, so that it is much easier to stop the flow of the blood in them. Furthermore, the veins are furnished inside at intervals with little doors, similar to those we noticed at the entrance of the _auricles_ and _ventricles_ of the heart. You remember those important _valvelets_, on which depends so much of the mechanism; which permit the blood to pass in one direction, but will not allow it to return back in the other?--well, the little doors of the veins, which are also called _valvelets_, do exactly the same work. They open in the direction of the heart, to allow the blood to pass on, but it finds them fast closed if it wants to go back; so that as soon as it has forced one passage there is no longer any hope of its return, and thus by degrees it gets nearer and nearer to the heart without any possibility of escape. There is nothing similar to this in the arteries, which the blood traverses in a single bound from the impetus it receives from the heart. Finally--and this is most important--the blood which is found in the veins is no longer the same as that which fills the heart. No longer the same? you exclaim--have we then two sorts of blood in our bodies? Most certainly, my dear child; but you would not have suspected it; for when you accidentally prick or cut yourself, or when your nose bleeds, it is always the same sort of blood that comes out--that fine red liquid which everybody knows so well by sight. This is because the blood flows at once from the small arteries and small veins, and what you see is a mixture of the two. The same mixture issues from all wounds, whether small or great, and on this account people are unanimous in declaring that blood is red; a statement which is not true of either arterial or venous blood, separately. The last is black, as you might convince yourself if you had courage enough, and should happen to be in the room with any one who was going to be bled,--a rare event, happily, in these enlightened days. In such a case it is always a vein which is opened, the reason of which you will understand, after what I said of the danger of cutting the arteries. You would there, fore see a reddish black jet of liquid spout from under the lancet; much blacker than red, however--that is _venous_ blood. When, on the other band, an artery has been accidentally cut, what comes out is quite different. It is a rosy, frothy fluid, almost like milk and carmine dissolved in it, which has been whipped up with a stick; this is called _arterial_ blood. Nothing is more simple, as you perceive, than to distinguish an artery from a vein; you have only to ascertain what is inside of it. When the blood goes out to our organs to nourish them, it is _arterial_; when it is returning back after having nourished them, it has become _venous_. But what--you will ask--is it going to do now at the heart, towards which it is on its road? It is going to seek there a fresh impetus which shall send it once more into the lungs, where it will again become _arterial_, _i. e._ and once more capable of affording nourishment to the organs. Therein lies the whole secret, and the why and the wherefore of the CIRCULATION. This is easily said, dear child; but suppose that you do not comprehend it? Well, you need not be ashamed. There is no possibility of comprehending it until one has learnt what RESPIRATION is--so here we are stopped short. To-morrow, then, when we will begin with the study of this third part of the History of Nutrition; and if the first two have amused you, I feel pretty sure you will not find this last one dull. LETTER XVIII. ATMOSPHERIC PRESSURE. When we have been laboring very hard, my dear child, and want to rest for a minute, we say, _Let us take breath_; because breathing is an action which takes place of itself, requiring neither effort nor attention on our part. But, if it takes place of itself, it does not explain itself; consequently, when I say to you, _Now, let us take breath_, this is not a signal for my having a rest, for I have undertaken to explain Respiration to you. If you were a German, I would remind you of what so often happens when you put a fork into a dish of sour-krout. You want to lay hold of a little bit merely, but the strips of cabbage-leaf are twisted one within the other, and hang together in spite of you, so that withoutintending it you get hold of a whole plateful at once. Now this Respiration affair is something like the sour-krout story--begging your pardon for the comparison. I should have liked to give you only a small plateful--a child's plateful--of it; but I feel the explanations coming, hanging one upon the other; and, whether I will or no, I must treat you like a grown-up person, and we must give up for once the nice little doll's dinners with which we began. In my opinion, you will lose nothing by the change if you will but pay attention; for about that soft little breath of yours, which is always coming and going over your pretty lips, there are many more things to be learnt than you have heard of yet. As I said just now, you will find you have got hold of a plateful all at once. A good appetite to you! To prevent confusion we will divide the subject into two parts. I shall explain to you first, _How we breathe?_--a very curious question, as you will see. And afterwards we will examine, _Why we breathe?_--which is still more interesting. First, I must tell you that air is heavy, and very heavy too; a thousand times more so than you may suppose. The air we breathe, through which we move backwards and forwards, that air is _some_thing, remember, although we do not see it; and when there is a wind, that is to say, when the air is in motion, like a stream of water running down a hill, we are forced to acknowledge its being something, for we see it throw down the largest trees and carry along the biggest ships. But without going so far out of the way for examples, try--you who run so well--to run for two minutes against a strong wind: and then you shall tell me whether the air is something or nothing. But if it be something it must have weight, for all substances have; paper as well as lead; with this sole difference, that the weight of lead is greater in proportion to its size than that of paper. Now a sheet of paper is very light, is it not? and you would be puzzled perhaps to say what it weighs. But many sheets of paper placed one upon the other, end by forming a thick book which has its undeniable weight; and if some one were to heap upon your head a pile of large books, like those you see on your papa's shelves, the end might be that you would be crushed to death. In the same way, a small amount of air is by no means heavy; but you can conceive that a great quantity of it gathered together may end by weighing a great deal. Now get well into your head the fact, that we, here, on the surface of the earth, are at the bottom of an immense mass of air, extending to somewhere about forty or fifty miles above our heads. Let us say forty to make more sure, for learned men have not yet been able to calculate the precise height to a nicety; and for my own part, I think we have done wonders to get so near the mark even as this. But can you picture to yourself the distance which forty miles high really is? I will help you to form some idea. One mile contains 5,280 feet, and your papa is six feet high. One mile high would therefore be 880 times as high as your papa, But this is a mere nothing--only one mile's height. In forty miles there would be no less than 211,200 feet; and setting papas aside, of whom it would take 35,200, one on the top of the other, to go so far into the sky, let us think of the height of the tallest buildings you know; church and cathedral towers for instance. Now the towers of many parish churches are 150 feet high; the towers of York Minister not 300. At that rate it would take 1,408 ordinary parish church-towers, or upwards of 704 York Minster towers, piled one above the other, to reach to the end of the forty miles of air above our heads. I leave you to judge what would be the weight of a mass of paper piled up as high as that. You may safely grant then, that this mass or pile, or if you like it better, this _column_ of air (for that is the proper expression), must be of considerable weight; as is still further made certain by the fact of its having been weighed, so that I can even name the weight to you if you wish to hear it. Bear in mind too, that the weight of a column of air will be in proportion to its _superficial extent_--to its breadth and width, that is; for, as you may suppose, a column as large in extent as one of the towers of York Minster will weigh a good deal more than one the size of a single brick. But wait; here is a book on the table which will serve me for a measure, and as you will probably find the same on your mamma's table, you can follow my measurement. It is a French Grammar. The back is seven inches long and four and a quarter wide. That is, there are four and a quarter rows, each seven inches long. In other words, the back contains nearly--and let us call it quite, for convenience' sake--thirty inches side by side. Thirty _square inches_ as it is called. Measure your mamma's copy and you will see. Now, can you guess the weight of the column of air forty miles high which this volume supports? Upwards of four cwt.; 450 lbs., that is to say. If you want to be very exact, here is the rule. Air presses on all bodies at the rate of fifteen pounds to every square inch; so now you can make the calculation for yourself. But I suspect you had no idea you were so strong; for I see you tossing up the book, heavily laden as it is, like a feather. Comfort yourself. There is no magic in the matter. If a very strong man were to push you on one side, could you resist him? Certainly not. But if another man of equal strength were to push you at the same time on the other side, what would happen? Well, you would remain quietly in your place, without troubling yourself more about one than the other, the two forces mutually destroying each other. And this is the case here. While the air above your book is weighing down upon it with a force of 450 lbs., the air below it presses against it underneath with an equal weight, and this destroys the effect of the other. From 450 lbs. take 450 lbs., and nothing remains. Your grammar has nothing to carry after all, and you may toss it about as you please, without deserving much credit for the effort. "What are you telling me?" you inquire. "If I put a stone on the top of my head, I can feel its weight easily enough; but if I put my hand on the top of the stone I no longer feel anything. How can the air below the stone press against it? And talking of columns--how pleasant it would be, for instance, if the people who go up the Monument were to have the weight of it on their heads when they get to the top!" Well said, little one. And your objection reminds me of an argument which distracted my head as a lad, when I first heard the pressure of air explained by a good fellow who did not trouble himself to be quite as exact as you and I are in our discussions. I was told that the surface of the body, or the skin of a large man, measured sixteen feet square, which is equal to the surface of a table four feet long and four broad. Now, you know that in four feet there are forty-eight inches, and on the surface of the table are forty-eight rows, with forty-eight inches in each, or 2,304 square inches; so that a man's surface is 2,304 square inches, and the weight his body supports is 34,560 lbs., or upwards of fifteen tons--always at the rate of fifteen pounds to every square inch, you understand. Now, I was constantly asking myself how it happened that in entering a house one never seemed to get rid of this almost fabulous weight, since the roof of the house must naturally interpose itself between the air-column of forty miles high and the man who would then only have some few feet of air above his head. The roof would support the rest, that was clear. From whence, then, came the 34,560 lbs. which seemed to weigh as heavily as before; since, whether on the threshold of the door, while still under shelter of the roof, or two steps outside in the open air, under the tremendous column forty miles high, one never felt a bit lighter, not even to the extent of the weight of a single sheet of paper? This was a difficulty from which I could never extricate myself. I found out the answer to the riddle afterwards, and a very simple one it is. Air does not, in point of fact, _weigh down_ like a solid fifty pounds' weight, which has no impulse but to descend, and has nothing to do with anything above it. It _presses against_ rather, like a spring, which, having been compressed, tries to resume its natural position with a force equal to that which holds it back. Ask some one to show you the spring of a watch, and you will understand this better. Each atom of air is a spring of matchless elasticity, which nothing can break, which never wears out, which one can always compress, if one employs force sufficient, and which is always ready to expand indefinitely, in proportion as the compressing power is withdrawn. Now, consider the column of air outside the door, where there is a pile of such springs forty miles high. The lower ones have to bear up all their comrades, which press upon them with their united weight, and these make desperate efforts to repulse the tremendous pressure, and to spread out in their turn. They endeavor to escape in every direction--to the right, to the left, above, below; but caught between the earth, which will not give way, and the compact mass of all the columns of air which surrounds the earth in every direction, and of which the lower part is equally compressed everywhere, they struggle unceasingly, but in vain; indefatigable, but powerless. You live in the midst of those little wrestlers, and naturally bear the punishment of the injury done to them. They press against you as against every thing else--before, behind, on all sides--with a force equal to thatwith which they are themselves compressed, or I would say, equal to the weight by which they are so horribly squeezed and contracted: so that, in fact, you bear this weight not only on your head and shoulders, as you might at first suppose, but also all along your body and limbs, under your arms, under your chin, in the hollow of your nostrils, everywhere. Now we will suppose you to enter the house; and what do you find there? Outer air, which on its part has got in by the door, the window, and every little crevice in the wall. The column outside the roof no longer presses upon it, but what is the gain of that? It was compressed when it got in, and the little springs will struggle as a matter of course, quite as much on this side of the door as on the other. The protecting roof has so little power that were it not itself protected by the air outside, the pressure of which keeps it in its place, the air within would shiver it into a thousand fragments in its efforts to get loose. You laugh; but wait till I explain myself further. I will take the case of a miniature house to make the matter pleasanter to you; one fifteen feet long, fifteen feet wide, and with a flat roof, the most economical plan as regards space. Fifteen feet are five yards, and as the multiplication table tells us that five times five make twenty-five, our roof will in this case be twenty-five square yards (_i. e._ 225 square feet) in superficial extent, or _area_; it is not much, and you will find few as small. Would you like to calculate the force with which the millions and thousand millions of little spring imps imprisoned under that poor unfortunate roof would press against it? We settled before that the quantity of them brought to bear upon a square inch had the power to push at the rate of fifteen pounds. Were they to push against a square yard (a surface 1296 times greater than the square inch) it would therefore be 19,440 lbs. This being so for one square yard, calculate for twenty-five square yards, and you will have the amount of pressure against our roof--viz. 486,000 lbs--merely that! And now tell me what cottage roof in the world was ever built so as to be able to stand against such a weight? Perhaps though, you can scarcely appreciate the amount of heaviness, 486,000 lbs. Well, 486,000 lbs. is nearly 217 tons; and one of those railway trucks that you see laden with coals at the stations can carry, perhaps, from eight to ten tons, without breaking down. Say ten tons as an outside estimate, and then think of piling the contents of twenty-one such trucks on your roof, and yet you would still be short of the weight of air which is bearing down upon it. I need scarcely say now that were you to take away the air from within the roof, theair without would smash both it and the whole cottage flat, as a giant at a fair strikes an egg flat with one blow of his fist. To show you how in another way: take a moderate sized column or pillar, such as you see sometimes in a nobleman's grounds, of about the weight of the twenty-one tons, and set it up like a chimney on the roof of our cottage, then walk away to a little distance and watch what will happen! There, little Miss Laugher! have you at last learned to value the weight of the air, or _atmospheric pressure_ as it is more properly called; since it is the force with which the atmosphere presses against rather than weighs upon everything on the surface of the globe? It is no joke, as you perceive, and it affords plenty of subject forreflection. I have still to prove to you that I have not been making fun of you with my calculations, and that the weight of air upon a square inch is really what I have said--viz., fifteen pounds. Now, there is a very simple way by which we might get to know your strength, and tell its amount in figures, if one chose; namely, by putting a weight on your arms--a heap of books, if you please--and keep adding and adding to it, until those poor little arms were unable to bear any more. Then weighing what they had borne, whether we should find it to be ten or thirty pounds--I cannot guess how much it might be at this distance--one might safely say, without fear of mistake, "The strength of this young lady is equal to ten, twenty, or thirty pounds"--in other words, "she represents a weight of ten, twenty, or thirty pounds" and by a similar plan people have ascertained the strength of the air--that is, the weight which it represents. They have weighed what it is capable of carrying. I told you lately that the whole surface of the earth was covered by an immense army of little imps--otherwise called little air-springs, which, compressed by the giant mass of their comrades above, all of whom they have to carry on their backs, are always trying to protect themselves, by pushing back everything which comes across them. Imagine the bottom of a well. Our imps are permanently installed there as a matter of course, and face to face with the water they push against it, each one doing his best, on all points at once. As the pressure is equal everywhere therefore, and always the same, there are no signs of it to be seen. Now insert in the water the end of a tube closed below by a cork which exactly fits the interior, but which can be moved up and down in the tube by means of a bar of iron or wood which runs through it. This is called a _piston_, I may as well tell you as we go on. When the piston rises in the tube, it drives before it, as it goes, the air which was already there; and which cannot slip away down the sides because the piston fits so closely to them all the way along. The result of this is, that just underneath the piston there is a place in the water to which the air cannot reach, and at that place the water has no pressure upon it at all. Now see what happens. Pressed upon heavily by the air in every other part and place, like a mouse hunted by a cat, who finds at last a hole through which to escape, the poor water darts at this and ascends the tube close after the piston. So far so good; but if the tube is very long, and the piston rises rather high;--at thirty-three or thirty-four feet above the level of the water it has to continue its ascent alone. The water parts company, stopping quietly behind, half-way up the tube. "What is the meaning of this?" you will ask. It means that the force which presses on the well-water all round the tube, and thus drives it up, has done all it can, and that our little air-imps refuse to supply any more. The water which rises in the tube has a weight of its own of course, and with this weight it presses, as it is fair it should, on the water below. In proportion as the piston rises, the column of water which follows it gets bigger and bigger, and naturally its weight increases at the same time. At last there comes a moment when this weight becomes such that its pressure on the water below is equal to that with which the air-imps are pressing on the water in the well. Thenceforth they may push as they please; no more water will go up. They are in the same position now that they were before, when their comrades (afterwards driven out by the piston) were pressing upon the same point, which had only a moment's freedom; and this water column of thirty-three or thirty-four feet holds them in check, to exactly the same extent as the gay fellows whose place it has taken. Nothing is easier now than to calculate, even to a few grains almost, the force of the pressure of air. One can get at the weight of water, thank goodness! and it has been ascertained that our water-column will weigh fifteen pounds if the tube is a square inch in size. You will comprehend after this that it might be any size you may please to imagine, without there being the slightest alteration in the height of the column. The larger it is, the heavier will be the column of water on the one hand; but on the other, the greater will be the number of air-imps turned out; so it comes to the same thing in the end. If you should feel any doubt about the correctness of this reasoning, you have only to try the experiment over again, in a well, filled with mercury for instance. Ask to be shown some pure mercury, which is also called _Quicksilver_, because one wants to express melted silver, apt to be constantly on the move; it is often to be met with in houses. Mercury weighs thirteen and a half times more than water: according to our calculations, therefore, it would take thirteen and a half times less of it than of water to bring our little air-imps to reason. And this is just what you will find happens; you will see the column of mercury stop short exactly at the moment when it has attained the orthodox weight of fifteen pounds; that is to say, at a height of twenty-eight inches. On the other hand, take some ether. You know that delicate spirit, which smells so strong, which makes your hand feel cold if it is put upon it, and which we give to sick people to inhale. Ether weighs one-quarter less than water. In a well of ether you would therefore see something quite different, and your column would rise without being asked, to something like forty-three feet, exactly up to the point of weighing--like the others--fifteen pounds to every square inch. Air will not be replaced with less. That, then, is the measure of its strength, or our scales are deceitful. LETTER XIX. THE ACTION OF THE LUNGS. I hope I have told you enough, my dear child, to enable you fully to estimate the force with which air presses upon everything on the surface of the earth, and consequently upon our own bodies among the rest. If you understand this, nothing is easier than to understand how air comes and goes in our lungs. When the cook wants to light her fire with two or three hot coals, what does she do? She takes the bellows and blows it, does she not? But if she has no bellows at hand, what does she do? You answer at once, she blows it herself with all the strength of her lungs. By which it would seem--does it not?--that we are a sort of living bellows, being able, in case of necessity, to act as a substitute for the wood and leather ones of common use. And if we really possess the power of doing the work of a bellows, may not this be because we have within us some little machine of the nature of a bellows? Exactly; and this fact gives me the opportunity of making you understand the action of the lungs by explaining that of the bellows, which is in everybody's hands, but which three-fourths of the people use, without troubling themselves to inquire how it is made or acts. "A bellows, as you know, is composed of two pieces of board, capable of being separated and brought together again at will, and united by a piece of leather so shaped and arranged that it doubles up when the boards close, the intermediate space forming a firmly-closed box, the size of which increases or diminishes at every movement of the boards. "We take the bellows down to use it, and there are the boards, lying flat upon each other, the box between them quite small. Is there anything inside, do you think? "Nothing," you answer; "the bellows is empty." Do you think so really, my child? Do you think a tumbler is empty, then, when you have drunk out its contents; and that jelly pots are empty when all the jelly is eaten? There are not so many empty things in the world, I assure you, as you suppose. You forget the air--that monster who is always wanting to stretch himself out, and pushes against everything he meets. He is an unceremonious gentleman, who takes possession of every vacant place; as fast as you put a spoonful on your plate, he takes up the room of the jelly which has been removed, and at each mouthful you swallow, he slips into the place of the water which goes away. When you think the glass and pot are empty, they are, in reality, full of air. You cannot see it; but it is there, you may rely upon it. There is air, then, in the bellows-box, because there is air in every place where there is nothing else to dispute possession with it. The quantity is small in this case, no doubt, because the box is small and cannot hold much. But now, look! I separate the boards, and the box, which was small, becomes large. For once, then, here is a box which must be partially empty; for it has just, as if by magic, made a space in itself in which positively there cannot be anything, since there was nothing there beforehand. Ay! but look down at the centre of the upper board. You see a little hole there, do you not, and below the little hole a small piece of leather, which seems to close it up? That is a _valve_, one of those doors, such as we noticed before in the heart, and such as are to be found, moreover, in most houses, which let people through on one side but not on the other. This one opens when it is pushed from without, but lets nothing out which has once got in. Now, the air outside, as I said before, is always pushing against everything. He pushes as a matter of course, therefore, against the valve, and as there is nothing behind it to resist the pressure, in proportion as room is made inside the box, he enters and fills it with himself. But presently some one begins to close the bellows, and he finds himself caught between the boards; on which these invite him to begone, with the same sort of politeness displayed by the police, when the hour of departure comes in a place of public exhibition; when, _i.e._, they spread out on all sides, and force the crowd before them till they have found the road to the door. But the air cannot get back by the way it came in, the door being shut. As, however, it must go out somewhere, whether it likes it or not, it passes through the tube at the end of the box (the _nozzle_ of the bellows), and comes out thence with a rush upon the fire. When it is once gone the bellows can be distended again, and the process be repeated as before indefinitely. And this is just what goes on inside ourselves. Your chest, my child, is a box which expands and contracts alternately; making a place for the air by the first effort, and then driving it out by the second. It is neither more nor less than a bellows, but of a simpler construction than that used by the cook. The exit pipe serves also for a door of entrance, and there is but one board instead of two. The _exit pipe_ is the _larynx_, of which we spoke before, when we were talking of swallowing the wrong way, and which communicates with the air outside, through the nose and mouth at the same time, allowing us to breathe through either one or the other as we like. As to the _board_, I said a few words about it when I was describing the liver. It is the _diaphragm_--that separating partition--that floor which is placed between the two stories or divisions of the body--the belly and the chest. But here especially the infinite superiority of the works of God over the miserable inventions of man comes out in all its grandeur. A bellows which was to have the honor of keeping up within us that miraculous fire--the pre-eminently sacred fire--which we call Life, required something more than a common board for its foundation. And accordingly this, of which I am now going to give you a detailed history, is as marvellous as it is admirable. I fancy that when you have read my account, you will no longer turn up your nose at the vile word _diaphragm_. Let us first take a peep at the construction of the bellows. On each side of the _vertebral column_, from the neck to the loins, spring twelve long bones, one below the other, bent in the form of bows; these are called the _ribs_. The first seven pairs of ribs rest, and as it were, unite, in front, upon a bone called the _sternum_, which you can trace with your finger down to the pit of the stomach, at which point the finger sinks in, for there is no more _sternum_, and the last five ribs on each side no longer unite with those of the opposite one. For which reason they are called _false ribs_. On the other hand they are joined to each other at the ends by means of a strip or band of a substance sufficiently strong, but at the same time flexible, and somewhat elastic, which is called _cartilage_ or _gristle_. The next time you see a roasting piece of veal on the table, look well at it, and you will see at the end a white substance which crackles under your teeth; that is _gristle_. This forms the framework of our bellows, which you may picture to yourself as a kind of cage, widening towards the bottom and going to a point at the top, for the arches formed by the upper ribs are smaller than the others. The whole terminates in a sort of ring, through which pass, together, the _oesophagus_ and the _trachea_. The space between the ribs is occupied by muscles which reach from one to the other, and the whole framework or cage is shut in below by the _diaphragm_, that marvellous board whose history I have promised to relate. The _diaphragm_, as I told you some time ago, is a large muscle, thin and flat, stretched like a cloth between the chest and the _abdomen_. It is fastened by an infinity of little threads called _fibres_, to the lower edge of the cage I have just been describing, and it looks at first sight as if it must be incapable of moving, since it is fixed in one invariable manner all round the body. It moves nevertheless, but not in the same way as the boards of our bellows. Ask your brother to hold two corners of your pocket-handkerchief; take hold of the other two yourself, and turn the handkerchief so as to face the wind. The four corners remain in their place, do they not? but the middle, inflated by the wind, curves and swells out in front like a ship's sail, which itself is only an immense hand kerchief after all. Then draw the handkerchief tightly towards you, each to your own side, and it will recover itself and become flat again. Loosen it a little and it will curve and swell out again in the middle, and this maneuver you can go through as often as you choose. Which very maneuver the _diaphragm_ is continually performing, of and by itself. In its natural position it bulges upwards in the middle, like a cloth swollen out by the wind, and thus occupies a portion of the chest at the expense of the lungs. When air has to be admitted, its _fibres_ tighten and bring it flat again, as you and your brother brought the handkerchief flat just now by tightening it. The whole space previously occupied by the arch of the _diaphragm_ is thus given up to the lungs, which, being elastic, instantly stretch themselves out to it; while air, running in through the nose and mouth, fills up in proportion the empty place (_vacuum_) created by the extension of the lungs, exactly as in the case of the bellows. But soon the fibres of the _diaphragm_ relax. It rises up again into its old position, driving back the lungs as it does so; and the air finding there is now no room for it, goes out by the same way the other came in. I say _the other_, observe, because the air that goes out is no longer the same as when it came in; and this is the secret of _why we breathe_; while the up and down movement of the _diaphragm_ is the explanation of _how we breathe_. As you perceive, then, the mechanism of these bellows of ours, is of the most simple, and consequently of the most ingenious character, and leaves far behind it anything we have ever imagined. Are you disappointed? Do you feel inclined to exclaim, "Is this all?" to ask where are the wonders I promised you? to protest that I may talk as I please about the inflating and flattening of a pocket-handkerchief? _you_ can see nothing so marvellous in the matter; nothing worth making your mouth water for. A little patience, Mademoiselle! Hitherto we have talked only of the machine; but there is a goblin inside it, and our fairy tale is going to begin again. There are in some families certain old servants who belong to the house, more, it may be said, than their masters, in some ways. They educate the children, and they serve them till death; they live for them alone, and know so well what they have to do, both by day and night, that there is no need to give them any orders. Nay, not only is it unnecessary to give them directions--it is for the most part labor in vain. They are so completely at home in their business, that they will go nobody's way but their own. If you wish them to alter their habits they may obey you for an instant, but it is only to return into the old groove directly after; for they know better than you do what you want. I was very little when I first read in the story-books of my day, some bitter complaints of the disappearance of this race of old-fashioned servants of the good old times. And you very likely may have seen it said that they are no longer to be met with. Yet there will always be some, depend upon it, in families, who know how to make and to keep them. Good old times or not, they have never been found in any other but these cases. Still, _I_ have just such a one as I have described--even I who am talking to you--and so has your mamma; and what is more, you have one yourself; and what is more still, everybody else has one. This servant of the good old times, who will never disappear (and this is more than one can promise of any other) is the _Diaphragm!_ When you came into the world, my dear child, and were merely a poor little lump of flesh, without strength, intelligence, or will; incapable of giving any orders whatever to those organs of yours, of whose existence you were not even aware, your _diaphragm_ quietly began his duties, without leave or inquiry from you, and with your first _breath_ your life began. Since which he has always gone on, whether you attended to him or not, and his last effort will be your last sigh. When you go to sleep, careless of all that is to happen, until you awake again, that servant of yours, indefatigable at his post, labors for you still, and the light breath which half opens your rosy little lips as it passes through them; that light breath which your happy mother watches with such pleasure, is his work. Midnight strikes--one o'clock--two; all around you are buried in sleep--but he is awake still. Were it otherwise--were he to go to sleep when you do, you would never awake again! This protector of each instant, this faithful guardian of your life, is, nevertheless, subject to you as a servant to his master. Attend to him, and he will obey your orders. You can make him go at a great pace, or slowly, as you choose; or stop him altogether, if the fancy takes you to do so: but this not for long. The servant of the good old times is obstinate in the performance of his duties. He will yield to you in trifles; but do not try to force him over serious matters. I have read somewhere of a desperate young fellow, chained down in a dungeon, who killed himself by holding his breath; but I never quite believed it. Mr. Diaphragm would not allow any one to carry rebellion so far as that. But we have not finished yet, and you do not yet know how appropriate is the comparison I am making. Should any misfortune, any grief, any trifling annoyance even, befall his master, a good servant suffers with him, and as much as he does; sometimes even more. Occasionally the master is comforted, while he remains still disturbed. "And the diaphragm?" you ask. The diaphragm does precisely the same, my dear child. Yours, especially, shares in all your griefs to such an extent that, truth to say, he is not always quite reasonable. The other day when your mamma did not want to take you into the country with her, he was so sorry for you that he went into perfect convulsions, and you sobbed and sobbed till she was obliged to say, "Come, then, you naughty child;" whereupon you embraced your mamma, and were quite happy again, while he remained still unappeased, and your poor little chest was shaken more than once afterwards by his last convulsions. Sobbing, you must know, is merely a convulsion--a great shake of the diaphragm--which is the reason of its causing such a heaving of the chest. It is the same with respect to joy. The joy of the master makes the servant dance, and so the diaphragm too! Its little internal jumps are, then, what we call laughter--a thing you are well acquainted with. Put your hand on your chest next time you laugh (and I hope it will be soon) and you will feel how it dances--thanks to the diaphragm which jumps for joy whenever it finds you in good humor. Please to observe further, that nothing of all this is done to order. He starts of himself, poor fellow, without waiting to ask if you will ever know anything about it; and, in truth, you have known nothing about it up to the present moment. What say you to the diaphragm now, my child? Does not the very name please you? You scarcely expected to find there--under your lungs--so good a servant, one so attached to your person, so strongly resembling in all points the best specimens we know among men. And still we have not done. I have reserved as a finale for you a new point of resemblance which will make you open your eyes very wide indeed. The old servant is sometimes cross and grumbling. If anything is going against his grain in the house he has no scruple in saying so; and his mode of speaking is sometimes rather rude. Nor is it of any use to get impatient and impose silence on him; he will listen to nothing--it is his privilege. But let some unforeseen accident happen to his master, let him see him deeply affected, and in a moment all his anger is over. He sets himself silently to work again, recalled to order twenty times sooner by his master's emotion than by his utmost impatience. You ask what I am coming to now? My dear child, what I have just told you is the history of the _hiccup_--the history of the hiccup, neither more nor less. I must first tell you, however, that the _diaphragm_ keeps up intimate relations with his neighbor below--the stomach. Every time he rises in the breast the stomach rises behind him; and not only the stomach, but also its companions, the intestines. All the officials employed in the business of digestion travel regularly with him; coming down as well as going up in company. Put your hand upon your abdomen and breathe strongly and you will feel the rebound of all the movements of the diaphragm. Now, when matters are going on wrongly inside, when too much work has been imposed on the officials, or work they dislike, or else when they have been disturbed in their labors, it will sometimes happen that the _diaphragm_ takes part with his comrades in the abdomen. He gets angry then, and shakes his master, who cannot help himself a bit. You must be very well acquainted with these attacks, which are very fatiguing when they last long. One begs pardon and resists him in vain; he does as he pleases, without stopping to listen, turning everything upside down; and do you know the only efficacious plan for calming him at once? It was a constant source of wonder to me when I was little. A sudden fright, a start unexpectedly caused by a friendly hand slipping secretly behind, and laying hold of one, was all-sufficient; disarmed by the agitation you have undergone, the naughty, stubborn muscle forgives you, and you are cured. Having dwelt so long on the truly wonderful resemblance between the proceedings of two sorts of beings, whom no one that I know of ever thought of comparing together before, I will now, my dear child, give you the key to all these comparisons, which seem so whimsical at first, but are so striking in reality, and which come to my pen of their own accord, as it were, in the midst of the explanations I have undertaken to give you. Many people who would not themselves care for them, will declare that they are too hard for a little girl to follow. But for my own part, I find that the eye can take in a mountain as easily as a fly, and that it is not more difficult to lay hold of great ideas than of little ones. It is short-sighted people, not children, who cannot see far before them. Who made the heavens and the earth? God, your catechism tells you. The same God made both; did he not? We do not acknowledge two. And if it be the self-same God who made everything, the hand of the universal Maker will be found everywhere; and from the highest to the lowest portion of His work the same mind will manifest itself under a thousand different forms. Not only, either, is each man separately, one by one, the work of God. The whole human race, taken in the mass, is also His creation; and the laws by which human society--that great body of the human race--seeks to regulate itself for the preservation of its existence, are undoubtedly the same as those which overruled the organization of our individual bodies. It is not very astonishing, then, if we find, in the life of human society around us, details corresponding with each detail of the life of the human body, or, at any rate, closely resembling them. What would really be astonishing, would be that mankind as a whole should be differently constituted from man as an individual, and that human society should have other appointed conditions of well-being than those of each of its members. So, while I am on the subject, I should like to advise those who wishto apply themselves to what is called _politics_--that is to say, social life--to begin their studies of the body social, by studying the body human, first. They will learn more from it than from the newspapers! But you have nothing to do with all this. For the present, take notice of one thing only; viz., that the hand of the same God has passed over everything, and that there is neither much presumption nor much merit in tracing points of comparison between the different parts of His work. These comparisons are not a mere play of the mind; they really exist ready made in the very foundations of things. Now let us come down a little from these heights and return to our friends the lungs. I have not spoken about them for some time, and I have not yet told you how they are constructed. I wish I could show you some, but the cook will do so, if you would like to see them. The _lights_ with which she feeds the cat and the dog are the lungs of some animal. Take up a piece in your hand, and you will find you have got hold of something _light_ (cooks have not given it its name without a reason), which is also soft, sinks under your finger if you press it, and rises again afterwards like a sponge. In fact, the lung, like the sponge, is composed of an infinity of minute cells, whose elastic sides can be contracted or expanded at will. They are like so many little chambers, into every one of which blood and air keep running hastily, each on its own side, to bid good day to each other, touch hands, and then hurry out as briskly as they came in. Whether the bit of lights the cat is eating, comes from an ox, a pig, or a sheep, you may look at it with perfect confidence; your own lung is precisely like it. You would see nothing different, could you look into your own chest. So much for the _substance_ of the lungs. As to SHAPE, imagine two large, elongated packets, flat inside, descending right and left, inside the breast, and bearing the heart, suspended between the two, in the middle. The extremity of each packet descends below the heart, and it is in the interval which separates them that the arch of the diaphragm performs its up and down movement. I have already said that air reaches the lungs through the _larynx_. The _larynx_ (of which we shall speak further when I have explained another curious thing very valuable to little girls--the voice), the _larynx_ is a tube composed of five pieces of _cartilage_ (you know now what _cartilage_ or _gristle_ is), the firm resisting texture of which keeps it always open. After these five pieces of _cartilage_, come others, and the tube is continued; but it then takes the name of the _trachea_; the _larynx_ and _trachea_ constituting the _windpipe_. At its entrance into the chest, the _trachea_ divides into two branches, which are called _bronchial tubes_, and which run, one into the right lung, the other into the left. You sometimes hear people talking about _bronchitis_. It is an inflammation of these _bronchial tubes_, which are within an inch or two of the lungs. It is necessary, therefore, to be very careful in such circumstances, and do exactly what the doctor prescribes, because--one step further, and the inflammation extends from the bronchial tubes into the lungs themselves, with which it is not safe to play tricks. Having reached the lungs, the _bronchial tubes_ subdivide into branches, which ramify again in their turn like the boughs of a tree, and the whole ramification terminates in imperceptible little tubes, each of which comes out in one of those little chambers I was talking about just now. And this is the way in which air gets there at all. The venous blood which leaves the heart, arrives on its side by one large canal, which passes out from the right ventricle, and which is called the _pulmonary artery_. And, to tell you the truth, while there is no learned man present to be angry with us, it is a very ill-chosen name, because it is _venous_ blood which flows in this so-called _artery_. But the doctors have decided that all the vessels which run from the heart should be called _arteries_, and all those which go back to it _veins_, whatever may be the nature of the blood which they contain. We cannot help it, because they manage all these matters in their own way; but in that case it was scarcely worth their while to talk about _arterial_ and _venous_ blood. It would have been better to have said simply, red blood and black blood. Be this as it may, _venous blood_ arrives from the right _ventricle_ through the _pulmonary artery_. This divides itself, like the _bronchial tubes_, into thousands of little pipes, whose extremities come creeping along the partitions of the little chambers in question. And here, then, takes place, between the air and the blood, that mysterious intercourse for the account of which I have kept you waiting so long; and at the end of which the black blood becomes red, or, in other words, from venous becomes arterial. I have called it "intercourse," and this is really the proper phrase; for this transformation of the blood is accomplished by means of an exchange. The air gives something to the blood, and the blood gives something to the air--each giving, in exchange, like two people over a bargain in the marketplace. With your permission, my dear child, we will stop here to-day. We have now got to the charcoal market, and it is a little black. LETTER XX. CARBON AND OXYGEN. Here, then, my dear child, we have arrived at the explanation of that great mystery, WHY _we breathe._ Keep on the alert, for we are now entering into a region where everything will be new to you. Here we are at the charcoal market, I said to you just now, and no doubt you concluded that I was beginning another comparison. But no such thing; there is no question of comparison or simile here; I state the fact itself, pure and simple as it stands: it is a _market,_ for commercial intercourse and exchange are carried on there, as I told you before, and it is a _charcoal_ market, because _charcoal_ is, positively, the essential and chief article of commerce. You are astonished, I dare say, and are ready to ask me whether I can possibly mean real charcoal, charcoal such as the cook puts into the furnace. Surely, say you, we have nothing like _that_ in our bodies? Surely we don't eat _that_? But I answer yes; real, true charcoal, and you do not dislike it; you eat of it even daily; nay, you do not swallow a single mouthful of food which does not contain its proportion of charcoal. You laugh; but wait a little and listen. When you are toasting a slice of bread for breakfast, and hold it too near the fire, what happens to it? It turns quite black, does it not? When mutton-chops are left too long unturned on the gridiron, what happens to them? They turn quite black also. When your brother forgets the apples which he has set to roast, what happens to them? They turn quite black, as you have seen more than once. It is always black, then, that these things turn, is it not? and a fine rich _charcoaly_ black, as you may see if you please to observe charcoal closely, for just such is the color of little burnt cakes, over-roasted chestnuts, and potatoes in their skins, which have been dropped into the fire. But there is a common term by which we can express more accurately the misfortune which has befallen all these various things--slices of bread, mutton-chops, apples, cakes, chestnuts, potatoes, and what-not, when "burnt," "over-toasted," "over-roasted," or "over-baked." We may call them _carbonized_, or more simply _charred_ or _charcoaled_; though the word _charred_ is generally used only for burnt _wood_. But _carbon_ being the principal ingredient of _charcoal_, and _charcoal_ being one of the purer forms in which we get at _carbon_, they are almost synonymous terms, and you may call your burnt food _carbonized_, or _charred_, or _charcoaled_, whichever you prefer. The next question is, how did charcoal or carbon get into the food so as to justify our talking of its being _carbonized_ or _charred_? Even when we use charcoal stoves for cooking, the charcoal does not jump out and get into the mutton-chops, etc., you may be sure. Then it is clear it must have been in them before they were brought to the fire to be cooked; and such is indeed the case, only its black face escaped notice because it was in such gay-looking company, and kept itself hid behind the others like a needle lost in a match-box. Set fire to the matches, and you will soon have nothing left but the needle, which will then strike your eye at once. And so with our burnt food; the fire has carried off all the other ingredients, and the charcoal is left behind alone, exposed to everybody's view, as if on purpose to teach them that it was always there; in the apples, i.e., the potatoes, mutton-chops, etc., which seemed so tempting when the black rogue was hid, but from which now, when he is there by himself, they turn away in disgust. Charcoal is, in fact, a much more generally distributed substance than you have been used to suppose, dear child. That which comes from burnt wood is most easily observed, because there is a much larger proportion of charcoal in wood than anywhere else; but there is not a morsel, however small, of any animal or vegetable whatsoever, which does not contain charcoal. In the sugar which you crunch, in the wine which you drink, there is charcoal. I could even find some in the water you wash in if I were to try hard. There is charcoal in the goose-quill which I hold in my hand at this moment, and in the paper on which I am writing, and in the handkerchief on my knee. If I hold them all three in the light of my wax taper, I shall soon see them turn black and betray the presence of our friend. It exists in the wax taper itself, as also in the candle, as also in the oil lamp. If I were to hold a piece of flat glass above their flame, I should collect enough of it to blacken the tip of anybody's nose who presumed to doubt the fact. There is a portion of it in the air; a portion of it in the earth. Where is it not? In short, all the stones of all the buildings in the world are filled with it from top to bottom. _Charcoal,_ under his more scientific and important name of _carbon,_ may be called one of the great lords of the world. His domain is so extensive that one might go round the world without getting out of it; he is even worse than the Marquis of Carabas. After this you will never, I hope, want to persuade me you do not eatcharcoal; for, indeed, you would be puzzled to escape doing so. Of all the things you see on the dinner-table there is but one in which you will not find it--viz., the salt-cellar; and even while saying this, I mean only, in the _salt_ itself, for as to the salt-cellar, clear and transparent as its glass may be, there is charcoal in it! Our bodies, therefore, are full of charcoal. Everything that we eat supplies them with enormous quantities of it, which take up their quarters in every corner of our organs. It is one of the principal materials of the vast collection of structures of which I spoke to you in the early part of these letters, and of which the blood, the steward of the body, is the universal master-builder. If you remember, I told you then that these structures fell to pieces of themselves, in proportion as the workmen went on building, and that the blood, which brings fresh materials on its arrival from the lungs and heart, carries away the refuse ones on its return. And, of all these refuse materials, old charcoal is one of those which takes up the most room, as fresh charcoal took up a great deal of room in the new materials. The blood, as he goes back again, has his pockets quite crammed with it, and if he did not try hard to get rid of it as fast as possible, he would be disabled from being of any further use. Now it is in the lungs that he clears himself of it. He gives it up to the air, which has need of it for a very interesting operation, of which I shall tell you more by and bye; and in return the air gives him something which is quite indispensable to him, for without it he would not dare to return to the organs, as his authority would no longer be recognised. In the same way, the charcoal-seller goes to market with his charcoal and receives silver in exchange. If he were to go home without money his wife would receive him with abuse. But what is the indispensable thing which the blood obtains in his marketing? Remember its name well: it is OXYGEN. And we must speak of it with respect, for we are talking here of a very great and powerful personage, very superior even to CARBON. If CARBON be one of the great lords of the world, OXYGEN is its king. There is a certain substance, my dear child, of which many people, especially little girls, do not even know the name, but which yet constitutes of itself alone a good half of everything we are acquainted with in the world. And this substance is the very thing I have just named to you. It is OXYGEN. Ascend into the air as high as you can go, viz., to forty miles or so from the ground, as we said before; _oxygen_ forms the fifth part of that vast aerial ocean which surrounds the globe on every side. There it is free--is _itself_--if I may use the expression; it is in the condition of _gas_; that is to say, it eludes our sight, though there is no difficulty in ascertaining its presence, when one knows how to set about it. Go down into the depths of the sea. People think they have good reasons for believing this to be two and a half miles deep on an average, which would give a pretty little sum total of tons for its whole weight, as you will be convinced, if you take the trouble of observing the space it covers on a map of the world;--to say nothing of lakes, rivers, streams, the water in the clouds, the water scattered throughout the interior or on the surface of continents, including that with which you wash your face every morning. Oxygen enters in the proportion of eight-ninths into the composition of this incalculable mass. _Eight-ninths_, you understand, which is very near being the whole nine; in every nine pounds of water there are eight pounds of oxygen, the remainder being left for another substance, of which we shall have occasion to speak presently, and which is called _hydrogen_. The earth on which you tread is full of oxygen. So far as we have penetrated hitherto into the interior of the globe, we have found king Oxygen everywhere: hidden under a thousand forms, connected with a heap of substances, not one of which could exist without him; imprisoned in a thousand combinations, and always ready to resume his natural condition if his prison-house be destroyed. The whole surface of the earth, plains, hills, mountains, towns, deserts, cultivated fields, everything you would look down upon, if on a clear day you could be carried high enough in a balloon to take in the whole earth at a glance:--all that may be considered as an immense reservoir of oxygen, out of which we should see it escaping in gigantic waves, if some superhuman chemist were to take it into his head to put our poor little globe into a retort of the same kind as chemists use among us. To give you an example; the stones of our fine buildings, in which we have already discovered the presence of _carbon_, are almost half made up of _oxygen_. In a stone which weighs 100 lbs. there are 48 lbs. of oxygen, and the first chemist who passes by could make them come out of it if he chose, if he were to use a little trouble and skill. I enumerated to you last time many of the substances in which _carbon_ is to be found; but as regards _oxygen_ we must give up all attempt at making a list; it would comprehend the whole dictionary. Touch whatever lies under your hand--in your room--in the house--wherever you may go--I will almost defy you to put your finger upon anything--metals excepted--which is not crammed with oxygen. Your very body, to conclude with, would become so small a thing, were the oxygen it contains extracted from it, that you would be perfectly amazed. So when I told you oxygen was king of the world, I did not say too much, did I? Between ourselves too, it is a great misfortune that people live on so complacently in total ignorance of this all-important material, which is connected with everything, which insinuates itself everywhere, which we make use of every instant of our lives, which may almost be said to be in some sort our very selves, since it constitutes three-fourths of our body, but whose name nevertheless would, I am certain, make many pretty little mouths pout, if one were to utter it in a drawing-room. This is really the case. Many young ladies who are proud to know who Caractacus was, would be ashamed to know anything about oxygen. There is a foolish notion that women have no business with such subjects, probably because children are supposed not to breathe and mothers are not required to watch over them? This reminds me that we are on the road to explain _respiration,_ which I had almost forgotten in lifting up this corner of the veil behind which Nature hides her most valuable secrets from the idle and ignorant. It is _oxygen_ then, which the blood carries off triumphantly from his interview with the air in the cells of the lungs; and, by the way, it is, thanks to this oxygen that it returns from the lungs to the heart, and so from the heart to the organs, with that beautiful rosy tint which distinguishes _arterial_ from _venous_ blood. Now the blood gives out this oxygen on its road every time it performs the journey, and the perpetual course it performs from the lungs to the organs, and from the organs to the lungs, has for its chief object the perpetual renovation of this previous provision, which is as perpetually consumed. Do you ask of what use it is? Does the blood leave it at random in our organs, and is it one of the materials with which our steward is constantly providing the little workmen of the body for their various constructions? No, my dear child. The proverb _"One cannot live upon air,"_ is a very true one, although it is equally true that we cannot live without air. Air does not nourish our organs; on the contrary, it consumes them, and what we eat, serves to supply in precisely the same proportion its insatiable appetite. When we leave off eating, from whatever cause, the air does not leave off too. He goes on always just the same, and that is the reason why people who are starved to death are so thin. (The air has consumed the vital parts.) You did not expect this; but now prepare yourself to go on from one surprise to another. To begin with, I shall have to stop here and explain to you before we go any further--can you guess what? Nay, I am sure you cannot; FIRE. There is not much connection, you will say, between _fire_ and _breathing_. But there you are mistaken. It is precisely the same thing, as I will prove to you next time. LETTER XXI. COMBUSTION. Have you never, my dear child, whilst warming your little feet on the hearth in winter-time, asked yourself, _What is fire?_ that great benefactor of man; fire, without which part of the world would be uninhabitable by us during at least a third of the year; fire, without which we could not bake a morsel of bread, and would have to eat our meat raw; fire, which lights up the night for us, and without which we should have to go to bed when the hens go to roost; fire, which subdues metals, and without which we should have neither iron, nor copper, nor silver, nor anything that is manufactured from those materials; fire, without which, in short, human industry could not rise to much higher results than that of the monkey and of the beaver? We are all of us, it is true, so much accustomed to fire that we do not pay much attention to it, and have a sort of persuasion that lucifer matches have existed from all eternity. But the first men, who were nearer neighbors to that great discovery whence all others have originated--the first men treated fire with more respect than we do. It was to them one of the mighty things of the world. The ancient Persians made a god of it, and told how Zoroaster, their prophet, went to seek it in heaven, passing thither from the top of the Himalayas, the highest chain of mountains in the known world. The old Greeks pretended that Prometheus stole it from the gods, to make a present of it to man, which came to nearly the same thing as the Persian account. The Romans had their _sacred fire_, which the celebrated Vestals were bound to keep lighted, on pain of death to whoever should let it go out. At the present day we do not stand upon such ceremonies, but warm our feet at it quite familiarly, without wishing for anything further. But you would see a terrible revolution in the world if some Prometheus reversed were, some fine morning, to steal it from us, and carry it back to its ancient owners. Every branch of human industry would suddenly stop, as if by enchantment, and in the course of a very few years the poor little framework of human society, of which we are now so proud, would totally change its aspect, and the whole world would be turned topsy-turvy. But do not be alarmed; there is no danger of the sort. Fire is not a present once made to man, but liable to be taken away from him at will. It is a law of nature which existed before the human race came into being, and which will doubtless continue to exist when the human race shall have disappeared. The existence of fire is connected in the most intimate way with that of that great king of the world of whom we spoke last time--Oxygen. Fire is the wedding-feast of Oxygen with other substances! When kings are married, what rejoicings there are! what a commotion! what illuminations! It is only right and proper, then, that the king of the world should have rejoicings and illuminations at his weddings also. And they have never been wanting. The rejoicings are the warmth which rejoices us; the illuminations, the flame which gives us light. But man, in his dealings with nature, is an imperious subject, such as few earthly kings are troubled with--happily for them! Whenever he wants warmth and light he forces the king of the world to get married, and then takes advantage of the feast; nothing worse than that. "How so?" you exclaim. "If I want to make a fire with stones or iron, I should never succeed. Is this because oxygen never unites himself with those substances, nor with heaps of others which are equally useless in lighting a fire? Yet you told me that oxygen was to be met with almost everywhere." It is a fair question, my dear child; but my answer is, that what you said last is precisely the reason why all substances are not fit for making fire of. When oxygen is already there, as he is in stones, for instance, the marriage is over--the feast cannot begin again. Kings are like other people in this respect; their weddings are only celebrated once. If you had happened to be present at the moment when oxygen was united to the materials of which stones are composed, you would have seen a feast of which I should like to have heard some news. I was not there myself either; but learned men in these latter days have succeeded in breaking the bonds which united oxygen with the primitive substances in certain fragments of stone, and with these substances thus freed, and consequently able to remarry, they have been enabled to give us, in miniature, the spectacle of the festivities of a fresh wedding. And I can assure you it is enough to make one shudder, to think of the time when such a marriage must have taken place on a large scale. With regard to _iron_ the case is quite different. You have without doubt heard tell of Louis XIV. (of France), that proud king who was called _le Grand_, and who is said to have heard himself compared to the sun, without smiling. It seems that he one day took it into his head to marry, it is difficult to say why, with Madame de Maintenon, the old wife of a poor paralytic poet named Scarron, who, as such, however, was only known by some few farces. Do you suppose that the palace of Versailles was illuminated in honor of this marriage? Not a bit of it. It was a disgraceful marriage, which they were bound to keep secret. The ceremony was conducted mysteriously and without lighting a single candle more than ordinary. I do not pretend to say that oxygen has any of these weaknesses, nor that he is any more partial to marrying with one body more than with another. In the good God's great world, outside of the family of man, they know nothing of our foolish pride, of our little weaknesses. It is nevertheless a fact that this dear monarch has his preferences, and that all his marriages are not made in this fashion. Leave those pretty little scissors of yours, with which you would try in vain to make a fire, outside your window for two or three days, and then observe the dreadful, scaly, red stain which you are sure to find on them afterwards, and which is called _rust._ Have you any idea whence it proceeds? I will tell you. It comes from the oxygen, which has been making one of those cheerless secret marriages with the iron of your scissors. So there have been no pretty sights nor sounds, no lights nor cheerful noises to entertain anybody, and though people may have wished for them ever so much, they have had to do without them. I will tell you the true reason of these marriages _incognito._ It is because oxygen is but feebly attracted by iron, who does not stand so high in his good graces as many other bodies, and so (to continue the joke) he unites slowly and languidly with him, as we may say. Now tell me, when you set fire to a bit of paper, how long does it take to burn? Half a minute, at the utmost, you answer. Very good. And how long does it take to produce that rust-stain, even though it is probably not a hundredth part the size of the paper? Two or three days, is your reply, for so I told you my self. Here is a strange difference indeed; but from it you may discover why you have not seen any signs of rejoicing or illuminations at the iron wedding. These are always in proportion to the quantity of oxygen which is being married at once--and this was--oh, such a slow affair! When the quantity is very small indeed, the festal illuminations are very small indeed too, and in fact escape observation altogether. In the same way that you would not be conscious of little bits of thread laid delicately one after another on your back, whereas you would plainly feel a large sheet, were it to fall on your shoulders. Yet what is the large sheet but a great quantity of little bits of thread? Only in that case they would all come upon you at once, like the marriage illuminations of burning paper. Wait a little longer and we shall finish. What is there, then, in the paper which pleases the oxygen so much that he unites himself to it so readily, and in such large quantities? What is there? Two substances of high degree, who have actually risen to the dignity of a royal alliance, by the important part they play in the world; one of these, charcoal or _carbon_, we know quite well already; the other I have only mentioned to you in connection with water, HYDROGEN. Thanks to gas companies, everybody in these days knows _hydrogen,_ at least by name. But before proceeding, I will just tell you that it is by far the lightest body that is known. It is forty and a half times lighter than air, which is not very heavy itself, although in the mass it has its weight, as we have seen. The true province of hydrogen is water, where it keeps house with oxygen, in proportion of one to eight pounds, as you may remember I stated in my last letter. But beside this, _hydrogen_ and _carbon_ are in a manner inseparable friends, whom one invariably meets side by side in all animal and vegetable substances. In wood, coal, oil, tallow, and spirits of wine; in everything in short that we call _combustibles,_ because the name of _combustion_ has been given to this marriage of oxygen with other bodies, hydrogen and carbon keep themselves shut up very discreetly and very quietly; like two children playing at hide-and-seek. You have sometimes played at hide-and-seek yourself, no doubt? Now, if some naughty child had come behind you with a lighted candle, what would you have done? You would have had to turn out, whether you liked it or not, and be caught. Well! this is what happens to our two friends, when you bring the paper to the fire. The heat forces them out, and the oxygen, which is always at hand, seizes upon them. In a twinkling they are married, and a beautiful flame springs up into the air, which lasts till everything has disappeared. Hydrogen and carbon! These, then, are the two great combustibles, the two parents of fire; and as nature has lavished them upon us in what we may call inexhaustible quantities; when you hear people lamenting and saying that wood is disappearing, that coal is diminishing, and that the human race will end by not knowing how to warm themselves, do not disturb yourself in the least. There is more hydrogen in a bucket of water than is wanted to cook a large dinner. There is as much and more carbon in our stone quarries than in our coal pits, and when all the woods in the world are cut down (which I trust will never be!) do you know what we shall do? Why, we shall take to burning the mountains. The Jura mountains in Switzerland, for instance, (to take the most favorable case) are great masses of carbon, without its ever being visible. Everything depends upon knowing how to make it come out of its hiding place; but that will de done when it is wanted: more difficult matters have been accomplished already. As to oxygen, whether carbon comes to him from a log of wood or from a building stone; whether the hydrogen comes from a candle or a glass of water, is a matter of perfect indifference to him. He only considers persons, not their origin, and marries as willingly in one case as in the other. So we have returned to the subject of _respiration_, on which I always seem to be turning my back; but now the question is, what brings us to it again? And this is the explanation. When the oxygen picked up in the lungs by the blood has traveled with it to the organs, he finds there two well-known friends--hydrogen and carbon. You smile, and exclaim at once, "Then he marries them, does he?" Yes, my dear child; and it is only for that purpose he enters our bodies at all. And this is why I could not make you understand the nature of respiration until I had explained that of fire to you. As I have told you before, it is the same thing. Invite air into your body by the bellows of your chest, or drive it into the fire by the kitchen bellows--it is always king Oxygen whom you are sending to his wedding. LETTER XXII. ANIMAL HEAT. Now, then, we have got hold of the secret of respiration; the _oxygen_ within us unites itself to the _hydrogen_ and _carbon._ And for what purpose, do you suppose? Unquestionably it must be to make a fire, since they never come together without doing so. But what do people make fires for? I ask next. Well! surely to warm themselves, do they not? And this is the history of your body being warm exactly like a dining-room stove, where the oxygen in the air forms an alliance with the hydrogen and carbon of the wood. Nature warms little girls inside, on precisely the same plan by which men warm their houses in winter. Imagine, then, a little stove, furnished with little arms for helping itself out of the wood-basket as it is wanted, and with little legs to run and refill it when it is empty; the fire must be always burning there, and the stove must be always warm. Just such a little stove is your body; your mouth being the little door, by which there constantly enter--not wood, that would hardly be pleasant--but--hydrogen and carbon under the forms of bread, mutton broth, cakes, sweetmeats, and all the good things people have learnt to make with sugar, fat, and flour. There is hydrogen and carbon in everything we eat, as I have already told you; but sugar, fat, flour, and _wine_ are the substances which contain them in the greatest quantities, and consequently they are our best _combustibles._ You are surprised, perhaps, at _wine_ being a combustible; wine, which you think would put out rather than make a fire. And it would. But that is only because in it, what is good for burning is mixed with a great deal of water, which prevents our being able to set it on fire. But if part of this water is withdrawn, you have _brandy,_ which lights easily enough; and if part of the remaining water is withdrawn from the brandy, you have _spirits of wine_, which takes fire more easily still. If you have ever seen a _spirit-of-wine_ lamp, you must know something about this. Judge from that what a fire spirits of wine must make in the body, even when it has a good deal of water with it; for it is right to tell you that your little stove is very superior to the one in the dining-room, and that it hunts out for consumption the smallest portions of combustible matter, in places where the other would be a good deal puzzled to find them. This is not all, however. I have much greater wonders to tell you yet. What should you say to a stove, which, summer or winter, night or day, in rain or sunshine, amid the ice of the pole, or under the sun of the equator, was able to keep itself constantly in the same condition; neither hotter nor colder one minute than another, whether you gave it much or little fuel, at a given moment, and sometimes when you gave it nothing for whole days together? It would be worthy of a fairy tale, would it not? Yet the human body is a stove of this description. But this requires a little explanation. It is rather bold in me, you may think, to assert so freely, that all the year round, from one end of the earth to the other, the human body is never colder nor hotter than mine is, for instance, at this present moment. "Hot" and "cold" is soon said, you argue: but the exact varieties of _more_ or _less_ are not so easy to measure, and especially not easy to remember, with reference to so many bodies, scattered over the face of the whole earth. What may be warmth for one in one case, may not be equal warmth for another; and even supposing that the same individual learned man could go and inspect every part of the globe in succession, how could he possibly recall, while touching the body of a negro in Senegal, in July, the exact amount of animal heat he had found in a Greenland Esquimaux in January? Be content. I should not have settled the question so cavalierly, if people had not discovered an infallible method of estimating accurately, and always in the same manner, the degree of warmth, in other words, the _temperature_ of the body. Let us first see, then, what this method is, though it will oblige us to digress a little; but you are accustomed to that now, surely; and besides, if I were to go straight ahead, you would not be able to follow me. Do you ever recollect being very cold? Let mammas look after their little girls as much as they please, to prevent it, it is sure to happen to every one some day or other. Now does it not seem at those times as if the whole body were contracting itself--and when people are shivering with cold, have they not a shrunk, shrivelled look? When the weather is very hot, on the contrary, our bodies feel as if they were swelling and stretching, and one seems to take up more room than before. This is the case with all bodies. Heat swells, or, as learned people call it, expands, them: cold shrinks or contracts them. Furthermore, _mercury_ is one of the things most susceptible of this action of heat and cold, and we have had recourse to it accordingly, in the construction of the _thermometer_, [Footnote: _Thermometer_ comes from two Greek words: _thermos_, heat; and _metron_, measure. The degrees in the Thermometer about to be described are marked on the _Centigrade_ principle. [Not the one (Fahrenheit) in general use in the United States.]] a very useful instrument, which you will hear spoken of all your life. The _thermometer_, or _heat-measure_, consists of a little hollow ball filled with mercury, out of which rises a small tube of very thin glass, in which the mercury can move up and down. When the thermometer is exposed to heat, the heat causes the mercury to expand, so it goes up the tube; when the thermometer is exposed to cold, the mercury contracts and sinks again. Now suppose you were to melt some ice in the palm of one hand, and try to dip a finger-tip of the other in a saucepan of boiling water; you would find a great difference of temperature between the two, would you not? Which difference of temperature people have succeeded in measuring with the thermometer, as accurately as your mamma measures a piece of cloth with her yard measure. This is how it is done: You surround the ball of mercury with pounded ice, and while it is melting make a mark at that point in the tube where the mercury has stopped in its descent. Then plunge the thermometer into boiling water. Whereupon the mercury goes up, up, up, till at last it reaches a point beyond which it will not pass. Here a second mark is made, and the space between the two marks is divided into a hundred perfectly equal parts, indicated by so many small lines, which are called _degrees_. But this word _degrees_ has a double meaning in some languages. It means _steps_ as well as the degrees of measurement we are talking about; steps being, as you know, the perfectly equal parts into which a staircase is divided. Fancy the mercury-tube a staircase, then, rising from the cellar where the melting ice is, up to the garret where the boiling water is, and let it consist of 100 steps. The mercury goes up and down this staircase, according as the temperature it encounters approaches that of the boiling water or of the melting ice; and if you wish to know exactly how far it is from the cellar or from the garret, you have only to count the _steps_. Hence arise those expressions which you so often hear--high temperature and low temperature. These mean, temperature according to which the mercury goes up or down this staircase. On the actual floor of the cellar where the ice melts, there are yet no degrees (a floor is not a _step_, you know), so there you find the word _zero_, which means a cipher or nought. Then you begin to count 1, 2, 3, 4 degrees, marked by lines up to 100, where you reach the garret, _i.e._ the boiling-water height. Of course, if the thermometer be exposed to an amount of cold greater than that of melting ice, the mercury will sink below the cellar. Accordingly the staircase is carried below it, with steps (so to speak) of precisely the same size as those above, and you count as before, 1, 2, 3, &c., as it descends; adding however, to distinguish these degrees from the others, "_below zero_." You may go on in that way as far as 40; but there you must stop. At that point the mercury freezes. He sits down there on his last step, and will not go any further! In the same way if the thermometer is exposed to a heat greater than that of boiling water, the mercury will rise higher than the garret. So the staircase is made to go up higher, and always with steps of the same size, counting from 101 upwards, as far as 350 if you choose; but no further, observe! If the temperature were raised beyond that, the mercury would begin to boil, and then, indeed, good-bye to steps and measured degrees! The gentleman would dance so fast that there would be no possibility of seeing anything, to say nothing of his flying away! Now nothing is easier than to use the thermometer. You place it in the situation where you want to measure the heat, and the mercury goes up or down of itself until it reaches the degree which corresponds with the temperature of the place. It is much more convenient than your mamma's yard measure, which has to be moved about over the stuff, and which is very apt to slip if you do not hold it carefully. Dressmakers would be delighted to have a measure which only wanted laying upon the material, and which would unroll itself and stop short just at the proper point. And this kind of office the thermometer really performs. We will suppose to-day to be the 30th of November. I have just carried the thermometer out of doors; the mercury has fixed itself at the second degree _below zero_. This tells me that it is freezing cold. My fingers have told me so already; but exactly to what extent they could not say. Just now in the room, the mercury was at the 15th degree _above_ zero, thanks to the stove in which we have a good fire. In summer-time it rises to 25, 26, or 28 degrees. I once saw it climb as high as 33 degrees: in the shade of course, you understand; in the sun it would have been quite another affair. Well! there was a universal outcry against the heat. Grown-up young ladies whom I try to teach all sorts of things as I do you, pretended that it was impossible to work. Yet I should find a still greater heat inside my body, if I could get the thermometer there. Have no fears, however; I am not going to make a hole in it: luckily there is one already. I put the ball of mercury into my mouth. And now I can almost tell without looking. The mercury was on its way up the staircase as soon as I took the ball in my hand--and now it has reached the 37th step. You can try the experiment on yourself, but I forewarn you that it ought to be rather hotter with you than with me: the mercury will probably rise a degree higher. I will not promise that in your grandpapa's mouth it may not sink a degree--but that will be all. In different mouths it has, between the 38th and 36th degree, room for the play of a little variation, but it can no more go beyond these than a tethered cow can get beyond the circle made by her cord as she turns round the stake. Go round the world with your thermometer, pop it into everybody's mouth, wiping it if you choose as you proceed, you will always find the mercury on guard. Its tethering cord is somewhat elastic, like everything else about us; but if by any accident it should exceed its limit by even one degree above or below, it would be quite as extraordinary as meeting a giant of eight feet, or a dwarf of three--which one does see occasionally, although the standard of human height varies generally round the centre of five feet. Since there is a fire always kept burning within us, there is no difficulty in comprehending why our bodies always keep warm. Of course, however, the fire must be kept brighter in winter than in summer, but people have no need to be told so. Nature provides for the necessity. She gives us more appetite in cold than in hot weather; not that we can perceive much difference in ourselves in this respect from winter to summer; for our bodies stick to their accustomed habits, and call out pretty loudly for the same daily rations, though without having the same need of them. In order to estimate fairly the connexion which exists between the internal need of food--_i.e.,_ of combustible matter--and the external temperature, we must compare the Hindoo, who lives on a pinch of rice a day, between the tropic and the equator, with the Esquimaux, who, to keep up his 37 degrees of heat, beyond the polar circle, in a country where European travellers have seen mercury freeze, sometimes swallows from ten to fifteen pints of whale-oil at a sitting! Just fancy _whale-oil!_ which is much nastier than even cod-liver oil, if you ever tasted that; but, on the other hand, it is a thorough _combustible_, and the poor people are not so very particular: come what will, the fire must be kept up, and that briskly. But without going thus into extremes, a friend of mine once told me that in Portugal, the land of oranges, it is not uncommon to see gentlemen and ladies (that is to say, those who can eat and drink what they please) dine standing, in five minutes, on a bit of bread and whatever else may be handy. Propose this system to the inhabitants of our colder and damper climate, whose very young ladies, fair and delicate-looking as they are, need a helping of good roast-beef for dinner to keep life in them, and they would only laugh at you. But those who were well instructed could go on to inform you that the chilly atmosphere of northern countries creates the necessity for a more active internal fire than is ever needed under the burning sun of Portugal, and that a mouthful of bread per day will not, in their case, suffice to maintain the appointed thirty-seven degrees of heat. For the same reason, Spaniards drink water, and are satisfied; whereas English wine-merchants add brandy to a good many foreign wines, or they would be quite unacceptable from being deficient in combustible. It is for the same reason, also, that Russians can swallow, without wincing, bumpers of brandy which would kill a Provençal outright: and that the Swedish Government has no end of trouble to keep the country people from converting into brandy the corn that ought to go to the miller; whilst the Mohammedan Arabs accept without difficulty that precept of the Koran which forbids the use of wine and spirituous liquors. It is easy for the Arabs, who are kept warm by their climate, to do without brandy. It is less easy for the Swedes, who are surrounded by cold. All this comes as a matter of course, and we do the same thing ourselves, without being unusually sagacious. In January, when the thermometer goes down to twelve or fifteen degrees below zero, I put more fuel into my stove than I am doing to-day, with only two degrees of cold to bear with. There is nothing surprising in all this. The wonderful thing is, that when an Englishman goes to India, he takes his roast beef and his spirits with him, and in a temperature of more than thirty degrees of heat, quietly heaps up fuel in his stove, just as if he was in England, or nearly so. You think he will set fire to the house, perhaps. But no. Send the thermometer to his mouth for information, and it will only mark down thirty-seven degrees; neither more nor less than in the mouth of a rice-eater! The stove has more sense than its owner. It only burns just what hydrogen and carbon it wants, and takes no more trouble about the remainder than if it had not been eaten. How about the remainder, then? you ask; if it is not consumed for use, what becomes of it? Do you remember, my dear child, that long ago, after explaining the office of the bile and the liver, I put off telling you what the bile _consisted of_, until we had talked about the lungs and respiration? Well, the time has come now; so listen. The hydrogen and carbon which is not consumed by the oxygen in the blood, is seized upon by the liver, who employs it in the manufacture of bile. Therefore the greater the amount of unemployed hydrogen and carbon there is in the blood, the greater is the quantity of bile manufactured by the liver--that is all. When once the body has attained to its proper degree of heat, it is in vain you load it with combustibles; it will not get any warmer, do what you will. Only you will have cut out so much extra work for the liver, and the poor wretch will have to get through it as he can. Accordingly, what happens in the long run to our great eaters and drinkers, whether in India or elsewhere? The bile-manufacturer, overwhelmed with work, gets worn out at last, and kicks; and people come home with that miserable disease, which is called the "liver-complaint." This is one explanation of that wonderful uniformity of temperature which, happily, human imprudence cannot disturb. But the blood has a second resource for getting rid of its superfluity of hydrogen and carbon, and herein especially is displayed the beautiful foresight with which everything about us has been prearranged. We are told that wolves, when they get hold of a larger piece of meat than they care to eat at the moment, carry off what they do not want to some corner and bury it in the ground, whence they get it again when their hunger returns. Dogs sometimes do the same; and the blood has a similar instinct. Listen attentively, for this is very interesting. I light a candle and you see a bright flame, which will last as long as there is any tallow below the wick. Can you tell me what it proceeds from? Nay, do not laugh at the question; it is quite to the purpose, I assure you. We know, do we not, that the substances which burn best are those which are full of hydrogen and carbon? Tallow, then, is one of those substances. But tell me further, if you please, what is tallow? Tallow is _mutton fat_, allow me to say, if you never heard it before. Now comes the question, who provided the sheep's fat with such a quantity of hydrogen and carbon as to qualify it for making candles? The sheep's blood undoubtedly, since blood is the purveyor-general of living bodies--of the sheep's body as well as of our own. But how came it that the sheep's blood had so large a stock of these materials? Undoubtedly, again, because there was more of them in the food the sheep had eaten than the oxygen was able to consume or the liver to employ. In short, the sheep has lungs and a bile-manufactory, as we have; oxygen performs the same office for it as for us. What takes place in its body in the matter of respiration is an exact counterpart of what happens in ours, and the history of its fat is simply the history of our own. Now do you think it is for our sakes that the sheep's blood deposits its fat in little pellet-like morsels throughout the body; do you suppose the poor creature works in this manner merely to have the honor of providing us with candles? It is not likely. I was talking about the wolf just now; but there is no need to look beyond ourselves. In many poor people's cottages there is somewhere an old earthen pot in which the savings of each day are carefully put by, penny by penny, as a last resource in time of need. Should a wicked thief succeed in murdering the owner and laying hold of the treasure, he will squander in a few hours of brilliant revelry the precious hoard so slowly got together as a provision for possible needs. And this is what man does, when he kills the sheep and takes its fat to make candles of! The poor animal's blood knew well that bad times might come, that grass might fail, and the combustible matter conveyed into the body become insufficient to maintain its thirty-nine or forty degrees of heat (which is the sheep's measure, who is rather hotter than we are). So it quietly laid up its surplus stock of combustible so conveniently brought to hand, and destined to be burnt little by little in the depths of the organs, should times of scarcity arise. But here steps in man, the universal thief of Nature, and turns it into a beautiful flame, regardless of cost, and burns in one evening what his victim had been economizing for so long. To burn for burning's sake, however, has always been the fate of tallow, the only difference being in the way it is done. Like the poor man's clumsy pence, which were put by to be spent some day or other, only in another manner. It is worth noting here, that some of the Russian soldiers who were in France in 1815 had a very good idea of restoring candles to their original destiny. As children of the north, driven to get fire wherever they could, they ate all the candle-ends they could lay hold of, preferring to burn the tallow, sheep's fashion, inside rather than out! Fat is, then, the savings' bank of the blood; there it deposits its savings, and there it can always find them again in time of need. Witness the fat pig described by Liebig, the great German chemist, which having been swallowed up by a landslip, was found alive at the end of 160 days. Fat was out of the question there, of course; the animal weighed ten stone less than before. We will take the illustrious professor's word on trust, but were a few days subtracted from the account the case would still be a splendid example of the resource which blood finds in fat when other nourishment fails; for the pig had certainly been breathing during the whole 160 days, and as, in all probability, he moved about much slower than usual, his hydrogen and carbon fire was never extinguished for a single instant; of that I am perfectly certain, and you shall soon know why. It was well for the poor fellow himself that he had put by his provisions in time of plenty. And who suffered? Why, the pig's master, who had looked forward with pleasure to the rashers of bacon he should cut by and by from the stores of combustibles in his larder. For once Master Piggy ate his own bacon himself! You understand now, I hope, by what ingenious management that marvellous stove, called an animal, never burns too much fuel, whatever be the quantity it is supplied with, and how, on the other hand, it has always as much as it wants. I have now to explain how important it is that it _should_ always have enough, and that this is not merely a question of heat and cold, as with dining-room stoves, but one of life and death! Cheer up! I have only one more word to say about Respiration, and when you have heard it you will appreciate still better the lesson of economy which you have learnt from Nature to-day. LETTER XXIII. ACTION OF THE BLOOD UPON THE ORGANS. The first time we talked about the Blood, my dear little pupil, I introduced him to you as the steward of your body, and what a steward to be sure! Always awake, as you may remember, always in motion; his pockets ever full of the materials unceasingly required by the indefatigable builders of that human edifice in which it has pleased God to house your dear little self. If you wish really to understand what follows now, we must carry on the simile a little further. A steward not only provides the workmen with materials, but gives them orders as well, and this is part of the blood's business also. He is not only commissary-general, but _whipper-in_ of the whole household, and besides the care of giving out all the stores, has the charge to see that everything is properly done. The unhappy men who purchase prosperity at the dreadful cost of maintaining slavery, pretend that their slaves would do no work worth looking at, were there not always some one behind them with a whip in his hand. Well, our organs are slaves, and slaves of the worst sort. They would never do anything at all, if the blood were not everlastingly whipping them up in his ceaseless rounds. Let him come to a stand-still for one minute, for a second even, and everything stops short; then we are at once in the castle of the Sleeping Beauty in the wood. But perhaps I cannot do better than to compare our bodily machine to a violin--to hit upon something less dismal than slaves--a violin with blood for its bow. As long as the bow runs over the strings the violin makes music and lives; when the bow stops, it is silent and dies. You have never yet had a fainting fit, my dear child; it rarely happens at your age. But you may possibly have seen somebody faint; or, at any rate, you have heard it talked about. Do you know what takes place in such cases? Now and then, in consequence of some violent emotion, but how or why I cannot tell you, all the blood rushes suddenly back towards the heart, as during an earthquake a river will sometimes flow back towards its source, leaving its bed dry. Thereupon the face turns white, as if to give notice that there is no longer anything red below the skin. The organs, no longer stimulated by the blood, leave off work altogether. The brain goes to sleep, the muscles relax, consciousness ceases, and you behold the poor body, from which the soul seems to have departed, give way on all sides, and fall to the ground like a corpse. This is not exactly death, but it is yet an interruption of life. It would be death if nature did not get the upper hand again, and send back the deserter to his post. I may remark here that it was partly on this account that some of the ancients thought the soul was seated in the blood; not a bad idea for people who were determined to pronounce where the soul was, when it is so easy to say one knows nothing about it. But those who placed it in the breath, and who have bequeathed to us those beautiful expressions--_yielding up the last breath--giving up the ghost_--were not wrong neither. In point of fact the blood is not the soul of the body; in other words, does not keep the body alive, otherwise than by keeping up unceasingly and everywhere that magic fire of which we were talking last time. The French people, in their picturesque language, have found an expression, full of energy, to express the action exercised by the master workman, who knows how to make his people work: "_Il vous met le feu sous le ventre._" [Footnote: Literally, _he puts fire under their bellies;_ but here signifying that he makes it so hot that the organs are compelled to continue in motion.] This is, to the letter, the process employed by the blood to make the organs work. It makes a fire under the belly. Unhappily their work only lasts as long as the fire which causes the heat, and which is so necessary to life that it is almost confounded with it. It is the sacred fire of the Roman Vestals, which must be fed night and day under pain of death should it go out. Now, if to feed the sacred fire of life, it be necessary that the blood should everywhere find hydrogen and carbon _unattached_, that is to say, free and ready to unite themselves to oxygen, it is no less necessary that he should bring oxygen with him everywhere. Else there would be no marriage, and therefore no fire. Oxygen is, then, the talisman which brings the organs to obedience. Without oxygen he would be a slave-driver without his whip; his orders would be despised. If the organs were to be deluged with _venous_ blood--with that black blood which has lost its oxygen, they would not stir any more than if they had received so much water. They acknowledge nothing but _arterial_ blood--red blood--blood rich in oxygen. That is what they respect, and which has authority over them; the other is a bankrupt who has lost his credit with his cash; those whom he fed but lately now laugh in his face. And as our good steward spends all his oxygen every time he goes his rounds, it would soon be over with him, and, consequently, with us, too, if he had not some method of replenishing his purse after each journey. Happily the lungs are the inexhaustible chest to which he always returns to renew his right of authority; that is, his power of preserving life. When it comes to the _last sigh_, the last effort of the diaphragm by which the chest is closed forever, we must bid adieu to life. In yielding up that, we have in very truth yielded up the ghost. This is no joke, as you see, and it would not do to be caught unprepared, with an inexorable necessity hanging over one, which never allows a moment's respite. The blood acts like a reasonable being, therefore, in laying up his stores of combustible in reserve. Moreover, whether he has done so or not, the fire must go on all the same; that is absolutely necessary; and if he has no spare fat to feed it with, when, from any cause, the stomach leaves off working, he makes use of anything he can lay his hands upon. I know a story on this subject which will amuse you. There lived, in the reign of Francis I. of France, an honest countryman, of Périgord, named Bernard Palissy. At that time everybody could not afford to have earthenware plates, as they have now. It was a manufacture of which only the Italians had the secret, and Bernard, who knew something of the matter, from being a glass-worker, took it into his head to try and find it out entirely by himself. So, without asking anybody's advice, he turned potter, built ovens, picked up wood as he could, manufactured his first pots, whether well or ill, made a beginning, and waited. He had fifteen or sixteen years of it before he succeeded; fifteen or sixteen years of ruinous experiments, which would have discouraged a less sturdy heart than his. But he, after he had succeeded in picking up some money by his church windows, returned to his work with unconquerable perseverance, insensible to poverty, deaf to the ridicule of neighbors, and unmoved by the abuse of his wife, who was furious, as you may suppose, at being forced to play the heroine without having the least turn for it. And one fine day there was a grand uproar in La Chapelle-Biron (that was the name of his village). "Bernard Palissy has gone mad," said everybody; "he is burning up his house to bake his pots." And upon my word it was true! Wood happened to be wanting while a batch was in the oven, and Bernard having begun by using up the garden palisades, took next the large tables, and at last the floor of the house! What his wife had to say, I leave you to judge; as for him he listened to nothing; but, fixing his eyes on the insatiable furnace, threw in one thing after another, caring only for the risk to his handiwork. The ceiling would have followed the floor had not his pots been sufficiently baked without. And thus, and thus, does the blood, when combustible matter fails him! He demolishes the house, and throws it, bit by bit, into the fire. The fat goes into it naturally enough, as I have already explained to you. It is the fuel-store of the house. It was put by on purpose, and may be used up without injury. Then comes the turn of the muscles; more useful without being indispensable. Those are Bernard Palissy's palisades one may contrive to do without them. They melt away, so to speak, after a few days' fast, and you find yourself what people call "nothing but skin and bone." But then, if this condition is prolonged, and the exhausted flesh cannot supply the demand, the blood does not hesitate a moment. He boldly falls upon the most important organs, without stopping to consider; he, too, is devoted solely to his work, and that, like the baking of pots, never comes to an end by being completed; if external help does not arrive in time, the house soon becomes uninhabitable, and life slips away. The man dies of hunger. But in the same way that poor Bernard Palissy was in reality working, all the time, for his wife and children, whose future well-being he strove for as the final end of all his efforts, though at the risk of letting them sleep under the bare heavens; so the blood was laboring up to the last moment for that very life which he at last turned out of doors; and the work of destruction which caused its final departure has had in reality the effect of prolonging its stay. Without it, all would have been over long before. LETTER XXIV. THE WORK OP THE ORGANS. Thus much is settled, then. It is the blood which sets everything in motion throughout the body. The organs are idlers who would do nothing but for him; they only work when goaded on, if I may use the expression, by that fire--always on the point of going out--which he is perpetually coming back to rekindle, thanks to the oxygen he carries with him from the lungs. This will enable me to explain many things, which, although not new to you, you have probably never tried to account for before. To begin with: do you remember what happened to you the other day, when you tried to overtake your mischievous brother in running, and he, taking advantage of his school-boy legs, led you mercilessly through all the garden walks, without having the grace even to let you catch him at the end? You were quite out of breath; your heart beat so rapidly it almost hurt you; and you were so hot that the perspiration poured in great drops down your face, so that your mamma, quite frightened, took you up in her arms and carried you to the fire; for the coolness of evening was coming on, and a little girl drenched with perspiration is soon chilled. Tell me now, what connection was there between your overrunning yourself in a race and the extraordinary degree of heat which came over you so soon? Your cheeks were cool and fresh when you began to run; what made them so red all at once, and especially at a moment when the air was cool and fresh in the garden? You open your eyes in surprise; you had never thought of this. No! that is just the way with little girls. They run; they get hot; it seems as natural as warming oneself in the sun, and they never ask why it is so. Yet you could almost tell me the "why" yourself, if you stopped to think about it, now that you are what your school-boy brother would say "_up to a thing or two;_" but to save time, I will help you. You run as a bird flies, without thinking about it. Nevertheless, if you could see with a magic glass all that takes place in your body while those active little feet are carrying it like a feather across the garden, you would be perfectly amazed. One of these days, when we have finished our present history, I will tell you that other one, which is equally worth the trouble. It is enough for the present to know, that a very complicated piece of work is being carried on there, in which almost all the muscles of the body take part at the same time, contracting and relaxing in turn, like so many springs, of which each either drives forward or holds back a part of the machine. In fact, while your eyes and thoughts are fixed on the butterfly which is flitting away from you through the air, there is going on within you such an unheard-of outlay of efforts as could never be got out of our idlers if the terrible steward did not lash them severely. Now, his lash, as we have said often enough, is that eternal fire, the materials of which he conveys to all parts of the body. On those special occasions, therefore, he is obliged to make his fire burn much more briskly than usual--exactly like railway engine-drivers, who increase the heat of their fire to get up steam in proportion to the speed they wish to go. From this you will understand that it is no great wonder that your small frame should get heated from such work as racing and chasing; and that if you pursue it too long, the perspiration which comes out all over you is sufficiently explained. This is not all, however. The fire, whose strength has to be increased, naturally requires a larger amount of combustible matter than before, and forasmuch as there is only a certain fixed quantity in each drop of blood, whenever the muscles want more than usual, the blood itself must flow to them in greater abundance. Now if it were a question of supplying only one part of the body (as it is, you may remember, of supplying the stomach during the progress of digestion), he might contrive to accomplish his task there by neglecting it elsewhere, and overflow one organ at his ease, at the expense of all the rest. But in this case he is wanted everywhere in the same abundance. It is not a question of taking one muscle's share for the benefit of another. From one end of the body to the other, all want to be deluged at once. And remember that these exigencies do not bring a drop more blood into the body. How is he to get out of his difficulty then, this overwhelmed steward of ours? Well! just as your mamma manages, my dear, when there is more to do than usual in the house;--by running quicker than ever from the cellar to the garret, and from your room to your papa's! That is called doubling oneself; and this gallant blood doubles itself to some purpose. He runs and runs and runs, arrives in hurried streams, and returns full gallop, passing and repassing through the heart, which empties and fills itself in sudden jerks. Unluckily, the poor heart is a delicate sort of person, who does not like having his habits disarranged, and this forced work soon makes him desperate. The other day, in his despair, he knocked with all his strength against the walls of his little chamber, to warn his young mistress that he could bear no more, and that they were both of them in danger. In fact, you ought to know that if one was infatuated enough to go on running too long, one might die of it. When you learn ancient history, you will probably be told of what happened to the soldier of Marathon, who flew like an arrow from the field of battle to the gates of Athens, that he might tell his fellow-citizens a quarter of an hour earlier, that his country was saved; and he fell dead on his arrival. But it is not the heart only which suffers by this mad career of the blood. During each journey it performs it passes through the lungs, which in their turn are forced to play with hasty jerks. And this is well for our good steward; for the lungs, filling with air at each descent of the diaphragm (if you remember what we have said before), more air, and consequently more oxygen, comes in, and the blood has by this means a larger stock on hand, ready to help him out in the unusual waste which is just then going on in the muscles. I spoke just now of railway steam-engines. See how self-supporting ours is! The greater the amount of fire wanted, the faster the blood flows; and the faster the blood flows, the oftener does the coffer re-fill itself, whence comes the supply of oxygen requisite for keeping up the fire. All this goes on at once, by one impulse, and the balance between the receipts and expenditure settles itself of its own accord. How thankful many families would be if their money-chest would but fill itself in the same way--in exact proportion as they spend the cash! There is only one slight drawback, which is, that the diaphragm gets tired with the unaccustomed gallop it is thus forced into. It falls into convulsions, therefore, like its neighbor the heart, and the breathing is stopped, from having been driven too rapidly. An excellent example for people who want to spend too much at once; showing that Nature herself cries out against it, even when the only thing wanted is atmospheric air. Now, run if you dare! And, to tell you the truth, it would be a great pity if you did _not_ dare; for our good God has made little children for running. They have nimbler blood than we older grandfathers, more elastic lungs, and consequently more oxygen to spend at a time. But you must confess that it is a great pity we should run all our lives as many people do, without having the slightest idea of these admirable contrivances, thanks to which we are enabled to do it. We can run all the same, it is true, without the knowledge, the little child as easily as the little roebuck, which sets a similar machine in motion. But it is no use talking about the little roebuck; it cannot learn what God has done for it, but the little child can, if he will. Furthermore, there is nothing to be really alarmed about, for those great commotions only occur when we have committed excess; and it is a very good thing, in a general way, for the blood to give us a stroke of his lash from time to time. I told you lately that the fire which sets the organs to work is life; and it is no misfortune to be a little more alive than usual. Besides which, this increased activity of the internal fire does not serve us in running only. Every time that a man makes an effort; every time he lifts a weight, or handles a tool, the blood rushes forward to deluge the muscles that are thus called into play; the heart beats more quickly, and the air streams in greater abundance into the lungs. Look at a man chopping wood. If the log resists too much, if for a minute or two the man has to strike blow after blow without stopping, you will soon see him panting for breath, just as if he had been running a race. On the other hand, he will have gained something from chopping his log besides the right of warming himself before it at the fire. Blood does not carry fire only into the muscles; he supplies them with nourishment also, does he not? Every drop of blood deposits its little offering as it goes by, and consequently the greater the number that pass along, the richer is the harvest for the muscle. Look, accordingly, at the laboring classes. How much healthier and stronger they are than those who do not work! I speak, of course, of working with one's limbs generally; for those poor girls who work from morning to night, sitting on their chairs, are none the better for it, but, on the contrary, worse. There are also certain worthy fellows who, like myself at the present moment, drive a pen over sheets of paper for half a day at a time, whose muscles never get any bigger for it, that is quite clear. Moreover, one condition has to be fulfilled, which unhappily is not always done. The more people labor, the more they ought to eat. To you, who have just been looking at the drama that is performed in the body every time a muscle is set in motion, this is obvious enough. There is no fire without smoke, says the proverb. It would have been much better to have said,--there is no fire without fuel;--and the fuel for our fire is, as you know, what we eat. Try if you can get one stove to burn more brightly than another, if you have put less fuel into it. Yet, alas! this is what many poor wretches are obliged to do but too often; and then the blood, instead of feeding their muscles, consumes them, for the reasons I gave, in telling you the story of Bernard Palissy. Think of this, oh my dear child, when you are grown up, and never grudge those who work for you their proper share of food. Here I see many other lessons crowding up, out of what you have just learnt. And first Nature herself, taken as you find her, shows you that manual labor is, for us, a most beneficial condition of existence; that it brings about a re-doubling, an exaltation of life; and that consequently, we have no need to look down upon those who gain their bread, as we word it, by the sweat of their brows. I told you this before, in speaking of the hand, which is of so much more use to those people than to you; and I repeat it now for another reason, viz.: because labor elevates him who undertakes it, and creates a real physical nobility. Barbarians in old times, who knew nothing noble nor grand but war, despised labor, and left it to their slaves; so much so, that the name _servile labor_, _i.e._ the labor of slaves, has stuck to it in some places. As for war, the lot of the ancient nobility, I scarcely dare to say much against it, however much I should like to do so on some accounts. For, after all, so long as there are ruffians to trample on the weak, one is only too glad to find brave men ready to risk their lives in keeping such rascals down: so long as there are wolves, we must needs keep shepherds' dogs. But in spite of everything, the best that can be said in favor of war is, that it remains a sad but inevitable necessity, and that to get rid of it, more is wanting than the wish. What a contrast to labor--that contest of Man with Nature;--that merciful and fruitful war, where victories are not estimated like other victories, by the number of the slain, but which, on the contrary, scatters fresh life around it as it spreads; fresh life in the laborer himself, by the very act of work, fresh life around him without, by the fruits that work produces! Between the man who dies in slaying others, and the man who keeps others alive by living longer himself, it seems cruel to make invidious comparisons; but if it be just to honor the first out of respect for the cause he has defended, whenever that cause is respectable--it is, to say the least of it, not less just to do equal honor to the second. But let us come down from these philosophic heights, and return to you, dear child; to you, who have nothing to do with war, its massacres or its laurels. It is true, however, that you have nothing to do either, with chopping wood, and I am not asking you to undertake any such thing. But in the life of a woman, from the time of her childhood upwards, a thousand things arise for the hands to do, and the question is, how often you are likely to feel ashamed of not sending for the servants to do them? Avoid this false and fatal idea as much as possible. The work of the hands dishonors no one; it is honorable. To cast it aside altogether is to make yourself smaller instead of greater; to deprive yourself of one of the glories and the joys of life. If a good thing is set before you at dinner, do you send for the servants to eat it? If an occasion arises for making the blood circulate more rapidly in your veins, and of increasing the strength and life with, in you into the bargain, why make _them_ a present of it? Especially when it cannot be an agreeable present considering that good servants have plenty of such opportunities from morning to night every day. There was once upon a time a Persian prince staying in Paris, who was taken to a very fashionable ball, that he might see a specimen of European civilization. I am not talking about a prince in the "Arabian Nights;" mine lived, I believe, in the time of Louis Philippe. The beautiful dancers wheeled round, their eyes brilliant with pleasure, in the arms of elegant cavaliers; one would have said that the whole of this airy troop, swaying to and fro in time to the lively flourishes of the music, was animated by one soul; everything seemed full of joy in that large and splendidly lit hall, and mothers secretly envied their daughters as they passed and re-passed before them. Our oriental alone scanned with a disdainful eye this youthful enjoyment. When it was ended,--"How is this?" said he to his conductor; "did you not tell me that I was to see here the most distinguished families of Paris?" "Certainly," replied the other; "among those young ladies who were just now dancing before you, there were at least twenty of the grandest heiresses of France." "Young ladies who dance! Come, come! In my country we have dancers, but they are paid for it. Our wives are never permitted to dance themselves. That is all very well for the common people!" Remember, when needful, the contempt of this Persian prince, my dear child; and let me beg of you, work for yourself. The dance of labor is worth quite as much as that of the ball-room, when you give your heart to it. It is even worth more, very often; and next time I will tell you why. LETTER XXV. CARBONIC ACID. We are going to make acquaintance to-day with a new personage, who well deserves our attention. It is the child of oxygen and carbon, [Footnote: This is the name learned men have given to Charcoal.] though not in the same way that you are the child of your parents. To tell you how it is made is more than I am able. It is a _gas_, or if you like the word better, it is an _air_; for when we say "gas," we mean "air;" only it is always a different sort of air from the air of the atmosphere, which learned people are not in the habit of calling _gas_. I cannot, therefore, show you _carbonic acid_ itself, for it cannot be seen any more than the air which fills an empty glass. But I can tell you where there is some, and you even probably know it by its effects, although you have never heard its name. Do you remember, on your aunt's wedding-day, that there was a sparkling wine called champagne, at the grand breakfast? You smile, so I conclude somebody gave you a little to taste; and if so, you will remember how sharp it felt to your tongue. Do you remember, too, how the cork flew out when they were opening the bottle, and how the noise of the "pop!" startled more little girls than one? It was _carbonic acid_ which sent the cork flying in that wild way; the carbonic acid which was imprisoned in the bottle, in desperately close quarters with the wine, and which accordingly flew out, like a regular goblin, the moment the iron wire which held down the cork was removed. What sparkled in the glass, making that pretty white froth which phizzed so gently, as if inviting you to drink, was the carbonic acid in the wine, making its escape in thousands of tiny bubbles. What felt so sharp to your tongue was the same carbonic acid, in its quality of acidity, for thence it has its name; the word _acid_ being borrowed from a Latin word signifying the sharp pungent taste, almost _fine-pointed_ as it were, peculiar to all substances which we call _acids_. It is carbonic acid also which causes the froth in beer and in new wine when bottled. It is he who makes soda-water sparkle and sting the tongue, and ginger-beer the same, if you happen to like it; and so far you have no particular reason for thinking ill of him. But beware. It is with him as with a good many others who have sparkling spirits, who make conversation effervesce with gayety, and who are very seductive in society when you have nothing else to do but to laugh over your glass, but whose society is fatal to the soul which delivers itself up to them. This charming carbonic acid is a mortal poison to any one who allows it to get into his lungs. You remember what a violent headache your servant suffered from the other day after ironing all those clothes you had in the wash? She owed that headache entirely to this work which she did for you. She had remained too long standing over the coals over which her flat-irons were being heated. You know already that when charcoal burns, it is from the carbon uniting with the oxygen of the air; from this union proceeds that mischievous child, carbonic acid gas, in torrents, and the poor girl was ill, because she had breathed more of this than was good for her health. Observe well, that the room-door was open to let in the fresh air, and that there was a chimney, to allow the carbonic acid to escape. It was on this account that she got off with only a headache. Unhappily, there have sometimes been miserable people who, weary of life, and knowing this, but not knowing or thinking about the God who overrules every sorrow for good, have shut themselves up in a room with a brazier of burning charcoal, after taking the fatal precaution of stopping up every opening by which air could possibly get in; and when at last, in such a case, uneasy friends have forced open the well-closed door, they have found nothing within but a corpse. Then, too, there are those frightful accidents of which we hear so often, of workmen groping their way down into long disused wells, who have died as they reached the bottom; or of sudden deaths in coal-pits. In general these have been owing to the poor victims encountering the long pent-up carbonic acid gas, whose poisonous breath blasted and destroyed them at once. You may well ask why I am telling you such horrible stories, and what I am coming to with my carbonic acid? But you have more to do with it than you think, dear child. You, and I, and everybody we meet, nay, and the very animals themselves, since their machines are of the same sort as ours, are all little manufactories of carbonic acid. The thing is quite clear. Since there is a charcoal fire lit in every part of our body, there always arises from the union of the oxygen brought by the blood with the carbon it meets in our organs, that mischievous child we have been talking about; and our throat is the chimney by which he gets away. He would kill us outright were he to stop in the house. This is how it comes about: In proportion as the blood loses its oxygen, it picks up in exchange the carbonic acid produced by combustion, so that it is quite loaded with it by the time it returns to the lungs. There it takes in a fresh supply of oxygen, and discharges at the same time its overplus of carbonic acid, which is driven out of the body by the contractions of the chest, pell-mell with the air which has just been made use of in breathing. You are aware that this air is not the same at its exit as at its entrance to the body, and that if you try and breathe it over again it will no longer be of the same use to you. That is because it has lost part of its oxygen and brings back to you the carbonic acid which it had just carried off. If you take it in a third time, it will be still worse for you; and in case you should continue to persist--the oxygen always diminishing, and the carbonic acid always increasing in quantity--the air which was at first the means of your life will at last become the cause of your death. Try, as an experiment, to shut yourself up in a small trunk, where no fresh air can get in; or even in a narrow closely-shut closet, and you will soon tell me strange news. There will be no occasion to light a charcoal fire for you in there. Enough is kept burning in your own little stove, and you will poison yourself. You see now that the dreadful stories I was telling a short time ago have something to do with you, and that it is a good thing to be warned beforehand. And now tell me, when a hundred people--or I ought to say, a hundred manufactories of carbonic acid--are crowded together for a whole evening, sometimes for a whole night, in a space just big enough to allow them to go in and come out; tell me, I say, if that is a sort of thing which can be beneficial to the health of little girls whose blood flows so fast, and who require so much oxygen; and whether, on the contrary, it is not one's duty to keep them away from such scenes? There may be amusement there, I know; but the best pleasures are those for which one does not pay too dearly. I have seen the very wax lights faint and turn pale all at once, in the very midst of those murderous assemblies, as if to warn the imprudent guests that there was only just time to open the windows. And this reminds me of a point I had nearly forgotten. Wax-candles arc like ourselves. In order to burn, they must have oxygen, and, like us, they are extinguished by carbonic acid. But like us also--and indeed to a greater extent, because they consume much more charcoal at once--they manufacture carbonic acid. Hence that very illumination which affords the company so much pleasure and pride is plainly an additional cause of danger. Each of those wax-lights which is spread around with such a prodigal hand, the only fear being that there may not be enough of them, is a hungry intruder employed in devouring with all his might the scanty amount of oxygen provided for the consumption of the guests. From each of those cheerful flames--the suns, as it were, of the festive assembly--shoots out a strong jet of carbonic acid, contributing by so much to swell out the already formidable streams of poisoned gas, exhaled to the utmost extent by the dancers. And wait--there is still something else I was forgetting. You dance. And I told you last time at what cost you have to dance. You have to make the fire burn much quicker than usual, that is, to consume a great deal more oxygen at once, and so you double and treble the activity of the carbonic acid manufacture: and this just at the moment when it would be so convenient that it should go on as slowly as possible! After this, you need not be surprised that people should look fagged and exhausted next morning. What astonishes me is that they are not obliged to lie in bed altogether, after treating their poor lungs to such an entertainment. And even if you have spared your legs, you are not much better off, as you are sure to find out in time, especially if the thing is repeated too often. When I told you just now that the dance of labor was worth as much as the dance of the ball-room, was I right or wrong? What do you say yourself? I could repeat the same of theatres--places of entertainment specially adapted for impoverishing the blood, and ruining the health of the happy mortals who go there, evening after evening, to purchase at the door the right of filling their lungs with carbonic acid, not to speak of other poisons. You must see clearly that such places as those are not fit for little lungs as dainty as yours; and this may help you to submit with a good grace when you see people going there without you. Grown-up people escape moreover, because the human machine possesses a strange elasticity, which enables it to accommodate itself--one scarcely knows how--to the sometimes very critical positions in which its lords and masters place it without a thought. But to do this, it is well that it should be thoroughly formed and established; for you run a risk of injuring it for ever, if you misuse it too early in life. Tell this to your dear schoolboy brother, when he wants to smoke his cigar like a man. If his lungs could speak, they would call out to him that it was very hard upon them, at their age, to be so treated, and that he ought at any rate to wait till they had passed their examinations! But I must not get into a dispute with so important an individual, by throwing stones into a garden which is not under my care. For you, my dear child, the moral of this day's lesson--which to my mind is much more alarming than a hobgoblin tale, since it concerns the realities of every-day life--is clear; and it is this: Seek your amusements as far as possible in the fresh air. In the summer, when the lamp is lit, bid your mamma a sweet good-night, and go to bed. In the winter do not wait till there is a great quantity of carbonic acid in the room where the grown-up people are sitting, before you retire to your own like a reasonable girl, anxious not to do mischief to that valuable and indefatigable servant, the poor blood! Not to mention that if she were to injure him too much, she would have to bear his grumbling for the rest of her life. We cannot change him as we change other servants. LETTER XXVI. ALIMENTS OF COMBUSTION. We have spent a very long time, my dear child, over the little fire, which goes on burning secretly in every one of us, quietly devouring what little girls eat with such a good appetite, quite unsuspicious of what they are doing it for. However, if I mean to finish the history of our mouthful of bread, I must push on to its last chapter. The _whole_ of what we eat is not burnt, as you may easily suppose; for, if it were, what would the blood have left to feed the body with, and to repair in due proportion the continual destruction or waste which goes on in our organs? Our food, or "_aliments_" as the general collection of different sorts of food is called, are divided into two very distinct sets: some, which are destined to be burnt, and which are called _aliments of combustion_; others, which are destined to nourish the body, and which are called _aliments of nutrition_. I have to tell you now about these last, and you will find their history by no means uninteresting. Learned men having detected, beyond the possibility of a doubt, the existence of these two sorts of aliments, one is tempted to think they ought to have made it known to the cooks, and that ever since so important a discovery, the dishes on all well-regulated tables should have been arranged accordingly; aliments of combustion on one side, aliments of nutrition on the other. It cannot be enough merely to give your guests a treat; you ought to provide them with everything necessary for the proper fulfilment of the claims within; and if you give some nothing but combustibles, leaving the others no share of fuel, how will they be able to manage? Nobody thinks about this, however; not even cooks, to begin with, who, as far as fire is concerned, find they have had quite enough to do with it in their cooking; and as for the guests, when they have had their dinner they go away satisfied, as a matter of course, quite as well provided for as if the mistress of the house had made her calculations, pen in hand, while writing out the bill of fare, with a view to combustion and nutrition. Now, how is that? It is because the two sorts of aliments are, for the most part, met with together in everything we eat, so that we swallow them at once in one mouthful; and have therefore no need to trouble ourselves further on the subject. There is our bit of bread, for instance. What is bread made of? Of flour. Bread, then, must contain all that was previously in the flour. Very good. Now I will teach you how to discover in flour the aliment of combustion on the one hand, and the aliment of nutrition on the other. Take a handful of flour, and hold it under a small stream of water; knead it lightly between your fingers. The water will be quite white as it leaves it, carrying away with it a fine powder, which you could easily collect if you were to let the water run into a vase, where the powder would soon settle to the bottom. That powder is starch--the same starch as washerwomen use for starching linen, and which our grandfathers employed in powdering their wigs. You had some put on your own hair one day when you were dressed up as a court-lady of olden time. Now, starch is an excellent combustible. People have succeeded, by means which I will not offer to detail here, in ascertaining almost exactly what it is made of, and they have found in it three of our old acquaintances, oxygen, hydrogen, and carbon, combined together in such proportions that 100 ounces of starch contain as follows: Ounces. Carbon 45 Hydrogen 6 Oxygen 49 --- 100 I give you the calculation in round numbers, so as not to burden your memory with fractions; and I will do the same with the other sums I shall have to go through to-day, this being, let me tell you, an arithmetical day. Besides, I could scarcely take upon myself to warrant the absolute correctness of those very precise fractions people sometimes go into. Even our learned friends squabble now and then as to which is right or wrong over the 100th part of a grain, more or less, in making out their balance, and you and I will not offer to decide between them. I always think we have accomplished wonders in getting even _near_ the mark, and with their permission we will stop there. Starch, then, of whose weight carbon constitutes nearly one-half, is of course a first-rate combustible. Indeed, one may almost consider it the parent, as it were, of at least half our aliments of combustion, for if (in consequence of a certain operation, which nature has the power of performing for herself, in certain circumstances) it loses a portion of its carbon, so that there remain but 36 ounces of it in the 100 of starch, our starch is turned into something else; now can you guess what that something is? Neither more nor less than _sugar_! Witness the grand manufactories at Colmar, in France, where bags of starch are converted into casks of syrup by a process of nature alone; so that the inhabitants of the neighborhood sweeten their coffee at breakfast with what might have been made into rolls, had it been left alone. And this is not all. Give back this starch-sugar into the hands of Nature once more by putting it into certain other conditions, and a new process begins in it. About a third of its carbon will unite itself, of its own accord, with the two-thirds of its oxygen, so as to make carbonic acid, (you are acquainted with that gentleman now) which shall fly off and away, and there will remain--what do you think?--_Alcohol_, that other combustible we talked about, and which burns even better than sugar and starch, since in a hundred ounces it contains as follows:-- Ounces. Carbon 53 Hydrogen 13 Oxygen 34 --- 100 All this astonishes you. What would you say then if I were to tell you that your pocket-handkerchief is composed of entirely the same materials as starch, and in the same proportions too, and that if a chemist were to take a fancy, by way of a joke, to make you a tumbler of sugar and water, or a small glass of brandy out of it, he could do so if he chose. Wonders are found, you see, in other places besides fairy tales; and since I have begun this subject I will go on to the end. Know then that from the log on the fire, to the back of your chair, everything made of wood, is in pretty nearly the same predicament as your pocket-handkerchief; and if people are not in the habit of making casks of syrup and kegs of brandy out of the trees they cut down in the woods, it is only, I assure you, because such sugar and brandy would cost more to make than other sorts, and would not be so good in the end. Should some one ever invent and bring to perfection an economical process for doing it thoroughly well, sugar-makers and spirit-distillers will have to be on their guard! But we are wandering from our subject. If I have allowed myself to make this digression, however, it is because I am not sorry to accustom your mind early to the idea of those wonderful transformations which nature accomplishes, and of which I could give you many other instances. To return to our flour. As soon as all the starch is gone out of it, there remains in your hand a whitish, elastic substance, which is also sticky or _glutinous_, so that it makes a very good glue if you choose; and hence its name of _gluten_, which is the Latin word for glue. When dried, this _gluten_ becomes brittle and semi-transparent. It keeps for an unlimited time in _alcohol_, putrefies very soon in water exposed to the air, and is easily dissolved in a wash of soda or potash. Finally 100 ounces of it contain as follows:-- Ounces. Carbon 63 Hydrogen 7 Oxygen 13 Nitrogen 17 --- 100 Observe the last material named. It is a new arrival, of which I shall soon have something to say. But where am I leading you? you will ask, with all these uninteresting details about glue. Wait a little and you shall hear. You have probably never seen any one bled, which is a pity, as it happens; for if you had, you might have noticed (provided you had had the courage to look into the basin), that after a few seconds, the blood which had been taken away separated itself of its own accord into two portions; the one a yellowish transparent liquid, the other an opaque red mass floating on the top, and which is called the _coagulum_ of the blood or _clot_. This _coagulum_ owes its color to an infinity of minute red bodies of which we will speak more fully by and by, and which are retained as if in a net, in the meshes of a peculiar substance to which I am now going to call your attention. That substance is whitish, elastic and sticky; and when dried becomes brittle and semi-transparent. It keeps for an unlimited time in alcohol, putrefies very soon in water exposed to the air, and is easily dissolved in a wash of soda or potash. Finally 100 ounces of it contain as follows:-- Ounces. Carbon 63 Hydrogen 7 Oxygen 13 Nitrogen 17 --- 100 This substance is called _fibrine_. It goes to form the fibres of those muscles which are contained in a half formed state in the blood. You are laughing by this time I know, and I also know the reason why. I have told you the same story twice over. You have not forgotten my wearisome description of _gluten_, and here I am, saying exactly the same thing of _fibrine_! You conclude I am dreaming, and have made a mistake! But no, I am wide awake, I assure you, and mean what I say. And if these details are the same in the two cases, it is for the simple reason that the two bodies are one and the same thing; _gluten_ and _fibrine_ being in reality but one substance, so that were the most skilful professor to see the two together dried, he would be puzzled to say which came from the flour, and which from the blood. I mentioned that our muscles existed in a half-formed state in the blood. Here is something further. The _fibres_ of muscles exist previously in full perfection, in the bread we eat; and when you make little round pills of the crumbs at your side, it is composed of fibres stolen from your muscles which enable the particles to stick together; and I say _stolen from your muscles_, because they are the _gluten_ which you ought to have eaten. I hope the thought of this may cure you of a foolish habit, which is sometimes far from agreeable to those who sit by you. This, then, is the first great _aliment of nutrition_, and you may make yourself perfectly easy about the fate of those who eat bread. If little girls should now and then have to lunch on dry bread, I do not see that they are much to be pitied. There is the starch to keep up their fire, and the gluten for their nourishment, and that is all they require. The porter above is the only one who finds fault. And in these days porters have become more difficult to please than the masters themselves. Then as to babies who drink nothing but milk, you perhaps wish to know where they get their share of fibrine. And I am obliged to own there is none in the milk itself; but, I daresay, you know curdled milk or _rennet_? The same separation into two portions has taken place there which occurs in the blood when drawn from the arm; underneath is a yellowish transparent liquid,--that is the _whey_; above a white curd of which cheese is made, and which contains a great part of what would have made butter. By carefully clearing the curd from all its buttery particles you obtain a kind of white powder which is the essential principle of cheese, and to which the pretty name of _casein_ is given because _caseus_ is the Latin for cheese. I shall not trouble you now with details about _casein_; but there is one thing you ought to know. A hundred ounces of _casein_ contain as follows:-- Ounces. Carbon 63 Hydrogen 7 Oxygen 13 Nitrogen 17 --- 100 Exactly like gluten and fibrine! Now, then, you can understand that no particular credit is due to the blood for manufacturing muscles out of the cheese of the milk which a little baby sucks. He has much less trouble than the manufacturers at Colmar have in turning their starch into sugar; because in his case the new substance is not only composed of the same materials as the old one, but contains them in exactly the same proportion also. We have a second aliment of nutrition, you see, and I must warn you that it is not found in milk only. It exists in large quantities in peas, beans, lentils, and kidney-beans, which are actually full of cheese, however strange this may seem to you. It would not surprise you so much, however, if you had been in China and had tasted those delicious little cheeses which are sold in the streets of Canton. They cannot be distinguished from our own. Only the Chinese (from whom we shall learn a great many things when we have beaten them so that they will conclude to be friends with us)--the Chinese, I say, do without milk altogether. They stew down peas into a thin pulp. They curdle this pulp just as we do milk, and in the same way they squeeze the curd well, salt it, and put it into moulds--just as we do--and out comes a cheese at last--a real cheese, composed of real _casein_! Put it into the hands of a chemist, and ask him the component parts of a hundred grains of it, and he will tell you as follows:-- Ounces. Carbon 63 Hydrogen 7, etc. I stop there; for you surely know the list by this time! Only the third aliment of nutrition remains to be considered, for there are but three; and I will tell you in confidence, what is stranger still, viz., that there is in reality but one! But we have had enough food for one day, and I do not wish to spoil your appetite. We will reserve the rest for another meal. LETTER XXVII. ALIMENTS OF NUTRITION (_continued_). NITROGEN OR AZOTE. There is a favorite conjuring trick, which always amuses people, though it deceives no one. The conjuror shows you an egg, holds it up to the light that you may see it is quite fresh, then breaks it; and--crack--out comes a poor little wet bird, who flies away as well as he can. This trick is repeated in earnest by nature every day, under our very eyes, without our paying any attention to it. She brings a chicken out of the egg, which we place under the hen for twenty-two days, instead of eating it in the shell as we might have done, and we view it as a matter of course. Yet we do not say here that the bird may not have come down the conjuror's sleeve, or the hen may not have brought it from under her wing. It was really in the egg, and its own beak tapped against the shell from within and cracked it. How has this come about? No one can have put that beak, those feathers, those feet, the whole little body, in short, into the egg while the hen was sitting upon it, that is certain. It is equally certain, then, that the liquid inside the egg must have contained materials for all those things beforehand; and if Nature could manufacture the bones, muscles, eyes, etc., of the chicken, out of that liquid while in the egg, she would probably have found no more difficulty in manufacturing your bones, muscles, eyes, etc., from it had you swallowed the egg yourself. Here, then, is an undeniable _aliment of nutrition_. It is called _albumen_, which is the Latin word for _white of egg_. It is easily recognized by a very obvious characteristic. When exposed to a temperature varying from sixty to seventy-five degrees of heat, according to the quantity of water with which it is mixed, _albumen_ hardens, and changes from a colorless transparent liquid, into that opaque white substance, which everybody who has eaten "hard-boiled eggs" is perfectly well acquainted with. I will only add one trifling detail. 100 ounces of albumen contain as follows: Ounces. Carbon 63 Hydrogen -- You can fill up this number yourself, can you not? And knowing the 7 of hydrogen, you may guess what follows! After what we have talked of last time, here is already an explanation of the chicken's growth. But let us go on. You recollect that yellowish liquid I spoke about, which lies underneath the _clot_, or _coagulum_ of the blood? I will tell you its name, that we may get on more easily afterward. It is called the _serum_, a Latin word, which, for once, people have not taken the trouble of translating, and which also means _whey_. Put this _serum_ on the fire, and in scarcely longer time than it takes to boil an egg hard, it will be full of an opaque white substance, which is the very _albumen_ we are speaking of. Our blood, then, contains _white of egg_; it contains in fact--if you care to know it--sixty-five times more white of egg than fibrine, for in 1,000 ounces of blood, you will find 195 of _albumen_, and only three of _fibrine_; of _casein_, none. Nevertheless we eat cheese from time to time. And we generally eat more meat than eggs, and meat is principally composed of fibrine! I should be a good deal puzzled to make you understand this, if we had not our grand list to refer to. Ounces. Carbon 63 Hydrogen 7, etc. _Fibrine_, casein_, _albumen_, they are all the same thing in the main. It is one substance assuming different appearances, according to the occasion; like actors who play several parts in a piece, and go behind the scenes from time to time to change their dresses. The usual appearance of the aliment of nutrition in the blood is _albumen_; and in the stomach, which is the dressing-room of our actors, _fibrine_ and _casein_ disguise themselves ingeniously as _albumen_; trusting to _albumen_ to come forward afterwards as _fibrine_ or _casein_, when there is either a muscle to be formed, or milk to be produced. Know, moreover, that _albumen_ very often comes to us ready dressed, and it is not only from eggs we get it. As we have already found the _fibrine_ of the muscle and the _casein_ of milk in vegetables, so we shall also find there, and that without looking far, the albumen of the egg. It exists in grass, in salad, and in all the soft parts of vegetables. The juice of root-vegetables in particular contains remarkable quantities of it. Boil, for instance, the juice of a turnip, after straining it quite clear, and you will see a white, opaque substance produced, exactly like that which you would observe under similar circumstances in the _serum_ of the blood; real _white of egg_, that is to say--to call it by the name you are most familiar with--with all its due proportions of carbon, hydrogen, oxygen, and nitrogen. I wonder whether you feel as I do, dear child; for I own that I turn giddy almost when I look too long into these depths of the mysteries of nature. Here, for instance, is the substance which is found everywhere, and everywhere the same--in the grass as in the egg, in your blood as in turnip-juice! And with this one sole substance which it has pleased the great Creator to throw broadcast into everything you eat, He has fashioned all the thousand portions of your frame, diverse and delicate as they are; never once undoing it, so to speak, to re-arrange differently the elements of which it is composed. From time to time it receives some slight impulse which alters its appearance but not its nature, and that is all. As the chemist found it in the bit of salad, so he will find it again in the tip of your nose, if you will trust him with that for examination. We are proud of our personal appearance sometimes, and smile at ourselves in the looking-glass; we think the body a very precious thing; but yet when we look deeply into it we find it merely so much charcoal, water and air. This reminds me that we have not yet made acquaintance with the new personage who was lately introduced upon the scene. _Nitrogen_ or _azote_, I mean. He plays too important a part to be allowed to remain in obscurity. You have already learnt that oxygen united with hydrogen produces water. Combined with nitrogen it produces air; but in that case there is no union of the two. They are merely neighbors, occupying between them the whole space extending from the earth's surface to forty or fifty miles above our heads; together everywhere, but everywhere as entire strangers to each other as two Englishmen who have never been introduced! I should be a good deal puzzled to say what nitrogen does in the air: he is there as an inert body, and leaves all the business to the oxygen. When we breathe, for instance, the nitrogen enters our lungs together with its inseparable companion, but it goes out as it went in, without leaving a trace of its passage. Nevertheless, as sometimes happens among men, the one who does nothing takes up the most room. Nitrogen alone occupies four-fifths of the atmosphere, where it is of no other use than to moderate the ardent activity of king oxygen, who would consume everything were he alone. I can compare it to nothing better than to the water you mix with wine, which would be too fiery for your inside if you drank it by itself. This is what nitrogen does. It puts the drag on the car of combustion; as in society, the large proportion of quiet people put the drag on the car of progress (let us for once indulge ourselves in talking like the newspapers!); and such people are of definite use, however irritating their interference may appear in some cases. The world would go on too rapidly if there were nothing but oxygen among men. We have quite enough in having a fifth of it! But what in the world am I talking about? Let us get back to nitrogen as fast as we can! We must not imagine there is no energy in this quiet moderator of oxygen. Like those calm people who become terrible when once roused, our nitrogen becomes extremely violent in his actions when he is excited by another substance, and is bent on forming alliances. Sometimes the usually cold neighbor unites itself to oxygen in the closest bonds; in which case the two together form that powerful liquid, _aqua-fortis_, of which you may have heard, and which corrodes copper, burns the skin, and devours indiscriminately almost everything it comes in contact with. Combined with hydrogen, nitrogen forms _ammonia_, which is still often called by its old name _volatile alkali_; one of the most powerful bodies in existence, and one for which you would very soon learn to entertain a proper respect, if somebody were to uncork a bottle of it under your nose. Finally, nitrogen and carbon combined, produce a quite foreign substance (_cyanogen_), resembling neither father nor mother in its actions and powers, to the confusion of all preconceived ideas, when Gay-Lussac, a Frenchman, introduced it to the world, where it fell like a bombshell upon the theory of chemical combinations. This impertinent fellow, combining with hydrogen in his turn, produces _prussic acid_, the most frightful of poisons; one drop of which placed on the tongue of a horse strikes it dead as if by lightning. You perceive that you must not trust our worthy friend too far. You have learnt, however, elsewhere, that it is not equally formidable in all its combinations. Those very substances which, when paired off into small separate groups, destroy all before them, constitute, all four together, that precious aliment of nutrition of which we are formed. Moreover, its real name is "_azotized aliment_" because it is the presence of nitrogen or azote in it, which, above all, determines its quality, so that people are in the habit of estimating the nourishing power of our food by the amount of nitrogen it contains. In fact, nitrogen seems to be a substance especially inclined towards everything that has life. His three comrades wander in mighty streams, so to speak, through every part of creation; but he, except in the vast domain of the atmosphere, where he reigns in such majestic repose, is rarely met with, except in animals, or in such portions of plants as are destined for the support of animal life. On this point I will tell you the history of his original name, _azote_, which you will find curious enough. A short time before the French Revolution, in 1789, the principal properties of this gas were made known to the world by a learned Frenchman, who may be almost considered the father of modern chemistry, and whose name I must beg you to recollect. [Footnote: Dr. Daniel Rutherford (Edinburgh) discovered the existence of _Nitrogen_, A. D. 1772; but he never investigated its character.] He was called _Lavoisier_. While endeavoring to account satisfactorily for _combustion_, which before his time people explained any way they could, Lavoisier succeeded in separating our two friends, the neighbors in the atmosphere, one from the other, and was the first man in the world who managed to secure in two bottles--on the one hand, the bubbling oxygen freed from his tiresome mentor; on the other, the sober *azote, snatched away from his giddy pupil. What he did with the bottle of oxygen matters but little to us; but in the bottle of _azote_ he plunged, by way of experiment, an unfortunate mouse, and subsequently a little bird, both of whom, finding no oxygen to breathe, died one after the other. Nothing could live in it, as you may suppose; and Lavoisier thought it must be right to give so destructive a gas the name of _azote_, which in Greek means "_opposed to life_." Meantime, science went on progressing by the gleam of the lamp he had lit, and then followed the discoveries of his successors, who forced their way into the obscure laboratory where the elements of living bodies are prepared. And at last it was ascertained that this _azote_, opposed to life as it was thought to be, was actually an essential property of life; that it accompanied it everywhere, and that without it the whole framework of the animal machine would fall to pieces. It is still known by its old name, which custom had sanctioned; but I imagine no learned man can ever utter it now without a feeling of humility, and without the thought that the future has possibly many contradictions in store for him also. Besides, nitrogen has to pass through many fine-drawing processes before it attains that post of honor which has been assigned to it in the animal kingdom. The animal himself can do nothing with it, unless it has been previously absorbed and digested by the vegetable, and the vegetable in its turn could get no good from it, were it to remain isolated and indifferent in the bosom of the atmosphere. It is only when it has formed one of those combinations I have been telling you about, and more particularly the second, which produces _ammonia_, that it fairly enters upon the round of life. And then, in the mysterious depths of vegetable existence is organized that wonderful _quadrille_ of the _aliments of nutrition_, the history of which has now been sufficiently explained to you. The vegetable kingdom, therefore, is simply the great kitchen in which the dinner of the animal kingdom is being constantly made ready; and when we eat beef, it is, in fact, the grass which the ox has eaten, which nourishes us. The animal is only a medium which transmits intact to us the _albumen_ extracted in his own stomach from the juices furnished to him in the fields. He is the waiter of the eating-house; the dishes which he brings us have been given him already cooked in the kitchen. But to appreciate properly the service he renders us we must remember that the dishes to be obtained from grass are very, very small, and that it would be a great fatigue to the stomach if it could only get at such tiny scraps at a time; as, alas! has sometimes happened to the famine-stricken poor, who have tried in vain to support life from the grass in the field. But these minute dishes are brought to us in the mass whenever we eat beef, and our stomachs benefit accordingly. Do not forget this, my child; and when mamma asks you to eat meat, obey her with a good grace; if, that is to say, you wish to grow up to be a woman. LETTER XXVIII. COMPOSITION OF THE BLOOD. One word more before we finish. We must not leave off without bidding a last farewell to the good servant of whom we have spoken so much; the model steward so exact in giving back everything he receives--the factotum of the house in short. We have watched him at work long enough, but I have not yet described him personally to you, nor told you exactly what he is composed of. And here I shall be obliged to begin again with figures and calculations, although I am told young people are not very fond of them. Nevertheless, none of us can manage our affairs properly without them. Hereafter, when you are at the head of a family, you will be obliged to practise arithmetic, if you want to know what is going on in your house. Never allow yourself to look upon what is necessary as wearisome; the true secret of being punctual in our duties is to throw our heart and interest into them. I choose, therefore, to suppose that you will be interested to know that 1000 ounces of blood generally contain, (for there are shades of difference between one sort of blood and another) 870 ounces of the _serum_ I have been talking about, and 130 ounces of _clot_. At first sight one would take the quantity of _clot_ to be much greater than it really is; but in the state you see it, in the basin, it contains a considerable amount of water, which belongs by right to its companion _serum_, and which has to be drained away from it before it can be weighed. Now, in our 870 ounces of serum, we shall find, to begin with, 790 of water; do not be astonished at the quantity. Most of the weight of all animals is produced by water; they weigh comparatively nothing after being thoroughly dried in a stove--when they are dead of course--for neither animal nor plant can live unless saturated with water. This, by the way, may serve to explain the ease with which we can keep ourselves floating in water; we are not much more than water ourselves! Were it not for those abominable bones which are a little bit heavier than the rest, we should never sink unless a stone were hung round our necks. I repeat then; 790 ounces of water in 870 of _serum_, which leaves 80. Of this, _albumen_ furnishes seventy, and the ten others, with the exception of a small portion of fat which floats here and there ready-made, are _salts_. It would take too long to explain what _salts_ are here, but there is one sort of salt you know perfectly well; viz., that which is put on the dinner-table in a salt-cellar. And it is the most important of all. More than half the ten ounces of salts consist of it alone, which will make you understand better than before, what I explained with reference to the stomach; that is, why we put salt in our food. The porter above is quite up to his business when he asks everyone who enters to produce his little bit of salt. It is an attention which the blood appreciates very highly, although table-salt is of no great use to him in his building operations; but it evidently keeps him in good humor, and he would work badly without it. It is the same with all the animals man makes use of, and even the plants he cultivates, find that salt gives them an appetite. And it would almost seem as if nature had purposely dealt with us in this matter on a magnificent scale. She has made salt-magazines of the sea and the bosom of the earth, where it exists in prodigious masses which cost nothing but the labor of stooping to pick up, except in countries where a gentleman called a tax-gatherer, stands by to count the lumps and allow them to pass on by paying a duty. For my part, if I were the government--this is a secret between you and me, mind--I would look out for something else to stand in the place of the salt-tax. It is not well to interpose between man and the gratuities of Dame Nature, and to make him pay more heavily for the blood's chosen friend than she meant him to be charged. But to proceed, the kitchen-salt being deducted from the ten ounces of salts-in-general, there remain altogether from four to five ounces, which contain----. But here I stop, for it puzzles me very much how to go on! Enough, that to enable you to follow me, you would require at least as much knowledge of chemistry as will be expected of a young man who has to pass an examination in medicine. Fancy the contents of a whole druggist's shop! I will tell you a few names, that you may have a specimen of the style in use, but I forewarn you that they are not inviting: _hydrochlorate of ammonia; hydrochlorate of potash; carbonate of lime; sulphate of potash; phosphate of lime; phosphate of magnesia; lactate of soda._ I spare you the others, for many others there are, without counting those which have not yet been discovered I All these things are to be found, I must tell you, in fibrine and albumen, but in such minute quantities that it is scarcely possible to recognize them. In the serum, for instance, the gentlemen are so very small, and so completely entangled one with the other, that it is startling to think of the skill and patience requisite for making them all out, to say nothing of affixing the right name--uncouth as it may seem--to each grain of this almost imperceptible dust! He who first called man an epitome of creation, scarcely knew how truly he was speaking, for man bears about in his veins, ascertained samples of at least half the primitive substances from which all others are made, and if the whole of them should some day be found to be there, I for one should not be surprised. This is well worth knowing, is it not? and I have not come to the end of my story yet. We have still the 130 ounces of _clot_ to speak about. But their contents are easily reckoned. Three ounces of fibrine and 127 of _globules_. Here, however, we enter upon such a world of wonders, that I am quite delighted to be able to finish with it. It will be the masterpiece of our exhibition! You feel quite sure blood is red, do you not? Well! it is no more red than the water of a stream would be, if you were to fill it with little red fishes. Suppose the fishes to be very very small, as small as a grain of sand; and closely crowded together through the whole depth of the stream: the water would look quite red, would it not? And this is the way in which blood looks red: only observe one thing; a grain of sand is a mountain in comparison with the little red fishes in the blood. If I were to tell you they measured about the 3,200th part of an inch in diameter, you would not be much the wiser, so I prefer saying (by way of giving you a more striking idea of their minuteness) that there would be about a million in such a drop of blood as would hang on the point of a needle. I say so on the authority of a scientific Frenchman--M. Bouillet. Not that he ever counted them, as you may suppose, any more than I have done; but this is as near an approach as can be made by calculation to the size of those fabulous blood-fishes, which are the 3,200th part of an inch in diameter. These littlest fishes are called _globules_; but they are not exactly shaped like _little globes_, as the word would lead you to suppose. They are more like little plates slightly hollowed out on both sides. The central nucleus is surrounded by a flattened margin rather bladdery in appearance, of a beautiful red color, formed of a sort of very soft and very elastic jelly. I scarcely need tell you that all this was discovered through the microscope, and moreover, by examining the blood of frogs, in which the globules are much larger than in ours. [Footnote: Authentic portraits of these globules drawn--so to speak--by Nature herself, are to be seen on the admirable Photographs obtained by Bertsch, with the aid of the solar microscope, invented by himself and Arnaud. There you see them magnified 250,000 times, and may study them at your ease, and verify my description for yourself without any fear of being deceived. You must persuade your father to procure one. This result of photography is among the wonders of modern science.] It was in 1661--rather more than two hundred years ago--that an Italian and a Dutchman discovered, each by himself in his own country, the microscopic population of the blood. The name of the Italian is not very difficult--_Malpighi_. As to the Dutchman's, you must pronounce it in the best way you can--he was called _Leeuwenhock_. You smile, but he was nevertheless one of the first men who really comprehended what a wonderful auxiliary human science had just got hold of in the microscope, and he has helped to open the eyes of the world to the marvels of miniature creation. So content yourself, young lady, with mis-pronouncing his name, and beware of laughing at it! Names are something like faces, one may live to be ashamed of ridiculing the wrong one. This discovery of the globules of the blood, was destined to throw great light upon the way in which the _nutrition of the organs_ was carried on. Modern chemists, who are always fond of investigation, have examined what they are made of, and can find little else in them but _albumen_. Out of our 127 ounces of globules, 125 are albumen; and these, with the 70 ounces which we found before in the serum, make up the 195 ounces (of albumen) which I told you were contained in the 1,000 ounces of blood. Forgive me all these ounces and figures. Exact accounts give exact information. These globules, then, are composed almost entirely of albumen. Nearly two-thirds of all the albumen in the blood is concentrated in them; and you know now the use of albumen, viz., that it is the foundation of all the buildings of which the blood is the architect. Everything leads us to believe that the formation of globules in the blood is the last touch given by nature to that magical provision begun in thevegetable, continued in the stomach, and finished in the veins, to which, in combination with carbon, hydrogen, oxygen, and nitrogen, we are indebted for the subsistence of every portion of our body. Thus the blood-globules may be considered as albumen which has finished its education, and is ready to go into the world; while the albumen of the serum is, like our young friends, the generations in reserve, who are still at school awaiting their turn. This is more than a mere supposition. Scientific men have taken to themselves, on their own authority, all sorts of rights over animals, and we profit basely enough by their crimes--I will not withdraw the word--in order to increase our knowledge. Accordingly, they conceived the idea of opening the veins of animals, and allowing the blood to flow until the victim was prostrate and motionless as a corpse. This done, they proceeded to fill the exhausted veins with blood, similar to that which had been withdrawn, and with the blood, life was seen gradually to return, till the animal rose from the ground, walked, and resumed its disturbed existence, as if nothing had happened. The interesting part of the experiment to us is, that if serum only, without globules, be restored to the unfortunate animal, it is of no use whatever, and the corpse does not revive. It is evident, then, that all the power and virtue of the blood lies in the globules; and according as their number is great or small it is "rich" or "poor," as it is called; and where their number is not up to the mark, the blood acts more feebly on the organs, life is calmer, and people are no longer troubled with emotions--in other words, with violent heats of the blood. Hence the impassible character of _lymphatic_ people, who often get on in the struggle of life better than others, because they are never in a hurry, and know how to wait for opportunities. You will occasionally hear the word _lymphatic_, for it has become the fashion, and it is time for me to explain it; but unluckily the explanation is not in its favor. You remember those little scavengers we spoke about formerly, who came from the depths of all the organs, carrying away with them the worn-out building materials, and covering the surface of the body with an inextricable net work of tiny canals. These canals are called _lymphatic vessels_, in consequence of being filled with a liquid which is called _lymph_ (_water_, in Latin), but why I cannot tell you, for it is, in fact, simple _serum_. There was a very simple way of ascertaining this by making out an inventory of the contents of the _lymph_ liquid, and when this was done, they were found to consist of water, albumen, and the salts of serum; there was even a little fibrine; the only thing wanting was _globules_. How the truant serum finds its way into the lymphatic vessels is probably as follows:--I have already mentioned the inconceivable delicacy of the capillary vessels, those last ramifications of our arteries and veins. It needs all the impulsive power of the heart to enable the blood to force its way through these narrow passages; and minute as are the globules, it would seem that they have but just room to pass, for in examining under the microscope a corner of the tongue of a live frog, the globules have been seen doubling themselves up to pass through the capillaries, resuming their natural form afterwards. It was this, indeed, which made me tell you just now that their margins were elastic. During this momentary crush, part of the serum being forced on too fast, oozes through the wall of the over-filled capillaries, as water oozes through the leathern pipes of a fire-engine, and hence probably the appearance of serum or _lymph_ in the organs, where it is immediately sucked up (i. e., _absorbed_) by the lymphatic vessels. Now, you will easily understand that the larger the proportion of serum in the blood, the greater will be the quantity to be expelled in passing through the capillaries, and the more will the lymphatic vessels swell. In such cases the temperament or constitution is said to be _lymphatic_. If, on the contrary, the globules are in excess, the lymphatic vessels receive less serum, and diminish in size. The temperament is then called _sanguine_, as if there were no serum in the blood. You shall be judge yourself, knowing what you now do, whether it would not be more reasonable to call such temperaments _serous_ and _globulous_. At any rate those names would give people an idea of the real state of things, and teach them that there were such things as globules in the blood. [Footnote: Here is a summary of the contents of 1000 oz. of blood:-- Ounces. Water................... 790 Serum. Albumen...................70 870 Salts.................... 10 Fibrine................... 3 Clot. Globules Albumen.. 125 130 Coloring matter...... 2 127 ---- 1000 ----] To conclude, I must give you an account of the two ounces which still remain of the 127 of globules, albumen taking up only 125, as you know. Those two poor little ounces--the remainder of the thousand with which we started--would you believe it?--they alone have the honor of conferring upon the blood its beautiful red color. They constitute the coloring matter of the globules, and you will never guess its chief element. It is iron; ay, actually iron, young lady--the iron of swords and bayonets. We often accuse it of tingeing the earth with blood; and you may now know further, that it reddens blood itself by way of compensation. Do not trouble yourself as to where it comes from. Our fields are full of it, our very plants have stores of it. It sometimes happens that our digestive apparatus, put out of order by other occupations, fails to make use of the amount of iron offered to it; in which case the blood is discolored, and the face turns pallid as wax: this is an illness requiring great care. If it should ever befall you, you will not be surprised, after to-day's lesson, to hear the doctor say that you must have some iron. But be easy--you will not have to swallow it whole! If you will take my advice, you will obey the doctor's orders as soon as you can. Not that looking pale signifies any thing: indeed, some young ladies think it an advantage. But it is no advantage to any body when the blood-globules are distressed for want of their proper supply of iron, and do their work grudgingly, like ill-fed laborers. Nothing can go on without them, you know, and they are people whom it is not well to leave too long out of sorts. Else languor comes on; languor which is the beginning of death: and pray remember that iron, which so often causes death, is equally useful for keeping it at bay. By sending it to the discolored globules, you give them back their energy and brilliancy together. I have come here to the end of all that is known with any certainty about these wonderful globules which are to us the medium of life. Shall I go further, is the question, and take you with me into the fields of supposition, so full of noxious weeds? And yet why not? Science owes its present position to the praiseworthy rule of never adopting any theory which is not supported by well-established facts; and I would be the last to advise a change. Were I to tell you, what I am now going to say to you, at a meeting of the British Association of Science, they would turn me out of the room, and with very good reason. Nothing ought to be taught there but what can be proved. But this is of no consequence to you and me, and we have a right to amuse ourselves a little, after having worked so hard. Well, there is an idea which nothing shall ever drive out of my head, however imperfectly it may be proved as yet; namely, that each of our globules is an animated being; and that our life is the mysterious result of these millions of lesser lives, each of them insignificant in itself; in the same way that the mighty existence of a nation, is a compound of crowds of existences, each, for the most part, without individual importance. Take our own or any other country as an instance; where millions of brains, many of them by no means first-rate in power, go to form a national character, the highest (as each _nation_ is apt to think of itself) in the world. According to this idea, you must be a sort of nation yourself, my dear child, which is gratifying to think of on the whole. This is much more extraordinary than what I told you some time ago, of the individual life of the organs, each of which on this new system would be a province in itself! Do not exclaim too hastily. Whether the globules are animated or not, it is very certain, let me tell you, that your life depends entirely upon them; that it is weakened if they are weakened; that it revives with them; and that whether you attribute individual life to them or not, makes no alteration in the fact: their action upon you remains the same. And he must be a very clever man who can show me the exact difference between action and life. Hereafter, when we have descended the scale of the animal world together, and are arrived at the study of what are called microscopic animals, you will better understand the words which appear so strange to you now. What little our feeble instruments have revealed to us so far, of the history of those globules, places them almost on a level with those strange creatures, inexplicable to us, which are found in innumerable multitudes, in a variety of liquids. We trace in them the beginning of organization; their form and size are alike in all individuals of the same species; and species vary enough to induce one to believe, that there is a necessary relation between an animal's way of life and that of its globules. If the microscope has not yet caught them in any overt living act, who can be surprised? it is only dead blood which has been submitted to the test. They ought to be observed in the exercise of their functions, in the living animal itself, as has been done to some extent in the frog; and if our foolish chat could influence scientific observers, I would say to them what M. Leverrier said years ago to the astonished astronomers: "Look yonder; you ought to see a light there with which you are not yet acquainted!" I am carrying you a long way on the wings of my fancy, my dear child; but have no fears; I will not let you fall. This life of our globules, which would, after all, be only one mystery the more among many, opens before our eyes a magnificent vista of the uniformity in the scheme of creation; which goes on repeating itself, while enlarging its circles to infinity. We may, all of us, be only so many globules of the great invisible fabric of humanity, in which we go up and down one after another; and those vast globes which our telescopes follow through celestial space, may be but globules of one, as yet unknown, to which the Almighty alone can give a name. Take this page to your father, my dear child, if you do not understand it rightly; and now, shake hands, my history is ended! PART SECOND--ANIMALS. LETTER XXIX. CLASSIFICATION OF ANIMALS. 'It is dangerous to show man how much he resembles the beasts, without at the same time pointing out to him his own greatness. It is also dangerous to show him his greatness, without pointing out his baseness. It is more dangerous still to leave him in ignorance of both. But it is greatly for his advantage to have both set before him.'--_Pensées de Pascal_. The man who wrote that, my dear child, did not trouble himself much about children. He was one of the gravest specimens of literary genius--a man who can scarcely be said to have ever been a child himself; for as the story goes, he was found one day, when only twelve years old, inventing geometry, and his father only saved him from trouble, by putting the great book of Euclid into his hands; and, at sixteen, he wrote a treatise on _Conic Sections_, which was the wonder of all the learned men of the day. I have not a very clear idea of what Conic Sections are myself; but I tell you this to show that Pascal was a very profound and learned man, under whose authority, therefore, I am very glad to take shelter, now that I am going to set before you the very startling points of resemblance which exist between you and the beasts. As to your greatness, it delights me to explain it to you. It is not due to the handsome clothes you wear when you are going out, nor to the luxurious furniture of mamma's drawing-room, but to the possession of that young soul which is beginning to dawn within you, as the sun rises in the morning sky, and pierces through the early mists; in that growing intelligence which has enabled you to understand so far all the pretty stories I have told you; in that fresh unsullied conscience, which congratulates you when you have been good, and reproves you when you have done wrong: all of them gifts which are not bestowed on the lower animals, or certainly not to the same extent as upon you--gifts by which you rise more and more above them, the more they are developed in yourself. Your baseness--but, begging Pascal's pardon, I cannot call it baseness--your connecting link with the brute creation lies in those other gifts of God which you and they share in common--in those wonders of your organization, which we shall now meet with in them again, in full perfection at first, and that in every respect; by which fact you may learn, if you never thought of it before, that the lower animals come from the same creating hand as yourself, and ought to be looked upon to some extent as younger brothers, however distasteful such a notion may seem at first. Societies have been established of late, both in France and England, for the protection of animals; and a noble and honorable task they have undertaken, in spite of the jokes that have been made at their expense. It is a mischievous cavil to tell people who are doing good in one direction, that more might have been done somewhere else. Everything hangs together in the progress of public morality, and you cannot strike a blow at cruelty to animals without at the same time making a hit at cruelty to man. And the best argument in favor of the rights of beasts to protection, will be found in the tour you and I are now going to make together through the different classes of the animal creation. Let us begin with the horse--one of the beasts which oftenest needs our protection. Give him the mouthful of bread whose history we have just finished. He accepts it as a treat, and needs no pressing to eat it. And if it could tell you all its adventures afterwards, you would find that you were listening to precisely the same story as your own over again; that nothing was different, nothing wanting. First of all--teeth to grind it, and a tongue to swallow it with, as a matter of course. Next a _larynx_, which hides itself to avoid it, and an oesophagus,* which receives it, just as in your case; a stomach with its _gastric juices_, the same as yours, in bagpipe form, and its _pylorus_, like your own; a _lesser intestine_, into which bile pours from a liver like yours; _chyliferous vessels_ which suck up a milky chyle, as with you; farther on a _large intestine_; and so on to the end. Nor is this all:--the horse has also a heart, with its two _ventricles_, and its double play of valves; a heart which the little girl in our tale might confidently have exhibited to the engineers as her own, but that it would have been somewhat too big, of course; into which heart, as into ours, comes _venous_ blood, to be changed afterwards to _arterial_; in lungs to which the air keeps rushing, forced thither by the see-saw action of a _diaphragm_, as faithful a servant to him as to you. And those lungs like our own, are a charcoal market: the same exchange takes place there, of carbonic acid for oxygen, as in ours, an unanswerable proof that the stove inside the horse burns fuel in the same way as our own: and if you were to place the thermometer inside his mouth (for we are polite enough to call it his mouth), it would mark 37 1-2 degrees of heat (centigrade)--a difference from ourselves not worth mentioning. Finally, if you examine his blood, you will meet with the same _serum_ and _clot_, the whole company of _hydroclorates, phosphates, carbonates, &c._, from which we shrank before, and globules made like your own; having the same construction, and the same life, or action, if you like it better. I need scarcely add that 100 oz. of its _fibrine_ and _albumen_ contain: Of carbon......... 63 oz. Of hydrogen........ 7 This is understood all along as being the case everywhere, from man down to the turnip; so that, like you, this noble animal, as the horse is called, is in point of fact only so much carbon, so much water, and so much air, joined to a handful of salt, which represents the earth's share in the bodies of animals. You must confess that, if we cannot quite call the horse a fellow-creature, he is nevertheless very like us. And it is the same with all those animals which man makes use of as his servants, and which have really a sort of right to the protection of society, since they form, to a certain extent, a portion of the human family. I do not speak here of the dog, who pays his taxes, poor fellow, in his quality of friend to man. When I think of the almost identical organization of man and his next-door neighbors, I am astonished how it could possibly have come into the head of a certain learned individual (I will not mention his name), when drawing up a plan of natural history, to give to man a separate kingdom, as a sequel to the three kingdoms already established--the mineral, vegetable, and animal. One might have forgiven Pascal if such an idea had got into his head after writing his treatise on Conic Sections; there being nothing in them to throw light on such a subject. But in a naturalist, an observer who had spent his life in the study of living creatures, the thing seems almost incredible. Possibly he had reasons for what he did, but he certainly did not find them in the subjects of his studies. Forgive me, my dear child, for forgetting you in this fit of indignation upon a point you cannot care much about. It leads me naturally enough to my present business, which is none of the easiest, but you must help me by paying attention. I am going to describe the _classification of the animal kingdom_. There are a terrible number of animals, as you know; and if we wish to study them to any real purpose, we must begin by introducing some sort of order into the innumerable crowds which throng, pell-mell, around us for observation. We should otherwise never know where to begin, or when we had come to an end. There are many ways of setting a crowd in order, but they all go upon the same plan. The individuals composing the crowd are parcelled off into companies, each company having a distinguishing mark peculiar to those who compose it. Thus the first division is into a few large companies, which are afterwards subdivided into smaller ones, and those into others still less, until the divisions have gone far enough. And this is what is called a _classification_. Let us imagine, as an example, a large crowd in a public garden; I will soon classify it for you. I shall put the men on one side and the women on the other. Then--to begin with the women--I shall subdivide them into married and single. Then among married women I shall make a company of mammas, and another of those who have no children. Among the unmarried I shall have a group of those who have never been married--girls, that is--and another of widows--those who were once married, but are so no longer. Then, following the girls, I shall separate them into tall and short. And among the short ones I shall divide the brunettes from the blondes, and so I shall get at last to a little blonde girl, whose classification (were she a soldier) in military rank would be as follows:--_squadron_ of blondes; _company_ of shorts; _battalion_ of girls; _regiment_ of unmarried women; _division_ of women. The division of men could be carried out in the same manner; and thus we should classify our mob into complete military order. This is easy enough, however; but the classifying of animals is a very different affair, and I will tell you why. We ourselves require a classification to study them by, though none was needed for their creation. The Almighty has formed them all on one uniform plan, around which He has, if I may so express it, lavished an infinity of modifications separating species from species, yet without placing between the different species those fixed barriers which we should require now to enable us to classify them strictly. You who are learning the pianoforte have perhaps been told the meaning of a _theme_ of music--the first idea of the composer who follows it throughout the piece from one end to the other, embroidering on it, as on a bit of canvas, a thousand variations melting one into another. Such is pretty nearly, if we may venture the comparison, the way in which we can picture to ourselves the Almighty moving through the work of animal creation. Step in afterwards and divide away into regiments and battalions, if you please. Nature permits it, but she will never, to accommodate your classifications, separate what in her is really united. There is still a way, however, and that is to do as I did just now in the case of the crowd. To take, viz., only one _character_ (as we call a distinguishing mark in natural history), and to throw together all the individuals which possess it, the blondes, the shorts, the girls, &c. In this way it may soon be done; but what is the result? You are in one class, your eldest sister is in another, your mamma in a third, and your brother in a different division altogether, a long way from you all. Such a classification is called _artificial_, and you can see at once that it is worthless. The most natural plan is to put together those that are of the same family; and the classifications made on this principle are called _natural_ classifications. It is a classification of this sort which has been adopted for the animal kingdom. People have taken all the animals which possess in common not one character only, but a collection of characters of the most important kind, _dominant characters_, as they are called; and of these animals they have formed, to begin with, large primary groups; subdividing these afterwards according to the secondary differences, which distinguish different species in the same group from each other. In this manner all the different sorts of animals are included in different systematic divisions of one vast whole, through which it is easy to find one's way, because there is a beginning and an end; and in which animals of the same family are always grouped side by side. Were I to mention all the divisions of this immense classification at once, you would find the account a little long, and not very amusing. We will go through them by degrees therefore, and, to simplify matters, will, throughout the whole, only consider those particular characters which are connected with our special study, the nourishment of life, that is to say: so that you will always find yourself on well-known ground. I must tell you once for all, however, that it is with this as it is with grammar. Here and there are--and it cannot be avoided--certain exceptional cases which keep protesting timidly against the arbitrariness of rules; but no matter; we must be contented with what we can get, and be grateful into the bargain to those who have given us this skillful classification, at once so ingenious and useful, in spite of its inevitable imperfections. What is impossible is expected of nobody. You could not understand, even if I wished to explain it to you, the amount of science, labor and genius requisite for making out that long list, which, tiresome as it may seem to children, is absolutely beautiful in the eyes of learned men; too beautiful, perhaps, and I will tell you why when we have finished. Meantime, as the best reward we can give to those who have done us some great service is to teach their names to children, I will tell you, before bidding you good-bye, to whom we owe this classification, the details of which I do not enter upon to-day. In the first place, we owe the method employed in its establishment, the method of _natural classification, i.e._, to a learned man of the last century--a learned Frenchman, Bernard de Jussieu--who tried it upon plants; another large flock by no means very easy to put in order, as you may convince yourself any day by studying botany. The man who applied this system to animals was also a learned Frenchman, the clearness of the French mind adapting them peculiarly for that sort of work. And he, too, is one of the glories of that nation. His labors and discoveries gave a perfectly new impulse to the study of nature. It was George Cuvier, whose statue you may see at Montbéliard, if you should ever go there. Not that Cuvier carried through this gigantic work alone, though the credit of it is justly his due, he having directed and inspired it. He was assisted by many. But among his assistants there was one, Laurillard, the most modest, yet the most active of all, whose name I will mention also, because, like the others, more or less celebrated, he has never had his reward. [Footnote: In the earlier editions of this work, there was, in this place, a severe reproach upon Cuvier for not having given proper credit to Laurillard. This reproach I have since learned was unjust. M. Valenciennes himself, one of the most illustrious of the collaborators of the great Cuvier, has written me a letter in which he defends the reputation of his friend with a warm indignation which does honor to both of them; and cites passages in which Cuvier has spoken of Laurillard, and among others, in the third volume of the _Ossements Fossiles_, p. 32, ed. of 1822.] It only remains for me, therefore, to let the lash, which I was laying upon the shoulders of another, fall now upon my own, and to deplore the too great facility with which I had credited, without sufficient proofs, an assertion which I had otherwise good reason to believe to be exact--coming to me, as it did, from Montbéliard himself, on the testimony, it is said, of the family of Laurillard. From this avowal, a little painful, I confess, my young readers may learn the inconvenience of rashly condemning others! As I said in the concluding passage, which truth, only too late, now compels me to suppress--"The truth is sure to come out at last." LETTER XXX. MAMMALIA. (_Mammals_.) Do you remember of my talking of the _vertebral column_ when I was describing that great artery, the _aorta_, to which it forms a rampart of defence? I should not have named it without explanation, but that you had only to pass your hand down your back to find out what it was. Now the _vertebral column_, or backbone, is one of those _dominant characters_ which always carries along with it a train of other points of resemblance in the animals where it is found. It has been chosen, therefore, as the rallying-point of the first great group. I must tell you beforehand that there are four of these groups, four large companies, _i.e._, which naturalists have called by various names; as Groups, Sections, Primary Divisions and even Branches; in this case comparing them to four great branches of a tree, going off in different directions from the same trunk. And, first of all, we have to begin with the group of the _Vertebrata_--vertebrata animals--vertebrata being a word which explains itself. Of course we ourselves belong to this group. In fact, we are at the head of it; but it descends far below us. It goes on to the frog and the fish, and includes the monkey, the ox, the fowl and the lizard; for all these creatures possess the vertebral column. The frog does not appear to be very much like us at first sight; and yet, by virtue of its vertebra, it has its points of resemblance to us, which are worth the trouble of considering. Vertebrated animals are all furnished with a head, containing a brain, which gives its orders to the whole body; they have all an internal skeleton, that is to say, a system of bones linked together, forming a solid base by which all the organs are supported. I was going to add that they have all four limbs; but here the serpent glides in to call me to order, and to hiss at our childish craving for fine-drawn divisions, in perfect order, where there is an exactly proper place for everything. However, each has, without exception, a heart, with its network of blood-vessels; red blood, under its two conditions of arterial and venous; and also a digestive tube, acting, on the whole, pretty much like our own. I do not insist, mind, upon this last point, viz., that of the digestive tube; for we shall see, by-and-by, that it is a character beyond the pale of the primary groups. It is the fundamental character of the trunk itself, which necessarily exists, therefore, in all the groups; and, as I told you in my first letter, you will find it everywhere. This is--to let you into the secret at once--the theme on which the Great Composer has based all His infinite varieties of animal life; and herein lies the uniformity of the animal creation, that startling uniformity which has given so much offence to many learned men, and which is so obvious that it will strike you of itself, I feel sure. But I reserve this subject to the end of my letters, when you will have heard all, and be able to judge for yourself. It would be plunging back into confusion to attempt to examine all the vertebrated classes at once. After making a division you must go on. The groups have, therefore, been subdivided into _five classes_, which we will study in succession, only naming each now: viz. _mammals_, _birds_, _reptiles_, _fish_, and _batrachians_. Do not alarm yourself at this last name: it is a Greek word, meaning simply frogs. The mammals are our immediate neighbors. Mammalia are the animals which produce milk. They bring forth their young alive, and give suck to them as soon as they are born. This was your first nourishment, my dear child, so you yourself are a little mammal. What I said to you in the last letter about the horse, applies pretty nearly as well to all mammals. We shall not, therefore, have any great variations to notice here. Nevertheless, as these are the animals which interest us most nearly, as they are in fact our nearest of kin, so to speak, and those with whom we have the most to do, we will now pass in review the different orders of which their class is composed. I must explain to you that the _classes_ are subdivided into _orders_, the orders into _families_, the families into _genera_, the genera into _species_; as in armies divisions subdivide into regiments, regiments into battalions, &c. It became necessary, moreover, to make use of special names, in order to make these subdivisions comprehensible, and the following are those which have been adopted. ORDER 1. _Bimana (two-handed)_. Here we may pass on at once, for we have discussed this order enough already. We are _bimane_ ourselves, since we have the distinction of possessing two hands. Yes; that is the pretty title which the professors have been so polite as to give us, instead of leaving us simply our proper name of man. Yet it would have been very easy to do this, seeing that we are the only family, the only genus, and the only species of the order. In railway travelling, people of distinction have a reserved carriage to themselves: so we decidedly deserve an order to ourselves; but that is not quite the same as a separate kingdom. In short, you are a _bimane_; so make the best you can of it. ORDER 2. _Quadrumana (four-handed)_. These, as their name indicates, have four hands: two at the end of the arms, and two at the end of the legs; such are the monkeys. There is nothing to remark; they are all alike. Stay; I am wrong, though: there is something, insignificant it is true, but still pointing to deviation. In some the canine teeth are set forward, _i.e._ project, and are longer than the rest, and some species, as the ape, for instance, have just under their cheeks convenient little pockets, which open into the mouth, and in which they can deposit a reserve of nuts to be devoured at leisure; these are called _pouches_. It is a trifle in itself, but we have here a first example of the eccentricities of nature in the construction of animals. At one time she adds a detail; at another she suppresses one. Sometimes she is pleased to enlarge an organ, as in the canine teeth of the monkey; sometimes she reduces it; or perhaps here she makes its construction more simple; there again more complicated: but still it is always the same organ. So the dressmaker shapes the sleeves of a dress, sometimes open, sometimes closed, flat or puffed, plain or ornamented, pagoda-shaped or gigot-formed: but still they are all of them sleeves. ORDER 3. _Cheiroptera (wing-handed)_. I am quite ashamed of offering you such a word as this, my dear child. It was a Greek fancy of the learned men, who would not condescend to use the vulgar name Bats. In the Greek, _cheir_ means hand, and _pteron_ wing. The Cheiroptera are animals with winged hands; in fact, the fingers which terminate the fore-limbs of the bat lengthen as they spread out to an extravagant extent; and are connected together by a membrane springing from the body, with which they beat the air as with a wing, and which enables them to fly with such ease that theyare often taken for birds. But, so far from really being a bird, this curious little creature has the same internal organization as ours, and indeed comes so near us, though without looking as if it did, that a scientific man, and a very distinguished one too, placed the bat in the first family of the animal kingdom, with the monkey, and, you will hardly believe it, with man. It is found that the bat, like man and the monkey, suckles its young at the breast; and it was this very character which Linnæus, the leader of artificial classification, thought of selecting as the distinguishing mark of his first family in the animal kingdom. It is true that in honor of the human race he had given that first family a much more sonorous name than our usual one of _man_--viz. _primates_, the first in rank--that is, the princes. But, alas! we were to be princes on an equality with bats; and, for my own part, I prefer being a _bimane_, and alone. I really believe that it was to put this saucy little creature back into its proper place that, at the time of the great revolution in favor of natural classification, the conclave of professors assembled at the Botanical Gardens in Paris inflicted this horrid name of Cheiroptera on the bat, ejecting it contemptuously from the overthrown dynasty of the _primates_. I have not been sorry to make you acquainted as we went along, with this little trait in the history of classification; but beyond it there is really nothing particular to say about the apparatus for the nourishment of the deposed bat-princes, which is a plain proof how nearly it must be like our own. By-the-by, there is one trifling remark to be made with regard to her teeth. The bats we have in our country (France), for there are many varieties of species in the world, live on insects, which they catch in their flight by night. These insects are often enveloped in a very hard outer case, which molars like ours would have some difficulty in chewing properly; consequently the molars of our little friend are fringed with conical points, and with these she grinds down her prey without difficulty. In America there is a large bat, the vampire, which lives on the blood of animals, and nature has armed it accordingly. It has at the extremityof its muzzle two sharp beak-like incisors, like the lancets of a surgeon. The vampire bat, which roams by night like other bats, goes straight at the large animals it sees asleep, delicately opens a vein in the throat without waking them, and sucks their blood in long draughts, taking care, by fanning them with its wings, to lull them into a cool and balmy slumber. It does not, as you see, make a savage attack on its victim: it merely inflicts a bite like that of the leech, but the result may be death. This is the best emblem I know of the sycophant, who undermines your soul while he fans your vanity; and observe, while we are on the subject, that this species has always had the art of insinuating itself among princes. ORDER 4. _Carnivora (flesh-eaters)_. When translated into English, this word needs no explanation. And here we have the tribe of bears, wolves, foxes, weasels, dogs, cats, tigers, lions, of all the fighting animals, _i.e._, those which steep their muzzles in blood, and live by devouring others. These have a similar apparatus for nutrition to our own; especially the bear, who, with the monkey, is the animal most nearly resembling man, seeing that he has feet like ours, with scarcely any tail, while the monkey has our hands, without specifying any other points of resemblance. Like ourselves, too, the bear is omnivorous; that is to say, it eats everything, vegetables and fruit as well as meat; and nature, which has given it our diet, has furnished it with molars almost exactly like our own. Its canine teeth alone differ from ours: they are more prominent even than those of the _quadrumana_; and this is the case with all the members of the order, in whom we find them sometimes developed into actual daggers. But those of them which are purely carnivorous have molars peculiar to themselves. The lion, for example, who does not share the bear's taste for carrots, and who would die of hunger surrounded by the honey and grapes of which the bear is so fond--the lion, who never takes anything but raw meat between his teeth, has molars furnished with sharp cutting edges, intended to slice the meat like the chopping knives used by cooks for making a hash. The lion offers another peculiarity, which is common to him with all the _Carnivora_. Place your finger close to the lower end of your ear, and work your jaw; you will feel something hard moving backward and forward against your finger. This is where the lower jaw is set into a bone of the skull, called the _temporal_, if you care to know its name; in other words, the bone of the temple. The extremity of the jaw bends, and forms a kind of little knob, called _condyle_, which fits into a cavity of the temporal bone. With us the cavity is not very deep, nor the knob very large, so that it can play very freely; and it is this which allows us that second movement from side to side, of which I spoke to you formerly, and thanks to which, our little mills reduce a mouthful of bread into paste. But this freedom of action has also its inconveniences. You must never attempt to force too large an article into your mouth at once--an apple, for instance--the efforts you would then be obliged to make might easily cause the _condyle_ to slip out of its little cavity, where its hold is but slight, and to get under the _temporal bone_; and there you would be with your mouth wide open until the doctor arrived. The lion, whose voracious jaw opens like the door of an oven, so that the tamers of wild beasts have no scruple in thrusting in their whole heads, a mouthful a good deal larger than an apple; the lion, who has no doctors, would often be liable to this accident--an irremediable one in his case--if nature had not made a special provision for him. In order to secure greater firmness and strength, the second movement is in his case sacrificed by embedding the _condyles_ deeply in their cavities, where they are fastened in such a fashion that they can only move up and down, like the handles of a pair of pincers. This is a restraint which enables the jaw to be safely thrown open as wide as the fiery impulse of its terrible proprietor impels it. Less freedom, in exchange for more power, is a bargain which any one would gladly accept who plays the part of a lion! I have here a remark to make. We have now passed in review three orders besides our own, and have only had to point out a change in the fastenings of the jaws and in the teeth; and you will find that the same sort of modifications take place in the whole class of mammals. This is in fact the essentially movable and variable point in their apparatus for nutrition. The jaw and its weapons vary their character from one species to another, according to the nature of their food; but the modifications generally terminate there, _i.e._ on the threshold, as it were. The interior arrangements of the house remain otherwise much the same in all. Here, however, in the lion, there is an interior change to be described; but not in the arrangement of the parts, only in their size; the stomach in this species being even smaller and weaker in proportion than ours, and the digestive tube more than twice as short. The digestive tube of an ordinary sized man is about seven times the length of his body, whilst that of the lion only measures three times the length of the animal. This is a natural consequence of the kind of nourishment he takes. Flesh and blood, on which he lives entirely, is concentrated _albumen_, prepared beforehand in the bodies of his victims; so that no great preparation is needed here to convert it into lion's blood. A professor of chemistry, who has a good assistant, does not need a very large laboratory. This is the case with the lion; and nature, which makes nothing in vain, has here economised space. Tame the monarch of the forest into a domestic animal, and change his food, and I will wager anything you please that, in the course of a few generations, his digestive tube will lengthen itself. Examine the inside of the cat, his little cousin, formed originally on the same pattern as himself, and, without having ascertained the fact myself, I am sure that, by dint of feeding it daily on sops and milk from generation to generation, its digestive tube has become more than three times the length of its body. Here you ought to be told at once a very important fact relative to the organization of the lower animals, one which places them all very far below the order of _Bimana_, since there is such an order. In bestowing intelligence and freedom of action on man, the Almighty has given him the unspeakable privilege of working in His footsteps--if I may presume to use the expression--of following up His work of creation as it came from His hand. Now especially that man begins to see a little more clearly into the laws of life, he has entered more directly into the possession of this almost divine privilege, which the Almighty has graciously vouchsafed him. You can even now have an ox or a sheep made to order in England, giving your dimensions, as if you were ordering a cabinet; and in a few years, if you have not asked actual impossibilities, your commission will be executed to within an inch. This is not said in reference to the _Carnivora_. But in bidding you good-bye, my dear little mammal, I could not bear to leave you under the weight of that debasing title: I wanted also to show you your greatness. LETTER XXXI. MAMMALIA. _(Mammals)--continued_. Let us continue to pass in review the different orders of the class Mammalia. We may meet elsewhere with facts more important to science, but nowhere with any so personally interesting to ourselves. ORDER 5. _Insectivora (insect-eaters)_. This order devours insects, as their name tells you plainly enough. They feed in the same manner as the bats; consequently they have molars like theirs, as was necessary. It is an unimportant little family, and we will not waste much time upon it. The chief of the order is the hedgehog, a native of our country--not very large, about nine inches long--which lives in the woods, and which when rolled up into a ball, with all its quills standing out, looks very much like an enormous horse-chestnut in its shell. Its canines have not much work to do, consequently they are very small; but, on the other hand, its two front incisors are prolonged beyond the others, the better to seize its prey, which creeps upon the ground. Internally there is nothing to remark upon. Next to the hedgehog I will mention as a curiosity the shrew or sand-mouse, which, in spite of its name, is no mouse at all, but has the honor, if honor it be, of being the smallest animal known of the class Mammalia. It is about two inches in length altogether; and if you carefully examine its little body, you will find that it contains all the organs you possess yourself--oesophagus, stomach, liver, intestines, veins, arteries, heart, lungs--nothing is wanting: the machinery is absolutely the same. ORDER 6. _Rodentia (rodents)_. Were we to translate this word into its meaning, namely, the _Gnawers_, there would be some comfort in it, for we would at once know what it means: but no matter. Rodents, or Gnawers, are rats, hares, rabbits, beavers, marmosets, squirrels, in fact all the creatures which _nibble_. To _nibble_, if you do not exactly understand the word, means to chew with the points of the teeth. The rodents have no other way of eating but by filing, if one may so say, their food with the points of two incisors with which both the jaws are provided; these incisors are very long, much longer even than those of the hedgehog. The next time you see a rabbit at table, ask to see the head; and you will find that it has four pretty little teeth, very sharp, shaped like a joiner's chisel; that is to say, with a "bevelled edge," to use the received expression; in other words, with one edge thinner than the other. Here, then, we begin to diverge from the old model. First, there is a different fastening, or _articulation_, as it is called, of the jaw. Its _condyles_, which we saw just now in the _Carnivora_ enlarged transversely and deeply embedded in the _fossae_ or cavity of the temporal bone, extend here longitudinally; an arrangement which enables the jaw to move backward and forward at pleasure, like the arm of the locksmith when using the file. Furthermore, those little teeth, which are constantly rubbing against each other, would be very soon worn out, if, like our own, they were made once for all; accordingly their germ, or _pulp_, to use the proper term, instead of perishing, as with us, when the tooth has once come, retains its life, and works on throughout the life of the animal. They sometimes say of a man who has not eaten for a long while, that his teeth have grown long. This is a joke with us; but in the case of a _rodent_ would be too serious a matter to be a joke; for, as their incisors are always growing, like our nails, they would soon become too long if the animal ceased for any length of time to wear them down by eating. It is for this reason that rats and mice have such incessant appetites, and that with them "all is fish that comes to the net;" old books, rags, and even planks of wood, which they will gnaw for want of something better. Come what may, they must keep up at an equal rate the wear and tear of the incisors, and the internal growth of the pulp beneath, which is always pushing the tooth forward. This dull continuous work might otherwise have a terrible result, which you would never suspect. It is very disastrous for a young lady to lose a front tooth, as it is called, for it sadly spoils a pretty face; but for a _rodent_ such a loss is much worse; in fact, it is a death-warrant. The corresponding tooth, having no longer anything to rub against, ceases to wear out; and as it does not stop growing on this account, it lengthens indefinitely, until at last it pushes out beyond the mouth, and places itself like a bar between the two Remaining teeth and the food of the animal, who, poor beast, being unable to eat, ceases to live. The canines, whose duty it is to pierce the food, have, of course, no use in a jaw that grinds, nor are they to be found there. Between the incisors and the molars there is a large vacant space, which you will easily detect if you examine a rabbit's head. Finally, animals which can fall back in time of need on a plank for their dinner, require a very different-sized cooking apparatus to that of the _Carnivora_. Thus the rat, the most perfect sample of the rodent order, possesses a digestive tube of a prodigious length, through which the scrapings of wood have plenty of time for travelling, while the minute nutritive particles they contain are being thoroughly disengaged; and as every part of the animal organization tends towards keeping our insatiable rodents in the constant state of voracity required by its inexorable pulps, nature has given it an enormous heart whose size exceeds even that of its stomach. Perhaps you do not catch at once the connection which exists between the size of the heart and of the appetite; yet it is very simple. Large barrels are requisite for those who brew a great deal of beer, and large hearts for those who make a great deal of blood. Now, it is the blood, as you know, which carries heat; in other words, life, throughout the body; when it pours in in torrents, the fire goes twice as fast, and, consequently, the feeding must be kept up. A medical friend of mine told me that he once had some rats sent to him--a boxful in fact--for one of those scientific experiments which one would venture to condemn more earnestly if their results were not sometimes beneficial. Next morning there were only two or three animals to be found, and these had eaten up the others. See the consequence of having too much heart! ORDER 7. _Pachydermata (thick-skinned)_. In Greek _pachus_ means thick, and _derma_ skin. _Pachyderms_, therefore, are thick-skinned animals. It is rather a vague denomination, as you perceive, and does not tell us much about them; but it appears that it was not very easy to find a better term. For my own part I should be very much puzzled to find a name really suitable for such an irregular company as this, in which all the huge beasts of the earth--the elephant, the rhinoceros, the hippopotamus--are heaped one upon the other, side by side with the horse, the ass, and the hog; begging your pardon for an ugly word. All these creatures live on vegetables, with the exception of the hog, to whom nothing comes amiss; or who, in other words, is _omnivorous_, like the bear, and also another member of the class _Mammalia_, which I do not name for fear of making you blush at your companionship. This assures you that, in the order of the _Pachydermata_, the digestive apparatus is very fully developed. The horse, for instance, has a very voluminous stomach, which extends much farther back than the point at which the oesophagus empties itself; and in which, on close examination, a sort of contraction is observed which appears to divide it in half, producing the false effect of there being two stomachs. But, after all, we do not find, even in this case, any essential difference to remark upon in the internal arrangements; it is always the teeth we must look at if we want to have something to say. There, indeed, we have only to choose; nature has indulged herself in all manner of fantastic freaks. To begin with the elephant, the grand master of the order, he presents us with one of the most oddly-furnished jaws in existence. Every one knows those two enormous tusks which protrude from his mouth, and which furnish human industry with nearly the whole store of ivory it has need of. Those two teeth are the largest, beyond comparison, of any in the animal kingdom; yet they are two merely ornamental teeth, perfectly useless in the operation of eating, and very ruinous into the bargain to the proprietor. All those stores of the blood which furnish the materials for ivory pass into these tusks, and, as often happens to people who give way to a taste for luxuries, there is nothing left wherewith to provide the animal with serviceable teeth. Those tusks of the elephant are nothing but his upper incisors, the only ones, observe, which curve in coming out of his jaw. In the lower jaw he has no incisors at all; canine teeth are entirely wanting; and by way of dental apparatus, this meagerly-furnished mouth possesses on each side of either jaw one or two molars, enormous in size, but not of ivory. They are composed of a number of enamelled upright layers of tooth-substance (_dentine_), soldered together with a bony cement; and these are our giant's only resource for chewing the grass, young shoots, and leaves of trees, which are his natural food. [Footnote: These teeth are nevertheless very efficient grindstones.] As a consolation, he has the glory of knowing that he possesses the very finest teeth in the world, the terror of all who approach him; and I can compare him to nothing so well as to a vain woman, who is contented to live on potatoes that she may wear fine clothes and excite the envy of her neighbors. The hippopotamus also has incisors in the upper jaw, which curve as they come out of the mouth; but these never attain anything like the size of the elephant's tusks, neither do they hinder the development of the other teeth, of which this animal has a very respectable collection. The upper incisors bend downward; those in the lower jaw stand out horizontally, and terminate in sharp points like plough-shares; and indeed the hippopotamus uses them for tearing up the ground in order to get at the roots which form its nutriment. These are, besides, formidable weapons, with which when enraged the animal can tear even boats in pieces; for, as you are aware, the hippopotamus is almost amphibious, and browses on water-plants, and lives in the great rivers of Africa, its native country. Its name alone would have told you this had you understood Greek; [Footnote: _Ippos_, a horse, and _potamos_, a river. The Greeks, who had seen the hippopotamus in the Nile, in Egypt, named it the river-horse; as afterwards the Romans called the elephant the ox of Lucania, because they first saw it in Lucania during the war with Pyrrhus.] but I have no complaint to make this time, for it was the Greeks themselves who gave it. You would find it very awkward, would you not? if you had to breakfast at the bottom of the Thames, and could not swallow a morsel without having your nose filled with water? But the hippopotamus labors under no such inconvenience. Its nostrils are provided with two little doors, which it closes at will, and behind this screen the lungs keep quite quiet while the animal goes backwards and forwards in the water. There is generally a hippopotamus in every large menagerie. The next time you visit one look at him. You will see him with a large stomach almost trailing on the ground: and no wonder; he needs plenty of room in which to stow away all the canes, reeds, and water-plants from the bottoms of rivers, which are not very nutritious food. Accordingly the stomach of the river-horse presents the appearance not only of two compartments, like that of the true horse, but looks as if it were divided into three or four. To conclude my account of this animal, I must add that the ivory of its teeth is even more beautiful than that of the elephant's tusks, and that dentists carve it into very magnificent teeth for their patients. This is not a matter to interest you much at present, but we never know what may happen. I advise you, however, never to make use of hippopotamus's teeth; they turn yellow very quickly, and, when people are driven to buy teeth, the least they can try for, is to get good-looking ones for their money. I should like to say something about the rhinoceros while we are on the colossal tribes, but it is a very unsatisfactory subject. The animal has no canines, sometimes no incisors even; sometimes it has as many as thirty-six teeth, according to the species, as naturalists aver; and this is all I have to say about this great lump of flesh, so misshapen outside, yet so regularly formed within. He it is who especially deserves the title _pachydermata_, his skin being so hard and thick that bullets glance off its surface. But this has nothing to do with our present subject, any more than the horn upon his nose, whose turn for description may come if I ever give you the history of the skin and all connected with it. The hog also has canines, and very strong ones; but it is in the wild state, when it is called a boar, that these appear in their real form. There we find them projecting out of the mouth with a curve, as is so commonly seen among the _pachydermata_, forming those terrible, sharp, and pointed tusks which have been so often fatal to the hunter. The wild boar of the forest is supposed to be the original ancestor of the domestic pig; and if, as is probable, this is really the case, we have here a remarkable instance of the effect of man's treatment upon the organisation of the animals he collects around him. The wild boar lives only on fruits and roots, which, like the hippopotamus, he tears up with his tusks, those safeguards of his, amid the many perils of his life in the woods. In the service of man, on the contrary, he becomes lazy, cowardly, and greedy; unlearns his energy and combativeness, eats all that is offered to him in the trough, even meat, when it happens to be thrown in; and, in order to do this moreeasily, has recalled toward his mouth those formidable war-tusks of his, so tremendous as weapons, so useless as teeth; has, in fact, turned his sword into a fork. It is the case of a Tartar degenerated into a Chinaman. [Footnote: China, about which we have heard a great deal of late years, has been several times invaded by the warrior hordes of Tartary. But at each time, unto the second and third generations, the vanquishers have taken the effeminate manners, the costume and the usages of the vanquished, and so many conquests have only resulted in converting millions of Tartars into Chinese.] This suggests to me an idea relative to the horse, the last important member of the _pachydermata_ which remains to be spoken of. It also has its canines, but very small ones; they disappear, so to speak, in a large vacancy between the incisors and the molars, where man inserts the bit, by means of which the animal has been subdued. Small as these are, however, these canines indicate that the horse might eat flesh, canine teeth being the distinctive attribute of the carnivorous mammals. I have read somewhere, but I do not remember where, that an unusual development of strength could be produced in the horse by feeding it on flesh; and the old Greek poets write of a king [Footnote: Diomed, King of Thrace] in the barbarous ages who gave his horses, men for food. If I knew some rich professor who was inclined to spend money in the investigation of a curious fact, I would advise him to set apart a sum for putting horses on a meat diet, from sire to son, gradually increasing the quantity; and I would boldly warrant that in the course of successive generations the canines would become so large as to impede the entrance of the bit into the mouth, and, moreover, would make it rather a ticklish office for the groom to place it there. But let us set aside the teeth the horse might possibly have, in order to examine those it has already. There are six incisors in each jaw; these are long and rather projecting teeth, by examining which, the age of the horse can be detected from certain marks which appear in them from year to year. The molars are flat, square, furrowed with bars of enamel, marking out more or less distinct crescents; perfectly constructed, in short, for chewing hay and oats. Nevertheless, I should never be surprised to see the enamel crescents become sharp-cutting in our rich professor's stable; so skillful is the unseen Architect who created animals, in altering the house when the tenant changes his habits. ORDER 8. _Ruminantia (ruminants)._ I shall retain through life a pleasant recollection of the _ruminants_. Through them I obtained the first prize for natural history which was ever given in France to the pupils of the learned university. It is thirty years ago since this happened, and I own, without any false modesty, that even now the word _ruminant_ rings very agreeably in my ear. It reminds me of one of the proudest moments of my life, of the honor done to me by the illustrious Geoffroy St. Hilaire, when he called me, a little college urchin, up to him, that he might have a nearer view, as he said, of the baby-professor who had spoken so well on ruminants. Yes, it is more than thirty years ago, for alas! it was in 1831. There needed no less an event, as I have told you before, than the revolution of 1830 in France to induce the big-wigs of education to sacrifice two hours per week in one class to the study of natural history. Yes, my dear child, it is only that short time ago since natural history became one of the subjects of study in French colleges; and the gray-haired men of the present day finished their education, as it is called, without having learnt a single word of what I am now taking the trouble to teach you, a mere child. You see you have come into the world just at the right time, and will be able to instruct others in your turn. But before giving lessons to other people you must first finish learning your own. Forgive me this involuntary reference to a happy time when I was not much more rational than you are. And now, let us return to our ruminants--those dear, good beasts, the nourishing fathers of the human race. LETTER XXXII. MAMMALIA--_continued_. ORDER 8. _Ruminants--continued_. Every created thing has an appointed part to perform; but there are some mysterious parts of which we cannot understand the drift. That of the ruminants, however, is so clearly marked out, that we detect it at a glance. To qualify myself for supplying your young mind with the food I am going to offer it to-day, I have been obliged, my dear child, to browse in a good many books of which you could have understood but little yourself; and I have been forced to ruminate a long time upon what I have read, and to digest it slowly in my head, which I may say, without vanity, is of larger capacity than yours; no great wonder at my age. Now, if I have succeeded in my undertaking, you will benefit by all the work which has been going on in my mind for the purpose of feeding yours without over-fatigue to it; and I shall almost have the right to say that its nourishment has been derived from me. My lamp could tell you what it has sometimes cost me to supply a single page which might instruct, without repelling you. Now, this is precisely what the _ruminant_ does. The part he has to perform is to collect in the meadows a sort of food, which would disgust less well-organized stomachs than his own, to work it well up within him, and to give it back in a more palatable and less indigestible form. The little flesh-eaters (_carnivora_) come afterwards to the feast, and the feast is himself! The whole history, then, of the ruminant is to be read in his stomach. His real office is to digest, and in fact he devotes the best hours of his days to the perfecting of that beneficent labor, on which the life of so many weak stomachs depends. Have you ever amused yourself by watching a large ox lying down in a meadow? Long after he has finished grazing, his jaw continues to work, turning round and round like the grindstone of a painter when he is rubbing down his colors. Look, and you will see that he will remain there for hours together, motionless and contemplative, absorbed in this incomprehensible mastication, rolling about in his throat from time to time some invisible food. Do not laugh at him, however. As you sec him there he is performing his part in life, he is _ruminating_. To ruminate is to chew over again what has been already swallowed; and, however droll this may seem to you, it is the business which all ruminants are born to. You remember the monkey's pouch, which serves him as a larder, whence he takes out his provisions as he wants to eat. The ruminant has an immense pouch of the same kind, into which, while he is grazing, he hastily conveys large masses of half-bitten grass. You probably think he is eating when he has his head down in the grass; but you are mistaken. This is only a preparatory work; he is hastily heaping up in his larder the food he intends to eat by-and-by; only his larder, instead of being, like the monkey's, in his cheeks, where, indeed, there would not have been half room enough for those great bundles he tucks in, is in the middle of his body, close to the extremity of the oesophagus, whose lower wall, being slit at that part, becomes an imperfectly secure tube, ready to burst open under pressure, and allow the food to escape between the edges of the slit; these, otherwise, remaining naturally closed. As soon as the large bundles of grass come to this part, they press against the walls of the tube, which they by this means separate, and fall into the provision-pouch, which bears the name of paunch, or grass-pocket, in fact. As soon as the paunch is well filled, and the animal sure of his dinner, he lies down in some quiet corner, where he proceeds gravely with the important act, which is the real object of his existence. A little below the entrance to the paunch, and communicating both with it and the canal of the oesophagus, is a second receptacle, which old French naturalists, not being much acquainted with Greek, named the _cap_, on account of its fancied resemblance to the caps worn on the head, and which we call 'king's hood' or 'honey-comb bag.' This second stomach now contracts (at least so it is supposed), and thus retains, as if with a closed fist, a portion of the grass accumulated in the paunch: of this it forms a pellet, which it sends back into the oesophagus, and the oesophagus, by continued contractions from below upwards, returns it to the mouth, where at last the grassy lump is chewed in good earnest, and to some purpose. There is no necessity for hurry; the ruminant has no other business on the face of the earth but this, and thus hour after hour passes away, the food pellets rising one after another to the onslaught of the teeth. Nor do they go back again until they have been reduced by long mastication into an almost liquid paste, which glides through the oesophagus without forcing open the slit, and falls straight into a third pouch, called by old Frenchmen the _leaf_, on account of certain large folds, some what like the leaves of a book, which line the interior; and known to us as the _manyplies_. From this stomach, No. 3, this grass-pap passes into a fourth and last bag, which is the real stomach, and where the final work of digestion is accomplished. This fourth pouch also has a pretty little name of the old-fashioned sort, like the three others; it is called the _reed_ or _rennet-bag_, from the property it possesses, in the calf, of turning milk into curds: and of his four stomachs this is the only one which the ruminant makes use of at first. As long as the young animal is nursed by its mother, the other compartments remain inactive and small in size; they neither grow nor exercise their functions until it begins to eat grass. Indeed, they would probably entirely disappear, if any one would go to the expense of keeping the animal on milk all its life. If it ceased to have anything to ruminate, nature would certainly lose no time in relieving it of its useless workshop of rumination. As it is right to give every one his due, I will mention that we owe our accurate knowledge of this simple and ingenious mechanism of _rumination_ to the labors of Flourens, a scientific Frenchman, who is still alive, and who has made a great many interesting inquiries into the subject we are now considering, _i. e._, the life of animals. He is a very clever man into the bargain--so perfect a master of his own language, that the French Academy has felt itself justified in opening its doors to him--an unheard-of honor for a member of the Academy of Sciences. And yet, in spite of all this, I heartily congratulate you that the discovery of the _paunch_, the _cap_, the _leaf_, and the _rennet-bag_, was not delayed for his arrival. He is just the man who might have been tempted, in his capacity of profound scholar, to have hunted up for them in the _Jardin des racines grecques_ [Footnote: Your brother can tell you about the _Jardin des racines grecques_. It is a charming little book, of which every generation of collegians has learnt, by heart, the commencement; but I have never known one, even among the most intrepid, who had ever been to the end of it.], four magnificent names, which would only have bewildered you. Beyond the rennet-bag there is no change of conformation to note, except that the intestinal tube is naturally much longer than ours, on account of the difference of food: as a general rule, it is ten or twelve times the length of the body. The sheep, who is able to pick up a living in the poorest pastures, is indebted for this inestimable power, which makes him the special blessing of dry and barren countries, to a still further peculiarity of organization; with him the intestinal tube is twenty-eight times the length of the body. We have seen among the _Carnivora_, whose jaws have so much work to do, that the condyles of the jawbone are sunk deeply into the fossa of the temporal bone. The ruminant, whose peaceful mouth is formed for contending only with grass, is organized quite differently. Here the condyle is flattened, and the fossa of the temporal bone very shallow, presenting to the condyle an almost flat surface, so that the jawbone is enabled to revolve with ease for the better mastication of the pellets of grass. This conformation is also to be seen in the _pachydermata_ who feed upon vegetables. In the horse, especially, whose food is almost the same as that of the ox, the _articulation_ (as this joining of the condyle to the temporal bone is called) of the jaw, is also nearly identical; and it is the same with the teeth, with very trifling variations, those of all ruminants are constructed on the same plan as in the horse. The canines only require a separate notice. But first I must tell you that, by some special privilege, the reason for which I do not undertake to explain, the order of ruminants is the only one containing animals with horns on their foreheads. Stags, goats, reindeer, chamois, gazelles, roebucks, oxen, buffaloes, all the beasts with horned foreheads, belong to the ruminants. Indeed, this fact would form a very convenient mark of distinction between them and other animals, were there not exceptions to it. Some ruminants have no horns; and then, as if in compensation for the deficiency, we find them provided with canines in the upper jaw, in addition to those below. The ruminant which has the most beautiful canines is the musk-deer, a pretty little animal inhabiting the highlands of Central Asia, like the chamois of the Alps. But now that you know who he is, you will probably often be tempted to wish he had never existed; for it is from a small pouch below his belly that people obtain that odious musk of which Oriental beauties are so fond, and which even certain strong-nerved ladies of our own country are guilty of using in public, to the great detriment of general health. But enough of this; our business is with the canines of the musk-deer. They project with a descending curve from the upper jaw, and would give the animal the very false appearance of a small wild boar, but for the great delicacy of its legs, which are more slender than even those of our roebuck, to whom, with the exception of the horns, it bears a close resemblance, as its name implies. After the musk-deer comes the large family of camels and llamas, which represent--the former in Asia and Africa, the latter in America--the irregular groups of ruminants which have canines instead of horns, and which seem to be placed as intermediates between true ruminants and the pachydermata. They form the connecting link between the horse and the ox, and men prefer employing them as beasts of burden to using them as butcher's meat; though one could eat them in their own country with less disgust than Europeans feel in making a meal of horseflesh; so that they might be a very acceptable resource in many cases. The real fact is, that ruminants with horns and without upper canines have more delicate flesh than the others, and seem more especially destined to be eaten. Yet if one had only to look at the stomach, which is, after all, the distinctive characteristic of the order, camels and llamas would stand in the first rank as ruminants. Besides the usual character of four stomachs, their paunch and honeycomb-bag are furnished with large cells which act as reservoirs, and fill with water whenever the animal has the chance of drinking freely, and from whence in time of drought he draws it up into his mouth and swallows it. This is what makes the camel so valuable to the wandering tribes in the great deserts of Africa and Asia. He is the only animal who can pass several days under the burning sun of Sahara without drinking--or rather without appearing to do so--for he carries his provision of water concealed from all eyes in the recesses of his body. I dare say you have often heard stories of Arabs dying of thirst who have opened the stomachs of their camels in search of a last draught of water. It must be a terrible thirst to drive a man to such an extremity; for, as you may imagine, one could not expect the water there to be either fresh or clear, to say nothing of the great risk there would generally be of finding the reservoir empty. Such an extreme is never resorted to till water has failed for a long time, and all the goatskin bottles have been emptied; and in such a ease it is but too likely that the camel has followed his master's example, and emptied his water-skins for his own use. But this is only half the internal fittings of the "ship of the desert," as the Arabs call him. In the desert it is often as difficult to find food as water; and nature has equally provided for this. The hump you see rising upon the camel's back in your picture-books is his safeguard against starvation. It is a huge mass of fat. I need say no more. You will remember Mr. Liebeg's pig, which lived 160 days upon its own bacon. Without going quite such lengths as that, the camel can keep up his fire for a long time upon the fuel which the blood obtains from this blessed hump. Since we are talking of this animal, and he takes a remarkable place in a history of nutrition, I ought to tell you that camels are classed into two families by their hump: there is the camel, properly so called, which has two humps, and the dromedary, which has but one. This latter did not require such a supply of provisions as the other, for he is very much swifter of foot, and consequently his journeys are more speedily performed. I have nothing particular to say to you about the other ruminants, in the matter of their organs of nutrition; but I will not quit the subject without reminding you of one thing which concerns nutrition, not theirs, however, but ours. It was by the taming of the domestic ruminants--that unfailing dinner-material which now follows everywhere at the heels of his master--that human civilisation began. Before that event, man, driven to depend for his living upon the hazards of the chase, spent his whole time in seeking for food, and had none to spare for the pursuit of any other branch of industry. Far as we may ascend in the history of ages we shall find shepherd races. Beyond them there is no history at all, nor could there be. The first leisure hours of man, and, consequently, his first efforts in art and literature, date from the period when the ruminant animals, those special fabricators of nutritive aliments, were gathered around mankind, and worked out their destiny under the shadow of his tent, by his direction, and for his benefit. But all this is so distant from us now, that it is scarcely worth the trouble of thinking about. The human race is somewhat like those old people who have lost all recollection of their childhood; and young people are not required to know what their elders have forgotten. It is well, however, that they should not be quite ignorant on the subject. When you hear that the Society for the Prevention of Cruelty to Animals has taken up the cause of some barbarously-used ox or sheep, do not turn it into ridicule. Those humble species have supported ours from the first; and you should recollect, now and then, that human society made its first step forward when it began to keep flocks and herds. LETTER XXXIII. MAMMALIA--_continued_. We come now to animals less familiar to you, and none of which inhabit Europe. We shall therefore pass more quickly over them. ORDER 9. _Marsupialia (pouched)_. _Marsupium_ is Latin for purse, pouch, or pocket. The marsupials are distinguished from other animals by a pouch which the mother has under her belly, and in which the little ones take refuge at the slightest alarm. You would be very much interested with their whole story; but it has nothing to do with our present subject, which we should soon lose sight of if we once began to wander away. This order, so easily distinguished otherwise by that singular pouch, unfortunately for us, offers nothing new for observation. It includes several species, differing entirely from one another on the subject of nutrition, and closely resembling some already described. Some are both carnivorous and insectivorous, and are therefore armed with powerful canines, and with molars like those of the hedgehog. Others are herbivorous, like hares, and have almost the jaws of a rodent. Among the former we have the opossum, celebrated by Florian in one of his prettiest fables. The opossum inhabits South America. Charming little marsupials are to be found in the Molucca Isles, whence come the nutmeg and the clove; these are very like our squirrels, and live as they do, in trees, hunting after fruit and insects. But the greatest number of marsupials belong to Australia, the real native land of the order. They form by far the larger portion of the mammalia with which that country is enriched; the most celebrated amongst them being the kangaroo; an animal which is now becoming common in European menageries, and which, excepting in the matter of its pouch, is nothing but a magnified rabbit, as tall as a man, and with a tail almost as long as itself. As a rabbit, you know what its eating apparatus must be; and some day, no doubt, the French Acclimatisation Society will enable us to judge of its flavor. It is a kind of meat very likely to be seen on our dinner-tables by-and-by; and, as you have plenty of time before you, probably you may eat of it before you die. ORDER 10. _Edentata (toothless)_. These come more directly within our limits. They are classed according to their teeth; yet if their name were to be trusted, they ought to have no teeth at all. Whereas, alas! almost all of them have some, and I am heartily ashamed of their scientific designation; but how can we help it? The only really _Edentata, i. e_. toothless animals, amongst them are the ant-eaters, who, considering the nature of their food, are not much in want of teeth. They feed among the ant-hills, whence they get their name; and as they are a tolerable size (from two to three feet in length), it would really have been quite a hardship upon them to have been forced to crunch the ants one by one at every meal. To get on rapidly they catch them with their tongue; but what a tongue! Imagine a kind of long earthworm, lodged in a snout which is elongated like a bird's beak, and has a very small opening at the extremity. The ant eater inserts this long, string-like tongue into the crowded ranks of its victims, and, as its surface is glutinous, they stick to it by hundreds at a time, and are swallowed at one gulp without a chance of escape. This tongue, perfectly unique in its character, stretches out in its murderous exertions to nearly three times the length of the animal's long head. What a distance there seems between such a tongue as this and your own little doorkeeper! But no wonder: we have now reached the confines of the kingdom of _Mammalia,_ and the face of nature is beginning to change. The Armadillo, for instance, which comes next to the ant-eater, looks far more like the tortoise or lizard than its noble mammalian brethren. It is covered with scales; and, to look at it, you would say it was a reptile, in spite of its higher internal organization. As for teeth, it has certainly enough of them to give the lie to its name of _edentata;_ but they are not very serviceable ones. They are called molars, however, because they are situated in that part of the mouth which is always assigned to molars; but they are miserable grindstones, very unlike any of which we have hitherto treated. They are all of them flattened cylinders, with no enamel bars to strengthen them; are small and poor, and are placed at rather wide intervals from one another. The poor armadillo munches with these, as best he can, slugs, tender roots, and other prey of the same sort, with which he is obliged to content himself, and which do not require very formidable tools. The most questionable member of this class is the Unau, or Two-toed Sloth. It only wants incisors to be as toothless as ourselves! and the first time I saw it I took it for a little bear. It is true I was then younger than you are now; for the bear, who is one of our nearest neighbors, ought not to have been confounded with the unhappy being before us, one of the drudges of the animal creation; though M. de Blainville (who had not my excuse) proposed placing it still nearer to us, namely, amongst the _Quadrumana_. Observe that instead of hands it has at the end of its fore-limbs only two enormously curved claws, which have somewhat the appearance of a gigantic fork accidentally twisted. Accordingly its illustrious sponsor offered it to the world as an _irregular quadrumane_. I believe so, indeed! This _quadrumane_ without hands--this _edentate_ whose molars are preceded by magnificent canines--this enigma of nature, created for the confusion and despair of all classification--does, I must in all humility confess, completely upset the rule I laid down so stringently when speaking of the horse, as to the objects for which canine teeth were framed. The canine teeth of the sloth are more developed than its molars, and yet I cannot tell you what they are there for at all. It feeds upon the leaves of trees; and old travellers in South America, where it inhabits, have told us that, when it has once hoisted itself up a tree, it will strip it to its last leaf, and afterwards drop to the ground to avoid the trouble of crawling down. This was what first obtained for it the villanous name of sloth, a title which is certainly justified by its gait when on the ground; for it is so ill-made that it cannot stand upright on its legs, but moves clumsily forward by dragging itself on its elbows. It seems, however, that when once in a tree it is a different creature altogether, and can scramble lightly from branch to branch. Moreover, if its claws cannot reasonably be reckoned as hands, they are at all events excellent hooks; and when it is springing about thus in the forest, suspended to the branches by its long arms, one might be tempted, while watching it from below, to decide in favor of M. de Blainville's opinion. I saw it originally myself in a cage. As to the sloth's relationship to the armadillo, this rests upon a detail which bears directly upon our subject. The molars in both animals are cylindrical and smooth, this is a trifle, but what would you have? The animal had to be classed somehow; since naturalists have not had the wit to make detached companies, as they do in regiments of soldiers. ORDER 11. _Amphibia (two-lived)_. We are going farther and farther away. Here are animals who are nearly half fishes (_amphis_, _double_, and _bios_,_life_). The _Amphibia_ have two lives: one in the water, which is their true life, and where they are in their element; the other upon land, where they can only crawl; for their paws, which are but half developed, are destined to perform the office of fins, and the hinder ones are extended flatly behind them, and act like a fish's tail. They are divided into two families, the seal and the walrus. The first feed on fish, and have the same internal organization as the _Carnivora_, as well as the same dental conformation. Some species have even exactly thirty-two teeth, as we have. The jaw of the walrus is the least regular, and the incisors are generally wanting, especially in the full-grown animal; for it appears they lose them very young, as you lost your milk teeth, only, unluckily for the walrus, his never grow again. On the other hand, he has two canines in his upper jaw, which, next to the elephant's tusks, are the largest we have yet met with. They are sometimes as much as two feet long, and incline downwards with a curve, like the two bars of a pick-axe. They would play the walrus the same trick that the incisors of rodents are apt to do when they have not work enough to wear them down; that is, stop up the entrance of its mouth, were it not that the lower jaw is contracted in front, in order to fit into the space between the two canines, which thus form a sort of passage in which it manoeuvres freely. As you may suppose, the walrus cannot insert prey of any great size into this contracted passage; but that is no matter, as he lives partly on seaweeds, and partly--indeed principally--on shell-fish; his molars being specially adapted for breaking shells. They are short massive cylinders--the upper ones fitting into the lower as a pestle into a mortar. After the walrus comes a strange animal which has been ranked among Cetaceans (we shall see why presently), but which it would be better not to separate from the Amphibians, since an Amphibian order has been made, for it crawls from time to time upon land: this is the Manatee, or Sea-cow. It comes still nearer a fish than the others. Its forelimbs are absolute fins, with mere vestiges of nails at their edges; it has no hind ones, and its body, which is quite cylindrical, ends in a fin tail in the shape of a shovel. The sea-cow feeds on plants and herbage, and lives at the mouths of great rivers, going up them occasionally to great distances, their banks serving it for pasture ground. In some respects it is half brother to the hippopotamus and the great grass eating _Pachydermata_, to whom it comes so near in internal organization, and above all in the structure of its molars, that M. de Blainville seriously proposed ranking it among the elephants, though as an _irregular elephant_, as you may suppose. But then Cuvier had even placed the seal among the _Carnivora_, by the side of the cat, whose whiskers it possessed, and of the dog, whom it resembled in the formation of its head. A naturalist's office is sometimes very perplexing, I assure you; and as we are touching on this subject, I cannot resist telling you that the sea-cow laid claim to, on so many sides, had by right a free admission to the celebrated order of _Primates_, although it looks exactly like a large barrel elongated at the two ends. It suckles its young at the breast like man and the monkey; and if Linnæus flinched from this rather too absurd parentage, old navigators were less scrupulous. Observing this creature in the distance, sporting on the waves, the upper part of its body quite out of the sea, the sailors, whose eye is not of the most refined, and who have no objections generally to the marvellous, imagined they saw a new species of human beings; and hence arose those stories of mermaids and sirens which have been told from the days of Homer downwards, and the traditions of which have not yet quite died out in seaport towns. To have been passed from man to the whale, touching the elephant on the road, is a long way to travel, especially when, after all, one is only a huge barrel of amphibious fat; and you may judge from this that it is not always an easy thing to classify animals. ORDER 12. _Cetacea (whale-kind)_. Cetaceans are whales; and if I had been consulted on the matter, I should have joined this order and the last together, under whatever name was thought most appropriate. The passage from the seal to the whale through the walrus and the sea-cow is an easy and natural one, the two latter being obviously the connecting links; and in spite of certain diversities of food, they form in reality one family-party, as do the marsupials. But it is too late in the day to talk of this, my dear child, and you and I cannot pretend to alter what is taught in the schools. But you are astonished, are you not? to hear that the whale is not a fish: and no wonder. It is with it, however, as with the armadillo; it is a fish with a higher organisation inside. The interior of this enormous mass is a faithful reproduction, as a whole, of that of the shrew-mouse; and when we come to talk of fishes you will have some faint idea of the prodigious distance which this places between the whale and his countrymen of the ocean. As far as we are concerned, the chief difference is in their way of breathing. The cetaceans breathe like ourselves, and are obliged to come to the surface of the water to take air; while fishes have a special apparatus, which I will explain to you presently, which enables them to breathe in the water. This is a disadvantage to the cetacean in his fish life; nevertheless, of all the mammals (as may easily be imagined) he is the one who can remain longest under the water. With us, for instance, the best divers one ever heard of, those who go to the bottom of the sea after the pearl-oyster, can scarcely stay below longer than two minutes; and even during that short time the veins of the head become so overcharged with the blood, which cannot return to the lungs owing to its forced inactivity, that when the diver comes back to the surface it is by no means unusual to see him streaming with blood from both nose and ears. The cetaceans remain under water for half an hour at a time without seeming to suffer in the least; and Breschet, a clever French naturalist, has given a very satisfactory explanation of this wonderful faculty. In dissecting a cetacean, he discovered all along the vertebral column an extensive network of large veins, which are not found in other mammals, and which seemed designed to serve as a refuge place for the blood during the time the animal remains submerged. According to him, this network would act as a reservoir, to which any overplus in the head or important organs would flow through vessels communicating therewith, and which might swell out as it pleased, without any risk to the inert bed of fat against which it lies. From thence the blood rushes to the lungs, as soon as the animal's return to the air enables them to play as usual. It must be admitted, at the same time, that all this involves the necessity of a much less active life than that of land mammals, that is to say, a consumption of oxygen much smaller in proportion than theirs; for were you to be furnished down your back with the finest network reservoir in the world for venous blood, it would still not enable you to remain half an hour without breathing. There is nothing remarkable in the digestive apparatus of the cetaceans except about the mouth, which is, as you know, the essentially variable point among animals. To begin with, the cetacean tongue has the most original appearance possible. Indeed, it is not a tongue, but a large carpet, spread over the floor of the animal's mouth, and bears not the faintest trace of resemblance to that nimble delicate porter, who does you such good service. Imagine a thick soft lump absolutely crammed with fat, and completely immovable, because it is glued down along its whole length to the bottom of the mouth, and you will have a good idea of this strange tongue, which in the whale, the largest of the cetaceans, attains to the length of twenty-five feet and the width of twelve, and of itself alone furnishes the whale-fishers with from five to six tons of oil. This is a great deal farther from us than even the long string which serves as a tongue to the ant-eater; and you feel at once that we are getting among strangers. With respect to teeth, I have now a melancholy piece of news to tell you. We have done with them; we have seen the last of incisors, canines, and molars, henceforth you will hear no more about those valuable instruments. The teeth of the cetaceans, with whom this painful falling-off begins, are no more teeth than his tongue is a tongue. They are like so many nails set in a row in the jaw, and can only be of use in retaining prey, not in grinding it; so that of the many processes your bit of bread has to go through before it becomes a part of yourself, there is one which is dispensed with here altogether, namely, mastication. Cetaceans swallow their food without chewing it. Besides, they have not got a whole set even of these unmasticating teeth. Dolphins and porpoises, those faithful companions of the sailor, around whose vessel they come playing and tumbling in the seas of all countries, are the only ones who have them in both jaws. And these are the small fry of the order; they do not usually exceed six or ten feet in length. The Cachalot, or Spermaceti Whale, an enormous cetacean, which rivals the true whale in size, and whose head alone forms nearly the half of its body, has teeth in the lower jaw only. This lower jaw, whose two sides are joined together for half their length (a new deviation, very unlike anything we have found before), is so little proportioned to the gigantic head which contains it, that it is almost lost to sight, and seems like a small plank slipped under a great square block. Such as it is, however, it possesses many very respectable teeth, of which some weigh as much as two pounds; and with these the cachalot, whose ferocity is tremendous, tears in pieces everything that comes near it, sometimes even the boats of the fishermen who risk their lives in the dangerous pursuit of capturing them. By a singular arrangement, of which this is the only known instance, there is, opposite each of the cachalot's teeth, a corresponding cavity in the upper jaw, into which they fit closely, turning the monster's muzzle into the most formidable pair of pincers to be found in the animal kingdom. Another curiosity in the order is the tooth of the Narwhal, a modest cetacean, who is not much more than twenty feet long! I speak of _the tooth_, because the creature has commonly but one; a cylindrical-pointed tooth, spirally furrowed, whose length varies from six to ten feet, and which comes straight out from the extreme front of the upper jaw, like a soldier's pike. There are two sockets at this extremity of the jaw, each furnished with a tooth-germ; but as a general rule the germ on the left side is the only one which develops, the other lying asleep in its socket, where it is choked up and never appears. Behind this long pike, which, like the tusk of the elephant, attracts to itself all the ivory in the body, lies a completely unfurnished mouth; so that the owner of this magnificent weapon, invaluable as a war-tool, but quite inapplicable to the purpose of supporting life, is obliged to feed on small fishes and _mollusks_. We have not yet spoken about these latter, but if you have ever seen slugs and snails you will know what a _mollusk_ is. The same wretched food falls to the lot of the whale also, that giant of the ocean, whose open mouth forms an aperture twenty feet in extent. Geoffroy St. Hilaire, in his indefatigable endeavors to trace out points of resemblance connecting together animals the most unlike in outward appearance, discovered, along the lower jaw of a young whale, certain traces of teeth, indicating a last effort on the part of nature to carry out her usual plan in furnishing the jaws of mammals; but, like the right-hand tooth of the narwhal, these vain attempts soon disappear, overgrown and lost in the tissue of the bone, so that the whale offers us a true type of an _edentate_, classable with the ant-eater, if one dared, and some people have dared, which by this time will not surprise you. A classifying professor is utterly merciless, whether he gets hold of the poor beasts by the mouth or by the paw: they may protest with all the rest of their body against the peg on which they are hung; so much the worse for them! If one were to listen to what they have all got to say, it would be impossible to classify even one. To return to the whale. As a compensation for the teeth which she found herself unable to give him, nature has manufactured on the two sides of his upper jaw the most extraordinary apparatus without exception to be found in the mammal mouth. You know what is called the _whalebone_ used in stay-making, &c. The name is quite correct; for those little flexible black strips, which support the figure so nicely, began life in wandering over the polar or Australasian seas, fastened to the palate of some monstrous whale. On the two sides of the upper jaw the membrane which covers the palate sends out rows of broad, thin, horny plates, which are from eight to ten feet long (they have sometimes been seen twenty-five feet) in the centre of each side, but which decrease gradually towards the extremities. These are plates of whalebone (sometimes called whale's whiskers), and the industry of man has turned them to a thousand different uses; and you will open your eyes in astonishment when I tell you that 800 or 900 of them have been sometimes counted on each side of one mouth. Think of the number of stays that could be furnished from the whalebone plates of one whale! It is true, they were not exactly designed for this purpose originally. At the tips and on the edges of these plates, the elastic fibres of which they are composed unravel and peel off, and hang down from the lip like tufts of horsehair. The Arctic seas, which the whale inhabits, are, like other seas, full of innumerable troops of various little sea-animals, and it is these which are destined to the honor of nourishing this gigantic mass of flesh. When the colossus wishes to take a meal, he stretches his mouth to its utmost width, and the salt water rushing in as into a gulf, carries with it the imprudent little fry, who disappear then and there for ever, being retained by the fringe-like sieve of the whalebone. But as, in this way of eating, the stomach of the whale, however large, would be terribly overgorged with water, he is furnished with another apparatus for preventing the inconvenience. All the superfluous water is rejected by the _pharynx_, and springs up in spouts of fifteen or twenty feet high, through the nostrils, _i.e._ the nasal openings, sometimes called "vents," sometimes "blow-holes," which are pierced exactly at the top of the head. This is a peculiarity common to all cetaceans, who have thence received the name of "blowers," alluding to the powerful blast which is necessary to send those majestic columns of water into the air; but it takes a much milder form with the lesser cetaceans, such as dolphins and porpoises. There is but a slight jet with them: the water escapes comparatively quite quietly from the nostril-vents, trickling away down the animal's sides. I hope you consider that I have told you something new this time, my dear child, and that our machine is beginning to change its appearance very materially. I told you before that we had reached the outskirts of the mammal kingdom. When we got to the armadillo we were within a stone's throw of the reptiles, and here, one step more would take us to the fishes. But we must first consider the birds, who are a very superior set of animals to either of the latter; and we have accordingly an order of mammals (Monotremes) which, as you will now find, opens the road on that side also. There are but two sorts, and both of them are natives of Australia, which is, as you may have heard, the land of the wonderful in natural history, and their existence was unknown to the learned men of Europe till within the last sixty years. The most extraordinary of the two is the _Ornithorhynchus_, or, to translate the hard Greek word into English, the _Duck-bill_. Its mouth is a true duck's bill, a downright horny beak, and its short paws sprawling sideways with a membrane joining the toes together below, and coming a good deal beyond them in front, seem intermediate between the flippers of the seal and the webbed feet of a water-bird. The first naturalist who had anything to do with the ornithorhynchus, Blumenbach the German, who gave it its pretty name, did not think it was able to suckle its young, so much did it differ from mammals in some respects, though looking so like them on the whole. And presently a report arose in the learned world that the new animal which had been classed at all risks among mammals (it having the close fur and almost the body of the otter), a report arose, I say, that this ornithorhynchus of Blumenbach laid eggs like a real duck. The uproar in the Academies was tremendous. As early as 1829, indeed, a learned Englishman, Sir Everard Home had sent over to France an authenticated drawing, as he said, of an ornithorhynchian egg, to the delight of the hunters after analogies among animal races; while Cuvier looked sadly askance at the intruder, whose arrival threw his animal outlines into confusion, there being no place in them for such a beast. Happily for the poor animal, he has ended by almost settling the matter for himself. The ornithorhynchian egg has never turned up. But in the animal's nest have been found baby ornithorhynchuses, newly born, under two inches long (the full-grown animal being more than a foot and a half), and not a trace of eggshells near. Further investigations showed that the mother ornithorhynchus nursed her young with milk, for curdled milk was found in their stomachs; so the Australian phenomenon has been restored triumphantly to the Mammalian order, whence Geoffroy St. Hilaire had excluded both it and its companion, the _echidna_, a sort of hedgehog, provided like the ornithorhynchus with a bird-like bill, only more of the canary-bird sort; and like it, also, approximating to the bird tribe by other details which do not belong to our subject. And so the matter stands at present; and all we venture to say is that classification had a very lucky escape. And now, my dear child, that I have made you acquainted in detail with your nearest neighbors, the last of whom, nevertheless, are strangely unlike you outside, however they may resemble you within, I shall take the liberty of going more quickly over the ground, and shall point out in the mass only the more important changes which lead from one class of animals to another. I should be found fault with if I tried to make you too learned, and you yourself might be tempted to tell me, to my sorrow, that you had heard about enough. LETTER XXXIV. AVES. (_Birds._) Tell me, my dear child, when you have seen birds taking their flight into the air, and going boldly to their object, without a thought of all the barriers, ditches, rivers, and mountains, which hinder man at every step in his travels, did it never strike you to wish for their wings, and imagine how you would fly off if you had them? If you ever dreamt this dream, do not apologise for it; it is one as old as the world. 'Oh that I had wings like a dove!' cried the Prophet, nearly 3,000 years ago; and the dialogue of the swallow and the prisoner, so often sung by poets, has been repeated in prose behind all the prison-bars on the globe since prisons were first invented. Now you will not think it kind on my part, but I must undeceive you about this fancy, as you will be undeceived some day about many others. The wings of a dove or swallow would be of no use to you if you had them, any more than the formidable swords of the middle ages would be to our modern gentlemen, were any one to put such into their hands. We are not adapted for them, nor they for us. You saw, some time ago, what an amount of muscular exertion was required for running--what a violent flow of blood, what hurried play of the lungs. Now in flying it is still worse; for the earth, at any rate, holds us up quite naturally, whereas the air will not hold up the bird unless it is beaten vigorously and unremittingly by an untiring wing. If we men, constructed as we are, had to do such work, we should be out of breath at once; the heart would cry out immediately for quarter, and the diaphragm turn red with anger. And only just imagine in what a critical position a poor wretch launched into the air on the wings of a swallow would find himself when, at the end of five minutes, his servants should refuse point-blank to go on working at a height of 500 feet above the ground! But a bird has not these internal rebellions to fear. In the first place, it has no diaphragm; so here is another friend to whom we must say good-bye. We shall not meet with him again anywhere. The journey we are taking together, my dear, is somewhat like the journey of life. One sets off, surrounded by friends and acquaintances, but whoever travels on to the end is apt to find himself alone at last; this is what is happening to the digestive tube, which we shall see losing all its accessories, one by one, as we gradually advance in our study. Even now here is one essential fundamental difference in the internal machinery. The body has only one compartment instead of two; and the lungs, masters of the whole space, extend freely to its utmost depths. When a fowl is cut up at table, look along the body, and you will find lodged in the cavity of the ribs, a long, blackish, and spongy mass: this is the lungs. There is not, therefore, the same danger of a bird's getting out of breath as with us; that delicate board which is found in our bellows is wanting in his. His is set in action solely by the to-and-fro movement of the ribs, which is produced by muscular exertions, which are greatly increased during the action of the wings. From which it follows, that the rapidity of flight itself regulates the arrival of air, and consequently the expenditure of strength, or, if you like better, the activity of the fire, since the energy of the muscles depends, as we have seen, upon the quantity of oxygen that feeds the internal stove. This is not all. These elongated lungs are still not sufficient to furnish the blood with all the oxygen demanded by this excessive labor of flight. They are pierced with holes, through which issue pipes which carry the air all over the body. You know what is said of spendthrifts?-that they burn the candle at both ends. It is so with the blood of birds. That fillip which in our case it receives in the lungs, and which sends it back full of vigor into the arteries, is repeated in the bird at the other end of the arteries as well. The capillaries, those delicate vessels at the end of the arteries, plunge from all sides into little reservoirs of air-lungs, therefore-where the blood renews its provision of oxygen, and relights its half-extinguished fire, so that it sends the combustion afresh into the muscles on its return back to the heart, and sets them going a second time. The natural consequence of this prodigality of combustion is, that there must be, in proportion, much more oxygen in birds than in us; and that of all animals a bird is the one most quickly poisoned by his own carbonic acid when the air is not renewed around him. Therefore, let me beg you never to think of putting a poor little bird under a wine-glass, as a child of my acquaintance once did, that she might examine her little friend more closely. In the twinkling of an eye he would consume all the oxygen inside his prison, and you would soon see him fall upon his side and die. On the other hand, the temperature of these flying machines, which consume so much oxygen, is very much higher than ours. It rises to 41°, 42° (centigrade), and sometimes to 44°, 7° higher than with us. If ever you have taken hold of a little bird, you will have remarked how warm it makes your hand: this is quite natural, since there is always a double fire going on within him, to meet the extraordinary expenditure of strength that is required of him whenever he takes wing. Besides, do but look at the poor little creature when you have imprisoned it in a cage! How it goes up! How it comes down! How it hops from one perch to another, with a quick sudden movement, like that of a spring when it unbends. There is no apparent cause for this state of continual agitation; and yet there is a cause, and only too serious a one. Its fire is not slackened because you have put it into a cage, and its muscles, lashed furiously on by the double-oxygenized blood, drive it hap-hazard into a thousand movements, in which it expends, as best it can, a superabundance of power, which no longer finds natural employment. Little children, who are the real singing-birds of our homes, and whose blood also drives much more energetically along than ours--little children I say--often fare no better than caged birds in those larger cages we call schools; and schoolmasters and governesses would scold rather less if they thought rather more about this. It is right, I do not deny it, that the rebellious young rogues should be taught in good time not to abandon themselves, like wild birds, to the mere animal impulses of the blood: but, in dealing with them, one must also make allowances, as they say, for the fire within, and know how to open the cage now and then. It is not for you, however, that I say this, young lady: you are no longer a little child; but it may happen that you may have some to take care of some day. Believe me, then, you must not expect too much wisdom from them, and you must allow them to change their perch every now and then. It is a law of our Almighty Father that little children, and little birds, should not stay too long in one place. The mechanism of the circulation is here the same as with us, and does not offer any important peculiarity. Only the left ventricle of the heart has walls of extreme thickness, which enable it to launch the blood into the members with greater vigor and rapidity; and the blood itself, although it is composed of precisely the same materials as that of the mammals, differs from it nevertheless as regards the globules. In the first place, they are more numerous; secondly, they are larger; and finally, instead of being round like a plate, they are drawn out ovally, and are almost shaped like those long dishes on which fish is usually served. I shall not attempt to give you the reason of their size and form. This is hidden from us in the same mystery which envelopes all the microscopic population of the blood; but is it not a curious thing, this strange persistency of form in the globules ofall animals of one class? In all birds they are oval; in all mammals they are round. In all? Nay, I am wrong. As if the better to hide from us the key to this riddle, nature has amused herself by making an exception. Camels and llamas, I forgot to tell you, have also globules in the form of long dishes, like the hen and the chaffinch. Find out why, if you can. As to the reason of the number, it is a very simple one. Since the energy of the blood resides in the globules, it follows that the most energetic blood will contain the largest amount of globules. Looking at you, for instance, little monkey, running and jumping about the garden, I would lay a wager, without counting first, that there are, in one drop of your blood, some millions more globules than in one of mine. Let us now go on to the digestion, with which, properly, we ought to have begun; but I preferred pointing out to you, first, the particular character which is the chief mark of distinction in the organization of the bird. 'When hens grow teeth,' says a shrewd proverb, meaning of course, _never_. Birds have no teeth, and in this respect there is no variety among them. All, from the first to the last, have uniformly the same tool to eat with--the bill, that is--which is, in all cases, composed of the same elements, two jawbones elongated to a point, and clothed in a horny armour, which makes their edges sharp and cutting. At the same time were we to review the birds in detail, as we have done the mammals, you would see that there are almost more modifications to be observed in this one single instrument than in our thirty-two teeth. All birds have a beak, but each has his own, organized expressly with reference to the kind of food needed by its owner. The eagle's beak, which mangles living prey, is pointed, bent, and hard as steel; the bill of the duck, which laps up water from ponds and puddles, in order to get worms and half-decomposed refuse out of it, is soft, and flattened like a shovel. The woodpecker's, which has to pierce the trunks of trees, is like a pickaxe; that of the humming-bird, which has to suck up the juice of flowers from the bottom of their corollas, is slender as a needle. The swallow feeds on flies, which it snaps up on the wing, and has a soft bill, which opens like a little oven. The stork picks up reptiles in the mud of the marshes; its beak is straight-pointed, cutting as a knife, and resembles a long pair of pincers. The sparrow feeds especially on hard grains, difficult to break; accordingly its beak is stumpy, short, and thick, and is arched on the upper side for still further solidity. But I should never end if I began to enumerate all the thousand varieties in the bills of birds. Each variety, too, corresponds with some peculiar sort of life, and consequently with a general conformation (easily ascertained) of the animal in which it appears. Give a naturalist the bill of a bird--only its bill remember--and he will tell you half its history without fear of being mistaken. On the other hand, we must not deceive ourselves as to the real value of this complaisant bill. Let it transform itself as it pleases into all manner of forms for the better fulfilment of its task, it makes, at the best, but a very poor instrument for mastication; nay, to say the truth, it breaks, cuts, and tears, but it never masticates at all. Thus the bird's mouthful is far from undergoing as perfect a preparation as ours does. It is no sooner taken in than it is swallowed, and the salivary glands, which are still to be found under the tongue, seem only to be there as a matter of form; what little saliva they produce is thick and sticky, and has none of the qualities necessary for making that liquid paste which our tongue sweeps up from every corner of the mouth. Besides, it must be owned that a bird's tongue would be a very awkward implement in such a task. Open a hen's bill and you will see therein a very inferior sort of porter. It is merely a dry hard lance, as it were, armed with prickles at the point, as ill-qualified for tasting as for sweeping. So the hen does not waste her time in finding out the flavor of what is thrown to her. She picks up and swallows over and over again, without appearing to experience any other pleasure than that of satisfying her appetite. Birds of prey, it is true, have rather more convenient tongues, capable, moreover, of tasting up to a certain point; and the parrot, who is a complete epicure, and chews his food philosophically, has a charming-little black one, thick, fleshy, and susceptible--a true porter, in fact-who enables Polly thoroughly to enjoy her breakfast. But certain birds who live on insects surpass even the hen in the dryness and hardness of their tongues. That of the woodpecker, especially, is a model of the kind, and deserves a few words more than the others. Picture to yourselves a long pin, terminated by an iron point with barbs like those of fish-hooks. An ingenious mechanism enables the bird to dart it out with the rapidity of lightning, far beyond his bill, upon the insects to which he gives chase. The point pierces them, and the hooks retain them, without any need of assistance from the bill. I have just told you that this bill pierces the bark of trees; but it only plays the part of gamekeepers on grand sporting occasions, who beat the bushes to make the game rise. The woodpecker's bill routs up the insects by destroying their shelter; but the real sportsman is the tongue. Good-bye to any notion of a cosy little chat in such a porter's lodge as that! What could a harpoon have to say for itself? Do not, however, let this miserable entrance-hall alarm you, at the same time, for the fate of the mouthful thus presented half-dressed to the �sophagus. You will find it only so much the better treated within. In the first place, the �sophagus, when half-way down to the stomach, swells out suddenly and forms a pocket, which is generally particularly well developed in birds who feed on grain; this is called the _crop_ in English, in French _jabot_; whence comes the application of that word to those full shirt-frills which have sometimes been the fashion. It is the pigeon's _crop_ that gives him the rounded chest over which he bridles so prettily. The crop is a receptacle where the food makes a halt: it is something between the pouch of the monkey and the paunch of the ox; a preparatory stomach, which does not, it is true, send back the grain to the bill, for the bill could do it no good, but in which that grain lies until there is room for it further on. Prom thence it resumes its journey; but, before reaching the true stomach, it passes through a second enlargement of the oesophagus, whose walls are pitted with numberless little cavities, from which pour over it the juices destined to supply the place of the saliva that was wanting above. It reaches its destination at last, but still hard, and generally whole. No matter, however. The stomach which receives it, and which is called the gizzard, is quite a different sort of thing from a useless membrane, thin and delicate like ours. It is a thick muscle of enormous power, lined inside with a kind of horny skin, so tough that nothing can break through it. You may form some idea of the prodigious strength of this organ, when I tell you that turkey-fowls have been made to swallow hollow balls of glass, so thick as not to break when dropped to the ground, and that at the end of a few days they have been found reduced almost to powder in the uninjured stomach. No fear of indigestion with such an apparatus as that. Though the grain may not have been masticated in the bill, what does it signify? There is a power here, as you see, quite equal to carrying the whole work through. Thanks, indeed, to the invaluable horn which lines it, fowls which have no teeth of their own can safely present themselves with as many and as hard ones as they please. They swallow small pebbles, which rub against the grain, during the contractions of the gizzard, and act just as effectually as if they were fixed in the jawbone. Well, this terrible gizzard performs its crushing work with such energy, that not only the grain but the pebbles themselves are ground down there, and end by being pounded into fine sand. When you rear fowls, do not forget, if you keep them shut up, to put within their reach a store of small pebbles, so that they may have teeth to run to in time of need. You remember the _pylorus_--the porter down below, who keeps the door of egress from our stomach? He is as badly provided for here as his fellow-workmen up above; worse in fact. It is a gaping hole, and we cannot expect a very strict supervision from it. Birds who feed on fruits profit by this fact to carry vegetables from one country to another. With such an easy opening, seeds have a good many chances of passing from the stomach unaltered; and then they drop from the clouds, as is supposed, hap-hazard, and germinate afterwards, when circumstances prove favorable, to grow up before the astonished eyes of the natives into plants of which they have never even heard. The French Acclimatization Society, which I spoke of lately, and which, though so modern, has correspondents all over the globe, is at this moment laboring to effect an exchange between all countries of the natural productions of their soil. But here you see that nature had thought of this before, and established her acclimatization society long ago. To complete the internal work of digestion, so feebly begun in the bill, an extremely large liver pours torrents of bile into the duodenum, and the manufacture of chyle proceeds with that wild rapidity which characterizes all the living actions of birds. But speaking of this liver, I think I ought to give you an account of a celebrated dish, considered a great dainty by epicures, called _pâtés de foies gras_--_fat liver patties_, to translate it into its meaning. Very likely you will not care to eat them after hearing my story; but that will be no great loss to you, for it is a very indigestible sort of food, and not at all good for children. You remember my telling you about Englishmen going to India and coming back with a liver-complaint, from having eaten and drunk more than the climate allowed? By an imitation of this process, human ingenuity--occasionally so cruel--has created the _pâtés de foies gras_, the glory of Strasburg. I have been in the country, and can tell you how it is managed. They shut a goose up in a square box, where there is just room for his body. They open his bill at feeding-time, and cram down with the finger as much food as can be got in. This is throttling rather than feeding it. The poor beast, who can use no resistance, since it cannot move, and who is kept in the dark to prevent excitement; the poor beast is quite unable to burn all the mass of combustibles with which the blood soon finds itself loaded. This carries them to the liver to be turned into bile; but the liver is not equal to the work, becomes loaded in its turn by unemployed materials, and grows and grows, till at last, having filled up all the space around it, it stops the play of the heart and lungs. When the animal is nearly suffocated they kill it; and this is how we come to have _pâtés de foies gras_ to eat! If they give us a fit of indigestion afterwards, it is a vengeance we richly deserve. At Toulouse, where the same trade is carried on on a large scale, they used formerly to go even beyond this. They fastened the goose by the feet before the fire-place, after having put out its eyes. The imitation of the Englishman's proceeding was still more perfect here, for the fire acted the part of the Indian sun to perfection. I do not know that part of the country well enough to tell you whether they have quite given up this piece of wicked ingenuity; all I can say is, I devoutly hope so. The intestine of birds is much shorter than that of mammals. Here everything is done at full gallop, and the chyle has not to go far before it is absorbed. I have before me a book, in which I am told that the wagtails eaten in France can be fattened in twenty-four hours, if you only know how to set about it, and these birds are not rare; they belong to the same family as the red-breasts, the tomtits, and the nightingale. Thrushes and wheatears (ortolans) require, for the same purpose, four or five days in the same country, left to themselves to roam about, when the vine keeps open table for them. This incredible quickness, not only in digesting, but, what is much more, in transforming food into fresh living material (_assimilating_ it, as it is called), has often a fatal result for the bird. He is prohibited from fasting; his life is a fire of straw, which must be replenished unceasingly, or it will die out in the twinkling of an eye. Our own little birds--children--eat oftener than grown-up people, and if by any accident they are kept waiting awhile, they soon cry out with hunger. You know this, do you not? Well, then, if any one should give you a bird to keep in a cage, remember that you have undertaken a great responsibility, and that it will not do to be careless with him. To neglect feeding him for one day is to run the risk of finding him starved to death next morning. With this warning, I will conclude my chapter on birds. I hope I have not spoken in vain in behalf of those poor little captive songsters, whose fragile lives are at the mercy of their young masters and mistresses. LETTER XXXV. REPTILIA. (_Reptiles_.) Passing from birds to reptiles is like falling from a torrent into still water. Life drags on as sluggishly with the second as it dashes furiously forward with the first. I spoke to you just now about a fire of straw: now we have a fire such as Frenchwomen make in their _chaufferettes_, or foot-stoves. A handful of charcoal-dust, and a few live embers between two layers of ashes, is enough for the whole day; which is economical, is it not? but then it throws out only just warmth enough to keep one's feet comfortable. And so it is with reptiles. They live at very small expense. If you feed them once a month they will not complain, for so slow a fire does not often need replenishing with combustibles. It is even said that the experiment has been carried so far with tortoises that they have been made to fast for more than a year, and still the charcoal fire kept up its languid pace. Of course, on the other hand, there is not nearly so much oxygen consumed at once upon such a diet as this. Where a bird would perish twenty times over in five minutes for want of oxygen, a lizard can remain whole hours with impunity. Moreover, the animal heat of reptiles is in proportion to their expenditure of it. Graceful as is the snake (that living jewel so often copied by bracelet-makers), you feel on touching it an instinctive horror, caused by the thrill of cold it produces. All the animals we have considered hitherto have warm blood, and bear within themselves the source of their heat, which is pretty nearly always the same. But reptiles are cold-blooded, and heat comes to them chiefly from without. If, at the end of a cold winter, we go to some favorable corner to catch the first rays of spring sunshine, we feel ourselves almost re-born, as it were, as if a new life had come into us with the sunbeams. Look at the little lizard you see frisking on the white stones of the wall; upon him decidedly the sun is darting actual life from its rays. While the cold lasted he staid squatting in his hiding-place--not asleep, but annihilated--congealed, so to speak, like water caught by the frost; no longer digesting, and hardly breathing, he had ceased to live in reality: and it is no imaginary regeneration which the return of warmth brings to him. Like those helpless people who have not the power to carve out their own destinies, reptiles have within them only an insufficient source of animation; their life is at the mercy of the sun, and is high or low, according as that rises or sets in the heavens. At Martinique, where at noonday it darts its devouring rays perpendicularly upon the cane-fields, and every one flies into the shade to escape its scorching heat, the rattlesnake traverses the country, monarch of all he surveys; he strikes rapidly with a vigorous tail upon the calcined ground; and woe then to any one who receives his bite! All the fire of the atmosphere has passed into his frame. Now go to the Zoological Gardens, and see him there: he crawls languidly under the coverings that shelter him; if by chance he bites any one, it is with an idle tooth that no longer knows how to kill; his life was left behind with the sun of the tropics, and it is little more than a corpse that you are looking at. And so among ourselves, my dear child: we meet with people whose whole power comes from without, who are brilliant and haughty in the sunshine of good fortune, but crest-fallen, cowardly, and cringing in the cold days of adversity. Nevertheless, they are constituted originally like other people: they are neither greater fools as a general rule, nor less gifted than their neighbors; where they fail is in the heart, but that is enough to spoil everything. And so with reptiles: the heart is their weak point also. Like us, they have lungs into which the air pours without any difficulty, and a heart to send the blood to them; so it seems at first sight as if there could be nothing to prevent their resisting the changes of external temperature just as well as ourselves. There is only one small trifle wanting, and that is a partition in the middle of the heart; but this one defect is enough to disorder the whole machinery. You know that, with us, the heart is divided into two compartments: the right ventricle, which receives the venous blood from the organs and sends it to the lungs; the left ventricle, which receives it (now become arterial) from the lungs and returns it to the organs. Hence the double system of veins and arteries, the one going from the heart to the lungs, the other from the heart to the organs. All this is found the same in reptiles: except that the partition, which separates our two ventricles from each other, does not exist in them; and the heart has only one common room, in which, therefore, arterial and venous blood become mixed together. It follows from this that, at each contraction of the heart, it is a mixture of arterial and venous blood which is sent in the two opposite directions at the same time, and that the organs receive some which has been used before, while the lungs have some returned to them which has been regenerated already. Now, on the one hand, this mixed blood can only keep up an imperfect combustion in the body (like the live embers between two layers of ashes that we spoke of lately), and, on the other hand, the air in the lungs can only act upon a part of the blood it meets with there, the rest having already undergone the regenerating process. And this accounts for both the feeble animal heat and the small consumption of oxygen in reptiles. Added to which the lungs of a reptile are coarsely constructed, and composed of cells enormous in comparison with ours, so that the blood does not find nearly as many little chambers to rush into for a taste of air as with us. Moreover, you must understand that there is no such thing as a diaphragm here: the lungs float loosely in the form of elongated bags in the one only cavity of the body, and the slight movement of the ribs does not allow them to dilate sufficiently to take in much air at a time. All these things, taken together, make the reptile a very poor stove, and render him incapable of any prolonged exertion. The serpent darts like an arrow upon his prey; but he could not pursue it for half a mile without stopping, not even over the burning soil of the equator. The lizard is very nimble, is it not? and the quickness of its movements rather reminds one of the agility of a bird. But watch it, and you will see it only moves in jerks, and keeps stopping every minute; it cannot escape you if there is no hole near into which it can disappear. In France there is a large green lizard that runs among the vine trees. If you pursue him he is off like lightning for a second; then he stops suddenly short. You return to the charge, and he starts afresh, but only to stop again. At the fourth or fifth attack he is quite out of breath; you poke him with the stick with which you have been hunting him, but in vain; there he lies motionless, in spite of his alarm. A few steps have brought him to the end of his powers, like a man whose heart is diseased and who cannot go far. This, however, is a peculiarity common to all reptiles. Each of the three orders of which this third class of Vertebrata is composed has its own particular history besides. You must excuse my mentioning the barbarous names that have been given them, and allow me to call them _tortoises_, _lizards_, and _serpents_, like other people. The hard names mean no more than these; but they are Greek, which is always more imposing. The slowness of the tortoise has passed into a proverb, which is not to be wondered at; for they cannot inhale the air, because their ribs (which are a reptile's only resource for breathing) are condemned to absolute immobility. The _carapace_, or shell, which the tortoise carries on his back, and under which it retreats upon the least alarm, as under a shield, is really formed of its ribs, each of which has widened itself so as to join on to its neighbor, like the boards of an inlaid floor, which run one into another. Of course there is no question of moving up and down with such ribs, and the poor bellows cannot work at all. How does the tortoise get out of this difficulty then, you will ask? I answer, it swallows air, as we should swallow a glass of water. You see its mouth open and then shut again, thereby taking in an actual mouthful of air, which the sides of the mouth, by contracting themselves, send straight to the lungs. These, which are very large, get filled in this way by degrees, and, when they are quite inflated, they expel the overplus by collapsing, like an over-stretched spring. You may imagine that this does not produce a very active respiration, and that a tortoise would be puzzled to run at even a moderate trot. To be sure, when he has once filled his great lungs with air, he has enough for a long time. Most tortoises are aquatic, and, as divers, leave the cetaceans far behind. Méry, an obscure French naturalist of the days of the Empire, pretended that he had kept in his house, _for a month_, some tortoises, whose breathing he had completely stopped. Only imagine from this how far their life must be below ours, although it is the result of similar actions, performed by organs which after all are copies (imperfect ones, it is true) of our own. Some tortoises feed on vegetable substances, and some upon fish or small soft-bodied animals. Like birds, they mash their food with difficulty, by means of a real bill. Their jawbones are generally arched forward toward the front, and are furnished with sharp horny plates, in which a fairly-marked denticulation or notching may sometimes be traced, as in the bills of birds of prey. Indeed there is one, the _caretta_, whose hooked and notched beak so completely recalls the warlike bill of a hawk, that it is usually known by the name of the "Hawk's-bill Turtle." You ought to know about this tortoise, for it is the one which furnishes tortoise-shell, that nice material which is so smooth to the touch, so pretty to look at, and so very fragile, that it seems only fit for the use of ladies' hands. I could hardly speak of tortoises without saying something of this one, out of whose back was carved the handle of your own pretty little penknife. Behind this bill of the hawk's-bill there is a tongue, but of the character of a whale's tongue, and it is fastened underneath to the bottom of the mouth. At the base of it there is a sort of fleshy pad or cushion, which serves instead of a soft palate, that being another detail which is about to disappear from our history. We are now really entering upon the simplification of the digestive tube, which will, I forewarn you, end by being nothing more than a perfectly straight pipe, without any appendages whatever. In tortoises the intestine is still tolerably long, and is doubled up backwards and forwards many times in the abdomen; but it is already beginning to lose that variety of form which its different parts assumed in the higher animals. The large intestine can no longer be clearly distinguished from the smaller one, nor this from the stomach, which itself seems to be a continuation of the oesophagus, without any very distinct boundary line between them. The porter, who with us keeps the door of the stomach, does his duty here so badly, that there are certain kinds of tortoises whose oesophagus is covered with spines, the points inclined backward, to prevent the food from rising up into the mouth whilst the oesophagus is driving it down by its contractions. In the gray lizards of our walls we find teeth again, but very different from any that we have hitherto seen. In the first place, they are not content with their usual place on the edge of the jaws, but encroach upon the surface of the palate, where they stretch out in close lines. Besides, they are even still less like teeth than the great nails in the jaws of the cetaceans. They are little ivory prongs, with the points turned inwards, analogous to the thorns of the oesophagus in the tortoise, and serve the lizard solely to retain and bruise his prey. He lives on insects, especially flies, which he seizes on the wing with the greatest skill, hastily catching and engulphing them in his open jaw; they pierce themselves on the little prongs, and are swallowed promiscuously. The tongue of the lizard has also a curious peculiarity, which is shared by that of the serpent: it is divided at the end into two threads, which dart in and out of its mouth, and by means of which it laps, like a dog, the few drops of water it requires to satisfy its thirst. I have seen lizards which had been tamed by children greedily sucking up the saliva from their lips by drawing across them those little forked tongues of theirs, which, after all, are very soft, and perfectly inoffensive. The tongue of the chameleon, another species of lizard, is still more curious. You must know that the chameleon is a lumbering lazy animal, who feeds on flies and other swift insects, and who would, therefore, be constantly liable to go without his dinner but that his tongue serves him for a hunting weapon, like those of the wood-pecker and the ant-eater. When at rest, it is an oval spongy mass, lying comfortably in the mouth, with nothing formidable in its appearance; but let the prey come frisking round the chameleon, as if despising so helpless an enemy, and this great soft tongue is transformed into an active dart. It shoots forth like an arrow, and will sometimes seize the rash intruder at half a foot's distance, transferring it with equal rapidity to the motionless mouth. The blow is so soon struck, that it is very difficult to see how it all happens. Some say that the chameleon curves the tip of his tongue by a sudden effort, and then catches his flies with it, just as you would catch them with your hand. Others maintain (and this is the general opinion) that the tongue of the chameleon is terminated by a sort of sticky cushion, on which the flies are caught, like birds with birdlime. This singular dart is always out-jerked with such force that, if it strikes against a glass (the experiment has been tried with chameleons in captivity), it makes a sound as loud as that of a pea from a pea-shooter; so you may judge if it is not strong enough to stun a fly. Besides this, too, the chameleon (who is by-the-by, a hideous little beast) has given endless trouble to naturalists on another and very different point. It is he who is so celebrated for his faculty of changing color when any emotion agitates him; and ever since the days of Aristotle, who lived more than two thousand years ago, people have been trying to explain this, without any one being able to flatter himself that he has found out the exact answer to the riddle. But there is a lizard more interesting still, and that is the crocodile. He stands alone among reptiles. His heart has two ventricles, and you would think that he ought to be included in the class of warm-blooded animals. But, no. The separation of the two kinds of blood takes place in the heart, it is true, and it is really true arterial blood which the aorta carries away from the left ventricle. But the right ventricle has two doors of exit. One communicates with the lungs, the other with the aorta; and the latter has hardly performed its distribution in the upper part of the body when it meets, as it descends, with a treacherous tube bringing to it a current of venous blood. In this way only half the blood that comes from the veins passes on to be regenerated by contact with the air, and all the hinder part of the body receives nothing but the mixed blood common to reptiles, while the head and fore members enjoy the privilege of the superior orders. After this go and lay down your laws of classification! Nature, while maintaining amongst all animals the same principle of life--the regeneration of the blood by oxygen--has in their construction followed many systems leading to the same result by different combinations, and which seem to permit the establishment of essential distinctions among them. Here is an animal who, if I may so express myself, is climbing up from one system to the other, and you would have to cut him in two before you could classify him properly, since his fore-quarters have risen to the warm-blooded animals, while his hind ones are left behind among the cold-blooded reptiles! But there is something which even outdoes this. On dry land the crocodile is timid, faltering, a bad walker, incapable of regular combat, and a man can manage him with a stick. One feels that he is betrayed by the hinder half of his body, through which circulates the only half-oxygenized blood. But when once he has plunged into the water his whole behavior suddenly alters; he is a ferocious being, high-mettled, indomitable, a savage enemy, redoubling his exertions, as if the entire mass of his blood had suddenly become arterial. Geoffroy St. Hilaire, who followed Bonaparte as a scientific explorer when he set out for the conquest of Egypt, the country of crocodiles, was deeply struck by studying on the spot this double life, which seems in a way to maintain two beings in the same body. He afterwards gave an extremely curious explanation of it in his work on the crocodiles of Egypt. Here it is; but I forewarn you that you will not understand it: "The crocodile, when it is under water, receives by two canals into the cavity of the abdomen, a considerable quantity of water, which the animal can renew at will." You are not much the wiser, are you? But wait a moment. We are soon coming to the fishes, and you will then see what an unlimited scope nature has allowed herself here. Not satisfied with two systems in one animal, she appears to have got hold of three. If we continue the examination of this privileged reptile, we shall find many other infractions of the usual rules of his class. His tongue, certainly, is fastened to his mouth like that of the tortoise, so much so that the ancient Egyptians told the Greeks he had not got one; but his set of teeth clearly approach those of the lower mammals. You have probably heard a great deal of the strength of the crocodile's formidable teeth. Travellers have given them this reputation; but we have nothing to do with that now. They stand in battle array, in a single line, along the whole length of the jaws, into which they are sunk with genuine fangs, whilst the prongs of our little lizard are merely fastened to the surface of the bones which support them. Indeed, in one way, the crocodile is even better provided than the mammals. He possesses under each tooth one or two germs, the life of which lasts as long as that of the animal, and which are always there ready toreplace the previous one should it chance to fall out. There are many ladies, and (not to be rude) gentlemen as well, who would, I am sure, give a great deal to have as many teeth at their service. Indeed, they may possibly think Dame Nature very unjust to have selected this great villanous beast rather than us as the object of a gift which they would have been so well able to appreciate. But we must not blame nature too quickly: she had her reasons. We, during our infancy, have teeth in reserve. Now, a reptile may be considered as an imperfect rough draft of a mammal; and the crocodile gives one thoroughly the idea of a mammal half-finished and fixed for life in a state of childhood. I am sorry that I cannot enter into full details, that you might see how far the idea is a just one. Moreover, in his character of a perpetual child, he is always growing bigger all his life long, and never seems able to die but by accident, hardly ever, I may really say, from old age. By specimens kept in captivity, it has been ascertained that their growth is very slow. Well, imagine their being only from seven to eight inches long when they come out of the shell, and that full-grown crocodiles have been found thirty feet in length, and calculate accordingly. You will not account for it under a century; and I should like to know what would become of this venerable child of more than a hundred years old if kind Mother Nature had not left him our system of milk-teeth to the end? A curious peculiarity of these persistent teeth is, that they are hollow inside, so much so, that the bowls of tobacco-pipes are said to be made from them in Europe. I mention the fact, although of no great interest to you, for the benefit of any pipe-merchants who have not yet thought of sending for such things to Cairo. But let us return to the efforts perceptible in the organization of the crocodile to raise itself to a higher level. The soft palate, as we called it (Letter VII.), is wanting in other reptiles; but here there is one which completely closes the entrance of the windpipe (the larynx). I announced, too, the disappearance of the diaphragm; and we bewailed together the loss of that servant of the good old times, whose touching history you must, I am sure, remember. But I reckoned without this wretched crocodile, who seems determined to give the lie to all we have been saying. He has a diaphragm, and one which acts well enough in the main, although it is pierced right through the middle, as if it were rather ashamed of being there, and wished to make up for dividing the body into two compartments, against all proper reptile regulations, by opening a door of communication between them. What shall I tell you besides? The lungs, not to be behind the rest of this aristocratic reptile's organization, are hollowed into cells much more complicated than those of his fellows. You find here no end of nooks and corners, which multiply opportunities of contact between the air and the blood, and so give the crocodile almost the respiration of the mammals, as he has already got pretty nearly their system of circulation. With serpents, again, we fall very low. When we were speaking of the tortoises I told you that, in proportion as we come down in the scale, the digestive tube has a tendency to get rid of its accessories, and to assume the appearance of a perfectly straight tube. If any one were to cut open a serpent before you, you would see this final condition almost reached already. In the first place, the soft palate is entirely suppressed, and the mouth extends straight into the oesophagus, whose tube seems to run through the whole length of the body without interruption, with just four or five doublings towards the base, in that part which represents the intestines. An imperceptible swelling indicates the place where the real stomach lies within; but in another sense one may call the oesophagus, and I might almost add the mouth itself, its stomach. You shall see how. The jaws of serpents are even in a more unfinished state than those of other reptiles. Nature has not taken the time to weld the different parts of them together; but these begin by not being very firmly joined, remember, in young mammals. The bones of the head, which support the jaws, are themselves movable, and can be detached from the skull if necessary, so as to allow the throat to open extraordinarily wide; thus it is not uncommon to see a serpent swallow animals much larger than itself. You will be horrified when I tell you that the anaconda, one of the giants of the family, swallows large quadrupeds at a single mouthful. What are our mouthfuls in comparison with his? however, it must be confessed, that his often take several days to go down. When the animal has rolled up his prey in his terrible folds, he pounds and kneads it till it is reduced to a kind of long roll, which he moistens with a copious slaver to make it slip down more easily. Then, attacking it at one end, he fastens this very expansive jaw upon it, and the gigantic mouthful slowly begins its journey; what was left outside the mouth, advancing little by little, in proportion as the digestion reduces what has entered to pulp, and sends it farther down. This is on great occasions; but in the case of more modest prey--a rabbit, for instance--the mouthful goes in whole at one gulp and remains stationary, partly in the oesophagus, partly in the stomach, while the powerful juices distilled by the walls of the latter are dissolving it. You can see that a soft palate would have been quite useless here, and that the serpent has not much need of teeth to chew his food. Accordingly, his are nothing but simple prongs, like those of the lizard, and, like his, they extend over the palate, the more effectually to cut off the return of the swallowed masses of food. About a hundred and twenty have been counted in the throat of the boa-constrictor; but their number varies considerably in the different species. They are not organs of the highest order, and nature is not very particular about the quantity. There is only one tooth among serpents of which she takes any particular care, and that is the venomous tooth which she has bestowed on certain species, and which serves them for striking down, as it were, the animals on which they feed. Let us study it in the rattlesnake, the most celebrated of this odious race. On each side of the upper jaw you may see, isolated from the others, and exceeding them all in length, a very sharp fang pierced through by a tiny canal, which opens into a gland placed at the root of the tooth. The bone which supports this little apparatus is very flexible, and when at rest, the fang, falling back, hides itself in a fold of the gum. When the animal wishes to bite, it springs up again, and the gland, compressed by the action of biting, sends into the little canal a jet of poison, which runs through it into the wound. As far as can be ascertained, this poison paralyses the victim and disorders the blood, which at once loses its power, and no longer acts upon the organs as before; still it is only injurious when it has been carried by the current of circulation into the mass of the blood; if swallowed, it has no effect whatever on the stomach. Now do not look at me with such incredulous eyes, as if it were quite impossible any one should think of swallowing such a thing. You have no idea what a scientific man is capable of when he comes to close quarters with nature, for the purpose of extracting one of her secrets. He has his own fields of battle, where very often as much courage is displayed as on any other. These two fangs, in which lie all the power of the animal, are of the greatest importance to him, and their want of solidity makes them liable to remain in the wounds which they have made. In consequence of this, they enjoy the same privilege as the teeth of the crocodile, and in a still greater degree even. Behind each poison fang lie in wait, not one nor two, but several sentinel germs, ready at the first alarm of a loss to set to work and re-supply the disarmed serpent with his venomous needle. So the serpent also lives in a state of perpetual childhood: he is always growing; and I could not tell you the exact natural limits of his life any more than of that of the crocodile. They are gentlemen who do not allow themselves to be very closely studied in a state of freedom. But these also grow very slowly, and some have been met with whose size had extended quite enormously from their first start. I ought to tell you, once for all, that this indefinite growth, joined to extreme longevity, is found in many of the inferior species whom we have yet to consider. It seems the portion of these unfinished creatures, in which nature has only as it were sketched in her work, and who seem vowed to endless youth, in testimony of the state of childhood they represent, a state transitory among the superior animals, but permanent with them. It belonged of right, therefore, to the serpent, which is the most unfinished animal we have yet met with, and who, at the first glance, seems almost reduced to a mere digestive tube, lodged between a vertebral column and a series of small ribs, whose number sometimes reaches three hundred. The liver, which, with us, presents such a distinct and bulky mass, is here elongated into a thin cord, which runs the whole length of the oesophagus and intestine, to the walls of which it is, to some extent, attached. It is the same with the lungs. There is rarely room for the full development of two in this narrow conduit, where everything has to follow the shape of the master of the house: one, therefore, is often merely indicated by a very slight protuberance; the other, presenting the appearance of a long tube, which extends nearly half-way down the body, and whose feeble action halts periodically at each of those monstrous repasts, after which the torpid animal becomes nothing but a huge digesting machine. We have now reached the extreme limits of that organization, the most perfect model of which we find in man, and which is no longer to be recognized in fishes. LETTER XXXVI. PISCES. (_Fishes._) We are becoming terribly learned, my poor child, and I am half afraid you will be getting tired of me. When I was little myself, I had rather a fancy for breaking open those barking pasteboard dogs you know so well; to see what was inside them. Why should you not, then, feel a certain amount of interest in looking with me into the insides of real animals? Still I cannot conceal from myself that the subject grows very serious at last, and that while I am busied in struggling to make myself intelligible through the endless crowd of facts which surround me, I am apt to neglect chatting with you as we go along. Happily, however, here is an opportunity for so doing. Up to the present time we have lived, as it were, upon the explanations I gave you whilst studying the action of life in yourself, and all the organs we have met with since, have been only, properly speaking, reproductions, more or less exact, of those which you yourself possess. But, in passing over into the kingdom of fishes, we find ourselves in the presence of something altogether new, and I must go back to our old familiar style of talking to open the subject. Take a water-bottle half-filled with water, and shake it well, and you will see a quantity of white froth come to the surface of the liquid. This is the air which having been drawn in by the water, as it went up and down in the bottle, is now struggling to fly off again in bubbles as fast as it can. But the whole of it does not get away; a small portion remains behind, and melts, as it were, into the water, as a morsel of sugar would do, taking up its abode therein. This seems odd to you, but I will tell you how you may convince yourself of the fact. Get a small white glass bottle, slightly rounded, and thin at the bottom, if possible; fill it with water, and hold it for a short time over a lighted taper. If you do this carefully there is no danger. You will soon see tiny little balls, looking like drops of silver, rise from the bottom of the bottle, come up to the surface, and burst. This is the air which was installed in the water, as I described above, and which is now running away from the heat of the candle, as the inhabitants run away from a house on fire. After a time the whole will have passed off, and the little balls will cease to rise. But what has all this to do with fishes? you ask. A very great deal, I assure you, dear child. If there had been a little fish in your bottle, before it was exposed to the flame, it would have found means to make use of that air, whose original presence in the water you cannot refuse to believe after having seen it come out. It is with this air that fishes breathe in the water. They do so rather feebly, I admit; but, as if to make up to them for the small amount of the air placed at their disposal, it contains more oxygen than that we breathe ourselves, because oxygen, dissolving more readily in water than nitrogen, is there in greater proportion. Of course, you do not suppose that fishes have lungs like ours? I dare say you know the two large openings on each side of their head, called _gills_, by which the fishermen string them together to carry them away more easily? It is there you will find their lungs, to which the name of _branchiae_, or gills, has been given, because they are so different from other organs of respiration that it was impossible to use one word for the two. The arrangement of the gills varies considerably in the different species, but their general form is the same everywhere. They are composed of a number of plates, consisting of an infinitude of leaflets, arranged like a fringe, and suspended by bony arches, into which plates and leaflets the blood pours from a thousand invisible canals. First of all, then, we must see how blood circulates in fishes. Like reptiles, their heart has only one ventricle, and yet the arterial and venous blood go each its separate way without the slightest risk of being mixed; but this is because fishes have not that double system of veins and arteries which hitherto we have always met with. The venous blood goes to the heart, which drives it into the gills, from whence it passes forward of its own accord, as arterial blood into the organs, under the remote influence of the original impetus from the heart, the newly-arrived blood incessantly driving the other before it into the vessels of circulation. It does not flow very quickly, as you may suppose; and as the heart is close to the head, its action is but very feebly felt at the extremity of the body, when this happens to be very long. Nature has, in consequence, taken pity on the eel, whose tail is so far from its heart, and provided accordingly. Dr. Marshall Hall has discovered near the tip a second, reinforcing heart, so to speak, which has its own pulsations, independent of the pulsations of the one above, and gives a fresh impetus to the sluggish blood, [Footnote: Many observers refer this to the lymphatic system.--TR.] which otherwise, as it would seem, would scarcely be able to accomplish the long return journey. Finally, even with an additional heart in thetail, the circulation among fishes is quite on a par with their respiration. They have a melancholy steward, whose legs are very heavy, and his pockets very light, and their life comes down a peg lower in consequence. It is always the same life nevertheless--you must never lose sight of that fact: it gets low in consequence of the imperfection of the machine, but without changing its nature, any more than the light in our different sorts of lighting apparatus. You remember that comparison of the lamp with which I began my story, and which you could not at the time see the full value of? From a dungeon lamp up to a candle, you have always grease burning in the air at the end of the threads of a wick. It does not burn equally well everywhere, and does not always give the same amount of light; but that is all the difference. From the mammal to the fish, it is always hydrogen and carbon (as we have said of the grease) which oxygen sets on fire in the human body at the fine-drawn extremities of the blood-vessels; only the fire is lower in some than others, and the life with it. Let us now look at the circulation of water in the fish's body. The gills communicate with the mouth by a sort of grating, formed by the bony arches to which the gill-plates are suspended. The fish begins by swallowing water, which then passes through the grating and circulates round the innumerable leaflets of which each plate is composed, and among which creep the blood-vessels. It is through the thin coats of these leaflets that the mysterious exchange is made of the unemployed oxygen in the water and the carbonic acid in the blood. When this is over, the cover which closes the gills opens to let out the water, and a fresh gulp takes its place; and so on continually. When the fish is out of the water its gills fall together and dry up; the course of the blood, already so weak, is interrupted by the breaking down and shrinking of the vessels, and the animal can no longer breathe; so that we have here the curious instance of a creature breathing oxygen like ourselves, who is drowned, if we may use the expression, in the air in which we find life, and lives in the water in which we are drowned. While he is in the water matters take another course, and his gills, moistened and supported, accommodate themselves perfectly to the contact of the air, which desires nothing better than to give up its oxygen to the blood, through the coats of the capillaries. Accordingly you will often see fishes--carps, for example--come to the surface of the water to inhale the air like a mammal or a reptile. This is a valuable resource, which supplements the parsimonious allowance of air given out to them by the water. There are even certain fishes whose gills, more firmly closed than those of others, have, in addition, a number of cells, which retain for a considerable time a sufficient quantity of water to preserve the gills in their natural state. These fishes can easily take an airing on land, where they breathe the air as you or I do, and are downright amphibians. The most celebrated of these is the _Anabas_, or "climbing-fish." an Indian fish, which not only can remain many days out of the water, but also amuses itself by climbing up the palm trees--it is hard to say how--and establishing itself in the little pools of water left by the rain at the roots of the leaves. But we need not go to India to find those wandering fishes. There is one of them living among ourselves who can walk about in the grass, and I was talking to you about him only just now--that is the eel. If you ever put eels in a fish-pond you must, I assure you, try to make it agreeable to them, otherwise they will have no scruple in setting politeness at defiance and moving off to seek their fortune elsewhere. In a country walk, when the dew is on the ground, you yourself may chance to come across one or two of these gentlemen, who have had their reasons for changing their residence, and whom you will see gliding so briskly along that they will deceive you into taking them for snakes if you have not a very experienced eye; so much so, that in certain parts of France where the peasants ate snakes formerly, they reconciled themselves to the sickly idea by christening them _hedgerow-eels_. On the other hand, fishes may be drowned in water just as easily as ourselves if it does not contain air. The little fish who could have lived very well in the bottle we were just now talking about before you exposed it to the flame of the taper, would have died in it after all the air-bubbles had gone off; and I hope I need not tell you why. In the same way, if you leave fishes too long in a small quantity of water without renewing it, they suffer exactly as we do if the air which we breathe is not changed often enough. As soon as they have consumed what oxygen is in the water, it can no longer keep them alive. It is then, especially, you will see them come gasping to the surface to call upon the air for help. Those who keep gold fish in a glass bowl ought to know this, and to change their water oftener than is generally done. When we take poor little creatures from their natural way of life, and set a human providence over them in the place of the Divine one which has hitherto been their safeguard, the least we can do is to acquaint ourselves with the laws of their existence, so that we may not expose them to the risk of suffering by our ignorance. Finally, there are fishes whose gills, still more greedy of oxygen, will not act well except in thoroughly aerated water, and who would soon die in our tanks. This is the case with the trout, who is only happy in the waters of hilly countries; rich with all the air they have carried along with them as they fell from rock to rock. Now that people are beginning to do with fishes what has long since been done with sheep and oxen--keep them in flocks to have them always ready for use--you may perhaps hear a good deal said about vessels made expressly for the carriage of trout, with a thousand inventions besides for sending air into the water, and you will not have to ask the meaning of this now. I promised last time that I would revert in the chapter of fishes to that marvellous transformation of the crocodile which has been explained by the torrent of water he draws into his stomach. You could understand nothing about it the other day; but after what we have just seen the explanation suggests itself. Just as the extraordinary activity of life in birds is explained by that double oxygenization of blood, of which part takes place in the lungs and part in the reservoirs of air placed everywhere in the way of the capillaries, so this sudden increase of energy in the crocodile the moment it plunges into water may be explained by a second respiration suddenly established in the vast cavity of the abdomen, by the contact of the capillaries with the water which penetrates there. Hence the crocodile would then have, like the bird, a double respiration: only with him the one would be permanent and from the lungs, the other temporary and from the stomach. By this, on the one hand, he would rise up to the birds, since the blood encounters air twice over in its course, while, at the same time, he would plunge into the world of fishes, since the blood has to seek air in the water. The above, be it remembered, is only a supposition, and I ought to add that in this case there would be a good deal of danger in observing nature at work, for in front of the laboratory, where she is toiling in secret, stands on guard a row of teeth, by no means encouraging to indiscreet intruders. At the same time, if there ever were a legitimate conjecture, this is it. Everything seems to confirm it; and if it be true, we should have in the crocodile a specimen of each of the four systems adopted by nature for the mammal, the bird, the reptile and the fish. At first I spoke of two, then of three; so that even in my addition I was modestly below the mark, and had really some grounds for recommending our friends the classifiers to beware what they asserted in this case. Talking of puzzling classifications, this is just the place for mentioning the _batrachians_, who have been made into a class by themselves, but who most distinctly belong to two classes at the same time; not like the crocodile by details borrowed from each, but by a fundamental change which takes place at a certain period in their organization. The batrachians are in reality reptiles, but they are reptiles which begin by being fishes, and real fishes too. If you have ever strolled about in the country, you must have often come across those great pools of water which collect at rainy seasons in the ruts of deep lanes. Amuse yourself by looking into them in early summer, and unless the land is too parched and dry, the chances are that you will see quantities of little black fishes, almost entirely composed of a long tail joined to a large head, playing jovially in the muddy waters, and looking as if they had dropped there from the skies. These are young frogs--_tadpoles_, as we call them--and they are beginning their apprenticeship of life. Enclosed in each side of those great heads, they have gills, and they breathe in the same manner as fishes. Presently the two hind feet begin to bud out and grow, little by little; then the fore feet; finally, the tail wastes away till it disappears; and thus insensibly the tadpole is transformed into a frog. Observe here that the tadpole's gills share the same fate as his fish-tail; they wither and disappear by slow degrees, and gradually as they do so, his lungs are developed. The animal changes his class very quietly, and without ceasing to be genuinely the same, although it would be impossible at last to recognize the old individual in the new if you had not heard its history beforehand. This is one of the most striking exemplifications I know of the mysterious process by which nature has insensibly raised animals from one class to another, always improving upon her original plan without ever abandoning it. On the shores of certain subterranean lakes which exist in Carniola, a country subject at this time to Austria, there are to be found batrachians far more ambitious than our frog--namely, the _proteans_. These cumulate rather than change: they become reptiles without ceasing to be fishes, if I may so express it; they develop lungs as they grow up, and yet keep their gills. I could tell you a thousand other particulars about these batrachians if I were to examine them all in succession; for it is a very motley family, in the bosom of which the transition from reptiles to fishes is in some imperceptible manner accomplished; from the frog, which the unanimous consent of mankind has always ranked among reptiles, to the axolotl or siren, who lives in Mexican lakes; and who, feature for feature, is exactly like a carp, with four little feet fastened under him. To be quite in order, the batrachians ought to have followed the reptiles, for their interior organization is the same; but how could I tell you about their gills without explaining that there was air in the water? and I did not want, for the sake of these intruders, whose babyhood-gills only just appear and disappear, to rob the history of the fishes of its most interesting points. Let us be satisfied, then, with this passing glance at a dubious class, whose history is only a repetition of two others, and let us return to our friends the fishes. We have seen how they breathe, now let us look how they eat. The modifications of the digestive apparatus are endless among fishes. The lampreys, who are placed in the lower ranks of the class, carry out to its fullest extent the type which we have already seen indicated in the serpent. The digestive tube is quite straight, without any perceptible swelling, and does not even go the whole length of the body. It comes to an end at some distance from the tail. Among some fishes an odd tendency begins to display itself, which we shall meet with again farther on. The digestive tube, after going downwards towards the bottom of the body, as we have seen it do so constantly hitherto, doubles back, and comes up again to the throat, under which it empties itself. In most cases the stomach is distinct; but it assumes a thousand different forms; as if nature had wished to try her hand in all sorts of ways in the construction of these imperfect vertebrates, before adopting the definite model which was to serve for the others. The liver is enormous, and generally contains a great quantity of oil, the taste of which you will know if you have ever swallowed a spoonful of cod-liver oil; but in most fishes its old companion, the _pancreas_, has disappeared. In its stead you will find, close by the outlet of the pylorus, the open ends of certain small tubes, which are shut in at their upper extremity like a "blind alley," and through which descends into the interstices a thick glairy fluid, given out from their sides or walls. The result is the same, you see, although the organ is different; and, remarkably enough, these little tubes are wanting among fishes, which, like carp, have a species of salivary glands in their mouths, of which the others show no trace; from which one may fairly conclude that these glands and tubes mutually supply each other's places. Here, then, you see an instance of the light which different animal organisations throw upon each other when they are compared together. In fact, this one establishes pretty clearly the real office of the pancreas in the higher races, exhibiting it to us as an internal salivary gland, intended to complete the work only begun by those in the mouth, in the case of lazy people who swallow their food too quickly. There is the same diversity in the mouth as in the intestine. Some fishes, like the skate, have no tongue at all. Others, instead of a tongue, have a hard dry filament, very nearly immovable, and which one would think was put there like a stake, to show the place where the tongue is to be found in the more perfect organisations. There are even fishes, like the perch and the pike, whose tongue is furnished with teeth, or rather fangs; an evident sign that it has forfeited the confidential position occupied by your own good little porter. You must know also that the perch and the pike, like many other of their fellows, have teeth all over the mouth. This invasion of the palate by teeth, which began in the lizard and the serpent, assumes alarming proportions here. It is not merely the roof of the palate which is spiked with teeth: above, below, at the sides, everywhere to the very limits of the oesophagus, the little fangs triumphantly stick out their slender points. It is impossible, therefore, to state their number. Nature has scattered them broadcast without counting, just as she has done with the hairs of the beard round the human mouth; and the comparison is not so impertinent as you may think. They sometimes form an actual internal beard, even thicker than our outer one, and which sprouts from the skin into the bargain. There is one fish whose teeth are so delicate and so close together that, in passing your finger over them, you would think you were touching velvet. This does not refer to the shark, mind. His teeth are sharp-cutting notched blades, hard as steel, arranged in threatening rows round the entrance of his mouth, and cut a man in two as easily as your incisors do a piece of apple. Others, such as the skate, have their mouths paved--that is the proper term--with perfectly flat teeth. The first time your mamma is sending to buy fish beg her to let you have a skate's head to look at. You will be interested to see the small square ivory plates laid close adjoining each other, like the tiles of a church floor. It is in fact a regular hall-pavement, over which the visitors glide untouched, and are then swallowed down in the lump; thus entering straight into the house without having been stopped by the inscription nature has placed over your door and mine--"Speak to the Porter." But all this is nothing compared to the lamprey's entrance-hall, which differs from ours in quite another way. The lamprey, as I have already told you, ranks almost lowest among fishes, and consequently among vertebrate animals, of which fishes form the rear-guard. Indeed, it is almost stretching a point to consider her worthy to bear the proud title of a vertebrate at all; for the vertebral column, so clearly marked in other fishes, where it forms the large central bone, is only faintly indicated in certain species of lampreys, by a soft thread (or filament), which is rather a membrane than a bony chaplet, and at the top of this mockery of a vertebral column is the creature's mouth. If you ever had leeches on, you will remember the sharp sting you felt when the little beasts bit you. Well, the lamprey feeds herself just in the same way as the leech does. Her mouth forms a completely circular ring, which sticks to the prey, and through which runs backward and forward a small tongue armed with lancets. This darts out to pierce the skin, and draws in the blood as it retreats. Round your lips well; dip them so into a glass of water, and draw back your tongue, and you will at once feel the water rise into your mouth. It is by a similar sort of proceeding that leeches relieve people of the blood they want to get rid of; and in the same way the lamprey draws out the blood of the animals upon which she fastens. What a long way we have come already! How very far we find ourselves here from the little mouths we first talked about as chewing their eatables so prettily! With the lamprey we bid adieu to the class Vertebrata--the nobility of the animal kingdom--among whom nevertheless we must distinguish between the peer, who approaches nearest the person of his sovereign, and the inferior provincial lords who live at a hundred miles' distance. There is only one step from the lamprey to the _mollusks_ or soft-bodied animals, and this is the course which animal organisation seems really to have taken in its progress. But nature never moves forward in a single straight line. In passing from the mollusk to the fish to get thence to the higher vertebrates, she turned aside in another direction toward a class of animals which rises far above mollusks, but which leads to nothing beyond. One would think there had been a check here, as if the creative power, having discovered that it was going in a wrong direction, had retraced its steps; if it be allowable to apply common ideas and expressions to our conceptions of that Great Intelligence which has arranged the plan of the mysterious ladder of animal life. The animals we must examine next, on account of their superiority to the rest, are insects. Small as the ant is, it would not be right to let her be preceded by the oyster. LETTER XXXVII. INSECTA. (_Insects._) Before speaking of insects, my dear child, it will be necessary, in the first place, to tell you to what primary division they belong and on what characters this division has been established. And here I find myself in a difficulty. We have been but too learned already, and now we run the risk of becoming still more so, if we commence an attack on the three primary divisions which follow the vertebrates. We shall have to encounter terrible names and tedious details, besides having to take into account a thousand things of which we have not yet spoken. We are going on quietly with the history of the feeding machine which occupies the middle of the body, and learned men never looked in that direction for the establishment of their divisions; between ourselves, it was not accommodating enough. They have fallen back upon the locomotive apparatus (_movement machine_) which affects the body all over, and which they have proclaimed to be the leading feature of the animal organization, without noticing however that it is, after all, but the servant of the other. It is true that the great divisions are more easily established upon this point than the other, because the differences are more decided. It separates what the other unites, and thus it is that nature carries on that beautiful combination which the Germans have so accurately named "_Unity in Variety_" that is to say, she is always at work, as I have already told you, on the same canvas, but always embroidering it with a different pattern. Wait! I have something to promise, if you are very good, and if this history (that of the feeding machine) should have given you a taste for inquiry. I will tell you another time the history of the movement machine, and there the classification of our learned men will come in naturally very well. In the meantime we will do as they do, and just shut our eyes to their divisions, in which the feeding machine can have no interest, because they were established without reference to it. We will content ourselves, then, without further pretension to science, with modestly examining the last transformations of our pet machine in the principal groups of the inferior animals; of which groups I will now tell you the names in their proper order. They are as follows: Insects, Crustaceans, Mollusks, Worms, and Zoophytes. You must take these names on trust; those which you do not understand will be explained in their places. 1. _Insects._--I know not where it was I once read that there are said to be something like a hundred thousand different species of insects; and I verily believe this is not all. Of course we shall not attempt to review the whole of this formidable battalion. Let us take one of those you are most familiar with--the cockchafer, for instance--and examine what goes on in his inside. The history is nearly that of all the others. "Fly away, cockchafer, fly!" says the song; and surely it is a bird that we have here, and a bird which will appear to you even more wonderful than those of which I have already spoken, when you have considered the simplicity, and at the same time the strength, of his organization. His mode of flight is rather lumbering, it is true; he is, in comparison with the large flies, what the ox is to the deer; but when you contrast the weight of his thick body with the delicacy and narrow dimensions of the two membranes which sustain him in the air, you may well ask yourself how those little morsels of wings, thin as gold-beater's skin, can carry such a mass along. In fact, they only accomplish this feat of strength by dint of an excess of activity almost startling to think of. When you run as fast as you can, how many times, think you, do you move your legs in one second? You would be somewhat puzzled to say; and so should I: but I defy you to count ten. Now the bird makes his wing move much oftener when he beats the air with rapid blows as he flies; but even he does not strike a hundred strokes in a second: and what is this to the feats of the cockchafer's wing? It is not hundreds but thousands of times that he flaps his wings in a second; and here let me hint, by-the-by, that when people seriously wish to find out a method of travelling in the air, they will lay aside balloons, of which they can make nothing in their present condition, and will set to work to fabricate machines with wings which shall beat the air as fast as those of the cockchafer. This sounds extravagant, but I have seen an electric pile fixed in a stand with glass feet, which caused a little hammer to beat thousands of times in a second: and surely the hammer could have been made to communicate its movement to a small wing! Forgive me this little castle in the air! The idea came into my head a long while ago, and the cockchafer has just reminded me of it. I will not, however, pursue the subject, neither will I offer to explain the method used for counting the beats of an insect's wing. That would carry us farther than would be desirable. To return to our little animal. I leave you to imagine the enormous amount of strength required for such precipitate motion. We have spoken of the rapid course of the blood in birds during flight: who shall calculate its comparative rate in this fabulously wonderful locomotive, the cockchafer? And if we lift up the cuirass which encases it, what do we behold? Not a single trace of all the complicated circulation-apparatus you have learnt to know so well; neither heart nor veins nor arteries; only a quantity of whitish liquid, equally distributed throughout the whole internal cavity. Not a trace of lungs, nor any apparent means of renovation for this seemingly motionless blood; for blood it is, in spite of its color, or, at any rate, blood in its first stage of formation. It also has its globules--ill-formed, it is true, and altogether in balls--like those found in the chyle with us; which chyle, be it observed, is the same color as the blood of insects, and may also be considered blood in its apprenticeship. By what magic, then, is this raw, imperfectly-formed steward, who seems altogether stationary, enabled to accomplish exploits which would stagger his higher-bred compeers, agile and perfected as they are? Where does he pick up the oxygen necessary for such repeated movements, it being an established fact that no animal can move at all without consuming oxygen, and that the quantity consumed is in proportion to the rate of motion? Look under his wings for an answer. There, all along his body, you will observe a number of small holes, pierced in a line, at regular distances, and furnished with shutters of two kinds. They are the mouths of what are called _tracheæ_, or breathing tubes: and from them branch out a multitude of little canals, which, spreading in endless ramifications through every part of the body, convey to the whole mass of the blood, from all directions, the air which makes its way into them through the tracheal holes. In this case, you see, it is not the blood which seeks the air, but the air which seeks the blood; whence arises a new system of circulation, whose action is all the more energetic because it is unintermitting, and makes itself felt everywhere at the same time. A little while ago we were wondering at the twofold respiration of birds; yet this is far less surprising than the universally-diffused respiration of insects, who may well be able to do without lungs, seeing that their whole body is one vast lung in itself. For the rest, do not trust to appearances, nor imagine that the blood of our friend the cockchafer in reality remains motionless around the air-tubes, idly drinking in the oxygen which is brought to it. Though not flowing in enclosed canals, it is not the less continually displaced by regular currents, which sweep through and renew this apparently stagnant pool. Nor is this the only instance of such a current presented to us by nature. Guess, however, if you can, where you will have to look for the counterpart to the circulation of the cockchafer. In ocean itself! But, remember, nothing is absolutely little or great in nature, who applies her laws indifferently to a world as to an atom. The blood of our world is water, which contains in itself all the germs of fertility, and without which, as I have already told you, life is impossible either in the animal or vegetable kingdom. The water of brooks, streams, and rivers, flows along in channels, which, when figured in a map, present to the eye of the beholder an exact picture of the system of circulation found in the vertebrated animals. But the waters of the sea are borne along, like the blood of insects, by a secret circulation, which cannot be represented on the map; _i.e._ by immense currents everlastingly in action, some on the surface, some in the mid-heart of the ocean, which drive it in ceaseless course from the equator to the poles, from the poles to the equator; so that the Supreme Intelligence, in His overruling providence, has ordained the same law to set in movement the immensity of ocean, and to effect circulation in the cockchafer's few drops of blood. In the latter we find the moving agent to be a long tube, which runs the whole length of the back, and is called the dorsal vessel (from the Latin _dorsum_, back). I told you that the cockchafer had no heart under his cuirass, but I spoke too hastily. The dorsal vessel is a _true heart_, but a heart devoid of veins or arteries, and thrown into the midst of the blood. It dilates and contracts like ours, sucks in the blood by means of side-valves, which act as our own do, and drives it back again into the mass by that valve at its extremities, which opens near the head. From thence arises a continued to-and-fro movement, which sends the blood from the head to the tail, and brings it back again from the tail to the head. But who would recognise, in this simple primitive organisation, where all seems to go on of its own accord, as it were, the same machine, with all its complicated movements, that we have been so long considering? Well, in this apparently universal shipwreck of all the organs we know so well, there is yet one which survives, and remains the same as ever, namely, the digestive tube. I began by saying the insect is a bird. His digestive tube is formed upon the same pattern as that of birds, so that naturalists have bestowed the same names on the various parts in each of them. After the oesophagus comes a crop (_jabot_), very distinctly indicated; then a gizzard with thick coats, in which the food is ground down. The hen, if you remember, swallows small pebbles, which perform in her gizzard the office of the teeth in our mouths. The cockchafer has no need to swallow anything. His gizzard is furnished with little pieces of horn; real teeth, fixed in their places, which have a great advantage over the chance teeth picked up at random by the hen. I pointed out to you in birds, between the crop and the gizzard, a swelling or enlargement of the digestive tube, pitted with small holes, where the food is moistened by juices. The same enlargement is found here, covered all over with a multitude of small tubes, which might easily be mistaken for hairs, from which also falls a perfect shower of juices. The only difference is, that it comes after the gizzard, instead of before it, as in birds. Some naturalists, considering that the manufacture of chyle takes place here, have called it the _chylific ventricle;_ [Footnote: The corresponding protuberance of the birds bears a name, somewhat similar, but stillmore barbarous. I had passed it over in silence, because, I make the confession in all humility, I do not understand it; but a remorse now seizes me: it is called the _Ventricule succenturie._] a somewhat barbarous name, but one which explains itself, and might with truth be applied to the _duodenum_ of the higher animals. Bile is poured in close to the hinder end of it, but you must not look for the liver; it has disappeared, or rather its form is entirely changed. You remember what the _pancreas_ had become in fishes; _i.e._ a row of tubes giving out a _salivary fluid._ Such is exactly the appearance of the liver in the cockchafer. Instead of that fleshy substance on which hitherto the office of preparing the bile had devolved, you see nothing but a floating bundle of long loose tubes, which, opening into the intestines, pour in their bile. The organ is transformed, but we recognise it again by the office it performs, which continues the same. As to the _pancreas_ it is wanting here, as in the fish with salivary glands; but in its place in many insects other tubes, acting also as glands, pour saliva into the _pharynx; i. e._, the cavity at the back of the throat. As you see, therefore, everything is found complete in this tube of a few inches long; and you can also distinguish there a small and a large intestine. We are speaking of the cockchafer, which feeds on the leaves of trees; and it is for this reason I name some inches as the length of the digestive tube. This would not be longer than the body itself, had it been destined, as in the case of many other insects, to receive animal food. In fact, the law which we have shown to exist with regard to the ox and the lion, rules also over the insect-world; and whilst a radical change seems to have been made in the rest of the organisation, here everything is in its place, and we find ourselves in the same system. Was I not justified in asserting that the unity of the animal plan is to be found in the digestive tube? and that this is the unchanging basis upon which the Creator of the animal world had raised his varied constructions? How would it be, then, if we were to take the insect from its starting-point when it is only a worm, that is to say, merely and simply a digestive tube? for I am only telling you a small portion of its history here; a history you must know, which reveals a miracle still more wonderful than the transformation of the little tadpole into the frog! There is a brilliant-colored fly which comes buzzing about the meat-safe--the bluebottle--do you know her? It is on her account that we put large covers of iron wire over the dishes of meat; but, perhaps, you never troubled yourself to think why. But the truth is, she only comes there to deposit her eggs in the good roast-meat; and if she could get near enough to do so, you would soon afterwards see it swarming with little white worms, which would entirely take away all your appetite. These worms are only flies out at nurse, and they will find their wings by-and-by if you only give them time enough. Disgusting as they may appear on a dining-table, I assure you they deserve more interest than you may think. When we come to speak of worms, we will ask of them to let out the secret of the mysterious transformations of animals. In the meantime, let us finish the observations we were making on the _perfect insect_, as this little creature is called when he has passed through the intermediate stages which separate him from the undeveloped condition. Forgive me, my dear child, here I am speaking to you as if you were a grown-up woman! This is because it is so difficult to explain things of this sort in any other way. And now that you have been introduced into the midst of the wonders of creation, you ought to familiarise yourself with the ideas and terms they have suggested to mankind. I began with you as a child, and great would be my triumph if I could leave you a grown-up girl! And I flatter myself that I have so far set your brain, to work, under pretence of amusing you, that this hope is not altogether unfounded. I found it necessary to say this to you in confidence, because I have just read over our first conversations, and perceive that I have insensibly put you on a different diet from the one I began with. I am obliged to comfort myself by remembering that you have grown older since, and that you are now acquainted with a great many things which you had never heard spoken of then. And this is the secret of all transformations. We crept on at first over ground that was quite unknown to us; but as we went along, our wings must have begun to grow, and we are now able to fly a little! Do not be afraid, however; I will exercise your tiny butterfly-wings very carefully just at present. We have only to examine what becomes of the _chyle_ of the cockchafer after it has been prepared in the pretty little tube so finely wrought. We men have _chyliferous_ vessels which draw up chyle from the intestines and throw it within a short distance of the heart, into the torrent of blood, where its education is completed. But the cockchafer, who has no other vessels than his air-pipes, and the _dorsal tube_, which has no communication with the intestines, what is he to do? Do not distress yourself about him. Make a tube of a bit of linen, well sewn together, and fill it with water. Sew it together as firmly as you may on all sides, the water will have no difficulty in escaping through the meshes. And this is just what happens with the little tubes found in animals, the coats of which are formed of interwoven fibres. By-the-by, from thence comes their name of "_tissue_," which they share in common with all the solid substances of the body, for all were once supposed to have the same general structure. The intestine of the cockchafer floats, did I not say? in the lake of blood which fills the whole cavity of the body. Well, then, the chyle has only to penetrate through these coats, to go where it is wanted. Hence it is not at all surprising that this blood should be white; and I have very good reasons just now for comparing it to our _chyle_. It is, indeed, chyle arriving directly from the place of its manufacture, without undergoing any other process; by which you may see that this little machine (of the digestive organs of the cockchafer), though differing in appearance so entirely from our own, is reducible to the same elements of construction, and that life is maintained by the same process as with us; namely, by the action of the air upon the albumen extracted from food. The cockchafer, it is true, is much further removed from being a fellow-creature of ours than even the horse; but the principle of life is the same with him as with us. And this is quite enough to cause children, who can feel and reason, to think twice before they begin to torture, by way of amusement, a creature whose life the God of goodness has subjected to the same conditions as our own. I speak this to those miserable little executioners who make toys of suffering animals: but the case is different with agriculturists, who have necessarily to contend with the devourers of their harvests, and whom, I admit, it would not be reasonable to bind down by the maxim of Uncle Toby. [Footnote: I have introduced my Uncle Toby, who really has nothing to do here, in order to make you acquainted with a few lines of Sterne, which I wish I could place before the eyes of every child in the world. "Go!" said he, one day at table, to an enormous fly which had been buzzing around his nose and had cruelly tormented him all dinner time. After many attempts, he finally caught him in his hand. "Go! I will not do thee any harm," said my Uncle Toby, rising and crossing the room with the fly in his hand; "I would not hurt a hair of your head. Go!" said he, opening the window and his hand at the same moment, to let the fly escape; "go, poor little devil; away with you; why should I do you any harm? the world is certainly large enough to contain both of us!"] But now to finish with the cockchafer. We have got to examine one very important part of his body, that which in other animals has been the one most talked about ever since we began our study: I mean the mouth. You know that this is the essentially variable point in the digestive tube; so that you will not be much surprised, should we find he has something altogether new. The mouth of the cockchafer is composed of a great number of small pieces placed externally round the entrance to the _alimentary canal_; but the names of these, as they would not interest you, I will not enter upon with you; more especially as they refer to such tiny morsels, that you would have great difficulty in finding them again on the owner. Of these pieces only two are worth our attention. These are two bits of extremely hard horn, placed one on each side of the animal, which are called "_mandibles_" and which serve the cockchafer to cut up the leaves which he eats. Fancy your share of teeth being two huge things fixed in the two corners of your mouth, each advancing alone against the other till they meet under the nose! You would then attack your tarts with the weapons of the cockchafer! You would not, however, be able to bite them straight through from the top to the bottom, as is done by all the animals whom we have yet seen. It is this which so peculiarly distinguishes the insect's manner of feeding; for we have already been taught by the bird and the tortoise, that it is possible to eat with two pieces of horn. The cockchafer now shows us how to eat sideways; but this is merely an accessory detail. It does not affect what happens after the mouthful is swallowed. All insects, however, have not this peculiarity. The cockchafer belongs to the category of grinding insects as they are called, who bite their food: but there is the category of the sucking insects (or suckers), whose food consists of liquids; and these insects are furnished in a different manner. In the innocent butterfly, who lives on the juice of flowers, the digestive tube terminates externally in a sort of _trunk,_ twisted in several convolutions, which is nothing more than an exaggerated elongation of the two jaws, which become hollow within, and form a tube when joined together. When the insect alights on a flower, he suddenly unrolls this trunk, and sucks in the juices from the depth of its "corolla," as you would drink up liquid with a straw from the bottom of a small vial. Amuse yourself some summer's day by watching a butterfly in his labors amongst the flowers: sometimes he stops still, but oftener he is contented to hover over them; and, as he does so, you will see a little loose thread, as it were, move backwards and forwards as fast as possible: this is his trunk, which he darts out, while flying, into the corolla of the flowers, but which scarcely seems to touch them, so delicate is its approach. Less inoffensive far is the trunk of the mosquito-gnat, and of all the detestable troop of blood-sucking flies. It is always a tube; but this tube is no longer a simple straw, but a sheath furnished with stilettos of such exquisite delicacy and temper, that nothing is comparable to them; and these, as they play up and down, pierce the skin of the victim, like the lancets of the lamprey, and, like them, draw in blood as they retreat. Finally, amongst the _parasites,_ the last and lowest group of insects, the stiletto-sheath is reduced to the size of a kind of little tube-shaped beak, which, when not in use, folds down like the fangs of the rattlesnake. You do not know, perhaps, what a parasite is. The word comes from the Greek, and signifies literally, "_that which moves round the corn._" The Greeks applied it to those shameless paupers who, to escape honest labor, made their way into the houses of the great, and enjoyed themselves at their expense. These parasites are little animals which settle themselves on large ones, to suck in, without having worked for it, the blood which the others have manufactured. The wolf hunts, fights, and tears its victim in pieces; and then, by means of that interior labor which I have spent so much time in describing, transforms it into nourishing liquid: and when all this is accomplished, the little flea, who lives hidden among his hairs, coolly draws out for his own use the valuable blood obtained with so much effort. There are many parasites in the world, my dear child--yourself, for instance, to begin with--who are perfectly happy to chew your bread without asking where the corn comes from which made it. But you have heart enough to see plainly that this indifference ought not to last, and that it is not honorable to go on living in this indefinite manner at other people's cost only. You will some day have duties to fulfil, which you should accustom yourself to think of now, in order that you may prepare yourself for them beforehand, so that it may never hereafter be said of you that you passed through the midst of human society, taking from it all you needed, without giving it back anything in return, I advise you to conjure up this idea when the time comes to leave off playing and begin preparing to be of use. The sort of thing is not always very amusing, I admit, but you must look upon it as the ladder by which you will be enabled to rise from the degradation of a parasitical life. If you were in a well, and some one were to let down a real ladder for you to get up by, I do not think you would complain of the difficulty of using it. It is for you, then, to consider whether you would like to remain for ever in your present condition; for those who learn nothing, who _submit_ to nothing, who are good for nothing, but to show off and amuse themselves--these remain parasites all their lives in reality, however little they may sometimes seem to suspect it. At your age, however, there is still no disgrace in the matter. God shows us by the insects that little things are allowed to be parasitical; but on this subject I must return to a point in the history of animals which I touched upon before. I told you, in speaking of the crocodile, that the perfect state of the inferior animals is found represented in the infancy or less perfect state of those above them: and I may say the same again with regard to insects. All the young of the mammalia begin life as parasites, at least, as sucking animals: for they all live at first on their mother's milk, which is nothing more than blood in a peculiar state. But the name of parasite among insects is generally confined to those which take up their abode on the bodies of their hosts; though in common justice it might equally well be applied to the gnat and his relations, who, when once full, make their bow and are off, like the kitten when he has finished sucking. Well, without meaning to find fault, if we descend to the lower ranks of the mammals, we shall find among them many parasites in the received sense of the word. You remember the pouch to which the marsupials owe their odd name. The young kangaroo remains hidden for months in the pouch of its mother, feeding continually all the time; and it is then a strict parasite. During the four following months it goes in and out, and strolls about between meals, like other young ones of its class, and is then an animal at nurse affording thus a twofold example of the tendency of the great Creator to repeat Himself in His conceptions, here using for the infancy of the mammal the system invented for adult insects--elsewhere repeating the butterfly in the humming-bird, who may fairly be called a vertebrated butterfly, and reproducing the gnat in the vampire-bat, which I look upon as an enlarged and perfected revise of the original pattern, whence comes the scourge of our sweet summer nights. And now, surely, I have said enough about these parasites, whose very name, I suspect, will make you shudder after my impertinent application of it. Never mind: it depends entirely upon yourself to get rid of whatever you find humiliating in the position I have hinted at. Do all you can to bring happiness to the parents on whom you live at present, and who give their life-blood so willingly for your good. God has made you very different from those little animals who have neither heart nor reason to guide them. Do not be like them, then, in conduct. By a little obedience and love--child as you are--you can pay them back what you owe, and they will never complain of the bargain. LETTER XXXVIII. CRUSTACEA--MOLLUSCA. (_Crustaceans and Mollusks._) _Crustaceans._ Crustaceans consist of cray-fish, crabs, lobsters, and prawns, who may be considered cousins-german of insects, among which more than one naturalist has thought they ought to be placed. Like them they are divided into _grinders_, having the same action of the mandibles; and _suckers_, who are also parasites, and have tubular sheaths containing stilettos. Mammals and birds are the victims of parasitical insects; fishes have been reserved for the crustaceans, who do not disdain also to fasten upon their humble neighbors, the mollusks; and even among themselves the little ones settle down on the great. A few live on land, but an immense majority in water, and seem destined to represent, in the aquatic world, the aerial class of insects, from whom, however, they differ in many ways. The first difference is in that stony crust with which they are enveloped, like the cockchafer in his horny cuirass, and which you must know well enough if you have ever eaten lobster. Wherever we meet with horn in insects, we find stone in crustaceans. The jaws are stony, and the teeth of the stomach also. They are constructed on the same plan, only the materials are changed. The digestive tube is less complicated, and consists merely of one large stomach, instead of that series of stomachs by which insects approach the organisation of birds. On the other hand, if among some of them the liver is reduced to simple tubes, floating loosely in the body, as we have just seen it in the cockchafer among insects, these tubes are generally so profusely multiplied, and press so closely against each other, that they form a large compact lump--a true liver, to sum up all--from which issues, as from ours, a _choledochian canal_, a bile duct, _i. e._, which passes out into the intestine at the entrance of the pylorus. You recollect that canal of the liver which I was afraid to tell you the name of because it was so ugly? Well, this is that formidable name! Now that you have swallowed so many others, you must be strong enough to digest this. No chyliferous vessels have been found in crustaceans, whence one may conclude that the chyle leaves the intestine by oozing from it, just as it does in insects. There it gives rise to an almost transparent sort of blood, a kind of sap, or lymph, which is put in motion by a genuine circulation-apparatus; a real heart, with all its canals. This heart has only one ventricle, and only sends blood in one direction, as in the case of fishes; but there is an essential difference between them, which we must point out. The heart of fishes may be called a venous heart, since it only receives venous blood, which passes thence to the gills, while that of crustaceans is an arterial heart. It receives the blood directly it leaves the respiratory organ, and sends it, not into one aorta, but into several arteries, which set out at once, each in its own direction, to nourish the various quarters of the body. This greatly resembles the system of circulation, with which we are already acquainted. The veins only are unsatisfactory. They form a kind of transition between the uncertain currents which convey the blood of insects from one end to the other of the cavity in which these strange organs lie bathed, and the closed canals of the higher animals. But they are not canals, properly speaking. The irregular intervals which separate the organs, more numerous here, are enclosed by membranes, between which the venous blood pours, and naturally the chyle also. The whole thus arrives at certain excavations formed at the place where the legs are jointed on to the body--reservoirs, so to speak--where the real canals come to carry it off and convey it away into the gills. It is, in fact, by means of gills that crustaceans breathe in their character of aquatic animals. These gills are made nearly upon the same model as we have already seen in those of fishes; and although their form and arrangement differ in different species, yet the principle is always the same: they are tufts of leaflets springing from stems, up and down which run two tubes; one which brings the blood from the venous reservoirs, the other which carries it to the heart. Crabs, lobsters, and crayfish, who are the "file-leaders" of the crustacean tribe, have gills enclosed in the body, as fishes have; but the circulation of the water goes in a contrary direction to theirs, as does that of the blood. Instead of entering at the mouth and going out at the sides, as we have seen, it enters at the edge of the bony shell which covers over the body and comes out near the mouth--a merely accidental detail which does not in any way alter the play of the apparatus. All these animals are equally adapted for swimming and for walking, crabs especially, their gills accommodating themselves without difficulty to contact with the outer air, as we have seen among certain fishes; so that one might class them with amphibians. There is even one crab who has acquired the name of _land-crab_, because, although he has got gills, he dies in water, the small amount of air he can get out of it at a time being insufficient for him, and who, therefore, lives constantly on land. It is true that he seeks out damp spots, for his gills would also fail him if they became parched, and, like the fishes who make excursions on dry land, he is provided with an internal reservoir, which is always filled with a certain quantity of water. Some aquatic crustaceans have the labor simplified by external gills, which hang down into the water, sometimes depending from the stomach, sometimes from the legs. In France you sometimes see at a table certain little animals, very like shrimps (_squillæ_), the bases of whose hinder legs are fringed by slender tufts, which are in fact their gills. They find themselves placed there just within reach of the venous blood; for in the body opposite the bases of the legs are little cavities in which it accumulates. Now these gills can only act when under water, and so the squillæ dies as soon as he is removed from that protecting element. For the same reason they cannot be kept long, nor travel far, much to the regret of those who like them and live at some distance from the sea. There are other crustaceans, next-door neighbors of the squilla, whose gills are still more simplified. Here the legs themselves are turned into extremely thin plates, which play the part of gills, and are thus organs for two purposes, serving at the same time to swim and breathe with. We have in our house one little crustacean, the only one I know of who associates with men, and that is the wood-louse. You must know the little grizzly beast, which rolls itself up into a ball whenever it thinks itself in danger, and who would be taken for an insect by anyone who was not taught otherwise. The wood-louse has neither gills hanging down outside, nor anything inside her body which resembles the breathing apparatus of her great relations. But, on examining her closely, you will perceive all along her stomach a series of little plates, which are her breathing-organs, and which come under the class of gills, because, like other gills, they require a certain degree of moisture to make them act properly. You will never, therefore, see a wood-louse strutting about in the sunshine, where he would dry up far too quickly; but if ever you get into a dark, damp corner, there you have every chance of finding one. Animals who breathe through their legs and through their stomachs! You are astonished, and ask, What are we coming to? What would you say, then, if I were to go really to the depths of the crustacean world? We should find there such extraordinary beings as you can form no notion of, for they all live down below in the sea, and have no special breathing-organ at all, inasmuch as they breathe through the whole surface of the body. Do not exclaim yet! I will soon show you one whom you know perfectly well, and who has no other way of breathing. But we must keep to the higher crustaceans, if we want to judge of the class. By going too low, we run the risk of not seeing clearly. Animal creation is here on a system of experiments: and they are so endlessly multiplied, and exhibit such a profusion both of deceptive resemblances, and of differences which disappear by transformations, that classification no longer knows which way to turn. Worms, crustaceans, mollusks; to which group do these and those belong? To which ever we like to refer them, for these groups represent nothing definitely determined in the plan of creation; and though easy to be distinguished from each other in the higher branches, they become confused together in the lower, like mountain summits which spring from a common base, at the foot of which they are all united together. On this account, my dear child, you will, I am sure, excuse me now and henceforth, from entering into details of all the horrible beasts which swarm in the shallows of the animal world, and whom learned men have in their wonderful wisdom muffled up in terrible names, in order to prevent children from coming near them! What would you have thought of the poor little squilla, so prettily baptised by the fishermen, if I had taught you that it belonged to the order of _Stomatopoda_? You will scarcely be able to pronounce the word; but that is no fault of mine, it is spelt so. We will content ourselves, then, with having taken a glance at the most clearly marked individuals; and as I said to you just now, it is by them that we will arrange our inventory of the groups. Here, as you may have already remarked, instead of continuing to wander from the original model whose gradual deterioration we have been following all this time from one class to another, it would seem that we are retracing our steps, and regaining some portion of the lost ground. This is because insects, as I have already stated, are an exceptional case--an idea apart from the great general plan--a by-lane turning off from one side of the great line of animal creation. The crustacean, less perfectly worked out than the insect assuredly, but more regular, forms, so to speak, the connecting line between that tiny masterpiece of fancy, so incomplete in its exquisite organisation, and the shapeless but better constituted lump of the mollusk, who conceals under his heavy shell the sacred deposit of real organs, those which we expect to find always and everywhere. An insect outside, though less refined it is true, a mollusk within, the crustacean reminds me of what among us is called an _amateur_--that mild lover of the arts who holds a middle place, as it were, between the artist and the common citizen. I regret that you are not at present quite able to appreciate my comparison fully: but put it by, in reserve, if possible, in your memory; you will find out hereafter how just it is, and it will, perhaps, help to prevent you from always setting the lively, noisy artist, above the quiet and silent citizen. Let this, however, be between you and me. If they could hear us talking, neither artist nor citizen would forgive me, and the amateur still less. _Mollusks._ There is one mollusk universally well known--namely, the oyster--so we will choose him for discussion. To look on one's plate at that little mass of soft, compact substance, one feels inclined to ask what there can possibly be in common between it and us; and if you were to declare that there was not the faintest trace of resemblance between the organization of the oyster and our own, I should not be surprised. Wiser people than you have been caught tripping there; not that they were ignorant of the points in which the oyster resembled us, but they paid no attention to them. Viewing it in other respects, they declared that it was of a structure completely different to our own; and that, in the construction of this machine, the Creator had worked upon a particular plan, laid aside afterwards as useless for any other purpose. I should like to get hold of one of those Academicians, with thirty-six plans, and confound him before you, in proof of his relationship to the oyster, by showing you at one sitting that there is an oyster in himself; nay, further, that he is nothing but an oyster, revised, amended, and considerably enlarged. And do not imagine that I am only using a figure of speech here, as the professors of rhetoric call it; which would be in bad taste: I am speaking literally, and to prove the existence of the oyster in question in our Academician, I shall only ask permission to perform a slight operation upon him. You exclaim at this; but do not alarm yourself, for it is only an operation on paper, he will not die from it. See now, I cut off his head, his two arms, and his legs; I take out of his body the vertebral column and the ribs; I gently place what remains between two shells; and ... there is my oyster. I willingly admit that it is more carefully elaborated and richer in details than its sisters in the oyster beds; but all the principal organs are to be found in them also, and they positively are beings of a similar construction: you shall judge for yourself. The mouth--for there is a mouth, though one must look closer than the oystermen do to discover it--the mouth is exactly what the gullet (oesophagus) would be in a man whose head had been cut off; that is, a truncated tube. Then comes the stomach, situated in the very midst of the liver; which latter may easily be distinguished, even by the most cursory glance at luncheon, from its dark color. The intestine also goes right through the liver, doubling backwards and forwards several times: and thus the digestive tube supplies itself with bile from the cask (to borrow a commercial expression); and this saves the expense of a bile-duct (choledochian canal), which would be an unnecessary mode of conveyance in this case. The animal lives in water; consequently, instead of lungs he has gills: [Footnote: The land-snail has lungs.] these are those thin, finely-streaked plates which make a fringe at the very edge of the shell. Finally, on leaving the gills the blood is received by an arterial heart, with only one ventricle like that of the crustaceans, in the shape of a small pear, similar to ours, having an auricle, and an aorta, branching out so as to distribute the blood throughout the whole body. And now what do we find here, let me ask you, in this mutilated man, reduced to the soft portions of the trunk, whom I have been imagining? A heart, with its arteries; lungs; a liver; an intestine; a stomach and an oesophagus: that is to say, merely and simply the organs of nutrition. That is all, or very nearly so. As you perceive, then, all the elements of our own feeding-machine lie between the two shells of a mollusk; in a rough state as yet, it is true; incomplete, and unruly; as in the case of the intestine, for instance, which in many of these creatures passes without ceremony through the heart: but even so they are quite sufficiently indicated to prevent their being mistaken. Now this machine, it is in vain to deny it, is the animal itself; but it lives at first, and it is this which dies in it last. The other matter (the locomotive power), important as it may seem to us in higher races, only holds a secondary position in reality: the proof of which is, that here is an animal reduced absolutely to a mere feeding-machine, who still lives, whilst there yet remains to be found one who has nothing left but his movement-machine, and who can yet exist. We cannot disown this primitive animal, for we have it within ourselves; lost, so to speak, in the midst of the accessory organs which are successively added to it in proportion as we rise in the animal scale, but still preserving its own life, its personality, if I may use the expression. Listen to this, for here is a history well worth hearing. I will explain to you, hereafter, how all the actions of the movement-machine are performed by means of a network of nervous threads (filaments), whose centre of impulsion is in the brain. How our will acts upon the brain, and gives its orders to the muscles through the nervous fibres, I will not offer to explain: it is a fact, let that suffice us. You say to your foot, "Forward!" and off it starts; "Halt!" and it stops. Here is an organ under command, a servant of the brain, where we rule ourselves: with or without explanation, no one will ever dispute this. The oyster, who has neither head nor brain, has, as his only instrument of action, certain little masses of nervous substance scattered right and left, which are called _ganglions_. These communicate with each other and with the organs by nervous cords, which are interlaced in all directions, without having any common centre, and which give the impetus to all parts of the animal. Well, the human oyster presents to us exactly the same nervous organisation. It has its ganglions and its nerves to itself, which are put into communication with the brain by some threads strayed among his own, but which are not under its orders, and which treat with it on equal terms. You remember, perhaps, the little republic talked about when we first entered the digestive tube; you have now the explanation of it. This republic is the original animal; it is the feeding-machine. I cannot describe it, and the kingdom of which you are queen, better than by comparing them to two States having diplomatic relations with each other, who exchange dispatches and reciprocal influences; and as to the importance of these respective influences, if one were to compare them I scarcely know to which side the balance could incline. We shall return elsewhere to this detail, one of the most interesting of our organisation, and which here finds its natural explanation. For the present I will content myself with reminding you that, since the earliest days of human civilisation, all philosophers, all poets, and all moralists, whether sacred or profane, have borne witness to that double life within us, that inward being, blind and deaf, whose disordered impulses so often carry trouble into those higher regions where will and reason sit enthroned. Behold him taken in his lair at last, this mysterious being. I have just unveiled his origin to you. And here, dear child, I must shelter myself behind a profession of faith. There will not be wanting people to tell you that it is degrading man far too much to look so low for the sources of his organisation, and that this sentence--_the human oyster_--which expresses my idea so well, is neither more nor less than blasphemy. Let them talk, but adopt their opinion only when they have proved to you that man had a special Creator, and that the oyster came from a different hand from ourselves. I should like to know with what face we could venture to complain, poor worms that we are, because it has seemed good to our common Father to carry forward in us his previous creations, and in what respect human dignity would suffer from this contact with a being who, like us, is one of the works of God. That human pride may suffer thereby, I admit, and I am glad it should; but if God has included all creation in His love, we may well include it all in our respect. Whence comes our superiority at all, but from the gratuitous gifts of Him who has made us what we are? Is it to lose it, then, to find ourselves side by side with inferiors whom the Divine benevolence has visited like ourselves? Surely not. But enough of the oyster, who has never, that I am aware of, heard such strange discussions sounding in his ears before. I have no time nor courage now to speak of the other mollusks, who offer more or less the same system of organs which I have just described. I must hasten on to the Worms, who give us the last clue to the great enigma of the animal machine. LETTER XXXIX. VERMES--ZOOPHYTA. (_Worms and Zoophytes_). _Worms._ The worm of worms, the one you know best, is the earthworm: so he shall have the honor of representing his group. He will not take much time to describe. He is, in brief, a tube, open at both ends, so as to allow food to come in and go out. That is all. I talked to you before about the ruminants, those food-manufacturers who are employed in cooking victuals for the stomach, and in disengaging albumen from the coarse materials among which it is apparently lost, so as to give it out again in a more acceptable form. The ruminant has other workmen under him, whom I keep in store for you as the last of the eaters, and who prepare the raw material for him*. These are the vegetables, who seek out the elements of albumen in earth, water, and air, those final sources of all alimentation. The earthworm also is a _preparer_, but in a peculiar way. Look along the garden-walks in summer-time, after rainy weather: you will see here and there, little heaps of earth moulded into small sticks, like dough which has been passed through a tube. [Footnote: M. Mace's account of the earthworm's life seems founded on the assumption that it extracts its nourishment from the earth itself, i.e., from inorganic matter, as _vegetables_ do, to use his own words. But this notion is so entirely at variance with present received opinions, and also with the fact that the animal possesses a gizzard for digesting, as well as an intestinal canal, that it has been necessary to make considerable alterations in the description. To dismiss his theory of the primitive animal, etc., altogether, was, however, impossible, without omitting the whole chapter; but as young heads are not likely to trouble themselves about it, and it is very innocent in itself, it will do no harm; subject to this warning, that M. Macé has taken the earthworm for a more simply organised creature than it really is.--TR.] This is the damp soil which the worm has passed through his tube, after extracting from it, during its passage, the various elements of fertility he requires for the support of his life. This is what makes him so particularly fond of garden soil, because it is richer in animal and vegetable matter than common earth, and proves therefore more nourishing food. The worm, then, feeds on the fat of the earth, which he converts into azotic aliment for the use of moles, hens and Chinese. It only figures, it is true, for want of something better, in Chinese cookery, so profusely hospitable for all that; but the hen doats upon it, and you do not despise it yourself when it comes back to you in the form of a chicken's wing, that second transformation of the matter of which the soil of your garden is composed. It is told of certain savage tribes, the victims of constant scarcity, that they swallow little balls of clay in order to keep down their hunger; and during the great famines in India the distracted inhabitants may, we are told, be seen digging up the banks of the rivers to feed on the fertile clay in which the splendid vegetation of their country is developed. This is a desperate trial of that primeval system of alimentation which answers perfectly with the worm, but becomes a cruel mockery in the case of an organisation as exacting as that of man. Let us examine a little more closely, then, this wonderful tube. At first sight one notices, to begin with, that it is composed of perfectly distinct rings, all quite alike. Inside as well as out each of these rings is an exact repetition of the other. They are all formed of circular muscles, enclosed between two coats, which extend from one to the other. A series of ganglions, arranged in the form of a necklace along the whole length of the body, set in motion the muscular system of the rings, each of which possesses its local centre of impulsion. Each feeds itself in its place from the nourishing juices with which it is in contact, the interior coat enjoying the double property of distilling digestive juices and absorbing digested ones. These juices pass through the muscular partition, and proceed to bathe the outer coat, which plays, at the same time, the part of coat and lung, and affords a passage to the air through its soft, damp surface, like that of gills. From all this results a fine red blood, such as we have not met with since we left the reptiles, and which is manufactured in all parts of the body at once. Each of these rings, then, the worm's only organs, is a little eating machine to and for itself, and at the same time a little movement machine also; in fact, a complete animal. Each one could, if necessary, nourish itself and live apart; and this is what he really does. Learn hence, to despise nothing in nature. One tramples an earthworm under foot, and there below one's heel lies a little revealer of secrets, whose organisation throws the most unexpected light upon one of the greatest mysteries in our own life. I said to you before, and I felt at the time that it was rather beyond you, that "each one of our organs is a distinct being, which has its particular nature and special office, its separate life consequently; and our individual life is the sum total of all these lesser lives, independent one of the other, but which nevertheless blend together, by a mysterious combination, into one common life, which is diffused everywhere, but can be apprehended nowhere in particular." The study of the worm admirably explains this out-of-the-way sentence. And here observe my adjective--my out-of-the-way--for it is a case in point. We may call it a literary worm; a worm of four rings, each perfect in itself, but yet compounded together into a whole with its own idea. That which makes this idea of life most difficult to comprehend is, that one cannot prove it by a direct experiment, since there is not one of our organs which could exist separately from the others. Although independent in their special action, yet these multiplied lives are nevertheless in a state of absolute and mutual dependence, from the imperative need they have of each other to make them act, each having for its share only one particular function, the effect of which extends to all the others. This is called the division of labor; and if you still do not understand me clearly, I will explain it in another way. The heart sends to all the organs--does it not?--the blood, without which they could not live: separated from the heart, the lungs would die immediately. It is to the lungs the blood goes to find the air, without which it could not maintain life. Separated from the lungs, the heart would die immediately. There is nothing belonging to us which can avoid the inexorable requirements of blood and air; consequently, there is nothing which can live an isolated life. I will borrow a simile from human society which you will understand at once. In civilised countries, where division of labor is established, the tailor makes clothes, the mason makes houses, and the baker makes bread. If you could throw them each alone by himself into a wood, the mason would not be able to dress himself, the baker would sleep in the open air, and the tailor would not know how to make bread. Or rather, as not one of them can carry on his trade without the co-operation of a multitude of hands, they could none of them do anything at all. Each completely independent in his work, yet each dependent upon the others, both for living, and even for being able to work, our workmen can only act when they remain bound in close union with the vast society of which they form a part; and our organs--those other laborers whom you have seen working for so long--our organs are just in the same predicament. But in the primitive societies, among savage tribes, where each man can make his clothes, his house, his bread (when he has any), and everything else for himself, you might take such an individual if you liked, and separate him from the rest of the tribe, and he would go on living as before. And so with the rings of the worm, that primitive society of organs. Each of them is a universal workman, who knows how to make everything. Separate him from his fellows, it will not disturb him at all, and he will go on living as if nothing was thematter. I still remember some profound reflections I indulged in one day some years ago whilst leaning on my spade and looking at a worm that I had just cut in two, and whose two halves were walking off one on each side. "There was only one creature here just now," I said to myself, "and now there are two! Have I had power, then, to create one with a stroke of the spade?" I had not then got hold of the key which I now give you, and to which no possible objection can be raised. If there are two beings after the stroke of the spade it is because there were two before. Nay, there were even many more, if we may trust to the "Manual of Zoology" by Milne Edwards, a very good book, excellent for an old scholar like myself, and which I have found very useful in my country-home, as it has enabled me to relate to you one after another the mysterious wonders of life. He says that, "if one cuts an earthworm across into two, three, ten, or even twenty morsels, each of these morsels will go on living in the same way as the whole, and will form a new individual." Twenty! that seems to me a great many, because, as far as I can trust to my brief observations as a gardener, it is necessary that some of the rings should remain united together and afford each other mutual support, in order to succeed in repairing the bleeding breaches; but I would much rather believe it than try the operation. My mind is easy when I am defending the plants that I have sown in my garden from the gluttonous worm who would rob them of their food; but it would not be so if I were cutting them up on my table to learn something about them. Besides, there is no need of an operation to convince oneself of the particular life of each ring. There is one worm, well known by name at least, though happily not to be met with every day, and that is the tape-worm, who establishes himself in the intestine of man, and lives on the chyme, as the other worm does on garden-mould. They call him the _Solitary_ worm in France; and if ever one might suppose a creature appropriately named, it would surely be him; for certainly there is not much society to be looked for in the dwelling he chooses for himself! But it happens that this pretended _solitary_ worm, with his unlimited chain of rings, is only a long row of perfectly distinct beings, so distinct indeed that, from time to time, some of the rings let themselves go, fall off like ripe fruit, and go away to live elsewhere, ready to become the nucleus of a new set, if a happy accident carries them into another intestine, the only place favorable to their development. At last, then, here is a corner of the curtain raised; here we see the associated organs which constitute an animal, living for once a life positively and in all respects their own. We are now satisfied about this; and when at another time we find them bound together in the chains of a union too ingenious to be severed with impunity--which we shall discover by seeing their action stop at the moment of separation--we shall know the cause. Do not think, my dear child, that a wretched earthworm can prove nothing as regards other creatures. The worm is the starting-point of all the organisations which come after him. Of what is he composed? Of a tubewhich is itself composed of rings. Well, it is upon this very tube that the whole animal machine has been founded: and these rings, as they expand and modify themselves in a thousand different ways, give birth to all those varieties of being which drive classifiers to despair, because they will not understand that there ought only to be one animal, since there is only one Creator of animals. Now, this animal is a digestive tube served by organs; it is a worm, _i.e.,_ which goes on constantly embellishing itself. I said to you long ago, and at a time when you scarcely knew anything, "Have you ever observed a worm or a leech in motion? You see a successive swelling up of the whole surface of its body as the creature gradually pushes forward, as if there was something in its inside rolling along from the tail to the head. Such is precisely the appearance which the oesophagus would present to you as the food passes down it, if you had the opportunity of seeing it in action; and this has been called the _vermicular_ movement, in consequence of its resemblance to the movement of a worm." And afterwards, in speaking of the intestine: "If your body were made of glass, so that you could look through it to watch the intestine at work, it would appear to you like an enormous worm, coiled up into a bundle, heaving and moving with all its rings at once." You have now got hold of the secret, namely, that from the beginning to the end of the digestive tube, its movements are those of a worm. What a wonder! and that the worm is a digestive tube which can walk. This worm, or this tube, whichever you please to call it, has never ceased crawling under our eyes since we began this study. Lost sight of in man in the midst of the riches he has picked up on his road, invisible and coiled backward and forward in his palace like an Eastern despot who leaves everything to be done by his slaves; behold him here in his first stage naked, shivering in the air, forced to go off himself and alone to his pasture--ground! But in the coarse earth with which he fills himself I can already see the delicate chyme which his numerous servants will prepare for him later on, and into which the heart-tree will one day send down its roots--the chyliferous vessels. A short time ago I called the oyster the primitive animal, but I was in too great a hurry. The worm is the real primitive animal. He is to be found in the oyster, as the oyster is to be found in us; and that poor little beast is, by comparison, an animal of high pretension, who would be shocked, I am sure, if he could understand what we are saying, and heard us assert that he is nothing but an embellished worm. _Zoophytes._ Two centuries ago it was believed that below the worm, animal life, properly so called, ceased, and the creatures whom I am about to introduce you to were supposed to be animated plants rather than living organisms. Hence their name was especially chosen to express that double nature by which they were thought to have a share in two kingdoms at one time--viz., the animal and vegetable--_zoon_ in Greek meaning animal, and _phuton_ a plant. Zoophytes were set down as animal plants. And although later discoveries have long ago established the fact of the complete animality of zoophytes, the old name is still in general use. But you must not let it deceive you. Zoophytes are animals every inch of them, however low in the organic scale, and although many of the compound ones imitate the growth of plants and shrubs so exactly in their mode of spreading that it is only by the closest observation we can persuade ourselves they do not belong to the vegetable kingdom. Of these there are the delicate buff-colored, prettily-branched, horny specimens found on the shore, which make so beautiful a variety in seaweed pictures among the red and green colors of the real seaweed; but of these also are those wonderful stony shrubs which grow on the submerged rocks of islands in warm seas, and the material which you know so well by the name of coral--the very coral of which the necklaces and bracelets in the jeweller's window are composed. In all cases of compound zoophytes, however, there is one great point which they have in common with the worm, viz., that there is an association of distinct lives acting unanimously; or, rather, to the same end. Plainly as this is seen in the worm, it is still more obvious in the zoophyte. There is no need here either of cutting them up yourself or of taking other people's dissecting operations upon trust. It is enough to use your eyes, with the help, it is true, now and then, of the microscope's clearer sight. You know the old oak-tree which stands on the outskirts of the wood, and is called among the country folk _the patriarch_? Now, this is clearly not an individual, but a nation. It is not a tree; it is a forest. Nay, may I not call it a green field? For this trunk, so truly venerable from ages of growth that one feels inclined to bow to it as one goes by, is, in fact, a collection of structures, accumulated by countless generations of fleeting herbs, _i.e.,_ leaves, not one of which has lived for the space of a whole year round. Every spring some thousands and thousands of buds open to the sun; each one, therefore, affording a passage to a little green point; and this point is an oak, who comes into the world, like the first oak, the grandfather who formerly came forth from an acorn, under the form of an herb or tender leaf, which a sheep might have browsed upon. Yet it is so thoroughly an oak, that you have only to take out the bud carefully before it has expanded and fasten it into another one's place upon a tree of the same family, though of a different species, and it will produce an oak of the same sort as its old companions, and which will, as it progresses, look quite a stranger among the indigenous branches. This is the secret of what the gardeners call _grafting_, and I advise you to try the operation upon rose-trees, for nothing is more amusing. When the autumnal frosts set in, all these troops of new little oaks die, and deliver up their leaves to the wind; but they leave behind, as their summer's work, a tiny morsel of new wood, upon which, if you look carefully, you will see a fresh bud dawning--the hope of the coming season. And thus the great life of the tree is perpetuated from century to century by an uninterrupted succession of transient lives, reminding one in all respects of the life of a nation; and the similitude is complete in the evergreen trees, where the new leaf makes its appearance before the old one has quitted the stem. And such is the life of the great stone trees and shrubs of various kinds which grow under tropical seas, and whose makers and inhabitants are the coral polyps, the undoubted heads of the Zoophyte race. But before considering the _polypidom,_ or external dwelling (otherwise called the _coeneciun,_ or "common house"), you must learn something of its originator, the little _polyp,_ who lives inside, and belongs to a family so widely spread over the face of the earth, that there are scarcely any waters, whether salt or fresh, without them. In your own neighborhood, if you know how to look for them, are to be found on the banks of ponds, or along the borders of streams which lie sleeping in roadside ditches, extraordinary beings which, a hundred years and more ago, completely bewildered the good Dutch naturalist Trembley, who had taken it into his head to study them. Picture to yourself some very tiny bags made of a kind of jelly; gray, brown, or, most commonly of all, green in color, always transparent, and fastened by their base to the stalks of _carex,_ water-lentils, or the confervas, which grow in still water. A hunter on the watch, this bag shoots out on all sides a number of slender threads, like so many whip-lashes, arranged within a circle round the edge of its opening or mouth; and with these whip-lashes all the animalcules which come within reach are entwined, stifled, and carried away to the ever-yawning little gulf, where they are digested in less than no time. Whatever will not digest comes out afterwards by the way it went in. Of what becomes of the results of this digestion it is impossible to form an idea. Were you to cut up the bag and put little morsels of it under the best microscope possible, you would see positively nothing but solid jelly, without the least sign of any organisation whatever. But this is not all. Replace these morsels in the water, and come back tolook at them at the end of five, twenty, or thirty hours. Each one of them will have become a perfect bag, ready to multiply itself afresh if you submit it to the same operation. Sometimes, on some part of the original bag, there suddenly appears a little raised spot, like that which came on your baby brother's arm the other day after he had been vaccinated. What would you have said, if this ugly spot had grown larger and larger without stopping; if it had assumed legs, arms, and a head, and so become another baby, growing from the arm of the first one? Yet this is just what the spots do which come on the bag I have been telling you of; and people have come across bags of a larger species still--between one and two inches in size, in fact--which in this way carried twelve young ones on their backs, if one is allowed to talk of stomachs having _backs_. You perceive at once that this commencement of animal life is not even a digestive tube, and that nothing in it can be found but a stomach, opening straight to the air above and closed up below. It was Réaumur, the originator of the famous thermometer, who gave a name to the wonderful bags discovered by Trembley. Aristotle had previously bestowed the title of _polypus_ (many feet) upon a mollusk outwardly formed upon a similar model [Footnote: This is the cuttle-fish, called _polypus_ by old naturalists. We shall speak of it fully hereafter in the history of the movement machine.] with large whips disposed regularly in a circle round the mouth, and intended for a similar use, only that they have another function besides; that of carrying the body along in the capacity of feet by clinging on to the rocks with their suckers as they go. Réaumur transferred this name to the newcomers, and called them fresh-water polyps, to the infinite amusement of Voltaire, who had declared that they were only blades of grass; a new proof, among many others, that in natural history all the intellect in the world is not worth a pair of good eyes. But it was soon found out that, in collecting these bits of living jelly near the Hague, Trembley had laid his hands on little beings of immense importance on the surface of the globe, and that he had discovered under his microscope the explanation of a mystery which had spread itself, setting human science at defiance, over some thousands of square miles. I talked to you just now of the jeweller's coral, of which ornaments so becoming to dark-haired people are made. That is one of the stony polypidoms I spoke of as stone trees found at the bottom of the sea, where it grows attached to the rocks in the form of a charming little shrub, stretching its red branches in all directions. The Greeks, who were never at a loss, relate that Perseus one day laid down upon the sea-shore the famous head of Medusa, the sight of which had the property of turning everything to stone, and that the nymphs, in sport, showed it to the coral shrubs; a fact which explained everything quite naturally. Without exactly holding this mythological explanation, modern philosophers had not got much farther, and coral was still a puzzle to them, which they were not fond of troubling themselves about; till, roused by Trembley's revelations, they examined it more carefully, and discovered in its soft extremities (hitherto unnoticed) those same living jelly-bags or sacs, with their circlets of legs, or rather arms, charged with supplying them with food. These were marine polyps, which grow, like those in fresh water, one upon another, but each in its own crusty cell; and like the buds of the oak, these buds of the stony tree form each its special deposit, which it bequeaths in dying to the general mass. In short, as the tender shoot of the oak is filled by degrees with the wood which forms within it, and hardens into a branch, that goes on increasing by perpetually new growths, so the jelly polyp of the polypidom hardens below into stone and dies incessantly at the base, while it lives on indefinitely above in its constantly-renewed summit. Do not get tired of all this phantasmagoria, my dear pupil: it is a matter of the highest interest. Here is the point of junction--the bond, as it were, between the three kingdoms: an animal growing vegetable-wise produces a mineral mass, extracted from the waters of the sea by an infinity of little living crucibles, who carry on under our eyes the work begun in the first ages of the globe, and quietly manufacture continents for the use of future generations. This ought to console you, my dear child, for being little. It is by little things that God loves to effect what is truly great. He did not seek out the elephant or the whale to form these worlds; He chose workmen no bigger than a pin's head. I have spoken to you about jeweller's coral, which is made into toys or presents for ladies to adorn themselves with; but its brethren, the madrepores of the Pacific Ocean play a very different part. They have formed in front of the shores of New Holland a barrier of reefs three hundred leagues in extent and twenty wide. What are all our buildings after this?--those pyramids and cathedrals which seem so gigantic to us? This ever-increasing wave of coral polypidoms will one day shut against navigators the entrance to one part of the sea's tropical region; and lands not to be found on the map to-day will then lie stretched out under the sun, covered with plants and animals; and this in places where ships now plough the ocean. Know, also, that a great portion of the soil which we tread under foot has no other origin. It was manufactured formerly in the sea by infinite myriads of beings, often infinitely small. Each one, whether polype or shell, produced its grain of stone, and from all these grains God, who directed their work, has made our country. But it is time to bring this chattering to a close, for it will never end if I do not force myself to stop. I leave it with regret; but all these paths through which I have threaded my way one after another without counting them, have already made a volume which may possibly be considered too large for you. There are many other zoophytes besides the coral polypes, and all of them beautiful and curious. They all inhabit the fertile depths of the waters where God has deposited the first germs of life. I cannot describe them to you now. But to make amends, I will give you a piece of advice which will perhaps make some people stare. Ask your papa to lend you Michelet's book, _The Sea_, and look there for what is said about the mysterious animals which lie hid beneath the waves. His book was not written for you as this one is: and if, in spite of all my good intentions, I have not always succeeded in being as comprehensible as I meant to be, Michelet, who never thought about little people when he took up his pen, will certainly startle you now and then. But do not be disheartened by a word. You will find there, that which will be forever plain to you, the poesy of nature, and children comprehend that better than learned men. LETTER XL. THE NOURISHMENT OF PLANTS. One more word before we part about the last of the eaters, about Vegetables. They will furnish you with a new and very clearly marked proof of the uniformity of the fundamental conditions to which the Author of life has subjected all organised beings. Let us look once more at this oak, of whose manner of growth I was obliged to give you a sketch beforehand, in order to show you the ties which unite it with its immediate neighbors in the animal kingdom. How does it feed? I need not tell you this. It feeds by its roots, which suck up in the bosom of the earth the water charged with the juices which form its nourishment. Are you aware that every large branch had its subterranean fellow or representative, and that the annual shoot at the top of the tree is reproduced at the base by fresh fibres, which extend themselves in the soil of the earth, in proportion as their sisters above make their way in the air? And thus, by means of organs ever young, the life and progress of the great association is kept up, while those members whose day of work is over still remain there as the supports of the edifice. It is the same with human societies. They are sustained by what is old, but they live and progress only by what is young. The sap, then, which is the name given to the moisture or water sucked in by the young roots, having once got into the cells of which the tissue of the fibres is composed, passes from one to another, and travels thus to the top of the tree, where it is wanted by the leaves. There is no obvious machinery here, however, to impel it forward. It journeys on of itself, as it were, under the action of laws which have never been satisfactorily explained, but all of which are dependent on the vital force or life-power of the tree, inasmuch as without it there is no circulation. One agent, but by no means the principal, or it would act as well in a dead tree as a living one, is _capillary attraction_; and, if you wish to know what that is, you have only to think of what happens to a towel, if you hang it upon a peg, and leave the end of it soaking in water. Does not the "wet" seem to climb up it thread by thread, till it is damp from one end to the other? A little in this way--but these similes are very imperfect, and will not bear close application--the sap rises in a tree, stealing up branch by branch; and it is then called _ascending sap_. [Footnote: M. Macé speaks of this sap as the _blood of the tree_, and of the leaves only as _lungs_. These statements have been modified so as to meet the fact that _ascending sap_ consists of, and conveys the raw elements of _food_ to, the leaves; that in the leaves this food is _digested_, as well as brought in contact with the air, and that it is thus converted into that nourishing fluid, the _descending sap_, which certainly plays the part of steward to the tree as our blood does to us, and therefore may now be called the blood of the tree. It must be remembered, however, that each tree has its own sort of steward, as the case of the _Euphorbia_ (quoted afterwards) plainly shows. The analogy with the more general substance of blood is therefore not very complete.-TR.] It arrives at last at the leaves, which it enters as our food enters our stomachs, and for the same purpose; for in them takes place, as in all true stomachs, that process of digestion by which the elements of the crude sap-food are decomposed from their first condition, and converted into a nourishing chyle; in each tree of a sort "after its kind." But more than this. Like the outer coat of the earthworm, the coat of the leaf affords a passage to air and moisture through its surface; and here, therefore, takes place that mysterious exchange which is everywhere the essential condition of life. Here is the charcoal-market as before, only the bargainers have changed parts. The air, which in the other case received the _carbon,_ delivers it up, now, and receives oxygen in exchange; exactly the reverse of its traffic with animals. In other words, the tree inhales through its leaves the carbonic acid gas thrown into the atmosphere by our lungs. On its own responsibility it breaks through the alliance between the carbon and oxygen contracted in our organs; keeps the carbon for its own use, to restore it to us another day under the form of wood, or, by the aid of the charcoal-burner, in the pure and simple state of charcoal; and sets at liberty the oxygen, which once more goes off in search of new lungs and a fresh alliance. Thus a constant equilibrium is maintained in the atmosphere; and thus, by a system of perpetual rotation or everlasting merry-go-round, the same substances serve, indefinitely, to support life of every opposite description. Now there are two things to be remembered in this inverted respiration of vegetables. In the first place, it occurs only in the parts which are _green_. Flowers, fruit, the root, and every part of any other color, do as we do when we breathe; _i.e._ deprive the air of its oxygen, charging it with carbonic acid instead. For which reason, by-the-by, we ought not to keep flowers in a bedroom at night. Charming as they are, they are _poisoners_, and a headache is what we may fairly expect after sleeping shut in with them in the same room. It is almost as bad to allow green boughs to remain there either, for, in the dark, even the green parts cease to purify the air, and begin like the others to manufacture carbonic acid, at the expense of course of their carbon, which thus by degrees is used up. Now, as it is the carbon which constitutes the solid fibres of plants and produces their green color, they soon become yellow and limp when deprived of light. You may, perhaps, have wondered why the gardener amused himself with smothering his poor lettuces by tying them up at top like a knot of "back hair," instead of letting them grow freely in the air and sunshine. It is, my dear, to make them more tender and delicate for you to eat; and those beautiful, crisp, yellow leaves, so delicious to the tooth, would have been green and tough, had they not slowly and quietly let out a great portion of their store of carbon in darkness during the last few days, before being gathered. Even without playing the gardener, you may assure yourself of this fact in a still more simple manner. Put a flat board upon the lawn and leave it there for three days; then take it up again, and you will find just where the board has prevented the light from reaching the grass, a yellow mark so distinctly traced as to be seen from the other end of the garden. But to return to the sap, which we left undergoing a change from air and solar influences in the leaves. The ascending sap was to all appearance only clear water. When it returns from the leaves, charged with carbon, it is a thick juice having almost the consistency, and sometimes even the color of milk, and is possessed of properties altogether new. The most striking example that I can give you of thedifference of the two states of sap is the Euphorbia of the Canary Islands, whose digestive or descending sap is a violent poison. When the natives of the country are accidentally pressed by thirst, they carefully remove the bark in which the fatal juice circulates, and are then able to refresh themselves safely by sucking the stem, which yields only the watery sap sucked from the ground, and as yet unaltered and harmless. Each of these two saps, in fact, has its path distinctly traced for it: the first rises through the wood, the second descends through the bark, whence it is called descending sap. If you wish to satisfy yourself of this, fasten a rather tight knot of pack-thread round a young branch, and after a time you will see it pine below the knot and become swollen above it, an unanswerable proof that the nutritive juices flowed downward through the bark; for the wood inside the branch will have been uninjured by the strangling pressure. Remember this, my dear, when you are playing in the garden, and do not injure the bark of the young trees your father likes so much to see flourishing. It is by the bark that they are nourished, and you might even kill them by treating it too roughly. And now I must show you how the nutrition is carried on, or, if you like better, how the tree grows by means of this descending sap. See: here is a fir tree, which has just been cut down to the ground. Now, if you like, I will tell you in a moment how old it is. I will even tell you the age of every branch, little and big ones both, without making a mistake in a single year; and you know as well as I do that I am no conjuror. You see these small circles so delicately drawn, as it were, upon the face of the sawn trunk, each wider than the last, as if they were composed of a set of tubes, of unequal sizes, fitting exactly into each other. Now count them; and you will perhaps find twenty-five; and as each of these circles represents the work of one year, you will know that the tree is twenty-five years old. In spring, when the sap begins to move more briskly, it deposits everywhere between the wood and the bark, from the trunk to the farthest boughs of the tree, a uniform layer of a thick liquid, which moulds itself exactly upon the wood already formed. This layer stiffens during the year; it gets filled with the carbon left in it atom after atom, by each drop of the descending sap as it goes by, and thus insensibly becoming organised and hardened. When winter arrives to interrupt the work, it will have formed two _ligneous, i.e._ woody layers, as they are called. Of these, one belongs to the wood, and will never move again so long as the tree lasts, for it will be covered over, and as it were buried, by the successive layers yet to come; while, on the contrary, the other (layer) belongs to the bark, and is doomed to find itself perpetually forced outwards by the fresh layers, which will after a while insinuate themselves between it and the wood. It is for this reason that the bark of old trunks of trees is so deeply furrowed, and that the dry scales may be picked off the surface without the slightest injury to the tree. It is part of the original bark, dead long ago. The old wood also is dead inside, and even when it is altogether gone, the glad youthful branches growing green in the sunshine will scarcely find it out! This accounts for those oaks which time has hollowed without destroying, as those of Allonville in Normandy, in which mass is said, and which is moreover the greenest tree in the country. But without going so far, who has not seen those hollow old willows, sometimes pierced with holes letting in daylight, yet proudly crowned above by a forest of young boughs, as green and full of vigor as if the trunk were still in its prime? What was dead has departed, but all that has life in it remains, and that is enough for the tree. Need I add that the descending sap, this steward of the vegetable, has also his workmen to supply with materials, as in our case, and that he is always falling in on his road with organs, all of which want different things from him? That here a flower has to be formed, there a fruit, there a leaf, or a bit of wood, and so on: and that a mysterious intelligence--the same that we have found everywhere else--presides over all these varied constructions, the materials for which are mixed together pell-mell, in the imperceptible thread of sap which oozes from the leaf to the bark? I recollect just as I am about to conclude, my dear child, that I once told you, you were a small temple in which God perpetually attests His presence, by a permanent miracle. You may now henceforth look upon a tree as something more than a bit of wood, yielding a pleasant shade. God is in it also. CONCLUSION. And now, my dear little pupil, to what conclusion do we come from all this? To that which I announced to you from the first. Throughout the length and breadth of creation, from the highest to the lowest grade, every living thing is subject to the same law. Everything eats, and eats nearly in the same manner, since everywhere the same substances furnish the feast. I laid down in my first letter that our feeding machine was reproduced even to the farthest limits of the animal kingdom, though always becoming more simple as the species descends in the scale. And afterwards, where we began the study of animals, I told you that in this machine lay the uniformity of their construction. Was I not right? and what could I add to all the proofs which have developed themselves one after another, to establish the fact of this uniformity of plan in the animal machine, in all its essential points? And it will be to the lasting renown of the illustrious Geoffroy St. Hilaire that it was, in the face of all the Academies and under the fire of very learned indignation, he proclaimed this truth, which one cannot lose sight of without losing one's way in a crowd of arbitrary fancies. I return, then, to the definition which I gave you in speaking of the worm, and which is the final word of the ideas I have been endeavoring to make you understand. _An animal is a digestive tube served by organs._ In the first place it must eat, and for this therefore the Creator provided first. All the rest came afterwards in order to enable it to eat more readily, to secure its prey more easily, and to make the most of it when eaten. The movement machine, therefore, whose history I have promised you, is only an assistant, and not the principal feature of the organisation, and it is not by it, therefore, that the question can be decided, whether God has made three, four, or five animals, or whether he has only made one. And now, my dear little pupil, I will bid you adieu, or rather say as the French do, "Au revoir," which means "Good-bye till we meet again," begging you to excuse any awkward expressions that may have escaped me, as also my having now and then talked about things because they have interested me, without perhaps sufficiently considering whether they might have an equal interest for you. Yet, while the pen is still in my hand, I will not leave you my concluding definition of an animal without adding a word of explanation. You know nothing about such matters yourself, but to some people my words might have the air of a parody upon another definition, applied by those grave gentlemen the Philosophers to man, whom they have denominated _An intelligence served by organs_. My definition is applicable only to the animal, and not to man, observe. Man in the natural, physical machinery of his body, is very decidedly an animal; yet as certainly is he, by the divine reflection which shines within him, something much more and greater; but _what_, is so far beyond the reach of definitionthat I shall not attempt to give you one. "Man," as Jesus Christ has said, "lives not by bread alone, but by every word that proccedeth out of the mouth of God." What it is that is nourished in us by that word, is precisely what I cannot attempt to define for you; yet I think you have understood my meaning. Go, then, and eat your food in peace, like the pretty little animal that you are; but do not forget to nourish also the other part of your being; that indeed which is of the most importance, and which enables you to ascend to your Creator. THE END. POSTSCRIPT. In going through the preceding pages (Part II) with a comparative anatomist, it became evident that some few popular and other errors and misconceptions had crept into this portion of M. Macé's usually clear and accurate work. Naturally it was not in his power to verify all the statements he had to make on so many and such varied subjects, and he appears occasionally to have trusted to works of old-fashioned or doubtful authority. In these cases I have considered it desirable to make such corrections as should secure the trustworthiness of the descriptions as far as they pretend to go. It would not, however, have been in my power to accomplish this, but for the kind and efficient aid I have received from a scientific student of these subjects; and I am glad of this opportunity of acknowledging how much I am indebted to him for his assistance in making the necessary alterations, as well as for confirming the correctness of the greater portion of the work. MARGARET GATTY. January, 1865. January, 1865. 
6986	----	[Illustration] PATHFINDER PHYSIOLOGY No. 3 HYGIENIC PHYSIOLOGY WITH SPECIAL REFERENCE TO THE USE OF ALCOHOLIC DRINKS AND NARCOTICS BEING A REVISED EDITION OF THE FOURTEEN WEEKS IN HUMAN PHYSIOLOGY BY JOEL DORMAN STEELE, PH.D. ENLARGED EDITION WITH SELECTED READINGS _Edited for the use of Schools, in accordance with the recent Legislation upon Temperance Instruction_ INDORSEMENT. BOSTON, _June_ 20, 1889. The Pathfinder Series of Text-books on Anatomy, Physiology, and Hygiene consists of the following volumes: I. Child's Health Primer (for Primary Grades). II. Hygiene for Young People or, Young People's Physiology. (for Intermediate Classes) III. Hygienic Physiology (for Advanced Pupils). The above are the series originally prepared (as their general title indicates) to supply the demand created by the laws for temperance instruction in public schools in the United States. They were written by experts under the supervision of the Scientific Department of the National Woman's Christian Temperance Union, published by the instigation of the same, and have been carefully revised from time to time, under the same supervision, to keep them abreast with the latest teachings of science. Being both teachable and well adapted to grade, their educational value, as proven by schoolroom tests, is of the highest order. We therefore cordially indorse and highly recommend the Pathfinder Series for use in schools. MARY H. HUNT, _National and International Superintendent of the Scientific Dep't of the Woman's Christian Temperance Union; Life Director of the National Educational Association._ ADVISORY BOARD: JOSEPH COOK, WILLIAM E. SHELDON, ALBERT H. PLUMB, D.D., DANIEL DORCHESTER, D.D. PREFACE The term Physiology, or the science of the functions of the body, has come to include Anatomy, or the science of its structure, and Hygiene, or the laws of health; the one being essential to the proper understanding of physiology, and the other being its practical application to life. The three are intimately blended, and in treating of the different subjects the author has drawn no line of distinction where nature has made none. This work is not prepared for the use of medical students, but for the instruction of youth in the principles which underlie the preservation of health and the formation of correct physical habits. All else is made subservient to this practical knowledge. A simple scientific dress is used which, while conducing to clearness, also gratifies that general desire of children to know something of the nomenclature of any study they pursue. To the description of each organ is appended an account of its most common diseases, accidents, etc., and, when practicable, their mode of treatment. A pupil may thus learn, for example, the cause and cure of "a cold," the management of a wound, or the nature of an inflammation. The Practical Questions, which have been a prominent feature in other books of the series, will be found, it is hoped, equally useful in this work. Directions for preparing simple microscopic objects, and illustrations of the different organs, are given under each subject. The Readings, which represent the ideas but not always the exact phraseology of the author quoted, have, in general, been selected with direct reference to Practical Hygiene, a subject which now largely occupies the public mind. The dangers that lurk in foul air and contaminated water, in bad drainage, leaky gas pipes, and defective plumbing, in reckless appetites, and in careless dissemination of contagious diseases, are here portrayed in such a manner as, it is trusted, will assist the pupil to avoid these treacherous quicksands, and to provide for himself a solid path of health. Under the heading of Health and Disease will be found Hints about the sick room, Directions for the use of Disinfectants, Suggestions as to what to do "Till the Doctor comes," and a list of antidotes for Poisons. Questions for Class Use, a full Glossary, and an ample Index complete the book. Believing in a Divine Architect of the human form, the author can not refrain from occasionally pointing out His inimitable workmanship, and impressing the lesson of a Great Final Cause. The author has gleaned from every field, at home and abroad, to secure that which would interest and profit his pupils. In general, Flint's great work on the "Physiology of Man," an undisputed authority on both sides of the Atlantic, has been adopted as the standard in digestion, respiration, circulation, and the nervous system. Leidy's "Human Anatomy," and Sappey's "Traité d'Anatomie" have been followed on all anatomical questions, and have furnished many beautiful drawings. Huxley's "Physiology" has afforded exceedingly valuable aid. Foster's "Text-Book of Physiology," Hinton's "Health and its Conditions," Black's "Ten Laws of Health," Williams's practical essay on "Our Eyes and How to Use them," Le Pileur's charming treatise on "The Wonders of the Human Body," and that quaint volume, "Odd Hours of a Physician," have aided the author with facts and fancies. The writings of Draper, Dalton, Carpenter, Yalentin, Mapother, Watson, Lankester, Letheby, Hall, Hamilton, Bell, Wilson, Bower, Cutter, Hutchison, Wood, Bigelow, Stille, Holmes, Beigel, and others have been freely consulted. PUBLISHERS' NOTE. An ABRIDGED EDITION of this work is published, to afford a cheaper manual --adapted to Junior Classes and Common Schools. The abridgment contains the essence of this text, nearly all its illustrations, and the whole of the Temperance matter as here presented. ORDER "HYGIENIC PHYSIOLOGY, ABRIDGED." READING REFERENCES. Foster's "Text-Book of Physiology"; Leidy's "Human Anatomy"; Draper's "Human Physiology"; Dalton's "Physiology and Hygiene"; Cutter's "Physiology"; Johnston and Church's "Chemistry of Common Life"; Letheby's "Food"; Tyndall "On Light," and "On Sound"; Mint's "Physiology of Man "; Rosenthal's "Physiology of the Muscles and Nerves"; Bernstein's "Five Senses of Man"; Huxley and Youmans's "Physiology and Hygiene"; Sappey's "Traité d'Anatomie "; Luys's "Brain and its Functions"; Smith's "Foods"; Bain's "Mind and Body"; Pettigrew's "Animal Locomotion"; Carpenter's "Human Physiology," and "Mental Physiology"; Wilder and Gage's "Anatomy"; Jarvis's "Physiology and Laws of Health." Hargreaves's "Alcohol and Science"; Richardson's "Ten Lectures on Alcohol," and "Diseases of Modern Life"; Brown's "Alcohol"; Davis's "Intemperance and Crime"; Pitman's "Alcohol and the State"; "Anti- Tobacco"; Howie's "Stimulants and Narcotics"; Hunt's "Alcohol as Food or Medicine"; Schützenberger's "Fermentation"; Hubbard's "Opium Habit and Alcoholism"; Trouessart's "Microbes, Ferments, and Molds." CONTENTS INTRODUCTION I.--THE SKELETON THE HEAD THE TRUNK THE LIMBS II.--THE MUSCLES III.--THE SKIN THE HAIR AND THE NAILS THE TEETH IV.--RESPIRATION AND THE VOICE V.--THE CIRCULATION THE BLOOD THE HEART THE ARTERIES THE VEINS VI.--DIGESTION AND FOOD VII.--THE NERVOUS SYSTEM THE BRAIN THE SPINAL CORD AND THE NERVES THE SYMPATHETIC SYSTEM VIII.--THE SPECIAL SENSES TOUCH TASTE SMELL HEARING SIGHT IX.--HEALTH AND DISEASE.--DEATH AND DECAY 1. HINTS ABOUT THE SICK ROOM 2. DISINFECTANTS 3. WHAT TO DO "TILL THE DOCTOR COMES" 4. ANTIDOTES TO POISONS X.--SELECTED READINGS XI.--APPENDIX QUESTIONS FOR CLASS USE GLOSSARY INDEX SUGGESTIONS To Teachers Seeing is believing--more than that, it is often knowing and remembering. The mere reading of a statement is of little value compared with the observation of a fact. Every opportunity should therefore be taken of exhibiting to the pupil the phenomena described, and thus making them real. A microscope is so essential to the understanding of many subjects, that it is indispensable to the proper teaching of Physiology. A suitable instrument and carefully prepared specimens, showing the structure of the bones, the skin, and the blood of various animals, the pigment cells of the eye, etc., may be obtained at a small cost from any good optician. On naming the subject of a paragraph, the pupil should be prepared to tell all he knows about it. No failure should discourage the teacher in establishing this mode of study and recitation. A little practice will produce the most satisfactory results. The unexpected question and the apt reply develop a certain sharpness and readiness which are worthy of cultivation. The questions for review, or any others that the wit of the teacher may suggest, can be effectively used to break the monotony of a topical recitation, thereby securing the benefits of both systems. The pupil should expect to be questioned each day upon any subject passed over during the term, and thus the entire knowledge gained will be within his grasp for instant use. While some are reciting to the teacher, let others write on slates or on the blackboard. At the close of the recitation, let all criticise the ideas, the spelling, the use of capitals, the pronunciation, the grammar, and the mode of expression. Greater accuracy and much collateral drill may thus be secured at little expense of valuable school time. The Introduction is designed merely to furnish suggestive material for the first lesson, preparatory to beginning the study. Other subjects for consideration may be found in the section on Health and Disease, in the Selected Readings, and among the questions given in the Appendix. Where time will allow, the Selected Readings may profitably be used in connection with the topics to which they relate. Questions upon them are so incorporated with those upon the text proper that they may be employed or not, according to the judgment of the teacher. NOTE.--Interest in the study of Physiology will be much increased by the use of the microscope and prepared slides. These may be obtained from any good optician. INTRODUCTION. Physiological study in youth is of inestimable value. Precious lives are frequently lost through ignorance. Thousands squander in early years the strength which should have been kept for the work of real life. Habits are often formed in youth which entail weakness and poverty upon manhood, and are a cause of lifelong regret. The use of a strained limb may permanently damage it. Some silly feat of strength may produce an irreparable injury. A thoughtless hour of reading by twilight may impair the sight for life. A terrible accident may happen, and a dear friend perish before our eyes, while we stand by powerless to render the assistance we could so easily give did we "only know what to do." The thousand little hints which may save or lengthen life, may repel or abate disease, and the simple laws which regulate our bodily vigor, should be so familiar that we may be quick to apply them in an emergency. The preservation of health is easier than the cure of disease. Childhood can not afford to wait for the lesson of experience which is learned only when the penalty of violated law has been already incurred, and health irrevocably lost. NATURE'S LAWS INVIOLABLE.--In infancy, we learn how terribly Nature punishes a violation of certain laws, and how promptly she applies the penalty. We soon find out the peril of fire, falls, edged tools, and the like. We fail, however, to notice the equally sharp and certain punishments which bad habits entail. We are quick to feel the need of food, but not so ready to perceive the danger of an excess. A lack of air drives us at once to secure a supply; foul air is as fatal, but it gives us no warning. Nature provides a little training for us at the outset of life, but leaves the most for us to learn by bitter experience. So in youth we throw away our strength as if it were a burden of which we desire to be rid. We eat anything, and at any time; do anything we please, and sit up any number of nights with little or no sleep. Because we feel only a momentary discomfort from these physical sins, we fondly imagine when that is gone we are all right again. Our drafts upon our constitution are promptly paid, and we expect this will always be the case; but some day they will come back to us, protested; Nature will refuse to meet our demands, and we shall find ourselves physical bankrupts. We are furnished in the beginning with a certain vital force upon which we may draw. We can be spendthrifts and waste it in youth, or be wise and so husband it till manhood. Our shortcomings are all charged against this stock. Nature's memory never fails; she keeps her account with perfect exactness. Every physical sin subtracts from the sum and strength of our years. We may cure a disease, but it never leaves us as it found us. We may heal a wound, but the scar still shows. We reap as we sow, and we may either gather in the thorns, one by one, to torment and destroy, or we may rejoice in the happy harvest of a hale old age. I. THE SKELETON. "Not in the World of Light alone, Where God has built His blazing throne, Nor yet alone on earth below, With belted seas that come and go, And endless isles of sunlit green Is all thy Maker's glory seen-- Look in upon thy wondrous frame, Eternal wisdom still the same!" HOLMES. ANALYSIS OF THE SKELETON. NOTE.--The following Table of 206 bones is exclusive of the 8 sesamoid bones which occur in pairs at the roots of the thumb and great toe, making 214 as given by Leidy and Draper. Gray omits the bones of the ear, and names 200 as the total number. THE SKELETON. _ | I. THE HEAD (_28 bones._) | _ | | Frontal Bone (forehead). | _ | Two Parietal Bones. | | 1. CRANIUM..............| Two Temporal (temple) Bones. | | (_8 bones._) | Sphenoid Bone. | | | Ethmoid (sieve-like bone at root of nose). | | |_Occipital Bone (back and base of skull). | | _ | | | Two Superior Maxillary (upper jaw) Bones. | | | Inferior Maxillary (lower jaw) Bone. | | | Two Malar (cheek) Bones. | | 2. FACE.................| Two Lachrymal Bones. | | (_14 bones._) | Two Turbinated (scroll like) Bones, each | | | side of nose. | | | Two Nasal Bones (Bridge of nose). | | | Vomer (the bone between the nostrils). | | |_Two Palate Bones. | | _ | | | Hammer. | | 3. EARS.................| Anvil. | |_ (_6 bones._) |_Stirrup. | | II. THE TRUNK (_54 bones._) | _ | | Cervical Vertebræ (seven vertebræ of the | _ | neck). | | 1. SPINAL COLUMN........| Dorsal Vertebræ (twelve vertebræ of the | | | back). | | | Lumbar Vertebræ (five vertebræ of the | | |_ loins). | | _ | | | True Ribs. | | 2. RIBS.................|_False Ribs. | | | | 3. STERNUM (breastbone). | | | | 4. OS HYOIDES (bone at the root of tongue). | | _ | | | Two Innominata. | |_5. PELVIS...............| Sacrum. | |_Coccyx. | | III. THE LIMBS (_124 bones._) | _ | _ | _Clavicle._ | | Shoulder...|__Scapula._ | _ | _ | | 1. UPPER LIMBS..........| | _Humerus._ | | (_64 bones._) | Arm........|__Ulna and Radius._ | | | _ | | | | _Eight Wrist or Carpal | | | | Bones._ | | |_Hand.......| _Five Metacarpal Bones._ | | |__Phalanges (14 bones)._ | | _ | | _ | _Femur._ | | | Leg........| _Patella._ | | | |__Tibia and Fibula._ | | 2. LOWER LIMBS..........| _ | |_ (_60 bones._) | | _Seven Tarsal Bones._ |_ | Foot.......| _Five Metatarsal Bones._ |_ |__Phalanges (14 bones)._ _ | 1. Uses. _ | 2. Composition. | 1. FORM, STRUCTURE, | 3. Structure. | ETC., OF THE BONES | 4. Growth. | | 5. Repair. THE SKELETON | |_6. The Joints. | _ | 2. CLASSIFICATION OF | 1. The Head. |_ THE BONES. | 2. The Trunk. |_3. The Limbs. THE SKELETON. I. FORM, STRUCTURE, ETC., OF THE BONES. (_See page 269_.) THE SKELETON, or framework of the "House we live in," is composed of about 200 bones. [Footnote: The precise number varies in different periods of life. Several which are separated in youth become united in old age. Thus five of the "false vertebræ" at the base of the spine early join in one great bone--the sacrum; while four tiny ones below it often run into a bony mass--the coccyx (Fig. 6); in the child, the sternum is composed of eight pieces, while in the adult it consists of only three. While, however, the number of the bones is uncertain, their relative length is so exact that the length of the entire skeleton, and thence the height of the man, can be obtained by measuring a single one of the principal bones. Fossil bones and those found at Pompeii have the same proportion as our own.] USES AND FORMS OF THE BONES.--They have three principal uses: 1. To protect the delicate organs; [Footnote: An organ is a portion of the body designed for a particular use, called its _function_. Thus the heart circulates the blood; the liver produces the bile.] 2. To serve as levers on which the muscles may act to produce motion; and 3. To preserve the shape of the body. Bones differ in form according to the uses they subserve. For convenience in walking, some are long; for strength and compactness, some are short and thick; for covering a cavity, some are flat; and for special purposes, some are irregular. The general form is such as to combine strength and lightness. For example, all the long bones of the limbs are round and hollow, thus giving with the same weight a greater strength, [Footnote: Cut a sheet of foolscap in two pieces. Roll one half into a compact cylinder, and fold the other into a close, flat strip; support the ends of each and hang weights in the middle until they bend. The superior strength of the roll will astonish one unfamiliar with this mechanical principle. In a rod, the particles break in succession, first those on the outside, and later those in the center. In a tube, the particles are all arranged where they resist the first strain. Iron pillars are therefore cast hollow. Stalks of grass and grain are so light as to bend before a breath of wind, yet are stiff enough to sustain their load of seed. Bone has been found by experiment to possess twice the resisting property of solid oak.] and also a larger surface for the attachment of the muscles. The Composition of the Bones at maturity is about one part animal to two parts mineral matter. The proportion varies with the age. In youth it is nearly half and half, while in old age the mineral is greatly in excess. By soaking a bone in weak muriatic acid, and thus dissolving the mineral matter, its shape will not change, but its stiffness will disappear, leaving a tough, gristly substance [Footnote: Mix a wineglass of muriatic acid with a pint of water, and place in it a sheep's rib. In a day or two, the bone will become so soft that it can be tied into a knot. In the same way, an egg may be made so pliable that it can be crowded into a narrow- necked bottle, within which it will expand, and become an object of great curiosity to the uninitiated. By boiling bones at a high temperature, the animal matter separates in the form of gelatine. Dogs and cats extract the animal matter from the bones they eat. Fossil bones deposited in the ground during the Geologic period, were found by Cuvier to contain considerable animal matter. Gelatine was actually extracted from the Cambridge mastodon, and made into glue. A tolerably nutritious food might thus be manufactured from bones older than man himself.] (cartilage) which can be bent like rubber. If the bone be burned in the fire, thus consuming the animal matter, the shape will still be the same, but it will have lost its tenacity, and the beautiful, pure-white residue [Footnote: From bones thus calcined, the phosphorus of the chemist is made. See Steele's "Popular Chemistry," page 114. If the animal matter be not consumed, but only charred, the bone will be black and brittle. In this way, the "boneblack" of commerce is manufactured.] may be crumbled into powder with the fingers. FIG. 2. [Illustration: _The Thigh Bone, or Femur, sawed lengthwise._] We thus see that a bone receives hardness and rigidity from its mineral, and tenacity and elasticity from its animal matter. The entire bone is at first composed of cartilage, which gradually _ossifies_ or turns to bone. [Footnote: The ossification of the bones on the sides and upper part of the skull, for example, begins by a rounded spot in the middle of each one. From this spot the ossification extends outward in every direction, thus gradually approaching the edges of the bone. When two adjacent bones meet, there will be a line where their edges are in contact with each other, but have not yet united; but when more than two bones meet in this way, there will be an empty space between them at their point of junction. Thus, if you lay down three coins upon the table with their edges touching one another, there will be a three-sided space in the middle between them; if you lay down four coins in the same manner, the space between them will be four-sided. Now at the back part of the head there is a spot where three bones come together in this way, leaving a small, three-sided opening between them: this is called the "posterior fontanelle." On the top of the head, four bones come together, leaving between them a large, four-sided opening: this is called the "anterior fontanelle." These openings are termed the _fontanelles_, because we can feel the pulsations of the brain through them, like the bubbling of water in a fountain. They gradually diminish in size, owing to the growth of the bony parts around them, and are completely closed at the age of four years after birth.--DALTON.] Certain portions near the joints are long delayed in this process, and by their elasticity assist in breaking the shock of a fall. [Footnote: Frogs and toads, which move by jumping, and consequently receive so many jars, retain these unossified portions (epiphyses) nearly through, life, while alligators and turtles whose position is sprawling, and whose motions are measured do not have them at all--LEIDY] Hence the bones of children are tough, are not readily fractured, and when broken easily heal again; [Footnote: This is only one of the many illustrations of the Infinite care that watches over helpless infancy, until knowledge and ability are acquired to meet the perils of life.] while those of elderly people are liable to fracture, and do not quickly unite. FIG. 3. [Illustration: _A thin slice of Bone, highly magnified showing the lacunæ, the tiny tubes (canaliculi) radiating from them, and four Haversian canals, three seen crosswise and one lengthwise._] THE STRUCTURE OF THE BONES--When a bone is sawed lengthwise, it is found to be a compact shell filled with a spongy substance This filling increases in quantity, and becomes more porous at the ends of the bone, thus giving greater size to form a strong joint, while the solid portion increases near the middle, where strength alone is needed. Each fiber of this bulky material diminishes the shock of a sudden blow, and also acts as a beam to brace the exterior wall. The recumbent position of the alligator protects him from falls, and therefore his bones contain very little spongy substance. In the body, bones are not the dry, dead, blanched things they commonly seem to be, but are moist, living, pinkish structures, covered with a tough membrane, called the per-i-os'-te-um [Footnote: The relations of the periosteum to the bone are very interesting. Instances are on record where the bone has been removed, leaving the periosteum, from which the entire bone was afterward renewed.] (_peri_, around, and _osteon_, a bone), while the hollow is filled with marrow, rich in fat, and full of blood vessels. If we examine a thin slice with the microscope, we shall see black spots with lines running in all directions, and looking very like minute insects. These are really little cavities, called la-cu'-næ [Footnote: When the bone is dry, the lacunæ are filled with air, which refracts the light, so that none of it reaches the eye, and hence the cavities appear black.] from which radiate tiny tubes. The lacunæ are arranged in circles around larger tubes, termed from their discoverer, _Haversian canals_, which serve as passages for the blood vessels that nourish the bone. GROWTH OF THE BONES.--By means of this system of canals, the blood circulates as freely through the bones as through any part of the body, The whole structure is constantly but slowly changing, [Footnote: Bone is sometimes produced with surprising rapidity. The great Irish Elk is calculated by Prof. Owen to have cast off and renewed, annually in its antlers eighty pounds of bone.] old material being taken out and new put in. A curious illustration is seen in the fact that if madder be mixed with the food of pigs, it will tinge their bones red. REPAIR OF THE BONES.--When a bone is broken, the blood at once oozes out of the fractured ends. This soon gives place to a watery fluid, which in a fortnight thickens to a gristly substance, strong enough to hold them in place. Bone matter is then slowly deposited, which in five or six weeks will unite the broken parts. Nature, at first, apparently endeavors to remedy the weakness of the material by excess in the quantity, and so the new portion is larger than the old. But the extra matter will be gradually absorbed, sometimes so perfectly as to leave no trace of the injury. (See p. 271.) A broken limb should be held in place by splints, or a plaster cast, to enable this process to go on uninterruptedly, and also lest a sudden jar might rupture the partially mended break. For a long time, the new portion consists largely of animal matter, and so is tender and pliable. The utmost care is therefore necessary to prevent a malformation. THE JOINTS are packed with a soft, smooth cartilage, or gristle, which fits so perfectly as to be airtight. Upon convex surfaces, it is thickest at the middle, and upon concave surfaces, it is thickest at the edge, or where the wear is greatest. In addition, the ends of the bones are covered with a thin membrane, the _synovial_ (_sun_, with; _ovum_, an egg), which secretes a viscid fluid, not unlike the white of an egg. This lubricates the joints, and prevents the noise and wear of friction. The body is the only machine that oils itself. The bones which form the joint are tied with stout ligaments (_ligo_, I bind), or bands, of a smooth, silvery white tissue, [Footnote: The general term _tissue_ is applied to the various textures of which the organs are composed. For example, the osseous tissue forms the bones; the fibrous tissue, the skin, tendons, and ligaments.] so strong that the bones are sometimes broken without injuring the fastenings. II. CLASSIFICATION OF THE BONES. For convenience, the bones of the skeleton are considered in three divisions: the _head_, the _trunk_, and the _limbs_. 1. THE HEAD. THE BONES OF THE SKULL AND THE FACE form a cavity for the protection of the brain and the four organs of sense, viz.: sight, smell, taste, and hearing. All these bones are immovable except the lower jaw, which is hinged [Footnote: A ring of cartilage is inserted in its joints, something after the manner of a washer in machinery. This follows the movements of the jaw, and admits of freer motion, while it guards against dislocation.] at the back so as to allow for the opening and shutting of the mouth. THE SKULL is composed, in general, of two compact plates, with a spongy layer between. These are in several pieces, the outer ones being joined by notched edges, sutures (su'tyurs,), in the way carpenters term dovetailing. (See Fig. 4.) FIG. 4. [Illustration: _The Skull._--1. _frontal bone;_ 2, _parietal bone;_ 3, _temporal bone;_ 4, _the sphenoid bone;_ 5, _ethmoid bone;_ 6, _superior maxillary (upper jaw) bone;_ 7, _malar bone;_ 8, _lachrymal bone;_ 9, _nasal bone;_ 10, _inferior maxillary (lower jaw) bone._] The peculiar structure and form of the skull afford a perfect shelter for the brain--an organ so delicate that, if unprotected, an ordinary blow would destroy it. Its oval or egg shape adapts it to resist pressure. The smaller and stronger end is in front, where the danger is greatest. Projections before and behind shield the less protected parts. The hard plates are not easy to penetrate. [Footnote: Instances have been known where bullets, striking against the skull, have glanced off, been flattened, or even split into halves. In the Peninsular Campaign, the author saw a man who had been struck in the forehead by a bullet which, instead of penetrating the brain, had followed the skull around to the back of the head, and there passed out.] The spongy packing deadens every blow. [Footnote: An experiment resembling the familiar one of the balls in Natural Philosophy ("Steele's Popular Physics," Fig. 6, p. 26), beautifully illustrates this point. Several balls of ivory are suspended by cords, as in Fig. 5. If A be raised and then let fall, it will transmit the force to B, and that to C, and so on until F is reached, which will fly off with the impulse. If now a ball of spongy bone be substituted for an ivory one anywhere in the line, the force will be checked, and the last ball will not stir.] The separate pieces with their curious joinings disperse any jar which one may receive, and also prevent fractures from spreading. FIG. 5. [Illustration] The frequent openings in this strong bone box afford safe avenues for the passage of numerous nerves and vessels which communicate between the brain and the rest of the body. FIG. 6. [Illustration: _The Spine; the seven vertebræ of the neck, cervical; the twelve of the back, dorsal; the five of the loins, lumbar;_ a, _the sacrum, and_ b, _the coccyx, coming the nine "false vertebræ."_ (p. 3).] 2 THE TRUNK. THE TRUNK has two important cavities. The upper part, or _chest_, contains the heart and the lungs, and the lower part, or _abdomen_, holds the stomach, liver, kidneys, and other organs (Fig. 31). The principal bones are those of the _spine_, the _ribs_, and the _hips_. THE SPINE consists of twenty-four bones, between which are placed pads of cartilage. [Footnote: These pads vary in thickness from one fourth to one half an inch. They become condensed by the weight they bear during the day, so that we are somewhat shorter at evening than in the morning. Their elasticity causes them to resume their usual size during the night, or when we lie down for a time.] A canal is hollowed out of the column for the safe passage of the spinal cord. (See Fig. 50.) Projections (processes) at the back and on either side are abundant for the attachment of the muscles. The packing acts as a cushion to prevent any jar from reaching the brain when we jump or run, while the double curve of the spine also tends to disperse the force of a fall. Thus on every side the utmost caution is taken to guard that precious gem in its casket. THE PERFECTION OF THE SPINE surpasses all human contrivances. Its various uses seem a bundle of contradictions. A chain of twenty-four bones is made so stiff that it will bear a heavy burden, and so flexible that it will bend like rubber; yet, all the while, it transmits no shock, and even hides a delicate nerve within that would thrill with the slightest touch. Resting upon it, the brain is borne without a tremor; and, clinging to it, the vital organs are carried without fear of harm. FIG. 7. [Illustration: B, _the first cervical vertebra, the atlas;_ A, _the atlas, and the second cervical vertebra, the axis;_ e, _the odontoid process;_ c, _the foramen._] THE SKULL ARTICULATES with (is jointed to) the spine in a peculiar manner. On the top of the upper vertebra (atlas [Footnote: Thus called because, as, in ancient fable, the god Atlas supported the world on his shoulders, so in the body this bone bears the head.]) are two little hollows (_a_, _b_, Fig. 7), nicely packed and lined with the synovial membrane, into which fit the corresponding projections on the lower part of the skull, and thus the head can rock to and fro. The second vertebra (axis) has a peg, _e_, which projects through a hole, _c_, in the first. FIG. 8. [Illustration: _The Thorax or Chest._ a, _the sternum;_ b _to_ c, _the true ribs;_ d _to_ h, _the false ribs;_ g, h, _the floating ribs;_ i, k, _the dorsal vertebræ._] The surfaces of both vertebræ are so smooth that they easily glide on each other, and thus, when we move the head side wise, the atlas turns around the peg, _e_, of the axis. THE RIBS, also twenty-four in number, are arranged in pairs on each side of the chest. At the back, they are all attached to the spine. In front, the upper seven pairs are tied by cartilages to the breastbone (sternum); three are fastened to each other and to the cartilage above, and two, the floating ribs, are loose. The natural form of the chest is that of a cone diminishing upward. But, owing to the tightness of the clothing commonly worn, the reverse is often the case. The long, slender ribs give lightness, [Footnote: If the chest wall were in one bone thick enough to resist a blow, it would be unwieldy and heavy As it is, the separate bones bound by cartilages yield gradually, and diffuse the force among them all, and so are rarely broken.] the arched form confers strength, and the cartilages impart elasticity,--properties essential to the protection of the delicate organs within, and to freedom of motion in respiration. (See note, p. 80.) FIG. 9. [Illustration: _The Pelvis._ a, _the sacrum;_ b, b, _the right and the left innominatum._] THE HIP BONES, called by anatomists the innominata, or nameless bones, form an irregular basin styled the _pelvis_ (_pelvis_, a basin). In the upper part, is the foot of the spinal column--a wedge-shaped bone termed the _sacrum_ [Footnote: So called because it was anciently offered in sacrifice.] (sacred), firmly planted here between the widespreading and solid bones of the pelvis, like the keystone to an arch, and giving a steady support to the heavy burden above. 3. THE LIMBS. TWO SETS OF LIMBS branch from the trunk, viz.: the upper, and the lower. They closely resemble each other. The arm corresponds to the thigh; the forearm, to the leg; the wrist, to the ankle; the fingers, to the toes. The fingers and the toes are so much alike that they receive the same name, _digits_, while the several bones of both have also the common appellation, _phalanges_. The differences which exist grow out of their varying uses. The foot is characterized by strength; the hand, by mobility. FIG. 10. [Illustration: _The Shoulder Joint._ a, _the clavicle;_ b, _the scapula._] 1. THE UPPER LIMBS.--THE SHOULDER.--The bones of the shoulder are the collar bone (clavicle), and the shoulder blade (scapula). The _clavicle_ (_clavis_, a key) is a long, slender bone, shaped like the Italic _f_. It is fastened at one end to the breastbone and the first rib, and, at the other, to the shoulder blade. (See Fig. 1.) It thus holds the shoulder joint out from the chest, and gives the arm greater play. If it be removed or broken, the head of the arm bone will fall, and the motions of the arm be greatly restricted. [Footnote: Animals which use the forelegs only for support (as the horse, ox, etc.), do not possess this bone. "It is found in those that dig, fly, climb and seize."] THE SHOULDER BLADE is a thin, flat, triangular bone, fitted to the top and back of the chest, and designed to give a foundation for the muscles of the shoulder. THE SHOULDER JOINT.--The arm bone, or _humerus_, articulates with the shoulder blade by a ball-and-socket joint. This consists of a cup-like cavity in the latter bone, and a rounded head in the former, to fit it,-- thus affording a free rotary motion. The shallowness of the socket accounts for the frequent dislocation of this joint, but a deeper one would diminish the easy swing of the arm. FIG. 11. [Illustration: _Bones of the right Forearm._ H, _the humerus;_ R, _the radius; and_ U, _the ulna._] THE ELBOW.--At the elbow, the humerus articulates with the _ulna_--a slender bone on the inner side of the forearm--by a hinge joint which admits of motion in only two directions, _i. e._, backward and forward. The ulna is small at its lower end; the _radius_, or large bone of the forearm, on the contrary, is small at its upper end, while it is large at its lower end, where it forms the wrist joint. At the elbow, the head of the radius is convex and fits into a shallow cavity in the ulna, while at the wrist the ulna plays in a similar socket in the radius. Thus the radius may roll over and even cross the ulna. THE WRIST, or _carpus_, consists of two rows of very irregular bones, one of which articulates with the forearm; the other, with the hand. They are placed side to side, and so firmly fastened as to admit of only a gliding motion. This gives little play, but great strength, elasticity, and power of resisting shocks. THE HAND.--The _metacarpal_ (_meta_, beyond; _karpos_, wrist), or bones of the palm, support each a thumb or a finger. Each finger has three bones, while the thumb has only two. The first bone of the thumb, standing apart from the rest, enjoys a special freedom of motion, and adds greatly to the usefulness of the hand. FIG. 12. [Illustration: _Bones of the Hand and the Wrist._] The first bone (Figs. 11, 12) of each finger is so attached to the corresponding metacarpal bone as to move in several directions upon it, but the other phalanges form hinge joints. The fingers are named in order: the thumb, the index, the middle, the ring, and the little finger. Their different lengths cause them to fit the hollow of the hand when it is closed, and probably enable us more easily to grasp objects of varying size. If the hand clasps a ball, the tips of the fingers will be in a straight line. The hand in its perfection belongs only to man. Its elegance of outline, delicacy of mold, and beauty of color have made it the study of artists; while its exquisite mobility and adaptation as a perfect instrument have led many philosophers to attribute man's superiority even more to the hand than to the mind. [Footnote: How constantly the hand aids us in explaining or enforcing a thought! We affirm a fact by placing the hand as if we would rest it firmly on a body; we deny by a gesture putting the false or erroneous proposition away from us; we express doubt by holding the hand suspended, as if hesitating whether to take or reject. When we part from dear friends, or greet them again after long absence, the hand extends toward them as if to retain, or to bring them sooner to us. If a recital or a proposition is revolting, we reject it energetically in gesture as in thought. In a friendly adieu we wave our good wishes to him who is their object; but when it expresses enmity, by a brusque movement we sever every tie. The open hand is carried backward to express fear or horror, as well as to avoid contact; it goes forward to meet the hand of friendship; it is raised suppliantly in prayer toward Him from whom we hope for help; it caresses lovingly the downy cheek of the infant, and rests on its head invoking the blessing of Heaven,--_Wonders of the Human Body_.] FIG. 13. [Illustration: _The Mechanism of the Hip Joint._] 2. THE LOWER LIMBS.--THE HIP--The thigh bone, or _femur_, is the largest and necessarily the strongest in the skeleton, since at every step it has to bear the weight of the whole body. It articulates with the hip bone by a ball-and-socket joint. Unlike the shoulder joint, the cup here is deep, thus affording less play, but greater strength. It fits so tightly that the pressure of the air largely aids in keeping the bones in place. [Footnote: In order to test this, a hole was bored through a hip bone, so as to admit air into the socket, the thigh bone at once fell out as far as the ligaments would permit. An experiment was also devised whereby a suitably prepared hip joint was placed under the receiver of an air pump. On exhausting the air, the weight of the femur caused it to drop out of the socket, while the readmission of the air raised it to its place. Without this arrangement, the adjacent muscles would have been compelled to bear the additional weight of the thighbone every time it was raised. Now the pressure of the air rids them of this unnecessary burden, and hence they are less easily fatigued--WEBER] Indeed, when the muscles are cut away, great force is required to detach the limbs. THE KNEE is strengthened by the patella_, or kneepan (_patella_, little dish), a chestnut-shaped bone firmly fastened over the joint. The shin bone, or _tibia_, the large, triangular bone on the inner side of the leg, articulates both with the femur and the foot by hinge joints. The kneejoint is so made, however, as to admit of a slight rotary motion when the limb is not extended. The _fibula_ (_fibula_, a clasp), the small, outside bone of the leg, is firmly bound at each end to the tibia. (See Fig. 1.) It is immovable, and, as the tibia bears the principal weight of the body, the chief use of this second bone seems to be to give more surface to which the muscles may be attached. [Footnote: A young man in the hospital at Limoges had lost the middle part of his tibia. The lost bone was not reproduced, but the fibula, the naturally weak and slender part of the leg, became thick and strong enough to support the whole body.--STANLEY'S _Lectures_.] THE FOOT.--The general arrangement of the foot is strikingly like that of the hand (Fig. 1). The several parts are the _tarsus_, the _metatarsus_, and the _phalanges_. The graceful arch of the foot, and the numerous bones joined by cartilages, give an elasticity to the step that could never be attained by a single, flat bone. [Footnote: The foot consists of an arch, the base of which is more extended in front than behind, and the whole weight of the body is made to fall on this arch by means of a variety of joints. These joints further enable the foot to be applied, without inconvenience, to rough and uneven surfaces.--HINTON.] The toes naturally lie straight forward in the line of the foot. Few persons in civilized nations, however, have naturally formed feet. The big toe is crowded upon the others, while crossed toes, nails grown-in, enormous joints, corns, and bunions abound. THE CAUSE OF THESE DEFORMITIES is found in the shape and size of fashionable boots and shoes. The sole ought to be large enough for full play of motion, the uppers should not crowd the toes, and the heels should be low, flat, and broad. As it is, there is a constant warfare between Nature and our shoemakers, [Footnote: When we are measured for boots or shoes, we should stand on a sheet of paper, and have the shoemaker mark with a pencil the exact outline of our feet as they bear our whole weight. When the shoe is made, the sole should exactly cover this outline.] and we are the victims. The narrow point in front pinches our toes, and compels them to override one another; the narrow sole compresses the arch; while the high heel, by throwing all the weight forward on the toes, strains the ankle, and, by sending the pressure where Nature did not design it to fall, causes that joint to become enlarged. The body bends forward to meet the demand of this new motion, and thus loses its uprightness and beauty, making our gait stiff and ungraceful. (See p. 271.) DISEASES, ETC.--l. _Rickets_, a disease of early life, is caused by a lack of mineral matter in the bones, rendering them soft and pliable, so that they bend under the weight of the body. They thus become permanently distorted, and of course are weaker than if they were straight, [Footnote: Just here appears an exceedingly beautiful provision. As soon as the disproportion of animal matter ceases, a larger supply of mineral is sent to the weak points, and the bones actually become thicker, denser, harder, and consequently stronger at the very concave part where the stress of pressure is greatest.--WATSON'S _Lectures_. We shall often have occasion to refer to similar wise and providential arrangements whereby the body is enabled to remedy defects, and to prepare for accidents.] Rickets is most common among children who have inherited a feeble constitution and who are ill fed, or who live in damp, ill-ventilated houses. "Rickety" children should have plenty of fresh air and sunlight, nourishing food, comfortable clothing, and, in short, the best of hygienic care. 2. _A Felon_ is a swelling of the finger or thumb, usually of the last joint. It is marked by an accumulation beneath the periosteum and next the bone. The physician will merely cut through the periosteum, and let out the effete matter. 3. _Bowlegs_ are caused by children standing on their feet before the bones of the lower limbs are strong enough to bear their weight. The custom of encouraging young children to stand by means of a chair or the support of the hand, while the bones are yet soft and pliable, is a cruel one, and liable to produce permanent deformity. Nature will set the child on its feet when the proper time comes. 4. _Curvature of the Spine_.--When the spine is bent, the packing between the vertebræ becomes compressed on one side into a wedge-like shape. After a time, it will lose its elasticity, and the spine will become distorted. This often occurs in the case of students who bend forward to bring their eyes nearer their books, instead of lifting their books nearer their eyes, or who raise their right shoulder above their left when writing at a desk which is too high. Round shoulders, small, weak lungs, and, frequently, diseases of the spine are the consequences. An erect posture in reading or writing conduces not alone to beauty of form, but also to health of body. We shall learn hereafter that the action of the muscles bears an important part in preserving the symmetry of the spine. Muscular strength comes from bodily activity; hence, one of the best preventives of spinal curvature is daily exercise in the open air. 5. _Sprains_ are produced when the ligaments which bind the bones of a joint are strained, twisted, or torn from their attachments. They are quite as serious as a broken bone, and require careful attention lest they lead to a crippling for life. By premature use a sprained limb may be permanently impaired. Hence, the joint should be kept quiet, even after the immediate pain is gone. 6. _A Dislocation_ is the forcible displacement of a bone from its socket. It is, generally, the result of a fall or a violent blow. The tissues of the joint are often ruptured, while the contraction of the muscles prevents the easy return of the bone to its place. A dislocation should be reduced as soon as possible after the injury, before inflammation supervenes. PRACTICAL QUESTIONS. 1. Why does not a fall hurt a child as much as it does a grown person? 2. Should a young child ever be urged to stand or walk? 3. What is meant by "breaking one's neck"? 4. Should chairs or benches have straight backs? 5. Should a child's feet be allowed to dangle from a high seat? 6. Why can we tell whether a fowl is young by pressing on the point of the breastbone? 7. What is the use of the marrow in the bones? 8. Why is the shoulder so often put out of joint? 9. How can you tie a knot in a bone? 10. Why are high pillows injurious? 11. Is a stooping posture a healthful position? 12. Should a boot have a heel piece? 13. Why should one always sit and walk erect? 14. Why does a young child creep rather than walk? 15. What is the natural direction of the big toe? 16. What is the difference between a sprain and a fracture? A dislocation? 17. Does the general health of the system affect the strength of the bones? 18. Is living bone sensitive? _Ans_.--Scrape a bone, and its vessels bleed; cut or bore a bone, and its granulations sprout up; break a bone, and it will heal; cut a piece away, and more bone will readily be produced; hurt it in any way, and it inflames; burn it, and it dies. Take any proof of sensibility but the mere feeling of pain, and it will answer to the proof.--BELL'S _Anatomy_. Animal sensibility would be inconvenient; it is therefore not to be found except in diseased bone, where it sometimes exhibits itself too acutely.--TODD'S _Cyclopedia of Anatomy_. 19. Is the constitution of bone the same in animals as in man? _Ans_.--The bones of quadrupeds do not differ much from those of man. In general they are of a coarser texture, and in some, as in those of the elephant's head, we find extensive air cells.--TODD'S _Anatomy_. II. THE MUSCLES. "Behold the outward moving frame, Its living marbles jointed strong With glistening band and silvery thong, And link'd to reason's guiding reins By myriad rings in trembling chains, Each graven with the threaded zone Which claims it as the Master's own." HOLMES. ANALYSIS OF THE MUSCLES. _ | 1. The Use of the Muscles. | 2. Contractility of the Muscles. _ | 3. Arrangement of the Muscles. | 1. THE USE, STRUCTURE | 4. The two Kinds of Muscles. | AND ACTION OF THE | 5. The Structure of the Muscles. | MUSCLES. | 6. The Tendons for Fastening Muscles. | | 7. The Muscles and Bones as Levers. | | 8. The Effect of Big Joints. | | 9. Action of the Muscles in Walking. | |_10. Action of the Muscles in Walking. | | 2. THE MUSCULAR SENSE. | _ | 3. HYGIENE OF THE | 1. Necessity of Exercise. | MUSCLES. | 2. Time for Exercise. | |_ 3. Kinds of Exercise. | | 4. WONDERS OF THE MUSCLES. | _ | | 1. St. Vitus's Dance. | | 2. Convulstions. | | 3. Locked-jaw. |_5. DISEASES. | 4. Gout. | 5. Rheumatism. | 6. Lumbago. |_ 7. A Ganglion. FIG. 14. [Illustration] THE MUSCLES. THE USE OF THE MUSCLES.--The skeleton is the image of death. Its unsightly appearance instinctively repels us. We have seen, however, what uses it subserves in the body, and how the ugly-looking bones abound in nice contrivances and ingenious workmanship. In life, the framework is hidden by the flesh. This covering is a mass of muscles, which by their arrangement and their properties not only give form and symmetry to the body, but also produce its varied movements. In Fig. 14, we see the large exterior muscles. Beneath these are many others; while deeply hidden within are tiny, delicate ones, too small to be seen with the naked eye. There are, in all, about five hundred, each having its special use, and all working in exquisite harmony and perfection. CONTRACTILITY.--The peculiar property of the muscles is their power of contraction, whereby they decrease in length and increase in thickness. [Footnote: The maximum force of this contraction has been estimated as high as from eighty-five to one hundred and fourteen pounds per square inch.] This may be caused by an effort of the will, by cold, by a sharp blow, etc. It does not cease at death, but, in certain cold-blooded animals, a contraction of the muscles is often noticed long after the head has been cut off. ARRANGEMENT OF THE MUSCLES. [Footnote: "Could we behold properly the muscular fibers in operation, nothing, as a mere mechanical exhibition, can be conceived more superb than the intricate and combined actions that must take place during our most common movements. Look at a person running or leaping, or watch the motions of the eye. How rapid, how delicate, how complicated, and yet how accurate, are the motions required! Think of the endurance of such a muscle as the heart, that can contract, with a force equal to sixty pounds, seventy-five times every minute, for eighty years together, without being weary."]--The muscles are nearly all arranged in pairs, each with its antagonist, so that, as they contract and expand alternately, the bone to which they are attached is moved to and fro. (See p. 275.) If you grasp the arm tightly with your hand just above the elbow joint, and bend the forearm, you will feel the muscle on the inside (biceps, _a_, Fig. 14) swell, and become hard and prominent, while the outside muscle (triceps, _f_) will be relaxed. Now straighten the arm, and the swelling and hardness of the inside muscle will vanish, while the outside one will, in turn, become rigid. So, also, if you clasp the arm just below the elbow, and then open and shut the fingers, you can feel the alternate expanding and relaxing of the muscles on opposite sides of the arms. If the muscles on one side of the face become palsied, those on the other side will draw the mouth that way. Squinting is caused by one of the straight muscles of the eye (Fig. 17) contracting more strongly than its antagonist. KINDS OF MUSCLES.--There are two kinds of muscles, the _voluntary_, which are under the control of our will, and the _involuntary_, which are not. Thus our limbs stiffen or relax as we please, but the heart beats on by day and by night. The eyelid, however, is both voluntary and involuntary, so that while we wink constantly without effort, we can, to a certain extent, restrain or control the motion. STRUCTURE OF THE MUSCLES.--If we take a piece of lean beef and wash out the red color, we can easily detect the fine fibers of which the meat is composed. In boiling corned beef for the table, the fibers often separate, owing to the dissolving of the delicate tissue which bound them together. By means of the microscope, we find that these fibers are made up of minute filaments (_fibrils_), and that each fibril is composed of a row of small cells arranged like a string of beads. This gives the muscles a peculiar striped (striated) appearance. [Footnote: The involuntary muscles consist generally of smooth, fibrous tissue, and form sheets or membranes in the walls of hollow organs. By their contraction they change the size of cavities which they inclose. Some functions, however, like the action of the heart, or the movements of deglutition (swallowing), require the rapid, vigorous contraction, characteristic of the voluntary muscular tissue--FLINT.] (See p. 276.) The cells are filled with a fluid or semifluid mass of living (protoplasmic) matter. FIG. 15. [Illustration: _Microscopic view of a Muscle, showing, at one end, the fibrillæ; and, at the other, the disks, or cells, of the fiber._] The binding of so many threads into one bundle [Footnote: We shall learn hereafter how these fibers are firmly tied together by a mesh of fine connective tissue which dissolves in boiling, as just described] confers great strength, according to a mechanical principle that we see exemplified in suspension bridges, where the weight is sustained, not by bars of iron, but by small wires twisted into massive ropes. FIG. 16. [Illustration: _Tendons of the Hand._] THE TENDONS.--The ends of the muscles are generally attached to the bone by strong, flexible, but inelastic tendons. [Footnote: The tendons may be easily seen in the leg of a turkey as it comes on our table; so we may study Physiology while we pick the bones.] The muscular fibers spring from the sides of the tendon, so that more of them can act upon the bone than if they went directly to it. Besides, the small, insensible tendon can better bear the exposure of passing over a joint, and be more easily lodged in some protecting groove, than the broad, sensitive muscle. This mode of attachment gives to the limbs strength, and elegance of form. Thus, for example, if the large muscles of the arm extended to the hand, they would make it bulky and clumsy. The tendons, however, reach only to the wrist, whence fine cords pass to the fingers (Fig. 16). Here we notice two other admirable arrangements. 1. If the long tendons at the wrist on contracting should rise, projections would be made and thus the beauty of the slender joint be marred. To prevent this, a stout band or bracelet of ligament holds them down to their place. 2. In order to allow the tendon which moves the last joint of the finger to pass through, the tendon which moves the second joint divides at its attachment to the bone (Fig. 16). This is the most economical mode of packing the muscles, as any other practicable arrangement would increase the bulk of the slender finger. FIG. 17. [Illustration: _Muscles of the Right Eye:_ A, _superior straight,_ B, _superior oblique passing through a pulley,_ D; G, _inferior oblique,_ H, _external straight, and, back of it, the internal straight muscle._] Since the tendon can not always pull in the direction of the desired motion, some contrivance is necessary to meet the want. The tendon (B) belonging to one of the muscles of the eye, for example, passes through a ring of cartilage, and thus a rotary motion is secured. FIG. 18. [Illustration: _The three classes of Levers, and also the foot as a Lever._] THE LEVERS OF THE BODY. [Footnote: A _lever_ is a stiff bar resting on a point of support, called the _fulcrum_ (_F_), and having connected with it a _weight_ (_W_) to be lifted, and a _power_ (_P_) to move it. There are three classes of levers according to the arrangement of the power, weight, and fulcrum. In the first class, the _F_ is between the _P_ and _W_; in the second, the _W_ is between the _P_ and _F_; and in the third, the _P_ is between the _W_ and _F_ (Fig. 18). A pump handle is an example of the first; a lemon squeezer, of the second; and a pair of fire tongs, of the third. See "Popular Physics," pp. 81-83, for a full description of this subject, and for many illustrations.]--In producing the motions of the body, the muscles use the bones as levers. We see an illustration of the _first class_ of levers in the movements of the head. The back or front of the head is the weight to be lifted, the backbone is the fulcrum on which the lever turns, and the muscles at the back or front of the neck exert the power by which we toss or bow the head. FIG. 19. [Illustration: _The hand as a Lever of the third class._] When we raise the body on tiptoe, we have an instance of the _second class_. Here, our toes resting on the ground form the fulcrum the muscles of the calf (gas-troc-ne'-mi-us, _j_ and so-le'-us, Fig. 14), acting through the tendon of the heel, [Footnote: This is called the Tendon of Achilles (_k_, Fig. 14) and is so named because, as the fable runs, when Achilles was an infant his mother held him by the heel while she dipped him in the River Styx, whose water had the power of rendering one invulnerable to any weapon. His heel, not being wet, was his weak point, to which Paris directed the fatal arrow--"This tendon," says Mapother, "will bear one thousand pounds weight before it will break." The horse is said to be "hamstrung," and is rendered useless, when the Tendon of Achilles is cut. (see p. 284.)] are the power and the weight is borne by the ankle joint. An illustration of the _third class_ is found in lifting the hand from the elbow. The hand is the weight, the elbow the fulcrum, and the power is applied by the biceps muscle at its attachment to the radius (A, Fig. 19.) In this form of the lever there is great loss of force, because it is applied at such a distance from the weight, but there is a gain of velocity, since the hand moves so far by such a slight contraction of the muscle. The hand is required to perform quick motions, and therefore this mode of attachment is desirable. The nearer the power is applied to the resistance, the more easily the work is done. In the lower jaw, for example, the jaw is the weight, the fulcrum is the hinge joint at the back, and the muscles (temporal, _d_, and the mas'-se'ter, _e_, Fig. 14) on each side are the power. [Footnote: We may feel the contraction of the masseter by placing our hand on the face when we work the jaw, while the temporal can be readily detected by putting the fingers on the temple while we are chewing. The tendon of the muscle (digastric)--one of those which open the jaw--passes through a pulley (_c_, Fig. 14) somewhat like the one in the eye.] They act much closer to the resistance than those in the hand, since here we desire force, and there, speed. FIG. 20. [Illustration: _The Kneejoint;_ k, _the patella;_ f, _the tendon._] THE ENLARGEMENT OF THE BONES AT THE JOINTS not only affords greater surface for the attachment of the muscles, as we have seen, but also enables them to work to better advantage. Thus, in Fig. 20 it is evident that a muscle acting in the line _f b_ would not bend the lower limb so easily as if it were acting in the line _f k_, since in the former case its force would be about all spent in drawing the bones more closely together, while in the latter it would pull more nearly at a right angle. Thus the tendon _f_, by passing over the patella, which is itself pushed out by the protuberance _b_ of the thigh bone, pulls at a larger angle, [Footnote: The chief use of the processes of the spine (Fig. 6) and other bones is, in the same way, to throw out the point on which the power acts as far from the fulcrum as possible. The projections of the ulna ("funny bone") behind the elbow, and that of the heel bone to which the Tendon of Achilles is attached, are excellent illustrations (Fig. 1).] and so the leg is thrown forward with ease in walking and with great force in kicking. HOW WE STAND ERECT.--The joints play so easily, and the center of gravity in the body is so far above the foot, that the skeleton can not of itself hold our bodies upright. Thus it requires the action of many muscles to maintain this position. The head so rests upon the spine as to tend to fall in front, but the muscles of the neck steady it in its place. [Footnote: In animals the jaws are so heavy, and the place where the head and spine join is so far back, that there can be no balance as there is in man. There are therefore large muscles in their necks. We readily find that we have none if we get on "all fours" and try to hold up the head. On the other hand, gorillas and apes can not stand erect like man, for the reason that their head, trunk, legs, etc., are not balanced by muscles, so as to be in line with one another.] The hips incline forward, but are held erect by the strong muscles of the back. The trunk is nicely balanced on the head of the thigh bones. The great muscles of the thigh acting over the kneepan tend to bend the body forward, but the muscles of the calf neutralize this action. The ankle, the knee, and the hip lie in nearly the same line, and thus the weight of the body rests directly on the keystone of the arch of the foot. So perfectly do these muscles act that we never think of them until science calls our attention to the subject, and yet to acquire the necessary skill to use them in our infancy needed patient lessons, much time, and many hard knocks. FIG. 21. [Illustration: _Action of the Muscles which keep the body erect._] HOW WE WALK.--Walking is as complex an act as standing. It is really a perilous performance, which has become safe only because of constant practice. We see how violent it is when we run against a post in the dark, and find with what headlong force we were hurling ourselves forward. Holmes has well defined walking as a perpetual falling with a constant self-recovery. Standing on one foot, we let the body fall forward, while we swing the other leg ahead like a pendulum. Planting that foot on the ground, to save the body from falling farther, we then swing the first foot forward again to repeat the same operation. [Footnote: It is a curious fact that one side of the body tends to outwalk the other; and so, when a man is lost in the woods, he often goes in a circle, and at last comes round to the spot whence he started.] The shorter the pendulum, the more rapidly it vibrates; and so short- legged people take quicker and shorter steps than long-legged ones. [Footnote: In this respect, Tom Thumb was to Magrath, whose skeleton, eight and one half feet high, is now in the Dublin Museum, what a little fast-ticking, French mantel clock is to a big, old-fashioned, upright, corner timepiece.] We are shorter when walking than when standing still, because of this falling forward to take a step in advance. [Footnote: Women find that a gown that will swing clear of the ground when they are standing still, will drag the street when they are walking. The length of the step may be increased by muscular effort, as when a line of soldiers keep step in spite of their having legs of different lengths. Such a mode of walking is necessarily fatiguing. (See p. 280.)] In running, we incline the body more, and so, as it were, fall faster. When we walk, one foot is on the ground all the time, and there is an instant when both feet are planted upon it; but in running there is an interval of time in each step when both feet are off the ground, and the body is wholly unsupported. As we step alternately with the feet, we are inclined to turn the body first to one side and then to the other. This movement is sometimes counterbalanced by swinging the hand on the opposite side. [Footnote: In ordinary walking the speed is nearly four miles an hour, and can be kept up for a long period. But exercise and a special aptitude for it enable some men to walk great distances in a relatively short space of time. Trained walkers have gone seventy-five miles in twenty hours, and walked the distance of thirty-seven miles at the rate of five miles an hour. The mountaineers of the Alps are generally good walkers, and some of them are not less remarkable for endurance than for speed. Jacques Balmat, who was the first to reach the summit of Mont Blanc, at sixteen years of age could walk from the hamlet of the Pélerins to the mountain of La Côte in two hours,--a distance which the best- trained travelers required from five to six hours to get over. At the time of his last attempt to reach the top of Mont Blanc, this same guide, then twenty years old, passed six days and four nights without sleeping or reposing a single moment. One of his sons, Édouard Balmat, left Paris to join his regiment at Genoa; he reached Chamouni the fifth day at evening, having walked three hundred and forty miles. After resting two days, he set off again for Genoa, where he arrived in two days. Several years afterward, this same man left the baths at Louèche at two o'clock in the morning, and reached Chamouni at nine in the evening, having walked a distance equal to about seventy-five miles in nineteen hours. In 1844, an old guide of De Saussure, eighty years old, left the hamlet of Prats, in the valley of Chamouni, in the afternoon, and reached the Grand-Mulets at ten in the evening; then, after resting some hours, he climbed the glacier to the vicinity of the Grand Plateau, which has an altitude of about thirteen thousand feet, and then returned to his village without stopping.--_Wonders of the Body_.] THE MUSCULAR SENSE.--When we lift an object, we feel a sensation of weight, which we can compare with that experienced in lifting another body. [Footnote: If a small ivory ball be allowed to roll down the cheek toward the lips, it will appear to increase in weight. In general, the more sensitive parts of the body recognize smaller differences in weight, and the right hand is more accurate than the left. We are very apt, however, to judge of the weight of a body from previous conceptions. Thus, shortly after Sir Humphrey Davy discovered the metal potassium, he placed a piece of it in the hand of Dr. Pierson, who exclaimed: "Bless me! How heavy it is!" Really, however, potassium is so light that it will float on water like cork.] By balancing it in the hand. The muscular sense is useful to us in many ways. It guides us in standing or moving. We gratify it when we walk erect and with an elastic step, and by dancing, jumping, skating, and gymnastic exercises. NECESSITY OF EXERCISE.--The effect of exercise upon a muscle is very marked. [Footnote: The greater size of the breast (pectoral muscle) of a pigeon, as compared with that of a duck, shows how muscle increases with use. The breast of a chicken is white because it is not used for flight, and therefore gets little blood.] By use it grows larger, and becomes hard, compact, and darker-colored; by disuse it decreases in size, and becomes soft, flabby, and pale. Violent exercise, however, is injurious, since we then tear down faster than nature can build up. Feats of strength are not only hurtful, but dangerous. Often the muscles are strained or ruptured, and blood vessels burst in the effort to outdo one's companions. [Footnote: Instances have been known of children falling dead from having carried to excess so pleasant and healthful an amusement as jumping the rope, and of persons rupturing the Tendon of Achilles in dancing. The competitive lifting of heavy weights is unwise, sometimes fatal.] (See p. 278.) Two thousand years ago, Isocrates, the Greek rhetorician, said: "Exercise for health, not for strength." The cultivation of muscle for its own sake is a return to barbarism, while it enfeebles the mind, and ultimately the body. The ancient gymnasts are said to have become prematurely old, and the trained performers of our own day soon suffer from the strain they put upon their muscular system. Few men have sufficient vigor to become both athletes and scholars. Exercise should, therefore, merely supplement the deficiency of our usual employment. _A sedentary life needs daily, moderate exercise, which always stops short of fatigue_. This is a law of health. (See p. 280.) No education is complete which fails to provide for the development of the muscles. Recesses should be as strictly devoted to play as study hours are to work. Were gymnastics or calisthenics as regular an exercise as grammar or arithmetic, fewer pupils would be compelled to leave school on account of ill health; while spinal curvatures, weak backs, and ungraceful gaits would no longer characterize so many of our best institutions. TIME FOR EXERCISE.--We should not exercise after long abstinence from food, nor immediately after a meal, unless the meal or the exercise be very light. There is an old-fashioned prejudice in favor of exercise before breakfast--an hour suited to the strong and healthy, but entirely unfitted to the weak and delicate. On first rising in the morning, the pulse is low, the skin relaxed, and the system susceptible to cold. Feeble persons, therefore, need to be braced with food before they brave the outdoor air. WHAT KIND OF EXCERCISE TO TAKE.--For children, games are unequaled. Walking, the universal exercise, [Footnote: The custom of walking, so prevalent in England, has doubtless much to do with the superior physique of its people. It is considered nothing for a woman to take a walk of eight or ten miles, and long pedestrian excursions are made to all parts of the country. The benefits which accrue from such an open-air life are sadly needed by the women of our own land. A walk of half a dozen miles should be a pleasant recreation for any healthy person.] is beneficial, as it takes one into the open air and sunlight. Running is better, since it employs more muscles, but it must not be pushed to excess, as it taxes the heart, and may lead to disease of that organ. Rowing is more effectual in its general development of the system. Swimming employs the muscles of the whole body, and is a valuable acquirement, as it may be the means of saving life. Horseback riding is a fine accomplishment, and refreshes both mind and body. Gymnastic or calisthenic exercises bring into play all the muscles of the body, and when carefully selected, and not immoderately employed, are preferable to any other mode of indoor exercise. [Footnote: The employment of the muscles in exercise not only benefits their especial structure, but it acts on the whole system. When the muscles are put in action, the capillary blood vessels with which they are supplied become more rapidly charged with blood, and active changes take place, not only in the muscles, but in all the surrounding tissues. The heart is required to supply more blood, and accordingly beats more rapidly in order to meet the demand. A larger quantity of blood is sent through the lungs, and larger supplies of oxygen are taken in and carried to the various tissues. The oxygen, by combining with the carbon of the blood and the tissues, engenders a larger quantity of heat, which produces an action on the skin, in order that the superfluous warmth may be disposed of. The skin is thus exercised, as it were, and the sudoriparous and sebaceous glands are set at work. The lungs and skin are brought into operation, and the lungs throw off large quantities of carbonic acid, and the skin large quantities of water, containing in solution matters which, if retained, would produce disease in the body. Wherever the blood is sent, changes of a healthful character occur. The brain and the rest of the nervous system are invigorated, the stomach has its powers of digestion improved, and the liver, pancreas, and other organs perform their functions with more vigor. By want of exercise, the constituents of the food which pass into the blood are not oxidized, and products which produce disease are engendered. The introduction of fresh supplies of oxygen induced by exercise oxidizes these products, and renders them harmless. As a rule, those who exercise most in the open air will live the longest.--LANKESTER.] (See p. 280.) THE WONDERS OF THE MUSCLES.--The grace, ease, and rapidity with which the muscles contract are astonishing. By practice, they acquire a facility which we call mechanical. The voice may utter one thousand five hundred letters in a minute, yet each requires a distinct position of the vocal organs. We train the muscles of the fingers till they glide over the keys of the piano, executing the most exquisite and difficult harmony. In writing, each letter is formed by its peculiar motions, yet we make them so unconsciously that a skillful penman will describe beautiful curves while thinking only of the idea that the sentence is to express. The mind of the violinist is upon the music which his right hand is executing, while his left determines the length of the string and the character of each note so carefully that not a false sound is heard, although the variation of a hair's breadth would cause a discord. In the arm of a blacksmith, the biceps muscle may grow into the solidity almost of a club; the hand of a prize fighter will strike a blow like a sledge hammer; while the engraver traces lines invisible to the naked eye, and the fingers of the blind acquire a delicacy that almost supplies the place of the missing sense. DISEASES, ETC.--l. _St. Vitus's Dance_ is a disease of the voluntary muscles, whereby they are in frequent, irregular, and spasmodic motion beyond the control of the will. All causes of excitement, and especially of fear, should be avoided, and the general health of the patient invigorated, as this disease is closely connected with a derangement of the nervous system. 2. _Convulsions_ are an involuntary contraction of the muscles. Consciousness is wanting, while the limbs may be stiff or in spasmodic action. (See p. 261.) 3. _Locked-jaw_ is a disease in which there are spasms and a contraction of the muscles, usually beginning in the lower jaw. It is serious, often fatal, yet it sometimes follows as trivial an injury as the stroke of a whip lash, the lodgment of a bone in the throat, a fishhook in the finger, or a tack in the sole of the foot. 4. _Gout_ is characterized by an acute pain located chiefly in the small joints of the foot, especially those of the great toe, which become swollen and extremely sensitive. It is generally accompanied by an excess of uric acid in the blood, and a deposit of urate of soda about the affected joint. Gout is often the result of high living, and of too much animal food. It is frequently inherited. 5. _Rheumatism_ affects mainly the connective, white, fibrous tissue of the larger joints. While gout is the punishment of the rich who live luxuriously, rheumatism afflicts alike the poor and the rich. There are two common forms of rheumatism--the inflammatory or acute, and the chronic. The latter is of long continuance; the former terminates more speedily. The acute form is probably a disease of the blood, which carries with it some poisonous matter that is deposited where the fibrous tissue is most abundant. The disease flies capriciously from one joint to another, and the pain caused by even the slightest motion deprives the sufferer of the use of the disabled part and its muscles. Its chief danger lies in the possibility of its affecting the vital organs. Chronic rheumatism--the result of repeated attacks of the acute--leads to great suffering, and oftentimes to disorganization of the joints and an interference with the movements of the heart. 6. _Lumbago_ is an inflammation of the lumbar muscles and fascia. [Footnote: Lumbago is really a form of myalgia, a disease which, has its seat in the muscles, and may thus affect any part of the body. Doubtless much of what is commonly called "liver" or "kidney complaint" is only, in one case, myalgia of the chest or abdominal walls near the liver, or, in the other, of the back and loins near the kidneys. Chronic liver disease is comparatively rare in the Northern States, and pain in the side is not a prominent symptom; while certain diseases of the kidneys, which are as surely fatal as pulmonary consumption, are not attended by pain in the back opposite these organs.--WEY.] It may be so moderate as to produce only a "lame back," or so severe as to disable, as in the case of what is popularly termed a "crick in the back." Strong swimmers who sometimes drown without apparent cause are supposed to be seized in this way. 7. _A Ganglion_, or what is vulgarly called a "weak" or "weeping" sinew, is the swelling of a bursa. [Footnote: A bursa is a small sack containing a lubricating fluid to prevent friction where tendons play over hard surfaces. There is one shaped like an hourglass on the wrist, just at the edge of the palm. By pressing back the liquid it contains, this bursa may be clearly seen.] It sometimes becomes so distended by fluid as to be mistaken for bone. If on binding something hard upon it for a few days it does not disappear, a physician will remove the liquid by means of a hypodermic syringe, or perhaps cause it to be absorbed by an external application of iodine. PRACTICAL QUESTIONS. 1. What class of lever is the foot when we lift a weight on the toes? 2. Explain the movement of the body backward and forward, when resting upon the thigh bone as a fulcrum. 3. What class of lever do we use when we lift the foot while sitting down? 4. Explain the swing of the arm from the shoulder. 5. What class of lever is used in bending our fingers? 6. What class of lever is our foot when we tap the ground with our toes? 7. What class of lever do we use when we raise ourselves from a stooping position? 8. What class of lever is the foot when we walk? 9. Why can we raise a heavier weight with our hand when lifting from the elbow than from the shoulder? 10. What class of lever do we employ when we are hopping, the thigh bone being bent up toward the body and not used? 11. Describe the motions of the bones when we are using a gimlet. 12. Why do we tire when we stand erect? 13. Why does it rest us to change our work? 14. Why and when is dancing a beneficial exercise? 15. Why can we exert greater force with the back teeth than with the front ones? 16. Why do we lean forward when we wish to rise from a chair? 17. Why does the projection of the heel bone make walking easier? 18. Does a horse travel with less fatigue over a flat than a hilly country? 19. Can you move your upper jaw? 20. Are people naturally right or left-handed? 21. Why can so few persons move their ears by the muscles? 22. Is the blacksmith's right arm healthier than the left? 23. Boys often, though foolishly, thrust a pin into the flesh just above the knee. Why is it not painful? 24. Will ten minutes' practice in a gymnasium answer for a day's exercise? 25. Why would an elastic tendon be unfitted to transmit the motion of a muscle? 26. When one is struck violently on the head, why does he instantly fall? 27. What is the cause of the difference between light and dark meat in a fowl? III. THE SKIN. A protection from the outer world, it is our only means of communicating with it. Insensible itself, it is the organ of touch. It feels the pressure of a hair, yet bears the weight of the body. It yields to every motion of that which it wraps and holds in place. It hides from view the delicate organs within, yet the faintest tint of a thought shines through, while the soul paints upon it, as on a canvas, the richest and rarest of colors. ANALYSIS OF THE SKIN. _ _ | 1. The Cutis; its Composition and Character. | 1. THE STRUCTURE | 2. The Cuticle; its Composition and Character. | OF THE SKIN. | 3. The Value of the Cuticle. | |_4. The Complexion. | _ | | a. _Description._ | _ | b. _Method of Growth._ | | 1. The Hair.....| c. _As an Instrument of | | | Feeling._ | 2. THE HAIR AND | | d. _Indestructibility of | THE NAILS. | |_ the Hair._ | | _ | |_2. The Nails....| a. _Uses._ | |_b. _Method of Growth._ | _ | 3. THE MUCOUS | 1. The Structure. | MEMBRANE | 2. Connective Tissue. | |_3. Fat. | _ | | 1. Number and Kinds of Teeth. | | _ | | 1. The Two Sets.| 1. _The Milk Teeth._ | | |_2. _The Permanent Teeth._ | | | 4. THE TEETH. | 2. Structure of the Teeth. | | 3. The Setting of the Tooth in the Jaw. | | 4. The Decay of the Teeth. | |_5. The Preservation of the Teeth. | _ _ | | 1. The Two Kinds.| 1. _Oil Glands._ | | |_2. _Perpiratory Glands._ | | | 5. THE GLANDS | 2. The Perspiration. | | 3. The Absorbing Power of the Skin. (See | |_ Lymphatics.) | _ | | 1. About Washing and Bathing. | | 2. The Reaction. | | 3. Sea Bathing. _ | 6. HYGIENE | | a. _General Principles._ | | | b. _Linen._ | | | c. _Cotton._ | |_4. Clothing.......| d. _Woolen._ | | e. _Flannel._ | | f. _Color of Clothing._ | | g. _Structure of | | Clothing._ | | h. _Insufficient | _ |_ Clothing._ | | 1. Erysipelas. | | 2. Salt Rheum. |_7. DISEASES. | 3. Corns. | 4. Ingrowing Nails. | 5. Warts. |_6. Chilblains. THE SKIN. THE SKIN is a tough, thin, close-fitting garment for the protection of the tender flesh. Its perfect elasticity beautifully adapts it to every motion of the body. We shall learn hereafter that it is more than a mere covering, being an active organ, which does its part in the work of keeping in order the house in which we live. It oils itself to preserve its smoothness and delicacy, replaces itself as fast as it wears out, and is at once the perfection of use and beauty. 1. STRUCTURE OF THE SKIN. CUTIS AND CUTICLE.--What we commonly call the skin--viz., the part raised by a blister--is only the cuticle [Footnote: _Cuticula_, little skin. It is often styled the scarfskin, and also the epidermis (_epi_, upon; and _derma_, skin).] or covering of the cutis or true skin. The latter is full of nerves and blood vessels, while the former neither bleeds [Footnote: We notice this in shaving; for if a razor goes below the cuticle, it is followed by pain and blood. So insensible is this outer layer that we can run a pin through the thick mass at the roots of the nails without discomfort.] nor gives rise to pain, neither suffers from heat nor feels the cold. The cuticle is composed of small, flat cells or scales. These are constantly shed from the surface in the form of scurf, dandruff, etc., but are as constantly renewed from the cutis [Footnote: We see how rapidly this change goes on by noticing how soon a stain of any kind disappears from the skin. A snake throws off its cuticle entire, and at regular intervals.] below. Under the microscope, we can see the round cells of the cuticle, and how they are flattened and hardened as they are forced to the surface. The immense number of these cells surpasses comprehension. In one square inch of the cuticle, counting only those in a single layer, there are over a billion horny scales, each complete in itself.--HARTING. FIG. 22. [Illustration: A _represents a vertical section of the Cuticle._ B, _lateral view of the cells._ C, _flat side of scales like_ d, _magnified 250 diameters, showing the nucleated cells transformed into broad scales._] VALUE OF THE CUTICLE.--In the palm of the hand, the sole of the foot, and other parts especially liable to injury, the cuticle is very thick. This is a most admirable provision for their protection. [Footnote: We can hold the hand in strong brine with impunity, but the smart will quickly tell us when there is even a scratch in the skin. Vaccine matter must be inserted beneath the cuticle to take effect. This membrane doubtless prevents many poisonous substances from entering the system.] By use, it becomes callous and horny. The boy who goes out barefoot for the first time, "treading as if on eggs," can soon run where he pleases among thistles and over stones. The blacksmith handles hot iron without pain, while the mason lays stones and works in lime, without scratching or corroding his flesh. THE COMPLEXION.--In the freshly made cells on the lower side of the cuticle, is a pigment composed of tiny grains. [Footnote: These grains are about 1/2000 of an inch in diameter, and, curiously enough, do not appear opaque, but transparent and nearly colorless.--MARSHALL.] In the varying tint of this coloring matter, lies the difference of hue between the blonde and the brunette, the European and the African. In the purest complexion, there is some of this pigment, which, however, disappears as the fresh, round, soft cells next the cutis change into the old, flat, horny scales at the surface. Scars are white, because this part of the cuticle is not restored. The sun has a powerful effect upon the coloring matter, and so we readily "tan" on exposure to its rays. If the color gathers in spots, it forms freckles. [Footnote: This action of the sun on the pigment of the skin is very marked. Even among the Africans, the skin is observed to lose its intense black color in those who live for many months in the shades of the forest. It is said that Asiatic and African women confined within the walls of the harem, and thus secluded from the sun, are as fair as Europeans. Among the Jews who have settled in Northern Europe, are many of light complexion, while those who live in India are as dark as the Hindoos. Intense heat also increases this coloring matter, and thus a furnace-man's skin, even where protected by clothing, becomes completely bronzed. The black pigment has been known to disappear during severe illness, and a lighter color to be developed in its place. Among the negroes, are sometimes found people who have no complexion, _i. e._, there is no coloring matter in their skin, hair, or the iris of their eyes. These persons are called Albinos.] II. HAIR AND NAILS. The Hair and the Nails are modified forms of the cuticle. FIG. 23. [Illustration: A _Hair, magnified 600 diameters._ S, _the sac (follicle);_ P, _the papilla, showing the cells and the blood vessels:_ V.] THE HAIR is a protection from heat and cold, and shields the head from blows. It is found on nearly all parts of the body, except the palms of the hands and the soles of the feet. The outside of a hair is hard and compact, and consists of a layer of colorless scales, which overlie one another like the shingles of a house; the interior is porous, [Footnote: In order to examine a hair, it should be put on the slide of the microscope, and covered with a thin glass, while a few drops of alcohol are allowed to flow between the cover and the slide. This causes the air, which fills the hair and prevents our seeing its structure, to escape.] and probably conveys the liquids by which it is nourished. Each hair grows from a tiny bulb (papilla), which is an elevation of the cutis at the bottom of a little hollow in the skin. From the surface of this bulb, the hair is produced, like the cuticle, by the constant formation of new cells at the bottom. When the hair is pulled out, this bulb, if uninjured, will produce a new one; but, when once destroyed, it will never grow again. [Footnote: Hair grows at the rate of about five to seven inches in a year. It is said to grow after death. This appearance is due to the fact that by the shrinking of the skin the part below the surface is caused to project, which is especially noticeable in the beard.] The hair has been known to whiten in a single night by fear, fright, or nervous excitement. When the color has once changed, it can not be restored. [Footnote: Hair dyes, or so-called "hair restorers," are almost invariably deleterious substances, depending for their coloring properties upon the action of lead or lunar caustic. Frequent instances of hair poisoning have occurred, owing to the common use of such dangerous articles. If the growth of the hair be impaired, the general constitution or the skin needs treatment. This is the work of a skillful physician, and not of a patent remedy. Dame Fashion has her repentant freaks as well as her ruinous follies, and it is a healthful sign that the era of universal hair dyeing has been blotted out from her present calendar, and the gray hairs of age are now honored with the highest place in "style" as well as in good sense and cleanliness.] (See p. 285.) Wherever hair exists, tiny muscles are found, interlaced among the fibers of the skin. These, when contracting under the influence of cold or electricity, pucker up the skin, and cause the hair to stand on end. [Footnote: In horses and other animals which are able to shake the whole skin, this muscular tissue is much more fully developed than in man.] The hairs themselves are destitute of feeling. Nerves, however, are found in the hollows in which the hair is rooted, and so one feels pain when it is pulled. [Footnote: These nerves are especially abundant in the whiskers of the cat, which are used as feelers.] Thus the insensible hairs become wonderfully delicate instruments to convey an impression of even the slightest touch. FIG. 24. [Illustration: A, _a perspiratory tube with its gland;_ B, _a hair with a muscle and two oil glands;_ C, _cuticle;_ D, _the papillæ;_ and E, _fat cells._] Next to the teeth and bones, the hair is the least destructible part of the body, and its color is often preserved for many years after the other portions have gone to decay. [Footnote: Fine downy hairs, such as are general upon the body, have been detected in the little fragments of skin found beneath the heads of the nails by which, centuries ago, certain robbers were fastened to the church doors, as a punishment for their sacrilege.] THE NAILS protect the ends of the tender finger, and toe, and give us power more firmly to grasp and easily to pick up any object we may desire. They enable us to perform a hundred little, mechanical acts which else were impossible. At the same time, their delicate color and beautiful outline give a finish of ornament to that exquisite instrument, the hand. The nail is firmly set in a groove (matrix) in the cuticle, from which it grows at the root in length [Footnote: By making a little mark on the nail near the root we can see, week by week, how rapidly this process goes on, and so form some idea of what a multitude of cells must be transformed into the horny matter of the nail.] and from beneath in thickness. So long as the matrix at the root is uninjured, the nail will be replaced after any accident. (See p. 288.) III. THE MUCOUS MEMBRANE. STRUCTURE.--At the edges of the openings into the body, the skin seems to stop and give place to a tissue which is redder, more sensitive, more liable to bleed, and is moistened by a fluid, or mucus, as it is called. Really, however, the skin does not cease, but passes into a more delicate covering of the same general structure, viz., an outer, hard, bloodless, insensible layer, and an inner, soft, sanguine, nervous one. [Footnote: With a dull knife, we can scrape from the mucous membrane which lines the mouth some of the cuticle for examination under the microscope. In a similar way, we can obtain cuticle from the surface of the body for study and comparison.] Thus every part of the body is wrapped in a kind of double bag, made of tough skin on the outside, and tender mucous membrane on the inside. CONNECTIVE TISSUE.--The cutis and the corresponding layer of the mucous membrane consist chiefly of a fibrous substance interlaced, like felt. It is called connective tissue, because it connects all the different parts of the body. It spreads from the cutis, invests muscles, bones, and cartilages, and thence passes into the mucous membrane. So thoroughly does it permeate the body, that, if the other tissues were destroyed, it would give a perfect model of every organ. [Footnote: It is curious to notice how our body is wrapped in membrane. On the outside, is the skin protecting from exterior injury, and, on the inside, is the mucous membrane reaching from the lips to the innermost air cell of the lungs. Every organ is enveloped in its membrane. Every bone has its sheath. Every socket is lined. Even the separate fibers of muscles have their covering tissue. The brain and the spinal cord are triply wrapped, while the eye is only a membranous globe filled with fluid. These membranes protect and support the organs they enfold, but, with that wise economy so characteristic of nature everywhere, they have also an important function to perform. They are the _filters_ of the body. Through their pores pass alike the elements of growth, and the returning products of waste. On one side, bathed by the blood, they choose from it suitable food for the organ they envelop, and many of them in their tiny cells, by some mysterious process, form new products,--put the finishing touches, as it were, upon the material ere it is deposited in the body.] It can be seen in a piece of meat as a delicate substance lying between the layers of muscle, where it serves to bind together the numerous fibers of which they are composed. Connective tissue yields gelatine on boiling, and is the part which tans when hides are manufactured into leather. It is very elastic, so that when you remove your finger after pressing upon the skin, no indentation is left. [Footnote: In dropsy, this elasticity is lost by distension, and there is a kind of "pitting," as it is called, produced by pressure.] It varies greatly in character,--from the mucous membrane, where it is soft and tender, to the ligaments and tendons which it largely composes, where it is strong and dense. [Footnote: The leather made from this tissue varies as greatly, from the tough, thick oxhide, to the soft, pliable kid and chamois skin.] FAT is deposited as an oil in the cells [Footnote: So tiny are these cells, that there are over sixty-five million in a cubic inch of fat. As they are kept moist, the liquid does not ooze out, but, on drying, it comes to the surface, and thus a piece of fat feels oily when exposed to the air. The quantity of fat varies with the state of nutrition. In corpulent persons, the masses of fat beneath the skin, in the mesentery, on the surface of the heart and great vessels, between the muscles, and in the neighborhood of the nerves, are considerably increased. Conversely, in the emaciated we sometimes find beneath the skin nucleated cells, which contain only one oil drop. Many masses of fat which have an important relation to muscular actions--such as the fat of the orbit or the cheek-- do not disappear in the most emaciated object. Even in starvation, the fatty substances of the brain and spinal cord are retained.--VALENTIN.] of this tissue, just beneath the skin (Fig. 24), giving roundness and plumpness to the body, and acting as an excellent nonconductor for the retention of heat. It collects as pads in the hollows of the bones, around the joints, and between the muscles, causing them to glide more easily upon each other. As marrow, it nourishes the skeleton, and also distributes the shock of any jar the limb may sustain. It is noticeable, however, that fat does not gather within the cranium, the lungs, or the eyelids, where its accumulation would clog the organs. IV. THE TEETH. THE TEETH [Footnote: Although the teeth are always found in connection with the skeleton, and are, therefore, figured as a part of it (Fig. 1), yet they do not properly belong to the bones of the body, and are merely set in the solid jaw to insure solidity. They are hard, and resemble bony matter, yet they are neither true bone nor are they formed in the same manner. "They are properly appendages of the mucous membrane, and are developed from it."--LEIDY. "They belong to the Tegumentary System, which, speaking generally of animals, includes teeth, nails, horns, scales, and hairs."--MARSHALL. They are therefore classed with the mucous membrane, as are the nails and hair with the skin.] are thirty-two in all,--there being eight in each half jaw, similarly shaped and arranged. In each set of eight, the two nearest the middle of the jaw have wide, sharp, chisel-like edges, fit for cutting, and hence are called _incisors_. The next one corresponds to the great tearing or holding tooth of the dog, and is styled the _canine_, or eye-tooth. The next two have broader crowns, with two points, or cusps, and are hence termed the _bicuspids_. The remaining three are much broader, and, as they are used to crush the food, are called the _grinders_, or _molars_. The incisors and eyeteeth have one fang, or root; the others have two or three fangs. THE MILK TEETH.--We are provided with two sets of teeth. The first, or milk teeth, are small and only twenty in number. In each half jaw there are two incisors, one canine, and two molars. The middle incisors are usually cut about the age of seven months, the others at nine months, the first molars at twelve months, the canines at eighteen months, and the remaining molars at two or three years of age. The lower teeth precede the corresponding upper ones. The time often varies, but the order seldom. THE PERMANENT TEETH.--At six years, when the first set is usually still perfect, the jaws contain the crowns of all the second, except the wisdom teeth. About this age, to meet the wants of the growing body, the crowns of the permanent set begin to press against the roots of the milk teeth, which, becoming absorbed, leave the loosened teeth to drop out, while the new ones rise and occupy their places. [Footnote: If the milk teeth, do not promptly loosen on the appearance of the second set, the former should be at once removed to permit the permanent teeth to assume their natural places. If any fail to come in regularly, or if they crowd the others, a competent dentist should be consulted.] FIG. 25. [Illustration: _The teeth at the age of six and one half years._ I, _the incisors;_ O, _the canine;_ M, _the molars; the last molar is the first of the permanent teeth;_ F, _sacs of the permanent incisors;_ C, _of the canine;_ B, _of the bicuspids;_ N, _of the second molar; the sac of the third molar is empty._-- MARSHALL.] The central incisors appear at about seven years of age; the others at eight; the first bicuspids at nine, the second at ten; the canines at eleven or twelve; the second [Footnote: The first molar appears much earlier. (See Fig. 25.)] molars at twelve or thirteen, and the last, or wisdom teeth, are sometimes delayed until the twenty-second year, or even later. STRUCTURE OF THE TEETH.--The interior of the tooth consists principally of _dentine_, a dense substance resembling bone. [Footnote: In the tusk of the elephant this is known as ivory.] The crown of the tooth, which is exposed to wear, is protected by a sheath of _enamel_. This is a hard, glistening, white substance, containing only two and a half per cent of animal matter. The fang is covered by a thin layer of true bone (cement). FIG. 26. [Illustration: _Vertical section of a Molar Tooth, moderately magnified._ a, _enamel of the crown, the lines of which indicate the arrangement of its columns;_ b, _dentine;_ c, _cement;_ d, _pulp cavity._] At the center of the tooth is a cavity filled with a soft, reddish-white, pulpy substance full of blood vessels and nerves. This pulp is very sensitive, and toothache is caused by its irritation. THE FITTING OF THE TOOTH INTO THE JAW is a most admirable contrivance. It is not set like a nail in wood, having the fang in contact with the bone; but the socket is lined with a membrane which forms a soft cushion. While this is in a healthy state, it deadens the force of any shock, but, when inflamed, it becomes the seat of excruciating pain. THE DECAY OF THE TEETH [Footnote: Unlike the other portions of the body, there is no provision made for any change in the permanent teeth. That part, however, which is thus during life most liable to change, after death resists it the longest. In deep-sea dredgings teeth are found when all traces of the frame to which they belonged have disappeared. Yet hard and incorruptible as they seem, their permanence is only relative. Exposed to injury and disease, they break or decay. Even if they escape accident, they yet wear at the crown, are absorbed at the fang, and, in time, drop out, thus affording another of the many signs of the limitations Providence has fixed to the endurance of our bodies and the length of our lives.] is commonly caused (1) by portions of the food which become entangled between them, and, on account of the heat and moisture, quickly decompose; and (2) by the saliva, as it evaporates, leaving on the teeth a sediment, which we call tartar. This collects organic matter that rapidly changes, and also affords a soil in which a sort of fungus speedily springs up. From both these causes, the breath becomes offensive, and the teeth are injured. PRESERVATION OF THE TEETH.--Children should early be taught to brush their teeth at least every morning with tepid water, and twice a week with white castile soap and powdered orris root, or with some dentifrice recommended by a responsible dentist. They should also be instructed to remove the particles of food from between the teeth, after each meal, by means of a quill or wooden toothpick. The enamel once injured is never restored, and the whole interior of the tooth is exposed to decay. We should not, therefore, crack hard nuts, bite thread, or use metal toothpicks, gritty tooth powders, or any acid which "sets the teeth on edge," _i. e._. that acts upon the enamel. It is well also to have the teeth examined yearly by a dentist, that any small orifice may be filled, and further decay prevented. V. THE GLANDS OF THE SKIN. 1. THE OIL GLANDS are clusters of tiny sacs which secrete an oil that flows along the duct to the root of the hair, and thence oozes out on the cuticle (Fig. 24). [Footnote: This secretion is said to vary in different persons, and on that account the dog is enabled to trace his master by the scent.] This is nature's efficient hair-dressing, and also keeps the skin soft and flexible. These glands are not usually found where there is no hair, as on the palm of the hand, and hence at those points only can water readily soak through the skin into the body. They are of considerable size on the face, especially about the nose. When obstructed, their contents become hard and dark-colored, and are vulgarly called "worms." [Footnote: Though they are not alive, yet, under the microscope, they are sometimes found to contain a curious parasite, called the pimple mite, which is supposed to consume the superabundant secretion.] II. THE PERSPIRATORY GLANDS are fine tubes about 1/300 of an inch in diameter, and a quarter of an inch in length, which run through the cutis, and then coil up in little balls (Fig. 24). They are found in all parts of the body, and in almost incredible numbers. In the palm of the hand, there are about two thousand eight hundred in a single square inch. On the back of the neck and trunk, where they are fewest, there are yet four hundred to the square inch. The total number on the body of an adult is estimated at about two and a half million. If they were laid end to end, they would extend nearly ten miles. [Footnote: The current statement, that they would extend twenty-eight miles, is undoubtedly an exaggeration. Krause estimates the total number at 2,381,248, and the length of each coil, when unraveled, at 1/10 of an inch, which would make the total length much less than even the statement in the text. Seguin states that the proportion of impurities thrown off by the skin and the lungs, is eleven to seven.] The mouths of these glands--"pores," as we commonly call them--may be seen with a pocket lens along the fine ridges which cover the palm of the hand. THE PERSPIRATION.--From these openings, there constantly passes a vapor, forming what we call the insensible perspiration. Exercise or heat causes it to flow more freely, when it condenses on the surface in drops. The perspiration consists of about ninety-nine parts water, and one part solid matter. The amount varies greatly, but on the average is, for an adult, not far from two pounds per day. Any suppression of this constant drainage will lead to disagreeable and even dangerous results. If it be entirely and permanently checked, death will inevitably ensue. [Footnote: Once, on an occasion of great solemnity at Rome, a child was, it is said, completely covered with gold leaf, closely applied to the skin, so as to represent, according to the idea of that age, the golden glory of an angel or seraph. In a few hours, after contributing to this pageant, the child died; the cause being suffocation, from stopping the exhalation of the skin; although, in the ignorance of the common people of those days, the death was attributed to the anger of the Deity, and looked upon as a circumstance of evil omen.] THE ABSORBING POWER OF THE SKIN.--We have already described two uses of the skin: (1) Its _protective_, (2) its _exhaling_, and now we come to (3) its _absorbing_ power. This is not so noticeable as the others, and yet it can be illustrated. Persons frequently poison their hands with the common wood ivy. Contagious diseases are taken by touching a patient, or even his clothing, especially if there be a crack in the cuticle. [Footnote: If one is called upon to handle a dead body, it is well, especially if the person has died of a contagious disease, to rub the hand with lard or olive oil. Poisonous matter has been fatally absorbed through the breaking of the cuticle by a hangnail, or a simple scratch. There is a story that Bonaparte, when a lieutenant of artillery, in the heat of battle, seized the rammer and worked the gun of an artilleryman who had fallen. From the wood which the soldier had used, Bonaparte absorbed a poison that gave him a skin disease, by which he was annoyed the remainder of his life.] Painters absorb so much lead through the pores of their hands that they are attacked with colic. [Footnote: Cosmetics, hair dyes, etc., are exceedingly injurious, not only because they tend to fill the pores of the skin, but because they often contain poisonous matters that may be absorbed into the system, especially if they are in a solution.] Snuff and lard are frequently rubbed on the chest of a child suffering with the croup, to produce vomiting. It is said that seamen in want of water drench their clothing in salt spray, when the skin will absorb enough moisture to quench thirst (see Lymphatic System). By carefully conducted experiments, it has been found that the skin acts in the same way as the lungs (see Respiration) in absorbing oxygen from the air, and giving off carbonic acid to a small but appreciable amount. Indeed, the skin has not inaptly been styled the third lung. Hence, the importance of absolute cleanliness and a frequent ablution of the entire body. VI. HYGIENE. HINTS ABOUT WASHING AND BATHING.--The moment of rising from bed is the proper time for the full wash or bath with which one should commence the day. The body is then warm, and can endure moderately cold water better than at any other time; it is relaxed, and needs bracing; and the nerves, deadened by the night's repose, require a gentle stimulus. If the system be strong enough to resist the shock, cold water is the most invigorating; if not, a tepid bath will answer. [Footnote: Many persons have not the conveniences for a bath. To them, the following plan, which the author has daily employed for years, is commended. The necessities are: a basin full of soft water, a mild soap, a large sponge or a piece of flannel, and two towels--one soft, the other rough. The temperature of the water should vary with the season of the year--cold in summer and tepid in winter. Rub quickly the entire body with the wet sponge or flannel. (If more agreeable, wash and wipe only a part at a time, protecting the rest in cold weather with portions of clothing.) Dry the skin gently with a soft towel, and when quite dry, with the rough towel or flesh brush rub the body briskly four or five minutes till the skin is all aglow. The chest and abdomen need the principal rubbing. The roughness of the towel should be accommodated to the condition of the skin. Enough friction, however, must be given to produce at least a gentle warmth, indicative of the reaction necessary to prevent subsequent chill or languor. An invalid will find it exceedingly beneficial if a stout, vigorous person produce the reaction by rubbing with the hands.] Before dressing, the whole body should be thoroughly rubbed with a coarse towel or flesh brush. At first, the friction may be unpleasant, but this sensitiveness will soon be overcome, and the keenest pleasure be felt in the lively glow which follows. A bath should not be taken just before nor immediately after a meal, as it will interfere with the digestion of the food. Soap should be employed occasionally, but its frequent use tends to make the skin dry and hard. REACTION.--After taking a cold bath, there should be a prompt reaction. When the surface is chilled by cold water, the blood sets to the heart and other vital organs, exciting them to more vigorous action, and then, being thrown back to the surface, it reddens, warms, and stimulates the skin to an unwonted degree. This is called the reaction, and in it lies the invigorating influence of the cold bath. When, on the contrary, the skin is heated by a hot bath, the blood is drawn to the surface, less blood goes to the heart, the circulation decreases, and languor ensues. A dash of cold water is both necessary and refreshing at the close of a hot bath. [Footnote: The Russians are very fond of vapor baths, taken in the following manner. A large room is heated by stoves. Red-hot stones being brought in, water is thrown upon them, filling the room with steam. The bathers sit on benches until they perspire profusely, when they are rubbed with soapsuds and dashed with cold water. Sometimes, while in this state of excessive perspiration, they run out of doors and leap into snow banks.] If, after a cold bath, there be felt no glow of warmth, but only a chilliness and depression, we are thereby warned that either proper means were not taken to bring on this reaction, or that the circulation is not vigorous enough to make such a bath beneficial. The general effect of a cool bath is exhilarating, and that of a warm one depressing. [Footnote: The sudden plunge into a cold bath is good for the strong and healthy, but too severe for the delicate. One should always wet first the face, neck, and chest. It is extremely injurious to stand in a bath with only the feet and the lower limbs covered by the water, for the blood is thus sent from the extremities to the heart and internal organs, and they become so burdened that reaction may be out of their power. A brisk walk, or a thorough rubbing of the skin, before a cold bath or swim, adds greatly to its value and pleasure.] Hence the latter should not ordinarily be taken oftener than once a week, while the former may be enjoyed daily. (See p. 289.) SEA BATHING is exceedingly stimulating, on account of the action of the salt and the exciting surroundings. Twenty minutes is the utmost limit for bathing or swimming in salt or fresh water. A chilly sensation should be the signal for instant removal. It is better to leave while the glow and buoyancy which follow the first plunge are still felt. Gentle exercise after a bath is beneficial. CLOTHING in winter, to keep us warm, should repel the external cold and retain the heat of the body. In summer, to keep us cool, it should not absorb the rays of the sun, and should permit the passage of the heat of the body. At all seasons, it should be porous, to give ready escape to the perspiration, and a free admission of air to the skin. We can readily apply these essential conditions to the different kinds of clothing. _Linen_ is soft to the touch, and is a good conductor of heat. Hence it is pleasant for summer wear, but, being apt to chill the surface too rapidly, it should not be worn next the skin. _Cotton_ is a poorer conductor of heat and absorber of moisture, and is therefore warmer than linen. It is sufficiently cool for summer wear, and affords better protection against sudden changes. _Woolen_ absorbs moisture slowly, and contains much air in its pores. It is therefore a poor conductor of heat, and guards the wearer against the vicissitudes of our climate. The outer clothing may be adapted largely to ornament, and may be varied to suit our fancy and the requirements of society. The underclothing should always be sufficient to keep us warm. Woolen should be worn next the skin at all times; light gossamer garments in the heat of summer, and warm, porous flannels in midwinter. Light-colored clothing is not only cooler in summer, but warmer in winter. As the warmth of clothing depends greatly on the amount of air contained in its fibers, fine, loose, porous cloth with a plenty of nap is best for winter wear. Firm and heavy goods are not necessarily the warmest. Furs are the perfection of winter clothing, since they combine warmth with lightness. Two light woolen garments are warmer than one heavy one, as there is between them a layer of nonconducting air. All the body except the head should be equally protected by clothing. Whatever fashion may dictate, no part covered to-day can be uncovered tonight or to-morrow, except at the peril of health. It is a most barbarous and cruel custom to leave the limbs of little children unprotected, when adults would shiver at the very thought of exposure. Equally so is it for children to be thinly clad for the purpose of hardening them. To go shivering with cold is not the way to increase one's power of endurance. The system is made more vigorous by exercise and food; not by exposure. In winter, we should wear warm shoes with thick soles, and rubbers when it is damp. At night, and after exercise, we require extra clothing. (See p. 295.) DISEASES, ETC.--l. _Erysipelas_ is an inflammation (see Inflammation) of the skin, and often begins in a spot not larger than a pin head, which spreads with great rapidity. It is very commonly checked by the application of a solution of iodine. The burning and contracting sensation may be relieved by cloths wrung out of hot water. 2. _Eczema_ (Salt Rheum, etc.) is of constitutional origin. It is characterized by an itching, burning, reddened eruption, in which a serous discharge exudes and dries into crusts or scales. The skin thickens in patches, and painful fissures are formed, which are irritated by exposure to air or water. Eczema denotes debility. It occurs in various forms, and, like erysipelas, should be treated by a physician. 3. _Corns_ are thickened cuticle, caused by pressure or friction. They most frequently occur on the feet; but are produced on the shoemaker's knee by constant hammering, and on the soldier's shoulder by the rubbing of his musket. This hard portion irritates the sensitive cutis beneath, and so causes pain. A corn will soften in hot water, when it may be pared with a sharp knife. If the cause be removed, the corn will not return. 4. _Ingrowing Nails_ are caused by pressure, which forces the edge of the toe nail into the flesh. They may be cured by carefully cutting away the part which has mal-grown, and then scraping the back of the nail till it is thin, making a small incision in the center, at the top. The two portions, uniting, will draw away the nail from the flesh at the edge. Ingrowing nails may be prevented by wearing broad-toed shoes. 5. _Warts_ are overgrown papillæ (Fig. 24). They may generally be removed by the application of glacial acetic acid, or a drop of nitric acid, repeated until the entire structure is softened. Care must be taken to keep the acid from touching the neighboring skin. The capricious character of warts has given rise to the popular delusion concerning the influence of charms upon them. 6. _Chilblain_ is a local inflammation affecting generally the feet, the hands, or the lobes of the ear. Liability to it usually passes away with manhood. It is not caused by "freezing the feet," as many suppose, though attacks are brought on, or aggravated, by exposure to cold, followed by sudden warming. Chilblain is subject to daily congestion (see Congestion), manifested by itching, soreness, etc., commonly occurring at night. The best preventive is a uniform temperature, and careful protection against the cold by warm clothing, especially for the feet. PRACTICAL QUESTIONS. 1. If a hair be plucked out, will another grow in its place? 2. What causes the hair to "stand on end" when we are frightened? 3. Why is the skin roughened by riding in the cold? 4. Why is the back of a washerwoman's hand less water-soaked than the palm? 5. What would be the length of the perspiratory tubes in a single square inch of the palm, if placed end to end? 6. What colored clothing is best adapted to all seasons? 7. What is the effect of paint and powder on the skin? 8. Is waterproof clothing healthful for constant wear? 9. Why are rubbers cold to the feet? 10. Why does the heat seem oppressive when the air is moist? 11. Why is friction of the skin invigorating after a cold bath? 12. Why does the hair of domestic animals become roughened in winter? 13. Why do fowls spread their feathers before they perch for the night? 14. How can an extensive burn produce congestion of the lungs? 15. Why do we perspire so profusely after drinking cold water? 16. How can we best prevent skin diseases, colds, and rheumatism? 17. What causes the difference between the hard hand of a blacksmith and the soft hand of a woman? 18. Why should a painter avoid getting paint on the palm of his hand? 19. Why should we not use the soap or the soiled towel at a hotel? 20. Which teeth cut like a pair of scissors? 21. Which teeth cut like a chisel? 22. Which should be clothed the warmer, a merchant or a farmer? 23. Why should we not crack nuts with our teeth? 24. Do the edges of the upper and the lower teeth meet? 25. When fatigued, would you take a cold bath? 26. Why is the outer surface of a kid glove finer than the inner? 27. Why will a brunette endure the sun's rays better than a blonde? 28. Does patent leather form a healthful covering for the feet? 29. Why are men more frequently bald than women? 30. On what part of the head does baldness commonly occur? Why? 31. What does the combination in our teeth of canines and grinders suggest as to the character of our food? 32. Is a staid, formal promenade suitable exercise? 33. Is there any danger in changing the warm clothing of our daily wear for the thin one of a party? 34. Should we retain our overcoat, shawl, or furs when we come into a warm room? 35. Which should bathe the oftener, students or outdoor laborers? 36. Is abundant perspiration injurious? 37. How often should the ablution of the entire body be performed? 38. Why is cold water better than warm, for our daily ablution? 39. Why should our clothing always fit loosely? 40. Why should we take special pains to avoid clothing that is colored by poisonous dyestuffs? (See p. 296.) 41. What general principles should guide us as to the length and frequency of baths In salt or fresh water? 42. What is the beneficial effect of exercise upon the functions of the skin? 43. How can we best show our admiration and respect for the human body? 44. Why is the scar of a severe wound upon a negro sometimes white? IV. RESPIRATION AND THE VOICE. "The smooth soft air with pulse-like waves Flows murmuring through its hidden caves, Whose streams of brightening purple rush, Fired with a new and livelier blush; While all their burden of decay The ebbing current steals away." ANALYSIS OF RESPIRATION AND THE VOICE. _ | 1. The Larnyx. _ | 2. The Vocal Cords. | 1. ORGANS OF VOICE.....| 3. Different Tones of Voice. | | 4. Speech. | |_5. Formation of Vocal Sounds. | _ | | 1. The Trachea. | | 2. The Bronchial Tubes. | 2. ORGANS OF RESPIRA- | 3. The Cells. | TION.........| 4. The Lung Wrapping. | |_5. The Cilia. | _ | | 1. Inspiration. | 3. HOW WE BREATHE......|_2. Expiration. | _ | | 1. Sighing. | | 2. Coughing. | | 3. Sneezing. | 4. MODIFICATIONS OF | 4. Snoring. | THE BREATH.......| 5. Laughing, and Crying. | | 6. Hiccough. | |_7. Yawning. | | 5. CAPACITY OF THE LUNGS. | _ | | 1. The Need of Air. | | 2. Action of Air in the Lungs. | | 3. Tests of the Breath. | | 4. Analysis of Expired Air. | | 5. Effect of Rebreathed Air. | | _ | 6. HYGIENE.............| | a. _The Sources of | | | Impurity._ | | | b. _The Sick Room._ | | 6. Concerning | c. _The Sitting Room._ | | the Need of | d. _The Bedroom._ | |_ Ventilation.| e. _The Church._ | | f. _The Schoolroom._ | | g. _How we should | |_ Ventilate._ | | 7. THE WONDERS OF RESPIRATION. | _ | | 1. Constriction of the Lungs. | | 2. Bronchitis. | | 3. Pleurisy. | | 4. Pneumonia. |_8. DISEASES............| 5. Consumption | 6. Asphyxia. | 7. Diptheria. | 8. Croup. |_9. Stammering. RESPIRATION AND THE VOICE. The Organs of Respiration and the Voice are the _larynx_, the _trachea_, and the _lungs_. DESCRIPTION OF THE ORGANS OF THE VOICE.--l. _The Larynx_.--In the neck, is a prominence sometimes called Adam's apple. It is the front of the _larynx_. This is a small triangular, cartilaginous box, placed just below the root of the tongue, and at the top of the windpipe. The opening into it from the throat is called the _glottis_; and the cover, the _epiglottis_ (_epi_, upon; _glotta_, the tongue). The latter is a spoon-shaped lid, which opens when we breathe, but, by a nice arrangement, shuts when we try to swallow, and so lets our food slip over it into the _œsophagus_ (e-sof'-a-gus), the tube leading from the pharynx to the stomach (Fig. 27). If we laugh or talk when we swallow, our food is apt to "go the wrong way," _i. e._, little particles pass into the larynx, and the tickling sensation which they produce forces us to cough in order to expel the intruders. 2. _The Vocal Cords_.--On each side of the _glottis_ are the so- called _vocal cords_. They are not really cords, but merely elastic membranes projecting from the sides of the box across the opening. [Footnote: The cartilages and vocal cords may be readily seen in the larynx of an ox or sheep. If the flesh be cut off, the cartilages will dry, and will keep for years.] When not in use, they spread apart and leave a V-shaped orifice (Fig. 28), through which the air passes to and from the lungs. If the cords are tightened, the edges approach sometimes within 1/100 of an inch of each other, and, being thrown into vibration, cause corresponding vibrations in the current of air. Thus sound is produced in the same manner as by the vibrations of the tongues of an accordion, or the strings of a violin, only in this case the strings are scarcely an inch long. FIG. 27. [Illustration: _Passage to the Œsophagus and Windpipe._ c, _the tongue;_ d, _the soft palate, ending in_ g, _the uvula;_ h, _the epiglottis;_ i, _the glottis;_ I, _the œsophagus;_ f, _the pharynx._] DIFFERENT TONES OF THE VOICE.--The higher tones of the voice are produced when the cords are short, tight, and closely in contact; the lower, by the opposite conditions. Loudness is regulated by the quantity of air and force of expulsion. A falsetto voice is thought to be the result of a peculiarity in the pharynx (Fig. 27) at the back part of the nose; it is more probably produced by some muscular maneuver not yet fully understood. When boys are about fourteen years of age, the larynx enlarges, and the cords grow proportionately longer and coarser; hence, the voice becomes deeper, or, as we say, "changes." The peculiar harshness of the voice at this time seems to be due to a congestion of the mucous membrane of the cords. The change may occur very suddenly, the voice breaking in a single night. FIG. 28. [Illustration: e, e, _the vocal cords;_ d, _the epiglottis._] Speech is voice modulated by the lips, tongue, [Footnote: The tongue is styled the "unruly member," and held responsible for all the tattling of the world; but when the tongue is removed, the adjacent organs in some way largely supply the deficiency, so that speech is still possible. Huxley describes the conversation of a man who had two and one half inches of his tongue preserved in spirits, and yet could converse intelligibly. Only the two letters _t_ and _d_ were beyond his power; the articulation of these involves the employment of the tip of the tongue; hence, "tin" he converted into "fin," and "dog" into "thog."] palate, and teeth. [Footnote: An artificial larynx may be made by using elastic bands to represent the vocal cords, and by placing above them chambers which by their resonance will produce the same effect as the cavities lying above the larynx. An artificial speaking machine was constructed by Kempelen, which could pronounce such sentences as, "I love you with all my heart," in different languages, by simply touching the proper keys.] Speech and voice are commonly associated, but speech may exist without the voice, for when we whisper we articulate the words, although there is no vocalization, _i. e._, no action of the larynx. [Footnote: We can observe this by placing the hand on the throat, and noticing the absence of vibrations when we whisper, and their presence when we talk. The difference between vocalization and non-vocalization is seen in a sigh and a groan, the latter being the former vocalized. Whistling is a pure mouth sound, and does not depend on the voice. Laughter is vocal, being the aspirated vowels, a, e, or o, convulsively repeated.] (See p. 297.) FIG. 29. [Illustration: _The Lungs, showing the Larynx._ A, _the windpipe;_ B, _the bronchial tubes._] FORMATION OF VOCAL SOUNDS.--The method of modulating voice into speech may be seen by producing the pure vowel sounds _a, e_, etc., from one expiration, the mouth being kept open while the form of the aperture is changed for each vowel by the tongue and the lips. _H_ is only an explosion, or forcible throwing of a vowel sound from the mouth. [Footnote: When, in sounding a vowel, the sound coincides with a sudden change in the position of the vocal cords from one of divergence to one of approximation, the vowel is pronounced with the _spiritus asper_. When the vocal cords are brought together before the blast of air begins, the vowel is pronounced with the _spiritus lenis._--FOSTER.] The consonants, or short sounds, may also be made without interrupting the current of air, by various modifications of the vocal organs. In sounding singly any one of the letters, we can detect its peculiar requirements. Thus _m_ and _n_ can be made only by blocking the air in the mouth and sending it through the nose; _l_ lets the air escape at the sides of the tongue; _r_ needs a vibratory movement of the tongue; _b_ and _p_ stop the breath at the lips; _k_ and _g_ (hard), at the back of the palate. Consonants like _b_ and _d_ are abrupt, or, like _l_ and _s_, continuous. Those made by the lips are termed _labials_; those by pressing the tongue against the teeth, _dentals_; those by the tongue, _linguals_. The child gains speech slowly, first learning to pronounce the vowel _a_, the consonants _b, m_, and _p_, and then their unions --_ba, ma, pa_. DESCRIPTION OF THE ORGANS OF RESPIRATION.--Beneath the larynx is the windpipe, or _trachea_ (see Fig. 29), so called because of its roughness. It is strengthened by C-shaped cartilages with the openings behind, where they are attached to the œsophagus. At the lower end, the trachea divides into two branches, called the right and left _bronchi_. These subdivide in the small bronchial tubes, which ramify through the lungs like the branches of a tree, the tiny twigs of which at last end in clusters of cells so small that there are six hundred million in all. This cellular structure renders the lungs exceedingly soft, elastic, and sponge-like. [Footnote: The lungs of slaughtered animals are vulgarly called "lights," probably on account of their lightness. They are similar in structure to those of man. They will float on water, and if a small piece be forcibly squeezed between the fingers (notice the creaking sound it gives), it will retain sufficient air to make it buoyant.] FIG. 30. [Illustration: _Bronchial Tubes, with clusters of cells._] The stiff, cartilaginous rings, so noticeable in the rough surface of the trachea and the bronchi, disappear as we reach the smaller bronchial tubes, so that while the former are kept constantly open for the free admission of air, the latter are provided with elastic fibers by which they may be almost closed. WRAPPING OF THE LUNGS.--The lungs are invested with a double covering--the _pleura_--one layer being attached to the lungs and the other to the walls of the chest. It secretes a fluid which lubricates it, so that the layers glide upon each other with perfect ease. [Footnote: These pleural sacs are distinct and closed; hence, when the ribs are raised, a partial vacuum being formed in the sacs, air rushes in, and distends the pulmonary lobules.] The lungs are lined with mucous membrane, exceedingly delicate and sensitive to the presence of anything except pure air. We have all noticed this when we have breathed any thing offensive. FIG. 31. [Illustration: A, _the heart;_ B, _the lungs drawn aside to show the internal organs;_ C, _the diaphragm;_ D, _the liver;_ E, _the gall cyst;_ F, _the stomach;_ G,_ the small intestines;_ H, _the transverse colon._] THE CILIA.--Along the air passages are minute filaments (_cilia_, Fig. 32), which are in constant motion, like a field of grain stirred by a gentle breeze. They serve to fan the air in the lungs, and produce an outward current, which is useful in catching dust and fine particles swept inward with the breath. HOW WE BREATHE.--Respiration consists of two acts--taking in the air, or _inspiration_, and expelling the air, or _expiration_. FIG. 32. [Illustration: B, _a section of the mucous membrane, showing the cilia rising from the peculiar epithelial cells on the outside of the mucous membrane lining the tubes;_ A, _a single cell more highly magnified._] 1. _Inspiration_.--When we draw in a full breath, we straighten the spine and throw the head and shoulders back, so as to give the greatest advantage to the muscles. [Footnote: If we examine the bony cage of the thorax or chest in Fig. 8, we shall see that the position of the ribs may alter its capacity in two ways. 1. As they run obliquely downward from the spine, if the sternum or breastbone be lifted in front, the diameter of the chest will be increased. 2. The ribs are fastened by elastic cartilages, which stretch as the muscles that lift the ribs contract, and so increase the breadth of the chest.] At the same time, the diaphragm [Footnote: The diaphragm is the muscular partition between the chest and the abdomen. It is always convex toward the former, and concave toward the latter (Fig. 31). Long muscular fibers extend from its center toward the ribs in front and the spine at the back. When these contract, they depress and flatten the diaphragm; when they relax, it becomes convex again. In the former case, the bowels are pressed downward and the abdomen pushed outward; in the latter, the bowels spring upward, and the abdomen is drawn inward.] descends and presses the walls of the abdomen outward. Both these processes increase the size of the chest. Thereupon, the elastic lungs expand to occupy the extra space, while the air, rushing in through the windpipe, pours along the bronchial tubes and crowds into every cell. [Footnote: It is said that in drawing a full breath, the muscles exert a force equal to raising a weight of seven hundred and fifty pounds. When we are about to make a great effort, as in striking a heavy blow, we naturally take a deep inspiration, and shut the glottis. The confined air makes the chest tense and firm, and enables us to exert a greater force. As we let slip the blow, the glottis opens and the air escapes, often with a curious aspirated sound as is noticeable in workmen. To make a good shot with a rifle, we should take aim with a full chest and tight breath, since then the arms will have a steadier support.] 2. _Expiration_.--When we forcibly expel the air from our lungs, the operation is reversed. We bend forward, draw in the walls of the abdomen, and press the diaphragm upward, while the ribs are pulled downward,--all together diminishing the size of the chest, and forcing the air outward. Ordinary, quiet breathing is performed mainly by the diaphragm,--one breath to every four beats of the heart, or eighteen per minute. (See p. 299.) MODIFICATIONS OF THE BREATH.--_Sighing_ is merely a prolonged inspiration followed by an audible expiration. _Coughing_ is a violent expiration in which the air is driven through the mouth. _Sneezing_ differs from coughing, the air being forced through the nose. _Snoring_ is produced by the passage of the breath through the pharynx when the tongue and soft palate are in certain positions. [Footnote: The soft palate must have fallen back in such a manner as nearly or quite to close the entrance to the nasal cavity from the throat, and the tongue must also be thrown back so far as to leave only a narrow opening between it and the soft palate. The noise is produced by the air being forced either inward or outward through this opening. A snore results also when, with a closed mouth, the air is forced between the soft palate and the back wall of the pharynx into the nasal cavity. With deep breathing, perhaps accompanied by a variation in the position of the soft palate, a rattling noise may be heard in addition to the snoring, which is due to a vibration of the soft palate.--F. A. FERNALD, in "How we Sneeze, Laugh, Stammer, and Sigh."--_Popular Science Monthly_, Feb., 1884.] _Laughing_ and _crying_ are very much alike. The expression of the face is necessary to distinguish between them. The sounds are produced by short, rapid contractions of the diaphragm. _Hiccough_ is confined to inspiration. It is caused by a contraction of the diaphragm and a constriction of the glottis; the current of air just entering, as it strikes the closed glottis, gives rise to the well-known sound. _Yawning_, or _gaping_, is like sighing. [Footnote: The usefulness of a yawn lies in bringing up the arrears, as it were, of respiration, when it has fallen behindhand, either through fatigue or close attention to other occupation. The stretching of the jaws and limbs may also serve to equalize the nervous influence, certain muscles having become uneasy on account of being stretched or contracted for a long time.] It is distinguished by a wide opening of the mouth and a deep, profound inspiration. Both processes furnish additional air, and therefore probably meet a demand of the system for more oxygen. Frequently, however, they are like laughing, sobbing, etc., merely a sort of contagion, which runs through an audience, and seems almost irresistible. THE CAPACITY OF THE LUNGS.--If we take a deep inspiration, and then forcibly exhale all the air we can expel from the lungs, this amount, which is termed the _breathing capacity_, will bear a very close correspondence to our stature. For a man of medium height (five feet eight inches) it will be about two hundred and thirty cubic inches, [Footnote: Of this amount, one hundred cubic inches can be forced in only by an extra effort, and is available for emergencies, or for purposes of training, as in singing, climbing, etc. It is of great importance, since, if the capacity of the lungs only equaled our daily wants, the least obstruction would prove fatal.] or a gallon, and for each inch of height between five and six feet there will be an increase of eight cubic inches. In addition, it is found that the lungs contain about one hundred cubic inches which can not be expelled, thus making their entire contents about three hundred and thirty cubic inches, or eleven pints. The extra amount always on hand in the lungs is of great value, since thereby the action of the air goes on continuously, even during a violent expiration. In ordinary breathing, only about twenty or thirty cubic inches (less than a pint) of air pass in and out. THE NEED OF AIR.--The body needs food, clothing, sunshine, bathing, and. drink; but none of these wants is so pressing as that for air. The other demands may be met by occasional supplies, but air must be furnished every moment or we die. Now the vital element of the atmosphere is oxygen gas. [Footnote: See "Steele's Popular Chemistry," p. 30. The atmosphere consists of one fifth oxygen and four fifths nitrogen. The former is the active element; and the latter, the passive. Oxygen alone would be too stimulating, and must be restrained by the neutral nitrogen. Separately, either element of the air would kill us.] This is a stimulating, life- giving principle. No tonic will so invigorate as a few full, deep breaths of cold, pure air. Every organ will glow with the energy of the fiery oxygen. ACTION OF THE AIR IN THE LUNGS.--In the delicate cells of the lungs, the air gives up its oxygen to the blood, and receives in turn carbonic-acid [Footnote: More properly _Carbon dioxide_.] gas and water, foul with waste matter which the blood has picked up in its circulation through the body. The blood, thus purified and laden with the inspiring oxygen, goes bounding through the system, while the air we exhale carries off the impurities. In this process, the blood changes from purple to red. If we examine our breath, we can readily see what it has removed from the blood. TESTS OF THE BREATH.--1. Breathe into a jar, and on lowering into it a lighted candle, the flame will be instantly extinguished; thus indicating the presence of carbonic-acid gas. 2. Breathe upon a mirror, and a film of moisture will show the vapor. [Footnote: There is a close relation between the functions of the skin, the lungs, and the kidneys--the scavengers of the body. They all carry off water from the blood, and when the function of one of the three is, in this respect, interfered with, the others are called upon to perform its functions. When the function of perspiration is deranged, the lungs and kidneys are required to perform heavier duty, and this may lead to disease (see p. 62).] 3. If breath be confined in a bottle, the animal matter will decompose and give off an offensive odor. ANALYSIS OF THE EXPIRED AIR shows that it has lost about twenty-five per cent of its oxygen, and gained an equal amount of carbonic-acid gas, besides moisture, and organic impurities. Our breath, then, is air robbed of its vitality, and containing in its place a gas as fatal to life [Footnote: Carbonic-acid gas can not be breathed when undiluted, as the glottis closes and forbids its passage into the lungs. Air containing only three or four per cent acts as a narcotic poison (MILLER), and a much smaller proportion will have an injurious effect. The great danger, however, lies in the organic particles constantly exhaled from the lungs and the skin, which, it is believed, are often direct and active poisons.] as it is to a flame, and effete matter which is disagreeable to the smell, injurious to the health, and which may contain the germs of serious disease. THE EVIL EFFECT OF REBREATHING the air can not be overestimated. We take back into our bodies that which has just been rejected. The blood thereupon leaves the lungs, bearing, not the invigorating oxygen, but refuse matter to obstruct the whole system. We soon feel the effect. The muscles become inactive. The blood stagnates. The heart acts slowly. The food is undigested. The brain is clogged. The head aches. Instances of fatal results are only too frequent. [Footnote: During the English war in India, in the eighteenth century, one hundred and forty-six prisoners were shut up in a room scarcely large enough to hold them. The air could enter only by two narrow windows. At the end of eight hours, but twenty-three persons remained alive, and these were in a most deplorable condition. This prison is well called "The Black Hole of Calcutta."--Percy relates that after the battle of Austerlitz, three hundred Russian prisoners were confined in a cavern, where two hundred and sixty of them perished in a few hours.--The stupid captain of the ship _Londonderry_, during a storm at sea, shut the hatches. There were only seven cubic feet of space left for each person, and in six hours ninety of the passengers were dead.] The constant breathing of even the slightly impure air of our houses can not but tend to undermine the health. The blood is not purified, and is thus in a condition to receive the seeds of disease at any time. The system uninspired by the energizing oxygen is sensitive to cold. The pale cheek, the lusterless eye, the languid step, speak but too plainly of oxygen starvation. In such a soil, catarrh, scrofula, and kindred diseases run riot. [Footnote: One not very strong, or unable powerfully to resist conditions unfavorable to health, and with a predisposition to lung disease, will be sure, sooner or later, by partial lung starvation and blood poisoning, to develop pulmonary consumption. _The lack of what is so abundant and so cheap--good, pure air--is unquestionably the one great cause of this terrible disease_.--BLACK'S _Ten Laws of Health_.] CONCERNING THE NEED FOR VENTILATION.--The foul air which passes off from the lungs and through the pores of the skin does not fall to the floor, but diffuses itself through the surrounding atmosphere. A single breath will to a trifling but certain extent taint the air of a whole room. [Footnote: This grows out of a well-known philosophical principle called the Diffusion of Gases, whereby two gases tend to mix in exact proportions, no matter what may be the quantity of each.--STEELE'S _Popular Chemistry,_ p. 86, and _Popular Physics,_ p. 52.] A light will vitiate as much air as a dozen persons. Many breaths and lights therefore rapidly unfit the air for our use. The perfection of ventilation is reached when the air of a room is as pure as that out of doors. To accomplish this result, it is necessary to allow for each person six hundred cubic feet of space, while ventilation is still going on in the best manner known. In spite of these well-known facts, scarcely any pains are taken to supply fresh air, while the doors and windows where the life-giving oxygen might creep in are hermetically stopped. How often is this true of the sick room. Yet here the danger of bad air is intensified. The expired breath of the patient is peculiarly threatening to himself as well as to others. Nature is seeking to throw off the poison of the disease. The scavengers of the body are all at work. The breath and the insensible perspiration are loaded with impurities. [Footnote: The floating dust in the air, revealed to us by the sunbeam shining through a crack in the blinds, shows the abundance of these impurities, and also the presence of germs which, lodging in the lungs, may implant disease, unless thrown off by a vigorous constitution. "On uncovering a scarlet fever patient, a cloud of fine dust is seen to rise from the body--contagious dust, that for days will retain its poisonous properties."--YOUMANS. (See p. 300.)] The odor is oftentimes exceedingly offensive. Sick and well alike need an abundance of fresh air. But, too often, it is the only want not supplied. Our sitting rooms, heated by furnaces or red-hot stoves, generally have no means of ventilation, or, if provided, they are seldom used. A window is occasionally dropped to give a little relief, as if pure air were a rarity, and must be doled out to the suffering lungs in morsels, instead of full and constant draughts. The inmates are starved by scanty lung food, and stupefied by foul air. The process goes on year by year. The weakened and poisoned body at last succumbs to disease, while we, in our blindness and ignorance, talk of the mysterious Providence which thus untimely cuts down the brightest intellects. The truth is, death is often simply the penalty for violating nature's laws. Bad air begets disease; disease begets death. In our churches, the foul air left by the congregation on Sunday is shut up during the week, and heated for the next Lord's day, when the people assemble to rebreathe the polluted atmosphere. They are thus forced, with every breath they take, to violate the physical laws of Him whom they meet to worship,--laws written not three thousand years ago upon Mount Sinai on tables of stone, but to-day engraved in the constitution of their own living, breathing bodies. On brains benumbed and starving for oxygen, the purest truth and the highest eloquence fall with little force. We sleep in a small bedroom from which every breath of fresh air is excluded, because we believe night air to be unhealthy, [Footnote: There is a singular prejudice against the night air. Yet, as Florence Nightingale aptly says, what other air can we breathe at night? We then have the choice between foul air within and pure air without. For, in large cities especially, the night air is far more wholesome than that of the daytime. To secure fresh air at night, we must open the windows of our bedroom.] and so we breathe its dozen hogsheads of air over and over again, and then wonder why we awaken in the morning so dull and unrefreshed! Return to our room after inhaling the fresh, morning air, and the fetid odor we meet on opening the door, is convincing proof how we have poisoned our lungs during the night. Each room should be supplied with two thousand feet of fresh air per hour for every person it contains. Our ingenuity ought to find some way of doing this advantageously and pleasantly. A moiety of the care we devote to delicate articles of food, drink, and dress would abundantly meet this prime necessity of our bodies. Open the windows a little at the top and the bottom. Put on plenty of clothing to keep warm by day and by night, and then let the inspiring oxygen come in as freely as God has given it. Pure air is the cheapest necessity and luxury of life. Let it not be the rarest! SCHOOLROOM VENTILATION.--Who, on going from the open air of a clear, bracing winter's day, into a crowded schoolroom, late in the session, has not noticed the disagreeable odor, and been for a moment nauseated and half stifled by the oppressive atmosphere! It is not strange. See how many causes here combine to pollute the air. If the room is heated by a stove, quantities of carbonic-oxide and carbonic-acid gases, as well as other products of combustion, driven by downward drafts in the flue, escape through seams and cracks and the occasionally opened door of the stove. In the case of a furnace, the same effect is too often experienced, and the odor of coal gas is a common one, especially when the fire is replenished. The insensible perspiration is more active in children than in adults; they, moreover, rush in with their clothing saturated with the perspiration induced by their sports; so that, on the average, each pupil, during school hours, loads the air with about half a pint of aqueous vapor. The children come, oftentimes, from homes that are close, ill- ventilated, and uncleanly; and frequently from sick rooms, bringing in their clothing the germs of disease. (See p. 304.) Some of the pupils may even bear traces of illness, or have unsound organs, and so their breath and exhalations be poisonous. In addition to all this, the air is filled with dust brought in and kept astir by many busy feet; with ashes floating from the stove or furnace; and especially with chalk dust. The modern method of teaching requires a large amount of blackboard work, and the air of the schoolroom is thus loaded with chalk particles. These collect in the nasal passages, and the upper part of the larynx, and irritate the membrane, perhaps laying the foundation of catarrh. The usual schoolroom atmosphere bears in the pupils the natural fruit of frequent headaches, inattention, weariness, and stupor; but in the teacher its frightful influence is most apparent. His labor is severe, his worry of mind is constant, and, when he finishes his day's work, he is generally too tired to take proper physical exercise. He consequently labors on with impaired health, or is forced to abandon his profession. Instead of six hundred feet of space being allowed for each pupil, as perfect ventilation demands--the lowest estimate being two hundred and fifty feet--often not over one hundred feet are afforded. Instead of two thousand cubic feet of fresh air being supplied every hour for each person, and as much foul air removed, which, all physiologists assert, is needed for perfect health, perhaps no means of ventilation at all are provided, and none is secured except what an occasionally opened door, or the benevolent cracks and chinks in the building furnish the suffering lungs. [Footnote: Imagine fifty pupils put into a class room thirty feet long, twenty-five feet wide, and ten feet high. This would generally be considered a very liberal provision. Such a room contains seven thousand five hundred cubic feet of air. But it furnishes only one hundred and fifty feet of space for each pupil. Allowing ten cubic feet of air per pupil each minute, in fifteen minutes after assembling, the entire atmosphere of the room is tainted, and unfit to be rebreathed. The demand of health is that at least one thousand five hundred cubic feet of pure air should be admitted into this room every minute, and as much be removed.] HOW SHALL WE VENTILATE?--The usual method of ventilation depends upon the fact that hot air is lighter than cold air, and so the cold air tends, by the force of gravity, to fall and compel the warm air to rise. Thus, if we open the door of a heated room, and hold a lighted candle first at the top, and then at the bottom, we can see, by the deflection of the flame, that there is a current of air setting outward at the top, and another setting inward at the bottom of the opening. A handkerchief held loosely, or the smoke of a smoldering match, in front of a fireplace will show a current of air passing up the chimney; this is caused by the difference of temperature between the air in the room and the outside atmosphere. _Upon this difference of temperature, all ordinary ventilation is based_. [Footnote: Public buildings are sometimes ventilated by mechanical means, _i. e._, immense fans which are turned by machinery, and thus set the air in motion. Such methods are, however, expensive, and rarely adopted, except where power is also used for other purposes.] A proper treatment of this subject and its practical applications, would require a book by itself. There is room here for only a few general statements and suggestions. 1. Two openings are always necessary to produce a thorough change of air. (See "Popular Chemistry," p. 70.) Put a lighted candle in a bottle. The flame will soon be extinguished. The oxygen of the little air in the bottle is burned out, and carbonic acid has taken its place. Now place over the mouth of the bottle a lamp chimney, and insert in the chimney a strip of cardboard, thus dividing the passage. On relighting the candle, it will burn freely. The smoke of a bit of smoldering paper will show that two opposite currents of air are established, one setting into the bottle, the other outward. 2. In the winter, when our schoolrooms, churches, public halls, etc., are heated artificially, ventilation is comparatively easy if properly arranged. [Footnote: For the escape of bad air, Dr. Bell suggests that an efficient foul-air shaft may be fitted to the commonest of stoves by simply inclosing the stovepipe in a jacket--that is, in a pipe two or three inches greater in diameter. This should be braced round the stovepipe and left open at the end next the stove. At its entrance into the chimney, a perforated collar should separate it from the stovepipe.] The required difference of temperature is kept up with little difficulty. The fresh air admitted to the room should then be heated [Footnote: Ventilation is change of air, and, unless scientifically arranged, and especially unless the incoming volume of air be warmed in cold weather, such change of atmosphere means cold currents, with their attendant train of catarrhs, bronchitis, neuralgia, rheumatism, and all the evils that spring from these diseases. The raw, damp, frosty air of our ever-changing winter temperature ought not to have uncontrolled and constant ingress to our dwellings. Air out of doors is suited to out of door habits. It is healthy and bracing when the body is coated and wrapped, and prepared to meet it, and when exercise can be taken to keep up the circulation; but to live under cover is to live artificially, and such essential conditions must be observed as suit an abnormal state. All the evils attaching to ventilation, as it is generally effected, spring from the neglect of this consistency.--_Westminster Review_.] either by a furnace, or by passing over a stove, or through a coil of steam pipes. This cold air should always be taken directly from out of doors, and not from a cellar, or from under a piazza, where contamination is possible. 3. In order to remove the impure air, there should be ventilators provided at or near the floor, opening into air shafts, or pipes leading upward through the roof, with proper orifices at the top. These ventilating pipes should be heated artificially so as to produce a draught. They may form one of the flues of a chimney in which there is a constant fire; or be carried upward in a large flue through the center of which runs the smoke pipe of the furnace or stove; [Footnote: This plan has been adopted in the newer school buildings of Elmira, N. Y. The older buildings were provided with ventilating pipes, not heated artificially, and hence of no service. These pipes are rendered effective, however, by conducting them into a small room in the garret, heated by a coal stove. From this room, a large exit pipe leads to the roof, where it terminates in an Emerson's ventilator. So strong a draught is thus established that throughout the building air is taken from the floors, and consequently the cooler portion of the rooms, at a velocity of three to five feet per second or one hundred and eighty to three hundred cubic feet per minute for each square foot of flue opening. In perpendicular flues, heated throughout with a smoke flue from the furnace, ten feet per second is attained.] or the ventilating pipe be itself conveyed through the center of the larger chimney flue. If the register for hot air be on the floor at one side of the room, two or more ventilators may be placed near the floor on the opposite side. The warm air will thus make the complete circuit of the room, and thoroughly warm it before passing out. If the ventilating shaft be not heated artificially; the ventilator must be placed at the top of the room in order that the hot air may escape through it, thus producing an upward draught. But the objection to this method is that it allows the warmer air to escape, while economy requires that the cooler air at the bottom of the room should be removed and the warm air be made to descend, thus securing uniformity of temperature. 4. In the summer, ventilation may be commonly provided for by opening windows _at the top and the bottom_, on the sheltered side of the building, so as to avoid draughts of air injurious to the occupants. On a dull, still, hot day, when there is little difference of temperature between the inner and the outer air, ventilation can be secured only by having a fire provided in the ventilating shaft; this, by exhausting the air from the room, will cause a fresh current to pour in through the open windows. At recess, all the children should, if the weather permit, be sent out of doors, to allow their clothing to be exposed to the purifying influence of the open air; meantime, the windows should be thrown wide open, that the room may be thoroughly ventilated during their absence. In bad weather, rapid marching or calisthenic exercises will furnish exercise, and also permit the airing of the room. 5. The school and the church are the centers for spreading contagious diseases. The former offers especially dangerous facilities for scattering disease germs. Great pains, therefore, should be taken to exclude pupils attacked by or recovering from diphtheria, scarlet fever, whooping cough, etc., and even those who live in houses where such sickness exists. 6. In our houses [Footnote: The air of our homes is often contaminated by decaying vegetables and other filth in the cellar; by bad air drawn up from the soil into the cellar, by the powerful draughts that our fires create; by defective gas and waste pipes that let the foul air from cesspool or sewer spread through the house; and by piles of refuse, or puddles of slops emptied at the back door. Too often, also, the water in our wells, or in the streams that supply our towns and cities, receives the drainage from outhouses and barnyards, and so introduces into our systems, in the liquid--and thus easily assimilated--form, the most dangerous poisons. The question of sanitary precautions is one that presses upon every observant mind, and demands constant and thoughtful attention. (See p. 305.)] open fireplaces are efficient ventilators, and they should never be closed for any cause. Fresh air admitted by a hot-air register and impure air passed out by a chimney, form a simple and thorough system. Our sleeping apartments demand especial care. As soon as the occupants leave the room, the bedclothes should be removed, and laid on the backs of chairs to air; the bed be shaken up; and the windows thrown open. In the summer, the windows may be closed before the sun is high; the house is then left filled with the cool morning air. In damp and cold weather, a fire should be lighted in sleeping apartments, particularly if used by children [Footnote: In winter, children should always be given a moderately warm, well-ventilated bedroom, with light, fleecy bed coverings. Says a recent English writer: "The loving care which prescribes for children a cold bedroom and a hot, sweltering bed is of the nature that kills. Buried in blankets, their delicate skins become overheated and relaxed, while they are irritated by perspiration; at the same time, the most delicate tissues of all, in the lungs, are dealing with air abnormally frigid. The poor little victims of combined ignorance and kindness thus toss and dream, feverish and troubled, under a mass of bedclothes, while the well-meaning mother, soothed by a bedroom fire, slumbers peacefully through this working out of the sad process of the 'survival of the fittest.'"] or delicate persons, to dry the bedclothing, and also to prevent a chill on the part of the occupants. It is not necessary to go shivering to bed in order to harden one's constitution. WONDERS OF RESPIRATION.--The perfection of the organs of respiration challenges our admiration. So delicate are they that the least pressure would cause exquisite pain, yet tons of air surge to and fro through their intricate passages, and bathe their innermost cells. We yearly perform at least seven million acts of breathing, inhaling one hundred thousand cubic feet of air, and purifying over three thousand five hundred tons of blood. This gigantic process goes on constantly, never wearies or worries us, and we wonder at it only when science reveals to us its magnitude. In addition, by a wise economy, the process of respiration is made to subserve a second use no less important, and the air we exhale, passing through the organs of voice, is transformed into prayers of faith, songs of hope, and words of social cheer. FIG. 33. [Illustration: A, _the natural position of the internal organs._ B _when deformed by tight lacing Marshall says that the liver and the stomach have, in this way, been forced downward almost as low as the pelvis._] DISEASES, ETC.--1. _Constriction of the Lungs_ is produced by tight clothing. The ribs are thus forced inward, the size of the chest is diminished, and the amount of inhaled air decreased. Stiff clothing, and especially a garment that will not admit of a full breath without inconvenience, will prevent that free movement of the ribs so essential to health. Any infraction of the laws of respiration, even though it be fashionable, will result in diminished vitality and vigor, and will be fearfully punished by sickness and weakness through the whole life. 2. _Bronchitis_ (bron-ki'-tis) is an inflammation (see Inflammation) of the mucous membrane of the bronchial tubes. It is accompanied by an increased secretion of mucus, and consequent coughing. 3. _Pleurisy_ is an inflammation of the pleura. It is sometimes caused by an injury to the ribs, and results in a secretion of water within the membrane. 4. _Pneumonia_ (_pneuma_, breath) is an inflammation of the lungs, affecting chiefly the air cells. 5. _Consumption_ is a disease which destroys the substance of the lungs. Like other lung difficulties, it is caused largely by a want of pure air, a liberal supply of which is the best treatment that can be prescribed for it. [Footnote: If I were seriously ill of consumption, I would live outdoors day and night, except in rainy weather or midwinter; then I would sleep in an unplastered log house. Physic has no nutriment, gaspings for air can not cure you, monkey capers in a gymnasium can not cure you, stimulants can not cure you. What consumptives want is pure air, not physic, plenty of meat and plenty of bread.--DR. MARSHALL HALL.] 6. _Asphyxia_ (as-fix'-i-a).--When a person is drowned, strangled, or choked in any way, what is called asphyxia occurs. The face turns black; the veins become turgid; insensibility and often convulsions ensue. If relief is not secured within a few minutes, death will be inevitable. [Footnote: The lack of oxygen, and the presence of carbonic-acid gas, are the combined causes. Oxygen starvation and carbonic-acid poisoning, each fatal in itself, work together to destroy life.] (See p. 264.) 7. _Diphtheria_ (_diphthera_, a membrane) is characterized by fever, debility, and a peculiar sore throat, in which exuding fibrinous matter forms a grayish white membrane, which afterward decomposes with a fetid odor. Its sudden and insidious approach, contagious character, and frequent fatality, render it an exceedingly dreaded disease. A diphtheritic patient should be quarantined, and everything connected with the sick room thoroughly disinfected. 8. _Croup_, which often attacks young children, is an inflammation of the mucous membrane of the larynx and trachea. It is commonly preceded by a cold. The child sneezes, coughs, and is hoarse, but the attack frequently comes on suddenly, and usually in the night. It is accompanied by a peculiar "brassy," ringing cough, which, once heard, can never be mistaken. It may prove fatal within a few hours. (See p. 260.) 9. _Stammering_ depends, not on defects of the muscles, but on a want of due control of the mind. When a stammerer is not too conscious of his lack, and tries to form his words slowly, he speaks plainly, and may sing well, for then his words must follow one another in rhythmic time. Many persons who stammer in common conversation can talk with fluency when making a speech. The stammerer should seek to discover the cause of his difficulty, and to overcome it by vocal and respiratory exercise, especially by speaking only after a full inspiration, and during a long, slow expiration. PRACTICAL QUESTIONS. 1. What is the philosophy of "the change of voice" in a boy? 2. Why can we see our breath on a frosty morning? 3. When a law of health and a law of fashion conflict, which should we obey? 4. If we use a "bunk" bed, should we pack away the clothes when we first rise in the morning? 5. Why should a clothespress be well ventilated? 6. Should the weight of our clothing hang from the waist, or the shoulder? 7. Describe the effects of living in an overheated room. 8. What habits impair the power of the lungs? 9. For full, easy breathing in singing, should we use the diaphragm and lower ribs, or the upper ribs alone? 10. Why is it better to breathe through the nose than the mouth? 11. Why should not a speaker talk while returning home on a cold night after a lecture? 12. What part of the body needs the loosest clothing? 13. What part needs the warmest? 14. Why is a "spare bed" generally unhealthful? 15. Is there any good in sighing? 16. Should a hat be thoroughly ventilated? How? 17. Why do the lungs of people who live in cities become of a gray color? 18. How would you convince a person that a bedroom should be aired? [Footnote: "If the condensed breath collected on the cool windowpanes of a room where a number of persons have been assembled, be burned, a smell as of singed hair will show the presence of organic matter; and if the condensed breath be allowed to remain on the windows for a few days, it will be found, on examination by the microscope, that it is alive with animalculæ."] 19. What persons are most liable to catarrhs, consumption, etc.? 20. If a person is plunged under water, will it enter his lungs? 21. Are bed curtains healthful? 22. Why do some people take "short breaths" after a meal? 23 What is the special value of public parks? 24. Can a person become used to bad air, so that it will not injure him? 25. Why do we gape when we are sleepy? 26. Is a fashionable waist a model of art in sculpture or painting? 27. Should a fireplace be closed? [Footnote: Thousands of lives would be saved if all fireplaces were kept open. If you are so fortunate as to have a fireplace in your room, paint it when not in use, put a bouquet of fresh flowers in it every morning, if you please, or do anything to make it attractive, but never _close it_; better use the fireboards for kindling wood. It would be scarcely more absurd to take a piece of elegantly-tinted court-plaster and stop up the nose, trusting to the accidental opening and shutting of the mouth for fresh air, because you thought it spoiled the looks of your face to have two such great, ugly holes in it, than to stop your fireplace with elegantly-tinted paper, or a Japanese fan, because it looks better.--Leeds.] 28. Why does embarrassment or fright cause a stammerer to stutter still more painfully? 29. In the organs of voice, what parts have somewhat the same effect as the case of a violin and the sounding-board of a piano? 30. Why should we be careful not to "take the breath of a sick person"? 31. What special care should be taken with regard to keeping a cellar clean? 32. How is the air strained as it passes into the lungs? 33. Can one really "draw the air into his lungs"? 34. How often do we breathe? 35. Describe some approved method of ventilation. 36. What is at once the floor of the chest and the roof of the abdomen? 37. What would you do in a case of apparent death by drowning, or by coal gas? (See p. 264.) 38. What would you do in a case of croup, while the doctor was coming? (See p. 260.) 39. How would you treat a severe burn? (See p. 257.) 40. Describe the various ways in which the water in a well is liable to become unwholesome. FIG. 34. [Illustration] V. THE CIRCULATION. "No rest this throbbing slave may ask, Forever quivering o'er his task, While far and wide a crimson jet Leaps forth to fill the woven net, Which in unnumber'd crossing tides The flood of burning life divides, Then, kindling each decaying part, Creeps back to find the throbbing heart." HOLMES. ANALYSIS OF THE CIRCULATION _ _ | 1. Its Composition. | 1. THE BLOOD | 2. Its Uses. | | 3. Transfusion. | |_4. Coagulation | _ | | 1. _Description._ | | 2. _Movements._ | | 3. _Auricles and Ventricles._ | _ | _ | | 1. The | | a. Need of. | | Heart.| | b. Tricuspid and | | | | Bicuspid. | | | 4. _The | c. The Strengthen- | | | Valves._ | ing of the | | | | Valves. | | | | d. Semilunar | | |_ |_ Valves. | | _ | 2. ORGANS OF THE | 2. The | 1. _Description._ | CIRCULATION | Arteries | 2. _The Arterial System._ | | |_3. _The Pulse._ | | _ | | 3. The | 1. _General Description._ | | Veins |_2. _Valves._ | | _ | | 4. The | 1. _Description._ | | Capilla-| 2. _Use._ | |_ ries |_3. _Under the Microscope._ | _ | | 1. The Lesser. | 3. THE CIRCULATION.| 2. The Greater. | |_3. The Velocity of the Blood. | _ | 4. THE HEAT OF THE | 1. Distribution. | BODY. |_2. Regulation. | | 5. LIFE BY DEATH. | | 6. CHANGE OF OUR BODIES. | | 7. THE THREE VITAL ORGANS. | | 8. WONDERS OF THE HEART. | _ | | 1. Description | 9. THE LYMPHATIC | 2. The Glands. | CIRCULATION. | 3. The Lymph. | |_4. The Office of the Lymphatics. | _ | | 1. Congestion. | | 2. Inflammation. | | 3. Bleeding. | 10. DISEASES. | 4. Scrofula. | | 5. A Cold. | |_6. Catarrh. | _ | | 1. Effect of Alcohol upon the Circulation. | 11. ALCOHOLIC | 2. Effect of Alcohol upon the Heart. | DRINKS AND | 3. Effect of Alcohol upon the Membrane. |_ NARCOTICS. | 4. Effect of Alcohol upon the Blood. |_5. Effect of Alcohol upon the Lungs. THE CIRCULATION. THE ORGANS OF THE CIRCULATION are the _heart_, the _arteries_, the _veins_, and the _capillaries_. FIG. 35. [Illustration: A, _corpuscles of human blood, highly magnified;_ B, _corpuscles in the blood of an animal (a non mammal)._] THE BLOOD is the liquid by means of which the circulation is effected. It permeates every part of the body, except the cuticle, nails, hair, etc. The average quantity in each person is about eighteen pounds. [Footnote: It is difficult to estimate the exact amount, and therefore authorities disagree. Foster places it at about one thirteenth of the body weight.] It is composed of a thin, colorless liquid, the _plasma_, filled with red disks or cells, [Footnote: There is also one white globular cell to every three or four hundred red ones. The blood is no more red than the water of a stream would be if you were to fill it with little red fishes. Suppose the fishes to be very, very small--as small as a grain of sand-- and closely crowded together through the whole depth of the stream; the water would look quite red, would it not? And this is the way in which, blood looks red--only observe one thing; a grain of sand is a mountain in comparison with the little red fishes in the blood. If I were to tell you they measured about 1/3500 of an inch in diameter, you would not be much wiser; so I prefer saying (by way of giving you a more perfect idea of their minuteness) that there would be about a million in such a drop of blood as would hang on the point of a needle. I say so on the authority of a scientific microscopist--M. Bouillet. Not that he has ever counted them, as you may suppose, any more than I have done; but this is as near an approach as can be made by calculation to the size of 1/3500 part of an inch in diameter.--JEAN MACE.] so small that about three thousand five hundred placed side by side would measure only an inch, and it would take sixteen thousand laid flatwise upon one another to make a column of that height. Under the microscope, they are found to be rounded at the edge and concave on both sides. [Footnote: By pricking the end of the finger with a needle, we can obtain a drop for examination. Place it on the slide, cover with a glass, and put it at once under the microscope. The red disks will be seen to group themselves in rows, while the white disks will seem to draw apart, and to be constantly changing their form. After a gradual evaporation, the crystals (Fig. 36) may be seen. In animals, they have various, though distinctive forms.] They have a tendency to collect in piles like rolls of coin. The size and shape vary in the blood of different animals. [Footnote: Authorities differ greatly in their estimate of the size of the disks (corpuscles) in human blood. The fact is that the size varies in different persons, probably also in the same individual. Many of the best microscopists therefore hesitate to state whether a particular specimen of blood belonged to a human being or to an animal. Others claim that they can distinguish with accuracy. Evidently, the question is one of great uncertainty. The following statement of the size of the cells in different animals is taken from Gulliver's tables: Cat, 1/4404 of an inch in diameter; whale, 1/3100; mouse, 1/3614; hog, 1/4230; camel, 1/3123; sheep, 1/3352; horse, 1/4800; Virginia deer, 1/5038; dog- faced baboon, 1/4861; brown baboon, 1/3493; red monkey, 1/3396; black monkey, 1/3530.] Disks are continually forming in the blood, and are constantly dying--twenty million at every breath.--DRAPER. The plasma also contains fibrin, [Footnote: it is usual to say that fibrin is contained in the blood. It probably does not exist as such, but there are present in the blood certain substances known as _paraglobulin_ and _fibrinogen_, which by the action of a third substance, _fibrin ferment_ under certain circumstances, form fibrin and so cause coagulation. The exact nature of the process by which fibrin is produced by these three factors is not understood--See Foster's _Text Book of Physiology_, p 22.] albumin--which is found nearly pure in the white of an egg--and various mineral substances, as iron, [Footnote: Enough iron has been found in the ashes of a burned body to form a mourning ring.] lime, magnesia, phosphorus, potash, etc. FIG. 36. [Illustration: _Blood Crystals_] USES OF THE BLOOD.--The blood has been called "liquid flesh"; but it is more than that, since it contains the materials for making every organ. The plasma is rich in mineral matter for the bones, and in albumen for the muscles. The red disks are the air cells of the blood. They contain the oxygen so essential to every operation of life. Wherever there is work to be done or repairs to be made, there the oxygen is needed. It stimulates to action, and tears down all that is worn out. In this process, it combines with and actually burns out parts of the muscles and other tissues, as wood is burned in the stove. [Footnote: For the sake of simplicity, perhaps to conceal our own ignorance, we call this process "burning." The simile of a fire is good so far as it goes. But as to the real nature of the change which the physiologist briefly terms "oxidation," we know nothing. This much only can be asserted positively. A stream of oxygen is carried by the blood to the muscles (in fact to every tissue in the body), while, from the muscles the blood carries away a stream of carbonic acid and water. But what takes place in the muscles, when and what chemical change occurs, no one can tell. We see the first and the last stage. We know that contraction of the muscles somehow comes about, oxygen disappears, carbonic acid appears, energy is released, and force is exhibited as motion, heat, and electricity. But the intermediate step is hidden. There are certain theories advanced, however, that are worth considering. Some physiologists hold that the muscle has the power of taking up the oxygen from the _hemoglobin_ (a body that comprises ninety per cent of the red corpuscles when dried, and is the oxygen carrier of the blood), and fixing it, as well as the raw material (food) furnished by the blood, thus forming a true contractile substance. The breaking down or decomposition of this contractile substance in the muscle, sets free its potential energy. The process is gentle so long as the muscle is at rest, but becomes excessive and violent when contraction occurs. (See "Foster's Physiology," p. 118.) It is also believed by some that the chemical change in the muscle partakes of a fermentive character; that, under the influence of the proper ferments, the substances break up into other and simpler products, thus setting free heat and force; and that this chemical change is followed by a secondary oxidation by the oxygen in the arterial blood, thereby forming carbonic acid and water, as in all putrefactive processes. But these and other views are not as yet fully understood; while they utterly fail to tell us how a collection of simple cells, filled merely with a semifluid mass of matter, can contract and set free muscular power. The commonness of this act hides from us its wonderful nature. But here, hidden in the cell--Nature's tiny laboratory--lies the mystery of life. Before its closed door we ponder in vain, confessing the unskillfulness of our labor, and fearing all the while lest the _Secret of the Cell_ will always elude our search.] The blood, now foul with the burned matter, the refuse of this fire, is caught up by the circulation, and whirled back to the lungs, where it is purified, and again sent bounding on its way. There are then two different kinds of the blood in the body: the red or arterial, and the dark or venous. TRANSFUSION.--As the blood is really the "vital fluid" it would seem that feeble persons might be restored to vigor by infusing healthy blood into their veins. This hypothesis, so valuable in its possible results in prolonging human life, has been carefully tested. Animals which have ceased to breathe have thus had their vitality recalled. In the seventeenth century the theory became a subject of special investigation. A maniac was restored to reason by the blood of a calf, and the most extravagant hopes were entertained. But many fatal accidents occurring, experiments upon human beings were forbidden by law, and transfusion soon fell into disuse. It has, however, been successfully practiced in several cases within the last few years, and is a method still in repute for saving lives. COAGULATION.--When blood is exposed to the air, it coagulates. This is caused by the solidifying of the fibrin, which entangling the disks, forms the "clot." The remaining clear, yellow liquid is the _serum_. The value of this peculiar property of the blood can hardly be overestimated. The coagulation soon checks all ordinary cases of bleeding. [Footnote: In the case of the lower animals, which have no means of stopping hemorrhages as we have, the coagulation is generally still more rapid. In some species of birds it takes place almost instantaneously.] When a wound is made, and bleeding commences, the fibrin forms a temporary plug, as it were, which is absorbed when the healing process is finished. Thus we see how a Divine foresight has provided not only for the ordinary wants of the body, but also for the accidents to which it is liable. [Footnote: The fibrin is not an essential ingredient of the blood. All the functions of life are regularly performed in people whose blood lacks fibrin; and, in cases of transfusion, where blood deprived of its fibrin was used, the vivifying influence seemed to be the same. Its office, therefore, must mainly be to stanch any hemorrhage which may occur.--FLINT.] FIG. 37. [Illustration: _The Heart._ A, _the right ventricle;_ B, _the left ventricle;_ C, _the right auricle;_ D, _the left auricle._] THE HEART is the engine which propels the blood. It is a hollow, pear- shaped muscle, about the size of the fist. It hangs, point downward, just to the left of the center of the chest. (See Fig. 31.) It is inclosed in a loose sac of serous membrane, [Footnote: The mucous membrane lines the open cavities of the body; the serous, the closed. The pericardium is a sac composed of two layers--a fibrous membrane on the outside, and a serous one on the inside. The latter covers the external surface of the heart, and is reflected back upon itself in order to form, like all the membranes of this nature, a sac without an opening. The heart is thus covered by the pericardial sac, but not contained inside its cavity. A correct idea may be formed of the disposition of the pericardium around the heart by recalling a very common and very convenient, though now discarded headdress, the cotton nightcap. The pericardium incloses the heart exactly as this cap covered the heads of our forefathers.-- _Wonders of the Human Body_.] called the pericardium (_peri_, about; and _kardia_, the heart). This secretes a lubricating fluid, and is smooth as satin. THE MOVEMENTS OF THE HEART consist of an alternate contraction and expansion. The former is called the _sys'-to-le_, and the latter the _di-as'-to-le_. During the diastole, the blood flows into the heart, to be expelled by the systole. The alternation of these movements constitutes the beating of the heart which we hear so distinctly between the fifth and sixth ribs. [Footnote: Two sounds are heard if we put our ear over the heart,--the first and longer as the blood is leading the organ, the second as it falls into the pockets of the two arteries, and the valves then striking together cause it. The first sound is mainly the noise made by the muscular tissue. During the first, the two ventricles contract; during the second the two auricles do so. The hand may feel the heart striking the ribs as it contracts,--a feeling called the impulse, or, if quicker and stronger than usual, palpitation. This is not always a sign of disease, but in hypochondriacs is often an effect of the mind on the nerves of the heart.--MAPOTHER] FIG. 38. [Illustration: _Chambers of the Heart_ A, _right ventricle;_ B, _left ventricle,_ C, _right auricle,_ D, _left auricle,_ E, _tricuspid valve,_ F, _bicuspid valve;_ G, _semilunar valves,_ H, _valve of the aorta;_ I, _inferior vena cava,_ K, _superior vena cava,_ L, L, _pulmonary veins._] THE AURICLES AND VENTRICLES--The heart is divided into four chambers. In an adult, each holds about a wineglassful. The upper ones, from appendages on the outside resembling the ears of a dog, are called _auricles (aures_, ears). are termed _ventricles_. The auricle and ventricle on each side communicate with each other, but the right and left halves of the heart are entirely distinct, and perform different offices. The left side propels the red blood; and the right, the dark. The auricles are merely reservoirs to receive the blood (the left auricle, as it filters in bright and pure from the lungs; the right, as it returns dark and foul from the tour of the body), and to furnish it to the ventricles as they need. Their work being so light, their walls are comparatively thin and weak. On the other hand, the ventricles force the blood (the left, to all parts of the body; the right, to the lungs), and are, therefore, made very strong. As the left ventricle drives the blood so much farther than the right, it is correspondingly thicker and stronger. NEED OF VALVES IN THE HEART.--As the auricles do not need to contract with much force simply to empty their contents into the ventricles below them, there is no demand for any special contrivance to prevent the blood from setting back the wrong way. Indeed, it would naturally run down into the ventricle, which is at that moment open to receive it. But, when the strong ventricles contract, especially the left one, which must drive the blood to the extremities, some arrangement is necessary to prevent it from returning into the auricle. Besides, when they expand, the "suction power" would tend to draw back again from the arteries all the blood just forced out. This difficulty is obviated by means of little doors, or valves, which will not let it go the wrong way. [Footnote: The heart of an ox or a sheep may be used to show the chambers and valves. The aorta should be cut as far as possible from the heart, and then by pumping in water the perfection of these valves will be finely exhibited. Cutting the heart across near the middle will show the greater thickness of the left ventricle.] THE TRICUSPID AND BICUSPID VALVES.--At the opening into the right ventricle, is a valve consisting of three folds or flaps of membrane, whence it is called the _tricuspid_ valve (_tri_, three; and _cuspides_, points), and in the left ventricle, one containing two flaps, and named the _bicuspid_ valve. These hang so loosely as to oppose no resistance to the passage of the blood into the ventricles; but, if any attempts to go the other way, it gets between the flaps and the walls of the heart, and, driving them outward, closes the orifice. FIG. 39. [Illustration: _Diagram showing the peculiar Fibrous Structure of the Heart and the Shape of the Valves._ A, _tricuspid valve,_ B, _bicuspid valve;_ C, _semilunar valves of the aorta;_ D, _semilunar valves of the pulmonary artery._] THESE FLAPS ARE STRENGTHENED like sails by slender cords, which prevent their being pressed back through the opening. If the cords were attached directly to the walls of the heart, they would be loosened in the systole, and so become useless when most needed. They are, therefore, fastened to little muscular pillars projecting from the sides of the ventricle; when that contracts, the pillars contract also, and thus the cords are held tight. THE SEMILUNAR VALVES.--In the passages outward from the ventricles, are valves, called from their peculiar half-moon shape _semilunar_ valves (_semi_, half; _Luna_, Moon). Each consists of three little pocket-shaped folds of membrane, with their openings in the direction which the blood is to take. When it sets back, they fill, and, swelling out, close the passage (Fig. 40). THE ARTERIES [Footnote: _Aer,_ air; and _tereo,_ I contain--so named because after death they contain air only, and hence the ancients supposed them to be air tubes leading through the body.] are the tube-like canals which convey the blood _from_ the heart. They carry the red blood (see note, p. 119). They are composed of an elastic tissue, which yields at every throb of the heart, and then slowly contracting again, keeps up the motion of the blood until the next systole. The elasticity of the arteries acts like the air chamber of a fire engine, which converts the intermittent jerks of the brakes or pump into the steady stream of the hose nozzle. The arteries sometimes communicate by means of branches or by meshes of loops, so that if the blood be blocked in one, it can pass round through another, and so get by the obstacle. [Footnote: This occurs especially about the joints, where it serves to maintain the circulation during the bending of a limb, or when the main artery is obstructed by disease or injury, or has been tied by the surgeon. In the last case, the small adjacent arteries gradually enlarge, and form what is called a collateral circulation.] When an artery penetrates a muscle, it is often protected by a sheath or by fibrous rings, which prevent its being pulled out of place or compressed by the play of the muscles. The arteries are generally located as far as possible beneath the surface, out of harm's way, and hence are found closely hugging the bones or creeping through safe passages provided for them. They are generally nearly straight, and take the shortest routes to the parts which they are to supply with blood. THE ARTERIAL SYSTEM starts from the left ventricle by a single trunk--the _aorta_--which, after giving off branches to the head, sweeps back of the chest with a bold curve--the _arch of the aorta_ (_c_, Fig. 34)--and thence runs downward (_f_), dividing and subdividing, like a tree, into numberless branches, which, at last, penetrate every nook and corner of the body. THE PULSE.--At the wrist (_k_, radial artery) and on the temple (temporal artery) we can feel the expansion of the artery by each little wave of blood set in motion by the contraction of the heart. In health, there are about seventy-two [Footnote: This number varies much with age, sex, and individuals. Napoleon's pulse is said to have been only forty, while it is not infrequent to find a healthy pulse at one hundred or over. In general, the pulse is quicker in children and in old people than in the middle-aged; in short persons than in tall; in women than in men. Shame makes the heart send more blood to the blushing cheek, and fear almost stops it. The will can not check the heart. There is said, however, to have been a notable exception to this in the case of one Colonel Townsend, of Dublin, who, after having succeeded several times in stopping the pulsation, at last lost his life in the act.] pulsations per minute. They increase with excitement or inflammation, weaken with loss of vigor, and are modified by nearly every disease. The physician, therefore, finds the pulse a good index of the state of the system and the character of the disorder. (See p. 314.) THE VEINS are the tube-like canals which convey the blood _to_ the heart. [Footnote: There is one exception to the general course of the veins. The _portal_ vein carries the blood from the digestive organs to the liver, where it is acted upon, thence poured into the ascending vena cava, and goes back to the heart.] They carry the dark or venous blood (note, p. 119). As they do not receive the direct impulse of the heart, their walls are made much thinner and less elastic than those of the arteries. At first small, they increase in size and diminish in number as they gradually pour into one another, like tiny rills collecting to form two rivers, the vena cava ascending and the vena cava descending (_l, m_, Fig. 34), which empty into the right auricle. Some of the veins creep along under the skin, where they can be seen, as in the back of the hand; while others accompany the arteries, some of which have two or more of these companions. VALVES similar in construction to those already described (the semilunar valves of the heart, page 114) are placed at convenient intervals, in order to guide the blood in its course, and prevent its setting backward. [Footnote: Too much standing, or tight elastics, often cause the veins in the leg to swell, so that the valves can not work; the veins then become _varicose_, or permanently enlarged, and, if they burst, the bleeding may be profuse and even dangerous. Raising the leg and pressing the finger on the bleeding spot will stay it. Walking does not encourage this disease, for the active muscles force on the venous blood. Clerks who are subject to varicose veins should have seats behind the counters where they may rest when not actually employed. A deep breath helps the flow in the veins, and a wound may suck in air with fatal effect. A maimed horse is most mercifully killed by blowing a bubble of air into the veins of his neck. As the deep-sea pressure would burst valves, the whale has none; hence a small wound by the harpoon causes him to bleed to death.-- MAPOTHER.] We can easily examine the working of these valves. On baring the arm, blue veins may be seen running along the arm toward the hand. Their diameter is tolerably even, and they gradually decrease in size. If now the finger be pressed on the upper part of one of these veins, and then passed downward so as to drive its blood backward, swellings like little knots will make their appearance. Each of these marks the location of a valve, which is closed by the blood we push before our finger. Remove the pressure, and the valve will swing open, the blood set forward, and the vein collapse to its former size. FIG. 40. [Illustration: _Valves of the Veins._] THE CAPILLARIES (_capillus,_ a hair) form a fine network of tubes, connecting the ends of the arteries with the veins. They blend, however, with the extremities of these two systems, so that it is not easy to tell just where an artery ends and a vein begins. So closely are they placed, that we can not prick the flesh with a needle without injuring, perhaps, hundreds of them. The air cells of the blood deposit there their oxygen, and receive carbonic acid, while in the delicate capillaries of the lungs [Footnote: The capillary tubes are there so fine that the disks of the blood have to go one by one, and are sadly squeezed at that. However, their elasticity enables them to resume their old shape as soon as they have escaped from this labyrinth.] they give up their load of carbonic acid in exchange for oxygen. FIG. 41. [Illustration: _Circulation of the Blood in the Web of a Frog's Foot, highly magnified._ A, _an artery;_ B, _capillaries crowded with disks, owing to a rupture just above, where the disks are jammed into an adjacent mesh;_ C, _a deeper vein; the black spots are pigment cells._] If, by means of a microscope, we examine the transparent web of a frog's foot, we can trace the route of the blood. [Footnote: With small splints and twine, a frog's foot can be easily stretched and tied so that the transparent web can be placed on the table of the microscope.] It is an experiment of wonderful interest. The crimson stream, propelled by the heart, rushes through the arteries, until it reaches the intricate meshes of the capillaries. Here it breaks into a thousand tiny rills. We can see the disks winding in single file through the devious passages, darting hither and thither, now pausing, swaying to and fro with an uncertain motion, and anon dashing ahead, until, at last, gathered in the veins, the blood sets steadily back on its return to the heart. THE CIRCULATION [Footnote: The circulation of the blood was discovered by Harvey in 1619. For several years, he did not dare to publish his belief. When it became known, he was bitterly persecuted, and his practice as a physician greatly decreased in consequence. He lived, however, to see his theory universally adopted, and his name honored. Harvey is said to have declared that no man over forty years of age accepted his views.] consists of two parts--the _lesser_, and the _greater_. FIG. 42. [Illustration: _Diagram illustrating the Circulation of the Blood._-- MARSHALL. A, _vena cava descending (superior);_ Z, _vena cava ascending (inferior);_ C, _right auricle;_ D, _right ventricle;_ E, _pulmonary artery;_ F P, _lungs and pulmonary veins;_ G, _left auricle;_ H, _left ventricle;_ I, K, _aorta._] 1. _The Lesser Circulation_.--The dark blood from the veins collects in the right auricle, and, going through the tricuspid valve, empties into the right ventricle. Thence it is driven past the semilunar valves, through the pulmonary artery, to the lungs. After circulating through the fine capillaries of the air cells contained in the lungs, it is returned, bright and red, through the four pulmonary veins, [Footnote: It is noticeable that the pulmonary set of veins circulates red blood, and the pulmonary set of arteries circulates dark blood. Both are connected with the lungs.] to the left auricle. 2. _The Greater Circulation_.--From the left auricle, the blood is forced past the bicuspid valve to the left ventricle; thence it is driven through the semilunar valves into the great aorta, the main trunk of the arterial system. Passing through the arteries, capillaries, and veins, it returns through the venæ cavæ, ascending and descending, gathers again in the right auricle, and so completes the "grand round" of the body. Both these circulations are going on constantly, as the two auricles contract, and the two ventricles expand simultaneously, and _vice versa_. THE VELOCITY OF THE BLOOD varies so much in different parts of the body, and is influenced by so many circumstances, that it can not be calculated with any degree of accuracy. It has been estimated that a portion of the blood will make the tour of the body in about twenty-three seconds (FLINT), and that the entire mass passes through the heart in from one to two minutes. [Footnote: The total amount of blood in an adult of average weight is about eighteen pounds. Dividing this by five ounces, the quantity discharged by the left ventricle at each systole, gives fifty- eight pulsations as the number necessary to transmit all the blood in the body. This, however, is an extremely unreliable basis of calculation, as the rapidity of the blood is itself so variable. Chauvreau has shown by experiments with his instrument that, corresponding to the first dilation of the vessels, the blood moves with immense rapidity; following this, the current suddenly becomes nearly arrested; this is succeeded by a second acceleration in the current, not quite so rapid as the first; and after this there is a gradual decline in the rapidity to the time of the next pulsation.] (See p. 314.) DISTRIBUTION AND REGULATION OF THE HEAT OF THE BODY.--1. _Distribution_.--The natural temperature is not far from 98°. [Footnote: The average temperature is, however, easily departed from. Through some trivial cause the cooling agencies may be interfered with, and then, the heating processes getting the superiority, a high temperature or fever comes on. Or the reverse may ensue. In Asiatic cholera, the constitution of the blood is so changed that its disks can no longer carry oxygen into the system, the heat-making processes are put a stop to, and, the temperature declining, the body becomes of a marble coldness, characteristic of that terrible disease.--DRAPER.] This is maintained, as we have already seen, by the action of the oxygen within us. Each capillary tube is a tiny stove, where oxygen is combining with the tissues of the body (see note, p. 107). Every contraction of a muscle develops heat, the latent heat being set free by the breaking up of the tissue. The warmth so produced is distributed by the circulation of the blood. Thus the arteries, veins, and capillaries form a series of hot- water pipes, through which the heated liquid is forced by a pump--the heart--while the heat is kept up, not by a central furnace and boiler, but by a multitude of little fires placed here and there along its course. 2. _Regulation_.--The temperature of the body is regulated by means of the pores of the skin and the mucous membrane in the air passages. When the system becomes too warm, the blood vessels on the surface expand, the blood fills them, the fluid exudes into the perspiratory glands, pours out upon the exterior, and by evaporation cools the body. [Footnote: Just as water sprinkled on the floor cools a room.--_Popular Physics_, p. 255.] When the temperature of the body is too low, the vessels contract, less blood goes to the surface, the perspiration decreases, and the loss of heat by evaporation diminishes. [Footnote: Thus one is enabled to go into an oven where bread is baking, or into the arctic regions where the mountains are snow and the rivers ice. Even by these extremes the temperature of the blood will be but slightly affected. In the one case, the flood gates of perspiration will be opened and the superfluous heat expended in turning the water to vapor; and, in the other, they will be tightly closed and all the heat retained.] LIFE BY DEATH.--The body is being incessantly corroded, and portions borne away by the tireless oxygen. The scales of the epidermis are constantly falling off and being replaced by secretion from the cutis. The disks of the blood die, and new ones spring into being. On the continuance of this interchange depend our health and vigor. Every act is a destructive one. Not a bend of the finger, not a wink of the eye, not a thought of the brain but is at some expense of the machine itself. Every process of life is thus a process of death. The more rapidly this change goes on, and fresh, vigorous tissue takes the place of the old, the more elasticity and strength we possess. CHANGE OF OUR BODIES.--There is a belief that our bodies change once in seven years. From the nature of the case, the rate must vary with the labor we perform; the organs most used altering oftenest. Probably the parts of the body in incessant employment are entirely reorganized many times within a single year. [Footnote: To use a homely simile, our bodies are like the Irishman's knife, which, after having had several new blades, and at least one new handle, was yet the same old knife.] THE THREE VITAL ORGANS.--Death is produced by the stoppage of the action of any one of the three organs--the heart, the lungs, or the brain. They have, therefore, been termed the "Tripod of Life." Really, however, as Huxley has remarked, "Life has but two legs to stand upon." If respiration and circulation be kept up artificially, the removal of the brain will not produce death. [Footnote: When death really does take place, _i. e._, when the vital organs are stopped, it is noticeable that the tissues do not die for some time thereafter. If suitable stimulants be applied, as the galvanic battery, transfusion of blood, etc., the muscles may be made to contract, and many of the phenomena of life be exhibited. Dr. Brown- Sequard thus produced muscular action in the hand of a criminal, fourteen hours after his execution.] WONDERS OF THE HEART.--The ancients thought the heart to be the seat of love. There were located the purity and goodness as well as the evil passions of the soul. [Footnote: Our common words, hearty, large-hearted, courage (_cor_, the heart), are remains of this fanciful theory.] Modern science has found the seat of the mental powers to be in the brain. But while it has thus robbed the heart of its romance, it has revealed wonders which eclipse all the mysteries of the past. This marvelous little engine throbs on continually at the rate of one hundred thousand beats per day, forty millions per year, often three billions without a single stop. It is the most powerful of machines. "Its daily work is equal to one third that of all the muscles. If it should expend its entire force in lifting its own weight vertically, it would rise twenty thousand feet in an hour." [Footnote: "The greatest exploit ever accomplished by a locomotive, was to lift itself through less than one eighth of that distance." Vast and constant as is this process, so perfect is the machinery, that there are persons who do not even know where the heart lies until disease or accident reveals its location.] Its vitality is amazing. The most tireless of organs while life exists, it is one of the last to yield when life expires. So long as a flutter lingers at the heart, we know the spark of being is not quite extinguished, and there is hope of restoration. During a life such as we sometimes see, it has propelled half a million tons of blood, yet repaired itself as it has wasted, during its patient, unfaltering labor. The play of its valves and the rhythm of its throb have never failed until, at the command of the great Master Workman, the "wheels of life have stood still." [Footnote: Our brains are seventy-five- year clocks. The Angel of Life winds them up once for all, then closes the case, and gives the key into the hand of the Angel of the Resurrection. Ticktack! Ticktack! go the wheels of thought; our will can not stop them, they can not stop themselves; sleep can not stop them; madness only makes them go faster; death alone can break into the case, and, seizing the ever-swinging pendulum which we call the heart, silence at last the clicking of the terrible escapement we have carried so long beneath our wrinkled foreheads.--HOLMES.] FIG. 43. [Illustration: _Lymphatics of the Head and Neck, showing the Glands, and,_ B, _the thoracic duct as it empties into the left innominate vein at the junction of the left jugular and subclavian veins._] THE LYMPHATIC CIRCULATION is intimately connected with that of the blood. It is, however, more delicate in its organization, and less thoroughly understood. Nearly every part of the body is permeated by a second series of capillaries, closely interlaced with the blood capillaries already described, and termed the Lymphatic system. The larger number converge into the thoracic duct--a small tube, about the size of a goose quill, which empties into the great veins of the neck (Fig. 43). Along their course the lymphatics frequently pass through _glands_,--hard, pinkish bodies of all sizes, from that of a hemp seed to an almond. These glands are often enlarged by disease, and then are easily felt. _The Lymph_, which circulates through the lymphatics like blood through the veins, is a thin, colorless liquid, very like the serum. This fluid, probably in great measure an overflow from the blood vessels, is gathered up by the lymphatics, undergoes in the glands some process of preparation not well understood, and is then returned to the circulation. FIG. 44. [Illustration: _Lymphatics in the Leg, with Glands at the Hip_.] OFFICE OF THE LYMPHATICS.--It is thought that portions of the waste matter of the body capable of further use are thus, by a wise economy, retained and elaborated in the system. The _lacteals_, a class of lymphatics which will be described under Digestion (p. 166), aid in taking up the food; after a meal they become milk white. In the lungs, the lymphatics are abundant; sometimes absorbing the poison of disease, and diffusing it through the system. [Footnote: Persons have thus been poisoned by tiny particles of arsenic which evaporate from green wall paper, and float in the air.] The lymphatics of the skin we have already spoken of as producing the phenomena of absorption, [Footnote: Pain is often relieved by injecting under the cuticle a solution of morphine, which is taken up by the absorbents, and so carried through the system.] Nature in her effort to heal a cut deposits an excess of matter to fill up the breach. Soon, the lymphatics go to work and remove the surplus material to other parts of the body. Animals that hibernate are supported during the winter by the fat which their absorbents carry into the circulation from the extra supply they have laid up during the summer. In famine or in sickness, a man unconsciously consumes his own flesh. DISEASES, ETC.--l. _Congestion_ is an unnatural accumulation of blood in any part of the body. The excess is indicated by the redness. If we put our feet in hot water, the capillaries will expand by the heat, and the blood will set that way to fill them. The red nose and purplish face of the drunkard show a congestion of the capillaries. Those vessels have lost their power of contraction, and so are permanently increased in size and filled with blood. Blushing is a temporary congestion. The capillaries being expanded only for an instant by the nervous excitement, contract again and expel the blood. [Footnote: Blushing is a purely local modification of the circulation of this kind, and it will be instructive to consider how a blush is brought about. An emotion--sometimes pleasurable, sometimes painful--takes possession of the mind; thereupon a hot flush is felt, the skin grows red, and according to the intensity of the emotion these changes are confined to the cheeks only, or extend to the "roots of the hair," or "all over." What is the cause of these changes? The blood is a red and a hot fluid; the skin reddens and grows hot, because its vessels contain an increased quantity of this red and hot fluid; and its vessels contain more, because the small arteries suddenly dilate, the natural moderate contraction of their muscles being superseded by a state of relaxation. In other words, the action of the nerves which cause this muscular contraction is suspended. On the other hand, in many people, extreme terror causes the skin to grow cold, and the face to appear pale and pinched. Under these circumstances, in fact, the supply of blood to the skin is greatly diminished, in consequence of an excessive stimulation of the nerves of the small arteries, which causes them to contract and so to cut off the supply of blood more or less completely.-- Huxley's _Physiology_.] 2. _Inflammation_ means simply a burning. If there is irritation or an injury at any spot, the blood sets thither and reddens it. This extra supply, both by its presence and the friction of the swiftly moving currents, produces heat. The pressure of the distended vessels upon the nerves frets them, and produces pain. The swelling stretches the walls of the blood vessels, and the serum or lymph oozes through. The four characteristics of an inflammation are redness, heat, pain, and swelling. 3. _Bleeding_, if from an artery, will be of red blood, and will come in jets; [Footnote: The elasticity of the arteries (p. 114) is a physical property, as may easily be shown by removing one from a dead body. If they were rigid and unyielding, a considerable portion of the heart's force would be uselessly expended against their walls. Their expansion is a passive state, and depends on the pressure of the blood within them; but their vital contractility is an active property.--The intermittent movement of the blood through the arteries is strikingly shown in the manner in which they bleed when wounded. When an artery is cut across, the blood spurts out with great force to a distance of several feet, but the flow is not continuous. It escapes in a series of jets, the long, slender scarlet stream rising and falling with each beat of the heart, and this pulsation of the blood stream tells at once that it comes from a wounded artery. But as the blood traverses these elastic tubes, the abruptness of the heart's stroke becomes gradually broken and the current equalized, so that the greater the distance from the heart the less obvious is the pulsation, until at length in the capillaries the rate of the stream becomes uniform.] if from the veins, it will be of dark blood, and will flow in a steady stream. If only a small vessel be severed, it may be checked by a piece of cloth held or bound firmly upon the wound. If a large trunk be cut, especially in a limb, make a knot in a handkerchief and tie it loosely about the limb; then, placing the knot on the limb, with a short stick twist the handkerchief tightly enough to stop the flow. If you have a piece of cloth to use as a pad, the knot will be unnecessary. If it be an artery that is cut, the pressure should be applied between the wound and the heart; if a vein, beyond the wound. If you are alone, and are severely wounded, or in an emergency, like a railroad accident, use the remedy which has saved many a life upon the battlefield--bind or hold a handful of dry earth upon the wound, elevate the part, and await surgical assistance. 4. _Scrofula_ is generally inherited. It is a disease affecting the lymphatic glands, most commonly those of the neck, forming "kernels," as they are called. It is, however, liable to attack any organ. Persons inheriting this disease can hope to ward off its insidious approaches only by the utmost care in diet and exercise; by the use of pure air and warm clothing, and by avoiding late hours and undue stimulus of all kinds. Probably the most fatal and common excitants of the latent seeds of scrofula are insufficient or improper food, and want of ventilation. 5. _A COLD_.--We put on a thinner dress than usual, or, when heated, sit in a cool place. The skin is chilled, and the perspiration checked. The blood, no longer cleansed and reduced in volume by the drainage through the pores, sets to the lungs for purification. That organ is oppressed, breathing becomes difficult, and the extra mucus secreted by the irritated surface of the membrane is thrown off by coughing. The mucous membrane of the nasal chamber sympathizes with the difficulty, and we have "a cold in the head," or a catarrh. In general, the excess of blood seeks the weakest point, and develops there any latent disease [Footnote: A party go out for a walk and are caught in a rain, or, coming home heated from some close assembly, throw off their coats to enjoy the deliciously cool breeze. The next day, one has a fever, another a slight headache, another pleurisy, another pneumonia, another rheumatism, while some of the number escape without any ill feeling whatever. The last had vital force sufficient to withstand the disturbance, but in the others there were various weak points, and to these the excess of blood has gone, producing congestion.] Where one person has been killed in battle, thousands have died of colds. To restore the equipoise must be the object of all treatment. We put the feet in hot water and they soon become red and gorged with the blood which is thus called from the congested organs. Hot footbaths have saved multitudes of lives. It is well in case of a sudden cold to go immediately to bed, and with hot drinks and extra clothing open the pores, and induce free perspiration. This calls the blood to the surface, and, by equalizing and diminishing the volume of the circulation, affords relief. [Footnote: Severe colds may often be relieved in their first stages by using lemons freely during the day, and taking at night fifteen or twenty grains of sodium bromide. Great care, however, should be observed in employing the latter remedy, except under the advice of a physician.] 6. _Catarrh_ commonly manifests itself by the symptoms known as those of a "cold in the head," and is produced by the same causes. It is an inflammation of the mucous membrane lining the nasal and bronchial passages. One going out from the hot dry air of a furnace-heated room into the cold damp atmosphere of our climate can hardly avoid irritating and inflaming this tender membrane. If our rooms were heated less intensely, and ventilated more thoroughly, so that we had not the present hothouse sensitiveness to cold air, this disease would be far less universal, and perhaps would disappear entirely. [Footnote: Dr. Gray gives the following table: ===================================================================== Rooms Occupied by Letter-press Printers. | Number | Subject to | per cent | Catarrh | Spitting | | Blood. | ------------------------------------------+------------+------------- 104 men having less than 500 cubic feet | | of air to breathe | 12.50 | 12.50 | | 115 men having from 500 to 600 cubic feet | | of air to breathe | 4.35 | 3.58 | | 101 men having more than 600 cubic feet | | of air to breathe | 3.96 | 1.98 ---------------------------------------------------------------------] (See p. 315.) ALCOHOLIC DRINKS AND NARCOTICS. 1. ALCOHOL. That we may understand fully the effect of alcohol upon the human system, let us first consider its nature and the process by which harmless fruits and grains are made to produce a substance so unlike themselves in its deleterious effects. HOW ALCOHOL IS MADE.--When any substance containing sugar, as fruit juice, is caused to ferment, the elements of which the sugar is composed, viz., hydrogen, carbon, and oxygen, so rearrange themselves as to form carbon dioxide (carbonic acid), alcohol, and certain volatile oils and ethers. [Footnote: The precise relation between chemical phenomena and the physiological functions of the organic ferment is still to be discovered; and all that has been said, written, and brought forward to decide the question, need experimental proof.--SCHÜTZENBERGER.] The carbonic acid partly evaporates and partly remains in the liquor; the alcohol is the poisonous or intoxicating principle, while the oils and ethers impart the peculiar flavor and odor. Thus wine is fermented grape juice, and cider is fermented apple juice, each having its distinctive taste and smell, and each containing, as one product of fermentation, more or less of the inebriating alcohol. Wines are also made from other fruits and vegetables, such as oranges, currants, tomatoes, and rhubarb, but the alcohol which they contain is of the same nature in all cases, whether the fermented liquor has been manufactured in great quantities, by large presses, or by a simple domestic process for home consumption. It is important to remember this fact, as many people do not associate alcohol with such beverages as domestic wines and home-brewed ales, whereas it is always present with the same treacherous qualities which attach to it everywhere. An apple is a wholesome and useful fruit, and its simple juice, fragrant and refreshing, is a delight to the palate; but apple juice converted into cider and allowed to enter upon alcoholic fermentation, loses its innocence, and becomes a dangerous drink, because it is the nature of the alcohol it now contains to create an appetite for more alcohol. (See p. 185.) WHAT IS A FERMENT?--Ferments, of which there are many varieties in nature, are minute living organisms analogous to the microscopic objects called bacteria or microbes, [Footnote: There is no well-defined limit between ferments and bacteria, any more than between ferments and fungi, or again, between fungi and bacteria. Their smaller size is the principal difference which separates bacteria from ferments, although there are bacteria of large size, such as are so frequently found in the mouth of even a healthy man, and which much resemble in their mode of growth some of the lower fungi.--Trouessart.] of which we have heard much in late years, especially in connection with the famous researches and experiments of the great French investigator, M. Pasteur. He tells us that "Every fermentation has its specific ferment. This minute being produces the transformation which constitutes fermentation by breathing the oxygen of the substance to be fermented, or by appropriating for an instant the whole substance, then destroying it by what may be termed the secretion of the fermented products." [Footnote: What we call spontaneous fermentation often occurs, as when apple juice turns to hard cider by simple exposure to the air. Science teaches us, however, that this change is always effected by the action of the busy little ferments which, wandering about, drop into the liquid, begin their rapid propagation, and, in the act of growing, evolve the products of the fermentation. "If the above liquids be left only in contact with air which has been passed through a red-hot platinum tube, and thus the living sporules destroyed; or if the air be simply filtered by passing through cotton wool, and the sporules prevented from coming into the liquid, it is found that these fermentable liquids may be preserved for any length of time without undergoing the slightest change."--Roscoe.] The effect, therefore, of fermentation is to change entirely the character of the substance upon which it acts; hence it is an error to assume that fermented liquors, as beer, wine, and cider, are safe drinks because the grains or fruits from which they are produced are healthful foods. YEAST is a ferment which causes alcoholic fermentation. It consists of microscopic plants, which increase by the formation of multitudes of tiny cells not more than 1/2400 of an inch in diameter. In the brewing of beer they grow in great abundance, making common brewer's yeast. Ferments or their spores float in the air ready to enter any fermentable liquid, and under favorable conditions they multiply with great activity and energy. The favorable conditions include the presence of oxygen or sugar; [Footnote: Yeast, like ordinary plants, buds and multiplies even in the absence of fermentable sugar, when it is furnished with free oxygen. This multiplication, however, is favored by the presence of sugar, which is a more appropriate element than non-fermentable hydrocarbon compounds. Yeast is also able to bud and multiply in the absence of free oxygen, but in this case a fermentable substance is indispensable.--SCHÜTZENBERGER'S _Fermentation_.] oxygen being, as we know, necessary for the development and the reproduction of all cell life (p. 107), and ferments having the power to resolve sugar, which penetrates by endosmose into the interior of the cell, into alcohol, carbonic acid, glycerine, succinic acid, and oxygen. BEER.--The barley used for making beer is first malted, _i. e._, sprouted, to turn a part of its starch into sugar. When this process has gone far enough, it is checked by heating the grain in a kiln until the germ is destroyed. The malt is then crushed, steeped, and fermented with hops and yeast. The sugar gradually disappears, alcohol is formed, and carbonic acid escapes into the air. The beer is then put into casks, where it undergoes a second, slower fermentation, and the carbonic acid gathers; when the liquor is drawn, this gas bubbles to the surface, giving to the beer its sparkling, foamy look. WINE is generally made from the juice of the grape. The juice, or _must_, as it is called, is placed in vats in the cellar, where the low temperature favors a slow fermentation. If all the sugar be converted into alcohol and carbonic-acid gas, a dry wine will remain; if the fermentation be checked, a sweet wine will result; and if the wine be bottled while the change is still going on, a brisk effervescing liquor like champagne, will be formed. All these are dangerous beverages because of the alcohol they contain. DISTILLATION.--Alcohol is so volatile that, by the application of heat, it can be driven off as a vapor from the fermented liquid in which it has been produced. Steam and various fragrant substances will accompany it, and, if they are collected and condensed in a cool receiver, a new and stronger liquor will be formed, having a distinctive odor. In this way whiskey is distilled from fermented corn, rye, barley, or potatoes; the alcohol of commerce is distilled from whiskey; brandy, from wine; rum, from fermented molasses; and gin, from fermented barley and rye, afterward distilled with juniper berries. VARIETIES AND PROPERTIES OF ALCOHOL.--There are several varieties of alcohol produced from distillation of various substances. Thus Methyl Alcohol is obtained from the decomposition of hard wood when exposed to intense heat with little or no oxygen present. It is a light, volatile liquid, which closely resembles ordinary alcohol in all its properties. It is used in the manufacture of aniline dyes, in making varnishes, and for burning in spirit lamps. Amyl Alcohol [Footnote: The odor of amylic alcohol is sweet, nauseous, and heavy. The sensation of its presence remains long. In taste it is burning and acrid, and it is itself practically insoluble in water. When it is diluted with common alcohol it dissolves freely in water, and gives a soft and rather unctuous flavor, I may call it a fruity flavor, something like that of ripe pears. Amyl alcohol, introduced as an adulterant, is an extremely dangerous addition to ordinary alcohol, in whatever form it is presented. From the quantities of it imported into this country, it is believed to be employed largely in the adulteration of wines and spirits.--RICHARDSON.] is the chief constituent of "fusel oil," found in whiskey distilled from potatoes. It is often present in common alcohol, giving a slightly unpleasant odor when it evaporates from the hand. Fusel oil is extremely poisonous and lasting in its effects, so that when contained in liquors it greatly increases their destructive and intoxicating properties. Ethyl Alcohol, which is that which we have described as obtained from fermentation of fruits and grains, is the ordinary alcohol of commerce. We have spoken of its volatility. This property permits it to pass into vapor at 56° Fahr. It boils at 173° Fahr. (Water boils at 212°.) Like Methyl Alcohol, it burns without smoke and with great heat, [Footnote: Pour a little alcohol into a saucer and apply an ignited match. The liquid will suddenly take fire, burning with intense heat, but feeble light. In this process, alcohol takes up oxygen from the air, forming carbonic-acid gas, and water.--Hold a red-hot coil of platinum wire in a goblet containing a few drops of alcohol, and a peculiar odor will be noticed. It denotes the formation of _aldehyde_--a substance produced in the slow oxidation of alcohol. Still further oxidized, the alcohol would be changed into _acetic acid_--the sour principle of vinegar.--Put the white of an egg--nearly pure albumen--into a cup, and pour upon it some alcohol, or even strong brandy; the fluid albumen will coagulate, becoming hard and solid. In this connection, it is well to remember that albumen is contained in our food, while the brain is largely an albuminous substance.] and is therefore of much value in the arts. Its great solvent power over fats and mixed oils renders it a useful agent in many industrial operations. It is also a powerful antiseptic, and no one who visits a museum of natural history will be likely to forget the rows of bottles within which float reptilian and batrachian specimens, preserved in alcohol. To alcohol, also, we are indebted for various anæsthetic agents, which, when not abused (p. 340), are of inestimable value. Thus, if certain proportions of alcohol and nitric acid be mixed together and heated, nitrite of amyl, so serviceable in relieving the agonizing spasms peculiar to that dread disease, angina pectoris, will be obtained. If, instead of nitric, we use sulphuric acid, we shall get ether; if chlorine be passed through alcohol, hydrate of chloral is the result; and, if chloride of lime and alcohol be treated together, the outcome is chloroform. One of the most striking properties of alcohol, and one which we shall hereafter consider in its disastrous effects upon the tissues of our body, is its affinity for water. [Footnote: Suppose, then, a certain measure of alcohol be taken into the stomach, it will be absorbed there, but, previous to absorption, it will have to undergo a proper degree of dilution with water; for there is this peculiarity respecting alcohol when it is separated by an animal membrane from a watery fluid like the blood, that it will not pass through the membrane until it has become charged, to a given point of dilution, with water. Alcohol is itself, in fact, so greedy for water that it will pick it up from watery textures, and deprive them of it until, by its saturation, its power of reception is exhausted, after which it will diffuse into the current of circulating fluid. To illustrate this fact of dilution I perform a simple experiment. Into a bladder is placed a mixture consisting of equal parts of alcohol and distilled water. Into the neck of the bladder a long glass tube is inserted and firmly tied. Then the bladder is immersed in a saline fluid representing an artificial serum of blood. The result is, that the alcohol in the bladder absorbs water from the surrounding saline solution, and thereby a column of fluid passes up into the glass tube. A second mixture of alcohol and water, in the proportion this time of one part of alcohol to two of water, is put into another bladder immersed in like manner in an artificial serum. In this instance a little fluid also passes from the outside into the bladder, so that there is a rise of water in the tube, but less than in the previous instance. A third mixture, consisting of one part of alcohol with three parts of water, is placed in another little bladder, and is also suspended in the artificial serum. In this case there is, for a time, a small rise of fluid in the tube connected with the bladder; but after a while, owing to the dilution which took place, a current from within outward sets in, and the tube becomes empty. Thus each bladder charged originally with the same quantity of fluid contains at last a different quantity. The first contains more than it did originally, the second only a little more, the third a little less. From the third, absorption takes place, and if I keep changing and replacing the outer fluid which surrounds the bladder with fresh serum, I can in time, owing to the double current of water into the bladder through its coats, and of water and alcohol out of the bladder into the serum, remove all the alcohol. In this way it is removed from the stomach into the circulating blood after it has been swallowed. When we dilute alcohol with water before drinking it, we quicken its absorption. If we do not dilute it sufficiently, it is diluted in the stomach by transudation of water in the stomach, until the required reduction for its absorption; the current then sets in toward the blood, and passes into the circulating canals by the veins.--RICHARDSON.] When strong alcohol is exposed to the air, it absorbs moisture and becomes diluted; at the same time, the spirit itself evaporates. The commercial or proof spirit is about one half water; the strongest holds five per cent; and to obtain absolute or waterless alcohol, requires careful distillation in connection with some substance, as lime, that has a still greater affinity for water, and so can despoil the alcohol. ALCOHOL IN ITS DESTRUCTIVE RELATION TO PLANT AND ANIMAL LIFE.--If we pour a little quantity of strong spirits upon a growing plant in our garden or conservatory, we shall soon see it shrivel and die. If we apply it to insects or small reptiles which we may have captured for specimens in our cabinet, the same potent poison will procure for them a speedy death. If we force one of our domestic animals to take habitual doses of it, the animal will not only strongly protest against the unnatural and nauseous potion, but it will gradually sicken and lose all power for usefulness. "If I wished," says a distinguished English physician, "by scientific experiment to spoil for work the most perfect specimen of a working animal, say a horse, without inflicting mechanical injury, I could choose no better agent for the purpose of the experiment than alcohol." [Footnote: "The effects produced by alcohol are common, so far as I can discover, to every animal. Alcohol is a universal intoxicant, and in the higher orders of animals is capable of inducing the most systematic phenomena of disease. But it is reserved for man himself to exhibit these phenomena in their purest form, and to present, through them, in the morbid conditions belonging to his age, a distinct pathology. Bad as this is, it might be worse; for if the evils of alcohol were made to extend equally to animals lower than man, we should soon have none that were tamable, none that were workable, and none that were eatable."] ALCOHOL IN WINE, BEER, AND CIDER IDENTICAL WITH ALCOHOL IN ARDENT SPIRITS.--In all liquors the active principle is alcohol. It comprises from six to eight per cent of ale and porter, seven to seventeen per cent of wine, and forty to fifty per cent of brandy and whiskey. All these may therefore be considered as alcohol more or less diluted with water and flavored with various aromatics. The taste of different liquors--as brandy, gin, beer, cider, etc.--may vary greatly, but they all produce certain physiological effects, due to their common ingredient--alcohol. "In whatever form it enters," says Dr. Richardson, "whether as spirit, wine, or ale, matters little when its specific influence is kept steadily in view. To say this man only drinks ale, that man only drinks wine, while a third drinks spirits, is merely to say, when the apology is unclothed, that all drink the same danger." In other words, the poisonous nature of alcohol, and the effects which result when it is taken into the stomach, are definite and immutable facts, which are not dependent upon any particular name or disguise under which the poison finds entrance. We shall learn, as we study the influence of alcohol upon the human system, that one of its most subtle characteristics is the progressive appetite for itself (p. 185) which it induces, an appetite which, in many cases, is formed long before its unhappy subject is aware of his danger. The intelligent pupil, who knows how to reason from cause to effect, needs hardly to be told, in view of this physical truth, of the peril that lies in the first draught of _any_ fermented liquor, even though it be so seemingly harmless as a glass of home-brewed beer or "slightly-beaded" cider. Few of us really understand our own inherent weakness or the hereditary proclivities (p. 186) that may be lurking in our blood, ready to master us when opportunity invites; but we may be tolerably certain that if we resolutely refuse to tamper with cider, beer, or wine, we shall not fall into temptation before rum, gin, or brandy. Since we know that in all fermented beverages there is present the same treacherous element, alcohol, we are truly wise only when we decline to measure arms in any way with an enemy so seductive in its advances, so insidious in its influence, and so terrible in its triumph. [Footnote: Aside from all considerations of physical, mental, and moral injury wrought by the use of alcoholic drinks, every young man may well take into account the damaging effect of such a dangerous habit upon his business prospects. Careful business men are becoming more and more unwilling to take into their employ any person addicted to liquor drinking. Within the past few years the officers of several railroads, having found that a considerable portion of their losses could be directly traced to the drinking habits of some one or more of their employés, have ordered the dismissal of all persons in their service who were known to use intoxicants, with the additional provision that persons thus discharged should never be reinstated. Many Eastern manufactories have adopted similar rules. All mercantile agencies now report the habits of business men in this respect, and some life insurance companies refuse to insure habitual drinkers, regarding such risks as "extra-hazardous."] Let us now consider the physiological effects of alcohol upon the organs immediately connected with the circulation of the blood. GENERAL EFFECT OF ALCOHOL UPON THE CIRCULATION.--During the experiment described on page 118, the influence of alcohol upon the blood may be beautifully tested. Place on the web of the frog's foot a drop of dilute spirit. The blood vessels immediately expand--an effect known as "_Vascular enlargement_." Channels before unseen open, and the blood disks fly along at a brisker rate. Next, touch the membrane with a drop of pure spirit. The blood channels quickly contract; the cells slacken their speed; and, finally, all motion ceases. The flesh shrivels up and dies. The circulation thus stopped is stopped forever. The part affected will in time slough off. Alcohol has killed it. The influence of alcohol upon the human system is very similar. When strong, as in spirits, it acts as an irritant, narcotic poison (p. 142, note). Diluted, as in fermented liquors, it dilates the blood vessels, quickens the circulation, hastens the heart throbs, and accelerates the respiration. THE EFFECT OF ALCOHOL UPON THE HEART.--What means this rapid flow of the blood? It shows that the heart is overworking. The nerves that lead to the minute capillaries and regulate the passage of the vital current through the extreme parts of the body, are paralyzed by this active narcotic. The tiny blood vessels at once expand. This "Vascular enlargement" removes the resistance to the passage of the blood, and a rapid beating of the heart results. [Footnote: Dr. B. W. Richardson's experiments tend to prove that this apparently stimulating action of alcohol upon the heart is due to the paralysis of the nerves that control the capillaries (Note, p. 208), which ordinarily check the flow of the blood (p. 117). The heart, like other muscles under the influence of alcohol, really loses power, and contracts less vigorously (p. 183). Dr. Palmer, of the University of Michigan, also claimed that alcohol, in fact, diminishes the strength of the heart. Prof. Martin, of Johns Hopkins University, from a series of carefully conducted experiments upon dogs, concluded that blood containing one fourth per cent of alcohol almost invariably diminishes within a minute the work done by the heart; blood containing one half per cent always diminishes it, and may reduce the amount pumped out by the left ventricle so that it is not sufficient to supply the coronary arteries. One hundred years ago, alcohol was always spoken of as a stimulant. Modern experiment and investigation challenged that definition, and it is now classified as a narcotic. There are, however, able physicians who maintain that, taken in small doses, and under certain physical conditions, it has the effect of a stimulant. All agree that, when taken in any amount, it tends to create an appetite for more.] Careful experiments show that two ounces of alcohol--an amount contained in the daily potations of a very moderate ale or whiskey drinker--increase the heart beats six thousand in twenty-four hours;--a degree of work represented by that of lifting up a weight of seven tons to a height of one foot. Reducing this sum to ounces and dividing, we find that the heart is driven to do extra work equivalent to lifting seven ounces one foot high one thousand four hundred and ninety-three times each hour! No wonder that the drinker feels a reaction, a physical languor, after the earliest effects of his indulgence have passed away. The heart flags, the brain and the muscles feel exhausted, and rest and sleep are imperatively demanded. During this time of excitement, the machinery of life has really been "running down." "It is hard work," says Richardson, "to fight against alcohol; harder than rowing, walking, wrestling, coal heaving, or the treadmill itself." All this is only the first effect of alcohol upon the heart. Long- continued use of this disturbing agent causes a "Degeneration of the muscular fiber," [Footnote: This "Degeneration" of the various tissues of the body, we shall find, as we proceed, is one of the most marked effects of alcoholized blood. The change consists in an excess of liquid, or, more commonly, in a deposit of fat. This fatty matter is not an increase of the organ, but it takes the place of a part of its fiber, thus weakening the structure, and reducing the power of the tissue to perform its function. Almost everywhere in the body we thus find cells--muscle cells, liver cells, nerve cells, as the case may be--changing one by one, under the influence of this potent disorganizer, into unhealthy fat cells. "Alcohol has been well termed," says the _London Lancet_, "the 'Genius of Degeneration.'" The cause of this degeneration can be easily explained. The increased activity of the circulation compels a correspondingly increased activity of the cell changes: but the essential condition of healthful change--the presence of additional oxygen--is wanting (see p. 143), and the operation is imperfectly performed.--BRODIE.] so that the heart loses its old power to drive the blood, and, after a time, fails to respond even to the spur of the excitant that has urged it to ruin. INFLUENCE UPON THE MEMBRANES.--The flush of the face and the bloodshot eye, that are such noticeable effects of even a small quantity of liquor, indicate the condition of all the internal organs. The delicate linings of the stomach, heart, brain, liver, and lungs are reddened, and every tiny vein is inflamed, like the blushing nose itself. If the use of liquor is habitual, this "Vascular enlargement," that at first slowly passed away after each indulgence, becomes permanent, and now the discolored, blotched skin reveals the state of the entire mucous membrane. We learned on page 55 what a peculiar office the membrane fills in nourishing the organs it enwraps. Anything that disturbs its delicate structure must mar its efficiency. Alcohol has a wonderful affinity for water. To satisfy this greed, it will absorb moisture from the tissues with which it comes in contact, as well as from their lubricating juices. The enlargement of the blood vessels and their permanent congestion must interfere with the filtering action of the membrane. In time, all the membranes become dry, thickened, and hardened; they then shrink upon the sensitive nerve, or stiffen the joint, or enfeeble the muscle. The function of these membranes being deranged, they will not furnish the organs with perfected material, and the clogged pores will no longer filter their natural fluids. Every organ in the body will feel this change. EFFECT UPON THE BLOOD. [Footnote: Alcohol acts upon the oxygen carrier, the coloring matter of the red corpuscles, causing it to settle in one part of the globule, or even to leave the corpuscle, and deposit itself in other elements of the blood. Thus the red corpuscle may become colorless, distorted, shrunken, and even entirely broken up--Dr. G. B. HARRIMAN.]-- From the stomach, alcohol passes directly into the circulation, and so, in a few minutes, is swept through the entire system. If it be present in sufficient amount and strength, its eager desire for water will lead it to absorb moisture from the red corpuscles, causing them to shrink, change their form, harden, and lose some of their ability to carry oxygen; it may even make them adhere in masses, and so hinder their passage through the tiny capillaries.--RICHARDSON. With most persons who indulge freely in alcoholic drinks, the blood is thin, the avidity of alcohol for water causing the burning thirst so familiar to all drinkers, and hence the use of enormous quantities of water, oftener of beer, which unnaturally dilutes the blood. The blood then easily flows from a wound, and renders an accident or surgical operation very dangerous. When the blood tends, as in other cases of an excessive use of spirits, to coagulate in the capillaries, [Footnote: The blood is rendered unduly thin, or is coagulated, according to the amount of alcohol that is carried into the circulatory system. "The spirit may fix the water with the fibrin, and thus destroy the power of coagulation; or it may extract the water so determinately as to produce coagulation. This explains why, in acute cases of poisoning by alcohol, the blood is sometimes found quite fluid, at other times firmly coagulated in the vessels."--B. W. RICHARDSON.] Reckless persons have sometimes drunk a large quantity of liquor for a wager, and, as the result of their folly, have died instantly. The whole of the blood in the heart having coagulated, the circulation was stopped, and death inevitably ensued.] there is a liability of an obstruction to the flow of the vital current through the heart, liver, lungs, etc., that may cause disease, and in the brain may lay the foundation of paralysis, or, in extreme cases, of apoplexy. Wherever the alcoholized blood goes through the body, it bathes the delicate cells with an irritating narcotic poison, instead of a bland, nutritious substance. EFFECT UPON THE LUNGS.--Here we can see how certainly the presence of alcohol interferes with the red corpuscles in their task of carrying oxygen. "Even so small a quantity as one part of alcohol to five hundred of the blood will materially check the absorption of oxygen in the lungs." The cells, unable to take up oxygen, retain their carbonic-acid gas, and so return from the lungs, carrying back, to poison the system, the refuse matter the body has sought to throw off. Thus the lungs no longer furnish properly oxygenized blood. The rapid stroke of the heart, already spoken of, is followed by a corresponding quickening of the respiration. The flush of the cheek is repeated in the reddened mucous membrane lining the lungs. When this "Vascular enlargement" becomes permanent, and the highly albuminous membrane of the air cells is hardened and thickened as well as congested, the Osmose of the gases to and fro through its pores can no longer be prompt and free as before. Even when the effect passes off in a few days after the occasional indulgence, there has been, during that time, a diminished supply of the life-giving oxygen furnished to the system; weakness follows, and, in the case of hard drinkers, there is a marked liability to epidemics. [Footnote: There is no doubt that alcohol alters and impairs tissues so that they are more prone to disease.--DR. G. K. SABINE. A volume of statistics could be filled with quotations like the following: "Mr. Huber, who saw in one town in Russia two thousand one hundred and sixty persons perish with the cholera in twenty days, said: 'It is a most remarkable circumstance that persons given to drink have been swept away like flies. In Tiflis, with twenty thousand inhabitants, every drunkard has fallen,--all are dead, not one remaining.'"] Physicians tell us, also, that there is a peculiar form of consumption known as Alcoholic Phthisis caused by long-continued and excessive use of liquor. It generally attacks those whose splendid physique has enabled them to "drink deep" with apparent impunity. This type of consumption appears late in life and is considered incurable. Severe cases of pneumonia are also generally fatal with inebriates. [Footnote: The Influence of Alcohol is continued in the chapter on Digestion.] PRACTICAL QUESTIONS. 1. Why does a dry, cold atmosphere favorably affect catarrh? 2. Why should we put on extra covering when we lie down to sleep? 3. Is it well to throw off our coats or shawls when we come in heated from a long walk? 4. Why are close-fitting collars or neckties injurious? 5. Which side of the heart is the more liable to inflammation? 6. What gives the toper his red nose? 7. Why does not the arm die when the surgeon ties the principal artery leading to it? 8. When a fowl is angry, why does its comb redden? 9. Why does a fat man endure cold better than a lean one? 10. Why does one become thin, during a long sickness? 11. What would you do if you should come home "wet to the skin"? 12. When the cold air strikes the face, why does it first blanch and then flush? 13. What must be the effect of tight lacing upon the circulation of the blood? 14. Do you know the position of the large arteries in the limbs, so that in case of accident you could stop the flow of blood? 15. When a person is said to be good-hearted, is it a physical truth? 16. Why does a hot footbath relieve the headache? 17. Why does the body of a drowned or strangled person turn blue? 18. What are the little "kernels" in the armpits? 19. When we are excessively warm, would the thermometer show any rise of temperature in the body? 20. What forces besides that of the heart aid in propelling the blood? 21. Why can the pulse be best felt in the wrist? 22. Why are starving people exceedingly sensitive to any jar? 23. Why will friction, an application of horse-radish leaves, or a blister relieve internal congestion? 24. Why are students very liable to cold feet? 25. Is the proverb that "blood is thicker than water" literally true? 26. What is the effect upon the circulation of "holding the breath"? 27. Which side of the heart is the stronger? 28. How is the heart itself nourished? [Footnote: The coronary artery, springing from the aorta just after its origin, carries blood to the muscular walls of the heart; the venous blood comes back through the coronary veins, and empties directly into the right auricle.] 29. Does any venous blood reach the heart without coming through the venæ cavæ? 30. What would you do, in the absence of a surgeon, in the case of a severe wound? (See p. 258.) 31. What would you do in the case of a fever? (See p. 263.) 32. What is the most injurious effect of alcohol upon the blood? 33. Are our bodies the same from day to day? 34. Show how life comes by death. 35. Is not the truth just stated as applicable to moral and intellectual, as to physical life? 36. What vein begins and ends with capillaries? _Ans_. The portal vein commences with capillaries in the digestive organs, and ends with the same kind of vessels in the liver. (See p. 166.) 37. By what process is alcohol always formed? Does it exist in nature? 38. What percentage of alcohol is contained in the different kinds of liquor? 39. Does cider possess the same intoxicating principle as brandy? 40. Describe the general properties of alcohol. 41. Show that alcohol is a narcotic poison. 42. If alcohol is not a stimulant, how does it cause the heart to overwork? 43. Why is the skin of a drunkard always red and blotched? 44. What danger is there in occasionally using alcoholic drinks? 45. What is meant by a fatty degeneration of the heart? 46. What keeps the blood in circulation between the beats of the heart? 47. What is the office of the capillaries? (See note, p. 373.) 48. Does alcohol interfere with this function? 49. How does alcohol interfere with the regular office of the membranes? 50. How does it check the process of oxidation? VI. DIGESTION AND FOOD. "A man puts some ashes in a hill of corn and thereby doubles its yield. Then he says, 'My ashes have I turned into corn.' Weak from his labor, he eats of his corn, and new life comes to him. Again, he says, 'I have changed my corn into a man.' This also he feels to be the truth. "It is the problem of the body, remember, that we are discussing. A man is more than the body; to confound the body and the man is worse than confounding the body and the clothing."--JOHN DARBY. ANALYSIS OF DIGESTION AND FOOD _ | 1. WHY WE NEED FOOD. | | 2. WHAT FOOD DOES. | _ _ | | 1. Nitrogenous. |_a. _The Sugars._ | 3. KINDS OF FOOD....| 2. Carbonaceous....|_b. _The Fats._ | |_3. Minerals | | 4. ONE KIND is INSUFFICIENT. | | 5. OBJECT OF DIGESTION. | _ | | --General Description | | _ | | 1. Mastication and | a. _The Saliva._ | | Insalvation......| b. _Process of | | |_ Swallowing._ | | _ | | | a. _The Stomach._ | | 2. Gastric | b. _The Gastric | | Digestion........| Juice._ | | |_c. _The Chyme_ | 6. PROCESSES OF | _ | DIGESTION........| | --Description | | | a. _The Bile_ | | 3. Intestional | b. _The Pancreatic | | Digestion........| Juice._ | | | c. _The Small | | |_ Intestine._ | | _ | | | a. _By the Veins._ | | 4. Absorption.......| b. _By the | |_ |_ Lacteals._ | | 7. COMPLEXITY OF THE PROCESS OF DIGESTION. | _ | | 1. Length of Time required. | | _ | | | a. _Beef._ | | | b. _Mutton._ | | | c. _Lamb._ | | 2. Value of dif- | d. _Pork._ | | ferent kinds | e. _Fish._ | | of food.........| f. _Milk._ | | | g. _Cheese._ | | |_h. _Eggs, etc._ | | _ | 8. HYGIENE..........| | a. _Coffee._ | | 3. The Stimulants...| b. _Tea._ | | |_C. _Chocolate._ | | 4. Cooking of Food. | | 5. Rapid Eating. | | 6. Quantity and Quality of Food. | | 7. When Food should be taken. | | 8. How Food should be taken. | |_9. Need of a Variety | | 9. THE WONDERS OF DIGESTION. | _ | | 1. Dyspepsia. | 10. DISEASES........|_2. The Mumps. | _ | | 1. Is Alcohol a Food? | | 2. Effect upon the Digestion. | | 3. Effect upon the Liver. | 11. ALCOHOLIC | 4. Effect upon the Kidneys. | DRINKS AND | 5. Does Alcohol impart heat? | NARCOTICS.......| 6. Does Alcohol impart strength? |_ | 7. The Effect upon the Waste of the Body. | 8. Alcohol creates a progressive appetite | for itself. |_9. Law of Heredity. DIGESTION AND FOOD. WHY WE NEED FOOD.--We have learned that our bodies are constantly giving off waste matter--the products of the fire, or oxidation, as the chemist terms the change going on within us (Note, p. 107). A man without food will starve to death in a few days, _i. e._, the oxygen will have consumed all the available flesh of his body. [Footnote: The stories current in the newspapers of persons who live for years without food, are, of course, untrue. The case of the Welsh Fasting Girl, which excited general interest throughout Great Britain, and was extensively copied in our own press, is in point. She had succeeded in deceiving not only the public, but, as some claim, her own parents. At last a strict watch was set by day and night, precluding the possibility of her receiving any food except at the hands of the committee, from whom she steadily refused it. In a few days she died from actual starvation. The youth of the girl, the apparent honesty of the parents, and the tragical sequel, make it one of the most remarkable cases of the kind on record.] To replace the daily outgo, we need about two and a quarter pounds of food, and three pints of drink. [Footnote: Every cell in the tissues is full of matter ready to set free at call its stored-up energy--derived from the meat, bread, and vegetables we have eaten. This energy will pass off quietly when the organs are in comparative rest, but violently when the muscles contract with force. When we send an order through a nerve to any part of the body, a series of tiny explosions run the entire length of the nerve, just as fire runs through a train of gunpowder. The muscle receives the stimulus, and, contracting, liberates its energy. The cells of nerve or muscle, whose contents have thus exploded, as it were, are useless, and must be carried off by the blood, just as ashes must be swept from the hearth, and new fuel be supplied to keep up a fire.] Including the eight hundred pounds of oxygen taken from the air, a man uses in a year about a ton and a half of material. [Footnote: The following is the daily ration of a United States soldier. It is said to be the most generous in the world: Bread or flour . . . . . . . . . 22 ounces. Fresh or salt beef (or pork or bacon, 12 oz.) . 20 " Potatoes (three times per week) . . . . . 16 " Rice . . . . . . . . . . . 1.6 " Coffee (or tea, 0.24 oz.) . . . . . . 1.6 " Sugar . . . . . . . . . . . 2.4 " Beans . . . . . . . . . . . 0.64 gill. Vinegar . . . . . . . . . . 0.32 " Salt . . . . . . . . . . . . 0.16 "] Yet during this entire time his weight may have been nearly uniform. [Footnote: If, however, he were kept on the scale pan of a sensitive balance, he would find that his weight is constantly changing, increasing with each meal, and then gradually decreasing.] Our bodies are but molds, in which a certain quantity of matter, checked for a time on its ceaseless round, receives a definite form. They may be likened, says Huxley, to an eddy in the river, which retains its shape for a while, yet every instant each particle of water is changing. WHAT FOOD DOES.--We make no force ourselves. We can only use that which nature provides for us. [Footnote: We draw from Nature at once our substance, and the force by which we operate upon her; being, so far, parts of her great system, immersed in it for a short time and to a small extent. Enfolding us, as it were, within her arms, Nature lends us her forces to expend; we receive them, and pass them on, giving them the impress of our will, and bending them to our designs, for a little while; and then--Yes; then it is all one. The great procession pauses not, nor flags a moment, for our fall. The powers which Nature lent to us she resumes to herself, or lends, it may be, to another; the use which we have made of them, or might have made and did not, is written in her book forever.--_Health and its Conditions_.] All our strength comes from the food we eat. Food is force--that is, it contains a latent power which it gives up when it is decomposed. [Footnote: This force is chemical affinity. It binds together the molecules which compose the food we eat. When oxygen tears the molecules to pieces and makes them up into smaller ones, the force is set free. As we shall learn in Physics, it can be turned, into heat, muscular motion, electricity, etc. The principle that the different kinds of force can be changed into one another without loss, is called the Conservation of Energy, and is one of the grandest discoveries of modern science.--_Popular Physics_, pages 35, 39, 278.] Oxygen is the magic key which unlocks for our use this hidden store. [Footnote: We have spoken of the mystery that envelops the process of the conversion of food force into muscular force (note, p. 107). All physiologists agree that muscular power has its source in the chemical decomposition of certain substances whereby their potential energy is released. Probably some of the food undergoes this chemical change before it passes out of the alimentary canal; possibly some is broken up by the oxygen while it is being swept along by the blood; but, probably by far the largest part is converted into the various tissues of the body, and finally becomes a waste product only after there takes place in the tissue itself that chemical disorganization that sets free its stored-up power.-- FOSTER'S _Physiology_.] Putting food into our bodies is like placing a tense spring within a watch; every motion of the body is only a new direction given to this food force, as every movement of the hand on the dial is but the manifestation of the power of the bent spring in the watch. We use the pent-up energies of meat, bread, and vegetables which are placed at our service, and transfer them to a higher theater of action. [Footnote: It is a grand thought that we can thus transform what is common and gross into the refined and spiritual; that out of waving wheat, wasting flesh, running water, and dead minerals, we can realize the glorious possibilities of human life.] KINDS OF FOOD NEEDED.--From what has been said it is clear that, in order to produce heat and force, we need something that will burn, _i. e._, with which oxygen can combine. Experiment has proved that to build up every organ, and keep the body in the best condition, we require three kinds of food. 1. _Nitrogenous Food_.--As nitrogen is a prominent constituent of the tissues of the body, food which contains it is therefore necessary to their growth and repair. [Footnote: Since this kind of food closely resembles albumen, it is sometimes called _Albuminous_. The term Proteid is also used.] The most common forms are whites of eggs--which are nearly pure albumen; casein--the chief constituent of cheese; lean meat; and gluten--the viscid substance which gives tenacity to dough. Bodies having a great deal of nitrogen readily oxidize. Hence the peculiar character of the quick-changing, force-exciting muscle. 2. _Carbonaceous Food_--_i. e._, food containing much carbon-- consists of two kinds, viz., the _sugars_, and the _fats_. (1) The _sugars_ contain hydrogen and oxygen in the proportion to form water, and about the same amount of carbon. They may, therefore, be considered as water, with carbon diffused through it. In digestion, starch and gum are changed to sugar, and so are ranked with this class. (2) The _fats_ are like the sugars in composition, but contain less oxygen, and not in the proportion to form water. They combine with more oxygen in burning, and so give off more heat. The non-nitrogenous elements of the food have, however, other uses than to develop heat. [Footnote: The heat they produce in burning may be turned into motion of the muscles, according to the principle of the Conservation of Energy (p. 153, note); while all the structures of the body in their oxidation develop heat.] Fat is essential to the assimilation of the food, while sugar and starch aid in digestion and may be converted into fat. [Footnote: In Turkey, the ladies of the harem are fed on honey and thick gruel, to make flesh, which is considered to enhance their beauty. The negroes on the sugar plantations of the South always grow fat during the sugar-making season.] Fat and carbonaceous material both enter into the composition of the various tissues, and when, by the breaking up of the contractile substance of the muscle, their latent energy is set free, they become the source of muscular force, as well as heat. While the tendency of the albuminous food is to excite chemical action, and hence the release of energy, the fats and carbonaceous food may be laid up in the body to serve as a storehouse of energy to supply future needs. 3. _Mineral Matters_.--Food should contain water, and certain common minerals, such as iron, [Footnote: While the body can build up a solid from liquid materials on the one hand, on the other it can pour iron through its veins and reduce the hardest textures to blood.--HINTON.] sulphur, magnesia, phosphorus, salt, and potash. About three pints of water are needed daily to dissolve the food and carry it through the circulation, to float off waste matter, to lubricate the tissues, and by evaporation to cool the system (see p. 317). It also enters largely into the composition of the body. A man weighing one hundred and fifty-four pounds contains one hundred pounds of water, about twelve gallons--enough, if rightly arranged, to drown him. [Footnote: It is said that Blumenbach had a perfect mummy of an adult Teneriffian, which with the viscera weighed only seven and a half pounds.] Iron goes to the blood disks; lime combines with phosphoric and carbonic acids to give solidity to the bones and teeth; phosphorus is essential to the activity of the brain. Salt is necessary to the secretion of some of the digestive fluids, and also to aid in working off from the system its waste products. These various minerals, except iron--sometimes given as a medicine, and salt--universally used as a condiment, [Footnote: Animals will travel long distances to obtain salt. Men will barter gold for it; indeed, among the Gallas and on the coast of Sierra Leone, brothers will sell their sisters, husbands their wives, and parents their children for salt. In the district of Accra, on the gold coast of Africa, a handful of salt is the most valuable thing upon earth after gold, and will purchase a slave. Mungo Park tells us that with the Mandingoes and Bambaras the use of salt is such a luxury that to say of a man "he flavors his food with salt," it is to imply that he is rich; and children will suck a piece of rock salt as if it were sugar. No stronger mark of respect or affection can be shown in Muscovy, than the sending of salt from the tables of the rich to their poorer friends. In the book of Leviticus it is expressly commanded as one of the ordinances of Moses, that every oblation of meat upon the altar shall be seasoned with salt, without lacking; and hence it is called the Salt of the Covenant of God. The Greeks and Romans also used salt in their sacrificial cakes; and it is still used in the services of the Latin church--the "_parva mica_" or pinch of salt, being in the ceremony of baptism, put into the child's mouth, while the priest says, "Receive the salt of wisdom, and may it be a propitiation to thee for eternal life." Everywhere and almost always, indeed, it has been regarded as emblematical of wisdom, wit, and immortality. To taste a man's salt, was to be bound by the rites of hospitality; and no oath was more solemn than that which was sworn upon bread and salt. To sprinkle the meat with salt was to drive away the devil, and to this day, nothing is more unlucky than to spill the salt.--LETHEBY, _On Food_.] are contained in small, but sufficient quantities in meat, bread, and vegetables. ONE KIND OF FOOD IS INSUFFICIENT.--A person fed on starch alone, would die. It would be a clear case of nitrogen starvation. On the other hand, as nitrogenous food contains carbon, the elements of water, and various mineral matters, life could be supported on that alone. But such a prodigious quantity of lean meat, for example, would be required to furnish the other elements, that not only would it be very expensive, but it is likely that after a time the labor of digestion would be too onerous, and the system would give up the task in despair. The need of a diet containing both nitrogenous and carbonaceous elements is shown in the fact that even in the tropical regions oil is relished as a dressing upon salad. Instinct everywhere suggests the blending. Butter is used with bread; rice is boiled with milk; cheese is eaten with macaroni, and beans are baked with pork. FIG. 45. [Illustration: _The Stomach and Intestines._ 1, _stomach;_ 2, _duodenum;_ 3, _small intestine;_ 4, _termination of the ileum;_ 5, _cœcum;_ 6, _vermiforn appendix;_ 7, _ascending colon;_ 8, _transverse colon;_ 9, _descending colon;_ 10, _sigmoid flexure of the colon;_ 11, _rectum;_ 12, _spleen--a gland whose action is not understood._--LEIDY'S _Anatomy._] THE OBJECT OF DIGESTION.--If our food were cast directly into the blood, it could not be used. For example, although the chemist can not see wherein the albumen of the egg differs from the albumen of the blood, yet if it be injected into the veins it is unavailable for the purposes required, and is thrown out again. In the course of digestion the food is modified in various ways whereby it is fitted for the use of the body, into which it is finally incorporated. We call this change of food into flesh _assimilation_, a name for a work done solely by the vital organs, and so mysterious in its nature that the wisest physiologist gets only glimpses here and there of its operations. THE GENERAL PLAN OF DIGESTION.--Nature has provided for this purpose an entire laboratory, furnished with a chemist's outfit of knives, mortars, baths, chemicals, filters, etc. The food is (1) chewed, mixed with the saliva in the mouth, and swallowed; (2) it is acted upon by the gastric juice in the stomach; (3) it is passed into the intestines, where it receives the bile, pancreatic juice, and other liquids which completely dissolve it; [Footnote: Digestion, says Berzelius, is a process of rinsing. The digestive apparatus secretes, and again absorbs with the food which it has dissolved, not less than three gallons of liquid per day.-- BARNARD, BIDDER, SCHMIDT, and others.] (4) the nourishing part is absorbed in the stomach and intestines, and thence thrown into the blood vessels, whence it is whirled through the body by the torrent of the circulation. These processes take place within the _alimentary canal_, a narrow tortuous tube which commences at the mouth, and is about thirty feet long. [Footnote: The digestive apparatus is lined with mucous membrane that possesses functions similar to those of the outer skin. It absorbs certain substances and rejects waste matter. On account of this close connection between the inner and the outer skin, it is not surprising to find that in the lowest animals digestion is performed by means of the external skin. The amœba, which is merely a gelatinous mass, when it takes its food, extemporizes a stomach for the occasion. It simply wraps itself around the morsel, and, like an animated apple dumpling with the apple for food and the crust for animal, goes on with the process until the operation is completed, when it unrolls itself again and lets the indigestible residue escape. The common hydra of our brooks can live when turned inside out, like a glove; either side serving for skin or stomach, as necessity requires.] FIG. 46. [Illustration: _The Parotid--one of the salivary glands._] I. MASTICATION AND INSALIVATION.--l. _The Saliva_.--The food while being cut and ground by the teeth is mixed with the saliva. This is a thin, colorless, frothy, slightly alkaline liquid, secreted [Footnote: By secretion is meant merely a separation or picking out from the blood.] by the mucous membrane lining the mouth, and by three pairs of salivary glands (parotid, submaxillary, and sublingual) opening into the mouth through ducts, or tubes. The amount varies, but on the average is about three pounds per day, and in health is always sufficient to keep the mouth moist. [Footnote: The presence and often the thought of food will "make one's mouth water." Fear checks the flow of saliva, and hence the East Indians sometimes attempt to detect theft by making those who are suspected chew rice. The person from whom it comes out driest is adjudged the thief.] It softens and dissolves the food, and thus enables us to get the flavor or taste of what we eat. It contains a peculiar organic principle called _ptyalin_, [Footnote: One part of ptyalin will convert eight thousand parts of starch into sugar.--MIALEE. The saliva has no chemical action on the fats or the albuminous bodies. Its frothiness enables it to carry oxygen into the stomach, and this is thought to be of service. The action of the ptyalin commences with great promptness, and sugar has been detected, it is said, within half a minute after the starch was placed in the mouth. The process, however, is not finished there, but continues after reaching the stomach.--VALENTIN. The saliva thus prepares a small portion of food for absorption at once, and so insures at the very beginning of the operation of digestion a supply of force-producing material for the immediate use of the system.] which, acting upon the starch of the food, changes it into glucose or grape sugar. 2. _The Process of Swallowing._--The food thus finely pulverized, softened, and so lubricated by the viscid saliva as to prevent friction as it passes over the delicate membranes, is conveyed by the tongue and cheek to the back of the mouth. The soft palate lifts to close the nasal opening; the epiglottis shuts down, and along this bridge the food is borne, without danger of falling into the windpipe or escaping into the nose. The muscular bands of the throat now seize it and take it beyond our control. The fibers of the œsophagus contract above, while they are lax below, and convey the food by a worm-like motion into the stomach. [Footnote: We can observe the peculiar motion of the œsophagus by watching a horse's neck when he is drinking.] II. GASTRIC DIGESTION.--1. _The Stomach_ is an irregular expansion of the digestive tube. Its shape has been compared to that of a bagpipe. It holds about three pints, though it is susceptible of some distension. It is composed of an inner, mucous membrane, which secretes the digestive fluids; an outer, smooth, well-lubricated serous one, which prevents friction, and between them a stout, muscular coat. The last consists of two principal layers of longitudinal and circular fibers. When these contract, they produce a peculiar churning motion, called the _peristaltic_ (_peri_, round; _stallein_, to arrange) movement, which thoroughly mixes the contents of the stomach. At the farther end, the muscular fibers contract and form a gateway, the _pylorus_ (a gate), as it is called, which carefully guards the exit, and allows no food to pass from the stomach until properly prepared. [Footnote: With a wise discretion, however, it opens for buttons, coins, etc., swallowed by accident; and when we overload the stomach, it seems to become weary of constantly denying egress, and, finally, giving up in despair, lets everything through.] FIG. 47. [Illustration: _Diagram of the Digestion of the Food. Notice how the food is submitted to the action of alkaline, acid, and then alkaline fluids. (See note, p._ 165.)] 2. _The Gastric Juice_.--The lining of the stomach is soft, velvety, and of a pinkish hue; but, as soon as food is admitted, the blood vessels fill, the surface becomes of a bright red, and soon there exudes from the gastric glands a thin, colorless fluid--the gastric juice. (See p. 319.) This is secreted to the amount of twelve pounds per day. [Footnote: The amount secreted by a healthy adult is variously estimated from five to thirty-seven pounds. As it is reabsorbed by the blood, there is no loss.] Its acidity is probably due to muriatic or lactic acid--the acid of sour milk. It contains a peculiar organic principle called _pepsin_ [Footnote: Pepsin is prepared and sold as an article of commerce. The best is said to be made from the stomachs of young, healthy pigs, which, just before being killed, are excited with savory food that they are not allowed to eat. One grain is sufficient to dissolve eight hundred grains of coagulated white of egg. A temperature of 130° renders pepsin inert.] (_peptein_, to digest), which acts as a ferment to produce changes in the food, without being itself modified. The flow of gastric juice is influenced by various circumstances. Cold water checks it for a time, and ice for a longer period. Anger, fatigue, and anxiety delay and even suspend the secretion. The gastric juice has no effect on the fats or the sugars of the food; its influence being mainly confined to the albuminous bodies, which it so changes that they become soluble in water. [Footnote: The question is often asked why the stomach itself is not digested by the gastric juice, since it belongs to the albuminous substances. Some have assigned as the probable reason that life protects that organ, and assert that living tissues can not be digested; but the fallacy of this has been clearly shown by experiments that have been made with living tissues in the course of scientific research. The latest opinion is that the blood which circulates so freely through the vessels of the lining of the stomach, being alkaline, protects the tissue against the acidity of the gastric juice.] The food, reduced by the action of the gastric juice to a grayish, soupy mass, called _chyme_ (kime), escapes through that jealously guarded door, the pylorus. Fig. 48. [Illustration: _A vertical Section of the Duodenum, highly magnified._ 1, _a fold-like villus;_ 2, epithelium, or cuticle;_ 3, _orifices of intestinal glands;_ 5, _orifice of duodenal glands;_ 4, 7, _more highly magnified sections of the cells of a duodenal gland._] III. INTESTINAL DIGESTION--The structure of the intestines is like that of the stomach. There is the same outer, smooth, serous membrane (peritoneum) to prevent friction, the lining of mucous membrane to secrete the digestive fluids, and the muscular coating to push the food forward. The intestines are divided into the _small_ and the _large_. The first part of the former opens out of the stomach, and is called the _du-o-de'-num_, as its length is equal to the breadth of twelve fingers. Here the chyme is acted upon by the _bile_, and the _pancreatic juice_. FIG. 49. [Illustration: _The Mucous Membrane of the Ilium, highly magnified._ 1, _cellular structure of the epithelium, or outer layer;_ 2, _a vein;_ 3, _fibrous layer;_ 4, _villi covered with epithelium;_ 5, _a villus in section, showing its lining of epithelium, with its blood vessels and lymphatics;_ 6, _a villus partially uncovered;_ 7, _a villus stripped of its epithelium;_ 8, _lymphatics or lacteals;_ 9, _orifices of the glands opening between the villi;_ 10, 11, 12, _glands;_ 13, _capillaries surrounding the orifices of the gland._] 1. _The Bile_ is secreted by the liver. This gland weighs about four pounds, and is the largest in the body. It is located on the right side, below the diaphragm. The bile is of a dark, golden color, and bitter taste. About three pounds are secreted per day. When not needed for digestion, it is stored in the gall cyst. [Footnote: A gall bladder can be obtained from a butcher, and the contents kept in a bottle for examination.] Its action on the food, though not fully understood, is necessary to life. [Footnote: The bile is produced, unlike all the other animal secretions, from venous blood; that is, the already contaminated blood of the portal vein. Its complete suppression produces symptoms of poisoning analogous to those which follow the stoppage of respiration, and the patient dies, usually in a comatose condition, at the end of ten or twelve days.--DALTON. The alkaline bile neutralizes the acid contents of the stomach as they flow into the duodenum, and thus prepares the way for the pancreatic juice. It has also a slight emulsifying power (note, p. 167).] 2. _The Pancreatic Juice_ is a secretion of the pancreas, or "sweetbread"--a gland nearly as large as the hand, lying behind the stomach. It is alkaline, and contains a ferment called _trypsin_. This juice has the power of changing starch to sugar. Its main work, however, is in breaking up the globules of fat into myriads of minute particles, that mix freely with water, and remain suspended in it like butter in new milk. The whole mass now assumes a milky look, whence it is termed _chyle_ (kile) and passes on to the small intestine. [Footnote: It is curious to observe that while the gastric juice is decidedly acid, the fluids with which the food next comes into contact are alkaline. It is thus submitted to the operation alternately of alkaline, acid, and again of alkaline secretions. In the herbivora there is also a second acid juice. The reason of these alternations is not known, but it can hardly be doubted that they serve to make the digestion of the food more perfect. And although the solvent power of the gastric juice is placed in abeyance when its acidity is neutralized by the alkaline fluids, yet it appears to be the case here, as in respect to the saliva, that effects are produced by the mixture of the various secretions which are poured together into the digestive tube, that would not result from either alone.--HINTON.] 3. _The Small Intestine_ is an intricately folded tube, about twenty feet long, and from an inch to an inch and one half in diameter. As the chyle passes through this tortuous channel, it receives along the entire route secretions which seem to combine the action of all the previous ones--starch, fat, and albumen being equally affected. IV. ABSORPTION is performed in two ways, by the _veins_, and the _lacteals_. (1.) The veins in the stomach [Footnote: The veins and the lacteals are separated from the food by a thin, moist membrane, through the pores of which the fluid food rapidly passes, in accordance with a beautiful law ("Popular Physics," p. 53) called the _Osmose_ of liquids. If two liquids of different densities are separated by an animal membrane, they will mix with considerable force. There is a similar law regulating the interchange of gases through a porous partition, in obedience to which the carbonic acid of the blood, and the oxygen of the lungs, are exchanged through the thin membrane of the air cells.] immediately begin to take up the water, salt, grape sugar, and other substances that need no special preparation. The starch and the albuminous bodies are also absorbed as they are properly digested, and this process continues along the whole length of the alimentary canal. In the small intestine, there is a multitude of tiny projections (_villi_) from the folds of the mucous membrane, more than seven thousand to the square inch, giving it a soft, velvety look. These little rootlets, reaching out into the milky fluid, drink into their minute blood vessels the nutritious part of every sort of food. (2.)The lacteals [Footnote: From _lac_, milk, because of the milky look given to their contents by the chyle.] (p. 126), a set of vessels starting in the villi side by side with the veins, absorb the principal part of the fat. They convey the chyle through the lymphatics and the thoracic duct (Fig. 43) to the veins, and so within the sweep of the circulation. The Portal Vein [Footnote: So named because it enters the liver by a sort of gateway.] carries to the liver the food absorbed by the veins of the stomach and the villi of the intestines. On the way, it is greatly modified by the action of the blood itself. In the cells of the liver, it undergoes as mysterious a process as that performed by the lymphatic glands, and is then cast into the circulation. [Footnote: In these cells, the sugar is changed into a kind of starch called _glycogen_. This is insoluble, and so is stored up in the liver, and even in the substance of the muscles, until it is needed by the body, when it is once more converted into soluble sugar and taken up by the circulation. The liver also changes the waste and surplus albuminous matter into bile, and into urea and uric acid--the forms in which nitrogenized waste is excreted by the kidneys.] The food, potent with force, is now buried in that river of life from which the body springs momentarily afresh. THE COMPLEXITY of the process of digestion, as compared with the simplicity of respiration and circulation, is very marked. The mechanical operation of mastication; the lubrication of the food by mucus; the provision for the security of the respiratory organs; the grasping by the muscles of the throat; the churning movement of the stomach; the guardianship of the pylorus; the timely introduction by safe and protected channels of the saliva, the gastric juice, the bile, the pancreatic juice, and the intestinal fluids, each with its special adaptation; the curious peristaltic motion of the intestines; the twofold absorption by the veins and the lacteals; the final transformation in the lymphatics, the portal vein, and the liver,--all these present a complexity of detail, the necessity of which can be explained only when we reflect upon the variety of the substances we use for food, and the importance of its thorough preparation before it is allowed to enter the blood. THE LENGTH OF TIME REQUIRED for digesting a full meal is from two to four hours. It varies with the kind of food, state of the system, perfection of mastication, etc. In the celebrated observations made upon Alexis St. Martin [Footnote: In 1822, Alexis St. Martin, a Canadian in the employ of the American Fur Company, was accidentally shot in the left side. Two years after, the wound was entirely healed, leaving, however, an opening about two and a half inches in circumference into the stomach. Through this the mucous membrane protruded, forming a kind of valve which prevented the discharge of food, but could be readily depressed by the finger, thus exposing the interior. For several years he was under the care of Dr. Beaumont, a skillful physician, who experimented upon him by giving various kinds of food, and watching their digestion through this opening. By means of these observations, and others performed on Katherine Kutt, a woman who had a similar aperture in the stomach, we have very important information as to the digestibility of different kinds of food.] by Dr. Beaumont, his stomach was found empty in two and a half hours after a meal of roast turkey, potatoes, and bread. Pigs' feet and boiled rice were disposed of in an hour. Fresh, sweet apples took one and a half hours; boiled milk, two hours; and unboiled, a quarter of an hour longer. In eggs, which occupied the same time, the case was reversed,--raw ones being digested sooner than cooked. Roast beef and mutton required three and three and a quarter hours respectively; veal, salt beef, and broiled chicken remained for four hours; and roast pork enjoyed the bad preeminence of needing five and a quarter hours. VALUE OF THE DIFFERENT KINDS OF FOOD.--_Beef_ and _Mutton_ possess the greatest nutritive value of any of the meats. _Lamb_ is less strengthening, but more delicate. Like the young of all animals, it should be thoroughly cooked, and at a high temperature, properly to develop its delicious flavor. _Pork_ has much carbon. It sometimes contains a parasite called trichina, which may be transferred to the human system, producing disease and often death. The only preventive is thorough cooking. _Fish_ is more watery than flesh, and many find it difficult of digestion. Like meat, it loses its mineral constituents and natural juices when salted, and is much less nourishing. Oysters are highly nutritious, but are more easily assimilated when raw than when cooked. _Milk_ is a model food, as it contains albumen, starch, fat, and mineral matter. No other single substance can sustain life for so long a time. _Cheese_ is very nourishing--one pound being equal in value to two of meat, but it is not adapted to a weak stomach. (See p. 322.) _Eggs_ are most easily digested when the white is barely coagulated and the yolk is unchanged. _Bread_ [Footnote: Very fresh bread, warm biscuit, etc., are condensed by mastication into a pasty mass that is not easily penetrated by the gastric juice, and hence they are not healthful. In Germany bread is not allowed to be sold at the baker's till it is twenty-four hours old--a wise provision for those who have not strength to resist temptation. This rule of eating may well be adopted by every one who cares more for his health than for a gratification of his appetite.] should be made of unbolted flour. The bran of wheat furnishes the mineral matter we need in our bones and teeth, gives the bulk so essential to the proper distension of the organs, and by its roughness gently stimulates them to action. _Corn_ is rich in fat. It contains, however, more indigestible matter than any other grain, except oats, and is less nutritious than wheat. [Footnote: Persons unaccustomed to the use of corn find it liable to produce derangement of the digestive organs. This was made fearfully apparent in the prisons of Andersonville during the late civil war. The vegetable food of the Federal prisoners had hitherto been chiefly wheat bread and potatoes--the corn bread so extensively used at the South being quite new to most of them as a constant article of diet. It soon became not only loathsome, but productive of serious diseases. On the other hand, it was the principal article in the rations of the Confederate soldiers, to whom habit made it a nutritious and wholesome form of food, as was shown by their endurance.--FLINT, _Physiology of Man_, Vol. II, page 41.] The _Potato_ is two thirds water,--the rest being mainly starch. _Ripe Fruits_, and those vegetables usually eaten raw, dilute the more concentrated food, and also supply the blood with acids, which are cooling in summer, and useful, perhaps, in assimilation. THE STIMULANTS.--_Coffee_ is about half nitrogen, and the rest fatty, saccharine, and mineral substances. It is, therefore, of much nutritive value, especially when taken with milk and sugar. Its peculiar stimulating property is due to a principle called _caffeine_. Its aroma is developed by browning, but destroyed by burning. No other substance so soon relieves the sense of fatigue. [Footnote: In the late civil war, the first desire of the soldiers upon halting after a wearisome march, was to make a cup of coffee. This was taken without milk, and often without sugar, yet was always welcome.] Taken in moderation, it clears the intellect, tranquilizes the nerves, and usually leaves no unpleasant reaction. It serves also as a kind of negative food, since it retards the process of waste. In some cases, however, it produces a rush of blood to the head, and should be at once discarded. At the close of a full meal it hinders digestion, and at night produces wakefulness. In youth, when the vital powers are strong, and the functions of nature prompt in rallying from fatigue, it is not needed, and may be injurious in stimulating a sensitive organization. _Tea_ possesses an active principle called _theine_. When used moderately, its effects are similar to those of coffee, except that it exerts an astringent action. It contains tannin, which, if the tea is strong, coagulates the albumen of the food--_tans_ it--and thus delays digestion. In excess, tea causes nervous tremor, disturbed sleep, palpitation of the heart, and indigestion. [Footnote: Tea and coffee should be made with, boiling water, but should not be boiled afterward. During the "steeping" process, so customary in this country, the volatile aroma is lost and a bitter principle extracted. In both England and China it is usual to infuse tea directly in the urn from which it is to be drawn. The tannin in tea is shown when a drop falls on a knife blade. The black spot is a tannate of iron--a compound of the acid in the tea and the metal.] (See p. 322.) _Chocolate_ contains much fat, and also nitrogenous matter resembling albumen. Its active principle, _theobromine_, [Footnote: It is said that Linnæus, the great botanist, was so fond of chocolate that he named the cocoa tree "Theobroma," the food of the gods.] has some of the properties of caffeine and theine. THE COOKING OF FOOD breaks the little cells, and softens the fibers of which it is composed. In broiling or roasting meat, it should be exposed to a strong heat at once, in order to coagulate the albumen upon the outside, and thus prevent the escape of the nutritious juices. The cooking may then be finished at a lower temperature. The same principle applies to boiling meat. In making soups, on the contrary, the heat should be applied slowly, and should reach the boiling point for only a few moments at the close. This prevents the coagulation of the albumen. Frying is an unhealthful mode of cooking food, as thereby the fat becomes partially disorganized. RAPID EATING produces many evil results. 1. There is not enough saliva mixed with the food; 2. The coarse pieces resist the action of the digestive fluids; 3. The food is washed down with drinks that dilute the gastric juice, and hinder its work; 4. We do not appreciate the quantity we eat until the stomach is overloaded; 5. Failing to get the taste of our food, we think it insipid, and hence use condiments that overstimulate the digestive organs. In these various ways the appetite becomes depraved, the stomach vexed, the system overworked, and the foundation of dyspepsia is laid. [Footnote: When one is compelled to eat in a hurry, as at a railway station, he would do well to confine himself principally to meat; and to dilute this concentrated food with fruit, crackers, etc., taken afterward more leisurely.] (See p. 324.) THE QUANTITY AND QUALITY OF FOOD required vary with the age and habits of each individual. The diet of a child [Footnote: In youth, repair exceeds waste; hence the body grows rapidly, and the form is plump. In middle life, repair and waste equal each other, and growth ceases. In old age, waste exceeds repair; hence the powers are enfeebled and the skin lies in wrinkles on the shrunken form.] should be largely vegetable, and more abundant than that of an aged person. A sedentary occupation necessitates less food than an outdoor life. One accustomed to manual labor, on entering school, should practice self-denial until his system becomes fitted to the new order of things. He should not, however, fall into the opposite error. We read of great men who have lived on bread and water, and the conscientious student sometimes thinks that, to be great, he, too, must starve himself. [Footnote: As Dr. Holland well remarks, the dispensation of sawdust has passed away. If we desire a horse to win the race, we must give him plenty of oats.] On the contrary, many of the greatest workers are the greatest eaters. A powerful engine needs a corresponding furnace. Only, we should be careful not to use more fuel than is needed to run the machine. (See p. 325.) The season should modify our diet. In winter, we need highly carbonaceous food, plenty of meat, fat, etc.; but in summer we should temper the heat in our corporeal stoves with fruits and vegetables. The climate also has its necessities. The inhabitants of the frigid north have an almost insatiable longing for fat. [Footnote: Dr. Hayes, the arctic explorer, says, that the daily ration of the Esquimaux was from twelve to fifteen pounds of meat, one third being fat. On one occasion, he saw a man eat ten pounds of walrus flesh and blubber at a single meal. The low temperature had a remarkable effect on the members of his own party, and some of them were in the habit of drinking the contents of the oil kettle with evident relish. Other travelers narrate the most incredible stories of the voracity of the inhabitants of arctic regions. Saritcheff, a Russian admiral, tells of a man who in his presence ate, at a meal, a mess of twenty-eight pounds of boiled rice and butter, although he had already partaken of his breakfast. Captain Cochrane further adds, in narrating this statement, that he has himself seen three of the savages consume a reindeer at a sitting.] Thus, in 1812, when the Allies entered Paris, the Cossacks drank all the oil from the lamps, and left the streets in darkness. In tropical regions, a low, unstimulating diet of fruits forms the chief dependence. [Footnote: A natural appetite for a particular kind of food is an expression not only of desire, but of fitness. Thus the craving of childhood for sugar indicates a need of the system. It is questionable how far it is proper to force or persuade one to eat that which he disrelishes, or his stomach loathes. Life within is linked with life without. Each organ requires its peculiar nutriment, and there is often a peculiar influence demanded of which we can have no notice except by natural instinct. Yet, as we are creatures of habit and impulse, we need common sense and good judgment to correct the too often wayward promptings of an artificial craving.] WHEN FOOD SHOULD BE TAKEN.--On taking food, the blood sets at once to the alimentary canal, and the energies are fixed upon the proper performance of this work. We should not, therefore, undertake hard study, labor, or exercise directly after a hearty meal. We should give the stomach at least half an hour. He who toils with brain or muscle, and thus centers the blood in any particular organ, before eating should allow time for the circulation to become equalized. There should be an interval of four to five hours between our regular meals, and there should be no lunching between times. With young children, where the vital processes are more rapid, less time may intervene. As a general rule, nothing should be eaten within two or three hours of retiring. (See p 336.) HOW FOOD SHOULD BE TAKEN.--A good laugh is the best of sauces. The mealtime should be the happiest hour of the day. Care and grief are the bitter foes of digestion. A cheerful face and a light heart are friends to long life, and nowhere do they serve us better than at the table. God designed that we should enjoy eating, and that, having stopped before satiety was reached, we should have the satisfaction always attendant on a good work well done. NEED OF VARIETY.--Careful investigations have shown that any one kind of food, however nutritious in itself, fails after a time to preserve the highest working power of the body. Our appetite palls when we confine our diet to a regular routine. Nature demands variety, and she has furnished the means of gratifying it. [Footnote: She opens her hand, and pours forth to man the treasures of every land and every sea, because she would give to him a wide and vigorous life, participant of all variety. For him the cornfields wave their golden grain--wheat, rye, oats, maize, or rice, each different, but alike sufficing. Freely for him the palm, the date, the banana, the breadfruit tree, the pine, spread out a harvest on the air; and pleasant apple, plum, or peach solicit his ready hand. Beneath his foot lie stored the starch of the potato, the gluten of the turnip, the sugar of the beet; while all the intermediate space is rich with juicy herbs. Nature bids him eat and be merry; adding to his feast the solid flesh of bird, and beast, and fish, prepared as victims for the sacrifice: firm muscle to make strong the arm of toil, in the industrious temperate zone; and massive ribs of fat to kindle inward fires for the sad dwellers under arctic skies.--_Health and its Conditions_.--HINTON.] THE WONDERS OF DIGESTION.--We can understand much of the process of digestion. We can look into the stomach and trace its various steps. Indeed, the chemist can reproduce in his laboratory many of the operations; "a step further," as Fontenelle has said, "and he would surprise nature in the very act." Just here, when he seems so successful, he is compelled to pause. At the threshold of life the wisest physiologist reverently admires, wonders, and worships. How strange is this transformation of food to flesh! We make a meal of meat, vegetables, and drink. Ground by the teeth, mixed by the stomach, dissolved by the digestive fluids, it is swept through the body. Each organ, as it passes, snatches its particular food. Within the cells of the tissues [Footnote: As the body is composed of individual organs, and each organ of separate tissues, so each tissue is made up of minute cells. Each cell is a little world by itself, too small to be seen by the naked eye, but open to the microscope. It has its own form and constitution as much as a special organ in the body. It absorbs from the blood such food as suits its purposes. Moreover, the number of cells in an organ is as constant as the number of organs. As the organs expand with the growth of the body, so the cells of each tissue enlarge, but shrink again with age and the decline of life. Life begins and ends in a cell.--See _Appletons' Cyclopedia_, Art. "Absorption."] it is transformed into the soft, sensitive brain, or the hard, callous bone; into briny tears, or bland saliva, or acrid perspiration; bile for digestion, oil for the hair, nails for the fingers, and flesh for the cheek. Within us is an Almighty Architect, who superintends a thousand builders, which make in a way past all human comprehension, here a fiber of a muscle, there a filament of a nerve; here constructing a bone, there uniting a tendon,--fashioning each with scrupulous care and unerring nicety. [Footnote: See COOKE'S _Religion and Chemistry_, page 236.] So, without sound of builder or stroke of hammer, goes up, day by day, the body--the glorious temple of the soul. DISEASES ETC.--1. _Dyspepsia_, or indigestion of food, is generally caused by an overtaxing of the digestive organs. Too much food is used, and the entire system is burdened by the excess. Meals are taken at irregular hours, when the fluids are not ready. A hearty supper is eaten when the body, wearied with the day's labor, demands rest. The appetite craves no food when the digestion is enfeebled, but stimulants and condiments excite it, and the unwilling organs are oppressed by that which they can not properly manage. Strong tea, alcoholic drinks, and tobacco derange the alimentary function. Too great variety of dishes, rich food, tempting flavors,--all lead to an overloading of the stomach. This patient, long-suffering member at last wears out. Pain, discomfort, diseases of the digestive organs, and insufficient nutrition are the penalties of violated laws. (See p. 328.) 2. _The Mumps_ are an inflammation of the parotid and submaxillary glands (see p. 159). The disease is generally epidemic, and is believed to be contagious; the patient should therefore be carefully secluded for the sake of others as well as himself. The swelling may be allowed to take its course. Relief from pain is often experienced by applying flannels wrung out of hot water. Great care should be used not to check the inflammation, and, on first going out after recovery, not to take cold. ALCOHOLIC DRINKS AND NARCOTICS. 1. ALCOHOL (Continued from p. 147). RELATION OF ALCOHOL TO THE DIGESTIVE ORGANS.--_Is Alcohol a Food?_ To answer this question, let us make a comparison. If you receive into your stomach a piece of bread or beef, Nature welcomes its presence. The juices of the system at once take hold of it, dissolve it, and transform it for the uses of the body. A million tiny fingers (lacteals and veins) reach out to grasp it, work it over, and carry it into the circulation. The blood bears it onward wherever it is needed to mend or to build "The house you live in." Soon, it is no longer bread or beef; it is flesh on your arm; its chemical energy is imparted to you, and it becomes your strength. If, on the other hand, you take into your stomach a little alcohol, it receives no such welcome. Nature treats it as a poison, and seeks to rid herself of the intruder as soon as possible. [Footnote: Food is digested, alcohol is not. Food warms the blood, directly or indirectly; alcohol lowers the temperature. Food nourishes the body, in the sense of assimilating itself to the tissues; alcohol does not. Food makes blood; alcohol never does anything more innocent than mixing with it. Food feeds the blood cells; alcohol destroys them. Food excites, in health, to normal action only; alcohol tends to inflammation and disease. Food gives force to the body; alcohol excites reaction and wastes force, in the first place, and in the second, as a true narcotic, represses vital action and corresponding nutrition.--If alcohol does not act like food, neither does it behave like water. Water is the subtle but innocent vehicle of circulation, which dissolves the solid food, holds in play the chemical and vital reactions of the tissues, conveys the nutritive solutions from cell to cell, from tube to tube, and carries off and expels the effete matter. Water neither irritates tissue, wastes force, nor suppresses vital action: whereas alcohol does all three. Alcohol hardens solid tissue, thickens the blood, narcotizes the nerves, and in every conceivable direction antagonizes the operation and function of water--LEES.] The juices of the system will flow from every pore to dilute and weaken it, and to prevent its shriveling up the delicate membranes with which it comes in contact. The veins will take it up and bear it rapidly through the system. Every organ of elimination, all the scavengers of the body-- the lungs, the kidneys, the perspiration glands, at once set to work to throw off the enemy. So surely is this the case, that the breath of a person who has drunk only a single glass of the lightest beer will betray the fact. The alcohol thus eliminated is entirely unchanged. Nature apparently makes no effort to appropriate it. [Footnote: It was formerly a question considerably discussed, whether alcohol exists in the brain, or in the fluid found in the ventricles, in intoxicated persons. This was settled by Percy, who found alcohol in the brain and liver of dogs poisoned with alcohol, and of men who had died after excessive drinking. In these experiments, the presence of alcohol was determined by distillation, and the distilled substance burned with a blue flame, and dissolved camphor.-- FLINT'S _Physiology of Man_.] It courses everywhere through the circulation, and into the great organs, with all its properties unmodified. Alcohol, then, is not, like bread or beef, taken hold of, broken up by the mysterious process of digestion, and used by the body. [Footnote: Because of the difficulties of such an experiment, we have not yet been able to account satisfactorily by the excretions for all the alcohol taken into the stomach. This remains as yet one of the unsolved problems of physiological chemistry. To collect the whole of the insensible perspiration, for example, is well-nigh impossible. It was supposed at one time that a part of the alcohol is oxidized--_i. e._, burned, in the system. But such a process would impart heat, and it is now proved that alcohol cools, instead of warms, the blood. Moreover, the closest analysis fails to detect in the circulation any trace of the products of alcoholic combustion, such as aldehyde and acetic acid. "The fact," says Flint, "that alcohol is always eliminated, even when drunk in minute quantity, and that its elimination continues for a considerable time, gradually diminishing, renders it probable that all that is taken into the body is removed."] "It can not therefore be regarded as an aliment," or food.-- FLINT. "Beer, wine, and spirits," says Liebig, "contain no element capable of entering into the composition of the blood or the muscular fiber." [Footnote: The small amount of nutritive substance, chiefly sugar derived from the grain or fruit used in the manufacture of beer or wine, can not, of course, be compared with that contained in bread or beef at the same cost. Liebig says, in his Letters on Chemistry, "We can prove, with mathematical certainty, that as much flour as can lie on the point of a table knife is more nutritious than eight quarts of the best Bavarian beer."] "That alcohol is incapable of forming any part of the body," remarks Cameron, "is admitted by all physiologists. It can not be converted into brain, nerve, muscle, or blood." EFFECT UPON THE DIGESTION. [Footnote: The medical value of alcohol in its relations to digestion is not discussed in this book. The experiments of Dr. Henry Munroe, of Hull, published in the London _Medical Journal_, are here summarized as showing that the tendency to retard digestion is common to all forms of alcoholic drinks. _______________________________________________________________________ Finely Minced | | | | Beef | 2d Hour | 4th Hour | 6th Hour | _______________________________________________________________________ I. | | Digesting | | Gastric Juice | Beef | and | Beef much | and _water_. | opaque. | separating. | loosened. | _______________________________________________________________________ | | Slightly | Slight | II. | No alteration | opaque, but | coating on | Gastric Juice | perceptible. | beef | beef. | with _alcohol_. | | unchanged. | | _______________________________________________________________________ III. | | Cloudy, | beef | Gastric Juice | No change. | with fur | partly | and _pale ale_. | | on beef. | loosened. | _______________________________________________________________________ ______________________________________________________ Finely Minced | | | Beef | 8th Hour | 10th Hour | ______________________________________________________ I. | | | Gastric Juice | Beef | Broken up | and _water_. | opaque. | into shreds. | ______________________________________________________ | | Solid on | II. | No visible | cooling | Gastric Juice | change. | _Pepsin_ | with _alcohol_. | | precipitated. | ______________________________________________________ III. | | No digestion | Gastric Juice | No further | _Pepsin_ | and _pale ale_. | change. | precipitated. | ______________________________________________________] --Experiments tend to prove that alcohol coagulates and precipitates the pepsin from the gastric juice, and so puts a stop to its great work in the process of digestion. The greed of alcohol for water causes it to imbibe moisture from the tissues and juices, and to inflame the delicate mucous membrane. It shows the power of Nature to adapt herself to circumstances, that the soft, velvety lining of the throat and stomach should come at length to endure the presence of a fiery liquid which, undiluted, would soon shrivel and destroy it. In self-defense, the juices pour in to weaken the alcohol, and it is soon hurried into the circulation. Before this can be done, "it must absorb about three times its bulk of water"; hence, very strong liquor may be retained in the stomach long enough to interfere seriously with the digestion, and to injure the lining coat. Habitual use of alcohol permanently dilates the blood vessels; thickens and hardens the membranes; in some cases, ulcerates the surface; and, finally, "so weakens the assimilation that the proper supply of food can not be appropriated." --FLINT. [Footnote: The case of St. Martin (p. 168) gave an excellent opportunity to watch the action of alcohol upon the stomach. Dr. Beaumont summarized his experiments thus: "The free, ordinary use of any intoxicating liquor, when continued for some days, invariably produced inflammation, ulcerous patches, and, finally, a discharge of morbid matter tinged with blood." Yet St. Martin never complained of pain in his stomach, the narcotic influence of the alcohol preventing the signal of danger that Nature ordinarily gives.] EFFECT UPON THE LIVER.--Alcohol is carried by the portal vein directly to the liver. This organ, after the brain, holds the largest share. The influence of the poison is here easily traced. "The color of the bile is soon changed from yellow to green, and even to black;" the connective tissue between the lobules becomes inflamed; and, in the case of a confirmed drunkard, hardened and shrunk, the surface often assuming a nodulated appearance known as the "hobnailed liver." Morbid matter is sometimes deposited, causing what is called "Fatty degeneration," so that the liver is increased to twice or thrice its natural size. EFFECT UPON THE KIDNEYS.--The kidneys, like the liver, are liable in time to undergo, through the influence of alcohol, a "Fatty degeneration," in which the cells become filled with particles of fat; [Footnote: Disabled by the fatty deposits, the kidneys are unable to separate the waste matter coming to them for elimination from the system. The poisonous material is poured back into the circulation, and often delirium ensues.--HUBBARD. Richardson states that his experience "is to the effect that seven out of every eight instances of kidney disease are attributable to alcohol."] the vessels lose their contractility; and, worst of all, the membranes may be so modified as to allow the albuminous part of the blood to filter through them, and so to rob the body of one of its most valuable constituents. [Footnote: This deterioration of structure frequently gives rise to what is known as "Bright's Disease."--RICHARDSON.] DOES ALCOHOL IMPART HEAT?--During the first flush after drinking wine, for example, a sense of warmth is felt. This is due to the tides of warm blood that are being sent to the surface of the body, owing to the vascular enlargement and to the rapid pumping of the heart. There is, however, no fresh heat developed. On the contrary, the bringing the blood to the surface causes it to cool faster, reaction sets in, a chilliness is experienced as one becomes sober, and a delicate thermometer placed under the tongue of the inebriate may show a fall of even two degrees below the standard temperature of the body. Several hours are required to restore the usual heat. As early as 1850, Dr. N. S. Davis, of Chicago, ex-President of the American Medical Association, instituted an extensive series of experiments to determine the effect of the different articles of food and drinks on the temperature of the system. He conclusively proved that, during the digestion of all kinds of food, the temperature of the body is increased, but when alcohol is taken, either in the form of fermented or distilled beverages, the temperature begins to fall within a half hour, and continues to decrease for two or three hours, and that the reduction of temperature, in extent as well as in duration, is in exact proportion to the amount of alcohol taken. It naturally follows that, contrary to the accepted opinion, liquor does not fortify against cold. The experience of travelers at the North coincides with that of Dr. Hayes, the Arctic explorer, who says: "While fat is absolutely essential to the inhabitants and travelers in arctic countries, alcohol is, in almost any shape, not only completely useless, but positively injurious. I have known strong, able-bodied men to become utterly incapable of resisting cold in consequence of the long-continued use of alcoholic drink." DOES ALCOHOL IMPART STRENGTH?--Experience shows that alcohol weakens the power of undergoing severe bodily exertion. [Footnote: Dr. McRae, in speaking of Arctic exploration, at the meeting of the American Association for the Advancement of Science, held at Montreal in 1856, said: "The moment that a man had swallowed a drink of spirits, it was certain that his day's work was nearly at an end. It was absolutely necessary that the rule of total abstinence be rigidly enforced, if we would accomplish our day's task. The use of liquor as a beverage when we had work on hand, in that terrific cold, was out of the question."] Men who are in training for running, rowing, and other contests where great strength is required, deny themselves all liquors, even when they are ordinarily accustomed to their use. Dr. Richardson made some interesting experiments to show the influence of alcohol upon muscular contraction. He carefully weighted the hind leg of a frog, and, by means of electricity, stimulating the muscle to its utmost power of contraction, he found out how much the frog could lift. Then administering alcohol, he discovered that the response of the muscle to the electrical current became feebler and feebler, as the narcotic began to take effect, until, at last, the animal could raise less than half the amount it lifted by the natural contraction when uninfluenced by alcohol. EFFECT UPON THE WASTE OF THE BODY.--The tendency of alcohol is to cause a formation of an unstable substance resembling fat, [Footnote: The molecular deposits equalizing the waste of the system do not go on regularly under the influence of alcohol; the tissues are not kept up to their standard; and, in time, their composition is changed by a deposit of an amorphous matter resembling fat. This is an unstable substance, and the functions of animal life all retrograde.--HUBBARD, _The Opium Habit and Alcoholism_.] and so the use of liquor for even a short time will increase the weight. But a more marked influence is to check the ordinary waste of the system, so that "the amount of carbonic acid exhaled from the lungs may be reduced as much as thirty to fifty per cent."--HINTON. The life process is one of incessant change. Its rapidity is essential to vigor and strength. When the functions are in full play, each organ is being constantly torn down, and as constantly rebuilt with the materials furnished from our food. Anything that checks this oxidation of the tissues, or hinders the deposition of new matter, disturbs the vital functions. Both these results are the inevitable effects of alcohol; for, since the blood contains less oxygen and more carbonic acid, and the power of assimilating the food is decreased, it follows that every process of waste and repair must be correspondingly weakened. The person using liquor consequently needs less bread and beef, and so alcohol seems to him a food--a radical error, as we have shown. ALCOHOL CREATES A PROGRESSIVE APPETITE FOR ITSELF.--When liquor is taken, even in the most moderate quantity, it soon becomes necessary, and then arises a craving demand for an increased amount to produce the original effect. No food creates this constantly augmenting want. A cup of milk drank at dinner does not lead one to go on, day by day, drinking more and more milk, until to get milk becomes the one great longing of the whole being. Yet this is the almost universal effect of alcohol. Hunger is satisfied by any nutritious food: the dram-drinker's thirst demands alcohol. The common experience of mankind teaches us the imminent peril that attends the formation of this progressive poison habit. A single glass taken as a tonic may lead to the drunkard's grave. Worse than this, the alcoholic craving may be transmitted from father to son, and young persons often find themselves cursed with a terrible disease known as alcoholism--a keen, morbid appetite for liquor that demands gratification at any cost--stamped upon their very being through the reckless indulgence of this habit on the part of some one of their ancestors. [Footnote: The American Medical Association, at their meeting in St. Paul, Minnesota (1883), restated in a series of resolutions their conviction, that "alcohol should be classed with other powerful drugs; that when prescribed medically, it should be done with conscientious caution and a sense of great responsibility; that used as a beverage it is productive of a large amount of physical and mental disease; that it _entails diseased and enfeebled constitutions upon offspring_, and that it is the cause of a large percentage of the crime and pauperism of our large cities and country."] THE LAW OF HEREDITY is, in this connection, well worth consideration. "The world is beginning to perceive," says Francis Galton, "that the life of each individual is, in some real sense, a continuation of the lives of his ancestors." "Each of us is the footing up of a double column of figures that goes back to the first pair." "We are omnibuses," remarks Holmes, "in which all our ancestors ride." We inherit from our parents our features, our physical vigor, our mental faculties, and even much of our moral character. Often, when one generation is skipped, the qualities will reappear in the following one. The virtues, as well as the vices, of our forefathers, have added to, or subtracted from, the strength of our brain and muscle. The evil tendencies of our natures, which it is the struggle of our lives to resist, constitute a part of our heirlooms from the past. Our descendants, in turn, will have reason to bless us only if we hand down to them a pure healthy physical, mental, and moral being. "There is a marked tendency in nature to transmit all diseased conditions. Thus, the children of consumptive parents are apt to be consumptives. But of all agents, alcohol is the most potent in establishing a heredity that exhibits itself in the destruction of mind and body. [Footnote: Nearly all the diseases springing from indulgence in distilled and fermented liquors are liable to become hereditary, and to descend to at least three or four generations, unless starved out by uncompromising abstinence. But the distressing aspect of the heredity of alcohol is the transmitted drink- crave. This is no dream of an enthusiast, but the result of a natural law. Men and women upon whom this dread inheritance has been forced are everywhere around us, bravely struggling to lead a sober life.--DR. NORMAN KERR.] Its malign influence was observed by the ancients long before the production of whiskey or brandy, or other distilled liquors, and when fermented liquors or wines only were known. Aristotle says, 'Drunken women have children like unto themselves,' and Plutarch remarks, 'One drunkard is the father of another.' The drunkard by inheritance is a more helpless slave than his progenitor, and his children are more helpless still, unless on the mother's side there is an untainted blood. For there is not only a propensity transmitted, but an actual disease of the nervous system."--DR. WILLARD PARKER. [Footnote: The subject of alcohol is continued in the chapter on the Nervous System.] PRACTICAL QUESTIONS. 1. How do clothing and shelter economize food? 2. Is it well to take a long walk before breakfast? 3. Why is warm food easier to digest than cold? 4. Why is salt beef less nutritious than fresh? [Footnote: The French Academicians found that flesh soaked in water so as to deprive it of its mineral matter and juices, lost its nutritive value, and that animals fed on it soon died. Indeed, for all purposes of nutrition, Liebig said it was no better than stones, and the utmost torments of hunger were hardly sufficient to induce them to continue the diet. There was plenty of nutritive food, but there was no medium for its solution and absorption, and hence it was useless.] 5. What should be the food of a man recovering from a fever? 6. Is a cup of black coffee a healthful close to a hearty dinner? 7. Should iced water be used at a meal? 8. Why is strong tea or coffee injurious? 9. Should food or drink be taken hot? 10. Are fruitcakes, rich pastry, and puddings wholesome? 11. Why are warm biscuit and bread hard of digestion? 12. Should any stimulants be used in youth? 13. Why should bread be made spongy? 14. Which should remain longer in the mouth, bread or meat? 15. Why should cold water be used in making soup, and hot water in boiling meat? 16. Name the injurious effects of overeating. 17. Why do not buckwheat cakes, with syrup and butter, taste as well in July as in January? 18. Why is a late supper injurious? 19. What makes a man "bilious"? 20. What is the best remedy? _Ans_. Diet to give the organs rest, and active exercise to arouse the secretions and the circulation. 21. What is the practical use of hunger? 22. How can jugglers drink when standing on their heads? 23. Why do we relish butter on bread? 24. What would you do if you had taken arsenic by mistake? (See Appendix.) 25. Why should ham and sausage be thoroughly cooked? 26. Why do we wish butter on fish, eggs with tapioca, oil on salad, and milk with rice? 27. Explain the relation of food to exercise. 28. How do you explain the difference in the manner of eating between carnivorous and herbivorous animals? 29. Why is a child's face plump and an old man's wrinkled? 30. Show how life depends on repair and waste. 31. What is the difference between the decay of the teeth and the constant decay of the body? 32. Should biscuit and cake containing yellow spots of soda be eaten? 33. Tell how the body is composed of organs, how organs are made up of tissues, and how tissues consist of cells. 34. Why do we not need to drink three pints of water per day? 35. Why, during a pestilence, are those who use liquors as a beverage the first, and often the only victims? 36. What two secretions seem to have the same general use? 37. How may the digestive organs be strengthened? 38. Is the old rule, "after dinner sit awhile," a good one? 39. What would you do if you had taken laudanum by mistake? Paris Green? Sugar of lead? Oxalic acid? Phosphorus from matches? Ammonia? Corrosive sublimate? (See p. 265.) 40. What is the simplest way to produce vomiting, so essential in case of accidental poisoning? 41. In what way does alcohol interfere with the digestion? 42. Is alcohol assimilated? 43. What is the effect of alcohol on the albuminous substances? 44. Is there any nourishment in beer? 45. Show how the excessive use of alcohol may first increase, and, afterward, decrease, the size of the liver. 46. Will liquor help one to endure cold and exposure? 47. What is a fatty degeneration of the kidneys? 48. Contrast the action of alcohol and water in the body. 49. Is alcohol, in any proper sense of the term, a food? 50. Does liquor strengthen the muscles of a working man? 51. Is liquor a wholesome "tonic"? 52. Is it a good plan to take a glass of liquor before dinner? VII. THE NERVOUS SYSTEM. "Mark then the cloven sphere that holds All thoughts in its mysterious folds, That feels sensation's faintest thrill, And flashes forth the sovereign will; Think on the stormy world that dwells Lock'd in its dim and clustering cells; The lightning gleams of power it sheds Along its hollow, glassy threads!" "As a king sits high above his subjects upon his throne, and from it speaks behests that all obey, so from the throne of the brain cells is all the kingdom of a man directed, controlled, and influenced. For this occupant, the eyes watch, the ears hear, the tongue tastes, the nostrils smell, the skin feels. For it, language is exhausted of its treasures, and life of its experience; locomotion is accomplished, and quiet insured. When it wills, body and spirit are goaded like overdriven horses. When it allows, rest and sleep may come for recuperation. In short, the slightest penetration may not fail to perceive that all other parts obey this part, and are but ministers to its necessities."--Odd Hours of a Physician. ANALYSIS OF THE NERVOUS SYSTEM. _ | 1. THE STRUCTURE | _ | _ | 1. _Description._ | | 1. The Brain........| 2. _The Cerebrum._ | | |_3. _The Cerebellum._ | | _ | | 2. The Spinal Cord..| 1. _Its Composition._ | | |_2. _Medulla Oblongata._ | | _ | 2. ORGANS OF | | 1. _Description._ | THE NERV- | | 2. _Motory and Sensory._ | OUS SYSTEM..| | 3. _Transfer of Pain._ | | | 4. _The Spinal Nerves-- | | | 31 Pairs._ | |_3. The Nerves.......| 5. _The Cranial Nerves-- | | 12 Pairs._ | | 6. _Sympathetic System._ | | 7. _Crossing of Cords._ | | 8. _Reflex Action._ | | 9. _Uses of Reflex | |_ Action_ | _ | | 1. Brain Exercise. | | 2. Connection between Brain Growth and Body Growth. | 3. HYGIENE.....| 3. Sleep. | | 4. Effect of Sleeping Draughts. | |_5. Sunlight. | | 4. WONDERS OF THE BRAIN. | _ | | 1. Alcohol (Con'd.) | | _ | 1. _Stage of Excitement._ | || | 2. _Stage of Muscular | || | Weakness._ | || 1. Effect of Alco- | 3. _Stage of Mental | || hol upon the | Weakness._ | || Nervous System | 4. _Stage of Unconscious- | || |_ ness._ | || | || 2. Effect upon the Brain | ||_3. Effect upon the Mental and Moral Powers. | | | | 2. Tobacco. | | _ | || 1. Constituents of Tobacco. | 5. ALCOHOLIC || 2. Physiological Effects. | DRINKS AND|| 3. Possible Disturbances produced by Smoking. |_ NARCOTICS.|| 4. Influence upon the Nervous System. || 5. Is Tobacco a Food? ||_6. Influence of Tobacco on Youth. | _ | | 1. _Description._ | 3. Opium............| 2. _Physiological | |_ Effects._ | 4. Chloral Hydrate. | 5. Chloroform. |_6. Cocaine. THE NERVOUS SYSTEM. [Footnote: The organs of circulation, respiration, and digestion, of which we have already spoken, are often called the vegetative functions, because they belong also to the vegetable kingdom. Plants have a circulation of sap through their cells corresponding to that of the blood through the capillaries. They breathe the air through their leaves, which act the part of lungs, and they take in food which they change into their own structure by a process which answers to that of digestion. The plant, however, is a mere collection of parts incapable of any combined action. On the other hand, the animal has a nervous system which binds all the organs together.] STRUCTURE.--The nervous system includes the _brain_, the _spinal cord_, and the _nerves_. It is composed of two kinds of matter-- the _white_, and the _gray_. The former consists of minute, milk-white, glistening fibers, sometimes as small as 1/25000 of an inch in diameter; the latter is made up of small, ashen-colored cells, forming a pulp-like substance of the consistency of blancmange. [Footnote: In addition to the cells, the gray substance contains also nerve fibers continuous with the white fibers, but generally much smaller. These form half the bulk of the gray substance of the spinal cord, and a large part of the deeper layer of the gray matter in the brain.--LEIDY'S _Anatomy_, p. 507.] This is often gathered in little masses, termed ganglions (_ganglion_, a knot), because, when a nerve passes through a group of the cells, they give it the appearance of a knot. The nerve fibers are conductors, while the gray cells are generators, of nervous force. [Footnote: What this force is we do not know. In some respects it is like electricity, but, in others, it differs materially. Its velocity is about thirty three meters per second.--_Popular Physics_, p. 244, Note.] The ganglia, or nervous centers, answer to the stations along a telegraphic line, where messages are received and transmitted, and the fibers correspond to the wires that communicate between different parts. FIG. 50. [Illustration: _The Nervous System._ A, _cerebrum_; B, _cerebellum._] The BRAIN is the seat of the mind. [Footnote: In proportion to the rest of the nervous matter in the body, it is larger in man than in any of the lower animals. It is the function which the brain performs that distinguishes man from all other animals, and it is by the action of his brain that he becomes a conscious, intelligent, and responsible being. The brain is the seat of that knowledge which we express when we say _I_. I know it, I feel it, I saw it, are expressions of our individual consciousness, the seat of which is the brain. It is when the brain is at rest in sleep that there is least consciousness. The brain may be put under the influence of poisons, such as alcohol and chloroform, and then the body is without consciousness. From these and other facts the brain is regarded as the seat of _consciousness_.--LANKESTER.] Its average weight is about fifty ounces. [Footnote: Cuvier's brain weighed 64 1/2 ounces; Webster's, 53 1/2 ounces; James Fisk's, 58 ounces; Ruloff's, 59 ounces; an idiot's, 19 ounces. See Table in FLINT'S _Nervous System_.] It is egg-shaped, and, soft and yielding, fills closely the cavity of the skull. It reposes securely on a water bed, being surrounded by a double membrane _(arachnoid)_, delicate as a spider's web, which forms a closed sac filled, like the spaces in the brain itself, with a liquid resembling water. Within this, and closely investing the brain, is a fine tissue (_pia mater_), with a mesh of blood vessels which dips down into the hollows, and bathes them so copiously that it uses one fifth of the entire circulation of the body. Around the whole is wrapped a tough membrane (_dura mater_), which lines the bony box of the skull, and separates the various parts of the organ by strong partitions. The brain consists of two parts--the _cerebrum_, and the _cerebellum_. The CEREBRUM fills the front and upper part of the skull, and comprises about seven eighths of the entire weight of the brain. As animals rise in the scale of life, this higher part makes its appearance. It is a mass of white fibers, with cells of gray matter sprinkled on the outside, or lodged here and there in ganglia. It is so curiously wrinkled and folded as strikingly to resemble the meat of an English walnut. This structure gives a large surface for the gray matter,--sometimes as much as six hundred and seventy square inches. The convolutions are not noticeable in an infant, but increase with the growth of the mind, their depth and intricacy being characteristic of high mental power. FIG. 51. [Illustration: _Surface of the Cerebrum._] The cerebrum is divided into two hemispheres, connected beneath by fibers of white matter. Thus we have two brains, [Footnote: This doubleness has given rise to some curious speculations. In the case of the hand, eye, etc, we know that the sensation is made more sure. Thus we can see with one eye, but not so well as with both. It is perhaps the same with the brain. We may sometimes carry on a train of thought, "build an air castle" with one half of our brain, while the other half looks on and watches the operation; or, we may read and at the same time think of something else. So in delirium, a patient often imagines himself two persons, thus showing a want of harmony between the two halves.--DRAPER, _Human Physiology_, p. 320.] as well as two hands and two eyes. This provides us with a surplus of brains, as it were, which can be drawn upon in an emergency. A large part of one hemisphere has been destroyed without particularly injuring the mental powers, [Footnote: A pointed iron bar, three and a half feet long and one inch and a quarter in diameter, was driven by the premature blasting of a rock completely through the side of the head of a man who was present. It entered below the temple, and made its exit at the top of the forehead, just about the middle line. The man was at first stunned, and lay in a delirious, semistupefied state for about three weeks. At the end of sixteen months, however, he was in perfect health, with wounds healed and mental and bodily functions unimpaired, except that sight was lost in the eye of the injured side.-- DALTON. It is noticeable, however, that the man became changed in disposition, fickle, impatient of restraint, and profane, which he was not before. He died epileptic, nearly thirteen years after the injury. The tamping iron and the skull are preserved in the Warren Anatomical Museum, Boston.]--just as a person has been blind in one eye for a long time without having discovered his loss. The cerebrum is the center of intelligence and thought. [Footnote: In man, the cerebrum presents an immense preponderance in weight over other portions of the brain; in some of the lower animals, the cerebrum is even less in weight than the cerebellum. Another interesting point is the development of cerebral convolutions in certain animals, by which the relative amount of gray matter is increased. In fishes, reptiles, and birds, the surface of the hemispheres is smooth; but, in many mammalia, especially in those remarkable for intelligence, the cerebrum presents a greater or less number of convolutions, as it does in the human subject.--FLINT. The average weight of the human brain in proportion to the entire body is about 1 to 36. The average of mammalia is 1 to 186; of birds, 1 to 212; of reptiles, 1 to 1,321; and of fishes, 1 to 5,668. There are some animals in which the weight of the brain bears a higher proportion to the body than it does in man; thus in the blue-headed tit, the proportion is as 1 to 12; in the goldfinch, as 1 to 24; and in the field mouse, as 1 to 31. "It does not hence follow, however, that the _cerebrum_ is larger in proportion; in fact, it is probably not nearly so large; for in birds and rodent animals the sensory ganglia form a very considerable portion of the entire brain. M. Baillarger has shown that the _surface_ and the _bulk_ of the cerebral hemispheres are so far from bearing any constant proportion to each other in different animals that, notwithstanding the depth of the convolutions in the human cerebrum, its bulk is two and a half times as great in proportion to its surface as it is in the rabbit, the surface of whose cerebrum is smooth. The _size_ of the cerebrum, considered alone, is not, however, a fair test of its intellectual power. This depends upon the quantity of _vesicular matter_ which it contains, as evinced not only by superficial area, but by the number and depth of the convolutions and by the thickness of the cortical layer."--CARPENTER.] Persons in whom it is seriously injured or diseased often become unable to converse intelligently, both from inability to remember words and from loss of power to articulate them. THE CEREBELLUM lies below the cerebrum, and in the back part of the head (Fig. 50). It is about the size of a small fist. Its structure is similar to that of the brain proper, but instead of convolutions it has parallel ridges, which, letting the gray matter down deeply into the white matter within, give it a peculiar appearance, called the _arbor vitæ_, or tree of life (Fig. 55). This part of the brain is the center for the control of the voluntary muscles, [Footnote: The exact nature of the functions of the cerebellum is one of those problems concerning which there is no unanimity of opinion amongst physiologists. It may be premised, however, that the knowledge we at present possess does enable us to come to one very important conclusion with respect to the functions of the cerebellum,--it enables us to say that this organ has no independent function either in the province of mind or in the province of motility. And we may perhaps safely affirm still further, that the cerebellum is much more intimately concerned with the production of bodily movements than with the evolution of mental phenomena. The anatomical distinctness of the cerebellum from the larger brain and other parts of the nervous system is more apparent than real....That there is an habitual community of action between the cerebellum and the spinal cord is, I believe, doubted by none, and the fact that an intimate functional relationship exists between the cerebrum and the cerebellum is shown by the circumstance that atrophy of one cerebral hemisphere entails a corresponding atrophy of the opposite half of the cerebellum. The subordinate or supplementary nature of the cerebellar function, however, in this latter relation seems equally well shown by the fact that atrophy of one side of the cerebellum (when it occurs as the primary event) does not entail any appreciable wasting in the opposite half of the cerebrum. What other conclusion can be drawn? If the cutting off of certain cerebral stimuli leads to a wasting of the opposite half of the cerebellum, this would seem to show that each half of the cerebellum is naturally called into activity in response to, or conjointly with, the opposite cerebral hemisphere. Whilst conversely, if atrophy of one half of the cerebellum does not entail a relative diminution in the opposite cerebral hemisphere, this would go to show that the cerebral hemispheres do not act in response to cerebellar stimuli, since their nutrition does not suffer when such stimuli are certainly absent. The action of the cerebrum is therefore shown to be primary, whilst that of the cerebellum is secondary or subordinate in the performance of those functions in which they are both concerned.--H. CHARLTON BASTIAN, _Paralysis from Brain Disease_.] particularly those of locomotion. Persons in whom it is injured or diseased walk with tottering and uncertain movements as if intoxicated, and can not perform any orderly work. THE SPINAL CORD occupies the cavity of the backbone. It is protected by the same membranes as the brain, but, unlike it, the white matter is on the outside, and the gray matter is within. Deep fissures separate it into halves (Fig. 50), which are, however, joined by a bridge of the same substance. Just as it starts from the brain, there is an expansion called the _medulla oblongata_ (Fig. 55). THE NERVES are glistening, silvery threads, composed, like the spinal cord, of white matter without and gray within. They ramify to all parts of the body. Often they are very near each other, yet are perfectly distinct, each conveying its own impression. [Footnote: Press two fingers together, and, closing the eyes, let some one pass the point of a pin lightly from one to the other; you will be able to tell which is touched, yet if the nerves came in contact with each other anywhere in their long route to the brain, you could not thus distinguish.] Those which carry the orders of the mind to the different organs are called the _motory_ nerves; while those which bring back impressions which they receive are styled _sensory_ nerves. If the sensory nerve leading to any part be cut, all sensation in that spot will be lost, while motion will remain; if the motory nerve be cut, all motion will be destroyed, while sensation will exist as before. TRANSFER OF PAIN.--Strictly speaking, pain is not in any organ, but in the mind, since only that can feel. When any nerve brings news to the brain of an injury, the mind refers the pain to the end of the nerve. A familiar illustration is seen in the "funny bone" behind the elbow. Here the nerve (_ulnar_) gives sensation to the third and fourth fingers, in which, if this bone be struck, the pain will seem to be. Long after a limb has been amputated, pain will be felt in it, as if it still formed a part of the body--any injury in the stump being referred to the point to which the nerve formerly led. [Footnote: Only about five per cent. of those who suffer amputation lose the feeling of the part taken away. There is something tragical, almost ghastly, in the idea of a spirit limb haunting a man through his life, and betraying him in unguarded moments into some effort, the failure of which suddenly reminds him of his loss. A gallant fellow, who had left an arm at Shiloh, once, when riding, attempted to use his lost hand to grasp the reins while with the other he struck his horse. A terrible fall was the result of his mistake. When the current of a battery is applied to the nerves of an arm stump, the irritation is carried to the brain, and referred to all the regions of the lost limb. On one occasion a man's shoulder was thus electrized three inches above the point where the limb was cut off. For two years he had ceased to be conscious of his limb. As the electric current passed through, the man, who had been profoundly ignorant of its possible effects, started up, crying, "Oh, the hand! the hand!" and tried to seize it with the living grasp of the sound fingers. No resurrection of the dead could have been more startling.--DR. MITCHELL _on "Phantom Limbs" in Lippincott's Magazine_.] The nerves are divided into three general classes--the _spinal_, the _cranial_, and the _sympathetic_. FIG. 54. [Illustration: P, _posterior root of a spinal nerve;_ G, _ganglion;_ A, _anterior root;_ S, _spinal nerve. The white portions of the figure represent the white fibers; and the dark, the gray._] THE SPINAL NERVES, of which there are thirty-one pairs, issue from the spinal cord through apertures provided for them in the backbone. Each nerve arises by two roots; the anterior is the motory, and the posterior the sensory one. The posterior alone connects directly with the gray matter of the cord, and has a small ganglion of gray matter of its own at a little distance from its origin. These roots soon unite, _i. e_., are bound up in one sheath, though they preserve their special functions. When the posterior root of a nerve is cut, the animal loses the power of feeling, and when the anterior root is cut, that of motion. THE CRANIAL NERVES, twelve pairs in number, spring from the lower part of the brain and the medulla oblongata. 1. The _olfactory_, or first pair of nerves, ramify through the nostrils, and are the nerves of smell. 2. The _optic_, or second pair of nerves, pass to the eyeballs, and are the nerves of vision. 3, 4, 6. The _motores oculi_ (eye movers) are three pairs of nerves used to move the eyes. 5. The _trifacial_, or fifth pair of nerves, divide each into three branches--hence the name--the first to the upper part of the face, eyes, and nose; the second to the upper jaw and teeth; the third to the lower jaw and the mouth, where it forms the nerve of taste. These nerves are implicated when we have the toothache or neuralgia. 7. The _facial_, or seventh pair of nerves, are distributed over the face, and give it expression. [Footnote: If it is palsied, on one side there will be a blank, while the other side will laugh or cry, and the whole face will look funny indeed. There were some cruel people in the middle ages who used to cut the nerve and deform children's faces in this way, for the purpose of making money of them at shows. When this nerve was wrongly supposed to be the seat of neuralgia, or tic douloureux, it was often cut by surgeons. The patient suffered many dangers, and no relief of pain was gained.--MAPOTHER.] FIG. 55. [Illustration: _The Brain and the origin of the twelve pairs of Cranial Nerves._ F, E, _the cerebrum;_ D, _the cerebellum, showing the arbor vitæ;_ G, _the eye;_ H, _the medulla oblongata;_ A, _the spinal cord;_ C and B, _the first two pairs of spinal nerves._] 8. The _auditory_, or eighth pair of nerves, go to the ears, and are the nerves of hearing. 9. The _glos-so-pha-ryn'-ge-al_, or ninth pair of nerves, are distributed over the mucous membrane of the pharynx, tonsils, etc. 10. The _pneu-mo-gas'-tric_, or tenth pair of nerves, preside over the larynx, lungs, liver, stomach, and one branch extends to the heart. This is the only nerve which goes so far from the head. 11. The _accessory_, or eleventh pair of nerves, rise from the spinal cord, run up to the medulla oblongata, and thence leave the skull at the same opening with the ninth and tenth pairs. They regulate the vocal movements of the larynx. 12. The _hyp-o-glos'-sal_, or twelfth pair of nerves, give motion to the tongue. FIG. 56. [Illustration: _Spinal Nerve, Sympathetic Cord, and the Network of Sympathetic Nerves around the Internal Organs_. K, _aorta;_ A, _œophagus;_ B, _diaphragm;_ C, _stomach._] THE SYMPATHETIC SYSTEM contains the nerves of organic life. It consists of a double chain of ganglia on either side of the backbone, extending into the chest and abdomen. From, these, delicate nerves, generally soft and of a grayish color, run to the organs on which life depends--the heart, lungs, stomach, etc.--to the blood vessels, and to the spinal and cranial nerves over the body. Thus the entire system is bound together with cords of sympathy, so that, "if one member suffers, all the members suffer with it." Here lies the secret of the control exercised by the brain over all the vital operations. Every organ responds to its changing moods, especially those of respiration, circulation, digestion, and secretion,--processes intimately linked with this system, and controlled by it. (See p. 330.) CROSSING OF CORDS.--Each half of the body is presided over, not by its own half of the brain, but that of the opposite side. The motory nerves, as they descend from the brain, in the medulla oblongata, cross each other to the opposite side of the spinal cord. So the motor nerves of the right side of the body are connected with the left side of the brain, and _vice versa_. Thus a derangement in one half of the brain may paralyze the opposite half of the body. The nerves going to the face do not thus cross, and therefore the face may be motionless on one side, and the limbs on the other. Each of the sensory fibers of the spinal nerves crosses over to the opposite side of the spinal cord, and so ascends to the brain; an injury to the spinal cord may, therefore, cause a loss of motion in one leg and of feeling in the other. REFLEX ACTION.--Since the gray matter generates the nervous force, a ganglion is capable of receiving an impression, and of sending back or _reflecting_ it so as to excite the muscles to action. This is done without the consciousness of the mind. [Footnote: Instances of an unconscious working of the mind are abundant. An illustration, often quoted, is given, as follows, by Dr. Abercrombie, in his _Intellectual Powers_: "A lawyer had been excessively perplexed about a very complicated question. An opinion was required from him, but the question was one of such difficulty that he felt very uncertain how he should render it. The decision had to be given at a certain time, and he awoke in the morning of that day with a feeling of great distress. He said to his wife, 'I had a dream, and the whole thing was clearly arranged before my mind, and I would give anything to recover the train of thought.' His wife said to him, 'Go and look on your table.' She had seen him get up in the night and go to his table and sit down and write. He did so, and found there the opinion which he had been most earnestly endeavoring to recover, lying in his own handwriting. There was no doubt about it whatever." In this case the action of the brain was clearly automatic, _i. e._, reflex. The lawyer had worried his brain by his anxiety, and thus prevented his mind from doing its best. But it had received an impulse in a certain direction, and when left to itself, worked out the result. (See Appendix for other illustrations.)] Thus we wink involuntarily at a flash of light or a threatened blow. [Footnote: A very eminent chemist a few years ago was making an experiment upon some extremely explosive compound which he had discovered. He had a small quantity of this compound in a bottle, and was holding it up to the light, looking at it intently; and whether it was a shake of the bottle or the warmth of his hand, I do not know, but it exploded in his hand, and the bottle was shivered into a million of minute fragments, which were driven in every direction. His first impression was that they had penetrated his eyes, but to his intense relief he found presently that they had only struck the outside of his eyelids. You may conceive how infinitesimally short the interval was between the explosion of the bottle and the particles reaching his eyes; and yet in that interval the impression had been made upon his sight, the mandate of the reflex action, so to speak, had gone forth, the muscles of his eyelids had been called into action, and he had closed his eyelids before the particles had reached them, and in this manner his eyes were saved. You see what a wonderful proof this is of the way in which the automatic action of our nervous apparatus enters into the sustenance of our lives, and the protection of our most important organs from injury.-- DR. CARPENTER.] We start at a sudden sound. We jump back from a precipice before the mind has time to reason upon the danger. The spinal cord conducts certain impressions to the brain, but responds to others without troubling that organ. [Footnote: There is a story told of a man, who, having injured his spinal cord, had lost feeling and motion in his lower extremities. Dr. John Hunter experimented upon him. Tickling his feet, he asked him if he felt it; the man, pointing to his limbs, which were kicking vigorously about, answered, "No, but you see my legs do." Illustrations of this independent action of the spinal cord are common in animals. A headless wasp will ply its sting energetically. A fowl, after its head is cut off, will flap its wings and jump about as if in pain, although, of course, all sensation has ceased. "A water beetle, having had its head removed, remained motionless as long as it rested on a dry surface, but when cast into water, it executed the usual swimming motions with great energy and rapidity, striking all its comrades to one side by its violence, and persisting in these for more than half an hour."] The medulla oblongata carries on the process of respiration. The great sympathetic system binds together all the organs of the body. USES OF REFLEX ACTION.--We breathe eighteen times every minute; we stand erect without a consciousness of effort; [Footnote: In this way we account for the perilous feats performed by the somnambulist. He is not conscious, as his operations are not directed by the cerebrum, but by the other nervous centers. Were he to attempt their repetition when awake, the emotion of fear might render it impossible.] we walk, eat, digest, and at the same time carry on a train of thought. Our brain is thus emancipated from the petty detail of life. If we were obliged to attend to every breath, every pulsation of the heart, every wink of the eye, our time would be wasted in keeping alive. Mere standing would require our entire attention. Besides, an act which at first demands all our thought soon requires less, and at last becomes mechanical, [Footnote: "As every one knows," says Huxley, "it takes a soldier a long time to learn his drill-- for instance, to put himself into the attitude of 'attention' at the instant the word of command is heard. But, after a time, the sound of the word gives rise to the act, whether the soldier be thinking of it or not. There is a story, which is credible enough, though it may not be true, of a practical joker, who, seeing a discharged veteran carrying home his dinner, suddenly called out 'Attention!' whereupon the man instantly brought his hands down and lost his mutton and potatoes in the gutter. The drill had been thorough, and its effects had become embodied in the man's nervous structure."] as we say, _i. e._, reflex. Thus we play a familiar tune upon an instrument and carry on a conversation at the same time. All the possibilities of an education and the power of forming habits are based upon this principle. No act we perform ends with itself. It leaves behind it in the nervous centers a tendency to do the same thing again. Our physical being thus conspires to fix upon us the habits of a good or an evil life. Our very thoughts are written in our muscles, so that the expression of our face and even our features grow into harmony with the life we live. BRAIN EXERCISE.--The nervous system demands its life and activity. The mind grows by what it feeds on. One who reads mainly light literature, who lolls on the sofa or worries through the platitudes of an idle or fashionable life, decays mentally; his system loses tone, and physical weakness follows mental poverty. On the other hand, an excessive use of the mind withdraws force from the body, whose weakness, reacting on the brain, produces gradual decay and serious diseases. (See p. 331.) The brain grows by the growth of the body. The body grows through good food, fresh air, and work and rest in suitable proportion. For the full development and perfect use of a strong mind, a strong body is essential. Hence, in seeking to expand and store the intellect, we should be equally thoughtful of the growth and health of the body. SLEEP [Footnote: Sleep procured by medicine is rarely as beneficial as that secured naturally. The disturbance to the nervous system is often sufficient to counterbalance all the good results. The habit of seeking sleep in this way, without the advice of a physician, is to be most earnestly deprecated. The dose must be constantly increased to produce the effect, and thus great injury may be caused. Often, too, where laudanum or morphine is used, the person unconsciously comes into a terrible and fatal bondage. (See p. 342.) Especially should infants never be dosed with cordials, as is a common family practice. The damage done to helpless childhood by the ignorant and reckless use of soothing syrups is frightful to contemplate. All the ordinary sleeping draughts have life-destroying properties, as is proved by the fatal effects of an overdose. At the best, they paralyze the nerve centers, disorder the digestion, and poison the blood. Their promiscuous use is therefore full of danger.] is as essential as food. During the day, the process of tearing down goes on; during the night, the work of building up should make good the loss. In youth more sleep is needed than in old age, when nature makes few permanent repairs, and is content with temporary expedients. The number of hours required for sleep must be decided by each person. Napoleon took only five hours, but most people need from six to eight hours,--brain workers even more. In general, one should sleep until he naturally wakes. If one's rest be broken, it should be made up as soon as possible. (See p. 334.) SUNLIGHT.--The influence of the sun's rays upon the nervous system is very marked. [Footnote: The necessity of light for young children is not half appreciated. Many of their diseases, and nearly all the cadaverous looks of those brought up in great cities, are ascribable to the deficiency of light and air. When we see the glass room of the photographers in every street, in the topmost story, we grudge them their application to what is often a mere personal vanity. Why should not a nursery be constructed in the same manner? If parents knew the value of light to the skin, especially to children of a scrofulous tendency, we should have plenty of these glass house nurseries, where children might run about in a proper temperature, free from much of that clothing which at present seals up the skin--that great supplementary lung--against sunlight and oxygen. They would save many a weakly child who now perishes from lack of these necessaries of infant life.--DR. WINTER.] It is said also to have the effect of developing red disks in the blood. All vigor and activity come from the sun. Vegetables grown in subdued light have a bleached and faded look. An infant kept in absolute darkness would grow into a shapeless idiot. That room is the healthiest to which the sun has the freest access. Epidemics frequently attack the inhabitants of the shady side of a street, and exempt those on the sunny side. If, on a slight indisposition, we should go out into the open air and bright sunlight, instead of shutting ourselves up in a close, dark chamber, we might often avoid a serious illness. The sun bath is doubtless a most efficient remedy for many diseases. Our window blinds and curtains should be thrown back and open, and we should let the blessed air and sun stream in to invigorate and cheer. No house buried in shade, and no room with darkened windows, is fit for human habitation. In damp and darkness, lies in wait almost every disease to which flesh is heir. The sun is their only successful foe. (See p. 336.) WONDERS OF THE BRAIN.--After having seen the beautiful contrivances and the exquisite delicacy of the lower organs, it is natural to suppose that when we come to the brain we should find the most elaborate machinery. How surprising, then, it is to have revealed to us only cells and fibers! The brain is the least solid and most unsubstantial looking organ in the body. Eighty per cent of water, seven of albumen, some fat, and a few minor substances constitute the instrument which rules the world. Strangest of all, the brain, which is the seat of sensation, is itself without sensation. Every nerve, every part of the spinal cord, is keenly alive to the slightest touch, yet "the brain may be cut, burned, or electrified without producing pain." ALCOHOLIC DRINKS AND NARCOTICS. ALCOHOL (Continued from p. 187). EFFECT UPON THE NERVOUS SYSTEM.--In the progressive influence of alcohol upon the nervous system, there are, according to the researches of Dr. Richardson, four successive stages. 1. THE STAGE OF EXCITEMENT. [Footnote: The pupil should be careful to note here that alcohol does not act upon the heart directly, and cause it to contract with more force. The idea that alcohol gives energy and activity to the muscles is entirely false. It really, as we have seen (p. 183), weakens muscular contraction. The enfeeblement begins in the first stage, and continues in the other stages with increased effect. The heart beats quickly merely because the resistance of the minute controlling vessels is taken off, and it works without being under proper regulation. _What is called a stimulation or excitement is, in absolute fact, a relaxation, a partial paralysis_ of one of the most important mechanisms in the animal body. Alcohol should be ranked among the narcotics.--RICHARDSON.]-- The first effect of alcohol, as we have already described on page 144, is to paralyze the nerves that lead to the extreme and minute blood vessels, and so regulate the passage of the blood through the capillary system. The vital force, thus drawn into the nervous centers, drives the machinery of life with tremendous energy. The heart jumps like the mainspring of a watch when the resistance of the wheels is removed. The blood surges through the body with increased force. Every capillary tube in the system is swollen and flushed, like the reddened nose and cheek. In all this there is exhilaration, but no nourishment; there is animation, but no permanent power conferred on brain or muscle. Alcohol may cheer for the moment. It may set the sluggish blood in motion, start the flow of thought, and excite a temporary gayety. "It may enable a wearied or feeble organism to do brisk work for a short time. It may make the brain briefly brilliant. It may excite muscle to quick action, but it does nothing at its own cost, fills up nothing it has destroyed, and itself leads to destruction." Even the mental activity it has excited is an unsafe state of mind, for that just poise of the faculties so essential to good judgment is disturbed by the presence of the intruder. Johnson well remarked, "Wine improves conversation by taking the edge off the understanding." 2. THE STAGE OF MUSCULAR WEAKNESS.--If the action of the alcohol be still continued, the spinal cord is next affected by this powerful narcotic. The control of some of the muscles is lost. Those of the lower lip usually fail first, then those of the lower limbs, and the staggering, uncertain steps betray the result. The muscles themselves, also, become feebler as the power of contraction diminishes. The temperature, which, for a time, was slightly increased, soon begins to fall as the heat is radiated; the body is cooled, and the well-known "alcoholic chill" is felt. 3. THE STAGE OF MENTAL WEAKNESS.--The cerebrum is now implicated. The ideal and emotional faculties are quickened, while the will is weakened. The center of thought being overpowered, the mind is a chaos. Ideas flock in thick and fast. The tongue is loosened. The judgment loses its hold on the acts. The reason giving way, the animal instincts generally assume the mastery of the man. The hidden nature comes to the surface. All the gloss of education and social restraint falls off, and the lower nature stands revealed. The coward shows himself more craven, the braggart more boastful, the bold more daring, and the cruel more brutal. The inebriate is liable to become the perpetrator of any outrage that the slightest provocation may suggest. 4. THE STAGE OF UNCONSCIOUSNESS.--At last, prostration ensues, and the wild, mad revel of the drunkard ends with utter senselessness. In common speech, the man is "dead drunk." Brain and spinal cord are both benumbed. Fortunately, the two nervous centers which supply the heart and the diaphragm are the slowest to be influenced. So, even in this final stage, the breathing and the circulation still go on, though the other organs have stopped. Were it not for this, every person thoroughly intoxicated would die. [Footnote: Cold has a wonderful influence in hastening this stage, so that a person, previously only in the first stage of excitement, on going outdoors on a winter night, may rapidly sink into a lethargy (become _comatose_), fall, and die. He is then commonly said to have perished with cold. The signs of this coma are of great practical importance, since so many persons die in police stations and elsewhere who are really comatose, when they are supposed to be only sound asleep. The pulse is slow, and almost imperceptible. The face is pale, and the skin cold. "If the arm be pinched, it is not moved; if the eyeballs are touched, the lids will not sink." The respiration becomes slower and slower, and, if the person dies, it is because liquid collects in the bronchial tubes, and stops the passage of the air. The man then actually drowns in his own secretions.] EFFECT UPON THE BRAIN.--Alcohol seems to have a special affinity for the brain. This organ absorbs more than any other, and its delicate structure is correspondingly affected. The "Vascular enlargement" here reaches its height. The tiny vessels become clogged with blood that is unfitted to nourish, because loaded with carbonic acid, and deprived of the usual quantity of the life-giving oxygen.--HINTON. The brain is, in the language of the physiologist, malfunctioned. The mind but slowly rallies from the stupor of the fourth stage, and a sense of dullness and depression remains to show with what difficulty the fatigued organ recovers its normal condition. So marked is the effect of the narcotic poison, that some authorities hold that "a once thoroughly intoxicated brain never fully becomes what it was before." In time, the free use of liquor hardens and thickens the membrane enveloping the nervous matter; the nerve corpuscles undergo a "Fatty degeneration"; the blood vessels lose their elasticity; and the vital fluid, flowing less freely through the obstructed channels, fails to afford the old-time nourishment. The consequent deterioration of the nervous substance--the organ of thought--shows itself in the weakened mind [Footnote: The habitual use of fermented liquors, even to an extent far short of what is necessary to produce intoxication, injures the body, and diminishes the mental power.--Sir Henry Thompson.] that we so often notice in a person accustomed to drink, and at last lays the foundation of various nervous disorders--epilepsy, paralysis, and insanity. [Footnote: Casper, the great statistician of Berlin, says: "So far as that city is concerned, one third of the insane coming from the poorer classes, were made so by spirit drinking."] The law of heredity here again asserts itself, and the inebriate's children often inherit the disease which he has escaped. Chief among the consequences of this perverted and imperfect nutrition of the brain is that intermediate state between intoxication and insanity, well known as Delirium Tremens. "It is characterized by a low, restless activity of the cerebrum, manifesting itself in muttering delirium, with occasional paroxysms of greater violence. The victim almost always apprehends some direful calamity; he imagines his bed to be covered with loathsome reptiles; he sees the walls of his apartment crowded with foul specters; and he imagines his friends and attendants to be fiends come to drag him down to a fiery abyss beneath."--CARPENTER. (See p. 287.) INFLUENCE UPON THE MENTAL AND MORAL POWERS.--So intimate is the relation between the body and the mind, that an injury to one harms the other. The effect of alcoholized blood is to weaken the will. The one habitually under its influence often shocks us by his indecision and his readiness to break a promise to reform. The truth is, he has lost, in a measure, his power of self-control. At last, he becomes physically unable to resist the craving demand of his morbid appetite. Other faculties share in this mental wreck. The intellectual vision becomes less penetrating, the decisions of the mind less reliable, and the grasp of thought less vigorous. The logic grows muddy. A thriftless, reckless feeling is developed. Ere long, self-respect is lost, and then ambition ceases to allure, and the high spirit sinks. Along with this mental deterioration comes also a failure of the moral sense. The fine fiber of character undergoes a "degeneration" as certain as that of the muscles themselves. Broken promises tell of a lowered standard of veracity, and a dulled sense of honor, quite as much as of an impaired will. Under the subtle influence of the ever-present poison, signs of spiritual weakness multiply fast. Conscience is lulled to rest. Reason is enfeebled. Customary restraints are easily thrown off. The sensibilities are blunted. There is less ability to appreciate nice shades of right and wrong. Great moral principles and motives lose their power to influence. The judgment fools with duty. The future no longer reaches back its hand to guide the present. The better nature has lost its supremacy. The wretched victim of appetite will now gratify his tyrannical passion for drink at any expense of deceit or crime. He becomes the blind instrument of his insane impulses, and commits acts from which he would once have shrunk with horror. [Footnote: Richardson sums up the various diseases caused by alcohol, as follows: "(_a_). Diseases of the brain and nervous system, indicated by such names as apoplexy, epilepsy, paralysis, vertigo, softening of the brain, delirium tremens, dipsomania or inordinate craving for drink, loss of memory, and that general failure of the mental power, called dementia. (_b_). Diseases of the lungs: one form of consumption, congestion, and subsequent bronchitis. (_c_). Diseases of the heart: irregular beat, feebleness of the muscular walls, dilatation, disease of the valves. (_d_). Diseases of the blood: scurvy, excess of water or dropsy, separation of fibrin. (_e_). Diseases of the stomach: feebleness of the stomach, indigestion, flatulency, irritation, and sometimes inflammation. (_f_). Diseases of the bowels: relaxation or purging, irritation. (_g_). Diseases of the liver: congestion, hardening and shrinking, cirrhosis. (_h_). Diseases of the kidneys: change of structure into fatty or waxy-like condition and other results leading to dropsy, or sometimes to fatal sleep. (_i_). Diseases of the muscles: fatty change in the muscles, by which they lose their power for proper active contraction. (_j_). Diseases of the membranes of the body: thickening and loss of elasticity, by which the parts wrapped up in the membrane are impaired for use, and premature decay is induced."] Sometimes he even takes a malignant pleasure in injuring those whom Nature has ordained he should protect. [Footnote: It has been argued that a man should not be punished for any crime he may commit during intoxication, but rather for knowingly giving up the reins of reason and conscience, and thus subjecting himself to the rule of his evil passions. Voluntarily to stimulate the mind and put it into a condition where it may drive one to ruin, is very like the act of an engineer who should get up steam in his engine, and then, having opened the valves, desert his post, and let the monster go thundering down the track to sure destruction. Certain persons are thrown into the stage of mental weakness by a single glass of liquor. How can they be excused when the fact of their peculiar liability lends additional force to the argument of abstemiousness, and they know that their only safety lies in total abstinence?--CARPENTER'S _Physiology._] 2. TOBACCO. The Constituents of Tobacco Smoke are numerous, but the prominent ones are carbonic-acid, carbonic-oxide, and ammonia gases; carbon, or soot; and nicotine. The proportion of these substances varies with different kinds of tobacco, the pipe used, and the rapidity of the combustion. Carbonic acid tends to produce sleepiness and headache. Carbonic oxide, in addition, causes a tremulous movement of the muscles, and so of the heart. Ammonia bites the tongue of the smoker, excites the salivary glands, and causes dryness of the mouth and throat. Nicotine is a powerful poison. The amount contained in one or two strong cigars, if thrown directly into the blood, would cause death. Nicotine itself is complex, yielding a volatile substance that gives the odor to the breath and clothing; and also a bitter extract which produces the sickening taste of an old pipe. In smoking, some of the nicotine is decomposed, forming pyridine, picoline, and other poisonous alkaloids. [Footnote: The analysis of tobacco as given by different authorities varies greatly. The one stated in the text suffices for the purposes of this chapter. Von Eulenberg names several other products of the combustion. One hundred pounds of the dry leaf may yield as high as seven pounds of nicotine. Havana tobacco contains about two per cent, and Virginia about six per cent.--See JOHNSTON & CHURCH'S _Chemistry of Common Life_, and MILLER'S _Organic Chemistry_.] PHYSIOLOGICAL EFFECTS.--The poison of tobacco, set free by the process either of chewing or smoking, when for the first time it is swept through the system by the blood, powerfully affects the body. Nausea is felt, and the stomach seeks to throw off the offending substance. The brain is inflamed, and headache follows. The motor nerves becoming irritated, giddiness ensues. Thus Nature earnestly protests against the formation of this habit. But, after repeated trials, the system adjusts itself to the new conditions. A "tolerance" of the poison is finally established, and smoking causes none of the former symptoms. Such powerful substances can not, however, be constantly inhaled without producing marked changes. The three great eliminating organs--the lungs, the skin, and the kidneys-- throw off a large part of the products, but much remains in the system. When the presence of the poison is constant, and especially when the smoking or chewing is excessive, the disturbance that at first is merely functional, must necessarily, in many cases at least, lead to a chronic derangement. Probably in this, as in the case of other deleterious articles of diet, the strong and healthy will seem to escape entirely, while the weak and those predisposed to disease will be injured in direct proportion to the extent of the indulgence. Those whose employment leads to active, outdoor work, will show no sign of nicotine poisoning, while the man of sedentary habits will sooner or later be the victim of dyspepsia, sleeplessness, nervousness, paralysis, or other organic difficulties. Even where the user of tobacco himself escapes harm, the law of heredity asserts itself, and the innocent offspring only too often inherit an impaired constitution, and a tendency to nervous complaints. THE VARIOUS DISTURBANCES produced in different individuals and constitutions by smoking have been summed up by Dr. Richardson as follows: "(_a_) In the blood, it causes undue fluidity, and change in the red corpuscles; (_b_) in the stomach, it gives rise to debility, nausea, and vomiting; (_c_) in the mucous membrane of the mouth, it produces enlargement and soreness of the tonsils--smoker's sore throat--redness, dryness, and occasional peeling of the membrane, and either unnatural firmness and contraction, or sponginess of the gums; and, where the pipe rests on the lips, oftentimes 'epithelial cancer'; (_d_) in the heart, it causes debility of the organ, and irregular action; (_e_) in the bronchial surface of the lungs, when that is already irritable, it sustains irritation, and increases the cough; (_f_) in the organs of sense, it produces dilation of the pupils of the eye, confusion of vision, bright lines, luminous or cobweb specks, and long retention of images on the retina, with analogous symptoms affecting the ear, viz., inability to define sounds clearly, and the occurrence of a sharp, ringing noise like a whistle; (_g_) in the brain, it impairs the activity of the organ, oppressing it if it be nourished, but soothing it if it be exhausted; (_h_) it leads to paralysis in the motor and sympathetic nerves, and to over-secretion from the glands which the sympathetic nerves control." IS TOBACCO A FOOD?--Here, as in the case of alcohol, the reply is a negative one. Tobacco manifests no characteristic of a food. It can not impart to the blood an atom of nutritive matter for building up the body. It does not add to, but rather subtracts from, the total vital force. It confers no potential power upon muscle or brain. It stimulates by cutting off the nervous supply from the extremities and concentrating it upon the centers. But stimulation is not nourishment; it is only a rapid spending of the capital stock. There is no greater error than to mistake the exciting of an organ for its strengthening. THE INFLUENCE UPON YOUTH.--Here, too, science utters no doubtful voice. Experience asserts only one conviction. _Tobacco retards the development of mind and body._ [Footnote: Cigarettes are especially injurious from the irritating smoke of the paper covering, taken into the lungs, and also because the poison fumes of the tobacco are more directly inhaled. In case of the cheap cigarettes often smoked by boys the ingredients used are harmful, while one revolts at the thought of the filthy materials, refuse cigar stumps, etc., employed in their manufacture.] The law of nature is that of steady growth. It can not admit of a daily, even though it be merely a functional, disturbance that weakens the digestion, that causes the heart to labor excessively, that prevents the perfect oxidation of the blood, that interferes with the assimilation, and that deranges the nervous system. [Footnote: There is one influence of tobacco that every young man should understand. In many cases, like alcohol, it seems to blunt the sensibilities, and to make its user careless of the rights and feelings of others. This is often noticed in common life. We meet everywhere "devotees of the weed," who, ignoring the fact that tobacco is disagreeable to many persons, think only of the gratification of their selfish appetite. They smoke or chew in any place or company. They permit the cigar fumes to blow into the faces of passers-by. They sit where the wind carries the smoke of their pipes so that others must inhale it. They expectorate upon the floor of cars, hotels, and even private homes. They take no pains to remove the odor that lingers about their person and clothing. They force all who happen to be near, their companions, their fellow-travelers, to inhale the nauseating odor of tobacco. Everything must be sacrificed to the one primal necessity of such persons--a smoke. Now, a young man just beginning life, with his fortune to make, and his success to achieve, can not afford to burden himself with a habit that is costly, that will make his presence offensive to many persons, and that may perhaps render him less sensitive to the best influences and perceptions of manhood.] No one has a right thus to check and disturb continually the regular processes of his physical and mental progress. Hence, the young man (especially if he be of a nervous, sensitive organization) who uses tobacco deliberately diminishes the possible energy with which he might commence the work of life; [Footnote: In the Polytechnic School at Paris, the pupils were divided into two classes--the smokers, and the non-smokers. The latter not only excelled on the entrance examinations, but during the entire course of study. Dr. Decaisne examined thirty-eight boys who smoked, and found twenty-seven of them diseased from nicotine poisoning. So long ago as 1868, in consequence of these results, the Minister of Public Instruction forbade the use of tobacco by the pupils. Dr. Gihon, medical director of the Naval Academy at Annapolis, in his report for 1881, says: "The most important matter in the health history of the students is that relating to tobacco, and its interdiction is absolutely essential to their future health and usefulness. In this view I have been sustained by my colleagues, and by all sanitarians in civil and military life whose views I have been able to obtain."] while he comes under the bondage of a habit that may become stronger than his will, and under the influence of a narcotic that may beguile his faculties and palsy his strength at the very moment when every power should be awake. Another peril still lies in the wake of this masterful poison habit. Tobacco causes thirst and depression that only too often and naturally lead to the use of liquor. (See p. 338.) 3. OPIUM. Opium is the dried juice of the poppy. In Eastern countries, this flower is cultivated in immense fields for the sake of this product. When a cut is made in the poppy head, a tiny tear of milky juice exudes, and hardens. These little drops are gathered and prepared for the market, an acre yielding, it is said, about twenty-five pounds. Throughout the East, opium is generally smoked; but in Western countries laudanum and paregoric (tinctures of opium), and morphine--a powerful alkaloid contained in opium, are generally used. The drug itself is also eaten. PHYSIOLOGICAL EFFECT.--Opium, in its various forms, acts directly upon the nerves, a small dose quieting pain, and a larger one soothing to sleep. It arouses the brain, and fires the imagination to a wonderful pitch. [Footnote: So far as its effects are concerned, it matters little in what form opium is taken, whether solid as in pills, liquid as in laudanum, or vaporized, as when inhaled from a pipe. The opium slave is characterized by trembling steps, a curved spine, sunken glassy eyes, sallow withered features, and often by contraction of the muscles of the neck and fingers. In the East, when the drug ceases its influence, the opium eater renews it with corrosive sublimate till, finally, this also fails of effect, and he gradually sinks into the grave.] The reaction from this unnatural excitant is correspondingly depressing; and the melancholy, the "overwhelming horror" that ensues, calls for a renewal of the stimulus. The dose must be gradually increased to produce the original exhilaration. [Footnote: The victim of opium is bound to a drug from which he derives no benefits, but which slowly deprives him of health and happiness, finally to end in idiocy or premature death. Whatever the victim's condition or surroundings may be, the opium must be taken at certain times with inexorable regularity. The liquor or tobacco user can, for a time, go without the use of these agents, and no regular hours are necessary. During sickness, and more especially during the eruptive fevers, he does not desire tobacco or liquor. The opium eater has no such reprieves; his dose must be taken, and, in painful complications affecting the stomach, a large increase is demanded to sustain the system. If, in forming the habit, two doses are taken each day, the victim is obliged to maintain that number. It is the unceasing, everlasting slavery of regularity that humiliates opium eaters by a sense of their own weakness.--HUBBARD _on The Opium Habit and Alcoholism._] The seductive nature of the drug leads the unfortunate victim on step by step until he finds himself fast bound in the fetters of one of the most tyrannical habits known to man. To go on is to wreck all one's powers--physical and mental. To throw off the habit, requires a determination that but few possess. Yet even when the custom is broken, the system is long in recovering from the shock. There seems to be a failure of every organ. The digestion is weakened, food is no longer relished, the muscles waste, the skin shrivels, the nervous centers are paralyzed, and a premature old age comes on apace. De Quincey, four months after he had cast away the opium bonds, wrote, "Think of me as one still agitated, writhing, throbbing, palpitating, shattered." No person can be too careful in the use of laudanum, paregoric, and morphine. They may be taken on a physician's prescription as a sedative from racking pain, [Footnote: Many persons learn to inject morphine beneath the skin by means of a "hypodermic syringe." The operation is painless, and seems an innocent one. It throws the narcotic directly into the circulation, and relief from pain is often almost instantaneous. But the danger of forming the opium habit is not lessened, and the effect of using the drug in this form for a long time is just as injurious as opium smoking itself. Opium in one of its forms enters largely into the composition of many of the painkillers and patent medicines so freely advertised for domestic use in the present day, and for this reason the greatest care is needed in having recourse to any of them. Taken, perhaps, in the first instance, to alleviate the torments of neuralgia or toothache, what proves to be a remedy soon becomes a source of gratification, which the wretchedness that follows on abstinence renders increasingly difficult to lay aside. The same must be said of bromide of potassium and hydrate of chloral, frequently resorted to as a remedy for sleeplessness: the system quickly becomes habituated to their use, and they can then be relinquished only at the cost of much suffering. Indeed, the last mentioned of these two drugs obtains over the mind a power which may be compared to that of opium, and is, moreover, liable to occasion the disease known as chloralism, by which the system ultimately becomes a complete wreck. Looking at the whole question of the medicinal use of narcotics, it is perhaps not too much to say that they should never be employed except with the authority of a competent medical adviser.-- _Chambers's Journal_.] but if followed up for any length of time, the powerful habit may be formed ere one is aware. Then comes the opium eater's grave, or the opium eater's struggle for life! 4. CHLORAL HYDRATE. CHLORAL HYDRATE is a drug frequently used to cause sleep. It leaves behind no headache or lassitude, as is often the case with morphine. It is, however, a treacherous remedy. It is cumulative in its effects, _i. e._, even a small and harmless dose, persisted in for a long period, may produce a gradual accumulation of evil results that in the end will prove fatal. THE PHYSIOLOGICAL EFFECT of its prolonged use is very marked. The appetite becomes capricious. The secretions are unnatural. Nausea and flatulency often ensue. Then the nervous system is involved. The heart is affected. Sleep, instead of responding to the drug, as at first, is broken and disturbed. The eyesight fails. The circulation is enfeebled, and the pulse becomes weak, rapid, and irregular. There is a tendency to fainting and to difficult respiration. Sometimes the impoverished blood induces a disease resembling scurvy, the ends of the fingers ulcerate, and the face is disfigured by blotches. An excessive dose may result in death. Prolonged habitual use of chloral hydrate tends to debase the mind and morals of the subject in the same manner as indulgence in alcohol, ether, or chloroform. 5. CHLOROFORM. CHLOROFORM is an artificial product generally obtained, by distillation, from a mixture of chloride of lime, water, and alcohol. It was discovered in 1831 by Samuel Guthrie, of Sackett's Harbor, New York. It is a colorless, transparent volatile liquid, with a strong ethereal odor. PHYSIOLOGICAL EFFECT.--Chloroform is a powerful anæsthetic, which, when inhaled, causes a temporary paralysis of the nervous system, and thus a complete insensibility to pain. There is great peril attending its use, even in the hands of the most skillful and experienced practitioners. It is sometimes prescribed by a physician, and afterward (as in the case of laudanum, morphine, and chloral) the sufferer, charmed with the release from pain and the peaceful slumber secured, buys the Lethean liquid for himself. Its use soon becomes an apparent necessity. The craving for the narcotic at a stated time is almost irresistible. The patient, compelled to give up the use of chloroform, will demand, entreat, pray for another dose, in a heartrending manner, never to be forgotten. Paleness and debility, the earliest symptoms, are followed by mental prostration. Familiarity with this dangerous drug begets carelessness, and its victims are frequently found dead in their beds, with the handkerchief from which they inhaled the volatile poison clutched in their lifeless hands. 6. COCAINE. Cocaine is an alkaloid prepared from the erythroxylon coca, a shrub, five or six feet high, found wild in the mountainous regions of Ecuador and Peru, where it is also cultivated by the natives. The South American Indians, for centuries, have chewed coca leaves as a stimulant, but the highly poisonous principle, now called cocaine, to which the plant owes its peculiar effects, was not discovered till 1859. Within a few years this drug has come into favor as an agent to produce local anæsthesia, and has proved exceedingly valuable in surgical operations upon the eye and other sensitive organs. It has already, however, been diverted from its legitimate use as a benefaction, and to the other evils of the day is now added the "cocaine habit," which is, perhaps, even more dangerous and difficult to abandon than either the alcohol or the opium habit. PHYSIOLOGICAL EFFECT.--Applied locally, cocaine greatly lessens and even annihilates pain. Taken internally, it acts as a powerful stimulant to the nervous system, its physiological action being similar to that of theine (p. 170), caffeine, and theobromine. Used hypodermically, its immediate effect, says one to whom it was thus administered, is to cause "great pallor of countenance, profuse frontal perspiration, sunken eyes, enlarged pupils, lessened sensitiveness of the cornea and conjunctiva, lowered arterial tension, and a feeble pulse and heart beat. Under its influence I could not reason. Everything seemed to run through my brain, and in vain I summoned all my will power to overcome an overwhelming sleepiness." A few doses of this drug will in some persons produce temporary insanity. Used to excess, it leads to permanent madness or idiocy. "Cocaine," says a writer in the _Medical Review_, "is a dangerous therapeutic toy not to be used as a sensational plaything. If it should come into as general use as the other intoxicants of its class, it will help to fill the asylums, inebriate and insane." PRACTICAL QUESTIONS. 1. Why is the pain of incipient hip disease frequently felt in the knee? 2. Why does a child require more sleep than an aged person? 3. When you put your finger in the palm of a sleeping child, why will he grasp it? 4. How may we strengthen the brain? 5. What is the object of pain? 6. Why will a blow on the stomach sometimes stop the heart? 7. How long will it take for the brain of a man six feet high to receive news of an injury to his foot, and to reply? 8. How can we grow beautiful? 9. Why do intestinal worms sometimes affect a child's sight? 10. Is there any indication of character in physiognomy? 11. When one's finger is burned, where is the ache? 12. Is a generally closed parlor a healthful room? 13. Why can an idle scholar read his lesson and at the same time count the marbles in his pocket? 14. In amputating a limb, what part, when divided, will cause the keenest pain? 15. What is the effect of bad air on nervous people? 16. Is there any truth in the proverb that "he who sleeps dines"? 17. What does a high, wide forehead indicate? 18. How does indigestion frequently cause a headache? 19. What is the cause of one's foot being "asleep"? [Footnote: Here the nervous force is prevented from passing by compression. Just how this is done, or what is kept from passing, we can not tell. If a current of electricity were moving through a rubber tube full of mercury, a slight squeeze would interrupt it. These cases may depend on the same general principle, but we can not assert it.--HUXLEY. The tingling sensation caused by the compression is transferred to the foot, whence the nerve starts.] 20. When an injury to the nose has been remedied by transplanting skin from the forehead, why is a touch to the former felt in the latter? 21. Are closely curtained windows healthful? 22. Why, in falling from a height, do the limbs instinctively take a position to defend the important organs? 23. What causes the pylorus to open and close at the right time? 24. Why is pleasant exercise most beneficial? 25. Why does grief cause one to lose his appetite? 26. Why should we never study directly after dinner? 27. What produces the peristaltic movement of the stomach? 28. Why is a healthy child so restless and full of mischief? 29. Why is a slight blow on the back of a rabbit's neck fatal? 30. Why can one walk and carry on a conversation at the same time? 31. What are the dangers of overstudy? 32. What is the influence of idleness upon the brain? 33. State the close relation which exists between physical and mental health and disease. 34. In what consists the value of the power of habit? 35. How many pairs of nerves supply the eye? 36. Describe the reflex actions in reading aloud. 37. Under what circumstances does paralysis occur? 38. If the eyelids of a profound sleeper were raised, and a candle brought near, would the iris contract? 39. How does one cough in his sleep? 40. Give illustrations of the unconscious action of the brain. 41. Is chewing tobacco more injurious than smoking? 42. Ought a man to retire from business while his faculties are still unimpaired? 43. Which is the more exhaustive to the brain, worry or severe mental application? 44. Is it a blessing to be placed beyond the necessity for work? 45. Show how anger, hate, and the other degrading passions are destructive to the brain. [Footnote: "One of the surest means for keeping the body and mind in perfect health consists in learning to hold the passions in subservience to the reasoning faculties. This rule applies to every passion. Man, distinguished from all other animals by the peculiarity that his reason is placed above his passions to be the director of his will, can protect himself from every mere animal degradation resulting from passionate excitement. The education of the man should be directed not to suppress such passions as are ennobling, but to bring all under governance, and specially to subdue those most destructive passions, anger, hate, and fear."] 46. Are not amusements, to repair the waste of the nervous energy, especially needed by persons whose life is one of care and toil? 47. Is not severe mental labor incompatible with a rapidly growing body? 48. How shall we induce the system to perform all its functions regularly 49. How does alcohol interfere with the action of the nerves? 50. What is the general effect of alcohol upon the character? 51. Does alcohol tend to produce clearness and vigor of thought? 52. What is the general effect of alcohol on the muscles? 53. Does alcohol have any effect on the bones? The skin? 54. What is the cause of the "alcoholic chill"? 55. Show how alcohol tends to develop man's lower, rather than his higher, nature. 56. When we wish really to strengthen the brain, should we use alcohol? 57. Why is alcohol used to preserve anatomical specimens? 58. What is meant by an inherited taste for liquor? 59. Ought a person to be punished for a crime committed during intoxication? 60. Should a boy ever smoke? 61. To what extent are we responsible for the health of our body? 62. Why does alcohol tend to collect in the brain? 63. Does the use of alcohol tend to increase crime and poverty? VIII. THE SPECIAL SENSES. "See how yon beam of seeming white Is braided, out of seven-hued light; Yet in those lucid globes no ray By any chance shall break astray. Hark, how the rolling surge of sound, Arches and spirals circling round, Wakes the hush'd spirit through thine ear With music it is heaven to hear." HOLMES. "Let us remember that if we get a glimpse of the details of natural phenomena, and of those movements which constitute life, it is not in considering them as a whole, but in analyzing them as far as our limited means will permit. In the vibrations of the globe of air which surrounds our planet, as in the undulations of the ether which fills the immensity of space, it is always by molecules which are intangible for us, put in motion by nature, always by the infinitely little, that she acts in exciting the organs of sense, and she has modeled these organs in a proportion which enables them to partake in the movement which she impresses upon the universe. She can paint with equal facility on a fraction of a line of space on the retina, the grandest landscape or the nervelets of a rose leaf; the celestial vault on which Sirius is but a luminous point, or the sparkling dust of a butterfly's wing; the roar of the tempest, the roll of thunder, the echo of an avalanche, find equal place in the labyrinth whose almost imperceptible cavities seem destined to receive only the most delicate sounds." _ _ | 1. THE TOUCH...| 1. Description of the Organ. | |_2. Its Uses. | _ | 2. THE TASTE...| 1. Description of the Organ. | |_2. Its Uses. | _ | 3. THE SMELL...| 1. Description of the Organ. | |_2. Its Uses. | _ _ | | 1. Description of the | a. _External Ear._ | | Organ...............| b. _Middle Ear._ | 4. THE HEARING.| |_c. _Internal Ear._ | | 2. How we Hear | |_3. Hygiene of the Ear. | _ | | 1. Description of the Organ. | | 2. Eyelids, and Tears. | | 3. Structure of the Retina. |_5. THE SIGHT...| 4. How we see. | 5. The Use of the Crystalline Lens. | 6. Near and Far Sight. | 7. Color Blindness. |_8. Hygiene of the Eyes. THE SPECIAL SENSES 1. TOUCH. DESCRIPTION.--Touch is sometimes called the "common sense," since its nerves are spread over the whole body. It is most delicate, however, in the point of the tongue and the tips of the fingers. The surface of the cutis is covered with minute, conical projections called _papillæ_ (Fig. 24). [Footnote: In the palm of the hand, where there are at least twelve thousand in a square inch, we can see the fine ridges along which they are arranged.] Each one of these papillæ contains its tiny nerve twigs, which receive the impression and transmit it to the brain, where the perception is produced. USES.--Touch is the first of the senses used by a child. By it we obtain our idea of solidity, and throughout life rectify all other sensations. Thus, when we see anything curious, our first desire is to handle it. The sensation of touch is generally relied upon, yet, if we hold a marble in the manner shown in Fig. 57, it will seem like two marbles; and if we touch the fingers thus crossed to our tongue, we shall seem to feel two tongues. Again, if we close our eyes and let another person move one of our fingers over a plane surface, first lightly, then with greater pressure, and then lightly again, we shall think the surface concave. FIG. 57. [Illustration:] This organ is capable of wonderful cultivation. The physician acquires by practice the _tactus eruditus_, or learned touch, which is often of great service, while the delicacy of touch possessed by the blind almost compensates the loss of the absent sense. [Footnote: The sympathy between the different organs shows how they all combine to make a home for the mind. When one sense fails, the others endeavor to remedy the defect. It is touching to see how the blind man gets along without eyes, and the deaf without ears. Cuthbert, though blind, was the most efficient polisher of telescopic mirrors in London. Saunderson, the successor of Newton as professor of mathematics at Cambridge, could distinguish between real and spurious medals. There is an instance recorded of a blind man who could recognize colors. The author knew one who could tell when he was approaching a tree, by what he described as the "different feeling of the air."] (See p. 346.) 2. TASTE. DESCRIPTION.--This sense is located in the papillæ of the tongue and palate. These papillaæ start up when tasting, as you can see by placing a drop of vinegar on another person's tongue, or your own before a mirror. The velvety look of this organ is given by hair-like projections of the cuticle upon some of the papillæ. They absorb the liquid to be tasted, and convey it to the nerves. [Footnote: An insoluble substance is therefore tasteless.] The back of the tongue is most sensitive to salt and bitter substances, and, as this part is supplied by the ninth pair of nerves (Fig. 56), in sympathy with the stomach, such flavors, by sympathy, often produce vomiting. The edges of the tongue are most sensitive to sweet and sour substances, and as this part is supplied by the fifth pair of nerves, which also goes to the face, an acid, by sympathy, distorts the countenance. FIG. 58. [Illustration: _The Tongue, showing the several kinds of Papillæ--the conical_ (D) _the whip like_ (K, I), _the circumvallate or entrenched_ (H, L); E, F, G, _nerves;_ C, _glottis._--LANKESTER.] THE USE OF THE TASTE was originally to guide in the selection of food; but this sense has become so depraved by condiments and the force of habit that it would be a difficult task to tell what are one's natural tastes. 3. SMELL. [Footnote: The sense of smell is so intimately connected with that of taste that we often fail to distinguish between them. Garlic, vanilla, coffee and various spices, which seem to have such distinct taste, have really a powerful odor, but a feeble flavor.] DESCRIPTION.--The nose, the seat of the sense of smell, is composed of cartilage covered with muscles and skin, and joined to the skull by small bones. The nostrils open at the back into the pharynx, and are lined by a continuation of the mucous membrane of the throat. The olfactory nerves (first pair, Fig. 55) enter through a sieve-like, bony plate at the roof of the nose, and are distributed over the inner surface of the two olfactory chambers. (See p. 346.) The object to be smelled need not touch the nose, but tiny particles borne on the air enter the nasal passages. [Footnote: Three quarters of a grain of musk placed in a room will cause a powerful smell for a considerable length of time without any sensible diminution in weight, and the box in which musk has been placed retains the perfume for almost an indefinite period. Haller relates that some papers which had been perfumed by a grain of ambergris, were still very odoriferous after a lapse of forty years. Odors are transported by the air to a considerable distance. A dog recognizes his master's approach by smell even when he is far away; and we are assured by navigators that the winds bring the delicious odors of the balmy forests of Ceylon to a distance of ten leagues from the coast. Even after making due allowance for the effects of the imagination, it is certain that odors act as an excitant on the brain, which may be dangerous when long continued. They are especially dreaded by the Roman women. It is well known that in ancient times the women of Rome indulged in a most immoderate use of baths and perfumes; but those of our times have nothing in common with them in this respect; and the words of a lady are quoted, who said on admiring an artificial rose, "It is all the more beautiful that it has no smell." We are warned by the proverb not to discuss colors or tastes, and we may add odors also. Men and nations differ singularly in this respect. The Laplander and the Esquimaux find the smell of fish oil delicious. Wrangel says his compatriots, the Russians, are very fond of the odor of pickled cabbage, which forms an important part of their food; and asafœtida, it is said, is used as a condiment in Persia, and, in spite of its name, there are persons who do not find its odor disagreeable any more than that of valerian.--_Wonders of the Human body_.] FIG. 59. [Illustration: A, b, c, d, _interior of the nose, which is lined by a mucous membrane;_ n, _the nose;_ e, _the wing of the nose;_ q, _the nose bones;_ o, _the upper lip;_ g, _section of the upper jaw-bone;_ h, _the upper part of the mouth, or hard palate;_ m, _frontal bone of the skull;_ k, _the ganglion or bulb of the olfactory nerve in the skull, from which are seen the branches of the nerve passing in all directions._] THE USES of the sense of smell are to guide us in the choice of our food, and to warn us against bad air, and unhealthy localities. (See p. 348.) 4. HEARING. DESCRIPTION.--The ear is divided into the _external_, _middle_, and _internal_ ear. 1. _The External Ear_ is a sheet of cartilage curiously folded for catching sound. The auditory canal, _B_, or tube of this ear trumpet, is about an inch long. Across the lower end is stretched _the membrane of the tympanum_ or drum, which is kept soft by a fluid wax. FIG. 60. [Illustration: _The Ear._] 2. _The Middle Ear_ is a cavity, at the bottom of which is the Eustachian tube, _G_, leading to the mouth. Across this chamber hangs a chain of three singular little bones, _C_, named from their shape the _hammer_, the _anvil_, and the _stirrup_. All together these tiny bones weigh only a few grains, yet they are covered by a periosteum, are supplied with blood vessels, and they articulate with perfect joints (one a ball-and-socket, the other a hinge), having synovial membranes, cartilages, ligaments, and muscles. 3. _The Internal Ear_, or labyrinth, as it is sometimes called from its complex character, is hollowed out of the solid bone. In front, is the vestibule or antechamber, _A_, about as large as a grain of wheat; from it open three _semicircular canals_, _D_, and the winding stair of the _cochlea_, or snail shell, _E_. Here expand the delicate fibrils of the auditory nerve. Floating in the liquid which fills the labyrinth is a little bag containing hair-like bristles, fine sand, and two ear stones (_otoliths_). All these knocking against the ends of the nerves, serve to increase any impulse given to the liquid in which they lie. Finally, to complete this delicate apparatus, in the cochlea are minute tendrils, named the fibers of Corti, from their discoverer. These are regularly arranged,--the longest at the bottom, and the shortest at the top. Could this spiral plate, which coils two and a half times around, be unrolled and made to stand upright, it would form a beautiful microscopic harp of three thousand strings. If it were possible to strike these cords as one can the keyboard of a piano, he could produce in the mind of the person experimented upon every variety of tone which the ear can distinguish. HOW WE HEAR.--Whenever one body strikes another in the air, waves are produced, just as when we throw a stone into the water a series of concentric circles surrounds the spot where it sinks. These waves of air strike upon the membrane. This vibrates, and sends the motion along the chain of bones in the middle ear to the fluids of the labyrinth. Here bristles, sand, and stones pound away, and the wondrous harp of the cochlea, catching up the pulsations, [Footnote: The original motion is constantly modified by the medium through which it passes. The bristles, otoliths, and Cortian fibers of the ear, and the rods and cones of the eye (p. 239) serve to convert the vibrations into pulsations which act as stimuli of the appropriate nerve. The molecular change thus produced in the nerve fibers is propagated to the brain.--See _Popluar Physics_, p. 182.] carries them to the fibers of the auditory nerve, which conveys them to the brain, and gives to the mind the idea of sound. CARE OF THE EAR.--The delicacy of the ear is such that it needs the greatest care. Cold water should not be allowed to enter the auditory canal. If the wax accumulate, never remove it with a hard instrument, lest the delicate membrane be injured, but with a little warm water, after which turn the head to let the water run out, and wipe the ear dry. The hair around the ears should never be left wet, as it may chill this sensitive organ. If an insect get in the external ear, pour in a little oil to kill it, and then remove with tepid water. The object of the Eustachian tube is to admit air into the ear, and thus equalize the pressure on the membrane. If it become closed by a cold, or if, from any cause, the pressure be made unequal, so as to produce an unpleasant feeling in the ear, relief may often be obtained by grasping the nose and forcibly swallowing. (See p. 350.) 5. SIGHT. FIG. 61. [Illustration: _The Eye._] DESCRIPTION.--The eye is lodged in a bony cavity, protected by the overhanging brow. It is a globe, about an inch in diameter. The ball is covered by three coats--(l) the _sclerotic_, _d_, a tough, horny casing, which gives shape to the eye, the convex, transparent part in front forming a window, the _cornea_, _d_; (2) the _choroid_, _e_, a black lining, to absorb the superfluous light [Footnote: Neither white rabbits nor albinos have this black lining, and hence their sight is confused.] and (3) the _retina_, _b_, a membrane in which expand fibers of the _optic nerve_, _o_. The _crystalline lens_, _a_, brings the rays of light to a focus on the retina. The lens is kept in place by the ciliary processes, _g_, arranged like the rays in the disk of a passion flower. Between the cornea and the crystalline lens is a limpid fluid termed the _aqueous humor_; while the _vitreous humor_--a transparent, jelly-like liquid fills the space (_h_) back of the crystalline lens. The pupil, _k_, is a hole in the colored, muscular curtain, _i_, the _iris_ (rainbow). (See p. 352.) FIG. 62. [Illustration: _The Eyelashes and the Tear Glands._] EYELIDS AND TEARS.--The eyelids are close-fitting shutters to screen the eye. The inner side is lined with a mucous membrane that is exceedingly sensitive, and thus aids in protecting the eye from any irritating substance. The looseness of the skin favors swelling from inflammation or the effusion of blood, as in a "black eye." The eyelashes serve as a kind of sieve to exclude the dust, and, with the lids, to shield against a blinding light. Just within the lashes are oil glands, which lubricate the edges of the lids, and prevent them from adhering to each other. The tear or _lachrymal_ gland, _G_, is an oblong body lodged in the bony wall of the orbit. It empties by several ducts upon the inner surface, at the outer edge of the upper eyelid. Thence the tears, washing the eye, run into the _lachrymal lake_, _D_, a little basin with a rounded border fitted for their reception. On each side of this lake two canals, _C_, _C_, drain off the overplus through the duct, _B_, into the nose. In old age and in disease, these canals fail to conduct the tears away, and hence the lachrymal lake overflows upon the face. FIG. 63. [Illustration: _Structure of the Retina._] STRUCTURE OF THE RETINA.--In Fig. 63 is shown a section of the retina, greatly magnified, since this membrane never exceeds 1/80 an inch in thickness. On the inner surface next to the vitreous humor, is a lining membrane not shown in the cut. Next to the choroid and comprising about 1/4 the entire thickness of the retina, is a multitude of transparent, colorless, microscopic rods, _a_, evenly arranged and packed side by side, like the seeds on the disk of a sunflower. Among them, at regular intervals, are interspersed the cones, _b_. Delicate nerve fibers pass from the ends of the rods and cones, each expanding into a granular body, _c_, thence weaving a mesh, _d_, and again expanding into the granules, _f_. Last is a layer of fine nerve fibers, _g_, and gray, ganglionic cells, _h_, like the gray matter of the brain, whence filaments extend into _i_, the fibers of the optic nerve. (See p. 354.) The layer of rods and cones is to the eye what the bristles, otoliths, and Cortian fibers are to the ear. Indeed, the nerve itself is insensible to light. At the point where it enters the eye, there are no rods and cones, and this is called the _blind spot_. A simple experiment will illustrate the fact. Hold this book directly before the face, and, closing the left eye, look steadily with the right at the left-hand circle in Fig. 64. Move the book back and forth, and a point will be found where the right-hand circle vanishes from sight. At that moment its light falls upon the spot where the rods and cones are lacking. FIG. 64. [Illustration:] HOW WE SEE.--There is believed to be a kind of universal atmosphere, termed _ether_, filling all space. This substance is infinitely more subtle than the air, and occupies its pores, as well as those of all other substances. As sound is caused by waves in the atmosphere, so light is produced by waves in the ether. A lamplight, for example, sets in motion waves of ether, which pass in through the pupil of the eye, to the retina, where the rods and cones transmit the vibration through the optic nerve to the brain, and then the mind perceives the light. (Note, p. 236.) THE USE OF THE CRYSTALLINE LENS. [Footnote: The uses of the eye and ear are dependent upon the principles of Optics and Acoustics. They are therefore best treated in Physics.]--A convex lens, as a common burning glass, bends the rays of light which pass through it, so that they meet at a point called the _focus_. The crystalline lens converges the rays of light which enter the eye, and brings them to a focus on the retina. [Footnote: The cornea and the humors of the eye act in the same manner as the crystalline lens, but not so powerfully.] The healthy lens has a power of changing its convexity so as to adapt [Footnote: The simplest way of experimenting on the "adjustment of the eye" is to stick two stout needles upright into a straight piece of wood,--not exactly, but nearly in the same straight line, so that, on applying the eye to one end of the piece of wood, one needle (A) shall be seen about six inches off, and the other (B) just on one side of it, at twelve inches distance. If the observer looks at the needle B he will find that he sees it very distinctly, and without the least sense of effort; but the image of A is blurred, and more or less double. Now, let him try to make this blurred image of the needle A distinct. He will find he can do so readily enough, but that the act is accompanied by a sense of fatigue. And in proportion as A becomes distinct, B will become blurred. Nor will any effort enable him to see A and B distinctly at the same time.--HUXLEY.] itself to near and to distant objects. (See Fig. 66.) FIG. 65. [Illustration: _Diagram showing how an image of an object is formed upon the Retina by the Crystalline Lens._] NEAR AND FAR SIGHT.--If the lens be too convex, it will bring the rays to a focus before they reach the retina; if too flat, they will reach the retina before coming to a focus. In either case, the sight will be indistinct. A more common defect, however, is in the shape of the globe of the eye, which is either flattened or elongated. In the former case (see _G_, Fig. 67), objects at a distance can be seen most distinctly-- hence that is called farsightedness. [Footnote: This should not be confounded with the long sight of old people, which is caused by the stiffness of the ciliary muscles, whereby the lens can not adapt itself to the varying distances of objects.] In the latter, objects near by are clearer, and hence this is termed nearsightedness. Farsightedness is remedied by convex glasses; nearsightedness, by concave. When glasses will improve the sight they should be worn; [Footnote: Dr. Henry W. Williams, the celebrated ophthalmologist, says that, in some cases, glasses are more necessary at six or eight years of age than to the majority of healthy eyes at sixty. Sometimes children find accidentally that they can see better through grandmother's spectacles. They should then be supplied with their own.] any delay will be liable to injure the eyes, by straining their already impaired power. Cataract is a disease in which there is an opacity of the crystalline lens or its capsules, which obscures the vision. The lens may be caused to be absorbed, or may be removed by a skillful surgeon and the defect remedied by wearing convex glasses. FIG. 66. [Illustration: _Adjustment of the Crystalline Lens._--A, _for far objects, and_ B, _for near._] FIG. 67. [Illustration: _Diagram illustrating the position of the Retina._--B, _in natural sight;_ G, _in far sight; and_ C, _in near sight._] COLOR-BLIND PERSONS receive only two of the three elementary color sensations (green, red, violet). The spectrum appears to them to consist of two decidedly different colors, with a band of neutral tint between. The extreme red end is invisible, and a bright scarlet and a deep green appear alike. They are unable to distinguish between the leaves of a cherry tree and its fruit by the color of the two, and see no difference between blue and yellow cloth. Whittier, the poet, it is said, could not tell red from green unless in direct sunlight. Once he patched some damaged wall paper in his library by matching a green vine in the pattern with one of a bright autumnal crimson. This defect in the eye is often unnoticed, and many railway accidents have doubtless happened through an inability to detect the color of signal lights. CARE OF THE EYES.--The shape of the eye can not be changed by rubbing and pressing it, as many suppose, but the sight may thus be fatally injured. Children troubled by nearsightedness should not lean forward at their work, as thereby the vessels of the eye become overcharged with blood. They should avoid fine print, and try, in every possible way, to spare their eyes. If middle age be reached without especial difficulty of sight, the person is comparatively safe. Most cases of squinting are caused by longsightedness, the muscles being strained in the effort to obtain distinct vision. In childhood, it may be cured by a competent surgeon, who will generally cut the muscle that draws the eye out of place. After any severe illness, especially after measles, scarlatina, or typhoid fever, the eyes should be used with extreme caution, since they share in the general debility of the body, and recover their strength slowly. Healthy eyes even should never be used to read fine print or by a dim light. Serious injury may be caused by an imprudence of this kind. Reading upon the cars is also a fruitful source of harm. The lens, striving to adapt itself to the incessantly varying distance of the page, soon becomes wearied. Whenever the eyes begin to ache, it is a warning that they are being overtaxed and need rest. Objects that get into the eye should be removed before they cause inflammation; rubbing in the meantime only irritates and increases the sensitiveness. If the eye be shut for a few moments, so as to let the tears accumulate, and the upper lid be then lifted by taking hold of it at the center, the cinder or dust is often washed away at once. Trifling objects can be removed by simply drawing the upper lid as far as possible over the lower one; when the lid flies back to its place, the friction will detach any light substance. If it becomes necessary, turn the upper lid over a pencil, and the intruder may then be wiped off with a handkerchief. "Eye-stones" are a popular delusion. When they seem to take out a cinder, it is only because they raise the eyelid, and allow the tears to wash it out. No one should ever use an eyewash, except by medical advice. The eye is too delicate an organ to be trifled with, and when any disease is suspected, a reliable physician should be consulted. This is especially necessary, since, when one eye is injured, the other, by sympathy, is liable to become inflamed, and perhaps be destroyed. When reading or working, the _light should be at the left side, or at the rear; never in front_. The constant increase of defective eyesight among the pupils in our schools is an alarming fact. Dr. Agnew considers that our schoolrooms are fast making us a spectacle-using people. Nearsightedness seems to increase from class to class, until in the upper departments, there are sometimes as high as fifty per cent of the pupils thus afflicted. The causes are (1), desks so placed as to make the light from the windows shine directly into the eyes of the scholars; (2), cross lights from opposite windows; (3), insufficient light; (4), small type that strains the eyes; and (5), the position of the pupil as he bends over his desk or slate, causing the blood to settle in his eyes. All these causes can be remedied; the position of the desks can be changed; windows can be shaded, or new ones inserted; books and newspapers that try the eyes can be rejected; and every pupil can be taught how to sit at study. PRACTICAL QUESTIONS. 1. Why does a laundress test the temperature of her flatiron by holding it near her cheek? 2. When we are cold, why do we spread the palms of our hands before the fire? 3. What is meant by a "furred tongue"? 4. Why has sand or sulphur no taste? 5. What was the origin of the word palatable? 6. Why does a cold in the head injure the flavor of our coffee? 7. Name some so-called flavors that are really sensations of touch. 8. What is the object of the hairs in the nostrils? 9. What use does the nose subserve in the process of respiration? 10. Why do we sometimes hold the nose when we take unpleasant medicine? 11. Why was the nose placed over the mouth? 12. Describe how the hand is adapted to be the instrument of touch. 13. Besides being the organ of taste, what use does the tongue subserve? 14. Why is not the act of tasting complete until we swallow? 15. Why do all things have the same flavor when one's tongue is "furred" by fever? 16. Which sense is the more useful--hearing or sight? 17. Which coat is the white of the eye? 18. What makes the difference in the color of eyes? 19. Why do we snuff the air when we wish to obtain a distinct smell? 20. Why do red-hot iron and frozen mercury (-40°) produce the same sensation? 21. Why can an elderly person drink tea which to a child would be unbearably hot? 22. Why does an old man hold his paper so far from his eyes? 23. Would you rather be punished on the tips of your fingers than on the palm of your hand? 24. What is the object of the eyelashes? Are the hairs straight? 25. What is the use of winking? 26. When you wink, do the eyelids touch at once along their whole length? Why? 27. How many rows of hairs are there in the eyelashes? 28. Do all nations have eyes of the same shape? 29. Why does snuff taking cause a flow of tears? 30. Why does a fall cause one to "see stars"? 31. Why can we not see with the nose, or smell with the eyes? 32. What causes the roughness of a cat's tongue? 33. Is the cuticle essential to touch? 34. Can one tickle himself? 35. Why does a bitter taste often produce vomiting? 36. Is there any danger in looking "crosseyed" for fun? 37. Should schoolroom desks face a window? 38. Why do we look at a person to whom we are listening attentively? 39. Do we really feel with our fingers? 40. Is the eye a perfect sphere? (See Fig. 61.) 41. How often do we wink? 42. Why is the interior of a telescope or microscope often painted black? 43. What is "the apple of the eye"? 44. What form of glasses do old people require? 45. Should we ever wash our ears with cold water? 46. What is the object of the winding passages in the nose? 47. Can a smoker tell in the dark, whether or not his cigar is lighted? 48. Will a nerve reunite after it has been cut? 49. Will the sight give us an idea of solidity? [Footnote: A case occurred a few years ago, in London, where a friend of my own performed an operation upon a young woman who had been born blind, and, though an attempt had been made in early years to cure her, it had failed. She was able just to distinguish large objects, the general shadow, as it were, without any distinct perception of form, and to distinguish light from darkness. She could work well with her needle by the touch, and could use her scissors and bodkin and other implements by the training of her hand, so to speak, alone Well, my friend happened to see her, and he examined her eyes, and told her that he thought he could get her sight restored; at any rate, it was worth a trial. The operation succeeded; and, being a man of intelligence and quite aware of the interest of such a case, he carefully studied and observed it; and he completely confirmed all that had been previously laid down by the experience of similar cases. There was one little incident which will give you an idea of the education which is required for what you would suppose is a thing perfectly simple and obvious. She could not distinguish by sight the things that she was perfectly familiar with by the touch, at least when they were first presented to her eyes. She could not recognize even a pair of scissors. Now, you would have supposed that a pair of scissors, of all things in the world, having been continually used by her, and their form having become perfectly familiar to her hands, would have been most readily recognized by her sight; and yet she did not know what they were; she had not an idea until she was told, and then she laughed, as she said, at her own stupidity. No stupidity at all; she had never learned it, and it was one of those things which she could not know without learning. One of the earliest cases of this kind was related by the celebrated Cheselden, a surgeon of the early part of last century. Cheselden relates how a youth just in this condition had been accustomed to play with a cat and a dog; but for some time after he attained his sight he never could tell which was which, and used to be continually making mistakes. One day, being rather ashamed of himself for having called the cat the dog, he took up the cat in his arms and looked at her very attentively for some time stroking her all the while; and in this way he associated the impression derived from the touch, and made himself master (so to speak) of the whole idea of the animal. He then put the cat down, saying: "Now, puss, I shall know you another time."--CARPENTER.] 50. Why can a skillful surgeon determinate the condition of the brain and other internal organs by examining the interior of the eye? [Footnote: This is done by means of an instrument called the ophthalmoscope. Light is thrown into the eye with a concave mirror, and the interior of the organ examined with a lens.] 51. Is there any truth in the idea that the image of the murderer can be seen in the eye of the dead victim? 52. What is the length of the optic nerve? _Ans_. About three fourths of an inch. 53. Why does an injury to one eye generally affect the other eye? _Ans_. The optic nerves give off no branches in passing from their origin in two ganglia situated between the cerebrum and the cerebellum, and their termination in the eyeballs; but, in the middle of their course, they _decussate_, or unite in one mass. The fibers of the two nerves here pass from side to side, and intermingle. The two ganglia are also united directly by fibers. Thus the eyes are not really separate organs of sight, but a kind of double organ to perform, a single function. IX. HEALTH AND DISEASE.--DEATH AND DECAY. "Health is the vital principle of bliss." THOMSON. "There are three wicks to the lamp of a man's life: brain, blood, and breath. Press the brain a little, its light goes out, followed by both the others. Stop the heart a minute, and out go all three of the wicks. Choke the air out of the lungs, and presently the fluid ceases to supply the other centers of flame, and all is soon stagnation, cold, and darkness." O. W. HOLMES. "Calmly he looked on either Life, and here Saw nothing to regret, or there to fear; From Nature's temp'rate feast rose satisfy'd, Thank'd Heaven that he had lived, and that he died." POPE. HEALTH AND DISEASE.--DEATH AND DECAY. VALUE OF HEALTH.--The body is the instrument which the mind uses. If it be dulled or nicked, the effect of the best labor will be impaired. The grandest gifts of mind or fortune are comparatively valueless unless there be a healthy body to use and enjoy them. The beggar, sturdy and brave with his outdoor life, is really happier than the rich man in his palace with the gout to twinge him amid his pleasures. The day has gone by when delicacy is considered an element of beauty. Weakness is timid and irresolute; strength is full of force and energy. Weakness walks or creeps; strength speeds the race, wins the goal, and rejoices in the victory. FALSE IDEAS OF DISEASE.--It was formerly supposed that diseases were caused by evil spirits, who entered the body, and deranged its action. Incantations, spells, etc., were resorted to in order to drive them out. By others, disease was thought to come arbitrarily, or as a special visitation of an overruling power. Hence, it was to be removed by fasting and prayer. Modern science teaches us that disease is not a thing, but a state. When our food is properly assimilated, the waste matter promptly excreted, and all the organs work in harmony, we are well; when any derangement of these functions occurs, we are sick. Sickness is discord, as health is concord. If we abuse or misuse any instrument, we impair its ability to produce a perfect harmony. A suffering body is simply the penalty of violated law. PREVENTION OF DISEASE.--Doubtless a large proportion of the ills which now afflict and rob us of so much time and pleasure might easily be avoided. A proper knowledge and observance of hygienic laws would greatly lessen the number of such diseases as consumption, catarrh, gout, rheumatism, dyspepsia, etc. There are parts of England where one half the children die before they are five years old. Every physiologist knows that at least nine tenths of these lives could be saved by an observance of the simple laws of health. Professor Bennet, in a lecture at Edinburgh, estimated that one hundred thousand persons die annually in Great Britain from causes easily preventable. With the advance of science, the causes of many diseases have been determined. Vaccination has been found to prevent or mitigate the ravages of smallpox. Scurvy, formerly so fatal among sailors that it was deemed "a mysterious infliction of Divine Justice against which man strives in vain," is now entirely avoided by the use of vegetables or lime juice. Cholera, whose approach still strikes dread, and for which there is no known specific, is but the penalty for filthy streets, bad drainage, and overcrowded tenements, and may be controlled, if not prevented, by suitable sanitary measures. It was, no doubt, the intention that we should wear out by the general decay of all the organs, [Footnote: So long as the phenomena of waste and repair are in harmony--so long, in other words, as the builder follows the scavenger--so long man exists in integrity and repair--just, indeed, as houses exist. Derange nutrition, and at once degeneration, or rather let us say, alteration begins. Alas! that we are so ignorant that there are many things about our house, which, seeing them, weaken, we know not how to strengthen. About the brick and the mortar, the frame and the rafters, we are not unlearned; but within are many complexities, many chinks and crannies, full in themselves of secondary chinks and crannies, and these so small, so deep, so recessed, that it happens every day that the destroyer settles himself in some place so obscure, that, while he kills, he laughs at defiance. You or I meet with an accident in our watch. We consult the watchmaker, and he repairs the injury. If we were all that watchmakers, like ourselves, should be, a man could be made to keep time until he died from old age or annihilating accident. This I firmly and fully believe.--_Odd Hours of a Physician_.] rather than by the giving out of any single part, and that all should work together harmoniously until the vital force is exhausted. CURE OF DISEASE.--The first step in the cure of any disease is to obey the law of health which has been violated. If medicine be taken, it is not to destroy the disease, since that is not a thing to be destroyed, but to hold the deranged action in check while nature repairs the injury, and again brings the system into harmonious movement. This tendency of nature is our chief reliance. The best physicians are coming to have diminished confidence in medicine itself, and to place greater dependence upon sanitary and hygienic measures, and upon the efforts which nature always makes to repair injuries and soothe disordered action. They endeavor only to give to nature a fair chance, and sometimes to assist her by the intelligent employment of proper medicines. The indiscriminate use of patent nostrums and sovereign remedies of whose constituents we know nothing, and by which powerful drugs are imbibed at haphazard, can not be too greatly deprecated. When one needs medicine, he needs also a competent physician to advise its use. DEATH AND DECAY.--By a mystery we can not understand, life is linked with death, and out of the decay of our bodies they, day by day, spring afresh. At last the vital force which has held death and decay in bondage, and compelled them to minister to our growth, and to serve the needs of our life, faints and yields the struggle. These powers which have so long time been our servants, gather about our dying couch, and their last offices usher us into the new life and the grander possibilities of the world to come. This last birth, we who see the fading, not the dawning, life, call death. "O Father! grant Thy love divine, To make these mystic temples Thine, When wasting age and wearying strife Have sapp'd the leaning walls of life; When darkness gathers over all, And the last tottering pillars fall, Take the poor dust Thy mercy warms, And mold it into heavenly forms." HOLMES. HINTS ABOUT THE SICK ROOM A SICK ROOM should be the lightest and cheeriest in the house. A small, close, dark bedroom or a recess is bad enough for one in health, but unendurable for a sick person. In a case of fever, and in many acute diseases, it should be remote from the noise of the family; but when one is recovering from an accident, and in all attacks where quiet is not needed, the patient may be where he can amuse himself by watching the movements of the household, or looking out upon the street. _The ventilation must be thorough._ Bad air will poison both the sick and the well. A fireplace is, therefore, desirable. Windows should open easily. By carefully protecting the patient with extra blankets, the room may be frequently aired. If there be no direct draught, much may be done to change the air, by simply swinging an outer door to and fro many times. A bare floor, with strips of carpet here and there to deaden noise, is cleanest, and keeps the air freest from dust. Cane-bottomed chairs are preferable to upholstered ones. All unnecessary furniture should be removed out of the way. A straw bed or a mattress is better than feathers. The bed hangings, lace curtains, etc., should be taken down. Creaking hinges should be oiled. Sperm candles are better than kerosene lamps. _Never whisper in a sick room._ All necessary conversation should be carried on in the usual tone of voice. Do not call a physician unnecessarily, but if one be employed, _obey his directions implicitly_. Never give nostrums overofficious friends may suggest. Do not allow visitors to see the patient, except it be necessary. Never bustle about the room, nor go on tiptoe, but move in a quiet, ordinary way. Do not keep the bottles in the continued sight of the sick person. Never let drinking water stand in the room. Do not raise the patient's head to drink, but have a cup with a long spout, or use a bent tube, or even a straw. Do not tempt the appetite when it craves no food. Bathe frequently, but let the physician prescribe the method. Give written directions to the watchers. Have all medicines carefully marked. Remove all soiled clothing, etc., at once from the room. Change the linen much oftener than in health. When you wish to change the sheets, and the patient is unable to rise, roll the under sheet tightly lengthwise to the middle of the bed; put on the clean sheet, with half its width folded up, closely to the other roll; lift the patient on to the newly-made part, remove the soiled sheet, and then spread oat the clean one. DISINFECTANTS. Remember, first, that deodorizers and disinfectants are not the same. A bad smell, for instance, may be smothered by some more powerful odor, while its cause remains uninfluenced. Bear also in mind the fact that no deodorizer and no disinfectant can take the place of perfect cleanliness and thorough ventilation. No purifyer can rival the oxygen contained in strong and continued currents of fresh, cold air, and every disinfectant finds an indispensable ally in floods of scalding water. An excellent disinfectant may be made by dissolving in a pail of water either of the following: (1), a quarter of a pound of sulphate of zinc and two ounces of common salt for each gallon of water; (2), a pound and a half of copperas, for each gallon of water. Towels, bed linen, handkerchiefs, etc., should be soaked at least an hour, in a solution of the first kind, and then be boiled, before washing. [Footnote: It is _best_ to burn all articles which have been in contact with persons sick with contagious or infectious diseases. In using the zinc solution, place the articles in it as soon as they are removed from the patient, and before they are taken from the room; if practicable, have the solution boiling hot at the time. In fumigating apartments, all the openings should be made as nearly air-tight as possible. The articles to be included in the fumigation should be so exposed and spread out that the sulphurous vapor may penetrate every portion of them. For a room about ten feet square, at least two pounds of sulphur should be used; for larger rooms, proportionally increased quantities. Put the sulphur in iron pans supported upon bricks placed in washtubs containing a little water, set it on fire by hot coals or with the aid of a spoonful of alcohol, or by a long fuse set on train as the last opening to the room is closed. Allow the apartment to remain sealed for twenty-four hours. Great care should be taken not to inhale the poisonous fumes in firing the sulphur. After the fumigation, allow free currents of air to pass through the apartment; expose all movable articles for as long time as may be to the sun and the wind out of doors; beat and shake the carpets, hangings, pillows, etc. The disinfectants and the instructions for using them, as given above, are mainly those recommended by the National Board of Health.] Vaults, drains, vessels used in the sick room, etc., should be disinfected by a solution of the second kind; chloride of lime may also be used for the same purpose. Rooms, furniture, and articles that can not be treated with the solution of the first kind, should be thoroughly fumigated with burning sulphur. Where walls are unpapered, re-whitewash with pure, freshly slacked quicklime, adding one pint of the best fluid carbolic acid to every gallon of the fluid whitewash. Powdered stone lime sprinkled on foul, wet places, or placed in pans in damp rooms, will absorb the moisture; and dry, fresh charcoal powder may be combined with it to absorb noxious gases. WHAT TO DO TILL THE DOCTOR COMES. The following instructions are intended simply to aid in an emergency. When accidents or a sudden severe illness occur, there is necessarily, in most cases, a longer or shorter interval before a physician can arrive. These moments are often very precious, and life may depend upon a little knowledge and much self-possession. The instructions are therefore given as briefly as possible, that they may be easily carried in the memory. A few suggestions in regard to common ailments are included. BURNS.--When a person's clothes catch fire, quickly lay him on the ground, wrap him in a coat, mat, shawl, carpet, or in his own garments, as best you can to extinguish the flame. Pour on plenty of water till the half- burned clothing is cooled. Then carry the sufferer to a warm room, lay him on a table or a carpeted floor, and with a sharp knife or scissors remove his clothing. The treatment of a burn consists in protecting from the air. [Footnote: It is a great mistake to suppose that salves will "draw out the fire" of a burn, or heal a bruise or cut. The vital force must unite the divided tissue by the deposit of material and the formation of new cells.] An excellent remedy is to apply soft cloths kept wet with sweet oil, or with tepid water _which contains all the "cooking soda" that it will dissolve_. Afterward dress the wound with carbolic acid salve. Wrap a dry bandage upon the outside. Then remove the patient to a bed and cover warmly. [Footnote: In case of a large burn, lose no delay in bringing a physician. If a burn be near a joint or on the face, even if small, let a doctor see it, and do not be in any hurry about having it healed. Remember that with all the care and skill which can be used, contractions will sometimes take place. The danger to life from a burn or scald is not in proportion to its severity, but to its extent--that is, a small part, such as a hand or a foot, may be burned so deeply as to cripple it for life, and yet not much endanger the general health; but a slight amount of burning, a mere scorching, over two thirds of the body, may prove fatal.-- HOPE.] Apply cool water to a small burn till the smart ceases, and then cover with ointment. Do not remove the dressings until they become stiff and irritating; then take them from a part at a time; dress and cover again quickly. CUTS, WOUNDS, ETC.--The method of stopping the bleeding has been described on page 128. If an artery is severed, a physician should be called at once. If the bleeding is not profuse, apply cold water until it ceases, dry the skin, draw the edges of the wound together, and secure them by strips of adhesive plaster. Protect with an outer bandage. This dressing should remain for several days. In the meantime wet it frequently with cool water to subdue inflammation. When suppuration begins, wash occasionally with tepid water and Castile soap. Dr. Woodbridge, of New York, in a recent address, gave the following directions as to "What to do in case of a sudden wound when the surgeon is not at hand." "An experienced person would naturally close the lips of the wound as quickly as possible, and apply a bandage. If the wound is bleeding freely, but no artery is spouting blood, the first thing to be done is to wash it with water at an ordinary temperature. To every pint of water add either five grains of corrosive sublimate, or two and a half teaspoonfuls of carbolic acid. If the acid is used, add two tablespoonfuls of glycerine, to prevent its irritating the wound. If there is neither of these articles in the house, add four tablespoonfuls of borax to the water. Wash the wound, close it, and apply a compress of a folded square of cotton or linen. Wet it in the solution used for washing the wound and bandage quickly and firmly. If the bleeding is profuse, a sponge dipped in very hot water and wrung out in a dry cloth should be applied as quickly as possible. If this is not available, use ice, or cloths wrung out in ice water. If a large vein or artery is spouting, it must be stopped at once by compression. This may be done by a rubber tube wound around the arm tightly above the elbow or above the knee, where the pulse is felt to beat; or an improvised 'tourniquet' may be used. A hard apple or a stone is placed in a folded handkerchief, and rolled firmly in place. This bandage is applied so that the hard object rests on the point where the artery beats, and is then tied loosely around the arm. A stick is thrust through the loose bandage and turned till the flow of blood ceases." BLEEDING FROM THE NOSE is rarely dangerous, and often beneficial. When it becomes necessary to stop it, sit upright and compress the nostrils between the thumb and forefinger, or with the thumb press upward upon the upper lip. A piece of ice, a snowball, or a compress wet with cold water may be applied to the back of the neck. A SPRAIN [Footnote: "A sprain," says Dr. Hope, in that admirable little book entitled _Till the Doctor comes and How to help Him_, "is a very painful and very serious thing. When you consider that from the tips of the fingers to the wrist, or from the ends of the toes to the leg, there are not less than thirty separate bones, all tied together with straps, cords, and elastic bands, and about twenty hinges, all to be kept in good working order, you will not wonder at sprains being frequent and sometimes serious."] is often more painful and dangerous than a dislocation. Wrap the injured part in flannels wrung out of hot water, and cover with a dry bandage, or, better, with oiled silk. Liniments and stimulating applications are injurious in the first stages, but useful when the inflammation is subdued. _Do not let the limb hang down, keep the joint still_. Without attention to these points, no remedies are likely to be of much service. A sprained limb must be kept quiet, even after all pain has ceased. If used too soon, dangerous consequences may ensue. Many instances have been known in which, from premature use of an injured limb, the inflammation has been renewed and made chronic, the bones at the joint have become permanently diseased, and amputation has been necessitated. DIARRHEA, CHOLERA MORBUS, ETC., are often caused by eating indigestible or tainted food, such as unripe or decaying fruit, or stale vegetables; or by drinking impure water or poisoned milk (see p. 321). Sometimes the disturbance may be traced to a checking of the perspiration; but more frequently to peculiar conditions of the atmosphere, especially in large cities. Such diseases are most prevalent in humid weather, when the days are hot and the nights cold and moist. Especial attention should at such times be paid to the diet. If an attack comes on, ascertain, if possible, its cause. You can thereby aid your physician, and, if the cause be removable, can protect the rest of the household. If the limbs are cold, take a hot bath, followed by a thorough rubbing. Then go to bed and lie quietly on the back. In ordinary cases, rest is better than medicine. If there be pain, have flannels wrung out of hot water applied to the abdomen. [Footnote: If it be difficult to manage the foments, lay a hot plate over the flannels and cover with some protection. By having a change of hot plates, the foments can be kept at a uniform high temperature. This plan will be found useful in all cases where foments are needed.] A mustard poultice will serve the same purpose if more convenient. Eat no fruit, vegetables, pastry, or pork. Use water sparingly. If much thirst exist, give small pieces of ice, or limited quantities of cold tea or toast water. Take particular pains with the diet for some days after the bowel irritation has ceased. CROUP.--There are two kinds of croup--true and false. True croup comes on gradually, and is less likely to excite alarm than false croup, which comes on suddenly. True croup is attended with fever and false membrane in the throat; false croup is not attended with fever or false membrane. True croup is almost always fatal in four or five days; false croup recovers, but is liable to come on again. The great majority of cases of the so- called croup are simply cases of spasm of the glottis. "Croupy children" are those who are liable to these attacks of false croup, which are most frequent during the period of teething.--DR. GEO. M. BEARD. Croup occurs commonly in children between the ages of two and seven years. At this period, if a child has a hollow cough, with more or less fever, flushed face, red watery eyes, and especially _if it have a hoarse voice, and show signs of uneasiness about the throat_, send at once for a doctor. Induce mild vomiting by doses of syrup of ipecac. Put the feet in a hot mustard-and-water bath. Apply hot fomentations, rapidly renewed, to the chest and throat. A "croupy" child should be carefully shielded from all physical excitation, sudden waking from sleep, and any punishment that tends to awaken intense fear or terror. Irritation of the air passages through faulty swallowing in drinking hastily, should be guarded against. Good pure air, warm clothing, and a nourishing diet are indispensable. COMMON SORE THROAT.--Wrap the neck in a wet bandage, and cover with flannel or a clean woolen stocking. Gargle the throat frequently with a solution of a teaspoonful of salt in a pint of water, or thirty grains of chlorate of potash in a wineglass of water. FITS, APOPLEXY, EPILEPSY, ETC.--These call for immediate action and prompt medical attendance. Children who are teething, or troubled with intestinal worms, or from various causes, are sometimes suddenly seized with convulsions. Apply cloths wet in cold water--or, better still, ice wrapped in oiled silk--to the head, and _especially to the back of the neck_, taking care, however, that the ice or wet cloths do not remain too long. Apply mustard plasters to the stomach and legs. A full hot bath is excellent if the cold applications fail. Endeavor to induce vomiting. Seek to determine the cause, and consult with your physician for further guidance. Apoplexy may be distinguished from a fainting fit by the red face, hot skin, and labored breathing; whereas, in a faint, the face and lips lose color, and the skin becomes cold. In many cases, death follows so quickly upon an apoplectic seizure, that little effectual service can be given. Call the nearest physician, loosen the clothing, and raise the head and shoulders, taking care not to bend the head forward on the neck. Keep the head cool. Do not move the patient unnecessarily. In a common fainting fit, give the patient as much air as possible. Lay him flat upon the floor or ground, and keep the crowd away. All that can be done in a fit of epilepsy is to prevent the patient from injuring himself; especially put something in his mouth to keep him from biting his tongue. A cork, a piece of India rubber, or even a tightly- rolled handkerchief, placed between the teeth will answer this purpose. Give the sufferer fresh air; loosen his clothing, and place him in a comfortable position. Epilepsy may be due to various causes,--improper diet, overexcitement, etc. Consult with a physician, and study to avoid the occasion. CONCUSSION OF THE BRAIN generally arises from some contusion of the head, from violent blows, or from a shock received by the whole body in consequence of falling from a height. In any case of injury to the head where insensibility ensues, a doctor should be called at once. Remove the patient to a quiet room; loosen his clothing; strive to restore circulation by gentle friction, using the hand or a cloth for this purpose; apply cold water to the head, and, if the patient's body be cold and his skin clammy, put hot bottles at his feet. Ammonia may be cautiously held to the nose. Beyond this, it is not safe for a non- professional to go, in case of a severe injury to the head. Concussion is more or less serious, according to the injury which the brain has sustained; but even in slight cases, when a temporary dizziness appears to be the only result, careful treatment should be observed both at the time of the injury and afterward. Cases of head injury are often more grave in their consequences than in their immediate symptoms. Sometimes the patient appears to be getting better when really he is worse. Rest and quiet should be observed for several weeks after an accident which has in any way affected the brain. TOOTHACHE AND EARACHE.--Insert in the hollow tooth cotton wet with laudanum, spirits of camphor, or chloroform. When the nerve is exposed, wet it with creosote or carbolic acid. Hot cloths or a hot brick wrapped in cloth and held to the face will often relieve the toothache. In a similar manner treat the ear, wetting the cloth in hot water, and letting the vapor pass into the ear. CHOKING.--Ordinarily a smart blow between the shoulders, causing a compression of the chest and a sudden expulsion of the air from the lungs, will throw out the offending substance. If the person can swallow, and the object be small, give plenty of bread or potato, and water to wash it down. Press upon the tongue with a spoon, when, perhaps, you may see the object, and draw it out with your thumb and finger, or a blunt pair of scissors. If neither of these remedies avail, give an emetic of syrup of ipecac or mustard and warm water. FROSTBITES are frequently so sudden that one is not aware when they occur. In Canada it is not uncommon for persons meeting in the street to say, "Mind, sir, your nose looks whitish." The blood cools and runs slowly, and the blood vessels become choked and swollen. _Keep from the heat_. Rub the part quickly with snow, if necessary for hours, till the natural color is restored. If one is benumbed with cold, take him into a cold room, remove the wet clothes, rub the body dry, cover with blankets, and give a little warm tea or other suitable drink. On recovering, let him be brought to a fire gradually. [Footnote: If you are caught in a snowstorm, look for a snow bank in the lee of a hill, or a wood out of the wind, or a hollow in the plain filled with snow. Scrape out a hole big enough to creep into, and the drifting snow will keep you warm. Men and animals have been preserved after days of such imprisonment. Remember that if you give way to sleep in the open field, you will never awake.] FEVERS, and many acute diseases, are often preceded by a loss of appetite, headache, shivering, "pains in the bones," indisposition to work, etc. In such cases, sponge with tepid water, and rub the body till all aglow. Go to bed, place hot bricks to the feet, take nothing but a little gruel or beef tea, and drink moderately of warm, cream-of-tartar water. If you do not feel better the next morning, call a physician. If that be impossible, take a dose of castor oil or Epsom salts. SUNSTROKE is a sudden prostration caused by intense heat. The same effect is produced by the burning rays of the sun and the fierce fire of a furnace. When a person falls under such circumstance, place your hand on his chest. If the skin be cool and moist, it is not a sunstroke; but if it be dry and "biting hot," there can be no mistake. Time is now precious. At once carry the sufferer to the nearest pump or hydrant, and dash cold water on the head and chest until consciousness is restored.--DR. H. C. WOOD. To prevent sunstroke, wear a porous hat, and in the top of it place a wet handkerchief; also drink freely of water, not ice cold, to induce abundant perspiration. ASPHYXIA, or apparent death, whether produced by drowning, suffocation, bad air, or coal gas, requires very similar treatment. Send immediately for blankets, dry clothing, and a physician. Treat upon the spot, if the weather be not too unfavorable. 1. Loosen the clothing about the neck and chest, separate the jaws, and place between them a cork or bit of wood. 2. Turn the patient on his face, place his arm under his forehead to raise the head, and press heavily with both hands upon the ribs to squeeze out the water. 3. Place the patient on his back, wipe out the mouth and nostrils, and secure the tongue from falling backward over the throat. Kneel at his head, grasp his arms firmly above the elbows, and pull them gently upward until they meet over the head, in order to draw air into the lungs; reverse this movement to expel the air. Repeat the process about fifteen times per minute. Alternate pressure upon the chest, and blowing air into the mouth through a quill or with a pair of bellows, may aid your efforts. Use snuff or smelling salts, or pass hartshorn under the nose. Do not lose hope quickly. Life has been restored after five hours of suspended animation. [Footnote: Another simple method of artificial respiration is described in the _British Medical Journal_. The body of the patient is laid on the back, with clothes loosened, and the mouth and nose wiped; two bystanders pass their right hands under the body at the level of the waist, and grasp each other's hand, then raise the body until the tips of the fingers and the toes of the subject alone touch the ground; count fifteen rapidly; then lower the body flat to the ground, and press the elbows to the side hard; count fifteen again; then raise the body again for the same length of time; and so on, alternately raising and lowering. The head, arms, and legs are to be allowed to dangle down freely when the body is raised.] 4. When respiration is established, wrap the patient in dry, warm clothes, and rub the limbs under the blankets or over the dry clothing energetically _toward the heart_. Apply heated flannels, bottles of hot water, etc., to the limbs, and mustard plasters [Footnote: The best mustard poultice is the paper plaster now sold by every druggist. It is always ready, and can be carried by a traveler. It has only to be dipped in water, and applied at once.] to the chest. FOREIGN BODIES IN THE EAR.--Insects may be killed by dropping a little sweet oil into the ear. Beans peas, etc., may generally be removed by so holding the head that the affected ear will be toward the ground, and then _cautiously_ syringing tepid water into it from below. Do not use much force lest the tympanum be injured. If this fail, dry the ear, stick the end of a little linen swab into thick glue, let the patient lie on one side, put this into the ear until it touches the substance, keep it there three quarters of an hour while it hardens, and then draw them all out together. Be careful that the glue does not touch the skin at any point, and that you are at work upon the right ear. Children often deceive one as to the ear which is affected. FOREIGN BODIES IN THE NOSE, such as beans, cherry pits, etc., may frequently be removed by closing the opposite nostril, and then blowing into the child's mouth forcibly. The air, unable to escape except through the affected nostril, will sweep the obstruction before it. ANTIDOTES TO POISONS. ACIDS: _Nitric_ (aqua fortis), _hydrochloric_ (muriatic), _sulphuric_ (oil of vitriol), _oxalic_, etc.--Drink a little water to weaken the acid, or, still better, take strong soapsuds. Stir some magnesia in water, and drink freely. If the magnesia be not at hand, use chalk, soda, lime, whiting, soap, or even knock a piece of plaster from the wall, and scraping off the white outside coat pound it fine, mix with milk or water, and drink at once. Follow with warm water, or flaxseed tea. ALKALIES: _Potash, soda, lye, ammonia_ (hartshorn).--Drink weak vinegar or lemon juice. Follow with castor or linseed oil, or thick cream. ANTIMONY: _Antimonial wine, tartar emetic_, etc.--Drink strong, green tea, and in the meantime chew the dry leaves. The direct antidote is a solution of nutgall or oak bark. ARSENIC: _Cobalt, Scheele's green, fly powder, ratsbane_, etc.--Give _plenty of milk, whites of eggs_, or induce vomiting by mustard and warm water; [Footnote: See that the mustard is well mixed with the water, in the proportion of about half an ounce of the former to a pint of the latter.] or even soapsuds. BITE OF A SNAKE OR A MAD DOG.--Tie a bandage above the wound, if on a limb. Wash the bite thoroughly, and, if possible, let the person suck it strongly. Rub some lunar caustic or potash in the wound, or heat the point of a small poker or a steel sharpener white hot, and press it into the bite for a moment. It will scarcely cause pain, and will be effectual in arresting the absorption of the poison, unless a vein has been struck. COPPER: _Sulphate of copper_ (blue vitriol), _acetate of copper_ (verdigris).--Take whites of eggs or soda. Use milk freely. LAUDANUM: _Opium, paregoric, soothing cordial, soothing syrup_, etc. --Give an emetic at once of syrup of ipecac, or mustard and warm water, etc. After vomiting, use strong coffee freely. _Keep the patient awake_ by pinching, pulling the hair, walking about, dashing water in the face, and any expedient possible. LEAD: _White lead, acetate of lead_ (sugar of lead), _red lead_.--Give an emetic of syrup of ipecac, or mustard and warm water, or salt and water. Follow with a dose of Epsom salts. MATCHES: _Phosphorus_.--Give magnesia, chalk, whiting, or even flour in water, and follow with mucilaginous drinks. MERCURY: _Calomel, chloride of mercury_ (corrosive sublimate, bug poison), _red precipitate_.--Drink milk copiously. Take the whites of eggs, or stir flour in water, and use freely. NITRATE OF SILVER (lunar caustic).--Give salt and water, and follow with castor oil. NITRATE OF POTASH (saltpeter, niter).--Give mustard and warm water, or syrup of ipecac. Follow with flour and water, and cream or sweet oil. PRUSSIC ACID (oil of bitter almonds), _cyanide of potassium_.--Take a teaspoonful of hartshorn in a pint of water. Apply smelling salts to the nose, and dash cold water in the face. STING OF AN INSECT.--Apply a little hartshorn or spirits of camphor, or soda moistened with water, or a paste of clean earth and saliva. SULPHATE OF IRON (green vitriol).--Give syrup of ipecac, or mustard and warm water, or any convenient emetic; then magnesia and water. X. SELECTED READINGS TO ILLUSTRATE AND SUPPLEMENT THE TEXT. _Arranged in order of the subjects to which they refer_. "Read not to contradict and confute, nor to believe and take for granted, nor to find talk and discourse, but to weigh, and consider." LORD BACON. "He who learns the rules of wisdom without conforming to them in his life, is like a man who labored in his fields but did not sow." SAADI. SELECTED READINGS. _The figures indicate the pages in the text upon which the corresponding subjects will be found_. THE SKELETON. MAN, AS COMPARED WITH OTHER VERTEBRATE ANIMALS (p. 3).--Man, the lord of the animal kingdom, is constructed after the same type as the cat that purrs at his feet, the ox that he eats, the horse that bears his burden, the bird that sings in his cage, the snake that crawls across his pathway, the toad that hides in his garden, and the fish that swims in his aquarium. All these are but modifications of one creative thought, showing how the Almighty Worker delights in repeating the same chord, with infinite variations. There are marked physical peculiarities, however, which distinguish man from the other mammals. Thus, the position of the spinal opening in the middle third of the base of the skull, thereby balancing the head and admitting an upright posture; the sigmoid S-curve of the vertebral column; the ability of opposing the well-developed thumb to the fingers; the shortened foot, the sole resting flat on the ground; the size and position of the great toe; the length of the arms, reaching halfway from the hip to the knees; the relatively great development of the brain; the freedom of the anterior extremities from use in locomotion, and the consequent erect and biped position. In addition, man is the only mammal that truly walks; that is endowed with the power of speech; and that is cosmopolitan, readily adapting himself to extremes of heat and cold, and making his home in all parts of the globe.--STEELE'S _Popular Zoology_. FIG. 68. [Illustration: _Skeleton of Orang, Chimpanzee, and Man._] UNION OF FRACTURES (p. 8).--In the course of a week after a fracture, there is a soft yet firm substance, something between ligament and cartilage in consistence, which surrounds the broken extremities of the bone, and adheres to it above and below. The neighboring muscles and tendons are closely attached to its surface, and the fractured extremities of the bone lie, as it were, loose in a cavity in the center, with a small quantity of vascular albumen, resembling a semitransparent jelly. Here, then, is a kind of splint which nature contrives, and which is nearly completed within a week from the date of the accident. We call this new formation the _callus_. This process goes on, the surrounding substance becoming thicker and of still firmer consistence. In the course of a few days more, the thin jelly which lay in contact with the broken ends of the bone has disappeared, and its place is supplied by a callus continuous with that which formed the original capsule. This is the termination of the first stage of curative progress. The broken ends of the bones are now completely imbedded in a mass of vascular organized substance or callus, something between gristle and cartilage in consistence; and as yet there are no traces of bony matter in it. At this time, if you remove the adventitious substance, you will find the broken ends of bone retaining exactly their original figure and presenting the same appearance as immediately after the fracture took place. At the end of about three weeks, if you make a section of the callus, minute specks of earthy matter are visible, deposited in it here and there, and at the same time some of the callus, appears to disappear on the outside, so that the neighboring muscles and tendons no longer adhere to it. The specks of bone become larger and more numerous until they extend into each other; and thus by degrees the whole of the callus is converted into bone. Even at this period, however, there is not absolute bony union, for although the whole of the callus has become bone, it is not yet identified with the old bone, and you might still pick it off with a penknife, leaving the broken extremities not materially altered from what they were immediately after the injury. This may be regarded as the end of the second stage of the process by which a fracture is repaired. Now a third series of changes begins to take place. The broken extremities of the bones become intimately united by bony matter passing from one to the other. The mass of new bone on the outside, formed by the ossification of the callus, being no longer wanted, is absorbed; by degrees the whole of it disappears, and the bone is left having the same dimensions which it had before the occurrence of the accident. The process of union is completed in young persons sooner than in those advanced in life; in the upper extremities sooner than in the lower; and in smaller animals more speedily than in man. In human subjects a broken arm or forearm will be healed in from six to eight weeks, while a leg or thigh will occupy nine or ten weeks.--SIR B. C. BRODIE. FIG. 69. [Illustration: FIG. 69. a. _Monkey's Hand and Foot._ b. _Human Hand and Foot._] THE HAND AND THE FOOT (p. 2l).--_Man Compared with the_ _Ape_.-- The peculiar prehensible power possessed by the hand of man is chiefly dependent upon the size and power of the thumb, which is more developed in him than it is in the highest apes. The thumb of the human hand can be brought into exact opposition to the extremities of all the fingers, whether singly or in combination; while in those quadrumana which most nearly approach man, the thumb is so short, and the fingers so much elongated, that their tips can scarcely be brought into opposition; and the thumb and the fingers are so weak that they can never be opposed to each other with any degree of force. Hence, though well suited to cling round bodies of a certain size, such as the small branches of trees, the anterior extremities of the quadrumana can neither seize very minute objects with such precision nor support large ones with such firmness as are essential to the dexterous performance of a variety of operations for which the hand of man is admirably adapted. The human foot is, in proportion to the size of the whole body, larger, broader, and stronger than that of any other mammal, save the kangaroo. The surface of the astragalus (ankle bone) which articulates with the tibia, looks almost vertically upward, and hardly at all inward, when the sole is flat upon the ground; and the lateral facets are more nearly at right angles to this surface than in any ape. The plane of the foot is directed at right angles to that of the leg; and its sole is concave, so that the weight of the body falls on the summit of an arch, of which the os calcis (heel bone) and the metatarsal bones form the two points of support. This arched form of the foot, and the contact of the whole plantar surface with the ground, are particularly noticeable in man, most of the apes having the os calcis small, straight, and more or less raised from the ground, while they touch, when standing erect, with the outer side only of the foot. The function of the _hallux_, or great toe, moreover, is strikingly contrasted in man and the ape; for, while in the latter it is nearly as opposable as the thumb, and can be used to almost the same extent as an instrument of prehension, it chiefly serves in the former to extend the basis of support, and to advance the body in progression.--DR. W. B. CARPENTER. FIG. 70. [Illustration: _The Leg in standing._] _The Natural Flexibility of the Toes, and How it is Destroyed_.--We often admire the suppleness of the fingers by means of which we can perform such a variety of acts with swiftness and delicacy. Did it ever occur to you that the toes, which in most feet seem incapable of a free and graceful motion, even when they are not stiffened and absolutely deformed by the compression of the modern shoe, are also provided by Nature with a considerable degree of flexibility? The phalanges of the toes, though more feebly developed, have really the same movements among themselves as those of the fingers, and, in case of necessity, their powers can be strengthened and educated to a surprising degree. There are well-known instances of persons who, born without hands, or having lost them by accident, have successfully supplied the deficiency by a cultivated use of their feet. Some of these have distinguished themselves in the world of art. Who that has been so fortunate as to visit the Picture Gallery in Antwerp on some fine morning when the armless artist, M. Felu, was working at his easel, can forget the wonderful dexterity with which he wielded his brushes, mixed the oils on his palette, and shaded the colors on his canvas, all with his agile feet? The writer well remembers the ease and grace with which, at the close of a pleasant interview, this cultured man put the tip of his foot into his coat pocket, drew out a visiting card, wrote his name and address upon it, and presented it to her between his toes! Contrast this intelligent adaptation of a delicate physical mechanism with the barbarous treatment it too commonly receives. The Chinese are at least consistent. They cripple and distort the feet of their highborn daughters until they crush out all the power and gracefulness of nature in the artificial formation of what they term a "golden lily"; but they never expect these golden-lilied women to make their withered feet useful. With us, on the contrary, every girl would like to walk well, to display in her general movements something of the "poetry of motion"; yet the absurd and arbitrary fashion of our foot gear not only makes an elastic step one of the rarest of accomplishments, but renders oftentimes the simple act of walking a painful burden. The calluses, corns, bunions, ingrowing nails, and repulsive deformities that are caused by and hidden under the narrow- toed, high-heeled instruments of torture we often wear for fashion's sake are uncomfortable suggestions that our practices are not greatly in advance of those of our Celestial sisters. Dowie, a sensible Scotch shoemaker, satirizes the shape of a fashionable boot as suited only to "the foot of a goose with the great toe in the middle." The error which may have led to the adoption of this conventional shape appears to lie in a misconception of the natural formation of the foot, and of the relation of the two feet to each other. It is true, that when the toes are covered with their soft parts, the second toe appears a little longer than the first, and this appearance, emphasized and exaggerated, is perhaps responsible for a practical assumption that Nature intended an even-sided, tapering foot. On the contrary, the natural foot gradually expands in breadth from the instep to the toes and, in the skeleton itself, the great toe is the longest. "There is no law of beauty," says Dr. Ellis, "which makes it necessary to reduce the foot to even-sided symmetry. An architect required to provide more space on one than on the other side of a building would not seek to conceal or even to minimize the difference; he would seek rather to accentuate it, and give the two sides of the structure distinctive features....Moreover, the sense of symmetry is, or ought to be, satisfied by the exact correspondence of the two feet, which, taken jointly, may be described as the two halves of an unequally expanded dome."--E. B. S. THE MUSCLES. ATTACHMENT OF THE MUSCLES TO THE BONES (p. 30).--One of the two bones to which a muscle is attached is usually less mobile than the other, so that when the muscle shortens, the latter is drawn down against the former. In such a case, the point of attachment of the muscle to the less mobile bone is called its origin, while the point to which it is fixed on the more mobile bone is called its attachment....A muscle is not always extended between two contiguous bones. Occasionally, passing over one bone it attaches itself to the next. This is the case with several muscles which, originating from the pelvic bone, pass across the upper thigh bone, and attach themselves to the lower thigh bone. In such cases the muscle is capable of two different movements: it can either stretch the knee, previously bent, so that the upper and the lower thigh bones are in a straight line; or it can raise the whole extended leg yet higher, and bring it nearer to the pelvis. But the points of origin and of attachment of muscles may exchange offices. When both legs stand firmly on the ground, the above-mentioned muscles are unable to raise the thigh; instead, on shortening, they draw down the pelvis, which now presents the more mobile point, and thus bend forward the whole upper part of the body. One important consequence of the attachment of the muscles to the bones is the extension thus effected. If the limb of a dead body is placed in the position which it ordinarily occupied during life, and if one end of a muscle is then separated from its point of attachment, it draws itself back, and becomes shorter. The same thing happens during life, as is observable in the operation of cutting the tendons, as practiced by surgeons to cure curvatures. The result being the same during life and after death this phenomenon is evidently due to the action of elasticity. It thus appears that the muscles are stretched by reason of their attachment to the skeleton, and that, on account of their elasticity, they are continually striving to shorten. Now, when several muscles are attached to one bone in such a way that they pull in opposite directions, the bone must assume a position in which the tension of all the muscles is balanced, and all these tensions must combine to press together the socketed parts with a certain force, thus evidently contributing to the strength of the socket connection....This balanced position of all the limbs, which thus depends on the elasticity of the muscles, may be observed during sleep, for then all active muscular action ceases. It will be observed that the limbs are then generally slightly bent, so that they form very obtuse angles to each other. Not all muscles are, however, extended between bones. The tendons of some pass into soft structures, such as the muscles of the face. In this case, also, the different muscles exercise a mutual power of extension, though it is but slight, and they thus effect a definite balanced position of the soft parts, as may be observed in the position of the mouth opening in the face.--ROSENTHAL, _Muscles and Nerves_. MUSCULAR FIBERS (p. 3l).--The anatomical composition of flesh is very similar in every kind of creature, whether it be the muscle of the ox or of the fly; that is to say, there are certain tubes which are filled with minute parts or elements, and the adhesion of the tubes together makes up the substance of the flesh. These tubes may be represented grossly by imagining the finger of a glove, to be called the sarcolemma, or muscle- fiber pouch, and this to be so small as not to be apparent to the naked eye, but filled with nuclei and the juices peculiar to each animal. Hundreds of such fingers attached together would represent a bundle of muscular fibers. The tubes are of fine tissue, but are tolerably permanent; whilst the contents are in direct communication with the circulating blood and pursue an incessant course of chemical change and physical renewal.--EDWARD SMITH, _Foods_. FIG. 71. [Illustration: _Smooth Muscle Fibers (300 times enlarged)._] THE SMOOTH MUSCLE FIBERS consist of long, spindle-shaped cells, the ends of which are frequently spirally twisted, and in the center of which exists a long, rod-shaped kernel or nucleus. Unlike striated muscle, they do not form separate muscular masses, but occur scattered, or arranged in more or less dense layers or strata, in almost all organs. [Footnote: An instance of a considerable accumulation of smooth, muscle fibers is afforded by the muscle pouch of birds, which, with the exception of the outer and inner skin coverings, consists solely of these fibers collected in extensive layers.] Arranged in regular order, they very frequently form widely extending membranes, especially in such tube-shaped structures as the blood vessels, the intestine, etc., the walls of which are composed of these smooth muscle fibers. In such cases they are usually arranged in two layers, one of which consists of ring-shaped fibers surrounding the tube, while the other consists of fibers arranged parallel to the tube. When, therefore, these muscle fibers contract, they are able both to reduce the circumference and to shorten the length of the walls of the tube in which they occur. This is of great importance in the case of the smaller arteries, in which the smooth muscle fibers, arranged in the form of a ring, are able greatly to contract, or even entirely to close the vessels, thus regulating the current of blood through the capillaries. In other cases, as in the intestine, they serve to set the contents of the tubes in motion. In the latter cases the contraction does not take place simultaneously throughout the length of the tube; but, commencing at one point, it continually propagates itself along fresh lengths of the tube, so that the contents are slowly driven forward. As a rule, such parts as are provided only with smooth muscle fibers are not voluntarily movable, while striated muscle fibers are subject to the will. The latter have, therefore, been also distinguished as voluntary, the former as involuntary muscles. The heart, however, exhibits an exception, for, though it is provided with striated muscle fibers, the will has no direct influence upon it, its motions being exerted and regulated independently of the will. Moreover, the muscle fibers of the heart are peculiar in that they are destitute of sarcolemma, the naked muscle fibers directly touching each other. This is so far interesting that direct irritations, if applied to some point of the heart, are transferred to all the other muscle fibers. In addition to this, the muscle fibers of the heart are branched, but such branched fibers occur also in other places; for example, in the tongue of the frog, where they are branched like a tree. Smooth muscle fibers being, therefore, not subject to the will, are caused to contract, either by local irritation, such as the pressure of the matter contained within the tubes, or by the nervous system. The contractions of striated muscle fibers are effected, in the natural course of organic life, only by the influence of the nerves.--ROSENTHAL. OVEREXERTION AND PERSONAL IMPRUDENCE (p. 40).--Among children there is little danger of overexertion. When a little child reaches the point of healthy fatigue, he usually collapses into rest and sleep. But with youth comes the spirit of ambition and emulation. A lad, for instance, is determined to win a race, to throw his opponent in a football scramble, to lift a heavier weight than his strength will warrant; or a girl is stimulated by the passion she may possess for piano playing, painting, dancing, or tennis. The moment of exhaustion comes, but the end is not accomplished, and the will goads on the weary muscles, perhaps to one supreme effort which terminates in a sharp and sudden illness, perhaps to days and weeks of continued and incessant application, during which the whole system is undermined. Thus is laid the foundation for a feeble and suffering maturity. To elderly people, overexertion has peculiar dangers, dependent largely upon the changes which gradually take place in the tissues of the body. The walls of the blood vessels become less and less elastic, and more and more brittle, as life advances, until at last they are ready to give way from any severe or unusual pressure. We constantly see old people hastening their death by personal imprudence. An old gentleman running to catch the morning train; an old farmer hastening to turn the strayed sheep out of a cornfield; the old sportsman having a last run with the hounds; the last pull at the oars; the last attempt of old age to play at vigorous manhood. A prominent American physician has said that between the ages of forty and fifty every wise man will have ceased to run to "catch" trains or street cars; and that between fifty and sixty he will have permanently discarded haste of all kinds. Equal precautions should be observed by both young and old, but especially by those advanced in life, in regard to extremes of heat, cold, or storm. William Cullen Bryant, by exposing himself to a scorching sun and refusing to permit a friend to protect him with an umbrella while delivering an address in Central Park, received injuries to his system that carried him to his grave. Ralph Waldo Emerson, by standing in a chilling wind, contracted a cold and died. George Dawson, by going thoughtlessly into a freezing atmosphere from the sweltering rooms of a crowded reception, took cold which resulted in pneumonia and death. Matthew Arnold, for years a sufferer from heart difficulty, in a single instance neglected the advice of his physician not to indulge in any violent exercise, made repeated attempts and finally succeeded in jumping a fence, and in a few hours was a dead man. Roscoe Conkling braved the most terrible blizzard ever known in the east and sacrificed his life. And yet, these were all men of exceptional prudence. Probably no other five persons in the world of like surroundings and vocations were more careful of their health. In an unguarded moment their prudence left them, and they paid the terrible penalty.--_Compiled_. EFFECTS OF INSUFFICIENT OUTDOOR EXERCISE UPON THE YOUNG (p. 41).--Children deprived of adequate outdoor exercise are always delicate, pale, and tender; or, in a figurative sense, they are like the sprig of vegetation in a dark, dank hole,--bleached and spindling....An inactive indoor life is one of the most effectual ways of weakening the young body. It renders the growth unnaturally soft and tender, and thus susceptible to harm from the slightest causes. It hinders the garnering of strength necessary for a long life, and gives to the germs of disease a resistless power over an organization so weak and deficient....Measles, scarlet fever, and diphtheria find among such a congenial soil, and run riot among the elements of the body held together by so frail a thread....Such children are always at the mercy of the weather. Colds and coughs are standard disorders in winter, headaches and habitual languor in summer....The scapegoat for this result is the climate: if that was only better, mothers are sure their children's health would also be better. No, it would not be better: no earthly climate is good enough to preserve health and strength under such unnatural training....Children of the laboring classes, often dirty and imperfectly clad, seldom have colds, simply for the reason that, for the greater part of the day, they have the freedom of the streets. It is not the dirt, it is not the rags, _but the life-giving force of an active outdoor life_ that renders such children so strong and healthy. --BLACK, _Ten Laws of Health_. POPULAR MODES OF OUTDOOR EXERCISE (p. 42).--_Walking_.--Every person has his own particular step, caused by the conformity, shape, and length of his bones, and the height of his body. Such a thing, then, as a regulation step is unnatural, and any attempt at equalizing the step of individuals of different heights must result in a loss of power. The moment, also, that walking comes to be _uphill_, fatigue is sensibly increased. The center of gravity of the body is changed, and the muscular force necessary to provide for the change causes the fixing of the diaphragm, and a rigid condition of many muscles. Respiration is interfered with, owing to the fixing of the diaphragm, and the heart becomes affected thereby. A person with a sensitive or diseased heart can, during a walk, tell when the slightest rise in the ground occurs. We make climbing more exhausting from the habit we have of suspending the breath. Let the reader _hold his breath_ and run up twenty-four steps of a stair, and then perform the same act _breathing freely_ and deeply. It will be found that by the first act marked breathlessness will be induced, whereas by the latter the effect is much less. This management of the breath constitutes the difference between the beginner and the experienced athlete. The enormous increase of the quantity of air consumed during exercise will at once bring home a number of lessons. One is, that exercise is best taken in the open air, and not in gymnasia; another, that free play to act for the regions of the chest and abdomen must be given. On no account must a tight belt be worn around the soft-walled abdomen. If a belt is preferred to braces, let it be applied below the top of the haunch bone, where the bones can resist the pressure. Whatever may be the pastimes indulged in by young men, walking should never be neglected. The oarsman will become "stale" unless the method of exercise is varied; the gymnast will develop the upper part of his body, while his lower extremities will remain spindleshanks. So with all other forms of exercise; success, in any form of game, sport, or gymnastic training, can not be attained unless walking be freely taken. _Skating_ is simply an exaggerated swinging walk, with this difference, that the foot on which one rests is not stationary, but moves along at a rapid rate. The benefit to the circulation, respiration, and digestion is even greater in skating than in walking. The dangers from skating are: 1. The giving way of the ice. Great caution should be used in regard to the safety of a frozen pond or river. 2. Taking cold from becoming overheated, and from subsequent inactive exposure. Physiological knowledge will teach people that, when they begin to skate, outer wraps should be laid aside, and again put on when skating is finished. 3. Sprains, especially of the ankle, and other minor accidents arising from falls. Ankle boots with strong uppers should be worn during skating. Those who have weak ankles ought to wear skates with ankle straps and buckles, acme skates being relegated to those who are not afraid of going "over their foot." _Rowing_.--The muscles employed in rowing may be summed up under two heads--those that are used in the forward swing, and those used in the backward. In the _forward_ swing all the joints of the lower extremity, the hip, knee, and ankle, are flexed; the shoulder is brought forward; the elbow is straightened; and the wrist is first extended and then flexed, in feathering the oar. The body is bent forward by the muscles in front of the abdomen and spinal column. In the _backward_ movement the reverse takes place; the lower extremity, the hip, knee, and ankle are straightened; the shoulder is pulled back; the elbow is flexed; and the wrist is held straight. The body is bent backward by the muscles at the lower part of the back, and by those of the spine in general. It will be seen that the enormous number of joints put into use, and the varying positions employed, call into play nearly every muscle of the limbs and trunk. Rowing gives more work to the muscles of the back than any other kind of exercise. This is of the first importance to both men and women, but especially to women. The chief work of the muscles of the back is to support the body in the erect position, and the better they are developed the better will the carriage be, and the less likelihood of stooping shoulders, contracted chests, and the like. Now, the work of the muscles in supporting the body is largely relegated in women to the stays, and, in consequence, the muscles undergo wasting and fatty degeneration, in fact, atrophy; so that when the stays are left off, the muscles are unfit to support the body. Rowing exercises these muscles condemned to waste, and imparts a natural carriage to the girl's frame. In rowing, as in horseback riding, the clothing should be loose, stays left off, and flannels worn next the skin. The dress itself should be of woolen, and there should always be in the boat a large wrap to use when one stops rowing. The following practical rules should be observed by rowers: 1. Never row after a full meal. 2. Stop when fatigue comes on. 3. _Allow the breath to escape while the oar is in the water_. A novice usually holds his breath at each stroke, and pulls so rapidly that in a few minutes he becomes breathless, and is forced to stop. Not only is this uncomfortable, but it is dangerous. In the case of both young and old, it may give rise to an abdominal rupture (hernia), dilation of the cavities of the heart, rupture of a heart valve, varicose veins, etc. Instead of fixing the diaphragm and holding the breath during the time of pulling, as novices are apt to do, _do exactly the opposite_. Let the diaphragm go loose, and allow the breath to escape. 4. Change the clothing from the skin outward as soon as the day's rowing is finished. 5. Before retiring for the night, have a warm bath, temperature 92° Fahr. This is a specific against the aches and muscular stiffness which often follow a long pull on the water. _Swimming_.--A word of warning is necessary in regard to those learning to swim in rivers. Boys at school, when they take to river bathing, often carry it to a dangerous extent. They get into the water, and now in, now out on the bank, sometimes remain for hours. This may take place day after day, and if the weather continues warm and the holidays last long enough, the boy may reduce himself to the lowest ebb of feebleness, and possibly develop the seeds of latent disease. He may even die from the effects of this prolonged immersion and madcap exposure. The muscular exertion undergone during swimming, especially by those who swim only occasionally, is very great. The experienced swimmer conserves his strength, as do proficients at all feats, but the occasional swimmer, like the occasional rower, puts forth treble the energy required, and soon becomes exhausted. In the first place, it is a new act for the muscles to perform; they are taken off from the beaten tracks, and are grouped together in new associations; hence they lack adjustment and adaptation. Again, as in other feats for which one is untrained, the heart and lungs do not work in time. Ease and speed in swimming depend upon the attainment of harmony in the working of the muscles, heart, and lungs. Diving is an accomplishment attached to swimming, which involves many dangers, and is well-nigh useless. The customary dive off a springboard into the shallow water of a swimming bath is dangerous in the extreme. The only place where diving should be attempted is into deep water, at least fifteen or twenty feet, where there is no danger of striking the bottom. _Lawn Tennis_.--Of all modern inventions in the way of games, lawn tennis is the best. The dangers attendant on lawn tennis are:-- 1. Overexertion, causing rupture and deranged circulation, especially in the case of those with weak hearts, or those who, being out of condition, or too fat, suddenly engage in the game too long or too violently. 2. Rupture of the _tendon of Achilles_, from taking a sudden bound. In such an accident the subject falls down, with a sensation as if struck with a club on the leg. 3. Rupture of one of the heads of the biceps in the arm. Here the arm drops helplessly, and a muscular knob rises up on the inner and upper part of the arm. 4. The tennis arm. This trouble arises from the method of manipulating the bat. The pain is felt over the upper end of the radius. Many of the strains, ruptured tendons, and torn muscles in tennis players are caused by the want of heels to tennis shoes. As, ordinarily, we walk on heels which vary from half an inch to an inch, there must be a considerable extra strain thrown on the muscles of the calf of the leg, when the heels are left off. Especially during a sudden spring is this apparent, when to rise from off the heels on to the toes requires a greatly increased force. Tennis shoes should therefore have fairly deep, broad heels. _Horseback Riding_ is a mixed exercise, partly active and partly passive, the lower parts of the body being in some measure employed, while the upper parts in easy cantering are almost wholly relaxed. It is peculiarly suited to dyspeptics, from its direct action upon the abdominal viscera, the contents of which are stimulated by the continued agitation and succussion, consequent on the motion in riding. _Bicycling and Tricycling_.--While strongly recommending bicycling and tricycling to both men and women in health, those suffering from heart or lung affections, ruptures, scrofula, joint disease, or like maladies, should not indulge in them without medical sanction. For abdominal complaints, such as dyspepsia, congestion of the liver, constipation, and the like, the exercise is excellent. _Baseball_ is an essentially American game, which brings into play nearly all the muscles of the body. Its chief danger lies in being hit by the hard, forcibly pitched ball, and, for weak persons, in the violence of the exercise. _Football_ is a rough-and-tumble game, suited only to that class of boys and men, who, brimming over with animal life, take small heed of the accidents liable to occur. _Light and Heavy Gymnastics_.--For wet weather, and when outdoor exercise is not practicable, gymnastics are most advisable. Boys and girls, at the age of fifteen or sixteen, often shoot up and become tall and lanky; they want filling out, and are troubled with growing pains. Even men, when tall and thin, are seldom very erect, their muscles are too weak; and there is only one way of overcoming this weakness--by exercising them. Nothing more is wanted than a pair of very light Indian clubs, a pair of light wooden dumb bells, a long wooden rod, and a pair of wooden rings,--the last for combined exercises. Indeed, a systematic motion of the body itself, without any extra artificial resistance, is quite sufficient for the purposes of physical education. In nearly all our large cities are found gymnasia, provided with competent instructors, and every facility for both light and heavy gymnastics. Exercise in a gymnasium is open to the objection of being too brief and too severe, and of simply causing an increase of muscular development. Besides, it is generally unequal in its results, being better adapted to the cultivation of strength in the upper extremities and portion of the body than in the lower. Nevertheless, during inclement weather, or with persons in whom the muscles of the arms and chest are defective, moderate gymnastic exercise is far better than no exercise.--_Compiled_. (_Mostly from "The Influence of Exercise" in The Book of Health_.) THE SKIN. THE HAIR (p. 52).--_Baldness, and its Causes_.--Various reasons are assigned for the baldness which is so prevalent among comparatively young men in our country. One writer says: "The premature baldness and grayness of the Americans as a people is in great measure owing to the nonobservance of hygienic rules, and to excess of mental and physical labor in a climate foreign to the race." Others attribute it to the close unventilated hats commonly worn by men. Dr. Nichols, in the _Popular Science News_, gives his opinion thus: "In our view, it is largely due to modern methods of treatment of the hair and scalp. The erroneous idea prevails, that the skin which holds the hair follicles and the delicate secretory organs of the scalp must be kept as 'clean,' so to speak, as the face or hands; consequently young men patronize barbers or hairdressers, and once or twice a week they have what is called a 'shampoo' operation performed. This consists in a thorough scouring of the hair and scalp with dilute ammonia, water, and soap, so that a heavy 'lather' is produced, and the glandular secretions, which are the natural protection of the hair, and promotive of its growth, are saponified and removed. No act could be more directly destructive of a healthy growth of hair than this....Women do not shampoo or wash the hair as often as the other sex, and consequently they are in a large degree exempt from baldness in middle life. It is true, however, that many women in cities make frequent visits to the hairdressers, and subject their tresses to the 'scouring' process. If this becomes common, it will not be long before baldness will overtake the young mothers as well as the fathers, and the time will be hastened when even children will have no hair to destroy with ammonia or other caustic cosmetics. "The advice we have to offer to young men and maidens is,--let your hair alone; keep at a safe distance from hair-dressing rooms and drug shops, where are sold oils, alkaline substances, alcoholic mixtures, etc., for use upon the hair. They are all pernicious, and will do you harm. The head and hair may be washed occasionally with soft, tepid water, without soap of any kind. As a rule, the only appliances needed in the care of the hair are good combs and brushes: and they should not be used harshly, so as to wound the scalp. Avoid all 'electric' and wire-made brushes. No electricity can be stored in a hairbrush: if it could be, it is not needed." _Sudden Blanching of the Hair from Violent Emotions_.--The color of the hair depends mainly upon the presence of pigment granules, which range in tint from a light yellow to an intense black. A recent investigator has succeeded in extracting the coloring matter of the hair, and has found that all the different shades are produced by the mixture of three primary colors--red, yellow, and black. "In the pure golden yellow hair there is only the yellow pigment; in red hair the red pigment is mixed with more or less yellow, producing the various shades of red and orange; in dark hair the black is always mixed with yellow and red, but the latter are overpowered by the black; and it seems that even the blackest hair, such as that of the negro, contains as much red pigment as the very reddest hair." Hence, "if in the negro the black pigment had not been developed, the hair of all negroes would be a fiery red."--DR. C. H. LEONARD. _The Hair: Its Diseases and Treatment_. The gradual disappearance of this pigment causes the gray or white hair of old age. This natural change in color does not necessarily denote loss of vitality in the hair, as it often continues to grow as vigorously as before it began to whiten. Cases of sudden blanching of the hair from extreme grief or terror are often quoted,--those of Sir Thomas More and of Marie Antoinette being well-known instances in point. An interesting circumstance has been discovered with regard to such cases, namely, that the change of color is not dependent upon the disappearance of the pigment of the hair, which always takes place slowly, but upon the sudden development in its interior of a number of air bubbles, that hide and destroy the effect of the pigment, which itself remains unaltered. Dr. Landois mentions the case of a German printer whom he attended, at a hospital, in the summer of 1865. This man had long been intemperate in his habits, in consequence of which he was seized with delirium tremens. The delirium, as is usual in such cases, was of an extremely terrifying nature, and lasted four days. On the evening of the fourth day the hair was unaltered, but on the morning of the fifth the delirium had disappeared, and his hair, which previously was fair, had become gray. It was examined with the microscope, when it was found that the pigment was still present, but that the central streak of each was filled with air bubbles. How this superabundance of air finds its way into the hair in these cases of sudden blanching, physiologists have not yet been able satisfactorily to explain.--In this connection, however, it may be observed that air bubbles exist, more or less, in all hair, mingled with the pigment granules. The feathers of birds owe their bright colors to an oily secretion corresponding to the pigment in hair, and microscopical observation has revealed the fact that when these colors fade the oily secretion disappears, and is replaced by air. That extreme terror may blanch feathers as well as hair is shown in the case of a poor little starling, which upon being rescued from the claws of a cat became suddenly white. THE NAILS (p. 54).--The nails are mere modifications of the scarfskin, their horny appearance and feeling being due to the fact that the scales or plates of which they are composed are much harder and more closely packed. The root of the nail lies embedded, to the extent of about the twelfth part of an inch, in a fold of the sensitive skin, and, as may be observed from an inspection of the part, the scarfskin is not exactly continuous with the nail, but projects a little above it, forming a narrow margin. The nail, like the scarfskin, rests upon, and is intimately connected with, a structure almost identical with the sensitive skin; this is, however, thrown into ridges, which run parallel to one another, except at the back part, where they radiate from the center of the root. On examining the surface of the nail, a semicircular whitish portion is detected near its root; its color is dependent upon the fact that the ridges there contain fewer blood vessels, and therefore less blood, and on account of its half-moon shape it is called the _lunula_. The nail is constantly increasing in length, owing to the formation of new cells at the root, which push it forward, while the increase in its thickness is due to the secretion of new cells from the sensitive layer beneath, so that the farther the nail grows from the root, the thicker it becomes. Its nutrition, and consequently its growth, suffers in disease, the portion growing during disease being thinner than that growing in health; and accordingly a transverse groove is seen upon the nail, corresponding to the time of an illness. It will thus be seen that by a mere examination of the nail we can astonish our friends by telling them when they have been ill; and it has been estimated that the nail of the thumb grows from its root to its free extremity in five months, that of the great toe in twenty months, so that a transverse groove in the middle of the former indicates an illness about two and a half months before, and in the middle of the latter, about ten months. The culture of the nails, which when perfect constitute so great a beauty, is of much importance; but the tendency is to injure them by too much attention. The scissors should never be used except to pare the free edges when they have become ragged or too long, and the folds of scarfskin which overlap the roots should not, as a rule, be touched, unless they be frayed, when the torn edges may be snipped off, so as to prevent their being torn further, which may cause much pain, and even inflammation. The upper surfaces of the nails should on no account be touched with the knife, as is so often done, the nailbrush being amply sufficient to keep them clean, without impairing their smooth and polished surfaces.--HINTON. BATHS AND BATHING (p. 65).--_Physical Cleanliness Promotes Moral Purity_.--The old adage that cleanliness is next to godliness, must have had its origin in the feeling of moral elevation which generally accompanies scrupulous bodily purity. Frequent bathing promotes purity of mind and morals. The man who is accustomed to be physically clean shrinks instinctively from contact with all uncleanliness. Personal neatness, when grown into a habit, draws after it so many excellences, that it may well be called a social virtue. Without it, refined intercourse would be impossible; for its neglect not only indicates a want of proper self- respect, but a disrespect of the feelings of others which argues a low tone of the moral sense. All nations, as they advance in civilization and refinement of manners, pay increased attention to the purity of the person. What, then, shall we say of people who, after all that has been said and written upon the subject, seldom or never bathe, who allow the pores of the skin to get blocked up with a combination of dust and perspired matter, which is as effectual in its way as plaster to the walls of a building? Could they but once be tempted to taste the delights which arise from a perfectly clean and well-acting skin: the cheerfulness, nay, the feeling of moral as well as physical elevation, which accompanies the sense of that cleanliness, they would soon esteem the little time and trouble spent in the bath, and in the proper care of the surface of the body, as time and labor very well spent--DR. STRANGE. The feet, particularly, should receive daily attention, if it be no more than a vigorous rubbing with a wet cloth, followed by a dry one. After a long walk, also, nothing is more refreshing, especially in summer, than a generous footbath in cool or tepid water, followed by an entire change in shoes and stockings. This is really a necessary precaution, if the feet have become wet from the dampness of the ground; and if the walk has heated the body so that the stockings are moist with perspiration, it is not only an act of prudence, but an instinct of personal neatness. _Ancient Greek and Roman Baths_.--From the earliest historic times the necessity for frequent and thorough ablution has been recognized by artificial provisions for this purpose. The Greeks had "steaming baths" and "fragrant anointing oils," as far back as Homer's time, a thousand years before Christ, but the Romans surpassed all preceding and subsequent nations by their magnificent and luxuriously equipped Thermæ, in which a bath cost less than a cent, and was often free. A full Roman bath included hot air, dry rubbing, hot, tepid, and cold water immersions, scraping with bronze instruments, and anointing with precious perfumes. _The Modern Russian_ and _Turkish baths_ are the nearest approaches we have to the Roman bath. These are found in nearly all our larger cities. _The Turkish Bath_ is conducted in a modified form in this country, generally with hot air instead of steam. Its frequent use not only tends to keep the body in a state of perfect cleanliness, but it imparts a clear, fresh color to the complexion which is hardly attained by other means. "Its most important effect," says a writer in the _Popular Science Monthly_, "is the stimulation of the emunctory action of the skin. By this means we are enabled to wash as it were the solid and fluid tissues, and especially the blood and skin, by passing water through them from within outward to the surface of the body. Hence, in practice, one of the most essential requisites is copious draughts of water during the sweating." During the operation of a Turkish bath, the novice is often astonished at the amount of effete matter eliminated from the pores of the skin. "A surprising quantity of scarfskin, which no washing could remove, peels off, especially if a glove of camel's-hair or goat's-hair be used, as they are in the East, where also the soles of the feet are scraped with pumice. The deposit of this skin of only a week's date, when collected, is often as large as one's fist. Much more solid matter is contained in the perspiration of those who take the bath for the first time, or after a long interval. Nothing escapes through the skin, save what is noxious if retained. This bath should never be used in case of advanced lung diseases, great debility, acute inflammations, or persons who labor under any form of heart disease; but I think its influence is directly curative in rheumatic, gouty, and scrofulous affections, some skin diseases, and the earlier stages of feverish colds and ague. It is said to have calming effects in the treatment of insanity, and the use of it was suggested from the heavy smell the skin of persons thus afflicted often has."--MAPOTHER'S _Lectures on Public Health_. A somewhat heroic bath, used in Siberia to drive away a threatened fever, consists of a thorough parboiling, within an inch or two of a steaming furnace, after which the subject is "drubbed and flogged for about half an hour with a bundle of birch twigs, leaf and all." A douche of cold water is then dashed over the exhausted bather, when he is ready to be put into bed. _Sea Bathing_.--Before the age of seven years, and after fifty-five, sea baths should be used with the greatest caution. All persons unaccustomed to sea bathing should begin with a warm or tepid bath, in doors, proceeding by degrees to the cold indoor bath, and then to the open sea. The sea bath should be taken, if possible, when the sun is shining, when the water has been warmed by contact with the heated sands, and never during the digestion of the principal meal, or late in the evening. Immediately on plunging into the water, which need not, except in persons of full habit, cover the head, brisk motion of some kind should be used. Those who can swim should do so; those who can not, should make as much exertion of the limbs as possible, or rub the body with their hands. The delicate, and particularly those who are recovering from illness, should remove from the bath _as soon as the glow arrives;_ or, if that be not felt at all, then after _one_ plunge. _Danger in Bathing when Overheated_.--It is unwise to bathe when copious perspiration has continued for an hour or more, unless the heat of the weather be excessive, or the sweating has been induced by loading with clothes, rather than by exertion. When much perspiration has been produced by muscular exercise, it is unsafe to bathe, because the body is so fatigued and exhausted, that the reaction can not be insured, and the effect may be to congest the internal organs, and notably the nerve centers. The latter gives cramp. If the weather be chilly, or there be a cold wind, so that the body may be rapidly cooled at the surface while undressing, it is not safe to bathe. Under such conditions, the further chill of immersion in cold water will take place at the precise moment at which the reaction consequent upon the chill of exposure by undressing ought to take place, and this second chill will not only delay or altogether prevent the reaction, but will convert the bath from a mere stimulant to a depressant, ending in the abstraction of a large amount of animal heat and congestion of the internal organs and nerve centers. The aim must be to avoid two chills, and to make sure that the body is in such a condition as to secure a quick reaction on emerging from the water, without relying too much on the possible effect of friction by rubbing. The actual temperature of the water does not affect the question so much as its relative temperature in comparison with that of the surrounding air. It ought to be much lower than that of the air. These maxims receive a striking reenforcement from the case of a young soldier who a few days ago plunged into the river near Manchester, England, after having heated himself by rowing. He was immediately taken with cramps, and was drowned. When taken out, his body was found "twisted," and the vessels of his head showed every evidence of congestion.--_Popular Science Monthly, September, 1883_. _Bather's Cramp_.--Cramp is a painful and tonic muscular spasm. It may occur in any part of the body, but it is especially apt to take place in the lower extremities, and in its milder forms it is limited to a single muscle. The pain is severe, and the contracted muscles are hard and exquisitely tender. In a few minutes the spasm and pain cease, leaving a local sensation of fatigue and soreness. When cramp affects only one extremity, no swimmer or bather endowed with average presence of mind need drown; but when cramp seizes the whole of the voluntary muscular system, as it probably does in the worst cases, nothing in the absence of prompt and efficient extraneous assistance can save the individual from drowning. [Footnote: Even this is often unavailable, as in the case of the Cornell University postgraduate drowned in Hall Creek, Ithaca, June 10, 1888. In this instance the day was hot and oppressive, and the victim sank soon after entering the water. "His companions at once hastened to his relief, and recovered his body in a few minutes. Professor Wilder, of the University, was hurriedly summoned, and every possible method was resorted to in order to induce respiration, but the vital spark had fled. An attack of cramps is supposed to have been the cause of drowning."] Prolongation of muscular exertion, as in continued swimming, and forcible and sudden muscular exertion, as in swimming with very vigorous and rapid strokes, are efficient and frequent causes of cramp. These muscular conditions, however, usually give rise only to the slighter and more localized forms. Serious cramp is a peril which menaces most persons with highly developed muscles. Its most powerful and most avoidable cause is the sudden immersion of the body, when its surface is highly heated, in water of a relatively low temperature.--_Popular Science News._ _Protection of the Ear in Sea Bathing_.--Special attention should be paid by bathers to the exclusion of salt water from the mouth and ears. Many cases of inflammation of the ear, followed by severe and lasting trouble, even to deafness, are chargeable to the neglect of this precaution. Incoming waves should never be received in the face or the ears, and the sea water which enters the ears when floating or diving should be wiped out by soft cotton; indeed, the best plan is to plug the openings of the ears with cotton, which is to be kept there during the bath.--_Science_. _How one who Knows not how to Swim can Escape Drowning_.--It is well for every one to learn the art of swimming, yet it is a knowledge possessed by comparatively few people. Mr. Henry MacCormac, a writer in _Nature_, gives some common sense instructions that, if heeded, may be of great service to those persons who, not knowing how to swim, may find themselves accidentally precipitated into the water. We condense from his article, adding some directions, as follows: In order to escape drowning, it is necessary only to do as the brute does, namely, to walk or tread the water. The brute has no advantage over man in regard to his relative weight, and yet the man perishes while the brute survives. The ignorance of so simple a possibility as that of treading water strikes me as one of the most singular things in the history of man. Perhaps something is to be ascribed to the vague meaning which is attached to the word _Swim_. The dog is wholly incapable of _swimming_ as a man swims, but nothing is more certain than that a man, without previous training or instruction, can swim just as a dog swims, and that by so doing without fear or hesitancy, he will be just as safe as is the dog. The brute thus circumstanced continues to go on all fours, as if he were on land, _keeping his head well out of the water_. So with the man who wishes to save his life and can not otherwise swim. He must strike alternately, with hand and foot,--_one, two, one, two,_--without hurry or precipitation, exactly as the brute does. Whether he be provided with paw or hoof, the beast swims with perfect ease and buoyancy. So, too, can the human being, if he will, with the further immense advantage of having a paddle-formed hand, and of being able, when tired, to rest himself by floating, an act of which the animal has no conception. The printed direction should be pasted up in all boathouses, on every boat, at every bathing place, and in every school: _Tread water when you find yourself out of your depth_. This is all that need be said, unless, indeed, we add: _Float when you are tired_. To float, one needs only to turn upon his back, keeping--as always when in the water--the mouth and chin well up and the lungs full of air.--Every one of us, of whatever age and however encumbered with clothing, may tread water, even in a breaking sea, with as much facility as a fourfooted animal. The position of the water treader is, really, very much safer and better than the sprawling attitude of the ordinary swimmer. But the chief advantage lies in the fact that we can tread water without preliminary teaching, whereas, though we recommend all to learn how to swim, it involves time and pains, entails considerable fatigue, and is, after all, very seldom adequately acquired. HINTS ON CLOTHING (p. 67).--_Advantages of Woolen Fabrics_.--Wool is more irritating than cotton, on account of the stiffness of the hairs with which it bristles; but the excitation it produces becomes a therapeutic means whenever the skin needs a stimulant. The use of wool is particularly desirable in some countries and under some conditions of life. Professor Brocchi, a writer well known for his investigations in malaria, attributes the good health and vigor of the ancient Romans to their habit of wearing coarse woolen clothes; when they began to disuse them, and to wear lighter goods and silks, they became less vigorous and less able to resist the morbid influence of bad air. It was at about the time the women began to dress in notably fine tissues that the insalubrity of the Roman air began first to be complained of. "In the English army and navy," says Dr. Balestra, "the soldiers of garrisons in unhealthy places are obliged constantly to wear wool next to the skin, and to cover themselves with sufficient clothing, for protection against paludine fevers, dysentery, cholera, and other diseases." According to Patissier, similar measures have been found effectual in preserving the health of workmen employed on dikes, canals, and ditches, in marshy lands; while, previous to the employment of these precautions, mortality from fevers was considerable among them. Dr. Balestra has proved by direct experiments in marshy regions that thick and hairy woolen garments arrest in their down a portion of the germs borne in by the air, which thus reaches the skin filtered and purified. The ancient Romans wore ample over-garments over their tunics, and never put them away. It is no less important to be well covered during the night; and precautions of this kind should be recommended to all who live in a swampy country. We are sometimes astonished when we see the natives of particularly warm countries enveloped in woolen, as the Arab in his burnoose, or the Spanish peasant in his tobacco-colored cloak. Such materials protect both against the rays of the sun and against the coolness of the night, and are excellent regulators of heat. It is dangerously imprudent to travel in southern countries without provision of warm clothing.--_Revue des Deux Mondes_. _Weight is not Warmth_.--While speaking of the warmth of clothing for inclement weather, it would be incorrect not to speak of weight in relation to warmth. Many persons mistake weight for warmth, and thus feeble people are actually borne down and weakened by the excess of heavy clothing which is piled on them. Good woolen or fur fabrics retain the heat, and yet are light. When fabrics intended for sustaining warmth are made up of cotton, the mistake of accepting weight for warmth is made. The same errors are often made in respect to bed coverings, and with the same results. _Poisonously Dyed Clothing_.--The introduction of wearing apparel, socks, stockings, and flannels which have been made, by new processes of dyeing, to assume a rich red or yellow color, has led to a local disease of the skin, attended, in rare cases, with slight constitutional symptoms. This disease is due to the dyestuffs. The chief poisonous dyes are the red and yellow coralline, substances derived from that series of chemical bodies which have been obtained of late years from coal tar, and commonly known as the aniline series. The coloring principle is extremely active as a local poison. It induces on the skin a reddish, slightly raised eruption of minute round pimples which stud the reddened surface, and which, if the irritation be severe and long-continued, pass into vesicles discharging a thin watery ichor and producing a superficial sore. The disease is readily curable if the cause of it be removed, and, as a general rule, it is purely local in character. I have, however, once seen it pass beyond the local stage. A young gentleman consulted me for what he considered was a rapidly developed attack of erysipelas on the chest and back. He was, indeed, covered with an intensely red rash, and he was affected with nervous symptoms, with faintness and depression of pulse, of a singular and severe kind. I traced both the local eruption and the general malady to the effect of the organic dye in a red woolen chest and back "comforter." On removing the "comforter" all the symptoms ceased. Similar and even fatal cases have been known from the wearing of highly colored hose. _Uncleanliness of Dress_.--Uncleanly attire creates conditions favorable to disease. Clothing worn too long at a time becomes saturated with the excretions and exhalations of the body, and, by preventing the free transpiration from the surface of the skin, induces oppression of the physical powers and mental inactivity. This observation will be accepted by most persons as true in respect to underclothing; it is equally true in regard to those outer garments which are often worn, unremittingly, until the linings, torn and soiled, are unfit altogether for contact with the cleaner garments beneath them. Health will not be clothed in dirty raiment. They who wear such raiment suffer from trains of minor complaints; from oppression, dullness, headache, nausea, which, though trifling in themselves, taken one by one, when put together greatly reduce that standard of perfect health by which the value of life is correctly and effectively maintained.--RICHARDSON. RESPIRATION. THE VOCAL ORGANS.--_Musical Tones in Speaking_ (p. 76).--Voice is divided into singing and speaking voice. One differs from the other almost as much as noises do from musical sounds. In speaking, the sounds are too short to be easily appreciable, and are not separated by fixed and regular intervals, like those of singing; they are linked together, generally by insensible transitions; they are not united by the fixed relations of the gamut, and can only be noted with difficulty. That it is the short duration of speaking sounds which distinguished them from those of singing, is proved by this, that if we prolong the intonation of a syllable, or utter it like a note, the musical sound becomes evident. So, if we pronounce all the syllables of a phrase in the same tone, the speaking voice closely resembles psalm singing. Every one must have noticed this in hearing schoolboys recite or read in a monotone, and the analogy is complete when the last two or three syllables are pronounced in a different tone. Spoken voice is, moreover, always a chant more or less marked, according to the individual and the sentiment which the words express....It is related of Gretry, that he amused himself by noting as exactly as possible the "Bonjour, monsieur!" (Good day, sir!) of the persons who visited him; and these words expressed by their intonation, in fact, the most opposite sentiments, in spite of the constant identity of the literal sense. _Speech without a Tongue_.--De Jussieu relates that he saw a girl fifteen years old, in Lisbon, who was born without a tongue, and yet who spoke so distinctly as not to excite in the minds of those who listened to her the least suspicion of the absence of that organ. The Transactions of the Royal Society of London (1742) contain an account of a woman who had not the slightest vestige of a tongue, but who could, notwithstanding, drink, eat, and speak as well and as distinctly as any one, and even articulate the words in singing. Other instances have been known where individuals, after losing a portion of the tongue by accident or disease, have again been able to speak after a longer or shorter period.--LE PILEUR. _Stimulants and the Voice_.--"The Drinker's Throat" is a recognized pathological condition, and the Germans have a popular phrase, "He drinks his throat away." Isambert has pointed out the directly local irritant effect of both alcohol and tobacco on the throat, and also the mode by which these agents, on absorption into the system, re-manifest their presence by predisposing to local pharyngeal inflammations. Dr. Krishaber affirms: "It is generally admitted that alcoholic beverages and tobacco irritate the mucous membrane of the throat, directly affect the voice, and leave on it ineffaceable traces. We hold with equal certainty that tea and coffee, although not directly affecting the voice, do so indirectly by acting on the nervous system, and through it the vocal organs, as well as by, some general nervous derangement not very pronounced, but great enough to deprive the singer of the full powers and capabilities of his voice." Dr. Mackenzie says: "The influence of the general health upon the voice is very marked. Alcohol and tobacco should never be used. The hoarse tones of the confirmed votary of Bacchus are due to chronic inflammation of the lining membrane of the larynx; the originally smooth surface being roughened and thickened by the irritation of alcohol, the vocal cords have less freedom of movement, and their vibrations are blurred, or rather muffled, by the unevenness of their contiguous edges." A young American lady of marked musical gifts once asked Adelina Patti's advice upon preparing for the stage. She found the great singer wrapped in furs, although the weather was not severe. After hearing her visitor, Patti replied: "Are you willing to give up _everything_ for your art? If you wish to succeed, you must learn to eat moderately, take no stimulants--not even tea or coffee--keep as regular hours as possible consistent with your public appearance, and even deny yourself the luxury of friends. When you hear of a great vocalist giving extravagant wine suppers, you may be sure that the singer herself takes nothing. To be a successful _artiste_ you must be married, soul and body, to your art." Like the young man to whom Christ spake, the young woman "went away sorrowful," and, balancing the terms, concluded to forego the contest. ABDOMINAL RESPIRATION (p. 8l).--It has often been stated that the respiration of woman differs from that of man, in being limited almost entirely to the chest. In order to investigate this subject scientifically, Dr. Mays, of Philadelphia, devised an ingenious instrument for examining the respiration of the native Indian girls in the Lincoln Institution. The girls had not yet been subjected to the restrictions of civilized dress. He says: "In all, I examined the movements of eighty-two chests, and in each case took an abdominal and a costal tracing. The girls were partly pure and partly mixed with white blood, and their ages ranged from between ten and twenty years. Thus there were thirty-three full-blooded Indians, five one fourth, thirty-five one half, and two three fourths white. _Seventy- five_ showed a _decided abdominal_ type of breathing, three a costal type, and three in which both were about even. _Those who showed the costal type, or a divergence from the abdominal type, came from the more civilized tribes_, like the Mohawks and Chippewas, and were either _one half_ or _three fourths white_; while in _no single instance_ did a full-blooded Indian girl possess this type of breathing. "From these observations it obviously follows that, so far as the Indian is concerned, the abdominal is the original type of respiration in both male and female, and that the costal type in the civilized female is developed through the constricting influence of dress around the abdomen. While these tracings were taken an incident occurred which demonstrated that abdominal constriction could modify the movements of the thorax during respiration. At my first visit to the institution I obtained an exceptional costal type of respiration from a full-blooded Indian girl. At my next visit I concluded to repeat this observation, and found that, contrary to my instructions concerning loose clothing, etc., this girl at my first visit had worn three tight belts around her abdomen. After these were removed she gave the abdominal type of breathing, which is characteristic of nearly all the Indian girls." To us these facts are invaluable. It shows the faulty construction of modern female dress, which restricts the motion of abdominal respiration. It explains why, as experience has taught us, it is necessary to restore this abdominal rhythm, by proper movements, in order permanently to cure the affections of the lower portion of the trunk. It demonstrates conclusively that woman's dress, to be injurious, needs only to interfere with the proper motion of respiration, even though it exercises not the slightest compression.--_Health Record_. THE GERM THEORY OF DISEASE (p. 86).--_What are Disease Germs?_-- Microscopical investigation has revealed throughout Nature, in the air, in water--especially when it contains organic matter, and even within the bodies of persons and animals, myriads of infinitesimal active organisms which live, multiply, and die in endless succession. These have been named _bacteria_ (bacterium, a rod, so called from the general rod shape first observed), and also _microbes_ (microbe, a small living object). Some investigators apply the latter term as a general one, limiting the former to such microbes as are believed to be special disease producers. The "Germ Theory" teaches that the seeds or _spores_ of bacteria, floating in the air we breathe or in the water we drink, are taken into our bodies where, under conditions favorable to their growth, they develop, multiply, and, each after its own species, produce distinctive evil results.--Thus, according to this theory, there are special varieties of microbes that cause, respectively, diphtheria, erysipelas, scarlatina, cholera, etc.--One of the most common microbes in nature is the bacterium of putrefaction, found everywhere in decaying organic matter. [Footnote: This is the microbe found in impure water. If we take half a glass of spring or river water, and leave it uncovered for a few days, we shall observe upon it a thin coating of what appears to be a fine dust. Place, now, a drop of this dusty water under a cover glass, and examine it under a microscope with a magnifying power of about five hundred diameters. The revelation is astonishing. "The whole field of the microscope is in motion; hundreds of bacteria, resembling minute transparent worms, are swimming in every direction with an undulatory motion like that of an eel or snake. Some are detached, others united in pairs, others in chains or chaplets or cylindrical rods....All these forms represent the different transformations of _Bacterium termo_, or the microbe of putrefaction. Those which are dead appear as small, rigid, and immovable rods."--TROUESSART.] By the species of microbes called ferments all fermented liquors are artificially produced (see p. 132); these also cause the "rising" of bread.--These wonderful little existences are thus made to perform an important part in the economy of Nature. "Nourished at the expense of putrefying organic matter, they reduce its complex constituents into soluble mineral substances, which they return to the soil to serve afresh for the nourishment of similar plants. Thus they clear the surface of the earth from dead bodies and fecal matter, and from all the useless substances which are the refuse of life; and thus they unite animals and plants in an endless chain."--TROUESSART. _How Disease Germs Grow_.--Experiments having shown that no life is known to spring from inanimate matter, we may reasonably suppose that just as wheat does not grow except from seed, so no disease occurs without some disease germ to produce it. Then, again, we may logically assume that each disease is due to the development of a particular kind of germ. If we plant smallpox germs, we do not reap a crop of scarlatina or measles; but, just as wheat springs from wheat, each disease has its own distinctive germs. Each comes from a parent stock, and has existed somewhere previously....Under ordinary circumstances, these germs, though nearly always present, are comparatively few in number, and in an extremely dry and indurated state. Hence, they may frequently enter our bodies without meeting with the conditions essential to their growth; for experiments have shown that it is very difficult to moisten them, and till they are moistened, they do not begin to develop. In a healthy system they remain inactive. But anything tending to weaken or impair the bodily organs, furnishes favorable conditions, and thus epidemics almost always originate and are most fatal in those quarters of our great cities where dirt, squalor, and foul air render sound health almost an impossibility.... Having once got a beginning, epidemics rapidly spread. The germs are then sent into the air in great numbers, and in a moist state; and the probabilities of their entering, and of their establishing themselves even in healthy bodies, are vastly increased....Climate and the weather have also much influence on the vitality of these germs. Cold is a preventive against some diseases, heat against others. Tyndall found that sunlight greatly retarded and sometimes entirely prevented putrefaction; while dirt is always favorable to the growth and development of germs. _Sunshine and cleanliness are undoubtedly the best and cheapest preventives against disease.--"Disease Germs" Chambers's Journal_. You know the exquisitely truthful figures employed in the New Testament regarding leaven. A particle hid in three measures of meal leavens it all. A little leaven leaveneth the whole lump. In a similar manner a particle of contagium spreads through the human body, and may be so multiplied as to strike down whole populations. Consider the effect produced upon the system by a microscopic quantity of the virus of smallpox. That virus is to all intents and purposes a seed. It is sown as leaven is sown, it grows and multiplies as leaven grows and multiplies, and it always reproduces itself....Contagia are living things, which demand certain elements of life, just as inexorably as trees, or wheat, or barley; and it is not difficult to see that a crop of a given parasite may so far use up a constituent existing in small quantities in the body, but essential in the growth of the parasite, as to render the body unfit for the production of a second crop. The soil is exhausted; and until the lost constituent is restored, the body is protected from any further attack from the same disorder. To exhaust a soil, however, a parasite less vigorous and destructive than the really virulent one may suffice; and if, after having, by means of a feebler organism, exhausted the soil without fatal result, the most highly virulent parasite be introduced into the system, it will prove powerless. This, in the language of the germ theory, is the whole secret of vaccination.--TYNDALL. _Disease Germs Contained in Atmospheric Dust_.--Take the extracted juice of beef or mutton, so prepared as to be perfectly transparent, and entirely free from the living germs of bacteria. Into the clear liquid let fall the tiniest drop of an infusion charged with the bacteria of putrefaction. Twenty-four hours subsequently, the clear extract will be found muddy throughout, the turbidity being due to swarms of bacteria generated by the drop with which the infusion was inoculated. At the same time the infusion will have passed from a state of sweetness to a state of putridity. Let a drop similar to that which has produced this effect fall into an open wound: the juices of the living body nourish the bacteria as the beef or mutton juice nourished them, and you have putrefaction produced within the system. The air, as I have said, is laden with floating matter which, when it falls upon the wound, acts substantially like the drop....A few years ago I was bathing in an Alpine stream, and, returning to my clothes from the cascade which had been my shower bath, I slipped upon a block of granite, the sharp crystals of which stamped themselves into my naked shin. The wound was an awkward one, but, being in vigorous health at the time, I hoped for a speedy recovery. Dipping a clean pocket handkerchief into the stream, I wrapped it round the wound, limped home, and remained for four or five days quietly in bed. There was no pain, and at the end of this time I thought myself quite fit to quit my room. The wound, when uncovered, was found perfectly clean, uninflamed, and entirely free from pus. Placing over it a bit of gold beater's skin, I walked about all day. Toward evening, itching and heat were felt; a large accumulation of pus followed, and I was forced to go to bed again. The water bandage was restored, but it was powerless to check the action now set up; arnica was applied, but it made matters worse. The inflammation increased alarmingly, until finally I was ignobly carried on men's shoulders down the mountain, and transported to Geneva, where, thanks to the kindness of friends, I was immediately placed in the best medical hands. On the morning after my arrival in Geneva, Dr. Gautier discovered an abscess in my instep, at a distance of five inches from the wound. The two were connected by a channel, or _sinus_, as it is technically called, through which he was able to empty the abscess without the application of the lance. By what agency was that channel formed--what was it that thus tore asunder the sound tissue of my instep, and kept me for six weeks a prisoner in bed? In the very room where the water dressing had been removed from my wound and the gold beater's skin applied to it, I opened this year a number of tubes, containing perfectly clear and sweet infusions of fish, flesh, and vegetable. These hermetically sealed infusions had been exposed for weeks, both to the sun of the Alps and to the warmth of a kitchen, without showing the slightest turbidity or signs of life. But two days after they were opened, the greater number of them swarmed with the bacteria of putrefaction, the germs of which had been contracted from the dust-laden air of the room. And, had the pus from my abscess been examined, my memory of its appearance leads me to infer that it would have been found equally swarming with these bacteria--that it was their germs which got into my incautiously opened wound. They were the subtile workers that burrowed down my shin, dug the abscess in my instep, and produced effects which might well have proved fatal to me.--TYNDALL. _Disease Germs Carried in Soiled Clothing_ (p. 89).--The conveyance of cholera germs by bodies of men moving along the lines of human communication, without necessarily affecting the individuals who transport them, is now easy to understand; for it is well established that clothes or linen soiled by cholera patients may not only impart the germs with which they are contaminated to those who handle them when fresh, but that, after having been dried and packed, they may infect persons at any distance who incautiously unfold them. Thus, while the nurses of cholera patients may, with proper precautions, enjoy an absolute immunity from attack, the disease germs may be introduced into new localities without any ostensible indication of their presence. It is obvious that the only security against such introduction consists in the destruction or thorough disinfection of every scrap of clothing or linen which has been about the person of a cholera patient.--DR. CARPENTER. I have known scarlet fever to be carried by the clothing of a nurse into a healthy family, and communicate the disease to every member of the family. I have known cholera to be communicated by the clothes of the affected person to the women engaged in washing the clothes. I have known smallpox conveyed by clothes that had been made in a room where the tailor had by his side sufferers from the terrible malady. I have seen the new cloth, out of which was to come the riding habit for some innocent child to rejoice in as she first wore it, undergo the preliminary duty of forming part of the bed clothing of another child stricken down with fever. Lastly, I have known scarlet fever, smallpox, typhus, and cholera, communicated by clothing contaminated in the laundry.--DR. RICHARDSON. THE SANITARY HOME (see p. 94).--1. _The Site_.--First and foremost of all the things you are to consider, is the healthfulness of a situation. The brightest house and cheeriest outlook in nature will be made somber by the constant presence of a doctor, and the wandering around of an unseen, but ever felt, specter in the shape of miasm....Malaria-malus, bad; aria, air--means, in its common definition, simply bad air. Miasma is its synonym,--infecting effluvia floating in the air. Because, as everybody knows, certain places have always chills and fever associated with them, and other places have not, it follows that between such places there is some fact of difference; this fact is the presence of miasm, a cause of disease, having a signification associative with the locality.... Vegetation, heat, and moisture: these are the three active agents in the production of miasma, to which a fourth is to be added, in the influence of non-drainage, either by the way of the atmosphere or running water. The strongest example of a malarious locality one might make would be in suggesting a marshy valley in a tropical climate, so overrun with fixed water as to destroy a prolific vegetation, yet not covering it enough to protect the garbage from the putrefying influences of the sun; this valley, in turn, so environed with hills as to shut off a circulation of air....Ground newly broken is not unapt to generate miasm. This results from the sudden exposure of long-buried vegetable matter to the influences of moisture and heat....It may readily be conceived that malarious situations exist where the miasm is not sufficient in quantity to produce the effects of intermittent or bilious fever, yet where there is quite enough of it to keep a man feeling good for nothing,--he is not sick, but he is never well. I know of one country seat of this kind, where forty thousand dollars would not pay for the improvements put upon it, and where, I am free to declare, I would not think of living, even if, as an inducement, a free gift were made to me of the place....Besides miasm, there are other atmospheric associations to be considered. I recall this moment a distillery, where attempt was made to get clear of the mash by throwing it into a running stream, with the anticipation of its being carried to the river, but where, on the contrary, it became a stagnant putrescent mass, impregnating the air for miles with its unendurable odor, and inducing such a typhoid tendency that half the countryside were down with fever....There are, again, situations where the filth and debris of sewage exercise a poisoning influence on the surrounding atmosphere. This has its principal application to the neighborhood of cities and towns drained into adjoining streams. London and the Thames furnish a notable illustration. A cove, attractive as it is, may prove a receptacle for the accumulation of dead fish and other offal, which shall make untenable the charming cottage upon the bank. A deep cove has rarely healthy surroundings, the circulation of its water being too sluggish to insure freshness and vitality. Water, like blood, to be healthy, must be in a state of continuous movement. A nonobservant man, purchasing a beautiful stream, may be completely disappointed by finding that the opacity of its water depends upon a factory, of which he had never so much as heard; he may not let his children bathe in it, for he may well fear for them the fate of the fish he so plentifully finds lying dead upon the shore. A poisoned rural stream is as sad a sight as it has grown to be a common one. Always, before buying water, know what there is up stream, or what there is likely to be. Never buy a country house without seeing to it that the foundation stands upon a higher level than some channel which may drain it, and this, by the way, is not to consider alone the dry summer day on which you go first to visit the place; you are to think of the winter and spring. Look to it that no excess of water shall be able to drown you out; some places, which in dry weather are glorious, are, in winter and spring, ankle deep in slush and mire, and everything about them is as wet as a soaked board. Open the front door of such a house, and a chill strikes you instantly. A fire must be kept the year round, or otherwise you live in the moisture of a vault. Places there are of this class where the question of the water from the kitchen pump comes to absorb the attention of the whole household. No shade is an abomination. A bilious fever fattens in the sun as does miasm in a marshy valley. Too much shade, on the contrary, and too near the house, is equally of ill import; it keeps things damp, and dampness is a breeder of pestilence. An atmosphere confined about a house by too dense foliage is, like the air of an unventilated room, not fit for practical purposes. The sporadic poisons have an intimate relationship with dampness; miasm lives in it as does a snail in his shell. Besides this, it shuts out the cool breath of the summer nights, and makes restless swelterers where even a blanket might be enjoyed.--DR. JOHN DARBY, _Odd Hours of a Physician_. 2. _The House_.--So construct the dwelling from foundation to roof that no dampness can result. Give to the cellar dry walls, a cement floor, and windows enough to insure constant currents of air. Insist upon such a system of immediate and perfect sewerage as shall render contamination impossible. If "modern improvements" are afforded, see that the plumbing embraces the latest and most scientific sanitary inventions. Do not economize on this point; health, perhaps life, depends upon the perfect working of the various traps. Having employed the most skilled and intelligent plumbers, overlook their work so that you may fully understand the principle applied. Provide for ample ventilation in every apartment, above and below. Let the sleeping rooms be above stairs, and furnished with appliances for moderate warmth in winter. Treat yourself and your family to as many fireplaces as possible. Indulge in a spacious piazza, so placed that it will not cut off the light from the family sitting room, and, if you can, include a balcony or two, large enough to hold a chair and a table, or a workbasket. Remember that a house is for convenience and protection _only when you can not be in the open air_. 3. _The kitchen and the Dust Heap.--Removal of Household Refuse_.--It has to be assumed, especially where servants are not carefully overlooked, that the dust heap of most houses will contain more or less decomposing organic matter, such as bits of meat, scales and refuse of fish, tea and coffee grounds, and the peelings of vegetables, which, though quite out of place in the ash heap, are apt surreptitiously to be thrown upon it. Such matter soon becomes offensive and even dangerous, and a few days' retention of it in warm weather constitutes a legal nuisance. Household refuse should be carted away as often as once in two days; in extreme hot weather, daily. Where it is inexpedient to remove it frequently, it should be kept covered to the depth of two or three inches with a layer of powdered charcoal, or freshly burnt lime, or, at least, of clear dry earth. All soil which has become foul by the soakage of decaying or vegetable matter should be similarly treated. The refuse heap should be protected from rain, and liquids should never be thrown upon it. Where obnoxious matter has been allowed to accumulate, its disturbance for removal should be conducted with special precaution, both on account of its temporary offensiveness of odor and the more serious results which may follow. It can not be too distinctly understood that cleanliness, ventilation, and dryness are the best of all deodorizers. One of the first of household regulations should be to see that no unsanitary rubbish remains in or about the dwelling. Keep the dust heap itself at the farthest practicable remove from the house. Sow grass seed plentifully upon the back premises, and induce tidiness in the domestics by having the kitchen door open upon a well-kept lawn. _Burning of Garbage_.--The easiest, quickest, and most sanitary method of disposing of household garbage is to burn it This plan has been officially recommended by the Boards of Health in various cities. Many housekeepers have adopted it, and find it so practicable that in New York City there has become a marked decrease in the amount of household refuse collected by the scavengers. If, after every meal, the draughts of the range be opened, and all waste matter be deposited within, a few moments, or at most, a half hour, will effectually dispose of it, and prevent all the dangers that arise from its retention and accumulation. In the country, where there is plenty of ground, nearly all rubbish can be destroyed in this way and by outside fires, with the additional advantage that the--E. R. S. 4. _The Sewers and Drains.--How to Keep out Sewer Air_.--The most perfectly flushed sewers that are made, under the latest and fullest sanitary light, must, owing to the constant entrance of greasy and other adhesive material, contain more or less of particles that "stick," and also more or less of fungi and mold; so that here, shut away from light and air, goes on the peculiar fermentation that fits it for the soil or habitat of the malarial germ. These germs, the soil once ready, take possession and multiply, whether that soil be a sewer or the blood of a person who sits calmly unconscious in a gorgeous chamber above, with a small continuation of the sewer extending untrapped up to his washbowl.-- DR. DERBY. Keep constant watch of your traps and drains. Cultivate the faculty of detecting sewer gas in the house. Always fear a smell; trace it to its source and provide a remedy. At the same time, bear in mind that it is not always the foul smell that is most dangerous. There is a close, sweet odor often present in bathrooms, and about drains, that is deadly as the Upas tree. Bad air from neglected drains causes not only fevers, dysentery, and diphtheria, but asthma and other chronic disorders. Illuminating gas, escaping from pipes and prevented from exuding by frozen earth, has been known to pass sidewise for some distance into houses. Thus also the air from cesspools and porous or broken drains finds its way, when an examination of the household entrance to the drain fails to reveal the cause of an existing effluvia. But, however bad the drain may be outside the house, there is little to fear provided the gas can escape externally. Every main drain should have a ventilating pipe carried from it directly outside the house to the top of the highest chimney. The soil pipe inside the house should be carried up through the roof and be open at the top. Digging for drains or other purposes should not be allowed when the mercury stands above 60°; but if, as in repairs of pipes, it becomes necessary to dig about the house in hot weather, let it be done in the middle of the day, and replace the turf as speedily as possible. If the soil be damp, or the district malarious, sprinkle quicklime upon the earth as fast as it is turned. _How to Clear Waste Pipes_.--The "sewer gas," about which so much has been written, and which is so justly dreaded, is not, as many suppose, the exclusive product of the sewer. Indeed, the foul and dangerous gases are not only found in the sewers themselves, but in the unventilated waste pipes, and those which are in process of being clogged by the foul matter passing through them. Any obstruction in the soil or waste pipes is therefore doubly dangerous, because it may produce an inflow of foul gas into the pipe, even though the entrance to the sewer itself has been entirely cut off. In pipes leading from the house to the cesspool, there is a constant accumulation of grease. This enters as a liquid, but hardens as the water cools, and is deposited on the bottom and sides of the pipes. As these accumulations increase, the water way is gradually contracted, till the pipe is closed. When the pipe is entirely stopped, or allows the water to fall away by drops only, proceed thus: Empty the pipe down to the trap, as far as practicable, by "mopping up" with a cloth. If the water flows very slowly, begin when the pipe has at last emptied itself. Fill the pipe up with potash, crowding it with a stick. Then allow hot water to trickle upon the potash, or pour the hot water upon it in a small stream, stopping as soon as the pipe appears to be filled. As the potash dissolves and disappears, add more water. At night a little heap of potash may be placed over the hole, and water enough poured on so that a supply of strong lye will flow into the pipe during the night. Pipes that have been stopped for months may be cleaned out by this method, though it may call for three or four pounds of potash. The crudest kind, however, appears to act as well as the best. If the pipe is partially obstructed, a lump of crude potash should be placed where water will drip slowly upon it, and so reach the pipe. As water comes in contact with the potash, it becomes hot, thus aiding in dissolving the grease. Potash, in combination with grease, forms a "soft" or liquid soap, which easily flows away. It is also destructive to all animal and most mineral matters. Some of the most dangerous gases come from wash-basin pipes, being, perhaps, the result of the decay of the soap and the animal matter washed from the skin. When a pipe is once fairly cleaned out, the potash should be used from time to time, in order to dissolve the greasy deposits as they form, and carry them forward to the cesspool or sewer.--_Artisan_. _What Came from a Neighbor's Cesspool_.--Keep watch not only of your own premises, but stand on guard against those of your neighbors. Dr. Carpenter cites a case wherein "four members of a certain household were attacked with typhoid fever, one of whom narrowly escaped with her life. The circumstances left no doubt in the mind of the attending physician that the malady originated in the opening of an old cesspool belonging to a neighboring house, then in course of demolition. The house in which the outbreak took place is large and airy, and stands by itself in a most salubrious situation. The most careful examination failed to disclose any defect either in its drainage or its water supply; there was no typhoid in the neighborhood; and the milk supply was unexceptional. But the neighboring house being old, and having been occupied by a school, its removal had been determined on to make way for a house of higher class; and as the offensive odor emanating from the uncovered cesspool was at once perceived in the next garden, and the outbreak of typhoid followed at the usual interval, the case seems one which admits of no reasonable question." 5. _The Cellar_.--_A Typical Bad Cellar_.--Did the reader ever, when a child, see the cellar afloat at some old home in the country? You creep part way down the cellar stairs with only the light of a single tallow candle, and behold by its dim glimmer an expanse of dark water, boundless as the sea. On its surface, in dire confusion, float barrels and boxes, butter firkins and washtubs, boards, planks, hoops, and staves without number, interspersed with apples, turnips, and cabbages, while half-drowned rats and mice, scrambling up the stairway for dear life, drive you affrighted back to the kitchen....Now consider the case of one of these old farmhouse cellars that has been in use fifty years or more. In it have been stored all the potatoes, turnips, cabbages, onions, and other vegetables for family food. The milk and cream, the pork and beef, and cider and vinegar, have all met with various accidents, and from time to time have had their juices, in various stages of decay, absorbed by the soil of the cellar bottom. The cats have slept there to fight the rats and the mice, who have had their little homes behind the walls for half a century; and the sink spouts have for the same term poured into the soil close by, their fragrant fluids. The water rushes upward and sideways into the cellar, forming, with the savory ingredients at which we have delicately hinted, a sort of broth, quite thin and watery at first, but growing thicker as the water slowly subsides and leaves its grosser parts pervading the surface of the earth, walls, and partitions. All this time the air rushes in at the openings of the cellar, and presses constantly upward, often lifting the carpets from the floors, and is breathed day and night by all who dwell in the house. Does it require learned doctors or boards of health to inform any rational person that these conditions are unfavorable to health?--MRS. PLUNKETT, _Women, Plumbers, and Doctors_. _What Came from a Crack in a Cellar Wall_.--A few years ago a Boston gentleman inherited a house, situated on one of the most desirable streets of the city. Resolving to make a healthy as well as a beautiful home, he. spent a large sum, and gave personal supervision to all the details of an elaborate system of plumbing. He moved in. Imagine his grief and disappointment when member after member of his family succumbed to diphtheria, and an infant and a grown daughter died. Though so deeply smitten, he did not lose his belief in the connection between cause and effect. He ordered a minute investigation of the premises by experts. A slight crack, so small as to have escaped ordinary observation, was found in the cellar wall. Investigation of the premises next door--the inmates of which were also suffering from diphtheria--showed a choked-up drain, which ought to have connected with the sewer, but did not. The filthy ooze from this was pouring out, just where its effluvium and its disease germs could pass without any hindrance through the crack. Now that it is shown that gases pass through bricks and many kinds of stone, it is easy to see that the sanitary welfare of one is the sanitary welfare of all.--MRS. PLUNKETT. 6. _The Bedroom_.--_The Bed a Night Garment_.--There is still one of our garments to be considered, which generally is not regarded as such. I mean the bed--that piece of clothing in which we spend such a great part of our time. The bed is not only a place of rest; it is especially our sleeping garment, and has often to make up for privations endured during the day and the day's work, and to give us strength for to-morrow. Like our day garments, the bed covering must be airy and warm at the same time. We warm the bed by our body, just as we warm our clothes, and the bed warms the air which is continually flowing through it from below, upward. The regulating strata must be more powerful in their action than in our day clothes, because during rest and sleep the metamorphosis of our tissues and the resulting heat become less; and because in a horizontal position we lose more heat by an ascending current of air than in a vertical position, where the warm ascending current is in more complete and longer contact with our upright body. The warmth of the bed sustains the circulation in our surface to a certain degree for the benefit of our internal organs at a time when our production of heat is at its lowest ebb. Hence the importance of the bed for our heat and blood economy. Several days without rest in a bed not only make us sensible of a deficiency in the recruiting of our strength, but very often produce quite noticeable perturbations in our bodily economy, from which the bed would have protected us.--DR. MAX VON PETTENKOFFER. _Bed Ventilation_.--It often happens that the desire of the energetic housekeeper to have her work done at an early hour in the morning, causes her to leave one of the most important items of neatness undone. The most effectual purifying of bed and bedclothes can not take place, if the proper time is not allowed, for the free circulation of pure air, to remove all human impurities which have collected during the hours of slumber. At least two or three hours should be allowed for the complete removal of atoms of insensible perspiration which are absorbed by the bed. Every day the airing should be done; and, occasionally, bedding constantly used should be carried into the open air, and left exposed to the sun and wind for half a day.--_Home and Health_. CIRCULATION. THE PULSE (p. 116).--The pulse which is felt by the finger does not correspond precisely with the beat of the heart, but takes place a little after it, and the interval is longer, the greater the distance of the artery from the heart. The beat of the artery on the inner side of the ankle, for example, is a little later than the beat of the artery in the temple.--HUXLEY. The pulse is increased by exertion, and thus is more rapid in a standing than in a sitting, and in a sitting than in a lying posture. It is quickened by meals, and while varying thus from time to time during the day, is on the whole quicker in the evening than in early morning. It is said to be quicker in summer than in winter. Even independently of muscular exertion, it seems to be quickened by great altitude. Its rate is also profoundly influenced by mental conditions.--FOSTER. CIRCULATION OF THE BLOOD IN THE BRAIN (p. l20).--Signer Mosso, who has been engaged on the subject for six years, has published some new observations on the different conditions of the circulation of the blood in the brain. He has had the privilege of observing three patients who had holes in their skulls, permitting the examination of the encephalic movements and circulation. No part of the body exhibits a pulsation so varied in its form as the brain. The pulsation may be described as tricuspid; that is, it consists of a strong beat, preceded and followed by lesser beats. It gathers strength when the brain is at work, corresponding with the more rapid flow of blood to the organ. The increase in the volume of the brain does not depend upon any change in the respiratory rhythm; for, if we take the pulse of the forearm simultaneously with that of the brain, we can not perceive that the cerebral labor exercises any influence upon the forearm, although the pulsation in the brain may be considerably modified. The emotions have a similar effect upon the circulation of the brain to that of cerebral labor. Signor Mosso has also observed and registered graphically the variations of the cerebral pulse during sleep. Generally the pulses of the wrist and the brain vary oppositely. At the moment of waking, the pulse of the wrist diminishes, while that of the brain increases. The cerebral pulsations diminish as sleep grows deeper, and at last become very weak. Outward excitations determine the same modifications during sleep as in the waking state, without waking the sleeper. A deep inspiration always produces a diminution in the volume of the brain, in consequence, probably, of the increased flow of blood into the veins of the thoracic cavity; the increase of volume in the brain, when it takes place, is, on the contrary, due to a more abundant flow of arterial blood to the encephalus.--_Popular Science Monthly, March, 1882_. CATARRHAL COLDS (p. l30).--I maintain that it can be proved, with as absolute certainty as any physiological fact admits of being proved, that warm, vitiated indoor air is the cause, and cold outdoor air the best cure, of catarrh....Fresh cold air is a tonic that invigorates the respiratory organs when all other stimulants fail, and, combined with arm exercise and certain dietetic alternatives, it is the best remedy for all disorders of the lungs and upper air passages....A combination of the three specifics,--exercise, abstinence, and fresh air,--will cure the most obstinate cold....Frost is such a powerful disinfectant, that in very cold nights the lung-poisoning atmosphere of few houses can resist its purifying influence; in spite of padded doors, in spite of "weatherstrips" and double windows, it reduces the indoor temperature enough to paralyze the floating disease germs. The penetrative force of a polar night frost exercises that function with such resistless vigor that it defies the preventive measures of human skill; and all Arctic travelers agree that among the natives of Iceland, Greenland, and Labrador pulmonary diseases are actually unknown. Protracted cold weather thus prevents epidemic catarrhs, but during the first thaw Nature succumbs to art: smoldering stove fires add their fumes to the effluvia of the dormitory, tight- fitting doors and windows exclude the means of salvation; superstition triumphs; the lung poison operates, and the next morning a snuffling, coughing, and red-nosed family discuss the cause of their affliction....It is a mistake to suppose that "colds" can be propagated only by direct transmission or the breathing of recently Vitiated air. Catarrh germs, floating in the atmosphere of an ill-ventilated bedroom, may preserve their vitality for weeks after the house has been abandoned; and the next renter of such a place should not move in till wide-open windows and doors and a thorough draught of several days have removed every trace of a "musty" smell.--DR. FELIX L. OSWALD, _Remedies of Nature, Popular Science Monthly, March, 1884_. CATCHING COLD.--The phrase "to catch cold," so often in the mouths of physicians and patients, is a curious solecism. It implies that the term "cold" denotes something positive--a sort of demon which does not catch, but is caught by the unfortunate victims....If most persons outside of the medical profession were to be asked what they consider as chiefly to be avoided in the management of sick people, the answer would probably be "catching cold." I suspect that this question would be answered in the same way by not a few physicians. Hence it is that sick rooms are poorly ventilated, and patients are oppressed by a superabundance of garments and bedclothes. The air which patients are made to breathe, having been already breathed and rebreathed, is loaded with pulmonary exhalations. Cutaneous emanations are allowed to remain in contact with the body, as well as to pervade the atmosphere. Patients not confined to the bed, especially those affected with pulmonary disease, are overloaded with clothing, which becomes saturated with perspiration, and is seldom changed, for fear of the dreaded "cold."... A reform is greatly needed in respect to "catching cold." Few diseases are referable to the agency of cold, and even the affection commonly called a cold is generally caused by other agencies, or, perhaps, by a special agent, which may prove to be a microbe. Let the axiom, _A fever patient never catches cold_, be reiterated until it becomes a household phrase. Let the restorative influence of cool, fresh, pure atmosphere be inculcated. Let it be understood that in therapeutics, as in hygiene, the single word _comfort_ embodies the principles which should regulate coverings and clothing.--AUSTIN FLINT, M.D., _in a Lecture printed in The New York Medical Journal_. DIGESTION AND FOOD. THE WATER WE DRINK (p. l55).--_Qualities of Pure Water_.--"A good drinking water," says Dr. Simpson (in _The Water We Drink_), "should possess the following physical characters: it should be entirely free from color, taste, or odor; it should, moreover, be cool, well aerated, soft, bright, and entirely free from all deposit. But it should be remembered that a water having all these characteristics may yet be more or less polluted by organic matter, owing to the proximity of drains and sewers....Disease has frequently been traced to the use of perfectly bright and clear water, where there was no sediment, and where the animal organic matter was held in a state of solution." In the case of diseases, such as typhoid, which attack the stomach, disease germs are removed along with the excreta; and if, as is often the case, the drainage of an infected town flows into a river, and that river is used in some after portion of its course as a water supply, there is great danger of such diseases being communicated. For, however well the water may be purified and filtered, we have no guarantee that it will not contain some of these disease germs, which are so small that they pass through the finest filters. It is in this way that almost all the great cholera and typhoid epidemics have spread.--_Chambers's Journal_. _Well Water Often Dangerous_.--A densely crowded population soon impregnates the soil to some depth with filth, which drains into the water course below, especially if such water is near the surface. This surface water easily penetrates a loosely walled well. Every well, therefore, should not only be widely separated from barnyards, cesspools, pens, sinks, and similar places, but should be made water-tight with cement, so that nothing can reach its interior except water that has been filtered through dense beds of unpolluted ground below. If these precautions are neglected, the best and deepest well may become continually contaminated by infiltration from the surrounding surface. This impure water, even when not used for family drinking, is sometimes supplied to cows, or used for washing dairy pans, or employed in diluting milk for the market, and there are many known cases in which disease has thus been disseminated. Thus, an epidemic of typhoid fever in Cambridge, Mass., was definitely traced to a dairy which supplied the victims with milk. Upon investigation it was found that a short time before there had been a typhoid patient in the farmhouse, and that the well from which water was taken to wash the milk pans had become contaminated with the specific poison brought into it from the surrounding drainage. All suspected water should be thoroughly boiled before using it to drink. Some physicians insist that the boiling should continue for one or two hours in order entirely to destroy the bacterial germs. The heaviness and insipidity incident to boiled water may be somewhat relieved by afterward filtering it. Filtering, of itself, however, will do little toward ridding the water of microbes, which are much too minute to be arrested by the ordinary apparatus.--When journeying, where one must often take a hasty meal at a railway station, drink hot water in preference to cold. A convenient portable filter may be arranged with a bottle of powdered charcoal, and a piece of filtering paper. A traveler by briskly stirring a tablespoonful of the charcoal into a pint of water, allowing it to stand five or ten minutes, and then filtering it through the paper, may venture to relieve his thirst in almost any part of the country. _Water an Absorbent of Foul Gases_.--If a pitcher of water be left uncovered in an occupied apartment for only a few hours, it will become foul from the absorption of the respired and perspired gases in the room. The colder the water, the greater the capacity to contain these gases. Water kept in a room over night is therefore unfit for drinking, and should not be used even to brush the teeth or to gargle in the throat. _Impure Ice, a Breeder of Disease_.--We generally take the purity of our ice for granted, and, like the alligator in the bayou, close our mouths and swallow it. In the country, I have seen during the ice- harvesting season, wagon after wagon passing me on the road, laden with ice that had been collected from canals, rivers, and streams receiving sewerage, and from ponds that are in the summer time reeking with slime, and often offensive from the quantity of decomposed vegetable and animal matter brought in by the washing from the meadow. These streams would be shunned as a source of water supply. Should you interview a native regarding the slimy mud puddle before you, called Mr. So-and-so's private "ice pond," he would say that "in winter it is much better, and when frozen, you know, it makes fine ice," presenting that popular though ignorant belief that while in the act of crystallizing, water rids itself of all its injurious qualities, however offensive it may be in its liquid state. Unfortunately, there is enough truth in the current idea of the elimination of noxious and foreign matter during the process of freezing to give color to the popular belief, but not enough to make it a safe reliance; therefore all means should be used to enlighten the public regarding this subject. Experiment has shown that freezing produces little change or effect in overcoming the poisonous influences, and ice has often served as a vehicle to convey the germs of typhoid and other low forms of fever. Pure ice can be procured only from water free from impurities, and ice for domestic or surgical purposes should never be collected from ponds or streams which contain animal or vegetable refuse, or stagnant and muddy material.--_Journal of Reconstructives, Oct., 1887_. THE GLANDULAR COAT OF THE STOMACH, AND HOW IT WEEPS (p. l62).--While the food is thus being continually moved about, it is at the same time subjected to the action of the chemical sac. This is, as we have said, a glandular sac. It is of some thickness, and is made of little glands bound up together with that stringy fibrous packing material which anatomists call _connective tissue_. If we were to imagine many gross of small India-rubber vials all placed side by side, and bound together with hay or straw into a great mat, and the mat rolled up into a sac, with all the mouths of the vials turned inward, we should have a large and coarse, but tolerably fair image of the glandular coat of the stomach. Each vial would then represent one of the glands of this coat, one of the gastric or peptic glands, as they are called. Each gland, however, is not always a simple tube, but is often branched at the bottom end, and all of them are lined, except just at their mouths, with large rounded bodies, which not unfrequently almost choke up their cavity. FIG. 72. [Illustration: BRANCHED GASTRIC GLAND a. _The peptic cells._ b. _The inert cells._] The rounded masses, or cells, as they are called, in the interior of each gland, form the really active part of the apparatus. Each cell is a little laboratory, which concocts out of the material brought to it or near it by the blood a certain potent, biting fluid, and is hence called a peptic or digestive cell. Each cell is born at the bottom of the tube, and in process of time travels upward toward the mouth. When it reaches the mouth, it bursts, and pours into the stomach the fluid it has elaborated, or perhaps may give it out without bursting, while it is still within its tube. In those cases in which it has been possible to look in upon the stomach while at work (as in the famous case of Alexis St. Martin), and where the orifices of the tiny glands (for though we have compared them to bottles, they are exceedingly small) appear like little dots, tears were seen to start at the mouths of the glands, gather into drops, and finally trickle down into the lowest part of the stomach. The stomach, as it were, weeps, and indeed the weeping of tears is just such another effect of glandular activity--only ordinary tears form a mild and, chemically speaking, impotent fluid; while the fluid which the tears of the stomach weep--the _gastric juice_--is a sharp, piercing water of excessive chemical power.--Hinton. POISONOUS MILK, CHEESE, AND ICE CREAM (p. l69).--In late years there have been many cases of poisoning by ice cream, cheese, and milk. The poisonous principle sometimes developed in these articles of food has been made a subject of special investigation, and it has been found to be due to natural causes. Dr. Vaughan, of Michigan, after spending several months in experimenting upon samples of twelve different cheeses, which had caused three hundred cases of poisoning, finally succeeded in isolating certain poison crystals, which he calls _Tyrotoxicon_. He says: "A few drops of an aqueous solution of these crystals placed upon the tongue produces all the symptoms observed in those who had been made sick by eating of the cheese. This was tried repeatedly upon myself, and upon some of my students who kindly offered themselves for experimentation." Dr. Vaughan afterward procured the poison crystals from milk which had stood some months in a closed bottle, and also from a sample of ice cream by which eighteen persons had been made ill. It was learned in the latter case that the custard, of which the ice cream was made, had been allowed to stand in a foul atmosphere for two hours before it was frozen. By placing small bits of this poisonous cream in good milk, and allowing it to stand twenty-four hours, the whole became vitiated. This proved that the poison is due to the growth of some ferment. In the autumn of 1886, many persons in different hotels at Long Branch were poisoned by milk obtained from a certain milkman. In this case it was found that the cows were milked at noon, the warm milk being immediately placed in cans and carted eight miles during the warmest part of the day, in a very hot month. In June, 1887, nineteen persons in New York city were similarly poisoned by milk which also came from one dairy. Many of these persons had narrow escapes from death. These, and many other like instances, teach us the importance of the greatest care in every detail of milk handling. A little dried milk formed along the seam of a tin pail, or any similar lodging place, may be the starting point of poison generation. A month after his first experiments with the ice cream mentioned above, Dr. Vaughan put small pieces of the dried custard in pans of milk, and afterward made custard from this milk. This yielded tyrotoxicon as before, showing the tenacious vitality of the poison, and also explaining the fact that the precise cause of poisoning is in many cases so difficult to trace. FISH AS FOOD (p. 169).--It is not desirable that fish should be the sole kind of nitrogenous food eaten by any nation; and even if milk and eggs be added thereto, the vigor of such a people will not be equal to that of flesh-eating nations. At the same time, the value of fish as a part of a dietary is indicated by the larger proportion of phosphorus which it contains, and which renders it especially fitted for the use of those who perform much brain work, or who are the victims of much anxiety and distress.--EDWARD SMITH, _in "Foods_." For the mentally exhausted, the worried, the "nervous," and the distressed in mind, fish is not simply a food; it acts as physic. The brain is nourished by it, the "nerves"--to use the term in its popular sense--are "quieted"; the mind grows stronger, the temper less irritable, and the whole being healthier and happier when fish is substituted for butcher's meat....I find persons who are greatly excited, even to the extent of seeking to do violence to themselves or to those around them, who can not sleep, and who are in an agony of irritability, become composed and contented when fed almost exclusively on fish. In such cases I have withdrawn butter, milk, eggs, and all the varieties of warm-blooded animal food; and, carefully noting the weight and strength, I find no diminution of either, while fish is supplied in such quantities as fully to satisfy the appetite.--J. MORTIMER GRANVILLE, M.D., "_Fish as Food and Physic_." COFFEE AND TEA (p. 170).--Besides the alkaloid _Caffeine_ which coffee contains, it also develops, in roasting, a volatile oil called Caffeone, to which is due its characteristic aroma. The main effects of coffee are due to both the caffeine and the caffeone, which are antagonistic, though not contemporaneous, in action. The volatile oil reduces arterial tension, allows a brisker flow of blood, and so increases the rapidity of the heart's action. It also acts upon the brain, and intellectual faculties in general; keeps one awake, and his mind clear. Caffeine, on the other hand, like digitalis, produces a high arterial tension, and slows the heart beat. It exerts its chief effect upon the spinal cord, to which, like strychnia, it is an excitant. The shaking hand of the inveterate coffee drinker is caused by caffeine. Thus a cup of coffee produces on the drinker a double effect,--of the oil and the alkaloid; the former sooner and transient, the latter later and lasting....Coffee is not in itself nutritious to any marked degree; but it saves food, and also maintains life, by its exhilarating effect upon the nervous system. It is an excellent antidote to opium, producing the wakefulness that antagonizes the narcotic sleep of the drug; is now and then curative of sick headache, and is one of the standard remedies for certain forms of nausea. To the chemist, _Tea_ is much the same thing as coffee. It contains considerably more tannin, a volatile oil, and an alkaloid (theine) indistinguishable from caffeine. That the injurious effects of overdoses are due as much to the volatile oil as to the alkaloid, is shown by the fact that tea packers are made ill by long breathing of air filled with it, and that tea tasters in China, who avoid swallowing the infusion, can endure their trade but a few years, and leave the country with shattered nerves. Probably every one numbers among his friends women who are actual slaves of the tea habit, and who would find tea as hard to forsake as men find tobacco. It is not unlikely that the functional cardiac disorder, often spoken of as the "tobacco heart," due to nervous derangement, and accompanied by palpitation and pain in the cardiac region, is more often due to tea than tobacco. In fact, the disorders induced by excessive tea drinking have been grasped as a special disease, to which has been given the name of _Theism_. This includes a train of symptoms, usually progressive, loss of appetite, pain after meals, headache, constipation, palpitation, cardiac distress, hysterical manifestations, dizziness, and paresis.--DR. MAURICE D. CLARKE, _Popular Science News_. Tea drinkers, as a rule, express doubts as regards the correctness of alleged poisonous properties of tea. Numerous instances of individuals of this class have been noticed who were themselves suffering from tea poisoning. Their nerves were in a deplorably abnormal condition, the heart and brain were functionally disturbed, and the sleep less in quantity and less refreshing than it should be....One's opinion of the physical disturbances which may be caused by rum, tobacco, or tea, are not worth much, when the opinion comes from a victim of the excessive use of these agents. The tannin found in tea does not differ from that found in oak and other barks which the tanners use to convert the raw hides of animals into leather. It is a powerful astringent, which accounts for some of the peculiar physical evils to which confirmed tea drinkers are subject. _Theine_ does not differ essentially from _Cocaine_ (see p. 223). They both produce exaltation of the nervous system and increased powers of physical endurance. The brain is largely influenced in its functions, and long periods of wakefulness are induced. Continued use of strong infusions of either coca or tea result in great disturbance of nervous centers and functional offices, and either will produce fatal results by persistent use of inordinate quantities. A cup of tea as served at tea tables contains usually only a trace of the alkaloidal principle, but infinitesimal quantities are capable of exerting baneful effects upon some tea drinkers....Poisons act in a variety of ways, some slowly, and without producing pain; others act violently, and with speedy, fatal results. Inasmuch as we do not observe a very large number of clearly proved cases of acute poisoning by tea, we must conclude that it is characteristically a slow poison, and also that its influence is unlike in different individuals....Four or six cups of tea, however, taken during each twenty-four hours, will in time produce tea poisoning, and greater or less evil effects. Tea is well enough, when its use is kept under absolute, intelligent control; but if it becomes master in any case, then it must be promptly abandoned, for danger attends the intemperate tea drinker every hour of his life. Those advanced in life crave its stimulating effects, and it is well for them to use it in moderation; but the young should abstain from it entirely.--_Abridged from "Tea Poisoning," by_ DR. NICHOLS, _in Popular Science News, December, 1887_. CAUSES AND EFFECTS OF INDIGESTION (p. l72).--When a light breakfast is eaten, a solid meal is requisite in the middle of the day. If the digestive organs are left too long unemployed, they secrete an excess of mucus, which greatly interferes with their normal functions. One meal has a direct influence on the next; and a poor breakfast leaves the stomach over-active for dinner. This is the secret of much excess in eating. The point to bear in mind is that not to eat a sufficiency at one meal makes you too hungry for the next; and that when you are too hungry, you are apt to overload the stomach, and to give the gastric juices more to do than they have the power to perform. To eat too often, and to eat irregularly, are other sources of indigestion. People who dine at uncertain hours, and eat one meal too quickly on the last, must expect the stomach to retaliate in the long run. A very fruitful cause of dyspepsia is imperfect mastication. We remember one old gentleman who used always to warn young people on this point by saying: "Remember you have no teeth in your stomach." Nervous people nearly always eat fast, and as nearly always are the victims of nervous irritability, produced by dyspepsia....To sit much in a stooping posture interferes with the stomach's action. Well-marked dyspepsia has been traced to sitting immediately after dinner in a low armchair, so that the body was curved forward, and the stomach compressed.... The skin, core, and kernels of fruit should be avoided. Some people are not able to digest raw apples; and dyspepsia has been sometimes greatly aggravated by eating pears. The latter fruit, in its ripest state, contains an abundance of gritty material, which, as it can not be separated in the mouth, on being swallowed irritates the mucous membrane.... Of food itself, bear in mind that hot meat is more digestible than cold; the flesh of full-grown animals than that of young ones; that land birds are more digestible than waterfowl; wild animals than domestic ones; and that in game, newly killed birds are easier of digestion than those which have been kept a long time.--_Hints to Dyspeptics, Chambers's Journal_. HOW FOOD DEVELOPS ENERGY (p. 173).--It may appear strange that the small amount of food we eat should suffice to carry our large and bulky bodies through all the varied movement of the day. But this difficulty disappears at once, when we recollect how large an amount of dormant energy can be laid by in a very small piece of matter. A lump of coal no bigger than one's fist, if judiciously employed, will suffice to keep a small toy engine at work for a considerable time. Now, our food is matter containing large amounts of dormant energy, and our bodies are engines so constructed as to utilize all the energy to the best advantage. A single gramme of beef fat if completely burned (that is, if every atom unites with oxygen), is capable of developing more than 9,000 heat units; and each heat unit, if employed to perform mechanical work, is capable of lifting a weight of one gramme to a height of 424 meters; or, what comes to the same thing, 424 grammes to a height of one meter. Accordingly, the energy contained in one gramme of beef, and the oxygen with which it unites, would be sufficient to raise the little bit of fat itself to a height of 3,816 kilometers, or almost as high as the distance from London to New York.-- GRANT ALLEN _in "Why do we Eat our Dinner_?" _Danger of Too High Pressure_.--A prudent fire engineer, when his water hose is old and weak, would not try to force as much water as he could into it. No; to prevent a rupture he would work it at a low pressure. But men seldom think of carrying out the same simple mechanical principle when there is reason to believe that the vessels of the brain are getting weak and brittle. They eat and drink just as much as they feel inclined to, and sometimes a little more. With a good digestion, nearly all they consume is converted into blood, to the yet further distention of vessels already over-distended. This high-pressure style of living produces high-pressure results. Its effects were painfully illustrated by the death of Charles Dickens. The brain work he performed was immense; he lived generously, taking his wine as he did his meat, with a liberal hand. He disregarded the signs of structural decay, forcing his reluctant brain to do what it had once done with spontaneous ease, until all at once, under a greater tension than ordinary, a weak vessel gave way, flooding the brain with blood.--J. R. BLACK, M.D., _in "Apoplexy," Popular Science Monthly, April, 1875_. _Evils of Gluttony_.--"Is it not strange," says Dr. Hunt, "how people, even the most considerate, will trifle with their stomachs? Many a person seems to prefer taking medicine to avoiding it by a proper regulation of the appetite. You may stuff the stomach to the full, year after year, but as sure as effects follow causes, so sure will you reap the accumulating penalty." A physician of extensive practice declares that he has never lived through a Christmas or Thanksgiving without frequently being consulted for ailments produced by excessive eating. He says: "It would seem as if multitudes thought they had a gluttonous license once a year, and that the most appropriate method of expressing gratitude, was by stuffing the stomach. Excessive eating produces scrofula. Surfeiting among children results in mental stupidity and unmanageable temper....I am acquainted with a family, in which about the average amount of stuffing is indulged. To my expostulations, the mother has replied: "I may not be able to give my children as much education as some folks, and I may not be able to give them any property, but as long as we can get it, they shall have what they want to eat. I have spoken of their black teeth, bad breath, eruptions, and frequent sickness. "Yes," she has replied, "I know all that, but would you have me stop them before their appetites are half satisfied, and tell them, 'there, that is all you can have'? No; as long as I can get it, my children shall have enough to eat; it never shall be said that I have starved them." This indulgence of children to the full extent of their undiscriminating appetites is extreme folly and genuine unkindness. Pampered with a variety of dishes, they eat enormously, which engenders a craving for another large meal, and so on--their youthful and elastic constitutions enabling them to bear the excess without immediate serious injury. Let them be confined to one or two plain dishes at a meal, and the quantity be determined for them; it will then be found that a growing child does not need to be stuffed, and that his appetite will soon become reasonable; and if the food be plain, and mostly or entirely vegetable, it will soon be observed that the child's teeth are whiter, its breath sweeter, its skin clearer, its tongue cleaner, its eyes brighter, its sleep quieter, its brains sharper, and its temper more amiable. There are few changes in the management of children which would prove so beneficial as that from the present mode of cramming with a multitude of rich foods, to a plain vegetable diet, eaten in regular and moderate quantities.--DIO LEWIS, _in Weak Lungs, and How to Make them Strong_. REGULAR PHYSICAL HABITS (p. 177).--Constipation lies at the root of a host of chronic ailments, which seem especially to beset American women. Impaired blood, nervous excitability, sick headaches, mental depression, sleeplessness, and a long train of untold sufferings may be directly traced to this physical sin. We say _sin_, for in the large majority of instances this habit may be prevented; or, if already formed, may, by proper attention, be cured. The principal causes which lead to this deplorable state of the system are: 1. Errors in Food. 2. Errors in Exercise. 3. Inattention to Nature's laws. _Errors in Food_ have much to do with the evil in question. Our diet is, in general, too concentrated. We indulge ourselves with animal food two or three times a day, accompanying it with spices, condiments, greasy gravies, fine wheat bread, and a sparse amount of vegetables. We wind up our dinners with rich and heavy pastry, and our luncheons or our suppers with sugared sweetmeats and that indigestible compound often offered under the name of cake. A few cups of strong tea intensify the error. Coffee has a less astringent effect, and therefore can not be so severely arraigned for this particular consequence. When we think what delicious meals can be enjoyed from any of the cereals, well cooked, and taken with milk or cream, bread from unbolted flour, plenty of unsugared fruit, and pure rain or spring water, filtered and cooled or taken hot, with or without milk, we wonder that so many people consent day after day to use greasy pork, fried steaks, fried potatoes, hot biscuit, and in many cases poorly made coffee and tea. These are the people who make up the grand army of sallow- faced sufferers upon which the venders of patent pills and nauseous compounds thrive. A wise mother will not allow mere culinary convenience to take precedence of the requirements of health. She will study the peculiar physical needs of each one of her children, that she may provide for each the food best suited to his or her constitution. This is not a difficult matter. "Water, not only by itself, but in some of its combinations," says Dr. Oswald, "is an effective aperient; in watermelons, and whey, for instance, but still more in conjunction with a dish of peas, or beans. No constipation can long withstand the suasion of a dose of pea soup, or baked beans, flavored with a modicum of brown butter, and glorified with a cup of cold spring water. Moreover, the aperient effect thus produced is not followed by an astringent reaction, as in the case of drugs,--the cure, once effected, is permanent." _Errors in Exercise_ may lie in two directions, and overexertion, viz., exercise carried to the point of nervous exhaustion, is as mischievous in its effect as is the other extreme. A too long walk, for instance, may cause the very evil it is intended to cure. As a rule, however, sedentary habits are chargeable with the greater share of influence in this unhappy state of the system. Light gymnastics within doors, a brisk walk or horseback ride without, both taken in garments suspended from the shoulders, and devoid of all constriction so that the abdominal viscera can partake in the general movement of the body, are advisable. For invalids or those incapacitated for active exercise, friction or massage treatment daily, including a vigorous kneading of the abdomen, or a relaxation of the entire muscles of the body with especial thought directed to the desired result, are often of great service. _Inattention to Physical Laws_ is perhaps the prime culprit. Nature always inclines to regularity, and when we do not respect her dictates, we invite the retribution which, sooner or later, she invariably inflicts. The elimination of waste from the system is an imperative necessity, and whenever it is thwarted, evil must and will follow. Aside from the avoidance of positive discomforts, suffering, and disease, there is the not unimportant consideration of bodily elasticity and a fine complexion. Let every young woman who would possess and retain a fair, delicate complexion, remember that the most important factor in its formation and retention is a clean system. Proper diet, plenty of fruits, plenty of wholesome drink, enough exercise to send the blood pleasurably bounding through the veins, followed up and enforced by prompt recognition of the immutable laws of Health in this as well as all other organic functions, will soon work a reform that could not be so successfully effected by all the drugs in Christendom.--E. B. S. THE NERVOUS SYSTEM. EFFECT OF VIOLENT PASSIONS UPON HEALTH (p. 202).--The man who is given to outbursts of anger is sure to experience a rapid change of the physical organs, in case he does not die in a fit of rage. Death under such circumstances is of frequent occurrence. Sylla, Valentinian, Nerva, Wenceslas, and Isabeau of Bavaria, all died in consequence of an access of passion. The medical annals of our own time recount many instances of fatal effects following the violent brain disturbance caused by anger. The symptoms usually are pulmonary and cerebral congestions. Still such fatal accidents as these are exceptional; as a rule, the passions of hate and anger deteriorate the constitution by slow, but sure degrees. How, then, do we explain those morbid phenomena which have their origin in misplaced affection, in disappointed ambition, in hatred, or in anger, and which culminate either in serious chronic maladies, or in death or suicide? They all seem to start from an impairment of the cerebro-spinal centers. The continual excitation of these by ever-present emotions determines a paralysis of the central nerve substance, and thus affects its connections with the nerves extending out to the various organs. These nerves next degenerate by degrees, and soon the great functions are compromised. The heart and the lungs cease to act with their normal rhythm, the circulation grows irregular and languishing. Appetite disappears, the amount of carbonic acid exhaled decreases, and the hair grows white, owing to the interruption of the pigmentary secretion. This general disturbance in nutrition and secretion is attended with a fall of the body's temperature and anæmia. The flesh dries up and the organism becomes less and less capable of resisting morbific influences. At the same time, in consequence of the reaction of all these disturbances on the brain, the psychic faculties become dull or perverted, and the patient falls into a decline more or less complicated and aggravated by grave symptoms. Under these conditions he dies or makes away with himself. Two organs, the stomach and the liver, are often affected in a peculiar and characteristic way in the course of this pathological evolution. The modifications produced in the innervation, under the influence of cephalic excitement, cause a disturbance of the blood circulation in the liver. This disturbance is of such a nature that the bile, now secreted in larger quantity, is resorbed into the blood instead of passing into the biliary vesicle. Then appears what we call jaundice. The skin becomes pale, then yellow, owing to the presence in the blood of the coloring matter of the bile. This change in the liver is usually developed slowly: sometimes, however, jaundice makes its appearance suddenly. Villeneuve mentions the case of two youths who brought a discussion to an end by grasping their swords; suddenly one of them turned yellow, and the other, alarmed at this transformation, dropped his weapon. The same author speaks of a priest who became jaundiced on seeing a mad dog jump at him. Whatever may be said of these cases, we must reckon painful affections of the soul among the efficient causes of chronic diseases of the liver. The digestion, says the author of a work published some years ago, is completely subjected to the influence of the moral and intellectual state. When the brain is wearied by the passions, appetite and digestion are almost gone....There is nowhere perfect health, save when the passions are well regulated, harmonized, and equipoised. Moral temperance is as indispensable to a calm and tranquil life as physiological temperance....If it is your desire that your circulatory, respiratory, and digestive functions should be discharged properly, normally, if you want your appetite to be good, your sleep sound, your humor equable, avoid all emotions that are overstrong, all pleasures that are too intense, and meet the inevitable sorrows and the cruel agonies of life with a firm and resigned soul. Ever have some occupation to employ and divert your mind, and to make it proof against the temptations of want or of desire. Thus will you attain the term of life without overmuch disquiet and affliction.--FERNAND PAPILLON, _in the Revue des Deux Mondes_. BRAIN WORK, OVERWORK, AND WORRY (p. 205).--_Overstimulation of the Brain in Childhood_.--Most civilized communities have enacted laws against the employment of children in severe physical labor. This is well enough, for the muscles of young persons are tender and weak, and not, therefore, adapted to the work to which cupidity or ignorance would otherwise subject them. But no such fostering care does the State take of the brains of the young. There are no laws to prevent the undeveloped nervous system being overtasked and brought to disease, or even absolute destruction. Every physician sees cases of the kind, and wonders how parents of intelligence can be so blind to the welfare of their offspring as to force, or even to allow, their brains to be worked to a degree that, in many cases, results in idiocy or death. Only a few months ago I saw for the first time a boy of five years of age, with a large head, a prominent forehead, and all the other signs of mental precocity. He had read the first volume of Bryant's "History of the United States," and was preparing to tackle the other volumes! He read the magazines of the day with as much interest as did his father, and conversed with equal facility on the politics of the period. But a few weeks before I saw him he had begun to walk in his sleep, then chorea had made its appearance, and on the day before he was brought to me he had had a well-marked epileptic paroxysm. Already his mind is weakened --perhaps permanently so. Such cases are not isolated ones. They are continually occurring. The period of early childhood--say up to seven or eight years of age--is that during which the brain and other parts of the nervous system are most actively developing, in order to fit them for the great work before them. It is safe to say that the only instruction given during this time should be that which consists in teaching children how to observe. The perceptive faculties alone should be made the subjects of systematic attempts at development. The child should be taught how to use his senses, and especially how to see, hear, and touch. In this manner, knowledge would be acquired in the way that is preeminently the natural way, and ample food would be furnished for the child's reflective powers.--DK. WM. A. HAMMOND, _Popular Science Monthly, November, 1884_. _Reserve Force_.--The part which "a stock of energy" plays in brain work can scarcely be exaggerated. Reserves are of high moment everywhere in the animal economy, and the reserve of mental force is in a practical sense more important than any other....Without this reserve, healthy brain work is impossible. Pain, hunger, anxiety, and a sense of mind weariness, are warning tokens of exhaustion. When the laborious worker, overcome with fatigue, "rouses" himself with alcohol, coffee, tea, or any other agent which may chance to suit him, he does not add a unit of force to his stock of energy; he simply narcotizes the sense of weariness, and, the guard being drugged, he appropriates the reserve....Meanwhile, the effort to work becomes daily more laborious, the task of fixing the attention grows increasingly difficult, thoughts wander, memory fails, the reasoning power is enfeebled; physical nerve or brain disturbance may supervene, and the crash will then come suddenly, unexpected by on-lookers, perhaps unperceived by the sufferer himself. _Overwork and Worry_.--The miseries of "overwork," pure and simple, are few and comparatively insignificant....The natural safeguards are so well fitted for their task that neither body nor mind is exposed to the peril of serious exhaustion so long as their functions are duly performed. Overwork is _impossible_ so long as the effort made is natural....There is then no excuse for idleness in the pretense of possible injury. If insane asylums were searched for the victims of "overwork," they would nearly all be found to have fallen a prey to "worry," or to the degeneracy which results from lack of purpose in life, and of steady employment ....The cause or condition which most commonly exposes the reserve of mental energy to loss and injury is worry. When a strong and active mind breaks down suddenly in the midst of business, it is usually worn out by this cause rather than by the other....Work in the teeth of worry is fraught with peril. The unhappy victim is ever on the verge of a catastrophe; if he escape, the marvel is not at his strength of intellect so much as at his good fortune. Worry is disorder, however induced, and disorderly work is abhorred by the laws of nature, which leave it wholly without remedy. The pernicious system of _Cram_ slays its thousands, because uneducated, undeveloped, inelastic intellects are burdened and strained with information adroitly deposited in the memory,--as an expert valet packs a portmanteau, with the articles likely to be first wanted on the top. _Desultory occupation_, mere play with objects of which the true interest is not appreciated, ruins a still larger number. But _worry_, that bane of brain work and mental energy, counts its victims by tens of thousands.--DR. J. MORTIMER GRANVILLE, _in "Worry," Nineteenth Century_. SLEEP (p. 206).--_Some Curiosities of Sleep_.--One of the most refined and exquisite methods of torture is long continued deprivation of sleep. The demand for unconscious rest is so imperious that nature will accommodate itself to the most unfavorable surrounding conditions. Thus, in forced marches, regiments have been known to sleep while walking; men have slept soundly in the saddle; and persons will sometimes sleep during the din of battle. It is remarkable how noises to which we have been accustomed will fail to disturb our natural rest. Those who have been long habituated to the endless noise of a crowded city frequently find difficulty in sleeping in the oppressive stillness of the country. Prolonged exposure to intense cold induces excessive somnolence, and if this be induced, the sleep passes into stupor, the power of resistance to cold becomes rapidly diminished, and death is the inevitable result. Intense heat often produces drowsiness, but, as is well known, is not favorable to natural sleep....It is difficult to determine with exactness the phenomena of sleep that are absolutely physiological, and to separate those that are slightly abnormal. We can not assert, for example, that a dreamless sleep is the only normal condition of repose of the system; nor can we determine what dreams are due to previous trains of thought, or to such impressions from the external world received during sleep as are purely physiological, and what are due to abnormal nervous influence, disordered digestion, etc. The most remarkable experiments upon the production of dreams of a definite character, by subjecting a person during sleep to peculiar influences, are those of Maury. The hallucinations produced in this way are called hypnagogic (from its derivation this term is properly applied only to phenomena observed at the instant when we fall asleep, or when we are imperfectly awakened, and not to the period of most perfect repose), and they occur when the subject is not in a condition favorable to sound sleep. The experiments made by Maury upon himself are so curious and interesting that we quote the most striking of them in full. _First Observation_.--I am tickled with a feather successively on the lips and inside of the nostrils. I dream that I am subjected to a horrible punishment, that a mask of pitch is applied to my face, and then roughly torn off, tearing the skin of the lip, the nose, and the face. _Second Observation_.--A pair of pincers is held at a little distance from my ear, and rubbed with steel scissors. I dream that I hear the ringing of bells; this soon becomes a tocsin, and I imagine myself in the days of June, 1848. (The time of the French Revolution.) _Third Observation_.--I am caused to inhale Cologne water. I dream I am in a perfumer's shop; the idea of perfumes doubtless awakens the idea of the East; I am in Cairo, in the shop of Jean Farina.... _Fifth Observation_.--I am slightly pinched on the nape of the neck. I dream that a blister is applied, which recalls to my mind a physician who had treated me in infancy. _Seventh Observation_....The words Azar, Castor, Leonore, were pronounced in my ear; on awaking I recollected that I had heard the last two words, which I attributed to one of the persons who had conversed with me in my dream.--FLINT'S _Physiology of Man_. The transition stage between the dream simple and the dream acted is witnessed in the spasmodic movements which a vivid dream produces in the limbs or person of the sleeper. The dreamer engages in a fierce struggle, and twitchings of his legs and arms indicate the feeble response of body to the promptings of mind removed from its wonted power over the frame. Even the dog, as he sleeps, apparently dreams of the chase, and gives vent to his sensations by the short, sharp bark, or sniffs the air, and starts in his slumber as if in response to the activity with which, in his dreaming, he is hurrying along after the object of pursuit....Persons have been known to swim for a considerable time in the somnambulistic state without waking at the termination of their journey; others have safely descended the shaft of a mine, while some have ascended steep cliffs, and have returned home in safety during a prolonged sleep vigil. (See p. 204.)--DR. ANDREW WILSON, F.R.S.E., _What Dreams are Made of_. _Sleep and Conscience_.--Edward Everett Hale says: Never go to bed in any danger of being hungry. People are kept awake by hunger quite as much as by a bad conscience. Remembering that sleep is the essential force which starts the whole system, decline tea or coffee within the last six hours before going to bed. Avoid all mathematics or intricate study of any sort in the last six hours. This is the stuff dreams are made of, and hot heads, and the nuisances of waking hours. Keep your conscience clear. Remember that because the work of life is infinite, you can not do the whole of it in any limited period of time, and that therefore you may just as well leave off in one place as another. _The Art of Rising Early_.--The proper time to rise is when sleep ends. Dozing should not be allowed. True sleep is the aggregate of sleeps, or is a state consisting in the sleeping or rest of all the several parts of the organism. Sometimes one and at other times another part of the body, as a whole, may be the least fatigued, and so the first to awake; or the most exhausted, and therefore the most difficult to arouse. The secret of good sleep is, the physiological conditions of rest being established, so to work and weary the several parts of the organism as to give them a proportionately equal need of rest at the same moment. To wake early, and feel ready to rise, a fair and equal start of the sleepers should be secured; and the wise self-manager should not allow a drowsy feeling of unconsciousness, or weary senses, or an exhausted muscular system, to beguile him into the folly of going to sleep again when once he has been aroused. After a few days of self-discipline, the man who resolves not to doze, that is, not to allow some sleepy part of his body to keep him in bed after his brain has once awakened, will find himself, without knowing why, an early riser. INFLUENCE OF SUNLIGHT (p. 207).--Light is an essential element in producing the grand phenomena of life, though its action is ill understood. Where there is light there is life, and any deprivation of this principle is rapidly followed by disease of the animal frame, and the destruction of the mental faculties. We have proof of this in the squalor of those whose necessities compel them to labor in places to which the blessings of sunshine never penetrate, as in our coal mines, where men having everything necessary for health, except light, exhibit a singularly unhealthy appearance. The state of fatuity and wretchedness to which those individuals have been reduced, who have been subjected for years to incarceration in dark dungeons, may be referred to the same deprivation.-- ROBERT HUNT, _Poetry of Science_. _Effect of Dungeon Life_.--"You can not imagine, Mr. Kennan," said a condemned revolutionist to me in Siberia, "the misery of prolonged confinement in a casemate of the fortress under what are known as dungeon conditions. My casemate was sometimes cold, generally damp, and always gloomy. Day after day, week after week, month after month, I lay there in solitude, hearing no sound save that of the high-pitched, melancholy bells of the fortress cathedral, which slowly chimed the quarter hours, and which always seemed to say: 'Here thou liest--lie here still.' I had absolutely nothing to do except to pace my cell from corner to corner, and think. For a long time I used to talk to myself in a whisper; to repeat softly everything in the shape of literature that I could remember, and to compose speeches which, under certain imagined conditions, I would deliver; but I finally ceased to have energy enough to do even this, and used to sit for hours in a sort of stupor, in which, so far as I can now remember, I was not conscious of thinking at all. Before the end of the first year, I grew so weak, mentally and physically, that I began to forget words. I knew what ideas I desired to express, but some of the words that I needed had gone from me, and it was with the greatest difficulty that I could recover them. It seemed sometimes as if my own language were a strange one to me, or one which, from long disuse, I had forgotten. I greatly feared insanity, and my apprehension was increased by the fact that two or three of my comrades in cells on the same corridor were either insane or subject to hallucinations; and I was often roused at night and thrown into a violent chill of nervous excitement by their hysterical weeping, their cries to the guard to come and take away somebody, or something which they imagined they saw, or their groans and entreaties when, in cases of violent delirium, they were strapped to their beds by the _gendarmes_."--GEORGE KENNAN, _in Russian State Prisoners, The Century, March, 1888_. THE GROWTH AND POWER OF POISON HABITS (p. 218).--In order to distinguish a poison stimulant from a harmless and nutritive substance, Nature has furnished us three infallible tests: 1. The first taste of every poison is either insipid or repulsive. 2. The persistent obtrusion of the noxious substance changes that aversion into a specific craving. 3. The more or less pleasurable excitement produced by a gratification of that craving is always followed by a depressing reaction.... One radical fallacy identifies the stimulant habit in all its disguises: its victims mistake a process of irritation for one of invigoration.... Sooner or later the tonic is sure to pall while the morbid craving remains, and forces its victims either to increase the quantity of the wonted stimulant, or else to resort to a stronger poison. A boy begins with ginger beer and ends in ginger rum; the medical "tonic" delusion progresses from malt extract to Mumford's Elixir; and the nicotine habit once introduced, the alcohol habit often follows. The tendency of every stimulant habit is toward a stronger tonic....We have found that the road to the rum shop is paved with "mild stimulants," and that every bottle of medical bitters is apt to get the vender a permanent customer. We have found that cider and mild ale lead to strong ale, to lager beer, and finally to rum, and the truth at last dawns upon us that the only safe, consistent, and effective plan is Total Abstinence from all Poisons. ...More than the hunger after bread, more than the frenzy of love or hatred, the poison hunger overpowers every other instinct, even the fear of death. Dr. Isaac Jennings has illustrated this by the following example: A clergyman of his acquaintance attempted to dissuade a young man of great promise from habits of intemperance. "Hear me first a few words," said the young man, "and then you may proceed. I am sensible that an indulgence in this habit will lead to the loss of property, the loss of reputation and domestic happiness, to premature death, and to the irretrievable loss of my immortal soul; and now, with all this conviction resting firmly on my mind and flashing over my conscience like lightning, if I still continue to drink, do you suppose anything you can say will deter me from the practice?" ...Ignorance is a chief cause of intemperance. The seductions of vice would not mislead so many of our young men if they could realize the significance of their mistake. There is still a lingering belief that, with due precaution against excess and adulteration, a dram drinker might "get ahead" of Nature, and, as it were, trick her out of some extra enjoyment. There is no hope of a radical reform till intelligent people have realized the fact that this "trick" is in every instance a losing game, entailing penalties which far outweigh the pleasures that the novice may mistake for enjoyments. For the depression of the vital energy increases with every repetition of the stimulating process, and in a year after the first dose all the "grateful and exhilarating tonics" of our professional poison venders can not restore the vigor, the courage, and the cheerfulness which the mere consciousness of perfect health imparts to the total abstainer. A great plurality of all beginners underrate the difficulty of controlling the cravings of a morbid appetite. They remember that their natural inclinations at first opposed, rather than encouraged, the indulgence; and they feel that at the present stage of its development they could abjure the passion without difficulty. But they overlook the fact that the moral power of resistance decreases with each repetition of the dose, and that the time will come when only the practical impossibility of procuring their wonted tipple will enable them to keep their pledge of total abstinence. It is true that, by the exercise of a constant self-restraint, a person of great will force may resist the progressive tendency of the poison habit and confine himself for years to a single cigar or a single bottle of wine per day....But the attempt to resist that bias will overtask the strength of most individuals. According to the allegory of the Grecian myth, the car of Bacchus was drawn by tigers; and it is a significant circumstance that war, famine, and pestilence have so often been the forerunners of veritable alcohol epidemics....The explanation is that, after the stimulant habit has once been initiated, every unusual depression of mental or physical vigor calls for an increased application of the accustomed method of relief....Nations who are addicted to the worship of a poison god will use his temple as a place of refuge from every calamity; and children whose petty ailments have been palliated with narcotics, wine, and cordials, will afterward be tempted to drown their greater sorrows in deeper draughts of the same nepenthe.--FELIX L. OSWALD, M.D., _Remedies of Nature, Popular Science Monthly, October and November, 1883_. DANGERS FROM THE USE OF NARCOTICS.--It may seem a paradox, it is a truism, to say that in the value of narcotics lies their peril. Because they have such power for good, because the suffering which they alleviate is in its lighter forms so common, because neuralgia and sleeplessness are ailments as familiar to the present generation as gout, rheumatism, and catarrh were to our grandfathers, therefore the medicines which immediately relieve sleeplessness and neuralgic pain are among the most dangerous possessions, the most subtle temptations of civilized life. Every one of these drugs has, besides its instant and beneficial effect, other and injurious tendencies. The relief which it gives is purchased at a certain price; for, at each repetition of the dose, the immediate relief is lessened or rendered uncertain, while the mischievous influence is enhanced and aggravated; till, when the drug has become a necessity of life it has lost the greater part, if not the whole, of its value, and serves only to satisfy the need which itself alone has created....We read weekly of men and women poisoned by an overdose of some favorite sedative, burned to death or otherwise fatally injured, while insensible from self- administered ether or chloroform....The narcotist keeps chloroform or chloral always at hand, forgetful or ignorant that one sure effect of the first dose is to produce a semistupor more dangerous than actual somnolence. In that semistupor the patient is aware, or fancies, that the dose has failed. The pain that has induced a lady to hold a chloroformed handkerchief under her nostrils returns while her will and her judgment are half paralyzed. She takes the bottle from the table beside her bed, intending to pour an additional supply upon her handkerchief. The unsteady hand perhaps spills a quantity on the sheet, perhaps sinks with the unstoppered bottle under her nostrils, and in a few moments she has inhaled enough utterly to stupefy, if not to kill. The sleepless brain worker also feels that his usual dose of chloral has failed to bring sleep; he is not aware how completely it has stupefied the brain, to which it has not given rest. His judgment is gone, so is his steadiness of hand; and he pours out a second and too often a fatal dose....But the cases that end in a death terrible to the family, though probably involving little or no suffering to the victim himself, are by no means the worst. A life poisoned, paralyzed, rendered worthless for all the uses of intellectual, rational, we might almost say of human existence, is worse for the sufferer himself and for all around him than a quick and painless death; and for one such death there must be twenty, if not a hundred, instances of this worst death in life....The demoralization of the narcotist is not, like that of the drunkard, rapid, violent, and palpable; but gradual, insidious, perceptible at first only to close observers and intimate friends. Here and there we find a constitution upon which opium exerts few or none of its characteristic effects. Such cases are, of course, wholly exceptional; but their very existence is a danger to others, misleading them into the idea that they may dally with the tempter without falling under its yoke, or may fall under that yoke and find it a light one. I doubt, however, whether the most fortunate of its victims would encourage the latter idea; whether there be an opium eater who would not give a limb never to have known what opium slavery means....Besides, no one can be sure, or indeed reasonably hope, that the mischief will be confined to the individual victim. That the children of drunkards are often predisposed to insanity is notorious; that the children of habitual opium eaters inherit an unmistakable taint, whether in a diseased brain, in morbid cravings, or simply in a will too weak to resist temptation, is less notorious, but equally certain.--PERCY GREG, _Narcotics and Stimulants, Contemporary Review_. Thus also in America scarcely a week passes but we see announced in the public prints deaths or suicides resulting from the use of narcotics. Now, it is from tobacco: A Yale College student dies from excessive smoking; another student in the same college, and as a result of the same habit, commits suicide; a third young man is found dead in his bed in New York, from heart disease induced by cigarettes; and so, month by month, and year by year, grows in rapid increase the list of tobacco deaths.--Or, again, it is from opium. A Harvard student with two of his college companions in search of a new sensation, tries opium smoking one fatal night and dies before morning; a woman in Ohio, belonging to a prominent family, dies at the age of thirty-three years, from an overdose of morphine, her body covered with hypodermic scars; another, once the respected wife of a Baptist clergyman, becomes a morphine drunkard, drifts, step by step, into a Central New York Almshouse, and there hangs herself; a third, young, accomplished, and wealthy, falls first a victim to the morphine habit, then to opium smoking, finally becomes the frequenter of a New York opium joint, and so is lost forever to home, friends, and respectability.-- Occasionally it is cocaine, as in the case of the Chicago physician, who, for the purposes of investigation, experiments with this new drug upon himself, his wife, and finally upon his innocent children; the entire family being found unconscious from the effects of the subtle narcotic. These are but solitary instances in an appallingly long list of similar cases, most of which have occurred within the last two years (1887-'88). _Cigarette Smoking_ is chargeable with a growing demoralization and mortality among boys and young men. It is no uncommon sight to see lads of ten years old and under, with the irresponsibility of ignorant childhood, puffing the dangerous cigarette, and thus undermining health and intellect at the very outset of useful existence. Even when told of the near and remote perils thus incurred, they scarcely listen, for do not they see their elders smoke and prosper?--Most of them do not understand that there is more danger to the young than to the old in the tobacco habit, more danger to some constitutions than to others, and more danger in the cigarette than even in the pipe or the cigar. Pause a moment to consider it, boys, when you are tempted to light the clean-looking, paper-covered roll and place it in your mouth. Think of the heated smoke irritating the delicate membrane in your throat, dulling your brain, and vitiating the blood which should be bounding fresh and pure through your veins. Think of the many filthy and diseased mouths from which have been cast away the tobacco refuse, picked up in streets and public places to reappear in the "Cheap and Popular Brand" which looks to you so innocent and so attractive. It is astonishing, indeed, how an otherwise cleanly boy will consent to defile himself with these vile abominations. And yet, I have known lads who--not always with perfect politeness--would fastidiously refuse "hash" at their mother's breakfast table, but who would shortly afterward serenely place one of these unknowable compounds between their lips and walk away with the air of superior manhood! _Of Chloral Hydrate_, Dr. Fothergill remarks: "When this was announced with a flourish of trumpets as a perfectly innocuous narcotic, the sleepless folk hailed its advent with eager acclamation. But a little experience soon demonstrated that the innocuous, harmless drug was far from the boon it was proclaimed. In fact, the impression of its harmlessness was the outcome of ignorance of its properties. Death after death, even among medical men themselves, as well as nonprofessional persons, have already resulted from the use, or rather misuse, of this narcotic agent." _The Bromides_ (of Soda or Potash), also, should be used with caution, and only on the prescription of a conscientious physician. "The bromide of potash," says Percy Greg, "is claimed not to produce sleep by stupefaction, like chloral or opium, but, at least in small doses, to allay the nervous irritability which is often the sole cause of sleeplessness. But in larger quantities and in its ultimate effects, it is scarcely less to be dreaded than chloral." Overdoses of the bromides will produce among other evil effects a peculiar eruption upon the face, which, though generally temporary, is liable to reappear from time to time under certain conditions of the system, and especially upon a subsequent dose, however dilute. _Absinthe_ is a compound of absinthium (the essence of wormwood), various aromatic oils, and alcohol. Absinthium, taken in small doses, induces trembling, stupor, and insensibility; in larger doses, epilepsy. When, therefore, this dangerous essence is added to alcohol, it strengthens its influence to specific disease. Absinthe drinking is recognized in France as such a serious vice that it has been officially prohibited in the army and navy. _Hasheesh_ is a syrup prepared from the leaves and flowers of Indian Hemp. Though its use in this country is comparatively small, instances are not unknown in which reckless or curious persons have fatally experimented with it. As a medicine, it is in limited use, and with results not always satisfactory. It acts in a peculiar manner upon the nervous centers, occasioning that strange condition of the nervous system called catalepsy, in which the limbs of the unconscious patient remain stationary in whatever position they may be placed. After an average dose of hasheesh, the subject becomes the helpless victim of rapidly shifting ideas, a prominent characteristic of which is an entire loss of judgment as to time and place. A larger dose produces hallucinations and delirium, with that distressing sensation of falling through endless space which is induced in some people by opium. [Footnote: In an article entitled "An Overdose of Hasheesh" (_Popular Science Monthly_, February, 1884), Miss MARY A. HUNGERFORD gives a vivid description of a painful experience with this drug, some portion of which is as follows: "Being one of the grand army of sufferers from headache, I took, last summer, by order of my physician, three small daily doses of hasheesh in the hope of holding my intimate enemy in check....I grew to regard the drug as a harmless medicine, and one day, when I was assured by some familiar symptoms that my headache was about to assume an aggravated form, I took a larger quantity than had been prescribed. Twenty minutes later I was seized with a strange sinking or faintness which gave my family so much alarm that they telephoned at once for the doctor. "...One terrible reality--I can hardly term it a fancy even now--that came to me again and again, was so painful that it must, I fear, always be a vividly remembered agony....I died, as I believed, although by a strange double consciousness I knew that I should again reanimate the body I had left. In leaving it I did not soar away, as one delights to think of the freed spirits soaring....I sank, an intangible, impalpable shape, through the bed, the floors, the cellar, the earth, down, down, down! Like a fragment of glass dropping through the ocean, I dropped uninterruptedly through the earth and its atmosphere, and then fell on and on forever....As time went on, and my dropping through space continued, I became filled with the most profound loneliness, and a desperate fear took hold of me that I should be thus alone for evermore, and fall and fall eternally....There was, it seemed to me, a forgotten text which, if remembered, would be the spell to stop my fatal falling. I sought in my memory for it, I prayed to recall it, I fought for it madly, wrestling against the terrible fate which seemed to withhold it. Single words of it came to me in disconnected mockery, but erased themselves instantaneously. Mentally, I writhed in such hopeless agony that, in thinking of it, I wonder I could have borne such excess of emotion and lived....I began, then, without having reached any goal, to ascend. As I rose, a great and terrible voice from a vast distance pronounced my doom: 'Fall, fall, fall, to rise again in hopeless misery, and sink again in lonely agony forever.' ...Then ensued a wild and terrible commingling of unsyllabled sounds, so unearthly that it is not in the power of language to fitly describe them. It was something like a mighty Niagara of shrieks and groans, combined with the fearful din and crash of thousands of battles and the thunderous roar of a stormy sea....I fought my upward way in an agony which resembled nothing so much as the terrible moment when, from strangling or suffocation, all the forces of life struggle against death, and wrestle madly for another breath. In place of the woeful sounds now reigned a deadly stillness, broken only at long but regular intervals by a loud report, as if a cannon, louder than any I ever heard on earth, were discharged at my side, almost shot into me, I might say, for the sound appeared to rend me from head to foot, and then to die away into the dark chaos about me in strange, shuddering reverberations. Even in the misery of my ascending I was filled with a dread expectancy of the cruel sound. It gave me a feeling of acute physical torture, with a lingering intensity that bodily suffering could not have. It was repeated an incredible number of times, and always with the same suffering and shock to me. At last the sound came oftener, but with less force, and I seemed again nearing the shores of time. Dimly in the far distance I saw the room I had left, myself lying still and deathlike upon the bed, and the friends watching me....Then, silently and invisibly I floated into the room, and was one with myself again. "...'She is conscious now,' I heard one of the doctors say, and he gently lifted the lids of my eyes and looked into them. I tried my best to throw all the intelligence I could into them, and returned his look with one of recognition. But, even with my eyes fixed on his, I felt myself going again in spite of my craving to stay. I longed to implore the doctor to save me, to keep me from the unutterable anguish of falling into the vastness and vagueness of that shadowy sea of nothingness again. I clasped my hands in wild entreaty; I was shaken by horrible convulsions--so, at least, it seemed to me at the time--but, beyond a slight quivering of the fingers, no movement was discernible by the others....For five hours I remained in the same condition--short intervals of half-consciousness and then long lapses into the agonizing experiences I have described....Coming out of the last trance, I discovered that the measured rending report like the discharge of a cannon, which attended my upward way, was the throbbing of my own heart."] Concerning all these and other narcotics, it should never be forgotten that they are true poisons, sold with the mark of skull and crossbones, useful, like strychnine and henbane, in the hands of a skillful physician, but fraught with deadly danger when otherwise employed. Their private use is never safe. The weak and nervous invalid, who can not by hygienic means build up new strength, need never hope to gain it by surreptitiously indulging in popular narcotics. Instead, he will soon discover that he has but added to his list of ills a new and fatal one.--E. B. S. THE SPECIAL SENSES. AN EDUCATED SENSE OF TOUCH (p. 230).--Laura Dewey Bridgman, teacher in the Perkins Institute for the Blind, South Boston, lost her sight, hearing, and sense of smell, when she was two years of age. At the age of eight years she was taken to the institution where she yet remains. At this time, by following her mother around the house she had become familiar with home appointments, and by feeling her mother's hands and arms had also learned to sew and knit. When she first became an inmate of the Perkins Institute, she was bewildered by her strange surroundings, but after she had become used to place and people, through her one and only sense, her education was carefully begun. Through indomitable effort on the part of her preceptor, she was taught to write, read, and spell, by means of her fingers, and thus to exchange sentiments with her teachers and with others skilled in the mysterious language of the blind and the mute. She is now as proficient in the ordinary branches of learning as is the average person, possessed of all the senses. Her studies include geography, arithmetic, algebra, geometry, history, and philosophy. She makes her own clothing, can run a sewing machine, and observes great neatness in her dress and the arrangements of her room. Her character is religious, and she has great success as a teacher. Not long since, she celebrated, on the same day, her fifty-eighth birthday and the fiftieth anniversary of her entrance to the Perkins Institute. During her earlier years, it was her practice to keep a journal, and she now has about forty manuscript books of her own making. She has also written three autobiographical sketches, several poems, and is an accomplished correspondent. When Miss Bridgman expresses pleasure, she clasps her hands and smiles. So keen and refined are her sensibilities, that it is said she can, in a small way, appreciate the beauty of music by means of the sound vibrations on the floor.--MRS. GEORGE ARCHIBALD. (Laura D. Bridgman died in 1889.) THE NOSE (p. 232).--_The Anatomy of the Nose_.--Probably most of us look upon the nose as a double hole in the head, by which we get, with more or less acuteness, a sense of smell, and through which we occasionally breathe. The intricate mechanism, and the skillful adaptation of means to end, which, in common with the other organs of special sense, it exhibits, naturally do not reveal themselves to any but the students of anatomy and physiology. Its fourteen bones are probably better hidden than any other fourteen bones of the body, and assist in converting what would otherwise be a mere channel of communication, into a series of cavities designed and adapted for particular purposes. The arch of four bones which forms the bridge of the nose, and which is of such strength as to enable the gymnast of the circus to perform the feat of supporting with it a man on a ladder, is pieced on with cartilage to form the nostrils, through which the nose communicates with the outer air. Similar openings behind connect it with the upper and posterior parts of the mouth. The space between these anterior and posterior openings makes a large chamber, divided by a vertical wall into halves, each of which is still further separated into three irregular cavities by three bones, called spongy, from the porosity and delicacy of their texture. The ceiling of these chambers is formed by a bone of the thinness of paper, upon which lies the front part of the brain,--a fact the Egyptians made use of in embalming their corpses, easily crushing this bone, and extracting the brain through the nostrils. This bone is called cribriform (sieve-like), because it is perforated by many minute holes, through which, from the olfactory bulbs (specialized parts of the brain in which is resident the capacity of smell) that rest on its upper surface, issue the delicate filaments of the olfactory nerves, to spread themselves over the lining membrane of the two upper spongy bones. It is in the upper chambers of the nose, therefore, that the function of smell is performed; the nerves that supply the lower spongy bone being entirely unconnected with the organs of smell. Over these latter, however, sweep in and out the currents of air when the act of respiration is properly carried out, and it is these that are especially concerned in its abnormal performance. Usually but a very little of the volume of air that traverses the lower chamber of the nose has any influence upon its upper regions; and therefore, when our attention is attracted by an odor, we sniff, in order to bring a larger quantity of air into contact with the higher parts of the nose, or olfactory cavities, where odors are perceived. But the half has not been told of the anatomical and physiological arrangements of the nose. By minute openings its chambers have communication with many other parts of the head,--with the hollow that forms the greater part of the cheek bone; with the eye by a minute spout that carries off the lachrymal secretion, unless the tears are so abundant as to roll down the cheeks; with the front of the roof of the mouth; with the abundant cells of the bone that makes the forehead, and the congestion of whose lining membrane probably accounts for the severe headache that so often accompanies and aggravates a "cold in the head." The gateway to the inner air passages, its abundant surfaces raise the air inspired to the temperature of the body, supply it with the moisture it lacks, and sift from it more or less of the mechanical impurities with which the atmosphere of our houses and shops is laden.--MAURICE D. CLARKE, M.D., _Popular Science News, April, 1888_. _Smell Necessary to Taste_.--What we are in the habit of calling a "taste," is in most cases a compound of smell, taste, temperature, and touch--these four sensations ranking in gastronomic importance in the order in which they are here named....Amusing experiments may be made, showing that without the sense of smell it is commonly quite impossible to distinguish between different articles of food and drink. Blindfold a person and make him clasp his nose tightly, then put successively into his mouth small pieces of beef, mutton, veal, and pork, and it is safe to predict that he will not be able to tell one morsel from another. The same result will be obtained with chicken, turkey, and duck; with pieces of almond, walnut, and hazel-nut; with slices of apple, peach, and pear; or with different kinds of cheese, if care be taken that such kinds are chosen as do not, by their peculiar composition, betray their identity through the nerves of touch in the mouth. To hold an article of food under the nose at table would be justly considered a breach of etiquette. But there is a second way of smelling, of which most people are quite unconscious, viz., by _exhaling through the nose_ while eating and drinking....It is well known that only a small portion of the mucous membrane which lines the nostrils is the seat of the endings of the nerves of smell. In ordinary expiration, the air does not touch this olfactory region, but by a special effort it can be turned into that direction....Instinct teaches most persons while eating to guide the air, impregnated with the fragrance of the food, to a part of the nostrils different from that used during ordinary exhalation; but, being unaccustomed to psychologic analysis of their sensations, they remain quite unconscious of this proceeding, and are, indeed, in the habit of confusing their sensations of taste, smell, touch, and temperature in a most absurd manner.... In trying to ascertain by experiment how far smell, touch, and temperature enter into this compound sensation, popularly known as "taste," it is best to make use of the pungent condiments. Mustard and horse-radish, for example, have little or no taste, but reserve their pungent effect for the mucous membrane of the nose during expiration. It is an advantage to know this, for if care is taken to breathe only through the mouth, we need no longer prepare to shed tears every time we help ourselves to the mustard. The pungent quality of mustard, the fiery quality of ginger, and the cool sensation in the mouth after eating peppermint, are due to the nerves of touch and temperature, which are commonly classed as one sense, though they are quite as distinct sensations as sight and hearing, or taste and smell.... There are two ways in which the effort to extract all its fragrance from a morsel of food confers a benefit. (1.) It is necessary to keep the morsel in the mouth as long as possible. Now the habit thus formed of eating very slowly is of the utmost importance, for if farinaceous articles of food are swallowed before the saliva has had time to act on them, they are little better than so much waste material taken into the system; and if meat is not thoroughly masticated, the stomach is overloaded with work which should have been done by the teeth; the result, in either case, is dyspepsia. It has been suggested that Mr. Gladstone owes his remarkable physical vigor to certain rules for chewing food, which he adopted in 1848, and to which he has adhered ever since. "He had always," we are told, "paid great attention to the requirements of Nature, but he then laid down as a rule for his children that thirty-two bites should be given to each mouthful of meat, and a somewhat lesser number to bread, fish, etc." (2.) Besides this indirect advantage resulting from the effort to get at the fragrant odors of food, there is a still more remarkable direct advantage. It is one of the most curious psychologic facts that odors exert a strong influence on our system, either exhilarating or depressing. While an unpleasant odor may cause a person to faint, the fumes of the smelling bottle will restore him to consciousness. The magic and value of gastronomic odors lies in this, that they stimulate the flow of saliva and other alimentary juices, thus making sure that the food eaten will be thoroughly utilized in renovating the system.--HENRY T. FINCK, _in "The Gastronomic Value of Odors_." HYGIENE OF THE EAR (p. 236).--_Never Box a Child's Ear_.--Children and grown persons alike may be entirely deafened by falls or heavy blows upon the head. Boxing the ears produces a similar effect, though more slowly and in less degree, and tends to dull the sensibility of the nerve, even if it does not hurt the membrane. I knew a youth who died from a terrible disease of the ear. There had been a discharge from it since he was a child. Of course his hearing had been dull; and _his father had often boxed his ear for inattention!_ Most likely that boxing on the ear, diseased as it was, had much to do with his death. And this brings me to the second point. Children should never be blamed for being inattentive, until it has been found out whether they are not a little deaf. This is easily done by placing them at a few yards' distance, and trying whether they can understand what is said to them in a rather low tone of voice. Each ear should be tried, while the other is stopped by the finger. Three things should be remembered here: 1. That slight degrees of deafness, often lasting only for a time, are very common among children, especially during or after colds. 2. That a slight deafness, which does not prevent a person from hearing when he is expecting to be spoken to, will make him very dull to what he is not expecting. 3. That there is a kind of deafness in which a person can hear pretty well while listening, but is really very hard of hearing when not listening. _Avoid Direct Draughts in the Ear_.--There are some exposures especially to be guarded against. One is sitting or driving with the ear exposed to a side wind. Deafness has also been known to come from letting rain or sleet drive into the ear. _Do not Remove the Earwax_.--It ought to be understood that the passage of the ear does not require cleaning by us. Nature undertakes that task, and, in the healthy state, fulfills it perfectly. Her means for cleansing the ear is _the wax_. Perhaps the reader has never wondered what becomes of the earwax. I will tell him. It dries up into thin fine scales, and these peel off, one by one, from the surface of the passage, and fall out imperceptibly, leaving behind them a perfectly clean, smooth surface. In health the passage of the ear is never dirty; but, if we attempt to clean it, we infallibly make it so. Washing the ear out frequently with soap and water keeps the wax moist when it ought to become dry and scaly, increases its quantity unduly, and makes it absorb the dust with which the air always abounds. But the most hurtful thing is introducing the corner of the towel, screwed up, and twisting it round. This does more harm to ears than all other mistakes together. It drives down the wax upon the membrane, much more than it gets it out. But this plan does much more mischief than merely pressing down the wax. It irritates the passage, and makes it cast off small flakes of skin, which dry up, and become extremely hard, and these also are pressed down upon the membrane. Often it is not only deafness which ensues, but pain and inflammation, and then matter is formed which the hard mass prevents from escaping, and the membrane becomes permanently diseased. _The Eustachian Tube_.--The use of this tube is twofold. First, it supplies the drum with air, and keeps the membrane exactly balanced, and free to move, with equal air pressure on each side; and, secondly, it carries off any fluid which may be in the drum, and prevents it from being choked by its own moisture. It is not always open, however, but is opened during the act of swallowing, by a little muscle which is attached to it just as it reaches the throat. Most persons can distinctly feel that this is the case, by gently closing the nose and swallowing, when a distinct sensation is felt in the ears. This sensation is due to a little air being drawn out of the ears through the open tube during swallowing; and it lasts for a few minutes, unless the air is again restored by swallowing with the nose unclosed, which allows for the moment a free communication between the ear and the throat. We thus see a reason for the tube being closed. If it were always open, all the sounds produced in the throat would pass directly into the drum of the ear, and totally confuse us. We should hear every breath, and live in a constant bewilderment of internal sounds. At the same time the closure, being but a light contact of the walls of the tube, easily allows a slight escape of air _from_ the drum, and thus not only facilitates and regulates the oscillations of the air before the vibrating membrane, but provides a safety valve, to a certain extent, against the injurious influence of loud sounds. The chief use of the Eustachian tube is to allow a free interchange of air between the ear and the throat, and it is very important that its use in this respect should be understood. Persons who go down in diving bells soon begin to feel a great pressure in the ears, and, if the depth is great, the feeling becomes extremely painful. This arises from the fact that in the diving bell the pressure of the air is very much increased, in order to balance the weight of the water above; and thus it presses with great force upon the membrane of the drum, which, if the Eustachian tube has been kept closed, has only the ordinary uncompressed air on the inner side to sustain it. It is therefore forced inward and put upon the stretch, and might be even broken. Many cases, indeed, have occurred of injury to the ear, producing permanent deafness, from descents in diving bells, undertaken by persons ignorant of the way in which the ear is made; though the simple precaution of frequent swallowing suffices to ward off all mischief. For, if the Eustachian tube is thus opened, again and again, as the pressure of the outside air increases, the same compressed air that exists outside passes also into the inside of the drum, and the membrane is equally pressed upon from both sides by the air, and so is free from strain. The same precaution is necessary in ascending lofty mountains.-- DR. JAMES HINTON. THE COLORED CURTAIN IN THE EYE (p. 238).--This ring-like curtain in the eye, of gray, green, bluish-green, brown, and other colors, is one among the very many remarkable contrivances of the organic world. The eye can not bear the entrance of too much light, and the colored curtain so regulates its own movements as to serve this requirement. The dark circular aperture in the center, known as the pupil, is consequently forever altering in size; on a bright, sunshiny day, out in the open, it may be only the size of a pin's head, but at night, when there is no light stronger than starlight, it is even bigger than a pea. The eye curtain is fixed at its outer edge, leaving the inner edge to contract or expand, which it does automatically and quite independent of the will, ever preserving its circular outline. Its movements may be watched in a variety of ways, some of which we shall describe. The common way of watching the movements of the iris is to regard it closely in a looking-glass while the amount of light entering the eyes is varied. Place yourself before a looking-glass and with your face to the window. Probably the iris will be expanded, and there will only be a very small opening or pupil in the center. Now shut one eye suddenly, while narrowly watching the other in the glass all the time. At the moment the light is cut off from one eye, the iris of the other contracts or is drawn up so as to enlarge the pupil. This shows that there is a remarkable interdependence between the curtains of the two eyes, as well as that they are affected by variations in the quantity of light falling on them. Perhaps one of the most interesting ways of watching the movements of these sympathetic eye curtains is one which may be followed while you are out walking on the street some dark winter night. A gas lamp seen at a distance is, comparatively speaking, a point of light, with bars of light emanating from it in many directions. These bars, which give the peculiar spoked appearance to a star, are probably formed by optical defects of the lens within the eye, or by the tear fluid on the exterior surface of the eye, or by a combination of all these causes. Be that as it may, the lengths of the spokes of light are limited by the inner margin of the eye curtain; if the curtain be drawn up, then the spokes are long; if the curtain be let down, or, in other words, if the pupil be very small and contracted, then one can not see any spokes at all. Hence, as I look at a distant gaslight, with its radiating golden spokes, I am looking at something which will give me a sure indication of any movements of the eye curtains. I strike a match and allow its light to fall into the eyes; the spokes of the distant gas lamp have retreated into the point of flame as if by magic; as I take the burning match away from before my eyes, the spokes of the gas-lamp venture forth again. The experiment may be utilized to see how much light is required to move the window curtains of the eyes. Suppose you are walking toward two gas lamps, A and B; B about fifty yards behind A. If you steadfastly look at B and at the golden spokes apparently issuing from it, you may make these spokes a test of how soon the light of A will move your iris. As you gradually approach A, you come at last to a position where its light is strong enough to make the spokes of B begin to shorten; a little nearer still and they vanish altogether. I have found that about a third of the light which is competent to contract the pupil very markedly will serve to commence its movement.--WILLIAM ACKROYD. PURKINJE'S FIGURES (p. 222).--Stand in a dark room with a lighted candle in hand. Shutting the left, hold the candle very near the right eye, within three or four inches, obliquely outward and forward, so that the light shall strongly illuminate the retina. Now move the light about gently, upward, downward, back and forth, while you gaze intently on the wall opposite. Presently the field of view becomes dark from the intense impression of the light, and then, as you move the light about, there appears projected on the wall and covering its whole surface, a shadowy, ghost-like image, like a branching, leafless tree, or like a great bodiless spider with many branching legs. What is it? It is an exact but enlarged image of the _blood vessels of the retina_. These come in at the entrance of the optic nerve, ramify in the middle layer, and therefore in the strong light cast their shadows on the bacillary layer of the retina. The impression of these shadows is projected outward into the field of view, and seen there as an enlarged shadowy image. These have been called Purkinje's Figures, from the discoverer.--PROF. JOSEPH LE CONTE, _in Sight_. XI. APPENDIX. QUESTIONS FOR CLASS USE. _The questions include the Notes and the Selected Readings. The figures refer to the pages_. INTRODUCTION. Illustrate the value of physiological knowledge. Why should physiology be studied in youth? When are our habits formed? How do habits help us? Why should children prize the lessons of experience? How does Nature punish a violation of her laws? Name some of Nature's laws. What is the penalty of their violation? Name some bad habits and their punishments. Some good habits and their rewards. How do the young ruin their health? Compare one's constitution with a deposit in the bank. Can one in youth lay up health as he can money for middle or old age? Is not the preservation of one's health a moral duty? What is suicide? THE SKELETON. 3. How many bones are there in the body? Is the number fixed? Is the length of the different bones proportional? What is an organ? A function? Name the three uses of the bones. Why do the bones have such different shapes? 4. Why are certain bones hollow? Round? Illustrate. Compare the resisting property of bone with that of solid oak. What is the composition of bone? How does it vary? How can you remove the mineral matter? The animal matter? Why is a burned bone white and porous? What food do dogs find in bones? 5. What is the use of each of the constituents of a bone? What is "boneblack"? What is ossification? Why are not the bones of children as easily broken as those of aged persons? Why do they unite so much quicker? What are the fontanelles? 6. Describe the structure of a bone. What is the object of the filling? Why does the amount vary in different parts of a bone? What is the appearance of a bone seen through a microscope? 7. What is the periosteum? Is a bone once removed ever restored? What are the lacunæ? The Haversian canals? Why so called? _Ans_. From their discoverer, Havers. Define a bone. [Footnote: Bone structure may be summarized as follows: A bone is a collection of _Haversian elements_, or rods. An Haversian element consists of a tube surrounded by _lamellæ_, which contain _lacunæ_, connected by _canaliculi_.--DR. T. B. STOWELL.] What occupies the lacunæ? _Ans_. The bone cells (osteoblasts). How do bones grow? 8. Illustrate. How does a broken bone heal? How rapidly is bone produced? Illustrate. Objects of "splints"? Describe how a joint is packed. Lubricated. 9. How are the bones tied together? What is a tissue? Illustrate. Name the three general divisions of the bones. What is the object of the skull? Which bone is movable? How is the lower jaw hinged? Describe the construction of the skull. What is a suture? 10. Tell how the peculiar form and structure of the skull adapt it for its use. Illustrate the impenetrability of the skull. 11. Describe the experiment of the balls. What does it show? What two cavities are in the trunk? Name its principal bones. Describe the spine. 12. What is the object of the processes? Of the pads? Why is a man shorter at night than in the morning? Describe the perfection of the spine. 13. Describe the articulation of the skull with the spine. Why is the atlas so called? 14. Describe the ribs. What is the natural form of the chest? Why is it made in separate pieces? How does the oblique position of the ribs aid in respiration? (See note, p. 80.) 15. How do the hipbones give solidity? What two sets of limbs branch from the trunk? State their mutual resemblance. Name the bones of the shoulder. Describe the collar bone. 16. Describe the shoulder blade. Can you describe the indirect articulation of the shoulder blade with the trunk? Name the bones of the arm. Describe the shoulder joint. The elbow-joint. 17. Describe the wrist. Name the bones of the hand. How many bones in the fingers? The thumb? What gives the thumb its freedom of motion? 18, 19. Name and describe the fingers. In what lies the perfection of the hand? How do the gestures of the hand enforce our ideas and feelings? Describe the hip joint. What gives the upper limbs more freedom of motion than the lower? How does the pressure of the air aid us in walking? Illustrate. 20. Name the bones of the lower limbs. Describe the knee joint. The patella. What is the use of the fibula? Can you show how the lower extremity of the fibula, below its juncture with the tibia, is prolonged to form a part of the ankle joint? Name the bones of the foot. What is the use of the arch of the foot? What makes the step elastic? Describe the action of the foot as we step. 21. In graceful walking, should the toes or the heel touch the ground first? What are the causes of deformed feet? What is the natural position of the big toe? Did you ever see a big toe lying in a straight line with the foot, as shown in statuary and paintings? How should we have our boots and shoes made? What are the effects of high heels? Of narrow heels? Of narrow toes? Of tight-laced boots? Of thin soles? What are the rickets? Cause of this disease? Cure? Is there any provision for remedying defects in the body? Name one. 22, 23. What is a felon? Cure? Cause of bowlegs? How can they be prevented? Causes of spinal curvature? Cure? What is the correct position in sitting at one's desk? Is there any necessity for walking and sitting erect? Any advantage aside from health? Describe the bad effects of a stooping position. What is a sprain? Why does it need special care? What is a dislocation? How is it generally caused? How soon should it be treated? 269. What relation does man, in his general structure, bear to other vertebrates? Mention some marked physical peculiarities which distinguish him from the lower mammals. 270, 271. Describe the state of a fracture a week after its occurrence. What is this new formation called? What marks the termination of the first stage of curative progress? How do the broken ends of the bone now appear? What is the state of the fracture at the end of the second stage? What is the condition of the callus at this time? Describe the third and last series of changes. Is the process of union completed sooner in old people or in young? In the upper or lower extremities? In smaller animals or man? What length of time is required to heal a broken arm? A broken leg? 272. What gives the human hand its peculiar prehensile power? What advantage has the human thumb over that of the ape? Compare the foot of man with that of the ape. What peculiarity of the foot is particularly noticeable in man? Contrast the function of the great toe in man and in the ape. 273. Are the toes naturally flexible? How are their powers crippled? Give an instance in which the toes were trained to do the work of the fingers. 274. Why are an elastic step and a graceful carriage such rare accomplishments? What is the natural shape of the foot? Which is the longer, the great toe or the second toe? Is an even-sided symmetry necessary to the beauty of a boot? THE MUSCLES. 29. What relations do the skeleton and the muscles bear to each other? How is the skeleton concealed? Why is it the image of death? What are the muscles? How many are there? What peculiar property have they? Name other properties of muscles. _Ans_. Tonicity, elasticity. 30. How are they arranged? Where is the biceps? The triceps? How do the muscles move the limbs? Illustrate. What is the cause of squinting? Cure? (See p. 244.) 31. Name and define the two kinds of muscles. Illustrate each. What is the structure of a muscle? Of what is a fibril itself composed? How does the peculiar construction of the muscle confer strength? 32. Describe the tendons. What is their use? Illustrate the advantages of this mode of attachment. 33. What two special arrangements of the tendons in the hand? Their use? How is the rotary motion of the eye obtained? 34, 35. What is a lever? Describe the three classes of levers. Illustrate each. Describe the head as a lever. What parts of the body illustrate the three kinds of levers? Give an illustration of the second class of levers. The third class. Why is the Tendon of Achilles so named? What is the advantage of the third class of levers? Why desirable in the hand? What class of lever is the lower jaw? 36. What advantages are gained by the enlargement of the bones at the joints? Illustrate. How do we stand erect? Is it an involuntary act? 37. Why can not a child walk at once, as many young animals do? Why can we not hold up the head easily when we walk on "all fours"? Why can not an animal stand erect as man does? 38. Describe the process of walking. Show that walking is a process of falling. Describe the process of running. What causes the swinging of the hand in walking? Why are we shorter when walking? [Footnote: Stand a boy erect against a wall. Mark his height with a stick. Now have him step off a part of a pace, and then several whole paces. Next, let him close his eyes, and walk to the wall again. He will be perceptibly lower than the stick, until he straightens up once more from a walking position.] Why does a person when lost often go in a circle? In which direction does one always turn in that case? [Footnote: Take several boys into a smooth grass lot. Set up a stick at a distance for them to walk toward. Test the boys, to find which are left-handed, or right-handed; which left-legged or right-legged. Then blindfold the boys and let them walk, as they think, toward the mark. See who varies toward the right, and who turns to the left.] 39. What is the muscular sense? Value of educating it? How do we gratify it? 40. What effect has exercise upon a muscle? Is there any danger in violent exercise? For what purpose should we exercise? Should exercise be in the open air? What is the rule for exercise? Is a young person excusable, who leads a sedentary life, and yet takes no daily outdoor exercise? What will be Nature's penalty for such a violation of her law? Will a postponement of the penalty show that we have escaped it? 41. Ought a scholar to study during the time of recess? Will a promenade in the vitiated air of the schoolroom furnish suitable exercise? What is the best time for taking exercise? What class of persons can safely exercise before breakfast? 42. What are the advantages of the different kinds of exercise? Should we not walk more? What is the general influence upon the body of vigorous exercise? 43. State some of the wonders of the muscles. What is the St. Vitus's Dance? Cure? 44. What are convulsions? What is the locked-jaw? Causes? The gout? Cause? Cure? The rheumatism? Its two forms? Peculiarity of the acute? 45. Danger in acute rheumatism? In what does chronic rheumatism often result? What is lumbago? Give instances. What is a ganglion? Its cure? A bursa? 275. What is meant by the origin of a muscle? The attachment? Is a muscle always extended between two contiguous bones? Give an illustration. Can the points of origin and of attachment change offices? Illustrate. What is an important consequence of the attachment of the muscles to the bones? If, in the limb of a dead body, one end of a muscle is separated from its point of attachment, what occurs? Would the result be the same during life? To what is this phenomenon due? 276. Why are the muscles continually striving to shorten? Describe the effect when several opposing muscles are attached to one bone. When is the balanced position of the limbs best observed? Are the muscles always attached to bones? Give example. How does the flesh of man differ from that of an ox? How may the structure of muscular fibers be rudely illustrated? Describe smooth muscle fibers. How do they differ from striated muscle fibers? 277. In what form do smooth muscle fibers frequently occur? In such cases, how are they usually arranged? What is the effect of their contraction? Of what especial use is this power in case of the smaller arteries? In case of the intestine? 278. In the latter instance, how does the contraction take place? Are the striated muscle fibers voluntary or involuntary? Name an exception to this rule. Give other peculiarities of the muscle fibers of the heart. What causes the contraction of smooth muscle fibers? Of striated muscle fibers? Why do little children seldom injure themselves by overexertion? How is the danger increased in youth? 279. What class of people are in most peril from violent or excessive exercise? Why? At what age should one cease from haste of all kinds? Give instances of valuable lives lost from personal imprudence. 280. What are the effects of insufficient exercise upon the young? How does it predispose to disease? What makes the children of the laboring classes so hardy? Is a regulation step desirable in walking? Why not? Why is it more fatiguing to walk uphill than on level ground? 281. How does the management of the breath affect this fatigue? How should a belt be worn, if used during exercise? Can other forms of exercise be successfully substituted for walking? Why not? What is the difference in movement between walking and skating? Which is the better exercise? What are the dangers from skating? What precaution should be used by those who have weak ankles? 282. Name the different action of the muscles in the forward and backward movements in rowing. What is the comparative value of rowing as an exercise? Why is it especially desirable for women? How should women dress when rowing, horseback riding, tennis playing, etc.? What rules should be observed by rowers? Why should the breath be allowed to escape while the oar is in the water? 283. What sanitary measures should be observed after a row? What effect has too frequent and too prolonged immersion on young swimmers? Does swimming require much muscular exertion? Why? Why does an occasional swimmer become exhausted sooner than an experienced one? On what do ease and speed in swimming depend? Is the habit of diving desirable? Should diving ever be practiced in shallow water? 284. Why is lawn tennis the most desirable of outdoor games? _Ans_. Not only because nearly every muscle of the body is brought into exercise, but because it is one of the few field sports in which women can gracefully join. In this it shares the honor with croquet. What are the dangers attendant on lawn tennis? From what do many of them arise? Why should tennis shoes have heels? To what class of people is horseback riding particularly suited? What class of invalids should not indulge in bicycling and tricycling? To what class is it peculiarly beneficial? 285. What are the dangers attendant on baseball games? Football? When may light and heavy gymnastics be profitably employed? Name a sufficient apparatus. What are the objections to gymnasium exercise? Its advantages? THE SKIN. 49. What are the uses of the skin? Describe its adaptation to its place. What is its function as an organ? Describe the structure of the skin. The sensitiveness of the cutis. The insensitiveness of the cuticle. 50. How is the skin constantly changing? The shape and number of the cells? Value of the cuticle? How is the cuticle formed? _Ans_. By secretion from the cutis. 51. What is the complexion? Its cause? Why is a scar white? What is the cause of "tanning"? What are freckles? Albinos? Describe the action of the sun on the skin. 52. Why are the hairs and the nails spoken of under the title of the skin? Uses of the hair? Its structure? How can it be examined? What is the hair bulb? What is it called? How does a hair grow? At what rate? When can it be restored, if destroyed? Does hair grow after death? 53. When hair has become gray, can its original color be naturally restored? What is the danger of hair dyes? Are they of any real value? How can the hair stand on end? How do horses move their skin? Is there any feeling in a hair? 54. Illustrate the indestructibility of the hair. What are the uses of the nails? How do the nails grow? What is the mucous membrane? 55. Its composition? The connective tissue? Why so called? What uses does it subserve? 56. What is its character? How does the fat exist in the body? Its uses? State the various uses of membrane in the body. Where is there no fat? Where is there always fat? 57. Why are the teeth spoken of in connection with the mucous membrane? Name and describe the four kinds of teeth. What are the milk teeth? Describe them. What teeth appear first? 58. Give the order and age at which they appear. When do the permanent teeth appear? Describe their growth. Which one comes first? Last? 59. Describe the structure of the teeth. How are the teeth fitted in the jaw? 60. Why do the teeth decay? What care should be taken of the teeth? What caution should be observed? What are the oil glands? 61. Use of this secretion? What are the perspiratory glands? State their number. Their total length. What are the "pores" of the skin? 62, 63. What is the perspiration? What is the constitution of the perspiration? Illustrate its value. Name the three uses of the skin. Illustrate the absorbing power of the skin. What precaution should be observed in handling a dead body? Why are cosmetics and hair dyes injurious? What relation exists between the skin and the lungs? What lesson does this teach? When is the best time for a bath? Why? 64, 65. What is the value of friction? Why should not a bath be taken just before or after a meal? Is an excess of soap beneficial? What is the "reaction"? Explain its invigorating influence. How is it secured? General effect of a cold bath? Of a warm bath? If we feel chilly and depressed after a bath, what is the teaching? Describe the Russian vapor bath. Why is the sea bath so stimulating? 66. How long should one remain in any bath? How does clothing keep us warm? Explain the use of linen as an article of clothing. Cotton. Wool. Flannel. How can we best protect ourselves against the changes of our climate? 67. What colored clothing is best adapted for all seasons? Value of the nap? Furs? Thick _vs_. thin clothing? Should we wear thick clothing during the day, and in the evening put on thin clothing? Can children endure exposure better than grown persons? What is the erysipelas? How relieved? 68, 69. Eczema? What do its various forms denote? Corns? Cause? Cure? Ingrowing nails? Cure? Warts? Cure? Chilblain? Cause? Preventive? 286. Name some causes of baldness. Give Dr. Nichols's opinion. Why is frequent shampooing inadvisable? One probable reason why women are less frequently bald than men? What is the best general treatment for the hair and scalp? Upon what does the color of the hair mainly depend? 287. In cases of sudden blanching of the hair what is the effect upon the pigment? Give an illustration. How do the extra air bubbles find their way into the hair? Does air naturally exist in the hair? What relation do the nails bear to the scarfskin? 288. What causes the horny appearance of the nails? Describe the root of the nail in its relation to the sensitive and the scarfskin. Upon what does the nail rest? What is its appearance? What is the lunula? Why is it lighter than the rest of the nail? How does the nail increase in length? In thickness? Where is the greatest thickness? How does the growth of the nail during disease compare with its growth in health? 289. How long does it take the thumb nail to grow from its root to its free extremity? The great toe? Give general rules for the care of the nails. How does physical cleanliness promote moral purity? What does its neglect indicate? 290. What especial care should be taken in regard to the feet? Why? Are baths a modern refinement? What can you say about the ancient Greek and Roman baths? What constitutes the value of the Turkish bath? 291. What class of people should never use this bath? To what class of invalids is it particularly beneficial? Is sea bathing advisable for persons of all ages? How should an inexperienced sea bather begin? When should the sea bath be taken? 292. How long should a delicate person remain in the water? State the danger of bathing when overheated. Under what conditions of body and of temperature should sea or river bathing be avoided? Why? Give illustration of the English soldier. How should the temperature of the water, in bathing, compare with that of the air? Of the body? 293. Describe the bathers' cramp. What are its causes? What precaution should be used by bathers in regard to the mouth and ears? Why? 294. How can a person who does not know how to swim, save himself from drowning? 295. What are the advantages of woolen clothing? Why is it particularly desirable in malarial countries? What double purpose does woolen clothing serve in semitropical climates? 296. Does the warmth of clothing depend on its weight? What errors are often made and with what effect? State what is said in regard to poisonous dyes in wearing apparel. Give illustration. 297. What effect has uncleanly attire on the health? Does this apply to outer as well as under garments? RESPIRATION AND THE VOICE. 73. Name the organs of respiration and the voice. Describe the larynx. The epiglottis. The œsophagus. What is meant by food "going the wrong way"? 74. Describe the vocal cords. Their use. How is sound produced? 75. How are the higher tones of the voice produced? The lower? Upon what does loudness depend? A falsetto voice? What is the cause of the voice "changing"? What is speech? Is the tongue necessary to speech? Illustrate. (See also page 298.) 76. What is vocalization? How are talking machines made? 77. How is _a_ formed by the voice? What is _h_? Difference between a sigh and a groan? What vowel sounds are made in laughing? Does whistling depend on the voice? Tell how the various consonants are formed. What are the labials? The dentals? The linguals? What vowels does a child pronounce first? 78. Describe the windpipe. The bronchi. The bronchial tubes. Why is the trachea so called? Describe the structure of the lungs. What are the lungs of slaughtered animals called? Why will a piece of the lungs float on water? 79. Name the wrappings of the lungs. Describe the pleura. How is friction prevented? What are the cilia? Their use? 80. What two acts constitute respiration? In what two ways may the position of the ribs change the capacity of the chest? Describe the process of inspiration. Describe the diaphragm. 81. What is the process of expiration? How often do we breathe? What is sighing? Coughing? Sneezing? Snoring? Laughing? Crying? 82. Describe hiccough. Yawning. Its value? What is meant by the breathing capacity? How does it vary? How much, in addition, can the lungs expel forcibly? How much of the breathing capacity is available only through practice? Value of this extra supply? Can we expel all the air from our lungs? Value of this constant supply? 83. How constant is the need of air? What is the vital element of the air? Describe the action of the oxygen in our lungs. What does the blood give up? Gain? What are the constituents of the air? What are the peculiar properties and uses of each? 84. How can we test the air we exhale? What does its analysis reveal? Which is the most dangerous constituent? What occurs when we rebreathe exhaled air? 85. Describe its evil effects. What is denoted by the "Black Hole of Calcutta"? Give other illustrations of the dangers of bad air. Describe the need of ventilation. Will a single breath pollute the air? 86-95. How can we detect the floating impurities in the air? What is the influence of a fire or a light? Of a hot stove? When is the ventilation perfect? What diseases are largely owing to bad air? Should the windows and doors be tightly closed, if we have no other means of ventilation? Is not a draught of air dangerous? How can we prevent this, and yet secure fresh air? What is the general principle of ventilation? Must pure air necessarily be cold air? Are schoolrooms always properly ventilated? What is the effect? Are churches? Are our bedrooms? Should children or delicate people sleep in cold rooms? Can we, at night, breathe anything but night air? Is the night air out of doors ever injurious? _Ans_. In times and places of malaria, and also in very damp weather, it should be avoided, even at the risk of bad air in doors. Describe some of the wonders of respiration. 96. How is constriction of the lungs produced? When may clothing be considered tight? What are the dangers of tight lacing? Which would make the stronger, more vigorous, and longer-lived person, the form shown in _A_ or _B_, Fig. 33? Is it safe to run any risk in this dangerous direction? 97. What is Bronchitis? Pleurisy? Pneumonia? Consumption? What is one great cause of Consumption? How may a constitutional tendency to this disease be warded off in youth? _Ans_. Besides plenty of fresh air and exercise, care should be taken in the diet. Rich pastry, unripe fruit, salted meat, and acid drinks should be avoided, and a certain quantity of fat should be eaten at each meal.--BENNETT. What is asphyxia? Describe the process for restoring such a person. (See p. 264.) 98. What is diphtheria? Its peculiarities? Danger? The croup? Its characteristics? Remedy? (See p. 260.) Causes of stammering? How cured? 297. How does the singing voice differ from the speaking voice? How can you prove the effect of duration of sound in speaking and singing? How do the intonations of the voice affect the meaning of words? 298. Give illustrations of speech in persons without a tongue. What is the effect of alcohol and tobacco on the throat? Do they have an influence on the voice? Does the excessive use of tea and coffee ever affect the voice? How? To what is the hoarse tone of an inebriate due? 299, 300. What was Adelina Patti's advice with regard to stimulants and late hours? Does the respiration of woman differ from that of man? Give experiments with Indian women. What lessons do we draw from these facts? What rule should be observed in regard to the size of a bodice? What are bacteria or microbes? How is their existence revealed? What does the Germ Theory of Disease teach in regard to microbes? 301. What can you say about the microbe of putrefaction? How can you obtain it for examination? What office in Nature do bacteria seem to serve? Give the theory in regard to propagation of special disease germs. Do they always cause disease when taken into the body? [Footnote: Of the immense number and variety of microorganisms found in Nature, only very few are disease producing. Dr. Austin Flint says in _The Forum_, for December, 1888: "It is probable that future investigations into the physiology of digestion, will show that bacteria play an important part in this function. Pasteur has recently isolated no less than seventeen different microorganisms in the mouth, which were not destroyed by the gastric juice. Some of these dissolved albumen, gluten, and caseine, and some transformed starch into sugar. Bacteria normally exist in great number and variety in the intestines, although the part which they take in intestinal digestion has not been accurately determined."--The number of spores introduced into the human system by respiration, when the health is perfectly sound, has been estimated at three hundred thousand a day.] 302. State some conditions which favor the growth of disease germs. Which prevent or retard their growth. Relate the effect of vaccination, according to the germ theory. 303. 304. If a drop of an infusion charged with bacteria be put in the extract of beef or mutton, what is the result? What would be the effect upon an open wound? Give Dr. Tyndall's personal experience. Name some efficient antidote against the bacteria of putrefaction. _Ans_. Carbolic acid solution is extensively used for this purpose. How are disease germs often disseminated? State the necessity of disinfection in regard to soiled clothing. 305. Illustrate how disease has been communicated by clothing. What is the first necessary condition to a sanitary home? What is the meaning of the word malaria? What are three active agents in the production of malaria? A fourth? Describe a typical malarious locality. How does newly broken ground induce malaria? 306. State the different ways in which running water can be contaminated. What care should be taken in regard to the level of building site? 307. Give some of the results of a wet foundation. What rules should be observed in regard to shade? What is the effect of too dense foliage about a dwelling? In building a house, what precautions should be taken against dampness? What about the cellar? Sewerage? Plumbing? Ventilation? Fireplaces? Piazzas and balconies? Sleeping rooms? 308. What general purpose does a house serve? What care should be taken in regard to the dust or ash heap? What is the effect if liquids or table refuse be thrown upon it? Where should it be situated? How often should refuse be carted away? If its frequent removal be inexpedient, what precaution should be used? What are the best of all deodorizers? How should the back premises be cared for? What is the best way to dispose of household garbage? 309. How can this be done? With what additional advantage? Give Dr. Derby's remarks in regard to sewers, their condition, and the results. How should traps and drains be cared for? How should bad smells be treated? Is a foul smell always the most dangerous? How do poisonous gases often find entrance to a house? What rule should be observed in regard to ventilating and soil pipes? 310. What precautions should be observed in digging about a dwelling? How do waste pipes often become closed? How may they be cleared? What dangers arise from unventilated waste pipes? How are washbasin pipes contaminated? Tell what came from a neighbor's cesspool. Can you name similar instances which have come under your own observation? 311, 312. Describe the condition and effects of a neglected cellar. Tell what came from a crack in a cellar wall. 313. What effect have brick and mortar in keeping out gases? How do bed coverings take the place of day garments? What kind of bed covering is desirable? Is a comfortable bed necessary to perfect health? How often and for how long time should a bed be ventilated? THE CIRCULATION. 105. Name the organs of the circulation. Does the blood permeate all parts of the body? What is the average amount in each person? Its composition? The plasma? The red corpuscles? The white? 106. What is the size of a red cell? Are the shape and size uniform? Value of this? Illustrate. Are the disks permanent? What substances are contained in the plasma? What is fibrin? 107. In what sense is the blood "liquid flesh"? What is the use of the red disks? What is the office of the oxygen in the body? Where is the blood purified? 108. What is transfusion? Is it of value? 109. Give some illustrations. What is the cause of coagulation of the blood? Value of this property? Has the fibrin any other use? 110. What organ propels the blood? What is the location of the heart? How large is it? Put your hand over it. What is the pericardium? Describe the systole. 111. The diastole. How many chambers in the heart? What is their average size? What is meant by the right and left heart? What are the auricles? Why so called? The ventricles? 112. What is the use of the auricles? The ventricles? Which are made the stronger? Show the need of valves in the ventricles. Why are there no valves in the auricles? Draw on the board the form of the valves. Name them. 113. Describe the tricuspid valve. The bicuspid. How are these valves strengthened? 114. What peculiarity in the attachment of these cords? Describe the semilunar valves. What are the arteries? Why so named? What is their use? Their structure? How does their elasticity act? What is meant by a "collateral circulation"? 115. How are the arteries protected? Where are they located? Give a general description of the arterial system. What is the aorta? What is the pulse? On which arteries can we best feel it? What is the average number of beats per minute? How and why does this vary? 116. Why does a physician feel a patient's pulse? What are the veins? What blood do they carry? Describe the venous system. What vein does not lead toward the heart? Describe the valves of the veins. What valves of the heart do they resemble? What are varicose veins? 117. Where and how can we see the operation of these valves? What are the capillaries? What is the function of the capillaries? [Footnote: The distinctive function of the capillaries is to offer peripheral resistance to the circulation of the blood. This insures "blood pressure," a condition indispensable to the "heart beat," and also causes leakage (transudation). This leakage brings the nutriment in contact with the tissue cells, whereby they are renewed. In the same way the air passes from the blood to the cells.] What changes take place in this system? 118. Describe the circulation of the blood as seen in the web of a frog's foot. 119. Who discovered the circulation of the blood? How was the discovery received? What remark did Harvey make? What does that show? Name the two divisions of the circulation. Describe the route of the blood by the diagram. 1. The lesser circulation. 2. The greater circulation. 120. What is the velocity of the blood? How long does it require for all the blood to pass through the heart? How long does it take the blood to make the tour of the body? What is the average temperature of the body? How much does this vary in health? _Ans_. Not more than 2°, even in the greatest extremes of temperature.--FLINT. 121. How and where is the heat of the body generated? How is it distributed? In what diseases is the variation of temperature marked? How is the temperature of the body regulated? 122. In what way does life exist through death? Is not this as true in the moral as in the physical world? What does it teach? How rapidly do our bodies change? What are the three vital organs? 123. Name some of the wonders of the heart. 124-126. What is the lymphatic circulation? What is the thoracic duct? The lymph? The glands? What is the office of the lymphatics? What are the lacteals? Give some illustrations of the action of the lymphatics of the different organs. Should we use care in selecting wall paper? What is meant by the subcutaneous insertion of morphine? How do hibernating animals live during the winter? What is a congestion? Its cause? 127. What is blushing? Why does terror cause one to grow cold and pale? How is an inflammation caused? Name its four characteristics. 128. How may severe bleeding be stopped? How can you tell whether the blood comes from an artery or a vein? Why should you know this? What is the scrofula? What are "kernels"? 129, 130. How may a scrofulous tendency of the system be counteracted? What kinds of food stimulate this disease? What is the cause of a "cold"? Why does exposure sometimes cause a cold in the head, sometimes on the lungs, and at others bring on a rheumatic attack? Why is a cold dangerous? _Ans_. It weakens the system and paves the way for other diseases. What is the theory of treating a cold? Describe the method. What is catarrh? Cause? 131, 132. How is alcohol produced? Is alcohol present in domestic wines and home-brewed ales? Are they, then, harmless drinks? What is a ferment? (See also pp. 300, 301.) What is the difference between ferments, bacteria, microbes, and fungi? _Ans_. A few investigators still look upon the microorganisms known as bacteria and microbes as animal existences, but the larger part now concede them to be vegetable. 133. What is the effect of fermentation? What can you say concerning yeast? 134. Explain the process of making beer. Wine. What is distillation? 135, 136. Is there more than one kind of alcohol? What can you say of methyl alcohol? Amyl? Ethyl? Which is the ordinary alcohol of commerce? What is the peculiar effect of fusel oil? Is it often found in wines and spirits? Has alcohol any beneficial properties? 137, 138. Describe one of the striking effects of alcohol. What is the effect of alcohol on plant and animal life? 139, 140. What is the difference between the alcohol present in beer and cider, and that in gin and whiskey? Name another dangerous effect of alcoholic drinks. What business consideration should deter young men from liquor drinking? 141-143. Illustrate the general effect of alcohol upon the circulation. Upon the heart. Is alcohol a stimulant or a narcotic? Describe how alcohol becomes the "Genius of Degeneration." Explain what is meant by "Vascular Enlargement." 144, 145. Describe the effect of alcohol upon the membranes. Upon the blood. Does it render the blood thin or heavy? What is the difference between pure and alcoholized blood? 145-147. Describe the effect of alcohol upon the lungs. What form of consumption does it induce? Are liquor drinkers more or less liable to epidemic diseases? 314. How does the pulse felt by the finger correspond with the beat of the heart? Name some agencies that influence the pulse beat? Which part of the body has the most varied form of pulsation? 315. Compare the pulses of the wrist and brain in the sleeping and the waking states. How do catarrhal colds generally arise? How are they best cured? 316. What is said of the vitality of catarrh germs? What is a popular fallacy with regard to the care of sick rooms? Give Dr. Austin Flint's remarks in this connection. DIGESTION AND FOOD. 151. Why do we need food? Why will a person starve without food? Are the current stories of people who live without food to be relied upon? How much food is needed per day by an adult in active exercise? 152. How much in a year? How does this amount vary? Describe the body as a mold. As an eddy. What does food do for us? What does food contain? 153. How is this force set free? What force is this? How can it be turned into muscular motion, mental vigor, etc.? Do we then draw all our power from nature? What becomes of these forces when we are done with them? Do we destroy the force we use? _Ans_. No matter has been destroyed, so far as we know, since the creation, and force is equally indestructible. Compare our food to a tense spring. 154. What three kinds of food do we need? What is nitrogenous food? Name the common forms. What is the characteristic of nitrogenous food? Why called albuminous? What is carbonaceous food? Its two kinds? Constituents of sugar? Where are starch and gum ranked? Why? Use of carbonaceous food? What becomes of this heat? Composition of fat? How does fat compare with sugar in producing heat? 155. Name the other uses of carbonaceous food. From what kind of food does the body derive the greatest strength? Name the mineral matters which should be contained in our food. What can you say of the abundance and necessity of water? Ought we not to exercise great care in selecting the water we drink? [Footnote: Water which has passed through lead pipes is apt to contain salts of that metal, and is therefore open to suspicion. Metallic lined ice pitchers, galvanized-iron reservoirs, and many soda- water fountains, are liable to the same objection. (See pp. 317, 318.)] Does the character of our food influence the quantity of water we need? 156. What are the uses of the different minerals contained in food? Illustrate the importance of salt. Could a person live on one kind of food alone? Illustrate. 157. Describe the effect of living on lean meat. Show the necessity of a mixed diet. Illustrate. Show the need of digestion. Illustrate. 158. What is assimilation? Describe the general plan of digestion. What did Berzelius call digestion? Why? What amount of liquid is daily secreted by the alimentary canal? What is the alimentary canal? How is it lined? How does the amœba digest its food? 159. The hydra? Define secretion. Describe the saliva. How is it secreted? What is the amount? Its organic principle? Its use? How soon does it act? How long? What tends to check or increase the flow of saliva? 160. Describe the process of swallowing. The stomach. Its size. Its construction. What is the peristaltic movement? 162. What is the pylorus? For what does this open? What is the gastric juice? How abundant is it? To what is its acidity due? What organic principle does it contain? How is pepsin prepared? How is the flow of gastric juice influenced? 163. What is its use? Appearance of the food as it passes through the pylorus? Why is not the stomach itself digested? What is the construction of the intestines? How are the intestines divided? What is the duodenum? Why so called? What juices are secreted here? 164. What is the bile? Describe the liver. What is its weight? Its construction? _Ans_. It consists of a mass of polyhedral cells only 1/100 to 1/2000 of an inch in diameter, filling a mesh of capillaries. The capillaries carry the blood to and fro, and the cells secrete the bile. What is the cyst? What does the liver secrete from the blood besides the bile? Is the bile necessary to life? Illustrate. What is its use? 165. What is the pancreatic juice? Its organic principle? Its use? Appearance of the food when it leaves the duodenum? Describe the small intestine. What is absorption? In what two ways is the food absorbed? 166. Where does the process commence? How long does it last? Describe the lacteals. Of what general system do they form a part? What do the veins absorb? Where do they carry the food? How is it modified? 167. What is glycogen? Describe the complexity of the process of digestion. What length of time is required for digestion in the stomach? 168. May not food which requires little time in the stomach need more in the other organs, and _vice versa_? Tell the story of Alexis St. Martin. What time was required to digest an ordinary meal? Apples? Eggs, raw and cooked? Roast beef? Pork? Which is the king of the meats? What is the nutritive value of mutton? Lamb? How should it be cooked? Objection to pork? What is the trichina? 169. Should ham ever be eaten raw? Value of fish? Oysters? Milk? Cheese? Eggs? Bread? Brown bread? Are warm biscuit and bread healthful? Nutritive value of corn? 170. Of the potato? Of ripe fruits? Of coffee? To what is its stimulating property due? Its influence on the system? When should it be discarded? Should children use any stimulants? 171. Effects of tea? Influence of strong tea? What is the active principle of tea? Nutritive value of chocolate? What is its active principle? Story of Linnæus? How should tea be made? What is the effect of cooking food? What precaution in boiling meat? In roasting? Object of this high temperature? What precaution in making soup? Why is frying an unhealthful mode of cooking? 172. State the five evil results of rapid eating. What disease grows out of it? If one is compelled to eat a meal rapidly, as at a railroad station, what should he take? Why? Why does a child need more food proportionately than an old person? State the relation of waste to repair in youth, in middle, and in old age. What kind and quantity of food does a sedentary occupation require? What caution should students who have been accustomed to manual labor observe? Must a student starve himself? 173. Is there not danger of overeating? Would not an occasional abstinence from a meal be beneficial? Do not most people eat more than is for their good? How should the season regulate our diet? The climate? Illustrate. What does a natural appetite indicate? How are we to judge between a natural and an artificial longing? What does the craving of childhood for sugar indicate? [Footnote: It does not follow from this, however, that the free use of sugar in its separate form is desirable. The ordinary articles of vegetable food contain sugar (or starch, which in the body is converted into sugar), in large proportion; and there is good reason to believe that in its naturally combined form it is both more easily digested, and more available for the purposes of nutrition, than when crystallized. The ordinary sugar of commerce, moreover, derived from the sugar cane, is not capable of being directly applied to physiological purposes. Cane sugar is converted within the body into another kind of sugar, identical with that derived from the grape, before it can enter into the circuit of the vital changes.] 174. What is the effect upon the circulation of taking food? Should we labor or study just before or after a meal? Why not? What time should intervene between our meals? Is "lunching" a healthful practice? Eating heartily just before retiring? Is it never wise to eat at this time? (See p. 337.) Why should care be banished from the table? Will a regular routine of food be beneficial? 175, 176. Describe some of the wonders of digestion. What are the principal causes of dyspepsia? How may we avoid that disease? 177. What are the mumps? What care should be taken? Is alcohol a food? Illustrate. 178-187. Compare the action of alcohol with that of water. Is the alcohol taken into the stomach eliminated unchanged? Does alcohol contain any element needed by the body? What is the effect of alcohol upon the digestion? Will pepsin act in the presence of alcohol? What is the effect of alcohol upon the liver? What is "Fatty Degeneration"? What is the effect of alcohol upon the kidneys? Does alcohol impart heat to the body? Does it confer strength? What does Dr. Kane say? Describe Richardson's experiments. Tell what peculiar influence alcohol exerts. What is alcoholism? What is heredity? 317. What characteristics should good drinking water possess? Are these always proof of its purity? Will filters remove all danger of contamination? How may a river infect the entire population of a town? State how well water may become a dangerous drink. 318. Relate how cases of fever have been caused by carelessness in dairies. How should suspected water be treated? Describe a convenient portable filter. Tell how water is affected by foul air. 319. Tell how ice may breed disease. What caution should be observed in engaging ice for our summer supply? Illustrate the structure of the glandular coat of the stomach. 320. What is the office of the cells? Describe the life history of a cell. How does the stomach weep, and what is the character of its tears? 321. What is tyrotoxicon? Give Dr. Vaughan's experiments with cheese, milk, and ice cream. Tell how milk may be poisoned. 322. Compare the vigor of exclusively fish-eating with flesh-eating people. What is the peculiar value of fish as a diet? To what class of people is it best suited? Name examples. Describe the principles contained in coffee. What is the effect of caffeone? Of caffeine? Give some of the specific effects of coffee. How does tea differ from coffee? Describe the injurious effects of excessive tea drinking. 324. Compare theine and cocaine. Should children drink tea and coffee? 325. Give some causes of indigestion. Why are nervous people prone to dyspepsia? Give the comparative digestibility of various meats. 326. Describe how our food sustains our bodies. Illustrate the energy contained in one gramme of beef fat. Why is there danger in a "high- pressure" style of living? Illustrate. 327. State the effects of gluttony. Why is it unkindness to indulge inordinate appetites in children? What should be the rule in regard to their food? What effects would follow its observance? THE NERVOUS SYSTEM. 191. What are the organs of the nervous system? What is the general use of this system? How does it distinguish animals from plants? What are the vegetative functions? What is the gray matter? Its use? The white matter? Its use? 193. Describe the brain. What is its office? Its size? How does it vary? Illustrate. Name its two divisions. 194, 195. Describe the cerebrum. The convolutions. The membranes which bind the brain together. What can you say of the quantity of blood which goes to the brain? What does it show? What do the convolutions indicate? What is the use of the two halves of the brain? What theories have been advanced concerning it? Is every injury to the brain fatal? Illustrate. Compare the human brain with the brains of some animals. 196. What is the effect of removing the cerebrum? Describe the cerebellum. What is the arbor vitæ? What does this part of the brain control? What are the peculiar functions of the cerebellum? Give Dr. Bastian's remarks. 197. What is the effect of an injury to the cerebellum? Describe the spinal cord. What is the medulla oblongata? Describe the nerves. Is each part of the body supplied with its own nerve? Prove it. 198. What are the motory nerves? The sensory? When will motion be lost and feeling remain, and _vice versa?_ What is meant by a transfer of pain? Illustrate. 199. Name the three classes of nerves. What are the spinal nerves? Describe the origin of the spinal nerve. 199-201. What are the cranial nerves? How many pairs are there? Describe them. 201, 202. Describe the sympathetic system. What is its use? How does the brain control all the vital processes? What is meant by the crossing of the cords? What is the effect? What exception in the seventh pair of cranial nerves? 203, 204. What is reflex action? Give illustrations. Give instances of the unconscious action of the brain. [Footnote: The cerebellum has its unconscious action in the processes of respiration and in the involuntary movements which are made in response to the senses, as in winking, starting back at a sound, etc. The cerebrum acts automatically in oases familiar to all. A large part of our mental activity consists of this unconscious brain work. There are many cases in which the mind has obviously reasoned more clearly and more successfully in this automatic condition, when left entirely to itself, than when we have been cudgeling our brains, so to speak, to get the solution. Oliver Wendell Holmes has aptly expressed this fact. "We wish," he says, "to remember something in the course of conversation. No effort of the will can reach it; but we say, 'Wait a minute, and it will come to me,' and we go on talking. Some minutes later, the idea we are in search of comes all at once into the mind, delivered like a prepaid parcel, or like a foundling in a basket, laid at the door of consciousness. How it came there, we know not. The mind must have been at work, groping and feeling for it in the dark; it can not have come of itself. Yet, all the while, our consciousness, _so far as we are conscious of our consciousness_, was busy with other thoughts." Some interesting personal experiences upon this point are given in an article entitled "The Antechamber of Consciousness," by Francis Speir, Jr., in the _Popular Science Monthly_ for March, 1888.] Can there be feeling or motion in the lower limbs when the spinal cord is destroyed? What does the story told by Dr. John Hunter show? Give illustrations of the independent action of the spinal cord in animals. What are the uses of reflex action? 205. State its value in the formation of habits. How does the brain grow? What laws govern it? What must be the effect of constant light reading? Of overstudy or mental labor? 206. State the relation of sleep to repair and waste. How many hours does each person need? What kind of work requires most sleep? 206-208. What is the influence of sunlight on the body? Illustrate. Name some of the wonders of the brain. 208-213. What four stages are there in the effect of alcohol on the nervous system? Describe each. Does alcohol confer any permanent strength? What is the physiological effect of alcohol on the brain? On the mental and moral powers? What is the Delirium Tremens? Should a man be punished for a crime he commits while drunk? 214-218. What are the principal constituents of tobacco? What are its physiological effects? Who are most likely to escape injury? Is tobacco a food? What is its influence upon youth? Why are cigarettes specially injurious? What effect does tobacco have on the sensibilities? Name illustrations of the injurious effect of tobacco on young men. 219-221. How is opium obtained? What is its physiological effect? Which form of using it is most injurious? Can one give up the use of opium when he pleases? How do people sometimes take opium without knowing it? 221. What is the harmful influence of chloral hydrate? Describe its different physiological effects. 222. Compare its influence with that of alcohol. How is chloroform obtained? Does its use require great caution? Illustrate its effects. 223, 224. What is cocaine? What is its value? Its physiological effect? Its dangers? 331-333. What is the effect of extreme anger? Give the physiological explanation of this deterioration. What two organs particularly suffer? Illustrate. To what cause are many suicides referable? How can one secure a calm and tranquil life? What is the effect of forcing the brain in childhood? 334. Illustrate. How should a child be taught? 334, 335. Why should we not exhaust our energies to the last degree? What warnings does Nature give us? Do stimulants supply force? What is the effect of mental exhaustion? Which is the most common, overwork or worry? Most dangerous? What is worry? Its effect? What other causes often induce insanity? 336-338. State some curiosities of sleep. Some conditions necessary to sound and healthful slumber. How may we acquire the habit of early rising? 338, 339. Give some of the results of dungeon life. 339-347. What can you say of the growth and power of poison habits? Illustrate. How does physiological ignorance often cause intemperance? What is the usual result of a stimulant habit? In what virtue lies the peril of narcotics? Balance the good and the evil in their use. Illustrate how death often results from chloroform and chloral. What common result is worse than death? Compare the demoralization in the cases of the opium user and the alcohol drinker. What principle of heredity attaches to the use of opium? Give instances of deaths from tobacco, opium, etc. What can you say of cigarette smoking? Chloral hydrate? The bromides? Absinthe? Hasheesh? THE SPECIAL SENSES. 229, 230. What is a sense? Name the five senses. To what organ do all the senses minister? If the nerve leading to any organ of sense be cut, what would be the effect? [Footnote: Each, organ is adapted to receive a peculiar kind of impression. Hence we can not smell with, the eyes nor see with the nose. Thus, if the nerve communicating between the brain and any organ be destroyed, that means of knowledge is cut off.] Sometimes persons lose feeling in a limb, but retain motion; why is this? What is the sense of touch sometimes called? Describe the organ of touch. What are the papillæ? Where are they most abundant? [Footnote: If we apply the points of a compass blunted with cork to different parts of the body, we can distinguish the two points at one twenty-fourth of an inch apart on the tongue, one sixteenth, of an inch on the lips, one twelfth of an inch on the tips of the fingers, and one half inch on the great toe; while, if they are one inch on the cheek, and two inches on the back, they will scarcely produce a separate sensation.--HUXLEY.] What are the uses of this sense? What special knowledge do we obtain by it? Why do we always desire to handle any curious object? Can the sense of touch always be relied upon? Illustrate. What is the _tactus eruditus_? Tell how one sense can take the place of another. Give illustrations of the delicacy of touch possessed by the blind. 230-232. Describe the sense of taste. How can you see the papillæ of taste? What causes the velvety look of the tongue? Why do salt and bitter flavors induce vomiting? Why does an acid "pucker" the face? What substances are tasteless? Illustrate. Has sulphur any taste? Chalk? Sand? What is the use of this sense? Does it not also add to the pleasures of life? Why are the acts of eating, drinking, etc., thus made sources of happiness? 232, 233. Describe the organ of smell. State the intimate relation which exists between the senses of smell and taste. Name some common mistakes which occur in consequence. Must the object to be smelled touch the nose? What is the theory of smell? How do you account for the statement made in the note concerning musk and ambergris? What are the uses of this sense? Are agreeable odors healthful, and disagreeable ones unhealthful? 234-236. Describe the organ of hearing. Describe the external ear. What is the tympanum or drum of the ear? Describe the middle ear. Name the bones of the ear. Describe their structure. Describe the internal ear. By what other name is it known? What substances float in the liquid which fills the labyrinth? What is their use? Describe the fibers of Corti. What do they form? Use of this microscopic harp? Give the theory of sound. Where is the sound, in the external object or in the mind? Can there be any sound, then, where there is no mind? What advice is given concerning the care of the ear? How can insects be removed? Which sense would you rather lose, hearing or sight? Does not a blind person always excite more sympathy than a deaf one? How does the sight assist the hearing? [Footnote: In _hearing_, the attention is more or less characteristic. If we wish to distinguish a distant noise, or perceive a sound, the head inclines and turns in such a manner as to present the external ear in the direction of the sound, at the same time the eyes are fixed and partially closed. The movement of the lips of his interlocutor is the usual means by which the deaf man supplies the want of hearing; the eyes and the entire head, from its position, having a peculiar and painful expression of attention. In looking at the portrait of La Condamine, it was easily recognized as that of a deaf person. Even when hearing is perfect, the eyes act sometimes as auxiliaries to it. In order to understand an orator perfectly, it seems necessary to see him--the gestures and the expression of the face seeming to add to the clearness of the words. The lesson of a teacher can not be well understood if any obstacle is interposed between him and the eyes of the listening pupil. So that if a pupil's eyes wander, we know that he is not attentive.-- _Wonders of the Human Body_.] 236, 237. Describe the eye. Name the three coats of which it is composed. Is it a perfect sphere? _Ans_. The cornea projects in front, and the optic nerve at the back sticks out like a handle, while the ball itself has its longest diameter from side to side. How is the interior divided? Object of the crystalline lens? How is the crystalline lens kept in place? Describe the liquids which fill the eye. 238. What is the pupil? Describe the eyelids. Why is the inner side of the eyelid so sensitive? What is the cause of a black eye? Use of the eyelashes? Where are the oil glands located? What is their use? Describe the lachrymal gland. The lachrymal lake. What causes the overflow in old age? 239. Explain the structure of the retina. Use of the rods and cones. What is the blind spot? 240. Illustrate. What is the theory of sight? Illustrate. 241, 242. State the action of the crystalline lens. Its power of adaptation. Do children ever need spectacles? 243. What is the cataract? How cured? What is color blindness? Illustrate. What care should be taken of the eyes? Should one constantly lean forward over his book or work? What special care should nearsighted children take? By what carelessness may we impair our sight? 244. How is squinting caused? Cured? What care should be used after an illness? Should we ever read or write at twilight? Danger of reading upon the ears? What course should we take when objects get into the eye? How may they be removed? 245. Are "eyestones" useful? Why should we never use eyewashes except upon the advice of a competent physician? What rule should be observed with regard to the direction of the light when we are at work? Name some causes of near-sightedness. Remedies. 346. Give the account of Laura Bridgman. 347-350. Describe the anatomy of the nose. In what part of the nose is the function of smell performed? Why do we "sniff" when our attention is attracted by an odor? Give some experiments which illustrate the connection between smell, taste, and touch. Why should we retain our food in the mouth as long as possible? Of what use are gastronomic odors? 350. Why should a child's ear never be boxed? Illustrate. How can we detect inattention from deafness in a child? What should we consider in this respect? 351. Why should we avoid direct draughts in the ear? Explain the use of earwax. What common habit is very injurious? Why? 352, 353. What is the office of the Eustachian tube? Illustrate. 353, 354. Describe the action of the "eye curtain." Give experiments. What are "Purkinje's Figures"? Describe experiment. HEALTH AND DISEASE. 251-254. State some of the benefits of health. Contrast it with sickness. How were diseases formerly supposed to be caused? What remedies were used? What does modern science teach us to be the nature of disease? Give some illustrations showing how diseases may be prevented. Is it probable that the body was intended to give out in any one of its organs? What is the first step to be taken in the cure of a disease? What should be the object of medicine? What is now the chief dependence of the best physicians? What do you think concerning the common use of patent nostrums? Ought we not to use the greatest care in the selection of our physician? GLOSSARY. Ab do' men (_abdo_, I conceal). The largest cavity in the body, in which are hidden the intestines, stomach, etc. Ab sorb' ent (_ab_, from _sorbeo_, I suck up). Ac' e tab' u lum (_acetum_, vinegar). The socket for holding the head of the thigh bone, shaped like an ancient vinegar vessel. A ce' tic (_acetum_, vinegar). Ad' i pose. Fatty. Al bu' men (_albus_, white). A substance resembling the white of egg. Al bu' mi nous substances contain much albumen. Al' i men' ta ry. Pertaining to food. Al' ka line (-lin) substances neutralize acids. An' æs thet' ic. A substance that destroys the feeling of pain. A or' ta. The largest artery of the body. Ap' o plex y (pleks y). A disease marked by loss of sensation and voluntary motion. A' que ous (a'-kwe-us). Watery. A rach' noid (_arachne_, a spider; _eidos_, form). A membrane like a spider's web covering the brain. Ar' bor vi'tæ means "the tree of life." Ar' tery (_aer_, air; _tereo_, I contain). So named because after death the arteries contain air only, and hence the ancients supposed them to be air tubes leading through the body. Ar tic' u late (_articulo_, I form a joint). Ar tic' u la tion. A joint. As phyx' ia (-fix-i-a). Literally, no pulse; apparent death. As sim' i la' tion is the process of changing food into flesh, etc. At' las. So called because, as in ancient fable the god Atlas supported the globe on his shoulders, so in the body this bone bears the head. Au' di to ry Nerve. The nerve of hearing. Au' ri cle (-kl) (_auris_, ear) of the heart. So named from its shape. Bi' ceps. A muscle with two heads, or origins. Bi cus' pid. Tooth with two points; also a valve of the heart. Bron' chi (-ki). The two branches of the windpipe. Bron' chi al Tubes. Subdivisions of bronchi. Bur sa (a purse). Small sac containing fluid near a joint. Ca nine' (_canis_, a dog) teeth are like dog's teeth. Cap' il la ries (_capillus_, a hair). A system of tiny blood vessels. Car' bon. Pure charcoal. Car bon' ic Acid. A deadly gas given off by the lungs and by fires. Ca rot' ids (_karos_, lethargy). Arteries of the neck, so named because the ancients supposed them to be the seat of sleep. Car' pus. The wrist. Car' ti lage. Gristle. Cell. A minute sac, usually with soft walls and fluid contents. Cel' lu lar (_cellula_, a little cell). Full of cells. Cer' e bel' lum. The little brain. Cer' e brum. A Latin word meaning brain. Cer' vi cal. Relating to the neck. Chlo' ral (klo) Hy' drate. A drug used to induce sleep. Cho' roid. The second coat of the eye. Chyle (kile). A milky juice formed in digestion. Chyme (kime). From _chumos_, juice. Cir' cu la' tion. The course of the blood through the body. Cil' i a (the plural of _cilium_, an eyelash). Hair-like projections in the air passages. Clav' i cle (klav'-i-kl). From _clavis_, a key. Co ag' u la'tion. A clotting of blood. Coc' cyx (a cuckoo). A bony mass below the sacrum. Coch' le a. A Latin word meaning snail shell. See Ear Com' pound. A substance composed of two or more elements. Con ta' gious diseases are those caught by contact, the breath, etc. Con' trac til' i ty (_con_, together; _traho_, I draw). Con' vo lu' tion (_con_, together; _volvo_, I roll). Cor' ne a (_cornu_, a horn). A transparent, horn-like window in the eye. Cor' pus cle (kor'-pus-l). From a Latin word meaning a little body. It is applied to the disks of the blood. Cra' ni al. Relating to the skull. Crys'tal line (_crystallum_, a crystal). Cu ta' ne ous (_cutis_, skin). Pertaining to the skin. Cu' ti cle (ku'-ti-kl). From a Latin word meaning little skin. Cu' tis, the true skin. Den' tal (_dens, dentis_, a tooth). Di' a phragm (-fram). The muscle dividing the abdomen from the chest. Di as' to le (_diastello_, I put asunder). Dilation of the heart. Dis' lo ca' tion. A putting out of joint. Dor' sal (_dorsum_, the back). Duct. A small tube. Du o de' num (_duodeni_, twelve each). Du' ra Ma' ter (_durus_, hard; _mater_, mother). The outer membrane of the brain. Dys pep' si a is a difficulty of digestion E lim' i nate. To expel. Ep' idem' ic. A disease affecting a great number of persons at once. Ep' i der' mis. The cuticle. Ep' i glot' tis (_epi_, upon; _glottis_, the tongue). The lid of the windpipe. Ep' i the' li um. The outer surface of mucous or serous membranes. Eu sta' chi an (u-sta'-ki-an) Tube. So named from its discoverer, an Italian physician. Ex cre' tion. Waste particles thrown off by the excretory organs. Fer' men ta' tion. The process by which sugar is turned into alcohol. Fi' brin (_fibra_, a fiber). Fil' a ment (_filum_, a thread). Func' tion. See Organ. Gan' gli on (gang'-gli-on). From _ganglion_, a knot; plu. ganglia. Gas' tric (_gaster_, stomach). Glands (_glandz_). From _glans_, a Latin word meaning acorn. Their object, is to secrete in their cells some liquid from the blood. Glot' tis. The opening at the top of the larynx. Hu' me rus. The arm bone. Hu' mor. A Latin word meaning moisture. Hy' dro gen. The lightest gas known, and one of the elements of water. Hy' gi ene. From a Greek word meaning health. Hyp' o glos' sal. Literally "under the tongue"; a nerve of the tongue. In ci' sor (_incido_, I cut) teeth are cutting teeth. In' spi ra' tion (_in_ and _spiro_, I breathe in). In tes' tine (-tin). From _intus_, within. Lach' ry mal (_lachryma_, a tear). Pertaining to tears. Lac' te al (_lac_, _lactis_, milk). So called from the milky look of the chyle during digestion. La cu' na, plu. lacunæ (_lakos_, a hole). Cavities in the bone structure. Lar' ynx (lar'-inx). The upper part of the windpipe. Lig' a ments (_ligo_, I bind) tie bones together. Lu' bri cate. To oil in order to prevent friction. Lum' bar (_lumbus_, a loin). Pertaining to the loins. Lymph (limf). From _lympha_, pure water. Lym phat' ic (lim-fat-ik). Mas' ti ca' tion. The act of chewing. Me dul' la Ob lon ga' ta. The upper part of the spinal cord. Mam' brane. A thin skin, or tissue. Mes' en tery. The membrane by which the intestines are fastened to the spine. Met' a car' pal (_meta_, after; _karpos_, wrist). Met' a tar' sal (_meta_, after; _tarsos_, the instep). Mi' cro scope (_mikros_, small; _skopeo_, I see). Mo'lar (_mola_, a mill) teeth are the grinders. Morp' hine (_Morpheus_, the Greek god of sleep). Mo' tor. Giving motion. Mu' cous (-kus) Membrane. A thin tissue, or skin, covering the open cavities of the body. See Serous. Mu' cous. A fluid secreted by a membrane and serving to lubricate it. Mus' cle (mus-l). A bundle of fibers covered by a membrane. My o' pi a (_muo_, I contract; _ops_, the eye). Nar cot' ic. A drug producing sleep. Na' sal (na'-zal). From _nasus_, the nose. Nerve (neuron, a cord). Ni' tro gen Gas is the passive element of the air. Ni trog' e nous. Containing nitrogen. Nu tri' tion. The process by which the body is nourished. Œ soph' agus (e-sof'-a-gus). The gullet; literally, a "food-carrier." Ol fac' to ry. Pertaining to the smell. Or' gan. An organ is a portion of the body designed for a particular use, which is called its _function_; thus the heart circulates the blood. Os' se ous. Bone-like. Os' si fy (_ossa_, bones; _facio_, I make). Ox i da' tion. The process of combining with oxygen. Ox' y gen. The active element of the air. Pal' ate (_palatum_, the palate). Roof of the mouth. Pan' cre as (_pas_, all; _kreas_, flesh). An organ of digestion. Pa pil' la, plu. papillæ. Tiny cone-like projections. Pa ral' y sis. A disease in which one loses sensation, or the power of motion, or both. Pa rot' id (_para_, near; _ous_, _otos_, ear). One of the salivary glands. Pa tel' la (a little dish). The kneepan. Pec' to ral. Pertaining to the chest. Pep' sin (_pepto_, I digest). The chief constituent of the gastric juice. Per' i car' di um (_peri_, around; _kardia_, the heart). The membrane wrapping the heart. Per' i os' te um (_peri_, around; _osteon_, bone). The membrane around the bone. Per' i stal' tic (_peri_, round; _stallein_, to arrange). Applied to the worm-like movement of the alimentary canal. Phar' ynx (far'-inx). From _pharugx_, the throat. Pi' a Ma' ter (tender mother). See Brain. Pig' ment. A paint. Plas' ma (plaz'-ma). The nutritious fluid of the blood. Pleu' ra (plu'-ra). From _pleuar_, a rib. The membrane that lines the chest and wraps the lungs. Pres by o' pi a (_presbus_, old; _ops_, the eye). A defect in the eye common to old age. Proc' ess. A projection. Sometimes it retains its ordinary meaning of "operation." Py lo' rus (a gate). The doorway through which the food passes from the stomach. Pul' mo na ry (_pulmo_, the lungs). Pertaining to the lungs. Ra' di us. A Latin word meaning the spoke of a wheel, a ray, etc. Ram' i fy. To spread like the branches of a tree. Res' pi ra´ tion (_re_, again; _spiro_, I breathe). Act of breathing. Ret' i na (_rete_, a net). The expansion of the optic nerve in the eye. Sa' crum (sacred). So named, it is said, because this bone of the pelvis was anciently offered in sacrifice. Sa li' va. A Latin word meaning spittle; the fluid secreted by the salivary glands. Scap' u la. The shoulder blade. Scav' en ger. A street sweeper. Sele rot' ic (skie-rot'-ic). The outer coat of the eye. Se cre' tion (_secretum_, to separate). Sed' en ta ry persons are those who sit much. Sen' so ry Nerves. The nerves of feeling. Se' rous Membrane. A thin tissue, or skin, covering the cavities of the body that are not open to the external air. Se' rum. The thin part of the blood. Sub cla' vi an. Located under the clavicle. Sub lin' gual (_sub_, under: _lingua_, the tongue). The salivary gland located under the tongue. Sub max' il la ry (_sub_, under; _maxilla_, jawbone). The salivary gland located under the jaw. Syn o' vi a (_sun_, with; _oon_, egg). A fluid that lubricates the joints. Syn o' vi al Membrane packs the joints. Sys' to le (_sustello_, I contract). Contraction of the heart. Tem' po ral. An artery on the temple (_tempus_, time), so called because, as is said, the hair whitens first at that point. Ten' dons (_tendo_, I stretch). The cords conveying motion from the muscle to the bone. Tho' rax (a breastplate). The cavity containing the lungs, etc. Tib' ia. The shin-bone. Tis' sue. A general term applied to the textures of which the different organs are composed; osseous tissue forms bones. Tra' che a (tra'-ke-a). Means rough, alluding to the roughened surface of the windpipe. Tri' ceps. A muscle with three heads, or origins. Tri' cus' pid (_tres_, three; _cuspis_, point). A valve of the heart. Tym' pa num (a drum) of the ear. Vas' cu lar (_vasculum_, little vessel). Full of small blood vessels. Ven' tri cle (-kl). A cavity of the heart. Ver' te bra, plu. vertebræ (_verto_, I turn). A term applied to each one of the bones of the spine. Vil' lus (_villus_, tuft of hair), plu. villi. Vi' ti ate. To taint. To spoil. Vit' re ous (_vitrium_, glass). Glassy. Vo' mer (plowshare). A bone of the nose. 
30541	----	A TREATISE ON ANATOMY, PHYSIOLOGY, AND HYGIENE DESIGNED FOR COLLEGES, ACADEMIES, AND FAMILIES. BY CALVIN CUTTER, M.D. ----- WITH ONE HUNDRED AND FIFTY ENGRAVINGS. ----- REVISED STEREOTYPE EDITION. NEW YORK: CLARK, AUSTIN AND SMITH. CINCINNATI:--W. B. SMITH & CO. ST. LOUIS, MO.:--KEITH & WOODS. 1858. Entered according to Act of Congress, in the year 1852, by CALVIN CUTTER, M. D., In the Clerk's Office of the District Court of the District of Massachusetts. C. A. ALVORD, Printer, No. 15 Vandewater Street, N. Y. PREFACE. Agesilaus, king of Sparta, when asked what things boys should learn, replied, "Those which they will _practise_ when they become men." As health requires the observance of the laws inherent to the different organs of the human system, so not only boys, but girls, should acquire a knowledge of the laws of their organization. If sound morality depends upon the inculcation of correct principles in youth, equally so does a sound physical system depend on a correct physical education during the same period of life. If the teacher and parents who are deficient in moral feelings and sentiments, are unfit to communicate to children and youth those high moral principles demanded by the nature of man, so are they equally incompetent directors of the physical training of the youthful system, if ignorant of the organic laws and the physiological conditions upon which health and disease depend. For these reasons, the study of the structure of the human system, and the laws of the different organs, are subjects of interest to all,--the young and the old, the learned and the unlearned, the rich and the poor. Every scholar, and particularly every young miss, after acquiring a knowledge of the primary branches,--as spelling, reading, writing, and arithmetic,--should learn the structure of the human system, and the conditions upon which health and disease depend, as this knowledge will be required in _practice_ in after life. "It is somewhat unaccountable," says Dr. Dick, "and not a little inconsistent, that while we direct the young to look abroad over the surface of the earth, and survey its mountains, rivers, seas, and continents, and guide their views to the regions of the firmament, where they may contemplate the moons of Jupiter, the rings of Saturn, and thousands of luminaries placed at immeasurable distances, ... that we should never teach them _to look into themselves_; to consider their own corporeal structures, the numerous parts of which they are composed, the admirable functions they perform, the wisdom and goodness displayed in their mechanism, and the lessons of practical instruction which may be derived from such contemplations." Again he says, "One great practical end which should always be kept in view in the study of physiology, is the invigoration and improvement of the corporeal powers and functions, the preservation of health, and the prevention of disease." The design of the following pages is, to diffuse in the community, especially among the youth, a knowledge of Human Anatomy, Physiology, and Hygiene. To make the work clear and practical, the following method has been adopted:-- 1st. The structure of the different organs of the system has been described in a clear and concise manner. To render this description more intelligible, one hundred and fifty engravings have been introduced, to show the situation of the various organs. Hence the work may be regarded as an elementary treatise on anatomy. 2d. The functions, or uses of the several parts have been briefly and plainly detailed; making a primary treatise on human physiology. 3d. To make a knowledge of the structure and functions of the different organs _practical_, the laws of the several parts, and the conditions on which health depends, have been clearly and succinctly explained. Hence it may be called a treatise on the principles of hygiene, or health. To render this department more complete, there has been added the appropriate treatment for burns, wounds, hemorrhage from divided arteries, the management of persons asphyxiated from drowning, carbonic acid, or strangling, directions for nurses, watchers, and the removal of disease, together with an Appendix, containing antidotes for poisons, so that persons may know what _should be done_, and what _should not be done_, until a surgeon or physician can be called. In attempting to effect this in a brief elementary treatise designed for schools and families, it has not been deemed necessary to use vulgar phrases for the purpose of being understood. The appropriate scientific term should be applied to each organ. No more effort is required to learn the meaning of a _proper_, than an improper term. For example: a child will pronounce the word as readily, and obtain as correct an idea, if you say _lungs_, as if you used the word _lights_. A little effort on the part of teachers and parents, would diminish the number of vulgar terms and phrases, and, consequently, improve the language of our country. To obviate all objections to the use of proper scientific terms, a Glossary has been appended to the work. The author makes no pretensions to new discoveries in physiological science. In preparing the anatomical department, the able treatises of Wilson, Cruveilhier, and others have been freely consulted. In the physiological part, the splendid works of Carpenter, Dunglison, Liebig, and others have been perused. In the department of hygiene many valuable hints have been obtained from the meritorious works of Combe, Rivers, and others. We are under obligations to R. D. Mussey, M. D., formerly Professor of Anatomy and Surgery, Dartmouth College, N. H., now Professor of Surgery in the Ohio Medical College; to J. E. M'Girr, A. M., M. D., Professor of Anatomy, Physiology, and Chemistry, St. Mary's University, Ill.; to E. Hitchcock, Jr., A. M., M. D., Teacher of Chemistry and Natural History, Williston Seminary, Mass.; to Rev. E. Hitchcock, D. D., President of Amherst College, Mass., who examined the revised edition of this work, and whose valuable suggestions rendered important aid in preparing the manuscript for the present stereotype edition. We return our acknowledgments for the aid afforded by the Principals of the several Academies and Normal Schools who formed classes in their institutions, and examined the revised edition as their pupils progressed, thus giving the work the best possible test trial, namely, the recitation-room. To the examination of an intelligent public, the work is respectfully submitted by CALVIN CUTTER. WARREN, MASS., _Sept. 1, 1852_. TO TEACHERS AND PARENTS. As the work is divided into chapters, the subjects of which are complete in themselves, the pupil may commence the study of the structure, use, and laws of the several parts of which the human system is composed, by selecting such chapters as fancy or utility may dictate, without reference to their present arrangement,--as well commence with the chapter on the digestive organs as on the bones. The acquisition of a correct pronunciation of the technical words is of great importance, both in recitation and in conversation. In this work, the technical words interspersed with the text, have been divided into syllables, and the accented syllables designated. An ample Glossary of technical terms has also been appended to the work, to which reference should be made. It is recommended that the subject be examined in the form of _topics_. The questions in _Italics_ are designed for this method of recitation. The teacher may call on a pupil of the class to describe the anatomy of an organ from an anatomical outline plate; afterwards call upon another to give the physiology of the part, while a third may state the hygiene, after which, the questions at the bottom of the page may be asked promiscuously, and thus the detailed knowledge of the subject possessed by the pupils will be tested. At the close of the chapters upon the Hygiene of the several portions of the system, it is advised that the instructor give a lecture reviewing the anatomy, physiology, and hygiene, of the topic last considered. This may be followed by a general examination of the class upon the same subject. By this course a clear and definite knowledge of the mutual relation of the Anatomy, Physiology, and Hygiene, of different parts of the human body, will be presented. We also suggest the utility of the pupils' giving analogous illustrations, examples, and observations, where these are interspersed in the different chapters, not only to induce inventive thought, but to discipline the mind. To parents and others we beg leave to say, that about two thirds of the present work is devoted to a concise and practical description of the uses of the important organs of the human body, and to show how such information may be usefully applied, both in the preservation of health, and the improvement of physical education. To this have been added directions for the treatment of those accidents which are daily occurring in the community, making it a treatise proper and profitable for the FAMILY LIBRARY, as well as the school-room. CONTENTS. Chapter. Page. 1. General Remarks, 13 2. Structure of Man, 17 3. Chemistry of the Human Body, 25 4. Anatomy of the Bones, 29 5. Anatomy of the Bones, continued, 39 6. Physiology of the Bones, 48 7. Hygiene of the Bones, 53 8. Anatomy of the Muscles, 64 9. Physiology of the muscles, 76 10. Hygiene of the Muscles, 85 11. Hygiene of the Muscles, continued, 96 12. Anatomy of the Teeth, 105 12. Physiology of the Teeth, 109 12. Hygiene of the Teeth, 110 13. Anatomy of the Digestive Organs, 113 14. Physiology of the Digestive Organs, 124 15. Hygiene of the Digestive Organs, 129 16. Hygiene of the Digestive Organs, continued, 142 17. Anatomy of the Circulatory Organs, 154 18. Physiology of the Circulatory Organs, 164 19. Hygiene of the Circulatory Organs, 172 20. Anatomy of the Lymphatic Vessels, 181 20. Physiology of the Lymphatic Vessels, 183 20. Hygiene of the Lymphatic Vessels, 188 21. Anatomy of the Secretory Organs. 192 21. Physiology of the Secretory Organs, 193 21. Hygiene of the Secretory Organs, 197 22. Nutrition, 200 22. Hygiene of Nutrition, 205 23. Anatomy of the Respiratory Organs, 209 24. Physiology of the Respiratory Organs, 217 25. Hygiene of the Respiratory Organs, 228 26. Hygiene of the Respiratory Organs, continued, 239 27. Animal Heat, 252 28. Hygiene of Animal Heat, 261 29. Anatomy of the Vocal Organs, 268 29. Physiology of the Vocal Organs, 272 30. Hygiene of the Vocal Organs, 274 31. Anatomy of the Skin, 282 32. Physiology of the Skin, 293 33. Hygiene of the Skin, 301 34. Hygiene of the Skin, continued, 311 35. Appendages of the Skin, 322 36. Anatomy of the Nervous System, 327 37. Anatomy of the Nervous System, continued, 340 38. Physiology of the Nervous System, 346 39. Hygiene of the Nervous System, 358 40. Hygiene of the Nervous System, continued, 368 41. The Sense of Touch, 378 42. Anatomy of the Organs of Taste, 384 42. Physiology of the Organs of Taste, 386 43. Anatomy of the Organs of Smell, 389 43. Physiology of the Organs of Smell, 391 44. Anatomy of the Organs of Vision, 394 45. Physiology of the Organs of Vision, 404 45. Hygiene of the Organs of Vision, 410 46. Anatomy of the Organs of Hearing, 414 47. Physiology of the Organs of Hearing, 420 47. Hygiene of the Organs of Hearing, 422 48. Means of preserving the Health, 425 49. Directions for Nurses, 432 - - - - - APPENDIX, 439 GLOSSARY, 451 INDEX, 463 ANATOMY, &c. CHAPTER I. GENERAL REMARKS. 1. ANATOMY is the science which treats of the structure and relations of the different parts of animals and plants. 2. It is divided into _Vegetable_ and _Animal_ anatomy. The latter of these divisions is subdivided into _Human_ anatomy, which considers, exclusively, human beings; and _Comparative_ anatomy, which treats of the mechanism of the lower orders of animals. 3. PHYSIOLOGY treats of the functions, or uses of the organs of animals and plants. Another definition is, "the science of life." 4. This is also divided into _Vegetable_ and _Animal_ physiology, as it treats of the vegetable or animal kingdom; and into _Human_ and _Comparative_ physiology, as it describes the vital functions of man or the inferior animals. 5. HYGIENE is the art or science of maintaining health, or a knowledge of those laws by which health may be preserved. 6. The kingdom of nature is divided into _organic_ and _inorganic_ bodies. Organic bodies possess organs, on whose action depend their growth and perfection. This division includes animals and plants. Inorganic bodies are devoid of organs, or instruments of life. In this division are classed the earths, metals, and other minerals. -=-=-=-=-=-=-=-=-=-=-=-= 1. What is anatomy? 2. How is it divided? How is the latter division subdivided? 3. What is physiology? Give another definition. 4. How is physiology divided? Give a subdivision. 5. What is hygiene? 6. Define organic bodies. -=-=-=-=-=-=-=-=-=-=-=-= 7. In general, organic matter differs so materially from inorganic, that the one can readily be distinguished from the other. In the organic world, every individual of necessity springs from some _parent, or immediate producing agent_; for while inorganic substances are formed by chemical laws alone, we see no case of an animal or plant coming into existence by accident or chance, or chemical operations. 8. Animals and plants _are supported by means of nourishment_, and die without it. They also increase in size _by the addition of new particles of matter to all parts of their substances_; while rocks and minerals grow only by additions to their surfaces. 9. "Organized bodies always present a combination of both solids and fluids;--of solids, differing in character and properties, arranged into organs, and these endowed with functional powers, and so associated as to form of the whole a single system;--and of fluids, contained in these organs, and holding such relation to the solids that the existence, nature, and properties of both mutually and necessarily depend on each other." 10. Another characteristic is, that organic substances have a _certain order of parts_. For example, plants possess organs to gain nourishment from the soil and atmosphere, and the power to give strength and increase to all their parts. And animals need not only a digesting and circulating apparatus, but organs for breathing, a nervous system, &c. -=-=-=-=-=-=-=-=-=-=-=-= 6. Define inorganic bodies. 7. What is said of the difference, in general, between organic and inorganic bodies? 8. What of the growth of organic and inorganic bodies? 9. What do organized bodies always present? 10. Give another characteristic of organized substances. -=-=-=-=-=-=-=-=-=-=-=-= 11. _Individuality_ is an important characteristic. For instance, a large rock may be broken into a number of smaller pieces, and yet every fragment will be rock; but if an organic substance be separated into two or more divisions, neither of them can be considered an individual. Closely associated with this is the power of _life_, or _vitality_, which is the most distinguishing characteristic of organic structure; since we find nothing similar to this in the inorganic creation. 12. _The distinction between plants and animals_ is also of much importance. _Animals grow proportionally in all directions_, while plants grow upwards and downwards from a collet only. The _food_ of animals is _organic_, while that of plants is _inorganic_; the latter feeding entirely upon the elements of the soil and atmosphere, while the former subsist upon the products of the animal and vegetable kingdoms. The size of the vegetable is in most cases limited only by the duration of existence, as a tree continues to put forth new branches during each period of its life, while the animal, at a certain time of life, attains the average size of its species. 13. One of the most important distinctions between animals and plants, is _the different effects of respiration_. Animals consume the oxygen of the atmosphere, and give off carbonic acid; while plants take up the carbonic acid, and restore to animals the oxygen, thus affording an admirable example of the principle of compensation in nature. 14. But the decisive distinctions between animals and plants are _sensation_ and _voluntary motion_, the power of acquiring a knowledge of external objects through the senses, and the ability to move from place to place at will. These are the characteristics which, in their fullest development in man, show intellect and reasoning powers, and thereby in a greater degree exhibit to us the wisdom and goodness of the Creator. -=-=-=-=-=-=-=-=-=-=-=-= 11. What is said of the individuality of organized and inorganized bodies? What is closely associated with this? 12. Give a distinction between animals and plants as regards growth. The food of animals and plants. What is said in respect to size? 13. What important distinction in the effects of respiration of animals and plants? 14. What are the decisive distinctions between animals and plants? -=-=-=-=-=-=-=-=-=-=-=-= 15. DISEASE, which consists in an unnatural condition of the bodily organs, is in most cases under the control of fixed laws, which we are capable of understanding and obeying. Nor do diseases come by chance; they are penalties for violating physical laws. If we carelessly cut or bruise our flesh, pain and soreness follow, to induce us to be more careful in the future; or, if we take improper food into the stomach, we are warned, perhaps immediately by a friendly pain, that we have violated an organic law. 16. Sometimes, however, the penalty does not directly follow the sin, and it requires great physiological knowledge to be able to trace the effect to its true cause. If we possess good constitutions, we are responsible for most of our sickness; and bad constitutions, or hereditary diseases, are but the results of the same great law,--the iniquities of the parents being visited on the children. In this view of the subject, how important is the study of physiology and hygiene! For how can we expect to obey laws which we do not understand? -=-=-=-=-=-=-=-=-=-=-=-= 15. What is said of disease? 16. Why is the study of physiology and hygiene important? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER II. STRUCTURE OF MAN, 17. In the structure of the human body, there is a union of fluids and solids. These are essentially the same, for the one is readily changed into the other. There is no fluid that does not contain solid matter in solution, and no solid matter that is destitute of fluid. 18. In different individuals, and at different periods of life the proportion of fluids and solids varies. In youth, the fluids are more abundant than in advanced life. For this reason, the limbs in childhood are soft and round, while in old age they assume a hard and wrinkled appearance. 19. The fluids not only contain the materials from which every part of the body is formed, but they are the medium for conveying the waste, decayed particles of matter from the system. They have various names, according to their nature and function; as, the blood, and the bile. 20. The solids are formed from the fluids, and consequently they are reduced, by chemical analysis, to the same ultimate elements. The particles of matter in solids are arranged variously; sometimes in _fi´bres_, (threads,) sometimes in _lam´i-næ_, (plates,) sometimes homogeneously, as in basement membranes. (Appendix A.) 21. The parts of the body are arranged into _Fi´bres_, _Fas-cic´u-li_, _Tis´sues_, _Or´gans_, _Ap-pa-ra´tus-es_, and _Sys´tems_. -=-=-=-=-=-=-=-=-=-=-=-= 17. What substances enter into the structure of the human body? Are they essentially the same? 18. What is said of these substances at different periods of life? 19. What offices do the fluids of the system perform? 20. What is said of the solids? How are the particles of matter arranged in solids? 21. Give an arrangement of the parts of the body. -=-=-=-=-=-=-=-=-=-=-=-= 22. A FIBRE is a thread of exceeding fineness. It is either cylindriform or flattened. 23. A FASCICULUS is the term applied to several fibres united. Its general characteristics are the same as fibres. 24. A TISSUE is a term applied to several different solids of the body. 25. An ORGAN is composed of tissues so arranged as to form an instrument designed for action. The action of an organ is called its _function_, or use. _Example._ The liver is an organ, and the secretion of the bile from the blood is one of its functions.[1] [1] Where examples and observations are given or experiments suggested, let the pupil mention other analogous ones. 26. An APPARATUS is an assemblage of organs designed to produce certain results. _Example._ The digestive apparatus consists of the teeth, stomach, liver, &c., all of which aid in the digestion of food. [Illustration: Fig. 2. Represents a portion of broken muscular fibre of animal life, (magnified about seven hundred diameters.)] 27. The term SYSTEM is applied to an assemblage of organs arranged according to some plan, or method; as the nervous system, the respiratory system. -=-=-=-=-=-=-=-=-=-=-=-= 22. Define a fibre. 23. Define a fasciculus. 24. Define a tissue. 25. Define an organ. What is the action of an organ called? Give examples. _Mention other examples._ 26. What is an apparatus? Give an example 27. How is the term system applied? -=-=-=-=-=-=-=-=-=-=-=-= 28. A TISSUE is a simple form of organized animal substance. It is flexible, and formed of fibres interwoven in various ways; as, the cellular tissue. 29. However various all organs may appear in their structure and composition, it is now supposed that they can be reduced to a few tissues; as, the _Cel´lu-lar_, _Os´se-ous_, _Mus´cu-lar_, _Mu´cous_, _Ner´vous_, &c. (Appendix B.) 30. The CELLULAR TISSUE,[2] now called the _areolar tissue_, consists of small fibres, or bands, interlaced in every direction, so as to form a net-work, with numerous interstices that communicate freely with each other. These interstices are filled, during life, with a fluid resembling the serum of blood. The use of the areolar tissue is to connect together organs and parts of organs, and to envelop, fix, and protect the vessels and nerves of organs. [2] The _Cellular_, _Serous_, _Dermoid_, _Fibrous_, and _Mucous tissues_ are very generally called _membranes_. [Illustration: Fig. 3. Arrangement of fibres of the cellular tissue magnified one hundred and thirty diameters.] -=-=-=-=-=-=-=-=-=-=-=-= 28. What is a tissue? 29. What is said respecting the structure and composition of the various organs? Name the primary membranes. 30. Describe the cellular tissue. How are the cells imbedded in certain tissues? Give observation 1st, relative to the cellular tissue. -=-=-=-=-=-=-=-=-=-=-=-= _Observations._ 1st. When this fluid becomes too great in quantity, in consequence of disease, the patient labors under general dropsy. The swelling of the feet when standing, and their return to a proper shape during the night, so often noticed in feeble persons, furnish a striking proof both of the existence and peculiarity of this tissue, which allows the fluid to flow from cell to cell, until it settles in the lower extremities. 2d. The free communication between the cells is still more remarkable in regard to air. Sometimes, when an accidental opening has been made from the air-cells of the lungs into the contiguous cellular tissue, the air in respiration has penetrated every part until the whole body is so inflated as to occasion suffocation. Butchers often avail themselves of the knowledge of this fact, and inflate their meat to give it a fat appearance. 31. "Although this tissue enters into the composition of all organs, it never loses its own structure, nor participates in the functions of the organ of which it forms a part. Though present in the nerves, it does not share in their sensibility; and though it accompanies every muscle and every muscular fibre, it does not partake of the irritability which belongs to these organs." 32. Several varieties of tissue are formed from the cellular; as, the _Se´rous_, _Der´moid_, _Fi´brous_, and several others. 33. The SEROUS TISSUE lines all the closed, or sac-like cavities of the body; as, the chest, joints, and abdomen. It not only lines these cavities, but is reflected, and invests the organs contained in them. The liver and the lungs are thus invested. This membrane is of a whitish color, and smooth on its free surfaces. These surfaces are kept moist, and prevented from adhering by a _se´rous_ fluid, which is separated from the blood. The use of this membrane is to separate organs and also to facilitate the movement of one part upon another, by means of its moist, polished surfaces. -=-=-=-=-=-=-=-=-=-=-=-= Give observation 2d. 31. What is said of the identity of this tissue? 32. Name the varieties of tissue formed from the cellular. 33. Where is the serous tissue found? What two offices does it perform? Give its structure. What is the use of this membrane? -=-=-=-=-=-=-=-=-=-=-=-= 34. The DERMOID TISSUE covers the outside of the body. It is called the _cu´tis_, (skin.) This membrane is continuous with the mucous at the various orifices of the body, and in these situations, from the similarity of their structure, it is difficult to distinguish between them. _Observations._ 1st. In consequence of the continuity and similarity of structure, there is close sympathy between the mucous and dermoid membranes. If the functions of the skin are disturbed, as by a chill, it will frequently cause a catarrh, (cold,) or diarrhoea. Again, in consequence of this intimate sympathy, these complaints can be relieved by exciting a free action in the vessels of the skin. 2d. It is no uncommon occurrence that diseased or irritated conditions of the mucous membrane of the stomach or intestines produce diseases or irritations of the skin, as is seen in the rashes attendant on dyspepsia, and eating certain species of fish. These eruptions of the skin can be relieved by removing the diseased condition of the stomach. 35. The FIBROUS TISSUE consists of longitudinal, parallel fibres, which are closely united. These fibres, in some situations, form a thin, dense, strong membrane, like that which lines the internal surface of the skull, or invests the external surface of the bones. In other instances, they form strong, inelastic bands, called _lig´a-ments_, which bind one bone to another. This tissue also forms _ten´dons_, (white cords,) by which the muscles are attached to the bones. _Observation._ In the disease called rheumatism, the fibrous tissue is the part principally affected; hence the joints, where this tissue is most abundant, suffer most from this affection. -=-=-=-=-=-=-=-=-=-=-=-= 34. Describe the dermoid tissue. What is said of the sympathy between the functions of the skin and mucous membrane? Give another instance of the sympathy between these membranes. 35. Of what does the fibrous tissue consist? How do these appear in some situations? How in others? What tissue is generally affected in rheumatism? -=-=-=-=-=-=-=-=-=-=-=-= 36. The ADIPOSE TISSUE is so arranged as to form distinct bags, or cells. These contain a substance called _fat_. This tissue is principally found beneath the skin, abdominal muscles, and around the heart and kidneys; while none is found in the brain, eye, ear, nose, and several other organs. _Observation._ In those individuals who are corpulent, there is in many instances, a great deposit of this substance. This tissue accumulates more readily than others when a person becomes gross, and is earliest removed when the system emaciates, in acute or chronic diseases. Some of the masses become, in some instances, enlarged. These enlargements are called _adipose_, or _fatty tumors_. [Illustration: Fig. 4. 1, A portion of the adipose tissue. 2, 2, 2, Minute bags containing fat. 3, A cluster of these bags, separated and suspended.] 37. The CARTILAGINOUS TISSUE is firm, smooth, and highly elastic. Except bone, it is the hardest part of the animal frame. It tips the ends of the bones that concur in forming a joint. Its use is to facilitate the motion of the joints by its smooth surface, while its elastic character diminishes the shock that would otherwise be experienced if this tissue were inelastic. -=-=-=-=-=-=-=-=-=-=-=-= 36. Describe the adipose tissue. Where does this tissue principally exist? Give observation in regard to the adipose tissue. 37. Describe the cartilaginous tissue. What is its use? -=-=-=-=-=-=-=-=-=-=-=-= 38 The OSSEOUS TISSUE, in composition and arrangement of matter, varies at different periods of life, and in different bones. In some instances, the bony matter is disposed in plates, while in other instances, the arrangement is cylindrical. Sometimes, the bony matter is dense and compact; again, it is spongy, or porous. In the centre of the long bones, a space is left which is filled with a fatty substance, called _mar´row_. _Observation._ Various opinions exist among physiologists in regard to the use of marrow. Some suppose it serves as a reservoir of nourishment, while others, that it keeps the bones from becoming dry and brittle. The latter opinion, however, has been called in question, as the bones of the aged man contain more marrow than those of the child, and they are likewise more brittle. [Illustration: Fig. 5. A section of the femur, (thigh-bone.) 1, 1, The extremities, showing a thin plate of compact texture, which covers small cells, that diminish in size, but increase in number, as they approach the articulation. 2, 2, The walls of the shaft, which are very firm and solid. 3, The cavity that contains the marrow.] 39. The MUSCULAR TISSUE is composed of many fibres, that unite to form fasciculi, each of which is enclosed in a delicate layer of cellular tissue. Bundles of these fasciculi constitute a muscle. _Observation._ A piece of boiled beef will clearly illustrate the arrangement of muscular fibre. -=-=-=-=-=-=-=-=-=-=-=-= 38. What is said of the osseous tissue? How is the bony matter arranged in different parts of the animal frame? What is said of the use of marrow? 39. Of what is the muscular tissue composed? How may the arrangement of muscular fibre be illustrated? -=-=-=-=-=-=-=-=-=-=-=-= 40. The MUCOUS TISSUE differs from the serous by its lining all the cavities which communicate with the air. The nostrils, the mouth, and the stomach afford examples. The external surface of this membrane, or that which is exposed to the air, is soft, and bears some resemblance to the downy rind of a peach. It is covered by a viscid fluid called _mu´cus_. This is secreted by small _gland-cells_, called _ep-i-the´li-a_, or secretory cells of the mucous membrane. The use of this membrane and its secreted mucus is to protect the inner surface of the cavities which it lines. _Observation._ A remarkable sympathy exists between the remote parts of the mucous membrane. Thus the condition of the stomach may be ascertained by an examination of the tongue. 41. The NERVOUS TISSUE consists of soft, pulpy matter, enclosed in a sheath, called _neu-ri-lem´a_. This tissue consists of two substances. The one, of a pulpy character and gray color, is called _cin-e-ri´tious_, (ash-colored.) The other, of a fibrous character and white, is named _med´ul-la-ry_, (marrow-like.) In every part of the nervous system both substances are united, with the exception of the nervous fibres and filaments, which are solely composed of the medullary matter enclosed in a delicate sheath. -=-=-=-=-=-=-=-=-=-=-=-= 40. How does the mucous differ from the serous tissue? What is the appearance of the external surface of this membrane? Where is the mucus secreted? What is the use of this membrane? 41. Of what does the nervous tissue consist? Describe the two substances that enter into the composition of the nervous tissue. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER III CHEMISTRY OF THE HUMAN BODY. 42. An ULTIMATE ELEMENT is the simplest form of matter with which we are acquainted; as gold, iron, &c. 43. These elements are divided into _metallic_ and _non-metallic_ substances. The metallic substances are _Po-tas´si-um_, _So´di-um_, _Cal´ci-um_, _Mag-ne´si-um_, _A-lu´min-um_, _I´ron_, _Man´ga-nese_, and _Cop´per_. The non-metallic substances are _Ox´y-gen_, _Hy´dro-gen_, _Car´bon_, _Ni´tro-gen_, _Si-li´-ci-um_, _Phos´phor-us_, _Sul´phur_, _Chlo´rine_, and a few others. 44. POTASH (potassium united with oxygen) is found in the blood, bile, perspiration, milk, &c. 45. SODA (sodium combined with oxygen) exists in the muscles, and in the same fluids in which potash is found. 46. LIME (calcium combined with oxygen) forms the principal ingredient of the bones. The lime in them is combined with phosphoric and carbonic acid. 47. MAGNESIA (magnesium combined with oxygen) exists in the bones, brain, and in some of the animal fluids; as milk. 48. SILEX (silicium combined with oxygen) is contained in the hair and in some of the secretions. 49. IRON forms the coloring principle of the red globules of the blood, and is found in every part of the system. _Observation._ As metallic or mineral substances enter into the ultimate elements of the body, the assertion that all minerals are poisonous, however small the quantity, is untrue. -=-=-=-=-=-=-=-=-=-=-=-= 42. What is an ultimate element? Give examples. 43. How are they divided? Name the metallic substances. Name the non-metallic substances. 44. What is said of potash? 45. Of soda? 46. Of lime? 47. Of magnesia? 48. Of silex? 49. What forms the coloring principle of the blood? What is said of mineral substances? -=-=-=-=-=-=-=-=-=-=-=-= 50. OXYGEN is contained in all the fluids and solids of the body. It is almost entirely derived from the inspired air and water. It is expelled in the form of carbonic acid and water from the lungs and skin. It is likewise removed in the other secretions. 51. HYDROGEN is found in all the fluids and in all the solids of the body. It is derived from the food, as well as from water and other drinks. It exists in the greatest abundance in the impure, dark-colored blood of the system. It is removed by the agency of the kidneys, skin, lungs, and other excretory organs. 52. CARBON is an element in the oil, fat, albumen, fibrin, gelatin, bile, and mucus. This element likewise exists in the impure blood in the form of carbonic acid gas. Carbon is obtained from the food, and discharged from the system by the secretions and respiration. 53. NITROGEN is contained in most animal matter, but is most abundant in fibrin. It is not contained in fat and a few other substances. _Observation._ The peculiar smell of animal matter when burning is owing to nitrogen. This element combined with hydrogen forms _am-mo´ni-a_, (hartshorn,) when animal matter is in a state of putrefaction. 54. PHOSPHORUS is contained in many parts of the system, but more particularly in the bones. It is generally found in combination with oxygen, forming _phosphoric acid_. The phosphoric acid is usually combined with alkaline bases; as lime in the bones, forming phosphate of lime. 55. SULPHUR exists in the bones, muscles, hair, and nails. It is expelled from the system by the skin and intestines. 56. CHLORINE is found in the blood, gastric juice, milk, perspiration, and saliva. -=-=-=-=-=-=-=-=-=-=-=-= 50. What is said of oxygen? 51. Of hydrogen? 52. What is said of carbon? 53. Of nitrogen? How is ammonia formed? 54. What is said of phosphorus? 55. What is said of sulphur? 56. Of chlorine? -=-=-=-=-=-=-=-=-=-=-=-= 57. PROXIMATE ELEMENTS are forms of matter that exist in organized bodies in abundance, and are composed chiefly of oxygen, hydrogen, carbon, and nitrogen, arranged in different proportions. They exist already formed, and may be separated in many instances, by heat or mechanical means. The most important compounds are _Al-bu´men_, _Fi´brin_, _Gel´a-tin_, _Mu´cus_, _Fat_, _Ca´se-ine_, _Chon´drine_, _Lac´tic acid_, and _Os´ma-zome_. 58. ALBUMEN is found in the body, both in a fluid and solid form. It is an element of the skin, glands, hair, and nails, and forms the principal ingredient of the brain. Albumen is without color, taste, or smell, and it coagulates by heat, acids, and alcohol. _Observation._ The white of an egg is composed of albumen, which can be coagulated or hardened by alcohol. As albumen enters so largely into the composition of the brain, is not the impaired intellect and moral degradation of the inebriate attributable to the effect of alcohol in hardening the albumen of this organ? 59. FIBRIN exists abundantly in the blood, chyle, and lymph. It constitutes the basis of the muscles. Fibrin is of a whitish color, inodorous, and insoluble in cold water. It differs from albumen by possessing the property of coagulating at all temperatures. _Observation._ Fibrin may be obtained by washing the thick part of blood with cold water; by this process, the red globules, or coloring matter, are separated from this element. 60. GELATIN is found in nearly all the solids, but it is not known to exist in any of the fluids. It forms the basis of the cellular tissue, and exists largely in the skin, bones, ligaments, and cartilages. -=-=-=-=-=-=-=-=-=-=-=-= 57. What are proximate elements? Do they exist already formed in organized bodies? Name the most important compounds. 58. What is said of albumen? Give observation relative to this element. 59. Of fibrin? How does albumen differ from fibrin? How can fibrin be obtained? 60. What is said of gelatin? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Gelatin is known from other organic principles by its dissolving in warm water, and forming "jelly." When dry, it forms the hard, brittle substance, called _glue_. Isinglass, which is used in the various mechanical arts, is obtained from the sounds of the sturgeon. 61. MUCUS is a viscid fluid secreted by the gland-cells, or epithelia. Various substances are included under the name of mucus. It is generally alkaline, but its true chemical character is imperfectly understood. It serves to moisten and defend the mucous membrane. It is found in the cuticle, brain, and nails; and is scarcely soluble in water, especially when dry. (Appendix C.) 62. OSMAZOME is a substance of an aromatic flavor. It is of a yellowish-brown color, and is soluble both in water and alcohol, but does not form a jelly by concentration. It is found in all the fluids, and in some of the solids; as the brain. _Observation._ The characteristic odor and taste of soup are owing to osmazome. 63. There are several acids found in the human system; as the _A-ce´tic_, _Ben-zo´ic_, _Ox-al´ic_, _U´ric_, and some other substances, but not of sufficient importance to require a particular description. -=-=-=-=-=-=-=-=-=-=-=-= How is it known from other organic principles? 61. What is said of mucus? 62. Of osmazome? To what are the taste and odor of soup owing? 63. What acids are found in the system? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER IV. THE BONES. 64. The bones are firm and hard, and of a dull white color. In all the higher orders of animals, among which is man, they are in the interior of the body, while in lobsters, crabs, &c., they are on the outside, forming a case which protects the more delicate parts from injury. 65. In the mechanism of man, the variety of movements he is called to perform requires a correspondent variety of component parts, and the different bones of the system are so admirably adapted to each other, that they admit of numerous and varied motions. 66. When the bones composing the skeleton are united by natural ligaments, they form what is called a _natural skeleton_, when united by wires, what is termed an _artificial skeleton_. 67. The elevations, or protuberances, of the bones are called _proc´es-ses_, and are, generally, the points of attachment for the muscles and ligaments. ANATOMY OF THE BONES. 68. The BONES are composed of both animal and earthy matter. The earthy portion of the bones gives them solidity and strength, while the animal part endows them with vitality. -=-=-=-=-=-=-=-=-=-=-=-= 64. What is said of the bones? 65. Is there an adaptation of the bones of the system to the offices they are required to perform? 66. What is a natural skeleton? What an artificial? 67. What part of the bones are called processes? 68-73. _Give the structure of the bones._ 68. Of what are the bones composed? What are the different uses of the component parts of the bones? -=-=-=-=-=-=-=-=-=-=-=-= _Experiments._ 1st. To show the earthy without the animal matter, burn a bone in a clear fire for about fifteen minutes, and it becomes white and brittle, because the gelatin, or animal matter of the bone, has been destroyed. 2d. To show the animal without the earthy matter of the bones, immerse a slender bone for a few days in a weak acid, (one part muriatic acid and six parts water,) and it can then be bent in any direction. In this experiment, the acid has removed the earthy matter, (carbonate and phosphate of lime,) yet the form of the bone is unchanged. 69. The bones are formed from the blood, and are subjected to several changes before they are perfected. At their early formative stage, they are cartilaginous. The vessels of the cartilage, at this period, convey only the _lymph_, or white portion of the blood; subsequently, they convey red blood. At this time, true ossification (the deposition of phosphate and carbonate of lime) commences at certain points, which are called _the points of ossification_. 70. Most of the bones are formed of several pieces, or centres of ossification. This is seen in the long bones which have their extremities separated from the body by a thin partition of cartilage. It is some time before these separate pieces are united to form one bone. 71. When the process of ossification is completed, there is still a constant change in the bones. They increase in bulk, and become less vascular, until middle age. In advanced life, the elevations upon their surface and near the extremities become more prominent, particularly in individuals accustomed to labor. As a person advances in years, the vitality diminishes, and in extreme old age, the earthy substance predominates; consequently, the bones are extremely brittle. -=-=-=-=-=-=-=-=-=-=-=-= How can the earthy matter of the bones be shown? The animal? 69. What is the appearance of the bones in their early formative stage? When does true ossification commence? 70. How are most of the bones formed? 71. What is said of the various changes of the bones after ossification? -=-=-=-=-=-=-=-=-=-=-=-= 72. The fibrous membrane that invests the bones is called _per-i-os´te-um_; that which covers the cartilages is called _per-i-chon´dri-um_. When this membrane invests the skull, it is called _per-i-cra´ni-um_. [Illustration: Fig. 6. A section of the knee-joint. The lower part of the femur, (thigh-bone,) and upper part of the tibia, (leg-bone,) are seen ossified at 1, 1. The cartilaginous extremities of the two bones are seen at _d_, _d_. The points of ossification of the extremities, are seen at 2, 2. The patella, or knee-pan, is seen at _c_. 3, A point, or centre of ossification.] 73. The PERIOSTEUM is a firm membrane immediately investing the bones, except where they are tipped with cartilage, and the crowns of the teeth, which are protected by enamel. This membrane has minute nerves, and when healthy, possesses but little sensibility. It is the nutrient membrane of the bone, endowing its exterior with vitality; it also gives insertion to the tendons and connecting ligaments of the joints. -=-=-=-=-=-=-=-=-=-=-=-= 72. What is the membrane called that invests the bones? That covers the cartilage? That invests the skull? Explain fig. 6. 73. Describe the periosteum. -=-=-=-=-=-=-=-=-=-=-=-= 74. There are two hundred and eight[3] bones in the human body, beside the teeth. These, for convenience, are divided into four parts: 1st. The bones of the _Head_. 2d. The bones of the _Trunk_. 3d. The bones of the _Upper Extremities_. 4th. The bones of the _Lower Extremities_. [3] Some anatomists reckon more than this number, others less, for the reason that, at different periods of life, the number of pieces of which one bone is formed, varies. _Example._ The breast-bone, in infancy, has _eight_ pieces; in youth, _three_; in old age, but _one_. 75. The bones of the HEAD are divided into those of the _Skull_, _Ear_, and _Face_. 76. The SKULL is composed of eight bones. They are formed of two plates, or tablets of bony matter, united by a porous portion of bone. The external tablet is fibrous and tough; the internal plate is dense and hard, and is called the _vit´re-ous_, or glassy table. These tough, hard plates are adapted to resist the penetration of sharp instruments, while the different degrees of density possessed by the two tablets, and the intervening spongy bone, serve to diminish the vibrations that would occur in falls or blows. 77. The skull is convex externally, and at the base much thicker than at the top or sides. The most important part of the brain is placed here, completely out of the way of injury, unless of a very serious nature. The base of the cranium, or skull, has many projections, depressions, and apertures; the latter affording passages for the nerves and blood-vessels. -=-=-=-=-=-=-=-=-=-=-=-= 74. How many bones in the human body? How are they divided? 75-81. _Give the anatomy of the bones of the head._ 75. How are the bones of the head divided? 76. Describe the bones of the skull. 77. What is the form of the skull? What does the base of the skull present? -=-=-=-=-=-=-=-=-=-=-=-= 78. The bones of the cranium are united by ragged edges, called _sut´ures_. The edges of each bone interlock with each other, producing a union, styled, in carpentry, _dovetailing_. They interrupt, in a measure, the vibrations produced by external blows, and also prevent fractures from extending as far as they otherwise would, in one continued bone. From infancy to the twelfth year, the sutures are imperfect; but, from that time to thirty-five or forty, they are distinctly marked; in old age, they are nearly obliterated. [Illustration: Fig. 7. 1, 1, The coronal suture at the front and upper part of the skull, or cranium. 2, The sagittal suture on the top of the skull. 3, 3, The lambdoidal suture at the back part of the cranium.] 79. We find as great a diversity in the form and texture of the skull-bone, as in the expression of the face. The head of the New Hollander is small; that of the African is compressed; while the Caucasian is distinguished for the beautiful oval form of the head. The Greek skulls, in texture, are close and fine, while the Swiss are softer and more open. -=-=-=-=-=-=-=-=-=-=-=-= 78. How are the bones of the skull united? What are the uses of the sutures? Mention the appearance of the sutures at different ages. What does fig. 7 represent? 79. What is said respecting the form and texture of the skull in different nations? -=-=-=-=-=-=-=-=-=-=-=-= 80. In each EAR are four very small bones. They aid in hearing. 81. In the FACE are fourteen bones, some of which serve for the attachment of powerful muscles, which are more or less called into action in masticating food; others retain in place the soft parts of the face. [Illustration: Fig. 8. 1, The frontal, or bone of the forehead. 2. The parietal bone. 3, The temporal bone. 4, The zygomatic process of the temporal bone. 5, The malar (cheek) bone. 6, The superior maxillary bone, (upper jaw.) 7, The vomer, that separates the cavities of the nose. 8, The inferior maxillary bone, (lower jaw.) 9. The cavity for the eye.] 82. The TRUNK has fifty-four bones--twenty-four _Ribs_; twenty-four bones in the _Spi´nal Col´umn_, (back-bone;) four in the _Pel´vis_; the _Ster´num_, (breast-bone;) and the _Os hy-oid´es_, (the bone at the base of the tongue.) They are so arranged as to form, with the soft parts attached to them, two cavities, called the _Tho´rax_ (chest) and _Ab-do´men_. -=-=-=-=-=-=-=-=-=-=-=-= 80. How many bones in the ear? 81. How many bones in the face? What is their use? Explain fig. 8. 82-94. _Give the anatomy of the bones of the trunk._ 82. How many bones in the trunk? Name them. What do they form by their arrangement? -=-=-=-=-=-=-=-=-=-=-=-= 83. The THORAX is formed by the sternum in front; the ribs, at the sides; and the twelve dorsal bones of the spinal column, posteriorly. The natural form of the chest is a cone, with its apex above; but fashion, in many instances, has nearly inverted this order. This cavity contains the lungs, heart, and large blood-vessels. [Illustration: Fig. 9. 1, The first bone of the sternum, (breast-bone.) 2. The second bone of the sternum. 3, The cartilage of the sternum. 4, The first dorsal vertebra, (a bone of the spinal column.) 5, The last dorsal vertebra. 6, The first rib. 7, Its head. 8, Its neck. 9, Its tubercle. 10, The seventh, or last true rib. 11, The cartilage of the third rib. 12, The floating ribs.] 84. The STERNUM is composed of eight pieces in the child. These unite and form but three parts in the adult. In youth, the two upper portions are converted into bone, while the lower portion remains cartilaginous and flexible until extreme old age, when it is often converted into bone. 85. The RIBS are connected with the spinal column, and increase in length as far as the seventh. From this they successively become shorter. The direction of the ribs from above, downward, is oblique, and their curve diminishes from the first to the twelfth. The external surface of each rib is convex; the internal, concave. The inferior, or lower ribs, are, however, very flat. -=-=-=-=-=-=-=-=-=-=-=-= 83. Describe the thorax. Explain fig. 9. 84. Describe the sternum. 85. Describe the ribs. -=-=-=-=-=-=-=-=-=-=-=-= 86. The seven upper ribs are united to the sternum, through the medium of cartilages, and are called the _true ribs_. The cartilages of the next three are united with each other, and are not attached to the sternum; these are called _false ribs_. The lowest two are called _floating ribs_, as they are not connected either with the sternum or the other ribs. 87. The SPINAL COLUMN is composed of twenty-four pieces of bone. Each piece is called a _vert´e-bra_. On examining one of the bones, we find seven projections, called _processes_; four of these, that are employed in binding the bones together, are called _articulating_ processes; two of the remaining are called the _transverse_; and the other, the _spinous_. The last three give attachment to the muscles of the back. 88. The large part of the vertebra, called the body, is round and spongy in its texture, like the extremity of the round bones. The processes are of a more dense character. The projections are so arranged that a tube, or canal, is formed immediately behind the bodies of the vertebræ, in which is placed the _me-dul´la spi-na´lis_, (spinal cord,) sometimes called the pith of the back-bone. 89. Between these joints, or vertebræ, is a peculiar and highly elastic substance, which much facilitates the bending movements of the back. This compressible cushion of cartilage also serves the important purpose of diffusing and diminishing the shock in walking, running, or leaping, and tends to protect the delicate texture of the brain. -=-=-=-=-=-=-=-=-=-=-=-= 86. How are the ribs united to the sternum? 87. Describe the spinal column. 88. Give the structure of the vertebra. Where is the spinal cord placed? 89. What is placed between each vertebra? What is its use? -=-=-=-=-=-=-=-=-=-=-=-= 90. Another provision for the protection of the brain, which bears convincing proof of the wisdom and beneficence of the Creator, is the antero-posterior, or forward and backward curve of the spinal column. Were it a straight column, standing perpendicularly, the slightest jar, in walking, would cause it to recoil with a sudden jerk; because, the weight bearing equally, the spine would neither yield to the one side nor the other. But, shaped as it is, we find it yielding in the direction of the curves, and thus the force of the shock is diffused. [Illustration: Fig. 10. A vertebra of the neck. 1, The body of the vertebra. 2, The spinal canal. 4, The spinous process, cleft at its extremity. 5, The transverse process. 7, The inferior articulating process. 8, The superior articulating process.] [Illustration: Fig. 11. 1, The cartilaginous substance that connects the bodies of the vertebræ. 2, The body of the vertebra. 3, The spinous process. 4, 4, The transverse processes. 5, 5, The articulating processes. 6, 6, A portion of the bony bridge that assists in forming the spinal canal, (7.)] _Observation._ A good idea of the structure of the vertebræ may be obtained by examining the spinal column of a domestic animal, as the dog, cat, or pig. 91. The PELVIS is composed of four bones; the two _in-nom-i-na´ta_, (nameless bones,) the _sa´crum_, and the _coc´cyx_. 92. The INNOMINATUM, in the child, consists of three pieces. These, in the adult, become united, and constitute but one bone. In the sides of these bones is a deep socket, or depression, like a cup, called the _ac-e-tab´u-lum_, in which the round head of the thigh-bone is placed. -=-=-=-=-=-=-=-=-=-=-=-= 90. What is said of the curves of the spinal column? What is represented by fig. 10? By fig. 11? How can the structure of the vertebræ be seen? 91. Of how many bones is the pelvis composed? 92. What is said of the innominatum in the child? -=-=-=-=-=-=-=-=-=-=-=-= 93. The SACRUM, so called because the ancients offered it in sacrifices, is a wedge-shaped bone, that is placed between the innominata, and to which it is bound by ligaments. Upon its upper surface it connects with the lower vertebra. At its inferior, or lower angle, it is united to the coccyx. It is concave upon its anterior, and convex upon its posterior surface. [Illustration: Fig. 12. 1, 1, The innominata, (nameless bones.) 2, The sacrum. 3, The coccyx. 4, 4, The acetabulum. a, a, The pubic portion of the innominata. d, The arch of the pubes; e, The junction of the sacrum and lower lumbar vertebra.] 94. The COCCYX, in infants, consists of several pieces, which, in youth, become united and form one bone. This is the terminal extremity of the spinal column. -=-=-=-=-=-=-=-=-=-=-=-= In the adult? Describe the acetabulum. 93. Describe the sacrum. Explain fig. 12. 94. Describe the coccyx. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER V. ANATOMY OF THE BONES, CONTINUED 95. The bones of the upper and lower limbs are enlarged at each extremity, and have projections, or processes. To these, the tendons of muscles and ligaments are attached, which connect one bone with another. The shaft of these bones is cylindrical and hollow, and in structure, their exterior surface is hard and compact, while the interior portion is of a reticulated character. The enlarged extremities of the round bones are more porous than the main shaft. 96. The UPPER EXTREMITIES contain sixty-four bones--the _Scap´u-la_, (shoulder-blade;) the _Clav´i-cle_, (collar-bone;) the _Hu´mer-us_, (first bone of the arm;) the _Ul´na_ and _Ra´di-us_, (bones of the fore-arm;) the _Car´pus_, (wrist;) the _Met-a-car´pus_, (palm of the hand;) and the _Pha-lan´ges_, (fingers and thumb.) 97. The CLAVICLE is attached, at one extremity, to the sternum; at the other, it is united to the scapula. It is shaped like the Italic _[s]_. Its use is to keep the arms from sliding toward the breast. 98. The SCAPULA is situated upon the upper and back part of the chest. It is flat, thin, and of a triangular form. This bone lies upon and is retained in its position by muscles. By their contractions it may be moved in different directions. 99. The HUMERUS is cylindrical, and is joined at the elbow with the ulna of the fore-arm; at the scapular extremity, it is lodged in the _glenoid_ cavity, where it is surrounded by a membranous bag, called the _capsular ligament_. -=-=-=-=-=-=-=-=-=-=-=-= 95-104. _Give the anatomy of the bones of the upper extremities._ 95. Give the structure of the bones of the extremities. 96. How many bones in the upper extremities? Name them. 97. Give the attachments of the clavicle. What is its use? 98. Describe the scapula. How is it retained in its position? 99. Describe the humerus. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 13. 1, The shaft of the humerus. 2, The large, round head that is placed in the glenoid cavity. 3, 4, Processes, to which muscles are attached. 5, A process, called the external elbow. 6, A process, called the internal elbow. 7, The articulating surface upon which the ulna rolls.] [Illustration: Fig. 14. 1, The body of the ulna. 2, The shaft of the radius. 3, The upper articulation of the radius and ulna. 4, Articulating cavity, in which the lower extremity of the humerus is placed. 5, Upper extremity of the ulna, called the olecranon process, which forms the point of the elbow. 6, Space between the radius and ulna, filled by the intervening ligament. 7, Styloid process of the ulna. 8, Surface of the radius and the ulna, where they articulate with the bones of the wrist. 9, Styloid process of the radius.] 100. The ULNA articulates with the humerus at the elbow, and forms a perfect hinge-joint. This bone is situated on the inner side of the fore-arm. -=-=-=-=-=-=-=-=-=-=-=-= What is represented by fig. 13? By fig. 14? 100. Describe the ulna. -=-=-=-=-=-=-=-=-=-=-=-= 101. The RADIUS articulates with the bones of the carpus and forms the wrist-joint. This bone is situated on the outside of the fore-arm, (the side on which the thumb is placed.) The ulna and radius, at their extremities, articulate with each other, by which union the hand is made to rotate, permitting its complicated and varied movements. 102. The CARPUS is composed of eight bones, ranged in two rows, and so firmly bound together, as to permit only a small amount of movement. [Illustration: Fig. 15. U, The ulna. R, The radius. S, The scaphoid bone. L, The semilunar bone. C, The cuneiform bone. P, The pisiform bone. These four form the first row of carpal bones. T, T, The trapezium and trapezoid bones. M, The os magnum. U, The unciform bone. These four form the second row of carpal bones. 1, 1, 1, 1, 1, The metacarpal bones of the thumb and fingers.] [Illustration: Fig. 16. 10, 10, 10, The metacarpal bones of the hand. 11, 11, First range of finger-bones. 12, 12, Second range of finger-bones. 13, 13, Third range of finger-bones. 14, 15, Bones of the thumb.] 103. The METACARPUS is composed of five bones, upon four of which the first range of the finger-bones is placed; and upon the other, the first bone of the thumb. The five metacarpal bones articulate with the second range of carpal bones. -=-=-=-=-=-=-=-=-=-=-=-= 101. The radius. 102. How many bones in the carpus? How are they ranged? 103. Describe the metacarpus. -=-=-=-=-=-=-=-=-=-=-=-= 104. The PHALANGES of the fingers have three ranges of bones, while the thumb has but two. _Observation._ The wonderful adaptation of the hand to all the mechanical offices of life, is one cause of man's superiority over the rest of creation. This arises from the size and strength of the thumbs, and the different lengths of the fingers. 105. The LOWER EXTREMITIES contain sixty bones--the _Fe´mur_, (thigh-bone;) the _Pa-tel´la_, (knee-pan;) the _Tib´i-a_, (shin-bone;) the _Fib´u-la_, (small bone of the leg;) the _Tar´sus_, (instep;) the _Met-a-tar´sus_, (middle of the foot;) and the _Pha-lan´ges_, (toes.) 106. The FEMUR is the longest bone in the system. It supports the weight of the head, trunk, and upper extremities. The large, round head of this bone is placed in the acetabulum. This articulation is a perfect specimen of the ball and socket joint. 107. The PATELLA is a small bone connected with the tibia by a strong ligament. The tendon of the _ex-tens´or_ muscles of the leg is attached to its upper edge. This bone is placed on the anterior part of the lower extremity of the femur, and acts like a pulley, in the extension of the limb. 108. The TIBIA is the largest bone of the leg. It is of a triangular shape, and enlarged at each extremity. 109. The FIBULA is a smaller bone than the tibia, but of similar shape. It is firmly bound to the tibia, at each extremity. 110. The TARSUS is formed of seven irregular bones, which are so firmly bound together as to permit but little movement. -=-=-=-=-=-=-=-=-=-=-=-= 104. How many ranges of bones have the phalanges? 105-112. _Give the anatomy of the bones of the lower extremities._ 105. How many bones in the lower extremities? Name them. 106. Describe the femur. 107. Describe the patella. What is its function? 108. What is the largest bone of the leg called? What is its form? 109. What is said of the fibula? 110. Describe the tarsus. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 17. 1, The shaft of the femur, (thigh-bone.) 2, A projection, called the trochantar minor, to which are attached some strong muscles. 4, The trochantar major, to which the large muscles of the hip are attached. 3, The head of the femur. 5, The external projection of the femur, called the external condyle. 6, The internal projection, called the internal condyle. 7, The surface of the lower extremity of the femur, that articulates with the tibia, and upon which the patella slides.] [Illustration: Fig. 18. 1, The tibia. 5, The fibula. 8, The space between the two, filled with the inter-osseous ligament. 6, The junction of the tibia and fibula at their upper extremity. 2, The external malleolar process, called the external ankle. 3, The internal malleolar process, called the internal ankle. 4, The surface of the lower extremity of the tibia, that unites with one of the tarsal bones to form the ankle-joint. 7, The upper extremity of the tibia, upon which the lower extremity of the femur rests.] -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 17. Explain fig. 18. -=-=-=-=-=-=-=-=-=-=-=-= 111. The METATARSAL bones are five in number. They articulate at one extremity with one range of tarsal bones; at the other extremity, with the first range of the toe-bones. [Illustration: Fig. 19. A representation of the upper surface of the bones of the foot. 1, The surface of the astragulus, where it unites with the tibia. 2, The body of the astragulus. 3, The calcis, (heel-bone.) 4, The scaphoid bone. 5, 6, 7, The cuneiform bones. 8, The cuboid. 9, 9, 9, The metatarsal bones. 10, The first bone of the great toe. 11, The second bone. 12, 13, 14, Three ranges of bones, forming the small toes] [Illustration: Fig. 20. A side view of the bones of the foot, showing its arched form. The arch rests upon the _heel_ behind, and the _ball_ of the toes in front. 1, The lower part of the tibia. 2, 3, 4, 5, Bones of the tarsus. 6, The metatarsal bone. 7, 8, The bones of the great toe. These bones are so united as to secure a great degree of elasticity, or spring.] _Observation._ The tarsal and metatarsal bones are united so as to give the foot an arched form, convex above, and concave below. This structure conduces to the elasticity of the step, and the weight of the body is transmitted to the ground by the spring of the arch, in a manner which prevents injury to the numerous organs. -=-=-=-=-=-=-=-=-=-=-=-= 111. Describe the metatarsal bones. Explain fig. 19. What is represented by fig. 20? What is said of the arrangement of the bones of the foot? -=-=-=-=-=-=-=-=-=-=-=-= 112. The PHALANGES (fig. 19) are composed of fourteen bones; each of the small toes has three ranges of bones, while the great toe has but two. 113. The JOINTS form an interesting part of the body. In their construction, every thing shows the regard that has been paid to the security and the facility of motion of the parts thus connected together. They are composed of the extremities of two or more bones, _Car´ti-lages_, (gristles,) _Syn-o´vi-al_ membrane, and _Lig´a-ments_. [Illustration: Fig. 21 The relative position of the bones, cartilages, and synovial membrane. 1, 1, The extremities of two bones that concur to form a joint. 2, 2, The cartilages that cover the end of the bones. 3, 3, 3, 3, The synovial membrane which covers the cartilage of both bones, and is then doubled back from one to the other; it is represented by the dotted lines.] [Illustration: Fig. 22. A vertical section of the knee-joint. 1, The femur. 3, The patella. 5, The tibia. 2, 4, The ligaments of the patella. 6, The cartilage of the tibia 12, The cartilage of the femur. * * * *, The synovial membrane.] 114. CARTILAGE is a smooth, solid, elastic substance, of a pearly whiteness, softer than bone. It forms upon the articular surfaces of the bones a thin incrustation, not more than the sixteenth of an inch in thickness. Upon convex surfaces it is the thickest in the centre, and thin toward the circumference; while upon concave surfaces, an opposite arrangement is presented. -=-=-=-=-=-=-=-=-=-=-=-= 112. Describe the phalanges. 113-118. _Give the anatomy of the joints._ 113. What is said of the joints? Of what are the joints composed? What is illustrated by fig. 21? By fig. 22? 114. Define cartilage. -=-=-=-=-=-=-=-=-=-=-=-= 115. The SYNOVIAL MEMBRANE is a thin, membranous layer, which covers the cartilages, and is thence bent back, or reflected upon the inner surfaces of the ligaments which surround and enter into the composition of the joints. This membrane forms a closed sac, like the membrane that lines an egg-shell. [Illustration: Fig. 23. The anterior ligaments of the knee-joint. 1, The tendon of the muscle that extends the leg. 2, The patella. 3, The anterior ligament of the patella, near its insertion. 4, 4, The synovial membrane. 5, The internal lateral ligament. 6, The long external lateral ligament. 7, The anterior and superior ligament that unites the fibula to the tibia.] [Illustration: Fig. 24. 2, 3, The ligaments that extend from the clavicle (1) to the scapula (4.) The ligaments 5, 6, extend from the scapula to the first bone of the arm.] 116. Beside the synovial membrane, there are numerous smaller sacs, called _bur´sæ mu-co´sæ_. These are often associated with the articulation. In structure, they are analogous to synovial membranes, and secrete a similar fluid. -=-=-=-=-=-=-=-=-=-=-=-= 115. Describe the synovial membrane. 116. Describe the bursæ mucosæ. What is represented by fig. 23? By fig. 24? -=-=-=-=-=-=-=-=-=-=-=-= 117. The LIGAMENTS are composed of numerous straight fibres, collected together, and arranged into short bands of various breadths, or so interwoven as to form a broad layer, which completely surrounds the articular extremities of the bones, and constitutes a capsular ligament. These connecting bands are white, glistening, and inelastic. Most of the ligaments are found exterior to the synovial membrane. 118. The bones, cartilages, ligaments, and synovial membrane are insensible when in health; yet they are supplied with organic nerves, as well as with arteries, veins, and lymphatics. _Observation._ The joints of the domestic animals are similar in their construction to those of man. To illustrate this part of the body, a fresh joint of the calf or sheep may be used. After divesting the joints of the skin, the satin-like bands, or ligaments, will be seen passing from one bone to the other, under which may be observed the membranous bag, called the capsular ligament. This is very smooth, as it is lined with the soft synovial membrane, beneath which will be seen the cartilage, that may be cut with a knife, and under this the rough extremity of the ends of the bones. -=-=-=-=-=-=-=-=-=-=-=-= 117. Of what are ligaments composed? What is the appearance of these bands? Where are they found? 118. With what vessels are the cartilages and ligaments supplied? How can the structure of the joints be explained? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER VI. PHYSIOLOGY OF THE BONES. 119. The bones are the framework of the system. By their solidity and form, they not only retain every part of the fabric in its proper shape, but afford a firm surface for the attachment of the muscles and ligaments. By means of the bones, the human frame presents to the eye a wonderful piece of mechanism, uniting the most finished symmetry of form with freedom of motion, and also giving security to many important organs. 120. To give a clear idea of the relative uses of the bones and muscles, we will quote the comparison of another, though, as in other comparisons, there are points of difference. The "bones are to the body what the masts and spars are to the ship,--they give support and the power of resistance. The muscles are to the bones what the ropes are to the masts and spars. The bones are the levers of the system; by the action of the muscles their relative positions are changed. As the masts and spars of a vessel must be sufficiently firm to sustain the action of the ropes, so the bones must possess the same quality to sustain the action of the muscles in the human body." 121. Some of the bones are designed exclusively for the protection of the organs which they enclose. Of this number are those that form the skull, the sockets of the eye, and the cavity of the nose. Others, in addition to the protection they give to important organs, are useful in movements of certain kinds. Of this class are the bones of the spinal column, and ribs. Others are subservient to motion. Of this class are the upper and lower extremities. -=-=-=-=-=-=-=-=-=-=-=-= 119-128. _Give the physiology of the bones._ 119. How may the bones be considered? 120. To what may the bones be compared? 121. Give the different offices of the bones. -=-=-=-=-=-=-=-=-=-=-=-= 122. The bones are subject to growth and decay; to removal of old, useless matter, and the deposit of new particles, as in other tissues. This has been tested by the following experiment. Some of the inferior animals were fed with food that contained madder. In a few days, some of the animals were killed, and their bones exhibited an unusually reddish appearance. The remainder of the animals were, for a few weeks, fed on food that contained no coloring principle. When they were killed, their bones exhibited the usual color of such animals. The coloring matter, which had been deposited, had been removed by the action of the lymphatics. 123. The extremities of the bones that concur in forming a joint, correspond by having their respective configurations reciprocal. They are, in general, the one convex, and the other concave. In texture they are porous, and consequently more elastic than if more compact. These are covered with a cushion of cartilage. The elastic character of these parts acts as so many springs, in diminishing the jar which important organs of the system would otherwise receive. 124. The synovial membrane secretes a viscous fluid, which is called _syn-o´vi-a_. This lubricating fluid of the joints enables the surfaces of the bones and tendons to move smoothly upon each other, thus diminishing the friction consequent on their action. _Observations._ 1st. In this secretion is manifested the skill and omnipotence of the Great Architect; for no machine of human invention supplies to itself, by its own operations, the necessary lubricating fluid. But, in the animal frame, it is supplied in proper quantities, and applied in the proper place, and at the proper time. -=-=-=-=-=-=-=-=-=-=-=-= 122. What is said of the change in bones? How was it proved that there was a constant change in the osseous fabric? 123. What is said of the extremities of the bones that form a joint? 124. What is synovia? Its use? What is said of this lubricating fluid? -=-=-=-=-=-=-=-=-=-=-=-= 2d. In some cases of injury and disease, the synovial fluid is secreted in large quantities, and distends the sac of the joint. This affection is called dropsy of the joint, and occurs most frequently in that of the knee. 125. The function of the ligaments is to connect and bind together the bones of the system. By them the small bones of the wrist and foot, as well as the large bones, are as securely fastened as if retained by clasps of steel. Some of them are situated within the joints, like a central cord, or pivot, (3, fig. 26.) Some surround it like a hood, and contain the lubricating synovial fluid, (8, 9, fig. 25,) and some in the form of bands at the side, (5, 6, fig. 23.) [Illustration: Fig. 25. 8, 9, The ligaments that extend from the hip-bone (6) to the femur, (5.)] [Illustration: Fig. 26. 2, The socket of the hip-joint. 5, The head of the femur, which is lodged in the socket. 3, The ligament within the socket.] 126. By the ligaments the lower jaw is bound to the temporal bones, and the head to the neck. They extend the whole length of the spinal column, in powerful bands, on the outer surface, between the spinal bones, and from one spinous process to another. They bind the ribs to the vertebræ, to the transverse process behind, and to the sternum in front; and this to the clavicle; and this to the first rib and scapula; and this last to the humerus. -=-=-=-=-=-=-=-=-=-=-=-= What is the effect when the synovial fluid is secreted in large quantities? 125. What is the function of the ligaments? 126. Mention how the bones of the system are connected. -=-=-=-=-=-=-=-=-=-=-=-= 127. They also bind the two bones of the fore-arm at the elbow-joint; and these to the wrist; and these to each other and to those of the hand; and these last to each other and to those of the fingers and thumb. In the same manner, they bind the bones of the pelvis together; and these to the femur; and this to the two bones of the leg and patella; and so on, to the ankle, foot, and toes, as in the upper extremities. [Illustration: Fig. 27. 1, A front view of the lateral ligaments of the finger-joints. 2, A view of the anterior ligaments (_a_, _b_,) of the finger-joints. 3, A side view of the lateral ligaments of the finger joints.] 128. The different joints vary in range of movement, and in complexity of structure. Some permit motions in all directions, as the shoulder; some move in two directions, permitting only flexion and extension of the part, as the elbow; while others have no movement, as the bones of the head in the adult. -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 27. 128. Describe the variety of movements in the different joints. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 28. 1, 1, The spinal column. 2, The skull. 3, The lower jaw. 4, The sternum. 5, The ribs. 6, 6, The cartilages of the ribs. 7, The clavicle. 8, The humerus. 9, The shoulder-joint. 10, The radius. 11, The ulna. 12, The elbow joint. 13, The wrist. 14, The hand. 15, The haunch-bone. 16, The sacrum. 17, The hip-joint. 18, The thigh-bone. 19, The patella. 20, The knee-joint. 21, The fibula. 22, The tibia. 23, The ankle-joint. 24, The foot. 25, 26, The ligaments of the clavicle, sternum, and ribs. 27, 28, 29, The ligaments of the shoulder, elbow, and wrist. 30, The large artery of the arm. 31, The ligaments of the hip-joint. 32, The large blood-vessels of the thigh. 33, The artery of the leg. 34, 35, 36, The ligaments of the patella, knee, and ankle.] _Note._ Let the pupil, in form of topics, review the anatomy and physiology of the bones from fig. 28, or from anatomical outline plates No. 1 and 2. CHAPTER VII HYGIENE OF THE BONES. 129. _The bones increase in size and strength by use, while they are weakened by inaction._ Exercise favors the deposition of both animal and earthy matter, by increasing the circulation and nutrition in this texture. For this reason, the bones of the laborer are dense and strong, while those who neglect exercise, or are unaccustomed to manual employment, are deficient in size, and have not a due proportion of earthy matter to give them the solidity and strength of the laboring man. _Observation._ The tendons of the muscles are attached near the extremities of the bones. Exercise of the muscles increases the action of the vessels of that part to which the tendons are attached, and thus increases the nutrition and size of this portion of the bone. Hence the joints of an industrious mechanic or farmer are larger than those of an individual who has not pursued manual vocations. 130. _The gelatinous bones of the child are not so well adapted for labor and severe exercise as those of an adult._ 1st. They are liable to become distorted. 2d. They are consolidated by the deposition of earthy material before they are fully and properly developed. If a young animal, as the colt, be put to severe, continued labor, the deposition of earthy matter is hastened, and the bones are consolidated before they attain full growth. Such colts make small and inferior animals. Similar results follow, if a youth is compelled to toil unduly before maturity of growth is attained. On the other hand, moderate and regular labor favors a healthy development and consolidation of the bones. -=-=-=-=-=-=-=-=-=-=-=-= 129-148. _Give the hygiene of the bones._ 129. What effect has exercise upon the bones? What effect has inaction? Why are the joints of the industrious farmer and mechanic larger than those of a person unaccustomed to manual employment? 130. Give the first reason why the bones of the child are not adapted to severe exercise. The second reason. -=-=-=-=-=-=-=-=-=-=-=-= 131. _The kind and amount of labor should be adapted to the age, health, and development of the bones._ Neither the flexible bones of the child nor the brittle bones of the aged man are adapted, by their organization, to long-continued, and hard labor. Those of the one bend too easily, while those of the other fracture too readily. In middle age, the proportions of animal and earthy matter are, usually, such as to give the proper degree of flexibility, firmness, and strength for labor, with little liability to injury. 132. _The imperfectly developed bones of the young child will not bear long-continued exertions or positions without injury._ Hence the requisitions of the rigid disciplinarian of schools, are unwise when he compels his pupils to remain in one position for a long time. He may have a "quiet school;" but, not unfrequently, by such discipline, the constitution is impaired, and permanent injury is done to the pupils. 133. _The lower extremities, in early life, contain but a small proportion of earthy matter_; they bend when the weight of the body is thrown upon them for a long time. Hence, the assiduous attempts to induce children to stand or walk, either naturally or artificially, when very young, are ill advised, and often productive of serious and permanent evil. The "bandy" or bow legs are thus produced. -=-=-=-=-=-=-=-=-=-=-=-= What effect has moderate, regular labor upon the growing youth? 131. What remark respecting the kind and amount of labor? At what age are the bones best fitted for labor? 132. What effect has long-continued exertions or positions on the bones of a child? What is said of the requisitions of some teachers, who have the famed "quiet schools"? 133. Why should not the child be induced to stand or walk, either naturally or artificially, at too early an age? -=-=-=-=-=-=-=-=-=-=-=-= 134. _The benches or chairs for children in a school-room should be of such a height as to permit the feet to rest on the floor._ If the bench is so high as not to permit the feet to rest upon the floor, the weight of the limbs below the knee may cause the flexible bone of the thigh to become curved. The child thus seated, is inclined to lean forward, contracting an injurious and ungraceful habit. Again, when the feet are not supported, the child soon becomes exhausted, restless, and unfit for study. In the construction of a school-room, the benches should be of different heights, so as to be adapted to the different pupils, and they should also have appropriate backs. [Illustration: Fig. 29. The position assumed when the seat is of proper height, and the feet supported.] [Illustration: Fig. 30. The position a child naturally assumes when the seat is so high that the feet are not supported.] -=-=-=-=-=-=-=-=-=-=-=-= 134. What is said of the benches or chairs in a school-room? What is represented by fig. 29? By fig. 30? What is the effect when the lower limbs are not supported? -=-=-=-=-=-=-=-=-=-=-=-= 135. _Compression of the chest should be avoided._ In children, and also in adults, the ribs are very flexible, and a small amount of pressure will increase their curvature, particularly at the lower part of the chest, and thus lessen the size of this cavity. The lower ribs are united to the breast-bone, by long, yielding cartilages, and compression may not only contract the chest, but an unseemly and painful ridge may be produced, by the bending of the cartilages, on one or both sides of the sternum. [Illustration: Fig. 31. A natural and well-proportioned chest.] [Illustration: Fig. 32. A chest fashionably deformed.] -=-=-=-=-=-=-=-=-=-=-=-= 135. Why should compression of the chest be avoided? What is represented by fig. 31? By fig. 32? -=-=-=-=-=-=-=-=-=-=-=-= 136. Again, the cartilages on one side may be bent outward, while those on the opposite side are bent inward, thus forming a depression parallel with the sternum. In some instances, the anterior extremity of the lower ribs on each side are brought nearly or quite together. In these instances, the movable extremities of the ribs are drawn down toward the haunch-bones, while the space between the ribs is lessened. All this may be effected by tight or "snug" clothing. Therefore the apparel of a child should be loose, and supported over the shoulders, to avoid the before-mentioned evils. The same may be said of the clothing for adults. 137. _The erect position in sitting and standing should be assiduously observed._ The spinal column, in its natural position, curves from front to back, but not from side to side The admirable arrangement of the bones, alternating with cartilages, permits a great variety of motions and positions; and when the spine is inclined to either side, the elasticity of its cartilages tends to restore it to its natural position. For this reason we may incline the spinal column in any direction for a short time, without danger of permanent curvature, if, afterward, the erect position is assumed.[4] [4] Compare 1, 1, Fig. 28, with 2, 2, 2, Fig. 48. 138. But if a stooping position, or a lateral curved posture, is continued for a long time, the spinal column does not easily recover its proper position, for the compressed edges of the cartilages lose their power of reaction, and finally one side of the cartilage becomes thinned, while the other is thickened; and these wedge-shaped cartilages produce a permanent curvature of the spinal column. In a similar way, the student, seamstress, artisan, and mechanic acquire a stooping position, and become round shouldered, by inclining forward to bring their books or work nearer the eyes. -=-=-=-=-=-=-=-=-=-=-=-= 136. May simply "snug" clothing compress the cartilages? How should the apparel of a child be worn? 137. In what direction does the spinal column, in its natural position, curve? What restores it to its natural position when curved laterally? 138. What is the effect if a lateral curved position of the spinal column is continued for a long time? 139. When one shoulder is elevated for a long time, what is the effect upon the spinal column? -=-=-=-=-=-=-=-=-=-=-=-= 139. Pupils, while writing, drawing, and sometimes while studying, frequently incline the spinal column to one side, in order to accommodate themselves to the desks at which they are seated. Often, these are higher than the elbow as it hangs from the shoulder while at rest. This attitude elevates one shoulder while it depresses the other; consequently, the upper part of the spinal column is inclined toward the elevated shoulder, and the lower part is curved in the opposite direction, giving the form of the letter _S_ to the supporting column of the body. [Illustration: Fig. 33. The table is of proper height, the position is correct, and the spinal column, 1, 1, is straight, while the shoulders are of equal height.] -=-=-=-=-=-=-=-=-=-=-=-= What does fig. 33 represent? -=-=-=-=-=-=-=-=-=-=-=-= _Experiment._ Let a pupil be placed at a desk or table with one elbow raised, as is frequently seen while writing, or at study, and observe the condition of the shoulder and spinal column in this position. Place another pupil at a table no higher than the elbow when it hangs by the side while sitting, and observe the appearance of the shoulders and spinal column. By a comparison of the two attitudes, the preceding remarks will be comprehended and appreciated. [Illustration: Fig. 34. The table is too high, and the position is oblique and improper. The right shoulder is seen higher than the left, while the spinal column, 1, 1, exhibits three curves.] 140. One shoulder may be elevated, and no injurious results follow, provided care is taken not to keep it in the raised position too long, or if the opposite shoulder is elevated for the same period of time. The right shoulder projects more frequently than the left. This arises from the greater use of the right hand with the shoulder elevated, and not unfrequently the oblique positions assumed in performing the daily vocations of life. With proper care, and by calling into action the left shoulder, this deformity can be prevented. -=-=-=-=-=-=-=-=-=-=-=-= What experiment is mentioned? What does fig. 34 represent? 140. How can one shoulder be elevated and no injurious results follow? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 35. A representation of a deformed trunk.] 141. The loss of symmetry and diminution of height from deformed spines are minor considerations, compared with the distortions that the chest experiences, thereby impairing respiration and inducing diseases of the heart and lungs. The invasion of the functions of these two important organs lessens the vitality of the whole system, and causes general ill health. Again, the curvature of the spinal column is frequently attended by irritation and disease of the spinal cord. -=-=-=-=-=-=-=-=-=-=-=-= Why does the right shoulder project more frequently than the left? How can this deformity be prevented? 141. What is said of deformed spinal columns? -=-=-=-=-=-=-=-=-=-=-=-= 142. Eminent physicians, both in this country and France state that not more than one female in ten, who has been fashionably educated, is free from deformities of the shoulder or spinal column. Teachers, as well as mothers, should notice the positions of the child in performing the tasks allotted to it, whether studying or pursuing any employment. The feebler the organization of the child, the more frequently should there be a change of position. 143. When a slight projection of the shoulder, with a curvature of the spine, exists, it can be improved by walking with a book, or something heavier, upon the head; to balance which, the spinal column must be nearly erect. Those people that carry burdens upon their heads seldom have crooked spines. _Observation._ Persons from the North, in travelling through the Southern States, are surprised to see the heavy burdens that the porters carry on their heads. It is not unusual to see them walking at a rapid pace, with one or two trunks, weighing fifty or eighty pounds each, upon their heads. Occasionally, we meet an itinerant toy-man, with his tray of fragile merchandise upon his head, walking with as much apparent security, as though his toys, or images, were in his hands. This is the easiest method of carrying burdens, because the position of the head and spinal column is erect. 144. _If the animal and earthy matter of the bones is not deposited in proper proportions, they are deficient in strength._ If the gelatin predominates, the bones are weak, and become distorted. When nutrition is defective in the cylindrical bones, the heads are generally enlarged, and the shafts crooked; if in the spinal column, it may be curved; or in the cranium, it may be enlarged. This disease is familiarly known by the name of rickets. It is most common among these who have poor and insufficient food, live in dark, damp rooms, and breathe a vitiated air. The prevention and remedies for this disease are cleanliness, regular exercise, pure air, and nutritious food. -=-=-=-=-=-=-=-=-=-=-=-= 142. What statement by eminent physicians respecting deformities of the spine? What caution to teachers and mothers? 143. Why should we stand and sit erect? How may slight deformities of the spine be prevented? What is frequently noticed in travelling South? 144. What is the effect upon the bones when the gelatin preponderates? -=-=-=-=-=-=-=-=-=-=-=-= 145. When a bone is broken, some days elapse before the substance that reunites it is thrown out from the blood. In young persons, it may be secreted during the second or third week, and in individuals advanced in life, usually during the third and fourth week. When the bone is uniting, during the second, third, or fourth week, the attention of a surgeon is more needed than during the first week. At this time, the ends of the bone should be placed together with accuracy, which requires the careful application of proper dressing. After the bones have united, it will take some weeks to consolidate the uniting material and render the "callus," or union, firm. During this time, the limb should be used with care. _Observation._ When a bone is fractured, a surgeon is immediately called, and the bone is "set." While the limb remains swelled and painful, the surgeon is required to attend and keep the dressings (bandages and splints) on. When the swelling has abated, and the pain subsided, frequently the patient intimates to the surgeon that his services can be dispensed with, as the "limb is doing well." This is the most important period, as the bone is uniting, and, unless the ends are nicely adjusted, the dressing properly applied, the person will find, on recovery, a shortened and crooked limb. The surgeon is then censured, when he is not blamable. -=-=-=-=-=-=-=-=-=-=-=-= What is one cause of rickets? What are the prevention and remedies for this disease? 145. Does the time vary when the reuniting substance of the bone is secreted from the blood? When is the surgeon's care most needed? Why? -=-=-=-=-=-=-=-=-=-=-=-= 146. It is seldom that a bone is displaced without injury to the connecting ligaments and membranes. When these connecting bands are lacerated, pain, swelling, and other symptoms indicating inflammation succeed, which should be removed by proper treatment, directed by a surgical adviser. 147. In sprains, but few, if any, of the fibres of the connecting ligaments are lacerated; but they are unduly strained and twisted, which occasions acute pain at the time of the injury. This is followed by inflammation and weakness of the joints. The treatment of these injuries is similar to that of a dislocated bone after its reduction. The most important item in the treatment during the few first days, is rest. 148. In persons of scrofulous constitutions, and those in whom the system is enfeebled by disease, white swellings and other chronic diseases of the joints frequently succeed sprains. Such persons cannot be too assiduous in adopting a proper and early treatment of injured joints. -=-=-=-=-=-=-=-=-=-=-=-= 146. What parts are injured in the displacement of a bone? 147. What causes the acute pain in sprains? What is a good remedy for this kind of injury? 148. What caution to persons of scrofulous constitutions? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER VIII THE MUSCLES. 149. All the great motions of the body are caused by the movement of some of the bones which form the framework of the system; but these, independently of themselves, have not the power of motion, and only change their position through the action of other organs attached to them, which, by contracting, draw the bones after them. In some of the slight movements, as the winking of the eye, no bones are displaced. These moving, contracting organs are the _Mus´cles_, (lean meat.) ANATOMY OF THE MUSCLES. 150. The MUSCLES, by their size and number, constitute the great bulk of the body, upon which they bestow form and symmetry. In the limbs, they are situated around the bones, which they invest and defend, while they form, to some of the joints, their principal protection. In the trunk, they are spread out to enclose cavities, and constitute a defensive wall, capable of yielding to internal pressure, and reassuming its original state. 151. In structure, a muscle is composed of _fas-cic´u-li_ (bundles of fibres) of variable size. These are enclosed in a cellular membranous investment, or sheath. Every bundle composed of a number of small fibres, and each fibre consists of a number of filaments, each of which is enclosed in a delicate sheath. Toward the extremity of the organ the muscular fibre ceases, and the cellular structure becomes aggregated, and so modified as to constitute _ten´dons_, (cords,) by which the muscle is tied to the surface of the bone. The union is so firm, that, under extreme violence, the bone will sooner break than permit the tendon to separate from its attachment. In some situations, there is an expansion of the tendon, in the manner of a membrane, called _Ap-o-neu-ro´sis_, or _Fas´ci-a_. -=-=-=-=-=-=-=-=-=-=-=-= 149. How are all the motions of the body produced? What are these motor organs called? 150-160. _Give the anatomy of the muscles._ 150. What is said of the muscles? 151. Give their structure. -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ The pupil can examine a piece of boiled beef, or the leg of a fowl, and see the structure of the fibres and tendons of a muscle. [Illustration: Fig. 36. 1, A representation of the direction and arrangement of the fibres in a fusiform, or spindle-shaped muscle. 2, In a radiated muscle. 3, In a penniform muscle. 4, In a bipenniform muscle. _t_, _t_, The tendons of a muscle.] 152. Muscles present various modifications in the arrangement of their fibres, as relates to their tendinous structure. Sometimes they are completely longitudinal, and terminate, at each extremity, in a tendon, the entire muscle being spindle-shaped. In other situations, they are disposed like the rays of a fan, converging to a tendinous point, and constituting a _ra´di-ate_ muscle. Again they are _pen´ni-form_, converging, like the plumes of a pen, to one side of a tendon, which runs the whole length of the muscle; or they are _bi-pen´ni-form_, converging to both sides of the tendon. -=-=-=-=-=-=-=-=-=-=-=-= How are tendons or cords formed? What is the expansion of a tendon called? How can the structure of muscles and their fibres be shown? What does fig. 36 represent? 152. Give the different arrangements of muscular fibres. -=-=-=-=-=-=-=-=-=-=-=-= 153. In the description of a muscle, its attachments are expressed by the terms "origin" and "insertion." The term _origin_ is generally applied to the more fixed or central attachment, or to the point toward which motion is directed; while _insertion_ is assigned to the more movable point, or to that most distant from the centre. The middle, fleshy portion is called the "belly," or "swell." The color of a muscle is red in warm-blooded fish and animals; and each fibre is supplied with arteries, veins, lymphatics, and both sensitive and motor nervous filaments. 154. The FASCIA is of various extent and thickness, distributed through the different regions of the body, for the purpose of investing and protecting the softer and more delicate organs. An instance is seen in the membrane which envelopes a leg of beef, and which is observed on the edges of the slices when it is cut for broiling. When freshly exposed, it is brilliant in appearance, tough, and inelastic. In the limbs it forms distinct sheaths to all the muscles. 155. This tendinous membrane assists the muscles in their action, by keeping up a tonic pressure on their surface. It aids materially in the circulation of the fluids, in opposition to the laws of gravity. In the palm of the hand and sole of the foot, it is a powerful protection to the structures that enter into the formation of these parts. In all parts of the system, the separate muscles are not only invested by fascia, but they are arranged in layers, one over another. The sheath of each muscle is loosely connected with another, by the cellular membrane. -=-=-=-=-=-=-=-=-=-=-=-= 153. What is meant by the origin of a muscle? The insertion? The swell? What is the color of muscles? With what is each muscular fibre supplied? 154. What is said of fascia? What is its appearance when freshly exposed? 155. What effect has it on the muscles? Give other uses of the fascia. -=-=-=-=-=-=-=-=-=-=-=-= 156. The interstices between the different muscles are filled with adipose matter, or fat. This is sometimes called the packing of the system. To the presence of this tissue, youth are indebted for the roundness and beauty of their limbs. [Illustration: Fig. 37. A transverse section of the neck. The separate muscles, as they are arranged in layers, with their investing fasciæ, are beautifully represented. As the system is symmetrical, figures are placed only on one side. In the trunk the muscles are arranged in layers, surrounded by fasciæ, as in the neck. The same is true of the muscles of the upper and lower limbs. 12, The trachea, (windpipe.) 13, The oesophagus, (gullet.) 14, The carotid artery and jugular vein. 28, One of the bones of the spinal column. The figures that are placed in the white spaces represent some of the fasciæ; the other figures indicate muscles.] 157. The muscles may be arranged, in conformity with the general division of the body, into four parts: 1st. Those of the _Head_ and _Neck_. 2d. Those of the _Trunk_. 3d. Those of the _Upper Extremities_. 4th. Those of the _Lower Extremities_. -=-=-=-=-=-=-=-=-=-=-=-= 156. Give a reason why the limbs of youth are rounder than those of the aged. Describe fig. 37. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 38. The superficial layer of muscles on the face and neck. 1, 1, The occipito-frontalis muscle. 2, The orbicularis palpebrarum. 6, The levator labii superioris 7, The levator anguli oris. 8, The zygomaticus minor. 9, The zygomaticus major 10, The masseter. 11, The depressor labii superioris. 13, The orbicularis oris. 15, The depressor anguli oris. 16, The depressor labii inferioris. 18, The sterno-hyoideus. 19, The platysma-myodes. 20, The superior belly of the omo-hyoideus. 21, The sterno-cleido mastoideus. 20, The scalenus medius. 23, The inferior belly of the omo-hyoideus. 24, The trapezius.[5] _Practical Explanation._ The muscle 1, 1, elevates the eyebrows. The muscle 2 closes the eye. The muscle 6 elevates the upper lip. The muscles 7, 8, 9, elevate the angle of the mouth. The muscle 10 brings the teeth together when eating. The muscle 11 depresses the upper lip. The muscle 13 closes the mouth. The muscle 15 depresses the angle of the mouth. The muscle 16 draws down the lower lip. The muscles 18, 19, 20, 23, depress the lower jaw and larynx and elevate the sternum. The muscle 21, when both sides contract, draws the head forward, or elevates the sternum; when only one contracts, the face is turned one side toward the opposite shoulder. The muscles 18, 19, 20, 21, 22, 23, 24, aid in respiration.] [5] In the plates illustrating the muscular system, the names of such muscles are given as are referred to in the paragraph "Practical Explanation." These names need not be committed to memory. If a pupil wishes to acquire a knowledge of the general attachment of the muscles represented in the plates, he can do so by _comparing_ the muscular plate with that of the skeleton, (fig. 28.) _Observation._ When we are sick, and cannot take food, the body is sustained by absorption of the fat. The removal of it into the blood causes the sunken cheek, hollow eye, and prominent appearance of the bones after a severe illness. 158. The number of muscles in the human body is more than five hundred; in general, they form about the skeleton two layers, and are distinguished into superficial and deep-seated muscles. Some of the muscles are voluntary in their motions, or act under the government of the will, as those which move the fingers, limbs, and trunk; while others are involuntary, or act under the impression of their proper stimulants, without the control of the individual, as the heart. _Observations._ 1st. The abdominal muscles are expiratory, and the chief agents for expelling the residuum from the rectum, the bile from the gall bladder, the contents of the stomach and bowels when vomiting, and the mucus and irritating substances from the bronchial tubes, trachea, and nasal passages by coughing and sneezing. To produce these effects they all act together. Their violent and continued action sometimes produces hernia, and, when spasmodic, may occasion ruptures of the different organs. 2d. The contraction and relaxation of the abdominal muscles and diaphragm stimulate the stomach, liver, and intestines to a healthy action, and are subservient to the digestive powers. If the contractility of their muscular fibres is destroyed or impaired, the tone of the digestive apparatus will be diminished, as in indigestion and costiveness. This is frequently attended by a displacement of those organs, as they generally gravitate towards the lower portion of the abdominal cavity, when the sustaining muscles lose their tone and become relaxed. -=-=-=-=-=-=-=-=-=-=-=-= What causes the hollow eye and sunken cheek after a severe sickness? 158. How many muscles in the human system? Into how many layers are they arranged? What is a voluntary muscle? Give examples. What is an involuntary muscle? Mention examples. Give observation 1st, respecting the use of the abdominal muscles? Observation 2d. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 39. A front view of the muscles of the trunk. On the left side the superficial layer is seen; on the right, the deep layer. 1, The pectoralis major muscle. 2, The deltoid muscle. 6, The pectoralis minor muscle. 9, The coracoid process of the scapula. 11, The external intercostal muscle. 12, The external oblique muscle 13, Its aponeurosis. 16, The rectus muscle of the right side. 18, The internal oblique muscle. _Practical Explanation._ The muscle 1 draws the arm by the side, and across the chest, and likewise draws the scapula forward. The muscle 2 elevates the arm. The muscle 6 elevates the ribs when the scapula is fixed, or draws the scapula forward and downward when the ribs are fixed. The muscles 12, 16, 18, bend the body forward or elevate the hips when the muscles of both sides act. They likewise depress the rib in expiration. When the muscles on only one side act, the body is twisted to the same side.] -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 39. Give the function of some of the most prominent muscles, from this figure. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 40. A lateral view of the muscles of the trunk. 3, The upper part of the external oblique muscle. 4, Two of the external intercostal muscles. 5, Two of the internal intercostals. 6, The transversalis muscle. 7, Its posterior aponeurosis. 8, Its anterior aponeurosis. 11, The right rectus muscle. 13, The crest of the ilium, or haunch-bone. _Practical Explanation._ The rectus muscle, 11, bends the thorax upon the abdomen when the lower extremity of the muscle is the fixed point; but when the upper extremity is the fixed point, the effect is to bring forward and raise the pelvis and lower extremities. They likewise depress the ribs in respiration. The transverse muscle, 6, 7, 8, lessens the cavity of the abdomen, and presses the intestines; stomach, and liver upward, against the diaphragm, in expiration.] 3d. The region of the back, in consequence of its extent, is common to the neck, the upper extremities, and the abdomen. The muscles of which it is composed are numerous, and are arranged in six layers. -=-=-=-=-=-=-=-=-=-=-=-= What is represented by fig. 40? Give the function of some of the muscles represented by this figure. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 41 The first, second, and part of the third layer of muscles of the back. The first layer is shown on the right, and the second on the left side. 1, The trapezius muscle. 2, The spinous processes of the vertebræ. 3, The acromion process and spine of the scapula. 4, The latissimus dorsi muscle. 5, The deltoid muscle. 7, The external oblique muscle. 8, The gluteus medius muscle. 9, The gluteus maximus muscle, 11, 12, The rhomboideus major and minor muscles. 15, The vertebral aponeurosis. 16, The serratus posticus inferior muscle. 22, The serratus magnus muscle. 23, The internal oblique muscle. _Practical Explanation._ The muscles 1, 11, 12, draw the scapula back toward the spine. The muscles 11, 12, draw the scapula upward toward the head, and slightly backward. The muscle 4 draws the arm by the side, and backward, The muscle 5 elevates the arm. The muscles 8, 9, extend the thigh on the body. The muscle 1 draws the head back and elevates the chin. The muscle 16 depresses the ribs in expiration. The muscle 22 elevates the ribs in inspiration.] 159. The diaphragm, or midriff, is the muscular division between the thorax and the abdomen. It is penetrated by the oesophagus on its way to the stomach, by the aorta conveying blood toward the lower extremity, and by the ascending vena cava, or vein, on its way to the heart. [Illustration: Fig. 42. A representation of the under, or abdominal side of the diaphragm. 1, 2, 3, 4, The portion which is attached to the margin of the ribs. 8, 10, The two fleshy pillars of the diaphragm, which are attached to the third and fourth lumbar vertebræ. 9, The spinal column. 11, The opening for the passage of the aorta. 12, The opening for the oesophagus. 13, The opening for the ascending vena cava, or vein.] _Observation._ The diaphragm may be compared to an inverted basin, its bottom being turned upward into the thorax, while its edge corresponds with the outline of the edges of the lower ribs and sternum. Its concavity is directed toward the abdomen, and thus, this cavity is very much enlarged at the expense of that of the chest, which is diminished to an equal extent. -=-=-=-=-=-=-=-=-=-=-=-= 159. Describe the diaphragm. What vessels penetrate this muscular septum? -=-=-=-=-=-=-=-=-=-=-=-= 160. "The motions of the fingers do not merely result from the action of the large muscles which lie on the fore-arm, these being concerned more especially in the stronger actions of the hands. The finer and more delicate movements of the fingers are performed by small muscles situated in the palm and between the bones of the hand, and by which the fingers are expanded and moved in all directions with wonderful rapidity." [Illustration: Fig. 43. A front view of the superficial layer of muscles of the fore-arm. 5, The flexor carpi radialis muscle. 6, The palmaris longus muscle. 7, One of the fasciculi of the flexor sublimis digitorum muscle, (the rest of the muscle is seen beneath the tendons of the pintails longus.) 8, The flexor carpi ulnaris muscle. 9, The palmar fascia. 11, The abductor pollicis muscle. 12, One portion of the flexor orevis pollicis muscle. 13, The supinator longus muscle. 14, The extensor ossis metacarpi, and extensor primi internodii pollicis muscles, curving around the lower border of the fore-arm. 15, The anterior portion of the annular ligament, which binds the tendons in their places. _Practical Explanation._ The muscles 5, 6, 8, bend the wrist on the bones of the fore-arm. The muscle 7 bends the second range of finger-bones on the first. The muscle 11 draws the thumb from the fingers. The muscle 12 flexes the thumb. The muscle 13 turns the palm of the hand upward. The muscles 8, 13, 14, move the hand laterally.] [Illustration: Fig. 44. A back view of the superficial layer of muscles of the fore-arm. 5, The extensor carpi radialis longior muscle. 6, The extensor carpi radialis brevior muscle. 7, The tendons of insertion of these two muscles. 8, The extensor communis digitorum muscle. 9, The extensor minimi dlgiti muscle. 10, The extensor carpi ulnaris muscle. 13, The extensor ossis metacarpi and extensor primi internodii muscles, lying together. 14, The extensor secundi internodii muscle; its tendon is seen crossing the two tendons of the extensor carpi radialis longior and brevior muscles. 15, The posterior annular ligament. The tendons of the common extensor muscle of the fingers are seen on the back of the hand, and their mode of distribution on the back of the fingers. _Practical Explanation._ The muscles 5, 6, 10, extend the wrist on the fore-arm. The muscle 8 extends the fingers. The muscle 9 extends the little finger. The muscles 13 extend the metacarpal bone of the thumb, and its first phalanx. The muscle 14 extends the last bone of the thumb. The muscles 10, 13, 14, move the hand laterally.] -=-=-=-=-=-=-=-=-=-=-=-= 160. Where are the muscles situated that effect the larger movements of the hand? That perform the delicate movements of the fingers? Give the use of some of the muscles represented by fig. 43. Those represented by fig. 44. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER IX. PHYSIOLOGY OF THE MUSCLES. 161. The muscles exercise great influence upon the system. It is by their contraction that we are enabled to pursue different employments. By their action the farmer cultivates his fields, the mechanic wields his tools, the sportsman pursues his game, the orator gives utterance to his thoughts, the lady sweeps the keys of the piano, and the young are whirled in the mazy dance. As the muscles bear so intimate a relation to the pleasures and employments of man, a knowledge of the laws by which their action is governed, and the conditions upon which their health depends, should be possessed by all. 162. The peculiar characteristic of muscular fibres is _contractility_, or the power of shortening their substance on the application of stimuli, and again relaxing when the stimulus is withdrawn. This is illustrated in the most common movements of life. Call into action the muscles that elevate the arm, by the influence of the _will_, or mind, (the common stimulus of the muscles,) and the hand and arm are raised; withdraw this influence by a simple effort of the will, and the muscles, before rigid and tense, become relaxed and yielding. 163. The contractile effect of the muscles, in producing the varied movements of the system, may be seen in the bending of the elbow. The tendon of one extremity of the muscle is attached to the shoulder-bone, which acts as a fixed point; the tendon of the other extremity is attached to one of the bones of the fore-arm. When the swell of the muscle contracts, or shortens, its two extremities approach nearer each other, and by the approximation of the terminal extremities of the muscle, the joint at the elbow bends. On this principle, all the joints of the system are moved. This is illustrated by fig. 45. -=-=-=-=-=-=-=-=-=-=-=-= 161-172. _Give the physiology of the muscles._ 161. What are some of the influences exerted by the muscles on the system? 162. What is peculiar to muscular fibres? How is this illustrated? 163. Explain how the movements of the system are effected by the contraction of the muscles. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 45. A representation of the manner in which all of the joints of the body are moved. 1, The bone of the arm above the elbow. 2, One of the bones below the elbow. 3, The muscle that bends the elbow. This muscle is united, by a tendon, to the bone below the elbow, (4,) at the other extremity, to the bone above the elbow, (5,) 6, The muscle that extends the elbow. 7, Its attachment to the point of the elbow. 8, A weight in the hand to be raised. The central part of the muscle 3 contracts, and its two ends are brought nearer together. The bones below the elbow are brought to the lines shown by 9, 10, 11. The weight is raised in the direction of the curved line. When the muscle 6 contracts, the muscle 3 relaxes and the fore-arm is extended.] _Experiments._ 1st. Clasp the arm midway between the shoulder and elbow, with the thumb and fingers of the opposite hand. When the arm is bent, the inside muscle will become hard and prominent, and its tendon at the elbow rigid, while the muscle on the opposite side will become flaccid. Extend the arm at the elbow, and the outside muscle will swell and become firm, while the inside muscle and its tendon at the elbow will be relaxed. -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 45. Give experiment 1st. -=-=-=-=-=-=-=-=-=-=-=-= 2d. Clasp the fore-arm about three inches below the elbow, then open and shut the fingers rapidly, and the swelling and relaxation of the muscles on the opposite sides of the arms, alternating with each other, will be felt, corresponding with the movement of the fingers. While the fingers are bending, the inside muscles swell, and the outside ones become flaccid; and, while the fingers are extending, the inside muscles relax, and the outside ones swell. The alternate swelling and relaxation of antagonist muscles may be felt in the different movements of the limbs. 164. Each fibre of the several muscles receives from the brain, through the nervous filament appropriated to it, a certain influence, called nervous fluid, or stimulus. It is this that induces contraction, while the suspension of this stimulus causes relaxation of the fibres. By this arrangement, the action of the muscular system, both as regards duration and power, is, to a limited extent, under the control of the mind. The more perfect the control, the better the education of the muscular system; as is seen in the graceful, effective, and well-educated movements of musicians, dancers, skaters, &c. 165. The length of time which a muscle may remain contracted, varies. The duration of the contraction of the voluntary muscles, in some measure, is in an inverse ratio to its force. If a muscle has contracted with violence, as when great effort is made to raise a heavy weight, relaxation will follow sooner than when the contraction has been less powerful, as in raising light bodies. 166. The velocity of the muscular contraction depends on the will. Many of the voluntary muscles in man contract with great rapidity, so that he is enabled to utter distinctly fifteen hundred letters in a minute; the pronunciation of each letter requiring both relaxation and contraction of the same muscle, thus making three thousand actions in one minute. But the contraction of the muscles of some of the inferior animals surpasses in rapidity those of man. The race-horse, it is said, has run a mile in a minute; and many birds of prey will probably pass not less than a thousand miles daily. -=-=-=-=-=-=-=-=-=-=-=-= Give experiment 2d. 164. With what is each muscular fibre supplied? What effect has this stimulus on the muscles? 165. how long does a voluntary muscle remain contracted? 166. On what is the velocity of muscular contraction dependent? How many letters may be pronounced in a minute? -=-=-=-=-=-=-=-=-=-=-=-= 167. The functions of the involuntary muscles are necessary the digestion of food, the absorption and circulation of the nutritive fluids. They could not be trusted with safety to the control of the will, lest the passions or the indiscretions of the person should continually avert those operations so necessary to health, and even to life. The Divine Builder of this complicated machine has wisely ordered that the muscles upon which these motions depend, shall act under the impression of their proper stimulants, without the control of the individual. 168. Again, there are certain operations which could not be safely intrusted to the absolute government of the voluntary muscles, or entirely removed from their control. Thus life can be supported only a few minutes without breathing; but it would be impossible to perform the daily vocations of life if we were compelled to breathe at all times, or at perfectly regular intervals. 169. It has been observed that, among men of the same size, a wide difference exists in their strength and activity--qualities which depend upon the size and number of the nerves, the size and activity of the brain, and the education, or training of the muscles. Men having large nerves leading to the muscles, with the brain active, and muscles well trained will perform feats of strength and agility, that other men, of the same size, cannot effect. Rope-dancers, harlequins, and other performers of feats, are persons thus constituted. -=-=-=-=-=-=-=-=-=-=-=-= How many contractions and relaxations of the same muscle? What is said of the rapidity of muscular contractions in other animals? 167. When are the involuntary muscles called into action? Why would it not have been safe to trust these important operations to the exclusive control of the will? 168. Give an instance where some of the muscles act under the government of the will, conjoined with those that are involuntary. 169. On what does the difference in muscular activity and strength depend? -=-=-=-=-=-=-=-=-=-=-=-= 170. Persons with small muscles, and largely developed nervous systems, will sometimes exhibit very great muscular power for a time; but it will not be of long continuance, unless the brain is functionally diseased, as in hysteria, delirium of fever, insanity, &c. Men of large muscles and small nerves can never perform feats of great strength; but they have the power of endurance, and are better capacitated for continued labor. Thus we cannot judge of the ability of persons to make exertions and continue them, by their stature alone. Strength, and the power of endurance, are the result of a combination of well-developed muscles, large nerves, and a full-sized, healthy, and active brain. _Observation._ The muscles of fishes are large, and the nerves distributed to them, comparatively small. The muscles of birds are small, but their fibres are very compact. The nerves appropriated to the muscles that are called into action in flying, are large as well as numerous. 171. The contractile portion of a muscle is, in general, at a distance from the part to be moved. Thus the principal muscles that move the fingers are situated upon the forearm; and when the limb is nearly or quite extended, the angle formed by the part to be moved and the contractile muscles is small. Again, the attachment of the muscles to the part to be moved is near the joint that forms the fulcrum, (fig. 45.) By these arrangements there is a loss of power; but we are compensated for this disadvantage by increased celerity of movement, beauty of form, and adaptation of the limbs to the varied pursuits of man. -=-=-=-=-=-=-=-=-=-=-=-= 170. What is said of those persons who have small muscles and largely developed nervous systems? Of those who have large muscles and small nerves? Upon what do strength and the power of endurance depend? 171. Why is there a loss of power in the action of the muscles? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ The muscle that bends the elbow acts at disadvantage, and this is greatest when the arm is nearly or quite extended, as the angle of action is then least. This disadvantage is further increased by the attachment of the motive muscles near the joint. 172. The number of muscles which are called into action in the movements of the different joints, varies. The hinge-joints, as the elbow, have two sets of muscles--one to bend the joint, the other to extend it. The ball and socket joints, as the shoulder, are not limited to mere flexion and extension. No joint in the system has the range of movement that is possessed by that of the shoulder. By the action of the muscles attached to the arm, it is not only carried upward and forward, but forward and backward. Hence the arm may be moved at any angle, by a combined action of its muscles. _Observation._ "Could we behold properly the muscular fibres in operation, nothing, as a mere mechanical exhibition, can be conceived more superb than the intricate and combined actions that must take place during our most common movements. Look at a person running or leaping, or watch the motions of the eye. How rapid, how delicate, how complicated, and yet how accurate, are the motions required! Think of the endurance of such a muscle as the heart, that can contract, with a force equal to sixty pounds, seventy-five times every minute, for eighty years together, without being weary." _Note._ It would be a profitable exercise for pupils to press their fingers upon prominent muscles, and, at the same time, vigorously contract them, not only to learn their situations, but their use; as the one that bends the arm, 14, fig. 46. -=-=-=-=-=-=-=-=-=-=-=-= How is this illustrated? 172. Do all joints require the same number of muscles, when called into action? How many are called into action in the movement of the elbow? What is their office? What is said of the movement of the ball and socket joint? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 46. An anterior view of the muscles of the body. 1. The frontal swell of the occipito-frontalis. 2, The orbicularis palpebrarum. 3, The levator labli superioris. 4, The zygomaticus major. 5, The zygomaticus minor. 6, The masseter. 7, The orbicularis oris. 8, The depressor labli inferioris. 9. The platysma myodes. 10, The deltoid. 11, The pectoralis major. 12, The latissimus dorsi. 14, The biceps flexor cubiti. 15, The triceps extensor cubiti. 16, The supinator radii longus. 18, The flexor carpi radialis longior. 19, The flexor communis digitorum. 20, The annular ligament. 21, The palmar fascia. 22, The obliquus externus abdominis. 26, The psoas magnus. 27, The adductor longus. 28, The sartorius. 29, The rectus femoris. 30, The vastus externus. 31, The vastus internus. 32, The tendon patellæ. 33, The gastrocnemius. 34, The tibialis anticus. 36, The tendons of the extensor digitorum communis.] [Illustration: Fig. 47. A posterior view of the muscles of the body. 3, The complexus. 4, The splenius. 5, The masseter. 6, The sterno-cleido mastoideus. 7, The trapezius. 8, The deltoid. 10, The triceps extensor. 13, The tendinous portion of the triceps. 14, The anterior edge of the triceps. 15, The supinator radii longus. 17, The extensor communis digitorum. 18, The extensor ossis metacarpi pollicis. 19, The tendons of the extensor communis digitorum. 20, The olecranon process of the ulna and insertion of the triceps. 21, The extensor carpi ulnaris. 22, The extensor communis digitorum. 24, The latissimus dorsi. 25, Its tendinous origin. 26, The obliquus externus. 27, The gluteus medius. 28, The gluteus magnus. 29, The biceps flexor cruris. 30, The semi-tendinosus. 31, 32, The gastrocnemius. 33, The tendo Achillis. _Practical Explanation._ The muscle 1, fig. 46, by its contraction, raises the eyebrows. The muscle 2, fig. 46, closes the eyelids. The muscle 3, fig. 46, elevates the upper lip. The muscles 4, 5, fig. 46, elevate the angles of the mouth. The muscles 6, fig. 46, and 5, fig. 47, bring the teeth together. The muscle 7, fig. 46, closes the mouth. The muscle 8, fig. 46, depresses the lower lip. The muscles 9, fig. 46, and 6, fig. 47, bend the neck forward. The muscles 3, 4, fig. 47, elevate the head and chin. The muscle 22, fig. 46, bends the body forward, and draws the ribs downward. The muscle 11, fig. 46, brings the shoulder forward. The muscle 7, fig. 47, draws the shoulder back. The muscles 10, fig. 46, and 8, fig. 47, elevate the arm. The muscles 11, fig. 46, and 24, fig. 47, bring the arm to the side. The muscle 14, fig. 46, bends the arm at the elbow. The muscle 10, fig. 47, extends the arm at the elbow. The muscles 16, 18, fig. 46, bend the wrist and fingers. The muscle 19 bends the fingers. The muscles 18, 21, 23, fig. 47, extend the wrist. The muscle 23, fig. 47, extends the fingers. The muscles 26, 27, 28, fig. 46, bend the lower limbs on the body, at the hip. The muscle 28, fig. 46, draws one leg over the other, (the position of a tailor when sewing.) The muscles 27, 28, fig. 47, extend the lower limbs on the body, at the hip. The muscles 29, 30, 31, fig. 46, extend the leg at the knee. The muscles 29, 30, fig. 47, bend the leg at the knee. The muscles 34, 36, fig. 46, bend the foot at the ankle, and extend the toes. The muscles 31, 32, 33, fig. 47, extend the foot at the ankle.] _Note._ Let the anatomy and physiology of the muscular system be reviewed, in form of topics, from figs 46, 47, or from the anatomical outline plates No. 3 and 4. CHAPTER X. HYGIENE OF THE MUSCLES 173. _The muscles should be used, in order that the size and strength of these organs may be adequate to the demand made upon them._ It is a law of the system that the action and power of an organ are commensurate, to a certain extent, with the demand made upon it; and it is a law of the muscular system that, whenever a muscle is called into frequent use, its fibres increase in thickness within certain limits, and become capable of acting with greater force; while, on the contrary, the muscle that is little used decreases in size and power. _Illustrations._ 1st. The blacksmith uses and rests the muscles of his arm when striking upon the anvil. They not only increase in size, but become very firm and hard. 2d. The student uses the muscles of the arm but little, in holding his books and pen; they not only become small, but soft. 3d. Let the student leave his books, and wield an iron sledge, and the muscles of his arm will increase in size and firmness. On the other hand, let the blacksmith assume the student's vocation, and the muscles of his arm will become soft and less firm. 174. _When the muscles are called into action, the flow of blood in the arteries and veins is increased._ The increased flow of blood in the arteries and veins, causes a more rapid deposition of the particles of matter of which the muscles are composed. If the exercise is adequate to the power of the system, the deposit of new material will exceed in quantity the particles of matter removed, and both the size and energy of the muscles are increased. But there is a limit to the muscles becoming strong by labor. Sooner or later, man will attain his growth or power; yet by judicious exercise, care, and discreet management, the greatest power of the muscles may be preserved until advanced age. -=-=-=-=-=-=-=-=-=-=-=-= 173-211. _Give the hygiene of the muscles._ 173. What is necessary that muscles may attain size and strength? Give a law of the muscular system. Show this by practical illustrations. 174. Why do muscles increase in size when exercised? -=-=-=-=-=-=-=-=-=-=-=-= 175. _The muscles are lessened in size and diminished in power when the exercise is continued so as to produce a feeling of exhaustion._ The loss of material, in this instance, will exceed the deposition of the atoms of matter. This is seen in the attenuated frames of over-tasked domestic animals, as the horse. The same truth is illustrated by the laborious agriculturist, who, in consequence of too severe toil while gathering the products of the field, frequently diminishes his weight several pounds in a few weeks. Exercise, either for pleasure or profit, may fatigue, yet it should never be protracted to languor or exhaustion, if the individual desires "a green old age." 176. _The same amount of exercise will not conduce to the health of all individuals._ If riding or walking one mile causes slight fatigue, this may be beneficial; while, by travelling two miles, the exhaustion may be highly injurious. Exercise and labor should be adapted to the strength of particular individuals. How little soever the strength, that must be the measure of exertion. Any other rule would be fatal to the hopes of invigorating the system, either by exercise or labor. -=-=-=-=-=-=-=-=-=-=-=-= Is there a limit to the muscles becoming powerful by action? How may the strength of muscles be kept until advanced age? 175. What is the effect when exercise is continued until there is a feeling of exhaustion? Give a practical illustration. What rule is mentioned in regard to exercise? 176. Can all persons take the same amount of exercise? What rule is given as to the amount of exercise? -=-=-=-=-=-=-=-=-=-=-=-= 177. _Relaxation must follow contraction, or, in other words, rest must follow exercise._ The necessity of relaxation, when a muscle has been called into action, is seen in the example of a boy extending his arm with a book in his hand, as a penalty. The boy can keep the arm extended but a short time, make what effort he may. It is also seen in the restlessness and feverish excitement that are evinced by persons gazing on troops during days of review. The same is noted in shopping. Such employments call into action the muscles that support the spinal column in an erect position, and the languor or uneasiness is muscular pain. The long-continued tension of a muscle enfeebles its action, and eventually destroys its contractility. 178. _In school, the small children, after sitting a short time, become restless._ If their position be changed, their imperfectly developed muscles will acquire tone, and will again support the spinal column erect without pain. The necessity for frequent recesses in school, is founded on the organic law of muscular action alternating with rest. The younger and feebler pupils are, the greater the necessity for frequent recesses. We would not have the teacher think that one half of the time should be spent in recesses; or the mother, that her daughter is going to school to play. But we do maintain that recesses should be given, and that they should be short and frequent, especially for small and feeble scholars. 179. _Exhaustion is the inevitable result of continued muscular contraction._ For example, let a lady ply the needle quickly for some hours, and the muscles of the back and right arm will become exhausted, which will be indicated by a sense of weariness in these parts. A change of employment and position calls into action a different set of muscles, and the exhausted organs are relieved. -=-=-=-=-=-=-=-=-=-=-=-= 177. What is said of the contraction and relaxation of the muscles? Give examples of the necessity of relaxing the muscles. 178. Why should not small children be confined in one position for a long time? What evils result from this practice? What class of pupils should have recesses most frequently? 179. What effect has continued muscular contraction? -=-=-=-=-=-=-=-=-=-=-=-= 180. _Much more labor will be accomplished by taking time to relax the exhausted muscles_, or by so changing the employment as to bring into action a new set of muscles; the woodman thus relieves himself, by sawing and splitting alternately. This principle applies to the labor of the horse and ox; and it is also applicable to all kinds of employment. With the invalid convalescing from fever, relapses result from inattention to these laws. When a patient is recovering from sickness, his physician should take care that his exercise be proper, neither too much, too little, nor too long continued. 181. _The muscles of growing youths will not endure so much exercise or labor as those of mature men._ In youth a portion of the vital, or nervous energy of the system, is expended upon the growth of the organs of the body, while in the individual who has attained his growth, this expenditure is not demanded; consequently severe labor or exercise should not be imposed on growing children. _Observation._ In the campaigns of Napoleon Bonaparte, his army was frequently recruited by mere boys. He complained to the French government, because he was not supplied with men of mature years, as the youths could not endure the exertion of his forced marches. 182. _The muscles should be gradually called into action._ These organs in action require more blood and nervous fluid than when at rest. As the circulation of these fluids can only be increased in a gradual manner, it follows, that, when the muscular system has been in a state of rest, it should not suddenly be called into vigorous action. On arising from a bed, lounge, or chair, the first movements of the limbs should be slow, and then gradually increased. _Observation._ if a man has a certain amount of work to perform in nine hours, and his muscles have been in a state of rest, he will do it with less fatigue by performing half the amount of the labor in five hours, and the remainder in four hours. The same principle should be regarded in driving horses and other beasts of burden. -=-=-=-=-=-=-=-=-=-=-=-= 180. How can the greatest amount of labor be secured with the least exhaustion to the muscles? 181. Why should not severe labor be imposed on growing children? 182. How should the muscles be called into action? -=-=-=-=-=-=-=-=-=-=-=-= 183. _The muscles should be rested gradually, when they have been vigorously used._ If a person has been making great muscular exertion in cutting wood, or any other employment, instead of sitting down to rest, he should continue muscular action, for a short time, by some moderate labor or amusement. 184. _If the system has been heated by muscular action, and the skin is covered with perspiration, avoid sitting down_ "to cool" in a current of air; rather, put on more clothing, and continue to exercise moderately. In instances when severe action of the muscles has been endured, bathing and rubbing the skin of the limbs and joints that have been used, are of much importance. The laboring agriculturist and industrious mechanic, by reducing to practice this suggestion, would thus prevent soreness of the muscles, and stiffness of the joints. 185. _The muscles should be abundantly supplied with pure blood._ This state of the circulating fluid requires a healthy condition of the digestive apparatus, and that the skin should be kept warm by proper clothing, clean by bathing, and be acted upon by pure air and good light; the movements of the ribs and diaphragm should be unrestricted, and the lungs should have ample volume and be supplied with pure air. In all instances, muscular power is greatest when the preceding conditions exist, as the muscles are then stimulated by pure blood; consequently, it is of practical importance to the mechanic, the farmer, the man of leisure, and not less so to the ladies, to observe these conditions, whatever vocation of life they pursue. -=-=-=-=-=-=-=-=-=-=-=-= 183. How should the muscles be rested when they have been vigorously used? 184. What precaution is given when the skin is covered with perspiration? How may soreness of the muscles, consequent upon severe action, be prevented? 185. Should the muscles be supplied with pure blood? When is muscular power the greatest? -=-=-=-=-=-=-=-=-=-=-=-= 186. _The muscles should be used in pure air._ The purer the air we breathe, the more stimulating the blood supplied to the muscles, and the longer they can be used in labor, walking, or sitting, without fatigue and injury; hence the benefit derived in thoroughly ventilating all inhabited rooms. For the same reason, if the air of the sick-room is pure, the patient will sit up longer than when the air is impure. _Observation._ It is a common remark that sick persons will sit up longer when riding in a carriage, than in an easy chair in the room where they have lain sick. In the one instance, they breathe pure air; in the other, usually, a confined, impure air. 187. _The muscles should be exercised in the light._ Light, particularly that of the sun, exercises more or less influence on man and the inferior animals as well as on plants. Both require the stimulus of this agent. Shops occupied by mechanics, kitchens, and sitting-rooms, should be well lighted, and situated on the sunny side of the house. Cellar kitchens and underground shops should be avoided. For similar reasons, students should take their exercise during the day, rather than in the evening, and, as much as possible, laborers should avoid night toil. _Illustrations._ Plants that grow in the shade, as under trees, or in a dark cellar, are of lighter color and feebler than those that are exposed to the light of the sun. Persons that dwell in dark rooms are paler and less vigorous than those who inhabit apartments well lighted, and exposed to the rays of the sun. -=-=-=-=-=-=-=-=-=-=-=-= 186. Why should the muscles be used in pure air? Give a common observation. 187. What effect has light on the muscular system? What should the laborer avoid? Why should not students take their daily exercise in the evening? How is the influence of solar light illustrated? -=-=-=-=-=-=-=-=-=-=-=-= 188. _Exercise should be regular and frequent._ The system needs this means of invigoration as regularly as it does new supplies of food. It is no more correct that we devote several days to a _proper_ action of the muscles, and then spend one day inactively, than it is to take a _proper_ amount of food for several days, and then withdraw this supply for a day. The industrious mechanic and the studious minister suffer as surely from undue confinement as the improvident and indolent. The evil consequences of neglect of exercise are gradual, and steal slowly upon an individual. But sooner or later they are manifested in muscular weakness, dyspepsia, and nervous irritability. _Observation._ The custom among farmers of enduring severe and undue toil for several successive days, and then spending one or two days in idleness to _rest_, is injudicious. It would be far better to do less in a day, and continue the labor through the period devoted to idleness, and then no rest will be demanded. 189. _Every part of the muscular system should have its appropriate share of exercise._ Some employments call into exercise the muscles of the upper limbs, as shoe-making; others, the muscles of the lower limbs; while some, the muscles of both upper and lower limbs, with those of the trunk, as farming. In some kinds of exercise, the lower limbs are mainly used, as in walking; in others, the upper limbs; and again, the muscles of the trunk, together with those of the upper and lower limbs, as in archery, quoits, playing ball. Those trades and kinds of exercise are most salutary, in which all the muscles have their due proportion of action, as this tends to develop and strengthen them equally. Thus labor upon the farm and domestic employment are superior as vocations, and archery, quoits, and dancing, if the air is pure, among the pastimes. For sedentary persons, that kind of exercise is best which calls into action the greatest number of muscles. -=-=-=-=-=-=-=-=-=-=-=-= 188. How should exercise be taken? What is said respecting irregular exercise? Are the consequences of neglected exercise immediately apparent? What practical observation is given? 189. Should every muscle have its due amount of exercise? Mention some employments that only call into action the muscles of the upper limbs. Those of the lower limbs, those of the trunk and limbs. Mention, in the different pastimes, what muscles are called into action. -=-=-=-=-=-=-=-=-=-=-=-= 190. _The proper time for labor or exercise should be observed._ This is modified by many circumstances. As a general rule, the morning, when the air is pure and the ground dry, is better than the evening; for then, the powers of the body are greatest. Severe exercise and labor should be avoided immediately before or after eating a full meal, for the energies of the system are then required to perform the digestive function. For similar reasons, it is not an appropriate time for energetic muscular action immediately before or after severe mental toil, as the powers of the system are then concentrated upon the brain.[6] [6] It appears to be a fact, that no two important organs can be called into intense action at the same time, without injury to both, as well as to the general system. This arises from the circumstance that an organ, when in functional action, attracts fluids (sanguineous and nervous) from other organs of the system. Except in a few instances of high health in youth, the power of the system is not adequate to supply more than one organ in action with the appropriate fluids at the same time. -=-=-=-=-=-=-=-=-=-=-=-= What kinds of exercise are best? 190. What rule is given respecting the time for exercise? 191. Why do the muscles require sleep? What is the effect of an inversion of the law of rest? -=-=-=-=-=-=-=-=-=-=-=-= 191. _The muscles require sleep to restore their expended energies._ Among the arrangements of creative wisdom, no one harmonizes with the wants of the system more than the alternation of day and night. The natural inclination of man to sleep, is in the stilly hour of night, when all nature reposes, and to be in action during the light of day. An inversion of this law of rest causes greater exhaustion of the system than the same amount of exertion during daylight. This is illustrated by the wearied and exhausted condition of watchers, night-police, and other individuals who spend a part of the night in some active business of life. 192. _The muscles should not be compressed._ Compression prevents the blood from passing to the muscles with freedom; consequently, they are not supplied with material to renovate and promote their growth. Again, pressure stimulates the lymphatics to action; and by the increased activity of these vessels the muscles are attenuated. In the case of a man with a fractured limb, the muscles are not only enfeebled by inaction, but diminished in size by compression from the dressing. Limbs enfeebled in this way will not recover their size, tone, and strength, until the bandages are removed, and a proper amount of exercise taken. 193. The pressure of tight dresses, under the name of a "snug fit," enfeebles the muscles of the back, and is a common cause of projecting shoulders and curvature of the spinal column. Thus every appendage to the dress of ladies which prevents free motion of the muscles of the chest and spinal column, weakens the muscles thus restrained, and not only prevents the proper expansion of the lungs, but, by weakening the muscles which sustain the spine, induces curvature and disease. Whalebone, wood, steel, and every other unyielding substance, should be banished from the toilet, as enemies of the human race. 194. _The mind exerts a great influence upon the tone and contractile energy of the muscular system._ A person acting under a healthy mental stimulus will make exertion with less fatigue than he would without this incentive. For this reason, a sportsman will pursue his game miles without fatigue, while his attendant, not having any mental stimulus, will become weary. Again, if the sportsman spends some hours in pursuit of his favorite game without success, a feeling of languor creeps over him; but while he is thus fatigued and dispirited, let him catch a glimpse of the game,--his wearied feelings are immediately dissipated, and he presses on with renewed energy and recruited strength. -=-=-=-=-=-=-=-=-=-=-=-= 192. Why should not the muscles be compressed? 193. What is the effect of tight clothing upon the muscles? 194. What is said of the influence of the mind upon muscular activity? Give an illustration of mental stimulus coöperating with muscular activity in the case of a sportsman. -=-=-=-=-=-=-=-=-=-=-=-= 195. This principle was well illustrated in the retreat from Russia of the defeated and dispirited French army. When no enemy was near, they had hardly strength sufficient to carry their arms; but no sooner did they hear the report of the Russian guns, than new life seemed to pervade them, and they wielded their weapons powerfully until the foe was repulsed, then there was a relapse to weakness, and prostration followed. It is thus with the invalid when riding for his health;--relate an anecdote, or excite this mental stimulus by agreeable conversation, and much benefit will accrue from the ride to the debilitated person. So it is in the daily vocations of life; if the mind have some incentive, the tiresomeness of labor will be greatly diminished. Let an air of cheerfulness ever pervade our every employment, and, like music, "it sweetens toil." 196. Facts illustrative of the inutility of calling the muscles into action, without the coöperation of the mind, are seen in the spiritless aspect of many of our boarding school processions, when a walk is taken merely for exercise, without having in view any attainable object. But present to the mind a botanical or geological excursion, and the saunter will be exchanged for the elastic step, the inanimate appearance for the bright eye and glowing cheek. The difference is, simply, that, in the former case, the muscles are obliged to work without that full nervous impulse so essential to their energetic action; and that, in the latter, the nervous influence is in full and harmonious operation. -=-=-=-=-=-=-=-=-=-=-=-= 195. Give an illustration of mental stimulus coöperating with muscular activity in the case of the dispirited French army in their retreat from Russia. How can a union of mental impulse and muscular action be beneficial to an invalid? Does this same principle apply to those who labor? 196. Give an instance of the different effects produced by the absence and presence of the mental stimulus. -=-=-=-=-=-=-=-=-=-=-=-= 197. It must not, however, be supposed that a walk simply for the sake of exercise can never be beneficial. Every one, unless prevented by disease, should consider it a duty to take exercise every day in the open air; if possible, let it be had in combination with harmonious mental exhilaration; if not, let a walk, in an erect position, be made so brisk as to produce rapid respiration and circulation of the blood, and in a dress that shall not interfere with free motions of the arms and free expansion of the chest. _Observation._ The advantages of combining harmonious mental excitement, with muscular activity, is thus given by Dr. Armstrong:-- "_In whate'er you sweat, Indulge your taste._ Some love the manly toils The tennis some, and some the graceful dance; Others, more hardy, range the purple heath Or naked stubble, where, from field to field, The sounding covies urge their lab'ring flight, Eager amid the rising cloud to pour The gun's unerring thunder; and there are Whom still the mead of the green archer charm. _He chooses best whose labor entertains His vacant fancy most; the toil you hate Fatigues you soon, and scarce improves your limbs._" -=-=-=-=-=-=-=-=-=-=-=-= 197. May not a walk, simply as an exercise, be beneficial? What is preferred? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XI. HYGIENE OF THE MUSCLES, CONTINUED. 198. _The erect attitude lessens the exhaustion of the muscles._ A person whose position is erect will stand longer, walk further, and perform more labor, than an individual whose position is stooping, but equal in all other respects. The manly port in an erect attitude, depends chiefly upon the action of the muscles of the back; and it follows that the fewer the muscles in a state of tension, the less the draught upon the nervous system, and the less its exhaustion. Another advantage which attends the erect position is, the trunk and head are balanced upon the bones and cartilages of the spinal column. If the body slightly incline forward, the muscles attached to the posterior side of the spine, by a gentle contraction, will bring it to the perpendicular, and even incline it backward. This is immediately removed by a slight contraction of the muscles upon the anterior side of the spinal column. 199. In the erect position, there is a constant slight oscillation of the body backward and forward, like the movement of a pendulum; while, in the stooping posture, the muscles on the posterior side of the spinal column are kept in a state of continued tension and contraction, to prevent the body from falling forward. This enfeebles the muscles of the back, and exhausts the nervous energy, while the erect position favors their development and power, because there is an alternate contraction and relaxation of the muscles. Again, in the stooping position, the lower limbs are curved at the knee. In this attitude, there is a constant tension of the muscles of the lower extremities, which produces muscular exhaustion. -=-=-=-=-=-=-=-=-=-=-=-= 198. Why will a person who stands erect walk further, and perform more labor, than if he assumed the stooping posture? 199. Why are the muscles of the back so soon exhausted in the stooping position? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 48. 1, A perpendicular line from the centre of the feet to the upper extremity of the spinal column, where the head rests. 2, 2, 2, The spinal column, with its three natural curves. Here the head and body are balanced upon the spinal column and joints of the lower extremities, so that the muscles are not kept in a state of tension. This erect position of the body and head is always accompanied with straight lower limbs.] [Illustration: Fig. 49. 1, A perpendicular line from the centre of the feet. 2, Represents the unnatural curved spinal column, and its relative position to the perpendicular, 1. The lower limbs are curved at the knee, and the body is stooping forward. While standing in this position, the muscles of the lower limbs and back are in continued tension, which exhausts and weakens them.] -=-=-=-=-=-=-=-=-=-=-=-= What is represented by figs. 48 and 49? -=-=-=-=-=-=-=-=-=-=-=-= 200. When it is necessary to call into action a part of the muscles of the system in the performance of any duty, as those of the lower limbs in walking, if the muscles of other parts are in a state of inaction, the influence of the nervous system can be determined in an undivided manner upon those parts of the lower limbs in action; hence they will not so soon become wearied or exhausted, as when this influence is divided between a greater number of muscles. In performing any labor, as in speaking, reading, singing, mowing, sewing, &c., there will be less exhaustion, and the effort can be longer maintained in the erect position of the body and head, than in a stooping attitude. _Experiment._ Hold in each hand a pail of water or equal weights, in a stooping posture, as long as it can be done without much suffering and injury. Again, when the muscular pain has ceased, hold the same pails of water, for the same length of time, in an erect posture, and note the difference in the fatigue of the muscles. 201. If the stooping posture is acquired in youth, we are quite certain of seeing the deformed shoulders in old age. Hence the importance of duly exercising the muscles of the back, for when they are properly developed, the child can and will stand erect. In this attitude, the shoulders will be thrown back, and the chest will become broad and full. 202. Pupils, while standing during recitations, often inadvertently assume the attitude represented by fig. 49, and it is the duty of teachers to correct this position when assumed. When a child or adult has contracted a habit of stooping, and has become round-shouldered, it can be measurably, and generally, wholly, remedied by moderate and repeated efforts to bring the shoulders back, and the spinal column in an erect position. This deformity can and should be remedied in our schools. It may take months to accomplish the desired end, yet it can be done as well under the direction of the kind instructor, as under the stern, military drill sergeant, who never fails to correct this deformity among his raw recruits. -=-=-=-=-=-=-=-=-=-=-=-= 200. What suggestion when it is necessary to call into action a part of the muscular system? Give the experiment that illustrates this principle. 201. Why should a child he taught to stand erect? 202. How can round shoulders acquired by habit be remedied? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 50. A proper position in sitting.] 203. _The child should be taught to sit erect when employed in study or work._ This attitude favors a healthy action of the various organs of the system, and conduces to beauty and symmetry of form. Scholars are more or less inclined to lean forward and place the elbow on the table or desk, for support and this is often done when their seats are provided with backs. Where there is a predisposition to curvature of the spine, no position is more unfavorable or more productive of deformities than this; for it is usually continued in one direction, and the apparent deformity it induces is a projection of the shoulders. If the girl is so feeble that she cannot sit erect, as represented by fig. 50, let her stand or recline on a couch; either is preferable to the position represented by fig. 51. In furnishing school-rooms, care should be taken that the desks are not so low as to compel the pupils to lean forward in examining their books. -=-=-=-=-=-=-=-=-=-=-=-= 203. Why should the erect attitude be assumed in sitting? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 51. An improper position in sitting.] 204. _The muscles, when exhausted, cannot endure continued effort._ When the energies of the muscular system have been expended by severe and long-continued exercise, or the brain and nervous system prostrated by protracted mental effort, the muscles are unfitted to maintain the body erect in standing or sitting for a long time, as the nervous system, in its exhausted state, cannot supply a sufficient amount of its peculiar influence to maintain the supporting muscles of the body and head in a state of contraction. Hence, a child or adult, when much fatigued, should not be compelled to stand or sit erect in one posture, but should be permitted to vary the position frequently, as this rests and recruits both the muscular and the nervous system. 205. _A slight relaxation of the muscles tends to prevent their exhaustion._ In walking, dancing, and most of the mechanical employments, there will be less fatigue, and the movements will be more graceful, when the muscles are slightly relaxed. When riding in cars or coaches, the system does not suffer so severely from the jar if there is a slight relaxation of the muscles, as when they are in a state of rigid contraction. _Experiments._ Attempt to bow with the muscles of the limbs and trunk rigid, and there will be a stiff bending of the body only at the hip-joint. On the other hand, attempt to bow with the muscles moderately relaxed; the ankle, the knee, and the hip-joint will slightly bend, accompanied with an easy and graceful curve of the body. 206. The muscles when relaxed, together with the yielding character of the cartilage, and the porous structure of the ends of the bones that form a joint, diffuse or deaden the force of jars, or shocks, in stepping suddenly down stairs, or in falling from moderate heights. Hence, in jumping or falling from a carriage, or any height, the shock to the organs of the system may be obviated in the three following ways: 1st. Let the muscles be relaxed, not rigid. 2d. Let the limbs be bent at the ankle, knee, and hips; the head should be thrown slightly forward, with the trunk a little stooping. 3d. Fall upon the toes, not the heel. -=-=-=-=-=-=-=-=-=-=-=-= 204. When are the muscles unfitted to maintain the system erect either in standing or sitting? What is necessary when this condition of the system exists? 205. Why should the muscular system be slightly relaxed in walking, &c.? Give illustrative experiments. 206. What is the reason that we do not feel the jar in falling from a moderate height? -=-=-=-=-=-=-=-=-=-=-=-= _Experiments._ Stand with the trunk and lower limbs firm, and the muscles rigid; then jump a few inches perpendicularly to the floor, and fall upon the heels. Again, slightly bend the limbs, jump a few inches, and fall upon the toes, and the difference in the force of the shock, to the brain and other organs, will be readily noticed. 207. _The muscles require to be educated, or trained._ The power of giving different intonations in reading, speaking, singing, the varied and rapid executions in penmanship, and all mechanical or agricultural employments, depend, in a measure, upon the education of the muscles. In the first effort of muscular education, the contractions of the muscular fibres are irregular and feeble, as may be seen when the child begins to walk, or in the first efforts of penmanship. 208. _Repetition of muscular action is necessary._ To render the action of the muscles complete and effective, they must be called into action repeatedly and at proper intervals. This education must be continued until not only each muscle, but every fibre of the muscle, is fully under the control of the will. In this way persons become skilful in every employment. In training the muscles for effective action, it is very important that correct movements be adopted at the commencement. If this is neglected, the motions will be constrained and improper, while power and skill will be lost. -=-=-=-=-=-=-=-=-=-=-=-= How is this shown by experiment? 207. Upon what do the different intonations of sound or mechanical employments depend? Why are the first efforts in educating the muscles indifferent or irregular? 208. Why is repetition of muscular action necessary? Why is it important that correct movements be adopted in the first efforts of muscular education? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ If a boy, while learning to mow, is allowed to swing his scythe in a stooping position, twisting his body at every sweep of the scythe, he will never become an easy, efficient mower. Proper instruction is as necessary in many of the agricultural branches as in the varied mechanical employments. [Illustration: Fig. 52. An improper, but not an unusual position, when writing.] [Illustration: Fig. 53. A proper position, when writing.] 209. _Good penmanship requires properly trained muscles._ To a deficient analysis of the movements of the arm, hand, and fingers, on the part of teachers and pupils in penmanship, together with an improper position in sitting, is to be ascribed the great want of success in acquiring this art. The pen should be held loosely, and when the proper position is attained, the scholar should make an effort to imitate some definite copy as nearly as possible. The movements of the fingers, hand, and arm, necessary to accomplish this, should be made with ease and rapidity, striving, at each effort, to imitate the copy more nearly. -=-=-=-=-=-=-=-=-=-=-=-= How is this illustrated? 209. Why have so many pupils failed in acquiring good penmanship? -=-=-=-=-=-=-=-=-=-=-=-= 210. When the arm, hand, and fingers are rigid, the large muscles, that bend and extend these parts, are called into too intense action. This requires of the small muscles, that produce the lateral movements, which are essential to rapidity in writing, an effort which they cannot make, or can with difficulty accomplish. _Experiment._ Vigorously extend the fingers by a violent and rigid contraction of the muscles upon the lower part of the arm, and the lateral movement which is seen in their separation cannot be made. But gently extend the fingers, and their oblique movements are made with freedom. 211. An individual who is acquainted with the laws of health, whose muscles are well trained, will perform a certain amount of labor with less fatigue and waste to the system, than one who is ignorant of the principles of hygiene, and whose muscles are imperfectly trained. Hence the laboring poor have a deep interest in acquiring a knowledge of practical physiology, as well as skill in their trade or vocation. It is emphatically true to those who earn their bread by the "sweat of their brow," that "knowledge is power." -=-=-=-=-=-=-=-=-=-=-=-= 210. What is said of the lateral and oblique movements of the arm, hand, and fingers in writing? How is this shown by experiment? 211. Why is the study of physiology and hygiene of utility to the laborer? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XII. THE TEETH. 212. The teeth, in composition, nutrition, and growth, are different from other bones of the body. They vary in number at different periods of life, and, unlike other bones, they are exposed to the immediate action of atmospheric air and foreign substances. The bones of the system, generally, when fractured, unite; but there is never a permanent union of a tooth when broken. ANATOMY OF THE TEETH. 213. The TEETH are attached to the upper and lower jaw-bone, by means of bony sockets, called _al´ve-o-lar_ processes. These give great solidity to the attachment of the teeth, and frequently render their extraction difficult. The gums, by their fibrous, fleshy structure, serve to fix the teeth more firmly in the jaw. _Observation._ When a _permanent_ tooth is extracted, these bony processes are gradually absorbed, so that in advanced age there remains only the jaw-bone covered by the lining membrane of the gum. This accounts for the narrow jaw and falling in of the lips in old age. Frequently, a piece of the alveolar process comes out with the tooth when extracted, and the dentist has then the credit of "breaking the jaw." No great injury results from the removal of the process in this manner. -=-=-=-=-=-=-=-=-=-=-=-= 212. What is said of the teeth? In what respect do they differ from other bones of the body? 213-218. _Give the anatomy of the teeth._ 213. What confines the teeth in the jaw-bone? What becomes of the socket when a tooth is removed? What effect has this absorption upon the jaw and lips? -=-=-=-=-=-=-=-=-=-=-=-= 214. The teeth are formed in the interior of the jaws, and within _dent´al cap´sules_, (membranous pouches,) which are enclosed within the substance of the bone, and present in their interior a fleshy bud, or granule, from the surface of which exudes the ivory, or the bony part of the tooth. In proportion as the tooth is formed, it rises in the socket, which is developed simultaneously with the tooth, and passes through the gum, and shows itself without. [Illustration: Fig. 54. 1, The body of the lower jaw. 2, Ramus, or branch of the jaw, to which the muscles that move it are attached. 3, 3, The processes which unite the lower jaw with the head. _i_, The middle and lateral incisor tooth of one side. _b_, The bicuspid teeth. _c_, The cuspids, or eye teeth. m, The three molar teeth. A, shows the relation of the permanent to the temporary teeth.] 215. The first set, which appears in infancy, is called _tem´po-ra-ry_, or milk teeth. They are twenty in number; ten in each jaw. Between six and fourteen years of age, the temporary teeth are removed, and the second set appears, called _per´ma-nent_ teeth. They number thirty-two, sixteen in each jaw. -=-=-=-=-=-=-=-=-=-=-=-= 214. Where and how are the teeth formed? Explain fig. 54. 215. What are the first set called? How many in each jaw? The second set? How many in number? -=-=-=-=-=-=-=-=-=-=-=-= 216. The four front teeth in each jaw are called _in-ci´sors_, (cutting teeth;) the next tooth in each side, the _cus´pid_, (eye tooth;) the next two, _bi-cus´pids_, (small grinders;) the next two, _mo´lars_, (grinders.) The last one on each side of the jaw is called a _wisdom tooth_, because it does not appear until a person is about twenty years old. The incisors, cuspids, and bicuspids, have each but one root. The molars of the upper jaw have three roots, while those of the lower jaw have but two. [Illustration: Fig. 55. The permanent teeth of the upper and lower jaw. _a_, _b_, The incisors. _c_, The cuspids. _d_, _e_, The bicuspids. _f_, _g_, The molars, (double teeth.) _h_, The wisdom teeth.] _Observation._ The shape of the teeth in different species of animals is adapted to the kind of food on which they subsist. Those animals that feed exclusively on flesh, as the lion, have the cuspids, or canine teeth, largely developed, and the molars have sharp cutting points. Those animals that feed on grass and grain, as the horse and the sheep, have their molar teeth more rounded and flat on the crown. The human teeth are adapted to feed on fruits, grain, or flesh, as they are less pointed than those of the cat, and more pointed than those of the sheep. -=-=-=-=-=-=-=-=-=-=-=-= 216. Give the names of the permanent teeth. What teeth have but one root, or "fang"? How many roots have the molars of the upper jaw? Of the lower jaw? What is said of the shape of the teeth in different species of animals? -=-=-=-=-=-=-=-=-=-=-=-= 217. The teeth are composed principally of two substances--the _i´vo-ry_ and the _en-am´el_. The internal part of the tooth or the ivory, is harder and more enduring than bone, and forms the body of the tooth. The enamel is remarkable for its hardness, and varies somewhat in color with the age, temperament, habits, and manner of living of different individuals. When any part of the enamel is destroyed, it is never regenerated. [Illustration: Fig. 56. A side view of the body and enamel of a front tooth.] [Illustration: Fig. 57. A side view of a molar tooth. 1, The enamel. 2, The body of the tooth. 3, The cavity in the crown of the tooth that contains the pulp. 4, A nerve that spreads in the pulp of the tooth. 5, An artery that ramifies in the pulp of the tooth.] 218. Each tooth is divided into two parts, namely, _crown_ and _root_. The crown is that part which protrudes from the jaw-bone and gum, and is covered by the highly polished enamel. The root, or "fang," is placed in the sockets of the jaw, and consists of bony matter. Through this bony substance several small vessels pass, to aid in the growth and also in the removal of the tooth. There are, beside these vessels, small white cords passing to each tooth, called _nerves_. (See fig. 57.) When these nerves are diseased, we have the toothache. -=-=-=-=-=-=-=-=-=-=-=-= 217. Give the structure of the teeth. What is said of the enamel? 218. Into how many parts are the teeth divided? Describe the crown. The root. What vessels pass through the bony matter? What is their use? -=-=-=-=-=-=-=-=-=-=-=-= PHYSIOLOGY OF THE TEETH. 219. The use of the teeth is twofold. 1st. By the action of the incisors the food is divided, while the molars grind or break down the more solid portions of it. By these processes, the food is prepared to pass more easily and rapidly into the stomach. 220. In the mastication of food there are two movements of the lower jaw--the action by which the teeth are brought together, and the lateral motion. In the former, the food is cut or divided, the jaws acting like shears. This movement is produced by the action of two large muscles situated on each side of the head and face. _Observation._ The muscles attached to the lower jaw are of great strength; by their action alone, some persons are enabled to bite the hardest substances. By putting the fingers upon the side of the head above and in front of the ears, and upon the face above the angle of the jaw, while masticating food, the alternate swelling and relaxation of these muscles will be clearly felt. 221. The lateral, or grinding movement of the teeth, is produced by the action of a strong muscle that is attached to the lower jaw on the inside. _Observation._ Those animals that live solely on flesh, have only the cutting, or shear-like movement of the jaws. Those that use vegetables for food, have the grinding motion; while man has both the cutting and grinding movement. -=-=-=-=-=-=-=-=-=-=-=-= 219-222. _Give the physiology of the teeth._ 219. Give one of the functions of the teeth. 220. How many movements of the lower jaw in masticating food? What effect has the first movement upon the food? How produced? What is the character of the masticating muscles? 221. How is the grinding motion of the teeth produced? What is said of the movements of the teeth in different animals? -=-=-=-=-=-=-=-=-=-=-=-= 222. 2d. The teeth aid us in articulating with distinctness certain letters and words. An individual who has lost his front teeth cannot enunciate distinctly certain letters called dental. Again, as the alveolar processes are removed by absorption soon after the removal of the teeth, the lips and cheeks do not retain their former full position, thus marring, in no slight degree, the symmetry of the lower part of the face. Consequently, those simple observances that tend to the preservation of the teeth are of great practical interest to all persons. HYGIENE OF THE TEETH. 223. _To preserve the teeth, they must be kept clean._ After eating food, they should be cleansed with a brush and water, or rubbed with a piece of soft flannel, to prevent the _tartar_ collecting, and to remove the pieces of food that may have lodged between them. Toothpicks may be useful in removing any particles inaccessible to the brush. They may be made of bone, ivory, or the common goose-quill. Metallic toothpicks should not be used, as they injure the enamel. 224. _The mouth should be cleansed with pure tepid water at night, as well as in the morning_; after which the teeth should be brushed upward and downward, both on the posterior and anterior surfaces. It may be beneficial to use refined soap, once or twice every week, to remove any corroding substance that may exist around the teeth; care being taken to thoroughly rinse the mouth after its use. 225. _Food or drink should not be taken into the mouth when very hot or very cold._ Sudden changes of temperature will crack the enamel, and finally produce decayed teeth. -=-=-=-=-=-=-=-=-=-=-=-= 222. What is another use of the teeth? 223-232. _Give the hygiene of the teeth._ 223. How can the teeth be preserved? By what means? 224. How often should they be cleansed? 225. What is said of very hot or cold drinks? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ On this account, smoking is pernicious, because the teeth are subjected to an alternate inhalation of both cold and warm air. 226. _The temporary teeth should be removed as soon as they become loose._ If a permanent tooth makes it appearance before the first is removed, or has become loose, the milk tooth, although not loose, should be removed without delay. This is necessary that the second set of teeth may present a regular and beautiful appearance. 227. _In general, when the permanent teeth are irregular, one or more should be removed._ If the teeth are crowded and irregular, in consequence of the jaw being narrow and short, or when they press so hard upon each other as to injure the enamel, remove one or more to prevent their looking unsightly, and in a few months the remaining teeth, with a little care, will fill the spaces. _Observation._ When it is necessary to remove a tooth, apply to some skilful operator. It requires as much skill and knowledge to extract teeth _well_, as it does to amputate a limb; yet some persons, who possess strong arms, will obtain a pair of forceps, or a tooth-key, and hang out the sign of "surgeon-dentist," although ignorant of the principles that should guide them. 228. _It is not always necessary to have teeth extracted when they ache._ The nerve, or the investing membrane of the root, may be diseased, and the tooth still be sound. In such instances, the tooth should not be extracted, but the diseased condition may be remedied by proper medication. There are many sound teeth, that become painful, as already mentioned, which are unnecessarily removed. -=-=-=-=-=-=-=-=-=-=-=-= Why is smoking injurious to the teeth? 226. What remark respecting the temporary teeth? 227. What remarks respecting the permanent teeth? Do those persons that extract teeth require skill as well as knowledge? 228. Why should not teeth be extracted at all times when they are painful? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ Dr. H. M., of Belfast, Me., related to me that an individual in that vicinity had his teeth, (all of them sound,) on one side of the lower jaw, extracted by an ignoramus of a "tooth-puller," and this without any relief from pain. The disease was tic douloureux, which was relieved by Dr. M. 229. _The preservation of the teeth requires that they be frequently examined._ When a part of the enamel is removed, and a small portion of the body of the tooth has become carious, in many instances such teeth may be preserved from further decay by having them filled or "plugged" with _gold foil_. All amalgams, pastes, and cheap patent articles for filling, should be avoided, if you would preserve both the teeth and the general health. 230. The practice of cracking nuts with the teeth, or of lifting heavy bodies, and the constant habit of biting thread, should be avoided, as they finally destroy the enamel. 231. _All acidulated drinks and mineral waters, that "set the teeth on edge," are injurious._ All tooth-powders and washes that contain any article that is acid, corrosive, or grinding, should be banished from the toilet. Tobacco is not a preservative of the teeth. It contains "grit," which wears away the enamel; beside, when chewed, it debilitates the vessels of the gums, turns the teeth yellow, and renders the breath and the appearance of the mouth disagreeable. 232. Healthy persons have generally sound teeth, while feeble persons have decayed teeth. For this reason, we should try to learn and practise the few simple rules that promote health. -=-=-=-=-=-=-=-=-=-=-=-= Give an illustration of the removal of sound teeth. 229. How may decaying teeth be preserved? What should be avoided in the filling of teeth? 230. What practices should also be avoided? 231. What is said of acidulated drinks? What effect has the chewing of tobacco upon the teeth? 232. What is one reason for preserving health? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XIII. THE DIGESTIVE ORGANS. 233. From the earliest existence of the human system to the last ray of life, change is impressed upon it by the Giver of this curious fabric. New atoms of matter are deposited, while the old and now useless particles are constantly removed. The material necessary to sustain the growth of the body in early life, and also to repair the waste that is unceasing to animal existence, is the food we eat. 234. Food, animal or vegetable, contains most of the elements of the different tissues of the system, yet it must undergo certain essential alterations before it can become a part of the body. The first change is effected by the action of the _Digestive Organs_. ANATOMY OF THE DIGESTIVE ORGANS 235. The DIGESTIVE ORGANS are the _Mouth_, _Teeth_,[7] _Sal´i-va-ry Glands_, _Phar´ynx_, _OE-soph´a-gus_, (gullet,) _Stom´ach_, _In-tes´tines_, (bowels,) _Lac´te-als_, (milk, or chyle vessels,) _Tho-rac´ic Duct_, _Liv´er_, and the _Pan´cre-as_, (sweetbread.) [7] See Chapter XII. -=-=-=-=-=-=-=-=-=-=-=-= 233. What is impressed upon the human system from its earliest existence? What maintains this change? 234. Has animal or vegetable food any resemblance to the different tissues of which it finally forms a part? By what organs is the first change in the food effected? 235-258. _Give the anatomy of the digestive organs._ 235. Name them. 236. Describe the mouth. -=-=-=-=-=-=-=-=-=-=-=-= MOUTH is an irregular cavity, which contains the instruments of mastication and the organs of taste. It is bounded in front by the lips; on each side by the internal surface of the cheeks; above, by the _hard palate_ (roof of the mouth) and teeth of the upper jaw; below, by the tongue and teeth of the lower jaw; behind, it is continuous with the pharynx, but is separated from it by a kind of movable curtain, called the _soft palate_. This may be elevated or depressed, so as to close the passage or leave it free. 237. The SALIVARY GLANDS are six in number; three on each side of the jaw. They are called the _pa-rot´id_, the _sub-max´il-la-ry_ and the _sub-lin´gual_. [Illustration: Fig. 58. A view of the salivary glands in their proper situations. 1, The parotid gland. 2, Its duct. 3, The submaxillary gland. 4, Its duct. 5, The sublingual gland, brought to view by the removal of a section of the lower jaw.] 238. The PAROTID GLAND, the largest, is situated in front of the external ear, and behind the angle of the jaw. A duct (Steno's) from this gland opens into the mouth, opposite the second molar tooth of the upper jaw. -=-=-=-=-=-=-=-=-=-=-=-= 237. How many glands about the mouth? Give their names. What does fig. 58 represent? 238. Describe the parotid gland. -=-=-=-=-=-=-=-=-=-=-=-= 239. The SUBMAXILLARY GLAND is situated within the lower jaw, anterior to its angle. Its excretory duct (Wharton's) opens into the mouth by the side of the _fræ´num lin´guæ_, (bridle of the tongue.) 240. The _SUBLINGUAL GLAND_ is elongated and flattened, and situated beneath the mucous membrane of the floor of the mouth, on each side of the frænum linguæ. It has seven or eight small ducts, which open into the mouth by the side of the bridle of the tongue. _Observation._ In the "mumps," the parotid gland is diseased. The swelling under the tongue called the "frog" is a disease of the sublingual gland. [Illustration: Fig. 59. A side view of the face, oesophagus, and trachea. 1, The trachea (wind pipe.) 2, The larynx. 3, The oesophagus. 4, 4, 4, The muscles of the upper portion of the oesophagus forming the pharynx. 5, The muscle of the cheek. 6, The muscle that surrounds, the mouth. 7, The muscle that forms the floor of the mouth.] -=-=-=-=-=-=-=-=-=-=-=-= 239. The submaxillary. 240. The sublingual. What observation respecting these glands? What does fig. 59 represent? -=-=-=-=-=-=-=-=-=-=-=-= 241. The PHARYNX is a membranous sac, situated upon the upper portion of the spinal column. It extends from the base of the skull to the top of the _tra´che-a_, (windpipe,) and is continuous with the oesophagus. From the pharynx are four passages; one opens upward and forward to the nose, the second leads forward to the mouth, the third downward to the trachea and lungs, the fourth downward and backward to the stomach. 242. The OESOPHAGUS is a large membranous tube that extends behind the trachea, the heart, and lungs, pierces the diaphragm, and terminates in the stomach. It is composed of two membranes--an internal, or mucous, and a muscular coat. The latter is composed of two sets of fibres; one extends lengthwise, the other is arranged in circular bands. 243. The STOMACH is situated in the left side of the abdomen, immediately below and in contact with the diaphragm. It has two openings; one connected with the oesophagus, called the _car´di-ac_ orifice; the other connected with the upper portion of the small intestine, called the _py-lor´ic_ orifice. It is composed of three coats, or membranes. The exterior or serous coat is very tough and strong, and invests every part of this important organ. The middle, or muscular coat is composed of two layers of muscular fibres, one set of which is arranged longitudinally, the other circularly. The interior coat is called the mucous, and is arranged in _ru´gæ_, (folds.) The stomach is provided with a multitude of small glands, in which is secreted the gastric fluid. _Illustration._ The three coats of the stomach anatomically resemble tripe, which is a preparation of the largest stomach of the cow or ox. The outer coat is smooth and highly polished. The middle coat is composed of minute threads, which are arranged in two layers. The fibres of these layers cross each other. The inner coat is soft, and presents many folds, usually named "the honey-comb." -=-=-=-=-=-=-=-=-=-=-=-= 241. Describe the pharynx and the passages leading from it. 242. Give the structure of the oesophagus. 243. Where is the stomach situated? How many coats has it? Describe them. What article prepared for food does the stomach resemble? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 60. The inner surface of the stomach and duodenum. 1, The lower portion of the oesophagus. 2, The opening through which the food is passed into the stomach. 8, The stomach. 9, The opening through which the food passes out of the stomach into the duodenum, or upper portion of the small intestine. 10, 11, 14, The duodenum 12, 13, Ducts through which the bile and pancreatic fluid pass into it. _a_, _b_, _c_, The three coats of the stomach.] 244. The INTESTINES, or alimentary canal, are divided into two parts--the _small_ and _large_. The small intestine is about twenty-five feet in length, and is divided into three portions, namely, the _Du-o-de´num_, the _Je-ju´num_, and the _Il´e-um_. The large intestine is about five feet in length, and is divided into three parts, namely, the _Cæ´cum_, the _Co´lon_, and the _Rec´tum_. (Appendix D.) 245. The DUODENUM is somewhat larger than the rest of the small intestine, and has received its name from being in length about the breadth of twelve fingers. It commences at the pylorus, and ascends obliquely backward to the under surface of the liver. It then descends perpendicularly in front of the right kidney, and passes transversely across the lower portion of the spinal column, behind the colon, and terminates in the jejunum. The ducts from the liver and pancreas open into the perpendicular portion, about six inches from the stomach. -=-=-=-=-=-=-=-=-=-=-=-= 244. Explain fig. 60. What is the length of the small intestine, and how is it divided? What is the length of the large intestine? Give its divisions. 245. Describe the duodenum. -=-=-=-=-=-=-=-=-=-=-=-= 246. The JEJUNUM is continuous with the duodenum. It is thicker than the rest of the small intestine, and has a pinkish tinge. 247. The ILEUM is smaller, and thinner in texture, and somewhat paler, than the jejunum. There is no mark to distinguish the termination of the one or the commencement of the other. The ileum terminates near the right haunch-bone, by a valvular opening into the colon at an obtuse angle. This arrangement prevents the passing of substances from the colon into the ileum. The jejunum and ileum are surrounded above and at the sides by the colon. 248. The small intestine, like the stomach, has three coats. The inner, or mucous coat is thrown into folds, or valves. In consequence of this valvular arrangement, the mucous membrane is more extensive than the other tissues, and gives a greater extent of surface with which the aliment comes in contact. There are imbedded under this membrane an immense number of minute glands, and it has a great number of piles, like those upon velvet. For this reason, this membrane is sometimes called the _vil´lous_ coat. 249. The C�CUM is the blind pouch, or cul-de-sac, at the commencement of the large intestine. Attached to its extremity is the _ap-pend´ix verm-i-form´is_, (a long, worm-shaped tube.) It is from one to six inches in length, and of the size of a goose-quill. -=-=-=-=-=-=-=-=-=-=-=-= What important ducts open into it? 246. Describe the jejunum. 247. The ileum. 248. What is said of the coats of the intestines? Why is the mucous membrane sometimes called the villous coat? 249. Describe the cæcum. -=-=-=-=-=-=-=-=-=-=-=-= 250. The COLON is divided into three parts--the _ascending_, _transverse_, and _descending_. The ascending colon passes upward from the right haunch-bone to the under surface of the liver. It then bends inward, and crosses the upper part of the abdomen, below the liver and stomach, to the left side under the name of the transverse colon. At the left side, it turns, and descends to the left haunch-bone, and is called the descending colon. Here it makes a peculiar curve upon itself, which is called the _sig´moid flex´ure_. [Illustration: Fig. 61. 1, 1, The duodenum. 2, 2, The small intestine. 3, The junction of the small intestine with the colon. 4, The appendix vermiformis. 5, The cæcum. 6, The ascending colon. 7, The transverse colon. 8, The descending colon. 9, The sigmoid flexure of the colon. 10, The rectum.] -=-=-=-=-=-=-=-=-=-=-=-= 250. Describe the course of the divisions of the colon. Explain fig. 61. -=-=-=-=-=-=-=-=-=-=-=-= 251. The RECTUM is the termination of the large intestine. The large intestine has three coats, like the stomach and small intestine. The longitudinal fibres of the muscular coat are collected into three bands. These bands are nearly one half shorter than the intestine, and give it a sacculated appearance, which is characteristic of the cæcum and colon. 252. The LACTEALS are minute vessels, which commence in the villi, upon the mucous surface of the small intestine. From the intestine they pass between the membranes of the _mes´en-ter-y_ to small glands, which they enter. The first range of glands collects many small vessels, and transmits a few larger branches to a second range of glands; and, finally, after passing through several successive ranges of these glandular bodies, the lacteals, diminished in number and increased in size, proceed to the enlarged portion of the thoracic duct, into which they open. They are most numerous in the upper portion of the small intestine. 253. The THORACIC DUCT commences in the abdomen, by a considerable dilatation, which is situated in front of the lower portion of the spinal column. From this point, it passes through the diaphragm, and ascends to the lower part of the neck. In its ascent, it lies anterior to the spine, and by the side of the aorta and oesophagus. At the lower part of the neck, it makes a sudden turn downward and forward, and terminates by opening into a large vein which passes to the heart. The thoracic duct is equal in diameter to a goose-quill, and, at its termination, is provided with a pair of semilunar valves, which prevent the admission of venous blood into its cylinder. -=-=-=-=-=-=-=-=-=-=-=-= 251. What is said of the arrangement of the fibres of the muscular coat of the large intestine? 252. What are the lacteals? Give their course from the mucous coat of the intestine to the thoracic duct. 253. Describe the course of the thoracic duct. How is the venous blood prevented from passing into this duct? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 62. A portion of the small intestine, lacteal vessels, mesenteric glands, and thoracic duct. 1, The intestine. 2, 3, 4, Mesenteric glands, through which the lacteals pass to the thoracic duct. 5, 6, The thoracic duct. 7, The point in the neck where it turns down to enter the vein at 8. 9, 10, The aorta. 11, 12, Vessels of the neck. 13, 14, 15, The large veins that convey the blood and chyle to the heart. 16, 17, The spinal column. 18, The diaphragm, (midriff.)] -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 62. What is said respecting the mesenteric glands? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ The mesenteric glands, which are situated between two layers of serous membrane (mesentery) that connects the small intestine with the spinal column, occasionally become diseased in childhood, and prevent the chyle from passing to the thoracic duct. Children thus affected have a voracious appetite, and at the same time are becoming more and more emaciated. The disease is called mesenteric consumption. 254. The LIVER, a gland appended to the alimentary canal, is the largest organ in the system, and weighs about four pounds. It is situated in the right side, below the diaphragm, and is composed of several lobes. Its upper surface is convex; its under, concave. This organ is retained in its place by several ligaments. It performs the double office of separating impurities from the venous blood, and of secreting a fluid (bile) necessary to chylification. On the under surface of the liver is a membranous sac, called the _gall-cyst_, which is generally considered as a reservoir for the bile. [Illustration: Fig. 63. The under surface of the liver. 1, The right lobe. 2, The left. 3, 4, Smaller lobes. 10, The gall-bladder, or cyst, lodged in its depression. 17, The notch on the posterior border, for the spinal column.] _Observation._ A good idea of the liver and intestines can be obtained by examining these parts of a pig. In this animal, the sacs, or pouches, of the large intestine are well defined. 255. The PANCREAS is a long, flattened gland, analogous to the salivary glands. It is about six inches in length, weighs three or four ounces, and is situated transversely across the posterior wall of the abdomen, behind the stomach. A duct from this organ opens into the duodenum. -=-=-=-=-=-=-=-=-=-=-=-= 254. Describe the liver. 255. What is said of the pancreas? -=-=-=-=-=-=-=-=-=-=-=-= 256. The SPLEEN, (milt,) so called because the ancients supposed it to be the seat of melancholy, is an oblong, flattened organ, situated in the left side, in contact with the diaphragm, stomach, and the pancreas. It is of a dark, bluish color, and is abundantly supplied with blood, but has no duct which serves as an outlet for any secretion. Its use is not well determined. [Illustration: Fig. 64. The pancreas with its duct, through which the pancreatic secretion passes into the duodenum.] 257. The OMENTUM (caul) consists of four layers of the serous membrane, which descends from the stomach and transverse colon. A quantity of adipose matter is deposited around its vessels, which ramify through its structure. Its function is twofold in the animal economy. 1st. It protects the intestines from cold. 2d. It facilitates the movements of the intestines upon each other during their vermicular, or worm-like action. 258. Every part of the digestive apparatus is supplied with arteries, veins, lymphatics, and nervous filaments, from the ganglionic system of nerves. -=-=-=-=-=-=-=-=-=-=-=-= 256. Why is the spleen so called? What is peculiar to this organ? 257. Of what is the omentum composed? What is its use? 258. With what is every part of the digestive apparatus supplied? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XIV. PHYSIOLOGY OF THE DIGESTIVE ORGANS. 259. Substances received into the stomach as food, must necessarily undergo many changes before they are fitted to form part of the animal body. The solid portions are reduced to a fluid state, and those parts that will nourish the body are separated from the waste material. 260. The first preparation of food for admission into the system, consists in its proper mastication. The lips in front, the cheeks upon the side, the soft palate, by closing down upon the base of the tongue, retain the food in the mouth, while it is subjected to the; process of _mas-ti-ca´tion_, (chewing.) The tongue rolls the mass around, and keeps it between the teeth, while they divide the food to a fineness suitable for the stomach. 261. While the food is in process of mastication, there is incorporated with it a considerable amount of _sa-li´va_, (spittle.) This fluid is furnished by the salivary glands, situated in the vicinity of the mouth. The saliva moistens and softens the food, so that, when carried into the pharynx. it is passed, with ease, through the oesophagus into the stomach. 262. When the food has been properly masticated, (and in rapid eaters when it is not,) the soft palate is raised from the base of the tongue backward, so as to close the posterior opening through the nostrils. By a movement of the muscles of the tongue, cheeks, and floor of the mouth, simultaneous with that of the soft palate, the food is pressed into the upper part of the pharynx. -=-=-=-=-=-=-=-=-=-=-=-= 259-272. _Give the physiology of the digestive organs._ 259. What is necessary before food can nourish the body? 260. Describe how mastication is performed. 261. Of what use is the saliva in the process of mastication? 262. How is the food pressed into the pharynx? -=-=-=-=-=-=-=-=-=-=-=-= 263. When in the pharynx, the food and drink are prevented from passing into the trachea by a simple valve-like arrangement, called the _ep-i-glot´tis_. The ordinary position of this little organ is perpendicular, so as not to obstruct the passage of air into the lungs; but in the act of swallowing, it is brought directly over the opening of the trachea, called the _glot´tis_. The food, being forced backward, passes rapidly over the epiglottis into the oesophagus, where the circular band of muscular fibres above, contracts and forces the food to the next lower band. Each band relaxes and contracts successively, and thus presses the alimentary ball downward and onward to the stomach.[8] [8] The process of deglutition may be comprehended by analyzing the operation of swallowing food or saliva. _Observation._ If air is inhaled when the food or drink is passing over the glottis, some portions of it may be carried into the larynx or trachea. This produces violent spasmodic coughing, and most generally occurs when an attempt is made to speak while masticating food; therefore, never talk when the mouth contains food. -=-=-=-=-=-=-=-=-=-=-=-= 263. When the food is in the pharynx, how is it prevented from passing into the trachea, or windpipe? Describe how it is passed into the stomach? Give the observation. 264. Describe how the food in the stomach is converted into chyme. -=-=-=-=-=-=-=-=-=-=-=-= 264. When the food reaches the stomach, the gastric glands are excited to action, and they secrete a powerful solvent, called gastric juice. The presence of food in the stomach also increases a contractile action of the muscular coat, by which the position of the food is changed from one part of this cavity to another. Thus the aliment is brought in contact with the mucous membrane, and each portion of it becomes saturated with gastric juice, by which it is softened, or dissolved into a pulpy homogeneous mass, of a creamy consistence, called _Chyme_. The food is not all converted into chyme at the same time; but as fast as it is changed, it passes through the pyloric orifice into the duodenum. _Observation._ The gastric juice has the property of coagulating liquid albuminous matter when mixed with it. It is this property of rennet, which is an infusion of the fourth stomach of the calf, by which milk is coagulated, or formed into "curd." 265. The CHYME is conveyed through the pyloric orifice of the stomach into the duodenum. The chyme not only excites an action in the duodenum, but also in the liver and pancreas. _Mucus_ is then secreted by the duodenum, _bile_ by the liver, and _pancreatic fluid_ by the pancreas. The bile and pancreatic fluid are conveyed into the duodenum, and mixed with the chyme. By the action of these different fluids, the chyme is converted into a fluid of a whitish color, called _Chyle_, and into residuum. _Observation._ The bile has no agency in the change through which the food passes in the stomach. In a healthy condition of this organ, no bile is found in it. The common belief, that the stomach has a redundancy of this secretion, is erroneous. If bile is ejected in vomiting, it merely shows, not only that the action of the stomach is inverted, but also that of the duodenum. A powerful emetic will, in this way, generally bring this fluid from the most healthy stomach. A knowledge of this fact might save many a stomach from the evils of emetics, administered on false impressions of their necessity, and continued from the corroboration of these by the appearance of bile, till derangement, and perhaps permanent disease, are the consequences. 266. The CHYLE and residual matter are moved over the mucous surface of the small intestine, by the action of its muscular coat. As the chyle is carried along the tract of the intestine, it comes in contact with the villi, where the lacteal vessels commence. These imbibe, or take up, the chyle, and transfer it through the mesenteric glands into the thoracic duct, through which it is conveyed into a large vein at the lower part of the neck. In this vein the chyle is mixed with the venous fluid. The residual matter is conveyed into the large intestine, through which it is carried and excreted from the system. (Appendix E.) -=-=-=-=-=-=-=-=-=-=-=-= What peculiar property has gastric juice? 265. Where and how is chyme converted into chyle? What is said in regard to the bile? 266. What becomes of the chyle? Of the residuum? -=-=-=-=-=-=-=-=-=-=-=-= 267. In the process of digestion, the food is subjected to five different changes. 1st. The chewing and admixture of the saliva with the food; this process is called _mastication_. 268. 2d. The change through which the food passes in the stomach by its muscular contraction, and the secretion from the gastric glands; this is called _chymification_. 269. 3d. The conversion of the homogeneous chyme, by the agency of the bile and pancreatic secretions, into a fluid of milk-like appearance; this is _chylification_. 270. 4th. The absorption of the chyle by the lacteals, and its transfer through them and the thoracic duct, into the subclavian vein at the lower part of the neck.[9] [9] The chyle is changed by the lacteals and mesenteric glands, but the nature of this change is not, as yet, well defined or understood. 271. 5th. The separation and excretion of the residuum. 272. Perfection of the second process of digestion requires thorough and slow mastication. The formation of proper chyle demands appropriate mastication and chymification; while a healthy action of the lacteals requires that all the anterior stages of the digestive process be as perfect as possible. (Appendix F.) -=-=-=-=-=-=-=-=-=-=-=-= 267. Recapitulate the five changes in the digestive process. -=-=-=-=-=-=-=-=-=-=-=-= _Note._ Let the pupil review the anatomy and physiology of the digestive organs from figs. 62 and 65, or from anatomical outline plate No. 5. [Illustration: Fig. 65. An ideal view of the organs of digestion, opened nearly the whole length. 1, The upper jaw. 2, The lower jaw. 3, The tongue. 4, The roof of the mouth. 5, The oesophagus. 6, The trachea. 7, The parotid gland. 8, The sublingual gland. 9, The stomach. 10, 10, The liver. 11, The gall-cyst. 12, The duct that conveys the bile to the duodenum, (13, 13.) 14, The pancreas. 15, 15, 15, 15, The small intestine. 16, The opening of the small intestine into the large intestine. 17, 18, 19, 20, The large intestine. 21, The spleen. 22, The upper part of the spinal column.] CHAPTER XV. HYGIENE OF THE DIGESTIVE ORGANS. 273. It is a law of the system, that each organ is excited to healthy and efficient action, when influenced by its appropriate stimulus. Accordingly, nutrient food, that is adapted to the wants of the system, imparts a healthy stimulation to the salivary glands during the process of mastication. The food that is well masticated, and has blended with it a proper amount of saliva, will induce a healthy action in the stomach. Well-prepared chyme is the natural stimulus of the duodenum, liver, and pancreas; pure chyle is the appropriate excitant of the lacteal vessels. 274. The perfection of the digestive process, as well as the health of the general system, requires the observance of certain conditions. These will be considered under four heads:--1st. The _Quantity_ of food that should be taken. 2d. Its _Quality_. 3d. The _Manner_ in which it should be taken. 4th. The _Condition_ of the system when food is taken. 275. The QUANTITY of food necessary for the system varies. Age, occupation, temperament, temperature, habits, amount of clothing, health and disease are among the circumstances which produce the variation. -=-=-=-=-=-=-=-=-=-=-=-= 273-330. _Give the hygiene of the digestive organs._ 273. Give a law of the system. What is the appropriate stimulus of the salivary glands during mastication? Of the stomach? Of the duodenum? Of the lacteal vessels? 274. What does the perfection of the digestive organs require? 275. What exert an influence on the quantity of food necessary for the system? -=-=-=-=-=-=-=-=-=-=-=-= 276. _The child and youth require food to promote the growth of the different parts of the body._ The more rapid the growth of the child, the greater the demand for food. This accounts for the keen appetite and vigorous digestion in childhood. When the youth has attained his full growth, this necessity for nutriment ceases; after this period of life, if the same amount of food is taken, and there is no increase of labor or exertion, the digestive apparatus will become diseased, and the vigor of the whole system diminished. _Observation._ When the body has become emaciated from want of nutriment, either from famine or disease, there is an increased demand for food. This may be gratified with impunity until the individual has regained the usual size, but repletion should be avoided. 277. _Food is required to repair the waste, or loss of substance that attends action._ In every department of nature, waste, or loss of substance, attends and follows action. When an individual increases his exercise,--changes from light to severe labor,--or the inactive and sedentary undertake journeys for pleasure, the fluids of the system circulate with increased energy. The old and exhausted particles of matter are more rapidly removed through the action of the vessels of the skin, lungs, kidneys, and other organs, and their places are filled with new atoms, deposited by the small blood-vessels. 278. As the chyle supplies the blood with the newly vitalized particles of matter, there is, consequently, an increased demand for food. This want of the system induces, in general, a sensation of hunger or appetite, which may be regarded as an indication of the general state of the body. The sympathy that exists throughout the system accords to the stomach the power of making known this state to the nervous system, and, if the functions of this faithful monitor have not been impaired by disease, abuse, or habit, the call is imperious, and should be regarded. -=-=-=-=-=-=-=-=-=-=-=-= 276. At what age is the appetite keen and the digestion vigorous? Why? What is said in regard to the quantity of food when the youth has attained his growth? What exception, as given in the observation? 277. Give another demand for food. What effect has increased exercise upon the system? 278. How are the new particles of matter supplied? What does this induce? -=-=-=-=-=-=-=-=-=-=-=-= 279. _When exercise or labor is lessened, the quantity of food should be diminished._ When a person who has been accustomed to active exercise, or even hard manual labor, suddenly changes to an employment that demands less activity, the waste attendant on action will be diminished in a corresponding degree; hence the quantity of food should be lessened in nearly the same proportion as the amount of exercise is diminished. If this principle be disregarded, the tone of the digestive organs will be impaired, and the health of the system enfeebled. 280. This remark is applicable to those students who have left laborious employments to attend school. Although the health is firm, and the appetite keen from habit, yet every pupil should practise some self-denial, and not eat as much as the appetite craves, the first week of the session. After some days, the real wants of the system will generally be manifested by a corresponding sensation of hunger. _Observation._ It is a common observation that in academies and colleges, the older students from the country, who have been accustomed to hard manual labor, suffer more frequently from defective digestion and impaired health than the younger and feebler students from the larger towns and cities. 281. _Food is essential in maintaining a proper temperature of the system._ The heat of the system, at least in part, is produced in the minute vessels of the several organs, by the union of oxygen with carbon and hydrogen, which the food and drink contain. The amount of heat generated, is greatest when it is most rapidly removed from the system, which occurs in cold weather. This is the cause of the system requiring more food in winter than summer. -=-=-=-=-=-=-=-=-=-=-=-= 279. Why should the quantity of food be diminished when the exercise is lessened? What effect if this principle be disregarded? 280. To what class is this remark applicable? What is often observed among students in academies and colleges? 281. State another demand for food. What is one source of heat in the body? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Persons that do not have food sufficient for the natural wants of the system, require more clothing than those who are well fed. 282. The last-mentioned principle plainly indicates the propriety and necessity of lessening the quantity of food as the warm season approaches. Were this practised, the tone of the stomach and the vigor of the system would continue unimpaired, the "season complaints" would be avoided, and the "strengthening bitters" would not be sought to create an appetite. _Observation._ Stable-keepers and herdsmen are aware of the fact, that as the warm season commences, then animals require less food. Instinct teaches these animals more truly, in this particular, than man allows reason to guide him. 283. _The quantity of food should have reference to the present condition of the digestive organs._ If they are weakened or diseased, so that but a small quantity of food can be properly digested or changed, that amount only should be taken. Food does not invigorate the system, except it is changed, as has been described in previous paragraphs. _Observation._ When taking care of a sick child, the anxiety of the mother and the sufferings of the child may induce her to give food when it would be highly injurious. The attending physician is the only proper person to direct what quantity should be given. -=-=-=-=-=-=-=-=-=-=-=-= Why do we eat more in the winter than in the summer? What practical observation is given? 282. Why should the quantity of food be lessened as warm weather commences? What would be avoided if this principle were obeyed? 283. Why should the present condition of the digestive organs be regarded in reference to the quantity of food? Mention an instance in which it would be injudicious to give food. -=-=-=-=-=-=-=-=-=-=-=-= 284. _The quantity of food is modified, in some degree, by habit._ A healthy person, whose exercise is in pure air, may be accustomed to take more food than is necessary. The useless excess is removed from the system by the waste outlets, as the skin, lungs, liver, kidneys, &c. In such cases, if food is not taken in the usual quantity, there will be a feeling of emptiness, if not of hunger, from the want of the usual distention of the stomach. This condition of the digestive organs may be the result of disease, but it is more frequently produced by inordinate daily indulgence in eating, amounting almost to gluttony. 285. _Large quantities of food oppress the stomach, and cause general languor of the whole body._ This is produced by the extra demands made on the system for an increased supply of blood and nervous fluid to enable the stomach to free itself of its burden. Thus, when we intend to make any extraordinary effort, mental or physical, at least for one meal, we should eat less food than usual, rather than a greater quantity. 286. _No more food should be eaten than is barely sufficient to satisfy the appetite._ Nor should appetite be confounded with taste. The one is a natural desire for food to supply the wants of the system; the other is an artificial desire merely to gratify the palate. 287. Although many things may aid us in determining the quantity of food proper for an individual, yet there is no certain guide in all cases. It is maintained by some, that the sensation of hunger or appetite is always an indication of the want of food, while the absence of this peculiar sensation is regarded as conclusive evidence that aliment is not demanded. This assertion is not correct, as an appetite may be created for food by condiments and gormandizing, which is as artificial and as morbid as that which craves tobacco or ardent spirits. On the other hand, a structural or functional disease of the brain may prevent that organ from taking cognizance of the sensations of the stomach, when the system actually requires nourishment. Observation shows, that disease, habit, the state of the mind, and other circumstances, exert an influence on the appetite. -=-=-=-=-=-=-=-=-=-=-=-= 284. Show the effect of habit upon the quantity of food that is eaten. What is said in regard to inordinate eating? 285. What is the effect of eating large quantities of food? What suggestion when an extraordinary effort, either mental or physical, is to be made? 286. How much food should generally be eaten? 287. What is the assertion of some persons relative to the quantity of food necessary for the system? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Dr. Beaumont noticed, in the experiments upon Alexis St. Martin, that after a certain amount of food was converted into chyme, the gastric juice ceased to ooze from the coats of the stomach. Consequently, it has been inferred by some writers on physiology, that the glands which supply the gastric fluid, by a species of instinctive intelligence, would only secrete enough fluid to convert into chyme the aliment needed to supply the real wants of the system. What are the reasons for this inference? There is no evidence that the gastric glands possess instinctive intelligence, and can there be a reason adduced, why they may not be stimulated to extra functional action as well as other organs, and why they may not also be influenced by habit? 288. While all agree that the remote or predisposing cause of hunger is, usually, a demand of the system for nutrient material, the proximate or immediate cause of the sensation of hunger is not clearly understood. Some physiologists suppose that it is produced by an engorged condition of the glands of the stomach which supply the gastric juice; while others maintain that it depends on a peculiar condition of the nervous system. 289. The QUALITY of the food best adapted to the wants of the system is modified by many circumstances. There are many varieties of food, and these are much modified by the different methods of preparation. The same kind of food is not equally well adapted to different individuals, or to the same individual in all conditions; as vocation, health, exposure, habits of life, season, climate, &c., influence the condition of the system. -=-=-=-=-=-=-=-=-=-=-=-= What does observation show? 288. What is said of the causes of hunger? 289. Why is not the same kind of food adapted to different individuals? -=-=-=-=-=-=-=-=-=-=-=-= 290. All articles of food may be considered in two relations: 1st, As nutritive. 2d, As digestible. Substances are nutritious in proportion to their capacity to yield the elements of chyle, of which carbon, oxygen, hydrogen, and nitrogen are the most essential; they are digestible in proportion to the facility with which they are acted upon by the gastric juice. These properties should not be confounded in the various articles used for food. 291. As a "living body has no power of forming elements, or of converting one elementary substance into another, it therefore follows that the elements of which the body of an animal is composed must be in the food." (Chap. III.) Of the essential constituents of the human body, carbon, hydrogen, oxygen, and nitrogen are the most important, because they compose the principal part of the animal body; while the other elements are found in very small proportions, and many of them only in a few organs of the system. (Appendix G.) _Observation._ Nitrogen renders food more stimulating, particularly if combined with a large quantity of carbon, as beef. Those articles that contain the greatest amount of the constituent elements of the system are most nutritious. As milk and eggs contain all the essential elements of the human system, so they are adapted to almost universal use, and are highly nutritious. -=-=-=-=-=-=-=-=-=-=-=-= 290. In what proportion are substances nutritious? Digestible? Why does beef stimulate the system? What is said of milk and eggs? -=-=-=-=-=-=-=-=-=-=-=-= 292. The following table, by Pereira, in his treatise on Food and Diet may aid the student in approximating to correct conclusions of the quantity of nutriment in different kinds of food, and its adaptation to the wants of the system. TABLE, SHOWING THE AVERAGE QUANTITY OF DRY, OR SOLID MATTER, CARBON, NITROGEN, AND MOISTURE, IN DIFFERENT ARTICLES OF DIET. -------------------+---------+---------+-----------+------------ One hundred Parts. | Dry | Carbon. | Nitrogen. | Water | Matter. | | | -------------------+---------+---------+-----------+------------ Arrowroot, | 81.8 | 36.4 | | 18.2 Beans, | 85.89 | 38.24 | | 14.11 Beef, fresh, | 25 | 12.957 | 3.752 | 75 Bread, rye, | 67.79 | 30.674 | | 32.21 Butter, | 100 | 65.6 | | Cabbage, | 7.7 | | 0.28 | 92.3 Carrot, | 12.4 | | 0.30 | 87.6 Cherries, | 25.15 | | | 74.85 Chickens, | 22.7 | | | 77.3 Codfish, | 20 | | | 80 Cucumbers, | 2.86 | | | 97.14 Eggs, whites, | 20 | | | 80 ----, yolk, | 46.23 | | | 53.77 Lard, hog's, | 100 | 79.098 | | Milk, cow's, | 12.98 | | | 87.02 Oats, | 79.2 | 40.154 | 1.742 | 20.8 Oatmeal, | 93.4 | | | 6.6 Olive-oil, | 100 | 77.50 | | Oysters, | 12.6 | | | 87.4 Peaches, | 19.76 | | | 80.24 Pears, | 16.12 | | | 83.88 Peas, | 84 | 35.743 | | 16 Plums, greengage, | 28.90 | | | 71.10 Potatoes, | 24.1 | 10.604 | 0.3615 | 75.9 Rye, | 83.4 | 38.530 | 1.417 | 16.6 Suet, mutton, | 100 | 78.996 | | Starch, potato, | 82 | 36.44 | | 18 ----, wheat, | 85.2 | 37.5 | | 14.8 Sugar, maple, | | 42.1 | | ----, refined, | | 42.5 | | ----, brown, | | 40.88 | | Turnips, | 7.5 | 3.2175 | 0.1275 | 92.5 Veal, roasted, | | 52.52 | 14.70 | Wheat, | 85.5 | 39.415 | 1.966 | 14.5 -------------------+---------+---------+-----------+------------ _Note._ Let the pupil mention those articles of food that are most nutritious, from a review of this table, and the last four paragraphs. 293. Those articles that do not contain the essential elements of the system should not be used as exclusive articles of diet. This principle has been, and may be illustrated by experiment. Feed a dog with pure sugar, or olive-oil, (articles that contain no nitrogen,) for several weeks, and the evil effects of non-nitrogenous nutriment will be manifested. At first, the dog will take his food with avidity, and seem to thrive upon it; soon this desire for food will diminish, his body emaciate, his eye become ulcerated, and in a few weeks he will die; but mix bran or sawdust with the sugar or oil, and the health and vigor of the animal will be maintained for months. A similar phenomenon will be manifested, if grain only be given to a horse, without hay, straw, or material of like character. (Appendix H.) 294. Some articles of food contain the elements of chyle in great abundance, yet afford but little nutriment, because they are difficult of digestion; while other articles contain but a small quantity of these elements, and afford more nourishment, because they are more easily affected by the digestive process. -=-=-=-=-=-=-=-=-=-=-=-= 293. How has the effect of non-nitrogenous nutriment been illustrated? 294. Why do some articles of food that contain the elements of chyle afford but little nutriment? Why do articles that contain a small quantity of these elements afford more nourishment? 295. How was the time required for digesting different articles of food ascertained? -=-=-=-=-=-=-=-=-=-=-=-= 295. The following table exhibits the general results of experiments made on Alexis St. Martin, by Dr. Beaumont, when he endeavored to ascertain the time required for the digestion of different articles of food.[10] The stomach of St. Martin was ruptured by the bursting of a gun. When he recovered from the effects of the accident under the surgical care of Dr. Beaumont, the stomach became adherent to the side, with an external aperture. Nature had formed a kind of valve, which closed the aperture from the interior, and thus prevented the contents of the stomach from escaping; but on pushing it aside, the process of digestion could be seen. Through this opening, the appearance of the coats of the stomach and food, at different stages of digestion, were examined. [10] The time required for the digestion of the different articles of food might vary in other persons; and would probably vary in the same individual at different periods, as the employment, health, season, &c., exert a modifying influence. TABLE, SHOWING THE MEAN TIME OF DIGESTION OF THE DIFFERENT ARTICLES OF DIET. -----------------------------+--------------+-------- Articles. | Preparation. | Time | | h. m. -----------------------------+--------------+-------- Apples, sour, hard, | Raw, | 2 50 Apples, sour, mellow, | Raw, | 2 Apples, sweet, do., | Raw, | 1 30 Bass, striped, fresh, | Broiled, | 3 Beans, pod, | Boiled, | 2 30 Beef, fresh, lean, rare, | Roasted, | 3 Beef, fresh, lean, dry, | Roasted, | 3 30 Beef steak, | Broiled, | 3 Beef, with salt only, | Boiled, | 3 36 Beef, with mustard, | Boiled, | 3 10 Beef, fresh, lean, | Fried, | 4 Beef, old, hard, salted, | Boiled, | 4 15 Beets, | Boiled, | 3 45 Bread, wheat, fresh, | Baked, | 3 30 Bread, corn, | Baked, | 3 15 Butter, | Melted, | 3 30 Cabbage head, | Raw, | 2 30 Cabbage, with vinegar, | Raw, | 2 Cabbage, | Boiled, | 4 30 Cake, sponge, | Baked, | 2 30 Carrot, orange, | Boiled, | 3 15 Catfish, | Fried, | 3 30 Cheese, old, strong, | Raw, | 3 30 Chicken, full-grown, | Fricas'd, | 2 45 Codfish, cured, dry, | Boiled, | 2 Corn, green, & beans, | Boiled, | 3 45 Corn bread, | Baked, | 3 15 Corn cake, | Baked, | 3 Custard, | Baked, | 2 45 Dumpling, apple, | Boiled, | 3 Ducks, domesticated, | Roasted, | 4 Ducks, wild, | Roasted, | 4 30 Eggs, fresh, | Boiled hard, | 3 30 Eggs, fresh, | Boiled soft, | 3 Eggs, fresh, | Fried, | 3 30 Eggs, fresh, | Raw, | 2 Flounder, fresh, | Fried, | 3 30 Fowl, domestic, | Boiled, | 4 Fowl, domestic, | Roasted, | 4 Goose, | Roasted, | 2 30 Lamb, fresh, | Broiled, | 2 30 Liver, beef's, fresh, | Broiled, | 2 Meat hashed with vegetables, | Warm'd, | 2 30 Milk, | Boiled, | 2 Milk, | Raw, | 2 15 Mutton, fresh, | Roasted, | 3 15 Mutton, fresh, | Broiled, | 3 Mutton, fresh, | Boiled, | 3 Oysters, fresh, | Raw, | 2 55 Oysters, fresh, | Roasted, | 3 15 Oysters, fresh, | Stewed, | 3 30 Parsnips, | Boiled, | 2 30 Pig, sucking, | Roasted, | 2 30 Pigs' feet, soused, | Boiled, | 1 Pork, fat and lean, | Roasted, | 5 15 Pork, recently salted, | Boiled, | 4 30 Pork, recently salted, | Fried, | 4 15 Pork, recently salted, | Broiled, | 3 15 Pork, recently salted, | Raw, | 3 Pork, steak, | Broiled, | 3 15 Potatoes, Irish, | Boiled, | 3 30 Potatoes, Irish, | Baked, | 2 30 Rice, | Boiled, | 1 Sago, | Boiled, | 1 45 Salmon, salted, | Boiled, | 4 Sausage, fresh, | Broiled, | 3 20 Soup, beef, vegetables, and | Boiled, | 4 bread, | | Soup, chicken, | Boiled, | 3 Soup, mutton, | Boiled, | 3 30 Soup, oyster, | Boiled, | 3 30 Suet, beef, fresh, | Boiled, | 5 30 Suet, mutton, | Boiled, | 4 30 Tapioca, | Boiled, | 2 Tripe, soused, | Boiled, | 1 Trout, salmon, fresh, | Boiled, | 1 30 Trout, salmon, fresh, | Fried, | 1 30 Turkey, domesticated, | Roasted, | 2 30 Turkey, | Boiled, | 2 25 Turkey, wild, | Roasted, | 2 18 Turnips, flat, | Boiled, | 3 30 Veal, fresh, | Broiled, | 4 Veal, fresh, | Fried, | 4 30 Venison steak, | Broiled, | 1 35 -----------------------------+--------------+-------- 296. In view of this table, the question may be suggested, Is that article of food most appropriate to the system which is most easily and speedily digested? To this it may be replied, that the stomach is subject to the same law as the muscles and other organs; exercise, within certain limits, strengthens it. If, therefore, we always eat those articles most easily digested, the digestive powers will be weakened; if over-worked, they will be exhausted. Hence the kind and amount of food should be adapted to the maintenance of the digestive powers, and to their gradual invigoration when debilitated. _Observation._ Food that is most easily digested is not always most appropriate to a person convalescing from disease. If the substance passes rapidly through the digestive process, it may induce a recurrence of the disease. Thus the simple preparations which are not stimulating, as water-gruel, are better for a sick person than the more digestible beef and fish. 297. The question is not well settled, whether animal or vegetable food is best adapted to nourish man. There are nations, particularly in the torrid zone, that subsist, exclusively, on vegetables; while those of the frigid zone feed on fish or animal food. In the temperate zone, among civilized nations, a mixed diet is almost universal. When we consider the organization of the human system, the form and arrangement of the teeth, the structure of the stomach and intestines, we are led to conclude, that both animal and vegetable food is requisite, and that a mixed diet is most conducive to strength, health, and long life. -=-=-=-=-=-=-=-=-=-=-=-= 296. How is the question answered, whether that article is most appropriate to the system which is most easily digested? Give observation. 297. What is said of the adaptation of animal and vegetable food to man? -=-=-=-=-=-=-=-=-=-=-=-= 298. _The food should be adapted to the distensible character of the stomach and alimentary canal._ The former will be full, if it contain only a gill; it may be so distended as to contain a quart. The same is true of the intestines. If the food is concentrated, or contains the quantity of nutriment which the system requires, in small bulk, the stomach and intestines will need the stimulation of distention and friction, which is consequent upon the introduction and transit of the innutritious material into and through the alimentary canal. If the food is deficient in innutritious matter, the tendency is, to produce an inactive and diseased condition of the digestive organs. For this reason, nutrient food should have blended with it innutritious material. Unbolted wheat bread is more healthy than hot flour cakes; ripe fruits and vegetables than rich pies, or jellies. _Observation._ 1st. The observance of this rule is of more importance to students, sedentary mechanics, and those individuals whose digestive apparatus has been enfeebled, than to those of active habits and firm health. 2d. The circumstance that different articles of food contain different proportions of waste, or innutritious matter, may be made practically subservient in the following way: If, at any particular season of the year, there is a tendency to a diarrhoea, an article that contains a small proportion of waste should be selected for food; but, if there is a tendency to an inactive or costive condition of the intestinal canal, such kinds of food should be used as contain the greatest proportion of waste, as such articles are most stimulating to the digestive organs, and, consequently, most laxative. 299. _In the selection of food, the influence of season and climate should be considered._ Food of a highly stimulating character may be used almost with impunity during the cold weather of a cold climate; but in the warm season, and in a warm climate, it would be very deleterious. Animal food, being more stimulating than vegetable, can be eaten in the winter but vegetable food should be used more freely in the spring and summer. -=-=-=-=-=-=-=-=-=-=-=-= 298. What is said of the distensible character of the stomach and alimentary canal? What is the effect of eating highly concentrated food? Why is the unbolted wheat bread more healthy than flour cakes? Give observation 1st. Observation 2d. 299. What kind of food is adapted to cold weather? To warm weather? -=-=-=-=-=-=-=-=-=-=-=-= 300. _The influence of food on the system is modified by the age of the individual._ The organs of a child are more sensitive and excitable than those of a person advanced in years. Therefore a vegetable diet would be most appropriate for a child, while stimulating animal food might be conducive to the health of a person advanced in life. _Observation._ When the digestive organs are highly impressible or diseased, it is very important to adopt a nutritious, unstimulating, vegetable diet, as soon as the warm season commences. 301. _Habit is another strong modifying influence._ If a person has been accustomed to an animal or vegetable diet, and there is a sudden change from one to the other, a diseased condition of the system, particularly of the digestive apparatus, usually follows. When it is necessary to change our manner of living, it should be done gradually.[11] [11] The system is gradually developed, and all changes of food, apparel, labor, exercise, or position, should be gradual. Even a change from a bad to a good habit, on this principle, should be gradual. 302. _Some temperaments require more stimulating food than others._ As a general rule, those persons whose sensations are comparatively obtuse, and movements slow, will be benefited by animal food; while those individuals whose constitutions are highly impressible, and whose movements are quick and hurried, require a nutritious and unstimulating vegetable diet. -=-=-=-=-=-=-=-=-=-=-=-= 300. What kinds of food are appropriate to old age? Why? What kinds to childhood? Why? 301. What is the effect when there is a sudden change from a vegetable to an animal diet? How should all changes of the system be made? 302. Do different temperaments require different kinds of food? What general rule is given? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XVI. HYGIENE OF THE DIGESTIVE ORGANS, CONTINUED. 303. The MANNER in which food should be taken is of much practical importance; upon it the health of the digestive organs measurably depends. But few circumstances modify the proper manner of taking food, or should exercise any controlling influence. 304. _Food should be taken at regular periods._ The interval between meals should be regulated by the character of the food, the age, health, exercise, and habits of the individual. The digestive process is more energetic and rapid in the young, active, and vigorous, than in the aged, indolent, and feeble; consequently, food should be taken more frequently by the former than by the latter class. 305. In some young and vigorous persons, food may be digested in one hour; in other persons, it may require four hours or more. The average time, however, to digest an ordinary meal, will be from two to four hours. In all instances, the stomach will require from one to three hours to recruit its exhausted powers after the labor of digesting a meal before it will again enter upon the vigorous performance of its duties. 306. _Food should not be taken too frequently._ If food is taken before the stomach has regained its tone and energy by repose, the secretion of the gastric juice, and the contraction of the muscular fibres, will be imperfect. Again, if food is taken before the digestion of the preceding meal has been completed, the effects will be still worse, because the food partially digested becomes mixed with that last taken. Therefore the interval between each meal should be long enough for the whole quantity to be digested, and the time of repose should be sufficient to recruit the exhausted organs. The feebler the person and the more debilitated the stomach, the more important to observe the above directions. -=-=-=-=-=-=-=-=-=-=-=-= 303. Why is it important that we regard the manner of taking our food? 304. How should the intervals between meals be regulated? 305. What is the average time required to digest an ordinary meal? 306. Why should not food be taken too frequently? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ In the feeding of infants, as well as in supplying food to older children, the preceding suggestions should always be regarded. The person who has been confined by an exhausting sickness, should most scrupulously regard this rule, if he wishes to regain his strength and flesh with rapidity. As the rapidity of the digestive process is less in students and individuals who are engaged in sedentary employments, than in stirring agriculturists, the former class are more liable to take food too frequently than the latter, while its observance is of greater importance to the sedentary artisan than to the lively lad and active farmer. 307. _Food should be well masticated._ All solid aliments should be reduced to a state of comparative fineness, by the teeth, before it is swallowed; the gastric fluid of the stomach will then blend with it more readily, and act more vigorously in reducing it to chyme. The practice of swallowing solid food, slightly masticated, or "bolting" it down, tends to derange the digestive process and impair the nutrition of the system. 308. _Mastication should be moderate, not rapid._ In masticating food, the salivary glands are excited to action, and some time must elapse before they can, secrete saliva in sufficient quantities to moisten it. If the aliment is not supplied with saliva, digestion is retarded; besides, in rapid eating, more food is generally consumed than the system demands, or can be easily digested. Laborers, as well as men of leisure, should have ample time for taking their meals. Imperfect mastication is a prevailing cause of indigestion. -=-=-=-=-=-=-=-=-=-=-=-= What persons would be benefited by observing the preceding remarks? 307. Why should food be well masticated? What is the effect of "bolting down" food? 308. How should mastication be performed? Why? -=-=-=-=-=-=-=-=-=-=-=-= 309. _Food should be masticated and swallowed without drink._ As the salivary glands supply fluid to moisten the dry food, the use of tea, coffee, water, or any other fluid, is not demanded by nature's laws while taking a meal. One objection to "washing down" the food with drink is, the aliment is moistened, not with the saliva, but with the drink. This tends to induce disease, not only in the salivary organs, by leaving them in a state of comparative inactivity, but in the stomach, by the deficiency of the salivary stimulus. Another is, large quantities of fluids, used as drinks, give undue distention to the stomach, and lessen the energy of the gastric juice by its dilution, thus retarding digestion. Again, drinks taken into the stomach must be removed by absorption before the digestion of other articles is commenced. _Observation._ Were it customary not to place drinks on the table until the solid food is eaten, the evil arising from drinking too much at meals would be obviated. The horse is never known to leave his provender, nor the ox his blade of grass, to wash it down; but many persons, from habit rather than thirst, drink largely during meals. 310. The peculiar sensation in the mouth and fauces, called thirst, may not always arise from the demand for fluids to increase the _serum_ (water) of the blood, as in the desire for drink attendant on free perspiration, for then, pure water or some diluent drink is absolutely necessary; but it may be the result of fever, or local disease of the parts connected with the throat. In many instances, thirst may be allayed by chewing some hard substance, as a dry cracker. This excites a secretion from the salivary glands, which removes the disagreeable sensation. In thirst, attendant on a heated condition of the system, this practice affords relief, and is safe; while the practice of drinking large quantities of cold fluids, is unsafe, and should never be indulged. -=-=-=-=-=-=-=-=-=-=-=-= Why should all persons have ample time for eating? 309. Why are drinks not necessary while masticating food? Give the objections to "washing down" food. What observation relative to drink? 310. Does the sensation of thirst always arise from a real want of the system? -=-=-=-=-=-=-=-=-=-=-=-= 311. _Food or drink should not be taken when very hot._ When food or drink is taken hot, the vessels of the mucous membrane of the gums, mouth, and stomach are unduly stimulated for a short time; and this is followed by reaction, attended by a loss of tone, and debility of these parts. This practice is a fruitful cause of spongy gums, decayed teeth, sore mouth, and indigestion. 312. _Food or drink should not be taken very cold._ If a considerable quantity of very cold food or liquid be taken immediately into the stomach, the health will be endangered, and the tone of the system will be impaired, from the sudden abstraction of heat from the coats of the stomach, and from surrounding organs, to impart warmth to the cold food or drink. This arrests the digestive process, and the food is retained in the stomach too long, and causes oppression and irritation. Consequently, food and drink that are moderately heated are best adapted to the natural condition of the digestive apparatus. _Observation._ Food of an injurious quality, or taken in an improper manner, affects the inferior animals as well as man. The teeth of cows that are closely penned in cities, and are fed on distillery slops, or the unhealthy slops and remnants of kitchens, decay and fall out in about two years. Can the milk of such diseased animals be healthy--the proper nourishment for children? -=-=-=-=-=-=-=-=-=-=-=-= Give instances when it does and when it does not. 311. Why should not food or drink be taken hot? 312. Why should they not be taken cold? Show some of the effects of improper food upon the inferior animals. -=-=-=-=-=-=-=-=-=-=-=-= 313. The CONDITION of the system should be regarded when food is taken. This is necessary, as the present and ulterior condition of the digestive apparatus is strongly influenced by the state of the other organs of the system. 314. _Food should not be taken immediately after severe exertion, either of the body or mind._ For all organs in action require and receive more blood and nervous fluid, than when at rest. This is true of the brain, muscles, and vocal organs, when they have been actively exercised. The increased amount of fluid, both sanguineous and nervous, supplied to any organ during extra functional action, is abstracted from other parts of the system. This enfeebles and prostrates the parts that supply the blood and nervous fluid to the active organ. Again, when any organ has been in vigorous action for a few hours, some time will elapse before the increased action of the arteries and nerves abates, and a due supply of fluids is transmitted to other organs, or an equilibrium of action in the system is reëstablished. 315. Thus food should not be taken immediately after severe mental labor, protracted speaking, continued singing, or laborious manual toil; as the digestive organs will be in a state of comparative debility, and consequently unfit to digest food. From thirty to sixty minutes should elapse, after the cessation of severe employment, before food is taken. This time may be spent in cheerful amusement or social conversation. _Observation._ The practice of students and accountants going immediately from severe mental labor to their meals, is a pernicious one, and a fruitful cause of indigestion and mental debility. The custom of farmers and mechanics hurrying from their toil to the dinner-table, does much to cause dyspepsia and debility among these classes in community. -=-=-=-=-=-=-=-=-=-=-=-= 313. Should the condition of the system be regarded in taking food? 314. When should food not be taken? Why? What is the result when an organ has been in vigorous action? 315. After the cessation of severe toil, how much time should expire before eating? What is one cause of indigestion among students and accountants? -=-=-=-=-=-=-=-=-=-=-=-= 316. _Severe mental or manual toil should not be entered upon immediately after eating._ As there is an increased amount of blood and nervous fluid supplied to the stomach and alimentary canal during the digestion of food, a deficiency exists in other organs. This is evinced by a slight paleness of the skin, and a disinclination to active thought and exercise. Under such circumstances, if either the mind, vocal organs, or muscles are called into energetic action, there will be an abstraction of the necessary amount of blood and nervous fluid from the stomach, and the process of digestion will be arrested. This will not only cause disease of the digestive organs, but chyle will not be formed, to nourish the system. _Illustration._ An English gentleman fed two dogs upon similar articles of food. He permitted one to remain quiet in a dark room; the other he sent in pursuit of game. At the expiration of one hour, he had both killed. The stomach of the dog that had remained quiet was nearly empty. The food had been properly changed and carried forward into the alimentary canal. In the stomach of the dog that had used his muscles in chasing game, the aliment remained nearly unaltered. 317. The same principle may be applied to the action of the organs of man. If his mind or muscles act intensely soon after eating, the stomach will not be sufficiently stimulated by blood and nervous fluid to change the food in a suitable period. The Spanish practice of having a "siesta," or sleep after dinner, is far better than the custom of the Anglo-Saxon race, who hurry from their meals to the field, shop, or study, in order to save time, which, in too many instances, is lost by a sense of oppression and suffering which soon follows. -=-=-=-=-=-=-=-=-=-=-=-= 316. Why should not severe manual or mental exertion be made immediately after eating? State the illustration. 317. May this principle be applied to the action of the human stomach? What is said of the Spanish custom of resting after dinner? -=-=-=-=-=-=-=-=-=-=-=-= 318. In some instances of good health, the infringement of this organic law may seem to pass with impunity, but Nature, though lenient, sooner or later asserts her claims. The practice of the Spaniard may be improved by indulging, for an hour before resuming toil, in moderate exercise of the muscular system, conjoined with agreeable conversation and a hearty laugh, as this facilitates digestion, and tends to "shake the cobwebs from the brain." _Observation._ No judicious teamster drives his animals as soon as they have swallowed their food, but gives them a period for repose, so that their food may be digested, and their systems invigorated. In this way, he secures the greatest amount of labor from his team. 319. _The mind exerts an influence upon the digestive process._ This is clearly exhibited, when an individual receives intelligence of the loss of a friend or of property. He may at the time be sitting before a plentiful board, with a keen appetite; but the unexpected news destroys it, because the excited brain withholds its stimulus. This shows the propriety of avoiding absorbing topics of thought at meals, as labored discussions and matters of business; but substitute cheerful and light conversation, enlivening wit, humor, the social intercourse of family and friends; these keep the brain in action, but not in toil. Under such circumstances, the blood and nervous fluid flow freely, the work of digestion is readily commenced, and easily carried on. 320. _Indigestion arising from a prostration of the nervous system, should be treated with great care._ The food should be simple, nutritious, moderate in quantity, and taken at regular periods. Large quantities of stimulating food, frequently taken, serve to increase the nervous prostration. Those afflicted should exercise in the open air, and engage in social conversation, that the brain may be excited to a natural or healthy action, in order that it may impart to the digestive organs the necessary stimulation. -=-=-=-=-=-=-=-=-=-=-=-= Of the Anglo-Saxon race? 318. How can the Spanish custom be improved? 319. How is the influence of the mind on the digestive process exhibited? What does it show the necessity of avoiding? 320. How should indigestion arising from nervous prostration be treated? -=-=-=-=-=-=-=-=-=-=-=-= 321. _Persons should abstain from eating, at least three hours before retiring for sleep._ It is no unusual occurrence, for those persons who have eaten heartily immediately before retiring to sleep, to have unpleasant dreams, or to be aroused from their unquiet slumber by colic pains. In such instances, the brain becomes partially dormant, and does not impart to the digestive organs the requisite amount of nervous influence. The nervous stimulus being deficient, the unchanged food remains in the stomach, causing irritation of this organ. _Illustration._ A healthy farmer, who was in the habit of eating one fourth of a mince pie immediately before going to bed, became annoyed with unpleasant dreams, and, among the varied images of his fancy, he saw that of his deceased father. Becoming alarmed, he consulted a physician, who, after a patient hearing of the case, gravely advised him to eat _half_ of a mince pie, assuring him that he would then see his grandfather. 322. _When the general system and digestive organs are enfeebled, mild, unstimulating food, in small quantities, should be given._ In the instance of a shipwrecked and famished mariner, or a patient recovering from disease, but a small quantity of nourishment should be given at a time. The reason for this, is, that when the stomach is weakened from want of nourishment, it is as unfitted for a long period of action in digesting food, as the muscles are, under like circumstances, for walking. Consequently, knowledge and prudence should direct the administration of food under these circumstances. The popular adage, that "food never does harm when there is a desire for it," is untrue, and, if practically adopted, may be injurious and destructive to life. -=-=-=-=-=-=-=-=-=-=-=-= 321. What is the effect of eating immediately before retiring for sleep? How is this illustrated in the case of a healthy farmer? 322. How should the food be given when both the digestive organs and general system are debilitated? Give the reason. -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Liquids are rapidly removed from the stomach by absorption. Hence, in cases of great prostration, when it is desirable to introduce nutriment into the system, without delay, the animal and vegetable broths are a desirable and convenient form of supplying aliment. 323. _The condition of the skin exercises an important influence on the digestive apparatus._ Let free perspiration be checked, either from uncleanliness or from chills, and it will diminish the functional action of the stomach and its associated organs. This is one of the fruitful causes of the "liver and stomach complaints" among the half-clothed and filthy population of the crowded cities and villages of our country. Attention to clothing and bathing would likewise prevent many of the diseases of the alimentary canal, called "season complaints," particularly among children. 324. _Restricting the movements of the ribs and diaphragm impairs digestion._ At each full inspiration, the ribs are elevated, and the central portion of the diaphragm is depressed, from one to two inches. This depression is accompanied by a relaxation of the anterior abdominal walls. At each act of expiration, the relaxed abdominal muscles contract, the ribs are depressed, the diaphragm relaxes, and its central parts ascend. These movements of the midriff cause the elevation and depression of the stomach, liver, and other abdominal organs, which is a natural stimulus of these parts. -=-=-=-=-=-=-=-=-=-=-=-= In cases of great prostration, what is recommended? 323. How is the influence that the skin exercises on the digestive organs illustrated? 324. What effect on the digestive process has the restriction of the ribs and diaphragm? -=-=-=-=-=-=-=-=-=-=-=-= 325. It is noted of individuals who restrain the free movements of the abdominal muscles by tight dresses, that the tone and vigor of the digestive organs are diminished. The restricted waist will not admit of a full and deep inspiration and so essential is this to health, that abuse in this respect soon enfeebles and destroys the functions of the system. 326. _Pure air is necessary to give a keen appetite and vigorous digestion._ The digestive organs not only need the stimulus of blood, but they absolutely need the influence of pure blood, which cannot exist in the system, except when we breathe a pure air. From this we learn why those persons who sleep in small, ill ventilated rooms, have little or no appetite in the morning, and why the mouth and throat are so dry and disagreeable. The effect of impure blood, in diminishing the desire for food, and enfeebling the digestive organs, is well illustrated by the following incidents. _Illustrations._ 1st. Dr. Reid, in his work on "Ventilation of Rooms," relates that an innkeeper in London, when he provided a public dinner, always spread his tables in an under-ground room, with low walls, where the air was confined and impure. He assigned as a reason for so doing, that his guests consumed only one third as much food and wine, as if the tables were laid in the open air. 2d. A manufacturer stated before a committee of the British Parliament, that he had removed an arrangement for ventilating his mill, because he noticed that his men ate much more after his mill was ventilated, than previous to admitting fresh air into the rooms, and that he could not _afford_ to have them breathe pure air. _Observation._ Many of the cases of indigestion among clergymen, seamstresses, school teachers, sedentary mechanics, and factory operatives, are produced by breathing the impure air of the rooms they occupy. These cases can be prevented, as well as cured, by proper attention to ventilation. -=-=-=-=-=-=-=-=-=-=-=-= 325. What is observed of those individuals that restrict the movements of the abdominal muscles? 326. Why is pure air necessary to vigorous digestion? Give illustration 1st. Illustration 2d. What is one cause of indigestion among the sedentary class in community? -=-=-=-=-=-=-=-=-=-=-=-= 327. _The position of a person, in standing or sitting, exerts an influence upon the digestive organs._ If a person lean, or stoop forward, the distance between the pelvic bones and the diaphragm is diminished. This prevents the depression of the diaphragm, while the stomach, liver, pancreas, and other abdominal organs, suffer compression, which induces many severe diseases of these organs. As healthy and well-developed muscles keep the spinal column in an erect position, which conduces to the health of the organs of digestion, the child should be taught to avoid all positions _but the erect_, while studying or walking. This position, combined with unrestricted waists, will do much to remove the now prevalent disease, dyspepsia. 328. _Whatever kind of aliment is taken, it is separated into nutriment and residuum_; the former of which is conveyed, through the medium of the circulation, to all organs of the system, and the latter, if not expelled, accumulates, causing headache and dizziness, with a general uneasiness; and, if allowed to continue, it lays the foundation of a long period of suffering and disease. For the preservation of health, it is necessary that there should be a daily evacuation of the residual matter. _Observation._ In chronic diseases of the digestive organs, very frequently, there is an inactive, or costive condition of the alimentary canal. This may be removed in many cases, and relieved in all instances, by friction over the abdominal organs, and by making an effort at some stated period each day, (evening is best,) to evacuate the residuum. In acute diseases, as fever, regard should be given to regularity in relieving the intestines of residuum. Attention to this suggestion will in many instances obviate the necessity of cathartic medicine. -=-=-=-=-=-=-=-=-=-=-=-= 327. Why does the position of a person affect digestion? 328. Into what are different kinds of aliment separated? -=-=-=-=-=-=-=-=-=-=-=-= 329. We would add, for the benefit of those afflicted with hemorrhoids, or piles, that the best time for evacuating the intestinal canal would be immediately before retiring for the night. During the night, while recumbent, the protruding parts return to their proper place, and the surrounding organs acquire increased tone to retain them. The same observance will do much to prevent such prostrating diseases.[12] [12] The urinary organs, as well as the intestinal canal, should be frequently and regularly evacuated. Some most distressing and frequently incurable complaints are caused by false customs and false delicacy in this particular. Teachers should be particularly careful, and regard this suggestion in reference to young pupils. 330. To recapitulate: digestion is most perfect when the action of the cutaneous vessels is energetic; the brain and vocal organs moderately stimulated by animated conversation; the blood well purified; the muscular system duly exercised; the food of an appropriate quality, taken in proper quantities, at regular periods, and also properly masticated. -=-=-=-=-=-=-=-=-=-=-=-= 330. Give the summary when digestion is most perfect. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER VXII. THE CIRCULATORY ORGANS. 331. The ultimate object of the food and drink introduced into the body, is to furnish material to promote the growth and repair the waste of the organs of the system. The formation of chyle (the nutrient portion of the food) has been traced through the digestive process, and its transfer into the vein at the lower part of the neck, from which it is conveyed to the heart; and, finally, in the lungs it assimilates to the character of blood. 332. The BLOOD, after standing a short time, when drawn from its vessels, separates into _se´rum_, (a watery fluid,) and _co-ag´u-lum_, (clot.) This fluid is distributed to every part of the system. There is no part so minute that it does not receive blood. The organs by which this distribution is effected are so connected that there is properly neither beginning nor end; but as it respects their functions, they are connected in a complete circle. From this circumstance, they are called the _Circulatory Organs_. ANATOMY OF THE CIRCULATORY ORGANS. 333. The CIRCULATORY ORGANS are the _Heart_, _Ar´te-ries_, _Veins_, and _Cap´il-la-ries_. 334. The HEART is placed obliquely, in the left cavity of the chest, between the right and left lung. Its general form is that of an inverted cone, the base of which is directed upward and backward, toward the right shoulder, while its apex points forward to the left side, about three inches from the sternum to the space between the fifth and sixth ribs. Its under side rests upon the tendinous portion of the diaphragm. The heart is surrounded by a sac, called the _per-i-car´di-um_, (heart-case.) The interior surface of this membrane secretes a watery fluid, that lubricates the exterior of the heart, and obviates friction between it and the pericardium. -=-=-=-=-=-=-=-=-=-=-=-= 331. what is the ultimate object of the food? 332. Of what is the blood composed? What is said of the distribution of the blood? 333. Name the circulatory organs. 334-351. _Give the anatomy of the circulatory organs._ 334. Describe the heart. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 66. A front view of the heart. 1, The right auricle of the heart. 2, The left auricle. 3, The right ventricle. 4, The left ventricle. 5, 6, 7, 8, 9, 10, The vessels[13] through which the blood passes to and from the heart.] [Illustration: Fig. 67. A back view of the heart. 1, The right auricle. 2, The left auricle. 3, The right ventricle. 4, The left ventricle. 5, 6, 7, The vessels that carry the blood to and from the heart. 9, 10, 11, The nutrient vessels of the heart.] [13] All vessels that carry blood to the heart, are called _veins_. All vessels that carry blood _from_ the heart, are called _arteries_. -=-=-=-=-=-=-=-=-=-=-=-= With what is it surrounded? What is its use? How much fluid does this membrane contain when healthy? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ In health, there is usually about a tea-spoonful of fluid in the pericardium. When these parts are diseased, it may be thrown out more abundantly, and sometimes amounts to several ounces, producing a disease called dropsy of the heart. But all the unpleasant sensations in the region of the heart are not caused by an increased amount of fluid in the pericardium, as this disease is not of frequent occurrence. 335. The heart is composed of muscular fibres, that traverse it in different directions, some longitudinally, but most of them in a spiral direction. The human heart is a double organ, or it has two sides, called the right and the left. The compartments of the two sides are separated by a muscular _sep´tum_, or partition. Again, each side of the heart is divided into two parts, called the _Au´ri-cle_ (deaf ear) and the _Ven´tri-cle_. [Illustration: Fig. 68. A section of the heart, showing its cavities and valves. 3, The right auricle. 4, The opening between the right auricle and right ventricle. 5, The right ventricle. 6, The tricuspid valves. 7, The pulmonary artery. 9, The semilunar valves of the pulmonary artery. 10, The septum between the right and left ventricle. 12, The left auricle. 13, The opening between the left auricle and left ventricle. 14, The left ventricle. 15, The mitral valves. 16, The aorta. 17, The semilunar valves of the aorta.] 336. The AURICLES differ in muscularity from the ventricles. Their walls are thinner, and of a bluish color. These cavities are a kind of reservoir, designed to contain the blood arriving by the veins. 337. The VENTRICLES not only have their walls thicker than the auricles, but they differ in their internal structure. From the interior of these cavities arise fleshy columns, called _co-lum´næ car´ne-æ_. The walls of the left ventricle are thicker and stronger than those of the right. -=-=-=-=-=-=-=-=-=-=-=-= 335. Of what is the heart composed? Give its divisions. 336. Describe the auricles. 337. Describe the ventricles. -=-=-=-=-=-=-=-=-=-=-=-= 338. The cavities in the right side of the heart are triangular in shape; those of the left, oval. Each cavity will contain about two ounces of blood. Between the auricle and ventricle in the right side of the heart, there are three folds, or doublings, of thin, triangular membrane, called the _tri-cus´pid_ valves. Between the auricle and ventricle in the left side, there are two valves, called the _mi´tral_. There are seen passing from the floating edge of these valves to the columnæ carneæ, small white cords, called _chor´dæ ten´di-næ_, which prevent the floating edge of the valve from being carried into the auricle. 339. The right ventricle of the heart gives rise to the _Pul´mo-na-ry_ artery; the left ventricle, to a large artery called the _A-ort´a_. At the commencement of each of these arteries there are three folds of membrane, and from their shape, they are called _sem-i-lu´nar_ valves. 340. The heart is supplied with arteries and veins, which ramify between its muscular fibres, through which its _nutrient_ blood passes. It has, likewise, a few lymphatics, and many small nervous filaments from the sympathetic system of nerves. This organ, in its natural state, exhibits but slight indications of sensibility, and although nearly destitute of the sensation of touch, it is yet, however, instantly affected by every painful bodily excitement, or strong mental emotions. _Observation._ To obtain a clear idea of the heart and its valves, it is recommended to examine this part of an ox or calf. In order that each ventricle be opened without mutilating the fleshy columns, tendinous cords, and valves, cut on each side of the septum parallel to it. This may be easily found between the ventricles, as they differ in thickness. -=-=-=-=-=-=-=-=-=-=-=-= 338. How do the cavities in the heart differ? What is found between the auricle and ventricle in the right side of the heart? How many valves in the left side, and their names? Where are the tendinous cords, and what is their use? 339. What vessels proceed from the ventricles? What is said of their valves? 340. With what is the heart supplied? What is said of its sensibility? How can an idea of the structure of the heart be obtained? -=-=-=-=-=-=-=-=-=-=-=-= 341. The ARTERIES are the cylindrical tubes that convey the blood from the heart to every part of the system. They are dense in structure, and preserve, for the most part, the cylindrical form, when emptied of their blood, which is their condition after death. 342. The arteries are composed of three coats. The external, or cellular coat, is firm and strong; the middle, or fibrous coat, is composed of yellowish fibres. This coat is elastic, fragile, and thicker than the external coat. Its elasticity enables the vessel to accommodate itself to the quantity of blood it may contain. The internal coat is a thin, serous membrane, which lines the interior of the artery, and gives it the smooth polish which that surface presents. It is continuous with the lining membrane of the heart. 343. Communications between arteries are free and numerous. They increase in frequency with diminution in the size of the branches, so that through the medium of the minute ramifications, the entire body may be considered as one circle of inosculation. The arteries, in their distribution through the body, are enclosed in a loose, cellular investment, called a sheath, which separates them from the surrounding tissues. 344. The PULMONARY ARTERY commences in front of the origin of the aorta. It ascends obliquely to the under surface of the arch of the aorta, where it divides into two branches, one of which passes to the right, the other to the left lung. These divide and subdivide in the structure of the lungs, and terminate in the capillary vessels, which form a net-work around the air-cells, and become continuous with the minute branches of the pulmonary veins. This artery conveys the impure blood to the lungs, and, with its corresponding veins, establishes the _lesser_, or _pulmonic circulation_. -=-=-=-=-=-=-=-=-=-=-=-= 341. What are arteries? 342. Give their structure. 343. What is said of the communications between the arteries? In their distribution, how are they separated from the surrounding tissues? 344. Describe the pulmonary artery. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: The divisions of this artery continue to divide and subdivide, until they become no larger than hairs in size. These minute vessels pass over the air-cells, represented by small dark points around the margin of the lungs.] 345. The AORTA proceeds from the left ventricle of the heart, and contains the pure, or nutrient blood. This trunk gives off branches, which divide and subdivide to their ultimate ramifications, constituting the great arterial tree which pervades, by its minute subdivisions, every part of the animal frame. This great artery and its divisions, with their returning veins, constitute the _greater_, or _systemic circulation_. -=-=-=-=-=-=-=-=-=-=-=-= What does this artery and its corresponding veins establish? Explain fig. 69. 345. Describe the aorta. What do this artery and its corresponding veins constitute? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 70. The aorta and its branches. 1, The commencement of the aorta. 2, The arch of the aorta. 3, The carotid artery. 4, The temporal artery. 5, The subclavian artery. 6, The axillary artery. 7, The brachial artery. 8, The radial artery. 9, The ulnar artery. 10, The iliac artery. 11, The femoral artery. 12, The tibial artery, 13. The peroneal artery.] 346. The VEINS are the vessels which return the blood to the auricles of the heart, after it has been circulated by the arteries through the various tissues of the body. They are thinner and more delicate in structure than the arteries, so that when emptied of their blood, they become flattened and collapsed. The veins commence by minute radicles in the capillaries, which are every where distributed through the textures of the body, and coalesce to constitute larger and larger branches, till they terminate in the large trunks which convey the dark-colored blood directly to the heart. In diameter they are much larger than the arteries, and, like those vessels, their combined area would constitute an imaginary cone, the apex of which is placed at the heart, and the base at the surface of the body. -=-=-=-=-=-=-=-=-=-=-=-= What does fig. 70 represent? 346. What are the veins? -=-=-=-=-=-=-=-=-=-=-=-= 347. The communications between the veins are more frequent than between the arteries, and take place between the larger as well as among the smaller vessels. The office of these inosculations is very apparent, as tending to obviate the obstructions to which the veins are peculiarly liable, from the thinness of their coats, and from inability to overcome great impediments by the force of their current. These tubes, as well as the arteries, are supplied with nutrient vessels, and it is to be presumed that nervous filaments from the sympathetic nerves are distributed to their coats. 348. The external, or cellular coat of the veins, is dense and firm, resembling the cellular tunic of the arteries. The middle coat is fibrous, like that of the arteries, but extremely thin. The internal coat is serous, and also similar to that of the arteries. It is continuous with the lining membrane of the heart at one extremity, and with the lining membrane of the capillaries at the other. 349. At certain intervals, the internal coat forms folds, or duplicatures, which constitute valves. They are generally composed of two semilunar folds, one on each side of the vessel. The free extremity of the valvular folds is concave, and directed forward, so that while the current of blood sets toward the heart, they present no impediment to its free passage; but let the current become retrograde, and it is impeded by their distention. The valves are most numerous in the veins of the extremities, particularly the deeper veins situated between the muscles; but in some of the larger trunks, and also in some of the smaller veins, no valves exist. -=-=-=-=-=-=-=-=-=-=-=-= Where do they commence? 347. What is said of their communications? What is the apparent design of the inosculations of the veins? What vessels are distributed to the coats of the veins? 348. Give the structure of the coats of the veins. 349. How are the valves in the veins formed? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 71. A vein laid open to show the valves. 1, The trunk of the vein. 2, 2, Its valves. 3, An opening of a branch into the main trunk.] -=-=-=-=-=-=-=-=-=-=-=-= What is their use? Where are they the most numerous? -=-=-=-=-=-=-=-=-=-=-=-= 350. The CAPILLARIES constitute a microscopic net-work, and are so distributed through every part of the body as to render it impossible to introduce the smallest needle beneath the skin, without wounding several of these fine vessels. They are remarkable for the uniformity of diameter, and for the constant divisions and communications which take place between them. 351. The capillaries inosculate, on the one hand, with the terminal extremity of the arteries, and on the other, with the commencement of the veins. They establish the communication between the termination of the arteries and the beginning of the veins. The important operations of secretion and the conversion of the nutrient materials of the blood into bone, muscle, &c., are performed in these vessels. [Illustration: Fig. 72. An ideal view of a portion of the pulmonic circulation. 1, 1, A branch of the artery that carries the impure blood to the lungs. 3, 3, Capillary vessels. 2, 2, A vein through which red blood is returned to the left side of the heart.] [Illustration: Fig. 73. An ideal view of a portion of the systemic circulation. 1, 1, A branch of the aorta. This terminates in the capillaries, (3, 3.) 2, 2, A vein through which the impure blood is carried to the right side of the heart.] -=-=-=-=-=-=-=-=-=-=-=-= 350. What do the capillaries constitute? For what are they remarkable? 351. What relation do they bear to the arteries and veins? What important operations are performed in these vessels? What is represented by fig. 72? By fig. 73? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XVIII. PHYSIOLOGY OF THE CIRCULATORY ORGANS. 352. The walls of all the cavities of the heart are composed of muscular fibres, which are endowed with the property of contracting and relaxing, like the muscles of the extremities. The contraction and relaxation of the muscular tissue of the heart, produce a diminution and enlargement of both auricular and ventricular cavities. The auricles contract and dilate simultaneously, and so do the ventricles; yet the contraction and dilatation of the auricles do not alternate with the contraction and dilatation of the ventricles, as the dilatation of the one is not completed before the contraction of the other commences. The dilatation of the ventricles is termed the _di-as´to-le_ of the heart; their contraction, its _sys´to-le_. 353. The ventricles contract quicker and more forcibly than the auricles, and they are three times longer in dilating than contracting. The walls of the right ventricle, being thinner than the left, are more distensible, and thus this cavity will contain a greater amount of blood. This arrangement adapts it to the venous system, which is more capacious than the arterial. The thicker and more powerful walls of the left ventricle adapt it to expel the blood to a greater distance. 354. The valves in the heart permit the blood to flow from the auricles to the ventricles, but prevent its reflowing. The valves at the commencement of the aorta and pulmonary artery, permit the blood to flow from the ventricles into these vessels, but prevent its returning. -=-=-=-=-=-=-=-=-=-=-=-= 352-366. _Give the physiology of the circulatory organs._ 352. What do the contraction and relaxation of the muscular walls of the heart produce? How do the auricles and ventricles contract and dilate? 353. What is said of the contraction and dilatation of the ventricles in the heart? How is the right ventricle adapted to its function? How the left? 354. What is the use of the valves in the heart? Those of the aorta and pulmonary artery? -=-=-=-=-=-=-=-=-=-=-=-= 355. The function of the different parts of the heart will be given, by aid of fig. 74. The blood passes from the right auricle (3) into the right ventricle, (5,) and the tricuspid valves (6) prevent its reflux; from the right ventricle the blood is forced into the pulmonary artery, (7,) through which it passes to the lungs. The semilunar valves (9) prevent this circulating fluid returning to the ventricle. The blood, while passing over the air-cells in the lungs, in the minute divisions of the pulmonary artery, is changed from a bluish color to a bright red. It is then returned to the left auricle of the heart by the pulmonary veins, (11, 11.) [Illustration: Fig. 74. 1, The descending vena cava, (vein.) 2, The ascending vena cava, (vein.) 3, The right auricle. 4, The opening between the right auricle and the right ventricle. 5, The right ventricle. 6, The tricuspid valves. 7, The pulmonary artery. 8, 8, The branches of the pulmonary artery that pass to the right and left lung. 9, The semilunar valves of the pulmonary artery. 10, The septum between the two ventricles of the heart. 11, 11, The pulmonary veins. 12, The left auricle. 13, The opening between the left auricle and ventricle. 14, The left ventricle. 15, The mitral valves. 16, 16, The aorta. 17, The semilunar valves of the aorta.] -=-=-=-=-=-=-=-=-=-=-=-= 355. Describe the course of the blood from the right auricle in the heart to the lungs. -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ If the blood is not changed in the lungs, it will not flow to the pulmonary veins. This phenomenon is seen in instances of death from drowning, strangling, carbonic acid, &c. The same is true, but in a less degree, of individuals whose apparel is tight, as well as of those who breathe impure air, or have diseased lungs. 356. The left auricle, (12,) by its contraction, forces the blood into the left ventricle, (14.) The mitral valves (15) prevent its reflowing. From the left ventricle the blood is forced into the aorta, (16,) through which, and its subdivisions, it is distributed to every part of the system. The semilunar valves (17) prevent its returning. _Observation._ The parts of the circulatory organs most liable to disease are the valves of the heart, particularly the mitral. When these membranous folds become ossified or ruptured, the blood regurgitates, and causes great distress in breathing. The operations of the system are thus disturbed as the movements of the steam engine would be if its valves were injured, or did not play freely. 357. The difference between the functions of the pulmonary artery and aorta is, the former communicates with the right ventricle of the heart, and distributes only impure blood to the lungs; the other connects with the left ventricle of the heart, and distributes pure blood to the whole body, the lungs not excepted. At the extremity of the divisions of the aorta, as well as the pulmonary artery, are found capillary vessels. This curious net-work of vessels connects with the minute veins of the body, which return the blood to the heart. _Observation._ The function of the veins of the systemic circulation is similar to the office of the arteries in the lungs, and that the veins of the pulmonic circulation transmit to the heart the pure, or nutrient blood, and thus supply the arteries of the general system with assimilating fluid. -=-=-=-=-=-=-=-=-=-=-=-= What is the effect when the blood is not changed in the lungs? 356. Describe the circulation of the blood from the left auricle to the general system. What part of the circulatory organs is most liable to disease? What is the effect when the valves are diseased? 357. Give the difference in the functions of the pulmonary artery and aorta. Show the relation between the functions of the arteries and veins both of the pulmonic and systemic circulation. -=-=-=-=-=-=-=-=-=-=-=-= 358. The veins that receive the blood from all parts of the body, follow nearly the same course as the arteries. The myriads of these small vessels beneath the skin, and others that accompany the arteries, at last unite and form two large trunks, called _ve´na ca´va as-cend´ens_, and _de-scend´ens_. _Observation._ A peculiarity is presented in the veins which come from the stomach, spleen, pancreas, and intestines. After forming a large trunk, they enter the liver, and ramify like the arteries, and in this organ they again unite into a trunk, and enter the ascending vein, or cava, near the heart. This is called the portal circulation. 359. The ventricles of the heart contract, or the "pulse" beats, about seventy-five times every minute; in adults; in infants, more than a hundred times every minute; in old persons, less than seventy-five times every minute. The energy of the contraction of this organ varies in different individuals of the same age. It is likewise modified by the health and tone of the system. It is difficult to estimate the muscular power of the heart; but, comparing it with other muscles, and judging from the force with which blood is ejected from a severed artery, it must be very great. _Observation._ The phenomenon known under the name of pulse, is the motion caused by the pressure of the blood against the coats of the arteries at each contraction of the ventricles. 360. The following experiment will demonstrate that the blood flows from the heart. Apply the fingers upon the artery at the wrist, at two different points, about two inches apart; if the pressure be moderately made, the "pulse" will be felt at both points. Let the point nearest the heart be pressed firmly, and there will be no pulsation at the lower point; but make strong pressure upon the lower point only, and the pulsation will continue at the upper point, proving that the blood flows from the heart, in the arteries, to different parts of the system. -=-=-=-=-=-=-=-=-=-=-=-= 358. What is the course of the veins? What peculiarity is observable in the veins of the liver? 359. How often does the heart contract, or the pulse beat, in adults? In infants? In old persons? What is said of the energy of its contraction in different persons? How is the pulse produced? 360. Demonstrate by experiment that the blood flows from the heart. -=-=-=-=-=-=-=-=-=-=-=-= 361. There are several influences, either separately or combined that propel the blood from the heart through the arteries, among which may be named,--1st. The contraction of the muscular walls of the heart. 2d. The contractile and elastic middle coat of the arteries aids the heart in impelling the blood to the minute vessels of the system. 3d. The peculiar action of the minute capillary vessels is considered, by some physiologists, as a motive power in the arterial circulation. 4th. The pressure of the muscles upon the arteries, when in a state of contraction, is a powerful agent, particularly when they are in active exercise. 362. The following experiments will demonstrate that the blood from every part of the system flows to the heart by the agency of the veins. 1st. Press firmly on one of the veins upon the back of the hand, carrying the pressure toward the fingers; for a moment, the vein will disappear. On removing the pressure of the finger, it will reappear, from the blood rushing in from below. 2d. If a tape be tied around the arm above the elbow, the veins below will become larger and more prominent, and also a greater number will be brought in view, while the veins above the tape are less distended. At this time, apply the finger at the wrist, and the pulsation of the arteries still continues, showing that the blood is constantly flowing from the heart through the arteries, into the veins; and the increased size of the veins shows that the pressure of the tape prevents its flowing back to the heart. -=-=-=-=-=-=-=-=-=-=-=-= 361. State the influences that propel the blood from the heart. 362. Demonstrate by the first experiment that the blood flows to the heart. By the second experiment. -=-=-=-=-=-=-=-=-=-=-=-= 363. The influences that return the blood to the heart through the veins, are not so easily understood as those that act on the blood in the arteries. Some physiologists have imputed an active propulsive power to the capillary vessels in carrying the blood through the veins. This is not easily explained, and perhaps it is as difficult to understand. An influence upon which others have dwelt, is the suction power of the heart in active dilatation, acting as a _vis a fronte_ (power in front) in drawing blood to it. 364. Another influence that aids the venous circulation is attributed to the propulsive power of the heart. It is not easy to comprehend how this power of the heart can be extended through the capillary vessels to the blood in the veins. Again, an important agency has been found, by some physiologists, in the inspiratory movements, which are supposed to draw the blood of the veins into the chest, in order to supply the vacuum which is created there by the elevation of the ribs and the descent of the diaphragm. 365. One of the most powerful causes which influence the venous circulation, is the frequently-recurring action of the muscles upon the venous trunks. When the muscles are contracted, they compress that portion of the veins which lie beneath the swell, and thus force the blood from one valve to the other, toward the heart. When they are relaxed, the veins refill, and are compressed by the recurring action of the muscles. _Observation._ The physician, in opening a vein, relies on the energetic contractions and sudden relaxations of the muscles, when he directs the patient to clasp the head of a cane, or the arm of a chair; these alternate motions of the muscles cause an increased flow of blood to the veins of the ligated arm. -=-=-=-=-=-=-=-=-=-=-=-= 363. What is said of the influences that return the blood to the heart? What is said of the propulsive power of the capillaries? Of the suction power of the heart? 364. Give another influence. State another agency. 365. What is one of the most powerful causes which influence venous circulation? Give practical observation. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 75. An ideal view of the circulation in the lungs and system. From the right ventricle of the heart, (2,) the dark, impure blood is forced into the pulmonary artery, (3,) and its branches (4, 5) carry the blood to the left and right lung. In the capillary vessels (6, 6) of the lungs, the blood becomes pure, or of a red color, and is returned to the left auricle of the heart, (9,) by the veins, (7, 8.) From the left auricle the pure blood passes into the left ventricle, (10.) By a forcible contraction of the left ventricle of the heart, the blood is thrown into the aorta, (11.) Its branches (12, 13, 13) carry the pure blood to every organ or part of the body. The divisions and subdivisions of the aorta terminate in capillary vessels, represented by 14, 14. In these hair-like vessels the blood becomes dark colored, and is returned to the right auricle of the heart (1) by the vena cava descendens, (15,) and vena cava ascendens, (16.) The tricuspid valves (17) prevent the reflow of the blood from the right ventricle to the right auricle. The semilunar valves (18) prevent the blood passing from the pulmonary artery to the right ventricle. The mitral valves (19) prevent the reflow of blood from the left ventricle to the left auricle. The semilunar valves (20) prevent the reflow of blood from the aorta to the left ventricle.] 366. The muscles exercise an agency in maintaining the venous circulation at a point above what the heart could perform. As the pulsations are diminished by rest, so they are accelerated by exercise, and very much quickened by violent effort. There can be little doubt that the increased rapidity of the return of blood through the veins, is, of itself, a sufficient cause for the accelerated movements of the heart during active exercise. _Observation._ The quantity of blood in different individuals varies. From twenty-five to thirty-five pounds may be considered an average estimate in a healthy adult of medium size. The time in which the blood courses through the body and returns to the heart, is different in different individuals. Many writers on physiology unconditionally limit the period to three minutes. It is undeniable that the size and health of a person, the condition of the heart, lungs, and brain, the quantity of the circulating fluid, the amount and character of the inspired air, and the amount of muscular action, exert a modifying influence. The time probably varies from three to eight minutes. -=-=-=-=-=-=-=-=-=-=-=-= 366. What causes the accelerated movements of the heart during active exercise? -=-=-=-=-=-=-=-=-=-=-=-= _Note._ Let the pupil review the anatomy and physiology of the circulatory organs from fig. 75, or from anatomical outline plates, No. 6 and 7. CHAPTER XIX. HYGIENE OF THE CIRCULATORY ORGANS 367. If any part of the system is deprived of blood, its vitality will cease; but, if the blood is lessened in quantity to a limited extent, only the vigor and health of the part will be impaired. The following conditions, if observed, will favor the free and regular supply of blood to all portions of the system. 368. _The clothing should be loosely worn._ Compression of any kind impedes the passage of blood through the vessels of the compressed portion. Hence, no article of apparel should be worn so as to prevent a free flow of blood through every organ of the body. 369. The blood which passes to and from the brain, flows through the vessels of the neck. If the dressing of this part of the body is close, the circulation will be impeded, and the functions of the brain will be impaired. This remark is particularly important to scholars, public speakers, and individuals predisposed to apoplexy, and other diseases of the brain. 370. As many of the large veins lie immediately beneath the skin, through which the blood is returned from the lower extremities, if the ligatures used to retain the hose, or any other article of apparel, in proper position, be tight and inelastic, the passage of blood through these vessels will be obstructed, producing, by their distention, the varicose, or enlarged veins. Hence elastic bands should always be used for these purposes. -=-=-=-=-=-=-=-=-=-=-=-= 367-386. _Give the hygiene of the circulatory organs._ 367. What effect will be produced on the body if it is deprived of blood? If the blood is only lessened in quantity? 368. Why should the clothing be worn loose? 369. What is said of dressing the neck? To what persons is this remark applicable? 370. How are enlarged veins frequently produced? -=-=-=-=-=-=-=-=-=-=-=-= 371. _An equal temperature of all parts of the system promotes health._ A chill on one portion of the body diminishes the size of its circulating vessels, and the blood which should distend and stimulate the chilled part, will accumulate in other organs. The deficiency of blood in the chilled portion induces weakness, while the superabundance of sanguineous fluid may cause disease in another part of the system. 372. _The skin should be kept not only of an equal, but at its natural temperature._ If the skin is not kept warm by adequate clothing, so that chills shall not produce a contraction of the blood-vessels and a consequent paleness, the blood will recede from the surface of the body, and accumulate in the internal organs. Cleanliness of the skin is likewise necessary, for the reason, that this condition favors the free action of the cutaneous vessels. _Observation._ When intending to ride in a cold day, wash the face, hands, and feet, in cold water, and rub them smartly with a coarse towel. This is far better to keep the extremities warm, than to take spirits into the stomach. 373. _Exercise promotes the circulation of the blood._ As the action of the muscles is one of the important agents which propel the blood through the arteries and veins, daily and regular exercise of the muscular system is required to sustain a vigorous circulation in the extremities and skin, and also to maintain a healthy condition of the system. The best stimulants to improve the sluggish circulation of an indolent patient, whose skin is pale and whose extremities are cold, are the union of vigorous muscular exercise with agreeable mental action, and the systematic application to the skin of cold water, attended with friction. -=-=-=-=-=-=-=-=-=-=-=-= 371. Why should the temperature of the body be equal? 372. Why should the skin be kept at its natural, as well as at an equal temperature? What practical observation when intending to ride in a cold day? 373. Why does exercise promote health? What are good stimulants for sluggish circulation in the indolent? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ The coach-driver and teamster throw their arms around their bodies to warm them when cold. The muscles that are called into action in swinging the arms, force a greater quantity of blood into the chilled parts, and consequently, more heat is produced. 374. When a number of muscles are called into energetic action, a greater quantity of blood will be propelled to the lungs and heart in a given time, than when the muscles are in a state of comparative inaction. It is no uncommon occurrence, that before there is a proper expansion of the respiratory organs to correspond with the frequency and energy of the movements of the muscles, there is an accumulation of blood in the lungs, attended by a painful sensation of fulness and oppression in the chest, with violent and irregular action of the heart. This condition of the organs of the chest, called _congestion_, may be followed by cough, inflammation of the lungs, asthma, and a structural disease of the heart. 375. To avoid these sensations and results, when we feel necessitated to walk or run a considerable distance in a short time, commence the movements in a moderate manner increasing the speed as the respiratory movements become more frequent and their expansion more extensive, so that a sufficient amount of air may be received into the lungs to purify the increased quantity of blood forced into them. The same principles should be observed when commencing labor, and in driving horses and other animals. _Observation._ When a large number of muscles are called into action after repose, as when we rise from a recumbent or sitting posture, the blood is impelled to the heart with a very strong impetus. If that organ should be diseased, it may arrive there in larger quantities than can be disposed of, and death may be the result. Hence the necessity of avoiding all sudden and violent movements, on the part of those who have either a functional or structural disease of the heart. -=-=-=-=-=-=-=-=-=-=-=-= Mention the illustration. 374. What is the effect when a number of muscles are called into energetic action? What effect has this accumulation of blood in the lungs? 375. How can such disagreeable sensations be avoided? Mention a practical observation. -=-=-=-=-=-=-=-=-=-=-=-= 376. _The mind exercises no inconsiderable influence upon the circulatory organs._ When an individual is stimulated by hope, or excited by anger, the heart beats more forcibly, and the arteries act more energetically, than when a person is influenced by fear, despair, or sorrow. Consequently, the system is more fully nourished, and capable of greater exertion, when the former condition obtains, than when the latter exists. 377. _The quality and quantity of the blood modify the action of the heart and blood-vessels._ If this fluid is abundant and pure, the circulatory vessels act with more energy than when it is deficient in quantity or defective in quality. _Illustrations._ 1st. In an athletic man, whose heart beats forcibly, and whose pulse is strong, if a considerable quantity of blood is drawn from a vein, as in bleeding, the heart will beat feebly, and the pulse will become weak. 2d. When the blood is made impure by inhaling vitiated air, the action of the heart and arteries is diminished, which produces an effect similar to that which takes place when blood is drawn from a vein. 378. _Hemorrhage from divided arteries should be immediately arrested._ When large blood-vessels are wounded or cut, the flow of blood must be immediately stopped, or the person soon faints, and the heart ceases its action. If it is a large artery that is wounded, the blood will be thrown out in jets, or jerks, every time the pulse beats. The flow of blood can be stopped until a surgeon arrives, either by compressing the vessel between the wound and the heart, or by compressing the end of the divided artery in the wound. -=-=-=-=-=-=-=-=-=-=-=-= 376. State some of the effects that the mind has on circulation. 377. What effect have the quantity and quality of blood upon the circulatory organs? Give illustration 1st. Illustration 2d. 378. What is necessary when large blood-vessels are wounded or cut? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 76. The track of the large artery of the arm. 1, The collar-bone. 9, The axillary artery. 10, The brachial artery.] [Illustration: Fig. 77. B, The manner of compressing the artery near the collar-bone. A, The manner of compressing the large artery of the arm, with the fingers. C, The manner of compressing the divided extremity of an artery in the wound, with a finger.] 379. After making compression with the fingers, as described and illustrated, take a piece of cloth or handkerchief, twist it cornerwise, and tie a hard knot midway between the two ends. This knot should be placed over the artery, between the wound and the heart, and the ends carried around the limb and loosely tied. A stick, five or six inches long, should be placed under the handkerchief, which should be twisted until the knot has made sufficient compression on the artery to allow the removal of the fingers without a return of bleeding. Continue the compression until a surgeon can be called. -=-=-=-=-=-=-=-=-=-=-=-= What is shown by fig. 76? By fig. 77? 379. What is to be done after compressing the wound, as before described? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 78. A, B, The track of the large artery of the arm. The figure exhibits the method of applying the knotted handkerchief to make compression on this artery.] [Illustration: Fig. 79. A, C, The track of the large artery of the thigh. B, The method of applying the knotted handkerchief to compress this artery. In practice, the twisting stick B should be placed opposite the knot over the artery A, C.] 380. When an artery of the arm is cut, elevating the wounded limb above the head will tend to arrest the flow of blood. In a wound of a lower limb, raise the foot, so that it shall be higher than the hip, until the bleeding ceases. _Illustration._ On one occasion, the distinguished Dr. Nathan Smith was called to a person who had divided one of the large arteries below the knee. After trying in vain to find the bleeding vessel, so as to secure it, he caused the foot to be elevated higher than the hip. At the first instant the blood was forced from the wound about twelve inches; in a minute, it was diminished to three or four; and, in a short time, the bleeding ceased. This Dr. S. called his "_great_" operation; and it was truly great in _simplicity_ and _science_. -=-=-=-=-=-=-=-=-=-=-=-= What is shown by fig. 78 and 79? 380. What suggestion relative to the position of a limb when bleeding? Relate a simple operation by Dr. Nathan Smith. -=-=-=-=-=-=-=-=-=-=-=-= 381. The practical utility of every person knowing the proper means of arresting hemorrhage from severed arteries, is illustrated by the following incidents. In 1848, in the town of N., Mass., a mechanic divided the femoral artery; although several adult persons were present, he died in a few minutes from loss of blood, because those persons were ignorant of the method of compressing severed arteries until a surgeon could be obtained. 382. In 1846, a similar accident occurred in the suburbs of Philadelphia. While the blood was flowing copiously, a lad, who had received instruction on the treatment of such accidents at the Philadelphia High School, rushed through the crowd that surrounded the apparently dying man, placed his finger upon the divided vessel, and continued the compression until the bleeding artery was secured by a surgeon. 383. In "flesh wounds," when no large blood-vessel is divided, wash the part with cold water, and, when bleeding has ceased, draw the incision together, and retain it with narrow strips of adhesive plaster. These should be put on smoothly, and a sufficient number applied to cover the wound. In most instances of domestic practice, the strips of adhesive plaster are too wide. They should not exceed in width one fourth of an inch. Then apply a loose bandage, and avoid all "healing salves," ointments, and washes. In removing the dressing from a wound, both ends of the strips of plaster should be raised and drawn toward the incision. The liability of the wound re-opening is thus diminished. -=-=-=-=-=-=-=-=-=-=-=-= 381. Relate the first incident showing the utility of every person knowing the proper method of arresting the flow of blood from divided arteries. 382. The second incident. 383. How should "flesh wounds" be dressed? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ The union of the divided parts is effected by the action of the divided blood-vessels, and not by salves and ointments. The only object of the dressing is to keep the parts together, and protect the wound from air and impurities. _Nature_, in all cases of injuries, performs her own cure. Such simple wounds do not generally require a second dressing and should not be opened until the incisions are healed. [Illustration: Fig. 80. The manner in which strips of adhesive plaster are applied to wounds.] 384. In wounds made by pointed instruments, as a nail, or in lacerated wounds, as those made by forcing a blunt instrument, as a hook, into the soft parts, there will be no direct and immediate union. In these cases, apply a soothing poultice, as one made of linseed meal, and also keep the limb still. It is judicious to consult a physician immediately, in punctured or lacerated wounds, because they often induce the most dangerous diseases. 385. Wounds caused by the bite of rabid animals or venomous serpents, should be immediately cleansed with pure water. In many instances, the application of suction, either with "cupping glasses," or the mouth, will prevent the introduction of the poisonous matter into the system by absorption. When this is effected, cover the wound with a soothing poultice, as one made of slippery elm bark. -=-=-=-=-=-=-=-=-=-=-=-= What should be avoided? How should the strips of plaster be removed from a wound? How is the union of the divided parts effected? 384. How should punctured and lacerated wounds be dressed? 385. What is the treatment of wounds caused by the bite of rabid animals? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Although animal poisons, when introduced into the circulating fluid through the broken surface of the skin, frequently cause death, yet they can be taken into the mouth and stomach with impunity, if the mucous membrane which lines these parts is not broken. [Illustration: Fig. 81. _a_, _a_, Representation of wounds on the back part of the arm and fore-arm _b_, _b_, Wounds on the anterior part of the arm and fore-arm. By bending the elbow and wrist, the incisions at _a_, _a_, are opened, while those at _b_, _b_, are closed. Were the arm extended at the elbow and wrist, the wounds at _a_, _a_, would be closed, and those at _b_, _b_, would be opened.] 386. The proper position of the limbs favors the union of wounds. If the incision be upon the anterior part of the leg, between the knee and ankle, extending the knee and bending the ankle will aid its closing. If it be upon the back part of the leg, by extending the foot and bending the knee, the gaping of the incision will be diminished. When wounds occur upon the trunk or upper extremities, let the position of the person be regarded. -=-=-=-=-=-=-=-=-=-=-=-= 386 Does the proper position of the limbs favor the union of wounds? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XX. ABSORPTION. 387. ABSORPTION is the process by which the materials of nutrition are removed from the alimentary canal, to be conveyed into the circulatory vessels. It is likewise the process by which the particles of matter that have become injurious, or useless, are removed from the mass of fluids and solids of which the body is composed. These renovating and removing processes are performed by two sets of vessels ANATOMY OF THE LYMPHATIC VESSELS. 388. The vessels that act exclusively for the growth and renovation of the system, are found only in the alimentary canal. They are called lacteals. The vessels whose sole function is to remove particles of matter already deposited, are called _Lym-phat´ics_. The radicles, or commencement of the veins, in many, and it may be in all parts of the body, perform the office of absorption. _Observation._ This fact accounts for the capacity of the venous system exceeding the arterial. Had the veins no other function to perform, beside returning the blood that had been distributed by the arteries, it would be reasonable to suppose that this system would be less than the arterial, but the reverse is known to be true. 389. The LYMPHATIC VESSELS, in structure, resemble the lacteals. They exist in great numbers in the skin and mucous membranes, particularly those of the lungs. Though no lymphatics have been traced to the brain, it is presumed that they exist there, as this part of the body is not exempt from the composition and decomposition, which are perpetual in the body. These vessels are extremely minute at their origin, so that in many parts of the system they cannot be detected without the aid of a microscope. -=-=-=-=-=-=-=-=-=-=-=-= 387. Define absorption. 388-391. _Give the anatomy of the lymphatic vessels._ 388. What are those vessels called that act exclusively for the growth and renovation of the body? Those whose office is to remove the atoms already deposited? What other vessels perform the office of absorption? Give observation. 389. Describe the lymphatics. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 82. A single lymphatic vessel, much magnified.] [Illustration: Fig. 83. The valves of a lymphatic trunk.] [Illustration: Fig. 84. 1, A lymphatic gland with several vessels passing through it.] 390. The lymphatic vessels, like the veins, diminish in number as they increase in size, while pursuing their course toward the large veins near the heart, into which they pour their contents. The walls of these vessels have two coats of which the external one is cellular, and is capable of considerable distention. The internal coat is folded so as to form valves, like those in the veins. Their walls are so thin, that these folds give them the appearance of being knotted. -=-=-=-=-=-=-=-=-=-=-=-= What is represented by fig. 82? By fig. 83? By fig. 84? 390. In what respect do these vessels resemble the veins of the system? Give the structure of their coats. -=-=-=-=-=-=-=-=-=-=-=-= 391. At certain points, the lymphatic vessels pass through distinct, soft bodies, peculiar to themselves, which are called _lymphatic glands_, which are to these vessels what the mesenteric glands are to the lacteals. The lymphatic glands vary in form and in size. They are extremely vascular, and appear to consist of a collection of minute vessels. These glands are found in different parts of the body, but are most numerous in the groins, axilla, or arm-pits, neck, and cavities of the chest and abdomen. _Observation._ From exposure to cold, these glands are frequently enlarged and inflamed. They are known under the name of "kernels." They are often diseased, particularly in scrofula, or "king's evil." PHYSIOLOGY OF THE LYMPHATIC VESSELS. 392. Though the lacteals and lymphatics resemble each other in their structure and termination, yet they differ as to the nature of the fluids which they convey, as well as the nature of their functions. The lacteals open into the small intestine, and possess the power of rejecting all substances in the passing aliment, but the chyle. The lymphatics, on the contrary, not only imbibe all the various constituents of the body, both fluid and solid, but they sometimes absorb foreign and extraneous substances, when presented to their mouths, as in vaccination. 393. The varieties of absorption are, the _In-ter-sti´tial_, _Rec-re-men-ti´tial_, _Ex-cre-men-ti´tial_, _Cu-ta´ne-ous_, _Res-pi´ra-to-ry_, _Ve´nous_, and the _Lac´te-al_. -=-=-=-=-=-=-=-=-=-=-=-= 391. Describe the lymphatic glands. What observation is given in regard to these glands? 392-403. _Give the physiology of the lymphatic vessels._ 392. Explain the difference between the lacteals and lymphatics 393. Name the varieties of absorption. -=-=-=-=-=-=-=-=-=-=-=-= 394. INTERSTITIAL absorption is that change which is constantly going on in the animal economy among the particles of matter of which every texture is composed. The ordinary functions of the body, in health, require incessant action of the lymphatics; the circulatory system, with its myriads of small vessels, is constantly depositing new atoms of matter, which become vitalized, and perform a course of actions, then die, or become useless. These old atoms are removed by the absorbent system. Thus, wherever there is a minute artery to deposit a living particle of matter, there is a lymphatic vessel, or venous radicle, to remove it as soon as it shall have finished its particular office. 395. The action of the lymphatic vessels counterbalances those of nutrition, and thus the form and size of every part of the body is preserved. When their action exceeds that of the nutrient vessels, the body emaciates; when it is deficient, plethora is the result. In youth, they are less active than the nutrient vessels, and the limbs are plump; but in later periods of life, we find these actions reversed, and the body diminishes in size. It is not unfrequent that wens, and other tumors of considerable size, disappear, and even the entire bone of a limb has been removed from the same general cause. The effused fluids of bruises are also removed by absorption. _Observations._ 1st. When little or no food is taken into the stomach, life is supported by the lymphatic vessels and veins imbibing the fat and reconveying it into the blood vessels. It is the removal of this secretion which causes the emaciation of the face and extremities of a person recovering from a fever. In consumption, the extreme attenuation of the limbs is caused by the absorption, not only of the fat, but also of the muscles and more solid parts of the system. -=-=-=-=-=-=-=-=-=-=-=-= 394. What is interstitial absorption? Flow are the new atoms of matter deposited? How removed? 395. What vessels do the lymphatics counterbalance in action? What is the result when their action exceeds that of the nutrient vessels? When it is less? Mention some instances of active absorption. What causes the emaciated limbs of a person recovering from fever? The extreme attenuation in consumption? -=-=-=-=-=-=-=-=-=-=-=-= 2d. Animals which live in a half torpid state during the winter, derive their nourishment from the same source. In other words, we may say the starving animal lives for a time upon itself, eating up, by internal absorption, such parts of the body as can be spared under urgent necessity, to feed those organs and continue those functions that are absolutely essential to life. 396. RECREMENTITIAL absorption is the removal of those fluids from the system, which are secreted upon surfaces that have no external outlet. These fluids are various, as the fat, the marrow, the synovia of joints, serous fluids, and the humors of the eye. Were it not for this variety of absorption, dropsy would generally exist in the cavities of the brain, chest, and abdomen, from the continued action of the secretory vessels. 397. EXCREMENTITIAL absorption relates to the fluids which have been excreted, such as the bile, pancreatic fluid, saliva, milk, and other secretions. 398. CUTANEOUS absorption relates to the skin. Here the lymphatic vessels extend only to the cuticle, which they do not permeate. There has been much diversity of opinion on the question of cutaneous absorption; some maintaining that this membrane absorbs, while others deny it. Many experiments have proved that the skin may absorb sufficient nutriment to support life for a time, by immersing the patient in a bath of milk or broth. It has been found that the hand, immersed to the wrist in warm water, will absorb from ninety to one hundred grains of fluid in the space of an hour. 399. Thirst may be quenched by applying moist clothes to the skin, or by bathing. It is no uncommon occurrence, during a passage from one continent to the other, for the saliva to become bitter by the absorption of sea water. Medicinal substances, such as mercury, morphine, and Spanish flies, are frequently introduced into the system through the skin. -=-=-=-=-=-=-=-=-=-=-=-= 396. What is recrementitial absorption? 397. Define excrementitial absorption. 393. To what does cutaneous absorption relate? Is there a diversity of opinion respecting this variety of absorption? What do well attested experiments show? 399. What remark in reference to quenching thirst? What agency conveys medicinal substances and ointments into the system when tabbed on the skin? -=-=-=-=-=-=-=-=-=-=-=-= 400. RESPIRATORY absorption has reference to the lungs. The mucous membrane of these organs is abundantly supplied with lymphatic vessels. By their action, substances finely pulverized, or in the form of gas, are readily imbibed when inhaled into the lungs, such as metallic vapors, odoriferous particles, _tobacco smoke_, and other effluvia. In this way, contagious diseases are frequently contracted. _Illustration._ In inhaling sulphuric ether, or letheon, it is introduced into the vessels of the lungs in the form of vapor, and through them it is rapidly conveyed to the brain, and thus influences the nervous system. 401. VENOUS absorption is the function which the veins perform in absorbing from the alimentary canal liquids of various kinds that have been taken into the stomach and are not converted into chyle. In other parts of the body, they also perform the common office of lymphatics. 402. LACTEAL, or digestive absorption has reference to the absorption of chyle only, which is destined for the nutrition of the body. 403. Absorption is not only very abundant, but generally very rapid, and all these varieties are maintained through life, except when suspended by disease. -=-=-=-=-=-=-=-=-=-=-=-= 400. What is said of respiratory absorption? How is letheon introduced into the system? 401. Define venous absorption. 402. What is lacteal absorption? 403. What is said of absorption? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 85. A representation of the lymphatic vessels and glands. 1, 2, 3, 4, 5, 6, The lymphatic vessels and glands of the lower limbs. 7, Lymphatic glands. 8, The commencement of the thoracic duct. 9, The lymphatics of the kidney. 10, Of the stomach. 11, Of the liver. 12, 12, Of the lungs. 13, 14, 15, The lymphatics and glands of the arm. 16, 17, 18, Of the face and neck. 19, 20, Large veins. 21, The thoracic duct. 26, The lymphatics of the heart.] HYGIENE OF THE LYMPHATIC VESSELS. 404. By the action of the lymphatics, substances of an injurious, as well as of a beneficial, character may be conveyed into the system. These vessels, under certain conditions, are more active in their office than at other periods; and it is of practical utility to know what influences their action. 405. _The function of these vessels is increased by moisture, and lessened by an active state of the lacteals._ Observation shows that the ill-fed, and those persons that live in marshy districts, contract contagious diseases more readily than those individuals who are well fed, and breathe a dry and pure air. 406. _The air of the sick-room should be dry._ If due attention is not given to ventilation, the clothing of the nurse and patient, together with the air of the room, will be moistened by the exhalations from the skin and lungs. This exhalation may contain a poison of greater or less power, according to its quantity and degree of concentration, and may be absorbed and reconveyed into the system, causing inflammatory diseases, and not unfrequently death. _Observations._ 1st. When we are attending a sick person a current of air that has passed over the patient should be avoided. We may approach with safety very near a person who has an infectious disease, provided care is taken to keep on the side from which the currents of air are admitted into the room. 2d. When we have been visiting or attending on a sick person, it is judicious to change the apparel worn in the sick-room, and also give the skin a thorough bathing. The outside garments, also, should be aired, as poisonous matter may have penetrated the meshes of the clothing. -=-=-=-=-=-=-=-=-=-=-=-= 404-413. _Give the hygiene of the lymphatic vessels._ 404. What is said respecting the action of the lymphatic vessels? 405. What influences the function of these vessels? What does observation show? 406. Why should the air of the sick-room be dry? What suggestion when we have been visiting or attending on the sick? -=-=-=-=-=-=-=-=-=-=-=-= 407. _The stomach should be supplied with food of a nutrient and digestible character, in proper quantities, and at stated periods._ The chyle formed from the food stimulates the lacteals to activity, which activity is attended with an inactive state of the lymphatics of the skin and lungs. Thus due attention should be given to the food of the attendants on the sick, and the members of the family. Before visiting a sick person it is judicious to take a moderate amount of nutritious food. _Observation._ Many individuals, to prevent contracting disease that may be communicated from one person to another, use tobacco, either chewed or smoked; and sometimes alcohol, with decoctions of bitter herbs. These substances do not diminish, but tend to increase, the activity of the lymphatics. Thus they make use of the means by which the poisonous matter formed in the system of the diseased person, may be more readily conveyed into their own. 408. _The skin and clothing, as well as the bed-linen, should be frequently cleansed._ This will remove the poisonous matter that may be deposited upon the skin and garments, which, if suffered to remain, might be conveyed into the system by the action of the lymphatics. This points also to a frequent change of the wearing apparel, as well as the coverings of the bed. In visiting the unhealthy districts of the South and West, the liability of contracting disease is much lessened by taking a supply of food at proper periods, keeping the skin and clothing in a clean state, the room well ventilated, and avoiding the damp chills of evening. 409. _Absorption by the skin is most vigorous when the cuticle is removed by vesication, or blistering._ Then external applications are brought into immediate contact with the orifices of the lymphatics of the skin, and by them rapidly imbibed and circulated through the system. Thus arsenic applied to the cutaneous vessels, and strong solutions of opium to extensive burns, have been absorbed in quantities sufficient to poison the patient. -=-=-=-=-=-=-=-=-=-=-=-= 407. Why should the stomach be supplied with food of a nutrient and digestible character? What is said of the use of alcohol, or tobacco, in preventing the introduction of the poisonous matter of contagious diseases? 408. Why should the clothing and bed-linen be frequently washed? What suggestion to persons in visiting the unhealthy districts of the South and West? 409. When is cutaneous absorption most vigorous? Why? -=-=-=-=-=-=-=-=-=-=-=-= 410. _When the cuticle is only punctured or abraded, poisonous matter may be introduced into the system._ The highly respected Dr. W., of Boston, lost his life by poisonous matter from the body of a patient subjected to a post mortem examination. He had removed from his finger, previous to the examination, a "hang-nail," and the poison from the dead body was brought in contact with the denuded part, and through the agency of the lymphatics it was conveyed into the system. 411. Puncture any part of the cuticle with the finest instrument that has upon its point the smallest conceivable quantity of the _vaccine virus_, or small-pox matter, and it will be brought into contact with the lymphatic vessels, and through their agency conveyed into the system. The result is, that persons thus operated upon have the small-pox, or the vaccine disease. 412. When we expose ourselves to any poisonous vapors, or handle diseased animals or sick persons, safety and health require that the cuticle be not broken or otherwise injured. In many instances, the poisonous animal matter upon hides has been introduced into the systems of tanners, through small ulcers upon their fingers or hands. From these sores there would be seen small red lines extending up the arm. These swelled tracts indicate an inflammation of the large lymphatic trunks, that have been irritated and diseased by the passage of poisonous matter through them into the system. -=-=-=-=-=-=-=-=-=-=-=-= 410. Do the same results follow, if the cuticle is only punctured? Relate an instance of death by the absorption of poisonous matter. 411. By what means is the vaccine matter introduced into the system? 412. What caution is necessary when we expose ourselves to poisonous vapors? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ A distressing illustration of the absorption of deleterious substances from the surface of a sore, is seen in the favorite experiments of that class of "quacks," who style themselves "cancer doctors." With them, every trifling and temporary enlargement, or tumor, is a cancer. Their general remedy is arsenic; and happy is the unfortunate sufferer who escapes destruction in their hands, for too frequently their speedy cure is death. 413. In case of an accidental wound, it is best immediately to bathe the part thoroughly in pure water, and to avoid all irritating applications. In some instances, it would be well to apply _lunar caustic_ immediately. When handling or shrouding dead bodies, or removing the skin from animals that have died of disease, it would be well to lubricate the hands with olive-oil or lard. This affords protection to the minute portions of the skin, from which the cuticle may be removed. In all cases where there is an ulcer or sore, the part should be covered with something impervious to fluids, as court-plaster, before exposing the system to any animal, vegetable, or mineral poison. -=-=-=-=-=-=-=-=-=-=-=-= 413. What direction is given when the cuticle is broken? What suggestion is given when shrouding dead bodies? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXI. SECRETION. 414. In the human body are found many fluids and solids of dissimilar appearance and character. These are produced by the action of organs, some of which are of simple structure, while others are very complicated in their arrangement. These organs are called _Se-cre´to-ry_. ANATOMY OF THE SECRETORY ORGANS. 415. The SECRETORY ORGANS are the _Ex-ha´lants_, _Fol´li-cles_, and the _Glands_. 416. The EXHALANTS were supposed to be terminations of arteries or capillaries. The external exhalants terminate on the skin and mucous membranes; the internal in the cellular and medullary tissues. (Appendix I.) [Illustration: Fig. 86. A secretory follicle. An artery is seen, which supplies the material for its secretion. Follicles are also supplied with veins and organic nerves.] 417. The FOLLICLES are small bags, or sacs, situated in the true skin, and mucous membrane. The pores seen on the skin are the outlets of these bodies. -=-=-=-=-=-=-=-=-=-=-=-= 414. How are the fluids and solids of the body produced? 415-419. _Give the anatomy of the secretory organs._ 415. Name the secretory organs. 416. Describe the exhalants. What is represented by fig. 86? 417. Define follicles. -=-=-=-=-=-=-=-=-=-=-=-= 418. The GLANDS are soft, fleshy organs, and as various in their structure, as the secretions which it is their function to produce. Each gland is composed of many small lobules united in a compact mass, and each lobule communicates by a small duct with the principal outlet, or duct of the organ. Every gland is supplied with arteries, veins, lymphatics, and nerves. These, with the ducts, are arranged in a peculiar manner, and connected by cellular membrane. 419. There are two classes of glands, one for the modification of the fluids which pass through them, as the mesenteric and lymphatic glands; and the other for the secretion of fluids which are either useful in the animal economy, or require to be rejected from the body. [Illustration: Fig. 87. 1, 1, A secretory gland. 2, 2, Minute ducts that are spread through the glands. These coalesce to form the main duct, 3.] PHYSIOLOGY OF THE SECRETORY ORGANS. 420. SECRETION is one of the most obscure and mysterious functions of the animal economy. "It is that process by which various substances are separated from the blood, either with or without experiencing any change during their separation." Not only is the process by which substances are separated from the blood, called secretion, but the same term is also applied to substances thus separated. Thus physiologists say, that by the process of secretion, bile is formed by the liver; and also, that bile is the secretion of this organ. -=-=-=-=-=-=-=-=-=-=-=-= 418. Give the structure of the glands. 419. How are the glands arranged? 420-431. _Give the physiology of the secretory organs._ 420. What is secretion? -=-=-=-=-=-=-=-=-=-=-=-= 421. The secreted fluids do not exist in that form in the blood, but most of the elements of which they are made do exist in this fluid, and the "vessels by which it is accomplished may well be called the architects and chemists of the system; for out of the same material--the blood--they construct a variety of wonderful fabrics and chemical compounds. We see the same wonderful power possessed, also, by vegetables; for out of the same materials the olive prepares its oil, the cocoa-nut its milk, the cane its sugar, the poppy its narcotic, the oak its green pulpy leaves, and its dense woody fibre. All are composed of the same few, simple elements, arranged in different order and proportions." 422. "In like manner we find the vessels, in animated bodies, capable of forming all the various textures and substances which compose the frame; the cellular tissue, the membranes, the ligaments, the cartilages, the bones, the marrow, the muscles with their tendons, the lubricating fluid of the joints, the pulp of the brain, the transparent jelly of the eye; in short, all the textures of the various organs of which the body is composed, consist of similar ultimate elements, and are manufactured from the blood." 423. Of the agents that produce or direct the different secretions, we have no very accurate knowledge. Some have supposed this function to be mechanical, others a chemical process, but experiments prove that it is dependent on nervous influence. If the nerves are divided which are distributed to any organ, the process of secretion is suspended. It is no uncommon occurrence, that the nature of milk will be so changed from the influence of anger in the mother, as to cause vomiting, colic, and even convulsions, in the infant that swallows it. Unexpected intelligence either of a pleasant or unpleasant character, by its influence on the nervous system, will frequently destroy the appetite. Sometimes mental agitation, as fear, will cause a cold sweat to pervade the surface of the body. -=-=-=-=-=-=-=-=-=-=-=-= 421. What is said respecting secreted substances? Do vegetables possess the property of secretion? 422. From what are the various textures formed? 423. Have we accurate knowledge of the agents that produce secretion? -=-=-=-=-=-=-=-=-=-=-=-= 424. Secretions are constantly maintained, during life, from the serous membrane, by the action of the internal exhalants. The fluid which is exhaled bears some resemblance to the serum of the blood. Its use is to furnish the organs, which are surrounded by this membrane, with a proper degree of moisture, and thus enables them to move easily on each other, as those within the chest and abdomen. 425. The cellular tissue exhales a serous fluid, and when it becomes excessive in quantity, general dropsy is produced. Fat is another secretion, which is thrown out, in a fluid state, from the cellular membrane. It is deposited in little cells, and exists in the greatest abundance between the skin and the muscles. Its use seems to be, to form a cushion around the body for its protection; to furnish nutriment for the system when food cannot be taken; to supply the carbon and hydrogen necessary to sustain the generation of heat, when these articles of combustion are not otherwise furnished. The _med´ul-la-ry_ substance, (marrow,) in the cavities of the long bones, is very much like fat. _Observation._ During sickness, if there is not emaciation or absorption of this secretion, it is considered an unfavorable symptom, because it indicates a want of power in the absorbing system, which is among the last to be affected. -=-=-=-=-=-=-=-=-=-=-=-= How is it proved that secretion depends on nervous influence? 424. What is said of the secretions from the serous membrane? 425. From what tissue is a serous fluid exhaled? What is the effect when this fluid becomes excessive in quantity? What is fat? Its use? What is marrow? -=-=-=-=-=-=-=-=-=-=-=-= 426. The mucous secretion is a transparent, viscid fluid which is secreted by those membranes that line the cavities of the body, which have an external communication, as the trachea and alimentary canal. This secretion serves to protect these parts from the influence of the air, and concurs, by means of its peculiar properties, in the performance of their functions. 427. There are two external secretions, namely, one from the skin, called perspiration, and the other from the lungs. The cutaneous exhalation, or transpiration[14] exists in two forms, called sensible perspiration (sweat) and insensible perspiration. The pulmonary exhalation is the most important and universal, and closely resembles that of the skin. [14] _Transpiration_ is a term often used generically, to signify the passage of fluids or gases through membranes, internally or externally; but _perspiration_ is a specific term, signifying transpiration on to the external surface. 428. The follicles are found only in the skin and mucous membrane. They secrete an oily, unctuous substance, which mixes with the transpiration, and lubricates the skin. At the root of each hair there is a minute follicle, which secretes the fluid that oils the hair. The wax in the passage of the ear is secreted from these bodies. 429. All the blood distributed to the different glands is similar in composition and character; but the fluids secreted by them, vary in appearance in a remarkable degree. The office of the glands appears to be principally to form different secretions. Thus the salivary glands secrete the insipid saliva; the lachrymal glands, the saline tears; the liver, the yellow, ropy bile; and the kidneys, the acrid urine. -=-=-=-=-=-=-=-=-=-=-=-= 426. What is said relative to the mucous secretion? 427. Name the external secretions. 428. Give the office of the follicles. 429. What appears to be the principal office of the glands? 430. Mention a secretion produced in a particular emergency. -=-=-=-=-=-=-=-=-=-=-=-= 430. Some secretions are evidently produced only in particular emergencies, as is seen in the increased secretion of bony matter when a limb is broken. 431. When any substance which is not demanded for nutrition, or does not give nourishment to the system, is imbibed by the lymphatic vessels, and conveyed into the blood, it is eliminated in the secretions. _Illustration._ A few years since, a poor inebriate was carried to a London hospital in a state of intoxication. He lived but a few hours. On examining his brain, nearly half a gill of fluid, strongly impregnated with gin, was found in the cavities of this organ. This was secreted from the vessels of the brain. HYGIENE OF THE SECRETORY ORGANS. 432. _Unless the secretions are regularly maintained, disease will be the ultimate result._ Let the secretions from the skin be suppressed, and fever or some internal inflammation will follow. If the bile is impeded, digestion will be impaired. If any other secretion is suppressed, it will cause a derangement of the various internal organs. _Observation._ Ardent spirits derange the secretions, and change the structure of the brain. This is one reason why inebriates do not generally live to advanced age. 433. _The quantity of blood influences the character of the secretions._ If it is lessened to any great extent, the secretions will be lessened as well as changed in character. _Illustration._ When a person has lost a considerable quantity of blood, there is a sensation of thirst in the fauces, attended with a cold, pale, dry skin. When reaction comes on, the perspiration is cold, attended with nausea, and sometimes vomiting. -=-=-=-=-=-=-=-=-=-=-=-= 431. What becomes of those substances imbibed by the lymphatics that do not give nourishment to the body. 432-437. _Give the hygiene of the secretory organs._ 432. What effect on the system when the secretions are not regularly maintained? 433. Does the quantity of blood influence the secretions? Give an illustration. -=-=-=-=-=-=-=-=-=-=-=-= 434. _The secretory organs require the stimulus of pure blood._ If this fluid is vitiated, the action of the secretory organs will be more or less modified. Either the quantity will be affected or the quality will be altered. _Observation._ The impurity of the blood arising from the inhalation of the vitiated air of sleeping rooms, diminishes and changes the character of the secretions of the mouth and stomach. This accounts for the thirst, coated tongue, and disagreeable taste of the mouth when impure air is breathed during sleep. The disease it induces, is indigestion or dyspepsia. 435. _The amount of action modifies the condition of the secretory organs._ When a secretory organ is excessively stimulated, its vigor and energy are reduced. The subsequent debility may be so great as to suppress or destroy its functional power. _Illustrations._ 1st. In those sections of the country where flax is spun on a "foot-wheel," it is not unfrequent that the spinners moisten the thread with the secretions of the mouth. This seems to operate economically for a time, but debility of the salivary organs soon follows, which incapacitates them from supplying saliva sufficient to moisten the food, producing in a short time disease of the digestive organs. 2d. The habit of continual spitting, which attends the chewing of tobacco and gums, and other substances, between meals, induces debility, not only of the salivary glands, but of the system generally. 436. _One secretory organ may do the office of another._ This increased action of a secretory organ may be sustained for a limited time without permanent injury, but, if long continued, a diseased action of the organ will follow. Of morbid secretions we have examples in the ossification of the valves of the heart, cancerous and other tumors. -=-=-=-=-=-=-=-=-=-=-=-= 434. What is the effect of impure blood on the secretory organs? 435. What results from stimulating excessively a secretory organ? How is this illustrated? 436. What is the effect when one secretory organ performs the office of another? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ In the evenings of the warm season, a chill upon the impressible skin, that suppresses the perspiration, is frequently followed by a diarrhoea, dysentery, or cholera morbus. These can be prevented by avoiding the chill. An efficient means of relief, is immediately to restore the skin to its proper action. 437. _The secretions are much influenced by the mind._ How this is effected, it is difficult to explain; but many facts corroborate it. Every one has felt an increased action of the tear-glands from distressing feelings. Cheerfulness of disposition and serenity of the passions are peculiarly favorable to the proper performance of the secretory function. From this we may learn how important it is to avoid such things as distract, agitate, or harass us. _Observation._ In fevers and other diseases, when the skin, mouth, and throat are dry from a suppression of the secretions, let the mind of the patient be changed from despondency to hope, and the skin and the membrane that lines the mouth and throat will exhibit a more moist condition, together with a general improvement of the vital organs of the system. Consequently, all just encouragement of the restoration to health should be given to a sick person. -=-=-=-=-=-=-=-=-=-=-=-= Give examples of morbid secretions. What is one cause of dysentery and cholera morbus? How can these affections he relieved? 437. Show the influence of the mind on the secretions. Mention instances of its influence. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXII. NUTRITION. 438. NUTRITION is the vital act by which the different parts of the body renew the materials of which they are composed. Digestion, circulation, absorption, and respiration, are but separate links in the chain of nutrition, which would be destroyed by the absence of any one of them. 439. The nutritive process is also a kind of secretion, by which particles of matter are separated from the blood and conveyed with wonderful accuracy to the appropriate textures. The function of the nutrient vessels antagonizes those of absorption: while one system is constructing, with beautiful precision, the animal frame, the other is diligently employed in pulling down this complicated structure. 440. This ever-changing state of the body is shown by giving animals colored matter, mixed with their food, which in a short time tinges their bones with the same color as the matter introduced. Let it be withdrawn, and in a few days the bones will assume their former color--evidently from the effects of absorption. The changeful state of the body is further shown by the losses to which it is subjected; by the necessity of aliment; by the emaciation which follows abstinence from food. -=-=-=-=-=-=-=-=-=-=-=-= 438-454. _What remarks respecting nutrition?_ 438. What is nutrition? 439. What is said of the nutritive process? The function of the nutrient vessels? 440. Give a proof of the ever-changing state of the body. Give other instances illustrative of the changeful state of the body. -=-=-=-=-=-=-=-=-=-=-=-= 441. Every part of the body is subject to this continual change of material, yet it is effected with such regularity, that the size, shape, and appearance, of every organ is preserved; and after an interval of a few years, there may not remain a particle of matter which existed in the system at a former period. Notwithstanding this entire change, the personal identity is never lost. 442. Many calculations have been made to determine in what length of time the whole body is renewed. Some have supposed that it is accomplished in four years; others have fixed the period at seven years; but the time of the change is not definite, as was supposed by a genuine son of the Emerald Isle, who had been in America _seven years and three months_, and consequently maintained that he was a native American. _Observation._ India ink, when introduced into the skin, is not removed; hence some assert that this tissue is an exception to the alternate deposition and removal of its atoms. The ink remains because its particles are too large to be absorbed, and when in the skin it is insoluble. 443. "Those animals which are most complicated in their structure, and are distinguished by the greatest variety of vital manifestations, are subject to the most rapid changes of matter. Such animals require more frequent and more abundant supplies of food; and, in proportion as they are exposed to the greater number of external impressions, will be the rapidity of this change of matter." 444. "Animals may be situated so that they lose nothing by secretion; consequently, they will require no nutriment. Frogs have been taken from fissures in solid lime rock, which were imbedded many feet below the surface of the earth, and, on being exposed to the air, exhibited signs of life." -=-=-=-=-=-=-=-=-=-=-=-= 441. Why is the personal identity never lost in the change of materials, which is unceasing in the system? 442. Give the opinion of physiologists respecting the time required for the renewal of the whole body. What exception to the changing state Of the different textures? 443. What animals are subject to the most rapid changes of material? 444. May animals be situated so that they require no nutriment? What is related of frogs? -=-=-=-=-=-=-=-=-=-=-=-= 445. The renovation of the bone, muscle, ligament, tendon, cartilage, fat, nerve, hair, &c., is not perfected merely by the general circulation of the fluid which is expelled from the left side of the heart, but through the agency of a system of minute vessels, which, under ordinary circumstances, cannot be seen by the eye, even when aided by the microscope; still, minute as they are, the function of these agents is necessary to the continuance of life. They are the smallest capillary vessels. 446. "As the blood goes the round of the circulation, the nutrient capillary vessels select and secrete those parts which are similar to the nature of the structure, and the other portions pass on; so that every tissue imbibes and converts to its own use the very principles which it requires for its growth; or, in other words, as the vital current approaches each organ, the particles appropriate to it feel its attractive force,--obey it,--quit the stream,--mingle with the substance of its tissue,--and are changed into its own true and proper nature." 447. Thus, if a bone is broken, a muscle or a nerve wounded, and, if the system is in a proper state of health, the vital economy immediately sets about healing the rupture. The blood, which flows from the wounded vessels, coagulates in the incision, for the double purpose of stanching the wound, and of forming a matrix for the regeneration of the parts. Very soon, minute vessels shoot out from the living parts into the coagulum of the blood, and immediately commence their operations, and deposit bony matter, where it is required to unite fractured bones, and nervous substance to heal the wounded nerve, &c. -=-=-=-=-=-=-=-=-=-=-=-= 445. Show how the renovation of the bones, muscles, &c., is perfected. 446. What is said of the office of the nutrient capillary vessels? 447. When a bone is fractured, by what process is it healed? -=-=-=-=-=-=-=-=-=-=-=-= 448. But the vital economy seems not to possess the power of reproducing the muscles and true skin, and therefore, when these parts are wounded, the rupture is repaired by a gelatinous substance, which gradually becomes hard, and sometimes assumes something of a fibrous appearance. It so perfectly unites the divided muscle, however, as to restore its functional power. When the cuticle is removed, it is reproduced and no scar remains; but, when the true skin is destroyed, a scar is formed. 449. It is not uncommon that the nutrient arteries have their action so much increased in some parts, as to produce preternatural growth. Sometimes the vessels whose function it is to deposit fat, are increased in action, and wens of no inferior size are formed. Again, there may be a deposition of substances unlike any known to exist in the body. Occasionally, these nutrient arteries of a part take on a new action, and not only deposit their ordinary substance, but others, which they have not heretofore secreted, but which are formed by vessels of other parts of the body. It is in this way that we account for the bony matter deposited in the valves of the heart and brain, also the chalky deposits around the finger-joints. 450. In infancy and childhood, the function of nutrition is very active; a large amount of food is taken, to supply the place of what is lost by the action of the absorbents, and also to contribute to the growth of the body. In middle age, nutrition and absorption are more equal; but in old age, the absorbents are more active than the nutrient vessels. The size, consequently, diminishes, the parts become weaker, the bones more brittle, the body bends forward, and every function exhibits marks of decay and dissolution. 451. A striking instance of active absorption in middle age was exhibited in the person of Calvin Edson, of Vermont, who was exhibited in the large towns of New England, as the "living skeleton." In early manhood he was athletic, and weighed one hundred and sixty pounds; but the excessive action of the absorbents over the nutrient vessels, reduced his weight, in the interval of eighteen years, to sixty pounds. -=-=-=-=-=-=-=-=-=-=-=-= 448. What occurs when a muscle is divided? 449. State some of the results of an increased action of the nutrient arteries. 450. When is nutrition most active? How in middle age? How in old age? 451. Relate a striking instance of active absorption in middle age. -=-=-=-=-=-=-=-=-=-=-=-= 452. Instances, on the other hand, have occurred, of the action of the nutrient vessels exceeding, in an extreme degree, those of absorption; as in the person of a colored girl, thirteen years of age, who was exhibited in New York in the summer of 1840. She was of the height of misses at that age, but weighed five hundred pounds. Several cases are on record of persons weighing eight hundred pounds. 453. As already mentioned, the blood is the nutritive fluid of animals. When this fluid is coagulated, a thick, jelly-like mass floats in the serum, called coagulum. This coagulated mass is composed of fibrin, and red globulated matter. The color of the red globules is owing to the presence of iron, though some physiologists think it depends on an animal substance of a gelatinous character. _Observation._ That portion of the serum which remains fluid after coagulation by heat has taken place, is called _se-ros´i-ty_. It is more abundant in the blood of old, than in that of young animals; and it forms the "red gravy" in roasted meats. 454. The blood is not necessarily red. It may be white, as in most fish. There is no animal in which the blood is equally red in all parts of the body. The ligaments, tendons, and other white tissues in man are supplied but sparingly with red blood. The fluid that supplies these tissues is whitish. -=-=-=-=-=-=-=-=-=-=-=-= 452. Of excessive nutrition in early life. 453. Describe the parts that enter into the composition of the blood. What part of the blood forms the red gravy in roasted meats? 454. Is the blood necessarily red? Of what color is the blood of the fish? What part of the human system has white blood? -=-=-=-=-=-=-=-=-=-=-=-= HYGIENE OF NUTRITION. 455. _Healthy nutrition requires pure blood._ If the nutrient arteries of the bones are supplied with impure blood, they will become soft or brittle, their vitality will be impaired, and disease will be the ultimate result. The five hundred muscles receive another portion of the blood. These organs are attached to, and act upon the bones. Upon the health and contractile energy of the muscles depends the ability to labor. Give these organs of motion impure blood, which is an unhealthy stimulus, and they will become enfeebled, the step will lose its elasticity, the movement of the arm will be inefficient, and every muscle will be incapacitated to perform its usual amount of labor. 456. When the stomach, liver, and other organs subservient to the digestion of food, are supplied with impure blood, the digestive process is impaired, causing faintness and loss of appetite, also a deranged state of the intestines, and, in general, all the symptoms of dyspepsia. 457. The delicate structure of the lungs, in which the blood is or should be purified, needs the requisite amount of pure blood to give them vigor and health. When the blood is not of this character, the lungs themselves lose their tone, and, even if permitted to expand freely, have not power fully to change the impure quality of this circulating fluid. 458. The health and beauty of the skin require that the blood should be well purified; but, if the arteries of the skin receive vitiated blood, pimples and blotches appear, and the individual suffers from "humors." Drinks, made of various kinds of herbs, as well as pills and powders, are taken for this affection. These will never have the desired effect, while the causes of impure blood exist. -=-=-=-=-=-=-=-=-=-=-=-= 455-462. _Give the hygiene of nutrition._ 455. What is the effect of impure blood upon the bones? On the muscles? 456. On the digestive organs? 457. On the lungs? 458. What is the effect if the vessels of the skin are supplied with vitiated blood? -=-=-=-=-=-=-=-=-=-=-=-= 459. If the nutrient arteries convey impure material to the brain, the nervous and bilious headache, confusion of ideas, loss of memory, impaired intellect, dimness of vision, and dulness of hearing, will be experienced; and in process of time, the brain becomes disorganized, and the brittle thread of life is broken. _Observations._ 1st. An exertion of any organ beyond its powers, induces weakness that will disturb the nutrition of the part that is called into action; and it recovers its energy more slowly in proportion to the excess of the exertion. The function of the organ may be totally and permanently destroyed, if the exertion is extremely violent. We sometimes see palsy produced in a muscle simply by the effort to raise too great a weight. The sight is impaired, and total blindness may be produced, by exposure to light too strong or too constant. The mind may be deranged, or idiocy may follow the excess of study or the over-tasking of the brain. 2d. When the function of an organ is permanently impaired or destroyed by over-exertion, the nutrition of the part is rendered insufficient, or is entirely arrested; and then the absorbents remove it wholly or partially, as they do every thing that is no longer useful. Thus, in palsied patients, a few years after the attack, we often find scarce any trace of the palsied muscles remaining; they are reduced almost to simple cellular tissue. The condition of the calf of the leg, in a person having a club-foot, is a familiar proof of this. 460. _The blood may be made impure, by the chyle being deficient in quantity or defective in quality._ This state of the chyle may be produced by the food being improper in quantity or quality, or by its being taken in an improper manner, at an improper time, and when the system is not prepared for it. The remedy for impure blood produced in any of these ways is to correct the injudicious method of using food. (See Chapters XV. and XVI.) -=-=-=-=-=-=-=-=-=-=-=-= 459. How does impure blood affect the brain? What is the effect when any organ is exerted beyond its powers? What is the effect when an organ is permanently impaired? 460. How may the blood become impure? -=-=-=-=-=-=-=-=-=-=-=-= 461. _The blood may also be rendered impure, by not supplying it with oxygen in the lungs, and by the carbon not being eliminated from the system through this channel._ The remedy for "impurities of the blood," produced in this manner, would be, to carefully reduce to practice the directions in the chapters on the hygiene of the respiratory organs, relative to the free movements of the ribs and diaphragm, and the proper ventilation of rooms. 462. _A retention of the waste products of the skin produces impure blood._ When the vessels of the skin, by which the waste, useless material is eliminated from the system, have become inactive by improper and inadequate clothing, or by a want of cleanliness, the dead, injurious atoms of matter are retained in the circulatory vessels. The only successful method of purifying the blood and restoring health when this condition exists, is to observe the directions given relative to clothing and bathing. (See Chapters XXXIII. and XXXIV.) _Observation._ If the blood has become "impure," or "loaded with humors," (an idea generally prevalent,) it is not and cannot be "purified" by taking patent pills, powders, drops, &c. But, on the contrary, by observing the suggestions in the preceding paragraphs, the blood can be freed of its impurities, and, what is of greater importance, such "injurious humors" will be prevented. -=-=-=-=-=-=-=-=-=-=-=-= 461. Mention another means by which the blood may be made impure. How remedied? 462. What is the effect of want of cleanliness upon the blood? What is said respecting "humors" in the blood? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 88. A front view of the organs within the chest and abdomen. 1, 1, 1, 1, The muscles of the chest. 2, 2, 2, 2, The ribs. 3, 3, 3, The upper, middle, and lower lobes of the right lung. 4, 4, The lobes of the left lung. 5, The right ventricle of the heart. 6, The left ventricle. 7, The right auricle of the heart. 8, The left auricle. 9, The pulmonary artery. 10, The aorta. 11, The vena cava descendens. 12, The trachea. 13, The oesophagus. 14, 14, 14, 14, The pleura. 15, 15, 15, The diaphragm. 16, 16, The right and left lobe of the liver. 17, The gall-cyst. 18, The stomach. 26, The spleen. 19, 19, The duodenum. 20, The ascending colon. 21, The transverse colon. 25, The descending colon. 22, 22, 22, 22, The small intestine. 23, 23, The abdominal walls turned down. 24, The thoracic duct, opening into the left subclavian vein, (27.)] CHAPTER XXIII. THE RESPIRATORY ORGANS. 463. The nutrient portion of the food is poured into the left subclavian vein, (24, 27, fig. 88,) at the lower part of the neck, and is carried to the right cavities of the heart. The fluid in these cavities consists of the chyle incorporated with the impure blood. Neither of these two elements is fitted to promote the growth or repair the waste of the body. They must be subjected to a process, by which the first can be converted into blood, and the second freed of its carbonic acid gas and water. This is effected by the _Respiratory Organs_. ANATOMY OF THE RESPIRATORY ORGANS. 464. The RESPIRATORY ORGANS are the _Lungs_, (lights,) the _Tra´che-a_, (windpipe,) the _Bronch´i-a_, (subdivisions of the trachea,) and the _Air-Ves´i-cles_, (air-cells at the extremities of the bronchia.) The _Di´a-phragm_, (midriff,) _Ribs_, and several _Muscles_, also aid in the respiratory process. 465. The LUNGS are conical organs, one on each side of the chest, embracing the heart, (fig. 88,) and separated from each other by a membranous partition. The color of the lungs is a pinkish gray, mottled, and variously marked with black. Each lung is divided into lobes, by a long and deep fissure, which extends from the posterior surface of the upper part of the organ, downward and forward, nearly to the anterior angle of the base. In the right lung, the upper lobe is subdivided by a second fissure. This lung is larger and shorter than the left. It has three lobes, while the left has only two. -=-=-=-=-=-=-=-=-=-=-=-= 463. What fluids are conveyed into the right cavities of the heart? What is necessary before they can be adapted to the wants of the body? By what organs are these changes effected? 464-474. _Give the anatomy of the respiratory organs._ 464. Name the respiratory organs. What organs also aid in the respiratory process? 465. Describe the lungs. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 89. A back view of the heart and lungs. The posterior walls of the chest are removed. 1, 2, 3, The upper, middle, and lower lobes of the right lung. 8, 9, 10, The two lobes of the left lung. 6, 13, The diaphragm. 7, 7, 14, 14, The pleura that lines the ribs. 4, 11, The pleura that lines the mediastine. 5, 12, 12, The portion of the pleura that covers the diaphragm. 15, The trachea, 16, The larynx. 19, 19, The right and left bronchia. 20, The heart. 29, The lower part of the spinal column.] -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 89. -=-=-=-=-=-=-=-=-=-=-=-= 466. Each lung is enclosed, and its structure maintained by a serous membrane, called the _pleu´ra_, which invests it as far as the root, and is thence reflected upon the walls of the chest. The lungs, however, are on the outside of the pleura, in the same way as the head is on the outside of a cap doubled upon itself. The reflected pleuræ in the middle of the thorax form a partition, which divides the chest into two cavities. This partition is called the _me-di-as-ti´num_. [Illustration: Fig. 90. The heart and lungs removed from the chest, and the lungs freed from all other attachments. 1, The right auricle of the heart. 2, The superior vena cava. 3, The inferior vena cava. 4, The right ventricle. 5, The pulmonary artery issuing from it. _a_, _a_, The pulmonary artery, (right and left,) entering the lungs. _b_, _b_, Bronchia, or air-tubes, entering the lungs. _v_, _v_, Pulmonary veins, issuing from the lungs. 6, The left auricle. 7, The left ventricle. 8, The aorta. 9, The upper lobe of the left lung. 10, Its lower lobe. 11, The upper lobe of the right lung. 12, The middle lobe. 13, The lower lobe.] _Observation._ When this membrane that covers the lungs, and also lines the chest, is inflamed, the disease is called "pleurisy." -=-=-=-=-=-=-=-=-=-=-=-= 466. By what are the lungs enclosed? What is the relative position of the lungs and pleura? What is said of the reflected pleuræ? Explain fig. 90. What part of the lungs is affected in pleurisy? -=-=-=-=-=-=-=-=-=-=-=-= 467. The lungs are composed of the ramifications of the bronchial tubes, which terminate in the bronchial cells, (_air-cells_,) lymphatics, and the divisions of the pulmonary artery and veins. All of these are connected by cellular tissue, which constitutes the _pa-ren´chy-ma_. Each lung is retained in its place by its _root_, which is formed by the pulmonary arteries, pulmonary veins, and bronchial tubes, together with the bronchial vessels and pulmonary nerves. 468. The TRACHEA extends from the larynx, of which it is a continuation, to the third dorsal vertebra, where it divides into two parts, called bronchia. It lies anterior to the spinal column, from which it is separated by the oesophagus. 469. The BRONCHIA proceed from the bifurcation, or division of the trachea, to their corresponding lungs. Upon entering the lungs, they divide into two branches, and each branch divides and subdivides, and ultimately terminates in small sacs, or cells, of various sizes, from the twentieth to the hundredth of an inch in diameter. So numerous are these bronchial or air-cells, that the aggregate extent of their lining membrane in man has been computed to exceed a surface of 20,000 square inches, and Munro states that it is thirty times the surface of the human body. _Illustration._ The trachea may be compared to the trunk of a tree; the bronchia, to two large branches; the subdivisions of the bronchia, to the branchlets and twigs; the air-cells, to the buds seen on the twigs in the spring. 470. The AIR-VESICLES and small bronchial tubes compose the largest portions of the lungs. These, when once inflated, contain air, under all circumstances, which renders their specific gravity much less than water; hence the vulgar term, _lights_, for these organs. The trachea and bronchial tubes are lined by mucous membrane. The structure of this membrane is such, that it will bear the presence of pure air without detriment, but not of other substances. -=-=-=-=-=-=-=-=-=-=-=-= 467. Of what are the lungs composed? How retained in place? 468. Where is the trachea situated? 469. Describe the bronchia. What is the aggregate extent of the lining membrane of the air-cells? To what may the trachea and its branches be compared? 470. What is said of the air-cells and bronchial tubes? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 91. A representation of the larynx, trachea, bronchia, and air-cells. 1, 1, 1, An outline of the right lung. 2, 2, 2, An outline of the left lung. 3, The larynx 4, The trachea. 5, The right bronchial tube. 6, The left bronchial tube. 7, 7, 7, 8, 8, 8, The subdivisions of the right and left bronchial tubes. 9, 9, 9, 9, 9, 9, Air-cells.] -=-=-=-=-=-=-=-=-=-=-=-= What membrane lines the trachea and its branches? What is peculiar in its structure? What does fig. 91 represent? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ The structure of the trachea and lungs may be illustrated, by taking these parts of a calf or sheep and inflating the air-vesicles by forcing air into the windpipe with a pipe or quill. The internal structure may then be seen by opening the different parts. 471. The lungs, like other portions of the system, are supplied with nutrient arteries and nerves. The nervous filaments that are distributed to these organs are in part from the tenth pair, (par vagum,) that originates in the brain, and in part from the sympathetic nerve. The muscles that elevate the ribs and the diaphragm receive nervous fibres from a separate system, which is called the respiratory. [Illustration: Fig. 92. 1, A bronchial tube. 2, 2, 2, Air-vesicles. Both the tube and vesicles are much magnified. 3, A bronchial tube and vesicles laid open.] _Observation._ When the mucous membrane of a few of the larger branches of the windpipe is slightly inflamed, it is called a "cold;" when the inflammation is greater, and extends to the lesser air-tubes, it is called _bronch-i´tis_. When the air-cells and parenchyma become inflamed, it is called inflammation of the lungs. Coughing is a violent expulsory effort by which air is suddenly forced through the bronchia and trachea to remove offending matter. -=-=-=-=-=-=-=-=-=-=-=-= How may the structure of the trachea and its branches be illustrated? 471. Are the lungs supplied with nutrient arteries? Where are the respiratory nerves distributed? From what source do these organs derive their nervous filaments? -=-=-=-=-=-=-=-=-=-=-=-= 472. The RIBS are joined to the spinal column at their posterior extremity; and in front, they terminate in cartilages, which unite them to the sternum. They incline downward, from the spinal column to the breast-bone, and form resisting walls that assist in producing the partial vacuum necessary for inspiration. [Illustration: Fig. 93. A section of the chest when the lungs are inflated. 1, The diaphragm. 2, The muscular walls of the abdomen.] [Illustration: Fig. 94. A section of the chest when the lungs are contracted. 1, The diaphragm in common expiration. 2, 2, The muscular walls of the abdomen. 3, The position of the diaphragm in forced expiration.] These engravings show the diaphragm to be more convex, and the walls of the abdomen more flattened, when the lungs are collapsed, than when they are inflated. 473. The DIAPHRAGM is a flexible circular partition, that separates the respiratory from the digestive organs, and the chest from the abdomen. Its margin is attached to the spinal column, the sternum, and cartilages of the lower ribs. The lungs rest upon its upper surface, while the liver and stomach are placed below it, (fig. 88.) In a state of repose, its upper surface forms an arch, the convexity of which is toward the chest. In forced expiration, its upper point reaches as high as the fourth rib. In an ordinary inspiration, it is depressed as low as the seventh rib, which increases the capacity of the chest. -=-=-=-=-=-=-=-=-=-=-=-= 472. Describe the ribs. Explain figs. 93 and 94. 473. Describe the diaphragm. -=-=-=-=-=-=-=-=-=-=-=-= 474. The RESPIRATORY muscles are, in general, attached at one extremity to the parts about the shoulders, head, and upper portion of the spinal column. From these, they run downward and forward, and are attached, at the opposite extremity, to the sternum, clavicle, and upper rib. Other muscles are attached at one extremity to a rib above, and by the opposite extremity to a rib below. These fill the spaces between the ribs, and, from their situation, are called _in-ter-cost´al_ muscles. _Observation._ 1st. There are several actions of common occurrence, that are intimately connected with respiration; such as hiccough, sneezing, &c. Hiccough is an involuntary contraction of the muscles of respiration, particularly the diaphragm. 2d. Sneezing is a violent, involuntary contraction of the respiratory muscles, as in hiccough. When an acrid stimulant, as snuff, is applied to the mucous membrane of the nose, an irritation is produced which is accompanied by a violent expulsion of air from the lungs. This is owing to the connection between the nasal and respiratory nerves. -=-=-=-=-=-=-=-=-=-=-=-= What is its form when not in action? 474. Where do the respiratory muscles make their attachment? What name is given to those muscles that fill the places between the ribs? What is hiccough? What is sneezing? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXIV. PHYSIOLOGY OF THE RESPIRATORY ORGANS. 475. RESPIRATION, or breathing, is that process by which air is taken into the lungs and expelled from them. The object of respiration is, 1st. To supply the system with oxygen, which is essential to the generation of animal heat; 2d. To convert the chyle into blood. This is done by the oxygen of the inspired air; 3d. To relieve the organs of the body of the principal elements (carbon and hydrogen) that compose the old and useless particles of matter. The organs of the system, as already mentioned, are principally composed of carbon, hydrogen, oxygen, and nitrogen. 476. By the action of the lymphatics and capillary veins, the old and worn-out particles are conveyed into the veins of the systemic circulation. The hydrogen, in form of watery vapor, is easily discharged in the perspiration and other secretions. The nitrogen and oxygen are, or may be, separated from the blood, through the agency of several different organs; but carbon does not escape so readily. It is probable that a part of the surplus carbon of the venous blood is secreted by the liver; but a far greater amount passes to the lungs, and these may be considered as special organs designed to separate this element from the venous blood. 477. An ordinary inspiration may be accomplished by the action of the diaphragm, and a slight elevation of the ribs. In full inspiration, the diaphragm is not only more depressed but the ribs are evidently elevated. To produce this effect on the ribs, two sets of muscles are called into action. Those which are attached to the upper rib, sternum, and clavicle, contract and elevate the lower and free extremities of the ribs. This enlarges the cavity of the chest between the spinal column and the sternum. But the lateral diameter, in consequence, is only slightly increased, because the central portion of the ribs sinks lower than their posterior extremities, or their cartilaginous attachment to the sternum. -=-=-=-=-=-=-=-=-=-=-=-= 475-494. _Give the physiology of the respiratory organs._ 475. What is respiration? What is the principal object in breathing? 476. How are the useless atoms of matter conveyed into the veins of the systemic circulation? How may the principal elementary substances be separated from the blood? 477. How may an ordinary inspiration be accomplished? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 95. 6, Four of the vertebræ, to which are attached three ribs, (7, 7, 7,) with their intercostal muscles, (8, 8.) These ribs, in their natural position, have their anterior cartilaginous extremity at 4, while the posterior extremity is attached to the vertebræ, (6,) which are neither elevated nor depressed in respiration. 1, 1, and 2, 2, parallel lines, within which the ribs lie in their natural position. If the anterior extremity of the ribs is elevated from 4 to 5, they will not lie within the line 2, 2, but will reach the line 3, 3. If two hands extend from 1, 1, to 2, 2, they will effectually prevent the elevation of the ribs from 4 to 5, as the line 2, 2, cannot be moved to 3, 3.] -=-=-=-=-=-=-=-=-=-=-=-= What effect has a full inspiration on the ribs and diaphragm? How is the chest enlarged between the spinal column and sternum? What is said of the lateral diameter of the chest? Explain fig. 95. -=-=-=-=-=-=-=-=-=-=-=-= 478. The central portion of the ribs is raised by the action of intercostal muscles. The first, or upper rib, has but little movement; the second has more motion than the first, while the third has still more than the second. The second rib is elevated by the contraction of the muscles between it and the first. The third rib is raised by the action of two sets of muscles; one lies between the first and second ribs, the other between the second and third. The motion of each succeeding rib is increased, because it is not only acted upon by the muscles that move the ribs above, but by an additional intercostal; so that the movement of the twelfth rib is very free, as it is elevated by the contraction of eleven muscles. 479. The tenth rib is raised eight times as much as the second rib, and the lateral diameter of the lower portion of the chest is increased in a corresponding degree. At the same time, the muscular margin of the diaphragm contracts, which depresses its central portion; and in this way, the chest is enlarged forward, laterally, and downward, simultaneously with the relaxation of the walls of the abdomen. 480. The lungs follow the variations of capacity in the chest, expanding their air-cells when the latter is enlarged, and contracting when the chest is diminished. Thus, when the chest is expanded, the lungs follow, and consequently a vacuum is produced in their air-cells. The air then rushes through the mouth and nose into the trachea and its branches, and fills the vacuum as fast as it is made. This mechanical process constitutes _inspiration_. 481. After the expansion of the chest, the muscles that elevated the ribs relax, together with the diaphragm. The elasticity of the cartilages of the ribs depresses them, and the cavity of the chest is diminished, attended by the expulsion of a portion of the air from the lungs. At the same time, the muscles that form the front walls of the abdominal cavity, contract, and press the alimentary canal, stomach, and liver, upward against the diaphragm; this, being relaxed, yields to the pressure, rises upward, and presses upon the lungs, which retreat before it, and another portion of air is expelled from these organs. This process is called _expiration_. -=-=-=-=-=-=-=-=-=-=-=-= 478. Describe the action of the intercostal muscles upon the ribs. 479. How does the elevation of the tenth rib compare with the second? What effect has this elevation upon the lateral diameter of the chest? 480. Describe the process of inspiration. 481. Describe the process by which the air is forced out of the lungs. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 96. A front view of the chest and abdomen in respiration. 1, 1, The position of the walls of the chest in inspiration. 2, 2, 2, The position of the diaphragm in inspiration. 3, 3, The position of the walls of the chest in expiration. 4, 4, 4, The position of the diaphragm in expiration. 5, 5, The position of the walls of the abdomen in inspiration. 6, 6, The position of the abdominal walls in expiration.] 482. Thus it is obvious that the enlargement of the chest, or inspiration, is produced in two ways: 1st. By the depression of the convex portion of the diaphragm; 2d. By the elevation of the ribs. On the contrary, the contraction of the chest, or expiration, is produced by the depression of the ribs, and elevation of the central part of the diaphragm. These movements are successive during life, and constitute _respiration_. -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 96. 482. In how many ways may the chest be enlarged, and how is it accomplished? How is the contraction of the chest effected? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 97. A side view of the chest and abdomen in respiration. 1, The cavity of the chest. 2, The cavity of the abdomen. 3, The line of direction for the diaphragm when relaxed in expiration. 4, The line of direction for the diaphragm when contracted in inspiration. 5, 6, The position of the front walls of the chest and abdomen in inspiration. 7, 8, The position of the front walls of the abdomen and chest in expiration.] _Experiment._ Place the ear upon the chest of a person, and a murmuring sound will be heard, somewhat like the soft sighings of the wind through forest trees. This sound is caused by the air rushing in and out of the lungs, and is peculiarly distinct in the child. -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 97. How may the murmur of respiration be heard? -=-=-=-=-=-=-=-=-=-=-=-= 483. It is not easy to decide how much air is taken into the lungs at each inspiration. The quantity, however, must vary in different individuals, from the difference in the condition and expansion of the lungs, together with the size of the chest. From numerous experiments, the quantity, at an ordinary inspiration, of a common-sized man, is fixed at forty cubic inches. It has been estimated that one hundred and seventy cubic inches can be thrown out of the lungs by a forcible expiration, and that there remain in the lungs two hundred and twenty cubic inches; so that these organs, in their quiescent state, may be considered as containing about three hundred and ninety cubic inches of air, or more than a gallon. 484. Respiration is more frequent in females and children than in adult men. In diseases, particularly those of the lungs, it is more increased in frequency than the action of the heart. In health, the smallest number of inspirations in a minute by an adult, is not less than fourteen, and they rarely exceed twenty-five. Eighteen may be considered an average number. The quantity of oxygen taken into the lungs at each inspiration is about eight cubic inches, one half of which disappears in every act of respiration. _Observation._ Under different circumstances, however, the consumption of oxygen varies. It is greater when the temperature is low, than when it is high; and during digestion the consumption has been found one half greater than when the stomach was empty. -=-=-=-=-=-=-=-=-=-=-=-= 483. Can it be ascertained with accuracy how much air is taken into the lungs at each inspiration? Why not? What is the probable quantity that an ordinary sized man inspires? How much can be thrown out of the lungs at a forcible expiration, and how much remains in the lungs? From these calculations, how much may they contain in their quiescent state? 484. In whom is respiration most frequent? How in disease? How in health? How many may be considered an average number? When is the consumption of oxygen the greatest? -=-=-=-=-=-=-=-=-=-=-=-= 485. Dr. Southwood Smith has lately performed a series of very interesting experiments, from which he deduces the following general results: "1st. The volume of air ordinarily present in the lungs is about twelve pints. 2d. The volume of air received by the lungs at an ordinary inspiration is one pint. 3d. The volume of air expelled from the lungs at an ordinary expiration, is a little less than one pint. 4th. Of the volume of air received by the lungs at one inspiration, only one fourth part is decomposed at one action of the heart. 5th. The quantity of blood that flows to the lungs, to be acted upon by the air at one action of the heart, is two ounces, and this is acted on in less than one second of time. 6th. The quantity of blood in the whole body of the human adult, is twenty-five pounds avoirdupois, or twenty pints. 7th. In the mutual action that takes place between the air and blood, every twenty-four hours, the air loses thirty-seven ounces of oxygen, and the blood fourteen ounces of carbon." 486. Apparently, atmospheric air is a simple element. But chemical analysis shows its composition to be oxygen and nitrogen, in the proportion of twenty-one parts of the former, and about seventy-nine of the latter. In addition, there is a small amount of vapor of water and carbonic acid. The pressure of this invisible, elastic fluid upon the body of an ordinary sized adult, is estimated to equal thirty-five thousand pounds. 487. The principal substance of a vitiated character in the dark-colored blood is carbonic acid. And since there is no chemical affinity between the oxygen and nitrogen of the air, the former readily unites with some of the elements of the blood. Hence, whenever blood is presented to the air in the lungs, the oxygen leaves the nitrogen, and becomes mixed with the circulating fluid. (Appendix J.) -=-=-=-=-=-=-=-=-=-=-=-= 485. State the 1st, 2d, 3d, and 4th deductions from the experiments of Dr. Southwood Smith. The 5th, 6th, and 7th. 486. Of what is atmospheric air composed? What is the weight of air upon a common sized man? 487. What is the principal substance of a vitiated character in the dark-colored blood? What is said of the chemical affinity between oxygen and nitrogen? -=-=-=-=-=-=-=-=-=-=-=-= 488. Again, carbonic acid and water have a stronger affinity for atmospheric air than for the other elements of the blood. Consequently, when they are brought into contact with the air in the lungs, the carbonic acid and water leave the other constituents of the blood, and unite with the air. In this way the bluish, or impure blood is relieved of its impurities, and becomes the red, or pure blood, which contains the principles so essential to life. (Appendix K.) 489. The formation of carbonic acid and water, eliminated from the system through the lungs and skin, is explained by the following theory: In the lungs and upon the skin the oxygen separates from the nitrogen and unites with the blood in the capillary vessels of these organs. The oxygen is conveyed with the blood to the capillary arteries and veins of the different tissues of the system. In these membranes there is a chemical union of the oxygen with the carbon and hydrogen contained in the blood and waste atoms of the system. This combustion, or union of oxygen with carbon and hydrogen, is attended with the disengagement of heat, and the formation of carbonic acid and water. (Appendix L.) 490. The following experiment will illustrate the passage of fluids through membranes, and the different affinity of gases for each other. Put a mixture of water and alcohol into a phial and leave it uncorked. Both the water and alcohol have a greater affinity for air than for each other. Alcohol has a greater affinity for the air, and will be diffused through it more readily than the water, when there is no intervening obstacle. But tie a piece of bladder over the mouth of the phial, and let it stand a few days,--the water will leave the alcohol, and pass through the membrane. By the aid of this experiment, we shall endeavor to explain the interchange of fluids in the lungs. -=-=-=-=-=-=-=-=-=-=-=-= 488. What is formed when oxygen unites with carbon or hydrogen? 489. Give the theory for the formation of carbonic acid and watery vapor thrown out of the system. 490. Illustrate the passage of fluids through membranes, and the different affinities of gases. -=-=-=-=-=-=-=-=-=-=-=-= 491. The walls of the air-vesicles, and coats of the blood-vessels, are similar, in their mechanical arrangement, to the membranous bladder in the before described experiment. As the oxygen of the air has greater affinity for blood than for nitrogen, so it permeates the membranes that intervene between the air and blood more readily than the nitrogen. As the carbonic acid and water have a greater affinity for air than for the other elements of the blood, so they will also pass through the walls of the blood-vessels and air-cells more readily than the other elements of the dark-colored blood. [Illustration: Fig. 98. 1, A bronchial tube divided into three branches. 2, 2, 2, Air-cells. 3, Branches of the pulmonary artery, that spread over the air-cells. Through the pulmonary artery the dark, impure blood is carried to the air-cells of the lungs. 4, Branches of the pulmonary vein, that commence at the minute terminations of the pulmonary artery. Through the pulmonary vein the red blood is returned to the heart.] 492. As the impure blood is passing in the minute vessels over the air-cells, the oxygen passes through the thin coats of the air-cells and blood-vessels, and unites with the blood. At the same time, the carbonic acid and water leave the blood, and pass through the coats of the blood-vessels and air-cells, and mix with the air in the cells. These are thrown out of the system every time we breathe. This interchange of products produces the change in the color of the blood. -=-=-=-=-=-=-=-=-=-=-=-= Explain fig. 98. 492. How and where is the blood changed? -=-=-=-=-=-=-=-=-=-=-=-= _Experiment._ Fill a bladder with dark blood drawn from any animal. Tie the bladder closely, and suspend it in the air. In a few hours, the blood next to the membrane will have become of a bright red color. This is owing to the oxygen from the air passing through the bladder, and uniting with the blood, while the carbonic acid has escaped through the membrane. [Illustration: Fig. 99. An ideal view of the pulmonary circulation. 1, 1, The right lung. 2, 2, The left lung. 3, The trachea. 4, The right bronchial tube. 5, The left bronchial tube. 6, 6, 6, 6, Air-cells. 7, The right auricle. 8, The right ventricle. 9, The tricuspid valves. 10, The pulmonary artery. 11, The branch to the right lung. 12, The branch to the left lung. 13, The right pulmonary vein. 14, The left pulmonary vein. 15, The left auricle. 16, The left ventricle. 17, The mitral valves.] 493. The presence of carbonic acid and watery vapor in the expired air, can be proved by the following experiments: 1st. Breathe into lime-water, and in a few minutes it will become of a milk-white color. This is owing to the carbonic acid of the breath uniting with the lime, forming the _carbonate of lime_. 2d. Breathe upon a cold, dry mirror for a few minutes, and it will be covered with moisture. This is condensed vapor from the lungs. In warm weather, this watery vapor is invisible in the expired air, but in a cold, dry morning in winter, the successive jets of vapor issuing from the mouth and nose are sufficiently obvious. -=-=-=-=-=-=-=-=-=-=-=-= Give the experiment showing that oxygen changes the dark-colored blood to a bright red color. What is represented by fig. 99? 493. How can the presence of carbonic acid in the lungs be proved? -=-=-=-=-=-=-=-=-=-=-=-= 494. From the lungs are eliminated other impurities beside carbonic acid, the perceptible quality of which is various in different persons. The offensive breath of many persons may be caused by decayed teeth, or the particles of food that may be retained between them, but it often proceeds from the secretion, in the lungs, of certain substances which previously existed in the system. _Illustration._ When spirituous liquors are taken into the stomach, they are absorbed by the veins and mixed with the dark-colored blood, in which they are carried to the lungs to be expelled from the body. This will explain the fact, which is familiar to most persons, that the odor of different substances is perceptible in the breath, or expired air, long after the mouth is free from these substances. -=-=-=-=-=-=-=-=-=-=-=-= How the watery vapor? 494. Are there other excretions from the lungs? Give the illustration. -=-=-=-=-=-=-=-=-=-=-=-= _Note._ Let the anatomy and physiology of the respiratory organs be reviewed from figs. 96, 97, and 99, or from anatomical outline plates Nos. 5 and 7. CHAPTER XXV. HYGIENE OF THE RESPIRATORY ORGANS. 495. For man to enjoy the highest degree of health, it is necessary that the impure "venous" blood be properly changed. As this is effected in the lungs by the action of the air, it follows that this element, when breathed, should be pure, or contain twenty-one per cent. of oxygen to about seventy-nine per cent. of nitrogen. 496. The volume of air expelled from the lungs is somewhat less than that which is inspired. The amount of loss varies under different circumstances. An eightieth part of the volume taken into the lungs, or half a cubic inch, may be considered an average estimate. 497. _The quality and purity of the air is affected by every respiration._ 1st. The quantity of oxygen is diminished. 2d. The amount of carbonic acid is increased. 3d. A certain proportion of watery vapor is ejected from the lungs in the expired air. Of the twenty-one parts of oxygen in the inspired air, only eighteen parts are expired, while the carbonic acid and watery vapor are increased about four per cent. The quantity of nitrogen is nearly the same in the expired as in the inspired air. _Observation._ It is now fully ascertained that while the chemical composition of the blood is essentially changed, its weight remains the same, as the carbon and hydrogen discharged are equal to the united weight of the oxygen and nitrogen absorbed. -=-=-=-=-=-=-=-=-=-=-=-= 495-546. _Give the hygiene of the respiratory organs._ 495. What is necessary that man enjoy the highest degree of health? 496. How does the volume Of expired air compare with that which was inspired? Does this loss vary, and what is an average estimate? 497. How is the purity of the air affected by respiration? How is the inhaled oxygen affected? What effect on the carbonic acid and watery vapor? On the nitrogen? What is said respecting the weight of the blood? -=-=-=-=-=-=-=-=-=-=-=-= 498. If one fourth part of the volume of air received by the lungs at one inspiration is decomposed at one "beat" of the heart, it might be supposed that if the expired air be again received into the lungs, one half of the oxygen would be consumed, and, in a similar ratio, if re-breathed four times, all the oxygen would be consumed. But it does not follow, if the air is thus re-breathed, that the same changes will be effected in the lungs. For air that has been inspired does not part with its remaining oxygen as freely as when it contains the proper amount of this life-giving element, and thus the changes in the impure blood are not so completely effected. _Illustration._ In the process of dyeing, each successive article immersed in the dye weakens it; but it does not follow that the dye each time is affected in the same degree, or that the coloring matter by repeated immersions can be wholly extracted. The same principle applies to the exchange of oxygen and carbonic acid gas in the lungs. 499. _If the inspired air is free from moisture and carbonic acid, these substances contained in the blood will be more readily imparted to it._ When the air is loaded with vapor, they are removed more slowly; but if it is saturated with moisture, no vapor will escape from the blood through the agency of the lungs. This may be illustrated by the following experiment: Take two and a half pounds of water, add to it half a pound of common salt, (chloride of sodium,) and it will readily mix with the water; and to this solution add the same quantity of salt, and it will be dissolved more slowly. Again, add more salt, and it will remain undissolved, as the water has become saturated by the pound before dissolved. -=-=-=-=-=-=-=-=-=-=-=-= 498. Does air that is re-breathed freely impart its oxygen? Why? 499. What is the effect on the blood when the air is free from vapor and carbonic acid? When loaded with vapor? When saturated? How is this illustrated? -=-=-=-=-=-=-=-=-=-=-=-= 500. The principle in this experiment is analogous to that of the union between carbonic gas and atmospheric air. Allen and Pepy showed by experiment, that air which had been once breathed, contained eight and a half per cent. of carbonic acid. They likewise showed, that no continuance of the respiration of the same air could make it take up more than ten per cent. This is the point of saturation. _Experiment._ Sink a glass jar that has a stop-cock, or one with a glass stopper, into a pail of water, until the air is expelled from the jar. Fill the lungs with air, and retain it in the chest a short time, and then breathe into the jar, and instantly close the stop-cock. Close the opening of the jar that is under the water with a piece of paper laid on a plate of sufficient size to cover the opening, invert the jar, and sink into it a lighted candle. The flame will be extinguished as quickly as if put in water.[15] Remove the carbonic acid by inverting the jar, and place a lighted candle in it, and the flame will be as clear as when out of the jar. [15] As a substitute for a jar with a stop-cock, take a piece of lead pipe bent in the form of a siphon, and insert it in the mouth of a reversed jar. This experiment is as conclusive whether the air is inhaled once only or breathed many times. _Observations._ 1st. It is familiarly known that a taper will not burn where carbonic acid exists in any considerable quantity, or when there is a marked deficiency of oxygen. From this originated the judicious practice of sinking a lighted candle into a well or pit before descending into it. If the flame is extinguished, respiration cannot there be maintained, and life would be sacrificed should a person venture in, until the noxious air is removed. -=-=-=-=-=-=-=-=-=-=-=-= 500. What did the experiments of Allen and Pepy show? How can the presence of carbonic gas in the expired air be demonstrated? State observation 1st. Observation 2d. -=-=-=-=-=-=-=-=-=-=-=-= 2d. It is the action of carbonic acid upon the respiratory organs, that gives rise to a phenomenon frequently seen in mines and caves. A man may enter these subterranean rooms, and feel no inconvenience in breathing; but the dog that follows him, falls apparently dead, and soon dies if not speedily removed to pure air. This arises from the fact that this gas is heavier than air, and sinks to the bottom of the room or cave. 3d. While it is true that carbonic acid possesses properties that render it unfit to be breathed, it is, notwithstanding, productive of very agreeable effects, when conveyed into the stomach. It forms the sparkling property of mineral waters, and fills the bubbles that rise when beer or cider is fermenting. 501. _Pure atmospheric air is best adapted to a healthy action of the system._ As the air cannot be maintained pure under all circumstances, the question may be asked, To what degree may the air be vitiated and still sustain life? and what is the smallest quantity of pure air a person needs each minute to maintain good health? Birnan says, that air which contains more than three and a half per cent. of carbonic acid is unfit for respiration, and, as air once respired contains eight and a half per cent. of carbonic acid, it clearly shows that it is not fitted to be breathed again. 502. No physiologist pretends that less than seven cubic feet of air are adequate for a man to breathe each minute, while Dr. Reid allows ten feet. The necessity of fifteen or twenty times the amount of air actually taken into the lungs, arises from the circumstance, that the expired air mixes with and vitiates the surrounding element that has not been inhaled. 503. _The quantity of air which different persons actually need, varies._ The demand is modified by the size, age, habits, and condition of the body. A person of great size who has a large quantity of blood, requires more air than a small man with a less amount of circulating fluid. Individuals whose labor is active, require more air than sedentary or idle persons, because the waste of the system is greater. On the same principle, the gormandizer needs more of this element than the person of abstemious habits. So does the growing lad require more air than an adult of the same weight, for the reason that he consumes more food than a person of mature years. Habit also exerts a controlling influence. A man who works in the open air suffers more when placed in a small, unventilated room, than one who is accustomed to breathe the confined air of workshops. -=-=-=-=-=-=-=-=-=-=-=-= Observation 3d. 501. What questions may be asked respecting the inspired air? Give the remark of Birnan. 502. How many cubic feet of air are adequate for a man to breathe each minute? How much does Dr. Reid allow? 503. Mention some reasons why different persons do not require the same amount of air. -=-=-=-=-=-=-=-=-=-=-=-= 504. _Air, in which lamps will not burn with brilliancy, is unfitted for respiration._ In crowded rooms, which are not ventilated, the air is vitiated, not only by the abstraction of oxygen and the deposition of carbonic acid, but by the excretions from the skin and lungs of the audience. The lamps, under such circumstances, emit but a feeble light. Let the oxygen gas be more and more expended, and the lamps will burn more and more feebly, until they are extinguished. _Illustrations._ 1st. The effects of breathing the same air again and again, are well illustrated by an incident that occurred in one of our halls of learning. A large audience had assembled in an ill-ventilated room, to listen to a lecture; soon the lamps burned so dimly that the speaker and audience were nearly enveloped in darkness. The oppression, dizziness, and faintness experienced by many of the audience induced them to leave, and in a few minutes after, the lamps were observed to rekindle, owing to the exchange of pure air on opening the door. -=-=-=-=-=-=-=-=-=-=-=-= How is it with the laborer? With the gormandizer? With the person that works in the open air? 504. What effect has impure air on a burning lamp? Give the illustration of the effects of impure air on lighted lamps. -=-=-=-=-=-=-=-=-=-=-=-= 2d. In the "Black Hole of Calcutta," one hundred and forty-six Englishmen were shut up in a room eighteen feet square, with only two small windows on the same side to admit air. On opening this dungeon, ten hours after their imprisonment, only twenty-three were alive. The others had died from breathing impure air. 505. _Air that has become impure from the abstraction of oxygen, an excess of carbonic acid, or the excretions from the lungs and skin, has a deleterious effect on the body._ When this element is vitiated from the preceding causes, it prevents the proper arterialization, or change in the blood. For this reason, pure air should be admitted freely and constantly into work-shops and dwelling-houses, and the vitiated air permitted to escape. This is of greater importance than the warming of these apartments. We can compensate for the deficiency of a stove, by an extra garment or an increased quantity of food; but neither garment, exercise, nor food will compensate for pure air. 506. _School-rooms should be ventilated._ If they are not, the pupils will be restless, and complain of languor and headache. Those unpleasant sensations are caused by a want of pure air, to give an adequate supply of oxygen to the lungs. When pupils breathe for a series of years such vitiated air, their life is undoubtedly shortened, by giving rise to consumption and other fatal diseases. _Illustration._ A school-room thirty feet square and eight feet high, contains 7200 cubic feet of air. This room will seat sixty pupils, and, allowing ten cubic feet of air to each pupil per minute, all the air in the room will be vitiated in twelve minutes. _Observation._ In all school-rooms where there is not adequate ventilation, it is advisable to have a recess of five or ten minutes each hour. During this time, let the pupils breathe fresh air, and open the doors and windows, so that the air of the room shall be completely changed. -=-=-=-=-=-=-=-=-=-=-=-= Of the effects of breathing impure air. 505. In preserving health, what is of greater importance than warming the room? 506. Why should a school-room be ventilated? Give the illustration. -=-=-=-=-=-=-=-=-=-=-=-= 507. _Churches, concert halls, and all rooms designed for a collection of individuals, should be amply ventilated._ While the architect and workmen are assiduous in giving these public rooms architectural beauty and splendor, by adorning the ceiling with Gothic tracery, rearing richly carved columns, and providing carefully for the warming of the room, it too frequently happens that no direct provision is made for the change of that element which gives us beauty, strength, and life. _Illustration._ A hall sixty feet by forty, and fifteen feet high, contains 36,000 cubic feet of air. A hall of this size will seat four hundred persons; by allowing ten cubic feet of air to each person per minute, the air of the room will be rendered unfit for respiration in nine minutes. 508. _Railroad cars, cabins of steam and canal-boats, omnibuses, and stage-coaches, require ample ventilation._ In the construction of these public conveyances, too frequently, the only apparent design is, to seat the greatest number of persons, regardless of the quantity and character of the air to maintain health and even life. The character of the air is only realized when, from the fresh, pure air, we enter a crowded cabin of a boat or a closed coach; then the vitiated air from animal excretions and noxious gases is offensive, and frequently produces sickness. 509. The influence of habit is strikingly expressed by Birnan, in the "Art of Warming and Ventilating Rooms:" "Not the least remarkable example of the power of habit is its reconciling us to practices which, but for its influence, would be considered noxious and disgusting. We instinctively shun approach to the dirty, the squalid, and the diseased, and use no garment that may have been worn by another. We open sewers for matters that offend the sight or the smell, and contaminate the air. We carefully remove impurities from what we eat and drink, filter turbid water, and fastidiously avoid drinking from a cup that may have been pressed to the lips of a friend. On the other hand, we resort to places of assembly, and draw into our mouths air loaded with effluvia from the lungs, skin, and clothing of every individual in the promiscuous crowd--exhalations offensive, to a certain extent, from the most healthy individuals; but when arising from a living mass of skin and lungs, in all stages of evaporation, disease, and putridity,--prevented by the walls and ceiling from escaping--they are, when thus concentrated, in the highest degree deleterious and loathsome." -=-=-=-=-=-=-=-=-=-=-=-= What suggestion when a school-room is not ventilated? 507. What is said in regard to ventilating churches, concert halls, &c.? State the illustration. 508. What remarks relative to public conveyances? 509. State the influence of habit by Birnan. -=-=-=-=-=-=-=-=-=-=-=-= 510. _The sleeping-room should be so ventilated that the air in the morning will be as pure as when retiring to rest in the evening._ Ventilation of the room would prevent morning headaches, the want of appetite, and languor--so common among the feeble. The impure air of sleeping-rooms probably causes more deaths than intemperance. Look around the country, and those who are most exposed, who live in huts but little superior to the sheds that shelter the farmer's flocks, are found to be the most healthy and robust. Headaches, liver complaints, coughs, and a multitude of nervous affections, are almost unknown to them; not so with those who spend their days and nights in rooms in which the sashes of the windows are calked, or perchance doubled, to prevent the keen but healthy air of winter from entering their apartments. Disease and suffering are their constant companions. -=-=-=-=-=-=-=-=-=-=-=-= 510. What is said of the ventilation of sleeping-rooms? What would adequate ventilation prevent? Give a common observation. -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ By many, sleeping apartments twelve feet square and seven feet high, are considered spacious for two persons, and good accommodations for four to lodge in. An apartment of this size contains 1008 cubic feet of air. Allowing ten cubic feet to each person per minute, two occupants would vitiate the air of the room in fifty minutes, and four in twenty-five minutes. When lodging-rooms are not ventilated, we would strongly recommend early rising. 511. _The sick-room, particularly, should be so arranged that the impure air may escape, and pure air be constantly admitted into the room._ It is no unusual practice in some communities, when a child or an adult is sick of an acute disease, to prevent the ingress of pure air, simply from the apprehension of the attendants, that the patient will contract a cold. Again, the prevalent custom of several individuals sitting in the sick-room, particularly when they remain there for several hours, tends to vitiate the air, and, consequently, to increase the suffering and danger of the sick person. In fevers or inflammatory diseases of any kind, let the patient breathe pure air; for the purer the blood, the greater the power of the system to remove disease, and the less the liability to contract colds. _Observation._ Among children, convulsions, or "fits," usually occur when they are sleeping. In many instances, these are produced by the impure air which is breathed. To prevent these alarming and distressing convulsions, the sleeping-room should be ventilated, and there should be no curtains around the bed, or coverings over the face, as they produce an effect similar to that experienced when sleeping in a small, unventilated room. To relieve a child when convulsed, carry it into the open air. -=-=-=-=-=-=-=-=-=-=-=-= What is said of the size of sleeping-rooms? 511. What is said of the sick-room? Mention some prevailing customs in reference to these rooms. What is said of convulsions among children? -=-=-=-=-=-=-=-=-=-=-=-= 512. _While occupying a room, we are insensible of the gradual vitiation of the air._ This is the result of the diminished sensibility of the nervous system, and gradual adaptation of the organs to blood of a less stimulating character. This condition is well illustrated in the hibernating animals. We are insensible of the impure air of unventilated sleeping-rooms, until we leave them for a walk or ride. If they have been closed, we are made sensible of the character of the air as soon as we reënter them, for the system has regained its usual sensibility while inhaling a purer atmosphere. 513. _In the construction of every inhabited room, there should be adequate means of ventilation, as well as warming._ No room is well ventilated, unless as much pure air is brought into it as the occupants vitiate at every respiration. This can be effected by making an aperture in the ceiling of the room, or by constructing a ventilating flue in the chimney. This should be in contact with the flues for the escape of smoke, but separated from them by a thin brick partition. The hot air in the smoke flues will warm the separating brick partition, and consequently rarefy the air in the ventilating flue. Communication from every room in a house should be had to such flues. The draught of air can be regulated by well-adjusted registers, which in large rooms should be placed near the floor as well as near the ceiling. 514. While provision is made for the escape of rarefied impure air, we should also provide means by which pure air may be constantly admitted into the room, as the crevices of the doors and windows are not always sufficient; and, if they should be adequate, air can be introduced in a more convenient, economical, and appropriate manner. There should be an aperture opposite the ventilating flue, at or near the floor, to connect with the outer walls of the building or external air. But if pure heated air is introduced into the room, it obviates the necessity of the introduction of the external air.[16] [16] Mr. Frederick Emerson, of Boston, has devised a simple and effective apparatus for removing vitiated air from a room. It is successfully used upon all the public school-houses of Boston. It is now being generally applied to the school-houses and other public buildings, as well as private dwellings, of New England. -=-=-=-=-=-=-=-=-=-=-=-= 512. Why are we insensible to the gradual vitiation of the air of an unventilated room? 513. What is very important in the building of every inhabited room? How can a room be well ventilated? 514. What is said relative to a communication with the external air? -=-=-=-=-=-=-=-=-=-=-=-= 515. In warming rooms, the hot air furnaces, or box and air-tight stoves converted into hot air furnaces, should be used in preference to the ordinary stoves. The air thus introduced into the room is pure as well as warm. In the adaptation of furnaces to dwelling-houses, &c., it is necessary that the air should pass over an ample surface of iron moderately heated; as a red heat abstracts the oxygen from the contiguous air, and thus renders it unfit to be respired.[17] [17] Dr. Wyman's valuable work on "Ventilation," and the work of Henry Barnard, Esq., on "School-house architecture," can be advantageously consulted, as they give the practical methods of ventilating and warming shops, school-rooms, dwelling-houses, public halls, &c. _Observation_. Domestic animals need a supply of pure air as well as man. The cows of cities, that breathe a vitiated air, have, very generally, tubercles. Sheep that are shut in a confined air, die of a disease called the "rot," which is of a tuberculous character. Interest and humanity require that the buildings for animals be properly ventilated. -=-=-=-=-=-=-=-=-=-=-=-= 515. How should rooms be warmed? What is necessary in the adaptation of furnaces to dwelling-houses? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXVI. HYGIENE OF THE RESPIRATORY ORGANS, CONTINUED. 516. The change that is effected in the blood while passing through the lungs, not only depends upon the purity of the air, but the amount inspired. The quantity varies according to the size of the chest, and the movement of the ribs and diaphragm. 517. _The size of the chest and lungs can be reduced by moderate and continued pressure._ This is most easily done in infancy, when the cartilages and ribs are very pliant; yet it can be effected at more advanced periods of life, even after the chest is fully developed. For want of knowledge of the pliant character of the cartilages and ribs in infants, too many mothers, unintentionally, contract their chests, and thus sow the seeds of disease by the close dressing of their offspring. 518. If slight but steady pressure be continued from day to day and from week to week, the ribs will continue to yield more and more, and after the expiration of a few months, the chest will become diminished in size. This will be effected without any suffering of a marked character; but the general health and strength will be impaired. It is not the violent and ephemeral pressure, but the moderate and protracted, that produces the miscalled, "genteel," contracted chests. 519. The style of dress which at the present day is almost universal, is a prolific cause of this deformity. These baneful fashions are copied from the periodicals, so widely circulated, containing a "fashion plate of the latest fashions, from Paris." In every instance; the contracted, deformed, and, as it is called, lady-like waist, is portrayed in all its fascinating loveliness. These periodicals are found on almost every centre-table, and exercise an influence almost omnipotent. If the plates which corrupt the morals are excluded by civil legislation, with the same propriety ought not those to be suppressed that have a tendency so adverse to health? -=-=-=-=-=-=-=-=-=-=-=-= 516. What varies the amount of air received into the lungs? 517. How can the size of the chest be diminished? When is this most easily effected? 518. How are the miscalled, "genteel," contracted chests usually produced? 519. What is said of the style of the dress at the present day? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 100. A correct outline of the Venus de Medici, the beau ideal of female symmetry.] [Illustration: Fig. 101. An outline of a well-corseted modern beauty. One has an artificial, insect waist; the other, a natural waist. One has sloping shoulders, while the shoulders of the other are comparatively elevated, square, and angular. The proportion of the corseted female below the waist, is also a departure from the symmetry of nature.] _Observations._ 1st. The Chinese, by compressing the feet of female children, prevent their growth; so that the foot of a _Chinese belle_ is not larger than the foot of an American girl of five years. -=-=-=-=-=-=-=-=-=-=-=-= What does fig. 100 represent? Fig. 101? Give observation 1st. -=-=-=-=-=-=-=-=-=-=-=-= 2d. The American women _compress their chests_, to prevent their growth; so that the chest of an _American belle_ is not larger than the chest of a Chinese girl of five years. Which country, in this respect, exhibits the greater intelligence? 3d. The chest can be deformed by making the linings of the waists of the dresses tight, as well as by corsets. Tight vests, upon the same principle, are also injurious. 520. In children, who have never worn close garments, the circumference of the chest is generally about equal to that of the body at the hips; and similar proportions would exist through life, if there were no improper pressure of the clothing. This is true of the laboring women of the Emerald Isle, and other countries of Europe, and in the Indian female, whose blanket allows the free expansion of the chest. The symmetrical statues of ancient sculptors bear little resemblance to the "beau ideal" of American notions of elegant form. This perverted taste is in opposition to the laws of nature. The design of the human chest is not simply to connect the upper and lower portions of the body, like some insects, but to form a case for the protection of the vital organs. 521. _Individuals may have small chests from birth._ This, to the particular individual, is natural; yet it is adverse to the great and general law of Nature relative to the size of the human chest. Like produces like, is a general law of the animal and vegetable kingdoms. No fact is better established, than that which proves the hereditary transmission from parents to children of a constitutional liability to disease and the same may be said in regard to their conformations. If the mother has a small, taper waist, either hereditary or acquired, this form may be impressed on her offspring;--thus illustrating the truthfulness of scripture, "that the sins of the parents shall be visited upon the children unto the third and fourth generation." -=-=-=-=-=-=-=-=-=-=-=-= Observation 2d. Observation 3d. 520. What is the size of the chest of a child that has always worn loose clothing? What is said of the size of the laboring women of Ireland, and the Indian female? How is it in ancient statues? What is the design of the chest? 521. What is a general law of both the animal and vegetable kingdoms? What fact in this connection is well established? -=-=-=-=-=-=-=-=-=-=-=-= 522. _The quantity of air inhaled is modified by the capacity of the respiratory organs._ The necessity of voluminous lungs may he elucidated by the following experiment: Suppose a gill of alcohol, mixed with a gill of water, be put into a vessel having a square foot of surface, and over the vessel a membrane be tied, and that the water will evaporate in twenty-four hours. If the surface had been only six inches square, only one fourth of the water would have evaporated through the membrane in the given time. If the surface had been extended to two square feet, the water would have evaporated in twelve hours. 523. Apply this principle to the lungs: suppose there are two hundred feet of carbonic acid to be carried out of the system every twenty-four hours. This gas, in that time, will pass through a vesicular membrane of two thousand square feet. If the lungs were diminished in size, so that there would be only one thousand square feet of vesicular membrane, the amount of carbonic acid would not, and could not, be eliminated from the system. Under such circumstances, the blood would not be purified. 524. Again; suppose the two thousand square feet of membrane would transmit two hundred cubic feet of oxygen into the system every twenty-four hours. If it should be diminished one half, this amount of oxygen would not pass into the blood. From the above illustrations we may learn the importance of well-developed chests and voluminous lungs; for, by increasing the size of the lungs, the oxygen is more abundantly supplied to the blood, and this fluid is more perfectly deprived of its carbon and hydrogen. -=-=-=-=-=-=-=-=-=-=-=-= What does this hereditary transmission prove? 522. How is the necessity of voluminous lungs illustrated? 525. How is this principle applied to the interchange of products in the lungs? -=-=-=-=-=-=-=-=-=-=-=-= 525. The chest is not only most expanded at its lower part, but the portion of the lungs that occupies this space of the thoracic cavity contains the greater part of the air-cells; and, from the lower two thirds of the lungs the greatest amount of carbonic acid is abstracted from the blood, and the greatest amount of oxygen gas is conveyed into the circulating fluid. Hence, contracting the lower ribs is far more injurious to the health than diminishing the size of the upper part of the chest. 526. The question is often asked, Can the size of the chest and the volume of the lungs be increased, when they have been injudiciously compressed, or have inherited this unnatural form? The answer is in the affirmative. The means for attaining this end are, a judicious exercise of the lungs, by walking in the open air, reading aloud, singing, sitting erect, and fully inflating the lungs at each act of inspiration. If the exercise be properly managed and persevered in, it will expand the chest, and give tone and health to the important organs contained in it. But, if the exercise be ill-timed or carried to excess, the beneficial results sought will probably not be attained. _Observation._ Scholars, and persons who sit much of the time, should frequently, during the day, breathe full and deep, so that the smallest air-cells may be fully filled with air. While exercising the lungs, the shoulders should be thrown back and the head held erect. 527. _The movement of the ribs and diaphragm is modified by the dress._ When the lungs are properly filled with air, the chest is enlarged in every direction. If any article of apparel is worn so tight as to prevent the full expansion of the chest and abdomen, the lungs, in consequence, do not receive air sufficient to purify the blood. The effect of firm, unyielding clothing, when worn tight, in preventing a due supply of air to the lungs, may be shown by the following illustration. -=-=-=-=-=-=-=-=-=-=-=-= 525. Why is it more injurious to contract the lower part of the chest than the upper? 526. How can the size of the chest be increased when it is contracted? Give the observation. 527. How is the movement of the ribs and diaphragm modified? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ If the diameter of a circle is three feet, the circumference will be nine feet. If the diameter is extended to four feet, the circumference will be increased to twelve feet. Should a tight band be thrown around a circle of nine feet, its diameter cannot be increased, for the circumference cannot be enlarged. 528. Any inelastic band, drawn closely around the lower part of the chest, or the abdomen, below the ribs, operates like the band in the preceding illustration, in restricting the movement of the ribs. When any article of dress encircles either the chest or abdomen, so as to prevent an increase of its circumference, it has an injudicious tendency, as it prevents the introduction of air in sufficient quantities to purify the blood. The question is not, How much restriction of the respiratory movements can be endured, and life continue? but, Does any part of the apparel restrict the movements? If it does, it is a violation of the organic laws; and though Nature is profuse in her expenditures, yet sooner or later, she sums up her account. 529. In determining whether the apparel is worn too tight, inflate the lungs, and, if no pressure is felt, no injurious effects need be apprehended from this cause. In testing the tightness of the dress, some persons will contract to the utmost the abdominal muscles, and thus diminish the size of the chest, by depressing the ribs; when this is done, the individual exclaims, "How loose my dress is!" This practice is both deceptive and ludicrous. A good test is, to put the hand on the chest below the arm; if there is no movement of the ribs during respiration, the apparel is too tight. The only reliable test, however, is a full inflation of the lungs. -=-=-=-=-=-=-=-=-=-=-=-= How is the effect of unyielding clothing, when worn tight, illustrated? 528. What effect has an inelastic band upon the lower part of the chest? What question is asked? 529. How can we determine whether the apparel is worn too tight? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Many individuals do not realize the small amount of force that will prevent the enlargement of the chest. This can be demonstrated by drawing a piece of tape tightly around the lower part of the chest of a vigorous adult, and confining it with the thumb and finger. Then endeavor fully to inflate the lungs, and the movement of the ribs will be much restricted. 530. _The position in standing and sitting influences the movement of the ribs and diaphragm._ When the shoulders are thrown back, and when a person stands or sits erect, the diaphragm and ribs have more freedom of motion, and the abdominal muscles act more efficiently; thus the lungs have broader range of movement than when the shoulders incline forward, and the body is stooping. 531. _Habit exercises an influence upon the range of the respiratory movements._ A person who has been habituated to dress loosely, and whose inspirations are full and free, suffers more from the tightness of a vest or waistband, than one, the range of movements of whose chest has long been subjected to tight lacing. 532. _The condition of the brain exercises a great influence upon respiration._ If the brain is diseased, or the mind depressed by grief, tormented by anxiety, or absorbed by abstract thought, the contractile energy of the diaphragm and muscles that elevate the ribs, is much diminished, and the lungs are not so fully inflated, as when the mind is influenced by joy or other exhilarating emotions. The depressing passions likewise lessen the frequency of respiration. By the influence of these causes, the blood is but partially purified, and the whole system becomes enfeebled. Here we may see the admirable harmony between the different parts of the body, and the adaptation of all the functions to each other. -=-=-=-=-=-=-=-=-=-=-=-= Give another test. How can the amount of pressure necessary to prevent the enlargement of the chest be demonstrated? 530. Show the effect of position on the movements of the ribs and diaphragm. 531. Show the effect of habit on the respiratory movements. 532. State the influence of the mind upon respiration. -=-=-=-=-=-=-=-=-=-=-=-= 533. As the quantity of air inhaled at each unimpeded inspiration in lungs of ample size, is about forty cubic inches, it follows, if the movement of the ribs and diaphragm is restricted by an enfeebled action of the respiratory muscles, or by any other means, the blood will not be perfectly purified. In the experiment, (§ 522, 523,) suppose forty cubic inches of air must pass over the membrane twenty times every minute, and that this is the amount required to remove the vapor which arises from the membrane; if only half of this amount of air be supplied each minute, only one half as much water will be removed from the alcohol through the membrane in twenty-four hours; consequently, the alcohol would be impure from the water not being entirely removed. 534. Restrain the elevation of the ribs and depression of the diaphragm, so that the quantity of air conveyed into the lungs will be reduced to twenty cubic inches, when forty are needed, and the results will be as follows: Only one half of the carbonic acid will be eliminated from the system, and the blood will receive but one half as much oxygen as it requires. This fluid will then be imperfectly oxydated, and partially freed of its impurities. The impure blood will be returned to the left side of the heart, and the whole system will suffer from an infringement of organic laws. -=-=-=-=-=-=-=-=-=-=-=-= 533. Illustrate the effect upon the blood when the respiratory muscles are enfeebled in their action. 534. Show how the blood is imperfectly purified by restricting the movements of the ribs and diaphragm. -=-=-=-=-=-=-=-=-=-=-=-= 535. _Scrofula, or consumption, frequently succeeds a depressed state of the nervous system._ These diseases arise from the deposition of tuberculous matter in different parts of the body. Those individuals who have met with reverses of fortune, in which character and property were lost, afford painful examples. Hundreds yearly die from the effect of depressed spirits, caused by disappointed hopes, or disappointed ambition. _Illustration._ A striking instance of the effects of mental depression is related by Lænnec. In a female religious establishment in France, great austerities were practised; the mind was absorbed in contemplating the terrible truths of religion, and in mortifying the flesh. The whole establishment, in the space of ten years, was several times depopulated--with the exception of the persons employed at the gate, in the kitchen, and garden--with that fatal disease, consumption. This institution did not long continue, but was suppressed by order of the French government. 536. _The purity of the blood is influenced by the condition of the lungs._ When the bronchial tubes and air-cells have become partially impervious to air, from pressure upon the lungs, from fluids in the chest, from tumors, or from the consolidation of the cells and tubes from disease,--as inflammation, or the deposition of yellow, cheesy matter, called tubercles,--the blood will not be purified, even if the air is pure, the lungs voluminous, and the respiratory movements unrestricted, as the air cannot permeate the air-cells. _Observations._ 1st. The twenty-three who escaped immediate death in the Black Hole of Calcutta were soon attacked with inflammation of the lungs, by which these organs were consolidated, and thus prevented the permeation of air into their cells. This disease of the lungs was caused by breathing vitiated air. -=-=-=-=-=-=-=-=-=-=-=-= 535. Mention some of the effects of mental depression upon the body. What is related by Lænnec? 536. Does the condition of the lungs influence the purity of the blood? Mention some of the conditions that will impede the oxydation of blood in the lungs. What occurred to those persons who escaped death in the Black Hole of Calcutta? -=-=-=-=-=-=-=-=-=-=-=-= 2d. One of the precursory symptoms of consumption is the feeble murmur of respiration in the upper part of the lungs. This condition of these organs is produced by, or frequently follows, mental depression, the breathing of impure air, the stooping position in standing or sitting, and the restriction of the movements of the ribs and diaphragm. 3d. Persons asphyxiated by carbonic acid, water, strangling, or any noxious air, after resuscitation, are usually affected with coughs and other diseases of the lungs. 537. COLDS and COUGHS are generally induced by a chill, that produces a contraction of the blood-vessels of the skin; and the waste material, which should be carried from the body by the agency of the vessels of this membrane, is retained in the system, and a great portion of it is returned to the mucous membrane of the lungs. For such is the harmony established by the Creator, that if the function of any portion of the body is deranged, those organs whose offices are similar take on an increased action. 538. The waste material, that should have passed through the many outlets of the skin, creates an unusual fulness of the minute vessels that nourish the mucous membrane of the bronchia; this induces an irritation of these vessels, which increases the flow of blood to the nutrient arteries of the lungs. There is, also, a thickening of the lining membrane of the lungs, caused by the repletion of the bronchial vessels of the mucous membrane; this impedes the passage of air through the small bronchial tubes, and consequently the air-vesicles cannot impart a sufficient quantity of oxygen to purify the blood, and this fluid, imperfectly purified, does not pass with facility through the lungs. An additional obstacle to the free passage of air into the lungs, is the accumulation of blood in the pulmonary vessels. -=-=-=-=-=-=-=-=-=-=-=-= What is one of the precursory symptoms of consumption? How is this condition frequently produced? What diseases usually follow asphyxia by carbonic acid, water, strangling, &c.? 537. How are colds generally induced? 538. What effect has a common cold upon the mucous membrane of the lungs? -=-=-=-=-=-=-=-=-=-=-=-= 539. As colds and coughs are very generally treated by the "matrons" of the community, or by the patient, the following suggestions may aid in directing a proper treatment: To effect a speedy cure, it is necessary to diminish the amount of fluid in the vessels of the lungs. This can be effected in two ways: 1st. By diminishing the quantity of blood in the system; 2d. By diverting it from the lungs to the skin. The first condition can be easily and safely affected, by abstaining from food, and drinking no more than a gill of fluid in twenty-four hours. As there is a continuous waste from the skin and other organs of the system, the quantity of blood by this procedure will be diminished, and the lungs relieved of the accumulated fluid. 540. The second condition can be accomplished by resorting to the warm or vapor bath. These and the common sweats will invite the blood from the lungs to the skin. By keeping up the action of the skin for a few hours, the lungs will be relieved. In some instances, emetics and cathartics are necessary; mucilages, as gum arabic or slippery-elm bark, would be good. After the system is relieved, the skin is more impressible to cold, and consequently requires careful protection by clothing. In good constitutions, the first method is preferable, and generally sufficient without any medicine or "sweating." 541. _The method of resuscitating persons apparently drowned._ In the first instance, it is necessary to press the chest, suddenly and forcibly, downward and backward, and instantly discontinue the pressure. Repeat this without intermission, until a pair of bellows can be procured. When the bellows are obtained, introduce the nozzle well upon the base of the tongue, and surround the mouth and nose with a towel or handkerchief, to close them. Let another person press upon the projecting part of the neck, called "Adam's apple," while air is introduced into the lungs through the bellows. Then press upon the chest, to force the air from the lungs, to imitate natural breathing. (Appendix M.) -=-=-=-=-=-=-=-=-=-=-=-= 539. Give the first method for the treatment of cold. 540. The second method. 541, 542. How should persons apparently drowned be treated? -=-=-=-=-=-=-=-=-=-=-=-= 542. Continue the use of the bellows, and forcing the air out of the chest, for an hour at least, unless signs of natural breathing come on. Wrap the body in warm, dry blankets, and place it near the fire, to preserve the natural warmth, as well as to impart artificial heat. Every thing, however, is secondary to filling the lungs with air. Avoid all friction until breathing is restored. Send immediately for medical aid. 543. _The means of resuscitating persons asphyxiated from electricity, &c._ In apparent death from electricity, (lightning,) the person is frequently asphyxiated from _pa-ral´y-sis_ (palsy) of the respiratory muscles. To recover such persons, resort to artificial respiration. In cases of apparent death from hanging or strangling, the knot should be untied or cut immediately; then use artificial respiration, or breathing, as directed in apparent death from drowning. _Observation._ It is an impression, in many sections of the country, that the law will not allow the removal of the cord from the neck of a body found suspended, unless the coroner be present. It is therefore proper to say, that no such delay is necessary, and that no time should be lost in attempting to resuscitate the strangled person. 544. _The method of resuscitating persons apparently dead from inhaling carbonic acid gas._ When life is apparently extinct from breathing carbonic acid gas, the person should be carried into the open air. The head and shoulders should be slightly elevated; the face and chest should be sponged or sprinkled with cold water, or cold vinegar and water, while the limbs are wrapped in dry, warm blankets. In this, as in asphyxia from other causes, immediately resort to artificial respiration. -=-=-=-=-=-=-=-=-=-=-=-= 543. What treatment should be adopted in asphyxia from electricity? From hanging? 544. What should be the treatment in asphyxia from inhaling carbonic acid gas? -=-=-=-=-=-=-=-=-=-=-=-= _Observations._ 1st. Many persons have died from breathing carbonic acid that was formed by burning charcoal in an open pan or portable furnace, for the purpose of warming their, sleeping-rooms. This is not only produced by burning charcoal, but is evolved from the live coals of a wood fire; and being heavier than air, it settles on the floor of the room; and, if there is no open door or chimney-draught, it will accumulate, and, rising above the head of an individual, will cause asphyxia or death. 2d. In resuscitating persons apparently dead from causes already mentioned, if a pair of bellows cannot be procured immediately, let their lungs be inflated by air expelled from the lungs of some person present. To have the expired air as pure as possible, the person should quickly inflate his lungs, and instantly expel the air into those of the asphyxiated person. _Place the patient in pure air, admit attendants only into the apartment, and send for a physician without delay._ -=-=-=-=-=-=-=-=-=-=-=-= What sad results frequently follow the burning of charcoal in a closed room? What suggestion in resuscitating asphyxiated persons? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXVII. ANIMAL HEAT. 545. The true sources of animal heat, or calorification, are still imperfectly known. No hypothesis has, as yet, received the concurrent assent of physiologists. We see certain phenomena, but the ultimate causes are hidden from our view. Its regular production, to a certain degree, is essential both to animal and vegetable life. 546. There is a tendency between bodies of different temperature to an equilibrium of heat. Thus, if we touch or approach a hot body, the heat, or caloric passes from that body to our organs of feeling, and gives the sensation of heat. On the contrary, when we touch a cold body, the heat passes from the hand to that body, and causes a sensation of cold. 547. The greater number of animals appear cold when we touch them; and, indeed, the temperature of their bodies is not much above that of the atmosphere, and changes with it. In man, and other animals that approach him in their organization, it is otherwise. They have the faculty of producing a sufficient quantity of caloric to maintain their temperatures nearly at the same degree, under all atmospheric changes, and keep themselves warm. 548. Those animals whose proper heat is not very perceivable, are called _cold_-blooded; as most species of fishes, toads, snakes, turtles, and reptiles generally. Those animals which produce sufficient heat independently of the atmosphere surrounding them, are called _warm_-blooded; as man, birds, quadrupeds, &c. -=-=-=-=-=-=-=-=-=-=-=-= 545-570. _What is said respecting animal heat?_ 545. Are the true sources of animal heat known? What do we see? 546. What is the tendency between bodies of different temperatures? Give an explanation. 547. What is said of the temperature of animals? 548. What is meant by cold-blooded animals? By warm-blooded animals? -=-=-=-=-=-=-=-=-=-=-=-= 549. The temperature of man is about 98°, (Fahrenheit's thermometer,) and that of some other animals is higher; the temperature of birds, for example, is about 110°. It is obvious, that in most parts of the globe, the heat of the atmosphere is, even in summer, less than that of the human body. In our latitude, the mercury rarely attains 98°, and sometimes it descends to several degrees below zero. 550. Captain Parry, with his ship's company, in his voyage of discovery to the arctic regions, wintered in a climate where the mercury was at 40°, and sometimes at 55° below zero. Captain Back found it 70° below zero. These were 72° and 102° below the freezing point, or about 200° below that of their own bodies, and still they were able to resist this low temperature, and escape being "frost-bitten." 551. Captain Lyon, who accompanied Captain Parry in his second voyage to the northern regions, found the temperature of an arctic fox to be 106°, while that of the atmosphere was 32° below zero; making a difference between the temperature of the fox and that of the atmosphere, of 138°. Captain Scoresby found the temperature of a whale, in the Arctic Ocean, to be 104°, or nearly as high as that of other animals of the same kind in the region of the equator, while the temperature of the ice was as low as 32°, and the water was nearly as cold. These facts show what a strong counteracting energy there is in animals against the effects of cold. 552. On the other hand, it has been ascertained by numerous and well-conducted experiments, that the human body can be exposed, even for a length of time, to a very high temperature, without essentially elevating that of the body. Chantrey, the sculptor, often entered the furnace, heated for drying his moulds, when the temperature indicated by the thermometer was 330°. Chaubert, the Fire-King, is said to have entered ovens when heated to 600°. In 1774, Sir Charles Blagden entered a room in which the mercury rose to 260°. He remained eight minutes without suffering. -=-=-=-=-=-=-=-=-=-=-=-= 549. What is the temperature of the human body? Of birds? How does the heat of the atmosphere in summer, in our latitude, compare with that of the human system? 550. What is related of Captain Parry? Of Captain Back? 551. Of Captain Lyon? Of Captain Scoresby? What do these facts show? 552. What has been ascertained on the other hand? -=-=-=-=-=-=-=-=-=-=-=-= 553. In order to render it certain that there was no fallacy, says Sir Charles Blagden, "in the degree of heat shown by the thermometer, but that the air breathed was capable of producing all the well-known effects of such a heat on inanimate matter, I put some eggs and beefsteak upon a tin frame placed near the thermometer, and farther distant from the cockle than from the wall of the room. In about twenty minutes the eggs were taken out, roasted quite hard; and in forty-seven minutes, the steak was not only dressed, but almost dry." 554. If a thermometer be placed under the tongue of a healthy person, in all climates and seasons the temperature will be found nearly the same. Sir Charles Blagden, "while in the heated room, breathed on a thermometer, and the mercury sank several degrees; and when he expired forcibly, the air felt cool as it passed through the nostrils, though it was scorching hot when it entered them in inspiration." _Observation._ Did not the human body possess within itself the power of generating and removing heat, so as to maintain nearly an equality of temperature, the most fatal consequences would ensue. In northern latitudes, especially, in severe weather of winter, the blood would be converted into a solid mass, and on the other hand, the fatty secretion, when subjected to equatorial heat, would become fluid, and life would be extinguished. -=-=-=-=-=-=-=-=-=-=-=-= What is related of Chantrey? Of Chaubert? Of Sir Charles Blagden? 553. Give Sir Charles's own statement. 554. What is said of the temperature of the human tongue? Mention the experiment by Sir Charles Blagden. What would be the effect if the human system did not maintain an equality of temperature? -=-=-=-=-=-=-=-=-=-=-=-= 555. To enable man, and other warm-blooded animals, to maintain this equilibrium of temperature under such extremes of heat and cold, naturally suggests two inquiries: 1st. By what organs is animal heat generated? 2d. By what means is its uniformity maintained? 556. The ancients had no well-arranged theory on the subject of animal heat. They believed that the chief object of respiration was to cool the blood, and that the heart was the great furnace where all the heat was generated. At a later period, Mayow, from his discoveries respecting respiration, asserted that the object of respiration was to produce heat, and denied that the blood was cooled in the lungs. 557. When it was discovered that, both in combustion and respiration, carbonic acid was produced and oxygen absorbed, it led Dr. Black to conclude that breathing was a kind of combustion by which all the heat of the body was produced. This theory was objected to, because, if all the heat was generated in the lungs, like those parts of a stove in contact with the fuel, they would be at a higher temperature than those parts at a distance, which was known not to exist. 558. The next theory, and one which received the sanction of the scientific men of Europe, was proposed by Dr. Crawford. He agreed with Dr. Black that heat not only was generated in the lungs, but that the arterial blood had a greater capacity for heat than the venous, and that this increase of capacity takes place in the lungs. At the moment heat is generated, a portion of it, under the name of latent heat, is absorbed and conveyed to the different parts of the body Wherever arterial blood is converted into venous, this latent heat is given out. But, unfortunately for this theory, Dr. Davy proved the capacity of both, for heat, to be nearly the same. -=-=-=-=-=-=-=-=-=-=-=-= 555. What inquiries are naturally suggested? 556. What was the theory of the ancients? What did Mayow assert at a later period? 557. What was the theory of Dr. Black? The objection? 558. What was the theory of Dr Crawford? -=-=-=-=-=-=-=-=-=-=-=-= 559. No one can doubt that respiration and animal heat are closely connected. Those animals whose respiratory apparatus is the most extended, have the highest temperature. An example is seen in birds, whose organs of respiration extend over a large part of the body, and their temperature is 12° above man; while the respiratory apparatus of cold-blooded animals, as some kinds of fish, is imperfect, and only a small quantity of blood is subjected, at any time, to the effects of respiration. 560. To understand the process by which heat is generated in the human system and in animals, it will be necessary to state: 1st. That the apparent heat of a body, as perceived by the touch, or as indicated by a thermometer, is not the measurement of heat contained in the body, or its capacity for heat. _Illustration._ If we mix one pound of water, at the temperature of 60°, with another pound at 91°, the resulting temperature will be exactly the medium, or 75½°. But, if we mix a pound of water at 60° with a pound of quicksilver at 91°, the resulting temperature will be only 61°, because the capacity of water for heat is so much greater than that of quicksilver, that the heat which raised the quicksilver 31° will raise the water only 1°. 561. 2d. When the density and the arrangement of the atoms of a body are changed, its capacity to hold heat in a latent state is altered. If it will retain more, heat will be absorbed from contiguous and surrounding substances; but, if its capacity for caloric is lessened, heat will be set free and given out to surrounding bodies. -=-=-=-=-=-=-=-=-=-=-=-= The objection? 559. In what do all the physiologists of the present day concur? How is it proved that respiration and animal heat are closely connected? 560. What is said of the apparent heat of bodies? How is this illustrated? 561. What is the effect when the density and the arrangement of the atoms of a body are changed? -=-=-=-=-=-=-=-=-=-=-=-= _Illustrations._ 1st. Ice and salt, (Chl. of Sodium,) when mixed, are converted into a fluid. In this state they will hold more heat than when solid. The heat necessary to produce this change is drawn from the surrounding medium, which is made proportionally colder by the loss of caloric imparted to the ice and salt. It is by this chemical process that "ice-cream" is made. 2d. On the other hand, mix water and sulphuric acid, (oil of vitriol,) of the temperature of 60°, and the mixture will become quite warm, and will freely impart its heat to surrounding and contiguous objects. 562. The same principle is exhibited, when oxygen unites with an inflammable body, as in the burning of wood, coal, oil, &c. In combustion, the oxygen of the atmosphere unites with carbon and hydrogen, and carbonic acid and water are produced. This process, according to all the known laws of caloric, is attended with heat. The quantity of heat disengaged in combustion is always in proportion to the amount of carbon and hydrogen consumed; thus a piece of wood weighing one pound, in burning slowly, would give out the same quantity of heat as a pound of shavings of the same wood, in burning rapidly. Upon these principles, the production of animal heat may be understood. 563. The food contains carbon and hydrogen. These exist in the chyle. The old and waste atoms of the body likewise contain the same elements. In the lungs the oxygen and nitrogen of the inspired air are separated. It is now supposed that the oxygen enters the capillary vessels of the lungs, and mingles with the blood, with which it is carried to the heart and thence to the nutrient capillary vessels of every part of the system. -=-=-=-=-=-=-=-=-=-=-=-= Give the 1st illustration. The 2d. 562. What changes take place when oxygen unites with an inflammable body? To what is the quantity of heat proportionate in combustion? Give an example. 563. How are carbon and hydrogen supplied to the system? How the oxygen? Where does the oxygen mingle with the blood? -=-=-=-=-=-=-=-=-=-=-=-= 564. In the capillary vessels, the oxygen of the arterial blood unites with the carbon and hydrogen which the refuse materials contain, and carbonic acid and water are formed. The combustion of carbon and hydrogen in the capillaries of every part of the system, (the lungs not excepted,) is attended with a disengagement of heat, and the carbonic acid and water are returned to the lungs in the dark-colored blood, and evolved from the system. 565. Sir Benjamin Brodie and some others have maintained, that the heat of the system is generated exclusively by the influence of the brain and nerves. This theory is discarded by most physiologists; yet it is true that the nervous system exercises a great influence over the action of the capillary vessels in the process of nutrition, secretion, and absorption. When these operations are most active, the change among the particles of matter of which the body is composed, is then greatest, and the generation of heat is increased in a corresponding degree. 566. The necessity of pure, red blood in the production of animal heat, is shown when the vessels that carry blood to a limb are ligated, or tied; the part immediately becomes colder. The necessity of nervous influence is seen in the diminished temperature of a paralytic limb. 567. Our next inquiry is, By what means is the uniformity of temperature in the body maintained? As there is a constant generation of heat in the system, there would be an undue accumulation,--so much so as to cause disagreeable sensations,--if there were no means by which it could be evolved from the body, or its production lessened. -=-=-=-=-=-=-=-=-=-=-=-= 564. Where does it unite with the carbon and hydrogen contained in the body, and how is heat generated? 565. What was the theory of Sir Benjamin Brodie? Is this theory in general discarded? What is true of this theory? 566. How is the necessity of pure, red blood and nervous action shown in the production of animal heat? -=-=-=-=-=-=-=-=-=-=-=-= 568. It has been ascertained that the principal means by which the system is kept at a uniform temperature, is the immense evaporation from the skin and lungs. These membranes, in an ordinary state, are constantly giving out water, which is converted into vapor, and carried off by the surrounding air. The quantity of heat abstracted from the system to effect this, depends on the rapidity of the change of air, its temperature, and the amount of water it contains in a state of vapor. The quantity removed is greatest when the air is warm and dry, and the change, or current, rapid. _Observations._ 1st. The first discovery of the use of free evaporation of the perspiration from the skin in reducing the heat of the body, and the analogy subsisting between this process and that of the evaporation of water from a rough porous surface, so constantly resorted to in warm countries, as an efficacious means of reducing the temperature of the air in rooms, and of wine and other drinks, much below that of the surrounding atmosphere, was made by Franklin. 2d. In all ages and climes, it has been observed that the increased temperature of the skin and system in fevers, is abated as soon as free perspiration is restored. In damp, close weather, as during the sultry days of August, although the temperature is lower, we feel a disagreeable sensation of heat, because the saturation of the air with moisture lessens evaporation, and thus prevents the escape of heat through the lungs and skin. 3d. It is on the principle of the evaporation of fluids that warm vinegar and water, applied to the burning, aching head, cools it, and imparts to it a comfortable feeling. The same results follow if warm liquids are applied to the skin in the hot stage of fever; and this evaporation can be increased by constant fanning. -=-=-=-=-=-=-=-=-=-=-=-= 568. What are the principal means by which a uniform temperature of the body is maintained? On what does the quantity of heat abstracted from the system depend? What discovery relative to animal heat is due to Franklin? What is said of free perspiration in fevers? What occasions the disagreeable sensation of heat in damp, close weather? -=-=-=-=-=-=-=-=-=-=-=-= 4th. It is frequently noticed, in very warm weather, that dogs and other domestic animals are seen with their tongues out of their mouths, and covered with frothy secretions. This is merely another mode of reducing animal heat, as the skin of such animals does not perspire as much as that of man. 569. Under some circumstances, a portion of the heat of the system is removed by radiation. When cold air comes in contact with the skin and mucous membrane of the lungs, heat is removed from the body, as from a stove, to restore an equilibrium of temperature. The removal of heat from the body is greatest when we are in a current of cold air, or when a brisk, cold wind is blowing upon us. 570. As the primary object of the different processes of nutrition is to supply animal heat, so the action of the different nutritive organs is modified by the demands of the system for heat. When heat is rapidly removed from the body, the functional activity of the organs of nutrition is increased. When the system is warmed by foreign influence, the activity of the nutritive organs is diminished. This leads to the natural, and, we may add, instinctive change in the quality and quantity of food at different seasons of the year. -=-=-=-=-=-=-=-=-=-=-=-= 569. When is heat radiated from the body? When is it greatest? 570. What is the primary object of the different processes of nutrition? When is the activity of the nutritive organs increased? When diminished? To what does this lead? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXVIII. HYGIENE OF ANIMAL HEAT. 571. The amount of heat generated in man and inferior animals depends upon the quantity and quality of the food, age, exercise, the amount and character of the respired air, condition of the brain, skin, and general system. 572. _Animal heat is modified by the proportion of digestible carbon which the food contains, and by the quantity consumed._ As the kind of fuel that contains the greatest amount of combustible material evolves the most caloric when burned, so those articles of food that contain the greatest quantity of carbon produce the most heat when converted into blood. The inhabitants of the frigid zones, and individuals in temperate climates during the cold season, consume with impunity stimulating animal food, that contains a large proportion of carbon, while the inhabitants of the tropical regions, and persons in temperate climates during the warm season, are more healthy with a less stimulating or vegetable diet. _Observation._ When we ride or labor in cold weather, an adequate amount of nutritious food will sustain the warmth of the system better than intoxicating drinks. 573. _Age is another influence that modifies the generation of animal heat._ The vital forces of the child being feeble, less heat is generated in its system than in that of an adult. The experiments of Dr. Milne Edwards show that the power of producing heat in warm-blooded animals, is at its minimum at birth, and increases successively to adult age; and that young children part with their heat more readily than adults, and, instead of being warmer, are generally a degree or two colder. After adult age, as the vital powers decline, the generation of heat is diminished, as the energies of the system are lessened. Hence the young child, and the debilitated aged person, need more clothing than the vigorous individual of middle age. -=-=-=-=-=-=-=-=-=-=-=-= 571-585. _Give the hygiene of animal heat._ 571. State some of the influences that modify the generation of animal heat. 572. What element of the food influences the generation of heat? When and where can animal food be eaten with impunity? Give the practical observation. -=-=-=-=-=-=-=-=-=-=-=-= 574. _Exercise is an influence that modifies the generation of animal heat._ As carbon and hydrogen enter into the composition of the organs of the body, whatever increases the flow of blood in the system, increases also the deposition of new material, and the removal of the waste particles. This change among the particles of matter is attended with an elevation of temperature, from the union of oxygen with the carbon and hydrogen of the waste atoms. For this reason, a person in action is warmer than in a quiescent state. Consequently, the amount of clothing should be increased, when exercise or labor is diminished or suspended. 575. On the other hand, whatever impedes the circulation and the interchange of the atoms of matter, diminishes animal heat. Common observation shows, that the extremities are not as warm when tight gloves or boots are worn as when they are loose. One reason is, the circulation of blood is impeded, which is attended with less frequent change of the particles of matter. 576. _The quantity of air which is inhaled modifies the heat of the system._ In the generation of heat in a stove, air, or oxygen, is as essential as the wood or coal. It is equally so in the production of animal heat. The oxygen of the inspired air should be in proportion to the carbon and hydrogen to be consumed. This requires voluminous lungs, together with free movements of the ribs and diaphragm. A person whose chest is small, and whose apparel is worn tight over the ribs, suffers more from the cold, and complains more frequently of chilliness and cold extremities, than the broad-chested and loosely dressed. -=-=-=-=-=-=-=-=-=-=-=-= What do the experiments of Dr. Milne Edwards show? 574. Why does exercise influence animal heat? 575. What is the effect when the circulation of blood is impeded? Give examples. 576. Why do those persons that have broad chests and voluminous lungs suffer less from cold than the narrow-chested with small lungs? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Fishes that breathe by means of gills, as the cod, pike, &c., depend solely on the small quantity of oxygen that is contained in the air mixed with the water. Their temperature is not much greater than the medium in which they live. Whales, dolphins, &c., breathe by means of lungs, and the inhalation of atmospheric air makes their temperature about 100°, independent of the heat of the element in which they live. 577. _The quality of respired air influences the generation of animal heat._ In vestries, and other public rooms, when crowded with an audience, where the ventilation is inadequate, the lamps will emit but a faint light, because the oxygen is soon expended, and there is not enough of the vivifying principle to unite with the oil and disengage light. In the human body, when the respired air has lost some of its life-giving properties, the combustion that takes place in different parts of the system is not so complete as when it contains a proper proportion of oxygen; and hence less heat is disengaged. For this reason, those persons that breathe impure air, either in the daytime or night, require more clothing, than those that work and sleep in well-ventilated rooms. 578. _The condition of the brain and nervous system affects the generation of animal heat._ If the brain is diseased, or the mind is absorbed in thought, depressed by sorrow, or aroused from fear, the breathing becomes slow and scarcely perceptible, and a chilliness pervades the body, particularly the extremities; while, on the contrary, if the mind and nervous system are excited by joyous and agreeable emotions, the circulation of blood is quicker, and the system more powerfully resists external cold. During sleep, when the brain is partially inactive, less heat is generated than when awake. -=-=-=-=-=-=-=-=-=-=-=-= What is said of those fishes that breathe by means of gills? Of those that breathe by means of lungs? 577. Why do lamps give but a faint light in crowded, unventilated rooms? What effect on animal heat has impure air? 578. Mention the effects of some of the mental emotions on animal heat. -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ The preceding remark explains why an individual who sleeps in the same clothing that was adequate to prevent chills while awake, contracts a cold, unless he throws over him an additional covering. 579. _The state of the skin exercises much influence in the generation of heat._ If the functions of this membrane are not interrupted, more heat will be generated than when it is pallid and inactive. The action of the capillaries is most energetic when the skin is clean; on this account, before taking a walk or a ride, in cold weather, remove all impurities from the skin, by thorough ablution and vigorous friction. 580. _The amount and kind of clothing modify the temperature of the system._ Those persons that are well clothed have greater power to resist cold than the thinly apparelled, because both the evaporation and the radiation from the skin are impeded, and less heat, in consequence, is abstracted from the body. If the articles of apparel possess the property of retaining air in their meshes, as flannel, the removal of heat is not as rapid as when linen is worn. _Observation._ In winter, although more heat is generated in the system than in summer, yet we require more clothing, and also those articles that are poor conductors of heat, because caloric is more rapidly extracted in clear, cold weather, than in a warm day. -=-=-=-=-=-=-=-=-=-=-=-= What does the preceding remark explain? 579. What suggestion respecting the condition of the skin before taking a walk or ride in a cold day? Why? 580. Do the amount and kind of clothing affect animal heat? What is said of well-clothed persons? When does the system generate the most heat? -=-=-=-=-=-=-=-=-=-=-=-= 581. _The health and constitution influence the generation of heat._ When the health is firm, and the constitution vigorous, less clothing is needed, for the change among the particles of matter is more rapid, and more heat is generated, than when the opposite condition obtains. Persons of a feeble constitution, particularly, if any of the vital organs[18] are diseased, need more clothing and require rooms of a warmer temperature, than individuals who are free from disease and have a vigorous constitution. [18] The brain, lungs, heart, and digestive organs, are called _vital_ organs. _Observation._ Persons who are infirm, and whose vital powers are feeble, in general, accustom themselves to an undue amount of clothing and warm rooms. A more judicious practice would be, to exercise more and use a moderate amount of clothing, together with a more nutritious diet. 582. _The surplus heat should be removed equally from all parts of the system._ The rapid evaporation of fluids, as in free perspiration, or from radiation, as in a cold atmosphere, is attended with a removal of heat from the system. This modifies the action of the circulatory vessels. Consequently, if heat is suddenly and rapidly abstracted from one part of the system, the equilibrium of the circulation is destroyed, which will produce disease. -=-=-=-=-=-=-=-=-=-=-=-= Why do we, then, require more clothing in winter than in summer? 581. Why do persons of firm health and vigorous constitutions need less clothing than those who are feeble? What is a general practice among infirm persons? What would be more judicious? 582. Why should the surplus heat be removed equally from all parts of the system? What is said respecting currents of air from small apertures? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Currents of air that impinge upon small portions of the body, as from small apertures, or from a window slightly raised, should be avoided. They are more dangerous than to expose the whole person to a brisk wind, because the current of air removes the heat from the part exposed, which disturbs the circulation of blood and causes disease, usually in the form of "colds." For the same reason, it is not judicious to stand in an open door, or the opening of a street. 583. _The system suffers less when the change of temperature is gradual._ The change in the production of heat, as well as in the evaporation of fluids from the system, is gradual when not influenced by foreign causes. This gradual change is known under the name _acclimation_. By this means the body is enabled to endure tropical heat and polar cold. Owing to this gradual adaptation of the system to different temperatures, we can bear a greater degree of heat in the summer between the tropics, than in the winter under the polar circles. On the other hand, we can endure a greater degree of cold in winter and in the arctic region, than in the summer and in equatorial countries. 584. The sensation of heat which would be oppressive in a mild, warm day of January, would only be grateful in July, and a degree of cold which could scarcely be endured in August, would not be uncomfortable in December. The changes of season in our latitude prevent the disagreeable and perhaps fatal consequence that would follow, if no spring or autumn intervened between the severity of winter's cold and the intensity of summer's heat. During the transition periods, the constitution is gradually changed, and adapted to bear the extremes of temperature without suffering. The amount of heat generated in the nutrient capillary vessels, is likewise diminished or increased as the temperature of the season becomes greater or less. -=-=-=-=-=-=-=-=-=-=-=-= 583. In what manner should change of temperature take place, to be adapted to the body? How is the body enabled to endure tropical heat and polar cold? State some of the effects of the gradual adaptation of the system to different temperatures. 584. What is said relative to a warm day in winter? To a cold day in summer? What is said of the changes of seasons in our latitude? What effect on the constitution during spring and autumn? What change in the amount of heat generated? -=-=-=-=-=-=-=-=-=-=-=-= 585. But, on the contrary, we cannot suddenly pass from one extreme of temperature to the other with impunity. Let an inhabitant of Quebec suddenly arrive in Cuba in February, and he would suffer from languor and exhaustion; after becoming acclimated to this tropical climate, let him suddenly return to Quebec in January, and the severity of the weather would be almost insupportable. _Observations._ 1st. Experience shows that heated rooms, as well as tropical climates, lessen the generation of heat in the body, and likewise the power of resisting cold. It would be idle for the merchant from his warehouse, or the mechanic from his heated shop, to attempt to sit on the box with a coachman, with the same amount of clothing as his companion, who is daily exposed to the inclemency of the weather. 2d. "It is the power of endurance of cold at one period, and the absence of its necessity at another, that enables animals, in their wild and unprotected state, to bear the vicissitudes of the seasons with so little preparation in clothing, and so little real inconvenience." -=-=-=-=-=-=-=-=-=-=-=-= 585. What effect on the system has a sudden transition from a cold to a warm climate? What does experience show? Why do wild animals bear the vicissitudes of the seasons with so little preparation in clothing? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXIX. THE VOICE. 586. The beautiful mechanism of the vocal instrument, which produces every variety of sound, from a harsh, unmelodious tone, to a soft, sweet, flute-like sound, has, as yet, been imperfectly imitated by art. It has been compared, by many physiologists, to a wind, reed, and stringed instrument. This inimitable, yet simple instrument, is the _Lar´ynx_. 587. Incidentally, the different parts of the respiratory organs, as well as the larynx, are subservient to speaking and singing. The tongue, nasal passages, muscles of the fauces and face, are agents which aid in the intonation of the voice. ANATOMY OF THE VOCAL ORGANS. 588. The LARYNX is a kind of cartilaginous tube, which, taken as a whole, has the general form of a hollow, reversed cone, with its base upward toward the tongue, in the shape of an expanded triangle. It opens into the pharynx, at its superior extremity, and communicates, by its inferior opening with the trachea. It is formed by the union of five cartilages, namely, the _Thy´roid_, the _Cri´coid_, the two _A-ryt-e´noid_, and the _Ep-i-glot´tis_. These are bound together by ligaments, and moved by muscles. -=-=-=-=-=-=-=-=-=-=-=-= 586. What is said of the structure of the vocal instrument? With what instrument have physiologists compared it? What is the vocal instrument called? 587. What organs are called into action in speaking beside the larynx? 588-596. _Give the anatomy of the vocal organs._ 588. Describe the larynx. Name the cartilages that form the larynx. -=-=-=-=-=-=-=-=-=-=-=-= 589. The THYROID CARTILAGE is the largest of the five, and forms the prominence in the front of the neck, called _Po´mum A-da´mi_, (Adam's apple.) It is composed of two parts, and is connected with the bone of the tongue above, and with the cricoid cartilage below. 590. The CRICOID CARTILAGE takes its name from its resemblance to a ring. It is situated below the thyroid cartilage, it is narrow in front, broader at the sides, and still broader behind, where it is connected with the thyroid cartilage. Below, it connects with the first ring of the trachea. [Illustration: Fig. 102. A side view of the cartilages of the larynx. * The front side of the thyroid cartilage. 1, The os hyoides, (bone at the base of the tongue.) 2, The ligament that connects the hyoid bone and thyroid cartilage. 3, 4, 5, The thyroid cartilage. 6, The cricoid cartilage. 7, The trachea.] [Illustration: Fig. 103. A posterior view of the cartilages and ligaments of the larynx. 1, The posterior face of the epiglottis. 3, 3, The os hyoides. 4, 4, The lateral ligaments which connect the os hyoides and thyroid cartilage. 5, 5, The posterior face of the thyroid cartilage. 6, 6, The arytenoid cartilages. 7, The cricoid cartilage. 8, 8, The junction of the cricoid and the arytenoid cartilages. 12, The first ring of the trachea.] -=-=-=-=-=-=-=-=-=-=-=-= 589. Describe the thyroid cartilage. 590. From what does the cricoid cartilage derive its name? Where is it situated? Explain fig. 102. Fig. 103. -=-=-=-=-=-=-=-=-=-=-=-= 591. The ARYTENOID CARTILAGES are small triangular bodies placed upon the back part of the cricoid cartilage. They are connected with the thyroid cartilages, by four ligaments, called _Vo´cal Cords_. 592. The EPIGLOTTIS is fibro-cartilaginous, and is placed behind the base of the tongue. In shape it resembles a leaf of parsley. 593. The VOCAL CORDS, or ligaments, are formed of elastic and parallel fibres, enclosed in a fold of mucous membrane. They are about two lines in width, and pass from the anterior angle of the thyroid cartilage, to the two arytenoid cartilages. The one is called the superior, and the other the inferior vocal ligament. The cavity, or depression between the superior and inferior ligament, is called the _ventricle_ of the larynx. The aperture, or opening between these ligaments, is called the _glot´tis_, or _chink of the glottis_. It is about three fourths of an inch in length, and one fourth of an inch in width, the opening being widest at the posterior part. This opening is enlarged and contracted by the agency of the muscles appropriated to the larynx. [Illustration: Fig. 104. An ideal, lateral section of the larynx. 1, 1, The upper vocal cords. 2, 2, The lower vocal cords. 3, 3, The glottis. 4, 4, The ventricles of the larynx.] [Illustration: Fig. 105. A vertical section of the larynx. 2, The os hyoides. 4, The apex of the epiglottis. 7, The superior vocal ligament. 9, The ventricle of the larynx. 10. The lower vocal ligament. 11, The arytenoid cartilage. 12, 13, The cricoid cartilage. 14, The trachea. 18, The oesophagus.] -=-=-=-=-=-=-=-=-=-=-=-= 591. Describe the arytenoid cartilages. 592. What is said of the epiglottis? 593. Give the structure of the vocal cords. Where is the ventricle of the larynx? Where is the glottis situated? What is represented by fig. 104? Explain fig. 105. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 106. A view of the larynx from above, showing the vocal ligaments. 1, The anterior edge of the larynx. 4, The posterior face of the thyroid cartilage. 5, 5, The arytenoid cartilages. 6, 6, The vocal ligaments. 7, Their origin, within the angle of the thyroid cartilage. 9, Their termination, at the base of the arytenoid cartilages. 8, 10, The glottis.] 594. The larynx is connected by muscles with the sternum, oesophagus, base of the skull, hyoid bone, lower jaw, and tongue. This organ is supplied with a large number of blood-vessels, and it likewise receives nerves from the sympathetic system, and two large nerves from the tenth pair. The number and size of the nervous filaments distributed to the mucous membrane of the larynx, render it more sensitive than any other portion of the respiratory organs. -=-=-=-=-=-=-=-=-=-=-=-= How is the glottis enlarged or contracted? Explain fig. 106. 594. By what means and to what organs is the larynx connected? Why is the larynx more sensitive than other parts of the respiratory organs? -=-=-=-=-=-=-=-=-=-=-=-= 595. The larynx is much more developed and prominent in man than in woman. In the former, the anterior angle of the thyroid cartilage is acute, while in the latter it is rounded, and the central slope of the superior border of the same cartilage is less deep, and the epiglottis smaller and less prominent, than in man. 596. The difference in the formation of the larynx in infancy is less striking; but at a later period, it is more developed in the male than in the female. It is very remarkable that this increase is not progressive, like that of other organs, but, on the contrary, develops itself at once at the period of puberty. PHYSIOLOGY OF THE VOCAL ORGANS. 597. In the formation of the voice, each part already described performs an important office. The cricoid and thyroid cartilages give form and stability to the larynx; the arytenoid cartilages, by their movement, vary the width of the glottis. The epiglottis is flexible and elastic. When it is erect, the chink of the glottis is open, as in inspiration; when depressed, as in swallowing food and drink, it covers and closes this aperture. It prevents the introduction of articles of food into the trachea, and probably modifies sound as it issues from the glottis. 598. The muscles of the neck elevate and depress the larynx; the muscles of the larynx increase or diminish the width of the glottis; at the same time, the vocal cords are relaxed or tightened, while the muscles of the face open and close the mouth. -=-=-=-=-=-=-=-=-=-=-=-= 595. What difference between the formation of the larynx of the female and that of the male? 596. Does this difference exist in childhood? Is its development progressive? 597-600. _Give the physiology of the vocal organs._ 597. Which cartilages give stability and form to the larynx? Which vary the width of the glottis? What is the function of the epiglottis? 598. What effect have the muscles of the neck upon the larynx? The use of the muscles of the larynx? -=-=-=-=-=-=-=-=-=-=-=-= 599. The elasticity of the ribs and the contraction of the abdominal muscles diminish the cavity of the chest, and the air, in consequence, is pressed from the air-cells into the bronchial tubes and trachea. It then rushes by the vocal cords, and causes a peculiar vibration, which produces _sound_. _Observations._ 1st. Experiments have satisfactorily shown that the vocal cords are the principal agents in the formation of the voice. The tongue, which many have supposed to be the most important organ in speaking, is not essential to sound. In several instances it has been removed, and the persons thus mutilated could speak with fluency. 2d. When the vocal cords are ulcerated, or inflamed, however slightly, as in sore throat produced by a cold, the voice will be changed. The loss of speech among public speakers is generally produced by a relaxation of the vocal ligaments. Hence, bronchitis is a misnomer for this affection. 600. Sound is varied by the velocity of the expelled current of air, and the tension of the vocal ligaments. The size of the larynx, the volume and health of the lungs, the condition of the fauces and nasal passages, the elevation and depression of the chin, the development and freedom of action of the muscles which are attached to the larynx, the opening of the mouth, the state of the mind, and general health of the system, influence the modulations of sound. -=-=-=-=-=-=-=-=-=-=-=-= What effect has the combined action of these muscles? 599. How is sound produced? What have experiments shown? What effect has disease of the vocal ligaments upon the voice? 600. How is sound varied? Mention other conditions that contribute to the modulation of sound. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXX. HYGIENE OF THE VOCAL ORGANS. 601. _The voice can be changed and modified by habit._ Sailors, smiths, and others, who are engaged in noisy occupations, exert their vocal organs more strongly than those of more quiet pursuits. This not only affects the structure of the vocal organs, but varies the intonation of the voice. 602. _The voice is strong in proportion to the development of the larynx, and the capacity of the chest._ Singing and reading aloud improve and strengthen the vocal organs, and give a healthy expansion to the chest. The enunciation of the elementary sounds of the English language, aids in developing the vocal organs, as well as preventing disease of the throat and lungs. This exercise also conduces to the acquisition of musical sounds. 603. _The attitude affects the modulation of the voice._ When an individual stands erect, the movements of the whole respiratory apparatus are most free and effective. The larynx is brought forward by the erect position of the head and the elevation of the chin. The muscles of the arytenoid cartilages are then brought to a proper relation for action, by which a tension of the vocal cords is produced, that favors clear and harmonious enunciation. _Experiment._ Read with the head bowed forward and the chin depressed; then read with the head erect and the chin elevated, and the difference in the movement of the vocal organs, together with the difference in the voice, will be manifest. -=-=-=-=-=-=-=-=-=-=-=-= 601-616. _Give the hygiene of the vocal organs._ 602. How may the voice be strengthened? 603. What effect has the erect attitude upon the modulations of the voice? Give the experiment. -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 107. An improper position; but one not unfrequently seen in some of our common schools, and in some of our public speakers.] [Illustration: Fig. 108. The proper position for reading, speaking, and singing.] 604. If an individual or class read or sing when sitting, let the position represented by fig. 109 be adopted, and not the one represented by fig. 110; for the erect position in sitting conduces to the free and effective action of the respiratory and vocal organs, and is as important as the erect attitude in standing. -=-=-=-=-=-=-=-=-=-=-=-= 604. What position should be adopted when a person reads or sings when sitting? Why? -=-=-=-=-=-=-=-=-=-=-=-= 605. _The muscles of the neck should not be compressed._ If the muscles of the neck and larynx are compressed by a high cravat, or other close dressing, not only will the free and energetic movements of these parts be impeded, but the tones will be feeble and ineffective. Therefore the dress of the neck, particularly of public speakers and singers, should be loose and thin. For a warm dress upon the neck, when the vocal organs are in action, will induce too great a flow of blood to these parts, which will be attended by subsequent debility. [Illustration: Fig. 109.] _Observations._ 1st. The loss of voice, (_lar-yn-gi´tis_,) which is prevalent among public speakers, may be ascribed in part to the injudicious dressing of the neck, and improper position in standing. -=-=-=-=-=-=-=-=-=-=-=-= 605. How should public speakers dress their necks? Why? What is a common cause of the loss of voice? -=-=-=-=-=-=-=-=-=-=-=-= 2d. When individuals have been addressing an audience in a warm room, or engaged in singing, they should avoid all impressions of a cold atmosphere, unless adequately protected by an extra garment. [Illustration: Fig. 110.] 606. _The condition of the air modifies speaking and singing._ As pure air is more elastic and resonant than impure, and as easy, melodious speaking or singing requires atmospheric elasticity, so school-rooms and singing-halls should be well ventilated, if we would be entertained with soft intonations in reading, or sonorous singing. _Observation._ The imperfect ventilation of churches and vestries is another cause of laryngitis among clergymen. This affection is almost unknown among those who speak in very open rooms, where stoves are not used. -=-=-=-=-=-=-=-=-=-=-=-= Give 2d. observation. 606. Why does easy and melodious speaking require pure air? What is another cause laryngitis among clergymen? -=-=-=-=-=-=-=-=-=-=-=-= 607. _The condition of the nasal passages and throat modifies the voice._ The enunciation of words is rendered more or less distinct, in proportion as the jaws are separated in speaking, and the fauces and nasal passages are free from obstruction. For these reasons, the scholar should be taught to open the mouth adequately when reading, speaking, or singing, that the sounds formed in the larynx and modified in the fauces may have an unobstructed egress. _Observations._ 1st. If the fauces are obstructed by enlarged tonsils, (a condition by no means uncommon in children,) they should be removed by a surgical operation, which is not only effective, but safe, and attended with little suffering. The tonsils are situated on each side of the base of the tongue, and, when enlarged, they obstruct the passage through which the air passes to and from the lungs, and the respiration is not only laborious, but distressing. 2d. When the nasal passages are obstructed, there is a peculiar sound of the voice, which is called "talking through the nose." This phenomenon arises, not from the expired air passing through the nose, but from its not being able to pass through the nasal passages. 608. _The state of the mind and health exerts an influence upon the vocal organs._ "The organs of the voice, in common with all other parts of the bodily frame, require the vigor and pliancy of muscle, and the elasticity and animation of mind, which result from good health, in order to perform their appropriate functions with energy and effect. But these indispensable conditions to the exercise of vocal organs, are, in the case of most learners, very imperfectly supplied." -=-=-=-=-=-=-=-=-=-=-=-= 607. Does the condition of the throat and nasal passages modify the voice? Name the influences that produce clear enunciation of words. What is the effect when the nasal passages are obstructed? 608. How are the vocal organs influenced? What do they require? -=-=-=-=-=-=-=-=-=-=-=-= 609. "A sedentary mode of life, the want of invigorating exercise, close and long-continued application of mind, and, perhaps, an impaired state of health, or a feeble constitution, prevent, in many instances, the free and forcible use of those muscles on which voice is dependent. Hence arises the necessity of students of elocution practising physical exercises adapted to promote general muscular vigor, as a means of attaining energy in speaking; the power of any class of muscles being dependent on the vigor of the whole system." 610. "Gymnastic and calisthenic exercises are invaluable aids to the culture and development of the voice, and should be sedulously practised when opportunity renders them accessible. But even a slight degree of physical exercise, in any form adapted to the expansion of the chest and to the freedom and force of the circulation, will serve to impart energy and glow to the muscular apparatus of voice, and clearness to its sound." 611. "There is, therefore, a great advantage in always practising some preliminary muscular actions, as an immediate preparation for vocal exercises. The art of cultivating the voice, however, has, in addition to the various forms of corporeal exercise, practised for the general purpose of promoting health, its own specific prescription for securing the vigor of the vocal organs, and modes of exercise adapted to the training of each class of organs separately." 612. The results of such practice are of indefinite extent. They are limited only by the energy and perseverance of the student, excepting perhaps in some instances of imperfect organization. A few weeks of diligent cultivation are usually sufficient to produce such an effect on the vocal organs, that persons who commence practice with a feeble and ineffective utterance, attain, in that short period, the full command of clear, forcible, and varied tone. -=-=-=-=-=-=-=-=-=-=-=-= 609. Why are students of elocution in general necessitated to practise physical exercise? 610. What are invaluable aids in the culture of the voice? 611. What is said of the art of cultivating the voice? 612. Are the results of such practices limited? What exception? -=-=-=-=-=-=-=-=-=-=-=-= 613. _Repetition is essential to distinct articulation of words._ In teaching a child to articulate a letter or word, in the first instance, make an effort to induce a proper state of the vocal organs by which the particular sound is produced. Repeat the letter or word again and again, until all the parts of the vocal apparatus harmonize in their movements to produce the given sound. This repetition is as necessary in learning to read as in singing. _Observations._ 1st. There is nothing gained by trying to teach a child to pronounce the letters of the alphabet, before the vocal organs are so developed that distinct utterance can be given to the proper sounds. 2d. The drawling method of talking to young children, as well as using words that are not found in any written language, (called child's talk,) is decidedly wrong. A child will pronounce and understand the application of a correct word as quickly as an incorrect one. 614. _No part of the vocal organs is wanting, with those individuals that stammer, or who have an impediment in their speech._ Some parts may be more developed than others, but they generally are but imperfectly under the control of the will, and assume an irregular and rapid movement, while other parts, the motions of which are essential, remain comparatively inactive. This can be seen by comparing the movements of the lips, tongue, and larynx, while attempting to speak, in a person who stammers, with the movements of the corresponding parts, while speaking, in an individual who has no such impediment. -=-=-=-=-=-=-=-=-=-=-=-= 613. Is repetition essential to distinct articulation? What method is suggested in teaching a child to articulate letters or words? Give observation 1st. Observation 2d. 614. Are the vocal organs wanting in stammerers? Why the defect in their articulation of words? -=-=-=-=-=-=-=-=-=-=-=-= 615. Surgical operations and medical treatment are not highly advantageous in a majority of these cases. In the young and middle aged, this defect can be remedied by _patient_ and judicious training. At first, only those letters and words should be spoken that can be articulated with distinctness. Let there be repetition, until the words can be spoken at any time with readiness. Then take for a lesson other words, more difficult to articulate; and pursue a similar process of training and repetition, until every part of the vocal organs can be called into a ready and harmonious action in giving utterance to any word in common use. 616. _The method of removing foreign bodies from the throat._ It is not necessary to ascertain which passage the foreign body is in, for the immediate treatment ought in either case to be the same. Some person should place one hand on the front of the chest of the sufferer, and, with the other, give two or three smart blows upon the back, allowing a few seconds to intervene between them. This treatment will generally be successful, and cause the substance to be violently thrown from the throat. _Observation._ If the foreign body passes into the larynx violent spasmodic coughing immediately succeeds, which continues until it is removed or life is extinct. Such cases demand the prompt opening of the trachea below the larynx by a skilful surgeon. -=-=-=-=-=-=-=-=-=-=-=-= 615. How can stammering be remedied? 616. What is the method of removing foreign bodies from the throat? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXXI. THE SKIN. 617. The skin is a membrane which envelops the muscles and other parts of the system. In youth, and in females particularly, it is smooth, soft, and elastic. In middle age, and in males, it is firm and rough to the touch. In old age, in persons who are emaciated, and about the flexions of the joints, it is thrown into folds. The interior of the body, like the exterior, is covered by a skin, which, from the constantly moistened state of its surface, is called the mucous membrane. At the various orifices of the body, the exterior skin is continuous with the internal. ANATOMY OF THE SKIN. 618. The SKIN, to the naked eye, appears composed of one membrane. But examination has shown that it consists of two layers of membrane, namely, the _Cu´ti-cle_, (scarf-skin,) and the _Cu´tis Ve´ra_, (true skin.) These layers are widely different from each other in structure, and perform very different offices in the animal economy. 619. The CUTICLE (sometimes called the _ep-i-derm´is_) is the external layer of the skin. This membrane is thin and semi-transparent, and resembles a thin shaving of soft, clear horn, and bears the same relation to other parts of the skin that the rough bark of a tree does to the liber, or living bark. The cuticle has no perceptible nerves or blood-vessels; consequently, if it is cut or abraded, no pain will be felt, and no fluid will ooze from it. -=-=-=-=-=-=-=-=-=-=-=-= 617. What is the skin? Mention its different appearances in its different conditions in the human frame. Is the interior of the body, as well as the exterior, covered by a skin? What is the interior membrane called? Why has it received this name? 618-636. _Give the anatomy of the skin._ 618. What is said of the skin? What is said relative to these layers of membrane? 619. Describe the cuticle. What name is sometimes applied to the cuticle? -=-=-=-=-=-=-=-=-=-=-=-= _Experiment._ Pass a pin through the portion of the cuticle that skirts the nails, or remove a thin shaving from the palm of the hand, and no painful sensation will be experienced unless the pin or knife penetrates deeper than the cuticle. 620. This membrane varies in thickness on different parts of the body,--from the thin, delicate skin upon the internal flexions of the joints, to the thickened covering of the soles of the feet. The greater thickness of the cuticle of the palms of the hands and soles of the feet, is manifestly the intentional work of the Creator; for it is perceptible in infants, even at birth, before exercise can have had any influence. 621. The CUTIS VERA (sometimes called the _co´ri-on_) is composed of minute fibres, which are collected into small bundles or strands. These are interwoven with each other so as to constitute a firm, strong, and flexible web. In the superficial part of the true skin, the web is so close as to have the appearance of felt-cloth; but more deeply, the pores become progressively larger, and, upon the lower surface, have a diameter of about a line, or one twelfth of an inch. This gives the under surface the appearance of a coarse web. The strands of the under surface of the true skin are connected with the fibrous web, in which the sub-cutaneous fat of the body is deposited; while the upper surface gives support to the sensitive, or papillary layer, which is bedded upon it. -=-=-=-=-=-=-=-=-=-=-=-= Give the experiment. 620. What is said of the thickness of the cuticle in different parts of the body? 621. Describe the cutis vera. By what name is it sometimes called? What is the appearance of the upper surface of the cutis vera? Of the under surface? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ When the skins of animals are immersed in a strong solution of oak or hemlock bark, a chemical union takes place between the gelatin, of which the true skin is mostly composed, and the tannin of the bark. By this process leather is formed, and its peculiar markings are owing to the papillary layer. [Illustration: Fig. 111. An ideal representation of the papillæ. 1, 1, The cutis vera. 2, 2, The papillary layer. 3, 3, The arteries of the papillæ. 4, 4, The veins of the papillæ. 5, 5, The nerves of the papillæ.] 622. The sensitive layer of the skin is thin, soft, uneven, pinkish in hue, and composed of blood-vessels, which confer its various tints of red; and of nerves, which give it the faculty of sensation. The unevenness of this layer is produced by small, elongated, conical prominences, called _Pa-pil´læ_. 623. Each PAPILLA is composed of a minute artery, vein, and nerve. Some of the prominences are arranged in concentric ovals, as may be seen on the ends of the fingers; others are more or less parallel, and pursue a serpentine course; some suddenly diverge, and again reunite, as may be seen in the palm of the hand. Papillæ are found in every part of the skin. Consequently, their number is very great. -=-=-=-=-=-=-=-=-=-=-=-= How is leather formed? 622. What is the appearance of the sensitive layer? What causes the unevenness of this layer? Explain fig. 111. 623. Describe the papillæ. -=-=-=-=-=-=-=-=-=-=-=-= 624. The cutis vera contains not only _Arteries_, _Veins_, and _Nerves_ but _Lymphatics_, _Oil-Glands_ and _Tubes_, and _Perspiratory Glands_ and _Tubes_. [Illustration: Fig. 112. The arteries and veins of a section of the skin. A, A, Arterial branches. B, B, Capillary, or hair-like vessels, in which the large branches terminate. C, The venous trunk, collecting the blood from the capillaries.] 625. The ARTERIES AND VEINS of the skin are very numerous. The larger branches of the arteries pass through the open meshes of the true skin, and are subdivided into a myriad of minute capillary vessels, which form a beautiful net-work on the upper surface of the true skin. This vascular net sends a branch to each of the papillæ, which opens into and terminates in a minute vein. The capillary veins are as numerous as the arteries which they accompany. They unite and form larger trunks, as small springs from the hill side coalesce to form rivulets. -=-=-=-=-=-=-=-=-=-=-=-= 624. What vessels are found in the cutis vera? Explain fig. 112. 625. What is said of the cutaneous arteries? Of the cutaneous veins? -=-=-=-=-=-=-=-=-=-=-=-= 626. The NERVES that are spread over every part of the sensitive layer of the true skin, proceed from the spinal cord. As a proof of the great number of nervous filaments in the skin, no part of this tissue can be punctured with a fine needle without transfixing a nerve, and inducing pain. In some parts of the system, however, the nerves are more abundant than in others; where the sense of feeling is most acute, we find the greatest number of nerves, and those of the largest size. Those parts that are most exposed to injury are most sensitive. _Examples._ 1st. The conjunctiva, or skin of the eye, is pained by the presence of a particle of dust, because it would render vision imperfect. 2d. The lungs, also, would be injured by the smallest particle of matter; they are therefore protected by the exquisite sensitiveness of the lining membrane of the trachea, so that a particle of food or dust is ejected by a convulsive cough before it reaches the lungs. 627. The nerves are more numerous in the upper than lower extremities; in greater numbers upon the palm than the back of the hand. They are, likewise, more abundant and larger at the extremities of the fingers, and in the lips, than in any other part of the skin. _Observation._ The proboscis of the elephant, the extremities of the tails of certain species of monkeys, and the tentacula of some kinds of fish, receive a more abundant supply of sensitive nerves than other parts of their systems. -=-=-=-=-=-=-=-=-=-=-=-= 626. Where do the nerves of the skin proceed from? Are they numerous in this membrane? How is it proved? What is said of those parts most exposed to injury? Give example 1st. Example 2d. 627. Mention the difference in the distribution of the nerves in various parts of the body. Is this difference found in the lower order of animals? -=-=-=-=-=-=-=-=-=-=-=-= 628. In the small papillæ, the nerve forms a single loop, while in papillæ of larger size, and endowed with a power of more exalted sensation, the nerve is bent several times upon itself previous to completing the loop. These little loops spring from a net-work of nerves, imbedded in the upper porous layer of the true skin, at the base of the papillæ. This net-work of nerves receives its influence through nerves which take their winding course through the fat distended openings of the deeper layers of the true skin. [Illustration: Fig. 113. 1, 1, The cuticle. 2, 2, The colored layer of the cuticle. 3, 3, The papillary layer, exhibiting the nerves as they form loops. 4, 4, The net-work of nerves. 5, 5, The true skin. 6, 6, 6, Three nerves that divide to form the net-work (4, 4.) 7, 7, 7, The furrows between the papillæ. 8, 8, 8, Three papillæ magnified fifty diameters.] 629. The LYMPHATICS are found in great numbers in the true skin, and they are so minute that they cannot be seen with the naked eye; but when these hair-like vessels are injected with quicksilver, (a work of great difficulty,) the surface injected resembles a sheet of silver. In this way their existence can be imperfectly demonstrated. They are a part of the vascular net-work situated upon the upper surface of the true skin. Each papilla is supplied with a lymphatic filament, the mouth of which opens beneath, and lies in contact with the under surface of the cuticle. This net-work of vessels communicates through the open meshes of the true skin with larger lymphatic trunks, that open into the venous system. -=-=-=-=-=-=-=-=-=-=-=-= 628. How are the nerves of the small papillæ arranged? How in the large papillæ? What does fig. 113 represent? 629. What is said of the cutaneous lymphatics? How is their existence proved? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 114. A plexus of lymphatic vessels in the skin, considerably magnified from an injected preparation.] 630. The OIL-GLANDS are small bodies imbedded in the true skin. They connect with the surface of the skin by small tubes, which traverse the cuticle. In some parts, these glands are wanting; in others, where their office is most needful, they are abundant, as on the face and nose, the head, the ears, &c. In some parts, these tubes are spiral; in others, straight. These glands offer every shade of complexity, from the simple, straight tube, to a tube divided into numberless ramifications, and constituting a little rounded tree-like mass, about the size of a millet seed. -=-=-=-=-=-=-=-=-=-=-=-= Of what are they a part? 630. Describe the oil-glands. With what do they connect? Do they exist in every part of the body? Of what form are their tubes? -=-=-=-=-=-=-=-=-=-=-=-= 631. In a few situations, these small glands are worthy of particular notice, as in the eyelids, where they possess great elegance of distribution and form, and open by minute pores along the lids; in the ear-passages, where they produce that amber-colored substance, known as the _ce-ru´men_, (wax of the ears,) and in the scalp, where they resemble small clusters of grapes, and open in pairs into the sheath of the hair, supplying it with a pomatum of Nature's own preparing. The oil-tubes are sometimes called the _se-ba´ceous fol´li-cles_. [Illustration: 4. A small hair from the scalp, with its oil-glands. The glands (A) form a cluster around the shaft of the hair-tube, (C.) These ducts open into the sheath of the hair, (B.) All the figures, from 1 to 4, are magnified thirty-eight diameters.] -=-=-=-=-=-=-=-=-=-=-=-= 631. What is said of these tubes in the eyelids? In the ear? In the scalp? What are these glands sometimes called? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Among the inhabitants of cities, and especially in persons who have a torpid state of the skin, the contents of the oil-tubes become too dense and dry to escape in the usual manner. Thus it collects, distends the tube, and remains until removed by art. When this impacted matter reaches the surface, dust and smoke mix with it, then it is recognized by small, round, dark spots. These are seen on the forehead, nose, and other parts of the face. When this matter is pressed out, the tube gives it a cylindrical form. The parts around the distended tubes sometimes inflame. This constitutes the disease called, _"ac´ne punc-ta´ta."_ 632. The PERSPIRATORY APPARATUS consists of minute cylindrical tubes, which pass inward through the cuticle, and terminate in the deeper meshes of the cutis vera. In their course, each little tube forms a beautiful spiral coil; and, on arriving at its destination, coils upon itself in such a way as to constitute an oval-shaped, or globular ball, called the _perspiratory gland_. 633. The opening of the perspiratory tube on the surface of the cuticle, namely, "the pores," is also deserving of attention. In consequence of its extremity being a section of a spirally-twisted tube, the aperture is oblique in direction, and possesses all the advantages of a valvular opening, preventing the ingress of foreign injurious substances to the interior of the tube and gland. 634. "To arrive at something like an estimate of the value of the perspiratory system, in relation to the rest of the organism, I counted the perspiratory pores on the palm of the hand, and found 3528 in a square inch. Now each of these pores being the aperture of a little tube about a quarter of an inch long, it follows, that in a square inch of skin on the palm of the hand there exists a length of tube equal to 882 inches, or 73½ feet. Surely such an amount of drainage as seventy-three feet in every square inch of skin--assuming this to be the average for the whole body--is something wonderful and the thought naturally intrudes itself, What if this _drainage_ be obstructed? -=-=-=-=-=-=-=-=-=-=-=-= What is said of the retention of the unctuous matter in the oil-tubes? 632. Of what does the perspiratory apparatus consist? 633. What is peculiar in the opening of the perspiratory tubes on the surface of the cuticle? 634. How many perspiratory pores did Dr. Wilson count upon a square inch of skin on the palm of the hand? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 116. A perspiratory gland from the palm of the hand, magnified forty diameters. 1, 1, A twisted tube composing the gland. 2, 2, The two excretory ducts from the gland. These unite to form one spiral tube, that perforates the cuticle, (3,) and opens obliquely on its surface at 4. The gland is imbedded in cells filled with fat, which are seen at 5, 5.] -=-=-=-=-=-=-=-=-=-=-=-= What does fig. 116 represent? -=-=-=-=-=-=-=-=-=-=-=-= 635. "Could we need a stronger argument for enforcing the necessity of attention to the skin? On the pulps of the fingers, where the ridges of the sensitive layer of the true skin are somewhat finer than in the palm of the hand, the number of pores on a square inch a little exceeded that of the palm; and on the heels, where the ridges are coarser, the number of pores on the square inch was 2268, and the length of the tube 567 inches, 47¼ feet. 636. "To obtain an estimate of the length of tube of the perspiratory system of the whole surface of the body, I think that 2800 might be taken as a fair average of the number of pores in the square inch; and consequently, 700, the number of inches in length. _Now, the number of square inches of surface in a man of ordinary height and bulk is 2500; the number of pores, therefore, 7,000,000; and the number of inches of perspiratory tube is 1,750,000; that is, 145,833 feet, or 48,611 yards, or nearly TWENTY-EIGHT miles!_"--_Wilson._ -=-=-=-=-=-=-=-=-=-=-=-= Give other computations in this paragraph. 635. What is said of the number of these pores on the pulp of the fingers? On the heels? 536. What is an average number of pores and length of tube of the whole surface of the body? Give the summary of the number of pores, and number or inches of perspiratory tube. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXXII. PHYSIOLOGY OF THE SKIN. 637. The skin invests the whole of the external surface of the body, following all its prominences and curves, and gives protection to all the organs it encloses, while each of its several parts has a distinct use. 638. The cuticle is insensible, and serves as a sheath of protection to the highly sensitive skin (_cutis vera_) situated beneath it. The latter feels; but the former blunts the impression which occasions feeling. In some situations, the cuticle is so dense and thick, as wholly to exclude ordinary impressions. Of this we see an example in the ends of the fingers, where the hard and dense nail is the cuticle modified for the purpose referred to. Were the nervous tissue of the true skin not thus protected, every sensation would be so acute as to be unpleasant, and contact with external bodies would cause pain. 639. The cuticle, also, prevents disease, by impeding the evaporation of the fluids of the true skin, and the absorption of the poisonous vapors, which necessarily attend various employments. It, however, affords protection to the system only when unbroken, and then, to the greatest degree, when covered with a proper amount of oily secretion from the oil-glands. 640. The cuticle is, originally, a transparent fluid, exuded by the blood-vessels, and distributed as a thin layer on the surface of the true skin. While successive layers are formed on the exterior of the true skin, the external cuticular layers are converted into dry, flattened scales, by the evaporation of their fluid contents. The thickness of the cuticle is formed mainly from these scales. -=-=-=-=-=-=-=-=-=-=-=-= 637-656. _Give the physiology of the skin._ 637. What is said of the skin? 638. Give a function of the cuticle. Does it vary in thickness on different parts of the body? Give examples. 630. Mention another use of the cuticle. 640. What is the cuticle originally? -=-=-=-=-=-=-=-=-=-=-=-= 641. The cuticle is, therefore, undergoing a constant process of formation and growth at its under part, to compensate for the wear that is taking place continually on its surface. A proper thickness of the cuticle is in this manner preserved; the faculty of sensation and that of touch are properly regulated; the places of the little scales, which are continually falling off under the united influence of friction and ablution, are supplied; and an action necessary, not merely to the health of the skin, but to that of the entire body, is established. 642. Whenever the cuticle is exposed to moderate and repeated friction, it becomes thicker and tougher, as may be seen in the cuticle of the lady's finger that plies the needle and in the hard or callous appearance of the hands of farmers masons, and other mechanics. This enables them to handle the utensils and materials used in their vocations without pain or inconvenience. _Observations._ 1st. When the joints of the feet are subjected to moderate and continued pressure or friction, frequently one or more of the papillæ enlarge. This is accompanied with a thickening of the layers of the cuticle, which is termed a "callosity," or "corn." These thickened layers of the cuticle are broad at the top and narrow at the bottom, and the enlarged mass is conical, with the point innermost. When pressed upon by a tight shoe, these sensitive papillæ cause pain. -=-=-=-=-=-=-=-=-=-=-=-= How is the thickness of the cuticle mainly formed? 641. Describe the changes of this membrane. Show the necessity of this constant growth. 642. How does moderate and repeated friction affect the cuticle? Give examples. What is the benefit derived from having the cuticle thus changed? What is the result if the joints of the feet are subjected to moderate and continued pressure? What is the form of a "corn"? -=-=-=-=-=-=-=-=-=-=-=-= 2d. To remove these painful excrescences, take a thick piece of soft leather, somewhat larger than the corn; in the centre punch a hole of the size of the summit of the corn, spread the leather with adhesive plaster, and apply it around the corn. The hole in the leather may be filled with a paste made of soda and soap, on going to bed. In the morning, remove it, and wash with warm water. Repeat this for several successive nights, and the corn will be removed. The only precaution is, not to repeat the application so as to cause pain. 643. Let a person unaccustomed to manual labor, trundle the hand-cart, or row a boat, for several successive hours, and the cuticle upon the palms of the hands, instead of becoming thicker by use, is frequently separated from the subjacent tissues, by an effusion of serum, (water,) thrown out by the vessels of the true skin. Had the friction been moderate, and applied at regular intervals, instead of blisters being formed upon the inside of the hands, material would have been thrown out to form new layers upon the lower surface of the cuticle. 644. The cuticle is interesting to us in another point of view, as being the seat of the color of the skin. The difference of color between the blonde and the brunette, the European and the African, lies in the cuticle;--in the deeper, and softer, and newly-formed layers of that structure. In the whitest skin, the cells of the cuticle always contain more or less of a peculiar pigment, incorporated with the elementary granules which enter into their composition. In the white races, the pigmentary tint is extremely slight, and less in winter than in the summer season. In the darker races, on the contrary, it is deep and strongly marked. -=-=-=-=-=-=-=-=-=-=-=-= How can they be removed? What precaution is given? 643. Explain why those persons unaccustomed to labor, blister their hands in rowing a boat or performing ordinary manual employment for several successive hours. 644. In what other point of view is the cuticle interesting? In what part of it do we find the coloring matter? -=-=-=-=-=-=-=-=-=-=-=-= 645. The various tints of color exhibited by mankind, are, therefore, referable to the amount of coloring principle contained within the elementary granules of the cuticle, and their consequent depth of hue. In the negro, the granules are more or less black; in the European of the south, they are amber-colored; and in the inhabitants of the north, they are pale and almost colorless. 646. Color of the skin has relation to energy in its action; thus, in the equatorial region, where light and heat are most powerful, the skin is stimulated by these agents to vigorous action, and color is very deep; while in the temperate regions, where light and heat are not so intense, the lungs, liver, and kidneys relieve the skin of part of its duties. The colored layer of the cuticle has been called the _re´te mu-co´sum_, (mucous coat of the skin,) and described as a distinct layer by many physiologists. _Observation._ "The various coloring of the inner layer of the cuticle gives to some animals their varied hues; the serpent, the frog, the lizard, and some fishes have a splendor of hue almost equal to polished metal. The gold-fish and the dolphin owe their difference of color and the brilliancy of their hues to the color of this layer of the skin." 647. The nerves of the skin are the organs of the sense of touch and feeling. Through them we receive many impressions that enhance our pleasures, as the grateful sensations imparted by the cooling breeze in a warm day. In consequence of their sensitiveness, we are individually protected, by being admonished of the proximity of destructive agents. -=-=-=-=-=-=-=-=-=-=-=-= In what season of the year is the coloring matter less in the white race? 645. To what is the color of the skin referable? 646. Why have the races of the torrid zone darker complexions than those of the temperate or frigid zones? What is this colored layer called by many physiologists? To what is the different hues in animals owing? 647. Of what use are the nerves of the skin? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ A man who had been afflicted some years with a severe disease of a portion of the brain and spinal cord, was deprived of feeling in the lower extremities. He was directed by his attending physician to use a warm footbath. Intending to follow the directions given him, he immersed his feet in boiling water, which he supposed of a proper temperature. While his feet were immersed in the water, he experienced no sensation of an unpleasant nature. On withdrawing them, he was astonished to find the cuticle separated from the other tissues, by the effusion of serum, and thus producing a blister over the whole surface. 648. Portions of the skin would suffer every day, were it not for the sentinel-like care exercised by the nerves, by which all impressions are transmitted to the brain. As the skin is continually exposed to the influence of destructive agents, it is important that the nerves, provided for its protection, should be kept in a healthy state. 649. A large proportion of the waste of the body passes through the outlets of the skin; some portions in the form of oil, others in the form of water and carbonic acid. 650. The oil-glands secrete an oil, partly free and diffused, and partly mixed with albumen. When the cells are fully formed, that is, fully distended, they yield their contents, and the fluid matter they contain is set free, and passes along the tubes to the surface; this fluid matter constitutes the oily element of the economy of the skin. 651. The uses of the unctuous product of the oil-glands are twofold: 1st. The protection; 2d. The removal of waste matter from the system. In the exercise of these offices the oily substance is diffused over those parts of the skin which are naturally exposed to vicissitudes of temperature and moisture,--as the nose, face, and head;--to the injurious attrition of contiguous surfaces,--as the flexures of joints;--or the contact of acrid fluids,--as in the excoriations to which infants are liable. -=-=-=-=-=-=-=-=-=-=-=-= Give the illustration. 648. Why is it necessary that the cutaneous nerves be kept in a healthy state? 649. Through what membrane does a large proportion of the waste material of the system pass? 650. What is the function of the oil-glands? 651. What are the uses of the oily product of these glands? -=-=-=-=-=-=-=-=-=-=-=-= 652. The oil of the unctuous substance is the principal agent in effecting these purposes: 1st. It prevents the evaporation or congelation of the water of the cuticle, which would cause it to become parched and peel off, thus leaving the sensitive skin exposed. 2d. It affords a soft medium to the contact of moving substances. 3d. It repels moisture and fluids. 4th. The action of these glands removes the waste atoms and purifies the blood. 653. In considering the purpose of the oily matter of the skin, there are two situations in which it deserves especial remark. 1st. Along the edges of the eyelids, where it is poured out in considerable quantity. Here, it is the means of confining the tears and moisture of the eyes within the lids, defending the skin from the irritation of that fluid, and preventing the adhesion of the lids, which is liable to occur upon slight inflammation. 2d. In the ears, where the unctuous wax not only preserves the membrane of the drum and the passage of the ear moist, but also, by its bitterness, prevents the intrusion of small insects. 654. The use of the perspiratory glands is to separate from the blood that portion of the waste matter which is carried off through the skin in the form of vapor. Sanctorius, a celebrated medical writer, daily, for thirty years, weighed himself, his food, and excretions. He estimated that _five_ of every _eight_ pounds of food and drink passed from the system through the many outlets upon the skin. Many place the estimate much lower. All physiologists agree that from twenty to forty ounces of matter pass off from the skin of an adult every twenty-four hours. -=-=-=-=-=-=-=-=-=-=-=-= 652. What prevents the evaporation of the water of the cuticle? Give its 2d use. Its 3d. Its 4th. 653. What is said in reference to the distribution of the oily matter along the edges of the eyelids? In the ears? 654. Of what use are the perspiratory glands? How long did Sanctorius daily weigh his food, to ascertain the amount of secretion that passed through the skin? -=-=-=-=-=-=-=-=-=-=-=-= 655. The average amount of perspiration is about thirty ounces; and it passes off in such minute portions, and mixes so rapidly with the surrounding air, that it is not perceived. For this reason, it is called _insensible_ perspiration. When this excretion is increased, it forms into drops, and is called _sensible_ perspiration. The following experiments prove the existence of this excretion from the skin. _Experiments._ 1st. Take a cold bell-glass, or any glass vessel large enough to admit the hand, and introduce it perfectly dry; at the same time close the mouth by winding a napkin about the wrist; in a short time, the insensible perspiration from the hand, will be seen deposited on the inside of the glass. At first, the deposit is in the form of mist; but, if the experiment be continued a sufficient time, it will collect in drops. 2d. Hold the apparently dry hand near a looking-glass, and the invisible vapor will soon be condensed, and cover the glass with a slight dew. 656. It is important that this excretion be maintained with steadiness and regularity. When the action of the perspiratory glands is suppressed, all the vessels of the different organs will suffer materially, and become diseased, by the redundant waste matter that should be carried from the system. If a person is vigorous, the action of the organs, whose functions are similar to those of the skin, as channels for the exit of waste matter, will be increased, and thus relieve the diseased state of the body. But the over-taxing of these organs, to relieve the system, often produces a diseased action in themselves. -=-=-=-=-=-=-=-=-=-=-=-= What were his conclusions? 655. What is the average amount of perspiration every twenty-four hours? What is insensible perspiration? What is sensible perspiration? How can the existence of the excretion of the skin be shown? Give the 2d experiment. 656. Why is it important that these excretions be maintained regularly? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 117. 1, 1, The lines, or ridges of the cuticle, cut perpendicularly. 2, 2, 2, 2, 2, The furrows, or wrinkles of the same. 3, The cuticle. 4, 4, 4, The colored layer of the cuticle. 5, 5, The cutis vera. 6, 6, 6, 6, 6, The papillæ. 7, 7, Small furrows between the papillæ. 8, 8, 8, 8, The deeper furrows between each couple of the papillæ. 9, 9, Cells filled with fat. 10, 10, 10, The adipose layer, with numerous fat vesicles. 11, 11, 11, Cellular fibres of the adipose tissue. 12, Two hairs. 13, A perspiratory gland, with its spiral duct. 14, Another perspiratory gland, with a duct less spiral. 15, 15, Oil-glands with ducts opening into the sheath of the hair, (12.)] _Note._--Let the pupil review the anatomy and physiology of the skin from Fig. 117 or from anatomical outline plate No. 9. CHAPTER XXXIII. HYGIENE OF THE SKIN. 657. The sensibility of the skin, and the activity of the oil and perspiratory glands, are modified by the condition of the cuticle, the temperature of the skin and body, the purity and warmth of the air, and the character of the light to which the body is exposed. Thus, to maintain a healthy action of every part of this membrane, attention should be given to _Clothing_, _Bathing_, _Light_, and _Air_. 658. CLOTHING, in itself, does not bestow heat, but is chiefly useful in preventing the escape of heat from the body, and in defending it from the temperature of the atmosphere. In selecting and applying clothing to our persons, the following suggestions should be observed. 659. _The material for clothing should be a bad conductor of heat_; that is, it should have little tendency to conduct or remove heat from the body. This depends mainly on the property possessed by the material in retaining atmospheric air in its meshes. 660. _The material for clothing should not possess the property of absorbing and retaining moisture._ Dampness, or moisture, renders apparel a good conductor of heat; beside, if the perspired fluid, and the saline material it holds in solution, are readily absorbed by the clothing, they become sources of irritation to the skin with which the apparel comes in contact. -=-=-=-=-=-=-=-=-=-=-=-= 657-716. Give the hygiene of the skin. 657. What influences modify the action of the oil and perspiratory glands? To what must attention be given to maintain a healthy action of the skin? 658. What is said in regard to the clothing? 659. Mention a property that the material for clothing should possess. 660. What property in the selection of clothing should we avoid? Why? -=-=-=-=-=-=-=-=-=-=-=-= 661. _Furs_ contain a greater amount of air in their meshes, than any other article, and they absorb no moisture; consequently, as an article of dress, they are best adapted to those who are exposed to great vicissitudes of heat and cold. 662. _Woollen cloth_ retains more air in its meshes than any other article except furs and eider down, and it absorbs but very little moisture. These properties, together with its comparative cheapness, render it a good article of apparel for all classes of persons. The only objection to its general use is, the disturbance of the electricity of the system, and the irritation to delicate skins from the roughness of its fibres. _Observation._ Flannels are not only beneficial, during the cold season, in preventing colds and rheumatism, but they are of great utility in the warm season, in shielding the system from the chills at evening, that induce disease of the alimentary canal. Their general use among children and delicate females, would be a preventive of the "season complaints" prevalent in the months of August and September. 663. _Cotton_ contains less air in its meshes than woollen, but much more than linen. In texture, it is smoother than wool, and less liable to irritate the skin. This fabric absorbs moisture in a small degree. In all respects, it is well adapted for garments worn next the skin. When woollen flannels irritate the skin, they may be lined with cotton. 664. _Silk_ is not as good a conductor of heat as cotton, nor does it absorb moisture to any considerable degree; its texture is smooth, and does not irritate the skin; consequently, when the garment of this fabric has sufficient body or thickness, it is a good article for clothing. The greatest objection to its use is the disturbance of the electricity of the system, and its high price. -=-=-=-=-=-=-=-=-=-=-=-= 661. Give the properties of fur. As an article of dress, to whom are they best adapted? 662. Give the properties of woollen cloth. Is this a good article for clothing? What objection? What are the advantages of wearing flannels? 663. What are the qualities of cotton as an article of dress? 664. Of silk? -=-=-=-=-=-=-=-=-=-=-=-= 665. _Linen_ is not only a good conductor of heat, and consequently a poor article of apparel, but it likewise absorbs the fluids carried from the system by the agency of the oil and perspiratory glands. When garments are made of this material, the body is not surrounded by a layer of air, but by one of moisture. This still further increases its power to conduct heat from the system, rendering it a very objectionable article of apparel, even in warm weather and in hot climates, where the dress is usually thin. 666. _Clothing differs in its power of radiating heat._ This is influenced by the color; those articles that radiate heat freely also absorb it readily. A black surface is a good radiator, while a white surface is not, because it reflects the calorific rays. It is obvious that those colors which render the transmission of external heat difficult, must impede the transmission of caloric from the body. Thus it is manifest, that light-colored apparel is best adapted for every season and every climate. _Observation._ Coach-drivers are practically aware, that in cold weather, light-colored over-coats are warmest, except when they are exposed to the direct rays of the sun, or when seated before a warm fire. On the other hand, when the temperature is elevated, light-colored apparel is coolest, because the sun's rays are then reflected. 667. _The clothing should be of a porous character._ The skin is not only an important agent in separating from the blood those impurities that otherwise would oppress the system and occasion death, but it exercises great influence upon the system, by receiving oxygen through its tissues, and giving back carbonic acid in return. Consequently, the apparel should be made of a material that will permit free transpiration from the skin, and likewise convey the excreted fluids from the surface. -=-=-=-=-=-=-=-=-=-=-=-= 665. What is said of linen as an article of apparel? 666. Why is light-colored apparel best adapted for every season? What is said of the apparel of coach-drivers? 667. Why should we wear porous clothing? -=-=-=-=-=-=-=-=-=-=-=-= 668. The necessity for this is illustrated in wearing India rubber over-shoes. If they are worn over boots ten or twelve hours, not only the hose, but the boots will be moist from retained perspiration, and the residual matter left in contact with the skin may be reconveyed into the system by absorption, causing headache and other diseases. Cotton and woollen fabrics are not only bad conductors of heat, but are also porous; for these reasons, they are well adapted to transmit the excretions of the skin. 669. _The clothing should be not only porous, but fitted loosely._ The garments should retain a layer of air between them and the body. Every one is practically aware that a loose dress is much warmer than one which fits closely; that a loose glove is warmer than a tight one; and that a loose boot or shoe affords greater warmth than one of smaller dimensions. The explanation is obvious; the loose dress encloses a thin layer of air, which the tight dress is incapable of doing; and what is required, is, that the dress should be closed at the upper part, to prevent the dispersion of the warm air, by the ventilating current which would be established from below. _Observation._ As the purpose of additional garments is to maintain a series of strata of warm air within our clothing, we should, in going from a warm room into the cold air, put on our defensive coverings some little time previous, in order that the layers of air which we carry with us may be sufficiently warmed by the heat of the room, and not borrowed from the body on exposure to the cold. -=-=-=-=-=-=-=-=-=-=-=-= 668. How is the necessity of porous clothing illustrated? 669. Why should we wear loose garments? What is the use of additional garments when going from a warm to a cold air? When should they be put on? -=-=-=-=-=-=-=-=-=-=-=-= 670. _The clothing should be suited to the temperature of the atmosphere and the condition of the individual._ The invariable rule should be, to wear enough to maintain an equal and healthy action of the skin. Care should be taken, however, that the action of the cutaneous vessels is not inordinately increased, as this would debilitate, not only the skin, but the internal organs of the system, as the stomach and lungs. 671. No rule as to the quantity of clothing can be given, as the demand will vary with different individuals. The following are among the most prominent causes of this variation: Those persons who have large, active brains, full chests, well developed lungs, breathe an adequate amount of pure air, and take sufficient food to supply the wants of the system, require less clothing than those of an opposite character, because more heat is generated in the system. 672. _The child and the aged person require more clothing than the vigorous adult._ "Should we judge from observation, the inference would be, that children require less clothing than adults. This is an error, for the temperature in infancy is not only lower than in manhood, but the power of creating heat is feebler. The same remarks are applicable to those persons who have outlived the energies of adult life." _Observation._ The system of "hardening" children, by an inadequate supply of clothing, and keeping them uncomfortably cold throughout the whole day, is inhuman, as well as unprofitable. It operates upon the child somewhat like the long-continued chill upon a certain portion of the farmer's herd, that are kept shivering under the thatched shed, retarding the growth of their systems, which require more food to satisfy the keen cravings of hunger than when they are comfortably sheltered. To make the boy robust and active, he must have nutritious food at stated hours, and free exercise in the open air, and his system must be guarded from chills by a due amount of apparel. -=-=-=-=-=-=-=-=-=-=-=-= 670. What should be the invariable rule in reference to the amount of clothing that should be worn? What precaution should be observed? 671. What are some of the causes of the variation of the demand for clothing? 672. Why do the child and aged person require more clothing than the vigorous adult? What is said of the system of hardening children? -=-=-=-=-=-=-=-=-=-=-=-= 673. _More clothing is needed when a vital organ is diseased._ It may be observed that in consumption, dyspepsia, and even in headache, the skin is pale and the extremities cold, because less heat is generated. Thus persons affected with these complaints, when exposed to cold air, need more clothing than those individuals whose organs are not diseased, and the functions of which are properly performed. 674. _More clothing is required in the evening, than during the day._ In the evening we have less vital energy, and therefore less heat is generated in the system, than in the early part of the day; beside, the atmosphere is damp, the skin has become moist from free perspiration, and heat, in consequence, is rapidly removed from the system. For this reason, when returning from crowded assemblies, we should be provided with an extra garment. _Observations._ 1st. If there is a chill upon the system after having arrived home, warmth should be restored as speedily as possible. This can be done by friction with warm flannels, and by using the warm or vapor bath. By this procedure, the pernicious effects of the chill will be prevented before any disease is fixed upon the system. Is it not the duty of the parent and the guardian to learn these facts, and to see that they are not only learned, but reduced to practice? 2d. The farmer and industrious mechanic would be freed from many a rheumatic pain, if, while resting from their labors at evening, or taking the ordinary meal after hard toil, they would put on an extra garment. The coat might not feel so agreeable for the first few minutes, but it would ultimately conduce to health and longevity. -=-=-=-=-=-=-=-=-=-=-=-= 673. Why do dyspeptic and consumptive persons require more clothing than those who have healthy vital organs? 674. Why do we need more clothing in the evening than during the day? How can the pernicious effects of a chill be prevented? Give the 2d observation. -=-=-=-=-=-=-=-=-=-=-=-= 675. _The person of active habits requires less clothing than one of sedentary employments._ Exercise increases the circulation of the blood, which is always attended by the disengagement of a greater quantity of heat; consequently, an increase of warmth is felt throughout the system. We likewise need more clothing while riding, than when we are walking; because the exercise of the former is less than that of the latter. The same is true when resting in the field or shop, after laborious exercise. _Observation._ We need a greater amount of clothing while asleep, than during the day; as not only the action of the body, but that of the brain, during sleep, is suspended. 676. _Less clothing is required when the cutaneous surface is clean._ A film of impurities obstructs the perspiratory ducts, and diminishes the action of their glands; consequently, less heat is generated. For this reason, the hands or feet when clean are less liable to become chilled or frozen. 677. _The sensitiveness of the skin to the influence of cold, is much modified by habit._ A person who has been habituated to the temperature of a warm room, or warm climate, suffers more when exposed to cold, than an individual who has been accustomed to colder air. Thus a person who labors or studies in a warm room, should wear more clothing when exposed to the air, while walking or riding, than an individual who labors in a cooler atmosphere. Not only is the sensibility of the skin increased by a warm atmosphere, but the activity of the digestive, respiratory, and nervous systems, in generating heat, is much diminished. This is an additional reason why an increased amount of clothing is demanded during exposure to cold air. In all cases where practicable the heat of the system should be maintained by exercise, in preference to the use of fur or flannel. -=-=-=-=-=-=-=-=-=-=-=-= 675. Why does the person of active habits require less clothing than one of sedentary employments? 676. Why do we need less clothing when the skin is clean? 677. Show the effect of habit on the sensitiveness of the skin. -=-=-=-=-=-=-=-=-=-=-=-= 678. _Those parts of the skin usually covered, uniformly need that protection._ The power of generating heat is diminished, and the impressibility to cold is increased, on those portions of the skin usually clothed. If a person wears the dress high and close about the neck, he suffers from exposure to a cold atmosphere if a dress is worn that is not as high or more open. As a general rule, it is preferable that those parts of the system, as the larynx, be exposed that are not uniformly protected by clothing. 679. _The clothing should be kept clean._ No article of apparel is entirely free from absorption; even wool and cotton possess it in a small degree. They take up a portion of the transpired fluids which contain saline and animal matter, and thus the fibres of the garments become covered with the cutaneous excretions. We are practically aware of the retention of these secretions from the soiled appearance of those garments worn next the skin, which are so covered as to preclude the particles of dust from lodging upon them. 680. The porosity of the clothing is lessened when soiled, and its power of conducting heat from the system in consequence, is increased. The residual matter with which the clothing is coated is brought in contact with the skin, which causes irritation, and not unfrequently re-absorption of the elements, thrown off from the system through this avenue. Hence warmth, cleanliness, and health require that the clothing, particularly the garments worn next to the skin, should be frequently and thoroughly washed. This should not be forgotten in regard to children, for their blood circulates with greater rapidity than that of adults, and a proportionably greater amount of waste matter is thrown off from their systems. 681. _The under-garments worn during the day should not be worn at night, or the reverse._ When under-garments are worn several successive days or nights, they should not be put in drawers, or hung up in a close closet, as soon as taken from the body, but should be exposed to a current of air. 682. _Occupied beds should be thoroughly aired in the morning._ The excretions from the skin are most abundant during the hours of sleep; and if the sheets and blankets, together with the bed, are not aired every morning, by being so arranged that both surfaces may be exposed to the air, the materials eliminated from the skin will be retained in the meshes of the bed-clothing, and may be conveyed into the system of the next occupant, by absorption. Oftentimes diseases of a disagreeable nature are contracted in this way. This fact should be instilled into every mother's and daughter's mind. _Observation._ Bed-linen should not be put on a bed when it is not sufficiently dried, or contains moisture from the excretions of the skin, nor should beds or bedding be slept in, that have remained in a damp room that has not been occupied for many weeks, unless the dampness is removed from the bed-linen by a warming-pan, or in some other way. 683. _Changes of dress, from thick to thin, should always be made in the morning._ At this time the vital powers are usually in full play. Many a young lady has laid the foundation of a fatal disease, by disregarding this rule, in exchanging the thick dress, with woollen stockings, for the flimsy dress and hose of silk or cotton, which are considered suitable for the ball-room or party. Sudden changes in wearing-apparel, as well as in food and general habits, are attended with hazard; and this is proportionate to the weakness or exhaustion of the system when the change is made. -=-=-=-=-=-=-=-=-=-=-=-= 681. Should the garments worn during the day be worn at night? 682. What is said respecting the cleanliness of beds and bedding? Why should not bed-linen that is damp be slept in? 683. When should change of dress from thick to thin be made? Why? -=-=-=-=-=-=-=-=-=-=-=-= 684. _When the clothing has become wet, it is best to change it immediately._ The skin should then be rubbed with a dry crash towel, until reaction, indicated by redness, is produced. If the garments are not changed, the person should exercise moderately, so that sufficient heat may continue to be generated in the system to dry the clothing and skin without a chill. Sitting in a cool shade, or current of air, should, by all means, be avoided; as colds are not contracted by free and excessive exercise, but by injudicious management after such exercise. _Observation._ When an individual has been thrown into a profuse perspiration by violent exercise, though the skin and clothing may become wet, he feels no inconvenience from the dampness, as long as he continues that amount of exercise for the reason that the circulation of the blood being increased heat is generated in sufficient quantity to replace the amount abstracted from the system in evaporating the free perspiration; but as soon as the exercise is discontinued, the increased circulation subsides, and with it the extra amount of generated heat. This accounts for the chill we experience, when the damp clothing is permitted to dry on the body, after the cessation of exercise. -=-=-=-=-=-=-=-=-=-=-=-= 684. What suggestion when the clothing has become wet? What should be done if the garments are not changed? What causes the chill that is experienced when damp clothing is permitted to dry on the body? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXXIV. HYGIENE OF THE SKIN, CONTINUED. 685. Bathing, its necessity and expediency, is obvious from the structure and the functions of the skin. The cuticle is cast off in minute, powdery scales, many of which are retained upon the surface by the pressure of clothing. These mingle with the oily and saline products of the skin, and form a thin crust. This crust, on account of its adhesiveness, collects particles of dust and soot from the atmosphere, and particles of foreign matter from our dress; so that in the course of the day the whole body becomes coated with impurities. If this coating remains, becomes thick and established upon the skin, it will produce the following effects:-- 686. 1st. _The pores will be obstructed, consequently transpiration impeded, and the influence of the skin as an excretory entirely prevented._ When the pores are obstructed, and transpiration is checked, the elements of the transpired fluids will necessarily be retained in the system; and, as they are injurious and poisonous if retained, they must be removed by those organs whose functions in the animal economy are similar, as the lungs, kidneys, liver, intestines, &c. 687. When these organs are called upon to perform their offices, and in addition that of another, the healthy equilibrium is destroyed, and the oppressed organ will suffer from exhaustion, and become the prey of disease. Thus, obviously, habits of uncleanliness are a cause of consumption and other serious diseases of the vital organs. Again, obstruction of the pores will prevent respiration through the skin, thus depriving the blood of one source of its oxygen, and one outlet of its carbonic acid, which will diminish the temperature of the system, and the same results follow as when the clothing is inadequate. -=-=-=-=-=-=-=-=-=-=-=-= 685. Show the necessity for bathing. 686. What effect upon the body if the pores of the skin are obstructed? 687. What is the effect when an organ not only performs its own specific function, but that of another? -=-=-=-=-=-=-=-=-=-=-=-= 688. 2d. _The retained perspirable matter will irritate the skin, both mechanically and chemically_; and this membrane will be kept damp and cold, from attraction and detention of moisture; and foreign material, as before adverted to, once removed from the system, may be reconveyed into it by absorption. As a consequence, cutaneous eruptions and diseases will be produced, and the re-absorption of matter once separated from the system, will be the exciting cause of other injurious disorders. 689. 3d. _A film of foreign substance on the skin will inevitably become the seat of detention of miasmata and infectious vapors._ These will remain until absorbed, and engender the diseases of which they are the peculiar cause. This is one reason why filthy persons contract infectious diseases more frequently than individuals of cleanly habits. 690. _Bathing is useful to promote cleanliness._ In this capacity, it enables us to remove the coating of impurities from the exterior of our persons. It effects this purpose by dissolving saline matters, and holding in temporary suspension those substances which are insoluble. 691. The cuticle is composed of a substance resembling the dried white of egg, or, in a word, _albumen_. This is soluble in alkalies, and these are the agents which are commonly employed for purifying the skin. Soap is a compound of the alkali soda with oil, the former being in excess. When used for washing, the excess of alkali combining with the oily fluid, with which the skin is naturally bedewed, removes it, in the form of an emulsion, and with it a portion of any adhering matter. Another portion of the alkali softens and dissolves the superficial layer of the cuticle; and when this is removed the cuticle is free from impurities. -=-=-=-=-=-=-=-=-=-=-=-= 688. How are cutaneous eruptions frequently produced? 689. How are infectious vapors transmitted to the system? 690. How does bathing promote cleanliness? 691. Why is it necessary to use soap in bathing? -=-=-=-=-=-=-=-=-=-=-=-= 692. Every washing of the skin with soap removes the old face of the cuticle, and leaves a new one; and were the process repeated to excess, the latter would become so thin as to render the body sensible to impressions too slight to be felt through its ordinary thickness. On the other hand, when the cuticle and its accumulated impurities are rarely disturbed, the sensitiveness of the skin is impaired. The proper inference to be drawn from the preceding remarks, is in favor of the _moderate_ use of soap to cleanse the skin. _Observation._ If any unpleasant sensations are felt after the use of soap, they may be immediately removed by washing the surface with water slightly acidulated with lemon juice or vinegar, which neutralizes the alkali that may remain on the skin. This is effective treatment for "chapped hands." 693. _Bathing may be partial or general, and the water used may be cold, temperate, tepid, warm, or hot._ A person may apply it to his system with a sponge, it may be poured upon him, or he may immerse himself in it. The simplest mode of bathing is to apply water to a small extent of surface, by means of a wet sponge, and after being wiped dry, again cover with the dress. In this way the whole body may be speedily subjected to the influence of water, and to no less useful friction. The water used may be warm or cold. This species of bathing may be practised by any invalid, and always with benefit, if the bathing is succeeded by a glow of warmth over the surface; and this is the test by which the benefit of all forms of bathing is to be estimated. -=-=-=-=-=-=-=-=-=-=-=-= 692. Why should only a moderate amount of soap be used in bathing? If unpleasant sensations are felt from too free use of soap, how can they be counteracted? 693. Give the different forms of bathing. What is the simplest mode of bathing? Can this mode be adopted by invalids with safety? -=-=-=-=-=-=-=-=-=-=-=-= 694. When the heat of the system is adequate, the bather may stand or sit in a shallow tub, while he receives the water from a sponge squeezed over the shoulders or against the body. In this form of bathing, the person is more exposed to the cold air, and on this account it is less suitable for very feeble individuals than the first-mentioned method. In the early use of this form of the sponge-bath, the bather should content himself with a single affusion from the sponge; the body should be quickly wiped with a soft towel, and friction applied with a crash towel or a brush. 695. The third kind of bathing is that of the shower-bath, which provides a greater amount of affusion than the former, combined with a greater shock to the nervous system. The concussion of the skin by the fall of water, particularly distinguishes this from the previous modes of bathing. The degree of concussion is modified by the size of the openings through which the water issues, and the height of the reservoir. The shower-bath admits of modification, adapting it to the most delicate as well as the robust. The extent of fall, the size of the apertures, the quantity and temperature of the water, may be regulated at pleasure. _Observation._ In using the shower-bath, it would be judicious to commence with warm or tepid water, for which, by a gradual process, cold water may be substituted. In this way the system may be inured to cold water. After bathing, the skin should be wiped dry and rubbed briskly. 696. The fourth form of bathing is that in which the body, or a portion of it, is immersed in water. The temperature of water in this form of bathing may be modified according to the sensations and purposes of the bather. This form of bathing is designated according to the heat of the water. When the temperature is below 75°, it is termed a cold bath; when from 75° to 85°, a temperate bath; from 85° to 95°, a tepid bath; from 95° to 98°, a warm bath; from 98° to 105°, a hot bath. In using this form of bathing, the skin should be wiped perfectly dry, and briskly rubbed. -=-=-=-=-=-=-=-=-=-=-=-= What is the test by which to estimate, the benefit of all modes of bathing? 694. Give another method of sponge-bathing. 695. What is said of the shower-bath? What caution is given? 696. Give the fourth form of bathing. -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ The length of time a person may remain in a cold bath with benefit varies from two to ten minutes; while a person may remain in a temperate, tepid, or warm bath, from ten to thirty minutes, or until special indications are exhibited. 697. In the vapor-bath, the vapor is not only applied to the exterior of the system, but it is inhaled and brought in contact with every part of the interior of the lungs. The bather is seated upon a chair, and the vapor gradually turned on around him, until the proper temperature (90° to 110°) is attained. The bath may be continued from ten to thirty minutes. After leaving the bath, attention should be given to the skin, as in other forms of bathing. 698. In order to increase and promote reaction of the skin, various measures and processes are used, some of which are practised in, and others after, quitting the bath. Of the former, the rubbing and brushing the skin are the most common and important. The brisk and efficient friction of the skin with a coarse towel and flesh-brush, after quitting the bath, should never be omitted. This short catalogue embraces all the appliances requisite for the purpose. 699. _Bathing promotes health by its immediate and remote physiological effects on the system._ When the body is moistened with a sponge wet with cold water, or when an affusion by the sponge or shower-bath is used, the skin instantly shrinks, and the whole of its tissue contracts. This contraction diminishes the capacity of the cutaneous system of blood-vessels, and a portion of the blood circulating through them is suddenly thrown upon the more internal parts of the body. The nervous system, among others, participates in it, and is stimulated by the afflux, and communicates its stimulus to the whole system. This causes a more energetic action of the heart and blood-vessels, and a consequent rush of blood back to the skin. This is the state termed _reaction_, the first object and purpose of every form of bathing. -=-=-=-=-=-=-=-=-=-=-=-= What degree of temperature of water is termed a cold bath? A temperate? A tepid? A warm? A hot bath? State the length of time that a person should remain in the different baths. 697. What is said of the vapor bath? 698. Mention the different methods for promoting reaction of the skin. -=-=-=-=-=-=-=-=-=-=-=-= 700. This condition of the skin is known by the redness of the surface, the glow, comfort, and warmth which follow the bath. The bather should direct all his care to insure this effect. By it the internal organs are relieved, respiration is lightened, the heart is made to beat calm and free, the mind is clear and strong, the tone of the muscular system is increased, the appetite is sharpened, and the whole system feels invigorated. This is the end and aim of the bather, and to this all his training tends. The error is, to expect the result without the preparation. 701. In order to promote reaction, and to be efficient in preserving health, bathing should be regular, should be commenced by degrees, and increased by a process of training, and should not be permitted to intrude upon hours devoted to some important function, as digestion. It must not precede or follow too closely a meal, or severe mental or muscular exercise, as reaction is less certain and vigorous when important internal organs are employed, than when they are at rest. When the vital powers are greatest, and the system most free from exhaustion, bathing is most beneficial; hence the morning is preferable to the evening, and the middle of the forenoon to the middle of the afternoon, for this healthful and agreeable duty; as the vital action of the system is most energetic in the early part of the day. -=-=-=-=-=-=-=-=-=-=-=-= 699. What is the effect upon the skin when cold water is applied? What is the first object and purpose of every form of bathing? 700. How is this condition of the skin known? Mention the salutary effects that this condition has on the body. 701. How should bathing be performed, in order to be efficient in preserving health? -=-=-=-=-=-=-=-=-=-=-=-= 702. In regard to the frequency of bathing, the face and neck, from their necessary exposure to the atmosphere, and the impurities which the latter contains, should receive at least two washings in twenty-four hours, one of which should be with soap; the feet, from the confined nature of the coverings which are worn over them, require at least one; the armpits, from the detention, as well as from the peculiar properties of the secretions, at least one; and the hands and arms, as many as seem proper. The whole person should be bathed at least every second day, but the most perfect health of every part of the body would be maintained, if the excretions from the skin were removed daily. 703. In diseases of the skin and internal organs, bathing is a remedial measure of great power. It should never be neglected or omitted. It is not only pleasant and safe, but is really more effective than any medicine administered internally. This, like other curative means, should be applied by the direction and under the eye of the medical adviser, that it may be adapted to the condition of the patient. 704. "From the first hour of man's existence to his latest breath, in health and in sickness, rich or poor, water is always requisite. Baths were dedicated by the ancients to the divinities of medicine, strength, and wisdom, namely, �sculapius, Hercules, and Minerva, to whom might properly be added the goddess of health, Hygeia. The use of water has been enforced as a religious observance, and water has been adopted as one of the symbols of Christianity." -=-=-=-=-=-=-=-=-=-=-=-= When should bathing be performed? 702. How often should we bathe? 703. What is said of bathing in disease? Who should direct the kind of bath proper in different diseases? 704. Were baths dedicated by the ancients? -=-=-=-=-=-=-=-=-=-=-=-= 705. The AIR is an agent of importance in the functions of the skin. It imparts to this membrane oxygen, and receives from it carbonic acid. It likewise removes from it a large portion of the perspiration and the more fluid portions of the oily secretion. In order that the air may accomplish these ends, it is necessary that it come in contact with the body. This is one of the many reasons why we should wear loose and porous clothing. 706. Again, the air should be pure, and free from redundant moisture. In the warm mornings of July and August, the air is loaded with moisture and impurities, and the perspirable matter is not removed from the system as it is when the air is pure and dry. This is the cause of the general lassitude that is experienced during such mornings. As soon as the fog is dispelled, these unpleasant sensations are removed. To sustain the functions of the skin in a healthy state, the parlor, kitchen, sleeping-room, school-house, and work-shop, should be well ventilated. The blood of the system will be purer, and its color of a brighter scarlet, if the skin is surrounded by fresh and pure air, than when it is foul or moist. 707. The LIGHT permeating the skin, not only exercises a salutary influence upon this membrane, but upon the blood, and, through this fluid, upon the whole system. For this reason, the kitchen and the sitting-room, which are the apartments most used by ladies, should be selected from the most pleasant and well-lighted rooms in the house. On the other hand, dark rooms and damp cellar-kitchens should be avoided, as exercising an injurious influence upon both body and mind. 708. The dark, damp rooms, so much used in cities and large villages, by indigent families and domestics, are fruitful causes of disease, as well as of vice, poverty, and suffering. Common observation shows that solar light also exercises much influence upon the vigor and color of vegetables. Plants that are kept in well-lighted rooms, have darker and more brilliant colors than those that grow in darkened apartments. -=-=-=-=-=-=-=-=-=-=-=-= 705. Give the reasons why pure air should be supplied to the skin. 706. What is the cause of the general lassitude in a damp, warm morning? 707. Show the salutary effects of light on the skin. 708. What is one cause of disease and suffering in large villages? -=-=-=-=-=-=-=-=-=-=-=-= 709. BURNS and SCALDS are terms applied to those conditions of the skin which are produced by the application of an undue amount of heat, which changes the action of its vessels. 710. A small degree of heat will irritate the nerves, and cause an increased action of the blood-vessels. This is attended with severe smarting pain, and will be followed by the deposition of serum under the cuticle, unless applications are made immediately, to prevent vesication, or blistering. To prevent or suppress this state of arterial action, wet some folds of cotton or woollen cloth with cold water, and apply them to the parts scalded; continue to apply cold water, so as to steadily maintain the low temperature of the applications, as long as the _smarting pain_ is experienced. The steady application of cold dressing also tends to prevent an increased action of the blood-vessels, and will suppress it, if it already exist. 711. When blisters are formed, the cuticle is separated from the other tissues of the skin by the effusion of serum. In all cases, if this layer of the skin is not removed, a small opening should be made in the raised cuticle, by which the serum deposited may be removed. Under such circumstances, never remove the cuticle, as it makes the best possible covering for the blood-vessels and nerves of the true skin. The cold water dressing, recommended in the preceding paragraph, may then be applied as long as the smarting sensation continues. After the pain has subsided, the blistered part may be covered by a patch of cotton or linen cloth, upon which an ointment, made of lard and bees-wax, has been spread. -=-=-=-=-=-=-=-=-=-=-=-= 709. To what condition of the skin are the terms burns and scalds applied? 710. What is the effect when only a small degree of heat is applied to the skin? How can vesication be prevented? 711. What should be the treatment when blisters are formed? -=-=-=-=-=-=-=-=-=-=-=-= 712. If the cuticle has been removed, there will be much suffering, because the nerves are unduly stimulated by the air. The cuticle is the sheath or covering of the vessels and nerves of the skin, and when it is removed, a substitute should be applied. This substitute should be soothing, and cover the denuded surface. Linseed-meal or ground slippery-elm bark poultice, fresh cream, or lard and bees-wax, spread upon linen or cotton cloth, would make a good dressing. When dressings are applied, they should not be removed until they become dry and irritating. 713. If there is much suffering, administer to an adult from twenty-five to sixty drops of laudanum, according to the severity of the pain. If the patient is a child, from fifteen drops to a tea-spoonful of paregoric may be administered. When there is much prostration, some hot peppermint tea or other stimulant may be found necessary to bring on reaction. 714. The hands, feet, ears, &c., are subject, in cold latitudes, to be _frozen_, or _frost-bitten_. This may occur when the patient, at the moment, is not aware of it. The part affected at first assumes a dull red color, which gradually gives place to a pale, waxy appearance, and becomes quite insensible. The first thing to be done in such cases, is to reëstablish circulation. This should be effected very gradually. If a large quantity of blood is thrown suddenly into the chilled and debilitated vessels of the frozen part, inflammation may be produced that will destroy the vitality of the limb. -=-=-=-=-=-=-=-=-=-=-=-= 712. That should be the treatment if the cuticle has been removed? How often should the dressing of burns be removed? 713. What may be necessary when there is much suffering? 714. What is the appearance of limbs while freezing? How should the circulation be at first reëstablished? What should be avoided? -=-=-=-=-=-=-=-=-=-=-=-= 715. The circulation and sensibility may be restored by rubbing the frozen limb, with snow, or, when this is not to be obtained, cold water; but snow is always to be preferred. The fire should be avoided; and it would be better for the patient to be kept in a cold room, for a time, where there is no fire, or where the temperature is moderate. 716. When a person is found benumbed with cold, and almost or quite insensible, he should be taken into a cold room, the clothing removed, and friction commenced and continued for some time, with _snow_. When warmth begins to be restored, the individual should be rubbed with dry flannel, and the friction continued until reaction takes place. _Observation._ When the toes and heels have been repeatedly chilled, there may be produced a disease called _chilblains_. This affection is attended with tenderness of the parts, accompanied with a peculiar and troublesome itching. The prevention of this disease is in wearing warm hose and thick shoes of ample size. Bathing the feet morning and evening is also a prevention of this disagreeable affection. When chilblains exist, apply cold water, warm camphorated spirits, or turpentine linament. -=-=-=-=-=-=-=-=-=-=-=-= 715. How may the circulation and sensibility be restored? 716. What treatment should be adopted when a person is benumbed with cold? What treatment should be adopted when warmth begins to be restored? What is said of chilblains? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXXV. APPENDAGES OF THE SKIN. 717. The HAIRS are appendages of the skin, and, like the cuticle, they are a product of secretion. They have no blood-vessels or nerves, and, consequently, no vitality. The hairs take their origin from the cellular membrane, in the form of bulbs. Each hair is enclosed beneath the surface by a vascular secretory follicle, which regulates its form during growth. In texture, it is dense, and homogeneous toward the circumference, and porous and cellular in the centre, like the pith of a plant. Every hair has on its surface pointed barbs, arranged in a spiral manner, and directed toward the root of the hair; so that, if a hair be rolled between the fingers, it moves only in one direction. [Illustration: Fig. 118. The hair follicle (1) is represented as imbedded in the cellular membrane, (2,) which is situated beneath the skin. 3, 3, The membranous sac, which has a narrow neck, opening externally by a contracted orifice, through which the hair (4) passes. Its internal surface is smooth, and not adherent to the hair, but separated from it by a reddish fluid. From the bottom of the sac (5) the pulp of the hair arises, and passes through the skin at 6.] -=-=-=-=-=-=-=-=-=-=-=-= 717-723. _Describe the appendages of the skin._ 717. Why have not hairs vitality? Where do they take their origin? Give their structure. What is represented by fig. 118? -=-=-=-=-=-=-=-=-=-=-=-= 718. The color of the hair varies in different individuals, and is generally supposed to depend on the fluids contained in the pith. There are two causes which act in changing the hair gray. The first is, defective secretion of the coloring fluid. The second is, the canals, which convey the fluid into the hair, become obliterated. In the first instance, the hair will remain; in the second, it dies, and drops out; the cuticle of the scalp grows over the canal, which is soon obliterated, and the head becomes bald. _Observation._ It is related that the hair of Marie Antoinette, Queen of France, and others, from excessive mental agitation, changed from black to gray in a single night. This is not strictly true; the secretion may be arrested, but that already deposited in the pith will require days or weeks to be removed. 719. Upon the upper part of the head, the oil-tubes open into the hair-sacs; consequently, the secretion of the oil-glands is spread over the surface of the hair, and not upon the cuticle. This is the cause of the dry, white, branny scales, called "scurf," or "dandruff," upon the head. This is natural, and cannot be prevented. When scurf exists, the only necessary application to remove it, is the frequent use of the hair-brush, and washing with pure water. _Observation._ The secretion of the oil-glands may become impacted around the hairs as they issue from the skin, and thus prevent their outward movement in growing. The pressure of the matter deposited at their bulbs will then cause itching. The comb and the brush may be used to remove the impacted matter, and relieve the disagreeable sensation. 720. The oil is most abundant near the roots of the hair A free use of the brush spreads it along the hairs, and gives them a smooth, glossy appearance. Soap should rarely be used in washing the head, as it will remove the oil which is essential to the health and appearance of the hair. -=-=-=-=-=-=-=-=-=-=-=-= 718. Upon what does the color of the hair depend? What are the causes of the hair becoming gray? What is the cause of the hair dropping out? What is related of Marie Antoinette? 719. How is "dandruff" on the scalp produced? What is the only necessary application to remove it? Give observation. 720. Where is the oil of the hair most abundant? -=-=-=-=-=-=-=-=-=-=-=-= 721. The uses of the hair vary in different regions of the body. Upon the head, it aids in shielding the brain from injury by blows, and it likewise serves to protect this part of the system from heat and cold, thus maintaining equal temperature of the cerebral organ. About the flections of the joints, as in the axilla, (armpit,) they prevent irritation of the skin from friction; in the passages to the ears and nostrils, they present an obstacle to the ingress of insects and foreign bodies; while in the eyebrows and eyelids, they serve to protect the organ of vision. [Illustration: Fig. 119. A section of the end of the finger and nail. 4, Section of the last bone of the finger. 5, Fat, forming the cushion at the end of the finger. 2, The nail. 1, 1, The cuticle continued under and around the root of the nail, at 3, 3, 3.] 722. The NAILS are hard, elastic, flexible, semi-transparent scales, and present the appearance of a layer of horn. The nail is divided into the _root_, the _body_, and the _free portion_. The root is that part which is covered on both surfaces; the body is that portion which has one surface free; the free portion projects beyond the end of the finger. 723. The nail is formed of several laminæ, or plates, that are fitted the one to the other; the deepest is that which is last formed. The nails, as well as the hoofs of animals and the cuticle, are products of secretion. They receive no blood-vessels or nerves. If the cuticle be removed in severe scalds they will separate with it, as the hoofs of animals are removed by the agency of hot water. The nails increase in length and thickness, by the deposition of albumen upon their under surface, and at their roots, in a manner similar to the growth of the cuticle, of which they constitute a part. -=-=-=-=-=-=-=-=-=-=-=-= How can it be spread along the hairs? Why should soap not be used in washing the hair? 721. Of what use is the hair upon the head? About the flexions of the joints? In the nasal and ear passages? Upon the eyebrows and eyelids? 722. Describe the nails. 723. How are they formed? -=-=-=-=-=-=-=-=-=-=-=-= _Observations._ 1st. The nail upon its under surface is fashioned into thin vertical plates, which are received between the folds of the sensitive skin. In this manner, the two kinds of laminæ reciprocally embrace each other, and the firmness of connection of the nail is maintained. If we look on the surface of the nail, we see an indication of this structure in the alternate red and white lines which are there observed. The former of these correspond with the sensitive laminæ; the latter with the horny plates. The ribbed appearance of the nail is due to the same circumstance. These sensitive laminæ are provided with an unusual number of capillary vessels for the formation of the nail, and hence they give a red tint to the portion under which they lie. 2d. Near the root of the nail there is a part that is not laminated, and it is less abundantly supplied with blood-vessels. This portion consequently looks pale compared with the laminated portion, and from its half-moon shape is technically termed _lunula_. Beyond the lunula, the root of the nail is imbedded in the fold of the sensitive skin, and has the same relation to that structure that any single one of the thin horny plates of its under surface has to its corresponding pair of sensitive laminæ. 724. The nails, from their position, are continually receiving knocks, which produce a momentary disturbance of their cell formation, followed by a white spot. The care of the nails should be strictly limited to the knife or scissors, to their free border, and an ivory presser, to prevent adhesion of the free margin of the scarf-skin to the surface of the nail. This edge of the cuticle should never be pared, the surface of the nail never scraped, nor the nails cleaned with any instrument whatever, except the nail-brush, aided by water and soap. An observance of these suggestions, will prevent irregularities and disorders of the nails. -=-=-=-=-=-=-=-=-=-=-=-= Give observation 1st. Observation 2d. 724. How should the nails be treated to prevent irregularities and disease? -=-=-=-=-=-=-=-=-=-=-=-= _Observations._ 1st. When we wear a shoe that is too short for the foot, the edge of the nail is brought against the leather. This interrupts the forward growth of the nail, and it spreads out on the sides, and becomes unusually thick. It then presses upon the soft parts, and is said to "grow into the flesh." The prevention is, to wear shoes of ample size. 2d. Instances are by no means unfrequent in which the power of production of the nail at the root becomes entirely destroyed, and it then grows in thickness only. When this affection occurs, it is often remarkable what a mass the nail presents. Instances are on record, where the nail is regularly shed; and, whenever the old nail falls off, a new one is found beneath it, perfectly formed. Sometimes the growth in length is not entirely checked, although growth in thickness is induced; the nail then presents a peculiar appearance. -=-=-=-=-=-=-=-=-=-=-=-= What causes the edge of the nail "to grow into the flesh" of the toe? How prevented? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXXVI. THE NERVOUS SYSTEM. 725. In the preceding chapters, we have seen how various and complex are many of the motions necessary to maintain the life of an animal whose organization is superior to all others. We have noted the wonderful mechanism of the muscular system, in producing the varied movements of the body, the different processes by which the food is converted into chyle and mixed with the blood, and the circulation of this fluid to every organ and tissue of the system, that each may select from it the very principles which it requires for its growth. 726. Lymphatic absorption commences as soon as nutrition is completed, and conveys the useless, worn-out particles of different tissues back into the circulating fluid; while the respiratory organs and secretory glands perform the work of preparing the waste products to be eliminated from the body. Each of these processes effects a single object, and is performed in a regular manner. 727. "They must succeed each other in proper order in propelling every particle to its proper destination, or life would be sacrificed almost at the moment of its commencement. There is, therefore, a mutual dependence of all portions of the machinery of organic life upon each other, and a necessity for some medium of communication from one organ to another, by which they may convey mutual information of their several conditions, if we may be permitted to employ a figurative expression. Were there no such medium, how would the stomach notify the heart that additional exertion on its part is required, because the stomach is busy in digesting food? -=-=-=-=-=-=-=-=-=-=-=-= 725. What has been noted in the preceding chapters? 726. Show the manner in which the several processes are performed. 727. How must they succeed each other? -=-=-=-=-=-=-=-=-=-=-=-= 728. "When we are exerting the muscular system for a long time in some laborious employment, how else are our members to inform the stomach that they are too much occupied with their duties to spare the blood necessary in digestion; that it is requisite that the appetite should decline; and that digestion should cease for the time, even if the stomach should be oppressed with its contents? When we are thinking, how else are the blood-vessels to be told that an unusual supply of their contents is wanting in the head? or when the whole frame is weary with exertion, how, without some regular line of intelligence between all the organs, is the brain to be instructed that circumstances require that it should go to sleep? To supply the necessary medium of communication, Providence has furnished all the animals that possess distinct organs, with a peculiar apparatus called the _Nervous System_." ANATOMY OF THE NERVOUS SYSTEM. 729. The NERVOUS SYSTEM consists of the _Cer´e-bro-spi´nal Cen´tre_, and of numerous rounded and flattened white cords, called _nerves_, which are connected at one extremity with the cerebro-spinal centre, and at the other, distributed to all the textures of the body. The sympathetic nerve is an exception to this description; for, instead of one, it has many small centres, which are called _gan´gli-a_, and which communicate very freely with the cerebro-spinal centre, and with its nerves. -=-=-=-=-=-=-=-=-=-=-=-= 728. What is the medium of communication from one organ to another? 729-754. _Give the anatomy of the brain and cranial nerves._ 729. Of what does the nervous system consist? What constitutes an exception to this? -=-=-=-=-=-=-=-=-=-=-=-= 730. The CEREBRO-SPINAL CENTRE consists of two portions: The _brain_, and the _spinal cord_. For convenience of description, the nervous system may be divided into the _Brain_, _Cranial Nerves_, _Spinal Cord_, _Spinal Nerves_, and the _Sympathetic Nerve_. 731. The term BRAIN designates those parts of the nervous system, exclusive of the nerves themselves, which are contained within the cranium, or skull-bones; they are the _Cer´e-brum_, _Cer-e-bel´lum_, and _Me-dul´la Ob-lon-ga´ta_. These are invested and protected by the membranes of the brain, which are called the _Du´ra Ma´ter_, _A-rach´noid_, and _Pi´a Ma´ter_. [Illustration: Fig. 120. 1, 1, The scalp turned down. 2, 2, 2, The cut edge of the bones of the skull. 3, The external strong membrane of the brain (dura mater,) suspended by a hook. 4, The left hemisphere of the brain, showing its convolutions.] -=-=-=-=-=-=-=-=-=-=-=-= 730. Of what does the cerebro-spinal centre consist? How is the nervous system divided? 731. What does the term brain designate? Name them. How are they protected? Describe fig. 120. -=-=-=-=-=-=-=-=-=-=-=-= 732. The CEREBRUM IS divided into two hemispheres, by a cleft, or fissure. Into this cleft dips a portion of the dura mater, called the _falx cer´e-bri_, from its resembling a sickle. The apparent design of this membrane is to relieve the one side from the pressure of the other, when the head is reclining to either side. Upon the superior surface of the cerebrum are seen undulating windings, called _con-vo-lu´tions_. Upon its inferior, or lower surface, each hemisphere admits of a division into three lobes--the anterior, middle, and posterior. (Fig. 122, 123) [Illustration: Fig. 121 A section of the skull-bones and cerebrum. 1, 1, The skull. 2, 2, the dura mater 3, 3, The cineritious portion of the cerebrum. 4, 4, The medullary portion. The dark points indicate the position of divided blood-vessels. 5, 5, The lateral ventricles.] -=-=-=-=-=-=-=-=-=-=-=-= 732. How is the cerebrum divided? What is the use of the falx cerebri? What is seen upon the superior surface of the brain? Its inferior? -=-=-=-=-=-=-=-=-=-=-=-= 733. When the upper part of the hemispheres is removed horizontally with a sharp knife, a centre of white substance is brought to view. This is surrounded by a border of gray, which follows the depressions of the convolutions, and presents a zigzag outline. The divided surface will be seen studded with numerous small red points, which are produced by the escape of blood from the division of the minute arteries and veins. The gray border is called the cortical, or _cineritious_ portion, while the white central portion is called the _medullary_. The two hemispheres are connected by a dense layer of transverse fibres, called _cor´pus cal-lo´sum_. 734. In the interior of the brain there are several cavities, two of which are of considerable size, and are called the lateral ventricles. They extend from the anterior to the posterior part of the brain, and wind their way into other parts of the cerebral organ. _Observation._ In the disease called "dropsy of the brain," (hydrocephalus internus,) the serum, or water, is usually deposited in these ventricles. This is effused from the many small blood-vessels of the membrane in these cavities. 735. The brain is of a pulpy character, quite soft in infancy and childhood; but it gradually becomes more and more consistent, and in middle age it assumes the form of determinate structure and arrangement. It is more abundantly supplied with blood than any organ of the system. No lymphatics have been detected, but it is to be presumed that they exist in this organ. 736. The CEREBELLUM is about seven times smaller than the cerebrum. Like that organ, it is composed of white and gray matter, but the gray constitutes the larger portion. Its surface is formed of parallel plates separated by fissures. The white matter is so arranged, that when cut vertically, the appearance of the trunk and branches of a tree (_ar´bor vi´tæ_) is presented. It is situated under the posterior lobe of the cerebrum, from which it is separated by a process of the dura mater, called the _ten-to´ri-um_. -=-=-=-=-=-=-=-=-=-=-=-= 733. Describe the appearance of the brain when a horizontal section has been made. What is the gray border often called? What connects the hemispheres? 734. Describe the ventricles of the brain. In the disease called "dropsy of the brain," where is the water deposited? 735. What is the character of the brain in childhood? In adults? 736. How does the cerebellum compare in size with the cerebrum? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 122. The under surface, or base, of the brain and origin of the cranial nerves. 1, 1, The anterior lobes of the cerebrum. 2, 2, The middle lobes. 3, 3, The posterior lobes, almost concealed by the cerebellum. 4, 4, The cerebellum. 7, 7, The longitudinal fissure that divides the brain into two hemispheres. 8, The first pair of nerves. 9, 9, The second pair of nerves. 10, The decussation, or crossing, of its fibres. 13, 13, The third pair of nerves. 14, The pons varolii. 15, 15, The fourth pair of nerves. 16, 16, The fifth pair of nerves. 17, The sixth pair of nerves. 18, 18, The seventh and eighth pair of nerves. 19, The medulla oblongata, with the crossing of some of its fibres exhibited. 20, The ninth pair of nerves. 21, The tenth pair of nerves, 22, The eleventh pair of nerves. 23, The twelfth pair of nerves.] -=-=-=-=-=-=-=-=-=-=-=-= Describe this portion of the brain. Explain fig. 122. -=-=-=-=-=-=-=-=-=-=-=-= 737. The MEDULLA OBLONGATA, or that portion of the spinal cord which is within the skull, consists of three pairs of bodies, (_cor´pus py-ram-i-da´le_, _res-ti-for´me_, and _ol-i-va´re_,) united in a single bulb. [Illustration: Fig. 123. The base of the skull and the openings through which the cranial nerves pass. 1, 1, The first pair of nerves. 2, 2, The cribriform plate of the ethmoid bone through which this nerve passes. 3, 3, The second pair of nerves. 4, 4, The optic foramen in the sphenoid bone; through which passes the second pair of nerves. 5, 5, The sphenoidal fissure. 6, 6, The third pair of nerves. 7, 7, The fifth pair of nerves. 8, 8, The ophthalmic branch of the fifth nerve. The third, the ophthalmic branch of the fifth and the sixth nerve pass from the brain through the sphenoidal fissure to the eye. 9, 9, The superior maxillary branch of the fifth nerve. 10, 10, The foramen rotundum, (round opening,) through which the nerve 9, 9, passes to the upper jaw. 11, 11, The inferior maxillary branch of the fifth pair. 12, 12, The foramen ovale, (oval opening,) through which the nerve 11, 11, passes to the lower jaw. 13, 13, The sixth pair of nerves. 14, 14, The seventh and eighth pair of nerves. 15, 15, The opening in the temporal bone, through which the seventh and eighth nerves pass to the face and ear. 16, 16, The ninth pair of nerves. 17, The tenth pair of nerves. 18, 18, The eleventh pair of nerves. 19, 19, The foramen lacerum (rough opening.) The ninth, tenth, and eleventh nerves pass from the brain through this opening. 20, The spinal cord. 21, The foramen spinalis, through which the spinal cord passes. 22, 22, The position of the anterior lobe of the brain. 23, 23, The middle lobe. 24, 24, The posterior lobe. 25, 25, A section of the skull-bones.] -=-=-=-=-=-=-=-=-=-=-=-= 737. Describe the medulla oblongata. Explain fig. 123. -=-=-=-=-=-=-=-=-=-=-=-= 738. The DURA MATER is a firm, fibrous membrane, which is exposed on the removal of a section of the skull-bones. This lines the interior of the skull and spinal column, and likewise sends processes inward, for the support and protection of the different parts of the brain. It also sends processes externally, which form the sheaths for the nerves, as they quit the skull and spinal column. The dura mater is supplied with arteries and nerves. [Illustration: Fig. 124. A vertical section of the cerebrum, cerebellum, and medulla oblongata, showing the relation of the cranial nerves at their origin. 1, The cerebrum. 2, The cerebellum, with its arbor vitæ represented. 3, The medulla oblongata. 4, The spinal cord. 5, The corpus callosum. 6, The first pair of nerves. 7, The second pair. 8, The eye. 9, The third pair of nerves. 10, The fourth pair. 11, The fifth pair. 12, The sixth pair. 13, The seventh pair. 14, The eighth pair. 15, The ninth pair. 16, The tenth pair. 10, The eleventh pair. 18, The twelfth pair. 20, Spinal nerves. 21, The tentorium.] -=-=-=-=-=-=-=-=-=-=-=-= 738. Describe the dura mater. What is its use? Explain fig. 124. -=-=-=-=-=-=-=-=-=-=-=-= 739. The ARACHNOID, so called from its extreme tenuity, is the serous membrane of the brain and spinal cord, and is, like other serous membranes, a closed sac. It envelops these organs, and is reflected upon the inner surface of the dura mater, giving to that membrane its serous investment. 740. The PIA MATER is a vascular membrane, composed of innumerable vessels, held together by cellular membrane. It invests the whole surface of the brain, and dips into its convolutions. The pia mater is the nutrient membrane of the brain, and receives its blood from the carotid and vertebral arteries. Its nerves are minute branches of the sympathetic, which accompany the branches of the arteries. 741. The CRANIAL NERVES, that connect with the brain, are arranged in twelve pairs. They are called: 1st. The _Ol-fact´o-ry_. 2d. The _Op´tic_. 3d. The _Mo-to´res Oc-u-lo´rum_. 4th. The _Pa-thet´i-cus_. 5th. The _Tri-fa´cial_. 6th. The _Ab-du-cen´tes_. 7th. The _Por´ti-o Du´ra_. 8th. The _Por´ti-o Mol´lis_. 9th. The _Glos´so-pha-ryn´gi-al_. 10th. The _Pneu-mo-gas´tric_. 11th. The _Spi´nal Ac´ces-so-ry_. 12th. The _Hy´po-glos´sal_. 742. The OLFACTORY NERVE (first pair) passes from the cavity of the skull through many small openings in a plate of the _eth´moid_ bone. (This plate is called _crib´ri-form_, from its resemblance to a sieve.) This nerve ramifies upon the membrane that lines the nasal passages. It is the softest nerve of the body. (Fig. 136.) 743. The OPTIC NERVE (second pair) passes from the interior of the cranium, through an opening in the base of the skull, (_fo-ra´men op´ti-cum_,) to the cavity for the eye. It pierces the coats of the eye, and expands in the retina. 744. The MOTORES OCULORUM (third pair) pass from the brain, through an opening of the _sphe´noid_ bone, (_sphe-noid´al fis´sure_,) to the muscles of the eye. -=-=-=-=-=-=-=-=-=-=-=-= 739. Describe the arachnoid membrane. 740. What is said respecting the pia mater? 741. How many pairs of cranial nerves? Name them. 742. Describe the olfactory nerve. 743. The optic nerve. 744. Describe the motores oculorum. -=-=-=-=-=-=-=-=-=-=-=-= 745. The PATHETICUS (fourth pair) passes from the brain, through the sphenoidal fissure, to the superior oblique muscle of the eye. [Illustration: Fig. 125. The distribution of the third, fourth, and sixth pairs of nerves, to the muscles of the eye. 1, The ball of the eye and rectus externus muscle. 2, The upper jaw. 3, The third pair, distributed to all the muscles of the eye, except the superior oblique, and external rectus. 4, The fourth pair passes to the superior oblique muscle. 6, The sixth pair, is distributed to the external rectus muscle.] 746. The TRIFACIAL NERVE (fifth pair) is analogous to the spinal nerves in its origin by two roots, from the anterior and posterior columns of the spinal cord. It has a ganglion, like the spinal nerves upon its posterior root. For these reasons, it ranges with the spinal nerves, and is considered the cranial spinal nerve. This nerve divides into three branches:--The _oph-thal´mic_, superior _max´il-la-ry_, and inferior _max´il-la-ry_. -=-=-=-=-=-=-=-=-=-=-=-= 745. The patheticus. What does fig. 125 represent? 746. What is the trifacial nerve sometimes called? Why is it classed with the cranial spinal nerves? Give the names of its branches. -=-=-=-=-=-=-=-=-=-=-=-= 747. The ophthalmic nerve passes from the cranial cavity through the sphenoidal fissure. It sends branches to the forehead, eye, and nose. The superior maxillary nerve passes through an opening in the base of the skull, (_foramen ro-tund´dum_,) and sends branches to the eye, the teeth of the upper jaw, and the muscles of the face. The inferior maxillary nerve escapes from the cranial cavity through an opening called _foramen o-va´le_. It sends branches to the muscles of the lower jaw, the ear, the tongue, and the teeth of the lower jaw. [Illustration: Fig. 126. The distribution of the fifth pair of nerves. 1, The orbit for the eye. 2, The upper jaw. 3, The tongue. 4, The lower jaw. 5, The fifth pair of nerves. 6, The first branch of this nerve, that passes to the eye. 9, 10, 11, 12, 13, 14, Divisions of this branch. 7, The second branch of the fifth pair of nerves is distributed to the teeth of the upper jaw. 15, 16, 17, 18, 19, 20, Divisions of this branch. 8, The third branch of the fifth pair, that passes to the tongue and teeth of the lower jaw. 23. The division of this branch that passes to the tongue, called the _gust´a-to-ry_. 24. The division that is distributed to the teeth of the lower jaw.] -=-=-=-=-=-=-=-=-=-=-=-= 747. Where do the filaments of the ophthalmic branch ramify? The superior maxillary? The inferior maxillary? Explain fig. 126. -=-=-=-=-=-=-=-=-=-=-=-= 748. The ABDUCENTES (sixth pair) passes through the opening by which the carotid artery enters the cranial cavity. It is the smallest of the cerebral nerves, and is appropriated to the external straight muscle of the eye. 749. The PORTIO MOLLIS (seventh pair) enters the hard portion of the _tem´po-ral_ bone at the internal auditory opening, and is distributed upon the internal ear. (Fig. 147, 148.) [Illustration: Fig. 127. A representation of the distribution of the eighth pair of nerves with some branches of the fifth. 1, 2, 3, 5, 7, 9, Are branches of the eighth pair. They are distributed over the face in a radiated manner, which constitutes the pes anserinus, (foot of a goose.) The nerves 4, 6, 8, are branches of the fifth pair. 10, 11, 12, 13, 14, 15, 16, Are branches of nerves from the upper part of the spinal cord, (cervical.)] 750. The FACIAL NERVE (eighth pair) passes from the skull through an opening situated below the ear, (_mas´toid foramen_.) It is distributed over the face, supplying the muscles with nervous filaments. -=-=-=-=-=-=-=-=-=-=-=-= 748. What is said of the abducentes, or sixth pair of nerves? 749. Of the portio mollis? Explain fig. 127. 750. Of the facial nerve? -=-=-=-=-=-=-=-=-=-=-=-= 751. The GLOSSO-PHARYNGEAL NERVE (ninth pair) passes from the brain, through an opening with the jugular vein, (_foramen lac´e-rum_.) It is distributed to the mucous membrane of the tongue and throat, and also to the mucous glands of the mouth. 752. the PNEUMOGASTRIC NERVE (tenth pair) escapes from the brain through the foramen lacerum. It sends branches to the larynx, pharynx, oesophagus, lungs, spleen, pancreas, liver, stomach, and intestines. (Fig. 132.) 753. The SPINAL ACCESSORY NERVE (eleventh pair) has its origin in the respiratory tract of the spinal cord. It connects with the ninth and tenth pairs of nerves, and is distributed to the muscles about the neck. 754. The HYPO-GLOSSAL NERVE (twelfth pair) passes from the brain, through a small opening, (_con´dy-loid foramen_.) It ramifies upon the muscles of the tongue, and is its motor nerve. _Observation._ The cranial nerves, with the exception of the olfactory, optic, and auditory, connect with each other by means of filaments. They also send connecting nervous filaments to the upper spinal nerves, (cervical,) and the sympathetic nerve. -=-=-=-=-=-=-=-=-=-=-=-= 751. Describe the glosso-pharyngeal nerve. 752. The pneumogastric nerve. 753. The spinal accessory nerve. 754. The hypo-glossal nerve. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXXVII. ANATOMY OF THE NERVOUS SYSTEM, CONTINUED. 755. The spinal column contains the spinal cord, the roots of the spinal nerves, and the membranes of the cord. 756. The SPINAL CORD extends from the medulla oblongata to the second lumbar vertebra, where it terminates in a rounded point. It presents a difference of diameter in different parts of its extent, and exhibits three enlargements. The uppermost of these is the medulla oblongata. There is no distinct demarkation between this enlargement and the spinal cord. The next corresponds with the origin of the nerves distributed to the upper extremities; the third enlargement is situated near the termination of the cord, and corresponds with the attachment of the nerves which are intended for the supply of the lower extremities. 757. An anterior and posterior fissure divides the spinal cord into two lateral cords. These are united by a thin layer of white substance. The lateral cords are each divided by furrows into three distinct sets of fibres, or columns; namely the _anterior_, _lateral_, and _posterior_ columns. The anterior are the motor columns; the posterior are the columns of sensation; the lateral columns are divided in their function between motion and sensation. They contain the fasciculus described, by Sir Charles Bell, as the respiratory tract. [Illustration: Fig. 128. A section of the brain and spinal column. 1, The cerebrum. 2, The cerebellum. 3, The medulla oblongata. 4, 4, The spinal cord in its canal.] [Illustration: Fig. 129. Anterior view of the brain and spinal cord. 1, 1, The two hemispheres of the cerebrum. 3, 3, The cerebellum. 4, The olfactory nerve. 5, The optic nerve. 7, The third pair of nerves. 8, The pons varolii. 9, The fourth pair of nerves. 10, The lower portion of the medulla oblongata. 11, 11, The spinal cord. 12, 12, Spinal nerves. 13, 13, The brachial plexus. 14, 14, The lumbar and sacral plexus.] -=-=-=-=-=-=-=-=-=-=-=-= 755-767. _Give the anatomy of the spinal cord, spinal nerves, and the sympathetic nerve._ 755. What does the spinal column contain? 756. Give the extent of the spinal cord. How many enlargements has this cord? What is said of each enlargement? 757. Into how many parts is the spinal cord divided? Give the function of these columns. -=-=-=-=-=-=-=-=-=-=-=-= 758. The SPINAL NERVES, that connect with the spinal cord, are arranged in thirty-one pairs, each arising by two roots; an anterior, or _motor_ root, and a posterior, or _sensitive_ root. Each nerve, when minutely examined, is found to consist of an aggregate of very delicate filaments, enclosed in a common cellular envelope. -=-=-=-=-=-=-=-=-=-=-=-= 758. How many pairs of nerves issue from the spinal cord? Explain fig. 128. Fig. 129. -=-=-=-=-=-=-=-=-=-=-=-= 759. The anterior roots arise from a narrow white line upon the anterior columns of the spinal cord. The posterior roots arise from a narrow gray band formed by the internal gray substance of the cord. They are larger, and the filaments of origin more numerous than those of the anterior roots. A ganglion is found upon each of the posterior roots in the openings between the bones of the spinal column through which the nerve passes. [Illustration: Fig. 130. A section of the spinal cord, surrounded by its sheath. B, A spinal nerve, formed by the union of the motor root (C) and the sensitive root (D.) At D, the ganglion upon this root is seen.] 760. After the formation of the ganglion, the two roots unite, and constitute a spinal nerve, which passes through the opening between the vertebræ on the sides of the spinal column. The nerves divide and subdivide, until their minute filaments ramify on the tissues of the different organs. -=-=-=-=-=-=-=-=-=-=-=-= 759. Give the origin of the anterior roots. Of the posterior roots. In what respect do the posterior roots differ from the anterior? 760. When do the two roots unite, and where do they pass? -=-=-=-=-=-=-=-=-=-=-=-= 761. The _spinal nerves_ are divided into-- Cervical, 8 pairs, Dorsal, 12 " Lumbar, 5 " Sacral, 6 " 762. The four lower cervical and upper dorsal pass into each other and then separate to reunite. This is called the _brach´i-al plex´us_. From this plexus six nerves proceed, which ramify upon the muscles and skin of the upper extremities. 763. The last dorsal and the five lumbar nerves form a plexus called the lumbar, similar to that of the cervical. Six nerves pass from this plexus, which ramify upon the muscles and skin of the lower extremities. 764. The last lumbar and the four upper sacral unite to form the sacral plexus. From this plexus five nerves proceed, that are distributed to the muscles and skin of the hip and lower extremities. 765. The SYMPATHETIC NERVE[19] consists of a series of _Gan´gli-a_, or knots, extending each side of the spinal column, forming a chain its whole length. It communicates with both the cranial and spinal nerves. With the exception of the neck, there is a ganglion for each intervertebral space. These ganglia are composed of a mixture of cineritious and medullary matter, and are supposed to be productive of peculiar nervous power. [19] The structure of this nerve is very complicated, and different physiologists ascribe to it various functions. The character of its diseases are not well understood. -=-=-=-=-=-=-=-=-=-=-=-= 761. Give the division of the spinal nerves. 762. What nerves constitute the brachial plexus? How many nerves pass from this plexus? 763. How many nerves from the lumbar plexus, and where do they ramify? 764. How is the sacral plexus formed? 765. Of what does the sympathetic nerve consist? How is the sympathetic nerve distributed? What exception? Of what are the ganglia composed? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 131. A beautiful representation of the sympathetic ganglia and their connection with other nerves. It is from the grand engraving of Manec, reduced in size. A, A, A, The semilunar ganglion and solar plexus, situated below the diaphragm and behind the stomach. This ganglion is situated in the region (pit of the stomach) where a blow gives severe suffering. D, D, D, The thoracic ganglia, ten or eleven in number. E, E, The external and internal branches of the thoracic ganglia. G, H, The right and left coronary plexus, situated upon the heart. I, N, Q, The inferior, middle, and superior cervical ganglia. 1, The renal plexus of nerves that surrounds the kidneys. 2, The lumbar ganglion. 3, Their internal branches. 4, Their external branches. 5, The aortic plexus of nerves that lies upon the aorta. The other letters and figures represent nerves that connect important organs and nerves with the sympathetic ganglia.] 766. The GANGLIA may be considered as distinct centres, giving off branches in four directions; namely, the superior, or ascending, to communicate with the ganglion above; the inferior, or descending, to communicate with the ganglion below; the external, to communicate with the spinal nerves; and the internal, to communicate with the sympathetic filaments. It is generally admitted that the nerves that pass from the ganglia are larger than those that entered them; as if they imparted to the nerve some additional power. 767. The branches of distribution accompany the arteries which supply the different organs, and form communications around them, which are called plexuses, and take the name of the artery with which they are associated. Thus we have the mesenteric plexus, hepatic plexus, splenic plexus, &c. All the internal organs of the head, neck, and trunk, are supplied with branches from the sympathetic, and some of them exclusively; for this reason, it is considered a nerve of organic life. -=-=-=-=-=-=-=-=-=-=-=-= What is the design of fig, 131? 766. How may the ganglia be considered? 767. What is said of the branches of the sympathetic nerve? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XXXVIII. PHYSIOLOGY OF THE NERVOUS SYSTEM. 768. The brain is regarded by physiologists and philosophers as the organ of the mind. Most writers consider it as an aggregate of parts, each charged with specific functions, and that these functions are the highest and most important in the animal economy. To the large brain, or cerebral lobes, they ascribe the seat of the faculties of _thinking_, _memory_, and _the will_. In man, this lobe extends so far backward as to cover the whole of the cerebellum. To the cerebellum, or little brain, is ascribed the seat of the _animal_, or _lower propensities_. 769. "The constant relation between mental power and development of brain, explains why capacities and dispositions are so different. In infancy, for example, the intellectual powers are feeble and inactive. This arises partly from the inaptitude of a still imperfect brain; but in proportion as the latter advances toward its mature state, the mental faculties also become vigorous and active." 770. We are able, in most instances, at least, to trace a correspondence between the development of the cerebral lobes and the amount of intelligence possessed by the person. The weight of the brain in man to that of the whole body varies in different individuals. The heaviest brain on record was that of Cuvier, which weighed 4 pounds and 13½ ounces. -=-=-=-=-=-=-=-=-=-=-=-= 768-772. _Give the physiology of the nervous system._ 768. How is the brain regarded by physiologists and philosophers? What do they ascribe to the cerebrum? To the cerebellum? 769. What does the relation between mental powers and development of brain explain? 770. What is said respecting the correspondence between the development of the brain and the amount of intelligence possessed by the person? What is said of the weight of the brain? -=-=-=-=-=-=-=-=-=-=-=-= 771. The brain likewise holds an important relation to all the other organs of the system. To the muscular system it imparts an influence which induces contraction of the fibres. By this relation they are brought under the control of the will. To the skin, eye, and ear, it imparts an influence that gives sensibility, or the power of feeling, seeing, hearing, &c. 772. Again, the involuntary functions of the different portions of the system are more or less influenced by the brain. If the action of this central organ of the nervous system is destroyed, the functions of the digestive, respiratory, and circulatory apparatuses will be much disturbed or entirely suppressed. 773. The brain is the seat of _sensation_. It receives the impressions made on all parts of the body, through the medium of the sensitive nerves. That the impressions of external objects, made on these nerves, be communicated to the brain, where sensation is perceived, it is necessary that they be not diseased or injured. _Observation._ There is a plain distinction between sensations and impressions; the latter are the changes produced in the extremities of the nerve; the former, the changes produced in the brain and communicated to the mind. 774. What part of the brain receives the impressions or has the most intimate relation with the intellectual faculties is unknown. Some portions, however, are of less importance than others. Large portions of the cortical, or outer part, are frequently removed without affecting the functions of this organ. Pieces of the medullary, or central parts, have been removed by injuries without impairing the intellect or destroying life. This organ, although it takes cognizance of every sensation, is, of itself, but slightly sensible. It may be cut, or parts may be removed without pain, and the individual, at the same times retain his consciousness. -=-=-=-=-=-=-=-=-=-=-=-= 771. What is said of the relation of the brain to all of the organs of the body? 772. Are the involuntary functions of different parts of the system influenced by the brain? 773. Where is sensation perceived? By what agency are the impressions of external objects conveyed to the brain? What is the difference between sensations and impressions? 774. Is it known what part of the brain has the most intimate relation with the intellectual faculties? -=-=-=-=-=-=-=-=-=-=-=-= 775. The brain is the seat of the _will_. It superintends the physical as well as the mental movements, and the medium of communication from this organ to the muscles, or the parts to be moved, is the motor nerves. If the brain is in a quiescent state, the muscles are at rest; if, by an act of the will, the brain sends a portion of nervous influence to a voluntary muscle, it immediately contracts, and those parts to which the muscle is attached move. There is no perceptible interval between the act of the will and the motion of the part. 776. Some physiologists assert, that the medulla oblongata is the point at which excitement to motion commences, and sensation terminates; and also, that it possesses the power of originating motion in itself. _Observation._ The medulla oblongata, unlike the brain, is highly sensitive; if slightly punctured, convulsions follow; if much injured, respiration, or breathing, immediately ceases. 777. It is remarkable that the nerves which arise from the right side of the spinal cord communicate with the left hemisphere of the cerebrum, and _vice versa_; this results from the crossing of the fibres in the medulla oblongata. It follows from this, that if the right side of the brain receives an injury, the parts of the opposite side of the body lose their sensibility and motion. _Observations._ 1st. If the cranial nerves which are connected by a single root are divided, only the sensation of the part to which they are distributed is lost. Thus, if the optic nerve is divided, the sense of vision disappears, but the motions of the eye are performed as readily as before. But, if the spinal nerves are divided, both sensation and motion of the part to which they lead are destroyed. -=-=-=-=-=-=-=-=-=-=-=-= What portions have been removed without impairing the intellect? What is remarkable of the brain? 775. What is the influence of the brain upon the muscles? 776. What do some physiologists assert of the medulla oblongata? 777. What is remarkable of the nerves? Give the 1st observation relative to the cranial nerves. -=-=-=-=-=-=-=-=-=-=-=-= 2d. When the spinal cord is divided or compressed, as in fractures of the spinal column, all parts below the fracture are paralyzed, though the nerves leading to these parts may be uninjured. 3d. Again, one side of the body or one limb may become insensible, and the power to move it, be perfectly retained; or the reverse of this may happen--the power of motion will be lost while sensation remains. In the former instance, the function of the posterior, or sensitive column of the spinal cord on one side is destroyed; in the latter, the anterior, or motor column is affected. 4th. In some cases, both sensation and motion of one side of the body or one limb are destroyed. In such instances, both the anterior and the posterior columns of one side of the spinal cord are diseased. 778. Vigorous and controllable muscular contraction requires a sound and well-developed brain. If this organ is defective in these particulars, the movements will be inefficient, and may be irregular. The central organ of the nervous system must, likewise, be in an active condition, to induce regular, steady, and controllable muscular movements. _Observations._ 1st. Persons who have suffered from apoplexy and other severe diseases of the brain, have an involuntary trembling of the limbs, which results from a weakened state of the nervous system. -=-=-=-=-=-=-=-=-=-=-=-= To the spinal nerves. What is said of the compression of the spinal cord? Give the 3d observation relative to the spinal nerves. The 4th observation. 778. Upon what does vigorous controllable muscular contraction depend? What causes the involuntary trembling of the limbs in persons who have suffered from apoplexy? -=-=-=-=-=-=-=-=-=-=-=-= 2d. The tremor of the hand, that lessens the usefulness or incapacitates the fine artist or skilful mechanic, in the prime of life, from pursuing their vocations, may be, and is often, induced by the influence of intoxicating drink, which debilitates and disorganizes the brain. 3d. The tottering step, trembling hand, and shaking head of the aged invalid, are the results of diminished nervous energy, so that steady muscular contraction, so essential to regular movements, cannot be maintained. 779. No difference can be discovered in the structure of the several kinds of nerves in any part of their course, and the functions they are designed to perform can only be known by ascertaining the place of their origin. The nerves may be functionally divided into five groups. 780. 1st. _Nerves of special sensation._ These are the first, second, eighth, and it may be one of the branches of the fifth pair of cranial nerves. The function of these nerves is particularly described in the chapters upon the senses of smell, vision, hearing, and taste. 781. 2d. _Nerves of general sensation._ These embrace the fifth pair of cranial nerves, and the thirty-one pairs of spinal nerves. In those parts that require sensation for their safety and the performance of their functions, there is an abundant supply of sensitive nervous filaments. The nerves of sensation are mostly distributed upon the skin. Few filaments ramify upon the mucous membranes and muscles. _Observations._ 1st. The painful sensations experienced in the face, and in the teeth or jaws, (tic douloureux and toothache,) are induced by irritation and disease of a portion of the filaments of the fifth pair of cranial nerves. -=-=-=-=-=-=-=-=-=-=-=-= The tremor of the hand among some mechanics in the prime of life? The tottering step of the aged invalid? 779. What is said relative to the structure of the nerves? How may they be divided? 780. Give the nerves of special sense. 781. Those of general sensation. Where are the nerves of sensation distributed? What causes tic douloureux? -=-=-=-=-=-=-=-=-=-=-=-= 2d. The unpleasant sensation sometimes experienced when we hear the grating of a file or saw, is produced by the connection of the nerve that passes across the drum of the ear with the fifth cranial nerve. 3d. When pressure is made on the trunk of a nerve, the sensibility of the part where the nerve ramifies is modified. This is illustrated, when pressure is made upon the large nerve of the lower extremity (sciatic) in sitting upon a hard bench. The foot is then said to be "asleep." 4th. When the trunk of a nerve is diseased or injured, the pain is experienced in the outer extremity of the nerve. A blow upon the elbow, which causes a peculiar sensation in the little finger and one side of the ring finger, affords a familiar illustration. This sensation is produced by injuring the ulnar nerve, which is distributed to the little finger. 782. 3d. _Nerves of motion._ These are the third, sixth, and twelfth pairs of cranial nerves, and the thirty-one pairs of spinal nerves. These nerves are distributed to the fibres of the five hundred muscles of the body. The functions of the muscular are different from those of the sensitive nerves. The former are provided for the purpose of motion, and not of feeling. Hence, muscles may be cut, and the pain will be slight, compared with the cutting of the skin. This may be called muscular pain. Weariness is a sensation recognized by one set of muscular nerves. 783. So uniformly is a separate instrument provided for every additional function, that there is strong reason to regard the muscular nerves, although running in one sheath, as in reality double, and performing distinct functions. Sir Charles Bell, in his work on the Nervous System, endeavors to show, that one set of nervous fibres conveys the mandate from the brain to the muscle, and excites the contraction; and that another set conveys, from the muscle to the brain, a peculiar sense of the state or degree of contraction of the muscle, by which we are enabled to judge of the amount of stimulus necessary to accomplish the end desired. This is obviously an indispensable piece of information to the mind in regulating the movements of the body. -=-=-=-=-=-=-=-=-=-=-=-= How is the peculiar sensation accounted for when we hear the grating of a file or saw? What produces the sensation when the foot is said to be "asleep?" What is the effect when the ulnar nerve is injured by a blow? 782. Give the nerves of motion. What is said of the functions of the muscular nerves? 783. What does Sir Charles Bell endeavor to show? -=-=-=-=-=-=-=-=-=-=-=-= 784. 4th. _Nerves of respiration._ These are the fourth, seventh, ninth, tenth, and eleventh pair of cranial nerves, also the phrenic and the external respiratory nerve. All of these nerves have their origin in a distinct tract or column, called the lateral, in the upper part of the spinal cord. Hence it is sometimes named the respiratory column. These nerves are distributed to one of the muscles of the eye; to the muscles of the face; to the tongue, pharynx, oesophagus, stomach, heart, lungs, diaphragm, and some of the muscles of the neck and chest. 785. It is through the instrumentality of the accessory, phrenic, and external respiratory nerves, (10, 11, 12, 13, fig. 132,) that the muscles employed in respiration are brought into action without the necessity of the interference of the mind. Though to a certain extent they may be under the influence of the will, yet it is only in a secondary degree. No one can long suspend the movements of respiration;[20] for in a short time, instinctive feeling issues its irresistible mandate, which neither requires the aid of erring wisdom, nor brooks the capricious interference of the will. [20] Dr. Elliotson, and some other writers On physiology, have detailed cases of death from voluntary suspension of respiration. But these cases are not conclusive, as examinations were not made, so as to determine positively, that death did not result from disease of the heart, brain, or some other vital organ. [Illustration: Fig. 132. The distribution of the respiratory nerves. _a_, Section of the brain and medulla oblongata. _b_, The lateral columns of the spinal cord. _c_, _c_, The respiratory tract of the spinal cord. _d_, The tongue. _e_, The larynx. _f_, The bronchia. _g_, The oesophagus. _h_, The stomach. _i_, The diaphragm. 1, The pneumogastric nerve. 2, The superior laryngeal nerve. 3, The recurrent laryngeal nerve. (These two ramify on the larynx.) 4, The pulmonary plexus of the tenth nerve. 5, The cardiac plexus of the tenth nerve. These two plexuses supply the heart and lungs with nervous filaments. 7, The origin of the fourth pair of nerves, that passes to the superior oblique muscle of the eye. 8, The origin of the facial nerve, that is spread out on the side of the face and nose. 9, The origin of the glosso-pharyngeal nerve, that passes to the tongue and pharynx. 10, The origin of the spinal accessory nerve. 11, This nerve penetrating the sterno-mastoideus muscle. 12, The origin of the internal respiratory or phrenic nerve, that is seen to ramify on the diaphragm. 13, The origin of the external respiratory nerve, that ramifies on the pectoral and scaleni muscles.] -=-=-=-=-=-=-=-=-=-=-=-= 784. Give the respiratory nerves. What is said in reference to the respiratory nerves? 785. Through the agency of what nerves are the respiratory muscles brought into action? Explain fig. 132. -=-=-=-=-=-=-=-=-=-=-=-= 786. The fourth, seventh, and tenth pairs of nerves, (7, 8, 9, fig. 132,) with the spinal accessory, phrenic, and external respiratory, are not only connected with the function of respiration, but contribute to the expression of the passions and emotions of the mind. 787. The influence of this order of nerves in the expression of the passions, is strikingly depicted in Sir Charles Bell's Treatise on the Nervous System. "In terror," he remarks, "we can readily conceive why a man stands with his eyes intently fixed on the object of his fears--the eyebrows elevated, and the eyeballs largely uncovered; or why, with hesitating and bewildered steps, his eyes are rapidly and wildly in search of something. In this way, we only perceive the intense application of his mind to the objects of his apprehension, and its direct influence on the outward organs." -=-=-=-=-=-=-=-=-=-=-=-= Can respiration be suspended for any considerable length of time? 786. What nerves contribute to the expression of the passions and emotions of the mind? 787, 788. What does Sir Charles Bell say of the influence of this order of nerves in the expression of the passions? -=-=-=-=-=-=-=-=-=-=-=-= 788. "But when we observe him further, there is a spasm in his breast; he cannot breathe freely; the chest remains elevated, and his respiration is short and rapid. There is a gasping and convulsive motion of his lips, a tremor on his hollow cheeks, a gasping and catching of his throat; his heart knocks at his ribs, while yet there is no force in the circulation--the lips and cheeks being ashy pale." 789. "These nerves are the instruments of expression, from the smile upon the infant's cheek, to the last agony of life. It is when the strong man is subdued by this mysterious influence of soul on body, and when the passions may be truly said to tear the heart, that we have the most afflicting picture of human frailty, and the most unequivocal proof that it is the order of functions we have been considering, that is thus affected. In the first struggle of the infant to draw breath, in the man recovering from a state of suffocation, and in the agony of passion, when the breast labors from the influence at the heart, the same system of parts is affected, the same nerves, the same muscles, and the symptoms or character have a strict resemblance." 790. The seventh pair of nerves not only communicates the purposes of the will to the muscles of the face, but at the same time it calls them into action, under the influence of instinct and sympathy. On this subject a late writer remarks, "How expressive is the face of man! How clearly it announces the thoughts and sentiments of the mind! How well depicted are the passions on his countenance! tumultuous rage, abject fear, devoted love, envy, hatred, grief, and every other emotion, in all their shades and diversities, are imprinted there, in characters so clear that he that runs may read! How difficult, nay, how impossible, is it to hide or falsify the expressions which indicate the internal feelings! Thus conscious guilt shrinks from detection, innocence declares its confidence, and hope anticipates with bright expectation." _Observation._ The fifth pair of nerves (fig. 126) is distributed to the parts of the face on which the seventh pair ramifies. The former serves for sensation, the latter for motion. Thus, when the seventh pair of nerves is divided, or its functions destroyed by disease, the side affected loses all power of expression, though sensation remains unaffected. On the contrary, if we divide the fifth pair, sensation is entirely destroyed, while expression remains. -=-=-=-=-=-=-=-=-=-=-=-= 789. Are they also the instruments of expression, either of joy or grief? 790. What is said in reference to the seventh pair of nerves? Where is the fifth pair of nerves distributed? -=-=-=-=-=-=-=-=-=-=-=-= 791. 5th. _The sympathetic nerve._ This nerve confers vitality on all the important portions of the system. It exerts a controlling influence over the involuntary functions of digestion, absorption, secretion, circulation, and nutrition. Every portion of the body is, to a certain extent, under its influence, as filaments from this system of nerves accompany the blood-vessels throughout their course. 792. An important use of the sympathetic nerve is to form a communication of one part of the system with another, so that one organ can take cognizance of the condition of every other, and act accordingly. If, for example, disease seizes the brain, the stomach, by its sympathetic connection, knows it; and as nourishment would add to the disease, it refuses to receive food, and perhaps throws off what has already been taken. Loss of appetite in sickness is thus a kind provision of nature, to prevent our taking food when it would be injurious; and following this intimation, we, as a general rule, should abstain from food until the appetite returns. [Illustration: Fig. 133. A back view of the brain and spinal cord. 1, The cerebrum. 2, The cerebellum. 3, The spinal cord. 4, Nerves of the face. 5, The brachial plexus of nerves. 6, 7, 8, 9, Nerves of the arm. 10, Nerves that pass under the ribs, 11, The lumbar plexus of nerves. 12, The sacral plexus of nerves 13, 14, 15, 16, Nerves of the lower limbs.] -=-=-=-=-=-=-=-=-=-=-=-= What is the function of this nerve? What is the effect if the seventh pair is divided, or its function destroyed by disease? 791. What is said of the sympathetic nerve? 792. What is the use of the sympathetic system? Explain fig. 133. -=-=-=-=-=-=-=-=-=-=-=-= _Note._ Let the anatomy and physiology of the nervous system be reviewed from figs. 131, 132, 133, or from anatomical outline plate. No. 8. CHAPTER XXXIX. HYGIENE OF THE NERVOUS SYSTEM. 793. As the different organs of the system are dependent on the brain and spinal cord for efficient functional action, and as the mind and brain are closely associated during life, the former acting in strict obedience to the laws which regulate the latter, it becomes an object of primary importance in education, to discover what these laws are, that we may escape the numerous evils consequent on their violation. 794. _For healthy and efficient action, the brain should be primarily sound_; as this organ is subject to the same general laws as other parts of the body. If the brain of the child is free from defects at birth, and acquires no improper impressions in infancy, it will not easily become diseased in after life. But, if the brain has inherited defects, or has acquired a proneness to disease by mismanagement in early life, it will more easily yield to influences that cause diseased action. The hereditary tendency to disease is one of the most powerful causes that produce nervous and mental affections. Consequently, children have a strong tendency to the diseases from which the parents suffered. 795. When both parents have similar defects, or have descended from tainted families, the children are usually more deeply impressed with their imperfections than when only one possesses the defect. This is the reason of the frequency of nervous disease and imbecility among the opulent, as intermarriages among near relations are more frequent with this class than among the poor. -=-=-=-=-=-=-=-=-=-=-=-= 793-850. _Give the hygiene of the nervous system._ 793. Why is it important to know the laws which regulate the action of the brain? 794. What is necessary that the action of the brain be healthy and efficient? What follows if the brain of the child has inherited defects? 795. What is the effect when both parents possess similar defects? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Among some of the reigning families of Europe, particularly the Spanish, the folly of intermarriage among themselves is strongly illustrated. The high and noble talents that characterized their progenitors are not seen, but there is now exhibited, among their descendants, imbecility and the most revolting forms of nervous disease. 796. "Unhappily, it is not merely as a cause of disease, that hereditary predisposition is to be dreaded. The obstacles which it throws in the way of permanent recovery are even more formidable, and can never be entirely removed. Safety is to be found only in avoiding the perpetuation of the mischief." 797. "Therefore, if two persons, each naturally of excitable and delicate nervous temperament, choose to unite for life, they have themselves to blame for the concentrated influence of similar tendencies in destroying the health of their offspring, and subjecting them to all the miseries of nervous disease, madness, or melancholy." The command of God not to marry within certain degrees of consanguinity, is in accordance with the organic laws of the brain, and the wisdom of the prohibition is confirmed by observation. _Observation._ The inhabitants, females particularly, of the sea-girt islands of America, are more affected with nervous diseases, than those who reside upon the mainland. The prevalence of these affections is ascribed to the frequent intermarriage of persons closely related by blood. -=-=-=-=-=-=-=-=-=-=-=-= What is one cause of nervous disease among the higher classes? What is true of some of the reigning families of Europe? 796. Why is hereditary predisposition to be dreaded? 797. Is the prohibition of God respecting intermarriage in accordance with the organic laws of the brain? What is said of the inhabitants of the sea-girt islands of America? -=-=-=-=-=-=-=-=-=-=-=-= 798. _The brain requires a due supply of pure blood._ This organ receives an unusually large supply of blood, in comparison with the rest of the body. It is estimated that one tenth of all the blood sent from the heart goes to this organ. If the arterial blood be altogether withdrawn, or a person breathes air that is filled with carbonic gas, the brain ceases its proper action, and sensibility with consciousness becomes extinct. _Illustrations._ 1st. If a person lose a considerable quantity of blood, dizziness and loss of consciousness follow. This results from the brain not receiving a sufficient amount of blood to sustain its functions. 2d. When an individual descends into a well or pit that contains carbonic acid, the blood is not changed or purified in the lungs, and loss of consciousness and death soon follow. 799. The slighter variations in the state of the blood have equally sure, though less palpable effects. If its vitality is impaired by breathing an atmosphere so much vitiated as to be insufficient to produce the proper degree of oxygenation, the blood then affords an imperfect stimulus to the brain. As a necessary consequence, languor and inactivity of the mental and nervous functions ensue, and a tendency to headache, fainting, or hysteria, makes its appearance. _Observations._ 1st. Let a person remain, for a time, in a crowded, ill-ventilated, hall or church, and headache or faintness is generally produced. This is caused by the action of impure blood upon the brain. 2d. If a school-teacher wishes to have his pupils, on the day of examination, appear creditably, he will be careful to have the room well ventilated. Ventilating churches might prevent the inattention and sleepiness that are observed during the afternoon service. -=-=-=-=-=-=-=-=-=-=-=-= 798. Why does the brain require a due supply of pure blood? What is the effect when a person loses a considerable quantity of blood? What causes the loss of consciousness when carbonic acid is breathed? 799. What effects are produced by slight variations in the quality of the blood? From the following observations, give some of the effects of impure blood on the brain. -=-=-=-=-=-=-=-=-=-=-=-= 3d. In many instances, the transmission of imperfectly oxygenated blood to the brain, is an influential cause in the production of nervous disease and delicacy of constitution. The only efficient remedy for these conditions is a supply of pure blood to the brain. 800. _The brain should be called into action._ This organ, like the muscles, should be used, and then allowed to rest, or cease from vigorous thought. When the brain is properly called into action by moderate study, it increases in size and strength; while, on the other hand, if it is not used, the action of this organ is enfeebled, thereby diminishing the function of all parts of the body. 801. The brain, being an organized part, is subject, so far as regards exercise, to the same laws as the other organs of the body. If it is doomed to inactivity, its size diminishes, its health decays, and the mental operations and feelings, as a necessary consequence, become dull, feeble, and slow. If it is duly exercised after regular intervals of repose, the mind acquires readiness and strength. Lastly, if it is overtasked, either in the force or duration of its activity, its functions become impaired, and irritability and disease take the place of health and vigor. 802. The consequences of inadequate exercise will first be explained. We have seen that by disuse the muscles become emaciated, the bones soften, and the blood-vessels are obliterated. The brain is no exception to this general rule. It is impaired by permanent inactivity, and becomes less fit to manifest the mental powers with readiness and energy. Nor will this surprise any reflecting person, who considers that the brain, as a part of the same animal system, is nourished by the same blood and regulated by the same vital laws as the muscles, bones, and arteries. -=-=-=-=-=-=-=-=-=-=-=-= 800. Why should the brain be called into action? 801. What is the effect if the brain is doomed to inactivity? 802. Show the consequences of disuse of the organs mentioned in preceding chapters. Does the same principle apply to the brain? -=-=-=-=-=-=-=-=-=-=-=-= 803. It is the weakening and depressing effect which is induced by the absence of the stimulus necessary for the healthy exercise of the brain, that renders solitary confinement so severe a punishment, even to the most daring minds. Keeping the above principle in view, we shall not be surprised to find that _non-exercise_ of the brain and nervous system, or, in other words, inactivity of intellect and feeling, is a very frequent predisposing cause of every form of nervous disease. 804. For demonstrative evidence of this position, we have only to look at the numerous victims to be found among females of the middle and higher ranks, who have no calls to exertion in gaining the means of subsistence, and no objects of interest on which to exercise their mental faculties, and who, consequently, sink into a state of mental sloth and nervousness, which not only deprives them of much enjoyment, but subjects them to suffering, both of body and mind from the slightest causes. 805. But let the situation of such persons be changed; bring them, for instance, from the listlessness of retirement to the business and bustle of the city; give them a variety of imperative employments, and so place them in society as to supply to their cerebral organs that extent of exercise which gives health and vivacity of action, and in a few months the change produced will be surprising. Health, animation, and energy, will take the place of former insipidity and dulness. 806. An additional illustration, involving an important principle in the production of many distressing forms of disease will be found in the case of a man of mature age, and of active habits, who has devoted his life to the toils of business, and whose hours of leisure have been few and short. Suppose such a person to retire to the country in search of repose, and to have no moral, religious, or philosophical pursuits to occupy his attention and keep up the active exercise of his brain; this organ will lose its health, and the inevitable result will be, weariness of life, despondency, or some other variety of nervous disease. -=-=-=-=-=-=-=-=-=-=-=-= 803. What renders solitary confinement so severe a punishment to the most daring minds? What is a predisposing cause of nervous disease? 804. In what classes do mental and nervous debility prevail? 805. How can this be counteracted? 806. Give another illustration, showing how disease of the brain is induced. -=-=-=-=-=-=-=-=-=-=-=-= 807. One great evil attending the absence of some imperative employment or object of interest, to exercise the mind and brain, is the tendency which it generates to waste the mental energies on every trifling occurrence which presents itself, and to seek relief in the momentary excitement of any sensation, however unworthy. The best remedy for these evils is to create occupation to interest the mind, and give that wholesome exercise to the brain, which its constitution requires. 808. _The evils arising from excessive or ill-timed exercise of the brain, or any of its parts, are numerous._ When we use the eye too long, or in too bright a light, it becomes bloodshot. The increased action of its vessels and nerves gives rise to a sensation of fatigue and pain, requiring us to desist. If we relieve the eye, the irritation gradually subsides and the healthy state returns. But, if we continue to look intently, or resume our employment before the eye has regained its natural state by repose, the irritation at last becomes permanent, and disease, followed by weakness of vision, or even blindness, may ensue. 809. Phenomena precisely analogous occur, when, from intense mental excitement, the brain is kept long in a state of excessive activity. The only difference is, that we can always see what happens in the eye, but rarely what takes place in the brain; occasionally, however, cases of fracture of the skull occur, in which, part of the bone being removed, we can see the quickened circulation in the vessels of the brain, as easily as those of the eye. -=-=-=-=-=-=-=-=-=-=-=-= 807. What is one great evil attending the absence of some imperative employment to exercise the mind and brain? What is the true remedy for these evils? 808. From what other cause do evils arise to the brain? Explain the evil of it by the excessive use of the eye. 809. What is the only difference in the analogy of the phenomena of the eye and brain? Has the analogy been verified? -=-=-=-=-=-=-=-=-=-=-=-= 810. Sir Astley Cooper had a young man brought to him, who had lost a portion of his skull, just above the eyebrow. "On examining the head," says Sir Astley, "I distinctly saw that the pulsation of the brain was regular and slow; but at this time he was agitated by some opposition to his wishes, and directly the blood was sent with increased force to the brain, and the pulsation became frequent and violent." 811. Indeed, in many instances, the increased circulation in the brain, attendant on mental excitement, reveals itself when least expected, and leaves traces after death, which are very perceptible. When tasked beyond its strength, the eye becomes insensible to light, and no longer conveys any impressions to the mind. In like manner, the brain, when much exhausted, becomes incapable of thought, and consciousness is almost lost in a feeling of utter confusion. 812. _At any time of life, excessive and continued mental exertion is hurtful_; but in infancy and early youth, when the structure of the brain is still immature and delicate, permanent mischief is more easily produced by injudicious treatment than at any subsequent period. In this respect, the analogy is as complete between the brain and the other parts of the body, as that exemplified in the injurious effects of premature exercise of the bones and muscles. 813. Scrofulous and rickety children are the most usual sufferers in this way. They are generally remarkable for large heads, great precocity of understanding, and small, delicate bodies. But in such instances, the great size of the brain, and the acuteness of the mind, are the results of morbid growth. Even with the best of management, the child passes the first years of its life constantly on the brink of active disease. -=-=-=-=-=-=-=-=-=-=-=-= 810. Relate the case detailed by Sir Astley Cooper. 811. May the increased functional action of the brain change its structure? 812. At what age particularly is excessive and continued mental exertion hurtful? 813. What is said of scrofulous and rickety children? -=-=-=-=-=-=-=-=-=-=-=-= 814. Instead, however, of trying to repress its mental activity, the fond parents, misled by the early promise of genius too often excite it still further, by unceasing cultivation, and the never-failing stimulus of praise. Finding its progress for a time equal to their warmest wishes, they look forward with ecstasy to the day when its talents will break forth and shed lustre on its name. 815. But in exact proportion as the picture becomes brighter to their fancy, the probability of its being realized becomes less; for the brain, worn out by premature exertion, either becomes diseased, or loses its tone, leaving the mental powers imbecile and depressed for the remainder of life. The expected prodigy is thus easily outstripped in the social race by many whose dull outset promised him an easy victory. 816. Taking for our guide the necessities of the constitution, it will be obvious that the modes of treatment commonly resorted to ought to be reversed. Instead of straining to the utmost the already irritable powers of the precocious child, and leaving his dull competitor to ripen at leisure, a systematic attempt ought to be made, from early infancy, to rouse to action the languid faculties of the latter, while no pains ought to be spared to moderate and give tone to the activity of the former. 817. Instead of this, however, the prematurely intelligent child is sent to school and tasked with lessons at an unusually early age, while the healthy but more backward boy, who requires to be stimulated, is kept at home in idleness, perhaps for two or three years longer, merely on account of his backwardness. A double error is here committed. The consequences to the intelligent boy are, frequently, the permanent loss both of health and of his envied superiority of intellect. -=-=-=-=-=-=-=-=-=-=-=-= 814. How are such children usually managed? 815. What is the cause of their early promise and subsequent disappointment? 816. What mode of treatment should be adopted in educating precocious children? 817. How should the dull or less active child be treated? What is the usual course? -=-=-=-=-=-=-=-=-=-=-=-= 818. In youth, too, much mischief is done by the long daily period of attendance at school, and the continued application of the mind which the ordinary system of education requires. The law of exercise--that long-sustained action exhausts the vital powers of the organ--applies as well to the brain as to the muscles. Hence the necessity of varying the occupations of the young, and allowing frequent intervals of exercise in the open air, instead of "enforcing the continued confinement now so common." _Observation._ It is no unusual occurrence, that on examination day, the best scholars appear indifferently. This may be the result of nervous exhaustion, produced by extra mental effort in preparing for the final examination. It is advisable for such pupils to divert their minds from close study for a few days previous to examination. During this time, the student may indulge in physical recreation, social intercourse, and a moderate amount of reading. 819. "In early and middle life, fever, an unusual degree of cerebral disorder, is a common consequence of the excessive and continued excitement of the brain. This unhappy result is brought on by severe study, unremitted mental exertion, anxiety, and watching. Nervous disease, from excessive mental labor and high mental excitement, sometimes shows itself in another form. -=-=-=-=-=-=-=-=-=-=-=-= What are the consequences of the error? 818. What error prevails in the present system of education? Why should youths be allowed frequent intervals to exercise in the open air? Give observation. 819. What is a frequent consequence of continued and excessive excitement of the brain? -=-=-=-=-=-=-=-=-=-=-=-= 820. "From the want of proper intervals of rest, the vascular excitement of the brain has not time to subside. A restless irritability of temper and disposition comes on, attended with sleeplessness and anxiety, for which no external cause can be assigned. The symptoms gradually become aggravated, the digestive functions give way, nutrition is impaired, and a sense of wretchedness is constantly present, which often leads to attempts at suicide." _Observations._ 1st. Moderation in mental exertion is more necessary in old age than in early or mature years. In youth and manhood, the exhaustion of the brain from over-excitement may be repaired, but no such result follows over-exertion in the decline of life. "What is lost then, is lost forever." At that period, the brain becomes excited, and is soon exhausted when forced to protracted and vigorous thought. Sir Walter Scott and President Harrison afford sad examples of premature death from overtasked brains at an advanced period of their lives. 2d. If the mind is incessantly engaged in the contemplation of the same object, there is danger from over-exertion of the brain at any period of life, but more particularly in old age. The more limited the sphere of mental action, the greater the danger of the brain being over-exercised. Hence the frequency of nervous diseases in poets, mathematicians, and musicians. -=-=-=-=-=-=-=-=-=-=-=-= 820. What often manifests itself from the want of proper intervals of rest? Why is moderation in mental action necessary in old age? What is the effect if the mind is incessantly engaged in the contemplation of the same object? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XL. HYGIENE OF THE NERVOUS SYSTEM, CONTINUED. 821. Having pointed out the evils arising both from inadequate and from excessive mental exertion, it remains to direct the attention to some of the rules which should guide us in the exercise of the brain. 822. _We should not enter upon continued mental exertion, or arouse deep feeling, immediately before or after a full meal._ Such is the connection between the mind and body, that even in a perfectly healthy person, unwelcome news, sudden anxiety, or mental excitement, occurring soon after eating, will impede digestion, and cause the stomach to loathe the masticated food. 823. The worst forms of indigestion and nervous depression are those which arise from excessive mental application, or depressed feeling, conjoined with unrestrained indulgence in the pleasures of the table. In such circumstances, the stomach and brain react upon and disturb each other, till all the horrors of nervous disease make their unwelcome appearance, and render life miserable. Too many literary men and students know this from sad experience. 824. _We should engage in intense study in the early part of the day._ Nature has allotted the darkness of the night for repose, and for restoration by sleep of the exhausted energies of mind and body. In the early part of the evening, if study or composition be ardently engaged in, the increased action of the brain, which always accompanies activity of mind, requires a long time to subside. If the individual possesses a nervous temperament, he will be sleepless for hours after he has retired, or perhaps be tormented by unpleasant dreams. -=-=-=-=-=-=-=-=-=-=-=-= 822. Why should we not arouse deep feeling immediately before or after eating a full meal? 823. How are the worst forms of indigestion and nervous depression produced? What class of men know this from sad experience? 824. What evils arise from studious application at night? -=-=-=-=-=-=-=-=-=-=-=-= 825. It is, therefore, of great advantage to enter upon intense mental application early in the day, and to devote several of the hours which precede bedtime to entertaining conversation, music, and lighter reading. The vascular excitement previously induced in the brain by study, has then time to subside, and sound, refreshing sleep is much more certainly obtained. This rule is of great consequence to those who are obliged to undergo much mental labor. _Observation._ The idea of gathering wisdom by burning the "midnight oil," is more poetical than profitable. The best time to use the brain is during the day. 826. _The close student and the growing child need more sleep than the idler or the adult._ As steep is the natural repose of all organs, it follows that the more the brain and other organs of the system are employed, the more repose they require. The organs of the child, beside sustaining their proper functions, are busy in promoting its growth. This nutritive process is attended with a certain degree of exhaustion. The impaired health of children often results from a disregard of this principle. But, on the other hand, an excess of sleep produces feebleness, by preventing the proper exercise of the mind as well as the body. 827. _The length of time the brain may be advantageously used, is modified by many circumstances._ The power of the brain in different persons to endure action, is various. This is modified by its primary character; by development and age; by habits of action; by the health of the cerebral organ and general system; by the moral feelings and other conditions. -=-=-=-=-=-=-=-=-=-=-=-= 825. Why should we engage in intense study in the early part of the day? 826. What persons require the most sleep? Why? 827. What is said relative to the length of time that the brain can be advantageously used? Give a condition that modifies the amount of mental labor. -=-=-=-=-=-=-=-=-=-=-=-= 828. The primary physical organization of some individuals is such, that they are enabled to endure with impunity an amount of mental labor that would disorder, if not destroy functionally, the cerebral organ of others differently constituted. Napoleon Bonaparte was of this number. There can be no fixed period for mental labor, that may be adopted as a rule for all persons whose systems are maturely developed. Much less is there a proper definite period for study, that is applicable to all children. _Observation._ The practice of retaining pupils of all ages, from five to twenty years, in the school-room the same period of time, for the purpose of study, is not predicated upon any law of physiology. An exercise of three hours, with one or two recesses of ten minutes each, may profit the eldest class; two hours with a recess of ten minutes, the middle class; while one hour, or one hour and a half, with one recess, would be as long a period as the youngest pupils should be retained in the study-room at one session. 829. A person who is accustomed to muscular exertion will endure a longer period of physical toil than one who is not inured to it. So it is with mental labor. If the brain has been habituated to mental action and profound study, it will not be so soon fatigued as when not accustomed to such exertions; consequently, an amount of mental labor may be performed with impunity at one time, that would exhaust and cause serious disease of the cerebral organ at another. _Observation._ Persons that commence a course of study at a late period in life, frequently evince their zeal at the commencement by poring over their books twelve or more hours each day. The progress of such students is soon arrested by physical and mental depression. In such instances, it would be more judicious to commence with only three or four hours' vigorous application each day, and gradually protract the period of study five or more minutes every successive day, until the brain may be called into vigorous action six or eight hours with impunity. -=-=-=-=-=-=-=-=-=-=-=-= 828. Why can there be no fixed period for mental labor? What is said of the practice of retaining pupils of all ages the same period of time in the school-room? 829. Show that the action of the brain is influenced by habit, as well as the muscular system. What suggestion to those persons that commence a course of study at a late period in life? -=-=-=-=-=-=-=-=-=-=-=-= 830. The amount of mental power is greatly influenced by the general health. Such is the intimate connection of the different parts of the system, particularly the digestive apparatus, with the cerebral organs, that except there be vigor of constitution, and freedom from disease, mental efforts will be feeble and of little avail. _Observation._ The prevalent opinion, that individuals who are feeble or diseased may acquire a collegiate education, and thus become useful to themselves and the community, is very generally erroneous. Such persons should enter upon a daily and systematic course of physical training, and their labor should be in the open air, in order that the system may be invigorated and freed from disease. 831. The moral feelings exert a controlling influence over the functions of the muscular, digestive, and respiratory organs. They also exert an influence, perhaps, more powerful upon the nervous system. While fear and anxiety depress, hope and the enlivening emotions, facilitate the functional activity of the brain, and increase its power for mental exertion. By a proper and systematic education of the moral feelings, they are not only a source of happiness, and productive of right conduct, but aid in the culture of the intellect. Consequently, we should cultivate a feeling of hopeful trust in the future, and a firm reliance upon the laws which the Creator has given us for our guidance. -=-=-=-=-=-=-=-=-=-=-=-= 830. Show that the amount of mental power is modified by the general health. What is said of feeble persons acquiring a collegiate education? 831. Do the moral feelings exert a controlling influence over the principal functions of the system? What is the effect of a proper and systematic culture of the moral feelings? -=-=-=-=-=-=-=-=-=-=-=-= 832. _Regularity is very important in exercising the moral and intellectual powers._ Periodicity, or a tendency to resume the same mode of action at stated times, is peculiarly the characteristic of the nervous system. If we repeat any kind of mental effort every day at the same hour, we at last find ourselves entering upon it without premeditation when the time approaches. In like manner, if we arrange our studies in accordance with this law, and take up each in the same order, a natural aptitude is soon produced, which renders application more easy than by resuming the subjects as accident may direct. _Observation._ When engaged in abstruse studies, it may be found advantageous to pursue others that are less difficult. The intense application of the brain, which is requisite in the one instance, is relieved by directing the attention to a study that requires less thought. By this change, there is mental relaxation attended with invigoration of the cerebral organ. Or, it may be explained by assuming, that the brain is composed of an aggregate of distinct organs, each of which is called into action in pursuing different studies. 833. Effective study is impossible if the powers of the brain are depressed. When the cerebral organ has been temporarily debilitated by protracted intellectual efforts, it is ineffectual to attempt any concentrated mental exercise. This condition of the nervous system is indicated by confusion of thought and inability to attain results that usually follow similar efforts. Mental rest in these cases is required. _Observation._ Students frequently fail in solving mathematical problems when the mind is prostrated by continued and excessive effort to obtain a solution. Not unfrequently after a night's rest the problem is quickly solved, and the pupil thinks he "dreamed it out." The true explanation is rest invigorated the exhausted brain, which fitted it for vigorous and successful thought. -=-=-=-=-=-=-=-=-=-=-=-= 832. Why is regularity of great importance in exercising the moral and intellectual powers? What suggestion when pursuing abstruse studies? How explained? 833. When is effective study impossible? How is this condition of the nervous system indicated? -=-=-=-=-=-=-=-=-=-=-=-= 834. _The intellect should not be cultivated to the neglect of the moral and physical powers._ All the faculties require for their development regular exercise, alternated with intervals of rest. This is as necessary to the due development of the moral feelings of a child as in physical training and mental culture. Consequently, those schools are to be preferred in the education of youth, where the physical, intellectual, and moral faculties receive each day a due share of attention and culture. 835. The continuance of healthy and vigorous action in the matured physical, mental, and moral powers, requires frequent and regular action, alternated with rest, as much as in their development. Consequently, those who cultivate one or two of these faculties, to the neglect of the others, exhibit a marked deficiency of acuteness and vigor in those not exercised. This defect reacts on the powers that are vigorous, diminishing the energy and deteriorating all the other faculties of man. _Observations._ 1st. If the principles before mentioned are true, the adult, as well as the child, should spend a part of each day in some proper physical employment; another portion should be appropriated to intellectual pursuits; while another should be sedulously devoted to the cultivation of the moral feelings. 2d. Disease of the corporeal system more frequently occurs when only one set of faculties is used than when all are equally employed. This is particularly true of nervous and mental disease, which follows and is caused by either high intellectual action, or intense moral emotions, without a due amount of physical exercise. -=-=-=-=-=-=-=-=-=-=-=-= How is the "dreaming out" of problems explained? 834. What is said of the culture of the intellect? What schools are preferable in the education of youth? Why? 835. What is the effect of cultivating only one faculty of the mind? Give observation 1st. Observation 2d. -=-=-=-=-=-=-=-=-=-=-=-= 836. _The brain can exercise its full force upon only one object at a time._ If its energies are directed to two or more operations, neither will receive that full power of exertion that it would if only one object had engaged the mind. Although the brain will direct several operations at the same time when only slight mental effort is required, yet when one operation becomes difficult, or demands special attention of the mind, the other will be suspended. This is illustrated in social conversation while walking. Let it become necessary to concentrate the nervous power upon the motor organs, and the conversation declines or ceases. 837. In acquiring an education, or in pursuing any profession or trade, none of those influences that promote the proper functions of the body, and tend to increase physical ease, should be neglected. For, if the brain is occupied with disagreeable sensations, it cannot concentrate its power as effectively in the various employments of man. _Observations._ 1st. The situation, ventilation, light, and warmth of a school-room, together with the arrangement of the benches, do much to influence the concentration or distraction of the operations of the mind. Let there be attached to the school-house a spacious yard planted with trees; let its architecture be attractive; let the windows be arranged with regularity, and not with the elevation of a convict's cell, and the benches, in every respect, be adapted to the different scholars, so that the position of each may be comfortable, and we mistake if there is not a greater improvement, in a given time, in such a school, than where there is an apparent disregard to the pleasure or comfort of the scholars. -=-=-=-=-=-=-=-=-=-=-=-= 836. What is the effect if the brain concentrates its energies on more than one object at a time? How illustrated? 837. What should be regarded in pursuing any employment? Why? What is said in reference to the arrangement of school-rooms? -=-=-=-=-=-=-=-=-=-=-=-= 2d. Mechanics' shops should receive as much attention, relative to their situation, light, warmth, &c., as school-rooms. If these are duly observed, the nervous influence transmitted from the brain to the muscles will be more stimulating, as well as more abundant; consequently, labor will be performed with less exhaustion. 838. _Repetition is necessary to make a durable impression on the mind._ "The necessity of judicious repetition in mental and moral education, is, in fact, too little adverted to, because the principle which renders it efficacious has not been understood. To induce facility of action in the organs of the mind, practice is as essential as it is in the organs of motion. 839. "In physical education we are aware of the advantages of repetition. We know that if practice in dancing, fencing, skating, and riding, is persevered in for a length of time sufficient to give the muscles the requisite promptitude and harmony of action, the power will be ever afterward retained, although little called into use; whereas, if the muscles have not been duly trained, we may reiterate practice at different intervals, without proportionate advancement. The same principle applies equally to the moral and intellectual powers, because these operate by means of material organs. 840. "According to this principle, it follows, that in learning a language or science, six successive months of application will be more effectual in fixing it in the mind and making it a part of its furniture, than double or treble the time, if the lessons are interrupted by long intervals. Hence it is a great error to begin and study, and then break off, to finish at a later period. The fatigue is thus doubled, and the success greatly diminished. -=-=-=-=-=-=-=-=-=-=-=-= Of mechanics' shops? 838. Is repetition necessary to make a durable impression on the mind? Why? 839. How is it with physical education? 840. What follows, according to this principle? -=-=-=-=-=-=-=-=-=-=-=-= 841. "The best way is to begin at the proper age, and to persevere till the end is attained. This accustoms the mind to sound exertion, and not to _fits_ of attention. Hence the evil arising from long vacations; and also the evil of beginning studies before the age at which they can be understood, as in teaching children the abstract rules of grammar, to succeed in which, implies in them a power of thinking, and an amount of general knowledge, which they do not possess." 842. _The skull is susceptible of fractures from slight blows._ This occurs most frequently when the blow is given on the side of the head above and anterior to the ear. Here the bone is very thin, and often quite brittle. For these reasons, no instructor, or any person, should punish a child by striking upon any portion of the head. _Observation._ A few years since, a teacher in one of the Middle States gave a pupil a slight blow upon the head. It fractured the skull and ruptured a blood-vessel of the brain, causing a loss of consciousness, and finally death. 843. _Concussion of the brain may be produced by blows, or by violently shaking a person._ As the brain is of pulpy consistence, the atoms of which it is composed, and the circulation of blood in its minute vessels, may be disturbed by the vibration from a blow on the exterior of the skull-bones. This disturbance of the cerebral organ is attended with unpleasant sensations, dizziness, loss of memory and consciousness. These may be followed by headache and inflammation of the brain. Concussion of the brain, and the results above mentioned, may be produced by the sudden motion attendant on the violent shaking of a scholar. Consequently, a child should never be seized by the arm and shaken violently as a method of chastisement. -=-=-=-=-=-=-=-=-=-=-=-= 841. What is the best way of learning the sciences? 842. Why should not a child be struck upon any portion of the head? What observation in this connection? 843. How may concussion of the brain be produced? What is the effect of each upon the brain of the child? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ Most persons have experienced a disagreeable sensation and dizziness, caused by falling from a slight elevation, or by jumping from a carriage. This is the result of a moderate concussion of the brain. 844. In injuries of the brain, from blows and falls, the symptoms are usually alarming, and all should possess some information for such contingencies. In general, such accidents are attended by insensibility; the skin and extremities are pale and cold, the pulse is very weak and feeble, and the circulation is less vigorous; the respiration, also, is less frequent and full. 845. When these symptoms exist, the individual, in the first instance, should be placed in pure air, and friction and dry warmth should be applied to the pallid and cold skin. This should be assiduously persevered in until heat and color are restored to the skin and limbs, and due action of the heart and arteries has been established. Mild stimulants may also be used internally, with much advantage. The sympathizing friends should not be permitted to stand about the patient, as they vitiate the air. There should be no bleeding until the skin and extremities become warm. Send for a surgeon without delay. -=-=-=-=-=-=-=-=-=-=-=-= Give an instance where moderate concussion of the brain is produced. 844. What are the symptoms when the brain is injured from blows and falls? 845. What treatment should be adopted? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLI. THE SENSE OF TOUCH. 846. SENSATION is the perception of external objects by means of the senses. There are five senses, namely, _Touch_, _Taste_, _Smell_, _Hearing_, and _Vision_. 847. TOUCH is the sense by which the mind becomes acquainted with some of the properties of bodies, and enables us determine whether their surfaces are smooth or rough, their relative temperature, and, to a certain degree, their form and weight. 848. Some physiologists make a distinction between the sense of touch and tact. Tact, or feeling, is more general, extending over the whole surface of the skin and mucous membranes, while touch exists chiefly in the fingers of man and in the noses of certain quadrupeds. 849. "In the exercise of these functions, tact is considered passive; as, when any part of the system comes into contact with another body, a sensation of its presence is given, without the exercise of volition. On the contrary, touch is active, and is exercised voluntarily, for the purpose of conveying to the mind a knowledge of the qualities or properties of the surfaces of bodies; as when we feel of a piece of cloth to ascertain its qualities, or a polished surface, to prove its smoothness." 850. In man, the hand is admirably adapted to the exercise of touch. "The fineness of the skin, its great sensibility, the species of cushion formed by the sub-cutaneous fat at the extremities of the fingers, the length and flexibility of these organs, and the capability of opposing the thumb to the fingers, like a pair of forceps, are so many conditions essentially favorable to the delicacy of this sense, and enable us to appreciate with exactitude the qualities of the bodies we may feel." -=-=-=-=-=-=-=-=-=-=-=-= 846. Define sensation. How many senses have we? 847-851. _What is said of the sense of touch?_ 847. Define touch. 848. What is the difference between touch and tact? 849. In the exercise of these functions, which is active, and which passive? 850. Why is the hand so admirably adapted to the exercise of the sense of touch? -=-=-=-=-=-=-=-=-=-=-=-= 851. The nerves that supply the sense of touch, proceed from the anterior half of the spinal cord. Where this sense is most acute and delicate, we find the greatest number of sensitive nervous filaments, and those of the largest size. _Observation._ In amputating limbs, and other surgical operations, the division of the skin causes more pain than all the subsequent steps of the operation, however protracted. The muscles, cellular membrane, and fat have but little sensibility; while the bones, tendons, and ligaments are insensible when not diseased, and may be cut without causing pain. HYGIENE OF THE SENSE OF TOUCH. 852. The sense of touch varies in different persons, and also in individuals of different ages. Thus the sensibilities of the child are more acute than those of the aged. Although there is an original difference of sensibility from organization, still, the function of the nerves of sensation is modified by certain influences. 853. _The healthy or unhealthy, active or inactive state of the brain, influences the action of the sensitive nerves._ In sound and perfect sleep, the brain is inactive. In this state, ordinary impressions made upon the skin are not observed by the sleeping person. Thus the arm may be blistered while sleeping, when exposed to the warm rays of the sun, and the individual will not be aware of it at the time. -=-=-=-=-=-=-=-=-=-=-=-= 851. From what do the nerves proceed that supply this sense? 852-864. _Give the hygiene of the sense of touch._ 852. Does this sense vary in different persons? 853. Mention a condition of the brain that influences the nerves of sensation. -=-=-=-=-=-=-=-=-=-=-=-= 854. If there is compression of the brain, as when the skull-bones are depressed, or disease of this organ exists, as in severe typhus fever, impressions made upon the nerves of the skin will not be noticed. The same is true when the mind is engaged in intense thought or study; heat or cold may be so intense as to disorganize the skin, and not to be noticed. 855. The varying health or condition of the brain usually depresses or increases the sensitiveness of the skin. This is seen in grief and fear, which diminish, while hope and joy increase the impressibility of this tissue. It is not uncommon to see the unfortunate insane endure exposure to heat and cold with seeming impunity; whereas it would induce almost insupportable suffering to the sane man. Diseases of the heart, stomach, and lungs, alter the condition of the brain, and modify, to a greater or less degree, the sensitiveness of the skin. 856. _The state of the conducting nervous trunks influences the nerves of sensation._ If a nervous trunk is compressed or divided, the parts supplied by nervous filaments from this branch, will be insensible to the impressions made upon them, and consequently such impressions are not transmitted to the brain. _Observation._ When the inside of the arm or lower extremities rests upon a hard surface, the nerves may be compressed so as to deprive the parts of sensibility. This condition is called "numbness." 857. _The quantity of blood supplied to the skin modifies its sensitiveness._ If the quantity of blood is diminished, the sensibility of the skin will be impaired. This is demonstrated by noting the effects of cold upon the cutaneous tissue, the application of which contracts the blood-vessels, and drives the circulating fluid from this membrane, which is shown by the paleness, as well as by the shrivelled appearance of the skin. And, if this tissue is wounded while under the influence of cold, but little pain will be felt, and this chilling influence may be carried so far as not only to deprive the part of sensation, but of vitality. -=-=-=-=-=-=-=-=-=-=-=-= 854. Mention other conditions that affect these nerves. 855. What is the effect of the varying health or condition of the brain upon the sensitiveness of the skin? Give instances of this effect. 856. What is the result if a nervous trunk is divided or compressed? How may "numbness" in the limbs be produced? 857. Does the quantity of blood supplied to the skin affect its sensibility? -=-=-=-=-=-=-=-=-=-=-=-= 858. The influence of the blood upon the sensibility of the skin, is further demonstrated by the pain experienced when chilled extremities are suddenly exposed to heat. The nerves, by the sudden dilatation of the contracted blood-vessels, are put in vivid and rapid motion, which causes the painful and tingling sensation that we experience. In every part of the system, sudden changes produce unpleasant sensations, and frequently a diseased condition of the organs. _Observation._ When the hands, or other portions of the body, are frozen, or severely chilled, safety and comfort demand that circulation be restored to the parts by moderate exercise in a cool room. Not unfrequently, the vitality of the limb is destroyed by immersing it in hot water or holding it near the fire. 859. _The quality of the blood also influences sensation._ If the brain and other parts of the nervous system receive impure blood, their energy is depressed, and the sensibility of the skin rendered more or less obtuse. 860. _The condition of the cuticle modifies the impression made upon the cutaneous nerves._ 1st. When the cuticle has become thick and hard, like horn, as on the inside of the mason's hand, it enables him to ply his tools without much suffering, because the thickened cuticle diminishes the impressions made upon the nerves. -=-=-=-=-=-=-=-=-=-=-=-= How is it demonstrated? 858. How is the influence of the blood upon the skin further demonstrated? How should circulation be restored to limbs frozen or severely chilled? What should be avoided? 859. Show how the quality of the blood influences sensation. 860. Give the 1st condition of the cuticle that influences the impressions made on the cutaneous nerves. -=-=-=-=-=-=-=-=-=-=-=-= 861. 2d. When the cuticle is very thin and delicate, as on the hand of the lady who is unaccustomed to manual labor. Let her pursue some manual employment for several hours, and the extreme tenuity, or thinness of the cuticle, will not protect the nerves and parts below from becoming irritated and inflamed. 862. 3d. When the cuticle is removed by blistering or abrasion, the pain indicates that the naked nerves are too powerfully stimulated by the contact of external bodies. 4th. When the cuticle is coated with impurities, blended with the secretion from the oil-glands, the sensibility of the skin is lessened. 863. _The sensibility of the cutaneous nerves is modified by being habituated to impressions._ If, for example, an individual should immerse his feet in moderately warm water, at first it might induce a smarting sensation; in a short time, the nerves would not only become habituated to the warm water, but its warmth night be considerably increased. The same results follow, if an individual is exposed to a cold element. The impressions at first are highly disagreeable; but as soon as the nerves become accustomed to the surrounding atmosphere, it may impart the most agreeable sensations. _Illustration._ 1st. Let a person from the tropical regions go to a colder climate, and the cool mornings of the latter will at first affect him unpleasantly; but, after a few days' exposure to the cooler air, the sensation will be far from disagreeable. 2d. Let a person enter a room moderately heated; gradually increase the temperature, until it attains extreme summer heat; not only the cutaneous nerves, but the whole system, become habituated to the high temperature. From these facts we learn that the sensations, are not always a correct index of the real temperature. A well-adjusted thermometer will indicate it with unerring certainty. -=-=-=-=-=-=-=-=-=-=-=-= 861. The 2d condition. 862. The 3d and 4th condition. 863. Show how habit influences the sensibility of the cutaneous nerves. Give illustration 1st. Illustration 2d. -=-=-=-=-=-=-=-=-=-=-=-= 864. _Touch is modified, in a high degree, by education._ Thus the blind, whose "windows of the soul" are closed to the beauties of the external world, cultivate this sense to such a degree that they can distinguish objects with great accuracy. And the rapidity with which they read books prepared for their use, is a convincing proof of the niceness and extent to which the cultivation of this sense can be carried. _Illustrations._ 1st. The cloth-dresser, by the aid of this sense, distinguishes the quality, as well as the slightest difference of texture, in the different pieces of cloth. 2d. The miller, from a similar education, quickly detects the quality of flour or meal, by permitting it to pass between his fingers. The difference in the texture of cloths, or the quality of the flour, would not be distinguished by an individual whose tactile sense had not been trained to make nice comparisons. -=-=-=-=-=-=-=-=-=-=-=-= 864. Is this sense susceptible of improvement? What persons cultivate it to a high degree? Give illustration 1st. Illustration 2d. -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLII. SENSE OF TASTE. 865. The chief organ of TASTE is the upper surface of the tongue; though the lips, the palate, the internal surface of the cheeks, and the upper part of the oesophagus, participate in this function. ANATOMY OF THE ORGANS OF TASTE. 866. The tongue is a double organ, composed chiefly of muscular fibres, which run in almost every direction. The two sides are so perfectly distinct, that sometimes, in paralysis, one side is affected, while the function of the other remains perfect. It possesses great versatility of motion, and can be moulded into a great variety of shapes. In articulation, mastication, and deglutition, the tongue is an auxiliary to other organs. 867. This organ is abundantly supplied with blood-vessels, having a large artery sent to each side of it. It is also very largely furnished with nerves; it receives nervous filaments from the fifth, ninth, and twelfth pairs of nerves. The branch of the fifth, called the gustatory, is the nerve of taste and sensibility;[21] the twelfth, called the hypo-glossal, of voluntary motion. By means of the ninth, called the glosso-pharyngeal the tongue is brought into association with the fauces, oesophagus, and larynx. It is of obvious importance that these parts should act in concert; and this is effected by the distribution of this nerve. [21] Some physiologists impute the sense of taste to the ninth pair of nerves; others, to the twelfth pair; while others, again, contend that taste is the result of a concurrent action of the fifth, ninth, and twelfth pairs of nerves. -=-=-=-=-=-=-=-=-=-=-=-= 865. What is the chief organ of taste? What other parts participate in the function? 866-870. _Give the anatomy of the organs of taste._ 866. Give the structure of the tongue. 867. Is this organ abundantly supplied with blood? From what source does the tongue derive its nerves? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 134. A view of one side of the neck, showing the nerves of the tongue. 1, A fragment of the temporal bone. 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, Muscles of the tongue, fauces, and neck. 5, The tongue. 13, The common carotid artery. 14, The jugular vein. 15, The external carotid. 16, The internal carotid. 17, The gustatory branch of the fifth pair of nerves. 20, The glosso-pharyngeal nerve. 21, The hypo-glossal, or the muscular nerve of the tongue. 24, The pneumogastric nerve. 25, The facial nerve.] -=-=-=-=-=-=-=-=-=-=-=-= 868. What is the appearance of the surface of the tongue? Explain fig. 134. -=-=-=-=-=-=-=-=-=-=-=-= 868. The surface of the tongue is thickly studded with fine papillæ, or _vil´li_, which give the organ a velvety appearance. These papillæ are of three varieties. The first is situated near the base of the tongue. They belong to the class of mucous follicles. They are larger than the others, and are called _len-tic´u-lar_, from being shaped like a lens. These, together with the tonsils, (sometimes called the almonds of the ears,) secrete mucus, to lubricate the food in the act of deglutition. 869. The instruments of taste are the two other sets of papillæ. One set consists of small, oval-shaped bodies, which are scattered over the whole surface of the tongue. They give it a rough appearance, and are called the _fil´i-form_ papillæ. 870. The other set of papillæ is called the _fun´gi-form_. They are larger than the former, and consist of small, rounded heads, supported on short stalks, something in the shape of mushrooms, from which they derive their name. In the last two described sets of sensitive papillæ, the gustatory branch of the fifth pair of nerves ramifies. _Observation._ By applying strong acids, as vinegar, to the tongue, with a hair pencil, these points will become curiously lengthened. PHYSIOLOGY OF THE ORGANS OF TASTE. 871. TASTE is the sense which makes us acquainted with the savor of substances. When fluids are taken into the mouth, the papillæ dilate and erect themselves, and the particular impression excited is transmitted to the brain through filaments of the gustatory nerve. This sense is closely connected with that of smell. The pleasures derived from it are strictly sensual and corporeal, and contribute in no way to the expansion of the mind, like those of hearing and seeing. -=-=-=-=-=-=-=-=-=-=-=-= How many varieties of papillæ? Describe the first variety. What is the function of the lenticular papillæ? 869. Describe the filiform papillæ. 870. The fungiform papillæ? What nerve ramifies in the fungiform papillæ? How can these papillæ, or points, be seen? 871-875. _Give the physiology of the organs of taste._ 871. Define taste. -=-=-=-=-=-=-=-=-=-=-=-= 872. If dry, solid food is taken, the tongue carries it to the back side of the mouth, where it receives secretions from the salivary glands; the saliva, becoming impregnated with its flavor, flows over the sides of the tongue, and gives to the papillæ a perception of the savory juice; this impression is then communicated to the brain. _Observation._ It is supposed that the salts which enter into the composition of the saliva, are very efficient agents in reducing substances to a proper state for making impressions on the nerves of taste. The fact that metals impart a peculiar taste, is owing to a galvanic shock, and not properly to what we understand by taste. 873. The primary use of taste is to guide animals in the selection of food, and to warn them against the introduction of noxious articles into the stomach. In all the inferior animals, we see that the original design of taste is still answered. But in man, this sense has been so abused and perverted, by the introduction of stimulants and condiments, and the endless admixture of different articles of food, that the simple action of this part seems to have been superseded almost entirely by acquired taste. 874. In children, this sense is usually acute, and their preference is for food of the mildest character. And it is also true, that every person has some peculiarities of taste, or dislikes to particular articles of food. This may be either constitutional or from the influence of association. -=-=-=-=-=-=-=-=-=-=-=-= With what sense is this closely connected? What is said of this sense? 872. Give the process by which we taste substances. How can we account for the taste of metals when applied to the tongue? 873. What is the primary use of taste? Where do we see it perverted? 874. How is this sense in children? What is true of every person in reference to taste? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ This sense has been made to vary more than any other by the refinements of social life. Thus, the Indian's like or dislike to particular kinds of food, generally extends to every person of the same tribe; but among civilized men, no two individuals can be found alike in all their tastes. 875. This sense is modified by habit, and not unfrequently those articles, which at first were disgusting, become highly agreeable by persevering in the use of them. By cultivation, this sense may be made very acute. Those persons whose business leads them to judge of the quality of an article by their taste, can discriminate shades of flavor not perceivable by ordinary persons. Epicures, and tasters of wines and teas, afford examples. _Observation._ Many persons impair their taste by bad habits, as chewing and smoking tobacco, and using stimulating drinks, and pungent condiments with the food. These indulgences lessen the sensibility of the nerve, and destroy the natural relish for food. -=-=-=-=-=-=-=-=-=-=-=-= What is true of the Indian? 875. Is this sense modified by habit? Give instances. How is this sense sometimes impaired? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLIII. SENSE OF SMELL. 876. This sense is located in the air-passages of the _Nose_. To understand the function of smell, the structure of the nose and nasal cavities, with the distribution of the olfactory nerves, must be first examined. ANATOMY OF THE ORGANS OF SMELL. 877. The NOSE is composed of the _Bones_, _Fi´bro-car´tilages_, and _Mu´cous Mem´brane_, together with its integuments. 878. The BONES of the nose are the nasal, and the nasal processes of the upper jaw. 879. The FIBRO-CARTILAGES give form and stability to the framework of the nose, providing at the same time, by their elasticity, against injuries. They are five in number. 880. The MUCOUS MEMBRANE, which lines the interior of the nose, is continuous with the skin externally, and with the lining membrane of the parts of the throat. The entrance of the nostrils is provided with numerous hairs, which serve as guardians to the delicate membrane of the nose. 881. The NASAL FOSS�, or nostrils, are two irregular, compressed cavities, extending from the nose to the pharynx. These cavities are bounded superiorly by the sphenoid and ethmoid bones; inferiorly, by the hard palate. In the middle line they are separated from each other by a bony and fibro-cartilaginous septum; upon the outer wall of each fossa, in the dried skull, are three projecting processes, termed spongy bones. In the fresh fossa, these are covered by a mucous membrane. -=-=-=-=-=-=-=-=-=-=-=-= 876. Where is the sense of smell located? 877-884. _Give the anatomy of the organs of smell._ 877. Name the parts that enter into the structure of the nose? 878. What bones form the framework of the nose? 879. What is the use of the cartilages? 880. What relation has the mucous membrane with other membranes of the nose? 881. Describe the nasal cavities. -=-=-=-=-=-=-=-=-=-=-=-= 882. The space that intervenes between the superior and middle spongy bone, is called the _superior me-a´tus_, or channel; the space between the middle and inferior bone, is the _middle meatus_; and that between the inferior bone and the floor of the fossa, is the _inferior meatus_. [Illustration: Fig. 135. A vertical section of the middle part of the nasal cavities. 7, The middle spongy bones. 8, The superior part of the nasal cavities. 10, The inferior spongy bones. 11, The vomer. 12, The upper jaw. 13. The middle channel of the nose. 14, The lower channel of the nose. 17, The palatine process of the upper jaw-bone. 18, The roof of the mouth covered by mucous membrane. 19, A section of this membrane.] 883. The MEATUSES are passages that extend backward, from the nostrils, into which are several openings. They are lined by a mucous membrane, called the _pi-tu´i-ta-ry_, or _schneiderian_, from Schneider, who first showed that the secretion of the nasal fossæ proceeded from the mucous membrane, and not from the brain. -=-=-=-=-=-=-=-=-=-=-=-= 882. What terms are applied to the spaces between these processes? What does fig. 135 represent? 883. Define the meatuses. By what are they lined? -=-=-=-=-=-=-=-=-=-=-=-= 884. Upon the mucous membrane of the nasal passages, the olfactory nerve ramifies, and also a branch of the fifth pair of nerves. This membrane is of considerable extent in man; and in those animals whose sense of smell is very acute, it is still more extensive. [Illustration: Fig. 136. A side view of the passage of the nostrils, and the distribution of the olfactory nerve. 4, The olfactory nerve. 5, The fine and curious divisions of this nerve on the membrane of the nose. 6, A branch of the fifth pair of nerves.] PHYSIOLOGY OF THE ORGANS OF SMELL. 885. The sense of smell enables us to discern the odor or scent of any thing. When substances are presented to the nose, the air that is passing through the nostrils brings the odoriferous particles of matter in contact with the filaments of the olfactory nerves, that are spread upon the membrane that lines the air-passages, and the impression is then transmitted to the brain. -=-=-=-=-=-=-=-=-=-=-=-= 884. What nerves ramify upon this membrane? What is represented by fig. 136? 885-899. _Give the physiology of the organs of smell._ 885. How does the mind become sensible of odoriferous particles? -=-=-=-=-=-=-=-=-=-=-=-= 886. This sense, with that of taste, aids man as well as the inferior animals, in selecting proper food, and it also gives us pleasure by the inhalation of agreeable odors. The sense of smell, like that of taste and touch, may be improved by cultivation. It likewise varies in different persons. _Observation._ Sometimes this sense seems to possess a morbid degree of acuteness in respect to odors, which is highly inconvenient and even dangerous. With some individuals, the smell of certain fruits, flowers, cheese, &c., produce nausea and even convulsions. 887. In the inferior animals generally, the sense of smell is more acute than in man. Thus the bloodhound will track the hare over the ground for miles, guided only by the odor that it leaves in its flight. He also traces the progress of his master through thickly-crowded streets, distinguishing his footsteps from those of a thousand others, and amidst the odorous particles emanating from a thousand sources. _Observation._ In some of the higher orders of the inferior animals, there is an astonishing acuteness of smell in regard to effluvia that come from living animals. To these animals, it possesses an importance in them far beyond what it has in man, by making them acquainted with the presence of their enemies or their prey, when the eye and ear are incapable of acting. It is related by travellers in Africa, that they were always apprised of lions in their vicinity during the night, by the moans and tremblings of their horses. 888. Smell is somewhat under the control of the will. That is, we have the power of receiving or rejecting odors that are presented; thus, if odors are agreeable, we inspire forcibly, to enjoy them; but, if they are offensive, our inspirations are more cautious, or we close our nostrils. This sense is likewise modified by habit; odors which, in the first instance, were very offensive, may not only become endurable, but even agreeable. -=-=-=-=-=-=-=-=-=-=-=-= 886. What is the use of the sense of smell? Can this sense be improved by cultivation? What is said respecting this sense in some individuals? 887. What is said of this sense in the bloodhound? Mention an instance of astonishing acuteness of smell in some of the higher orders of animals. 888. Show that smell is somewhat under the control of the will. -=-=-=-=-=-=-=-=-=-=-=-= 889. Acuteness of smell requires that the brain and nerve of smell be healthy, and that the membrane that lines the nose be thin and moist. Any influence that diminishes the sensibility of the nerves, thickens the membrane, or renders it dry, impairs this sense. _Observations._ 1st. _Snuff_, when introduced into the nose, not only diminishes the sensibility of the nervous filaments, but thickens the lining membrane. This thickening of the membrane obstructs the passage of air through the nostrils, and thus obliges "snuff-takers" to open their mouths when they breathe. 2d. The mucous membrane of the nasal passages is the seat of chronic catarrh. This affection is difficult of removal, as remedial agents cannot easily be introduced into the windings of these passages. Snuff and many other articles used for catarrh, produce more disease than they remove. -=-=-=-=-=-=-=-=-=-=-=-= 889. On what does acuteness of smell depend? What effect has snuff when introduced into the nose? What is said of chronic catarrh? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLIV. SENSE OF VISION. 890. This sense contributes more to the enjoyment and happiness of man than any other of the senses. By it we perceive the form, color, volume, and position of objects that surround us. The eye is the organ of sight, or vision, and its mechanism is so wonderful, that it not only proves the existence of a great First Cause, but perhaps, more than other organs, the design of the Creator to mingle pleasure with our existence. ANATOMY OF THE ORGANS OF VISION. 891. The apparatus of vision consists of the _Op´tic Nerve_, the _Globe_ and _Muscles_ of the eye, and its _Protecting Organs_. 892. The OPTIC NERVE arises by two roots from the central portion of the base of the brain. The two nerves approach each other, as they proceed forward, and some of the fibres of each cross to the nerve of the opposite side. They then diverge, and enter the globe of the eyes at their back part, where they expand, and form a soft, whitish membrane. 893. The GLOBE, or ball of the eye, is an optical instrument of the most perfect construction. The sides of the globes are composed of _Coats_, or membranes. The interior of the globe is filled with refracting _Humors_, or _me´di-ums_. -=-=-=-=-=-=-=-=-=-=-=-= 890. Which sense contributes most to the enjoyment of man? What do we perceive by this sense? What is said of the mechanism of the eye? 891-916. _Give the anatomy of the organs of vision._ 891. Of what does the apparatus of vision consist? 892. Describe the optic nerve. 893. Describe the globe of the eye. -=-=-=-=-=-=-=-=-=-=-=-= 894. The COATS are three in number: 1st. The _Scle-rot´ic_ and _Corn´e-a_. 2d. The _Cho´roid_, _Iris_, and _Cil´ia-ry processes_. 3d. The _Ret´i-na_. 895 The HUMORS are also three in number: 1st. The _A´que-ous_, or watery. 2d. The _Crys´tal-line_, (lens.) 3d. The _Vit´re-ous_, or glassy. [Illustration: Fig. 137. The second pair of nerves. 1, 1, Globe of the eye: the one on the left is perfect, but that on the right has the sclerotic and choroid coats removed, to show the retina. 2, The crossing of the optic nerve. 5, The pons varolii. 6, The medulla oblongata. 7, 8, 9, 10, 11, 12, 13, The origin of several pairs of cranial nerves.] 896. The SCLEROTIC COAT is a dense, fibrous membrane and invests about four fifths of the globe of the eye. It gives form to this organ, and serves for the attachment of the muscles that move the eye in various directions. This coat, from the brilliancy of its whiteness, is known by the name of "the white of the eye." Anteriorly, the sclerotic coat presents a bevelled edge, which receives the cornea in the same way that a watch-glass is received by the groove in its case. -=-=-=-=-=-=-=-=-=-=-=-= 894. Name the coats of the eye. 895. Name the humors of the eye. Explain fig. 137. 896. Describe the sclerotic coat. -=-=-=-=-=-=-=-=-=-=-=-= 897. The CORNEA is the transparent projecting layer, that forms the anterior fifth of the globe of the eye. In form, it is circular, convexo-concave, and resembles a watch-glass. It is received by its edge, which is sharp and thin, within the bevelled border of the sclerotic, to which it is firmly attached. The cornea is composed of several different layers; its blood-vessels are so small that they exclude the red particles altogether, and admit nothing but serum. 898. The CHOROID COAT is a vascular membrane, of a rich chocolate-brown color upon its external surface, and of a deep black color within. It is connected, externally, with the sclerotic, by an extremely fine cellular tissue, and by the passage of nerves and vessels; internally, it is in contact with the retina. The choroid membrane is composed of three layers. It secretes upon its internal surface a dark substance, called _pig-ment´um ni´grum_, which is of great importance in the function of vision. 899. The IRIS is so called from its variety of color in different persons. It forms a partition between the anterior and posterior chambers of the eye, and is pierced by a circular opening, which is called the _pu´pil_. It is composed of two layers. The radiating fibres of the anterior layer converge from the circumference to the centre. Through the action of these radiating fibres the pupil is dilated. The circular fibres surround the pupil, and by their action produce contraction of its area. The posterior layer is of a deep purple tint, and is called _u-ve´a_, from its resemblance in color to a ripe grape. -=-=-=-=-=-=-=-=-=-=-=-= How are this coat and the cornea united? 897. Describe the cornea. 898. What is the color of the external surface of the choroid coat? Of the internal? How is it connected externally? How internally? What does this membrane secrete upon its internal surface? 899. Describe the iris. Of how many layers of fibres is the iris composed? What is the function of the radiating fibres? Of the circular? -=-=-=-=-=-=-=-=-=-=-=-= 900. The CILIARY PROCESSES consist of a number of triangular folds, formed, apparently, by the plaiting of the internal layer of the choroid coat. They are about sixty in number. Their external border is continuous with the internal layer of the choroid coat. The central border is free, and rests against the circumference of the crystalline lens. These processes are covered by a layer of the pigmentum nigrum. [Illustration: Fig. 138. A view of the anterior segment of a transverse section of the globe of the eye, seen from within. 1, The divided edge of the three coats--sclerotic, choroid, and retina. 2, The pupil. 3, The iris: the surface presented to view in this section being the uvea. 4, The ciliary processes. 5, The scalloped anterior border of the retina.] 901. The RETINA is composed of three layers: The external; middle, or nervous; and internal, or vascular. The external membrane is extremely thin, and is seen as a flocculent film, when the eye is suspended in water. The nervous membrane is the expansion of the optic nerve, and forms a thin, semi-transparent, bluish-white layer. The vascular membrane consists of the ramifications of a minute artery and its accompanying vein. This vascular layer forms distinct sheaths for the nervous papillæ, which constitute the inner surface of the retina. -=-=-=-=-=-=-=-=-=-=-=-= 900. How are the ciliary processes formed? What does fig. 138 exhibit? 901. Of how many layers is the retina composed? Describe the external layer. The nervous layer. -=-=-=-=-=-=-=-=-=-=-=-= 902. The AQUEOUS HUMOR is situated in the anterior and posterior chambers of the eye. It is an albuminous fluid, having an alkaline reaction. Its specific gravity is a very little greater than distilled water. The anterior chamber is the space intervening between the cornea, in front, and the iris and pupil, behind. The posterior chamber is the narrow space, less than half a line in depth, bounded by the posterior surface of the iris and pupil, in front, and by the ciliary processes and crystalline lens, behind. The two chambers are lined by a thin layer, the secreting membrane of the aqueous humor. 903. The CRYSTALLINE HUMOR, or lens, is situated immediately behind the pupil, and is surrounded by the ciliary processes. This humor is more convex on the posterior than on the anterior surface, and, in different portions of the surface of each, the convexity varies from their oval character. It is imbedded in the anterior part of the vitreous humor, from which it is separated by a thin membrane, and is invested by a transparent elastic membrane, called the capsule of the lens. The lens consists of concentric layers, disposed like the coats of an onion. The external layer is soft, and each successive one increases in firmness until the central layer forms a hardened nucleus. These layers are best demonstrated by boiling, or by immersion in alcohol, when they separate easily from each other. _Observations._ 1st. The lens in the eye of a fish is round, like a globe, and has the same appearance, when boiled, as the lens of the human eye. -=-=-=-=-=-=-=-=-=-=-=-= The vascular layer. 902. Where is the aqueous humor situated? What part of the eye is called the anterior chamber? The posterior chamber? With what are the chambers lined? 903. Where is the crystalline humor situated? With what is it surrounded? Of what does the lens consist? How are these layers best demonstrated? What is produced when the lens, or its investing membrane, is changed in structure? -=-=-=-=-=-=-=-=-=-=-=-= 2d. When the crystalline lens, or its investing membrane, is changed in structure, so as to prevent the rays of light passing to the retina, the affection is called a _cataract_. [Illustration: Fig. 139. A section of the globe of the eye. 1, The sclerotic coat. 2, The cornea (This connects with the sclerotic coat by a bevelled edge.) 3, The choroid coat. 6, 6, The iris. 7, The pupil. 8, The retina. 10, 11, 11, Chambers of the eye that contain the aqueous humor. 12, The crystalline lens. 13, The vitreous humor. 15, The optic nerve. 16, The central artery of the eye.] 904. The VITREOUS HUMOR forms the principal bulk of the globe of the eye. It is an albuminous fluid, resembling the aqueous humor, but is more dense, and differs from the aqueous in this important particular, that it has not the power of re-producing itself. If by accident it is discharged, the eye is irrecoverably lost; while the aqueous humor may be let out, and will be again restored. It is enclosed in a delicate membrane, called the _hy´a-loid_, which sends processes into the interior of the globe of the eye, forming the cells in which the humor is retained. -=-=-=-=-=-=-=-=-=-=-=-= 904. Describe the vitreous humor. How does this humor differ from the aqueous? What membrane encloses the vitreous humor? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ The structure of this organ can be seen by first freezing the eye of a sheep or an ox; it then can be cut in various directions, and each part separately examined. 905. The MUSCLES of the eye are six in number. They are attached, at one extremity, to the bones of the orbit behind the eye; at the other extremity, they are inserted by broad, thin tendons, near the junction of the cornea with the sclerotic coat. The white, pearly appearance of the eye is caused by these tendons. [Illustration: Fig. 140. A view of the eye and its muscles. _a_, _b_, _c_, _d_, _e_, Five of these muscles. _f_, The optic nerve. G, The trochlea, or pulley over which one of the muscles passes. The bone is seen above and below the eye.] _Observation._ If the external muscle is too short, the eye is turned out, producing the "wall eye." If the internal muscle is contracted, the eye is turned inward toward the nose. It is then called a "cross eye." -=-=-=-=-=-=-=-=-=-=-=-= 905. How many muscles has the eye? Give their attachments. What causes the pearly appearance of the eye? What does fig. 140 represent? What is the effect if the external muscle is contracted? The internal muscle? -=-=-=-=-=-=-=-=-=-=-=-= 906. The PROTECTING ORGANS are the _Or´bits_, _Eyebrows_, _Eyelids_, and _Lach´ry-mal Apparatus_. 907. The ORBITS are deep, bony sockets, in which the globes of the eyes are situated. They have the form of a cone, the base of which is open and directed forward. The bottom of the orbits is pierced by a large hole which gives passage to the optic nerve. These cavities are lined with a thick cushion of fat, in order that the eyes may move in all directions, with perfect freedom and without friction. 908. The EYEBROWS are two projecting arches of integument, covered with short, thick hairs, which form the upper boundary of the orbits. The eyebrows are so arranged that they prevent the moisture that accumulates on the forehead, in free perspiration, from flowing into the eye, and also shade these organs from too vivid light. 909. The EYELIDS are two movable curtains placed in front of the eye. They have a delicate skin on the outside, muscular fibres beneath, and a narrow cartilage on their edges, which tends to preserve the shape of the lid. Internally, they are lined by a smooth membrane, which is reflected over the front of the eye upon the sclerotica. This membrane is called the _con-junc-ti´va_. It secretes the fluid that moistens and lubricates the eye, and which causes the eyelids to open and shut without friction. _Observation._ When the portion of this membrane that is reflected over the globe of the eye, is inflamed, there is frequently a deposition of whitish material, called lymph. This accounts for the films, opacities, and white spots seen upon the eye after the inflammation has subsided. -=-=-=-=-=-=-=-=-=-=-=-= 906. Name the protecting organs of the eye. 907. Describe the orbits. How are the movements of the eye facilitated? 908. Describe the eyebrows. What does this arrangement prevent? 909. Describe the eyelids. What is the use of the conjunctiva? How are the white spots frequently seen upon the eye accounted for? -=-=-=-=-=-=-=-=-=-=-=-= 910. There are found several small glands on the internal surface of the cartilage, which have the appearance of parallel strings of pearls. They open by minute apertures upon the edges of the lids. The secretion from these glands prevents the edges of the eyelids from being united during sleep. 911. The edges of the eyelids are furnished with a triple row of long, thick hairs, called _eyelashes_, which curve upward from the upper lid, and downward from the lower, so that they may not interlace with each other in the closure of the eyelids. These appendages of the eye, by closing, not only protect it from moisture, but from dust, particularly during sleep. They likewise, by their movements in opening and shutting, spread the lubricating fluid equally over the eye. 912. The LACHRYMAL APPARATUS, which secretes the tears, consists of the _Lachrymal Gland_ with its ducts, _Lachrymal Canals_, and the _Nasal Duct_. 913. The LACHRYMAL GLAND is situated at the upper and outer angle of the orbit. It is about three quarters of an inch in length, flattened and oval in shape, and occupies a depression in the orbital plate of the frontal bone. Ten or twelve small ducts pass from this gland, and open upon the upper eyelid, where they pour upon the conjunctiva the lachrymal fluid, or tears. This secretion is maintained while we are asleep, as well as when we are awake. The eye from this cause is kept constantly moist. 914. The LACHRYMAL CANALS commence at minute openings upon the free borders of each eyelid, near the internal angle of the eye, by two small orifices, called _punc´ta lach-ry-ma´li-a_, (tear points.) Each of these points communicate with the sac at the upper part of the nasal duct. -=-=-=-=-=-=-=-=-=-=-=-= 910. What are found on the internal surface of the cartilage of the eyelids? Where do they open, and what is their use? 911. With what are the edges of the eyelids furnished? What are their uses? 912. Of what does the lachrymal apparatus consist? 913. Describe the lachrymal gland. How many ducts pass from this gland, and what do they convey to the eye? Why is the eye constantly moist? 914. Where do the lachrymal canals commence? -=-=-=-=-=-=-=-=-=-=-=-= 915. The NASAL DUCT is a short canal, about three quarters of an inch in length, directed downward and backward to the inferior channel of the nose, where it terminates by an expanded orifice. [Illustration: Fig. 141. 1, The lachrymal gland. 2, Ducts leading from the lachrymal gland to the upper eyelid. 3, 3, The puncta lachrymalia. 4, The nasal sac. 5, The termination of the nasal duct.] 916. The fluid (tears) secreted by the lachrymal gland, is conveyed to the eye by the small ducts before described. It is then imbibed by the puncta lachrymalia, and carried by the lachrymal canals into the lachrymal sac, from which it is passed to the nasal cavities by the nasal ducts. -=-=-=-=-=-=-=-=-=-=-=-= What are they called? With what do they communicate? 915. Describe the nasal duct. 916. How are the tears conveyed from the lachrymal gland to the nose? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLV. PHYSIOLOGY OF THE ORGANS OF VISION. 917. To comprehend the theory of vision, it is not sufficient to know the structure of the eye. We must be familiar with some of the properties of a subtile fluid, which is constantly emanating from all luminous bodies, called _light_. 918. It is the province of natural philosophy, rather than physiology, to enter minutely upon the properties of light. It may be observed, however, that, when light passes through any medium of the same density, the rays are in straight lines; but, when it passes from one medium into another of different density, it is refracted, or turned from a straight course, unless it strikes the medium in a perpendicular direction--then light passes through without a change of direction. 919. When a ray of light meets with a body, it either passes through it, or is reflected by it, or it may be absorbed. Again, in proportion as the rays of light become distant from the body from which they emanate, they diverge one from the other. In accordance with the laws of optics, the rays of light, in passing through an optical instrument like the eye, must cross each other, and thus produce an inverted image of the object from which the rays proceed. With the general view of the structure of the eye, we will now examine the use of each part in the function of vision. -=-=-=-=-=-=-=-=-=-=-=-= 917-933. _Give the physiology of the organs of vision._ 917. What is necessary in order to understand the theory of vision? 918. When light passes through a medium of the same density, in what direction will be its rays? Of a different density? What exception? 919. When light meets with a body, what takes place? What is said in reference to rays of light in passing through the eye? -=-=-=-=-=-=-=-=-=-=-=-= 920. The sclerotic coat not only gives form to the body of the eye, but protection to the interior and more delicate parts. The choroid coat seems to be chiefly composed of a tissue of nerves and minute blood-vessels; the latter give nourishment to the different parts of the eye. One of the uses of this coat is, to absorb the rays of light immediately after they have passed through the retina. This is effected by the black pigment that lines its inner surface. Were it not for this provision, light would be too intense, and vision indistinct. _Observation._ In albinos, where there is an absence of the black pigment, the rays of light traverse the iris, and even the choroid coat, and so overwhelm the eye with light, that their vision is quite imperfect, except in the dimness of evening, or at night. In the manufacture of optical instruments, care is taken to color their interior black, for the same object, namely, the absorption of scattered rays. 921. The iris, by means of its powers of expansion and contraction, regulates the quantity of light admitted through the pupil. If the iris is thin, and the rays of light pass through its substance, they are immediately absorbed by the uvea, and, if that layer be insufficient, they are taken up by the black pigment of the choroid coat. _Observation._ When we look toward the bottom of the eye, the pupil appears like a black spot, instead of an opening. This is caused by seeing the black pigment through the retina and humors of the eye. -=-=-=-=-=-=-=-=-=-=-=-= 920. What is the use of the sclerotic coat? Of what is the choroid coat chiefly composed? What is the use of this coat? How is it effected? What is said of albinos? What care is taken in the manufacture of optical instruments? 921. What is the use of the iris? When we look toward the bottom of the eye, why does the pupil look like a black spot, instead of an opening? -=-=-=-=-=-=-=-=-=-=-=-= 922. The cornea, and the aqueous, crystalline, and vitreous humors, are transparent; so that rays of light traverse these parts of the eye, and fall upon the retina. The office of these humors and the cornea is to refract the rays of light in such proportion as to direct the image in the most favorable manner upon the retina. 923. The office of the retina is to receive the impression of the rays of light which leave an object at which we look, and it is upon it that a small but very clear image of that object is formed. The impression thus produced by the reflected light is transmitted by the optic nerve to the brain, which receives the sensation. This constitutes vision. 924. The optic nerve has but one function, that of sight. Sensibility is conferred on this organ by a large branch from the fifth pair of nerves, which ramifies upon the different parts of the eye and its appendages. These parts, however, receive some nervous filaments from the seventh pair. _Observations._ 1st. The large number of sensitive nervous filaments renders the visual organ very impressible to bodies that cause irritation, as dust, or intense light. This compels us to use due care to shield the eye from the influence of agents that would impair or destroy vision. 2d. Although particles of dust, when in contact with the delicate parts of the eye, induce severe pain, yet these parts may be cut in surgical operations, and the patient's sufferings are not as great as when an incision is made in the skin to remove a small tumor. 925. Different degrees of density, as already mentioned, modify the refractory power of any transparent medium. It is found, on examination, that the cornea, the vitreous, the crystalline, and the aqueous humors, have each, severally, various degrees of density: and that the crystalline lens, at its circumference, is less dense than at its centre. These circumstances modify the direction of the refraction of the rays of light, in their passage from the cornea to the retina. -=-=-=-=-=-=-=-=-=-=-=-= 922. What is the use of the cornea, aqueous, crystalline, and vitreous humors? 923. What is the office of the retina? 924. What is the function of the optic nerve? How is sensibility conferred on this organ? Give the 1st observation in this connection. The 2d observation. -=-=-=-=-=-=-=-=-=-=-=-= 926. The refracting powers of the plane, convex, concave, plano-convex, plano-concave, and concavo-convex lenses,[22] are different. The cornea and aqueous humors are convexo-concave, the vitreous humor is concavo-convex, while the crystalline humor is a convexo-convex medium. (Fig. 139.) [22] The refracting character of differently-formed lenses is illustrated in the works on Natural Philosophy, to which the pupil is referred. [Illustration: Fig. 142. The forms of the different lenses. 1, A plane lens. 2, A globe lens. 3, A convexo-convex lens. 4, A plano-convex lens. 5, A concavo-concave lens. 6, A plano-concave lens. 7, Meniscus. 8, A concavo-convex lens.] -=-=-=-=-=-=-=-=-=-=-=-= 925. Have the cornea and the humors of the eye different degrees of density? What is said of the crystalline lens? What effect has the different density of the parts of the eye upon the light admitted to this organ? 926. What kind of lenses do the humors exhibit? 927. What modifies the refracting powers of transparent mediums? How does this principle apply to the humors of the eye? -=-=-=-=-=-=-=-=-=-=-=-= 927. The different degrees of convexity or concavity also modify the refracting character of transparent mediums. The crystalline lens is of different degrees of convexity on its two sides. The convex surfaces of the aqueous and vitreous humors are segments of circles, of different diameters from their concave surfaces. (Fig. 139.) All these circumstances still further influence the refracting character of the visual organ. The achromatic arrangement of the transparent refracting mediums of the eye, remedies the aberration of refraction in the different portions of the eye. 928. Again, the refracting power of lenses is modified by their convexity or concavity. The more convex a lens is, the shorter the distance from the refracting medium, where the different refracted rays converge to a focus. To adapt the eye to view objects at different distances, requires a change in the refracting power of some of the transparent mediums of the eye. 929. Both surfaces of the crystalline lens are oval, not spherical, and the refraction of the rays of light is mainly effected in this portion of the eye. Change the inclination of this lens, so that different portions of its anterior surface shall be directly behind the pupil, and its refracting power is increased or diminished, as the surface presented is more or less convex. 930. To view objects at a distance, a less convex lens is needed than in examining articles very near the eye; and this organ, from its structure, has the power of adaptation to different distances. It is supposed that the muscular substance of the ciliary body and processes changes, by its contraction, the inclination of the crystalline lens. Without this, or some other adapting power, a picture of objects at different distances would not be formed upon the retina, and the vision of every person would be defective, except in reference to objects at certain definite distances from the eye. -=-=-=-=-=-=-=-=-=-=-=-= 928. What modifies the refracting power of lenses? What is necessary to adapt the eye to view objects at different distances? 929. Where is the refraction of the rays of light mainly effected? 930. When we view objects at a distance, what kind of lens is required? Has the eye the power of adapting itself to different distances? How is it effected? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ It is well known that a separate image is formed on each eye, and, if they are not in the same direction, the objects will appear double. This is proved by pressing one eye, so that the rays of light cannot enter it in the same direction as they do in the other; consequently, the vision is double. 931. By the action of the muscles of the eye, it is turned in different directions, so that objects can be examined upon each side, as well as in front, without turning the body. By the slight or intense action of the straight muscles, the eye is more or less compressed, and the form of the globe is changed, together with the relative positions of the different humors. This modification also adapts the eye to view objects at different distances. [Illustration: Fig. 143. 1, A pen, an inverted image of which is painted on the retina of the eye, at 2. The image of all objects upon the expansion of the optic nerve, is inverted by the crossing of the rays of light from objects as they traverse the pupil.] _Observation._ If the eye is fixed for a time on some object which is distinguished with difficulty, there is a painful sensation, similar to that experienced by other muscles of the body when used too long. This is called "straining the eye." 932. When the refraction of the rays of light is too great, as in over-convexity of the cornea, or the crystalline lens, or the vitreous humor, or all of them, the image is formed a little in front of the retina. Persons thus affected cannot see distinctly, except at a very short distance. This infirmity is called _near_, or _short-sightedness_. This defect is in a great measure obviated by the use of concave glasses, which scatter the luminous rays, and thus counterbalance the too strong refracting force of the eye. -=-=-=-=-=-=-=-=-=-=-=-= What does fig. 143 represent? 931. Why can we see objects at the side as well as in front of the eye, without turning the body? What is the effect when the eye is fixed on an object that is indistinctly seen? -=-=-=-=-=-=-=-=-=-=-=-= 933. When the different parts of the eye are not sufficiently convex, the image is formed beyond the retina, and thus only distant objects are distinctly seen. This defect is called _long-sightedness_. The feebleness in the refracting power of the eye may be caused by disease; but usually it is a consequence of old age, and is remedied by wearing spectacles with convex glasses. HYGIENE OF THE ORGANS OF VISION. 934. _The eye, like other organs of the body, should be used, and then rested._ If we look intently at an object for a long time, the eye becomes wearied, and the power of vision diminished. The observance of this rule is particularly needful to those whose eyes are weak, and predisposed to inflammation. On the contrary, if the eye is not called into action, its functions are enfeebled. 935. _Sudden transitions of light should be avoided._ The iris enlarges or contracts, as the light that falls upon the eye is faint or strong; but the change is not instantaneous. Hence the imperfect vision in passing from a strong to a dim light, and the overwhelming sensation experienced on emerging from a dimly-lighted apartment to one brilliantly illuminated. A common cause of _am-aur-o´sis_, or paralysis of the retina, is, using the eye for a long time in a very intense light. -=-=-=-=-=-=-=-=-=-=-=-= 932. What is short-sightedness? How is the defect remedied? 933. What is long-sightedness? How is the defect remedied? 934-942. _Give the hygiene of the organs of vision._ 934. Do the same principles apply to the use of the eye as to other organs? What is the effect if the eye is fixed intently on an object for a long time? What results if the eye is not called into action? 935. Why should sudden transitions of light be avoided? -=-=-=-=-=-=-=-=-=-=-=-= _Note._ Let the anatomy and physiology of the eye be reviewed from figs. 139 and 143, or from anatomical outline plate No. 10. 936. _Long-continued oblique positions of the eye should be avoided, when viewing objects._ If the eye is turned obliquely for a long time in viewing objects, it may produce an unnatural contraction of the muscle called into action. This contraction of the muscle is termed _stra-bis´mus_, or cross-eye. The practice of imitating the appearance of a person thus affected, is injudicious, as the imitation, designed to be temporary, may become permanent. _Observation._ The vision of a "cross-eye" is always defective. In general, only one eye is called into action, in viewing the object to which the mind is directed. This defect can be remedied by a surgical operation, which also corrects the position of the eye. 937. _Children should be trained to use the eye upon objects at different distances._ This is necessary, in order that the vision may be correct when objects at various distances are viewed. Any action unnatural to the muscles, if frequently repeated, may and will modify the character and action of the parts so operated upon. If a limb, as the arm, be kept flexed for a long time, one set of muscles will be relaxed and elongated, and another will be shortened, and its contractile power will be increased. The same principle is true of the eye. -=-=-=-=-=-=-=-=-=-=-=-= What causes palsy of the retina? 936. Why should we avoid oblique positions of the eye in viewing objects? What is said of the practice of imitating persons thus affected? What is said in reference to the vision of a "cross-eye"? 937. Why should children be trained to use the eye upon objects at different distances? What is the effect if an unnatural action of the muscles is frequently repeated? Does the same principle apply to the eye? -=-=-=-=-=-=-=-=-=-=-=-= 938. In viewing objects very near the eye, the ciliary processes are called into action to produce a proper inclination of the crystalline lens, so that the rays of light may be properly refracted to form a perfect image on the retina. In looking at objects at a great distance, the ciliary processes are called into a different action, to produce a different inclination of the lens. Let either of these actions be repeated, again and again, for weeks and months, and they will become natural, and the acquired inclination will be permanent. 939. From the preceding principle, a person becomes short or long sighted, as the objects to which the eye is usually directed are near or remote. This is one reason why scholars, watchmakers, and artisans, who bring minute objects near the eye to examine them, are short-sighted, and why hunters and sailors, who are habituated to view objects at a distance, are long-sighted. _Observation._ In the management of children, whether in the nursery or school-room, it is very important that their books, or articles upon which they may labor, should be held at an appropriate distance from the eye. Were this attended to by the parent or instructor, we should not see so many persons with defective vision. 940. Cleanliness, as well as the health of the eye, require that it be bathed every morning with pure water, either cold or tepid, accompanied with as little rubbing or friction as possible. In all instances, the secretion from the lachrymal glands, that sometimes collects at the angle of the eye, should be removed, as it contains saline matter. 941. When small particles, or dust, get upon the eye, they produce much inconvenience, which is often increased by harsh attempts to remove them. The individual should be placed before a strong light, the lids held open with one hand, or by another person, and the particles removed with the corner of a fine linen or silk handkerchief. -=-=-=-=-=-=-=-=-=-=-=-= 938. What is the effect of repeatedly using the eye in one direction? 939. Why are artisans and scholars generally short-sighted? Why are sailors and hunters long-sighted? How can defective vision in a great degree be prevented? 940. What reasons are there for bathing the eye? 941. How can dust and other small particles be removed from the eye? -=-=-=-=-=-=-=-=-=-=-=-= 942. Sometimes the substance is concealed under the upper eyelid, and it may then be exposed by turning back the lid in the following manner: Take a knitting-needle, or small, slender piece of stick, which is perfectly smooth, and place it over the upper lid, in contact with, and just under the edge of the orbit; then, holding it firmly, seize the eyelashes with the fingers of the disengaged hand, and gently turn the lid back over the stick or needle. The inner side of the lid can then be examined, and any substance removed that may have been there concealed. Too many trials ought not to be made, if unsuccessful, as much inflammation may be induced; but a surgeon should be consulted as soon as possible. _Observation._ Eyestones ought never to be placed in the eye, as they often cause more pain and irritation than the evil which they are intended to remedy. -=-=-=-=-=-=-=-=-=-=-=-= 942. How removed from the upper eyelid? Why should not eyestones be used? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLVI. THE SENSE OF HEARING. 943. The sense of hearing is next in importance to that of vision. Through this sense we are enabled to perceive sounds, that not only subserve to our comfort and pleasure, but are instrumental in promoting our intellectual enjoyments. The organ of hearing, or the ear, is one of the most complicated in the human body. ANATOMY OF THE ORGANS OF HEARING. 944. The EAR is composed of three parts: 1st. The _External Ear._ 2d. The _Tym´pan-um_, or middle ear. 3d. The _La´by-rinth_, or internal ear. 945. The EXTERNAL EAR is composed of two parts: The _Pin´na_, (pavilion of the ear,) and the _Me-a´tus Aud-it-o´ri-us Ex-ter´nus_, (auditory canal.) 946. The PINNA is a cartilaginous plate which surrounds the entrance of the auditory canal. It presents many ridges and furrows, arising from the folds of the cartilage that form it. _Observation._ The pinna, in many animals, is movable; in those that pursue their prey, it is generally directed forward; in timid animals, as the hare and rabbit, it is directed backward. In man, this part is but slightly under the control of the will. -=-=-=-=-=-=-=-=-=-=-=-= 943. What is said of the importance of hearing? Is the ear complicated in its structure? 944-962. _Give the anatomy of the organs of hearing._ 944. Of how many parts is the ear composed? Name them. 945. Give the parts of the external ear. 946. Describe the pinna. What is said in reference to the pinna of many animals? -=-=-=-=-=-=-=-=-=-=-=-= 947. The MEATUS AUDITORIUS is a canal partly cartilaginous, and partly bony, about an inch in length, which extends inward from the pinna to the _Mem´bra-na Tym´pan-i_, (drum of the ear.) It is narrower in the middle than at the extremities. It is lined by an extremely thin pouch of cuticle, which, when withdrawn, after maceration, preserves the form of the canal. Some stiff, short hairs are also found in the interior of the channel, which stretch across the tube, and prevent the ingress of insects. Beneath the cuticle are a number of small follicles, which secrete the wax of the ear. [Illustration: Fig. 144. A representation of the four bones of the ear. The smallest is highly magnified. This bone is early matured, and in the adult it becomes united with the incus. These bones are retained in their places and moved by three ligaments and four muscles.] 948. The MEMBRANA TYMPANI is a thin, semi-transparent membrane, of an oval shape. It is about three eighths of an inch in diameter, and is inserted into a groove around the circumference of the meatus, near its termination. This membrane is placed obliquely across the area of that tube. It is concave toward the meatus, and convex toward the tympanum. 949. The TYMPANUM consists of an irregular bony cavity, situated within the temporal bone. It is bounded externally by the membrana tympani; internally by its inner wall; and in its circumference by the petrous portion of the temporal bone and mastoid cells. The tympanum contains four small bones, called the _os-sic´u-la au-di´tus_. These are named separately, the _mal´le-us_, _in´cus_, _sta´pes_, and _or-bic´u-lar_. -=-=-=-=-=-=-=-=-=-=-=-= 947. What is the meatus auditorius? What is found in this canal? What is their use? Where is the wax of the ear secreted? 948. Describe the membrana tympani. 949. Where is the tympanum situated? -=-=-=-=-=-=-=-=-=-=-=-= 950. There are ten openings in the middle ear; five large and five small. The larger openings are, the _Me-a´tus Aud-it-o´ri-us Ex-ter´nus_, _Fe-nes´tra O-va´lis_, (oval window,) _Fe-nes´tra Ro-tun´da_, (round window,) _Mas´toid Cells_, and _Eu-sta´chi-an Tube_. [Illustration: Fig. 145. A representation of the pinna, meatus, membrana tympani, bones of the ear, and semicircular canals. _a_, The pinna. _c_, The meatus auditorius externus. _g_, The membrana tympani. _k_, The tympanum. _e_, The bones of the ear. _b_, The semicircular canals. _f_, The cochlea. _h_, The vestibule. _i_, The Eustachian tube. _d_, The auditory nerve.] 951. The FENESTRA OVALIS is the opening of communication between the tympanum and the vestibule. It is closed by the foot of the stapes, or bone of the ear, and by the lining membrane of both cavities. 952. The FENESTRA ROTUNDA serves to establish a communication between the tympanum and the cochlea. it is closed by a proper membrane, as well as by the lining of both cavities. -=-=-=-=-=-=-=-=-=-=-=-= What does this cavity contain? 950. How many openings in the tympanum? Explain fig. 145. 951. Describe the fenestra ovalis. 952. The fenestra rotunda. -=-=-=-=-=-=-=-=-=-=-=-= 953. The MASTOID CELLS are very numerous, and occupy the whole of the interior of the mastoid process of the temporal bone, and part of the petrous bone. They communicate, by a large, irregular opening, with the upper and posterior circumference of the tympanum. [Illustration: Fig. 146. A view of the labyrinth laid open. This figure is highly magnified. 1, 1, The cochlea. 2, 3, Two channels, that wind two and a half turns around a central point, (5.) 7, The central portion of the labyrinth, (vestibule.) 8, The foramen rotundum. 9, The fenestra ovalis. 11, 12, 13, 14, 15, 16, 17, 18, The semicircular canals. The cochlea and semicircular canals open into the vestibule.] 954. The EUSTACHIAN TUBE is a canal of communication, extending obliquely between the pharynx and the anterior circumference of the tympanum. In structure it is partly fibro-cartilaginous and partly bony. It is broad and expanded at its pharyngeal extremity, and narrow and compressed at the tympanum. -=-=-=-=-=-=-=-=-=-=-=-= 953. Where are the mastoid cells? Explain fig. 146. 954. Describe the Eustachian tube. -=-=-=-=-=-=-=-=-=-=-=-= 955. The small openings of the middle ear are for the entrance and exit of the chorda tympani, (a small nerve that crosses the tympanum,) and for the exit of the muscles that act upon the membrana tympani and bones of the ear. 956. The LABYRINTH consists of a membranous and a bony portion. The bony labyrinth presents a series of cavities which are channelled through the substance of the petrous bone. It is situated between the cavity of the tympanum and the _Aud´it-o-ry Nerve_. The labyrinth is divided into the _Ves´ti-bule_, _Sem-i-cir´cu-lar Canals_, and _Coch´le-a_. 957. The VESTIBULE is a small, three-cornered cavity, situated immediately within the inner wall of the tympanum. 958. The SEMICIRCULAR CANALS are three bony passages which communicate with the vestibule, into which two of them open at both extremities, and the third at one extremity. 959. The COCHLEA forms the anterior portion of the labyrinth. It consists of a bony and gradually tapering canal, about one and a half inches in length, which makes two turns and a half, spirally, around a central axis, called the _mo-di´o-lus_. The modiolus is large near its base, where it corresponds with the first turn of the cochlea, and diminishes in diameter toward its extremity. 960. The interior of the canal of the cochlea is partially divided into two passages, by means of a bony and membranous plate. At the extremity of the modiolus, the two passages communicate with each other. At the other extremity, one opens into the vestibule; the other into the tympanum, by the foramen rotundum. The internal surface of the bony labyrinth is lined by a fibro-serous membrane. -=-=-=-=-=-=-=-=-=-=-=-= 955. What passes through the small openings of the middle ear? 956. Of what does the labyrinth consist? Give the parts of the internal ear. 957. Describe the vestibule. 958. What is said of the semicircular canals? 959. Why is the cochlea so called? Of what does it consist? 960. How is the interior of the canal of the cochlea divided? Where do they communicate with each other? -=-=-=-=-=-=-=-=-=-=-=-= 961. The membranous labyrinth is smaller in size, but a perfect counterpart, with respect to form, of the bony vestibule, cochlea, and semicircular canals. Within this labyrinth are two small, elongated sacs, which are filled with a fluid. [Illustration: Fig. 147. A view of the auditory nerve. 1, The spinal cord. 2, The medulla oblongata. 3, The lower part of the brain. 4, The auditory nerve. 5, A branch to the semicircular canals. 6, A branch to the cochlea.] 962. The AUDITORY NERVE enters the temporal bone upon its internal surface, and divides into two branches, at the bottom of the cavity of the internal ear. These branches enter the structure of the elongated sacs and membranous labyrinth, radiating in all directions, and finally, they terminate upon the inner surface of the membrane, in minute papillæ, resembling those of the retina. -=-=-=-=-=-=-=-=-=-=-=-= By what is the internal labyrinth lined? 961. Describe the membranous labyrinth. What does fig. 147 represent? 962. Where does the auditory nerve enter and divide? Where do the branches of the auditory nerve enter and terminate? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLVII. PHYSIOLOGY OF THE ORGANS OF HEARING. 963. HEARING is that function by which we obtain a knowledge of the vibratory motions of bodies, which constitute sounds. The precise function of all the different parts of the ear is not known. 964. The function of that part of the external ear which projects from the head is to collect sounds and reflect them into the meatus. 965. The membrana tympani serves to facilitate the transmission of sounds, and also to moderate their intensity. It is so arranged that it can be relaxed or tightened. _Observation._ This membrane, when healthy, has no opening; and it must be apparent that the apprehension which is often expressed, that insects will penetrate further, is groundless. The pain is owing to the extreme sensibility of the membrana tympani. 966. The supposed office of the tympanum is to transmit the vibrations made on the membrana tympani to the internal ear. This is effected by the air which it contains, and by the chain of small bones that are enclosed in this cavity. 967. The use of the Eustachian tube is to admit air into the tympanum, which renders the pressure on both sides equal, and thus its membrane is kept in a proper state of tension. -=-=-=-=-=-=-=-=-=-=-=-= 963-971. _Give the physiology of the organs of hearing._ 963. What is hearing? Are the precise functions of the different parts of the ear known? 964. What is the function of the external ear? 965. Of the membrana tympani? What observation in reference to this membrane? 966. What is the supposed office of the middle ear? 967. What is the use of the Eustachian tube? -=-=-=-=-=-=-=-=-=-=-=-= _Observation._ When near a cannon, or a field-piece, about being discharged, by opening the mouth the impression upon the auditory nerve will be diminished, and the unpleasant sensation lessened. This is the result of the air in the middle ear escaping through the Eustachian tube, when the vibrations of the membrana tympani are violent. [Illustration: Fig. 148. A view of all the parts of the ear. 1, The tube that leads to the internal ear. 2, The membrana tympani. 3, 4, 5, The bones of the ear. 7, The central part of the labyrinth, (vestibule.) 8, 9, 10, The semicircular canals. 11, 12, The channels of the cochlea. 13, The auditory nerve. 14, The channel from the middle ear to the throat, (Eustachian tube.)] 968. But little is known of the functions of the internal ear; its parts are filled with a watery fluid, in which the filaments of the auditory nerve terminate. -=-=-=-=-=-=-=-=-=-=-=-= What observation in this connection? 968. What is the function of the internal ear? -=-=-=-=-=-=-=-=-=-=-=-= 969. Many of the parts just enumerated aid in hearing, but are not absolutely essential to this sense. But if the vestibule and auditory nerve are diseased or destroyed, no sound is then perceived. If this sense is destroyed in early life, the person also loses the power of articulating words. Hence a man born deaf is always dumb. 970. The transmission of sound through the different parts of the ear will now be explained by aid of fig. 148. The vibrations of air are collected by the external ear, and conducted through the tube (1) to the membrana tympani, (2.) From the membrane vibrations pass along the chain of bones, (3, 4, 5.) The bone 5 communicates with the internal ear, (7, 8, 9, 10, 11, 11, 11, 12, 12, 12.) From the internal ear the impression is transmitted to the brain by the nerve, (13.) 971. The auditory nerve, like the optic, has but one function, that of special sensibility. The nerves which furnish the ear with ordinary sensibility, proceed from the fifth pair. HYGIENE OF THE ORGANS OF HEARING. 972. Hearing, like the other senses, is capable of very great improvement. By cultivation, the blind are enabled to judge with great accuracy the distance of bodies in motion, and even the height of buildings. It is also capable of improvement when all the other senses are perfect. Thus the Indian will distinguish sounds that are inaudible to the white man. -=-=-=-=-=-=-=-=-=-=-=-= 969. What parts of the ear are essential in order to hear sounds? What follows loss of hearing? 971. What is the office of the auditory nerve? What nerves convey ordinary sensibility to the ear? 972-978. _Give the hygiene of the organs of hearing._ 972. Is this sense capable of improvement? How does this sense aid the blind? Is it also capable of improvement when all the other senses are perfect? In whom is this illustrated? -=-=-=-=-=-=-=-=-=-=-=-= _Note._ Let the anatomy and physiology of the organs of hearing be reviewed, from fig. 148, or from anatomical outline plate No. 10. 973. Acute hearing requires perfection in the structure and functions of the different parts of the ear, and that portion of the brain from which the auditory nerve proceeds. Deafness is by no means unfrequent. We will now advert to some of the common causes of imperfect hearing. 974. The structure or functional action of the brain may be deranged by inflammation, by compression, or by debility, and produce deafness. The first is seen during inflammatory affections of the brain, and in fevers; the second is seen in accidental injuries of the head; the third is seen in old age, and after severe diseases of the head, and fevers. In these cases, applications to, and operations upon, the ear do no good. The only remedy is to remove, if possible, the diseased condition of the brain. 975. Imperfect hearing may be produced by the destruction of the membrana tympani, or removal of the bones of the ear, or the parts within the labyrinth. In these instances, medical treatment is of no avail, as the destroyed parts cannot be restored. 976. Hearing may be rendered defective by a diminution of the vibratory character of the membrana tympani. This may result from a thickening of this membrane, or from an accumulation of wax upon its outer surface. The increased thickness is usually the result of inflammation, either acute or chronic. The proper treatment is such as is efficient to remove inflammatory action. _Observations._ 1st. The introduction of heads of pins into the ear is a frequent cause of chronic inflammation of the membrana tympani. Hence this practice should never be adopted, and if acquired, should be abandoned. -=-=-=-=-=-=-=-=-=-=-=-= 973. On what does acute hearing depend? 974. State effects on the hearing in some conditions of the brain. How relieved? 975. Of the effect on hearing when the bones of the ear or the labyrinth are destroyed? Is medical treatment of any avail? 976. What conditions of the drum of the ear may impair hearing? How relieved? What is said of the introduction of pins to cleanse the ear? -=-=-=-=-=-=-=-=-=-=-=-= 2d. The accumulations of viscid wax may be softened by dropping some animal oil into the ear, and then removing it by ejecting warm soap suds a few hours subsequent to the use of the oil. This may be repeated for several successive days. 977. Hearing may be impaired by obstruction of the Eustachian tube. The closure of this canal diminishes the vibratory character of the air within the tympanum, in the same manner as closing the opening in the side of a drum. For the same reason, enlarged tonsils, inflammation and ulceration of the fauces and nasal passages during and subsequent to an attack of scarlet fever, and the inflammation attending the "sore throat" in colds, are common causes of this obstruction. 978. The treatment of such cases of defective hearing, is to have the tonsils, if enlarged, removed by a surgeon; for the inflammation and thickening of the parts remedial means should be applied, directed by a skilful physician. The nostrums for the cure of deafness are generally of an oleaginous character, and may be beneficial in cases of defective hearing caused by an accumulation of wax upon the drum of the ear, but in this respect they are no better than the ordinary animal oils. -=-=-=-=-=-=-=-=-=-=-=-= What is the remedy where there is an accumulation of wax? 977. What is the effect on hearing if the Eustachian tube is obstructed? 978. What is the treatment when deafness is caused by inflammation or ulceration the fauces? What is said of the nostrums used for deafness? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLVIII MEANS OF PRESERVING THE HEALTH.[23] [23] It is advised, that a thorough review of the hygiene of the preceding chapters be given from the suggestions contained in this. 979. Our bodies are constituted in harmony with certain laws, and every person should learn these, in order to regulate his actions and the performance of his duties, so that health may be unimpaired, and the power of enjoyment, activity, and usefulness continue while life lasts. 980. It is a law of the bones and the muscles, that they should either be used in some vocation, or called into action by some social play and active sport. 981. All admit that food is necessary to sustain life; and unless it be of a proper quality, taken in proper quantities, and at proper times, the functions of the digestive organs will be deranged, and disease produced. 982. Pure air is essential to the full enjoyment of health. The impure air of unventilated rooms may be breathed, and the effect be so gradual as not to arrest attention; yet it is a violation of the physical laws, and, sooner or later, we pay the penalty in disease and suffering. -=-=-=-=-=-=-=-=-=-=-=-= 979. Why is it incumbent on every person to learn the laws of health? 980. Give a law of the muscles. 981. In preserving the health, is it necessary to give attention to the food which is eaten? Why? 982. What beside food is essential to the full enjoyment of health? What is said of the impure air of unventilated rooms? 983. What should be observed in regard to sleep? -=-=-=-=-=-=-=-=-=-=-=-= 983. The body also requires sleep; and if it is not taken at the right time, or with regularity, we do not feel full refreshment from "tired nature's sweet restorer." Let youth be taught that "early to bed and early to rise" gives him health and its attendant blessings. The brain, like other organs of the body, should be called into action at proper times. 984. From the extent of the surface of the skin, and the close sympathy that exists between it and those organs whose office is, to remove the waste particles of matter from the body, it therefore becomes very important in the preservation of the health, that the functions of this membrane be properly maintained. 985. The function of the circulatory and secretory organs, together with the operations of absorption and nutrition, should be steadily maintained, as vitality and the generation of animal heat are intimately connected with these processes. In the proper performance of these functions, very much depends on the observance of the laws of the muscular, digestive respiratory, dermoid, and nervous apparatuses. REMOVAL OF DISEASE. 986. It is seldom that a physician is called in the first stages of disease. At this important period, the treatment adopted should be proper and judicious, or the sufferings of the patient are increased, and life, to a greater or less degree, is jeopardized. Hence the utility of knowing what _should be done_, and what _should not be done_, in order that the health may be rapidly regained. 987. In all instances of acute disease, it is proper to rest, not only the body, but the mind. To effect this, the patient should cease from physical exertion, and also withdraw his thoughts from study and business operations. This should be done, even if the person is but slightly indisposed. -=-=-=-=-=-=-=-=-=-=-=-= 984. Why should the functions of the skin be properly maintained? 985. Show the necessity of maintaining properly other functions of the system. 986. What is important in the first stages of disease? 987. What is proper in all instances of acute disease? How can it be effected? -=-=-=-=-=-=-=-=-=-=-=-= 988. Select a room for a sick person that is exposed to as little external noise as possible, as impressions made on the organ of hearing greatly influence the nervous system. Likewise select a spacious, well-ventilated apartment, that has no superfluous furniture. The practice of placing a sick person in a small, ill-arranged sleeping-room, when a more spacious room can be used, is poor economy, not to say unkind. 989. Care is necessary in regulating the light of a sick-room. While a strong light would produce an increased action of the vessels of the brain, a moderate light would be an appropriate stimulus to this organ. It is seldom or never necessary to exclude all light from the sick-chamber. 990. A sick person, whether a child or an adult, should not be disturbed by visitors, even if their calls are short. The excitement of meeting them is followed by a depression of the nervous system. The more dangerous and apparently nearer death the sick person is, the more rigorous should be the observance of this suggestion. Nor should the sick-room be opened to privileged classes; for the excitement caused by a visit from relations and the virtuous, will do as much injury to the sick, as that produced by strangers and the vicious. 991. The custom of visiting and conversing with sick friends during the intervals of daily labor, and particularly on _Sunday_, is a great evil. No person will thus intrude herself in the sick-chamber who cares more for the welfare of the suffering friend than for the gratification of a _sympathetic curiosity_. Inquiries can be made of the family respecting the sick, and complimentary or necessary messages can be communicated through the nurse. -=-=-=-=-=-=-=-=-=-=-=-= 988. What rooms should be selected for the sick? Why? 989. What is said in reference to the quantity of light admitted into a sick-room? 990. What effect have calls on the sick? 991. What is said of the custom of calling and conversing with the sick during the intervals of daily labor? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ While attending a Miss B., of N. H., sick of fever, I pronounced her better, withdrew medicine, directed a simple, low diet, and the exclusion of all visitors. In the evening I was sent for to attend her. There was a violent relapse into the disease, which continued to increase in severity until the fourth day, when death terminated her sufferings. I learned that, soon after I gave directions that no visitors be admitted into her room, several _particular_ friends were permitted to enter the chamber and talk with the sick girl. Their conversation produced a severe headache; and, to use the language of the patient, "it seemed as if their talk would kill me;" and _it did kill her_. 992. No _solid food_ should be taken in the first stages of disease, even if the affection is slight. The thirst can be allayed by drinking cold water, barley-water, and other preparations of an unstimulating character. It is wrong to tempt the appetite of a person who is indisposed. The cessation of a desire for food, is the warning of nature, that the system is in such a state that it cannot be digested. 993. When a patient is recovering from illness, the food should be simple, and in quantities not so great as to oppress the stomach. It should also be given with regularity. "Eat little and often," with no regard to regularity, is a pernicious practice. 994. When a physician attends a sick person, he should have the _special_ management of the food, particularly after the medicine has been withdrawn and the patient is convalescent. The prevailing idea that _every_ person may safely advise relative to food, or that the appetite of the convalescing person is a competent guide, is dangerous; and cannot be too much censured. -=-=-=-=-=-=-=-=-=-=-=-= Give an illustration. 992. What suggestion relative to food in the first stages of disease? How can the thirst be allayed? 993. When the patient is convalescent, how should the food be given? What is said of the practice of eating "little and often"? 994. Who should have the special management of food when medicine is withdrawn? What idea prevails in the community? -=-=-=-=-=-=-=-=-=-=-=-= _Illustration._ In 1832, I attended a Miss M., sick of fever. After an illness of a few days, the fever abated, and I directed a simple, unstimulating diet. Business called me from the town two days. During my absence, a sympathizing, officious matron called; found her weak, but improving; and told her she needed food to strengthen her; and that "it would now do her good." Accordingly, eggs and a piece of beefsteak were prepared, and given to the convalescent girl. She ate heartily, and the result was a relapse into a fever more violent than the first attack. 995. It is very important in disease that _the skin be kept clean_. A free action of the vessels of this part of the body exerts a great influence in removing disease from the internal organs, as well as keeping them in health. If the twenty or thirty ounces of waste, hurtful matter, that passes through the "pores" of the skin in twenty-four hours, are not removed by frequent bathing and dry rubbing, it deranges the action of the vessels that separate this waste matter from the blood, and thus increases the disease of the internal organs. _Illustration._ Mrs. M. R., of N., Mass., was afflicted with disease of the lungs and cough. This was accompanied with a dry, inactive condition of the skin. As medicine had no salutary effect in relieving her cough, she was induced by the advice of the clergyman of the parish to enter upon a systematic course of bathing twice every day. Soon the skin became soft, its proper functions were restored, the disease of the lungs yielded, and the cough disappeared. 996. Every sick person should breathe _pure air_. The purer the blood that courses through the body, the greater the energy of the system to remove disease. The confined vitiated air of the sick-chamber, not unfrequently prolongs disease; and in many instances, the affection is not only aggravated, but, even rendered fatal, by its injurious influences. -=-=-=-=-=-=-=-=-=-=-=-= Give an illustration of the evil effects attending such an idea. 995. Does the skin exert a great influence in removing disease from the internal organs, as well as in keeping them in health? Give an illustration 996. Why should every sick person, particularly, breathe pure air? -=-=-=-=-=-=-=-=-=-=-=-= _Illustrations._ 1st. In 1833, I was called, in consultation with another physician, to Mr. H., who was much debilitated, and delirious. For several successive days he had not slept. His room was kept very warm and close, for fear he would "take cold." The only change that I made in the treatment, was to open the door and window, at a distance from the bed. In a short time, the delirium ceased, and he fell into a quiet slumber. From this time he rapidly recovered, and the delirium was probably the result of breathing impure air. 2d. Formerly, every precaution was used to prevent persons sick of the small-pox from breathing fresh air. When Mrs. Ramsay had this disease in Charleston, S.C., her friends, supposing that life was extinct, caused her body to be removed from the house to an open shed. The pure air revived the vital spark. The result probably would have been different, had she been kept a few hours longer in the vitiated air. 997. The influence of habit should not be disregarded in the removal of disease. If food or drink is to be administered, however small in quantity or simple its quality, it should be given at or about the time when the ordinary meals were taken in health. 998. Again, the usual time when the patient was in the habit of retiring for sleep should be observed, and all preparation necessary for the sick-room during the night should be made previous to this hour. Efforts should also be made to evacuate the waste matter of the digestive and urinary organs at the period which habit has formed in health. This is not only a remedial agent in disease, but often precludes the necessity of laxative or drastic cathartics. -=-=-=-=-=-=-=-=-=-=-=-= Are not diseases prolonged, and even rendered fatal, from breathing the impure, vitiated air of the sick-chamber? Give illustration 1st. Give illustration 2d. 997. What is said respecting the influence of habit in removing disease? -=-=-=-=-=-=-=-=-=-=-=-= 999. MEDICINE is sometimes necessary to _assist_ the natural powers of the system to remove disease; but it is only an _assistant_. While emetics are occasionally useful in removing food and other articles from the stomach that would cause disease if suffered to remain, and cathartics are valuable, in some instances, to relieve the alimentary canal of irritating residuum, yet the frequent administration of either will cause serious disease. 1000. Although medicine is useful in some instances, yet, in a great proportion of the cases of disease, including fevers and inflammations of all kinds, attention to the laws of health will tend to relieve the system from disease; more certainly and speedily, and with less danger, than when medicines are administered. 1001. Thomas Jefferson, in writing to Dr. Wistar, of Philadelphia, said, "I would have the physician learn the limit of his art." I would say, Have the matrons, and those who are continually advising "herb teas," and other "cure-alls," for any complaint, labelled with some popular name, learn the limits of their duty, namely, attention to the laws of health. The rule of every family, and each individual, should be, to touch not, taste not of medicine of _any kind_, except when directed by a well-educated and honest physician, (sudden disease from accidents excepted.) -=-=-=-=-=-=-=-=-=-=-=-= 999. What is said of the use of medicine? 1000. Of its use in fevers and many other cases of disease? 1001. What remark by Thomas Jefferson to Dr. Wistar? What should matrons learn? What should be the rule of every person in regard to taking medicine? What exception? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLIX. DIRECTIONS FOR NURSES. 1002. The nurse requires knowledge and practice to enable her to discharge aright her duty to the patient, as much as the physician and surgeon do to perform what is incumbent on them. Woman, from her constitution and habits, is the natural nurse of the sick; and, in general, no small portion of her time is spent in ministering at the couch of disease and suffering. 1003. As the young and vigorous, as well as the aged and the infirm, are liable to be laid upon the bed of sickness, by an epidemic, or imprudent exposure, or by some accident, it is therefore necessary that the girl, as well as the matron, may know how she can render services in an efficient and proper manner. No _girl_ should consider her education complete who is not acquainted with the principles of the duties of a general nurse and a temporary watcher. 1004. It is to be regretted, that while we have medical schools and colleges to educate physicians, there is no institution to educate _nurses_ in their equally responsible station. In the absence of such institutions, the defect can be remedied, to some extent, by teaching every girl _hygiene_, or _the laws of health_. To make such knowledge more available and complete, attention is invited to the following suggestions relative to the practical duties of a nurse. -=-=-=-=-=-=-=-=-=-=-=-= 1002. Does the nurse require knowledge and practice in her employment, as well as the physician? Who is the natural nurse of the sick? 1003. What, then, is incumbent on every girl? 1004. Should there be schools to educate nurses, as well as physicians and surgeons? -=-=-=-=-=-=-=-=-=-=-=-= 1005. BATHING. The nurse, before commencing to bathe the patient, should provide herself with water, two towels, a sponge, a piece of soft flannel, and a sheet. The temperature of the room should also be observed. 1006. When the patient is feeble, use _tepid_ or warm water. Cold water should only be used when the system has vigor enough to produce reaction upon the skin. This is shown by the increased redness of the skin, and a feeling of warmth and comfort, after a proper amount of friction. Before using the sponge to bathe, a sheet, or fold of cloth, should be spread smoothly over the bed, and under the patient, to prevent the bed-linen on which the patient lies from becoming damp or wet. 1007. Apply the wet sponge to one part of the body at a time; as the arm, for instance. By doing so, the liability of contracting chills is diminished. Take a dry, soft towel, wipe the bathed part, and follow this by vigorous rubbing with a crash towel, or, what is better, a mitten made of this material; then use briskly a piece of soft flannel, to remove all moisture that may exist on the skin, and particularly between the fingers and the flections of the joints. In this manner bathe the entire body. 1008. The sick should be thoroughly bathed, at least twice in twenty-four hours. Particular attention should be given to the parts between the fingers and toes, and about the flections of the joints, as the accumulation of the excretions is most abundant on these parts. In bathing, these portions of the system are very generally neglected. The best time for bathing, is when the patient feels most vigorous, and freest from exhaustion. The practice of daubing the face and hands with a towel dipped in hot rum, camphor, and vinegar, does not remove the impurities, but causes the skin soon to feel dry, hard, and uncomfortable. -=-=-=-=-=-=-=-=-=-=-=-= 1005. What should a nurse provide herself with, before bathing a patient? 1006. When should cold water be used? 1007. How should the bathing then be performed, so that the patient may not contract a cold? 1008. How often should a sick person be bathed? What is said of daubing the face and hands merely with a wet cloth? -=-=-=-=-=-=-=-=-=-=-=-= 1009. FOOD. It is the duty of every woman to know how to make the simple preparations adapted to a low diet, in the most wholesome and the most palatable way. Water-gruel,[24] which is the simplest of all preparations, is frequently so ill-made as to cause the patient to loathe it. Always prepare the food for the sick, in the neatest and most careful manner. [24] Directions for making the simple preparations for the sick are found in almost every cook-book. 1010. When the physician enjoins abstinence from food, the nurse should strictly obey the injunction. She should be as particular to know the physician's directions about diet, as in knowing how and when to give the prescribed medicines, and obey them as implicitly. 1011. When a patient is convalescent, the desire for food is generally strong, and it often requires firmness and patience, together with great care, on the part of the nurse, that the food is prepared suitably, and given at proper times The physician should direct how frequently it should be taken. 1012. PURE AIR. It is the duty of the nurse to see that not only the room is well ventilated in the morning, but that fresh air is constantly admitted during the day. Great care must be taken, however, that the patient does not feel the current. 1013. Bed-linen, as well as that of the body, should be aired every day, and oftener changed in sickness than in health. All clothing, when changed, should be well dried, and warmed by a fire previous to its being put on the patient or the bed. -=-=-=-=-=-=-=-=-=-=-=-= 1009. Should every woman know how to make the simple preparations adapted to a low diet? 1010. Should the nurse strictly obey the injunctions of the physician relative to food? 1011. What period of a person's illness requires the most care in regard to the food? 1012. Give another duty of the nurse. 1013. What directions respecting the bed-linen of the patient? What is necessary when there is a change of clothing? -=-=-=-=-=-=-=-=-=-=-=-= 1014. TEMPERATURE. The warmth of the chamber should be carefully watched by the nurse. The feelings of the patient or nurse are not to be relied on as an index of the temperature of the room. There should be a well-adjusted thermometer in every sick-room. This should be frequently consulted by the nurse. 1015. The temperature of the sick-chamber should be _moderate_. If it is so cold as to cause a chill, the disease will be aggravated. If, on the other hand, it is too warm, the patient is enfeebled and rendered more susceptible to cold on leaving the sick-chamber. The Latin maxim, "_In medio tutissimus ibis_," (in medium there is most safety,) should be regarded in the rooms of the sick. 1016. QUIET. The room of the patient should be kept free from noise. The community should be guided by this rule, that no more persons remain in the room of the sick, than the welfare of the patient demands. It is the duty of the physician to direct when visitors can be admitted or excluded from the sick-room, and the nurse should see that these directions are enforced. 1017. The movements of the attendants should be gentle and noiseless. Shutting doors violently, creaking hinges, and all unnecessary noise, should be avoided. Most persons refrain from loud talking in the sick chamber, but are not equally careful to abstain from _whispering_, which is often more trying than a common tone. 1018. It is the duty of the nurse to ascertain the habits of the patient as respects the period for eating and sleep, when in health, that she may prepare the food and arrange the sick-room in accordance with the practice of the patient. If the person who is sick is ignorant of the necessity of the removal of the waste products from the system the nurse should invite attention to these functions at such periods as are in accordance with the previous habits of the patient. -=-=-=-=-=-=-=-=-=-=-=-= 1014. Why should there be a well-adjusted thermometer in every sick-chamber? 1015. What is said of the temperature of the sick-chamber? 1016. Why should the sick-room be kept quiet? 1017. What is said of noise in the sick-chamber? Of whispering? 1018. Should the habits of the patient be regarded in reference to the period for eating and sleep? -=-=-=-=-=-=-=-=-=-=-=-= 1019. The deportment and remarks of the nurse to the patient should be tranquil and encouraging. The illness of a friend, or persons who have recently died, should not be alluded to in the sick-room. No doubts or fears of the patient's recovery, either by a look or by a word, should be communicated by the nurse in the chamber of the sick. When such information is necessary to be communicated, it is the duty of the physician to impart it to the sick person. 1020. The nurse should not confine herself to the sick-room more than six hours at a time. She should eat her food regularly, sleep at regular periods, and take exercise daily in the open air. To do this, let her quietly leave the room when the patient is sleeping. A watcher, or temporary nurse, may supply her place. There is but little danger of contracting disease, if the nurse attends to the simple laws of health, and remains not more than six hours at a time in the sick-room. DIRECTIONS FOR WATCHERS. 1021. These necessary assistants, like the nurse, should have knowledge and practice. They should ever be cheerful, kind, firm, and attentive in the presence of the patient. 1022. A simple, nutritious supper should be eaten before entering the sick-room; and it is well, during the night, to take some plain food. -=-=-=-=-=-=-=-=-=-=-=-= 1019. What should be the deportment of the nurse toward the patient? Should doubts and fears of the patient's recovery be communicated in the sick-room? When necessary to impart such intelligence, on whom does it depend? 1020. How long should a nurse remain in the sick-chamber at a time? 1021. What qualifications are necessary in a watcher? 1022. What directions in regard to the food of the watcher? -=-=-=-=-=-=-=-=-=-=-=-= 1023. When watching in cold weather, a person should be warmly dressed, and furnished with an extra garment, as a cloak or shawl, because the system becomes exhausted toward morning, and less heat is generated in the body. 1024. Light-colored clothing should be worn by those who have care of the sick, in preference to dark-colored apparel; particularly if the disease is of a contagious character. Experiments have shown, that black and other dark colors will absorb more readily the subtile effluvia that emanate from sick persons, than white or light colors. 1025. Whatever may be wanted during the night, should be brought into the sick-chamber, or the adjoining room, before the family retires for sleep, in order that the slumbers of the patient be not disturbed by haste, or searching for needed articles. 1026. The same general directions should be observed by watchers, as are given to the nurse; nor should the watcher deem it necessary to make herself acceptable to the patient by exhausting conversation. 1027. It can hardly be expected that the farmer, who has been laboring hard in the field, or the mechanic, who has toiled during the day, is qualified to render all those little attentions that a sick person requires. Hence, would it not be more benevolent and economical to employ and _pay_ watchers, who are qualified by knowledge and _training_, to perform this duty in a faithful manner, while the kindness and sympathy of friends may be _practically_ manifested by assisting to defray the expenses of these qualified and useful assistants? -=-=-=-=-=-=-=-=-=-=-=-= 1023. When watching in cold weather, what precaution is necessary? 1024. What is said relative to the color of the clothing worn in the sick-room? 1025. What suggestions to watchers relative to the arrangement of the sick-chamber? 1026. What should watchers observe? 1027. What is said of employing those persons to watch who labor hard during the day? -=-=-=-=-=-=-=-=-=-=-=-= APPENDIX. POISONS AND THEIR ANTIDOTES 1028. POISONING, either from accident or design, is of such frequency and danger, that it is of the greatest importance that every person should know the proper mode of procedure in such cases, in order to render immediate assistance when within his power. 1029. Poisons are divided into two classes--_mineral_ (which include the acids) and _vegetable_. 1030. The first thing, usually, to be done, when it is ascertained that a poison has been swallowed, is to evacuate the stomach, unless vomiting takes place spontaneously. Emetics of the sulphate of zinc, (white vitriol,) or ipecacuanha, (ipecac,) or ground mustard seed, should be given. 1031. When vomiting has commenced, it should be aided by large and frequent draughts of the following drinks: flaxseed tea, gum-water, slippery-elm tea, barley water, sugar and water, or any thing of a mucilaginous or diluent character. MINERAL POISONS. 1032. AMMONIA.--The _water of ammonia_, if taken in an over-dose, and in an undiluted state, acts as a violent corrosive poison. 1033. The best and most effectual antidote is _vinegar_. It should be administered in water, without delay. It neutralizes the ammonia, and renders it inactive. Emetics should not be given. 1034. ANTIMONY.--The _wine of antimony_ and _tartar emetic_, if taken in over-doses, cause distressing vomiting. In addition to the diluent, mucilaginous drinks, give a tea-spoonful of the sirup of poppies, paregoric, or twenty drops of laudanum, every twenty minutes, until five or six doses have been taken, or the vomiting ceases. -=-=-=-=-=-=-=-=-=-=-=-= 1025. Is it useful to know the antidotes or remedies for poison? 1029. Into how many classes are poisons divided? 1030. What is the first thing to be done when it is ascertained that poison has been swallowed? 1031. What should be taken after the vomiting has commenced? 1032. What effect has an over-dose of ammonia? 1033. The antidote? Should an emetic be given for this poison? 1034. What effect has an over-dose of the wine of antimony or tartar emetic? -=-=-=-=-=-=-=-=-=-=-=-= 1035. The antidotes are _nutgalls_ and _oak bark_, which may be administered in infusion, or by steeping in water. 1036. ARSENIC.--When this has been taken, administer an emetic of ipecac, speedily, in mucilaginous teas, and use the stomach-pump as soon as possible. 1037. The antidote is the _hydrated peroxide of iron_. It should be kept constantly on hand at the apothecaries' shops. It may be given in any quantity, without injurious results. 1038. COPPER.--The most common cause of poisoning from this metal, is through the careless use of cooking utensils made of it, on which the _acetate of copper_ (verdigris) has been allowed to form. When this has been taken, immediately induce vomiting, give mucilaginous drinks, or the _white of eggs_, diffused in water. 1039. The antidote is the _carbonate of soda_, which should be administered without delay. 1040. LEAD.--The _acetate_ (sugar) _of lead_ is the preparation of this metal, which is liable to be taken accidentally, in poisonous doses. Induce immediate vomiting, by emetics of ground mustard seed, sulphate of zinc, and diluent drinks. 1041. The antidote is diluted _sulphuric acid_. When this acid is not to be obtained, either the sulphate of magnesia, (epsom salts,) or the sulphate of soda, (glauber's salts,) will answer every purpose. 1042. MERCURY.--The preparation of this mineral by which poisoning is commonly produced, is _corrosive sublimate_. The mode of treatment to be pursued when this poison has been swallowed, is as follows: The _whites of a dozen eggs_ should be beaten in two quarts of cold water, and a tumbler-full given every two minutes, to induce vomiting. When the whites of eggs are not to be obtained, soap and water should be mixed with wheat flour, and given in copious draughts, and the stomach-pump introduced as soon as possible. Emetics or irritating substances should not be given. 1043. NITRE--_Saltpetre._--This, in over-doses, produces violent poisonous symptoms. Vomiting should be immediately induced by large doses of mucilaginous, diluent drinks; but emetics which irritate the stomach should not be given. -=-=-=-=-=-=-=-=-=-=-=-= 1035. What is the antidote? 1036. What should immediately be done when arsenic is swallowed? 1037. What is the antidote? Can any quantity of this preparation of iron be given without injurious results? 1038. What should be given when verdigris has been taken into the stomach? 1039. What is the antidote? 1040. What should immediately be given when sugar of lead is taken? 1041. What is the antidote? 1042. Give the treatment when corrosive sublimate has been swallowed. 1043. What effect has an over-dose of saltpetre? What treatment should be adopted? -=-=-=-=-=-=-=-=-=-=-=-= 1044. ZINC.--Poisoning is sometimes caused by the _sulphate of zinc_, (white vitriol.) When this takes place, vomiting should be induced, and aided by large draughts of mucilaginous and diluent drinks. Use the stomach-pump as soon as possible. 1045. The antidote is the _carbonate_, or _super-carbonate of soda_. 1046. NITRIC, (aqua fortis,) MURIATIC, (MARINE ACID,) OR SULPHURIC (OIL OF VITRIOL,) ACIDS, may be taken by accident, and produce poisonous effects. 1047. The antidote is _calcined magnesia_, which should be freely administered, to neutralize the acid and induce vomiting. When magnesia cannot be obtained, the _carbonate of potash_ (salæratus) may be given. _Chalk_, powdered and given in solution, or strong _soap suds_, will answer a good purpose, when the other articles are not at hand. It is of very great importance that something be given speedily, to neutralize the acid. One of the substances before mentioned should be taken freely, in diluent and mucilaginous drinks, as gum-water, milk, flaxseed, or slippery-elm tea. Emetics ought to be avoided. 1048. OXALIC ACID.--This acid resembles the sulphate of magnesia, (epsom salts,) which renders it liable to be taken, by mistake, in poisonous doses. Many accidents have occurred from this circumstance. They can easily be distinguished by tasting a small quantity. _Epsom salts_, when applied to the tongue, have a very bitter taste, while _oxalic acid_ is intensely sour. 1049. The antidote is _magnesia_, between which and the acid a chemical action takes place, producing the oxalate of magnesia, which is inert. When magnesia is not at hand, _chalk_, _lime_, or _carbonate of potash_, (salæratus,) will answer as a substitute. Give the antidote in some of the mucilaginous drinks before mentioned. No time should be lost in introducing the stomach-pump as soon as a surgeon can be obtained. 1050. LEY.--The ley obtained by the leaching of ashes may be taken by a child accidentally. The antidote is vinegar, or oil of any kind. The vinegar neutralizes the alkali by uniting with it, forming the acetate of potash. The oil unites with the alkali, and forms soap, which is less caustic than the ley. Give, at the same time, large draughts of mucilaginous drinks, as flaxseed tea, &c. -=-=-=-=-=-=-=-=-=-=-=-= 1044. What is the antidote for white vitriol? 1047. What is the antidote for aqua fortis and oil of vitriol? Should emetics be avoided? 1048. How can oxalic acid be distinguished from epsom salts? 1049. What is the antidote for an over-dose of oxalic acid? When magnesia cannot be obtained, what will answer as a substitute? 1050. What is the antidote when ley is swallowed? -=-=-=-=-=-=-=-=-=-=-=-= VEGETABLE POISONS. 1051. The vegetable poisons are quite as numerous, and many of them equally as virulent, as any in the mineral kingdom. We shall describe the most common, and which, therefore, are most liable to be taken. 1052. OPIUM.--This is the article most frequently resorted to by those wishing to commit suicide, and, being used as a common medicine, is easily obtained. From this cause, also, mistakes are very liable to be made, and accidents result from it. Two of its preparations, _laudanum_ and _paregoric_, are frequently mistaken for each other; the former being given when the latter is intended. 1053. _Morphia_, in solution, or _morphine_, as it is more commonly called by the public, is a preparation of the drug under consideration, with which many cases of poisoning are produced. It is the active narcotic principle of the opium; and one grain is equal to six of this drug in its usual form. 1054. When an over-dose of opium, or any of its preparations, has been swallowed, the stomach should be evacuated as speedily as possible. To effect this, a teaspoonful of ground mustard seed, or as much tartar emetic as can be held on a five cent piece, or as much _ipecacuanha_ as can be held on a twenty-five cent piece, should be mixed in a tumbler of warm water, and one half given at once, and the remainder in twenty minutes, if the first has not, in the mean time, operated. In the interval, copious draughts of warm water, or warm sugar and water, should be drank. 1055. The use of the stomach-pump, in these cases, is of the greatest importance, and should be resorted to without delay. After most of the poison has been evacuated from the stomach, a strong infusion of _coffee_ ought to be given; or some one of the vegetable acids, such as _vinegar_, or _lemon-juice_, should be administered. 1056. The patient should be kept in motion, and salutary effects will often be produced by dashing a bucket of cold water on the head. _Artificial respiration_ ought to be established, and kept up for some time. If the extremities are cold, apply warmth and friction to them. After the poison has been evacuated from the stomach, stimulants, as warm wine and water, or warm brandy and water, should be given, to keep up and sustain vital action. 1057. STRAMONIUM--_Thorn-Apple._--This is one of the most active narcotic poisons, and, when taken in over-doses, has, in numerous instances, caused death. -=-=-=-=-=-=-=-=-=-=-=-= 1051. Are vegetable poisons as numerous and as virulent in their effects as mineral? 1052. What is said of opium and its preparations? 1054, 1055, 1056. What treatment should be adopted when an over-dose of opium or any of its preparations is taken? 1057. What is said of stramonium? -=-=-=-=-=-=-=-=-=-=-=-= 1058. HYOSCIAMUS--_Henbane._--This article, which is used as a medicine, if taken in improper doses, acts as a virulent irritating and narcotic poison. 1059. The treatment for the two above-mentioned articles is similar to that of poisoning from over-doses of opium. 1060. CONIUM--_Hemlock._--Hemlock, improperly called, by many, _cicuta_, when taken in an over-dose, acts as a narcotic poison. It was by this narcotic that the Athenians used to destroy the lives of individuals condemned to death by their laws. Socrates is said to have been put to death by this poison. When swallowed in over-doses, the treatment is similar to that of opium, stramonium, and henbane, when over-doses are taken. 1061. BELLADONNA--_Deadly Nightshade._--CAMPHOR. ACONITE--_Monkshood_, _Wolfsbane._ BRYONIA--_Bryony._ DIGITALIS--_Foxglove._ DULCAMARA--_Bittersweet._ GAMBOGE. LOBELIA--_Indian Tobacco._ SANGUINARIA--_Bloodroot._ OIL OF SAVIN. SPIGELIA--_Pinkroot._ STRYCHNINE--_Nux vomica._ TOBACCO.--All of these, when taken in over-doses, are poisons of greater or less activity. The treatment of poisoning, by the use of any of these articles, is similar to that pursued in over-doses of opium. (See OPIUM, page 442.) 1062. In _all_ cases of poisoning, call a physician as soon as possible. -=-=-=-=-=-=-=-=-=-=-=-= 1058. Of henbane? 1059. What should be the treatment when an over-dose of stramonium or henbane is taken? 1060. What name is sometimes improperly given to _conium_, or hemlock? How was this narcotic poison used by the Athenians? How are the effects of an over-dose counteracted? 1061. What is the treatment when an over-dose of deadly nightshade, monkshood, foxglove, bittersweet, gamboge, lobelia, bloodroot, tobacco, &c., is taken? 1062. Should a physician be called in all cases when poison is swallowed? -=-=-=-=-=-=-=-=-=-=-=-= A. The essential parts of every secretory apparatus are a simple membrane, apparently textureless, named the _primary_, or _basement membrane_, certain cells and blood-vessels. The serous and mucous membrane are examples. B. The division and description of the different membranes and tissues are not well defined and settled by anatomical writers. This is not a material defect, as a clear description of the different parts of the system can be given by adopting the arrangement of almost any writer. C. FAT is one of the non-nitrogenous substances. It forms the essential part of the adipose tissue. Chemical analysis shows that all fatty substances are compounds of carbon, hydrogen, and oxygen. They are lighter than water, generally fluid at the natural temperature of the body, and burn with a bright flame, forming water and carbonic acid. CASEINE is abundantly found in milk. When dried, it constitutes cheese. Alcohol, acids, and the stomach of any of the mammalia coagulate it; and it is also soluble in water. It is found in the blood, bile, saliva, and the lens of the eye. CHONDRINE is a variety of gelatin. It is obtained from cartilage. It is soluble in warm water, but solidifies on cooling. LACTIC ACID is common to all the solids and fluids of the system. It is found united with potash, soda, lime, or magnesia. D. The word _duodenum_ is derived from the Latin, signifying "twelve," since the intestine, of which this is the name, is usually about twelve fingers' breadth in length. The _jejunum_ is also from the Latin _jejunum_, empty, since it is usually found in that condition after death, as the food seems to pass rapidly through this part of the intestine. The term _ileum_ is from the Greek, signifying "to twist," since it always appears in a contorted condition. The name _cæcum_ is derived from the fact of its being a blind or short sack, perforated by the extremity of the ileum. The name of the next division of the intestine--_colon_--is from the Greek, "to prohibit," as the contents of the alimentary canal pass slowly through this portion. The _rectum_ is named from the straight direction that it assumes in the latter part of its course. E. The food is forced through the alimentary canal by contractions of its muscular coat, produced by the nervous filaments of the sympathetic system, not being at all dependent on the cerebro-spinal centre. This is called the peristaltic, or vermicular motion. The great length of intestine in all animals, and especially in the herbivorous ones, is owing to the necessity of exposing the food to a large number of the lacteals, that the nourishment may all be taken from it. F. The different processes through which the food passes before assimilation are of considerable interest. The mastication and mixture of the saliva with the food are purely of a mechanical nature. When any solid or fluid substance is placed upon the tongue, or in contact with the inner surface of the cheeks, by an involuntary act, the salivary glands are stimulated to activity, and commence pouring the saliva into the mouth through the salivary ducts. As soon as mastication commences, the contraction of the masseter and other muscles employed in mastication stimulates the salivary glands to increased action, and a still greater quantity of saliva is secreted and forced upon the food, which is constantly being ground to a finer condition, until it is sufficiently reduced for deglutition. Whether the salivary fluid acts any other part than simply that of a demulcent to assist the gastric juice in still further dissolving the food, is yet a matter of some doubt, although it is found that no other liquid will equally well subserve the process of digestion and promote health. After the food is in the condition ready to be swallowed, by an apparently involuntary motion, it is placed upon the back of the tongue, which carries it backwards to the top of the pharynx, where the constrictions of the pharynx, aided by the muscles of the tongue and floor of the mouth, with a sudden and violent movement thrust it beyond the epiglottis, in order to allow the least necessary time to the closure of the glottis, after which, by the compression of the oesophagus, it is forced into the stomach. Here it is that the true business of digestion commences. For as soon as any substance except water enters the stomach, this organ, with involuntary movements, that seem almost like instinct, commences the secretion of the gastric juice, and by long-continued contractions of its muscular coat, succeeds in effecting a most perfect mixture of the food with this juice, by which the contents of the stomach are reduced to the softest pulp. The gastric juice, in its pure state, is a colorless, transparent fluid; "inodorous, a little saltish, and perceptibly acid. It possesses the property of coagulating albumen, and separating the whey of milk from its curd, and afterwards completely dissolving the curd. Its taste, when applied to the tongue, is similar to that of mucilaginous water, slightly acidulated with muriatic acid." The organs of its secretion are an immense number of tubes or glands, of a diameter varying from one five hundredth to one three hundredth of an inch, situated in the mucous coat of the stomach, and receiving their blood from the gastric arteries. A chemical analysis shows it to consist of water, mucilage, and the several free acids--muriatic, acetic, lactic, and butyric, together with a peculiar organic matter called _pepsin_, which acts after the manner of ferments between the temperature of 50° and 104° F. The true process of digestion is probably owing to the action of pepsin and the acids, especially if the presence of the chloro-hydric or muriatic be admitted; since we know, by experiments out of the body, that chlorine, one of its elements, is a powerful solvent of all organic substances. The antiseptic properties of the gastric juice, as discovered by experiments made on Alexis St. Martin, doubtless have much influence on digestion, although their true uses are probably not yet known. As soon as the food is reduced to a state of fluidity, the pyloric orifice of the stomach is unclosed, and it is thrust onwards through the alimentary canal, receiving in the duodenum the secretions of the liver and pancreas, after which it yields to the lacteals its nutrient portion, and the residuum is expelled from the body. There have been many hypotheses in regard to the nature of the digestive process. Some have supposed that digestion is a mere mechanical process, produced by the motion of the walls of the stomach; while others, in later times, have considered it as under the influence of a spirit separate from the individual, who took up his residence in the stomach and regulated the whole affair; while others still would make it out to be a chemical operation, and thus constitute the stomach a sort of laboratory. But to all these ridiculous hypotheses Sir John Hunter has applied the following playful language: "Some will have it that the stomach is a mill; others that it is a fermenting vat; and others that it is a stewpan; but in my view of the matter, it is neither a mill, a fermenting vat, nor a stewpan, but a stomach, _a stomach_!" At the present day this process is regarded as a complex, and not a simple operation. It seems to be a process in which the mechanical, chemical, and vital agencies must all act in harmony and order; for if one of these be withdrawn, the function cannot be sustained for any considerable length of time; and of the chemical and mechanical parts of the process, since the former is much more important, and, as a matter of course, the vital powers are indispensable, therefore digestion may be considered as a chemical operation, directly dependent on the laws of vitality, or of life; since the proper consistency of the food depends, in a great measure, upon the character of the solvents, while the secretion of these fluids, their proper amount, together with the peculiar instinct--as it almost seems to be--necessary to direct the stomach in its many functions, are exclusively and entirely dependent on the laws and conditions of life. G. As food is necessary to supply the waste and promote the growth of the body, it follows that that will be the best adapted to the system which contains the same chemical elements of which the body is composed; viz., oxygen, hydrogen, carbon, and nitrogen. These elements are found in greater or less quantity in all animal food, and in many vegetable products. Hence, that article of food which contains all these elements in a proper proportion will tend much more to the growth and strength of the body than those kinds which are deficient in one or more of them. Much experience on this point, and scientific research, seem to show that a reasonable amount of animal food in health tends to give greater strength of muscle, and a more general sense of fulness, than in ordinary cases a vegetable diet is able to do, owing to the presence of nitrogen in animal tissues. Yet there are examples of the healthiest and strongest men, who live years without a morsel of animal food; and the fact can only be accounted for, by supposing that the system has the power to make the most economical use of the little nitrogen offered to it in the food; or else that it has by some means the power to abstract it from the atmosphere, and transform it to the living animal substance. H. The proximate principles, which are the most important in nourishing the body, are albumen and fibrin. These constitute the greater part of all the softer animal tissues, and are also found in certain classes of vegetables, such as peas, beans, lentils, and many seeds. Hence, in many cases, a vegetable diet, especially if embracing any of those articles, would be sufficient to sustain life, even if no animal food should be eaten. But no animal can exist for a long time if permitted only to eat substances destitute of nitrogen, as in the case of a dog fed entirely on sugar, which lived but thirty days. And owing to this fact, Baron Liebig proposes to call substances used for food, containing nitrogen, "elements of nutrition," and those containing an excess of carbon, "elements of respiration;" since, according to his view, the food is necessary to support the growth of the body by replacing the effete and worn-out particles with new matter, and also to keep up the supply of fuel, in order to promote a sufficient degree of heat in the system. Accordingly, under the first division would be included all lean meats and vegetables, such as peas, &c.; while the fat of animals, vegetable oils, sugars, tubers, (as the potato,) and all other substances containing starch, would be included under the latter division. I. This definition of exhalants is from the theory of Haller and others. It is now believed that the fluids exude through the thin coats of the blood vessels. This process is called _exosmose_, and is the _exhalation_ of old physiologists. J. It is a well-established fact, in animal and vegetable physiology, that membranes possess the property of allowing fluids and gases to pass through them in either direction, and also to permit two fluids to pass in opposite directions at the same time. This property is designated _endosmose_ when a fluid passes from without a body inward; and _exosmose_ when the reverse takes place. The first is called _imbibition_. One of the most striking instances of this, in the human system, is shown in the lungs, where carbonic acid and water pass out through the mucous membrane of the bronchial tubes and air-cells; and the oxygen of the air enters the blood through the same membrane. By this process of imbibition, the oxygenation of the blood is much more readily and faithfully accomplished; inasmuch, as by the immense number of bronchial tubes and air-cells a larger quantity of blood is exposed to a greater portion of air, than if the blood were directly laid open to the atmosphere in a mass, or the air were immediately transmitted through it. Since the function of respiration is to free the system of superfluous carbon and hydrogen, by union with the oxygen of the air, it follows that the greater the amount of the products to be expelled, the larger the quantity of oxygen will be required to effect this purpose, as we find to be the case with those who consume large quantities of food. The quantity of oxygen daily consumed through the lungs by an adult is about 32.5 oz., and the carbon in the food 13.9 oz. But in order to convert this whole amount of carbon into carbonic acid, which passes off through the lungs and skin, 37 oz. of oxygen are required; the remaining 4.5 oz. being absorbed by the skin. If the supply of food remain the same, while the amount of oxygen in the inspired air is diminished, the superfluous carbon will induce disease in the system, as is the case of those persons who are limited in their supply of air of a proper quality or quantity, and, consequently, have less appetite for food than those who are abundantly supplied with air of the proper standard of health; and in children, who proportionally consume more food than adults, and who are more active, thereby causing a more rapid circulation of blood, and, consequently, the removal of more superfluous particles of matter. In children we notice the need of air, by their disposition to be much in the open air, and often inspiring more deeply than is common in older persons. Also, if the carbon of the food does not have a requisite supply of oxygen from the air, or other sources, the body becomes emaciated, although nourishing food may be used. And on the other hand, if there be a diminished supply of food, but an abundance of atmospheric air, leanness and emaciation are sure to follow; owing to the fact that if the oxygen has no waste carbon from the body to unite with, it combines with the fat, and some other soft portions of the body, which the Author of nature seems to have provided for this very purpose; as is seen in the case of hibernating animals, who enter their places of winter abode sleek and fat, but crawl out in the spring not merely deprived of their fatty matter, but also with great diminution of all the softer parts, which have given up their share of carbon to supply animal heat. One important cause of emaciation in febrile diseases is the greater rapidity of the pulse and respiration, which consume more carbon than is afforded by the scanty supply of food that is taken, although profuse perspiration, which almost always occurs in some stages of fevers, greatly diminishes the full state of the body. K. The theory of Baron Liebig concerning the change which the blood experiences in color, in its passage through the lungs, meets with the approbation of many physiologists, although there are some important difficulties in the way of fully receiving it. A chemical analysis of the blood shows it to be composed of albumen and fibrin, together with some other substances, in small proportions, and always perceptible traces of iron. He attributes the change in color to the iron, as this substance enters into combination with carbon and oxygen. For, as the blood passes through the trunks of the larger vessels and capillaries, it receives the carbon from the tissues which are continually transformed, and taking up the oxygen from the arterialized blood, forms carbonic acid, which unites with the iron, forming proto-carbonate of iron. This being of a gray color, he supposes it to be that which, with the other impurities of the blood, gives the venous blood the dark blue color. Then, as the blood comes in contact with the oxygen, as it is returned and exposed to this element in the lungs, the carbonic acid leaves the iron, which has a stronger affinity for oxygen than for carbonic acid, and forms the scarlet red peroxide of iron, that gives the characteristic color to the arterial blood. After this, as the blood is sent out through the smaller arteries and capillaries, it again gathers carbon and other impurities from the system, and becomes the dark, venous blood, thus completing the whole change of color in the circulation. L. As already mentioned, different articles of food have been divided into the azotized and non-azotized, or those which contain nitrogen as one of their constituents, and those which are nearly destitute of it. Of these, according to Liebig, the azotized portions are simply to supply the waste that is continually going on in the body, and promote its growth in the early stages of existence, or, in other words, the nutrient portion; while the sugar, starch, &c., are mainly of use in the respiratory organs. The correctness of this view may be understood from the fact, that the inhabitants in the colder regions of the earth consume a much larger quantity of oil and fat than the residents of hotter climates; and also those dwelling in the temperate zones can eat with greater impunity a larger quantity of fat meats in the winter than in the summer, there being then so much more demand for animal heat than in the summer. M. The suggestion of using the bellows in asphyxia, is from the directions of that distinguished and veteran surgeon, Valentine Mott, of New York city. The directions in the first part of the paragraph are the most practical, and best adapted to the wants of the community. GLOSSARY AB-DUC´TOR. [L. _abduco_ to lead away.] A muscle which moves certain parts, by separating them from the axis of the body. AB-DO´MEN. [L. _abdo_, to hide.] That part of the body which lies between the thorax and the bottom of the pelvis. AB-DOM´IN-IS. Pertaining to the abdomen. A-CE-TAB´U-LUM. [L. _acetum_, vinegar.] The socket for the head of the thigh-bone; an ancient vessel for holding vinegar. A-CE´TIC. [L. _acetum_, vinegar.] Relating to acetic acid. This is always composed of oxygen, hydrogen, and carbon, in the same proportion. A-CHIL´LIS. A term applied to the tendon of two large muscles of the leg. A-CRO´MI-ON. [Gr. +akros+, _akros_, highest, and +ômos+, _omos_, shoulder.] A process of the scapula that joins to the clavicle. AD-DUC´TOR. [L. _adduco_, to lead to.] A muscle which draws one part of the body toward another. AL-BU-GIN´E-A. [L. _albus_, white.] A term applied to white textures. AL-BU´MEN. [L. _albus_, white.] An animal substance of the same nature as the white of an egg. A-LU´MIN-UM. [L.] The name given to the metallic base of alumina. AL´VE-O-LAR. [L. _alveolus_, a socket] Pertaining to the sockets of the teeth. AM-MO´NI-A. An alkali. It is composed of three equivalents of hydrogen and one of nitrogen. A-NAS´TO-MOSE. [Gr. +ana+, _ana_, through, and +stoma+, _stoma_, mouth.] The communication of arteries and veins with each other. AN-A-TOM´I-CAL. Relating to the parts of the body, when dissected or separated. A-NAT´O-MY. [Greek +ana+, _ana_, through, and +tomê+, _tomê_ a cutting.] The description of the structure of animals. The word _anatomy_ properly signifies dissection. AN´GU-LI. [L. _angulus_, a corner.] A term applied to certain muscles on account of their form. AN-I-MAL´CU-L�. [L. _animalcula_, a little animal.] Animals that are only perceptible by means of a microscope. AN´NU-LAR. [L. _annulus_, a ring.] Having the form of a ring. AN-TI´CUS. [L.] A term applied to certain muscles. A-ORT´A. [Gr. +aortê+, _aortê_; from +aêr+, _aêr_, air, and +têreô+, _têreo_, to keep.] The great artery that arises from the left ventricle of the heart. AP-O-NEU-RO´SIS. [Gr. +apo+, _apo_, from, and +neuron+, _neuron_, a nerve.] The membranous expansions of muscles and tendons. The ancients called every white tendon _neuron_, a nerve. AP-PA-RA´TUS. [L. _apparo_, to prepare.] An assemblage of organs designed to produce certain results. AP-PEND´IX. [L., an addition.] Something appended or added. A´QUE-OUS. [L. _aqua_, water.] Partaking of the nature of water. A-RACH´NOID. [Gr. +arachnê+, _arachnê_, a spider, and +eidos+, _eîdos_, form.] Resembling a spider's web. A thin membrane that covers the brain. AR´BOR. [L.] A tree. _Arbor vitæ._ The tree of life. A term applied to a part of the cerebellum. AR´TE-RY. [Gr. +aêr+, _aêr_, air, and +têreô+, _têreo_, to keep; because the ancients thought that the arteries contained only air.] A tube through which blood flows from the heart. A-RYT-E´NOID. [Gr. +arytaina+, _arutaina_, a ewer, and +eidos+, _eîdos_, form.] The name of a cartilage of the larynx. AS-CEND´ENS. [L.] Ascending; rising. AS-PHYX´I-A. [Gr. +a+, _a_, not, and +sphyxis+, _sphyxis_, pulse.] Originally, want of pulse; now used for suspended respiration, or apparent death. AS-TRAG´A-LUS. [Gr.] The name of a bone of the foot. One of the tarsal bones. AUD-I´TION. [L. _audio_, to hear.] Hearing. AUD-IT-O´RI-US. [L.] Pertaining to the organ of hearing. AU´RI-CLE. [L. _auricula_, the external ear; from _auris_, the ear.] A cavity of the heart. AU-RIC´U-LAR. [L. _auricula_.] Pertaining to the auricle. AX-IL´LA. [L.] The armpit. AX´IL-LA-RY. Belonging or relating to the armpit. A-ZOTE´. [Gr. +a+, _a_, not, and +zôê+, _zoê_, life.] Nitrogen. One of the constituent elements of the atmosphere. So named because it will not sustain life. BEN-ZO´IC. _Benzoic acid._ A peculiar vegetable acid, obtained from benzoin and some other balsams. BI´CEPS. [L. _bis_, twice, and _caput_, a head.] A name applied to muscles with two heads at one extremity. BI-CUS´PIDS. [L. _bis_ and _cuspis_, a point.] Teeth that have two points upon their crown. BILE. [L. _bilis_.] A yellow, viscid fluid secreted by the liver. BI-PEN´NI-FORM. [L. _bis_ and _penna_, a feather.] _Bipenniform muscle._ Having fibres on each side of a common tendon. BRACH´I-AL. [L. _brachium_.] Belonging to the arm. BRE´VIS. [L.] _Brevis_, short; _brevior_, shorter. BRONCH´I-A, -�. [L.] A division of the trachea that passes to the lungs. BRONCH´I-AL. Relating to the bronchia. BRONCH-I´TIS. [L.] An inflammation of the bronchia. BUC-CI-NA´TOR. [L. _buccinum_, a trumpet.] The name of a muscle of the cheek, so named because used in blowing wind instruments. BUR´S� MU-CO´SA. [L. _bursa_, a purse, and _mucosa_, viscous.] Small sacs, containing a viscid fluid, situated about the joints, under tendons. C�´CUM. [L.] Blind; the name given to the commencement of the colon. CALX, CAL´CIS. [L.] The heel-bone. CAL´CI-UM. [L.] The metallic basis of lime. CAP´IL-LA-RY. [L. _capillus_, a hair.] Resembling a hair; small. CAP´SU-LAR. Pertaining to a capsule. CAP´SULE. [L. _capsula_, a little chest.] A membranous bag, enclosing a part. CA´PUT. [L.] The head. _Caput coli._ The head of the colon. CAR´BON. [L. _carbo_, a coal.] Pure charcoal. An elementary combustible substance. CAR-BON´IC. Pertaining to carbon. CAR´DI-AC. [Gr. +kardia+, _kardia_, heart.] Relating to the heart, or upper orifice of the stomach. CAR´NE-A, -�. [L. _caro_, _carnis_, flesh.] Fleshy. CA-ROT´ID. [Gr. +karos+, _karos_, lethargy.] The great arteries of the neck that convey blood to the heart. The ancients supposed drowsiness to be seated in these arteries. CAR´PAL. [L. _carpus_, the wrist.] Relating to the wrist. CAR´PUS, -I. [L.] The wrist. CAR´TI-LAGE. [L. _cartilago_.] Gristle. A smooth, elastic substance, softer than bone. CAR-TI-LAG´IN-OUS. Pertaining to cartilage. CAU-CA´SIAN. One of the races of men. CA´VA. [L.] Hollow. _Vena cava._ A name given to the two great veins of the body. CEL´LU-LAR. [L. _cellula_, a little cell.] Composed of cells. CER-E-BEL´LUM. [L.] The hinder and lower part of the brain, or the little brain. CER´E-BRAL. Pertaining to the brain. CER´E-BRUM. [L.] The front and large part of the brain. The term is sometimes applied to the whole contents of the cranium. CER´E-BRO-SPI´NAL. Relating to the brain and spine. CER´VIX. [L.] The neck. CER´VI-CAL. Relating to the neck. CHEST. [Sax.] The thorax; the trunk of the body from the neck to the abdomen. CHLO´RINE. [Gr. +chloros+, _chloros_, green.] _Chlorine gas_, so named from its color. CHOR´DA, -�. [L.] A cord. An assemblage of fibres. CHO´ROID. [Gr. +chorion+, _chorion_.] A term applied to several parts of the body that resemble the skin. CHYLE. [Gr. +chulos+, _chulos_, juice.] A nutritive fluid, of a whitish appearance, which is extracted from food by the action of the digestive organs. CHYL-I-FI-CA´TION. [_chyle_ and L. _facio_, to make.] The process by which chyle is formed. CHYME. [Gr. +chumos+, _chumos_, juice.] A kind of grayish pulp formed from the food in the stomach. CHYM-I-FI-CA´TION. [_chyme_ and L. _facio_, to make.] The process by which chyme is formed. CIL´IA-RY. [L. _cilia_, eyelashes.] Belonging to the eyelids. CIN-E-RI´TIOUS. [L. _cinis_, ashes.] Having the color of ashes. CLAV´I-CLE. [L. _clavicula_, from _clavis_, a key.] The collar-bone; so called from its resemblance in shape to an ancient key. CLEI´DO. A term applied to some muscles that are attached to the clavicle. CO-AG´U-LUM. [L.] A coagulated mass, a clot of blood. COC´CYX. [Gr.] An assemblage of bones joined to the sacrum. COCH´LE-A. [Gr. +kochlô+, _kochlo_, to twist; or L. _cochlea_, a screw.] A cavity of the ear resembling in form a snail shell. CO´LON. [Gr.] A portion of the large intestine. CO-LUM´NA, -�.[L.] A column or pillar. COM-MU´NIS. [L.] A name applied to certain muscles. COM-PLEX´US. [L. _complector_, to embrace.] The name of a muscle that embraces many attachments. COM-PRESS´OR. [L. _con_, together, and _premo_, _pressus_, to press.] A term applied to some muscles, that compress the parts to which they are attached. CON´DYLE. [Gr. +kondulos+, _kondulos_, a knuckle, a protuberance.] A prominence on the end of a bone. CON-JUNC-TI´VA. [L. _con_, together, and _jungo_, to join.] The membrane that covers the anterior part of the globe of the eye. COP´PER. A metal of a pale, red color, tinged with yellow. COR-A´COID. [Gr. +korax+, _korax_, a crow, and +eidos+, _eîdos_, form.] A process of the scapula shaped like the beak of a crow. CO´RI-ON. [Gr. +chorion+, _chorion_, skin.] The true skin. CORN´E-A. [L. _cornu_, a horn.] The transparent membrane in the fore part of the eye. COS´TA. [L. _costa_, a coast, side, or rib.] A rib. CRIB´RI-FORM. [L. _cribrum_, a sieve, and _forma_, form.] A plate of the ethmoid bone, through which the olfactory nerve passes to the nose. CRI´COID. [Gr. +krikos+, _krikos_, a ring, and +eidos+, _eîdos_, form.] A name given to a cartilage of the larynx, from its form. CRYS´TAL-LINE. [L. _crystallinus_, consisting of crystal.] _Crystalline lens._ One of the humors of the eye. It is convex, white, firm, and transparent. CU´BI-TUS, -I. [L. _cubitus_, the elbow.] One of the bones of the forearm, also called the _ulna_. CU´BOID. [Gr. +kubos+, _kubos_, a cube, and +eidos+, _eîdos_, form.] Having nearly the form of a cube. CU-NE´I-FORM. [L. _cuneus_, a wedge.] The name of bones in the wrist and foot. CUS´PID. [L. _cuspis_, a point.] Having one point. CU-TA´NE-OUS. [L. _cutis_, skin.] Belonging to the skin. CU´TI-CLE. [L. _cutis_.] The external layer of the skin. CU´TIS VE´RA. [L. _cutis_, and _vera_, true.] The internal layer of the skin; the true skin. DEL´TOID. [Gr. +delta+, _delta_, the Greek letter +Delta+, and +eidos+, _eîdos_, form.] The name of a muscle, that resembles in form the Greek letter +Delta+. DENS. [L.] A tooth. DENT´AL. [L. _dens_, tooth.] Pertaining to the teeth. DE-PRESS´OR. [L.] The name of a muscle that draws down the part to which it is attached. DERM´OID. [Gr. +derma+, _derma_, the skin, and +eidos+, _eîdos_, form.] Resembling skin. DE-SCEND´ENS. [L. _de_ and _scando_, to climb.] Descending, falling. DI´A-PHRAGM. [Gr. +diaphragma+, _diaphragma_, a partition.] The midriff; a muscle separating the chest from the abdomen. DI-AR-RHOE´A. [Gr. +diarreô+, _diarrheo_, to flow through.] A morbidly frequent evacuation of the intestines. DI-AS´TO-LE. [Gr. +diastellô+, _diastello_, to put asunder.] The dilatation of the heart and arteries when the blood enters them. DI-GES´TION. [L. _digestio_.] The process of dissolving food in the stomach, and preparing it for circulation and nourishment. DIG-I-TO´RUM. [L. _digitus_, a finger.] A term applied to certain muscles of the extremities. DOR´SAL. [L. _dorsum_, the back.] Pertaining to the back. DU-O-DE´NUM. [L. _duodenus_, of twelve fingers' breadth.] The first portion of the small intestine. DU´RA MA´TER. [L. _durus_, hard, and _mater_, mother.] The outermost membrane of the brain. DYS´EN-TER-Y. [Gr. +dys+, _dûs_, bad, and +enteria+, _enteria_, intestines.] A discharge of blood and mucus from the intestines attended with tenesmus. DYS-PEP´SI-A. [Gr. +dys+, _dûs_, bad, and +peptô+, _pepto_, to digest.] Indigestion, or difficulty of digestion. EN-AM´EL. [Fr.] The smooth, hard substance which covers the crown or visible part of a tooth. EP-I-DERM´IS. [Gr. +epi+, _epi_, upon, and +derma+, _derma_, the skin.] The scarf-skin; the cuticle. EP-I-GLOT´TIS. [Gr. +epi+, _epi_, upon, and +glôtta+, _glôtta_, the tongue.] One of the cartilages of the glottis. EU-STA´CHI-AN TUBE. A channel from the fauces to the middle ear, named from Eustachius, who first described it. EX´CRE-MENT. [L. _excerno_, to separate.] Matter excreted and ejected; alvine discharges. EX-CRE-MEN-TI´TIAL. Pertaining to excrement. EX´CRE-TO-RY. A little duct or vessel, destined to receive secreted fluids, and to excrete or discharge them; also, a secretory vessel. EX-HA´LANT. [L. _exhalo_, to send forth vapor.] Having the quality of exhaling or evaporating. EX-TENS´OR. [L.] A name applied to a muscle that serves to extend any part of the body; opposed to _Flexor_. FA´CIAL. [L. _facies_, face.] Pertaining to the face. FALX. [L. _falx_, a scythe.] A process of the dura mater shaped like a scythe. FAS´CI-A. [L. _fascia_, a band.] A tendinous expansion or aponeurosis. FAS-CIC´U-LUS, -LI. [L. _fascis_, a bundle.] A little bundle. FAUX, -CES. [L.] The top of the throat. FEM´O-RAL. Pertaining to the femur. FEM´O-RIS. A term applied to muscles that are attached to the femur. FE´MUR. [L.] The thigh-bone. FE-NES´TRA, -UM. [L. _fenestra_, a window.] A term applied to some openings into the internal ear. FI´BRE. [L. _fibra_.] An organic filament, or thread, which enters into the composition of every animal and vegetable texture. FI´BRIN. A peculiar organic substance found in animals and vegetables; it is a solid substance, tough, elastic, and composed of thready fibres. FI´BROUS. Composed or consisting of fibres. FI´BRO-CAR´TI-LAGE. An organic tissue, partaking of the nature of fibrous tissue and that of cartilage. FIB´U-LA. [L., a clasp.] The outer and lesser bone of the leg. FIB´U-LAR. Belonging to the fibula. FIL´A-MENT. [L. _filamenta_, threads.] A fine thread, of which flesh, nerves, skin, &c., are composed. FLEC´TION. [L. _flectio_.] The act of bending. FOL´LI-CLE. [L. _folliculus_, a small bag.] A gland; a little bag in animal bodies. FORE´ARM. The part of the upper extremity between the elbow and hand. FOS´SA. [L., a ditch.] A cavity in a bone, with a large aperture. FR�´NUM. [L., a bridle.] _Frænum linguæ._ The bridle of the tongue. FUNC´TION. [L. _fungor_, to perform.] The action of an organ or system of organs. FUN´GI-FORM. [L. _fungus_ and _forma_.] Having terminations like the head of a fungus, or a mushroom. GAN´GLI-ON, -A. [Gr.] An enlargement in the course of a nerve. GAS´TRIC. [Gr. +gastêr+, _gastêr_, the stomach.] Belonging to the stomach. GAS-TROC-NE´MI-US. [Gr. +gastêr+, _gastêr_, the stomach, and +knêmê+, _knêmê_, the leg.] The name of large muscles of the leg. GEL´A-TIN. [L. _gelo_, to congeal.] A concrete animal substance, transparent and soluble in water. GLE´NOID. [Gr. +glênê+, _glênê_, a cavity.] A term applied to some articulate cavities of bones. GLOS´SA. [Gr.] The tongue. Names compounded with this word are applied to muscles of the tongue. GLOS´SO-PHA-RYN´GI-AL. Relating to the tongue and pharynx. GLOT´TIS. [Gr.] The narrow opening at the upper part of the larynx. GLU´TE-US. [Gr.] A name given to muscles of the hip. HEM´OR-RHAGE. [Gr. +haima+, _haima_, blood and +rêgnuô+, _rêgnuo_, to burst.] A discharge of blood from an artery or vein. HU´MER-US. [L.] The bone of the arm. HY´A-LOID. [Gr.] A transparent membrane of the eye. HY´DRO-GEN. [Gr. +hydôr+, water, and +gennaô+, to generate.] A gas which constitutes one of the elements of water. HY´GI-ENE. [Gr. +hugieinon+, _hugieînon_, health.] The part of medicine which treats of the preservation of health. HY´OID. [Gr. +u+ and +eidos+, _eîdos_, shape.] A bone of the tongue resembling the Greek letter upsilon in shape. HY-OID´E-US. Pertaining to the hyoid bone. HY´PO-GLOS´SAL. Under the tongue. The name of a nerve of the tongue. IL´E-UM. [Gr. +eilô+, _eilô_, to wind.] A portion of the small intestines. IL´I-AC. [From the above.] The flank; pertaining to the small intestine. IL´I-UM. The haunch-bone. IN-CI´SOR. [L. _incido_, to cut.] A front tooth that cuts or divides. IN´DEX. [L. _indico_, to show.] The fore-finger; the pointing finger. IN-NOM-I-NA´TA. [L. _in_, not, and _nomen_, name.] Parts which have no proper name. IN-OS´CU-LATE. [L. _in_ and _osculatus_, from _osculor_, to kiss.] To unite, as two vessels at their extremities. IN´TER. [L.] Between. IN-TER-COST´AL. [L. _inter_, between, and _costa_, a rib.] Between the ribs. IN-TER-NO´DI-I. [L. _inter_, between, and _nodus_, knot.] A term applied to some muscles of the forearm. IN-TER-STI´TIAL. [L. _inter_, between, and _sto_, to stand.] Pertaining to or containing interstices. IN-TES´TINES. [L. _intus_, within.] The canal that extends from the stomach to the anus. I´RIS. [L., the rainbow.] The colored circle that surrounds the pupil of the eye. I´VO-RY. A hard, solid, fine-grained substance of a fine white color; the tusk of an elephant. JE-JU´NUM. [L., empty.] A portion of the small intestine. JU´GU-LAR. [L. _jugulum_, the neck.] Relating to the throat. The great veins of the neck. LA´BI-UM, LA´BI-I. [L.] The lips. LAB´Y-RINTH. [Gr.] The internal ear, so named from its many windings. LACH´RY-MAL. [L. _lachryma_, a tear.] Pertaining to tears. LAC´TE-AL. [L., _lac_, milk.] A small vessel or tube of animal bodies for conveying chyle from the intestine to the thoracic duct. LAM´I-NA, -�. [L.] A plate, or thin coat lying over another. LAR´YNX. [Gr. +larunx+, _larunx_.] The upper part of the windpipe. LAR-YN-GI´TIS. Inflammation of the larynx. LA-TIS´SI-MUS, -MI. [L., superlative of _latus_, broad.] A term applied to some muscles. LE-VA´TOR. [L. _levo_, to raise.] A name applied to a muscle that raises some part. LIG´A-MENT. [L. _ligo_, to bind.] A strong, compact substance serving to bind one bone to another. LIN´E-A, -�. [L.] A line. LIN´GUA, -�. [L.] A tongue. LIV´ER. The name of one of the abdominal organs, the largest gland in the system. It is situated below the diaphragm, and secretes the bile. LOBE. A round projecting part of an organ. LON´GUS, LON´GI-OR. [L., long, longer.] A term applied to several muscles. LUM´BAR. [L. _lumbus_, the loins.] Pertaining to the loins. LYMPH. [L. _lympha_, water.] A colorless fluid in animal bodies, and contained in vessels called lymphatics. LYM-PHAT´IC. A vessel of animal bodies that contains or conveys lymph. MAG-NE´SI-UM. The metallic base of magnesia. MAG´NUS, -NA, -NUM. [L., great.] A term applied to certain muscles. MA´JOR. [L., greater.] Greater in extent or quantity. MAN´GA-NESE. A metal of a whitish gray color. MAR´ROW. [Sax.] A soft, oleaginous substance, contained in the cavities of bones. MAS-SE´TER. [Gr. +massaomai+, _massaomai_, to chew.] The name of a muscle of the face. MAS´TI-CATE, MAS-TI-CA´TION. [L. _mastico_.] To chew; the act of chewing. MAS´TOID. [Gr. +mastos+, _mastos_, breast, and +eidos+, _eîdos_, form.] the name of a process of the temporal bone behind the ear. MAS-TOID´E-US. A name applied to muscles that are attached to the mastoid process. MAX-IL´LA. [L.] The jaw-bone. MAX´IL-LA-RY. Pertaining to the jaw. MAX´I-MUS, -UM. [L., superlative of _magnus_, great.] A term applied to several muscles. ME-A´TUS. [L. _meo_, to go.] A passage or channel. ME-DI-AS-TI´NUM. A membrane that separates the chest into two parts. ME´DI-UM, -A. [L.] The space or substance through which a body passes to any point. MED´UL-LA-RY. [L., _medulla_, marrow.] Pertaining to marrow. ME-DUL´LA OB-LON-GA´TA. Commencement of the spinal cord. ME-DUL´LA SPI-NA´LIS. The spinal cord. MEM´BRA-NA. A membrane; a thin, white, flexible skin formed by fibres interwoven like net-work. MEM´BRA-NOUS. Relating to membrane. MES´EN-TER-Y. [Gr. +mesos+, _mesos_, the middle, and +enteron+, _enteron_, the intestine.] The membrane in the middle of the intestines, by which they are attached to the spine. MES-EN-TER´IC. Pertaining to the mesentery. MET-A-CAR´PAL. Relating to the metacarpus. MET-A-CAR´PUS. [Gr. +meta+, _meta_, after, and +karpos+, _karpos_, wrist.] The part of the hand between the wrist and fingers. MET-A-TAR´SAL. Relating to the metatarsus. MET-A-TAR´SUS. [Gr. +meta+, _meta_, after, and +tarsos+, _tarsos_, the tarsus.] The instep. A term applied to seven bones of the foot. MID´RIFF. [Sax. _mid_, and _hrife_, the belly.] See DIAPHRAGM. MIN´I-MUS, -I. [L.] The smallest. A term applied to several muscles. MI´NOR. [L.] Less, smaller. A term applied to several muscles. MI´TRAL. [L. _mitra_, a mitre.] The name of the valves in the left side of the heart. MO-DI´O-LUS. [L. _modus_, a measure.] A cone in the cochlea around which the membranes wind. MO´LAR. [L. _mola_, a mill.] The name of some of the large teeth. MOL´LIS. [L.] Soft. MO´TOR, -ES. [L. _moveo_, to move.] A mover. A term applied to certain nerves. MU´COUS. Pertaining to mucus. MU´CUS. A viscid fluid secreted by the mucous membrane, which it serves to moisten and defend. MUS´CLE. A bundle of fibres enclosed in a sheath. MUS´CU-LAR. Relating to a muscle. MY-O´DES. A term applied to certain muscles of the neck. NA´SAL. Relating to the nose. NA´SUS. [L., the nose.] The nostrils. NERVE. An organ of sensation and motion in animals. NERV´OUS. Relating to the nerves. NEU-RI-LEM´A. [Gr. +neuron+, _neuron_, a nerve, and +lemma+, _lema_, a sheath.] The sheath or covering of a nerve. NI´GRUM. [L.] Black. NI´TRO-GEN. That element of the air which is called azote. NU-TRI´TION. The art or process of promoting the growth, or repairing the waste of the system. OC-CIP-I-TA´LIS. Pertaining to the back part of the head. OC´CI-PUT. [L. _ob_ and _caput_, the head.] The hinder part of the head. OC-U-LO´RUM. Of the eyes. OC´ULUS, -I. [L.] The eye. OE-SOPH´A-GUS. [Gr. +oiô+, _oiô_, to carry, and +phagô+, _phago_, to eat.] The name of the passage through which the food passes from the mouth to the stomach. O-LEC´RA-NON. [Gr. +ôlene+, _ôlene_, the cubit, and +kranon+, _kranon_, the head.] The elbow; the head of the ulna. OL-FACT´O-RY. [L. _oleo_, to smell, and _facio_, to make.] Pertaining to smelling. O-MEN´TUM. [L.] The caul. O´MO. [Gr. +ômos+, _ômos_, the shoulder.] Names compounded of this word are applied to muscles attached to the shoulder. OPH-THAL´MIC. [Gr. +ophthalmos+, _ophthalmos_, the eye.] Belonging to the eye. OP-PO´NENS. That which acts in opposition to something. The name of two muscles of the hand. OP´TI-CUS, OP´TIC. [Gr. +optomai+, _optomai_, to see.] Relating to the eye. OR-BIC´U-LAR. [L. _orbis_, a circle.] Circular. OR-BIC-U-LA´RIS. A name applied to several muscles. OR´GAN. A part of the system destined to exercise some particular function. OR´I-GIN. Commencement; source. OS. [L.] A bone; the mouth of any thing. O´RIS. [L. _os_, _oris_.] Of the mouth. OS HY-OID´ES. [Gr. See HYOID.] The name of the bone at the base of the tongue. OS´MA-ZOME. [Gr. +osmê+, _osmê_, smell, and +zômos+, _zômos_, broth.] A principle obtained from animal fibre which gives the peculiar taste to broth. OS´SA. [L., plural of _os_, bone.] Bones. OS´SE-OUS. Pertaining to bones. OS-SI-FI-CA´TION. The formation of bones in animals. OS´SI-FY. [L. _ossa_, bones, and _facio_, to make.] To convert into bone. OS´SIS. Of a bone. O-VA´LE. [L.] The shape of an egg. OX-AL´IC. Pertaining to sorrel. _Oxalic acid_ is the acid of sorrel. It is composed of two equivalents of carbon and three of oxygen. OX´Y-GEN. A permanently elastic fluid invisible and inodorous. One of the components of atmospheric air. PA-LA´TUM. [L.] The palate; the roof of the mouth. PAL-PE-BRA´RUM. [L. _palpebra_, the eyelid.] Of the eyelids. PAL´MAR. [L. _palma_, the palm.] Belonging to the hand. PAL-MA´RIS. A term applied to some muscles attached to the palm of the hand. PAN´CRE-AS. [Gr. +pan+, _pan_, all, and +kreas+, _kreas_, flesh.] The name of one of the digestive organs. PAN-CRE-AT´IC. Belonging to the pancreas. PA-PIL´LA, -�. [L.] Small conical prominences. PA-RAL´Y-SIS. Abolition of function whether of intellect, sensation, or motion. PA-REN´CHY-MA. [Gr. +parencheô+, _parengcheô_, to pour through.] The substance contained between the blood vessels of an organ. PA-ROT´ID. [Gr. +para+, _para_, near, and +ôtos+, _ôtos_, the gen. of +ous+, _ous_, the ear.] The name of the largest salivary gland. PA-TEL´LA, -�. [L.] The knee-pan. PA-THET´I-CUS, -CI. [Gr. +pathos+, _pathos_, passion.] The name of the fourth pair of nerves. PEC´TUS. [L.] The chest. PEC´TO-RAL. Pertaining to the chest. PEC-TO-RA´LIS. Belonging to the chest. PE´DIS. [L., gen. of _pes_, the foot.] Of the foot. PEL´I-TONGS. A term applied to masses of fat. PEL´LI-CLE. [L., dim. of _pellis_, the skin.] A thin skin or film. PEL´VIC. Relating to the pelvis. PEL´VIS. [L.] The basin formed by the large bones at the lower part of the abdomen. PEN´NI-FORM. [L. _penna_, a feather.] Having the form of a feather, or quill. PER-I-CAR´DI-UM. [Gr. +peri+, _peri_, around, and +kardia+, _kardia_, the heart.] A membrane that encloses the heart. PER-I-CHON´DRI-UM. [Gr. +peri+, _peri_, around, and +chondros+, _chondros_, cartilage.] A membrane that invests cartilage. PER-I-CRA´NI-UM. [Gr. +peri+, and +kranion+, _kranion_, the cranium.] A membrane that invests the skull. PER´MA-NENT. Durable; lasting. PER-I-STAL´TIC. [Gr. +peristellô+, _peristello_, to involve.] A movement like the crawling of a worm. PER-SPI-RA´TION. [L. _per_, through, and _spiro_, to breathe.] The excretion from the skin. PHAL´ANX, -GES. [Gr. +phalanx+, _phalanx_, an army.] Three rows of small bones forming the fingers or toes. PHA-LAN´GI-AL. Belonging to the fingers or toes. PHA-RYN´GE-AL. Relating to the pharynx. PHAR´YNX. [Gr. +pharunx+, _pharunx_.] The upper part of the oesophagus. PHOS´PHOR-US. [Gr. +phôs+, _phôs_, the light, and +pherô+, _pherô_, to bear.] A combustible substance, of a yellowish color, semi-transparent, resembling wax. PHREN´IC. [Gr. +phrên+, _phrên_, the mind.] Belonging to the diaphragm. PHYS-I-OL´O-GY. [Gr. +phusis+, _phusis_, nature, and +logos+, _logos_, a discourse.] The science of the functions of the organs of animals and plants. PI´A MA´TER. [L., good mother.] The name of one of the membranes of the brain. PIG-MEN´TUM. [L.] Paint; a preparation of colors. PIN´NA. [L., a wing.] A part of the external ear. PLA-TYS´MA. [Gr. +platus+, _platûs_, broad.] A muscle of the neck. PLEU´RA, -�. [Gr. +pleura+, _pleura_, the side.] A thin membrane that covers the inside of the thorax, and also forms the exterior coat of the lungs. PLEU´RAL. Relating to the pleura. PLEX´US. [L. _plecto_, to weave together.] Any union of nerves, vessels, or fibres, in the form of net-work. PNEU-MO-GAS´TRIC. [Gr. +pneumôn+, _pneumôn_, the lungs, and +gastêr+, _gastêr_, the stomach.] Belonging to both the stomach and lungs. POL´LI-CIS. [L.] A term applied to muscles attached to the fingers and toes. PONS. [L.] A bridge. _Pons varolii._ A part of the brain formed by the union of the crura cerebri and cerebelli. POP-LIT-E´AL. [L. _poples_, the ham.] Pertaining to the ham or knee-joint. A name given to various parts. POS´TI-CUS. [L.] Behind; posterior. A term applied to certain muscles. POR´TI-O DU´RA. [L., hard portion.] The facial nerve; 8th pair. POR´TI-O MOL´LIS. [L., soft portion.] The auditory nerve; 7th pair. PO-TAS´SI-UM. [L.] The metallic basis of pure potash. PRO-BOS´CIS. [Gr. +pro+, _pro_, before, and +boskô+, _boskô_, to feed.] The snout or trunk of an elephant or other animal. PROC´ESS. A prominence or projection. PRO-NA´TOR. [L. _pronus_, turned downward.] The muscle of the forearm that moves the palm of the hand downward. PSO´AS. [Gr. +psoai+, _psoai_, the loins.] The name of two muscles of the leg. PUL-MON´IC. } } PUL´MO-NA-RY. } [L. _pulmo_, the lungs.] Belonging or } relating to the lungs. PUL-MO-NA´LIS. } PU´PIL. A little aperture in the centre of the iris, through which the rays of light pass to the retina. PY-LOR´IC. Pertaining to the pylorus. PY-LOR´US. [Gr. +pulôros+, _pulôros_, a gate keeper.] The lower orifice of the stomach, with which the duodenum connects. RA´DI-US. [L., a ray, a spoke of a wheel.] The name of one of the bones of the forearm. RA-DI-A´LIS. Radial; belonging to the radius. RA´DI-ATE. Having lines or fibres that diverge from a point. RA´MUS. [L.] A branch. A term applied to the projections of bones. REC-RE-MEN-TI´TIAL. [L. _re_, again, and _cerno_, to secrete.] Consisting of superfluous matter separated from that which is valuable. REC´TUM. The third and last portion of the intestines. REC´TUS, -I. [L.] Straight; erect. A term applied to several muscles. RE-SID´U-AL. Pertaining to waste matter. RE-SID´U-UM. [L.] Waste matter. The fæces. RES-PI-RA´TION. [L. _re_, again, and _spiro_, to breathe.] The act of breathing. Inspiring air into the lungs and expelling it again. RE-SPI´RA-TO-RY. Pertaining to respiration; serving for respiration. RET´I-NA. [L., _rete_, a net.] The essential organ of sight. One of the coats of the eye, formed by the expansion of the optic nerve. RO-TUN´DUM, -A. [L.] Round; circular. RU´GA, -�. [L.] A wrinkle; a fold. SAC´CU-LUS. [L., dim. of _saccus_, a bag.] A little sac. SA´CRAL. Pertaining to the sacrum. SA´CRUM. [L., sacred.] The bone which forms the posterior part of the pelvis, and is a continuation of the spinal column. SA-LI´VA. [L.] The fluid which is secreted by the salivary glands, which moistens the food and mouth. SAL´I-VA-RY. That which belongs to the saliva. SAN´GUIN-E-OUS. [L. _sanguis_, the blood.] Bloody; abounding with blood; plethoric. SAR-TO´RI-US. [L. _sartor_, a tailor.] A term applied to a muscle of the thigh. SCA´LA, -�. [L., a ladder.] Cavities of the cochlea. SCA-LE´NUS. [Gr. +skalênos+, _skalênos_, unequal.] A term applied to some muscles of the neck. SCAPH´OID. [Gr. +skaphê+, _skaphê_, a little boat.] The name applied to one of the wrist-bones. SCAP´U-LA. [L.] The shoulder-blade. SCAP´U-LAR. Relating to the scapula. SCARF-SKIN. The outer, thin integument of the body; the cuticle. SCI-AT´IC. [Gr., pertaining to the loins.] The name of the large nerve of the loins and leg. SCLE-ROT´IC. [Gr. +sklêros+, _sklêros_, hard.] A membrane of the eye. SE-BA´CEOUS. [L., _sebum_, tallow.] Pertaining to fat; unctuous matter. SE-CRE´TION. The act of secerning; the act of producing from the blood substances different front the blood itself, as bile, saliva. The matter secreted, as mucus, bile, &c. SE-CRE´TO-RY. Performing the office of secretion. SE-CUN´DUS. Second. A term applied to certain muscles. SEM-I-CIR´CU-LAR. Having the form of a half circle. The name of a part of the ear. SEM-I-TEN-DI-NO´SUS. [L. _semi_, half and _tendo_, a tendon.] The name of a muscle. SEP´TUM. [L.] A membrane that divides two cavities from each other. SE´ROUS. Thin; watery. Pertaining to serum. SE´RUM. [L.] The thin, transparent part of blood. SER-RA´TUS. [L. _serro_, to saw.] A term applied to some muscles of the trunk. SIG´MOID. [Gr.] Resembling the Greek +s+, sigma. SI-LI´CI-UM. A term applied to one of the earths. SI´NUS. [L., a bay.] A cavity, the interior of which is more expanded than the entrance. SKEL´E-TON. [Gr. +skellô+, _skellô_, to dry.] The aggregate of the hard parts of the body; the bones. SO´DI-UM. The metallic base of soda SPHINC´TER. [Gr. +sphingô+, _sphingo_, to restrict.] A muscle that contracts or shuts an orifice. SPI´NAL CORD. A prolongation of the brain. SPI-NA´LIS. Relating to the spine. SPINE. A thorn. The vertebral column; back-bone. SPI´NOUS. Belonging to the spinal column. SPLEEN. The milt. It is situated in the abdomen, and attached to the stomach. SPLEN´IC. Relating to the spleen. SPLE´NI-US. The name of a muscle of the neck. STA´PES. The name of one of the small bones of the ear. STER´NUM. The breast-bone. The bone that forms the front of the chest from the neck to the stomach. STOM´ACH. The principal organ of the digestive apparatus. STRA´TUM. [L. _sterno_, to stew.] A bed; a layer. STY´LOID. [L. _stylus_, a pencil.] An epithet applied to processes that resemble a style, a pen. SUB-CLA´VI-AN. [L. _sub_, under, and _clavis_, a key.] Situated under the clavicle. SUB-LI´MIS. High in place. SUB-LIN´GUAL. [L. _sub_, under, and _lingua_, the tongue.] Situated under the tongue. SUB-MAX´IL-LA-RY. [L. _sub_, under, and _maxilla_, the jaw-bone.] Located under the jaw. SUL´PHUR. A simple, mineral substance, of a yellow color, brittle, insoluble in water, but fusible by heat. SU-PE-RI-O´RIS. A term applied to certain muscles. SU-PI-NA´TOR. [L.] A muscle that turns the palm of the hand upward. SUT´URE. [L. _suo_, to sew.] The seam or joint that unites the bones of the skull. SYN-O´VI-A. [Gr. +syn+, _sûn_, with, and +ôon+, _ôon_, an egg.] The fluid secreted into the cavities of joints for the purpose of lubricating them. SYN-O´VI-AL. Pertaining to synovia. SYS´TEM. An assemblage of organs composed of the same tissues, and intended for the same functions. SYS-TEM´IC. Belonging to the general system. SYS´TO-LE. [Gr. +systellô+, _sûstellô_, to contract.] The contraction of the heart and arteries for expelling the blood and carrying on the circulation. TAR´SAL. Relating to the tarsus. TAR´SUS. [L.] The posterior part of the foot. TEN´DON. [Gr. +teinô+, _teino_, to stretch.] A hard, insensible cord, or bundle of fibres, by which a muscle is attached to a bone. TEN´DI-NA, -�. Pertaining to a tendon. TENS´OR. A muscle that extends a part. TEN-TAC´U-LA, -�. [L. _tento_, to seize.] A filiform process or organ on the bodies of various animals. TEN-TO´RI-UM. [L. _tendo_, to stretch.] A process of the dura mater which lies between the cerebrum and cerebellum. TE´RES. [L. _teres_, round.] An epithet given to many organs, the fibres of which are collected in small bundles. THO´RAX. [Gr.] That part of the skeleton that composes the bones of the chest. The cavity of the chest. THO-RAC´IC. Relating to the chest. THY´ROID. [Gr. +thureos+, _thureos_, a shield.] Resembling a shield. A cartilage of the larynx. TIB´I-A. [L., a flute.] The large bone of the leg. TIB-I-A´LIS, TIB´I-AL. Relating to the tibia. TIS´SUE. The texture or organization of parts. TON´SIL. [L.] A glandular body in the throat or fauces. TRA´CHE-A. [Gr. +trachus+, _trachus_, rough.] The windpipe. TRA´CHE-AL. Belonging to the trachea. TRANS-VERSE´, TRANS-VER-SA´LIS. Lying in a cross direction. TRA-PE´ZI-US. The name of a muscle, so called from its form. TRI´CEPS. [L. _tres_, three, and _caput_, head.] Three. A name given to muscles that have three attachments at one extremity. TRI-CUS´PID. [L. _tres_, three, and _cuspis_, point.] The triangular valves in the right side of the heart. TROCH´LE-A. [Gr. +trochalia+, _trochalia_, a pulley.] A pulley-like cartilage, over which the tendon of a muscle of the eye passes. TROCH-LE-A´RIS. The name of a muscle of the eye. TRUNK. The principal part of the body, to which the limbs are articulated. TU´BER-CLE. [L. _tuber_, a bunch.] A small push, swelling, or tumor, on animal bodies. TU-BER-OS´I-TY. The state of being knobbed or protuberant. TYM´PAN-UM. [L.] The middle ear. UL´NA. [L.] A bone of the forearm. UL´NAR, UL-NA´RIS. Relating to the ulna. U´RIC. [Gr. +ouron+, _ouron_, urine.] An acid contained in urine, and in gouty concretions. U-VE´A. [L. _uva_, a grape.] Resembling grapes. A thin membrane of the eye. U´VU-LA. A soft body, suspended from the palate, near the aperture of the nostrils, over the glottis. VAC´CINE VI´RUS. [L. _vacca_, a cow, _virus_, poison.] Pertaining to cows; derived from cows. VALVE. Any membrane, or doubling of any membrane, which prevents fluids from flowing back in the vessels and canals of the animal body. VAL´VU-LA, -�. A valve. VAS´CU-LAR. [L. _vasculum_, a vessel.] Pertaining to vessels; abounding in vessels. VAS´TUS. [L.] Great, vast. Applied to some large muscles. VEINS. Vessels that convey blood to the heart. VE´NOUS. Pertaining to veins. VEN´TRI-CLE. [L. _venter_, the stomach.] A small cavity of the animal body. VEN-TRIC´U-LAR. Relating to ventricles. VER-MIC´U-LAR. [L. _vermiculus_, a little worm.] Resembling the motions of a worm. VERM-I-FORM´IS. [L. _vermis_, a worm, and _forma_, form.] Having the form and shape of a worm. VERT´E-BRA, -�. [L. _verto_, to turn.] A joint of the spinal column. VERT´E-BRAL. Pertaining to the joints of the spinal column. VES´I-CLE. [L. _vesica_, a bladder.] A little bladder, or a portion of the cuticle separated from the cutis vera and filled with serum. VES´TI-BULE. [L.] A porch of a house. A cavity belonging to the ear. VIL´LI. [L.] Fine, small fibres. VI´RUS. [L. poison.] Foul matter of an ulcer; poison. VI´TAL. [L. _vita_, life.] Pertaining to life. VIT´RE-OUS. [L. _vitrum_, glass.] Belonging to glass. A humor of the eye. VO´LAR. [L. _vola_, the hollow of the hand or foot.] Belonging to the palm of the hand. VO´MER. [L. a ploughshare.] One of the bones of the nose. ZYG-O-MAT´I-CUS. [Gr. +zugos+, _zugos_, a yoke.] A term applied to some muscles of the face, from their attachment. INDEX. A. PAGE. ABDOMEN, 34 ABSORPTION, 181 ----, Varieties of, 183 ----, Cutaneous, 185 ACETABULUM, 38 ACIDS, Acetic, 28 ----, Benzoic, 28 ----, Muriatic, 440 ----, Nitric, 440 ----, Oxalic, 28, 440 ----, Sulphuric, 440 AIR, Composition of the, 223 ----, Influence of, on the Muscles, 90 ----, Quality of the, 223, 318 ----, Quantity inhaled, 222 ----, Quantity exhaled, 228 ----, Impure Air, the Effects of, 232 AIR VESICLES, 212 ALBUMEN, 27 ANIMAL HEAT, 252 AORTA, 159 ----, Valves of the, 157 APPARATUS, 18 ARTERIES, Structure of the, 158 ----, Cutaneous, 285 ----, Pulmonary, 158 ATTITUDE, Effects of, on Digestion, 152 ----, Effects of, on the Voice, 274 ----, Effects of, in Respiration, 245 AURICLES of the Heart, 156 ASPHYXIA, from Drowning, 249 ----, from Electricity, 250 ----, from Hanging, 250 ----, from Carbonic Gas, 251 AZOTE, 26 B. BATHING, Necessity of, 311 ----, Methods of, 313 ----, Proper Time for, 316 ----, Influence of, on the System, 316 ----, Frequency of, 317 BEDS, 309 BILE, 122 BLOOD, Composition of, 154 ----, Color of, 204 ----, Quantity of, 171 ----, Change of, 225 ----, Impure, Effects of, 205 BONES, Anatomy of the, 29 ----, Physiology of the, 48 ----, Hygiene of the, 53 ----, of the Head, 32 ----, of the Trunk, 34 ----, of the Upper Extremities, 39 ----, of the Lower Extremities, 42 ----, Composition of, 29 ----, Ossification of, 30 ----, Union of fractured, 62 ----, Influence of Position on the, 55 BRAIN, 329 ----, Functions of the, 346 ----, Effects of Impure Blood on the, 360 ----, Effects of inadequate Mental Exertion, 361 ----, Effects of excessive Mental Exertion, 363 ----, Directions for exercising the, 368 ----, Membranes of the, 334 ----, Injuries of the, 377 BRONCHIA, 212 BRONCHITIS, 214 BURNS AND SCALDS, 319 BURS� MUCOS�, 46 C. C�CUM, 118 CAPILLARIES, 163 CARBON, 26 CARBONIC GAS, where formed, 224 ----, Effects of, when inhaled, 230 ----, Effects of, on Combustion, 230 ----, Effects of, on Respiration, 231 CARPUS, 41 CARTILAGE, 45 ---- of the Larynx, 269 CAUL, 123 CELLULAR TISSUE, 19 CEREBELLUM, 331 CEREBRUM, 330 CHEST, 35 ----, Compression of the, 56 ----, Influence of the Size of the, 239 CHILBLAINS, 321 CHLORINE, 27 CHYLE, 126 CHYME, 126 CIRCULATORY ORGANS, Anatomy, 154 ----, Physiology of the, 164 ----, Hygiene of the, 172 CLAVICLE, 39 CLOTHING, Kind of, 301 ----, Amount of, 305 ----, Cleanliness of, 308 COCCYX, 38 COLDS, Treatment of, 248 COLON, 119 CONSUMPTION, how frequently produced, 247 CORNS, Treatment of, 295 CUTICLE, Structure of the, 282 ----, Use of the, 293 CUTIS VERA, Structure of the, 283 D. DEFINITIONS, General, 13 DIAPHRAGM, 73, 215 DIGESTIVE ORGANS, Anatomy of the, 113 ----, Physiology of the, 124 ----, Hygiene of the, 129 ----, Influence of the Mind on the, 148 ----, Influence of Pure Air on the, 151 ----, Influence of Position on the, 152 DRINKS, how taken, 145 DROWNED PERSONS, Treatment of, 249 DUODENUM, 117 E. EAR, Bones of, 34, 415 EPIGLOTTIS, 125, 270 EXHALANTS, 192 EXERCISE, how it should be taken, 91 ----, Influence of, on the Bones, 53 ----, Influence of, on Muscles, 85 ----, Influence of, on the Circulation, 173 EYE, 394 EXPIRATION, how effected, 220 F. FACE, Bones of the, 34 FASCIA, 66 FAT, 67, 195 FEMUR, 42 FIBRE, 18 FIBRIN, 27 FIBULA, 42 FILAMENT, 18 FLANNEL, Use of, 302 FLUIDS, Use of, 17 FOLLICLE, 192 FOOD, Quantity of the, 129 ----, Quality of the, 134 ----, Manner in which it is taken, 142 ----, Condition of the system, when taken, 146 FOOT, Bones of the, 44 FROZEN LIMBS, Treatment of, 320 G. GASTRIC JUICE, 125 GELATIN, 27 GLANDS, 193 ----, Gastric, 116 ----, Lachrymal, 402 ----, Lymphatic, 183 ----, Mesenteric, 121 ----, Oil, 288 ----, Perspiratory, 290 ----, Salivary, 114 GLOTTIS, 271 H. HAIR, 322 HEART, 154 ----, Auricles of the, 156 ----, Ventricles of the, 156 HEAT, Animal, 252 ----, Hygiene of, 261 HEARING, Anatomy of the Organs of, 414 ----, Physiology of the Organs of, 420 ----, Hygiene of the Organs of, 422 HUMERUS, 39 HEMORRHAGE, Means of arresting, 175 HYDROGEN, 26 I. ILEUM, 118 INTESTINES, 117 INNOMINATUM, 37 INSPIRATION, how effected, 219 IRON, 25 J. JEJUNUM, 118 JOINTS, Structure of the, 45 L. LACTEALS, 120, 181 LAMIN�, 17 LARYNX, 268 LARYNGITIS, 276 LIGAMENTS, 23, 47 ----, Use of, 50 ----, Capsular, 40 LIGHT, Influence on the Skin, 318 LIME, 25 LIVER, 122 LUNGS, 209 LYMPH, 30 LYMPHATICS, Anatomy of the, 181 ----, Physiology of the, 183 ----, Hygiene of the, 188 ----, Cutaneous, 287 M. MAGNESIA, 25 MARROW, Uses of, 24 MEDIASTINUM, 211 MEDULLA OBLONGATA, 333 MEMBRANE, 19 ----, Adipose, 20 ----, Cellular, 19 ----, Dermoid, 22, 282 ----, Mucous, 21 ----, Muscular, 24 ----, Serous, 21 MESENTERY, 120 METACARPUS, 41 MOUTH, Structure of, 113 MUCUS, 28 MUSCLES, Anatomy of, 64 ----, Physiology of, 76 ----, Hygiene of, 85 ----, Compression of, 93, 276 ----, Exhaustion of, 87, 101 ----, Effects of Pure Blood on, 89 ----, Effects of Pure Air on the, 90 ----, Effects of Light on the, 90 ----, Influence of the Mind on, 93 ----, Influence of Position on, 90 ----, Intercostal, 216 ----, Respiratory, 216 N. NAILS, 324 NERVES, Cranial, 335, 350 ----, Cutaneous, 286 ----, Respiratory, 340, 352 ----, Spinal, 341, 351 ----, Sympathetic, 343, 356 NERVOUS SYSTEM, Anatomy of, 327 ----, Physiology of, 346 ----, Hygiene of, 358 NITROGEN, 26 NOSE, Structure, 389 NURSES, Directions for, 433 NUTRITION, 200 ----, Hygiene of, 205 O. OESOPHAGUS, 116 OIL-GLANDS, Structure of the, 288 ----, Use of the, 297 OMENTUM, 123 ORGAN, 18 ORGANIC AND INORGANIC BODIES, Difference between, 14 ORIFICE, Cardiac, 116 ----, Pyloric, 116 OSMAZOME, 28 OXYGEN, 26 ----, Quantity at each Inspiration, 222 P. PAPILLA, 284 PANCREAS, 122 PAROTID GLAND, 114 PATELLA, 42 PERICARDIUM, 155 PERICHONDRIUM, 31 PERICRANIUM, 31 PERIOSTEUM, 31 PELVIS, Bones of the, 37 PERSPIRATORY APPARATUS, 290 ---- Use of, 298 PHALANGES, 42, 45 PHARYNX, 115 PHOSPHORUS, 26 PLEURA, 211 POISONS, and their Antidotes, 439 POTASH, 25 PRESERVATION OF HEALTH, 425 R. RADIUS, 41 READING, Proper Position in, 275 RECTUM, 120 REMOVAL OF DISEASE, 426 RESPIRATORY ORGANS, Anatomy of, 209 ----, Physiology of, 217 ----, Hygiene of, 228 RETINA, 397 RIBS, 35 ROOMS, Ventilation of, 233 ----, Warming of, 238 S. SACRUM, 38 SALIVA, Its Use, 124 SCAPULA, 39 SECRETORY ORGANS, Anatomy of, 192 ----, Physiology of, 193 ----, Hygiene of, 197 SENSES, 378 SICK-ROOM, Ventilation of, 236 SITTING, Proper Position in, 99 SKELETON, 29 SKIN, Anatomy of the, 282 ----, Physiology of the, 293 ----, Hygiene of the, 301 SKULL, Structure of, 32 SLEEP, Necessity of, 92 SLEEPING-ROOMS, Ventilation of, 235 SMELL, Anatomy of the Organs of, 389 ----, Physiology of the Organs of, 391 SODA, 25 SOLIDS, Arrangement of, 17 SOUND, 273 SPINAL COLUMN, Structure of, 36 ----, Curvature of, 57, 60 SPINAL CORD, 36, 340 SPLEEN, 123 SPRAINS, 63 STAMMERING, how improved, 281 STERNUM, 35 STOMACH, 116 SUBLINGUAL GLAND, 115 SUBMAXILLARY GLAND, 115 SULPHUR, 26 SUTURES, 33 SYNOVIAL MEMBRANE, 46 SYNOVIA, 49 SYSTEM, 18 T. TARSUS, 42 TASTE, Anatomy of the Organs of, 384 ----, Physiology of the Organs of, 386 TEETH, Anatomy of the, 105 ----, Physiology of the, 109 ----, Hygiene of the, 110 TENDONS, 23, 65 THORACIC DUCT, 120 THORAX, 35 THROAT, Extraneous Bodies in, 281 TIBIA, 42 TISSUE, 18 ----, Adipose, 20 ----, Cartilaginous, 23 ----, Fibrous, 22 ----, Osseous, 23 ----, Nervous, 24 TOUCH, Sense of, 378 ----, Hygiene of the, 379 TRACHEA, 212 U. ULNA, 40 UVEA, 396 V. VALVES of the Heart, 157 ----, Use of the, 164 ----, of the Veins, 162 VEINS, 160 ----, Cutaneous, 285 VENTILATION, 233 VENTRICLES of the Heart, 156 VERTEBRA, 36 VISION, Anatomy of the Organs of, 394 ----, Physiology of the Organs of, 404 ----, Hygiene of the Organs of, 410 VOCAL ORGANS, Anatomy of the, 268 ----, Physiology of the, 272 ----, Hygiene of the, 274 VOCAL CORDS, 270 W. WATCHERS, Directions for, 136 WOUNDS, Treatment of, 178 WRITING, Proper Position when, 103 KEY TO ANATOMICAL OUTLINE PLATES. SUGGESTIONS TO TEACHERS. In using these plates, we would suggest, that the pupil carefully examine the illustrating cuts interspersed with the text, in connection with the lesson to be recited. The similarity between these and the plates will enable the pupil to recite, and the teacher to conduct his recitation, from the latter. Let a pupil show the situation of an organ, or part, on an anatomical outline plate, and also give its structure; while other members of the class note all omissions and misstatements. Another pupil may give the use of that organ, and if necessary, others may give an extended explanation. The third may explain the laws on which the health of the part depends, while other members of the class supply what has been omitted. After thus presenting the subject in the form Of topics, questions may be proposed promiscuously, from each paragraph, and where examples occur in the text, let other analogous ones be given. If the physiology and hygiene of a given subject have not been studied, confine the recitation to those parts only on which the pupil is prepared. When practicable, the three departments should be united; but this can only be done when the chapter on the hygiene has been learned, while the physiology can be united with the anatomy, in all chapters upon physiology. PLATE I. A FRONT VIEW OF THE SKELETON. _Bones of the Head._ 7, The sphenoid bone. 8, The frontal bone. 10, The parietal bone. 11, The os unguis. 12, The superior maxillary bone, (upper jaw.) 13, The nasal bone. 14, The ethmoid bone. 15, The malar bone, (cheek-bone.) 16, The vomer. 17, The inferior maxillary bone, (the lower jaw.) _a_, Its body. _b_, Its ramus, or branch. 18, The teeth. _Bones of the Trunk._ 1, 1, The spinal column. 2, The sternum. 3, 3, The ribs. 4, The sacrum. 5, The innominatum. _Bones of the Upper Extremities._ 19, The clavicle, (collar-bone.) 20, The scapula, (shoulder blade.) 21, The humerus. 22, The ulna. 23, The radius. 24, 25, 26, 27, 28, 29, 30, 31, The bones of the carpus (wrist.) 32, 32, 32, The five bones of the metacarpus, (the palm of the hand.) 33, 33, 33, The first range of finger-bones. 34, 34, The second range of finger-bones. 35, 35, 35, The third range of finger-bones. _Bones of the Lower Extremities._ 36, The femur, (thigh-bone.) 37, The patella, (knee-pan.) 38, The tibia, (shin-bone.) 39, The fibula. 40, 40, 40, The bones of the tarsus, (instep.) 41, 41, The bones of the metatarsus, (middle of the foot.) 42, 42, The bones of the toes. ARTICULATIONS. (Left side of the plate.) _Ligaments of the Trunk._ 1, 1, The common spinal ligament. 2, 2, The intervertebral ligament, (cartilage between the vertebrae.) 9, 10, 11, 12, Articulations of the ribs with the spinal column. 13, 13, 14, 15, 16, Ligaments that connect the cartilages of the ribs with the sternum. _Ligaments of the Upper Extremities._ 25, The ligament that connects the clavicle and sternum. 27, The ligament that connects the upper rib and clavicle. 28, 29, 30, Ligaments that connect the clavicle and scapula. 31, 32, 33, 34, Ligaments of the shoulder-joint. 35, 35, 36, Ligaments of the elbow-joint. 37, 38, 39, 40, Ligaments of the wrist. 41, 42, 43, 44, Ligaments of the fingers. _Ligaments of the Lower Extremities._ 49, 49, Ligaments of the hip-joint. 50, 50, Ligaments of the patella. 51, 52, 53, 54, 55, Ligaments of the knee-joint. 56, A large bursa mucosa. 57, The ligament of the tibia and fibula. 58, 58, The interosseous ligament. 59, 59, Ligaments of the ankle-joint 60, 61, 62, Ligaments of the metatarsus. 63, 64, Ligaments of the toes. A, The brachial artery. B, The brachial vein. C, The radial artery D, The femoral artery. E, The femoral vein. F, G, The anterior tibia artery. PLATE II. A BACK VIEW OF THE SKELETON. _Bones of the Head._ 5, The occipital bone. 6, The parietal bone. 7, The temporal bone. 8, The frontal bone. 9, The sphenoid bone. 15, The malar bone. 16, The nasal bone. 17, The superior maxillary bone, (upper jaw.) 18, The inferior maxillary bone, (lower jaw.) 19, The teeth. _Bones of the Trunk._ 1, 1, The spinal column. 2, The sacrum. 3, The coccyx. 20, The innominatum. 4, 4, The ribs. _Bones of the Upper Extremities._ 21, The clavicle, (collar-bone.) 22, The scapula, (shoulder-blade.) 23, The humerus. 24. The ulna, 25, The radius. 26, 27, 28, 29, 30, 31, 32, The bones of the carpus, (wrist.) 33, 33, 33, The bones of the metacarpus, (palm of the hand.) 34, 34, 34, The first range of finger-bones. 35, 35, The second range of finger-bones. 36, 36, 36, The third range of finger-bones. _Bones of the Lower Extremities._ 37, The femur, (thigh-bone.) 38, The patella, (knee-pan.) 39, The tibia, (shin-bone.) 40, The fibula. 41, 42, 43, 44, 45, The bones of the tarsus, (instep.) 46, 46, The bones of the metatarsus, (middle of the foot.) 47, 47, Bones of the toes. ARTICULATIONS. (Left side of the plate.) _Ligaments of the Trunk._ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Ligaments of the spinal column. 14, 14, 15, 15, Ligaments that connect the ribs and spinal column. 11, 11, 21, 22, 23, 24, 25, 26, Ligaments that connect the sacrum and innominatum. _Ligaments of the Upper Extremities._ 27, 28, Ligaments that connect the clavicle and scapula. 29, The capsular ligament of the shoulder-joint. 30, 30, Ligaments of the elbow. 31, 32, 33, 34, Ligaments of the carpus, (wrist.) _Ligaments of the Lower Extremities._ 9, Tendon of the gluteus muscle. 35, The capsular ligament of the hip-joint. 36, 36, Ligaments of the knee-joint. 37, The ligament that connects the tibia and fibula. 38, The interosseous ligament. 39, 40, Ligaments of the ankle-joint. PLATE III. A FRONT VIEW OF THE MUSCLES. _Muscles of the Head and Neck._ 7, The sterno-mastoideus muscle. 8, The sterno-hyoideus muscle. 9, The omo-hyoideus muscle. 10, The trapezius muscle. 11, The orbicularis oculi muscle. 12, The frontal muscle. 14, The orbicularis oris muscle. 15, The elevator muscle of the nostrils. 16, The zygomatic muscle. 17, The depressor of the lower lip. 18, The depressor anguli oris muscle. 19, The triangular muscle of the nose. 20, 21, The aural muscles. 22, The masseter muscle. _Muscles of the Trunk._ 2, 3, The external oblique muscles. _Muscles of the Upper Extremities._ 1, The grand pectoral muscle. 3, 4, The serratus muscle. 23, The deltoid muscle. 24, The biceps brachialis muscle. 25, The coraco-brachialis muscle. 26, The anterior brachial muscle. 27, The triceps brachialis muscle. 28, The long supinator muscle. 29, The external radial muscle. 30, The pronator teres muscle. 31, The anterior radial muscle. 32, The palmaris brevis muscle. 33, The anterior ulnar muscle. 35, The palmar muscle. 36, The abductor muscle of the thumb. 37, The adductor muscle of the thumb. 38, 39, Small flexor muscles of the thumb. 40, The abductor muscle of the little finger. 41, 41, The lumbricales muscles. 61, 61, The bifurcation of the tendons of the superficial flexor muscle, in the fingers. _Muscles of the Lower Extremities._ 42, The fascia lata muscle. 43, The sartorius muscle. 44, The rectus femoris muscle. 45, The vastus externus muscle. 46, The vastus internus muscle. 47, The internal straight muscle. 48. The pectineus muscle. 49, The adductor muscle. 50, The psoas muscle. 51, The tibialis anticus muscle. 52, The long extensor muscle of the great toe. 53, The long extensor muscle of the toes. 54, The anterior peroneal muscle. 55, The long lateral peroneal muscle. 56, 57, The gastrocnemii muscles. 58, The long flexor muscle of the great toe. 69, The short extensor muscles of the toes. 60, The abductor muscle of the great toe. The figures and letters on the left side of the plate, indicate the position of important fasciæ, that cover the muscles and enclose the tendons. PLATE IV. BACK VIEW OF THE MUSCLES. _Muscles of the Head and Neck._ 4, The sterno-mastoideus muscle. 5, The complexus muscle. 6, The mylo-hyoideus muscle. 7, 8, The occipito-frontalis muscle. 9, The masseter muscle. 10, 11, 12, The anterior, middle, and posterior aural muscles. 13, The temporal muscle. _Muscles of the Trunk._ 1, 1, The trapezius muscle. 2, The latissimus dorsi muscle. 3, The rhomboideus muscle. 4, The external oblique muscle. _Muscles of the Upper Extremities._ 5, The deltoid muscle. 6, 7, The infra-spinatus muscle. 9, The triceps extensor muscle. 10, The internal brachial muscle. 11, The long supinator muscle. 12, The external radial muscle. 13, The second external radial muscle. 14, The anconeus muscle. 15, 16, The extensor digitorum communis muscle. 17, The extensor carpi ulnaris muscle. 18, The flexor carpi ulnaris. 19, 20, The extensor ossis metacarpi pollicis muscles. 21, An extensor muscle of the thumb. 22, 28, Interossii muscles. _Muscles of the Lower Extremities._ 29, The gluteus maximus muscle. 30, The gluteus medius muscle. 31, The biceps flexor cruris muscle. 32, The semi-tendinosus muscle. 33, The semi-membranosis muscle. 34, The gracilis muscle. 35, The adductor muscle. 36, The vastus externus muscle. 37, The sartorius muscle. 38, 39, The gastrocnemii muscles. 40, The long peroneal muscle. 41, The external peroneal muscle. 42, The long flexor muscle of the great toe. 43, The long extensor muscle of the toes. 44, The short extensor muscle of the toes. 47, The short flexor muscle of the toes. The figures and letters on the left side of the plate, indicate the position of membranous fasciæ which envelop the muscles and tendons. PLATE V. ORGANS OF THE THORAX AND ABDOMEN. Fig. 1. _The Mouth and Neck._ (A Side view.) 1, The upper lip. 2, The lower lip. 3, The upper jaw. 4, The lower jaw. 5, The tongue. 6, The hard palate, (roof of the mouth.) 7, The parotid gland. 8, The sublingual gland. T, The larynx. 10, The pharynx. 11, The oesophagus. 12, The upper portion of the spinal column. C, The spinal cord. _The Chest and its Organs._ 9, 9, The trachea. R, The right auricle of the heart. L, The left auricle. 13, The left ventricle of the heart. 14, The right ventricle. 15, The aorta. 16, The pulmonary artery. 17, The vena cava descendens. 18, The right subclavian vein. 19, The left subclavian vein. 20, The right jugular vein. 21, The left jugular vein. 22, The right carotid artery. 23, The left carotid artery. 24, 25, 26, The upper, middle, and lower lobes of the right lung. 27, 28, The upper and lower lobes of the left lung. 29, 29, 29, The diaphragm. P, P, P, P, The pleura, that lines the cavity of the chest. S, S, The clavicles. O, O, O, O, The ribs. M, M, M, M, Muscles of the chest. 40, The thoracic duct, opening into the left subclavian vein. _The Abdomen and its Organs._ 30, The stomach. 31, 32, The right and left lobe of the liver. F, The fissure that separates the two lobes. 33, The gall bladder. 34, 34, The duodenum. 35, The ascending colon. 36, The transverse colon. 37, The descending colon. 38, 38, 38, 38, The small intestine. 39, 39, The walls of the abdominal cavity turned down. 41, The spleen. Fig. 2. _The Relation of the Lacteals and Thoracic Duct._ 1, 1, A section of the small intestine. 2, 2, 2, 2, 2, 2, 2, 2, Mesenteric glands, through which the lacteals from the intestine pass. 3, Several lacteal vessels entering the enlarged portion and commencement of the thoracic duct. 5, 5, 5, The thoracic duct. 6, The thoracic duct opening into the left subclavian vein. 7, (See 40, Fig. 1.) 8, The right subclavian vein. 9, The vena cava descendens. 10, 11, 11, The aorta. 12, The carotid arteries. 13, 13, The jugular veins. 14, The vena azagos. 15, 15, The spinal column. 16, The diaphragm. Fig. 3. _The Relation of the Larynx, Trachea, Bronchia, and Air-cells._ 1, 1, 1, An outline of the right lung. 2, 2, 2, An outline of the left lung. 3, The larynx. 4, The trachea. 5, The right bronchia. 6, The left bronchia. 7, 7, 7, 7, Divisions of the right bronchia. 8, 8, 8, 8, Divisions of the left bronchia. 9, 9, 9, 9, 9, 9, Air-cells. Fig. 4. _An ideal View of a lateral and vertical Section of the Larynx._ 1, 1, The superior vocal cords, (ligaments.) 2, 2, The inferior vocal cords. 3, 3, The glottis. 4, 4, The ventricles of the larynx. PLATE VI. HEART, ARTERIES, AND VEINS Fig. 1. _The Heart and large Arteries._ 1, The right auricle of the heart. 2, The right ventricle of the heart. 3, The left auricle. 4, The left ventricle. 5, The pulmonary artery. 6, The aorta. 7, 7, The descending aorta. 8, The arteria innominata. 9, The left carotid artery. 10, The left subclavian artery. 56, The right subclavian artery. _Arteries of the Neck and Head._ 15, The right carotid artery. 16, The left carotid artery. 17, The right temporal artery. 50, The right facial artery. 54, The left temporal artery. _Arteries of the Upper Extremities._ 11, 11, The left brachial artery. 12, The left radial artery. 13, 13, The right brachial artery. 14, The right radial artery. 51, The right ulnar artery. _Arteries of the Lower Extremities._ 18, The left iliac artery. 19, The right iliac artery. 20, The left femoral artery. 21, The right femoral artery. 22, The peroneal artery. 23, The left anterior tibial artery. 24, The muscular artery. 25, 25, The right and left arteria profunda. 26, The right anterior tibial artery. 27, The right peroneal artery. _The Veins of the Neck and Head._ 28, The vena cava descendens. 29, The left subclavian vein. 30, The right subclavian vein. 31, The right jugular vein. 32, The left jugular vein. 53, The right temporal vein. 55, The left temporal vein. 49, The right facial vein. _Veins of the Upper Extremities._ 33, The left brachial vein. 34, The left radial vein. 35, The right brachial vein. 36, The right radial vein. 51, The right ulnar vein. _Veins of the Lower Extremities._ 37, The vena cava ascendens. 38, The left iliac vein. 39. The right iliac vein. 40, The left femoral vein. 41, The right femoral vein. 42, The left anterior tibial vein. 43, The left peroneal vein. 44, The right anterior tibial vein. 45, The right peroneal vein. 46, 46, The profunda veins. 47, The muscular veins. 48, 48, 48, 48, 48, 48, Intercostal arteries and veins. Fig. 2. _The Relation of the Cavities of the Heart to the large Blood-vessels._ 1, The vena cava descendens. 2, The vena cava ascendens. 3, The right auricle of the heart. 4, The opening between the right auricle and right ventricle. 5, The right ventricle. 6, The tricuspid valves. 7, The pulmonary artery. 8, 8, The branches of the pulmonary artery that pass to the right and left lung. 9, The semilunar valves of the pulmonary artery. 10, The left pulmonary veins. 11, The right pulmonary veins. 12, The left auricle. 13, The opening between the left auricle and left ventricle. 14, The left ventricle. 15, The mitral valves. 16, 16, The aorta. 17, The semilunar valves of the aorta. 18, The septum between the right and left ventricle. Fig. 3. _An ideal View of the Heart, Arteries, and Veins._ A, The right auricle. B, The right ventricle. C, The tricuspid valves. D, The opening between the right auricle and right ventricle. E, The left auricle. F, the left ventricle. G, The mitral valves. H, The opening between the left auricle and left ventricle. I, The septum between the right and left ventricle. K, The pulmonary artery. L, The semilunar valves of the pulmonary artery. M, M, The right pulmonary artery. N, N, The left pulmonary artery. O, O, O, O, O, O, The capillary vessels of the lungs. P, P, P, The right pulmonary vein. Q, Q, The left pulmonary vein. R, R, The aorta. S, The semilunar valves of the aorta. T, T, A branch of the aorta to the upper extremities. U, U, U, U, A branch to the lower extremities. V, V, V, V, V, V, The capillary vessels at the extremity of the branches of the aorta. W, W, The descending vena cava. X, X, X, The ascending vena cava. In Figs. 1, 2, 3, the course of the blood through the circulatory vessels is indicated by arrows. PLATE VII. THE PULMONARY CIRCULATION. Fig. 1. 1, The right auricle of the heart. 2, The left auricle. 3, The right ventricle of the heart. 4, The left ventricle. 5, The pulmonary artery. 6, The branch of the pulmonary artery to the left lung. 7, The branch of the pulmonary artery to the right lung. 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, Branches of the pulmonary artery in the right and left lung. 9, 9, 9, 9, 9, 9, Air-cells. 10, 10, 10, 10, 10, 10, 10, Small pulmonary veins in the right and left lung. 11, The left pulmonary vein. 12, 12, The right pulmonary vein. Fig. 2. _An ideal View of the Pulmonary Circulation._ 1, 1, The right lung. 2, 2, The left lung. 3, The trachea. 4, 4, 4, 4, 4, The right bronchia. 5, 5, 5, 5, 5, The left bronchia. 6, 6, 6, 6, 6, 6, Air-cells, with arteries and veins passing around them. 7, The right auricle of the heart. 8, The right ventricle of the heart. 9, The tricuspid valves. 10, The pulmonary artery. 11, 11, 11, 11, The right pulmonary artery. 12, 12, 12, 12, 12, The left pulmonary artery. 13, 13, 13, 13, The right pulmonary vein. 14, 14, 14, 14, The left pulmonary vein. 15, The left auricle. 16, The left ventricle. 17, The mitral valves. 18, The septum between the right and left ventricles. Fig. 3. _An ideal View of the Capillaries._ 1, 1, A branch of the pulmonary artery. 2, 2, A branch of the pulmonary vein. 3, 3, Capillary vessels between the artery and vein. Fig. 4. _An ideal View of the Relations of the Bronchia, Air-cells, Pulmonary Arteries, and Veins._ 1, A bronchial tube. 2, 2, 2, Air-cells. 3, A branch of the pulmonary artery. 4, A branch of the pulmonary vein. PLATE VIII. THE CEREBRUM, CEREBELLUM, SPINAL CORD, AND NERVES 1, The cerebrum. 2, The cerebellum. 3, 3, The spinal cord. 4, The brachial plexus of nerves. 5, The lumbar plexus of nerves. 6, The sacral plexus of nerves. 7, The facial nerve. 8, 17, The radial nerve. 9, 9, 16, The ulnar nerve. 10, The median nerve. G, The circumvex nerve of the shoulder. 11, 11, The great sciatic nerve. 12, The external popliteal, or peroneal nerve. 13, 13, The posterior tibial nerve. 14, The external tibial nerve. 15, The muscular branch of the external peroneal nerve. 18, The muscular branch of the sciatic nerve. P, Q, The posterior tibial nerve. The letters and other figures indicate minor nervous filaments distributed to the various muscles and the skin. PLATE IX. THE SKIN. Fig. 1. _A perspiratory Tube and Gland._ 1, 1, The contorted portion of the tube that forms the gland. 2, 2, Two branches which unite to form the main duct of the gland. 3, 3, The perspiratory tube. 4, The cuticle. 5. Its colored portion. 6, The cutis vera, (true skin.) 7, 7, Fat vesicles, in which the gland is imbedded. Fig. 2. _A Papilla of the Skin._ 1, 1, Two papillæ, formed of an artery vein, and nerve. 2, 2, 2, 2, Nerves forming a loop in the papillæ. 3, 3, Arteries of the papillæ. 4, 4, Veins of the papillæ. 5, 5, A net-work of arteries, veins, and nerves. 6, 6, Nerves of the skin. 8, 8, Arteries of the skin. 7, 7, Veins of the skin. Fig. 3. _A Hair, and its Oil-Glands._ 1, 1, The hair. 2, 2, The sheath of the hair. 3, Oil-glands that surround the bulb of the hair, the ducts of which open into the sheath of the hair, (2, 2.) Fig. 4. _A Section of the Skin._ 1, 1, The cuticle. 2, 2, Its colored portion. 3, 3, The papillary layer. 4, 4, A net-work of arteries, veins, and nerves, upon the upper surface of the cutis vera. 5, 5, 5, 5, The cutis vera, (true skin.) 6, 6, 6, Hairs that originate in the cutis vera. 7, 7, 7, Oil-glands, the ducts of which connect with the sheath of the hair. 8, 8, 8, 8, 8, 8, 8, 8, Perspiratory glands and their ducts. 9, 9, 9, 9, 9, Nerves of the skin 10, 10, 10, 10, 10, Arteries of the skin. 11, 11, 11, 11, 11, Veins of the skin. 12, 12, 12, 12, Papillæ, or ridges of the skin. PLATE X. AN ANTERO-POSTERIOR SECTION OF THE EYE. Fig. 1. 1, 1, The sclerotic coat. 2, 2, The cornea. 3, 3, The choroid coat. 4, 4, The retina. 5, 5, The iris. 6, 6, The posterior chamber of the eye that contains the aqueous humor. 7, 7, The anterior chamber. 8, 8, The pupil. 9, The crystalline humor. 10, 10, The vitreous humor 11, The optic nerve. 12, A representation of a pen. 13, An inverted image of the pen (12) on the retina. 14, 14, A canal surrounding the crystalline humor. 15, 15, The bevelled junction of the cornea and sclerotic coats. A, a perpendicular ray of light from the pen. B, B, oblique rays, that are refracted in passing through the humors of the eye. Fig. 2. _A View of the External, Middle, and Internal Ear._ 1, 1, The external ear. 2, The meatus auditorius externus, (the tube that connects with the middle ear.) 3. The membrana tympani, (drum of the ear.) 8, 8, The tympanum, (middle ear.) 4, The malleus. 5, The incus. 6, The orbicularis. 7, The stapes, (stirrup-bone,) that connects with the vestibule of the internal ear. 9, 9, (4, 5, 6, 7, The small bones of the middle ear,) 10, 11, 12, The semicircular canals. 13, 13, The cochlea. 14, The auditory nerve. 15, The division of the auditory nerve to the semicircular canals. 16, The division to the cochlea. 17, 17, The Eustachian tube. 18, The chorda tympani nerve. 19, The seventh pair (facial) nerve. 20, The styloid process of the temporal bone. 21, 21, 21, 21, 21, The petrous or hard portion of the temporal bone, in which the parts of the middle and internal ear are situated. * * * * * * * * * * * * * * Below is given the Title of a Book on a new plan, just published, intended for beginners in the study of Physiology. * * * * * HUMAN AND COMPARATIVE ANATOMY, PHYSIOLOGY, AND HYGIENE BY MRS. EUNICE P. CUTTER. WITH ONE HUNDRED ENGRAVINGS. NEW YORK: CLARK, AUSTIN, AND SMITH 3 PARK ROW TEXT BOOKS UPON =Anatomy, Physiology, and Hygiene.= Recommended by the Hon. N. W. EDWARDS, School Sup't, Ill. HUMAN AND COMPARATIVE ANATOMY, PHYSIOLOGY, AND HYGIENE. For District Schools. With 100 Engravings. 132 pages. By MRS. EUNICE P. CUTTER. Price 33 cts. This work contains full directions for the _study_ and _teaching_ of Anatomy, Physiology, and Hygiene. This is a new feature. _Every teacher would profit by it._ The plan of the work can be gathered from the following _fac-simile_ of the table of contents:-- [Illustration: Fac-simile of the table of contents] * * * * * Transcriber's note: Typographical problems have been changed and are listed below. Author's archaic and variable spelling is mostly preserved. Author's punctuation style is mostly preserved. Passages in italics indicated by _underscores_. Passages in bold indicated by =equal signs=. In paragraph 97, '[s]' is used to represent the integral symbol. Greek words and letters have been transliterated and placed between +marks+. This transcription is faithful to the original transliterations of Greek (which occur in italics), even when they seem incorrect. Author's Greek transliterations included vowels with macrons. These macrons have been changed to circumflexes in order to display correctly in this text transcription. The original revision questions at the bottom of each page have been set between lines that look like '-=-=-=-=-=-=-=-=-=-=-=-='. Footnotes have been placed directly below their relevant paragraphs. Transcriber's changes: Title page: Was 'DESIGNER' (=DESIGNED= FOR) Title page: Was 'Massachuetts' (In the Clerk's Office of the District Court of the District of =Massachusetts=.) Title page: Added '.' (No. 15 Vandewater Street, N. =Y.=) Page 18: Added ',' (_Example._ The digestive apparatus consists of the =teeth,= stomach, liver, &c., all of which aid in the digestion of food.) Page 23, Fig. 5: Added '.' (=Fig.= 5. A section of the femur, (thigh-bone.) 1, 1, The extremities, showing a thin plate of compact texture) Page 24: Was 'serious' (40. How does the mucous differ from the =serous= tissue? What is the appearance of the external surface of this membrane?) Page 27: Added comma (The most important compounds are _Al-bu´men_, =_Fi´brin_,= _Gel´a-tin_) Page 27: Was 'organ ized (57. What are proximate elements? Do they exist already formed in =organized= bodies? Name the most important compounds.) Page 29: Added '.' (The earthy portion of the bones gives them solidity and strength, while the animal part endows them with =vitality.=) Page 33, Fig. 7: Added '.' (=7.= 1, 1, The coronal suture at the front and upper part of the skull, or) Page 33, Fig. 7: Was 'cra nium' over line break. (suture at the front and upper part of the skull, or =cranium=. 2, The sagittal suture on the top of the skull.) Page 35, Fig. 9: Added '.' (=Fig.= 9. 1, The first bone of the sternum, (breast-bone.) 2. The second bone of the sternum.) Page 36: Added '.' (83. Describe the thorax. Explain fig. 9. 84. Describe the =sternum.= 85. Describe the ribs.) Page 36: Added '?' (88. Give the structure of the vertebra. Where is the spinal cord placed? 89. What is placed between each =vertebra?= What is its use?) Page 37, Fig 10: Added '.' (5, The transverse =process.= 7, The inferior articulating process.) Page 38, Fig 12: Added '.' (2, The sacrum. 3, The =coccyx.= 4, 4, The acetabulum. a, a, The pubic portion) Page 38: Added '.' (In the adult? Describe the acetabulum. 93. Describe the =sacrum.= Explain fig. 12. 94. Describe the coccyx.) Page 41: Was 'out side' over page break (101. The RADIUS articulates with the bones of the carpus and forms the wrist-joint. This bone is situated on the =outside= of the fore-arm) Page 41, Fig. 16: Added '.' (11, 11, First range of finger-bones. 12, 12, Second range of finger-bones. 13, 13, Third range of =finger-bones.= 14, 15, Bones of the thumb.) Page 42: Was 'meta carpal' over line break. (and upon the other, the first bone of the thumb. The five =metacarpal= bones articulate with the second range of carpal bones.) Page 42: Added '.' (101. The radius. 102. How many bones in the carpus? How are they ranged? =103.= Describe the) Page 42: Added '.' (103. Describe the =metacarpus.=) Page 42: Was 'sim ilar' over line break. (109. The FIBULA is a smaller bone than the tibia, but of =similar= shape. It is firmly bound to the tibia, at each extremity.) Page 43, Fig. 17: Added '.' (=Fig.= 17. 1, The shaft of the femur, (thigh-bone.)) Page 44: Was 'a' (They articulate at one extremity with one range of tarsal bones; =at= the other extremity, with the first range of the toe-bones.) Page 45, Fig. 21: Added '.' (Fig. 21 The relative position of the bones, cartilages, and synovial =membrane.= 1, 1, The extremities of two bones that concur to form a joint.) Page 46: Added '.' (112. Describe the phalanges. 113-118. _Give the anatomy of the =joints.=_ 113. What is said of the joints? Of what are the joints composed?) Page 46: Added '?' (112. Describe the phalanges. 113-118. _Give the anatomy of the joints._ 113. What is said of the joints? Of what are the joints =composed?=) Page 52, Fig. 28: Added '.' (14, The hand. 15, The haunch-bone. 16, The =sacrum.= 17, The hip-joint.) Page 52, Fig. 28: Added '.' (19, The patella. 20, The =knee-joint.= 21, The fibula. 22, The tibia.) Page 65: Added '.' (150-160. _Give the anatomy of the =muscles.=_ 150. What is said of the muscles? 151. Give their structure.) Page 70, Fig. 39: Added '.' (Fig. =39.= A front view of the muscles of the trunk.) Page 70, Fig. 39: Was 'superficia' (On the left side the =superficial= layer is seen; on the right, the deep layer. 1, The pectoralis major muscle.) Page 72, Fig. 41: Added '.' (Fig. 41 The first, second, and part of the third layer of muscles of the =back.= The first layer is shown on the right, and the second on the left side.) Page 72, Fig. 41: Added '.' (_Practical Explanation._ The muscles 1, 11, 12, draw the scapula back toward the =spine.= The muscles 11, 12, draw the scapula upward toward the head) Page 73, Fig. 42: Added '.' (Fig. 42. A representation of the under, or abdominal side of the =diaphragm.= 1, 2, 3, 4, The portion which is attached to the margin of the ribs.) Page 74, Fig. 43: Added '.' (=Fig.= 43. A front view of the superficial layer of muscles of the fore-arm. 5, The flexor carpi radialis muscle.) Page 74: Added '.' (That perform the delicate movements of the fingers? Give the use of some of the muscles represented by =fig.= 43. Those represented by fig. 44.) Page 81: Added '.' (The ball and socket joints, as the shoulder, are not limited to mere flexion and =extension.= No joint in the system has the range of movement that is) Page 84, Fig. 47: Added '.' (The muscles 9, fig. 46, and 6, =fig.= 47, bend the neck forward. The muscles 3, 4, fig. 47, elevate the head and chin.) Page 84, Fig. 47: Added '.' (The muscles 26, 27, 28, fig. 46, bend the lower limbs on the body, at the =hip.= The muscle 28, fig. 46, draws one leg over the other) Page 84, Fig. 47: Added '.' (The muscles 27, 28, =fig.= 47, extend the lower limbs on the body, at the hip. The muscles 29, 30, 31, fig. 46, extend the leg at the knee.) Page 84, Fig. 47: Added ',' (The muscles 27, 28, fig. =47,= extend the lower limbs on the body, at the hip. The muscles 29, 30, 31, fig. 46, extend the leg at the knee.) Page 84, Fig. 47: Added '.' (The muscles 27, 28, fig. 47, extend the lower limbs on the body, at the =hip.= The muscles 29, 30, 31, fig. 46, extend the leg at the knee.) Page 84, Fig. 47: Added '.' (The muscles 29, 30, fig. =47,= bend the leg at the knee. The muscles 34, 36, fig. 46, bend the foot at the ankle, and extend the toes.) Page 88: Added '?' (What class of pupils should have recesses most =frequently?= 179. What effect has continued muscular contraction?) Page 95: Added '.' (196. Give an instance of the different effects produced by the absence and presence of the mental =stimulus.=) Page 97, Fig. 49: Was '(1.' (the unnatural curved spinal column, and its relative position to the perpendicular, =1.= The lower limbs are curved at the knee) Page 98: Added comma. (In performing any labor, as in speaking, reading, singing, mowing, sewing, =&c.,= there will be less exhaustion) Page 100, Fig. 51: Added '.' (Fig. 51. An improper position in =sitting.=) Page 104: Added ',' (210. What is said of the lateral and oblique movements of the =arm,= hand, and fingers in writing? How is this shown by experiment?) Page 107, Fig. 55: Added '.' (_d_, _e_, The bicuspids. _f_, _g_, The molars, (double teeth.) _h_, The wisdom =teeth.=) Page 108, Fig. 56: Added '.' (=Fig.= 56. A side view of the body and enamel of a front tooth.) Page 108, Fig. 57: Added '.' (=Fig.= 57. A side view of a molar tooth. 1, The enamel. 2, The body of the tooth.) Page 108, Fig. 57: Added '.' (1, The enamel. 2, The body of the =tooth.= 3, The cavity in the crown of the tooth that contains the pulp.) Page 115, Fig. 59: Added '.' (=Fig.= 59. A side view of the face, oesophagus, and trachea.) Page 118: Was 'COECUM' (249. The =C�CUM= is the blind pouch, or cul-de-sac, at the commencement of the large intestine. Attached to its extremity) Page 119: Was 'coecum' (is the mucous membrane sometimes called the villous coat? 249. Describe the =cæcum=.) Page 119, Fig. 61: Was 'coecum' (4, The appendix vermiformis. 5, The =cæcum=. 6, The ascending colon. 7, The transverse colon.) Page 120: Was 'coecum' (half shorter than the intestine, and give it a sacculated appearance, which is characteristic of the =cæcum= and colon.) Page 127: Moved up from the following box. (What is said in regard to the bile? 266. What becomes of the chyle? =Of the residuum?=) Page 128, Fig. 65: Added '.' (Fig. 65. An ideal view of the organs of digestion, opened nearly the whole =length.=) Page 128, Fig. 65: Added '.' (1, The upper jaw. 2, The lower jaw. 3, The tongue. 4, The roof of the =mouth.= 5, The oesophagus. 6, The trachea. 7, The parotid gland.) Page 128, Fig. 65: Added '.' (8, The sublingual =gland.= 9, The stomach. 10, 10, The liver. 11, The gall-cyst.) Page 128, Fig. 65: Added ',' (16, The opening of the small intestine into the large intestine. 17, 18, 19, =20,= The large intestine. 21, The spleen.) Page 128, Fig. 65: Added '.' (16, The opening of the small intestine into the large intestine. 17, 18, 19, 20, The large =intestine.= 21, The spleen.) Page 128, Fig. 65: Added '.' (21, The spleen. 22, The upper part of the spinal =column.=) Page 129: Was 'prope' (The food that is well masticated, and has blended with it a =proper= amount of saliva, will induce a healthy action in the stomach.) Page 129: Added '.' (will induce a healthy action in the =stomach.= Well-prepared chyme is the natural stimulus of the duodenum,) Page 129: Added ',' (Well-prepared chyme is the natural stimulus of the =duodenum,= liver, and pancreas; pure chyle is the appropriate excitant of) Page 131: Added '.' (another demand for food. What effect has increased exercise upon the system? =278.= How are the new particles of matter supplied? What does this induce?) Page 143: Was 'There fore' over line break. (digested becomes mixed with that last taken. =Therefore= the interval between each meal should be) Page 145: Added '.' (312. Why should they not be taken cold? Show some of the effects of improper food upon the inferior =animals.=) Page 153: Added '.' (=327.= Why does the position of a person affect digestion? 328. Into what are different kinds of aliment separated?) Page 154: Added ',' (333. The CIRCULATORY ORGANS are the _Heart_, =_Ar´te-ries_,= _Veins_, and _Cap´il-la-ries_.) Page 170, Fig. 75: Added '.' (=Fig.= 75. An ideal view of the circulation in the lungs and system. From the right ventricle of the heart) Page 179: Added '.' (the proper method of arresting the flow of blood from divided arteries. 382. The second incident. =383.= How should "flesh wounds" be dressed?) Page 182: Added '.' (What other vessels perform the office of absorption? Give observation. 389. Describe the =lymphatics.=) Page 186, Fig. 85: Added '.' (16, 17, 18, Of the face and neck. 19, 20, Large =veins.= 21, The thoracic duct. 26, The lymphatics of the heart.) Page 189: Added '.' (matter formed in the system of the diseased person, may be more readily conveyed into their =own.=) Page 191: Was 'gen eral' over line. (every trifling and temporary enlargement, or tumor, is a cancer. Their =general= remedy is arsenic; and happy is the unfortunate sufferer) Page 191: Was 'suf ferer' over line. (arsenic; and happy is the unfortunate =sufferer= who escapes destruction in their hands, for too frequently) Page 191: Was 'frequent ly' over line. (happy is the unfortunate sufferer who escapes destruction in their hands, for too =frequently= their speedy cure is death.) Page 191: Was 'imme diately' over line. (413. In case of an accidental wound, it is best =immediately= to bathe the part thoroughly in pure water, and to) Page 192: Was 'Fol li-cles' (415. The SECRETORY ORGANS are the _Ex-ha´lants_, =_Fol´li-cles_=, and the _Glands_.) Page 192, Fig. 86: Added '.' (Fig. 86. A secretory follicle. An artery is seen, which supplies the material for its =secretion.= Follicles are also supplied) Page 193: Was 'mys terious' over line. (420. SECRETION is one of the most obscure and =mysterious= functions of the animal economy. "It is that process) Page 194: Was 'secre tion' over line. (420-431. _Give the physiology of the secretory organs._ 420. What is =secretion=?) Page 202: Was 'he' (Very soon, minute vessels shoot out from the living parts into =the= coagulum of the blood, and immediately commence their operations) Page 207: Added '?' (461. Mention another means by which the blood may be made impure. How =remedied?= 462. What is the effect of want of cleanliness upon the blood?) Page 208, Fig. 88: Added '.' (7, The right auricle of the heart. 8, The left auricle. 9, The pulmonary artery. 10, The aorta. 11, The vena cava =descendens.= 12, The trachea.) Page 208, Fig. 88: Added '.' (16, 16, The right and left lobe of the liver. 17, The gall-cyst. 18, The =stomach.= 26, The spleen. 19, 19, The duodenum.) Page 208, Fig. 88: Added '.' (19, 19, The duodenum. 20, The ascending =colon.= 21, The transverse colon. 25, The descending colon.) Page 211, Fig. 90: Added '.' (10, Its lower lobe. 11, The upper lobe of the right =lung.= 12, The middle lobe. 13, The lower lobe.) Page 218: Was 'cavicle' (Those which are attached to the upper rib, sternum, and =clavicle=, contract and elevate the lower and free extremities of the ribs.) Page 220, Fig. 96: Added '.' (5, 5, The position of the walls of the abdomen in inspiration. 6, 6, The position of the abdominal walls in =expiration.=) Page 223: Was 'cabonic' (In addition, there is a small amount of vapor of water and =carbonic= acid. The pressure of this invisible) Page 225, Fig. 98: Added '.' (Fig. 98. 1, A bronchial tube divided into three branches. 2, 2, 2, =Air-cells.= 3, Branches of the pulmonary artery, that spread over the air-cells.) Page 226: Added 'to' (In a few hours, the blood next =to= the membrane will have become of a bright red color.) Page 227: Added '.' (reviewed from figs. 96, 97, and 99, or from anatomical outline plates Nos. 5 and =7.=) Page 232: Added '.' (503. Mention some reasons why different persons do not require the same amount of =air.=) Page 232: Added '.' (Give the illustration of the effects of impure air on lighted =lamps.=) Page 237: Added '.' (to connect with the outer walls of the building or external =air.= But if pure heated air is introduced into the room, it obviates) Page 241: Added '.' (What does fig. 100 represent? Fig. 101? Give observation =1st.=) Page 248: Added '.' (535. Mention some of the effects of mental depression upon the =body.= What is related by Lænnec?) Page 250: Was single-quote (Let another person press upon the projecting part of the neck, called "Adam's =apple,"= while air is introduced into the lungs through the bellows.) Page 263: Changed '.' to '?' (persons that have broad chests and voluminous lungs suffer less from cold than the narrow-chested with small =lungs?=) Page 269: Added '.' (still broader behind, where it is connected with the thyroid =cartilage.= Below, it connects with the first ring of the trachea.) Page 271: Was 'glot tis' (The aperture, or opening between these ligaments, is called the =_glot´tis_=, or _chink of the glottis_.) Page 276: Added '.' (vocal organs are in action, will induce too great a flow of blood to these parts, which will be attended by subsequent =debility.=) Page 289, Fig. 115: Added '.' (These ducts open into the sheath of the hair, (B.) All the figures, from 1 to 4, are magnified thirty-eight =diameters.=) Page 294: Added ';' (A proper thickness of the cuticle is in this manner =preserved;= the faculty of sensation and that of touch are properly regulated;) Page 326: Added '?' (What causes the edge of the nail "to grow into the flesh" of the =toe?= How prevented?) Page 329: Added '.' (731. What does the term brain designate? Name =them.= How are they protected? Describe fig. 120.) Page 330, Fig. 121: Added '.' (Fig. =121.= A section of the skull-bones and cerebrum. 1, 1, The skull.) Page 330, Fig. 121: Added '.' (1, 1, The skull. 2, 2, the dura =mater.= 3, 3, The cineritious portion of the cerebrum.) Page 330, Fig. 121: Added '.' (3, 3, The cineritious portion of the cerebrum. 4, 4, The medullary =portion.= The dark points indicate the position of divided blood-vessels.) Page 332: Added '.' (=733.= Describe the appearance of the brain when a horizontal section has been made. What is the gray border often called? What connects the) Page 333, Fig. 123: Added '.' (4, 4, The optic foramen in the sphenoid bone; through which passes the second pair of =nerves.= 5, 5, The sphenoidal fissure.) Page 334, Fig. 124: Added '.' (5, The corpus callosum. 6, The first pair of nerves. 7, The second =pair.= 8, The eye. 9, The third pair of nerves.) Page 334: Added '.' (738. Describe the dura mater. What is its use? Explain =fig.= 124.) Page 342: Added '.' (758. How many pairs of nerves issue from the spinal cord? Explain =fig.= 128. Fig. 129.) Page 347: Was '13 1-2' (The heaviest brain on record was that of Cuvier, which weighed 4 pounds and =13½= ounces.) Page 365: Added '.' (what age particularly is excessive and continued mental exertion hurtful? =813.= What is said of scrofulous and rickety children?) Page 369: Added '.' (the more repose they =require.= The organs of the child, beside sustaining their proper functions,) Page 385: Added '.' (868. What is the appearance of the surface of the tongue? Explain =fig.= 134.) Page 387: Added '.' (papillæ. 870. The fungiform papillæ? What nerve ramifies in the fungiform papillæ? How can these papillæ, or points, be seen? =871-875.= _Give the physiology of the organs of taste._ 871. Define taste.) Page 394: Added '.' (=892.= Describe the optic nerve. 893. Describe the globe of the eye.) Page 394: Added '.' (892. Describe the optic =nerve.= 893. Describe the globe of the eye.) Page 395, Fig. 137: Added '.' (7, 8, 9, 10, 11, 12, 13, The origin of several pairs of cranial =nerves.=) Page 396: Added '.' (In form, it is circular, convexo-concave, and resembles a =watch-glass.= It is received by its edge, which is sharp and thin, within the) Page 397, Fig. 138: Added '.' (a transverse section of the globe of the eye, seen from =within.= 1, The divided edge of the three coats--sclerotic) Page 399, Fig. 139: Added '.' (The cornea (This connects with the sclerotic coat by a bevelled edge.) 3, The choroid =coat.= 6, 6, The iris. 7, The pupil.) Page 401: Added ',' (906. The PROTECTING ORGANS are the _Or´bits_, =_Eyebrows_,= _Eyelids_, and _Lach´ry-mal Apparatus_.) Page 401: Added '.' (covered with short, thick hairs, which form the upper boundary of the =orbits.= The eyebrows are so arranged) Page 401: Added '.' (909. Describe the =eyelids.= What is the use of the conjunctiva? How are the white spots frequently) Page 403: Added '.' (913. Describe the lachrymal =gland.= How many ducts pass from this gland, and what do they convey to the) Footnote 22: Added '.' (The refracting character of differently-formed lenses is illustrated in the works on Natural Philosophy, to which the pupil is =referred.=) Page 407, Fig. 142: Added '.' (Fig. 142. The forms of the different lenses. 1, A plane lens. 2, A globe =lens.= 3, A convexo-convex lens. 4, A plano-convex lens.) Page 407, Fig. 142: Added '.' (4, A plano-convex lens. 5, A concavo-concave =lens.= 6, A plano-concave lens. 7, Meniscus. 8, A concavo-convex lens.) Page 416: Changed '.' to '?' (Where is the wax of the ear =secreted?= 948. Describe the membrana tympani.) Page 417: Was ', 1,' (This figure is highly magnified. =1, 1,= The cochlea. 2, 3, Two channels, that wind two and a half turns around a central point) Page 421: Was 'Eustuchian' (This is the result of the air in the middle ear escaping through the =Eustachian= tube, when the vibrations of the membrana tympani are violent.) Page 422: Added '.' (969. Many of the parts just enumerated aid in hearing, but are not absolutely essential to this =sense.= But if the vestibule) Page 422: Added '.' (_Note._ Let the anatomy and physiology of the organs of hearing be reviewed, from fig. 148, or from anatomical outline plate No. =10.=) Page 439: Added '.' (know the proper mode of procedure in such cases, in order to render immediate assistance when within his =power.=) Page 441: Added '.' (=1035.= What is the antidote? 1036. What should immediately be done when arsenic is swallowed?) Page 441: Changed '.' to '?' (When magnesia cannot be obtained, what will answer as a =substitute?= 1050. What is the antidote when ley is swallowed?) Page 442: Changed '.' to '?' (What treatment should be adopted when an over-dose of opium or any of its preparations is =taken?= 1057. What is said of stramonium?) Page 443: Added '.' (lobelia, bloodroot, tobacco, &c., is taken? =1062.= Should a physician be called in all cases when poison is swallowed?) Page 444: Added '.' (CASEINE is abundantly found in milk. When dried, it constitutes =cheese.= Alcohol, acids, and the stomach of any of the mammalia coagulate it; and) Page 444: Added '.' (canal pass slowly through this portion. The _rectum_ is named from the straight direction that it assumes in the latter part of its =course.=) Page 445: Was 'a' (This is called the peristaltic, or vermicular motion. The great length of intestine in =all= animals, and especially in the herbivorous ones, is owing to the necessity of) Page 448: Added '.' (and often inspiring more deeply than is common in older =persons.= Also, if the carbon of the food does not have a requisite supply of oxygen) Page 451: Added '.' (=AB-DUC´TOR.= [L. _abduco_ to lead away.] A muscle which moves certain parts,) Page 452: Original looks like 'Arbør'. (AR´BOR. [L.] A tree. _=Arbor= vitæ._ The tree of life. A term applied to a part) Page 452: Added ',' (BRE´VIS. [L.] _Brevis_, short; =_brevior_,= shorter.) Page 452: Added ']' (CAP´IL-LA-RY. [L. _capillus_, a =hair.]= Resembling a hair; small.) Page 454: Added '.' (Having the quality of exhaling or =evaporating.=) Page 457: Added '.' (MI´TRAL. [=L.= _mitra_, a mitre.] The name of the valves in the left side of) Page 458: Added '.' (=O-MEN´TUM.= [L.] The caul.) Page 458: Added '.' (=OP-PO´NENS.= That which acts in opposition to something. The name of two) Page 458: Added '.' (OX-AL´IC. Pertaining to sorrel. _Oxalic acid_ is the acid of =sorrel.= It is composed of two equivalents of carbon) Page 458: Added '.' (invisible and inodorous. One of the components of atmospheric =air.=) Page 458: Added '.' (PEC´TUS. [L.] The =chest.=) Page 458: Added '.' (PEC´TO-RAL. Pertaining to the =chest.=) Page 459: Added '.' (PLEX´US, [L. _plecto_, to weave =together.=] Any union of nerves, vessels, or fibres,) Page 459: Added '.' (POS´TI-CUS. [L.] Behind; =posterior.= A term applied to certain muscles.) Page 459: Added '.' (The muscle of the forearm that moves the palm of the hand =downward.=) Page 460: Added '.' (=RA-DI-A´LIS.= Radial; belonging to the radius.) Page 460: Added '.' (RA´MUS. [L.] A branch. A term applied to the projections of =bones.=) Page 460: Added '.' (=SEP´TUM.= [L.] A membrane that divides two cavities from each other.) Page 462: Was 'Be longing' over line. (VIT´RE-OUS. [L. _vitrum_, glass.] =Belonging= to glass. A humor of the eye.) Page 462: Removed comma: was 'L.,' (VO´MER. [=L.= a ploughshare.] One of the bones of the nose.) Page 464: Added ',' (=----,= Physiology of the, 164) Page 464: Added ',' (=----,= Hygiene of the, 172) Page 464: Added ',' (----, Influence =of,= on the Circulation, 173) Page 465: Added ',' (=MEDIASTINUM,= 211) Page 465: Added ',' (MEDULLA =OBLONGATA,= 333) Page 466: Added ',' (PRESERVATION OF =HEALTH,= 425) Page 466: Substituted 'Spinal' for the repeat line. (=SPINAL= CORD, 36, 340) Page 467: Added comma (_Bones of the Head._ 7, The sphenoid bone. =8,= The frontal bone. 10, The parietal bone. 11, The os unguis. 12, The superior maxillary bone,) Page 468: Added ',' (41, 41, The bones of the =metatarsus,= (middle of the foot.) 42, 42, The bones of the toes.) Page 469: Added '.' (27, 28, Ligaments that connect the clavicle and =scapula.= 29, The capsular ligament of the shoulder-joint.) Page 469: Added '.' (9, Tendon of the gluteus =muscle.= 35, The capsular ligament of the hip-joint.) Page 469: Added '.' (37, The ligament that connects the tibia and =fibula.= 38, The interosseous ligament.) Page 469: Added '.' (38, The interosseous ligament. 39, 40, Ligaments of the =ankle-joint.=) Page 469: Added '.' (PLATE =III.=) Page 469: Added '.' (_Muscles of the Head and Neck._ 7, The sterno-mastoideus =muscle.= 8, The sterno-hyoideus muscle. 9, The omo-hyoideus muscle. 10, The) Page 469: Added '.' (16, The zygomatic muscle. 17, The depressor of the lower =lip.= 18, The depressor anguli oris muscle. 19, The triangular muscle of the) Page 469: Added '.' (43, The sartorius muscle. 44, The rectus femoris muscle. 45, The vastus externus =muscle.= 46, The vastus internus muscle.) Page 469: Added '.' (46, The vastus internus muscle. 47, The internal straight =muscle.= 48. The pectineus muscle. 49, The adductor muscle. 50, The psoas muscle.) Page 470: Added '.' (56, 57, The gastrocnemii muscles. 58, The long flexor muscle of the great =toe.= 69, The short extensor muscles of the toes.) Page 470: Added '.' (_Muscles of the Lower Extremities._ 29, The gluteus maximus =muscle.= 30, The gluteus medius muscle. 31, The biceps flexor cruris muscle.) Page 471: Added '.' (10, The pharynx. 11, The =oesophagus.= 12, The upper portion of the spinal column. C, The spinal cord.) Page 471: Added '.' (1, 1, 1, An outline of the right lung. 2, 2, 2, An outline of the left =lung.= 3, The larynx. 4, The trachea.) Page 472: Added '.' (_Arteries of the Neck and =Head.=_ 15, The right carotid artery. 16, The left carotid artery.) Page 472: Added '.' (The capillary vessels of the =lungs.= P, P, P, The right pulmonary vein. Q, Q, The left pulmonary vein.) Page 473: Unclear in original (10, The median nerve. G, The =circumvex= nerve of the shoulder.) Page 474: Added ',' (8, 8, =8,= 8, 8, 8, 8, 8, Perspiratory glands and their ducts. 9, 9, 9, 9, 9, Nerves of the) Page 475: Added '.' (8, 8, The tympanum, (middle ear.) 4, The =malleus.= 5, The incus. 6, The orbicularis.) 
15707	----	ZOONOMIA; OR, THE LAWS OF ORGANIC LIFE. VOL. I. _By ERASMUS DARWIN, M.D. F.R.S._ AUTHOR OF THE BOTANIC GARDEN. * * * * * Principiò coelum, ac terras, camposque liquentes, Lucentemque globum lunæ, titaniaque astra, Spiritus intùs alit, totamque infusa per artus Mens agitat molem, et magno se corpore miscet.--VIRG. Æn. vi. Earth, on whose lap a thousand nations tread, And Ocean, brooding his prolific bed, Night's changeful orb, blue pole, and silvery zones, Where other worlds encircle other suns, One Mind inhabits, one diffusive Soul Wields the large limbs, and mingles with the whole. * * * * * _THE SECOND EDITION, CORRECTED._ * * * * * LONDON: PRINTED FOR. J. JOHNSON, IN ST. PAUL'S CHURCH-YARD. 1796. Entered at Stationers' Hall. * * * * * DEDICATION. To the candid and ingenious Members of the College of Physicians, of the Royal Philosophical Society, of the Two Universities, and to all those, who study the Operations of the Mind as a Science, or who practice Medicine as a Profession, the subsequent Work is, with great respect, inscribed by the Author, DERBY, May 1, 1794. CONTENTS. _Preface._ SECT. I. _Of Motion._ II. _Explanations and Definitions._ III. _The Motions of the Retina demonstrated by Experiments._ IV. _Laws of Animal Causation._ V. _Of the four Faculties or Motions of the Sensorium._ VI. _Of the four Classes of Fibrous Motions._ VII. _Of Irritative Motions._ VIII. _Of Sensitive Motions._ IX. _Of Voluntary Motions._ X. _Of Associate Motions._ XI. _Additional Observations on the Sensorial Powers._ XII. _Of Stimulus, Sensorial Exertion, and Fibrous Contraction._ XIII. _Of Vegetable Animation._ XIV. _Of the Production of Ideas._ XV. _Of the Classes of Ideas._ XVI. _Of Instinct._ XVII. _The Catenation of Animal Motions._ XVIII. _Of Sleep._ XIX. _Of Reverie._ XX. _Of Vertigo._ XXI. _Of Drunkenness._ XXII. _Of Propensity to Motion. Repetition. Imitation._ XXIII. _Of the Circulatory System._ XXIV. _Of the Secretion of Saliva, and of Tears. And of the Lacrymal Sack._ XXV. _Of the Stomach and Intestines._ XXVI. _Of the Capillary Glands, and of the Membranes._ XXVII. _Of Hemorrhages._ XXVIII. _The Paralysis of the Lacteals._ XXIX. _The Retrograde Motions of the Absorbent Vessels._ XXX. _The Paralysis of the Liver._ XXXI. _Of Temperaments._ XXXII. _Diseases of Irritation._ XXXIII. ---- _of Sensation._ XXXIV. ---- _of Volition._ XXXV. ---- _of Relation._ XXXVI. _The Periods of Diseases._ XXXVII. _Of Digestion, Secretion, Nutrition._ XXXVIII. _Of the Oxygenation of the Blood in the Lungs and Placenta._ XXXIX. _Of Generation._ XL. _Of Ocular Spectra._ * * * * * TO ERASMUS DARWIN, ON HIS WORK INTITLED ZOONOMIA, _By DEWHURST BILSBORROW._ * * * * * HAIL TO THE BARD! who sung, from Chaos hurl'd How suns and planets form'd the whirling world; How sphere on sphere Earth's hidden strata bend, And caves of rock her central fires defend; Where gems new-born their twinkling eyes unfold, 5 And young ores shoot in arborescent gold. How the fair Flower, by Zephyr woo'd, unfurls Its panting leaves, and waves its azure curls; Or spreads in gay undress its lucid form To meet the sun, and shuts it to the storm; 10 While in green veins impassion'd eddies move, And Beauty kindles into life and love. How the first embryon-fibre, sphere, or cube, Lives in new forms,--a line,--a ring,--a tube; Closed in the womb with limbs unfinish'd laves, 15 Sips with rude mouth the salutary waves; Seeks round its cell the sanguine streams, that pass, And drinks with crimson gills the vital gas; Weaves with soft threads the blue meandering vein, The heart's red concave, and the silver brain; 20 Leads the long nerve, expands the impatient sense, And clothes in silken skin the nascent Ens. Erewhile, emerging from its liquid bed, It lifts in gelid air its nodding head; The lights first dawn with trembling eyelid hails, 25 With lungs untaught arrests the balmy gales; Tries its new tongue in tones unknown, and hears The strange vibrations with unpractised ears; Seeks with spread hands the bosom's velvet orbs. With closing lips the milky fount absorbs; 30 And, as compress'd the dulcet streams distil, Drinks warmth and fragrance from the living rill;-- Eyes with mute rapture every waving line, Prints with adoring kiss the Paphian shrine, And learns erelong, the perfect form confess'd, 35 Ideal Beauty from its mother's breast. Now in strong lines, with bolder tints design'd, You sketch ideas, and portray the mind; Teach how fine atoms of impinging light To ceaseless change the visual sense excite; 40 While the bright lens collects the rays, that swerve, And bends their focus on the moving nerve. How thoughts to thoughts are link'd with viewless chains, Tribes leading tribes, and trains pursuing trains; With shadowy trident how Volition guides, 45 Surge after surge, his intellectual tides; Or, Queen of Sleep, Imagination roves With frantic Sorrows, or delirious Loves. Go on, O FRIEND! explore with eagle-eye; Where wrapp'd in night retiring Causes lie: 50 Trace their slight bands, their secret haunts betray, And give new wonders to the beam of day; Till, link by link with step aspiring trod, You climb from NATURE to the throne of GOD. --So saw the Patriarch with admiring eyes 55 From earth to heaven a golden ladder rise; Involv'd in clouds the mystic scale ascends, And brutes and angels crowd the distant ends. TRIN. COL. CAMBRIDGE, _Jan._ 1, 1794. * * * * * REFERENCES TO THE WORK. _Botanic Garden._ Part I. Line 1. Canto I. l. 105. ---- 3. ---- IV. l. 402. ---- 4. ---- I. l. 140. ---- 5. ---- III. l. 401. ---- 8. ---- IV. l. 452. ---- 9. ---- I. l. 14. _Zoonomia._ ---- 12. Sect. XIII. ---- 13. ---- XXXIX. 4. 1. ---- 18. ---- XVI. 2. and XXXVIII. ---- 26. ---- XVI. 4. ---- 30. ---- XVI. 4. ---- 36. ---- XVI. 6. ---- 38. ---- III. and VII. ---- 43. ---- X. ---- 44. ---- XVIII. 17. ---- 45. ---- XVII. 3. 7. ---- 47. ---- XVIII. 8. ---- 50. ---- XXXIX. 4. 8. ---- 51. ---- XXXIX the Motto. ---- 54. ---- XXXIX. 8. * * * * * PREFACE. * * * * * The purport of the following pages is an endeavour to reduce the facts belonging to ANIMAL LIFE into classes, orders, genera, and species; and, by comparing them with each other, to unravel the theory of diseases. It happened, perhaps unfortunately for the inquirers into the knowledge of diseases, that other sciences had received improvement previous to their own; whence, instead of comparing the properties belonging to animated nature with each other, they, idly ingenious, busied themselves in attempting to explain the laws of life by those of mechanism and chemistry; they considered the body as an hydraulic machine, and the fluids as passing through a series of chemical changes, forgetting that animation was its essential characteristic. The great CREATOR of all things has infinitely diversified the works of his hands, but has at the same time stamped a certain similitude on the features of nature, that demonstrates to us, that _the whole is one family of one parent_. On this similitude is founded all rational analogy; which, so long as it is concerned in comparing the essential properties of bodies, leads us to many and important discoveries; but when with licentious activity it links together objects, otherwise discordant, by some fanciful similitude; it may indeed collect ornaments for wit and poetry, but philosophy and truth recoil from its combinations. The want of a theory, deduced from such strict analogy, to conduct the practice of medicine is lamented by its professors; for, as a great number of unconnected facts are difficult to be acquired, and to be reasoned from, the art of medicine is in many instances less efficacious under the direction of its wisest practitioners; and by that busy crowd, who either boldly wade in darkness, or are led into endless error by the glare of false theory, it is daily practised to the destruction of thousands; add to this the unceasing injury which accrues to the public by the perpetual advertisements of pretended nostrums; the minds of the indolent become superstitiously fearful of diseases, which they do not labour under; and thus become the daily prey of some crafty empyric. A theory founded upon nature, that should bind together the scattered facts of medical knowledge, and converge into one point of view the laws of organic life, would thus on many accounts contribute to the interest of society. It would capacitate men of moderate abilities to practise the art of healing with real advantage to the public; it would enable every one of literary acquirements to distinguish the genuine disciples of medicine from those of boastful effrontery, or of wily address; and would teach mankind in some important situations the _knowledge of themselves_. There are some modern practitioners, who declaim against medical theory in general, not considering that to think is to theorize; and that no one can direct a method of cure to a person labouring under disease without thinking, that is, without theorizing; and happy therefore is the patient, whose physician possesses the best theory. The words idea, perception, sensation, recollection, suggestion, and association, are each of them used in this treatise in a more limited sense than in the writers of metaphysic. The author was in doubt, whether he should rather have substituted new words instead of them; but was at length of opinion, that new definitions of words already in use would be less burthensome to the memory of the reader. A great part of this work has lain by the writer above twenty years, as some of his friends can testify: he had hoped by frequent revision to have made it more worthy the acceptance of the public; this however his other perpetual occupations have in part prevented, and may continue to prevent, as long as he may be capable of revising it; he therefore begs of the candid reader to accept of it in its present state, and to excuse any inaccuracies of expression, or of conclusion, into which the intricacy of his subject, the general imperfection of language, or the frailty he has in common with other men, may have betrayed him; and from which he has not the vanity to believe this treatise to be exempt. * * * * * ZOONOMIA. * * * * * SECT. I. OF MOTION. The whole of nature may be supposed to consist of two essences or substances; one of which may be termed spirit, and the other matter. The former of these possesses the power to commence or produce motion, and the latter to receive and communicate it. So that motion, considered as a cause, immediately precedes every effect; and, considered as an effect, it immediately succeeds every cause. The MOTIONS OF MATTER may be divided into two kinds, primary and secondary. The secondary motions are those, which are given to or received from other matter in motion. Their laws have been successfully investigated by philosophers in their treatises on mechanic powers. These motions are distinguished by this circumstance, that the velocity multiplied into the quantity of matter of the body acted upon is equal to the velocity multiplied into the quantity of matter of the acting body. The primary motions of matter may be divided into three classes, those belonging to gravitation, to chemistry, and to life; and each class has its peculiar laws. Though these three classes include the motions of solid, liquid, and aerial bodies; there is nevertheless a fourth division of motions; I mean those of the supposed ethereal fluids of magnetism, electricity, heat, and light; whose properties are not so well investigated as to be classed with sufficient accuracy. _1st._ The gravitating motions include the annual and diurnal rotation of the earth and planets, the flux and reflux of the ocean, the descent of heavy bodies, and other phænomena of gravitation. The unparalleled sagacity of the great NEWTON has deduced the laws of this class of motions from the simple principle of the general attraction of matter. These motions are distinguished by their tendency to or from the centers of the sun or planets. _2d._ The chemical class of motions includes all the various appearances of chemistry. Many of the facts, which belong to these branches of science, are nicely ascertained, and elegantly classed; but their laws have not yet been developed from such simple principles as those above-mentioned; though it is probable, that they depend on the specific attractions belonging to the particles of bodies, or to the difference of the quantity of attraction belonging to the sides and angles of those particles. The chemical motions are distinguished by their being generally attended with an evident decomposition or new combination of the active materials. _3d._ The third class includes all the motions of the animal and vegetable world; as well those of the vessels, which circulate their juices, and of the muscles, which perform their locomotion, as those of the organs of sense, which constitute their ideas. This last class of motion is the subject of the following pages; which, though conscious of their many imperfections, I hope may give some pleasure to the patient reader, and contribute something to the knowledge and to the cure of diseases. * * * * * SECT. II. EXPLANATIONS AND DEFINITIONS. I. _Outline of the animal economy._--II. 1. _Of the sensorium._ 2. _Of the brain and nervous medulla._ 3. _A nerve._ 4. _A muscular fibre._ 5. _The immediate organs of sense._ 6. _The external organs of sense._ 7. _An idea or sensual motion._ 8. _Perception._ 9. _Sensation._ 10. _Recollection and suggestion._ 11. _Habit, causation, association, catenation._ 12. _Reflex ideas._ 13. _Stimulus defined._ * * * * * As some explanations and definitions will be necessary in the prosecution of the work, the reader is troubled with them in this place, and is intreated to keep them in his mind as he proceeds, and to take them for granted, till an apt opportunity occurs to evince their truth; to which I shall premise a very short outline of the animal economy. * * * * * I.--1. The nervous system has its origin from the brain, and is distributed to every part of the body. Those nerves, which serve the senses, principally arise from that part of the brain, which is lodged in the head; and those, which serve the purposes of muscular motion, principally arise from that part of the brain, which is lodged in the neck and back, and which is erroneously called the spinal marrow. The ultimate fibrils of these nerves terminate in the immediate organs of sense and muscular fibres, and if a ligature be put on any part of their passage from the head or spine, all motion and perception cease in the parts beneath the ligature. 2. The longitudinal muscular fibres compose the locomotive muscles, whose contractions move the bones of the limbs and trunk, to which their extremities are attached. The annular or spiral muscular fibres compose the vascular muscles, which constitute the intestinal canal, the arteries, veins, glands, and absorbent vessels. 3. The immediate organs of sense, as the retina of the eye, probably consist of moving fibrils, with a power of contraction similar to that of the larger muscles above described. 4. The cellular membrane consists of cells, which resemble those of a sponge, communicating with each other, and connecting together all the other parts of the body. 5. The arterial system consists of the aortal and the pulmonary artery, which are attended through their whole course with their correspondent veins. The pulmonary artery receives the blood from the right chamber of the heart, and carries it to the minute extensive ramifications of the lungs, where it is exposed to the action of the air on a surface equal to that of the whole external skin, through the thin moist coats of those vessels, which are spread on the air-cells, which constitute the minute terminal ramifications of the wind-pipe. Here the blood changes its colour from a dark red to a bright scarlet. It is then collected by the branches of the pulmonary vein, and conveyed to the left chamber of the heart. 6. The aorta is another large artery, which receives the blood from the left chamber of the heart, after it has been thus aerated in the lungs, and conveys it by ascending and descending branches to every other part of the system; the extremities of this artery terminate either in glands, as the salivary glands, lacrymal glands, &c. or in capillary vessels, which are probably less involuted glands; in these some fluid, as saliva, tears, perspiration, are separated from the blood; and the remainder of the blood is absorbed or drank up by branches of veins correspondent to the branches of the artery; which are furnished with valves to prevent its return; and is thus carried back, after having again changed its colour to a dark red, to the right chamber of the heart. The circulation of the blood in the liver differs from this general system; for the veins which drink up the refluent blood from those arteries, which are spread on the bowels and mesentery, unite into a trunk in the liver, and form a kind of artery, which is branched into the whole substance of the liver, and is called the vena portarum; and from which the bile is separated by the numerous hepatic glands, which constitute that viscus. 7. The glands may be divided into three systems, the convoluted glands, such as those above described, which separate bile, tears, saliva, &c. Secondly, the glands without convolution, as the capillary vessels, which unite the terminations of the arteries and veins; and separate both the mucus, which lubricates the cellular membrane, and the perspirable matter, which preserves the skin moist and flexible. And thirdly, the whole absorbent system, consisting of the lacteals, which open their mouths into the stomach and intestines, and of the lymphatics, which open their mouths on the external surface of the body, and on the internal linings of all the cells of the cellular membrane, and other cavities of the body. These lacteal and lymphatic vessels are furnished with numerous valves to prevent the return of the fluids, which they absorb, and terminate in glands, called lymphatic glands, and may hence be considered as long necks or mouths belonging to these glands. To these they convey the chyle and mucus, with a part of the perspirable matter, and atmospheric moisture; all which, after having passed through these glands, and having suffered some change in them, are carried forward into the blood, and supply perpetual nourishment to the system, or replace its hourly waste. 8. The stomach and intestinal canal have a constant vermicular motion, which carries forwards their contents, after the lacteals have drank up the chyle from them; and which is excited into action by the stimulus of the aliment we swallow, but which becomes occasionally inverted or retrograde, as in vomiting, and in the iliac passion. II. 1. The word _sensorium_ in the following pages is designed to express not only the medullary part of the brain, spinal marrow, nerves, organs of sense, and of the muscles; but also at the same time that living principle, or spirit of animation, which resides throughout the body, without being cognizable to our senses, except by its effects. The changes which occasionally take place in the sensorium, as during the exertions of volition, or the sensations of pleasure or pain, are termed _sensorial motions_. 2. The similarity of the texture of the brain to that of the pancreas, and some other glands of the body, has induced the inquirers into this subject to believe, that a fluid, perhaps much more subtile than the electric aura, is separated from the blood by that organ for the purposes of motion and sensation. When we recollect, that the electric fluid itself is actually accumulated and given out voluntarily by the torpedo and the gymnotus electricus, that an electric shock will frequently stimulate into motion a paralytic limb, and lastly that it needs no perceptible tubes to convey it, this opinion seems not without probability; and the singular figure of the brain and nervous system seems well adapted to distribute it over every part of the body. For the medullary substance of the brain not only occupies the cavities of the head and spine, but passes along the innumerable ramifications of the nerves to the various muscles and organs of sense. In these it lays aside its coverings, and is intermixed with the slender fibres, which constitute those muscles and organs of sense. Thus all these distant ramifications of the sensorium are united at one of their extremities, that is, in the head and spine; and thus these central parts of the sensorium constitute a communication between all the organs of sense and muscles. 3. A _nerve_ is a continuation of the medullary substance of the brain from the head or spine towards the other parts of the body, wrapped in its proper membrane. 4. The _muscular fibres_ are moving organs intermixed with that medullary substance, which is continued along the nerves, as mentioned above. They are indued with the power of contraction, and are again elongated either by antagonist muscles, by circulating fluids, or by elastic ligaments. So the muscles on one side of the forearm bend the fingers by means of their tendons, and those on the other side of the fore-arm extend them again. The arteries are distended by the circulating blood; and in the necks of quadrupeds there is a strong elastic ligament, which assists the muscles, which elevate the head, to keep it in its horizontal position, and to raise it after it has been depressed. 5. The _immediate organs of sense_ consist in like manner of moving fibres enveloped in the medullary substance above mentioned; and are erroneously supposed to be simply an expansion of the nervous medulla, as the retina of the eye, and the rete mucosum of the skin, which are the immediate organs of vision, and of touch. Hence when we speak of the contractions of the fibrous parts of the body, we shall mean both the contractions of the muscles, and those of the immediate organs of sense. These _fibrous motions_ are thus distinguished from the _sensorial motions_ above mentioned. 6. The _external organs_ of sense are the coverings of the immediate organs of sense, and are mechanically adapted for the reception or transmission of peculiar bodies, or of their qualities, as the cornea and humours of the eye, the tympanum of the ear, the cuticle of the fingers and tongue. 7. The word _idea_ has various meanings in the writers of metaphysic: it is here used simply for those notions of external things, which our organs of sense bring us acquainted with originally; and is defined a contraction, or motion, or configuration, of the fibres, which constitute the immediate organ of sense; which will be explained at large in another part of the work. Synonymous with the word idea, we shall sometimes use the words _sensual motion_ in contradistinction to _muscular motion_. 8. The word _perception_ includes both the action of the organ of sense in consequence of the impact of external objects, and our attention to that action; that is, it expresses both the motion of the organ of sense, or idea, and the pain or pleasure that succeeds or accompanies it. 9. The pleasure or pain which necessarily accompanies all those perceptions or ideas which we attend to, either gradually subsides, or is succeeded by other fibrous motions. In the latter case it is termed _sensation_, as explained in Sect. V. 2, and VI. 2.--The reader is intreated to keep this in his mind, that through all this treatise the word sensation is used to express pleasure or pain only in its active state, by whatever means it is introduced into the system, without any reference to the stimulation of external objects. 10. The vulgar use of the word _memory_ is too unlimited for our purpose: those ideas which we voluntarily recall are here termed ideas of _recollection_, as when we will to repeat the alphabet backwards. And those ideas which are suggested to us by preceding ideas are here termed ideas of _suggestion_, as whilst we repeat the alphabet in the usual order; when by habits previously acquired B is suggested by A, and C by B, without any effort of deliberation. 11. The word _association_ properly signifies a society or convention of things in some respects similar to each other. We never say in common language, that the effect is associated with the cause, though they necessarily accompany or succeed each other. Thus the contractions of our muscles and organs of sense may be said to be associated together, but cannot with propriety be said to be associated with irritations, or with volition, or with sensation; because they are caused by them, as mentioned in Sect. IV. When fibrous contractions succeed other fibrous contractions, the connection is termed _association_; when fibrous contractions succeed sensorial motions, the connection is termed _causation_; when fibrous and sensorial motions reciprocally introduce each other in progressive trains or tribes, it is termed _catenation_ of animal motions. All these connections are said to be produced by _habit_; that is, by frequent repetition. 12. It may be proper to observe, that by the unavoidable idiom of our language the ideas of perception, of recollection, or of imagination, in the plural number signify the ideas belonging to perception, to recollection, or to imagination; whilst the idea of perception, of recollection, or of imagination, in the singular number is used for what is termed "a reflex idea of any of those operations of the sensorium." 13. By the word _stimulus_ is not only meant the application of external bodies to our organs of sense and muscular fibres, which excites into action the sensorial power termed irritation; but also pleasure or pain, when they excite into action the sensorial power termed sensation; and desire or aversion, when they excite into action the power of volition; and lastly, the fibrous contractions which precede association; as is further explained in Sect. XII. 2. 1. * * * * * SECT. III. THE MOTIONS OF THE RETINA DEMONSTRATED BY EXPERIMENTS. I. _Of animal motions and of ideas._ II. _The fibrous structure of the retina._ III. _The activity of the retina in vision._ 1. _Rays of light have no momentum._ 2. _Objects long viewed become fainter._ 3. _Spectra of black objects become luminous._ 4. _Varying spectra from gyration._ 5. _From long inspection of various colours._ IV. _Motions of the organs of sense constitute ideas._ 1. _Light from pressing the eye-ball, and sound from the pulsation of the carotid artery._ 2. _Ideas in sleep mistaken for perceptions._ 3. _Ideas of imagination produce pain and sickness like sensations._ 4. _When the organ of sense is destroyed, the ideas belonging to that sense perish._ V. _Analogy between muscular motions and sensual motions, or ideas._ 1. _They are both originally excited by irritations._ 2. _And associated together in the same manner._ 3. _Both act in nearly the same times._ 4. _Are alike strengthened or fatigued by exercise._ 5. _Are alike painful from inflammation._ 6. _Are alike benumbed by compression._ 7. _Are alike liable to paralysis._ 8. _To convulsion._ 9. _To the influence of old age._--VI. _Objections answered._ 1. _Why we cannot invent new ideas._ 2. _If ideas resemble external objects._ 3. _Of the imagined sensation in an amputated limb._ 4. _Abstract ideas._--VII. _What are ideas, if they are not animal motions?_ Before the great variety of animal motions can be duly arranged into natural classes and orders, it is necessary to smooth the way to this yet unconquered field of science, by removing some obstacles which thwart our passage. I. To demonstrate that the retina and other immediate organs of sense possess a power of motion, and that these motions constitute our ideas, according to the fifth and seventh of the preceding assertions, claims our first attention. Animal motions are distinguished from the communicated motions, mentioned in the first section, as they have no mechanical proportion to their cause; for the goad of a spur on the skin of a horse shall induce him to move a load of hay. They differ from the gravitating motions there mentioned as they are exerted with equal facility in all directions, and they differ from the chemical class of motions, because no apparent decompositions or new combinations are produced in the moving materials. Hence, when we say animal motion is excited by irritation, we do not mean that the motion bears any proportion to the mechanical impulse of the stimulus; nor that it is affected by the general gravitation of the two bodies; nor by their chemical properties, but solely that certain animal fibres are excited into action by something external to the moving organ. In this sense the stimulus of the blood produces the contractions of the heart; and the substances we take into our stomach and bowels stimulate them to perform their necessary functions. The rays of light excite the retina into animal motion by their stimulus; at the same time that those rays of light themselves are physically converged to a focus by the inactive humours of the eye. The vibrations of the air stimulate the auditory nerve into animal action; while it is probable that the tympanum of the ear at the same time undergoes a mechanical vibration. To render this circumstance more easy to be comprehended, _motion may be defined to be a variation of figure_; for the whole universe may be considered as one thing possessing a certain figure; the motions of any of its parts are a variation of this figure of the whole: this definition of motion will be further explained in Section XIV. 2. 2. on the production of ideas. Now the motions of an organ of sense are a succession of configurations of that organ; these configurations succeed each other quicker or slower; and whatever configuration of this organ of sense, that is, whatever portion of the motion of it is, or has usually been, attended to, constitutes an idea. Hence the configuration is not to be considered as an effect of the motion of the organ, but rather as a part or temporary termination of it; and that, whether a pause succeeds it, or a new configuration immediately takes place. Thus when a succession of moving objects are presented to our view, the ideas of trumpets, horns, lords and ladies, trains and canopies, are configurations, that is, parts or links of the successive motions of the organ of vision. [Illustration: Plate I.] These motions or configurations of the organs of sense differ from the sensorial motions to be described hereafter, as they appear to be simply contractions of the fibrous extremities of those organs, and in that respect exactly resemble the motions or contractions of the larger muscles, as appears from the following experiment. Place a circular piece of red silk about an inch in diameter on a sheet of white paper in a strong light, as in Plate I.--look for a minute on this area, or till the eye becomes somewhat fatigued, and then, gently closing your eyes, and shading them with your hand, a circular green area of the same apparent diameter becomes visible in the closed eye. This green area is the colour reverse to the red area, which had been previously inspected, as explained in the experiments on ocular spectra at the end of the work, and in Botanical Garden, P. 1. additional note, No. 1. Hence it appears, that a part of the retina, which had been fatigued by contraction in one direction, relieves itself by exerting the antagonist fibres, and producing a contraction in an opposite direction, as is common in the exertions of our muscles. Thus when we are tired with long action of our arms in one direction, as in holding a bridle on a journey, we occasionally throw them into an opposite position to relieve the fatigued muscles. Mr. Locke has defined an idea to be "whatever is present to the mind;" but this would include the exertions of volition, and the sensations of pleasure and pain, as well as those operations of our system, which acquaint us with external objects; and is therefore too unlimited for our purpose. Mr. Lock seems to have fallen into a further error, by conceiving, that the mind could form a general or abstract idea by its own operation, which was the copy of no particular perception; as of a triangle in general, that was neither acute, obtuse, nor right angled. The ingenious Dr. Berkley and Mr. Hume have demonstrated, that such general ideas have no existence in nature, not even in the mind of their celebrated inventor. We shall therefore take for granted at present, that our recollection or imagination of external objects consists of a partial repetition of the perceptions, which were excited by those external objects, at the time we became acquainted with them; and that our reflex ideas of the operations of our minds are partial repetitions of those operations. II. The following article evinces that the organ of vision consists of a fibrous part as well as of the nervous medulla, like other white muscles; and hence, as it resembles the muscular parts of the body in its structure, we may conclude, that it must resemble them in possessing a power of being excited into animal motion.--The subsequent experiments on the optic nerve, and on the colours remaining in the eye, are copied from a paper on ocular spectra published in the seventy-sixth volume of the Philos. Trans. by Dr. R. Darwin of Shrewsbury; which, as I shall have frequent occasion to refer to, is reprinted in this work, Sect. XL. The retina of an ox's eye was suspended in a glass of warm water, and forcibly torn in a few places; the edges of these parts appeared jagged and hairy, and did not contract and become smooth like simple mucus, when it is distended till it breaks; which evinced that it consisted of fibres. This fibrous construction became still more distinct to the light by adding some caustic alcali to the water; as the adhering mucus was first eroded, and the hair-like fibres remained floating in the vessel. Nor does the degree of transparency of the retina invalidate this evidence of its fibrous structure, since Leeuwenhoek has shewn, that the crystalline humour itself consists of fibres. Arc. Nat. V. I. 70. Hence it appears, that as the muscles consist of larger fibres intermixed with a smaller quantity of nervous medulla, the organ of vision consists of a greater quantity of nervous medulla intermixed with smaller fibres. It is probable that the locomotive muscles of microscopic animals may have greater tenuity than these of the retina; and there is reason to conclude from analogy, that the other immediate organs of sense, as the portio mollis of the auditory nerve, and the rete mucosum of the skin, possess a similarity of structure with the retina, and a similar power of being excited into animal motion. III. The subsequent articles shew, that neither mechanical impressions, nor chemical combinations of light, but that the animal activity of the retina constitutes vision. 1. Much has been conjectured by philosophers about the momentum of the rays of light; to subject this to experiment a very light horizontal balance was constructed by Mr. Michel, with about an inch square of thin leaf-copper suspended at each end of it, as described in Dr. Priestley's History of Light and Colours. The focus of a very large convex mirror was thrown by Dr. Powel, in his lectures on experimental philosophy, in my presence, on one wing of this delicate balance, and it receded from the light; thrown on the other wing, it approached towards the light, and this repeatedly; so that no sensible impulse could be observed, but what might well be ascribed to the ascent of heated air. Whence it is reasonable to conclude, that the light of the day must be much too weak in its dilute state to make any mechanical impression on so tenacious a substance as the retina of the eye.--Add to this, that as the retina is nearly transparent, it could therefore make less resistance to the mechanical impulse of light; which, according, to the observations related by Mr. Melvil in the Edinburgh Literary Essays, only communicates heat, and should therefore only communicate momentum, where it is obstructed, reflected, or refracted.--From whence also may be collected the final cause of this degree of transparency of the retina, viz. left by the focus of stronger lights, heat and pain should have been produced in the retina, instead of that stimulus which excites it into animal motion. 2. On looking long on an area of scarlet silk of about an inch in diameter laid on white paper, as in Plate I. the scarlet colour becomes fainter, till at length it entirely vanishes, though the eye is kept uniformly and steadily upon it. Now if the change or motion of the retina was a mechanical impression, or a chemical tinge of coloured light, the perception would every minute become stronger and stronger,--whereas in this experiment it becomes every instant weaker and weaker. The same circumstance obtains in the continued application of sound, or of sapid bodies, or of odorous ones, or of tangible ones, to their adapted organs of sense. [Illustration: Plate II.] Thus when a circular coin, as a shilling, is pressed on the palm of the hand, the sense of touch is mechanically compressed; but it is the stimulus of this pressure that excites the organ of touch into animal action, which constitutes the perception of hardness and of figure; for in some minutes the perception ceases, though the mechanical pressure of the object remains. 3. Make with ink on white paper a very black spot about half an inch in diameter, with a tail about an inch in length, so as to resemble a tadpole, as in Plate II.; look steadfastly for a minute on the center of this spot, and, on moving the eye a little, the figure of the tadpole will be seen on the white part of the paper; which figure of the tadpole will appear more luminous than the other part of the white paper; which can only be explained by supposing that a part of the retina, on which the tadpole was delineated, to have become more sensible to light than the other parts of it, which were exposed to the white paper; and not from any idea of mechanical impression or chemical combination of light with the retina. 4. When any one turns round rapidly, till he becomes dizzy, and falls upon the ground, the spectra of the ambient objects continue to present themselves in rotation, and he seems to behold the objects still in motion. Now if these spectra were impressions on a passive organ, they either must continue as they were received last, or not continue at all. 5. Place a piece of red silk about an inch in diameter on a sheet of white paper in a strong light, as in Plate I; look steadily upon it from the distance of about half a yard for a minute; then closing your eye-lids, cover them with your hands and handkerchief, and a green spectrum will be seen in your eyes resembling in form the piece of red silk. After some seconds of time the spectrum will disappear, and in a few more seconds will reappear; and thus alternately three or four times, if the experiment be well made, till at length it vanishes entirely. [Illustration: Plate III.] 6. Place a circular piece of white paper, about four inches in diameter, in the sunshine, cover the center of this with a circular piece of black silk, about three inches in diameter; and the center of the black silk with a circle of pink silk, about two inches in diameter; and the center of the pink silk with a circle of yellow silk, about one inch in diameter; and the center of this with a circle of blue silk, about half an inch in diameter; make a small spot with ink in the center of the blue silk, as in Plate III.; look steadily for a minute on this central spot, and then closing your eyes, and applying your hand at about an inch distance before them, so as to prevent too much or too little light from passing through the eye-lids, and you will see the most beautiful circles of colours that imagination can conceive; which are most resembled by the colours occasioned by pouring a drop or two of oil on a still lake in a bright day. But these circular irises of colours are not only different from the colours of the silks above mentioned, but are at the same time perpetually changing as long as they exist. From all these experiments it appears, that these spectra in the eye are not owing to the mechanical impulse of light impressed on the retina; nor to its chemical combination with that organ; nor to the absorption and emission of light, as is supposed, perhaps erroneously, to take place in calcined shells and other phosphorescent bodies, after having been exposed to the light: for in all these cases the spectra in the eye should either remain of the same colour, or gradually decay, when the object is withdrawn; and neither their evanescence during the presence of their object, as in the second experiment, nor their change from dark to luminous, as in the third experiment, nor their rotation, as in the fourth experiment, nor the alternate presence and evanescence of them, as in the fifth experiment, nor the perpetual change of colours of them, as in the last experiment, could exist. IV. The subsequent articles shew, that these animal motions or configurations of our organs of sense constitute our ideas. 1. If any one in the dark presses the ball of his eye, by applying his finger to the external corner of it, a luminous appearance is observed; and by a smart stroke on the eye great slashes of fire are perceived. (Newton's Optics.) So that when the arteries, that are near the auditory nerve, make stronger pulsations than usual, as in some fevers, an undulating sound is excited in the ears. Hence it is not the presence of the light and sound, but the motions of the organ, that are immediately necessary to constitute the perception or idea of light and sound. 2. During the time of sleep, or in delirium, the ideas of imagination are mistaken for the perceptions of external objects; whence it appears, that these ideas of imagination, are no other than a reiteration of those motions of the organs of sense, which were originally excited by the stimulus of external objects: and in our waking hours the simple ideas, that we call up by recollection or by imagination, as the colour of red, or the smell of a rose, are exact resemblances of the same simple ideas from perception; and in consequence must be a repetition of those very motions. 3. The disagreeable sensation called the tooth-edge is originally excited by the painful jarring of the teeth in biting the edge of the glass, or porcelain cup, in which our food was given us in our infancy, as is further explained in the Section XVI. 10, on Instinct.--This disagreeable sensation is afterwards excitable not only by a repetition of the sound, that was then produced, but by imagination alone, as I have myself frequently experienced; in this case the idea of biting a china cup, when I imagine it very distinctly, or when I see another person bite a cup or glass, excites an actual pain in the nerves of my teeth. So that this idea and pain seem to be nothing more than the reiterated motions of those nerves, that were formerly so disagreeably affected. Other ideas that are excited by imagination or recollection in many instances produce similar effects on the constitution, as our perceptions had formerly produced, and are therefore undoubtedly a repetition of the same motions. A story which the celebrated Baron Van Swieton relates of himself is to this purpose. He was present when the putrid carcase of a dead dog exploded with prodigious stench; and some years afterwards, accidentally riding along the same road, he was thrown into the same sickness and vomiting by the idea of the stench, as he had before experienced from the perception of it. 4. Where the organ of sense is totally destroyed, the ideas which were received by that organ seem to perish along with it, as well as the power of perception. Of this a satisfactory instance has fallen under my observation. A gentleman about sixty years of age had been totally deaf for near thirty years: he appeared to be a man of good understanding, and amused himself with reading, and by conversing either by the use of the pen, or by signs made with his fingers, to represent letters. I observed that he had so far forgot the pronunciation of the language, that when he attempted to speak, none of his words had distinct articulation, though his relations could sometimes understand his meaning. But, which is much to the point, he assured me, that in his dreams he always imagined that people conversed with him by signs or writing, and never that he heard any one speak to him. From hence it appears, that with the perceptions of sounds he has also lost the ideas of them; though the organs of speech still retain somewhat of their usual habits of articulation. This observation may throw some light on the medical treatment of deaf people; as it may be learnt from their dreams whether the auditory nerve be paralytic, or their deafness be owing to some defect of the external organ. It rarely happens that the immediate organ of vision is perfectly destroyed. The most frequent causes of blindness are occasioned by defects of the external organ, as in cataracts and obfuscations of the cornea. But I have had the opportunity of conversing with two men, who had been some years blind; one of them had a complete gutta serena, and the other had lost the whole substance of his eyes. They both told me that they did not remember to have ever dreamt of visible objects, since the total loss of their sight. V. Another method of discovering that our ideas are animal motions of the organs of sense, is from considering the great analogy they bear to the motions of the larger muscles of the body. In the following articles it will appear that they are originally excited into action by the irritation of external objects like our muscles; are associated together like our muscular motions; act in similar time with them; are fatigued by continued exertion like them; and that the organs of sense are subject to inflammation, numbness, palsy, convulsion, and the defects of old age, in the same manner as the muscular fibres. 1. All our perceptions or ideas of external objects are universally allowed to have been originally excited by the stimulus of those external objects; and it will be shewn in a succeeding section, that it is probable that all our muscular motions, as well those that are become voluntary as those of the heart and glandular system, were originally in like manner excited by the stimulus of something external to the organ of motion. 2. Our ideas are also associated together after their production precisely in the same manner as our muscular motions; which will likewise be fully explained in the succeeding section. 3. The time taken up in performing an idea is likewise much the same as that taken up in performing a muscular motion. A musician can press the keys of an harpsichord with his fingers in the order of a tune he has been accustomed to play, in as little time as he can run over those notes in his mind. So we many times in an hour cover our eye-balls with our eye-lids without perceiving that we are in the dark; hence the perception or idea of light is not changed for that of darkness in so small a time as the twinkling of an eye; so that in this case the muscular motion of the eye-lid is performed quicker than the perception of light can be changed for that of darkness.--So if a fire-stick be whirled round in the dark, a luminous circle appears to the observer; if it be whirled somewhat slower, this circle becomes interrupted in one part; and then the time taken up in such a revolution of the stick is the same that the observer uses in changing his ideas: thus the [Greek: dolikoskoton enkos] of Homer, the long shadow of the flying javelin, is elegantly designed to give us an idea of its velocity, and not of its length. 4. The fatigue that follows a continued attention of the mind to one object is relieved by changing the subject of our thoughts; as the continued movement of one limb is relieved by moving another in its stead. Whereas a due exercise of the faculties of the mind strengthens and improves those faculties, whether of imagination or recollection; as the exercise of our limbs in dancing or fencing increases the strength and agility of the muscles thus employed. 5. If the muscles of any limb are inflamed, they do not move without pain; so when the retina is inflamed, its motions also are painful. Hence light is as intolerable in this kind of ophthalmia, as pressure is to the finger in the paronychia. In this disease the patients frequently dream of having their eyes painfully dazzled; hence the idea of strong light is painful as well as the reality. The first of these facts evinces that our perceptions are motions of the organs of sense; and the latter, that our imaginations are also motions of the same organs. 6. The organs of sense, like the moving muscles, are liable to become benumbed, or less sensible, from compression. Thus, if any person on a light day looks on a white wall, he may perceive the ramifications of the optic artery, at every pulsation of it, represented by darker branches on the white wall; which is evidently owing to its compressing the retina during the diastole of the artery. Savage Nosolog. 7. The organs of sense and the moving muscles are alike liable to be affected with palsy, as in the gutta serena, and in some cases of deafness; and one side of the face has sometimes lost its power of sensation, but retained its power of motion; other parts of the body have lost their motions but retained their sensation, as in the common hemiplagia; and in other instances both these powers have perished together. 8. In some convulsive diseases a delirium or insanity supervenes, and the convulsions cease; and conversely the convulsions shall supervene, and the delirium cease. Of this I have been a witness many times in a day in the paroxysms of violent epilepsies; which evinces that one kind of delirium is a convulsion of the organs of sense, and that our ideas are the motions of these organs: the subsequent cases will illustrate this observation. Miss G----, a fair young lady, with light eyes and hair, was seized with most violent convulsions of her limbs, with outrageous hiccough, and most vehement efforts to vomit: after near an hour was elapsed this tragedy ceased, and a calm talkative delirium supervened for about another hour; and these relieved each other at intervals during the greatest part of three or four days. After having carefully considered this disease, I thought the convulsions of her ideas less dangerous than those of her muscles; and having in vain attempted to make any opiate continue in her stomach, an ounce of laudanum was rubbed along the spine of her back, and a dram of it was used as an enema; by this medicine a kind of drunken delirium was continued many hours; and when it ceased the convulsions did not return; and the lady continued well many years, except some lighter relapses, which were relieved in the same manner. Miss H----, an accomplished young lady, with light eyes and hair, was seized with convulsions of her limbs, with hiccough, and efforts to vomit, more violent than words can express; these continued near an hour, and were succeeded with a cataleptic spasm of one arm, with the hand applied to her head; and after about twenty minutes these spasms ceased, and a talkative reverie supervened for near an other hour, from which no violence, which it was proper to use, could awaken her. These periods of convulsions, first of the muscles, and then of the ideas, returned twice a day for several weeks; and were at length removed by great doses of opium, after a great variety of other medicines and applications had been in vain experienced. This lady was subject to frequent relapses, once or twice a year for many years, and was as frequently relieved by the same method. Miss W----, an elegant young lady, with black eyes and hair, had sometimes a violent pain of her side, at other times a most painful strangury, which were every day succeeded by delirium; which gave a temporary relief to the painful spasms. After the vain exhibition of variety of medicines and applications by different physicians, for more than a twelvemonth, she was directed to take some doses of opium, which were gradually increased, by which a drunken delirium was kept up for a day or two, and the pains prevented from returning. A flesh diet, with a little wine or beer, instead of the low regimen she had previously used, in a few weeks completely established her health; which, except a few relapses, has continued for many years. 9. Lastly, as we advance in life all the parts of the body become more rigid, and are rendered less susceptible of new habits of motion, though they retain those that were before established. This is sensibly observed by those who apply themselves late in life to music, fencing, or any of the mechanic arts. In the same manner many elderly people retain the ideas they had learned early in life, but find great difficulty in acquiring new trains of memory; insomuch that in extreme old age we frequently see a forgetfulness of the business of yesterday, and at the same time a circumstantial remembrance of the amusements of their youth; till at length the ideas of recollection and activity of the body gradually cease together,--such is the condition of humanity!--and nothing remains but the vital motions and sensations. VI. 1. In opposition to this doctrine of the production of our ideas, it may be asked, if some of our ideas, like other animal motions, are voluntary, why can we not invent new ones, that have not been received by perception? The answer will be better understood after having perused the succeeding section, where it will be explained, that the muscular motions likewise are originally excited by the stimulus of bodies external to the moving organ; and that the will has only the power of repeating the motions thus excited. 2. Another objector may ask, Can the motion of an organ of sense resemble an odour or a colour? To which I can only answer, that it has not been demonstrated that any of our ideas resemble the objects that excite them; it has generally been believed that they do not; but this shall be discussed at large in Sect. XIV. 3. There is another objection that at first view would seem less easy to surmount. After the amputation, of a foot or a finger, it has frequently happened, that an injury being offered to the stump of the amputated limb, whether from cold air, too great pressure, or other accidents, the patient has complained, of a sensation of pain in the foot or finger, that was cut off. Does not this evince that all our ideas are excited in the brain, and not in the organs of sense? This objection is answered, by observing that our ideas of the shape, place, and solidity of our limbs, are acquired by our organs of touch and of sight, which are situated in our fingers and eyes, and not by any sensations in the limb itself. In this case the pain or sensation, which formerly has arisen in the foot or toes, and been propagated along the nerves to the central part of the sensorium, was at the same time accompanied with a visible idea of the shape and place, and with a tangible idea of the solidity of the affected limb: now when these nerves are afterwards affected by any injury done to the remaining stump with a similar degree or kind of pain, the ideas of the shape, place, or solidity of the lost limb, return by association; as these ideas belong to the organs of sight and touch, on which they were first excited. 4. If you wonder what organs of sense can be excited into motion, when you call up the ideas of wisdom or benevolence, which Mr. Locke has termed abstracted ideas; I ask you by what organs of sense you first became acquainted with these ideas? And the answer will be reciprocal; for it is certain that all our ideas were originally acquired by our organs of sense; for whatever excites our perception must be external to the organ that perceives it, and we have no other inlets to knowledge but by our perceptions: as will be further explained in Section XIV. and XV. on the Productions and Classes of Ideas. VII. If our recollection or imagination be not a repetition of animal movements, I ask, in my turn, What is it? You tell me it consists of images or pictures of things. Where is this extensive canvas hung up? or where are the numerous receptacles in which those are deposited? or to what else in the animal system have they any similitude? That pleasing picture of objects, represented in miniature on the retina of the eye, seems to have given rise to this illusive oratory! It was forgot that this representation belongs rather to the laws of light, than to those of life; and may with equal elegance be seen in the camera obscura as in the eye; and that the picture vanishes for ever, when the object is withdrawn. * * * * * SECT. IV. LAWS OF ANIMAL CAUSATION. I. The fibres, which constitute the muscles and organs of sense, possess a power of contraction. The circumstances attending the exertion of this power of CONTRACTION constitute the laws of animal motion, as the circumstances attending the exertion of the power of ATTRACTION constitute the laws of motion of inanimate matter. II. The spirit of animation is the immediate cause of the contraction of animal fibres, it resides in the brain and nerves, and is liable to general or partial diminution or accumulation. III. The stimulus of bodies external to the moving organ is the remote cause of the original contractions of animal fibres. IV. A certain quantity of stimulus produces irritation, which is an exertion of the spirit of animation exciting the fibres into contraction. V. A certain quantity of contraction of animal fibres, if it be perceived at all, produces pleasure; a greater or less quantity of contraction, if it be perceived at all, produces pain; these constitute sensation. VI. A certain quantity of sensation produces desire or aversion; these constitute volition. VII. All animal motions which have occurred at the same time, or in immediate succession, become so connected, that when one of them is reproduced, the other has a tendency to accompany or succeed it. When fibrous contractions succeed or accompany other fibrous contractions, the connection is termed association; when fibrous contractions succeed sensorial motions, the connexion is termed causation; when fibrous and sensorial motions reciprocally introduce each other, it is termed catenation of animal motions. All these connections are said to be produced by habit, that is, by frequent repetition. These laws of animal causation will be evinced by numerous facts, which occur in our daily exertions; and will afterwards be employed to explain the more recondite phænomena of the production, growth, diseases, and decay of the animal system. * * * * * SECT. V. OF THE FOUR FACULTIES OR MOTIONS OF THE SENSORIUM. 1. _Four sensorial powers._ 2. _Irritation, sensation, volition, association defined._ 3. _Sensorial motions distinguished from fibrous motions._ 1. The spirit of animation has four different modes of action, or in other words the animal sensorium possesses four different faculties, which are occasionally exerted, and cause all the contractions of the fibrous parts of the body. These are the faculty of causing fibrous contractions in consequence of the irritations excited by external bodies, in consequence of the sensations of pleasure or pain, in consequence of volition, and in consequence of the associations of fibrous contractions with other fibrous contractions, which precede or accompany them. These four faculties of the sensorium during their inactive state are termed irritability, sensibility, voluntarity, and associability; in their active state they are termed as above, irritation, sensation, volition, association. 2. IRRITATION is an exertion or change of some extreme part of the sensorium residing in the muscles or organs of sense, in consequence of the appulses of external bodies. SENSATION is an exertion or change of the central parts of the sensorium, or of the whole of it, _beginning_ at some of those extreme parts of it, which reside in the muscles or organs of sense. VOLITION is an exertion or change of the central parts of the sensorium, or of the whole of it, _terminating_ in some of those extreme parts of it, which reside in the muscles or organs of sense. ASSOCIATION is an exertion or change of some extreme part of the sensorium residing in the muscles or organs of sense, in consequence of some antecedent or attendant fibrous contractions. 3. These four faculties of the animal sensorium may at the time of their exertions be termed motions without impropriety of language; for we cannot pass from a state of insensibility or inaction to a state of sensibility or of exertion without some change of the sensorium, and every change includes motion. We shall therefore sometimes term the above described faculties _sensorial motions_ to distinguish them from _fibrous motions_; which latter expression includes the motions of the muscles and organs of sense. The active motions of the fibres, whether those of the muscles or organs of sense, are probably simple contractions; the fibres being again elongated by antagonist muscles, by circulating fluids, or sometimes by elastic ligaments, as in the necks of quadrupeds. The sensorial motions, which constitute the sensations of pleasure or pain, and which constitute volition, and which cause the fibrous contractions in consequence of irritation or of association, are not here supposed to be fluctuations or refluctuations of the spirit of animation; nor are they supposed to be vibrations or revibrations, nor condensations or equilibrations of it; but to be changes or motions of it peculiar to life. * * * * * SECT. VI. OF THE FOUR CLASSES OF FIBROUS MOTIONS. I. _Origin of fibrous contractions._ II. _Distribution of them into four classes, irritative motions, sensitive motions, voluntary motions, and associate motions, defined._ I. All the fibrous contractions of animal bodies originate from the sensorium, and resolve themselves into four classes, correspondent with the four powers or motions of the sensorium above described, and from which they have their causation. 1. These fibrous contractions were originally caused by the irritations excited by objects, which are external to the moving organ. As the pulsations of the heart are owing to the irritations excited by the stimulus of the blood; and the ideas of perception are owing to the irritations excited by external bodies. 2. But as painful or pleasurable sensations frequently accompanied those irritations, by habit these fibrous contractions became causeable by the sensations, and the irritations ceased to be necessary to their production. As the secretion of tears in grief is caused by the sensation of pain; and the ideas of imagination, as in dreams or delirium, are excited by the pleasure or pain, with which they were formerly accompanied. 3. But as the efforts of the will frequently accompanied these painful or pleasureable sensations, by habit the fibrous contractions became causable by volition; and both the irritations and sensations ceased to be necessary to their production. As the deliberate locomotions of the body, and the ideas of recollection, as when we will to repeat the alphabet backwards. 4. But as many of these fibrous contractions frequently accompanied other fibrous contractions, by habit they became causable by their associations with them; and the irritations, sensations, and volition, ceased to be necessary to their production. As the actions of the muscles of the lower limbs in fencing are associated with those of the arms; and the ideas of suggestion are associated with other ideas, which precede or accompany them; as in repeating carelessly the alphabet in its usual order after having began it. II. We shall give the following names to these four classes of fibrous motions, and subjoin their definitions. 1. Irritative motions. That exertion or change of the sensorium, which is caused by the appulses of external bodies, either simply subsides, or is succeeded by sensation, or it produces fibrous motions; it is termed irritation, and irritative motions are those contractions of the muscular fibres, or of the organs of sense, that are immediately consequent to this exertion or change of the sensorium. 2. Sensitive motions. That exertion or change of the sensorium, which constitutes pleasure or pain, either simply subsides, or is succeeded by volition, or it produces fibrous motions; it is termed sensation, and the sensitive motions are those contractions of the muscular fibres, or of the organs of sense, that are immediately consequent to this exertion or change of the sensorium. 3. Voluntary motions. That exertion or change of the sensorium, which constitutes desire or aversion, either simply subsides, or is succeeded by fibrous motions; it is then termed volition, and voluntary motions are those contractions of the muscular fibres, or of the organs of sense, that are immediately consequent to this exertion or change of the sensorium. 4. Associate motions. That exertion or change of the sensorium, which accompanies fibrous motions, either simply subsides, or is succeeded by sensation or volition, or it produces other fibrous motions; it is then termed association, and the associate motions are those contractions of the muscular fibres, or of the organs of sense, that are immediately consequent to this exertion or change of the sensorium. * * * * * SECT. VII. OF IRRITATIVE MOTIONS. I. 1. _Some muscular motions are excited by perpetual irritations._ 2. _Others more frequently by sensations._ 3. _Others by volition. Case of involuntary stretchings in paralytic limbs._ 4. _Some sensual motions are excited by perpetual irritations._ 5. _Others more frequently by sensation or volition._ II. 1. _Muscular motions excited by perpetual irritations occasionally become obedient sensation and to volition._ 2. _And the sensual motions._ III. 1. _Other muscular motions are associated with the irritative ones._ 2. _And other ideas with irritative ones. Of letters, language, hieroglyphics. Irritative ideas exist without our attention to them._ I. 1. Many of our muscular motions are excited by perpetual irritations, as those of the heart and arterial system by the circumfluent blood. Many other of them are excited by intermitted irritations, as those of the stomach and bowels by the aliment we swallow; of the bile-ducts by the bile; of the kidneys, pancreas, and many other glands, by the peculiar fluids they separate from the blood; and those of the lacteal and other absorbent vessels by the chyle, lymph, and moisture of the atmosphere. These motions are accelerated or retarded, as their correspondent irritations are increased or diminished, without our attention or consciousness, in the same manner as the various secretions of fruit, gum, resin, wax, and, honey, are produced in the vegetable world, and as the juices of the earth and the moisture of the atmosphere are absorbed by their roots and foliage. 2. Other muscular motions, that are most frequently connected with our sensations, as those of the sphincters of the bladder and anus, and the musculi erectores penis, were originally excited into motion by irritation, for young children make water, and have other evacuations without attention to these circumstances; "et primis etiam ab incunabulis tenduntur sæpius puerorum penes, amore nondum expergefacto." So the nipples of young women are liable to become turgid by irritation, long before they are in a situation to be excited by the pleasure of giving milk to the lips of a child. 3. The contractions of the larger muscles of our bodies, that are most frequently connected with volition, were originally excited into action by internal irritations: as appears from the stretching or yawning of all animals after long sleep. In the beginning of some fevers this irritation of the muscles produces perpetual stretching and yawning; in other periods of fever an universal restlessness arises from the same cause, the patient changing the attitude of his body every minute. The repeated struggles of the foetus in the uterus must be owing to this internal irritation: for the foetus can have no other inducement to move its limbs but the tædium or irksomeness of a continued posture. The following case evinces, that the motions of stretching the limbs after a continued attitude are not always owing to the power of the will. Mr. Dean, a mason, of Austry in Leicestershire, had the spine of the third vertebra of the back enlarged; in some weeks his lower extremities became feeble, and at length quite paralytic: neither the pain of blisters, the heat of fomentations, nor the utmost efforts of the will could produce the least motion in these limbs; yet twice or thrice a day for many months his feet, legs, and thighs, were affected for many minutes with forceable stretchings, attended with the sensation of fatigue; and he at length recovered the use of his limbs, though the spine continued protuberant. The same circumstance is frequently seen in a less degree in the common hemiplagia; and when this happens, I have believed repeated and strong shocks of electricity to have been of great advantage. 4. In like manner the various organs of sense are originally excited into motion by various external stimuli adapted to this purpose, which motions are termed perceptions or ideas; and many of these motions during our waking hours are excited by perpetual irritation, as those of the organs of hearing and of touch. The former by the constant low indistinct noises that murmur around us, and the latter by the weight of our bodies on the parts which support them; and by the unceasing variations of the heat, moisture, and pressure of the atmosphere; and these sensual motions, precisely as the muscular ones above mentioned, obey their correspondent irritations without our attention or consciousness. 5. Other classes of our ideas are more frequently excited by our sensations of pleasure or pain, and others by volition: but that these have all been originally excited by stimuli from external objects, and only vary in their combinations or reparations, has been fully evinced by Mr. Locke: and are by him termed the ideas of perception in contradistinction to those, which he calls the ideas of reflection. II. 1. These muscular motions, that are excited by perpetual irritation, are nevertheless occasionally excitable by the sensations of pleasure or pain, or by volition; as appears by the palpitation of the heart from fear, the increased secretion of saliva at the sight of agreeable food, and the glow on the skin of those who are ashamed. There is an instance told in the Philosophical Transactions of a man, who could for a time stop the motion of his heart when he pleased; and Mr. D. has often told me, be could so far increase the peristaltic motion of his bowels by voluntary efforts, as to produce an evacuation by stool at any time in half an hour. 2. In like manner the sensual motions, or ideas, that are excited by perpetual irritation, are nevertheless occasionally excited by sensation or volition; as in the night, when we listen under the influence of fear, or from voluntary attention, the motions excited in the organ of hearing by the whispering of the air in our room, the pulsation of our own arteries, or the faint beating of a distant watch, become objects of perception. III. 1. Innumerable trains or tribes of other motions are associated with these muscular motions which are excited by irritation; as by the stimulus of the blood in the right chamber of the heart, the lungs are induced to expand themselves; and the pectoral and intercostal muscles, and the diaphragm, act at the same time by their associations with them. And when the pharinx is irritated by agreeable food, the muscles of deglutition are brought into action by association. Thus when a greater light falls on the eye, the iris is brought into action without our attention; and the ciliary process, when the focus is formed before or behind the retina, by their associations with the increased irritative motions of the organ of vision. Many common actions of life are produced in a similar manner. If a fly settle on my forehead, whilst I am intent on my present occupation, I dislodge it with my finger, without exciting my attention or breaking the train of my ideas. 2. In like manner the irritative ideas suggest to us many other trains or tribes of ideas that are associated with them. On this kind of connection, language, letters, hieroglyphics, and every kind of symbol, depend. The symbols themselves produce irritative ideas, or sensual motions, which we do not attend to; and other ideas, that are succeeded by sensation, are excited by their association with them. And as these irritative ideas make up a part of the chain of our waking thoughts, introducing other ideas that engage our attention, though themselves are unattended to, we find it very difficult to investigate by what steps many of our hourly trains of ideas gain their admittance. It may appear paradoxical, that ideas can exist, and not be attended to; but all our perceptions are ideas excited by irritation, and succeeded by sensation. Now when these ideas excited by irritation give us neither pleasure nor pain, we cease to attend to them. Thus whilst I am walking through that grove before my window, I do not run against the trees or the benches, though my thoughts are strenuously exerted on some other object. This leads us to a distinct knowledge of irritative ideas, for the idea of the tree or bench, which I avoid, exists on my retina, and induces by association the action of certain locomotive muscles; though neither itself nor the actions of those muscles engage my attention. Thus whilst we are conversing on this subject, the tone, note, and articulation of every individual word forms its correspondent irritative idea on the organ of hearing; but we only attend to the associated ideas, that are attached by habit to these irritative ones, and are succeeded by sensation; thus when we read the words "PRINTING-PRESS" we do not attend to the shape, size, or existence of the letters which compose these words, though each of them excites a correspondent irritative motion of our organ of vision, but they introduce by association our idea of the most useful of modern inventions; the capacious reservoir of human knowledge, whose branching streams diffuse sciences, arts, and morality, through all nations and all ages. * * * * * SECT. VIII. OF SENSITIVE MOTIONS. I. 1. _Sensitive muscular motions were originally excited into action by irritation._ 2. _And sensitive sensual motions, ideas of imagination, dreams._ II. 1. _Sensitive muscular motions are occasionally obedient to volition._ 2. _And sensitive sensual motions._ III. 1. _Other muscular motions are associated with the sensitive ones._ 2. _And other sensual motions._ I. 1. Many of the motions of our muscles, that are excited into action by irritation, are at the same time accompanied with painful or pleasurable sensations; and at length become by habit causable by the sensations. Thus the motions of the sphincters of the bladder and anus were originally excited into action by irritation; for young children give no attention to these evacuations; but as soon as they become sensible of the inconvenience of obeying these irritations, they suffer the water or excrement to accumulate, till it disagreeably affects them; and the action of those sphincters is then in consequence of this disagreeable sensation. So the secretion of saliva, which in young children is copiously produced by irritation, and drops from their mouths, is frequently attended with the agreeable sensation produced by the mastication of tasteful food;, till at length the sight of such food to a hungry person excites into action these salival glands; as is seen in the slavering of hungry dogs. The motions of those muscles, which are affected by lascivious ideas, and those which are exerted in smiling, weeping, starting from fear, and winking at the approach of danger to the eye, and at times the actions of every large muscle of the body become causable by our sensations. And all these motions are performed with strength and velocity in proportion to the energy of the sensation that excites them, and the quantity of sensorial power. 2. Many of the motions of our organs of sense, or ideas, that were originally excited into action by irritation, become in like manner more frequently causable by our sensations of pleasure or pain. These motions are then termed the ideas of imagination, and make up all the scenery and transactions of our dreams. Thus when any painful or pleasurable sensations possess us, as of love, anger, fear; whether in our sleep or waking hours, the ideas, that have been formerly excited by the objects of these sensations, now vividly recur before us by their connection with these sensations themselves. So the fair smiling virgin, that excited your love by her presence, whenever that sensation recurs, rises before you in imagination; and that with all the pleasing circumstances, that had before engaged your attention. And in sleep, when you dream under the influence of fear, all the robbers, fires, and precipices, that you formerly have seen or heard of, arise before you with terrible vivacity. All these sensual motions, like the muscular ones above mentioned, are performed with strength and velocity in proportion to the energy of the sensation of pleasure or pain, which excites them, and the quantity of sensorial power. II. 1. Many of these muscular motions above described, that are most frequently excited by our sensations, are nevertheless occasionally causable by volition; for we can smile or frown spontaneously, can make water before the quantity or acrimony of the urine produces a disagreeable sensation, and can voluntarily masticate a nauseous drug, or swallow a bitter draught, though our sensation would strongly dissuade us. 2. In like manner the sensual motions, or ideas, that are most frequently excited by our sensations, are nevertheless occasionally causeable by volition, as we can spontaneously call up our last night's dream before us, tracing it industriously step by step through all its variety of scenery and transaction; or can voluntarily examine or repeat the ideas, that have been excited by out disgust or admiration. III. 1. Innumerable trains or tribes of motions are associated with these sensitive muscular motions above mentioned; as when a drop of water falling into the wind-pipe disagreeably affects the air-vessels of the lungs, they are excited into violent action; and with these sensitive motions are associated the actions of the pectoral and intercostal muscles, and the diaphragm; till by their united and repeated succussions the drop is returned through the larinx. The same occurs when any thing disagreeably affects the nostrils, or the stomach, or the uterus; variety of muscles are excited by association into forcible action, not to be suppressed by the utmost efforts of the will; as in sneezing, vomiting, and parturition. 2. In like manner with these sensitive sensual motions, or ideas of imagination, are associated many other trains or tribes of ideas, which by some writers of metaphysics have been classed under the terms of resemblance, causation, and contiguity; and will be more fully treated of hereafter. * * * * * SECT. IX. OF VOLUNTARY MOTIONS. I. 1. _Voluntary muscular motions are originally excited by irritations._ 2. _And voluntary ideas. Of reason._ II. 1. _Voluntary muscular motions are occasionally causable by sensations._ 2. _And voluntary ideas._ III. 1. _Voluntary muscular motions are occasionally obedient to irritations._ 2. _And voluntary ideas._ IV. 1. _Voluntary muscular motions are associated with other muscular motions._ 2. _And voluntary ideas._ When pleasure or pain affect the animal system, many of its motions both muscular and sensual are brought into action; as was shewn in the preceding section, and were called sensitive motions. The general tendency of these motions is to arrest and to possess the pleasure, or to dislodge or avoid the pain: but if this cannot immediately be accomplished, desire or aversion are produced, and the motions in consequence of this new faculty of the sensorium are called voluntary. I. 1. Those muscles of the body that are attached to bones, have in general their principal connections with volition, as I move my pen or raise my body. These motions were originally excited by irritation, as was explained in the section on that subject, afterwards the sensations of pleasure or pain, that accompanied the motions thus excited, induced a repetition of them; and at length many of them were voluntarily practised in succession or in combination for the common purposes of life, as in learning to walk, or to speak; and are performed with strength and velocity in proportion to the energy of the volition, that excites them, and the quantity of sensorial power. 2. Another great class of voluntary motions consists of the ideas of recollection. We will to repeat a certain train of ideas, as of the alphabet backwards; and if any ideas, that do not belong to this intended train, intrude themselves by other connections, we will to reject them, and voluntarily persist in the determined train. So at my approach to a house which I have but once visited, and that at the distance of many months, I will to recollect the names of the numerous family I expect to see there, and I do recollect them. On this voluntary recollection of ideas our faculty of reason depends, as it enables us to acquire an idea of the dissimilitude of any two ideas. Thus if you voluntarily produce the idea of a right-angled triangle, and then of a square; and after having excited these ideas repeatedly, you excite the idea of their difference, which is that of another right-angled triangle inverted over the former; you are said to reason upon this subject, or to compare your ideas. These ideas of recollection, like the muscular motions above mentioned, were originally excited by the irritation of external bodies, and were termed ideas of perception: afterwards the pleasure or pain, that accompanied these motions, induced a repetition of them in the absence of the external body, by which they were first excited; and then they were termed ideas of imagination. At length they become voluntarily practised in succession or in combination for the common purposes of life; as when we make ourselves masters of the history of mankind, or of the sciences they have investigated; and are then called ideas of recollection; and are performed with strength and velocity in proportion to the energy of the volition that excites them, and the quantity of sensorial power. II. 1. The muscular motions above described, that are most frequently obedient to the will are nevertheless occasionally causable by painful or pleasurable sensation, as in the starting from fear, and the contraction of the calf of the leg in the cramp. 2. In like manner the sensual motions, or ideas, that are most frequently connected with volition, are nevertheless occasionally causable by painful or pleasurable sensation. As the histories of men, or the description of places, which we have voluntarily taken pains to remember, sometimes occur to us in our dreams. III. 1. The muscular motions that are generally subservient to volition, are also occasionally causable by irritation, as in stretching the limbs after sleep, and yawning. In this manner a contraction of the arm is produced by passing the electric fluid from the Leyden phial along its muscles; and that even though the limb is paralytic. The sudden motion of the arm produces a disagreeable sensation in the joint, but the muscles seem to be brought into action simply by irritation. 2. The ideas, that are generally subservient to the will, are in like manner occasionally excited by irritation; as when we view again an object, we have before well studied, and often recollected. IV. 1. Innumerable trains or tribes of motions are associated with these voluntary muscular motions above mentioned; as when I will to extend my arm to a distant object, some other muscles are brought into action, and preserve the balance of my body. And when I wish to perform any steady exertion, as in threading a needle, or chopping with an ax, the pectoral muscles are at the same time brought into action to preserve the trunk of the body motionless, and we cease to respire for a time. 2. In like manner the voluntary sensual motions, or ideas of recollection, are associated with many other trains or tribes of ideas. As when I voluntarily recollect a gothic window, that I saw some time ago, the whole front of the cathedral occurs to me at the same time. * * * * * SECT. X. OF ASSOCIATE MOTIONS. I. 1. _Many muscular motions excited by irritations in trains or tribes become associated._ 2. _And many ideas._ II. 1. _Many sensitive muscular motions become associated._ 2. _And many sensitive ideas._ III. 1. _Many voluntary muscular motions become associated._ 2. _And then become obedient to sensation or irritation._ 3. _And many voluntary ideas become associated._ All the fibrous motions, whether muscular or sensual, which are frequently brought into action together, either in combined tribes, or in successive trains, become so connected by habit, that when one of them is reproduced the others have a tendency to succeed or accompany it. I. 1. Many of our muscular motions were originally excited in successive trains, as the contractions of the auricles and of the ventricles of the heart; and others in combined tribes, as the various divisions of the muscles which compose the calf of the leg, which were originally irritated into synchronous action by the tædium or irksomeness of a continued posture. By frequent repetitions these motions acquire associations, which continue during our lives, and even after the destruction of the greatest part of the sensorium; for the heart of a viper or frog will continue to pulsate long after it is taken from the body; and when it has entirely ceased to move, if any part of it is goaded with a pin, the whole heart will again renew its pulsations. This kind of connection we shall term irritative association, to distinguish it from sensitive and voluntary associations. 2. In like manner many of our ideas are originally excited in tribes; as all the objects of sight, after we become so well acquainted with the laws of vision, as to distinguish figure and distance as well as colour; or in trains, as while we pass along the objects that surround us. The tribes thus received by irritation become associated by habit, and have been termed complex ideas by the writers of metaphysics, as this book, or that orange. The trains have received no particular name, but these are alike associations of ideas, and frequently continue during our lives. So the taste of a pine-apple, though we eat it blindfold, recalls the colour and shape of it; and we can scarcely think on solidity without figure. II. 1. By the various efforts of our sensations to acquire or avoid their objects, many muscles are daily brought into successive or synchronous actions; these become associated by habit, and are then excited together with great facility, and in many instances gain indissoluble connections. So the play of puppies and kittens is a representation of their mode of fighting or of taking their prey; and the motions of the muscles necessary for those purposes become associated by habit, and gain a great adroitness of action by these early repetitions: so the motions of the abdominal muscles, which were originally brought into concurrent action, with the protrusive motion of the rectum or bladder by sensation, become so conjoined with them by habit, that they not only easily obey these sensations occasioned by the stimulus of the excrement and urine, but are brought into violent and unrestrainable action in the strangury and tenesmus. This kind of connection we shall term sensitive association. 2. So many of our ideas, that have been excited together or in succession by our sensations, gain synchronous or successive associations, that are sometimes indissoluble but with life. Hence the idea of an inhuman or dishonourable action perpetually calls up before us the idea of the wretch that was guilty of it. And hence those unconquerable antipathies are formed, which some people have to the sight of peculiar kinds of food, of which in their infancy they have eaten to excess or by constraint. III. 1. In learning any mechanic art, as music, dancing, or the use of the sword, we teach many of our muscles to act together or in succession by repeated voluntary efforts; which by habit become formed into tribes or trains of association, and serve all our purposes with great facility, and in some instances acquire an indissoluble union. These motions are gradually formed into a habit of acting together by a multitude of repetitions, whilst they are yet separately causable by the will, as is evident from the long time that is taken up by children in learning to walk and to speak; and is experienced by every one, when he first attempts to skate upon the ice or to swim: these we shall term voluntary associations. 2. All these muscular movements, when they are thus associated into tribes or trains, become afterwards not only obedient to volition, but to the sensations and irritations; and the same movement composes a part of many different tribes or trains of motion. Thus a single muscle, when it acts in consort with its neighbours on one side, assists to move the limb in one direction; and in another, when, it acts with those in its neighbourhood on the other side; and in other directions, when it acts separately or jointly with those that lie immediately under or above it; and all these with equal facility after their associations have been well established. The facility, with which each muscle changes from one associated tribe to another, and that either backwards or forwards, is well observable in the muscles of the arm in moving the windlass of an air-pump; and the slowness of those muscular movements, that have not been associated by habit, may be experienced by any one, who shall attempt to saw the air quick perpendicularly with one hand, and horizontally with the other at the same time. 3. In learning every kind of science we voluntarily associate many tribes and trains of ideas, which afterwards are ready for all the purposes either of volition, sensation, or irritation; and in some instances acquire indissoluble habits of acting together, so as to affect our reasoning, and influence our actions. Hence the necessity of a good education. These associate ideas are gradually formed into habits of acting together by frequent repetition, while they are yet separately obedient to the will; as is evident from the difficulty we experience in gaining so exact an idea of the front of St. Paul's church, as to be able to delineate it with accuracy, or in recollecting a poem of a few pages. And these ideas, thus associated into tribes, not only make up the parts of the trains of volition, sensation, and irritation; but the same idea composes a part of many different tribes and trains of ideas. So the simple idea of whiteness composes a part of the complex idea of snow, milk, ivory; and the complex idea of the letter A composes a part of the several associated trains of ideas that make up the variety of words, in which this letter enters. The numerous trains of these associated ideas are divided by Mr. Hume into three classes, which he has termed contiguity, causation, and resemblance. Nor should we wonder to find them thus connected together, since it is the business of our lives to dispose them into those three classes; and we become valuable to ourselves and our friends, as we succeed in it. Those who have combined an extensive class of ideas by the contiguity of time or place, are men learned in the history of mankind, and of the sciences they have cultivated. Those who have connected a great class of ideas of resemblances, possess the source of the ornaments of poetry and oratory, and of all rational analogy. While those who have connected great classes of ideas of causation, are furnished with the powers of producing effects. These are the men of active wisdom, who lead armies to victory, and kingdoms to prosperity; or discover and improve the sciences, which meliorate and adorn the condition of humanity. * * * * * SECT. XI. ADDITIONAL OBSERVATIONS ON THE SENSORIAL POWERS. I. _Stimulation is of various kinds adapted to the organs of sense, to the muscles, to hollow membranes, and glands. Some objects irritate our senses by repeated impulses._ II. 1. _Sensation and volition frequently affect the whole sensorium._ 2. _Emotions, passions, appetites._ 3. _Origin of desire and aversion. Criterion of voluntary actions, difference of brutes and men._ 4. _Sensibility and voluntarity._ III. _Associations formed before nativity, irritative motions mistaken for officiated ones._ _Irritation._ I. The various organs of sense require various kinds of stimulation to excite them into action; the particles of light penetrate the cornea and humours of the eye, and then irritate the naked retina; rapid particles, dissolved or diffused in water or saliva, and odorous ones, mixed or combined with the air, irritate the extremities of the nerves of taste and smell; which either penetrate, or are expanded on the membranes of the tongue and nostrils; the auditory nerves are stimulated by the vibrations of the atmosphere communicated by means of the tympanum and of the fluid, whether of air or of water, behind it; and the nerves of touch by the hardness of surrounding bodies, though the cuticle is interposed between these bodies and the medulla of the nerve. As the nerves of the senses have each their appropriated objects, which stimulate them into activity; so the muscular fibres, which are the terminations of other sets of nerves, have their peculiar objects, which excite them into action; the longitudinal muscles are stimulated into contraction by extension, whence the stretching or pandiculation after a long continued posture, during which they have been kept in a state of extension; and the hollow muscles are excited into action by distention, as those of the rectum and bladder are induced to protrude their contents from their sense of the distention rather than of the acrimony of those contents. There are other objects adapted to stimulate the nerves, which terminate in variety of membranes, and those especially which form the terminations of canals; thus the preparations of mercury particularly affect the salivary glands, ipecacuanha the stomach, aloe the sphincter of the anus, cantharides that of the bladder, and lastly every gland of the body appears to be indued with a kind of taste, by which it selects or forms each its peculiar fluid from the blood; and by which it is irritated into activity. Many of these external properties of bodies, which stimulate our organs of sense, do not seem to effect this by a single impulse, but by repeated impulses; as the nerve of the ear is probably not excitable by a single vibration of air, nor the optic nerve by a single particle of light; which circumstance produces some analogy between those two senses, at the same time the solidity of bodies is perceived by a single application of a solid body to the nerves of touch, and that even through the cuticle; and we are probably possessed of a peculiar sense to distinguish the nice degrees of heat and cold. The senses of touch and of hearing acquaint us with the mechanical impact and vibration of bodies, those of smell and taste seem to acquaint us with some of their chemical properties, while the sense of vision and of heat acquaint us with the existence of their peculiar fluids. _Sensation and Volition._ II. Many motions are produced by pleasure or pain, and that even in contradiction to the power of volition, as in laughing, or in the strangury; but as no name has been given to pleasure or pain, at the time it is exerted so as to cause fibrous motions, we have used the term sensation for this purpose; and mean it to bear the same analogy to pleasure and pain, that the word volition does to desire and aversion. 1. It was mentioned in the fifth Section, that, what we have termed sensation is a motion of the central parts, or of the whole sensorium, _beginning_ at some of the extremities of it. This appears first, because our pains and pleasures are always caused by our ideas or muscular motions, which are the motions of the extremities of the sensorium. And, secondly, because the sensation of pleasure or pain frequently continues some time after the ideas or muscular motions which excited it have ceased: for we often feel a glow of pleasure from an agreeable reverie, for many minutes after the ideas, that were the subject of it, have escaped our memory; and frequently experience a dejection of spirits without being able to assign the cause of it but by much recollection. When the sensorial faculty of desire or aversion is exerted so as to cause fibrous motions, it is termed volition; which is said in Sect. V. to be a motion of the central parts, or of the whole sensorium, _terminating_ in some of the extremities of it. This appears, first, because our desires and aversions always terminate in recollecting and comparing our ideas, or in exerting our muscles; which are the motions of the extremities of the sensorium. And, secondly, because desire or aversion begins, and frequently continues for a time in the central parts of the sensorium, before it is peculiarly exerted at the extremities of it; for we sometimes feel desire or aversion without immediately knowing their objects, and in consequence without immediately exerting any of our muscular or sensual motions to attain them: as in the beginning of the passion of love, and perhaps of hunger, or in the ennui of indolent people. Though sensation and volition begin or terminate at the extremities or central parts of the sensorium, yet the whole of it is frequently influenced by the exertion of these faculties, as appears from their effects on the external habit: for the whole skin is reddened by shame, and an universal trembling is produced by fear: and every muscle of the body is agitated in angry people by the desire of revenge. There is another very curious circumstance, which shews that sensation and volition are movements of the sensorium in contrary directions; that is, that volition begins at the central parts of it, and proceeds to the extremities; and that sensation begins at the extremities, and proceeds to the central parts: I mean that these two sensorial faculties cannot be strongly exerted at the same time; for when we exert our volition strongly, we do not attend to pleasure or pain; and conversely, when we are strongly affected with the sensation of pleasure or pain, we use no volition. As will be further explained in Section XVIII. on sleep, and Section XXXIV. on volition. 2. All our emotions and passions seem to arise out of the exertions of these two faculties of the animal sensorium. Pride, hope, joy, are the names of particular pleasures: shame, despair, sorrow, are the names of peculiar pains: and love, ambition, avarice, of particular desires: hatred, disgust, fear, anxiety, of particular aversions. Whilst the passion of anger includes the pain from a recent injury, and the aversion to the adversary that occasioned it. And compassion is the pain we experience at the sight of misery, and the desire of relieving it. There is another tribe of desires, which are commonly termed appetites, and are the immediate consequences of the absence of some irritative motions. Those, which arise from defect of internal irritations, have proper names conferred upon them, as hunger, thirst, lust, and the desire of air, when our respiration is impaired by noxious vapours; and of warmth, when we are exposed to too great a degree of cold. But those, whose stimuli are external to the body, are named from the objects, which are by nature constituted to excite them; these desires originate from our past experience of the pleasurable sensations they occasion, as the smell of an hyacinth, or the taste of a pine-apple. Whence it appears, that our pleasures and pains are at least as various and as numerous as our irritations; and that our desires and aversions must be as numerous as our pleasures and pains. And that as sensation is here used as a general term for our numerous pleasures and pains, when they produce the contractions of our fibres; so volition is the general name for our desires and aversions, when they produce fibrous contractions. Thus when a motion of the central parts, or of the whole sensorium, terminates in the exertion of our muscles, it is generally called voluntary action; when it terminates in the exertion of our ideas, it is termed recollection, reasoning, determining. 3. As the sensations of pleasure and pain are originally introduced by the irritations of external objects: so our desires and aversions are originally introduced by those sensations; for when the objects of our pleasures or pains are at a distance, and we cannot instantaneously possess the one, or avoid the other, then desire or aversion is produced, and a voluntary exertion of our ideas or muscles succeeds. The pain of hunger excites you to look out for food, the tree, that shades you, presents its odoriferous fruit before your eyes, you approach, pluck, and eat. The various movements of walking to the tree, gathering the fruit, and masticating it, are associated motions introduced by their connection with sensation; but if from the uncommon height of the tree, the fruit be inaccessible, and you are prevented from quickly possessing the intended pleasure, desire is produced. The consequence of this desire is, first, a deliberation about the means to gain the object of pleasure in process of time, as it cannot be procured immediately; and, secondly, the muscular action necessary for this purpose. You voluntarily call up all your ideas of causation, that are related to the effect you desire, and voluntarily examine and compare them, and at length determine whether to ascend the tree, or to gather stones from the neighbouring brook, is easier to practise, or more promising of success; and, finally, you gather the stones, and repeatedly fling them to dislodge the fruit. Hence then we gain a criterion to distinguish voluntary acts or thoughts from those caused by sensation. As the former are always employed about the _means_ to acquire pleasurable objects, or the _means_ to avoid painful ones; while the latter are employed in the possession of those, which are already in our power. Hence the activity of this power of volition produces the great difference between the human and the brute creation. The ideas and the actions of brutes are almost perpetually employed about their present pleasures, or their present pains; and, except in the few instances which are mentioned in Section XVI, on instinct, they seldom busy themselves about the means of procuring future bliss, or of avoiding future misery; so that the acquiring of languages, the making of tools, and labouring for money, which are all only the means to procure pleasures; and the praying to the Deity, as another means to procure happiness, are characteristic of human nature. 4. As there are many diseases produced by the quantity of the sensation of pain or pleasure being too great or too little; so are there diseases produced by the susceptibility of the constitution to motions causable by these sensations being too dull or too vivid. This susceptibility of the system to sensitive motions is termed sensibility, to distinguish it from sensation, which is the actual existence or exertion of pain or pleasure. Other classes of diseases are owing to the excessive promptitude, or sluggishness of the constitution to voluntary exertions, as well as to the quantity of desire or of aversion. This susceptibility of the system to voluntary motions is termed voluntarity, to distinguish it from volition, which is the exertion of desire or aversion; these diseases will be treated of at length in the progress of the work. _Association._ III. 1. It is not easy to assign a cause, why those animal movements, that have once occurred in succession, or in combination, should afterwards have a tendency to succeed or accompany each other. It is a property of animation, and distinguishes this order of being from the other productions of nature. When a child first wrote the word man, it was distinguished in his mind into three letters, and those letters into many parts of letters; but by repeated use the word man becomes to his hand in writing it, as to his organs of speech in pronouncing it, but one movement without any deliberation, or sensation, or irritation, interposed between the parts of it. And as many separate motions of our muscles thus become united, and form, as it were, one motion; so each separate motion before such union may be conceived to consist of many parts or spaces moved through; and perhaps even the individual fibres of our muscles have thus gradually been brought to act in concert, which habits began to be acquired as early as the very formation of the moving organs, long before the nativity of the animal; as explained in the Section XVI. 2. on instinct. 2. There are many motions of the body, belonging to the irritative class, which might by a hasty observer be mistaken for associated ones; as the peristaltic motion of the stomach and intestines, and the contractions of the heart and arteries, might be supposed to be associated with the irritative motions of their nerves of sense, rather than to be excited by the irritation of their muscular fibres by the distention, acrimony, or momentum of the blood. So the distention or elongation of muscles by objects external to them irritates them into contraction, though the cuticle or other parts may intervene between the stimulating body and the contracting muscle. Thus a horse voids his excrement when its weight or bulk irritates the rectum or sphincter ani. These muscles act from the irritation of distention, when he excludes his excrement, but the muscles of the abdomen and diaphragm are brought into motion by association with those of the sphincter and rectum. * * * * * SECT. XII. OF STIMULUS, SENSORIAL EXERTION, AND FIBROUS CONTRACTION. I. Of fibrous contraction. 1. _Two particles of a fibre cannot approach without the intervention of something, as in magnetism, electricity, elasticity. Spirit of life is not electric ether. Galvani's experiments._ 2. _Contraction of a fibre._ 3. _Relaxation succeeds._ 4. _Successive contractions, with intervals. Quick pulse from debility, from paucity of blood. Weak contractions performed in less time, and with shorter intervals._ 5. _Last situation of the fibres continues after contraction._ 6. _Contraction greater than usual induces pleasure or pain._ 7. _Mobility of the fibres uniform. Quantity of sensorial power fluctuates. Constitutes excitability._ II. Of sensorial exertion. 1. _Animal motion includes stimulus, sensorial power, and contractile fibres. The sensorial faculties act separately or conjointly. Stimulus of four kinds. Strength and weakness defined. Sensorial power perpetually exhausted and renewed. Weakness from defect of stimulus. From defect of sensorial power, the direct and indirect debility of Dr. Brown. Why we become warm in Buxton bath after a time, and see well after a time in a darkish room. Fibres may act violently, or with their whole force, and yet feebly. Great exertion in inflammation explained. Great muscular force of some insane people._ 2. _Occasional accumulation of sensorial power in muscles subject to constant stimulus. In animals sleeping in winter. In eggs, seeds, schirrous tumours, tendons, bones._ 3. _Great exertion introduces pleasure or pain. Inflammation. Libration of the system between torpor and activity. Fever-fits._ 4. _Desire and aversion introduced. Excess of volition cures fevers._ III. Of repeated stimulus. 1. _A stimulus repeated too frequently looses effect. As opium, wine, grief. Hence old age. Opium and aloes in small doses._ 2. _A stimulus not repeated too frequently does not lose effect. Perpetual movement of the vital organs._ 3. _A stimulus repeated at uniform times produces greater effect. Irritation combined with association._ 4. _A stimulus repeated frequently and uniformly may be withdrawn, and the action of the organ will continue. Hence the bark cures agues, and strengthens weak constitutions._ 5. _Defect of stimulus repeated at certain intervals causes fever-fits._ 6. _Stimulus long applied ceases to act a second time._ 7. _If a stimulus excites sensation in an organ not usually excited into sensation, inflammation is produced._ IV. Of stimulus greater than natural. 1. _A stimulus greater than natural diminishes the quantity of sensorial power in general._ 2. _In particular organs._ 3. _Induces the organ into spasmodic actions._ 4. _Induces the antagonist fibres into action._ 5. _Induces the organ into convulsive or fixed spasms._ 6. _Produces paralysis of the organ._ V. Of stimulus less than natural. 1. _Stimulus less than natural occasions accumulation of sensorial power in general._ 2. _In particular organs, flushing of the face in a frosty morning. In fibres subject to perpetual stimulus only. Quantity of sensorial power inversely as the stimulus._ 3. _Induces pain. As of cold, hunger, head-ach._ 4. _Induces more feeble and frequent contraction. As in low fevers. Which are frequently owing to deficiency of sensorial power rather than to deficiency of stimulus._ 5. _Inverts successive trains of motion. Inverts ideas._ 6. _Induces paralysis and death._ VI. Cure of increased exertion. 1. _Natural cure of exhaustion of sensorial power._ 2. _Decrease the irritations. Venesection. Cold. Abstinence._ 3. _Prevent the previous cold fit. Opium. Bark. Warmth. Anger. Surprise._ 4. _Excite some other part of the system. Opium and warm bath relieve pains both from defect and from excess of stimulus._ 5. _First increase the stimulus above, and then decrease it beneath the natural quantity._ VII. Cure of decreased exertion. 1. _Natural cure by accumulation of sensorial power. Ague-fits. Syncope._ 2. _Increase the stimulation, by wine, opium, given so as not to intoxicate. Cheerful ideas._ 3. _Change the kinds of stimulus._ 4. _Stimulate the associated organs. Blisters of use in heart-burn, and cold extremities._ 5. _Decrease the stimulation for a time, cold bath._ 6. _Decrease the stimulation below natural, and then increase it above natural. Bark after emetics. Opium after venesection. Practice of Sydenham in chlorosis._ 7. _Prevent unnecessary expenditure of sensorial power. Decumbent posture, silence, darkness. Pulse quickened by rising out of bed._ 8. _To the greatest degree of quiescence apply the least stimulus. Otherwise paralysis or inflammation of the organ ensues. Gin, wine, blisters, destroy by too great stimulation in fevers with debility. Intoxication in the slightest degree succeeded by debility. Golden rule for determining the best degree of stimulus in low fevers. Another golden rule for determining the quantity of spirit which those, who are debilitated by drinking it, may safely omit._ I. _Of fibrous contraction._ 1. If two particles of iron lie near each other without motion, and afterwards approach each other; it is reasonable to conclude that something besides the iron particles is the cause of their approximation; this invisible something is termed magnetism. In the same manner, if the particles, which compose an animal muscle, do not touch each other in the relaxed state of the muscle, and are brought into contact during the contraction of the muscle, it is reasonable to conclude, that some other agent is the cause of this new approximation. For nothing can act, where it does not exist; for to act includes to exist; and therefore the particles of the muscular fibre (which in its state of relaxation are supposed not to touch) cannot affect each other without the influence of some intermediate agent; this agent is here termed the spirit of animation, or sensorial power, but may with equal propriety be termed the power, which causes contraction; or may be called by any other name, which the reader may choose to affix to it. The contraction of a muscular fibre may be compared to the following electric experiment, which is here mentioned not as a philosophical analogy, but as an illustration or simile to facilitate the conception of a difficult subject. Let twenty very small Leyden phials properly coated be hung in a row by fine silk threads at a small distance from each other; let the internal charge of one phial be positive, and of the other negative alternately, if a communication be made from the internal surface of the first to the external surface of the last in the row, they will all of them instantly approach each other, and thus shorten a line that might connect them like a muscular fibre. See Botanic Garden, p. 1. Canto I. 1. 202, note on Gymnotus. The attractions of electricity or of magnetism do not apply philosophically to the illustration of the contraction of animal fibres, since the force of those attractions increases in some proportion inversely as the distance, but in muscular motion there appears no difference in velocity or strength during the beginning or end of the contraction, but what may be clearly ascribed to the varying mechanic advantage in the approximation of one bone to another. Nor can muscular motion be assimilated with greater plausibility to the attraction of cohesion or elasticity; for in bending a steel spring, as a small sword, a less force is required to bend it the first inch than the second; and the second than the third; the particles of steel on the convex side of the bent spring endeavouring to restore themselves more powerfully the further they are drawn from each other. See Botanic Garden, P. I. addit. Note XVIII. I am aware that this may be explained another way, by supposing the elasticity of the spring to depend more on the compression of the particles on the concave side than on the extension of them on the convex side; and by supposing the elasticity of the elastic gum to depend more on the resistance to the lateral compression of its particles than to the longitudinal extension of them. Nevertheless in muscular contraction, as above observed, there appears no difference in the velocity or force of it at its commencement or at its termination; from whence we must conclude that animal contraction is governed by laws of its own, and not by those of mechanics, chemistry, magnetism, or electricity. On these accounts I do not think the experiments conclusive, which were lately published by Galvani, Volta, and others, to shew a similitude between the spirit of animation, which contracts the muscular fibres, and the electric fluid. Since the electric fluid may act only as a more potent stimulus exciting the muscular fibres into action, and not by supplying them with a new quantity of the spirit of life. Thus in a recent hemiplegia I have frequently observed, when the patient yawned and stretched himself, that the paralytic limbs moved also, though they were totally disobedient to the will. And when he was electrified by passing shocks from the affected hand to the affected foot, a motion of the paralytic limbs was also produced. Now as in the act of yawning the muscles of the paralytic limbs were excited into action by the stimulus of the irksomeness of a continued posture, and not by any additional quantity of the spirit of life; so we may conclude, that the passage of the electric fluid, which produced a similar effect, acted only as a stimulus, and not by supplying any addition of sensorial power. If nevertheless this theory should ever become established, a stimulus must be called an eductor of vital ether; which stimulus may consist of sensation or volition, as in the electric eel, as well as in the appulses of external bodies; and by drawing off the charges of vital fluid may occasion the contraction or motions of the muscular fibres, and organs of sense. 2. The immediate effect of the action of the spirit of animation or sensorial power on the fibrous parts of the body, whether it acts in the mode of irritation, sensation, volition, or association, is a contraction of the animal fibre, according to the second law of animal causation. Sect. IV. Thus the stimulus of the blood induces the contraction of the heart; the agreeable taste of a strawberry produces the contraction of the muscles of deglutition; the effort of the will contracts the muscles, which move the limbs in walking; and by association other muscles of the trunk are brought into contraction to preserve the balance of the body. The fibrous extremities of the organs of sense have been shewn, by the ocular spectra in Sect. III. to suffer similar contraction by each of the above modes of excitation; and by their configurations to constitute our ideas. 3. After animal fibres have for some time been excited into contraction, a relaxation succeeds, even though the exciting cause continues to act. In respect to the irritative motions this is exemplified in the peristaltic contractions of the bowels; which cease and are renewed alternately, though the stimulus of the aliment continues to be uniformly applied; in the sensitive motions, as in strangury, tenesmus, and parturition, the alternate contractions and relaxations of the muscles exist, though the stimulus is perpetual. In our voluntary exertions it is experienced, as no one can hang long by the hands, however vehemently he wills so to do; and in the associate motions the constant change of our attitudes evinces the necessity of relaxation to those muscles, which have been long in action. This relaxation of a muscle after its contraction, even though the stimulus continues to be applied, appears to arise from the expenditure or diminution of the spirit of animation previously resident in the muscle, according to the second law of animal causation in Sect. IV. In those constitutions, which are termed weak, the spirit of animation becomes sooner exhausted, and tremulous motions are produced, as in the hands of infirm people, when they lift a cup to their mouths. This quicker exhaustion of the spirit of animation is probably owing to a less quantity of it residing in the acting fibres, which therefore more frequently require a supply from the nerves, which belong to them. 4. If the sensorial power continues to act, whether it acts in the mode of irritation, sensation, volition, or association, a new contraction of the animal fibre succeeds after a certain interval; which interval is of shorter continuance in weak people than in strong ones. This is exemplified in the shaking of the hands of weak people, when they attempt to write. In a manuscript epistle of one of my correspondents, which is written in a small hand, I observed from four to six zigzags in the perpendicular stroke of every letter, which shews that both the contractions of the fingers, and intervals between them, must have been performed in very short periods of time. The times of contraction of the muscles of enfeebled people being less, and the intervals between those contractions being less also, accounts for the quick pulse in fevers with debility, and in dying animals. The shortness of the intervals between one contraction and another in weak constitutions, is probably owing to the general deficiency of the quantity of the spirit of animation, and that therefore there is a less quantity of it to be received at each interval of the activity of the fibres. Hence in repeated motions, as of the fingers in performing on the harpsichord, it would at first sight appear, that swiftness and strength were incompatible; nevertheless the single contraction of a muscle is performed with greater velocity as well as with greater force by vigorous constitutions, as in throwing a javelin. There is however another circumstance, which may often contribute to cause the quickness of the pulse in nervous fevers, as in animals bleeding to death in the slaughter-house; which is the deficient quantity of blood; whence the heart is but half distended, and in consequence sooner contracts. See Sect. XXXII. 2. 1. For we must not confound frequency of repetition with quickness of motion, or the number of pulsations with the velocity, with which the fibres, which constitute the coats of the arteries, contract themselves. For where the frequency of the pulsations is but seventy-five in a minute, as in health; the contracting fibres, which constitute the sides of the arteries, may move through a greater space in a given time, than where the frequency of pulsation is one hundred and fifty in a minute, as in some fevers with great debility. For if in those fevers the arteries do not expand themselves in their diastole to more than half the usual diameter of their diastole in health, the fibres which constitute their coats, will move through a less space in a minute than in health, though they make two pulsations for one. Suppose the diameter of the artery during its systole to be one line, and that the diameter of the same artery during its diastole is in health is four lines, and in a fever with, great debility only two lines. It follows, that the arterial fibres contract in health from a circle of twelve lines in circumference to a circle of three lines in circumference, that is they move through a space of nine lines in length. While the arterial fibres in the fever with debility would twice contract from a circle of six lines to a circle of three lines; that is while they move through a space equal to six lines. Hence though the frequency of pulsation in fever be greater as two to one, yet the velocity of contraction in health is greater as nine to six, or as three to two. On the contrary in inflammatory diseases with strength, as in the pleurisy, the velocity of the contracting sides of the arteries is much greater than in health, for if we suppose the number of pulsations in a pleurisy to be half as much more than in health, that is as one hundred and twenty to eighty, (which is about what generally happens in inflammatory diseases) and if the diameter of the artery in diastole be one third greater than in health, which I believe is near the truth, the result will be, that the velocity of the contractile sides of the arteries will be in a pleurisy as two and a half to one, compared to the velocity of their contraction in a state of health, for if the circumference of the systole of the artery be three lines, and the diastole in health be twelve lines in circumference, and in a pleurisy eighteen lines; and secondly, if the artery pulsates thrice in the diseased state for twice in the healthy one, it follows, that the velocity of contraction in the diseased state to that in the healthy state will be forty-five to eighteen, or as two and a half to one. From hence it would appear, that if we had a criterion to determine the velocity of the arterial contractions, it would at the same time give us their strength, and thus be of more service in distinguishing diseases, than the knowledge of their frequency. As such a criterion cannot be had, the frequency of pulsation, the age of the patient being allowed for, will in some measure assist us to distinguish arterial strength from arterial debility, since in inflammatory diseases with strength the frequency seldom exceeds one hundred and eighteen or one hundred and twenty pulsations in a minute; unless under peculiar circumstance, as the great additional stimuli of wine or of external heat. 5. After a muscle or organ of sense has been excited into contraction, and the sensorial power ceases to act, the last situation or configuration of it continues; unless it be disturbed by the action of some antagonist fibres, or other extraneous power. Thus in weak or languid people, wherever they throw their limbs on their bed or sofa, there they lie, till another exertion changes their attitude; hence one kind of ocular spectra seems to be produced after looking at bright objects; thus when a fire-stick is whirled round in the night, there appears in the eye a complete circle of fire; the action or configuration of one part of the retina not ceasing before the return of the whirling fire. Thus if any one looks at the setting sun for a short time, and then covers his closed eyes with his hand, he will for many seconds of time perceive the image of the sun on his retina. A similar image of all other bodies would remain some time in the eye, but is effaced by the eternal change of the motions of the extremity of this nerve in our attention to other objects. See Sect. XVIII. 5. on Sleep. Hence the dark spots, and other ocular spectra, are more frequently attended to, and remain longer in the eyes of weak people, as after violent exercise, intoxication, or want of sleep. 6. A contraction of the fibres somewhat greater than usual introduces pleasurable sensation into the system, according to the fourth law of animal causation. Hence the pleasure in the beginning of drunkenness is owing to the increased action of the system from the stimulus of vinous spirit or of opium. If the contractions be still greater in energy or duration, painful sensations are introduced, as in consequence of great heat, or caustic applications, or fatigue. If any part of the system, which is used to perpetual activity, as the stomach, or heart, or the fine vessels of the skin, acts for a time with less energy, another kind of painful sensation ensues, which is called hunger, or faintness, or cold. This occurs in a less degree in the locomotive muscles, and is called wearysomeness. In the two former kinds of sensation there is an expenditure of sensorial power, in these latter there is an accumulation of it. 7. We have used the words exertion of sensorial power as a general term to express either irritation, sensation, volition, or association; that is, to express the activity or motion of the spirit of animation, at the time it produces the contractions of the fibrous parts of the system. It may be supposed that there may exist a greater or less mobility of the fibrous parts of our system, or a propensity to be stimulated into contraction by the greater or less quantity or energy of the spirit of animation; and that hence if the exertion of the sensorial power be in its natural state, and the mobility of the fibres be increased, the same quantity of fibrous contraction will be caused, as if the mobility of the fibres continues in its natural state, and the sensorial exertion be increased. Thus it may be conceived, that in diseases accompanied with strength, as in inflammatory fevers with arterial strength, that the cause of greater fibrous contraction, may exist in the increased mobility of the fibres, whose contractions are thence both more forceable and more frequent. And that in diseases attended with debility, as in nervous fevers, where the fibrous contractions are weaker, and more frequent, it may be conceived that the cause consists in a decrease of mobility of the fibres; and that those weak constitutions, which are attended with cold extremities and large pupils of the eyes, may possess less mobility of the contractile fibres, as well as less quantity of exertion of the spirit of animation. In answer to this mode of reasoning it may be sufficient to observe, that the contractile fibres consist of inert matter, and when the sensorial power is withdrawn, as in death, they possess no power of motion at all, but remain in their last state, whether of contraction or relaxation, and must thence derive the whole of this property from the spirit of animation. At the same time it is not improbable, that the moving fibres of strong people may possess a capability of receiving or containing a greater quantity of the spirit of animation than those of weak people. In every contraction of a fibre there is an expenditure of the sensorial power, or spirit of animation; and where the exertion of this sensorial power has been for some time increased, and the muscles or organs of sense have in consequence acted with greater energy, its propensity to activity is proportionally lessened; which is to be ascribed to the exhaustion or diminution of its quantity. On the contrary, where there has been less fibrous contraction than usual for a certain time, the sensorial power or spirit of animation becomes accumulated in the inactive part of the system. Hence vigour succeeds rest, and hence the propensity to action of all our organs of sense and muscles is in a state of perpetual fluctuation. The irritability for instance of the retina, that is, its quantity of sensorial power, varies every moment according to the brightness or obscurity of the object last beheld compared with the present one. The same occurs to our sense of heat, and to every part of our system, which is capable of being excited into action. When this variation of the exertion of the sensorial power becomes much and permanently above or beneath the natural quantity, it becomes a disease. If the irritative motions be too great or too little, it shews that the stimulus of external things affect this sensorial power too violently or too inertly. If the sensitive motions be too great or too little, the cause arises from the deficient or exuberant quantity of sensation produced in consequence of the motions of the muscular fibres or organs of sense; if the voluntary actions are diseased the cause is to be looked for in the quantity of volition produced in consequence of the desire or aversion occasioned by the painful or pleasurable sensations above mentioned. And the diseases of associations probably depend on the greater or less quantity of the other three sensorial powers by which they were formed. From whence it appears that the propensity to action, whether it be called irritability, sensibility, voluntarity, or associability, is only another mode of expression for the quantity of sensorial power residing in the organ to be excited. And that on the contrary the words inirritability and insensibility, together with inaptitude to voluntary and associate motions, are synonymous with deficiency of the quantity of sensorial power, or of the spirit of animation, residing in the organs to be excited. II. _Of sensorial Exertion._ 1. There are three circumstances to be attended to in the production of animal motions, 1st. The stimulus. 2d. The sensorial power. 3d. The contractile fibre. 1st. A stimulus, external to the organ, originally induces into action the sensorial faculty termed irritation; this produces the contraction of the fibres, which, if it be perceived at all, introduces pleasure or pain; which in their active state are termed sensation; which is another sensorial faculty, and occasionally produces contraction of the fibres; this pleasure or pain is therefore to be considered as another stimulus, which may either act alone or in conjunction with the former faculty of the sensorium termed irritation. This new stimulus of pleasure or pain either induces into action the sensorial faculty termed sensation, which then produces the contraction of the fibres; or it introduces desire or aversion, which excite into action another sensorial faculty, termed volition, and may therefore be considered as another stimulus, which either alone or in conjunction with one or both of the two former faculties of the sensorium produces the contraction of animal fibres. There is another sensorial power, that of association, which perpetually, in conjunction with one or more of the above, and frequently singly, produces the contraction of animal fibres, and which is itself excited into action by the previous motions of contracting fibres. Now as the sensorial power, termed irritation, residing in any particular fibres, is excited into exertion by the stimulus of external bodies acting on those fibres; the sensorial power, termed sensation, residing in any particular fibres is excited into exertion by the stimulus of pleasure or pain acting on those fibres; the sensorial power, termed volition, residing in any particular fibres is excited into exertion by the stimulus of desire or aversion; and the sensorial power, termed association, residing in any particular fibres, is excited into action by the stimulus of other fibrous motions, which had frequently preceded them. The word stimulus may therefore be used without impropriety of language, for any of these four causes, which excite the four sensorial powers into exertion. For though the immediate cause of volition has generally been termed _a motive_; and that of irritation only has generally obtained the name of _stimulus_; yet as the immediate cause, which excites the sensorial powers of sensation, or of association into exertion, have obtained no general name, we shall use the word stimulus for them all. Hence the quantity of motion produced in any particular part of the animal system will be as the quantity of stimulus and the quantity of sensorial power, or spirit of animation, residing in the contracting fibres. Where both these quantities are great, _strength_ is produced, when that word is applied to the motions of animal bodies. Where either of them is deficient, _weakness_ is produced, as applied to the motions of animal bodies. Now as the sensorial power, or spirit of animation, is perpetually exhausted by the expenditure of it in fibrous contractions, and is perpetually renewed by the secretion or production of it in the brain and spinal marrow, the quantity of animal strength must be in a perpetual state of fluctuation on this account; and if to this be added the unceasing variation of all the four kinds of stimulus above described, which produce the exertions of the sensorial powers, the ceaseless vicissitude of animal strength becomes easily comprehended. If the quantity of sensorial power remains the same, and the quantity of stimulus be lessened, a weakness of the fibrous contractions ensues, which may be denominated _debility from defect of stimulus_. If the quantity of stimulus remains the same, and the quantity of sensorial power be lessened, another kind of weakness ensues, which may be termed _debility from defect of sensorial power_; the former of these is called by Dr. Brown, in his Elements of Medicine, direct debility, and the latter indirect debility. The coincidence of some parts of this work with correspondent deductions in the Brunonian Elementa Medicina, a work (with some exceptions) of great genius, must be considered as confirmations of the truth of the theory, as they were probably arrived at by different trains of reasoning. Thus in those who have been exposed to cold and hunger there is a deficiency of stimulus. While in nervous fever there is a deficiency of sensorial power. And in habitual drunkards, in a morning before their usual potation, there is a deficiency both of stimulus and of sensorial power. While, on the other hand, in the beginning of intoxication there is an excess of stimulus; in the hot-ach, after the hands have been immersed in snow, there is a redundancy of sensorial power; and in inflammatory diseases with arterial strength, there is an excess of both. Hence if the sensorial power be lessened, while the quantity of stimulus remains the same as in nervous fever, the frequency of repetition of the arterial contractions may continue, but their force in respect to removing obstacles, as in promoting the circulation of the blood, or the velocity of each contraction, will be diminished, that is, the animal strength will be lessened. And secondly, if the quantity of sensorial power be lessened, and the stimulus be increased to a certain degree, as in giving opium in nervous fevers, the arterial contractions may be performed more frequently than natural, yet with less strength. And thirdly, if the sensorial power continues the same in respect to quantity, and the stimulus be somewhat diminished, as in going into a darkish room, or into a coldish bath, suppose of about eighty degrees of heat, as Buxton-bath, a temporary weakness of the affected fibres is induced, till an accumulation of sensorial power gradually succeeds, and counterbalances the deficiency of stimulus, and then the bath ceases to feel cold, and the room ceases to appear dark; because the fibres of the subcutaneous vessels, or of the organs of sense, act with their usual energy. A set of muscular fibres may thus be stimulated into violent exertion, that is, they may act frequently, and with their whole sensorial power, but may nevertheless not act strongly; because the quantity of their sensorial power was originally small, or was previously exhausted. Hence a stimulus may be great, and the irritation in consequence act with its full force, as in the hot paroxysms of nervous fever; but if the sensorial power, termed irritation, be small in quantity, the force of the fibrous contractions, and the times of their continuance in their contracted state, will be proportionally small. In the same manner in the hot paroxysm of putrid fevers, which are shewn in Sect. XXXIII. to be inflammatory fevers with arterial debility, the sensorial power termed sensation is exerted with great activity, yet the fibrous contractions, which produce the circulation of the blood, are performed without strength, because the quantity of sensorial power then residing in that part of the system is small. Thus in irritative fever with arterial strength, that is, with excess of spirit of animation, the quantity of exertion during the hot part of the paroxysm is to be estimated from the quantity of stimulus, and the quantity of sensorial power. While in sensitive (or inflammatory) fever with arterial strength, that is, with excess of spirit of animation, the violent and forcible actions of the vascular system during the hot part of the paroxysm are induced by the exertions of two sensorial powers, which are excited by two kinds of stimulus. These are the sensorial power of irritation excited by the stimulus of bodies external to the moving fibres, and the sensorial power of sensation excited by the pain in consequence of the increased contractions of those moving fibres. And in insane people in some cases the force of their muscular actions will be in proportion to the quantity of sensorial power, which they possess, and the quantity of the stimulus of desire or aversion, which excites their volition into action. At the same time in other cases the stimulus of pain or pleasure, and the stimulus of external bodies, may excite into action the sensorial powers of sensation and irritation, and thus add greater force to their muscular actions. 2. The application of the stimulus, whether that stimulus be some quality of external bodies, or pleasure or pain, or desire or aversion, or a link of association, excites the correspondent sensorial power into action, and this causes the contraction of the fibre. On the contraction of the fibre a part of the spirit of animation becomes expended, and the fibre ceases to contract, though the stimulus continues to be applied; till in a certain time the fibre having received a supply of sensorial power is ready to contract again, if the stimulus continues to be applied. If the stimulus on the contrary be withdrawn, the same quantity of quiescent sensorial power becomes resident in the fibre as before its contraction; as appears from the readiness for action of the large locomotive muscles of the body in a short time after common exertion. But in those muscular fibres, which are subject to constant stimulus, as the arteries, glands, and capillary vessels, another phenomenon occurs, if their accustomed stimulus be withdrawn; which is, that the sensorial power becomes accumulated in the contractile fibres, owing to the want of its being perpetually expended, or carried away, by their usual unremitted contractions. And on this account those muscular fibres become afterwards excitable into their natural actions by a much weaker stimulus; or into unnatural violence of action by their accustomed stimulus, as is seen in the hot fits of intermittent fevers, which are in consequence of the previous cold ones. Thus the minute vessels of the skin are constantly stimulated by the fluid matter of heat; if the quantity of this stimulus of heat be a while diminished, as in covering the hands with snow, the vessels cease to act, as appears from the paleness of the skin; if this cold application of snow be continued but a short time, the sensorial power, which had habitually been supplied to the fibres, becomes now accumulated in them, owing to the want of its being expended by their accustomed contractions. And thence a less stimulus of heat will now excite them into violent contractions. If the quiescence of fibres, which had previously been subject to perpetual stimulus, continues a longer time; or their accustomed stimulus be more completely withdrawn; the accumulation of sensorial power becomes still greater, as in those exposed to cold and hunger; pain is produced, and the organ gradually dies from the chemical changes, which take place in it; or it is at a great distance of time restored to action by stimulus applied with great caution in small quantity, as happens to some larger animals and to many insects, which during the winter months lie benumbed with cold, and are said to sleep, and to persons apparently drowned, or apparently frozen to death. Snails have been said to revive by throwing them into water after having been many years shut up in the cabinets of the curious; and eggs and seeds in general are restored to life after many months of torpor by the stimulus of warmth and moisture. The inflammation of schirrous tumours, which have long existed in a state of inaction, is a process of this kind; as well as the sensibility acquired by inflamed tendons and bones, which had at their formation a similar sensibility, which had so long lain dormant in their uninflamed state. 3. If after long quiescence from defect of stimulus the fibres, which had previously been habituated to perpetual stimulus, are again exposed to but their usual quantity of it; as in those who have suffered the extremes of cold or hunger; a violent exertion of the affected organ commences, owing, as above explained, to the great accumulation of sensorial power. This violent exertion not only diminishes the accumulated spirit of animation, but at the same time induces pleasure or pain into the system, which, whether it be succeeded by inflammation or not, becomes an additional stimulus, and acting along with the former one, produces still greater exertions; and thus reduces the sensorial power in the contracting fibres beneath its natural quantity. When the spirit of animation is thus exhausted by useless exertions, the organ becomes torpid or unexcitable into action, and a second fit of quiescence succeeds that of abundant activity. During this second fit of quiescence the sensorial power becomes again accumulated, and another fit of exertion follows in train. These vicissitudes of exertion and inertion of the arterial system constitute the paroxysms of remittent fevers; or intermittent ones, when there is an interval of the natural action of the arteries between the exacerbations. In these paroxysms of fevers, which consist of the libration of the arterial system between the extremes of exertion and quiescence, either the fits become less and less violent from the contractile fibres becoming coming less excitable to the stimulus by habit, that is, by becoming accustomed to it, as explained below XII. 3. 1. or the whole sensorial power becomes exhausted, and the arteries cease to beat, and the patient dies in the cold part of the paroxysm. Or secondly, so much pain is introduced into the system by the violent contractions of the fibres, that inflammation arises, which prevents future cold fits by expending a part of the sensorial power in the extension of old vessels or the production of new ones; and thus preventing the too great accumulation or exertion of it in other parts of the system; or which by the great increase of stimulus excites into great action the whole glandular system as well as the arterial, and thence a greater quantity of sensorial power is produced in the brain, and thus its exhaustion in any peculiar part of the system ceases to be affected. 4. Or thirdly, in consequence of the painful or pleasurable sensation above mentioned, desire and aversion are introduced, and inordinate volition succeeds; which by its own exertions expends so much of the spirit of animation, that the two other sensorial faculties, or irritation and sensation, act so much more feebly; that the paroxysms of fever, or that libration between the extremes of exertion and inactivity of the arterial system, gradually subsides. On this account a temporary insanity is a favourable sign in fevers, as I have had some opportunities of observing. III. _Of repeated Stimulus._ 1. When a stimulus is repeated more frequently than the expenditure of sensorial power can be renewed in the acting organ, the effect of the stimulus becomes gradually diminished. Thus if two grains of opium be swallowed by a person unused to so strong a stimulus, all the vascular systems in the body act with greater energy, all the secretions and the absorption from those secreted fluids are increased in quantity; and pleasure or pain are introduced into the system, which adds an additional stimulus to that already too great. After some hours the sensorial power becomes diminished in quantity, expended by the great activity of the system; and thence, when the stimulus of the opium is withdrawn, the fibres will not obey their usual degree of natural stimulus, and a consequent torpor or quiescence succeeds, as is experienced by drunkards, who on the day after a great excess of spirituous potation feel indigestion, head-ach, and general debility. In this fit of torpor or quiescence of a part or of the whole of the system, an accumulation of the sensorial power in the affected fibres is formed, and occasions a second paroxysm of exertion by the application only of the natural stimulus, and thus a libration of the sensorial exertion between one excess and the other continues for two or three days, where the stimulus was violent in degree; and for weeks in some fevers, from the stimulus of contagious matter. But if a second dose of opium be exhibited before the fibres have regained their natural quantity of sensorial power, its effect will be much less than the former, because the spirit of animation or sensorial power is in part exhausted by the previous excess of exertion. Hence all medicines repeated too frequently gradually lose their effect, as opium and wine. Many things of disagreeable taste at first cease to be disagreeable by frequent repetition, as tobacco; grief and pain gradually diminish, and at length cease altogether, and hence life itself becomes tolerable. Besides the temporary diminution of the spirit of animation or sensorial power, which is naturally stationary or resident in every living fibre, by a single exhibition of a powerful stimulus, the contractile fibres themselves, by the perpetual application of a new quantity of stimulus, before they have regained their natural quantity of sensorial power, appear to suffer in their capability of receiving so much as the natural quantity of sensorial power; and hence a permanent deficiency of spirit of animation takes place, however long the stimulus may have been withdrawn. On this cause depends the permanent debility of those, who have been addicted to intoxication, the general weakness of old age, and the natural debility or inirritability of those, who have pale skins and large pupils of their eyes. There is a curious phenomenon belongs to this place, which has always appeared difficult of solution; and that is, that opium or aloes may be exhibited in small doses at first, and gradually increased to very large ones without producing stupor or diarrhoea. In this case, though the opium and aloes are given in such small doses as not to produce intoxication or catharsis, yet they are exhibited in quantities sufficient in some degree to exhaust the sensorial power, and hence a stronger and a stronger dose is required; otherwise the medicine would soon cease to act at all. On the contrary, if the opium or aloes be exhibited in a large dose at first, so as to produce intoxication or diarrhoea; after a few repetitions the quantity of either of them may be diminished, and they will still produce this effect. For the more powerful stimulus dissevers the progressive catenations of animal motions, described in Sect. XVII. and introduces a new link between them; whence every repetition strengthens this new association or catenation, and the stimulus may be gradually decreased, or be nearly withdrawn, and yet the effect shall continue; because the sensorial power of association or catenation being united with the stimulus, increases in energy with every repetition of the catenated circle; and it is by these means that all the irritative associations of motions are originally produced. 2. When a stimulus is repeated at such distant intervals of time, that the natural quantity of sensorial power becomes completely restored in the acting fibres, it will act with the same energy as when first applied. Hence those who have lately accustomed themselves to large doses of opium by beginning with small ones, and gradually increasing them, and repeating them frequently, as mentioned in the preceding paragraph; if they intermit the use of it for a few days only, must begin again with as small doses as they took at first, otherwise they will experience the inconveniences of intoxication. On this circumstance depend the constant unfailing effects of the various kinds of stimulus, which excite into action all the vascular systems in the body; the arterial, venous, absorbent, and glandular vessels, are brought into perpetual unwearied action by the fluids, which are adapted to stimulate them; but these have the sensorial power of association added to that of irritation, and even in some degree that of sensation, and even of volition, as will be spoken of in their places; and life itself is thus carried on by the production of sensorial power being equal to its waste or expenditure in the perpetual movement of the vascular organization. 3. When a stimulus is repeated at uniform intervals of time with such distances between them, that the expenditure of sensorial power in the acting fibres becomes completely renewed, the effect is produced with greater facility or energy. For the sensorial power of association is combined with the sensorial power of irritation, or, in common language, the acquired habit assists the power of the stimulus. This circumstance not only obtains in the annual and diurnal catenations of animal motions explained in Sect. XXXVI. but in every less circle of actions or ideas, as in the burthen of a song, or the iterations of a dance; and constitutes the pleasure we receive from repetition and imitation; as treated of in Sect. XXII. 2. 4. When a stimulus has been many times repeated at uniform intervals, so as to produce the complete action of the organ, it may then be gradually diminished, or totally withdrawn, and the action of the organ will continue. For the sensorial power of association becomes united with that of irritation, and by frequent repetition becomes at length of sufficient energy to carry on the new link in the circle of actions, without the irritation which at first introduced it. Hence, when the bark is given at stated intervals for the cure of intermittent fevers, if sixty grains of it be given every three hours for the twenty-four hours preceding the expected paroxysm, so as to stimulate the defective part of the system into action, and by that means to prevent the torpor or quiescence of the fibres, which constitutes the cold fit; much less than half the quantity, given before the time at which another paroxysm of quiescence would have taken place, will be sufficient to prevent it; because now the sensorial power, termed association, acts in a twofold manner. First, in respect to the period of the catenation in which the cold fit was produced, which is now dissevered by the stronger stimulus of the first doses of the bark; and, secondly, because each dose of bark being repeated at periodical times, has its effect increased by the sensorial faculty of association being combined with that of irritation. Now, when sixty grains of Peruvian bark are taken twice a day, suppose at ten o'clock and at six, for a fortnight, the irritation excited by this additional stimulus becomes a part of the diurnal circle of actions, and will at length carry on the increased action of the system without the assistance of the stimulus of the bark. On this theory the bitter medicines, chalybeates, and opiates in appropriated doses, exhibited for a fortnight, give permanent strength to pale feeble children, and other weak constitutions. 5. When a defect of stimulus, as of heat, recurs at certain diurnal intervals, which induces some torpor or quiescence of a part of the system, the diurnal catenation of actions becomes disordered, and a new association with this link of torpid action is formed; on the next period the quantity of quiescence will be increased, suppose the same defect of stimulus to recur, because now the new association conspires with the defective irritation in introducing the torpid action of this part of the diurnal catenation. In this manner many fever-fits commence, where the patient is for some days indisposed at certain hours, before the cold paroxysm of fever is completely formed. See Sect. XVII. 3. 3. on Catenation of Animal Motions. 6. If a stimulus, which at first excited the affected organ into so great exertion as to produce sensation, be continued for a certain time, it will cease to produce sensation both then and when repeated, though the irritative motions in consequence of it may continue or be re-excited. Many catenations of irritative motions were at first succeeded by sensation, as the apparent motions of objects when we walk past them, and probably the vital motions themselves in the early state of our existence. But as those sensations were followed by no movements of the system in consequence of them, they gradually ceased to be produced, not being joined to any succeeding link of catenation. Hence contagious matter, which has for some weeks stimulated the system into great and permanent sensation, ceases afterwards to produce general sensation, or inflammation, though it may still induce topical irritations. See Sect. XXXIII. 2. 8. XIX. 9. Our absorbent system then seems to receive those contagious matters, which it has before experienced, in the same manner as it imbibes common moisture or other fluids; that is, without being thrown into so violent action as to produce sensation; the consequence of which is an increase of daily energy or activity, till inflammation and its consequences succeed. 7. If a stimulus excites an organ into such violent contractions as to produce sensation, the motions of which organ had not usually produced sensation, this new sensorial power, added to the irritation occasioned by the stimulus, increases the activity of the organ. And if this activity be catenated with the diurnal circle of actions, an increasing inflammation is produced; as in the evening paroxysms of small-pox, and other fevers with inflammation. And hence schirrous tumours, tendons and membranes, and probably the arteries themselves become inflamed, when they are strongly stimulated. IV. _Of Stimulus greater than natural._ 1. A quantity of stimulus greater than natural, producing an increased exertion of sensorial power, whether that exertion be in the mode of irritation, sensation, volition, or association, diminishes the general quantity of it. This fact is observable in the progress of intoxication, as the increased quantity or energy of the irritative motions, owing to the stimulus of vinous spirit, introduces much pleasurable sensation into the system, and much exertion of muscular or sensual motions in consequence of this increased sensation; the voluntary motions, and even the associate ones, become much impaired or diminished; and delirium and staggering succeed. See Sect. XXI. on Drunkenness. And hence the great prostration of the strength of the locomotive muscles in some fevers, is owing to the exhaustion of sensorial power by the increased action of the arterial system. In like manner a stimulus greater than natural, applied to a part of the system, increases the exertion of sensorial power in that part, and diminishes it in some other part. As in the commencement of scarlet fever, it is usual to see great redness and heat on the faces and breasts of children, while at the same time their feet are colder than natural; partial heats are observable in other fevers with debility, and are generally attended with torpor or quiescence of some other part of the system. But these partial exertions of sensorial power are sometimes attended with increased partial exertions in other parts of the system, which sympathize with them, as the flushing of the face after a full meal. Both these therefore are to be ascribed to sympathetic associations, explained in Sect. XXXV. and not to general exhaustion or accumulation of sensorial power. 2. A quantity of stimulus greater than natural, producing an increased exertion of sensorial power in any particular organ, diminishes the quantity of it in that organ. This appears from the contractions of animal fibres being not so easily excited by a less stimulus after the organ has been subjected to a greater. Thus after looking at any luminous object of a small size, as at the setting sun, for a short time, so as not much to fatigue the eye, this part of the retina becomes less sensible to smaller quantities of light; hence when the eyes are turned on other less luminous parts of the sky, a dark spot is seen resembling the shape of the sun, or other luminous object which we last behold. See Sect. XL. No. 2. Thus we are some time before we can distinguish objects in an obscure room after coming from bright day-light, though the iris presently contracts itself. We are not able to hear weak sounds after loud ones. And the stomachs of those who have been much habituated to the stronger stimulus of fermented or spirituous liquors, are not excited into due action by weaker ones. 3. A quantity of stimulus something greater than the last mentioned, or longer continued, induces the organ into spasmodic action, which ceases and recurs alternately. Thus on looking for a time on the setting sun, so as not greatly to fatigue the sight, a yellow spectrum is seen when the eyes are closed and covered, which continues for a time, and then disappears and recurs repeatedly before it entirely vanishes. See Sect. XL. No. 5. Thus the action of vomiting ceases and is renewed by intervals, although the emetic drug is thrown up with the first effort. A tenesmus continues by intervals some time after the exclusion of acrid excrement; and the pulsations of the heart of a viper are said to continue some time after it is cleared from its blood. In these cases the violent contractions of the fibres produce pain according to law 4; and this pain constitutes an additional kind or quantity of excitement, which again induces the fibres into contraction, and which painful excitement is again renewed, and again induces contractions of the fibres with gradually diminishing effect. 4. A quantity of stimulus greater than that last mentioned, or longer continued, induces the antagonist muscles into spasmodic action. This is beautifully illustrated by the ocular spectra described in Sect. XL. No. 6. to which the reader is referred. From those experiments there is reason to conclude that the fatigued part of the retina throws itself into a contrary mode of action like oscitation or pandiculation, as soon as the stimulus, which has fatigued it, is withdrawn; but that it still remains liable to be excited into action by any other colours except the colour with which it has been fatigued. Thus the yawning and stretching the limbs after a continued action or attitude seems occasioned by the antagonist muscles being stimulated by their extension during the contractions of those in action, or in the situation in which that action last left them. 5. A quantity of stimulus greater than the last, or longer continued, induces variety of convulsions or fixed spasms either of the affected organ or of the moving fibres in the other parts of the body. In respect to the spectra in the eye, this is well illustrated in No. 7 and 8, of Sect. XL. Epileptic convulsions, as the emprosthotonos and opisthotonos, with the cramp of the calf of the leg, locked jaw, and other cataleptic fits, appear to originate from pain, as some of these patients scream aloud before the convulsion takes place; which seems at first to be an effort to relieve painful sensation, and afterwards an effort to prevent it. In these cases the violent contractions of the fibres produce so much pain, as to constitute a perpetual excitement; and that in so great a degree as to allow but small intervals of relaxation of the contracting fibres as in convulsions, or no intervals at all as in fixed spasms. 6. A quantity of stimulus greater than the last, or longer continued, produces a paralysis of the organ. In many cases this paralysis is only a temporary effect, as on looking long on a small area of bright red silk placed on a sheet of white paper on the floor in a strong light, the red silk gradually becomes paler, and at length disappears; which evinces that a part of the retina, by being violently excited, becomes for a time unaffected by the stimulus of that colour. Thus cathartic medicines, opiates, poisons, contagious matter, cease to influence our system after it has been habituated to the use of them, except by the exhibition of increased quantities of them; our fibres not only become unaffected by stimuli, by which they have previously been violently irritated, as by the matter of the small-pox or measles; but they also become unaffected by sensation, where the violent exertions, which disabled them, were in consequence of too great quantity of sensation. And lastly the fibres, which become disobedient to volition, are probably disabled by their too violent exertions in consequence of too great a quantity of volition. After every exertion of our fibres a temporary paralysis succeeds, whence the intervals of all muscular contractions, as mentioned in No. 3 and 4 of this Section; the immediate cause of these more permanent kinds of paralysis is probably owing in the same manner to the too great exhaustion of the spirit of animation in the affected part; so that a stronger stimulus is required, or one of a different kind from that, which occasioned those too violent contractions, to again excite the affected organ into activity; and if a stronger stimulus could be applied, it must again induce paralysis. For these powerful stimuli excite pain at the same time, that they produce irritation; and this pain not only excites fibrous motions by its stimulus, but it also produces volition; and thus all these stimuli acting at the same time, and sometimes with the addition of their associations, produce so great exertion as to expend the whole of the sensorial power in the affected fibres. V. _Of Stimulus less than natural._ 1. A quantity of stimulus less than natural, producing a decreased exertion of sensorial power, occasions an accumulation of the general quantity of it. This circumstance is observable in the hemiplagia, in which the patients are perpetually moving the muscles, which are unaffected. On this account we awake with greater vigour after sleep, because during so many hours, the great usual expenditure of sensorial power in the performance of voluntary actions, and in the exertions of our organs of sense, in consequence of the irritations occasioned by external objects had been suspended, and a consequent accumulation had taken place. In like manner the exertion of the sensorial power less than natural in one part of the system, is liable to produce an increase of the exertion of it in some other part. Thus by the action of vomiting, in which the natural exertion of the motions of the stomach are destroyed or diminished, an increased absorption of the pulmonary and cellular lymphatics is produced, as is known by the increased absorption of the fluid deposited in them in dropsical cases. But these partial quiescences of sensorial power are also sometimes attended with other partial quiescences, which sympathize with them, as cold and pale extremities from hunger. These therefore are to be ascribed to the associations of sympathy explained in Sect. XXXV. and not to the general accumulation of sensorial power. 2. A quantity of stimulus less than natural, applied to fibres previously accustomed to perpetual stimulus, is succeeded by accumulation of sensorial power in the affected organ. The truth of this proposition is evinced, because a stimulus less than natural, if it be somewhat greater than that above mentioned, will excite the organ so circumstanced into violent activity. Thus on a frosty day with wind, the face of a person exposed to the wind is at first pale and shrunk; but on turning the face from the wind, it becomes soon of a glow with warmth and flushing. The glow of the skin in emerging from the cold-bath is owing to the same cause. It does not appear, that an accumulation of sensorial power above the natural quantity is acquired by those muscles, which are not subject to perpetual stimulus, as the locomotive muscles: these, after the greatest fatigue, only acquire by rest their usual aptitude to motion; whereas the vascular system, as the heart and arteries, after a short quiescence, are thrown into violent action by their natural quantity of stimulus. Nevertheless by this accumulation of sensorial power during the application of decreased stimulus, and by the exhaustion of it during the action of increased stimulus, it is wisely provided, that the actions of the vascular muscles and organs of sense are not much deranged by small variations of stimulus; as the quantity of sensorial power becomes in some measure inversely as the quantity of stimulus. 3. A quantity of stimulus less than that mentioned above, and continued for some time, induces pain in the affected organ, as the pain of cold in the hands, when they are immersed in snow, is owing to a deficiency of the stimulation of heat. Hunger is a pain from the deficiency of the stimulation of food. Pain in the back at the commencement of ague-fits, and the head-achs which attend feeble people, are pains from defect of stimulus, and are hence relieved by opium, essential oils, spirit of wine. As the pains, which originate from defect of stimulus, only occur in those parts of the system, which have been previously subjected to perpetual stimulus; and as an accumulation of sensorial power is produced in the quiescent organ along with the pain, as in cold or hunger, there is reason to believe, that the pain is owing to the accumulation of sensorial power. For, in the locomotive muscles, in the retina of the eye, and other organs of senses, no pain occurs from the absence of stimulus, nor any great accumulation of sensorial power beyond their natural quantity, since these organs have not been used to a perpetual supply of it. There is indeed a greater accumulation occurs in the organ of vision after its quiescence, because it is subject to more constant stimulus. 4. A certain quantity of stimulus less than natural induces the moving organ into feebler and more frequent contractions, as mentioned in No. I. 4. of this Section. For each contraction moving through a less space, or with less force, that is, with less expenditure of the spirit of animation, is sooner relaxed, and the spirit of animation derived at each interval into the acting fibres being less, these intervals likewise become shorter. Hence the tremours of the hands of people accustomed to vinous spirit, till they take their usual stimulus; hence the quick pulse in fevers attended with debility, which is greater than in fevers attended with strength; in the latter the pulse seldom beats above 120 times in a minute, in the former it frequently exceeds 140. It must be observed, that in this and the two following articles the decreased action of the system is probably more frequently occasioned by deficiency in the quantity of sensorial power, than in the quantity of stimulus. Thus those feeble constitutions which have large pupils of their eyes, and all who labour under nervous fevers, seem to owe their want of natural quantity of activity in the system to the deficiency of sensorial power; since, as far as can be seen, they frequently possess the natural quantity of stimulus. 5. A certain quantity of stimulus, less than that above mentioned, inverts the order of successive fibrous contractions; as in vomiting the vermicular motions of the stomach and duodenum are inverted, and their contents ejected, which is probably owing to the exhaustion of the spirit of animation in the acting muscles by a previous excessive stimulus, as by the root of ipecacuanha, and the consequent defect of sensorial power. The same retrograde motions affect the whole intestinal canal in ileus; and the oesophagus in globus hystericus. See this further explained in Sect. XXIX. No. 11. on Retrograde Motions. I must observe, also, that something similar happens in the production of our ideas, or sensual motions, when they are too weakly excited; when any one is thinking intensely about one thing, and carelessly conversing about another, he is liable to use the word of a contrary meaning to that which he designed, as cold weather for hot weather, summer for winter. 6. A certain quantity of stimulus, less than that above mentioned, is succeeded by paralysis, first of the voluntary and sensitive motions, and afterwards of those of irritation, and of association, which constitutes death. VI. _Cure of increased Exertion._ 1. The cure, which nature has provided for the increased exertion of any part of the system, consists in the consequent expenditure of the sensorial power. But as a greater torpor follows this exhaustion of sensorial power, as explained in the next paragraph, and a greater exertion succeeds this torpor, the constitution frequently sinks under these increasing librations between exertion and quiescence; till at length complete quiescence, that is, death, closes the scene. For, during the great exertion of the system in the hot fit of fever, an increase of stimulus is produced from the greater momentum of the blood, the greater distention of the heart and arteries, and the increased production of heat, by the violent actions of the system occasioned by this augmentation of stimulus, the sensorial power becomes diminished in a few hours much beneath its natural quantity, the vessels at length cease to obey even these great degrees of stimulus, as shewn in Sect. XL. 9. 1. and a torpor of the whole or of a part of the system ensues. Now as this second cold fit commences with a greater deficiency of sensorial power, it is also attended with a greater deficiency of stimulus than in the preceding cold fit, that is, with less momentum of blood, less distention of the heart. On this account the second cold fit becomes more violent and of longer duration than the first; and as a greater accumulation of sensorial power must be produced before the system of vessels will again obey the diminished stimulus, it follows, that the second hot fit of fever will be more violent than the former one. And that unless some other causes counteract either the violent exertions in the hot fit, or the great torpor in the cold fit, life will at length be extinguished by the expenditure of the whole of the sensorial power. And from hence it appears, that the true means of curing fevers must be such as decrease the action of the system in the hot fit, and increase it in the cold fit; that is, such as prevent the too great diminution of sensorial power in the hot fit, and the too great accumulation of it in the cold one. 2. Where the exertion of the sensorial powers is much increased, as in the hot fits of fever or inflammation, the following are the usual means of relieving it. Decrease the irritations by blood-letting, and other evacuations; by cold water taken into the stomach, or injected as an enema, or used externally; by cold air breathed into the lungs, and diffused over the skin; with food of less stimulus than the patient has been accustomed to. 3. As a cold fit, or paroxysm of inactivity of some parts of the system, generally precedes the hot fit, or paroxysm of exertion, by which the sensorial power becomes accumulated, this cold paroxysm should be prevented by stimulant medicines and diet, as wine, opium, bark, warmth, cheerfulness, anger, surprise. 4. Excite into greater action some other part of the system, by which means the spirit of animation may be in part expended, and thence the inordinate actions of the diseased part may be lessened. Hence when a part of the skin acts violently, as of the face in the eruption of the small-pox, if the feet be cold they should be covered. Hence the use of a blister applied near a topical inflammation. Hence opium and warm bath relieve pains both from excess and defect of stimulus. 5. First increase the general stimulation above its natural quantity, which may in some degree exhaust the spirit of animation, and then decrease the stimulation beneath its natural quantity. Hence after sudorific medicines and warm air, the application of refrigerants may have greater effect, if they could be administered without danger of producing too great torpor of some part of the system; as frequently happens to people in health from coming out of a warm room into the cold air, by which a topical inflammation in consequence of torpor of the mucous membrane of the nostril is produced, and is termed a cold in the head. VII. _Cure of decreased Exertion._ 1. Where the exertion of the sensorial powers is much decreased, as in the cold fits of fever, a gradual accumulation of the spirit of animation takes place; as occurs in all cases where inactivity or torpor of a part of the system exists; this accumulation of sensorial power increases, till stimuli less than natural are sufficient to throw it into action, then the cold fit ceases; and from the action of the natural stimuli a hot one succeeds with increased activity of the whole system. So in fainting fits, or syncope, there is a temporary deficiency of sensorial exertion, and a consequent quiescence of a great part of the system. This quiescence continues, till the sensorial power becomes again accumulated in the torpid organs; and then the usual diurnal stimuli excite the revivescent parts again into action; but as this kind of quiescence continues but a short time compared to the cold paroxysm of an ague, and less affects the circulatory system, a less superabundancy of exertion succeeds in the organs previously torpid, and a less excess of arterial activity. See Sect. XXXIV. 1. 6. 2. In the diseases occasioned by a defect of sensorial exertion, as in cold fits of ague, hysteric complaint, and nervous fever, the following means are those commonly used. 1. Increase the stimulation above its natural quantity for some weeks, till a new habit of more energetic contraction of the fibres is established. This is to be done by wine, opium, bark, steel, given at exact periods, and in appropriate quantities; for if these medicines be given in such quantity, as to induce the least degree of intoxication, a debility succeeds from the useless exhaustion of spirit of animation in consequence of too great exertion of the muscles or organs of sense. To these irritative stimuli should be added the sensitive ones of cheerful ideas, hope, affection. 3. Change the kinds of stimulus. The habits acquired by the constitution depend on such nice circumstances, that when one kind of stimulus ceases to excite the sensorial power into the quantity of exertion necessary to health, it is often sufficient to change the stimulus for another apparently similar in quantity and quality. Thus when wine ceases to stimulate the constitution, opium in appropriate doses supplies the defect; and the contrary. This is also observed in the effects of cathartic medicines, when one loses its power, another, apparently less efficacious, will succeed. Hence a change of diet, drink, and stimulating medicines, is often advantageous in diseases of debility. 4. Stimulate the organs, whose motions are associated with the torpid parts of the system. The actions of the minute vessels of the various parts of the external skin are not only associated with each other, but are strongly associated with those of some of the internal membranes, and particularly of the stomach. Hence when the exertion of the stomach is less than natural, and indigestion and heartburn succeed, nothing so certainly removes these symptoms as the stimulus of a blister on the back. The coldness of the extremities, as of the nose, ears, or fingers, are hence the best indication for the successful application of blisters. 5. Decrease the stimulus for a time. By lessening the quantity of heat for a minute or two by going into the cold bath, a great accumulation of sensorial power is produced; for not only the minute vessels of the whole external skin for a time become inactive, as appears by their paleness; but the minute vessels of the lungs lose much of their activity also by concert with those of the skin, as appears from the difficulty of breathing at first going into cold water. On emerging from the bath the sensorial power is thrown into great exertion by the stimulus of the common degree of the warmth of the atmosphere, and a great production of animal heat is the consequence. The longer a person continues in the cold bath the greater must be the present inertion of a great part of the system, and in consequence a greater accumulation of sensorial power. Whence M. Pomè recommends some melancholy patients to be kept from two to six hours in spring-water, and in baths still colder. 6. Decrease the stimulus for a time below the natural, and then increase it above natural. The effect of this process, improperly used, is seen in giving much food, or applying much warmth, to those who have been previously exposed to great hunger, or to great cold. The accumulated sensorial power is thrown into so violent exertion, that inflammations and mortifications supervene, and death closes the catastrophe. In many diseases this method is the most successful; hence the bark in agues produces more certain effect after the previous exhibition of emetics. In diseases attended with violent pain, opium has double the effect, if venesection and a cathartic have been previously used. On this seems to have been founded the successful practice of Sydenham, who used venesection and a cathartic in chlorosis before the exhibition of the bark, steel, and opiates. 7. Prevent any unnecessary expenditure of sensorial power. Hence in fevers with debility, a decumbent posture is preferred, with silence, little light, and such a quantity of heat as may prevent any chill sensation, or any coldness of the extremities. The pulse of patients in fevers with debility increases in frequency above ten pulsations in a minute on their rising out of bed. For the expenditure of sensorial power to preserve an erect posture of the body adds to the general deficiency of it, and thus affects the circulation. 8. The longer in time and the greater in degree the quiescence or inertion of an organ has been, so that it still retains life or excitability, the less stimulus should at first be applied to it. The quantity of stimulation is a matter of great nicety to determine, where the torpor or quiescence of the fibres has been experienced in a great degree, or for a considerable time, as in cold fits of the ague, in continued fevers with great debility, or in people famished at sea, or perishing with cold. In the two last cases, very minute quantities of food should be first supplied, and very few additional degrees of heat. In the two former cases, but little stimulus of wine or medicine, above what they had been lately accustomed to, should be exhibited, and this at frequent and stated intervals, so that the effect of one quantity may be observed before the exhibition of another. If these circumstances are not attended to, as the sensorial power becomes accumulated in the quiescent fibres, an inordinate exertion takes place by the increase of stimulus acting on the accumulated quantity of sensorial power, and either the paralysis, or death of the contractile fibres ensues, from the total expenditure of the sensorial power in the affected organ, owing to this increase of exertion, like the debility after intoxication. Or, secondly, the violent exertions above mentioned produce painful sensation, which becomes a new stimulus, and by thus producing inflammation, and increasing the activity of the fibres already too great, sooner exhausts the whole of the sensorial power in the acting organ, and mortification, that is, the death of the part, supervenes. Hence there have been many instances of people, whose limbs have been long benumbed by exposure to cold, who have lost them by mortification on their being too hastily brought to the fire; and of others, who were nearly famished at sea, who have died soon after having taken not more than an usual meal of food. I have heard of two well-attested instances of patients in the cold fit of ague, who have died from the exhibition of gin and vinegar, by the inflammation which ensued. And in many fevers attended with debility, the unlimited use of wine, and the wanton application of blisters, I believe, has destroyed numbers by the debility consequent to too great stimulation, that is, by the exhaustion of the sensorial power by its inordinate exertion. Wherever the least degree of intoxication exists, a proportional debility is the consequence; but there is a golden rule by which the necessary and useful quantity of stimulus in fevers with debility may be ascertained. When wine or beer are exhibited either alone or diluted with water, if the pulse becomes slower the stimulus is of a proper quantity; and should be repeated every two or three hours, or when the pulse again becomes quicker. In the chronical debility brought on by drinking spirituous or fermented liquors, there is another golden rule by which I have successfully directed the quantity of spirit which they may safely lessen, for there is no other means by which they can recover their health. It should be premised, that where the power of digestion in these patients is totally destroyed, there is not much reason to expect a return to healthful vigour. I have directed several of these patients to omit one fourth part of the quantity of vinous spirit they have been lately accustomed to, and if in a fortnight their appetite increases, they are advised to omit another fourth part; but if they perceive that their digestion becomes impaired from the want of this quantity of spirituous potation, they are advised to continue as they are, and rather bear the ills they have, than risk the encounter of greater. At the same time flesh-meat with or without spice is recommended, with Peruvian bark and steel in small quantities between their meals, and half a grain of opium or a grain, with five or eight grains of rhubarb at night. * * * * * SECT. XIII. OF VEGETABLE ANIMATION. I. 1. _Vegetables are irritable; mimosa, dionæa muscipula. Vegetable secretions._ 2. _Vegetable buds are inferior animals, are liable to greater or less irritability._ II. _Stamens and pistils of plants shew marks of sensibility._ III. _Vegetables possess some degree of volition._ IV. _Motions of plants are associated like those of animals._ V. 1. _Vegetable structure like that of animals, their anthers and stigmas are living creatures. Male-flowers of Vallisneria._ 2. _Whether vegetables, possess ideas? They have organs of sense as of touch and smell, and ideas of external things?_ I. 1. The fibres of the vegetable world, as well as those of the animal, are excitable into a variety of motion by irritations of external objects. This appears particularly in the mimosa or sensitive plant, whose leaves contract on the slightest injury; the dionæa muscipula, which was lately brought over from the marshes of America, presents us with another curious instance of vegetable irritability; its leaves are armed with spines on their upper edge, and are spread on the ground around the stem; when an insect creeps on any of them in its passage to the flower or seed, the leaf shuts up like a steel rat-trap, and destroys its enemy. See Botanic Garden, Part II. note on Silene. The various secretions of vegetables, as of odour, fruit, gum, resin, wax, honey, seem brought about in the same manner as in the glands of animals; the tasteless moisture of the earth is converted by the hop-plant into a bitter juice; as by the caterpillar in the nut-shell the sweet kernel is converted into a bitter powder. While the power of absorption in the roots and barks of vegetables is excited into action by the fluids applied to their mouths like the lacteals and lymphatics of animals. 2. The individuals of the vegetable world may be considered as inferior or less perfect animals; a tree is a congeries of many living buds, and in this respect resembles the branches of coralline, which are a congeries of a multitude of animals. Each of these buds of a tree has its proper leaves or petals for lungs, produces its viviparous or its oviparous offspring in buds or seeds; has its own roots, which extending down the stem of the tree are interwoven with the roots of the other buds, and form the bark, which is the only living part of the stem, is annually renewed, and is superinduced upon the former bark, which then dies, and with its stagnated juices gradually hardening into wood forms the concentric circles, which we see in blocks of timber. The following circumstances evince the individuality of the buds of trees. First, there are many trees, whose whole internal wood is perished, and yet the branches are vegete and healthy. Secondly, the fibres of the barks of trees are chiefly longitudinal, resembling roots, as is beautifully seen in those prepared barks, that were lately brought from Otaheita. Thirdly, in horizontal wounds of the bark of trees, the fibres of the upper lip are always elongated downwards like roots, but those of the lower lip do not approach to meet them. Fourthly, if you wrap wet moss round any joint of a vine, or cover it with moist earth, roots will shoot out from it. Fifthly, by the inoculation or engrafting of trees many fruits are produced from one stem. Sixthly, a new tree is produced from a branch plucked from an old one, and set in the ground. Whence it appears that the buds of deciduous trees are so many annual plants, that the bark is a contexture of the roots of each individual bud; and that the internal wood is of no other use but to support them in the air, and that thus they resemble the animal world in their individuality. The irritability of plants, like that of animals, appears liable to be increased or decreased by habit; for those trees or shrubs, which are brought from a colder climate to a warmer, put out their leaves and blossoms a fortnight sooner than the indigenous ones. Professor Kalm, in his Travels in New York, observes that the apple-trees brought from England blossom a fortnight sooner than the native ones. In our country the shrubs, that are brought a degree or two from the north, are observed to flourish better than those, which come from the south. The Siberian barley and cabbage are said to grow larger in this climate than the similar more southern vegetables. And our hoards of roots, as of potatoes and onions, germinate with less heat in spring, after they have been accustomed to the winter's cold, than in autumn after the summer's heat. II. The stamens and pistils of flowers shew evident marks of sensibility, not only from many of the stamens and some pistils approaching towards each other at the season of impregnation, but from many of them closing their petals and calyxes during the cold parts of the day. For this cannot be ascribed to irritation, because cold means a defect of the stimulus of heat; but as the want of accustomed stimuli produces pain, as in coldness, hunger, and thirst of animals, these motions of vegetables in closing up their flowers must be ascribed to the disgreeable sensation, and not to the irritation of cold. Others close up their leaves during darkness, which, like the former, cannot be owing to irritation, as the irritating material is withdrawn. The approach of the anthers in many flowers to the stigmas, and of the pistils of some flowers to the anthers, must be ascribed to the passion of love, and hence belongs to sensation, not to irritation. III. That the vegetable world possesses some degree of voluntary powers, appears from their necessity to sleep, which we have shewn in Sect. XVIII. to consist in the temporary abolition of voluntary power. This voluntary power seems to be exerted in the circular movement of the tendrils of vines, and other climbing vegetables; or in the efforts to turn the upper surface of their leaves, or their flowers to the light. IV. The associations of fibrous motions are observable in the vegetable world, as well as in the animal. The divisions of the leaves of the sensitive plant have been accustomed to contract at the same time from the absence of light; hence if by any other circumstance, as a slight stroke or injury, one division is irritated into contraction, the neighbouring ones contract also, from their motions being associated with those of the irritated part. So the various stamina of the class of syngenesia have been accustomed to contract together in the evening, and thence if you stimulate one of them with a pin, according to the experiment of M. Colvolo, they all contract from their acquired associations. To evince that the collapsing of the sensitive plant is not owing to any mechanical vibrations propagated along the whole branch, when a single leaf is struck with the finger, a leaf of it was slit with sharp scissors, and some seconds of time passed before the plant seemed sensible of the injury; and then the whole branch collapsed as far as the principal stem: this experiment was repeated several times with the least possible impulse to the plant. V. 1. For the numerous circumstances in which vegetable buds are analogous to animals, the reader is referred to the additional notes at the end of the Botanic Garden, Part I. It is there shewn, that the roots of vegetables resemble the lacteal system of animals; the sap-vessels in the early spring, before their leaves expand, are analogous to the placental vessels of the foetus; that the leaves of land-plants resemble lungs, and those of aquatic plants the gills of fish; that there are other systems of vessels resembling the vena portarum of quadrupeds, or the aorta of fish; that the digestive power of vegetables is similar to that of animals converting the fluids, which they absorb, into sugar; that their seeds resemble the eggs of animals, and their buds and bulbs their viviparous offspring. And, lastly, that the anthers and stigmas are real animals, attached indeed to their parent tree like polypi or coral insects, but capable of spontaneous motion; that they are affected with the passion of love, and furnished with powers of reproducing their species, and are fed with honey like the moths and butterflies, which plunder their nectaries. See Botanic Garden, Part I. add. note XXXIX. The male flowers of vallisneria approach still nearer to apparent animality, as they detach themselves from the parent plant, and float on the surface of the water to the female ones. Botanic Garden, Part II. Art. Vallisneria. Other flowers of the classes of monecia and diecia, and polygamia, discharge the fecundating farina, which floating in the air is carried to the stigma of the female flowers, and that at considerable distances. Can this be effected by any specific attraction? or, like the diffusion of the odorous particles of flowers, is it left to the currents of winds, and the accidental miscarriages of it counteracted by the quantity of its production? 2. This leads us to a curious enquiry, whether vegetables have ideas of external things? As all our ideas are originally received by our senses, the question may be changed to, whether vegetables possess any organs of sense? Certain it is, that they possess a sense of heat and cold, another of moisture and dryness, and another of light and darkness; for they close their petals occasionally from the presence of cold, moisture, or darkness. And it has been already shewn, that these actions cannot be performed simply from irritation, because cold and darkness are negative quantities, and on that account sensation or volition are implied, and in consequence a sensorium or union of their nerves. So when we go into the light, we contract the iris; not from any stimulus of the light on the fine muscles of the iris, but from its motions being associated with the sensation of too much light on the retina: which could not take place without a sensorium or center of union of the nerves of the iris with those of vision. See Botanic Garden, Part I. Canto 3. l. 440. note. Besides these organs of sense, which distinguish cold, moisture, and darkness, the leaves of mimosa, and of dionæa, and of drosera, and the stamens of many flowers, as of the berbery, and the numerous class of syngenesia, are sensible to mechanic impact, that is, they possess a sense of touch, as well as a common sensorium; by the medium of which their muscles are excited into action. Lastly, in many flowers the anthers, when mature, approach the stigma, in others the female organ approaches to the male. In a plant of collinsonia, a branch of which is now before me, the two yellow stamens are about three eights of an inch high, and diverge from each other, at an angle of about fifteen degrees, the purple style is half an inch high, and in some flowers is now applied to the stamen on the right hand, and in others to that of the left; and will, I suppose, change place to-morrow in those, where the anthers have not yet effused their powder. I ask, by what means are the anthers in many flowers, and stigmas in other flowers, directed to find their paramours? How do either of them know, that the other exists in their vicinity? Is this curious kind of storge produced by mechanic attraction, or by the sensation of love? The latter opinion is supported by the strongest analogy, because a reproduction of the species is the consequence; and then another organ of sense must be wanted to direct these vegetable amourettes to find each other, one probably analogous to our sense of smell, which in the animal world directs the new-born infant to its source of nourishment, and they may thus possess a faculty of perceiving as well as of producing odours. Thus, besides a kind of taste at the extremities of their roots, similar to that of the extremities of our lacteal vessels, for the purpose of selecting their proper food: and besides different kinds of irritability residing in the various glands, which separate honey, wax, resin, and other juices from their blood; vegetable life seems to possess an organ of sense to distinguish the variations of heat, another to distinguish the varying degrees of moisture, another of light, another of touch, and probably another analogous to our sense of smell. To these must be added the indubitable evidence of their passion of love, and I think we may truly conclude, that they are furnished with a common sensorium belonging to each bud and that they must occasionally repeat those perceptions either in their dreams or waking hours, and consequently possess ideas of so many of the properties of the external world, and of their own existence. * * * * * SECT. XIV. OF THE PRODUCTION OF IDEAS. I. _Of material and immaterial beings. Doctrine of St. Paul._ II. 1. _Of the sense of touch. Of solidity._ 2. _Of figure. Motion. Time. Place. Space. Number._ 3. _Of the penetrability of matter._ 4. _Spirit of animation possesses solidity, figure, visibility, &c. Of Spirits and angels._ 5. _The existence of external things._ III. _Of vision._ IV. _Of hearing._ V. _Of smell and taste._ VI. _Of the organ of sense by which we perceive heat and cold, not by the sense of touch._ VII. _Of the sense of extension, the whole of the locomotive muscles may be considered as one organ of sense._ VIII. _Of the senses of hunger, thirst, want of fresh air, suckling children, and lust._ IX. _Of many other organs of sense belonging to the glands. Of painful sensations from the excess of light, pressure, heat, itching, caustics, and electricity._ I. Philosophers have been much perplexed to understand, in what manner we become acquainted with the external world; insomuch that Dr. Berkly even doubted its existence, from having observed (as he thought) that none of our ideas resemble their correspondent objects. Mr. Hume asserts, that our belief depends on the greater distinctness or energy of our ideas from perception; and Mr. Reid has lately contended, that our belief of external objects is an innate principle necessarily joined with our perceptions. So true is the observation of the famous Malbranch, "that our senses are not given us to discover the essences of things, but to acquaint us with the means of preserving our existence," (L. I. ch. v.) a melancholy reflection to philosophers! Some philosophers have divided all created beings into material and immaterial: the former including all that part of being, which obeys the mechanic laws of action and reaction, but which can begin no motion of itself; the other is the cause of all motion, and is either termed the power of gravity, or of specific attraction, or the spirit of animation. This immaterial agent is supposed to exist in or with matter, but to be quite distinct from it, and to be equally capable of existence, after the matter, which now possesses it, is decomposed. Nor is this theory ill supported by analogy, since heat, electricity, and magnetism, can be given to or taken from a piece of iron; and must therefore exist, whether separated from the metal, or combined with it. From a parity of reasoning, the spirit of animation, would appear to be capable of existing as well separately from the body as with it. I beg to be understood, that I do not wish to dispute about words, and am ready to allow, that the powers of gravity, specific attraction, electricity, magnetism, and even the spirit of animation, may consist of matter of a finer kind; and to believe, with St. Paul and Malbranch, that the ultimate cause only of all motion is immaterial, that is God. St. Paul says, "in him we live and move, and have our being;" and, in the 15th chapter to the Corinthians, distinguishes between the psyche or living spirit, and the pneuma or reviving spirit. By the words spirit of animation or sensorial power, I mean only that animal life, which mankind possesses in common with brutes, and in some degree even with vegetables, and leave the consideration of the immortal part of us, which is the object of religion, to those who treat of revelation. II. 1. _Of the Sense of Touch._ The first idea we become acquainted with, are those of the sense of touch; for the foetus must experience some varieties of agitation, and exert some muscular action, in the womb; and may with great probability be supposed thus to gain some ideas of its own figure, of that of the uterus, and of the tenacity of the fluid, that surrounds it, (as appears from the facts mentioned in the succeeding Section upon Instinct.) Many of the organs of sense are confined to a small part of the body, as the nostrils, ear, or eye, whilst the sense of touch is diffused over the whole skin, but exists with a more exquisite degree of delicacy at the extremities of the fingers and thumbs, and in the lips. The sense of touch is thus very commodiously disposed for the purpose of encompassing smaller bodies, and for adapting itself to the inequalities of larger ones. The figure of small bodies seems to be learnt by children by their lips as much as by their fingers; on which account they put every new object to their mouths, when they are satiated with food, as well as when they are hungry. And puppies seem to learn their ideas of figure principally by the lips in their mode of play. We acquire our tangible ideas of objects either by the simple pressure of this organ of touch against a solid body, or by moving our organ of touch along the surface of it. In the former case we learn the length and breadth of the object by the quantity of our organ of touch, that is impressed by it: in the latter case we learn the length and breadth of objects by the continuance of their pressure on our moving organ of touch. It is hence, that we are very slow in acquiring our tangible ideas, and very slow in recollecting them; for if I now think of the tangible idea of a cube, that is, if I think of its figure, and of the solidity of every part of that figure, I must conceive myself as passing my fingers over it, and seem in some measure to feel the idea, as I formerly did the impression, at the ends of them, and am thus very slow in distinctly recollecting it. When a body compresses any part of our sense of touch, what happens? First, this part of our sensorium undergoes a mechanical compression, which is termed a stimulus; secondly, an idea, or contraction of a part of the organ of sense is excited; thirdly, a motion of the central parts, or of the whole sensorium, which is termed sensation, is produced; and these three constitute the perception of solidity. 2. _Of Figure, Motion, Time, Place, Space, Number._ No one will deny, that the medulla of the brain and nerves has a certain figure; which, as it is diffused through nearly the whole of the body, must have nearly the figure of that body. Now it follows, that the spirit of animation, or living principle, as it occupies this medulla, and no other part, (which is evinced by a great variety of cruel experiments on living animals,) it follows, that this spirit of animation has also the same figure as the medulla above described. I appeal to common sense! the spirit of animation acts, Where does it act? It acts wherever there is the medulla above mentioned; and that whether the limb is yet joined to a living animal, or whether it be recently detached from it; as the heart of a viper or frog will renew its contractions, when pricked with a pin, for many minutes of time after its exsection from the body.--Does it act any where else?--No; then it certainly exists in this part of space, and no where else; that is, it hath figure; namely, the figure of the nervous system, which is nearly the figure of the body. When the idea of solidity is excited, as above explained, a part of the extensive organ of touch is compressed by some external body, and this part of the sensorium so compressed exactly resembles _in figure_ the figure of the body that compressed it. Hence, when we acquire the idea of solidity, we acquire at the same time the idea of FIGURE; and this idea of figure, or motion of _a part_ of the organ of touch, exactly resembles _in its figure_ the figure of the body that occasions it; and thus exactly acquaints us with this property of the external world. Now, as the whole universe with all its parts possesses a certain form or figure, if any part of it moves, that form or figure of the whole is varied: hence, as MOTION is no other than a perpetual variation of figure, our idea of motion is also a real resemblance of the motion that produced it. It may be said in objection to this definition of motion, that an ivory globe may revolve on its axis, and that here will be a motion without change of figure. But the figure of the particle _x_ on one side of this globe is not the _same_ figure as the figure of _y_ on the other side, any more than the particles themselves are the same, though they are _similar_ figures; and hence they cannot change place with each other without disturbing or changing the figure of the whole. Our idea of TIME is from the same source, but is more abstracted, as it includes only the comparative velocities of these variations of figure; hence if it be asked, How long was this book in printing? it may be answered, Whilst the sun was passing through Aries. Our idea of PLACE includes only the figure of a group of bodies, not the figures of the bodies themselves. If it be asked where is Nottinghamshire, the answer is, it is surrounded by Derbyshire, Lincolnshire and Leicestershire; hence place is our idea of the figure of one body surrounded by the figures of other bodies. The idea of SPACE is a more abstracted idea of place excluding the group of bodies. The idea of NUMBER includes only the particular arrangements, or distributions of a group of bodies, and is therefore only a more abstracted idea of the parts of the figure of the group of bodies; thus when I say England is divided into forty counties, I only speak of certain divisions of its figure. Hence arises the certainty of the mathematical sciences, as they explain these properties of bodies, which are exactly resembled by our ideas of them, whilst we are obliged to collect almost all our other knowledge from experiment; that is, by observing the effects exerted by one body upon another. 3. _Of the Penetrability of Matter._ The impossibility of two bodies existing together in the same space cannot be deduced from our idea of solidity, or of figure. As soon as we perceive the motions of objects that surround us, and learn that we possess a power to move our own bodies, we experience, that those objects, which excite in us the idea of solidity and of figure, oppose this voluntary movement of our own organs; as whilst I endeavour to compress between my hands an ivory ball into a spheroid. And we are hence taught by experience, that our own body and those, which we touch, cannot exist in the same part of space. But this by no means demonstrates, that no two bodies can exist together in the same part of space. Galilæo in the preface to his works seems to be of opinion, that matter is not impenetrable; Mr. Michel, and Mr. Boscowich in his Theoria. Philos. Natur. have espoused this hypothesis: which has been lately published by Dr. Priestley, to whom the world is much indebted for so many important discoveries in science. (Hist. of Light and Colours, p. 391.) The uninterrupted passage of light through transparent bodies, of the electric æther through metallic and aqueous bodies, and of the magnetic effluvia through all bodies, would seem to give some probability to this opinion. Hence it appears, that beings may exist without possessing the property of solidity, as well as they can exist without possessing the properties, which excite our smell or taste, and can thence occupy space without detruding other bodies from it; but we cannot become acquainted with such beings by our sense of touch, any more than we can with odours or flavours without our senses of smell and taste. But that any being can exist without existing in space, is to my ideas utterly incomprehensible. My appeal is to common sense. _To be_ implies a when and a where; the one is comparing it with the motions of other beings, and the other with their situations. If there was but one object, as the whole creation may be considered as one object, then I cannot ask where it exists? for there are no other objects to compare its situation with. Hence if any one denies, that a being exists in space, he denies, that there are any other beings but that one; for to answer the question, "Where does it exist?" is only to mention the situation of the objects that surround it. In the same manner if it be asked--"When does a being exist?" The answer only specifies the successive motions either of itself, or of other bodies; hence to say, a body exists not in time, is to say, that there is, or was, no motion in the world. 4. _Of the Spirit of Animation._ But though there may exist beings in the universe, that have not the property of solidity; that is, which can possess any part of space, at the same time that it is occupied by other bodies; yet there may be other beings, that can assume this property of solidity, or disrobe themselves of it occasionally, as we are taught of spirits, and of angels; and it would seem, that THE SPIRIT OF ANIMATION must be endued with this property, otherwise how could it occasionally give motion to the limbs of animals?--or be itself stimulated into motion by the obtrusions of surrounding bodies, as of light, or odour? If the spirit of animation was always necessarily penetrable, it could not influence or be influenced by the solidity of common matter; they would exist together, but could not detrude each other from the part of space, where they exist; that is, they could not communicate motion to each other. _No two things can influence or affect each other, which have not some property common to both of them_; for to influence or affect another body is to give or communicate some property to it, that it had not before; but how can one body give that to another, which it does not possess itself?--The words imply, that they must agree in having the power or faculty of possessing some common property. Thus if one body removes another from the part of space, that it possesses, it must have the power of occupying that space itself: and if one body communicates heat or motion to another, it follows, that they have alike the property of possessing heat or motion. Hence the spirit of animation at the time it communicates or receives motion from solid bodies, must itself possess some property of solidity. And in consequence at the time it receives other kinds of motion from light, it must possess that property, which light possesses, to communicate that kind of motion; and for which no language has a name, unless it may be termed Visibility. And at the time it is stimulated into other kinds of animal motion by the particles of sapid and odorous bodies affecting the senses of taste and smell, it must resemble these particles of flavour, and of odour, in possessing some similar or correspondent property; and for which language has no name, unless we may use the words Saporosity and Odorosity for those common properties, which are possessed by our organs of taste and smell, and by the particles of sapid and odorous bodies; as the words Tangibility and Audibility may express the common property possessed by our organs of touch, and of hearing, and by the solid bodies, or their vibrations, which affect those organs. 5. Finally, though the figures of bodies are in truth resembled by the figure of the part of the organ of touch, which is stimulated into motion; and that organ resembles the solid body, which stimulates it, in its property of solidity; and though the sense of hearing resembles the vibrations of external bodies in its capability of being stimulated into motion by those vibrations; and though our other organs of sense resemble the bodies, that stimulate them, in their capability of being stimulated by them; and we hence become acquainted with these properties of the external world; yet as we can repeat all these motions of our organs of sense by the efforts of volition, or in consequence of the sensation of pleasure or pain, or by their association with other fibrous motions, as happens in our reveries or in sleep, there would still appear to be some difficulty in demonstrating the existence of any thing external to us. In our dreams we cannot determine this circumstance, because our power of volition is suspended, and the stimuli of external objects are excluded; but in our waking hours we can compare our ideas belonging to one sense with those belonging to another, and can thus distinguish the ideas occasioned by irritation from those excited by sensation, volition, or association. Thus if the idea of the sweetness of sugar should be excited in our dreams, the whiteness and hardness of it occur at the same time by association; and we believe a material lump of sugar present before us. But if, in our waking hours, the idea of the sweetness of sugar occurs to us, the stimuli of surrounding objects, as the edge of the table, on which we press, or green colour of the grass, on which we tread, prevent the other ideas of the hardness and whiteness of the sugar from being exerted by association. Or if they should occur, we voluntarily compare them with the irritative ideas of the table or grass above mentioned, and detect their fallacy. We can thus distinguish the ideas caused by the stimuli of external objects from those, which are introduced by association, sensation, or volition; and during our waking hours can thus acquire a knowledge of the external world. Which nevertheless we cannot do in our dreams, because we have neither perceptions of external bodies, nor the power of volition to enable us to compare them with the ideas of imagination. III. _Of Vision._ Our eyes observe a difference of colour, or of shade, in the prominences and depressions of objects, and that those shades uniformly vary, when the sense of touch observes any variation. Hence when the retina becomes stimulated by colours or shades of light in a certain form, as in a circular spot; we know by experience, that this is a sign, that a tangible body is before us; and that its figure is resembled by the miniature figure of the part of the organ of vision, that is thus stimulated. Here whilst the stimulated part of the retina resembles exactly the visible figure of the whole in miniature, the various kinds of stimuli from different colours mark the visible figures of the minuter parts; and by habit we instantly recall the tangible figures. Thus when a tree is the object of sight, a part of the retina resembling a flat branching figure is stimulated by various shades of colours; but it is by suggestion, that the gibbosity of the tree, and the moss, that fringes its trunk, appear before us. These are ideas of suggestion, which we feel or attend to, associated with the motions of the retina, or irritative ideas, which we do not attend to. So that though our visible ideas resemble in miniature the outline of the figure of coloured bodies, in other respects they serve only as a language, which by acquired associations introduce the tangible ideas of bodies. Hence it is, that this sense is so readily deceived by the art of the painter to our amusement and instruction. The reader will find much very curious knowledge on this subject in Bishop Berkley's Essay on Vision, a work of great ingenuity. The immediate object however of the sense of vision is light; this fluid, though its velocity is so great, appears to have no perceptible mechanical impulse, as was mentioned in the third Section, but seems to stimulate the retina into animal motion by its transmission through this part of the sensorium: for though the eyes of cats or other animals appear luminous in obscure places; yet it is probable, that none of the light, which falls on the retina, is reflected from it, but adheres to or enters into combination with the choroide coat behind it. The combination of the particles of light with opake bodies, and therefore with the choroide coat of the eye, is evinced from the heat, which is given out, as in other chemical combinations. For the sunbeams communicate no heat in their passage through transparent bodies, with which they do not combine, as the air continues cool even in the focus of the largest burning-glasses, which in a moment vitrifies a particle of opaque matter. IV. _Of the Organ of Hearing._ It is generally believed, that the tympanum of the ear vibrates mechanically, when exposed to audible sounds, like the strings of one musical instrument, when the same notes are struck upon another. Nor is this opinion improbable, as the muscles and cartilages of the larynx are employed in producing variety of tones by mechanical vibration: so the muscles and bones of the ear seem adapted to increase or diminish the tension of the tympanum for the purposes of similar mechanical vibrations. But it appears from dissection, that the tympanum is not the immediate organ of hearing, but that like the humours and cornea of the eye, it is only of use to prepare the object for the immediate organ. For the portio mollis of the auditory nerve is not spread upon the tympanum, but upon the vestibulum, and cochlea, and semicircular canals of the ear; while between the tympanum and the expansion of the auditory nerve the cavity is said by Dr. Cotunnus and Dr. Meckel to be filled with water; as they had frequently observed by freezing the heads of dead animals before they dissected them; and water being a more dense fluid than air is much better adapted to the propagation of vibrations. We may add, that even the external opening of the ear is not absolutely necessary for the perception of sound: for some people, who from these defects would have been completely deaf, have distinguished acute or grave sounds by the tremours of a stick held between their teeth propagated along the bones of the head, (Haller. Phys. T. V. p. 295). Hence it appears, that the immediate organ of hearing is not affected by the particles of the air themselves, but is stimulated into animal motion by the vibrations of them. And it is probable from the loose bones, which are found in the heads of some fishes, that the vibrations of water are sensible to the inhabitants of that element by a similar organ. The motions of the atmosphere, which we become acquainted with by the sense of touch, are combined with its solidity, weight, or vis intertiæ; whereas those, that are perceived by this organ, depend alone on its elasticity. But though the vibration of the air is the immediate object of the sense of hearing, yet the ideas, we receive by this sense, like those received from light, are only as a language, which by acquired associations acquaints us with those motions of tangible bodies, which depend on their elasticity; and which we had before learned by our sense of touch. V. _Of Smell and of Taste._ The objects of smell are dissolved in the fluid atmosphere, and those of taste in the saliva, or other aqueous fluid, for the better diffusing them on their respective organs, which seem to be stimulated into animal motion perhaps by the chemical affinities of these particles, which constitute the sapidity and odorosity of bodies with the nerves of sense, which perceive them. Mr. Volta has lately observed a curious circumstance relative to our sense of taste. If a bit of clean lead and a bit of clean silver be separately applied to the tongue and palate no taste is perceived; but by applying them in contact in respect to the parts out of the mouth, and nearly so in respect to the parts, which are immediately applied to the tongue and palate, a saline or acidulous taste is perceived, as of a fluid like a stream of electricity passing from one of them to the other. This new application of the sense of taste deserves further investigation, as it may acquaint us with new properties of matter. From the experiments above mentioned of Galvani, Volta, Fowler, and others, it appears, that a plate of zinc and a plate of silver have greater effect than lead and silver. If one edge of a plate of silver about the size of half a crown-piece be placed upon the tongue, and one edge of a plate of zinc about the same size beneath the tongue, and if their opposite edges are then brought into contact before the point of the tongue, a taste is perceived at the moment of their coming into contact; secondly, if one of the above plates be put between the upper lip and the gum of the fore-teeth, and the other be placed under the tongue, and their exterior edges be then brought into contact in a darkish room, a flash of light is perceived in the eyes. These effects I imagine only shew the sensibility of our nerves of sense to very small quantities of the electric fluid, as it passes through them; for I suppose these sensations are occasioned by slight electric shocks produced in the following manner. By the experiments published by Mr. Bennet, with his ingenious doubler of electricity, which is the greatest discovery made in that science since the coated jar, and the eduction of lightning from the skies, it appears that zinc was always found minus, and silver was always found plus, when both of them were in their separate state. Hence, when they are placed in the manner above described, as soon as their exterior edges come nearly into contact, so near as to have an extremely thin plate of air between them, that plate of air becomes charged in the same manner as a plate of coated glass; and is at the same instant discharged through the nerves of taste or of sight, and gives the sensations, as above described, of light or of saporocity; and only shews the great sensibility of these organs of sense to the stimulus of the electric fluid in suddenly passing through them. VI. _Of the Sense of Heat._ There are many experiments in chemical writers, that evince the existence of heat as a fluid element, which covers and pervades all bodies, and is attracted by the solutions of some of them, and is detruded from the combination of others. Thus from the combinations of metals with acids, and from those combinations of animal fluids, which are termed secretions, this fluid matter of heat is given out amongst the neighbouring bodies; and in the solutions of salts in water, or of water in air, it is absorbed from the bodies, that surround them; whilst in its facility in passing through metallic bodies, and its difficulty in pervading resins and glass, it resembles the properties of the electric aura; and is like that excited by friction, and seems like that to gravitate amongst other bodies in its uncombined state, and to find its equilibrium. There is no circumstance of more consequence in the animal economy than a due proportion of this fluid of heat; for the digestion of our nutriment in the stomach and bowels, and the proper qualities of all our secreted fluids, as they are produced or prepared partly by animal and partly by chemical processes, depend much on the quantity of heat; the excess of which, or its deficiency, alike gives us pain, and induces us to avoid the circumstances that occasion them. And in this the perception of heat essentially differs from the perceptions of the sense of touch, as we receive pain from too great pressure of solid bodies, but none from the absence of it. It is hence probable, that nature has provided us with a set of nerves for the perception of this fluid, which anatomists have not yet attended to. There may be some difficulty in the proof of this assertion; if we look at a hot fire, we experience no pain of the optic nerve, though the heat along with the light must be concentrated upon it. Nor does warm water or warm oil poured into the ear give pain to the organ of hearing; and hence as these organs of sense do not perceive small excesses or deficiences of heat; and as heat has no greater analogy to the solidity or to the figures of bodies, than it has to their colours or vibrations; there seems no sufficient reason for our ascribing the perception of heat and cold to the sense of touch; to which it has generally been attributed, either because it is diffused beneath the whole skin like the sense of touch, or owing to the inaccuracy of our observations, or the defect of our languages. There is another circumstance would induce us to believe, that the perceptions of heat and cold do not belong to the organ of touch; since the teeth, which are the least adapted for the perceptions of solidity or figure, are the most sensible to heat or cold; whence we are forewarned from swallowing those materials, whose degree of coldness or of heat would injure our stomachs. The following is an extract from a letter of Dr. R.W. Darwin, of Shrewsbury, when he was a student at Edinburgh. "I made an experiment yesterday in our hospital, which much favours your opinion, that the sensation of heat and of touch depend on different sets of nerves. A man who had lately recovered from a fever, and was still weak, was seized with violent cramps in his legs and feet; which were removed by opiates, except that one of his feet remained insensible. Mr. Ewart pricked him with a pin in five or six places, and the patient declared he did not feel it in the least, nor was he sensible of a very smart pinch. I then held a red-hot poker at some distance, and brought it gradually nearer till it came within three inches, when he asserted that he felt it quite distinctly. I suppose some violent irritation on the nerves of touch had caused the cramps, and had left them paralytic; while the nerves of heat, having suffered no increased stimulus, retained their irritability." Add to this, that the lungs, though easily stimulated into inflammation, are not sensible to heat. See Class. III. 1. 1. 10. VII. _Of the Sense of Extension._ The organ of touch is properly the sense of pressure, but the muscular fibres themselves constitute the organ of sense, that feels extension. The sense of pressure is always attended with the ideas of the figure and solidity of the object, neither of which accompany our perception of extension. The whole set of muscles, whether they are hollow ones, as the heart, arteries, and intestines, or longitudinal ones attached to bones, contract themselves, whenever they are stimulated by forcible elongation; and it is observable, that the white muscles, which constitute the arterial system, seem to be excited into contraction from no other kinds of stimulus, according to the experiments of Haller. And hence the violent pain in some inflammations, as in the paronychia, obtains immediate relief by cutting the membrane, that was stretched by the tumour of the subjacent parts. Hence the whole muscular system may be considered as one organ of sense, and the various attitudes of the body, as ideas belonging to this organ, of many of which we are hourly conscious, while many others, like the irritative ideas of the other senses, are performed without our attention. When the muscles of the heart cease to act, the refluent blood again distends or elongates them; and thus irritated they contract as before. The same happens to the arterial system, and I suppose to the capillaries, intestines, and various glands of the body. When the quantity of urine, or of excrement, distends the bladder, or rectum, those parts contract, and exclude their contents, and many other muscles by association act along with them; but if these evacuations are not soon complied with, pain is produced by a little further extension of the muscular fibres: a similar pain is caused in the muscles, when a limb is much extended for the reduction of dislocated bones; and in the punishment of the rack: and in the painful cramps of the calf of the leg, or of other muscles, for a greater degree of contraction of a muscle, than the movement of the two bones, to which its ends are affixed, will admit of, must give similar pain to that, which is produced by extending it beyond its due length. And the pain from punctures or incisions arises from the distention of the fibres, as the knife passes through them; for it nearly ceases as soon as the division is completed. All these motions of the muscles, that are thus naturally excited by the stimulus of distending bodies, are also liable to be called into strong action by their catenation, with the irritations or sensations produced by the momentum of the progressive particles of blood in the arteries, as in inflammatory fevers, or by acrid substances on other sensible organs, as in the strangury, or tenesmus, or cholera. We shall conclude this account of the sense of extension by observing, that the want of its object is attended with a disagreeable sensation, as well as the excess of it. In those hollow muscles, which have been accustomed to it, this disagreeable sensation is called faintness, emptiness, and sinking; and, when it arises to a certain degree, is attended with syncope, or a total quiescence of all motions, but the internal irritative ones, as happens from sudden loss of blood, or in the operation of tapping in the dropsy. VIII. _Of the Appetites of Hunger, Thirst, Heat, Extension, the want of fresh Air, animal Love, and the Suckling of Children._ Hunger is most probably perceived by those numerous ramifications of nerves that are seen about the upper opening of the stomach; and thirst by the nerves about the fauces, and the top of the gula. The ideas of these senses are few in the generality of mankind, but are more numerous in those, who by disease, or indulgence, desire particular kinds of foods or liquids. A sense of heat has already been spoken of, which may with propriety be called an appetite, as we painfully desire it, when it is deficient in quantity. The sense of extension may be ranked amongst these appetites, since the deficiency of its object gives disagreeable sensation; when this happens in the arterial system, it is called faintness, and seems to bear some analogy to hunger and to cold; which like it are attended with emptiness of a part of the vascular system. The sense of want of fresh air has not been attended to, but is as distinct as the others, and the first perhaps that we experience after our nativity; from the want of the object of this sense many diseases are produced, as the jail-fever, plague, and other epidemic maladies. Animal love is another appetite, which occurs later in life, and the females of lactiferous animals have another natural inlet of pleasure or pain from the suckling their offspring. The want of which either owing to the death of their progeny, or to the fashion of their country, has been fatal to many of the sex. The males have also pectoral glands, which are frequently turgid with a thin milk at their nativity, and are furnished with nipples, which erect on titillation like those of the female; but which seem now to be of no further use, owing perhaps to some change which these animals have undergone in the gradual progression of the formation of the earth, and of all that it inhabit. These seven last mentioned senses may properly be termed appetites, as they differ from those of touch, sight, hearing, taste, and smell, in this respect; that they are affected with pain as well by the defect of their objects as by the excess of them, which is not so in the latter. Thus cold and hunger give us pain, as well as an excess of heat or satiety; but it is not so with darkness and silence. IX. Before we conclude this Section on the organs of sense, we must observe, that, as far as we know, there are many more senses, than have been here mentioned, as every gland seems to be influenced to separate from the blood, or to absorb from the cavities of the body, or from the atmosphere, its appropriated fluid, by the stimulus of that fluid on the living gland; and not by mechanical capillary absorption, nor by chemical affinity. Hence it appears, that each of these glands must have a peculiar organ to perceive these irritations, but as these irritations are not succeeded by sensation, they have not acquired the names of senses. However when these glands are excited into motions stronger than usual, either by the acrimony of their fluids, or by their own irritability being much increased, then the sensation of pain is produced in them as in all the other senses of the body; and these pains are all of different kinds, and hence the glands at this time really become each a different organ of sense, though these different kinds of pain have acquired no names. Thus a great excess of light does not give the idea of light but of pain; as in forcibly opening the eye when it is much inflamed. The great excess of pressure or distention, as when the point of a pin is pressed upon our skin, produces pain, (and when this pain of the sense of distention is slighter, it is termed itching, or tickling), without any idea of solidity or of figure: an excess of heat produces smarting, of cold another kind of pain; it is probable by this sense of heat the pain produced by caustic bodies is perceived, and of electricity, as all these are fluids, that permeate, distend, or decompose the parts that feel them. * * * * * SECT. XV. OF THE CLASSES OF IDEAS. I. 1. _Ideas received in tribes._ 2. _We combine them further, or abstract from these tribes._ 3. _Complex ideas._ 4. _Compounded ideas._ 5. _Simple ideas, modes, substances, relations, general ideas._ 6. _Ideas of reflexion._ 7. _Memory and imagination imperfectly defined. Ideal presence. Memorandum-rings._ II. 1. _Irritative ideas. Perception._ 2. _Sensitive ideas, imagination._ 3. _Voluntary ideas, recollection._ 4. _Associated ideas, suggestion._ III. 1. _Definitions of perception, memory._ 2. _Reasoning, judgment, doubting, distinguishing, comparing._ 3. _Invention._ 4. _Consciousness._ 5. _Identity._ 6. _Lapse of time._ 7. _Free-will._ I. 1. As the constituent elements of the material world are only perceptible to our organs of sense in a state of combination; it follows, that the ideas or sensual motions excited by them, are never received singly, but ever with a greater or less degree of combination. So the colours of bodies or their hardnesses occur with their figures: every smell and taste has its degree of pungency as well as its peculiar flavour: and each note in music is combined with the tone of some instrument. It appears from hence, that we can be sensible of a number of ideas at the same time, such as the whiteness, hardness, and coldness, of a snow-ball, and can experience at the same time many irritative ideas of surrounding bodies, which we do not attend to, as mentioned in Section VII. 3. 2. But those ideas which belong to the same sense, seem to be more easily combined into synchronous tribes, than those which were not received by the same sense, as we can more easily think of the whiteness and figure of a lump of sugar at the same time, than the whiteness and sweetness of it. 2. As these ideas, or sensual motions, are thus excited with greater or less degrees of combination; so we have a power, when we repeat them either by our volition or sensation, to increase or diminish this degree of combination, that is, to form compounded ideas from those, which were more simple; and abstract ones from those, which were more complex, when they were first excited; that is, we can repeat a part or the whole of those sensual motions, which did constitute our ideas of perception; and the repetition of which now constitutes our ideas of recollection, or of imagination. 3. Those ideas, which we repeat without change of the quantity of that combination, with which we first received them, are called complex ideas, as when you recollect Westminster Abbey, or the planet Saturn: but it must be observed, that these complex ideas, thus re-excited by volition, sensation, or association, are seldom perfect copies of their correspondent perceptions, except in our dreams, where other external objects do not detract our attention. 4. Those ideas, which are more complex than the natural objects that first excited them, have been called compounded ideas, as when we think of a sphinx, or griffin. 5. And those that are less complex than the correspondent natural objects, have been termed abstracted ideas: thus sweetness, and whiteness, and solidity, are received at the same time from a lump of sugar, yet I can recollect any of these qualities without thinking of the others, that were excited along with them. When ideas are so far abstracted as in the above example, they have been termed simple by the writers of metaphysics, and seem indeed to be more complete repetitions of the ideas or sensual motions, originally excited by external objects. Other classes of these ideas, where the abstraction has not been so great, have been termed, by Mr. Locke, modes, substances, and relations, but they seem only to differ in their degree of abstraction from the complex ideas that were at first excited; for as these complex or natural ideas are themselves imperfect copies of their correspondent perceptions, so these abstract or general ideas are only still more imperfect copies of the same perceptions. Thus when I have seen an object but once, as a rhinoceros, my abstract idea of this animal is the same as my complex one. I may think more or less distinctly of a rhinoceros, but it is the very rhinoceros that I saw, or some part or property of him, which recurs to my mind. But when any class of complex objects becomes the subject of conversation, of which I have seen many individuals, as a castle or an army, some property or circumstance belonging to it is peculiarly alluded to; and then I feel in my own mind, that my abstract idea of this complex object is only an idea of that part, property, or attitude of it, that employs the present conversation, and varies with every sentence that is spoken concerning it. So if any one should say, "one may sit upon a horse safer than on a camel," my abstract idea of the two animals includes only an outline of the level back of the one, and the gibbosity on the back of the other. What noise is that in the street?--Some horses trotting over the pavement. Here my idea of the horses includes principally the shape and motion of their legs. So also the abstract ideas of goodness and courage are still more imperfect representations of the objects they were received from; for here we abstract the material parts, and recollect only the qualities. Thus we abstract so much from some of our complex ideas, that at length it becomes difficult to determine of what perception they partake; and in many instances our idea seems to be no other than of the sound or letters of the word, that stands for the collective tribe, of which we are said to have an abstracted idea, as noun, verb, chimæra, apparition. 6. Ideas have been divided into those of perception and those of reflection, but as whatever is perceived must be external to the organ that perceives it, all our ideas must originally be ideas of perception. 7. Others have divided our ideas into those of memory, and those of imagination; they have said that a recollection of ideas in the order they were received constitutes memory, and without that order imagination; but all the ideas of imagination, excepting the few that are termed simple ideas, are parts of trains or tribes in the order they were received; as if I think of a sphinx, or a griffin, the fair face, bosom, wings, claws, tail, are all complex ideas in the order they were received: and it behoves the writers, who adhere to this definition, to determine, how small the trains must be, that shall be called imagination; and how great those, that shall be called memory. Others have thought that the ideas of memory have a greater vivacity than those of imagination: but the ideas of a person in sleep, or in a waking reverie, where the trains connected with sensation are uninterrupted, are more vivid and distinct than those of memory, so that they cannot be distinguished by this criterion. The very ingenious author of the Elements of Criticism has described what he conceives to be a species of memory, and calls it ideal presence; but the instances he produces are the reveries of sensation, and are therefore in truth connections of the imagination, though they are recalled in the order they were received. The ideas connected by association are in common discourse attributed to memory, as we talk of memorandum-rings, and tie a knot on our handkerchiefs to bring something into our minds at a distance of time. And a school-boy, who can repeat a thousand unmeaning lines in Lilly's Grammar, is said to have a good memory. But these have been already shewn to belong to the class of association; and are termed ideas of suggestion. II. Lastly, the method already explained of classing ideas into those excited by irritation, sensation, volition, or association, we hope will be found more convenient both for explaining the operations of the mind, and for comparing them with those of the body; and for the illustration and the cure of the diseases of both, and which we shall here recapitulate. 1. Irritative ideas are those, which are preceded by irritation, which is excited by objects external to the organs of sense: as the idea of that tree, which either I attend to, or which I shun in walking near it without attention. In the former case it is termed perception, in the latter it is termed simply an irritative idea. 2. Sensitive ideas are those, which are preceded by the sensation of pleasure or pain; as the ideas, which constitute our dreams or reveries, this is called imagination. 3. Voluntary ideas are those, which are preceded by voluntary exertion, as when I repeat the alphabet backwards: this is called recollection. 4. Associate ideas are those, which are preceded by other ideas or muscular motions, as when we think over or repeat the alphabet by rote in its usual order; or sing a tune we are accustomed to; this is called suggestion. III. 1. Perceptions signify those ideas, which are preceded by irritation and succeeded by the sensation of pleasure or pain, for whatever excites our attention interests us; that is, it is accompanied with, pleasure or pain; however slight may be the degree or quantity of either of them. The word memory includes two classes of ideas, either those which, are preceded by voluntary exertion, or those which are suggested by their associations with other ideas. 2. Reasoning is that operation of the sensorium, by which we excite two or many tribes of ideas; and then re-excite the ideas, in which they differ, or correspond. If we determine this difference, it is called judgment; if we in vain endeavour to determine it, it is called doubting. If we re-excited the ideas, in which they differ, it is called distinguishing. If we re-excite those in which they correspond, it is called comparing. 3. Invention is an operation of the sensorium, by which we voluntarily continue to excite one train of ideas, suppose the design of raising water by a machine; and at the same time attend to all other ideas, which are connected with this by every kind of catenation; and combine or separate them voluntarily for the purpose of obtaining some end. For we can create nothing new, we can only combine or separate the ideas, which we have already received by our perceptions: thus if I wish to represent a monster, I call to my mind the ideas of every thing disagreeable and horrible, and combine the nastiness and gluttony of a hog, the stupidity and obstinacy of an ass, with the fur and awkwardness of a bear, and call the new combination Caliban. Yet such a monster may exist in nature, as all his attributes are parts of nature. So when I wish to represent every thing, that is excellent, and amiable; when I combine benevolence with cheerfulness, wisdom, knowledge, taste, wit, beauty of person, and elegance of manners, and associate them in one lady as a pattern to the world, it is called invention; yet such a person may exist,--such a person does exist!--It is ---- ----, who is as much a monster as Caliban. 4. In respect to consciousness, we are only conscious of our existence, when we think about it; as we only perceive the lapse of time, when we attend to it; when we are busied about other objects, neither the lapse of time nor the consciousness of our own existence can occupy our attention. Hence, when we think of our own existence, we only excite abstracted or reflex ideas (as they are termed), of our principal pleasures or pains, of our desires or aversions, or of the figure, solidity, colour, or other properties of our bodies, and call that act of the sensorium a consciousness of our existence. Some philosopher, I believe it is Des Cartes, has said, "I think, therefore I exist." But this is not right reasoning, because thinking is a mode of existence; and it is thence only saying, "I exist, therefore I exist." For there are three modes of existence, or in the language of grammarians three kinds of verbs. First, simply I am, or exist. Secondly, I am acting, or exist in a state of activity, as I move. Thirdly, I am suffering, or exist in a state of being acted upon, as I am moved. The when, and the where, as applicable to this existence, depends on the successive motions of our own or of other bodies; and on their respective situations, as spoken of Sect. XIV. 2. 5. 5. Our identity is known by our acquired habits or catenated trains of ideas and muscular motions; and perhaps, when we compare infancy with old age, in those alone can our identity be supposed to exist. For what else is there of similitude between the first speck of living entity and the mature man?--every deduction of reasoning, every sentiment or passion, with every fibre of the corporeal part of our system, has been subject almost to annual mutation; while some catenations alone of our ideas and muscular actions have continued in part unchanged. By the facility, with which we can in our waking hours voluntarily produce certain successive trains of ideas, we know by experience, that we have before reproduced them; that is, we are conscious of a time of our existence previous to the present time; that is, of our identity now and heretofore. It is these habits of action, these catenations of ideas and muscular motions, which begin with life, and only terminate with it; and which we can in some measure deliver to our posterity; as explained in Sect. XXXIX. 6. When the progressive motions of external bodies make a part of our present catenation of ideas, we attend to the lapse of time; which appears the longer, the more frequently we thus attend to it; as when we expect something at a certain hour, which much interests us, whether it be an agreeable or disagreeable event; or when we count the passing seconds on a stop-watch. When an idea of our own person, or a reflex idea of our pleasures and pains, desires and aversions, makes a part of this catenation, it is termed consciousness; and if this idea of consciousness makes a part of a catenation, which we excite by recollection, and know by the facility with which we excite it, that we have before experienced it, it is called identity, as explained above. 7. In respect to freewill, it is certain, that we cannot will to think of a new train of ideas, without previously thinking of the first link of it; as I cannot will to think of a black swan, without previously thinking of a black swan. But if I now think of a tail, I can voluntarily recollect all animals, which have tails; my will is so far free, that I can pursue the ideas linked to this idea of tail, as far as my knowledge of the subject extends; but to will without motive is to will without desire or aversion; which is as absurd as to feel without pleasure or pain; they are both solecisms in the terms. So far are we governed by the catenations of motions, which affect both the body and the mind of man, and which begin with our irritability, and end with it. * * * * * SECT. XVI. OF INSTINCT. Haud equidem credo, quia sit divinitus illis Ingenium, aut rerum fato prudentia major.--Virg. Georg. L. I. 415. I. _Instinctive actions defined. Of connate passions._ II. _Of the sensations and motions of the foetus in the womb._ III. _Some animals are more perfectly formed than others before nativity. Of learning to walk._ IV. _Of the swallowing, breathing, sucking, pecking, and lapping of young animals._ V. _Of the sense of smell, and its uses to animals. Why cats do not eat their kittens._ VI. _Of the accuracy of sight in mankind, and their sense of beauty. Of the sense of touch in elephants, monkies, beavers, men._ VII. _Of natural language._ VIII. _The origin of natural language;_ 1. _the language of fear;_ 2. _of grief;_ 3. _of tender pleasure;_ 4. _of serene pleasure;_ 5. _of anger;_ 6. _of attention._ IX. _Artificial language of turkies, hens, ducklings, wagtails, cuckoos, rabbits, dogs, and nightingales._ X. _Of music; of tooth-edge; of a good ear; of architecture._ XI. _Of acquired knowledge; of foxes, rooks, fieldfares, lapwings, dogs, cats, horses, crows, and pelicans._ XII. _Of birds of passage, dormice, snakes, bats, swallows, quails, ringdoves, stare, chaffinch, hoopoe, chatterer, hawfinch, crossbill, rails and cranes._ XIII. _Of birds nests; of the cuckoo; of swallows nests; of the taylor bird._ XIV. _Of the old soldier; of haddocks, cods, and dog fish; of the remora; of crabs, herrings, and salmon._ XV. _Of spiders, caterpillars, ants, and the ichneumon._ XVI. 1. _Of locusts, gnats;_ 2. _bees;_ 3. _dormice, flies, worms, ants, and wasps._ XVII. _Of the faculty that distinguishes man from the brutes._ I. All those internal motions of animal bodies, which contribute to digest their aliment, produce their secretions, repair their injuries, or increase their growth, are performed without our attention or consciousness. They exist as well in our sleep, as in our waking hours, as well in the foetus during the time of gestation, as in the infant after nativity, and proceed with equal regularity in the vegetable as in the animal system. These motions have been shewn in a former part of this work to depend on the irritations of peculiar fluids, and as they have never been classed amongst the instinctive actions of animals, are precluded from our present disquisition. But all those actions of men or animals, that are attended with consciousness, and seem neither to have been directed by their appetites, taught by their experience, nor deduced from observation or tradition, have been referred to the power of instinct. And this power has been explained to be a _divine something_, a kind of inspiration; whilst the poor animal, that possesses it, has been thought little better than _a machine_! The _irksomeness_, that attends a continued attitude of the body, or the _pains_, that we receive from heat, cold, hunger, or other injurious circumstances, excite us to _general locomotion_: and our senses are so formed and constituted by the hand of nature, that certain objects present us with pleasure, others with pain, and we are induced to approach and embrace these, to avoid and abhor those, as such sensations direct us. Thus the palates of some animals are gratefully affected by the mastication of fruits, others of grains, and others of flesh; and they are thence instigated to attain, and to consume those materials; and are furnished with powers of muscular motion, and of digestion proper for such purposes. These _sensations_ and _desires_ constitute a part of our system, as our _muscles_ and _bones_ constitute another part: and hence they may alike be termed _natural_ or _connate_; but neither of them can properly be termed _instinctive_: as the word instinct in its usual acceptation refers only to the _actions_ of animals, as above explained: the origin of these _actions_ is the subject of our present enquiry. The reader is intreated carefully to attend to this definition of _instinctive actions_, lest by using the word instinct without adjoining any accurate idea to it, he may not only include the natural desires of love and hunger, and the natural sensations of pain or pleasure, but the figure and contexture of the body, and the faculty of reason itself under this general term. II. We experience some sensations, and perform some actions before our nativity; the sensations of cold and warmth, agitation and rest, fulness and inanition, are instances of the former; and the repeated struggles of the limbs of the foetus, which begin about the middle of gestation, and those motions by which it frequently wraps the umbilical chord around its neck or body, and even sometimes ties it on a knot; are instances of the latter. Smellie's Midwifery, (Vol. I. p. 182.) By a due attention to these circumstances many of the actions of young animals, which at first sight seemed only referable to an inexplicable instinct, will appear to have been acquired like all other animal actions, that are attended with consciousness, _by the repeated efforts of our muscles under the conduct of our sensations or desires_. The chick in the shell begins to move its feet and legs on the sixth day of incubation (Mattreican, p. 138); or on the seventh day, (Langley); afterwards they are seen to move themselves gently in the liquid that surrounds them, and to open and shut their mouths, (Harvei, de Generat. p. 62, and 197. Form de Poulet. ii. p. 129). Puppies before the membranes are broken, that involve them, are seen to move themselves, to put out their tongues, and to open and shut their mouths, (Harvey, Gipson, Riolan, Haller). And calves lick themselves and swallow many of their hairs before their nativity: which however puppies do not, (Swammerden, p. 319. Flemyng Phil. Trans. Ann. 1755. 42). And towards the end of gestation, the foetus of all animals are proved to drink part of the liquid in which they swim, (Haller. Physiol. T. 8. 204). The white of egg is found in the mouth and gizzard of the chick, and is nearly or quite consumed before it is hatched, (Harvie de Generat. 58). And the liquor amnii is found in the mouth and stomach of the human foetus, and of calves; and how else should that excrement be produced in the intestines of all animals, which is voided in great quantity soon after their birth; (Gipson, Med. Essays, Edinb. V. i. 13. Halleri Physiolog. T. 3. p. 318. and T. 8). In the stomach of a calf the quantity of this liquid amounted to about three pints, and the hairs amongst it were of the same colour with those on its skin, (Blasii Anat. Animal, p.m. 122). These facts are attested by many other writers of credit, besides those above mentioned. III. It has been deemed a surprising instance of instinct, that calves and chickens should be able to walk by a few efforts almost immediately after their nativity: whilst the human infant in those countries where he is not incumbered with clothes, as in India, is five or six months, and in our climate almost a twelvemonth, before he can safely stand upon his feet. The struggles of all animals in the womb must resemble their mode of swimming, as by this kind of motion they can best change their attitude in water. But the swimming of the calf and chicken resembles their manner of walking, which they have thus in part acquired before their nativity, and hence accomplish it afterwards with very few efforts, whilst the swimming of the human creature resembles that of the frog, and totally differs from his mode of walking. There is another circumstance to be attended to in this affair, that not only the growth of those peculiar parts of animals, which are first wanted to secure their subsistence, are in general furthest advanced before their nativity: but some animals come into the world more completely formed throughout their whole system than others: and are thence much forwarder in all their habits of motion. Thus the colt, and the lamb, are much more perfect animals than the blind puppy, and the naked rabbit; and the chick of the pheasant, and the partridge, has more perfect plumage, and more perfect eyes, as well as greater aptitude to locomotion, than the callow nestlings of the dove, and of the wren. The parents of the former only find it necessary to shew them their food, and to teach them to take it up; whilst those of the latter are obliged for many days to obtrude it into their gaping mouths. IV. From the facts mentioned in No. 2. of this Section, it is evinced that the foetus learns to swallow before its nativity; for it is seen to open its mouth, and its stomach is found filled with the liquid that surrounds it. It opens its mouth, either instigated by hunger, or by the irksomeness of a continued attitude of the muscles of its face; the liquor amnii, in which it swims, is agreeable to its palate, as it consists of a nourishing material, (Haller Phys. T. 8. p. 204). It is tempted to experience its taste further in the mouth, and by a few efforts learns to swallow, in the same manner as we learn all other animal actions, which are attended with consciousness, _by the repeated efforts of our muscles under the conduct of our sensations or volitions_. The inspiration of air into the lungs is so totally different from that of swallowing a fluid in which we are immersed, that it cannot be acquired before our nativity. But at this time, when the circulation of the blood is no longer continued through the placenta, that suffocating sensation, which we feel about the precordia, when we are in want of fresh air, disagreeably affects the infant: and all the muscles of the body are excited into action to relieve this oppression; those of the breast, ribs, and diaphragm are found to answer this purpose, and thus respiration is discovered, and is continued throughout our lives, as often as the oppression begins to recur. Many infants, both of the human creature, and of quadrupeds, struggle for a minute after they are born before they begin to breathe, (Haller Phys. T. 8. p. 400. ib pt. 2. p. 1). Mr. Buffon thinks the action of the dry air upon the nerves of smell of new-born animals, by producing an endeavour to sneeze, may contribute to induce this first inspiration, and that the rarefaction of the air by the warmth of the lungs contributes to induce expiration, (Hist. Nat. Tom. 4. p. 174). Which latter it may effect by producing a disagreeable sensation by its delay, and a consequent effort to relieve it. Many children sneeze before they respire, but not all, as far as I have observed, or can learn from others. At length, by the direction of its sense of smell, or by the officious care of its mother, the young animal approaches the odoriferous rill of its future nourishment, already experienced to swallow. But in the act of swallowing, it is necessary nearly to close the mouth, whether the creature be immersed in the fluid it is about to drink, or not: hence, when the child first attempts to suck, it does not slightly compress the nipple between its lips, and suck as an adult person would do, by absorbing the milk; but it takes the whole nipple into its mouth for this purpose, compresses it between its gums, and thus repeatedly chewing (as it were) the nipple, presses out the milk, exactly in the same manner as it is drawn from the teats of cows by the hands of the milkmaid. The celebrated Harvey observes, that the foetus in the womb must have sucked in a part of its nourishment, because it knows how to suck the minute it is born, as any one may experience by putting a finger between its lips, and because in a few days it forgets this art of sucking, and cannot without some difficulty again acquire it, (Exercit. de Gener. Anim. 48). The same observation is made by Hippocrates. A little further experience teaches the young animal to suck by absorption, as well as by compression; that is, to open the chest as in the beginning of respiration, and thus to rarefy the air in the mouth, that the pressure of the denser external atmosphere may contribute to force out the milk. The chick yet in the shell has learnt to drink by swallowing a part of the white of the egg for its food; but not having experienced how to take up and swallow solid seeds, or grains, is either taught by the felicitous industry of its mother; or by many repeated attempts is enabled at length to distinguish and to swallow this kind of nutriment. And puppies, though they know how to suck like other animals from their previous experience in swallowing, and in respiration; yet are they long in acquiring the art of lapping with their tongues, which from the flaccidity of their cheeks, and length of their mouths, is afterwards a more convenient way for them to take in water. V. The senses of smell and taste in many other animals greatly excel those of mankind, for in civilized society, as our victuals are generally prepared by others, and are adulterated with salt, spice, oil, and empyreuma, we do not hesitate about eating whatever is set before us, and neglect to cultivate these senses: whereas other animals try every morsel by the smell, before they take it into their mouths, and by the taste before they swallow it: and are led not only each to his proper nourishment by this organ of sense, but it also at a maturer age directs them in the gratification of their appetite of love. Which may be further understood by considering the sympathies of these parts described in Class IV. 2. 1. 7. While the human animal is directed to the object of his love by his sense of beauty, as mentioned in No. VI. of this Section. Thus Virgil. Georg. III. 250. Nonne vides, ut tota tremor pertentat equorum Corpora, si tantum notas odor attulit auras? Nonne canis nidum veneris nasutus odore Quærit, et erranti trahitur sublambere linguâ? Respuit at gustum cupidus, labiisque retractis Elevat os, trepidansque novis impellitur æstris Inserit et vivum felici vomere semen.-- Quam tenui filo cæcos adnectit amores Docta Venus, vitæque monet renovare favillam!--ANON. The following curious experiment is related by Galen. "On dissecting a goat great with young I found a brisk embryon, and having detached it from the matrix, and snatching it away before it saw its dam, I brought it into a certain room, where there were many vessels, some filled with wine, others with oil, some with honey, others with milk, or some other liquor; and in others were grains and fruits; we first observed the young animal get upon its feet, and walk; then it shook itself, and afterwards scratched its side with one of its feet: then we saw it smelling to every one of these things, that were set in the room; and when it had smelt to them all, it drank up the milk." L. 6. de locis. cap. 6. Parturient quadrupeds, as cats, and bitches, and sows, are led by their sense of smell to eat the placenta as other common food; why then do they not devour their whole progeny, as is represented in an antient emblem of TIME? This is said sometimes to happen in the unnatural state in which we confine sows; and indeed nature would seem to have endangered her offspring in this nice circumstance! But at this time the stimulus of the milk in the tumid teats of the mother excites her to look out for, and to desire some unknown circumstance to relieve her. At the same time the smell of the milk attracts the exertions of the young animals towards its source, and thus the delighted mother discovers a new appetite, as mentioned in Sect. XIV. 8. and her little progeny are led to receive and to communicate pleasure by this most beautiful contrivance. VI. But though the human species in some of their sensations are much inferior to other animals, yet the accuracy of the sense of touch, which they possess in so eminent a degree, gives them a great superiority of understanding; as is well observed by the ingenious Mr. Buffon. The extremities of other animals terminate in horns, and hoofs, and claws, very unfit for the sensation of touch; whilst the human hand is finely adapted to encompass its object with this organ of sense. The elephant is indeed endued with a fine sense of feeling at the extremity of his proboscis, and hence has acquired much more accurate ideas of touch and of sight than most other creatures. The two following instances of the sagacity of these animals may entertain the reader, as they were told me by some gentlemen of distinct observation, and undoubted veracity, who had been much conversant with our eastern settlements. First, the elephants that are used to carry the baggage of our armies, are put each under the care of one of the natives of Indostan, and whilst himself and his wife go into the woods to collect leaves and branches of trees for his food, they fix him to the ground by a length of chain, and frequently leave a child yet unable to walk, under his protection: and the intelligent animal not only defends it, but as it creeps about, when it arrives near the extremity of his chain, he wraps his trunk gently round its body, and brings it again into the centre of his circle. Secondly, the traitor elephants are taught to walk on a narrow path between two pit-falls, which are covered with turf, and then to go into the woods, and to seduce the wild elephants to come that way, who fall into these wells, whilst he passes safe between them: and it is universally observed, that those wild elephants that escape the snare, pursue the traitor with the utmost vehemence, and if they can overtake him, which sometimes happens, they always beat him to death. The monkey has a hand well enough adapted for the sense of touch, which contributes to his great facility of imitation; but in taking objects with his hands, as a stick or an apple, he puts his thumb on the same side of them with his fingers, instead of counteracting the pressure of his fingers with it: from this neglect he is much slower in acquiring the figures of objects, as he is less able to determine the distances or diameters of their parts, or to distinguish their vis inertiæ from their hardness. Helvetius adds, that the shortness of his life, his being fugitive before mankind, and his not inhabiting all climates, combine to prevent his improvement. (De l'Esprit. T. 1. p.) There is however at this time an old monkey shewn in Exeter Change, London, who having lost his teeth, when nuts are given him, takes a stone into his hand, and cracks them with it one by one; thus using tools to effect his purpose like mankind. The beaver is another animal that makes much use of his hands, and if we may credit the reports of travellers, is possessed of amazing ingenuity. This however, M. Buffon affirms, is only where they exist in large numbers, and in countries thinly peopled with men; while in France in their solitary state they shew no uncommon ingenuity. Indeed all the quadrupeds, that have collar-bones, (claviculæ) use their fore-limbs in some measure as we use our hands, as the cat, squirrel, tyger, bear and lion; and as they exercise the sense of touch more universally than other animals, so are they more sagacious in watching and surprising their prey. All those birds, that use their claws for hands, as the hawk, parrot, and cuckoo, appear to be more docile and intelligent; though the gregarious tribes of birds have more acquired knowledge. Now as the images, that are painted on the retina of the eye, are no other than signs, which recall to our imaginations the objects we had before examined by the organ of touch, as is fully demonstrated by Dr. Berkley in his treatise on vision; it follows that the human creature has greatly more accurate and distinct sense of vision than that of any other animal. Whence as he advances to maturity he gradually acquires a sense of female beauty, which at this time directs him to the object of his new passion. Sentimental love, as distinguished from the animal passion of that name, with which it is frequently accompanied, consists in the desire or sensation of beholding, embracing, and saluting a beautiful object. The characteristic of beauty therefore is that it is the object of love; and though many other objects are in common language called beautiful, yet they are only called so metaphorically, and ought to be termed agreeable. A Grecian temple may give us the pleasurable idea of sublimity, a Gothic temple may give us the pleasurable idea of variety, and a modern house the pleasurable idea of utility; music and poetry may inspire our love by association of ideas; but none of these, except metaphorically, can be termed beautiful; as we have no wish to embrace or salute them. Our perception of beauty consists in our recognition by the sense of vision of those objects, first, which have before inspired our love by the pleasure, which they have afforded to many of our senses: as to our sense of warmth, of touch, of smell, of taste, hunger and thirst; and, secondly, which bear any analogy of form to such objects. When the babe, soon after it is born into this cold world, is applied to its mother's bosom; its sense of perceiving warmth is first agreeably affected; next its sense of smell is delighted with the odour of her milk; then its taste is gratified by the flavour of it: afterwards the appetites of hunger and of thirst afford pleasure by the possession of their objects, and by the subsequent digestion of the aliment; and, lastly, the sense of touch is delighted by the softness and smoothness of the milky fountain, the source of such variety of happiness. All these various kinds of pleasure at length become associated with the form of the mother's breast; which the infant embraces with its hands, presses with its lips, and watches with its eyes; and thus acquires more accurate ideas of the form of its mother's bosom, than of the odour and flavour or warmth, which it perceives by its other senses. And hence at our maturer years, when any object of vision is presented to us, which by its waving or spiral lines bears any similitude to the form of the female bosom, whether it be found in a landscape with soft gradations of rising and descending surface, or in the forms of some antique vases, or in other works of the pencil or the chissel, we feel a general glow of delight, which seems to influence all our senses; and, if the object be not too large, we experience an attraction to embrace it with our arms, and to salute it with our lips, as we did in our early infancy the bosom of our mother. And thus we find, according to the ingenious idea of Hogarth, that the waving lines of beauty were originally taken from the temple of Venus. This animal attraction is love; which is a sensation, when the object is present; and a desire, when it is absent. Which constitutes the purest source of human felicity, the cordial drop in the otherwise vapid cup of life, and which overpays mankind for the care and labour, which are attached to the pre-eminence of his situation above other animals. It should have been observed, that colour as well as form sometimes enters into our idea of a beautiful object, as a good complexion for instance, because a fine or fair colour is in general a sign of health, and conveys to us an idea of the warmth of the object; and a pale countenance on the contrary gives an idea of its being cold to the touch. It was before remarked, that young animals use their lips to distinguish the forms of things, as well as their fingers, and hence we learn the origin of our inclination to salute beautiful objects with our lips. For a definition of Grace, see Class III. 1. 2. 4. VII. There are two ways by which we become acquainted with the passions of others: first, by having observed the effects of them, as of fear or anger, on our own bodies, we know at sight when others are under the influence of these affections. So when two cocks are preparing to fight, each feels the feathers rise round his own neck, and knows from the same sign the disposition of his adversary: and children long before they can speak, or understand the language of their parents, may be frightened by an angry countenance, or soothed by smiles and blandishments. Secondly, when we put ourselves into the attitude that any passion naturally occasions, we soon in some degree acquire that passion; hence when those that scold indulge themselves in loud oaths, and violent actions of the arms, they increase their anger by the mode of expressing themselves: and on the contrary the counterfeited smile of pleasure in disagreeable company soon brings along with it a portion of the reality, as is well illustrated by Mr. Burke. (Essay on the Sublime and Beautiful.) This latter method of entering into the passions of others is rendered of very extensive use by the pleasure we take in imitation, which is every day presented before our eyes, in the actions of children, and indeed in all the customs and fashions of the world. From this our aptitude to imitation, arises what is generally understood by the word sympathy so well explained by Dr. Smith of Glasgow. Thus the appearance of a cheerful countenance gives us pleasure, and of a melancholy one makes us sorrowful. Yawning and sometimes vomiting are thus propagated by sympathy, and some people of delicate fibres, at the presence of a spectacle of misery, have felt pain in the same parts of their own bodies, that were diseased or mangled in the other. Amongst the writers of antiquity Aristotle thought this aptitude to imitation an essential property of the human species, and calls man an imitative animal. [Greek: To zôon mimômenon]. These then are the natural signs by which we understand each other, and on this slender basis is built all human language. For without some natural signs, no artificial ones could have been invented or understood, as is very ingeniously observed by Dr. Reid. (Inquiry into the Human Mind.) VIII. The origin of this universal language is a subject of the highest curiosity, the knowledge of which has always been thought utterly inaccessible. A part of which we shall however here attempt. Light, sound, and odours, are unknown to the foetus in the womb, which, except the few sensations and motions already mentioned, sleeps away its time insensible of the busy world. But the moment he arrives into day, he begins to experience many vivid pains and pleasures; these are at the same time attended with certain muscular motions, and from this their early, and individual association, they acquire habits of occurring together, that are afterwards indissoluble. 1. _Of Fear._ As soon as the young animal is born, the first important sensations, that occur to him, are occasioned by the oppression about his precordia for want of respiration, and by his sudden transition from ninety-eight degrees of heat into so cold a climate.--He trembles, that is, he exerts alternately all the muscles of his body, to enfranchise himself from the oppression about his bosom, and begins to breathe with frequent and short respirations; at the same time the cold contracts his red skin, gradually turning it pale; the contents of the bladder and of the bowels are evacuated: and from the experience of these first disagreeable sensations the passion of fear is excited, which is no other than the expectation of disagreeable sensations. This early association of motions and sensations persists throughout life; the passion of fear produces a cold and pale skin, with tremblings, quick respiration, and an evacuation of the bladder and bowels, and thus constitutes the natural or universal language of this passion. On observing a Canary bird this morning, January 28, 1772, at the house of Mr. Harvey, near Tutbury, in Derbyshire, I was told it always fainted away, when its cage was cleaned, and desired to see the experiment. The cage being taken from the ceiling, and its bottom drawn out, the bird began to tremble, and turned quite white about the root of his bill: he then opened his mouth as if for breath, and respired quick, stood straighter up on his perch, hung his wings, spread his tail, closed his eyes, and appeared quite stiff and cataleptic for near half an hour, and at length with much trembling and deep respirations came gradually to himself. 2. _Of Grief._ That the internal membrane of the nostrils may be kept always moist, for the better perception of odours, there are two canals, that conduct the tears after they have done their office in moistening and cleaning the ball of the eye into a sack, which is called the lacrymal sack; and from which there is a duct, that opens into the nostrils: the aperture of this duct is formed of exquisite sensibility, and when it is stimulated by odorous particles, or by the dryness or coldness of the air, the sack contracts itself, and pours more of its contained moisture on the organ of smell. By this contrivance the organ is rendered more fit for perceiving such odours, and is preserved from being injured by those that are more strong or corrosive. Many other receptacles of peculiar fluids disgorge their contents, when the ends of their ducts are stimulated; as the gall bladder, when the contents of the duodenum stimulate the extremity of the common bile duct: and the salivary glands, when the termination of their ducts in the mouth are excited by the stimulus of the food we masticate. Atque vesiculæ seminales suum exprimunt fluidum glande penis fricatâ. The coldness and dryness of the atmosphere, compared with the warmth and moisture, which the new-born infant had just before experienced, disagreeably affects the aperture of this lacrymal sack: the tears, that are contained in this sack, are poured into the nostrils, and a further supply is secreted by the lacrymal glands, and diffused upon the eye-balls; as is very visible in the eyes and nostrils of children soon after their nativity. The same happens to us at our maturer age, for in severe frosty weather, snivelling and tears are produced by the coldness and dryness of the air. But the lacrymal glands, which separate the tears from the blood, are situated on the upper external part of the globes of each eye; and, when a greater quantity of tears are wanted, we contract the forehead, and bring down the eye-brows, and use many other distortions of the face, to compress these glands. Now as the suffocating sensation, that produces respiration, is removed almost as soon as perceived, and does not recur again: this disagreeable irritation of the lacrymal ducts, as it must frequently recur, till the tender organ becomes used to variety of odours, is one of the first pains that is repeatedly attended to: and hence throughout our infancy, and in many people throughout their lives, all disagreeable sensations are attended with snivelling at the nose, a profusion of tears, and some peculiar distortions of countenance: according to the laws of early association before mentioned, which constitutes the natural or universal language of grief. You may assure yourself of the truth of this observation, if you will attend to what passes, when you read a distressful tale alone; before the tears overflow your eyes, you will invariably feel a titillation at that extremity of the lacrymal duct, which terminates in the nostril, then the compression of the eyes succeeds, and the profusion of tears. Linnæus asserts, that the female bear sheds tears in grief; the same has been said of the hind, and some other animals. 3. _Of Tender Pleasure._ The first most lively impression of pleasure, that the infant enjoys after its nativity, is excited by the odour of its mother's milk. The organ of smell is irritated by this perfume, and the lacrymal sack empties itself into the nostrils, as before explained, and an increase of tears is poured into the eyes. Any one may observe this, when very young infants are about to suck; for at those early periods of life, the sensation affects the organ of smell, much more powerfully, than after the repeated habits of smelling has inured it to odours of common strength: and in our adult years, the stronger smells, though they are at the same time agreeable to us, as of volatile spirits, continue to produce an increased secretion of tears. This pleasing sensation of smell is followed by the early affection of the infant to the mother that suckles it, and hence the tender feelings of gratitude and love, as well as of hopeless grief, are ever after joined with the titillation of the extremity of the lacrymal ducts, and a profusion of tears. Nor is it singular, that the lacrymal sack should be influenced by pleasing ideas, as the sight of agreeable food produces the same effect on the salivary glands. Ac dum vidimus insomniis lascivæ puellæ simulacrum tenditur penis. Lambs shake or wriggle their tails, at the time when they first suck, to get free of the hard excrement, which had been long lodged in their bowels. Hence this becomes afterwards a mark of pleasure in them, and in dogs, and other tailed animals. But cats gently extend and contract their paws when they are pleased, and purr by drawing in their breath, both which resemble their manner of sucking, and thus become their language of pleasure, for these animals having collar-bones use their paws like hands when they suck, which dogs and sheep do not. 4. _Of Serene Pleasure._ In the action of sucking, the lips of the infant are closed around the nipple of its mother, till he has filled his stomach, and the pleasure occasioned by the stimulus of this grateful food succeeds. Then the sphincter of the mouth, fatigued by the continued action of sucking, is relaxed; and the antagonist muscles of the face gently acting, produce the smile of pleasure: as cannot but be seen by all who are conversant with children. Hence this smile during our lives is associated with gentle pleasure; it is visible in kittens, and puppies, when they are played with, and tickled; but more particularly marks the human features. For in children this expression of pleasure is much encouraged, by their imitation of their parents, or friends; who generally address them with a smiling countenance: and hence some nations are more remarkable for the gaiety, and others for the gravity of their looks. 5. _Of Anger._ The actions that constitute the mode of fighting, are the immediate language of anger in all animals; and a preparation for these actions is the natural language of threatening. Hence the human creature clenches his fist, and sternly surveys his adversary, as if meditating where to make the attack; the ram, and the bull, draws himself some steps backwards, and levels his horns; and the horse, as he most frequently fights by striking with his hinder feet, turns his heels to his foe, and bends back his ears, to listen out the place of his adversary, that the threatened blow may not be ineffectual. 6. _Of Attention._ The eye takes in at once but half our horizon, and that only in the day, and our smell informs us of no very distant objects, hence we confide principally in the organ of hearing to apprize us of danger: when we hear any the smallest sound, that we cannot immediately account for, our fears are alarmed, we suspend our steps, hold every muscle still, open our mouths a little, erect our ears, and listen to gain further information: and this by habit becomes the general language of attention to objects of sight, as well as of hearing; and even to the successive trains of our ideas. The natural language of violent pain, which is expressed by writhing the body, grinning, and screaming; and that of tumultuous pleasure, expressed in loud laughter; belong to Section XXXIV. on Diseases from Volition. IX. It must have already appeared to the reader, that all other animals, as well as man, are possessed of this natural language of the passions, expressed in signs or tones; and we shall endeavour to evince, that those animals, which have preserved themselves from being enslaved by mankind, and are associated in flocks, are also possessed of some artificial language, and of some traditional knowledge. The mother-turkey, when she eyes a kite hovering high in air, has either seen her own parents thrown into fear at his presence, or has by observation been acquainted with his dangerous designs upon her young. She becomes agitated with fear, and uses the natural language of that passion, her young ones catch the fear by imitation, and in an instant conceal themselves in the grass. At the same time that she shews her fears by her gesture and deportment, she uses a certain exclamation, Koe-ut, Koe-ut, and the young ones afterwards know, when they hear this note, though they do not see their dam, that the presence of their adversary is denounced, and hide themselves as before. The wild tribes of birds have very frequent opportunities of knowing their enemies, by observing the destruction they make among their progeny, of which every year but a small part escapes to maturity: but to our domestic birds these opportunities so rarely occur, that their knowledge of their distant enemies must frequently be delivered by tradition in the manner above explained, through many generations. This note of danger, as well as the other notes of the mother-turkey, when she calls her flock to their food, or to sleep under her wings, appears to be an artificial language, both as expressed by the mother, and as understood by the progeny. For a hen teaches this language with equal ease to the ducklings, she has hatched from suppositious eggs, and educates as her own offspring: and the wagtails, or hedge-sparrows, learn it from the young cuckoo their softer nursling, and supply him with food long after he can fly about, whenever they hear his cuckooing, which Linnæus tells us, is his call of hunger, (Syst. Nat.) And all our domestic animals are readily taught to come to us for food, when we use one tone of voice, and to fly from our anger, when we use another. Rabbits, as they cannot easily articulate sounds, and are formed into societies, that live under ground, have a very different method of giving alarm. When danger is threatened, they thump on the ground with one of their hinder feet, and produce a sound, that can be heard a great way by animals near the surface of the earth, which would seem to be an artificial sign both from its singularity and its aptness to the situation of the animal. The rabbits on the island of Sor, near Senegal, have white flesh, and are well tasted, but do not burrow in the earth, so that we may suspect their digging themselves houses in this cold climate is an acquired art, as well as their note of alarm, (Adanson's Voyage to Senegal). The barking of dogs is another curious note of alarm, and would seem to be an acquired language, rather than a natural sign: for "in the island of Juan Fernandes, the dogs did not attempt to bark, till some European dogs were put among them, and then they gradually begun to imitate them, but in a strange manner at first, as if they were learning a thing that was not natural to them," (Voyage to South America by Don G. Juan, and Don Ant. de Ulloa. B. 2. c. 4). Linnæus also observes, that the dogs of South America do not bark at strangers, (Syst. Nat.) And the European dogs, that have been carried to Guinea, are said in three or four generations to cease to bark, and only howl, like the dogs that are natives of that coast, (World Displayed, Vol. XVII. p. 26.) A circumstance not dissimilar to this, and equally curious, is mentioned by Kircherus, de Musurgia, in his Chapter de Lusciniis, "That the young nightingales, that are hatched under other birds, never sing till they are instructed by the company of other nightingales." And Jonston affirms, that the nightingales that visit Scotland, have not the same harmony as those of Italy, (Pennant's Zoology, octavo, p. 255); which would lead us to suspect that the singing of birds, like human music, is an artificial language rather than a natural expression of passion. X. Our music like our language, is perhaps entirely constituted of artificial tones, which by habit suggest certain agreeable passions. For the same combination of notes and tones do not excite devotion, love, or poetic melancholy in a native of Indostan and of Europe. And "the Highlander has the same warlike ideas annexed to the sound of a bagpipe (an instrument which an Englishman derides), as the Englishman has to that of a trumpet or fife," (Dr. Brown's Union of Poetry and Music, p. 58.) So "the music of the Turks is very different from the Italian, and the people of Fez and Morocco have again a different kind, which to us appears very rough and horrid, but is highly pleasing to them," (L'Arte Armoniaca a Giorgio Antoniotto). Hence we see why the Italian opera does not delight an untutored Englishman; and why those, who are unaccustomed to music, are more pleased with a tune, the second or third time they hear it, than the first. For then the same melodious train of sounds excites the melancholy, they had learned from the song; or the same vivid combination of them recalls all the mirthful ideas of the dance and company. Even the sounds, that were once disagreeable to us, may by habit be associated with other ideas, so as to become agreeable. Father Lasitau, in his account of the Iroquois, says "the music and dance of those Americans, have something in them extremely barbarous, which at first disgusts. We grow reconciled to them by degrees, and in the end partake of them with pleasure, the savages themselves are fond of them to distraction," (Moeurs des Savages, Tom. ii.) There are indeed a few sounds, that we very generally associate with agreeable ideas, as the whistling of birds, or purring of animals, that are delighted; and some others, that we as generally associate with disagreeable ideas, as the cries of animals in pain, the hiss of some of them in anger, and the midnight howl of beasts of prey. Yet we receive no terrible or sublime ideas from the lowing of a cow, or the braying of an ass. Which evinces, that these emotions are owing to previous associations. So if the rumbling of a carriage in the street be for a moment mistaken for thunder, we receive a sublime sensation, which ceases as soon as we know it is the noise of a coach and six. There are other disagreeable sounds, that are said to set the teeth on edge; which, as they have always been thought a necessary effect of certain discordant notes, become a proper subject of our enquiry. Every one in his childhood has repeatedly bit a part of the glass or earthen vessel, in which his food has been given him, and has thence had a very disagreeable sensation in the teeth, which sensation was designed by nature to prevent us from exerting them on objects harder than themselves. The jarring sound produced between the cup and the teeth is always attendant on this disagreeable sensation: and ever after when such a sound is accidentally produced by the conflict of two hard bodies, we feel by association of ideas the concomitant disagreeable sensation in our teeth. Others have in their infancy frequently held the corner of a silk handkerchief in their mouth, or the end of the velvet cape of their coat, whilst their companions in play have plucked it from them, and have given another disagreeable sensation to their teeth, which has afterwards recurred on touching those materials. And the sight of a knife drawn along a china plate, though no sound is excited by it, and even the imagination of such a knife and plate so scraped together, I know by repeated experience will produce the same disagreeable sensation of the teeth. These circumstances indisputably prove, that this sensation of the tooth-edge is owing to associated ideas; as it is equally excitable by sight, touch, hearing, or imagination. In respect to the artificial proportions of sound excited by musical instruments, those, who have early in life associated them with agreeable ideas, and have nicely attended to distinguish them from each other, are said to have a good ear, in that country where such proportions are in fashion: and not from any superior perfection in the organ of hearing, or any intuitive sympathy between certain sounds and passions. I have observed a child to be exquisitely delighted with music, and who could with great facility learn to sing any tune that he heard distinctly, and yet whole organ of hearing was so imperfect, that it was necessary to speak louder to him in common conversation than to others. Our music, like our architecture, seems to have no foundation in nature, they are both arts purely of human creation, as they imitate nothing. And the professors of them have only classed those circumstances, that are most agreeable to the accidental taste of their age, or country; and have called it Proportion. But this proportion must always fluctuate, as it rests on the caprices, that are introduced into our minds by our various modes of education. And these fluctuations of taste must become more frequent in the present age, where mankind have enfranchised themselves from the blind obedience to the rules of antiquity in perhaps every science, but that of architecture. See Sect. XII. 7. 3. XI. There are many articles of knowledge, which the animals in cultivated countries seem to learn very early in their lives, either from each other, or from experience, or observation: one of the most general of these is to avoid mankind. There is so great a resemblance in the natural language of the passions of all animals, that we generally know, when they are in a pacific, or in a malevolent humour, they have the same knowledge of us; and hence we can scold them from us by some tones and gestures, and could possibly attract them to us by others, if they were not already apprized of our general malevolence towards them. Mr. Gmelin, Professor at Petersburg, assures us, that in his journey into Siberia, undertaken by order of the Empress of Russia, he saw foxes, that expressed no fear of himself or companions, but permitted him to come quite near them, having never seen the human creature before. And Mr. Bongainville relates, that at his arrival at the Malouine, or Falkland's Islands, which were not inhabited by men, all the animals came about himself and his people; the fowls settling upon their heads and shoulders, and the quadrupeds running about their feet. From the difficulty of acquiring the confidence of old animals, and the ease of taming young ones, it appears that the fear, they all conceive at the sight of mankind, is an acquired article of knowledge. This knowledge is more nicely understood by rooks, who are formed into societies, and build, as it were, cities over our heads; they evidently distinguish, that the danger is greater when a man is armed with a gun. Every one has seen this, who in the spring of the year has walked under a rookery with a gun in his hand: the inhabitants of the trees rise on their wings, and scream to the unfledged young to shrink into their nests from the sight of the enemy. The vulgar observing this circumstance so uniformly to occur, assert that rooks can smell gun-powder. The fieldfares, (turdus pilarus) which breed in Norway, and come hither in the cold season for our winter berries; as they are associated in flocks, and are in a foreign country, have evident marks of keeping a kind of watch, to remark and announce the appearance of danger. On approaching a tree, that is covered with them, they continue fearless till one at the extremity of the bush rising on his wings gives a loud and peculiar note of alarm, when they all immediately fly, except one other, who continues till you approach still nearer, to certify as it were the reality of the danger, and then he also flies off repeating the note of alarm. And in the woods about Senegal there is a bird called uett-uett by the negroes, and squallers by the French, which, as soon as they see a man, set up a loud scream, and keep flying round him, as if their intent was to warn other birds, which upon hearing the cry immediately take wing. These birds are the bane of sportsmen, and frequently put me into a passion, and obliged me to shoot them, (Adanson's Voyage to Senegal, 78). For the same intent the lesser birds of our climate seem to fly after a hawk, cuckoo, or owl, and scream to prevent their companions from being surprised by the general enemies of themselves, or of their eggs and progeny. But the lapwing, (charadrius pluvialis Lin.) when her unfledged offspring run about the marshes, where they were hatched, not only gives the note of alarm at the approach of men or dogs, that her young may conceal themselves; but flying and screaming near the adversary, she appears more felicitous and impatient, as he recedes from her family, and thus endeavours to mislead him, and frequently succeeds in her design. These last instances are so apposite to the situation, rather than to the natures of the creatures, that use them; and are so similar to the actions of men in the same circumstances, that we cannot but believe, that they proceed from a similar principle. Miss M.E. Jacson acquainted me, that she witnessed this autumn an agreeable instance of sagacity in a little bird, which seemed to use the means to obtain an end; the bird repeatedly hopped upon a poppy-stem, and shook the head with its bill, till many seeds were scattered, then it settled on the ground, and eat the seeds, and again repeated the same management. Sept. 1, 1794. On the northern coast of Ireland a friend of mine saw above a hundred crows at once preying upon muscles; each crow took a muscle up into the air twenty or forty yards high, and let it fall on the stones, and thus by breaking the shell, got possession of the animal.--A certain philosopher (I think it was Anaxagoras) walking along the sea-shore to gather shells, one of these unlucky birds mistaking his bald head for a stone, dropped a shell-fish upon it, and killed at once a philosopher and an oyster. Our domestic animals, that have some liberty, are also possessed of some peculiar traditional knowledge: dogs and cats have been forced into each other's society, though naturally animals of a very different kind, and have hence learned from each other to eat dog's grass (agrostis canina) when they are sick, to promote vomiting. I have seen a cat mistake the blade of barley for this grass, which evinces it is an acquired knowledge. They have also learnt of each other to cover their excrement and urine;--about a spoonful of water was spilt upon my hearth from the tea-kettle, and I observed a kitten cover it with ashes. Hence this must also be an acquired art, as the creature mistook the application of it. To preserve their fur clean, and especially their whiskers, cats wash their faces, and generally quite behind their ears, every time they eat. As they cannot lick those places with their tongues, they first wet the inside of the leg with saliva, and then repeatedly wash their faces with it, which must originally be an effect of reasoning, because a means is used to produce an effect; and seems afterwards to be taught or acquired by imitation, like the greatest part of human arts. These animals seem to possess something like an additional sense by means of their whiskers; which have perhaps some analogy to the antennæ of moths and butterflies. The whiskers of cats consist not only of the long hairs on their upper lips, but they have also four or five long hairs standing up from each eyebrow, and also two or three on each cheek; all which, when the animal erects them, make with their points so many parts of the periphery of a circle, of an extent at least equal to the circumference of any part of their own bodies. With this instrument, I conceive, by a little experience, they can at once determine, whether any aperture amongst hedges or shrubs, in which animals of this genus live in their wild state, is large enough to admit their bodies; which to them is a matter of the greatest consequence, whether pursuing or pursued. They have likewise a power of erecting and bringing forward the whiskers on their lips; which probably is for the purpose of feeling, whether a dark hole be further permeable. The antennæ, or horns, of butterflies and moths, who have awkward wings, the minute feathers of which are very liable to injury, serve, I suppose, a similar purpose of measuring, as they fly or creep amongst the leaves of plants and trees, whither their wings can pass without touching them. Mr. Leonard, a very intelligent friend of mine, saw a cat catch a trout by darting upon it in a deep clear water at the mill at Weaford, near Lichfield. The cat belonged to Mr. Stanley, who had often seen her catch fish in the same manner in summer, when the mill-pool was drawn so low, that the fish could be seen. I have heard of other cats taking fish in shallow water, as they stood on the bank. This seems a natural art of taking their prey in cats, which their acquired delicacy by domestication has in general prevented them from using, though their desire of eating fish continues in its original strength. Mr. White, in his ingenious History of Selbourn, was witness to a cat's suckling a young hare, which followed her about the garden, and came jumping to her call of affection. At Elford, near Lichfield, the Rev. Mr. Sawley had taken the young ones out of a hare, which was shot; they were alive, and the cat, who had just lost her own kittens, carried them away, as it was supposed, to eat them; but it presently appeared, that it was affection not hunger which incited her, as she suckled them, and brought them up as their mother. Other instances of the mistaken application of what has been termed instinct may be observed in flies in the night, who mistaking a candle for day-light, approach and perish in the flame. So the putrid smell of the stapelia, or carrion-flower, allures the large flesh-fly to deposit its young worms on its beautiful petals, which perish there for want of nourishment. This therefore cannot be a necessary instinct, because the creature mistakes the application of it. Though in this country horses shew little vestiges of policy, yet in the deserts of Tartary, and Siberia, when hunted by the Tartars they are seen to form a kind of community, set watches to prevent their being surprised, and have commanders, who direct, and hasten their flight, Origin of Language, Vol. I. p. 212. In this country, where four or five horses travel in a line, the first always points his ears forward, and the last points his backward, while the intermediate ones seem quite careless in this respect; which seems a part of policy to prevent surprise. As all animals depend most on the ear to apprize them of the approach of danger, the eye taking in only half the horizon at once, and horses possess a great nicety of this sense; as appears from their mode of fighting mentioned No. 8. 5. of this Section, as well as by common observation. There are some parts of a horse, which he cannot conveniently rub, when they itch, as about the shoulder, which he can neither bite with his teeth, nor scratch with his hind foot; when this part itches, he goes to another horse, and gently bites him in the part which he wishes to be bitten, which is immediately done by his intelligent friend. I once observed a young foal thus bite its large mother, who did not choose to drop the grass she had in her mouth, and rubbed her nose against the foal's neck instead of biting it; which evinces that she knew the design of her progeny, and was not governed by a necessary instinct to bite where she was bitten. Many of our shrubs, which would otherwise afford an agreeable food to horses, are armed with thorns or prickles, which secure them from those animals; as the holly, hawthorn, gooseberry, gorse. In the extensive moorlands of Staffordshire, the horses have learnt to stamp upon a gorse-bush with one of their fore-feet for a minute together, and when the points are broken, they eat it without injury. The horses in the new forest in Hampshire are affirmed to do the same by Mr. Gilpin. Forest Scenery, II. 251, and 112. Which is an art other horses in the fertile parts of the country do not possess, and prick their mouths till they bleed, if they are induced by hunger or caprice to attempt eating gorse. Swine have a sense of touch as well as of smell at the end of their nose, which they use as a hand, both to root up the soil, and to turn over and examine objects of food, somewhat like the proboscis of an elephant. As they require shelter from the cold in this climate, they have learnt to collect straw in their mouths to make their nest, when the wind blows cold; and to call their companions by repeated cries to assist in the work, and add to their warmth by their numerous bedfellows. Hence these animals, which are esteemed so unclean, have also learned never to befoul their dens, where they have liberty, with their own excrement; an art, which cows and horses, which have open hovels to run into, have never acquired. I have observed great sagacity in swine; but the short lives we allow them, and their general confinement, prevents their improvement, which might probably be otherwise greater than that of dogs. Instances of the sagacity and knowledge of animals are very numerous to every observer, and their docility in learning various arts from mankind, evinces that they may learn similar arts from their own species, and thus be possessed of much acquired and traditional knowledge. A dog whose natural prey is sheep, is taught by mankind, not only to leave them unmolested, but to guard them; and to hunt, to set, or to destroy other kinds of animals, as birds, or vermin; and in some countries to catch fish, in others to find truffles, and to practise a great variety of tricks; is it more surprising that the crows should teach each other, that the hawk can catch less birds, by the superior swiftness of his wing, and if two of them follow him, till he succeeds in his design, that they can by force share a part of the capture? This I have formerly observed with attention and astonishment. There is one kind of pelican mentioned by Mr. Osbeck, one of Linnæus's travelling pupils (the pelicanus aquilus), whose food is fish; and which it takes from other birds, because it is not formed to catch them itself; hence it is called by the English a Man-of-war-bird, Voyage to China, p. 88. There are many other interesting anecdotes of the pelican and cormorant, collected from authors of the best authority, in a well-managed Natural History for Children, published by Mr. Galton. Johnson. London. And the following narration from the very accurate Mons. Adanson, in his Voyage to Senegal, may gain credit with the reader: as his employment in this country was solely to make observations in natural history. On the river Niger, in his road to the island Griel, he saw a great number of pelicans, or wide throats. "They moved with great state like swans upon the water, and are the largest bird next to the ostrich; the bill of the one I killed was upwards of a foot and half long, and the bag fastened underneath it held two and twenty pints of water. They swim in flocks, and form a large circle, which they contract afterwards, driving the fish before them with their legs: when they see the fish in sufficient number confined in this space, they plunge their bill wide open into the water, and shut it again with great quickness. They thus get fish into their throat-bag, which they eat afterwards on shore at their leisure." P. 247. XII. The knowledge and language of those birds, that frequently change their climate with the seasons, is still more extensive: as they perform these migrations in large societies, and are less subject to the power of man, than the resident tribes of birds. They are said to follow a leader during the day, who is occasionally changed, and to keep a continual cry during the night to keep themselves together. It is probable that these emigrations were at first undertaken as accident directed, by the more adventurous of their species, and learned from one another like the discoveries of mankind in navigation. The following circumstances strongly support this opinion. 1. Nature has provided these animals, in the climates where they are produced, with another resource: when the season becomes too cold for their constitutions, or the food they were supported with ceases to be supplied, I mean that of sleeping. Dormice, snakes, and bats, have not the means of changing their country; the two former from the want of wings, and the latter from his being not able to bear the light of the day. Hence these animals are obliged to make use of this resource, and sleep during the winter. And those swallows that have been hatched too late in the year to acquire their full strength of pinion, or that have been maimed by accident or disease, have been frequently found in the hollows of rocks on the sea coasts, and even under water in this torpid state, from which they have been revived by the warmth of a fire. This torpid state of swallows is testified by innumerable evidences both of antient and modern names. Aristotle speaking of the swallows says, "They pass into warmer climates in winter, if such places are at no great distance; if they are, they bury themselves in the climates where they dwell," (8. Hist. c. 16. See also Derham's Phys. Theol. v. ii. p. 177.) Hence their emigrations cannot depend on a _necessary_ instinct, as the emigrations themselves are not _necessary_. 2. When the weather becomes cold, the swallows in the neighbourhood assemble in large flocks; that is, the unexperienced attend those that have before experienced the journey they are about to undertake: they are then seen some time to hover on the coast, till there is calm whether, or a wind, that suits the direction of their flight. Other birds of passage have been drowned by thousands in the sea, or have settled on ships quite exhausted with fatigue. And others, either by mistaking their course, or by distress of weather, have arrived in countries where they were never seen before: and thus are evidently subject to the same hazards that the human species undergo, in the execution of their artificial purposes. 3. The same birds are emigrant from some countries and not so from others: the swallows were seen at Goree in January by an ingenious philosopher of my acquaintance, and he was told that they continued there all the year; as the warmth of the climate was at all seasons sufficient for their own constitutions, and for the production of the flies that supply them with nourishment. Herodotus says, that in Libya, about the springs of the Nile, the swallows continue all the year. (L. 2.) Quails (tetrao corturnix, Lin.) are birds of passage from the coast of Barbary to Italy, and have frequently settled in large shoals on ships fatigued with their flight. (Ray, Wisdom of God, p. 129. Derham. Physic. Theol. v. ii. p. 178,) Dr. Ruffel, in his History of Aleppo, observes that the swallows visit that country about the end of February, and having hatched their young disappear about the end of July; and returning again about the beginning of October, continue about a fortnight, and then again disappear. (P. 70.) When my late friend Dr. Chambres, of Derby, was on the island of Caprea in the bay of Naples, he was informed that great flights of quails annually settle on that island about the beginning of May, in their passage from Africa to Europe. And that they always come when the south-east wind blows, are fatigued when they rest on this island, and are taken in such amazing quantities and sold to the Continent, that the inhabitants pay the bishop his stipend out of the profits arising from the sale of them. The flights of these birds across the Mediterranean are recorded near three thousand years ago. "There went forth a wind from the Lord and brought quails from the sea, and let them fall upon the camp, a day's journey round about it, and they were two cubits above the earth," (Numbers, chap. ii. ver. 31.) In our country, Mr. Pennant informs us, that some quails migrate, and others only remove from the internal parts of the island to the coasts, (Zoology, octavo, 210.) Some of the ringdoves and stares breed here, others migrate, (ibid. 510, ii.) And the slender billed small birds do not all quit these kingdoms in the winter, though the difficulty of procuring the worms and insects, that they feed on, supplies the same reason for migration to them all, (ibid. 511.) Linnæus has observed, that in Sweden the female chaffinches quit that country in September, migrating into Holland, and leave their mates behind till their return in spring. Hence he has called them Fringilla cælebs, (Amæn. Acad. ii. 42. iv. 595.) Now in our climate both sexes of them are perennial birds. And Mr. Pennant observes that the hoopoe, chatterer, hawfinch, and crossbill, migrate into England so rarely, and at such uncertain times, as not to deserve to be ranked among our birds of passage, (ibid. 511.) The water fowl, as geese and ducks, are better adapted for long migrations, than the other tribes of birds, as, when the weather is calm, they can not only rest themselves, or sleep upon the ocean, but possibly procure some kind of food from it. Hence in Siberia, as soon as the lakes are frozen, the water fowl, which are very numerous, all disappear, and are supposed to fly to warmer climates, except the rail, which, from its inability for long flights, probably sleeps, like our bat, in their winter. The following account from the Journey of Professor Gmelin, may entertain the reader. "In the neighbourhood of Krasnoiark, amongst many other emigrant water fowls, we observed a great number of rails, which when pursued never took flight, but endeavoured to escape by running. We enquired how these birds, that could not fly, could retire into other countries in the winter, and were told, both by the Tartars and Assanians, that they well knew those birds could not alone pass into other countries: but when the cranes (les grues) retire in autumn, each one takes a rail (un rale) upon his back, and carries him to a warmer climate." _Recapitulation._ 1. All birds of passage can exist in the climates, where they are produced. 2. They are subject in their migrations to the same accidents and difficulties, that mankind are subject to in navigation. 3. The same species of birds migrate from some countries, and are resident in others. From all these circumstances it appears that the migrations of birds are not produced by a necessary instinct, but are accidental improvements, like the arts among mankind, taught by their cotemporaries, or delivered by tradition from one generation of them to another. XIII. In that season of the year which supplies the nourishment proper for the expected brood, the birds enter into a contract of marriage, and with joint labour construct a bed for the reception of their offspring. Their choice of the proper season, their contracts of marriage, and the regularity with which they construct their nests, have in all ages excited the admiration of naturalists; and have always been attributed to the power of instinct, which, like the occult qualities of the antient philosophers, prevented all further enquiry. We shall consider them in their order. _Their Choice of the Season._ Our domestic birds, that are plentifully supplied throughout the year with their adapted food, and are covered with houses from the inclemency of the weather, lay their eggs at any season: which evinces that the spring of the year is not pointed out to them by a necessary instinct. Whilst the wild tribes of birds choose this time of the year from their acquired knowledge, that the mild temperature of the air is more convenient for hatching their eggs, and is soon likely to supply that kind of nourishment, that is wanted for their young. If the genial warmth of the spring produced the passion of love, as it expands the foliage of trees, all other animals should feel its influence as well as birds: but, the viviparous creatures, as they suckle their young, that is, as they previously digest the natural food, that it may better suit the tender stomachs of their offspring, experience the influence of this passion at all seasons of the year, as cats and bitches. The graminivorous animals indeed generally produce their young about the time when grass is supplied in the greatest plenty, but this is without any degree of exactness, as appears from our cows, sheep, and hares, and may be a part of the traditional knowledge, which they learn from the example of their parents. _Their Contracts of Marriage._ Their mutual passion, and the acquired knowledge, that their joint labour is necessary to procure sustenance for their numerous family, induces the wild birds to enter into a contract of marriage, which does not however take place among the ducks, geese, and fowls, that are provided with their daily food from our barns. An ingenious philosopher has lately denied, that animals can enter into contracts, and thinks this an essential difference between them and the human creature:--but does not daily observation convince us, that they form contracts of friendship with each other, and with mankind? When puppies and kittens play together, is there not a tacit contract, that they will not hurt each other? And does not your favorite dog expect you should give him his daily food, for his services and attention to you? And thus barters his love for your protection? In the same manner that all contracts are made amongst men, that do not understand each others arbitrary language. _Construction of their Nests._ 1. They seem to be instructed how to build their nests from their observation of that, in which they were educated, and from their knowledge of those things, that are most agreeable to their touch in respect: to warmth, cleanliness, and stability. They choose their situations from their ideas of safety from their enemies, and of shelter from the weather. Nor is the colour of their nests a circumstance unthought of; the finches, that build in green hedges, cover their habitations with green moss; the swallow or martin, that builds against rocks and houses, covers her's with clay, whilst the lark chooses vegetable straw nearly of the colour of the ground she inhabits: by this contrivance, they are all less liable to be discovered by their adversaries. 2. Nor are the nests of the same species of birds constructed always of the same materials, nor in the same form; which is another circumstance that ascertains, that they are led by observation. In the trees before Mr. Levet's house in Lichfield, there are annually nests built by sparrows, a bird which usually builds under the tiles of houses, or the thatch of barns. Not finding such convenient situations for their nests, they build a covered nest bigger than a man's head, with an opening like a mouth at the side, resembling that of a magpie, except that it is built with straw and hay, and lined with feathers, and so nicely managed as to be a defence against both wind and rain. The following extract from a Letter of the Rev. Mr. J. Darwin, of Carleton Scroop in Lincolnshire, authenticates a curious fact of this kind. "When I mentioned to you the circumstance of crows or rooks building in the spire of Welbourn church, you expressed a desire of being well informed of the certainty of the fact. Welbourn is situated in the road from Grantham to Lincoln on the Cliff row; I yesterday took a ride thither, and enquired of the rector, Mr. Ridgehill, whether the report was true, that rooks built in the spire of his church. He assured me it was true, and that they had done so time immemorial, as his parishioners affirmed. There was a common tradition, he said, that formerly a rookery in some high trees adjoined the church yard, which being cut down (probably in the spring, the building season), the rooks removed to the church, and built their nests on the outside of the spire on the tops of windows, which by their projection a little from the spire made them convenient room, but that they built also on the inside. I saw two nests made with sticks on the outside, and in the spires, and Mr. Ridgehill said there were always a great many. "I spent the day with Mr. Wright, a clergyman, at Fulbeck, near Welbourn, and in the afternoon Dr. Ellis of Headenham, about two miles from Welbourn, drank tea at Mr. Wright's, who said he remembered, when Mr. Welby lived at Welbourn, that he received a letter from an acquaintance in the west of England, desiring an answer, whether the report of rooks building in Welbourn church was true, as a wager was depending on that subject; to which he returned an answer ascertaining the fact, and decided the wager." Aug. 30, 1794. So the jackdaw (corvus monedula) generally builds in church-steeples, or under the roofs of high houses; but at Selbourn, in Southamptonshire, where towers and steeples are not sufficiently numerous, these birds build in forsaken rabbit burrows. See a curious account of these subterranean nests in White's History of Selbourn, p. 59. Can the skilful change of architecture in these birds and the sparrows above mentioned be governed by instinct? Then they must have two instincts, one for common, and the other for extraordinary occasions. I have seen green worsted in a nest, which no where exists in nature: and the down of thistles in those nests, that were by some accident constructed later in the summer, which material could not be procured for the earlier nests: in many different climates they cannot procure the same materials, that they use in ours. And it is well known, that the canary birds, that are propagated in this country, and the finches, that are kept tame, will build their nests of any flexile materials, that are given them. Plutarch, in his Book on Rivers, speaking of the Nile, says, "that the swallows collect a material, when the waters recede, with which they form nests, that are impervious to water." And in India there is a swallow that collects a glutinous substance for this purpose, whose nest is esculent, and esteemed a principal rarity amongst epicures, (Lin. Syst. Nat.) Both these must be constructed of very different materials from those used by the swallows of our country. In India the birds exert more artifice in building their nests on account of the monkeys and snakes: some form their pensile nests in the shape of a purse, deep and open at top; others with a hole in the side; and others, still more cautious, with an entrance at the very bottom, forming their lodge near the summit. But the taylor-bird will not ever trust its nest to the extremity of a tender twig, but makes one more advance to safety by fixing it to the leaf itself. It picks up a dead leaf, and sews it to the side of a living one, its slender bill being its needle, and its thread some fine fibres; the lining consists of feathers, gossamer, and down; its eggs are white, the colour of the bird light yellow, its length three inches, its weight three sixteenths of an ounce; so that the materials of the nest, and the weight of the bird, are not likely to draw down an habitation so slightly suspended. A nest of this bird is preserved in the British Museum, (Pennant's Indian Zoology). This calls to one's mind the Mosaic account of the origin of mankind, the first dawning of art there ascribed to them, is that of sewing leaves together. For many other curious kinds of nests see Natural History for Children, by Mr. Galton. Johnson. London. Part I. p. 47. Gen. Oriolus. 3. Those birds that are brought up by our care, and have had little communication with others of their own species, are very defective in this acquired knowledge; they are not only very awkward in the construction of their nests, but generally scatter their eggs in various parts of the room or cage, where they are confined, and seldom produce young ones, till, by failing in their first attempt, they have learnt something from their own observation. 4. During the time of incubation birds are said in general to turn their eggs every day; some cover them, when they leave the nest, as ducks and geese; in some the male is said to bring food to the female, that she may have less occasion of absence, in others he is said to take her place, when she goes in quest of food; and all of them are said to leave their eggs a shorter time in cold weather than in warm. In Senegal the ostrich sits on her eggs only during the night, leaving them in the day to the heat of the sun; but at the Cape of Good Hope, where the heat is less, she sits on them day and night. If it should be asked, what induces a bird to sit weeks on its first eggs unconscious that a brood of young ones will be the product? The answer must be, that it is the same passion that induces the human mother to hold her offspring whole nights and days in her fond arms, and press it to her bosom, unconscious of its future growth to sense and manhood, till observation or tradition have informed her. 5. And as many ladies are too refined to nurse their own children, and deliver them to the care and provision of others; so is there one instance of this vice in the feathered world. The cuckoo in some parts of England, as I am well informed by a very distinct and ingenious gentleman, hatches and educates her own young; whilst in other parts she builds no nest, but uses that of some lesser bird, generally either of the wagtail, or hedge sparrow, and depositing one egg in it, takes no further care of her progeny. As the Rev. Mr. Stafford was walking in Glosop Dale, in the Peak of Derbyshire, he saw a cuckoo rise from its nest. The nest was on the stump of a tree, that had been some time felled, among some chips that were in part turned grey, so as much to resemble the colour of the bird, in this nest were two young cuckoos: tying a string about the leg of one of them, he pegged the other end of it to the ground, and very frequently for many days beheld the old cuckoo feed these her young, as he stood very near them. The following extract of a Letter from the Rev. Mr. Wilmot, of Morley, near Derby, strengthens the truth of the fact above mentioned, of the cuckoo sometimes making a nest, and hatching her own young. "In the beginning of July 1792, I was attending some labourers on my farm, when one of them said to me, "There is a bird's nest upon one of the Coal-slack Hills; the bird is now sitting, and is exactly like a cuckoo. They say that cuckoo's never hatch their own eggs, otherwise I should have sworn it was one." He took me to the spot, it was in an open fallow ground; the bird was upon the nest, I stood and observed her some time, and was perfectly satisfied it was a cuckoo; I then put my hand towards her, and she almost let me touch her before she rose from the nest, which she appeared to quit with great uneasiness, skimming over the ground in the manner that a hen partridge does when disturbed from a new hatched brood, and went only to a thicket about forty or fifty yards from the nest; and continued there as long as I staid to observe her, which was not many minutes. In the nest, which was barely a hole scratched out of the coal-slack in the manner of a plover's nest, I observed three eggs, but did not touch them. As I had labourers constantly at work in that field, I went thither every day, and always looked to see if the bird was there, but did not disturb her for seven or eight days, when I was tempted to drive her from the nest, and found _two_ young ones, that appeared to have been hatched some days, but there was no appearance of the third egg. I then mentioned this extraordinary circumstance (for such I thought it) to Mr. and Mrs. Holyoak of Bidford Grange, Warwickshire, and to Miss M. Willes, who were on a visit at my house, and who all went to see it. Very lately I reminded Mr. Holyoak of it, who told me he had a perfect recollection of the whole, and that, considering it a curiosity, he walked to look at it several times, was perfectly satisfied as to its being a cuckoo, and thought her more attentive to her young, than any other bird he ever observed, having always found her brooding her young. In about a week after I first saw the young ones, one of them was missing, and I rather suspected my plough-boys having taken it; though it might possibly have been taken by a hawk, some time when the old one was seeking food. I never found her off her nest but once, and that was the last time I saw the remaining young one, when it was almost full feathered. I then went from home for two or three days, and, when I returned, the young one was gone, which I take for granted had flown. Though during this time I frequently saw cuckoos in the thicket I mention, I never observed any one, that I supposed to be the cock-bird, paired with this hen." Nor is this a new observation, though it is entirely overlooked by the modern naturalists, for Aristotle speaking of the cuckoo, asserts that she sometimes builds her nest among broken rocks, and on high mountains, (L. 6. H. c. 1.) but adds in another place that she generally possesses the nest of another bird, (L. 6. H. c. 7.) And Niphus says that cuckoos rarely build for themselves, most frequently laying their eggs in the nests of other birds, (Gesner, L. 3. de Cuculo.) The Philosopher who is acquainted with these facts concerning the cuckoo, would seem to have very little _reason_ himself, if he could imagine this neglect of her young to be a necessary _instinct_! XIV. The deep recesses of the ocean are inaccessible to mankind, which prevents us from having much knowledge of the arts and government of its inhabitants. 1. One of the baits used by the fisherman is an animal called an Old Soldier, his size and form are somewhat like the craw-fish, with this difference, that his tail is covered with a tough membrane instead of a shell; and to obviate this defect, he seeks out the uninhabited shell of some dead fish, that is large enough to receive his tail, and carries it about with him as part of his clothing or armour. 2. On the coasts about Scarborough, where the haddocks, cods, and dog-fish, are in great abundance, the fishermen universally believe that the dog-fish make a line, or semicircle, to encompass a shoal of haddocks and cod, confining them within certain limits near the shore, and eating them as occasion requires. For the haddocks and cod are always found near the shore without any dog-fish among them, and the dog-fish further off without any haddocks or cod; and yet the former are known to prey upon the latter, and in some years devour such immense quantities as to render this fishery more expensive than profitable. 3. The remora, when he wishes to remove his situation, as he is a very slow swimmer, is content to take an outside place on whatever conveyance is going his way; nor can the cunning animal be tempted to quit his hold of a ship when she is sailing, not even for the lucre of a piece of pork, lest it should endanger the loss of his passage: at other times he is easily caught with the hook. 4. The crab-fish, like many other testaceous animals, annually changes its shell; it is then in a soft state, covered only with a mucous membrane, and conceals itself in holes in the sand or under weeds; at this place a hard shelled crab always stands centinel, to prevent the sea insects from injuring the other in its defenceless state; and the fishermen from his appearance know where to find the soft ones, which they use for baits in catching other fish. And though the hard shelled crab, when he is on this duty, advances boldly to meet the foe, and will with difficulty quit the field; yet at other times he shews great timidity, and has a wonderful speed in attempting his escape; and, if often interrupted, will pretend death like the spider, and watch an opportunity to sink himself into the sand, keeping only his eyes above. My ingenious friend Mr. Burdett, who favoured me with these accounts at the time he was surveying the coasts, thinks the commerce between the sexes takes place at this time, and inspires the courage of the creature. 5. The shoals of herrings, cods, haddocks, and other fish, which approach our shores at certain seasons, and quit them at other seasons without leaving one behind; and the salmon, that periodically frequent our rivers, evince, that there are vagrant tribes of fish, that perform as regular migrations as the birds of passage already mentioned. 6. There is a cataract on the river Liffey in Ireland about nineteen feet high: here in the salmon season many of the inhabitants amuse themselves in observing these fish leap up the torrent. They dart themselves quite out of the water as they ascend, and frequently fall back many times before they surmount it, and baskets made of twigs are placed near the edge of the stream to catch them in their fall. I have observed, as I have sat by a spout of water, which descends from a stone trough about two feet into a stream below, at particular seasons of the year, a great number of little fish called minums, or pinks, throw themselves about twenty times their own length out of the water, expecting to get into the trough above. This evinces that the storgee, or attention of the dam to provide for the offspring, is strongly exerted amongst the nations of fish, where it would seem to be the most neglected; as these salmon cannot be supposed to attempt so difficult and dangerous a task without being conscious of the purpose or end of their endeavours. It is further remarkable, that most of the old salmon return to the sea before it is proper for the young shoals to attend them, yet that a few old ones continue in the rivers so late, that they become perfectly emaciated by the inconvenience of their situation, and this apparently to guide or to protect the unexperienced brood. Of the smaller water animals we have still less knowledge, who nevertheless probably possess many superior arts; some of these are mentioned in Botanic Garden, P. I. Add. Note XXVII. and XXVIII. The nympha of the water-moths of our rivers, which cover themselves with cases of straw, gravel, and shell, contrive to make their habitations, nearly in equilibrium with the water; when too heavy, they add a bit of wood or straw; when too light, a bit of gravel. Edinb. Trans. All these circumstances bear a near resemblance to the deliberate actions of human reason. XV. We have a very imperfect acquaintance with the various tribes of insects: their occupations, manner of life, and even the number of their senses, differ from our own, and from each other; but there is reason to imagine, that those which possess the sense of touch in the most exquisite degree, and whole occupations require the most constant exertion of their powers, are induced with a greater proportion or knowledge and ingenuity. The spiders of this country manufacture nets of various forms, adapted to various situations, to arrest the flies that are their food; and some of them have a house or lodging-place in the middle of the net, well contrived for warmth, security, or concealment. There is a large spider in South America, who constructs nets of so strong a texture as to entangle small birds, particularly the humming bird. And in Jamaica there is another spider, who digs a hole in the earth obliquely downwards, about three inches in length, and one inch in diameter, this cavity she lines with a tough thick web, which when taken out resembles a leathern purse: but what is most curious, this house has a door with hinges, like the operculum of some sea shells; and herself and family, who tenant this nest, open and shut the door, whenever they pass or repass. This history was told me, and the nest with its operculum shewn me by the late Dr. Butt of Bath, who was some years physician in Jamaica. The production of these nets is indeed a part of the nature or conformation of the animal, and their natural use is to supply the place of wings, when she wishes to remove to another situation. But when she employs them to entangle her prey, there are marks of evident design, for she adapts the form of each net to its situation, and strengthens those lines, that require it, by joining others to the middle of them, and attaching those others to distant objects, with the same individual art, that is used by mankind in supporting the masts and extending the sails of ships. This work is executed with more mathematical exactness and ingenuity by the field spiders, than by those in our houses, as their constructions are more subjected to the injuries of dews and tempests. Besides the ingenuity shewn by these little creatures in taking their prey, the circumstance of their counterfeiting death, when they are put into terror, is truly wonderful; and as soon as the object of terror is removed, they recover and run away. Some beetles are also said to possess this piece of hypocrisy. The curious webs, or chords, constructed by some young caterpillars to defend themselves from cold, or from insects of prey; and by silk-worms and some other caterpillars, when they transmigrate into aureliæ or larvæ, have deservedly excited the admiration of the inquisitive. But our ignorance of their manner of life, and even of the number of their senses, totally precludes us from understanding the means by which they acquire this knowledge. The care of the salmon in choosing a proper situation for her spawn, the structure of the nests of birds, their patient incubation, and the art of the cuckoo in depositing her egg in her neighbour's nursery, are instances of great sagacity in those creatures: and yet they are much inferior to the arts exerted by many of the insect tribes on similar occasions. The hairy excrescences on briars, the oak apples, the blasted leaves of trees, and the lumps on the backs of cows, are situations that are rather produced than chosen by the mother insect for the convenience of her offspring. The cells of bees, wasps, spiders, and of the various coralline insects, equally astonish us, whether we attend to the materials or to the architecture. But the conduct of the ant, and of some species of the ichneumon fly in the incubation of their eggs, is equal to any exertion of human science. The ants many times in a day move their eggs nearer the surface of their habitation, or deeper below it, as the heat of the weather varies; and in colder days lie upon them in heaps for the purpose of incubation: if their mansion is too dry, they carry them to places where there is moisture, and you may distinctly see the little worms move and suck up the water. When too much moisture approaches their nest, they convey their eggs deeper in the earth, or to some other place of safety. (Swammerd. Epil. ad Hist. Insects, p. 153. Phil. Trans. No. 23. Lowthrop. V. 2. p. 7.) There is one species of ichneumon-fly, that digs a hole in the earth, and carrying into it two or three living caterpillars, deposits her eggs, and nicely closing up the nest leaves them there; partly doubtless to assist the incubation, and partly to supply food to her future young, (Derham. B. 4, c. 13. Aristotle Hist. Animal, L. 5. c. 20.) A friend of mine put about fifty large caterpillars collected from cabbages on some bran and a few leaves into a box, and covered it with gauze to prevent their escape. After a few days we saw, from more than three fourths of them, about eight or ten little caterpillars of the ichneumon-fly come out of their backs, and spin each a small cocoon of silk, and in a few days the large caterpillars died. This small fly it seems lays its egg in the back of the cabbage caterpillar, which when hatched preys upon the material, which is produced there for the purpose of making silk for the future nest of the cabbage caterpillar; of which being deprived, the creature wanders about till it dies, and thus our gardens are preserved by the ingenuity of this cruel fly. This curious property of producing a silk thread, which is common to some sea animals, see Botanic Garden, Part I. Note XXVII. and is designed for the purpose of their transformation as in the silk-worm, is used for conveying themselves from higher branches to lower ones of trees by some caterpillars, and to make themselves temporary nests or tents, and by the spider for entangling his prey. Nor is it strange that so much knowledge should be acquired by such small animals; since there is reason to imagine, that these insects have the sense of touch, either in their proboscis, or their antennæ, to a great degree of perfection; and thence may possess, as far as their sphere extends, as accurate knowledge, and as subtle invention, as the discoverers of human arts. XVI. 1. If we were better acquainted with the histories of those insects that are formed into societies, as the bees, wasps, and ants, I make no doubt but we should find, that their arts and improvements are not so similar and uniform as they now appear to us, but that they arose in the same manner from experience and tradition, as the arts of our own species; though their reasoning is from fewer ideas, is busied about fewer objects, and is exerted with less energy. There are some kinds of insects that migrate like the birds before mentioned. The locust of warmer climates has sometimes come over to England; it is shaped like a grasshopper, with very large wings, and a body above an inch in length. It is mentioned as coming into Egypt with an east wind, "The lord brought an east wind upon the land all that day and night, and in the morning the east wind brought the locusts, and covered the face of the earth, so that the land was dark," Exod. x. 13. The migrations of these insects are mentioned in another part of the scripture, "The locusts have no king, yet go they forth all of them in bands," Prov. xxx. 27. The accurate Mr. Adanson, near the river Gambia in Africa, was witness to the migration of these insects. "About eight in the morning, in the month of February, there suddenly arose over our heads a thick cloud, which darkened the air, and deprived us of the rays of the sun. We found it was a cloud of locusts raised about twenty or thirty fathoms from the ground, and covering an extent of several leagues; at length a shower of these insects descended, and after devouring every green herb, while they rested, again resumed their flight. This cloud was brought by a strong east-wind, and was all the morning in passing over the adjacent country." (Voyage to Senegal, 158.) In this country the gnats are sometimes seen to migrate in clouds, like the musketoes of warmer climates, and our swarms of bees frequently travel many miles, and are said in North America always to fly towards the south. The prophet Isaiah has a beautiful allusion to these migrations, "The Lord shall call the fly from the rivers of Egypt, and shall hiss for the bee that is in the land of Assyria," Isa. vii. 18. which has been lately explained by Mr. Bruce, in his travels to discover the source of the Nile. 2. I am well informed that the bees that were carried into Barbadoes, and other western islands, ceased to lay up any honey after the first year, as they found it not useful to them: and are now become very troublesome to the inhabitants of those islands by infesting their sugar houses; but those in Jamaica continue to make honey, as the cold north winds, or rainy seasons of that island, confine them at home for several weeks together. And the bees of Senegal, which differ from those of Europe only in size, make their honey not only superior to ours in delicacy of flavour, but it has this singularity, that it never concretes, but remains liquid as syrup, (Adanson). From some observations of Mr. Wildman, and of other people of veracity, it appears, that during the severe part of the winter season for weeks together the bees are quite benumbed and torpid from the cold, and do not consume any of their provision. This state of sleep, like that of swallows and bats, seems to be the natural resource of those creatures in cold climates, and the making of honey to be an artificial improvement. As the death of our hives of bees appears to be owning to their being kept so warm, as to require food when their stock is exhausted; a very observing gentleman at my request put two hives for many weeks into a dry cellar, and observed, during all that time, they did not consume any of their provision, for their weight did not decrease as it had done when they were kept in the open air. The same observation is made in the Annual Register for 1768, p. 113. And the Rev. Mr. White, in his Method of preserving Bees, adds, that those on the north side of his house consumed less honey in the winter than those on the south side. There is another observation on bees well ascertained, that they at various times, when the season begins to be cold, by a general motion of their legs as they hang in clusters produce a degree of warmth, which is easily perceptible by the hand. Hence by this ingenious exertion, they for a long time prevent the torpid state they would naturally fall into. According to the late observations of Mr. Hunter, it appears that the bee's-wax is not made from the dust of the anthers of flowers, which they bring home on their thighs, but that this makes what is termed bee-bread, and is used for the purpose of feeding the bee-maggots; in the same manner butterflies live on honey, but the previous caterpillar lives on vegetable leaves, while the maggots of large flies require flesh for their food, and those of the ichneumon fly require insects for their food. What induces the bee who lives on honey to lay up vegetable powder for its young? What induces the butterfly to lay its eggs on leaves, when itself feeds on honey? What induces the other flies to seek a food for their progeny different from what they consume themselves? If these are not deductions from their own previous experience or observation, all the actions of mankind must be resolved into instinct. 3. The dormouse consumes but little of its food during the rigour of the season, for they roll themselves up, or sleep, or lie torpid the greatest part of the time; but on warm sunny days experience a short revival, and take a little food, and then relapse into their former state." (Pennant Zoolog. p. 67.) Other animals, that sleep in winter without laying up any provender, are observed to go into their winter beds fat and strong, but return to day-light in the spring season very lean and feeble. The common flies sleep during the winter without any provision for their nourishment, and are daily revived by the warmth of the sun, or of our fires. These whenever they see light endeavour to approach it, having observed, that by its greater vicinity they get free from the degree of torpor, that the cold produces; and are hence induced perpetually to burn themselves in our candles: deceived, like mankind, by the misapplication of their knowledge. Whilst many of the subterraneous insects, as the common worms, seem to retreat so deep into the earth as not to be enlivened or awakened by the difference of our winter days; and stop up their holes with leaves or straws, to prevent the frosts from injuring them, or the centipes from devouring them. The habits of peace, or the stratagems of war, of these subterranean nations are covered from our view; but a friend of mine prevailed on a distressed worm to enter the hole of another worm on a bowling-green, and he presently returned much wounded about his head. And I once saw a worm rise hastily out of the earth into the sunshine, and observed a centipes hanging at its tail: the centipes nimbly quitted the tail, and seizing the worm about its middle cut it in half with its forceps, and preyed upon one part, while the other escaped. Which evinces they have design in stopping the mouths of their habitations. 4. The wasp of this country fixes his habitation under ground, that he may not be affected with the various changes of our climate; but in Jamaica he hangs it on the bough of a tree, where the seasons are less severe. He weaves a very curious paper of vegetable fibres to cover his nest, which is constructed on the same principle with that of the bee, but with a different material; but as his prey consists of flesh, fruits, and insects, which are perishable commodities, he can lay up no provender for the winter. M. de la Loubiere, in his relation of Siam, says, "That in a part of that kingdom, which lies open to great inundations, all the ants make their settlements upon trees; no ants' nests are to be seen any where else." Whereas in our country the ground is their only situation. From the scriptual account of these insects, one might be led to suspect, that in some climates they lay up a provision for the winter. Origen affirms the same, (Cont. Cels. L. 4.) But it is generally believed that in this country they do not, (Prov. vi. 6. xxx. 25.) The white ants of the coast of Africa make themselves pyramids eight or ten feet high, on a base of about the same width, with a smooth surface of rich clay, excessively hard and well built, which appear at a distance like an assemblage of the huts of the negroes, (Adanson). The history of these has been lately well described in the Philosoph. Transactions, under the name of termes, or termites. These differ very much from the nest of our large ant; but the real history of this creature, as well as of the wasp, is yet very imperfectly known. Wasps are said to catch large spiders, and to cut off their legs, and carry their mutilated bodies to their young, Dict. Raison. Tom. I. p. 152. One circumstance I shall relate which fell under my own eye, and shewed the power or reason in a wasp, as it is exercised among men. A wasp, on a gravel walk, had caught a fly nearly as large as himself; kneeling on the ground I observed him separate the tail and the head from the body part, to which the wings were attached. He then took the body part in his paws, and rose about two feet from the ground with it; but a gentle breeze wafting the wings of the fly turned him round in the air, and he settled again with his prey upon the gravel. I then distinctly observed him cut off with his mouth, first one of the wings, and then the other, after which he flew away with it unmolested by the wind. Go, thou sluggard, learn arts and industry from the bee, and from the ant! Go, proud reasoner, and call the worm thy sister! XVII. _Conclusion._ It was before observed how much the superior accuracy of our sense of touch contributes to increase our knowledge; but it is the greater energy and activity of the power of volition (as explained in the former Sections of this work) that marks mankind, and has given him the empire of the world. There is a criterion by which we may distinguish our voluntary acts or thoughts from those that are excited by our sensations: "The former are always employed about the _means_ to acquire pleasureable objects, or to avoid painful ones: while the latter are employed about the _possession_ of those that are already in our power." If we turn our eyes upon the fabric of our fellow animals, we find they are supported with bones, covered with skins, moved by muscles; that they possess the same senses, acknowledge the same appetites, and are nourished by the same aliment with ourselves; and we should hence conclude from the strongest analogy, that their internal faculties were also in some measure similar to our own. Mr. Locke indeed published an opinion, that other animals possessed no abstract or general ideas, and thought this circumstance was the barrier between the brute and the human world. But these abstracted ideas have been since demonstrated by Bishop Berkley, and allowed by Mr. Hume, to have no existence in nature, not even in the mind of their inventor, and we are hence necessitated to look for some other mark of distinction. The ideas and actions of brutes, like those of children, are almost perpetually produced by their present pleasures, or their present pains; and, except in the few instances that have been mentioned in this Section, they seldom busy themselves about the _means_ of procuring future bliss, or of avoiding future misery. Whilst the acquiring of languages, the making of tools, and the labouring for money; which are all only the _means_ of procuring pleasure; and the praying to the Deity, as another _means_ to procure happiness, are characteristic of human nature. * * * * * SECT. XVII. THE CATENATION OF MOTIONS. I. 1. _Catenations of animal motion._ 2. _Are produced by irritations, by sensations, by volitions._ 3. _They continue some time after they have been excited. Cause of catenation._ 4. _We can then exert our attention on other objects._ 5. _Many catenations of motions go on together._ 6. _Some links of the catenations of motions may be left out without disuniting the chain._ 7. _Interrupted circles of motion continue confusedly till they come to the part of the circle, where they were disturbed._ 8. _Weaker catenations are dissevered by stronger._ 9. _Then new catenations take place._ 10. _Much effort prevents their reuniting. Impediment of speech._ 11. _Trains more easily dissevered than circles._ 12. _Sleep destroys volition and external stimulus._ II. _Instances of various catenations in a young lady playing on the harpsichord._ III. 1. _What catenations are the strongest._ 2. _Irritations joined with associations from strongest connexions. Vital motions._ 3. _New links with increased force, cold fits of fever produced._ 4. _New links with decreased force. Cold bath._ 5. _Irritation joined with sensation. Inflammatory fever. Why children cannot tickle themselves. 6. Volition joined with sensation. Irritative ideas of sound become sensible._ 7. _Ideas of imagination, dissevered by irritations, by volition, production of surprise._ I. 1. To investigate with precision the catenations of animal motions, it would be well to attend to the manner of their production; but we cannot begin this disquisition early enough for this purpose, as the catenations of motion seem to begin with life, and are only extinguishable with it; We have spoken of the power of irritation, of sensation, of volition, and of association, as preceding the fibrous motions; we now step forwards, and consider, that conversely they are in their turn preceded by those motions; and that all the successive trains or circles of our actions are composed of this twofold concatenation. Those we shall call trains of action, which continue to proceed without any stated repetitions; and those circles of action, when the parts of them return at certain periods, though the trains, of which they consist, are not exactly similar. The reading an epic poem is a train of actions; the reading a song with a chorus at equal distances in the measure constitutes so many circles of action. 2. Some catenations of animal motion are produced by reiterated successive irritations, as when we learn to repeat the alphabet in its order by frequently reading the letters of it. Thus the vermicular motions of the bowels were originally produced by the successive irritations of the passing aliment; and the succession of actions of the auricles and ventricles of the heart was originally formed by successive stimulus of the blood, these afterwards become part of the diurnal circles of animal actions, as appears by the periodical returns of hunger, and the quickened pulse of weak people in the evening. Other catenations of animal motion are gradually acquired by successive agreeable sensations, as in learning a favourite song or dance; others by disagreeable sensations, as in coughing or nictitation; these become associated by frequent repetition, and afterwards compose parts of greater circles of action like those above mentioned. Other catenations of motions are gradually acquired by frequent voluntary repetitions; as when we deliberately learn to march, read, fence, or any mechanic art, the motions of many of our muscles become gradually linked together in trains, tribes, or circles of action. Thus when any one at first begins to use the tools in turning wood or metals in a lathe, he wills the motions of his hand or fingers, till at length these actions become so connected with the effect, that he seems only to will the point of the chisel. These are caused by volition, connected by association like those above described, and afterwards become parts of our diurnal trains or circles of action. 3. All these catenations of animal motions, are liable to proceed some time after they are excited, unless they are disturbed or impeded by other irritations, sensations, or volitions; and in many instances in spite of our endeavours to stop them; and this property of animal motions is probably the cause of their catenation. Thus when a child revolves some minute on one foot, the spectra of the ambient objects appear to circulate round him some time after he falls upon the ground. Thus the palpitation of the heart continues some time after the object of fear, which occasioned it, is removed. The blush of shame, which is an excess of sensation, and the glow of anger, which is an excess of volition, continue some time, though the affected person finds, that those emotions were caused by mistaken facts, and endeavours to extinguish their appearance. See Sect. XII. 1. 5. 4. When a circle of motions becomes connected, by frequent repetitions as above, we can exert our attention strongly on other objects, and the concatenated circle of motions will nevertheless proceed in due order; as whilst you are thinking on this subject, you use variety of muscles in walking about your parlour, or in sitting at your writing-table. 5. Innumerable catenations of motions may proceed at the same time, without incommoding each other. Of these are the motions of the heart and arteries; those of digestion and glandular secretion; of the ideas, or sensual motions; those of progression, and of speaking; the great annual circle of actions so apparent in birds in their times of breeding and moulting; the monthly circles of many female animals; and the diurnal circles of sleeping and waking, of fulness and inanition. 6. Some links of successive trains or of synchronous tribes of action may be left out without disjoining the whole. Such are our usual trains of recollection; after having travelled through an entertaining country, and viewed many delightful lawns, rolling rivers, and echoing rocks; in the recollection of our journey we leave out the many districts, that we crossed, which were marked with no peculiar pleasure. Such also are our complex ideas, they are catenated tribes of ideas, which do not perfectly resemble their correspondent perceptions, because some of the parts are omitted. 7. If an interrupted circle of actions is not entirely dissevered, it will continue to proceed confusedly, till it comes to the part of the circle, where it was interrupted. The vital motions in a fever from drunkenness, and in other periodical diseases, are instances of this circumstance. The accidental inebriate does not recover himself perfectly till about the same hour on the succeeding day. The accustomed drunkard is disordered, if he has not his usual potation of fermented liquor. So if a considerable part of a connected tribe of action be disturbed, that whole tribe goes on with confusion, till the part of the tribe affected regains its accustomed catenations. So vertigo produces vomiting, and a great secretion of bile, as in sea-sickness, all these being parts of the tribe of irritative catenations. 8. Weaker catenated trains may be dissevered by the sudden exertion of the stronger. When a child first attempts to walk across a room, call to him, and he instantly falls upon the ground. So while I am thinking over the virtues of my friends, if the tea-kettle spurt out some hot water on my stocking; the sudden pain breaks the weaker chain of ideas, and introduces a new group of figures of its own. This circumstance is extended to some unnatural trains of action, which have not been confirmed by long habit; as the hiccough, or an ague-fit, which are frequently curable by surprise. A young lady about eleven years old had for five days had a contraction of one muscle in her fore arm, and another in her arm, which occurred four or five times every minute; the muscles were seen to leap, but without bending the arm. To counteract this new morbid habit, an issue was placed over the convulsed muscle of her arm, and an adhesive plaster wrapped tight like a bandage over the whole fore arm, by which the new motions were immediately destroyed, but the means were continued some weeks to prevent a return. 9. If any circle of actions is dissevered, either by omission of some of the links, as in sleep, or by insertion of other links, as in surprise, new catenations take place in a greater or less degree. The last link of the broken chain of actions becomes connected with the new motion which has broken it, or with that which was nearest the link omitted; and these new catenations proceed instead of the old ones. Hence the periodic returns of ague-fits, and the chimeras of our dreams. 10. If a train of actions is dissevered, much effort of volition or sensation will prevent its being restored. Thus in the common impediment of speech, when the association of the motions of the muscles of enunciation with the idea of the word to be spoken is disordered, the great voluntary efforts, which distort the countenance, prevent the rejoining of the broken associations. See No. II. 10. of this Section. It is thus likewise observable in some inflammations of the bowels, the too strong efforts made by the muscles to carry forwards the offending material fixes it more firmly in its place, and prevents the cure. So in endeavouring to recal to our memory some particular word of a sentence, if we exert ourselves too strongly about it, we are less likely to regain it. 11. Catenated trains or tribes of action are easier dissevered than catenated circles of action. Hence in epileptic fits the synchronous connected tribes of action, which keep the body erect, are dissevered, but the circle of vital motions continues undisturbed. 12. Sleep destroys the power of volition, and precludes the stimuli of external objects, and thence dissevers the trains, of which these are a part; which confirms the other catenations, as those of the vital motions, secretions, and absorptions; and produces the new trains of ideas, which constitute our dreams. II. 1. All the preceding circumstances of the catenations of animal motions will be more clearly understood by the following example of a person learning music; and when we recollect the variety of mechanic arts, which are performed by associated trains of muscular actions catenated with the effects they produce, as in knitting, netting, weaving; and the greater variety of associated trains of ideas caused or catenated by volitions or sensations, as in our hourly modes of reasoning, or imagining, or recollecting, we shall gain some idea of the innumerable catenated trains and circles of action, which form the tenor of our lives, and which began, and will only cease entirely with them. 2. When a young lady begins to learn music, she voluntarily applies herself to the characters of her music-book, and by many repetitions endeavours to catenate them with the proportions of sound, of which they are symbols. The ideas excited by the musical characters are slowly connected with the keys of the harpsichord, and much effort is necessary to produce every note with the proper finger, and in its due place and time; till at length a train of voluntary exertions becomes catenated with certain irritations. As the various notes by frequent repetitions become connected in the order, in which they are produced, a new catenation of sensitive exertions becomes mixed with the voluntary ones above described; and not only the musical symbols of crotchets and quavers, but the auditory notes and tones at the same time, become so many successive or synchronous links in this circle of catenated actions. At length the motions of her fingers become catenated with the musical characters; and these no sooner strike the eye, than the finger presses down the key without any voluntary attention between them; the activity of the hand being connected with the irritation of the figure or place of the musical symbol on the retina; till at length by frequent repetitions of the same tune the movements of her fingers in playing, and the muscles of the larynx in singing, become associated with each other, and form part of those intricate trains and circles of catenated motions, according with the second article of the preceding propositions in No. 1. of this Section. 3. Besides the facility, which by habit attends the execution of this musical performance, a curious circumstance occurs, which is, that when our young musician has began a tune, she finds herself inclined to continue it; and that even when she is carelessly singing alone without attending to her own song; according with the third preceding article. 4. At the same time that our young performer continues to play with great exactness this accustomed tune, she can bend her mind, and that intensely, on some other object, according with the fourth article of the preceding proportions. The manuscript copy of this work was lent to many of my friends at different times for the purpose of gaining their opinions and criticisms on many parts of it, and I found the following anecdote written with a pencil opposite to this page, but am not certain by whom. "I remember seeing the pretty young actress, who succeeded Mrs. Arne in the performance of the celebrated Padlock, rehearse the musical parts at her harpsichord under the eye of her master with great taste and accuracy; though I observed her countenance full of emotion, which I could not account for; at last she suddenly burst into tears; for she had all this time been eyeing a beloved canary bird, suffering great agonies, which at that instant fell dead from its perch." 5. At the same time many other catenated circles of action are going on in the person of our fair musician, as well as the motions of her fingers, such as the vital motions, respiration, the movements of her eyes and eyelids, and of the intricate muscles of vocality, according with the fifth preceding article. 6. If by any strong impression on the mind of our fair musician she should be interrupted for a very inconsiderable time, she can still continue her performance, according to the sixth article. 7. If however this interruption be greater, though the chain of actions be not dissevered, it proceeds confusedly, and our young performer continues indeed to play, but in a hurry without accuracy and elegance, till she begins the tune again, according to the seventh of the preceding articles. 8. But if this interruption be still greater, the circle of actions becomes entirely dissevered, and she finds herself immediately under the necessity to begin over again to recover the lost catenation, according to the eighth preceding article. 9. Or in trying to recover it she will sing some dissonant notes, or strike some improper keys, according to the ninth preceding article. 10. A very remarkable thing attends this breach of catenation, if the performer has forgotten some word of her song, the more energy of mind she uses about it, the more distant is she from regaining it; and artfully employs her mind in part on some other object, or endeavours to dull its perceptions, continuing to repeat, as it were inconsciously, the former part of the song, that she remembers, in hopes to regain the lost connexion. For if the activity of the mind itself be more energetic, or takes its attention more, than the connecting word, which is wanted; it will not perceive the slighter link of this lost word; as who listens to a feeble sound, must be very silent and motionless; so that in this case the very vigour of the mind itself seems to prevent it from regaining the lost catenation, as well as the too great exertion in endeavouring to regain it, according to the tenth preceding article. We frequently experience, when we are doubtful about the spelling of a word, that the greater voluntary exertion we use, that is the more intensely we think about it, the further are we from regaining the lost association between the letters of it, but which readily recurs when we have become careless about it. In the same manner, after having for an hour laboured to recollect the name of some absent person, it shall seem, particularly after sleep, to come into the mind as it were spontaneously; that is the word we are in search of, was joined to the preceding one by association; this association being dissevered, we endeavour to recover it by volition; this very action of the mind strikes our attention more, than the faint link of association, and we find it impossible by this means to retrieve the lost word. After sleep, when volition is entirely suspended, the mind becomes capable of perceiving the fainter link of association, and the word is regained. On this circumstance depends the impediment of speech before mentioned; the first syllable of a word is causable by volition, but the remainder of it is in common conversation introduced by its associations with this first syllable acquired by long habit. Hence when the mind of the stammerer is vehemently employed on some idea of ambition of shining, or fear of not succeeding, the associations of the motions of the muscles of articulation with each other become dissevered by this greater exertion, and he endeavours in vain by voluntary efforts to rejoin the broken association. For this purpose he continues to repeat the first syllable, which is causable by volition, and strives in vain, by various distortions of countenance, to produce the next links, which are subject to association. See Class IV. 3. 1. 1. 11. After our accomplished musician has acquired great variety of tunes and songs, so that some of them begin to cease to be easily recollected, she finds progressive trains of musical notes more frequently forgotten, than those which are composed of reiterated circles, according with the eleventh preceding article. 12. To finish our example with the preceding articles we must at length suppose, that our fair performer falls asleep over her harpsichord; and thus by the suspension of volition, and the exclusion of external stimuli, she dissevers the trains and circles of her musical exertions. III. 1. Many of these circumstances of catenations of motions receive an easy explanation from the four following consequences to the seventh law of animal causation in Sect. IV. These are, first, that those successions or combinations of animal motions, whether they were united by causation, association, or catenation, which have been most frequently repeated, acquire the strongest connection. Secondly, that of these, those, which have been less frequently mixed with other trains or tribes of motion, have the strongest connection. Thirdly, that of these, those, which were first formed, have the strongest connection. Fourthly, that if an animal motion be excited by more than one causation, association, or catenation, at the same time, it will be performed with greater energy. 2. Hence also we understand, why the catenations of irritative motions are more strongly connected than those of the other classes, where the quantity of unmixed repetition has been equal; because they were first formed. Such are those of the secerning and absorbent systems of vessels, where the action of the gland produces a fluid, which stimulates the mouths of its correspondent absorbents. The associated motions seem to be the next most strongly united, from their frequent repetition; and where both these circumstances unite, as in the vital motions, their catenations are indissoluble but by the destruction of the animal. 3. Where a new link has been introduced into a circle of actions by some accidental defect of stimulus; if that defect of stimulus be repeated at the same part of the circle a second or a third time, the defective motions thus produced, both by the repeated defect of stimulus and by their catenation with the parts of the circle of actions, will be performed with less and less energy. Thus if any person is exposed to cold at a certain hour to-day, so long as to render some part of the system for a time torpid; and is again exposed to it at the same hour to-morrow, and the next day; he will be more and more affected by it, till at length a cold fit of fever is completely formed, as happens at the beginning of many of those fevers, which are called nervous or low fevers. Where the patient has slight periodical shiverings and paleness for many days before the febrile paroxysm is completely formed. 4. On the contrary, if the exposure to cold be for so short a time, as not to induce any considerable degree of torpor or quiescence, and is repeated daily as above mentioned, it loses its effect more and more at every repetition, till the constitution can bear it without inconvenience, or indeed without being conscious of it. As in walking into the cold air in frosty weather. The same rule is applicable to increased stimulus, as of heat, or of vinous spirit, within certain limits, as is applied in the two last paragraphs to Deficient Stimulus; as is further explained in Sect. XXXVI. on the Periods of Diseases. 5. Where irritation coincides with sensation to produce the same catenations of motion, as in inflammatory fevers, they are excited with still greater energy than by the irritation alone. So when children expect to be tickled in play, by a feather lightly passed over the lips, or by gently vellicating the soles of their feet, laughter is most vehemently excited; though they can stimulate these parts with their own fingers unmoved. Here the pleasureable idea of playfulness coincides with the vellication; and there is no voluntary exertion used to diminish the sensation, as there would be, if a child should endeavour to tickle himself. See Sect. XXXIV. 1. 4. 6. And lastly, the motions excited by the junction of voluntary exertion with irritation are performed with more energy, than those by irritation singly; as when we listen to small noises, as to the ticking of a watch in the night, we perceive the most weak sounds, that are at other times unheeded. So when we attend to the irritative ideas of sound in our ears, which are generally not attended to, we can hear them; and can see the spectra of objects, which remain in the eye, whenever we please to exert our voluntary power in aid of those weak actions of the retina, or of the auditory nerve. 7. The temporary catenations of ideas, which are caused by the sensations of pleasure or pain, are easily dissevered either by irritations, as when a sudden noise disturbs a day-dream; or by the power of volition, as when we awake from sleep. Hence in our waking hours, whenever an idea occurs, which is incongruous to our former experience, we instantly dissever the train of imagination by the power of volition, and compare the incongruous idea with our previous knowledge of nature, and reject it. This operation of the mind has not yet acquired a specific name, though it is exerted every minute of our waking hours; unless it may be termed INTUITIVE ANALOGY. It is an act of reasoning of which we are unconscious except from its effects in preserving the congruity of our ideas, and bears the same relation to the sensorial power of volition, that irritative ideas, of which we are inconscious except by their effects, do to the sensorial power of irritation; as the former is produced by volition without our attention to it, and the latter by irritation without our attention to them. If on the other hand a train of imagination or of voluntary ideas are excited with great energy, and passing on with great vivacity, and become dissevered by some violent stimulus, as the discharge of a pistol near one's ear, another circumstance takes place, which is termed SURPRISE; which by exciting violent irritation, and violent sensation, employs for a time the whole sensorial energy, and thus dissevers the passing trains of ideas, before the power of volition has time to compare them with the usual phenomena of nature. In this case fear is generally the companion of surprise, and adds to our embarrassment, as every one experiences in some degree when he hears a noise in the dark, which he cannot instantly account for. This catenation of fear with surprise is owing to our perpetual experience of injuries from external bodies in motion, unless we are upon our guard against them. See Sect. XVIII. 17. XIX. 2. Many other examples of the catenations of animal motions are explained in Sect. XXXVI. on the Periods of Diseases. * * * * * SECT. XVIII. OF SLEEP. 1. _Volition is suspended in sleep._ 2. _Sensation continues. Dreams prevent delirium and inflammation._ 3. _Nightmare._ 4. _Ceaseless flow of ideas in dreams._ 5. _We seem to receive them by the senses. Optic nerve perfectly sensible in sleep. Eyes less dazzled after dreaming of visible objects._ 6. _Reverie, belief._ 7. _How we distinguish ideas from perceptions._ 8. _Variety of scenery in dreams, excellence of the sense of vision._ 9. _Novelty of combination in dreams._ 10. _Distinctness of imagery in dreams._ 11. _Rapidity of transaction in dreams._ 12. _Of measuring time. Of dramatic time and place. Why a dull play induces sleep, and an interesting one reverie._ 13. _Consciousness of our existence and identity in dreams._ 14. _How we awake sometimes suddenly, sometimes frequently._ 15. _Irritative motions continue in sleep, internal irritations are succeeded by sensation. Sensibility increases during sleep, and irritability. Morning dreams. Why epilepsies occur in sleep. Ecstacy of children. Case of convulsions in sleep. Cramp, why painful. Asthma. Morning sweats. Increase of heat. Increase of urine in sleep. Why more liable to take cold in sleep. Catarrh from thin night-caps. Why we feel chilly at the approach of sleep, and at waking in the open air._ 16. _Why the gout commences in sleep. Secretions are more copious in sleep, young animals and plants grow more in sleep._ 17. _Inconsistency of dreams. Absence of surprise in dreams._ 18. _Why we forget some dreams and not others._ 19. _Sleep-talkers awake with surprise._ 20. _Remote causes of sleep. Atmosphere with less oxygene. Compression of the brain in spina bifida. By whirling on an horizontal wheel. By cold._ 21. _Definition of sleep._ 1. There are four situations of our system, which in their moderate degrees are not usually termed diseases, and yet abound with many very curious and instructive phenomena; these are sleep, reverie, vertigo, drunkenness. These we shall previously consider, before we step forwards to develop the causes and cures of diseases with the modes of the operation of medicines. As all those trains and tribes of animal motion, which are subjected to volition, were the last that were caused, their connection is weaker than that of the other classes; and there is a peculiar circumstance attending this causation, which is, that it is entirely suspended during sleep; whilst the other classes of motion, which are more immediately necessary to life, as those caused by internal stimuli, for instance the pulsations of the heart and arteries, or those catenated with pleasurable sensation, as the powers of digestion, continue to strengthen their habits without interruption. Thus though man in his sleeping state is a much less perfect animal, than in his waking hours; and though he consumes more than one third of his life in this his irrational situation; yet is the wisdom of the Author of nature manifest even in this seeming imperfection of his work! The truth of this assertion with respect to the large muscles of the body, which are concerned in locomotion, is evident; as no one in perfect sanity walks about in his sleep, or performs any domestic offices: and in respect to the mind, we never exercise our reason or recollection in dreams; we may sometimes seem distracted between contending passions, but we never compare their objects, or deliberate about the acquisition of those objects, if our sleep is perfect. And though many synchronous tribes or successive trains of ideas may represent the houses or walks, which have real existence, yet are they here introduced by their connection with our sensations, and are in truth ideas of imagination, not of recollection. 2. For our sensations of pleasure and pain are experienced with great vivacity in our dreams; and hence all that motley group of ideas, which are caused by them, called the ideas of imagination, with their various associated trains, are in a very vivid manner acted over in the sensorium; and these sometimes call into action the larger muscles, which have been much associated with them; as appears from the muttering sentences, which some people utter in their dreams, and from the obscure barking of sleeping dogs, and the motions of their feet and nostrils. This perpetual flow of the trains of ideas, which constitute our dreams, and which are caused by painful or pleasurable sensation, might at first view be conceived to be an useless expenditure of sensorial power. But it has been shewn, that those motions, which are perpetually excited, as those of the arterial system by the stimulus of the blood, are attended by a great accumulation of sensorial power, after they have been for a time suspended; as the hot-fit of fever is the consequence of the cold one. Now as these trains of ideas caused by sensation are perpetually excited during our waking hours, if they were to be suspended in sleep like the voluntary motions, (which are exerted only by intervals during our waking hours,) an accumulation of sensorial power would follow; and on our awaking a delirium would supervene, since these ideas caused by sensation would be produced with such energy, that we should mistake the trains of imagination for ideas excited by irritation; as perpetually happens to people debilitated by fevers on their first awaking; for in these fevers with debility the general quantity of irritation being diminished, that of sensation is increased. In like manner if the actions of the stomach, intestines, and various glands, which are perhaps in part at least caused by or catenated with agreeable sensation, and which perpetually exist during our waking hours, were like the voluntary motions suspended in our sleep; the great accumulation of sensorial power, which would necessarily follow, would be liable to excite inflammation in them. 3. When by our continued posture in sleep, some uneasy sensations are produced, we either gradually awake by the exertion of volition, or the muscles connected by habit with such sensations alter the position of the body; but where the sleep is uncommonly profound, and those uneasy sensations great, the disease called the incubus, or nightmare, is produced. Here the desire of moving the body is painfully exerted, by the power of moving it, or volition, is incapable of action, till we awake. Many less disagreeable struggles in our dreams, as when we wish in vain to fly from terrifying objects, constitute a slighter degree of this disease. In awaking from the nightmare I have more than once observed, that there was no disorder in my pulse; nor do I believe the respiration is laborious, as some have affirmed. It occurs to people whose sleep is too profound, and some disagreeable sensation exists, which at other times would have awakened them, and have thence prevented the disease of nightmare; as after great fatigue or hunger with too large a supper and wine, which occasion our sleep to be uncommonly profound. See No. 14, of this Section. 4. As the larger muscles of the body are much more frequently excited by volition than by sensation, they are but seldom brought into action in our sleep: but the ideas of the mind are by habit much more frequently connected with sensation than with volition; and hence the ceaseless flow of our ideas in dreams. Every one's experience will teach him this truth, for we all daily exert much voluntary muscular motion: but few of mankind can bear the fatigue of much voluntary thinking. 5. A very curious circumstance attending these our sleeping imaginations is, that we seem to receive them by the senses. The muscles, which are subservient to the external organs of sense, are connected with volition, and cease to act in sleep; hence the eyelids are closed, and the tympanum of the ear relaxed; and it is probable a similarity of voluntary exertion may be necessary for the perceptions of the other nerves of sense; for it is observed that the papillæ of the tongue can be seen to become erected, when we attempt to taste any thing extremely grateful. Hewson Exper. Enquir. V. 2. 186. Albini Annot. Acad. L. i. c. 15. Add to this, that the immediate organs of sense have no objects to excite them in the darkness and silence of the night, but their nerves of sense nevertheless continue to possess their perfect activity subservient to all their numerous sensitive connections. This vivacity of our nerves of sense during the time of sleep is evinced by a circumstance, which almost every one must at some time or other have experienced; that is, if we sleep in the daylight, and endeavour to see some object in our dream, the light is exceedingly painful to our eyes; and after repeated struggles we lament in our sleep, that we cannot see it. In this case I apprehend the eyelid is in some degree opened by the vehemence of our sensations; and, the iris being dilated, the optic nerve shews as great or greater sensibility than in our waking hours. See No. 15. of this Section. When we are forcibly waked at midnight from profound sleep, our eyes are much dazzled with the light of the candle for a minute or two, after there has been sufficient time allowed for the contraction of the iris; which is owing to the accumulation of sensorial power in the organ of vision during its state of less activity. But when we have dreamt much of visible objects, this accumulation of sensorial power in the organ of vision is lessened or prevented, and we awake in the morning without being dazzled with the light, after the iris has had time to contract itself. This is a matter of great curiosity, and may be thus tried by any one in the day-light. Close your eyes, and cover them with your hat; think for a minute on a tune, which you are accustomed to, and endeavour to sing it with as little activity of mind as possible. Suddenly uncover and open your eyes, and in one second of time the iris will contract itself, but you will perceive the day more luminous for several seconds, owing to the accumulation of sensorial power in the optic nerve. Then again close and cover your eyes, and think intensely on a cube of ivory two inches diameter, attending first to the north and south sides of it, and then to the other four sides of it; then get a clear image in your mind's eye of all the sides of the same cube coloured red; and then of it coloured green; and then of it coloured blue; lastly, open your eyes as in the former experiment, and after the first second of time allowed for the contraction of the iris, you will not perceive any increase of the light of the day, or dazzling; because now there is no accumulation of sensorial power in the optic nerve; that having been expended by its action in thinking over visible objects. This experiment is not easy to be made at first, but by a few patient trials the fact appears very certain; and shews clearly, that our ideas of imagination are repetitions of the motions of the nerve, which were originally occasioned by the stimulus of external bodies; because they equally expend the sensorial power in the organ of sense. See Sect. III. 4. which is analogous to our being as much fatigued by thinking as by labour. 6. Nor is it in our dreams alone, but even in our waking reveries, and in great efforts of invention, so great is the vivacity of our ideas, that we do not for a time distinguish them from the real presence of substantial objects; though the external organs of sense are open, and surrounded with their usual stimuli. Thus whilst I am thinking over the beautiful valley, through which I yesterday travelled, I do not perceive the furniture of my room: and there are some, whose waking imaginations are so apt to run into perfect reverie, that in their common attention to a favourite idea they do not hear the voice of the companion, who accosts them, unless it is repeated with unusual energy. This perpetual mistake in dreams and reveries, where our ideas of imagination are attended with a belief of the presence of external objects, evinces beyond a doubt, that all our ideas are repetitions of the motions of the nerves of sense, by which they were acquired; and that this belief is not, as some late philosophers contend, an instinct necessarily connected only with our perceptions. 7. A curious question demands our attention in this place; as we do not distinguish in our dreams and reveries between our perceptions of external objects, and our ideas of them in their absence, how do we distinguish them at any time? In a dream, if the sweetness of sugar occurs to my imagination, the whiteness and hardness of it, which were ideas usually connected with the sweetness, immediately follow in the train; and I believe a material lump of sugar present before my senses: but in my waking hours, if the sweetness occurs to my imagination, the stimulus of the table to my hand, or of the window to my eye, prevents the other ideas of the hardness and whiteness of the sugar from succeeding; and hence I perceive the fallacy, and disbelieve the existence of objects correspondent to those ideas, whose tribes or trains are broken by the stimulus of other objects. And further in our waking hours, we frequently exert our volition in comparing present appearances with such, as we have usually observed; and thus correct the errors of one sense by our general knowledge of nature by intuitive analogy. See Sect. XVII. 3. 7. Whereas in dreams the power of volition is suspended, we can recollect and compare our present ideas with none of our acquired knowledge, and are hence incapable of observing any absurdities in them. By this criterion we distinguish our waking from our sleeping hours, we can voluntarily recollect our sleeping ideas, when we are awake, and compare them with our waking ones; but we cannot in our sleep _voluntarily_ recollect our waking ideas at all. 8. The vast variety of scenery, novelty of combination, and distinctness of imagery, are other curious circumstances of our sleeping imaginations. The variety of scenery seems to arise from the superior activity and excellence of our sense of vision; which in an instant unfolds to the mind extensive fields of pleasurable ideas; while the other senses collect their objects slowly, and with little combination; add to this, that the ideas, which this organ presents us with, are more frequently connected with our sensation than those of any other. 9. The great novelty of combination is owing to another circumstance; the trains of ideas, which are carried on in our waking thoughts, are in our dreams dissevered in a thousand places by the suspension of volition, and the absence of irritative ideas, and are hence perpetually falling into new catenations. As explained in Sect. XVII. 1. 9. For the power of volition is perpetually exerted during our waking hours in comparing our passing trains of ideas with our acquired knowledge of nature, and thus forms many intermediate links in their catenation. And the irritative ideas excited by the stimulus of the objects, with which we are surrounded, are every moment intruded upon us, and form other links of our unceasing catenations of ideas. 10. The absence of the stimuli of external bodies, and of volition, in our dreams renders the organs of sense liable to be more strongly affected by the powers of sensation, and of association. For our desires or aversions, or the obtrusions of surrounding bodies, dissever the sensitive and associate tribes of ideas in our waking hours by introducing those of irritation and volition amongst them. Hence proceeds the superior distinctness of pleasurable or painful imagery in our sleep; for we recal the figure and the features of a long lost friend, whom we loved, in our dreams with much more accuracy and vivacity than in our waking thoughts. This circumstance contributes to prove, that our ideas of imagination are reiterations of those motions of our organs of sense, which were excited by external objects; because while we are exposed to the stimuli of present objects, our ideas of absent objects cannot be so distinctly formed. 11. The rapidity of the succession of transactions in our dreams is almost inconceivable; insomuch that, when we are accidentally awakened by the jarring of a door, which is opened into our bed-chamber, we sometimes dream a whole history of thieves or fire in the very instant of awaking. During the suspension of volition we cannot compare our other ideas with those of the parts of time in which they exist; that is, we cannot compare the imaginary scene, which is before us, with those changes of it, which precede or follow it: because this act of comparing requires recollection or voluntary exertion. Whereas in our waking hours, we are perpetually making this comparison, and by that means our waking ideas are kept confident with each other by intuitive analogy; but this companion retards the succession of them, by occasioning their repetition. Add to this, that the transactions of our dreams consist chiefly of visible ideas, and that a whole history of thieves and fire may be _beheld_ in an instant of time like the figures in a picture. 12. From this incapacity of attending to the parts of time in our dreams, arises our ignorance of the length of the night; which, but from our constant experience to the contrary, we should conclude was but a few minutes, when our sleep is perfect. The same happens in our reveries; thus when we are possessed with vehement joy, grief, or anger, time appears short, for we exert no volition to compare the present scenery with the past or future; but when we are compelled to perform those exercises of mind or body, which, are unmixed with passion, as in travelling over a dreary country, time appears long; for our desire to finish our journey occasions us more frequently to compare our present situation with the parts of time or place, which are before and behind us. So when we are enveloped in deep contemplation of any kind, or in reverie, as in reading a very interesting play or romance, we measure time very inaccurately; and hence, if a play greatly affects our passions, the absurdities of passing over many days or years, and or perpetual changes of place, are not perceived by the audience; as is experienced by every one, who reads or sees some plays of the immortal Shakespear; but it is necessary for inferior authors to observe those rules of the [Greek: pithanon] and [Greek: prepon] inculcated by Aristotle, because their works do not interest the passions sufficiently to produce complete reverie. Those works, however, whether a romance or a sermon, which do not interest us so much as to induce reverie, may nevertheless incline us to sleep. For those pleasurable ideas, which are presented to us, and are too gentle to excite laughter, (which is attended with interrupted voluntary exertions, as explained Sect. XXXIV. 1. 4.) and which are not accompanied with any other emotion, which usually excites some voluntary exertion, as anger, or fear, are liable to produce sleep; which consists in a suspension of all voluntary power. But if the ideas thus presented to us, and interest our attention, are accompanied with so much pleasurable or painful sensation as to excite our voluntary exertion at the same time, reverie is the consequence. Hence an interesting play produces reverie, a tedious one produces sleep: in the latter we become exhausted by attention, and are not excited to any voluntary exertion, and therefore sleep; in the former we are excited by some emotion, which prevents by its pain the suspension of volition, and in as much as it interests us, induces reverie, as explained in the next Section. But when our sleep is imperfect, as when we have determined to rise in half an hour, time appears longer to us than in most other situations. Here our solicitude not to oversleep the determined time induces us in this imperfect sleep to compare the quick changes of imagined scenery with the parts of time or place, they would have taken up, had they real exigence; and that more frequently than in our waking hours; and hence the time appears longer to us: and I make no doubt, but the permitted time appears long to a man going to the gallows, as the fear of its quick lapse will make him think frequently about it. 13. As we gain our knowledge of time by comparing the present scenery with the past and future, and of place by comparing the situations of objects with each other; so we gain our idea of consciousness by comparing ourselves with the scenery around us; and of identity by comparing our present consciousness with our past consciousness: as we never think of time or place, but when we make the companions above mentioned, so we never think of consciousness, but when we compare our own existence with that of other objects; nor of identity, but when we compare our present and our past consciousness. Hence the consciousness of our own existence, and of our identity, is owing to a voluntary exertion of our minds: and on that account in our complete dreams we neither measure time, are surprised at the sudden changes of place, nor attend to our own existence, or identity; because our power of volition is suspended. But all these circumstances are more or less observable in our incomplete ones; for then we attend a little to the lapse of time, and the changes of place, and to our own existence; and even to our identity of person; for a lady seldom dreams, that she is a soldier; nor a man, that he is brought to bed. 14. As long as our sensations only excite their sensual motions, or ideas, our sleep continues sound; but as soon as they excite desires or aversions, our sleep becomes imperfect; and when that desire or aversion is so strong, as to produce voluntary motions, we begin to awake; the larger muscles of the body are brought into action to remove that irritation or sensation, which a continued posture has caused; we stretch our limbs, and yawn, and our sleep is thus broken by the accumulation of voluntary power. Sometimes it happens, that the act of waking is suddenly produced, and this soon after the commencement of sleep; which is occasioned by some sensation so disagreeable, as instantaneously to excite the power of volition; and a temporary action of all the voluntary motions suddenly succeeds, and we start awake. This is sometimes accompanied with loud noise in the ears, and with some degree of fear; and when it is in great excess, so as to produce continued convulsive motions of those muscles, which are generally subservient to volition, it becomes epilepsy: the fits of which in some patients generally commence during sleep. This differs from the night-mare described in No. 3. of this Section, because in that the disagreeable sensation is not so great as to excite the power of volition into action; for as soon as that happens, the disease ceases. Another circumstance, which sometimes awakes people soon after the commencement of their sleep, is where the voluntary power is already so great in quantity as almost to prevent them from falling asleep, and then a little accumulation of it soon again awakens them; this happens in cases of insanity, or where the mind has been lately much agitated by fear or anger. There is another circumstance in which sleep is likewise of short duration, which arises from great debility, as after great over-fatigue, and in some fevers, where the strength of the patient is greatly diminished, as in these cases the pulse intermits or flutters, and the respiration is previously affected, it seems to originate from the want of some voluntary efforts to facilitate respiration, as when we are awake. And is further treated of in Vol. II. Class I. 2. 1. 2. on the Diseases of the Voluntary Power. Art. Somnus interruptus. 15. We come now to those motions which depend on irritation. The motions of the arterial and glandular systems continue in our sleep, proceeding slower indeed, but stronger and more uniformly, than in our waking hours, when they are incommoded by external stimuli, or by the movements of volition; the motions of the muscles subservient to respiration continue to be stimulated into action, and the other internal senses of hunger, thirst, and lust, are not only occasionally excited in our sleep, but their irritative motions are succeeded by their usual sensations, and make a part of the farrago of our dreams. These sensations of the want of air, of hunger, thirst, and lust, in our dreams, contribute to prove, that the nerves of the external senses are also alive and excitable in our sleep; but as the stimuli of external objects are either excluded from them by the darkness and silence of the night, or their access to them is prevented by the suspension of volition, these nerves of sense fall more readily into their connexions with sensation and with association; because much sensorial power, which during the day was expended in moving the external organs of sense in consequence of irritation from external stimuli, or in consequence of volition, becomes now in some degree accumulated, and renders the internal or immediate organs of sense more easily excitable by the other sensorial powers. Thus in respect to the eye, the irritation from external stimuli, and the power of volition during our waking hours, elevate the eye-lids, adapt the aperture of the iris to the quantity of light, the focus of the crystalline humour, and the angle of the optic axises to the distance of the object, all which perpetual activity during the day expends much sensorial power, which is saved during our sleep. Hence it appears, that not only those parts of the system, which are always excited by internal stimuli, as the stomach, intestinal canal, bile-ducts, and the various glands, but the organs of sense also may be more violently excited into action by the irritation from internal stimuli, or by sensation, during our sleep than in our waking hours; because during the suspension of volition, there is a greater quantity of the spirit of animation to be expended by the other sensorial powers. On this account our irritability to internal stimuli, and our sensibility to pain or pleasure, is not only greater in sleep, but increases as our sleep is prolonged. Whence digestion and secretion are performed better in sleep, than in our waking hours, and our dreams in the morning have greater variety and vivacity, as our sensibility increases, than at night when we first lie down. And hence epileptic fits, which are always occasioned by some disagreeable sensation, so frequently attack those, who are subject to them, in their sleep; because at this time the system is more excitable by painful sensation in consequence of internal stimuli; and the power of volition is then suddenly exerted to relieve this pain, as explained Sect. XXXIV. 1. 4. There is a disease, which frequently affects children in the cradle, which is termed ecstasy, and seems to consist in certain exertions to relieve painful sensation, in which the voluntary power is not so far excited as totally to awaken them, and yet is sufficient to remove the disagreeable sensation, which excites it; in this case changing the posture of the child frequently relieves it. I have at this time under my care an elegant young man about twenty-two years of age, who seldom sleeps more than an hour without experiencing a convulsion fit; which ceases in about half a minute without any subsequent stupor. Large doses of opium only prevented the paroxysms, so long as they prevented him from sleeping by the intoxication, which they induced. Other medicines had no effect on him. He was gently awakened every half hour for one night, but without good effect, as he soon slept again, and the fit returned at about the same periods of time, for the accumulated sensorial power, which occasioned the increased sensibility to pain, was not thus exhausted. This case evinces, that the sensibility of the system to internal excitation increases, as our sleep is prolonged; till the pain thus occasioned produces voluntary exertion; which, when it is in its usual degree, only awakens us; but when it is more violent, it occasions convulsions. The cramp in the calf of the leg is another kind of convulsion, which generally commences in sleep, occasioned by the continual increase of irritability from internal stimuli, or of sensibility, during that state of our existence. The cramp is a violent exertion to relieve pain, generally either of the skin from cold, or of the bowels, as in some diarrhoeas, or from the muscles having been previously overstretched, as in walking up or down steep hills. But in these convulsions of the muscles, which form the calf of the leg, the contraction is so violent as to occasion another pain in consequence of their own too violent contraction; as soon as the original pain, which caused the contraction, is removed. And hence the cramp, or spasm, of these muscles is continued without intermission by this new pain, unlike the alternate convulsions and remissions in epileptic fits. The reason, that the contraction of these muscles of the calf of the leg is more violent during their convulsion than that of others, depends on the weakness of their antagonist muscles; for after these have been contracted in their usual action, as at every step in walking, they are again extended, not, as most other muscles are, by their antagonists, but by the weight of the whole body on the balls of the toes; and that weight applied to great mechanical advantage on the heel, that is, on the other end of the bone of the foot, which thus acts as a lever. Another disease, the periods of which generally commence during our sleep, is the asthma. Whatever may be the remote cause of paroxysms of asthma, the immediate cause of the convulsive respiration, whether in the common asthma, or in what is termed the convulsive asthma, which are perhaps only different degrees of the same disease, must be owing to violent voluntary exertions to relieve pain, as in other convulsions; and the increase of irritability to internal stimuli, or of sensibility, during sleep must occasion them to commence at this time. Debilitated people, who have been unfortunately accustomed to great ingurgitation of spirituous potation, frequently part with a great quantity of water during the night, but with not more than usual in the day-time. This is owing to a beginning torpor of the absorbent system, and precedes anasarca, which commences in the day, but is cured in the night by the increase of the irritability of the absorbent system during sleep, which thus imbibes from the cellular membrane the fluids, which had been accumulated there during the day; though it is possible the horizontal position of the body may contribute something to this purpose, and also the greater irritability of some branches of the absorbent vessels, which open their mouths in the cells of the cellular membrane, than that of other branches. As soon as a person begins to sleep, the irritability and sensibility of the system begins to increase, owing to the suspension of volition and the exclusion of external stimuli. Hence the actions of the vessels in obedience to internal stimulation become stronger and more energetic, though less frequent in respect to number. And as many of the secretions are increased, so the heat of the system is gradually increased, and the extremities of feeble people, which had been cold during the day, become warm. Till towards morning many people become so warm, as to find it necessary to throw off some of their bed-clothes, as soon as they awake; and in others sweats are so liable to occur towards morning during their sleep. Thus those, who are not accustomed to sleep in the open air, are very liable to take cold, if they happen to fall asleep on a garden bench, or in a carriage with the window open. For as the system is warmer during sleep, as above explained, if a current of cold air affects any part of the body, a torpor of that part is more effectually produced, as when a cold blast of air through a key-hole or casement falls upon a person in a warm room. In those cases the affected part possesses less irritability in respect to heat, from its having previously been exposed to a greater stimulus of heat, as in the warm room, or during sleep; and hence, when the stimulus of heat is diminished, a torpor is liable to ensue; that is, we take cold. Hence people who sleep in the open air, generally feel chilly both at the approach of sleep, and on their awaking; and hence many people are perpetually subject to catarrhs if they sleep in a less warm head-dress, than that which they wear in the day. 16. Not only the sensorial powers of irritation and of sensation, but that of association also appear to act with greater vigour during the suspension of volition in sleep. It will be shewn in another place, that the gout generally first attacks the liver, and that afterwards an inflammation of the ball of the great toe commences by association, and that of the liver ceases. Now as this change or metastasis of the activity of the system generally commences in sleep, it follows, that these associations of motion exist with greater energy at that time; that is, that the sensorial faculty of association, like those of irritation and of sensation, becomes in some measure accumulated during the suspension of volition. Other associate tribes and trains of motions, as well as the irritative and sensitive ones, appear to be increased in their activity during the suspension of volition in sleep. As those which contribute to circulate the blood, and to perform the various secretions; as well as the associate tribes and trains of ideas, which contribute to furnish the perpetual dreams of our dreaming imaginations. In sleep the secretions have generally been supposed to be diminished, as the expectorated mucus in coughs, the fluids discharged in diarrhoeas, and in salivation, except indeed the secretion of sweat, which is often visibly increased. This error seems to have arisen from attention to the excretions rather than to the secretions. For the secretions, except that of sweat, are generally received into reservoirs, as the urine into the bladder, and the mucus of the intestines and lungs into their respective cavities; but these reservoirs do not exclude these fluids immediately by their stimulus, but require at the same time some voluntary efforts, and therefore permit them to remain during sleep. And as they thus continue longer in those receptacles in our sleeping hours, a greater part is absorbed from them, and the remainder becomes thicker, and sometimes in less quantity, though at the time it was secreted the fluid was in greater quantity than in our waking hours. Thus the urine is higher coloured after long sleep; which shews that a greater quantity has been secreted, and that more of the aqueous and saline part has been reabsorbed, and the earthy part left in the bladder; hence thick urine in fevers shews only a greater action of the vessels which secrete it in the kidneys, and of those which absorb it from the bladder. The same happens to the mucus expectorated in coughs, which is thus thickened by absorption of its aqueous and saline parts; and the same of the feces of the intestines. From hence it appears, and from what has been said in No. 15. of this Section concerning the increase of irritability and of sensibility during sleep, that the secretions are in general rather increased than diminished during these hours of our existence; and it is probable that nutrition is almost entirely performed in sleep; and that young animals grow more at this time than in their waking hours, as young plants have long since been observed to grow more in the night, which is their time of sleep. 17. Two other remarkable circumstances of our dreaming ideas are their inconsistency, and the total absence of surprise. Thus we seem to be present at more extraordinary metamorphoses of animals or trees, than are to be met with in the fables of antiquity; and appear to be transported from place to place, which seas divide, as quickly as the changes of scenery are performed in a play-house; and yet are not sensible of their inconsistency, nor in the least degree affected with surprise. We must consider this circumstance more minutely. In our waking trains of ideas, those that are inconsistent with the usual order of nature, so rarely have occurred to us, that their connexion is the slightest of all others: hence, when a consistent train of ideas is exhausted, we attend to the external stimuli, that usually surround us, rather than to any inconsistent idea, which might otherwise present itself; and if an inconsistent idea should intrude itself, we immediately compare it with the preceding one, and voluntarily reject the train it would introduce; this appears further in the Section on Reverie, in which state of the mind external stimuli are not attended to, and yet the streams of ideas are kept consistent by the efforts of volition. But as our faculty of volition is suspended, and all external stimuli are excluded in sleep, this slighter connexion of ideas takes place; and the train is said to be inconsistent; that is, dissimilar to the usual order of nature. But, when any consistent train of sensitive or voluntary ideas is flowing along, if any external stimulus affects us so violently, as to intrude irritative ideas forcibly into the mind, it disunites the former train of ideas, and we are affected with surprise. These stimuli of unusual energy or novelty not only disunite our common trains of ideas, but the trains of muscular motions also, which have not been long established by habit, and disturb those that have. Some people become motionless by great surprise, the fits of hiccup and or ague have been often removed by it, and it even affects the movements of the heart, and arteries; but in our sleep, all external stimuli are excluded, and in consequence no surprise can exist. See Section XVII. 3. 7. 18. We frequently awake with pleasure from a dream, which has delighted us, without being able to recollect the transactions of it; unless perhaps at a distance of time, some analogous idea may introduce afresh this forgotten train: and in our waking reveries we sometimes in a moment lose the train of thought, but continue to feel the glow of pleasure, or the depression of spirits, it occasioned: whilst at other times we can retrace with ease these histories of our reveries and dreams. The above explanation of surprise throws light upon this subject. When we are suddenly awaked by any violent stimulus, the surprise totally disunites the trains of our sleeping ideas from these of our waking ones; but if we gradually awake, this does not happen; and we readily unravel the preceding trains of imagination. 19. There are various degrees of surprise; the more intent we are upon the train of ideas, which we are employed about, the more violent must be the stimulus that interrupts them, and the greater is the degree of surprise. I have observed dogs, who have slept by the fire, and by their obscure barking and struggling have appeared very intent on their prey, that shewed great surprise for a few seconds after their awaking by looking eagerly around them; which they did not do at other times of waking. And an intelligent friend of mine has remarked, that his lady, who frequently speaks much and articulately in her sleep, could never recollect her dreams in the morning, when this happened to her: but that when she did not speak in her sleep, she could always recollect them. Hence, when our sensations act so strongly in sleep as to influence the larger muscles, as in those, who talk or struggle in their dreams; or in those, who are affected with complete reverie (as described in the next Section), great surprise is produced, when they awake; and these as well as those, who are completely drunk or delirious, totally forget afterwards their imaginations at those times. 20. As the immediate cause of sleep consists in the suspension of volition, it follows, that whatever diminishes the general quantity of sensorial power, or derives it from the faculty of volition, will constitute a remote cause of sleep; such as fatigue from muscular or mental exertion, which diminishes the general quantity of sensorial power; or an increase of the sensitive motions, as by attending to soft music, which diverts the sensorial power from the faculty of volition; or lastly, by increase of the irritative motions, as by wine, or food; or warmth; which not only by their expenditure of sensorial power diminish the quantity of volition; but also by their producing pleasureable sensations (which occasion other muscular or sensual motions in consequence), doubly decrease the voluntary power, and thus more forcibly produce sleep. See Sect. XXXIV. 1. 4. Another method of inducing sleep is delivered in a very ingenious work lately published by Dr. Beddoes. Who, after lamenting that opium frequently occasions restlessness, thinks, "that in most cases it would be better to induce sleep by the abstraction of stimuli, than by exhausting the excitability;" and adds, "upon this principle we could not have a better soporific than an atmosphere with a diminished proportion of oxygene air, and that common air might be admitted after the patient was asleep." (Observ. on Calculus, &c. by Dr. Beddoes, Murray.) If it should be found to be true, that the excitability of the system depends on the quantity of oxygene absorbed by the lungs in respiration according to the theory of Dr. Beddoes, and of M. Girtanner, this idea of sleeping in an atmosphere with less oxygene in its composition might be of great service in epileptic cases, and in cramp, and even in fits of the asthma, where their periods commence from the increase of irritability during sleep. Sleep is likewise said to be induced by mechanic pressure on the brain in the cases of spina bifida. Where there has been a defect of one of the vertebræ of the back, a tumour is protruded in consequence; and, whenever this tumour has been compressed by the hand, sleep is said to be induced, because the whole of the brain both within the head and spine becomes compressed by the retrocession of the fluid within the tumour. But by what means a compression of the brain induces sleep has not been explained, but probably by diminishing the secretion of sensorial power, and then the voluntary motions become suspended previously to the irritative ones, as occurs in most dying persons. Another way of procuring sleep mechanically was related to me by Mr. Brindley, the famous canal engineer, who was brought up to the business of a mill-wright; he told me, that he had more than once seen the experiment of a man extending himself across the large stone of a corn-mill, and that by gradually letting the stone whirl, the man fell asleep, before the stone had gained its full velocity, and he supposed would have died without pain by the continuance or increase of the motion. In this case the centrifugal motion of the head and feet must accumulate the blood in both those extremities of the body, and thus compress the brain. Lastly, we should mention the application of cold; which, when in a less degree, produces watchfulness by the pain it occasions, and the tremulous convulsions of the subcutaneous muscles; but when it is applied in great degree, is said to produce sleep. To explain this effect it has been said, that as the vessels of the skin and extremities become first torpid by the want of the stimulus of heat, and as thence less blood is circulated through them, as appears from their paleness, a greater quantity of blood poured upon the brain produces sleep by its compression of that organ. But I should rather imagine, that the sensorial power becomes exhausted by the convulsive actions in consequence of the pain of cold, and of the voluntary exercise previously used to prevent it, and that the sleep is only the beginning to die, as the suspension of voluntary power in lingering deaths precedes for many hours the extinction of the irritative motions. 21. The following are the characteristic circumstances attending perfect sleep. 1. The power of volition is totally suspended. 2. The trains of ideas caused by sensation proceed with greater facility and vivacity; but become inconsistent with the usual order of nature. The muscular motions caused by sensation continue; as those concerned in our evacuations during infancy, and afterwards in digestion, and in priapismus. 3. The irritative muscular motions continue, as those concerned in the circulation, in secretion, in respiration. But the irritative sensual motions, or ideas, are not excited; as the immediate organs of sense are not stimulated into action by external objects, which are excluded by the external organs of sense; which are not in sleep adapted to their reception by the power of volition, as in our waking hours. 4. The associate motions continue; but their first link is not excited into action by volition, or by external stimuli. In all respects, except those above mentioned, the three last sensorial powers are somewhat increased in energy during the suspension of volition, owing to the consequent accumulation of the spirit of animation. * * * * * SECT. XIX. OF REVERIE. 1. _Various degrees of reverie._ 2. _Sleep-walkers. Case of a young lady. Great surprise at awaking. And total forgetfulness of what passed in reverie._ 3. _No suspension of volition in reverie._ 4. _Sensitive motions continue, and are consistent._ 5. _Irritative motions continue, but are not succeeded by sensation._ 6. _Volition necessary for the perception of feeble impressions._ 7. _Associated motions continue._ 8. _Nerves of sense are irritable in sleep, but not in reverie._ 9. _Somnambuli are not asleep. Contagion received but once._ 10. _Definition of reverie._ 1. When we are employed with great sensation of pleasure, or with great efforts of volition, in the pursuit of some interesting train of ideas, we cease to be conscious of our existence, are inattentive to time and place, and do not distinguish this train of sensitive and voluntary ideas from the irritative ones excited by the presence of external objects, though our organs of sense are furnished with their accustomed stimuli, till at length this interesting train of ideas becomes exhausted, or the appulses of external objects are applied with unusual violence, and we return with surprise, or with regret, into the common track of life. This is termed reverie or studium. In some constitutions these reveries continue a considerable time, and are not to be removed without greater difficulty, but are experienced in a less degree by us all; when we attend earnestly to the ideas excited by volition or sensation, with their associated connexions, but are at the same time conscious at intervals of the stimuli of surrounding bodies. Thus in being present at a play, or in reading a romance, some persons are so totally absorbed as to forget their usual time of sleep, and to neglect their meals; while others are said to have been so involved in voluntary study as not to have heard the discharge of artillery; and there is a story of an Italian politician, who could think so intensely on other subjects, as to be insensible to the torture of the rack. From hence it appears, that these catenations of ideas and muscular motions, which form the trains of reverie, are composed both of voluntary and sensitive associations of them; and that these ideas differ from those of delirium or of sleep, as they are kept consistent by the power of volition; and they differ also from the trains of ideas belonging to insanity, as they are as frequently excited by sensation as by volition. But lastly, that the whole sensorial power is so employed on these trains of complete reverie, that like the violent efforts of volition, as in convulsions or insanity; or like the great activity of the irritative motions in drunkenness; or of the sensitive motions in delirium; they preclude all sensation consequent to external stimulus. 2. Those persons, who are said to walk in their sleep, are affected with reverie to so great a degree, that it becomes a formidable disease; the essence of which consists in the inaptitude of the mind to attend to external stimuli. Many histories of this disease have been published by medical writers; of which there is a very curious one in the Lausanne Transactions. I shall here subjoin an account of such a case, with its cure, for the better illustration of this subject. A very ingenious and elegant young lady, with light eyes and hair, about the age of seventeen, in other respects well, was suddenly seized soon after her usual menstruation with this very wonderful malady. The disease began with vehement convulsions of almost every muscle of her body, with great but vain efforts to vomit, and the most violent hiccoughs, that can be conceived: these were succeeded in about an hour with a fixed spasm; in which one hand was applied to her head, and the other to support it: in about half an hour these ceased, and the reverie began suddenly, and was at first manifest by the look of her eyes and countenance, which seemed to express attention. Then she conversed aloud with imaginary persons with her eyes open, and could not for about an hour be brought to attend to the stimulus of external objects by any kind of violence, which it was proper to use; these symptoms returned in this order every day for five or six weeks. These conversations were quite consistent, and we could understand, what she supposed her imaginary companions to answer, by the continuation of her part of the discourse. Sometimes she was angry, at other times shewed much wit and vivacity, but was most frequently inclined to melancholy. In these reveries she sometimes sung over some music with accuracy, and repeated whole pages from the English poets. In repeating some lines from Mr. Pope's works she had forgot one word, and began again, endeavouring to recollect it; when she came to the forgotten word, it was shouted aloud in her ear, and this repeatedly, to no purpose; but by many trials she at length regained it herself. These paroxysms were terminated with the appearance of inexpressible surprise, and great fear, from which she was some minutes in recovering herself, calling on her sister with great agitation, and very frequently underwent a repetition of convulsions, apparently from the pain of fear. See Sect. XVII. 3. 7. After having thus returned for about an hour every day for two or three weeks, the reveries seemed to become less complete, and some of their circumstances varied; so that she could walk about the room in them without running against any of the furniture; though these motions were at first very unsteady and tottering. And afterwards she once drank a dish of tea, when the whole apparatus of the tea-table was set before her; and expressed some suspicion, that a medicine was put into it, and once seemed to smell of a tuberose, which was in flower in her chamber, and deliberated aloud about breaking it from the stem, saying, "it would make her sister so charmingly angry." At another time in her melancholy moments she heard the sound of a passing bell, "I wish I was dead," she cried, listening to the bell, and then taking off one of her shoes, as she sat upon the bed, "I love the colour black," says she, "a little wider, and a little longer, even this might make me a coffin!"--Yet it is evident, she was not sensible at this time, any more than formerly, of seeing or hearing any person about her; indeed when great light was thrown upon her by opening the shutters of the window, her trains of ideas seemed less melancholy; and when I have forcibly held her hands, or covered her eyes, she appeared to grow impatient, and would say, she could not tell what to do, for she could neither see nor move. In all these circumstances her pulse continued unaffected as in health. And when the paroxysm was over, she could never recollect a single idea of what had passed in it. This astonishing disease, after the use of many other medicines and applications in vain, was cured by very large doses of opium given about an hour before the expected returns of the paroxysms; and after a few relapses, at the intervals of three or four months, entirely disappeared. But she continued at times to have other symptoms of epilepsy. 3. We shall only here consider, what happened during the time of her reveries, as that is our present subject; the fits of convulsion belong to another part of this treatise. Sect. XXXIV. 1. 4. There seems to have been no suspension of volition during the fits of reverie, because she endeavoured to regain the lost idea in repeating the lines of poetry, and deliberated about breaking the tuberose, and suspected the tea to have been medicated. 4. The ideas and muscular movements depending on sensation were exerted with their usual vivacity, and were kept from being inconsistent by the power of volition, as appeared from her whole conversation, and was explained in Sect. XVII. 3. 7. and XVIII. 16. 5. The ideas and motions dependant on irritation during the first weeks of her disease, whilst the reverie was complete, were never succeeded by the sensation of pleasure or pain; as she neither saw, heard, nor felt any of the surrounding objects. Nor was it certain that any irritative motions succeeded the stimulus of external objects, till the reverie became less complete, and then she could walk about the room without running against the furniture of it. Afterwards, when the reverie became still less complete from the use of opium, some few irritations were at times succeeded by her attention to them. As when she smelt at a tuberose, and drank a dish of tea, but this only when she seemed voluntarily to attend to them. 6. In common life when we listen to distant sounds, or wish to distinguish objects in the night, we are obliged strongly to exert our volition to dispose the organs of sense to perceive them, and to suppress the other trains of ideas, which might interrupt these feeble sensations. Hence in the present history the strongest stimuli were not perceived, except when the faculty of volition was exerted on the organ of sense; and then even common stimuli were sometimes perceived: for her mind was so strenuously employed in pursuing its own trains of voluntary or sensitive ideas, that no common stimuli could so far excite her attention as to disunite them; that is, the quantity of volition or of sensation already existing was greater than any, which could be produced in consequence of common degrees of stimulation. But the few stimuli of the tuberose, and of the tea, which she did perceive, were such, as accidentally coincided with the trains of thought, which were passing in her mind; and hence did not disunite those trains, and create surprise. And their being perceived at all was owing to the power of volition preceding or coinciding with that of irritation. This explication is countenanced by a fact mentioned concerning a somnambulist in the Lausanne Transactions, who sometimes opened his eyes for a short time to examine, where he was, or where his ink-pot stood, and then shut them again, dipping his pen into the pot every now and then, and writing on, but never opening his eyes afterwards, although he wrote on from line to line regularly, and corrected some errors of the pen, or in spelling: so much easier was it to him to refer to his ideas of the positions of things, than to his perceptions of them. 7. The associated motions persisted in their usual channel, as appeared by the combinations of her ideas, and the use of her muscles, and the equality of her pulse; for the natural motions of the arterial system, though originally excited like other motions by stimulus, seem in part to continue by their association with each other. As the heart of a viper pulsates long after it is cut out of the body, and removed from the stimulus of the blood. 8. In the section on sleep, it was observed that the nerves of sense are equally alive and susceptible to irritation in that state, as when we are awake; but that they are secluded from stimulating objects, or rendered unfit to receive them: but in complete reverie the reverse happens, the immediate organs of sense are exposed to their usual stimuli; but are either not excited into action at all, or not into so great action, as to produce attention or sensation. The total forgetfulness of what passes in reveries; and the surprise on recovering from them, are explained in Section XVIII. 19. and in Section XVII. 3. 7. 9. It appears from hence, that reverie is a disease of the epileptic or cataleptic kind, since the paroxysms of this young lady always began and frequently terminated with convulsions; and though in its greatest degree it has been called somnambulation, or sleep-walking, it is totally different from sleep; because the essential character of sleep consists in the total suspension of volition, which in reverie is not affected; and the essential character of reverie consists not in the absence of those irritative motions of our senses, which are occasioned by the stimulus of external objects, but in their never being productive of sensation. So that during a fit of reverie that strange event happens to the whole system of nerves, which occurs only to some particular branches of them in those, who are a second time exposed to the action of contagious matter. If the matter of the small-pox be inserted into the arm of one, who has previously had that disease, it will stimulate the wound, but the general sensation or inflammation of the system does not follow, which constitutes the disease. See Sect. XII. 3. 6. XXXIII. 2. 8. 10. The following is the definition or character of complete reverie. 1. The irritative motions occasioned by internal stimuli continue, those from the stimuli of external objects are either not produced at all, or are never succeeded by sensation or attention, unless they are at the same time excited by volition. 2. The sensitive motions continue, and are kept consistent by the power of volition. 3. The voluntary motions continue undisturbed. 4. The associate motions continue undisturbed. Two other cases of reverie are related in Section XXXIV. 3. which further evince, that reverie is an effort of the mind to relieve some painful sensation, and is hence allied to convulsion, and to insanity. Another case is related in Class III. 1. 2. 2. * * * * * SECT. XX. OF VERTIGO. 1. _We determine our perpendicularity by the apparent motions of objects. A person hood-winked cannot walk in a straight line. Dizziness in looking from a tower, in a room stained with uniform lozenges, on riding over snow._ 2. _Dizziness from moving objects. A whirling-wheel. Fluctuations of a river. Experiment with a child._ 3. _Dizziness from our own motions and those of other objects._ 4. _Riding over a broad stream. Sea-sickness._ 5. _Of turning round on one foot. Dervises in Turkey. Attention of the mind prevents slight sea-sickness. After a voyage ideas of vibratory motions are still perceived on shore._ 6. _Ideas continue some time after they are excited. Circumstances of turning on one foot, standing on a tower, and walking in the dark, explained._ 7. _Irritative ideas of apparent motions. Irritative ideas of sounds. Battèment of the sound of bells and organ-pipes. Vertiginous noise in the head. Irritative motions of the stomach, intestines, and glands._ 8. _Symptoms that accompany vertigo. Why vomiting comes on in strokes of the palsy. By the motion of a ship. By injuries on the head. Why motion makes sick people vomit._ 9. _Why drunken people are vertiginous. Why a stone in the ureter, or bile-duct, produces vomiting._ 10. _Why after a voyage ideas of vibratory motions are perceived on shore._ 11. _Kinds of vertigo and their cure._ 12. _Definition of vertigo._ 1. In learning to walk we judge of the distances of the objects, which we approach, by the eye; and by observing their perpendicularity determine our own. This circumstance not having been attended to by the writers on vision, the disease called vertigo or dizziness has been little understood. When any person loses the power of muscular action, whether he is erect or in a sitting posture, he sinks down upon the ground; as is seen in fainting fits, and other instances of great debility. Hence it follows, that some exertion of muscular power is necessary to preserve our perpendicular attitude. This is performed by proportionally exerting the antagonist muscles of the trunk, neck, and limbs; and if at any time in our locomotions we find ourselves inclining to one side, we either restore our equilibrium by the efforts of the muscles on the other side, or by moving one of our feet extend the base, which we rest upon, to the new center of gravity. But the most easy and habitual manner of determining our want of perpendicularity, is by attending to the apparent motion of the objects within the sphere of distinct vision; for this apparent motion of objects, when we incline from our perpendicularity, or begin to fall, is as much greater than the real motion of the eye, as the diameter of the sphere of distinct vision is to our perpendicular height. Hence no one, who is hood-winked, can walk in a straight line for a hundred steps together; for he inclines so greatly, before he is warned of his want of perpendicularity by the sense of touch, not having the apparent motions of ambient objects to measure this inclination by, that he is necessitated to move one of his feet outwards, to the right or to the left, to support the new centre of gravity, and thus errs from the line he endeavours to proceed in. For the same reason many people become dizzy, when they look from the summit of a tower, which is raised much above all other objects, as these objects are out of the sphere of distinct vision, and they are obliged to balance their bodies by the less accurate feelings of their muscles. There is another curious phenomenon belonging to this place, if the circumjacent visible objects are so small, that we do not distinguish their minute parts; or so similar, that we do not know them from each other; we cannot determine our perpendicularity by them. Thus in a room hung with a paper, which is coloured over with similar small black lozenges or rhomboids, many people become dizzy; for when they begin to fall, the next and the next lozenge succeeds upon the eye; which they mistake for the first, and are not aware, that they have any apparent motion. But if you fix a sheet of paper, or draw any other figure, in the midst of these lozenges, the charm ceases, and no dizziness is perceptible.--The same occurs, when we ride over a plain covered with snow without trees or other eminent objects. 2. But after having compared visible objects at rest with the sense of touch, and learnt to distinguish their shapes and shades, and to measure our want of perpendicularity by their apparent motions, we come to consider them in real motion. Here a new difficulty occurs, and we require some experience to learn the peculiar mode of motion of any moving objects, before we can make use of them for the purposes of determining our perpendicularity. Thus some people become dizzy at the sight of a whirling wheel, or by gazing on the fluctuations of a river, if no steady objects are at the same time within the sphere of their distinct vision; and when a child first can stand erect upon his legs, if you gain his attention to a white handkerchief steadily extended like a sail, and afterwards make it undulate, he instantly loses his perpendicularity, and tumbles on the ground. 3. A second difficulty we have to encounter is to distinguish our own real movements from the apparent motions of objects. Our daily practice of walking and riding on horseback soon instructs us with accuracy to discern these modes of motion, and to ascribe the apparent motions of the ambient objects to ourselves; but those, which we have not acquired by repeated habit, continue to confound us. So as we ride on horseback the trees and cottages, which occur to us, appear at rest; we can measure their distances with our eye, and regulate our attitude by them; yet if we carelessly attend to distant hills or woods through a thin hedge, which is near us, we observe the jumping and progressive motions of them; as this is increased by the paralax of these objects; which we have not habituated ourselves to attend to. When first an European mounts an elephant sixteen feet high, and whose mode of motion he is not accustomed to, the objects seem to undulate, as he passes, and he frequently becomes sick and vertiginous, as I am well informed. Any other unusual movement of our bodies has the same effect, as riding backwards in a coach, swinging on a rope, turning round swiftly on one leg, scating on the ice, and a thousand others. So after a patient has been long confined to his bed, when he first attempts to walk, he finds himself vertiginous, and is obliged by practice to learn again the particular modes of the apparent motions of objects, as he walks by them. 4. A third difficulty, which occurs to us in learning to balance ourselves by the eye, is, when both ourselves and the circumjacent objects are in real motion. Here it is necessary, that we should be habituated to both these modes of motion in order to preserve our perpendicularity. Thus on horseback we accurately observe another person, whom we meet, trotting towards us, without confounding his jumping and progressive motion with our own, because we have been accustomed to them both; that is, to undergo the one, and to see the other at the same time. But in riding over a broad and fluctuating stream, though we are well experienced in the motions of our horse, we are liable to become dizzy from our inexperience in that of the water. And when first we go on ship-board, where the movements of ourselves, and the movements of the large waves are both new to us, the vertigo is almost unavoidable with the terrible sickness, which attends it. And this I have been assured has happened to several from being removed from a large ship into a small one; and again from a small one into a man of war. 5. From the foregoing examples it is evident, that, when we are surrounded with unusual motions, we lose our perpendicularity: but there are some peculiar circumstances attending this effect of moving objects, which we come now to mention, and shall hope from the recital of them to gain some insight into the manner of their production. When a child moves round quick upon one foot, the circumjacent objects become quite indistinct, as their distance increases their apparent motions; and this great velocity confounds both their forms, and their colours, as is seen in whirling round a many coloured wheel; he then loses his usual method of balancing himself by vision, and begins to stagger, and attempts to recover himself by his muscular feelings. This staggering adds to the instability of the visible objects by giving a vibratory motion besides their rotatory one. The child then drops upon the ground, and the neighbouring objects seem to continue for some seconds of time to circulate around him, and the earth under him appears to librate like a balance. In some seconds of time these sensations of a continuation of the motion of objects vanish; but if he continues turning round somewhat longer, before he falls, sickness and vomiting are very liable to succeed. But none of these circumstances affect those who have habituated themselves to this kind of motion, as the dervises in Turkey, amongst whom these swift gyrations are a ceremony of religion. In an open boat passing from Leith to Kinghorn in Scotland, a sudden change of the wind shook the undistended sail, and stopt our boat; from this unusual movement the passengers all vomited except myself. I observed, that the undulation of the ship, and the instability of all visible objects, inclined me strongly to be sick; and this continued or increased, when I closed my eyes, but as often as I bent my attention with energy on the management and mechanism of the ropes and sails, the sickness ceased; and recurred again, as often as I relaxed this attention; and I am assured by a gentleman of observation and veracity, that he has more than once observed, when the vessel has been in immediate danger, that the sea-sickness of the passengers has instantaneously ceased, and recurred again, when the danger was over. Those, who have been upon the water in a boat or ship so long, that they have acquired the necessary habits of motion upon that unstable element, at their return on land frequently think in their reveries, or between sleeping and waking, that they observe the room, they sit in, or some of its furniture, to librate like the motion of the vessel. This I have experienced myself, and have been told, that after long voyages, it is some time before these ideas entirely vanish. The same is observable in a less degree after having travelled some days in a stage coach, and particularly when we lie down in bed, and compose ourselves to sleep; in this case it is observable, that the rattling noise of the coach, as well as the undulatory motion, haunts us. The drunken vertigo, and the vulgar custom of rocking children, will be considered in the next Section. 6. The motions, which are produced by the power of volition, may be immediately stopped by the exertion of the same power on the antagonist muscles; otherwise these with all the other classes of motion continue to go on, some time after they are excited, as the palpitation of the heart continues after the object of fear, which occasioned it, is removed. But this circumstance is in no class of motions more remarkable than in those dependent on irritation; thus if any one looks at the sun, and then covers his eyes with his hand, he will for many seconds of time, perceive the image of the sun marked on his retina: a similar image of all other visible objects would remain some time formed on the retina, but is extinguished by the perpetual change of the motions of this nerve in our attention to other objects. To this must be added, that the longer time any movements have continued to be excited without fatigue to the organ, the longer will they continue spontaneously, after the excitement is withdrawn: as the taste of tobacco in the mouth after a person has been smoaking it. This taste remains so strong, that if a person continues to draw air through a tobacco pipe in the dark, after having been smoking some time, he cannot distinguish whether his pipe be lighted or not. From these two considerations it appears, that the dizziness felt in the head, after seeing objects in unusual motion, is no other than a continuation of the motions of the optic nerve excited by those objects and which engage our attention. Thus on turning round on one foot, the vertigo continues for some seconds of time after the person is fallen on the ground; and the longer he has continued to revolve, the longer will continue these successive motions of the parts of the optic nerve. _Additional Observations on _VERTIGO. After revolving with your eyes open till you become vertiginous, as soon as you cease to revolve, not only the circum-ambient objects appear to circulate round you in a direction contrary to that, in which you have been turning, but you are liable to roll your eyes forwards and backwards; as is well observed, and ingeniously demonstrated by Dr. Wells in a late publication on vision. The same occurs, if you revolve with your eyes closed, and open them immediately at the time of your ceasing to turn; and even during the whole time of revolving, as may be felt by your hand pressed lightly on your closed eyelids. To these movements of the eyes, of which he supposes the observer to be inconscious, Dr. Wells ascribes the apparent circumgyration of objects on ceasing to revolve. The cause of thus turning our eyes forwards, and then back again, after our body is at rest, depends, I imagine, on the same circumstance, which induces us to follow the indistinct spectra, which are formed on one side of the center of the retina, when we observe them apparently on clouds, as described in Sect. XL. 2. 2.; and then not being able to gain a more distinct vision of them, we turn our eyes back, and again and again pursue the flying shade. But this rolling of the eyes, after revolving till we become vertiginous, cannot cause the apparent circumgyration of objects, in a direction contrary to that in which we have been revolving, for the following reasons. 1. Because in pursuing a spectrum in the sky, or on the ground, as above mentioned, we perceive no retrograde motions of objects. 2. Because the apparent retrograde motions of objects, when we have revolved till we are vertiginous, continues much longer than the rolling of the eyes above described. 3. When we have revolved from right to left, the apparent motion of objects, when we stop, is from left to right; and when we have revolved from left to right, the apparent circulation of objects is from right to left; yet in both these cases the eyes of the revolver are seen equally to roll forwards and backwards. 4. Because this rolling of the eyes backwards and forwards takes place during our revolving, as may be perceived by the hand lightly pressed on the closed eyelids, and therefore exists before the effect ascribed to it. And fifthly, I now come to relate an experiment, in which the rolling of the eyes does not take place at all after revolving, and yet the vertigo is more distressing than in the situations above mentioned. If any one looks steadily at a spot in the ceiling over his head, or indeed at his own finger held up high over his head, and in that situation turns round till he becomes giddy; and then stops, and looks horizontally; he now finds, that the apparent rotation of objects is from above downwards, or from below upwards; that is, that the apparent circulation of objects is now vertical instead of horizontal, making part of a circle round the axis of his _eye_; and this without any rolling of his eyeballs. The reason of there being no rolling of the eyeballs, perceived after this experiment, is, because the images of objects are formed in rotation round the axis of the eye, and not from one side to the other of the axis of it; so that, as the eyeball has not power to turn in its socket round its own axis, it cannot follow the apparent motions of these evanescent spectra, either before or after the body is at rest. From all which arguments it is manifest, that these apparent retrograde gyrations of objects are not caused by the rolling of the eyeballs; first, because no apparent retrogression of objects is observed in other rollings of the eyes: secondly, because the apparent retrogression of objects continues many seconds after the rolling of the eyeballs ceases. Thirdly, because the apparent retrogression of objects is sometimes one way, and sometimes another, yet the rolling of the eyeballs is the same. Fourthly, because the rolling of the eyeballs exists before the apparent retrograde motions of objects is observed; that is, before the revolving person stops. And fifthly, because the apparent retrograde gyration of objects is produced, when there is no rolling of the eyeballs at all. Doctor Wells imagines, that no spectra can be gained in the eye, if a person revolves with his eyelids closed, and thinks this a sufficient argument against the opinion, that the apparent progression of the spectra of light or colours in the eye can cause the apparent retrogression of objects in the vertigo above described; but it is certain, when any person revolves in a light room with his eyes closed, that he nevertheless perceives differences of light both in quantity and colour through his eyelids, as he turns round; and readily gains spectra of those differences. And these spectra are not very different except in vivacity from those, which he acquires, when he revolves with unclosed eyes, since if he then revolves very rapidly the colours and forms of surrounding objects are as it were mixed together in his eye;. as when, the prismatic colours are painted on a wheel, they appear white as they revolve. The truth of this is evinced by the staggering or vertigo of men perfectly blind, when they turn round; which is not attended with apparent circulation of objects, but is a vertiginous disorder of the sense of touch. Blind men balance themselves by their sense of touch; which, being less adapted for perceiving small deviations from their perpendicular, occasions them to carry themselves more erect in walking. This method of balancing themselves by the direction of their pressure against the floor, becomes disordered by the unusual mode of action in turning round, and they begin to lose their perpendicularity, that is, they become vertiginous; but without any apparent circular motions of visible objects. It will appear from the following experiments, that the apparent progression of the ocular spectra of light or colours is the cause of the apparent retrogression of objects, after a person has revolved, till he is vertiginous. First, when a person turns round in a light room with his eyes open, but closes them before he stops, he will seem to be carried forwards in the direction he was turning for a short time after he stops. But if he opens his eyes again, the objects before him instantly appear to move in a retrograde direction, and he loses the sensation of being carried forwards. The same occurs if a person revolves in a light room with his eyes closed; when he stops, he seems to be for a time carried forwards, if his eyes are still closed; but the instant he opens them, the surrounding objects appear to move in retrograde gyration. From hence it may be concluded, that it is the sensation or imagination of our continuing to go forwards in the direction in which we were turning, that causes the apparent retrograde circulation of objects. Secondly, though there is an audible vertigo, as is known by the battement, or undulations of sound in the ears, which many vertiginous people experience; and though there is also a tangible vertigo, as when a blind person turns round, as mentioned above; yet as this circumgyration of objects is an hallucination or deception of the sense of sight, we are to look for the cause of our appearing to move forward, when we stop with our eyes closed after gyration, to some affection of this sense. Now, thirdly, if the spectra formed in the eye during our rotation, continue to change, when we stand still, like the spectra described in Sect. III. 3. 6. such changes must suggest to us the idea or sensation of our still continuing to turn round; as is the case, when we revolve in a light room, and close our eyes before we stop. And lastly, on opening our eyes in the situation above described, the objects we chance to view amid these changing spectra in the eye, must seem to move in a contrary direction; as the moon sometimes appears to move retrograde, when swift-gliding clouds are passing forwards so much nearer the eye of the beholder. To make observations on faint ocular spectra requires some degree of habit, and composure of mind, and even patience; some of those described in Sect. XL. were found difficult to see, by many, who tried them; now it happens, that the mind, during the confusion of vertigo, when all the other irritative tribes of motion, as well as those of vision, are in some degree disturbed, together with the fear of falling, is in a very unfit state for the contemplation of such weak sensations, as are occasioned by faint ocular spectra. Yet after frequently revolving, both with my eyes closed, and with them open, and attending to the spectra remaining in them, by shading the light from my eyelids more or less with my hand, I at length ceased to have the idea of going forward, after I stopped with my eyes closed; and saw changing spectra in my eyes, which seemed to move, as it were, over the field of vision; till at length, by repeated trials on sunny days, I persuaded myself, on opening my eyes, after revolving some time, on a shelf of gilded books in my library, that I could perceive the spectra in my eyes move forwards over one or two of the books, like the vapours in the air of a summer's day; and could so far undeceive myself, as to perceive the books to stand still. After more trials I sometimes brought myself to believe, that I saw changing spectra of lights and shades moving in my eyes, after turning round for some time, but did not imagine either the spectra or the objects to be in a state of gyration. I speak, however, with diffidence of these facts, as I could not always make the experiments succeed, when there was not a strong light in my room, or when my eyes were not in the most proper state for such observations. The ingenious and learned M. Sauvage has mentioned other theories to account for the apparent circumgyration of objects in vertiginous people. As the retrograde motions of the particles of blood in the optic arteries, by spasm, or by fear, as is seen in the tails of tadpoles, and membranes between the fingers of frogs. Another cause he thinks may be from the librations to one side, and to the other, of the crystalline lens in the eye, by means of involuntary actions of the muscles, which constitute the ciliary process. Both these theories lie under the same objection as that of Dr. Wells before mentioned; namely, that the apparent motions of objects, after the observer has revolved for some time, should appear to vibrate this way and that; and not to circulate uniformly in a direction contrary to that, in which the observer had revolved. M. Sauvage has, lastly, mentioned the theory of colours left in the eye, which he has termed impressions on the retina. He says, "Experience teaches us, that impressions made on the retina by a visible object remain some seconds after the object is removed; as appears from the circle of fire which we see, when a fire-stick is whirled round in the dark; therefore when we are carried round our own axis in a circle, we undergo a temporary vertigo, when we stop; because the impressions of the circumjacent objects remain for a time afterwards on the retina." Nosolog. Method. Clas. VIII. I. 1. We have before observed, that the changes of these colours remaining in the eye, evinces them to be motions of the fine terminations of the retina, and not impressions on it; as impressions on a passive substance must either remain, or cease intirely. See an additional note at the end of the second volume. Any one, who stands alone on the top of a high tower, if he has not been accustomed to balance himself by objects placed at such distances and with such inclinations, begins to stagger, and endeavours to recover himself by his muscular feelings. During this time the apparent motion of objects at a distance below him is very great, and the spectra of these apparent motions continue a little time after he has experienced them; and he is persuaded to incline the contrary way to counteract their effects; and either immediately falls, or applying his hands to the building, uses his muscular feelings to preserve his perpendicular attitude, contrary to the erroneous persuasions of his eyes. Whilst the person, who walks in the dark, staggers, but without dizziness; for he neither has the sensation of moving objects to take off his attention from his muscular feelings, nor has he the spectra of those motions continued on his retina to add to his confusion. It happens indeed sometimes to one landing on a tower, that the idea of his not having room to extend his base by moving one of his feet outwards, when he begins to incline, superadds fears to his other inconveniences; which like surprise, joy, or any great degree of sensation, enervates him in a moment, by employing the whole sensorial power, and by thus breaking all the associated trains and tribes of motion. 7. The irritative ideas of objects, whilst we are awake, are perpetually present to our sense of sight; as we view the furniture of our rooms, or the ground, we tread upon, throughout the whole day without attending to it. And as our bodies are never at perfect rest during our waking hours, these irritative ideas of objects are attended perpetually with irritative ideas of their apparent motions. The ideas of apparent motions are always irritative ideas, because we never attend to them, whether we attend to the objects themselves, or to their real motions, or to neither. Hence the ideas of the apparent motions of objects are a complete circle of irritative ideas, which continue throughout the day. Also during all our waking hours, there is a perpetual confused sound of various bodies, as of the wind in our rooms, the fire, distant conversations, mechanic business; this continued buzz, as we are seldom quite motionless, changes its loudness perpetually, like the sound of a bell; which rises and falls as long as it continues, and seems to pulsate on the ear. This any one may experience by turning himself round near a waterfall; or by striking a glass bell, and then moving the direction of its mouth towards the ears, or from them, as long as its vibrations continue. Hence this undulation of indistinct sound makes another concomitant circle of irritative ideas, which continues throughout the day. We hear this undulating sound, when we are perfectly at rest ourselves, from other sonorous bodies besides bells; as from two organ-pipes, which are nearly but not quite in unison, when they are sounded together. When a bell is struck, the circular form is changed into an eliptic one; the longest axis of which, as the vibrations continue, moves round the periphery of the bell; and when either axis of this elipse is pointed towards our ears, the sound is louder; and less when the intermediate parts of the elipse are opposite to us. The vibrations of the two organ-pipes may be compared to Nonius's rule; the sound is louder, when they coincide, and less at the intermediate times. But, as the sound of bells is the most familiar of those sounds, which have a considerable battement, the vertiginous patients, who attend to the irritative circles of sounds above described, generally compare it to the noise of bells. The peristaltic motions of our stomach and intestines, and the secretions of the various glands, are other circles of irritative motions, some of them more or less complete, according to our abstinence or satiety. So that the irritative ideas of the apparent motions of objects, the irritative battements of sounds, and the movements of our bowels and glands compose a great circle of irritative tribes of motion: and when one considerable part of this circle of motions becomes interrupted, the whole proceeds in confusion, as described in Section XVII. 1. 7. on Catenation of Motions. 8. Hence a violent vertigo, from whatever cause it happens, is generally attended with undulating noise in the head, perversions of the motions of the stomach and duodenum, unusual excretion of bile and gastric juice, with much pale urine, sometimes with yellowness of the skin, and a disordered secretion of almost every gland of the body, till at length the arterial system is affected, and fever succeeds. Thus bilious vomitings accompany the vertigo occasioned by the motion of a ship; and when the brain is rendered vertiginous by a paralytic affection of any part of the body, a vomiting generally ensues, and a great discharge of bile: and hence great injuries of the head from external violence are succeeded with bilious vomitings, and sometimes with abscesses of the liver. And hence, when a patient is inclined to vomit from other causes, as in some fevers, any motions of the attendants in his room, or of himself when he is raised or turned in his bed, presently induces the vomiting by superadding a degree of vertigo. 9. And conversely it is very usual with those, whose stomachs are affected from internal causes, to be afflicted with vertigo, and noise in the head; such is the vertigo of drunken people, which continues, when their eyes are closed, and themselves in a recumbent posture, as well as when they are in an erect posture, and have their eyes open. And thus the irritation of a stone in the bile-duct, or in the ureter, or an inflammation of any of the intestines, are accompanied with vomitings and vertigo. In these cases the irritative motions of the stomach, which are in general not attended to, become so changed by some unnatural stimulus, as to become uneasy, and excite our sensation or attention. And thus the other irritative trains of motions, which are associated with it, become disordered by their sympathy. The same happens, when a piece of gravel sticks in the ureter, or when some part of the intestinal canal becomes inflamed. In these cases the irritative muscular motions are first disturbed by unusual stimulus, and a disordered action of the sensual motions, or dizziness ensues. While in sea-sickness the irritative sensual motions, as vertigo, precedes; and the disordered irritative muscular motions, as those of the stomach in vomiting, follow. 10. When these irritative motions are disturbed, if the degree be not very great, the exertion of voluntary attention to any other object, or any sudden sensation, will disjoin these new habits of motion. Thus some drunken people have become sober immediately, when any accident has strongly excited their attention; and sea-sickness has vanished, when the ship has been in danger. Hence when our attention to other objects is most relaxed, as just before we fall asleep, or between our reveries when awake, these irritative ideas of motion and sound are most liable to be perceived; as those, who have been at sea, or have travelled long in a coach, seem to perceive the vibrations of the ship, or the rattling of the wheels, at these intervals; which cease again, as soon as they exert their attention. That is, at those intervals they attend to the apparent motions, and to the battement of sounds of the bodies around them, and for a moment mistake them for those real motions of the ship, and noise of wheels, which they had lately been accustomed to: or at these intervals of reverie, or on the approach of sleep, these supposed motions or sounds may be produced entirely by imagination. We may conclude from this account of vertigo, that sea-sickness is not an effort of nature to relieve herself, but a necessary consequence of the associations or catenations of animal motions. And may thence infer, that the vomiting, which attends the gravel in the ureter, inflammations of the bowels, and the commencement of some fevers, has a similar origin, and is not always an effort of the vis medicatrix naturæ. But where the action of the organ is the immediate consequence of the stimulating cause, it is frequently exerted to dislodge that stimulus, as in vomiting up an emetic drug; at other times, the action of an organ is a general effort to relieve pain, as in convulsions of the locomotive muscles; other actions drink up and carry on the fluids, as in absorption and secretion; all which may be termed efforts of nature to relieve, or to preserve herself. 11. The cure of vertigo will frequently depend on our previously investigating the cause of it, which from what has been delivered above may originate from the disorder of any part of the great tribes of irritative motions, and of the associate motions catenated with them. Many people, when they arrive at fifty or sixty years of age, are affected with slight vertigo; which is generally but wrongly ascribed to indigestion, but in reality arises from a beginning defect of their sight; as about this time they also find it necessary to begin to use spectacles, when they read small prints, especially in winter, or by candle light, but are yet able to read without them during the summer days, when the light is stronger. These people do not see objects so distinctly as formerly, and by exerting their eyes more than usual, they perceive the apparent motions of objects, and confound them with the real motions of them; and therefore cannot accurately balance themselves so as easily to preserve their perpendicularity by them. That is, the apparent motions of objects, which are at rest, as we move by them, should only excite irritative ideas: but as these are now become less distinct, owing to the beginning imperfection of our sight, we are induced _voluntarily_ to attend to them; and then these apparent motions become succeeded by sensation; and thus the other parts of the trains of irritative ideas, or irritative muscular motions, become disordered, as explained above. In these cases of slight vertigo I have always promised my patients, that they would get free from it in two or three months, as they should acquire the habit of balancing their bodies by less distinct objects, and have seldom been mistaken in my prognostic. There is an auditory vertigo, which is called a noise in the head, explained in No. 7. of this section, which also is very liable to affect people in the advance of life, and is owing to their hearing less perfectly than before. This is sometimes called a ringing, and sometimes a singing, or buzzing, in the ears, and is occasioned by our first experiencing a disagreeable sensation from our not being able distinctly to hear the sounds, we used formerly to hear distinctly. And this disagreeable sensation excites desire and consequent volition; and when we voluntarily attend to small indistinct sounds, even the whispering of the air in a room, and the pulsations of the arteries of the ear are succeeded by sensation; which minute sounds ought only to have produced irritative sensual motions, or unperceived ideas. See Section XVII. 3. 6. These patients after a while lose this auditory vertigo, by acquiring a new habit of not attending voluntarily to these indistinct sounds, but contenting themselves with the less accuracy of their sense of hearing. Another kind of vertigo begins with the disordered action of some irritative muscular motions, as those of the stomach from intoxication, or from emetics; or those of the ureter, from the stimulus of a stone lodged in it; and it is probable, that the disordered motions of some of the great congeries of glands, as of those which form the liver, or of the intestinal canal, may occasion vertigo in consequence of their motions being associated or catenated with the great circles of irritative motions; and from hence it appears, that the means of cure must be adapted to the cause. To prevent sea-sickness it is probable, that the habit of swinging for a week or two before going on shipboard might be of service. For the vertigo from failure of sight, spectacles may be used. For the auditory vertigo, æther may be dropt into the ear to stimulate the part, or to dissolve ear-wax, if such be a part of the cause. For the vertigo arising from indigestion, the peruvian bark and a blister are recommended. And for that owing to a stone in the ureter, venesection, cathartics, opiates, sal soda aerated. 12. Definition of vertigo. 1. Some of the irritative sensual, or muscular motions, which were usually not succeeded by sensation, are in this disease succeeded by sensation; and the trains or circles of motions, which were usually catenated with them, are interrupted, or inverted, or proceed in confusion. 2. The sensitive and voluntary motions continue undisturbed. 3. The associate trains or circles of motions continue; but their catenations with some of the irritative motions are disordered, or inverted, or dissevered. * * * * * SECT. XXI. OF DRUNKENNESS. 1. _Sleep from satiety of hunger. From rocking children. From uniform sounds._ 2. _Intoxication from common food after fatigue and inanition._ 3. _From wine or of opium. Chilness after meals. Vertigo. Why pleasure is produced by intoxication, and by swinging and rocking children. And why pain is relieved by it._ 4. _Why drunkards stagger and stammer, and are liable to weep._ 5. _And become delirious, sleepy, and stupid._ 6. _Or make pale urine and vomit._ 7. _Objects are seen double._ 8. _Attention of the mind diminishes drunkenness._ 9. _Disordered irritative motions of all the senses._ 10. _Diseases from drunkenness._ 11. _Definition of drunkenness._ 1. In the state of nature when the sense of hunger is appeased by the stimulus of agreeable food, the business of the day is over, and the human savage is at peace with the world, he then exerts little attention to external objects, pleasing reveries of imagination succeed, and at length sleep is the result: till the nourishment which he has procured, is carried over every part of the system to repair the injuries of action, and he awakens with fresh vigour, and feels a renewal of his sense of hunger. The juices of some bitter vegetables, as of the poppy and the laurocerasus, and the ardent spirit produced in the fermentation of the sugar found in vegetable juices, are so agreeable to the nerves of the stomach, that, taken in a small quantity, they instantly pacify the sense of hunger; and the inattention to external stimuli with the reveries of imagination, and sleep, succeeds, in the same manner as when the stomach is filled with other less intoxicating food. This inattention to the irritative motions occasioned by external stimuli is a very important circumstance in the approach of sleep, and is produced in young children by rocking their cradles: during which all visible objects become indistinct to them. An uniform soft repeated sound, as the murmurs of a gentle current, or of bees, are said to produce the same effect, by presenting indistinct ideas of inconsequential sounds, and by thus stealing our attention from other objects, whilst by their continued reiterations they become familiar themselves, and we cease gradually to attend to any thing, and sleep ensues. 2. After great fatigue or inanition, when the stomach is suddenly filled with flesh and vegetable food, the inattention to external stimuli, and the reveries of imagination, become so conspicuous as to amount to a degree of intoxication. The same is at any time produced by superadding a little wine or opium to our common meals; or by taking these separately in considerable quantity; and this more efficaciously after fatigue or inanition; because a less quantity of any stimulating material will excite an organ into energetic action, after it has lately been torpid from defect of stimulus; as objects appear more luminous, after we have been in the dark; and because the suspension of volition, which is the immediate cause of sleep, is sooner induced, after a continued voluntary exertion has in part exhausted the sensorial power of volition; in the same manner as we cannot contract a single muscle long together without intervals of inaction. 3. In the beginning of intoxication we are inclined to sleep, as mentioned above, but by the excitement of external circumstances, as of noise, light, business, or by the exertion of volition, we prevent the approaches of it, and continue to take into our stomach greater quantities of the inebriating materials. By these means the irritative movements of the stomach are excited into greater action than is natural; and in consequence all the irritative tribes and trains of motion, which are catenated with them, become susceptible of stronger action from their accustomed stimuli; because these motions are excited both by their usual irritation, and by their association with the increased actions of the stomach and lacteals. Hence the skin glows, and the heat of the body is increased, by the more energetic action of the whole glandular system; and pleasure is introduced in consequence of these increased motions from internal stimulus. According to Law 5. Sect. IV. on Animal Causation. From this great increase of irritative motions from internal stimulus, and the increased sensation introduced into the system in consequence; and secondly, from the increased sensitive motions in consequence of this additional quantity of sensation, so much sensorial power is expended, that the voluntary power becomes feebly exerted, and the irritation from the stimulus of external objects is less forcible; the external parts of the eye are not therefore voluntarily adapted to the distances of objects, whence the apparent motions of those objects either are seen double, or become too indistinct for the purpose of balancing the body, and vertigo is induced. Hence we become acquainted with that very curious circumstance, why the drunken vertigo is attended with an increase of pleasure; for the irritative ideas and motions occasioned by internal stimulus, that were not attended to in our sober hours, are now just so much increased as to be succeeded by pleasurable sensation, in the same manner as the more violent motions of our organs are succeeded by painful sensation. And hence a greater quantity of pleasurable sensation is introduced into the constitution; which is attended in some people with an increase of benevolence and good humour. If the apparent motions of objects is much increased, as when we revolve on one foot, or are swung on a rope, the ideas of these apparent motions are also attended to, and are succeeded with pleasureable sensation, till they become familiar to us by frequent use. Hence children are at first delighted with these kinds of exercise, and with riding, and failing, and hence rocking young children inclines them to sleep. For though in the vertigo from intoxication the irritative ideas of the apparent motions of objects are indistinct from their decrease of energy: yet in the vertigo occasioned by rocking or swinging the irritative ideas of the apparent motions of objects are increased in energy, and hence they induce pleasure into the system, but are equally indistinct, and in consequence equally unfit to balance ourselves by. This addition of pleasure precludes desire or aversion, and in consequence the voluntary power is feebly exerted, and on this account rocking young children inclines them to sleep. In what manner opium and wine act in relieving pain is another article, that well deserves our attention. There are many pains that originate from defect as well as from excess of stimulus; of these are those of the six appetites of hunger, thirst, lust, the want of heat, of distention, and of fresh air. Thus if our cutaneous capillaries cease to act from the diminished stimulus of heat, when we are exposed to cold weather, or our stomach is uneasy for want of food; these are both pains from defect of stimulus, and in consequence opium, which stimulates all the moving system into increased action, must relieve them. But this is not the case in those pains, which arise from excess of stimulus, as in violent inflammations: in these the exhibition of opium is frequently injurious by increasing the action of the system already too great, as in inflammation of the bowels mortification is often produced by the stimulus of opium. Where, however, no such bad consequences follow; the stimulus of opium, by increasing all the motions of the system, expends so much of the sensorial power, that the actions of the whole system soon become feebler, and in consequence those which produced the pain and inflammation. 4. When intoxication proceeds a little further, the quantity of pleasurable sensation is so far increased, that all desire ceases, for there is no pain in the system to excite it. Hence the voluntary exertions are diminished, staggering and stammering succeed; and the trains of ideas become more and more inconsistent from this defect of voluntary exertion, as explained in the sections on sleep and reverie, whilst those passions which are unmixed with volition are more vividly felt, and shewn with less reserve; hence pining love, or superstitious fear, and the maudling tear dropped on the remembrance of the most trifling distress. 5. At length all these circumstances are increased; the quantity of pleasure introduced into the system by the increased irritative muscular motions of the whole sanguiferous, and glandular, and absorbent systems, becomes so great, that the organs of sense are more forcibly excited into action by this internal pleasurable sensation, than by the irritation from the stimulus of external objects. Hence the drunkard ceases to attend to external stimuli, and as volition is now also suspended, the trains of his ideas become totally inconsistent as in dreams, or delirium: and at length a stupor succeeds from the great exhaustion of sensorial power, which probably does not even admit of dreams, and in which, as in apoplexy, no motions continue but those from internal stimuli, from sensation, and from association. 6. In other people a paroxysm of drunkenness has another termination; the inebriate, as soon as he begins to be vertiginous, makes pale urine in great quantities and very frequently, and at length becomes sick, vomits repeatedly, or purges, or has profuse sweats, and a temporary fever ensues with a quick strong pulse. This in some hours is succeeded by sleep; but the unfortunate bacchanalian does not perfectly recover himself till about the same time of the succeeding day, when his course of inebriation began. As shewn in Sect. XVII. 1. 7. on Catenation. The temporary fever with strong pulse is owing to the same cause as the glow on the skin mentioned in the third paragraph of this Section: the flow of urine and sickness arises from the whole system of irritative motions being thrown into confusion by their associations with each other; as in sea-sickness, mentioned in Sect. XX. 4. on Vertigo; and which is more fully explained in Section XXIX. on Diabetes. 7. In this vertigo from internal causes we see objects double, as two candles instead of one, which is thus explained. Two lines drawn through the axes of our two eyes meet at the object we attend to: this angle of the optic axes increases or diminishes with the less or greater distances of objects. All objects before or behind the place where this angle is formed, appear double; as any one may observe by holding up a pen between his eyes and the candle; when he looks attentively at a spot on the pen, and carelessly at the candle, it will appear double; and the reverse when he looks attentively at the candle and carelessly at the pen; so that in this case the muscles of the eye, like those of the limbs, stagger and are disobedient to the expiring efforts of volition. Numerous objects are indeed sometimes seen by the inebriate, occasioned by the refractions made by the tears, which stand upon his eye-lids. 8. This vertigo also continues, when the inebriate lies in his bed, in the dark, or with his eyes closed; and this more powerfully than when he is erect, and in the light. For the irritative ideas of the apparent motions of objects are now excited by irritation from internal stimulus, or by association with other irritative motions; and the inebriate, like one in a dream, believes the objects of these irritative motions to be present, and feels himself vertiginous. I have observed in this situation, so long as my eyes and mind were intent upon a book, the sickness and vertigo ceased, and were renewed again the moment I discontinued this attention; as was explained in the preceding account of sea-sickness. Some drunken people have been known to become sober instantly from some accident, that has strongly excited their attention, as the pain of a broken bone, or the news of their house being on fire. 9. Sometimes the vertigo from internal causes, as from intoxication, or at the beginning of some fevers, becomes so universal, that the irritative motions which belong to other organs of sense are succeeded by sensation or attention, as well as those of the eye. The vertiginous noise in the ears has been explained in Section XX. on Vertigo. The taste of the saliva, which in general is not attended to, becomes perceptible, and the patients complain of a bad taste in their mouth. The common smells of the surrounding air sometimes excite the attention of these patients, and bad smells are complained of, which to other people are imperceptible. The irritative motions that belong to the sense of pressure, or of touch, are attended to, and the patient conceives the bed to librate, and is fearful of falling out of it. The irritative motions belonging to the senses of distention, and of heat, like those above mentioned, become attended to at this time: hence we feel the pulsation of our arteries all over us, and complain of heat, or of cold, in parts of the body where there is no accumulation or diminution of actual heat. All which are to be explained, as in the last paragraph, by the irritative ideas belonging to the various senses being now excited by internal stimuli, or by their associations with other irritative motions. And that the inebriate, like one in a dream, believes the external objects, which usually caused these irritative ideas, to be now present. 10. The diseases in consequence of frequent inebriety, or of daily taking much vinous spirit without inebriety, consist in the paralysis, which is liable to succeed violent stimulation. Organs, whose actions are associated with others, are frequently more affected than the organ, which is stimulated into too violent action. See Sect. XXIV. 2. 8. Hence in drunken people it generally happens, that the secretory vessels of the liver become first paralytic, and a torpor with consequent gall-stones or schirrus of this viscus is induced with concomitant jaundice; otherwise it becomes inflamed in consequence of previous torpor, and this inflammation is frequently transferred to a more sensible part, which is associated with it, and produces the gout, or the rosy eruption of the face, or some other leprous eruption on the head, or arms, or legs. Sometimes the stomach is first affected, and paralysis of the lacteal system is induced: whence a total abhorrence from flesh-food, and general emaciation. In others the lymphatic system is affected with paralysis, and dropsy is the consequence. In some inebriates the torpor of the liver produces pain without apparent schirrus, or gall stones, or inflammation, or consequent gout, and in these epilepsy or insanity are often the consequence. All which will be more fully treated of in the course of the work. I am well aware, that it is a common opinion, that the gout is as frequently owing to gluttony in eating, as to intemperance in drinking fermented or spirituous liquors. To this I answer, that I have seen no person afflicted with the gout, who has not drank freely of fermented liquor, as wine and water, or small beer; though as the disposition to all the diseases, which have originated from intoxication, is in some degree hereditary, a less quantity of spirituous potation will induce the gout in those, who inherit the disposition from their parents. To which I must add, that in young people the rheumatism is frequently mistaken for the gout. Spice is seldom taken in such quantity as to do any material injury to the system, flesh-meats as well as vegetables are the natural diet of mankind; with these a glutton may be crammed up to the throat, and fed fat like a stalled ox; but he will not be diseased, unless he adds spirituous or fermented liquor to his food. This is well known in the distilleries, where the swine, which are fattened by the spirituous sediments of barrels, acquire diseased livers. But mark what happens to a man, who drinks a quart of wine or of ale, if he has not been habituated to it. He loses the use both of his limbs and of his understanding! He becomes a temporary idiot, and has a temporary stroke of the palsy! And though he slowly recovers after some hours, is it not reasonable to conclude, that a perpetual repetition of so powerful a poison must at length permanently affect him?--If a person accidentally becomes intoxicated by eating a few mushrooms of a peculiar kind, a general alarm is excited, and he is said to be poisoned, and emetics are exhibited; but so familiarised are we to the intoxication from vinous spirit, that it occasions laughter rather than alarm. There is however considerable danger in too hastily discontinuing the use of so strong a stimulus, lest the torpor of the system, or paralysis, should sooner be induced by the omission than by the continuance of this habit, when unfortunately acquired. A golden rule for determining the quantity, which may with safety be discontinued, is delivered in Sect. XII. 7. 8. 11. Definition of drunkenness. Many of the irritative motions are much increased in energy by internal stimulation. 2. A great additional quantity of pleasurable sensation is occasioned by this increased exertion of the irritative motions. And many sensitive motions are produced in consequence of this increased sensation. 3. The associated trains and tribes of motions, catenated with the increased irritative and sensitive motions, are disturbed, and proceed in confusion. 4. The faculty of volition is gradually impaired, whence proceeds the instability of locomotion, inaccuracy of perception, and inconsistency of ideas; and is at length totally suspended, and a temporary apoplexy succeeds. * * * * * SECT. XXII. OF PROPENSITY TO MOTION, REPETITION AND IMITATION. I. _Accumulation of sensorial power in hemiplagia, in sleep, in cold fit of fever, in the locomotive muscles, in the organs of sense. Produces propensity to action._ II. _Repetition by three sensorial powers. In rhimes and alliterations, in music, dancing, architecture, landscape-painting, beauty._ III. 1. _Perception consists in imitation. Four kinds of imitation._ 2. _Voluntary. Dogs taught to dance._ 3. _Sensitive. Hence sympathy, and all our virtues. Contagious matter of venereal ulcers, of hydrophobia, of jail-fever, of small-pox, produced by imitation, and the sex of the embryon._ 4. _Irritative imitation._ 5. _Imitations resolvable into associations._ I. 1. In the hemiplagia, when the limbs on one side have lost their power of voluntary motion, the patient is for many days perpetually employed in moving those of the other. 2. When the voluntary power is suspended during sleep, there commences a ceaseless flow of sensitive motions, or ideas of imagination, which compose our dreams. 3. When in the cold fit of an intermittent fever some parts of the system have for a time continued torpid, and have thus expended less than their usual expenditure of sensorial power; a hot fit succeeds, with violent action of those vessels, which had previously been quiescent. All these are explained from an accumulation of sensorial power during the inactivity of some part of the system. Besides the very great quantity of sensorial power perpetually produced and expended in moving the arterial, venous, and glandular systems, with the various organs or digestion, as described in Section XXXII. 3. 2. there is also a constant expenditure of it by the action of our locomotive muscles and organs of sense. Thus the thickness of the optic nerves, where they enter the eye, and the great expansion of the nerves of touch beneath the whole of the cuticle, evince the great consumption of sensorial power by these senses. And our perpetual muscular actions in the common offices of life, and in constantly preserving the perpendicularity of our bodies during the day, evince a considerable expenditure of the spirit of animation by our locomotive muscles. It follows, that if the exertion of these organs of sense and muscles be for a while intermitted, that some quantity of sensorial power must be accumulated, and a propensity to activity of some kind ensue from the increased excitability of the system. Whence proceeds the irksomeness of a continued attitude, and of an indolent life. However small this hourly accumulation of the spirit of animation may be, it produces a propensity to some kind of action; but it nevertheless requires either desire or aversion, either pleasure or pain, or some external stimulus, or a previous link of association, to excite the system into activity; thus it frequently happens, when the mind and body are so unemployed as not to possess any of the three first kinds of stimuli, that the last takes place, and consumes the small but perpetual accumulation of sensorial power. Whence some indolent people repeat the same verse for hours together, or hum the same tune. Thus the poet: Onward he trudged, not knowing what he sought, And whistled, as he went, for want of thought. II. The repetitions of motions may be at first produced either by volition, or by sensation, or by irritation, but they soon become easier to perform than any other kinds of action, because they soon become associated together, according to Law the seventh, Section IV. on Animal Causation. And because their frequency of repetition, if as much sensorial power be produced during every reiteration as is expended, adds to the facility of their production. If a stimulus be repeated at uniform intervals of time, as described in Sect. XII. 3. 3. the action, whether of our muscles or organs of sense, is produced with still greater facility or energy; because the sensorial power of association, mentioned above, is combined with the sensorial power of irritation; that is, in common language, the acquired habit assists the power of the stimulus. This not only obtains in the annual, lunar, and diurnal catenations of animal motions, as explained in Sect. XXXVI. which are thus performed with great facility and energy; but in every less circle of actions or ideas, as in the burthen of a song, or the reiterations of a dance. To the facility and distinctness, with which we hear sounds at repeated intervals, we owe the pleasure, which we receive from musical time, and from poetic time; as described in Botanic Garden, P. 2. Interlude 3. And to this the pleasure we receive from the rhimes and alliterations of modern verification; the source of which without this key would be difficult to discover. And to this likewise should be ascribed the beauty of the duplicature in the perfect tense of the Greek verbs, and of some Latin ones, as tango tetegi, mordeo momordi. There is no variety of notes referable to the gamut in the beating of the drum, yet if it be performed in musical time, it is agreeable to our ears; and therefore this pleasurable sensation must be owing to the repetition of the divisions of the sounds at certain intervals of time, or musical bars. Whether these times or bars are distinguished by a pause, or by an emphasis, or accent, certain it is, that this distinction is perpetually repeated; otherwise the ear could not determine instantly, whether the successions of sound were in common or in triple time. In common time there is a division between every two crotchets, or other notes of equivalent time; though the bar in written music is put after every fourth crotchet, or notes equivalent in time; in triple time the division or bar is after every three crotchets, or notes equivalent; so that in common time the repetition recurs more frequently than in triple time. The grave or heroic verses of the Greek and Latin poets are written in common time; the French heroic verses, and Mr. Anstie's humorous verses in his Bath Guide, are written in the same time as the Greek and Latin verses, but are one bar shorter. The English grave or heroic verses are measured by triple time, as Mr. Pope's translation of Homer. But besides these little circles of musical time, there are the greater returning periods, and the still more distant choruses, which, like the rhimes at the ends of verses, owe their beauty to repetition; that is, to the facility and distinctness with which we perceive sounds, which we expect to perceive, or have perceived before; or in the language of this work, to the greater ease and energy with which our organ is excited by the combined sensorial powers of association and irritation, than by the latter singly. A certain uniformity or repetition of parts enters the very composition of harmony. Thus two octaves nearest to each other in the scale commence their vibrations together after every second vibration of the higher one. And where the first, third, and fifth compose a chord the vibrations concur or coincide frequently, though less to than in the two octaves. It is probable that these chords bear some analogy to a mixture of three alternate colours in the sun's spectrum separated by a prism. The pleasure we receive from a melodious succession of notes referable to the gamut is derived from another source, viz. to the pandiculation or counteraction of antagonist fibres. See Botanic Garden, P. 2. Interlude 3. If to these be added our early associations of agreeable ideas with certain proportions of sound, I suppose, from these three sources springs all the delight of music, so celebrated by ancient authors, and so enthusiastically cultivated at present. See Sect. XVI. No. 10. on Instinct. This kind of pleasure arising from repetition, that is from the facility and distinctness, with which we perceive and understand repeated sensations, enters into all the agreeable arts; and when it is carried to excess is termed formality. The art of dancing like that of music depends for a great part of the pleasure, it affords, on repetition; architecture, especially the Grecian, consists of one part being a repetition of another; and hence the beauty of the pyramidal outline in landscape-painting; where one side of the picture may be said in some measure to balance the other. So universally does repetition contribute to our pleasure in the fine arts, that beauty itself has been defined by some writers to consist in a due combination of uniformity and variety. See Sect. XVI. 6. III. 1. Man is termed by Aristotle an imitative animal; this propensity to imitation not only appears in the actions of children, but in all the customs and fashions of the world: many thousands tread in the beaten paths of others, for one who traverses regions of his own discovery. The origin of this propensity of imitation has not, that I recollect, been deduced from any known principle; when any action presents itself to the view of a child, as of whetting a knife, or threading a needle, the parts of this action in respect of time, motion, figure, is imitated by a part of the retina of his eye; to perform this action therefore with his hands is easier to him than to invent any new action, because it consists in repeating with another set of fibres, viz. with the moving muscles, what he had just performed by some parts of the retina; just as in dancing we transfer the times of motion from the actions of the auditory nerves to the muscles of the limbs. Imitation therefore consists of repetition, which we have shewn above to be the easiest kind of animal action, and which we perpetually fall into, when we possess an accumulation of sensorial power, which is not otherwise called into exertion. It has been shewn, that our ideas are configurations of the organs of sense, produced originally in consequence of the stimulus of external bodies. And that these ideas, or configurations of the organs of sense, referable in some property a correspondent property of external matter; as the parts of the senses of light and of touch, which are excited into action, resemble in figure the figure of the stimulating body; and probably also the colour, and the quantity of density, which they perceive. As explained in Sect. XIV. 2. 2. Hence it appears, that our perceptions themselves are copies, that is, imitations of some properties of external matter; and the propensity to imitation is thus interwoven with our existence, as it is produced by the stimuli of external bodies, and is afterwards repeated by our volitions and sensations, and thus constitutes all the operations of our minds. 2. Imitations resolve themselves into four kinds, voluntary, sensitive, irritative, and associate. The voluntary imitations are, when we imitate deliberately the actions of others, either by mimicry, as in acting a play, or in delineating a flower; or in the common actions of our lives, as in our dress, cookery, language, manners, and even in our habits of thinking. Not only the greatest part of mankind learn all the common arts of life by imitating others, but brute animals seem capable of acquiring knowledge with greater facility by imitating each other, than by any methods by which we can teach them; as dogs and cats, when they are sick, learn of each other to eat grass; and I suppose, that by making an artificial dog perform certain tricks, as in dancing on his hinder legs, a living dog might be easily induced to imitate them; and that the readiest way of instructing dumb animals is by practising them with others of the same species, which have already learned the arts we wish to teach them. The important use of imitation in acquiring natural language is mentioned in Section XVI. 7. and 8. on Instinct. 3. The sensitive imitations are the immediate consequences of pleasure or pain, and these are often produced even contrary to the efforts of the will. Thus many young men on seeing cruel surgical operations become sick, and some even feel pain in the parts of their own bodies, which they see tortured or wounded in others; that is, they in some measure imitate by the exertions of their own fibres the violent actions, which they witnessed in those of others. In this case a double imitation takes place, first the observer imitates with the extremities of the optic nerve the mangled limbs, which are present before his eyes; then by a second imitation he excites to violent action of the fibres of his own limbs as to produce pain in those parts of his own body, which he saw wounded in another. In these pains produced by imitation the effect has some similarity to the cause, which distinguishes them from those produced by association; as the pains of the teeth, called tooth-edge, which are produced by association with disagreeable sounds, as explained in Sect. XVI. 10. The effect of this powerful agent, imitation, in the moral world, is mentioned in Sect. XVI. 7. as it is the foundation of all our intellectual sympathies with the pains and pleasures of others, and is in consequence the source of all our virtues. For in what consists our sympathy with the miseries, or with the joys, of our fellow creatures, but in an involuntary excitation of ideas in some measure similar or imitative of those, which we believe to exist in the minds of the persons, whom we commiserate or congratulate? There are certain concurrent or successive actions of some of the glands, or other parts of the body, which are possessed of sensation, which become intelligible from this propensity to imitation. Of these are the production of matter by the membranes of the fauces, or by the skin, in consequence of the venereal disease previously affecting the parts of generation. Since as no fever is excited, and as neither the blood of such patients, nor even the matter from ulcers of the throat, or from cutaneous ulcers, will by inoculation produce the venereal disease in others, as observed by Mr. Hunter, there is reason to conclude, that no contagious matter is conveyed thither by the blood-vessels, but that a milder matter is formed by the actions of the fine vessels in those membranes imitating each other. See Section XXXIII. 2. 9. In this disease the actions of these vessels producing ulcers on the throat and skin are imperfect imitations of those producing chanker, or gonorrhoea; since the matter produced by them is not infectious, while the imitative actions in the hydrophobia appear to be perfect resemblances, as they produce a material equally infectious with the original one, which induced them. The contagion from the bite of a mad dog differs from other contagious materials, from its being communicable from other animals to mankind, and from many animals to each other; the phenomena attending the hydrophobia are in some degree explicable on the foregoing theory. The infectious matter does not appear to enter the circulation, as it cannot be traced along the course of the lymphatics from the wound, nor is there any swelling of the lymphatic glands, nor does any fever attend, as occurs in the small-pox, and in many other contagious diseases; yet by some unknown process the disease is communicated from the wound to the throat, and that many months after the injury, so as to produce pain and hydrophobia, with a secretion of infectious saliva of the same kind, as that of the mad dog, which inflicted the wound. This subject is very intricate.--It would appear, that by certain morbid actions of the salivary glands of the mad dog, a peculiar kind of saliva is produced; which being instilled into a wound of another animal stimulates the cutaneous or mucous glands into morbid actions, but which are ineffectual in respect to the production of a similar contagious material; but the salivary glands by irritative sympathy are thrown into similar action, and produce an infectious saliva similar to that instilled into the wound. Though in many contagious fevers a material similar to that which produced the disease, is thus generated by imitation; yet there are other infectious materials, which do not thus propagate themselves, but which seem to act like slow poisons. Of this kind was the contagious matter, which produced the jail-fever at the assizes at Oxford about a century ago. Which, though fatal to so many, was not communicated to their nurses or attendants. In these cases, the imitations of the fine vessels, as above described, appear to be imperfect, and do not therefore produce a matter similar to that, which stimulates them; in this circumstance resembling the venereal matter in ulcers of the throat or skin, according to the curious discovery of Mr. Hunter above related, who found, by repeated inoculations, that it would not infect. Hunter on Venereal Disease, Part vi. ch. 1. Another example of morbid imitation is in the production of a great quantity of contagious matter, as in the inoculated small-pox, from a small quantity of it inserted into the arm, and probably diffused in the blood. These particles of contagious matter stimulate the extremities of the fine arteries of the skin, and cause them to imitate some properties of those particles of contagious matter, so as to produce a thousandfold of a similar material. See Sect. XXXIII. 2. 6. Other instances are mentioned in the Section on Generation, which shew the probability that the extremities of the seminal glands may imitate certain ideas of the mind, or actions of the organs of sense, and thus occasion the male or female sex of the embryon. See Sect. XXXIX. 6. 4. We come now to those imitations, which are not attended with sensation. Of these are all the irritative ideas already explained, as when the retina of the eye imitates by its action or configuration the tree or the bench, which I shun in walking past without attending to them. Other examples of these irritative imitations are daily observable in common life; thus one yawning person shall set a whole company a yawning; and some have acquired winking of the eyes or impediments of speech by imitating their companions without being conscious of it. 5. Besides the three species of imitations above described there may be some associate motions, which may imitate each other in the kind as well as in the quantity of their action; but it is difficult to distinguish them from the associations of motions treated of in Section XXXV. Where the actions of other persons are imitated there can be no doubt, or where we imitate a preconceived idea by exertion of our locomotive muscles, as in painting a dragon; all these imitations may aptly be referred to the sources above described of the propensity to activity, and the facility of repetition; at the same time I do not affirm, that all those other apparent sensitive and irritative imitations may not be resolvable into associations of a peculiar kind, in which certain distant parts of similar irritability or sensibility, and which have habitually acted together, may affect each other exactly with the same kinds of motion; as many parts are known to sympathise in the quantity of their motions. And that therefore they may be ultimately resolvable into associations of action, as described in Sect. XXXV. * * * * * SECT. XXIII. OF THE CIRCULATORY SYSTEM. I. _The heart and arteries have no antagonist muscles. Veins absorb the blood, propel it forwards, and distend the heart; contraction of the heart distends the arteries. Vena portarum._ II. _Glands which take their fluids from the blood. With long necks, with short necks._ III. _Absorbent system._ IV. _Heat given out from glandular secretions. Blood changes colour in the lungs and in the glands and capillaries._ V. _Blood is absorbed by veins, as chyle by lacteal vessels, otherwise they could not join their streams._ VI. _Two kinds of stimulus, agreeable and disagreeable. Glandular appetency. Glands originally possessed sensation._ I. We now step forwards to illustrate some of the phenomena of diseases, and to trace out their most efficacious methods of cure; and shall commence this subject with a short description of the circulatory system. As the nerves, whose extremities form our various organs of sense and muscles, are all joined, or communicate, by means of the brain, for the convenience perhaps of the distribution of a subtile ethereal fluid for the purpose of motion; so all those vessels of the body, which carry the grosser fluids for the purposes of nutrition, communicate with each other by the heart. The heart and arteries are hollow muscles, and are therefore indued with power of contraction in consequence of stimulus, like all other muscular fibres; but, as they have no antagonist muscles, the cavities of the vessels, which they form, would remain for ever closed, after they have contracted themselves, unless some extraneous power be applied to again distend them. This extraneous power in respect to the heart is the current of blood, which is perpetually absorbed by the veins from the various glands and capillaries, and pushed into the heart by a power probably very similar to that, which raises the sap in vegetables in the spring, which, according to Dr. Hale's experiment on the stump of a vine, exerted a force equal to a column of water above twenty feet high. This force of the current of blood in the veins is partly produced by their absorbent power, exerted at the beginning of every fine ramification; which may be conceived to be a mouth absorbing blood, as the mouths of the lacteals and lymphatics absorb chyle and lymph. And partly by their intermitted compression by the pulsations of their generally concomitant arteries; by which the blood is perpetually propelled towards the heart, as the valves in many veins, and the absorbent mouths in them all, will not suffer it to return. The blood, thus forcibly injected into the chambers of the heart, distends this combination of hollow muscles; till by the stimulus of distention they contract themselves; and, pushing forwards the blood into the arteries, exert sufficient force to overcome in less than a second of time the vis inertiæ, and perhaps some elasticity, of the very extensive ramifications of the two great systems of the aortal and pulmonary arteries. The power necessary to do this in so short a time must be considerable, and has been variously estimated by different physiologists. The muscular coats of the arterial system are then brought into action by the stimulus of distention, and propel the blood to the mouths, or through the convolutions, which precede the secretory apertures of the various glands and capillaries. In the vessels of the liver there is no intervention of the heart; but the vena portarum, which does the office of an artery, is distended by the blood poured into it from the mesenteric veins, and is by this distention stimulated to contract itself, and propel the blood to the mouths of the numerous glands, which compose that viscus. II. The glandular system of vessels may be divided into those, which take some fluid from the circulation; and those, which give something to it. Those, which take their fluid from the circulation are the various glands, by which the tears, bile, urine, perspiration, and many other secretions are produced; these glands probably consist of a mouth to select, a belly to digest, and an excretory aperture to emit their appropriated fluids; the blood is conveyed by the power of the heart and arteries to the mouths of these glands, it is there taken up by the living power of the gland, and carried forwards to its belly, and excretory aperture, where a part is separated, and the remainder absorbed by the veins for further purposes. Some of these glands are furnished with long convoluted necks or tubes, as the seminal ones, which are curiously seen when injected with quicksilver. Others seem to consist of shorter tubes, as that great congeries of glands, which constitute the liver, and those of the kidneys. Some have their excretory apertures opening into reservoirs, as the urinary and gall-bladders. And others on the external body, as those which secrete the tears, and perspirable matter. Another great system of glands, which have very short necks, are the capillary vessels; by which the insensible perspiration is secreted on the skin; and the mucus of various consistences, which lubricates the interstices of the cellular membrane, of the muscular fibres, and of all the larger cavities of the body. From the want of a long convolution of vessels some have doubted, whether these capillaries should be considered as glands, and have been led to conclude, that the perspirable matter rather exuded than was secreted. But the fluid of perspiration is not simple water, though that part of it, which exhales into the air may be such; for there is another part of it, which in a state of health is absorbed again; but which, when the absorbents are diseased, remains on the surface of the skin, in the form of scurf, or indurated mucus. Another thing, which shews their similitude to other glands, is their sensibility to certain affections of the mind; as is seen in the deeper colour of the skin in the blush of shame, or the greater paleness of it from fear. III. Another series of glandular vessels is called the absorbent system; these open their mouths into all the cavities, and upon all those surfaces of the body, where the excretory apertures of the other glands pour out their fluids. The mouths of the absorbent system drink up a part or the whole of these fluids, and carry them forwards by their living power to their respective glands, which are called conglobate glands. There these fluids undergo some change, before they pass on into the circulation; but if they are very acrid, the conglobate gland swells, and sometimes suppurates, as in inoculation of the small-pox, in the plague, and in venereal absorptions; at other times the fluid may perhaps continue there, till it undergoes some chemical change, that renders it less noxious; or, what is more likely, till it is regurgitated by the retrograde motion of the gland in spontaneous sweats or diarrhoeas, as disagreeing food is vomited from the stomach. IV. As all the fluids, that pass through these glands, and capillary vessels, undergo a chemical change, acquiring new combinations, the matter of heat is at the same time given out; this is apparent, since whatever increases insensible perspiration, increases the heat of the skin; and when the action of these vessels is much increased but for a moment, as in blushing, a vivid heat on the skin is the immediate consequence. So when great bilious secretions, or those of any other gland, are produced, heat is generated in the part in proportion to the quantity of the secretion. The heat produced on the skin by blushing may be thought by some too sudden to be pronounced a chemical effect, as the fermentations or new combinations taking place in a fluid is in general a slower process. Yet are there many chemical mixtures in which heat is given out as instantaneously; as in solutions of metals in acids, or in mixtures of essential oils and acids, as of oil of cloves and acid of nitre. So the bruised parts of an unripe apple become almost instantaneously sweet; and if the chemico-animal process of digestion be stopped for but a moment, as by fear, or even by voluntary eructation, a great quantity of air is generated, by the fermentation, which instantly succeeds the stop of digestion. By the experiments of Dr. Hales it appears, that an apple during fermentation gave up above six hundred times its bulk of air; and the materials in the stomach are such, and in such a situation, as immediately to run into fermentation, when digestion is impeded. As the blood passes through the small vessels of the lungs, which connect the pulmonary artery and vein, it undergoes a change of colour from a dark to a light red; which may be termed a chemical change, as it is known to be effected by an admixture of oxygene, or vital air; which, according to a discovery of Dr. Priestley, passes through the moist membranes, which constitute the sides of these vessels. As the blood passes through the capillary vessels, and glands, which connect the aorta and its various branches with their correspondent veins in the extremities of the body, it again loses the bright red colour, and undergoes some new combinations in the glands or capillaries, in which the matter of heat is given out from the secreted fluids. This process therefore, as well as the process of respiration, has some analogy to combustion, as the vital air or oxygene seems to become united to some inflammable base, and the matter of heat escapes from the new acid, which is thus produced. V. After the blood has passed these glands and capillaries, and parted with whatever they chose to take from it, the remainder is received by the veins, which are a set of blood-absorbing vessels in general corresponding with the ramifications of the arterial system. At the extremity of the fine convolutions of the glands the arterial force ceases; this in respect to the capillary vessels, which unite the extremities of the arteries with the commencement of the veins, is evident to the eye, on viewing the tail of a tadpole by means of a solar, or even by a common microscope, for globules of blood are seen to endeavour to pass, and to return again and again, before they become absorbed by the mouths of the veins; which returning of these globules evinces, that the arterial force behind them has ceased. The veins are furnished with valves like the lymphatic absorbents; and the great trunks of the veins, and of the lacteals and lymphatics, join together before the ingress of their fluids into the left chamber of the heart; both which evince, that the blood in the veins, and the lymph and chyle in the lacteals and lymphatics, are carried on by a similar force; otherwise the stream, which was propelled with a less power, could not enter the vessels, which contained the stream propelled with a greater power. From whence it appears, that the veins are a system of vessels absorbing blood, as the lacteals and lymphatics are a system of vessels absorbing chyle and lymph. See Sect. XXVII. 1. VI. The movements of their adapted fluids in the various vessels of the body are carried forwards by the actions of those vessels in consequence of two kinds of stimulus, one of which may be compared to a pleasurable sensation or desire inducing the vessel to seize, and, as it were, to swallow the particles thus selected from the blood; as is done by the mouths of the various glands, veins, and other absorbents, which may be called glandular appetency. The other kind of stimulus may be compared to disagreeable sensation, or aversion, as when the heart has received the blood, and is stimulated by it to push it forwards into the arteries; the same again stimulates the arteries to contract, and carry forwards the blood to their extremities, the glands and capillaries. Thus the mesenteric veins absorb the blood from the intestines by glandular appetency, and carry it forward to the vena portarum; which acting as an artery contracts itself by disagreeable stimulus, and pushes it to its ramified extremities, the various glands, which constitute the liver. It seems probable, that at the beginning of the formation of these vessels in the embryon, an agreeable sensation was in reality felt by the glands during secretion, as is now felt in the act of swallowing palatable food; and that a disagreeable sensation was originally felt by the heart from the distention occasioned by the blood, or by its chemical stimulus; but that by habit these are all become irritative motions; that is, such motions as do not affect the whole system, except when the vessels are diseased by inflammation. * * * * * SECT. XXIV. OF THE SECRETIONS OF SALIVA, AND OF TEARS, AND OF THE LACRYMAL SACK. I. _Secretion of saliva increased by mercury in the blood._ 1. _By the food in the mouth. Dryness of the mouth not from a deficiency of saliva._ 2. _By Sensitive ideas._ 3. _By volition._ 4. _By distasteful substances. It is secreted in a dilute and saline state. It then becomes more viscid._ 5. _By ideas of distasteful substances._ 6. _By nausea._ 7. _By aversion._ 8. _By catenation with stimulating substances in the ear._ II. 1. _Secretion of tears less in sleep. From stimulation of their excretory duct._ 2. _Lacrymal sack is a gland._ 3. _Its uses._ 4. _Tears are secreted, when the nasal duct is stimulated._ 5. _Or when it is excited by sensation._ 6. _Or by volition._ 7. _The lacrymal sack can regurgitate its contents into the eye._ 8. _More tears are secreted by association with the irritation of the nasal duct of the lacrymal sack, than the puncta lacrymalia can imbibe. Of the gout in the liver and stomach._ I. The salival glands drink up a certain fluid from the circumfluent blood, and pour it into the mouth. They are sometimes stimulated into action by the blood, that surrounds their origin, or by some part of that heterogeneous fluid: for when mercurial salts, or oxydes, are mixed with the blood, they stimulate these glands into unnatural exertions; and then an unusual quantity of saliva is separated. 1. As the saliva secreted by these glands is most wanted during the mastication of our food, it happens, when the terminations of their ducts in the mouth are stimulated into action, the salival glands themselves are brought into increased action at the same time by association, and separate a greater quantity of their juices from the blood; in the same manner as tears are produced in greater abundance during the stimulus of the vapour of onions, or of any other acrid material in the eye. The saliva is thus naturally poured into the mouth only during the stimulus of our food in mastication; for when there is too great an exhalation of the mucilaginous secretion from the membranes, which line the mouth, or too great an absorption of it, the mouth becomes dry, though there is no deficiency in the quantity of saliva; as in those who sleep with their mouths open, and in some fevers. 2. Though during the mastication of our natural food the salival glands are excited into action by the stimulus on their excretory ducts, and a due quantity of saliva is separated from the blood, and poured into the mouth; yet as this mastication of our food is always attended with a degree of pleasure; and that pleasurable sensation is also connected with our ideas of certain kinds of aliment; it follows, that when these ideas are reproduced, the pleasurable sensation arises along with them, and the salival glands are excited into action, and fill the mouth with saliva from this sensitive association, as is frequently seen in dogs, who slaver at the sight of food. 3. We have also a voluntary power over the action of these salival glands, for we can at any time produce a flow of saliva into our mouth, and spit out, or swallow it at will. 4. If any very acrid material be held in the mouth, as the root of pyrethrum, or the leaves of tobacco, the salival glands are stimulated into stronger action than is natural, and thence secrete a much larger quantity of saliva; which is at the same time more viscid than in its natural state; because the lymphatics, that open their mouths into the ducts of the salival glands, and on the membranes, which line the mouth, are likewise stimulated into stronger action, and absorb the more liquid parts of the saliva with greater avidity; and the remainder is left both in greater quantity and more viscid. The increased absorption in the mouth by some stimulating substances, which are called astringents, as crab juice, is evident from the instant dryness produced in the mouth by a small quantity of them. As the extremities of the glands are of exquisite tenuity, as appears by their difficulty of injection, it was necessary for them to secrete their fluids in a very dilute state; and, probably for the purpose of stimulating them into action, a quantity of neutral salt is likewise secreted or formed by the gland. This aqueous and saline part of all secreted fluids is again reabsorbed into the habit. More than half of some secreted fluids is thus imbibed from the reservoirs, into which they are poured; as in the urinary bladder much more than half of what is secreted by the kidneys becomes reabsorbed by the lymphatics, which are thickly dispersed around the neck of the bladder. This seems to be the purpose of the urinary bladders of fish, as otherwise such a receptacle for the urine could have been of no use to an animal immersed in water. 5. The idea of substances disagreeably acrid will also produce a quantity of saliva in the mouth; as when we smell very putrid vapours, we are induced to spit out our saliva, as if something disagreeable was actually upon our palates. 6. When disagreeable food in the stomach produces nausea, a flow of saliva is excited in the mouth by association; as efforts to vomit are frequently produced by disagreeable drugs in the mouth by the same kind of association. 7. A preternatural flow of saliva is likewise sometimes occasioned by a disease of the voluntary power; for if we think about our saliva, and determine not to swallow it, or not to spit it out, an exertion is produced by the will, and more saliva is secreted against our wish; that is, by our aversion, which bears the same analogy to desire, as pain does to pleasure; as they are only modifications of the same disposition of the sensorium. See Class IV. 3. 2. 1. 8. The quantity of saliva may also be increased beyond what is natural, by the catenation of the motions of these glands with other motions, or sensations, as by an extraneous body in the ear; of which I have known an instance; or by the application of stizolobium, siliqua hirsuta, cowhage, to the seat of the parotis, as some writers have affirmed. II. 1. The lacrymal gland drinks up a certain fluid from the circumfluent blood, and pours it on the ball of the eye, on the upper part of the external corner of the eyelids. Though it may perhaps be stimulated into the performance of its natural action by the blood, which surrounds its origin, or by some part of that heterogeneous fluid; yet as the tears secreted by this gland are more wanted at some times than at others, its secretion is variable, like that of the saliva above mentioned, and is chiefly produced when its excretory duct is stimulated; for in our common sleep there seems to be little or no secretion of tears; though they are occasionally produced by our sensations in dreams. Thus when any extraneous material on the eye-ball, or the dryness of the external covering of it, or the coldness of the air, or the acrimony of some vapours, as of onions, stimulates the excretory duct of the lacrymal gland, it discharges its contents upon the ball; a quicker secretion takes place in the gland, and abundant tears succeed, to moisten, clean, and lubricate the eye. These by frequent nictitation are diffused over the whole ball, and as the external angle of the eye in winking is closed sooner than the internal angle, the tears are gradually driven forwards, and downwards from the lacrymal gland to the puncta lacrymalia. 2. The lacrymal sack, with its puncta lacrymalia, and its nasal duct, is a complete gland; and is singular in this respect, that it neither derives its fluid from, nor disgorges it into the circulation. The simplicity of the structure of this gland, and both the extremities of it being on the surface of the body, makes it well worthy our minuter observation; as the actions of more intricate and concealed glands may be better understood from their analogy to this. 3. This simple gland consists of two absorbing mouths, a belly, and an excretory duct. As the tears are brought to the internal angle of the eye, these two mouths drink them up, being stimulated into action by this fluid, which they absorb. The belly of the gland, or lacrymal sack, is thus filled, in which the saline part of the tears is absorbed, and when the other end of the gland, or nasal duct, is stimulated by the dryness, or pained by the coldness of the air, or affected by any acrimonious dust or vapour in the nostrils, it is excited into action together with the sack, and the tears are disgorged upon the membrane, which lines the nostrils; where they serve a second purpose to moisten, clean, and lubricate, the organ of smell. 4. When the nasal duct of this gland is stimulated by any very acrid material, as the powder of tobacco, or volatile spirits, it not only disgorges the contents of its belly or receptacle (the lacrymal sack), and absorbs hastily all the fluid, that is ready for it in the corner of the eye; but by the association of its motions with those of the lacrymal gland, it excites that also into increased action, and a large flow of tears is poured into the eye. 5. This nasal duct is likewise excited into strong action by sensitive ideas, as in grief, or joy, and then also by its associations with the lacrymal gland it produces a great flow of tears without any external stimulus; as is more fully explained in Sect. XVI. 8. on Instinct. 6. There are some, famous in the arts of exciting compassion, who are said to have acquired a voluntary power of producing a flow of tears in the eye; which, from what has been said in the section on Instinct above mentioned, I should suspect, is performed by acquiring a voluntary power over the action of this nasal duct. 7. There is another circumstance well worthy our attention, that when by any accident this nasal duct is obstructed, the lacrymal sack, which is the belly or receptacle of this gland, by slight pressure of the finger is enabled to disgorge its contents again into the eye; perhaps the bile in the same manner, when the biliary ducts are obstructed, is returned into the blood by the vessels which secrete it? 8. A very important though minute occurrence must here be observed, that though the lacrymal gland is only excited into action, when we weep at a distressful tale, by its association with this nasal duct, as is more fully explained in Sect. XVI. 8; yet the quantity of tears secreted at once is more than the puncta lacrymalia can readily absorb; which shews _that the motions occasioned by associations are frequently more energetic than the original motions, by which they were occasioned_. Which we shall have occasion to mention hereafter, to illustrate, why pains frequently exist in a part distant from the cause of them, as in the other end of the urethra, when a stone stimulates the neck of the bladder. And why inflammations frequently arise in parts distant from their cause, as the gutta rosea of drinking people, from an inflamed liver. The inflammation of a part is generally preceded by a torpor or quiescence of it; if this exists in any large congeries of glands, as in the liver, or any membranous part, as the stomach, pain is produced and chilliness in consequence of the torpor of the vessels. In this situation sometimes an inflammation of the parts succeeds the torpor; at other times a distant more sensible part becomes inflamed; whose actions have previously been associated with it; and the torpor of the first part ceases. This I apprehend happens, when the gout of the foot succeeds a pain of the biliary duct, or of the stomach. Lastly, it sometimes happens, that the pain of torpor exists without any consequent inflammation of the affected part, or of any distant part associated with it, as in the membranes about the temple and eye-brows in hemicrania, and in those pains, which occasion convulsions; if this happens to gouty people, when it affects the liver, I suppose epileptic fits are produced; and, when it affects the stomach, death is the consequence. In these cases the pulse is weak, and the extremities cold, and such medicines as stimulate the quiescent parts into action, or which induce inflammation in them, or in any distant part, which is associated with them, cures the present pain of torpor, and saves the patient. I have twice seen a gouty inflammation of the liver, attended with jaundice; the patients after a few days were both of them affected with cold fits, like ague-fits, and their feet became affected with gout, and the inflammation of their livers ceased. It is probable, that the uneasy sensations about the stomach, and indigestion, which precedes gouty paroxysms, are generally owing to torpor or slight inflammation of the liver, and biliary ducts; but where great pain with continued sickness, with feeble pulse, and sensation of cold, affect the stomach in patients debilitated by the gout, that it is a torpor of the stomach itself, and destroys the patient from the great connexion of that viscus with the vital organs. See Sect. XXV. 17. * * * * * SECT. XXV. OF THE STOMACH AND INTESTINES. 1. _Of swallowing our food. Ruminating animals._ 2. _Action of the stomach._ 3. _Action of the intestines. Irritative motions connected with these._ 4. _Effects of repletion._ 5. _Stronger action of the stomach and intestines from more stimulating food._ 6. _Their action inverted by still greater stimuli. Or by disgustful ideas. Or by volition._ 7. _Other glands strengthen or invert their motions by sympathy._ 8. _Vomiting performed by intervals._ 9. _Inversion of the cutaneous absorbents._ 10. _Increased secretion of bile and pancreatic juice._ 11. _Inversion of the lacteals._ 12. _And of the bile-ducts._ 13. _Case of a cholera._ 14. _Further account of the inversion of lacteals._ 15. _Iliac passions. Valve of the colon._ 16. _Cure of the iliac passion._ 17. _Pain of gall-stone distinguished from pain of the stomach. Gout of the stomach from torpor, from inflammation. Intermitting pulse owing to indigestion. To overdose of foxglove. Weak pulse from emetics. Death from a blow on the stomach. From gout of the stomach._ 1. The throat, stomach, and intestines, may be considered as one great gland; which like the lacrymal sack above mentioned, neither begins nor ends in the circulation. Though the act of masticating our aliment belongs to the sensitive class of motions, for the pleasure of its taste induces the muscles of the jaw into action; yet the deglutition of it when masticated is generally, if not always, an irritative motion, occasioned by the application of the food already masticated to the origin of the pharinx; in the same manner as we often swallow our spittle without attending to it. The ruminating class of animals have the power to invert the motion of their gullet, and of their first stomach, from the stimulus of this aliment, when it is a little further prepared; as is their daily practice in chewing the cud; and appears to the eye of any one, who attends to them, whilst they are employed in this second mastication of their food. 2. When our natural aliment arrives into the stomach, this organ is simulated into its proper vermicular action; which beginning at the upper orifice of it, and terminating at the lower one, gradually mixes together and pushes forwards the digesting materials into the intestine beneath it. At the same time the glands, that supply the gastric juices, which are necessary to promote the chemical part of the process of digestion, are stimulated to discharge their contained fluids, and to separate a further supply from the blood-vessels: and the lacteals or lymphatics, which open their mouths into the stomach, are stimulated into action, and take up some part of the digesting materials. 3. The remainder of these digesting materials is carried forwards into the upper intestines, and stimulates them into their peristaltic motion similar to that of the stomach; which continues gradually to mix the changing materials, and pass them along through the valve of the colon to the excretory end of this great gland, the sphincter ani. The digesting materials produce a flow of bile, and of pancreatic juice, as they pass along the duodenum, by stimulating the excretory ducts of the liver and pancreas, which terminate in that intestine: and other branches of the absorbent or lymphatic system, called lacteals, are excited to drink up, as it passes, those parts of the digesting materials, that are proper for their purpose, by its stimulus on their mouths. 4. When the stomach and intestines are thus filled with their proper food, not only the motions of the gastric glands, the pancreas, liver, and lacteal vessels, are excited into action; but at the same time the whole tribe of irritative motions are exerted with greater energy, a greater degree of warmth, colour, plumpness, and moisture, is given to the skin from the increased action of those glands called capillary vessels; pleasurable sensation is excited, the voluntary motions are less easily exerted, and at length suspended; and sleep succeeds, unless it be prevented by the stimulus of surrounding objects, or by voluntary exertion, or by an acquired habit, which was originally produced by one or other of these circumstances, as is explained in Sect. XXI. on Drunkenness. At this time also, as the blood-vessels become replete with chyle, more urine is separated into the bladder, and less of it is reabsorbed; more mucus poured into the cellular membranes, and less of it reabsorbed; the pulse becomes fuller, and softer, and in general quicker. The reason why less urine and cellular mucus is absorbed after a full meal with sufficient drink is owing to the blood-vessels being fuller: hence one means to promote absorption is to decrease the resistance by emptying the vessels by venesection. From this decreased absorption the urine becomes pale as well as copious, and the skin appears plump as well as florid. By daily repetition of these movements they all become connected together, and make a diurnal circle of irritative action, and if one of this chain be disturbed, the whole is liable to be put into disorder. See Sect. XX. on Vertigo. 5. When the stomach and intestines receive a quantity of food, whose stimulus is greater than usual, all their motions, and those of the glands and lymphatics, are stimulated into stronger action than usual, and perform their offices with greater vigour and in less time: such are the effects of certain quantities of spice or of vinous spirit. 6. But if the quantity or duration of these stimuli are still further increased, the stomach and throat are stimulated into a motion, whose direction is contrary to the natural one above described; and they regurgitate the materials, which they contain, instead of carrying them forwards. This retrograde motion of the stomach may be compared to the stretchings of wearied limbs the contrary way, and is well elucidated by the following experiment. Look earnestly for a minute or two on an area an inch square of pink silk, placed in a strong light, the eye becomes fatigued, the colour becomes faint, and at length vanishes, for the fatigued eye can no longer be stimulated into direct motions; then on closing the eye a green spectrum will appear in it, which is a colour directly contrary to pink, and which will appear and disappear repeatedly, like the efforts in vomiting. See Section XXIX. 11. Hence all those drugs, which by their bitter or astringent stimulus increase the action of the stomach, as camomile and white vitriol, if their quantity is increased above a certain dose become emetics. These inverted motions of the stomach and throat are generally produced from the stimulus of unnatural food, and are attended with the sensation of nausea or sickness: but as this sensation is again connected with an idea of the distasteful food, which induced it; so an idea of nauseous food will also sometimes excite the action of nausea; and that give rise by association to the inversion of the motions of the stomach and throat. As some, who have had horse-flesh or dogs-flesh given them for beef or mutton, are said to have vomited many hours afterwards, when they have been told of the imposition. I have been told of a person, who had gained a voluntary command over these inverted motions of the stomach and throat, and supported himself by exhibiting this curiosity to the public. At these exhibitions he swallowed a pint of red rough gooseberries, and a pint of white smooth ones, brought them up in small parcels into his mouth, and restored them separately to the spectators, who called for red or white as they pleased, till the whole were redelivered. 7. At the same time that these motions of the stomach and throat are stimulated into inversion, some of the other irritative motions, that had acquired more immediate connexions with the stomach, as those of the gastric glands, are excited into stronger action by this association; and some other of these motions, which are more easily excited, as those of the gastric lymphatics, are inverted by their association with the retrograde motions of the stomach, and regurgitate their contents, and thus a greater quantity of mucus, and of lymph, or chyle, is poured into the stomach, and thrown up along with its contents. 8. These inversions of the motion of the stomach in vomiting are performed by intervals, for the same reason that many other motions are reciprocally exerted and relaxed; for during the time of exertion the stimulus, or sensation, which caused this exertion, is not perceived; but begins to be perceived again, as soon as the exertion ceases, and is some time in again producing its effect. As explained in Sect. XXXIV. on Volition, where it is shewn, that the contractions of the fibres, and the sensation of pain, which occasioned that exertion, cannot exist at the same time. The exertion ceases from another cause also, which is the exhaustion of the sensorial power of the part, and these two causes frequently operate together. 9. At the times of these inverted efforts of the stomach not only the lymphatics, which open their mouths into the stomach, but those of the skin also, are for a time inverted; for sweats are sometimes pushed out during the efforts of vomiting without an increase of heat. 10. But if by a greater stimulus the motions of the stomach are inverted still more violently or more permanently, the duodenum has its peristaltic motions inverted at the same time by their association with those of the stomach; and the bile and pancreatic juice, which it contains, are by the inverted motions brought up into the stomach, and discharged along with its contents; while a greater quantity of bile and pancreatic juice is poured into this intestine; as the glands, that secrete them, are by their association with the motions of the intestine excited into stronger action than usual. 11. The other intestines are by association excited into more powerful action, while the lymphatics, that open their mouths into them, suffer an inversion of their motions corresponding with the lymphatics of the stomach, and duodenum; which with a part of the abundant secretion of bile is carried downwards, and contributes both to stimulate the bowels, and to increase the quantity of the evacuations. This inversion of the motion of the lymphatics appears from the quantity of chyle, which comes away by stools; which is otherwise absorbed as soon as produced, and by the immense quantity of thin fluid, which is evacuated along with it. 12. But if the stimulus, which inverts the stomach, be still more powerful, or more permanent, it sometimes happens, that the motions of the biliary glands, and of their excretory ducts, are at the same time inverted, and regurgitate their contained bile into the blood-vessels, as appears by the yellow colour of the skin, and of the urine; and it is probable the pancreatic secretion may suffer an inversion at the same time, though we have yet no mark by which this can be ascertained. 13. Mr. ---- eat two putrid pigeons out of a cold pigeon-pye, and drank about a pint of beer and ale along with them, and immediately rode about five miles. He was then seized with vomiting, which was after a few periods succeeded by purging; these continued alternately for two hours; and the purging continued by intervals for six or eight hours longer. During this time he could not force himself to drink more than one pint in the whole; this great inability to drink was owing to the nausea, or inverted motions of the stomach, which the voluntary exertion of swallowing could seldom and with difficulty overcome; yet he discharged in the whole at least six quarts; whence came this quantity of liquid? First, the contents of the stomach were emitted, then of the duodenum, gall-bladder, and pancreas, by vomiting. After this the contents of the lower bowels, then the chyle, that was in the lacteal vessels, and in the receptacle of chyle, was regurgitated into the intestines by a retrograde motion of these vessels. And afterwards the mucus deposited in the cellular membrane, and on the surface of all the other membranes, seems to have been absorbed; and with the fluid absorbed from the air to have been carried up their respective lymphatic branches by the increased energy of their natural motions, and down the visceral lymphatics, or lacteals, by the inversion of their motions. 14. It may be difficult to invent experiments to demonstrate the truth of this inversion of some branches of the absorbent system, and increased absorption of others, but the analogy of these vessels to the intestinal canal, and the symptoms of many diseases, render this opinion more probable than many other received opinions of the animal oeconomy. In the above instance, after the yellow excrement was voided, the fluid ceased to have any smell, and appeared like curdled milk, and then a thinner fluid, and some mucus, were evacuated; did not these seem to partake of the chyle, of the mucous fluid from all the cells of the body, and lastly, of the atmospheric moisture? All these facts may be easily observed by any one, who takes a brisk purge. 15. Where the stimulus on the stomach, or on some other part of the intestinal canal, is still more permanent, not only the lacteal vessels, but the whole canal itself, becomes inverted from its associations: this is the iliac passion, in which all the fluids mentioned above are thrown up by the mouth. At this time the valve in the colon, from the inverted motions of that bowel, and the inverted action of this living valve, does not prevent the regurgitation of its contents. The structure of this valve may be represented by a flexile leathern pipe standing up from the bottom of a vessel of water: its sides collapse by the pressure of the ambient fluid, as a small part of that fluid passes through it; but if it has a living power, and by its inverted action keeps itself open, it becomes like a rigid pipe, and will admit the whole liquid to pass. See Sect. XXIX. 2. 5. In this case the patient is averse to drink, from the constant inversion of the motions of the stomach, and yet many quarts are daily ejected from the stomach, which at length smell of excrement, and at last seem to be only a thin mucilaginous or aqueous liquor. From whence is it possible, that this great quantity of fluid for many successive days can be supplied, after the cells of the body have given up their fluids, but from the atmosphere? When the cutaneous branch of absorbents acts with unnatural strength, it is probable the intestinal branch has its motions inverted, and thus a fluid is supplied without entering the arterial system. Could oiling or painting the skin give a check to this disease? So when the stomach has its motions inverted, the lymphatics of the stomach, which are most strictly associated with it, invert their motions at the same time. But the more distant branches of lymphatics, which are less strictly associated with it, act with increased energy; as the cutaneous lymphatics in the cholera, or iliac passion, above described. And other irritative motions become decreased, as the pulsations of the arteries, from the extra-derivation or exhaustion of the sensorial power. Sometimes when stronger vomiting takes place the more distant branches of the lymphatic system invert their motions with those of the stomach, and loose stools are produced, and cold sweats. So when the lacteals have their motions inverted, as during the operation of strong purges, the urinary and cutaneous absorbents have their motions increased to supply the want of fluid in the blood, as in great thirst; but after a meal with sufficient potation the urine is pale, that is, the urinary absorbents act weakly, no supply of water being wanted for the blood. And when the intestinal absorbents act too violently, as when too great quantities of fluid have been drank, the urinary absorbents invert their motions to carry off the superfluity, which is a new circumstance of association, and a temporary diabetes supervenes. 16. I have had the opportunity of seeing four patients in the iliac passion, where the ejected material smelled and looked like excrement. Two of these were so exhausted at the time I saw them, that more blood could not be taken from them, and as their pain had ceased, and they continued to vomit up every thing which they drank, I suspected that a mortification of the bowel had already taken place, and as they were both women advanced in life, and a mortification is produced with less preceding pain in old and weak people, these both died. The other two, who were both young men, had still pain and strength sufficient for further venesection, and they neither of them had any appearance of hernia, both recovered by repeated bleeding, and a scruple of calomel given to one, and half a dram to the other, in very small pills: the usual means of clysters, and purges joined with opiates, had been in vain attempted. I have thought an ounce or two of crude mercury in less violent diseases of this kind has been of use, by contributing to restore its natural motion to some part of the intestinal canal, either by its weight or stimulus; and that hence the whole tube recovered its usual associations of progressive peristaltic motion. I have in three cases seen crude mercury given in small doses, as one or two ounces twice a day, have great effect in stopping pertinacious vomitings. 17. Besides the affections above described, the stomach is liable, like many other membranes of the body, to torpor without consequent inflammation: as happens to the membranes about the head in some cases of hemicrania, or in general head-ach. This torpor of the stomach is attended with indigestion, and consequent flatulency, and with pain, which is usually called the cramp of the stomach, and is relievable by aromatics, essential oils, alcohol, or opium. The intrusion of a gall-stone into the common bile-duct from the gall-bladder is sometimes mistaken for a pain of the stomach, as neither of them are attended with fever; but in the passage of a gall-stone, the pain is confined to a less space, which is exactly where the common bile-duct enters the duodenum, as explained in Section XXX. 1. 3. Whereas in this gastrodynia the pain is diffused over the whole stomach; and, like other diseases from torpor, the pulse is weaker, and the extremities colder, and the general debility greater, than in the passage of a gall-stone; for in the former the debility is the consequence of the pain, in the latter it is the cause of it. Though the first fits of the gout, I believe, commence with a torpor of the liver; and the ball of the toe becomes inflamed instead of the membranes of the liver in consequence of this torpor, as a coryza or catarrh frequently succeeds a long exposure of the feet to cold, as in snow, or on a moist brick-floor; yet in old or exhausted constitutions, which have been long habituated to its attacks, it sometimes commences with a torpor of the stomach, and is transferable to every membrane of the body. When the gout begins with torpor of the stomach, a painful sensation of cold occurs, which the patient compares to ice, with weak pulse, cold extremities, and sickness; this in its slighter degree is relievable by spice, wine, or opium; in its greater degree it is succeeded by sudden death, which is owing to the sympathy of the stomach with the heart, as explained below. If the stomach becomes inflamed in consequence of this gouty torpor of it, or in consequence of its sympathy with some other part, the danger is less. A sickness and vomiting continues many days, or even weeks, the stomach rejecting every thing stimulant, even opium or alcohol, together with much viscid mucus; till the inflammation at length ceases, as happens when other membranes, as those of the joints, are the seat of gouty inflammation; as observed in Sect. XXIV. 2. 8. The sympathy, or association of motions, between those of the stomach and those of the heart, are evinced in many diseases. First, many people are occasionally affected with an intermission of their pulse for a few days, which then ceases again. In this case there is a stop of the motion of the heart, and at the same time a tendency to eructation from the stomach. As soon as the patient feels a tendency to the intermission of the motion of his heart, if he voluntarily brings up wind from his stomach, the stop of the heart does not occur. From hence I conclude that the stop of digestion is the primary disease; and that air is instantly generated from the aliment, which begins to ferment, if the digestive process is impeded for a moment, (see Sect. XXIII. 4.); and that the stop of the heart is in consequence of the association of the motions of these viscera, as explained in Sect. XXXV. 1. 4.; but if the little air, which is instantly generated during the temporary torpor of the stomach, be evacuated, the digestion recommences, and the temporary torpor of the heart does not follow. One patient, whom I lately saw, and who had been five or six days much troubled with this intermission of a pulsation of his heart, and who had hemicrania with some fever, was immediately relieved from them all by losing ten ounces of blood, which had what is termed an inflammatory crust on it. Another instance of this association between the motions of the stomach and heart is evinced by the exhibition of an over dose of foxglove, which induces an incessant vomiting, which is attended with very slow, and sometimes intermitting pulse.--Which continues in spite of the exhibition of wine and opium for two or three days. To the same association must be ascribed the weak pulse, which constantly attends the exhibition of emetics during their operation. And also the sudden deaths, which have been occasioned in boxing by a blow on the stomach; and lastly, the sudden death of those, who have been long debilitated by the gout, from the torpor of the stomach. See Sect. XXXV. 1. 4. * * * * * SECT. XXVI. OF THE CAPILLARY GLANDS AND MEMBRANES. I. 1. _The capillary vessels are glands._ 2. _Their excretory ducts. Experiments on the mucus of the intestines, abdomen, cellular membrane, and on the humours of the eye._ 3. _Scurf on the head, cough, catarrh, diarrhoea, gonorrhoea._ 4. _Rheumatism. Gout. Leprosy._ II. 1. _The most minute membranes are unorganized._ 2. _Larger membranes are composed of the ducts of the capillaries, and the mouths of the absorbents._ 3. _Mucilaginous fluid is secreted on their surfaces._ III. _Three kinds of rheumatism._ I. 1. The capillary-vessels are like all the other glands except the absorbent system, inasmuch as they receive blood from the arteries, separate a fluid from it, and return the remainder by the veins. 2. This series of glands is of the most extensive use, as their excretory ducts open on the whole external skin forming its perspirative pores, and on the internal surfaces of every cavity of the body. Their secretion on the skin is termed insensible perspiration, which in health is in part reabsorbed by the mouths of the lymphatics, and in part evaporated in the air; the secretion on the membranes, which line the larger cavities of the body, which have external openings, as the mouth and intestinal canal, is termed mucus, but is not however coagulable by heat; and the secretion on the membranes of those cavities of the body, which have no external openings, is called lymph or water, as in the cavities of the cellular membrane, and of the abdomen; this lymph however is coagulable by the heat of boiling water. Some mucus nearly as viscid as the white of egg, which was discharged by stool, did not coagulate, though I evaporated it to one fourth of the quantity, nor did the aqueous and vitreous humours of a sheep's eye coagulate by the like experiment: but the serosity from an anasarcous leg, and that from the abdomen of a dropsical person, and the crystalline humour of a sheep's eye, coagulated in the same heat. 3. When any of these capillary glands are stimulated into greater irritative actions, than is natural, they secrete a more copious material; and as the mouths of the absorbent system, which open in their vicinity, are at the same time stimulated into greater action, the thinner and more saline part of the secreted fluid is taken up again; and the remainder is not only more copious but also more viscid than natural. This is more or less troublesome or noxious according to the importance of the functions of the part affected: on the skin and bronchiæ, where this secretion ought naturally to evaporate, it becomes so viscid as to adhere to the membrane; on the tongue it forms a pellicle, which can with difficulty be scraped off; produces the scurf on the heads of many people; and the mucus, which is spit up by others in coughing. On the nostrils and fauces, when the secretion of these capillary glands is increased, it is termed simple catarrh; when in the intestines, a mucous diarrhoea; and in the urethra, or vagina, it has the name of gonorrhoea, or fluor albus. 4. When these capillary glands become inflamed, a still more viscid or even cretaceous humour is produced upon the surfaces of the membranes, which is the cause or the effect of rheumatism, gout, leprosy, and of hard tumours of the legs, which are generally termed scorbutic; all which will be treated of hereafter. II. 1. The whole surface of the body, with all its cavities and contents, are covered with membrane. It lines every vessel, forms every cell, and binds together all the muscular and perhaps the osseous fibres of the body; and is itself therefore probably a simpler substance than those fibres. And as the containing vessels of the body from the largest to the least are thus lined and connected with membranes, it follows that these membranes themselves consisted of unorganized materials. For however small we may conceive the diameters of the minutest vessels of the body, which escape our eyes and glasses, yet these vessels must consist of coats or sides, which are made up of an unorganized material, and which are probably produced from a gluten, which hardens after its production, like the silk or web of caterpillars and spiders. Of this material consist the membranes, which line the shells of eggs, and the shell itself, both which are unorganized, and are formed from mucus, which hardens after it is formed, either by the absorption of its more fluid part, or by its uniting with some part of the atmosphere. Such is also the production of the shells of snails, and of shell-fish, and I suppose of the enamel of the teeth. 2. But though the membranes, that compose the sides of the most minute vessels, are in truth unorganized materials, yet the larger membranes, which are perceptible to the eye, seem to be composed of an intertexture of the mouths of the absorbent system, and of the excretory ducts of the capillaries, with their concomitant arteries, veins, and nerves: and from this construction it is evident, that these membranes must possess great irritability to peculiar stimuli, though they are incapable of any motions, that are visible to the naked eye: and daily experience shews us, that in their inflamed state they have the greatest sensibility to pain, as in the pleurisy and paronychia. 3. On all these membranes a mucilaginous or aqueous fluid is secreted, which moistens and lubricates their surfaces, as was explained in Section XXIII. 2. Some have doubted, whether this mucus is separated from the blood by an appropriated set of glands, or exudes through the membranes, or is an abrasion or destruction of the surface of the membrane itself, which is continually repaired on the other side of it, but the great analogy between the capillary vessels, and the other glands, countenances the former opinion; and evinces, that these capillaries are the glands, that secrete it; to which we must add, that the blood in passing these capillary vessels undergoes a change in its colour from florid to purple, and gives out a quantity of heat; from whence, as in other glands, we must conclude that something is secreted from it. III. The seat of rheumatism is in the membranes, or upon them; but there are three very distinct diseases, which commonly are confounded under this name. First, when a membrane becomes affected with torpor, or inactivity of the vessels which compose it, pain and coldness succeed, as in the hemicrania, and other head-achs, which are generally termed nervous rheumatism; they exist whether the part be at rest or in motion, and are generally attended with other marks of debility. Another rheumatism is said to exist, when inflammation and swelling, as well as pain, affect some of the membranes of the joints, as of the ancles, wrists, knees, elbows, and sometimes of the ribs. This is accompanied with fever, is analogous to pleurisy and other inflammations, and is termed the acute rheumatism. A third disease is called chronic rheumatism, which is distinguished from that first mentioned, as in this the pain only affects the patient during the motion of the part, and from the second kind of rheumatism above described, as it is not attended with quick pulse or inflammation. It is generally believed to succeed the acute rheumatism of the same part, and that some coagulable lymph, or cretaceous, or calculous material, has been left on the membrane; which gives pain, when the muscles move over it, as some extraneous body would do, which was too insoluble to be absorbed. Hence there is an analogy between this chronic rheumatism and the diseases which produce gravel or gout-stones; and it may perhaps receive relief from the same remedies, such as aerated sal soda. * * * * * SECT. XXVII. OF HÆMORRHAGES. I. _The veins are absorbent vessels._ 1. _Hæmorrhages from inflammation. Case of hæmorrhage from the kidney cured by cold bathing. Case of hæmorrhage from the nose cured by cold immersion._ II. _Hæmorrhage from venous paralysis. Of Piles. Black stools. Petechiæ. Consumption. Scurvy of the lungs. Blackness of the face and eyes in epileptic fits. Cure of hæmorrhages from venous inability._ I. As the imbibing mouths of the absorbent system already described open on the surface, and into the larger cavities of the body, so there is another system of absorbent vessels, which are not commonly esteemed such, I mean the veins, which take up the blood from the various glands and capillaries, after their proper fluids or secretions have been separated from it. The veins resemble the other absorbent vessels; as the progression of their contents is carried on in the same manner in both, they alike absorb their appropriated fluids, and have valves to prevent its regurgitation by the accidents of mechanical violence. This appears first, because there is no pulsation in the very beginnings of the veins, as is seen by microscopes; which must happen, if the blood was carried into them by the actions of the arteries. For though the concurrence of various venous streams of blood from different distances must prevent any pulsation in the larger branches, yet in the very beginnings of all these branches a pulsation must unavoidably exist, if the circulation in them was owing to the intermitted force of the arteries. Secondly, the venous absorption of blood from the penis, and from the teats of female animals after their erection, is still more similar to the lymphatic absorption, as it is previously poured into cells, where all arterial impulse must cease. There is an experiment, which seems to evince this venous absorption, which consists in the external application of a stimulus to the lips, as of vinegar, by which they become instantly pale; that is, the bibulous mouths of the veins by this stimulus are excited to absorb the blood faster, than it can be supplied by the usual arterial exertion. See Sect. XXIII. 5. There are two kinds of hæmorrhages frequent in diseases, one is where the glandular or capillary action is too powerfully exerted, and propels the blood forwards more hastily, than the veins can absorb it; and the other is, where the absorbent power of the veins is diminished, or a branch of them is become totally paralytic. 1. The former of these cases is known by the heat of the part, and the general fever or inflammation that accompanies the hæmorrhage. An hæmorrhage from the nose or from the lungs is sometimes a crisis of inflammatory diseases, as of the hepatitis and gout, and generally ceases spontaneously, when the vessels are considerably emptied. Sometimes the hæmorrhage recurs by daily periods accompanying the hot fits of fever, and ceasing in the cold fits, or in the intermissions; this is to be cured by removing the febrile paroxysms, which will be treated of in their place. Otherwise it is cured by venesection, by the internal or external preparations of lead, or by the application of cold, with an abstemious diet, and diluting liquids, like other inflammations. Which by inducing a quiescence on those glandular parts, that are affected, prevents a greater quantity of blood from being protruded forwards, than the veins are capable of absorbing. Mr. B---- had an hæmorrhage from his kidney, and parted with not less than a pint of blood a day (by conjecture) along with his urine for above a fortnight: venesections, mucilages, balsams, preparations of lead, the bark, alum, and dragon's blood, opiates, with a large blister on his loins, were separately tried, in large doses, to no purpose. He was then directed to bathe in a cold spring up to the middle of his body only, the upper part being covered, and the hæmorrhage diminished at the first, and ceased at the second immersion. In this case the external capillaries were rendered quiescent by the coldness of the water, and thence a less quantity of blood was circulated through them; and the internal capillaries, or other glands, became quiescent from their irritative associations with the external ones; and the hæmorrhage was stopped a sufficient time for the ruptured vessels to contract their apertures, or for the blood in those apertures to coagulate. Mrs. K---- had a continued haemorrhage from her nose for some days; the ruptured vessel was not to be reached by plugs up the nostrils, and the sensibility of her fauces was such that nothing could be born behind the uvula. After repeated venesection, and other common applications, she was directed to immerse her whole head into a pail of water, which was made colder by the addition of several handfuls of salt, and the hæmorrhage immediately ceased, and returned no more; but her pulse continued hard, and she was necessitated to lose blood from the arm on the succeeding day. Query, might not the cold bath instantly stop hæmorrhages from the lungs in inflammatory cases?--for the shortness of breath of those, who go suddenly into cold water, is not owing to the accumulation of blood in the lungs, but to the quiescence of the pulmonary capillaries from association, as explained in Section XXXII. 3. 2. II. The other kind of hæmorrhage is known from its being attended with a weak pulse, and other symptoms of general debility, and very frequently occurs in those, who have diseased livers, owing to intemperance in the use of fermented liquors. These constitutions are shewn to be liable to paralysis of the lymphatic absorbents, producing the various kinds of dropsies in Section XXIX. 5. Now if any branch of the venous system loses its power of absorption, the part swells, and at length bursts and discharges the blood, which the capillaries or other glands circulate through them. It sometimes happens that the large external veins of the legs burst, and effuse their blood; but this occurs most frequently in the veins of the intestines, as the vena portarum is liable to suffer from a schirrus of the liver opposing the progression of the blood, which is absorbed from the intestines. Hence the piles are a symptom of hepatic obstruction, and hence the copious discharges downwards or upwards of a black material, which has been called melancholia, or black bile; but is no other than the blood, which is probably discharged from the veins of the intestines. J.F. Meckel, in his Experimenta de Finibus Vasorum, published at Berlin, 1772, mentions his discovery of a communication of a lymphatic vessel with the gastric branch of the vena portarum. It is possible, that when the motion of the lymphatic becomes retrograde in some diseases, that blood may obtain a passage into it, where it anastomoses with the vein, and thus be poured into the intestines. A discharge of blood with the urine sometimes attends diabetes, and may have its source in the same manner. Mr. A----, who had been a hard drinker, and had the gutta rosacea on his face and breast, after a stroke of the palsy voided near a quart of a black viscid material by stool: on diluting it with water it did not become yellow, as it must have done if it had been inspissated bile, but continued black like the grounds of coffee. But any other part of the venous system may become quiescent or totally paralytic as well as the veins of the intestines: all which occur more frequently in those who have diseased livers, than in any others. Hence troublesome bleedings of the nose, or from the lungs with a weak pulse; hence hæmorrhages from the kidneys, too great menstruation; and hence the oozing of blood from every part of the body, and the petechiæ in those fevers, which are termed putrid, and which is erroneously ascribed to the thinness of the blood: for the blood in inflammatory diseases is equally fluid before it coagulates in the cold air. Is not that hereditary consumption, which occurs chiefly in dark-eyed people about the age of twenty, and commences with slight pulmonary hæmorrhages without fever, a disease of this kind?--These hæmorrhages frequently begin during sleep, when the irritability of the lungs is not sufficient in these patients to carry on the circulation without the assistance of volition; for in our waking hours, the motions of the lungs are in part voluntary, especially if any difficulty of breathing renders the efforts of volition necessary. See Class I. 2. 1. 3. and Class III. 2. 1. 12. Another species of pulmonary consumption which seems more certainly of scrophulous origin is described in the next Section, No. 2. I have seen two cases of women, of about forty years of age, both of whom were seized with quick weak pulse, with difficult respiration, and who spit up by coughing much viscid mucus mixed with dark coloured blood. They had both large vibices on their limbs, and petechiæ; in one the feet were in danger of mortification, in the other the legs were oedematous. To relieve the difficult respiration, about six ounces of blood were taken from one of them, which to my surprise was sizy, like inflamed blood: they had both palpitations or unequal pulsations of the heart. They continued four or five weeks with pale and bloated countenances, and did not cease spitting phlegm mixed with black blood, and the pulse seldom slower than 130 or 135 in a minute. This blood, from its dark colour, and from the many vibices and petechiæ, seems to have been venous blood; the quickness of the pulse, and the irregularity of the motion of the heart, are to be ascribed to debility of that part of the system; as the extravasation of blood originated from the defect of venous absorption. The approximation of these two cases to sea-scurvy is peculiar, and may allow them to be called scorbutus pulmonalis. Had these been younger subjects, and the paralysis of the veins had only affected the lungs, it is probable the disease would have been a pulmonary consumption. Last week I saw a gentleman of Birmingham, who had for ten days laboured under great palpitation of his heart, which was so distinctly felt by the hand, as to discountenance the idea of there being a fluid in the pericardium. He frequently spit up mucus stained with dark coloured blood, his pulse very unequal and very weak, with cold hands and nose. He could not lie down at all, and for about ten days past could not sleep a minute together, but waked perpetually with great uneasiness. Could those symptoms be owing to very extensive adhesions of the lungs? or is this a scorbutus pulmonalis? After a few days he suddenly got so much better as to be able to sleep many hours at a time by the use of one grain of powder of foxglove twice a day, and a grain of opium at night. After a few days longer, the bark was exhibited, and the opium continued with some wine; and the palpitations of his heart became much relieved, and he recovered his usual degree of health, but died suddenly some months afterwards. In epileptic fits the patients frequently become black in the face, from the temporary paralysis of the venous system of this part. I have known two instances where the blackness has continued many days. M. P----, who had drank intemperately, was seized with the epilepsy when he was in his fortieth year; in one of these fits the white part of his eyes was left totally black with effused blood; which was attended with no pain or heat, and was in a few weeks gradually absorbed, changing colour as is usual with vibices from bruises. The hæmorrhages produced from the inability of the veins to absorb the refluent blood, is cured by opium, the preparations of steel, lead, the bark, vitriolic acid, and blisters; but these have the effect with much more certainty, if a venesection to a few ounces, and a moderate cathartic with four or six grains of calomel be premised, where the patient is not already too much debilitated; as one great means of promoting the absorption of any fluid consists in previously emptying the vessels, which are to receive it. * * * * * SECT. XXVIII. OF THE PARALYSIS OF THE ABSORBENT SYSTEM. I. _Paralysis of the lacteals, atrophy. Distaste to animal food._ II. _Cause of dropsy. Cause of herpes. Scrophula. Mesenteric consumption. Pulmonary consumption. Why ulcers in the lungs are so difficult to heal._ The term paralysis has generally been used to express the loss of voluntary motion, as in the hemiplagia, but may with equal propriety be applied to express the disobediency of the muscular fibres to the other kinds of stimulus; as to those of irritation or sensation. I. There is a species of atrophy, which has not been well understood; when the absorbent vessels of the stomach and intestines have been long inured to the stimulus of too much spirituous liquor, they at length, either by the too sudden omission of fermented or spirituous potation, or from the gradual decay of nature, become in a certain degree paralytic; now it is observed in the larger muscles of the body, when one side is paralytic, the other is more frequently in motion, owing to the less expenditure of sensorial power in the paralytic limbs; so in this case the other part of the absorbent system acts with greater force, or with greater perseverance, in consequence of the paralysis of the lacteals; and the body becomes greatly emaciated in a small time. I have seen several patients in this disease, of which the following are the circumstances. 1. They were men about fifty years of age, and had lived freely in respect to fermented liquors. 2. They lost their appetite to animal food. 3. They became suddenly emaciated to a great degree. 4. Their skins were dry and rough. 5. They coughed and expectorated with difficulty a viscid phlegm. 6. The membrane of the tongue was dry and red, and liable to become ulcerous. The inability to digest animal food, and the consequent distaste to it, generally precedes the dropsy, and other diseases, which originate from spirituous potation. I suppose when the stomach becomes inirritable, that there is at the same time a deficiency of gastric acid; hence milk seldom agrees with these patients, unless it be previously curdled, as they have not sufficient gastric acid to curdle it; and hence vegetable food, which is itself acescent, will agree with their stomachs longer than animal food, which requires more of the gastric acid for its digestion. In this disease the skin is dry from the increased absorption of the cutaneous lymphatics, the fat is absorbed from the increased absorption of the cellular lymphatics, the mucus of the lungs is too viscid to be easily spit up by the increased absorption of the thinner parts of it, the membrana sneideriana becomes dry, covered with hardened mucus, and at length becomes inflamed and full of aphthæ, and either these sloughs, or pulmonary ulcers, terminate the scene. II. The immediate cause of dropsy is the paralysis of some other branches of the absorbent system, which are called lymphatics, and which open into the larger cavities of the body, or into the cells of the cellular membrane; whence those cavities or cells become distended with the fluid, which is hourly secreted into them for the purpose of lubricating their surfaces. As is more fully explained in No. 5. of the next Section. As those lymphatic vessels consist generally of a long neck or mouth, which drinks up its appropriated fluid, and of a conglobate gland, in which this fluid undergoes some change, it happens, that sometimes the mouth of the lymphatic, and sometimes the belly or glandular part of it, becomes totally or partially paralytic. In the former case, where the mouths of the cutaneous lymphatics become torpid or quiescent, the fluid secreted on the skin ceases to be absorbed, and erodes the skin by its saline acrimony, and produces eruptions termed herpes, the discharge from which is as salt, as the tears, which are secreted too fast to be reabsorbed, as in grief, or when the puncta lacrymalia are obstructed, and which running down the cheek redden and inflame the skin. When the mouths of the lymphatics, which open on the mucous membrane of the nostrils, become torpid, as on walking into the air in a frosty morning; the mucus, which continues to be secreted, has not its aqueous and saline part reabsorbed, which running over the upper lip inflames it, and has a salt taste, if it falls on the tongue. When the belly, or glandular part of these lymphatics, becomes torpid, the fluid absorbed by its mouth stagnates, and forms a tumour in the gland. This disease is called the scrophula. If these glands suppurate externally, they gradually heal, as those of the neck; if they suppurate without an opening on the external habit, as the mesenteric glands, a hectic fever ensues, which destroys the patient; if they suppurate in the lungs, a pulmonary consumption ensues, which is believed thus to differ from that described in the preceding Section, in respect to its seat or proximate cause. It is remarkable, that matter produced by suppuration will lie concealed in the body many weeks, or even months, without producing hectic fever; but as soon as the wound is opened, so as to admit air to the surface of the ulcer, a hectic fever supervenes, even in very few hours, which is probably owing to the azotic part of the atmosphere rather than to the oxygene; because those medicines, which contain much oxygene, as the calces or oxydes of metals, externally applied, greatly contribute to heal ulcers, of these are the solutions of lead and mercury, and copper in acids, or their precipitates. Hence when wounds are to be healed by the first intention, as it is called, it is necessary carefully to exclude the air from them. Hence we have one cause, which prevents pulmonary ulcers from healing, which is their being perpetually exposed to the air. Both the dark-eyed patients, which are affected with pulmonary ulcers from deficient venous absorption, as described in Section. XXVII. 2. and the light-eyed patients from deficient lymphatic absorption, which we are now treating of, have generally large apertures of the iris; these large pupils of the eyes are a common mark of want of irritability; and it generally happens, that an increase of sensibility, that is, of motions in consequence of sensation, attends these constitutions. See Sect. XXXI. 2. Whence inflammations may occur in these from stagnated fluids more frequently than in those constitutions, which possess more irritability and less sensibility. Great expectations in respect to the cure of consumptions, as well as of many other diseases, are produced by the very ingenious exertions of DR. BEDDOES; who has established an apparatus for breathing various mixtures of airs or gasses, at the hot-wells near Bristol, which well deserves the attention of the public. DR. BEDDOES very ingeniously concludes, from the florid colour of the blood of consumptive patients, that it abounds in oxygene; and that the redness of their tongues, and lips, and the fine blush of their cheeks shew the presence of the same principle, like flesh reddened by nitre. And adds, that the circumstance of the consumptions of pregnant women being stopped in their progress during pregnancy, at which time their blood may be supposed to be in part deprived of its oxygene, by oxygenating the blood of the foetus, is a forceable argument in favour of this theory; which must soon be confirmed or confuted by his experiments. See Essay on Scurvy, Consumption, &c. by Dr. Beddoes. Murray. London. Also Letter to Dr. Darwin, by the same. Murray. London. * * * * * SECT. XXIX. ON THE RETROGRADE MOTIONS OF THE ABSORBENT SYSTEM. I. _Account of the absorbent system._ II. _The valves of the absorbent vessels may suffer their fluids to regurgitate in some diseases._ III. _Communication from the alimentary canal to the bladder by means of the absorbent vessels._ IV. _The phenomena of diabetes explained._ V. 1. _The phenomena of dropsies explained._ 2. _Cases of the use of foxglove._ VI. _Of cold sweats._ VII. _Translations of matter, of chyle, of milk, of urine, operation of purging drugs applied externally._ VIII. _Circumstances by which the fluids, that are effused by the retrograde motions of the absorbent vessels, are distinguished._ IX. _Retrograde motions of vegetable juices._ X. _Objections answered._ XI. _The causes, which induce the retrograde motions of animal vessels, and the medicines by which the natural motions are restored._ _N.B. The following Section is a translation of a part of a Latin thesis written by the late Mr. Charles Darwin, which was printed with his prize-dissertation on a criterion between matter and mucus in 1780. Sold by Cadell, London._ I. _Account of the Absorbent System._ 1. The absorbent system of vessels in animal bodies consists of several branches, differing in respect to their situations, and to the fluids, which they absorb. The intestinal absorbents open their mouths on the internal surfaces of the intestines; their office is to drink up the chyle and the other fluids from the alimentary canal; and they are termed lacteals, to distinguish them from the other absorbent vessels, which have been termed lymphatics. Those, whose mouths are dispersed on the external skin, imbibe a great quantity of water from the atmosphere, and a part of the perspirable matter, which does not evaporate, and are termed cutaneous absorbents. Those, which arise from the internal surface of the bronchia, and which imbibe moisture from the atmosphere, and a part of the bronchial mucus, are called pulmonary absorbents. Those, which open their innumerable mouths into the cells of the whole cellular membrane; and whose use is to take up the fluid, which is poured into those cells, after it has done its office there; may be called cellular absorbents. Those, which arise from the internal surfaces of the membranes, which line the larger cavities of the body, as the thorax, abdomen, scrotum, pericardium, take up the mucus poured into those cavities; and are distinguished by the names of their respective cavities. Whilst those, which arise from the internal surfaces of the urinary bladder, gall-bladder, salivary ducts, or other receptacles of secreted fluids, may take their names from those fluids; the thinner parts of which it is their office to absorb: as urinary, bilious, or salivary absorbents. 2. Many of these absorbent vessels, both lacteals and lymphatics, like some of the veins, are replete with valves: which seem designed to assist the progress of their fluids, or at least to prevent their regurgitation; where they are subjected to the intermitted pressure of the muscular, or arterial actions in their neighbourhood. These valves do not however appear to be necessary to all the absorbents, any more than to all the veins; since they are not found to exist in the absorbent system of fish; according to the discoveries of the ingenious, and much lamented Mr. Hewson. Philos. Trans. v. 59, Enquiries into the Lymph. Syst. p. 94. 3. These absorbent vessels are also furnished with glands, which are called conglobate glands; whose use is not at present sufficiently investigated; but it is probable that they resemble the conglomerate glands both in structure and in use, except that their absorbent mouths are for the conveniency of situation placed at a greater distance from the body of the gland. The conglomerate glands open their mouths immediately into the sanguiferous vessels, which bring the blood, from whence they absorb their respective fluids, quite up to the gland: but these conglobate glands collect their adapted fluids from very distant membranes, or cysts, by means of mouths furnished with long necks for this purpose; and which are called lacteals, or lymphatics. 4. The fluids, thus collected from various parts of the body, pass by means of the thoracic duct into the left subclavian near the jugular vein; except indeed that those collected from the right side of the head and neck, and from the right arm, are carried into the right subclavian vein: and sometimes even the lymphatics from the right side of the lungs are inserted into the right subclavian vein; whilst those of the left side of the head open but just into the summit of the thoracic duct. 5. In the absorbent system there are many anastomoses of the vessels, which seem of great consequence to the preservation of health. These anastomoses are discovered by dissection to be very frequent between the intestinal and urinary lymphatics, as mentioned by Mr. Hewson, (Phil. Trans. v. 58.) 6. Nor do all the intestinal absorbents seem to terminate in the thoracic duct, as appears from some curious experiments of D. Munro, who gave madder to some animals, having previously put a ligature on the thoracic duct, and found their bones, and the serum of their blood, coloured red. II. _The Valves of the Absorbent System may suffer their Fluids to regurgitate in some Diseases._ 1. The many valves, which occur in the progress of the lymphatic and lacteal vessels, would seem insuperable obstacles to the regurgitation of their contents. But as these valves are placed in vessels, which are indued with life, and are themselves indued with life also; and are very irritable into those natural motions, which absorb, or propel the fluids they contain; it is possible, in some diseases, where these valves or vessels are stimulated into unnatural exertions, or are become paralytic, that during the diastole of the part of the vessel to which the valve is attached, the valve may not so completely close, as to prevent the relapse of the lymph or chyle. This is rendered more probable, by the experiments of injecting mercury, or water, or suet, or by blowing air down these vessels: all which pass the valves very easily, contrary to the natural course of their fluids, when the vessels are thus a little forcibly dilated, as mentioned by Dr. Haller, Elem. Physiol. t. iii. s. 4. "The valves of the thoracic duct are few, some assert they are not more than twelve, and that they do not very accurately perform their office, as they do not close the whole area of the duct, and thence may permit chyle to repass them downwards. In living animals, however, though not always, yet more frequently than in the dead, they prevent the chyle from returning. The principal of these valves is that, which presides over the insertion of the thoracic duct, into the subclavian vein; many have believed this also to perform the office of a valve, both to admit the chyle into the vein, and to preclude the blood from entering the duct; but in my opinion it is scarcely sufficient for this purpose." Haller, Elem. Phys. t. vii. p. 226. 2. The mouths of the lymphatics seem to admit water to pass through them after death, the inverted way, easier than the natural one; since an inverted bladder readily lets out the water with which it is filled; whence it may be inferred, that there is no obstacle at the mouths of these vessels to prevent the regurgitation of their contained fluids. I was induced to repeat this experiment, and having accurately tied the ureters and neck of a fresh ox's bladder, I made an opening at the fundus of it; and then, having turned it inside outwards, filled it half full with water, and was surprised to see it empty itself so hastily. I thought the experiment more apposite to my purpose by suspending the bladder with its neck downwards, as the lymphatics are chiefly spread upon this part of it, as shewn by Dr. Watson, Philos. Trans. v. 59. p. 392. 3. In some diseases, as in the diabetes and scrophula, it is probable the valves themselves are diseased, and are thence incapable of preventing the return of the fluids they should support. Thus the valves of the aorta itself have frequently been found schirrous, according to the dissections of Mons. Lieutaud, and have given rise to an interrupted pulse, and laborious palpitations, by suffering a return of part of the blood into the heart. Nor are any parts of the body so liable to schirrosity as the lymphatic glands and vessels, insomuch that their schirrosities have acquired a distinct name, and been termed scrophula. 4. There are valves in other parts of the body, analogous to those of the absorbent system, and which are liable, when diseased, to regurgitate their contents: thus the upper and lower orifices of the stomach are closed by valves, which, when too great quantities of warm water have been drank with a design to promote vomiting, have sometimes resisted the utmost efforts of the abdominal muscles, and diaphragm: yet, at other times, the upper valve, or cardia, easily permits the evacuation of the contents of the stomach; whilst the inferior valve, or pylorus, permits the bile, and other contents of the duodenum, to regurgitate into the stomach. 5. The valve of the colon is well adapted to prevent the retrograde motion of the excrements; yet, as this valve is possessed of a living power, in the iliac passion, either from spasm, or other unnatural exertions, it keeps itself open, and either suffers or promotes the retrograde movements of the contents of the intestines below; as in ruminating animals the mouth of the first stomach seems to be so constructed, as to facilitate or assist the regurgitation of the food; the rings of the oesophagus afterwards contracting themselves in inverted order. De Haeu, by means of a syringe, forced so much water into the rectum intestinum of a dog, that he vomited it in a full stream from his mouth; and in the iliac passion above mentioned, excrements and clyster are often evacuated by the mouth. See Section XXV. 15. 6. The puncta lacrymalia, with the lacrymal sack and nasal duct, compose a complete gland, and much resemble the intestinal canal: the puncta lacrymalia are absorbent mouths, that take up the tears from the eye, when they have done their office there, and convey them into the nostrils; but when the nasal duct is obstructed, and the lacrymal sack distended with its fluid, on pressure with the finger the mouths of this gland (puncta lacrymalia) will readily disgorge the fluid, they had previously absorbed, back into the eye. 7. As the capillary vessels receive blood from the arteries, and separating the mucus, or perspirable matter from it, convey the remainder back by the veins; these capillary vessels are a set of glands, in every respect similar to the secretory vessels of the liver, or other large congeries of glands. The beginnings of these capillary vessels have frequent anastomoses into each other, in which circumstance they are resembled by the lacteals; and like the mouths or beginnings of other glands, they are a set of absorbent vessels, which drink up the blood which is brought to them by the arteries, as the chyle is drank up by the lacteals: for the circulation of the blood through the capillaries is proved to be independent of arterial impulse; since in the blush of shame, and in partial inflammations, their action is increased, without any increase of the motion of the heart. 8. Yet not only the mouths, or beginnings of these anastomosing capillaries are frequently seen by microscopes, to regurgitate some particles of blood, during the struggles of the animal; but retrograde motion of the blood, in the veins of those animals, from the very heart of the extremity of the limbs, is observable, by intervals, during the distresses of the dying creature. Haller, Elem. Physiol. t. i. p. 216. Now, as the veins have perhaps all of them a valve somewhere between their extremities and the heart, here is ocular demonstration of the fluids in this diseased condition of the animal, repassing through venous valves: and it is hence highly probable, from the strictest analogy, that if the course of the fluids, in the lymphatic vessels, could be subjected to microscopic observation, they would also, in the diseased state of the animal, be seen to repass the valves, and the mouths of those vessels, which had previously absorbed them, or promoted their progression. III. _Communication from the Alimentary Canal to the Bladder, by means of the Absorbent Vessels._ Many medical philosophers, both ancient and modern, have suspected that there was a nearer communication between the stomach and the urinary bladder, than that of the circulation: they were led into this opinion from the great expedition with which cold water, when drank to excess, passes off by the bladder; and from the similarity of the urine, when produced in this hasty manner, with the material that was drank. The former of these circumstances happens perpetually to those who drink abundance of cold water, when they are much heated by exercise, and to many at the beginning of intoxication. Of the latter, many instances are recorded by Etmuller, t. xi. p. 716. where simple water, wine, and wine with sugar, and emulsions, were returned by urine unchanged. There are other experiments, that seem to demonstrate the existence of another passage to the bladder, besides that through the kidneys. Thus Dr. Kratzenstein put ligatures on the ureters of a dog, and then emptied the bladder by a catheter; yet in a little time the dog drank greedily, and made a quantity of water, (Disputat. Morbor. Halleri. t. iv. p. 63.) A similar experiment is related in the Philosophical Transactions, with the same event, (No. 65, 67, for the year 1670.) Add to this, that in some morbid cases the urine has continued to pass, after the suppuration or total destruction of the kidneys; of which many instances are referred to in the Elem. Physiol. t. vii. p. 379. of Dr. Haller. From all which it must be concluded, that some fluids have passed from the stomach or abdomen, without having gone through the sanguiferous circulation: and as the bladder is supplied with many lymphatics, as described by Dr. Watson, in the Philos. Trans. v. 59. p. 392. and as no other vessels open into it besides these and the ureters, it seems evident, that the unnatural urine, produced as above described, when the ureters were tied, or the kidneys obliterated, was carried into the bladder by the retrograde motions of the urinary branch of the lymphatic system. The more certainly to ascertain the existence of another communication between the stomach and bladder, besides that of the circulation, the following experiment was made, to which I must beg your patient attention:--A friend of mine (June 14, 1772) on drinking repeatedly of cold small punch, till he began to be intoxicated, made a quantity of colourless urine. He then drank about two drams of nitre dissolved in some of the punch, and eat about twenty stalks of boiled asparagus: on continuing to drink more of the punch, the next urine that he made was quite clear, and without smell; but in a little time another quantity was made, which was not quite so colourless, and had a strong smell of the asparagus: he then lost about four ounces of blood from the arm. The smell of asparagus was not at all perceptible in the blood, neither when fresh taken, nor the next morning, as myself and two others accurately attended to; yet this smell was strongly perceived in the urine, which was made just before the blood was taken from his arm. Some bibulous paper, moistened in the serum of this blood, and suffered to dry, shewed no signs of nitre by its manner of burning. But some of the same paper, moistened in the urine, and dried, on being ignited, evidently shewed the presence of nitre. This blood and the urine stood some days exposed to the sun in the open air, till they were evaporated to about a fourth of their original quantity, and began to stink: the paper, which was then moistened with the concentrated urine, shewed the presence of much nitre by its manner of burning; whilst that moistened with the blood shewed no such appearance at all. Hence it appears, that certain fluids at the beginning of intoxication, find another passage to the bladder besides the long course of the arterial circulation; and as the intestinal absorbents are joined with the urinary lymphatics by frequent anastomoses, as Hewson has demonstrated; and as there is no other road, we may justly conclude, that these fluids pass into the bladder by the urinary branch of the lymphatics, which has its motions inverted during the diseased state of the animal. A gentleman, who had been some weeks affected with jaundice, and whose urine was in consequence of a very deep yellow, took some cold small punch, in which was dissolved about a dram of nitre; he then took repeated draughts of the punch, and kept himself in a cool room, till on the approach of slight intoxication he made a large quantity of water; this water had a slight yellow tinge, as might be expected from a small admixture of bile secreted from the kidneys; but if the whole of it had passed through the sanguiferous vessels, which were now replete with bile (his whole skin being as yellow as gold) would not this urine also, as well as that he had made for weeks before, have been of a deep yellow? Paper dipped in this water, and dryed, and ignited, shewed evident marks of the presence of nitre, when the flame was blown out. IV. _The Phænomena of the Diabetes explained, and of some Diarrhoeas._ The phenomena of many diseases are only explicable from the retrograde motions of some of the branches of the lymphatic system; as the great and immediate flow of pale urine in the beginning of drunkenness; in hysteric paroxysms; from being exposed to cold air; or to the influence of fear or anxiety. Before we endeavour to illustrate this doctrine, by describing the phænomena of these diseases, we must premise one circumstance; that all the branches of the lymphatic system have a certain sympathy with each other, insomuch that when one branch is stimulated into unusual kinds or quantities of motion, some other branch has its motions either increased, or decreased, or inverted at the same time. This kind of sympathy can only be proved by the concurrent testimony of numerous facts, which will be related in the course of the work. I shall only add here, that it is probable, that this sympathy does not depend on any communication of nervous filaments, but on habit; owing to the various branches of this system having frequently been stimulated into action at the same time. There are a thousand instances of involuntary motions associated in this manner; as in the act of vomiting, while the motions of the stomach and oesophagus are inverted, the pulsations of the arterial system by a certain sympathy become weaker; and when the bowels or kidneys are stimulated by poison, a stone, or inflammation, into more violent action; the stomach and oesophagus by sympathy invert their motions. 1. When any one drinks a moderate quantity of vinous spirit, the whole system acts with more energy by consent with the stomach and intestines, as is seen from the glow on the skin, and the increase of strength and activity; but when a greater quantity of this inebriating material is drank, at the same time that the lacteals are excited into greater action to absorb it; it frequently happens, that the urinary branch of absorbents, which is connected with the lacteals by many anastomoses, inverts its motions, and a great quantity of pale unanimalized urine is discharged. By this wise contrivance too much of an unnecessary fluid is prevented from entering the circulation--This may be called the drunken diabetes, to distinguish it from the other temporary diabetes, which occur in hysteric diseases, and from continued fear or anxiety. 2. If this idle ingurgitation of too much vinous spirit be daily practised, the urinary branch of absorbents at length gains an habit of inverting its motions, whenever the lacteals are much stimulated; and the whole or a great part of the chyle is thus daily carried to the bladder without entering the circulation, and the body becomes emaciated. This is one kind of chronic diabetes, and may be distinguished from the others by the taste and appearance of the urine; which is sweet, and the colour of whey, and may be termed the chyliferous diabetes. 3. Many children have a similar deposition of chyle in their urine, from the irritation of worms in their intestines, which stimulating the mouths of the lacteals into unnatural action, the urinary branch of the absorbents becomes inverted, and carries part of the chyle to the bladder: part of the chyle also has been carried to the iliac and lumbar glands, of which instances are recorded by Haller, t. vii. 225. and which can be explained on no other theory: but the dissections of the lymphatic system of the human body, which have yet been published, are not sufficiently extensive for our purpose; yet if we may reason from comparative anatomy, this translation of chyle to the bladder is much illustrated by the account given of this system of vessels in a turtle, by Mr. Hewson, who observed, "That the lacteals near the root of the mesentery anastomose, so as to form a net-work, from which several large branches go into some considerable lymphatics lying near the spine; and which can be traced almost to the anus, and particularly to the kidneys." Philos. Trans. v. 59. p. 199--Enquiries, p. 74. 4. At the same time that the urinary branch of absorbents, in the beginning of diabetes, is excited into inverted action, the cellular branch is excited by the sympathy above mentioned, into more energetic action; and the fat, that was before deposited, is reabsorbed and thrown into the blood vessels; where it floats, and was mistaken for chyle, till the late experiments of the ingenious Mr. Hewson demonstrated it to be fat. This appearance of what was mistaken for chyle in the blood, which was drawn from these patients, and the obstructed liver, which very frequently accompanies this disease, seems to have led Dr. Mead to suspect the diabetes was owing to a defect of sanguification; and that the schirrosity of the liver was the original cause of it: but as the schirrhus of the liver is most frequently owing to the same causes, that produce the diabetes and dropsies; namely, the great use of fermented liquors; there is no wonder they should exist together, without being the consequence of each other. 5. If the cutaneous branch of absorbents gains a habit of being excited into stronger action, and imbibes greater quantities of moisture from the atmosphere, at the same time that the urinary branch has its motions inverted, another kind of diabetes is formed, which may be termed the aqueous diabetes. In this diabetes the cutaneous absorbents frequently imbibe an amazing quantity of atmospheric moisture; insomuch that there are authentic histories, where many gallons a day, for many weeks together, above the quantity that has been drank, have been discharged by urine. Dr. Keil, in his Medicina Statica, found that he gained eighteen ounces from the moist air of one night; and Dr. Percival affirms, that one of his hands imbibed, after being well chafed, near an ounce and half of water, in a quarter of an hour. (Transact. of the College, London, vol. ii. p. 102.) Home's Medic. Facts, p. 2. sect. 3. The pale urine in hysterical women, or which is produced by fear or anxiety, is a temporary complaint of this kind; and it would in reality be the same disease, if it was confirmed by habit. 6. The purging stools, and pale urine, occasioned by exposing the naked body to cold air, or sprinkling it with cold water, originate from a similar cause; for the mouths of the cutaneous lymphatics being suddenly exposed to cold become torpid, and cease, or nearly cease, to act; whilst, by the sympathy above described, not only the lymphatics of the bladder and intestines cease also to absorb the more aqueous and saline part of the fluids secreted into them; but it is probable that these lymphatics invert their motions, and return the fluids, which were previously absorbed, into the intestines and bladder. At the very instant that the body is exposed naked to the cold air, an unusual movement is felt in the bowels; as is experienced by boys going into the cold bath: this could not occur from an obstruction of the perspirable matter, since there is not time, for that to be returned to the bowels by the course of the circulation. There is also a chronic aqueous diarrhoea, in which the atmospheric moisture, drank up by the cutaneous and pulmonary lymphatics, is poured into the intestines, by the retrograde motions of the lacteals. This disease is most similar to the aqueous diabetes, and is frequently exchanged for it: a distinct instance of this is recorded by Benningerus, Cent. v. Obs. 98. in which an aqueous diarrhoea succeeded an aqueous diabetes, and destroyed the patient. There is a curious example of this, described by Sympson (De Re Medica)--"A young man (says he) was seized with a fever, upon which a diarrhoea came on, with great stupor; and he refused to drink any thing, though he was parched up with excessive heat: the better to supply him with moisture, I directed his feet to be immersed in cold water; immediately I observed a wonderful decrease of water in the vessel, and then an impetuous stream of a fluid, scarcely coloured, was discharged by stool, like a cataract." 7. There is another kind of diarrhoea, which has been called cæliaca; in this disease the chyle, drank up by the lacteals of the small intestines, is probably poured into the large intestines, by the retrograde motions of their lacteals: as in the chyliferous diabetes, the chyle is poured into the bladder, by the retrograde motions of the urinary branch of absorbents. The chyliferous diabetes, like this chyliferous diarrhoea, produces sudden atrophy; since the nourishment, which ought to supply the hourly waste of the body, is expelled by the bladder, or rectum: whilst the aqueous diabetes, and the aqueous diarrhoea produce excessive thirst; because the moisture, which is obtained from the atmosphere, is not conveyed to the thoracic receptacle, as it ought to be, but to the bladder, or lower intestines; whence the chyle, blood, and whole system of glands, are robbed of their proportion of humidity. 8. There is a third species of diabetes, in which the urine is mucilaginous, and appears ropy in pouring it from one vessel into another; and will sometimes coagulate over the fire. This disease appears by intervals, and ceases again, and seems to be occasioned by a previous dropsy in some part of the body. When such a collection is reabsorbed, it is not always returned into the circulation; but the same irritation that stimulates one lymphatic branch to reabsorb the deposited fluid, inverts the urinary branch, and pours it into the bladder. Hence this mucilaginous diabetes is a cure, or the consequence of a cure, of a worse disease, rather than a disease itself. Dr. Cotunnius gave half an ounce of cream of tartar, every morning, to a patient, who had the anasarca; and he voided a great quantity of urine; a part of which, put over the fire, coagulated, on the evaporation of half of it, so as to look like the white of an egg. De Ischiade Nervos. This kind of diabetes frequently precedes a dropsy; and has this remarkable circumstance attending it, that it generally happens in the night; as during the recumbent state of the body, the fluid, that was accumulated in the cellular membrane, or in the lungs, is more readily absorbed, as it is less impeded by its gravity. I have seen more than one instance of this disease. Mr. D. a man in the decline of life, who had long accustomed himself to spirituous liquor, had swelled legs, and other symptoms of approaching anasarca; about once in a week, or ten days, for several months, he was seized, on going to bed, with great general uneasiness, which his attendants resembled to an hysteric fit; and which terminated in a great discharge of viscid urine; his legs became less swelled, and he continued in better health for some days afterwards. I had not the opportunity to try if this urine would coagulate over the fire, when part of it was evaporated, which I imagine would be the criterion of this kind of diabetes; as the mucilaginous fluid deposited in the cells and cysts of the body, which have no communication with the external air, seems to acquire, by stagnation, this property of coagulation by heat, which the secreted mucus of the intestines and bladder do not appear to possess; as I have found by experiment: and if any one should suppose this coagulable urine was separated from the blood by the kidneys, he may recollect, that in the most inflammatory diseases, in which the blood is most replete or most ready to part with the coagulable lymph, none of this appears in the urine. 9. Different kinds of diabetes require different methods of cure. For the first kind, or chyliferous diabetes, after clearing the stomach and intestines, by ipecacuanha and rhubarb, to evacuate any acid material, which may too powerfully stimulate the mouths of the lacteals, repeated and large doses of tincture of cantharides have been much recommended. The specific stimulus of this medicine, on the neck of the bladder, is likely to excite the numerous absorbent vessels, which are spread on that part, into stronger natural actions, and by that means prevent their retrograde ones; till, by persisting in the use of the medicine, their natural habits of motions might again be established. Another indication of cure, requires such medicines, as by lining the intestines with mucilaginous substances, or with such as consist of smooth particles, or which chemically destroy the acrimony of their contents, may prevent the too great action of the intestinal absorbents. For this purpose, I have found the earth precipitated from a solution of alum, by means of fixed alcali, given in the dose of half a dram every six hours, of great advantage, with a few grains of rhubarb, so as to produce a daily evacuation. The food should consist of materials that have the least stimulus, with calcareous water, as of Bristol and Matlock; that the mouths of the lacteals may be as little stimulated as is necessary for their proper absorption; lest with their greater exertions, should be connected by sympathy, the inverted motions of the urinary lymphatics. The same method may be employed with equal advantage in the aqueous diabetes, so great is the sympathy between the skin and the stomach. To which, however, some application to the skin might be usefully added; as rubbing the patient all over with oil, to prevent the too great action of the cutaneous absorbents. I knew an experiment of this kind made upon one patient with apparent advantage. The mucilaginous diabetes will require the same treatment, which is most efficacious in the dropsy, and will be described below. I must add, that the diet and medicines above mentioned, are strongly recommended by various authors, as by Morgan, Willis, Harris, and Etmuller; but more histories of the successful treatment of these diseases are wanting to fully ascertain the most efficacious methods of cure. In a letter from Mr. Charles Darwin, dated April 24, 1778, Edinburgh, is the subsequent passage:--"A man who had long laboured under a diabetes died yesterday in the clinical ward. He had for some time drank four, and passed twelve pounds of fluid daily; each pound of urine contained an ounce of sugar. He took, without considerable relief, gum kino, sanguis diaconis melted with alum, tincture of cantharides, isinglass, gum arabic, crabs eyes, spirit of hartshorn, and eat ten or fifteen oysters thrice a day. Dr. Home, having read my thesis, bled him, and found that neither the fresh blood nor the serum tasted sweet. His body was opened this morning--every viscus appeared in a sound and natural state, except that the left kidney had a very small pelvis, and that there was a considerable enlargement of most of the mesenteric lymphatic glands. I intend to insert this in my thesis, as it coincides with the experiment, where some asparagus was eaten at the beginning of intoxication, and its smell perceived in the urine, though not in the blood." The following case of chyliferous diabetes is extracted from some letters of Mr. Hughes, to whose unremitted care the infirmary at Stafford for many years was much indebted. Dated October 10, 1778. Richard Davis, aged 33, a whitesmith by trade, had drank hard by intervals; was much troubled with sweating of his hands, which incommoded him in his occupation, but which ceased on his frequently dipping them in lime. About seven months ago he began to make large quantities of water; his legs are oedematous, his belly tense, and he complains of a rising in his throat, like the globus hystericus: he eats twice as much as other people, drinks about fourteen pints of small beer a day, besides a pint of ale, some milk-porridge, and a bason of broth, and he makes about eighteen pints of water a day. He tried alum, dragon's blood, steel, blue vitriol, and cantharides in large quantities, and duly repeated, under the care of Dr. Underhill, but without any effect; except that on the day after he omitted the cantharides, he made but twelve pints of water, but on the next day this good effect ceased again. November 21.--He made eighteen pints of water, and he now, at Dr. Darwin's request, took a grain of opium every four hours, and five grains of aloes at night; and had a flannel shirt given him. 22.--Made sixteen pints. 23.--Thirteen pints: drinks less. 24.--Increased the opium to a grain and quarter every four hours: he made twelve pints. 25.--Increased the opium to a grain and half: he now makes ten pints; and drinks eight pints in a day. The opium was gradually increased during the next fortnight, till he took three grains every four hours, but without any further diminution of his water. During the use of the opium he sweat much in the nights, so as to have large drops stand on his face and all over him. The quantity of opium was then gradually decreased, but not totally omitted, as he continued to take about a grain morning and evening. January 17.--He makes fourteen pints of water a day. Dr. Underhill now directed him two scruples of common rosin triturated with as much sugar, every six hours; and three grains of opium every night. 19.--Makes fifteen pints of water: sweats at night. 21.--Makes seventeen pints of water; has twitchings of his limbs in a morning, and pains of his legs: he now takes a dram of rosin for a dose, and continues the opium. 23.--Water more coloured, and reduced to sixteen pints, and he thinks has a brackish taste. 26.--Water reduced to fourteen pints. 28.--Water thirteen pints: he continues the opium, and takes four scruples of the rosin for a dose. February 1.--Water twelve pints. 4.--Water eleven pints: twitchings less; takes five scruples for a dose. 8.--Water ten pints: has had many stools. 12.--Appetite less: purges very much. After this the rosin either purged him, or would not stay on his stomach; and he gradually relapsed nearly to his former condition, and in a few months sunk under the disease. October 3, Mr. Hughes evaporated two quarts of the water, and obtained from it four ounces and half of a hard and brittle saccharine mass, like treacle which had been some time boiled. Four ounces of blood, which he took from his arm with design to examine it, had the common appearances, except that the serum resembled cheese-whey; and that on the evidence of four persons, two of whom did not know what it was they tasted, _the serum had a saltish taste_. From hence it appears, that the saccharine matter, with which the urine of these patients so much abounds, does not enter the blood-vessels like the nitre and asparagus mentioned above; but that the process of digestion resembles the process of the germination of vegetables, or of making barley into malt; as the vast quantity of sugar found in the urine must be made from the food which he took (which was double that taken by others), and from the fourteen pints of small beer which he drank. And, secondly, as the serum of the blood was not sweet, the chyle appears to have been conveyed to the bladder without entering the circulation of the blood, since so large a quantity of sugar, as was found in the urine, namely, twenty ounces a day, could not have previously existed in the blood without being perceptible to the taste. November 1. Mr. Hughes dissolved two drams of nitre in a pint of a decoction of the roots of asparagus, and added to it two ounces of tincture of rhubarb: the patient took a fourth part of this mixture every five minutes, till he had taken the whole.--In about half an hour he made eighteen ounces of water, which was very manifestly tinged with the rhubarb; the smell of asparagus was doubtful. He then lost four ounces of blood, the serum of which was not so opake as that drawn before, but of a yellowish cast, as the serum of the blood usually appears. Paper, dipped three or four times in the tinged urine and dried again, did not scintillate when it was set on fire; but when the flame was blown out, the fire ran along the paper for half an inch; which, when the same paper was unimpregnated, it would not do; nor when the same paper was dipped in urine made before he took the nitre, and dried in the same manner. Paper, dipped in the serum of the blood and dried in the same manner as in the urine, did not scintillate when the flame was blown out, but burnt exactly in the same manner as the same paper dipped in the serum of blood drawn from another person. This experiment, which is copied from a letter of Mr. Hughes, as well as the former, seems to evince the existence of another passage from the intestines to the bladder, in this disease, besides that of the sanguiferous system; and coincides with the curious experiment related in section the third, except that the smell of the asparagus was not here perceived, owing perhaps to the roots having been made use of instead of the heads. The rising in the throat of this patient, and the twitchings of his limbs, seem to indicate some similarity between the diabetes and the hysteric disease, besides the great flow of pale urine, which is common to them both. Perhaps if the mesenteric glands were nicely inspected in the dissections of these patients; and if the thoracic duct, and the larger branches of the lacteals, and if the lymphatics, which arise from the bladder, were well examined by injection, or by the knife, the cause of diabetes might be more certainly understood. The opium alone, and the opium with the rosin, seem much to have served this patient, and might probably have effected a cure, if the disease had been slighter, or the medicine had been exhibited, before it had been confirmed by habit during the seven months it had continued. The increase of the quantity of water on beginning the large doses of rosin was probably owing to his omitting the morning doses of opium. V. _The Phænomena of Dropsies explained._ I. Some inebriates have their paroxysms of inebriety terminated by much pale urine, or profuse sweats, or vomiting, or stools; others have their paroxysms terminated by stupor, or sleep, without the above evacuations. The former kind of these inebriates have been observed to be more liable to diabetes and dropsy; and the latter to gout, gravel, and leprosy. Evoe! attend ye bacchanalians! start at this dark train of evils, and, amid your immodest jests, and idiot laughter, recollect, Quem Deus vult perdere, prius dementat. In those who are subject to diabetes and dropsy, the absorbent vessels are naturally more irritable than in the latter; and by being frequently disturbed or inverted by violent stimulus, and by their too great sympathy with each other, they become at length either entirely paralytic, or are only susceptible of motion from the stimulus of very acrid materials; as every part of the body, after having been used to great irritations, becomes less affected by smaller ones. Thus we cannot distinguish objects in the night, for some time after we come out of a strong light, though the iris is presently dilated; and the air of a summer evening appears cold, after we have been exposed to the heat of the day. There are no cells in the body, where dropsy may not be produced, if the lymphatics cease to absorb that mucilaginous fluid, which is perpetually deposited in them, for the purpose of lubricating their surfaces. If the lymphatic branch, which opens into the cellular membrane, either does its office imperfectly, or not at all; these cells become replete with a mucilaginous fluid, which, after it has stagnated some time in the cells, will coagulate over the fire; and is erroneously called water. Wherever the seat of this disease is, (unless in the lungs or other pendent viscera) the mucilaginous liquid above mentioned will subside to the most depending parts of the body, as the feet and legs, when those are lower than the head and trunk; for all these cells have communications with each other. When the cellular absorbents are become insensible to their usual irritations, it most frequently happens, but not always, that the cutaneous branch of absorbents, which is strictly associated with them, suffers the like inability. And then, as no water is absorbed from the atmosphere, the urine is not only less diluted at the time of its secretion, and consequently in less quantity and higher coloured: but great thirst is at the same time induced, for as no water is absorbed from the atmosphere to dilute the chyle and blood, the lacteals and other absorbent vessels, which have not lost their powers, are excited into more constant or more violent action, to supply this deficiency; whence the urine becomes still less in quantity, and of a deeper colour, and turbid like the yolk of an egg, owing to a greater absorption of its thinner parts. From this stronger action of those absorbents, which still retain their irritability, the fat is also absorbed, and the whole body becomes emaciated. This increased exertion of some branches of the lymphatics, while others are totally or partially paralytic, is resembled by what constantly occurs in the hemiplagia; when the patient has lost the use of the limbs on one side, he is incessantly moving those of the other; for the moving power, not having access to the paralytic limbs, becomes redundant in those which are not diseased. The paucity of urine and thirst cannot be explained from a greater quantity of mucilaginous fluid being deposited in the cellular membrane: for though these symptoms have continued many weeks, or even months, this collection frequently does not amount to more than very few pints. Hence also the difficulty of promoting copious sweats in anasarca is accounted for, as well as the great thirst, paucity of urine, and loss of fat; since, when the cutaneous branch of absorbents is paralytic, or nearly so, there is already too small a quantity of aqueous fluid in the blood: nor can these torpid cutaneous lymphatics be readily excited into retrograde motions. Hence likewise we understand, why in the ascites, and some other dropsies, there is often no thirst, and no paucity of urine; in these cases the cutaneous absorbents continue to do their office. Some have believed, that dropsies were occasioned by the inability of the kidneys, from having only observed the paucity of urine; and have thence laboured much to obtain diuretic medicines; but it is daily observable, that those who die of a total inability to make water, do not become dropsical in consequence of it: Fernelius mentions one, who laboured under a perfect suppression of urine during twenty days before his death, and yet had no symptoms of dropsy. Pathol. 1. vi. c. 8. From the same idea many physicians have restrained their patients from drinking, though their thirst has been very urgent; and some cases have been published, where this cruel regimen has been thought advantageous: but others of nicer observation are of opinion, that it has always aggravated the distresses of the patient; and though it has abated his swellings, yet by inducing a fever it has hastened his dissolution. See Transactions of the College, London, vol. ii. p. 235. Cases of Dropsy by Dr. G. Baker. The cure of anasarca, so far as respects the evacuation of the accumulated fluid, coincides with the idea of the retrograde action of the lymphatic system. It is well known that vomits, and other drugs, which induce sickness or nausea; at the same time that they evacuate the stomach, produce a great absorption of the lymph accumulated in the cellular membrane. In the operation of a vomit, not only the motions of the stomach and duodenum become inverted, but also those of the lymphatics and lacteals, which belong to them; whence a great quantity of chyle and lymph is perpetually poured into the stomach and intestines, during the operation, and evacuated by the mouth. Now at the same time, other branches of the lymphatic system, viz. those which open on the cellular membrane, are brought into more energetic action, by the sympathy above mentioned, and an increase of their absorption is produced. Hence repeated vomits, and cupreous salts, and small doses of squill or foxglove, are so efficacious in this disease. And as drastic purges act also by inverting the motions of the lacteals; and thence the other branches of lymphatics are induced into more powerful natural action, by sympathy, and drink up the fluids from all the cells of the body; and by their anastomoses, pour them into the lacteal branches; which, by their inverted actions, return them into the intestines; and they are thus evacuated from the body:--these purges also are used with success in discharging the accumulated fluid in anasarca. II. The following cases are related with design to ascertain the particular kinds of dropsy in which the digitalis purpurea, or common foxglove, is preferable to squill, or other evacuants, and were first published in 1780, in a pamphlet entitled Experiments on mucilaginous and purulent Matter, &c. Cadell. London. Other cases of dropsy, treated with digitalis, were afterwards published by Dr. Darwin in the Medical Transactions, vol. iii. in which there is a mistake in respect to the dose of the powder of foxglove, which should have been from five grains to one, instead of from five grains to ten. _Anasarca of the Lungs._ 1. A lady, between forty and fifty years of age, had been indisposed some time, was then seized with cough and fever, and afterwards expectorated much digested mucus. This expectoration suddenly ceased, and a considerable difficulty of breathing supervened, with a pulse very irregular both in velocity and strength; she was much distressed at first lying down, and at first rising; but after a minute or two bore either of those attitudes with ease. She had no pain or numbness in her arms; she had no hectic fever, nor any cold shiverings, and the urine was in due quantity, and of the natural colour. The difficulty of breathing was twice considerably relieved by small doses of ipecacuanha, which operated upwards and downwards, but recurred in a few days: she was then directed a decoction of foxglove, (digitalis purpurea) prepared by boiling four ounces of the fresh leaves from two pints of water to one pint; to which was added two ounces of vinous spirit: she took three large spoonfuls of this mixture every two hours, till she had taken it four times; a continued sickness supervened, with frequent vomiting, and a copious flow of urine: these evacuations continued at intervals for two or three days, and relieved the difficulty of breathing--She had some relapses afterwards, which were again relieved by the repetition of the decoction of foxglove. 2. A gentleman, about sixty years of age, who had been addicted to an immoderate use of fermented liquors, and had been very corpulent, gradually lost his strength and flesh, had great difficulty of breathing, with legs somewhat swelled, and a very irregular pulse. He was very much distressed at first lying down, and at first rising from his bed, yet in a minute or two was easy in both those attitudes. He made straw-coloured urine in due quantity, and had no pain or numbness of his arms. He took a large spoonful of the decoction of foxglove, as above, every hour, for ten or twelve successive hours, had incessant sickness for about two days, and passed a large quantity of urine; upon which his breath became quite easy, and the swelling of his legs subsided; but as his whole constitution was already sinking from the previous intemperance of his life, he did not survive more than three or four months. _Hydrops Pericardii._ 3. A gentleman of temperate life and sedulous application to business, between thirty and forty years of age, had long been subject, at intervals, to an irregular pulse: a few months ago he became weak, with difficulty of breathing, and dry cough. In this situation a physician of eminence directed him to abstain from all animal food and fermented liquor, during which regimen all his complaints increased; he now became emaciated, and totally lost his appetite; his pulse very irregular both in velocity and strength; with great difficulty of breathing, and some swelling of his legs; yet he could lie down horizontally in his bed, though he got little sleep, and passed a due quantity of urine, and of the natural colour: no fullness or hardness could be perceived about the region of the liver; and he had no pain or numbness in his arms. One night he had a most profuse sweat all over his body and limbs, which quite deluged his bed, and for a day or two somewhat relieved his difficulty of breathing, and his pulse became less irregular: this copious sweat recurred three or four times at the intervals of five or six days, and repeatedly alleviated his symptoms. He was directed one large spoonful of the above decoction of foxglove every hour, till it procured some considerable evacuation: after he had taken it eleven successive hours he had a few liquid stools, attended with a great flow of urine, which last had a dark tinge, as if mixed with a few drops of blood: he continued sick at intervals for two days, but his breath became quite easy, and his pulse quite regular, the swelling of his legs disappeared, and his appetite and sleep returned. He then took three grains of white vitriol twice a day, with some bitter medicines, and a grain of opium with five grains of rhubarb every night; was advised to eat flesh meat, and spice, as his stomach would bear it, with small beer, and a few glasses of wine; and had issues made in his thighs; and has suffered no relapse. 4. A lady, about fifty years of age, had for some weeks great difficulty of breathing, with very irregular pulse, and considerable general debility: she could lie down in bed, and the urine was in due quantity and of the natural colour, and she had no pain or numbness of her arms. She took one large spoonful of the above decoction of foxglove every hour, for ten or twelve successive hours; was sick, and made a quantity of pale urine for about two days, and was quite relieved both of the difficulty of breathing, and the irregularity of her pulse. She then took a grain of opium, and five grains of rhubarb, every night, night, for many weeks; with some slight chalybeate and bitter medicines, and has suffered no relapse. _Hydrops Thoracis._ 5. A tradesman, about fifty years of age, became weak and short of breath, especially on increase of motion, with pain in one arm, about the insertion of the biceps muscle. He observed he sometimes in the night made an unusual quantity of pale water. He took calomel, alum, and peruvian bark, and all his symptoms increased: his legs began to swell considerably; his breath became more difficult, and he could not lie down in bed; but all this time he made a due quantity of straw-coloured water. The decoction of foxglove was given as in the preceding cases, which operated chiefly by purging, and seemed to relieve his breath for a day or two; but also seemed to contribute to weaken him.--He became after some weeks universally dropsical, and died comatous. 6. A young lady of delicate constitution, with light eyes and hair, and who had perhaps lived too abstemiously both in respect to the quantity and quality of what she eat and drank, was seized with great difficulty of breathing, so as to threaten immediate death. Her extremities were quite cold, and her breath felt cold to the back of one's hand. She had no sweat, nor could be down for a single moment; and had previously, and at present, complained of great weakness and pain and numbness of both her arms; had no swelling of her legs, no thirst, water in due quantity and colour. Her sister, about a year before, was afflicted with similar symptoms, was repeatedly blooded, and died universally dropsical. A grain of opium was given immediately, and repeated every six hours with evident and amazing advantage; afterwards a blister, with chalybeates, bitters, and essential oils, were exhibited, but nothing had such eminent effect in relieving the difficulty of breathing and coldness of her extremities as opium, by the use of which in a few weeks she perfectly regained her health, and has suffered no relapse. _Ascites._ 7. A young lady of delicate constitution having been exposed to great fear, cold, and fatigue, by the overturn of a chaise in the night, began with pain and tumour in the right hypochondrium: in a few months a fluctuation was felt throughout the whole abdomen, more distinctly perceptible indeed about the region of the stomach; since the integuments of the lower part of the abdomen generally become thickened in this disease by a degree of anasarca. Her legs were not swelled, no thirst, water in due quantity and colour.--She took the foxglove so as to induce sickness and stools, but without abating the swelling, and was obliged at length to submit to the operation of tapping. 8. A man about sixty-seven, who had long been accustomed to spirituous potation, had some time laboured under ascites; his legs somewhat swelled; his breath easy in all attitudes; no appetite; great thirst; urine in exceedingly small quantity, very deep coloured, and turbid; pulse equal. He took the foxglove in such quantity as vomited him, and induced sickness for two days; but procured no flow of urine, or diminution of his swelling; but was thought to leave him considerably weaker. 9. A corpulent man, accustomed to large potation of fermented liquors, had vehement cough, difficult breathing, anasarca of his legs, thighs, and hands, and considerable tumour, with evident fluctuation of his abdomen; his pulse was equal; his urine in small quantity, of deep colour, and turbid. These swellings had been twice considerably abated by drastic cathartics. He took three ounces of a decoction of foxglove (made by boiling one ounce of the fresh leaves in a pint of water) every three hours, for two whole days; it then began to vomit and purge him violently, and promoted a great flow of urine; he was by these evacuations completely emptied in twelve hours. After two or three months all these symptoms returned, and were again relieved by the use of the foxglove; and thus in the space of about three years he was about ten times evacuated, and continued all that time his usual potations: excepting at first, the medicine operated only by urine, and did not appear considerably to weaken him--The last time he took it, it had no effect; and a few weeks afterwards he vomited a great quantity of blood, and expired. QUERIES. 1. As the first six of these patients had a due discharge of urine, and of the natural colour, was not the feat of the disease confined to some part of the thorax, and the swelling of the legs rather a symptom of the obstructed circulation of the blood, than of a paralysis of the cellular lymphatics of those parts? 2. When the original disease is a general anasarca, do not the cutaneous lymphatics always become paralytic at the same time with the cellular ones, by their greater sympathy with each other? and hence the paucity of urine, and the great thirst, distinguish this kind of dropsy? 3. In the anasarca of the lungs, when the disease is not very great, though the patients have considerable difficulty of breathing at their first lying down, yet after a minute or two their breath becomes easy again; and the same occurs at their first rising. Is not this owing to the time necessary for the fluid in the cells of the lungs to change its place, so as the least to incommode respiration in the new attitude? 4. In the dropsy of the pericardium does not the patient bear the horizontal or perpendicular attitude with equal ease? Does this circumstance distinguish the dropsy of the pericardium from that of the lungs and of the thorax? 5. Do the universal sweats distinguish the dropsy of the pericardium, or of the thorax? and those, which cover the upper parts of the body only, the anasarca of the lungs? 6. When in the dropsy of the thorax, the patient endeavours to lie down, does not the extravasated fluid compress the upper parts of the bronchia, and totally preclude the access of air to every part of the lungs; whilst in the perpendicular attitude the inferior parts of the lungs only are compressed? Does not something similar to this occur in the anasarca of the lungs, when the disease is very great, and thus prevent those patients also from lying down? 7. As a principal branch of the fourth cervical nerve of the left side, after having joined a branch of the third and of the second cervical nerves, descending between the subclavian vein and artery, is received in a groove formed for it in the pericardium, and is obliged to make a considerable turn outwards to go over the prominent part of it, where the point of the heart is lodged, in its course to the diaphragm; and as the other phrenic nerve of the right side has a straight course to the diaphragm; and as many other considerable branches of this fourth pair of cervical nerves are spread on the arms; does not a pain in the left arm distinguish a disease of the pericardium, as in the angina pectoris, or in the dropsy of the pericardium? and does not a pain or weakness in both arms distinguish the dropsy of the thorax? 8. Do not the dropsies of the thorax and pericardium frequently exist together, and thus add to the uncertainty and fatality of the disease? 9. Might not the foxglove be serviceable in hydrocephalus internus, in hydrocele, and in white swellings of the joints? VI. _Of cold Sweats._ There have been histories given of chronical immoderate sweatings, which bear some analogy to the diabetes. Dr. Willis mentions a lady then living, whose sweats where for many years so profuse, that all her bed-clothes were not only moistened, but deluged with them every night; and that many ounces, and sometimes pints, of this sweat, were received in vessels properly placed, as it trickled down her body. He adds, that she had great thirst, had taken many medicines, and submitted to various rules of life, and changes of climate, but still continued to have these immoderate sweats. Pharmac. ration. de sudore anglico. Dr. Willis has also observed, that the sudor anglicanus which appeared in England, in 1483, and continued till 1551, was in some respects similar to the diabetes; and as Dr. Caius, who saw this disease, mentions the viscidity, as well as the quantity of these sweats, and adds, that the extremities were often cold, when the internal parts were burnt up with heat and thirst, with great and speedy emaciation and debility: there is great reason to believe, that the fluids were absorbed from the cells of the body by the cellular and cystic branches of the lymphatics, and poured on the skin by the retrograde motions of the cutaneous ones. Sydenham has recorded, in the stationary fever of the year 1685, the viscid sweats flowing from the head, which were probably from the same source as those in the sweating plague above mentioned. It is very common in dropsies of the chest or lungs to have the difficulty of breathing relieved by copious sweats, flowing from the head and neck. Mr. P. about 50 years of age, had for many weeks been afflicted with anasarca of his legs and thighs, attended with difficulty of breathing; and had repeatedly been relieved by squill, other bitters, and chalybeates.--One night the difficulty of breathing became so great, that it was thought he must have expired; but so copious a sweat came out of his head and neck, that in a few hours some pints, by estimation, were wiped off from those parts, and his breath was for a time relieved. This dyspnoea and these sweats recurred at intervals, and after some weeks he ceased to exist. The skin of his head and neck felt cold to the hand, and appeared pale at the time these sweats flowed so abundantly; which is a proof, that they were produced by an inverted motion of the absorbents of those parts: for sweats, which are the consequence of an increased action of the sanguiferous system, are always attended with a warmth of the skin, greater than is natural, and a more florid colour; as the sweats from exercise, or those that succeed the cold fits of agues. Can any one explain how these partial sweats should relieve the difficulty of breathing in anasarca, but by supposing that the pulmonary branch of absorbents drank up the fluid in the cavity of the thorax, or in the cells of the lungs, and threw it on the skin, by the retrograde motions of the cutaneous branch? for, if we could suppose, that the increased action of the cutaneous glands or capillaries poured upon the skin this fluid, previously absorbed from the lungs; why is not the whole surface of the body covered with sweat? why is not the skin warm? Add to this, that the sweats above mentioned were clammy or glutinous, which the condensed perspirable matter is not; whence it would seem to have been a different fluid from that of common perspiration. Dr. Dobson, of Liverpool, has given a very ingenious explanation of the acid sweats, which he observed in a diabetic patient--he thinks part of the chyle is secreted by the skin, and afterwards undergoes an acetous fermentation.--Can the chyle get thither, but by an inverted motion of the cutaneous lymphatics? in the same manner as it is carried to the bladder, by the inverted motions of the urinary lymphatics. Medic. Observat. and Enq. London, vol. v. Are not the cold sweats in some fainting fits, and in dying people, owing to an inverted motion of the cutaneous lymphatics? for in these there can be no increased arterial or glandular action. Is the difficulty of breathing, arising from anasarca of the lungs, relieved by sweats from the head and neck; whilst that difficulty of breathing, which arises from a dropsy of the thorax, or pericardium, is never attended with these sweats of the head? and thence can these diseases be distinguished from each other? Do the periodic returns of nocturnal asthma rise from a temporary dropsy of the lungs, collected during their more torpid state in sound deep, and then re-absorbed by the vehement efforts of the disordered organs of respiration, and carried off by the copious sweats about the head and neck? More extensive and accurate dissections of the lymphatic system are wanting to enable us to unravel these knots of science. VII. _Translations of Matter, of Chyle, of Milk, of Urine. Operation of purging Drugs applied externally._ 1. The translations of matter from one part of the body to another, can only receive an explanation from the doctrine of the occasional retrograde motions of some branches of the lymphatic system: for how can matter, absorbed and mixed with the whole mass of blood, be so hastily collected again in any one part? and is it not an immutable law, in animal bodies, that each gland can secrete no other, but its own proper fluid? which is, in part, fabricated in the very gland by an animal process, which it there undergoes: of these purulent translations innumerable and very remarkable instances are recorded. 2. The chyle, which is seen among the materials thrown up by violent vomiting, or in purging stools, can only come thither by its having been poured into the bowels by the inverted motions of the lacteals: for our aliment is not converted into chyle in the stomach or intestines by a chemical process, but is made in the very mouths of the lacteals; or in the mesenteric glands; in the same manner as other secreted fluids are made by an animal process in their adapted glands. Here a curious phænomenon in the exhibition of mercury is worth explaining:--If a moderate dose of calomel, as six or ten grains, be swallowed, and within one or two days a cathartic is given, a salivation is prevented: but after three or four days, a salivation having come on, repeated purges every day, for a week or two, are required to eliminate the mercury from the constitution. For this acrid metallic preparation, being absorbed by the mouth of the lacteals, continues, for a time arrested by the mesenteric glands, (as the variolous or venereal poisons swell the subaxillar or inguinal glands): which, during the operation of a cathartic, is returned into the intestines by the inverted action of the lacteals, and thus carried out of the system. Hence we understand the use of vomits or purges, to those who have swallowed either contagious or poisonous materials, even though exhibited a day or even two days after such accidents; namely, that by the retrograde motions of the lacteals and lymphatics, the material still arrested in the mesenteric, or other glands, may be eliminated from the body. 3. Many instances of milk and chyle found in ulcers are given by Haller, El. Physiol. t. vii. p. 12, 23, which admit of no other explanation than by supposing, that the chyle, imbibed by one branch of the absorbent system, was carried to the ulcer, by the inverted motions of another branch of the same system. 4. Mrs. P. on the second day after delivery, was seized with a violent purging, in which, though opiates, mucilages, the bark, and testacea were profusely used, continued many days, till at length she recovered. During the time of this purging, no milk could be drawn from her breasts; but the stools appeared like the curd of milk broken into small pieces. In this case, was not the milk taken up from the follicles of the pectoral glands, and thrown on the intestines, by a retrogression of the intestinal absorbents? for how can we for a moment suspect that the mucous glands of the intestines could separate pure milk from the blood? Doctor Smelly has observed, that loose stools, mixed with milk, which is curdled in the intestines, frequently relieves the turgescency of the breasts of those who studiously repel their milk. Cases in Midwifery, 43, No. 2. 1. 5. J.F. Meckel observed in a patient, whose urine was in small quantity and high coloured, that a copious sweat under the arm-pits, of a perfectly urinous smell, stained the linen; which ceased again when the usual quantity of urine was discharged by the urethra. Here we must believe from analogy, that the urine was first secreted in the kidneys, then re-absorbed by the increased action of the urinary lymphatics, and lastly carried to the axillae by the retrograde motions of the lymphatic branches of those parts. As in the jaundice it is necessary, that the bile should first be secreted by the liver, and re-absorbed into the circulation, to produce the yellowness of the skin; as was formerly demonstrated by the late Dr. Munro, (Edin. Medical Essays) and if in this patient the urine had been re-absorbed into the mass of blood, as the bile in the jaundice, why was it not detected in other parts of the body, as well as in the arm-pits? 6. Cathartic and vermifuge medicines applied externally to the abdomen, seem to be taken up by the cutaneous branch of lymphatics, and poured on the intestines by the retrograde motions of the lacteals, without having passed the circulation. For when the drastic purges are taken by the mouth, they excite the lacteals of the intestines into retrograde motions, as appears from the chyle, which is found coagulated among the fæces, as was shewn above, (sect. 2 and 4.) And as the cutaneous lymphatics are joined with the lacteals of the intestines, by frequent anastomoses; it would be more extraordinary, when a strong purging drug, absorbed by the skin, is carried to the anastomosing branches of the lacteals unchanged, if it should not excite them into retrograde action as efficaciously, as if it was taken by the mouth, and mixed with the food of the stomach. VIII. _Circumstances by which the Fluids, that are effused by the retrograde Motions of the absorbent Vessels, are distinguished._ 1. We frequently observe an unusual quantity of mucus or other fluids in some diseases, although the action of the glands, by which those fluids are separated from the blood, is not unusually increased; but when the power of absorption alone is diminished. Thus the catarrhal humour from the nostrils of some, who ride in frosty weather; and the tears, which run down the cheeks of those, who have an obstruction of the puncta lacrymalia; and the ichor of those phagedenic ulcers, which are not attended with inflammation, are all instances of this circumstance. These fluids however are easily distinguished from others by their abounding in ammoniacal or muriatic salts; whence they inflame the circumjacent skin: thus in the catarrh the upper lip becomes red and swelled from the acrimony of the mucus, and patients complain of the saltness of its taste. The eyes and cheeks are red with the corrosive tears, and the ichor of some herpetic eruptions erodes far and wide the contiguous parts, and is pungently salt to the taste, as some patients have informed me. Whilst, on the contrary, those fluids, which are effused by the retrograde action of the lymphatics, are for the most part mild and innocent; as water, chyle, and the natural mucus: or they take their properties from the materials previously absorbed, as in the coloured or vinous urine, or that scented with asparagus, described before. 2. Whenever the secretion of any fluid is increased, there is at the same time an increased heat in the part; for the secreted fluid, as the bile, did not previously exist in the mass of blood, but a new combination is produced in the gland. Now as solutions are attended with cold, so combinations are attended with heat; and it is probable the sum of the heat given out by all the secreted fluids of animal bodies may be the cause of their general heat above that of the atmosphere. Hence the fluids derived from increased secretions are readily distinguished from those originating from the retrograde motions of the lymphatics: thus an increase of heat either in the diseased parts, or diffused over the whole body, is perceptible, when copious bilious stools are consequent to an inflamed liver; or a copious mucous salivation from the inflammatory angina. 3. When any secreted fluid is produced in an unusual quantity, and at the same time the power of absorption is increased in equal proportion, not only the heat of the gland becomes more intense, but the secreted fluid becomes thicker and milder, its thinner and saline parts being re-absorbed: and these are distinguishable both by their greater consistence, and by their heat, from the fluids, which are effused by the retrograde motions of the lymphatics; as is observable towards the termination of gonorrhoea, catarrh, chincough, and in those ulcers, which are said to abound with laudable pus. 4. When chyle is observed in stools, or among the materials ejected by vomit, we may be confident it must have been brought thither by the retrograde motions of the lacteals; for chyle does not previously exist amid the contents of the intestines, but is made in the very mouths of the lacteals, as was before explained. 5. When chyle, milk, or other extraneous fluids are found in the urinary bladder, or in any other excretory receptacle of a gland; no one can for a moment believe, that these have been collected from the mass of blood by a morbid secretion, as it contradicts all analogy. ---- Aurea duræ Mala ferant quercus? Narcisco floreat alnus? Pinguia corticibus sudent electra myricæ?--VIRGIL. IX. _Retrograde Motions of Vegetable juices._ There are besides some motions of the sap in vegetables, which bear analogy to our present subject; and as the vegetable tribes are by many philosophers held to be inferior animals, it may be a matter of curiosity at least to observe, that their absorbent vessels seem evidently, at times, to be capable of a retrograde motion. Mr. Perault cut off a forked branch of a tree, with the leaves on; and inverting one of the forks into a vessel of water, observed, that the leaves on the other branch continued green much longer than those of a similar branch, cut off from the same tree; which shews, that the water from the vessel was carried up one part of the forked branch, by the retrograde motion of its vessels, and supplied nutriment some time to the other part of the branch, which was out of the water. And the celebrated Dr. Hales found, by numerous very accurate experiments, that the sap of trees rose upwards during the warmer hours of the day, and in part descended again during the cooler ones. Vegetable Statics. It is well known that the branches of willows, and of many other trees, will either take root in the earth or engraft on other trees, so as to have their natural direction inverted, and yet flourish with vigour. Dr. Hope has also made this pleasing experiment, after the manner of Hales--he has placed a forked branch, cut from one tree, erect between two others; then cutting off a part of the bark from one fork applied it to a similar branch of one of the trees in its vicinity; and the same of the other fork; so that a tree is seen to grow suspended in the air, between two other trees; which supply their softer friend with due nourishment. Miranturque novas frondes, et non sua poma. All these experiments clearly evince, that the juices of vegetables can occasionally pass either upwards or downwards in their absorbent system of vessels. X. _Objections answered._ The following experiment, at first view, would seem to invalidate this opinion of the retrograde motions of the lymphatic vessels, in some diseases. About a gallon of milk having been giving to an hungry swine, he was suffered to live about an hour, and was then killed by a stroke or two on his head with an axe.--On opening his belly the lacteals were well seen filled with chyle; on irritating many of the branches of them with a knife, they did not appear to empty themselves hastily; but they did however carry forwards their contents in a little time. I then passed a ligature round several branches of lacteals, and irritated them much with a knife beneath the ligature, but could not make them regurgitate their contained fluid into the bowels. I am not indeed certain, that the nerve was not at the same time included in the ligature, and thus the lymphatic rendered unirritable or lifeless; but this however is certain, that it is not any quantity of any stimulus, which induces the vessels of animal bodies to revert their motions; but a certain quantity of a certain stimulus, as appears from wounds in the stomach, which do not produce vomiting; and wounds of the intestines, which do not produce the cholera morbus. At Nottingham, a few years ago, two shoemakers quarrelled, and one of them with a knife, which they use in their occupation, stabbed his companion about the region of the stomach. On opening the abdomen of the wounded man after his death the food and medicines he had taken were in part found in the cavity of the belly, on the outside of the bowels; and there was a wound about half an inch long at the bottom of the stomach; which I suppose was distended with liquor and food at the time of the accident; and thence was more liable to be injured at its bottom: but during the whole time he lived, which was about ten days, he had no efforts to vomit, nor ever even complained of being sick at the stomach! Other cases similar to this are mentioned in the philosophical transactions. Thus, if you vellicate the throat with a feather, nausea is produced; if you wound it with a penknife, pain is induced, but not sickness. So if the soles of the feet of children or their armpits are tickled, convulsive laughter is excited, which ceases the moment the hand is applied, so as to rub them more forcibly. The experiment therefore above related upon the lacteals of a dead pig, which were included in a strict ligature, proves nothing; as it is not the quantity, but the kind of stimulus, which excites the lymphatic vessels into retrograde motion. XI. _The Causes which induce the retrograde Motions of animal Vessels; and the Medicines by which the natural Motions are restored._ 1. Such is the construction of animal bodies, that all their parts, which are subjected to less stimuli than nature designed, perform their functions with less accuracy: thus, when too watery or too acescent food is taken into the stomach, indigestion, and flatulency, and heartburn succeed. 2. Another law of irritation, connate with our existence, is, that all those parts of the body, which have previously been exposed to too great a quantity of such stimuli, as strongly affect them, become for some time afterwards disobedient to the natural quantity of their adapted stimuli.--Thus the eye is incapable of seeing objects in an obscure room, though the iris is quite dilated, after having been exposed to the meridian sun. 3. There is a third law of irritation, that all the parts of our bodies, which have been lately subjected to less stimulus, than they have been accustomed to, when they are exposed to their usual quantity of stimulus, are excited into more energetic motions: thus when we come from a dusky cavern into the glare of daylight, our eyes are dazzled; and after emerging from the cold bath, the skin becomes warm and red. 4. There is a fourth law of irritation, that all the parts of our bodies, which are subjected to still stronger stimuli for a length of time, become torpid, and refuse to obey even these stronger stimuli; and thence do their offices very imperfectly.--Thus, if any one looks earnestly for some minutes on an area, an inch diameter, of red silk, placed on a sheet of white paper, the image of the silk will gradually become pale, and at length totally vanish. 5. Nor is it the nerves of sense alone, as the optic and auditory nerves, that thus become torpid, when the stimulus is withdrawn or their irritability decreased; but the motive muscles, when they are deprived of their natural stimuli, or of their irritability, become torpid and paralytic; as is seen in the tremulous hand of the drunkard in a morning; and in the awkward step of age. The hollow muscles also, of which the various vessels of the body are constructed, when they are deprived of their natural stimuli, or of their due degree of irritability, not only become tremulous, as the arterial pulsations of dying people; but also frequently invert their motions, as in vomiting, in hysteric suffocations, and diabetes above described. I must beg your patient attention, for a few moments whilst I endeavour to explain, how the retrograde actions of our hollow muscles are the consequence of their debility; as the tremulous actions of the solid muscles are the consequence of their debility. When, through fatigue, a muscle can act no longer; the antagonist muscles, either by their inanimate elasticity, or by their animal action, draw the limb into a contrary direction: in the solid muscles, as those of locomotion, their actions are associated in tribes, which have been accustomed to synchronous action only; hence when they are fatigued, only a single contrary effort takes place; which is either tremulous, when the fatigued muscles are again immediately brought into action; or it is a pandiculation, or stretching, where they are not immediately again brought into action. Now the motions of the hollow muscles, as they in general propel a fluid along their cavities, are associated in trains, which have been accustomed to successive actions: hence when one ring of such a muscle is fatigued from its too great debility, and is brought into retrograde action, the next ring from its association falls successively into retrograde action; and so on throughout the whole canal. See Sect. XXV. 6. 6. But as the retrograde motions of the stomach, oesophagus, and fauces in vomiting are, as it were, apparent to the eye; we shall consider this operation more minutely, that the similar operations in the more recondite parts of our system may be easier understood. From certain nauseous ideas of the mind, from an ungrateful taste in the mouth, or from foetid smells, vomiting is sometimes instantly excited; or even from a stroke on the head, or from the vibratory motions of a ship; all which originate from association, or sympathy. See Sect. XX. on Vertigo. But when the stomach is subjected to a less stimulus than is natural, according to the first law of irritation mentioned above, its motions become disturbed, as in hunger; first pain is produced, then sickness, and at length vain efforts to vomit, as many authors inform us. But when a great quantity of wine, or of opium, is swallowed, the retrograde motions of the stomach do not occur till after several minutes, or even hours; for when the power of so strong a stimulus ceases, according to the second law of irritation, mentioned above, the peristaltic motions become tremulous, and at length retrograde; as is well known to the drunkard, who on the next morning has sickness and vomitings. When a still greater quantity of wine, or of opium, or when nauseous vegetables, or strong bitters, or metallic salts, are taken into the stomach, they quickly induce vomiting; though all these in less doses excite the stomach into more energetic action, and strengthen the digestion; as the flowers of chamomile, and the vitriol of zinc: for, according to the fourth law of irritation, the stomach will not long be obedient to a stimulus so much greater than is natural; but its action becomes first tremulous and then retrograde. 7. When the motions of any vessels become retrograde, less heat of the body is produced; for in paroxysms of vomiting, of hysteric affections, of diabetes, of asthma, the extremities of the body are cold: hence we may conclude, that these symptoms arise from the debility of the parts in action; for an increase of muscular action is always attended with increase of heat. 8. But as animal debility is owing to defect of stimulus, or to defect of irritability, as shewn above, the method of cure is easily deduced: when the vascular muscles are not excited into their due action by the natural stimuli, we should exhibit those medicines, which possess a still greater degree of stimulus; amongst these are the foetids, the volatiles, aromatics, bitters, metallic salts, opiates, wine, which indeed should be given in small doses, and frequently repeated. To these should be added constant, but moderate exercise, cheerfulness of mind, and change of country to a warmer climate; and perhaps occasionally the external stimulus of blisters. It is also frequently useful to diminish the quantity of natural stimulus for a short time, by which afterwards the irritability of the system becomes increased; according to the third law of irritation above-mentioned, hence the use of baths somewhat colder than animal heat, and of equitation in the open air. _The catalogue of diseases owing to the retrograde motions of lymphatics is here omitted, as it will appear in the second volume of this work. The following is the conclusion to this thesis of_ Mr. CHARLES DARWIN. Thus have I endeavoured in a concise manner to explain the numerous diseases, which deduce their origin from the inverted motions of the hollow muscles of our bodies: and it is probable, that Saint Vitus's dance, and the stammering of speech, originate from a similar, inverted order of the associated motions of some of the solid muscles; which, as it is foreign to my present purpose, I shall not here discuss. I beg, illustrious professors, and ingenious fellow-students, that you will recollect how difficult a talk I have attempted, to evince the retrograde motions of the lymphatic vessels, when the vessels themselves for so many ages escaped the eyes and glasses of philosophers: and if you are not yet convinced of the truth of this theory, hold, I entreat you, your minds in suspense, till ANATOMY draws her sword with happier omens, cuts asunder the knots, which entangle PHYSIOLOGY; and, like an augur inspecting the immolated victim, announces to mankind the wisdom of HEAVEN. * * * * * SECT. XXX. PARALYSIS OF THE LIVER AND KIDNEYS. I. 1._Bile-ducts less irritable after having been stimulated much._ 2. _Jaundice from paralysis of the bile-ducts cured by electric shocks._ 3. _From bile-stones. Experiments on bile-stones. Oil vomit._ 4. _Palsy of the liver, two cases._ 5. _Schirrosity of the liver._ 6. _Large livers of geese._ II. _Paralysis of the kidneys._ III. _Story of Prometheus._ I. 1. From the ingurgitation of spirituous liquors into the stomach and duodenum, the termination of the common bile-duct in that bowel becomes stimulated into unnatural action, and a greater quantity of bile is produced from all the secretory vessels of the liver, by the association of their motions with those of their excretory ducts; as has been explained in Section XXIV. and XXV. but as all parts of the body, that have been affected with stronger stimuli for any length of time, become less susceptible of motion, from their natural weaker stimuli, it follows, that the motions of the secretory vessels, and in consequence the secretion of bile, is less than is natural during the intervals of sobriety. 2. If this ingurgitation of spirituous liquors has been daily continued in considerable quantity, and is then suddenly intermitted, a languor or paralysis of the common bile-duct is induced; the bile is prevented from being poured into the intestines; and as the bilious absorbents are stimulated into stronger action by its accumulation, and by the acrimony or viscidity, which it acquires by delay, it is absorbed, and carried to the receptacle of the chyle; or otherwise the secretory vessels of the liver, by the above-mentioned stimulus, invert their motions, and regurgitate their contents into the blood, as sometimes happens to the tears in the lachrymal sack, see Sect. XXIV. 2. 7. and one kind of jaundice is brought on. There is reason to believe, that the bile is most frequently returned into the circulation by the inverted motions of these hepatic glands, for the bile does not seem liable to be absorbed by the lymphatics, for it soaks through the gall-ducts, and is frequently found in the cellular membrane. This kind of jaundice is not generally attended with pain, neither at the extremity of the bile-duct, where it enters the duodenum, nor on the region of the gall-bladder. Mr. S. a gentleman between 40 and 50 years of age, had had the jaundice about six weeks, without pain, sickness, or fever; and had taken emetics, cathartics, mercurials, bitters, chalybeates, essential oil, and ether, without apparent advantage. On a supposition that the obstruction of the bile might be owing to the paralysis, or torpid action of the common bile-duct, and the stimulants taken into the stomach seeming to have no effect, I directed half a score smart electric shocks from a coated bottle, which held about a quart, to be passed through the liver, and along the course of the common gall-duct, as near as could be guessed, and on that very day the stools became yellow; he continued the electric shocks a few days more, and his skin gradually became clear. 3. The bilious vomiting and purging, that affects some people by intervals of a few weeks, is a less degree of this disease; the bile-duct is less irritable than natural, and hence the bile becomes accumulated in the gall-bladder, and hepatic ducts, till by its quantity, acrimony or viscidity, a greater degree of irritation is produced, and it is suddenly evacuated, or lastly from the absorption of the more liquid parts of the bile, the remainder becomes inspissated, and chrystallizes into masses too large to pass, and forms another kind of jaundice, where the bile-duct is not quite paralytic, or has regained its irritability. This disease is attended with much pain, which at first is felt at the pit of the stomach, exactly in the centre of the body, where the bile-duct enters the duodenum; afterwards, when the size of the bile-stones increase, it is also felt on the right side, where the gall-bladder is situated. The former pain at the pit of the stomach recurs by intervals, as the bile-stone is pushed against the neck of the duct; like the paroxysms of the stone in the urinary bladder, the other is a more dull and constant pain. Where these bile-stones are too large to pass, and the bile-ducts possess their sensibility, this becomes a very painful and hopeless disease. I made the following experiments with a view to their chemical solution. Some fragments of the same bile-stone were put into the weak spirit of marine salt, which is sold in the shops, and into solution of mild alcali; and into a solution of caustic alcali; and into oil of turpentine; without their being dissolved. All these mixtures were after some time put into a heat of boiling water, and then the oil of turpentine dissolved its fragments of bile-stone, but no alteration was produced upon those in the other liquids except some change of their colour. Some fragments of the same bile-stone were put into vitriolic æther, and were quickly dissolved without additional heat. Might not æther mixed with yolk of egg or with honey be given advantageously in bilious concretions? I have in two instances seen from 30 to 50 bile-stones come away by stool, about the size of large peas, after having given six grains of calomel in the evening, and four ounces of oil of almonds or olives on the succeeding morning. I have also given half a pint of good olive or almond oil as an emetic during the painful fit, and repeated it in half an hour, if the first did not operate, with frequent good effect. 4. Another disease of the liver, which I have several times observed, consists in the inability or paralysis of the secretory vessels. This disease has generally the same cause as the preceding one, the too frequent potation of spirituous liquors, or the too sudden omission of them, after the habit is confined; and is greater or less in proportion, as the whole or a part of the liver is affected, and as the inability or paralysis is more or less complete. This palsy of the liver is known from these symptoms, the patients have generally passed the meridian of life, have drank fermented liquors daily, but perhaps not been opprobrious drunkards; they lose their appetite, then their flesh and strength diminish in consequence, there appears no bile in their stools, nor in their urine, nor is any hardness or swelling perceptible on the region of the liver. But what is peculiar to this disease, and distinguishes it from all others at the first glance of the eye, is the bombycinous colour of the skin, which, like that of full-grown silkworms, has a degree of transparency with a yellow tint not greater than is natural to the serum of the blood. Mr. C. and Mr. B. both very strong men, between 50 and 60 years of age, who had drank ale at their meals instead of small beer, but were not reputed hard-drinkers, suddenly became weak, lost their appetite, flesh, and strength, with all the symptoms above enumerated, and died in about two months from the beginning of their malady. Mr. C. became anasarcous a few days before his death, and Mr. B. had frequent and great hæmorrhages from an issue, and some parts of his mouth, a few days before his death. In both these cases calomel, bitters and chalybeates were repeatedly used without effect. One of the patients described above, Mr. C, was by trade a plumber; both of them could digest no food, and died apparently for want of blood. Might not the transfusion of blood be used in these cases with advantage? 5. When the paralysis of the hepatic glands is less complete, or less universal, a schirrosity of some part of the liver is induced; for the secretory vessels retaining some of their living power take up a fluid from the circulation, without being sufficiently irritable to carry it forwards to their excretory ducts; hence the body, or receptacle of each gland, becomes inflated, and this distension increases, till by its very great stimulus inflammation is produced, or till those parts of the viscus become totally paralytic. This disease is distinguishable from the foregoing by the palpable hardness or largeness of the liver; and as the hepatic glands are not totally paralytic, or the whole liver not affected, some bile continues to be made. The inflammations of this viscus, consequent to the schirrosity of it, belong to the diseases of the sensitive motions, and will be treated of hereafter. 6. The ancients are said to have possessed an art of increasing the livers of geese to a size greater than the remainder of the goose. Martial. l. 13. epig. 58.--This is said to have been done by fat and figs. Horace, l. 2. sat. 8.--Juvenal sets these large livers before an epicure as a great rarity. Sat. 5. l. 114; and Persius, sat. 6. l. 71. Pliny says these large goose-livers were soaked in mulled milk, that is, I suppose, milk mixed with honey and wine; and adds, "that it is uncertain whether Scipio Metellus, of consular dignity, or M. Sestius, a Roman knight, was the great discoverer of this excellent dish." A modern traveller, I believe Mr. Brydone, asserts that the art of enlarging the livers of geese still exists in Sicily; and it is to be lamented that he did not import it into his native country, as some method of affecting the human liver might perhaps have been collected from it; besides the honour he might have acquired in improving our giblet pies. Our wiser caupones, I am told, know how to fatten their fowls, as well as their geese, for the London markets, by mixing gin instead of figs and fat with their food; by which they are said to become sleepy, and to fatten apace, and probably acquire enlarged livers; as the swine are asserted to do, which are fed on the sediments of barrels in the distilleries; and which so frequently obtains in those, who ingurgitate much ale, or wine, or drams. II. The irritative diseases of the kidneys, pancreas, spleen, and other glands, are analogous to those of the liver above described, differing only in the consequences attending their inability to action. For instance, when the secretory vessels of the kidneys become disobedient to the stimulus of the passing current of blood, no urine is separated or produced by them; their excretory mouths become filled with concreted mucus, or calculus matter, and in eight or ten days stupor and death supervenes in consequence of the retention of the feculent part of the blood. This disease in a slighter degree, or when only a part of the kidney is affected, is succeeded by partial inflammation of the kidney in consequence of previous torpor. In that case greater actions of the secretory vessels occur, and the nucleus of gravel is formed by the inflamed mucous membranes of the tubuli uriniferi, as farther explained in its place. This torpor, or paralysis of the secretory vessels of the kidneys, like that of the liver, owes its origin to their being previously habituated to too great stimulus; which in this country is generally owing to the alcohol contained in ale or wine; and hence must be registered amongst the diseases owing to inebriety; though it may be caused by whatever occasionally inflames the kidney; as too violent riding on horseback, or the cold from a damp bed, or by sleeping on the cold ground; or perhaps by drinking in general too little aqueous fluids. III. I shall conclude this section on the diseases of the liver induced by spirituous liquors, with the well known story of Prometheus, which seems indeed to have been invented by physicians in those ancient times, when all things were clothed in hieroglyphic, or in fable. Prometheus was painted as stealing fire from heaven, which might well represent the inflammable spirit produced by fermentation; which may be said to animate or enliven the man of clay: whence the conquests of Bacchus, as well as the temporary mirth and noise of his devotees. But the after punishment of those, who steal this accursed fire, is a vulture gnawing the liver; and well allegorises the poor inebriate lingering for years under painful hepatic diseases. When the expediency of laying a further tax on the distillation of spirituous liquors from grain was canvassed before the House of Commons some years ago, it was said of the distillers, with great truth, "_They take the bread from the people, and convert it into poison!_" Yet is this manufactory of disease permitted to continue, as appears by its paying into the treasury above 900,000l. near a million of money annually. And thus, under the names of rum, brandy, gin, whisky, usquebaugh, wine, cyder, beer, and porter, alcohol is become the bane of the Christian world, as opium of the Mahometan. Evoe! parce, liber? Parce, gravi metuende thirso!--Hor. * * * * * SECT. XXXI. OF TEMPERAMENTS. I. _The temperament of decreased irritability known by weak pulse, large pupils of the eyes, cold extremities. Are generally supposed to be too irritable. Bear pain better than labour. Natives of North-America contrasted with those upon the coast of Africa. Narrow and broad shouldered people. Irritable constitutions bear labour better than pain._ II. _Temperament of increased sensibility. Liable to intoxication, to inflammation, hæmoptoe, gutta serena, enthusiasm, delirium, reverie. These constitutions are indolent to voluntary exertions, and dull to irritations. The natives of South-America, and brute animals of this temperament._ III. _Of increased voluntarity; these are subject to locked jaw, convulsions, epilepsy, mania. Are very active, bear cold, hunger, fatigue. Are suited to great exertions. This temperament distinguishes mankind from other animals._ IV. _Of increased association. These have great memories, are liable to quartan agues, and stronger sympathies of parts with each other._ V. _Change of temperaments into one another._ Antient writers have spoken much of temperaments, but without sufficient precision. By temperament of the system should be meant a permanent predisposition to certain classes of diseases: without this definition a temporary predisposition to every distinct malady might be termed a temperament. There are four kinds of constitution, which permanently deviate from good health, and are perhaps sufficiently marked to be distinguished from each other, and constitute the temperaments or predispositions to the irritative, sensitive, voluntary, and associate classes of diseases. I. _The Temperament of decreased Irritability._ The diseases, which are caused by irritation, most frequently originate from the defect of it; for those, which are immediately owing to the excess of it, as the hot fits of fever, are generally occasioned by an accumulation of sensorial power in consequence of a previous defect of irritation, as in the preceding cold fits of fever. Whereas the diseases, which are caused by sensation and volition, most frequently originate from the excess of those sensorial powers, as will be explained below. The temperament of decreased irritability appears from the following circumstances, which shew that the muscular fibres or organs of sense are liable to become torpid or quiescent from less defect of stimulation than is productive of torpor or quiescence in other constitutions. 1. The first is the weak pulse, which in some constitutions is at the same time quick. 2. The next most marked criterion of this temperament is the largeness of the aperture of the iris, or pupil of the eye, which has been reckoned by some a beautiful feature in the female countenance, as an indication of delicacy, but to an experienced observer it is an indication of debility, and is therefore a defect, not an excellence. The third most marked circumstance in this constitution is, that the extremities, as the hands and feet, or nose and ears, are liable to become cold and pale in situations in respect to warmth, where those of greater strength are not affected. Those of this temperament are subject to hysteric affections, nervous fevers, hydrocephalus, scrophula, and consumption, and to all other diseases of debility. Those, who possess this kind of constitution, are popularly supposed to be more irritable than is natural, but are in reality less so. This mistake has arisen from their generally having a greater quickness of pulse, as explained in Sect. XII. 1. 4. XII. 3. 3.; but this frequency of pulse is not necessary to the temperament, like the debility of it. Persons of this temperament are frequently found amongst the softer sex, and amongst narrow-shouldered men; who are said to bear labour worse, and pain better than others. This last circumstance is supposed to have prevented the natives of North America from having been made slaves by the Europeans. They are a narrow-shouldered race of people, and will rather expire under the lash, than be made to labour. Some nations of Asia have small hands, as may be seen by the handles of their scymetars; which with their narrow shoulders shew, that they have not been accustomed to so great labour with their hands and arms, as the European nations in agriculture, and those on the coasts of Africa in swimming and rowing. Dr. Maningham, a popular accoucheur in the beginning of this century, observes in his aphorisms, that broad-shouldered men procreate broad-shouldered children. Now as labour strengthens the muscles employed, and increases their bulk, it would seem that a few generations of labour or of indolence may in this respect change the form and temperament of the body. On the contrary, those who are happily possessed of a great degree of irritability, bear labour better than pain; and are strong, active, and ingenious. But there is not properly a temperament of increased irritability tending to disease, because an increased quantity of irritative motions generally induces an increase of pleasure or pain, as in intoxication, or inflammation; and then the new motions are the immediate consequences of increased sensation, not of increased irritation; which have hence been so perpetually confounded with each other. II. _Temperament of Sensibility._ There is not properly a temperament, or predisposition to disease, from decreased sensibility, since irritability and not sensibility is immediately necessary to bodily health. Hence it is the excess of sensation alone, as it is the defect of irritation, that most frequently produces disease. This temperament of increased sensibility is known from the increased activity of all those motions of the organs of sense and muscles, which are exerted in consequence of pleasure or pain, as in the beginning of drunkenness, and in inflammatory fever. Hence those of this constitution are liable to inflammatory diseases, as hepatitis; and to that kind of consumption which is hereditary, and commences with slight repeated hæmoptoe. They have high-coloured lips, frequently dark hair and dark eyes with large pupils, and are in that case subject to gutta serena. They are liable to enthusiasm, delirium, and reverie. In this last circumstance they are liable to start at the clapping of a door; because the more intent any one is on the passing current of his ideas, the greater surprise he experiences on their being dissevered by some external violence, as explained in Sect. XIX. on reverie. As in these constitutions more than the natural quantities of sensitive motions are produced by the increased quantity of sensation existing in the habit, it follows, that the irritative motions will be performed in some degree with less energy, owing to the great expenditure of sensorial power on the sensitive ones. Hence those of this temperament do not attend to slight stimulations, as explained in Sect. XIX. But when a stimulus is so great as to excite sensation, it produces greater sensitive actions of the system than in others; such as delirium or inflammation. Hence they are liable to be absent in company; sit or lie long in one posture; and in winter have the skin of their legs burnt into various colours by the fire. Hence also they are fearful of pain; covet music and sleep; and delight in poetry and romance. As the motions in consequence of sensation are more than natural, it also happens from the greater expenditure of sensorial power on them, that the voluntary motions are less easily exerted. Hence the subjects of this temperament are indolent in respect to all voluntary exertions, whether of mind or body. A race of people of this description seems to have been found by the Spaniards in the islands of America, where they first landed, ten of whom are said not to have consumed more food than one Spaniard, nor to have been capable of more than one tenth of the exertion of a Spaniard. Robertson's History.--In a state similar to this the greatest part of the animal world pass their lives, between sleep or inactive reverie, except when they are excited by the call of hunger. III. _The Temperament of increased Voluntarity._ Those of this constitution differ from both the last mentioned in this, that the pain, which gradually subsides in the first, and is productive of inflammation or delirium in the second, is in this succeeded by the exertion of the muscles or ideas, which are most frequently connected with volition; and they are thence subject to locked jaw, convulsions, epilepsy, and mania, as explained in Sect. XXXIV. Those of this temperament attend to the slightest irritations or sensations, and immediately exert themselves to obtain or avoid the objects of them; they can at the same time bear cold and hunger better than others, of which Charles the Twelfth of Sweden was an instance. They are suited and generally prompted to all great exertions of genius or labour, as their desires are more extensive and more vehement, and their powers of attention and of labour greater. It is this facility of voluntary exertion, which distinguishes men from brutes, and which has made them lords of the creation. IV. _The Temperament of increased Association._ This constitution consists in the too great facility, with which the fibrous motions acquire habits of association, and by which these associations become proportionably stronger than in those of the other temperaments. Those of this temperament are slow in voluntary exertions, or in those dependent on sensation, or on irritation. Hence great memories have been said to be attended with less sense and less imagination from Aristotle down to the present time; for by the word memory these writers only understood the unmeaning repetition of words or numbers in the order they were received, without any voluntary efforts of the mind. In this temperament those associations of motions, which are commonly termed sympathies, act with greater certainty and energy, as those between disturbed vision and the inversion of the motion of the stomach, as in sea-sickness; and the pains in the shoulder from hepatic inflammation. Add to this, that the catenated circles of actions are of greater extent than in the other constitutions. Thus if a strong vomit or cathartic be exhibited in this temperament, a smaller quantity will produce as great an effect, if it be given some weeks afterwards; whereas in other temperaments this is only to be expected, if it be exhibited in a few days after the first dose. Hence quartan agues are formed in those of this temperament, as explained in Section XXXII. on diseases from irritation, and other intermittents are liable to recur from slight causes many weeks after they have been cured by the bark. V. The first of these temperaments differs from the standard of health from defect, and the others from excess of sensorial power; but it sometimes happens that the same individual, from the changes introduced into his habit by the different seasons of the year, modes or periods of life, or by accidental diseases, passes from one of these temperaments to another. Thus a long use of too much fermented liquor produces the temperament of increased sensibility; great indolence and solitude that of decreased irritability; and want of the necessaries of life that of increased voluntarity. * * * * * SECT. XXXII. DISEASES OF IRRITATION. I. _Irritative fevers with strong pulse. With weak pulse. Symptoms of fever, Their source._ II. 1. _Quick pulse is owing to decreased irritability_. 2. _Not in sleep or in apoplexy._ 3. _From inanition. Owing to deficiency of sensorial power._ III. 1. _Causes of fever. From defect of heat. Heat from secretions. Pain of cold in the loins and forehead._ 2. _Great expense of sensorial power in the vital motions. Immersion in cold water. Succeeding glow of heat. Difficult respiration in cold bathing explained. Why the cold bath invigorates. Bracing and relaxation are mechanical terms._ 3. _Uses of cold bathing. Uses of cold air in fevers._ 4. _Ague fits from cold air. Whence their periodical returns._ IV. _Defect of distention a cause of fever. Deficiency of blood. Transfusion of blood._ V. 1. _Defect of momentum of the blood from mechanic stimuli. 2. Air injected into the blood-vessels._ 3. _Exercise increases the momentum of the blood._ 4. _Sometimes bleeding increases the momentum of it._ VI. _Influence of the sun and moon on diseases. The chemical stimulus of the blood. Menstruation obeys the lunations. Queries._ VII. _Quiesence of large glands a cause of fever. Swelling of the præcordia._ VIII. _Other causes of quiescence, as hunger, bad air, fear, anxiety._ IX. 1. _Symptoms of the cold fit._ 2. _Of the hot fit._ 3. _Second cold fit why._ 4. _Inflammation introduced, or delirium, or stupor._ X. _Recapitulation. Fever not an effort of nature to relieve herself. Doctrine of spasm._ I. When the contractile sides of the heart and arteries perform a greater number of pulsations in a given time, and move through a greater area at each pulsation, whether these motions are occasioned by the stimulus of the acrimony or quantity of the blood, or by their association with other irritative motions, or by the increased irritability of the arterial system, that is, by an increased quantity of sensorial power, one kind of fever is produced; which may be called Synocha irritativa, or Febris irritativa pulsu forti, or irritative fever with strong pulse. When the contractile sides of the heart and arteries perform a greater number of pulsations in a given time, but move through a much less area at each pulsation, whether these motions are occasioned by defect of their natural stimuli, or by the defect of other irritative motions with which they are associated, or from the inirritability of the arterial system, that is, from a decreased quantity of sensorial power, another kind of fever arises; which may be termed, Typhus irritativus, or Febris irritativa pulsu debili, or irritative fever with weak pulse. The former of these fevers is the synocha of nosologists, and the latter the typhus mitior, or nervous fever. In the former there appears to be an increase of sensorial power, in the latter a deficiency of it; which is shewn to be the immediate cause of strength and weakness, as defined in Sect. XII. 1. 3. It should be added, that a temporary quantity of strength or debility may be induced by the defect or excess of stimulus above what is natural; and that in the same fever _debility always exists during the cold fit, though strength does not always exist during the hot fit._ These fevers are always connected with, and generally induced by, the disordered irritative motions of the organs of sense, or of the intestinal canal, or of the glandular system, or of the absorbent system; and hence are always complicated with some or many of these disordered motions, which are termed the symptoms of the fever, and which compose the great variety in these diseases. The irritative fevers both with strong and with weak pulse, as well as the sensitive fevers with strong and with weak pulse, which are to be described in the next section, are liable to periodical remissions, and then they take the name of intermittent fevers, and are distinguished by the periodical times of their access. II. For the better illustration of the phenomena of irritative fevers we must refer the reader to the circumstances of irritation explained in Sect. XII. and shall commence this intricate subject by speaking of the quick pulse, and proceed by considering many of the causes, which either separately or in combination most frequently produce the cold fits of fevers. 1. If the arteries are dilated but to half their usual diameters, though they contract twice as frequently in a given time, they will circulate only half their usual quantity of blood: for as they are cylinders, the blood which they contain must be as the squares of their diameters. Hence when the pulse becomes quicker and smaller in the same proportion, the heart and arteries act with less energy than in their natural state. See Sect. XII. 1. 4. That this quick small pulse is owing to want of irritability, appears, first, because it attends other symptoms of want of irritability; and, secondly, because on the application of a stimulus greater than usual, it becomes slower and larger. Thus in cold fits of agues, in hysteric palpitations of the heart, and when the body is much exhausted by hæmorrhages, or by fatigue, as well as in nervous fevers, the pulse becomes quick and small; and secondly, in all those cases if an increase of stimulus be added, by giving a little wine or opium; the quick small pulse becomes slower and larger, as any one may easily experience on himself, by counting his pulse after drinking one or two glasses of wine, when he is faint from hunger or fatigue. Now nothing can so strongly evince that this quick small pulse is owing to defect of irritability, than that an additional stimulus, above what is natural, makes it become slower and larger immediately: for what is meant by a defect of irritability, but that the arteries and heart are not excited into their usual exertions by their usual quantity of stimulus? but if you increase the quantity of stimulus, and they immediately act with their usual energy, this proves their previous want of their natural degree of irritability. Thus the trembling hands of drunkards in a morning become steady, and acquire strength to perform their usual offices, by the accustomed stimulus of a glass or two of brandy. 2. In sleep and in apoplexy the pulse becomes slower, which is not owing to defect of irritability, for it is at the same time larger; and thence the quantity of the circulation is rather increased than diminished. In these cases the organs of sense are closed, and the voluntary power is suspended, while the motions dependent on internal irritations, as those of digestion and secretion, are carried on with more than their usual vigour; which has led superficial observers to confound these cases with those arising from want of irritability. Thus if you lift up the eyelid of an apoplectic patient, who is not actually dying, the iris will, as usual, contract itself, as this motion is associated with the stimulus of light; but it is not so in the last stages of nervous fevers, where the pupil of the eye continues expanded in the broad day-light: in the former case there is a want of voluntary power, in the latter a want of irritability. Hence also those constitutions which are deficient in quantity of irritability, and which possess too great sensibility, as during the pain of hunger, of hysteric spasms, or nervous headachs, are generally supposed to have too much irritability; and opium, which in its due dose is a most powerful stimulant, is erroneously called a sedative; because by increasing the irritative motions it decreases the pains arising from defect of them. Why the pulse should become quicker both from an increase of irritation, as in the synocha irritativa, or irritative fever with strong pulse; and from the decrease of it, as in the typhus irritativus, or irritative fever with weak pulse; seems paradoxical. The former circumstance needs no illustration; since if the stimulus of the blood, or the irritability of the sanguiferous system be increased, and the strength of the patient not diminished, it is plain that the motions must be performed quicker and stronger. In the latter circumstance the weakness of the muscular power of the heart is soon over-balanced by the elasticity of the coats of the arteries, which they possess besides a muscular power of contraction; and hence the arteries are distended to less than their usual diameters. The heart being thus stopped, when it is but half emptied, begins sooner to dilate again; and the arteries being dilated to less than their usual diameters, begin so much sooner to contract themselves; insomuch, that in the last stages of fevers with weakness the frequency of pulsation of the heart and arteries becomes doubled; which, however, is never the case in fevers with strength, in which they seldom exceed 118 or 120 pulsations in a minute. It must be added, that in these cases, while the pulse is very small and very quick, the heart often feels large, and labouring to one's hand; which coincides with the above explanation, shewing that it does not completely empty itself. 3. In cases however of debility from paucity of blood, as in animals which are bleeding to death in the slaughter-house, the quick pulsations of the heart and arteries may be owing to their not being distended to more than half their usual diastole; and in consequence they must contract sooner, or more frequently, in a given time. As weak people are liable to a deficient quantity of blood, this cause may occasionally contribute to quicken the pulse in fevers with debility, which may be known by applying one's hand upon the heart as above; but the principal cause I suppose to consist in the diminution of sensorial power. When a muscle contains, or is supplied with but little sensorial power, its contraction soon ceases, and in consequence may soon recur, as is seen in the trembling hands of people weakened by age or by drunkenness. See Sect. XII. 1. 4. XII. 3. 4. It may nevertheless frequently happen, that both the deficiency of stimulus, as where the quantity of blood is lessened (as described in No. 4. of this section), and the deficiency of sensorial power, as in those of the temperament of irritability, described in Sect. XXXI. occur at the same time; which will thus add to the quickness of the pulse and to the danger of the disease. III. 1. A certain degree of heat is necessary to muscular motion, and is, in consequence, essential to life. This is observed in those animals and insects which pass the cold season in a torpid state, and which revive on being warmed by the fire. This necessary stimulus of heat has two sources; one from the fluid atmosphere of heat, in which all things are immersed, and the other from the internal combinations of the particles, which form the various fluids, which are produced in the extensive systems of the glands. When either the external heat, which surrounds us, or the internal production of it, becomes lessened to a certain degree, the pain of cold is perceived. This pain of cold is experienced most sensibly by our teeth, when ice is held in the mouth; or by our whole system after having been previously accustomed to much warmth. It is probable, that this pain does not arise from the mechanical or chemical effects of a deficiency of heat; but that, like the organs of sense by which we perceive hunger and thirst, this sense of heat suffers pain, when the stimulus of its object is wanting to excite the irritative motions of the organ; that is, when the sensorial power becomes too much accumulated in the quiescent fibres. See Sect. XII. 5. 3. For as the peristaltic motions of the stomach are lessened, when the pain of hunger is great, so the action of the cutaneous capillaries are lessened during the pain of cold; as appears by the paleness of the skin, as explained in Sect. XIV. 6. on the production of ideas. The pain in the small of the back and forehead in the cold fits of the ague, in nervous hemicrania, and in hysteric paroxysms, when all the irritative motions are much impaired, seems to arise from this cause; the vessels of these membranes or muscles become torpid by their irritative associations with other parts of the body, and thence produce less of their accustomed secretions, and in consequence less heat is evolved, and they experience the pain of cold; which coldness may often be felt by the hand applied upon the affected part. 2. The importance of a greater or less deduction of heat from the system will be more easy to comprehend, if we first consider the great expense of sensorial power used in carrying on the vital motions; that is, which circulates, absorbs, secretes, aerates, and elaborates the whole mass of fluids with unceasing assiduity. The sensorial power, or spirit of animation, used in giving perpetual and strong motion to the heart, which overcomes the elasticity and vis inertiæ of the whole arterial system; next the expense of sensorial power in moving with great force and velocity the innumerable trunks and ramifications of the arterial system; the expense of sensorial power in circulating the whole mass of blood through the long and intricate intortions of the very fine vessels, which compose the glands and capillaries; then the expense of sensorial power in the exertions of the absorbent extremities of all the lacteals, and of all the lymphatics, which open their mouths on the external surface of the skin, and on the internal surfaces of every cell or interstice of the body; then the expense of sensorial power in the venous absorption, by which the blood is received from the capillary vessels, or glands, where the arterial power ceases, and is drank up, and returned to the heart; next the expense of sensorial power used by the muscles of respiration in their office of perpetually expanding the bronchia, or air-vessels, of the lungs; and lastly in the unceasing peristaltic motions of the stomach and whole system of intestines, and in all the secretions of bile, gastric juice, mucus, perspirable matter, and the various excretions from the system. If we consider the ceaseless expense of sensorial power thus perpetually employed, it will appear to be much greater in a day than all the voluntary exertions of our muscles and organs of sense consume in a week; and all this without any sensible fatigue! Now, if but a part of these vital motions are impeded, or totally stopped for but a short time, we gain an idea, that there must be a great accumulation of sensorial power; as its production in these organs, which are subject to perpetual activity, is continued during their quiescence, and is in consequence accumulated. While, on the contrary, where those vital organs act too forcibly by increase of stimulus without a proportionally-increased production of sensorial power in the brain, it is evident, that a great deficiency of action, that is torpor, must soon follow, as in fevers; whereas the locomotive muscles, which act only by intervals, are neither liable to so great accumulation of sensorial power during their times of inactivity, nor to so great an exhaustion of it during their times of action. Thus, on going into a very cold bath, suppose at 33 degrees of heat on Fahrenheit's scale, the action of the subcutaneous capillaries, or glands, and of the mouths of the cutaneous absorbents is diminished, or ceases for a time. Hence less or no blood passes these capillaries, and paleness succeeds. But soon after emerging from the bath, a more florid colour and a greater degree of heat is generated on the skin than was possessed before immersion; for the capillary glands, after this quiescent state, occasioned by the want of stimulus, become more irritable than usual to their natural stimuli, owing to the accumulation of sensorial power, and hence a greater quantity of blood is transmitted through them, and a greater secretion of perspirable matter; and, in consequence, a greater degree of heat succeeds. During the continuance in cold water the breath is cold, and the act of respiration quick and laborious; which have generally been ascribed to the obstruction of the circulating fluid by a spasm of the cutaneous vessels, and by a consequent accumulation of blood in the lungs, occasioned by the pressure as well as by the coldness of the water. This is not a satisfactory account of this curious phænomenon, since at this time the whole circulation is less, as appears from the smallness of the pulse and coldness of the breath; which shew that less blood passes through the lungs in a given time; the same laborious breathing immediately occurs when the paleness of the skin is produced by fear, where no external cold or pressure are applied. The minute vessels of the bronchia, through which the blood passes from the arterial to the venal system, and which correspond with the cutaneous capillaries, have frequently been exposed to cold air, and become quiescent along with those of the skin; and hence their motions are so associated together, that when one is affected either with quiescence or exertion, the other sympathizes with it, according to the laws of irritative association. See Sect. XXVII. 1. on hæmorrhages. Besides the quiescence of the minute vessels of the lungs, there are many other systems of vessels which become torpid from their irritative associations with those of the skin, as the absorbents of the bladder and intestines; whence an evacuation of pale urine occurs, when the naked skin is exposed only to the coldness of the atmosphere; and sprinkling the naked body with cold water is known to remove even pertinacious constipation of the bowels. From the quiescence of such extensive systems of vessels as the glands and capillaries of the skin, and the minute vessels of the lungs, with their various absorbent series of vessels, a great accumulation of sensorial powers is occasioned; part of which is again expended in the increased exertion of all these vessels, with an universal glow of heat in consequence of this exertion, and the remainder of it adds vigour to both the vital and voluntary exertions of the whole day. If the activity of the subcutaneous vessels, and of those with which their actions are associated, was too great before cold immersion, as in the hot days of summer, and by that means the sensorial power was previously diminished, we see the cause why the cold bath gives such present strength; namely, by stopping the unnecessary activity of the subcutaneous vessels, and thus preventing the too great exhaustion of sensorial power; which, in metaphorical language, has been called _bracing_ the system: which is, however, a mechanical term, only applicable to drums, or musical strings: as on the contrary the word _relaxation_, when applied to living animal bodies, can only mean too small a quantity of stimulus, or too small a quantity of sensorial power; as explained in Sect. XII. 1. 3. This experiment of cold bathing presents us with a simple fever-fit; for the pulse is weak, small, and quick during the cold immersion; and becomes strong, full, and quick during the subsequent glow of heat; till in a few minutes these symptoms subside, and the temporary fever ceases. In those constitutions where the degree of inirritability, or of debility, is greater than natural, the coldness and paleness of the skin with the quick and weak pulse continue a long time after the patient leaves the bath; and the subsequent heat approaches by unequal flushings, and he feels himself disordered for many hours. Hence the bathing in a cold spring of water, where the heat is but forty-eight degrees on Fahrenheit's thermometer, much disagrees with those of weak or inirritable habits of body; who possess so little sensorial power, that they cannot without injury bear to have it diminished even for a short time; but who can nevertheless bear the more temperate coldness of Buxton bath, which is about eighty degrees of heat, and which strengthens them, and makes them by habit less liable to great quiescence from small variations of cold, and thence less liable to be disordered by the unavoidable accidents of life. Hence it appears, why people of these inirritable constitutions, which is another expression for sensorial deficiency, are often much injured by bathing in a cold spring of water; and why they should continue but a very short time in baths, which are colder than their bodies; and should gradually increase both the degree of coldness of the water, and the time of their continuance in it, if they would obtain salutary effects from cold immersions. See Sect. XII. 2. 1. On the other hand, in all cases where the heat of the external surface of the body, or of the internal surface of the lungs, is greater than natural, the use of exposure to cool air may be deduced. In fever-fits attended with strength, that is with great quantity of sensorial power, it removes the additional stimulus of heat from the surfaces above mentioned, and thus prevents their excess of useless motion; and in fever-fits attended with debility, that is with a deficiency of the quantity of sensorial power, it prevents the great and dangerous waste of sensorial power expended in the unnecessary increase of the actions of the glands and capillaries of the skin and lungs. 4. In the same manner, when any one is long exposed to very cold air, a quiescence is produced of the cutaneous and pulmonary capillaries and absorbents, owing to the deficiency of their usual stimulus of heat; and this quiescence of so great a quantity of vessels affects, by irritative association, the whole absorbent and glandular system, which becomes in a greater or less degree quiescent, and a cold fit of fever is produced. If the deficiency of the stimulus of heat is very great, the quiescence becomes so general as to extinguish life, as in those who are frozen to death. If the deficiency of heat be in less degree, but yet so great as in some measure to disorder the system, and should occur the succeeding day, it will induce a greater degree of quiescence than before, from its acting in concurrence with the period of the diurnal circle of actions, explained in Sect. XXXVI. Hence from a small beginning a greater and greater degree of quiescence may be induced, till a complete fever-fit is formed; and which will continue to recur at the periods by which it was produced. See Sect. XVII. 3. 6. If the degree of quiescence occasioned by defect of the stimulus of heat be very great, it will recur a second time by a slighter cause, than that which first induced it. If the cause, which induces the second fit of quiescence, recurs the succeeding day, the quotidian fever is produced; if not till the alternate day, the tertian fever; and if not till after seventy-two hours from the first fit of quiescence, the quartan fever is formed. This last kind of fever recurs less frequently than the other, as it is a disease only of those of the temperament of associability, as mentioned in Sect. XXXI.; for in other constitutions the capability of forming a habit ceases, before the new cause of quiescence is again applied, if that does not occur sooner than in seventy-two hours. And hence those fevers, whose cause is from cold air of the night or morning, are more liable to observe the solar day in their periods; while those from other causes frequently observe the lunar day in their periods, their paroxysms returning near an hour later every day, as explained in Sect. XXXVI. IV. Another frequent cause of the cold fits of fever is the defect of the stimulus of distention. The whole arterial system would appear, by the experiments of Haller, to be irritable by no other stimulus, and the motions of the heart and alimentary canal are certainly in some measure dependant on the same cause. See Sect. XIV. 7. Hence there can be no wonder, that the diminution of distention should frequently induce the quiescence, which constitutes the beginning of fever-fits. Monsieur Leiutaud has judiciously mentioned the deficiency of the quantity of blood amongst the causes of diseases, which he says is frequently evident in dissections: fevers are hence brought on by great hæmorrhages, diarrhoeas, or other evacuations; or from the continued use of diet, which contains but little nourishment; or from the exhaustion occasioned by violent fatigue, or by those chronic diseases in which the digestion is much impaired; as where the stomach has been long affected with the gout or schirrus; or in the paralysis of the liver, as described in Sect. XXX. Hence a paroxysm of gout is liable to recur on bleeding or purging; as the torpor of some viscus, which precedes the inflammation of the foot, is thus induced by the want of the stimulus of distention. And hence the extremities of the body, as the nose and fingers, are more liable to become cold, when we have long abstained from food; and hence the pulse is increased both in strength and velocity above the natural standard after a full meal by the stimulus of distention. However, this stimulus of distention, like the stimulus of heat above described, though it contributes much to the due action not only of the heart, arteries, and alimentary canal, but seems necessary to the proper secretion of all the various glands; yet perhaps it is not the sole cause of any of these numerous motions: for as the lacteals, cutaneous absorbents, and the various glands appear to be stimulated into action by the peculiar pungency of the fluids they absorb, so in the intestinal canal the pungency of the digesting aliment, or the acrimony of the fæces, seem to contribute, as well as their bulk, to promote the peristaltic motions; and in the arterial system, the momentum of the particles of the circulating blood, and their acrimony, stimulate the arteries, as well as the distention occasioned by it. Where the pulse is small this defect of distention is present, and contributes much to produce the febris irritativa pulsu debili, or irritative fever with weak pulse, called by modern writers nervous fever, as a predisponent cause. See Sect. XII. 1. 4. Might not the transfusion of blood, suppose of four ounces daily from a strong man, or other healthful animal, as a sheep or an ass, be used in the early state of nervous or putrid fevers with great prospect of success? V. 1. The defect of the momentum of the particles of the circulating blood is another cause of the quiescence, with which the cold fits of fever commence. This stimulus of the momentum of the progressive particles of the blood does not act over the whole body like those of heat and distention above described, but is confined to the arterial system; and differs from the stimulus of the distention of the blood, as much as the vibration of the air does from the currents of it. Thus are the different organs of our bodies stimulated by four different mechanic properties of the external world: the sense of touch by the pressure of solid bodies so as to distinguish their figure; the muscular system by the distention, which they occasion; the internal surface of the arteries, by the momentum of their moving particles; and the auditory nerves, by the vibration of them: and these four mechanic properties are as different from each other as the various chemical ones, which are adapted to the numerous glands, and to the other organs of sense. 2. The momentum of the progressive particles of blood is compounded of their velocity and their quantity of matter: hence whatever circumstances diminish either of these without proportionally increasing the other, and without superadding either of the general stimuli of heat or distention, will tend to produce a quiescence of the arterial system, and from thence of all the other irritative motions, which are connected with it. Hence in all those constitutions or diseases where the blood contains a greater proportion of serum, which is the lightest part of its composition, the pulsations of the arteries are weaker, as in nervous fevers, chlorosis, and hysteric complaints; for in these cases the momentum of the progressive particles of blood is less: and hence, where the denser parts of its composition abound, as the red part of it, or the coagulable lymph, the arterial pulsations are stronger; as in those of robust health, and in inflammatory diseases. That this stimulus of the momentum of the particles of the circulating fluid is of the greatest consequence to the arterial action, appears from the experiment of injecting air into the blood vessels, which seems to destroy animal life from the want of this stimulus of momentum; for the distention of the arteries is not diminished by it, it possesses no corrosive acrimony, and is less liable to repass the valves than the blood itself; since air-valves in all machinery require much less accuracy of construction than those which are opposed to water. 3. One method of increasing the velocity of the blood, and in consequence the momentum of its particles, is by the exercise of the body, or by the friction of its surface: so, on the contrary, too great indolence contributes to decrease this stimulus of the momentum of the particles of the circulating blood, and thus tends to induce quiescence; as is seen in hysteric cases, and chlorosis, and the other diseases of sedentary people. 4. The velocity of the particles of the blood in certain circumstances is increased by venesection, which, by removing a part of it, diminishes the resistance to the motion of the other part, and hence the momentum of the particles of it is increased. This may be easily understood by considering it in the extreme, since, if the resistance was greatly increased, so as to overcome the propelling power, there could be no velocity, and in consequence no momentum at all. From this circumstance arises that curious phænomenon, the truth of which I have been more than once witness to, that venesection will often instantaneously relieve those nervous pains, which attend the cold periods of hysteric, asthmatic, or epileptic diseases; and that even where large doses of opium have been in vain exhibited. In these cases the pulse becomes stronger after the bleeding, and the extremities regain their natural warmth; and an opiate then given acts with much more certain effect. VI. There is another cause, which seems occasionally to induce quiescence into some part of our system, I mean the influence of the sun and moon; the attraction of these luminaries, by decreasing the gravity of the particles of the blood, cannot affect their momentum, as their vis inertiæ remains the same; but it may nevertheless produce some chemical change in them, because whatever affects the general attractions of the particles of matter may be supposed from analogy to affect their specific attractions or affinities: and thus the stimulus of the particles of blood may be diminished, though not their momentum. As the tides of the sea obey the southing and northing of the moon (allowing for the time necessary for their motion, and the obstructions of the shores), it is probable, that there are also atmospheric tides on both sides of the earth, which to the inhabitants of another planet might so deflect the light as to resemble the ring of Saturn. Now as these tides of water, or of air, are raised by the diminution of their gravity, it follows, that their pressure on the surface of the earth is no greater than the pressure of the other parts of the ocean, or of the atmosphere, where no such tides exist; and therefore that they cannot affect the mercury in the barometer. In the same manner, the gravity of all other terrestrial bodies is diminished at the times of the southing and northing of the moon, and that in a greater degree when this coincides with the southing and northing of the sun, and this in a still greater degree about the times of the equinoxes. This decrease of the gravity of all bodies during the time the moon passes our zenith or nadir might possibly be shewn by the slower vibrations of a pendulum, compared with a spring clock, or with astronomical observation. Since a pendulum of a certain length moves slower at the line than near the poles, because the gravity being diminished and the vis inertiæ continuing the same, the motive power is less, but the resistance to be overcome continues the same. The combined powers of the lunar and solar attraction is estimated by Sir Isaac Newton not to exceed one 7,868,850th part of the power of gravitation, which seems indeed but a small circumstance to produce any considerable effect on the weight of sublunary bodies, and yet this is sufficient to raise the tides at the equator above ten feet high; and if it be considered, what small impulses of other bodies produce their effects on the organs of sense adapted to the perception of them, as of vibration on the auditory nerves, we shall cease to to be surprised, that so minute a diminution in the gravity of the particles of blood should so far affect their chemical changes, or their stimulating quality, as, joined with other causes, sometimes to produce the beginnings of diseases. Add to this, that if the lunar influence produces a very small degree of quiescence at first, and if that recurs at certain periods even with less power to produce quiescence than at first, yet the quiescence will daily increase by the acquired habit acting at the same time, till at length so great a degree of quiescence is induced as to produce phrensy, canine madness, epilepsy, hysteric pains or cold fits of fever, instances of many of which are to be found in Dr. Mead's work on this subject. The solar influence also appears daily in several diseases; but as darkness, silence, sleep, and our periodical meals mark the parts of the solar circle of actions, it is sometimes dubious to which of these the periodical returns of these diseases are to be ascribed. As far as I have been able to observe, the periods of inflammatory diseases observe the solar day; as the gout and rheumatism have their greatest quiescence about noon and midnight, and their exacerbations some hours after; as they have more frequently their immediate cause from cold air, inanition, or fatigue, than from the effects of lunations: whilst the cold fits of hysteric patients, and those in nervous fevers, more frequently occur twice a day, later by near half an hour each time, according to the lunar day; whilst some fits of intermittents, which are undisturbed by medicines, return at regular solar periods, and others at lunar ones; which may, probably, be owing to the difference of the periods of those external circumstances of cold, inanition, or lunation, which immediately caused them. We must, however, observe, that the periods of quiescence and exacerbation in diseases do not always commence at the times of the syzygies or quadratures of the moon and sun, or at the times of their passing the zenith or nadir; but as it is probable, that the stimulus of the particles of the circumfluent blood is gradually diminished from the time of the quadratures to that of the syzygies, the quiescence may commence at any hour, when co-operating with other causes of quiescence, it becomes great enough to produce a disease: afterwards it will continue to recur at the same period of the lunar or solar influence; the same cause operating conjointly with the acquired habit, that is with the catenation of this new motion with the dissevered links of the lunar or solar circles of animal action. In this manner the periods of menstruation obey the lunar month with great exactness in healthy patients (and perhaps the venereal orgasm in brute animals does the same), yet these periods do not commence either at the syzygies or quadratures of the lunations, but at whatever time of the lunar periods they begin, they observe the same in their returns till some greater cause disturbs them. Hence, though the best way to calculate the time of the expected returns of the paroxysms of periodical diseases is to count the number of hours between the commencement of the two preceding fits, yet the following observations may be worth attending to, when we endeavour to prevent the returns of maniacal or epileptic diseases; whose periods (at the beginning of them especially) frequently observe the syzygies of the moon and sun, and particularly about the equinox. The greatest of the two tides happening in every revolution of the moon, is that when the moon approaches nearest to the zenith or nadir; for this reason, while the sun is in the northern signs, that is during the vernal and summer months, the greater of the two diurnal tides in our latitude is that, when the moon is above the horizon; and when the sun is in the southern signs, or during the autumnal and winter months, the greater tide is that, which arises when the moon is below the horizon: and as the sun approaches somewhat nearer the earth in winter than in summer, the greatest equinoctial tides are observed to be a little before the vernal equinox, and a little after the autumnal one. Do not the cold periods of lunar diseases commence a few hours before the southing of the moon during the vernal and summer months, and before the northing of the moon during the autumnal and winter months? Do not palsies and apoplexies, which occur about the equinoxes, happen a few days before the vernal equinoctial lunation, and after the autumnal one? Are not the periods of those diurnal diseases more obstinate, that commence many hours before the southing or northing of the moon, than of those which commence at those times? Are not those palsies and apoplexies more dangerous which commence many days before the syzygies of the moon, than those which happen at those times? See Sect. XXXVI. on the periods of diseases. VII. Another very frequent cause of the cold fit of fever is the quiescence of some of those large congeries of glands, which compose the liver, spleen, or pancreas; one or more of which are frequently so enlarged in the autumnal intermittents as to be perceptible to the touch externally, and are called by the vulgar ague-cakes. As these glands are stimulated into action by the specific pungency of the fluids, which they absorb, the general cause of their quiescence seems to be the too great insipidity of the fluids of the body, co-operating perhaps at the same time with other general causes of quiescence. Hence, in marshy countries at cold seasons, which have succeeded hot ones, and amongst those, who have lived on innutritious and unstimulating diet, these agues are most frequent. The enlargement of these quiescent viscera, and the swelling of the præcordia in many other fevers, is, most probably, owing to the same cause; which may consist in a general deficiency of the production of sensorial power, as well as in the diminished stimulation of the fluids; and when the quiescence of so great a number of glands, as constitute one of those large viscera, commences, all the other irritative motions are affected by their connection with it, and the cold fit of fever is produced. VIII. There are many other causes, which produce quiescence of some part of the animal system, as fatigue, hunger, thirst, bad diet, disappointed love, unwholesome air, exhaustion from evacuations, and many others; but the last cause, that we shall mention, as frequently productive of cold fits of fever, is fear or anxiety of mind. The pains, which we are first and most generally acquainted with, have been produced by defect of some stimulus; thus, soon after our nativity we become acquainted with the pain from the coldness of the air, from the want of respiration, and from the want of food. Now all these pains occasioned by defect of stimulus are attended with quiescence of the organ, and at the same time with a greater or less degree of quiescence of other parts of the system: thus, if we even endure the pain of hunger so as to miss one meal instead of our daily habit of repletion, not only the peristaltic motions of the stomach and bowels are diminished, but we are more liable to coldness of our extremities, as of our noses, and ears, and feet, than at other times. Now, as fear is originally excited by our having experienced pain, and is itself a painful affection, the same quiescence of other fibrous motions accompany it, as have been most frequently connected with this kind of pain, as explained in Sect. XVI. 8. 1. as the coldness and paleness of the skin, trembling, difficult respiration, indigestion, and other symptoms, which contribute to form the cold fit of fevers. Anxiety is fear continued through a longer time, and, by producing chronical torpor of the system, extinguishes life slowly, by what is commonly termed a broken heart. IX. 1. We now step forwards to consider the other symptoms in consequence of the quiescence which begins the fits of fever. If by any of the circumstances before described, or by two or more of them acting at the same time, a great degree of quiescence is induced on any considerable part of the circle of irritative motions, the whole class of them is more or less disturbed by their irritative associations. If this torpor be occasioned by a deficient supply of sensorial power, and happens to any of those parts of the system, which are accustomed to perpetual activity, as the vital motions, the torpor increases rapidly, because of the great expenditure of sensorial power by the incessant activity of those parts of the system, as shewn in No. 3. 2. of this Section. Hence a deficiency of all the secretions succeeds, and as animal heat is produced in proportion to the quantity of those secretions, the coldness of the skin is the first circumstance, which is attended to. Dr. Martin asserts, that some parts of his body were warmer than natural in the cold fit of fever; but it is certain, that those, which are uncovered, as the fingers, and nose, and ears, are much colder to the touch, and paler in appearance. It is possible, that his experiments were made at the beginning of the subsequent hot fits; which commence with partial distributions of heat, owing to some parts of the body regaining their natural irritability sooner than others. From the quiescence of the anastomosing capillaries a paleness of the skin succeeds, and a less secretion of the perspirable matter; from the quiescence of the pulmonary capillaries a difficulty of respiration arises; and from the quiescence of the other glands less bile, less gastric and pancreatic juice, are secreted into the stomach and intestines, and less mucus and saliva are poured into the mouth; whence arises the dry tongue, costiveness, dry ulcers, and paucity of urine. From the quiescence of the absorbent system arises the great thirst, as less moisture is absorbed from the atmosphere. The absorption from the atmosphere was observed by Dr. Lyster to amount to eighteen ounces in one night, above what he had at the same time insensibly perspired. See Langrish. On the same account the urine is pale, though in small quantity, for the thinner part is not absorbed from it; and when repeated ague-fits continue long, the legs swell from the diminished absorption of the cellular absorbents. From the quiescence of the intestinal canal a loss of appetite and flatulencies proceed. From the partial quiescence of the glandular viscera a swelling and tension about the præcordia becomes sensible to the touch; which is occasioned by the delay of the fluids from the defect of venous or lymphatic absorption. The pain of the forehead, and of the limbs, and of the small of the back, arises from the quiescence of the membranous fascia, or muscles of those parts, in the same manner as the skin becomes painful, when the vessels, of which it is composed, become quiescent from cold. The trembling in consequence of the pain of coldness, the restlessness, and the yawning, and stretching of the limbs, together with the shuddering, or rigours, are convulsive motions; and will be explained amongst the diseases of volition; Sect. XXXIV. Sickness and vomiting is a frequent symptom in the beginnings of fever-fits, the muscular fibres of the stomach share the general torpor and debility of the system; their motions become first lessened, and then stop, and then become retrograde; for the act of vomiting, like the globus hystericus and the borborigmi of hypochondriasis, is always a symptom of debility, either from want of stimulus, as in hunger; or from want of sensorial power, as after intoxication; or from sympathy with some other torpid irritative motions, as in the cold fits of ague. See Sect. XII. 5. 5. XXIX. 11. and XXXV. 1. 3. where this act of vomiting is further explained. The small pulse, which is said by some writers to be slow at the commencement of ague-fits, and which is frequently trembling and intermittent, is owing to the quiescence of the heart and arterial system, and to the resistance opposed to the circulating fluid from the inactivity of all the glands and capillaries. The great weakness and inability to voluntary motions, with the insensibility of the extremities, are owing to the general quiescence of the whole moving system; or, perhaps, simply to the deficient production of sensorial power. If all these symptoms are further increased, the quiescence of all the muscles, including the heart and arteries, becomes complete, and death ensues. This is, most probably, the case of those who are starved to death with cold, and of those who are said to die in Holland from long skaiting on their frozen canals. 2. As soon as this general quiescence of the system ceases, either by the diminution of the cause, or by the accumulation of sensorial power, (as in syncope, Sect. XII. 7. 1.) which is the natural consequence of previous quiescence, the hot fit commences. Every gland of the body is now stimulated into stronger action than is natural, as its irritability is increased by accumulation of sensorial power during its late quiescence, a superabundance of all the secretions is produced, and an increase of heat in consequence of the increase of these secretions. The skin becomes red, and the perspiration great, owing to the increased action of the capillaries during the hot part of the paroxysm. The secretion of perspirable matter is perhaps greater during the hot fit than in the sweating fit which follows; but as the absorption of it also is greater, it does not stand on the skin in visible drops: add to this, that the evaporation of it also is greater, from the increased heat of the skin. But at the decline of the hot fit, as the mouths of the absorbents of the skin are exposed to the cooler air, or bed-clothes, these vessels sooner lose their increased activity, and cease to absorb more than their natural quantity: but the secerning vessels for some time longer, being kept warm by the circulating blood, continue to pour out an increased quantity of perspirable matter, which now stands on the skin in large visible drops; the exhalation of it also being lessened by the greater coolness of the skin, as well as its absorption by the diminished action of the lymphatics. See Class I. 1. 2. 3. The increased secretion of bile and of other fluids poured into the intestines frequently induce a purging at the decline of the hot fit; for as the external absorbent vessels have their mouths exposed to the cold air, as above mentioned, they cease to be excited into unnatural activity sooner than the secretory vessels, whose mouths are exposed to the warmth of the blood: now, as the internal absorbents sympathize with the external ones, these also, which during the hot fit drank up the thinner part of the bile, or of other secreted fluids, lose their increased activity before the gland loses its increased activity, at the decline of the hot fit; and the loose dejections are produced from the same cause, that the increased perspiration stands on the surface of the skin, from the increased absorption ceasing sooner than the increased secretion. The urine during the cold fit is in small quantity and pale, both from a deficiency of the secretion and a deficiency of the absorption. During the hot fit it is in its usual quantity, but very high coloured and turbid, because a greater quantity had been secreted by the increased action of the kidnies, and also a greater quantity of its more aqueous part had been absorbed from it in the bladder by the increased action of the absorbents; and lastly, at the decline of the hot fit it is in large quantity and less coloured, or turbid, because the absorbent vessels of the bladder, as observed above, lose their increased action by sympathy with the cutaneous ones sooner than the secretory vessels of the kidnies lose their increased activity. Hence the quantity of the sediment, and the colour of the urine, in fevers, depend much on the quantity secreted by the kidnies, and the quantity absorbed from it again in the bladder: the kinds of sediment, as the lateritious, purulent, mucous, or bloody sediments, depend on other causes. It should be observed, that if the sweating be increased by the heat of the room, or of the bed-clothes, that a paucity of turbid urine will continue to be produced, as the absorbents of the bladder will have their activity increased by their sympathy with the vessels of the skin, for the purpose of supplying the fluid expended in perspiration. The pulse becomes strong and full owing to the increased irritability of the heart and arteries, from the accumulation of sensorial power during their quiescence, and to the quickness of the return of the blood from the various glands and capillaries. This increased action of all the secretory vessels does not occur very suddenly, nor universally at the same time. The heat seems to begin about the center, and to be diffused from thence irregularly to the other parts of the system. This may be owing to the situation of the parts which first became quiescent and caused the fever-fit, especially when a hardness or tumour about the præcordia can be felt by the hand; and hence this part, in whatever viscus it is seated, might be the first to regain its natural or increased irritability. 3. It must be here noted, that, by the increased quantity of heat, and of the impulse of the blood at the commencement of the hot fit, a great increase of stimulus is induced, and is now added to the increased irritability of the system, which was occasioned by its previous quiescence. This additional stimulus of heat and momentum of the blood augments the violence of the movements of the arterial and glandular system in an increasing ratio. These violent exertions still producing more heat and greater momentum of the moving fluids, till at length the sensoral power becomes wasted by this great stimulus beneath its natural quantity, and predisposes the system to a second cold fit. At length all these unnatural exertions spontaneously subside with the increased irritability that produced them; and which was itself produced by the preceding quiescence, in the same manner as the eye, on coming from darkness into day-light, in a little time ceases to be dazzled and pained, and gradually recovers its natural degree of irritability. 4. But if the increase of irritability, and the consequent increase of the stimulus of heat and momentum, produce more violent exertions than those above described; great pain arises in some part of the moving system, as in the membranes of the brain, pleura, or joints; and new motions of the vessels are produced in consequence of this pain, which are called inflammation; or delirium or stupor arises; as explained in Sect. XXI. and XXXIII.: for the immediate effect is the same, whether the great energy of the moving organs arises from an increase of stimulus or an increase of irritability; though in the former case the waste of sensorial power leads to debility, and in the latter to health. _Recapitulation._ X. Those muscles, which are less frequently exerted, and whose actions are interrupted by sleep, acquire less accumulation of sensorial power during their quiescent state, as the muscles of locomotion. In these muscles after great exertion, that is, after great exhaustion of sensorial power, the pain of fatigue ensues; and during rest there is a renovation of the natural quantity of sensorial power; but where the rest, or quiescence of the muscle, is long continued, a quantity of sensorial power becomes accumulated beyond what is necessary; as appears by the uneasiness occasioned by want of exercise; and which in young animals is one cause exciting them into action, as is seen in the play of puppies and kittens. But when those muscles, which are habituated to perpetual actions, as those of the stomach by the stimulus of food, those of the vessels of the skin by the stimulus of heat, and those which constitute the arteries and glands by the stimulus of the blood, become for a time quiescent, from the want of their appropriated stimuli, or by their associations with other quiescent parts of the system; a greater accumulation of sensorial power is acquired during their quiescence, and a greater or quicker exhaustion of it is produced during their increased action. This accumulation of sensorial power from deficient action, if it happens to the stomach from want of food, occasions the pain of hunger; if it happens to the vessels of the skin from want of heat, it occasions the pain of cold; and if to the arterial system from the want of its adapted stimuli, many disagreeable sensations are occasioned, such as are experienced in the cold fits of intermittent fevers, and are as various, as there are glands or membranes in the system, and are generally termed universal uneasiness. When the quiescence of the arterial system is not owing to defect of stimulus as above, but to the defective quantity of sensorial power, as in the commencement of nervous fever, or irritative fever with weak pulse, a great torpor of this system is quickly induced; because both the irritation from the stimulus of the blood, and the association of the vascular motions with each other, continue to excite the arteries into action, and thence quickly exhaust the ill-supplied vascular muscles; for to rest is death; and therefore those vascular muscles continue to proceed, though with feebler action, to the extreme of weariness or faintness: while nothing similar to this affects the locomotive muscles, whose actions are generally caused by volition, and not much subject either to irritation or to other kinds of associations besides the voluntary ones, except indeed when they are excited by the lash of slavery. In these vascular muscles, which are subject to perpetual action, and thence liable to great accumulation of sensorial power during their quiescence from want of stimulus, a great increase of activity occurs, either from the renewal of their accustomed stimulus, or even from much less quantities of stimulus than usual. This increase of action constitutes the hot fit of fever, which is attended with various increased secretions, with great concomitant heat, and general uneasiness. The uneasiness attending this hot paroxysm of fever, or fit of exertion, is very different from that, which attends the previous cold fit, or fit of quiescence, and is frequently the cause of inflammation, as in pleurisy, which is treated of in the next section. A similar effect occurs after the quiescence of our organs of sense; those which are not subject to perpetual action, as the taste and smell, are less liable to an exuberant accumulation of sensorial power after their having for a time been inactive; but the eye, which is in perpetual action during the day, becomes dazzled, and liable to inflammation after a temporary quiescence. Where the previous quiescence has been owing to a defect of sensorial power, and not to a defect of stimulus, as in the irritative fever with weak pulse, a similar increase of activity of the arterial system succeeds, either from the usual stimulus of the blood, or from a stimulus less than usual; but as there is in general in these cases of fever with weak pulse a deficiency of the quantity of the blood, the pulse in the hot fit is weaker than in health, though it is stronger than in the cold fit, as explained in No. 2. of this section. But at the same time in those fevers, where the defect of irritation is owing to the defect of the quantity of sensorial power, as well as to the defect of stimulus, another circumstance occurs; which consists in the partial distribution of it, as appears in partial flushings, as of the face or bosom, while the extremities are cold; and in the increase of particular secretions, as of bile, saliva, insensible perspiration, with great heat of the skin, or with partial sweats, or diarrhoea. There are also many uneasy sensations attending these increased actions, which, like those belonging to the hot fit of fever with strong pulse, are frequently followed by inflammation, as in scarlet fever; which inflammation is nevertheless accompanied with a pulse weaker, though quicker, than the pulse during the remission or intermission of the paroxysms, though stronger than that of the previous cold fit. From hence I conclude, that both the cold and hot fits of fever are necessary consequences of the perpetual and incessant action of the arterial and glandular system; since those muscular fibres and those organs of sense, which are most frequently exerted, become necessarily most affected both with defect and accumulation of sensorial power: and that hence _fever-fits are not an effort of nature to relieve herself_, and that therefore they should always be prevented or diminished as much as possible, by any means which decrease the general or partial vascular actions, when they are greater, or by increasing them when they are less than in health, as described in Sect. XII. 6. 1. Thus have I endeavoured to explain, and I hope to the satisfaction of the candid and patient reader, the principal symptoms or circumstances of fever without the introduction of the supernatural power of spasm. To the arguments in favour of the doctrine of spasm it may be sufficient to reply, that in the evolution of medical as well as of dramatic catastrophe, Nec Deus intersit, nisi dignus vindice nodus inciderit.--HOR. * * * * * SECT. XXXIII. DISEASES OF SENSATION. I. 1. _Motions excited by sensation. Digestion. Generation. Pleasure of existence. Hypochondriacism._ 2. _Pain introduced. Sensitive fevers of two kinds._ 3. _Two sensorial powers exerted in sensitive fevers. Size of the blood. Nervous fevers distinguished from putrid ones. The septic and antiseptic theory._ 4. _Two kinds of delirium._ 5. _Other animals are less liable to delirium, cannot receive our contagious diseases, and are less liable to madness._ II. 1. _Sensitive motions generated._ 2. _Inflammation explained._ 3. _Its remote causes from excess of irritation, or of irritability, not from those pains which are owing to defect of irritation. New vessels produced, and much heat._ 4. _Purulent matter secreted._ 5. _Contagion explained._ 6. _Received but once._ 7. _If common matter be contagious?_ 8. _Why some contagions are received but once._ 9. _Why others may be received frequently. Contagions of small-pox and measles do not act at the same times. Two cases of such patients._ 10. _The blood from patients in the small-pox will not infect others. Cases of children thus inoculated. The variolous contagion is not received into the blood. It acts by sensitive association between the stomach and skin._ III. 1. _Absorption of solids and fluids._ 2. _Art of healing ulcers._ 3. _Mortification attended with less pain in weak people._ I. 1. As many motions of the body are excited and continued by irritations, so others require, either conjunctly with these, or separately, the pleasurable or painful sensations, for the purpose of producing them with due energy. Amongst these the business of digestion supplies us with an instance: if the food, which we swallow, is not attended with agreeable sensation, it digests less perfectly; and if very disagreeable sensation accompanies it, such as a nauseous idea, or very disgustful taste, the digestion becomes impeded; or retrograde motions of the stomach and oesophagus succeed, and the food is ejected. The business of generation depends so much on agreeable sensation, that, where the object is disgustful, neither voluntary exertion nor irritation can effect the purpose; which is also liable to be interrupted by the pain of fear or bashfulness. Besides the pleasure, which attends the irritations produced by the objects of lust and hunger, there seems to be a sum of pleasurable affection accompanying the various secretions of the numerous glands, which constitute the pleasure of life, in contradistinction to the tedium vitæ. This quantity or sum of pleasurable affection, seems to contribute to the due or energetic performance of the whole moveable system, as well that of the heart and arteries, as of digestion and of absorption; since without the due quantity of pleasurable sensation, flatulency and hypochondriacism affect the intestines, and a languor seizes the arterial pulsations and secretions; as occurs in great and continued anxiety of the mind. 2. Besides the febrile motions occasioned by irritation, described in Sect. XXXII. and termed irritative fever, it frequently happens that pain is excited by the violence of the fibrous contractions; and other new motions are then superadded, in consequence of sensation, which we shall term febris sensitiva, or sensitive fever. It must be observed, that most irritative fevers begin with a decreased exertion of irritation, owing to defect of stimulus; but that on the contrary the sensitive fevers, or inflammations, generally begin with the increased exertion of sensation, as mentioned in Sect. XXXI. on temperaments: for though the cold fit, which introduces inflammation, commences with decreased irritation, yet the inflammation itself commences in the hot fit during the increase of sensation. Thus a common pustule, or phlegmon, in a part of little sensibility does not excite an inflammatory fever; but if the stomach, intestines, or the tender substance beneath the nails, be injured, great sensation is produced, and the whole system is thrown into that kind of exertion, which constitutes inflammation. These sensitive fevers, like the irritative ones, resolve themselves into those with arterial strength, and those with arterial debility, that is with excess or defect of sensorial power; these may be termed the febris sensitiva pulsu forti, sensitive fever with strong pulse, which is the synocha, or inflammatory fever; and the febris sensitiva pulsu debili, sensitive fever with weak pulse, which is the typhus gravior, or putrid fever of some writers. 3. The inflammatory fevers, which are here termed sensitive fevers with strong pulse, are generally attended with some topical inflammation, as pleurisy, peripneumony, or rheumatism, which distinguishes them from irritative fevers with strong pulse. The pulse is strong, quick, and full; for in this fever there is great irritation, as well as great sensation, employed in moving the arterial system. The size, or coagulable lymph, which appears on the blood, is probably an increased secretion from the inflamed internal lining of the whole arterial system, the thinner part being taken away by the increased absorption of the inflamed lymphatics. The sensitive fevers with weak pulse, which are termed putrid or malignant fevers, are distinguished from irritative fevers with weak pulse, called nervous fevers, described in the last section, as the former consist of inflammation joined with debility, and the latter of debility alone. Hence there is greater heat and more florid colour of the skin in the former, with petechiæ, or purple spots, and aphthæ, or sloughs in the throat, and generally with previous contagion. When animal matter dies, as a slough in the throat, or the mortified part of a carbuncle, if it be kept moist and warm, as during its abhesion to a living body, it will soon putrify. This, and the origin of contagion from putrid animal substances, seem to have given rise to the septic and antiseptic theory of these fevers. The matter in pustules and ulcers is thus liable to become putrid, and to produce microscopic animalcula; the urine, if too long retained, may also gain a putrescent smell, as well as the alvine feces; but some writers have gone so far as to believe, that the blood itself in these fevers has smelt putrid, when drawn from the arm of the patient: but this seems not well founded; since a single particle of putrid matter taken into the blood can produce fever, how can we conceive that the whole mass could continue a minute in a putrid state without destroying life? Add to this, that putrid animal substances give up air, as in gangrenes; and that hence if the blood was putrid, air should be given out, which in the blood-vessels is known to occasion immediate death. In these sensitive fevers with strong pulse (or inflammations) there are two sensorial faculties concerned in producing the disease, viz. irritation and sensation; and hence, as their combined action is more violent, the general quantity of sensorial power becomes further exhausted during the exacerbation, and the system more rapidly weakened than in irritative fever with strong pulse; where the spirit of animation is weakened by but one mode of its exertion: so that this febris sensitiva pulsu forti (or inflammatory fever,) may be considered as the febris irritativa pulsu forti, with the addition of inflammation; and the febris sensitiva pulsu debili (or malignant fever) may be considered as the febris irritativa pulsu debili (or nervous fever), with the addition of inflammation. 4. In these putrid or malignant fevers a deficiency of irritability accompanies the increase of sensibility; and by this waste of sensorial power by the excess of sensation, which was already too small, arises the delirium and stupor which so perpetually attend these inflammatory fevers with arterial debility. In these cases the voluntary power first ceases to act from deficiency of sensorial spirit; and the stimuli from external bodies have no effect on the exhausted sensorial power, and a delirium like a dream is the consequence. At length the internal stimuli cease to excite sufficient irritation, and the secretions are either not produced at all, or too parsimonious in quantity. Amongst these the secretion of the brain, or production of the sensorial power, becomes deficient, till at last all sensorial power ceases, except what is just necessary to perform the vital motions, and a stupor succeeds; which is thus owing to the same cause as the preceding delirium exerted in a greater degree. This kind of delirium is owing to a suspension of volition, and to the disobedience of the senses to external stimuli, and is always occasioned by great debility, or paucity of sensorial power; it is therefore a bad sign at the end of inflammatory fevers, which had previous arterial strength, as rheumatism, or pleurisy, as it shews the presence of great exhaustion of sensorial power in a system, which having lately been exposed to great excitement, is not so liable to be stimulated into its healthy action, either by additional stimulus of food and medicines, or by the accumulation of sensorial power during its present torpor. In inflammatory fevers with debility, as those termed putrid fevers, delirium is sometimes, as well as stupor, rather a favourable sign; as less sensorial power is wasted during its continuance (see Class II. 1. 6. 8.), and the constitution not having been previously exposed to excess of stimulation, is more liable to be excited after previous quiescence. When the sum of general pleasurable sensation becomes too great, another kind of delirium supervenes, and the ideas thus excited are mistaken for the irritations of external objects: such a delirium is produced for a time by intoxicating drugs, as fermented liquors, or opium: a permanent delirium of this kind is sometimes induced by the pleasures of inordinate vanity, or by the enthusiastic hopes of heaven. In these cases the power of volition is incapable of exertion, and in a great degree the external senses become incapable of perceiving their adapted stimuli, because the whole sensorial power is employed or expended on the ideas excited by pleasurable sensation. This kind of delirium is distinguished from that which attends the fevers above mentioned from its not being accompanied with general debility, but simply with excess of pleasurable sensation; and is therefore in some measure allied to madness or to reverie; it differs from the delirium of dreams, as in this the power of volition is not totally suspended, nor are the senses precluded from external stimulation; there is therefore a degree of consistency, in this kind of delirium, and a degree of attention to external objects, neither of which exist in the delirium of fevers or in dreams. 5. It would appear, that the vascular system of other animals are less liable to be put into action by their general sum of pleasurable or painful sensation; and that the trains of their ideas, and the muscular motions usually associated with them, are less powerfully connected than in the human system. For other animals neither weep, nor smile, nor laugh; and are hence seldom subject to delirium, as treated of in Sect. XVI. on Instinct. Now as our epidemic and contagious diseases are probably produced by disagreeable sensation, and not simply by irritation; there appears a reason, why brute animals are less liable to epidemic or contagious diseases; and secondly, why none of our contagions, as the small-pox or measles, can be communicated to them, though one of theirs, viz. the hydrophobia, as well as many of their poisons, as those of snakes and of in insects, communicate their deleterious or painful effects to mankind. Where the quantity of general painful sensation is too great in the system, inordinate voluntary exertions are produced either of our ideas, as in melancholy and madness, or of our muscles, as in convulsion. From these maladies also brute animals are much more exempt than mankind, owing to their greater inaptitude to voluntary exertion, as mentioned in Sect. XVI. on Instinct. II. 1. When any moving organ is excited into such violent motions, that a quantity of pleasurable or painful sensation is produced, it frequently happens (but not always) that new motions of the affected organ are generated in consequence of the pain or pleasure, which are termed inflammation. These new motions are of a peculiar kind, tending to distend the old, and to produce new fibres, and thence to elongate the straight muscles, which serve locomotion, and to form new vessels at the extremities or sides of the vascular muscles. 2. Thus the pleasurable sensations produce an enlargement of the nipples of nurses, of the papillæ of the tongue, of the penis, and probably produce the growth of the body from its embryon state to its maturity; whilst the new motions in consequence of painful sensation, with the growth of the fibres or vessels, which they occasion, are termed inflammation. Hence when the straight muscles are inflamed, part of their tendons at each extremity gain new life and sensibility, and thus the muscle is for a time elongated; and inflamed bones become soft, vascular, and sensible. Thus new vessels shoot over the cornea of inflamed eyes, and into scirrhous tumours, when they become inflamed; and hence all inflamed parts grow together by intermixture, and inosculation of the new and old vessels. The heat is occasioned from the increased secretions either of mucus, or of the fibres, which produce or elongate the vessels. The red colour is owing to the pellucidity of the newly formed vessels, and as the arterial parts of them are probably formed before their correspondent venous parts. 3. These new motions are excited either from the increased quantity of sensation in consequence of greater fibrous contractions, or from increased sensibility, that is, from the increased quantity of sensorial power in the moving organ. Hence they are induced by great external stimuli, as by wounds, broken bones; and by acrid or infectious materials; or by common stimuli on those organs, which have been some time quiescent; as the usual light of the day inflames the eyes of those, who have been confined in dungeons; and the warmth of a common fire inflames those, who have been previously exposed to much cold. But these new motions are never generated by that pain, which arises from defect of stimulus, as from hunger, thirst, cold, or inanition, with all those pains, which are termed nervous. Where these pains exist, the motions of the affected part are lessened; and if inflammation succeeds, it is in some distant parts; as coughs are caused by coldness and moisture being long applied to the feet; or it is in consequence of the renewal of the stimulus, as of heat or food, which excites our organs into stronger action after their temporary quiescence; as kibed heels after walking in snow. 4. But when these new motions of the vascular muscles are exerted with greater violence, and these vessels are either elongated too much or too hastily, a new material is secreted from their extremities, which is of various kinds according to the peculiar animal motions of this new kind of gland, which secretes it; such is the pus laudabile or common matter, the variolous matter, venereal matter, catarrhous matter, and many others. 5. These matters are the product of an animal process; they are secreted or produced from the blood by certain diseased motions of the extremities of the blood-vessels, and are on that account all of them contagious; for if a portion of any of these matters is transmitted into the circulation, or perhaps only inserted into the skin, or beneath the cuticle of an healthy person, its stimulus in a certain time produces the same kind of morbid motions, by which itself was produced; and hence a similar kind is generated. See Sect. XXXIX. 6. 1. 6. It is remarkable, that many of these contagious matters are capable of producing a similar disease but once; as the small-pox and measles; and I suppose this is true of all those contagious diseases, which are spontaneously cured by nature in a certain time; for if the body was capable of receiving the disease a second time, the patient must perpetually infect himself by the very matter, which he has himself produced, and is lodged about him; and hence he could never become free from the disease. Something similar to this is seen in the secondary fever of the confluent small-pox; there is a great absorption of variolous matter, a very minute part of which would give the genuine small-pox to another person; but here it only stimulates the system into common fever; like that which common puss, or any other acrid material might occasion. 7. In the pulmonary consumption, where common matter is daily absorbed, an irritative fever only, without new inflammation, is generally produced; which is terminated like other irritative fevers by sweats, or loose stools. Hence it does not appear, that this absorbed matter always acts as a contagious material producing fresh inflammation or new abscesses. Though there is reason to believe, that the first time any common matter is absorbed, it has this effect, but not the second time, like the variolous matter above mentioned. This accounts for the opinion, that the pulmonary consumption is sometimes infectious, which opinion was held by the ancients, and continues in Italy at present; and I have myself seen three or four instances, where a husband and wife, who have slept together, and have thus much received each other's breath, who have infected each other, and both died in consequence of the original taint of only one of them. This also accounts for the abscesses in various parts of the body, that are sometimes produced after the inoculated small-pox is terminated; for this second absorption of variolous matter acts like common matter, and produces only irritative fever in those children, whose constitutions have already experienced the absorption of common matter; and inflammation with a tendency to produce new abscesses in those, whose constitutions have not experienced the absorptions of common matter. It is probable, that more certain proofs might have been found to shew, that common matter is infectious the first time it is absorbed, tending to produce similar abscesses, but not the second time of its absorption, if this subject had been attended to. 8. These contagious diseases are very numerous, as the plague, small-pox, chicken-pox, measles, scarlet-fever, pemphigus, catarrh, chincough, venereal disease, itch, trichoma, tinea. The infectious material does not seem to be dissolved by the air, but only mixed with it perhaps in fine powder, which soon subsides; since many of these contagions can only be received by actual contact; and others of them only at small distances from the infected person; as is evident from many persons having been near patients of the small-pox without acquiring the disease. The reason, why many of these diseases are received but once, and others repeatedly, is not well understood; it appears to me, that the constitution becomes so accustomed to the stimuli of these infectious materials, by having once experienced them, that though irritative motions, as hectic fevers, may again be produced by them, yet no sensation, and in consequence no general inflammation succeeds; as disagreeable smells or tastes by habit cease to be perceived; they continue indeed to excite irritative ideas on the organs of sense, but these are not succeeded by sensation. There are many irritative motions, which were at first succeeded by sensation, but which by frequent repetition cease to excite sensation, as explained in Sect. XX. on Vertigo. And, that this circumstance exists in respect to infectious matter appears from a known fact; that nurses, who have had the small-pox, are liable to experience small ulcers on their arms by the contact of variolous matter in lifting their patients; and that when patients, who have formerly had the small-pox have been inoculated in the arm, a phlegmon, or inflamed sore, has succeeded, but no subsequent fever. Which shews, that the contagious matter of the small-pox has not lost its power of stimulating the part it is applied to, but that the general system is not affected in consequence. See Section XII. 7. 6. XIX. 9. 9. From the accounts of the plague, virulent catarrh, and putrid dysentery, it seems uncertain, whether these diseases are experienced more than once; but the venereal disease and itch are doubtless repeatedly infectious; and as these diseases are never cured spontaneously, but require medicines, which act without apparent operation, some have suspected, that the contagious material produces similar matter rather by a chemical change of the fluids, than by an animal process; and that the specific medicines destroy their virus by chemically combining with it. This opinion is successfully combated by Mr. Hunter, in his Treatise on Venereal Disease, Part I. c. i. But this opinion wants the support of analogy, as there is no known process in animal bodies, which is purely chemical, not even digestion; nor can any of these matters be produced by chemical processes. Add to this, that it is probable, that the insects, observed in the pustules of the itch, and in the stools of dysenteric patients, are the consequences, and not the causes of these diseases. And that the specific medicines, which cure the itch and lues venerea, as brimstone and mercury, act only by increasing the absorption of the matter in the ulcuscles of those diseases, and thence disposing them to heal; which would otherwise continue to spread. Why the venereal disease, and itch, and tenia, or scald head, are repeatedly contagious, while those contagions attended with fever can be received but once, seems to depend on their being rather local diseases than universal ones, and are hence not attended with fever, except the purulent fever in their last stages, when the patient is destroyed by them. On this account the whole of the system does not become habituated to these morbid actions, so as to cease to be affected with sensation by a repetition of the contagion. Thus the contagious matter of the venereal disease, and of the tenia, affects the lymphatic glands, as the inquinal glands, and those about the roots of the hair and neck, where it is arrested, but does not seem to affect the blood-vessels, since no fever ensues. Hence it would appear, that these kinds of contagion are propagated not by means of the circulation, but by sympathy of distant parts with each other; since if a distant part, as the palate, should be excited by sensitive association into the same kind of motions, as the parts originally affected by the contact of infectious matter; that distant part will produce the same kind of infectious matter; for every secretion from the blood is formed from it by the peculiar motions of the fine extremities of the gland, which secretes it; the various secreted fluids, as the bile, saliva, gastric juice, not previously existing, as such, in the blood-vessels. And this peculiar sympathy between the genitals and the throat, owing to sensitive association, appears not only in the production of venereal ulcers in the throat, but in variety of other instances, as in the mumps, in the hydrophobia, some coughs, strangulation, the production of the beard, change of voice at puberty. Which are further described in Class IV. 1. 2. 7. To evince that the production of such large quantities of contagious matter, as are seen in some variolous patients, so as to cover the whole skin almost with pustules, does not arise from any chemical fermentation in the blood, but that it is owing to morbid motions of the fine extremities of the capillaries, or glands, whether these be ruptured or not, appears from the quantity of this matter always corresponding with the quantity of the fever; that is, with the violent exertions of those glands and capillaries, which are the terminations of the arterial system. The truth of this theory is evinced further by a circumstance observed by Mr. J. Hunter, in his Treatise on Venereal Disease; that in a patient, who was inoculated for the small-pox, and who appeared afterwards to have been previously infested with the measles, the progress of the small-pox was delayed till the measles had run their course, and that then the small-pox went through its usual periods. Two similar cases fell under my care, which I shall here relate, as it confirms that of Mr. Hunter, and contributes to illustrate this part of the theory of contagious diseases. I have transcribed the particulars from a letter of Mr. Lightwood of Yoxal, the surgeon who daily attended them, and at my request, after I had seen them, kept a kind of journal of their cases. Miss H. and Miss L. two sisters, the one about four and the other about three years old, were inoculated Feb. 7, 1791. On the 10th there was a redness on both arms discernible by a glass. On the 11th their arms were so much inflamed as to leave no doubt of the infection having taken place. On the 12th less appearance of inflammation on their arms. In the evening Miss L. had an eruption, which resembled the measles. On the 12th the eruption on Miss L. was very full on the face and breast, like the measles, with considerable fever. It was now known, that the measles were in a farm house in the neighbourhood. Miss H.'s arm less inflamed than yesterday. On the 14th Miss L.'s fever great, and the eruption universal. The arm appears to be healed. Miss H.'s arm somewhat redder. They were now put into separate rooms. On the 15th Miss L.'s arms as yesterday. Eruption continues. Miss H.'s arms have varied but little. 16th, the eruptions on Miss L. are dying away, her fever gone. Begins to have a little redness in one arm at the place of inoculation. Miss H.'s arms get redder, but she has no appearance of complaint. 20th, Miss L.'s arms have advanced slowly till this day, and now a few pustules appear. Miss H.'s arm has made little progress from the 16th to this day, and now she has some fever. 21st, Miss L. as yesterday. Miss H. has much inflammation, and an increase of the red circle on one arm to the size of half a crown, and had much fever at night, with fetid breath. 22d, Miss L.'s pustules continue advancing. Miss H.'s inflammation of her arm and red circle increases. A few red spots appear in different parts with some degree of fever this morning, 23d. Miss L. has a larger crop of pustules. Miss H. has small pustules and great inflammation of her arms, with but one pustule likely to suppurate. After this day they gradually got well, and the pustules disappeared. In one of these cases the measles went through their common course with milder symptoms than usual, and in the other the measly contagion seemed just sufficient to stop the progress of variolous contagion, but without itself throwing the constitution into any disorder. At the same time both the measles and small-pox seem to have been rendered milder. Does not this give an idea, that if they were both inoculated at the same time, that neither of them might affect the patient? From these cases I contend, that the contagious matter of these diseases does not affect the constitution by a fermentation, or chemical change of the blood, because then they must have proceeded together, and have produced a third something, not exactly similar to either of them: but that they produce new motions of the cutaneous terminations of the blood-vessels, which for a time proceed daily with increasing activity, like some paroxysms of fever, till they at length secrete or form a similar poison by these unnatural actions. Now as in the measles one kind of unnatural motion takes place, and in the small-pox another kind, it is easy to conceive, that these different kinds of morbid motions cannot exist together; and therefore, that that which has first begun will continue till the system becomes habituated to the stimulus which occasions it, and has ceased to be thrown into action by it; and then the other kind of stimulus will in its turn produce fever, and new kinds of motions peculiar to itself. 10. On further considering the action of contagious matter, since the former part of this work was sent to the press; where I have asserted, in Sect. XXII. 3. 3. that it is probable, that the variolous matter is diffused through the blood; I prevailed on my friend Mr. Power, surgeon at Bosworth in Leicestershire to try, whether the small-pox could be inoculated by using the blood of a variolous patient instead of the matter from the pustules; as I thought such an experiment might throw some light at least on this interesting subject. The following is an extract from his letter:-- "March 11, 1793. I inoculated two children, who had not had the small-pox, with blood; which was taken from a patient on the second day after the eruption commenced, and before it was completed. And at the same time I inoculated myself with blood from the same person, in order to compare the appearances, which might arise in a person liable to receive the infection, and in one not liable to receive it. On the same day I inoculated four other children liable to receive the infection with blood taken from another person on the fourth day after the commencement of the eruption. The patients from whom the blood was taken had the disease mildly, but had the most pustules of any I could select from twenty inoculated patients; and as much of the blood was insinuated under the cuticle as I could introduce by elevating the skin without drawing blood; and three or four such punctures were made in each of their arms, and the blood was used in its fluid state. "As the appearances in all these patients, as well as in myself, were similar, I shall only mention them in general terms. March 13. A slight subcuticular discoloration, with rather a livid appearance, without soreness or pain, was visible in them all, as well as in my own hand. 15. The discoloration somewhat less, without pain or soreness. Some patients inoculated on the same day with variolous matter have considerable inflammation. 17. The discoloration is quite gone in them all, and from my own hand, a dry mark only remaining. And they were all inoculated on the 18th, with variolous matter, which produced the disease in them all." Mr. Power afterwards observes, that, as the patients from whom the blood was taken had the disease mildly, it may be supposed, that though the contagious matter might be mixed with the blood, it might still be in too dilute a state to convey the infection; but adds at the same time, that he has diluted recent matter with at least five times its quantity of water, and which has still given the infection; though he has sometimes diluted it so far as to fail. The following experiments were instituted at my request by my friend Mr. Hadley, surgeon in Derby, to ascertain whether the blood of a person in the small-pox be capable of communicating the disease. "Experiment 1st. October 18th, 1793. I took some blood from a vein in the arm of a person who had the small-pox, on the second day of the eruption, and introduced a small quantity of it immediately with the point of a lancet between the scars and true skin of the right arm of a boy nine years old in two or three different places; the other arm was inoculated with variolous matter at the same time. "19th. The punctured parts of the right arm were surrounded with some degree of subcuticular inflammation. 20th. The inflammation more considerable, with a slight degree of itching, but no pain upon pressure. 21st. Upon examining the arm this day with a lens I found the inflammation less extensive, and the redness changing to a deep yellow or orange-colour, 22d. Inflammation nearly gone. 23d. Nothing remained, except a slight discoloration and a little scurfy appearance on the punctures. At the same time the inflammation of the arm inoculated with variolous matter was increasing fast, and he had the disease mildly at the usual time. "Experiment 2d. I inoculated another child at the same time and in the same manner, with blood taken on the first day of the eruption; but as the appearance and effects were similar to those in the preceding experiment, I shall not relate them minutely. "Experiment 3d. October 20th. Blood was taken from a person who had the small-pox, on the third day of the eruption, and on the sixth from the commencement of the eruptive fever. I introduced some of it in its fluid state into both arms of a boy seven years old. 21st. There appeared to be some inflammation under the cuticle, where the punctures were made. 22d. Inflammation more considerable. 23d. On this day the inflammation was somewhat greater, and the cuticle rather elevated. "24th. Inflammation much less, and only a brown or orange-colour remained. 25th. Scarcely any discoloration left. On this day he was inoculated with variolous matter, the progress of the infection went on in the usual way, and he had the small-pox very favourably. "At this time I was requested to inoculate a young person, who was thought to have had the small-pox, but his parents were not quite certain; in one arm I introduced variolous matter, and in the other blood, taken as in experiment 3d. On the second day after the operation, the punctured parts were inflamed, though I think the arm in which I had inserted variolous matter was rather more so than the other. On the third the inflammation was increased, and looked much the same as in the preceding experiment. 4th. The inflammation was much diminished, and on the 5th almost gone. He was exposed at the same time to the natural infection, but has continued perfectly well. "I have frequently observed (and believe most practitioners have done the same), that if variolous matter be inserted in the arm of a person who has previously had the small-pox, that the inflammation on the second or third days is much greater, than if they had not had the disease, but on the fourth or fifth it disappears. "On the 23d I introduced blood into the arms of three more children, taken on the third and fourth days of the eruption. The appearances were much the same as mentioned in experiments first and third. They were afterwards inoculated with variolous matter, and had the disease in the regular way. "The above experiments were made with blood taken from a small vein in the hand or foot of three or four different patients, whom I had at that time under inoculation. They were selected from 160, as having the greatest number of pustules. The part was washed with warm water before the blood was taken, to prevent the possibility of any matter being mixed with it from the surface." Shall we conclude from hence, that the variolous matter never enters the blood-vessels? but that the morbid motions of the vessels of the skin around the insertion of it continue to increase in a larger and larger circle for six or seven days; that then their quantity of morbid action becomes great enough to produce a fever-fit, and to affect the stomach by association of motions? and finally, that a second association of motions is produced between the stomach and the other parts of the skin, inducing them into morbid actions similar to those of the circle round the insertion of the variolous matter? Many more experiments and observations are required before this important question can be satisfactorily answered. It may be adduced, that as the matter inserted into the skin of the arm frequently swells the lymphatic in the axilla, that in that circumstance it seems to be there arrested in its progress, and cannot be imagined to enter the blood by that lymphatic gland till the swelling of it subsides. Some other phænomena of the disease are more easily reconcileable to this theory of sympathetic motions than to that of absorption; as the time taken up between the insertion of the matter, and the operation of it on the system, as mentioned above. For the circle around the insertion is seen to increase, and to inflame; and I believe, undergoes a kind of diurnal paroxysm of torpor and paleness with a succeeding increase of action and colour, like a topical fever-fit. Whereas if the matter is conceived to circulate for six or seven days with the blood, without producing disorder, it ought to be rendered milder, or the blood-vessels more familiarized to its acrimony. It is much easier to conceive from this doctrine of associated or sympathetic motions of distant parts of the system, how it happens, that the variolous infection can be received but once, as before explained; than by supposing, that a change is effected in the mass of blood by any kind of fermentative process. The curious circumstance of the two contagions of small-pox and measles not acting at the same time, but one of them resting or suspending its action till that of the other ceases, may be much easier explained from sympathetic or associated actions of the infected part with other parts of the system, than it can from supposing the two contagions to enter the circulation. The skin of the face is subject to more frequent vicissitudes of heat and cold, from its exposure to the open air, and is in consequence more liable to sensitive association with the stomach than any other part of the surface of the body, because their actions have been more frequently thus associated. Thus in a surfeit from drinking cold water, when a person is very hot and fatigued, an eruption is liable to appear on the face in consequence of this sympathy. In the same manner the rosy eruption on the faces of drunkards more probably arises from the sympathy of the face with the stomach, rather than between the face and the liver, as is generally supposed. This sympathy between the stomach and the skin of the face is apparent in the eruption of the small-pox; since, where the disease is in considerable quantity, the eruption on the face first succeeds the sickness of the stomach. In the natural disease the stomach seems to be frequently primarily affected, either alone or along with the tonsils, as the matter seems to be only diffused in the air, and by being mixed with the saliva, or mucus of the tonsils, to be swallowed into the stomach. After some days the irritative circles of motions become disordered by this new stimulus, which acts upon the mucus lining of the stomach; and sickness, vertigo, and a diurnal fever succeed. These disordered irritative motions become daily increased for two or three days, and then by their increased action certain sensitive motions, or inflammation, is produced, and at the next cold fit of fever, when the stomach recovers from its torpor, an inflammation of the external skin is formed in points (which afterwards suppurate), by sensitive association, in the same manner as a cough is produced in consequence of exposing the feet to cold, as described in Sect. XXV. 17. and Class IV. 2. I. 7. If the inoculated skin of the arm, as far as it appears inflamed, was to be cut out, or destroyed by caustic, before the fever commenced, as suppose on the fourth day after inoculation, would this prevent the disease? as it is supposed to prevent the hydrophobia. III. 1. Where the new vessels, and enlarged old ones, which constitute inflammation, are not so hastily distended as to burst, and form a new kind of gland for the secretion of matter, as above mentioned; if such circumstances happen as diminish the painful sensation, the tendency to growth ceases, and by and by an absorption commences, not only of the superabundant quantity of fluids deposited in the inflamed part, but of the solids likewise, and this even of the hardest kind. Thus during the growth of the second set of teeth in children, the roots of the first set are totally absorbed, till at length nothing of them remains but the crown; though a few weeks before, if they are drawn immaturely, their roots are found complete. Similar to this Mr. Hunter has observed, that where a dead piece of bone is to exfoliate, or to separate from a living one, that the dead part does not putrify, but remains perfectly sound, while the surface of the living part of the bone, which is in contact with the dead part, becomes absorbed, and thus effects its separation. Med. Comment. Edinb. V. 1. 425. In the same manner the calcareous matter of gouty concretions, the coagulable lymph deposited on inflamed membranes in rheumatism and extravasated blood become absorbed; which are all as solid and as indissoluble materials as the new vessels produced in inflammation. This absorption of the new vessels and deposited fluids of inflamed parts is called resolution: it is produced by first using such internal means as decrease the pain of the part, and in consequence its new motions, as repeated bleeding, cathartics, diluent potations, and warm bath. After the vessels are thus emptied, and the absorption of the new vessels and deposited fluids is evidently begun, it is much promoted by stimulating the part externally by solutions of lead, or other metals, and internally by the bark, and small doses of opium. Hence when an ophthalmy begins to become paler, any acrid eye-water, as a solution of six grains of white vitriol in an ounce of water, hastens the absorption, and clears the eye in a very short time. But the same application used a few days sooner would have increased the inflammation. Hence after evacuation opium in small doses may contribute to promote the absorption of fluids deposited on the brain, as observed by Mr. Bromfield in his treatise of surgery. 2. Where an abscess is formed by the rupture of these new vessels, the violence of inflammation ceases, and a new gland separates a material called pus: at the same time a less degree of inflammation produces new vessels called vulgarly proud flesh; which, if no bandage confines its growth, nor any other circumstance promotes absorption in the wound, would rise to a great height above the usual size of the part. Hence the art of healing ulcers consists in producing a tendency to absorption in the wound greater than the deposition. Thus when an ill-conditioned ulcer separates a copious and thin discharge, by the use of any stimulus, as of salts of lead, or mercury, or copper externally applied, the discharge becomes diminished in quantity, and becomes thicker, as the thinner parts are first absorbed. But nothing so much contributes to increase the absorption in a wound as covering the whole limb above the sore with a bandage, which should be spread with some plaster, as with emplastrum de minio, to prevent it from slipping. By this artificial tightness of the skin, the arterial pulsations act with double their usual power in promoting the ascending current of the fluid in the valvular lymphatics. Internally the absorption from ulcers should be promoted first by evacuation, then by opium, bark, mercury, steel. 3. Where the inflammation proceeds with greater violence or rapidity, that is, when by the painful sensation a more inordinate activity of the organ is produced, and by this great activity an additional quantity of painful sensation follows in an increasing ratio, till the whole of the sensorial power, or spirit of animation, in the part becomes exhausted, a mortification ensues, as in a carbuncle, in inflammations of the bowels, in the extremities of old people, or in the limbs of those who are brought near a fire after having been much benumbed with cold. And from hence it appears, why weak people are more subject to mortification than strong ones, and why in weak persons less pain will produce mortification, namely, because the sensorial power is sooner exhausted by any excess of activity. I remember seeing a gentleman who had the preceding day travelled two stages in a chaise with what he termed a bearable pain in his bowels; which when I saw him had ceased rather suddenly, and without a passage through him; his pulse was then weak, though not very quick; but as nothing which he swallowed would continue in his stomach many minutes, I concluded that the bowel was mortified; he died on the next day. It is usual for patients sinking under the small-pox with mortified pustules, and with purple spots intermixed, to complain of no pain, but to say they are pretty well to the last moment. _Recapitulation._ IV. When the motions of any part of the system, in consequence of previous torpor, are performed with more energy than in the irritative fevers, a disagreeable sensation is produced, and new actions of some part of the system commence in consequence of this sensation conjointly with the irritation: which motions constitute inflammation. If the fever be attended with a strong pulse, as in pleurisy, or rheumatism, it is termed synocha sensitiva, or sensitive fever with strong pulse; which is usually termed inflammatory fever. If it be attended with weak pulse, it is termed typhus sensitivus, or sensitive fever with weak pulse, or typhus gravior, or putrid malignant fever. The synocha sensitiva, or sensitive fever with strong pulse, is generally attended with some topical inflammation, as in peripneumony, hepatitis, and is accompanied with much coagulable lymph, or size; which rises to the surface of the blood, when taken into a bason, as it cools; and which is believed to be the increased mucous secretion from the coats of the arteries, inspissated by a greater absorption of its aqueous and saline part, and perhaps changed by its delay in the circulation. The typhus sensitivus, or sensitive fever with weak pulse, is frequently attended with delirium, which is caused by the deficiency of the quantity of sensorial power, and with variety of cutaneous eruptions. Inflammation is caused by the pains occasioned by excess of action, and not by those pains which are occasioned by defect of action. These morbid actions, which are thus produced by two sensorial powers, viz. by irritation and sensation, secrete new living fibres, which elongate the old vessels, or form new ones, and at the same time much heat is evolved from these combinations. By the rupture of these vessels, or by a new construction of their apertures, purulent matters are secreted of various kinds; which are infectious the first time they are applied to the skin beneath the cuticle, or swallowed with the saliva into the stomach. This contagion acts not by its being absorbed into the circulation, but by the sympathies, or associated actions, between the part first stimulated by the contagious matter and the other parts of the system. Thus in the natural small-pox the contagion is swallowed with the saliva, and by its stimulus inflames the stomach; this variolous inflammation of the stomach increases every day, like the circle round the puncture of an inoculated arm, till it becomes great enough to disorder the circles of irritative and sensitive motions, and thus produces fever-fits, with sickness and vomiting. Lastly, after the cold paroxysm, or fit of torpor, of the stomach has increased for two or three successive days, an inflammation of the skin commences in points; which generally first appear upon the face, as the associated actions between the skin of the face and that of the stomach have been more frequently exerted together than those of any other parts of the external surface. Contagious matters, as those of the measles and small-pox, do not act upon the system at the same time; but the progress of that which was last received is delayed, till the action of the former infection ceases. All kinds of matter, even that from common ulcers, are probably contagious the first time they are inserted beneath the cuticle or swallowed into the stomach; that is, as they were formed by certain morbid actions of the extremities of the vessels, they have the power to excite similar morbid actions in the extremities of other vessels, to which they are applied; and these by sympathy, or associations of motion, excite similar morbid actions in distant parts of the system, without entering the circulation; and hence the blood of a patient in the small-pox will not give that disease by inoculation to others. When the new fibres or vessels become again absorbed into the circulation, the inflammation ceases; which is promoted, after sufficient evacuations, by external stimulants and bandages: but where the action of the vessels is very great, a mortification of the part is liable to ensue, owing to the exhaustion of sensorial power; which however occurs in weak people without much pain, and without very violent previous inflammation; and, like partial paralysis, may be esteemed one mode of natural death of old people, a part dying before the whole. * * * * * SECT. XXXIV. DISEASES OF VOLITION. I. 1. _Volition defined. Motions termed involuntary are caused by volition. Desires opposed to each other. Deliberation. Ass between two hay-cocks. Saliva swallowed against one's desire. Voluntary motions distinguished from those associated with sensitive motions._ 2. _Pains from excess, and from defect of motion. No pain is felt during vehement voluntary exertion; as in cold fits of ague, labour-pains, strangury, tenesmus, vomiting, restlessness in fevers, convulsion of a wounded muscle._ 3. _Of holding the breath and screaming in pain; why swine and dogs cry out in pain, and not sheep and horses. Of grinning and biting in pain; why mad animals bite others._ 4. _Epileptic convulsions explained, why the fits begin with quivering of the under jaw, biting the tongue, and setting the teeth; why the convulsive motions are alternately relaxed. The phenomenon of laughter explained. Why children cannot tickle themselves. How some have died from immoderate laughter._ 5. _Of cataleptic spasms, of the locked jaw, of painful cramps._ 6. _Syncope explained. Why no external objects are perceived in syncope._ 7. _Of palsy and apoplexy from violent exertions. Case of Mrs. Scot. From dancing, scating, swimming. Case of Mr. Nairn. Why palsies are not always immediately preceded by violent exertions. Palsy and epilepsy from diseased livers. Why the right arm more frequently paralytic than the left. How paralytic limbs regain their motions._ II. _Diseases of the sensual motions from excess or defect of voluntary exertion._ 1. _Madness._ 2. _Distinguished from delirium._ 3. _Why mankind more liable to insanity than brutes._ 4. _Suspicion. Want of shame, and of cleanliness._ 5. _They bear cold, hunger, and fatigue. Charles XII. of Sweden._ 6. _Pleasureable delirium, and insanity. Child riding on a stick. Pains of martyrdom not felt._ 7. _Dropsy._ 8. _Inflammation cured by insanity._ III. 1. _Pain relieved by reverie. Reverie is an exertion of voluntary and sensitive motions._ 2. _Case of reverie._ 3. _Lady supposed to have two souls._ 4. _Methods of relieving pain._ I. 1. Before we commence this Section on Diseased Voluntary Motions, it may be necessary to premise, that the word volition is not used in this work exactly in its common acceptation. Volition is said in Section V. to bear the same analogy to desire and aversion, which sensation does to pleasure and pain. And hence that, when desire or aversion produces any action of the muscular fibres, or of the organs of sense, they are termed volition; and the actions produced in consequence are termed voluntary actions. Whence it appears, that motions of our muscles or ideas may be produced in consequence of desire or aversion without our having the power to prevent them, and yet these motions may be termed voluntary, according to our definition of the word; though in common language they would be called involuntary. The objects of desire and aversion are generally at a distance, whereas those of pleasure and pain are immediately acting upon our organs. Hence, before desire or aversion are exerted, so as to cause any actions, there is generally time for deliberation; which consists in discovering the means to obtain the object of desire, or to avoid the object of aversion; or in examining the good or bad consequences, which may result from them. In this case it is evident, that we have a power to delay the proposed action, or to perform it; and this power of choosing, whether we shall act or not, is in common language expressed by the word volition, or will. Whereas in this work the word volition means simply the active state of the sensorial faculty in producing motion in consequence of desire or aversion: whether we have the power of restraining that action, or not; that is, whether we exert any actions in consequence of opposite desires or aversions, or not. For if the objects of desire or aversion are present, there is no necessity to investigate or compare the _means_ of obtaining them, nor do we always deliberate about their consequences; that is, no deliberation necessarily intervenes, and in consequence the power of choosing to act or not is not exerted. It is probable, that this twofold use of the word volition in all languages has confounded the metaphysicians, who have disputed about free will and necessity. Whereas from the above analysis it would appear, that during our sleep, we use no voluntary exertions at all; and in our waking hours, that they are the consequence of desire or aversion. To will is to act in consequence of desire; but to desire means to desire something, even if that something be only to become free from the pain, which causes the desire; for to desire nothing is not to desire; the word desire, therefore, includes both the action and the object or motive; for the object and motive of desire are the same thing. Hence to desire without an object, that is, without a motive, is a solecism in language. As if one should ask, if you could eat without food, or breathe without air. From this account of volition it appears, that convulsions of the muscles, as in epileptic fits, may in the common sense of that word be termed involuntary; because no deliberation is interposed between the desire or aversion and the consequent action; but in the sense of the word, as above defined, they belong to the class of voluntary motions, as delivered in Vol. II. Class III. If this use of the word be discordant to the ear of the reader, the term morbid voluntary motions, or motions in consequence of aversion, may be substituted in its stead. If a person has a desire to be cured of the ague, and has at the same time an aversion (or contrary desire) to swallowing an ounce of Peruvian bark; he balances desire against desire, or aversion against aversion; and thus he acquires the power of choosing, which is the common acceptation of the word _willing_. But in the cold fit of ague, after having discovered that the act of shuddering, or exerting the subcutaneous muscles, relieves the pain of cold; he immediately exerts this act of volition, and shudders, as soon as the pain and consequent aversion return, without any deliberation intervening; yet is this act, as well as that of swallowing an ounce of the bark, caused by volition; and that even though he endeavours in vain to prevent it by a weaker contrary volition. This recalls to our minds the story of the hungry ass between two hay-stacks, where the two desires are supposed so exactly to counteract each other, that he goes to neither of the stacks, but perishes by want. Now as two equal and opposite desires are thus supposed to balance each other, and prevent all action, it follows, that if one of these hay-stacks was suddenly removed, that the ass would irresistibly be hurried to the other, which in the common use of the word might be called an involuntary act; but which, in our acceptation of it, would be classed amongst voluntary actions, as above explained. Hence to deliberate is to compare opposing desires or aversions, and that which is the most interesting at length prevails, and produces action. Similar to this, where two pains oppose each other, the stronger or more interesting one produces action; as in pleurisy the pain from suffocation would produce expansion of the lungs, but the pain occasioned by extending the inflamed membrane, which lines the chest, opposes this expansion, and one or the other alternately prevails. When any one moves his hand quickly near another person's eyes, the eye-lids instantly close; this act in common language is termed involuntary, as we have not time to deliberate or to exert any contrary desire or aversion, but in this work it would be termed a voluntary act, because it is caused by the faculty of volition, and after a few trials the nictitation can be prevented by a contrary or opposing volition. The power of opposing volitions is best exemplified in the story of Mutius Scævola, who is said to have thrust his hand into the fire before Porcenna, and to have suffered it to be consumed for having failed him in his attempt on the life of that general. Here the aversion for the loss of same, or the unsatisfied desire to serve his country, the two prevalent enthusiasms at that time, were more powerful than the desire of withdrawing his hand, which must be occasioned by the pain of combustion; of these opposing volitions Vincit amor patriæ, laudumque immensa cupido. If any one is told not to swallow his saliva for a minute, he soon swallows it contrary to his will, in the common sense of that word; but this also is a voluntary action, as it is performed by the faculty of volition, and is thus to be understood. When the power of volition is exerted on any of our senses, they become more acute, as in our attempts to hear small noises in the night. As explained in Section XIX. 6. Hence by our attention to the fauces from our desire not to swallow our saliva; the fauces become more sensible; and the stimulus of the saliva is followed by greater sensation, and consequent desire of swallowing it. So that the desire or volition in consequence of the increased sensation of the saliva is more powerful, than the previous desire not to swallow it. See Vol. II. Deglutitio invita. In the same manner if a modest man wishes not to want to make water, when he is confined with ladies in a coach or an assembly-room; that very act of volition induces the circumstance, which he wishes to avoid, as above explained; insomuch that I once saw a partial insanity, which might be called a voluntary diabetes, which was occasioned by the fear (and consequent aversion) of not being able to make water at all. It is further necessary to observe here, to prevent any confusion of voluntary, with sensitive, or associate motions, that in all the instances of violent efforts to relieve pain, those efforts are at first voluntary exertions; but after they have been frequently repeated for the purpose of relieving certain pains, they become associated with those pains, and cease at those times to be subservient to the will; as in coughing, sneezing, and strangury. Of these motions those which contribute to remove or dislodge the offending cause, as the actions of the abdominal muscles in parturition or in vomiting, though they were originally excited by volition, are in this work termed sensitive motions; but those actions of the muscles or organs of sense, which do not contribute to remove the offending cause, as in general convulsions or in madness, are in this work termed voluntary motions, or motions in consequence of aversion, though in common language they are called involuntary ones. Those sensitive unrestrainable actions, which contribute to remove the cause of pain are uniformly and invariably exerted, as in coughing or sneezing; but those motions which are exerted in consequence of aversion without contributing to remove the painful cause, but only to prevent the sensation of it, as in epileptic, or cataleptic fits, are not uniformly and invariably exerted, but change from one set of muscles to another, as will be further explained; and may by this criterion also be distinguished from the former. At the same time those motions, which are excited by perpetual stimulus, or by association with each other, or immediately by pleasureable or painful sensation, may properly be termed involuntary motions, as those of the heart and arteries; as the faculty of volition seldom affects those, except when it exists in unnatural quantity, as in maniacal people. 2. It was observed in Section XIV. on the Production of Ideas, that those parts of the system, which are usually termed the organs of sense, are liable to be excited into pain by the excess of the stimulus of those objects, which are by nature adapted to affect them; as of too great light, sound, or pressure. But that these organs receive no pain from the defect or absence of these stimuli, as in darkness or silence. But that our other organs of perception, which have generally been called appetites, as of hunger, thirst, want of heat, want of fresh air, are liable to be affected with pain by the defect, as well as by the excess of their appropriated stimuli. This excess or defect of stimulus is however to be considered only as the remote cause of the pain, the immediate cause being the excess or defect of the natural action of the affected part, according to Sect. IV. 5. Hence all the pains of the body may be divided into those from excess of motion, and those from defect of motion; which distinction is of great importance in the knowledge and the cure of many diseases. For as the pains from excess of motion either gradually subside, or are in general succeeded by inflammation; so those from defect of motion either gradually subside, or are in general succeeded by convulsion, or madness. These pains are easily distinguishable from each other by this circumstance, that the former are attended with heat of the pained part, or of the whole body; whereas the latter exists without increase of heat in the pained part, and is generally attended with coldness of the extremities of the body; which is the true criterion of what have been called nervous pains. Thus when any acrid material, as snuff or lime, falls into the eye, pain and inflammation and heat are produced from the excess of stimulus; but violent hunger, hemicrania, or the clavus hystericus, are attended with coldness of the extremities, and defect of circulation. When we are exposed to great cold, the pain we experience from the deficiency of heat is attended with a quiescence of the motions of the vascular system; so that no inflammation is produced, but a great desire of heat, and a tremulous motion of the subcutaneous muscles, which is properly a convulsion in consequence of this pain from defect of the stimulus of heat. It was before mentioned, that as sensation consists in certain movements of the sensorium, beginning at some of the extremities of it, and propagated to the central parts of it; so volition consists of certain other movements of the sensorium, commencing in the central parts of it, and propagated to some of its extremities. This idea of these two great powers of motion in the animal machine is confirmed from observing, that they never exist in a great degree or universally at the same time; for while we strongly exert our voluntary motions, we cease to feel the pains or uneasinesses, which occasioned us to exert them. Hence during the time of fighting with fists or swords no pain is felt by the combatants, till they cease to exert themselves. Thus in the beginning of ague-fits the painful sensation of cold is diminished, while the patient exerts himself in the shivering and gnashing of his teeth. He then ceases to exert himself, and the pain of cold returns; and he is thus perpetually induced to reiterate these exertions, from which he experiences a temporary relief. The same occurs in labour-pains, the exertion of the parturient woman relieves the violence of the pains for a time, which recur again soon after she has ceased to use those exertions. The same is true in many other painful diseases, as in the strangury, tenesmus, and the efforts of vomiting; all these disagreeable sensations are diminished or removed for a time by the various exertions they occasion, and recur alternately with those exertions. The restlessness in some fevers is an almost perpetual exertion of this kind, excited to relieve some disagreeable sensations; the reciprocal opposite exertions of a wounded worm, the alternate emprosthotonos and opisthotonos of some spasmodic diseases, and the intervals of all convulsions, from whatever cause, seem to be owing to this circumstance of the laws of animation; that great or universal exertion cannot exist at the same time with great or universal sensation, though they can exist reciprocally; which is probably resolvable into the more general law, that the whole sensorial power being expended in one mode of exertion, there is none to spare for any other. Whence syncope, or temporary apoplexy, succeeds to epileptic convulsions. 3. Hence when any violent pain afflicts us, of which we can neither avoid nor remove the cause, we soon learn to endeavour to alleviate it, by exerting some violent voluntary effort, as mentioned above; and are naturally induced to use those muscles for this purpose, which have been in the early periods of our lives most frequently or most powerfully exerted. Now the first muscles, which infants use most frequently, are those of respiration; and on this account we gain a habit of holding our breath, at the same time that we use great efforts to exclude it, for this purpose of alleviating unavoidable pain; or we press out our breath through a small aperture of the larynx, and scream violently, when the pain is greater than is relievable by the former mode of exertion. Thus children scream to relieve any pain either of body or mind, as from anger, or fear of being beaten. Hence it is curious to observe, that those animals, who have more frequently exerted their muscles of respiration violently, as in talking, barking, or grunting, as children, dogs, hogs, scream much more, when they are in pain, than those other animals, who use little or no language in their common modes of life; as horses, sheep, and cows. The next most frequent or most powerful efforts, which infants are first tempted to produce, are those with the muscles in biting hard substances; indeed the exertion of these muscles is very powerful in common mastication, as appears from the pain we receive, if a bit of bone is unexpectedly found amongst our softer food; and further appears from their acting to so great mechanical disadvantage, particularly when we bite with the incisores, or canine teeth; which are first formed, and thence are first used to violent exertion. Hence when a person is in great pain, the cause of which he cannot remove, he sets his teeth firmly together, or bites some substance between them with great vehemence, as another mode of violent exertion to produce a temporary relief. Thus we have a proverb where no help can be had in pain, "to grin and abide;" and the tortures of hell are said to be attended with "gnashing of teeth." Hence in violent spasmodic pains I have seen people bite not only their tongues, but their arms or fingers, or those of the attendants, or any object which was near them; and also strike, pinch, or tear, others or themselves, particularly the part of their own body, which is painful at the time. Soldiers, who die of painful wounds in battle, are said in Homer to bite the ground. Thus also in the bellon, or colica saturnina, the patients are said to bite their own flesh, and dogs in this disease to bite up the ground they lie upon. It is probable that the great endeavours to bite in mad dogs, and the violence of other mad animals, is owing to the same cause. 4. If the efforts of our voluntary motions are exerted with still greater energy for the relief of some disagreeable sensation, convulsions are produced; as the various kinds of epilepsy, and in some hysteric paroxysms. In all these diseases a pain, or disagreeable sensation is produced, frequently by worms, or acidity in the bowels, or by a diseased nerve in the side, or head, or by the pain of a diseased liver. In some constitutions a more intolerable degree of pain is produced in some part at a distance from the cause by sensitive association, as before explained; these pains in such constitutions arise to so great a degree, that I verily believe no artificial tortures could equal some, which I have witnessed; and am confident life would not have long been preserved, unless they had been soon diminished or removed by the universal convulsion of the voluntary motions, or by temporary madness. In some of the unfortunate patients I have observed, the pain has risen to an inexpressible degree, as above described, before the convulsions have supervened; and which were preceded by screaming, and grinning; in others, as in the common epilepsy, the convulsion has immediately succeeded the commencement of the disagreeable sensations; and as a stupor frequently succeeds the convulsions, they only seemed to remember that a pain at the stomach preceded the fit, or some other uneasy feel; or more frequently retained no memory at all of the immediate cause of the paroxysm. But even in this kind of epilepsy, where the patient does not recollect any preceding pain, the paroxysms generally are preceded by a quivering motion of the under jaw, with a biting of the tongue; the teeth afterwards become pressed together with vehemence, and the eyes are then convulsed, before the commencement of the universal convulsion; which are all efforts to relieve pain. The reason why these convulsive motions are alternately exerted and remitted was mentioned above, and in Sect. XII. 1. 3. when the exertions are such as give a temporary relief to the pain, which excites them, they cease for a time, till the pain is again perceived; and then new exertions are produced for its relief. We see daily examples of this in the loud reiterated laughter of some people; the pleasureable sensation, which excites this laughter, arises for a time so high as to change its name and become painful: the convulsive motions of the respiratory muscles relieve the pain for a time; we are, however, unwilling to lose the pleasure, and presently put a stop to this exertion, and immediately the pleasure recurs, and again as instantly rises into pain. All of us have felt the pain of immoderate laughter; children have been tickled into convulsions of the whole body; and others have died in the act of laughing; probably from a paralysis succeeding the long continued actions of the muscles of respiration. Hence we learn the reason, why children, who are so easily excited to laugh by the tickling of other people's fingers, cannot tickle themselves into laughter. The exertion of their hands in the endeavour to tickle themselves prevents the necessity of any exertion of the respiratory muscles to relieve the excess of pleasurable affection. See Sect. XVII. 3. 5. Chrysippus is recorded to have died laughing, when an ass was invited to sup with him. The same is related of one of the popes, who, when he was ill, saw a tame monkey at his bedside put on the holy thiara. Hall. Phys. T. III. p. 306. There are instances of epilepsy being produced by laughing recorded by Van Swieten, T. III. 402 and 308. And it is well known, that many people have died instantaneously from the painful excess of joy, which probably might have been prevented by the exertions of laughter. Every combination of ideas, which we attend to, occasions pain or pleasure; those which occasion pleasure, furnish either social or selfish pleasure, either malicious or friendly, or lascivious, or sublime pleasure; that is, they give us pleasure mixed with other emotions, or they give us unmixed pleasure, without occasioning any other emotions or exertions at the same time. This unmixed pleasure, if it be great, becomes painful, like all other animal motions from stimuli of every kind; and if no other exertions are occasioned at the same time, we use the exertion of laughter to relieve this pain. Hence laughter is occasioned by such wit as excites simple pleasure without any other emotion, such as pity, love, reverence. For sublime ideas are mixed with admiration, beautiful ones with love, new ones with surprise; and these exertions of our ideas prevent the action of laughter from being necessary to relieve the painful pleasure above described. Whence laughable wit consists of frivolous ideas, without connections of any consequence, such as puns on words, or on phrases, incongruous junctions of ideas; on which account laughter is so frequent in children. Unmixed pleasure less than that, which causes laughter, causes sleep, as in singing children to sleep, or in slight intoxication from wine or food. See Sect. XVIII. 12. 5. If the pains, or disagreeable sensations, above described do not obtain a temporary relief from these convulsive exertions of the muscles, those convulsive exertions continue without remission, and one kind of catalepsy is produced. Thus when a nerve or tendon produces great pain by its being inflamed or wounded, the patient sets his teeth firmly together, and grins violently, to diminish the pain; and if the pain is not relieved by this exertion, no relaxation of the maxillary muscles takes place, as in the convulsions above described, but the jaws remain firmly fixed together. This locked jaw is the most frequent instance of cataleptic spasm, because we are more inclined to exert the muscles subservient to mastication from their early obedience to violent efforts of volition. But in the case related in Sect. XIX. on Reverie, the cataleptic lady had pain in her upper teeth; and pressing one of her hands vehemently against her cheek-bone to diminish this pain, it remained in that attitude for about half an hour twice a day, till the painful paroxysm was over. I have this very day seen a young lady in this disease, (with which she has frequently been afflicted,) she began to-day with violent pain shooting from one side of the forehead to the occiput, and after various struggles lay on the bed with her fingers and wrists bent and stiff for about two hours; in other respects she seemed in a syncope with a natural pulse. She then had intervals of pain and of spasm, and took three grains of opium every hour till she had taken nine grains, before the pains and spasm ceased. There is, however, another species of fixed spasm, which differs from the former, as the pain exists in the contracted muscle, and would seem rather to be the consequence than the cause of the contraction, as in the cramp in the calf of the leg, and in many other parts of the body. In these spasms it should seem, that the muscle itself is first thrown into contraction by some disagreeable sensation, as of cold; and that then the violent pain is produced by the great contraction of the muscular fibres extending its own tendons, which are said to be sensible to extension only; and is further explained in Sect. XVIII. 15. 6. Many instances have been given in this work, where after violent motions excited by irritation, the organ has become quiescent to less, and even to the great irritation, which induced it into violent motion; as after looking long at the sun or any bright colour, they cease to be seen; and after removing from bright day-light into a gloomy room, the eye cannot at first perceive the objects, which stimulate it less. Similar to this is the syncope, which succeeds after the violent exertions of our voluntary motions, as after epileptic fits, for the power of volition acts in this case as the stimulus in the other. This syncope is a temporary palsy, or apoplexy, which ceases after a time, the muscles recovering their power of being excited into action by the efforts of volition; as the eye in the circumstance above mentioned recovers in a little time its power of seeing objects in a gloomy room; which were invisible immediately after coming out of a stronger light. This is owing to an accumulation of sensorial power during the inaction of those fibres, which were before accustomed to perpetual exertions, as explained in Sect. XII. 7. 1. A slighter degree of this disease is experienced by every one after great fatigue, when the muscles gain such inability to further action, that we are obliged to rest them for a while, or to summon a greater power of volition to continue their motions. In all the syncopes, which I have seen induced after convulsive fits, the pulse has continued natural, though the organs of sense, as well as the locomotive muscles, have ceased to perform their functions; for it is necessary for the perception of objects, that the external organs of sense should be properly excited by the voluntary power, as the eye-lids must be open, and perhaps the muscles of the eye put into action to distend, and thence give greater pellucidity to the cornea, which in syncope, as in death, appears flat and less transparent. The tympanum of the ear also seems to require a voluntary exertion of its muscles, to gain its due tension, and it is probable the other external organs of sense require a similar voluntary exertion to adapt them to the distinct perception of objects. Hence in syncope as in sleep, as the power of volition is suspended, no external objects are perceived. See Sect. XVIII. 5. During the time which the patient lies in a fainting fit, the spirit of animation becomes accumulated; and hence the muscles in a while become irritable by their usual stimulation, and the fainting fit ceases. See Sect. XII. 7. 1. 7. If the exertion of the voluntary motions has been still more energetic, the quiescence, which succeeds, is so complete, that they cannot again be excited into action by the efforts of the will. In this manner the palsy, and apoplexy (which is an universal palsy) are frequently produced after convulsions, or other violent exertions; of this I shall add a few instances. Platernus mentions some, who have died apoplectic from violent exertions in dancing; and Dr. Mead, in his Essay on Poisons, records a patient in the hydrophobia, who at one effort broke the cords which bound him, and at the same instant expired. And it is probable, that those, who have expired from immoderate laughter, have died from this paralysis consequent to violent exertion. Mrs. Scott of Stafford was walking in her garden in perfect health with her neighbour Mrs. ----; the latter accidentally fell into a muddy rivulet, and tried in vain to disengage herself by the assistance of Mrs. Scott's hand. Mrs. Scott exerted her utmost power for many minutes, first to assist her friend, and next to prevent herself from being pulled into the morass, as her distressed companion would not disengage her hand. After other assistance was procured by their united screams, Mrs. Scott walked to a chair about twenty yards from the brook, and was seized with an apoplectic stroke: which continued many days, and terminated in a total loss of her right arm, and her speech; neither of which she ever after perfectly recovered. It is said, that many people in Holland have died after skating too long or too violently on their frozen canals; it is probable the death of these, and of others, who have died suddenly in swimming, has been owing to this great quiescence or paralysis; which has succeeded very violent exertions, added to the concomitant cold, which has had greater effect after the sufferers had been heated and exhausted by previous exercise. I remember a young man of the name of Nairne at Cambridge, who walking on the edge of a barge fell into the river. His cousin and fellow-student of the same name, knowing the other could not swim, plunged into the water after him, caught him by his clothes, and approaching the bank by a vehement exertion propelled him safe to the land, but that instant, seized, as was supposed, by the cramp, or paralysis, sunk to rise no more. The reason why the cramp of the muscles, which compose the calf of the leg, is so liable to affect swimmers, is, because these muscles have very weak antagonists, and are in walking generally elongated again after their contraction by the weight of the body on the ball of the toe, which is very much greater than the resistance of the water in swimming. See Section XVIII. 15. It does not follow that every apoplectic or paralytic attack is immediately preceded by vehement exertion; the quiescence, which succeeds exertion, and which is not so great as to be termed paralysis, frequently recurs afterwards at certain periods; and by other causes of quiescence, occurring with those periods, as was explained in treating of the paroxysms of intermitting fevers; the quiescence at length, becomes so great as to be incapable of again being removed by the efforts of volition, and complete paralysis is formed. See Section XXXII. 3. 2. Many of the paralytic patients, whom I have seen, have evidently had diseased livers from the too frequent potation of spirituous liquors; some of them have had the gutta rosea on their faces and breasts; which has in some degree receded either spontaneously, or by the use of external remedies, and the paralytic stroke has succeeded; and as in several persons, who have drank much vinous spirits, I have observed epileptic fits to commence at about forty or fifty years of age, without any hereditary taint, from the stimulus, as I believed, of a diseased liver; I was induced to ascribe many paralytic cases to the same source; which were not evidently the effect of age, or of unacquired debility. And the account given before of dropsies, which very frequently are owing to a paralysis of the absorbent system, and are generally attendant on free drinkers of spirituous liquors, confirmed me in this opinion. The disagreeable irritation of a diseased liver produces exertions and consequent quiescence; these by the accidental concurrence of other causes of quiescence, as cold, solar or lunar periods, inanition, the want of their usual portion of spirit of wine, at length produces paralysis. This is further confirmed by observing, that the muscles, we most frequently, or most powerfully exert, are most liable to palsy; as those of the voice and of articulation, and of those paralytics which I have seen, a much greater proportion have lost the use of their right arm; which is so much more generally exerted than the left. I cannot dismiss this subject without observing, that after a paralytic stroke, if the vital powers are not much injured, that the patient has all the movements of the affected limb to learn over again, just as in early infancy; the limb is first moved by the irritation of its muscles, as in stretching, (of which a case was related in Section VII. 1. 3.) or by the electric concussion; afterwards it becomes obedient to sensation, as in violent danger or fear; and lastly, the muscles become again associated with volition, and gradually acquire their usual habits of acting together. Another phænomenon in palsies is, that when the limbs of one side are disabled, those of the other are in perpetual motion. This can only be explained from conceiving that the power of motion, whatever it is, or wherever it resides, and which is capable of being exhausted by fatigue, and accumulated in rest, is now less expended, whilst one half of the body is capable of receiving its usual proportion of it, and is hence derived with greater ease or in greater abundance into the limbs, which remain unaffected. II. 1. The excess or defect of voluntary exertion produces similar effects upon the sensual motions, or ideas of the mind, as those already mentioned upon the muscular fibres. Thus when any violent pain, arising from the defect of some peculiar stimulus, exists either in the muscular or sensual systems of fibres, and which cannot be removed by acquiring the defective stimulus; as in some constitutions convulsions of the muscles are produced to procure a temporary relief, so in other constitutions vehement voluntary exertions of the ideas of the mind are produced for the same purpose; for during this exertion, like that of the muscles, the pain either vanishes or is diminished: this violent exertion constitutes madness; and in many cases I have seen the madness take place, and the convulsions cease, and reciprocally the madness cease, and the convulsions supervene. See Section III. 5. 8. 2. Madness is distinguishable from delirium, as in the latter the patient knows not the place where he resides, nor the persons of his friends or attendants, nor is conscious of any external objects, except when spoken to with a louder voice, or stimulated with unusual force, and even then he soon relapses into a state of inattention to every thing about him. Whilst in the former he is perfectly sensible to every thing external, but has the voluntary powers of his mind intensely exerted on some particular object of his desire or aversion, he harbours in his thoughts a suspicion of all mankind, lest they should counteract his designs; and while he keeps his intentions, and the motives of his actions profoundly secret; he is perpetually studying the means of acquiring the object of his wish, or of preventing or revenging the injuries he suspects. 3. A late French philosopher, Mr. Helvetius, has deduced almost all our actions from this principle of their relieving us from the ennui or tædium vitæ; and true it is, that our desires or aversions are the motives of all our voluntary actions; and human nature seems to excel other animals in the more facil use of this voluntary power, and on that account is more liable to insanity than other animals. But in mania this violent exertion of volition is expended on mistaken objects, and would not be relieved, though we were to gain or escape the objects, that excite it. Thus I have seen two instances of madmen, who conceived that they had the itch, and several have believed they had the venereal infection, without in reality having a symptom of either of them. They have been perpetually thinking upon this subject, and some of them were in vain salivated with design of convincing them to the contrary. 4. In the minds of mad people those volitions alone exist, which are unmixed with sensation; immoderate suspicion is generally the first symptom, and want of shame, and want of delicacy about cleanliness. Suspicion is a voluntary exertion of the mind arising from the pain of fear, which it is exerted to relieve: shame is the name of a peculiar disagreeable sensation, see Fable of the Bees, and delicacy about cleanliness arises from another disagreeable sensation. And therefore are not found in the minds of maniacs, which are employed solely in voluntary exertions. Hence the most modest women in this disease walk naked amongst men without any kind of concern, use obscene discourse, and have no delicacy about their natural evacuations. 5. Nor are maniacal people more attentive to their natural appetites, or to the irritations which surround them, except as far as may respect their suspicions or designs; for the violent and perpetual exertions of their voluntary powers of mind prevents their perception of almost every other object, either of irritation or of sensation. Hence it is that they bear cold, hunger, and fatigue, with much greater pertinacity than in their sober hours, and are less injured by them in respect to their general health. Thus it is asserted by historians, that Charles the Twelfth of Sweden slept on the snow, wrapped only in his cloak, at the siege of Frederickstad, and bore extremes of cold and hunger, and fatigue, under which numbers of his soldiers perished; because the king was insane with ambition, but the soldier had no such powerful stimulus to preserve his system from debility and death. 6. Besides the insanities arising from exertions in consequence of pain, there is also a pleasurable insanity, as well as a pleasurable delirium; as the insanity of personal vanity, and that of religious fanaticism. When agreeable ideas excite into motion the sensorial power of sensation, and this again causes other trains of agreeable ideas, a constant stream of pleasurable ideas succeeds, and produces pleasurable delirium. So when the sensorial power of volition excites agreeable ideas, and the pleasure thus produced excites more volition in its turn, a constant flow of agreeable voluntary ideas succeeds; which when thus exerted in the extreme constitutes insanity. Thus when our muscular actions are excited by our sensations of pleasure, it is termed play; when they are excited by our volition, it is termed work; and the former of these is attended with less fatigue, because the muscular actions in play produce in their turn more pleasurable sensation; which again has the property of producing more muscular action. An agreeable instance of this I saw this morning. A little boy, who was tired with walking, begged of his papa to carry him. "Here," says the reverend doctor, "ride upon my gold-headed cane;" and the pleased child, putting it between his legs, gallopped away with delight, and complained no more of his fatigue. Here the aid of another sensorial power, that of pleasurable sensation, superadded vigour to the exertion of exhausted volition. Which could otherwise only have been excited by additional pain, as by the lash of slavery. On this account where the whole sensorial power has been exerted on the contemplation of the promised joys of heaven, the saints of all persecuted religions have borne the tortures of martyrdom with otherwise unaccountable firmness. 7. There are some diseases, which obtain at least a temporary relief from the exertions of insanity; many instances of dropsies being thus for a time cured are recorded. An elderly woman labouring with ascites I twice saw relieved for some weeks by insanity, the dropsy ceased for several weeks, and recurred again alternating with the insanity. A man afflicted with difficult respiration on lying down, with very irregular pulse, and oedematous legs, whom I saw this day, has for above a week been much relieved in respect to all those symptoms by the accession of insanity, which is shewn by inordinate suspicion, and great anger. In cases of common temporary anger the increased action of the arterial system is seen by the red skin, and increased pulse, with the immediate increase of muscular activity. A friend of mine, when he was painfully fatigued by riding on horseback, was accustomed to call up ideas into his mind, which used to excite his anger or indignation, and thus for a time at least relieved the pain of fatigue. By this temporary insanity, the effect of the voluntary power upon the whole of his system was increased; as in the cases of dropsy above mentioned, it would appear, that the increased action of the voluntary faculty of the sensorium affected the absorbent system, as well as the secerning one. 8. In respect to relieving inflammatory pains, and removing fever, I have seen many instances, as mentioned in Sect. XII. 2. 4. One lady, whom I attended, had twice at some years interval a locked jaw, which relieved a pain on her sternum with peripneumony. Two other ladies I saw, who towards the end of violent peripneumony, in which they frequently lost blood, were at length cured by insanity supervening. In the former the increased voluntary exertion of the muscles of the jaw, in the latter that of the organs of sense, removed the disease; that is, the disagreeable sensation, which had produced the inflammation, now excited the voluntary power, and these new voluntary exertions employed or expended the superabundant sensorial power, which had previously been exerted on the arterial system, and caused inflammation. Another case, which I think worth relating, was of a young man about twenty; he had laboured under an irritative fever with debility for three or four weeks, with very quick and very feeble pulse, and other usual symptoms of that species of typhus, but at this time complained much and frequently of pain of his legs and feet. When those who attended him were nearly in despair of his recovery, I observed with pleasure an insanity of mind supervene: which was totally different from delirium, as he knew his friends, calling them by their names, and the room in which he lay, but became violently suspicious of his attendants, and calumniated with vehement oaths his tender mother, who sat weeping by his bed. On this his pulse became slower and firmer, but the quickness did not for some time intirely cease, and he gradually recovered. In this case the introduction of an increased quantity of the power of volition gave vigour to those movements of the system, which are generally only actuated by the power of irritation, and of association. Another case I recollect of a young man, about twenty-five, who had the scarlet-fever, with very quick pulse, and an universal eruption on his skin, and was not without reason esteemed to be in great danger of his life. After a few days an insanity supervened, which his friends mistook for delirium, and he gradually recovered, and the cuticle peeled off. From these and a few other cases I have always esteemed insanity to be a favourable sign in fevers, and have cautiously distinguished it from delirium. III. Another mode of mental exertion to relieve pain, is by producing a train of ideas not only by the efforts of volition, as in insanity; but by those of sensation likewise, as in delirium and sleep. This mental effort is termed reverie, or somnambulation, and is described more at large in Sect. XIX. on that subject. But I shall here relate another case of that wonderful disease, which fell yesterday under my eye, and to which I have seen many analogous alienations of mind, though not exactly similar in all circumstances. But as all of them either began or terminated with pain or convulsion, there can be no doubt but that they are of epileptic origin, and constitute another mode of mental exertion to relieve some painful sensation. 1. Master A. about nine years old, had been seized at seven every morning for ten days with uncommon fits, and had had slight returns in the afternoon. They were supposed to originate from worms, and had been in vain attempted to be removed by vermifuge purges. As his fit was expected at seven yesterday morning, I saw him before that hour; he was asleep, seemed free from pain, and his pulse natural. About seven he began to complain of pain about his navel, or more to the left side, and in a few minutes had exertions of his arms and legs like swimming. He then for half an hour hunted a pack of hounds; as appeared by his hallooing, and calling the dogs by their names, and discoursing with the attendants of the chase, describing exactly a day of hunting, which (I was informed) he had witnessed a year before, going through all the most minute circumstances of it; calling to people, who were then present, and lamenting the absence of others, who were then also absent. After this scene he imitated, as he lay in bed, some of the plays of boys, as swimming and jumping. He then sung an English and then an Italian song; part of which with his eyes open, and part with them closed, but could not be awakened or excited by any violence, which it was proper to use. After about an hour he came suddenly to himself with apparent surprise, and seemed quite ignorant of any part of what had passed, and after being apparently well for half an hour, he suddenly fell into a great stupor, with slower pulse than natural, and a slow moaning respiration, in which he continued about another half hour, and then recovered. The sequel of this disease was favourable; he was directed one grain of opium at six every morning, and then to rise out of bed; at half past six he was directed fifteen drops of laudanum in a glass of wine and water. The first day the paroxysm became shorter, and less violent. The dose of opium was increased to one-half more, and in three or four days the fits left him. The bark and filings of iron were also exhibited twice a day; and I believe the complaint returned no more. 2. In this paroxysm it must be observed, that he began with pain, and ended with stupor, in both circumstances resembling a fit of epilepsy. And that therefore the exertions both of mind and body, both the voluntary ones, and those immediately excited by pleasurable sensation, were exertions to relieve pain. The hunting scene appeared to be rather an act of memory than of imagination, and was therefore rather a voluntary exertion, though attended with the pleasurable eagerness, which was the consequence of those ideas recalled by recollection, and not the cause of them. These ideas thus voluntarily recollected were succeeded by sensations of pleasure, though his senses were unaffected by the stimuli of visible or audible objects; or so weakly excited by them as not to produce sensation or attention. And the pleasure thus excited by volition produced other ideas and other motions in consequence of the sensorial power of sensation. Whence the mixed catenations of voluntary and sensitive ideas and muscular motions in reverie; which, like every other kind of vehement exertion, contribute to relieve pain, by expending a large quantity of sensorial power. Those fits generally commence during sleep, from whence I suppose they have been thought to have some connection with sleep, and have thence been termed Somnambulism; but their commencement during sleep is owing to our increased excitability by internal sensations at that time, as explained in Sect. XVIII. 14. and 15., and not to any similitude between reverie and sleep. 3. I was once concerned for a very elegant and ingenious young lady, who had a reverie on alternate days, which continued nearly the whole day; and as in her days of disease she took up the same kind of ideas, which she had conversed about on the alternate day before, and could recollect nothing of them on her well-day; she appeared to her friends to possess two minds. This case also was of epileptic kind, and was cured, with some relapses, by opium administered before the commencement of the paroxysm. 4. Whence it appears, that the methods of relieving inflammatory pains, is by removing all stimulus, as by venesection, cool air, mucilaginous diet, aqueous potation, silence, darkness. The methods of relieving pains from defect of stimulus is by supplying the peculiar stimulus required, as of food, or warmth. And the general method of relieving pain is by exciting into action some great part of the system for the purpose of expending a part of the sensorial power. This is done either by exertion of the voluntary ideas and muscles, as in insanity and convulsion; or by exerting both voluntary and sensitive motions, as in reverie; or by exciting the irritative motions by wine or opium internally, and by the warm bath or blisters externally; or lastly, by exciting the sensitive ideas by good news, affecting stories, or agreeable passions. * * * * * SECT. XXXV. DISEASES OF ASSOCIATION. I. 1. _Sympathy or consent of parts. Primary and secondary parts of an associated train of motions reciprocally affect each other. Parts of irritative trains of motion affect each other in four ways. Sympathies of the skin and stomach. Flushing of the face after a meal. Eruption of the small-pox on the face. Chilness after a meal._ 2. _Vertigo from intoxication._ 3. _Absorption from the lungs and pericardium by emetics. In vomiting the actions of the stomach are decreased, not increased. Digestion strengthened after an emetic. Vomiting from deficiency of sensorial power._ 4. _Dyspnoea from cold bathing. Slow pulse from digitalis. Death from gout in the stomach._ II. 1. _Primary and secondary parts of sensitive associations affect each other. Pain from gall-stone, from urinary stone, Hemicrania. Painful epilepsy._ 2. _Gout and red face from inflamed liver. Shingles from inflamed kidney._ 3. _Coryza from cold applied to the feet. Pleurisy. Hepatitis._ 4. _Pain of shoulders from inflamed liver._ III. _Diseases from the associations of ideas._ I. 1. Many synchronous and successive motions of our muscular fibres, and of our organs of sense, or ideas, become associated so as to form indissoluble tribes or trains of action, as shewn in Section X. on Associate Motions. Some constitutions more easily establish these associations, whether by voluntary, sensitive, or irritative repetitions, and some more easily lose them again, as shewn in Section XXXI. on Temperaments. When the beginning of such a train of actions becomes by any means disordered, the succeeding part is liable to become disturbed in consequence, and this is commonly termed sympathy or consent of parts by the writers of medicine. For the more clear understanding of these sympathies we must consider a tribe or train of actions as divided into two parts, and call one of them the primary or original motions, and the other the secondary or sympathetic ones. The primary and secondary parts of a train of irritative actions may reciprocally affect each other in four different manners. 1. They may both be exerted with greater energy than natural. 2. The former may act with greater, and the latter with less energy. 3. The former may act with less, and the latter with greater energy. 4. They may both act with less energy than natural. I shall now give an example of each kind of these modes of action, and endeavour to shew, that though the primary and secondary parts of these trains or tribes of motion are connected by irritative association, or their previous habits of acting together, as described in Sect. XX. on Vertigo. Yet that their acting with similar or dissimilar degrees of energy, depends on the greater or less quantity of sensorial power, which the primary part of the train expends in its exertions. The actions of the stomach constitute so important a part of the associations of both irritative and sensitive motions, that it is said to sympathize with almost every part of the body; the first example, which I shall adduce to shew that both the primary and secondary parts of a train of irritative associations of motion act with increased energy, is taken from the consent of the skin with this organ. When the action of the fibres of the stomach is increased, as by the stimulus of a full meal, the exertions of the cutaneous arteries of the face become increased by their irritative associations with those of the stomach, and a glow or flushing of the face succeeds. For the small vessels of the skin of the face having been more accustomed to the varieties of action, from their frequent exposure to various degrees of cold and heat become more easily excited into increased action, than those of the covered parts of our bodies, and thus act with more energy from their irritative or sensitive associations with the stomach. On this account in small-pox the eruption in consequence of the previous affection of the stomach breaks out a day sooner on the face than on the hands, and two days sooner than on the trunk, and recedes in similar times after maturation. But secondly, in weaker constitutions, that is, in those who possess less sensorial power, so much of it is expended in the increased actions of the fibres of the stomach excited by the stimulus of a meal, that a sense of chilness succeeds instead of the universal glow above mentioned; and thus the secondary part of the associated train of motions is diminished in energy, in consequence of the increased activity of the primary part of it. 2. Another instance of a similar kind, where the secondary part of the train acts with less energy in consequence of the greater exertions of the primary part, is the vertigo attending intoxication; in this circumstance so much sensorial power is expended on the stomach, and on its nearest or more strongly associated motions, as those of the subcutaneous vessels, and probably of the membranes of some internal viscera, that the irritative motions of the retina become imperfectly exerted from deficiency of sensorial power, as explained in Sect. XX. and XXI. 3. on Vertigo and on Drunkenness, and hence the staggering inebriate cannot completely balance himself by such indistinct vision. 3. An instance of the third circumstance, where the primary part of a train of irritative motions acts with less, and the secondary part with greater energy, may be observed by making the following experiment. If a person lies with his arms and shoulders out of bed, till they become cold, a temporary coryza or catarrh is produced; so that the passage of the nostrils becomes totally obstructed; at least this happens to many people; and then on covering the arms and shoulders, till they become warm, the passage of the nostrils ceases again to be obstructed, and a quantity of mucus is discharged from them. In this case the quiescence of the vessels of the skin of the arms and shoulders, occasioned by exposure to cold air, produces by irritative association an increased action of the vessels of the membrane of the nostrils; and the accumulation of sensorial power during the torpor of the arms and shoulders is thus expended in producing a temporary coryza or catarrh. Another instance may be adduced from the sympathy or consent of the motions of the stomach with other more distant links of the very extensive tribes or trains of irritative motions associated with them, described in Sect. XX. on Vertigo. When the actions of the fibres of the stomach are diminished or inverted, the actions of the absorbent vessels, which take up the mucus from the lungs, pericardium, and other cells of the body, become increased, and absorb the fluids accumulated in them with greater avidity, as appears from the exhibition of foxglove, antimony, or other emetics in cases of anasarca, attended with unequal pulse and difficult respiration. That the act of nausea and vomiting is a decreased exertion of the fibres of the stomach may be thus deduced; when an emetic medicine is administered, it produces the pain of sickness, as a disagreeable taste in the mouth produces the pain of nausea; these pains, like that of hunger, or of cold, or like those, which are usually termed nervous, as the head-ach or hemicrania, do not excite the organ into greater action; but in this case I imagine the pains of sickness or of nausea counteract or destroy the pleasurable sensation, which seems necessary to digestion, as shewn in Sect. XXXIII. 1. 1. The peristaltic motions of the fibres of the stomach become enfeebled by the want of this stimulus of pleasurable sensation, and in consequence stop for a time, and then become inverted; for they cannot become inverted without being previously stopped. Now that this inversion of the trains of motion of the fibres of the stomach is owing to the deficiency of pleasurable sensation is evinced from this circumstance, that a nauseous idea excited by words will produce vomiting as effectually us a nauseous drug. Hence it appears, that the act of nausea or vomiting expends less sensorial power than the usual peristaltic motions of the stomach in the digestion of our aliment; and that hence there is a greater quantity of sensorial power becomes accumulated in the fibres of the stomach, and more of it in consequence to spare for the action of those parts of the system, which are thus associated with the stomach, as of the whole absorbent series of vessels, and which are at the same time excited by their usual stimuli. From this we can understand, how after the operation of an emetic the stomach becomes more irritable and sensible to the stimulus, and the pleasure of food; since as the sensorial power becomes accumulated during the nausea and vomiting, the digestive power is afterwards exerted more forceably for a time. It should, however, be here remarked, that though vomiting is in general produced by the defect of this stimulus of pleasurable sensation, as when a nauseous drug is administered; yet in long continued vomiting, as in sea-sickness, or from habitual dram-drinking, it arises from deficiency of sensorial power, which in the former case is exhausted by the increased exertion of the irritative ideas of vision, and in the latter by the frequent application of an unnatural stimulus. 4. An example of the fourth circumstance above mentioned, where both the primary and secondary parts of a train of motions proceed with energy less than natural, may be observed in the dyspnoea, which occurs in going into a very cold bath, and which has been described and explained in Sect. XXXII. 3. 2. And by the increased debility of the pulsations of the heart and arteries during the operation of an emetic. Secondly, from the slowness and intermission of the pulsations of the heart from the incessant efforts to vomit occasioned by an overdose of digitalis. And thirdly, from the total stoppage of the motions of the heart, or death, in consequence of the torpor of the stomach, when affected with the commencement or cold paroxysm of the gout. See Sect. XXV. 17. II. 1. The primary and secondary parts of the trains of sensitive association reciprocally affect each other in different manners. 1. The increased sensation of the primary part may cease, when that of the secondary part commences. 2. The increased action of the primary part may cease, when that of the secondary part commences. 3. The primary part may have increased sensation, and the secondary part increased action. 4. The primary part may have increased action, and the secondary part increased sensation. Examples of the first mode, where the increased sensation of the primary part of a train of sensitive association ceases, when that of the secondary part commences, are not unfrequent; as this is the general origin of those pains, which continue some time without being attended with inflammation, such as the pain at the pit of the stomach from a stone at the neck of the gall-bladder, and the pain of strangury in the glans penis from a stone at the neck of the urinary bladder. In both these cases the part, which is affected secondarily, is believed to be much more sensible than the part primarily affected, as described in the catalogue of diseases, Class II. 1. 1. 11. and IV. 2. 2. 2. and IV. 2. 2. 4. The hemicrania, or nervous headach, as it is called, when it originates from a decaying tooth, is another disease of this kind; as the pain of the carious tooth always ceases, when the pain over one eye and temple commences. And it is probable, that the violent pains, which induce convulsions in painful epilepsies, are produced in the same manner, from a more sensible part sympathizing with a diseased one of less sensibility. See Catalogue of Diseases, Class IV. 2. 2. 8. and III. 1. 1. 6. The last tooth, or dens sapientiæ, of the upper jaw most frequently decays first, and is liable to produce pain over the eye and temple of that side. The last tooth of the under-jaw is also liable to produce a similar hemicrania, when it begins to decay. When a tooth in the upper-jaw is the cause of the headach, a slighter pain is sometimes perceived on the cheek-bone. And when a tooth in the lower-jaw is the cause of headach, a pain sometimes affects the tendons of the muscles of the neck, which are attached near the jaws. But the clavus hystericus, or pain about the middle of the parietal bone on one side of the head, I have seen produced by the second of the molares, or grinders, of the under-jaw; of which I shall relate the following case. See Class IV. 2. 2. 8. Mrs. ----, about 30 years of age, was seized with great pain about the middle of the right parietal bone, which had continued a whole day before I saw her, and was so violent as to threaten to occasion convulsions. Not being able to detect a decaying tooth, or a tender one, by examination with my eye, or by striking them with a tea-spoon, and fearing bad consequences from her tendency to convulsion, I advised her to extract the last tooth of the under-jaw on the affected side; which was done without any good effect. She was then directed to lose blood, and to take a brisk cathartic; and after that had operated, about 60 drops of laudanum were given her, with large doses of bark; by which the pain was removed. In about a fortnight she took a cathartic medicine by ill advice, and the pain returned with greater violence in the same place; and, before I could arrive, as she lived 30 miles from me, she suffered a paralytic stroke; which affected her limbs and her face on one side, and relieved the pain of her head. About a year afterwards I was again called to her on account of a pain as violent as before exactly on the same part of the other parietal bone. On examining her mouth I found the second molaris of the under-jaw on the side before affected was now decayed, and concluded, that this tooth had occasioned the stroke of the palsy by the pain and consequent exertion it had caused. On this account I earnestly entreated her to allow the sound molaris of the same jaw opposite to the decayed one to be extracted; which was forthwith done, and the pain of her head immediately ceased, to the astonishment of her attendants. In the cases above related of the pain existing in a part distant from the seat of the disease, the pain is owing to defect of the usual motions of the painful part. This appears from the coldness, paleness, and emptiness of the affected vessels, or of the extremities of the body in general, and from there being no tendency to inflammation. The increased action of the primary part of these associated motions, as of the hepatic termination of the bile-duct; from the stimulus of a gall-stone, or of the interior termination of the urethra from the stimulus of a stone in the bladder, or lastly, of a decaying tooth in hemicrania, deprives the secondary part of these associated motions, namely, the exterior terminations of the bile-duct or urethra, or the pained membranes of the head in hemicrania, of their natural share of sensorial power: and hence the secondary parts of these sensitive trains of association become pained from the deficiency of their usual motions, which is accompanied with deficiency of secretions and of heat. See Sect. IV. 5. XII. 5. 3. XXXIV. 1. Why does the pain of the primary part of the association cease, when that of the secondary part commences? This is a question of intricacy, but perhaps not inexplicable. The pain of the primary part of these associated trains of motion was owing to too great stimulus, as of the stone at the neck of the bladder, and was consequently caused by too great action of the pained part. This greater action than natural of the primary part of these associated motions, by employing or expending the sensorial power of irritation belonging to the whole associated train of motions, occasioned torpor, and consequent pain in the secondary part of the associated train; which was possessed of greater sensibility than the primary part of it. Now the great pain of the secondary part of the train, as soon as it commences, employs or expends the sensorial power of sensation belonging to the whole associated train of motions; and in consequence the motions of the primary part, though increased by the stimulus of an extraneous body, cease to be accompanied with pain or sensation. If this mode of reasoning be just it explains a curious fact, why when two parts of the body are strongly stimulated, the pain is felt only in one of them, though it is possible by voluntary attention it may be alternately perceived in them both. In the same manner, when two new ideas are presented to us from the stimulus of external bodies, we attend to but one of them at a time. In other words, when one set of fibres, whether of the muscles or organs of sense, contract so strongly as to excite much sensation; another set of fibres contracting more weakly do not excite sensation at all, because the sensorial power of sensation is pre-occupied by the first set of fibres. So we cannot will more than one effect at once, though by associations previously formed we can move many fibres in combination. Thus in the instances above related, the termination of the bile duct in the duodenum, and the exterior extremity of the urethra, are more sensible than their other terminations. When these parts are deprived of their usual motions by deficiency of sensorial power, as above explained, they become painful according to law the fifth in Section IV. and the less pain originally excited by the stimulus of concreted bile, or of a stone at their other extremities ceases to be perceived. Afterwards, however, when the concretions of bile, or the stone on the urinary bladder, become more numerous or larger, the pain from their increased stimulus becomes greater than the associated pain; and is then felt at the neck of the gall bladder or urinary bladder; and the pain of the glans penis, or at the pit of the stomach, ceases to be perceived. 2. Examples of the second mode, where the increased action of the primary part of a train of sensitive association ceases, when that of the secondary part commences, are also not unfrequent; as this is the usual manner of the translation of inflammations from internal to external parts of the system, such as when an inflammation of the liver or stomach is translated to the membranes of the foot, and forms the gout; or to the skin of the face, and forms the rosy drop; or when an inflammation of the membranes of the kidneys is translated to the skin of the loins, and forms one kind of herpes, called shingles; in these cases by whatever cause the original inflammation may have been produced, as the secondary part of the train of sensitive association is more sensible, it becomes exerted with greater violence than the first part of it; and by both its increased pain, and the increased motion of its fibres, so far diminishes or exhausts the sensorial power of sensation; that the primary part of the train being less sensible ceases both to feel pain, and to act with unnatural energy. 3. Examples of the third mode, where the primary part of a train of sensitive association of motions may experience increased sensation, and the secondary part increased action, are likewise not unfrequent; as it is in this manner that most inflammations commence. Thus, after standing some time in snow, the feet become affected with the pain of cold, and a common coryza, or inflammation of the membrane of the nostrils, succeeds. It is probable that the internal inflammations, as pleurisies, or hepatitis, which are produced after the cold paroxysm of fever, originate in the same manner from the sympathy of those parts with some others, which were previously pained from quiescence; as happens to various parts of the system during the cold fits of fevers. In these cases it would seem, that the sensorial power of sensation becomes accumulated during the pain of cold, as the torpor of the vessels occasioned by the defect of heat contributes to the increase or accumulation of the sensorial power of irritation, and that both these become exerted on some internal part, which was not rendered torpid by the cold which affected the external parts, nor by its association with them; or which sooner recovered its sensibility. This requires further consideration. 4. An example of the fourth mode, or where the primary part of a sensitive association of motions may have increased action, and the secondary part increased sensation, may be taken from the pain of the shoulder, which attends inflammation of the membranes of the liver, see Class IV. 2. 2. 9.; in this circumstance so much sensorial power seems to be expended in the violent actions and sensations of the inflamed membranes of the liver, that the membranes associated with them become quiescent to their usual stimuli, and painful in consequence. There may be other modes in which the primary and secondary parts of the trains of associated sensitive motions may reciprocally affect each other, as may be seen by looking over Class IV. in the catalogue of diseases; all which may probably be resolved into the plus and minus of sensorial power, but we have not yet had sufficient observations made upon them with a view to this doctrine. III. The associated trains of our ideas may have sympathies, and their primary and secondary parts affect each other in some manner similar to those above described; and may thus occasion various curious phenomena not yet adverted to, besides those explained in the Sections on Dreams, Reveries, Vertigo, and Drunkenness; and may thus disturb the deductions of our reasonings, as well as the streams of our imaginations; present us with false degrees of fear, attach unfounded value to trivial circumstances; give occasion to our early prejudices and antipathies; and thus embarrass the happiness of our lives. A copious and curious harvest might be reaped from this province of science, in which, however, I shall not at present wield my sickle. * * * * * SECT. XXXVI. OF THE PERIODS OF DISEASES. I. _Muscles excited by volition soon cease to contract, or by sensation, or by irritation, owing to the exhaustion of sensorial power. Muscles subjected to less stimulus have their sensorial power accumulated. Hence the periods of some fevers. Want of irritability after intoxication._ II. 1. _Natural actions catenated with daily habits of life._ 2. _With solar periods. Periods of sleep. Of evacuating the bowels._ 3. _Natural actions catenated with lunar periods. Menstruation. Venereal orgasm of animals. Barrenness._ III. _Periods of diseased animal actions from stated returns of nocturnal cold, from solar and lunar influence. Periods of diurnal fever, hectic fever, quotidian, tertian, quartan fever. Periods of gout, pleurisy, of fevers with arterial debility, and with arterial strength, Periods of rhaphania, of nervous cough, hemicrania, arterial hæmorrhages, hæmorrhoids, hæmoptoe, epilepsy, palsy, apoplexy, madness._ IV. _Critical days depend on lunar periods. Lunar periods in the small pox._ I. If any of our muscles be made to contract violently by the power of volition, as those of the fingers, when any one hangs by his hands on a swing, fatigue soon ensues; and the muscles cease to act owing to the temporary exhaustion of the spirit of animation; as soon as this is again accumulated in the muscles, they are ready to contract again by the efforts of volition. Those violent muscular actions induced by pain become in the same manner intermitted and recurrent; as in labour-pains, vomiting, tenesmus, strangury; owing likewise to the temporary exhaustion of the spirit of animation, as above mentioned. When any stimulus continues long to act with unnatural violence, so as to produce too energetic action of any of our moving organs, those motions soon cease, though the stimulus continues to act; as in looking long on a bright object, as on an inch-square of red silk laid on white paper in the sunshine. See Plate I. in Sect. III. 1. On the contrary, where less of the stimulus of volition, sensation, or irritation, have been applied to a muscle than usual; there appears to be an accumulation of the spirit of animation in the moving organ; by which it is liable to act with greater energy from less quantity of stimulus, than was previously necessary to excite it into so great action; as after having been immersed in snow the cutaneous vessels of our hands are excited into stronger action by the stimulus of a less degree of heat, than would previously have produced that effect. From hence the periods of some fever-fits may take their origin, either simply, or by their accidental coincidence with lunar and solar periods, or with the diurnal periods of heat and cold, to be treated of below; for during the cold fit at the commencement of a fever, from whatever cause that cold fit may have been induced, it follows, 1. That the spirit of animation must become accumulated in the parts, which exert during this cold fit less than their natural quantity of action. 2. If the cause producing the cold fit does not increase, or becomes diminished; the parts before benumbed or inactive become now excitable by smaller stimulus, and are thence thrown into more violent action than is natural; that is a hot fit succeeds the cold one. 3. By the energetic action of the system during the hot fit, if it continues long, an exhaustion of the spirit of animation takes place; and another cold fit is liable to succeed, from the moving system not being excitable into action from its usual stimulus. This inirritability of the system from a too great previous stimulus, and consequent exhaustion of sensorial power, is the cause of the general debility, and sickness, and head-ach, some hours after intoxication. And hence we see one of the causes of the periods of fever-fits; which however are frequently combined with the periods of our diurnal habits, or of heat and cold, or of solar or lunar periods. When besides the tendency to quiescence occasioned by the expenditure of sensorial power during the hot fit of fever, some other cause of torpor, as the solar or lunar periods, is necessary to the introduction of a second cold fit; the fever becomes of the intermittent kind; that is, there is a space of time intervenes between the end of the hot fit, and the commencement of the next cold one. But where no exteriour cause is necessary to the introduction of the second cold fit; no such interval of health intervenes; but the second cold fit commences, as soon as the sensorial power is sufficiently exhausted by the hot fit; and the fever becomes continual. II. 1. The following are natural animal actions, which are frequently catenated with our daily habits of life, as well as excited by their natural irritations. The periods of hunger and thirst become catenated with certain portions of time, or degrees of exhaustion, or other diurnal habits of life. And if the pain of hunger be not relieved by taking food at the usual time, it is liable to cease till the next period of time or other habits recur; this is not only true in respect to our general desire of food, but the kinds of it also are governed by this periodical habit; insomuch that beer taken to breakfast will disturb the digestion of those, who have been accustomed to tea; and tea taken at dinner will disagree with those, who have been accustomed to beer. Whence it happens, that those, who have weak stomachs, will be able to digest more food, if they take their meals at regular hours; because they have both the stimulus of the aliment they take, and the periodical habit, to assist their digestion. The periods of emptying the bladder are not only dependent on the acrimony or distention of the water in it, but are frequently catenated with external cold applied to the skin, as in cold bathing, or washing the hands; or with other habits of life, as many are accustomed to empty the bladder before going to bed, or into the house after a journey, and this whether it be full or not. Our times of respiration are not only governed by the stimulus of the blood in the lungs, or our desire of fresh air, but also by our attention to the hourly objects before us. Hence when a person is earnestly contemplating an idea of grief, he forgets to breathe, till the sensation in his lungs becomes very urgent; and then a sigh succeeds for the purpose of more forceably pushing forwards the blood, which is accumulated in the lungs. Our times of respiration are also frequently governed in part by our want of a steady support for the actions of our arms, and hands, as in threading a needle, or hewing wood, or in swimming; when we are intent upon these objects, we breathe at the intervals of the exertion of the pectoral muscles. 2. The following natural animal actions are influenced by solar periods. The periods of sleep and of waking depend much on the solar period, for we are inclined to sleep at a certain hour, and to awake at a certain hour, whether we have had more or less fatigue during the day, if within certain limits; and are liable to wake at a certain hour, whether we went to bed earlier or later, within certain limits. Hence it appears, that those who complain of want of sleep, will be liable to sleep better or longer, if they accustom themselves to go to rest, and to rise, at certain hours. The periods of evacuating the bowels are generally connected with some part of the solar day, as well as with the acrimony or distention occasioned by the feces. Hence one method of correcting costiveness is by endeavouring to establish a habit of evacuation at a certain hour of the day, as recommended by Mr. Locke, which may be accomplished by using daily voluntary efforts at those times, joined with the usual stimulus of the material to be evacuated. 3. The following natural animal actions are connected with lunar periods. 1. The periods of female menstruation are connected with lunar periods to great exactness, in some instances even to a few hours. These do not commence or terminate at the full or change, or at any other particular part of the lunation, but after they have commenced at any part of it, they continue to recur at that part with great regularity, unless disturbed by some violent circumstance, as explained in Sect. XXXII. No. 6. their return is immediately caused by deficient venous absorption, which is owing to the want of the stimulus, designed by nature, of amatorial copulation, or of the growing fetus. When the catamenia returns sooner than the period of lunation, it shows a tendency of the constitution to inirritability; that is to debility, or deficiency of sensorial power, and is to be relieved by small doses of steel and opium. The venereal orgasm of birds and quadrupeds seems to commence, or return about the most powerful lunations at the vernal or autumnal equinoxes; but if it be disappointed of its object, it is said to recur at monthly periods; in this respect resembling the female catamenia. Whence it is believed, that women are more liable to become pregnant at or about the time of their catamenia, than at the intermediate times; and on this account they are seldom much mistaken in their reckoning of nine lunar periods from the last menstruation; the inattention to this may sometimes have been the cause of supposed barrenness, and is therefore worth the observation of those, who wish to have children. III. We now come to the periods of diseased animal actions. The periods of fever-fits, which depend on the stated returns of nocturnal cold, are discussed in Sect. XXXII. 3. Those, which originate or recur at solar or lunar periods, are also explained in Section XXXII. 6. These we shall here enumerate; observing, however, that it is not more surprising, that the influence of the varying attractions of the sun and moon, should raise the ocean into mountains, than that it should affect the nice sensibilities of animal bodies; though the manner of its operation on them is difficult to be understood. It is probable however, that as this influence gradually lessens during the course of the day, or of the lunation, or of the year, some actions of our system become less and less; till at length a total quiescence of some part is induced; which is the commencement of the paroxysms of fever, of menstruation, of pain with decreased action of the affected organ, and of consequent convulsion. 1. A diurnal fever in some weak people is distinctly observed to come on towards evening, and to cease with a moist skin early in the morning, obeying the solar periods. Persons of weak constitutions are liable to get into better spirits at the access of the hot fit of this evening fever; and are thence inclined to sit up late; which by further enfeebling them increases the disease; whence they lose their strength and their colour. 2. The periods of hectic fever, supposed to arise from absorption of matter, obeys the diurnal periods like the above, having the exacerbescence towards evening, and its remission early in the morning, with sweats, or diarrhoea, or urine with white sediment. 3. The periods of quotidian fever are either catenated with solar time, and return at the intervals of twenty-four hours; or with lunar time, recurring at the intervals of about twenty-five hours. There is great use in knowing with what circumstances the periodical return or new morbid motions are conjoined, as the most effectual times of exhibiting the proper medicines are thus determined. So if the torpor, which ushers in an ague fit, is catenated with the lunar day: it is known, when the bark or opium must be given, so as to exert its principal effect about the time of the expected return. Solid opium should be given about an hour before the expected cold fit; liquid opium and wine about half an hour; the bark repeatedly for six or eight hours previous to the expected return. 4. The periods of tertian fevers, reckoned from the commencement of one cold fit to the commencement of the next cold fit, recur with solar intervals of forty-eight hours, or with lunar ones of about fifty hours. When these of recurrence begin one or two hours earlier than the solar period, it shews, that the torpor or cold fit is produced by less external influence; and therefore that it is more liable to degenerate into a fever with only remissions; so when menstruation recurs sooner than the period of lunation, it shews a tendency of the habit to torpor of inirritability. 5. The periods of quartan fevers return at solar intervals of seventy-two hours, or at lunar ones of about seventy-four hours and an half. This kind of ague appears most in moist cold autumns, and in cold countries replete with marshes. It is attended with greater debility, and its cold access more difficult to prevent. For where there is previously a deficiency of sensorial power, the constitution is liable to run into greater torpor from any further diminution of it; two ounces of bark and some steel should be given on the day before the return of the cold paroxysm, and a pint of wine by degrees a few hours before its return, and thirty drops of laudanum one hour before the expected cold fit. 6. The periods of the gout generally commence about an hour before sun-rise, which is usually the coldest part of the twenty-four hours. The greater periods of the gout seem also to observe the solar influence, returning about the same season of the year. 7. The periods of the pleurisy recur with exacerbation of the pain and fever about sun-set, at which time venesection is of most service. The same may be observed of the inflammatory rheumatism, and other fevers with arterial strength, which seem to obey solar periods; and those with debility seem to obey lunar ones. 8. The periods of fevers with arterial debility seem to obey the lunar day, having their access daily nearly an hour later; and have sometimes two accesses in a day, resembling the lunar effects upon the tides. 9. The periods of rhaphania, or convulsions of the limbs from rheumatic pains, seem to be connected with solar influence, returning at nearly the same hour for weeks together, unless disturbed by the exhibition of powerful doses of opium. So the periods of Tussis ferina, or violent cough with slow pulse, called nervous cough, recurs by solar periods. Five grains of opium, given at the time the cough commenced disturbed the period, from seven in the evening to eleven, at which time it regularly returned for some days, during which time the opium was gradually omitted. Then 120 drops of laudanum were given an hour before the access of the cough, and it totally ceased. The laudanum was continued a fortnight, and then gradually discontinued. 10. The periods of hemicrania, and of painful epilepsy, are liable to obey lunar periods, both in their diurnal returns, and in their greater periods of weeks, but are also induced by other exciting causes. 11. The periods of arterial hæmorrhages seem to return at solar periods about the same hour of the evening or morning. Perhaps the venous hæmorrhages obey the lunar periods, as the catamenia, and hæmorrhoids. 12. The periods of the hæmorrhoids, or piles, in some recur monthly, in others only at the greater lunar influence about the equinoxes. 13. The periods of hæmoptoe sometimes obey solar influence, recurring early in the morning for several days; and sometimes lunar periods, recurring monthly; and sometimes depend on our hours of sleep. See Class I. 2. 1. 9. 14. Many of the first periods of epileptic fits obey the monthly lunation with some degree of accuracy; others recur only at the most powerful lunations before the vernal equinox, and after the autumnal one; but when the constitution has gained a habit of relieving disagreeable sensations by this kind of exertion, the fit recurs from any slight cause. 15. The attack of palsy and apoplexy are known to recur with great frequency about the equinoxes. 16. There are numerous instances of the effect of the lunations upon the periods of insanity, whence the name of lunatic has been given to those afflicted with this disease. IV. The critical days, in which fevers are supposed to terminate, have employed the attention of medical philosophers from the days of Hippocrates to the present time. In whatever part of a lunation a fever commences, which owes either its whole cause to solar and lunar influence, or to this in conjunction with other causes; it would seem, that the effect would be the greatest at the full and new moon, as the tides rise highest at those times, and would be the least at the quadratures; thus if a fever-fit should commence at the new or full moon, occasioned by the solar and lunar attraction diminishing some chemical affinity of the particles of blood, and thence decreasing their stimulus on our sanguiferous system, as mentioned in Sect. XXXII. 6. this effect will daily decrease for the first seven days, and will then increase till about the fourteenth day, and will again decrease till about the twenty-first day, and increase again till the end of the lunation. If a fever-fit from the above cause should commence on the seventh day after either lunation, the reverse of the above circumstances would happen. Now it is probable, that those fevers, whose crisis or terminations are influenced by lunations, may begin at one or other of the above times, namely at the changes or quadratures; though sufficient observations have not been made to ascertain this circumstance. Hence I conclude, that the small-pox and measles have their critical days, not governed by the times required for certain chemical changes in the blood, which affect or alter the stimulus of the contagious matter, but from the daily increasing or decreasing effect of this lunar link of catenation, as explained in Section XVII. 3. 3. And as other fevers terminate most frequently about the seventh, fourteenth, twenty-first, or about the end of four weeks, when no medical assistance has disturbed their periods, I conclude, that these crises, or terminations, are governed by periods of the lunations; though we are still ignorant of their manner of operation. In the distinct small-pox the vestiges of lunation are very apparent, after inoculation a quarter of a lunation precedes the commencement of the fever, another quarter terminates with the complete eruption, another quarter with the complete maturation, and another quarter terminates the complete absorption of a material now rendered inoffensive to the constitution. * * * * * SECT. XXXVII. OF DIGESTION, SECRETION, NUTRITION. I. _Crystals increase by the greater attraction of their sides. Accretion by chemical precipitations, by welding, by pressure, by agglutination._ II. _Hunger, digestion, why it cannot be imitated out of the body. Lacteals absorb by animal selection or appetency._ III. _The glands and pores absorb nutritious particles by animal selection. Organic particles of Buffon. Nutrition applied at the time of elongation of fibres. Like inflammation._ IV. _It seems easier to have preserved animals than to reproduce them. Old age and death from inirritability. Three causes of this. Original fibres of the organs of sense and muscles unchanged._ V. _Art of producing long life._ I. The larger crystals of saline bodies may be conceived to arise from the combination of smaller crystals of the same form, owing to the greater attractions of their sides than of their angles. Thus if four cubes were floating in a fluid, whose friction or resistance is nothing, it is certain the sides of these cubes would attract each other stronger than their angles; and hence that these four smaller cubes would so arrange themselves as to produce one larger one. There are other means of chemical accretion, such as the depositions of dissolved calcareous or siliceous particles, as are seen in the formation of the stalactites of limestone in Derbyshire, or of calcedone in Cornwall. Other means of adhesion are produced by heat and pressure, as in the welding of iron-bars; and other means by simple pressure, as in forcing two pieces of caoutchou, or elastic gum, to adhere; and lastly, by the agglutination of a third substance penetrating the pores of the other two, as in the agglutination of wood by means of animal gluten. Though the ultimate particles of animal bodies are held together during life, as well as after death, by their specific attraction of cohesion, like all other matter; yet it does not appear, that their original organization was produced by chemical laws, and their production and increase must therefore only be looked for from the laws of animation. II. When the pain of hunger requires relief, certain parts of the material world, which surround us, when applied to our palates, excite into action the muscles of deglutition; and the material is swallowed into the stomach. Here the new aliment becomes mixed with certain animal fluids, and undergoes a chemical process, termed digestion; which however chemistry has not yet learnt to imitate out of the bodies of living animals or vegetables. This process seems very similar to the saccharine process in the lobes of farinaceous seeds, as of barley, when it begins to germinate; except that, along with the sugar, oil and mucilage are also produced; which form the chyle of animals, which is very similar to their milk. The reason, I imagine, why this chyle-making, or saccharine process, has not yet been imitated by chemical operations, is owing to the materials being in such a situation in respect to warmth, moisture, and motion; that they will immediately change into the vinous or acetous fermentation; except the new sugar be absorbed by the numerous lacteal or lymphatic vessels, as soon as it is produced; which is not easy to imitate in the laboratory. These lacteal vessels have mouths, which are irritated into action by the stimulus of the fluid, which surrounds them; and by animal selection, or appetency, they absorb such part of the fluid as is agreeable to their palate; those parts, for instance, which are already converted into chyle, before they have time to undergo another change by a vinous or acetous fermentation. This animal absorption of fluid is almost visible to the naked eye in the action of the puncta lacrymalia; which imbibe the tears from the eye, and discharge them again into the nostrils. III. The arteries constitute another reservoir of a changeful fluid; from which, after its recent oxygenation in the lungs, a further animal selection of various fluids is absorbed by the numerous glands; these select their respective fluids from the blood, which is perpetually undergoing a chemical change; but the selection by these glands, like that of the lacteals, which open their mouths into the digesting aliment in the stomach, is from animal appetency, not from chemical affinity; secretion cannot therefore be imitated in the laboratory, as it consists in a selection of part of a fluid during the chemical change of that fluid. The mouths of the lacteals, and lymphatics, and the ultimate terminations of the glands, are finer than can easily be conceived; yet it is probable, that the pores, or interstices of the parts, or coats, which constitute these ultimate vessels, may still have greater tenuity; and that these pores from the above analogy must posses a similar power of irritability, and absorb by their living energy the particles of fluid adapted to their purposes, whether to replace the parts abraded or dissolved, or to elongate and enlarge themselves. Not only every kind of gland is thus endued with its peculiar appetency, and selects the material agreeable to its taste from the blood, but every individual pore acquires by animal selection the material, which it wants; and thus nutrition seems to be performed in a manner so similar to secretion; that they only differ in the one retaining, and the other parting again with the particles, which they have selected from the blood. This way of accounting for nutrition from stimulus, and the consequent animal selection of particles, is much more analogous to other phenomena of the animal microcosm, than by having recourse to the microscopic animalcula, or organic particles of Buffon, and Needham; which being already compounded must themselves require nutritive particles to continue their own existence. And must be liable to undergo a change by our digestive or secretory organs; otherwise mankind would soon resemble by their theory the animals, which they feed upon. He, who is nourished by beef or venison, would in time become horned; and he, who feeds on pork or bacon, would gain a nose proper for rooting into the earth, as well as for the perception of odours. The whole animal system may be considered as consisting of the extremities of the nerves, or of having been produced from them; if we except perhaps the medullary part of the brain residing in the head and spine, and in the trunks of the nerves. These extremities of the nerves are either of those of locomotion, which are termed muscular fibres; or of those of sensation, which constitute the immediate organs of sense, and which have also their peculiar motions. Now as the fibres, which constitute the bones and membranes, possessed originally sensation and motion; and are liable again to possess them, when they become inflamed; it follows, that those were, when first formed, appendages to the nerves of sensation or locomotion, or were formed from them. And that hence all these solid parts of the body, as they have originally consisted of extremities of nerves, require an apposition of nutritive particles of a similar kind, contrary to the opinion of Buffon and Needham above recited. Lastly, as all these filaments have possessed, or do possess, the power of contraction, and of consequent inertion or elongation; it seems probable, that the nutritive particles are applied during their times of elongation; when their original constituent particles are removed to a greater distance from each other. For each muscular or sensual fibre may be considered as a row or string of beads; which approach, when in contraction, and recede during its rest or elongation; and our daily experience shews us, that great action emaciates the system, and that it is repaired during rest. Something like this is seen out of the body; for if a hair, or a single untwisted fibre of flax or silk, be soaked in water; it becomes longer and thicker by the water, which is absorbed into its pores. Now if a hair could be supposed to be thus immersed in a solution of particles similar to those, which compose it; one may imagine, that it might be thus increased in weight and magnitude; as the particles of oak-bark increase the substance of the hides of beasts in the process of making leather. I mention these not as philosophic analogies, but as similes to facilitate our ideas, how an accretion of parts may be effected by animal appetences, or selections, in a manner somewhat similar to mechanical or chemical attractions. If those new particles of matter, previously prepared by digestion and sanguification, only supply the places of those, which have been abraded by the actions of the system, it is properly termed nutrition. If they are applied to the extremities of the nervous fibrils, or in such quantity as to increase the length or crassitude of them, the body becomes at the same time enlarged, and its growth is increased, as well as its deficiences repaired. In this last case something more than a simple apposition or selection of particles seems to be necessary; as many parts of the system during its growth are caused to recede from those, with which they were before in contact; as the ends of the bones, or cartilages, recede from each other, as their growth advances: this process resembles inflammation, as appears in ophthalmy, or in the production of new flesh in ulcers, where old vessels are enlarged, and new ones produced; and like that is attended with sensation. In this situation the vessels become distended with blood, and acquire greater sensibility, and may thus be compared to the erection of the penis, or of the nipples of the breasts of women; while new particles become added at the same time; as in the process of nutrition above described. When only the natural growth of the various parts of the body are produced, a pleasurable sensation attends it, as in youth, and perhaps in those, who are in the progress of becoming fat. When an unnatural growth is the consequence, as in inflammatory diseases, a painful sensation attends the enlargement of the system. IV. This apposition of new parts, as the old ones disappear, selected from the aliment we take, first enlarges and strengthens our bodies for twenty years, for another twenty years it keeps us in health and vigour, and adds strength and solidity to the system; and then gradually ceases to nourish us properly, and for another twenty years we gradually sink into decay, and finally cease to act, and to exist. On considering this subject one should have imagined at first view, that it might have been easier for nature to have supported her progeny for ever in health and life, than to have perpetually reproduced them by the wonderful and mysterious process of generation. But it seems our bodies by long habit cease to obey the stimulus of the aliment, which should support us. After we have acquired our height and solidity we make no more new parts, and the system obeys the irritations, sensations, volitions; and associations, with, less and less energy, till the whole sinks into inaction. Three causes may conspire to render our nerves less excitable, which have been already mentioned, 1. If a stimulus be greater than natural, it produces too great an exertion of the stimulated organ, and in consequence exhausts the spirit of animation; and the moving organ ceases to act, even though the stimulus be continued. And though rest will recruit this exhaustion, yet some degree of permanent injury remains, as is evident after exposing the eyes long to too strong a light. 2. If excitations weaker than natural be applied, so as not to excite the organ into action, (as when small doses of aloe or rhubarb are exhibited,) they may be gradually increased, without exciting the organ into action; which will thus acquire a habit of disobedience to the stimulus; thus by increasing the dose by degrees, great quantities of opium or wine may be taken without intoxication. See Sect. XII. 3. 1. 3. Another mode, by which life is gradually undermined, is when irritative motions continue to be produced in consequence of stimulus, but are not succeeded by sensation; hence the stimulus of contagious matter is not capable of producing fever a second time, because it is not succeeded by sensation. See Sect. XII. 3. 6. And hence, owing to the want of the general pleasurable sensation, which ought to attend digestion and glandular secretion, an irksomeness of life ensues; and, where this is in greater excess, the melancholy of old age occurs, with torpor or debility. From hence I conclude, that it is probable that the fibrillæ, or moving filaments at the extremities of the nerves of sense, and the fibres which constitute the muscles (which are perhaps the only parts of the system that are endued with contractile life) are not changed, as we advance in years, like the other parts of the body; but only enlarged or elongated with our growth; and in consequence they become less and less excitable into action. Whence, instead of gradually changing the old animal, the generation of a totally new one becomes necessary with undiminished excitability; which many years will continue to acquire new parts, or new solidity, and then losing its excitability in time, perish like its parent. V. From this idea the art of preserving long health and life may be deduced; which must consist in using no greater stimulus, whether of the quantity or kind of our food and drink, or of external circumstances, such as heat, and exercise, and wakefulness, than is sufficient to preserve us in vigour; and gradually, as we grow old to increase the stimulus of our aliment, as the irritability of our system increases. The debilitating effects ascribed by the poet MARTIAL to the excessive use of warm bathing in Italy, may with equal propriety be applied to the warm rooms of England; which, with the general excessive stimulus of spirituous or fermented liquors, and in some instances of immoderate venery, contribute to shorten our lives. _Balnea, vina, venus, corrumpunt corpora nostra_, _At faciunt vitam balnea, vina, venus!_ Wine, women, warmth, against our lives combine; But what is life without warmth, women, wine! * * * * * SECT. XXXVIII. OF THE OXYGENATION OF THE BLOOD IN THE LUNGS, AND IN THE PLACENTA. I. _Blood absorbs oxygene from the air, whence phosphoric acid changes its colour, gives out heat, and some phlogistic material, and acquires an ethereal spirit, which is dissipated in fibrous motion._ II. _The placenta is a pulmonary organ like the gills of fish. Oxygenation of the blood from air, from water, by lungs, by gills, by the placenta; necessity of this oxygenation to quadrupeds, to fish, to the foetus in utero. Placental vessels inserted into the arteries of the mother. Use of cotyledons in cows. Why quadrupeds have not sanguiferous lochia. Oxygenation of the chick in the egg, of feeds._ III. _The liquor amnii is not excrementitious. It is nutritious. It is found in the esophagus and stomach, and forms the meconium. Monstrous births without heads. Question of Dr. Harvey._ I. From the recent discoveries of many ingenious philosophers it appears, that during respiration the blood imbibes the vital part of the air, called oxygene, through the membranes of the lungs; and that hence respiration may be aptly compared to a slow combustion. As in combustion the oxygene of the atmosphere unites with some phlogistic or inflammable body, and forms an acid (as in the production of vitriolic acid from sulphur, or carbonic acid from charcoal,) giving out at the same time a quantity of the matter of heat; so in respiration the oxygene of the air unites with the phlogistic part of the blood, and probably produces phosphoric or animal acid, changing the colour of the blood from a dark to a bright red; and probably some of the matter of heat is at the same time given out according to the theory of Dr. Crawford. But as the evolution of heat attends almost all chemical combinations, it is probable, that it also attends the secretions of the various fluids from the blood; and that the constant combinations or productions of new fluids by means of the glands constitute the more general source of animal heat; this seems evinced by the universal evolution of the matter of heat in the blush of shame or of anger; in which at the same time an increased secretion of the perspirable matter occurs; and the partial evolution of it from topical inflammations, as in gout or rheumatism, in which there is a secretion of new blood-vessels. Some medical philosophers have ascribed the heat of animal bodies to the friction of the particles of the blood against the sides of the vessels. But no perceptible heat has ever been produced by the agitation of water, or oil, or quicksilver, or other fluids; except those fluids have undergone at the same time some chemical change, as in agitating milk or wine, till they become sour. Besides the supposed production of phosphoric acid, and change of colour of the blood, and the production of carbonic acid, there would appear to be something of a more subtile nature perpetually acquired from the atmosphere; which is too fine to be long contained in animal vessels, and therefore requires perpetual renovation; and without which life cannot continue longer than a minute or two; this ethereal fluid is probably secreted from the blood by the brain, and perpetually dissipated in the actions of the muscles and organs of sense. That the blood acquires something from the air, which is immediately necessary to life, appears from an experiment of Dr. Hare (Philos. Transact. abridged, Vol. III. p. 239.) who found, "that birds, mice, &c. would live as long again in a vessel, where he had crowded in double the quantity of air by a condensing engine, than they did when confined in air of the common density." Whereas if some kind of deleterious vapour only was exhaled from the blood in respiration; the air, when condensed into half its compass, could not be supposed to receive so much of it. II. Sir Edward Hulse, a physician of reputation at the beginning of the present century, was of opinion, that the placenta was a respiratory organ, like the gills of fish; and not an organ to supply nutriment to the foetus; as mentioned in Derham's Physico-theology. Many other physicians seem to have espoused the same opinion, as noticed by Haller. Elem. Physiologiæ, T. 1. Dr. Gipson published a defence of this theory in the Medical Essays of Edinburgh, Vol. I. and II. which doctrine is there controverted at large by the late Alexander Monro; and since that time the general opinion has been, that the placenta is an organ of nutrition only, owing perhaps rather to the authority of so great a name, than to the validity of the arguments adduced in its support. The subject has lately been resumed by Dr. James Jeffray, and by Dr. Forester French, in their inaugural dissertations at Edinburgh and at Cambridge; who have defended the contrary opinion in an able and ingenious manner; and from whose Theses I have extracted many of the following remarks. First, by the late discoveries of Dr. Priestley, M. Lavoisier, and other philosophers, it appears, that the basis of atmospherical air, called oxygene, is received by the blood through the membranes of the lungs; and that by this addition the colour of the blood is changed from a dark to a light red. Secondly, that water possesses oxygene also as a part of its composition, and contains air likewise in its pores; whence the blood of fish receives oxygene from the water, or from the air it contains, by means of their gills, in the same manner as the blood is oxygenated in the lungs of air-breathing animals; it changes its colour at the same time from a dark to a light red in the vessels of their gills, which constitute a pulmonary organ adapted to the medium in which they live. Thirdly, that the placenta consists of arteries carrying the blood to its extremities, and a vein bringing it back, resembling exactly in structure the lungs and gills above mentioned; and that the blood changes its colour from a dark to a light red in passing through these vessels. This analogy between the lungs and gills of animals, and the placenta of the fetus, extends through a great variety of other circumstances; thus air-breathing creatures and fish can live but a few minutes without air or water; or when they are confined in such air or water, as has been spoiled by their own respiration; the same happens to the fetus, which, as soon as the placenta is separated from the uterus, must either expand its lungs, and receive air, or die. Hence from the structure, as well as the use of the placenta, it appears to be a respiratory organ, like the gills of fish, by which the blood in the fetus becomes oxygenated. From the terminations of the placental vessels not being observed to bleed after being torn from the uterus, while those of the uterus effuse a great quantity of florid arterial blood, the terminations of the placental vessels would seem to be inserted into the arterial ones of the mother; and to receive oxygenation from the passing currents of her blood through their coats or membranes; which oxygenation is proved by the change of the colour of the blood from dark to light red in its passage from the placental arteries to the placental vein. The curious structure of the cavities or lacunæ of the placenta, demonstrated by Mr. J. Hunter, explain this circumstance. That ingenious philosopher has shewn, that there are numerous cavities of lacunæ formed on that side of the placenta, which is in contact with the uterus; those cavities or cells are filled with blood from the maternal arteries, which open into them; which blood is again taken up by the maternal veins, and is thus perpetually changed. While the terminations of the placental arteries and veins are spread in fine reticulation on the sides of these cells. And thus, as the growing fetus requires greater oxygenation, an apparatus is produced resembling exactly the air-cells of the lungs. In cows, and other ruminating animals, the internal surface of the uterus is unequal like hollow cups, which have been called cotyledons; and into these cavities the prominencies of the numerous placentas, with which the fetus of those animals is furnished, are inserted, and strictly adhere; though they may be extracted without effusion of blood. These inequalities of the uterus, and the numerous placentas in consequence, seem to be designed for the purpose of expanding a greater surface for the terminations of the placental vessels for the purpose of receiving oxygenation from the uterine ones; as the progeny of this class of animals are more completely formed before their nativity, than that of the carnivorous classes, and must thence in the latter weeks of pregnancy require greater oxygenation. Thus calves and lambs can walk about in a few minutes after their birth; while puppies and kittens remain many days without opening their eyes. And though on the separation of the cotyledons of ruminating animals no blood is effused, yet this is owing clearly to the greater power of contraction of their uterine lacunæ or alveoli. See Medical Essays, Vol. V. page 144. And from the same cause they are not liable to a sanguiferous menstruation. The necessity of the oxygenation of the blood in the fetus is farther illustrated by the analogy of the chick in the egg; which appears to have its blood oxygenated at the extremities of the vessels surrounding the yolk; which are spread on the air-bag at the broad end of the egg, and may absorb oxygene through that moist membrane from the air confined behind it; and which is shewn by experiments in the exhausted receiver to be changeable though the shell. This analogy may even be extended to the growing seeds of vegetables; which were shewn by Mr. Scheele to require a renovation of the air over the water, in which they were confined. Many vegetable seeds are surrounded with air in their pods or receptacles, as peas, the fruit of staphylea, and lichnis vesicaria; but it is probable, that those seeds, after they are shed, as well as the spawn of fish, by the situation of the former on or near the moist and aerated surface of the earth, and of the latter in the ever-changing and ventilated water, may not be in need of an apparatus for the oxygenation of their first blood, before the leaves of one, and the gills of the other, are produced for this purpose. III. 1. There are many arguments, besides the strict analogy between the liquor amnii and the albumen ovi, which shew the former to be a nutritive fluid; and that the fetus in the latter months of pregnancy takes it into its stomach; and that in consequence the placenta is produced for some other important purpose. First, that the liquor amnii is not an excrementitious fluid is evinced, because it is found in greater quantity, when the fetus is young, decreasing after a certain period till birth. Haller asserts, "that in some animals but a small quantity of this fluid remains at the birth. In the eggs of hens it is consumed on the eighteenth day, so that at the exclusion of the chick scarcely any remains. In rabbits before birth there is none." Elem. Physiol. Had this been an excrementitious fluid, the contrary would probably have occurred. Secondly, the skin of the fetus is covered with a whitish crust or pellicle, which would seem to preclude any idea of the liquor amnii being produced by any exsudation of perspirable matter. And it cannot consist of urine, because in brute animals the urachus passes from the bladder to the alantois for the express purpose of carrying off that fluid; which however in the human fetus seems to be retained in the distended bladder, as the feces are accumulated in the bowels of all animals. 2. The nutritious quality of the liquid, which surrounds the fetus, appears from the following considerations. 1. It is coagulable by heat, by nitrous acid, and by spirit of wine, like milk, serum of blood, and other fluids, which daily experience evinces to be nutritious. 2. It has a saltish taste according to the accurate Baron Haller, not unlike the whey of milk, which it even resembles in smell. 3. The white of the egg which constitutes the food of the chick, is shewn to be nutritious by our daily experience; besides the experiment of its nutritious effects mentioned by Dr. Fordyce in his late Treatise on Digestion, p. 178; who adds, that it much resembles the essential parts of the serum of blood. 3. A fluid similar to the fluid, with which the fetus is surrounded, except what little change may be produced by a beginning digestion, is found in the stomach of the fetus; and the white of the egg is found, in the same manner in the stomach of the chick. Numerous hairs, similar to those of its skin, are perpetually found among the contents of the stomach in new-born calves; which must therefore have licked themselves before their nativity. Blasii Anatom. See Sect. XVI. 2. on Instinct. The chick in the egg is seen gently to move in its surrounding fluid, and to open and shut its mouth alternately. The same has been observed in puppies. Haller's El. Phys. I. 8. p. 201. A column of ice has been seen to reach down the oesophagus from the mouth to the stomach in a frozen fetus; and this ice was the liquor amnii frozen. The meconium, or first fæces, in the bowels of new-born infants evince, that something has been digested; and what could this be but the liquor amnii together with the recrements of the gastric juice and gall, which were necessary for its digestion? There have been recorded some monstrous births of animals without heads, and consequently without mouths, which seem to have been delivered on doubtful authority, or from inaccurate observation. There are two of such monstrous productions however better attested; one of a human fetus, mentioned by Gipson in the Scots Medical Essays; which having the gula impervious was furnished with an aperture into the wind-pipe, which communicated below into the gullet; by means of which the liquor amnii might be taken into the stomach before nativity without danger of suffocation, while the fetus had no occasion to breathe. The other monstrous fetus is described by Vander Wiel, who asserts, that he saw a monstrous lamb, which had no mouth; but instead of it was furnished with an opening in the lower part of the neck into the stomach. Both these instances evidently favour the doctrine of the fetus being nourished by the mouth; as otherwise there had been no necessity for new or unnatural apertures into the stomach, when the natural ones were deficient? From these facts and observations we may safely infer, that the fetus in the womb is nourished by the fluid which surrounds it; which during the first period of gestation is absorbed by the naked lacteals; and is afterwards swallowed into the stomach and bowels, when these organs are perfected; and lastly that the placenta is an organ for the purpose of giving due oxygenation to the blood of the fetus; which is more necessary, or at least more frequently necessary, than even the supply of food. The question of the great Harvey becomes thus easily answered. "Why is not the fetus in the womb suffocated for want of air, when it remains there even to the tenth month without respiration: yet if it be born in the seventh or eighth month, and has once respired, it becomes immediately suffocated for want of air, if its respiration be obstructed?" For further information on this subject, the reader is referred to the Tentamen Medicum of Dr. Jeffray, printed at Edinburgh in 1786. And it is hoped that Dr. French will some time give his theses on this subject to the public. * * * * * SECT. XXXIX. OF GENERATION. Felix, qui causas altà caligine mersas Pandit, et evolvit tenuissima vincula rerum. I. _Habits of acting and feeling of individuals attend the soul into a future life, and attend the new embryon at the time of its production. The new speck of entity absorbs nutriment, and receives oxygene. Spreads the terminations of its vessels on cells, which communicate with the arteries of the uterus; sometimes with those of the peritoneum. Afterwards it swallows the liquor amnii, which it produces by its irritation from the uterus, or peritoneum. Like insects in the heads of calves and sheep. Why the white of egg is of two consistencies. Why nothing is found in quadrupeds similar to the yolk, nor in most vegetable seeds._ II. 1. _Eggs of frogs and fish impregnated out of their bodies. Eggs of fowls which are not fecundated, contain only the nutriment for the embryon. The embryon is produced by the male, and the nutriment by the female. Animalcula in semine. Profusion of nature's births._ 2. _Vegetables viviparous. Buds and bulbs have each a father but no mother. Vessels of the leaf and bud inosculate. The paternal offspring exactly resembles the parent._ 3. _Insects impregnated for six generations. Polypus branches like buds. Creeping roots. Viviparous flowers. Tænia, volvox. Eve from Adam's rib. Semen not a stimulus to the egg._ III. 1. _Embryons not originally created within other embryons. Organized matter is not so minute._ 2. _All the parts of the embryon are not formed in the male parent. Crabs produce their legs, worms produce their heads and tails. In wens, cancers, and inflammations, new vessels are formed. Mules partake of the forms of both parents. Hair and nails grow by elongation, not by distention._ 3. _Organic particles of Buffon._ IV. 1. _Rudiment of the embryon a simple living filament, becomes a living ring, and then a living tube._ 2. _It acquires irritabilities, and sensibilities with new organizations, as in wounded snails, polypi, moths, gnats, tadpoles. Hence new parts are acquired by addition not by distention._ 3. _All parts of the body grow if not confined._ 4. _Fetuses deficient at their extremities, or have a duplicature of parts. Monstrous births. Double parts of vegetables._ 5. _Mules cannot be formed by distention of the seminal ens._ 6. _Families of animals from a mixture of their orders. Mules imperfect._ 7. _Animal appetency like chemical affinity. Vis fabricatrix and medicatrix of nature._ 8. _The changes of animals before and after nativity. Similarity of their structure. Changes in them from lust, hunger, and danger. All warm-blooded animals derived from one living filament. Cold-blooded animals, insects, worms, vegetables, derived also from one living filament. Male animals have teats. Male pigeon gives milk. The world itself generated. The cause of causes. A state of probation and responsibility._ V. 1. _Efficient cause of the colours of birds eggs, and of hair and feathers, which become white in snowy countries. Imagination of the female colours the egg. Ideas or motions of the retina imitated by the extremities of the nerves of touch, or rete mucosum._ 2. _Nutriment supplied by the female of three kinds. Her imagination can only affect the first kind. Mules how produced, and mulattoes. Organs of reproduction why deficient in mules. Eggs with double yolks._ VI. 1. _Various secretions produced by the extremities of the vessels, as in the glands. Contagious matter. Many glands affected by pleasurable ideas, as those which secrete the semen._ 2. _Snails and worms are hermaphrodite, yet cannot impregnate themselves. Final cause of this._ 3. _The imagination of the male forms the sex. Ideas, or motions of the nerves of vision or of touch, are imitated by the ultimate extremities of the glands of the testes, which mark the sex. This effect of the imagination belongs only to the male. The sex of the embryon is not owing to accident._ 4. _Causes of the changes in animals from imagination as in monsters. From the male. From the female._ 5. _Miscarriages from fear._ 6. _Power of the imagination of the male over the colour, form, and sex of the progeny. An instance of._ 7. _Act of generation accompanied with ideas of the male or female form. Art of begetting beautiful children of either sex._ VII. _Recapitulation._ VIII. _Conclusion. Of cause and effect. The atomic philosophy leads to a first cause._ I. The ingenious Dr. Hartley in his work on man, and some other philosophers, have been of opinion, that our immortal part acquires during this life certain habits of action or of sentiment, which become for ever indissoluble, continuing after death in a future state of existence; and add, that if these habits are of the malevolent kind, they must render the possessor miserable even in heaven. I would apply this ingenious idea to the generation or production of the embryon, or new animal, which partakes so much of the form and propensities of the parent. Owing to the imperfection of language the offspring is termed a _new_ animal, but is in truth a branch or elongation of the parent; since a part of the embryon-animal is, or was, a part of the parent; and therefore in strict language it cannot be said to be entirely _new_ at the time of its production; and therefore it may retain some of the habits of the parent-system. At the earliest period of its existence the embryon, as secreted from the blood of the male, would seem to consist of a living filament with certain capabilities of irritation, sensation, volition, and association; and also with some acquired habits or propensities peculiar to the parent: the former of these are in common with other animals; the latter seem to distinguish or produce the kind of animal, whether man or quadruped, with the similarity of feature or form to the parent. It is difficult to be conceived, that a living entity can be separated or produced from the blood by the action of a gland; and which shall afterwards become an animal similar to that in whose vessels it is formed; even though we should suppose with some modern theorists, that the blood is alive; yet every other hypothesis concerning generation rests on principles still more difficult to our comprehension. At the time of procreation this speck of entity is received into an appropriated nidus, in which it must acquire two circumstances necessary to its life and growth; one of these is food or sustenance, which is to be received by the absorbent mouths of its vessels; and the other is that part of atmospherical air, or of water, which by the new chemistry is termed oxygene, and which affects the blood by passing through the coats of the vessels which contain it. The fluid surrounding the embryon in its new habitation, which is called liquor amnii, supplies it with nourishment; and as some air cannot but be introduced into the uterus along with a new embryon, it would seem that this same fluid would for a short time, suppose for a few hours, supply likewise a sufficient quantity of the oxygene for its immediate existence. On this account the vegetable impregnation of aquatic plants is performed in the air; and it is probable that the honey-cup or nectary of vegetables requires to be open to the air, that the anthers and stigmas of the flower may have food of a more oxygenated kind than the common vegetable sap-juice. On the introduction of this primordium of entity into the uterus the irritation of the liquor amnii, which surrounds it, excites the absorbent mouths of the new vessels into action; they drink up a part of it, and a pleasurable sensation accompanies this new action; at the same time the chemical affinity of the oxygene acts through the vessels of the rubescent blood; and a previous want, or disagreeable sensation, is relieved by this process. As the want of this oxygenation of the blood is perpetual, (as appears from the incessant necessity of breathing by lungs or gills,) the vessels become extended by the efforts of pain or desire to seek this necessary object of oxygenation, and to remove the disagreeable sensation, which that want occasions. At the same time new particles of matter are absorbed, or applied to these extended vessels, and they become permanently elongated, as the fluid in contact with them soon loses the oxygenous part, which it at first possessed, which was owing to the introduction of air along with the embryon. These new blood-vessels approach the sides of the uterus, and penetrate with their fine terminations into the vessels of the mother; or adhere to them, acquiring oxygene through their coats from the passing currents of the arterial blood of the mother. See Sect. XXXVIII. 2. This attachment of the placental vessels to the internal side of the uterus by their own proper efforts appears further illustrated by the many instances of extra-uterine fetuses, which have thus attached or inserted their vessels into the peritoneum; or on the viscera, exactly in the same manner as they naturally insert or attach them to the uterus. The absorbent vessels of the embryon continue to drink up nourishment from the fluid in which they swim, or liquor amnii; and which at first needs no previous digestive preparation; but which, when the whole apparatus of digestion becomes complete, is swallowed by the mouth into the stomach, and being mixed with saliva, gastric juice, bile, pancreatic juice, and mucus of the intestines, becomes digested, and leaves a recrement, which produces the first feces of the infant, called meconium. The liquor amnii is secreted into the uterus, as the fetus requires it, and may probably be produced by the irritation of the fetus as an extraneous body; since a similar fluid is acquired from the peritoneum in cases of extra-uterine gestation. The young caterpillars of the gadfly placed in the skins of cows, and the young of the ichneumon-fly placed in the backs of the caterpillars on cabbages, seem to produce their nourishment by their irritating the sides of their nidus. A vegetable secretion and concretion is thus produced on oak-leaves by the gall-insect, and by the cynips in the bedeguar of the rose; and by the young grasshopper on many plants, by which the animal surrounds itself with froth. But in no circumstance is extra-uterine gestation so exactly resembled as by the eggs of a fly, which are deposited in the frontal sinus of sheep and calves. These eggs float in some ounces of fluid collected in a thin pellicle or hydatide. This bag of fluid compresses the optic nerve on one side, by which the vision being less distinct in that eye, the animal turns in perpetual circles towards the side affected, in order to get a more accurate view of objects; for the same reason as in squinting the affected eye is turned away from the object contemplated. Sheep in the warm months keep their noses close to the ground to prevent this fly from so readily getting into their nostrils. The liquor amnii is secreted into the womb as it is required, not only in respect to quantity, but, as the digestive powers of the fetus become formed, this fluid becomes of a different consistence and quality, till it is exchanged for milk after nativity. Haller. Physiol. V. 1. In the egg the white part, which is analogous to the liquor amnii of quadrupeds, consists of two distinct parts; one of which is more viscid, and probably more difficult of digestion, and more nutritive than the other; and this latter is used in the last week of incubation. The yolk of the egg is a still stronger or more nutritive fluid, which is drawn up into the bowels of the chick just at its exclusion from the shell, and serves it for nourishment for a day or two, till it is able to digest, and has learnt to choose the harder seeds or grains, which are to afford it sustenance. Nothing analogous to this yolk is found in the fetus of lactiferous animals, as the milk is another nutritive fluid ready prepared for the young progeny. The yolk therefore is not necessary to the spawn of fish, the eggs of insects, or for the seeds of vegetables; as their embryons have probably their food presented to them as soon as they are excluded from their shells, or have extended their roots. Whence it happens that some insects produce a living progeny in the spring and summer, and eggs in the autumn; and some vegetables have living roots or buds produced in the place of seeds, as the polygonum viviparum, and magical onions. See Botanic Garden, p. 11. art. anthoxanthum. There seems however to be a reservoir of nutriment prepared for some seeds besides their cotyledons or seed-leaves, which may be supposed in some measure analogous to the yolk of the egg. Such are the saccharine juices of apples, grapes and other fruits, which supply nutrition to the seeds after they fall on the ground. And such is the milky juice in the centre of the cocoa-nut, and part of the kernel of it; the same I suppose of all other monocotyledon seeds, as of the palms, grasses, and lilies. II. 1. The process of generation is still involved in impenetrable obscurity, conjectures may nevertheless be formed concerning some of its circumstances. First, the eggs of fish and frogs are impregnated, after they leave the body of the female; because they are deposited in a fluid, and are not therefore covered with a hard shell. It is however remarkable, that neither frogs nor fish will part with their spawn without the presence of the male; on which account female carp and gold-fish in small ponds, where there are no males, frequently die from the distention of their growing spawn. 2. The eggs of fowls, which are laid without being impregnated, are seen to contain only the yolk and white, which are evidently the food or sustenance for the future chick. 3. As the cicatricula of these eggs is given by the cock, and is evidently the rudiment of the new animal; we may conclude, that the embryon is produced by the male, and the proper food and nidus by the female. For if the female be supposed to form an equal part of the embryon, why should she form the whole of the apparatus for nutriment and for oxygenation? the male in many animals is larger, stronger, and digests more food than the female, and therefore should contribute as much or more towards the reproduction of the species; but if he contributes only half the embryon and none of the apparatus for sustenance and oxygenation, the division is unequal; the strength of the male, and his consumption of food are too great for the effect, compared with that of the female, which is contrary to the usual course of nature. In objection to this theory of generation it may be said, if the animalcula in femine, as seen by the microscope, be all of them rudiments of homunculi, when but one of them can find a nidus, what a waste nature has made of her productions? I do not assert that these moving particles, visible by the microscope, are homunciones; perhaps they may be the creatures of stagnation or putridity, or perhaps no creatures at all; but if they are supposed to be rudiments of homunculi, or embryons, such a profusion of them corresponds with the general efforts of nature to provide for the continuance of her species of animals. Every individual tree produces innumerable seeds, and every individual fish innumerable spawn, in such inconceivable abundance as would in a short space of time crowd the earth and ocean with inhabitants; and these are much more perfect animals than the animalcula in femine can be supposed to be, and perish in uncounted millions. This argument only shews, that the productions of nature are governed by general laws; and that by a wise superfluity of provision she has ensured their continuance. 2. That the embryon is secreted or produced by the male, and not by the conjunction of fluids from both male and female, appears from the analogy of vegetable seeds. In the large flowers, as the tulip, there is no similarity of apparatus between the anthers and the stigma: the seed is produced according to the observations of Spallanzani long before the flowers open, and in consequence long before it can be impregnated, like the egg in the pullet. And after the prolific dust is shed on the stigma, the seed becomes coagulated in one point first, like the cicatricula of the impregnated egg. See Botanic Garden, Part I. additional note 38. Now in these simple products of nature, if the female contributed to produce the new embryon equally with the male, there would probably have been some visible similarity of parts for this purpose, besides those necessary for the nidus and sustenance of the new progeny. Besides in many flowers the males are more numerous than the females, or than the separate uterine cells in their germs, which would shew, that the office of the male was at least as important as that of the female; whereas if the female, besides producing the egg or seed, was to produce an equal part of the embryon, the office of reproduction would be unequally divided between them. Add to this, that in the most simple kind of vegetable reproduction, I mean the buds of trees, which are their viviparous offspring, the leaf is evidently the parent of the bud, which rises in its bosom, according to the observation of Linnaeus. This leaf consists of absorbent vessels, and pulmonary ones, to obtain its nutriment, and to impregnate it with oxygene. This simple piece of living organization is also furnished with a power of reproduction; and as the new offspring is thus supported adhering to its father, it needs no mother to supply it with a nidus, and nutriment, and oxygenation; and hence no female leaf has existence. I conceive that the vessels between the bud and the leaf communicate or inosculate; and that the bud is thus served with vegetable blood, that is, with both nutriment and oxygenation, till the death of the parent-leaf in autumn. And in this respect it differs from the fetus of viviparous animals. Secondly, that then the bark-vessels belonging to the dead-leaf, and in which I suppose a kind of manna to have been deposited, become now the placental vessels, if they may be so called, of the new bud. From the vernal sap thus produced of one sugar-maple-tree in New-York and in Pennsylvania, five or six pounds of good sugar may be made annually without destroying the tree. Account of maple-sugar by B. Rushes. London, Phillips. (See Botanic Garden, Part I. additional note on vegetable placentation.) These vessels, when the warmth of the vernal sun hatches the young bud, serve it with a saccharine nutriment, till it acquires leaves of its own, and shoots a new system of absorbents down the bark and root of the tree, just as the farinaceous or oily matter in seeds, and the saccharine matter in fruits, serve their embryons with nutriment, till they acquire leaves and roots. This analogy is as forceable in so obscure a subject, as it is curious, and may in large buds, as of the horse-chesnut, be almost seen by the naked eye; if with a penknife the remaining rudiment of the last year's leaf, and of the new bud in its bosom, be cut away slice by slice. The seven ribs of the last year's leaf will be seen to have arisen from the pith in seven distinct points making a curve; and the new bud to have been produced in their centre, and to have pierced the alburnum and cortex, and grown without the assistance of a mother. A similar process may be seen on dissecting a tulip-root in winter; the leaves, which inclosed the last year's flower-stalk, were not necessary for the flower; but each of these was the father of a new bud, which may be now found at its base; and which, as it adheres to the parent, required no mother. This paternal offspring of vegetables, I mean their buds and bulbs, is attended with a very curious circumstance; and that is, that they exactly resemble their parents, as is observable in grafting fruit-trees, and in propagating flower-roots; whereas the seminal offspring of plants, being supplied with nutriment by the mother, is liable to perpetual variation. Thus also in the vegetable class dioicia, where the male flowers are produced on one tree, and the female ones on another; the buds of the male trees uniformly produce either male flowers, or other buds similar to themselves; and the buds of the female trees produce either female flowers, or other buds similar to themselves; whereas the seeds of these trees produce either male or female plants. From this analogy of the production of vegetable buds without a mother, I contend that the mother does not contribute to the formation of the living ens in animal generation, but is necessary only for supplying its nutriment and oxygenation. There is another vegetable fact published by M. Koelreuter, which he calls "a complete metamorphosis of one natural species of plants into another," which shews, that in seeds as well as in buds, the embryon proceeds from the male parent, though the form of the subsequent mature plant is in part dependant on the female. M. Koelreuter impregnated a stigma of the nicotiana rustica with the farina of the nicotiana paniculata, and obtained prolific seeds from it. With the plants which sprung from these seeds, he repeated the experiment, impregnating them with the farina of the nicotiana paniculata. As the mule plants which he thus produced were prolific, he continued to impregnate them for many generations with the farina of the nicotiana paniculata, and they became more and more like the male parent, till he at length obtained six plants in every respect perfectly similar to the nicotiana paniculata; and in no respect resembling their female parent the nicotiana rustica. _Blumenbach_ on Generation. 3. It is probable that the insects, which are said to require but one impregnation for six generations, as the aphis (see Amenit. Academ.) produce their progeny in the manner above described, that is, without a mother, and not without a father; and thus experience a lucina sine concubitu. Those who have attended to the habits of the polypus, which is found in the stagnant water of our ditches in July, affirm, that the young ones branch out from the side of the parent like the buds of trees, and after a time separate themselves from them. This is so analogous to the manner in which the buds of trees appear to be produced, that these polypi may be considered as all male animals, producing embryons, which require no mother to supply them with a nidus, or with nutriment, and oxygenation. This lateral or lineal generation of plants, not only obtains in the buds of trees, which continue to adhere to them, but is beautifully seen in the wires of knot-grass, polygonum aviculare, and in those of strawberries, fragaria vesca. In these an elongated creeping bud is protruded, and, where it touches the ground, takes root, and produces a new plant derived from its father, from which it acquires both nutriment and oxygenation; and in consequence needs no maternal apparatus for these purposes. In viviparous flowers, as those of allium magicum, and polygonum viviparum, the anthers and the stigmas become effete and perish; and the lateral or paternal offspring succeeds instead of seeds, which adhere till they are sufficiently mature, and then fall upon the ground, and take root like other bulbs. The lateral production of plants by wires, while each new plant is thus chained to its parent, and continues to put forth another and another, as the wire creeps onward on the ground, is exactly resembled by the tape-worm, or tænia, so often found in the bowels, stretching itself in a chain quite from the stomach to the rectum. Linnæus asserts, "that it grows old at one extremity, while it continues to generate young ones at the other, proceeding ad infinitum, like a root of grass. The separate joints are called gourd-worms, and propagate new joints like the parent without end, each joint being furnished with its proper mouth, and organs of digestion." Systema naturæ. Vermes tenia. In this animal there evidently appears a power of reproduction without any maternal apparatus for the purpose of supplying nutriment and oxygenation to the embryon, as it remains attached to its father till its maturity. The volvox globator, which is a transparent animal, is said by Linnæus to bear within it sons and grand-sons to the fifth generation. These are probably living fetuses, produced by the father, of different degrees of maturity, to be detruded at different periods of time, like the unimpregnated eggs of various sizes, which are found in poultry; and as they are produced without any known copulation, contribute to evince, that the living embryon in other orders of animals is formed by the male-parent, and not by the mother, as one parent has the power to produce it. This idea of the reproduction of animals from a single living filament of their fathers, appears to have been shadowed or allegorized in the curious account in sacred writ of the formation of Eve from a rib of Adam. From all these analogies I conclude, that the embryon is produced solely by the male, and that the female supplies it with a proper nidus, with sustenance, and with oxygenation; and that the idea of the semen of the male constituting only a stimulus to the egg of the female, exciting it into life, (as held by some philosophers) has no support from experiment or analogy. III. 1. Many ingenious philosophers have found so great difficulty in conceiving the manner of the reproduction of animals, that they have supposed all the numerous progeny, to have existed in miniature in the animal originally created; and that these infinitely minute forms are only evolved or distended, as the embryon increases in the womb. This idea, besides its being unsupported by any analogy we are acquainted with, ascribes a greater tenuity to organized matter, than we can readily admit; as these included embryons are supposed each of them to consist of the various and complicate parts of animal bodies: they must possess a much greater degree of minuteness, than that which was ascribed to the devils that tempted St. Anthony; of whom 20,000 were said to have been able to dance a saraband on the point of the finest needle without incommoding each other. 2. Others have supposed, that all the parts of the embryon are formed in the male, previous to its being deposited in the egg or uterus; and that it is then only to have its parts evolved or distended as mentioned above; but this is only to get rid of one difficulty by proposing another equally incomprehensible: they found it difficult to conceive, how the embryon could be formed in the uterus or egg, and therefore wished it to be formed before it came thither. In answer to both these doctrines it may be observed, 1st, that some animals, as the crab-fish, can reproduce a whole limb, as a leg which has been broken off; others, as worms and snails, can reproduce a head, or a tail, when either of them has been cut away; and that hence in these animals at least a part can be formed anew, which cannot be supposed to have existed previously in miniature. Secondly, there are new parts or new vessels produced in many diseases, as on the cornea of the eye in ophthalmy, in wens and cancers, which cannot be supposed to have had a prototype or original miniature in the embryon. Thirdly, how could mule-animals be produced, which partake of the forms of both the parents, if the original embryon was a miniature existing in the semen of the male parent? if an embryon of the male ass was only expanded, no resemblance to the mare could exist in the mule. This mistaken idea of the extension of parts seems to have had its rise from the mature man resembling the general form of the fetus; and from thence it was believed, that the parts of the fetus were distended into the man; whereas they have increased 100 times in weight, as well as 100 times in size; now no one will call the additional 99 parts a distention of the original one part in respect to weight. Thus the uterus during pregnancy is greatly enlarged in thickness and solidity as well as in capacity, and hence must have acquired this additional size by accretion of new parts, not by an extension of the old ones; the familiar act of blowing up the bladder of an animal recently slaughtered has led our imaginations to apply this idea of distention to the increase of size from natural growth; which however must be owing to the apposition of new parts; as it is evinced from the increase of weight along with the increase of dimension; and is even visible to our eyes in the elongation of our hair from the colour of its ends; or when it has been dyed on the head; and in the growth of our nails from the specks sometimes observable on them; and in the increase of the white crescent at their roots, and in the growth of new flesh in wounds, which consists of new nerves as well as of new blood-vessels. 3. Lastly, Mr. Buffon has with great ingenuity imagined the existence of certain organic particles, which are supposed to be partly alive, and partly mechanic springs. The latter of these were discovered by Mr. Needham in the milt or male organ of a species of cuttle fish, called calmar; the former, or living animalcula, are found in both male and female secretions, in the infusions of seeds, as of pepper, in the jelly of roasted veal, and in all other animal and vegetable substances. These organic particles he supposes to exist in the spermatic fluids of both sexes, and that they are derived thither from every part of the body, and must therefore resemble, as he supposes, the parts from whence they are derived. These organic particles he believes to be in constant activity, till they become mixed in the womb, and then they instantly join and produce an embryon or fetus similar to the two parents. Many objections might be adduced to this fanciful theory, I shall only mention two. First, that it is analogous to no known animal laws. And secondly, that as these fluids, replete with organic particles derived both from the male and female organs, are supposed to be similar; there is no reason why the mother should not produce a female embryon without the assistance of the male, and realize the lucina sine concubitu. IV. 1. I conceive the primordium, or rudiment of the embryon, as secreted from the blood of the parent, to consist of a simple living filament as a muscular fibre; which I suppose to be an extremity of a nerve of loco-motion, as a fibre of the retina is an extremity of a nerve of sensation; as for instance one of the fibrils, which compose the mouth of an absorbent vessel; I suppose this living filament, of whatever form it may be, whether sphere, cube, or cylinder, to be endued with the capability of being excited into action by certain kinds of stimulus. By the stimulus of the surrounding fluid, in which it is received from the male, it may bend into a ring; and thus form the beginning of a tube. Such moving filaments, and such rings, are described by those, who have attended to microscopic animalcula. This living ring may now embrace or absorb a nutritive particle of the fluid, in which it swims; and by drawing it into its pores, or joining it by compression to its extremities, may increase its own length or crassitude; and by degrees the living ring may become a living tube. 2. With this new organization, or accretion of parts, new kinds of irritability may commence; for so long as there was but one living organ, it could only be supposed to possess irritability; since sensibility may be conceived to be an extension of the effect of irritability over the rest of the system. These new kinds of irritability and of sensibility in consequence of new organization, appear from variety of facts in the more mature animal; thus the formation of the testes, and consequent secretion of the semen, occasion the passion of lust; the lungs must be previously formed before their exertions to obtain fresh air can exist; the throat or oesophagus must be formed previous to the sensation or appetites of hunger and thirst; one of which seems to reside at the upper end, and the other at the lower end of that canal. Thus also the glans penis, when it is distended with blood, acquires a new sensibility, and a new appetency. The same occurs to the nipples of the breasts of female animals, when they are distended with blood, they acquire the new appetency of giving milk. So inflamed tendons and membranes, and even bones, acquire new sensations; and the parts of mutilated animals, as of wounded snails, and polypi, and crabs, are reproduced; and at the same time acquire sensations adapted to their situations. Thus when the head of a snail is reproduced after decollation with a sharp rasor, those curious telescopic eyes are also reproduced, and acquire their sensibility to light, as well as their adapted muscles for retraction on the approach of injury. With every new change, therefore, of organic form, or addition of organic parts, I suppose a new kind of irritability or of sensibility to be produced; such varieties of irritability or of sensibility exist in our adult state in the glands; every one of which is furnished with an irritability, or a taste, or appetency, and a consequent mode of action peculiar to itself. In this manner I conceive the vessels of the jaws to produce those of the teeth, those of the fingers to produce the nails, those of the skin to produce the hair; in the same manner as afterwards about the age of puberty the beard and other great changes in the form of the body, and disposition of the mind, are produced in consequence of the new secretion of semen; for if the animal is deprived of this secretion those changes do not take place. These changes I conceive to be formed not by elongation or distention of primeval stamina, but by apposition of parts; as the mature crab-fish, when deprived of a limb, in a certain space of time has power to regenerate it; and the tadpole puts forth its feet long after its exclusion from the spawn; and the caterpillar in changing into a butterfly acquires a new form, with new powers, new sensations, and new desires. The natural history of butterflies, and moths, and beetles, and gnats, is full of curiosity; some of them pass many months, and others even years, in their caterpillar or grub state; they then rest many weeks without food, suspended in the air, buried in the earth, or submersed in water; and change themselves during this time into an animal apparently of a different nature; the stomachs of some of them, which before digested vegetable leaves or roots, now only digest honey; they have acquired wings for the purpose of seeking this new food, and a long proboscis to collect it from flowers, and I suppose a sense of smell to detect the secret places in flowers, where it is formed. The moths, which fly by night, have a much longer proboscis rolled up under their chins like a watch spring; which they extend to collect the honey from flowers in their sleeping state; when they are closed, and the nectaries in consequence more difficult to be plundered. The beetle kind are furnished with an external covering of a hard material to their wings, that they may occasionally again make holes in the earth, in which they passed the former state of their existence. But what most of all distinguishes these new animals is, that they are new furnished with the powers of reproduction; and that they now differ from each other in sex, which does not appear in their caterpillar or grub state. In some of them the change from a caterpillar into a butterfly or moth seems to be accomplished for the sole purpose of their propagation; since they immediately die after this is finished, and take no food in the interim, as the silk-worm in this climate; though it is possible, it might take honey as food, if it was presented to it. For in general it would seem, that food of a more stimulating kind, the honey of vegetables instead of their leaves, was necessary for the purpose of the seminal reproduction of these animals, exactly similar to what happens in vegetables; in these the juices of the earth are sufficient for their purpose of reproduction by buds or bulbs; in which the new plant seems to be formed by irritative motions, like the growth of their other parts, as their leaves or roots; but for the purpose of seminal or amatorial reproduction, where sensation is required, a more stimulating food becomes necessary for the anther, and stigma; and this food is honey; as explained in Sect. XIII. on Vegetable Animation. The gnat and the tadpole resemble each other in their change from natant animals with gills into aerial animals with lungs; and in their change of the element in which they live; and probably of the food, with which they are supported; and lastly, with their acquiring in their new state the difference of sex, and the organs of seminal or amatorial reproduction. While the polypus, who is their companion in their former state of life, not being allowed to change his form and element, can only propagate like vegetable buds by the same kind of irritative motions, which produces the growth of his own body, without the seminal or amatorial propagation, which requires sensation; and which in gnats and tadpoles seems to require a change both of food and of respiration. From hence I conclude, that with the acquisition of new parts, new sensations, and new desires, as well as new powers, are produced; and this by accretion to the old ones, and not by distention of them. And finally, that the most essential parts of the system, as the brain for the purpose of distributing the power of life, and the placenta for the purpose of oxygenating the blood, and the additional absorbent vessels for the purpose of acquiring aliment, are first formed by the irritations above mentioned, and by the pleasurable sensations attending those irritations, and by the exertions in consequence of painful sensations, similar to those of hunger and suffocation. After these an apparatus of limbs for future uses, or for the purpose of moving the body in its present natant state, and of lungs for future respiration, and of testes for future reproduction, are formed by the irritations and sensations, and consequent exertions of the parts previously existing, and to which the new parts are to be attached. 3. In confirmation of these ideas it may be observed, that all the parts of the body endeavour to grow, or to make additional parts to themselves throughout our lives; but are restrained by the parts immediately containing them; thus, if the skin be taken away, the fleshy parts beneath soon shoot out new granulations, called by the vulgar proud flesh. If the periosteum be removed, a similar growth commences from the bone. Now in the case of the imperfect embryon, the containing or confining parts are not yet supposed to be formed, and hence there is nothing to restrain its growth. 4. By the parts of the embryon being thus produced by new apportions, many phenomena both of animal and vegetable productions receive an easier explanation; such as that many fetuses are deficient at the extremities, as in a finger or a toe, or in the end of the tongue, or in what is called a hare-lip with deficiency of the palate. For if there should be a deficiency in the quantity of the first nutritive particles laid up in the egg for the reception of the first living filament, the extreme parts, as being last formed, must shew this deficiency by their being imperfect. This idea of the growth of the embryon accords also with the production of some monstrous births, which consist of a duplicature of the limbs, as chickens with four legs; which could not occur, if the fetus was formed by the distention of an original stamen, or miniature. For if there should be a superfluity of the first nutritive particles laid up in the egg for the first living filament; it is easy to conceive, that a duplicature of some parts may be formed. And that such superfluous nourishment sometimes exists, is evinced by the double yolks in some eggs, which I suppose were thus formed previous to their impregnation by the exuberant nutriment of the hen. This idea is confirmed by the analogy of the monsters in the vegetable world also; in which a duplicate or triplicate production of various parts of the flower is observable, as a triple nectary in some columbines, and a triple petal in some primroses; and which are supposed to be produced by abundant nourishment. 5. If the embryon be received into a fluid, whose stimulus is different in some degree from the natural, as in the production of mule-animals, the new irritabilities or sensibilities acquired by the increasing or growing organized parts may differ, and thence produce parts not similar to the father, but of a kind belonging in part to the mother; and thus, though the original stamen or living ens was derived totally from the father, yet new irritabilities or sensibilities being excited, a change of form corresponding with them will be produced. Nor could the production of mules exist, if the stamen or miniature of all the parts of the embryon is previously formed in the male semen, and is only distended by nourishment in the female uterus. Whereas this difficulty ceases, if the embryon be supposed to consist of a living filament, which acquires or makes new parts with new irritabilities, as it advances in its growth. The form, solidity, and colour, of the particles of nutriment laid up for the reception of the first living filament, as well as their peculiar kind of stimulus, may contribute to produce a difference in the form, solidity, and colour of the fetus, so as to resemble the mother, as it advances in life. This also may especially happen during the first state of the existence of the embryon, before it has acquired organs, which can change these first nutritive particles, as explained in No. 5. 2. of this Section. And as these nutritive particles are supposed to be similar to those, which are formed for her own nutrition, it follows that the fetus should so far resemble the mother. This explains, why hereditary diseases may be derived either from the male or female parent, as well as the peculiar form of either of their bodies. Some of these hereditary diseases are simply owing to a deficient activity of a part of the system, as of the absorbent vessels, which open into the cells or cavities of the body, and thus occasion dropsies. Others are at the same time owing to an increase of sensation, as in scrophula and consumption; in these the obstruction of the fluids is first caused by the inirritability of the vessels, and the inflammation and ulcers which succeed, are caused by the consequent increase of sensation in the obstructed part. Other hereditary diseases, as the epilepsy, and other convulsions, consist in too great voluntary exertions in consequence of disagreeable sensation in some particular diseased part. Now as the pains, which occasion these convulsions, are owing to defect of the action of the diseased part, as shewn in Sect. XXXIV. it is plain, that all these hereditary diseases may have their origin either from defective irritability derived from the father, or from deficiency of the stimulus of the nutriment derived from the mother. In either case the effect would be similar; as a scrophulous race is frequently produced among the poor from the deficient stimulus of bad diet, or of hunger; and among the rich, by a deficient irritability from their having been long accustomed to too great stimulus, as of vinous spirit. 6. From this account of reproduction it appears, that all animals have a similar origin, viz. from a single living filament; and that the difference of their forms and qualities has arisen only from the different irritabilities and sensibilities, or voluntarities, or associabilities, of this original living filament; and perhaps in some degree from the different forms of the particles of the fluids, by which it has been at first stimulated into activity. And that from hence, as Linnæus has conjectured in respect to the vegetable world, it is not impossible, but the great variety of species of animals, which now tenant the earth, may have had their origin from the mixture of a few natural orders. And that those animal and vegetable mules, which could continue their species, have done so, and constitute the numerous families of animals and vegetables which now exist; and that those mules, which were produced with imperfect organs of generation, perished without reproduction, according to the observation of Aristotle; and are the animals, which we now call mules. See Botanic Garden, Part II. Note on Dianthus. Such a promiscuous intercourse of animals is said to exist at this day in New South Wales by Captain Hunter. And that not only amongst the quadrupeds and birds of different kinds, but even amongst the fish, and, as he believes, amongst the vegetables. He speaks of an animal between the opossum and the kangaroo, from the size of a sheep to that of a rat. Many fish seemed to partake of the shark; some with a shark's head and shoulders, and the hind part of a shark; others with a shark's head and the body of a mullet; and some with a shark's head and the flat body of a sting-ray. Many birds partake of the parrot; some have the head, neck, and bill of a parrot, with long straight feet and legs; others with legs and feet of a parrot, with head and neck of a sea gull. Voyage to South Wales by Captain John Hunter, p. 68. 7. All animals therefore, I contend, have a similar cause of their organization, originating from a single living filament, endued indeed with different kinds of irritabilities and sensibilities, or of animal appetencies; which exist in every gland, and in every moving organ of the body, and are as essential to living organization as chemical affinities are to certain combinations of inanimate matter. If I might be indulged to make a simile in a philosophical work, I should say, that the animal appetencies are not only perhaps less numerous originally than the chemical affinities; but that like these latter, they change with every new combination; thus vital air and azote, when combined, produce nitrous acid; which now acquires the property of dissolving silver; so with every new additional part to the embryon, as of the throat or lungs, I suppose a new animal appetency to be produced. In this early formation of the embryon from the irritabilities, sensibilities, and associabilities, and consequent appetencies, the faculty of volition can scarcely be supposed to have had its birth. For about what can the fetus deliberate, when it has no choice of objects? But in the more advanced state of the fetus, it evidently possesses volition; as it frequently changes its attitude, though it seems to sleep the greatest part of its time; and afterwards the power of volition contributes to change or alter many parts of the body during its growth to manhood, by our early modes of exertion in the various departments of life. All these faculties then constitute the vis fabricatrix, and the vis conservatrix, as well as the vis medicatrix of nature, so much spoken of, but so little understood by philosophers. 8. When we revolve in our minds, first, the great changes, which we see naturally produced in animals after their nativity, as in the production of the butterfly with painted wings from the crawling caterpillar; or of the respiring frog from the subnatant tadpole; from the feminine boy to the bearded man, and from the infant girl to the lactescent woman; both which changes may be prevented by certain mutilations of the glands necessary to reproduction. Secondly, when we think over the great changes introduced into various animals by artificial or accidental cultivation, as in horses, which we have exercised for the different purposes of strength or swiftness, in carrying burthens or in running races; or in dogs, which have been cultivated for strength and courage, as the bull-dog; or for acuteness of his sense or smell, as the hound and spaniel; or for the swiftness of his foot, as the greyhound; or for his swimming in the water, or for drawing snow-sledges, as the rough-haired dogs of the north; or lastly, as a play-dog for children, as the lap-dog; with the changes of the forms of the cattle, which have been domesticated from the greatest antiquity, as camels, and sheep; which have undergone so total a transformation, that we are now ignorant from what species of wild animals they had their origin. Add to these the great changes of shape and colour, which we daily see produced in smaller animals from our domestication of them, as rabbits, or pigeons; or from the difference of climates and even of seasons; thus the sheep of warm climates are covered with hair instead of wool; and the hares and partridges of the latitudes, which are long buried in snow, become white during the winter months; add to these the various changes produced in the forms of mankind, by their early modes of exertion; or by the diseases occasioned by their habits of life; both of which became hereditary, and that through many generations. Those who labour at the anvil, the oar, or the loom, as well as those who carry sedan-chairs, or who have been educated to dance upon the rope, are distinguishable by the shape of their limbs; and the diseases occasioned by intoxication deform the countenance with leprous eruptions, or the body with tumid viscera, or the joints with knots and distortions. Thirdly, when we enumerate the great changes produced in the species of animals before their nativity; these are such as resemble the form or colour of their parents, which have been altered by the cultivation or accidents above related, and are thus continued to their posterity. Or they are changes produced by the mixture of species as in mules; or changes produced probably by the exuberance of nourishment supplied to the fetus, as in monstrous births with additional limbs; many of these enormities of shape are propagated, and continued as a variety at least, if not as a new species of animal. I have seen a breed of cats with an additional claw on every foot; of poultry also with an additional claw, and with wings to their feet; and of others without rumps. Mr. Buffon mentions a breed of dogs without tails, which are common at Rome and at Naples, which he supposes to have been produced by a custom long established of cutting their tails close off. There are many kinds of pigeons, admired for their peculiarities, which are monsters thus produced and propagated. And to these must be added, the changes produced by the imagination of the male parent, as will be treated of more at large in No. VI. of this Section. When we consider all these changes of animal form, and innumerable others, which may be collected from the books of natural history; we cannot but be convinced, that the fetus or embryon is formed by apposition of new parts, and not by the distention of a primordial nest of germs, included one within another, like the cups of a conjurer. Fourthly, when we revolve in our minds the great similarity of structure, which obtains in all the warm-blooded animals, as well quadrupeds, birds, and amphibious animals, as in mankind; from the mouse and bat to the elephant and whale; one is led to conclude, that they have alike been produced from a similar living filament. In some this filament in its advance to maturity has acquired hands and fingers, with a fine sense of touch, as in mankind. In others it has acquired claws or talons, as in tygers and eagles. In others, toes with an intervening web, or membrane, as in seals and geese. In others it has acquired cloven hoofs, as in cows and swine; and whole hoofs in others, as in the horse. While in the bird kind this original living filament has put forth wings instead of arms or legs, and feathers instead of hair. In some it has protruded horns on the forehead instead of teeth in the fore part of the upper jaw; in others tushes instead of horns; and in others beaks instead of either. And all this exactly as is daily seen in the transmutations of the tadpole, which acquires legs and lungs, when he wants them; and loses his tail, when it is no longer of service to him. Fifthly, from their first rudiment, or primordium, to the termination of their lives, all animals undergo perpetual transformations; which are in part produced by their own exertions in consequence of their desires and aversions, of their pleasures and their pains, or of irritations, or of associations; and many of these acquired forms or propensities are transmitted to their posterity. See Sect. XXXI. 1. As air and water are supplied to animals in sufficient profusion, the three great objects of desire, which have changed the forms of many animals by their exertions to gratify them, are those of lust, hunger, and security. A great want of one part of the animal world has consisted in the desire of the exclusive possession of the females; and these have acquired weapons to combat each other for this purpose, as the very thick, shield-like, horny skin on the shoulder of the boar is a defence only against animals of his own species, who strike obliquely upwards, nor are his tushes for other purposes, except to defend himself, as he is not naturally a carnivorous animal. So the horns of the stag are sharp to offend his adversary, but are branched for the purpose of parrying or receiving the thrusts of horns similar to his own, and have therefore been formed for the purpose of combating other stags for the exclusive possession of the females; who are observed, like the ladies in the times of chivalry, to attend the car of the victor. The birds, which do not carry food to their young, and do not therefore marry, are armed with spurs for the purpose of fighting for the exclusive possession of the females, as cocks and quails. It is certain that these weapons are not provided for their defence against other adversaries, because the females of these species are without this armour. The final cause of this contest amongst the males seems to be, that the strongest and most active animal should propagate the species, which should thence become improved. Another great want consists in the means of procuring food, which has diversified the forms of all species of animals. Thus the nose of the swine has become hard for the purpose of turning up the soil in search of insects and of roots. The trunk of the elephant is an elongation of the nose for the purpose of pulling down the branches of trees for his food, and for taking up water without bending his knees. Beasts of prey have acquired strong jaws or talons. Cattle have acquired a rough tongue and a rough palate to pull off the blades of grass, as cows and sheep. Some birds have acquired harder beaks to crack nuts, as the parrot. Others have acquired beaks adapted to break the harder seeds, as sparrows. Others for the softer seeds of flowers, or the buds of trees, as the finches. Other birds have acquired long beaks to penetrate the moister soils in search of insects or roots, as woodcocks; and others broad ones to filtrate the water of lakes, and to retain aquatic insects. All which seem to have been gradually produced during many generations by the perpetual endeavour of the creatures to supply the want of food, and to have been delivered to their posterity with constant improvement of them for the purposes required. The third great want amongst animals is that of security, which seems much to have diversified the forms of their bodies and the colour of them; these consist in the means of escaping other animals more powerful than themselves. Hence some animals have acquired wings instead of legs, as the smaller birds, for the purpose of escape. Others great length of fin, or of membrane, as the flying fish, and the bat. Others great swiftness of foot, as the hare. Others have acquired hard or armed shells, as the tortoise and the echinus marinus. Mr. Osbeck, a pupil of Linnæus, mentions the American frog fish, Lophius Histrio, which inhabits the large floating islands of sea-weed about the Cape of Good Hope, and has fulcra resembling leaves, that the fishes of prey may mistake it for the sea-weed, which it inhabits. Voyage to China, p. 113. The contrivances for the purposes of security extend even to vegetables, as is seen in the wonderful and various means of their concealing or defending their honey from insects, and their seeds from birds. On the other hand swiftness of wing has been acquired by hawks and swallows to pursue their prey; and a proboscis of admirable structure has been acquired by the bee, the moth, and the humming bird, for the purpose of plundering the nectaries of flowers. All which seem to have been formed by the original living filament, excited into action by the necessities of the creatures, which possess them, and on which their existence depends. From thus meditating on the great similarity of the structure of the warm-blooded animals, and at the same time of the great changes they undergo both before and after their nativity; and by considering in how minute a portion of time many of the changes of animals above described have been produced; would it be too bold to imagine, that in the great length of time, since the earth began to exist, perhaps millions of ages before the commencement of the history of mankind, would it be too bold to imagine, that all warm-blooded animals have arisen from one living filament, which THE GREAT FIRST CAUSE endued with animality, with the power of acquiring new parts, attended with new propensities, directed by irritations, sensations, volitions, and associations; and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end! Sixthly, The cold-blooded animals, as the fish-tribes, which are furnished with but one ventricle of the heart, and with gills instead of lungs, and with fins instead of feet or wings, bear a great similarity to each other; but they differ, nevertheless, so much in their general structure from the warm-blooded animals, that it may not seem probable at first view, that the same living filament could have given origin to this kingdom of animals, as to the former. Yet are there some creatures, which unite or partake of both these orders of animation, as the whales and seals; and more particularly the frog, who changes from an aquatic animal furnished with gills to an aerial one furnished with lungs. The numerous tribes of insects without wings, from the spider to the scorpion, from the flea to the lobster; or with wings, from the gnat and the ant to the wasp and the dragon-fly, differ so totally from each other, and from the red-blooded classes above described, both in the forms of their bodies, and their modes of life; besides the organ of sense, which they seem to possess in their antennæ or horns, to which it has been thought by some naturalists, that other creatures have nothing similar; that it can scarcely be supposed that this nation of animals could have been produced by the same kind of living filament, as the red-blooded classes above mentioned. And yet the changes which many of them undergo in their early state to that of their maturity, are as different, as one animal can be from another. As those of the gnat, which passes his early state in water, and then stretching out his new wings, and expanding his new lungs, rises in the air; as of the caterpillar, and bee-nymph, which feed on vegetable leaves or farina, and at length bursting from their self-formed graves, become beautiful winged inhabitants of the skies, journeying from flower to flower, and nourished by the ambrosial food of honey. There is still another class of animals, which are termed vermes by Linnæus, which are without feet, or brain, and are hermaphrodites, as worms, leeches, snails, shell-fish, coralline insects, and sponges; which possess the simplest structure of all animals, and appear totally different from those already described. The simplicity of their structure, however, can afford no argument against their having been produced from a living filament as above contended. Last of all the various tribes of vegetables are to be enumerated amongst the inferior orders of animals. Of these the anthers and stigmas have already been shewn to possess some organs of sense, to be nourished by honey, and to have the power of generation like insects, and have thence been announced amongst the animal kingdom in Sect. XIII. and to these must be added the buds and bulbs which constitute the viviparous offspring of vegetation. The former I suppose to be beholden to a single living filament for their seminal or amatorial procreation; and the latter to the same cause for their lateral or branching generation, which they possess in common with the polypus, tænia, and volvox; and the simplicity of which is an argument in favour of the similarity of its cause. Linnæus supposes, in the Introduction to his Natural Orders, that very few vegetables were at first created, and that their numbers were increased by their intermarriages, and adds, suadent hæc Creatoris leges a simplicibus ad composita. Many other changes seem to have arisen in them by their perpetual contest for light and air above ground, and for food or moisture beneath the soil. As noted in Botanic Garden, Part II. Note on Cuscuta. Other changes of vegetables from climate, or other causes, are remarked in the Note on Curcuma in the same work. From these one might be led to imagine, that each plant at first consisted of a single bulb or flower to each root, as the gentianella and daisy; and that in the contest for air and light new buds grew on the old decaying flower stem, shooting down their elongated roots to the ground, and that in process of ages tall trees were thus formed, and an individual bulb became a swarm of vegetables. Other plants, which in this contest for light and air were too slender to rise by their own strength, learned by degrees to adhere to their neighbours, either by putting forth roots like the ivy, or by tendrils like the vine, or by spiral contortions like the honeysuckle; or by growing upon them like the misleto, and taking nourishment from their barks; or by only lodging or adhering on them, and deriving nourishment from the air, as tillandsia. Shall we then say that the vegetable living filament was originally different from that of each tribe of animals above described? And that the productive living filament of each of those tribes was different originally from the other? Or, as the earth and ocean were probably peopled with vegetable productions long before the existence of animals; and many families of these animals long before other families of them, shall we conjecture that one and the same kind of living filaments is and has been the cause of all organic life? This idea of the gradual formation and improvement of the animal world accords with the observations of some modern philosophers, who have supposed that the continent of America has been raised out of the ocean at a later period of time than the other three quarters of the globe, which they deduce from the greater comparative heights of its mountains, and the consequent greater coldness of its respective climates, and from the less size and strength of its animals, as the tygers and allegators compared with those of Asia or Africa. And lastly, from the less progress in the improvements of the mind of its inhabitants in respect to voluntary exertions. This idea of the gradual formation and improvement of the animal world seems not to have been unknown to the ancient philosophers. Plato having probably observed the reciprocal generation of inferior animals, as snails and worms, was of opinion, that mankind with all other animals were originally hermaphrodites during the infancy of the world, and were in process of time separated into male and female. The breasts and teats of all male quadrupeds, to which no use can be now assigned, adds perhaps some shadow of probability to this opinion. Linnæus excepts the horse from the male quadrupeds, who have teats; which might have shewn the earlier origin of his exigence; but Mr. J. Hunter asserts, that he has discovered the vestiges of them on his sheath, and has at the same time enriched natural history with a very curious fact concerning the male pigeon; at the time of hatching the eggs both the male and female pigeon undergo a great change in their crops; which thicken and become corrugated, and secrete a kind of milky fluid, which coagulates, and with which alone they for a few days feed their young, and afterwards feed them with this coagulated fluid mixed with other food. How this resembles the breasts of female quadrupeds after the production of their young! and how extraordinary, that the male should at this time give milk as well as the female! See Botanic Garden, Part II. Note on Curcuma. The late Mr. David Hume, in his posthumous works, places the powers of generation much above those of our boasted reason; and adds, that reason can only make a machine, as a clock or a ship, but the power of generation makes the maker of the machine; and probably from having observed, that the greatest part of the earth has been formed out of organic recrements; as the immense beds of limestone, chalk, marble, from the shells of fish; and the extensive provinces of clay, sandstone, ironstone, coals, from decomposed vegetables; all which have been first produced by generation, or by the secretions of organic life; he concludes that the world itself might have been generated, rather than created; that is, it might have been gradually produced from very small beginnings, increasing by the activity of its inherent principles, rather than by a sudden evolution of the whole by the Almighty fire.--What a magnificent idea of the infinite power of THE GREAT ARCHITECT! THE CAUSE OF CAUSES! PARENT OF PARENTS! ENS ENTIUM! For if we may compare infinities, it would seem to require a greater infinity of power to cause the causes of effects, than to cause the effects themselves. This idea is analogous to the improving excellence observable in every part of the creation; such as in the progressive increase of the solid or habitable parts of the earth from water; and in the progressive increase of the wisdom and happiness of its inhabitants; and is consonant to the idea of our present situation being a state of probation, which by our exertions we may improve, and are consequently responsible for our actions. V. 1. The efficient cause of the various colours of the eggs of birds, and of the air and feathers of animals, is a subject so curious, that I shall beg to introduce it in this place. The colours of many animals seem adapted to their purposes of concealing themselves either to avoid danger, or to spring upon their prey. Thus the snake and wild cat, and leopard, are so coloured as to resemble dark leaves and their lighter interstices; birds resemble the colour of the brown ground, or the green hedges, which they frequent; and moths and butterflies are coloured like the flowers which they rob of their honey. Many instances are mentioned of this kind in Botanic Garden, p. 2. Note on Rubia. These colours have, however, in some instances another use, as the black diverging area from the eyes of the swan; which, as his eyes are placed less prominent than those of other birds, for the convenience of putting down his head under water, prevents the rays of light from being reflected into his eye, and thus dazzling his sight, both in air and beneath the water; which must have happened, if that surface had been white like the rest of his feathers. There is a still more wonderful thing concerning these colours adapted to the purpose of concealment; which is, that the eggs of birds are so coloured as to resemble the colour of the adjacent objects and their interfaces. The eggs of hedge-birds are greenish with dark spots; those of crows and magpies, which are seen from beneath through wicker nests, are white with dark spots; and those of larks and partridges are russet or brown, like their nests or situations. A thing still more astonishing is, that many animals in countries covered with snow become white in winter, and are said to change their colour again in the warmer months, as bears, hares, and partridges. Our domesticated animals lose their natural colours, and break into great variety, as horses, dogs, pigeons. The final cause of these colours is easily understood, as they serve some purposes of the animal, but the efficient cause would seem almost beyond conjecture. First, the choroid coat of the eye, on which the semitransparent retina is expanded, is of different colour in different animals; in those which feed on grass it is green; from hence there would appear some connexion between the colour of the choroid coat and of that constantly painted on the retina by the green grass. Now, when the ground becomes covered with snow, it would seem, that that action of the retina, which is called whiteness, being constantly excited in the eye, may be gradually imitated by the extremities of the nerves of touch, or rete mucosum of the skin. And if it be supposed, that the action of the retina in producing the perception of any colour consists in so disposing its own fibres or surface, as to reflect those coloured rays only, and transmit the others like soap-bubbles; then that part of the retina, which gives us the perception of snow, must at that time be white; and that which gives us the perception of grass, must be green. Then if by the laws of imitation, as explained in Section XII. 3. 3. and XXXIX. 6. the extremities of the nerves of touch in the rete mucosum be induced into similar action, the skin or feathers, or hair, may in like manner so dispose their extreme fibres, as to reflect white; for it is evident, that all these parts were originally obedient to irritative motions during their growth, and probably continue to be so; that those irritative motions are not liable in a healthy state to be succeeded by sensation; which however is no uncommon thing in their diseased state, or in their infant state, as in plica polonica, and in very young pen-feathers, which are still full of blood. It was shewn in Section XV. on the Production of Ideas, that the moving organ of sense in some circumstances resembled the object which produced that motion. Hence it may be conceived, that the rete mucosum, which is the extremity of the nerves of touch, may by imitating the motions of the retina become coloured. And thus, like the fable of the camelion, all animals may possess a tendency to be coloured somewhat like the colours they most frequently inspect, and finally, that colours may be thus given to the egg-shell by the imagination of the female parent; which shell is previously a mucous membrane, indued with irritability, without which it could not circulate its fluids, and increase in its bulk. Nor is this more wonderful than that a single idea of imagination mould in an instant colour the whole surface of the body of a bright scarlet, as in the blush of shame, though by a very different process. In this intricate subject nothing but loose analogical conjectures can be had, which may however lead to future discoveries; but certain it is that both the change of the colour of animals to white in the winters of snowy countries, and the spots on birds eggs, must have some efficient cause; since the uniformity of their production shews it cannot arise from a fortuitous concurrence of circumstances; and how is this efficient cause to be detected, or explained, but from its analogy to other animal facts? 2. The nutriment supplied by the female parent in viviparous animals to their young progeny may be divided into three kinds, corresponding with the age of the new creature. 1. The nutriment contained in the ovum as previously prepared for the embryon in the ovary. 2. The liquor amnii prepared for the fetus in the uterus, and in which it swims; and lastly, the milk prepared in the pectoral glands for the new born-child. There is reason to conclude that variety of changes may be produced in the new animal from all these sources of nutriment, but particularly from the first of them.. The organs of digestion and of sanguification in adults, and afterwards those of secretion, prepare or separate the particles proper for nourishment from other combinations of matter, or recombine them into new kinds of matter, proper to excite into action the filaments, which absorb or attract them by animal appetency. In this process we must attend not only to the action of the living filament which receives a nutritive particle to its bosom, but also to the kind of particle, in respect to form, or size, or colour, or hardness, which is thus previously prepared for it by digestion, sanguification, and secretion. Now as the first filament of entity cannot be furnished with the preparative organs above mentioned, the nutritive particles, which are at first to be received by it, are prepared by the mother; and deposited in the ovum ready for its reception. These nutritive particles must be supposed to differ in some respects, when thus prepared by different animals. They may differ in size, solidity, colour, and form; and yet may be sufficiently congenial to the living filament, to which they are applied, as to excite its activity by their stimulus, and its animal appetency to receive them, and to combine them with itself into organization. By this first nutriment thus prepared for the embryon is not meant the liquor amnii, which is produced afterwards, nor the larger exterior parts of the white of the egg; but the fluid prepared, I suppose, in the ovary of viviparous animals, and that which immediately surrounds the cicatricula of an impregnated egg, and is visible to the eye in a boiled one. Now these ultimate particles of animal matter prepared by the glands of the mother may be supposed to resemble the similar ultimate particles, which were prepared for her own nourishment; that is, to the ultimate particles of which her own organization consists. And that hence when these become combined with a new embryon, which in its early state is not furnished with stomach, or glands, to alter them; that new embryon will bear some resemblance to the mother. This seems to be the origin of the compound forms of mules, which evidently partake of both parents, but principally of the male parent. In this production of chimeras the antients seem to have indulged their fancies, whence the sphinxes, griffins, dragons, centaurs, and minotaurs, which are vanished from modern credulity. It would seem, that in these unnatural conjunctions, when the nutriment deposited by the female was so ill adapted to stimulate the living filament derived from the male into action, and to be received; or embraced by it, and combined with it into organization, as not to produce the organs necessary to life, as the brain, or heart, or stomach, that no mule was produced. Where all the parts necessary to life in these compound animals were formed sufficiently perfect, except the parts of generation, those animals were produced which are now called mules. The formation of the organs of sexual generation, in contradistinction to that by lateral buds, in vegetables, and in some animals, as the polypus, the tænia, and the volvox, seems the chef d'oeuvre, the master-piece of nature; as appears from many flying insects, as in moths and butterflies, who seem to undergo a general change of their forms solely for the purpose of sexual reproduction, and in all other animals this organ is not complete till the maturity of the creature. Whence it happens that, in the copulation of animals of different species, the parts necessary to life are frequently completely formed; but those for the purpose of generation are defective, as requiring a nicer organization; or more exact coincidence of the particles of nutriment to the irritabilities or appetencies of the original living filament. Whereas those mules, where all the parts could be perfectly formed, may have been produced in early periods of time, and may have added to the numbers of our various species of animals, as before observed. As this production of mules is a constant effect from the conjunction of different species of animals, those between the horse and the female ass always resembling the horse more than the ass; and those, on the contrary, between the male ass and the mare, always resembling the ass more than the mare; it cannot be ascribed to the imagination of the male animal which cannot be supposed to operate so uniformly; but to the form of the first nutritive particles, and to their peculiar stimulus exciting the living filament to select and combine them with itself. There is a similar uniformity of effect in respect to the colour of the progeny produced between a white man, and a black woman, which, if I am well informed, is always of the mulatto kind, or a mixture of the two; which may perhaps be imputed to the peculiar form of the particles of nutriment supplied to the embryon by the mother at the early period of its existence, and their peculiar stimulus; as this effect, like that of the mule progeny above treated of, is uniform and consistent, and cannot therefore be ascribed to the imagination of either of the parents. Dr. Thunberg observes, in his Journey to the Cape of Good Hope, that there are some families, which have descended from blacks in the female line for three generations. The first generation proceeding from an European, who married a tawny slave, remains tawny, but approaches to a white complexion; but the children of the third generation, mixed with Europeans, become quite white, and are often remarkably beautiful. V. i. p. 112. When the embryon has produced a placenta, and furnished itself with vessels for selection of nutritious particles, and for oxygenation of them, no great change in its form or colour is likely to be produced by the particles of sustenance it now takes from the fluid, in which it is immersed; because it has now acquired organs to alter or new combine them. Hence it continues to grow, whether this fluid, in which it swims, be formed by the uterus or by any other cavity of the body, as in extra-uterine gestation; and which would seem to be produced by the stimulus of the fetus on the sides of the cavity, where it is found, as mentioned before. And thirdly, there is still less reason to expect any unnatural change to happen to the child after its birth from the difference of the milk it now takes; because it has acquired a stomach, and lungs, and glands, of sufficient power to decompose and recombine the milk; and thus to prepare from it the various kinds of nutritious particles, which the appetencies of the various fibrils or nerves may require. From all this reasoning I would conclude, that though the imagination of the female may be supposed to affect the embryon by producing a difference in its early nutriment; yet that no such power can affect it after it has obtained a placenta, and other organs; which may select or change the food, which is presented to it either in the liquor amnii, or in the milk. Now as the eggs in pullets, like the seeds in vegetables, are produced gradually, long before they are impregnated, it does not appear how any sudden effect of imagination of the mother at the time of impregnation can produce any considerable change in the nutriment already thus laid up for the expected or desired embryon. And that hence any changes of the embryon, except those uniform ones in the production of mules and mulattoes, more probably depend on the imagination of the male parent. At the same time it seems manifest, that those monstrous births, which consist in some deficiencies only, or some redundancies of parts, originate from the deficiency or redundance of the first nutriment prepared in the ovary, or in the part of the egg immediately surrounding the cicatricula, as described above; and which continues some time to excite the first living filament into action, after the simple animal is completed; or ceases to excite it, before the complete form is accomplished. The former of these circumstances is evinced by the eggs with double yolks, which frequently happen to our domesticated poultry, and which, I believe, are so formed before impregnation, but which would be well worth attending to, both before and after impregnation; as it is probable, something valuable on this subject might be learnt from them. The latter circumstance, or that of deficiency of original nutriment, may be deduced from reverse analogy. There are, however, other kinds of monstrous births, which neither depend on deficiency of parts, or supernumerary ones; nor are owing to the conjunction of animals of different species; but which appear to be new conformations, or new dispositions of parts in respect to each other, and which, like the variation of colours and forms of our domesticated animals, and probably the sexual parts of all animals, may depend on the imagination of the male parent, which we now come to consider. VI. 1. The nice actions of the extremities of our various glands are exhibited in their various productions, which are believed to be made by the gland, and not previously to exist as such in the blood. Thus the glands, which constitute the liver, make bile; those of the stomach make gastric acid; those beneath the jaw, saliva; those of the ears, ear-wax; and the like. Every kind of gland must possess a peculiar irritability, and probably a sensibility, at the early state of its existence; and must be furnished with a nerve of sense, or of motion, to perceive, and to select, and to combine the particles, which compose the fluid it secretes. And this nerve of sense which perceives the different articles which compose the blood, must at least be conceived to be as fine and subtile an organ, as the optic or auditory nerve, which perceive light or sound. See Sect. XIV. 9. But in nothing is this nice action of the extremities of the blood-vessels so wonderful, as in the production of contagious matter. A small drop of variolous contagion diffused in the blood, or perhaps only by being inserted beneath the cuticle, after a time, (as about a quarter of a lunation,) excites the extreme vessels of the skin into certain motions, which produce a similar contagious material, filling with it a thousand pustules. So that by irritation, or by sensation in consequence of irritation, or by association of motions, a material is formed by the extremities of certain cutaneous vessels, exactly similar to the stimulating material, which caused the irritation, or consequent sensation, or association. Many glands of the body have their motions, and in consequence their secreted fluids, affected by pleasurable or painful ideas, since they are in many instances influenced by sensitive associations, as well as by the irritations of the particles of the passing blood. Thus the idea of meat, excited in the minds of hungry dogs, by their sense of vision, or of smell, increases the discharge of saliva, both in quantity and viscidity; as is seen in its hanging down in threads from their mouths, as they stand round a dinner-table. The sensations of pleasure, or of pain, of peculiar kinds, excite in the same manner a great discharge of tears; which appear also to be more saline at the time of their secretion, from their inflaming the eyes and eye-lids. The paleness from fear, and the blush of shame, and of joy, are other instances of the effects of painful, or pleasurable sensations, on the extremities of the arterial system. It is probable, that the pleasurable sensation excited in the stomach by food, as well as its irritation, contributes to excite into action the gastric glands, and to produce a greater secretion of their fluids. The same probably occurs in the secretion of bile; that is, that the pleasurable sensation excited in the stomach, affects this secretion by sensitive association, as well as by irritative association. And lastly it would seem, that all the glands in the body have their secreted fluids affected, in quantity and quality, by the pleasurable or painful sensations, which produce or accompany those secretions. And that the pleasurable sensations arising from these secretions may constitute the unnamed pleasure of exigence, which is contrary to what is meant by tedium vitæ, or ennui; and by which we sometimes feel ourselves happy, without being able to ascribe it to any mental cause, as after an agreeable meal, or in the beginning of intoxication. Now it would appear, that no secretion or excretion of fluid is attended with so much agreeable sensation, as that of the semen; and it would thence follow, that the glands, which perform this secretion, are more likely to be much affected by their catenations with pleasurable sensations. This circumstance is certain, that much more of this fluid is produced in a given time, when the object of its exclusion is agreeable to the mind. 2. A forceable argument, which shews the necessity of pleasurable sensation to copulation, is, that the act cannot be performed without it; it is easily interrupted by the pain of fear or bashfulness; and no efforts of volition or of irritation can effect this process, except such as induce pleasurable ideas or sensations. See Sect. XXXIII. 1. 1. A curious analogical circumstance attending hermaphrodite insects, as snails and worms, still further illustrates this theory; if the snail or worm could have impregnated itself, there might have been a saving of a large male apparatus; but as this is not so ordered by nature, but each snail and worm reciprocally receives and gives impregnation, it appears, that a pleasurable excitation seems also to have been required. This wonderful circumstance of many insects being hermaphrodites, and at the same time not having power to impregnate themselves, is attended to by Dr. Lister, in his Exercitationes Anatom. de Limacibus, p. 145; who, amongst many other final causes, which he adduces to account for it, adds, ut tam tristibus et frigidis animalibus majori cum voluptate perficiatur venus. There is, however, another final cause, to which this circumstance may be imputed: it was observed above, that vegetable buds and bulbs, which are produced without a mother, are always exact resemblances of their parent; as appears in grafting fruit-trees, and in the flower-buds of the dioiceous plants, which are always of the same sex on the same tree; hence those hermaphrodite insects, if they could have produced young without a mother, would not have been, capable of that change or improvement, which is seen in all other animals, and in those vegetables, which are procreated by the male embryon received and nourished by the female. And it is hence probable, that if vegetables could only have been produced by buds and bulbs, and not by sexual generation, that there would not at this time have existed one thousandth part of their present number of species; which have probably been originally mule-productions; nor could any kind of improvement or change have happened to them, except by the difference of soil or climate. 3. I conclude, that the imagination of the male at the time of copulation, or at the time of the secretion of the semen, may so affect this secretion by irritative or sensitive association, as described in No. 5. 1. of this section, as to cause the production of similarity of form and of features, with the distinction of sex; as the motions of the chissel of the turner imitate or correspond with those of the ideas of the artist. It is not here to be understood, that the first living fibre, which is to form an animal, is produced with any similarity of form to the future animal; but with propensities, or appetences, which shall produce by accretion of parts the similarity of form, feature, or sex, corresponding to the imagination of the father. Our ideas are movements of the nerves of sense, as of the optic nerve in recollecting visible ideas, suppose of a triangular piece of ivory. The fine moving fibres of the retina act in a manner to which I give the name of white; and this action is confined to a defined part of it; to which figure I give the name of triangle. And it is a preceding pleasurable sensation existing in my mind, which occasions me to produce this particular motion of the retina, when no triangle is present. Now it is probable, that the acting fibres of the ultimate terminations of the secreting apertures of the vessels of the testes, are as fine as those of the retina; and that they are liable to be thrown into that peculiar action, which marks the sex of the secreted embryon, by sympathy with the pleasurable motions of the nerves of vision or of touch; that is, with certain ideas of imagination. From hence it would appear, that the world has long been mistaken in ascribing great power to the imagination of the female, whereas from this account of it, the real power of imagination, in the act of generation, belongs solely to the male. See Sect. XII. 3. 3. It may be objected to this theory, that a man may be supposed to have in his mind, the idea of the form and features of the female, rather than his own, and therefore there should be a greater number of female births. On the contrary, the general idea of our own form occurs to every one almost perpetually, and is termed consciousness of our existence, and thus may effect, that the number of males surpasses that of females. See Sect. XV. 3. 4. and XVIII. 13. And what further confirms this idea is, that the male children most frequently resemble the father in form, or feature, as well as in sex; and the female most frequently resemble the mother, in feature, and form, as well as in sex. It may again be objected, if a female child sometimes resembles the father, and a male child the mother, the ideas of the father, at the time of procreation, must suddenly change from himself to the mother, at the very instant, when the embryon is secreted or formed. This difficulty ceases when we consider, that it is as easy to form an idea of feminine features with male organs of reproduction, or of male features with female ones, as the contrary; as we conceive the idea of a sphinx or mermaid as easily and as distinctly as of a woman. Add to this, that at the time of procreation the idea of the male organs, and of the female features, are often both excited at the same time, by contact, or by vision. I ask, in my turn, is the sex of the embryon produced by accident? Certainly whatever is produced has a cause; but when this cause is too minute for our comprehension, the effect is said in common language to happen by chance, as in throwing a certain number on dice. Now what cause can occasionally produce the male or female character of the embryon, but the peculiar actions of those glands, which form the embryon? And what can influence or govern these actions of the gland, but its associations or catenations with other sensitive motions? Nor is this more extraordinary, than that the catenations of irritative motions with the apparent vibrations of objects at sea should produce sickness of the stomach; or that a nauseous story should occasion vomiting. 4. An argument, which evinces the effect of imagination on the first rudiment of the embryon, may be deduced from the production of some peculiar monsters. Such, for instance, as those which have two heads joined to one body, and those which have two bodies joined to one head; of which frequent examples occur amongst our domesticated quadrupeds, and poultry. It is absurd to suppose, that such forms could exist in primordial germs, as explained in No. IV. 4. of this section. Nor is it possible, that such deformities could be produced by the growth of two embryons, or living filaments; which should afterwards adhere together; as the head and tail part of different polypi are said to do (Blumenbach on Generation, Cadel, London); since in that case one embryon, or living filament, must have begun to form one part first, and the other another part first. But such monstrous conformations become less difficult to comprehend, when they are considered as an effect of the imagination, as before explained, on the living filament at the time of its secretion; and that such duplicature of limbs were produced by accretion of new parts, in consequence of propensities, or animal appetencies thus acquired from the male parent. For instance, I can conceive, if a turkey-cock should behold a rabbit, or a frog, at the time of procreation, that it might happen, that a forcible or even a pleasurable idea of the form of a quadruped might so occupy his imagination, as to cause a tendency in the nascent filament to resemble such a form, by the apposition of a duplicature of limbs. Experiments on the production of mules and monsters would be worthy the attention of a Spallanzani, and might throw much light upon this subject, which at present must be explained by conjectural analogies. The wonderful effect of imagination, both in the male and female parent, is shewn in the production of a kind of milk in the crops both of the male and female pigeons after the birth of their young, as observed by Mr. Hunter, and mentioned before. To this should be added, that there are some instances of men having had milk secreted in their breasts, and who have given suck to children, as recorded by Mr. Buffon. This effect of imagination, of both the male and female parent, seems to have been attended to in very early times; Jacob is said not only to have placed rods of trees, in part stripped of their bark, so as to appear spotted, but also to have placed spotted lambs before the flocks, at the time of their copulation. Genesis, chap. xxx. verse 40. 5. In respect to the imagination of the mother, it is difficult to comprehend, how this can produce any alteration in the fetus, except by affecting the nutriment laid up for its first reception, as described in No. V. 2. of this section, or by affecting the nourishment or oxygenation with which she supplies it afterwards. Perpetual anxiety may probably affect the secretion of the liquor amnii into the uterus, as it enfeebles the whole system; and sudden fear is a frequent cause of miscarriage; for fear, contrary to joy, decreases for a time the action of the extremities of the arterial system; hence sudden paleness succeeds, and a shrinking or contraction of the vessels of the skin, and other membranes. By this circumstance, I imagine, the terminations of the placental vessels are detached from their adhesions, or insertions, into the membrane of the uterus; and the death of the child succeeds, and consequent miscarriage. Of this I recollect a remarkable instance, which could be ascribed to no other cause, and which I shall therefore relate in few words. A healthy young woman, about twenty years of age, had been about five months pregnant, and going down into her cellar to draw some beer, was frighted by a servant boy starting up from behind the barrel, where he had concealed himself with design to alarm the maid-servant, for whom he mistook his mistress. She came with difficulty up stairs, began to flood immediately, and miscarried in a few hours. She has since borne several children, nor ever had any tendency to miscarry of any of them. 6. In respect to the power of the imagination of the male over the form, colour, and sex of the progeny, the following instances have fallen under my observation, and may perhaps be found not very unfrequent, if they were more attended to. I am acquainted with a gentleman, who has one child with dark hair and eyes, though his lady and himself have light hair and eyes; and their other four children are like their parents. On observing this dissimilarity of one child to the others he assured me, that he believed it was his own imagination, that produced the difference; and related to me the following story. He said, that when his lady lay in of her third child, he became attached to a daughter of one of his inferior tenants, and offered her a bribe for her favours in vain; and afterwards a greater bribe, and was equally unsuccessful; that the form of this girl dwelt much in his mind for some weeks, and that the next child, which was the dark-ey'd young lady above mentioned, was exceedingly like, in both features and colour, to the young woman who refused his addresses. To this instance I must add, that I have known two families, in which, on account of an intailed estate in expectation, a male heir was most eagerly desired by the father; and on the contrary, girls were produced to the seventh in one, and to the ninth in another; and then they had each of them a son. I conclude, that the great desire of a male heir by the father produced rather a disagreeable than an agreeable sensation; and that his ideas dwelt more on the fear of generating a female, than on the pleasurable sensations or ideas of his own male form or organs at the time of copulation, or of the secretion of the semen; and that hence the idea of the female character was more present to his mind than that of the male one; till at length in despair of generating a male these ideas ceased, and those of the male character presided at the genial hour. 7. Hence I conclude, that the act of generation cannot exist without being accompanied with ideas, and that a man must have at that time either a general idea of his own male form, or of the form of his male organs; or an idea of the female form, or of her organs; and that this marks the sex, and the peculiar resemblances of the child to either parent. From whence it would appear, that the phalli, which were hung round the necks of the Roman ladies, or worn in their hair, might have effect in producing a greater proportion of male children; and that the calipædia, or art of begetting beautiful children, and of procreating either males or females, may be taught by affecting the imagination of the male-parent; that is, by the fine extremities of the seminal glands, imitating the actions of the organs of sense either of sight or touch. But the manner of accomplishing this cannot be unfolded with sufficient delicacy for the public eye; but may be worth the attention of those, who are seriously interested in the procreation of a male or female child. _Recapitulation._ VII. 1. A certain quantity of nutritive particles are produced by the female parent before impregnation, which require no further digestion, secretion, or oxygenation. Such are seen in the unimpregnated eggs of birds, and in the unimpregnated seed-vessels of vegetables. 2. A living filament is produced by the male, which being inserted amidst these first nutritive particles, is stimulated into action by them; and in consequence of this action, some of the nutritive particles are embraced, and added to the original living filament; in the same manner as common nutrition is performed in the adult animal. 3. Then this new organization, or additional part, becomes stimulated by the nutritive particles in its vicinity, and sensation is now superadded to irritation; and other particles are in consequence embraced, and added to the living filament; as is seen in the new granulations of flesh in ulcers. By the power of association, or by irritation, the parts already produced continue their motions, and new ones are added by sensation, as above mentioned; and lastly by volition, which last sensorial power is proved to exist in the fetus in its maturer age, because it has evidently periods of activity and of sleeping; which last is another word for a temporary suspension of volition. The original living filament may be conceived to possess a power of repulsing the particles applied to certain parts of it, as well as of embracing others, which stimulate other parts of it; as these powers exist in different parts of the mature animal; thus the mouth of every gland embraces the particles or fluid, which suits its appetency; and its excretory duct repulses those particles, which are disagreeable to it. 4. Thus the outline or miniature of the new animal is produced gradually, but in no great length of time; because the original nutritive particles require no previous preparation by digestion, secretion, and oxygenation: but require simply the selection and apposition, which is performed by the living filament. Mr. Blumenbach says, that he possesses a human fetus of only five weeks old, which is the size of a common bee, and has all the features of the face, every finger, and every toe, complete; and in which the organs of generation are distinctly seen. P. 76. In another fetus, whose head was not larger than a pea, the whole of the basis of the skull with all its depressions, apertures, and processes, were marked in the most sharp and distinct manner, though without any ossification. Ib. 5. In some cases by the nutriment originally deposited by the mother the filament acquires parts not exactly similar to those of the father, as in the production of mules and mulattoes. In other cases, the deficiency of this original nutriment causes deficiencies of the extreme parts of the fetus, which are last formed, as the fingers, toes, lips. In other cases, a duplicature of limbs are caused by the superabundance of this original nutritive fluid, as in the double yolks of eggs, and the chickens from them with four legs and four wings. But the production of other monsters, as those with two heads, or with parts placed in wrong situations, seems to arise from the imagination of the father being in some manner imitated by the extreme vessels of the seminal glands; as the colours of the spots on eggs, and the change of the colour of the hair and feathers of animals by domestication, may be caused in the same manner by the imagination of the mother. 6. The living filament is a part of the father, and has therefore certain propensities, or appetencies, which belong to him; which may have been gradually acquired during a million of generations, even from the infancy of the habitable earth; and which now possesses such properties, as would render, by the apposition of nutritious particles, the new fetus exactly similar to the father; as occurs in the buds and bulbs of vegetables, and in the polypus, and tænia or tape-worm. But as the first nutriment is supplied by the mother, and therefore resembles such nutritive particles, as have been used for her own nutriment or growth, the progeny takes in part of the likeness of the mother. Other similarity of the excitability, or of the form of the male parent, such as the broad or narrow shoulders, or such as constitute certain hereditary diseases, as scrophula, epilepsy, insanity, have their origin produced in one or perhaps two generations; as in the progeny of those who drink much vinous spirits; and those hereditary propensities cease again, as I have observed, if one or two sober generations succeed; otherwise the family becomes extinct. This living filament from the father is also liable to have its propensities, or appetencies, altered at the time of its production by the imagination of the male parent; the extremities of the seminal glands imitating the motions of the organs of sense; and thus the sex of the embryon is produced; which may be thus made a male or a female by affecting the imagination of the father at the time of impregnation. See Sect. XXXIX. 6. 3. and 7. 7. After the fetus is thus completely formed together with its umbilical vessels and placenta, it is now supplied with a different kind of food, as appears by the difference of consistency of the different parts of the white of the egg, and of the liquor amnii, for it has now acquired organs for digestion or secretion, and for oxygenation, though they are as yet feeble; which can in some degree change, as well as select, the nutritive particles, which are now presented to it. But may yet be affected by the deficiency of the quantity of nutrition supplied by the mother, or by the degree of oxygenation supplied to its placenta by the maternal blood. The augmentation of the complete fetus by additional particles of nutriment is not accomplished by distention only, but by apposition to every part both external and internal; each of which acquires by animal appetencies the new addition of the particles which it wants. And hence the enlarged parts are kept similar to their prototypes, and may be said to be extended; but their extension must be conceived only as a necessary consequence of the enlargement of all their parts by apposition of new particles. Hence the new apposition of parts is not produced by capillary attraction, because the whole is extended; whereas capillary attraction would rather tend to bring the sides of flexible tubes together, and not to distend them. Nor is it produced by chemical affinities, for then a solution of continuity would succeed, as when sugar is dissolved in water; but it is produced by an animal process, which is the consequence of irritation, or sensation; and which may be termed animal appetency. This is further evinced from experiments, which have been instituted to shew, that a living muscle of an animal body requires greater force to break it, than a similar muscle of a dead body. Which evinces, that besides the attraction of cohesion, which all matter possesses, and besides the chemical attractions of affinities, which hold many bodies together, there is an animal adhesion, which adds vigour to these common laws of the inanimate world. 8. At the nativity of the child it deposits the placenta or gills, and by expanding its lungs acquires more plentiful oxygenation from the currents of air, which it must now continue perpetually to respire to the end of its life; as it now quits the liquid element, in which it was produced, and like the tadpole, when it changes into a frog, becomes an aerial animal. 9. As the habitable parts of the earth have been, and continue to be, perpetually increasing by the production of sea-shells and corallines, and by the recrements of other animals, and vegetables; so from the beginning of the existence of this terraqueous globe, the animals, which inhabit it, have constantly improved, and are still in a state of progressive improvement. This idea of the gradual generation of all things seems to have been as familiar to the ancient philosophers as to the modern ones; and to have given rise to the beautiful hieroglyphic figure of the [Greek: proton ôon], or first great egg, produced by NIGHT, that is, whose origin is involved in obscurity, and animated by [Greek: eros], that is, by DIVINE LOVE; from whence proceeded all things which exist. _Conclusion._ VIII. 1. Cause and effect may be considered as the progression, or successive motions, of the parts of the great system of Nature. The state of things at this moment is the effect of the state of things, which existed in the preceding moment; and the cause of the state of things, which shall exist in the next moment. These causes and effects may be more easily comprehended, if motion be considered as a change of the figure of a group of bodies, as proposed in Sect. XIV. 2. 2. inasmuch as our ideas of visible or tangible objects are more distinct, than our abstracted ideas of their motions. Now the change of the configuration of the system of nature at this moment must be an effect of the preceding configuration, for a change of configuration cannot exist without a previous configuration; and the proximate cause of every effect must immediately precede that effect. For example, a moving ivory ball could not proceed onwards, unless it had previously began to proceed; or unless an impulse had been previously given it; which previous motion or impulse constitutes a part of the last situation of things. As the effects produced in this moment of time become causes in the next, we may consider the progressive motions of objects as a chain of causes only; whose first link proceeded from the great Creator, and which have existed from the beginning of the created universe, and are perpetually proceeding. 2. These causes may be conveniently divided into two kinds, efficient and inert causes, according with the two kinds of entity supposed to exist in the natural world, which may be termed matter and spirit, as proposed in Sect. I. and further treated of in Sect. XIV. The efficient causes of motion, or new configuration, consist either of the principle of general gravitation, which actuates the sun and planets; or of the principle of particular gravitation, as in electricity, magnetism, heat; or of the principle of chemical affinity, as in combustion, fermentation, combination; or of the principle of organic life, as in the contraction of vegetable and animal fibres. The inert causes of motion, or new configuration, consist of the parts of matter, which are introduced within the spheres of activity of the principles above described. Thus, when an apple falls on the ground, the principle of gravitation is the efficient cause, and the matter of the apple the inert cause. If a bar of iron be approximated to a magnet, it may be termed the inert cause of the motion, which brings these two bodies into contact; while the magnetic principle may be termed the efficient cause. In the same manner the fibres, which constitute the retina, may be called the inert cause of the motions of that organ in vision, while the sensorial power may be termed the efficient cause. 3. Another more common distribution of the perpetual chain of causes and effects, which constitute the motions, or changing configurations, of the natural world, is into active and passive. Thus, if a ball in motion impinges against another ball at rest, and communicates its motion to it, the former ball is said to act, and the latter to be acted upon. In this sense of the words a magnet is said to attract iron; and the prick of a spur to stimulate a horse into exertion; so that in this view of the works of nature all things may be said either simply to exist, or to exist as causes, or to exist as effects; that is, to exist either in an active or passive state. This distribution of objects, and their motions, or changes of position, has been found so convenient for the purposes of common life, that on this foundation rests the whole construction or theory of language. The names of the things themselves are termed by grammarians Nouns, and their modes of existence are termed Verbs. The nouns are divided into substantives, which denote the principal things spoken of; and into adjectives, which denote some circumstances, or less kinds of things, belonging to the former. The verbs are divided into three kinds, such as denote the existence of things simply, as, to be; or their existence in an active state, as, to eat; or their existence in a passive state, as, to be eaten. Whence it appears, that all languages consist only of nouns and verbs, with their abbreviations for the greater expedition of communicating our thoughts; as explained in the ingenious work of Mr. Horne Tooke, who has unfolded by a single flash of light the whole theory of language, which had so long lain buried beneath the learned lumber of the schools. Diversions of Purley. Johnson. London. 4. A third division of causes has been into proximate and remote; these have been much spoken of by the writers on medical subjects, but without sufficient precision. If to proximate and remote causes we add proximate and remote effects, we shall include four links of the perpetual chain of causation; which will be more convenient for the discussion of many philosophical subjects. Thus if a particle of chyle be applied to the mouth of a lacteal vessel, it may be termed the remote cause of the motions of the fibres, which compose the mouth of that lacteal vessel; the sensorial power is the proximate cause; the contraction of the fibres of the mouth of the vessel is the proximate effect; and their embracing the particle of chyle is the remote effect; and these four links of causation constitute absorption. Thus when we attend to the rising sun, first the yellow rays of light stimulate the sensorial power residing in the extremities of the optic nerve, this is the remote cause. 2. The sensorial power is excited into a state of activity, this is the proximate cause. 3. The fibrous extremities of the optic nerve are contracted, this is the proximate effect. 4. A pleasurable or painful sensation is produced in consequence of the contraction of these fibres of the optic nerve, this is the remote effect; and these four links of the chain of causation constitute the sensitive idea, or what is commonly termed the sensation of the rising sun. 5. Other causes have been announced by medical writers under the names of causa procatarctica, and causa proegumina, and causa sine quâ non. All which are links more or less distant of the chain of remote causes. To these must be added the final cause, so called by many authors, which means the motive, for the accomplishment of which the preceding chain of causes was put into action. The idea of a final cause, therefore, includes that of a rational mind, which employs means to effect its purposes; thus the desire of preserving himself from the pain of cold, which he has frequently experienced, induces the savage to construct his hut; the fixing stakes into the ground for walls, branches of trees for rafters, and turf for a cover, are a series of successive voluntary exertions; which are so many means to produce a certain effect. This effect of preserving himself from cold, is termed the final cause; the construction of the hut is the remote effect; the action of the muscular fibres of the man, is the proximate effect; the volition, or activity of desire to preserve himself from cold, is the proximate cause; and the pain of cold, which excited that desire, is the remote cause. 6. This perpetual chain of causes and effects, whose first link is rivetted to the throne of GOD, divides itself into innumerable diverging branches, which, like the nerves arising from the brain, permeate the most minute and most remote extremities of the system, diffusing motion and sensation to the whole. As every cause is superior in power to the effect, which it has produced, so our idea of the power of the Almighty Creator becomes more elevated and sublime, as we trace the operations of nature from cause to cause, climbing up the links of these chains of being, till we ascend to the Great Source of all things. Hence the modern discoveries in chemistry and in geology, by having traced the causes of the combinations of bodies to remoter origins, as well as those in astronomy, which dignify the present age, contribute to enlarge and amplify our ideas of the power of the Great First Cause. And had those ancient philosophers, who contended that the world was formed from atoms, ascribed their combinations to certain immutable properties received from the hand of the Creator, such as general gravitation, chemical affinity, or animal appetency, instead of ascribing them to a blind chance; the doctrine of atoms, as constituting or composing the material world by the variety of their combinations, so far from leading the mind to atheism, would strengthen the demonstration of the existence of a Deity, as the first cause of all things; because the analogy resulting from our perpetual experience of cause and effect would have thus been exemplified through universal nature. _The heavens declare the glory of _GOD_, and the firmament sheweth his handywork! One day telleth another, and one night certifieth another; they have neither speech nor language, yet their voice is gone forth into all lands, and their words into the ends of the world. Manifold are thy works, _O LORD!_ in wisdom hast thou made them all._ Psal. xix. civ. * * * * * SECT. XL. On the OCULAR SPECTRA of Light and Colours, by Dr. R. W. Darwin, of Shrewsbury. Reprinted, by Permission, from the Philosophical Transactions, Vol. LXXVI. p. 313. _Spectra of four kinds._ 1. _Activity of the retina in vision._ 2. _Spectra from defect of sensibility._ 3. _Spectra from excess of sensibility_. 4. _Of direct ocular spectra._ 5. _Greater stimulus excites the retina into spasmodic action._ 6. _Of reverse ocular spectra._ 7. _Greater stimulus excites the retina into various successive spasmodic actions._ 8. _Into fixed spasmodic action._ 9. _Into temporary paralysis._ 10. _Miscellaneous remarks;_ 1. _Direct and reverse spectra at the same time. A spectral halo. Rule to predetermine the colours of spectra._ 2. _Variation of spectra from extraneous light._ 3. _Variation of spectra in number, figure, and remission._ 4. _Circulation of the blood in the eye is visible._ 5. _A new way of magnifying objects. Conclusion._ When any one has long and attentively looked at a bright object, as at the setting sun, on closing his eyes, or removing them, an image, which resembles in form the object he was attending to, continues some time to be visible; this appearance in the eye we shall call the ocular spectrum of that object. These ocular spectra are of four kinds: 1st, Such as are owing to a less sensibility of a defined part of the retina; or _spectra from defect of sensibility._ 2d, Such as are owing to a greater sensibility of a defined part of the retina; or _spectra from excess of sensibility_. 3d, Such as resemble their object in its colour as well as form; which may be termed _direct ocular spectra_. 4th, Such as are of a colour contrary to that of their object; which may be termed _reverse ocular spectra_. The laws of light have been most successfully explained by the great Newton, and the perception of visible objects has been ably investigated by the ingenious Dr. Berkeley and M. Malebranche; but these minute phenomena of vision have yet been thought reducible to no theory, though many philosophers have employed a considerable degree of attention upon them: among these are Dr. Jurin, at the end of Dr. Smith's Optics; M. Æpinus, in the Nov. Com. Petropol. V. 10.; M. Beguelin, in the Berlin Memoires, V. II. 1771; M. d'Arcy, in the Histoire de l'Acad. des Scienc. 1765; M. de la Hire; and, lastly, the celebrated M. de Buffon, in the Memoires de l'Acad. des Scien. who has termed them accidental colours, as if subjected to no established laws, Ac. Par. 1743. M. p. 215. I must here apprize the reader, that it is very difficult for different people to give the same names to various shades of colours; whence, in the following pages, something must be allowed, if on repeating the experiments the colours here mentioned should not accurately correspond with his own names of them. I. _Activity of the Retina in Vision._ From the subsequent experiments it appears, that the retina is in an active not in a passive state during the existence of these ocular spectra; and it is thence to be concluded, that all vision is owing to the activity of this organ. 1. Place a piece of red silk, about an inch in diameter, as in plate 1, at Sect. III. 1., on a sheet of white paper, in a strong light; look steadily upon it from about the distance of half a yard for a minute; then closing your eyelids cover them with your hands, and a green spectrum will be seen in your eyes, resembling in form the piece of red silk: after some time, this spectrum will disappear and shortly reappear; and this alternately three or four times, if the experiment is well made, till at length it vanishes entirely. 2. Place on a sheet of white paper a circular piece of blue silk, about four inches in diameter, in the sunshine; cover the center of this with a circular piece of yellow silk, about three inches in diameter; and the center of the yellow silk with a circle of pink silk, about two inches in diameter; and the center of the pink silk with a circle of green silk, about one inch in diameter; and the centre of this with a circle of indigo, about half an inch in diameter; make a small speck with ink in the very center of the whole, as in plate 3, at Sect. III. 3. 6.; look steadily for a minute on this central spot, and then closing your eyes, and applying your hand at about an inch distance before them, so as to prevent too much or too little light from passing through the eyelids, you will see the most beautiful circles of colours that imagination can conceive, which are most resembled by the colours occasioned by pouring a drop or two of oil on a still lake in a bright day; but these circular irises of colours are not only different from the colours of the silks above mentioned, but are at the same time perpetually changing as long as they exist. 3. When any one in the dark presses either corner of his eye with his finger, and turns his eye away from his finger, he will see a circle of colours like those in a peacock's tail: and a sudden flash of light is excited in the eye by a stroke on it. (Newton's Opt. Q. 16.) 4. When any one turns round rapidly on one foot, till he becomes dizzy, and falls upon the ground, the spectra of the ambient objects continue to present themselves in rotation, or appear to librate, and he seems to behold them for some time still in motion. From all these experiments it appears, that the spectra in the eye are not owing to the mechanical impulse of light impressed on the retina, nor to its chemical combination with that organ, nor to the absorption and emission of light, as is observed in many bodies; for in all these cases the spectra must either remain uniformly, or gradually diminish; and neither their alternate pretence and evanescence as in the first experiment, nor the perpetual changes of their colours as in the second, nor the flash of light or colours in the pressed eye as in the third, nor the rotation or libration of the spectra as in the fourth, could exist. It is not absurd to conceive, that the retina may be stimulated into motion, as well as the red and white muscles which form our limbs and vessels; since it consists of fibres, like those, intermixed with its medullary substance. To evince this structure, the retina of an ox's eye was suspended in a glass of warm water, and forcibly torn in a few places; the edges of these parts appeared jagged and hairy, and did not contract, and become smooth like simple mucus, when it is distended till it breaks; which shews that it consists of fibres; and that its fibrous construction became still more distinct to the sight, by adding some caustic alkali to the water, as the adhering mucus was first eroded, and the hair-like fibres remained floating in the vessel. Nor does the degree of transparency of the retina invalidate the evidence of its fibrous structure, since Leeuwenhoek has shewn that the crystalline humour itself consists of fibres. (Arcana Naturæ, V. 1. p. 70.) Hence it appears, that as the muscles have larger fibres intermixed with a smaller quantity of nervous medulla, the organ of vision has a greater quantity of nervous medulla intermixed with smaller fibres; and it is probable that the locomotive muscles, as well as the vascular ones, of microscopic animals have much greater tenuity than these of the retina. And besides the similar laws, which will be shewn in this paper to govern alike the actions of the retina and of the muscles, there are many other analogies which exist between them. They are both originally excited into action by irritations, both are nearly in the same quantity of time, are alike strengthened or fatigued by exertion, are alike painful if excited into action when they are in an inflamed state, are alike liable to paralysis, and to the torpor of old age. II. OF SPECTRA FROM DEFECT OF SENSIBILITY. _The retina is not so easily excited into action by less irritation after having been lately subjected to greater._ 1. When any one passes from the bright daylight into a darkened room, the irises of his eyes expand themselves to their utmost extent in a few seconds of time; but it is very long before the optic nerve, after having been stimulated by the greater light of the day, becomes sensible of the less degree of it in the room; and, if the room is not too obscure, the irises will again contract themselves in some degree, as the sensibility of the retina returns. 2. Place about half an inch square of white paper on a black hat, and looking steadily on the center of it for a minute, remove your eyes to a sheet of white paper; and after a second or two a dark square will be seen on the white paper, which will continue some time. A similar dark square will be seen in the closed eye, if light be admitted through the eyelids. So after looking at any luminous object of a small size, as at the sun, for a short time, so as not much to fatigue the eyes, this part of the retina becomes less sensible to smaller quantities of light; hence, when the eyes are turned on other less luminous parts of the sky, a dark spot is seen resembling the shape of the sun, or other luminous object which we last beheld. This is the source of one kind of the dark-coloured _muscæ volitantes_. If this dark spot lies above the center of the eye, we turn our eyes that way, expecting to bring it into the center of the eye, that we may view it more distinctly; and in this case the dark spectrum seems to move upwards. If the dark spectrum is found beneath the centre of the eye, we pursue it from the same motive, and it seems to move downwards. This has given rise to various conjectures of something floating in the aqueous humours of the eyes; but whoever, in attending to these spots, keeps his eyes unmoved by looking steadily at the corner of a cloud, at the same time that he observes the dark spectra, will be thoroughly convinced, that they have no motion but what is given to them by the movement of our eyes in pursuit of them. Sometimes the form of the spectrum, when it has been received from a circular luminous body, will become oblong; and sometimes it will be divided into two circular spectra, which is not owing to our changing the angle made by the two optic axises, according to the distance of the clouds or other bodies to which the spectrum is supposed to be contiguous, but to other causes mentioned in No. X. 3. of this section. The apparent size of it will also be variable according to its supposed distance. As these spectra are more easily observable when our eyes are a little weakened by fatigue, it has frequently happened, that people of delicate constitutions have been much alarmed at them, fearing a beginning decay of their sight, and have thence fallen into the hands of ignorant oculists; but I believe they never are a prelude to any other disease of the eye, and that it is from habit alone, and our want of attention to them, that we do not see them on all objects every hour of our lives. But as the nerves of very weak people lose their sensibility, in the same manner as their muscles lose their activity, by a small time of exertion, it frequently happens, that sick people in the extreme debility of fevers are perpetually employed in picking something from the bed-clothes, occasioned by their mistaking the appearance of these _muscæ volitantes_ in their eyes. Benvenuto Celini, an Italian artist, a man of strong abilities, relates, that having passed the whole night on a distant mountain with some companions and a conjurer, and performed many ceremonies to raise the devil, on their return in the morning to Rome, and looking up when the sun began to rise, they saw numerous devils run on the tops of the houses, as they passed along; so much were the spectra of their weakened eyes magnified by fear, and made subservient to the purposes of fraud or superstition. (Life of Ben. Celini.) 3. Place a square inch of white paper on a large piece of straw-coloured silk; look steadily some time on the white paper, and then move the centre of your eyes on the silk, and a spectrum of the form of the paper will appear on the silk, of a deeper yellow than the other part of it: for the central part of the retina, having been some time exposed to the stimulus of a greater quantity of white light, is become less sensible to a smaller quantity of it, and therefore sees only the yellow rays in that part of the straw-coloured silk. Facts similar to these are observable in other parts of our system: thus, if one hand be made warm, and the other exposed to the cold, and then both of them immersed in subtepid water, the water is perceived warm to one hand, and cold to the other; and we are not able to hear weak sounds for some time after we have been exposed to loud ones; and we feel a chilliness on coming into an atmosphere of temperate warmth, after having been some time confined in a very warm room: and hence the stomach, and other organs of digestion, of those who have been habituated to the greater stimulus of spirituous liquor, are not excited into their due action by the less stimulus of common food alone; of which the immediate consequence is indigestion and hypochondriacism. III. OF SPECTRA FROM EXCESS OF SENSIBILITY. _The retina is more easily excited into action by greater irritation after having been lately subjected to less._ 1. If the eyes are closed, and covered perfectly with a hat, for a minute or two, in a bright day; on removing the hat a red or crimson light is seen through the eyelids. In this experiment the retina, after being some time kept in the dark, becomes so sensible to a small quantity of light, as to perceive distinctly the greater quantity of red rays than of others which pass through the eyelids. A similar coloured light is seen to pass through the edges of the fingers, when the open hand is opposed to the flame of a candle. 2. If you look for some minutes steadily on a window in the beginning of the evening twilight, or in a dark day, and then move your eyes a little, so that those parts of the retina, on which the dark frame-work of the window was delineated, may now fall on the glass part of it, many luminous lines, representing the frame-work, will appear to lie across the glass panes: for those parts of the retina, which were before least stimulated by the dark frame-work, are now more sensible to light than the other parts of the retina which were exposed to the more luminous parts of the window, 3. Make with ink on white paper a very black spot, about half an inch in diameter, with a tail about an inch in length, so as to represent a tadpole, as in plate 2, at Sect. III. 3. 3.; look steadily for a minute on this spot, and, on moving the eye a little, the figure of the tadpole will be seen on the white part of the paper, which figure of the tadpole will appear whiter or more luminous than the other parts of the white paper; for the part of the retina on which the tadpole was delineated, is now more sensible to light, than the other parts of it, which were exposed to the white paper. This experiment is mentioned by Dr. Irwin, but is not by him ascribed to the true cause, namely, the greater sensibility of that part of the retina which has been exposed to the black spot, than of the other parts which had received the white field of paper, which is put beyond a doubt by the next experiment. 4. On closing the eyes after viewing the black spot on the white paper, as in the foregoing experiment, a red spot is seen of the form of the black spot: for that part of the retina, on which the black spot was delineated, being now more sensible to light than the other parts of it, which were exposed to the white paper, is capable of perceiving the red rays which penetrate the eyelids. If this experiment be made by the light of a tallow candle, the spot will be yellow instead of red; for tallow candles abound much with yellow light, which passes in greater quantity and force through the eyelids than blue tight; hence the difficulty of distinguishing blue and green by this kind of candle light. The colour of the spectrum may possibly vary in the daylight, according to the different colour of the meridian or the morning or evening light. M. Beguelin, in the Berlin Memoires, V. II. 1771, observes, that, when he held a book so that the sun shone upon his half-closed eyelids, the black letters, which he had long inspected, became red, which must have been thus occasioned. Those parts of the retina which had received for some time the black letters, were so much more sensible than those parts which had been opposed to the white paper, that to the former the red light, which passed through the eyelids, was perceptible. There is a similar story told, I think, in de Voltaire's Historical Works, of a Duke of Tuscany, who was playing at dice with the general of a foreign army, and, believing he saw bloody spots upon the dice, portended dreadful events, and retired in confusion. The observer, after looking for a minute on the black spots of a die, and carelessly closing his eyes, on a bright day; would see the image of a die with red spots upon it, as above explained. 5. On emerging from a dark cavern, where we have long continued, the light of a bright day becomes intolerable to the eye for a considerable time, owing to the excess of sensibility existing in the eye, after having been long exposed to little or no stimulus. This occasions us immediately to contract the iris to its smallest aperture, which becomes again gradually dilated, as the retina becomes accustomed to the greater stimulus of the daylight. The twinkling of a bright star, or of a distant candle in the night, is perhaps owing to the same cause. While we continue to look upon these luminous objects, their central parts gradually appear paler, owing to the decreasing sensibility of the part of the retina exposed to their light; whilst, at the same time, by the unsteadiness of the eye, the edges of them are perpetually falling on parts of the retina that were just before exposed to the darkness of the night, and therefore tenfold more sensible to light than the part on which the star or candle had been for some time delineated. This pains the eye in a similar manner as when we come suddenly from a dark room into bright daylight, and gives the appearance of bright scintillations. Hence the stars twinkle most when the night is darkest, and do not twinkle through telescopes, as observed by Musschenbroeck; and it will afterwards be seen why this twinkling is sometimes of different colours when the object is very bright, as Mr. Melvill observed in looking at Sirius. For the opinions of others on this subject, see Dr. Priestley's valuable History of Light and Colours, p. 494. Many facts observable in the animal system are similar to these; as the hot glow occasioned by the usual warmth of the air, or our clothes, on coming out of a cold bath; the pain of the fingers on approaching the fire after having handled snow; and the inflamed heels from walking in snow. Hence those who have been exposed to much cold have died on being brought to a fire, or their limbs have become so much inflamed as to mortify. Hence much food or wine given suddenly to those who have almost perished by hunger has destroyed them; for all the organs of the famished body are now become so much more irritable to the stimulus of food and wine, which they have long been deprived of, that inflammation is excited, which terminates in gangrene or fever. IV. OF DIRECT OCULAR SPECTRA. _A quantity of stimulus somewhat greater than natural excites the retina into spasmodic action, which ceases in a few seconds._ A certain duration and energy of the stimulus of light and colours excites the perfect action of the retina in vision; for very quick motions are imperceptible to us, as well as very slow ones, as the whirling of a top, or the shadow on a sun-dial. So perfect darkness does not affect the eye at all; and excess of light produces pain, not vision. 1. When a fire-coal is whirled round in the dark, a lucid circle remains a considerable time in the eye; and that with so much vivacity of light, that it is mistaken for a continuance of the irritation of the object. In the same manner, when a fiery meteor shoots across the night, it appears to leave a long lucid train behind it, part of which, and perhaps sometimes the whole, is owing to the continuance of the action of the retina after having been thus vividly excited. This is beautifully illustrated by the following experiment: fix a paper sail, three or four inches in diameter, and made like that of a smoke jack, on a tube of pasteboard; on looking through the tube at a distant prospect, some disjointed parts of it will be seen through the narrow intervals between the sails; but as the fly begins to revolve, these intervals appear larger; and when it revolves quicker, the whole prospect is seen quite as distinct as if nothing intervened, though less luminous. [Illustration: Fig. 3.] 2. Look through a dark tube, about half a yard long, at the area of a yellow circle of half an inch diameter, lying upon a blue area of double that diameter, for half a minute; and on closing your eyes the colours of the spectrum will appear similar to the two areas, as in fig. 3.; but if the eye is kept too long upon them, the colours of the spectrum will be the reverse of those upon the paper, that is, the internal circle will become blue, and the external area yellow; hence some attention is required in making this experiment. 3. Place the bright flame of a spermaceti candle before a black object in the night; look steadily at it for a short time, till it is observed to become somewhat paler; and on closing the eyes, and covering them carefully, but not so as to compress them, the image of the blazing candle will continue distinctly to be visible. 4. Look steadily, for a short time, at a window in a dark day, as in Exp. 2. Sect. III. and then closing your eyes, and covering them with your hands, an exact delineation of the window remains for some time visible in the eye. This experiment requires a little practice to make it succeed well; since, if the eyes are fatigued by looking too long on the window, or the day be too bright, the luminous parts of the window will appear dark in the spectrum, and the dark parts of the frame-work will appear luminous, as in Exp. 2. Sect. III. And it is even difficult for many, who first try this experiment, to perceive the spectrum at all; for any hurry of mind, or even too great attention to the spectrum itself, will disappoint them, till they have had a little experience in attending to such small sensations. The spectra described in this section, termed direct ocular spectra, are produced without much fatigue of the eye; the irritation of the luminous object being soon withdrawn, or its quantity of light being not so great as to produce any degree of uneasiness in the organ of vision; which distinguishes them from the next class of ocular spectra, which are the consequence of fatigue. These direct spectra are best observed in such circumstances that no light, but what comes from the object, can fall upon the eye; as in looking through a tube, of half a yard long, and an inch wide, at a yellow paper on the side of a room, the direct spectrum was easily produced on closing the eye without taking it from the tube; but if the lateral light is admitted through the eyelids, or by throwing the spectrum on white paper, it becomes a reverse spectrum, as will be explained below. The other senses also retain for a time the impressions that have been made upon them, or the actions they have been excited into. So if a hard body is pressed upon the palm of the hand, as is practised in tricks of legerdemain, it is not easy to distinguish for a few seconds whether it remains or is removed; and tastes continue long to exist vividly in the mouth, as the smoke of tobacco, or the taste of gentian, after the sapid material is withdrawn. V. _A quantity of stimulus somewhat greater than the last mentioned excites the retina into spasmodic action, which ceases and recurs alternately._ 1. On looking for a time on the setting sun, so as not greatly to fatigue the sight, a yellow spectrum is seen when the eyes are closed and covered, which continues for a time, and then disappears and recurs repeatedly before it entirely vanishes. This yellow spectrum of the sun when the eyelids are opened becomes blue; and if it is made to fall on the green grass, or on other coloured objects, it varies its own colour by an intermixture of theirs, as will be explained in another place. 2. Place a lighted spermaceti candle in the night about one foot from your eye, and look steadily on the centre of the flame, till your eye becomes much more fatigued than in Sect. IV. Exp. 3.; and on closing your eyes a reddish spectrum will be perceived, which will cease and return alternately. The action of vomiting in like manner ceases, and is renewed by intervals, although the emetic drug is thrown up with the first effort: so after-pains continue some time after parturition; and the alternate pulsations of the heart of a viper are renewed for some time after it is cleared from its blood. VI. OF REVERSE OCULAR SPECTRA. _The retina, after having been excited into action by a stimulus somewhat greater them the last mentioned falls into opposite spasmodic action._ The actions of every part of animal bodies may be advantageously compared with each other. This strict analogy contributes much to the investigation of truth; while those looser analogies, which compare the phenomena of animal life with those of chemistry or mechanics, only serve to mislead our inquiries. When any of our larger muscles have been in long or in violent action, and their antagonists have been at the same time extended, as soon as the action of the former ceases, the limb is stretched the contrary way for our ease, and a pandiculation or yawning takes place. By the following observations it appears, that a similar circumstance obtains in the organ of vision; after it has been fatigued by one kind of action, it spontaneously falls into the opposite kind. 1. Place a piece of coloured silk, about an inch in diameter, on a sheet of white paper, about half a yard from your eyes; look steadily upon it for a minute; then remove your eyes upon another part of the white paper, and a spectrum will be seen of the form of the silk thus inspected, but of a colour opposite to it. A spectrum nearly similar will appear if the eyes are closed, and the eyelids shaded by approaching the hand near them, so as to permit some, but to prevent too much light falling on them. Red silk produced a green spectrum. Green produced a red one. Orange produced blue. Blue produced orange. Yellow produced violet. Violet produced yellow. That in these experiments the colours of the spectra are the reverse of the colours which occasioned them, may be seen by examining the third figure in Sir Isaac Newton's Optics, L. II. p. 1, where those thin laminæ of air, which reflected yellow, transmitted violet; those which reflected red, transmitted a blue green; and so of the rest, agreeing with the experiments above related. 2. These reverse spectra are similar to a colour, formed by a combination of all the primary colours except that with which the eye has been fatigued in making the experiment: thus the reverse spectrum of red must be such a green as would be produced by a combination of all the other prismatic colours. To evince this fact the following satisfactory experiment was made. The prismatic colours were laid on a circular pasteboard wheel, about four inches in diameter, in the proportions described in Dr. Priestley's History of Light and Colours, pl. 12. fig. 83. except that the red compartment was entirely left out, and the others proportionably extended so as to complete the circle. Then, as the orange is a mixture of red and yellow, and as the violet is a mixture of red and indigo, it became necessary to put yellow on the wheel instead of orange, and indigo instead of violet, that the experiment might more exactly quadrate with the theory it was designed to establish or confute; because in gaining a green spectrum from a red object, the eye is supposed to have become insensible to red light. This wheel, by means of an axis, was made to whirl like a top; and on its being put in motion, a green colour was produced, corresponding with great exactness to the reverse spectrum of red. 3. In contemplating any one or these reverse spectra in the closed and covered eye, it disappears and re-appears several times successively, till at length it entirely vanishes, like the direct spectra in Sect. V.; but with this additional circumstance, that when the spectrum becomes faint or evanescent, it is instantly revived by removing the hand from before the eyelids, so as to admit more light: because then not only the fatigued part of the retina is inclined spontaneously to fall into motions of a contrary direction, but being still sensible to all other rays of light, except that with which it was lately fatigued, is by these rays at the same time stimulated into those motions which form the reverse spectrum. From these experiments there is reason to conclude, that the fatigued part of the retina throws itself into a contrary mode of action, like oscitation or pandiculation, as soon as the stimulus which has fatigued it is withdrawn; and that it still remains sensible, that is, liable to be excited into action by any other colours at the same time, except the colour with which it has been fatigued. VII. _The retina after having been excited into action by a stimulus somewhat greater than the last mentioned falls into various successive spasmodic actions._ 1. On looking at the meridian sun as long as the eyes can well bear its brightness, the disk first becomes pale, with a luminous crescent, which seems to librate from one edge of it to the other, owing to the unsteadiness of the eye; then the whole phasis of the sun becomes blue, surrounded with a white halo; and on closing the eyes, and covering them with the hands, a yellow spectrum is seen, which in a little time changes into a blue one. M. de la Hire observed, after looking at the bright sun, that the impression in his eye first assumed a yellow appearance, and then green, and then blue; and wishes to ascribe these appearances to some affection of the nerves. (Porterfield on the Eye, Vol. I. p. 313.) 2. After looking steadily on about an inch square of pink silk, placed on white paper, in a bright sunshine, at the distance of a foot from my eyes, and closing and covering my eyelids, the spectrum of the silk was at first a dark green, and the spectrum of the white paper became of a pink. The spectra then both disappeared; and then the internal spectrum was blue; and then, after a second disappearance, became yellow, and lastly pink, whilst the spectrum of the field varied into red and green. These successions of different coloured spectra were not exactly the same in the different experiments, though observed, as near as could be, with the same quantity of light, and other similar circumstances; owing, I suppose, to trying too many experiments at a time; so that the eye was not quite free from the spectra of the colours which were previously attended to. The alternate exertions of the retina in the preceding section resembled the oscitation or pandiculation of the muscles, as they were performed in directions contrary to each other, and were the consequence of fatigue rather than of pain. And in this they differ from the successive dissimilar exertions of the retina, mentioned in this section, which resemble in miniature the more violent agitations of the limbs in convulsive diseases, as epilepsy, chorea S. Viti, and opisthotonos; all which diseases are perhaps, at first, the consequence of pain, and have their periods afterwards established by habit. VIII. _The retina, after having been excited into action by a stimulus somewhat greater than the last mentioned falls into a fixed spasmodic action, which continues for some days._ 1. After having looked long at the meridian sun, in making some of the preceding experiments, till the disks faded into a pale blue, I frequently observed a bright blue spectrum of the sun on other objects all the next and the succeeding day, which constantly occurred when I attended to it, and frequently when I did not previously attend to it. When I closed and covered my eyes, this appeared of a dull yellow; and at other times mixed with the colours of other objects on which it was thrown. It may be imagined, that this part of the retina was become insensible to white light, and thence a bluish spectrum became visible on all luminous objects; but as a yellowish spectrum was also seen in the closed and covered eye, there can remain no doubt of this being the spectrum of the sun. A similar appearance was observed by M. Æpinus, which he acknowledges he could give no account of. (Nov. Com. Petrop. V. 10. p. 2. and 6.) The locked jaw, and some cataleptic spasms, are resembled by this phenomenon; and from hence we may learn the danger to the eye by inspecting very luminous objects too long a time. IX. _A quantity of stimulus greater than the preceding induces a temporary paralysis of the organ of vision._ 1. Place a circular piece of bright red silk, about half an inch in diameter, on the middle of a sheet of white paper; lay them on the floor in a bright sunshine, and fixing your eyes steadily on the center of the red circle, for three or four minutes, at the distance of four or six feet from the object, the red silk will gradually become paler, and finally cease to appear red at all. 2. Similar to these are many other animal facts; as purges, opiates, and even poisons, and contagious matter, cease to stimulate our system, after we have been habituated to their use. So some people sleep undisturbed by a clock, or even by a forge hammer in their neighbourhood: and not only continued irritations, but violent exertions of any kind, are succeeded by temporary paralysis. The arm drops down after violent action, and continues for a time useless; and it is probable, that those who have perished suddenly in swimming, or in scating on the ice, have owed their deaths to the paralysis, or extreme fatigue, which succeeds every violent and continued exertion. X. MISCELLANEOUS REMARKS. There were some circumstances occurred in making these experiments, which were liable to alter the results of them, and which I shall here mention for the assistance of others, who may wish to repeat them. 1. _Of direct and inverse spectra existing at the same time_; _of reciprocal direct spectra_; _of a combination of direct and inverse spectra_; _of a spectral halo_; _rules to pre-determine the colours of spectra_. a. When an area, about six inches square, of bright pink Indian paper, had been viewed on an area, about a foot square, of white writing paper, the internal spectrum in the closed eye was green, being the reverse spectrum of the pink paper; and the external spectrum was pink, being the direct spectrum of the pink paper. The same circumstance happened when the internal area was white, and external one pink; that is, the internal spectrum was pink, and the external one green. All the same appearances occurred when the pink paper was laid on a black hat. b. When six inches square of deep violet polished paper was viewed on a foot square of white writing paper, the internal spectrum was yellow, being the reverse spectrum of the violet paper, and the external one was violet, being the direct spectrum of the violet paper. c. When six inches square of pink paper was viewed on a foot square of blue paper, the internal spectrum was blue, and the external spectrum was pink; that is, the internal one was the direct spectrum of the external object, and the external one was the direct spectrum of the internal object, instead of their being each the reverse spectrum of the objects they belonged to. d. When six inches square of blue paper were viewed on a foot square of yellow paper, the interior spectrum became a brilliant yellow, and the exterior one a brilliant blue. The vivacity of the spectra was owing to their being excited both by the stimulus of the interior and exterior objects; so that the interior yellow spectrum was both the reverse spectrum of the blue paper, and the direct one of the yellow paper; and the exterior blue spectrum was both the reverse spectrum of the yellow paper, and the direct one of the blue paper. e. When the internal area was only a square half-inch of red paper, laid on a square foot of dark violet paper, the internal spectrum was green, with a reddish-blue halo. When the red internal paper was two inches square, the internal spectrum was a deeper green, and the external one redder. When the internal paper was six inches square, the spectrum of it became blue, and the spectrum of the external paper was red. f. When a square half-inch of blue paper was laid on a six-inch square of yellow paper, the spectrum of the central paper in the closed eye was yellow, incircled with a blue halo. On looking long on the meridian sun, the disk fades into a pale blue surrounded with a whitish halo. These circumstances, though they very much perplexed the experiments till they were investigated, admit of a satisfactory explanation; for while the rays from the bright internal object in exp. a. fall with their full force on the center of the retina, and, by fatiguing that part of it, induce the reverse spectrum, many scattered rays, from the same internal pink paper, fall on the more external parts of the retina, but not in such quantity as to occasion much fatigue, and hence induce the direct spectrum of the pink colour in those parts of the eye. The same reverse and direct spectra occur from the violet paper in exp. b.: and in exp. c. the scattered rays from the central pink paper produce a direct spectrum of this colour on the external parts of the eye, while the scattered rays from the external blue paper produce a direct spectrum of that colour on the central part of the eye, instead of these parts of the retina falling reciprocally into their reverse spectra. In exp. d. the colours being the reverse of each other, the scattered rays from the exterior object falling on the central parts of the eye, and there exciting their direct spectrum, at the same time that the retina was excited into a reverse spectrum by the central object, and this direct and reverse spectrum being of similar colour, the superior brilliancy of this spectrum was produced. In exp. e. the effect of various quantities of stimulus on the retina, from the different respective sizes of the internal and external areas, induced a spectrum of the internal area in the center of the eye, combined of the reverse spectrum of that internal area and the direct one of the external area, in various shades of colour, from a pale green to a deep blue, with similar changes in the spectrum of the external area. For the same reasons, when an internal bright object was small, as in exp. f. instead of the whole of the spectrum of the external object being reverse to the colour of the internal object, only a kind of halo, or radiation of colour, similar to that of the internal object, was spread a little way on the external spectrum. For this internal blue area being so small, the scattered rays from it extended but a little way on the image of the external area of yellow paper, and could therefore produce only a blue halo round the yellow spectrum in the center. If any one should suspect that the scattered rays from the exterior coloured object do not intermix with the rays from the interior coloured object, and thus affect the central part of the eye, let him look through an opake tube, about two feet in length, and an inch in diameter, at a coloured wall of a room with one eye, and with the other eye naked; and he will find, that by shutting out the lateral light, the area of the wall seen through a tube appears as if illuminated by the sunshine, compared with the other parts of it; from whence arises the advantage of looking through a dark tube at distant paintings. Hence we may safely deduce the following rules to determine before-hand the colours of all spectra. 1. The direct spectrum without any lateral light is an evanescent representation of its object in the unfatigued eye. 2. With some lateral light it becomes of a colour combined of the direct spectrum of the central object, and of the circumjacent objects, in proportion to their respective quantity and brilliancy. 3. The reverse spectrum without lateral light is a representation in the fatigued eye of the form of its objects, with such a colour as would be produced by all the primary colours, except that of the object. 4. With lateral light the colour is compounded of the reverse spectrum of the central object, and the direct spectrum of the circumjacent objects, in proportion to their respective quantity and brilliancy. 2. _Variation and vivacity of the spectra occasioned by extraneous light._ The reverse spectrum, as has been before explained, is similar to a colour, formed by a combination of all the primary colours, except that with which the eye has been fatigued in making the experiment: so the reverse spectrum of red is such a green as would be produced by a combination of all the other prismatic colours. Now it must be observed, that this reverse spectrum of red is therefore the direct spectrum of a combination of all the other prismatic colours, except the red; whence, on removing the eye from a piece of red silk to a sheet of white paper, the green spectrum, which is perceived, may either be called the reverse spectrum of the red silk, or the direct spectrum of all the rays from the white paper, except the red; for in truth it is both. Hence we see the reason why it is not easy to gain a direct spectrum of any coloured object in the day-time, where there is much lateral light, except of very bright objects, as of the setting sun, or by looking through an opake tube; because the lateral external light falling also on the central part of the retina, contributes to induce the reverse spectrum, which is at the same time the direct spectrum of that lateral light, deducting only the colour of the central object which we have been viewing. And for the same reason, it is difficult to gain the reverse spectrum, where there is no lateral light to contribute to its formation. Thus, in looking through an opake tube on a yellow wall, and closing my eye, without admitting any lateral light, the spectra were all at first yellow; but at length changed into blue. And on looking in the same manner on red paper, I did at length get a green spectrum; but they were all at first red ones: and the same after looking at a candle in the night. The reverse spectrum was formed with greater facility when the eye was thrown from the object on a sheet of white paper, or when light was admitted through the closed eyelids; because not only the fatigued part of the retina was inclined spontaneously to fall into motions of a contrary direction; but being still sensible to all other rays of light except that with which it was lately fatigued, was by these rays stimulated at the same time into those motions which form the reverse spectrum. Hence, when, the reverse spectrum of any colour became faint, it was wonderfully revived by admitting more light through the eyelids, by removing the hand from before them: and hence, on covering the closed eyelids, the spectrum would often cease for a time, till the retina became sensible to the stimulus of the smaller quantity of light, and then it recurred. Nor was the spectrum only changed in vivacity, or in degree, by this admission of light through the eyelids; but it frequently happened, after having viewed bright objects, that the spectrum in the closed and covered eye was changed into a third spectrum, when light was admitted through the eyelids: which third spectrum was composed of such colours as could pass through the eyelids, except those of the object. Thus, when an area of half an inch diameter of pink paper was viewed on a sheet of white paper in the sunshine, the spectrum with closed and covered eyes was green; but on removing the hands from before the closed eyelids, the spectrum became yellow, and returned instantly again to green, as often as the hands were applied to cover the eyelids, or removed from them: for the retina being now insensible to red light, the yellow rays passing through the eyelids in greater quantity than the other colours, induced a yellow spectrum; whereas if the spectrum was thrown on white paper, with the eyes open, it became only a lighter green. Though a certain quantity of light facilitates the formation of the reverse spectrum, a greater quantity prevents its formation, as the more powerful stimulus excites even the fatigued parts of the eye into action; otherwise we should see the spectrum of the last viewed object as often as we turn our eyes. Hence the reverse spectra are best seen by gradually approaching the hand near the closed eyelids to a certain distance only, which must be varied with the brightness of the day, or the energy of the spectrum. Add to this, that all dark spectra, as black, blue, or green, if light be admitted through the eyelids, after they have been some time covered, give reddish spectra, for the reasons given in Sect. III. Exp. 1. From these circumstances of the extraneous light coinciding with the spontaneous efforts of the fatigued retina to produce a reverse spectrum, as was observed before, it is not easy to gain a direct spectrum, except of objects brighter than the ambient light; such as a candle in the night, the setting sun, or viewing a bright object through an opake tube; and then the reverse spectrum is instantaneously produced by the admission of some external light; and is as instantly converted again to the direct spectrum by the exclusion of it. Thus, on looking at the setting sun, on closing the eyes, and covering them, a yellow spectrum is seen, which is the direct spectrum of the setting sun; but on opening the eyes on the sky, the yellow spectrum is immediately changed into a blue one, which is the reverse spectrum of the yellow sun, or the direct spectrum of the blue sky, or a combination of both. And this is again transformed into a yellow one on closing the eyes, and so reciprocally, as quick as the motions of the opening and closing eyelids. Hence, when Mr. Melvill observed the scintillations of the star Sirius to be sometimes coloured, these were probably the direct spectrum of the blue sky on the parts of the retina fatigued by the white light of the star. (Essays Physical and Literary, p. 81. V. 2.) When a direct spectrum is thrown on colours darker than itself, it mixes with them; as the yellow spectrum of the setting sun, thrown on the green grass, becomes a greener yellow. But when a direct spectrum is thrown on colours brighter than itself, it becomes instantly changed into the reverse spectrum, which mixes with those brighter colours. So the yellow spectrum of the setting sun thrown on the luminous sky becomes blue, and changes with the colour or brightness of the clouds on which it appears. But the reverse spectrum mixes with every kind of colour on which it is thrown, whether brighter than itself or not; thus the reverse spectrum, obtained by viewing a piece of yellow silk, when thrown on white paper, was a lucid blue green; when thrown on black Turkey leather, becomes a deep violet. And the spectrum of blue silk, thrown on white paper, was a light yellow; on black silk was an obscure orange; and, the blue spectrum, obtained from orange-coloured silk, thrown on yellow, became a green. In these cases the retina is thrown into activity or sensation by the stimulus of external colours, at the same time that it continues the activity or sensation which forms the spectra; in the same manner as the prismatic colours, painted on a whirling top, are seen to mix together. When these colours of external objects are brighter than the direct spectrum which is thrown upon them, they change it into the reverse spectrum, like the admission of external light on a direct spectrum, as explained above. When they are darker than the direct spectrum, they mix with it, their weaker stimulus being inefficient to induce the reverse spectrum. 3. _Variation of spectra in respect to number, and figure, and remission._ [Illustration: Fig. 4.] When we look long and attentively at any object, the eye cannot always be kept entirely motionless; hence, on inspecting a circular area of red silk placed on white paper, a lucid crescent or edge is seen to librate on one side or other of the red circle: for the exterior parts of the retina sometimes falling on the edge of the central silk, and sometimes on the white paper, are less fatigued with red light than the central part of the retina, which is constantly, exposed to it; and therefore, when they fall on the edge of the red silk, they perceive it more vividly. Afterwards, when the eye becomes fatigued, a green spectrum in the form of a crescent is seen to librate on one side or other of the central circle, as by the unsteadiness of the eye a part of the fatigued retina falls on the white paper; and as by the increasing fatigue of the eye the central part of the silk appears paler, the edge on which the unfatigued part of the retina occasionally falls will appear of a deeper red than the original silk, because it is compared with the pale internal part of it. M. de Buffon in making this experiment observed, that the red edge of the silk was not only deeper coloured than the original silk; but, on his retreating a little from it, it became oblong, and at length divided into two, which must have been owing to his observing it either before or behind the point of intersection of the two optic axises. Thus, if a pen is held up before a distant candle, when we look intensely at the pen two candles are seen behind it; when we look intensely at the candle two pens are seen. If the sight be unsteady at the time of beholding the sun, even though one eye only be used, many images of the sun will appear, or luminous lines, when the eye is closed. And as some parts of these will be more vivid than others, and some parts of them will be produced nearer the center of the eye than others, these will disappear sooner than the others; and hence the number and shape of these spectra of the sun will continually vary, as long as they exist. The cause of some being more vivid than others, is the unsteadiness of the eye of the beholder, so that some parts of the retina have been longer exposed to the sunbeams. That some parts of a complicated spectrum fade and return before other parts of it, the following experiment evinces. Draw three concentric circles; the external one an inch and a half in diameter, the middle one an inch, and the internal one half an inch; colour the external and internal areas blue, and the remaining one yellow, as in Fig. 4.; after having looked about a minute on the center of these circles, in a bright light, the spectrum of the external area appears first in the closed eye, then the middle area, and lastly the central one; and then the central one disappears, and the others in inverted order. If concentric circles of more colours are added, it produces the beautiful ever changing spectrum in Sect. I. Exp. 2. From hence it would seem, that the center of the eye produces quicker remissions of spectra, owing perhaps to its greater sensibility; that is, to its more energetic exertions. These remissions of spectra bear some analogy to the tremors of the hands, and palpitations of the heart, of weak people: and perhaps a criterion of the strength of any muscle or nerve may be taken from the time it can be continued in exertion. 4. _Variation of spectra in respect to brilliancy; the visibility of the circulation of the blood in the eye._ 1. The meridian or evening light makes a difference in the colours of some spectra; for as the sun descends, the red rays, which are less refrangible by the convex atmosphere, abound in great quantity. Whence the spectrum of the light parts of a window at this time, or early in the morning, is red; and becomes blue either a little later or earlier; and white in the meridian day; and is also variable from the colour of the clouds or sky which are opposed to the window. 2. All these experiments are liable to be confounded, if they are made too soon after each other, as the remaining spectrum will mix with the new ones. This is a very troublesome circumstance to painters, who are obliged to look long upon the same colour; and in particular to those whose eyes, from natural debility, cannot long, continue the same kind of exertion. For the same reason, in making these experiments, the result becomes much varied if the eyes, after viewing any object, are removed on other objects for but an instant of time, before we close them to view the spectrum; for the light from the object, of which we had only a transient view, in the very time of closing our eyes acts as a stimulus on the fatigued retina; and for a time prevents the defined spectrum from appearing, or mixes its own spectrum with it. Whence, after the eyelids are closed, either a dark field, or some unexpected colours, are beheld for a few seconds, before the desired spectrum becomes distinctly visible. 3. The length of time taken up in viewing an object, of which we are to observe the spectrum, makes a great difference in the appearance of the spectrum, not only in its vivacity, but in its colour; as the direct spectrum of the central object, or of the circumjacent ones, and also the reverse spectra of both, with their various combinations, as well as the time of their duration in the eye, and of their remissions or alternations, depend upon the degree of fatigue the retina is subjected to. The Chevalier d'Arcy constructed a machine by which a coal of fire was whirled round in the dark, and found, that when a luminous body made a revolution in eight thirds of time, it presented to the eye a complete circle of fire; from whence he concludes, that the impression continues on the organ about the seventh part of a second. (Mem. de l'Acad. des Sc. 1765.) This, however, is only to be considered as the shortest time of the duration of these direct spectra; since in the fatigued eye both the direct and reverse spectra, with their intermissions, appear to take up many seconds of time, and seem very variable in proportion to the circumstances of fatigue or energy. 4. It sometimes happens, if the eyeballs have been rubbed hard with the fingers, that lucid sparks are seen in quick motion amidst the spectrum we are attending to. This is similar to the flashes of fire from a stroke on the eye in fighting, and is resembled by the warmth and glow, which appears upon the skin after friction, and is probably owing to an acceleration of the arterial blood into the vessels emptied by the previous pressure. By being accustomed to observe such small sensations in the eye, it is easy to see the circulation of the blood in this organ. I have attended to this frequently, when I have observed my eyes more than commonly sensible to other spectra. The circulation may be seen either in both eyes at a time, or only in one of them; for as a certain quantity of light is necessary to produce this curious phenomenon, if one hand be brought nearer the closed eyelids than the other, the circulation in that eye will for a time disappear. For the easier viewing the circulation, it is sometimes necessary to rub the eyes with a certain degree of force after they are closed, and to hold the breath rather longer than is agreeable, which, by accumulating more blood in the eye, facilitates the experiment; but in general it may be seen distinctly after having examined other spectra with your back to the light, till the eyes become weary; then having covered your closed eyelids for half a minute, till the spectrum is faded away which you were examining, turn your face to the light, and removing your hands from the eyelids, by and by again shade them a little, and the circulation becomes curiously distinct. The streams of blood are however generally seen to unite, which shews it to be the venous circulation, owing, I suppose, to the greater opacity of the colour of the blood in these vessels; for this venous circulation is also much more easily seen by the microscope in the tail of a tadpole. 5. _Variation of spectra in respect to distinctness and size; with a new way of magnifying objects._ 1. It was before observed, that when the two colours viewed together were opposite to each other, as yellow and blue, red and green, &c. according to the table of reflections and transmissions of light in Sir Isaac Newton's Optics, B. II. Fig. 3. the spectra of those colours were of all others the most brilliant, and best defined; because they were combined of the reverse spectrum of one colour, and of the direct spectrum of the other. Hence, in books printed with small types, or in the minute graduation of thermometers, or of clock-faces, which are to be seen at a distance, if the letters or figures are coloured with orange, and the ground with indigo; or the letters with red, and the ground with green; or any other lucid colour is used for the letters, the spectrum of which is similar to the colour of the ground; such letters will be seen much more distinctly, and with less confusion, than in black or white: for as the spectrum of the letter is the same colour with the ground on which they are seen, the unsteadiness of the eye in long attending to them will not produce coloured lines by the edges of the letters, which is the principal cause of their confusion. The beauty of colours lying in vicinity to each other, whose spectra are thus reciprocally similar to each colour, is owing to this greater ease that the eye experiences in beholding them distinctly; and it is probable, in the organ of hearing, a similar circumstance may constitute the pleasure of melody. Sir Isaac Newton observes, that gold and indigo were agreeable when viewed together; and thinks there may be some analogy between the sensations of light and sound. (Optics, Qu. 14.) In viewing the spectra of bright objects, as of an area of red silk of half an inch diameter on white paper, it is easy to magnify it to tenfold its size: for if, when the spectrum is formed, you still keep your eye fixed on the silk area, and remove it a few inches further from you, a green circle is seen round the red silk: for the angle now subtended by the silk is less than it was when the spectrum was formed, but that of the spectrum continues the same, and our imagination places them at the same distance. Thus when you view a spectrum on a sheet of white paper, if you approach the paper to the eye, you may diminish it to a point; and if the paper is made to recede from the eye, the spectrum will appear magnified in proportion to the distance. [Illustration: Fig. 5.] I was surprised, and agreeably amused, with the following experiment. I covered a paper about four inches square with yellow, and with a pen filled with a blue colour wrote upon the middle of it the word BANKS in capitals, as in Fig. 5, and sitting with my back to the sun, fixed my eyes for a minute exactly on the center of the letter N in the middle of the word; after closing my eyes, and shading them somewhat with my hand, the word was distinctly seen in the spectrum in yellow letters on a blue field; and then, on opening my eyes on a yellowish wall at twenty feet distance, the magnified name of BANKS appeared written on the wall in golden characters. _Conclusion._ It was observed by the learned M. Sauvage (Nosol. Method. Cl. VIII. Ord. i.) that the pulsations of the optic artery might be perceived by looking attentively on a white wall well illuminated. A kind of net-work, darker than the other parts of the wall, appears and vanishes alternately with every pulsation. This change of the colour of the wall he well ascribes to the compression of the retina by the diastole of the artery. The various colours produced in the eye by the pressure of the finger, or by a stroke on it, as mentioned by Sir Isaac Newton, seem likewise to originate from the unequal pressure on various parts of the retina. Now as Sir Isaac Newton has shewn, that all the different colours are reflected or transmitted by the laminæ of soap bubbles, or of air, according to their different thickness or thinness, is it not probable, that the effect of the activity of the retina may be to alter its thickness or thinness, so as better to adapt it to reflect or transmit the colours which stimulate it into action? May not muscular fibres exist in the retina for this purpose, which may be less minute than the locomotive muscles of microscopic animals? May not these muscular actions of the retina constitute the sensation of light and colours; and the voluntary repetitions of them, when the object is withdrawn, constitute our memory of them? And lastly, may not the laws of the sensations of light, here investigated, be applicable to all our other senses, and much contribute to elucidate many phenomena of animal bodies both in their healthy and diseased state; and thus render this investigation well worthy the attention of the physician, the metaphysician, and the natural philosopher? November 1, 1785. * * * * * Dum, Liber! astra petis volitans trepidantibus alis, Irruis immemori, parvula gutta, mari. Me quoque, me currente rotâ revolubilis ætas Volverit in tenebras,--i, Liber, ipse sequor. * * * * * INDEX TO THE SECTIONS OF PART FIRST. A. Abortion from fear, xxxix. 6. 5. Absorbent vessels, xxiii. 3. xxix. 1. ---- regurgitate their fluids, xxix. 2. ---- their valves, xxix. 2. ---- communicate with vena portarum, xxvii. 2. Absorption of solids, xxxiii. 3. 1. xxxvii. ---- of fluids in anasarca, xxxv. 1. 3. Accumulation of sensorial power, iv. 2. xii. 5. 2. Activity of system too great, cure of, xii. 6. ---- too small, cure of, xii. 7. Age, old, xii. 3. 1. xxxvii. 4. Ague-fit, xii. 7. 1. xxxii. 3. 4. xxxii. 9. ---- how cured by bark, xii. 3. 4. ---- periods, how occasioned, xii. 2. 3. xxxii. 3. 4. Ague cakes, xxxii. 7. xxxii. 9. Air, sense of fresh, xiv. 8. ---- injures ulcers, xxviii. 2. ---- injected into veins, xxxii. 5. Alcohol deleterious, xxx. 3. Alliterations, why agreeable, xxii. 2. Aloes in lessened doses, xii. 3. 1. American natives indolent, xxxi. 2. ---- narrow shouldered, xxxi. 1. Analogy intuitive, xvii. 3. 7. Animals less liable to madness, xxxiii. 1. ---- less liable to contagion, xxxiii. 1. ---- how to teach, xxii. 3. 2. ---- their similarity to each other, xxxix. 4. 8. ---- their changes after nativity, xxxix. 4. 8. ---- their changes before nativity, xxxix. 4. 8. ---- less liable to contagious diseases, why, xxxiii. 1. 5. ---- less liable to delirium and insanity, why, xxxiii. 1. 5. ---- easier to preserve than to reproduce, xxxvii. ---- food, distaste of, xxviii. 1. ---- appetency, xxxix. 4. 7. Antipathy, x. 2. 2. Aphthæ, xxviii. Apoplexy, xxxiv. 1. 7. ---- not from deficient irritation, xxxii. 2. 1. Appetites, xi. 2. 2. xiv. 8. Architecture, xxii. 2. xvi. 10. Arts, fine, xxii. 2. Asparagus, its smell in urine, xxix. Association defined, ii. 2. 11. iv. 7. v. 2. ---- associate motions, x. ---- stronger than irritative ones, xxiv. 2. 8. ---- formed before nativity, xi. 3. ---- with irritative ones, xxiv. 2. 8. ---- with retrograde ones, xxv. 7. xxv. 10. xxv. 15. ---- diseases from, xxxv. Asthma, xviii. 15. Attention, language of, xvi. 8. 6. Atrophy, xxviii. Aversion, origin of, xi. 2. 3. B. Balance ourselves by vision, xx. 1. Bandage increases absorption, xxxiii. 3. 2. Barrenness, xxxvi. 2. 3. Battement of sounds, xx. 7. Bath, cold. See Cold Bath. Beauty, sense of, xvi. 6. xxii. 2. Bile-ducts, xxx. ---- stones, xxx. 1. 3. ---- regurgitates into the blood, xxiv. 2. 7. ---- vomiting of, xxx. 1. 3. Birds of passage, xvi. 12. ---- nests of, xvi. 13. ---- colour of their eggs, xxxix. 5. Biting in pain, xxxiv. 1. 3. ---- of mad animals, xxxiv. 1. 3. Black spots on dice appear red, xl. 3. Bladder, communication of with the intestines, xxix. 3. ---- of fish, xxiv. 1. 4. Blood, transfusion of in nervous fevers, xxxii. 4. ---- deficiency of, xxxii. 2. and 4. ---- from the vena portarum into the intestines, xxvii. 2. ---- its momentum, xxxii. 5. 2. ---- momentum increased by venesection, xxxii. 5. 4. ---- drawn in nervous pains, xxxii. 5. 4. ---- its oxygenation, xxxviii. Breasts of men, xiv. 8. Breathing, how learnt, xvi. 4. Brutes differ from men, xi. 2. 3. xvi. 17. Brutes. See Animals. Buxton bath, why it feels warm, xii. 2. 1. xxxii. 3. 3. C. Capillary vessels are glands, xxvi. 1. Catalepsy, xxxiv. 1. 5. Catarrh from cold skin, xxxv. 1. 3. xxxv. 2. 3. ---- from thin caps in sleep, xviii. 15. Catenation of motions defined, ii. 2. 11. iv. 7. ---- cause of them, xvii. 1. 3. ---- described, xvii. ---- continue some time after their production, xvii. 1. 3. ---- voluntary ones dissevered in sleep, xvii. 1. 12. xvii. 3. 7. Cathartics, external, their operation, xxix. 7. 6. Causation, animal, defined, ii. 2. 11. iv. 7. Cause of causes, xxxix. 4. 8. Causes inert and efficient, xxxix. 8. 2. ---- active and passive, xxxix. 8. 3. ---- proximate and remote, xxxix. 8. 4. Chick in the egg, oxygenation of, xxxviii. 2. Child riding on a stick, xxxiv. 2. 6. Chilness after meals, xxi. 3. xxxv. 1. 1. Cholera, case of, xxv. 13. Circulation in the eye visible, xl. 10. 4. Cold in the head, xii. 6. 5. ---- perceived by the teeth, xxxii. 3. 1. xiv. 6. ---- air, uses of in fevers, xxxii. 3. 3. ---- feet, produces coryza, xxxv. 2. 3. xxxv. 1. 3. ---- bath, why it strengthens, xxxii. 3. 2. ---- short and cold breathing in it, xxxii. 3. 2. ---- produces a fever-fit, xxxii. 3. 2. ---- fit of fever the consequence of hot fit, xxxii. 9. 3. ---- bathing in pulmonary hæmorrhage, xxvii. 1. ---- fits of fever, xxxii. 4. xxxii. 9. xvii. 3. 3. Colours of animals, efficient cause of, xxxix. 5. 1. ---- of eggs from female imagination, xxxix. 5. 1. ---- of the choroid coat of the eye, xxxix. 5. 1. ---- of birds nests, xvi. 13. Comparing ideas, xv. 3. Consciousness, xv. 3. 4. ---- in dreams, xviii. 13. Consent of parts. See Sympathy. Consumption, its temperament, xxxi. 1. and 2. ---- of dark-eyed patients, xxvii. 2. ---- of light-eyed patients, xxviii. 2. ---- is contagious, xxxiii. 2. 7. Contagion, xii. 3. 6. xix. 9. xxxiii. 2. 6. and 8. xxii. 3. 3. ---- does not enter the blood, xxxiii. 2. 10. xxii. 3. 3. Contraction and attraction, iv. 1. ---- of fibres produces sensation, iv. 5. xii. 1. 6. ---- continues some time, xii. 1. 5. ---- alternates with relaxation, xii. 1. 3. Convulsion, xvii. 1. 8. xxxiv. 1. 1. and 4. iii. 5. 8. ---- of particular muscles, xvii. 1. 8. ---- periods of, xxxvi. 3. 9. Coryza. See Catarrh. Cough, nervous, periods of, xxxvi. 3. 9. Cramp, xviii. 15. xxxiv. 1. 7. Critical days from lunations, xxxvi. 4. D. Darkish room, why we see well in it, xii. 2. 1. Debility sensorial and stimulatory, xii. 2. 1. ---- direct and indirect of Dr. Brown, xii. 2. 1. xxxii. 3. 2. ---- See Weakness. ---- from drinking spirits, cure of, xii. 7. 8. ---- in fevers, cure of, xii. 7. 8. Deliberation, what, xxxiv. 1. Delirium, two kinds of, xxxiii. 1. 4. xxxiv. 2. 2. ---- cases of, iii. 5. 8. ---- prevented by dreams, xviii. 2. Desire, origin of, xi. 2. 3. Diabetes explained, xxix. 4. ---- with bloody urine, xxvii. 2. ---- in the night, xviii. 15. Diarrhoea, xxix. 4. Digestion, xxxiii. 1. xxxvii. ---- strengthened by emetics, xxxv. 1. 3. ---- strengthened by regular hours, why, xxxvi. 2. 1. Digitalis, use of in dropsy, xxix. 5. 2. Distention acts as a stimulus, xxxii. 4. ---- See Extension. Distinguishing, xv. 3. Diurnal circle of actions, xxv. 4. Doubting, xv. 3. Dreams, viii. 1. 2. xiv. 2. 5. ---- their inconsistency, xviii. 17. ---- no surprise in them, xviii. 17. ---- much novelty of combination, xviii. 9. Dropsies explained, xxix. 5. 1. Dropsy cured by insanity, xxxiv. 2. 7. ---- cure of, xxix. 5. 2. Drunkards weak till next day, xvii. 1. 7. ---- stammer, and stagger, and weep, xii. 4. 1. xxi. 4. ---- see objects double, why, xxi. 7. ---- become delirious, sleepy, stupid, xxi. 5. Drunkenness. See Intoxication, xxi. ---- diminished by attention, xxi. 8. Dyspnoea in cold bath, xxxii. 3. 2. E. Ear, a good one, xvi. 10. ---- noise in, xx. 7. Eggs of frogs, fish, fowl, xxxix. 2. ---- of birds, why spotted, xxxix. 5. ---- with double yolk, xxxix. 4. 4. Electricity, xii. 1. xiv. 9. ---- jaundice cured by it, xxx. 1. 2. Embryon produced by the male, xxxix. 2. ---- consists of a living fibre, xxxix. 4. ---- absorbs nutriment, receives oxygen, xxxix. 1. ---- its actions and sensations, xvi. 2. Emetic. See Vomiting. Emotions, xi. 2. 2. Ennui, or tædium vitæ, xxxiv. 2. 3. xxxiii. 1. 1. xxxix. 6. Epileptic fits explained, xxxiv. 1. 4. xxvii. 2. ---- in sleep, why, xviii. 14. & 15. Equinoxial lunations, xxxii. 6. Excitability perpetually varies, xii. 1. 7. ---- synonymous to quantity of sensorial power, xii. 1. 7. Exercise, its use, xxxii. 5. 3. Exertion of sensorial power defined, xii. 2. 1. Existence in space, xiv. 2. 5. Extension, sense of, xiv. 7. Eyes become black in some epilepsies, xxvii. 2. F. Face, flushing of after dinner, xxxv. 1. 1. ---- why first affected in small-pox, xxxv. 1. 1. ---- red from inflamed liver, xxxv. 2. 2. Fainting fits, xii. 7. 1. xiv. 7. Fear, language of, xvi. 8. 1. ---- a cause of fever, xxxii. 8. ---- cause of, xvii. 3. 7. Fetus. See Embryon, xvi. 2. xxxix. 1. Fevers, irritative, xxxii. 1. ---- intermittent, xxxii. 1. xxxii. 3. ---- sensitive, xxxiii. 1. ---- not an effort of nature for relief, xxxii. 10. ---- paroxysms of, xii. 7. 1. xii. 2. 3. xii. 3. 5. ---- why some intermit and not others, xxxvi. 1. ---- cold fits of, xxxii. 4. xxxii. 9. xvii. 3. 3. ---- periods of, xxxvi. 3. ---- have solar or lunar periods, xxxii. 6. ---- source of the symptoms of, xxxii. 1. ---- prostration of strength in, xii. 4. 1. xxxii. 3. 2. ---- cure of, xii. 6. 1. ---- how cured by the bark, xii. 3. 4. ---- cured by increased volition, xii. 2. 4. xxxiv. 2. 8. ---- best quantity of stimulus in, xii. 7. 8. Fibres. See Muscles. Fibres, their mobility, xii. 1. 7. xii. 1. 1. ---- contractions of, vi. xii. 1. 1. ---- four classes of their motions, vi. ---- their motions distinguished from sensorial ones, v. 3. Figure, xiv. 2. 2. iii. 1. Fish, their knowledge, xvi. 14. Foxglove, its use in dropsies, xxix. 5. 2. ---- overdose of, xxv. 17. Free-will, xv. 3. 7. G. Gall-stone, xxv. 17. ---- See Bile-stones. Generation, xxxiii. 1. xxxix. Gills of fish, xxxviii. 2. Glands, xxiii. 2. ---- conglobate glands, xxiii. 3. ---- have their peculiar stimulus, xi. 1. ---- their senses, xiv. 9. xxxix. 6. ---- invert their motions, xxv. 7. ---- increase their motions, xxv. 7. Golden rule for exhibiting wine, xii. 7. 8. ---- for leaving off wine, xii. 7. 8. Gout from inflamed liver, xxxv. 2. 2. xviii. 16. xxiv. 2. 8. ---- in the stomach, xxiv. 2. 8. xxv. 17. ---- why it returns after evacuations, xxxii. 4. ---- owing to vinous spirit only, xxi. 10. ---- periods of, xxxvi. 3. 6. Grinning in pain, xxxiv. 1. 3. Gyration on one foot, xx. 5. and 6. H. Habit defined, ii. 2. 11. iv. 7. Hæmorrhages, periods of, xxxvi. 3. 11. ---- from paralysis of veins, xxvii. 1. and 2. Hair and nails, xxxix. 3. 2. ---- colour of, xxxix. 5. 1. Harmony, xxii. 2. Head-achs, xxxv. 2. 1. Hearing, xiv. 4. Heat, sense of, xiv. 6. xxxii. 3. 1. ---- produced by the glands, xxxii. 3. ---- external and internal, xxxii. 3. 1. ---- atmosphere of heat, xxxii. 3. 1. ---- increases during sleep, xviii. 15. Hemicrania, xxxv. 2. 1. ---- from decaying teeth, xxxv. 2. 1. Hepatitis, cause of, xxxv. 2. 3. Hereditary diseases, xxxix. 7. 6. Hermaphrodite insects, xxxix. 5. Herpes, xxviii. 2. ---- from inflamed kidney, xxxv. 2. 2. Hilarity from diurnal fever, xxxvi. 3. 1. Hunger, sense of, xiv. 8. Hydrophobia, xxii. 3. 3. Hypochondriacism, xxxiii. 1. 1. xxxiv. 2. 3. I. Ideas defined, ii. 2. 7. ---- are motions of the organs of sense, iii. 4. xviii. 5. xviii. 10. xviii. 6. ---- analogous to muscular motions, iii. 5. ---- continue some time, xx. 6. ---- new ones cannot be invented, iii. 6. 1. ---- abstracted ones, iii. 6. 4. ---- inconsistent trains of, xviii. 17. ---- perish with the organ of sense, iii. 4. 4. ---- painful from inflammation of the organ, iii. 5. 5. ---- irritative ones, vii. 1. 4. vii. 3. 2. xv. 2. xx. 7. ---- of resemblance, contiguity, causation, viii. 3. 2. x. 3. 3. ---- resemble the figure and other properties of bodies, xiv. 2. 2. ---- received in tribes, xv. 1. ---- of the same sense easier combined, xv. 1. 1. ---- of reflection, xv. 1. 6. ii. 2. 12. Ideal presence, xv. 1. 7. Identity, xv. 3. 5. xviii. 13. Iliac passion, xxv. 15. Imagination, viii. 1. 2. xv. 1. 7. xv. 2. 2. ---- of the male forms the sex, xxxix. 6. Imitation, origin of, xii. 3. 3. xxxix. 5. xxii. 3. xvi. 7. Immaterial beings, xiv. 1. xiv. 2. 4. Impediment of speech, xvii. 1. 10. xvii. 2. 10. Infection. See Contagion. Inflammation, xii. 2. 3. xxxiii. 2. 2. ---- great vascular exertion in, xii. 2. 1. ---- not from pains from defect of stimulus, xxxiii. 2. 3. ---- of parts previously insensible, xii. 3. 7. ---- often distant from its cause, xxiv. 2. 8. ---- observes solar days, xxxii. 6. ---- of the eye, xxxiii. 3. 1. ---- of the bowels prevented by their continued action in sleep, xviii. 2. Inoculation with blood, xxxiii. 2. 10. Insane people, their great strength, xii. 2. 1. Insanity (see Madness) pleasurable one, xxxiv. 2. 6. Insects, their knowledge, xvi. 15. and 16. ---- in the heads of calves, xxxix. 1. ---- class of, xxxix. 4. 8. Instinctive actions defined, xvi. 1. Intestines, xxv. 3. Intoxication relieves pain, why, xxi. 3. ---- from food after fatigue, xxi. 2. ---- diseases from it, xxi. 10. ---- See Drunkenness. Intuitive analogy, xvii. 3. 7. Invention, xv. 3. 3. Irritability increases during sleep, xviii. 15. Itching, xiv. 9. J. Jaundice from paralysis of the liver, xxx. 1. 2. ---- cured by electricity, xxx. 1. 2. Jaw-locked, xxxiv. 1. 5. Judgment, xv. 3. K. Knowledge of various animals, xvi. 11. L. Lachrymal sack, xvi. 8. xxiv. 2. 2. and 7. Lacteals, paralysis of, xxviii. ---- See Absorbents. Lady playing on the harpsichord, xvii. 2. ---- distressed for her dying bird, xvii. 2. 10. Language, natural, its origin, xvi. 7. & 8. ---- of various passions described, xvi. 8. ---- artificial, of various animals, xvi. 9. ---- theory of, xxxix. 8. 3. Lapping of puppies, xvi. 4. Laughter explained, xxxiv. 1. 4. ---- from tickling, xvii. 3. 5. xxxiv. 1. 4. ---- from frivolous ideas, xxxiv. 1. 4. xviii. 12. Life, long, art of producing, xxxvii. Light has no momentum, iii. 3. 1. Liquor amnii, xvi. 2. xxxviii. 2. ---- is nutritious, xxxviii. 3. ---- frozen, xxxviii. 3. Liver, paralysis of, xxx. 1. 4. ---- large of geese, xxx. 1. 6. Love, sentimental, its origin, xvi. 6. ---- animal, xiv. 8. xvi. 5. Lunar periods affect diseases, xxxii. 6. Lust, xiv. 8. xvi. 5. Lymphatics, paralysis of, xxviii. ---- See Absorbents. M. Mad-dog, bite of, xxii. 3. 3. Madness, xxxiv. 2. 1. xii. 2. 1. Magnetism, xii. 1. 1. Magnifying objects, new way of, xl. 10. 5. Male animals have teats, xxxix. 4. 8. ---- pigeons give milk, xxxix. 4. 8. Man distinguished from brutes, xi. 2. 3. xvi. 17. Material world, xiv. 1. xiv. 2. 5. xviii. 7. Matter, penetrability of, xiv. 2. 3. ---- purulent, xxxiii. 2. 4. Measles, xxxiii. 2. 9. Membranes, xxvi. 2. Memory defined, ii. 2. 10. xv. 1. 7. xv. 3. Menstruation by lunar periods, xxxii. 6. Miscarriage from fear, xxxix. 6. 5. Mobility of fibres, xii. 1. 7. Momentum of the blood, xxxii. 5. 2. ---- sometimes increased by venesection, xxxii. 5. 4. Monsters, xxxix. 4. 4. and 5. 2. ---- without heads, xxxviii. 3. Moon and sun, their influence, xxxii. 6. Mortification, xxxiii. 3. 3. Motion is either cause or effect, i. xiv. 2. 2. ---- primary and secondary, i. ---- animal, i. iii. 1. ---- propensity to, xxii. 1. ---- animal, continue some time after their production, xvii. 1. 3. ---- defined, a variation of figure, iii. 1. xiv. 2. 2. xxxix. 8. Mucus, experiments on, xxvi. 1. ---- secretion of, xxvi. 2. Mules, xxxix. 4. 5. and 6. xxxix. 5. 2. Mule plants, xxxix. 2. Muscæ volitantes, xl. 2. Muscles constitute an organ of sense, xiv. 7. ii. 2. 4. ---- stimulated by extension, xi. 1. xiv. 7. ---- contract by spirit of animation, xii. 1. 1. and 3. Music, xvi. 10. xxii. 2. Musical time, why agreeable, xii. 3. 3. N. Nausea, xxv. 6. Nerves and brain, ii. 2. 3. ---- extremities of form the whole system, xxxvii. 3. ---- are not changed with age, xxxvii. 4. Nervous pains defined, xxxiv. 1. 1. Number defined, xiv. 2. 2. Nutriment for the embryon, xxxix. 5. 2. Nutrition owing to stimulus, xxxvii. 3. ---- by animal selection, xxxvii. 3. ---- when the fibres are elongated, xxxvii. 3. ---- like inflammation, xxxvii. 3. O. Objects long viewed become faint, iii. 3. 2. Ocular spectra, xl. Oil externally in diabætes, xxix. 4. Old age from inirritability, xxxvii. Opium is stimulant, xxxii. 2. 2. ---- promotes absorption after evacuation, xxxiii. 3. 1. ---- in increasing doses, xii. 3. 1. Organs of sense, ii. 2. 5. and 6. Organs when destroyed cease to produce ideas, iii. 4. 4. Organic particles of Buffon, xxxvii. 3. xxxix. 3. 3. Organ-pipes, xx. 7. Oxygenation of the blood, xxxviii. P. Pain from excess and defect of motion, iv. 5. xii. 5. 3. xxxiv. 1. xxxv. 2. 1. ---- not felt during exertion, xxxiv. 1. 2. ---- from greater contraction of fibres, xii. 1. 6. ---- from accumulation of sensorial power, xii. 5. 3. ---- from light, pressure, heat, caustics, xiv. 9. ---- in epilepsy, xxxv. 2. 1. ---- distant from its cause, xxiv. 2. 8. ---- from stone in the bladder, xxxv. 2. 1. ---- of head and back from defect, xxxii. 3. ---- from a gall-stone, xxxv. 2. 1. xxv. 17. ---- of the stomach in gout, xxv. 17. ---- of shoulder in hepatitis, xxxv. 2. 4. ---- produces volition, iv. 6. Paleness in cold fit, xxxii. 3. 2. Palsies explained, xxxiv. 1. 7. Paralytic limbs stretch from irritation, vii. 1. 3. ---- patients move their sound limb much, xii. 5. 1. Paralysis from great exertion, xii. 4. 6. ---- from less exertion, xii. 5. 6. ---- of the lacteals, xxviii. ---- of the liver, xxx. 1. 4. ---- of the right arm, why, xxxiv. 1. 7. ---- of the veins, xxvii. 2. Particles of matter will not approach, xii. 1. 1. Passions, xi. 2. 2. ---- connate, xvi. 1. Pecking of chickens, xvi. 4. Perception defined, ii. 2. 8. xv. 3. 1. Periods of agues, how formed, xxxii. 3. 4. ---- of diseases, xxxvi. ---- of natural actions and of diseased actions, xxxvi. Perspiration in fever-fits, xxxii. 9. See Sweat. Petechiæ, xxvii. 2. Pigeons secrete milk in their stomachs, xxxix. 4. 8. Piles, xxvii. 2. Placenta a pulmonary organ, xxxviii. 2. Pleasure of life, xxxiii. 1. xxxix. 5. ---- from greater fibrous contractions, xii. 1. 6. ---- what kind causes laughter, xxxiv. 1. 4. ---- what kind causes sleep, xxxiv. 1. 4. Pleurisy, periods of, xxxvi. 3. 7. ---- cause of, xxxv. 2. 3. Prometheus, story of, xxx. 3. Prostration of strength in fevers, xii. 4. 1. Pupils of the eyes large, xxxi. 1. Pulse quick in fevers with debility, xii. 1. 4. xii. 5. 4. xxxii. 2. 1. ---- in fevers with strength, xxxii. 2. ---- from defect of blood, xxxii. 2. 3. xii. 1. 4. ---- weak from emetics, xxv. 17. Q. Quack advertisements injurious. Preface. Quadrupeds have no sanguiferous lochia, xxxviii. 2. ---- have nothing similar to the yolk of egg, xxxix. 1. R. Rhaphania, periods of, xxxvi. 3. 9. Reason, ix. 1. 2. xv. 3. Reasoning, xv. 3. Recollection, ii. 2. 10. ix. 1. 2. xv. 2. 3. Relaxation and bracing, xxxii. 3. 2. Repetition, why agreeable, xii. 3. 3. xxii. 2. Respiration affected by attention, xxxvi. 2. 1. Restlessness in fevers, xxxiv. 1. 2. Retrograde motions, xii. 5. 5. xxv. 6. xxix. 11. ---- of the stomach, xxv. 6. ---- of the skin, xxv. 9. ---- of fluids, how distinguished, xxix. 8. ---- how caused, xxix. 11. 5. ---- vegetable motions, xxix. 9. Retina is fibrous, iii. 2. xl. 1. ---- is active in vision, iii. 3. xl. 1. ---- excited into spasmodic motions, xl. 7. ---- is sensible during sleep, xviii. 5. xix. 8. Reverie, xix. 1. xxxiv. 3. ---- case of a sleep-walker, xix. 2. ---- is an epileptic disease, xix. 9. Rhymes in poetry, why agreeable, xxii. 2. Rheumatism, three kinds of, xxvi. 3. Rocking young children, xxi. 3. Ruminating animals, xxv. 1. S. Saliva produced by mercury, xxiv. 1. ---- by food, xxiv. 1. 1. ---- by ideas, xxiv. 1. 2. and 5. ---- by disordered volition, xxiv. 1. 7. Schirrous tumours revive, xii. 2. 2. Screaming in pain, xxxiv. 1. 3. Scrophula, its temperament, xxxi. 1. ---- xxviii. 2. xxxix. 4. 5. Scurvy of the lungs, xxvii. 2. Sea-sickness, xx. 4. ---- stopped by attention, xx. 5. Secretion, xxxiii. 1. xxxvii. ---- increased during sleep, xviii. 16. Seeds require oxygenation, xxxviii. 2. Sensation defined, ii. 2. 9. v. 2. xxxix. 8. 4. ---- diseases of, xxxiii. ---- from fibrous contractions, iv. 5. xii. 1. 6. ---- in an amputated limb, iii. 6. 3. ---- affects the whole sensorium, xi. 2. ---- produces volition, iv. 6. Sensibility increases during sleep, xviii. 15. Sensitive motions, viii. xxxiii. 2. xxxiv. 1. ---- fevers of two kinds, xxxiii. 1. 2. ---- ideas, xv. 2. 2. Sensorium defined, ii. 2. 1. Senses correct one another, xviii. 7. ---- distinguished from appetites, xxxiv. 1. 1. Sensorial power. See Spirit of Animation. ---- great expence of in the vital motions, xxxii. 3. 2. ---- two kinds of excited in sensitive fevers, xxxiii. 1. 3. ---- powers defined, v. 1. ---- motions distinguished from fibrous motions, v. 3. ---- not much, accumulated in sleep, xviii. 2. ---- powers, accumulation of, xii. 5. 1. ---- exhaustion of, xii. 4. 1. ---- wasted below natural in hot fits, xxxii. 9. 3. ---- less exertion of produces pain, xii. 5. 3. ---- less quantity of it, xii. 5. 4. Sensual motions distinguished from muscular, ii. 2. 7. Sex owing to the imagination of the father, xxxix. 7. 6. xxxix. 6. 3. xxxix. 6. 7. xxxix. 5. Shingles from inflamed kidney, xxxv. 2. 2. Shoulders broad, xxxi. 1. xxxix. 7. 6. Shuddering from cold, xxxiv. 1. 1. and 2. Sight, its accuracy in men, xvi. 6. Skin, skurf on it, xxvi. 1. Sleep suspends volition, xviii. 1. ---- defined, xviii. 21. ---- remote causes, xviii. 20. ---- sensation continues in it, xviii. 2. ---- from food, xxi. 1. ---- from rocking, uniform sounds, xxi. 1. ---- from wine and opium, xxi. 3. ---- why it invigorates, xii. 5. 1. ---- pulse slower and fuller, xxxii. 2. 2. ---- interrupted, xxvii. 2. ---- from breathing less oxygene, xviii. 20. ---- from being whirled on a millstone, xviii. 20. ---- from application of cold, xviii. 20. ---- induced by regular hours, xxxvi. 2. 2. Sleeping animals, xii. 2. 2. Sleep-walkers. See Reverie, xix. 1. Small-pox, xxxiii. 2. 6. xxxix. 6. 1. ---- eruption first on the face, why, xxxv. 1. 1. xxxiii. 2. 10. ---- the blood will not infect, xxxiii. 2. 10. ---- obeys lunations, xxxvi. 4. Smell, xiv. 5. xvi. 5. Smiling, origin of, xvi. 8. 4. Solidity, xiv. 2. 1. Somnambulation. See Reverie, xix. 1. Space, xiv. 2. 2. Spasm, doctrine of, xxxii. 10. Spectra, ocular, xl. ---- mistaken for spectres, xl. 2. ---- vary from long inspection, iii. 3. 5. Spirit of animation. See Sensorial Power. ---- of animation causes fibrous contraction, iv. 2. ii. 2. 1. xiv. 2. 4. ---- possesses solidity, figure, and other properties of matter, xiv. 2. 4. Spirits and angels, xiv. 2. 4. Stammering explained, xvii. 1. 10. xvii. 2. 10. Stimulus defined, ii. 2. 13. iv. 4. xii. 2. 1. ---- of various kinds, xi. 1. ---- with lessened effect, xii. 3. 1. ---- with greater effect, xii. 3. 3. ---- ceases to produce sensation, xii. 3. 6. Stomach and intestines, xxv. ---- inverted by great stimulus, xxv. 6. ---- its actions decreased in vomiting, xxxv. 1. 3. ---- a blow on it occasions death, xxv. 17. Stools black, xxvii. 2. Strangury, xxxv. 2. 1. Sucking before nativity, xvi. 4. Suckling children, sense of, xiv. 8. Suggestion defined, ii. 2. 10. xv. 2. 4. Sun and moon, their influence, xxxii. 6. Surprise, xvii. 3. 7. xviii. 17. Suspicion attends madness, xxxiv. 2. 4. Swallowing, act of, xxv. 1. xvi. 4. Sweat, cold, xxv. 9. xxix. 6. ---- in hot fit of fever, xxxii. 9. ---- in a morning, why, xviii. 15. Sweaty hands cured by lime, xxix. 4. 9. Swinging and rocking, why agreeable, xxi. 3. Sympathy, xxxv. 1. Syncope, xii. 7. 1. xxxiv. 1. 6. T. Tædium vitæ. See Ennui. Tape-worm, xxxix. 2. 3. Taste, sense of, xiv. 5. Tears, secretion of, xxiv. ---- from grief, xvi. 8. 2. ---- from tender pleasure, xvi. 8. 3. ---- from stimulus of nasal duct, xvi. 8. xxiv. 2. 4. ---- by volition, xxiv. 2. 6. Teeth decaying cause headachs, xxxv. 2. 1. Temperaments, xxxi. Theory of medicine, wanted. Preface. Thirst, sense of, xiv. 8. ---- why in dropsies, xxix. 5. Tickle themselves, children cannot, xvii. 3. 5. Tickling, xiv. 9. Time, xiv. 2. 2. xviii. 12. ---- lapse of, xv. 3. 6. ---- poetic and musical, why agreeable, xxii. 2. ---- dramatic, xviii. 12. Tooth-edge, xvi. 10. iii. 4. 3. xxii. 3. 3. Touch, sense of, xiv. 2. 1. ---- liable to vertigo, xxi. 9. ---- of various animals, xvi. 6. Trains of motions inverted, xii. 5. 5. Transfusion of blood in nervous fever, xxxii. 4. Translations of matter, xxix. 7. Typhus, best quantity of stimulus in, xii. 7. 8. ---- periods of observe lunar days, xxxii. 6. U. Ulcers, art of healing, xxxiii. 3. 2. ---- of the lungs, why difficult to heal, xxviii. 2. Uniformity in the fine arts, why agreeable, xxii. 2. Urine pale in intoxication, xxi. 6. ---- paucity of in anasarca, why, xxix. 5. ---- its passage from intestines to bladder, xxix. 3. ---- copious during sleep, xviii. 15. V. Variation, perpetual, of irritability, xii. 2. 1. Vegetable buds are inferior animals, xiii. 1. ---- exactly resemble their parents, xxxix. ---- possess sensation and volition, xiii. 2. ---- have associate and retrograde motions, xiii. 4. xxix. 9. ---- their anthers and stigmas are alive, xiii. 5. ---- have organs of sense and ideas, xiii. 5. ---- contend for light and air, xxxix. 4. 8. ---- duplicature of their flowers, xxxix. 4. 4. Veins are absorbents, xxvii. 1. ---- paralysis of, xxvii. 1. Venereal orgasm of brutes, xxxii. 6. Venesection in nervous pains, xxxii. 5. 4. Verbs of three kinds, xv. 3. 4. Verses, their measure, xxii. 2. Vertigo, xx. ---- defined, xx. 11. ---- in looking from a tower, xx. 1. ---- in a ship at sea, xx. 4. ---- of all the senses, xxi. 9. ---- by intoxication, xxxv. 1. 2. Vibratory motions perceived after sailing, xx. 5. xx. 10. Vinegar makes the lips pale, xxvii. 1. Vis medicatrix of nature, xxxix. 4. 7. Vision, sense of, xiv. 3. Volition defined, v. 2. xxxiv. 1. ---- affects the whole sensorium, xi. 2. ---- diseases of, xxxiv. Voluntarity, xi. 2. 4. Voluntary motions, ix. xxxiv. 1. Voluntary ideas, xv. 2. 3. ---- criterion of, xi. 2. 3. xxxiv. 1. Vomiting from vertigo, xx. 8. ---- from drunkenness, xx. 8. xxi. 6. ---- by intervals, xxv. 8. ---- by voluntary efforts, xxv. 6. ---- of two kinds, xxxv. 1. 3. ---- in cold fit of fever, xxxii. 9. 1. ---- stopped by quicksilver, xxv. 16. ---- weakens the pulse, xxv. 17. W. Waking, how, xviii. 14. Walking, how learnt, xvi. 3. Warmth in sleep, why, xviii. 15. Weakness defined, xii. 1. 3. xii. 2. 1. xxxii. 3. 2. ---- cure of, xii. 7. 8. ---- See Debility. Wit producing laughter, xxxiv. 1. 4. World generated, xxxix. 4. 8. * * * * * END OF THE FIRST VOLUME. 
5694	----	The Harvard Classics Volume 38 Scientific Papers (Physiology, Medicine, Surgery, Geology) CONTENTS THE OATH OF HIPPOCRATES THE LAW OF HIPPOCRATES JOURNEYS IN DIVERSE PLACES ... AMBROISE PARE TRANSLATED BY STEPHEN PAGET ON THE MOTION OF THE HEART AND BLOOD IN ANIMALS WILLIAM HARVEY. . . TRANSLATED BY ROBERT WILLIS THE THREE ORIGINAL PUBLICATIONS ON VACCINATION AGAINST SMALLPOX . ... .. EDWARD JENNER THE CONTAGIOUSNESS OF PUERPERAL FEVER O. W. HOLMES ON THE ANTISEPTIC PRINCIPLE OF THE PRACTICE OF SURGERY LORD LISTER THE PHYSIOLOGICAL THEORY OF FERMENTATION LOUIS PASTEUR TRANSLATED BY F. FAULKNER AND D. C. ROBB (Revised) THE GERM THEORY AND ITS APPLICATIONS TO MEDICINE AND SURGERY (Revised) . ... .. LOUIS PASTEUR TRANSLATED BY H. C. ERNST ON THE EXTENSION OF THE GERM THEORY TO THE ETIOLOGY OF CERTAIN COMMON DISEASES (Revised) LOUIS PASTEUR TRANSLATED BY H. C. ERNST PREJUDICES WHICH HAVE RETARDED THE PROGRESS OF GEOLOGY. ... . ... .. SIR CHARLES LYELL UNIFORMITY IN THE SERIES OF PAST CHANGES IN THE ANIMATE AND INANIMATE WORLD SIR CHARLES LYELL INTRODUCTORY NOTE Hippocrates, the celebrated Greek physician, was a contemporary of the historian Herodotus. He was born in the island of Cos between 470 and 460 B. C., and belonged to the family that claimed descent from the mythical AEsculapius, son of Apollo. There was already a long medical tradition in Greece before his day, and this he is supposed to have inherited chiefly through his predecessor Herodicus; and he enlarged his education by extensive travel. He is said, though the evidence is unsatisfactory, to have taken part in the efforts to check the great plague which devastated Athens at the beginning of the Peloponnesian war. He died at Larissa between 380 and 360 B. C. The works attributed to Hippocrates are the earliest extant Greek medical writings, but very many of them are certainly not his. Some five or six, however, are generally granted to be genuine, and among these is the famous "Oath." This interesting document shows that in his time physicians were already organized into a corporation or guild, with regulations for the training of disciples, and with an esprit de corps and a professional ideal which, with slight exceptions, can hardly yet be regarded as out of date. One saying occurring in the words of Hippocrates has achieved universal currency, though few who quote it to-day are aware that it originally referred to the art of the physician. It is the first of his "Aphorisms": "Life is short, and the Art long; the occasion fleeting; experience fallacious, and judgment difficult. The physician must not only be prepared to do what is right himself, but also to make the patient, the attendants, and externals cooperate." THE OATH OF HIPPOCRATES I swear by Apollo the physician and AEsculapius, and Health, and All-heal, and all the gods and goddesses, that, according to my ability and judgment, I will keep this Oath and this stipulation --to reckon him who taught me this Art equally dear to me as my parents, to share my substance with him, and relieve his necessities if required; to look upon his offspring in the same footing as my own brothers, and to teach them this art, if they shall wish to learn it, without fee or stipulation; and that by precept, lecture, and every other mode of instruction, I will impart a knowledge of the Art to my own sons, and those of my teachers, and to disciples bound by a stipulation and oath according to the law of medicine, but to none others. I will follow that system of regimen which, according to my ability and judgment, I consider for the benefit of my patients, and abstain from whatever is deleterious and mischievous. I will give no deadly medicine to any one if asked, nor suggest any such counsel; and in like manner I will not give to a woman a pessary to produce abortion. With purity and with holiness I will pass my life and practice my Art. I will not cut persons labouring under the stone, but will leave this to be done by men who are practitioners of this work. Into whatever houses I enter, I will go into them for the benefit of the sick, and will abstain from every voluntary act of mischief and corruption; and, further, from the seduction of females or males, of freemen and slaves. Whatever, in connection with my professional practice, or not in connection with it, I see or hear, in the life of men, which ought not to be spoken of abroad, I will not divulge, as reckoning that all such should be kept secret. While I continue to keep this Oath unviolated, may it be granted to me to enjoy life and the practice of the art, respected by all men, in all times. But should I trespass and violate this Oath, may the reverse be my lot. THE LAW OF HIPPOCRATES Medicine is of all the arts the most noble; but, owing to the ignorance of those who practice it, and of those who, inconsiderately, form a judgment of them, it is at present far behind all the other arts. Their mistake appears to me to arise principally from this, that in the cities there is no punishment connected with the practice of medicine (and with it alone) except disgrace, and that does not hurt those who are familiar with it. Such persons are like the figures which are introduced in tragedies, for as they have the shape, and dress, and personal appearance of an actor, but are not actors, so also physicians are many in title but very few in reality. 2. Whoever is to acquire a competent knowledge of medicine, ought to be possessed of the following advantages: a natural disposition; instruction; a favorable position for the study; early tuition; love of labour; leisure. First of all, a natural talent is required; for, when Nature leads the way to what is most excellent, instruction in the art takes place, which the student must try to appropriate to himself by reflection, becoming an early pupil in a place well adapted for instruction. He must also bring to the task a love of labour and perseverance, so that the instruction taking root may bring forth proper and abundant fruits. 3. Instruction in medicine is like the culture of the productions of the earth. For our natural disposition, is, as it were, the soil; the tenets of our teacher are, as it were, the seed; instruction in youth is like the planting of the seed in the ground at the proper season; the place where the instruction is communicated is like the food imparted to vegetables by the atmosphere; diligent study is like the cultivation of the fields; and it is time which imparts strength to all things and brings them to maturity. 4. Having brought all these requisites to the study of medicine, and having acquired a true knowledge of it, we shall thus, in travelling through the cities, be esteemed physicians not only in name but in reality. But inexperience is a bad treasure, and a bad fund to those who possess it, whether in opinion or reality, being devoid of self-reliance and contentedness, and the nurse both of timidity and audacity. For timidity betrays a want of powers, and audacity a lack of skill. They are, indeed, two things, knowledge and opinion, of which the one makes its possessor really to know, the other to be ignorant. 5. Those things which are sacred, are to be imparted only to sacred persons; and it is not lawful to impart them to the profane until they have been initiated in the mysteries of the science. JOURNEYS IN DIVERSE PLACES BY AMBROISE PARE TRANSLATED BY STEPHEN PAGET Ambroise Pare was born in the village of Bourg-Hersent, near Laval, in Maine, France, about 1510. He was trained as a barber- surgeon at a time when a barber-surgeon was inferior to a surgeon and the professions of surgeon and physician were kept apart by the law of the Church that forbade a physician to shed blood. Under whom he served his apprenticeship is unknown, but by 1533 he was in Paris, where he received an appointment as house surgeon at the Hotel Dieu. After three or four years of valuable experience in this hospital, he set up in private practise in Paris, but for the next thirty years he was there only in the intervals of peace; the rest of the time he followed the army. He became a master barber-surgeon in 1541. In Pare's time the armies of Europe were not regularly equipped with a medical service. The great nobles were accompanied by their private physicians; the common soldiers doctored themselves, or used the services of barber-surgeons and quacks who accompanied the army as adventurers. "When Pare joined the army" says Paget, "he went simply as a follower of Colonel Montejan, having neither rank, recognition, nor regular payment. His fees make up in romance for their irregularity: a cask of wine, fifty double ducats and a horse, a diamond, a collection of crowns and half-crowns from the ranks, other honorable presents and of great value'; from the King himself, three hundred crowns, and a promise he would never let him be in want; another diamond, this time from the finger of a duchess: and a soldier once offered a bag of gold to him." When Pare was a man of seventy, the Dean of the Faculty of Medicine in Paris made an attack on him on account of his use of the ligature instead of cauterizing after amputation. In answer, Pare appealed to his successful experience, and narrated the "Journeys in Diverse Places" here printed. This entertaining volume gives a vivid picture, not merely of the condition of surgery in the sixteenth century, but of the military life of the time; and reveals incidentally a personality of remarkable vigor and charm. Pare's own achievements are recorded with modest satisfaction: "I dressed him, and God healed him," is the refrain. Pare died in Paris in December, 1590. JOURNEYS IN DIVERSE PLACES [Footnote: The present translation is taken from Mr. Stephen Paget's "Ambroise Pare and His Times" by arrangement with Messrs. G. P. Putnam's Sons.] 1537-1569 THE JOURNEY TO TURIN. 1537 I will here shew my readers the towns and places where I found a way to learn the art of surgery: for the better instruction of the young surgeon. And first, in the year 1536, the great King Francis sent a large army to Turin, to recover the towns and castles that had been taken by the Marquis du Guast, Lieutenant-General of the Emperor. M. the Constable, then Grand Master, was Lieutenant-General of the army, and M. de Montejan was Colonel-General of the infantry, whose surgeon I was at this time. A great part of the army being come to the Pass of Suze, we found the enemy occupying it; and they had made forts and trenches, so that we had to fight to dislodge them and drive them out. And there were many killed and wounded on both sides,--but the enemy were forced to give way and retreat into the castle, which was captured, part of it, by Captain Le Rat, who was posted on a little hill with some of his soldiers, whence they fired straight on the enemy. He received an arquebus-shot in his right ankle, and fell to the ground at once, and then said, "Now they have got the Rat." I dressed him, and God healed him. We entered pell-mell into the city, and passed over the dead bodies, and some not yet dead, hearing them cry under our horses' feet; and they made my heart ache to hear them. And truly I repented I had left Paris to see such a pitiful spectacle. Being come into the city, I entered into a stable, thinking to lodge my own and my man's horse, and found four dead soldiers, and three propped against the wall, their features all changed, and they neither saw, heard, nor spake, and their clothes were still smouldering where the gunpowder had burned them. As I was looking at them with pity, there came an old soldier who asked me if there were any way to cure them; I said no. And then he went up to them and cut their throats, gently, and without ill will toward them. Seeing this great cruelty, I told him he was a villain: he answered he prayed God, when he should be in such a plight, he might find someone to do the same for him; that he should not linger in misery. To come back to my story, the enemy were called on to surrender, which they did, and left the city with only their lives saved, and the white stick in their hands; and most of them went off to the Chateau de Villane, where about two hundred Spaniards were stationed. M. the Constable would not leave these behind him, wishing to clear the road for our own men. The castle is seated on a small hill; which gave great confidence to those within, that we could not bring our artillery to bear upon them. They were summoned to surrender, or they would be cut in pieces: they answered that they would not, saying they were as good and faithful servants of the Emperor, as M. the Constable could be of the King his master. Thereupon our men by night hoisted up two great cannons, with the help of the Swiss soldiers and the lansquenets; but as ill luck would have it, when the cannons were in position, a gunner stupidly set fire to a bag full of gunpowder, whereby he was burned, with ten or twelve soldiers; and the flame of the powder discovered our artillery, so that all night long those within the castle fired their arquebuses at the place where they had caught sight of the cannons, and many of our men were killed and wounded. Next day, early in the morning, the attack was begun, and we soon made a breach in their wall. Then they demanded a parley; but it was too late, for meanwhile our French infantry, seeing them taken by surprise, mounted the breach, and cut them all in pieces, save one very fair young girl of Piedmont, whom a great seigneur would have. ... The captain and the ensign were taken alive, but soon afterward hanged and strangled on the battlements of the gate of the city, to give example and fear to the Emperor's soldiers, not to be so rash and mad as to wish to hold such places against so great an army. The soldiers within the castle, seeing our men come on them with great fury, did all they could to defend themselves, and killed and wounded many of our soldiers with pikes, arquebuses, and stones, whereby the surgeons had all their work cut out for them. Now I was at this time a fresh-water soldier; I had not yet seen wounds made by gunshot at the first dressing. It is true I had read in John de Vigo, first book, Of Wounds in General, eighth chapter, that wounds made by firearms partake of venenosity, by reason of the powder; and for their cure he bids you cauterise them with oil of elders scalding hot, mixed with a little treacle. And to make no mistake, before I would use the said oil, knowing this was to bring great pain to the patient, I asked first before I applied it, what the other surgeons did for the first dressing; which was to put the said oil, boiling well, into the wounds, with tents and setons; wherefore I took courage to do as they did. At last my oil ran short, and I was forced instead thereof to apply a digestive made of the yolks of eggs, oil of roses, and turpentine. In the night I could not sleep in quiet, fearing some default in not cauterising, that I should find the wounded to whom I had not used the said oil dead from the poison of their wounds; which made me rise very early to visit them, where beyond my expectation I found that those to whom I had applied my digestive medicament had but little pain, and their wounds without inflammation or swelling, having rested fairly well that night; the others, to whom the boiling oil was used, I found feverish, with great pain and swelling about the edges of their wounds. Then I resolved never more to burn thus cruelly poor men with gunshot wounds. While I was at Turin, I found a surgeon famed above all others for his treatment of gunshot wounds; into whose favour I found means to insinuate myself, to have the recipe of his balm, as he called it, wherewith he dressed gunshot wounds. And he made me pay my court to him for two years, before I could possibly draw the recipe from him. In the end, thanks to my gifts and presents, he gave it to me; which was to boil, in oil of lilies, young whelps just born, and earth-worms prepared with Venetian turpentine. Then I was joyful, and my heart made glad, that I had understood his remedy, which was like that which I had obtained by chance. See how I learned to treat gunshot wounds; not by books. My Lord Marshal Montejan remained Lieutenant-General for the King in Piedmont, having ten or twelve thousand men in garrison in the different cities and castles, who were often fighting among themselves with swords and other weapons, even with arquebuses. And if there were four wounded, I always had three of them; and if there were question of cutting off an arm or a leg, or of trepanning, or of reducing a fracture or a dislocation, I accomplished it all. The Lord Marshal sent me now hire now there to dress the soldiers committed to me who were wounded in other cities beside Turin, so that I was always in the country, one way or the other. M. the Marshal sent to Milan, to a physician of no less reputation than the late M. le Grand for his success in practice, to treat him for an hepatic flux, whereof in the end he died. This physician was some while at Turin to treat him, and was often called to visit the wounded, where always he found me; and I was used to consult with him, and with some other surgeons; and when we had resolved to do any serious work of surgery, it was Ambroise Pare that put his hand thereto, which I would do promptly and skilfully, and with great assurance, insomuch that the physician wondered at me, to be so ready in the operations of surgery, and I so young. One day, discoursing with the Lord Marshal, he said to him: "Signor, tu hai un Chirurgico giovane di anni, ma egli e vecchio di sapere e di esperientia: Guardato bene, perche egli ti fara servicio et honore." That is to say, "Thou hast a surgeon young in age, but he is old in knowledge and experience: take good care, of him, for he will do thee service and honour." But the good man did not know I had lived three years at the Hotel Dieu in Paris, with the patients there. In the end, M. the Marshal died of his hepatic flux. He being dead, the King sent M. the Marshal d'Annebaut to be in his place: who did me the honour to ask me to live with him, and he would treat me as well or better than M. the Marshal de Montejan. Which I would not do, for grief at the loss of my master, who loved me dearly; so I returned to Paris. THE JOURNEY TO MAROLLE AND LOW BRITTANY. 1543 I went to the Camp of Marolle, with the late M. de Rohan, as surgeon of his company; where was the King himself. M. d'Estampes, Governor of Brittany, had told the King how the English had hoist sail to land in Low Brittany; and had prayed him to send, to help him, MM. de Rohan and de Laval, because they were the seigneurs of that country, and by their help the country people would beat back the enemy, and keep them from landing. Having heard this, the King sent these seigneurs to go in haste to the help of their country; and to each was given as much power as to the Governor, so that they were all three the King's Lieutenants. They willingly took this charge upon them, and went off posting with good speed, and took me with them as far as Landreneau. There we found every one in arms, the tocsin sounding on every side, for a good five or six leagues round the harbours, Brent, Couquet, Crozon, le Fou, Doulac, Laudanec; each well furnished with artillery, as cannons, demi-cannons, culverins, muskets, falcons, arquebuses; in brief, all who came together were well equipped with all sorts and kinds of artillery, and with many soldiers, both Breton and French, to hinder the English from landing as they had resolved at their parting from England. The enemy's army came right under our cannons: and when we perceived them desiring to land, we saluted them with cannon- shot, and unmasked our forces and our artillery. They fled to sea again. I was right glad to see their ships set sail, which were in good number and good order, and seemed to be a forest moving upon the sea. I saw a thing also whereat I marvelled much, which was, that the balls of the great cannons made long rebounds, and grazed over the water as they do over the earth. Now to make the matter short, our English did us no harm, and returned safe and sound into England. And they leaving us in peace, we stayed in that country in garrison until we were assured that their army was dispersed. Now our soldiers used often to exercise themselves with running at the ring, or with fencing, so that there was always some one in trouble, and I had always something to employ me. M. d'Estampes, to make pastime and pleasure for the Seigneurs de Rohan and de Laval, and other gentlemen, got a number of village girls to come to the sports, to sing songs in the tongue of Low Brittany: wherein their harmony was like the croaking of frogs when they are in love. Moreover, he made them dance the Brittany triori, without moving feet or hips: he made the gentlemen see and hear many good things. At other tunes they made the wrestlers of the towns and Villages come, where there was a prize for the best: and the sport was not ended but that one or other had a leg or arm broken, or the shoulder or hip dislocated. There was a little man of Low Brittany, of a square body and well set, who long held the credit of the field, and by his skill and strength threw five or six to the ground. There came against him a big man, one Dativo, a pedagogue, who was said to be one of the best wrestlers in all Brittany: he entered into the lists, having thrown off his long jacket, in hose and doublet: when he was near the little man, it looked as though the little man had been tied to his girdle. Nevertheless, when they gripped each other round the neck, they were a long time without doing anything, and we thought they would remain equal in force and skill: but the little man suddenly leaped beneath this big Dativo, and took him on his shoulder, and threw him to earth on his back all spread out like a frog; and all the company laughed at the skill and strength of the little fellow. The great Dativo was furious to have been thus thrown to earth by so small a man: he rose again in a rage, and would have his revenge. They took hold again round the neck, and were again a good while at their hold without falling to the ground: but at last the big man let himself fall upon the little, and in falling put his elbow upon the pit of his stomach, and burst his heart, and killed him stark dead. And knowing he had given him his death's blow, took again his long cassock, and went away with his tail between his legs, and eclipsed himself. Seeing the little man came not again to himself, either for wine, vinegar, or any other thing presented to him, I drew near to him and felt his pulse, which did not beat at all: then I said he was dead. Then the Bretons, who were assisting at the wrestling, said aloud in their jargon, "Andraze meuraquet enes rac un bloa so abeuduex henelep e barz an gouremon enel ma hoa engoustun." That is to say, "That is not in the sport." And someone said that this great Dativo was accustomed to do so, and but a year past he had done the same at a wrestling. I must needs open the body to know the cause of this sudden death. I found much blood in the thorax. ... I tried to find some internal opening whence it might have come, which I could not, for all the diligence that I could use. ... The poor little wrestler was buried. I took leave of MM. de Rohan, de Laval, and d'Estampes. M. de Rohan made me a present of fifty double ducats and a horse, M. de Laval gave me a nag for my man, and M. d'Estampes gave me a diamond worth thirty crowns: and I returned to my house in Paris. THE JOURNEY TO PERPIGNAN. 1543 Some while after, M. de Rohan took me with him posting to the camp at Perpignan. While we were there, the enemy sallied out, and surrounded three pieces of our artillery before they were beaten back to the gates of the city. Which was not done without many killed and wounded, among the others M. de Brissac, who was then grand master of the artillery, with an arquebus-shot in the shoulder. When he retired to his tent, all the wounded followed him, hoping to be dressed by the surgeons who were to dress him. Being come to his tent and laid on his bed, the bullet was searched for by three or four of the best surgeons in the army, who could not find it, but said it had entered into his body. At last he called for me, to see if I could be more skilful than they, because he had known me in Piedmont. Then I made him rise from his bed, and told him to put himself in the same posture that he had when he was wounded, which he did, taking a javelin in his hand just as he had held his pike to fight. I put my hand around the wound, and found the bullet. ... Having found it, I showed them the place where it was, and it was taken out by M. Nicole Lavernot, surgeon of M. the Dauphin, who was the King's Lieutenant in that army; all the same, the honour of finding it belonged to me. I saw one very strange thing, which was this: a soldier in my presence gave one of his fellows a blow on the head with a halbard, penetrating to the left ventricle of the brain; yet the man did not fall to the ground. He that struck him said he heard that he had cheated at dice, and he had drawn a large sum of money from him, and was accustomed to cheat. They called me to dress him; which I did, as it were for the last time, knowing that he would die soon. When I had dressed him, he returned all alone to his quarters, which were at the least two hundred paces away. I bade one of his companions send for a priest to dispose the affairs of his soul; he got one for him, who stayed with him to his last breath. The next day, the patient sent for me by his girl, dressed in boy's apparel, to come and dress him; which I would not, fearing he would die under my hands; and to be rid of the matter I told her the dressing must not be removed before the third day. But in truth he was sure to die, though he were never touched again. The third day, he came staggering to find me in my tent, and the girl with him, and prayed me most affectionately to dress him, and showed me a purse wherein might be an hundred or sixscore pieces of gold, and said he would give me my heart's desire; nevertheless, for all that, I put off the removal of the dressing, fearing lest he should die then and there. Certain gentlemen desired me to go and dress him; which I did at their request; but in dressing him he died under my hands in a convulsion. The priest stayed with him till death, and seized his purse, for fear another man should take it, saying he would say masses for his poor soul. Also he took his clothes, and everything else. I have told this case for the wonder of it, that the soldier, having received this great blow, did not fall down, and kept his reason to the end. Not long afterward, the camp was broken up from diverse causes: one, because we were told that four companies of Spaniards were entered into Perpignan: the other, that the plague was spreading through the camp. Moreover, the country folk warned us there would soon be a great overflowing of the sea, which might drown us all. And the presage which they had, was a very great wind from sea, which rose so high that there remained not a single tent but was broken and thrown down, for all the care and diligence we could give; and the kitchens being all uncovered, the wind raised the dust and sand, which salted and powdered our meats in such fashion that we could not eat them; and we had to cook them in pots and other covered vessels. Nor was the camp so quickly moved but that many carts and carters, mules and mule drivers, were drowned in the sea, with great loss of baggage. When the camp was moved I returned to Paris. THE JOURNEY TO LANDRESY. 1544 The King raised a great army to victual Landresy. Against him the Emperor had no fewer men, but many more, to wit, eighteen thousand Germans, ten thousand Spaniards, six thousand Walloons, ten thousand English, and from thirteen to fourteen thousand horse. I saw the two armies near each other, within cannon-shot; and we thought they could not withdraw without giving battle. There were some foolish gentlemen who must needs approach the enemy's camp; the enemy fired on them with light field pieces; some died then and there, others had their arms or legs carried away. The King having done what he wished, which was to victual Landresy, withdrew his army to Guise, which was the day after All Saints, 1544; and from there I returned to Paris. A little while after, we went to Boulogne; where the English, seeing our army, left the forts which they were holding, Moulanabert, le petit Paradis, Monplaisir, the fort of Chastillon, le Portet, the fort of Dardelot. One day, as I was going through the camp to dress my wounded men, the enemy who were in the Tour d' Ordre fired a cannon against us, thinking to kill two men-at-arms who had stopped to talk together. It happened that the ball passed quite close to one of them, which threw him to the ground, and it was thought the ball had touched him, which it did not; but only the wind of the ball full against his corselet, with such force that all the outer part of his thigh became livid and black, and he could hardly stand. I dressed him, and made diverse scarifications to let out the bruised blood made by the wind of the ball; and by the rebounds that it made on the ground it killed four soldiers, who remained dead where they fell. I was not far from this shot, so that I could just feel the moved air, without its doing me any harm save a fright, which made me duck my head low enough; but the ball was already far away. The soldiers laughed at me, to be afraid of a ball which had already passed. Mon petit maistre, I think if you had been there, I should not have been afraid all alone, and you would have had your share of it. Monseigneur the Due de Guise, Francois de Lorraine, was wounded before Boulogne with a thrust of a lance, which entered above the right eye, toward the nose, and passed out on the other side between the ear and the back of the neck, with so great violence that the head of the lance, with a piece of the wood, was broken and remained fast; so that it could not be drawn but save with extreme force, with smith's pincers. Yet notwithstanding the great violence of the blow, which was not without fracture of bones, nerves, veins, and arteries, and other parts torn and broken, my lord, by the grace of God, was healed. He was used to go into battle always with his vizard raised: that is why the lance passed right out on the other side. THE JOURNEY TO GERMANY. 1552 I went to Germany, in the year 1552, with M. de Rohan, captain of fifty men-at-arms, where I was surgeon of his company, as I have said before. On this expedition, M. the Constable was general of the army; M. de Chastillon, afterward the Admiral, was chief colonel of the infantry, with four regiments of lansquenets under Captains Recrod and Ringrave, two under each; and every regiment was of ten ensigns, and every ensign of five hundred men. And beside these were Captain Chartel, who led the troops that the Protestant princes had sent to the King (this infantry was very fine, and was accompanied by fifteen hundred men-at-arms, with a following of two archers apiece, which would make four thousand five hundred horse); and two thousand light horse, and as many mounted arquebusiers, of whom M. d'Aumalle was general; and a great number of the nobility, who were come there for their pleasure. Moreover, the King was accompanied by two hundred gentlemen of his household, under the command of the Seigneurs de Boisy and de Canappe, and by many other princes. For his following, to escort him, there were the French and Scotch and Swiss guards, amounting to six hundred foot soldiers; and the companies of MM. the Dauphin, de 'Guise, d'Aumalle, and Marshal Saint Andre, amounting to four hundred lances; which was a marvellous thing, to see such a multitude; and with this equipage the King entered into Toul and Metz. I must not omit to say that the companies of MM. de Rohan, the Comte de Sancerre, and de Jarnac, which were each of them of fifty horse, went upon the wings of the camp. And God knows how scarce we were of victuals, and I protest before Him that at three diverse times I thought to die of hunger; and it was not for want of money, for I had enough of it; but we could not get victuals save by force, because the country people collected them all into the towns and castles. One of the servants of the captain-ensign of the company of M. de Rohan went with others to enter a church where the peasants were retreated, thinking to get victuals by love or by forces; but he got the worst of it, as they all did, and came back with seven sword wounds on the head, the least of which penetrated to the inner table of the skull; and he had four other wounds upon the arms, and one on the right shoulder, which cut more than half of the bladebone. He was brought back to his master's lodging, who seeing him so mutilated, and not hoping he could be cured, made him a grave, and would have cast him therein, saying that else the peasants would massacre and kill him: I in pity told him the man might still be cured if he were well dressed. Diverse gentlemen of the company prayed he would take him along with the baggage, since I was willing to dress him; to which he agreed, and after I had got the man ready, he was put in a cart, on a bed well covered and well arranged, drawn by a horse. I did him the office of physician, apothecary, surgeon, and cook. I dressed him to the end of his case, and God healed him; insomuch that all the three companies marvelled at this cure; The men-at-arms of the company of M. de Rohan, the first muster that was made, gave me each a crown, and the archers half a crown, THE JOURNEY TO DANVILLIERS. 1552 On his return from the expedition against the German camp, King Henry besieged Danvilliers, and those within would not surrender. They got the worst of it, but our powder failed us; so they had a good shot at our men. There was a culverin-shot passed through the tent of H. de Rohan, which hit a gentleman leg who was of his household. I had to finish the cutting off of it, which I did without applying the hot irons. The King sent for powder to Sedan, and when it came we began the attack mere vigorously than before, so that a breach was made. MM. de Guise and the Constable, being in the King's chamber, told him, and they agreed that next day they would assault the town, and were confident they would enter into it; and it must be kept secret, for fear the enemy should come to hear of it; and each promised not to speak of it to any man. Now there was a groom of the King's chamber, who being laid under the King's camp-bed to sleep, heard they were resolved to attack the town next day. So he told the secret to a certain captain, saying that they would make the attack next day for certain, and he had heard it from the King, and prayed the said captain to speak of it to no man, which he promised; but his promise did not hold, and forthwith he disclosed it to a captain, and this captain to a captain, and the captains to some of the soldiers, saying always, "Say nothing." And it was just so much hid, that next day early in the morning there was seen the greater part of the soldiers with their boots and breeches cut loose at the knee for the better mounting of the breach. The King was told of this rumour that ran through the camp, that the attack was to be made; whereat he was astonished, seeing there were but three in that advice, who had promised each other to tell it to no man. The King sent for M. de Guise, to know if he had spoken of this attack; he swore and affirmed to him he had not told it to anybody; and M. the Constable said the same, and told the King they must know for certain who had declared this secret counsel, seeing they were but three. Inquiry was made from captain to captain. In the end they found the truth; for one said, "It was such an one told me," and another said the same, till it came to the first of all, who declared he had heard it from the groom of the King's chamber, called Guyard, a native of Blois, son of a barber of the late King Francis. The King sent for him into his tent, in the presence of MM. de Guise and the Constable, to hear from him whence he had his knowledge, and who had told him the attack was to be made; and said if he did not speak the truth he would have him hanged. Then he declared he lay down under the King's bed thinking to sleep, and so having heard the plan he revealed it to a captain who was a friend of his, to the end he might prepare himself with his soldiers to be the first at the attack. Then the King knew the truth, and told him he should never serve him again, and that he deserved to be hanged, and forbade him ever to come again to the Court. The groom of the chamber went away with this to swallow, and slept that night with a surgeon-in-ordinary of the King, Master Louis of Saint Andre; and in the night he gave himself six stabs with a knife, and cut his throat Nor did the surgeon perceive it till the morning, when he found his bed all bloody, and the dead body by him. He marvelled at this sight on his awaking, and feared they would say he was the cause of the murder; but he was soon relieved, seeing the reason, which was despair at the loss of the good friendship of the King. So Guyard was buried. And those of Danvilliers, when they saw the breach large enough for us to enter, and our soldiers ready to assault them, surrendered themselves to the mercy of the King. Their leaders were taken prisoners, and their Soldiers were sent away without arms. The camp being dispersed, I returned to Paris with my gentleman whose leg I had cut off; I dressed him, and God healed him. I sent him to his house merry with a wooden leg; and he was content saying he had got off cheap, not to have been miserably burned to stop the blood, as you write in your book, won petit matetre, THE JOURNEY TO CHATEAU LE COMTE. 1552 Some time after. King Henry raised an army of thirty thousand men, to go and lay waste the country about Hesdin. The King of Navarre, who was then called M. de Vendosme, was chief of the army, and the King's Lieutenant. Being at St. Denis, in France, waiting while the companies passed by, he sent to Paris for me to speak with him. When I came he begged me (and his request was a command) to follow him on this journey; and I, wishing to make my excuses, saying my wife was sick in bed, he made answer there were physicians in Pairs to cure her, and he, too, had left his wife, who was of as good a house as mine, and he said he would use me well, and forthwith ordered I should be attached to his household. Seeing this great desire he had to take me with him, I dared not refuse him. I went after him to Chateau le Comte, within three or four leagues of Hesdin. The Emperor's soldiers were in garrison there, with a number of peasants from the country road. M. de Vendosme called on them to surrender; they made answer that he should never take them, unless it were piecemeal; let him do his worst, and they would do their best to defend themselves. They trusted in their moats, which were full of water; but in two hours, with plenty of faggots and casks, we made a way for our infantry to pass over, when they had to advance to the assault; and the place was attacked with five cannons, and a breach was made large enough for our men to enter; where those within received the attack very valiantly, and killed and wounded a great number of our men with arquebuses, pikes, and stones. In the end, when they saw themselves overpowered, they set fire to their powder and ammunition, whereby many of our men were burned, and some of their own. And they were almost all put to the sword; but some of our soldiers had taken twenty or thirty, hoping to have ransom for them: and so soon as this was known, orders were given to proclaim by trumpet through the camp, that all soldiers who had Spaniards for prisoners must kill them, on pain of being themselves hanged and strangled: which was done in cold blood. Thence we went and burned several villages; and the barns were all full of grain, to my very great regret. We came as far as Tournahan, where there was a large tower, whither the enemy withdrew, but we found the place empty: our men sacked it, and blew up the tower with a mine of gunpowder, which turned it upside down. After that, the camp was dispersed, and I returned to Paris. And the day after Chateau le Comte was taken, M. de Vendosme sent a gentleman under orders to the King, to report to him all that had happened, and among other things he told the King I had done very good work dressing the wounded, and had showed him eighteen bullets that I had taken out of their bodies, and there were many more that I had not been able to find or take out; and he spoke more good of me than there was by half. Then the King said he would take me into his service, and commanded M. de Goguier, his first physician, to write me down in the King's service as one of his surgeons-in-ordinary, and I was to meet him at Rheims within ten or twelve days: which I did. And the King did me the honour to command me to live near him, and he would be a good friend to me. Then I thanked him most humbly for the honour he was pleased to do me, in appointing me to serve him. THE JOURNEY TO METZ. 1552 The Emperor having besieged Metz with more than an hundred and twenty thousand men, and in the hardest time of winter,--it is still fresh in the minds of all--and there were five or six thousand men in the town, and among them seven princes; MM. le Duc de Guise, the King's Lieutenant, d'Enghien, de Conde, de la Montpensier, de la Roche-sur-Yon, de Nemours, and many other gentlemen, with a number of veteran captains and officers: who often sallied out against the enemy (as I shall tell hereafter), not without heavy loss on both sides. Our wounded died almost all, and it was thought the drugs wherewith they were dressed had been poisoned. Wherefore M. de Guise, and MM. the princes, went so far as to beg the King that if it were possible I should be sent to them with a supply of drugs, and they believed their drugs were poisoned, seeing that few of their wounded escaped. My belief is that there was no poison; but the severe cutlass and arquebus wounds, and the extreme cold, were the cause why so many died. The King wrote to M. the Marshal de Saint Andre, who was his Lieutenant at Verdun, to find means to get me into Metz, whatever way was possible. MM. the Marshal de Saint Andre, and the Marshal de Vielleville, won over an Italian captain, who promised to get me into the place, which he did (and for this he had fifteen hundred crowns). The King having heard the promise that the Italian captain had made, sent for me, and commanded me to take of his apothecary, named Daigne, so many and such drugs as I should think necessary for the wounded within the town; which I did, as much as a post-horse could carry. The King gave me messages to M. de Guise, and to the princes and the captains that were in Metz. When I came to Verdun, some days after, M. the Marshal de Saint Andre got horses for me and for my man, and for the Italian captain, who spoke excellent German, Spanish, and Walloon, beside his own mother-tongue. When we were within eight or ten leagues of Metz, we began to go by night only; and when we came near the enemy's camp I saw, more than a league and a half off, fires lighted all round the town, as if the whole earth were burning; and I believed we could never pass through these fires without being discovered, and therefore hanged and strangled, or cut in pieces, or made to pay a great ransom. To speak truth, I could well and gladly have wished myself back in Paris, for the great danger that I foresaw. God guided our business so well, that we entered into the town at midnight, thanks to a signal the captain had with another captain of the company of M. de Guise; to whom I went, and found him in bed, and he received me with high favour, being right glad at my coming. I gave him my message as the King had commanded me, and told him I had a little letter for him, and the next day I would not fail to deliver it. Then he ordered me a good lodging, and that I should be well treated, and said I must not fail next morning to be upon the breach, where I should find all the princes and seigneurs, and many captains. Which I did, and they received me with great joy, and did me the honour to embrace me, and tell me I was welcome; adding they would no more be afraid of dying, if they should happen to be wounded. M. le Prince de la Roche-sur-Yon was the first who entertained me, and inquired what they were saying at the Court concerning the town of Metz. I told him all that I chose to tell. Forthwith he begged me to go and see one of his gentlemen named M. de Magnane, now Chevalier of the Order of the King, and Lieutenant of His Majesty's Guards, who had his leg broken by a cannon-shot. I found him in bed, his leg bent and crooked, without any dressing on it, because a gentleman promised to cure him, having his name and his girdle, with certain words (and the poor patient was weeping and crying out with pain, not sleeping day or night for four days past). Then I laughed at such cheating and false promises; and I reduced and dressed his leg so skilfully that he was without pain, and slept all the night, and afterward, thanks be to God, he was healed, and is still living now, in the King's service. The Prince de la Roche-sur-Yon sent me a cask of wine, bigger than a pipe of Anjou, to my lodging, and told me when it was drunk, he would send me another; that was how he treated me, most generously. After this, M, de Guise gave me a list of certain captains and seigneurs, and bade me tell them what the King had charged me to say; which I did, and this was to commend him to them, and give them his thanks for the duty they had done and were doing in holding his town of Metz, and that he would remember it. I was more than eight days acquitting myself of this charge, because they were many. First, to all the princes; then to others, as the Duke Horace, the Count de Martigues, and his brother M. de Bauge, the Seigneurs de Montmorency and d'Anville, now Marshal of France, M. de la Chapelle aux Ursins, Bonnivet, Carouge, now Governor of Rouen, the Vidasme de Chartres, the Count de Lude, M. de Biron, now Marshal of France, M. de Randan, la Rochefoucaut, Bordaille, d' Estres the younger, M. de Saint Jehan en pauphine, and many others whom it would take too long to name; and also to many captains, who had all done their duty well for the defence of their lives and of the town. Afterward I asked M. de Guise what it pleased him I should do with the drugs I had brought with me; he bade me distribute them to the surgeons and apothecaries, and principally to the poor wounded soldiers, who were in great numbers in the Hospital. Which I did, and can truly say I could not so much as go and see all the wounded, who kept sending for me to visit and dress them. All the seigneurs within the town asked me to give special care, above all the rest; to M. de Pienne, who had been wounded, while on the breach, by a stone shot from a cannon, on the temple, with fracture and depression of the bone. They told me that so soon as he received the blow, he fell to the ground as dead, and cast forth blood by the mouth, nose, and ears, with great vomiting, and was fourteen days without being able to speak or reason; also he had tremors of a spasmodic nature, and all his face was swelled and livid, He was trepanned at the side of the temporal muscle, over the frontal bone. I dressed him, with other surgeons, and God healed him; and to-day he is still living, thank God. The Emperor attacked the town with forty double cannons, and the powder was not spared day or night. So soon as M. de Guise saw the artillery set and pointed to make a breach, he had the nearest houses pulled down and made into ramparts, and the beams and joists were put end to end, and between them faggots, earth, beds, and wool-packs; then they put above them other beams and joists as before. And there was plenty of wood from the houses in the suburbs; which had been razed to the ground, for fear the enemy should get under cover of them, and make use of the wood; it did very well for repairing the breach. Everybody was hard at work carrying earth to repair it, day and night; MM. the princes, the seigneurs, and captains, lieutenants, ensigns, were all carrying the basket, to set an example to the soldiers and citizens to do the like, which they did; even the ladies and girls, and those who had not baskets, made use of cauldrons, panniers, sacks, sheets, and all such things to carry the earth; so that the enemy had no sooner broken down the wall than they found behind it a yet stronger rampart. The wall having fallen, our men cried out at those outside, "Fox, fox, fox," and they vented a thousand insults against one another. M. de Guise forbade any man on pain of death to speak with those outside, for fear there should be some traitor who would betray what was being done within the town. After this order, our men tied live cats to the ends of their pikes, and put them over the wall and cried with the cats, "Miaut, Miaut." Truly the Imperials were much enraged, having been so long making a breach, at great loss, which was eighty paces wide, that fifty men of their front rank should enter in, only to find a rampart stronger than the wall. They threw themselves upon the poor cats, and shot them with arquebuses as men shoot at the popinjay. Our men often ran out upon them, by order of M. de Guise; a few days ago, our men had all made haste to enrol themselves in sallying-parties, chiefly the young nobility, led by experienced captains; and indeed it was doing them a great favour to let them issue from the town and run upon the enemy. They went forth always an hundred or six score men, well armed with cutlasses, arquebuses, pistols, pikes, partisans, and halbards; and advanced as far as the trenches, to take the enemy unawares. Then an alarum would be sounded all through the enemy's camp, and their drums would beat plan, plan, ta ti ta, ta ta ti ta, tou touf touf. Likewise their trumpets and clarions rang and sounded, To saddle, to saddle, to saddle, to horse, to horse, to horse, to saddle, to horse, to horse. And all their soldiers cried, "Arm, arm arm! to arms, to arms, to arms! arm, to arms, arm, to arms, arm":--like the hue-and-cry after wolves; and all diverse tongues, according to their nations; and you saw them come out of their tents and little lodgings, as thick as little ants when you uncover the ant-hills, to bring help to their comrades, who were having their throats cut like sheep. Their cavalry also came from all sides at full gallop, patati, patata, patati, patata, pa, ta, ta, patata pata, ta, eager to be in the thick of the fighting, to give and take their share of the blows. And when our men saw themselves hard pressed, they would turn back into the town, fighting all the way; and those pursuing them were driven back with cannon-shots, and the cannons were loaded with flint-stones and with big pieces of iron, square or three-sided. And our men on the wall fired a volley, and rained bullets on them as thick as hail, to send them back to their beds; whereas many remained dead on the field: and our men also did not all come back with whole skins, and there were always some left behind (as it were a tax levied on us) who were joyful to die on the bed of honour. And if there was a horse wounded, it was skinned and eaten by the soldiers, instead of beef and bacon; and if a man was wounded, I must run and dress him. Some days afterward there were other sallies, which infuriated the enemy, that we would not let him sleep a little in safety. M. de Guise played a trick upon them: he sent a peasant, who was none of the wisest, with two letters to the King, and gave him ten crowns, and promised the King would give him an hundred if he got the letters to him. In the one letter M. de Guise told the King that the enemy shewed no of retreating, and had put forth all their strength made a great breach, which he hoped to defend, even at the cost of his own life and of all who were in the town; and that the enemy had planted their artillery so well in a certain place (which he named) that it was with great difficulty he could keep them from entering the town, seeing it was the weakest place in the town; but soon he hoped to rebuild it well, so that they should not be able to enter. This letter was sewed in the lining of the man's doublet, and he was told to be very careful not to speak of it to any person. And the other letter was given to him, wherein M. de Guise told the King that he and all those besieged with him hoped to guard the town well; and other matters which I leave untold here. He sent out the man at night, and he was taken by the enemy's guard and brought to the Duke of Alva, that the Duke might hear what was doing in the town; and the peasant was asked if he had any letters. He said "Yes," and gave them the one; and they having seen it asked him if he had not another. He said "No." Then he was searched, and they found on him that which was sewed in his doubtlet; and the poor messenger was handed and strangled. The letters were taken to the Emperor, who called his council, where it was resolved, since they had been unable to do anything at the first breach, the artillery should forthwith be set against the place which they thought weakest, where they put forth all their strength to make a fresh breach; and they sapped and mined the wall, and tried hard to make a way into the Hell Tower, but dared not assault it openly. The Duke of Alva represented to the Emperor that every day their soldiers were dying, to the number of more than two hundred, and there was so little hope of entering the town, seeing the time of year and the great number of our soldiers who were in it. The Emperor asked what men they were who were dying, and whether they were gentlemen and men of mark; answer was made to him "They were all poor soldiers." Then said he, "It was no great loss if they died," comparing them to caterpillars, grasshoppers, and cockchafers, which eat up the buds and other good things of the earth; and if they were men of any worth they would not be in his camp at six livres the month, and therefore it was no great harm if they died. Moreover, he said he would never depart from the town till he had taken it by force or by famine, though he should lose all his army; because of the great number of princes who were shut up in it, with the greater part of the nobility of France, who he hoped would pay his expenses four times over; and he would go yet again to Paris, to see the Parisians, and to make himself King of all the kingdom of France. M. de Guise, with the princes, captains, and soldiers, and in general all the citizens of the town, having heard the Emperor's resolve to exterminate us all, forbade the soldiers and citizens, and even the princes and seigneurs, to eat fresh fish or venison, or partridges, woodcocks, larks, francolines, plovers, or other game, for fear these had acquired any pestilential air which could bring infection among us. So they had to content themselves with the fare of the army; biscuit, beef, salt cow-beef, bacon, cervelas, and Mayence hams; also fish, as haddock, salmon, shad, tunny, whale, anchovy, sardines, herrings; also peas, beans, rice, garlic, onions, prunes, cheeses, butter, oil, and salt; pepper, ginger, nutmegs and other spices to put in our pies, mostly of horses, which without the spice had a very bad taste. Many citizens, having gardens in the town, had planted them with fine radishes, turnips, carrots, and leeks, which they kept flourishing and very dear, for the extreme necessity of the famine. Now all these stores were distributed by weight, measure, and justice, according to the quality of the persons, because we knew not how long the siege would last. For after we heard the Emperors words, how he would not depart from before Metz, till he had taken it by force or by famine, the victuals were cut down; and what they used to distribute to three soldiers was given to four; and it was forbidden to them to sell the remains which might be left after their meals; but they might give them to the rabble. And they always rose from table with an appetite, for fear they should be subject to take physick. And before we surrendered to the mercy of the enemy, we had determined to eat the asses, mules, and horses, dogs, cats, and rats, even our boots and collars, and other skins that we could have softened and stewed. And, in a word, all the besieged were resolved to defend themselves valiantly with all instruments of war; to set the artillery at the entry of the breach, and load with balls, stones, cart-nails, bars and chains of iron; also all sorts and kinds of artificial fires, as barricadoes, grenades, stink-pots, torches, squibs, fire-traps, burning faggots; with boiling water, melted lead, and lime, to put out the enemy's eyes. Also, they were to make holes right through their houses, and put arquebusiers in them, to take the enemy in flank and hasten his going, or else give him stop then and there. Also they were to order the women to pull up the streets, and throw from their windows billets, tables, trestles, benches, and stools, to dash out the enemy's brains. Moreover, a little within the breach, there was a great stronghold full of carts and palisades, tuns and casks; and barricades of earth to serve as gabions, interlaid with falconets, falcons, field-pieces, crooked arquebuses, pistols, arquebuses, and wildfires, to break their legs and thighs, so that they would be taken from above and on the flank and from behind; and if they had carried this stronghold, there were others where the streets crossed, every hundred paces, which would have been as bad friends to them as the first, or worse, and would have made many widows and orphans. And if fortune had been so hard on us that they had stormed and broken up our strongholds, there would yet have been seven great companies, drawn up in square and in triangle, to fight them all at once, each led by one of the princes, for the better encouragement of our men to fight and die all together, even to the last breath of their souls. And all were resolved to bring their treasures, rings, and jewels, and their best and richest and most beautiful household stuffs, and burn them to ashes in the great square, lest the enemy should take them and make trophies of them. Also there were men charged to set fire to all the stores and burn them, and to stave in all the wine-casks; others to set fire to every single house, to burn the enemy and us together. The citizens thus were all of one mind, rather than see the bloody knife at their throats, and their wives and daughters ravished and taken by the cruel savage Spaniards. Now we had certain prisoners, who had been made secretly to understand our last determination and desperation; these prisoners M. de Guise sent away on parole, who being come to their camp, lost no time in saying what we had told them; which restrained the great and vehement desire of the enemy, so that they were no longer eager to enter the town to cut our throats and enrich themselves with the spoils. The Emperor, having heard the decision of this great warrior, M. de Guise, put water in his wine, and restrained his fury; saying that he could not enter the town save with vast butchery and carnage, and shedding of much blood, both of those defending and of those attacking, and they would be all dead together, and in the end he would get nothing but ashes; and afterward men might say it was a like destruction to that of the town of Jerusalem, made of old time by Titus and Vespasian. The Emperor thus having heard our last resolve, and seeing how little he had gained by his attack, sappings, and mines, and the great plague that was through all his camp, and the adverse time of the year, and the want of victuals and of money, and how his soldiers were disbanding themselves and going off in great companies, decided at last to raise the siege and go away, with the cavalry of his vanguard, and the greater part of the artillery and engines of war. The Marquis of Brandebourg was the last to budge from his place; he had with him some troops of Spaniards and Bohemians, and his German regiments, and there he stopped for a day and a half, to the great regret of M. de Guise, who brought four pieces of artillery out of the town, which he fired on him this side and that, to hurry him off: and off he went, sure enough, and all his men with him. When he was a quarter of a league from Metz, he was seized with a panic lest our cavalry should fall upon his tail; so he set fire to his store of powder, and left behind him some pieces of artillery, and a quantity of baggage, which he could not take along with him, because their vanguard and their great cannons had broken and torn tip the roads. Our cavalry were longing with all their hearts to issue from the town and attack him behind; but M. de Guise never let them, saying on the contrary we had better make their way smooth for them, and build them gold and silver bridges to let them go; like the good pastor and shepherd, who will not lose one of his sheep. That is how our dear and well-beloved Imperials went away from Metz, which was the day after Christmas Day, to the great content of those within the walls, and the praise of the princes, seigneurs, captains, and soldiers, who had endured the travail of this siege for more than two months. Nevertheless, they did not all go: there wanted more than twenty thousand of them, who were dead, from our artillery and the fighting, or from plague, cold, and starvation (and from spite and rage that they could not get into the town to cut our throats and plunder us): and many of their horses also died, the greater part whereof they had eaten instead of beef and bacon. We went where their camp had been, where we found many dead bodies not yet buried, and the earth all worked up, as one sees in the Cemetery of the Holy Innocents during some time of many deaths. In their tents, pavilions, and lodgings were many sick people. Also cannon-shot, weapons, carts, waggons, and other baggage, with a great quantity of soldier's bread, spoiled and rotted by the snows and rains (yet the soldiers had it but by weight and measure). Also they left a good store of wood, all that remained of the houses they had demolished and broken down in the villages for two or three leagues around; also many other pleasure-houses, that had belonged to our citizens, with gardens and fine orchards full of diverse fruit-trees. And without all this, they would have been benumbed and dead of the cold, and forced to raise the siege sooner than they did. M. de Guise had their dead buried, and their sick people treated. Also the enemy left behind them in the Abbey of Saint Arnoul many of their wounded soldiers, whom they could not possibly take with them. M. de Guise sent them all victuals enough, and ordered me and the other surgeons to go dress and physick them, which we did with good will; and I think they would not have done the like for our men. For the Spaniard is very cruel, treacherous, and inhuman, and so far enemy of all nations: which is proved by Lopez the Spaniard, and Benzo of Milan, and others who have written the history of America and the West Indies: who have had to confess that the cruelty, avarice, blasphemies, and wickedness of the Spaniards have utterly estranged the poor Indians from the religion that these Spaniards professed. And all write that they are of less worth than the idolatrous Indians, for their cruel treatment of these Indians. And some days later M. de Guise sent a trumpet to Thionville to the enemy, that they could send for their wounded in safety: which they did with carts and waggons, but not enough. M. de Guise gave them carts and carters, to help to take them to Thionville. Our carters, when they returned, told us the roads were all paved with dead bodies, and they never got half the men there, for they died in their carts: and the Spaniards seeing them at the point of death, before they had breathed their last, threw them out of the carts and buried them in the mud and mire, saying they had no orders to bring back dead men. Moreover, our carters said they had found on the roads many carts stuck in the mud, full of baggage, for which the enemy dared not send back, lest we who were within Metz should run out upon them. I would return to the reason why so many of them died; which was mostly starvation, the plague, and cold. For the snow was more than two feet deep upon the ground, and they were lodged in pits below the ground, covered only with a little thatch. Nevertheless, each soldier had his camp-bed, and a coverlet all strewed with stars, glittering and shining brighter than fine gold, and every day they had white sheets, and lodged at the sign of the Moon, and enjoyed themselves if only they had been able, and paid their host so well over night that in the morning they went off quits, shaking their ears; and they had no need of a comb to get the down and feathers out of their beards and hair, and they always found a white table-cloth, and would have enjoyed good meals but for want of food. Also the greater part of them had neither boots, half-boots, slippers, hose, nor shoes: and most of them would rather have none than any, because they were always in the mire up to mid-leg. And because they went bare- foot, we called them the Emperor's Apostles. After the camp was wholly dispersed, I distributed my patients into the hands of the surgeons of the town, to finish dressing them: then I took leave of M. de Guise, and returned to the King, who received me with great favour, and asked me how I had been able to make my way into Metz. I told him fully all that I had done. He gave me two hundred crowns, and an hundred which I had when I set out: and said he would never leave me poor. Then I thanked him very humbly for the good and the honour he was pleased to do me. THE JOURNEY TO HESDIN. 1553 The Emperor Charles laid siege to the town of Therouenne; and M. le Due de Savoie was General of his whole army. It was taken by assault: and there was a great number of our men killed and taken prisoners. The King, wishing to prevent the enemy from besieging the town and castle of Hesdin also, sent thither MM. le Duc de Bouillon, le Duc Horace, le Marquis de Villars, and a number of captains, and about eighteen hundred soldiers: and during the siege of Therouenne, these Seigneurs fortified the castle of Hesdin, so that it seemed to be impregnable. The King sent me to the Seigneurs, to help them with my art, if they should come to have need of it. Soon after the capture of Therouenne, we were besieged in Hesdin. There was a clear stream of running water within shot of our cannon, and about it were fourscore or an hundred of the enemy's rabble, drawing water. I was on a rampart watching the enemy pitch their camp; and, seeing the crowd of idlers round the stream, I asked M. du Pont, commissary of the artillery, to send one cannon-shot among this canaille: he gave me a flat refusal, saying that all this sort of people was not worth the powder would be wasted on them. Again I begged him to level the cannon, telling him, "The more dead, the fewer enemies;" which he did for my sake: and the shot killed fifteen or sixteen, and wounded many. Our men made sorties against the enemy, wherein many were killed and wounded on both sides, with gunshot or with fighting hand to hand; and our men often sallied out before their trenches were made; so that I had my work cut out for me, and had no rest either day or night for dressing the wounded. And here I would note that we had put many of them in a great tower, laying them on a little straw: and their pillows were stones, their coverlets were cloaks, those who had any. When the attack was made, so often as the enemy's cannons were fired, our wounded said they felt pain in their wounds, as if you had struck them with a stick: one was crying out on his head, the other on his arm, and so with the other parts of the body: and many had their wounds bleed again, even more profusely than at the time they were wounded, and then I had to run to staunch them. Mon petit maistre, if you had been there, you would have been much hindered with your hot irons; you would have wanted a lot of charcoal to heat them red, and sure you would have been killed like a calf for your cruelty. Many died of the diabolical storm of the echo of these engines of artillery, and the vehement agitation and severe shock of the air acting on their wounds; others because they got no rest for the shouting and crying that were made day and night, and for want of good food, and other things needful for their treatment. Mon petit maistre, if you had been there, no doubt you could have given them jelly, restoratives, gravies, pressed meats, broth, barley-water, almond-milk, blanc-mange, prunes, plums, and other food proper for the sick; but your diet would have been only on paper, and in fact they had nothing but beef of old shrunk cows, seized round Hesdin for our provision, salted and half-cooked, so that he who would eat it must drag at it with his teeth, as birds of prey tear their food. Nor must I forget the linen for dressing their wounds, which was only washed daily and dried at the fire, till it was as hard as parchment: I leave you to think how their wounds could do well. There were four big fat rascally women who had charge to whiten the linen, and were kept at it with the stick; and yet they had not water enough to do it, much less soap. That is how the poor patients died, for want of food and other necessary things. One day the enemy feigned a general attack, to draw our soldiers into the breach, that they might see what we were like: every man ran thither. We had made a great store of artificial fires to defend the breach; a priest of M. le Duc de Bouillon took a grenade, thinking to throw it at the enemy, and lighted it before he ought: it burst, and set fire to all our store, which was in a house near the breach. This was a terrible disaster for us, because it burned many poor soldiers; it even caught the house, and we had all been burned, but for help given to put it out; there was only one well in the castle with any water in it, and this was almost dry, and we took beer to put it out instead of water; afterward we were in great want of water, and to drink what was left we must strain it through napkins. The enemy, seeing the explosion and violence of the fires, which made a wonderful flame and thundering, thought we had lit them on purpose to defend the breach, and that we had many more of them. This made them change their minds, to have us some other way than by attack: they dug mines, and sapped the greater part of our walls, till they came near turning our castle altogether upside down; and when the sappers had finished their work, and their artillery was fired, all the castle shook under our feet like an earthquake, to our great astonishment. Moreover, they had levelled five pieces of artillery, which they had placed on a little hillock, so as to have us from behind when we were gone to defend the breach. M. le Duc Horace had a cannonshot on the elbow, which carried off his arm one way and his body the other, before he could say a single word; his death was a great disaster to us, for the high rank that he held in the town. Also M. de Martigues had a gunshot wound which pierced his lungs: I dressed him, as I shall tell hereafter. Then we asked leave to speak with the enemy; and a trumpet was sent to the Prince of Piedmont, to know what terms he would give us. He answered that all the leaders, such as gentlemen, captains, lieutenants, and ensigns, would be taken prisoners for ransom, and the soldiers would leave the town without their arms; and if we refused this fair and honest offer, we might rest assured they would take us next day, by attack or otherwise. A council was held, to which I was called, to know if I would sign the surrender of the town; with many captains, gentlemen, and others. I answered it was not possible to hold the town, and I would sign the surrender with my own blood, for the little hope I had we could resist the enemy's forces, and for the great longing I had to be out of this hell and utter torture; for I slept neither night nor day for the great number of the wounded, who were about two hundred. The dead were advanced in putrefaction, piled one upon the other like faggots, and not covered with earth, because we had none. And if I went into a soldier's lodging, there were soldiers waiting for me at the door when I came out, for me to dress others; it was who should have me, and they carried me like the body of a saint, with my feet off the ground, fighting for me. I could not satisfy this great number of wounded: nor had I got what I wanted for their treatment. For it is not enough that the surgeon do his duty toward his patients, but the patient also must do his; and the assistants, and external things, must work together for him: see Hippocrates, Aphorism the First. Having heard that we were to surrender the place, I knew our business was not prospering; and for fear of being known, I gave a velvet coat, a satin doublet, and a cloak of fine cloth trimmed with velvet, to a soldier; who gave me a bad doublet all torn and ragged with wear, and a frayed leather collar, and a bad hat, and a short cloak; I dirtied the neck of my shirt with water mixed with a little soot, I rubbed my hose with a stone at the knees and over the heels, as though they had been long worn, I did the same to my shoes, till one would have taken me for a chimney- sweep rather than a King's surgeon. I went in this gear to M. de Martigues, and prayed him to arrange I should stop with him to dress him; which he granted very willingly, and was as glad I should be near him as I was myself. Soon afterward, the commissioners who were to select the prisoners entered the castle, the seventeenth day of July, 1553. They took prisoners MM. le Due de Bouillon, le Marquis de Villars, de Roze, le Baron de Culan, M. du Pont, commissary of the artillery, and M. de Martigues; and me with him, because he asked them; and all the gentlemen who they knew could pay ransom, and most of the soldiers and the leaders of companies; so many and such prisoners as they wished. And then the Spanish soldiers entered by the breach, unresisted; our men thought they would keep their faith and agreement that all lives should be spared. They entered the town in a fury to kill, plunder, and ravage everything: they took a few men, hoping to have ransom for them. ... If they saw they could not get it, they cruelly put them to death in cold blood. ... And they killed them all with daggers, and cut their throats. Such was their great cruelty and treachery; let him trust them who will. To return to my story: when I was taken from the castle into the town, with M. de Martigues, there was one of M. de Savoie's gentlemen, who asked me if M. de Martigues's wound could be cured. I told him no, that it was incurable: and off he went to tell M. le Due de Savoie. I bethought myself they would send physicians and surgeons to dress M. de Martigues; and I argued within myself if I ought to play the simpleton, and not let myself be known for a surgeon, lest they should keep me to dress their wounded, and in the end I should be found to be the King's surgeon, and they would make me pay a big ransom. On the other hand, I feared, if I did not show I was a surgeon and had dressed M. de Martigues skilfully, they would cut my throat. Forthwith I made up my mind to show them he would not die for want of having been well dressed and nursed. Soon after, sure enough, there came many gentlemen, with the Emperor's physician, and his surgeon, and those belonging to M. de Savoie, and six other surgeons of his army, to see M. de Martigues's wound, and to know of me how I had dressed and treated it. The Emperor's physician bade me declare the essential nature of the wound, and what I had done for it. And all his assistants kept their ears wide open, to know if the wound were or were not mortal. I commenced my discourse to them, how M. Martigues, looking over the wall to mark those who were sapping it, was shot with an arquebus through the body, and I was called of a sudden to dress him. I found blood coming from his mouth and from his wounds. Moreover, he bad a great difficulty of breathing in and out, and air came whistling from the wounds, so that it would have put out a candle; and he said he had a very great stabbing pain where the bullet had entered. ... I withdrew some scales of bone, and put in each wound a tent with a large head, fastened with a thread, lest on inspiration it should be drawn into the cavity of the chest; which has happened with surgeons, to the detriment of the poor wounded; for being fallen in, you cannot get them out; and then they beget corruption, being foreign bodies. The tents were anointed with a preparation of yolk of egg, Venice turpentine, and a little oil of roses. ... I put over the wounds a great plaster of diachylum, wherewith I had mixed oil of roses, and vinegar, to avoid inflammation. Then I applied great compresses steeped in oxycrate, and bandaged him, not too tight, that he might breathe easily. Next, I drew five basons of blood from his right arm, considering his youth and his sanguine temperament. ... Fever took him, soon after he was wounded, with feebleness of the heart. ... His diet was barley- water, prunes with sugar, at other times broth: his drink was a ptisane. He could lie only on his back. ... What more shall I say? but that my Lord de Martigues never had an hour's rest after he was wounded. ... These things considered, Gentlemen, no other prognosis is possible, save that he will die in a few days, to my great grief. Having finished my discourse, I dressed him as I was accustomed. When I displayed his wounds, the physicians and surgeons, and other assistants present, knew the truth of what I had said. The physicians, having felt his pulse and seen that the vital forces were depressed and spent, agreed with me that in a few days he would die. Then they all went to the Duc de Savoie, and told him M. de Martigues would die in a short time. He answered them, "Possibly, if he had been well dressed, he might have escaped death." Then they all with one voice said he had been very well dressed and cared for altogether, and it could not be better, and it was impossible to cure him, and his wound was of necessity mortal. Then M. de Savoie was very angry with them, and cried, and asked them again if for certain they all held his case hopeless: they answered, yes. Then a Spanish impostor came forward, who promised on his life to cure him; and if he did not, they should cut him in an hundred pieces; but he would have no physicians, nor surgeons nor apothecaries with him: and M. le Duc de Savoie forthwith bade the physicians and surgeons not go near M. de Martigues; and sent a gentleman to bid me, under pain of death, not so much as to touch him. Which I promised, and was very glad, for now he would not die under my hands; and the impostor was told to dress him, and to have with him no other physicians or surgeons, but only himself. By and bye he came, and said to M. de Martigues, "Senor Cavallero, M. de Savoie has bid me come and dress your wound. I swear to God, before eight days I will set you on horseback, lance in hand, provided none touch you but I alone. You shall eat and drink whatever you like. I will be dieted instead of you; and you may trust me to perform what I promise. I have cured many who had worse wounds than yours." And the Seigneurs answered him, "God give you His grace for it." He asked for a shirt of M. de Martigues, and tore it in little strips, which he laid cross-wise, muttering and murmuring certain words over the wounds: having done this much for him, he let him eat and drink all he would, saying he himself would be dieted in his stead; which he did, eating but six prunes and six morsels of bread for dinner, and drinking only beer. Nevertheless, two days later, M. de Martigues died: and my friend the Spaniard, seeing him at the point of death, eclipsed himself, and got away without good-bye to any man. And I believe if he had been caught he would have been hanged and strangled, for the false promise he made to M. le Due de Savoie and many other gentlemen. M. de Martigues died about ten o'clock in the morning; and after dinner M. de Savoie sent the physicians and surgeons, and his apothecary, with a store of drugs to embalm him. They came with many gentlemen and captains of his army. The Emperor's surgeon came to me, and asked me in a very friendly way to make, the embalmment; which I refused, saying that I was not worthy to carry his instrument-box after him. He begged me again to do it to please him, and that he would be very glad of it...Seeing his kindness, and fearing to displease him, I then decided to show them the anatomist that I was, expounding to them many things, which would here be too long to recite... Our discourse finished, I embalmed the body; and it was placed in a coffin. Then the Emperor's surgeon drew me aside, and told me, if I would stop with him, he would treat me well, and give me a new suit of clothes, and set me on horseback. I gave him many thanks, and said I had no wish to serve any country but my own. Then he told me I was a fool, and if he were a prisoner as I was, he would serve a devil to get his freedom. In the end I told him flat I would not stop with him. The Emperor's physician then went back to M. de Savoie, and explained to him the causes of M. de Martigues' death, and that it was impossible for all the men in the world to have cured him; and assured him again I had done all that was to be done, and besought him to take me into his service; saying much more good of me than there was. He having been persuaded to do this, sent to me one of his stewards, M. du Bouchet, to tell me, if I would serve him, he would use me well; I sent back my very humble thanks, and that I had decided not to take service under any foreigner. When he heard my answer he was very angry, and said I ought to be sent to the galleys. M. de Vaudeville, Governor of Graveline, and colonel of seventeen ensigns of infantry, asked him to send me to him, to dress an old ulcer on his leg, that he had had for six or seven years. M. de Savoie said he was willing, so far as I was concerned; and if I used the cautery to his leg, it would serve him right. M. de Vaudeville answered, if he saw me trying it, he would have my throat cut. Soon after, he sent for me four German halberdiers of his guard; and I was terrified, for I did not know where they were taking me: they spoke no more French than I German. When I was come to his lodging, he bade me welcome, and said, now I belonged to him; and so soon as I had healed him, he would let me go without ransom. I told him I had no means to pay any ransom. He called his physician and his surgeon-in-ordinary, to show me his leg; and when we had examined it, we withdrew into a room, where I began my discourse to them. ... Then the physician left me with the surgeon, and went back to M. de Vaudeville, and said he was sure I could cure him, and told him all I had decided to do; which pleased him vastly. He sent for me, and asked if I thought I could cure him; I said yes, if he were obedient to what was necessary. He promised to do only what I wished and ordered; and so soon as he was healed, he would let me go home without ransom. Then I asked him to make better terms with me, saying it was too long to wait for my liberty: in fifteen days I hoped his ulcer would be less than half its present size, and give no pain; then his own surgeon and physician could finish the cure. He granted this to me. Then I took a piece of paper to measure the size of the ulcer, and gave it to him, and kept another by me; I asked him to keep his promise, when I had done my work; he swore by the faith of a gentleman he would. Then I set myself to dress him properly, after the manner of Galen. ... He wished to know if it were true, what I said of Galen, and bade his physician look to it, for he would know it for himself; he had the book put on the table, and found that what I said was true; so the physician was ashamed, and I was glad. Within the fifteen days, it was almost all healed; and I began to feel happy about the compact made between us. He had me to eat and drink at his table, when there were no more great persons than he and I only. He gave me a big red scarf which I must wear; which made me feel something like a dog when they give him a clog, to stop him eating the grapes in the vineyards. His physician and surgeon took me through the camp to visit their wounded; and I took care to observe what our enemy was doing. I found they had no more great cannons, but only twenty-five or thirty field-pieces. M. de Vaudeville held prisoner M. de Bauge, brother of M. de Martigues who died at Hesdin. M. de Bauge was prisoner at Chateau de La Motte au Bois, belonging to the Emperor; he had been captured at Therouenne by two Spanish soldiers; and M. de Vaudeville, when he saw him there, concluded he must be some gentleman of good family: he made him pull off his stockings, and seeing his clean legs and feet, and his fine white stockings, knew he was one to pay a good ransom. He told the soldiers he would give them thirty crowns down for their prisoner: they agreed gladly, for they had no place to keep him, nor food for him, nor did they know his value: so they gave their man into his hands, and he sent him off at once, guarded by four of his own soldiers, to Chateau de La Motte au Bois, with others of our gentlemen who were prisoners. M. de Bauge would not tell who he was; and endured much hardship, living on bread and water, with a little straw for his bed. When Hesdin was taken, M. de Vaudeville sent the news of it to him and to the other prisoners, and the list of the killed, and among them M. de Martigues: and when M. de Bauge heard with his own ears his brother was dead, he fell to crying, weeping, and lamentation. His guards asked him why he was so miserable: he told them, for love of M. de Martigues, his brother. When he heard this, the captain of the castle sent straight to tell M. de Vaudeville he had a good prisoner: who was delighted at this, and sent me next day with four soldiers, and his own physician, to the castle, to say that if M. de Bauge would pay him fifteen thousand crowns ransom, he would send him home free: and he asked only the security of two Antwerp merchants that he should name. M. de Vaudeville persuaded me I should commend this offer to his prisoner: that is why he sent me to the castle. He told the captain to treat him well and put him in a room with hangings, and strengthen his guard: and from that time onward they made a great deal of him, at the expense of M. de Vaudeville. M. de Bauge answered that he could not pay his ransom himself: it depended on M. d' Estampes his uncle, and Mlle. de Bressure his aunt: he had no means to pay such a ransom. I went back with my guards, and gave this answer to M. de Vaudeville; who said, "Possibly he will not get away so cheap": which was true, for they knew who he was. Then the Queen of Hungary and M. le Duc de Savoie sent word to M. de Vaudeville that this mouthful was too big for him, and he must send his prisoner to them (which he did), and he had other prisoners enough without him. The ransom paid was forty thousand crowns, without other expenses. On my way back to M. de Vaudeville, I passed by Saint Omer, where I saw their great cannons, most of which were fouled and broken. Also I passed by Therouenne, where I saw not one stone left on another, save a vestige of the great church: for the Emperor ordered the country people for five or six leagues round to clear and take away the stones; so that now you may drive a cart over the town: and the same at Hesdin, and no trace of castle and fortress. Such is the evil that wars bring with them. To return to my story; M. de Vaudeville soon got the better of his ulcer, and was nearly healed: so he let me go, and sent me by a trumpet, with passport, as far as Abbeville. I posted from here, and went to find my master, King Henry, at Aufimon, who received me gladly and with good favour. He sent MM. de Guise, the Constable, and d' Estres, to hear from me the capture of Hesdin; and I made them a true report, and assured them I had seen the great cannons they had taken to Saint Omer: and the King was glad, for he had feared the enemy would come further into France. He gave me two hundred crowns to take me home: and I was thankful to be free, out of this great torment and thunder of the diabolical artillery, and away from the soldiers, blasphemers and deniers of God. I must add that after Hesdin was taken, the King was told I was not killed but taken prisoner. He made M. Goguier, his chief physician, write to my wife that I was living, and she was not to be unhappy, and he would pay my ransom. BATTLE OF SAINT QUENTIN. 1557 After the battle of Saint Quentin, the King sent me to La Fere en Tartenois, to M. le Marechal de Bourdillon, for a passport to M. le Duc de Savoie, that I might go and dress the Constable, who had been badly wounded in the back with a pistol-shot, whereof he was like to die, and remained prisoner in the enemy's hands. But never would M. le Duc de Savoie let me go to him, saying he would not die for want of a surgeon; that he much doubted I would go there only to dress him, and not rather to take some secret information to him; and that he knew I was privy to other things besides surgery, and remembered I had been his prisoner at Hesdin. M. le Marechal told the King of this refusal: who wrote to M. le Marechal, that if Mme. the Constable's Lady would send some quick-witted man of her household I would give him a letter, and had also something to say to him by word of mouth, entrusted to me by the King and by M. le Cardinal de Lorraine. Two days later there came one of the Constable's gentlemen of the bedchamber, with his shirts and other linen, to whom M. le Marechal gave a passport to go to the Constable. I was very glad, and gave him my letter, and instructed him what his master must do now he was prisoner. I thought, having finished my mission, to return to the King; but M. le Marechal begged me to stop at La Fere with him, to dress a very great number of wounded who had retreated there after the battle, and he would write to the King to explain why I stopped; which I did. Their wounds were very putrid, and full of worms, with gangrene, and corruption; and I had to make free play with the knife to cut off what was corrupt, which was not done without amputation of arms and legs, and also sundry trepannings. They found no store of drugs at La Fere, because the surgeons of the camp had taken them all away; but I found the waggons of the artillery there, and these had not been touched. I asked M. le Marechal to let me have some of the drugs which were in them, which he did; and I was given the half only at one time, and five or six days later I had to take the rest; and yet it was not half enough to dress the great number of wounded. And to correct and stop the corruption, and kill the worms in their wounds, I washed them with Aegyptiacum dissolved in wine and eau-de-vie, and did all I could for them; but in spite of all my care many of them died. There were at La Fere some gentlemen charged to find the dead body of M. de Bois-Dauphin the elder, who had been killed in the battle; they asked me to go with them to the camp, to pick him out, if we could, among the dead; but it was not possible to recognize him, the bodies being all far gone in corruption, and their faces changed. We saw more than half a league round us the earth all covered with the dead; and hardly stopped there, because of the stench of the dead men and their horses; and so many blue and green flies rose from them, bred of the moisture of the bodies and the heat of the sun, that when they were up in the air they hid the sun. It was wonderful to hear them buzzing; and where they settled, there they infected the air, and brought the plague with them. Mon petit maistre, I wish you had been there with me, to experience the smells, and make report thereof to them that were not there. I was very weary of the place; I prayed M. le Marechal to let me leave it, and feared I should be ill there; for the wounded men stank past all bearing, and they died nearly all, in spite of everything we did. He got surgeons to finish the treatment of them, and sent me away with his good favour. He wrote to the King of the diligence I had shown toward the poor wounded. Then I returned to Paris, where I found many more gentlemen, who had been wounded and gone thither after the battle. THE JOURNEY TO THE CAMP AT AMIENS. 1558 The King sent me to Dourlan, under conduct of Captain Gouast; with fifty men-at-arms, for fear I should be taken by the enemy; and seeing we were always in alarms on the way, I made my man let down, and made him the master; for I got on his horse, which carried my valise, and could go well if we had to make our escape, and I took his cloak and hat and gave him my mount, which was a good little mare; he being in front, you would have taken him for the master and me for the servant The garrison inside Dourlan, when they saw us, thought we were the enemy, and fired their cannon at us. Captain Gouast, my conductor, made signs to them with his hat that we were not the enemy; at last they ceased firing, and we entered Dourlan, to our great relief. Five or six days before this, a sortie had been made from Dourlan; wherein many captains and brave soldiers had been killed or wounded: and among the wounded was Captain Saint Aubin, vaillant comme l' espce, a great friend of M. de Guise: for whose sake chiefly the King had sent me there. Who, being attacked with a quartan fever, yet left his bed to command the greater part of his company. A Spaniard, seeing him in command, perceived he was a captain, and shot him through the neck with an arquebus. Captain Saint Aubin thought himself killed; and by this fright I protest to God he lost his quartan fever, and was forever free of it. I dressed him, with Antoine Portail, surgeon-in-ordinary of the King; and many other soldiers. Some died, others got off with the loss of an arm or a leg or an eye, and said they had got off cheap, to be alive at all. Then, the enemy having broken up their camp, I returned to Paris. I say nothing here of mon petit maistre, who was more comfortable in his house than I at the wars. THE JOURNEY TO BOURGES. 1562 The King with his camp was but a short time at Bourges, till those within the walls should surrender; and they came out with their goods saved. I know nothing worth remembering, but that a boy of the King's kitchen, having come near the walls of the town before the agreement had been signed, cried with a loud voice, "Huguenot, Huguenot, shoot here, shoot here," having his arm thrown up and his hand spread out; a soldier shot his hand right through with a bullet. When he was thus shot, he came to find me to dress him. And the Constable seeing the boy in tears, with his hand all bloody, asked who had wounded him: then a gentleman who had seen him shot said it served him right, because he kept calling "Huguenot, hit here, aim here." And then the Constable said, this Huguenot was a good shot and a good fellow, for most likely if he had chosen to fire at the boy's head, he would have hit it even more easily than his hand. I dressed the kitchen boy, who was very ill. He recovered, but with no power in his hand: and from that time his comrades called him "Huguenot": he is still living now. THE JOURNEY TO ROUEN. 1562 Now, as for the capture of Rouen, they killed many of our men both before and at the attack: and the very next day after we had entered the town, I trepanned eight or nine of our men, who had been wounded with stones as they were on the breach. The air was so malignant, that many died, even of quite small wounds, so that some thought the bullets had been poisoned; and those within the town said the like of us; for though they had within the town all that was needful, yet all the same they died like those outside. The King of Navarre was wounded, some days before the attack, with a bullet in the shoulder. I visited him, and helped to dress him, with one of his own surgeons, Master Gilbert, one of the chief men of Montpellier, and others. They could not find the bullet. I searched for it very accurately, and found reason to believe it had entered at the top of the arm, by the head of the bone, and had passed into the hollow part of the bone, which was why they could not find it; and most of them said it had entered his body and was lost in it. M. le Prince de La Roche-sur-Yon, who dearly loved the King of Navarre, drew me aside and asked if the wound were mortal. I told him yes, because all wounds of great joints, and especially contused wounds, were mortal, according to all those who have written about them. He asked the others what they thought of it, and chiefly Master Gilbert, who told him he had great hope his Lord the King would recover; which made the Prince very glad. Four days later, the King, and the Queen-mother, and M. le Cardinal de Bourbon, his brother, and M. le Prince de la Roche- sur-Yon, and M. de Guise, and other great persons, after we had dressed the King of Navarre, wished us to hold a consultation in their presence, all the physicians and surgeons together. Each of them said what he thought, and there was not one but had good hope, they said, that he would recover. I persisted always in the contrary. M. le Prince, who loved me, drew me aside, and said I was alone against the opinion of all the others, and prayed me not to be obstinate against so many good men. I answered, When I shall see good signs of recovery, I will change my mind. Many consultations were held, and I never changed what I said, and the prognosis I had made at the first dressing, and said always the arm would fall into a gangrene: which it did, for all the care they could give to it; and he rendered his spirit to God the eighteenth day after his wound. M. le Prince, having heard of it, sent to me his surgeon, and his physician, one Lefevre, now physician-in-ordinary to the King and Queen-mother, to say he wished to have the bullet, and we were to look for it, to see where it was. Then I was very glad, and assured them I should quickly find it; which I did in their presence, with many other gentlemen: it was just in the very middle of the bone. M. le Prince took and showed it to the King and to the Queen, who all said that my prognosis had come true. The body was laid to rest at Chateau Gaillard: and I returned to Paris, where I found many patients, who had been wounded on the breach at Rouen, and chiefly Italians, who were very eager I should dress them: which I did willingly. Many of them recovered: the rest died. Mon petit maistre, I think you were called to dress some, for the great number there was of them. THE BATTLE OF DREUX. 1562 The day after the battle of Dreux, the King bade me go and dress M. le Comte d'Eu, who had been wounded in the right thigh, near the hip-joint, with a pistol-shot: which had smashed and broken the thigh-bone into many pieces: whereon many accidents supervened, and at last death, to my great grief. The day after I came, I would go to the camp where the battle had been, to see the dead bodies. I saw, for a long league round, the earth all covered: they estimated it at twenty-five thousand men or more; and it was all done in less than two hours. I wish, mon petit maistre, for the love I bear you, you had been there, to tell it to your scholars and your children. Now while I was at Dreux, I visited and dressed a great number of gentlemen, and poor soldiers, and among the rest many of the Swiss captains. I dressed fourteen all in one room, all wounded with pistol-shots and other diabolical firearms, and not one of the fourteen died. M. le Comte d'Eu being dead, I made no long stay at Dreux. Surgeons came from Paris, who fulfilled their duty to the wounded, as Pigray, Cointeret, Hubert, and others; and I returned to Paris, where I found many wounded gentlemen who had retreated thither after the battle, to have their wounds dressed; and I was not there without seeing many of them. THE JOURNEY TO HAVRE DE GRACE. 1563 And I will not omit to tell of the camp at Havre de Grace. When our artillery came before the walls of the town, the English within the walls killed some of our men, and several pioneers who were making gabions. And seeing they were so wounded that there was no hope of curing them, their comrades stripped them, and put them still living inside the gabions, which served to fill them up. When the English saw that they could not withstand our attack, because they were hard hit by sickness, and especially by the plague, they surrendered. The King gave them ships to return to England, very glad to be out of this plague-stricken place. The greater part of them died, and they took the plague to England, and they have not got rid of it since. Captain Sarlabous, master of the camp, was left in garrison, with six ensigns of infantry, who had no fear of the plague; and they were very glad to get into the town, hoping to enjoy themselves there, Mon petit maistre, if you had been there, you would have done as they did. THE JOURNEY TO BAYONNE. 1564 I went with the King on that journey to Bayonne, when we were two years and more making the tour of well-nigh all this kingdom. And in many towns and villages I was called in consultation over sundry diseases, with the late M. Chapelain, chief physician to the King, and M. Castellan, chief physician to the Queen-mother; honorable men and very learned in medicine and surgery. During this journey, I always inquired of the surgeons if they had noted anything rare in their practices, so that I might learn something new. While I was at Bayonne, two things happened worthy of remark by young surgeons. The first is, I dressed a Spanish gentleman, who had a great and enormous swelling of the throat. He had lately been touched by the deceased King Charles for the king's evil. I opened his swelling. ... I left him in the hands of a surgeon of the town, to finish his cure. M. de Fontaine, Knight of the Order of the King, had a severe continued pestilent fever, accompanied with many inflammatory swellings in sundry parts of the body. He had bleeding at the nose for two days, without ceasing, nor could we staunch it: and after this haemorrhage the fever ceased, with much sweating, and by and bye the swellings suppurated, and he was dressed by me, and healed by the grace of God. BATTLE OF SAINT DENIS, 1567 As for the battle of Saint Denis, there were many killed on both sides. Our wounded withdrew to Paris to be dressed, with the prisoners they had taken, and I dressed many of them. The King ordered me, at the request of Mme. the Constable's Lady, to go to her house to dress the Constable; who had a pistol-shot in the middle of the spine of his back, whereby at once he lost all feeling and movement in his thighs and legs ... because the spinal cord, whence arise the nerves to give feeling and movement to the parts below, was crushed, broken, and torn by the force of the bullet. Also he lost understanding and reason, and in a few days he died. The surgeons of Paris were hard put to it for many days to treat all the wounded. I think, mon petit maistre, you saw some of them. I beseech the great God of victories, that we be never more employed in such misfortune and disaster. VOYAGE OF THE BATTLE OF MONCONTOUR. 1569 During the battle of Moncontour, King Charles was at Plessis-les- Tours, where he heard the news of the victory. A great number of gentlemen and soldiers retreated into the town and suburbs of Tours, wounded, to be dressed and treated; and the King and the Queen-mother bade me do my duty by them, with other surgeons who were then on duty, as Pigray, du Bois, Portail, and one Siret, a surgeon of Tours, a man well versed in surgery, who was at this time surgeon to the King's brother. And for the multitude of bad cases we had scarce any rest, nor the physicians either. M. le Comte de Mansfeld, Governor of the Duchy of Luxembourg, Knight of the Order of the King, was severely wounded in the battle, in the left arm, with a pistol-shot which broke a great part of his elbow; and he withdrew to Borgueil near Tours. Then he sent a gentleman to the King, to beg him to send one of his surgeons, to help him of his wound. So they debated which surgeon they should send. M. le Marechal de Montmorency told the King and the Queen that they ought to send him their chief surgeon; and urged that M. de Mansfeld had done much toward the victory. The King said flat, he would not have me go, and wished me to stop with himself. Then the Queen-mother told him I would but go and come back, and he must remember it was a foreign lord, who had come, at the command of the King of Spain, to help him. then he let me go, provided I came back very soon. So he sent for me, and the Queen-mother with him, and bade me go and find the Lord de Mansfeld, wherever he should be, to do all I could for him to heal his wound. I went to him, with a letter from Their Majesties. When he saw it, he received me with good-will, and forthwith dismissed three or four surgeons who were dressing him; which was to my very great regret, because his wound seemed to me incurable. Now many gentlemen had retreated to Borgueil, having been wounded: for they knew that M. de Guise was there, who also had been badly wounded with a pistol-shot through the leg, and they were sure that he would have good surgeons to dress him, and would help them, as he is kindly and very generous, and would relieve their wants. This he did with a will, both for their eating and drinking, and for what else they needed: and for my part, they had the comfort and help of my art: some died, others recovered, according to their wounds. M. le Comte Ringrave died, who was shot in the shoulder, like the King of Navarre before Rouen. M. de Bassompierre, colonel of twelve hundred horse, was wounded by a similar shot, in the same place, as M. de Mansfeld: whom I dressed, and God healed. God blessed my work so well, that in three weeks I sent them back to Paris: where I had still to make incisions in M. de Mansfeld's arm, to remove some pieces of the bones, which were badly splintered, broken, and carious. He was healed by the grace of God, and made me a handsome present, so I was well content with him, and he with me; as he has shown me since. He wrote a letter to M. le Duc d' Ascot, how he was healed of his wound, and also M. de Bassompierre of his, and many others whom I had dressed after the battle of Moncontour; and advised him to ask the King of France to let me visit M. le Marquis d' Auret, his brother: which he did. THE JOURNEY TO FLANDERS. 1569 M. le Duc d' Ascot did not fail to send a gentleman to the King, with a letter humbly asking he would do him so much kindness and honour as to permit and command his chief surgeon to visit M. le Marquis d' Auret, his brother, who had received a gunshot wound near the knee, with fracture of the bone, about seven months ago, and the physicians and surgeons all this time had not been able to heal him. The King sent for me and bade me go and see M. d' Auret, and give him all the help I could, to heal him of his wound. I told him I would employ all the little knowledge it had pleased God to give me. I went off, escorted by two gentlemen, to the Chateau d' Auret, which is a league and a half from Mons in Hainault, where M. le Marquis was lying. So soon as I had come, I visited him, and told him the King had commanded me to come and see him and dress his wound. He said he was very glad I had come, and was much beholden to the King, who had done him so much honour as to send me to him. I found him in a high fever, his eyes deep sunken, with a moribund and yellowish face, his tongue dry and parched, and the whole body much wasted and lean, the voice low as of a man very near death: and I found his thigh much inflamed, suppurating, and ulcerated, discharging a greenish and very offensive sanies. I probed it with a silver probe, wherewith I found a large cavity in the middle of the thigh, and others round the knee, sanious and cuniculate: also several scales of bone, some loose, others not. The leg was greatly swelled, and imbued with a pituitous humor ... and bent and drawn back. There was a large bedsore; he could rest neither day nor night; and had no appetite to eat, but very thirsty. I was told he often fell into a faintness of the heart, and sometimes as in epilepsy: and often he felt sick, with such trembling he could not carry his hands to his mouth. Seeing and considering all these great complications, and the vital powers thus broken down, truly I was very sorry I had come to him, because it seemed to me there was little hope he would escape death. All the same, to give him courage and good hope, I told him I would soon set him on his legs, by the grace of God, and the help of his physicians and surgeons. Having seen him, I went a walk in a garden, and prayed God He would show me this grace, that he should recover; and that He would bless our hands and our medicaments, to fight such a complication of diseases. I discussed in my mind the means I must take to do this. They called me to dinner. I came into the kitchen, and there I saw, taken out of a great pot, half a sheep, a quarter of veal, three great pieces of beef, two fowls, and a very big piece of bacon, with abundance of good herbs: then I said to myself that the broth of the pot would be full of juices, and very nourishing. After dinner, we began our consultation, all the physicians and surgeons together, in the presence of M. le Duc d' Ascot and some gentlemen who were with him. I began to say to the surgeons that I was astonished they had not made incisions in M. le Marquis' thigh, seeing that it was all suppurating, and the thick matter in it very foetid and offensive, showing it had long been pent up there; and that I had found with the probe caries of the bone, and scales of bone, which were already loose. They answered me: "Never would he consent to it"; indeed, it was near two months since they had been able to get leave to put clean sheets on his bed; and one scarce dared touch the coverlet, so great was his pain. Then I said, "To heal him, we must touch something else than the coverlet of his bed." Each said what he thought of the malady of the patient, and in conclusion they all held it hopeless. I told them there was still some hope, because he was young, and God and Nature sometimes do things which seem to physicians and surgeons impossible. To restore the warmth and nourishment of the body, general frictions must be made with hot cloths, above, below, to right, to left, and around, to draw the blood and the vital spirits from within outward. ... For the bedsore, he must be put in a fresh, soft bed, with clean shirt and sheets... Having discoursed of the causes and complications of his malady, I said we must cure them by their contraries; and must first ease the pain, making openings in the thigh to let out the matter. ... Secondly, having regard to the great swelling and coldness of the limb, we must apply hot bricks round it, and sprinkle them with a decoction of nerval herbs in wine and vinegar, and wrap them in napkins; and to his feet, an earthenware bottle filled with the decoction, corked, and wrapped in cloths. Then the thigh, and the whole of the leg, must be fomented with a decoction made of sage, rosemary, thyme, lavender, flowers of chamomile and melilot, red roses boiled in white wine, with a drying powder made of oak-- ashes and a little vinegar and half a handful of salt. ... Thirdly, we must apply to the bedsore a large plaster made of the desiccative red ointment and of Unguentum Comitissoe, equal parts, mixed together, to ease his pain and dry the ulcer; and he must have a little pillow of down, to keep all pressure off it. ... And for the strengthening of his heart, we must apply over it a refrigerant of oil of waterlilies, ointment of roses, and a little saffron, dissolved in rose-vinegar and treacle, spread on a piece of red cloth. For the syncope, from exhaustion of the natural forces, troubling the brain, he must have good nourishment full of juices, as raw eggs, plums stewed in wine and sugar, broth of the meat of the great pot, whereof I have already spoken; the white meat of fowls, partridges' wings minced small, and other roast meats easy to digest, as veal, kid, pigeons, partridges, thrushes, and the like, with sauce of orange, verjuice, sorrel, sharp pomegranates; or he may have them boiled with good herbs, as lettuce, purslain, chicory, bugloss, marigold, and the like. At night he can take barley-water, with juice of sorrel and of waterlilies, of each two ounces, with four or five grains of opium, and the four cold seeds crushed, of each half an ounce; which is a good nourishing remedy and will make him sleep. His bread to be farmhouse bread, neither too stale nor too fresh. For the great pain in his head, his hair must be cut, and his head rubbed with rose-vinegar just warm, and a double cloth steeped in it and put there; also a forehead-cloth, of oil of roses and water-lilies and poppies, and a little opium and rose-vinegar, with a little camphor, and changed from time to time. Moreover, we must allow him to smell flowers of henbane and water-lilies, bruised with vinegar and rose-water, with a little camphor, all wrapped in a handkerchief, to be held some time to his nose. ... And we must make artificial rain, pouring water from some high place into a cauldron, that he may hear the sound of it; by which means sleep shall be provoked on him. As for the contraction of his leg, there is hope of righting it when we have let out the pus and other humors pent up in the thigh, and have rubbed the whole knee with ointment of mallows, and oil of lilies, and a little eau-de-vie, and wrapped it in black wool with the grease left in it; and if we put under the knee a feather pillow doubled, little by little we shall straighten the leg. This my discourse was well approved by the physicians and surgeons. The consultation ended, we went back to the patient, and I made three openings in his thigh. ... Two or three hours later, I got a bed made near his old one, with fair white sheets on it; then a strong man put him in it, and he was thankful to be taken out of his foul stinking bed. Soon after, he asked to sleep; which he did for near four hours; and everybody in the house began to feel happy, and especially M. le Duc d' Ascot, his brother. The following days, I made injections, into the depth and cavities of the ulcers, of Aegyptiacum dissolved sometimes in eau-de-vie, other times in wine, I applied compresses to the bottom of the sinuous tracks, to cleanse and dry the soft spongy flesh, and hollow leaden tents, that the sanies might always have a way out; and above them a large plaster of Diacalcitheos dissolved in wine. And I bandaged him so skilfully that he had no pain; and when the pain was gone, the fever began at once to abate. Then I gave him wine to drink moderately tempered with water, knowing it would restore and quicken the vital forces. And all that we agreed in consultation was done in due time and order; and so soon as his pains and fever ceased, he began steadily to amend. He dismissed two of his surgeons, and one of his physicians, so that we were but three with him. Now I stopped there about two months, not without seeing many patients, both rich and poor, who came to me from three or four leagues round. He gave food and drink to the needy, and commended them all to me, asking me to help them for his sake. I protest I refused not one, and did for them all I could, to his great pleasure. Then, when I saw him beginning to be well, I told him we must have viols and violins, and a buffoon to make him laugh: which he did. In one month, we got him into a chair, and he had himself carried about in his garden and at the door of his chateau, to see everybody passing by. The villagers of two or three leagues round, now they could have sight of him, came on holidays to sing and dance, men and women, pell-mell for a frolic, rejoiced at his good convalescence, all glad to see him, not without plenty of laughter and plenty to drink. He always gave them a hogshead of beer; and they all drank merrily to his health. And the citizens of Mons in Hainault, and other gentlemen, his neighbours, came to see him for the wonder of it, as a man come out of the grave; and from the time he was well, he was never without company. When one went out, another came in to visit him; his table was always well covered. He was dearly loved both by the nobility and by the common people; as for his generosity, so for his handsome face and his courtesy: with a kind look and a gracious word for everybody, so that all who saw him had perforce to love him. The chief citizens of Mons came one Saturday, to beg him let me go to Mons, where they wished to entertain me with a banquet, for their love of him. He told them he would urge me to go, which he did; but I said such great honour was not for me, moreover they could not feast me better than he did. Again he urged me, with much affection, to go there, to please him; and I agreed. The next day, they came to fetch me with two carriages: and when we got to Mons, we found the dinner ready, and the chief men of the town, with their ladies, who attended me with great devotion. We sat down to dinner, and they put me at the top of the table, and all drank to me, and to the health of M. le Marquis d'Auret: saying he was happy, and they with him, to have had me to put him on his legs again; and truly the whole company were full of honour and love for him. After dinner, they brought me back to the Chateau d'Auret, where M. le Marquis was awaiting me; who affectionately welcomed me, and would hear what we had done at our banquet; and I told him all the company had drunk many times to his health. In six weeks he began to stand a little on crutches, and to put on fat and get a good natural colour. He would go to Beaumont, his brother's place; and was taken there in a carrying-chair, by eight men at a time. And the peasants in the villages through which we passed, knowing it was M. le Marquis, fought who should carry him, and would have us drink with them; but it was only beer. Yet I believe if they had possessed wine, even hippocras, they would have given it to us with a will. And all were right glad to see him, and all prayed God for him. When we came to Beaumont, everybody came out to meet us and pay their respects to him, and prayed God bless him and keep him in good health. We came to the chateau, and found there more than fifty gentlemen whom M. le Duc d'Ascot had invited to come and be happy with his brother; and he kept open house three whole days. After dinner, the gentlemen used to tilt at the ring and play with the foils, and were full of joy at the sight of M. d'Auret, for they had heard he would never leave his bed or be healed of his wound. I was always at the upper end of the table, and everybody drank to him and to me, thinking to make me drunk, which they could not; for I drank only as I always do. A few days later, we went back; and I took my leave of Mdme. la Duchesse d'Ascot, who drew a diamond from her finger, and gave it me in gratitude for my good care of her brother: and the diamond was worth more than fifty crowns. M. d'Auret was ever getting better, and was walking all alone on crutches round his garden. Many times I asked him to let me go back to Paris, telling him his physician and his surgeon could do all that was now wanted for his wound: and to make a beginning to get away from him, I asked him to let me go and see the town of Antwerp. To this he agreed at once, and told his steward to escort me there, with two pages. We passed through Malines and Brussels, where the chief citizens of the town begged us to let them know of it when we returned; for they too wished, like those of Mons, to have a festival for me. I gave them very humble thanks, saying I did not deserve such honour. I was two days and a half seeing the town of Antwerp, where certain merchants, knowing the steward, prayed he would let them have the honour of giving us a dinner or a supper: it was who should have us, and they were all truly glad to hear how well M. d' Auret was doing, and made more of me than I asked. On my return, I found M. le Marquis enjoying himself: and five or six days later I asked his leave to go, which he gave, said he, with great regret. And he made me a handsome present of great value, and sent me back, with the steward, and two pages, to my house in Paris. I forgot to say that the Spaniards have since ruined and demolished his Chateau d' Auret, sacked, pillaged, and burned all the houses and villages belonging to him: because he would not be of their wicked party in their assassinations and ruin of the Netherlands. I have published this Apologia, that all men may know on what footing I have always gone: and sure there is no man so touchy not to take in good part what I have said. For I have but told the truth; and the purport of my discourse is plain for all men to see, and the facts themselves are my guarantee against all calumnies. ON THE MOTION OF THE HEART AND BLOOD IN ANIMALS BY WILLIAM HARVEY TRANSLATED BY ROBERT WILLIS AND REVISED BY ALEXANDER BOWIE INTRODUCTORY NOTE William Harvey, whose epoch-making treatise announcing and demonstrating the ejaculation of the blood is here printed, was born at Folkestone, Kent, England, April 1, 1578. He was educated at the King's School, Canterbury, and at Gonville and Caius College, Cambridge; and studied medicine on the Continent, receiving the degree of M.D. from the University of Padua. He took the same degree later at both the English universities. After his return to England he became Fellow of the College of Physicians, physician to St. Bartholomew's Hospital, and Lumleian lecturer at the College of Physicians. It was in this last capacity that he delivered, in 1616, the lectures in which he first gave public notice of his theories on the circulation of the blood. The notes of these lectures are still preserved in the British Museum. In 1618 Harvey was appointed physician extraordinary to James I, and he remained in close professional relations to the royal family until the close of the Civil War, being present at the battle of Edgehill. By mandate of Charles I, he was, for a short time, Warden of Merton College, Oxford (1645-6), and, when he was too infirm to undertake the duties, he was offered the Presidency of the College of Physicians. He died on June 3, 1657. Harvey's famous "Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus" was published in Latin at Frankfort in 1628. The discovery was received with great interest, and in his own country was accepted at once; on the Continent it won favor more slowly. Before his death, however, the soundness of his views was acknowledged by the medical profession throughout Europe, and "it remains to this day the greatest of the discoveries of physiology, and its whole honor belongs to Harvey." DEDICATION TO HIS VERY DEAR FRIEND, DOCTOR ARGENT, THE EXCELLENT AND ACCOMPLISHED PRESIDENT OF THE ROYAL COLLEGE OF PHYSICIANS, AND TO OTHER LEARNED PHYSICIANS, HIS MOST ESTEEMED COLLEAGUES. I have already and repeatedly presented you, my learned friends, with my new views of the motion and function of the heart, in my anatomical lectures; but having now for more than nine years confirmed these views by multiplied demonstrations in your presence, illustrated them by arguments, and freed them from the objections of the most learned and skilful anatomists, I at length yield to the requests, I might say entreaties, of many, and here present them for general consideration in this treatise. Were not the work indeed presented through you, my learned friends, I should scarce hope that it could come out scatheless and complete; for you have in general been the faithful witnesses of almost all the instances from which I have either collected the truth or confuted error. You have seen my dissections, and at my demonstrations of all that I maintain to be objects of sense, you have been accustomed to stand by and bear me out with your testimony. And as this book alone declares the blood to course and revolve by a new route, very different from the ancient and beaten pathway trodden for so many ages, and illustrated by such a host of learned and distinguished men, I was greatly afraid lest I might be charged with presumption did I lay my work before the public at home, or send it beyond seas for impression, unless I had first proposed the subject to you, had confirmed its conclusions by ocular demonstrations in your presence, had replied to your doubts and objections, and secured the assent and support of our distinguished President. For I was most intimately persuaded, that if I could make good my proposition before you and our College, illustrious by its numerous body of learned individuals, I had less to fear from others. I even ventured to hope that I should have the comfort of finding all that you granted me in your sheer love of truth, conceded by others who were philosophers like yourselves. True philosophers, who are only eager for truth and knowledge, never regard themselves as already so thoroughly informed, but that they welcome further information from whomsoever and from wheresoever it may come; nor are they so narrow-minded as to imagine any of the arts or sciences transmitted to us by the ancients, in such a state of forwardness or completeness, that nothing is left for the ingenuity and industry of others. On the contrary, very many maintain that all we know is still infinitely less than all that still remains unknown; nor do philosophers pin their faith to others' precepts in such wise that they lose their liberty, and cease to give credence to the conclusions of their proper senses. Neither do they swear such fealty to their mistress Antiquity, that they openly, and in sight of all, deny and desert their friend Truth. But even as they see that the credulous and vain are disposed at the first blush to accept and believe everything that is proposed to them, so do they observe that the dull and unintellectual are indisposed to see what lies before their eyes, and even deny the light of the noonday sun. They teach us in our course of philosophy to sedulously avoid the fables of the poets and the fancies of the vulgar, as the false conclusions of the sceptics. And then the studious and good and true, never suffer their minds to be warped by the passions of hatred and envy, which unfit men duly to weigh the arguments that are advanced in behalf of truth, or to appreciate the proposition that is even fairly demonstrated. Neither do they think it unworthy of them to change their opinion if truth and undoubted demonstration require them to do so. They do not esteem it discreditable to desert error, though sanctioned by the highest antiquity, for they know full well that to err, to be deceived, is human; that many things are discovered by accident and that many may be learned indifferently from any quarter, by an old man from a youth, by a person of understanding from one of inferior capacity. My dear colleagues, I had no purpose to swell this treatise into a large volume by quoting the names and writings of anatomists, or to make a parade of the strength of my memory, the extent of my reading, and the amount of my pains; because I profess both to learn and to teach anatomy, not from books but from dissections; not from the positions of philosophers but from the fabric of nature; and then because I do not think it right or proper to strive to take from the ancients any honor that is their due, nor yet to dispute with the moderns, and enter into controversy with those who have excelled in anatomy and been my teachers. I would not charge with wilful falsehood any one who was sincerely anxious for truth, nor lay it to any one's door as a crime that he had fallen into error. I avow myself the partisan of truth alone; and I can indeed say that I have used all my endeavours, bestowed all my pains on an attempt to produce something that should be agreeable to the good, profitable to the learned, and useful to letters. Farewell, most worthy Doctors, And think kindly of your Anatomist, WILLIAM HARVEY. INTRODUCTION As we are about to discuss the motion, action, and use of the heart and arteries, it is imperative on us first to state what has been thought of these things by others in their writings, and what has been held by the vulgar and by tradition, in order that what is true may be confirmed, and what is false set right by dissection, multiplied experience, and accurate observation. Almost all anatomists, physicians, and philosophers up to the present time have supposed, with Galen, that the object of the pulse was the same as that of respiration, and only differed in one particular, this being conceived to depend on the animal, the respiration on the vital faculty; the two, in all other respects, whether with reference to purpose or to motion, comporting themselves alike. Whence it is affirmed, as by Hieronymus Fabricius of Aquapendente, in his book on "Respiration," which has lately appeared, that as the pulsation of the heart and arteries does not suffice for the ventilation and refrigeration of the blood, therefore were the lungs fashioned to surround the heart. From this it appears that whatever has hitherto been said upon the systole and diastole, or on the motion of the heart and arteries, has been said with especial reference to the lungs. But as the structure and movements of the heart differ from those of the lungs, and the motions of the arteries from those of the chest, so it seems likely that other ends and offices will thence arise, and that the pulsations and uses of the heart, likewise of the arteries, will differ in many respects from the heavings and uses of the chest and lungs. For did the arterial pulse and the respiration serve the same ends; did the arteries in their diastole take air into their cavities, as commonly stated, and in their systole emit fuliginous vapours by the same pores of the flesh and skin; and further, did they, in the time intermediate between the diastole and the systole, contain air, and at all times either air or spirits, or fuliginous vapours, what should then be said to Galen, who wrote a book on purpose to show that by nature the arteries contained blood, and nothing but blood, and consequently neither spirits nor air, as may readily be gathered from the experiments and reasonings contained in the same book? Now, if the arteries are filled in the diastole with air then taken into them (a larger quantity of air penetrating when the pulse is large and full), it must come to pass that if you plunge into a bath of water or of oil when the pulse is strong and full, it ought forthwith to become either smaller or much slower, since the circumambient bath will render it either difficult or impossible for the air to penetrate. In like manner, as all the arteries, those that are deep-seated as well as those that are superficial, are dilated at the same instant and with the same rapidity, how is it possible that air should penetrate to the deeper parts as freely and quickly through the skin, flesh, and other structures, as through the cuticle alone? And how should the arteries of the foetus draw air into their cavities through the abdomen of the mother and the body of the womb? And how should seals, whales, dolphins, and other cetaceans, and fishes of every description, living in the depths of the sea, take in and emit air by the diastole and systole of their arteries through the infinite mass of water? For to say that they absorb the air that is present in the water, and emit their fumes into this medium, were to utter something like a figment. And if the arteries in their systole expel fuliginous vapours from their cavities through the pores of the flesh and skin, why not the spirits, which are said to be contained in those vessels, at the same time, since spirits are much more subtile than fuliginous vapours or smoke? And if the arteries take in and cast out air in the systole and diastole, like the lungs in the process of respiration, why do they not do the same thing when a wound is made in one of them, as in the operation of arteriotomy? When the windpipe is divided, it is sufficiently obvious that the air enters and returns through the wound by two opposite movements; but when an artery is divided, it is equally manifest that blood escapes in one continuous stream, and that no air either enters or issues. If the pulsations of the arteries fan and refrigerate the several parts of the body as the lungs do the heart, how comes it, as is commonly said, that the arteries carry the vital blood into the different parts, abundantly charged with vital spirits, which cherish the heat of these parts, sustain them when asleep, and recruit them when exhausted? How should it happen that, if you tie the arteries, immediately the parts not only become torpid, and frigid, and look pale, but at length cease even to be nourished? This, according to Galen, is because they are deprived of the heat which flowed through all parts from the heart, as its source; whence it would appear that the arteries rather carry warmth to the parts than serve for any fanning or refrigeration. Besides, how can their diastole draw spirits from the heart to warm the body and its parts, and means of cooling them from without? Still further, although some affirm that the lungs, arteries, and heart have all the same offices, they yet maintain that the heart is the workshop of the spirits, and that the arteries contain and transmit them; denying, however, in opposition to the opinion of Columbus, that the lungs can either make or contain spirits. They then assert, with Galen, against Erasistratus, that it is the blood, not spirits, which is contained in the arteries. These opinions are seen to be so incongruous and mutually subversive, that every one of them is justly brought under suspicion. That it is blood and blood alone which is contained in the arteries is made manifest by the experiment of Galen, by arteriotomy, and by wounds; for from a single divided artery, as Galen himself affirms in more than one place, the whole of the blood may be withdrawn in the course of half an hour or less. The experiment of Galen alluded to is this: "If you include a portion of an artery between two ligatures, and slit it open lengthwise you will find nothing but blood"; and thus he proves that the arteries contain only blood. And we too may be permitted to proceed by a like train of reasoning: if we find the same blood in the arteries as in the veins, after having tied them in the same way, as I have myself repeatedly ascertained, both in the dead body and in living animals, we may fairly conclude that the arteries contain the same blood as the veins, and nothing but the same blood. Some, whilst they attempt to lessen the difficulty, affirm that the blood is spirituous and arterious, and virtually concede that the office of the arteries is to carry blood from the heart into the whole of the body, and that they are therefore filled with blood; for spirituous blood is not the less blood on that account. And no one denies the blood as such, even the portion of it which flows in the veins, is imbued with spirits. But if that portion of it which is contained in the arteries be richer in spirits, it is still to be believed that these spirits are inseparable from the blood, like those in the veins; that the blood and spirits constitute one body (like whey and butter in milk, or heat in hot water), with which the arteries are charged, and for the distribution of which from the heart they are provided. This body is nothing else than blood. But if this blood be said to be drawn from the heart into the arteries by the diastole of these vessels, it is then assumed that the arteries by their distension are filled with blood, and not with the surrounding air, as heretofore; for if they be said also to become filled with air from the ambient atmosphere, how and when, I ask, can they receive blood from the heart? If it be answered: during the systole, I take it to be impossible: the arteries would then have to fill while they contracted, to fill, and yet not become distended. But if it be said: during diastole, they would then, and for two opposite purposes, be receiving both blood and air, and heat and cold, which is improbable. Further when it is affirmed that the diastole of the heart and arteries is simultaneous, and the systole of the two is also concurrent, there is another incongruity. For how can two bodies mutually connected, which are simultaneously distended, attract or draw anything from one another? or being simultaneously contracted, receive anything from each other? And then it seems impossible that one body can thus attract another body into itself, so as to become distended, seeing that to be distended is to be passive, unless, in the manner of a sponge, which has been previously compressed by an external force, it is returning to its natural state. But it is difficult to conceive that there can be anything of this kind in the arteries. The arteries dilate, because they are filled like bladders or leathern bottles; they are not filled because they expand like bellows. This I think easy of demonstration, and indeed conceive that I have already proved it. Nevertheless, in that book of Galen headed "Quod Sanguis continetur in Arterus," he quotes an experiment to prove the contrary. An artery having been exposed, is opened longitudinally, and a reed or other pervious tube is inserted into the vessel through the opening, by which the blood is prevented from being lost, and the wound is closed. "So long," he says, "as things are thus arranged, the whole artery will pulsate; but if you now throw a ligature about the vessel and tightly compress its wall over the tube, you will no longer see the artery beating beyond the ligature." I have never performed this experiment of Galen's nor do I think that it could very well be performed in the living body, on account of the profuse flow of blood that would take place from the vessel that was operated on; neither would the tube effectually close the wound in the vessel without a ligature; and I cannot doubt but that the blood would be found to flow out between the tube and the vessel. Still Galen appears by this experiment to prove both that the pulsative property extends from the heart by the walls of the arteries, and that the arteries, whilst they dilate, are filled by that pulsific force, because they expand like bellows, and do not dilate as if they are filled like skins, But the contrary is obvious in arteriotomy and in wounds; for the blood spurting from the arteries escapes with force, now farther, now not so far, alternately, or in jets; and the jet always takes place with the diastole of the artery, never with the systole. By which it clearly appears that the artery is dilated with the impulse of the blood; for of itself it would not throw the blood to such a distance and whilst it was dilating; it ought rather to draw air into its cavity through the wound, were those things true that are commonly stated concerning the uses of the arteries. Do not let the thickness of the arterial tunics impose upon us, and lead us to conclude that the pulsative property proceeds along them from the heart For in several animals the arteries do not apparently differ from the veins; and in extreme parts of the body where the arteries are minutely subdivided, as in the brain, the hand, etc., no one could distinguish the arteries from the veins by the dissimilar characters of their coats: the tunics of both are identical. And then, in the aneurism proceeding from a wounded or eroded artery, the pulsation is precisely the same as in the other arteries, and yet it has no proper arterial covering. To this the learned Riolanus testifies along with me, in his Seventh Book. Nor let any one imagine that the uses of the pulse and the respiration are the same, because, under the influences of the same causes, such as running, anger, the warm bath, or any other heating thing, as Galen says, they become more frequent and forcible together. For not only is experience in opposition to this idea, though Galen endeavours to explain it away, when we see that with excessive repletion the pulse beats more forcibly, whilst the respiration is diminished in amount;, but in young persons the pulse is quick, whilst respiration is slow. So it is also in alarm, and amidst care, and under anxiety of mind; sometimes, too, in fevers, the pulse is rapid, but the respiration is slower than usual. These and other objections of the same kind may be urged against the opinions mentioned. Nor are the views that are entertained of the offices and pulse of the heart, perhaps, less bound up with great and most inextricable difficulties. The heart, it is vulgarly said, is the fountain and workshop of the vital spirits, the centre from which life is dispensed to the several parts of the body. Yet it is denied that the right ventricle makes spirits, which is rather held to supply nourishment to the lungs. For these reasons it is maintained that fishes are without any right ventricle (and indeed every animal wants a right ventricle which is unfurnished with lungs), and that the right ventricle is present solely for the sake of the lungs. 1. Why, I ask, when we see that the structure of both ventricles is almost identical, there being the same apparatus of fibres, and braces, and valves, and vessels, and auricles, and both in the same way in our dissections are found to be filled up with blood similarly black in colour, and coagulated--why, I say, should their uses be imagined to be different, when the action, motion, and pulse of both are the same? If the three tricuspid valves placed at the entrance into the right ventricle prove obstacles to the reflux of the blood into the vena cava, and if the three semilunar valves which are situated at the commencement of the pulmonary artery be there, that they may prevent the return of the blood into the ventricle; why, when we find similar structures in connexion with the left ventricle, should we deny that they are there for the same end, of preventing here the egress, there the regurgitation, of the blood? 2. And, when we have these structures, in points of size, form, and situation, almost in every respect the same in the left as in the right ventricle, why should it be said that things are arranged in the former for the egress and regress of spirits, and in the latter or right ventricle, for the blood? The same arrangement cannot be held fitted to favour or impede the motion of the blood and of spirits indifferently. 3. And when we observe that the passages and vessels are severally in relation to one another in point of size, viz., the pulmonary artery to the pulmonary veins; why should the one be destined to a private purpose, that of furnishing the lungs, the other to a public function? 4. And as Realdus Columbus says, is it probable that such a quantity of blood should be required for the nutrition of the lungs; the vessel that leads to them, the vena arteriosa or pulmonary artery being of greater capacity than both the iliac veins? 5. And I ask, as the lungs are so close at hand, and in continual motion, and the vessel that supplies them is of such dimensions, what is the use or meaning of this pulse of the right ventricle? and why was nature reduced to the necessity of adding another ventricle for the sole purpose of nourishing the lungs? When it is said that the left ventricle draws materials for the formation of spirits, air and blood, from the lungs and right sinuses of the heart, and in like manner sends spirituous blood into the aorta, drawing fuliginous vapours from there, and sending them by the pulmonary vein into the lungs, whence spirits are at the same time obtained for transmission into the aorta, I ask how, and by what means is the separation effected? And how comes it that spirits and fuliginous vapours can pass hither and thither without admixture or confusion? If the mitral cuspidate valves do not prevent the egress of fuliginous vapours to the lungs, how should they oppose the escape of air? And how should the semiluftars hinder the regress of spirits from the aorta upon each supervening diastole of the heart? Above all, how can they say that the spirituous blood is sent from the pulmonary veins by the left ventricle into the lungs without any obstacle to its passage from the mitral valves, when they have previously asserted that the air entered by the same vessel from the lungs into the left ventricle, and have brought forward these same mitral valves as obstacles to its retrogression? Good God! how should the mitral valves prevent the regurgitation of air and not of blood? Moreover, when they appoint the pulmonary artery, a vessel of great size, with the coverings of an artery, to none but a kind of private and single purpose, that, namely, of nourishing the lungs, why should the pulmonary vein, which is scarcely so large, which has the coats of a vein, and is soft and lax, be presumed to be made for many--three or four different--uses? For they will have it that air passes through this vessel from the lungs into the left ventricle; that fuliginous vapours escape by it from the heart into the lungs; and that a portion of the spirituous blood is distributed to the lungs for their refreshment. If they will have it that fumes and air--fumes flowing from, air proceeding towards the heart--are transmitted by the same conduit, I reply, that nature is not wont to construct but one vessel, to contrive but one way for such contrary motions and purposes, nor is anything of the kind seen elsewhere. If fumes or fuliginous vapours and air permeate this vessel, as they do the pulmonary bronchia, wherefore do we find neither air nor fuliginous vapours when we divide the pulmonary vein? Why do we always find this vessel full of sluggish blood, never of air, whilst in the lungs we find abundance of air remaining? If any one will perform Galen's experiment of dividing the trachea of a living dog, forcibly distending the lungs with a pair of bellows, and then tying the trachea securely, he will find, when he has laid open the thorax, abundance of air in the lungs, even to their extreme investing tunic, but none in either the pulmonary veins or the left ventricle of the heart. But did the heart either attract air from the lungs, or did the lungs transmit any air to the heart, in the living dog, much more ought this to be the case in the experiment just referred to. Who, indeed, doubts that, did he inflate the lungs of a subject in the dissecting--room, he would instantly see the air making its way by this route, were there actually any such passage for it? But this office of the pulmonary veins, namely, the ransference of air from the lungs of the heart, is held of such importance, that Hieronymus Fabricius of Aquapendente, contends that the lungs were made for the sake of this vessel, and that it constitutes the principal element in their structure. But I should like to be informed why, if the pulmonary vein were destined for the conveyance of air, it has the structure of a blood--vessel here. Nature had rather need of annular tubes, such as those of the bronchi in order that they might always remain open, and not be liable to collapse; and that they might continue entirely free from blood, lest the liquid should interfere with the passage of the air, as it so obviously does when the lungs labour from being either greatly oppressed or loaded in a less degree with phlegm, as they are when the breathing is performed with a sibilous or rattling noise. Still less is that opinion to be tolerated which, as a two-fold material, one aerial, one sanguineous, is required for the composition of vital spirits, supposes the blood to ooze through the septum of the heart from the right to the left ventricle by certain hidden porosities, and the air to be attracted from the lungs through the great vessel, the pulmonary vein; and which, consequently, will have it, that there are numerous porosities in the septum of the heart adapted for the transmission of the blood. But by Hercules! no such pores can be demonstrated, nor in fact do any such exist. For the septum of the heart is of a denser and more compact structure than any portion of the body, except the bones and sinews. But even supposing that there were foramina or pores in this situation, how could one of the ventricles extract anything from the other--the left, e.g., obtain blood from the right, when we see that both ventricles contract and dilate simultaneously? Why should we not rather believe that the right took spirits from the left, than that the left obtained blood from the right ventricle through these foramina? But it is certainly mysterious and incongruous that blood should be supposed to be most commodiously drawn through a set of obscure or invisible ducts, and air through perfectly open passages, at one and the same moment. And why, I ask, is recourse had to secret and invisible porosities, to uncertain and obscure channels, to explain the passage of the blood into the left ventricle, when there is so open a way through the pulmonary veins? I own it has always appeared extraordinary to me that they should have chosen to make, or rather to imagine, a way through the thick, hard, dense, and most compact septum of the heart, rather than take that by the open pulmonary vein, or even through the lax, soft and spongy substance of the lungs at large. Besides, if the blood could permeate the substance of the septum, or could be imbibed from the ventricles, what use were there for the coronary artery and vain, branches of which proceed to the septum itself, to supply it with nourishment? And what is especially worthy of notice is this: if in the foetus, where everything is more lax and soft, nature saw herself reduced to the necessity of bringing the blood from the right to the left side of the heart by the foramen ovale, from the vena cava through the pulmonary vein, how should it be likely that in the adult she should pass it so commodiously, and without an effort through the septum of the ventricles which has now become denser by age? Andreas Laurentius, [Footnote: Lib. ix, cap. xi, quest. 12.] resting on the authority of Galen [Footnote: De Locis Affectia. lib. vi, cap. 7.] and the experience of Hollerius, asserts and proves that the serum and pus in empyema, absorbed from the cavities of the chest into the pulmonary vein may be expelled and got rid of with the urine and feces through the left ventricle of the heart and arteries. He quotes the case of a certain person affected with melancholia, and who suffered from repeated fainting fits, who was relieved from the paroxysms on passing a quantity of turbid, fetid and acrid urine. But he died at last, worn out by disease; and when the body came to be opened after death, no fluid like that he had micturated was discovered either in the bladder or the kidneys; but in the left ventricle of the heart and cavity of the thorax plenty of it was met with. And then Laurentius boasts that he had predicted the cause of the symptoms. For my own part, however, I cannot but wonder, since he had divined and predicted that heterogeneous matter could be discharged by the course he indicates, why he could not or would not perceive, and inform us that, in the natural state of things, the blood might be commodiously transferred from the lungs to the left ventricle of the heart by the very same route. Since, therefore, from the foregoing considerations and many others to the same effect, it is plain that what has heretofore been said concerning the motion and function of the heart and arteries must appear obscure, inconsistent, or even impossible to him who carefully considers the entire subject, it would be proper to look more narrowly into the matter to contemplate the motion of the heart and arteries, not only in man, but in all animals that have hearts; and also, by frequent appeals to vivisection, and much ocular inspection, to investigate and discern the truth. ON THE MOTION OF THE HEART AND BLOOD IN ANIMALS CHAPTER I THE AUTHOR'S MOTIVES FOR WRITING When I first gave my mind to vivisections, as a means of discovering the motions and uses of the heart, and sought to discover these from actual inspection, and not from the writings of others, I found the task so truly arduous, so full of difficulties, that I was almost tempted to think, with Fracastorius, that the motion of the heart was only to be comprehended by God. For I could neither rightly perceive at first when the systole and when the diastole took place, nor when and where dilatation and contraction occurred, by reason of the rapidity of the motion, which in many animals is accomplished in the twinkling of an eye, coming and going like a flash of lightning; so that the systole presented itself to me now from this point, now from that; the diastole the same; and then everything was reversed, the motions occurring, as it seemed, variously and confusedly together. My mind was therefore greatly unsettled nor did I know what I should myself conclude, nor what believe from others. I was not surprised that Andreas Laurentius should have written that the motion of the heart was as perplexing as the flux and reflux of Euripus had appeared to Aristotle. At length, by using greater and daily diligence and investigation, making frequent inspection of many and various animals, and collating numerous observations, I thought that I had attained to the truth, that I should extricate myself and escape from this labyrinth, and that I had discovered what I so much desired, both the motion and the use of the heart and arteries. From that time I have not hesitated to expose my views upon these subjects, not only in private to my friends, but also in public, in my anatomical lectures, after the manner of the Academy of old. These views as usual, pleased some more, others less; some chid and calumniated me, and laid it to me as a crime that I had dared to depart from the precepts and opinions of all anatomists; others desired further explanations of the novelties, which they said were both worthy of consideration, and might perchance be found of signal use. At length, yielding to the requests of my friends, that all might be made participators in my labors, and partly moved by the envy of others, who, receiving my views with uncandid minds and understanding them indifferently, have essayed to traduce me publicly, I have moved to commit these things to the press, in order that all may be enabled to form an opinion both of me and my labours. This step I take all the more willingly, seeing that Hieronymus Fabricius of Aquapendente, although he has accurately and learnedly delineated almost every one of the several parts of animals in a special work, has left the heart alone untouched. Finally, if any use or benefit to this department of the republic of letters should accrue from my labours, it will, perhaps, be allowed that I have not lived idly, and as the old man in the comedy says: For never yet hath any one attained To such perfection, but that time, and place, And use, have brought addition to his knowledge; Or made correction, or admonished him, That he was ignorant of much which he Had thought he knew; or led him to reject What he had once esteemed of highest price. So will it, perchance, be found with reference to the heart at this time; or others, at least, starting hence, with the way pointed out to them, advancing under the guidance of a happier genius, may make occasion to proceed more fortunately, and to inquire more accurately. CHAPTER II ON THE MOTIONS OF THE HEART AS SEEN IN THE DISSECTION OF LIVING ANIMALS In the first place, then, when the chest of a living animal is laid open and the capsule that immediately surrounds the heart is slit up or removed, the organ is seen now to move, now to be at rest; there is a time when it moves, and a time when it is motionless. These things are more obvious in the colder animals, such as toads, frogs, serpents, small fishes, crabs, shrimps, snails, and shell-fish. They also become more distinct in warm-blooded animals, such as the dog and hog, if they be attentively noted when the heart begins to flag, to move more slowly, and, as it were, to die: the movements then become slower and rarer, the pauses longer, by which it is made much more easy to perceive and unravel what the motions really are, and how they are performed. In the pause, as in death, the heart is soft, flaccid, exhausted, lying, as it were, at rest. In the motion, and interval in which this is accomplished, three principal circumstances are to be noted: 1. That the heart is erected, and rises upwards to a point, so that at this time it strikes against the breast and the pulse is felt externally. 2. That it is everywhere contracted, but more especially towards the sides so that it looks narrower, relatively longer, more drawn together. The heart of an eel taken out of the body of the animal and placed upon the table or the hand, shows these particulars; but the same things are manifest in the hearts of all small fishes and of those colder animals where the organ is more conical or elongated. 3. The heart being grasped in the hand, is felt to become harder during its action. Now this hardness proceeds from tension, precisely as when the forearm is grasped, its tendons are perceived to become tense and resilient when the fingers are moved. 4. It may further be observed in fishes, and the colder blooded animals, such as frogs, serpents, etc., that the heart, when it moves, becomes of a paler color, when quiescent of a deeper blood-red color. From these particulars it appears evident to me that the motion of the heart consists in a certain universal tension--both contraction in the line of its fibres, and constriction in every sense. It becomes erect, hard, and of diminished size during its action; the motion is plainly of the same nature as that of the muscles when they contract in the line of their sinews and fibres; for the muscles, when in action, acquire vigor and tenseness, and from soft become hard, prominent, and thickened: and in the same manner the heart. We are therefore authorized to conclude that the heart, at the moment of its action, is at once constricted on all sides, rendered thicker in its parietes and smaller in its ventricles, and so made apt to project or expel its charge of blood. This, indeed, is made sufficiently manifest by the preceding fourth observation in which we have seen that the heart, by squeezing out the blood that it contains, becomes paler, and then when it sinks into repose and the ventricle is filled anew with blood, that the deeper crimson colour returns. But no one need remain in doubt of the fact, for if the ventricle be pierced the blood will be seen to be forcibly projected outwards upon each motion or pulsation when the heart is tense. These things, therefore, happen together or at the same instant: the tension of the heart, the pulse of its apex, which is felt externally by its striking against the chest, the thickening of its parietes, and the forcible expulsion of the blood it contains by the constriction of its ventricles. Hence the very opposite of the opinions commonly received appears to be true; inasmuch as it is generally believed that when the heart strikes the breast and the pulse is felt without, the heart is dilated in its ventricles and is filled with blood; but the contrary of this is the fact, and the heart, when it contracts (and the impulse of the apex is conveyed through the chest wall), is emptied. Whence the motion which is generally regarded as the diastole of the heart, is in truth its systole. And in like manner the intrinsic motion of the heart is not the diastole but the systole; neither is it in the diastole that the heart grows firm and tense, but in the systole, for then only, when tense, is it moved and made vigorous. Neither is it by any means to be allowed that the heart only moves in the lines of its straight fibres, although the great Vesalius giving this notion countenance, quotes a bundle of osiers bound in a pyramidal heap in illustration; meaning, that as the apex is approached to the base, so are the sides made to bulge out in the fashion of arches, the cavities to dilate, the ventricles to acquire the form of a cupping-glass and so to suck in the blood. But the true effect of every one of its fibres is to constringe the heart at the same time they render it tense; and this rather with the effect of thickening and amplifying the walls and substance of the organ than enlarging its ventricles. And, again, as the fibres run from the apex to the base, and draw the apex towards the base, they do not tend to make the walls of the heart bulge out in circles, but rather the contrary; inasmuch as every fibre that is circularly disposed, tends to become straight when it contracts; and is distended laterally and thickened, as in the case of muscular fibres in general, when they contract, that is, when they are shortened longitudinally, as we see them in the bellies of the muscles of the body at large. To all this let it be added, that not only are the ventricles contracted in virtue of the direction and condensation of their walls, but farther, that those fibres, or bands, styled nerves by Aristotle, which are so conspicuous in the ventricles of the larger animals, and contain all the straight fibres (the parietes of the heart containing only circular ones), when they contract simultaneously by an admirable adjustment all the internal surfaces are drawn together as if with cords, and so is the charge of blood expelled with force. Neither is it true, as vulgarly believed, that the heart by any dilatation or motion of its own, has the power of drawing the blood into the ventricles; for when it acts and becomes tense, the blood is expelled; when it relaxes and sinks together it receives the blood in the manner and wise which will by-and-by be explained. CHAPTER III OF THE MOTIONS OF THE ARTERIES, AS SEEN IN THE DISSECTION OF LIVING ANIMALS In connexion with the motions of the heart these things are further to be observed having reference to the motions and pulses of the arteries. 1. At the moment the heart contracts, and when the breast is struck, when in short the organ is in its state of systole, the arteries are dilated, yield a pulse, and are in the state of diastole. In like manner, when the right ventricle contracts and propels its charge of blood, the pulmonary artery is distended at the same time with the other arteries of the body. 2. When the left ventricle ceases to act, to contract, to pulsate, the pulse in the arteries also ceases; further, when this ventricle contracts languidly, the pulse in the arteries is scarcely perceptible. In like manner, the pulse in the right ventricle failing, the pulse in the pulmonary artery ceases also. 3. Further, when an artery is divided or punctured, the blood is seen to be forcibly propelled from the wound the moment the left ventricle contracts; and, again, when the pulmonary artery is wounded, the blood will be seen spouting forth with violence at the instant when the right ventricle contracts. So also in fishes, if the vessel which leads from the heart to the gills be divided, at the moment when the heart becomes tense and contracted, at the same moment does the blood flow with force from the divided vessel. In the same way, when we see the blood in arteriotomy projected now to a greater, now to a less distance, and that the greater jet corresponds to the diastole of the artery and to the time when the heart contracts and strikes the ribs, and is in its state of systole, we understand that the blood is expelled by the same movement. From these facts it is manifest, in opposition to commonly received opinions, that the diastole of the arteries corresponds with the time of the heart's systole; and that the arteries are filled and distended by the blood forced into them by the contraction of the ventricles; the arteries, therefore, are distended, because they are filled like sacs or bladders, and are not filled because they expand like bellows. It is in virtue of one and the same cause, therefore, that all the arteries of the body pulsate, viz., the contraction of the left ventricle; in the same way as the pulmonary artery pulsates by the contraction of the right ventricle. Finally, that the pulses of the arteries are due to the impulses of the blood from the left ventricle, may be illustrated by blowing into a glove, when the whole of the fingers will be found to become distended at one and the same time, and in their tension to bear some resemblance to the pulse. For in the ratio of the tension is the pulse of the heart, fuller, stronger, and more frequent as that acts more vigorously, still preserving the rhythm and volume, and order of the heart's contractions. Nor is it to be expected that because of the motion of the blood, the time at which the contraction of the heart takes place, and that at which the pulse in an artery (especially a distant one) is felt, shall be otherwise than simultaneous: it is here the same as in blowing up a glove or bladder; for in a plenum (as in a drum, a long piece of timber, etc.) the stroke and the motion occur at both extremities at the same time. Aristotle, [Footnote: De Anim., iii, cap. 9.] too, has said, "the blood of all animals palpitates within their veins (meaning the arteries), and by the pulse is sent everywhere simultaneously." And further, [Footnote: De Respir., cap. 20] "thus do all the veins pulsate together and by successive strokes, because they all depend upon the heart; and, as it is always in motion, so are they likewise always moving together, but by successive movements." It is well to observe with Galen, in this place, that the old philosophers called the arteries veins. I happened upon one occasion to have a particular case under my care, which plainly satisfied me of the truth: A certain person was affected with a large pulsating tumour on the right side of the neck, called an aneurism, just at that part where the artery descends into the axilla, produced by an erosion of the artery itself, and daily increasing in size; this tumour was visibly distended as it received the charge of blood brought to it by the artery, with each stroke of the heart; the connexion of parts was obvious when the body of the patient came to be opened after his death. The pulse in the corresponding arm was small, in consequence of the greater portion of the blood being diverted into the tumour and so intercepted. Whence it appears that whenever the motion of the blood through the arteries is impeded, whether it be by compression or infarction, or interception, there do the remote divisions of the arteries beat less forcibly, seeing that the pulse of the arteries is nothing more than the impulse or shock of the blood in these vessels. CHAPTER IV OF THE MOTION OF THE HEART AND ITS AURICLES, AS SEEN IN THE BODIES OF LIVING ANIMALS Besides the motions already spoken of, we have still to consider those that appertain to the auricles. Caspar Bauhin and John Riolan, [Footnote: i Bauhin, lib. ii. cap. II. Riolan. lib. viii, cap. I.] most learned men and skilful anatomists, inform us that from their observations, that if we carefully watch the movements of the heart in the vivisection of an animal, we shall perceive four motions distinct in time and in place, two of which are proper to the auricles, two to the ventricles. With all deference to such authority I say that there are four motions distinct in point of place, but not of time; for the two auricles move together, and so also do the two ventricles, in such wise that though the places be four, the times are only two. And this occurs in the following manner: There are, as it were, two motions going on together: one of the auricles, another of the ventricles; these by no means taking place simultaneously, but the motion of the auricles preceding, that of the heart following; the motion appearing to begin from the auricles and to extend to the ventricles. When all things are becoming languid, and the heart is dying, as also in fishes and the colder blooded animals there is a short pause between these two motions, so that the heart aroused, as it were, appears to respond to the motion, now more quickly, now more tardily; and at length, when near to death, it ceases to respond by its proper motion, but seems, as it were, to nod the head, and is so slightly moved that it appears rather to give signs of motion to the pulsating auricles than actually to move. The heart, therefore, ceases to pulsate sooner than the auricles, so that the auricles have been said to outlive it, the left ventricle ceasing to pulsate first of all; then its auricle, next the right ventricle; and, finally, all the other parts being at rest and dead, as Galen long since observed, the right auricle still continues to beat; life, therefore, appears to linger longest in the right auricle. Whilst the heart is gradually dying, it is sometimes seen to reply, after two or three contractions of the auricles, roused as it were to action, and making a single pulsation, slowly, unwillingly, and with an effort. But this especially is to be noted, that after the heart has ceased to beat, the auricles however still contracting, a finger placed upon the ventricles perceives the several pulsations of the auricles, precisely in the same way and for the same reason, as we have said, that the pulses of the ventricles are felt in the arteries, to wit, the distension produced by the jet of blood. And if at this time, the auricles alone pulsating, the point of the heart be cut off with a pair of scissors, you will perceive the blood flowing out upon each contraction of the auricles. Whence it is manifest that the blood enters the ventricles, not by any attraction or dilatation of the heart, but by being thrown into them by the pulses of the auricles. And here I would observe, that whenever I speak of pulsations as occurring in the auricles or ventricles, I mean contractions: first the auricles contract, and then and subsequently the heart itself contracts. When the auricles contract they are seen to become whiter, especially where they contain but little blood; but they are filled as magazines or reservoirs of the blood, which is tending spontaneously and, by its motion in the veins, under pressure towards the centre; the whiteness indicated is most conspicuous towards the extremities or edges of the auricles at the time of their contractions. In fishes and frogs, and other animals which have hearts with but a single ventricle, and for an auricle have a kind of bladder much distended with blood, at the base of the organ, you may very plainly perceive this bladder contracting first, and the contraction of the heart or ventricle following afterwards. But I think it right to describe what I have observed of an opposite character: the heart of an eel, of several fishes, and even of some (of the higher) animals taken out of the body, pulsates without auricles; nay, if it be cut in pieces the several parts may still be seen contracting and relaxing; so that in these creatures the body of the heart may be seen pulsating and palpitating, after the cessation of all motion in the auricle. But is not this perchance peculiar to animals more tenacious of life, whose radical moisture is more glutinous, or fat and sluggish, and less readily soluble? The same faculty indeed appears in the flesh of eels, which even when skinned and embowelled, and cut into pieces, are still seen to move. Experimenting with a pigeon upon one occasion, after the heart had wholly ceased to pulsate, and the auricles too had become motionless, I kept my finger wetted with saliva and warm for a short time upon the heart, and observed that under the influence of this fomentation it recovered new strength and life, so that both ventricles and auricles pulsated, contracting and relaxing alternately, recalled as it were from death to life. Besides this, however, I have occasionally observed, after the heart and even its right auricle had ceased pulsating,--when it was in articulo mortis in short,--that an obscure motion, an undulation or palpitation, remained in the blood itself, which was contained in the right auricle, this being apparent so long as it was imbued with heat and spirit. And, indeed, a circumstance of the same kind is extremely manifest in the course of the generation of animals, as may be seen in the course of the first seven days of the incubation of the chick: A drop of blood makes its appearance which palpitates, as Aristotle had already observed; from this, when the growth is further advanced and the chick is fashioned, the auricles of the heart are formed, which pulsating henceforth give constant signs of life. When at length, and after the lapse of a few days, the outline of the body begins to be distinguished, then is the ventricular part of the heart also produced, but it continues for a time white and apparently bloodless, like the rest of the animal; neither does it pulsate or give signs of motion. I have seen a similar condition of the heart in the human foetus about the beginning of the third month, the heart then being whitish and bloodless, although its auricles contained a considerable quantity of purple blood. In the same way in the egg, when the chick was formed and had increased in size, the heart too increased and acquired ventricles, which then began to receive and to transmit blood. And this leads me to remark that he who inquires very particularly into this matter will not conclude that the heart, as a whole, is the primum vivens, ultimum moriens,--the first part to live, the last to die,--but rather its auricles, or the part which corresponds to the auricles in serpents, fishes, etc., which both lives before the heart and dies after it. Nay, has not the blood itself or spirit an obscure palpitation inherent in it, which it has even appeared to me to retain after death? and it seems very questionable whether or not we are to say that life begins with the palpitation or beating of the heart. The seminal fluid of all animals--the prolific spirit, as Aristotle observed, leaves their body with a bound and like a living thing; and nature in death, as Aristotle [Footnote: De Motu Animal., cap. 8.] further remarks, retracing her steps, reverts to where she had set out, and returns at the end of her course to the goal whence she had started. As animal generation proceeds from that which is not animal, entity from nonentity, so, by a retrograde course, entity, by corruption, is resolved into nonentity, whence that in animals, which was last created, fails first and that which was first, fails last. I have also observed that almost all animals have truly a heart, not the larger creatures only, and those that have red blood, but the smaller, and pale-blooded ones also, such as slugs, snails, scallops, shrimps, crabs, crayfish, and many others; nay, even in wasps, hornets, and flies, I have, with the aid of a magnifying glass, and at the upper part of what is called the tail, both seen the heart pulsating myself, and shown it to many others. But in the pale-blooded tribes the heart pulsates sluggishly and deliberately, contracting slowly as in animals that are moribund, a fact that may readily be seen in the snail, whose heart will be found at the bottom of that orifice in the right side of the body which is seen to be opened and shut in the course of respiration, and whence saliva is discharged, the incision being made in the upper aspect of the body, near the part which corresponds to the liver. This, however, is to be observed: that in winter and the colder season, exsanguine animals, such as the snail, show no pulsation; they seem rather to live after the manner of vegetables, or of those other productions which are therefore designated plant- animals. It is also to be noted that all animals which have a heart have also auricles, or something analogous to auricles; and, further, that whenever the heart has a double ventricle, there are always two auricles present, but not otherwise. If you turn to the production of the chick in ovo, however, you will find at first no more a vesicle or auricle, or pulsating drop of blood; it is only by and by, when the development has made some progress, that the heart is fashioned; even so in certain animals not destined to attain to the highest perfection in their organization, such as bees, wasps, snails, shrimps, crayfish, etc., we only find a certain pulsating vesicle, like a sort of red or white palpitating point, as the beginning or principle of their life. We have a small shrimp in these countries, which is taken in the Thames and in the sea, the whole of whose body is transparent; this creature, placed in a little water, has frequently afforded myself and particular friends an opportunity of observing the motions of the heart with the greatest distinctness, the external parts of the body presenting no obstacle to our view, but the heart being perceived as though it had been seen through a window. I have also observed the first rudiments of the chick in the course of the fourth or fifth day of the incubation, in the guise of a little cloud, the shell having been removed and the egg immersed in clear tepid water. In the midst of the cloudlet in question there was a bloody point so small that it disappeared during the contraction and escaped the sight, but in the relaxation it reappeared again, red and like the point of a pin; so that betwixt the visible and invisible, betwixt being and not being, as it were, it gave by its pulses a kind of representation of the commencement of life. CHAPTER V OF THE MOTION, ACTION AND OFFICE OF THE HEART From these and other observations of a similar nature, I am persuaded it will be found that the motion of the heart is as follows: First of all, the auricle contracts, and in the course of its contraction forces the blood (which it contains in ample quantity as the head of the veins, the store--house and cistern of the blood) into the ventricle, which, being filled, the heart raises itself straightway, makes all its fibres tense, contracts the ventricles, and performs a beat, by which beat it immediately sends the blood supplied to it by the auricle into the arteries. The right ventricle sends its charge into the lungs by the vessel which is called vena arteriosa, but which in structure and function, and all other respects, is an artery. The left ventricle sends its charge into the aorta, and through this by the arteries to the body at large. These two motions, one of the ventricles, the other of the auricles, take place consecutively, but in such a manner that there is a kind of harmony or rhythm preserved between them, the two concurring in such wise that but one motion is apparent, especially in the warmer blooded animals, in which the movements in question are rapid. Nor is this for any other reason than it is in a piece of machinery, in which, though one wheel gives motion to another, yet all the wheels seem to move simultaneously; or in that mechanical contrivance which is adapted to firearms, where, the trigger being touched, down comes the flint, strikes against the steel, elicits a spark, which falling among the powder, ignites it, when the flame extends, enters the barrel, causes the explosion, propels the ball, and the mark is attained--all of which incidents, by reason of the celerity with which they happen, seem to take place in the twinkling of an eye. So also in deglutition: by the elevation of the root of the tongue, and the compression of the mouth, the food or drink is pushed into the fauces, when the larynx is closed by its muscles and by the epiglottis. The pharynx is then raised and opened by its muscles in the same way as a sac that is to be filled is lifted up and its mouth dilated. Upon the mouthful being received, it is forced downwards by the transverse muscles, and then carried farther by the longitudinal ones. Yet all these motions, though executed by different and distinct organs, are performed harmoniously, and in such order that they seem to constitute but a single motion and act, which we call deglutition. Even so does it come to pass with the motions and action of the heart, which constitute a kind of deglutition, a transfusion of the blood from the veins to the arteries. And if anyone, bearing these things in mind, will carefully watch the motions of the heart in the body of a living animal, he will perceive not only all the particulars I have mentioned, viz., the heart becoming erect, and making one continuous motion with its auricles; but farther, a certain obscure undulation and lateral inclination in the direction of the axis of the right ventricle, as if twisting itself slightly in performing its work. And indeed everyone may see, when a horse drinks, that the water is drawn in and transmitted to the stomach at each movement of the throat, which movement produces a sound and yields a pulse both to the ear and the touch; in the same way it is with each motion of the heart, when there is the delivery of a quantity of blood from the veins to the arteries a pulse takes place, and can be heard within the chest. The motion of the heart, then, is entirely of this description, and the one action of the heart is the transmission of the blood and its distribution, by means of the arteries, to the very extremities of the body; so that the pulse which we feel in the arteries is nothing more than the impulse of the blood derived from the heart. Whether or not the heart, besides propelling the blood, giving it motion locally, and distributing it to the body, adds anything else to it--heat, spirit, perfection,--must be inquired into by-- and--by, and decided upon other grounds. So much may suffice at this time, when it is shown that by the action of the heart the blood is transfused through the ventricles from the veins to the arteries, and distributed by them to all parts of the body. The above, indeed, is admitted by all, both from the structure of the heart and the arrangement and action of its valves. But still they are like persons purblind or groping about in the dark, for they give utterance to various, contradictory, and incoherent sentiments, delivering many things upon conjecture, as we have already shown. The grand cause of doubt and error in this subject appears to me to have been the intimate connexion between the heart and the lungs. When men saw both the pulmonary artery and the pulmonary veins losing themselves in the lungs, of course it became a puzzle to them to know how or by what means the right ventricle should distribute the blood to the body, or the left draw it from the venae cavae. This fact is borne witness to by Galen, whose words, when writing against Erasistratus in regard to the origin and use of the veins and the coction of the blood, are the following [Footnote: De Placitis Hippocratis et Platonis, vi.]: "You will reply," he says, "that the effect is so; that the blood is prepared in the liver, and is thence transferred to the heart to receive its proper form and last perfection; a statement which does not appear devoid of reason; for no great and perfect work is ever accomplished at a single effort, or receives its final polish from one instrument. But if this be actually so, then show us another vessel which draws the absolutely perfect blood from the heart, and distributes it as the arteries do the spirits over the whole body." Here then is a reasonable opinion not allowed, because, forsooth, besides not seeing the true means of transit, he could not discover the vessel which should transmit the blood from the heart to the body at large! But had anyone been there in behalf of Erasistratus, and of that opinion which we now espouse, and which Galen himself acknowledges in other respects consonant with reason, to have pointed to the aorta as the vessel which distributes the blood from the heart to the rest of the body, I wonder what would have been the answer of that most ingenious and learned man? Had he said that the artery transmits spirits and not blood, he would indeed sufficiently have answered Erasistratus, who imagined that the arteries contained nothing but spirits; but then he would have contradicted himself, and given a foul denial to that for which he had keenly contended in his writings against this very Erasistratus, to wit, that blood in substance is contained in the arteries, and not spirits; a fact which he demonstrated not only by many powerful arguments, but by experiments. But if the divine Galen will here allow, as in other places he does, "that all the arteries of the body arise from the great artery, and that this takes its origin from the heart; that all these vessels naturally contain and carry blood; that the three semilunar valves situated at the orifice of the aorta prevent the return of the blood into the heart, and that nature never connected them with this, the most noble viscus of the body, unless for some important end"; if, I say, this father of physicians concedes all these things,--and I quote his own words,--I do not see how he can deny that the great artery is the very vessel to carry the blood, when it has attained its highest term for term of perfection, from the heart for distribution to all parts of the body. Or would he perchance still hesitate, like all who have come after him, even to the present hour, because he did not perceive the route by which the blood was transferred from the veins to the arteries, in consequence, as I have already said, of the intimate connexion between the heart and the lungs? And that this difficulty puzzled anatomists not a little, when in their dissections they found the pulmonary artery and left ventricle full of thick, black, and clotted blood, plainly appears, when they felt themselves compelled to affirm that the blood made its way from the right to the left ventricle by transuding through the septum of the heart. But this fancy I have already refuted. A new pathway for the blood must therefore be prepared and thrown open, and being once exposed, no further difficulty will, I believe, be experienced by anyone in admitting what I have already proposed in regard to the pulse of the heart and arteries, viz., the passage of the blood from the veins to the arteries, and its distribution to the whole of the body by means of these vessels. CHAPTER VI OF THE COURSE BY WHICH THE BLOOD IS CARRIED FROM THE VENA CAVA INTO THE ARTERIES, OR FROM THE RIGHT INTO THE LEFT VENTRICLE OF THE HEART Since the intimate connexion of the heart with the lungs, which is apparent in the human subject, has been the probable cause of the errors that have been committed on this point, they plainly do amiss who, pretending to speak of the parts of animals generally, as anatomists for the most part do, confine their researches to the human body alone, and that when it is dead. They obviously do not act otherwise than he who, having studied the forms of a single commonwealth, should set about the composition of a general system of polity; or who, having taken cognizance of the nature of a single field, should imagine that he had mastered the science of agriculture; or who, upon the ground of one particular proposition, should proceed to draw general conclusions. Had anatomists only been as conversant with the dissection of the lower animals as they are with that of the human body, the matters that have hitherto kept them in a perplexity of doubt would, in my opinion, have met them freed from every kind of difficulty. And first, in fishes, in which the heart consists of but a single ventricle, being devoid of lungs, the thing is sufficiently manifest. Here the sac, which is situated at the base of the heart, and is the part analogous to the auricle in man, plainly forces the blood into the heart, and the heart, in its turn, conspicuously transmits it by a pipe or artery, or vessel analogous to an artery; these are facts which are confirmed by simple ocular inspection, as well as by a division of the vessel, when the blood is seen to be projected by each pulsation of the heart. The same thing is also not difficult of demonstration in those animals that have, as it were, no more than a single ventricle to the heart, such as toads, frogs, serpents, and lizards, which have lungs in a certain sense, as they have a voice. I have many observations by me on the admirable structure of the lungs of these animals, and matters appertaining, which, however, I cannot introduce in this place. Their anatomy plainly shows us that the blood is transferred in them from the veins to the arteries in the same manner as in higher animals, viz., by the action of the heart; the way, in fact, is patent, open, manifest; there is no difficulty, no room for doubt about it; for in them the matter stands precisely as it would in man were the septum of his heart perforated or removed, or one ventricle made out of two; and this being the case, I imagine that no one will doubt as to the way by which the blood may pass from the veins into the arteries. But as there are actually more animals which have no lungs than there are furnished with them, and in like manner a greater number which have only one ventricle than there are with two, it is open to us to conclude, judging from the mass or multitude of living creatures, that for the major part, and generally, there is an open way by which the blood is transmitted from the veins through the sinuses or cavities of the heart into the arteries. I have, however, cogitating with myself, seen further, that the same thing obtained most obviously in the embryos of those animals that have lungs; for in the foetus the four vessels belonging to the heart, viz., the vena cava, the pulmonary artery, the pulmonary vein, and the great artery or aorta, are all connected otherwise than in the adult, a fact sufficiently known to every anatomist. The first contact and union of the vena cava with the pulmonary veins, which occurs before the cava opens properly into the right ventricle of the heart, or gives off the coronary vein, a little above its escape from the liver, is by a lateral anastomosis; this is an ample foramen, of an oval form, communicating between the cava and the pulmonary vein, so that the blood is free to flow in the greatest abundance by that foramen from the vena cava into the pulmonary vein, and left auricle, and from thence into the left ventricle. Further, in this foramen ovale, from that part which regards the pulmonary vein, there is a thin tough membrane, larger than the opening, extended like an operculum or cover; this membrane in the adult blocking up the foramen, and adhering on all sides, finally closes it up, and almost obliterates every trace of it. In the foetus, however, this membrane is so contrived that falling loosely upon itself, it permits a ready access to the lungs and heart, yielding a passage to the blood which is streaming from the cava, and hindering the tide at the same time from flowing back into that vein. All things, in short, permit us to believe that in the embryo the blood must constantly pass by this foramen from the vena cava into the pulmonary vein, and from thence into the left auricle of the heart; and having once entered there, it can never regurgitate. Another union is that by the pulmonary artery, and is effected when that vessel divides into two branches after its escape from the right ventricle of the heart. It is as if to the two trunks already mentioned a third were superadded, a kind of arterial canal, carried obliquely from the pulmonary artery, to perforate and terminate in the great artery or aorta. So that in the dissection of the embryo, as it were, two aortas, or two roots of the great artery, appear springing from the heart. This canal shrinks gradually after birth, and after a time becomes withered, and finally almost removed, like the umbilical vessels. The arterial canal contains no membrane or valve to direct or impede the flow of blood in this or in that direction: for at the root of the pulmonary artery, of which the arterial canal is the continuation in the foetus, there are three semilunar valves, which open from within outwards, and oppose no obstacle to the blood flowing in this direction or from the right ventricle into the pulmonary artery and aorta; but they prevent all regurgitation from the aorta or pulmonic vessels back upon the right ventricle; closing with perfect accuracy, they oppose an effectual obstacle to everything of the kind in the embryo. So that there is also reason to believe that when the heart contracts, the blood is regularly propelled by the canal or passage indicated from the right ventricle into the aorta. What is commonly said in regard to these two great communications, to wit, that they exist for the nutrition of the lungs, is both improbable and inconsistent; seeing that in the adult they are closed up, abolished, and consolidated, although the lungs, by reason of their heat and motion, must then be presumed to require a larger supply of nourishment. The same may be said in regard to the assertion that the heart in the embryo does not pulsate, that it neither acts nor moves, so that nature was forced to make these communications for the nutrition of the lungs. This is plainly false; for simple inspection of the incubated egg, and of embryos just taken out of the uterus, shows that the heart moves in them precisely as in adults, and that nature feels no such necessity. I have myself repeatedly seen these motions, and Aristotle is likewise witness of their reality. "The pulse," he observes, "inheres in the very constitution of the heart, and appears from the beginning as is learned both from the dissection of living animals and the formation of the chick in the egg." [Footnote: Lib de Spiritu, cap. v.] But we further observe that the passages in question are not only pervious up to the period of birth in man, as well as in other animals, as anatomists in general have described them, but for several months subsequently, in some indeed for several years, not to say for the whole course of life; as, for example, in the goose, snipe, and various birds and many of the smaller animals. And this circumstance it was, perhaps, that imposed upon Botallus, who thought he had discovered a new passage for the blood from the vena cava into the left ventricle of the heart; and I own that when I met with the same arrangement in one of the larger members of the mouse family, in the adult state, I was myself at first led to something of a like conclusion. From this it will be understood that in the human embryo, and in the embryos of animals in which the communications are not closed, the same thing happens, namely, that the heart by its motion propels the blood by obvious and open passages from the vena cava into the aorta through the cavities of both the ventricles, the right one receiving the blood from the auricle, and propelling it by the pulmonary artery and its continuation, named the ductus arteriosus, into the aorta; the left, in like manner, charged by the contraction of its auricle, which has received its supply through the foramen ovale from the vena cava, contracting, and projecting the blood through the root of the aorta into the trunk of that vessel. In embryos, consequently, whilst the lungs are yet in a state of inaction, performing no function, subject to no motion any more than if they had not been present, nature uses the two ventricles of the heart as if they formed but one, for the transmission of the blood. The condition of the embryos of those animals which have lungs, whilst these organs are yet in abeyance and not employed, is the same as that of those animals which have no lungs. So it clearly appears in the case of the foetus that the heart by its action transfers the blood from the vena cava into the aorta, and that by a route as obvious and open, as if in the adult the two ventricles were made to communicate by the removal of their septum. We therefore find that in the greater number of animals-- in all, indeed, at a certain period of their existence--the channels for the transmission of the blood through the heart are conspicuous. But we have to inquire why in some creatures--those, namely, that have warm blood, and that have attained to the adult age, man among the number--we should not conclude that the same thing is accomplished through the substance of the lungs, which in the embryo, and at a time when the function of these organs is in abeyance, nature effects by the direct passages described, and which, indeed, she seems compelled to adopt through want of a passage by the lungs; or why it should be better (for nature always does that which is best) that she should close up the various open routes which she had formerly made use of in the embryo and foetus, and still uses in all other animals. Not only does she thereby open up no new apparent channels for the passages of the blood, but she even shuts up those which formerly existed. And now the discussion is brought to this point, that they who inquire into the ways by which the blood reaches the left ventricle of the heart: and pulmonary veins from the vena cava, will pursue the wisest course if they seek by dissection to discover the causes why in the larger and more perfect animals of mature age nature has rather chosen to make the blood percolate the parenchyma of the lungs, than, as in other instances, chosen a direct and obvious course--for I assume that no other path or mode of transit can be entertained. It must be because the larger and more perfect animals are warmer, and when adult their heat greater--ignited, as I might say, and requiring to be damped or mitigated, that the blood is sent through the lungs, in order that it may be tempered by the air that is inspired, and prevented from boiling up, and so becoming extinguished, or something else of the sort. But to determine these matters, and explain them satisfactorily, were to enter on a speculation in regard to the office of the lungs and the ends for which they exist. Upon such a subject, as well as upon what pertains to respiration, to the necessity and use of the air, etc., as also to the variety and diversity of organs that exist in the bodies of animals in connexion with these matters, although I have made a vast number of observations, I shall not speak till I can more conveniently set them forth in a treatise apart, lest I should be held as wandering too wide of my present purpose, which is the use and motion of the heart, and be charged with speaking of things beside the question, and rather complicating and quitting than illustrating it. And now returning to my immediate subject, I go on with what yet remains for demonstration, viz., that in the more perfect and warmer adult animals, and man, the blood passes from the right ventricle of the heart by the pulmonary artery, into the lungs, and thence by the pulmonary veins into the left auricle, and from there into the left ventricle of the heart. And, first, I shall show that this may be so, and then I shall prove that it is so in fact. CHAPTER VII THE BLOOD PASSES THROUGH THE SUBSTANCE OF THE LUNGS FROM THE RIGHT VENTRICLE OF THE HEART INTO THE PULMONARY VEINS AND LEFT VENTRICLE That this is possible, and that there is nothing to prevent it from being so, appears when we reflect on the way in which water permeating the earth produces springs and rivulets, or when we speculate on the means by which the sweat passes through the skin, or the urine through the substance of the kidneys. It is well known that persons who use the Spa waters or those of La Madonna, in the territories of Padua, or others of an acidulous or vitriolated nature, or who simply swallow drinks by the gallon, pass all off again within an hour or two by the bladder. Such a quantity of liquid must take some short time in the concoction: it must pass through the liver (it is allowed by all that the juices of the food we consume pass twice through this organ in the course of the day); it must flow through the veins, through the tissues of the kidneys, and through the ureters into the bladder. To those, therefore, whom I hear denying that the blood, aye, the whole mass of the blood, may pass through the substance of the lungs, even as the nutritive juices percolate the liver, asserting such a proposition to be impossible, and by no means to be entertained as credible, I reply, with the poet, that they are of that race of men who, when they will, assent full readily, and when they will not, by no manner of means; who, when their assent is wanted, fear, and when it is not, fear not to give it. The substance of the liver is extremely dense, so is that of the kidney; the lungs, however, are of a much looser texture, and if compared with the kidneys are absolutely spongy. In the liver there is no forcing, no impelling power; in the lungs the blood is forced on by the pulse of the right ventricle, the necessary effect of whose impulse is the distension of the vessels and the pores of the lungs. And then the lungs, in respiration, are perpetually rising and falling: motions, the effect of which must needs be to open and shut the pores and vessels, precisely as in the case of a sponge, and of parts having a spongy structure, when they are alternately compressed and again are suffered to expand. The liver, on the contrary, remains at rest, and is never seen to be dilated or constricted. Lastly, if no one denies the possibility in man, oxen, and the larger animals generally, of the whole of the ingested juices passing through the liver, in order to reach the vena cava, for this reason, that if nourishment is to go on, these juices must needs get into the veins, and there is no other way but the one indicated, why should not the same arguments be held of avail for the passage of the blood in adults through the lungs? Why not maintain, with Columbus, that skilful and learned anatomist, that it must be so from the capacity and structure of the pulmonary vessels, and from the fact of the pulmonary veins and ventricle corresponding with them, being always found to contain blood, which must needs have come from the veins, and by no other passage save through the lungs? Columbus, and we also, from what precedes, from dissections, and other arguments, conceive the thing to be clear. But as there are some who admit nothing unless upon authority, let them learn that the truth I am contending for can be confirmed from Galen's own words, namely, that not only may the blood be transmitted from the pulmonary artery into the pulmonary veins, then into the left ventricle of the heart, and from thence into the arteries of the body, but that this is effected by the ceaseless pulsation of the heart and the motion of the lungs in breathing. There are, as everyone knows, three sigmoid or semilunar valves situated at the orifice of the pulmonary artery, which effectually prevent the blood sent into the vessel from returning into the cavity of the heart. Now Galen, explaining the use of these valves, and the necessity for them, employs the following language: [Footnote: De Usu partium, lib. vi, cap. 10] "There is everywhere a mutual anastomosis and inosculation of the arteries with the veins, and they severally transmit both blood and spirit, by certain invisible and undoubtedly very narrow passages. Now if the mouth of the pulmonary artery had stood in like manner continually open, and nature had found no contrivance for closing it when requisite, and opening it again, it would have been impossible that the blood could ever have passed by the invisible and delicate mouths, during the contractions of the thorax, into the arteries; for all things are not alike readily attracted or repelled; but that which is light is more readily drawn in, the instrument being dilated, and forced out again when it is contracted, than that which is heavy; and in like manner is anything drawn more rapidly along an ample conduit, and again driven forth, than it is through a narrow tube. But when the thorax is contracted the pulmonary veins, which are in the lungs, being driven inwardly, and powerfully compressed on every side, immediately force out some of the spirit they contain, and at the same time assume a certain portion of blood by those subtle mouths, a thing that could never come to pass were the blood at liberty to flow back into the heart through the great orifice of the pulmonary artery. But its return through this great opening being prevented, when it is compressed on every side, a certain portion of it distils into the pulmonary veins by the minute orifices mentioned." And shortly afterwards, in the next chapter, he says: "The more the thorax contracts, the more it strives to force out the blood, the more exactly do these membranes (viz., the semilunar valves) close up the mouth of the vessel, and suffer nothing to regurgitate." The same fact he has also alluded to in a preceding part of the tenth chapter: "Were there no valves, a three-fold inconvenience would result, so that the blood would then perform this lengthened course in vain; it would flow inwards during the disastoles of the lungs and fill all their arteries; but in the systoles, in the manner of the tide, it would ever and anon, like the Euripus, flow backwards and forwards by the same way, with a reciprocating motion, which would nowise suit the blood. This, however, may seem a matter of little moment: but if it meantime appear that the function of respiration suffer, then I think it would be looked upon as no trifle, etc." Shortly afterwards he says: "And then a third inconvenience, by no means to be thought lightly of, would follow, were the blood moved backwards during the expirations, had not our Maker instituted those supplementary membranes. "In the eleventh chapter he concludes: "That they (the valves) have all a common use, and that it is to prevent regurgitation or backward motion; each, however, having a proper function, the one set drawing matters from the heart, and preventing their return, the other drawing matters into the heart, and preventing their escape from it. For nature never intended to distress the heart with needless labour, neither to bring aught into the organ which it had been better to have kept away, nor to take from it again aught which it was requisite should be brought. Since, then, there are four orifices in all, two in either ventricle, one of these induces, the other educes." And again he says: "Farther, since there is one vessel, which consists of a simple covering implanted in the heart, and another which is double, extending from it (Galen is here speaking of the right side of the heart, but I extend his observations to the left side also), a kind of reservoir had to be provided, to which both belonging, the blood should be drawn in by one, and sent out by the other." Galen adduces this argument for the transit of the blood by the right ventricle from the vena cava into the lungs; but we can use it with still greater propriety, merely changing the terms, for the passage of the blood from the veins through the heart into the arteries. From Galen, however, that great man, that father of physicians, it clearly appears that the blood passes through the lungs from the pulmonary artery into the minute branches of the pulmonary veins, urged to this both by the pulses of the heart and by the motions of the lungs and thorax; that the heart, moreover, is incessantly receiving and expelling the blood by and from its ventricles, as from a magazine or cistern, and for this end it is furnished with four sets of valves, two serving for the induction and two for the eduction of the blood, lest, like the Euripus, it should be incommodiously sent hither and thither, or flow back into the cavity which it should have quitted, or quit the part where its presence was required, and so the heart might be oppressed with labour in vain, and the office of the lungs be interfered with. [Footnote: See the Commentary of the learned Hofmann upon the Sixth Book of Galen, "De Usu partium," a work which I first saw after I had written what precedes.] Finally, our position that the blood is continually permeating from the right to the left ventricle, from the vena cava into the aorta, through the porosities of the lungs, plainly appears from this, that since the blood is incessantly sent from the right ventricle into the lungs by the pulmonary artery, and in like manner is incessantly drawn from the lungs into the left ventricle, as appears from what precedes and the position of the valves, it cannot do otherwise than pass through continuously. And then, as the blood is incessantly flowing into the right ventricle of the heart, and is continually passed out from the left, as appears in like manner, and as is obvious, both to sense and reason, it is impossible that the blood can do otherwise than pass continually from the vena cava into the aorta. Dissection consequently shows distinctly what takes place in the majority of animals, and indeed in all, up to the period of their maturity; and that the same thing occurs in adults is equally certain, both from Galen's words, and what has already been said, only that in the former the transit is effected by open and obvious passages, in the latter by the hidden porosities of the lungs and the minute inosculations of vessels. It therefore appears that, although one ventricle of the heart, the left to wit, would suffice for the distribution of the blood over the body, and its eduction from the vena cava, as indeed is done in those creatures that have no lungs, nature, nevertheless, when she ordained that the same blood should also percolate the lungs, saw herself obliged to add the right ventricle, the pulse of which should force the blood from the vena cava through the lungs into the cavity of the left ventricle. In this way, it may be said, that the right ventricle is made for the sake of the lungs, and for the transmission of the blood through them, not for their nutrition; for it were unreasonable to suppose that the lungs should require so much more copious a supply of nutriment, and that of so much purer and more spirituous a nature as coming immediately from the ventricle of the heart, that either the brain, with its peculiarly pure substance, or the eyes, with their lustrous and truly admirable structure, or the flesh of the heart itself, which is more suitably nourished by the coronary artery. CHAPTER VIII OF THE QUANTITY OF BLOOD PASSING THROUGH THE HEART FROM THE VEINS TO THE ARTERIES; AND OF THE CIRCULAR MOTION OF THE BLOOD Thus far I have spoken of the passage of the blood from the veins into the arteries, and of the manner in which it is transmitted and distributed by the action of the heart; points to which some, moved either by the authority of Galen or Columbus, or the reasonings of others, will give in their adhesion. But what remains to be said upon the quantity and source of the blood which thus passes is of a character so novel and unheard-of that I not only fear injury to myself from the envy of a few, but I tremble lest I have mankind at large for my enemies, so much doth wont and custom become a second nature. Doctrine once sown strikes deep its root, and respect for antiquity influences all men. Still the die is cast, and my trust is in my love of truth and the candour of cultivated minds. And sooth to say, when I surveyed my mass of evidence, whether derived from vivisections, and my various reflections on them, or from the study of the ventricles of the heart and the vessels that enter into and issue from them, the symmetry and size of these conduits,--for nature doing nothing in vain, would never have given them so large a relative size without a purpose,--or from observing the arrangement and intimate structure of the valves in particular, and of the other parts of the heart in general, with many things besides, I frequently and seriously bethought me, and long revolved in my mind, what might be the quantity of blood which was transmitted, in how short a time its passage might be effected, and the like. But not finding it possible that this could be supplied by the juices of the ingested aliment without the veins on the one hand becoming drained, and the arteries on the other getting ruptured through the excessive charge of blood, unless the blood should somehow find its way from the arteries into the veins, and so return to the right side of the heart, I began to think whether there might not be a MOTION, AS IT WERE, IN A CIRCLE. Now, this I afterwards found to be true; and I finally saw that the blood, forced by the action of the left ventricle into the arteries, was distributed to the body at large, and its several parts, in the same manner as it is sent through the lungs, impelled by the right ventricle into the pulmonary artery, and that it: then passed through the veins and along the vena cava, and so round to the left ventricle in the manner already indicated. This motion we may be allowed to call circular, in the same way as Aristotle says that the air and the rain emulate the circular motion of the superior bodies; for the moist earth, warmed by the sun, evaporates; the vapours drawn upwards are condensed, and descending in the form of rain, moisten the earth again. By this arrangement are generations of living things produced; and in like manner are tempests and meteors engendered by the circular motion, and by the approach and recession of the sun. And similarly does it come to pass in the body, through the motion of the blood, that the various parts are nourished, cherished, quickened by the warmer, more perfect, vaporous, spirituous, and, as I may say, alimentive blood; which, on the other hand, owing to its contact with these parts, becomes cooled, coagulated, and so to speak effete. It then returns to its sovereign, the heart, as if to its source, or to the inmost home of the body, there to recover its state of excellence or perfection. Here it renews its fluidity, natural heat, and becomes powerful, fervid, a kind of treasury of life, and impregnated with spirits, it might be said with balsam. Thence it is again dispersed. All this depends on the motion and action of the heart. The heart, consequently, is the beginning of life; the sun of the microcosm, even as the sun in his turn might well be designated the heart of the world; for it is the heart by whose virtue and pulse the blood is moved, perfected, and made nutrient, and is preserved from corruption and coagulation; it is the household divinity which, discharging its function, nourishes, cherishes, quickens the whole body, and is indeed the foundation of life, the source of all action. But of these things we shall speak more opportunely when we come to speculate upon the final cause of this motion of the heart. As the blood-vessels, therefore, are the canals and agents that transport the blood, they are of two kinds, the cava and the aorta; and this not by reason of there being two sides of the body, as Aristotle has it, but because of the difference of office, not, as is commonly said, in consequence of any diversity of structure, for in many animals, as I have said, the vein does not differ from the artery in the thickness of its walls, but solely in virtue of their distinct functions and uses. A vein and an artery, both styled veins by the ancients, and that not without reason, as Galen has remarked, for the artery is the vessel which carries the blood from the heart to the body at large, the vein of the present day bringing it back from the general system to the heart; the former is the conduit from, the latter the channel to, the heart; the latter contains the cruder, effete blood, rendered unfit for nutrition; the former transmits the digested, perfect, peculiarly nutritive fluid. CHAPTER IX THAT THERE IS A CIRCULATION OF THE BLOOD IS CONFIRMED FROM THE FIRST PROPOSITION But lest anyone should say that we give them words only, and make mere specious assertions without any foundation, and desire to innovate without sufficient cause, three points present themselves for confirmation, which, being stated, I conceive that the truth I contend for will follow necessarily, and appear as a thing obvious to all. First, the blood is incessantly transmitted by the action of the heart from the vena cava to the arteries in such quantity that it cannot be supplied from the ingesta, and in such a manner that the whole must very quickly pass through the organ; second, the blood under the influence of the arterial pulse enters and is impelled in a continuous, equable, and incessant stream through every part and member of the body, in much larger quantity than were sufficient for nutrition, or than the whole mass of fluids could supply; third, the veins in like manner return this blood incessantly to the heart from parts and members of the body. These points proved, I conceive it will be manifest that the blood circulates, revolves, propelled and then returning, from the heart to the extremities, from the extremities to the heart, and thus that it performs a kind of circular motion. Let us assume, either arbitrarily or from experiment, the quantity of blood which the left ventricle of the heart will contain when distended, to be, say, two ounces, three ounces, or one ounce and a half--in the dead body I have found it to hold upwards of two ounces. Let us assume further how much less the heart will hold in the contracted than in the dilated state; and how much blood it will project into the aorta upon each contraction; and all the world allows that with the systole something is always projected, a necessary consequence demonstrated in the third chapter, and obvious from the structure of the valves; and let us suppose as approaching the truth that the fourth, or fifth, or sixth, or even but the eighth part of its charge is thrown into the artery at each contraction; this would give either half an ounce, or three drachms, or one drachm of blood as propelled by the heart at each pulse into the aorta; which quantity, by reason of the valves at the root of the vessel, can by no means return into the ventricle. Now, in the course of half an hour, the heart will have made more than one thousand beats, in some as many as two, three, and even four thousand. Multiplying the number of drachms propelled by the number of pulses, we shall have either one thousand half ounces, or one thousand times three drachms, or a like proportional quantity of blood, according to the amount which we assume as propelled with each stroke of the heart, sent from this organ into the artery--a larger quantity in every case than is contained in the whole body! In the same way, in the sheep or dog, say but a single scruple of blood passes with each stroke of the heart, in one half-hour we should have one thousand scruples, or about three pounds and a half, of blood injected into the aorta; but the body of neither animal contains above four pounds of blood, a fact which I have myself ascertained in the case of the sheep. Upon this supposition, therefore, assumed merely as a ground for reasoning, we see the whole mass of blood passing through the heart, from the veins to the arteries, and in like manner through the lungs. But let it be said that this does not take place in half an hour, but in an hour, or even in a day; any way, it is still manifest that more blood passes through the heart in consequence of its action, than can either be supplied by the whole of the ingesta, or than can be contained in the veins at the same moment. Nor can it be allowed that the heart in contracting sometimes propels and sometimes does not propel, or at most propels but very little, a mere nothing, or an imaginary something: all this, indeed, has already been refuted, and is, besides, contrary both to sense and reason. For if it be a necessary effect of the dilatation of the heart that its ventricles become filled with blood, it is equally so that, contracting, these cavities should expel their contents; and this not in any trifling measure. For neither are the conduits small, nor the contractions few in number, but frequent, and always in some certain proportion, whether it be a third or a sixth, or an eighth, to the total capacity of the ventricles, so that a like proportion of blood must be expelled, and a like proportion received with each stroke of the heart, the capacity of the ventricle contracted always bearing a certain relation to the capacity of the ventricle when dilated. And since, in dilating, the ventricles cannot be supposed to get filled with nothing, or with an imaginary something, so in contracting they never expel nothing or aught imaginary, but always a certain something, viz., blood, in proportion to the amount of the contraction. Whence it is to be concluded that if at one stroke the heart of man, the ox, or the sheep, ejects but a single drachm of blood and there are one thousand strokes in half an hour, in this interval there will have been ten pounds five ounces expelled; if with each stroke two drachms are expelled, the quantity would, of course, amount to twenty pounds and ten ounces; if half an ounce, the quantity would come to forty-one pounds and eight ounces; and were there one ounce, it would be as much as eighty-three pounds and four ounces; the whole of which, in the course of one-half hour, would have been transfused from the veins to the arteries. The actual quantity of blood expelled at each stroke of the heart, and the circumstances under which it is either greater or less than ordinary, I leave for particular determination afterwards, from numerous observations which I have made on the subject. Meantime this much I know, and would here proclaim to all, that the blood is transfused at one time in larger, at another in smaller, quantity; and that the circuit of the blood is accomplished now more rapidly, now more slowly, according to the temperament, age, etc., of the individual, to external and internal circumstances, to naturals and non-naturals--sleep, rest, food, exercise, affections of the mind, and the like. But, supposing even the smallest quantity of blood to be passed through the heart and the lungs with each pulsation, a vastly greater amount would still be thrown into the arteries and whole body than could by any possibility be supplied by the food consumed. It could be furnished in no other way than by making a circuit and returning. This truth, indeed, presents itself obviously before us when we consider what happens in the dissection of living animals; the great artery need not be divided, but a very small branch only (as Galen even proves in regard to man), to have the whole of the blood in the body, as well that of the veins as of the arteries, drained away in the course of no long time--some half-hour or less. Butchers are well aware of the fact and can bear witness to it; for, cutting the throat of an ox and so dividing the vessels of the neck, in less than a quarter of an hour they have all the vessels bloodless--the whole mass of blood has escaped. The same thing also occasionally occurs with great rapidity in performing amputations and removing tumors in the human subject. Nor would this argument lose of its force, did any one say that in killing animals in the shambles, and performing amputations, the blood escaped in equal, if not perchance in larger quantity by the veins than by the arteries. The contrary of this statement, indeed, is certainly the truth; the veins, in fact, collapsing, and being without any propelling power, and further, because of the impediment of the valves, as I shall show immediately, pour out but very little blood; whilst the arteries spout it forth with force abundantly, impetuously, and as if it were propelled by a syringe. And then the experiment is easily tried of leaving the vein untouched and only dividing the artery in the neck of a sheep or dog, when it will be seen with what force, in what abundance, and how quickly, the whole blood in the body, of the veins as well as of the arteries, is emptied. But the arteries receive blood from the veins in no other way than by transmission through the heart, as we have already seen; so that if the aorta be tied at the base of the heart, and the carotid or any other artery be opened, no one will now be surprised to find it empty, and the veins only replete with blood. And now the cause is manifest, why in our dissections we usually find so large a quantity of blood in the veins, so little in the arteries; why there is much in the right ventricle, little in the left, which probably led the ancients to believe that the arteries (as their name implies) contained nothing but spirits during the life of an animal. The true cause of the difference is perhaps this, that as there is no passage to the arteries, save through the lungs and heart, when an animal has ceased to breathe and the lungs to move, the blood in the pulmonary artery is prevented from passing into the pulmonary veins, and from thence into the left ventricle of the heart; just as we have already seen the same transit prevented in the embryo, by the want of movement in the lungs and the alternate opening, and shutting of their hidden and invisible porosities and apertures. But the heart not ceasing to act at the same precise moment as the lungs, but surviving them and continuing to pulsate for a time, the left ventricle and arteries go on distributing their blood to the body at large and sending it into the veins; receiving none from the lungs, however, they are soon exhausted, and left, as it were, empty. But even this fact confirms our views, in no trifling manner, seeing that it can be ascribed to no other than the cause we have just assumed. Moreover, it appears from this that the more frequently or forcibly the arteries pulsate, the more speedily will the body be exhausted of its blood during hemorrhage. Hence, also, it happens, that in fainting fits and in states of alarm, when the heart beats more languidly and less forcibly, hemorrhages are diminished and arrested. Still further, it is from this, that after death, when the heart has ceased to beat, it is impossible, by dividing either the jugular or femoral veins and arteries, by any effort, to force out more than one-half of the whole mass of the blood. Neither could the butchers ever bleed the carcass effectually did he neglect to cut the throat of the ox which he has knocked on the head and stunned, before the heart had ceased beating. Finally, we are now in a condition to suspect wherefore it is that no one has yet said anything to the purpose upon the anastomosis of the veins and arteries, either as to where or how it is effected, or for what purpose. I now enter upon the investigation of the subject. CHAPTER X THE FIRST POSITION: OF THE QUANTITY OF BLOOD PASSING FROM THE VEINS TO THE ARTERIES. AND THAT THERE IS A CIRCUIT OF THE BLOOD, FREED FROM OBJECTIONS, AND FARTHER CONFIRMED BY EXPERIMENT So far our first position is confirmed, whether the thing be referred to calculation or to experiment and dissection, viz., that the blood is incessantly poured into the arteries in larger quantities than it can be supplied by the food; so that the whole passing over in a short space of time, it is matter of necessity that the blood perform a circuit, that it return to whence it set out. But if anyone shall here object that a large quantity may pass through and yet no necessity be found for a circulation, that all may come from the meat and drink consumed, and quote as an illustration the abundant supply of milk in the mammae--for a cow will give three, four, and even seven gallons and more in a day, and a woman two or three pints whilst nursing a child or twins, which must manifestly be derived from the food consumed; it may be answered that the heart by computation does as much and more in the course of an hour or two. And if not yet convinced, he shall still insist that when an artery is divided, a preternatural route is, as it were, opened, and that so the blood escapes in torrents, but that the same thing does not happen in the healthy and uninjured body when no outlet is made; and that in arteries filled, or in their natural state, so large a quantity of blood cannot pass in so short a space of time as to make any return necessary--to all this it may be answered that, from the calculation already made, and the reasons assigned, it appears that by so much as the heart in its dilated state contains, in addition to its contents in the state of constriction, so much in a general way must it emit upon each pulsation, and in such quantity must the blood pass, the body being entire and naturally constituted. But in serpents, and several fishes, by tying the veins some way below the heart you will perceive a space between the ligature and the heart speedily to become empty; so that, unless you would deny the evidence of your senses, you must needs admit the return of the blood to the heart. The same thing will also plainly appear when we come to discuss our second position. Let us here conclude with a single example, confirming all that has been said, and from which everyone may obtain conviction through the testimony of his own eyes. If a live snake be laid open, the heart will be seen pulsating quietly, distinctly, for more than an hour, moving like a worm, contracting in its longitudinal dimensions, (for it is of an oblong shape), and propelling its contents. It becomes of a paler colour in the systole, of a deeper tint in the diastole; and almost all things else are seen by which I have already said that the truth I contend for is established, only that here everything takes place more slowly, and is more distinct. This point in particular may be observed more clearly than the noonday sun: the vena cava enters the heart at its lower part, the artery quits it at the superior part; the vein being now seized either with forceps or between the finger and the thumb, and the course of the blood for some space below the heart interrupted, you will perceive the part that intervenes between the fingers and the heart almost immediately to become empty, the blood being exhausted by the action of the heart; at the same time the heart will become of a much paler colour, even in its state of dilatation, than it was before; it is also smaller than at first, from wanting blood: and then it begins to beat more slowly, so that it seems at length as if it were about to die. But the impediment to the flow of blood being removed, instantly the colour and the size of the heart are restored. If, on the contrary, the artery instead of the vein be compressed or tied, you will observe the part between the obstacle and the heart, and the heart itself, to become inordinately distended, to assume a deep purple or even livid colour, and at length to be so much oppressed with blood that you will believe it about to be choked; but the obstacle removed, all things immediately return to their natural state and colour, size, and impulse. Here then we have evidence of two kinds of death: extinction from deficiency, and suffocation from excess. Examples of both have now been set before you, and you have had opportunity of viewing the truth contended for with your own eyes in the heart. CHAPTER XI THE SECOND POSITION IS DEMONSTRATED That this may the more clearly appear to everyone, I have here to cite certain experiments, from which it seems obvious that the blood enters a limb by the arteries, and returns from it by the veins; that the arteries are the vessels carrying the blood from the heart, and the veins the returning channels of the blood to the heart; that in the limbs and extreme parts of the body the blood passes either immediately by anastomosis from the arteries into the veins, or mediately by the porosities of the flesh, or in both ways, as has already been said in speaking of the passage of the blood through the lungs whence it appears manifest that in the circuit the blood moves from that place to this place, and from that point to this one; from the centre to the extremities, to wit; and from the extreme parts back to the centre. Finally, upon grounds of calculation, with the same elements as before, it will be obvious that the quantity can neither be accounted for by the ingeata, nor yet be held necessary to nutrition. The same thing will also appear in regard to ligatures, and wherefore they are said to draw; though this is neither from the heat, nor the pain, nor the vacuum they occasion, nor indeed from any other cause yet thought of; it will also explain the uses and advantages to be derived from ligatures in medicine, the principle upon which they either suppress or occasion hemorrhage; how they induce sloughing and more extensive mortification in extremities; and how they act in the castration of animals and the removal of warts and fleshy tumours. But it has come to pass, from no one having duly weighed and understood the cause and rationale of these various effects, that though almost all, upon the faith of the old writers, recommend ligatures in the treatment of disease, yet very few comprehend their proper employment, or derive any real assistance from them in effecting cures. Ligatures are either very tight or of medium tightness. A ligature I designate as tight or perfect when it so constricts an extremity that no vessel can be felt pulsating beyond it. Such a ligature we use in amputations to control the flow of blood; and such also are employed in the castration of animals and the ablation of tumours. In the latter instances, all afflux of nutriment and heat being prevented by the ligature, we see the testes and large fleshy tumours dwindle, die, and finally fall off. Ligatures of medium tightness I regard as those which compress a limb firmly all round, but short of pain, and in such a way as still suffers a certain degree of pulsation to be felt in the artery beyond them. Such a ligature is in use in blood-letting, an operation in which the fillet applied above the elbow is not drawn so tight but that the arteries at the wrist may still be felt beating under the finger. Now let anyone make an experiment upon the arm of a man, either using such a fillet as is employed in blood-letting, or grasping the limb lightly with his hand, the best subject for it being one who is lean, and who has large veins, and the best time after exercise, when the body is warm, the pulse is full, and the blood carried in larger quantity to the extremities, for all then is more conspicuous; under such circumstances let a ligature be thrown about the extremity, and drawn as tightly as can be borne, it will first be perceived that beyond the ligature, neither in the wrist nor anywhere else, do the arteries pulsate, at the same time that immediately above the ligature the artery begins to rise higher at each diastole, to throb mere violently, and to swell in its vicinity with a kind of tide, as if it strove to break through and overcome the obstacle to its current; the artery here, in short, appears as if it were preternaturally full. The hand under such circumstances retains its natural colour and appearance; in the course of time it begins to fall somewhat in temperature, indeed, but nothing is drawn into it. After the bandage has been kept on for some short time in this way, let it be slackened a little, brought to that state or term of medium tightness which is used in bleeding, and it will be seen that the whole hand and arm will instantly become deeply coloured and distended, and the veins show themselves tumid and knotted; after ten or twelve pulses of the artery, the hand will be perceived excessively distended, injected, gorged with blood, drawn, as it is said, by this medium ligature, without pain, or heat, or any horror of a vacuum, or any other cause yet indicated. If the finger be applied over the artery as it is pulsating by the edge of the fillet, at the moment of slackening it, the blood will be felt to glide through, as it were, underneath the finger; and he, too, upon whose arm the experiment is made, when the ligature is slackened, is distinctly conscious of a sensation of warmth, and of something, viz., a stream of blood suddenly making its way along the course of the vessels and diffusing itself through the hand, which at the same time begins to feel hot, and becomes distended. As we had noted, in connexion with the tight ligature, that the artery above the bandage was distended and pulsated, not below it, so, in the case of the moderately tight bandage, on the contrary, do we find that the veins below, never above, the fillet, swell, and become dilated, whilst the arteries shrink; and such is the degree of distension of the veins here, that it is only very strong pressure that will force the blood beyond the fillet, and cause any of the veins in the upper part of the arm to rise. From these facts it is easy for every careful observer to learn that the blood enters an extremity by the arteries; for when they are effectually compressed nothing is drawn to the member; the hand preserves its colour; nothing flows into it, neither is it distended; but when the pressure is diminished, as it is with the bleeding fillet, it is manifest that the blood is instantly thrown in with force, for then the hand begins to swell; which is as much as to say, that when the arteries pulsate the blood is flowing through them, as it is when the moderately tight ligature is applied; but where they do not pulsate, as, when a tight ligature is used, they cease from transmitting anything, they are only distended above the part where the ligature is applied. The veins again being compressed, nothing can flow through them; the certain indication of which is, that below the ligature they are much more tumid than above it, and than they usually appear when there is no bandage upon the arm. It therefore plainly appears that the ligature prevents the return of the blood through the veins to the parts above it, and maintains those beneath it in a state of permanent distension. But the arteries, in spite of its pressure, and under the force and impulse of the heart, send on the blood from the internal parts of the body to the parts beyond the ligature. And herein consists the difference between the tight and the medium ligature, that the former not only prevents the passage of the blood in the veins, but in the arteries also; the latter, however, whilst it does not prevent the force of the pulse from extending beyond it, and so propelling the blood to the extremities of the body, compresses the veins, and greatly or altogether impedes the return of the blood through them. Seeing, therefore, that the moderately tight ligature renders the veins turgid and distended, and the whole hand full of blood, I ask, whence is this? Does the blood accumulate below the ligature coming through the veins, or through the arteries, or passing by certain hidden porosities? Through the veins it cannot come; still less can it come through invisible channels; it must needs, then, arrive by the arteries, in conformity with all that has been already said. That it cannot flow in by the veins appears plainly enough from the fact that the blood cannot be forced towards the heart unless the ligature be removed; when this is done suddenly all the veins collapse, and disgorge themselves of their contents into the superior parts, the hand at the same time resumes its natural pale colour, the tumefaction and the stagnating blood having disappeared. Moreover, he whose arm or wrist has thus been bound for some little time with the medium bandage, so that it has not only got swollen and livid but cold, when the fillet is undone is aware of something cold making its way upwards along with the returning blood, and reaching the elbow or the axilla. And I have myself been inclined to think that this cold blood rising upwards to the heart was the cause of the fainting that often occurs after blood-letting: fainting frequently supervenes even in robust subjects, and mostly at the moment of undoing the fillet, as the vulgar say, from the turning of the blood. Farther, when we see the veins below the ligature instantly swell up and become gorged, when from extreme tightness it is somewhat relaxed, the arteries meantime continuing unaffected, this is an obvious indication that the blood passes from the arteries into the veins, and not from the veins into the arteries, and that there is either an anastomosis of the two orders of vessels, or porosities in the flesh and solid parts generally that are permeable to the blood It is farther an indication that the veins have frequent communications with one another, because they all become turgid together, whilst under the medium ligature applied above the elbow; and if any single small vein be pricked with a lancet, they all speedily shrink, and disburthening themselves into this they subside almost simultaneously. These considerations will enable anyone to understand the nature of the attraction that is exerted by ligatures, and perchance of fluxes generally; how, for example, when the veins are compressed by a bandage of medium tightness applied above the elbow, the blood cannot escape, whilst it still continues to be driven in, by the forcing power of the heart, by which the parts are of necessity filled, gorged with blood. And how should it be otherwise? Heat and pain and a vacuum draw, indeed; but in such wise only that parts are filled, not preternaturally distended or gorged, and not so suddenly and violently overwhelmed with the charge of blood forced in upon them, that the flesh is lacerated and the vessels ruptured. Nothing of the kind as an effect of heat, or pain, or the vacuum force, is either credible or demonstrable. Besides, the ligature is competent to occasion the afflux in question without either pain, or heat, or a vacuum. Were pain in any way the cause, how should it happen that, with the arm bound above the elbow, the hand and fingers should swell being the bandage, and their veins become distended? The pressure of the bandage certainly prevents the blood from getting there by the veins. And then, wherefore is there neither swelling nor repletion of the veins, nor any sign or symptom of attraction or afflux, above the ligature? But this is the obvious cause of the preternatural attraction and swelling below the bandage, and in the hand and fingers, that the blood is entering abundantly, and with force, but cannot pass out again. Now is not this the cause of all tumefaction, as indeed Avicenna has it, and of all oppressive redundancy in parts, that the access to them is open, but the egress from them is. closed? Whence it comes that they are gorged and tumefied. And may not the same thing happen in local inflammations, where, so long as the swelling is on the increase, and has not reached its extreme term, a full pulse is felt in the part, especially when the disease is of the more acute kind, and the swelling usually takes place most rapidly. But these are matters for after discussion. Or does this, which occurred in my own case, happen from the same cause? Thrown from a carriage upon one occasion, I struck my forehead a blow upon the place where a twig of the artery advances from the temple, and immediately, within the time in which twenty beats could have been made I felt a tumour the size of an egg developed, without either heat or any great pain: the near vicinity of the artery had caused the blood to be effused into the bruised part with unusual force and velocity. And now, too, we understand why in phlebotomy we apply our ligature above the part that is punctured, not below it; did the flow come from above, not from below, the constriction in this case would not only be of no service, but would prove a positive hindrance; it would have to be applied below the orifice, in order to have the flow more free, did the blood descend by the veins from superior to inferior parts; but as it is elsewhere forced through the extreme arteries into the extreme veins, and the return in these last is opposed by the ligature, so do they fill and swell, and being thus filled and distended, they are made capable of projecting their charge with force, and to a distance, when any one of them is suddenly punctured; but the ligature being slackened, and the returning channels thus left open, the blood forthwith no longer escapes, save by drops; and, as all the world knows, if in performing phlebotomy the bandage be either slackened too much or the limb be bound too tightly, the blood escapes without force, because in the one case the returning channels are not adequately obstructed; in other the channels of influx, the arteries, are impeded. CHAPTER XII THAT THERE IS A CIRCULATION OF THE BLOOD IS SHOWN FROM THE SECOND POSITION DEMONSTRATED If these things be so, another point which I have already referred to, viz., the continual passage of the blood through the heart will also be confirmed. We have seen, that the blood passes from the arteries into the veins, not from the veins into the arteries; we have seen, farther, that almost the whole of the blood may be withdrawn from a puncture made in one of the cutaneous veins of the arm if a bandage properly applied be used; we have seen, still farther, that the blood flows so freely and rapidly that not only is the whole quantity which was contained in the arm beyond the ligature, and before the puncture was made, discharged, but the whole which is contained in the body, both that of the arteries and that of the veins. Whence we must admit, first, that the blood is sent along with an impulse, and that it is urged with force below the ligature; for it escapes with force, which force it receives from the pulse and power of the heart; for the force and motion of the blood are derived from the heart alone. Second, that the afflux proceeds from the heart, and through the heart by a course from the great veins; for it gets into the parts below the ligature through the arteries, not through the veins; and the arteries nowhere receive blood from the veins, nowhere receive blood save and except from the left ventricle of the heart. Nor could so large a quantity of blood be drawn from one vein (a ligature having been duly applied), nor with such impetuousity, such readiness, such celerity, unless through the medium of the impelling power of the heart. But if all things be as they are now represented, we shall feel ourselves at liberty to calculate the quantity of the blood, and to reason on its circular motion. Should anyone, for instance, performing phlebotomy, suffer the blood to flow in the manner it usually does, with force and freely, for some half hour or so, no question but that the greatest part of the blood being abstracted, faintings and syncopes would ensue, and that not only would the arteries but the great veins also be nearly emptied of their contents. It is only consonant with reason to conclude that in the course of the half hour hinted at, so much as has escaped has also passed from the great veins through the heart into the aorta. And further, if we calculate how many ounces flow through one arm, or how many pass in twenty or thirty pulsations under the medium ligature, we shall have some grounds for estimating how much passes through the other arm in the same space of time: how much through both lower extremities, how much through the neck on either side, and through all the other arteries and veins of the body, all of which have been supplied with fresh blood, and as this blood must have passed through the lungs and ventricles of the heart, and must have come from the great veins, we shall perceive that a circulation is absolutely necessary, seeing that the quantities hinted at cannot be supplied immediately from the ingesta, and are vastly more than can be requisite for the mere nutrition of the parts. It is still further to be observed, that in practising phlebotomy the truths contended for are sometimes confirmed in another way; for having tied up the arm properly, and made the puncture duly, still, if from alarm or any other causes, a state of faintness supervenes, in which the heart always pulsates more languidly, the blood does not flow freely, but distils by drops only. The reason is, that with a somewhat greater than usual resistance offered to the transit of the blood by the bandage, coupled with the weaker action of the heart, and its diminished impelling power, the stream cannot make its way under the ligature; and farther, owing to the weak and languishing state of the heart, the blood is not transferred in such quantity as wont from the veins to the arteries through the sinuses of that organ. So also, and for the same reasons, are the menstrual fluxes of women, and indeed hemorrhages of every kind, controlled. And now, a contrary state of things occurring, the patient getting rid of his fear and recovering his courage, the pulse strength is increased, the arteries begin again to beat with greater force, and to drive the blood even into the part that is bound; so that the blood now springs from the puncture in the vein, and flows in continuous stream. CHAPTER XIII THE THIRD POSITION IS CONFIRMED: AND THE CIRCULATION OF THE BLOOD IS DEMONSTRATED FROM IT Thus far we have spoken of the quantity of blood passing through the heart and the lungs in the centre of the body, and in like manner from the arteries into the veins in the peripheral parts and the body at large. We have yet to explain, however, in what manner the blood finds its way back to the heart from the extremities by the veins, and how and in what way these are the only vessels that convey the blood from the external to the central parts; which done, I conceive that the three fundamental propositions laid down for the circulation of the blood will be so plain, so well established, so obviously true, that they may claim general credence. Now the remaining position will be made sufficiently clear from the valves which are found in the cavities of the veins themselves, from the uses of these, and from experiments cognisable by the senses. The celebrated Hieronymus Fabricius of Aquapendente, a most skilful anatomist, and venerable old man, or, as the learned Riolan will have it, Jacobus Silvius, first gave representations of the valves in the veins, which consist of raised or loose portions of the inner membranes of these vessels, of extreme delicacy, and a sigmoid or semilunar shape. They are situated at different distances from one another, and diversely in different individuals; they are connate at the sides of the veins; they are directed upwards towards the trunks of the veins; the two--for there are for the most part two together--regard each other, mutually touch, and are so ready to come into contact by their edges, that if anything attempts to pass from the trunks into the branches of the veins, or from the greater vessels into the less, they completely prevent it; they are farther so arranged, that the horns of those that succeed are opposite the middle of the convexity of those that and so on alternately. The discoverer of these valves did not rightly understand their use, nor have succeeding anatomists added anything to our knowledge: for their office is by no means explained when we are told that it is to hinder the blood, by its weight, from all flowing into inferior parts; for the edges of the valves in the jugular veins hang downwards, and are so contrived that they prevent the blood from rising upwards; the valves, in a word, do not invariably look upwards, but always toward the trunks of the veins, invariably towards the seat of the heart. I, and indeed others, have sometimes found valves in the emulgent veins, and in those of the mesentery, the edges of which were directed towards the vena cava and vena portae. Let it be added that there are no valves in the arteries, and that dogs, oxen, etc., have invariably valves at the divisions of their crural veins, in the veins that meet towards the top of the os sacrum, and in those branches which come from the haunches, in which no such effect of gravity from the erect position was to be apprehended. Neither are there valves in the jugular veins for the purpose of guarding against apoplexy, as some have said; because in sleep the head is more apt to be influenced by the contents of the carotid arteries. Neither are the valves present, in order that the blood may be retained in the divarications or smaller trunks and minuter branches, and not be suffered to flow entirely into the more open and capacious channels; for they occur where there are no divarications; although it must be owned that they are most frequent at the points where branches join. Neither do they exist for the purpose of rendering the current of blood more slow from the centre of the body; for it seems likely that the blood would be disposed to flow with sufficient slowness of its own accord, as it would have to pass from larger into continually smaller vessels, being separated from the mass and fountain head, and attaining from warmer into colder places. But the valves are solely made and instituted lest the blood should pass from the greater into the lesser veins, and either rupture them or cause them to become varicose; lest, instead of advancing from the extreme to the central parts of the body, the blood should rather proceed along the veins from the centre to the extremities; but the delicate valves, while they readily open in the right direction, entirely prevent all such contrary motion, being so situated and arranged, that if anything escapes, or is less perfectly obstructed by the cornua of the one above, the fluid passing, as it were, by the chinks between the cornua, it is immediately received on the convexity of the one beneath, which is placed transversely with reference to the former, and so is effectually hindered from getting any farther. And this I have frequently experienced in my dissections of the veins: if I attempted to pass a probe from the trunk of the veins into one of the smaller branches, whatever care I took I found it impossible to introduce it far any way, by reason of the valves; whilst, on the contrary, it was most easy to push it along in the opposite direction, from without inwards, or from the branches towards the trunks and roots. In many places two valves are so placed and fitted, that when raised they come exactly together in the middle of the vein, and are there united by the contact of their margins; and so accurate is the adaptation, that neither by the eye nor by any other means of examination, can the slightest chink along the line of contact be perceived. But if the probe be now introduced from the extreme towards the more central parts, the valves, like the floodgates of a river, give way, and are most readily pushed aside. The effect of this arrangement plainly is to prevent all motion of the blood from the heart and vena cava, whether it be upwards towards the head, or downwards towards the feet, or to either side towards the arms, not a drop can pass; all motion of the blood, beginning; in the larger and tending towards the smaller veins, is opposed and resisted by them; whilst the motion that proceeds from the lesser to end in the larger branches is favoured, or, at all events, a free and open passage is left for it. But that this truth may be made the more apparent, let an arm be tied up above the elbow as if for phlebotomy (A, A, fig. 1). At intervals in the course of the veins, especially in labouring people and those whose veins are large, certain knots or elevations (B, C, D, E, F) will be perceived, and this not only at the places where a branch is received (E, F), but also where none enters (C, D): these knots or risings are all formed by valves, which thus show themselves externally. And now if you press the blood from the space above one of the valves, from H to O, (fig. 2,) and keep the point of a finger upon the vein inferiorly, you will see no influx of blood from above; the portion of the vein between the point of the finger and the valve O will be obliterated; yet will the vessel continue sufficiently distended above the valve (O, G). The blood being thus pressed out and the vein emptied, if you now apply a finger of the other hand upon the distended part of the vein above the valve O, (fig. 3,) and press downwards, you will find that you cannot force the blood through or beyond the valve; but the greater effort you use, you will only see the portion of vein that is between the finger and the valve become more distended, that portion of the vein which is below the valve remaining all the while empty (H, O, fig. 3). It would therefore appear that the function of the valves in the veins is the same as that of the three sigmoid valves which we find at the commencement of the aorta and pulmonary artery, viz., to prevent all reflux of the blood that is passing over them. [NOTE.--Woodcuts of the veins of the arm to which these letters and figures refer appear here in the original.--C. N. B. C] Farther, the arm being bound as before, and the veins looking full and distended, if you press at one part in the course of a vein with the point of a finger (L, fig. 4), and then with another finger streak the blood upwards beyond the next valve (N), you will perceive that this portion of the vein continues empty (L, N), and that the blood cannot retrograde, precisely as we have already seen the case to be in fig. 2; but the finger first applied (H, fig. 2, L, fig. 4), being removed, immediately the vein is filled from below, and the arm becomes as it appears at D C, fig. 1. That the blood in the veins therefore proceeds from inferior or more remote parts, and towards the heart, moving in these vessels in this and not in the contrary direction, appears most obviously. And although in some places the valves, by not acting with such perfect accuracy, or where there is but a single valve, do not seem totally to prevent the passage of the blood from the centre, still the greater number of them plainly do so; and then, where things appear contrived more negligently, this is compensated either by the more frequent occurrence or more perfect action of the succeeding valves, or in some other way: the veins in short, as they are the free and open conduits of the blood returning TO the heart, so are they effectually prevented from serving as its channels of distribution FROM the heart. But this other circumstance has to be noted: The arm being bound, and the veins made turgid, and the valves prominent, as before, apply the thumb or finger over a vein in the situation of one of the valves in such a way as to compress it, and prevent any blood from passing upwards from the hand; then, with a finger of the other hand, streak the blood in the vein upwards till it has passed the next valve above (N, fig. 4), the vessel now remains empty; but the finger at L being removed for an instant, the vein is immediately filled from below; apply the finger again, and having in the same manner streaked the blood upwards, again remove the finger below, and again the vessel becomes distended as before; and this repeat, say a thousand times, in a short space of time. And now compute the quantity of blood which you have thus pressed up beyond the valve, and then multiplying the assumed quantity by one thousand, you will find that so much blood has passed through a certain portion of the vessel; and I do now believe that you will find yourself convinced of the circulation of the blood, and of its rapid motion. But if in this experiment you say that a violence is done to nature, I do not doubt but that, if you proceed in the same way, only taking as great a length of vein as possible, and merely remark with what rapidity the blood flows upwards, and fills the vessel from below, you will come to the same conclusion. CHAPTER XIV CONCLUSION OF THE DEMONSTRATION OF THE CIRCULATION And now I may be allowed to give in brief my view of the circulation of the blood, and to propose it for general adoption. Since all things, both argument and ocular demonstration, show that the blood passes through the lungs, and heart by the force of the ventricles, and is sent for distribution to all parts of the body, where it makes its way into the veins and porosities of the flesh, and then flows by the veins from the circumference on every side to the centre, from the lesser to the greater veins, and is by them finally discharged into the vena cava and right auricle of the heart, and this in such a quantity or in such a flux and reflux thither by the arteries, hither by the veins, as cannot possibly be supplied by the ingesta, and is much greater than can be required for mere purposes of nutrition; it is absolutely necessary to conclude that the blood in the animal body is impelled in a circle, and is in a state of ceaseless motion; that this is the act or function which the heart performs by means of its pulse; and that it is the sole and only end of the motion and contraction of the heart. CHAPTER XV THE CIRCULATION OF THE BLOOD IS FURTHER CONFIRMED BY PROBABLE REASONS It will not be foreign to the subject if I here show further, from certain familiar reasonings, that the circulation is matter both of convenience and necessity. In the first place, since death is a corruption which takes place through deficiency of heat, [Footnote: Aristoteles De Respirations, lib. ii et iii: De Part. Animal. et alibi.] and since all living things are warm, all dying things cold, there must be a particular seat and fountain, a kind of home and hearth, where the cherisher of nature, the original of the native fire, is stored and preserved; from which heat and life are dispensed to all parts as from a fountain head; from which sustenance may be derived; and upon which concoction and nutrition, and all vegetative energy may depend. Now, that the heart is this place, that the heart is the principle of life, and that all passes in the manner just mentioned, I trust no one will deny. The blood, therefore, required to have motion, and indeed such a motion that it should return again to the heart; for sent to the external parts of the body far from its fountain, as Aristotle says, and without motion it would become congealed. For we see motion generating and keeping up heat and spirits under ail circumstances, and rest allowing them to escape and be dissipated. The blood, therefore, becoming thick or congealed by the cold of the extreme and outward parts, and robbed of its spirits, just as it is in the dead, it was imperative that from its fount and origin, it should again receive heat and spirits, and all else requisite to its preservation--that, by returning, it should be renovated and restored. We frequently see how the extremities are chilled by the external cold, how the nose and cheeks and hands look blue, and how the blood, stagnating in them as in the pendent or lower parts of a corpse, becomes of a dusky hue; the limbs at the same time getting torpid, so that they can scarcely be moved, and seem almost to have lost their vitality. Now they can by no means be so effectually, and especially so speedily restored to heat and colour and life, as by a new efflux and contact of heat from its source. But how can parts attract in which the heat and life are almost extinct? Or how should they whose passages are filled with condensed and frigid blood, admit fresh aliment--renovated blood --unless they had first got rid of their old contents? Unless the heart were truly that fountain where life and heat are restored to the refrigerated fluid, and whence new blood, warm, imbued with spirits, being sent out by the arteries, that which has become cooled and effete is forced on, and all the particles recover their heat which was failing, and their vital stimulus wellnigh exhausted. Hence it is that if the heart be unaffected, life and health may be restored to almost all the other parts of the body; but if the heart be chilled, or smitten with any serious disease, it seems matter of necessity that the whole animal fabric should suffer and fall into decay. When the source is corrupted, there is nothing, as Aristotle says, [Footnote: De Part. Animal., iii.] which can be of service either to it or aught that depends on it. And hence, by the way, it may perchance be why grief, and love, and envy, and anxiety, and all affections of the mind of a similar kind are accompanied with emaciation and decay, or with disordered fluids and crudity, which engender all manner of diseases and consume the body of man. For every affection of the mind that is attended with either pain or pleasure, hope or fear, is the cause of an agitation whose influence extends to the heart, and there induces change from the natural constitution, in the temperature, the pulse and the rest, which impairing all nutrition in its source and abating the powers at large, it is no wonder that various forms of incurable disease in the extremities and in the trunk are the consequence, inasmuch as in such circumstances the whole body labours under the effects of vitiated nutrition and a want of native heat. Moreover, when we see that all animals live through food digested in their interior, it is imperative that the digestion and distribution be perfect, and, as a consequence, that there be a place and receptacle where the aliment is perfected and whence it is distributed to the several members. Now this place is the heart, for it is the only organ in the body which contains blood for the general use; all the others receive it merely for their peculiar or private advantage, just as the heart also has a supply for its own especial behoof in its coronary veins and arteries. But it is of the store which the heart contains in its auricles and ventricles that I here speak. Then the heart is the only organ which is so situated and constituted that it can distribute the blood in due proportion to the several parts of the body, the quantity sent to each being according to the dimensions of the artery which supplies it, the heart serving as a magazine or fountain ready to meet its demands. Further, a certain impulse or force, as well as an impeller or forcer, such as the heart, was required to effect this distribution and motion of the blood; both because the blood is disposed from slight causes, such as cold, alarm, horror, and the like, to collect in its source, to concentrate like parts to a whole, or the drops of water spilt upon a table to the mass of liquid; and because it is forced from the capillary veins into the smaller ramifications, and from these into the larger trunks by the motion of the extremities and the compression of the muscles generally. The blood is thus more disposed to move from the circumference to the centre than in the opposite direction, even were there no valves to oppose its motion; wherefore, that it may leave its source and enter more confined and colder channels, and flow against the direction to which it spontaneously inclines, the blood requires both force and impelling power. Now such is the heart and the heart alone, and that in the way and manner already explained. CHAPTER XVI THE CIRCULATION OF THE BLOOD IS FURTHER PROVED FROM CERTAIN CONSEQUENCES There are still certain problems, which, taken as consequences of this truth assumed as proven, are not without their use in exciting belief, as it were, a posteriore; and which, although they may seem to be involved in much doubt and obscurity, nevertheless readily admit of having reasons and causes assigned for them. Of such a nature are those that present themselves in connexion with contagions, poisoned wounds, the bites of serpents and rabid animals, lues venerea and the like. We sometimes see the whole system contaminated, though the part first infected remains sound; the lues venerea has occasionally made its attack with pains in the shoulders and head, and other symptoms, the genital organs being all the while unaffected; and then we know that the wound made by a rabid dog having healed, fever and a train of disastrous symptoms may nevertheless supervene. Whence it appears that the contagion impressed upon or deposited in a particular part, is by-and-by carried by the returning current of blood to the heart, and by that organ is sent to contaminate the whole body. In tertian fever, the morbific cause seeking the heart in the first instance, and hanging about the heart and lungs, renders the patient short-winded, disposed to sighing, and indisposed to exertion, because the vital principle is oppressed and the blood forced into the lungs and rendered thick. It does not pass through them, (as I have myself seen in opening the bodies of those who had died in the beginning of the attack,) when the pulse is always frequent, small, and occasionally irregular; but the heat increasing, the matter becoming attenuated, the passages forced, and the transit made, the whole body begins to rise in temperature, and the pulse becomes fuller and stronger. The febrile paroxysm is fully formed, whilst the preternatural heat kindled in the heart is thence diffused by the arteries through the whole body along with the morbific matter, which is in this way overcome and dissolved by nature. When we perceive, further, that medicines applied externally exert their influence on the body just as if they had been taken internally, the truth we are contending for is confirmed. Colocynth and aloes in this way move the belly, cantharides excites the urine, garlic applied to the soles of the feet assists expectoration, cordials strengthen, and an infinite number of examples of the same kind might be cited. Perhaps it will not, therefore, be found unreasonable, if we say that the veins, by means of their orifices, absorb some of the things that are applied externally and carry this inwards with the blood, not otherwise, it may be, than those of the mesentery imbibe the chyle from the intestines and carry it mixed with the blood to the liver. For the blood entering the mesentery by the coeliac artery, and the superior and inferior mesenteries, proceeds to the intestines, from which, along with the chyle that has been attracted into the veins, it returns by their numerous ramifications into the vena portae of the liver, and from this into the vena cava, and this in such wise that the blood in these veins has the same colour and consistency as in other veins, in opposition to what many believe to be the fact. Nor indeed can we imagine two contrary motions in any capillary system--the chyle upwards, the blood downwards. This could scarcely take place, and must be held as altogether improbable. But is not the thing rather arranged as it is by the consummate providence of nature? For were the chyle mingled with the blood, the crude with the digested, in equal proportions, the result would not be concoction, transmutation, and sanguification, but rather, and because they are severally active and passive, a mixture or combination, or medium compound of the two, precisely as happens when wine is mixed with water and syrup. But when a very minute quantity of chyle is mingled with a very large quantity of circulating blood, a quantity of chyle that bears no kind of proportion to the mass of blood, the effect is the same, as Aristotle says, as when a drop of water is added to a cask of wine, or the contrary; the mass does not then present itself as a mixture, but is still sensibly either wine or water. So in the mesenteric veins of an animal we do not find either chyme or chyle and blood, blended together or distinct, but only blood, the same in colour, consistency, and other sensible properties, as it appears in the veins generally. Still as there is a certain though small and inappreciable portion of chyle or incompletely digested matter mingled with the blood, nature has interposed the liver, in whose meandering channels it suffers delay and undergoes additional change, lest arriving prematurely and crude at the heart, it should oppress the vital principle. Hence in the embryo, there is almost no use for the liver, but the umbilical vein passes directly through, a foramen or an anastomosis existing from the vena portae. The blood returns from the intestines of the foetus, not through the liver, but into the umbilical vein mentioned, and flows at once into the heart, mingled with the natural blood which is returning from the placenta; whence also it is that in the development of the foetus the liver is one of the organs that is last formed. I have observed all the members, perfectly marked out in the human foetus, even the genital organs, whilst there was yet scarcely any trace of the liver. And indeed at the period when all the parts, like the heart itself in the beginning, are still white, and except in the veins there is no appearance of redness, you shall see nothing in the seat of the liver but a shapeless collection, as it were, of extravasated blood, which you might take for the effects of a contusion or ruptured vein. But in the incubated egg there are, as it were, two umbilical vessels, one from the albumen passing entire through the liver, and going straight to the heart; another from the yelk, ending in the vena portae; for it appears that the chick, in the first instance, is entirely formed and nourished by the white; but by the yelk after it has come to perfection and is excluded from the shell; for this part may still be found in the abdomen of the chick many days after its exclusion, and is a substitute for the milk to other animals. But these matters will be better spoken of in my observations on the formation of the foetus, where many propositions, the following among the number, will be discussed: Wherefore is this part formed or perfected first, that last, and of the several members, what part is the cause of another? And there are many points having special reference to the heart, such as wherefore does it first acquire consistency, and appear to possess life, motion, sense, before any other part of the body is perfected, as Aristotle says in his third book, "De partibus Animalium"? And so also of the blood, wherefore does it precede all the rest? And in what way does it possess the vital and animal principle, and show a tendency to motion, and to be impelled hither and thither, the end for which the heart appears to be made? In the same way, in considering the pulse, why should one kind of pulse indicate death, another recovery? And so of all the other kinds of pulse, what may be the cause and indication of each? Likewise we must consider the reason of crises and natural critical discharges; of nutrition, and especially the distribution of the nutriment; and of defluxions of every description. Finally, reflecting on every part of medicine, physiology, pathology, semeiotics and therapeutics, when I see how many questions can be answered, how many doubts resolved, how much obscurity illustrated by the truth we have declared, the light we have made to shine, I see a field of such vast extent in which I might proceed so far, and expatiate so widely, that this my tractate would not only swell out into a volume, which was beyond my purpose, but my whole life, perchance, would not suffice for its completion. In this place, therefore, and that indeed in a single chapter, I shall only endeavour to refer the various particulars that present themselves in the dissection of the heart and arteries to their several uses and causes; for so I shall meet with many things which receive light from the truth I have been contending for, and which, in their turn, render it more obvious. And indeed I would have it confirmed and illustrated by anatomical arguments above all others. There is but a single point which indeed would be more correctly placed among our observations on the use of the spleen, but which it will not be altogether impertinent to notice in this place incidentally. From the splenic branch which passes into the pancreas, and from the upper part, arise the posterior coronary, gastric, and gastroepiploic veins, all of which are distributed upon the stomach in numerous branches and twigs, just as the mesenteric vessels are upon the intestines. In a similar way, from the inferior part of the same splenic branch, and along the back of the colon and rectum proceed the hemorrhoidal veins. The blood returning by these veins, and bringing the cruder juices along with it, on the one hand from the stomach, where they are thin, watery, and not yet perfectly chylified; on the other thick and more earthy, as derived from the faeces, but all poured into this splenic branch, are duly tempered by the admixture of contraries; and nature mingling together these two kinds of juices, difficult of coction by reason of most opposite defects, and then diluting them with a large quantity of warm blood, (for we see that the quantity returned from the spleen must be very large when we contemplate the size of its arteries,) they are brought to the porta of the liver in a state of higher preparation. The defects of either extreme are supplied and compensated by this arrangement of the veins. CHAPTER XVII THE MOTION AND CIRCULATION OF THE BLOOD ARE CONFIRMED FROM THE PARTICULARS APPARENT IN THE STRUCTURE OF THE HEART, AND FROM THOSE THINGS WHICH DISSECTION UNFOLDS I do not find the heart as a distinct and separate part in all animals; some, indeed, such as the zoophytes, have no heart; this is because these animals are coldest, of one great bulk, of soft texture, or of a certain uniform sameness or simplicity of structure; among the number I may instance grubs and earth-worms, and those that are engendered of putrefaction and do not preserve their species. These have no heart, as not requiring any impeller of nourishment into the extreme parts; for they have bodies which are connate and homogeneous and without limbs; so that by the contraction and relaxation of the whole body they assume and expel, move and remove, the aliment. Oysters, mussels, sponges, and the whole genus of zoophytes or plant-animals have no heart, for the whole body is used as a heart, or the whole animal is a heart. In a great number of animals,--almost the whole tribe of insects--we cannot see distinctly by reason of the smallness of the body; still in bees, flies, hornets, and the like we can perceive something pulsating with the help of a magnifying-glass; in pediculi, also, the same thing may be seen, and as the body is transparent, the passage of the food through the intestines, like a black spot or stain, may be perceived by the aid of the same magnifying-glass. But in some of the pale-blooded and colder animals, as in snails, whelks, shrimps, and shell-fish, there is a part which pulsates, --a kind of vesicle or auricle without a heart,--slowly, indeed, and not to be perceived except in the warmer season of the year. In these creatures this part is so contrived that it shall pulsate, as there is here a necessity for some impulse to distribute the nutritive fluid, by reason of the variety of organic parts, or of the density of the substance; but the pulsations occur unfrequently, and sometimes in consequence of the cold not at all, an arrangement the best adapted to them as being of a doubtful nature, so that sometimes they appear to live, sometimes to die; sometimes they show the vitality of an animal, sometimes of a vegetable. This seems also to be the case with the insects which conceal themselves in winter, and lie, as it were, defunct, or merely manifesting a kind of vegetative existence. But whether the same thing happens in the case of certain animals that have red blood, such as frogs, tortoises, serpents, swallows, may be very properly doubted. In all the larger and warmer animals which have red blood, there was need of an impeller of the nutritive fluid, and that, perchance, possessing a considerable amount of power. In fishes, serpents, lizards, tortoises, frogs, and others of the same kind there is a heart present, furnished with both an auricle and a ventricle, whence it is perfectly true, as Aristotle has observed, [Footnote: De Part. Animal., lib. iii.] that no sanguineous animal is without a heart, by the impelling power of which the nutritive fluid is forced, both with greater vigour and rapidity, to a greater distance; and not merely agitated by an auricle, as it Is in lower forms. And then in regard to animals that are yet larger, warmer, and more perfect, as they abound in blood, which is always hotter and more spirituous, and which possess bodies of greater size and consistency, these require a larger, stronger, and more fleshy heart, in order that the nutritive fluid may be propelled with yet greater force and celerity. And further, inasmuch as the more perfect animals require a still more perfect nutrition, and a larger supply of native heat, in order that the aliment may be thoroughly concocted and acquire the last degree of perfection, they required both lungs and a second ventricle, which should force the nutritive fluid through them. Every animal that has lungs has, therefore, two ventricles to its heart--one right, the other left; and wherever there is a right, there also is there a left ventricle; but the contrary of this does not hold good: where there is a left there is not always a right ventricle. The left ventricle I call that which is distinct in office, not in place from the other, that one, namely, which distributes the blood to the body at large, not to the lungs only. Hence the left ventricle seems to form the principle part of the heart; situated in the middle, more strongly marked, and constructed with greater care, the heart seems formed for the sake of the left ventricle, and the right but to minister to it. The right neither reaches to the apex of the heart nor is it nearly of such strength, being three times thinner in its walls, and in some sort jointed on to the left (as Aristotle says), though, indeed, it is of greater capacity, inasmuch as it has not only to supply material to the left ventricle, but likewise to furnish aliment to the lungs. It is to be observed, however, that all this is otherwise in the embryo, where there is not such a difference between the two ventricles. There, as in a double nut, they are nearly equal in all respects, the apex of the right reaching to the apex of the left, so that the heart presents itself as a sort of double- pointed cone. And this is so, because in the foetus, as already said, whilst the blood is not passing through the lungs from the right to the left cavities of the heart, it flows by the foramen ovale and ductus arteriosus directly from the vena cava into the aorta, whence it is distributed to the whole body. Both ventricles have, therefore, the same office to perform, whence their equality of constitution. It is only when the lungs come to be used and it is requisite that the passages indicated should be blocked up that the difference in point of strength and other things between the two ventricles begins to be apparent. In the altered circumstances the right has only to drive the blood through the lungs, whilst the left has to propel it through the whole body. There are, moreover, within the heart numerous braces, in the form of fleshy columns and fibrous bands, which Aristotle, in his third book on "Respiration," and the "Parts of Animals," entitles nerves. These are variously extended, and are either distinct or contained in grooves in the walls and partition, where they occasion numerous pits or depressions. They constitute a kind of small muscles, which are superadded and supplementary to the heart, assisting it to execute a more powerful and perfect contraction, and so proving subservient to the complete expulsion of the blood. They are, in some sort, like the elaborate and artful arrangement of ropes in a ship, bracing the heart on every side as it contracts, and so enabling it more effectually and forcibly to expel the charge of blood from its ventricles. This much is plain, at all events, that in some animals they are less strongly marked than in others; and, in all that have them, they are more numerous and stronger in the left than in the right ventricle; and while some have them present in the left, yet they are absent in the right ventricle. In man they are more numerous in the left than in the right ventricle, more abundant in the ventricles than in the auricles; and occasionally there appear to be none present in the auricles. They are numerous in the large, more muscular and hardier bodies of countrymen, but fewer in more slender frames and in females. In those animals in which the ventricles of the heart are smooth within and entirely without fibres of muscular bands, or anything like hollow pits, as in almost all the smaller birds, the partridge and the common fowl, serpents, frogs, tortoises, and most fishes, there are no chordae tendineae, nor bundles of fibres, neither are there any tricuspid valves in the ventricles. Some animals have the right ventricle smooth internally, but the left provided with fibrous bands, such as the goose, swan, and larger birds; and the reason is the same here as elsewhere. As the lungs are spongy and loose and soft, no great amount of force is required to force the blood through them; therefore the right ventricle is either without the bundles in question, or they are fewer and weaker, and not so fleshy or like muscles. Those of the left ventricle, however, are both stronger and more numerous, more fleshy and muscular, because the left ventricle requires to be stronger, inasmuch as the blood which it propels has to be driven through the whole body. And this, too, is the reason why the left ventricle occupies the middle of the heart, and has parietes three times thicker and stronger than those of the right Hence all animals--and among men it is similar--that are endowed with particularly strong frames, and with large and fleshy limbs at a great distance from the heart, have this central organ of greater thickness, strength, and muscularity. This is manifest and necessary. Those, on the contrary, that are of softer and more slender make have the heart more flaccid, softer, and internally either less or not at all fibrous. Consider, farther, the use of the several valves, which are all so arranged that the blood, once received into the ventricles of the heart, shall never regurgitate; once forced into the pulmonary artery and aorta, shall not flow back upon the ventricles. When the valves are raised and brought together, they form a three-cornered line, such as is left by the bite of a leech; and the more they are forced, the more firmly do they oppose the passage of the blood. The tricuspid valves are placed, like gate-keepers, at the entrance into the ventricles from the venae cavae and pulmonary veins, lest the blood when most forcibly impelled should flow back. It is for this reason that they are not found in all animals, nor do they appear to have been constructed with equal care, in all animals in which they are found. In some they are more accurately fitted, in others more remissly or carelessly contrived, and always with a view to their being closed under a greater or a slighter force of the ventricle. In the left ventricle, therefore, in order that the occlusion may be the more perfect against the greater impulse, there are only two valves, like a mitre, and produced into an elongated cone, so that they come together and touch to their middle; a circumstance which perhaps led Aristotle into the error of supposing this ventricle to be double, the division taking place transversely. For the same reason, and that the blood may not regurgitate upon the pulmonary veins, and thus the force of the ventricle in propelling the blood through the system at large come to be neutralized, it is that these mitral valves excel those of the right ventricle in size and strength and exactness of closing. Hence it is essential that there can be no heart without a ventricle, since this must be the source and store-house of the blood. The same law does not hold good in reference to the brain. For almost no genus of birds has a ventricle in the brain, as is obvious in the goose and swan, the brains of which nearly equal that of a rabbit in size; now rabbits have ventricles in the brain, whilst the goose has none. In like manner, wherever the heart has a single ventricle, there is an auricle appended, flaccid, membranous, hollow, filled with blood; and where there are two ventricles, there are likewise two auricles. On the other hand, some animals have an auricle without any ventricle; or, at all events, they have a sac analogous to an auricle; or the vein itself, dilated at a particular part, performs pulsations, as is seen in hornets, bees, and other insects, which certain experiments of my own enable me to demonstrate, have not only a pulse, but a respiration in that part which is called the tail, whence it is that this part is elongated and contracted now more rarely, now more frequently, as the creature appears to be blown and to require a large quantity of air. But of these things, more in our "Treatise On Respiration." It is in like manner evident that the auricles pulsate, contract, as I have said before, and throw the blood into the ventricles; so that wherever there is a ventricle, an auricle is necessary, not merely that it may serve, according to the general belief, as a source and magazine for the blood: for what were the use of its pulsations had it only to contain? The auricles are prime movers of the blood, especially the right auricle, which, as already said, is "the first to live, the last to die"; whence they are subservient to sending the blood into the ventricles, which, contracting continuously, more readily and forcibly expel the blood already in motion; just as the ball- player can strike the ball more forcibly and further if he takes it on the rebound than if he simply threw it. Moreover, and contrary to the general opinion, neither the heart nor anything else can dilate or distend itself so as to draw anything into its cavity during the diastole, unless, like a sponge, it has been first compressed and is returning to its primary condition. But in animals all local motion proceeds from, and has its origin in, the contraction of some part; consequently it is by the contraction of the auricles that the blood is thrown into the ventricles, as I have already shown, and from there, by the contraction of the ventricles, it is propelled and distributed. Concerning local motions, it is true that the immediate moving organ in every motion of an animal primarily endowed with a motive spirit (as Aristotle has it [Footnote: In the book de Spiritu, and elsewhere.]) is contractile; in which way the word veopou is derived from veuw, nuto, contraho; and if I am permitted to proceed in my purpose of making a particular demonstration of the organs of motion in animals from observations in my possession, I trust I shall be able to make sufficiently plain how Aristotle was acquainted with the muscles, and advisedly referred all motion in animals to the nerves, or to the contractile element, and, therefore, called those little bands in the heart nerves. But that we may proceed with the subject which we have in hand, viz., the use of the auricles in filling the ventricles, we should expect that the more dense and compact the heart, the thicker its parietes, the stronger and more muscular must be the auricle to force and fill it, and vice versa. Now this is actually so: in some the auricle presents itself as a sanguinolent vesicle, as a thin membrane containing blood, as in fishes, in which the sac that stands in lieu of the auricles is of such delicacy and ample capacity that it seems to be suspended or to float above the heart. In those fishes in which the sac is somewhat more fleshy, as in the carp, barbel, tench, and others, it bears a wonderful and strong resemblance to the lungs. In some men of sturdier frame and stouter make the right auricle is so strong, and so curiously constructed on its inner surface of bands and variously interlacing fibres, that it seems to equal in strength the ventricle of the heart in other subjects; and I must say that I am astonished to find such diversity in this particular in different individuals. It is to be observed, however, that in the foetus the auricles are out of all proportion large, which is because they are present before the heart makes its appearance or suffices for its office even when it has appeared, and they, therefore, have, as it were, the duty of the whole heart committed to them, as has already been demonstrated. But what I have observed in the formation of the foetus, as before remarked (and Aristotle had already confirmed all in studying the incubated egg), throws the greatest light and likelihood upon the point. Whilst the foetus is yet in the form of a soft worm, or, as is commonly said, in the milk, there is a mere bloody point or pulsating vesicle, a portion apparently of the umbilical vein, dilated at its commencement or base. Afterwards, when the outline of the foetus is distinctly indicated and it begins to have greater bodily consistence, the vesicle in question becomes more fleshy and stronger, changes its position, and passes into the auricles, above which the body of the heart begins to sprout, though as yet it apparently performs no office. When the foetus is farther advanced, when the bones can be distinguished from the fleshy parts and movements take place, then it also has a heart which pulsates, and, as I have said, throws blood by either ventricle from the vena cava into the arteries. Thus nature, ever perfect and divine, doing nothing in vain, has neither given a heart where it was not required, nor produced it before its office had become necessary; but by the same stages in the development of every animal, passing through the forms of all, as I may say (ovum, worm, foetus), it acquires perfection in each. These points will be found elsewhere confirmed by numerous observations on the formation of the foetus. Finally, it is not without good grounds that Hippocrates in his book, "De Corde," entitles it a muscle; its action is the same; so is its functions, viz., to contract and move something else-- in this case the charge of the blood. Farther, we can infer the action and use of the heart from the arrangement of its fibres and its general structures, as in muscles generally. All anatomists admit with Galen that the body of the heart is made up of various courses of fibres running straight, obliquely, and transversely, with reference to one another; but in a heart which has been boiled, the arrangement of the fibres is seen to be different. All the fibres in the parietes and septum are circular, as in the sphincters; those, again, which are in the columns extend lengthwise, and are oblique longitudinally; and so it comes to pass that when all the fibres contract simultaneously, the apex of the cone is pulled towards its base by the columns, the walls are drawn circularly together into a globe--the whole heart, in short, is contracted and the ventricles narrowed. It is, therefore, impossible not to perceive that, as the action of the organ is so plainly contraction, its function is to propel the blood into the arteries. Nor are we the less to agree with Aristotle in regard to the importance of the heart, or to question if it receives sense and motion from the brain, blood from the liver, or whether it be the origin of the veins and of the blood, and such like. They who affirm these propositions overlook, or do not rightly understand, the principal argument, to the effect that the heart is the first part which exists, and that it contains within itself blood, life, sensation, and motion, before either the brain or the liver were created or had appeared distinctly, or, at all events, before they could perform any function. The heart, ready furnished with its proper organs of motion, like a kind of internal creature, existed before the body. The first to be formed, nature willed that it should afterwards fashion, nourish, preserve, complete the entire animal, as its work and dwelling- place: and as the prince in a kingdom, in whose hands lie the chief and highest authority, rules over all, the heart is the source and foundation from which all power is derived, on which all power depends in the animal body. Many things having reference to the arteries farther illustrate and confirm this truth. Why does not the pulmonary vein pulsate, seeing that it is numbered among the arteries? Or wherefore is there a pulse in the pulmonary artery? Because the pulse of the arteries is derived from the impulse of the blood. Why does an artery differ so much from a vein in the thickness and strength of its coats? Because it sustains the shock of the impelling heart and streaming blood. Hence, as perfect nature does nothing in vain, and suffices under all circumstances, we find that the nearer the arteries are to the heart, the more do they differ from the veins in structure; here they are both stronger and more ligamentous, whilst in extreme parts of the body, such as the feet and hands, the brain, the mesentery, and the testicles, the two orders of vessels are so much alike that it is impossible to distinguish between them with the eye. Now this is for the following very sufficient reasons: the more remote the vessels are from the heart, with so much the less force are they distended by the stroke of the heart, which is broken by the great distance at which it is given. Add to this that the impulse of the heart exerted upon the mass of blood, which must needs fill the trunks and branches of the arteries, is diverted, divided, as it were, and diminished at every subdivision, so that the ultimate capillary divisions of the arteries look like veins, and this not merely in constitution, but in function. They have either no perceptible pulse, or they rarely exhibit one, and never except where the heart beats more violently than usual, or at a part where the minute vessel is more dilated or open than elsewhere. It, therefore, happens that at times we are aware of a pulse in the teeth, in inflammatory tumours, and in the fingers; at another time we feel nothing of the sort. By this single symptom I have ascertained for certain that young persons whose pulses are naturally rapid were labouring under fever; and in like manner, on compressing the fingers in youthful and delicate subjects during a febrile paroxysm, I have readily perceived the pulse there. On the other hand, when the heart pulsates more languidly, it is often impossible to feel the pulse not merely in the fingers, but the wrist, and even at the temple, as in persons afflicted with lipothymiae asphyxia, or hysterical symptoms, and in the debilitated and moribund. Here surgeons are to be advised that, when the blood escapes with force in the amputation of limbs, in the removal of tumours, and in wounds, it constantly comes from an artery; not always indeed per saltum, because the smaller arteries do not pulsate, especially if a tourniquet has been applied. For the same reason the pulmonary artery not only has the structure of an artery, but it does not differ so widely from the veins in the thickness of its walls as does the aorta. The aorta sustains a more powerful shock from the left than the pulmonary artery does from the right ventricle, and the walls of this last vessel are thinner and softer than those of the aorta in the same proportion as the walls of the right ventricle of the heart are weaker and thinner than those of the left ventricle. In like manner the lungs are softer and laxer in structure than the flesh and other constituents of the body, and in a similar way the walls of the branches of the pulmonary artery differ from those of the vessels derived from the aorta. And the same proportion in these particulars is universally preserved. The more muscular and powerful men are, the firmer their flesh; the stronger, thicker, denser, and more fibrous their hearts, the thicker, closer, and stronger are the auricles and arteries. Again, in those animals the ventricles of whose hearts are smooth on their inner surface, without villi or valves, and the walls of which are thin, as in fishes, serpents, birds, and very many genera of animals, the arteries differ little or nothing in the thickness of their coats from the veins. Moreover, the reason why the lungs have such ample vessels, both arteries and veins (for the capacity of the pulmonary veins exceeds that of both crural and jugular vessels), and why they contain so large a quantity of blood, as by experience and ocular inspection we know they do, admonished of the fact indeed by Aristotle, and not led into error by the appearances found in animals which have been bled to death, is, because the blood has its fountain, and storehouse, and the workshop of its last perfection, in the heart and lungs. Why, in the same way, we find in the course of our anatomical dissections the pulmonary vein and left ventricle so full of blood, of the same black colour and clotted character as that with which the right ventricle and pulmonary artery are filled, is because the blood is incessantly passing from one side of the heart to the other through the lungs. Wherefore, in fine, the pulmonary artery has the structure of an artery, and the pulmonary veins have the structure of veins. In function and constitution and everything else the first is an artery, the others are veins, contrary to what is commonly believed; and the reason why the pulmonary artery has so large an orifice is because it transports much more blood than is requisite for the nutrition of the lungs. All these appearances, and many others, to be noted in the course of dissection, if rightly weighed, seem clearly to illustrate and fully to confirm the truth contended for throughout these pages, and at the same time to oppose the vulgar opinion; for it would be very difficult to explain in any other way to what purpose all is constructed and arranged as we have seen it to be. THE THREE ORIGINAL PUBLICATIONS ON VACCINATION AGAINST SMALLPOX BY EDWARD JENNER INTRODUCTORY NOTE Edward Jenner was born at his father's vicarage at Berkeley, Gloucestershire, England, on May 17, 1749. After leaving school, he was apprenticed to a local surgeon, and in 1770 he went to London and became a resident pupil under the great surgeon and anatomist, John Hunter, with whom he remained on intimate terms for the rest of Hunter's life. In 1773 he took up practise at Berkeley, where, except for numerous visits to London, he spent the rest of his life. He died of apoplexy on January 26, 1823. Jenner's scientific interests were varied, but the importance of his work in vaccination has overshadowed his other results. Early in his career he had begun to observe the phenomena of cowpox, a disease common in the rural parts of the western counties of England, and he was familiar with the belief, current among the peasantry, that a person who had suffered from the cowpox could not take smallpox. Finally, in 1796, he made his first experiment in vaccination, inoculating a boy of eight with cowpox, and, after his recovery, with smallpox; with the result that the boy did not take the latter disease. Jenner's first paper on his discovery was never printed; but in 1798 appeared the first of the following treatises. Its reception by the medical profession was highly discouraging; but progress began when Cline, the surgeon of St. Thomas's Hospital, used the treatment with success. Jenner continued his investigations, publishing his results from time to time, and gradually gaining recognition; though opposition to his theory and practise was at first vehement, and has never entirely disappeared. In 1802, Parliament voted him 10,000 pounds, and in 1806, 20,000 pounds, in recognition of the value of his services, and the sacrifices they had entailed. As early as 1807, Bavaria made vaccination compulsory; and since that date most of the European governments have officially encouraged or compelled the practise; and smallpox has ceased to be the almost universal scourge it was before Jenner's discovery. To C.H. PARRY, M.D. AT BATH MY DEAR FRIEND: In the present age of scientific investigation it is remarkable that a disease of so peculiar a nature as the cow-pox, which has appeared in this and some of the neighbouring counties for such a series of years, should so long have escaped particular attention. Finding the prevailing notions on the subject, both among men of our profession and others, extremely vague and indeterminate, and conceiving that facts might appear at once both curious and useful, I have instituted as strict an inquiry into the causes and effects of this singular malady as local circumstances would admit. The following pages are the result, which, from motives of the most affectionate regard, are dedicated to you, by Your sincere friend, EDWARD JENNER. BERKELEY, GLOUCESTERSHIRE, June 21st, 1798. VACCINATION AGAINST SMALLPOX I AN INQUIRY INTO THE CAUSES AND EFFECTS OF THE VARIOLE VACCINE, OR COW-POX. 1798 The deviation of man from the stage in which he was originally placed by nature seems to have proved to him a prolific source of diseases. From the love of splendour, from the indulgences of luxury, and from his fondness for amusement he has familiarised himself with a great number of animals, which may not originally have been intended for his associates. The wolf, disarmed of ferocity, is now pillowed in the lady's lap. [Footnote: The late Mr. John Hunter proved, by experiments, that the dog is the wolf in a degenerate state.] The cat, the little tiger of our island, whose natural home is the forest, is equally domesticated and caressed. The cow, the hog, the sheep, and the horse, are all, for a variety of purposes, brought under his care and dominion. There is a disease to which the horse, from his state of domestication, is frequently subject. The farriers have called it the grease. It is an inflammation and swelling in the heel, from which issues matter possessing properties of a very peculiar kind, which seems capable of generating a disease in the human body (after it has undergone the modification which I shall presently speak of), which bears so strong a resemblance to the smallpox that I think it highly probable it may be the source of the disease. In this dairy country a great number of cows are kept, and the office of milking is performed indiscriminately by men and maid servants. One of the former having been appointed to apply dressings to the heels of a horse affected with the grease, and not paying due attention to cleanliness, incautiously bears his part in milking the cows, with some particles of the infectious matter adhering to his fingers. When this is the case, it commonly happens that a disease is communicated to the cows, and from the cows to the dairymaids, which spreads through the farm until the most of the cattle and domestics feel its unpleasant consequences. This disease has obtained the name of the cow-pox. It appears on the nipples of the cows in the form of irregular pustules. At their first appearance they are commonly of a palish blue, or rather of a colour somewhat approaching to livid, and are surrounded by an erysipelatous inflammation. These pustules, unless a timely remedy be applied, frequently degenerate into phagedenic ulcers, which prove extremely troublesome. [Footnote: They who attend sick cattle in this country find a speedy remedy for stopping the progress of this complaint in those applications which act chemically upon the morbid matter, such as the solutions of the vitriolum zinci and the vitriolum cupri, etc.] The animals become indisposed, and the secretion of milk is much lessened. Inflamed spots now begin to appear on different parts of the hands of the domestics employed in milking, and sometimes on the wrists, which quickly run on to suppuration, first assuming the appearance of the small vesications produced by a burn. Most commonly they appear about the joints of the fingers and at their extremities; but whatever parts are affected, if the situation will admit, these superficial suppurations put on a circular form, with their edges more elevated than their centre, and of a colour distantly approaching to blue. Absorption takes place, and tumours appear in each axilla. The system becomes affected--the pulse is quickened; and shiverings, succeeded by heat, with general lassitude and pains about the loins and limbs, with vomiting, come on. The head is painful, and the patient is now and then even affected with delirium. These symptoms, varying in their degrees of violence, generally continue from one day to three or four, leaving ulcerated sores about the hands, which, from the sensibility of the parts, are very troublesome, and commonly heal slowly, frequently becoming phagedenic, like those from whence they sprung. The lips, nostrils, eyelids, and other parts of the body are sometimes affected with sores; but these evidently arise from their being heedlessly rubbed or scratched with the patient's infected fingers. No eruptions on the skin have followed the decline of the feverish symptoms in any instance that has come under my inspection, one only excepted, and in this case a very few appeared on the arms: they were very minute, of a vivid red colour, and soon died away without advancing to maturation; so that I cannot determine whether they had any connection with the preceding symptoms. Thus the disease makes its progress from the horse [Footnote: Jenner's conclusion that "grease" and cow-pox were the same disease has since been proved erroneous; but this error has not invalidated his main conclusion as to the relation of cow-pox and smallpox.--EDITOR.] to the nipple of the cow, and from the cow to the human subject Morbid matter of various kinds, when absorbed into the system, may produce effects in some degree similar; but what renders the cow-pox virus so extremely singular is that the person who has been thus affected is forever after secure from the infection of the smallpox; neither exposure to the variolous effluvia, nor the insertion of the matter into the skin, producing this distemper. In support of so extraordinary a fact, I shall lay before my reader a great number of instances. [Footnote: It is necessary to observe that pustulous sores frequently appear spontaneously on the nipples of cows, and instances have occurred, though very rarely, of the hands of the servants employed in milking being affected with sores in consequence, and even of their feeling an indisposition from absorption. These pustules arc of a much milder nature than those which arise from that contagion which constitutes the true cow-pox. They are always free from the bluish or livid tint so conspicuous in the pustules in that disease. No erysipelas attends them, nor do they shew any phagedenic disposition as in the other case, but quickly terminate in a scab without creating any apparent disorder in the cow. This complaint appears at various seasons of the year, but most commonly in the spring, when the cows are first taken from their winter food and fed with grass. It is very apt to appear also when they are suckling their young. But this disease is not to be considered as similar in any respect to that of which I am treating, as it is incapable of producing any specific effects on the human constitution. However, it is of the greatest consequence to point it out here, lest the want of discrimination should occasion an idea of security from the infection of the smallpox, which might prove delusive.] CASE I.--Joseph Merret, now an under gardener to the Earl of Berkeley, lived as a servant with a farmer near this place in the year 1770, and occasionally assisted in milking his master's cows. Several horses belonging to the farm began to have sore heels, which Merret frequently attended. The cows soon became affected with the cow-pox, and soon after several sores appeared on his hands. Swellings and stiffness in each axilla followed, and he was so much indisposed for several days as to be incapable of pursuing his ordinary employment. Previously to the appearance of the distemper among the cows there was no fresh cow brought into the farm, nor any servant employed who was affected with the cow-pox. In April, 1795, a general inoculation taking place here, Merret was inoculated with his family; so that a period of twenty-five years had elapsed from his having the cow-pox to this time. However, though the variolous matter was repeatedly inserted into his arm, I found it impracticable to infect him with it; an efflorescence only, taking on an erysipelatous look about the centre, appearing on the skin near the punctured parts. During the whole time that his family had the smallpox, one of whom had it very full, he remained in the house with them, but received no injury from exposure to the contagion. It is necessary to observe that the utmost care was taken to ascertain, with the most scrupulous precision, that no one whose case is here adduced had gone through the smallpox previous to these attempts to produce that disease. Had these experiments been conducted in a large city, or in a populous neighbourhood, some doubts might have been entertained; but here, where population is thin, and where such an event as a person's having had the smallpox is always faithfully recorded, as risk of inaccuracy in this particular can arise. CASE II.--Sarah Portlock, of this place, was infected with the cow-pox when a servant at a farmer's in the neighbourhood, twenty-seven years ago. [Footnote: I have purposely selected several cases in which the disease had appeared at a very distant period previous to the experiments made with variolous matter, to shew that the change produced in the constitution is not affected by time.] In the year 1792, conceiving herself, from this circumstance, secure from the infection of the smallpox, she nursed one of her own children who had accidentally caught the disease, but no indisposition ensued. During the time she remained in the infected room, variolous matter was inserted into both her arms, but without any further effect than in the preceding case. CASE III.--John Phillips, a tradesman of this town, had the cow- pox at so early a period as nine years of age. At the age of sixty-two I inoculated him, and was very careful in selecting matter in its most active state. It was taken from the arm of a boy just before the commencement of the eruptive fever, and instantly inserted. It very speedily produced a sting-like feel in the part. An efflorescence appeared, which on the fourth day was rather extensive, and some degree of pain and stiffness were felt about the shoulder; but on the fifth day these symptoms began to disappear, and in a day or two after went entirely off, without producing any effect on the system. CASE IV.--Mary Barge, of Woodford, in this parish, was inoculated with variolous matter in the year 1791. An efflorescence of a palish red colour soon appeared about the parts where the matter was inserted, and spread itself rather extensively, but died away in a few days without producing any variolous symptoms. [Footnote: It is remarkable that variolous matter, when the system is disposed to reject it, should excite inflammation on the part to which it is applied more speedily than when it produces the smallpox. Indeed, it becomes almost a criterion by which we can determine whether the infection will be received or not. It seems as if a change, which endures through life, had been produced in the action, or disposition to action, in the vessels of the skin; and it is remarkable, too, that whether this change has been effected by the smallpox or the cow-pox that the disposition to sudden cuticular inflammation is the same on the application of variolous matter.] She has since been repeatedly employed as a nurse to smallpox patients, without experiencing any ill consequences. This woman had the cow-pox when she lived in the service of a farmer in this parish thirty-one years before. CASE V.--Mrs. H---, a respectable gentlewoman of this town, had the cow-pox when very young. She received the infection in rather an uncommon manner: it was given by means of her handling some of the same utensils [Footnote: When the cow-pox has prevailed in the dairy, it has often been communicated to those who have not milked the cows, by the handle of the milk pail.] which were in use among the servants of the family, who had the disease from milking infected cows. Her hands had many of the cow-pox sores upon them, and they were communicated to her nose, which became inflamed and very much swollen. Soon after this event Mrs. H---- was exposed to the contagion of the smallpox, where it was scarcely possible for her to have escaped, had she been susceptible of it, as she regularly attended a relative who had the disease in so violent a degree that it proved fatal to him. In the year 1778 the smallpox prevailed very much at Berkeley, and Mrs. H----, not feeling perfectly satisfied respecting her safety (no indisposition having followed her exposure to the smallpox), I inoculated her with active variolous matter. The same appearance followed as in the preceding cases--an efflorescence on the arm without any effect on the constitution. CASE VI.--It is a fact so well known among our dairy farmers that those who have had the smallpox either escape the cow-pox or are disposed to have it slightly, that as soon as the complaint shews itself among the cattle, assistants are procured, if possible, who are thus rendered less susceptible of it, otherwise the business of the farm could scarcely go forward. In the month of May, 1796, the cow-pox broke out at Mr. Baker's, a farmer who lives near this place. The disease was communicated by means of a cow which was purchased in an infected state at a neighbouring fair, and not one of the farmer's cows (consisting of thirty) which were at that time milked escaped the contagion. The family consisted of a man servant, two dairymaids, and a servant boy, who, with the farmer himself, were twice a day employed in milking the cattle. The whole of this family, except Sarah Wynne, one of the dairymaids, had gone through the smallpox. The consequence was that the farmer and the servant boy escaped the infection of the cow-pox entirely, and the servant man and one of the maid servants had each of them nothing more then a sore on one of their fingers, which produced no disorder in the system. But the other dairymaid, Sarah Wynne, who never had the smallpox, did not escape in so easy a manner. She caught the complaint from the cows, and was affected with the symptoms described on page 154 in so violent a degree that she was confined to her bed, and rendered incapable for several days of pursuing her ordinary vocations in the farm. March 28, 1797, I inoculated this girl and carefully rubbed the variolous matter into two slight incisions made upon the left arm. A little inflammation appeared in the usual manner around the parts where the matter was inserted, but so early as the fifth day it vanished entirely without producing any effect on the system. CASE VII.--Although the preceding history pretty clearly evinces that the constitution is far less susceptible of the contagion of the cow-pox after it has felt that of the smallpox, and although in general, as I have observed, they who have had the smallpox, and are employed in milking cows which are infected with the cow- pox, either escape the disorder, or have sores on the hands without feeling any general indisposition, yet the animal economy is subject to some variation in this respect, which the following relation will point out: In the summer of the year 1796 the cow-pox appeared at the farm of Mr. Andrews, a considerable dairy adjoining to the town of Berkeley. It was communicated, as in the preceding instance, by an infected cow purchased at a fair in the neighbourhood. The family consisted of the farmer, his wife, two sons, a man and a maid servant; all of whom, except the farmer (who was fearful of the consequences), bore a part in milking the cows. The whole of them, exclusive of the man servant, had regularly gone through the smallpox; but in this case no one who milked the cows escaped the contagion. All of them had sores upon their hands, and some degree of general indisposition, preceded by pains and tumours in the axillas: but there was no comparison in the severity of the disease as it was felt by the servant man, who had escaped the smallpox, and by those of the family who had not, for, while he was confined to his bed, they were able, without much inconvenience, to follow their ordinary business. February the 13th, 1797, I availed myself of an opportunity of inoculating William Rodway, the servant man above alluded to. Variolous matter was inserted into both his arms: in the right, by means of superficial incisions, and into the left by slight punctures into the cutis. Both were perceptibly inflamed on the third day. After this the inflammation about the punctures soon died away, but a small appearance of erysipelas was manifest about the edges of the incisions till the eighth day, when a little uneasiness was felt for the space of half an hour in the right axilla. The inflammation then hastily disappeared without producing the most distant mark of affection of the system. CASE VIII.--Elizabeth Wynne, aged fifty-seven, lived as a servant with a neighbouring farmer thirty-eight years ago. She was then a dairymaid, and the cow-pox broke out among the cows. She caught the disease with the rest of the family, but, compared with them, had it in a very slight degree, one very small sore only breaking out on the little finger of her left hand, and scarcely any perceptible indisposition, following it. As the malady had shewn itself in so slight a manner, and as it had taken place at so distant a period of her life, I was happy with the opportunity of trying the effects of variolous matter upon her constitution, and on the 28th of March, 1797, I inoculated her by making two superficial incisions on the left arm, on which the matter was cautiously rubbed. A little efflorescence soon appeared, and a tingling sensation was felt about the parts where the matter was inserted until the third day, when both began to subside, and so early as the fifth day it was evident that no indisposition would follow. CASE IX.--Although the cow-pox shields the constitution from the smallpox, and the smallpox proves a protection against its own future poison, yet it appears that the human body is again and again susceptible of the infectious matter of the cow-pox, as the following history will demonstrate. William Smith, of Pyrton in this parish, contracted this disease when he lived with a neighbouring farmer in the year 1780. One of the horses belonging to the farm had sore heels, and it fell to his lot to attend him. By these means the infection was carried to the cows, and from the cows it was communicated to Smith. On one of his hands were several ulcerated sores, and he was affected with such symptoms as have been before described. In the year 1791 the cow-pox broke out at another farm where he then lived as a servant, and he became affected with it a second time; and in the year 1794 he was so unfortunate as to catch it again. The disease was equally as severe the second and third time as it was on the first. [Footnote: This is not the case in general--a second attack is commonly very slight, and so, I am informed, it is among the cows.] In the spring of the year 1795 he was twice inoculated, but no affection of the system could be produced from the variolous matter; and he has since associated with those who had the smallpox in its most contagious state without feeling any effect from it. CASE X.--Simon Nichols lived as a servant with Mr. Bromedge, a gentleman who resides on his own farm in this parish, in the year 1782. He was employed in applying dressings to the sore heels of one of his master's horses, and at the same time assisted in milking the cows. The cows became affected in consequence, but the disease did not shew itself on their nipples till several weeks after he had begun to dress the horse. He quitted Mr. Bromedge's service, and went to another farm without any sores upon him; but here his hands soon began to be affected in the common way, and he was much indisposed with the usual symptoms. Concealing the nature of the malady from Mr. Cole, his new master, and being there also employed in milking, the cowpox was communicated to the cows. Some years afterward Nichols was employed in a farm where the smallpox broke out, when I inoculated him with several other patients, with whom he continued during the whole time of their confinement. His arm inflamed, but neither the inflammation nor his associating with the inoculated family produced the least effect upon his constitution. CASE XI.--William Stinchcomb was a fellow servant with Nichols at Mr. Bromedge's farm at the time the cattle had the cow-pox, and he was, unfortunately, infected by them. His left hand was very severely affected with several corroding ulcers, and a tumour of considerable size appeared in the axilla of that side. His right hand had only one small tumour upon it, and no sore discovered itself in the corresponding axilla. In the year 1792 Stinchcomb was inoculated with variolous matter, but no consequences ensued beyond a little inflammation in the arm for a few days. A large party were inoculated at the same time, some of whom had the disease in a more violent degree than is commonly seen from inoculation. He purposely associated with them, but could not receive the smallpox. During the sickening of some of his companions their symptoms so strongly recalled to his mind his own state when sickening with the cow--pox that he very pertinently remarked their striking similarity. CASE XII.--The paupers of the village of Tortworth, in this county, were inoculated by Mr. Henry Jenner, Surgeon, of Berkeley, in the year 1795. Among them, eight patients presented themselves who had at different periods of their lives had the cow-pox. One of them, Hester Walkley, I attended with that disease when she lived in the service of a farmer in the same village in the year 1782; but neither this woman, nor any other of the patients who had gone through the cow-pox, received the variolous infection either from the arm or from mixing in the society of the other patients who were inoculated at the same time. This state of security proved a fortunate circumstance, as many of the poor women were at the same time in a state of pregnancy. CASE XIII.--One instance has occurred to me of the system being affected from the matter issuing from the heels of horses, and of its remaining afterwards unsusceptible of the variolous contagion; another, where the smallpox appeared obscurely; and a third, in which its complete existence was positively ascertained. First, Thomas Pearce is the son of a smith and farrier near to this place. He never had the cow-pox; but, in consequence of dressing horses with sore heels at his father's, when a lad, he had sores on his fingers which suppurated, and which occasioned a pretty severe indisposition. Six years afterwards I inserted variolous matter into his arm repeatedly, without being able to produce any thing more than slight inflammation, which appeared very soon after the matter was applied, and afterwards I exposed him to the contagion of the smallpox with as little effect. [Footnote: It is a remarkable fact, and well known to many, that we are frequently foiled in our endeavours to communicate the smallpox by inoculation to blacksmiths, who in the country are farriers. They often, as in the above instance, either resist the contagion entirely, or have the disease anomalously. Shall we not be able to account for this on a rational principle?] CASE XIV.--Secondly, Mr. James Cole, a farmer in this parish, had a disease from the same source as related in the preceding case, and some years after was inoculated with variolous matter. He had a little pain in the axilla and felt a slight indisposition for three or four hours. A few eruptions shewed themselves on the forehead, but they very soon disappeared without advancing to maturation. CASE XV.--Although in the former instances the system seemed to be secured, or nearly so, from variolous infection, by the absorption of matter from the sores produced by the diseased heels of horses, yet the following case decisively proves that this cannot be entirely relied upon until a disease has been generated by the morbid matter from the horse on the nipple of the cow, and passed through that medium to the human subject. Mr. Abraham Riddiford, a farmer at Stone in this parish, in consequence of dressing a mare that had sore heels, was affected with very painful sores in both his hands, tumours in each axilla, and severe and general indisposition. A surgeon in the neighbourhood attended him, who knowing the similarity between the appearance of the sores upon his hands and those produced by the cow-pox, and being acquainted also with the effects of that disease on the human constitution, assured him that he never need to fear the infection of the smallpox; but this assertion proved fallacious, for, on being exposed to the infection upwards of twenty years afterwards, he caught the disease, which took its regular course in a very mild way. There certainly was a difference perceptible, although it is not easy to describe it, in the general appearance of the pustules from that which we commonly see. Other practitioners who visited the patient at my request agreed with me in this point, though there was no room left for suspicion as to the reality of the disease, as I inoculated some of his family from the pustules, who had the smallpox, with its usual appearances, in consequence. CASE XVI.--Sarah Nelmes, a dairymaid at a farmer's near this place, was infected with the cow-pox from her master's cows in May, 1796. She received the infection on a part of her hand which had been previously in a slight degree injured by a scratch from a thorn. A large pustulous sore and the usual symptoms accompanying the disease were produced in consequence. The pustule was so expressive of the true character of the cow-pox, as it commonly appears upon the hand, that I have given a representation of it in the annexed plate. The two small pustules on the wrists arose also from the application of the virus to some minute abrasions of the cuticle, but the livid tint, if they ever had any, was not conspicuous at the time I saw the patient. The pustule on the forefinger shews the disease in an earlier stage. It did not actually appear on the hand of this young woman, but was taken from that of another, and is annexed for the purpose of representing the malady after it has newly appeared. CASE XVII.--The more accurately to observe the progress of the infection I selected a healthy boy, about eight years old, for the purpose of inoculation for the cow-pox. The matter was taken from a sore on the hand of a dairymaid [Footnote: From the sore on the hand of Sarah Nelmes. See the preceding case.], who was infected by her master's cows, and it was inserted, on the 14th of May, 1796, into the arm of the boy by means of two superficial incisions, barely penetrating the cutis, each about half an inch long. On the seventh day he complained of uneasiness in the axilla, and on the ninth he became a little chilly, lost his appetite, and had a slight headache. During the whole of this day he was perceptibly indisposed, and spent the night with some degree of restlessness, but on the day following he was perfectly well. The appearance of the incisions in their progress to a state of maturation were much the same as when produced in a similar manner by variolous matter. The only difference which I perceived was in the state of the limpid fluid arising from the action of the virus, which assumed rather a darker hue, and in that of the efflorescence spreading round the incisions, which had more of an erysipelatous look than we commonly perceive when variolous matter has been made use of in the same manner; but the whole died away (leaving on the inoculated parts scabs and subsequent eschars) without giving me or my patient the least trouble. In order to ascertain whether the boy, after feeling so slight an affection of the system from the cow--pox virus, was secure from the contagion of the smallpox, he was inoculated the 1st of July following with variolous matter, immediately taken from a pustule. Several slight punctures and incisions were made on both his arms, and the matter was carefully inserted, but no disease followed. The same appearances were observable on the arms as we commonly see when a patient has had variolous matter applied, after having either the cow--pox or smallpox. Several months afterwards he was again inoculated with variolous matter, but no sensible effect was produced on the constitution. Here my researches were interrupted till the spring of the year 1798, when, from the wetness of the early part of the season, many of the farmers' horses in this neighbourhood were affected with sore heels, in consequence of which the cow--pox broke out among several of our dairies, which afforded me an opportunity of making further observations upon this curious disease. A mare, the property of a person who keeps a dairy in a neighbouring parish, began to have sore heels the latter end of the month of February, 1798, which were occasionally washed by the servant men of the farm, Thomas Virgoe, William Wherret, and William Haynes, who in consequence became affected with sores in their hands, followed by inflamed lymphatic glands in the arms and axillae, shiverings succeeded by heat, lassitude, and general pains in the limbs. A single paroxysm terminated the disease; for within twenty--four hours they were free from general indisposition, nothing remaining but the sores on their hands. Haynes and Virgoe, who had gone through the smallpox from inoculation, described their feelings as very similar to those which affected them on sickening with that malady. Wherret never had had the smallpox. Haynes was daily employed as one of the milkers at the farm, and the disease began to shew itself among the cows about ten days after he first assisted in washing the mare's heels. Their nipples became sore in the usual way, with bluish pustules; but as remedies were early applied, they did not ulcerate to any extent. CASE XVIII.--John Baker, a child of five years old, was inoculated March 16, 1798, with matter taken from a pustule on the hand of Thomas Virgoe, one of the servants who had been infected from the mare's heels. He became ill on the sixth day with symptoms similar to those excited by cow--pox matter. On the eighth day he was free from indisposition. There was some variation in the appearance of the pustule on the arm. Although it somewhat resembled a smallpox pustule, yet its similitude was not so conspicuous as when excited by matter from the nipple of the cow, or when the matter has passed from thence through the medium of the human subject. This experiment was made to ascertain the progress and subsequent effects of the disease when thus propagated. We have seen that the virus from the horge, when it proves infectious to the human subject, is not to be relied upon as rendering the system secure from variolous infection, but that the matter produced by it upon the nipple of the cow is perfectly so. Whether its passing from the horse through the human constitution, as in the present instance, will produce a similar effect, remains to be decided. This would mow have been effected, but the boy was rendered unit for inoculation from having felt the effects of a contagious fever in a workhouse soon after this experiment was made. CASE XIX.--William Summers, a child of five years and a half old, was inoculated the same day with Baker, with matter taken from the nipples of one of the infected cows, at the farm alluded to. He became indisposed on the sixth day, vomited once, and felt the usual slight symptoms till the eighth day, when he appeared perfectly well. The progress of the pustule, formed by the infection of the virus, was similar to that noticed in Case XVII, with this exception, its being free from the livid tint observed in that instance. CASE XX.-From William Summers the disease was transferred to William Pead, a boy of eight years old, who was inoculated March 28th. On the sixth day he complained of pain in the axilla, and on the seventh was affected with the common symptoms of a patient sickening with the smallpox from inoculation, which did not terminate till the third day after the seizure. So perfect was the similarity to the variolous fever that I was induced to examine the skin, conceiving there might have been some eruptions, but none appeared. The efflorescent blush around the part punctured in the boy's arm was so truly characteristic of that which appears on variolous inoculation that I have given a representation of it. The drawing was made when the pustule was beginning to die away and the areola retiring from the centre. CASE XXI.-April 5th: Several children and adults were inoculated from the arm of William Pead. The greater part of them sickened on the sixth day, and were well on the seventh, but in three of the number a secondary indisposition arose in consequence of an extensive erysipelatous inflammation which appeared on the inoculated arms. It seemed to arise from the state of the pustule, which spread out, accompanied with some degree of pain, to about half the diameter of a sixpence. One of these patients was an infant of half a year old. By the application of mercurial ointment to the inflamed parts (a treatment recommended under similar circumstances in the inoculated smallpox) the complaint subsided without giving much trouble. Hannah Excell, an healthy girl of seven years old, and one of the patients above mentioned, received the infection from the insertion of the virus under the cuticle of the arm in three distinct points. The pustules which arose in consequence so much resembled, on the twelfth day, those appearing from the infection of variolous matter, that an experienced inoculator would scarcely have discovered a shade of difference at that period. Experience now tells me that almost the only variation which follows consists in the pustulous fluids remaining limpid nearly to the time of its total disappearance; and not, as in the direct smallpox, becoming purulent. CASE XXII.--From the arm of this girl matter was taken and inserted April 12th into the arms of John Macklove, one year and a half old, Robert F. Jenner, eleven months old, Mary Pead, five years old, and Mary James, six years old. [Footnote: Perhaps a few touches with the lapis septicus would have proved equally efficacious.] Among these, Robert F. Jenner did not receive the infection. The arms of the other three inflamed properly and began to affect the system in the usual manner; but being under some apprehensions from the preceding cases that a troublesome erysipelas might arise, I determined on making an experiment with the view of cutting off its source. Accordingly, after the patients had felt an indisposition of about twelve hours, I applied in two of these cases out of the three, on the vesicle formed by the virus, a little mild caustic, composed of equal parts of quick--lime and soap, and suffered it to remain on the part six hours. [Footnote: What effect would a similar treatment produce in inoculation for the smallpox?] It seemed to give the children but little uneasiness, and effectually answered my intention in preventing the appearance of erysipelas. Indeed, it seemed to do more, for in half an hour after its application the indisposition of the children ceased. These precautions were perhaps unnecessary, as the arm of the third child, Mary Pead, which was suffered to take its common course, scabbed quickly, without any erysipelas. CASE XXIII.--From this child's arm matter was taken and transferred to that of J. Barge, a boy of seven years old. He sickened on the eighth day, went through the disease with the usual slight symptoms, and without any inflammation on the arm beyond the common efflorescence surrounding the pustule, an appearance so often seen in inoculated smallpox. After the many fruitless attempts to give the smallpox to those who had had the cow-pox, it did not appear necessary, nor was it convenient to me, to inoculate the whole of those who had been the subjects of these late trials; yet I thought it right to see the effects of variolous matter on some of them, particularly William Summers, the first of these patients who had been infected with matter taken from the cow. He was, therefore, inoculated with variolous matter from a fresh pustule; but, as in the preceding cases, the system did not feel the effects of it in the smallest degree. I had an opportunity also of having this boy and William Pead inoculated by my nephew, Mr. Henry Jenner, whose report to me is as follows: "I have inoculated Pead and Barge, two of the boys whom you lately infected with the cow-pox. On the second day the incisions were inflamed and there was a pale inflammatory stain around them. On the third day these appearances were still increasing and their arms itched considerably. On the fourth day the inflammation was evidently subsiding, and on the sixth day it was scarcely perceptible. No symptom of indisposition followed. "To convince myself that the variolous matter made use of was in a perfect state I at the same time inoculated a patient with some of it who never had gone through the cow-pox, and it produced the smallpox in the usual regular manner." These experiments afforded me much satisfaction; they proved that the matter, in passing from one human subject to another, through five gradations, lost none of its original properties, J. Barge being the fifth who received the infection successively from William Summers, the boy to whom it was communicated from the cow. I shall now conclude this inquiry with some general observations on the subject, and on some others which are interwoven with it. Although I presume it may be unnecessary to produce further testimony in support of my assertion "that the cow--pox protects the human constitution from the infection of the smallpox," yet it affords me considerable satisfaction to say that Lord Somerville, the President of the Board of Agriculture, to whom this paper was shewn by Sir Joseph Banks, has found upon inquiry that the statements were confirmed by the concurring testimony of Mr. Dolland, a surgeon, who resides in a dairy country remote from this, in which these observations were made. With respect to the opinion adduced "that the source of the infection is a peculiar morbid matter arising in the horse," although I have not been able to prove it from actual experiments conducted immediately under my own eye, yet the evidence I have adduced appears sufficient to establish it. They who are not in the habit of conducting experiments may not be aware of the coincidence of circumstances necessary for their being managed so as to prove perfectly decisive; nor how often men engaged in professional pursuits are liable to interruptions which disappoint them almost at the instant of their being accomplished: however, I feel no room for hesitation respecting the common origin of the disease, being well convinced that it never appears among the cows (except it can be traced to a cow introduced among the general herd which has been previously infected, or to an infected servant) unless they have been milked by some one who, at the same time, has the care of a horse affected with diseased heels. The spring of the year 1797, which I intended particularly to have devoted to the completion of this investigation, proved, from its dryness, remarkably adverse to my wishes;-for it frequently happens, while the farmers' horses are exposed to the cold rains which fall at that season, that their heels become diseased, and no cow-pox then appeared in the neighbourhood. The active quality of the virus from the horses' heels is greatly increased after it has acted on the nipples of the cow, as it rarely happens that the horse affects his dresser with sores, and as rarely that a milkmaid escapes the infection when she milks infected cows. It is most active at the commencement of the disease, even before it has acquired a pus-like appearance; indeed, I am not confident whether this property in the matter does not entirely cease as soon as it is secreted in the form of pus. I am induced to think it does cease [Footnote: It is very easy to procure pus from old sores on the heels of horses. This I have often inserted into scratches made with a lancet, on the sound nipples of cows, and have seen no other effects from it than simple inflamation.], and that it is the thin, darkish- looking fluid only, oozing from the newly-formed cracks in the heels, similar to what sometimes appears from erysipelatous blisters, which gives the disease. Nor am I certain that the nipples of the cows are at all times in a state to receive the infection. The appearance of the disease in the spring and the early part of the summer, when they are disposed to be affected with spontaneous eruptions so much more frequently than at other seasons, induces me to think that the virus from the horse must be received upon them when they are in this state, in order to produce effects: experiments, however, must determine these points. But it is clear that when the cow-pox virus is once generated, that the cows cannot resist the contagion, in whatever state their nipples may chance to be, if they are milked with an infected hand. Whether the matter, either from the cow or the horse, will affect the sound skin of the human body, I cannot positively determine; probably it will not, unless on those parts where the cuticle is extremely thin, as on the lips, for example. I have known an instance of a poor girl who produced an ulceration on her lip by frequently holding her finger to her mouth to cool the raging of a cow-pox sore by blowing upon it. The hands of the farmers' servants here, from the nature of their employments, are constantly exposed to those injuries which occasion abrasions of the cuticle, to punctures from thorns, and such like accidents; so that they are always in a state to feel the consequence of exposure to infectious matter. It is singular to observe that the cow--pox virus, although it renders the constitution unsusceptible of the variolous, should nevertheless, leave it unchanged with respect to its own action. I have already produced an instance [Footnote: See Case IX.] to point out this, and shall now corroborate it with another. Elizabeth Wynne, who had the cow-pox in the year 1759, was inoculated with variolous matter, without effect, in the year 1797, and again caught the cow-pox in the year 1798. When I saw her, which was on the eighth day after she received the infection, I found her affected with general lassitude, shiverings, alternating with heat, coldness of the extremities, and a quick and irregular pulse. These symptoms were preceded by a pain in the axilla. On her hand was one large pustulous sore, which resembled that delineated in Plate No. I. (Plate appears in original.) It is curious also to observe that the virus, which with respect to its effects is undetermined and uncertain previously to its passing from the horse through the medium of the cow, should then not only become more active, but should invariably and completely possess those specific properties which induce in the human constitution symptoms similar to those of the variolous fever, and effect in it that peculiar change which for ever renders it unsusceptible of the variolous contagion. May it not then be reasonably conjectured that the source of the smallpox is morbid matter of a peculiar kind, generated by a disease in the horse, and that accidental circumstances may have again and again arisen, still working new changes upon it until it has acquired the contagious and malignant form under which we now commonly see it making its devastations amongst us? And, from a consideration of the change which the infectious matter undergoes from producing a disease on the cow, may we not conceive that many contagious diseases, now prevalent among us, may owe their present appearance not to a simple, but to a compound, origin? For example, is it difficult to imagine that the measles, the scarlet fever, and the ulcerous sore throat with a spotted skin have all sprung from the same source, assuming some variety in their forms according to the nature of their new combinations? The same question will apply respecting the origin of many other contagious diseases which bear a strong analogy to each other. There are certainly more forms than one, without considering the common variation between the confluent and distinct, in which the smallpox appears in what is called the natural way. About seven years ago a species of smallpox spread through many of the towns and villages of this part of Gloucestershire: it was of so mild a nature that a fatal instance was scarcely ever Heard of, and consequently so little dreaded by the lower orders of the community that they scrupled not to hold the same intercourse with each other as if no infectious disease had been present among them. I never saw nor heard of an instance of its being confluent. The most accurate manner, perhaps, in which I can convey an idea of it is by saying that had fifty individuals been taken promiscuously and infected by exposure to this contagion, they would have had as mild and light a disease as if they had been inoculated with variolous matter in the usual way. The harmless manner in which it shewed itself could not arise from any peculiarity either in the season or the weather, for I watched its progress upwards of a year without perceiving any variation in its general appearance. I consider it then as a variety of the smallpox. [Footnote: My friend, Dr. Hicks, of Bristol, who, during the prevalence of this distemper, was resident at Gloucester, and physician of the hospital there (where it was soon after its first appearance in this country), had opportunities of making numerous observations upon it, which it is his intention to communicate to the public.]. In some of the preceding cases I have noticed the attention that was paid to the state of the variolous matter previous to the experiment of inserting it into the arms of those who had gone through the cow-pox. This I conceived to be of great importance in conducting these experiments, and, were it always properly attended to by those who inoculate for the smallpox, it might prevent much subsequent mischief and confusion. With the view of enforcing so necessary a precaution I shall take the liberty of digressing so far as to point out some unpleasant facts relative to mismanagement in this particular, which have fallen under my own observation. A medical gentleman (now no more), who for many years inoculated in this neighbourhood, frequently preserved the variolous matter intended for his use on a piece of lint or cotton, which, in its fluid state, was put into a vial, corked, and conveyed into a warm pocket; a situation certainly favourable for speedily producing putrefaction in it. In this state (not unfrequently after it had been taken several days from the pustules) it was inserted into the arms of his patients, and brought on inflammation of the incised parts, swellings of the axillary glands, fever, and sometimes eruptions. But what was this disease? Certainly not the smallpox; for the matter having from putrefaction lost or suffered a derangement in its specific properties, was no longer capable of producing that malady, those who had been inoculated in this manner being as much subject to the contagion of the smallpox as if they had never been under the influence of this artificial disease; and many, unfortunately, fell victims to it, who thought themselves in perfect security. The same unfortunate circumstance of giving a disease, supposed to be the smallpox, with inefficacious variolous matter, having occurred under the direction of some other practitioners within my knowledge, and probably from the same incautious method of securing the variolous matter, I avail myself of this opportunity of mentioning what I conceive to be of great importance; and, as a further cautionary hint, I shall again digress so far as to add another observation on the subject of inoculation. Whether it be yet ascertained by experiment that the quantity of variolous matter inserted into the skin makes any difference with respect to the subsequent mildness or violence of the disease, I know not; but I have the strongest reason for supposing that if either the punctures or incisions be made so deep as to go through it and wound the adipose membrane, that the risk of bringing on a violent disease is greatly increased. I have known an inoculator whose practice was "to cut deep enough (to use his own expression) to see a bit of fat." and there to lodge the matter. The great number of bad cases, independent of inflammations and abscesses on the arms, and the fatality which attended this practice, was almost inconceivable; and I cannot account for it on any other principle than that of the matter being placed in this situation instead of the skin. It was the practice of another, whom I well remember, to pinch up a small portion of the skin on the arms of his patients and to pass through it a needle, with a thread attached to it previously dipped in variolous matter. The thread was lodged in the perforated part, and consequently left in contact with the cellular membrane. This practice was attended with the same ill success as the former. Although it is very improbable that any one would now inoculate in this rude way by design, yet these observations may tend to place a double guard over the lancet, when infants, whose skins are comparatively so very thin, fall under the care of the inoculator. A very respectable friend of mine, Dr. Hardwicke, of Sodbury, in this county, inoculated great numbers of patients previous to the introduction of the more modern method by Sutton, and with such success that a fatal instance occurred as rarely as since that method has been adopted. It was the doctor's practice to make as slight an incision as possible upon the skin, and there to lodge a thread saturated with the variolous matter. When his patients became indisposed, agreeably to the custom then prevailing, they were directed to go to bed and were kept moderately warm. Is it not probable then that the success of the modern practice may depend more upon the method of invariably depositing the virus in or upon the skin, than on the subsequent treatment of the disease? I do not mean to insinuate that exposure to cool air, and suffering the patient to drink cold water when hot and thirsty, may not moderate the eruptive symptoms and lessen the number of pustules; yet, to repeat my former observation, I cannot account for the uninterrupted success, or nearly so, of one practitioner, and the wretched state of the patients under the care of another, where, in both instances, the general treatment did not differ essentially, without conceiving it to arise from the different modes of inserting the matter for the purpose of producing the disease. As it is not the identical matter inserted which is absorbed into the constitution, but that which is, by some peculiar process in the animal economy, generated by it, is it not probable that different parts of the human body may prepare or modify the virus differently? Although the skin, for example, adipose membrane, or mucous membranes are all capable of producing the variolous virus by the stimulus given by the particles originally deposited upon them, yet I am induced to conceive that each of these parts is capable of producing some variation in the qualities of the matter previous to its affecting the constitution. What else can constitute the difference between the smallpox when communicated casually or in what has been termed the natural way, or when brought on artificially through the medium of the skin? After all, are the variolous particles, possessing their true specific and contagious principles, ever taken up and conveyed by the lymphatics unchanged into the blood vessels? I imagine not. Were this the case, should we not find the blood sufficiently loaded with them in some stages of the smallpox to communicate the disease by inserting it under the cuticle, or by spreading it on the surface of an ulcer? Yet experiments have determined the impracticability of its being given in this way; although it has been proved that variolous matter, when much diluted with water and applied to the skin in the usual manner, will produce the disease. But it would be digressing beyond a proper boundary to go minutely into this subject here. At what period the cow-pox was first noticed here is not upon record. Our oldest farmers were not unacquainted with it in their earliest days, when it appeared among their farms without any deviation from the phaenomena which it now exhibits. Its connection with the smallpox seems to have been unknown to them. Probably the general introduction of inoculation first occasioned the discovery. Its rise in this country may not have been of very remote date, as the practice of milking cows might formerly have been in the hands of women only; which I believe is the case now in some other dairy countries, and, consequently, that the cows might not in former times have been exposed to the contagious matter brought by the men servants from the heels of horses. [Footnote: I have been informed from respectable authority that in Ireland, although dairies abound in many parts of the island, the disease is entirely unknown. The reason seems obvious. The business of the dairy is conducted by women only. Were the meanest vassal among the men employed there as a milker at a dairy, he would feel his situation unpleasant beyond all endurance.] Indeed, a knowledge of the source of the infection is new in the minds of most of the farmers in this neighbourhood, but it has at length produced good consequences; and it seems probable, from the precautions they are now disposed to adopt, that the appearance of the cow-pox here may either be entirely extinguished or become extremely rare. Should it be asked whether this investigation is a matter of mere curiosity, or whether it tends to any beneficial purpose, I should answer that, notwithstanding the happy effects of inoculation, with all the improvements which the practice has received since its first introduction into this country, it not very unfrequently produces deformity of the skin, and sometimes, under the best management, proves fatal. These circumstances must naturally create in every instance some degree of painful solicitude for its consequences. But as I have never known fatal effects arise from the cow-pox, even when impressed in the most unfavourable manner, producing extensive inflammations and suppurations on the hands; and as it clearly appears that this disease leaves the constitution in a state of perfect security from the infection of the smallpox, may we not infer that a mode of inoculation may be introduced preferable to that at present adopted, especially among those families which, from previous circumstances, we may judge to be predisposed to have the disease unfavourably? It is an excess in the number of pustules which we chiefly dread in the smallpox; but in the cow- pox no pustules appear, nor does it seem possible for the contagious matter to produce the disease from effluvia, or by any other means than contact, and that probably not simply between the virus and the cuticle; so that a single individual in a family might at any time receive it without the risk of infecting the rest or of spreading a distemper that fills a country with terror. Several instances have come under my observation which justify the assertion that the disease cannot be propagated by effluvia. The first boy whom I inoculated with the matter of cow-pox slept in a bed, while the experiment was going forward, with two children who never had gone through either that disease or the smallpox, without infecting either of them. A young woman who had the cow-pox to a great extent, several sores which maturated having appeared on the hands and wrists, slept in the same bed with a fellow-dairymaid who never had been infected with either the cow-pox or the smallpox, but no indisposition followed. Another instance has occurred of a young woman on whose hands were several large suppurations from the cow-pox, who was at the same time a daily nurse to an infant, but the complaint was not communicated to the child. In some other points of view the inoculation of this disease appears preferable to the variolous inoculation. In constitutions predisposed to scrophula, how frequently we see the inoculated smallpox rouse into activity that distressful malady! This circumstance does not seem to depend on the manner in which the distemper has shewn itself, for it has as frequently happened among those who have had it mildly as when it has appeared in the contrary way. There are many who, from some peculiarity in the habit, resist the common effects of variolous matter inserted into the skin, and who are in consequence haunted through life with the distressing idea of being insecure from subsequent infection. A ready mode of dissipating anxiety originating from such a cause must now appear obvious. And, as we have seen that the constitution may at any time be made to feel the febrile attack of cow-pox, might it not, in many chronic diseases, be introduced into the system, with the probability of affording relief, upon well-known physiological principles? Although I say the system may at any time be made to feel the febrile attack of cow-pox, yet I have a single instance before me where the virus acted locally only, but it is not in the least probable that the same person would resist the action both of the cow-pox virus and the variolous. Elizabeth Sarfenet lived as a dairymaid at Newpark farm, in this parish. All the cows and the servants employed in milking had the cow-pox; but this woman, though she had several sores upon her fingers, felt no tumours in the axillae, nor any general indisposition. On being afterwards casually exposed to variolous infection, she had the smallpox in a mild way. Hannah Pick, another of the dairymaids who was a fellow-servant with Elizabeth Sarfenet when the distemper broke out at the farm, was, at the same time, infected; but this young woman had not only sores upon her hands, but felt herself also much indisposed for a day or two. After this, I made several attempts to give her the smallpox by inoculation, but they all proved fruitless. From the former case then we see that the animal economy is subject to the same laws in one disease as the other. The following case, which has very lately occurred, renders it highly probable that not only the heels of the horse, but other parts of the body of that animal, are capable of generating the virus which produces the cow-pox. An extensive inflammation of the erysipelatous kind appeared without any apparent cause upon the upper part of the thigh of a sucking colt, the property of Mr. Millet, a farmer at Rockhampton, a village near Berkeley. The inflammation continued several weeks, and at length terminated in the formation of three or four small abscesses. The inflamed parts were fomented, and dressings were applied by some of the same persons who were employed in milking the cows. The number of cows milked was twenty-four, and the whole of them had the cow-pox. The milkers, consisting of the farmer's wife, a man and a maidservant, were infected by the cows. The man-servant had previously gone through the smallpox, and felt but little of the cow-pox. The servant maid had some years before been infected with the cow-pox, and she also felt it now in a slight degree; but the farmer's wife, who never had gone through either of the diseases, felt its effects very severely. That the disease produced upon the cows by the colt and from thence conveyed to those who milked them was the TRUE and not the SPURIOUS cow-pox, there can be scarcely any room for suspicion; yet it would have been more completely satisfactory had the effects of variolous matter been ascertained on the farmer's wife, but there was a peculiarity in her situation which prevented my making the experiment. Thus far have I proceeded in an inquiry founded, as it must appear, on the basis of experiment; in which, however, conjecture has been occasionally admitted in order to present to persons well situated for such discussions objects for a more minute investigation. In the mean time I shall myself continue to prosecute this inquiry, encouraged by the hope of its becoming essentially beneficial to mankind. II FURTHER OBSERVATIONS ON THE VARIOLA VACCINAE, OR COW-POX. 1799 Although it has not been in my power to extend the inquiry into the causes and effects of the variolae vaccinae much beyond its original limits, yet, perceiving that it is beginning to excite a general spirit of investigation, I think it of importance, without delay, to communicate such facts as have since occurred, and to point out the fallacious sources from whence a disease imitative of the true variolae vaccinae might arise, with the view of preventing those who may inoculate from producing a spurious disease; and, further, to enforce the precaution suggested in the former treatise on the subject, of subduing the inoculated pustule as soon as it has sufficiently produced its influence on the constitution. From a want of due discrimination of the real existence of the disease, either in the brute or in the human subject, and also of that stage of it in which it is capable of producing the change in the animal economy which renders it unsusceptible of the contagion of the smallpox, unpleasant consequences might ensue, the source of which, perhaps, might not be suspected by one inexperienced in conducting such experiments. My late publication contains a relation of most of the facts which had come under my own inspection at the time it was written, interspersed with some conjectural observations. Since then Dr. G. Pearson has established an inquiry into the validity of my principal assertion, the result of which cannot but be highly flattering to my feelings. It contains not a single case which I think can be called an exception to the fact I was so firmly impressed with--that the cow-pox protects the human body from the smallpox. I have myself received some further confirmations, which shall be subjoined. I have lately also been favoured with a letter from a gentleman of great respectability (Dr. Ingenhousz), informing me that, on making an inquiry into the subject in the county of Wilts, he discovered that a farmer near Calne had been infected with the smallpox after having had the cow-pox, and that the disease in each instance was so strongly characterized as to render the facts incontrovertible. The cow-pox, it seems, from the doctor's information, was communicated to the farmer from his cows at the time that they gave out an offensive stench from their udders. Some other instances have likewise been represented to me of the appearance of the disease, apparently marked with its characteristic symptoms, and yet that the patients have afterwards had the smallpox. On these cases I shall, for the present, suspend any particular remarks, but hope that the general observations I have to offer in the sequel will prove of sufficient weight to render the idea of their ever having had existence, but as cases of spurious cow-pox, extremely doubtful. Ere I proceed let me be permitted to observe that truth, in this and every other physiological inquiry that has occupied my attention, has ever been the object of my pursuit, and should it appear in the present instance that I have been led into error, fond as I may appear of the offspring of my labours, I had rather see it perish at once than exist and do a public injury. I shall proceed to enumerate the sources, or what appear to me as such, of a spurious cow-pox. First: That arising from pustules on the nipples or udder of the cow; which pustules contain no specific virus. Secondly: From matter (although originally possessing the specific virus) which has suffered a decomposition, either from putrefaction or from any other cause less obvious to the senses. Thirdly: From matter taken from an ulcer in an advanced stage, which ulcer arose from a true cow pock. Fourthly: From matter produced on the human skin from contact with some peculiar morbid matter generated by a horse. On these subjects I shall offer some comments: First, to what length pustulous diseases of the udder and nipples of the cow may extend it is not in my power to determine; but certain it is that these parts of the animal are subject to some variety of maladies of this nature; and as many of these eruptions (probably all of them) are capable of giving a disease to the human body, would it not be discreet for those engaged in this investigation to suspend controversy and cavil until they can ascertain with precision what IS and what IS NOT the cow-pox? For example: A farmer who is not conversant with any of these maladies, but who may have heard of the cow-pox in general terms, may acquaint a neighbouring surgeon that the distemper appears at his farm. The surgeon, eager to make an experiment, takes away matter, inoculates, produces a sore, uneasiness in the axilla, and perhaps some affection of the system. This is one way in which a fallacious idea of security both in the mind of the inoculater and the patient may arise; for a disease may thus have been propagated from a simple eruption only. One of the first objects then of this pursuit, as I have observed, should be, to learn how to distinguish with accuracy between that peculiar pustule which is the true cow pock, and that which is spurious. Until experience has determined this, we view our object through a mist. Let us, for instance, suppose that the smallpox and the chicken-pox were at the same time to spread among the inhabitants of a country which had never been visited by either of these distempers, and where they were quite unknown before: what confusion would arise! The resemblance between the symptoms of the eruptive fever and between the pustules in either case would be so striking that a patient who had gone through the chicken-pox to any extent would feel equally easy with regard to his future security from the smallpox as the person who had actually passed through that disease. Time and future observation would draw the line of distinction. So I presume it will be with the cow-pox until it is more generally understood. All cavilling, therefore, on the mere report of those who TELL US they have had this distemper, and are afterwards found susceptible of the smallpox, should be suspended. To illustrate this I beg leave to give the following history: Sarah Merlin, of the parish of Eastington in this county, when about thirteen or fourteen years of age lived as a servant with farmer Clarke, who kept a dairy consisting of about eighteen cows at Stonehouse, a neighbouring village. The nipples and udders of three of the cows were extensively affected with large white blisters. These cows the girl milked daily, and at the time she assisted, with two others, in milking the rest of the herd. It soon appeared that the disease was communicated to the girl. The rest of the cows escaped the infection, although they were milked several days after the three above specified, had these eruptions on the nipples and udders, and even after the girl's hand became sore. The two others who were engaged in milking, although they milked the cows indiscriminately, received no injury. On the fingers of each of the girl's hands there appeared several large white blisters--she supposes about three or four on each finger. The hands and arms inflamed and swelled, but no constitutional indisposition followed. The sores were anointed with some domestic ointment and got well without ulcerating. As this malady was called the cow-pox, and recorded as such in the mind of the patient, she became regardless of the smallpox; but, on being exposed to it some years afterwards she was infected, and had a full burthen. Now had any one conversant with the habits of the disease heard this history, they would have had no hesitation in pronouncing it a case of spurious cow-pox; considering its deviation in the NUMEROUS blisters which appeared on the girl's hands; their termination without ulceration; its not proving more generally contagious at the farm, either among the cattle or those employed in milking; and considering also that THE PATIENT FELT NO GENERAL INDISPOSITION, ALTHOUGH THERE WAS SO GREAT A NUMBER OF VESICLES. This is perhaps the most deceptious form in which an eruptive disease can be communicated from the cow, and it certainly requires some attention in discriminating it. The most perfect criterion by which the judgment may be guided is perhaps that adopted by those who attend infected cattle. These white blisters on the nipples, they say, NEVER EAT INTO THE FLESHY PARTS like those which are commonly of a bluish cast, and which constitute the TRUE COW-POX, but that they affect the skin only, quickly end in scabs, and are not nearly so infectious. That which appeared to me as one cause of spurious eruptions, I have already remarked in the former treatise, namely, the transition that the cow makes in the spring from a poor to a nutritious diet, and from the udder's becoming at this time more vascular than usual for the supply of milk. But there is another source of inflammation and pustules which I believe is not uncommon in all the dairy counties in the west of England. A cow intended to be exposed for sale, having naturally a small udder, is previously for a day or two neither milked artificially nor is her calf suffered to have access to her. Thus the milk is preternaturally accumulated, and the udder and nipples become greatly distended. The consequences frequently are inflammation and eruptions which maturate. Whether a disease generated in this way has the power of affecting the constitution in any PECULIAR manner I cannot presume positively to determine. It has been conjectured to have been a cause of the true cow-pox, though my inquiries have not led me to adopt this supposition in any one instance; on the contrary, I have known the milkers affected by it, but always found that an affection thus induced left the system as susceptible of the smallpox as before. What is advanced in my second position I consider also of very great importance, and I could wish it to be strongly impressed on the minds of all who may be disposed to conclude hastily on my observations, whether engaged in their investigation by experiments or not to place this in its clearest point of view (as the similarity between the action of the smallpox and the cow-pox matter is so obvious) it will be necessary to consider what we sometimes observe to take place in inoculation for the smallpox when imperfect variolous matter is made use of. The concise history on this subject that was brought forward respecting what I had observed in this neighbourhood [Footnote: Inquiry into the Causes and Effects of the Variolae Vaccinae, p.56 of the original article]. I perceive, by a reference since made to the Memoirs of the Medical Society of London, may be considered as no more than a corroboration of the facts very clearly detailed by Mr. Kite [Footnote: See an account of some anomalous appearances consequent to the inoculation of the smallpox, by Charles Kite, Surgeon, of Gravesend, in the Memoirs of the Medical Society of London, vol. iv, p. 114.]. To this copious evidence I have to add still more in the following communications from Mr. Earle, surgeon, of Frampton-upon-Severn, in this county, which I deem the more valuable, as he has with much candour permitted me to make them public: "SIR: "I have read with satisfaction your late publication on the Variolae Vaccinae, and being, among many other curious circumstances, particularly struck with that relating to the inefficacy of smallpox matter in a particular state, I think it proper to lay before you the following facts which came within my own knowledge, and which certainly tend to strengthen the opinions advanced in pages 56 and 57 of your treatise. "In March, 1784, a general inoculation took place at Arlingham in this county. I inoculated several patients with active variolous matter, all of whom had the disease in a favourable way; but the matter being all used, and not being able to procure any more in the state I wished, I was under the necessity of taking it from a pustule which, experience has since proved, was advanced too far to answer the purpose I intended. Of five persons inoculated with this last matter, four took the smallpox afterwards in the natural way, one of whom died, three recovered, and the other, being cautioned by me to avoid as much as possible the chance of catching it, escaped from the disease through life. He died of another disorder about two years ago. "Although one of these cases ended unfortunate, yet I cannot suppose that any medical man will think me careless or inattentive in their management; for I conceive the appearances were such as might have induced any one to suppose that the persons were perfectly safe from future infection. Inflammation in every case took place in the arm, and fever came on with a considerable degree of pain in the axilla. In some of their arms the inflammation and suppuration were more violent than is commonly observed when perfect matter is made use of; in one there was an ulcer which cast off several large sloughs. About the ninth day eruptions appeared, which died away earlier than common without maturation. From these circumstances I should suppose that no medical practitioner would scarcely have entertained a doubt but that these patients had been infected with a true smallpox; yet I must confess that some small degree of doubt presented itself to me at the speedy disappearance of the eruptions; and in order, as far as I could, to ascertain their safety, I sent one of them to a much older practitioner than myself. This gentleman, on hearing the circumstances of the case, pronounced the patient perfectly secure from future infection. "The following facts are also a striking proof of the truth of your observations on this subject: "In the year 1789 I inoculated three children of Mr. Coaley, of Hurst farm in this county. The arms inflamed properly, fever and pain in the axillae came on precisely the same as in the former cases, and in ten days eruptions appeared, which disappeared in the course of two days. I must observe that the matter here made use of was procured for me by a friend; but no doubt it was in an improper state; for, from the similarity of these cases to those which happened at Arlingham five years before, I was somewhat alarmed for their safety, and desired to inoculate them again: which being permitted, I was particularly careful to procure matter in its most perfect state. All the children took the smallpox from this second inoculation, and all had a very full burthen. These facts I conceive strikingly corroborate your opinion relative to the different states of matter; for in both instances that I have mentioned it was capable of producing something strongly resembling the true smallpox, although it afterwards proved not to be so. "As I think the communication of these cases is a duty I owe to the public, you are at liberty to make what use you please of this letter. I remain, &c., "John Earle. "FRAMPTON-UPON SEVERN, GLOUCESTERSHIRE, November 10, 1798. "P. S. I think it necessary to observe that I can pronounce, with the greatest certainty, that the matter with which the Arlingham patients were inoculated was taken from a true smallpox pustule. I took it myself from a subject that had a very full burthen." Certain then it is that variolous matter may undergo such a change from the putrefactive process, as well as from some of the more obscure and latent processes of nature, as will render it incapable of giving the smallpox in such a manner as to secure the human constitution from future infection, although we see at the same time it is capable of exciting a disease which bears so strong a resemblance to it as to produce inflammation and matter in the incised skin (frequently, indeed, more violent than when it produces its effects perfectly), swelling of the axillary glands, general indisposition, and eruptions. So strongly persuaded was the gentleman, whose practice I have mentioned in page 56 of the late treatise, that he could produce a mild smallpox by his mode of managing the matter, that he spoke of it as a useful discovery until convinced of his error by the fatal consequence which ensued. After this ought we to be in the smallest degree surprised to find, among a great number of individuals who, by living in dairies, have been casually exposed to the cow-pox virus when in a state analogous to that of the smallpox above described, some who may have had the disease so imperfectly as not to render them secure from variolous attacks? For the matter, when burst from the pustules on the nipples of the cow, by being exposed, from its lodgment there, to the heat of an inflamed surface, and from being at the same time in a situation to be occasionally moistened with milk, is often likely to be in a state conducive to putrefaction; and thus, under some modification of decomposition, it must, of course, sometimes find access to the hand of the milker in such a way as to infect him. What confusion should we have were there no other mode of inoculating the smallpox than such as would happen from handling the diseased skin of a person labouring under that distemper in some of its advanced and loathsome stages! It must be observed that every case of cow-pox in the human species, whether communicated by design or otherwise, is to be considered as a case of inoculation. And here I may be allowed to make an observation on the case of the farmer communicated to me by Dr. Ingenhousz. That he was exposed to the matter when it had undergone the putrefactive change is highly probable from the doctor's observing that the sick cows at the farm gave out an OFFENSIVE STENCH FROM THEIR UDDERS. However, I must remark that it is unusual for cattle to suffer to such an extent, when disordered with the cowpox, as to make a bystander sensible of any ill smell. I have often stood among a herd which had the distemper without being conscious of its presence from any particular effluvia. Indeed, in this neighbourhood it commonly receives an early check from escharotic applications of the COW LEECH. It has been conceived to be contagious without contact; but this idea cannot be well founded because the cattle in one meadow do not infect those in another (although there may be no other partition than a hedge) unless they be handled or milked by those who bring the infectious matter with them; and of course, the smallest particle imaginable, when applied to a part susceptible of its influence, may produce the effect. Among the human species it appears to be very clear that the disease is produced by contact only. All my attempts, at least, to communicate it by effluvia have hitherto proved ineffectual. As well as the perfect change from that state in which variolous matter is capable of producing full and decisive effects on the constitution, to that wherein its specific properties are entirely lost, it may reasonably be supposed that it is capable of undergoing a variety of intermediate changes. The following singular occurrences in ten cases of inoculation, obligingly communicated to me by Mr. Trye, Senior Surgeon to the Infirmary at Glocester, seem to indicate that the variolous matter, previously to its being taken from the patient for the intended purpose, was beginning to part with some of its original properties, or, in other words, that it had suffered a partial decomposition. Mr. Trye says: "I inoculated ten children with matter taken at one time and from the same subject. I observed no peculiarity in any of them previously to their inoculation, nor did any thing remarkable appear in their arms till after the decline of the disease. Two infants of three months old had erysipelas about the incisions, in one of them extending from the shoulders to the fingers' ends. Another infant had abscesses in the cellular substance in the neighbourhood of the incisions, and five or six of the rest had axillary abscesses. The matter was taken from the distinct smallpox late in its progress, and when some pustules had been dried. It was received upon glass and slowly dried by the fire. All the children had pustules which maturated, so that I suppose them all secure from future infection; at least, as secure as any others whom I have ever inoculated. My practice never afforded a sore arm before." In regard to my former observation on the improper and dangerous mode of preserving variolous matter, I shall here remark that it seems not to have been clearly understood. Finding that it has been confounded with the more eligible modes of preservation, I will explain myself further. When the matter is taken from a fit pustule and properly prepared for preservation, it may certainly be kept without losing its specific properties a great length of time; for instance, when it is previously dried in the open air on some compact body, as a quill or a piece of glass, and afterwards secured in a small vial. [Footnote: Thus prepared, the cow-pox virus was found perfectly active, and possessing all its specific properties, at the end of three months.] But when kept several days in a state of moisture, and during that time exposed to a warm temperature, I do not think it can be relied upon as capable of giving a perfect disease, although, as I have before observed, the progress of the symptoms arising from the action of the imperfect matter bear so strong a resemblance to the smallpox when excited completely. Thirdly. That the first formed virus, or what constitutes the true cow-pox pustule, invariably possesses the power I have ascribed to it, namely, that of affecting the constitution with a specific disease, is a truth that no subsequent occurrence has yet led me to doubt. But as I am now endeavouring to guard the public as much as possible against erroneous conclusions, I shall observe that when this pustule has degenerated into an ulcer (to which state it is often disposed to pass unless timely checked), I suspect that matter possessing very different properties may sooner or later be produced; and although it may have passed that stage wherein the specific properties of the matter secreted are no longer present in it, yet when applied to a sore (as in the casual way) it might dispose that sore to ulcerate, and from its irritation the system would probably become affected; and thus, by assuming some of its strongest characters, it would imitate the genuine cow-pox. From the preceding observations on the matter of smallpox when decomposed it must, I conceive, be admitted that cow-pox matter in the state now described may produce a disease, the effects of which may be felt both locally and generally, yet that the disease thus induced may not be effectual in obviating the future effects of variolous contagion. In the case of Mary Miller, related by Mr. Kite in the volume above alluded to, it appears that the inflammation and suppuration of the inoculated arm were more than usually severe, although the system underwent no specific change from the action of the virus; which appears from the patient's sickening seven weeks afterwards with the natural smallpox, which went through its course. Some of the cases communicated by Mr. Earle tend further to confirm this fact, as the matter there manifestly produced ulceration on the inoculated part to a considerable extent. Fourthly. Whether the cow-pox is a spontaneous disease in the cow, or is to be attributed to matter conveyed to the animal, as I have conceived, from the horse, is a question which, though I shall not attempt now fully to discuss, yet I shall digress so far as to adduce some further observations, and to give my reasons more at large for taking up an opinion that to some had appeared fanciful. The aggregate of these observations, though not amounting to positive proof, forms presumptive evidence of so forcible a kind that I imagine it might, on any other person, have made the same impression it did on me, without fixing the imputation of credulity. First: I conceived this was the source, from observing that where the cow-pox had appeared among the dairies here (unless it could be traced to the introduction of an infected cow or servant) it had been preceded at the farm by a horse diseased in the manner already described, which horse had been attended by some of the milkers. Secondly: From its being a popular opinion throughout this great dairy country, and from its being insisted on by those who here attend sick cattle. Thirdly: From the total absence of the disease in Ireland and Scotland, where the men-servants are not employed in the dairies. [Footnote: This information was communicated to me from the first authority.] Fourthly: From having observed that morbid matter generated by the horse frequently communicates, in a casual way, a disease to the human subject so like the cow-pox that, in many cases, it would be difficult to make the distinction between one and the other. [Footnote: The sound skin does not appear to be susceptible of this virus when inserted into it, but, when previously diseased from little accidents, its effects are often conspicuous.] Fifthly: From being induced to suppose, from experiments, that some of those who had been thus affected from the horse resisted the smallpox. Sixthly: From the progress and general appearance of the pustule on the arm of the boy whom I inoculated with matter taken from the hand of a man infected by a horse; and from the similarity to the cow-pox of general constitutional symptoms which followed. [Footnote: This case (on which I laid no inconsiderable stress in my late treatise, as presumptive evidence of the fact adduced) seems to have been either mistaken or overlooked by those who have commented upon it. (See Case XVIII, p. 36.) The boy, unfortunately, died of a fever at a parish workhouse before I had an opportunity of observing what effects would have been produced by the matter of smallpox.] I fear it would be trespassing too far to adduce the general testimony of our farmers in support of this opinion; yet I beg leave to introduce an extract of a letter on this subject from the Rev. Mr. Moore, of Chalford Hill, in this county: "In the month of November, 1797, my horse had diseased heels, which was certainly what is termed the grease; and at a short subsequent period my cow was also affected with what a neighbouring farmer (who was conversant with the complaints of cattle) pronounced to be the cow-pox, which he at the same time observed my servant would be infected with: and this proved to be the case; for he had eruptions on his hands, face, and many, parts of the body, the pustules appearing large, and not much like the smallpox, for which he had been inoculated a year and a half before, and had then a very heavy burthen. The pustules on the face might arise from contact with his hands, as he had a habit of rubbing his forehead, where the sores were the largest and the thickest. "The boy associated with the farmer's sons during the continuance of the disease, neither of whom had had the smallpox, but they felt no ill effects whatever. He was not much indisposed, as the disease did not prevent him from following his occupations as usual. No other person attended the horse or milked the cow but the lad above mentioned. I am firmly of opinion that the disease in the heels of the horse, which was a virulent grease, was the origin of the servant's and the cow's malady." But to return to the more immediate object of this proposition. From the similarity of symptoms, both constitutional and local, between the cow-pox and the disease received from morbid matter generated by a horse, the common people in this neighbourhood, when infected with this disease, through a strange perversion of terms, frequently call it the cow-pox. Let us suppose, then, such a malady to appear among some of the servants at a farm, and at the same time that the cow-pox were to break out among the cattle; and let us suppose, too, that some of the servants were infected in this way, and that others received the infection from the cows. It would be recorded at the farm, and among the servants themselves wherever they might afterwards be dispersed, that they had all had the cow-pox. But it is clear that an individual thus infected from the horse would neither be for a certainty secure himself, nor would he impart security to others were they inoculated by virus thus generated. He still would be in danger of taking the smallpox. Yet were this to happen before the nature of the cowpox be more maturely considered by the public my evidence on the subject might be depreciated unjustly. For an exemplification of what is here advanced relative to the nature of the infection when received directly from the horse see Inquiry into the Causes and Effects of the Variolae Vaccinae, pp. 27, 28, 29, 30, and p. 35; and by way of further example, I beg leave to subjoin the following intelligence received from Mr. Fewster, Surgeon, of Thornbury, in this county, a gentleman perfectly well acquainted with the appearances of the cow-pox on the human subject: "William Morris, aged thirty-two, servant to Mr. Cox of Almondsbury, in this county, applied to me the 2d of April, 1798. He told me that, four days before, be found a stiffness and swelling in both his hands, which were so painful it was with difficulty he continued his work; that he had been seized with pain in his head, small of the back, and limbs, and with frequent chilly fits succeeded by fever. On examination I found him still affected with these symptoms, and that there was a great prostration of strength. Many parts of his hands on the inside were chapped, and on the middle joint of the thumb of the right hand there was a small phagedenic ulcer, about the size of a large pea, discharging an ichorous fluid. On the middle finger of the same hand there was another ulcer of a similar kind. These sores were of a CIRCULAR form, and he described their first appearance as being somewhat like blisters arising from a burn. He complained of excessive pain, which extended up his arm into the axilla. These symptoms and appearances of the sores were so exactly like the cow-pox that I pronounced he had taken the distemper from milking cows. He assured me he had not milked a cow for more than half a year, and that his master's cows had nothing the matter with them. I then asked him if his master had a GREASY horse, which he answered in the affirmative, and further said that he had constantly dressed him twice a day for the [Footnote: HC--Vol.88] last three weeks or more, and remarked that the smell of his hands was much like that of the horses's heels. On the 5th of April I again saw him, and found him still complaining of pain in both hands, nor were his febrile symptoms at all relieved. The ulcers had now spread to the size of a seven-shilling gold coin, and another ulcer, which I had not noticed before, appeared on the first joint of the forefinger of the left hand, equally painful with that on the right. I ordered him to bathe his hands in warm bran and water, applied escharotics to the ulcers, and wrapped his hands up in a soft cataplasm. The next day he was much relieved, and in something more than a fortnight got well. He lost his nails from the thumb and fingers that were ulcerated." The sudden disappearance of the symptoms in this case after the application of the escharotics to the sores is worthy of observation; it seems to show that they were kept up by the irritation of the ulcers. The general symptoms which I have already described of the cow- pox, when communicated in a casual way to any great extent, will, I am convinced, from the many cases I have seen, be found accurate; but from the very slight indisposition which ensues in cases of inoculation, where the pustule, after affecting the constitution, quickly runs into a scab spontaneously, or is artificially suppressed by some proper application, I am induced to believe that the violence of the symptoms may be ascribed to the inflammation and irritation of the ulcers (when ulceration takes place to any extent, as in the casual cow-pox), and that the constitutional symptoms which appear during the presence of the sore, while it assumes the character of a pustule only, are felt but in a very trifling degree. This mild affection of the system happens when the disease makes but a slight local impression on those who have been accidentally infected by cows; and, as far as I have seen, it has uniformly happened among those who have been inoculated, when a pustule only and no great degree of inflammation or any ulceration has taken place from the inoculation. The following cases will strengthen this opinion. The cow-pox appeared at a farm in the village of Stonehouse, in this county, about Michaelmas last, and continued gradually to pass from one cow to another till the end of November, On the twenty-sixth of that month some ichorous matter was taken from a cow and dried upon a quill. On the 2d of December some of it was inserted into a scratch, made so superficial that no blood appeared, on the arms of Susan Phipps, a child seven years old. The common inflammatory appearances took place in consequence, and advanced till the fifth day, when they had so much subsided that I did not conceive any thing further would ensue. 6th: Appearances stationary. 7th: The inflammation began to advance. 8th: A vesication, perceptible on the edges, forming, as in the inoculated smallpox, an appearance not unlike a grain of wheat, with the cleft, or indentation in the centre. 9th: Pain in the axilla. 10th: A little headache; pulse, 110; tongue not discoloured; countenance in health. 11th, 12th: No perceptible illness; pulse about 100. 13th: The pustule was now surrounded by an efflorescence, interspersed with very minute confluent pustules to the extent of about an inch. Some of these pustules advanced in size and maturated. So exact was the resemblance of the arm at this stage to the general appearance of the inoculated smallpox that Mr. D., a neighbouring surgeon, who took some matter from it, and who had never seen the cow-pox before, declared he could not perceive any difference. [Footnote: That the cow-pox was a supposed guardian of the constitution from the action of the smallpox has been a prevalent idea for a long time past; but the similarity in the constitutional effects between one disease and the other could never have been so accurately observed had not the inoculation of the cow-pox placed it in a new and stronger point of view. This practice, too, has shewn us, what before lay concealed, the rise and progress of the pustule formed by the insertion of the virus, which places in a most conspicuous light its striking resemblance to the pustule formed from the inoculated smallpox.] The child's arm now shewed a disposition to scab, and remained nearly stationary for two or three days, when it began to run into an ulcerous state, and THEN commenced a febrile indisposition accompanied with an increase of axillary tumour. The ulcer continued spreading near a week, during which time the child continued ill, when it increased to a size nearly as large as a shilling. It began now to discharge pus; granulations sprang up, and it healed. This child had before been of a remarkably sickly constitution, but is now in very high health. Mary Hearn, twelve years of age, was inoculated with matter taken from the arm of Susan Phipps. 6th day: A pustule beginning to appear, slight pain in the axilla. 7th: A distinct vesicle formed. 8th: The vesicle increasing; edges very red; no deviation in its appearance at this time from the inoculated smallpox. 9th: No indisposition; pustule advancing. 10th: The patient felt this evening a slight febrile attack. 11th: Free from indisposition. 12th, 13th: The same. 14th: An efflorescence of a faint red colour extending several inches round the arm. The pustule, beginning to shew a disposition to spread, was dressed with an ointment composed of hydrarg. nit. rub. and ung. cerce. The efflorescence itself was covered with a plaster of ung. hydr. fort. In six hours it was examined, when it was found that the efflorescence had totally disappeared. The application of the ointment with the hydr. nit. rub. was made use of for three days, when, the state of the pustule remaining stationary, it was exchanged for the ung. hydr. nit. This appeared to have a more active effect than the former, and in two or three days the virus seemed to be subdued, when a simple dressing was made use of; but the sore again shewing a disposition to inflame, the ung. hydr. nit. was again applied, and soon answered the intended purpose effectually. The girl, after the tenth day, when, as has been observed, she became a little ill, shewed not the least symptom of indisposition. She was afterwards exposed to the action of variolous; matter, and completely resisted it. Susan Phipps also went through a similar trial. Conceiving these cases to be important, I have given them in detail: first, to urge the precaution of using such means as may stop the progress of the pustule; and, secondly, to point out (what appears to be the fact) that the most material indisposition, or at least that which is felt most sensibly, DOES NOT ARISE PRIMARILY FROM THE FIRST ACTION OF THE VIRUS ON THE CONSTITUTION, BUT THAT IT OFTEN COMES ON, IF THE PUSTULE IS LEFT TO CHANCE, AS A SECONDARY DISEASE. This leads me to conjecture, what experiment must finally determine, that they who have had the smallpox are not afterwards susceptible of the primary action of the cow-pox virus; for seeing that the simple virus itself, when it has not passed beyond the boundary of a vesicle, excites in the system so little commotion, is it not probable the trifling illness, thus induced may be lost in that which so quickly, and oftentimes so severely, follows in the casual cow- pox from the presence of corroding ulcers? This consideration induces me to suppose that I may have been mistaken in my former observation on this subject. In this respect, as well as many others, a parallel may be drawn between this disease and the smallpox. In the latter, the patient first feels the effect of what is called the absorption of the virus. The symptoms then often nearly retire, when a fresh attack commences, different from the first, and the illness keeps pace with the progress of the pustules through their different stages of maturation, ulceration, etc. Although the application I have mentioned in the case of Mary Hearn proved sufficient to check the progress of ulceration and prevent any secondary symptoms, yet, after the pustule has duly exerted its influence, I should prefer the destroying it quickly and effectually to any other mode. The term caustic to a tender ear (and I conceive none feel more interested in this inquiry than the anxious guardians of a nursery) may sound harsh and unpleasing, but every solicitude that may arise on this account will no longer exist when it is understood that the pustule, in a state fit to be acted upon, is then quite superficial, and that it does not occupy the space of a silver penny. [Footnote: I mention escharotics for stopping the progress of the pustule because I am acquainted with their efficacy; probably more simple means might answer the purpose quite as well, such as might be found among the mineral and vegetable astringents.] As a proof of the efficacy of this practice, even before the virus has fully exerted itself on the system, I shall lay before my reader the following history: By a reference to the treatise on the Variolae Vaccinae it will be seen that, in the month of April, 1798, four children were inoculated with the matter of cow-pox, and that in two of these cases the virus on the arm was destroyed soon after it had produced a perceptible sickening. Mary James, aged seven years, one of the children alluded to, was inoculated in the month of December following with fresh variolous matter, and at the same time was exposed to the effluvia of a patient affected with the smallpox. The appearance and progress of the infected arm was, in every respect similar to that which we generally observe when variolous matter has been inserted into the skin of a person who has not previously undergone either the cow-pox or the smallpox. On the eighth day, conceiving there was infection in it, she was removed from her residence among those who had not had the smallpox. I was now anxiously waiting the result, conceiving, from the state of the girl's arm, she would fall sick about this time. On visiting her on the evening of the following day (the ninth) all I could learn from the woman who attended her was that she felt somewhat hotter than usual during the night, but was not restless; and that in the morning there was the faint appearance of a rash about her wrists. This went off in a few hours, and was not at all perceptible to me on my visit in the evening. Not a single eruption appeared, the skin having been repeatedly and carefully examined. The inoculated arm continued to make the usual progress to the end, through all the stages of inflammation, maturation, and scabbing. On the eighth day matter was taken from the arm of this girl (Mary James) and inserted into the arms of her mother and brother (neither of whom had had either the smallpox or the cow-pox), the former about fifty years of age, the latter six. On the eighth day after the insertion the boy felt indisposed, and continued unwell two days, when a measles-like rash appeared on his hands and wrists, and was thinly scattered over his arms. The day following his body was marbled over with an appearance somewhat similar, but he did not complain, nor did he appear indisposed. A few pustules now appeared, the greater part of which went away without maturating. On the ninth day the mother began to complain. She was a little chilly and had a headache for two days, but NO PUSTULE APPEARED on the skin, nor had she any appearance of a rash. The family was attended by an elderly woman as a nurse, who in her infancy had been exposed to the contagion of the smallpox, but had resisted it. This woman was now infected, but had the disease in the slightest manner, a very few eruptions appearing, two or three of which only maturated. From a solitary instance like that adduced of Mary James, whose constitution appears to have resisted the action of the variolous virus, after the influence of the cow-pox virus had been so soon arrested in its progress, no positive conclusion can be fairly drawn; nor from the history of the three other patients who were subsequently infected, but, nevertheless, the facts collectively may be deemed interesting. That one mild variety of the smallpox has appeared I have already plainly shewn; [Footnote: See Inquiry into the Causes and Effects of the Variolae Vaccinae, p. 54 (of original article)], and by the means now mentioned we probably have it in our power to produce at will another. At the time when the pustule was destroyed in the arm of Mary James I was informed she had been indisposed about twelve hours; but I am now assured by those who were with her that the space of time was much less. Be that as it may, in cases of cow-pox inoculation I would not recommend any application to subdue the action of the pustule until convincing proofs had appeared of the patient's having felt its effects at least twelve hours. No harm, indeed, could ensue were a longer period to elapse before the application was made use of. In short, it should be suffered to have as full an effect as it could, consistently with the state of the arm. As the cases of inoculation multiply, I am more and more convinced of the extreme mildness of the symptoms arising merely from the primary action of the virus on the constitution, and that those symptoms which, as in the accidental cow-pox, affect the patient with severity, are entirely secondary, excited by the irritating processes of inflammation and ulceration; and it appears to me that this singular virus possesses an irritating quality of a peculiar kind, but as a single cow-pox pustule is all that is necessary to render the variolous virus ineffectual, and as we possess the means of allaying the irritation, should any arise, it becomes of little or no consequence. It appears then, as far as an inference can be drawn from the present progress of cow-pox inoculation, that it is an accidental circumstance only which can render this a violent disease, and a circumstance of that nature which, fortunately, it is in the power of almost every one to avoid. I allude to the communication of the disease from cows. In this case, should the hands of the milker be affected with little accidental sores to any extent, every sore would become the nidus of infection and feel the influence of the virus; and the degree of violence in the constitutional symptoms would be in proportion to the number and to the state of these local affections. Hence it follows that a person, either by accident or design, might be so filled with these wounds from contact with the virus that the constitution might sink under the pressure. Seeing that we possess the means of rendering the action of the sores mild, which, when left to chance, are capable of producing violent effects; and seeing, too, that these sores bear a resemblance to the smallpox, especially the confluent, should it not encourage the hope that some topical application might be used with advantage to counteract the fatal tendency of that disease, when it appears in this terrific form? At what stage or stages of the disease this may be done with the most promising expectation of success I will not pretend now to determine. I only throw out this idea as the basis of further reasoning and experiment. I have often been foiled in my endeavours to communicate the cow- pox by inoculation. An inflammation will sometimes succeed the scratch or puncture, and in a few days disappear without producing any further effect. Sometimes it will even produce an ichorous fluid, and yet the system will not be affected. The same thing we know happens with the smallpox virus. Four or five servants were inoculated at a farm contiguous to this place, last summer, with matter just taken from an infected cow. A little inflammation appeared on all their arms, but died away without producing a pustule; yet all these servants caught the disease within a month afterwards from milking the infected cows, and some of them had it severely. At present no other mode than that commonly practiced for inoculating the smallpox has been used for giving the cow-pox; but it is probable this might be varied with advantage. We should imitate the casual communication more clearly were we first, by making the smallest superficial incision or puncture on the skin, to produce a little scab, and then, removing it, to touch the abraded part with the virus. A small portion of a thread imbrued in the virus (as in the old method of inoculating the smallpox) and laid upon the slightly incised skin might probably prove a successful way of giving the disease; or the cutis might be exposed in a minute point by an atom of blistering plaster, and the virus brought in contact with it. In the cases just alluded to, where I did not succeed in giving the disease constitutionally, the experiment was made with matter taken in a purulent state from a pustule on the nipple of a cow. Is PURE PUS, though contained in a smallpox pustule, ever capable of producing the smallpox perfectly? I suspect it is not. Let us consider that it is always preceded by the limpid fluid, which, in constitutions susceptible of variolous contagion, is always infectious; and though, on opening a pustule, its contents may appear perfectly purulent, yet a given quantity of the limpid fluid may, at the same time, be blended with it, though it would be imperceptible to the only test of our senses, the eye. The presence, then, of this fluid, or its mechanical diffusion through pus, may at all times render active what is apparently MERE PUS, while its total absence (as in stale pustules) may be attended with the imperfect effects we have seen. It would be digressing too widely to go far into the doctrine of secretion, but as it will not be quite extraneous, I shall just observe that I consider both the pus and the limpid fluid of the pustule as secretions, but that the organs established by nature to perform the office of secreting these fluids may differ essentially in their mechanical structure. What but a difference in the organization of glandular bodies constitutes the difference in the qualities of the fluids secreted? From some peculiar derangement in the structure or, in other words, some deviation in the natural action of a gland destined to create a mild, innoxious fluid, a poison of the most deadly nature may be created; for example: That gland, which in its sound state secretes pure saliva, may, from being thrown into diseased action, produce a poison of the most destructive quality. Nature appears to have no more difficulty in forming minute glands among the vascular parts of the body than she has in forming blood vessels, and millions of these can be called into existence, when inflammation is excited, in a few hours. [Footnote: Mr. Home, in his excellent dissertation on pus and mucus, justifies this assertion.] In the present early stage of the inquiry (for early it certainly must be deemed), before we know for an absolute certainty how soon the virus of the cow-pox may suffer a change in its specific properties, after it has quitted the limpid state it possesses when farming a pustule, it would be prudent for those who have been inoculated with it to submit to variolous inoculation. No injury or inconvenience can accrue from this; and were the same method practiced among those who, from inoculation, have felt the smallpox in an unsatisfactory manner at any period of their lives, it might appear that I had not been too officious in offering a cautionary, hint in recommending a second inoculation with matter in its most perfect state. And here let me suppose, for argument's sake (not from conviction), that one person in an hundred after having had the cow-pox should be found susceptible of the smallpox, would this invalidate the utility of the practice? For, waiving all other considerations, who will deny that the inoculated smallpox, although abstractedly it may be considered as harmless, does not involve in itself something that in numberless instances proves baneful to the human frame. That in delicate constitutions it sometimes excites scrofula is a fact that must generally be subscribed to, as it is so obvious to common observation. This consideration is important. As the effects of the smallpox inoculation on those who have had the cow-pox will be watched with the most scrupulous eye by those who prosecute this inquiry, it may be proper to bring to their recollection some facts relative to the smallpox, which I must consider here as of consequence, but which hitherto seem not to have made a due impression. It should be remembered that the constitution cannot, by previous infection, be rendered totally unsusceptible of the variolous poison; neither the casual nor the inoculated smallpox, whether it produces the disease in a mild or in a violent way, can perfectly extinguish the susceptibility. The skin, we know, is ever ready to exhibit, though often in a very limited degree, the effects of the poison when inserted there; and how frequently do we see, among nurses, when much exposed to the contagion, eruptions, and these sometimes preceded by sensible illness! yet should any thing like an eruption appear, or the smallest degree of indisposition, upon the insertion of the variolous matter on those who have gone through the cow-pox, my assertions respecting the peculiarities of the disease might be unjustly discredited. I know a gentleman who, many years ago, was inoculated for the smallpox, but having no pustules, or scarcely any constitutional affection that was perceptible, he was dissatisfied, and has since been repeatedly inoculated. A vesicle has always been produced in the arm in consequence, with axillary swelling and a slight indisposition; this is by no means a rare occurrence. It is probable that fluid thus excited upon the skin would always produce the smallpox. On the arm of a person who had gone through the cow-pox many years before I once produced a vesication by the insertion of variolous matter, and, with a little of the fluid, inoculated a young woman who had a mild, but very efficacious, smallpox in consequence, although no constitutional effect was produced on the patient from whom the matter was taken. The following communication from Mr. Fewster affords a still clearer elucidation of this fact. Mr. Fewster says: "On the 3d of April, 1797, I inoculated Master H--, aged fourteen months, for the smallpox. At the usual time he sickened, had a plentiful eruption, particularly on his face, and got well. His nursemaid, aged twenty-four, had many years before gone through the smallpox, in the natural way, which was evident from her being much pitted with it. She had used the child to sleep on her left arm, with her left cheek in contact with his face, and during his inoculation he had mostly slept in that manner. About a week after the child got well she (the nurse) desired me to look at her face, which she said was very painful. There was a plentiful eruption on the left cheek, BUT NOT ON ANY OTHER PART OF THE BODY, which went on to maturation. "On enquiry I found that three days before the appearance of the eruption she was taken with slight chilly fits, pain in her head and limbs, and some fever. On the appearance of the eruption these pains went off, and now, the second day of the eruption, she complains of a little sore throat. Whether the above symptoms are the effects of the smallpox or a recent cold I do not know. On the fifth day of the eruption I charged a lancet from two of the pustules, and on the next day I inoculated two children, one two years, the other four months old, with the matter. At the same time I inoculated the mother and eldest sister with variolous matter taken from Master H--. On the fifth day of their inoculation ALL their arms were inflamed alike; and on the eighth day the eldest of those inoculated from the nurse sickened, and the youngest on the eleventh. They had both a plentiful eruption, from which I inoculated several others, who had the disease very favourably. The mother and the other child sickened about the same time, and likewise had a plentiful eruption. "Soon after, a man in the village sickened with the smallpox and had a confluent kind. To be convinced that the children had had the disease effectually I took them to his house and inoculated them in both arms with matter taken from him, but without effect." These are not brought forward as uncommon occurrences, but as exemplifications of the human system's susceptibility of the variolous contagion, although it has been previously sensible of its action. Happy is it for mankind that the appearance of the small-pox a second time on the same person, beyond a trivial extent, is so extremely rare that it is looked upon as a phaenomenon! Indeed, since the publication of Dr. Heberden's paper on the Varicellae, or chicken-pox, the idea of such an occurrence, in deference to authority so truly respectable, has been generally relinquished. This I conceive has been without just reason; for after we have seen, among many others, so strong a case as that recorded by Mr. Edward Withers, Surgeon, of Newbury, Berks, in the fourth volume of the Memoirs of the Medical Society of London (from which I take the following extracts), no one, I think, will again doubt the fact. "Mr. Richard Langford, a farmer of West Shefford, in this county (Berks), about fifty years of age, when about a month old had the smallpox at a time when three others of the family had the same disease, one of whom, a servant man, died of it. Mr. Langford's countenance was strongly indicative of the malignity of the distemper, his face being so remarkably pitted and seamed as to attract the notice of all who saw him, so that no one could entertain a doubt of his having had that disease in a most inveterate manner." Mr. Withers proceeds to state that Mr. Langford was seized a second time, had a bad confluent smallpox, and died on the twenty-first day from the seizure; and that four of the family, as also a sister of the patient's, to whom the disease was conveyed by her son's visiting his uncle, falling down with the smallpox, fully satisfied the country with regard to the nature of the disease, which nothing short of this would have done; the sister died. "This case was thought so extraordinary a one as to induce the rector of the parish to record the particulars in the parish register." It is singular that in most cases of this kind the disease in the first instance has been confluent; so that the extent of the ulceration on the skin (as in the cow-pox) is not the process in nature which affords security to the constitution. As the subject of the smallpox is so interwoven with that which is the more immediate object of my present concern, it must plead my excuse for so often introducing it. At present it must be considered is a distemper not well understood. The inquiry I have instituted into the nature of the cow-pox will probably promote its more perfect investigation. The inquiry of Dr. Pearson into the history of the cow-pox having produced so great a number of attestations in favour of my assertion that it proves a protection to the human body from the smallpox, I have not been assiduous in seeking for more; but as some of my friends have been so good as to communicate the following, I shall conclude these observations with their insertion. Extract of a letter from Mr. Drake, Surgeon, at Stroud, in this county, and late Surgeon to the North Gloucester Regiment of Militia: "In the spring of the year 1796 I inoculated men, women, and children to the amount of about seventy. Many of the men did not receive the infection, although inoculated at least three times and kept in the same room with those who actually underwent the disease during the whole time occupied by them in passing through it. Being anxious they should, in future, be secure against it, I was very particular in my inquiries to find out whether they ever had previously had it, or at any time been in the neighbourhood of people labouring under it. But, after all, the only satisfactory information I could obtain was that they had had the cow-pox. As I was then ignorant of such a disease affecting the human subject, I flattered myself what they imagined to be the cow-pox was in reality the smallpox in a very slight degree. I mentioned the circumstance in the presence of the officers, at the time expressing my doubts if it were not smallpox, and was not a little surprised when I was told by the Colonel that he had frequently heard you mention the cow-pox as a disease endemial to Gloucestershire, and that if a person were ever affected by it, you supposed him afterwards secure from the smallpox. This excited my curiosity, and when I visited Gloucestershire I was very inquisitive concerning the subject, and from the information I have since received, both from your publication and from conversation with medical men of the greatest accuracy in their observations, I am fully convinced that what the men supposed to be cow-pox was actually so, and I can safely affirm that they effectually resisted the smallpox." Mr. Fry, Surgeon, at Dursley in this county, favours me with the following communication: "During the spring of the year 1797 I inoculated fourteen hundred and seventy-five patients, of all ages, from a fortnight old to seventy years; amongst whom there were many who had previously gone through the cow-pox. The exact number I cannot state; but if I say there were nearly thirty, I am certainly within the number. There was not a single instance of the variolous matter producing any constitutional effect on these people, nor any greater degree of local inflammation than it would have done in the arm of a person who had before gone through the smallpox, notwithstanding it was invariably inserted four, five, and sometimes six different times, to satisfy the minds of the patients. In the common course of inoculation previous to the general one scarcely a year passed without my meeting with one or two instances of persons who had gone through the cow-pox, resisting the action of the variolous contagion. I may fairly say that the number of people I have seen inoculated with the smallpox who, at former periods, had gone through the cow-pox, are not less than forty; and in no one instance have I known a patient receive the smallpox, notwithstanding they invariably continued to associate with other inoculated patients during the progress of the disease, and many of them purposely exposed themselves to the contagion of the natural smallpox; whence I am fully convinced that a person who had fairly had the cow-pox is no longer capable of being acted upon by the variolous matter. "I also inoculated a very considerable number of those who had had a disease which ran through the neighbourhood a few years ago, and was called by the common people the swine-pox, not one of whom received the smallpox. [Footnote: This was that mild variety of the smallpox which I have noticed in the late Treatise on the Cow-Pox (p. 233).] "There were about half a dozen instances of people who never had either the cow-or swine-pox, yet did not receive the smallpox, the system not being in the least deranged, or the arms inflamed, although they were repeatedly inoculated, and associated with others who were labouring under the disease; one of them was the son of a farrier." Mr. Tierny, Assistant Surgeon of the South Gloucester Regiment of Militia, has obliged me with the following information: "That in the summer of the year of 1798 he inoculated a great number of the men belonging to the regiment, and that among them he found eleven who, from having lived in dairies, had gone through the cow-pox. That all of them resisted the smallpox except one, but that on making the most rigid and scrupulous enquiry at the farm in Gloucestershire, where the man said he lived when he had the disease, and among those with whom, at the same time, he declared he had associated, and particularly of a person in the parish, whom he said had dressed his fingers, it most clearly appeared that he aimed at an imposition, and that he never had been affected with the cow-pox." [Footnote: The public cannot be too much upon their guard respecting persons of this description.] Mr. Tierny remarks that the arms of many who were inoculated after having had the cow-pox inflamed very quickly, and that in several a little ichorous fluid was formed. Mr. Cline, who in July last was so obliging at my request as to try the efficacy of the cow-pox virus, was kind enough to give me a letter on the result of it, from which the following is an extract: "My DEAR SIR: "The cow-pox experiment has succeeded admirably. The child sickened on the seventh day, and the fever, which was moderate, subsided on the eleventh. The inflammation arising from the insertion of the virus extended to about four inches in diameter, and then gradually subsided, without having been attended with pain or other inconvenience. There were no eruptions. "I have since inoculated him with smallpox matter in three places, which were slightly inflamed on the third day, and then subsided. "Dr. Lister, who was formerly physician to the Smallpox Hospital, attended the child with me, and he is convinced that it is not possible to give him the smallpox. I think the substituting the cow-pox poison for the smallpox promises to be one of the greatest improvements that has ever been made in medicine; and the more I think on the subject, the more I am impressed with its importance. "With great esteem "I am, etc., "HENRY CLINE. "Lincoln's Inn Fields, August 2, 1798." From communications, with which I have been favoured from Dr. Pearson, who has occasionally reported to me the result of his private practice with the vaccine virus in London, and from Dr. Woodville, who also has favoured me with an account of his more extensive inoculation with the same virus at the Smallpox Hospital, it appears that many of their patients have been affected with eruptions, and that these eruptions have maturated in a manner very similar to the variolous. The matter they made use of was taken in the first instance from a cow belonging to one of the great milk farms in London. Having never seen maturated pustules produced either in my own practice among those who were casually infected by cows, or those to whom the disease had been communicated by inoculation, I was desirous of seeing the effect of the matter generated in London, on subjects living in the country. A thread imbrued in some of this matter was sent to me, and with it two children were inoculated, whose cases I shall transcribe from my notes. Stephen Jenner, three years and a half old. 3d day: The arm shewed a proper and decisive inflammation. 6th: A vesicle arising. 7th: The pustule of a cherry colour. 8th: Increasing in elevation. A few spots now appear on each arm near the insertion of the inferior tendons of the biceps muscles. They are very small and of a vivid red colour. The pulse natural; tongue of its natural hue; no loss of appetite or any symptom of indisposition. 9th: The inoculated pustule on the arm this evening began to inflame, and gave the child uneasiness; he cried and pointed to the seat of it, and was immediately afterwards affected with febrile symptoms. At the expiration of two hours after the seizure a plaster of ung. hydrarg. fort, was applied, and its effect was very quickly perceptible, for in ten minutes he resumed his usual looks and playfulness. On examining the arm about three hours after the application of the plaster its effects in subduing the inflammation were very manifest. 10th: The spots on the arms have disappeared, but there are three visible in the face. 11th: Two spots on the face are gone; the other barely perceptible. 13th: The pustule delineated in the second plate in the Treatise on the Variolae Vaccinae is a correct representation of that on the child's arm as it appears at this time. 14th: Two fresh spots appear on the face. The pustule on the arm nearly converted into a scab. As long as any fluid remained in it it was limpid. James Hill, four years old, was inoculated on the same day, and with part of the same matter which infected Stephen Jenner. It did not appear to have taken effect till the fifth day. 7th: A perceptible vesicle: this evening the patient became a little chilly; no pain or tumour discoverable in the axilla. 8th: Perfectly well. 9th: The same. 10th: The vesicle more elevated than I have been accustomed to see it, and assuming more perfectly the variolous character than is common with the cow-pox at this stage. 11th: Surrounded by an inflammatory redness, about the size of a shilling, studded over with minute vesicles. The pustule contained a limpid fluid till the fourteenth day, after which it was incrusted over in the usual manner; but this incrustation or scab being accidentally rubbed off, it was slow in healing. These children were afterwards fully exposed to the smallpox contagion without effect. Having been requested by my friend, Mr. Henry Hicks, of Eastington, in this county, to inoculate two of his children, and at the same time some of his servants and the people employed in his manufactory, matter was taken from the arm of this boy for the purpose. The numbers inoculated were eighteen. They all took the infection, and either on the fifth or sixth day a vesicle was perceptible on the punctured part. Some of them began to feel a little unwell on the eighth day, but the greater number on the ninth. Their illness, as in the former cases described, was of short duration, and not sufficient to interrupt, but at very short intervals, the children from their amusements, or the servants and manufacturers from following their ordinary business. Three of the children whose employment in the manufactory was in some degree laborious had an inflammation on their arms beyond the common boundary about the eleventh or twelfth day, when the feverish symptoms, which before were nearly gone off, again returned, accompanied with increase of axillary tumour. In these cases (clearly perceiving that the symptoms were governed by the state of the arms) I applied on the inoculated pustules, and renewed the application three or four times within an hour, a pledget of lint, previously soaked in aqua lythargyri acetati [Footnote: Goulard's extract of Saturn.] and covered the hot efflorescence surrounding them with cloths dipped in cold water. The next day I found this simple mode of treatment had succeeded perfectly. The inflammation was nearly gone off, and with it the symptoms which it had produced. Some of these patients have since been inoculated with variolous matter, without any effect beyond a little inflammation on the part where it was inserted. Why the arms of those inoculated with the vaccine matter in the country should be more disposed to inflame than those inoculated in London it may be difficult to determine. From comparing my own cases with some transmitted to me by Dr. Pearson and Dr. Woodville, this appears to be the fact; and what strikes me as still more extraordinary with respect to those inoculated in London is the appearance of maturating eruptions, In the two instances only which I have mentioned (the one from the inoculated, the other from the casual, cow-pox) a few red spots appeared, which quickly went off without maturating. The case of the Rev. Mr. Moore's servant may, indeed, seem like a deviation from the common appearances in the country, but the nature of these eruptions was not ascertained beyond their not possessing the property of communicating the disease by their effluvia. Perhaps the difference we perceive may be owing to some variety in the mode of action of the virus upon the skin of those who breathe the air of London and those who live in the country. That the erysipelas assumes a different form in London from what we see it put on in this country is a fact very generally acknowledged. In calling the inflammation that is excited by the cow-pox virus erysipelatous, perhaps I may not be critically exact, but it certainly approaches near to it. Now, as the diseased action going forward in the part infected with the virus may undergo different modifications according to the peculiarities of the constitution on which it is to produce its effect, may it not account for the variation which has been observed? To this it may probably be objected that some of the patients inoculated, and who had pustules in consequence, were newly come from the country; but I conceive that the changes wrought in the human body through the medium of the lungs may be extremely rapid. Yet, after all, further experiments made in London with vaccine virus generated in the country must finally throw a light on what now certainly appears obscure and mysterious. The principal variation perceptible to me in the action of the vaccine virus generated in London from that produced in the country was its proving more certainly infectious and giving a less disposition in the arm to inflame. There appears also a greater elevation of the pustule above the surrounding skin. In my former cases the pustule produced by the insertion of the virus was more like one of those which are so thickly spread over the body in a bad kind of confluent smallpox. This was more like a pustule of the distinct smallpox, except that I saw no instance of pus being formed in it, the matter remaining limpid till the period of scabbing. Wishing to see the effects of the disease on an infant newly born, my nephew, Mr. Henry Jenner, at my request, inserted the vaccine virus into the arm of a child about twenty hours old. His report to me is that the child went through the disease without apparent illness, yet that it was found effectually to resist the action of variolous matter with which it was subsequently inoculated. I have had an opportunity of trying the effects of the cow-pox matter on a boy, who, the day preceding its insertion, sickened with the measles. The eruption of the measles, attended with cough, a little pain in the chest; and the usual symptoms accompanying the disease, appeared on the third day and spread all over him. The disease went through its course without any deviation from its usual habits; and, notwithstanding this, the cow-pox virus excited its common appearances, both on the arm and on the constitution, without any febrile interruption; on the sixth day there was a vesicle. 8th: Pain in the axilla, chilly, and affected with headache. 9th: Nearly well. 12th: The pustule spread to the size of a large split-pea, but without any surrounding efflorescence. It soon afterwards scabbed, and the boy recovered his general health rapidly. But it should be observed that before it scabbed the efflorescence which had suffered a temporary suspension advanced in the usual manner. Here we see a deflation from the ordinary habits of the smallpox, as it has been observed that the presence of the measles suspends the action of the variolous matter. The very general investigation that is now taking place, chiefly through inoculation (and I again repeat my earnest hope that it may be conducted with that calmness and moderation which should ever accompany a philosophical research), must soon place the vaccine disease in its just point of view. The result of all my trials with the virus on the human subject has been uniform. In every instance the patient who has felt its influence, has completely lost the susceptibility for the variolous contagion; and as these instances are now become numerous, I conceive that, joined to the observations in the former part of this paper, they sufficiently preclude me from the necessity of entering into controversies with those who have circulated reports adverse to my assertions, on no other evidence than what has been casually collected. III A CONTINUATION OF FACTS AND OBSERVATIONS RELATIVE TO THE VARIOUS VACCINES, OR COW-POX. 1800 Since my former publications on the vaccine inoculation I have had the satisfaction of seeing it extend very widely. Not only in this country is the subject pursued with ardour, but from my correspondence with many respectable medical gentlemen on the Continent (among whom are Dr. De Carro, of Vienna, and Dr. Ballhorn, of Hanover) I find it is as warmly adopted abroad, where it has afforded the greatest satisfaction. I have the pleasure, too, of seeing that the feeble efforts of a few individuals to depreciate the new practice are sinking fast into contempt beneath the immense mass of evidence which has arisen up in support of it. Upwards of six thousand persons have now been inoculated with the virus of cow-pox, and the far greater part of them have since been inoculated with that of smallpox, and exposed to its infection in every rational way that could be devised, without effect. It was very improbable that the investigation of a disease so analogous to the smallpox should go forward without engaging the attention of the physician of the Smallpox Hospital in London. Accordingly, Dr. Woodville, who fills that department with so much respectability, took an early opportunity of instituting an inquiry into the nature of the cow-pox. This inquiry was begun in the early part of the present year, and in May, Dr. Woodville published the result, which differs essentially from mine in a point of much importance. It appears that three-fifths of the patients inoculated were affected with eruptions, for the most part so perfectly resembling the smallpox as not to be distinguished from them. On this subject it is necessary that I should make some comments. When I consider that out of the great number of cases of casual inoculation immediately from cows which from time to time presented themselves to my observation, and the many similar instances which have been communicated to me by medical gentlemen in this neighbourhood; when I consider, too, that the matter with which my inoculations were conducted in the years 1797, '98, and '99, was taken from some different cows, and that in no instance any thing like a variolous pustule appeared, I cannot feel disposed to imagine that eruptions, similar to those described by Dr. Woodville, have ever been produced by the pure uncontaminated cow-pock virus; on the contrary, I do suppose that those which the doctor speaks of originated in the action of variolous matter which crept into the constitution with the vaccine. And this I presume happened from the inoculation of a great number of the patients with variolous matter (some on the third, others on the fifth, day) after the vaccine had been applied; and it should be observed that the matter thus propagated became the source of future inoculations in the hands of many medical gentlemen who appeared to have been previously unacquainted with the nature of the cow-pox. Another circumstance strongly, in my opinion, supporting this supposition is the following: The cow-pox has been known among our dairies time immemorial. If pustules, then, like the variolous, were to follow the communication of it from the cow to the milker, would not such a fact have been known and recorded at our farms? Yet neither our farmers nor the medical people of the neighbourhood have noticed such an occurrence. A few scattered pimples I have sometimes, though very rarely, seen, the greater part of which have generally disappeared quickly, but some have remained long enough to suppurate at their apex. That local cuticular inflammation, whether springing up spontaneously or arising from the application of acrid substances, such for instance, as cantharides, pix Burgundica, antimonium tartarizatum, etc., will often produce cutaneous affections, not only near the seat of the inflammation, but on some parts of the skin far beyond its boundary, is a well-known fact. It is, doubtless, on this principle that the inoculated cow-pock pustule and its concomitant efflorescence may, in very irritable constitutions, produce this affection. The eruption I allude to has commonly appeared some time in the third week after inoculation. But this appearance is too trivial to excite the least regard. The change which took place in the general appearance during the progress of the vaccine inoculation at the Smallpox Hospital should likewise be considered. Although at first it took on so much of the variolous character as to produce pustules in three cases out of five, yet in Dr. Woodville's last report, published in June, he says: "Since the publication of my reports of inoculations for the cow-pox, upwards of three hundred cases have been under my care; and out of this number only thirty-nine had pustules that suppurated; viz., out of the first hundred, nineteen had pustules; out of the second, thirteen; and out of the last hundred and ten, only seven had pustules. Thus it appears that the disease has become considerably milder; which I am inclined to attribute to a greater caution used in the choice of the matter, with which the infection was communicated; for, lately, that which has been employed for this purpose has been taken only from those patients in whom the cow-pox proved very mild and well characterized." [Footnote: In a few weeks after the cow-pox inoculation was introduced at the Smallpox Hospital I was favoured with some virus from this stock. In the first instance it produced a few pustules, which did not maturate; but in the subsequent cases none appeared.--E. J.] The inference I am induced to draw from these premises is very different. The decline, and, finally, the total extinction nearly, of these pustules, in my opinion, are more fairly attributable to the cow-pox virus, assimilating the variolous, [Footnote: In my first publication on this subject I expressed an opinion that the smallpox and the cow-pox were the same diseases under different modifications. In this opinion Dr. Woodville has concurred The axiom of the immortal Hauter, that two diseased actions cannot take place at the same time in one and the same part, will not be injured by the admission of this theory.] the former probably being the original, the latter the same disease under a peculiar, and at present an inexplicable, modification. One experiment tending to elucidate the point under discussion I had myself an opportunity of instituting. On the supposition of its being possible that the cow which ranges over the fertile meadows in the vale of Gloucester might generate a virus differing in some respects in its qualities from that produced by the animal artificially pampered for the production of milk for the metropolis, I procured, during my residence there in the spring, some cow pock virus from a cow at one of the London milk- farms. [Footnote: It was taken by Mr. Tanner, then a student at the Veterinary College, from a cow at Mr. Clark's farm at Kentish Town.] It was immediately conveyed into Gloucestershire to Dr. Marshall, who was then extensively engaged in the inoculation of the cow-pox, the general result of which, and of the inoculation in particular with this matter, I shall lay before my reader in the following communication from the doctor: "DEAR SIR: "My neighbour, Mr. Hicks, having mentioned your wish to be informed of the progress of the inoculation here for the cow-pox, and he also having taken the trouble to transmit to you my minutes of the cases which have fallen under my care, I hope you will pardon the further trouble I now give you in stating the observations I have made upon the subject. When first informed of it, having two children who had not had the smallpox, I determined to inoculate them for the cow-pox whenever I should be so fortunate as to procure matter proper for the purpose. I was, therefore, particularly happy when I was informed that I could procure matter from some of those whom you had inoculated. In the first instance I had no intention of extending the disease further than my own family, but the very extensive influence which the conviction of its efficacy in resisting the smallpox has had upon the minds of the people in general has rendered that intention nugatory, as you will perceive, by the continuation of my cases enclosed in this letter, [Footnote: Doctor Marshall has detailed these cases with great accuracy, but their publication would now be deemed superfluous.--E.J.] by which it will appear that since the 22d of March I have inoculated an hundred and seven persons; which, considering the retired situation I resided in, is a very great number. There are also other considerations which, besides that of its influence in resisting the smallpox, appear to have had their weight; the peculiar mildness of the disease, the known safety of it, and its not having in any instance prevented the patient from following his ordinary business. In all the cases under my care there have only occurred two or three which required any application, owing to erysipelatous inflammation on the arm, and they immediately yielded to it. In the remainder the constitutional illness has been slight but sufficiently marked, and considerably less than I ever observed in the same number inoculated with the smallpox. In only one or two of the cases have any other eruptions appeared than those around the spot where the matter was inserted, and those near the infected part. Neither does there appear in the cow-pox to be the least exciting cause to any other disease, which in the smallpox has been frequently observed, the constitution remaining in as full health and vigour after the termination of the disease as before the infection. Another important consideration appears to be the impossibility of the disease being communicated except by the actual contact of the matter of the pustule, and consequently the perfect safety of the remaining part of the family, supposing only one or two should wish to be inoculated at the same time. "Upon the whole, it appears evident to me that the cow-pox is a pleasanter, shorter, and infinitely more safe disease than the inoculated smallpox when conducted in the most careful and approved manner; neither is the local affection of the inoculated part, or the constitutional illness, near so violent. I speak with confidence on the subject, having had an opportunity of observing its effects upon a variety of constitutions, from three months old to sixty years; and to which I have paid particular attention. In the cases alluded to here you will observe that the removal from the original source of the matter had made no alteration or change in the nature or appearance of the disease, and that it may be continued, ad infinitum (I imagine), from one person to another (if care be observed in taking the matter at a proper period) without any necessity of recurring to the original matter of the cow. "I should be happy if any endeavours of mine could tend further to elucidate the subject, and shall be much gratified is sending you any further observations I may be enabled to make. "I have the pleasure to subscribe myself, "Dear sir, etc., "JOSEPH H. MARSHALL "EASTINGTON, GLOUCESTERSHIRE, April 26, 1799." The gentleman who favoured me with the above account has continued to prosecute his inquiries with unremitting industry, and has communicated the result in another letter, which at his request I lay before the public without abbreviation. Dr. Marshall's second letter: "DEAR SIR: "Since the date of my former letter I have continued to inoculate with the cow-pox virus. Including the cases before enumerated, the number now amounts to four hundred and twenty-three. It would be tedious and useless to detail the progress of the disease in each individual--it is sufficient to observe that I noticed no deviation in any respect from the cases I formerly adduced. The general appearances of the arm exactly corresponded with the account given in your first publication. When they were disposed to become troublesome by erysipelatous inflammation, an application of equal parts of vinegar and water always answered the desired intention. I must not omit to inform you that when the disease had duly acted upon the constitution I have frequently used the vitriolic acid. A portion of a drop applied with the head of a probe or any convenient utensil upon the pustule, suffered to remain about forty seconds, and afterwards washed off with sponge and water, never failed to stop its progress and expedite the formation of a scab. "I have already subjected two hundred and eleven of my patients to the action of variolous matter, but EVERY ONE RESISTED IT. "The result of my experiments (which were made with every requisite caution) has fully convinced me that the TRUE COW-POX is a safe and infallible preventive from the smallpox; that in no case which has fallen under my observation has it been in any considerable degree troublesome, much less have I seen any thing like danger; for in no instance were the patients prevented from following their ordinary employments. "In Dr. Woodville's publication on the cow-pox I notice an extraordinary fact. He says that the generality of his patients had pustules. It certainly appears extremely extraordinary that in all my cases there never was but one pustule, which appeared on a patient's elbow on the inoculated arm, and maturated. It appeared exactly like that on the incised part. "The whole of my observations, founded as it appears on an extensive experience, leads me to these obvious conclusions; that those cases which have been or may be adduced against the preventive powers of the cow-pox could not have been those of the true kind, since it must appear to be absolutely impossible that I should have succeeded in such a number of cases without a single exception if such a preventive power did not exist. I cannot entertain a doubt that the inoculated cow-pox must quickly supersede that of the smallpox. If the many important advantages which must result from the new practice are duly considered, we may reasonably infer that public benefit, the sure test of the real merit of discoveries, will render it generally extensive. "To you, Sir, as the discoverer of this highly beneficial practice, mankind are under the highest obligations. As a private individual I participate in the general feeling; more particularly as you have afforded me an opportunity of noticing the effects of a singular disease, and of viewing the progress of the most curious experiment that ever was recorded in the history of physiology. "I remain, dear sir, etc., "JOSEPH H. MARSHALL." "P.S. I should have observed that, of the patients I inoculated and enumerated in my letter, one hundred and twenty-seven were infected with the matter you sent me from the London cow. I discovered no dissimilarity of symptoms in these cases from those which I inoculated from matter procured in this country. No pustules have occurred, except in one or two cases, where a single one appeared on the inoculated arm. No difference was apparent in the local inflammation. There was no suspension of ordinary employment among the labouring people, nor was any medicine required. "I have frequently inoculated one or two in a family, and the remaining part of it some weeks afterwards. The uninfected have slept with the infected during the whole course of the disease without being affected; so that I am fully convinced that the disease cannot be taken but by actual contact with the matter. "A curious fact has lately fallen under my observation, on which I leave you to comment. "I visited a patient with the confluent smallpox and charged a lancet with some of the matter. Two days afterwards I was desired to inoculate a woman and four children with the cow-pox, and I inadvertently took the vaccine matter on the same lancet which was before charged with that of smallpox. In three days I discovered the mistake, and fully expected that my five patients would be infected with smallpox; but I was agreeably surprised to find the disease to be genuine cow-pox, which proceeded without deviating in any particular from my former cases. I afterwards inoculated these patients with variolous matter, but all of them resisted its action. "I omitted mentioning another great advantage that now occurs to me in the inoculated cow-pox; I mean, the safety with which pregnant women may have the disease communicated to them. I have inoculated a great number of females in that situation, and never observed their cases to differ in any respect from those of my other patients. Indeed, the disease is so mild that it seems as if it might at all times be communicated with the most perfect safety." I shall here take the opportunity of thanking Dr. Marshall and those other gentlemen who have obligingly presented me with the result of their inoculations; but, as they all agree in the same point as that given in the above communication, namely, the security of the patient from the effects of the smallpox after the cow-pox, their perusal, I presume, would afford us no satisfaction that has not been amply given already. Particular occurrences I shall, of course, detail. Some of my correspondents have mentioned the appearance of smallpox-like eruptions at the commencement of their inoculations; but in these cases the matter was derived from the original stock at the Smallpox Hospital. I have myself inoculated a very considerable number from the matter produced by Dr. Marshall's patients, originating in the London cow, without observing pustules of any kind, and have dispersed it among others who have used it with a similar effect. From this source Mr. H. Jenner informs me he has inoculated above an hundred patients without observing eruptions. Whether the nature of the virus will undergo any change from being farther removed from its original source in passing successively from one person to another time alone can determine. That which I am now employing has been in use near eight months, and not the least change is perceptible in its mode of action either locally or constitutionally. There is, therefore, every reason to expect that its effects will remain unaltered and that we shall not be under the necessity of seeking fresh supplies from the cow. The following observations were obligingly sent me by Mr. Tierny, Assistant Surgeon to the South Gloucester Regiment of Militia, to whom I am indebted for a former report on this subject: "I inoculated with the cow-pox matter from the eleventh to the latter part of April, twenty-five persons, including women and children. Some on the eleventh were inoculated with the matter Mr. Shrapnell (surgeon to the regiment) had from you, the others with matter taken from these. The progress of the puncture was accurately observed, and its appearance seemed to differ from the smallpox in having less inflammation around its basis on the first days--that is, from the third to the seventh; but after this the inflammation increased, extending on the tenth or eleventh day to a circle of an inch and a half from its centre, and threatening very sore arms; but this I am happy to say was not the case; for, by applying mercurial ointment to the inflamed part, which was repeated daily until the inflammation went off, the arm got well without any further application or trouble. The constitutional symptoms which appeared on the eighth or ninth day after inoculation scarcely deserved the name of disease, as they were so slight as to be scarcely perceptible, except that I could connect a slight headache and languor, with a stiffness and rather painful sensation in the axilla. This latter symptom was the most striking--it remained from twelve to forty-eight hours. In no case did I observe the smallest pustule, or even discolouration of the skin, like an incipient pustule, except about the part where the virus has been applied. "After all these symptoms had subsided and the arms were well, I inoculated four of this number with variolous matter, taken from a patient in another regiment. In each of these it was inserted several times under the cuticle, producing slight inflammation on the second or third day, and always disappearing before the fifth or sixth, except in one who had the cow-pox in Gloucestershire before he joined us, and who also received it at this time by inoculation. In this man the puncture inflamed and his arm was much sorer than from the insertion of the cow-pox virus; but there was no pain in the axilla, nor could any constitutional affection be observed. "I have only to add that I am now fully satisfied of the efficacy of the cow-pox in preventing the appearance of the smallpox, and that it is a most happy and salutary substitute for it. I remain, etc., "M. J. TIERNY." Although the susceptibility of the virus of the cow-pox is, for the most part, lost in those who have had the smallpox, yet in some constitutions it is only partially destroyed, and in others it does not appear to be in the least diminished. By far the greater number on whom trials were made resisted it entirely; yet I found some on whose arm the pustule from inoculation was formed completely, but without producing the common efflorescent blush around it, or any constitutional illness, while others have had the disease in the most perfect manner. A case of the latter kind having been presented to me by Mr. Fewster, Surgeon, of Thornbury, I shall insert it: "Three children were inoculated with the vaccine matter you obligingly sent me. On calling to look at their arms three days after I was told that John Hodges, one of the three, had been inoculated with the smallpox when a year old, and that he had a full burthen, of which his face produced plentiful marks, a circumstance I was not before made acquainted with. On the sixth day the arm of the boy appeared as if inoculated with variolous matter, but the pustule was rather more elevated. On the ninth day he complained of violent pain in his head and back, accompanied with vomiting and much fever. The next day he was very well and went to work as usual. The punctured part began to spread, and there was the areola around the inoculated part to a considerable extent. "As this is contrary to an assertion made in the Medical and Physical Journal, No. 8, I thought it right to give you this information, and remain, "Dear sir, etc., "J. FEWSTER." It appears, then, that the animal economy with regard to the action of this virus is under the same laws as it is with respect to the variolous virus, after previously feeling its influence, as far as comparisons can be made between the two diseases. Some striking instances of the power of the cow-pox in suspending the progress of the smallpox after the patients had been several days casually exposed to the infection have been laid before me by Mr. Lyford, Surgeon, of Winchester, and my nephew, the Rev. G. C Jenner. Mr. Lyford, after giving an account of his extensive and successful practice in the vaccine inoculation in Hampshire, writes as follows: "The following case occurred to me a short time since, and may probably be worth your notice. I was sent for to a patient with the smallpox, and on inquiry found that five days previous to my seeing him the eruption began to appear. During the whole of this time two children who had not had the smallpox, were constantly in the room with their father, and frequently on the bed with him. The mother consulted me on the propriety of inoculating them, but objected to my taking the matter from their father, as he was subject to erysipelas. I advised her by all means to have them inoculated at that time, as I could not procure any variolous matter elsewhere. However, they were inoculated with vaccine matter, but I cannot say I flattered myself with its proving successful, as they had previously been so long and still continued to be exposed to the variolous infection. Notwithstanding this I was agreeably surprised to find the vaccine disease advance and go through its regular course; and, if I may be allowed the expression, to the total extinction of the smallpox." Mr. Jenner's cases were not less satisfactory. He writes as follows: "A son of Thomas Stinchcomb, of Woodford, near Berkeley, was infected with the natural smallpox at Bristol, and came home to his father's cottage. Four days after the eruptions had appeared upon the boy, the family (none of which had ever had the smallpox), consisting of the father, mother, and five children, was inoculated with vaccine virus. On the arm of the mother it failed to produce the least effect, and she, of course, had the smallpox, [Footnote: Under similar circumstances I think it would be advisable to insert the matter into each arm, which would be more likely to insure the success of the operation.--E. J.] but the rest of the family had the cow-pox in the usual way, and were not affected with the smallpox, although they were in the same room, and the children slept in the same bed with their brother who was confined to it with the natural smallpox; and subsequently with their mother. "I attended this family with my brother, Mr. H. Jenner." The following cases are of too singular a nature to remain unnoticed. Miss R--, a young lady about five years old, was seized on the evening of the eighth day after inoculation with vaccine virus, with such symptoms as commonly denote the accession of violent fever. Her throat was also a little sore, and there were some uneasy sensations about the muscles of the neck. The day following a rash was perceptible on her face and neck, so much resembling the efflorescence of the scarlatina anginosa that I was induced to ask whether Miss R--had been exposed to the contagion of that disease. An answer in the affirmative, and the rapid spreading of the redness over the skin, at once relieved me from much anxiety respecting the nature of the malady, which went through its course in the ordinary way, but not without symptoms which were alarming both to myself and Mr. Lyford, who attended with me. There was no apparent deviation in the ordinary progress of the pustule to a state of maturity from what we see in general; yet there was a total suspension of the areola or florid discolouration around it, until the scarlatina had retired from the constitution. As soon as the patient was freed from this disease this appearance advanced in the usual way. [Footnote: I witnessed a similar fact in a case of measles. The pustule from the cow-pock virus advanced to maturity, while the measles existed in the constitution, but no EFFLORESCENCE appeared around it until the measles had ceased to exert its influence.] The case of Miss H--R--is not less interesting than that of her sister, above related. She was exposed to the contagion of the scarlatina at the same time, and sickened almost at the same hour. The symptoms continued severe about twelve hours, when the scarlatina-rash shewed itself faintly upon her face, and partly upon her neck. After remaining two or three hours it suddenly disappeared, and she became perfectly free from every complaint. My surprise at this sudden transition from extreme sickness to health in great measure ceased when I observed that the inoculated pustule had occasioned, in this case, the common efflorescent appearance around it, and that as it approached the centre it was nearly in an erysipelatous state. But the most remarkable part of this history is that, on the fourth day afterwards, so soon as the efflorescence began to die away upon the arm and the pustule to dry up, the scarlatina again appeared, her throat became sore, the rash spread all over her. She went fairly through the disease with its common symptoms. That these were actually cases of scarlatina was rendered certain by two servants in the family falling ill at the same time with the distemper, who had been exposed to the infection with the young ladies. Some there are who suppose the security from the smallpox obtained through the cow-pox will be of a temporary nature only. This supposition is refuted not only by analogy with respect to the habits of diseases of a similar nature, but by incontrovertible facts, which appear in great numbers against it. To those already adduced in the former part of my first treatise [Footnote: See pages 217, 218, 219, 221, 223, etc.] many more might be adduced were it deemed necessary; but among the cases I refer to, one will be found of a person who had the cow-pox fifty-three years before the effect of the smallpox was tried upon him. As he completely resisted it, the intervening period I conceive must necessarily satisfy any reasonable mind. Should further evidence be thought necessary, I shall observe that, among the cases presented to me by Mr. Fry, Mr. Darke, Mr. Tierny, Mr. H. Jenner, and others, there were many whom they inoculated ineffectually with variolous matter, who had gone through the cow-pox many years before this trial was made. It has been imagined that the cow-pox is capable of being communicated from one person to another by effluvia without the intervention of inoculation. My experiments, made with the design of ascertaining this important point, all tend to establish my original position, that it is not infectious except by contact, I have never hesitated to suffer those on whose arms there were pustules exhaling the effluvia from associating or even sleeping with others who never had experienced either the cow-pox or the smallpox. And, further, I have repeatedly, among children, caused the uninfected to breathe over the inoculated vaccine 'pustules during their whole progress, yet these experiments were tried without the least effect. However, to submit a matter so important to a still further scrutiny, I desired Mr. H. Jenner to make any further experiments which might strike him as most likely to establish or refute what had been advanced on this subject. He has since informed me "that he inoculated children at the breast, whose mothers had not gone through either the smallpox or the cow-pox; that he had inoculated mothers whose sucking infants had never undergone either of these diseases; that the effluvia from the inoculated pustules, in either case, had been inhaled from day to day during the whole progress of their maturation, and that there was not the least perceptible effect from these exposures." One woman he inoculated about a week previous to her accouchement, that her infant might be the more fully and conveniently exposed to the pustule; but, as in the former instances, no infection was given, although the child frequently slept on the arm of its mother with its nostrils and mouth exposed to the pustule in the fullest state of maturity. In a word, is it not impossible for the cow-pox, whose ONLY manifestation appears to consist in the pustules CREATED BY CONTACT, to produce ITSELF by effluvia? In the course of a late inoculation I observed an appearance which it may be proper here to relate. The punctured part on a boy's arm (who was inoculated with fresh limpid virus) on the sixth day, instead of shewing a beginning vesicle, which is usual in the cow-pox at that period, was encrusted over with a rugged, amber-coloured scab. The scab continued to spread and increase in thickness for some days, when, at its edges, a vesicated ring appeared, and the disease went through its ordinary course, the boy having had soreness in the axilla and some slight indisposition. With the fluid matter taken from his arm five persons were inoculated. In one it took no effect. In another it produced a perfect pustule without any deviation from the common appearance; but in the other three the progress of the inflammation was exactly similar to the instance which afforded the virus for their inoculation; there was a creeping scab of a loose texture, and subsequently the formation of limpid fluid at its edges. As these people were all employed in laborious exercises, it is possible that these anomalous appearances might owe their origin to the friction of the clothes on the newly inflamed part of the arm. I have not yet had an opportunity of exposing them to the smallpox. In the early part of this inquiry I felt far more anxious respecting the inflammation of the inoculated arm than at present; yet that this affection will go on to a greater extent than could be wished is a circumstance sometimes to be expected. As this can be checked, or even entirely subdued, by very simple means, I see no reason why the patient should feel an uneasy hour because an application may not be absolutely necessary. About the tenth or eleventh day, if the pustule has proceeded regularly, the appearance of the arm will almost to a certainty indicate whether this is to be expected or not. Should it happen, nothing more need be done than to apply a single drop of the aqua lythargyri acetati [Footnote: Extract of Saturn.] upon the pustule, and, having suffered it to remain two or three minutes, to cover the efflorescence surrounding the pustule with a piece of linen dipped in the aqua lythargyri compos. [Footnote: Goulard water. For further information on this subject see the first Treatise on the Var. Vac., Dr. Marshall's letters, etc.] The former may be repeated twice or thrice during the day, the latter as often as it may feel agreeable to the patient. When the scab is prematurely rubbed off (a circumstance not unfrequent among children and working people), the application of a little aqua lythargyri acet. to the part immediately coagulates the surface, which supplies its place, and prevents a sore. In my former treatises on this subject I have remarked that the human constitution frequently retains its susceptibility to the smallpox contagion (both from effluvia and contact) after previously feeling its influence. In further corroboration of this declaration many facts have been communicated to me by various correspondents. I shall select one of them. "DEAR SIR: "Society at large must, I think, feel much indebted to you for your Inquiries and Observations on the Nature and Effects of the Variolae Vaccinae, etc., etc. As I conceive what I am now about to communicate to be of some importance, I imagine it cannot be uninteresting to you, especially as it will serve to corroborate your assertion of the susceptibility of the human system of the variolous contagion, although it has previously been made sensible of its action. In November, 1793, I was desired to inoculate a person with the smallpox. I took the variolous matter from a child under the disease in the natural way, who had a large burthen of distinct pustules. The mother of the child being desirous of seeing my method of communicating the disease by inoculation, after having opened a pustule, I introduced the point of my lancet in the usual way on the back part of my own hand, and thought no more of it until I felt a sensation in the part which reminded me of the transaction. This happened upon the third day; on the fourth there were all the appearances common to inoculation, at which I was not at all surprised, nor did I feel myself uneasy upon perceiving the inflammation continue to increase to the sixth and seventh day, accompanied with a very small quantity of fluid, repeated experiments having taught me it might happen so with persons who had undergone the disease, and yet would escape any constitutional affection; but I was not so fortunate; for on the eighth day I was seized with all the symptoms of the eruptive fever, but in a much more violent degree than when I was before inoculated, which was about eighteen years previous to this, when I had a considerable number of pustules. I must confess I was now greatly alarmed, although I had been much engaged in the smallpox, having at different times inoculated not less than two thousand persons. I was convinced my present indisposition proceeded from the insertion of the variolous matter, and, therefore, anxiously looked for an eruption. On the tenth day I felt a very unpleasant sensation of stillness and heat on each side of my face near my ear, and the fever began to decline. The affection in my face soon terminated in three or four pustules attended with inflammation, but which did not maturate, and I was presently well. "I remain, dear sir, etc., "THOMAS MILES." This inquiry is not now so much in its infancy as to restrain me from speaking more positively than formerly on the important point of scrophula as connected with the smallpox. Every practitioner in medicine who has extensively inoculated with the smallpox, or has attended many of those who have had the distemper in the natural way, must acknowledge that he has frequently seen scrophulous affections, in some form or another, sometimes rather quickly shewing themselves after the recovery of the patients. Conceiving this fact to be admitted, as I presume it must be by all who have carefully attended to the subject, may I not ask whether it does not appear probable that the general introduction of the smallpox into Europe has not been among the most conductive means in exciting that formidable foe to health? Having attentively watched the effects of the cow-pox in this respect, I am happy in being able to declare that the disease does not appear to have the least tendency to produce this destructive malady. The scepticism that appeared, even among the most enlightened of medical men when my sentiments on the important subject of the cow-pox were first promulgated, was highly laudable. To have admitted the truth of a doctrine, at once so novel and so unlike any thing that ever had appeared in the annals of medicine, without the test of the most rigid scrutiny, would have bordered upon temerity; but now, when that scrutiny has taken place, not only among ourselves, but in the first professional circles in Europe, and when it has been uniformly found in such abundant instances that the human frame, when once it has felt the influence of the genuine cow-pox in the way that has been described, is never afterwards at any period of its existence assailable by the smallpox, may I not with perfect confidence congratulate my country and society at large on their beholding, in the mild form of the cow-pox, an antidote that is capable of extirpating from the earth a disease which is every hour devouring its victims; a disease that has ever been considered as the severest scourge of the human race! THE CONTAGIOUSNESS OF PUERPERAL FEVER BY OLIVER WENDELL HOLMES INTRODUCTORY NOTE Oliver Wendell Holmes was born in Cambridge, Massachusetts, August 29, 1809, and educated at Phillips Academy, Andover, and Harvard College. After graduation, he entered the Law School, but soon gave up law for medicine. He studied first in Boston, and later spent two years in medical schools in Europe, mainly in Paris. On his return he began to practise in Boston, but in two years he was appointed professor of anatomy at Dartmouth College, a position which he held from 1838 to 1840, when he again took up his Boston practise. It was soon after this, in 1843, that he published his essay on the "Contagiousness of Puerperal Fever," his only contribution of high distinction to medical science. From 1847 to 1882 he was Parkman professor of anatomy and physiology in the Harvard Medical School. He died in Boston, October 7, 1894. In spite of the importance of the paper here printed, Holmes's reputation as a scientist was overshadowed by that won by him as a wit and a man of letters. When he was only twenty-one his "Old Ironsides" brought him into notice; and through his poetry and fiction, and the sparkling talk of the "Breakfast Table" series, he took a high place among the most distinguished group of writers that America has yet produced. THE CONTAGIOUSNESS OF PUERPERAL FEVER Note.--This essay appeared first in 1843, in The New England Quarterly Journal of Medicine, and was reprinted in the "Medical Essays" in 1855. In collecting, enforcing and adding to the evidence accumulated upon this most serious subject, I would not be understood to imply that there exists a doubt in the mind of any well-informed member of the medical profession as to the fact that puerperal fever is sometimes communicated from one person to another, both directly and indirectly. In the present state of our knowledge upon this point I should consider such doubts merely as a proof that the sceptic had either not examined the evidence, or, having examined it, refused to accept its plain and unavoidable consequences. I should be sorry to think, with Dr. Rigby, that it was a case of "oblique vision"; I should be unwilling to force home the argumentum ad hominem of Dr. Blundell, but I would not consent to make a question of a momentous fact which is no longer to be considered as a subject for trivial discussions, but to be acted upon with silent promptitude. It signifies nothing that wise and experienced practitioners have sometimes doubted the reality of the danger in question; no man has the right to doubt it any longer. No negative facts, no opposing opinions, be they what they may, or whose they may, can form any answer to the series of cases now within the reach of all who choose to explore the records of medical science. If there are some who conceive that any important end would be answered by recording such opinions, or by collecting the history of all the cases they could find in which no evidence of the influence of contagion existed, I believe they are in error. Suppose a few writers of authority can be found to profess a disbelief in contagion,--and they are very few compared with those who think differently,--is it quite clear that they formed their opinions on a view of all the facts, or is it not apparent that they relied mostly on their own solitary experience? Still further, of those whose names are quoted, is it not true that scarcely a single one could, by any possibility, have known the half or the tenth of the facts bearing on the subject which have reached such a frightful amount within the last few years? Again, as to the utility of negative facts, as we may briefly call them,--instances, namely, in which exposure has not been followed by disease,--although, like other truths, they may be worth knowing, I do not see that they are like to shed any important light upon the subject before us. Every such instance requires a good deal of circumstantial explanation before it can be accepted. It is not enough that a practitioner should have had a single case of puerperal fever not followed by others. It must be known whether he attended others while this case was in progress, whether he went directly from one chamber to others, whether he took any, and what, precautions. It is important to know that several women were exposed to infection derived from the patient, so that allowance may be made for want of predisposition. Now, if of negative facts so sifted there could be accumulated a hundred for every one plain instance of communication here recorded, I trust it need not be said that we are bound to guard and watch over the hundredth tenant of our fold, though the ninety and nine may be sure of escaping the wolf at its entrance. If any one is disposed, then, to take a hundred instances of lives, endangered or sacrificed out of those I have mentioned, and make it reasonably clear that within a similar time and compass TEN THOUSAND escaped the same exposure, I shall, thank him for his industry, but I must be permitted to hold to my own practical conclusions, and beg him to adopt or at least to examine them also. Children that walk in calico before open fires are not always burned to death; the instances to the contrary may be worth recording; but by no means if they are to be used as arguments against woollen frocks and high fenders. I am not sure that this paper will escape another remark which it might be wished were founded in justice. It may be said that the facts are too generally known and acknowledged to require any formal argument or exposition, that there is nothing new in the positions advanced, and no need of laying additional statements before the profession. But on turning to two works, one almost universally, and the other extensively, appealed to as authority in this country, I see ample reason to overlook this objection. In the last edition of Dewees's Treatise on the "Diseases of Females" it is expressly said, "In this country, under no circumstance that puerperal fever has appeared hitherto, does it afford the slightest ground for the belief that it is contagious." In the "Philadelphia Practice of Midwifery" not one word can be found in the chapter devoted to this disease which would lead the reader to suspect that the idea of contagion had ever been entertained. It seems proper, therefore, to remind those who are in the habit of referring to the works for guidance that there may possibly be some sources of danger they have slighted or omitted, quite as important as a trifling irregularity of diet, or a confined state of the bowels, and that whatever confidence a physician may have in his own mode of treatment, his services are of questionable value whenever he carries the bane as well as the antidote about his person. The practical point to be illustrated is the following: THE DISEASE KNOWN AS PUERPERAL FEVER IS SO FAR CONTAGIOUS AS TO BE FREQUENTLY CARRIED FROM PATIENT TO PATIENT BY PHYSICIANS AND NURSES. Let me begin by throwing out certain incidental questions, which, without being absolutely essential, would render the subject more complicated, and by making such concessions and assumptions as may be fairly supposed to be without the pale of discussion. 1. It is granted that all the forms of what is called puerperal fever may not be, and probably are not, equally contagious or infectious. I do not enter into the distinctions which have been drawn by authors, because the facts do not appear to me sufficient to establish any absolute line of demarcation between such forms as may be propagated by contagion and those which are never so propagated. This general result I shall only support by the authority of Dr. Ramsbotham, who gives, as the result of his experience, that the same symptoms belong to what he calls the infectious and the sporadic forms of the disease, and the opinion of Armstrong in his original Essay. If others can show any such distinction, I leave it to them to do it. But there are cases enough that show the prevalence of the disease among the patients of a single practitioner when it was in no degree epidemic; in the proper sense of the term. I may refer to those of Mr. Roberton and of Dr. Peirson, hereafter to be cited, as examples. 2. I shall not enter into any dispute about the particular MODE of infection, whether it be by the atmosphere the physician carries about him into the sick-chamber, or by the direct application of the virus to the absorbing surfaces with which his hand comes in contact. Many facts and opinions are in favour of each of these modes of transmission. But it is obvious that, in the majority of cases, it must be impossible to decide by which of these channels the disease is conveyed, from the nature of the intercourse between the physician and the patient. 3. It is not pretended that the contagion of puerperal fever must always be followed by the disease. It is true of all contagious diseases that they frequently spare those who appear to be fully submitted to their influence. Even the vaccine virus, fresh from the subject, fails every day to produce its legitimate effect, though every precaution is taken to insure its action. This is still more remarkably the case with scarlet fever and some other diseases. 4. It is granted that the disease may be produced and variously modified by many causes besides contagion, and more especially by epidemic and endemic influences. But this is not peculiar to the disease in question. There is no doubt that smallpox is propagated to a great extent by contagion, yet it goes through the same records of periodical increase and diminution which have been remarked in puerperal fever. If the question is asked how we are to reconcile the great variations in the mortality of puerperal fever in different seasons and places with the supposition of contagion, I will answer it by another question from Mr. Farr's letter to the Registrar-General. He makes the statement that "FIVE die weekly of smallpox in the metropolis when the disease is not epidemic," and adds, "The problem for solution is, Why do the five deaths become 10, 15, 20, 31, 58, 88, weekly, and then progressively fall through the same measured steps?" 5. I take it for granted that if it can be shown that great numbers of lives have been and are sacrificed to ignorance or blindness on this point, no other error of which physicians or nurses may be occasionally suspected will be alleged in palliation of this; but that whenever and wherever they can be shown to carry disease and death instead of health and safety, the common instincts of humanity will silence every attempt to explain away their responsibility. The treatise of Dr. Gordon, of Aberdeen, was published in the year 1795, being among the earlier special works upon the disease. A part of his testimony has been occasionally copied into other works, but his expressions are so clear, his experience is given with such manly distinctness and disinterested honesty, that it may be quoted as a model which might have been often followed with advantage. "This disease seized such women only as were visited or delivered by a practitioner, or taken care of by a nurse, who had previously attended patients affected with the disease." "I had evident proofs of its infectious nature, and that the infection was as readily communicated as that of the smallpox or measles, and operated more speedily than any other infection with which I am acquainted." "I had evident proofs that every person who had been with a patient in the puerperal fever became charged with an atmosphere of infection, which was communicated to every pregnant woman who happened to come within its sphere. This is not an assertion, but a fact, admitting of demonstration, as may be seen by a perusal of the foregoing table"--referring to a table of seventy-seven cases, in many of which the channel of propagation was evident. He adds: "It is a disagreeable declaration for me to mention, that I myself was the means of carrying the infection to a great number of women." He then enumerates a number of instances in which the disease was conveyed by midwives and others to the neighboring villages, and declares that "these facts fully prove that the cause of the puerperal fever, of which I treat, was a specific contagion, or infection, altogether unconnected with a noxious constitution of the atmosphere." But his most terrible evidence is given in these words: "I ARRIVED AT THAT CERTAINTY IN THE MATTER THAT I COULD VENTURE TO FORETELL WHAT WOMEN WOULD BE AFFECTED WITH THE DISEASE, UPON HEARING BY WHAT MIDWIFE THEY WERE TO BE DELIVERED, OR BY WHAT NURSE THEY WERE TO BE ATTENDED, DURING THEIR LYING-IN: AND ALMOST IN EVERY INSTANCE MY PREDICTION WAS VERIFIED." Even previously to Gordon, Mr. White, of Manchester, had said: "I am acquainted with two gentlemen in another town, where the whole business of midwifery is divided betwixt them, and it is very remarkable that one of them loses several patients every year of the puerperal fever, and the other never so much as meets with the disorder"--a difference which he seems to attribute to their various modes of treatment. [Footnote: On the Management of Lying-in Women. p. 120.] Dr. Armstrong has given a number of instances in his Essay on Puerperal Fever of the prevalence of the disease among the patients of a single practitioner. At Sunderland, "in all, forty- three cases occurred from the 1st of January to the 1st of October, when the disease ceased; and of this number, forty were witnessed by Mr. Gregson and his assistant, Mr. Gregory, the remainder having been separately seen by three accoucheurs." There is appended to the London edition of this Essay a letter from Mr. Gregson, in which that gentleman says, in reference to the great number of cases occurring in his practice, "The cause of this I cannot pretend fully to explain, but I should be wanting in common liberality if I were to make any hesitation in asserting that the disease which appeared in my practice was highly contagious, and communicable from one puerperal woman to another." "It is customary among the lower and middle ranks of people to make frequent personal visits to puerperal women resident in the same neighborhood, and I have ample evidence for affirming that the infection of the disease was often carried about in that manner; and, however painful to my feelings, I must in candour declare that it is very probable the contagion was conveyed, in some instances, by myself, though I took every possible care to prevent such a thing from happening the moment that I ascertained that the distemper was infectious." Dr. Armstrong goes on to mention six other instances within his knowledge, in which the disease had at different times and places been limited, in the same singular manner, to the practice of individuals, while it existed scarcely, if at all, among the patients of others around them. Two of the gentlemen became so convinced of their conveying the contagion that they withdrew for a time from practice. I find a brief notice, in an American journal, of another series of cases, first mentioned by Mr. Davies, in the "Medical Repository." This gentleman stated his conviction that the disease is contagious. "In the autumn of 1822 he met with twelve cases, while his medical friends in the neighbourhood did not meet with any, 'or at least very few.' He could attribute this circumstance to no other cause than his having been present at the examination after death, of two cases, some time previous, and of his having imparted the disease to his patients, notwithstanding every precaution." [Footnote: Philad. Med. Journal for 1825, p. 408.] Dr. Gooch says: "It is not uncommon for the greater number of cases to occur in the practice of one man, whilst the other practitioners of the neighborhood, who are not more skilful or more busy, meet with few or none. A practitioner opened the body of a woman who had died of puerperal fever, and continued to wear the same clothes. A lady whom he delivered a few days afterwards was attacked with and died of a similar disease; two more of his lying-in patients, in rapid succession, met with the same fate; struck by the thought that he might have carried contagion in his clothes, he instantly changed them, and met with no more cases of the kind. [Footnote: A similar anecdote is related by Sir Benjamin Brodie, of the late Dr. John Clark, Lancet, May 2, 1840.] A woman in the country who was employed as washerwoman and nurse washed the linen of one who had died of puerperal fever; the next lying-in patient she nursed died of the same disease; a third nursed by her met the same fate, till the neighbourhood, getting afraid of her, ceased to employ her." [Footnote: An Account of Some of the Most Important Diseases Peculiar to Women, p. 4]. In the winter of the year 1824, "several instances occurred of its prevalence among the patients of particular practitioners, whilst others who were equally busy met with few or none. One instance of this kind was very remarkable. A general practitioner, in large midwifery practice, lost so many patients from puerperal fever that he determined to deliver no more for some time, but that his partner should attend in his place. This plan was pursued for one month, during which not a case of the disease occurred in their practice. The elder practitioner, being then sufficiently recovered, returned to his practice, but the first patient he attended was attacked by the disease and died. A physician who met him in consultation soon afterwards, about a case of a different kind, and who knew nothing of his misfortune, asked him whether puerperal fever was at all prevalent in his neighbourhood, on which he burst into tears, and related the above circumstances. "Among the cases which I saw this season in consultation, four occurred in one month in the practice of one medical man, and all of them terminated fatally." [Footnote: Gooch, op. cit., p. 71.] Dr. Ramsbotham asserted, in a lecture at the London Hospital, that he had known the disease spread through a particular district, or be confined to the practice of a particular person, almost every patient being attacked with it, while others had not a single case. It seemed capable, he thought, of conveyance, not only by common modes, but through the dress of the attendants upon the patient. [Footnote: Lond. Med. Gaz., May 2, 1835.] In a letter to be found in the "London Medical Gazette" for January, 1840, Mr. Roberton, of Manchester, makes the statement which I here give in a somewhat condensed form. A midwife delivered a woman on the 4th of December, 1830, who died soon after with the symptoms of puerperal fever. In one month from this date the same midwife delivered thirty women, residing in different parts of an extensive suburb, of which number sixteen caught the disease and all died. These were the only cases which had occurred for a considerable time in Manchester. The other midwives connected with the same charitable institution as the woman already mentioned are twenty-five in number, and deliver, on an average, ninety women a week, or about three hundred and eighty a month. None of these women had a case of puerperal fever. "Yet all this time this woman was crossing the other midwives in every direction, scores of the patients of the charity being delivered by them in the very same quarters where her cases of fever were happening." Mr. Roberton remarks that little more than half the women she delivered during this month took the fever; that on some days all escaped, on others only one or more out of three or four; a circumstance similar to what is seen in other infectious maladies. Dr. Blundell says: "Those who have never made the experiment can have but a faint conception how difficult it is to obtain the exact truth respecting any occurrence in which feelings and interests are concerned. Omitting particulars, then, I content myself with remarking, generally, that from more than one district I have received accounts of the prevalence of puerperal fever in the practice of some individuals, while its occurrence in that of others, in the same neighborhood, was not observed. Some, as I have been told, have lost ten, twelve, or a greater number of patients, in scarcely broken succession; like their evil genius, the puerperal fever has seemed to stalk behind them wherever they went. Some have deemed it prudent to retire for a time from practice. In fine, that this fever may occur spontaneously, I admit; that its infectious nature may be plausibly disputed, I do not deny; but I add, considerately, that in my own family I had rather that those I esteemed the most should be delivered, unaided, in a stable, by the mangerside, than that they should receive the best help, in the fairest apartment, but exposed to the vapors of this pitiless disease. Gossiping friends, wet-nurses, monthly nurses, the practitioner himself, these are the channels by which, as I suspect, the infection is principally conveyed." [Footnote: Lect. on Midwifery, p. 395.] At a meeting of the Royal Medical and Chirurgical Society Dr. King. mentioned that some years since a practitioner at Woolwich lost sixteen patients from puerperal fever in the same year. He was compelled to give up practice for one or two years, his business being divided among the neighboring practitioners. No case of puerperal fever occurred afterwards, neither had any of the neighboring surgeons any cases of this disease. At the same meeting Mr. Hutchinson mentioned the occurrence of three consecutive cases of puerperal fever, followed subsequently by two others, all in the practice of one accoucheur. [Footnote: Lancet, May 3, 1840.] Dr. Lee makes the following statement: "In the last two weeks of September, 1827, five fatal cases of uterine inflammation came under our observation. All the individuals so attacked had been attended in labor by the same midwife, and no example of a febrile or inflammatory disease of a serious nature occurred during that period among the other patients of the Westminster General Dispensary, who had been attended by the other midwives belonging to that institution." [Footnote: Lond. Cyc. of Pract. Med., art., "Fever, Puerperal"] The recurrence of long series of cases like those I have cited, reported by those most interested to disbelieve in contagion, scattered along through an interval of half a century, might have been thought sufficient to satisfy the minds of all inquirers that here was something more than a singular coincidence. But if, on a more extended observation, it should be found that the same ominous groups of cases clusterings about individual practitioners were observed in a remote country, at different times, and in widely separated regions, it would seem incredible that any should be found too prejudiced or indolent to accept the solemn truth knelled into their ears by the funeral bells from both sides of the ocean--the plain conclusion that the physician and the disease entered, hand in hand, into the chamber of the unsuspecting patient. That such series of cases have been observed in this country, and in this neighborhood, I proceed to show. In Dr. Francis's "Notes to Denman's Midwifery" a passage is cited from Dr. Hosack in which he refers to certain puerperal cases which proved fatal to several lying-in women, and in some of which the disease was supposed to be conveyed by the accoucheurs themselves. [Footnote: Denman's Midwifery, p. 673, third Am. ed.] A writer in the "New York Medical and Physical Journal" for October, 1829, in speaking of the occurrence of puerperal fever confined to one man's practice, remarks: "We have known cases of this kind occur, though rarely, in New York." I mention these little hints about the occurrence of such cases partly because they are the first I have met with in American medical literature, but more especially because they serve to remind us that behind the fearful array of published facts there lies a dark list of similar events, unwritten in the records of science, but long remembered by many a desolated fireside. Certainly nothing can be more open and explicit than the account given by Dr. Peirson, of Salem, of the cases seen by him. In the first nineteen days of January, 1829, he had five consecutive cases of puerperal fever, every patient he attended being attacked, and the three first cases proving fatal. In March of the same year he had two moderate cases, in June, another case, and in July, another, which proved fatal. "Up to this period," he remarks, "I am not informed that a single case had occurred in the practice of any other physician. Since that period I have had no fatal case in my practice, although I have had several dangerous cases. I have attended in all twenty cases of this disease, of which four have been fatal. I am not aware that there has been any other case in the town of distinct puerperal peritonitis, although I am willing to admit my information may be very defective on this point. I have been told of some 'mixed cases,' and 'morbid affections after delivery.'" [Footnote: Remarks on Puerperal Fever, pp. 12 and 13.] In the "Quarterly Summary of the Transactions of the College of Physicians of Philadelphia" [Footnote: For May, June, and July, 1842.] may be found some most extraordinary developments respecting a series of cases occurring in the practice of a member of that body. Dr. Condie called the attention of the Society to the prevalence, at the present time, of puerperal fever of a peculiarly insidious and malignant character. "In the practice of one gentleman extensively engaged as an obstetrician nearly every female he has attended in confinement, during several weeks past, within the above limits" (the southern sections and neighboring districts), "had been attacked by the fever." "An important query presents itself, the doctor observed, in reference to the particular form of fever now prevalent. Is it, namely, capable of being propagated by contagion, and is a physician who has been in attendance upon a case of the disease warranted in continuing, without interruption, his practice as an obstetrician? Dr. C., although not a believer in the contagious character of many of those affections generally supposed to be propagated in this manner, has, nevertheless, become convinced by the facts that have fallen under his notice that the puerperal fever now prevailing is capable of being communicated by contagion. How, otherwise, can be explained the very curious circumstance of the disease in one district being exclusively confined to the practice of a single physician, a Fellow of this College, extensively engaged in obstetrical practice, while no instance of the disease has occurred in the patients under the care of any other accoucheur practising within the same district; scarcely a female that has been delivered for weeks past has escaped an attack?" Dr. Rutter, the practitioner referred to, "observed that, after the occurrence of a number of cases of the disease in his practice, he had left the city and remained absent for a week, but, on returning, no article of clothing he then wore having been used by him before, one of the very first cases of parturition he attended was followed by an attack of the fever and terminated fatally; he cannot readily, therefore, believe in the transmission of the disease from female to female in the person or clothes of the physician." The meeting at which these remarks were made was held on the 3d of May, 1842. In a letter dated December 20, 1842, addressed to Dr. Meigs, and to be found in the "Medical Examiner," [Footnote: For January 21, 1843.] he speaks of "those horrible cases of puerperal fever, some of which you did me the favor to see with me during the past summer," and talks of his experience in the disease, "now numbering nearly seventy cases, all of which have occurred within less than a twelve-month past." And Dr. Meigs asserts, on the same page, "Indeed, I believe that his practice in that department of the profession was greater than that of any other gentleman, which was probably the cause of his seeing a greater number of the cases." This from a professor of midwifery, who some time ago assured a gentleman whom he met in consultation that the night on which they met was the eighteenth in succession that he himself had been summoned from his repose, [Footnote: Medical Examiner for December 10, 1842.] seems hardly satisfactory. I must call the attention of the inquirer most particularly to the Quarterly Report above referred to, and the letters of Dr. Meigs and Dr. Rutter, to be found in the "Medical Examiner." Whatever impression they may produce upon his mind, I trust they will at least convince him that there is some reason for looking into this apparently uninviting subject. At a meeting of the College of Physicians just mentioned Dr. Warrington stated that a few days after assisting at an autopsy of puerperal peritonitis, in which he laded out the contents of the abdominal cavity with his hands, he was called upon to deliver three women in rapid succession. All of these women were attacked with different forms of what is commonly called puerperal fever. Soon after these he saw two other patients, both on the same day, with the same disease. Of these five patients, two died. At the same meeting Dr. West mentioned a fact related to him by Dr. Samuel Jackson, of Northumberland. Seven females, delivered by Dr. Jackson in rapid succession, while practising in Northumberland County, were all attacked with puerperal fever, and five of them died. "Women," he said, "who had expected me to attend upon them, now becoming alarmed, removed out of my reach, and others sent for a physician residing several miles distant. These women, as well as those attended by midwives, all did well; nor did we hear of any deaths in child-bed within a radius of fifty miles, excepting two, and these I afterwards ascertained to have been caused by other diseases." He underwent, as he thought, a thorough purification, and still his next patient was attacked with the disease and died. He was led to suspect that the contagion might have been carried in the gloves which he had worn in attendance upon the previous cases. Two months or more after this he had two other cases. He could find nothing to account for these unless it were the instruments for giving enemata, which had been used in two of the former cases and were employed by these patients. When the first case occurred, he was attending and dressing a limb extensively mortified from erysipelas, and went immediately to the accouchement with his clothes and gloves most thoroughly imbued with its effluvia. And here I may mention that this very Dr. Samael Jackson, of Northumberland, is one of Dr. Dewees's authorities against contagion. The three following statements are now for the first time given to the public. All of the cases referred to occurred within this State, and two of the three series in Boston and its immediate vicinity. I. The first is a series of cases which took place during the last spring in a town at some distance from this neighborhood. A physician of that town, Dr. C, Had the following consecutive cases: No. 1, delivered March 20, died March 24. " 2, " April 9, " April 14. " 3, " " 10, " " 14. " 4, " " 11, " " 18. " 5, " " 27, " May 3. " 6, " " 28, had some symptoms, recovered. " 7, " May 8, had some symptoms, also recovered. These were the only cases attended by this physician during the period referred to, "They were all attended by him until their termination, with the exception of the patient No. 6, who fell into the hands of another physician on the 2d of May." (Dr. C. left town for a few days at this time.) Dr. C. attended cases immediately before and after the above-named periods, none of which, however, presented any peculiar symptoms of the disease. About the 1st of July he attended another patient in a neighboring village, who died two or three days after delivery. The first patient, it is stated, was delivered on the 20th of March. "On the 19th Dr. C. made the autopsy of a man who had died suddenly, sick only forty-eight hours; had oedema of the thigh and gangrene extending from a little above the ankle into the cavity of the abdomen." Dr. C. wounded himself very slightly in the right hand during the autopsy. The hand was quite painful the night following, during his attendance on the patient No. 1. He did not see this patient after the 20th, being confined to the house, and very sick from the wound just mentioned, from this time until the 3d of April. Several cases of erysipelas occurred in the house where the autopsy mentioned above took place, soon after the examination. There were also many cases of erysipelas in town at the time of the fatal puerperal cases which have been mentioned. The nurse who laid out the body of the patient No. 3 was taken on the evening of the same day with sore throat and erysipelas, and died in ten days from the first attack. The nurse who laid out the body of the patient No. 4 was taken on the day following with symptoms like those of this patient, and died in a week, without any external marks of erysipelas. "No other cases of similar character with those of Dr. C. occurred in the practice of any of the physicians in the town or vicinity at the time. Deaths following confinement have occurred in the practice of other physicians during the past year, but they were not cases of puerperal fever. No post-mortem examinations were held in any of these puerperal cases." Some additional statements in this letter are deserving of insertion: "A physician attended a woman in the immediate neighborhood of the cases numbered 2, 3, and 4. This patient was confined the morning of March 1st, and died on the night of Match 7th. It is doubtful whether this should be considered a case of puerperal fever. She had suffered from canker, indigestion, and diarrhoea for a year previous to her delivery. Her complaints were much aggravated for two or three months previous to delivery; she had become greatly emaciated, and weakened to such an extent that it had not been expected that she would long survive her confinement, if indeed she reached that period. Her labor was easy enough; she flowed a good deal, seemed exceedingly prostrated, had ringing in her ears, and other symptoms of exhaustion; the pulse was quick and small. On the second and third day there was some tenderness and tumefaction of the abdomen, which increased somewhat on the fourth and fifth. He had cases in midwifery before and after this, which presented nothing peculiar. It is also mentioned in the same letter that another physician had a case during the last summer and another last fall, both of which recovered. Another gentleman reports a case last December, a second case five weeks, and another three weeks, since. All these recovered, A case also occurred very recently in the practice of a physician in the village where the eighth patient of Dr. C. resides, which proved fatal "This patient had some patches of erysipelas on the legs and arms. The same physician has delivered three cases since, which have all done well. There have been no other cases in this town or its vicinity recently. There have been some few cases of erysipelas." It deserves notice that the partner of Dr. C, who attended the autopsy of the man above mentioned and took an active part in it, who also suffered very slightly from a prick under the thumb-nail received during the examination, had twelve cases of midwifery between March 26th and April 12th, all of which did well, and presented no peculiar symptoms. It should also be stated that during these seventeen days he was in attendance on all the cases of erysipelas in the house where the autopsy had been performed. I owe these facts to the prompt kindness of a gentleman whose intelligence and character are sufficient guaranty for their accuracy. The two following letters were addressed to my friend Dr. Storer by the gentleman in whose practice the cases of puerperal fever occurred. His name renders it unnecessary to refer more particularly to these gentlemen, who on their part have manifested the most perfect freedom and courtesy in affording these accounts of their painful experience. "January 38, 1843. II ... "The time to which you allude was in 1830. The first case was in February, during a very cold time. She was confined the 4th, and died the 12th. Between the 10th and 28th of this month I attended six women in labor, all of whom did well except the last, as also two who were confined March 1st and 5th. Mrs. E., confined February 28th, sickened, and died March 8th. The next day, 9th, I inspected the body, and the night after attended a lady, Mrs. B., who sickened, and died 16th. The 10th, I attended another, Mrs. G., who sickened, but recovered. March 16th I went from Mrs. G.'s room to attend a Mrs. H., who sickened, and died 21st. The 17th, I inspected Mrs. B. On the 19th, I went directly from Mrs. H.'s room to attend another lady, Mrs. G., who also sickened, and died 22d. While Mrs. B. was sick, on 15th, I went directly from her room a few rods, and attended another woman, who was not sick. Up to 20th of this month I wore the same clothes. I now refused to attend any labor, and did not till April 21st, when, having thoroughly cleansed myself, I resumed my practice, and had no more puerperal fever. "The cases were not confined to a narrow space. The two nearest were half a mile from each other, and half that distance from my residence. The others were from two to three miles apart, and nearly that distance from my residence. There were no other cases in their immediate vicinity which came to my knowledge. The general health of all the women was pretty good, and all the labors as good as common, except the first. This woman, in consequence of my not arriving in season, and the child being half-born at some time before I arrived, was very much exposed to the cold at the time of confinement, and afterwards, being confined in a very open, cold room. Of the six cases, you perceive only one recovered. "In the winter of 1817 two of my patients had puerperal fever, one very badly, the other not so badly. Both recovered. One other had swelled leg or phlegmasia dolens, and one or two others did not recover as well as usual. "In the summer of 1835 another disastrous period occurred in my practice. July 1st I attended a lady in labor, who was afterwards quite ill and feverish; but at the time I did not consider her case a decided puerperal fever. On the 8th I attended one who did well. On the 12th, one who was seriously sick. This was also an equivocal case, apparently arising from constipation and irritation of the rectum. These women were ten miles apart and five from my residence. On 15th and 2Oth two who did well. On 25th I attended another. This was a severe labor, and followed by unequivocal puerperal fever, or peritonitis. She recovered. August 2nd and 3rd, in about twenty-four hours, I attended four persons. Two of them did very well; one was attacked with some of the common symptoms, which, however, subsided in a day or two, and the other had decided puerperal fever, but recovered. This woman resided five miles from me. Up to this time I wore the same coat. All my other clothes had frequently been changed. On 6th, I attended two women, one of whom was not sick at all; but the other, Mrs. L., was afterwards taken ill. On 10th, I attended a lady, who did very well. I had previously changed all my clothes, and had no garment on which had been in a puerperal room. On 12th, I was called to Mrs. S., in labor. While she was ill, I left her to visit Mrs. L., one of the ladies who was confined on 6th. Mrs. L. had been more unwell than usual, but I had not considered her case anything more than common till this visit. I had on a surtout at this visit, which, on my return to Mrs. S., I left in another room. Mrs. S. was delivered on 13th with forceps. These women both died of decided puerperal fever. "While I attended these women in their fevers I changed my clothes, and washed my hands in a solution of chloride of lime after each visit. I attended seven women in labor during this period, all of whom recovered without sickness. "In my practice I have had several single cases of puerperal fever, some of whom have died and some have recovered. Until the year 1830 I had no suspicion that the disease could be communicated from one patient to another by a nurse or midwife; but I now think the foregoing facts strongly favor that idea. I was so much convinced of this fact that I adopted the plan before related. "I believe my own health was as good as usual at each of the above periods. I have no recollection to the contrary. "I believe I have answered all your questions. I have been more particular on some points perhaps than necessary; but I thought you could form your own opinion better than to take mine. In 1830 I wrote to Dr. Channing a more particular statement of my cases. If I have not answered your questions sufficiently, perhaps Dr. C. may have my letter to him, and you can find your answer there." [Footnote: In a letter to myself this gentleman also stated," I do not recollect that there was any erysipelas or any other disease particularly prevalent at the time."] "Boston, February 3, 1843. III. "My Dear Sir: I received a note from you last evening requesting me to answer certain questions therein proposed, touching the cases of puerperal fever which came under my observation the past summer. It gives me pleasure to comply with your request, so far as it is in my power so to do, but, owing to the hurry in preparing for a journey, the notes of the cases I had then taken were lost or mislaid. The principal facts, however, are too vivid upon my recollection to be soon forgotten. I think, therefore, that I shall be able to give you all the information you may require. "All the cases that occurred in my practice took place between the 7th of May and the 17th of June, 1842. They were not confined to any particular part of the city. The first two cases were patients residing at the South End, the next was at the extreme North End, one living in Sea Street and the other in Roxbury. The following is the order in which they occurred: "CASE 1.--Mrs.-- was confined on the 7th of May, at 5 o'clock, P. M., after a natural labor of six hours. At 12 o'clock at night, on the 9th (thirty-one hours after confinement), she was taken with severe chill, previous to which she was as comfortable as women usually are under the circumstances. She died on the 10th. "CASE 2.--Mrs.-- was confined on the 10th of June (four weeks after Mrs. C), at 11 A. M., after a natural, but somewhat severe, labor of five hours. At 7 o'clock, on the morning of the 11th, she had a chill. Died on the 12th. "CASE 3.--Mrs.--, confined on the 14th of June, was comfortable until the 18th, when symptoms of puerperal fever were manifest. She died on the 20th. "CASE 4.--Mrs.--, confined June 17th, at 5 o'clock, A. M., was doing well until the morning of the 19th. She died on the evening of the 21st. "CASE 5.--Mrs.--was confined with her FIFTH child on the 17th of June, at 6 o'clock in the evening. This patient had been attacked with puerperal fever, at three of her previous confinements, but the disease yielded to depletion and other remedies without difficulty. This time, I regret to say, I was not so fortunate. She was not attacked, as were the other patients, with a chill, but complained of extreme pain in the abdomen, and tenderness on pressure, almost from the moment of her confinement. In this, as in the other cases, the disease resisted all remedies, and she died in great distress on the 22d of the same month. Owing to the extreme heat of the season and my own indisposition, none of the subjects were examined after death. Dr. Channing, who was in attendance with me on the three last cases, proposed to have a post-mortem examination of the subject of case No. 5, but from some cause which I do not now recollect it was not obtained. "You wish to know whether I wore the same clothes when attending the different cases. I cannot positively say, but I should think I did not, as the weather became warmer after, the first two cases; I therefore think it probable that I made a change of at least a PART of my dress. I have had no other case of puerperal fever in my own practice for three years, save those above related, and I do not remember to have lost a patient before with this disease. While absent, last July, I visited two patients sick with puerperal fever, with a friend of mine in the country. Both of them recovered. "The cases that I have recorded were not confined to any particular constitution or temperament, but it seized upon the strong and the weak, the old and the young--one being over forty years, and the youngest under eighteen years of age... If the disease is of an erysipelatous nature, as many suppose, contagionists may perhaps find some ground for their belief in the fact that, for two weeks previous to my first case of puerperal fever, I had been attending a severe case of erysipelas, and the infection may have been conveyed through me to the patient; but, on the other hand, why is not this the case with other physicians, or with the same physician at all times, for since my return from the country I have had a more inveterate case of erysipelas than ever before, and no difficulty whatever has attended any of my midwifery cases?" I am assured, on unquestionable authority, that "about three years since a gentleman in extensive midwifery business, in a neighboring State, lost in the course of a few weeks eight patients in child-bed, seven of them being undoubted cases of puerperal fever. No other physician of the town lost a single patient of this disease during the same period." And from what I have heard in conversation with some of our most experienced practitioners, I am inclined to think many cases of the kind might be brought to light by extensive inquiry. This long catalogue of melancholy histories assumes a still darker aspect when we remember how kindly nature deals with the parturient female, when she is not immersed in the virulent atmosphere of an impure lying-in hospital, or poisoned in her chamber by the unsuspected breath of contagion. From all causes together not more than four deaths in a thousand births and miscarriages happened in England and Wales during the period embraced by the first Report of the Registrar-General. [Footnote: First Report, p. 105.] In the second Report the mortality was shown to be about five in one thousand. [Footnote: Second Report, p. 73.] In the Dublin Lying-in Hospital, during the seven years of Dr. Collins's mastership, there was one case of puerperal fever to 178 deliveries, or less than six to the thousand, and one death from this disease in 278 cases, or between three and four to the thousand. [Footnote: Collins's Treatise on Midwifery, p. 228, etc.] Yet during this period the disease was endemic in the hospital, and might have gone on to rival the horrors of the pestilence of the Maternite, had not the poison been destroyed by a thorough purification. In private practice, leaving out of view the cases that are to be ascribed to the self-acting system of propagation, it would seem that the disease must be far from common. Mr. White, of Manchester, says: "Out of the whole number of lying-in patients whom I have delivered (and I may safely call it a great one), I have never lost one, nor to the best of my recollection has one been greatly endangered, by the puerperal, miliary, low nervous, putrid malignant, or milk fever." [Footnote: Op. cit., p. 115.] Dr. Joseph Clarke informed Dr. Collins that in the course of FORTY-FIVE years' most extensive practice he lost but FOUR patients from this disease. [Footnote: Op. cit., p.228.] One of the most eminent practitioners of Glasgow who has been engaged in very extensive practice for upwards of a quarter of a century testifies that he never saw more than twelve cases of real puerperal fever. [Footnote: Lancet, May 4, 1833.] I have myself been told by two gentlemen practicing in this city, and having for many years a large midwifery business, that they had neither of them lost a patient from this disease, and by one of them that he had only seen it in consultation with other physicians. In five hundred cases of midwifery, of which Dr. Storer has given an abstract in the first number of this journal, there was only one instance of fatal puerperal peritonitis. In the view of these facts it does appear a singular coincidence that one man or woman should have ten, twenty, thirty, or seventy cases of this rare disease following his or her footsteps with the keenness of a beagle, through the streets and lanes of a crowded city, while the scores that cross the same paths on the same errands know it only by name. It is a series of similar coincidences which has led us to consider the dagger, the musket, and certain innocent-looking white powders as having some little claim to be regarded as dangerous. It is the practical inattention to similar coincidences which has given rise to the unpleasant but often necessary documents called INDICTMENTS, which has sharpened a form of the cephalotome sometimes employed in the case of adults, and adjusted that modification of the fillet which delivers the world of those who happen to be too much in the way while such striking coincidences are taking place. I shall now mention a few instances in which the disease appears to have been conveyed by the process of direct inoculation. Dr. Campbell, of Edinburgh, states that in October, 1821, he assisted at the post-mortem examination of a patient who died with puerperal fever. He carried the pelvic viscera in his pocket to the class-room. The same evening he attended a woman in labor without previously changing his clothes; this patient died. The next morning he delivered a woman with the forceps; she died also, and of many others who were seized with the disease within a few weeks, three shared the same fate in succession. In June, 1823, he assisted some of his pupils at the autopsy of a case of puerperal fever. He was unable to wash his hands with proper care, for want of the necessary accommodations. On getting home he found that two patients required his assistance. He went without further ablution or changing his clothes; both these patients died with puerperal fever. [Footnote: Lond. Med. Gazette, December 10, 1831.] This same Dr. Campbell is one of Dr. Churchill's authorities against contagion. Mr. Roberton says that in one instance within his knowledge a practitioner passed the catheter for a patient with puerperal fever late in the evening; the same night he attended a lady who had the symptoms of the disease on the second day. In another instance a surgeon was called while in the act of inspecting the body of a woman who had died of this fever, to attend a labor; within forty-eight hours this patient was seized with the fever [Footnote: Ibid. for January 1832]. On the 16th of March, 1831, a medical practitioner examined the body of a woman who had died a few days after delivery, from puerperal peritonitis. On the evening of the 17th he delivered a patient, who was seized with puerperal fever on the 19th, and died on the 24th. Between this period and the 6th of April the same practitioner attended two other patients, both of whom were attacked with the same disease and died. [Footnote: London Cyc. of Pract. Med., art., "Fever, Puerperal."] In the autumn of 1829 a physician was present at the examination of a case of puerperal fever, dissected out the organs, and assisted in sewing up the body. He had scarcely reached home when he was summoned to attend a young lady in labor. In sixteen hours she was attacked with the symptoms of puerperal fever, and narrowly escaped with her life. [Footnote: Ibid.] In December, 1830, a midwife, who had attended two fatal cases of puerperal fever at the British Lying-in Hospital, examined a patient who had just been admitted, to ascertain if labor had commenced. This patient remained two days in the expectation that labor would come on, when she returned home and was then suddenly taken in labor and delivered before she could set out for the hospital. She went on favorably for two days, and was then taken with puerperal fever and died in thirty-six hours. [Footnote: Ibid.] A young practitioner, contrary to advice, examined the body of a patient who had died from puerperal fever; there was no epidemic at the time; the case appeared to be purely sporadic. He delivered three other women shortly afterwards; they all died with puerperal fever, the symptoms of which broke out very soon after labor. The patients of his colleague did well, except one, where he assisted to remove some coagula from the uterus; she was attacked in the same manner as those whom he had attended, and died also." The writer in the "British and Foreign Medical Review," from whom I quote this statement,--and who is no other than Dr. Rigby,--adds: "We trust that this fact alone will forever silence such doubts, and stamp the well-merited epithet of 'criminal,' as above quoted, upon such attempts [Footnote: Brit. and For. Medical Review for January, 1842, p. 112.] From the cases given by Mr. Ingleby I select the following: Two gentlemen, after having been engaged in conducting the post- mortem examination of a case of puerperal fever, went in the same dress, each respectively, to a case of midwifery. "The one patient was seized with the rigor about thirty hours afterwards. The other patient was seized with a rigor the third morning after delivery. ONE RECOVERED, ONE DIED." [Footnote: Edin. Med. and Surg. Journal, April 1838.] One of these same gentlemen attended another woman in the same clothes two days after the autopsy referred to. "The rigor did not take place until the evening of the fifth day from the first visit. RESULT FATAL." These cases belonged to a series of seven, the first of which was thought to have originated in a case of erysipelas. "Several cases of a mild character followed the foregoing seven, and their nature being now most unequivocal, my friend declined visiting all midwifery cases for a time, and there was no recurrence of the disease." These cases occurred in 1833. Five of them proved fatal. Mr. Ingleby gives another series of seven cases which occurred to a practitioner in 1836, the first of which was also attributed to his having opened several erysipelatous abscesses a short time previously. I need not refer to the case lately read before this society, in which a physician went, soon after performing an autopsy of a case of puerperal fever, to a woman in labor, who was seized with the same disease and perished. The forfeit of that error has been already paid. At a meeting of the Medical and Chirurgical Society before referred to, Dr. Merriman related an instance occurring in his own practice, which excites a reasonable suspicion that two lives were sacrificed to a still less dangerous experiment. He was at the examination of a case of puerperal fever at two o'clock in the afternoon. HE TOOK CARE NOT TO TOUCH THE BODY. At nine o'clock the same evening he attended a woman in labor; she was so nearly delivered that he had scarcely anything to do. The next morning she had severe rigors, and in forty-eight hours she was a corpse. Her infant had erysipelas and died in two days. [Footnote: Lancet, May 2, 1840.] In connection with the facts which have been stated it seems proper to allude to the dangerous and often fatal effects which have followed from wounds received in the post-mortem examination of patients who have died of puerperal fever. The fact that such wounds are attended with peculiar risk has been long noticed. I find that Chaussier was in the habit of cautioning his students against the danger to which they were exposed in these dissections. [Footnote: Stein, L'Art d'Accoucher, 1794; Dict. des Sciences Medicales, art., "Puerperal."] The head pharmacien of the Hotel Dieu, in his analysis of the fluid effused in puerperal peritonitis, says that practitioners are convinced of its deleterious qualities, and that it is very dangerous to apply it to the denuded skin. [Footnote: Journal de Pharmacie, January 1836.] Sir Benjamin Brodie speaks of it as being well known that the inoculation of lymph or pus from the peritoneum of a puerperal patient is often attended with dangerous and even fatal symptoms. Three cases in confirmation of this statement, two of them fatal, have been reported to this society within a few months. Of about fifty cases of injuries of this kind, of various degrees of severity, which I have collected from different sources, at least twelve were instances of infection from puerperal peritonitis. Some of the others are so stated as to render it probable that they may have been of the same nature. Five other cases were of peritoneal inflammation; three in males. Three were what was called enteritis, in one instance complicated with erysipelas; but it is well known that this term has been often used to signify inflammation of the peritoneum covering the intestines. On the other hand, no case of typhus or typhoid fever is mentioned as giving rise to dangerous consequences, with the exception of the single instance of an undertaker mentioned by Mr. Travers, who seems to have been poisoned by a fluid which exuded from the body. The other accidents were produced by dissection, or some other mode of contact with bodies of patients who had died of various affections. They also differed much in severity, the cases of puerperal origin being among the most formidable and fatal. Now a moment's reflection will show that the number of cases of serious consequences ensuing from the dissection of the bodies of those who had perished of puerperal fever is so vastly disproportioned to the relatively small number of autopsies made in this complaint as compared with typhus or pneumonia (from which last disease not one case of poisoning happened), and still more from all diseases put together, that the conclusion is irresistible that a most fearful morbid poison is often generated in the course of this disease. Whether or not it is sui generis confined to this disease, or produced in some others, as, for instance, erysipelas, I need not stop to inquire. In connection with this may be taken the following statement of Dr. Rigby: "That the discharges from a patient under puerperal fever are in the highest degree contagious we have abundant evidence in the history of lying-in hospitals. The puerperal abscesses are also contagious, and may be communicated to healthy lying-in women by washing with the same sponge; this fact has been repeatedly proved in the Vienna Hospital; but they are equally communicable to women not pregnant; on more than one occasion the women engaged in washing the soiled bed-linen of the General Lying-in Hospital have been attacked with abscesses in the fingers or hands, attended with rapidly spreading inflammation of the cellular tissue."[Footnote: System of Midwifery, p. 292] Now add to all this the undisputed fact that within the walls of lying-in hospitals there is often generated a miasm, palpable as the chlorine used to destroy it, tenacious so as in some cases almost to defy extirpation, deadly in some institutions as the plague; which has killed women in a private hospital of London so fast that they were buried two in one coffin to conceal its horrors; which enabled Tonnelle to record two hundred and twenty- two autopsies at the Maternite of Paris; which has led Dr. Lee to express his deliberate conviction that the loss of life occasioned by these institutions completely defeats the objects of their founders; and out of this train of cumulative evidence, the multiplied groups of cases clustering about individuals, the deadly results of autopsies, the inoculation by fluids from the living patient, the murderous poison of hospitals--does there not result a conclusion that laughs all sophistry to scorn, and renders all argument an insult? I have had occasion to mention some instances in which there was an apparent relation between puerperal fever and erysipelas. The length to which this paper has extended does not allow me to enter into the consideration of this most important subject. I will only say that the evidence appears to me altogether satisfactory that some most fatal series of puerperal fever have been produced by an infection originating in the matter or effluvia of erysipelas. In evidence of some connection between the two diseases, I need not go back to the older authors, as Pouteau or Gordon, but will content myself with giving the following references, with their dates; from which it will be seen that the testimony has been constantly coming before the profession for the last few years: "London Cyclopaedia of Practical Medicine," article "Puerperal Fever," 1833. Mr. Ceeley's Account of the Puerperal Fever at Aylesbury, "Lancet," 1835. Dr. Ramsbotham's Lecture, "London Medical Gazette," 1835. Mr. Yates Ackerly's Letter in the same journal, 1838. Mr. Ingleby on Epidemic Puerperal Fever, "Edinburgh Medical and Surgical Journal," 1838. Mr. Paley's Letter, "London Medical Gazette," 1839. Remarks at the Medical and Chirurgical Society, "Lancet," 1840. Dr. Rigby's "System of Midwifery," 1841. "Nunneley on Erysipelas," a work which contains a large number of references on the subject, 1841. "British and Foreign Quarterly Review," 1842. Dr. S. Jackson, of Northumberland, as already quoted from the Summary of the College of Physicians, 1842. And, lastly, a startling series of cases by Mr. Storrs, of Doncaster, to be found in the "American Journal of the Medical Sciences" for January, 1843. The relation of puerperal fever with other continued fevers would seem to be remote and rarely obvious. Hey refers to two cases of synochus occurring in the Royal Infirmary of Edinburgh, in women who had attended upon puerperal patients. Dr. Collins refers to several instances in which puerperal fever has appeared to originate from a continued proximity to patients suffering with typhus. [Footnote: Treatise on Midwifery, p. 228.] Such occurrences as those just mentioned, though most important to be remembered and guarded against, hardly attract our notice in the midst of the gloomy facts by which they are surrounded. Of these facts, at the risk of fatiguing repetitions, I have summoned a sufficient number, as I believe, to convince the most incredulous that every attempt to disguise the truth which underlies them all is useless. It is true that some of the historians of the disease, especially Hulme, Hull, and Leake, in England; Tonnelle, Duges, and Baudelocque, in France, profess not to have found puerperal fever contagious. At the most they give us mere negative facts, worthless against an extent of evidence which now overlaps the widest range of doubt, and doubles upon itself in the redundancy of superfluous demonstration. Examined in detail, this and much of the show of testimony brought up to stare the daylight of conviction out of countenance, proves to be in a great measure unmeaning and inapplicable, as might be easily shown were it necessary. Nor do I feel the necessity of enforcing the conclusion which arises spontaneously from the facts which have been enumerated by formally citing the opinions of those grave authorities who have for the last half-century been sounding the unwelcome truth it has cost so many lives to establish. "It is to the British practitioner," says Dr. Rigby, "that we are indebted for strongly insisting upon this important and dangerous character of puerperal fever." [Footnote: British and Foreign Med. Rev. for January, 1842.] The names of Gordon, John Clarke, Denman, Burns, Young, [Footnote: Encyc. Britannica, xiii, 467, art., "Medicine."] Hamilton,[Footnote: Outlines of Midwifery, p. 109.] Haighton, [Footnote: Oral Lectures, etc.] Good, [Footnote: Study of Medicine, ii, 195.] Waller, [Footnote: Medical and Physical Journal, July, 1830.] Blundell, Gooch, Ramsbotham, Douglas, [Footnote: Dublin Hospital Reports for 1822.] Lee, Ingleby, Locock, [Footnote: Library of Practical Medicine, I. 373], Abercrombie [Footnote: Researches on Diseases of the Stomach, etc. p. 1841], Alison [Footnote: Library of Practical Medicine, i, 95.], Travers, [Footnote: Further Researches on Constitutional Irritation, p. 128], Rigby, and Watson [Footnote: London Medical Gazette, February, 1842] many of whose writings I have already referred to, may have some influence with those who prefer the weight of authorities to the simple deductions of their own reason from the facts aid before them. A few Continental writers have adopted similar conclusions [Footnote: See British and Foreign Medical Review, vol. iil, p. 525, and vol. iv, p. 517. Also Ed. Med. and Surg. Journal for July 1824, and American Journal of Med. Sciences for January, 1841.] It gives me pleasure to remember that, while the doctrine has been unceremoniously discredited in one of the leading journals [Footnote: PIsid. Med. Journal, vol. xii, p. 364], and made very light of by teachers in two of the principal medical schools of this country, Dr. Channing has for many years inculcated, and enforced by examples, the danger to be apprehended and the precautions to be taken in the disease under consideration. I have no wish to express any harsh feeling with regard to the painful subject which has come before us. If there are any so far excited by the story of these dreadful events that they ask for some word of indignant remonstrance to show that science does not turn the hearts of its followers into ice or stone, let me remind them that such words have been uttered by those who speak with an authority I could not claim [Footnote: Dr. Blundell and Dr. Bigby in the works already cited.] It is as a lesson rather than as a reproach that I call up the memory of these irreparable errors and wrongs. No tongue can tell the heart-breaking calamity they have caused; they have closed the eyes just opened upon a new world of love and happiness; they have bowed the strength of manhood into the dust; they have cast the helplessness of infancy into the stranger's arms, or bequeathed it, with less cruelty, the death of its dying parent. There is no tone deep enough for regret, and no voice loud enough for warning. The woman about to become a mother. or with her new-born infant upon her bosom, should be the object of trembling care and sympathy wherever she bears her tender burden or stretches her aching limbs. The very outcast of the streets has pity upon her sister in degradation when the seal of promised maternity is impressed upon her. The remorseless vengeance of the law, brought down upon its victim by a machinery as sure as destiny, is arrested in its fall at a word which reveals her transient claim for mercy. The solemn prayer of the liturgy singles out her sorrows from the multiplied trials of life, to plead for her in the hour of peril. God forbid that any member of the profession to which she trusts her life, doubly precious at that eventful period, should hazard it negligently, unadvisedly, or selfishly! There may be some among those whom I address who are disposed to ask the question, What course are we to follow in relation to this matter? The facts are before them, and the answer must be left to their own judgment and conscience. If any should care to know my own conclusions, they are the following; and in taking the liberty to state them very freely and broadly, I would ask the inquirer to examine them as freely in the light of the evidence which has been laid before him. 1. A physician holding himself in readiness to attend cases of midwifery should never take any active part in the post-mortem examination of cases of puerperal fever. 2. If a physician is present at such autopsies, he should use thorough ablution, change every article of dress, and allow twenty-four hours or more to elapse before attending to any case of midwifery. It may be well to extend the same caution to cases of simple peritonitis. 3. Similar precautions should be taken after the autopsy or surgical treatment of cases of erysipelas, if the physician is obliged to unite such offices with his obstetrical duties, which is in the highest degree inexpedient. 4. On the occurrence of a single case of puerperal fever In his practice, the physician is bound to consider the next female he attends in labor, unless some weeks at least have elapsed, as in danger of being infected by him, and it is his duty to take every precaution to diminish her risk of disease and death. 5. If within a short period two cases of puerperal fever happen close to each other, in the practice of the same physician, the disease not existing or prevailing in the neighborhood, he would do wisely to relinquish his obstetrical practice for at least one month, and endeavor to free himself by every available means from any noxious influence he may carry about with him. 6. The occurrence of three or more closely connected cases, in the practice of one individual, no others existing in the neighborhood, and no other sufficient cause being alleged for the coincidence, is prima facie evidence that he is the vehicle of contagion. 7. It is the duty of the physician to take every precaution that the disease shall not be introduced by nurses or other assistants, by making proper inquiries concerning them, and giving timely warning of every suspected source of danger. 8. Whatever indulgence may be granted to those who have heretofore been the ignorant causes of so much misery, the time has come when the existence of a private pestilence in the sphere of a single physician should be looked upon, not as a misfortune, but a crime; and in the knowledge of such occurrences the duties of the practitioner to his profession should give way to his paramount obligations to society. ADDITIONAL REFERENCES AND CASES. Fifth Annual Report of the Registrar-General of England, 1843, Appendix. Letter from William Fair, Esq.--Several new series of cases are given in the letter of Mr. Storrs, contained in the appendix to this report. Mr. Storrs suggests precautions similar to those I have laid down, and these precautions are strongly enforced by Mr. Farr, who is, therefore, obnoxious to the same criticisms as myself. Hall and Dexter, in Am. Journal of Med. Sc. for January, 1844.-- Cases of puerperal fever seeming to originate in erysipelas. Elkington, of Birmingham, in Provincial Med. Journal, cited in Am. Journ. Med. Sc. for April, 1844.--Six cases in less than a fortnight, seeming to originate in a case of erysipelas. West's Reports, in Brit. and For. Med. Review for October, 1845, and January, 1847.--Affection of the arm, resembling malignant pustule, after removing the placenta of a patient who died from puerperal fever. Reference to cases at Wurzburg, as proving contagion, and to Keiller's cases in the Monthly Journal for February, 1846, as showing connection of puerperal fever and erysipelas. Kneeland.--Contagiousness of Puerperal Fever. Am. Jour. Med. Sc., January, 1846. Also, Connection between Puerperal Fever Epidemic Erysipelas. Ibid., April, 1846. Robert Storrs.-Contagious Effects of Puerperal Fever on the Male Subject; or on Persons not Child-bearing. (From Provincial Med. and Surg. Journal.) Am. Jour. Med. Sc., January, 1846. Numerous cases. See also Dr. Reid's case in same journal for April, 1846. Routh's paper in Proc. of Royal Med. Chir. Soc., Am. Jour. Med. Sc., April, 1849, also in B. and F. Med. Chir. Review, April, 1850. Hill, of Leuchars.--A Series of Cases Illustrating the Contagious Nature of Erysipelas and Puerperal Fever, and their Intimate Pathological Connection. (From Monthly Journal of Med. Sc.) Am. Jour. Med. Sc., July, 1850. Skoda on the Causes of Puerperal Fever. (Peritonitis in rabbits, from inoculation with different morbid secretions.) Am. Jour. Med. Sc., October, 1850. Arneth.--Paper read before the National Academy of Medicine. Annales d'Hygiene, Tome LXV. 2e Partie. ("Means of Disinfection proposed by M. Semmelweis." Semmelweiss.) Lotions of chloride of lime and use of nail-brush before admission to lying-in wards, Alleged sudden and great decrease of mortality from puerperal fever. Cause of disease attributed to inoculation with cadaveric matters.) See also Routh's paper, mentioned above. Moir.--Remarks at a meeting of the Edinburgh Medico-chirurgical Society. Refers to cases of Dr. Kellie, of Leith. Sixteen in succession, all fatal. Also to several instances of individual pupils having had a succession of cases in various quarters of the town, while others, practising as extensively in the same localities, had none. Also to several special cases not mentioned elsewhere. Am. Jour. Med. Sc. for October, 1851. (From New Monthly Journal of Med. Science.) Simpson.--Observations at a Meeting of the Edinburgh Obstetrical Society. (An "eminent gentleman," according to Dr. Meigs, whose "name is as well known in America as in (his) native land," Obstetrics, Phil., 1852, pp. 368, 375.) The student is referred to this paper for a valuable resume of many of the facts, and the necessary inferences, relating to this subject. Also for another series of cases, Mr. Sidey's, five or six in rapid succession. Dr. Simpson attended the dissection of two of Dr. Sidey's cases, and freely handled the diseased parts. His next four child-bed patients were affected with puerperal fever, and it was the first time he had seen it in practice. As Dr. Simpson is a gentleman (Dr. Meigs, as above), and as "a gentleman's hands are clean" (Dr. Meigs' sixth letter), it follows that a gentleman with clean hands may carry the disease. Am. Jour. Med. Sc., October, 1851. Peddie.--The five or six cases of Dr. Sidey, followed by the four of Dr. Simpson, did not end the series. A practitioner in Leith having examined in Dr. Simpson's house, a portion of the uterus obtained from one of the patients, had immediately afterwards three fatal cases of puerperal fever. Dr. Peddie referred to two distinct series of consecutive cases in his own practice. He had since taken precautions, and not met with any such cases. Am. Jour. Med October, 1851. Copland.--Considers it proved that puerperal fever may be propagated by the hands and the clothes, or either, of a third person, the bed-clothes or body-clothes of a patient. Mentions a new series of cases, one of which he saw, with the practitioner who had attended them. She was THE SIXTH he had had within a few days. ALL DIED. Dr. Copland insisted that contagion had caused these cases; advised precautionary measures, and the practitioner had no other cases for a considerable time. Considers it CRIMINAL, after the evidence adduced,--which be could have quadrupled,--and the weight of authority brought forward, for a practitioner to be the medium of transmitting contagion and death to his patients. Dr. Copland lays down rules similar to those suggested by myself, and is therefore entitled to the same epithet for so doing. Medical Dictionary, New York, 1853. Article, Puerperal States and Diseases. If there is any appetite for facts so craving as to be yet unappeased,--lassata, necdum satiata,--more can be obtained. Dr. Hodge remarks that "the frequency and importance of this singular circumstance that the disease is occasionally more prevalent with one practitioner than another, has been exceedingly overrated." More than thirty strings of cases, more than two hundred and fifty sufferers from puerperal fever, more than one hundred and thirty deaths, appear as the results of a sparing estimate of such among the facts I have gleaned as could be numerically valued. These facts constitute, we may take it for granted, but a small fraction of those that have actually occurred. The number of them might be greater, but "'t is enough, 't will serve," in Mercutio's modest phrase, so far as frequency is concerned. For a just estimate of the importance of the singular circumstance, it might be proper to consult the languid survivors, the widowed husbands, and the motherless children, as well as "the unfortunate accoucheur." ON THE ANTISEPTIC PRINCIPLE OF THE PRACTICE OF SURGERY BY JOSEPH LISTER INTRODUCTORY NOTE Joseph Lister was born at Upton, Essex, England, in 1827, and received Aw general education at the University of London. After graduation he studied medicine in London and Edinburgh, and became lecturer in surgery at the University in the latter city. Later he was professor of surgery at Glasgow, at Edinburgh, and at King's College Hospital, London, and surgeon to Queen Victoria. He was made a baronet in 1883; retired from teaching in 1893; and was raised to the peerage in 1897, with the title of Baron Lister. Even before the work of Pasteur on fermentation and putrefaction, Lister had been convinced of the importance of scrupulous cleanliness and the usefulness of deodorants in the operating room; and when, through Pasteur's researches, he realised that the formation of PUS was due to bacteria, he proceeded to develop his antiseptic surgical methods. The immediate success of the new treatment led to its general adoption, with results of such beneficence as to make it rank as one of the great discoveries of the age. ON THE ANTISEPTIC PRINCIPLE OF THE PRACTICE OF SURGERY (1867) In the course of an extended investigation into the nature of inflammation, and the healthy and morbid conditions of the blood in relation to it, I arrived several years ago at the conclusion that the essential cause of suppuration in wounds is decomposition brought about by the influence of the atmosphere upon blood or serum retained within them, and, in the case of contused wounds, upon portions of tissue destroyed by the violence of the injury. To prevent the occurrence of suppuration with all its attendant risks was an object manifestly desirable, but till lately apparently unattainable, since it seemed hopeless to attempt to exclude the oxygen which was universally regarded as the agent by which putrefaction was effected. But when it had been shown by the researches of Pasteur that the septic properties of the atmosphere depended not on the oxygen, or any gaseous constituent, but on minute organisms suspended in it, which owed their energy to their vitality, it occurred to me that decomposition in the injured part might be avoided without excluding the air, by applying as a dressing some material capable of destroying the life of the floating particles. Upon this principle I have based a practice of which I will now attempt to give a short account. The material which I have employed is carbolic or phenic acid, a volatile organic compound, which appears to exercise a peculiarly destructive influence upon low forms of life, and hence is the most powerful antiseptic with which we are at present acquainted. The first class of cases to which I applied it was that of compound fractures, in which the effects of decomposition in the injured part were especially striking and pernicious. The results have been such as to establish conclusively the great principle that all local inflammatory mischief and general febrile disturbances which follow severe injuries are due to the irritating and poisonous influence of decomposing blood or sloughs. For these evils are entirely avoided by the antiseptic treatment, so that limbs which would otherwise be unhesitatingly condemned to amputation may be retained, with confidence of the best results. In conducting the treatment, the first object must be the destruction of any septic germs which may have been introduced into the wounds, either at the moment of the accident or during the time which has since elapsed. This is done by introducing the acid of full strength into all accessible recesses of the wound by means of a piece of rag held in dressing forceps and dipped into the liquid. [Footnote: The addition of a few drops of water to a considerable quantity of the acid, induces it to assume permanently the liquid form.] This I did not venture to do in the earlier cases; but experience has shown that the compound which carbolic acid forms with the blood, and also any portions of tissue killed by its caustic action, including even parts of the bone, are disposed of by absorption and organisation, provided they are afterwards kept from decomposing. We are thus enabled to employ the antiseptic treatment efficiently at a period after the occurrence of the injury at which it would otherwise probably fail. Thus I have now under my care, in Glasgow Infirmary, a boy who was admitted with compound fracture of the leg as late as eight and one-half hours after the accident, in whom, nevertheless, all local and constitutional disturbance was avoided by means of carbolic acid, and the bones were soundly united five weeks after his admission. The next object to be kept in view is to guard effectually against the spreading of decomposition into the wound along the stream of blood and serum which oozes out during the first few days after the accident, when the acid originally applied has been washed out or dissipated by absorption and evaporation. This part of the treatment has been greatly improved during the past few weeks. The method which I have hitherto published (see Lancet for Mar. 16th, 23rd, 30th, and April 27th of the present year) consisted in the application of a piece of lint dipped in the acid, overlapping the sound skin to some extent and covered with a tin cap, which was daily raised in order to touch the surface of the lint with the antiseptic. This method certainly succeeded well with wounds of moderate size; and indeed I may say that in all the many cases of this kind which have been so treated by myself or my house-surgeons, not a single failure has occurred. When, however, the wound is very large, the flow of blood and serum is so profuse, especially during the first twenty-four hours, that the antiseptic application cannot prevent the spread of decomposition into the interior unless it overlaps the sound skin for a very considerable distance, and this was inadmissible by the method described above, on account of the extensive sloughing of the surface of the cutis which it would involve. This difficulty has, however, been overcome by employing a paste composed of common whiting (carbonate of lime), mixed with a solution of one part of carbolic acid in four parts of boiled linseed oil so as to form a firm putty. This application contains the acid in too dilute a form to excoriate the skin, which it may be made to cover to any extent that may be thought desirable, while its substance serves as a reservoir of the antiseptic material. So long as any discharge continues, the paste should be changed daily, and, in order to prevent the chance of mischief occurring during the process, a piece of rag dipped in the solution of carbolic acid in oil is put on next the skin, and maintained there permanently, care being taken to avoid raising it along with the putty. This rag is always kept in an antiseptic condition from contact with the paste above it, and destroys any germs which may fall upon it during the short time that should alone be allowed to pass in the changing of the dressing. The putty should be in a layer about a quarter of an inch thick, and may be advantageously applied rolled out between two pieces of thin calico, which maintain it in the form of a continuous sheet, which may be wrapped in a moment round the whole circumference of a limb if this be thought desirable, while the putty is prevented by the calico from sticking to the rag which is next the skin.[Footnote: In order to prevent evaporation of the acid, which passes readily through any organic tissue, such as oiled silk or gutta percha, it is well to cover the paste with a sheet of block tin. or tinfoil strengthened with adhesive plaster. The tin sheet lead used for lining tea chests will also answer the purpose, and may be obtained from any wholesale grocer.] When all discharge has ceased, the use of the paste is discontinued, but the original rag is left adhering to the skin till healing by scabbing is supposed to be complete. I have at present in the hospital a man with severe compound fracture of both bones of the left leg, caused by direct violence, who, after the cessation of the sanibus discharge under the use of the paste, without a drop of pus appearing, has been treated for the last two weeks exactly as if the fracture was a simple one. During this time the rag, adhering by means of a crust of inspissated blood collected beneath it, has continued perfectly dry, and it will be left untouched till the usual period for removing the splints in a simple fracture, when we may fairly expect to find a sound cicatrix beneath it. We cannot, however, always calculate on so perfect a result as this. More or less pus may appear after the lapse of the first week, and the larger the wound, the more likely this is to happen. And here I would desire earnestly to enforce the necessity of persevering with the antiseptic application in spite of the appearance of suppuration, so long as other symptoms are favorable. The surgeon is extremely apt to suppose that any suppuration is an indication that the antiseptic treatment has failed, and that poulticing or water dressing should be resorted to. But such a course would in many cases sacrifice a limb or a life. I cannot, however, expect my professional brethren to follow my advice blindly in such a matter, and therefore I feel it necessary to place before them, as shortly as I can, some pathological principles intimately connected, not only with the point we are immediately considering, but with the whole subject of this paper. If a perfectly healthy granulating sore be well washed and covered with a plate of clean metal, such as block tin, fitting its surface pretty accurately, and overlapping the surrounding skin an inch or so in every direction and retained in position by adhesive plaster and a bandage, it will be found, on removing it after twenty-four or forty-eight hours, that little or nothing that can be called pus is present, merely a little transparent fluid, while at the same time there is an entire absence of the unpleasant odour invariably perceived when water dressing is changed. Here the clean metallic surface presents no recesses like those of porous lint for the septic germs to develope in, the fluid exuding from the surface of the granulations has flowed away undecomposed, and the result is the absence of suppuration. This simple experiment illustrates the important fact that granulations have no inherent tendency to form pus, but do so only when subjected to preternatural stimulus. Further, it shows that the mere contact of a foreign body does not of itself stimulate granulations to suppurate; whereas the presence of decomposing organic matter does. These truths are even more strikingly exemplified by the fact that I have elsewhere recorded (Lancet, March 23rd, 1867), that a piece of dead bone free from decomposition may not only fail to induce the granulations around it to suppurate, but may actually be absorbed by them; whereas a bit of dead bone soaked with putrid pus infallibly induces suppuration in its vicinity. Another instructive experiment is, to dress a granulating sore with some of the putty above described, overlapping the sound skin extensively; when we find, in the course of twenty-four hours, that pus has been produced by the sore, although the application has been perfectly antiseptic; and, indeed, the larger the amount of carbolic acid in the paste, the greater is the quantity of pus formed, provided we avoid such a proportion as would act as a caustic. The carbolic acid, though it prevents decomposition, induces suppuration--obviously by acting as a chemical stimulus; and we may safely infer that putrescent organic materials (which we know to be chemically acrid) operate in the same way. In so far, then, carbolic acid and decomposing substances are alike; viz., that they induce suppuration by chemical stimulation, as distinguished from what may be termed simple inflammatory suppuration, such as that in which ordinary abscesses originate--where the pus appears to be formed in consequence of an excited action of the nerves, independently of any other stimulus. There is, however, this enormous difference between the effects of carbolic acid and those of decomposition; viz., that carbolic acid stimulates only the surface to which it is at first applied, and every drop of discharge that forms weakens the stimulant by diluting it; but decomposition is a self-propagating and self-aggravating poison, and, if it occur at the surface of a severely injured limb, it will spread into all its recesses so far as any extravasated blood or shreds of dead tissue may extend, and lying in those recesses, it will become from hour to hour more acrid, till it requires the energy of a caustic sufficient to destroy the vitality of any tissues naturally weak from inferior vascular supply, or weakened by the injury they sustained in the accident. Hence it is easy to understand how, when a wound is very large, the crust beneath the rag may prove here and there insufficient to protect the raw surface from the stimulating influence of the carbolic acid in the putty; and the result will be first the conversion of the tissues so acted on into granulations, and subsequently the formation of more or less pus. This, however, will be merely superficial, and will not interfere with the absorption and organisation of extravasated blood or dead tissues in the interior. But, on the other hand, should decomposition set in before the internal parts have become securely consolidated, the most disastrous results may ensue. I left behind me in Glasgow a boy, thirteen years of age, who, between three and four weeks previously, met with a most severe injury to the left arm, which he got entangled in a machine at a fair. There was a wound six inches long and three inches broad, and the skin was very extensively undermined beyond its limits, while the soft parts were generally so much lacerated that a pair of dressing forceps introduced at the wound and pushed directly inwards appeared beneath the skin at the opposite aspect of the limb. From this wound several tags of muscle were hanging, and among them was One consisting of about three inches of the triceps in almost Its entire thickness; while the lower fragment of the bone, which was broken high up, was protruding four inches and a half, stripped of muscle, the skin being tucked in under it. Without the assistance of the antiseptic treatment, I should certainly have thought of nothing else but amputation at the shoulder-joint; but, as the radial pulse could be felt and the fingers had sensation, I did not hesitate to try to save the limb and adopted the plan of treatment above described, wrapping the arm from the shoulder to below the elbow in the antiseptic application, the whole interior of the wound, together with the protruding bone, having previously been freely treated with strong carbolic acid. About the tenth day, the discharge, which up to that time had been only sanious and serous, showed a slight admixture of slimy pus; and this increased till (a few days before I left) it amounted to about three drachms in twenty-four hours. But the boy continued as he had been after the second day, free from unfavorable symptoms, with pulse, tongue, appetite, and sleep natural and strength increasing, while the limb remained as it had been from the first, free from swelling, redness, or pain. I. therefore, persevered with the antiseptic dressing; and, before I left, the discharge was already somewhat less, while the bone was becoming firm. I think it likely that, in that boy's case, I should have found merely a superficial sore had I taken off all the dressings at the end of the three weeks; though, considering the extent of the injury, I thought it prudent to let the month expire before disturbing the rag next the skin. But I feel sure that, if I had resorted to ordinary dressing when the pus first appeared, the progress of the case would have been exceedingly different. The next class of cases to which I have applied the antiseptic treatment is that of abscesses. Here also the results have been extremely satisfactory, and in beautiful harmony with the pathological principles indicated above. The pyogenic membrane, like the granulations of a sore, which it resembles in nature, forms pus, not from any inherent disposition to do so, but only because it is subjected to some preternatural stimulation. In an ordinary abscess, whether acute or chronic, before it is opened the stimulus which maintains the suppuration is derived from the presence of pus pent up within the cavity. When a free opening is made in the ordinary way, this stimulus is got rid of, but the atmosphere gaining access to the contents, the potent stimulus of decomposition comes into operation, and pus is generated in greater abundance than before. But when the evacuation is effected on the antiseptic principle, the pyogenic membrane, freed from the influence of the former stimulus without the substitution of a new one, ceases to suppurate (like the granulations of a sore under metallic dressing), furnishing merely a trifling amount of clear serum, and, whether the opening be dependent or not, rapidly contracts and coalesces. At the same time any constitutional symptoms previously occasioned by the accumulation of the matter are got rid of without the slightest risk of the irritative fever or hectic hitherto so justly dreaded in dealing with large abscesses. In order that the treatment may be satisfactory, the abscess must be seen before it is opened. Then, except in very rare and peculiar cases [Footnote: As an instance of one of these exceptional cases, I may mention that of an abscess in the vicinity of the colon, and afterwords proved by post-mortem examination to have once communicated with it. Here the pus was extremely offensive when evacuated, and exhibited vibros under the microscope.], there are no septic organisms in the contents, so that it is needless to introduce carbolic acid into the interior. Indeed, such a procedure would be objectionable, as it would stimulate the pyogenic membrane to unnecessary suppuration. All that is requisite is to guard against the introduction of living atmospheric germs from without, at the same time that free opportunity is afforded for the escape of the discharge from within. I have so lately given elsewhere a detailed account of the method by which this is effected (Lancet, July 27th, 1867), that I shall not enter into it at present further than to say that the means employed are the same as those described above for the superficial dressing of compound fractures; viz., a piece of rag dipped into the solution of carbolic add in oil to serve as an antiseptic curtain, under cover of which the abscess is evacuated by free incision, and the antiseptic paste to guard against decomposition occurring in the stream of pus that flows out beneath it; the dressing being changed daily until the sinus is closed. The most remarkable results of this practice in a pathological point of view have been afforded by cases where the formation of pus depended on disease of bone. Here the abscesses, instead of forming exceptions to the general class in the obstinacy of the suppuration, have resembled the rest in yielding in a few days only a trifling discharge, and frequently the production of pus has ceased from the moment of the evacuation of the original contents. Hence it appears that caries, when no longer labouring as heretofore under the irritation of decomposing matter, ceases to be an opprobrium of surgery, and recovers like other inflammatory affections. In the publication before alluded to, I have mentioned the case of a middle-aged man with a psoas abscess depending in diseased bone, in whom the sinus finally closed after months of patient perseverance with the antiseptic treatment. Since that article was written I have had another instance of abscess equally gratifying, but the differing in the circumstance that the disease and the recovery were more rapid in their course. The patient was a blacksmith, who had suffered four and a half months before I saw him from symptoms of ulceration of cartilage in the left elbow. These had latterly increased in severity so as to deprive him entirely of his night's rest and of appetite. I found the region of the elbow greatly swollen, and on careful examination found a fluctuating point at the outer aspect of the articulation. I opened it on the antiseptic principle, the incision evidently penetrating to the joint, giving exit to a few drachms of pus. The medical gentleman under whose care he was (Dr. Macgregor, of Glasgow) supervised the daily dressing with the carbolic acid paste till the patient went to spend two or three weeks at the coast, when his wife was entrusted with it. Just two months after I opened the abscess, he called to show me the limb, stating that the discharge had been, for at least two weeks, as little as it was then, a trifling moisture upon the paste, such as might be accounted for by the little sore caused by the incision. On applying a probe guarded with an antiseptic rag, I found that the sinus was soundly closed, while the limb was free from swelling or tenderness; and, although he had not attempted to exercise it much, the joint could already be moved through a considerable angle. Here the antiseptic principle had effected the restoration of a joint, which, on any other known system of treatment, must have been excised. Ordinary contused wounds are, of course, amenable to the same treatment as compound fractures, which are a complicated variety of them. I will content myself with mentioning a single instance of this class of cases. In April last, a volunteer was discharging a rifle when it burst, and blew back the thumb with its metacarpal bone, so that it could be bent back as on a hinge at the trapezial joint, which had evidently been opened, while all the soft parts between the metacarpal bones of the thumb and forefinger were torn through. I need not insist before my present audience on the ugly character of such an injury. My house- surgeon, Mr. Hector Cameron, applied carbolic acid to the whole raw surface, and completed the dressing as if for compound fracture. The hand remained free from pain, redness or swelling, and with the exception of a shallow groove, all the wound consolidated without a drop of matter, so that if it had been a clean cut, it would have been regarded as a good example of primary union. The small granulating surface soon healed, and at present a linear cicatrix alone tells of the injury he has sustained, while his thumb has all its movements and his hand a fine grasp. If the severest forms of contused and lacerated wounds heal thus kindly under the antiseptic treatment, it is obvious that its application to simple incised wounds must be merely a matter of detail. I have devoted a good deal of attention to this class, but I have not as yet pleased myself altogether with any of the methods I have employed. I am, however, prepared to go so far as to say that a solution of carbolic acid in twenty parts of water, while a mild and cleanly application, may be relied on for destroying any septic germs that may fall upon the wound during the performance of an operation; and also that, for preventing the subsequent introduction of others, the paste above described, applied as for compound fractures, gives excellent results. Thus I have had a case of strangulated inguinal hernia in which it was necessary to take away half a pound of thickened omentum, heal without any deep-seated suppuration or any tenderness of the sac or any fever; and amputations, including one immediately below the knee, have remained absolutely free from constitutional symptoms. Further, I have found that when the antiseptic treatment is efficiently conducted, ligatures may be safely cut short and left to be disposed of by absorption or otherwise. Should this particular branch of the subject yield all that it promises, should it turn out on further trial that when the knot is applied on the antiseptic principle, we may calculate as securely as if it were absent on the occurrence of healing without any deep- seated suppuration, the deligation of main arteries in their continuity will be deprived of the two dangers that now attend it, viz., those of secondary haemorrhage and an unhealthy state of the wound. Further, it seems not unlikely that the present objection to tying an artery in the immediate vicinity of a large branch may be done away with; and that even the innominate, which has lately been the subject of an ingenious experiment by one of the Dublin surgeons, on account of its well-known fatality under the ligature for secondary haemorrhage, may cease to have this unhappy character when the tissues in the vicinity of the thread, instead of becoming softened through the influence of an irritating decomposing substance, are left at liberty to consolidate firmly near an unoffending though foreign body. It would carry me far beyond the limited time which, by the rules of the Association, is alone at my disposal, were I to enter into the various applications of the antiseptic principle in the several special departments of surgery. There is, however, one point more that I cannot but advert to, viz., the influence of this mode of treatment upon the general healthiness of an hospital. Previously to its introduction the two large wards in which most of my cases of accident and of operation are treated were among the unhealthiest in the whole surgical division of the Glasgow Royal Infirmary, in consequence apparently of those wards being unfavorably placed with reference to the supply of fresh air; and I have felt ashamed when recording the results of my practice, to have so often to allude to hospital gangrene or pyaemia. It was interesting, though melancholy, to observe that whenever all or nearly all the beds contained cases with open sores, these grievous complications were pretty sure to show themselves; so that I came to welcome simple fractures, though in themselves of little interest either for myself or the students, because their presence diminished the proportion of open sores among the patients. But since the antiseptic treatment has been brought into full operation, and wounds and abscesses no longer poison the atmosphere with putrid exhalations, my wards, though in other respects under precisely the same circumstances as before, have completely changed their character; so that during the last nine months not a single instance of pysemia, hospital gangrene, or erysipelas has occurred in them. As there appears to be no doubt regarding the cause of this change, the importance of the fact can hardly be exaggerated. THE PHYSIOLOGICAL THEORY OF FERMENTATION BY LOUIS PASTEUR TRANSLATED BY F. FAULKNER AND D. C. ROBB AND REVISED THE GERM THEORY AND ITS APPLICATIONS TO MEDICINE AND SURGERY BY MM. PASTEUR, JOURBERT, AND CHAMBERLAND TRANSLATED BY H. C. ERNST, M. D. PROFESSOR OF BACTERIOLOGY IN THE HARVARD MEDICAL SCHOOL ON THE EXTENSION OF THE GERM THEORY TO THE ETIOLOGY OF CERTAIN COMMON DISEASES BY LOUIS PASTEUR TRANSLATED BY H. C. ERNST, M. D. INTRODUCTORY NOTE Louis Pasteur was born at Dole, Jura, France, December 27, 1822, and died near Saint-Cloud, September 28, 1895. His interest in science, and especially in chemistry, developed early, and by the time he was twenty-six he was professor of the physical sciences at Dijon. The most important academic positions held by him later were those as professor of chemistry at Strasburg, 1849; dean of the Faculty of Sciences at Lille, 1854; science director of the Ecole Normale Superieure, Paris, 1857; professor of geology, physics, and chemistry at the Ecole des Beaux Arts; Professor of chemistry at the Sorbonne, 1867. After 1875 he carried on his researches at the Pasteur Institute. He was a member of the Institute, and received many honors from learned societies at home and abroad. In respect of the number and importance, practical as well as scientific, of his discoveries, Pasteur has hardly a rival in the history of science. He may be regarded as the founder of modern stereo-chemistry; and his discovery that living organisms are the cause of fermentation is the basis of the whole modern germ- theory of disease and of the antiseptic method of treatment. His investigations of the diseases of beer and wine; of pebrine, a disease affecting silk-worms; of anthrax, and of fowl cholera, were of immense commercial importance and led to conclusions which have revolutionised physiology, pathology, and therapeutics. By his studies in the culture of bacteria of attenuated virulence he extended widely the practise of inoculation with a milder form of various diseases, with a view to producing immunity. The following papers present some of the most important of his contributions, and exemplify his extraordinary powers of lucid exposition and argument. TO THE MEMORY OF MY FATHER FORMERLY A SOLDIER UNDER THE FIRST EMPIRE CHEVALIER OF THE LEGION OF HONOR The longer I live, the better I understand the kindness of thy heart and the high quality of thy mind. The efforts which I have devoted to these Studies, as well as those which preceded them, are the fruit of thy counsel and example. Desiring to honor these filial remembrances, I dedicate this work to thy memory. L. PASTEUR. AUTHOR'S PREFACE Our misfortunes inspired me with the idea of these researches. I undertook them immediately after the war of 1870, and have since continued them without interruption, with the determination of perfecting them, and thereby benefiting a branch of industry wherein we are undoubtedly surpassed by Germany. I am convinced that I have found a precise, practical solution of the arduous problem which I proposed to myself--that of a process of manufacture, independent of season and locality, which should obviate the necessity of having recourse to the costly methods of cooling employed in existing processes, and at the same time secure the preservation of its products for any length of time. These new studies are based on the same principles which guided me in my researches on wine, vinegar, and the silkworm disease-- principles, the applications of which are practically unlimited. The etiology of contagious diseases may, perhaps, receive from them an unexpected light. I need not hazard any prediction concerning the advantages likely to accrue to the brewing industry from the adoption of such a process of brewing as my study of the subject has enabled me to devise, and from an application of the novel facts upon which this process is founded. Time is the best appraiser of scientific work, and I am not unaware that an industrial discovery rarely produces all its fruit in the hands of its first inventor. I began my researches at Clermont-Ferrand, in the laboratory, and with the help, of my friend M. Duclaux, professor of chemistry at the Faculty of Sciences of that town. I continued them in Paris, and afterwards at the great brewery of Tourtel Brothers, of Tantonville, which is admitted to be the first in France. I heartily thank these gentlemen for their extreme kindness. I owe also a public tribute of gratitude to M. Kuhn, a skillful brewer of Chamalieres, near Clermont-Ferrand, as well as to M. Velten of Marseilles, and to MM. de Tassigny, of Reims, who have placed at my disposal their establishments and their products, with the most praiseworthy eagerness. L. PASTEUR. Paris, June 1, 1879. THE PHYSIOLOGICAL THEORY OF FERMENTATION I. ON THE RELATIONS EXISTING BETWEEN OXYGEN AND YEAST It is characteristic of science to reduce incessantly the number of unexplained phenomena. It is observed, for instance, that fleshy fruits are not liable to fermentation so long as their epidermis remains uninjured. On the other hand, they ferment very readily when they are piled up in heaps more or less open, and immersed in their saccharine juice. The mass becomes heated and swells; carbonic acid gas is disengaged, and the sugar disappears and is replaced by alcohol. Now, as to the question of the origin of these spontaneous phenomena, so remarkable in character as well as usefulness for man's service, modern knowledge has taught us that fermentation is the consequence of a development of vegetable cells the germs of which do not exist in the saccharine juices within fruits; that many varieties of these cellular plants exist, each giving rise to its own particular fermentation. The principal products of these various fermentations, although resembling each other in their nature, differ in their relative proportions and in the accessory substances that accompany them, a fact which alone is sufficient to account for wide differences in the quality and commercial value of alcoholic beverages. Now that the discovery of ferments and their living nature, and our knowledge of their origin, may have solved the mystery of the spontaneous appearance of fermentations in natural saccharine juices, we may ask whether we must still regard the reactions that occur in these fermentations as phenomena inexplicable by the ordinary laws of chemistry. We can readily see that fermentations occupy a special place in the series of chemical and biological phenomena. What gives to fermentations certain exceptional characters of which we are only now beginning to suspect the causes, is the mode of life in the minute plants designated under the generic name of ferments, a mode of life which is essentially different from that in other vegetables, and from which result phenomena equally exceptional throughout the whole range of the chemistry of living beings. The least reflection will suffice to convince us that the alcoholic ferments must possess the faculty of vegetating and performing their functions out of contact with air. Let us consider, for instance, the method of vintage practised in the Jura. The bunches are laid at the foot of the vine in a large tub, and the grapes there stripped from them. When the grapes, some of which are uninjured, others bruised, and all moistened by the juice issuing from the latter, fill the tub--where they form what is called the vintage--they are conveyed in barrels to large vessels fixed in cellars of a considerable depth. These vessels are not filled to more than three-quarters of their capacity. Fermentation soon takes place in them, and the carbonic acid gas finds escape through the bunghole, the diameter of which, in the case of the largest vessels, is not more than ten or twelve centimetres (about four inches). The wine is not drawn off before the end of two or three months. In this way it seems highly probable that the yeast which produces the wine under such conditions must have developed, to a great extent at least, out of contact with oxygen. No doubt oxygen is not entirely absent from the first; nay, its limited presence is even a necessity to the manifestation of the phenomena which follow. The grapes are stripped from the bunch in contact with air, and the must which drops from the wounded fruit takes a little of this gas into solution. This small quantity of air so introduced into the must, at the commencement of operations, plays a most indispensable part, it being from the presence of this that the spores of ferments which are spread over the surface of the grapes and the woody part of the bunches derive the power of starting their vital phenomena [Footnote: It has been marked in practice that fermentation is facilitated by leaving the grapes on the bunches. The reason of this has not yet been discovered. Still we have no doubt that it may be attributed, principally, to the fact that the interatices between the grapes, and the spaces between the bunch leaves throughout, considerably increase the volume of air placed at the service of the germs of ferment.]. This air, however, especially when the grapes have been stripped from the bunches, is in such small proportion, and that which is in contact with the liquid mass is so promptly expelled by the carbonic acid gas, which is evolved as soon as a little yeast has formed, that it will readily be admitted that most of the yeast is produced apart from the influence of oxygen, whether free or in solution. We shall revert to this fact, which is of great importance. At present we are only concerned in pointing out that, from the mere knowledge of the practices of certain localities, we are induced to believe that the cells of yeast, after they have developed from their spores, continue to live and multiply without the intervention of oxygen, and that the alcoholic ferments have a mode of life which is probably quite exceptional, since it is not generally met with in other species, vegetable or animal. Another equally exceptional characteristic of yeast and fermentation in general consists in the small proportion which the yeast that forms bears to the sugar that decomposes. In all other known beings the weight of nutritive matter assimilated corresponds with the weight of food used up, any difference that may exist being comparatively small. The life of yeast is entirely different. For a certain weight of yeast formed, we may have ten times, twenty times, a hundred times as much sugar, or even more decomposed, as we shall experimentally prove by-and- bye; that is to say, that whilst the proportion varies in a precise manner, according to conditions which we shall have occasion to specify, it is also greatly out of proportion to the weight of the yeast. We repeat, the life of no other being, under its normal physiological conditions, can show anything similar. The alcoholic ferments, therefore, present themselves to us as plants which possess at least two singular properties: they can live without air, that is without oxygen, and they can cause decomposition to an amount which, though variable, yet, as estimated by weight of product formed, is out of all proportion to the weight of their own substance. These are facts of so great importance, and so intimately connected with the theory of fermentation, that it is indispensable to endeavour to establish them experimentally, with all the exactness of which they will admit. The question before us is whether yeast is in reality an anaerobian [Footnote: Capable of living without free oxygen--a term invented by Pasteur.--En.] plant, and what quantities of sugar it may cause to ferment, under the various conditions under which we cause it to act. The following experiments were undertaken to solve this double problem:--We took a double-necked flask, of three litres (five pints) capacity, one of the tubes being curved and forming an escape for the gas; the other one, on the right hand side (Fig. 1), being furnished with a glass tap. We filled this flask with pure yeast water, sweetened with 5 per cent, of sugar candy, the flask being so full that there was not the least trace of air remaining above the tap or in the escape tube; this artificial wort had, however, been itself aerated. The curved tube was plunged in a porcelain vessel full of mercury, resting on a firm support. In the small cylindrical funnel above the tap, the capacity of which was from 10 cc. to 15 cc. (about half a fluid ounce) we caused to ferment, at a temperature of 20 degrees or 25 degrees C. (about 75 degrees F.), five or six cubic centimetres of the saccharine liquid, by means of a trace of yeast, which multiplied rapidly, causing fermentation, and forming a slight deposit of yeast at the bottom of the funnel above the tap. We then opened the tap, and some of the liquid in the funnel entered the flask, carrying with it the small deposit of yeast, which was sufficient to impregnate the saccharine liquid contained in the flask. In this manner it is possible to introduce as small a quantity of yeast as we wish, a quantity the weight of which, we may say, is hardly appreciable. The yeast sown multiplies rapidly and produces fermentation, the carbonic gas from which is expelled into the mercury. In less than twelve days all the sugar had disappeared, and the fermentation had finished. There was a sensible deposit of yeast adhering to the sides of the flask; collected and dried it weighed 2.25 grammes (34 grains). It is evident that in this experiment the total amount of yeast formed, if it required oxygen to enable it to live, could not have absorbed, at most, more than the volume which was originally held in solution in the saccharine liquid, when that was exposed to the air before being introduced into the flask. [Illustration with caption: Fig. 1] Some exact experiments conducted by M. Raulin in our laboratory have established the fact that saccharine worts, like water, soon become saturated when shaken briskly with an excess of air, and also that they always take into solution a little less air than saturated pure water contains under the same conditions of temperature and pressure. At a temperature of 25 degrees C. (77 degrees F.), therefore, if we adopt the coefficient of the solubility of oxygen in water given in Bunsen's tables, we find that 1 litre (1 3/4 pints) of water saturated with air contains 5.5 cc. (0.3 cubic inch) of oxygen. The three litres of yeast- water in the flask, supposing it to have been saturated, contains less than 16.5 cc. (1 cubic inch) of oxygen, or, in weight, less than 23 milligrammes (0.35 grains). This was the maximum amount of oxygen, supposing the greatest possible quantity to have been absorbed, that was required by the yeast formed in the fermentation of 150 grammes (4.8 Troy ounces) of sugar. We shall better understand the significance of this result later on. Let us repeat the foregoing experiment, but under altered conditions. Let us fill, as before, our flask with sweetened yeast-water, but let this first be boiled, so as to expel all the air it contains. To effect this we arrange our apparatus as represented in the accompanying sketch. (Fig 2.) We place our flask, A, on a tripod above a gas flame, and in place of the vessel of mercury substitute a porcelain dish, under which we can put a gas flame, and Which contains some fermentable, saccharine liquid, similar to that with which the flask is filled. We boil the liquid in the flask and that in the basin simultaneously, and then let them cool down together, so that as the liquid in the flask cools some of the liquid is sucked from the basin into the flask. From a trial experiment which we conducted, determining the quantity of oxygen that remained in solution in the liquid after cooling, according to M. Schutzenberger's valuable method, by means of hydrosulphite of soda [Footnote: NaHSO2, now called sodium hyposulphite.--D.C.R.], we found that the three litres in the flask, treated as we have described, contained less than one milligramme (0.015 grain) of oxygen. At the same time we conducted another experiment, by way of comparison (Fig. 3). We took a flask, B, of larger capacity than the former one, which we filled about half with the same volume as before of a saccharine liquid of identically the same composition. This liquid had been previously freed from alterative germs by boiling. In the funnel surmounting A, we put a few cubic centimetres of saccharine liquid in a state of fermentation, and when this small quantity of liquid was in full fermentation, and the yeast in it was young and vigorous, we opened the tap, closing it again immediately, so that a little of the liquid and yeast still remained in the funnel. By this means we caused the liquid in A to ferment. We also impregnated the liquid in B with some yeast taken from the funnel of A. We then replaced the porcelain dish in which the curved escape tube of A had been plunged, by a vessel filled with mercury. The following is a description of two of these comparative fermentations and the results they gave. [Illustration with caption: Fig 2] [Illustration with caption: Fig. 3] The fermentable liquid was composed of yeast-water sweetened with 5 per cent, of sugar--candy; the ferment employed was sacchormyces pastorianus. The impregnation took place on January 20th. The flasks were placed in an oven at 25 degrees (77 degrees F.). FLASK A, WITHOUT AIR. January 21st.--Fermentation commenced; a little frothy liquid issued from the escape tube and covered the mercury. The following days, fermentation was active. Examining the yeast mixed with the froth that was expelled into the mercury by the evolution of carbonic acid gas, we find that it was very fine, young, and actively budding. February 3rd.--Fermentation still continued, showing itself by a number of little bubbles rising from the bottom of the liquid, which had settled bright. The yeast was at the bottom in the form of a deposit. February 7th.--Fermentation still continued, but very languidly. February 9th.--A very languid fermentation still went on, discernible in little bubbles rising from the bottom of the flask. FLASK B, WITH AIR. January 21st.--A sensible development of yeast. The following days, fermentation was active, and there was an abundant froth on the surface of the liquid. February 1st.--All symptoms of fermentation had ceased. As the fermentation in A would have continued a long time, being so very languid, and as that in B had been finished for several days, we brought to a close our two experiments on February 9th. To do this we poured off the liquids in A and B, collecting the yeasts on tared filters. Filtration was an easy matter, more especially in the case of A. Examining the yeasts under the microscope, immediately after decantation, we found that both of them remained very pure. The yeast in A was in little clusters, the globules of which were collected together, and appeared by their well-defined borders to be ready for an easy revival in contact with air. As might have been expected, the liquid in flask B did not contain the least trace of sugar; that in the flask A still contained some, as was evident from the non-completion of fermentation, but not more than 4.6 grammes (71 grains). Now, as each flask originally contained three litres of liquid holding in solution 5 per cent of sugar, it follows that 150 grammes (2,310 grains) of sugar had fermented in the flask B, and 145.4 grammes (2,239.2 grains) in the flask A. The weights of yeast after drying at 100 degrees C. (212 degrees F.) were-- For the flask B, with air. ... ..1,970 grammes (30.4 grains). For the flask A, without air ... 1,368 grammes [Footnote: This appears to be a misprint for 1.638 grammes=25.3 grains.--D. C. R.]. The proportions were 1 of yeast to 76 of fermented sugar in the first case, and 1 of yeast to 89 of fermented sugar in the second. From these facts the following consequences may be deduced: 1. The fermentable liquid (flask B), which since it had been in contact with air, necessarily held air in solution, although not to the point of saturation, inasmuch as it had been once boiled to free it from all foreign germs, furnished a weight of yeast sensibly greater than that yielded by the liquid which contained no air at all (flask A) or, at least, which could only have contained an exceedingly minute quantity. 2. This same slightly aerated fermentable liquid fermented much more rapidly than the other. In eight or ten days it contained no more sugar; while the other, after twenty days, still contained an appreciable quantity. Is this last fact to be explained by the greater quantity of yeast formed in B? By no means. At first, when the air has access to the liquid, much yeast is formed and little sugar disappears, as we shall prove immediately; nevertheless the yeast formed in contact with the air is more active than the other. Fermentation is correlative first to the development of the globules, and then to the continued life of those globules once formed. The more oxygen these last globules have at their disposal during their formation, the more vigorous, transparent, and turgescent, and, as a consequence of this last quality, the more active they are in decomposing sugar. We shall hereafter revert to these facts. 3. In the airless flask the proportion of yeast to sugar was 1/59; it was only 1/79 in the flask which had air at first. The proportion that the weight of yeast bears to the weight of the sugar is, therefore, variable, and this variation depends, to a certain extent, upon the presence of air and the possibility of oxygen being absorbed by the yeast. We shall presently show that yeast possesses the power of absorbing that gas and emitting carbonic acid, like ordinary fungi, that even oxygen may be reckoned amongst the number of food-stuffs that may be assimilated by this plant, and that this fixation of oxygen in yeast, as well as the oxidations resulting from it, have the most marked effect on the life of yeast, on the multiplication of its cells, and on their activity as ferments acting upon sugar, whether immediately or afterwards, apart from supplies of oxygen or air. In the preceding experiment, conducted without the presence of air, there is one circumstance particularly worthy of notice. This experiment succeeds, that is to say, the yeast sown in the medium deprived of oxygen develops, only when this yeast is in a state of great vigour. We have already explained the meaning of this last expression. But we wish now to call attention to a very evident fact in connection with this point. We impregnate a fermentable liquid; yeast develops and fermentation appears. This lasts for several days and then ceases. Let us suppose that, from the day when fermentation first appears in the production of a minute froth, which gradually increases until it whitens the surface of the liquid, we take, every twenty-four hours, or at longer intervals, a trace of the yeast deposited on the bottom of the vessel and use it for starting fresh fermentations. Conducting these fermentations all under precisely the same conditions of temperature, character and volume of liquid, let us continue this for a prolonged time, even after the original fermentation is finished. We shall have no difficulty in seeing that the first signs of action in each of our series of second fermentations appear always later and later in proportion to the length of time that has elapsed from the commencement of the original fermentation. In other words, the time necessary for the development of the germs and the production of that amount of yeast sufficient to cause the first appearance of fermentation varies with the state of the impregnating cells, and is longer in proportion as the cells are further removed from the period of their formation. It is essential, in experiments of this kind, that the quantities of yeast successively taken should be as nearly as possible equal in weight or volume, since, celeris paribus, fermentations manifest themselves more quickly the larger the quantity of yeast employed in impregnation. If we compare under the microscope the appearance and character of the successive quantities of yeast taken, we shall see plainly that the structure of the cells undergoes a progressive change. The first sample which we take, quite at the beginning of the original fermentation, generally gives us cells rather larger than those later on, and possessing a remarkable tenderness. Their walls are exceedingly thin, the consistency and softness of their protoplasm is akin to fluidity, and their granular contents appear in the form of scarcely visible spots. The borders of the cells soon become more marked, a proof that their walls undergo a thickening; their protoplasm also becomes denser, and the granulations more distinct. Cells of the same organ, in the states of infancy and old age, should not differ more than the cells of which we are speaking, taken in their extreme states. The progressive changes in the cells, after they have acquired their normal form and volume, clearly demonstrate the existence of a chemical work of a remarkable intensity, during which their weight increases, although in volume they undergo no sensible change, a fact that we have often characterized as "the continued life of cells already formed." We may call this work a process of maturation on the part of the cells, almost the same that we see going on in the case of adult beings in general, which continue to live for a long time, even after they have become incapable of reproduction, and long after their volume has become permanently fixed. This being so, it is evident, we repeat, that, to multiply in a fermentable medium, quite out of contact with oxygen, the cells of yeast must be extremely young, full of life and health, and still under the influence of the vital activity which they owe to the free oxygen which has served to form them, and which they have perhaps stored up for a time. When older, they reproduce themselves with much difficulty when deprived of air, and gradually become more languid; and if they do multiply, it is in strange and monstrous forms. A little older still, they remain absolutely inert in a medium deprived of free oxygen. This is not because they are dead; for in general they may be revived in a marvellous manner in the same liquid if it has been first aerated before they are sown. It would not surprise us to learn that at this point certain preconceived ideas suggest themselves to the mind of an attentive reader on the subject of the causes that may serve to account for such strange phenomena in the life of these beings which our ignorance hides under the expressions of YOUTH and AGE; this, however, is a subject which we cannot pause to consider here. At this point we must observe--for it is a matter of great importance--that in the operations of the brewer there is always a time when the yeasts are in this state of vigorous youth of which we have been speaking, acquired under the influence of free oxygen, since all the worts and the yeasts of commerce are necessarily manipulated in contact with air, and so impregnated more or less with oxygen. The yeast immediately seizes upon this gas and acquires a state of freshness and activity, which permits it to live afterwards out of contact with air, and to act as a ferment. Thus, in ordinary brewery practice, we find the yeast already formed in abundance even before the earliest external signs of fermentation have made their appearance. In this first phase of its existence, yeast lives chiefly like an ordinary fungus. From the same circumstances it is clear that the brewer's fermentations may, speaking quite strictly, last for an indefinite time, in consequence of the unceasing supply of fresh wort, and from the fact, moreover, that the exterior air is constantly being introduced during the work, and that the air contained in the fresh worts keeps up the vital activity of the yeast, as the act of breathing keeps up the vigour and life of cells in all living beings. If the air could not renew itself in any way, the vital activity which the cells originally received, under its influence, would become more and more exhausted, and the fermentation eventually come to an end. We may recount one of the results obtained in other experiments similar to the last, in which, however, we employed yeast which was still older than that used for our experiment with flask A (Fig. 2), and moreover took still greater precautions to prevent the presence of air. Instead of leaving the flask, as well as the dish, to cool slowly, after having expelled all air by boiling, we permitted the liquid in the dish to continue boiling whilst the flask was being cooled by artificial means; the end of the escape tube was then taken out of the still boiling dish and plunged into the mercury trough. In impregnating the liquid, instead of employing the contents of the small cylindrical funnel whilst still in a state of fermentation, we waited until this was finished. Under these conditions, fermentation was still going on in our flask, after a lapse of three months. We stopped it and found that 0.255 gramme (3.9 grains) of yeast had been formed, and that 45 grammes (693 grains) of sugar had fermented, the ratio between the weights of yeast and sugar being thus 0.255 divided by 45 = 1 divided by 176. In this experiment the yeast developed with much difficulty, by reason of the conditions to which it had been subjected. In appearance the cells varied much, some were to be found large, elongated, and of tubular aspect, some seemed very old and were extremely granular, whilst others were more transparent. All of them might be considered abnormal cells. In such experiments we encounter another difficulty. If the yeast sown in the non-aerated fermentable liquid is in the least degree impure, especially if we use sweetened yeast-water, we may be sure that alcoholic fermentation will soon cease, if, indeed, it ever commences, and that accessory fermentations will go on. The vibrios of butyric fermentation, for instance, will propagate with remarkable facility under these circumstances. Clearly then, the purity of the yeast at the moment of impregnation, and the purity of the liquid in the funnel, are conditions indispensable to success. To secure the latter of these conditions, we close the funnel, as shown in FIG. 2, by means of a cork pierced with two holes, through one of which a short tube passes, to which a short length of india-rubber tubing provided with a glass stopper is attached; through the other hole a thin curved tube is passed. Thus fitted, the funnel can answer the same purposes as our double-necked flasks. A few cubic centimetres of sweetened yeast-water are put in it and boiled, so that the steam may destroy any germs adhering to the sides; and when cold the liquid is impregnated by means of a trace of pure yeast, introduced through the glass- stoppered tube. If these precautions are neglected, it is scarcely possible to secure a successful fermentation in our flasks, because the yeast sown is immediately held in check by a development of anaerobian vibrios. For greater security, we may add to the fermentable liquid, at the moment when it is prepared, a very small quantity of tartaric acid, which will prevent the development of butyric vibrios. [Illustration with caption: Fig. 4.] The variation of the ratio between the weight of the yeast and that of the sugar decomposed by it now claims special attention. Side by side with the experiments which we have just described, we conducted a third lot by means of the flask C (Fig. 4), holding 4.7 litres (8 1/2 pints), and fitted up like the usual two-necked flasks, with the object of freeing the fermentable liquid from foreign germs, by boiling it to begin with, so that we might carry on our work under conditions of purity. The volume of yeast-water (containing 5 per cent. of sugar) was only 200 cc. (7 fl. oz.), and consequently, taking into account the capacity of the flask, It formed but a very thin layer at the bottom. On the day after impregnation the deposit of yeast was already considerable, and forty-eight hours afterwards the fermentation was completed. On the third day we collected the yeast after having analyzed the gas contained in the flask. This analysis was easily accomplished by placing the flask in a hot-water bath, whilst the end of the curved tube was plunged under a cylinder of mercury. The gas contained 41.4 per cent. of carbonic acid, and, after the absorption, the remaining air contained:-- Oxygen . ... . ... . ... . ... . ... . ... . ... ... 19.7 Nitrogen . ... . ... . ... . ... . ... . ... . ... . 80.3 100.0 Taking into consideration the volume of this flask, this shows a minimum of 50 cc. (3.05 cub. in.) of oxygen to have been absorbed by the yeast. The liquid contained no more sugar, and the weight of the yeast, dried at a temperature of 100 degrees C (212 degrees F.), was 0.44 grammes. The ratio between the weights of yeast and sugar is 0.44/10=1/22.7 [Footnote: 200 cc. of liquid were used, which, as containing 3 per cent., had in solution 10 grammes of sugar.--D.C.R.]. On this occasion, where we had increased the quantity of oxygen held in solution, so as to yield itself for assimilation at the beginning and during the earlier developments of the yeast, we found instead of the previous ratio of 1/76 that of 1/23. [Illustration with caption: Fig. 5] The next experiment was to increase the proportion of oxygen to a still greater extent, by rendering the diffusion of gas a more easy matter than in a flask, the air in which is in a state of perfect quiescence. Such a state of matters hinders the supply of oxygen, inasmuch as the carbonic acid, as soon as it is liberated, at once forms an immovable layer on the surface of the liquid, and so separates off the oxygen. To effect the purpose of our present experiment, we used flat basins having glass bottoms and low sides, also of glass, in which the depth of the liquid is not more than a few millimetres (less than 1/4 inch) (Fig. 5). The following is one of our experiments so conducted:--On April 16th, 1860, we sowed a trace of beer yeast ("high" yeast) in 200 cc. (7 fl. oz.) of a saccharine liquid containing 1.720 grammes (26.2 grains) of sugar-candy. From April 18th our yeast was in good condition and well developed. We collected it, after having added to the liquid a few drops of concentrated sulphuric acid, with the object of checking the fermentation to a great extent, and facilitating filtration. The sugar remaining in the filtered liquid, determined by Fehling's solution, showed that 1.04 grammes (16 grains) of sugar had disappeared. The weight of the yeast, dried at 100 degrees C. (212 degrees F.), was 0.127 gramme (2 grains), which gives us the ratio between the weight of the yeast and that of the fermented sugar 0.123/1.04=1/8.1, which is considerably higher than the preceding ones. We may still further increase this ratio by making our estimation as soon as possible after the impregnation, or the addition of the ferment. It will be readily understood why yeast, which is composed of cells that bud and subsequently detach themselves from one another, soon forms a deposit at the bottom of the vessels. In consequence of this habit of growth, the cells constantly covering each other prevents the lower layers from having access to the oxygen held in solution in the liquid, which is absorbed by the upper ones. Hence, these which are covered and deprived of this gas act on the sugar without deriving any vital benefit from the oxygen--a circumstance which must tend to diminish the ratio of which we are speaking. Once more repeating the preceding experiment, but stopping it as soon as we think that the weight of yeast formed may be determined by the balance (we find that this may be done twenty-four hours after impregnation with an inappreciable quantity of yeast), in this case the ratio between the weights of yeast and sugar is gr/024 yeast/0 gr. 09 sugar=1/4. This is the highest ratio we have been able to obtain. Under these conditions the fermentation of sugar is extremely languid: the ratio obtained is very nearly the same that ordinary fungoid growths would give. The carbonic acid evolved is principally formed by the decompositions which result from the assimilation of atmospheric oxygen. The yeast, therefore, lives and performs its functions after the manner of ordinary fungi: so far it is no longer a ferment, so to say; moreover, we might expect to find it to cease to be a ferment at all if we could only surround each cell separately with all the air that it required. This is what the preceding phenomena teach us; we shall have occasion to compare them later on with others which relate to the vital action exercised on yeast by the sugar of milk. We may here be permitted to make a digression. In his work on fermentations, which M. Schutzenberger has recently published, the author criticises the deductions that we have drawn from the preceding experiments, and combats the explanation which we have given of the phenomena of fermentation. [Footnote: International Science Series, vol. xx, pp. 179-182. London, 1876.--D. C. R.] It is an easy matter to show the weak point of M. Schutzenberger's reasoning. We determined the power of the ferment by the relation of the weight of sugar decomposed to the weight of the yeast produced. M. Schutzenberger asserts that in doing this we lay down a doubtful hypothesis, and he thinks that this power, which he terms FERMENTATIVE ENERGY, may be estimated more correctly by the quantity of sugar decomposed by the unit-weight of yeast in unit-time; moreover, since our experiments show that yeast is very vigorous when it has a sufficient supply of oxygen, and that, in such a case, it can decompose much sugar in a little time, M. Schutzenberger concludes that it must then have great power as a ferment, even greater than when it performs its functions without the aid of air, since under this condition it decomposes sugar very slowly. In short, he is disposed to draw from our observations the very opposite conclusion to that which we arrived at. M, Schutzenberger has failed to notice that the power of a ferment is independent of the time during which it performs its functions. We placed a trace of yeast in one litre of saccharine wort; it propagated, and all the sugar was decomposed. Now, whether the chemical action involved in this decomposition of sugar had required for its completion one day, or one month, or one year, such a factor was of no more importance in this matter than the mechanical labour required to raise a ton of materials from the ground to the top of a house would be affected by the fact that it had taken twelve hours instead of one. The notion of time has nothing to do with the definition of work. M. Schutzenberger has not perceived that in introducing the consideration of time into the definition of the power of a ferment, he must introduce at the same time, that of the vital activity of the cells which is independent of their character as a ferment. Apart from the consideration of the relation existing between the weight of fermentable substance decomposed and that of ferment produced, there is no occasion to speak of fermentations or of ferments. The phenomena of fermentation and of ferments have been placed apart from others, precisely because, in certain chemical actions, that ratio has been out of proportion; but the time that these phenomena require for their accomplishment has nothing to do with either their existence proper, or with their power. The cells of a ferment may, under some circumstances, require eight days for revival and propagation, whilst, under other conditions, only a few hours are necessary; so that, if we introduce the notion of time into our estimate of their power of decomposition, we may be led to conclude that in the first case that power was entirely wanting, and that in the second case it was considerable, although all the time we are dealing with the same organism--the identical ferment. M. Schutzenberger is astonished that fermentation can take place in the presence of free oxygen, if, as we suppose, the decomposition of the sugar is the consequence of the nutrition of the yeast, at the expense of the combined oxygen, which yields itself to the ferment. At all events, he argues, fermentation ought to be slower in the presence of free oxygen. But why should it be slower? We have proved that in the presence of oxygen the vital activity of the cells increases, so that, as far as rapidity of action is concerned, its power cannot be diminished. It might, nevertheless, be weakened as a ferment, and this is precisely what happens. Free oxygen imparts to the yeast a vital activity, but at the same time impairs its power as yeast--qua yeast, inasmuch as under this condition it approaches the state in which it can carry on its vital processes after the manner of an ordinary fungus; the mode of life, that is, in which the ratio between the weight of sugar decomposed and the weight of the new cells produced will be the same as holds generally among organisms which are not ferments. In short, varying our form of expression a little, we may conclude with perfect truth, from the sum total of observed facts, that the yeast which lives in the presence of oxygen and can assimilate as much of that gas as is necessary to its perfect nutrition, ceases absolutely to be a ferment at all. Nevertheless, yeast formed under these conditions and subsequently brought into the presence of sugar, OUT OF THE INFLUENCE OF AIR, would decompose more IN A GIVEN TIME than in any other of its states. The reason is that yeast which has formed in contact with air, having the maximum of free oxygen that it can assimilate is fresher and possessed of greater vital activity than that which has been formed without air or with an insufficiency of air. M. Schutzenberger would associate this activity with the notion of time in estimating the power of the ferment; but he forgets to notice that yeast can only manifest this maximum of energy under a radical change of its life conditions; by having no more air at its disposal and breathing no more free oxygen. In other words, when its respiratory power becomes null, its fermentative power is at its greatest. M. Schutzenberger asserts exactly the opposite (p. 151 of his work-- Paris, 1875) [Footnote: Page 182, English edition], and so gratuitously places himself in opposition to facts. In presence of abundant air supply, yeast vegetates with extraordinary activity. We see this in the weight of new yeast, comparatively large, that may be formed in the course of a few hours. The microscope still more clearly shows this activity in the rapidity of budding, and the fresh and active appearance of all the cells. Fig. 6 represents the yeast of our last experiment at the moment when we stopped the fermentation. Nothing has been taken from imagination, all the groups have been faithfully sketched as they were. [Footnote: This figure is on a scale of 300 diameters, most of the figures in this work being of 400 diameters]. [Illustration with caption: Fig. 6] In passing it is of interest to note how promptly the preceding results were turned to good account practically. In well-managed distilleries, the custom of aerating the wort and the juices to render them more adapted to fermentation, has been introduced. The molasses mixed with water, is permitted to run in thin threads through the air at the moment when the yeast is added. Manufactories have been erected in which the manufacture of yeast is almost exclusively carried on. The saccharine worts, after the addition of yeast, are left to themselves, in contact with air, in shallow vats of large superficial area, realizing thus on an immense scale the conditions of the experiments which we undertook in 1861, and which we have already described in determining the rapid and easy multiplication of yeast in contact with air. The next experiment was to determine the volume of oxygen absorbed by a known quantity of yeast, the yeast living in contact with air, and under such conditions that the absorption of air was comparatively easy and abundant. [Illustration with caption: Fig. 7] With this object we repeated the experiment that we performed with the large-bottomed flask (Fig. 4), employing a vessel shaped like Fig. B (Fig. 7), which is, in point of fact, the flask A with its neck drawn out and closed in a flame, after the introduction of a thin layer of some saccharine juice impregnated with a trace of pure yeast. The following are the data and results of an experiment of this kind. We employed 60 cc. (about 2 fluid ounces) of yeast-water, sweetened with two percent. of sugar and impregnated with a trace of yeast. After having subjected our vessel to a temperature of 25 degrees C. (77 degrees F.) in an oven for fifteen hours, the drawn-out point was brought under an inverted jar filled with mercury and the point broken off. A portion of the gas escaped and was collected in the jar. For 25 cc. of this gas we found, after absorption by potash 20.6, and after absorption by pyrogallic acid, 17.3. Taking into account the volume which remained free in the flask, which held 315 cc., there was a total absorption of 14.5 cc. (0.83 cub. in.) of oxygen. [Footnote: It may be useful for the non-scientific reader to put it thus: that the 25 cc. which escaped, being a fair sample of the whole gas in the flask, and containing (1) 25-20.6=4.4 cc., absorbed by potash and therefore due to carbonic acid, and (2) 20.6-17.3=3.3 cc., absorbed by pyrogallate, and therefore due to oxygen, and the remaining 17.3 cc. being nitrogen, the whole gas in the flask, which has a capacity of 312 cc., will contain oxygen in the above portion and therefore its amount may be determined provided we know the total gas in the flask before opening. On the other hand we know that air normally contains approximately, 1-5 its volume of oxygen, the rest being nitrogen, so that, by ascertaining the diminution of the proportion in the flask, we can find how many cubic centimeters have been absorbed by the yeast. The author, however, has not given all the data necessary for accurate calculation.--D.C.R.] The weight of the yeast, in a state of dryness, was 0.035 gramme. It follows that in the production of 35 milligrammes (0.524 grain) of yeast there was an absorption of 14 or 15 cc. (about 7/8 cub. in.) of oxygen, even supposing that the yeast was formed entirely under the influence of that gas: this is equivalent to not less than 414 cc. for 1 gramme of yeast (or about 33 cubic inches for every 20 grains). [Footnote: This number is probably too small; it is scarcely possible that the increase of weight in the yeast, even under the exceptional conditions of the experiment described, was not to some extent at least due to oxidation apart from free oxygen, inasmuch as some of the cells were covered by others. The increased weight of the yeast is always due to the action of two distant modes of vital energy-- activity, namely, in presence and activity in absence of air. We might endeavor to shorten the duration of the experiment still further, in which case we would still more assimilate the life of the yeast to that of ordinary moulds.] Such is the large volume of oxygen necessary for the development of one gramme of yeast when the plant can assimilate this gas after the manner of an ordinary fungus. Let us now return to the first experiment described in the paragraph on page 292 in which a flask of three litres capacity was filled with fermentable liquid, which, when caused to ferment, yielded 2.25 grammes of yeast, under circumstances where it could not obtain a greater supply of free oxygen than 16.5 cc. (about one cubic inch). According to what we have just stated, if this 2.25 grammes (34 grains) of yeast had not been able to live without oxygen, in other words, if the original cells had been unable to multiply otherwise than by absorbing free oxygen, the amount of that gas required could not have been less than 2.25 X 4l4 cc., that is, 931.5 cc. (56.85 cubic inches). The greater part of the 2.25 grammes, therefore, had evidently been produced as the growth of an anaerobian plant. Ordinary fungi likewise require large quantities of oxygen for their development, as we may readily prove by cultivating any mould in a closed vessel full of air, and then taking the weight of plant formed and measuring the volume of oxygen absorbed. To do this, we take a flask of the shape shown in Fig. 8, capable of holding about 300 cc. (10 1/2 fluid ounces), and containing a liquid adapted to the life of moulds. We boil this liquid, and seal the drawn-out point after the steam has expelled the air wholly or in part; we then open the flask in a garden or in a room. Should a fungus-spore enter the flask, as will invariably be the case in a certain number of flasks out of several used in the experiment, except under special circumstances, it will develop there and gradually absorb all the oxygen contained in the air of the flask. Measuring the volume of this air, and weighing, after drying, the amount of plant formed, we find that for a certain quantity of oxygen absorbed we have a certain weight of mycelium, or of mycelium together with its organs of fructification. In an experiment of this kind, in which the plant was weighed a year after its development, we found for 0.008 gramme (0.123 gram) of MYCELIUM, dried at 100 degrees C. (212 degrees F.), an absorption that amounted to not less than 43 cc. (2.5 cubic inches) of oxygen at 25 degrees. These numbers, however, must vary sensibly with the nature of the mould employed, and also with the greater or less activity of its development, because the phenomena is complicated by the presence of accessory oxidations, such as we find in the case of mycoderma vini and aceti, to which cause the large absorption of oxygen in our last experiment may doubtless be attributed. [Footnote: In these experiments, in which the moulds remain for a long time in contact with a saccharine wort out of contact with oxygen--the oxygen being promptly absorbed by the vital action of the plant (see our Memoire sur les Generations dites Spontanees, p. 54. note)--there is no doubt that an appreciable quantity of alcohol is formed because the plant does not immediately lose vital activity after the absorption of oxygen. A 300 cc. (10-oz.) flask, containing 100 cc. of must, after the air in it had been expelled by boiling, was open and immediately re-closed on August 15th, 1873. A fungoid growth--a unique one, of greenish-grey colour--developed from spontaneous impregnation, and decolourized the liquid, which originally was of a yellowish- brown. Some large crystals, sparkling like diamonds, of neutral tartrate of lime, were precipitated, about a year afterwards, long after the death of the plant, we examined this liquid. It contained 0.3 gramme (4.6 grains) of alcohol, and 0.053 gramme (0.8 grain) of vegetable matter, dried at 100 degrees C. (212 degrees F.). We ascertained that the spores of the fungus were dead at the moment when the flask was opened. When sown, they did not develop in the least degree.] The conclusions to be drawn from the whole of the preceding facts can scarcely admit of doubt. As for ourselves, we have no hesitation in finding them the foundation of the true theory of fermentation. In the experiments which we have described, fermentation by yeast, that is to say, by the type of ferments properly so called, is presented to us, in a word, as the direct consequence of the processes of nutrition, assimilation and life, when these are carried on without the agency of free oxygen. The heat required in the accomplishment of that work must necessarily have been borrowed from the decomposition of the fermentable matter, that is from the saccharine substance which, like other unstable substances, liberates heat in undergoing decomposition. Fermentation by means of yeast appears, therefore, to be essentially connected with the property possessed by this minute cellular plant of performing its respiratory functions, somehow or other, with oxygen existing combined in sugar. Its fermentative power--which power must not be confounded with the fermentative activity or the intensity of decomposition in a given time--varies considerably between two limits, fixed by the greatest and least possible access to free oxygen which the plant has in the process of nutrition. If we supply it with a sufficient quantity of free oxygen for the necessities of its life, nutrition, and respiratory combustions, in other words, if we cause it to live after the manner of a mould, properly so called, it ceases to be a ferment, that is, the ratio between the weight of the plant developed and that of the sugar decomposed, which forms its principal food, is similar in amount to that in the case of fungi. [Footnote: We find in M. Raulin's note that "the minimum ratio between the weight of sugar and the weight of organized matter, that is, the weight of fungoid growth which it helps to form, may be expressed as 10/3.2=3.1." JULES RAULIN, Etudes chimiques sur la vegetation. Recherches sur le developpement d'une mucedinee dans un milieu artificiel, p. 192, Paris, 1870. We have seen in the case of yeast that this ratio may be as low as [Proofers note: unreadable symbol]] On the other hand, if we deprive the yeast of air entirely, or cause it to develop in a saccharine medium deprived of free oxygen, it will multiply just as if air were present, although with less activity, and under these circumstances its fermentative character will be most marked; under these circumstances, moreover, we shall find the greatest disproportion, all other conditions being the same, between the weight of yeast formed and the weight of sugar decomposed. Lastly, if free oxygen occurs in varying quantities, the ferment-power of the yeast may pass through all the degrees comprehended between the two extreme limits of which we have just spoken. It seems to us that we could not have a better proof of the direct relation that fermentation bears to life, carried on in the absence of free oxygen, or with a quantity of that gas insufficient for all the acts of nutrition and assimilation. Another equally striking proof of the truth of this theory is the fact previously demonstrated that the ordinary moulds assume the character of a ferment when compelled to live without air, or with quantities of air too scant to permit of their organs having around them as much of that element as is necessary for their life as aerobian plants. Ferments, therefore, only possess in a higher degree a character which belongs to many common moulds, if not to all, and which they share, probably, more or less, with all living cells, namely the power of living either an aerobian or anaerobian life, according to the conditions under which they are placed. It may be readily understood how, in their state of aerobian life, the alcoholic ferments have failed to attract attention. These ferments are only cultivated out of contract with air, at the bottom of liquids which soon become saturated with carbonic acid gas. Air is only present in the earlier developments of their germs, and without attracting the attention of the operator, whilst in their state of anaerobian growth their life and action are of prolonged duration. We must have recourse to special experimental apparatus to enable us to demonstrate the mode of life of alcoholic ferments under the influence of free oxygen; it is their state of existence apart from air, in the depths of liquids, that attracts all our attention. The results of their action are, however, marvellous, if we regard the products resulting from them, in the important industries of which they are the life and soul. In the case of ordinary moulds, the opposite holds good. What we want to use special experimental apparatus for with them, is to enable us to demonstrate the possibility of their continuing to live for a time out of contact with air, and all our attention, in their case, is attracted by the facility with which they develop under the influence of oxygen. Thus the decomposition of saccharine liquids, which is the consequence of the life of fungi without air, is scarcely perceptible, and so is of no practical importance. Their aerial life, on the other hand, in which they respire and accomplish their process of oxidation under the influence of free oxygen is a normal phenomenon, and one of prolonged duration which cannot fail to strike the least thoughtful of observers. We are convinced that a day will come when moulds will be utilised in certain industrial operations, on account of their power in destroying organic matter. The conversion of alcohol into vinegar in the process of acetification and the production of gallic acid by the action of fungi on wet gall nuts, are already connected with this kind of phenomena. [Footnote: We shall show, some day, that the processes of oxidation due to growth of fungi cause, in certain decompositions, liberation of ammonia to a considerable extent, and that by regulating their action we might cause them to extract the nitrogen from a host of organic debris, as also, by checking the production of such organisms, we might considerably increase the proportion of nitrates in the artificial nitrogenous substances. By cultivating the various moulds on the surface of damp bread in a current of air we have obtained an abundance of ammonia, derived from the decomposition of the albuminoids effected by the fungoid life. The decomposition of asparagus and several other animal or vegetable substances has similar results.] On this last subject, the important work of M. Van Tieghem (Annales Scientifiques de l'Ecole Normale, Vol. vi.) may be consulted. The possibility of living without oxygen, in the case of ordinary moulds, is connected with certain morphological modifications which are more marked in proportion as this faculty is itself more developed. These changes in the vegetative forms are scarcely perceptible, in the case of penicillium and mycoderma vini, but they are very evident in the case of aspergillus, consisting of a marked tendency on the part of the submerged mycelial filaments to increase in diameter, and to develop cross partitions at short intervals, so that they sometimes bear a resemblance to chains of conidia. In mucor, again, they are very marked, the inflated filaments which, closely interwoven, present chains of cells, which fall off and bud, gradually producing a mass of cells. If we consider the matter carefully, we shall see that yeast presents the same characteristics. * * * * It is a great presumption in favor of the truth of theoretical ideas when the results of experiments undertaken on the strength of those ideas are confirmed by various facts more recently added to science, and when those ideas force themselves more and more on our minds, in spite of a prima facie improbability. This is exactly the character of those ideas which we have just expounded. We pronounced them in 1861, and not only have they remained unshaken since, but they have served to foreshadow new facts, so that it is much easier to defend them in the present day than it was to do so fifteen years ago. We first called attention to them in various notes, which we read before the Chemical Society of Paris, notably at its meetings of April 12th and June 28th, 1861, and in papers in the Comtes rendus de l'Academie des Sciences. It may be of some interest to quote here, in its entirety, our communication of June 28th, 1861, entitled, "Influences of Oxygen on the Development of Yeast and on Alcoholic Fermentation," which we extract from the Bulletin de la Societe Chimique de Paris:-- "M. Pasteur gives the result of his researches on the fermentation of sugar and the development of yeast-cells, according as that fermentation takes place apart from the influence of free oxygen or in contact with that gas. His experiments, however, have nothing in common with those of Gay- Lussac, which were performed with the juice of grapes crushed under conditions where they would not be affected by air, and then brought into contact with oxygen. "Yeast, when perfectly developed, is able to bud and grow in a saccharine and albuminous liquid, in the complete absence of oxygen or air. In this case but little yeast is formed, and a comparatively large quantity of sugar disappears--sixty or eighty parts for one of yeast formed. Under these conditions fermentation is very sluggish. "If the experiment is made in contact with the air, and with a great surface of liquid, fermentation is rapid. For the same quantity of sugar decomposed much more yeast is formed. The air with which the liquid is in contact is absorbed by the yeast. The yeast develops very actively, but its fermentative character tends to disappear under these conditions; we find, in fact, that for one part of yeast formed, not more than from four to ten parts of sugar are transformed. The fermentative character of this yeast nevertheless, continues, and produces even increased effects, if it is made to act on sugar apart from the influence of free oxygen. "It seems, therefore, natural to admit that when yeast functions as a ferment by living apart from the influence of air, it derives oxygen from the sugar, and that this is the origin of its fermentative character. "M. Pasteur explains the fact of the immense activity at the commencement of fermentations by the influence of the oxygen of the air held in solution in the liquids, at the time when the action commences. The author has found, moreover, that the yeast of beer sown in an albuminous liquid, such as yeast-water, still multiplies, even when there is not a trace of sugar in the liquid, provided always that atmospheric oxygen is present in large quantities. When deprived of air, under these conditions, yeast does not germinate at all. The same experiments may be repeated with albuminous liquid, mixed with a solution of non- fermentable sugar, such as ordinary crystallized milk-sugar. The results are precisely the same. "Yeast formed thus in the absence of sugar does not change its nature; it is still capable of causing sugar to ferment, if brought to bear upon that substance apart from air. It must be remarked, however, that the development of yeast is effected with great difficulty when it has not a fermentable substance for its food. In short, the yeast of beer acts in exactly the same manner as an ordinary plant, and the analogy would be complete if ordinary plants had such an affinity for oxygen as permitted them to breathe by appropriating this element from unstable compounds, in which case, according to M. Pasteur, they would appear as ferments for those substances. "M. Pasteur declares that he hopes to be able to realize this result, that is to say, to discover the conditions under which certain inferior plants may live apart from air in the presence of sugar, causing that substance to ferment as the yeast of beer would do." This summary and the preconceived views that it set forth have lost nothing of their exactness; on the contrary, time has strengthened them. The surmises of the last two paragraphs have received valuable confirmation from recent observations made by Messrs. Lechartier and Bellamy, as well as by ourselves, an account of which we must put before our readers. It is necessary, however, before touching upon this curious feature in connection with fermentations to insist on the accuracy of a passage in the preceding summary; the statement, namely, that yeast could multiply in an albuminous liquid, in which it found a non- fermentable sugar, milk-sugar, for example. The following is an experiment on this point:--On August 15th, 1875, we sowed a trace of yeast in 150 cc. (rather more than 5 fluid ounces) of yeast-- water, containing 2 1/2 per cent, of milk-sugar. The solution was prepared in one of our double-necked flasks, with the necessary precautions to secure the absence of germs, and the yeast sown was itself perfectly pure. Three months afterwards, November 15th, 1875, we examined the liquid for alcohol; it contained only the smallest trace; as for the yeast (which had sensibly developed), collected and dried on a filter paper, it weighed 0.050 gramme (0.76 grain). In this case we have the yeast multiplying without giving rise to the least fermentation, like a fungoid growth, absorbing oxygen, and evolving carbonic acid, and there is no doubt that the cessation of its development in this experiment was due to the progressive deprivation of oxygen that occurred. As soon as the gaseous mixture in the flask consisted entirely of carbonic acid and nitrogen, the vitality of the yeast was dependent on, and in proportion to, the quantity of air which entered the flask in consequence of variations of temperature. The question now arose, was this yeast, which had developed wholly as an ordinary fungus, still capable of manifesting the character of a ferment? To settle this point we had taken the precaution on August 15th, 1875, of preparing another flask, exactly similar to the preceding one in every respect, and which gave results identical with those described. We decanted this November 15th, pouring some wort on the deposit of the plant, which remained in the flask. In less than five hours from the time we placed it in the oven, the plant started fermentation in the wort, as we could see by the bubbles of gas rising to form patches on the surface of the liquid. We may add that yeast in the medium which we have been discussing will not develop at all without air. The importance of these results can escape no one; they prove clearly that the fermentative character is not an invariable phenomenon of yeast-life, they show that yeast is a plant which does not differ from ordinary plants, and which manifests its fermentative power solely in consequence of particular conditions under which it is compelled to live. It may carry on its life as a ferment or not, and after having lived without manifesting the slightest symptom of fermentative character, it is quite ready to manifest that character when brought under suitable conditions. The fermentative property, therefore, is not a power peculiar to cells of a special nature. It is not a permanent character of a particular structure, like, for instance, the property of acidity or alkalinity. It is a peculiarity dependent on external circumstances and on the nutritive conditions of the organism. II. FERMENTATION IN SACCHARINE FRUITS IMMERSED IN CARBONIC ACID GAS The theory which we have, step by step, evolved, on the subject of the cause of the chemical phenomena of fermentation, may claim a character of simplicity and generality that is well worthy of attention. Fermentation is no longer one of those isolated and mysterious phenomena which do not admit of explanation. It is the consequence of a peculiar vital process of nutrition which occurs tinder certain conditions, differing from those which characterize the life of all ordinary beings, animal or vegetable, but by which the latter may be affected, more or less, in a way which brings them, to some extent within the class of ferments, properly so called. We can even conceive that the fermentative character may belong to every organized form, to every animal or vegetable cell, on the sole condition that the chemico-vital acts of assimilation and excretion must be capable of taking place in that cell for a brief period, longer or shorter it may be, without necessity for recourse to supplies of atmospheric oxygen; in other words, the cell must be able to derive its needful heat from the decomposition of some body which yields a surplus of heat in the process. As a consequence of these conclusions it should be an easy matter to show, in the majority of living beings, the manifestation of the phenomena of fermentation; for there are, probably, none in which all chemical action entirely disappears, upon the sudden cessation of life. One day, when we were expressing these views in our laboratory, in the presence of M. Dumas, who seemed inclined to admit their truth, we added: "We should like to make a wager that if we were to plunge a bunch of grapes into carbonic acid gas, there would be immediately produced alcohol and carbonic acid gas, in consequence of a renewed action starting in the interior cells of the grapes, in such a way that these cells would assume the functions of yeast cells. We will make the experiment, and when you come to-morrow--it was our good fortune to have M. Dumas working in our laboratory at that time--we will give you an account of the result." Our predictions were realized. We then endeavoured to find, in the presence of M. Dumas, who assisted us in our endeavour, cells of yeast in the grapes; but it was quite impossible to discover any. [Footnote: To determine the absence of cells of ferment in fruits that have been immersed in carbonic acid gas, we must first of all carefully raise the pellicle of the fruit, taking care that the subjacent parenchyma does not touch the surface of the pellicle, since the organized corpuscles existing on the exterior of the fruit might introduce an error into our miscroscopical observations. Experiments on grapes have given us an explanation of a fact generally known, the cause of which, however, had hitherto escaped our knowledge. We all know that the taste and aroma of the vintage, that is, of the grapes stripped from the bunches and thrown into tubs, where they get soaked in the juice that issues from the wounded specimens, are very different from the taste and aroma of an uninjured bunch. Now grapes that have been immersed in an atmosphere of carbonic acid gas have exactly the flavour and smell of the vintage; the reason is that, in the vintage tub, the grapes are immediately surrounded by an atmosphere of carbonic acid gas, and undergo, in consequence, the fermentation peculiar to grapes that have been plunged into this gas. These facts deserve to be studied from a practical point of view. It would be interesting, for example, to learn what difference there would be in the quality of two wines, the grapes of which, in the once case, had been perfectly crushed, so as to cause as great a separation of the cells of the parenchyma as possible; in the other case, left, for the most part, whole, as in the case in the ordinary vintage. The first wine would be deprived of those fixed and fragrant principles produced by the fermentation of which we have just spoken, when the grapes are immersed in carbonic acid gas, by such a comparison as that which we suggest we should be able to form a priori judgment on the merits of the new system, which had not been carefully studied, although already widely adopted, of milled, cylindrical crushers, for pressing the vintage.] Encouraged by this result, we undertook fresh experiments on grapes, on a melon, on oranges, on plums, and on rhubarb leaves, gathered in the garden of the Ecole Normale, and, in every case, our substance, when immersed in carbonic acid gas, gave rise to the production of alcohol and carbonic acid. We obtained the following surprising results from some prunes de Monsieur:[Footnote: We have sometimes found small quantities of alcohol in fruits and other vegetable organs, surrounded with ordinary air, but always in small proportion, and in a manner which suggested its accidental character. It is east to understand how, in the thickness of certain fruits, certain parts of those fruits might be deprived of air, under which circumstances they would have been acting under conditions similar to those under which fruits act when wholly immersed in the carbonic acid gas. Moreover, it would be useful to determine whether alcohol is not a normal product of vegatation.]--On July 21, 1872, we placed twenty-four of these plums under a glass bell, which we immediately filled with carbonic acid gas. The plums had been gathered on the previous day. By the side of the bell we placed other twenty-four plums, which were left there uncovered. Eight days afterwards, in the course of which time there had been a considerable evolution of carbonic acid from the bell, we withdrew the plums and compared them with those which had been left exposed to the air. The difference was striking, almost incredible. Whilst the plums which had been surrounded with air (the experiments of Berard have long since taught us that, under this latter condition, fruits absorb oxygen from the air and emit carbonic acid gas in almost equal volume) had become very soft and watery and sweet, the plums taken from under the jar had remained very firm and hard, the flesh was by no means watery, but they had lost much sugar. Lastly, when submitted to distillation, after crushing, they yielded 6.5 grammes (99.7 grains) of alcohol, more than 1 per cent, of the total weight of the plums. What better proof than these facts could we have of the existence of a considerable chemical action in the interior of fruit, an action which derives the heat necessary for its manifestation from the decomposition of the sugar present in the cells? Moreover, and this circumstance is especially worthy of our attention, in all these experiments we found that there was a liberation of heat, of which the fruits and other organs were the seat, as soon as they were plunged in the carbonic acid gas. This heat is so considerable that it may at times be detected by the hand, if the two sides of the bell, one of which is in contact with the objects, are touched alternately. It also makes itself evident in the formation of little drops on those parts of the bell which are less directly exposed to the influence of the heat resulting from the decomposition of the sugar of the cells. [Footnote: In these studies of plants living immersed in carbonic acid gas, we have come across a fact which corroborated those which we have already given in reference to the facility with which lactic and viscous ferments, and generally speaking, those which we have termed the disease ferments or beer, develop when deprived of air, and which shows, consequently, how very marked their aerobian character is. If we immerse beet-roots or turnips in carbonic acid gas, we produce well-defined fermentations in those roots. Their whole surface readily permits the escape of the highly acid liquids, and they become filled with lactic, viscous, and other ferments, This shows us the great danger which may result from the use of pits, in which the beet-roots are preserved, when the air is not renewed, and that the original oxygen is expelled by the vital processes of fungi or other deoxidizing chemical actions. We nave directed the attention of the manufacturers of beet-root sugar to this point.] In short, fermentation is a very general phenomenon. It is life without air, or life without free oxygen, or, more generally still, it is the result of a chemical process accomplished on a fermentable substance capable of producing heat by its decomposition, in which process the entire heat used up is derived from a part of the heat that the decomposition of the fermentable substance sets free. The class of fermentations properly so called, is, however, restricted by the small number of substances capable of decomposing with the production of heat, and at the same time of serving for the nourishment of lower forms of life, when deprived of the presence and action of air. This, again, is a consequence of our theory, which is well worthy of notice, The facts that we have just mentioned in reference to the formation of alcohol and carbonic acid in the substance of ripe fruits, under special conditions, and apart from the action of ferment, are already known to science. They were discovered in 1869 by M. Lechartier, formerly a pupil in the Ecole Normale Superieure, and his coadjutor, M. Bellamy. [Footnote: Lechartier and Bellamy, Comptes rendus de l'Academie des Sciences, vol. lxix., pp., 366 and 466, 1869.] In 1821, in a very remarkable work, especially when we consider the period when it appeared, Berard demonstrated several important propositions in connection with the maturation of fruits: I. All fruits, even those that are still green, and likewise even those that are exposed to the sun, absorb oxygen and set free an almost equal volume of carbonic acid gas. This is a condition of their proper ripening. II. Ripe fruits placed in a limited atmosphere, after having absorbed all the oxygen and set free an almost equal volume of carbonic acid, continue to emit that gas in notable quantity, even when no bruise is to be seen--"as though by a kind of fermentation," as Berard actually observes--and lose their saccharine particles, a circumstance which causes the fruits to appear more acid, although the actual weight of their acid may undergo no augmentation whatever. In this beautiful work, and in all subsequent ones of which the ripening of fruits has been the subject, two facts of great theoretical value have escaped the notice of the authors; these are the two facts which Messrs. Lechartier and Bellamy pointed out for the first time, namely, the production of alcohol and the absence of cells of ferments. It is worthy of remark that these two facts, as we have shown above, were actually fore-shadowed in the theory of fermentation that we advocated as far back as 1861, and we are happy to add that Messrs. Lechartier and Bellamy, who at first had prudently drawn no theoretical conclusions from their work, now entirely agree with the theory we have advanced. [Footnote: Those gentlemen express themselves thus: "In a note presented to the Academy in November, 1872, we published certain experiments which showed that carbonic acid and alcohol may be produced in fruits kept in a closed vessel, out of contact with atmospheric oxygen, without our being able to discover alcoholic ferment in the interior of those fruits. "M. Pasteur, as a logical deduction from the principle which he has established in connection with the theory of fermentation, considers that THE FORMATION OF ALCOHOL MAY BE ATTRIBUTED TO THE FACT THAT THE PHYSICAL AND CHEMICAL PRECESSES OF LIFE IN THE CELLS OF FRUIT CONTINUE UNDER NEW CONDITIONS, IN A MANNER SIMILAR TO THOSE OF THE CELLS OF FERMENT. Experiments, continued during 1872, 1873, and 1874, on different fruits have furnished results all of which seem to us to harmonize with this proposition, and to establish it on a firm basis of proof."--Comptes rendus, t. lxxix., p. 949, 1874.] Their mode of reasoning is very different from that of the savants with whom we discussed the subject before the Academy, on the occasion when the communication which we addressed to the Academy in October, 1872, attracted attention once more to the remarkable observations of Messrs. Lechartier and Bellamy. [Footnote: PASTEUR, Faites nouveaux pour servir a la connaissance de la theorie des fermentations proprement dites. (Comptes rendus de l'Academie des Sciences, t. lxxv., p. 784.) See in the same volume the discussion that followed; also, PASTEUR, Note sur la production de l'alcool par les fruits, same volume, p. 1054, in which we recount the observations anterior to our own, made by Messrs. Lechartier and Bellamy in 1869.] M. Fremy, in particular, was desirous of finding in these observations a confirmation of his views on the subject of hemi- organism, and a condemnation of ours, notwithstanding the fact that the preceding explanations, and, more particularly our Note of 1861, quoted word for word in the preceding section, furnish the most conclusive evidence in favor of those ideas which we advocate. Indeed, as far back as 1861 we pointed out very clearly that if we could find plants able to live when deprived of air, in the presence of sugar, they would bring about a fermentation of that substance, in the same manner that yeast does. Such is the case with the fungi already studied; such, too, is the case with the fruits employed in the experiments of Messrs. Lechartier and Bellamy, and in our own experiments, the results of which not only confirm those obtained by these gentlemen, but even extend them, in so far as we have shown that fruits, when surrounded with carbonic acid gas immediately produce alcohol. When surrounded with air, they live in their aerobian state and we have no fermentation; immersed immediately afterwards in carbonic acid gas, they now assume their anaerobian state, and at once begin to act upon the sugar in the manner of ferments, and emit heat. As for seeing in these facts anything like a confirmation of the theory of hemi-organism, imagined by M. Fremy, the idea of such a thing is absurd. The following, for instance, is the theory of the fermentation of the vintage, according to M. Fremy. [Footnote: Comptes rendus, meeting of January 15th, 1872.] "To speak here of alcoholic fermentation alone," our author says, "I hold that in the production of wine it is the juice of the fruit itself that, in contact with air, produces grains of ferment, by the transformation of the albuminous matter; Pasteur, on the other hand, maintains that the fermentation is produced by germs existing outside of the grapes." [Footnote: As a matter of fact, M. Fremy applies his theory of hemi-organism, not only to the alcoholic fermentation of grape juice, but to all other fermentations. The following passage occurs in one of his notes (Comptes rendus de l'Academie, t. lxxv., p. 979, October 28th, 1872): "Experiments on Germinated Barley.--The object of these was to show that when barley, left to itself in sweetened water, produces in succession alcoholic, lactic, butyric, and acetic fermentations, these modifications are brought about by ferments which are produced inside the grains themselves, and not by atmospheric germs. More than forty different experiments were devoted to this part of my work." Need we add that this assertion is based on no substantial foundation? The cells belonging to the grains of barley, or their albuminous contents, never do produce cells of alcoholic ferment, or of lactic ferment, or butyric vibrios. Whenever those ferments appear, they may be traced to germs of those organisms, diffused throughout the interior of the grains, or adhering to the exterior surface, or existing in the water employed, or on the side of the vessels used. There are many ways of demonstrating this, of which the following is one: Since the results of our experiments have shown that sweetened water, phosphates, and chalk very readily give rise to lactic and butyric fermentations, what reason is there for supposing that if we substitute grains of barley for chalk, the lactic and butyric ferments will spring from those grains, in consequence of a transformation of their cells and albuminous substances? Surely there is no ground for maintaining that they are produced by hemi-organism, since a medium composed of sugar, or chalk, or phosphates of ammonia, potash, or magnesia contains no albuminous substances. This is an indirect but irresistible argument against the hemi-organism theory.] Now what bearing on this purely imaginary theory can the fact have, that a whole fruit, immersed in carbonic acid gas, immediately produces alcohol and carbonic acid? In the preceding passage which we have borrowed from M. Fremy, an indispensable condition of the transformation of the albuminous matter is the contact with air and the crushing of the grapes. Here, however, we are dealing with UNINJURED FRUITS IN CONTACT WITH CARBONIC ACID GAS. Our theory, on the other hand, which, we may repeat, we have advocated since 1861, maintains that all cells become fermentative when their vital action is protracted in the absence of air, which are precisely the conditions that hold in the experiments on fruits immersed in carbonic acid gas. The vital energy is not immediately suspended in their cells, and the latter are deprived of air. Consequently, fermentation must result. Moreover, we may add, if we destroy the fruit, or crush it before immersing it in the gas, it no longer produces alcohol or fermentation of any kind, a circumstance that may be attributed to the fact of the destruction of vital action in the crushed fruit. On the other hand, in what way ought this crushing to affect the hypothesis of hemi-organism? The crushed fruit ought to act quite as well, or even better than that which is uncrushed. In short, nothing can be more directly opposed to the theory of the mode of manifestation of that hidden force to which the name of hemi-organism has been given, than the discovery of the production of these phenomena of fermentation in fruits surrounded with carbonic acid gas; whilst the theory, which sees in fermentation a consequence of vital energy in absence of air, finds in these facts the strictest confirmation of an express prediction, which from the first formed an integral part of its statement. We should not be justified in devoting further time to opinions which are not supported by any serious experiment. Abroad, as well as in France, the theory of the transformation of albuminous substances into organized ferments had been advocated long before it had been taken up by M. Fremy. It no longer commands the slightest credit, nor do any observers of note any longer give it the least attention; it might even be said that it has become a subject of ridicule. An attempt has also been made to prove that we have contradicted ourselves, inasmuch as in 1860 we published our opinion that alcoholic fermentation can never occur without a simultaneous occurrence of organization, development, and multiplication of globules; or continued life, carried on from globules already formed. [Footnote: PASTEUR, Memoire sur la fermentation alcoolique, 1860: Annales de Chimie et de Physique. The word globules is here used for cells. In our researches we have always endeavoured to prevent any confusion of ideas. We stated at the beginning of our Memoir of 1860 that: "We apply the term alcoholic to that fermentation which sugar undergoes under the influence of the ferment known as BEER YEAST." This is, the fermentation which produces wine and all alcoholic beverages. This, too, is regarded as the type for a host of similar phenomena designated, by general usage, under the generic name of fermentation, and qualified by the name of one of the essential products of the special phenomenon under observation. Bearing in mind this fact in reference to the nomenclature that we have adopted it will be seen that the expression ALCOHOLIC FERMENTATION cannot be applied to every phenomenon of fermentation in which alcohol is produced, inasmuch as there may be a number of phenomena having this character in common. If we had not at starting defined that particular one amongst the number of very distinct phenomena, which, to the exclusion of the others, should bear the name of alcoholic fermentation, we should inevitably have given rise to a confusion of language that would soon pass from words to ideas, and tend to introduce unnecessary complexity into researches which are already, in themselves, sufficiently complex to necessitate the adoption of scrupulous care to prevent their becoming still more involved. It seems to us that any further doubt as to the meaning of the words ALCOHOLIC FERMENTATION, and the sense in which they are employed, is impossible, inasmuch as Lavoisier, Gay-Lussac, and Thenard have applied this term to the fermentation of sugar by means of beer yeast. It would be both dangerous and unprofitable to discard the example set by these illustrious masters, to whom we are indebted for our earliest knowledge of this subject.] Nothing, however, can be truer than that opinion, and at the present moment, after fifteen years of study devoted to the subject since the publication to which we have referred, we need no longer say, "we think," but instead, "we affirm," that it is correct. It is, as a matter of fact, to alcoholic fermentation, properly so called, that the charge to which we have referred relates--to that fermentation which yields, besides alcohol, carbonic acid, succinic acid, glycerine, volatile acids, and other products. This fermentation undoubtedly requires the presence of yeast--cells under the conditions that we have named. Those who have contradicted us have fallen into the error of supposing that the fermentation of fruits is an ordinary alcoholic fermentation, identical with that produced by beer yeast, and that, consequently, the cells of that yeast must, according to own theory, be always present. There is not the least authority for such a supposition. When we come to exact quantitative estimations--and these are to be found in the figures supplied by Messrs. Lechartier and Bellamy--it will be seen that the proportions of alcohol and carbonic acid gas produced in the fermentation of fruits differ widely from those that we find in alcoholic fermentations properly so called, as must necessarily be the case since in the former the fermentaction is effected by the cells of a fruit, but in the latter by cells of ordinary alcoholic ferment. Indeed we have a strong conviction that each fruit would be found to give rise to special action, the chemical equation of which would be different from that in the case of other fruits. As for the circumstance that the cells of these fruits cause fermentation without multiplying, this comes under the kind of activity which we have already distinguished by the expression CONTINUOUS LIFE IN CELLS ALREADY FORMED. We will conclude this section with a few remarks on the subject of equations of fermentations, which have been suggested to us principally in attempts to explain the results derived from the fermentation of fruits immersed in carbonic acid gas. Originally, when fermentations were put amongst the class of decompositions by contact-action, it seemed probable, and, in fact, was believed, that every fermentation has its own well- defined equation which never varied. In the present day, on the contrary, it must be borne in mind that the equation of a fermentation varies essentially with the conditions under which that fermentation is accomplished, and that a statement of this equation is a problem no less complicated than that in the case of the nutrition of a living being. To every fermentation may be assigned an equation in a general sort of way, an equation, however, which, in numerous points of detail, is liable to the thousand variations connected with the phenomena of life. Moreover, there will be as many distinct fermentations brought about by one ferment as there are fermentable substances capable of supplying the carbon element of the food of that same ferment, in the same way that the equation of the nutrition of an animal will vary with the nature of the food which it consumes. As regards fermentation producing alcohol, which may be effected by several different ferments, there will be as in the case of a given sugar, as many general equations as there are ferments, whether they be ferment-cells properly so called, or cells of the organs of living beings functioning as ferments. In the same way the equation of nutrition varies in the case of different animals nourished on the same food. And it is from the same reason that ordinary wort produces such a variety of beers when treated with the numerous alcoholic ferments which we have described. These remarks are applicable to all ferments alike; for instance, butyric ferment is capable of producing a host of distinct fermentations, in consequence of its ability to derive the carbonaceous part of its food from very different substances, from sugar, or lactic acid, or glycerine, or mannite, and many others. When we say that every fermentation has its own peculiar ferment, it must be understood that we are speaking of the fermentation considered as a whole, including all the accessory products. We do not mean to imply that the ferment in question is not capable of acting on some other fermentable substance and giving rise to fermentation of a very different kind. Moreover, it is quite erroneous to suppose that the presence of a single one of the products of a fermentation implies the co-existence of a particular ferment. If, for example, we find alcohol among the products of a fermentation, or even alcohol and carbonic acid gas together, this does not prove that the ferment must be an alcoholic ferment, belonging to alcoholic fermentations, in the strict sense of the term. Nor, again, does the mere presence of lactic acid necessarily imply the presence of lactic ferment. As a matter of fact, different fermentations may give rise to one or even several identical products. We could not say with certainty, from a purely chemical point of view, that we were dealing, for example, with an alcoholic fermentation properly so called, and that the yeast of beer must be present in it, if we had not first determined the presence of all the numerous products of that particular fermentation under conditions similar to those under which the fermentation in question had occurred. In works on fermentation the reader will often find those confusions against which we are now attempting to guard him. It is precisely in consequence of not having had their attention drawn to such observations that some have imagined that the fermentation in fruits immersed in carbonic acid gas is in contradiction to the assertion which we originally made in our Memoir on alcoholic fermentation published in 1860, the exact words of which we may here repeat:--"The chemical phenomena of fermentation are related essentially to a vital activity, beginning and ending with the latter; we believe that alcoholic fermentation never occurs"--we were discussing the question of ordinary alcoholic fermentation produced by the yeast of beer--"without the simultaneous occurrence of organization, development, and multiplication of globules, or continued life, carried on by means of the globules already formed. The general results of the present Memoir seem to us to be it direct opposition to the opinions of MM. Liebig and Berzelius." These conclusions, we repeat, are as true now as they ever were, and are as applicable to the fermentation of fruits, of which nothing was known in 1860, as they are to the fermentation produced by the means of yeast. Only, in the case of fruits, it is the cells of the parenchyma that function as ferment, by a continuation of their activity in carbonic acid gas whilst in the other case the ferment consists of cells of yeast. There should be nothing very surprising in the fact that fermentation can originate in fruits and form alcohol without the presence of yeast, if the fermentation of fruits were not confounded completely with alcoholic fermentation yielding the same products and in the same proportions. It is through the misuse of words that the fermentation of fruits has been termed alcoholic, in a way which has misled many persons. [Footnote: See, for example, the communications of MM. Colin and Poggiale, and the discussion on them. In the Bulletin de l'Academie de Medecine, March 2d, 9th, and 30th, and February 16th and 23rd, 1875.] In this fermentation, neither alcohol nor carbonic acid gas exists in those proportions in which they are found in fermentation produced by yeast; and, although we may determine in it the presence of succinic acid, glycerine, and a small quantity of volatile acids [Footnote: We have elsewhere determined the formation of minute quantities of volatile acids in alcoholic fermentation. M. Bechamp, who studied these, recognized several belonging to the series of fatty acids, acetic acid, butyric acid &c. "The presence of succinic acid is not accidental, but constant; if we put aside volatile acids that form in quantities which we may call infinitely small, we may say that succinic acid is the only normal acid of alcoholic fermentation."--PASTEUR, Comptes rendus de l' Academie, t. xlvii., P. 224, 1858] the relative proportions of these substances will be different from what they are in the case of alcoholic fermentation. III. REPLY TO CERTAIN CRITICAL OBSERVATIONS OF THE GERMAN NATURALISTS, OSCAR BREFELD AND MORITZ TRAUBE. The essential point of the theory of fermentation which we have been concerned in proving in the preceding paragraphs may be briefly put in the statement that ferments properly so called constitute a class of beings possessing the faculty of living out of contact with free oxygen; or, more concisely still, we may say that fermentation is a result of life without air. If our affirmation were inexact, if ferment cells did require for their growth or for their increase in number or weight, as all other vegetable cells do, the presence of oxygen, whether gaseous or held in solution in liquids, this new theory would lose all value, its very raison d'etre would be gone, at least as far as the most important part of fermentations is concerned. This is precisely what M. Oscar Brefeld has endeavoured to prove in a Memoir read to the Physico-Medical Society of Wurzburg on July 26th, 1873, in which, although we have ample evidence of the great experimental skill of its author, he has nevertheless, in our opinion, arrived at conclusions entirely opposed to fact. "From the experiments which I have just described," he says, "it follows, in the most indisputable manner, that A FERMENT CANNOT INCREASE WITHOUT FREE OXYGEN. Pasteur's supposition that a ferment, unlike all other living organisms, can live and increase at the expense of oxygen held in combination, is, consequently, altogether wanting in any solid basis of experimental proof. Moreover, since, according to the theory of Pasteur, it is precisely this faculty of living and increasing at the expense of the oxygen held in combination that constitutes the phenomenon of fermentation, it follows that the whole theory, commanding though it does such general assent, is shown to be untenable; it is simply inaccurate." The experiments to which Dr. Brefeld alludes, consisted in keeping under continued study with the microscope, in a room specially prepared for the purpose, one or more cells of ferment in wort in an atmosphere of carbonic acid gas free from the least traces of free oxygen. We have, however, recognized the fact that the increase of a ferment out of contact with air is only possible in the case of a very young specimen; but our author employed brewer's yeast taken after fermentation, and to this fact we may attribute the non-success of his growths. Dr. Brefeld, without knowing it, operated on yeast in one of the states in which it requires gaseous oxygen to enable it to germinate again. A perusal of what we have previously written on the subject of the revival of yeast according to its age will show how widely the time required for such revival may vary in different cases. What may be perfectly true of the state of a yeast to-day may not be so to-morrow, since yeast is continually undergoing modifications. We have already shown the energy and activity with which a ferment can vegetate in the presence of free oxygen, and we have pointed out the great extent to which a very small quantity; of oxygen held in solution in fermenting liquids can operate at the beginning of fermentation. It is this oxygen that produces revival in the cells of the ferment and enables them to resume the faculty of germinating and continuing their life, and of multiplying when deprived of air. In our opinion, a simple reflection should have guarded Dr. Brefeld against the interpretation which he has attached to his observations. If a cell of ferment cannot bud or increase without absorbing oxygen, either free or held in solution in the liquid, the ratio between the weight of the ferment formed during fermentation and that of oxygen used up must be constant. We had, however, clearly established, as far back as 1861, the fact that this ratio is extremely variable, a fact, moreover, which is placed beyond doubt by the experiments described in the preceding section. Though but small quantities of oxygen are absorbed, a considerable weight of ferment may be generated; whilst if the ferment has abundance of oxygen at its disposal, it will absorb much, and the weight of yeast formed will be still greater. The ratio between the weight of ferment formed and that of sugar decomposed may pass through all stages within certain very wide limits, the variations depending on the greater or less absorption of free oxygen. And in this fact, we believe, lies one of the most essential supports of the theory which we advocate. In denouncing the impossibility, as he considered it, of a ferment living without air or oxygen, and so acting in defiance of that law which governs all living beings, animal or vegetable, Dr. Brefeld ought also to have borne in mind the fact which we have pointed out, that alcoholic yeast is not the only organized ferment which lives in an anaerobian state. It is really a small matter that one more ferment should be placed in a list of exceptions to the generality of living beings, for whom there is a rigid law in their vital economy which requires for continued life a continuous respiration, a continuous supply of free oxygen. Why, for instance, has Dr. Brefeld omitted the facts bearing on the life of the vibrios of butyric fermentation? Doubtless he thought we were equally mistaken in these: a few actual experiments would have put him right. These remarks on the criticisms of Dr. Brefeld are also applicable to certain observations of M. Moritz Traube's, although, as regards the principal object of Dr. Brefeld's attack, we are indebted to M. Traube for our defence. This gentleman maintained the exactness of our results before the Chemical Society of Berlin, proving by fresh experiments that yeast is able to live and multiply without the intervention of oxygen. "My researches," he said, "confirm in an indisputable manner M. Pasteur's assertion that the multiplication of yeast can take place in media which contain no trace of free oxygen. ... M. Brefeld's assertion to the contrary is erroneous." But immediately afterwards M. Traube adds: "Have we here a confirmation of Pasteur's theory? By no means. The results of my experiments demonstrate on the contrary that this theory has no true foundation." What were these results? Whilst proving that yeast could live without air, M. Traube, as we ourselves did, found that it had great difficulty in living under these conditions; indeed he never succeeded in obtaining more than the first stages of true fermentation. This was doubtless for the two following reasons: first, in consequence of the accidental production of secondary and diseased fermentations which frequently prevent the propagation of alcoholic ferment; and, secondly, in consequence of the original exhausted condition of the yeast employed. As long ago as 1861, we pointed out the slowness and difficulty of the vital action of yeast when deprived of air; and a little way back, in the preceding section, we have called attention to certain fermentations that cannot be completed under such conditions without going into the causes of these peculiarities. M. Traube expresses himself thus: "Pasteur's conclusion, that yeast in the absence of air is able to derive the oxygen necessary for its development from sugar, is erroneous; its increase is arrested even when the greater part of the sugar still remains undecomposed. IT IS IN A MIXTURE OF ALBUMINOUS SUBSTANCES THAT YEAST, WHEN DEPRIVED OF AIR, FINDS THE MATERIALS FOR ITS DEVELOPMENT." This last assertion of M. Traube's is entirely disproved by those fermentation experiments in which, after suppressing the presence of albuminous substances, the action, nevertheless, went on in a purely inorganic medium, out of contact with air, a fact, of which we shall give irrefutable proofs. [Footnote: Traube's conceptions are governed by a theory of fermentation entirely his own, a hypothetical one, as he admits, of which the following is a brief summary: "We have no reason to doubt," Traube says, "that the protoplasm of vegetable cells is itself, or contains within it, a chemical ferment which causes the alcoholic fermentation of sugar; its efficacy seems closely connected with the presence of the cell, inasmuch as, up to the present time, we have discovered no means of isolating it from the cells with success. In the presence of air this ferment oxidizes sugar by bringing oxygen to bear upon it; in the absence of air it decomposes the sugar by taking away oxygen from one group of atoms of the molecule of sugar and bringing it to act upon other atoms; on the one hand yielding a product of alcohol by reduction, on the other hand a product of carbonic acid gas by oxidation." Traube supposes that this chemical ferment exists in yeast and in all sweet fruits, but only when the cells are intact, for he has proved for himself that thoroughly crushed fruits give rise to no fermentation whatever in carbonic acid gas. In this respect this imaginary chemical ferment would differ entirely from those which we call SOLUBLE FERMENTS, since diastase, emulsine, &c., may be easily isolated. For a full account of the views of Brefeld and Traube, and the discussion which they carried on on the subject of the results of our experiments, our readers may consult the Journal of the Chemical Society of Berlin, vii., p. 872. The numbers for September and December, 1874, in the same volume, contain the replies of the two authors.] IV. FERMENTATION OF DEXTRO-TARTRATE OF LIME. [Footnote: See PASTEUR, Comptes rendus de l'Academie des Sciences, t. lvi., p. 416.] Tartrate of lime, in spite of its insolubility in waters is capable of complete fermentation in a mineral medium. If we put some pure tartrate of lime, in the form of a granulated, crystalline powder, into pure water, together with some sulphate of ammonia and phosphates of potassium and magnesium, in very small proportions, a spontaneous fermentation will take place in the deposit in the course of a few days, although no germs of ferment have been added. A living, organized ferment, of the vibrionic type, filiform, with tortuous motions, and often of immense length, forms spontaneously by the development of some germs derived in some way from the inevitable particles of dust floating in the air or resting on the surface of the vessels or material which we employ. The germs of the vibrios concerned in putrefaction are diffused around us on every side, and, in all probability, it is one or more of these germs that develop in the medium in question. In this way they effect the decomposition of the tartrate, from which they must necessarily obtain the carbon of their food without which they cannot exist, while the nitrogen is furnished by the ammonia of the ammoniacal salt, the mineral principles by the phosphate of potassium and magnesium, and the sulphur by the sulphate of ammonia. How strange to see organization, life, and motion originating under such conditions! Stranger still to think that this organization, life, and motion are effected without the participation of free oxygen. Once the germ gets a primary impulse on its living career by access of oxygen, it goes on reproducing indefinitely, absolutely without atmospheric air. Here then we have a fact which it is important to establish beyond the possibility of doubt, that we may prove that yeast is not the only organized ferment able to live and multiply when out of the influence of free oxygen. Into a flask, like that represented in FIG. 9, of 2.5 litres (about four pints) in capacity, we put: Pure, crystallized, neutral tartrate of lime. .. 100 grammes Phosphate of ammonia. ... . ... . .. ... . ... 1 grammes Phosphate of magnesium. ... . ... . ... . ... .. 1 grammes Phosphate of potassium. ... . ... . ... . .. 0.5 grammes Sulphate of ammonia. ... . ... . ... . ... .. 0.5 grammes (1 gramme = 15.43 grains) To this we added pure distilled water, so as entirely to fill the flask. In order to expel all the air dissolved in the water and adhering to the solid substances, we first placed our flask in a bath of chloride of calcium in a large cylindrical white iron pot set over a flame. The exit tube of the flask was plunged in a test tube of Bohemian glass three-quarters full of distilled water, and also heated by a flame. We boiled the liquids in the flask and test-tube for a sufficient time to expel all the air contained in them. We then withdrew the heat from under the test- tube, and immediately afterwards covered the water which it contained with a layer of oil and then permitted the whole apparatus to cool down. [Illustration with caption: Fig. 9] Next day we applied a finger to the open extremity of the exit- tube, which we then plunged in a vessel of mercury. In this particular experiment which we are describing, we permitted the flask to remain in this state for a fort-night. It might have remained there for a century without ever manifesting the least sign of fermentation, the fermentation of the tartrate being a consequence of life, and life after boiling no longer existed in the flask. When it was evident that the contents of the flask were perfectly inert, we impregnated them rapidly, as follows: all the liquid contained in the exit-tube was removed by means of a fine caoutchouc tube, and replaced by about 1 c. (about 17 minims) of liquid and deposit from another flask, similar to the one we have just described, but which had been fermenting spontaneously for twelve days; we lost no time in refilling completely the exit tube with water which had been first boiled and then cooled down in carbonic acid gas. This operation lasted only a few minutes. The exit-tube was again plunged under mercury. Subsequently the tube was not moved from under the mercury, and as it formed part of the flask, and there was neither cork nor india-rubber, any introduction of air was consequently impossible. The small quantity of air introduced during the impregnation was insignificant and it might even be shown that it injured rather than assisted the growth of the organisms, inasmuch as these consisted of adult individuals which had lived without air and might be liable to be damaged or even destroyed by it. Be this as it may, in a subsequent experiment we shall find the possibility removed of any aeration taking place in this way, however infinitesimal, so that no doubts may linger on this subject. The following days the organisms multiplied, the deposit of tartrate gradually disappeared, and a sensible ferment action was manifest on the surface, and throughout the bulk of the liquid. The deposit seemed lifted up in places, and was covered with a layer of dark-grey colour, puffed up, and having an organic and gelatinous appearance. For several days, in spite of this action in the deposit, we detected no disengagement of gas, except when the flask was slightly shaken, in which case rather large bubbles adhering to the deposit rose, carrying with them some solid particles, which quickly fell back again, whilst the bubbles diminished in size as they rose, from being partially taken into solution, in consequence of the liquid not being saturated. The smallest bubbles had even time to dissolve completely before they could reach the surface of the liquid. In course of time the liquid was saturated, and the tartrate was gradually displaced by mammillated crusts, or clear, transparent crystals of carbonate of lime at the bottom and on the sides of the vessel. The impregnation took place on February 10th, and on March 15th the liquid was nearly saturated. The bubbles then began to lodge in the bent part of the exit-tube, at the top of the flask. A glass measuring-tube containing mercury was now placed with its open end over the point of the exit-tube under the mercury in the trough, so that no bubble might escape. A steady evolution of gas went on from the 17th to the 18th, 17.4 cc. (1.06 cubic inches) having been collected. This was proved to be nearly absolutely pure carbonic acid, as indeed might have been suspected from the fact that the evolution did not begin before a distinct saturation of the liquid was observed. [Footnote: Carbonic add being considerably more soluble than other gases possible under the circumstances.--ED.] The liquid, which was turbid on the day after its impregnation, had, in spite of the liberation of gas, again become so transparent that we could read our handwriting through the body of the flask. Notwithstanding this, there was still a very active operation going on in the deposit, but it was confined to that spot. Indeed, the swarming vibrios were bound to remain there, the tartrate of lime being still more insoluble in water saturated with carbonate of lime than it is in pure water. A supply of carbonaceous food, at all events, was absolutely wanting in the bulk of the liquid. Every day we continued to collect and analyze the total amount of gas disengaged. To the very last it was composed of pure carbonic acid gas. Only during the first few days did the absorption by the concentrated potash leave a very minute residue. By April 26th all liberation of gas had ceased, the last bubbles having risen in the course of April 23rd. The flask had been all the time in the oven, at a temperature between 25 degrees C. and 28 degrees C. (77 degrees F. and 83 degrees F.). The total volume of gas collected was 2.135 litres (130.2 cubic inches). To obtain the whole volume of gas formed we had to add to this what was held in the liquid in the state of acid carbonate of lime. To determine this we poured a portion of the liquid from the flask into another flask of similar shape, but smaller, up to the gaugemark on the neck. [Footnote: We had to avoid filling the small flask completely, for fear of causing some of the liquid to pass on to the surface of the mercury in the measuring tube. The liquid condensed by boiling forms pure water, the solvent affinity of which for carbonic acid, at the temperature we employ, is well known. This smaller flask had been previously filled with carbonic acid. The carbonic acid of the fermented liquid was then expelled by means of heat, and collected over mercury. In this way we found a volume of 8.322 litres (508 cubic inches) of gas in solution, which, added to the 2.135 litres, gave a total of 10.457 litres (638.2 cubic inches) at 20 degrees and 760 mm., which, calculated to 0 degrees, C. and 760 mm. atmospheric pressure (32 degrees F. and 30 inches) gave a weight of 19.700 grammes (302.2 grains) of carbonic acid. Exactly half of the lime in the tartrate employed got used up in the soluble salts formed during fermentation; the other half was partly precipitated in the form of carbonate of lime, partly dissolved in the liquid by the carbonic acid. The soluble salts seemed to us to be a mixture or combination of 1 equivalent of metacetate of lime, with 2 equivalents of the acetate, for every 10 equivalents of carbonic acid produced, the whole corresponding to the fermentation of 3 equivalents of neutral tartrate of lime. [Footnote: The following is a curious consequence of these numbers and of the nature of the products of this fermentation. The carbonic acid liberated being quite pure, especially when the liquid has been boiled to expel all air from the flask, and capable of perfect solution, it follows that the volume of liquid being sufficient and the weight of tartrate suitably chosen--we may set aside tartrate of lime in an insoluble, crystalline powder, alone with phosphates at the bottom of a closed vessel full of water, and find soon afterwards in their place carbonate of lime, and in the liquid soluble salts of lime, with a mass of organic matter at the bottom, without any liberation of gas or appearance of fermentation ever taking place, except as far as the vital action and transformation in the tartrate are concerned. It is easy to calculate that a vessel or flask of five litres (rather more than a gallon) would be large enough for the accomplishment of this remarkable and singularly quiet transformation, in the case of 50 grammes (767 grains) of tartrate of lime.]. This point, however, is worthy of being studied with greater care: the present statement of the nature of the products formed is given with all reserve. For our point, indeed, the matter is of little importance, since the equation of the fermentation does not concern us. After the completion of fermentation there was not a trace of tartrate of lime remaining at the bottom of the vessel: it had disappeared gradually as it got broken up into the different products of fermentation, and its place was taken by some crystallized carbonate of lime--the excess, namely, which had been unable to dissolve by the action of the carbonic acid. Associated, moreover, with this carbonate of lime there was a quantity of some kind of animal matter, which, under the microscope, appeared to be composed of masses of granules mixed with very fine filaments of varying lengths, studded with minute dots, and presenting all the characteristics of a nitrogenous organic substance. [Footnote: We treated the whole deposit with dilute hydrochloric acid, which dissolved the carbonate of lime and the insoluble phosphates of calcium and magnesium; afterwards filtering the liquid through a weighed filter paper. Dried at 100 degrees C. (212 degrees F.), the weight of the organic matter thus obtained was 0.54 gramme (8.3 grains), which was rather more than 1/200 of the weight of fermentable matter.] That this was really the ferment is evident enough from all that we have already said. To convince ourselves more thoroughly of the fact, and at the same time to enable us to observe the mode of activity of the organism, we instituted the following supplementary observation. Side by side with the experiment just described, we conducted a similar one, which we intermitted after the fermentation was somewhat advanced, and about half of the tartrate dissolved. Breaking off with a file the exit-tube at the point where the neck began to narrow off, we took some of the deposit from the bottom by means of a long straight piece of tubing, in order to bring it under microscopical examination. We found it to consist of a host of long filaments of extreme tenuity, their diameter being about 1/1000th of a millimetre (0.000039 in.); their length varied, in some cases being as much as 1/20th of a millimetre (0.0019 in.). A crowd of these long vibrios were to be seen creeping slowly along, with a sinuous movement, showing three, four, or even five flexures. The filaments that were at rest had the same aspect as these last, with the exception that they appeared punctuate, as though composed of a series of granules arranged in irregular order. No doubt these were vibrios in which vital action had ceased, exhausted specimens which we may compare with the old granular ferment of beer, whilst those in motion may be compared with young and vigorous yeast. The absence of movement in the former seems to prove that this view is correct. Both kinds showed a tendency to form clusters, the compactness of which impeded the movements of those which were in motion. Moreover, it was noticeable that the masses of these latter rested on tartrate not yet dissolved, whilst the granular clusters of the others rested directly on the glass, at the bottom of the flask, as if, having decomposed the tartrate, the only carbonaceous food at their disposal, they had then died on the spot where we captured them, from inability to escape, precisely in consequence of that state of entanglement which they combined to form, during the period of their active development. Besides these we observed vibrios of the same diameter, but of much smaller length, whirling round with great rapidity, and darting backwards and forwards; these were probably identical with the longer ones, and possessed greater freedom of movement, no doubt in consequence of their shortness. Not one of these vibrios could be found throughout the mass of the liquid. [Illustration with caption: Figure 10.] We may remark that as there was a somewhat putrid odour from the deposit in which the vibrios swarmed, the action must have been one of reduction, and no doubt to this fact was due the greyish coloration of the deposit. We suppose that the substances employed, however pure, always contain some trace of iron, which becomes converted into the sulphide, the black colour of which would modify the originally white deposit of insoluble tartrate and phosphate. But what is the nature of these vibrios? We have already said that we believe that they are nothing but the ordinary vibrios of putrefaction, reduced to a state of extreme tenuity by the special conditions of nutrition involved in the fermentable medium used; in a word, we think that the fermentation in question might be called putrefaction of tartrate of lime. It would be easy enough to determine this point by growing the vibrios of such fermentation in media adapted to the production of the ordinary forms of vibrio; but this is an experiment which we have not ourselves tried. One word more on the subject of these curious beings. In a great many of them there appears to be something like a clear spot, a kind of bead, at one of their extremities. This is an illusion arising from the fact that the extremity of these vibrios is curved, hanging downwards, thus causing a greater refraction at that particular point, and leading us to think that the diameter is greater at that extremity. We may easily undeceive ourselves if we watch the movements of the vibrio, when we will readily recognize the bend, especially as it is brought into the vertical plane passing over the rest of the filament. In this way we will see the bright spot, THE HEAD, disappear, and then reappear. The chief inference that it concerns us to draw from the preceding facts is one which cannot admit of doubt, and which we need not insist on any further--namely that vibrios, as met with in the fermentation of neutral tartrate of lime, are able to live and multiply when entirely deprived of air. V.--ANOTHER EXAMPLE OF LIFE WITHOUT AIR--FERMENTATION OF LACTATE OF LIME As another example of life without air, accompanied by fermentation properly so called, we may lastly cite the fermentation of lactate of lime in a mineral medium. In the experiment described in the last paragraph, it will be remembered that the ferment liquid and the germs employed in its impregnation came in contact with air, although only for a very brief time. Now, notwithstanding that we possess exact observations which prove that the diffusion of oxygen and nitrogen in a liquid absolutely deprived of air, so far from taking place rapidly, is, on the contrary, a very slow process indeed; yet we were anxious to guard the experiment that we are about to describe from the slightest possible trace of oxygen at the moment of impregnation. We employed a liquid prepared as follows: Into from 9 to 10 litres (somewhat over 2 gallons) of pure water the following salts [Footnote: Should the solution of lactate of lime be turbid, it may be clarified by filtration, after previously adding a small quantity of phosphate of ammonia, which throws down phosphate of lime. It is only after this process of clarification and filtration that the phosphates of the formula are added. The solution soon becomes turbid if left in contact with air, in consequence of the spontaneous formation of bacteria.] were introduced successively, viz: Pure lactate of lime. ... . ... . ... . ... . .. 225 grammes Phosphate of ammonia. ... . ... . ... . ... . .. 0.75 grammes Phosphate of potassium. ... . ... . ... . ... .. 0.4 grammes Sulphate of magnesium. ... . ... . ... . ... ... 0.4 grammes Sulphate of ammonia. ... . ... . ... . ... . ... 0.2 grammes (1 gramme = 15.43 grains.) [Illustration with caption: Fig. 11] On March 23rd, 1875, we filled a 6 litre (about 11 pints) flask, of the shape represented in FIG. 11, and placed it over a heater. Another flame was placed below a vessel containing the same liquid, into which the curved tube of the flask plunged. The liquids in the flask and in the basin were raised to boiling together, and kept in this condition for more than half-an-hour, so as to expel all the air held in solution. The liquid was several times forced out of the flask by the steam, and sucked back again; but the portion which re-entered the flask was always boiling. On the following day when the flask had cooled, we transferred the end of the delivery tube to a vessel full of mercury and placed the whole apparatus in an oven at a temperature varying between 25 degrees C. and 30 degrees C. (77 degrees F. and 86 degrees F.) then, after having refilled the small cylindrical tap-funnel with carbonic acid, we passed into it with all necessary precautions 10 cc. (0.35 fl. oz) of a liquid similar to that described, which had been already in active fermentation for several days out of contact with air and now swarmed with vibrios. We then turned the tap of the funnel, until only a small quantity of liquid was left, just enough to prevent the access of air. In this way the impregnation was accomplished without either the ferment-liquid or the ferment- germs having been brought in contact, even for the shortest space, with the external air. The fermentation, the occurrence of which at an earlier or later period depends for the most part on the condition of the impregnating germs, and the number introduced in the act, in this case began to manifest itself by the appearance of minute bubbles from March 29th. But not until April 9th did we observe bubbles of larger size rise to the surface. From that date onward they continued to come in increasing number, from certain points at the bottom of the flask, where a deposit of earthy phosphates existed; and at the same time the liquid, which for the first few days remained perfectly clear, began to grow turbid in consequence of the development of vibrios. It was on the same day that we first observed a deposit on the sides of carbonate of lime in crystals. It is a matter of some interest to notice here that, in the mode of procedure adopted, everything combined to prevent the interference of air. A portion of the liquid expelled at the beginning of the experiment, partly because of the increased temperature in the oven and partly also by the force of the gas, as it began to be evolved from the fermentative action, reached the surface of the mercury, where, being the most suitable medium we know for the growth of bacteria, it speedily swarmed with these organisms. [Footnote: The naturalist Cohn, of Breslau, who published an excellent work on bacteria in 1872, described, after Mayer, the composition of a liquid peculiarly adapted to the propagation of these organisms, which it would be well to compare for its utility in studies of this kind with our solution of lactate and phosphates. The following is Cohn's formula: Distilled water. ... . ... . ... . ..20 cc. (0.7 fl. oz.) Phosphate of potassium. ... . ... ...0.1 gramme (1.5 grains) Sulphate of magnesium. ... . ... . 0.1 gramme (1.5 grains) Tribasic phosphate of lime. ... ... 0.01 gramme (0.15 grain) Tartrate of ammonia. ... . ... . ... 0.2 gramme (3 grains) This liquid, the author says, has a feeble acid reaction and forms a perfectly clear solution.] In this way any passage of air, if such a thing were possible, between the mercury and the sides of the delivery-tube was altogether prevented, since the bacteria would consume every trace of oxygen which might be dissolved in the liquid lying on the surface of the mercury. Hence it is impossible to imagine that the slightest trace of oxygen could have got into the liquid in the flask. Before passing on we may remark that in this ready absorption of oxygen by bacteria we have a means of depriving fermentable liquids of every trace of that gas with a facility and success equal or even greater than by the preliminary method of boiling. Such a solution as we have described, if kept at summer heat, without any previous boiling, becomes turbid in the course of twenty-four hours from a SPONTANEOUS development of bacteria; and it is easy to prove that they absorb all the oxygen held in solution. [Footnote: On the rapid absorption of oxygen by bacteria, see also our Memoire of 1872, sur les Generations dites Spontanees, especially the note on page 78.] If we completely fill a flask of a few litres capacity (about a gallon) (Fig. 9) with the liquid described, taking care to have the delivery-tube also filled, and its opening plunged under mercury, and, forty- eight hours afterwards by means of a chloride of calcium bath, expel from the liquid on the surface of the mercury all the gas which it holds in solution, this gas, when analyzed, will be found to be composed of a mixture of nitrogen and carbonic acid gas, WITHOUT THE LEAST TRACE OF OXYGEN. Here, then, we have an excellent means of depriving the fermentable liquid of air; we simply have completely to fill a flask with the liquid, and place it in the oven, merely avoiding any addition of butyric vibrios, before the lapse of two or three days. We may wait even longer; and then, if the liquid does become impregnated spontaneously with vibrio germs, the liquid, which at first was turbid from the presence of bacteria, will become bright again, since the bacteria, when deprived of life, or, at least, of the power of moving, after they have exhausted all the oxygen in solution, will fall inert to the bottom of the vessel. On several occasions we have determined this interesting fact, which tends to prove that the butyric vibrios cannot be regarded as another form of bacteria, inasmuch as, on the hypothesis of an original relation between the two productions, butyric fermentation ought in every case to follow the growth of bacteria. We may also call attention to another striking experiment, well suited to show the effect of differences in the composition of the medium upon the propagation of microscopic beings. The fermentation which we last described commenced on March 27th and continued until May 10th; that to which we are now to refer, however, was completed in four days, the liquid employed being similar in composition and quantity to that employed in the former experiment. On April 23, 1875, we filled a flask of the same shape as that represented in Fig. 11, and of similar capacity, viz., 6 litres, with a liquid composed as described at page 69. This liquid had been previously left to itself for five days in large open flasks, in consequence of which it had developed an abundant growth of bacteria. On the fifth day a few bubbles, rising from the bottom of the vessels, at long intervals, betokened the commencement of butyric fermentation, a fact, moreover, confirmed by the microscope, in the appearance of the vibrios of this fermentation in specimens of the liquid taken from the bottom of the vessels, the middle of its mass, and even in the layer on the surface that was swarming with bacteria. We transferred the liquid so prepared to the 6 litre flask arranged over the mercury. By evening a tolerably active fermentation had begun to manifest itself. On the 24th this fermentation was proceeding with astonishing rapidity, which continued during the 25th and 26th. During the evening of the 26th it slackened, and on the 27th all signs of fermentation had ceased. This was not, as might be supposed, a sudden stoppage due to some unknown cause; the fermentation was actually completed, for when we examined the fermented liquid on the 28th we could not find the smallest quantity of lactate of lime. If the needs of industry should ever require the production of large quantities of butyric acid, there would, beyond doubt, be found in the preceding fact valuable information in devising an easy method of preparing that product in abundance. [Footnote: In what way are we to account for so great a difference between the two fermentations that we have just described? Probably it was owing to some modification effected in the medium by the previous life of the bacteria, or to the special character of the vibrios used in impregnation. Or, again, it might have been due to the action of the air, which, under the conditions of our second experiment, was not absolutely eliminated, since we took no precaution against its introduction at the moment of filling our flask, and this would tend to facilitate the multiplication of anaerobian vibrios, just as, under similar conditions, would have been the case if we had been dealing with a fermentation by ordinary yeast.] Before we go any further, let us devote some attention to the vibrios of the preceding fermentations. On May 27th, 1862, we completely filled a flask capable of holding 2.780 litres (about five pints) with the solution of lactate and phosphates. [Footnote: In this case the liquid was composed as follows: A saturated solution of lactate of lime, at a temperature of 25 degrees C. (77 degrees F.), was prepared, containing for every 1OO cc. (3 1/2 fl. oz.) 25.65 grammes (394 grains) of the lactate, C6 H5 O5 Ca O (NEW NOTATION, C6 H10 Ca O6) This solution was rendered very clear by the addition of 1 gramme of phosphate of ammonia and subsequent filtration. For a volume of 8 litres (14 pints) of this clear saturated solution we used (1 gramme = 15.43 grains): Phosphate of ammonia. ... . ... . ... . ... 2 grammes Phosphate of potassium. ... . ... . ... . ... 1 gramme Phosphate of magnesium. ... . ... . ... . ... 1 gramme Sulphate of ammonia. ... . ... . ... . ... 0.5 gramme] We refrained from impregnating it with any germs. The liquid became turbid from a development of bacteria and then underwent butyric fermentation. By June 9th the fermentation had become sufficiently active to enable us to collect in the course of twenty-four hours, over mercury, as in all our experiments, about 100 cc. (about 6 cubic inches) of gas. By June 11th, judging from the volume of gas liberated in the course of twenty-four hours, the activity of the fermentation had doubled. We examined a drop of the turbid liquid. Here are the notes accompanying the sketch (Fig. 12) as they stand in our note-book: "A swarm of vibrios, so active in their movements that the eye has great difficulty in following them. They may be seen in pairs throughout the field, apparently making efforts to separate from each other. The connection would seem to be by some invisible, gelatinous thread, which yields so far to their efforts that they succeed in breaking away from actual contact, but yet are, for a while, so far restrained that the movements of one have a visible effect on those of the other. By and by, however, we see a complete separation effected, and each moves on its separate way with an activity greater than it ever had before." [Illustration with caption: Fig. 12] One of the best methods that can be employed for the microscopical examination of these vibrios, quite out of contact with air, is the following. After butyric fermentation has been going on for several days in a flask, (Fig. 13), we connect this flask by an india-rubber tube with one of the flattened bulbs previously described, which we then place on the stage of the microscope (Fig. 13). When we wish to make an observation we close, under the mercury, at the point B, the end of the drawn- out and bent delivery-tube. The continued evolution of gas soon exerts such a pressure within the flask, that when we open the tap R, the liquid is driven into the bulb LL, until it becomes quite full and the liquid flows over into the glass V. In this manner we may bring the vibrios under observation without their coming into contact with the least trace of air, and with as much success as if the bulb, which takes the place of an object glass, had been plunged into the very centre of the flask. The movements and fissiparous multiplication of the vibrios may thus be seen in all their beauty, and it is indeed a most interesting sight. The movements do not immediately cease when the temperature is suddenly lowered, even to a considerable extent, 15 degrees C. (59 degrees F.) for example; they are only slackened. Nevertheless, it is better to observe them at the temperatures most favourable to fermentation, even in the oven where the vessels employed in the experiment are kept at a temperature between 25 degrees C. and 30 degrees C. (77 degrees F. and 86 degrees F.). [Illustration: Fig. 13] We may now continue our account of the fermentation which we were studying when we made this last digression. On June 17th that fermentation produced three times as much gas as it did on June 11th, when the residue of hydrogen, after absorption by potash, was 72.6 per cent.; whilst on the 17th it was only 49.2 per cent. Let us again discuss the microscopic aspect of the turbid liquid at this stage. Appended is the sketch we made (Fig. 14) and our notes on it: "A most beautiful object: vibrios all in motion, advancing or undulating. They have grown considerably in bulk and length since the 11th; many of them are joined together in long sinuous chains, very mobile at the articulations, visibly less active and more wavering in proportion to the number that go to form the chain, of the length of the individuals." This description is applicable to the majority of the vibrios which occur in cylindrical rods and are homogeneous in aspect. There are others, of rare occurrence in chains, which have a clear corpuscle, that is to say, a portion more refractive than other parts of the segments, at one of their extremities. Sometimes the foremost segment has the corpuscle at one end, sometimes the other. The long segments of the commoner kind attain a length of from 10 to 30 and even 45 thousandths of a millimetre. Their diameter is from 1 1/2 to 2, very rarely 3, thousandths of a millimetre. [Footnote: 1 millimetre = 0.039 inch: hence the dimensions indicated will be--length, from 0.00039 to 0.00117, or even 0.00176 in.; diameter, from 0.000058 to 0.000078, rarely 0.000117 in.--D. C. R.] [Illustration: Figure 14.] On June 28th, fermentation was quite finished; there was no longer any trace of gas, nor any lactate in solution. All the infusoria were lying motionless at the bottom of the flask. The liquid clarified by degrees, and in the course of a few days became quite bright. Here we may inquire, were these motionless infusoria, which from complete exhaustion of the lactate, the source of the carbonaceous part of their food, were now lying inert at the bottom of the fermenting vessel--were they dead beyond the power of revival? [Footnote: The carbonaceous supply, as we remarked, had failed them, and to this failure the absence of vital action, nutrition, and multiplication was attributable. The liquid, however, contained butyrate of lime, a salt possessing properties similar to those of the lactate. Why could not this salt equally well support the life of the vibrios? The explanation of the difficulty seems to us to lie simply in the fact that lactic acid produces heat by its decomposition, whilst butyric acid does not, and the vibrios seem to require heat during the chemical process of their nutrition.] The following experiment leads us to believe that they were not perfectly lifeless, and that they might behave in the same manner as the yeast of beer, which, after it has decomposed all the sugar in a fermentable liquid, is ready to revive and multiply in a fresh saccharine medium. On April 22nd, 1875, we left in the oven at a temperature of 25 degrees C. (77 degrees F.) a fermentation of lactate of lime that had been completed. The delivery tube of the flask A, (Fig. 15), in which it had taken place, had never been withdrawn from under the mercury. We kept the liquid under observation daily, and saw it gradually become brighter; this went on for fifteen days. We then filled a similar flask, B, with the solution of lactate, which we boiled, not only to kill the germs of vibrios which the liquid might contain, but also to expel the air that it held in solution. When the flask, B, had cooled, we connected the two flasks, avoiding the introduction of air, [Footnote: To do this it is sufficient, first, to fill the curved ends of the stop-cocked tubes of the flasks, as well as the india-rubber tube C C which connects them, with boiling water that contains no air.] after having slightly shaken the flask, A, to stir up the deposit at the bottom. There was then a pressure due to carbonic acid at the end of the delivery tube of this latter flask, at the point A, so that on opening the taps R and S, the deposit at the bottom of flask A was driven over into flask B, which in consequence was impregnated with the deposit of a fermentation that had been completed fifteen days before. Two days after impregnation the flask B began to show signs of fermentation. It follows that the deposit of vibrios of a completed butyric fermentation may be kept, at least for a certain time, without losing the power of causing fementation. It furnishes a butyric ferment, capable of revival and action in a suitable fresh fermentable medium. [Illustration: Fig. 15] The reader who has attentively studied the facts which we have placed before him cannot, in our opinion, entertain the least doubt on the subject of the possible multiplication of the vibrios of a fermentation of lactate of lime out of contact with atmospheric oxygen. If fresh proofs of this important proposition were necessary, they might be found in the following observations, from which it may be inferred that atmospheric oxygen is capable of suddenly checking a fermentation produced by butyric vibrios, and rendering them absolutely motionless, so that it cannot be necessary to enable them to live. On May 7th, 1862, we placed in the oven a flask holding 2.580 litres (4 1/2 pints), and filled with the solution of lactate of lime and phosphates, which we had impregnated on the 9th with two drops of a liquid in butyric fermentation. In the course of a few days fermentation declared itself: on the 18th it was active; on the 30th it was very active. On June 1st it yielded hourly 35 cc. (2.3 cubic inches) of gas, containing ten per cent, of hydrogen. On the 2nd we began the study of the action of air on the vibrios of this fermentation. To do this we cut off the delivery-tube on a level with its point of junction to the flask, then with a 50 cc. pipette we took out that quantity (1 3/4 fl. oz.) of liquid which was, of course, replaced at once by air. We then reversed the flask with the opening under the mercury, and shook it every ten minutes for more than an hour. Wishing to make sure, to begin with, that the oxygen had been absorbed we connected under the mercury the beak of the flask by means of a thin india-rubber tube filled with water, with a small flask, the neck of which had been drawn out and was filled with water; we then raised the large flask with the smaller kept above it. A Mohr's clip, which closed the india-rubber tube, and which we then opened, permitted the water contained in the small flask to pass into the large one, whilst the gas, on the contrary, passed upwards from the large flask into the small one. We analyzed the gas immediately, and found that, allowing for the carbonic acid and hydrogen, it did not contain more than 14.2 per cent. of oxygen, which corresponds to an absorption of 6.6 cc., or of 3.3 cc. (0.2 cubic inch) of oxygen for the 50 cc. (3.05 cubic inches) of air employed. Lastly, we again established connection by an india- rubber tube between the flasks, after having seen by microscopical examination that the movements of the vibrios were very languid. Fermentation had become less vigorous without having actually ceased, no doubt because some portions of the liquid had not been brought into contact with the atmospheric oxygen, in spite of the prolonged shaking that the flask had undergone after the introduction of the air. Whatever the cause might have been, the significance of the phenomenon is not doubtful. To assure ourselves further of the effect of air on the vibrios, we half filled two test tubes with the fermenting liquid taken from another fermentation which had also attained its maximum of intensity, into one of which we passed a current of air, into the other carbonic acid gas. In the course of half an hour, all the vibrios in the aerated tube were dead, or at least motionless, and fermentation had ceased. In the other tube, after three hours' exposure to the effects of the carbonic acid gas, the vibrios were still very active, and fermentation was going on. There is a most simple method of observing the deadly effect of atmospheric air upon vibrios. We have seen in the microscopical examination made by means of the apparatus represented in FIG. 13, how remarkable were the movements of the vibrios when absolutely deprived of air, and how easy it was to discern them. We will repeat this observation, and at the same time make a comparative study of the same liquid under the microscope in the ordinary way, that is to say, by placing a drop of the liquid on an object-glass, and covering it with a thin glass slip, a method which must necessarily bring the drop into contact with air, if only for a moment. It is surprising what a remarkable difference is observed immediately between the movements of the vibrios in the bulb and those under the glass. In the case of the latter, we generally see all movement at once cease near the edges of the glass, where the drop of liquid is in direct contact with the air; the movements continue for a longer or shorter time about the centre, in proportion as the air is more or less intercepted by the vibrios at the circumference of the liquid. It does not require much skill in experiments of this kind to enable one to see plainly that immediately after the glass has been placed on the drop, which has been affected all over by atmospheric air, the whole of the vibrios seem to languish and to manifest symptoms of illness--we can think of no better expression to explain what we see taking place--and that they gradually recover their activity about the centre, in proportion as they find themselves in a part of the medium that is less affected by the presence of oxygen. Some of the most curious facts are to be found in connection with an observation, the correlative and inverse of the foregoing, on the ordinary aerobian bacteria. If we examine below the microscope a drop of liquid full of these organisms under a coverslip, we very soon observe a cessation of motion in all the bacteria which lie in the central portion of the liquid, where the oxygen rapidly disappears to supply the necessities of the bacteria existing there; whilst, on the other hand, near the edges of the cover-glass the movements are very active, in consequence of the constant supply of air. In spite of the speedy death of the bacteria beneath the centre of the glass, we see life prolonged there if by chance a bubble of air has been enclosed. All round this bubble a vast number of bacteria collect in a thick, moving circle, but as soon as all the oxygen of the bubble has been absorbed they fall apparently lifeless, and are scattered by the movement of the liquid. [Footnote: We find this fact, which we published as long ago as 1863, confirmed in a work of H. Hoffman's, published in 1861 under the title of Memoire sur les bacteries, which has appeared in French (Annales des Sciences naturelles, 5th series, vol. ix.). On this subject we may cite an observation that has not yet been published. Aerobian bacteria lose all power of movement when suddenly plunged into carbonic acid gas; they recover it, however, as if they had only been suffering from anaesthesia, as soon as they are brought into the air again.] We may here be permitted to add, as a purely historical matter, that it was these two observations just described, made successively one day in 1861, on vibrios and bacteria, that first suggested to us the idea of the possibility of life without air, and caused us to think that the vibrios which we met so frequently in our lactic fermentations must be the true butyric ferment. We may pause to consider an interesting question in reference to the two characters under which vibrios appear in butyric fermentations. What is the reason that some vibrios exhibit refractive corpuscles, generally of a lenticular form, such as we see in FIG. 14. We are strongly inclined to believe that these corpuscles have to do with a special mode of reproduction in the vibrios, common alike to the anaerobian forms which we are studying, and the ordinary aerobian forms in which also the corpuscles of which we are speaking may occur. The explanation of the phenomenon, from our point of view, would be that, after a certain number of fisiparous generations, and under the influence of variations in the composition of the medium, which is constantly changing through fermentation as well as through the active life of the vibrios themselves, cysts, which are simply the refractive corpuscles, form along them at different points. From these gemmules we have ultimately produced vibrios, ready to reproduce others by the process of transverse division for a certain time, to be themselves encysted, later on. Various observations incline us to believe that, in their ordinary form of minute, soft, exuberant rods, the vibrios perish when submitted to desiccation, but when they occur in corpuscular or encysted form they possess unusual powers of resistance and may be brought to the state of dry dust and be wafted about by winds. None of the matter which surrounds the corpuscle or cyst seems to take part in the preservation of the germ, when the cyst is formed, for it is all re-absorbed, gradually leaving the cyst bare. The cysts appear as masses of corpuscles, in which the most practiced eye cannot detect anything of an organic nature, or anything to remind one of the vibrios which produced them; nevertheless, these minute bodies are endowed with a latent vital action, and only await favourable conditions to develop long rods of vibrios. We are not, it is true, in a position to adduce any very forcible proofs in support of these opinions. They have been suggested to us by experiments, none of which, however, have been absolutely decisive in their favour. We may cite one of our observations on this subject. In a fermentation of glycerine in a mineral medium--the glycerine was fermenting under the influence of butyric vibrios--after we had determined the, we may say, exclusive presence of lenticular vibrios, with refractive corpuscles, we observed the fermentation, which for some unknown reason had been very languid, suddenly become extremely active, but now through the influence of the ordinary vibrios. The gemmules with brilliant corpuscles had almost disappeared; we could see but very few, and those now consisted of the refractive bodies alone, the bulk of the vibrios accompanying them having undergone some process of re-absorption. Another observation which still more closely accords with this hypothesis is given in our work on silk-worm disease (vol. 1, p. 256). We there demonstrated that, when we place in water some of the dust formed of desiccated vibrios, containing a host of these refractive corpuscles, in the course of a very few hours large vibrios appear, well-developed rods fully grown, in which the brilliant points are absent; whilst in the water no process of development from smaller vibrios is to be discerned, a fact which seems to show that the former had issued fully grown from the refractive corpuscles, just as we see colpoda issue with their adult aspect from the dust of their cysts. This observation, we may remark, furnishes one of the best proofs that can be adduced against the spontaneous generation of vibrios or bacteria, since it is probable that the same observation applies to bacteria. It is true that we cannot say of mere points of dust examined under the microscope, that one particular germ belongs to vibrio, another to bacterium; but how is it possible to doubt that the vibrios issue, as we see them, from an ovum of some kind, a cyst, or germ, of determinate character, when, after having placed some of those indeterminate motes of dust into clean water, we suddenly see, after an interval of not more than one or two hours, an adult vibrio crossing the field of the microscope, without our having been able to detect any intermediate state between its birth and adolescence? [Illustration: Fig. 16] It is a question whether differences in the aspect and nature of vibrios, which depend upon their more or less advanced age, or are occasioned by the influence of certain conditions on the medium in which they propagate, do not bring about corresponding changes in the course of the fermentation and the nature of its products. Judging at least from the variations in the proportions of hydrogen, and carbonic acid gas produced in butyric fermentations, we are inclined to think that this must be the case; nay, more, we find that hydrogen is not even a constant product in these fermentations. We have met with butyric fermentations of lactate of lime which did not yield the minutest trace of hydrogen, or anything besides carbonic acid. Fig. 16 represents the vibrios which we observed in a fermentation of this kind. They present no special features. Butyl alcohol is, according to our observations, an ordinary product, although it varies and is by no means a necessary concomitant of these fermentations. It might be supposed, since butylic alcohol may be produced and hydrogen be in deficit, that the proportion of the former of these products would attain its maximum when the latter assumed a minimum. This, however, is by no means the case; even in those few fermentations that we have met with in which hydrogen was absent, there was no formation of butylic alcohol. From a consideration of all the facts detailed in this section we can have no hesitation in concluding that, on the one hand, in cases of butyric fermentation, the vibrios which abound in them and constitute their ferment, live without air or free oxygen; and that, on the other hand, the presence of gaseous oxygen operates prejudicially against the movements and activity of those vibrios. But how does it follow that the presence of minute quantities of air brought into contact with a liquid undergoing butyric fermention would prevent the continuance of that fermentation or even exercise any check upon it? We have not made any direct experiments upon this subject; but we should not be surprised to find that, so far from hindering, air may, under such circumstances, facilitate the propagation of the vibrios and accelerate fermentation. This is exactly what happens in the case of yeast. But how could we reconcile this, supposing it were proved to be the case, with the fact just insisted on as to the danger of bringing the butyric vibrios into contact with air? It may be possible that LIFE WITHOUT AIR results from habit, whilst DEATH THROUGH AIR may be brought about by a sudden change in the conditions of the existence of the vibrios. The following remarkable experiment is well-known: A bird is placed in a glass jar of one or two litres (60 to 120 cubic inches) in capacity which is then closed. After a time the creature shows every sign of intense uneasiness and asphyxia long before it dies; a similar bird of the same size is introduced into the jar; the death of the latter takes place instanteously, whilst the life of the former may still be prolonged under these conditions for a considerable time, and there is no, difficulty even in restoring the bird to perfect health by taking it out of the jar. It seems impossible to deny that we have here a case of the adaptation of an organism to the gradual contamination of the medium; and so it may likewise happen that the anaerobian vibrios of a butyric fermentation, which develop and multiply absolutely without free oxygen, perish immediately when suddenly taken out of their airless medium, and that the result might be different if they had been gradually brought under the action of air in small quantities at a time. We are compelled here to admit that vibrios frequently abound in liquids exposed to the air, and that they appropriate the atmospheric oxygen, and could not withstand a sudden removal from its influence. Must we, then, believe that such vibrios are absolutely different from those of butyric fermentations? It would, perhaps, be more natural to admit that in the one case there is an adaptation to life with air, and in the other case an adaptation to life without air; each of the varieties perishing when suddenly transferred from its habitual condition to that of the other, whilst by a series of progressive changes one might be modified into the other. [Footnote: These doubts might be easily removed by putting the matter to the test of direct experiment.] We know that in the case of alcoholic ferments, although these can actually live without air, propagation is wonderfully assisted by the presence of minute quantities of air; and certain experiments which we have not yet published lead us to believe that, after having lived without air, they cannot be suddenly exposed with impunity to the influence of large quantities of oxygen. We must not forget, however, that aerobian torulae and anaerobian ferments present an example of organisms apparently identical, in which, however, we have not yet been able to discover any ties of a common origin. Hence we are forced to regard them as a distinct species; and so it is possible that there may likewise be aerobian and anaerobian vibrios without any transformation of the one into the other. The question has been raised whether vibrios, especially those which we have shown to be the ferment of butyric and many other fermentations, are in their nature, animal or vegetable. M. Ch. Robin attaches great importance to the solution of this question, of which he speaks as follows: [Footnote: ROBIN, Sur la nature des fermentations, &c. (Journal de l'Academie et de la Physiologie, July and August, 1875, P. 386).] "The determination of the nature, whether animal or vegetable, of organisms, either as a whole or in respect to their anatomical parts, assimilative or reproductive, is a problem which has been capable of solution for a quarter of a century. The method has been brought to a state of remarkable precision, experimentally, as well as in its theoretical aspects, since those who devote their attention to the organic sciences consider it indispensable in every observation and experiment to determine accurately, before anything else, whether the object of their study is animal or vegetable in its nature, whether adult or otherwise. To neglect this is as serious an omission for such students as for chemists would be the neglecting to determine whether it is nitrogen or hydrogen, urea or stearine, that has been extracted from a tissue, or which it is whose combinations they are studying in this or that chemical operation. Now, scarcely any one of those who study fermentations, properly so-called, and putrefactions, ever pay any attention to the preceding data. ... Among the observers to whom I allude, even M. Pasteur is to be found, who, even in his most recent communications, omits to state definitely what is the nature of many of the ferments which he has studied, with the exception, however, of those which belong to the cryptogamic group called torulaceae. Various passages in his work seem to show that he considers the cryptogamic organisms called bacteria, as well as those known as vibrios, as belonging to the animal kingdom (see Bulletin de l'Academie de Medecine, Paris, 1875, pp. 249, 251, especially 256, 266, 267, 289, and 290). These would be very different, at least physiologically, the former being anaerobian, that is to say, requiring no air to enable them to live, and being killed by oxygen, should it be dissolved in the liquid to any considerable extent." We are unable to see the matter in the same light as our learned colleague does; to our thinking, we should be labouring under a great delusion were we to suppose "that it is quite as serious an omission not to determine the animal or vegetable nature of a ferment as it would be to confound nitrogen with hydrogen or urea with stearine." The importance of the solutions of disputed questions often depends on the point of view from which these are regarded. As far as the result of our labours is concerned, we devoted our attention to these two questions exclusively: 1. Is the ferment, in every fermentation properly so called, an organized being? 2. Can this organized being live without air? Now, what bearing can the question of the animal or vegetable nature of the ferment, of the organized being, have upon the investigation of these two problems? In studying butyric fermentation, for example, we endeavoured to establish these two fundamental points; 1. The BUTYRIC FERMENT IS A VIBRIO. 2. THIS VIBRIO MAY DISPENSE WITH AIR IN ITS LIFE, AND, AS A MATTER OF FACT, DOES DISPENSE WITH IT IN THE ACT OF PRODUCING BUTYRIC FERMENTATION. We did not consider it at all necessary to pronounce any opinion as to the animal or vegetable nature of this organism, and, even up to the present moment, the idea that vibrio is an animal and not a plant is in our minds, a matter of sentiment rather than of conviction. M. Robin, however, would have no difficulty in determining the limits of the two kingdoms. According to him, "every variety of cellulose is, we may say, insoluble in ammonia, as also are the reproductive elements of plants, whether male or female. Whatever phase of evolution the elements which reproduce a new individual may have reached, treatment with this reagent, either cold or raised to boiling, leaves them absolutely intact under the eyes of the observer, except that their contents, from being partially dissolved, become more transparent. Every vegetable whether microscopic or not, every mycelium and every spore, thus preserves in its entirety its special characteristics of form, volume and structural arrangements; whilst in the case of microscopic animals, or the ova and microscopic embryos of different members of the animal kingdom, the very opposite is the case." We should be glad to learn that the employment of a drop of ammonia would enable us to pronounce an opinion with this degree of confidence on the nature of the lowest microscopic beings; but is M. Robin absolutely correct in his assumptions? That gentleman himself remarks that spermatozoa, which belong to animal organisms, are insoluble in ammonia, the effect of which is merely to make them paler. If a difference of action in certain reagents, in ammonia, for example, were sufficient to determine the limits of the animal and vegetable kingdoms, might we not argue that there must be a very great and natural difference between moulds and bacteria, inasmuch as the presence of a small quantity of acid in the nutritive medium facilitates the growth and propagation of the former, whilst it is able to prevent the life of bacteria and vibrios? Although as is well known, movement is not an exclusive characteristic of animals, yet we have always been inclined to regard vibrios as animals, on account of the peculiar character of their movements. How greatly they differ in this respect from the diatomacae, for example! When the vibrio encounters an obstacle it turns, or after assuring itself by some visual effort or other that it cannot overcome it, it retraces its steps. The colpoda--undoubted infusoria--behave in an exactly similar manner. It is true one may argue that the zoospores of certain cryptogamia exhibit similar movements; but do not these zoospores possess as much of an animal nature as do the spermatozoa? As far as bacteria are concerned, when, as already remarked, we see them crowd round a bubble of air in a liquid to prolong their life, oxygen having failed them everywhere else, how can we avoid believing that they are animated by an instinct for life, of the same kind that we find in animals? M. Robin seems to us to be wrong in supposing that it is possible to draw any absolute line of separation between the animal and vegetable kingdoms. The settlement of this line however, we repeat again, no matter what it may be, has no serious bearing upon the questions that have been the subject of our researches. In like manner the difficulty which M. Robin has raised in objecting to the employment of the word GERM, when we cannot specify whether the nature of that germ is animal or vegetable, is in many respects an unnecessary one. In all the questions which we have discussed, whether we were speaking of fermentation or spontaneous generation, the word GERM has been used in the sense of ORIGIN OF LIVING ORGANISM. If Liebig, for example, said of an albuminous substance that it gave birth to ferment, could we contradict him more plainly than by replying "No; ferment is an organized being, the germ of which is always present, and the albuminous substance merely serves by its occurrence to nourish the germ and its successive generations"? In our Memoir of 1862, on so-called SPONTANEOUS generations, would it not have been an entire mistake to have attempted to assign specific names to the microscopic organisms which we met with in the course of our observations? Not only would we have met with extreme difficulty in the attempt, arising from the state of extreme confusion which even in the present day exists in the classification and nomenclature of these microscopic organisms, but we should have been forced to sacrifice clearness in our work besides; at all events, we should have wandered from our principal object, which was the determination of the presence or absence of life in general, and had nothing to do with the manifestation of a particular kind of life in this or that species, animal or vegetable. Thus we have systematically employed the vaguest nomenclature, such as mucors, torulae, bacteria, and vibrios. There was nothing arbitrary in our doing this, whereas there is much that is arbitrary in adopting a definite system of nomenclature, and applying it to organisms but imperfectly known, the differences or resemblances between which are only recognizable through certain characteristics, the true signification of which is obscure. Take, for example, the extensive array of widely different systems which have been invented during the last few years for the species of the genera bacterium and vibrio in the works of Cohn, H. Hoffmann, Hallier, and Billroth. The confusion which prevails here is very great, although we do not of course by any means place these different works on the same footing as regards their respective merits. M. Robin is, however, right in recognizing the impossibility of maintaining in the present day, as he formerly did, "That fermentation is an exterior phenomenon, going on outside cryptogamic cells, a phenomenon of contact. It is probably," he adds, "an interior and molecular action at work in the innermost recesses of the substance of each cell." From the day when we first proved that it is possible for all organized ferments, properly so called, to spring up and multiply from their respective germs, sown, whether consciously or by accident, in a mineral medium free from organic and nitrogenous matters other than ammonia, in which medium the fermentable matter alone is adapted to provide the ferment with whatever carbon enters into its composition, from that time forward the theories of Liebig, as well of Berzelius, which M. Robin formerly defended, have had to give place to others more in harmony with facts. We trust that the day will come when M. Robin will likewise acknowledge that he has been in error on the subject of the doctrine of spontaneous generation, which he continues to affirm, without adducing any direct proofs in support of it, at the end of the article to which we have been here replying. We have devoted the greater part of this chapter to the establishing with all possible exactness the extremely important physiological fact of life without air, and its correlation to the phenomena of fermentations properly so called--that is to say, of those which are due to the presence of microscopic cellular organisms. This is the chief basis of the new theory that we propose for the explanation of these phenomena. The details into which we have entered were indispensable on account of the novelty of the subject no less than on account of the necessity we were under of combating the criticisms of the two German naturalists, Drs. Oscar Brefeld and Traube, whose works had cast some doubts on the correctness of the facts upon which we had based the preceding propositions. We have much pleasure in adding that at the very moment we were revising the proofs of this chapter, we received from M. Brefeld an essay, dated Berlin, January, 1876, in which, after describing his later experimental researches, he owns with praiseworthy frankness that Dr. Traube and he were both of them mistaken. Life without air is now a proposition which he accepts as perfectly demonstrated. He has witnessed it in the case of Mucor racemosus and has also verified it in the case of yeast. "If," he says, "after the results of my previous researches, which I conducted with all possible exactness, I was inclined to consider Pasteur's assertion as inaccurate and to attack them, I have no hesitation now in recognizing them as true, and in proclaiming the service which Pasteur has rendered to science in being the first to indicate the exact relation of things in the phenomenon of fermentation." In his later researches, Dr. Brefeld has adopted the method which we have long employed for demonstrating the life and multiplication of butyric vibrios in the entire absence of air, as well as the method of conducting growths in mineral media associated with fermentable substance. We need not pause to consider certain other secondary criticisms of Dr. Brefeld. A perusal of the present work will, we trust, convince him that they are based on no surer foundation than were his former criticisms. To bring one's self to believe in a truth that has just dawned upon one is the first step towards progress; to persuade others is the second. There is a third step, less useful perhaps, but highly gratifying nevertheless, which is, to convince one's opponents. We therefore, have experienced great satisfaction in learning that we have won over to our ideas an observer of singular ability, on a subject which is of the utmost importance to the physiology of cells. VI. REPLY TO THE CRITICAL OBSERVATIONS OF LIEBIG, PUBLISHED IN 1870. [Footnote: LIEBIG, Sur la fermentation et la source de la force musculaire (Annales de Chimie et de Physique, 4th series, t. xxiii., p. 5, 1870).] In the Memoir which we published, in 1860, on alcoholic fermentation, and in several subsequent works, we were led to a different conclusion on the causes of this very remarkable phenomenon from that which Liebig had adopted. The opinions of Mitscherlich and Berzelius had ceased to be tenable in the presence of the new facts which we had brought to light. From that time we felt sure that the celebrated chemist of Munich had adopted our conclusions, from the fact that he remained silent on this question for a long time, although it had been until then the constant subject of his study, as is shown by all his works. Suddenly there appeared in the Annales de Chimie et de Physique a long essay, reproduced from a lecture delivered by him before the Academy of Bavaria in 1868 and 1869. In this Liebig again maintained, not, however, without certain modifications, the views which he had expressed in his former publications, and disputed the correctness of the principal facts enunciated in our Memoir of 1860, on which were based the arguments against his theory. "I had admitted," he says, "that the resolution of fermentable matter into compounds of a simpler kind must be traced to some process of decomposition taking place in the ferment, and that the action of this same ferment on the fermentable matter must continue or cease according to the prolongation or cessation of the alteration produced in the ferment. The molecular change in the sugar, would, consequently, be brought about by the destruction or modification of one or more of the component parts of the ferment, and could only take place through the contact of the two substances. M. Pasteur regards fermentation in the following light: The chemical action of fermentation is essentially a phenomenon correlative with a vital action, beginning and ending with it. He believes that alcoholic fermentation can never occur without the simultaneous occurrence of organization, development, and multiplication of globules, or continuous life, carried on from globules already formed. But the idea that the decomposition of sugar during fermentation is due to the development of the cellules of the ferment, is in contradiction with the fact that the ferment is able to bring about the fermentation of a pure solution of sugar. The greater part of the ferment is composed of a substance that is rich in nitrogen and contains sulphur. It contains, moreover, an appreciable quantity of phosphates, hence it is difficult to conceive how, in the absence of these elements in a pure solution of sugar undergoing fermentation, the number of cells is capable of any increase." Notwithstanding Liebig's belief to the contrary, the idea that the decomposition of sugar during fermentation is intimately connected with a development of the cellules of the ferment, or a prolongation of the life of cellules already formed, is in no way opposed to the fact that the ferment is capable of bringing about the fermentation of a pure solution of sugar. It is manifest to any one who has studied such fermentation with the microscope, even in those cases where the sweetened water has been absolutely pure, that ferment-cells do multiply, the reason being that the cells carry with them all the food-supplies necessary for the life of the ferment. They may be observed budding, at least many of them, and there can be no doubt that those which do not bud still continue to live; life has other ways of manifesting itself besides development and cell-proliferation. If we refer to the figures on page 81 of our Memoir of 1860, Experiments D, E, F, H, I, we shall see that the weight of yeast, in the case of the fermentation of a pure solution of sugar, undergoes a considerable increase, even without taking into account the fact that the sugared water gains from the yeast certain soluble parts, since in the experiments just mentioned, the weights of solid yeast, washed and dried at 100 degrees C. (212 degrees F.), are much greater than those of the raw yeast employed, dried at the same temperature. In these experiments we employed the following weights of yeast, expressed in grammes (1 gramme=15.43 grains): (1) 2.313 (2) 2.626 (3) 1.198 (4) 0.699 (5) 0.326 (6) 0.476 which became, after fermentation, we repeat, without taking into account the matters which the sugared water gained from the yeast: grammes. grains. (1) 2.486 Increase 0.173 = 2.65 (2) 2.963 Increase 0.337 = 5.16 (3) 1.700 Increase 0.502 = 7.7 (4) 0.712 Increase 0.013 = 0.2 (5) 0.325 Increase 0.009 = 0.14 (6) 0.590 Increase 0.114 = 1.75 Have we not in this marked increase in weight a proof of life, or, to adopt an expression which may be preferred, a proof of a profound chemical work of nutrition and assimilation? We may cite on this subject one of our earlier experiments, which is to be found in the Comptes rendus de l'Academie for the year 1857, and which clearly shows the great influence exerted on fermentation by the soluble portion that the sugared water takes up from the globules of ferment: "We take two equal quantities of fresh yeast that have been washed very freely. One of these we cause to ferment in water containing nothing but sugar, and, after removing from the other all its soluble particles--by boiling it in an excess of water and then filtering it to separate the globules--we add to the filtered liquid as much sugar as was used in the first case along with a mere trace of fresh yeast insufficient, as far as its weight is concerned, to affect the results of our experiment. The globules which we have sown bud, the liquid becomes turbid, a deposit of yeast gradually forms, and, side by side with these appearances, the decomposition of the sugar is effected, and in the course of a few hours manifests itself clearly. These results are such as we might have anticipated. The following fact, however, is of importance. In effecting by these means the organization into globules of the soluble part of the yeast that we used in the second case, we find that a considerable quantity of sugar is decomposed. The following are the results of our experiment; 5 grammes of yeast caused the fermentation of 12.9 grammes of sugar in six days, at the end of which time it was exhausted. The soluble portion of a like quantity of 5 grammes of the same yeast caused the fermentation of 10 grammes of sugar in nine days, after which the yeast developed by the sowing was likewise exhausted." How is it possible to maintain that, in the fermentation of water containing nothing but sugar, the soluble portion of the yeast does not act, either in the production of new globules or the perfection of old ones, when we see, in the preceding experiment, that after this nitrogenous and mineral portion has been removed by boiling, it immediately serves for the production of new globules, which, under the influence of the sowing of a mere trace of globules, causes the fermentation of so much sugar? [Footnote: It is important that we should here remark that, in the fermentation of pure solution of sugar by means of yeast, the oxygen originally dissolved in the water, as well as that appropriated by the globules of yeast in their contact with air, has a considerable effect on the activity of the fermentation. As a matter of fact, if we pass a strong current of carbonic acid through the sugared water and the water in which the yeast has been treated, the fermentation will be rendered extremely sluggish, and the few new cells of yeast which form will assume strange and abnormal aspects. Indeed this might have been expected, for we have seen that yeast, when somewhat old, is incapable of development or of causing fermentation even in a fermentable medium containing all the nutritive principles of yeast if the liquid has been deprived of air; much more should we expect this to be the case in pure sugared water, likewise deprived of air.] In short, Liebig is not justified in saying that the solution of pure sugar, caused to ferment by means of yeast, contains none of the elements needed for the growth of yeast, neither nitrogen, sulphur nor phosphorus, and that, consequently, it should not be possible, by our theory, for the sugar to ferment. On the contrary, the solution does contain all these elements, as a consequence of the introduction and presence of the yeast. Let us proceed without examination of Liebig's criticisms: "To this," he goes on to say, "must be added the decomposing action which yeast exercises on a great number of substances, and which resembles that which sugar undergoes. I have shown that malate of lime ferments readily enough through the action of yeast, and that it splits up into three other calcareous salts, namely, the acetate, the carbonate and the succinate. If the action of yeast consists in its increase and multiplication, it is difficult to conceive this action in the case of malate of lime and other calcareous salts of vegetable acids." This statement, with all due deference to the opinion of our illustrious critic, is by no means correct. Yeast has no action on malate of lime, or on other calcareous salts formed by vegetable acids. Liebig had previously, much to his own satisfaction, brought forward urea as being capable of transformation into carbonate of ammonia during alcoholic fermentation in contact with yeast. This has been proved to be erroneous. It is an error of the same kind that Liebig again brings forward here. In the fermentation of which he speaks (that of malate of lime), certain spontaneous ferments are produced, the germs of which are associated with the yeast, and develop in the mixture of yeast and malate. The yeast merely serves as a source of food for these new ferments without taking any direct part in the fermentations of which we are speaking. Our researches leave no doubt on this point, as is evident from the observations on the fermentation of tartrate of lime previously given. It is true that there are circumstances under which yeast brings about modifications in different substances. Doebereiner and, Mitscherlich, more especially, have shown that yeast imparts to water a soluble material, which liquefies cane-sugar and produces inversion in it by causing it to take up the elements of water, just as diastase behaves to starch or emulsin to amygdalin. M. Berthelot also has shown that this substance may be isolated by precipitating it with alcohol, in the same way as diastase is precipitated from its solutions. [Footnote: DOEBEREINER, Journal de Chimie de Schweigger, vol. xii., p. 129, and Journal de Pharmacie, vol. i., p. 342. MITSCHERLICH, Monatsberichte d. Kon. Preuss. Akad. d. Wissen, eu Berlin, and Rapports annuels da Berzelius, Paris, 1843, 3rd year. On the occasion of a communication on the inversion of cane-sugar by H. Rose, published in 1840, M. Mitscherlich observed: "The inversion of cane-sugar in alcoholic fermentation is not due to the globules of yeast, but to a soluble matter in the water with which they mix. The liquid obtained by straining off the ferment on a filter paper possesses the property of converting cane-sugar into uncrystallizable sugar." BERTHELOT, Comptes rendus de l'Academie. Meeting of May 28th, 1860, M. Berthelot confirms the preceding experiment of Mitscherlich, and proves, moreover, that the soluble matter of which the author speaks may be precipitated with alcohol without losing its invertive power. M. Bechamp has applied Mitscherlich's observation, concerning the soluble fermentative part of yeast, to fungoid growths, and has made the interesting discovery that fungoid growths, like yeast, yield to water a substance that inverts sugar. When the production of fungoid growths is prevented by means of an antiseptic, the inversion of sugar does not take place. We may here say a few words respecting M. Bechamp's claim to priority of discovery. It is a well-known fact that we were the first to demonstrate that living ferments might be completely developed if their germs were placed in pure water together with sugar, ammonia, and phosphates. Relying on this established fact, that moulds are capable of development in sweetened water in which, according to M. Bechamp, they invert the sugar, our author asserts that he has proved that "living organized ferments may originate in media which contain no albuminous substances." (See Comptes rendus, vol. ixxv., p. 1519.) To be logical, M. Bechamp might say that he has proved that certain moulds originate in pure sweetened water without nitrogen or phosphates or other mineral elements, for such a deduction might very well be drawn from his work, in which we do not find the least expression of astonishment at the possibility of moulds developing in pure water containing nothing but sugar without other mineral or organic principles. M. Bechamp's first note on the inversion of sugar was published in 1855. In it we find nothing relating to the influence of moulds. His second, in which that influence is noticed, was published in January, 1858, that is, subsequently to our work on lactic fermentation, which appeared in November, 1857. In that work we established for the first time that the lactic ferment is a living, organized being, that albuminous substances have no share in the production of fermentation, and that they only serve as the food of the ferment. M. Bechamp's note was even subsequent to our first work on alcoholic fermentation, which appeared on December 21st, 1857. It is since the appearance of these two works of ours that the preponderating influence of the life of microscopic organism in the phenomena of fermentation has been better understood. Immediately after their appearance M. Bechamp, who from 1855 had made no observation on the action of fungoid growths on sugar, although he had remarked their presence, modified his former conclusions. (Comptes rendus, January 4th, 1858.)] These are remarkable facts, which are, however, at present but vaguely connected with the alcoholic fermentation of sugar by means of yeast. The researches in which we have proved the existence of special forms of living ferments in many fermentations, which one might have supposed to have been produced by simple contact action, had established beyond doubt the existence of profound differences between those fermentations, which we have distinguished as fermentations proper, and the phenomena connected with soluble substances. The more we advance, the more clearly we are able to detect these differences. M. Dumas has insisted on the fact that the ferments of fermentation proper multiply and reproduce themselves in the process whilst the others are destroyed. [Footnote: "There are two classes of ferments; the first, of which the yeast of beer may be taken as the type, perpetuate and renew themselves if they can find in the liquid in which they produce fermentation food enough for their wants; the second, of which diastase is the type, always sacrifice themselves in the exercise of their activity." (DUMAS, Comptes rendus de l'Academie, t. lxxv., p. 277, 1872.)] Still more recently M. Muntz has shown that chloroform prevents fermentations proper, but does not interfere with the action of diastase (Comptes rendus, 1875). M. Bouchardat had already established the fact that hydrocyanic acid, salts of mercury, ether, alcohol, creosote, and the oils of turpentine, lemon, cloves, and mustard destroy or check alcoholic fermentations, whilst in no way interfering with the glucoside fermentations (Annales de Chimie et de Physique. 3rd series, t. xiv., 1845). We may add in praise of M. Bouchardat's sagacity, that that skilful observer has always considered these results as a proof that alcoholic fermentation is dependent on the life of the yeast-cell, and that a distinction should be made between the two orders of fermentation. M. Paul Bert, in his remarkable studies on the influence of barometric pressure on the phenomena of life, has recognized the fact that compressed oxygen is fatal to certain ferments, whilst under similar conditions it does not interfere with the action of those substances classed under the name of SOLUBLE FERMENTS, such as diastase (the ferment which inverts cane sugar) emulsin and others. During their stay in compressed air, ferments proper ceased their activity, nor did they resume it, even after exposure to air at ordinary pressures, provided the access of germs was prevented. We now come to Liebig's principal objection, with which he concludes his ingenious argument, and to which no less than eight or nine pages of the Annales are devoted. Our author takes up the question of the possibility of causing yeast to grow in sweetened water, to which a salt of ammonia and some yeast-ash have been added--a fact which is evidently incompatible with his theory that a ferment is always an albuminous substance on its way to decomposition. In this case the albuminous substance does not exist; we have only the mineral substances which will serve to produce it. We know that Liebig regarded yeast, and, generally speaking, any ferment whatever, as being a nitrogenous, albuminous substance which, in the same way as emulsin, for example, possesses the power of bringing about certain chemical decompositions. He connected fermentation with the easy decomposition of that albuminous substance, and imagined that the phenomenon occurred in the following manner: "The albuminous substance on its way to decomposition possesses the power of communicating to certain other bodies that same state of mobility by which its own atoms are already affected; and through its contact with other bodies it imparts to them the power of decomposing or of entering into other combinations." Here Liebig failed to perceive that the ferment, in its capacity of a living organism, had anything to do with the fermentation. This theory dates back as far as 1843. In 1846 Messrs. Boutron and Fremy, in a Memoir on lactic fermentation, published in the Annales de Chimie et de Physique, strained the conclusions deducible from it to a most unjustifiable extent. They asserted that one and the same nitrogenous substance might undergo various modifications in contact with air, so as to become successively alcoholic, lactic, butyric, and other ferments. There is nothing more convenient than purely hypothetical theories, theories which are not the necessary consequences of facts; when fresh facts which cannot be reconciled with the original hypothesis are discovered, new hypotheses can be tacked on to the old ones. This is exactly what Liebig and Fremy have done, each in his turn, under the pressure of our studies, commenced in 1857. In 1864 Fremy devised the theory of hemi-organism, which meant nothing more than that he gave up Liebig's theory of 1843, together with the additions which Boutron and he had made to it in 1846; in other words, he abandoned the idea of albuminous substances being ferments, to take up another idea, that albuminous substances in contact with air are peculiarly adapted to undergo organization into new beings--that is, the living ferments which we had discovered--and that the ferments of beer and of the grape have a common origin. This theory of hemi-organism was word for word the antiquated opinion of Turpin. * * * The public, especially a certain section of the public did not go very deeply into an examination of the subject. It was the period when the doctrine of spontaneous generation was being discussed with much warmth. The new word hemi-organism, which was the only novelty in M. Fremy's theory, deceived people. It was thought that M. Fremy had really discovered the solution of the question of the day. It is true that it was rather difficult to understand the process by which an albuminous substance could become all at once a living and budding cell. This difficulty was solved by M. Fremy, who declared that it was the result of some power that was not yet understood, the power of "organic impulse." [Footnote: FREMY, Comptes rendus de l'Academie, vol. lviii., p. 1065, 1864.] Liebig, who, as well as M. Fremy, was compelled to renounce his original opinions concerning the nature of ferments, devised the following obscure theory (Memoir by Liebig, 1870, already cited): "There seems to be no doubt as to the part which the vegetable organism plays in the phenomenon of fermentation. It is through it alone that an albuminous substance and sugar are enabled to unite and form this particular combination, this unstable form under which alone, as a component part of the mycoderm, they manifest an action on sugar. Should the mycoderm cease to grow, the bond which unites the constituent parts of the cellular contents is loosened, and it is through the motion produced therein that the cells of yeast bring about a disarrangement or separation of the elements of the sugar into molecules." One might easily believe that the translator for the Annales has made some mistake, so great is the obscurity of this passage. Whether we take this new form of the theory or the old one, neither can be reconciled at all with the development of yeast and fermentation in a saccharine mineral medium, for in the latter experiment fermentation is correlative to the life of the ferment and to its nutrition, a constant change going on between the ferment and its food-matters, since all the carbon assimilated by the ferment is derived from sugar, its nitrogen from ammonia and phosphorus from the phosphates in solution. And even all said, what purpose can be served by the gratuitous hypothesis of contact-action or communicated motion? The experiment of which we are speaking is thus a fundamental one; indeed, it is its possibility that constitutes the most effective point in the controversy. No doubt Liebig might say, "but it is the motion of life and of nutrition which constitutes your experiment, and this is the communicated motion that my theory requires." Curiously enough, Liebig does endeavour, as a matter of fact, to say this, but he does so timidly and incidentally: "From a chemical point of view, which point of view I would not willingly abandon, a VITAL ACTION is a phenomenon of motion, and, in this double sense of LIFE M. Pasteur's theory agrees with my own, and is not in contradiction with it (page 6)." This is true. Elsewhere Liebig says: "It is possible that the only correlation between the physiological act and the phenomenon of fermentation is the production, in the living cell, of the substance which, by some special property analogous to that by which emulsin exerts a decomposing action on salicin and amygdalin, may bring about the decomposition of sugar into other organic molecules; the physiological act, in this view, would be necessary for the production of this substance, but would have nothing else to do with the fermentation (page 10)." To this, again, we have no objection to raise. Liebig, however, does not dwell upon these considerations, which he merely notices in passing, because he is well aware that, as far as the defence of his theory is concerned, they would be mere evasions. If he had insisted on them, or based his opposition solely upon them, our answer would have been simply this: "If you do not admit with us that fermentation is correlated with the life and nutrition of the ferment, we agree upon the principal point. So agreeing, let us examine, if you will, the actual cause of fermentation;--this is a second question, quite distinct from the first. Science is built up of successive solutions given to questions of ever increasing subtlety, approaching nearer and nearer towards the very essence of phenomena. If we proceed to discuss together the question of how living, organized beings act in decomposing fermentable substances, we will be found to fall out once more on your hypothesis of communicated motion, since according to our ideas, the actual cause of fermentation is to be sought, in most cases, in the fact of life without air, which is the characteristic of many ferments." Let us briefly see what Liebig thinks of the experiment in which fermentation is produced by the impregnation of a saccharine mineral medium, a result so greatly at variance with his mode of viewing the question. [Footnote: See our Memoir of 1860 (Annales de Chimie et de Physique, vol. lviii, p. 61, and following, especially pp. 69 and 70, where the details of the experiment will be found).] After deep consideration he pronounces this experiment to be inexact, and the result ill-founded. Liebig, however, was not one to reject a fact without grave reasons for doing so, or with the sole object of evading a troublesome discussion. "I have repeated this experiment," he says, "a great number of times, with the greatest possible care, and have obtained the same results as M. Pasteur, excepting as regards the formation and increase of the ferment." It was, however, the formation and increase of the ferment that constituted the point of the experiment. Our discussion was, therefore, distinctly limited to this: Liebig denied that the ferment was capable of development in a saccharine mineral medium, whilst we asserted that this development did actually take place, and was comparatively easy to prove. In 1871 we replied to M. Liebig before the Paris Academy of Sciences in a Note, in which we offered to prepare in a mineral medium, in the presence of a commission to be chosen for the purpose, as great a weight of ferment as Liebig could reasonably demand. [Footnote: PASTEUR, Comptes rendus de l'Academie des Sciences, vol. lxxiii., p. 1419. 1871.] We were bolder than we should, perhaps, have been in 1860; the reason was that our knowledge of the subject had been strengthened by ten years of renewed research. Liebig did not accept our proposal, nor did he even reply to our Note. Up to the time of his death, which took place on April 18th, 1873, he wrote nothing more on the subject. [Footnote: In his Memoir of 1870, Liebig made a remarkable admission: "My late friend Pelouze," he says, "had communicated to me nine years ago certain results of M. Pasteur's researches on fermentation. I told him that just then I was not disposed to alter my opinion on the cause of fermentation, and that if it were possible, by means of ammonia, to produce or multiply the yeast in fermenting liquors, industry would soon avail itself of the fact, and that I would wait to see if it did so; up to the present time, however, there had not been the least change in the manufacture of yeast. "We do not know what M. Pelouze's reply was; but it is not difficult to conceive so sagacious an observer remarking to his illustrious friend that the possibility of deriving pecuniary advantage from the wide application of a new scientific fact had never been regarded as the criterion of the exactness of that fact. We could prove, moreover, by the undoubted testimony of very distinguished practical men, notably by that of M. Pezeyre, director of distilleries, that upon this point also Liebig was mistaken.] When we published, in 1860, the details of the experiment in question, we pointed out at some length the difficulties of conducting it successfully, and the possible causes of failure. We called attention particularly to the fact that saccharine mineral media are much more suited for the nutrition of bacteria, lactic ferment, and other lowly forms, than they are to that of yeast, and in consequence readily become filled with various organisms from the spontaneous growth of germs derived from the particles of dust floating in the atmosphere. The reason why we do not observe the growth of alcoholic ferments, especially at the commencement of the experiments, is because of the unsuitableness of those media for the life of yeast. The latter may, nevertheless, form in them subsequent to this development of other organized forms, by reason of the modification produced in the original mineral medium by the albuminous matters that they introduce into it. It is interesting to peruse, in our Memoir of 1860, certain facts of the same kind relating to fermentation by means of albumens--that of the blood for example, from which, we may mention incidentally, we were led to infer the existence of several distinct albumens in the serum, a conclusion which, since then, has been confirmed by various observers, notably by M. Bechamp. Now, in his experiments on fermentation in sweetened water, with yeast-ash and a salt of ammonia, there is no doubt that Liebig had failed to avoid those difficulties which are entailed by the spontaneous growth of other organisms than yeast. Moreover, it is possible that, to have established the certainty of this result, Liebig should have had recourse to a closer microscopical observation than from certain passages in his Memoir he seems to have adopted. We have little doubt that his pupils could tell us that Liebig did not even employ that instrument without which any exact study of fermentation is not merely difficult but well-nigh impossible. We ourselves, for the reasons, mentioned, did not obtain a simple alcoholic fermentation any more than Liebig did. In that particular experiment, the details of which we gave in our Memoir of 1860, we obtained lactic and alcoholic fermentation together; an appreciable quantity of lactic acid formed and arrested the propagation of the lactic and alcoholic ferments, so that more than half of the sugar remained in the liquid without fermenting. This, however, in no way detracted from the correctness of the conclusion which we deduced from the experiment, and from other similar ones; it might even be said that, from a general and philosophical point of view--which is the only one of interest here--the result was doubly satisfactory, inasmuch as we demonstrated that mineral media were adapted to the simultaneous development of several organized ferments instead of only one. The fortuitous association of different ferments could not invalidate the conclusion that all the nitrogen of the cells of the alcoholic and lactic ferments was derived from the nitrogen in the ammoniacal salts, and that all the carbon of those ferments was taken from the sugar, since, in the medium employed in our experiment, the sugar was the only substance that contained carbon. Liebig carefully abstained from noticing this fact, which would have been fatal to the very groundwork of his criticisms, and thought that he was keeping up the appearance of a grave contradiction by arguing that we had never obtained a simple alcoholic fermentation. It would be unprofitable to dwell longer upon the subject of the difficulties which the propagation of yeast in a saccharine mineral medium formerly presented. As a matter of fact, the progress of our studies has imparted to the question an aspect very different from that which it formerly wore; it was this circumstance which emboldened us to offer, in our reply to Liebig before the Academy of Sciences in 1871, to prepare, in a saccharine mineral medium, in the presence of a commission to be appointed by our opponent, any quantity of ferment that he might require, and to effect the fermentation of any weight of sugar whatsoever. Our knowledge of the facts detailed in the preceding chapter concerning pure ferments, and their manipulation in the presence of pure air, enables us completely to disregard those causes of embarrassment that result from the fortuitous occurrence of the germs of organisms different in character from the ferments introduced by the air or from the sides of vessels, or even by the ferment itself. Let us once more take one of our double-necked flasks, which we will suppose is capable of containing three or four litres (six to eight pints). Let us put into it the following: Pure distilled water. Sugar candy. ... . ... . ... . ... . ... . 200 grammes Bitartrate of potassium. ... . ... . 1.0 grammes Bitartrate of ammonia. ... . ... ... 0.5 grammes Sulphate of ammonia.,. ... . ... ... 1.5 grammes Ash of yeast. ... . ... . ... . ... . ... 1.5 grammes (1 gramme = 15.43 grains) Let us boil the mixture, to destroy all germs of organisms that may exist in the air or liquid or on the sides of the flask, and then permit it to cool, after having placed, by way of extra precaution a small quantity of asbestos in the end of the fine curved tube. Let us next introduce a trace of ferment into the liquid, through the other neck, which, as we have described, is terminated by a small piece of india-rubber tube closed with a glass stopper. Here are the details of such an experiment:-- On December 9th, 1873, we sowed some pure ferment--saccharomyces pastorianus. From December 11, that is, within so short a time as forty-eight hours after impregnation, we saw a multitude of extremely minute bubbles rising almost continuously from the bottom, indication that at this point the fermentation had commenced. On the following days, several patches of froth appeared on the surface of the liquid. We left the flask undisturbed in the oven, at a temperature of 25 degrees C. (77 degrees F.) On April 24, 1874, we tested some of the liquid, obtained by means of the straight tube, to see if it still contained any sugar. We found that it contained less than two grammes, so that 198 grammes (4.2 oz. Troy) had already disappeared. Some time afterwards the fermentation came to an end; we carried on the experiment, nevertheless, until April 18, 1875. There was no development of any organism absolutely foreign to the ferment, which was itself abundant, a circumstance that, added to the persistent vitality of the ferment, in spite of the unsuitableness of the medium for its nutrition, permitted the perfect completion of fermentation. There was not the minutest quantity of sugar remaining. The total weight of ferment, after washing and drying at 100 degrees C. (212 degrees F.), was 2.563 grammes (39.5 grains). In experiments of this kind, in which the ferment has to be weighed, it is better not to use any yeast-ash that cannot be dissolved completely, so as to be capable of easy separation from the ferment formed. Raulin's liquid [Footnote: M. Jules Raulin has published a well-known and remarkable work on the discovery of the mineral medium best adapted by its composition to the life of certain fungoid growth; he has given a formula for the composition of such a medium. It is this that we call here "Raulin's liquid" for abbreviation. Water . . . . . . . . . . . . . . . . . . 1,500 Sugar candy . . . . . . . . . . . . . . . 70 Tartaric acid . . . . . . . . . . . . . . 4 Nitrate of ammonia . . . . . . . . . . . 4 Phosphate of ammonia . . . . . . . . . . 0.6 Carbonate of potassium . . . . . . . . . 0.6 Carbonate of magnesia . . . . . . . . . . 0.4 Sulphate of ammonia . . . . . . . . . . . 0.25 Sulphate of zinc . . . . . . . . . . . . 0.07 Sulphate of iron . . . . . . . . . . . . 0.07 Silicate of potassium . . . . . . . . . . 0.07 --J. Raulin, Paris, Victor Masson, 1870. These pour le doctorat.] may be used in such cases with success. All the alcoholic ferments are not capable to the same extent of development by means of phosphates, ammoniacal salts, and sugar. There are some whose development is arrested a longer or shorter time before the transformation of all the sugar. In a series of comparative experiments, 200 grammes of sugar-candy being used in each case, we found that whilst saccharomyces pastorianus effected a complete fermentation of the sugar, the caseous ferment did not decompose more than two-thirds, and the ferment we have designated NEW "HIGH" FERMENT not more than one-fifth: and keeping the flasks for a longer time in the oven had no effect in increasing the proportions of sugar fermented in these two last cases. We conducted a great number of fermentations in mineral media, in consequence of a circumstance which it may be interesting to mention here. A person who was working in our laboratory asserted that the success of our experiments depended upon the impurity of the sugar-candy which we employed, and that if this sugar had been pure--much purer than was the ordinary, white, commercial sugar-candy, which up to that time we had always used--the ferment could not have multiplied. The persistent objections of our friend, and our desire to convince him, caused us to repeat all our previous experiments on the subject, using sugar of great purity, which had been specially prepared for us, with the utmost care, by a skilful confectioner, Seugnot. The result only confirmed our former conclusions. Even this did not satisfy our obstinate friend, who went to the trouble of preparing some pure sugar for himself, in little crystals, by repeated crystallizations of carefully selected commercial sugar-candy; he then repeated our experiments himself. This time his doubts were overcome. It even happened that the fermentations with the perfectly pure sugar instead of being slow were very active, when compared with those which we had conducted with, the commercial sugar-candy. We may here add a few words on the non-transformation of yeast into penicillium glaucum. If at any time during fermentation we pour off the fermenting liquid, the deposit of yeast remaining in the vessel may continue there, in contact with air, without our ever being able to discover the least formation of penicillium glaucum in it. We may keep a current of pure air constantly passing through the flask; the experiment will give the same result. Nevertheless, this is a medium peculiarly adapted to the development of this mould, inasmuch as if we were to introduce merely a few spores of penicillium an abundant vegetation of that growth will afterwards appear on the deposit. The descriptions of Messrs. Turpin, Hoffmann, and Trecul have, therefore, been based on one of these illusions which we meet with so frequently in microscopical observations. When we laid these facts before the Academy, [Footnote: PASTEUR, Comptes rendus de l'Academie, vol. lxxviii., pp. 213-216.] M. Trecul professed his inability to comprehend them: [Footnote: TRECUL, Comptes rendus de l'Academie, vol. lxxviii., pp. 217, 218.] "According to M. Pasteur," he said, "the yeast of beer is ANAEROBIAN, that is to say, it lives in a liquid deprived of free oxygen; and to become mycoderma or penicillium it is above all things necessary that it should be placed in air, since, without this, as the name signifies, an aerobian being cannot exist. To bring about the transformation of the yeast of beer into mycoderma cerevisiae or into penicillium glaucum we must accept the conditions under which these two forms are obtained. If M. Pasteur will persist in keeping his yeast in media which are incompatible with the desired modification, it is clear that the results which he obtains must always be negative." Contrary to this perfectly gratuitous assertion of M. Trecul's we do not keep our yeast in media which are calculated to prevent its transformation into penicillium. As we have just seen, the principal aim and object of our experiment was to bring this minute plant into contact with air, and under conditions that would allow the penicillium to develop with perfect freedom. We conducted our experiments exactly as Turpin and Hoffmann conducted theirs, and exactly as they stipulate that such experiments should be conducted--with the one sole difference, indispensable to the correctness of our observations, that we carefully guarded ourselves against those causes of error which they did not take the least trouble to avoid. It is possible to produce a ready entrance and escape of pure air in the case of the double-necked flasks which we have so often employed in the course of this work, without having recourse to the continuous passage of a current of air. Having made a file-mark on the thin curved neck at a distance of two or three centimetres (an inch) from the flask, we must cut round the neck at this point with a glazier's diamond, and then remove it, taking care to cover the opening immediately with a sheef of paper which has been passed through the flame, and which we must fasten with a thread round the part of the neck still left. In this manner we may increase or prolong the fructification of fungoid growths, or the life of the aerobian ferments in our flasks. What we have said of Penicillium glaucum will apply equally to Mycoderma cerevisiae. Notwithstanding that Turpin and Trecul may assert to the contrary, yeast, in contact with air as it was under the conditions of the experiment just described, will not yield Mycoderma vini or Mycoderma cerevisiae any more than it will Penicillium. The experiments described in the preceding paragraphs on the increase of organized ferments in mineral media of the composition described, are of the greatest physiological interest. Amongst other results, they show that all the proteic matter of ferments may be produced by the vital activity of the cells, which, apart altogether from the influence of light or free oxygen (unless indeed, we are dealing with aerobian moulds which require free oxygen), have the power of developing a chemical activity between carbohydrates, ammoniacal salts, phosphates, and sulphates of potassium and magnesium. It may be admitted with truth that a similar effect obtains in the case of the higher plants, so that in the existing state of science we fail to conceive what serious reason can be urged against our considering this effect as general. It would be perfectly logical to extend the results of which we are speaking to all plants, and to believe that the proteic matter of vegetables, and perhaps of animals also, is formed exclusively by the activity of the cells operating upon the ammoniacal and other mineral salts of the sap or plasma of the blood, and the carbo-hydrates, the formation of which, in the case of the higher plants, requires only the concurrence of the chemical impulse of green light. Viewed in this manner, the formation of the proteic substances, would be independent of the great act of reduction of carbonic acid gas under the influence of light. These substances would not be built up from the elements of water, ammonia, and carbonic acid gas, after the decomposition of this last; they would be formed where they are found in the cells themselves, by some process of union between the carbo-hydrates imported by the sap, and the phosphates of potassium and magnesium and salts of ammonia. Lastly, in vegetable growth, by means of a carbo-hydrate and a mineral medium, since the carbo-hydrate is capable of many variations, and it would be difficult to understand how it could be split up into its elements before serving to constitute the proteic substances, and even cellulose substances, as these are carbo-hydrates. We have commenced certain studies in this direction. If solar radiation is indispensable to the decomposition of carbonic acid and the building up of the primary substances in the case of higher vegetable life, it is still possible that certain inferior organisms may do without it and nevertheless yield the most complex substances, fatty or carbo-hydrate, such as cellulose, various organic acids, and proteic matter; not, however, by borrowing their carbon from the carbonic acid which is saturated with oxygen, but from other matters still capable of acquiring oxygen, and so of yielding heat in the process, such as alcohol and acetic acid, for example, to cite merely carbon compounds most removed from organization. As these last compounds, and a host of others equally adapted to serve as the carbonaceous food of mycoderms and the mucedines, may be produced synthetically by means of carbon and the vapour of water, after the methods that science owes to Berthelot, it follows that, in the case of certain inferior beings, life would be possible even if it should be that the solar light was extinguished. [Footnote: See on this subject the verbal observations which we addressed to the Academy of Sciences at its meetings of April 10th and 24th, 1876]. THE GERM THEORY AND ITS APPLICATIONS TO MEDICINE AND SURGERY [Footnote: Read before the French Academy of Sciences, April 29th, 1878. Published in Comptes Rendus de l' Academie des Sciences, lxxxvi., pp. 1037-43.] The Sciences gain by mutual support. When, as the result of my first communications on the fermentations in 1857-1858, it appeared that the ferments, properly so-called, are living beings, that the germs of microscopic organisms abound in the surface of all objects, in the air and in water; that the theory of spontaneous generation is chimerical; that wines, beer, vinegar, the blood, urine and all the fluids of the body undergo none of their usual changes in pure air, both Medicine and Surgery received fresh stimulation. A French physician, Dr. Davaine, was fortunate in making the first application of these principles to Medicine, in 1863. Our researches of last year, left the etiology of the putrid disease, or septicemia, in a much less advanced condition than that of anthrax. We had demonstrated the probability that septicemia depends upon the presence and growth of a microscopic body, but the absolute proof of this important conclusion was not reached. To demonstrate experimentally that a microscopic organism actually is the cause of a disease and the agent of contagion, I know no other way, in the present state of Science, than to subject the microbe (the new and happy term introduced by M. Sedillot) to the method of cultivation out of the body. It may be noted that in twelve successive cultures, each one of only ten cubic centimeters volume, the original drop will be diluted as if placed in a volume of fluid equal to the total volume of the earth. It is just this form of test to which M. Joubert and I subjected the anthrax bacteridium. [Footnote: In making the translation, it seems wiser to adhere to Pasteur's nomenclature. Bacillus anthracis would be the term employed to-day.-- Translator.] Having cultivated it a great number of times in a sterile fluid, each culture being started with a minute drop from the preceding, we then demonstrated that the product of the last culture was capable of further development and of acting in the animal tissues by producing anthrax with all its symptoms. Such is--as we believe--the indisputable proof that ANTHRAX IS A BACTERIAL DISEASE. Our researches concerning the septic vibrio had not so far been convincing, and it was to fill up this gap that we resumed our experiments. To this end, we attempted the cultivation of the septic vibrio from an animal dead of septicemia. It is worth noting that all of our first experiments failed, despite the variety of culture media we employed--urine, beer yeast water, meat water, etc. Our culture media were not sterile, but we found--most commonly--a microscopic organism showing no relationship to the septic vibrio, and presenting the form, common enough elsewhere, of chains of extremely minute spherical granules possessed of no virulence whatever. [Footnote: It is quite possible that Pasteur was here dealing with certain septicemic streptococci that are now know to lose their virulence with extreme rapidity under artificial cultivation.--Translator.] This was an impurity, introduced, unknown to us, at the same time as the septic vibrio; and the germ undoubtedly passed from the intestines--always inflamed and distended in septicemic animals-- into the abdominal fluids from which we took our original cultures of the septic vibrio. If this explanation of the contamination of our cultures was correct, we ought to find a pure culture of the septic vibrio in the heart's blood of an animal recently dead of septicemia. This was what happened, but a new difficulty presented itself; all our cultures remained sterile. Furthermore this sterility was accompanied by loss in the culture media of (the original) virulence. It occurred to us that the septic vibrio might be an obligatory anaerobe and that the sterility of our inoculated culture fluids might be due to the destruction of the septic vibrio by the atmospheric oxygen dissolved in the fluids. The Academy may remember that I have previously demonstrated facts of this nature in regard to the vibrio of butyric fermentation, which not only lives without air but is killed by the air. It was necessary therefore to attempt to cultivate the septic vibrio either in a vacuum or in the presence of inert gases--such as carbonic acid. Results justified our attempt; the septic vibrio grew easily in a complete vacuum, and no less easily in the presence of pure carbonic acid. These results have a necessary corollary. If a fluid containing septic vibrios be exposed to pure air, the vibrios should be killed and all virulence should disappear. This is actually the case. If some drops of septic serum be spread horizontally in a tube and in a very thin layer, the fluid will become absolutely harmless in less than half a day, even if at first it was so virulent as to produce death upon the inoculation of the smallest portion of a drop. Furthermore all the vibrios, which crowded the liquid as motile threads, are destroyed and disappear. After the action of the air, only fine amorphous granules can be found, unfit for culture as well as for the transmission of any disease whatever. It might be said that the air burned the vibrios. If it is a terrifying thought that life is at the mercy of the multiplication of these minute bodies, it is a consoling hope that Science will not always remain powerless before such enemies, since for example at the very beginning of the study we find that simple exposure to air is sufficient at times to destroy them. But, if oxygen destroys the vibrios, how can septicemia exist, since atmospheric air is present everywhere? How can such facts be brought in accord with the germ theory? How can blood, exposed to air, become septic through the dust the air contains? All things are hidden, obscure and debatable if the cause of the phenomena be unknown, but everything is clear if this cause be known. What we have just said is true only of a septic fluid containing adult vibrios, in active development by fission: conditions are different when the vibrios are transformed into their germs, [Footnote: By the terms "germ" and "germ corpuscles," Pasteur undoubtedly means "spores," but the change is not made, in accordance with note 3, above.--Translator.] that is into the glistening corpuscles first described and figured in my studies on silk-worm disease, in dealing with worms dead of the disease called "flacherie." Only the adult vibrios disappear, burn up, and lose their virulence in contact with air: the germ corpuscles, under these conditions, remain always ready for new cultures, and for new inoculations. All this however does not do away with the difficulty of understanding how septic germs can exist on the surface of objects, floating in the air and in water. Where can these corpuscles originate? Nothing is easier than the production of these germs, in spite of the presence of air in contact with septic fluids. If abdominal serous exudate containing septic vibrios actively growing by fission be exposed to the air, as we suggested above, but with the precaution of giving a substantial thickness to the layer, even if only one centimeter be used, this curious phenomenon will appear in a few hours. The oxygen is absorbed in the upper layers of the fluid--as is indicated by the change of color. Here the vibrios are dead and disappear. In the deeper layers, on the other hand, towards the bottom of this centimeter of septic fluid we suppose to be under observation, the vibrios continue to multiply by fission--protected from the action of oxygen by those that have perished above them: little by little they pass over to the condition of germ corpuscles with the gradual disappearance of the thread forms. So that instead of moving threads of varying length, sometimes greater than the field of the microscope, there is to be seen only a number of glittering points, lying free or surrounded by a scarcely perceptible amorphous mass. [Footnote: In our note of July 16th, 1877, it is stated that the septic vibrio is not destroyed by the oxygen of the air nor by oxygen at high tension, but that under these conditions it is transformed into germ-corpuscles. This is, however, an incorrect interpretation of facts. The vibrio is destroyed by oxygen, and it is only where it is in a thick layer that it is transformed to germ-corpuscles in the presence of oxygen and that its virulence is preserved.] Thus is formed, containing the latent germ life, no longer in danger from the destructive action of oxygen, thus, I repeat, is formed the septic dust, and we are able to understand what has before seemed so obscure; we can see how putrescible fluids can be inoculated by the dust of the air, and how it is that putrid diseases are permanent in the world. The Academy will permit me, before leaving these interesting results, to refer to one of their main theoretical consequences. At the very beginning of these researches, for they reveal an entirely new field, what must be insistently demanded? The absolute proof that there actually exist transmissible, contagious, infectious diseases of which the cause lies essentially and solely in the presence of microscopic organisms. The proof that for at least some diseases, the conception of spontaneous virulence must be forever abandoned--as well as the idea of contagion and an infectious element suddenly originating in the bodies of men or animals and able to originate diseases which propagate themselves under identical forms: and all of those opinions fatal to medical progress, which have given rise to the gratuitous hypotheses of spontaneous generation, of albuminoid ferments, of hemiorganisms, of archebiosis, and many other conceptions without the least basis in observation. What is to be sought for in this instance is the proof that along with our vibrio there does not exist an independent virulence belonging to the surrounding fluids or solids, in short that the vibrio is not merely an epiphenomenon of the disease of which it is the obligatory accompaniment. What then do we see, in the results that I have just brought out? A septic fluid, taken at the moment that the vibrios are not yet changed into germs, loses its virulence completely upon simple exposure to the air, but preserves this virulence, although exposed to air on the simple condition of being in a thick layer for some hours. In the first case, the virulence once lost by exposure to air, the liquid is incapable of taking it on again upon cultivation: but, in the second case, it preserves its virulence and can propagate, even after exposure to air. It is impossible, then, to assert that there is a separate virulent substance, either fluid or solid, existing, apart from the adult vibrio or its germ. Nor can it be supposed that there is a virus which loses its virulence at the moment that the adult vibrio dies; for such a substance should also lose its virulence when the vibrios, changed to germs, are exposed to the air. Since the virulence persists under these conditions it can only be due to the germ corpuscles--the only thing present. There is only one possible hypothesis as to the existence of a virus in solution, and that is that such a substance, which was present in our experiment in nonfatal amounts, should be continuously furnished by the vibrio itself, during its growth in the body of the living animal. But it is of little importance since the hypothesis supposes the forming and necessary existence of the vibrio. [Footnote: The regular limits, oblige me to omit a portion of my speech.] I hasten to touch upon another series of observations which are even more deserving the attention of the surgeon than the preceding: I desire to speak of the effects of our microbe of pus when associated with the septic vibrio. There is nothing more easy to superpose--as it were--two distinct diseases and to produce what might be called a SEPTICEMIC PURULENT INFECTION, or a PURULENT SEPTICEMIA. Whilst the microbe-producing pus, when acting alone, gives rise to a thick pus, white, or sometimes with a yellow or bluish tint, not putrid, diffused or enclosed by the so-called pyogenic membrane, not dangerous, especially if localized in cellular tissue, ready, if the expression may be used for rapid resorption; on the other hand the smallest abscess produced by this organism when associated with the septic vibrio takes on a thick gangrenous appearance, putrid, greenish and infiltrating the softened tissues. In this case the microbe of pus carried so to speak by the septic vibrio, accompanies it throughout the body: the highly-inflamed muscular tissues, full of serous fluid, showing also globules of pus here and there, are like a kneading of the two organisms. By a similar procedure the effects of the anthrax bacteridium and the microbe of pus may be combined and the two diseases may be superposed, so as to obtain a purulent anthrax or an anthracoid purulent infection. Care must be taken not to exaggerate the predominance of the new microbe over the bacteridum. If the microbe be associated with the latter in sufficient amount it may crowd it out completely--prevent it from growing in the body at all. Anthrax does not appear, and the infection, entirely local, becomes merely an abscess whose cure is easy. The microbe- producing pus and the septic vibrio (not) [Footnote: There is undoubtedly a mistake in the original. Pasteur could not have meant to say that both bacteria are anaerobes. The word "not" is introduced to correct the error.--Translator.] being both anaerobes, as we have demonstrated, it is evident that the latter will not much disturb its neighbor. Nutrient substances, fluid or solid, can scarcely be deficient in the tissues from such minute organisms. But the anthrax bacteridium is exclusively aerobic, and the proportion of oxygen is far from being equally distributed throughout the tissues: innumerable conditions can diminish or exhaust the supply here and there, and since the microbe-producing pus is also aerobic, it can be understood how, by using a quantity slightly greater than that of the bacteridium it might easily deprive the latter of the oxygen necessary for it. But the explanation of the fact is of little importance: it is certain that under some conditions the microbe we are speaking of entirely prevents the development of the bacteridium. Summarizing--it appears from the preceding facts that it is possible to produce at will, purulent infections with no elements of putrescence, putrescent purulent infections, anthracoid purulent infections, and finally combinations of these types of lesions varying according to the proportions of the mixtures of the specific organisms made to act on the living tissues. These are the principal facts I have to communicate to the Academy in my name and in the names of my collaborators, Messrs. Joubert and Chamberland. Some weeks ago (Session of the 11th of March last) a member of the Section of Medicine and Surgery, M. Sedillot, after long meditation on the lessons of a brilliant career, did not hesitate to assert that the successes as well as the failures of Surgery find a rational explanation in the principles upon which the germ theory is based, and that this theory would found a new Surgery--already begun by a celebrated English surgeon, Dr. Lister, [Footnote: See Lord Lister's paper in the present volume.--Ed.] who was among the first to understand its fertility. With no professional authority, but with the conviction of a trained experimenter, I venture here to repeat the words of an eminent confrere. ON THE EXTENSION OF THE GERM THEORY TO THE ETIOLOGY OF CERTAIN COMMON DISEASES [Footnote: Read before the French Academy of Sciences, May 3, 1880. Published in Comptes rendus, de l'Academie des Sciences, xc., pp. 1033-44.] When I began the studies now occupying my attention, [Footnote: In 1880. Especially engaged in the study of chicken cholera and the attenuation of virulence--Translator.] I was attempting to extend the germ theory to certain common diseases. I do not know when I can return to that work. Therefore in my desire to see it carried on by others, I take the liberty of presenting it to the public in its present condition. I. Furuncles. In May, 1879, one of the workers in my laboratory had a number of furuncles, appearing at short intervals, sometimes on one part of the body and sometimes on another. Constantly impressed with the thought of the immense part played by microscopic organisms in Nature, I queried whether the pus in the furuncles might not contain one of these organisms whose presence, development, and chance transportation here and there in the tissues after entrance would produce a local inflammation, and pus formation, and might explain the recurrence of the illness during a longer or shorter time. It was easy enough to subject this thought to the test of experiment. First observation.--On June second, a puncture was made at the base of the small cone of pus at the apex of a furuncle on the nape of the neck. The fluid obtained was at once sowed in the presence of pure air--of course with the precautions necessary to exclude any foreign germs, either at the moment of puncture, at the moment of sowing in the culture fluid, or during the stay in the oven, which was kept at the constant temperature of about 35 degrees C, The next day, the culture fluid had become cloudy and contained a single organism, consisting of small spherical points arranged in pairs, sometimes in fours, but often in irregular masses. Two fluids were preferred in these experiments--chicken and yeast bouillon. According as one or the other was used, appearances varied a little. These should be described. With the yeast water, the pairs of minute granules are distributed throughout the liquid, which is uniformly clouded. But with the chicken bouillon, the granules are collected in little masses which line the walls and bottom of the flasks while the body of the fluid remains clear, unless it be shaken: in this case it becomes uniformly clouded by the breaking up of the small masses from the walls of the flasks. Second observation.--On the tenth of June a new furuncle made its appearance on the right thigh of the same person. Pus could not yet be seen under the skin, but this was already thickened and red over a surface the size of a franc. The inflamed part was washed with alcohol, and dried with blotting paper passed through the flame of an alcohol lamp. A puncture at the thickened portion enabled us to secure a small amount of lymph mixed with blood, which was sowed at the same time as some blood taken from the finger of the hand. The following days, the blood from the finger remained absolutely sterile: but that obtained from the center of the forming furuncle gave an abundant growth of the same small organism as before. Third observation.--The fourteenth of June, a new furuncle appeared on the neck of the same person. The same examination, the same result, that is to say the development of the microscopic organism previously described and complete sterility of the blood of the general circulation, taken this time at the base of the furuncle outside of the inflamed area. At the time of making these observations I spoke of them to Dr. Maurice Reynaud, who was good enough to send me a patient who had had furuncles for more than three months. On June thirteenth I made cultures of the pus from a furuncle of this man. The next day there was a general cloudiness of the culture fluids, consisting entirely of the preceding parasite, and of this alone. Fourth observation.--June fourteenth, the same individual showed me a newly forming furuncle in the left axilla: there was wide- spread thickening and redness of the skin, but no pus was yet apparent. An incision at the center of the thickening showed a small quantity of pus mixed with blood. Sowing, rapid growth for twenty-four hours and the appearance of the same organism. Blood from the arm at a distance from the furuncle remained completely sterile. June 17, the examination of a fresh furuncle on the same individual gave the same result, the development of a pure culture of the same organism. Fifth observation.--July twenty-first, Dr. Maurice Reynaud informed me that there was a woman at the Lariboisiere hospital with multiple furuncles. As a matter of fact her back was covered with them, some in active suppuration, others in the ulcerating stage. I took pus from all of these furuncles that had not opened. After a few hours, this pus gave an abundant growth in cultures. The same organism, without admixture, was found. Blood from the inflamed base of the furuncle remained sterile. In brief, it appears certain that every furuncle contains an aerobic microscopic parasite, to which is due the local inflammation and the pus formation that follows. Culture fluids containing the minute organism inoculated under the skin of rabbits and guinea-pigs produce abscesses generally small in size and that promptly heal. As long as healing is not complete the pus of the abscesses contains the microscopic organism which produced them. It is therefore living and developing, but its propagation at a distance does not occur. These cultures of which I speak, when injected in small quantities in the jugular vein of guinea pigs show that the minute organism does not grow in the blood. The day after the injection they cannot be recovered even in cultures. I seem to have observed as a general principle, that, provided the blood corpuscles are in good physiological condition it is difficult for aerobic parasites to develop in the blood. I have always thought that this is to be explained by a kind of struggle between the affinity of the blood corpuscles for oxygen and that belonging to the parasite in cultures. Whilst the blood corpuscles carry off, that is, take possession of all the oxygen, the life and development of the parasite become extremely difficult or impossible. It is therefore easily eliminated, digested, if one may use the phrase. I have seen these facts many times in anthrax and chicken-cholera, diseases both of which are due to the presence of an aerobic parasite. Blood cultures from the general circulation being always sterile in these experiments, it would seem that under the conditions of the furuncular diathesis, the minute parasite does not exist in the blood. That it cannot be cultivated for the reason given, and that it is not abundant is evident; but, from the sterility of the cultures reported (five only) it should not be definitely concluded that the little parasite may not, at some time, be taken up by the blood and transplanted from a furuncle when it is developing to another part of the body, where it may be accidentally lodged, may develop and produce a new furuncle. I am convinced that if, in cases of furuncular diathesis, not merely a few drops but several grams of blood from the general circulation could be placed under cultivation frequent successful growths would be obtained. [Footnote: This prediction is fully carried out in the present day successful use of considerable amounts of blood in cultures and the resultant frequent demonstrations of bacteria present in the circulation in many infections.-- Translator.] In the many experiments I have made on the blood in chicken-cholera, I have frequently demonstrated that repeated cultures from droplets of blood do not show an even development even where taken from the same organ, the heart for example, and at the moment when the parasite begins its existence in the blood, which can easily be understood. Once even, it happened that only three out of ten chickens died after inoculation with infectious blood in which the parasite had just began to appear, the remaining seven showed no symptoms whatever. In fact, the microbe, at the moment of beginning its entrance into the blood may exist singly or in minute numbers in one droplet and not at all in its immediate neighbor. I believe therefore that it would be extremely instructive in furunculosis, to find a patient willing to submit to a number of punctures in different parts of the body away from formed or forming furuncles, and thus secure many cultures, simultaneous of otherwise, of the blood of the general circulation. I am convinced that among them would be found growths of the micro-organism of furuncles. II. On Osteomyelitis. Single observation. I have but one observation relating to this severe disease, and in this Dr. Lannelongue took the initiative. The monograph on osteomyelitis published by this learned practitioner is well known, with his suggestion of the possibility of a cure by trephining the bone and the use of antiseptic washes and dressings. On the fourteenth of February, at the request of Dr. Lannelongue I went to the Sainte-Eugenie hospital, where this skillful surgeon was to operate on a little girl of about twelve years of age. The right knee was much swollen, as well as the whole leg below the calf and a part of the thigh above the knee. There was no external opening. Under chloroform, Dr. Lannelongue made a long incision below the knee which let out a large amount of pus; the tibia was found denuded for a long distance. Three places in the bone were trephined. From each of these, quantities of pus flowed. Pus from inside and outside the bone was collected with all possible precautions and was carefully examined and cultivated later. The direct microscopic study of the pus, both internal and external, was of extreme interest. It was seen that both contained large numbers of the organism similar to that of furuncles, arranged in pairs, in fours and in packets, some with sharp clear contour, others only faintly visible and with very pale outlines. The external pus contained many pus corpuscles, the internal had none at all. It was like a fatty paste of the furuncular organism. Also, it may be noted, that growth of the small organism had begun in less than six hours after the cultures were started. Thus I saw, that it corresponded exactly with the organism of furuncles. The diameter of the individuals was found to be one one-thousandth of a millimeter. If I ventured to express myself so I might say that in this case at least the osteomyelitis was really a furuncle of the bone marrow. [Footnote: This has been demonstrated, as is well known.--Translator.] It is undoubtedly easy to induce osteomyelitis artificially in living animals. III. On puerperal fever.--First observation. On the twelfth of March, 1878, Dr. Hervieux was good enough to admit me to his service in the Maternity to visit a woman delivered some days before and seriously ill with puerperal fever. The lochia were extremely fetid. I found them full of micro-organisms of many kinds. A small amount of blood was obtained from a puncture on the index finger of the left hand, (the finger being first properly washed and dried with a STERILE towel,) and then sowed in chicken bouillon. The culture remained sterile during the following days. The thirteenth, more blood was taken from a puncture in the finger and this time growth occurred. As death took place on the sixteenth of March at six in the morning, it seems that the blood contained a microscopic parasite at least three days before. The fifteenth of March, eighteen hours before death, blood from a needle-prick in the left foot was used. This culture also was fertile. The first culture, of March thirteenth, contained only the organism of furuncles; the next one, that of the fifteenth, contained an organism resembling that of furunculosis, but which always differed enough to make it easy usually to distinguish it. In this way; whilst the parasite of furuncles is arranged in pairs, very rarely in chains of three or four elements, the new one, that of the culture of the fifteenth, occurs in long chains, the number of cells in each being indefinite. The chains are flexible and often appear as little tangled packets like tangled strings of pearls. The autopsy was performed on the seventeenth at two o'clock. There was a large amount of pus in the peritoneum. It was sowed with all possible precautions. Blood from the basilic and femoral veins was also sowed. So also was pus from the mucous surface of the uterus, from the tubes, and finally that from a lymphatic in the uterine wall. These are the results of these cultures: in all there were the long chains of cells just spoken of above, and nowhere any mixture of other organisms, except in the culture from the peritoneal pus, which, in addition to the long chains, also contained the small pyogenic vibrio which I describe under the name ORGANISM OF PUS in the Note I published with Messrs. Joubert and Chamberland on the thirtieth of April, 1878. [Footnote: See preceding paper.] Interpretation of the disease and of the death.--After confinement, the pus that always naturally forms in the injured parts of the uterus instead of remaining pure becomes contaminated with microscopic organisms from outside, notably the organism in long chains and the pyogenic vibrio. These organisms pass into the peritoneal cavity through the tubes or by other channels, and some of them into the blood, probably by the lymphatics. The resorption of the pus, always extremely easy and prompt when it is pure, becomes impossible through the presence of the parasites, whose entrance must be prevented by all possible means from the moment of confinement. Second observation.--The fourteenth of March, a woman died of puerperal fever at the Lariboisiere hospital; the abdomen was distended before death. Pus was found in abundance by a peritoneal puncture and was sowed; so also was blood from a vein in the arm. The culture of pus yielded the long chains noted in the preceding observation and also the small pyogenic vibrio. The culture from the blood contained only the long chains. Third observation.--The seventeenth of May, 1879, a woman, three days past confinement, was ill, as well as the child she was nursing. The lochia were full of the pyogenic vibrio and of the organism of furuncles, although there was but a small proportion of the latter. The milk and the lochia were sowed. The milk gave the organism in long chains of granules, and the lochia only the pus organism. The mother died, and there was no autopsy. On May twenty-eighth, a rabbit was inoculated under the skin of the abdomen with five drops of the preceding culture of the pyogenic vibrio. The days following an enormous abscess formed which opened spontaneously on the fourth of June. An abundantly cheesy pus came from it. About the abscess there was extensive induration. On the eighth of June, the opening of the abscess was larger, the suppuration active. Near its border was another abscess, evidently joined with the first, for upon pressing it with the finger, pus flowed freely from the opening in the first abscess. During the whole of the month of June, the rabbit was sick and the abscesses suppurated, but less and less. In July they closed; the animal was well. There could only be felt some nodules under the skin of the abdomen. What disturbances might not such an organism carry into the body of a parturient woman, after passing into the peritoneum, the lymphatics or the blood through the maternal placenta! Its presence is much more dangerous than that of the parasite arranged in chains. Furthermore, its development is always threatening, because, as said in the work already quoted (April, 1878) this organism can be easily recovered from many ordinary waters. I may add that the organism in long chains, and that arranged in pairs are also extremely widespread, and that one of their habitats is the mucous surfaces of the genital tract. [Footnote: When, by the procedure I elsewhere described, urine is removed in a pure condition by the urethra from the bladder, if any chance growth occurs through some error of technic, it is the two organisms of which I have been speaking that are almost exclusively present.] Apparently there is no puerperal parasite, properly speaking. I have not encountered true septicemia in my experiments; but it ought to be among the puerperal affections. Fourth observation.--On June fourteenth, at the Lariboisiere, a woman was very ill following a recent confinement; she was at the point of death; in fact she did die on the fourteenth at midnight. Some hours before death pus was taken from an abscess on the arm, and blood from a puncture in a finger. Both were sowed. On the next day (the fifteenth) the flask containing the pus from the abscess was filled with long chains of granules. The flask containing the blood was sterile. The autopsy was at ten o'clock on the morning of the sixteenth. Blood from a vein of the arm, pus from the uterine walls and that from a collection in the synovial sac of the knee were all placed in culture media. All showed growth, even the blood, and they all contained the long strings of granules. The peritoneum contained no pus. Interpretation of the disease and of the death.--The injury of the uterus during confinement as usual furnished pus, which gave a lodging place for the germs of the long chains of granules. These, probably through the lymphatics, passed to the joints and to some other places, thus being the origin of the metastic abscesses which produced death. Fifth observation.--On June seventeenth, M. Doleris, a well-known hospital interne, brought to me some blood, removed with the necessary precautions, from a child dead immediately after birth, whose mother, before confinement had had febrile symptoms with chills. This blood, upon cultivation, gave an abundance of the pyogenic vibrio. On the other hand, blood taken from the mother on the morning of the eighteenth (she had died at one o'clock that morning) showed no development whatever, on the nineteenth nor on following days. The autopsy on the mother took place on the nineteenth. It is certainly worthy of note that the uterus, peritoneum and intestines showed nothing special, but the liver was full of metastatic abscesses. At the exit of the hepatic vein from the liver there was pus, and its walls were ulcerated at this place. The pus from the liver abscesses was filled with the pyogenic vibrio. Even the liver tissues, at a distance from the visible abscesses, gave abundant cultures of the same organism. Interpretation of the disease and of the death.--The pyogenic vibrio, found in the uterus, or which was perhaps already in the body of the mother, since she suffered from chills before confinement, produced metastatic abscesses in the liver and, carried to the blood of the child, there induced one of the forms of infection called purulent, which caused its death. Sixth observation.--The eighteenth of June, 1879, M. Doleris informed me that a woman confined some days before at the Cochin Hospital, was very ill. On the twentieth of June, blood from a needle-prick in the finger was sowed; the culture was sterile. On July fifteenth, that is to say twenty-five days later, the blood was tried again. Still no growth. There was no organism distinctly recognizable in the lochia: the woman was nevertheless, they told me, dangerously ill and at the point of death. As a matter of fact, she did die on the eighteenth of July at nine in the morning: as may be seen, after a very long illness, for the first observations were made over a month before: the illness was also very painful, for the patient could make no movement without intense suffering. An autopsy was made on the nineteenth at ten in the morning, and was of great interest. There was purulent pleurisy with a considerable pocket of pus, and purulent false membranes on the walls of the pleura. The liver was bleached, fatty, but of firm consistency, and with no apparent metastatic abscesses. The uterus, of small size, appeared healthy; but on the external surface whitish nodules filled with pus were found. THERE WAS NOTHING IN THE PERITONEUM, WHICH WAS NOT INFLAMED; but there was much pus in the shoulder joints and the symphysis pubis. The pus from the abscesses, upon cultivation, gave the long chains of granules--not only that of the pleura, but that from the shoulders and a lymphatic of the uterus as well. An interesting thing, but easily understood, was that the blood from a vein in the arm and taken three-quarters of an hour after death was entirely sterile. Nothing grew from the Fallopian tubes nor the broad ligaments. Interpretation of the disease and of the death.--The pus found in the uterus after confinement became infected with germs of microscopic organisms which grew there, then passed into the uterine lymphatics, and from there went on to produce pus in the pleura and in the articulations. Seventh observation.--On June eighteenth, M. Doleris informed me that a woman had been confined at the Cochin Hospital five days before and that fears were entertained as to the results of an operation that had been performed, it having been necessary to do an embryotomy. The lochia were sowed on the 18th; there was not the slightest trace of growth the next day nor the day after. Without the least knowledge of this woman since the eighteenth, on the twentieth I ventured to assert that she would get well. I sent to inquire about her. This is the text of the report: "THE WOMAN IS DOING EXTREMELY WELL; SHE GOES OUT TOMORROW" Interpretation of the facts.--The pus naturally formed on the surface of the injured parts did not become contaminated with organisms brought from without. Natura medicatrix carried it off, that is to say the vitality of the mucous surfaces prevented the development of foreign germs. The pus was easily resorbed, and recovery took place. I beg the Academy to permit me, in closing, to submit certain definite views, which I am strongly inclined to consider as legitimate conclusions from the facts I have had the honor to communicate to it. Under the expression PUERPERAL FEVER are grouped very different diseases, [Footnote: Interesting as the starting point of the conception of diseases according to the etiological factor, not by groups of symptoms.--Translator.] but all appearing to be the result of the growth of common organisms which by their presence infect the pus naturally formed on injured surfaces, which spread by one means or another, by the blood or the lymphatics, to one or another part of the body, and there induce morbid changes varying with the condition of the parts, the nature of the parasite, and the general constitution of the subject. Whatever this constitution, does it not seem that by taking measures opposing the production of these common parasitic organisms recovery would usually occur, except perhaps when the body contains, before confinement, microscopic organisms, in contaminated internal or external abscesses, as was seen in one striking example (fifth observation). The antiseptic method I believe likely to be sovereign in the vast majority of cases. It seems to me that IMMEDIATELY AFTER CONFINEMENT the application of antiseptics should be begun. Carbolic acid can render great service, but there is another antiseptic, the use of which I am strongly inclined to advise, this is boric acid in concentrated solution, that is, four per cent. at the ordinary temperature. This acid, whose singular influence on cell life has been shown by M. Dumas, is so slightly acid that it is alkaline to certain test papers, as was long ago shown by M. Chevreul, besides this it has no odor like carbolic acid, which odor often disturbs the sick. Lastly, its lack of hurtful effects on mucous membranes, notably of the bladder, has been and is daily demonstrated in the hospitals of Paris. The following is the occasion upon which it was first used. The Academy may remember that I stated before it, and the fact has never been denied, that ammoniacal urine is always produced by a microscopic organism, entirely similar in many respects to the organism of furuncles. Later, in a joint investigation with M. Joubert, we found that a solution of boric acid was easily fatal to these organisms. After that, in 1877, I induced Dr. Guyon, in charge of the genito-urinary clinic at the Necker hospital, to try injections of a solution of boric acid in affections of the bladder. I am informed by this skilful practitioner that he has done so, and daily observes good results from it. He also tells me that he performs no operation of lithotrity without the use of similar injections. I recall these facts to show that a solution of boric acid is entirely harmless to an extremely delicate mucous membrane, that of the bladder, and that it is possible to fill the bladder with a warm solution of boric acid without even inconvenience. To return to the confinement cases. Would it not be of great service to place a warm concentrated solution of boric acid, and compresses, at the bedside of each patient; which she could renew frequently after saturating with the solution, and this also after confinement. It would also be acting the part of prudence to place the compresses, before using, in a hot air oven at 150 degrees C., more than enough to kill the germs of the common organisms. [Footnote: The adoption of precautions, similar to those here suggested, has resulted in the practically complete disappearance of puerperal fevor.--Translator.] Was I justified in calling this communication "ON THE EXTENSION OF THE GERM THEORY TO THE ETIOLOGY OF CERTAIN COMMON DISEASES?" I have detailed the facts as they have appeared to me and I have mentioned interpretations of them: but I do not conceal from myself that, in medical territory, it is difficult to support one's self wholly on subjective foundations. I do not forget that Medicine and Veterinary practice are foreign to me. I desire judgment and criticism upon all my contributions. Little tolerant of frivolous or prejudiced contradiction, contemptuous of that ignorant criticism which doubts on principle, I welcome with open arms the militant attack which has a method in doubting and whose rule of conduct has the motto "More light." It is a pleasure once more to acknowledge the helpfulness of the aid given me by Messrs. Chamberland and Roux during the studies I have just recorded. I wish also to acknowledge the great assistance of M. Doleris. PREJUDICES WHICH HAVE RETARDED THE PROGRESS OF GEOLOGY UNIFORMITY IN THE SERIES OF PAST CHANGES IN THE ANIMATE AND INANIMATE WORLD BY SIR CHARLES LYELL INTRODUCTORY NOTE Sir Charles Lyell was born near Kirriemuir, Forfarshire, Scotland, on November 14, 1797. He graduated from Exeter College, Oxford, in 1819, and proceeded to the study of law. Although he practised for a short time, he was much hampered in this profession, as in all his work, by weak eyesight; and after the age of thirty he devoted himself chiefly to science. Lyell's father was a botanist of some distinction, and the son seems to have been interested in natural history from an early age. While still an undergraduate he made geological journeys in Scotland and on the Continent of Europe, and throughout his life he upheld by precept and example the importance of travel for the geologist. The first edition of his "Principles of Geology" was published in 1830; and the phrase used in the sub-title, "an attempt to explain the former changes of the earth's surface, by reference to causes now in action" strikes the keynote of his whole work. All his life he continued to urge this method of explanation in opposition to the hypotheses, formerly much in vogue, which assumed frequent catastrophes to account for geologic changes. The chapters here printed give his own final statement of his views on this important issue. Lyell's scientific work received wide recognition: he was more than once President of the Geological Society, in 1864 was President of the British Association, was knighted in 1848, and made a baronet in 1864. He possessed a broad general culture, and his home was a noted center of the intellectual life of London. He twice came to the United States to lecture, and created great interest. On his death, on February 22, 1875, he was buried in Westminster Abbey. Persistent as were Lyell's efforts for the establishment of his main theory, he remained remarkably open-minded; and when the evolutionary hypothesis was put forward he became a warm supporter of it. Darwin in his autobiography thus sums up Lyell's achievement: "The science of geology is enormously indebted to Lyell--more so, as I believe, than to any other man who ewer lived." THE PROGRESS OF GEOLOGY [Footnote: The text of the two following papers is taken from the 11th edition of Lyell's Principles of Geology, the last edition revised by the author.] I PREPOSSESSIONS IN REGARD TO THE DURATION OF PAST TIME--PREJUDICES ARISING FROM OUR PECULIAR POSITION AS INHABITANTS OF THE LAND-- OTHERS OCCASIONED BY OUR NOT SEEING SUBTERRANEAN CHANGES NOW IN PROGRESS--ALL THESE CAUSES COMBINE TO MAKE THE FORMER COURSE OF NATURE APPEAR DIFFERENT FROM THE PRESENT--OBJECTIONS TO THE DOCTRINE THAT CAUSES SIMILAR IN KIND AND ENERGY TO THOSE NOW ACTING, HAVE PRODUCED THE FORMER CHANGES OF THE EARTH'S SURFACE CONSIDERED If we reflect on the history of the progress of geology we perceive that there have been great fluctuations of opinion respecting the nature of the causes to which all former changes of the earth's surface are referable. The first observers conceived the monuments which the geologist endeavours to decipher to relate to an original state of the earth, or to a period when there were causes in activity, distinct, in a kind and degree, from those now constituting the economy of nature. These views were gradually modified, and some of them entirely abandoned, in proportion as observations were multiplied, and the signs of former mutations were skilfully interpreted. Many appearances, which had for a long time been regarded as indicating mysterious and extraordinary agency, were finally recognised as the necessary result of the laws now governing the material world; and the discovery of this unlooked-for conformity has at length induced some philosophers to infer, that, during the ages contemplated in geology, there has never been any interruption to the agency of the same uniform laws of change. The same assemblage of general causes, they conceive, may have been sufficient to produce, by their various combinations, the endless diversity of effects, of which the shell of the earth has preserved the memorials; and, consistently with these principles, the recurrence of analogous changes is expected by them in time to come. Whether we coincide or not in this doctrine we must admit that the gradual progress of opinion concerning the succession of phenomena in very remote eras, resembles, in a singular manner, that which has accompanied the growing intelligence of every people, in regard to the economy of nature in their own times. In an early state of advancement, when a greater number of natural appearances are unintelligible, an eclipse, an earthquake, a flood, or the approach of a comet, with many other occurrences afterwards found to belong to the regular course of events, are regarded as prodigies. The same delusion prevails as to moral phenomena, and many of these are ascribed to the intervention of demons, ghosts, witches, and other immaterial and supernatural agents. By degrees, many of the enigmas of the moral and physical world are explained, and, instead of being due to extrinsic and irregular causes, they are found to depend on fixed and invariable laws. The philosopher at last becomes convinced of the undeviating uniformity of secondary causes; and, guided by his faith in this principle, he determines the probability of accounts transmitted to him of former occurrences, and often rejects the fabulous tales of former times, on the ground of their being irreconcilable with the experience of more enlightened ages. PREPOSSESSIONS IN REGARD TO THE DURATION OF PAST TIME.--As a belief in the want of conformity in the cause by which the earth's crust has been modified in ancient and modern periods was, for a long time, universally prevalent, and that, too, amongst men who were convinced that the order of nature had been uniform for the last several thousand years, every circumstance which could have influenced their minds and given an undue bias to their opinions deserves particular attention. Now the reader may easily satisfy himself, that, however undeviating the course of nature may have been from the earliest epochs, it was impossible for the first cultivators of geology to come to such a conclusion, so long as they were under a delusion as to the age of the world, and the date of the first creation of animate beings. However fantastical some theories of the sixteenth century may now appear to us,--however unworthy of men of great talent and sound judgment,--we may rest assured that, if the same misconception now prevailed in regard to the memorials of human transactions, it would give rise to a similar train of absurdities. Let us imagine, for example, that Champollion, and the French and Tuscan literati when engaged in exploring the antiquities of Egypt, had visited that country with a firm belief that the banks of the Nile were never peopled by the human race before the beginning of the nineteenth century, and that their faith in this dogma was as difficult to shake as the opinion of our ancestors, that the earth was never the abode of living beings until the creation of the present continents, and of the species now existing,--it is easy to perceive what extravagant systems they would frame, while under the influence of this delusion, to account for the monuments discovered in Egypt. The sight of the pyramids, obelisks, colossal statues, and ruined temples, would fill them with such astonishment, that for a time they would be as men spell-bound--wholly incapable of reasoning with sobriety. They might incline at first to refer the construction of such stupendous works to some superhuman powers of the primeval world. A system might be invented resembling that so gravely advanced by, Manetho, who relates that a dynasty of gods originally ruled in Egypt, of whom Vulcan, the first monarch, reigned nine thousand years; after whom came Hercules and other demigods, who were at last succeeded by human kings. When some fanciful speculations of this kind had amused their imaginations for a time, some vast repository of mummies would be discovered, and would immediately undeceive those antiquaries who enjoyed an opportunity of personally examining them; but the prejudices of others at a distance, who were not eye-witnesses of the whole phenomena, would not be so easily overcome. The concurrent report of many travellers would, indeed, render it necessary for them to accommodate ancient theories to some of the new facts, and much wit and ingenuity would be required to modify and defend their old positions. Each new invention would violate a greater number of known analogies; for if a theory be required to embrace some false principle, it becomes more visionary in proportion as facts are multiplied, as would be the case if geometers were now required to form an astronomical system on the assumption of the immobility of the earth. Amongst other fanciful conjectures concerning the history of Egypt, we may suppose some of the following to be started. 'As the banks of the Nile have been so recently colonized for the first time, the curious substances called mummies could never in reality have belonged to men. They may have been generated by some PLASTIC VIRTUE residing in the interior of the earth, or they may be abortions of Nature produced by her incipient efforts in the work of creation. For if deformed beings are sometimes born even now, when the scheme of the universe is fully developed, many more may have been "sent before their time scarce half made up," when the planet itself was in the embryo state. But if these notions appear to derogate from the perfection of the Divine attributes, and if these mummies be in all their parts true representations of the human form, may we not refer them to the future rather than the past? May we not be looking into the womb of Nature, and not her grave? May not these images be like the shades of the unborn in Virgil's Elysium--the archetypes of men not yet called into existence?' These speculations, if advocated by eloquent writers, would not fail to attract many zealous votaries, for they would relieve men from the painful necessity of renouncing preconceived opinions. Incredible as such scepticism may appear, it has been rivalled by many systems of the sixteenth and seventeenth centuries, and among others by that of the learned Falloppio, who, as we have seen (p. 33), regarded the tusks of fossil elephants as earthly concretions, and the pottery or fragments of vases in the Monte Testaceo, near Rome, as works of nature, and not of art. But when one generation had passed away, and another, not compromised to the support of antiquated dogmas, had succeeded, they would review the evidence afforded by mummies more impartially, and would no longer controvert the preliminary question, that human beings had lived in Egypt before the nineteenth century: so that when a hundred years perhaps had been lost, the industry and talents of the philosopher would be at last directed to the elucidation of points of real historical importance. But the above arguments are aimed against one only of many prejudices with which the earlier geologists had to contend. Even when they conceded that the earth had been peopled with animate beings at an earlier period than was at first supposed, they had no conception that the quantity of time bore so great a proportion to the historical era as is now generally conceded. How fatal every error as to the quantity of time must prove to the introduction of rational views concerning the state of things in former ages, may be conceived by supposing the annals of the civil and military transactions of a great nation to be perused under the impression that they occurred in a period of one hundred instead of two thousand years. Such a portion of history would immediately assume the air of a romance; the events would seem devoid of credibility, and inconsistent with the present course of human affairs. A crowd of incidents would follow each other in thick succession. Armies and fleets would appear to be assembled only to be destroyed, and cities built merely to fall in ruins. There would be the most violent transitions from foreign or intestine war to periods of profound peace, and the works effected during the years of disorder or tranquillity would appear alike superhuman in magnitude. He who should study the monuments of the natural world under the influence of a similar infatuation, must draw a no less exaggerated picture of the energy and violence of causes, and must experience the same insurmountable difficulty in reconciling the former and present state of nature, If we could behold in one view all the volcanic cones thrown up in Iceland, Italy, Sicily, and other parts of Europe, during the last five thousand years, and could see the lavas which have flowed during the same period; the dislocations, subsidences, and elevations caused during earthquakes; the lands added to various deltas, or devoured by the sea, together with the effects of devastation by floods, and imagine that all these events had happened in one year, we must form most exalted ideas of the activity of the agents, and the suddenness of the revolutions. If geologists, therefore, have misinterpreted the signs of a succession of events, so as to conclude that centuries were implied where the characters indicated thousands of years, and thousands of years where the language of Nature signified millions, they could not, if they reasoned logically from such false premises, come to any other conclusion than that the system of the natural world had undergone a complete revolution. We should be warranted in ascribing the erection of the great pyramid to superhuman power, if we were convinced that it was raised in one day; and if we imagine, in the same manner, a continent or mountain-chain to have been elevated during an equally small fraction of the time which was really occupied in upheaving it, we might then be justified in inferring, that the subterranean movements were once far more energetic than in our own times. We know that; during one earthquake the coast of Chili may be raised for a hundred miles to the average height of about three feet. A repetition of two thousand shocks, of equal violence, might produce a mountain-chain one hundred miles long, and six thousand feet high. Now, should one or two only of these convulsions happen in a century, it would be consistent with the order of events experienced by the Chilians from the earliest times: but if the whole of them were to occur in the next hundred years, the entire district must be depopulated, scarcely any animals or plants could survive, and the surface would be one confused heap of ruin and desolation. One consequence of undervaluing greatly the quantity of past time, is the apparent coincidence which it occasions of events necessarily disconnected, or which are so unusual, that it would be inconsistent with all calculation of chances to suppose them to happen at one and the same time. When the unlooked-for association of such rare phenomena is witnessed in the present course of nature, it scarcely ever fails to excite a suspicion of the preternatural in those minds which are not firmly convinced of the uniform agency of secondary causes;--as if the death of some individual in whose fate they are interested happens to be accompanied by the appearance of a luminous meteor, or a comet, or the shock of an earthquake. It would be only necessary to multiply such coincidences indefinitely, and the mind of every philosopher would be disturbed. Now it would be difficult to exaggerate the number of physical events, many of them most rare and unconnected in their nature, which were imagined by the Woodwardian hypothesis to have happened in the course of a few months: and numerous other examples might be found of popular geological theories, which require us to imagine that a long succession of events happened in a brief and almost momentary period. Another liability to error, very nearly allied to the former, arises from the frequent contact of geological monuments referring to very distant periods of time. We often behold, at one glance, the effects of causes which have acted at times incalculably remote, and yet there may be no striking circumstances to mark the occurrence of a great chasm in the chronological series of Nature's archives. In the vast interval of time which may really have elapsed between the results of operations thus compared, the physical condition of the earth may, by slow and insensible modifications, have become entirely altered; one or more races of organic beings may have passed away, and yet have left behind, in the particular region under contemplation, no trace of their existence. To a mind unconscious of these intermediate events, the passage from one state of things to another must appear so violent, that the idea of revolutions in the system inevitably suggests itself. The imagination is as much perplexed by the deception, as it might be if two distant points in space were suddenly brought into immediate proximity. Let us suppose, for a moment, that a philosopher should lie down to sleep in some arctic wilderness, and then be transferred by a power, such as we read of in tales of enchantment, to a valley in a tropical country, where, on awaking, he might find himself surrounded by birds of brilliant plumage, and all the luxuriance of animal and vegetable forms of which Nature is so prodigal in those regions. The most reasonable supposition, perhaps, which he could make, if by the necromancer's art he were placed in such a situation, would be, that he was dreaming; and if a geologist form theories under a similar delusion, we cannot expect him to preserve more consistency in his speculations, than in the train of ideas in an ordinary dream. It may afford, perhaps, a more lively illustration of the principle here insisted upon, if I recall to the reader's recollection the legend of the Seven Sleepers. The scene of that popular fable was placed in the two centuries which elapsed between the reign of the emperor Decius and the death of Theodosius the younger. In that interval of time (between the years 249 and 450 of our era) the union of the Roman empire had been dissolved, and some of its fairest provinces overrun by the barbarians of the north. The seat of government had passed from Rome to Constantinople, and the throne from a pagan persecutor to a succession of Christian and orthodox princes. The genius of the empire had been humbled in the dust, and the altars of Diana and Hercules were on the point of being transferred to Catholic saints and martyrs. The legend relates, 'that when Decius was still persecuting the Christians, seven noble youths of Ephesus concealed themselves in a spacious cavern in the side of an adjacent mountain, where they were doomed to perish by the tyrant, who gave orders that the entrance should be firmly secured with a pile of huge stones. They immediately fell into a deep slumber, which was miraculously prolonged, without injuring the powers of life, during a period of 187 years. At the end of that time the slaves of Adolius, to whom the inheritance of the mountain had descended, removed the stones to supply materials for some rustic edifice: the light of the sun darted into the cavern, and the seven sleepers were permitted to awake. After a slumber, as they thought, of a few hours, they were pressed by the calls of hunger, and resolved that Jamhlichus, one of their number, should secretly return to the city to purchase bread for the use of his companions. The youth could no longer recognise the once familiar aspect of his native country, and his surprise was increased by the appearance of a large cross triumphantly erected over the principal gate of Ephesus. His singular dress and obsolete language confounded the baker, to whom he offered an ancient medal of Decius as the current coin of the empire; and Jamblichus, on the suspicion of a secret treasure, was dragged before the judge. Their mutual enquiries produced the amazing discovery, that two centuries were almost elapsed since Jamblichus and his friends had escaped from the rage of a pagan tyrant.' This legend was received as authentic throughout the Christian world before the end of the sixth century, and was afterwards introduced by Mahomet as a divine revelation into the Koran, and from hence was adopted and adorned by all the nations from Bengal to Africa who professed the Mahometan faith. Some vestiges even of a similar tradition have been discovered in Scandinavia. 'This easy and universal belief,' observes the philosophical historian of the Decline and Fall, 'so expressive of the sense of mankind, may be ascribed to the genuine merit of the fable itself. We imperceptibly advance from youth to age, without observing the gradual, but incessant, change of human affairs; and even, in our larger experience of history, the imagination is accustomed, by a perpetual series of causes and effects, to unite the most distant revolutions. But if the interval between two memorable eras could be instantly annihilated; if it were possible, after a momentary slumber of two hundred years, to display the new world to the eyes of a spectator who still retained a lively and recent impression of the old, his surprise and his reflections would furnish the pleasing subject of a philosophical romance.' [Footnote: Gibbon, Decline and Fall. chap, xxxiii.] PREJUDICES ARISING FROM OUR PECULIAR POSITION AS INHABITANTS OF THE LAND.--The sources of prejudice hitherto considered may be deemed peculiar for the most part to the infancy of the science, but others are common to the first cultivators of geology and to ourselves, and are all singularly calculated to produce the same deception, and to strengthen our belief that the course of Nature in the earlier ages differed widely from that now established. Although these circumstances cannot be fully explained without assuming some things as proved, which it has been my object elsewhere to demonstrate, [Footnote: Elements of Geology, 6th edit., 1865; and Student's Elements, 1871.] it may be well to allude to them briefly in this place. The first and greatest difficulty, then, consists in an habitual unconsciousness that our position as observers is essentially unfavourable, when we endeavour to estimate the nature and magnitude of the changes now in progress. In consequence of our inattention to this subject, we are liable to serious mistakes in contrasting the present with former states of the globe. As dwellers on the land, we inhabit about a fourth part of the surface; and that portion is almost exclusively a theatre of decay, and not of reproduction. We know, indeed, that new deposits are annually formed in seas and lakes, and that every year some new igneous rocks are produced in the bowels of the earth, but we cannot watch the progress of their formation, and as they are only present to our minds by the aid of reflection, it requires an effort both of the reason and the imagination to appreciate duly their importance. It is, therefore, not surprising that we estimate very imperfectly the result of operations thus unseen by us; and that, when analogous results of former epochs are presented to our inspection, we cannot immediately recognise the analogy. He who has observed the quarrying of stone from a rock, and has seen it shipped for some distant port, and then endeavours to conceive what kind of edifice will be raised by the materials, is in the same predicament as a geologist, who, while he is confined to the land, sees the decomposition of rocks, and the transportation of matter by rivers to the sea, and then endeavours to picture to himself the new strata which Nature is building beneath the waters. PREJUDICES ARISING FROM OUR NOT SEEING SUBTERRANEAN CHANGES.--Nor is his position less unfavourable when, beholding a volcanic eruption, he tries to conceive what changes the column of lava has produced, in its passage upwards, on the intersected strata; or what form the melted matter may assume at great depths on cooling; or what may be the extent of the subterranean rivers and reservoirs of liquid matter far beneath the surface. It should, therefore, be remembered, that the task imposed on those who study the earth's history requires no ordinary share of discretion; for we are precluded from collating the corresponding parts of the system of things as it exists now, and as it existed at former periods. If we were inhabitants of another element--if the great ocean were our domain, instead of the narrow limits of the land, our difficulties would be considerably lessened; while, on the other hand, there can be little doubt, although the reader may, perhaps, smile at the bare suggestion of such an idea, that an amphibious being, who should possess our faculties, would still more easily arrive at sound theoretical opinions in geology, since he might behold, on the one hand, the decomposition of rocks in the atmosphere, or the transportation of matter by running water; and, on the other, examine the deposition of sediment in the sea, and the imbedding of animal and vegetable remains in new strata. He might ascertain, by direct observation, the action of a mountain torrent, as well as of a marine current; might compare the products of volcanos poured out upon the land with those ejected beneath the waters; and might mark, on the one hand, the growth of the forest, and, on the other, that of the coral reef. Yet, even with these advantages, he would be liable to fall into the greatest errors, when endeavouring to reason on rocks of subterranean origin. He would seek in vain, within the sphere of his observation, for any direct analogy to the process of their formation, and would therefore be in danger of attributing them, wherever they are upraised to view, to some 'primeval state of nature.' But if we may be allowed so far to indulge the imagination, as to suppose a being entirely confined to the nether world--some 'dusky melancholy sprite,' like Umbriel, who could 'flit on sooty pinions to the central earth,' but who was never permitted to 'sully the fair face of light,' and emerge into the regions of water and of air; and if this being should busy himself in investigating the structure of the globe, he might frame theories the exact converse of those usually adopted by human philosophers. He might infer that the stratified rocks, containing shells and other organic remains, were the oldest of created things, belonging to some original and nascent state of the planet. 'Of these masses' he might say, 'whether they consist of loose incoherent sand, soft clay, or solid stone, none have been formed in modern times. Every year some of them are broken and shattered by earthquakes, or melted by volcanic fire; and when they cool down slowly from a state of fusion, they assume a new and more crystalline form, no longer exhibiting that stratified disposition and those curious impressions and fantastic markings, by which they were previously characterised. This process cannot have been carried on for an indefinite time, for in that case all the stratified rocks would long ere this have been fused and crystallised. It is therefore probable that the whole planet once consisted of these mysterious and curiously bedded formations at a time when the volcanic fire had not yet been brought into activity. Since that period there seems to have been a gradual development of heat; and this augmentation we may expect to continue till the whole globe shall be in a state of fluidity, or shall consist, in those parts which are not melted, of volcanic and crystalline rocks.' Such might be the system of the Gnome at the very time that the followers of Leibnitz, reasoning on what they saw on the outer surface, might be teaching the opposite doctrine of gradual refrigeration, and averring that the earth had begun its career as a fiery comet, and might be destined hereafter to become a frozen mass. The tenets of the schools of the nether and of the upper world would be directly opposed to each other, for both would partake of the prejudices inevitably resulting from the continual contemplation of one class of phenomena to the exclusion of another. Man observes the annual decomposition of crystalline and igneous rocks, and may sometimes see their conversion into stratified deposits; but he cannot witness the reconversion of the sedimentary into the crystalline by subterranean heat. He is in the habit of regarding all the sedimentary rocks as more recent than the unstratified, for the same reason that we may suppose him to fall into the opposite error if he saw the origin of the igneous class only. For more than two centuries the shelly strata of the Subapennine hills afforded matter of speculation to the early geologists of Italy, and few of them had any suspicion that similar deposits were then forming in the neighbouring sea. Some imagined that the strata, so rich in organic remains, instead of being due to secondary agents, had been so created in the beginning of things by the fiat of the Almighty. Others, as we have seen, ascribed the imbedded fossil bodies to some plastic power which resided in the earth in the early ages of the world. In what manner were these dogmas at length exploded? The fossil relics were carefully compared with their living analogues, and all doubts as to their organic origin were eventually dispelled. So, also, in regard to the nature of the containing beds of mud, sand, and limestone: those parts of the bottom of the sea were examined where shells are now becoming annually entombed in new deposits, Donati explored the bed of the Adriatic, and found the closest resemblance between the strata there forming, and those which constituted hills above a thousand feet high in various parts of the Italian peninsula. He ascertained by dredging that living testacea were there grouped together in precisely the same manner as were their fossil analogues in the inland strata; and while some of the recent shells of the Adriatic were becoming incrusted with calcareous rock, be observed that others had been newly buried in sand and clay, precisely as fossil shells occur in the Subapennine hills. In like manner, the volcanic rocks of the Vicentin had been studied in the beginning of the last century; but no geologist suspected, before the time of Arduino, that these were composed of ancient submarine lavas. During many years of controversy, the popular opinion inclined to a belief that basalt and rocks of the same class had been precipitated from a chaotic fluid, or an ocean which rose at successive periods over the continents, charged with the component elements of the rocks in question. Few will now dispute that it would have been difficult to invent a theory more distant from the truth; yet we must cease to wonder that it gained so many proselytes, when we remember that its claims to probability arose partly from the very circumstance of its confirming the assumed want of analogy between geological causes and those now in action. By what train of investigations were geologists induced at length to reject these views, and to assent to the igneous origin of the trappean formations? By an examination of volcanos now active, and by comparing their structure and the composition of their lavas with the ancient trap rocks. The establishment, from time to time, of numerous points of identification, drew at length from geologists a reluctant admission, that there was more correspondence between the condition of the globe at remote eras and now, and more uniformity in the laws which have regulated the changes of its surface, than they at first imagined. If, in this state of the science, they still despaired of reconciling every class of geological phenomena to the operations of ordinary causes, even by straining analogy to the utmost limits of credibility, we might have expected, at least, that the balance of probability would now have been presumed to incline towards the close analogy of the ancient and modern causes. But, after repeated experience of the failure of attempts to speculate on geological monuments, as belonging to a distinct order of things, new sects continued to persevere in the principles adopted by their predecessors. They still began, as each new problem presented itself, whether relating to the animate or inanimate world, to assume an original and dissimilar order of nature; and when at length they approximated, or entirely came round to an opposite opinion, it was always with the feeling, that they were conceding what they had been justified a priori in deeming improbable. In a word, the same men who, as natural philosophers, would have been most incredulous respecting any extraordinary deviations from the known course of nature, if reported to have happened IN THEIR OWN TIME, were equally disposed, as geologists, to expect the proofs of such deviations at every period of the past. * * * * UNIFORMITY OF CHANGE II SUPPOSED ALTERNATE PERIODS OF REPOSE AND DISORDER--OBSERVED FACTS IN WHICH THIS DOCTRINE HAS ORIGINATED--THESE MAY BE EXPLAINED BY SUPPOSING A UNIFORM AND UNINTERRUPTED SERIES OF CHANGES--THREE- FOLD CONSIDERATION OF THIS SUBJECT: FIRST, IN REFERENCE TO THE LAWS WHICH GOVERN THE FORMATION OF FOSSILIFEROUS STRATA, AND THE SHIFTING OF THE AREAS OF SEDIMENTARY DEPOSITION; SECONDLY, IN REFERENCE TO THE LIVING CREATION, EXTINCTION OF SPECIES, AND ORIGIN OF NEW ANIMALS AND PLANTS; THIRDLY, IN REFERENCE TO THE CHANGES PRODUCED IN THE EARTH'S CRUST BY THE CONTINUANCE OF SUBTERRANEAN MOVEMENTS IN CERTAIN AREAS, AND THEIR TRANSFERENCE AFTER LONG PERIODS TO NEW AREAS--ON THE COMBINED INFLUENCE OF ALL THESE MODES AND CAUSES OF CHANGE IN PRODUCING BREAKS AND CHASMS IN THE CHAIN OF RECORDS--CONCLUDING REMARKS ON THE IDENTITY OF THE ANCIENT AND PRESENT SYSTEM OF TERRESTRIAL CHANGES. ORIGIN OF THE DOCTRINE OF ALTERNATE PERIODS OF REPOSE AND DISORDER.--It has been truly observed, that when we arrange the fossiliferous formations in chronological order, they constitute a broken and defective series of monuments: we pass without any intermediate gradations from systems of strata which are horizontal, to other systems which are highly inclined--from rocks of peculiar mineral composition to others which have a character wholly distinct--from one assemblage of organic remains to another, in which frequently nearly all the species, and a large part of the genera, are different. These violations of continuity are so common as to constitute in most regions the rule rather than the exception, and they have been considered by many geologists as conclusive in favour of sudden revolutions in the inanimate and animate world. We have already seen that according to the speculations of some writers, there have been in the past history of the planet alternate periods of tranquillity and convulsion, the former enduring for ages, and resembling the state of things now experienced by man, the other brief, transient, and paroxysmal, giving rise to new mountains, seas, and valleys, annihilating one set of organic beings, and ushering in the creation of another. It will be the object of the present chapter to demonstrate that these theoretical views are not borne out by a fair interpretation of geological monuments. It is true that in the solid framework of the globe we have a chronological chain of natural records, many links of which are wanting: but a careful consideration of all the phenomena leads to the opinion that the series was originally defective--that it has been rendered still more so by time--that a great part of what remains is inaccessible to man, and even of that fraction which is accessible nine-tenths or more are to this day unexplored. The readiest way, perhaps, of persuading the reader that we may dispense with great and sudden revolutions in the geological order of events is by showing him how a regular and uninterrupted series of changes in the animate and inanimate world must give rise to such breaks in the sequence, and such unconformability of stratified rocks, as are usually thought to imply convulsions and catastrophes. It is scarcely necessary to state that the order of events thus assumed to occur, for the sake of illustration, should be in harmony with all the conclusions legitimately drawn by geologists from the structure of the earth, and must be equally in accordance with the changes observed by man to be now going on in the living as well as in the inorganic creation. It may be necessary in the present state of science to supply some part of the assumed course of nature hypothetically; but if so, this must be done without any violation of probability, and always consistently with the analogy of what is known both of the past and present economy of our system. Although the discussion of so comprehensive a subject must carry the beginner far beyond his depth, it will also, it is hoped, stimulate his curiosity, and prepare him to read some elementary treatises on geology with advantage, and teach him the bearing on that science of the changes now in progress on the earth. At the same time it may enable him the better to understand the intimate connection between the Second and Third Books of this work, one of which is occupied with the changes of the inorganic, the latter with those of the organic creation. In pursuance, then, of the plan above proposed, I will consider in this chapter, first, the laws which regulate the denudation of strata and the deposition of sediment; secondly, those which govern the fluctuation in the animate world; and thirdly, the mode in which subterranean movements affect the earth's crust. UNIFORMITY OF CHANGE CONSIDERED, FIRST, IN REFERENCE TO DENUDATION AND SEDIMENTARY DEPOSITION.--First, in regard to the laws governing the deposition of new strata. If we survey the surface of the globe, we immediately perceive that it is divisible into areas of deposition and non-deposition; or, in other words, at any given time there are spaces which are the recipients, others which are not the recipients, of sedimentary matter. No new strata, for example, are thrown down on dry land, which remains the same from year to year; whereas, in many parts of the bottom of seas and lakes, mud, sand, and pebbles are annually spread out by rivers and currents. There are also great masses of limestone growing in some seas, chiefly composed of corals and shells, or, as in the depths of the Atlantic, of chalky mud made up of foraminifera and diatomaceae. As to the dry land, so far from being the receptacle of fresh accessions of matter, it is exposed almost everywhere to waste away. Forests may be as dense and lofty as those of Brazil, and may swarm with quadrupeds, birds, and insects, yet at the end of thousands of years one layer of black mould a few inches thick may be the sole representative of those myriads of trees, leaves, flowers, and fruits, those innumerable bones and skeletons of birds, quadrupeds, and reptiles, which tenanted the fertik region. Should this land be at length submerged, the waves of the sea may wash away in a few hours the scanty covering of mould, and it may merely impart a darker shade of colour to the next stratum of marl, sand, or other matter newly thrown down. So also at the bottom of the ocean where no sediment is accumulating, seaweed, zoophytes, fish, and even shells, may multiply for ages and decompose, leaving no vestige of their form or substance behind. Their decay, in water, although more slow, is as certain and eventually as complete as in the open air. Nor can they be perpetuated for indefinite periods in a fossil state, unless imbedded in some matrix which is impervious to water, or which at least does not allow a free percolation of that fluid, impregnated, as it usually is, with a slight quantity of carbonic or other acid. Such a free percolation may be prevented either by the mineral nature of the matrix itself, or by the superposition of an impermeable stratum; but if unimpeded, the fossil shell or bone will be dissolved and removed, particle after particle, and thus entirely effaced, unless petrifaction or the substitution of some mineral for the organic matter happen to take place. That there has been land as well as sea at all former geological periods, we know from the fact that fossil trees and terrestrial plants are imbedded in rocks of every age, except those which are so ancient as to be very imperfectly known to us. Occasionally lacustrine and fluviatile shells, or the bones of amphibious or land reptiles, point to the same conclusion. The existence of dry land at all periods of the past implies, as before mentioned, the partial deposition of sediment, or its limitation to certain areas; and the next point to which I shall call the reader's attention is the shifting of these areas from one region to another. First, then, variations in the site of sedimentary deposition are brought about independently of subterranean movements. There is always a slight change from year to year, or from century to century. The sediment of the Rhone, for example, thrown into the Lake of Geneva, is now conveyed to a spot a mile and a half distant from that where it accumulated in the tenth century, and six miles from the point where the delta began originally to form. We may look forward to the period when this lake will be filled up, and then the distribution of the transported matter will be suddenly altered, for the mud and sand brought down from the Alps will thenceforth, instead of being deposited near Geneva, be carried nearly 200 miles southwards, where the Rhone enters the Mediterranean. In the deltas of large rivers, such as those of the Ganges and Indus, the mud is first carried down for many centuries through one arm, and on this being stopped up it is discharged by another, and may then enter the sea at a point 50 or 100 miles distant from its first receptacle. The direction of marine currents is also liable to be changed by various accidents, as by the heaping up of new sandbanks, or the wearing away of cliffs and promontories. But, secondly, all these causes of fluctuation in the sedimentary areas are entirely subordinate to those great upward or downward movements of land, which will presently be spoken of, as prevailing over large tracts of the globe. By such elevation or subsidence certain spaces are gradually submerged, or made gradually to emerge: in the one case sedimentary deposition may be suddenly renewed after having been suspended for one or more geological periods, in the other as suddenly made to cease after having continued for ages. If deposition be renewed after a long interval, the new strata will usually differ greatly from the sedimentary rocks previously formed in the same place, and especially if the older rocks have suffered derangement, which implies a change in the physical geography of the district since the previous conveyance of sediment to the same spot. It may happen, however, that, even where the two groups, the superior and the inferior, are horizontal and conformable to each other, they may still differ entirely in mineral character, because, since the origin of the older formation, the geography of some distant country has been altered. In that country rocks before concealed may have become exposed by denudation; volcanos may have burst out and covered the surface with scoriae and lava; or new lakes, intercepting the sediment previously conveyed from the upper country, may have been formed by subsidence; and other fluctuations may have occurred, by which the materials brought down from thence by rivers to the sea have acquired a distinct mineral character. It is well known that the stream of the Mississippi is charged with sediment of a different colour from that of the Arkansas and Red Rivers, which are tinged with red mud, derived from rocks of porphyry and red gypseous clays in 'the far west.' The waters of the Uruguay, says Darwin, draining a granitic country, are clear and black, those of the Parana, red. [Footnote: Darwin's Journal, p. 163, and edit., p. 139.] The mud with which the Indus is loaded, says Burnes, is of a clayey hue, that of the Chenab, on the other hand, is reddish, that of the Sutlej is more pale. [Footnote: Journ. Roy. Geograph. Soc., vol. iii, p. 142.] The same causes which make these several rivers, sometimes situated at no great distance the one from the other, to differ greatly in the character of their sediment, will make the waters draining the same country at different epochs, especially before and after great revolutions in physical geography, to be entirely dissimilar. It is scarcely necessary to add that marine currents will be affected in an analogous manner in consequence of the formation of new shoals, the emergence of new islands, the subsidence of others, the gradual waste of neighbouring coasts, the growth of new deltas, the increase of coral reefs, volcanic eruptions, and other changes. UNIFORMITY OF CHANGE CONSIDERED, SECONDLY, IN REGERENCE TO THE LIVING CREATION.--Secondly, in regard to the vicissitudes of the living creation, all are agreed that the successive groups of sedimentary strata found in the earth's crust are not only dissimilar in mineral composition for reasons above alluded to, but are likewise distinguishable from each other by their organic remains. The general inference drawn from the study and comparison of the various groups, arranged in chronological order, is this: that at successive periods distinct tribes of animals and plants have inhabited the land and waters, and that the organic types of the newer formations are more analogous to species now existing than those of more ancient rocks. If we then turn to the present state of the animate creation, and enquire whether it has now become fixed and stationary, we discover that, on the contrary, it is in a state of continual flux--that there are many causes in action which tend to the extinction of species, and which are conclusive against the doctrine of their unlimited durability. There are also causes which give rise to new varieties and races in plants and animals, and new forms are continually supplanting others which had endured for ages. But natural history has been sucessfully cultivated for so short a period, that a few examples only of local, and perhaps but one or two of absolute, extirpation of species can as yet be proved, and these only where the interference of man has been conspicuous. It will nevertheless appear evident, from the facts and arguments detailed in the chapters which treat of the geographical distribution of species in the next volume, that man is not the only exterminating agent; and that, independently of his intervention, the annihilation of species is promoted by the multiplication and gradual diffusion of every animal or plant. It will also appear that every alteration in the physical geography and climate of the globe cannot fail to have the same tendency. If we proceed still farther, and enquire whether new species are substituted from time to time for those which die out, we find that the successive introduction of new forms appears to have been a constant part of the economy of the terrestrial system, and if we have no direct proof of the fact it is because the changes take place so slowly as not to come within the period of exact scientific observation. To enable the reader to appreciate the gradual manner in which a passage may have taken place from an extinct fauna to that now living, I shall say a few words on the fossils of successive Tertiary periods. When we trace the series of formations from the more ancient to the more modern, it is in these Tertiary deposits that we first meet with assemblages of organic remains having a near analogy to the fauna of certain parts of the globe in our own time. In the Eocene, or oldest subdivisions, some few of the testacea belong to existing species, although almost all of them, and apparently all the associated vertebrata, are now extinct. These Eocene strata are succeeded by a great number of more modern deposits, which depart gradually in the character of their fossils from the Eocene type, and approach more and more to that of the living creation. In the present state of science, it is chiefly by the aid of shells that we are enabled to arrive at these results, for of all classes the testacea are the most generally diffused in a fossil state, and may be called the medals principally employed by nature in recording the chronology of past events. In the Upper Miocene rocks (No. 5 of the table, p. 135) we begin to find a considerable number, although still a minority, of recent species, intermixed with some fossils common to the preceding, or Eocene, epoch. We then arrive at the Pliocene strata, in which species now contemporary with man begin to preponderate, and in the newest of which nine-tenths of the fossils agree with species still inhabiting the neighbouring sea. It is in the Post-Tertiary strata, where all the shells agree with species now living, that we have discovered the first or earliest known remains of man associated with the bones of quadrupeds, some of which are of extinct species. In thus passing from the older to the newer members of the Tertiary system, we meet with many chasms, but none which separate entirely, by a broad line of demarcation, one state of the organic world from another. There are no signs of an abrupt termination of one fauna and flora, and the starting into life of new and wholly distinct forms. Although we are far from being able to demonstrate geologically an insensible transition from the Eocene to the Miocene, or even from the latter to the recent fauna, yet the more we enlarge and perfect our general survey, the more nearly do we approximate to such a continuous series, and the more gradually are we conducted from times when many of the genera and nearly all the species were extinct, to those in which scarcely a single species flourished which we do not know to exist at present. Dr. A. Philippi, indeed, after an elaborate comparison of the fossil tertiary shells of Sicily with those now living in the Mediterranean, announced, as the result of his examination, that there are strata in that island which attest a very gradual passage from a period when only thirteen in a hundred of the shells were like the species now living in the sea, to an era when the recent species had attained a proportion of ninety-five in a hundred. There is, therefore, evidence, he says, in Sicily of this revolution in the animate world having been effected 'without the intervention of any convulsion or abrupt changes, certain species having from time to time died out and others having been introduced, until at length the existing fauna was elaborated.' In no part of Europe is the absence of all signs of man or his works, in strata of comparatively modern date, more striking than in Sicily. In the central parts of that island we observe a lofty table-land and hills, sometimes rising to the height of 3,000 feet, capped with a limestone, in which from 70 to 85 per cent of the fossil testacea are specifically identical with those now inhabiting the Mediterranean. These calcareous and other argillaceous strata of the same age are intersected by deep valleys which appear to have been gradually formed by denudation, but have not varied materially in width or depth since Sicily was first colonised by the Greeks. The limestone, moreover, which is of so late a date in geological chronology, was quarried for building those ancient temples of Girgenti and Syracuse, of which the ruins carry us back to a remote era in human history. If we are lost in conjectures when speculating on the ages required to lift up these formations to the height of several thousand feet above the sea, and to excavate the valleys, how much more remote must be the era when the same rocks were gradually formed beneath the waters! The intense cold of the Glacial period was spoken of in the tenth chapter. Although we have not yet succeeded in detecting proofs of the origin of man antecedently to that epoch, we have yet found evidence that most of the testacea, and not a few of the quadrupeds, which preceded, were of the same species as those which followed the extreme cold. To whatever local disturbances this cold may have given rise in the distribution of species, it seems to have done little in effecting their annihilation. We may conclude therefore, from a survey of the tertiary and modern strata, which constitute a more complete and unbroken series than rocks of older date, that the extinction and creation of species have been, and are, the result of a slow and gradual change in the organic world. UNIFORMITY OF CHANGE CONSIDERED, THIRDLY, IN REFERENCE TO SUBTERRANEAN MOVEMENTS.--Thirdly, to pass on to the last of the three topics before proposed for discussion, the reader will find, in the account given in the Second Book, Vol. II., of the earthquakes recorded in history, that certain countries have from time immemorial, been rudely shaken again and again; while others, comprising by far the largest part of the globe, have remained to all appearance motionless. In the regions of convulsion rocks have been rent asunder, the surface has been forced up into ridges, chasms have opened, or the ground throughout large spaces has been permanently lifted up above or let down below its former level. In the regions of tranquillity some areas have remained at rest, but others have been ascertained, by a comparison of measurements made at different periods, to have risen by an insensible motion, as in Sweden, or to have subsided very slowly, as in Greenland. That these same movements, whether ascending or descending, have continued for ages in the same direction has been established by historical or geological evidence. Thus we find on the opposite coasts of Sweden that brackish water deposits, like those now forming in the Baltic, occur on the eastern side, and upraised strata filled with purely marine shells, now proper to the ocean, on the western coast. Both of these have been lifted up to an elevation of several hundred feet above high-water mark. The rise within the historical period has not amounted to many yards, but the greater extent of antecedent upheaval is proved by the occurrence in inland spots, several hundred feet high, of deposits filled with fossil shells of species now living either in the ocean or the Baltic. It must in general be more difficult to detect proofs of slow and gradual subsidence than of elevation, but the theory which accounts for the form of circular coral reefs and lagoon islands, and which will be explained in the concluding chapter of this work, will satisfy the reader that there are spaces on the globe, several thousand miles in circumference, throughout which the downward movement has predominated for ages, and yet the land has never, in a single instance, gone down suddenly for several hundred feet at once. Yet geology demonstrates that the persistency of subterranean movements in one direction has not been perpetual throughout all past time. There have been great oscillations of level, by which a surface of dry land has been submerged to a depth of several thousand feet, and then at a period long subsequent raised again and made to emerge. Nor have the regions now motionless been always at rest; and some of those which are at present the theatres of reiterated earthquakes have formerly enjoyed a long continuance of tranquillity. But, although disturbances have ceased after having long prevailed, or have recommenced after a suspension for ages, there has been no universal disruption of the earth's crust or desolation of the surface since times the most remote. The non-occurrence of such a general convulsion is proved by the perfect horizontality now retained by some of the most ancient fossiliferous strata throughout wide areas. That the subterranean forces have visited different parts of the globe at successive periods is inferred chiefly from the unconformability of strata belonging to groups of different ages. Thus, for example, on the borders of Wales and Shropshire, we find the slaty beds of the ancient Silurian system inclined and vertical, while the beds of the overlying carboniferous shale and sandstone are horizontal. All are agreed that in such a case the older set of strata had suffered great disturbance before the deposition of the newer or carboniferous beds, and that these last have never since been violently fractured, nor have ever been bent into folds, whether by sudden or continuous lateral pressure. On the other hand, the more ancient or Silurian group suffered only a local derangement, and neither in Wales nor elsewhere are all the rocks of that age found to be curved or vertical. In various parts of Europe, for example, and particularly near Lake Wener in the south of Sweden, and in many parts of Russia, the Silurian strata maintain the most perfect horizontality; and a similar observation may be made respecting limestones and shales of like antiquity in the great lake district of Canada and the United States. These older rocks are still as flat and horizontal as when first formed; yet, since their origin, not only have most of the actual mountain-chains been uplifted, but some of the very rocks of which those, mountains are composed have been formed, some of them by igneous and others by aqueous action. It would be easy to multiply instances of similar unconformability in formations of other ages; but a few more will suffice. The carboniferous rocks before alluded to as horizontal on the borders of Wales are vertical in the Mendip hills in Somersetshire, where the overlying beds of the New Red Sandstone are horizontal. Again, in the Wolds of Yorkshire the last- mentioned sandstone supports on its curved and inclined beds the horizontal Chalk. The Chalk again is vertical on the flanks of the Pyrenees, and the tertiary strata repose unconformably upon it. As almost every country supplies illustrations of the same phenomena, they who advocate the doctrine of alternate periods of disorder and repose may appeal to the facts above described, as proving that every district has been by turns convulsed by earthquakes and then respited for ages from convulsions. But so it might with equal truth be affirmed that every part of Europe has been visited alternately by winter and summer, although it has always been winter and always summer in some part of the planet, and neither of these seasons has ever reigned simultaneously over the entire globe. They have been always shifting from place to place; but the vicissitudes which recur thus annually in a single spot are never allowed to interfere with the invariable uniformity of seasons throughout the whole planet. So, in regard to subterranean movements, the theory of the perpetual uniformity of the force which they exert on the earth's crust is quite consistent with the admission of their alternate development and suspension for long and indefinite periods within limited geographical areas. If, for reasons before stated, we assume a continual extinction of species and appearance of others on the globe, it will then follow that the fossils of strata formed at two distant periods on the same spot will differ even more certainly than the mineral composition of those strata. For rocks of the same kind have sometimes been reproduced in the same district after a long interval of time; whereas all the evidence derived from fossil remains is in favour of the opinion that species which have once died out have never been reproduced. The submergence, then, of land must be often attended by the commencement of a new class of sedimentary deposits, characterized by a new set of fossil animals and plants, while the reconversion of the bed of the sea into land may arrest at once and for an indefinite time the formation of geological monuments. Should the land again sink, strata will again be formed; but one or many entire revolutions in animal or vegetable life may have been completed in the interval. As to the want of completeness in the fossiliferous series, which may be said to be almost universal, we have only to reflect on what has been already said of the laws governing sedimentary deposition, and those which give rise to fluctuations in the animate world, to be convinced that a very rare combination of circumstances can alone give rise to such a superposition and preservation of strata as will bear testimony to the gradual passage from one state of organic life to another. To produce such strata nothing less will be requisite than the fortunate coincidence of the following conditions: first, a never-failing supply of sediment in the same region throughout a period of vast duration; secondly, the fitness of the deposit in every part for the permanent preservation of imbedded fossils; and, thirdly, a gradual subsidence to prevent the sea or lake from being filled up and converted into land. It will appear in the chapter on coral reefs, that, in certain parts of the Pacific and Indian Oceans, most of these conditions, if not all, are complied with, and the constant growth of coral, keeping pace with the sinking of the bottom of the sea, seems to have gone on so slowly, for such indefinite periods, that the signs of a gradual change in organic life might probably be detected in that quarter of the globe if we could explore its submarine geology. Instead of the growth of coralline limestone, let us suppose, in some other place, the continuous deposition of fluviatile mud and sand, such as the Ganges and Brahmapootra have poured for thousands of years into the Bay of Bengal. Part of this bay, although of considerable depth, might at length be filled up before an appreciable amount of change was effected in the fish, mollusca, and other inhabitants of the sea and neighbouring land. But if the bottom be lowered by sinking at the same rate that it is raised by fluviatile mud, the bay can never be turned into dry land. In that case one new layer of matter may be superimposed upon another for a thickness of many thousand feet, and the fossils of the inferior beds may differ greatly from those entombed in the uppermost, yet every intermediate gradation may be indicated in the passage from an older to a newer assemblage of species. Granting, however, that such an unbroken sequence of monuments may thus be elaborated in certain parts of the sea, and that the strata happen to be all of them well adapted to preserve the included fossils from decomposition, how many accidents must still concur before these submarine formations will be laid open to our investigation! The whole deposit must first be raised several thousand feet, in order to bring into view the very foundation; and during the process of exposure the superior beds must not be entirely swept away by denudation. In the first place, the chances are nearly as three to one against the mere emergence of the mass above the waters, because nearly three-fourths of the globe are covered by the ocean. But if it be upheaved and made to constitute part of the dry land, it must also, before it can be available for our instruction, become part of that area already surveyed by geologists. In this small fraction of land already explored, and still very imperfectly known, we are required to find a set of strata deposited under peculiar conditions, and which, having been originally of limited extent, would have been probably much lessened by subsequent denudation. Yet it is precisely because we do not encounter at every step the evidence of such gradations from one state of the organic world to another, that so many geologists have embraced the doctrine of great and sudden revolutions in the history of the animate world. Not content with simply availing themselves, for the convenience of classification, of those gaps and chasms which here and there interrupt the continuity of the chronological series, as at present known, they deduce, from the frequency of these breaks in the chain of records, an irregular mode of succession in the events themselves, both in the organic and inorganic world. But, besides that some links of the chain which once existed are now entirely lost and others concealed from view, we have good reason to suspect that it was never complete originally. It may undoubtedly be said that strata have been always forming somewhere, and therefore at every moment of past time Nature has added a page to her archives; but, in reference to this subject, it should be remembered that we can never hope to compile a consecutive history by gathering together monuments which were originally detached and scattered over the globe. For, as the species of organic beings contemporaneously inhabiting remote regions are distinct, the fossils of the first of several periods which may be preserved in any one country, as in America for example, will have no connection with those of a second period found in India, and will therefore no more enable us to trace the signs of a gradual change in the living creation, than a fragment of Chinese history will fill up a blank in the political annals of Europe. The absence of any deposits of importance containing recent shells in Chili, or anywhere on the western coast of South America, naturally led Mr. Darwin to the conclusion that "where the bed of the sea is either stationary or rising, circumstances are far less favourable than where the level is sinking to the accumulation of conchiferous strata of sufficient thickness and extension to resist the average vast amount of denudation." [Footnote: Darwin's S. America, pp. 136, 139.] In like manner the beds of superficial sand, clay, and gravel, with recent shells, on the coasts of Norway and Sweden, where the land has risen in Post-tertiary times, are so thin and scanty as to incline us to admit a similar proposition. We may in fact assume that in all cases where the bottom of the sea has been undergoing continuous elevation, the total thickness of sedimentary matter accumulating at depths suited to the habitation of most of the species of shells can never be great, nor can the deposits be thickly covered by superincumbent matter, so as to be consolidated by pressure. When they are upheaved, therefore, the waves on the beach will bear down and disperse the loose materials; whereas, if the bed of the sea subsides slowly, a mass of strata, containing abundance of such species as live at moderate depths, may be formed and may increase in thickness to any amount. It may also extend horizontally over a broad area, as the water gradually encroaches on the subsiding land. Hence it will follow that great violations of continuity in the chronological series of fossiliferous rocks will always exist, and the imperfection of the record, though lessened, will never be removed by future discoveries. For not only will no deposits originate on the dry land, but those formed in the sea near land, which is undergoing constant upheaval, will usually be too slight in thickness to endure for ages. In proportion as we become acquainted with larger geographical areas, many of the gaps, by which a chronological table, like that given at page 135, is rendered defective, will be removed. We were enabled by aid of the labours of Prof. Sedgwick and Sir Roderick Murchison to intercalate, in 1838, the marine strata of the Devonian period, with their fossil shells, corals, and fish, between the Silurian and Carboniferous rocks. Previously the marine fauna of these last- mentioned formations wanted the connecting links which now render the passage from the one to the other much less abrupt. In like manner the Upper Miocene has no representative in England, but in France, Germany, and Switzerland it constitutes a most instructive link between the living creation and the middle of the great Tertiary period. Still we must expect, for reasons before stated, that chasms will for ever continue to occur, in some parts of our sedimentary series. Concluding remarks on the consistency of the theory of gradual change with the existence of great breaks in the series.--To return to the general argument pursued in this chapter, it is assumed, for reasons above explained, that a slow change of species is in simultaneous operation everywhere throughout the habitable surface of sea and land; whereas the fossilisation of plants and animals is confined to those areas where new strata are produced. These areas, as we have seen, are always shifting their position, so that the fossilising process, by means of which the commemoration of the particular state of the organic world, at any given time, is effected, may be said to move about, visiting and revisiting different tracts in succession. To make still more clear the supposed working of this machinery, I shall compare it to a somewhat analogous case that might be imagined to occur in the history of human affairs. Let the mortality of the population of a large country represent the successive extinction of species, and the births of new individuals the introduction of new species. While these fluctuations are gradually taking place everywhere, suppose commissioners to be appointed to visit each province of the country in succession, taking an exact account of the number, names, and individual peculiarities of all the inhabitants, and leaving in each district a register containing a record of this information. If, after the completion of one census, another is immediately made on the same plan, and then another, there will at last be a series of statistical documents in each province. When those belonging to any one province are arranged in chronological order, the contents of such as stand next to each other will differ according to the length of the intervals of time between the taking of each census. If, for example, there are sixty provinces, and all the registers are made in a single year and renewed annually, the number of births and deaths will be so small, in proportion to the whole of the inhabitants, during the interval between the compiling of two consecutive documents, that the individuals described in such documents will be nearly identical; whereas, if the survey of each of the sixty provinces occupies all the commissioners for a whole year, so that they are unable to revisit the same place until the expiration of sixty years, there will then be an almost entire discordance between the persons enumerated in two consecutive registers in the same province. There are, undoubtedly, other causes, besides the mere quantity of time, which may augment or diminish the amount of discrepancy. Thus, at some periods a pestilential disease may have lessened the average duration of human life; or a variety of circumstances may have caused the births to be unusually numerous, and the population to multiply; or a province may be suddenly colonised by persons migrating from surrounding districts. These exceptions may be compared to the accelerated rate of fluctuations in the fauna and flora of a particular region, in which the climate and physical geography may be undergoing an extraordinary degree of alteration. But I must remind the reader that the case above proposed has no pretensions to be regarded as an exact parallel to the geological phenomena which I desire to illustrate; for the commissioners are supposed to visit the different provinces in rotation; whereas the commemorating processes by which organic remains become fossilised, although they are always shifting from one area to the other, are yet very irregular in their movements. They may abandon and revisit many spaces again and again, before they once approach another district; and, besides this source of irregularity, it may often happen that, while the depositing process is suspended, denudation may take place, which may be compared to the occasional destruction by fire or other causes of some of the statistical documents before mentioned. It is evident that where such accidents occur the want of continuity in the series may become indefinitely great, and that the monuments which follow next in succession will by no means be equidistant from each other in point of time. If this train of reasoning be admitted, the occasional distinctness of the fossil remains, in formations immediately in contact, would be a necessary consequence of the existing laws of sedimentary deposition and subterranean movement, accompanied by a constant dying-out and renovation of 'species. As all the conclusions above insisted on are directly opposed to opinions still popular, I shall add another comparison, in the hope of preventing any possible misapprehension of the argument. Suppose we had discovered two buried cities at the foot of Vesuvius, immediately superimposed upon each other, with a great mass of tuff and lava intervening, just as Portici and Resina, if now covered with ashes, would overlie Herculaneum. An antiquary might possibly be entitled to infer, from the inscriptions on public edifices, that the inhabitants of the inferior and older city were Greeks, and those of the modern towns Italians. But he would reason vary hastily if he also concluded from these data, that there had been a sudden change from the Greek to the Italian language in Campania. But if he afterwards found three buried cities, one above the other, the intermediate one being Roman, while, as in the former example, the lowest was Greek and the uppermost Italian, he would then perceive the fallacy of his former opinion, and would begin to suspect that the catastrophes, by which the cities were inhumed might have no relation whatever to the fluctuations in the language of the inhabitants; and that, as the Roman tongue had evidently intervened between the Greek and Italian, so many other dialects may have been spoken in succession, and the passage from the Greek to the Italian may have been very gradual, some terms growing obsolete, while others were introduced from time to time. If this antiquary could have shown that the volcanic paroxysms of Vesuvius were so governed as that cities should be buried one above the other, just as often as any variation occurred in the language of the inhabitants, then, Indeed, the abrupt passage from a Greek to a Roman, and from a Roman to an Italian city, would afford proof of fluctuations no less sudden in the language of the people. So, in Geology, if we could assume that it is part of the plan of Nature to preserve, in every region of the globe, an unbroken series of monuments to commemorate the vicissitudes of the organic creation, we might infer the sudden extirpation of species, and the simultaneous introduction o! others, as often as two formations in contact are found to include dissimilar organic fossils. But we must shut our eyes to the whole economy of the existing causes, aqueous, igneous, and organic, if we fail to perceive that such is not the plan of Nature. I shall now conclude the discussion of a question with which we have been occupied since the beginning of the fifth chapter--namely, whether there has been any interruption, from the remotest periods, of one uniform and continuous system of change in the animate and inanimate world. We were induced to enter into that enquiry by reflecting how much the progress of opinion in Geology had been influenced by the assumption that the analogy was slight in kind, and still more slight in degree, between the cases which produced the former revolutions of the globe, and those now in every-day operation. It appeared clear that the earlier geologists had not only a scanty acquaintance with existing changes, but were singularly unconscious of the amount of their ignorance. With the presumption naturally inspired by this unconsciousness, they had no hesitation in deciding at once that time could never enable the existing powers of nature to work out changes of great magnitude, still less such important revolutions as those which are brought to light by Geology. They therefore felt themselves at liberty to indulge their imaginations in guessing at what might be, rather than enquiring what is; in other words, they employed themselves in conjecturing what might have been the course of Nature at a remote period, rather than in the investigation of what was the course of Nature in their own times. It appeared to them far more philosophical to speculate on the possibilities of the past, than patiently to explore the realities of the present; and having invented theories under the influence of such maxims, they were consistently unwilling to test their validity by the criterion of their accordance with the ordinary operations of Nature. On the contrary. the claims of each new hypothesis to credibility appeared enhanced by the great contrast, in kind or intensity, of the causes referred to and those now in operation. Never was there a dogma more calculated to foster indolence, and to blunt the keen edge of curiosity, than this assumption of the discordance between the ancient and existing causes of change. It produced a state of mind unfavourable in the highest degree to the candid reception of the evidence of those minute but incessant alterations which every part of the earth's surface is undergoing, and by which the condition of its living inhabitants is continually made to vary. The student, instead of being encouraged with the hope of interpreting the enigmas presented to him in the earth's structure--instead of being prompted to undertake laborious enquiries into the natural history of the organic world, and the complicated effects of the igneous and aqueous causes now in operation--was taught to despond from the first. Geology, it was affirmed, could never rise to the rank of an exact science; the greater number of phenomena must for ever remain inexplicable, or only be partially elucidated by ingenious conjectures. Even the mystery which invested the subject was said to constitute one of its principal charms, affording, as it did, full scope to the fancy to indulge in a boundless field of speculation. The course directly opposed to this method of philosophising consists in an earnest and patient enquiry, how far geological appearances are reconcilable with the effect of changes now in progress, or which may be in progress in regions inaccessible to us, but of which the reality is attested by volcanos and subterranean movements. It also endeavours to estimate the aggregate result of ordinary operations multiplied by time, and cherishes a sanguine hope that the resources to be derived from observation and experiment, or from the study of Nature such as she now is, are very far from being exhausted. For this reason all theories are rejected which involve the assumption of sudden and violent catastrophes and revolutions of the whole earth, and its inhabitants--theories which are restrained by no reference to existing analogies, and in which a desire is manifested to cut, rather than patiently to untie, the Gordian knot. We have now, at least, the advantage of knowing, from experience, that an opposite method has always put geologists on the road that leads to truth--suggesting views which, although imperfect at first, have been found capable of improvement, until at last adopted by universal consent; while the method of speculating on a former distinct state of things and causes has led invariably to a multitude of contradictory systems, which have been overthrown one after the other--have been found incapable of modification--and which have often required to be precisely reversed. The remainder of this work will be devoted to an investigation of the changes now going on in the crust of the earth and its inhabitants. The importance which the student will attach to such researches will mainly depend on the degree of confidence which he feels in the principles above expounded. If he firmly believes in the resemblance or identity of the ancient and present system of terrestrial changes, he will regard every fact collected respecting the cause in diurnal action as affording him a key to the interpretation of some mystery in the past. Events which have occurred at the most distant periods in the animate and inanimate world will be acknowledged to throw light on each other, and the deficiency of our information respecting some of the most obscure parts of the present creation will be removed. For as, by studying the external configuration of the existing land and its inhabitants, we may restore in imagination the appearance of the ancient continents which have passed away, so may we obtain from the deposits of ancient seas and lakes an insight into the nature of the subaqueous processes now in operation, and of many forms of organic life which, though now existing, are veiled from sight. Rocks, also, produced by subterranean fire in former ages, at great depths in the bowels of the earth, present us, when upraised by gradual movements, and exposed to the light of heaven, with an image of those changes which the deep-seated volcano may now occasion in the nether regions. Thus, although we are mere sojourner's on the surface of the planet, chained to a mere point in space, enduring but for a moment of time, the human mind is not only enabled to number worlds beyond the unassisted ken of mortal eye, but to trace the events of indefinite ages before the creation of our race, and is not even withheld from penetrating into the dark secrets of the ocean, or the interior of the solid globe; free, like the spirit which the poet described as animating the universe, ------ire per omnes Terrasque, tractusque maris, ccelumque profisndutn. [Footnote: "To go through all binds, and the tracts of the ocean, and the boundless heaven."] 
27600	----	Note: Project Gutenberg also has an HTML version of this file which includes the original illustrations. See 27600-h.htm or 27600-h.zip: (http://www.gutenberg.net/dirs/2/7/6/0/27600/27600-h/27600-h.htm) or (http://www.gutenberg.net/dirs/2/7/6/0/27600/27600-h.zip) Transcriber's note A few typographical errors have been corrected: they are listed at the end of the text. ZOONOMIA; OR, THE LAWS OF ORGANIC LIFE. VOL. II. _By ERASMUS DARWIN, M.D. F.R.S._ AUTHOR OF THE BOTANIC GARDEN. Principiò coelum, ac terras, camposque liquentes, Lucentemque globum lunæ, titaniaque astra, Spiritus intùs alit, totamque infusa per artus Mens agitat molem, et magno se corpore miscet.--VIRG. Æn. vi. Earth, on whose lap a thousand nations tread, And Ocean, brooding his prolific bed, Night's changeful orb, blue pole, and silvery zones, Where other worlds encircle other suns, One Mind inhabits, one diffusive Soul Wields the large limbs, and mingles with the whole. London: Printed for. J. Johnson, in St. Paul's Church-Yard. 1796. Entered at Stationers' Hall. ZOONOMIA; OR, THE LAWS OF ORGANIC LIFE. PART II. CONTAINING A CATALOGUE OF DISEASES DISTRIBUTED INTO NATURAL CLASSES ACCORDING TO THEIR PROXIMATE CAUSES, WITH THEIR SUBSEQUENT ORDERS, GENERA, AND SPECIES, AND WITH THEIR METHODS OF CURE. * * * * * Hæc, ut potero, explicabo; nec tamen, quasi Pythius Apollo, certa ut sint et fixa, quæ dixero; sed ut Homunculus unus e multis probabiliora conjecturâ sequens.--CIC. TUSC. DISP. l. 1. 9. * * * * * PREFACE. All diseases originate in the exuberance, deficiency, or retrograde action, of the faculties of the sensorium, as their proximate cause; and consist in the disordered motions of the fibres of the body, as the proximate effect of the exertions of those disordered faculties. The sensorium possesses four distinct powers, or faculties, which are occasionally exerted, and produce all the motions of the fibrous parts of the body; these are the faculties of producing fibrous motions in consequence of irritation which is excited by external bodies; in consequence of sensation which is excited by pleasure or pain; in consequence of volition which is excited by desire or aversion; and in consequence of association which is excited by other fibrous motions. We are hence supplied with four natural classes of diseases derived from their proximate causes; which we shall term those of irritation, those of sensation, those of volition, and those of association. In the subsequent classification of diseases I have not adhered to the methods of any of those, who have preceded me; the principal of whom are the great names of Sauvages and Cullen; but have nevertheless availed myself, as much as I could, of their definitions and distinctions. The essential characteristic of a disease consists in its proximate cause, as is well observed by Doctor Cullen, in his Nosologia Methodica, T. ii. Prolegom. p. xxix. Similitudo quidem morborum in similitudine causæ eorum proximæ, qualiscunque sit, reverâ consistit. I have taken the proximate cause for the classic character. The characters of the orders are taken from the excess, or deficiency, or retrograde action, or other properties of the proximate cause. The genus is generally derived from the proximate effect. And the species generally from the locality of the disease in the system. Many species in this system are termed genera in the systems of other writers; and the species of those writers are in consequence here termed varieties. Thus in Dr. Cullen's Nosologia the variola or small-pox is termed a genus, and the distinct and confluent kinds are termed species. But as the infection from the distinct kind frequently produces the confluent kind, and that of the confluent kind frequently produces the distinct; it would seem more analogous to botanical arrangement, which these nosologists profess to imitate, to call the distinct and confluent small-pox varieties than species. Because the species of plants in botanical systems propagate others similar to themselves; which does not uniformly occur in such vegetable productions as are termed varieties. In some other genera of nosologists the species have no analogy to each other, either in respect to their proximate cause, or to their proximate effect, though they may he somewhat similar in less essential properties; thus the thin and saline discharge from the nostrils on going into the cold air of a frosty morning, which is owing to the deficient action of the absorbent vessels of the nostrils, is one species; and the viscid mucus discharged from the secerning vessels of the same membrane, when inflamed, is another species of the same genus, Catarrhus. Which bear no analogy either in respect to their immediate cause or to their immediate effect. The uses of the method here offered to the public of classing diseases according to their proximate causes are, first, more distinctly to understand their nature by comparing their essential properties. Secondly, to facilitate the knowledge of the methods of cure; since in natural classification of diseases the species of each genus, and indeed the genera of each order, a few perhaps excepted, require the same general medical treatment. And lastly, to discover the nature and the name of any disease previously unknown to the physician; which I am persuaded will be more readily and more certainly done by this natural system, than by the artificial classifications already published. The common names of diseases are not well adapted to any kind of classification, and least of all to this from their proximate causes. Some of their names in common language are taken from the remote cause, as worms, stone of the bladder; others from the remote effect, as diarrhoea, salivation, hydrocephalus; others from some accidental symptom of the disease, as tooth-ach, head-ach, heart-burn; in which the pain is only a concomitant circumstance of the excess or deficiency of fibrous actions, and not the cause of them. Others again are taken from the deformity occasioned in consequence of the unnatural fibrous motions, which constitute diseases, as tumours, eruptions, extenuations; all these therefore improperly give names to diseases; and some difficulty is thus occasioned to the reader in endeavouring to discover to what class such disorders belong. Another difficulty attending the names of diseases is, that one name frequently includes more than one disease, either existing at the same time or in succession. Thus the pain of the bowels from worms is caused by the increased action of the membrane from the stimulus of those animals; but the convulsions, which sometimes succeed these pains in children, are caused by the consequent volition, and belong to another class. To discover under what class any disease should be arranged, we must first investigate the proximate cause; thus the pain of the tooth-ach is not the cause of any diseased motions, but the effect; the tooth-ach therefore does not belong to the class of Sensation. As the pain is caused by increased or decreased action of the membranes of the tooth, and these actions are owing to the increase or decrease of irritation, the disease is to be placed in the class of irritation. To discover the order it must be inquired, whether the pain be owing to increased or defective motion of the pained membrane; which is known by the concomitant heat or coldness of the part. In tooth-ach without inflammation there is generally a coldness attends the cheek in its vicinity; as may be perceived by the hand of the patient himself, compared with the opposite cheek. Hence odontalgia is found to belong to the order of decreased irritation. The genus and species must be found by inspecting the synopsis of the second order of the class of Irritation. See Class I. 2. 4. 12. This may be further elucidated by considering the natural operation of parturition; the pain is occasioned by the increased action or distention of the vessels of the uterus, in consequence of the stimulus of the fetus; and is therefore caused by increased irritation; but the action of the abdominal muscles in its exclusion are caused by the pain, and belong to the class of increased sensation. See Class II. 1. 1. 12. Hence the difficulty of determining, under what class of diseases parturition should be arranged, consists in there being two kinds of diseased actions comprehended under one word; which have each their different proximate cause. In Sect. XXXIX. 8. 4. and in Class II. 1. 1. 1. we have endeavoured to give names to four links of animal causation, which conveniently apply to the classification of diseases; thus in common nictitation, or winking with the eyes without our attention to it, the increased irritation is the proximate cause; the stimulus of the air on the dry cornea is the remote cause; the closing of the eyelid is the proximate effect; and the diffusion of tears over the eye-ball is the remote effect. In some cases two more links of causation may be introduced; one of them may be termed the pre-remote cause; as the warmth or motion of the atmosphere, which causes greater exhalation from the cornea. And the other the post-remote effect; as the renewed pellucidity of the cornea; and thus six links of causation may be expressed in words. But if amid these remote links of animal causation any of the four powers or faculties of the sensorium be introduced, the reasoning is not just according to the method here proposed; for these powers of the sensorium are always the proximate causes of the contractions of animal fibres; and therefore in true language cannot be termed their remote causes. From this criterion it may always be determined, whether more diseases than one are comprehended under one name; a circumstance which has much impeded the investigation of the causes, and cures of diseases. Thus the term fever, is generally given to a collection of morbid symptoms; which are indeed so many distinct diseases, that sometimes appear together, and sometimes separately; hence it has no determinate meaning, except it signifies simply a quick pulse, which continues for some hours; in which sense it is here used. In naming diseases I have endeavoured to avoid the affectation of making new compound Greek words, where others equally expressive could be procured: as a short periphrasis is easier to be understood, and less burthensome to the memory. In the Methodus Medendi, which is marked by M.M. at the end of many of the species of diseases, the words incitantia, sorbentia, torpentia, &c. refer to the subsequent articles of the Materia Medica, explaining the operations of medicines. The remote causes of many diseases, their periods, and many circumstances concerning them, are treated of in the preceding volume; the descriptions of many of them, which I have omitted for the sake of brevity, may be seen in the Nosologia Methodica of Sauvages, and in the Synopsis Nosologiæ of Dr. Cullen, and in the authors to which they refer. In this arduous undertaking the author solicits the candour of the critical reader; as he cannot but foresee, that many errors will be discovered, many additional species will require to be inserted; and others to be transplanted, or erased. If he could expend another forty years in the practice of medicine, he makes no doubt, but that he could bring this work nearer perfection, and thence render it more worthy the attention of philosophers.----As it is, he is induced to hope, that some advantages will be derived from it to the science of medicine, and consequent utility to the public, and leaves the completion of his plan to the industry of future generations. DERBY, _Jan._ 1, 1796. * * * * * ZOONOMIA. PART II. * * * * * CLASSES OF DISEASES. * * * * * I. DISEASES OF IRRITATION. II. DISEASES OF SENSATION. III. DISEASES OF VOLITION. IV. DISEASES OF ASSOCIATION. * * * * * _The Orders and Genera of the First Class of Diseases._ * * * * * CLASS I. DISEASES OF IRRITATION. ORDO I. _Increased Irritation._ GENERA. 1. With increased actions of the sanguiferous system. 2. With increased actions of the secerning system. 3. With increased actions of the absorbent system. 4. With increased actions of other cavities and membranes. 5. With increased actions of the organs of sense. ORDO II. _Decreased Irritation._ GENERA. 1. With decreased actions of the sanguiferous system. 2. With decreased actions of the secerning system. 3. With decreased actions of the absorbent system. 4. With decreased actions of other cavities and membranes. 5. With decreased actions of the organs of sense. ORDO III. _Retrograde Irritative Motions._ GENERA. 1. Of the alimentary canal. 2. Of the absorbent system. 3. Of the sanguiferous system. * * * * * _The Orders, Genera, and Species, of the First Class of Diseases._ * * * * * CLASS I. DISEASES OF IRRITATION. ORDO I. _Increased Irritation._ GENUS I. _With Increased Actions of the Sanguiferous System._ SPECIES. 1. _Febris irritativa._ Irritative fever. 2. _Ebrietas._ Drunkenness. 3. _Hæmorrhagia arteriosa._ Arterial hæmorrhage. 4. _Hæmoptoe arteriosa._ Spitting of arterial blood. 5. _Hæmorrhagia narium._ Bleeding from the nose. GENUS II. _With Increased Actions of the Secerning System._ SPECIES. 1. _Calor febrilis._ Febrile heat. 2. _Rubor febrilis._ Febrile redness. 3. _Sudor calidus._ Warm sweat. ---- _febrilis._ Sweat in fevers. ---- _a labore._ ---- from exercise. ---- _ab igne._ ---- from fire. ---- _a medicamentis._ ---- from medicines. 4. _Urina uberior colorata._ Copious coloured urine. 5. _Diarrhoea calida._ Warm diarrhoea. ---- _febrilis._ ---- from fever. ---- _crapulosa._ ---- from indigestion. ---- _infantum._ ---- of infants. 6. _Salivatio calida._ ---- salivation. 7. _Catarrhus calidus._ ---- catarrh. 8. _Expectoratio calida._ ---- expectoration. 9. _Exsudatio pone aures._ Discharge behind the ears. 10. _Gonorrhoea calida._ Warm gonorrhoea. 11. _Fluor albus calidus._ ---- fluor albus. 12. _Hæmorrhois alba._ White piles. 13. _Serum e visicatorio._ Discharge from a blister. 14. _Perspiratio foetida._ Fetid perspiration. 15. _Crines novi._ New hairs. GENUS III. _With increased Actions of the Absorbent System._ SPECIES. 1. _Lingua arida._ Dry tongue. 2. _Fauces aridæ._ Dry throat. 3. _Nares aridi._ Dry nostrils. 4. _Expectoratio solida._ Solid expectoration. 5. _Constipatio alvi._ Costiveness. 6. _Cutis arida._ Dry skin. 7. _Urina parcior colorata._ Diminished coloured urine. 8. _Calculus felleus et icterus._ Gall-stone and jaundice. 9. ---- _renis._ Stone of the kidney. 10. ---- _vesicæ._ Stone of the bladder. 11. ---- _arthriticus._ Gout-stone. 12. _Rheumatismus chronicus._ Chronic rheumatism. 13. _Cicatrix vulnerum._ Healing of ulcers. 14. _Corneæ obfuscatio._ Scar on the cornea. GENUS IV. _With increased Actions of other Cavities and Membranes._ SPECIES. 1. _Nictitatio irritativa._ Irritative nictitation. 2. _Deglutitio irritativa._ Irritative deglutition. 3. _Respiratio et tussis._ Respiration and cough. 4. _Exclusio bilis._ Exclusion of the bile. 5. _Dentitio._ Toothing. 6. _Priapismus._ Priapism. 7. _Distensio mamularum._ Distention of the nipples. 8. _Descensus uteri._ Descent of the uterus. 9. _Prolapsus ani._ Descent of the rectum. 10. _Lumbricus._ Round worm. 11. _Tænia._ Tape-worm. 12. _Ascarides._ Thread-worms. 13. _Dracunculus._ Guinea-worm. 14. _Morpiones._ Crab-lice. 15. _Pediculi._ Lice. GENUS V. _With increased Actions of the Organs of Sense._ SPECIES. 1. _Visus acrior._ Acuter sight. 2. _Auditus acrior._ ---- hearing. 3. _Olfactus acrior._ ---- smell. 4. _Gustus acrior._ ---- taste. 5. _Tactus acrior._ ---- touch. 6. _Sensus caloris acrior._ ---- sense of heat. 7. ---- _extensionis acrior._ ---- sense of extension. 8. _Titillatio._ Tickling. 9. _Pruritus._ Itching. 10. _Dolor urens._ Smarting. 11. _Consternatio._ Surprise. ORDO II. _Decreased Irritation._ GENUS I. _With decreased Actions of the Sanguiferous System._ SPECIES. 1. _Febris inirritativa._ Inirritative fever. 2. _Paresis inirritativa._ ---- debility. 3. _Somnus interruptus._ Interrupted sleep. 4. _Syncope._ Fainting. 5. _Hæmorrhagia venosa._ Venous hæmorrhage. 6. _Hæmorrhois cruenta._ Bleeding piles. 7. _Hæmorrhagia renum._ ---- from the kidneys. 8. ---- _hepatis._ ---- from the liver. 9. _Hæmoptoe venosa._ Spitting of venous blood. 10. _Palpitatio cordis._ Palpitation of the heart. 11. _Menorrhagia._ Exuberant menstruation. 12. _Dysmenorrhagia._ Deficient menstruation. 13. _Lochia nimia._ Too great lochia. 14. _Abortio spontanea._ Spontaneous abortion. 15. _Scorbutus._ Scurvy. 16. _Vibices._ Extravasations of blood. 17. _Petechiæ._ Purple spots. GENUS II. _With decreased Actions of the Secerning System._ SPECIES. 1. _Frigus febrile._ Coldness in fevers. ---- _chronicum._ ---- permanent. 2. _Pallor fugitivus._ Paleness fugitive. ---- _permanens._ ---- permanent. 3. _Pus parcius._ Diminished pus. 4. _Mucus parcior._ Diminished mucus. 5. _Urina parcior pallida._ Pale diminished urine. 6. _Torpor hepaticus._ Torpor of the liver. 7. _Torpor pancreatis._ Torpor of the pancreas. 8. _Torpor renis._ Torpor of the kidney. 9. _Punctæ mucosæ vultus._ Mucous spots on the face. 10. _Maculæ cutis fulvæ._ Tawny blots on the skin. 11. _Canities._ Grey hairs. 12. _Callus._ Callus. 13. _Cataracta._ Cataract. 14. _Innutritio ossium._ Innutrition of the bones. 15. _Rachitis._ Rickets. 16. _Spina distortio._ Distortion of the spine. 17. _Claudicatio coxaria._ Lameness of the hip. 18. _Spina protuberans._ Protuberant spine. 19. _Spina bifida._ Divided spine. 20. _Defectus palati._ Defect of the palate. GENUS III. _With decreased Actions of the Absorbent System._ SPECIES. 1. _Mucus faucium frigidus._ Cold mucus from the throat. 2. _Sudor frigidus._ ---- sweat. 3. _Catarrhus frigidus._ ---- catarrh. 4. _Expectoratio frigida._ ---- expectoration. 5. _Urina uberior pallida._ Copious pale urine. 6. _Diarrhoea frigida._ Cold diarrhoea. 7. _Fluor albus frigidus._ ---- fluor albus. 8. _Gonorrhoea frigida._ ---- gonorrhoea. 9. _Hepatis tumor._ Swelling of the liver. 10. _Chlorosis._ Green sickness. 11. _Hydrocele._ Dropsy of the vagina testis. 12. _Hydrocephalus internus._ ---- of the brain. 13. _Ascites._ ---- of the belly. 14. _Hydrothorax._ ---- of the chest. 15. _Hydrops ovarii._ ---- of the ovary. 16. _Anasarca pulmonum._ ---- of the lungs. 17. _Obesitas._ Corpulency. 18. _Splenis tumor._ Swelling of the spleen. 19. _Genu tumor albus._ White swelling of the knee. 20. _Bronchocele._ Swelled throat. 21. _Scrophula._ King's evil. 22. _Schirrus._ Schirrus. 23. ---- _recti._ ---- of the rectum. 24. ---- _urethræ._ ---- of the urethra. 25. ---- _oesophagi._ ---- of the throat. 26. _Lacteorum inirritabilitas._ Inirritability of the lacteals. 27. _Lymphaticorum inirritabilitas._ Inirritability of the lymphatics. GENUS IV. _With decreased Actions of other Cavities and Membranes._ SPECIES. 1. _Sitis calida._ Thirst warm. ---- _frigida._ ---- cold. 2. _Esuries._ Hunger. 3. _Nausea sicca._ Dry Nausea. 4. _Ægritudo ventriculi._ Sickness of stomach. 5. _Cardialgia._ Heart-burn. 6. _Arthritis ventriculi._ Gout of the stomach. 7. _Colica flatulenta._ Flatulent colic. 8. _Colica saturnina._ Colic from lead. 9. _Tympanitis._ Tympany. 10. _Hypochondriasis._ Hypochondriacism. 11. _Cephalæa frigida._ Cold head-ach. 12. _Odontalgia._ Tooth-ach. 13. _Otalgia._ Ear-ach. 14. _Pleurodyne chronica._ Chronical pain of the side. 15. _Sciatica frigida._ Cold sciatica. 16. _Lumbago frigida._ ---- lumbago. 17. _Hysteralgia frigida._ ---- pain of the uterus. 18. _Proctalgia frigida._ ---- pain of the rectum. 19. _Vesicæ felleæ inirritibilitas_ Inirritability of the gall-bladder _et icterus._ and jaundice. GENUS V. _With decreased Actions of the Organs of Sense._ SPECIES. 1. _Stultitia inirritabilis._ Folly from inirritability. 2. _Visus imminutus._ Impaired vision. 3. _Muscæ volitantes._ Dark moving specks. 4. _Strabismus._ Squinting. 5. _Amaurosis._ Palsy of the optic nerve. 6. _Auditus imminutus._ Impaired hearing. 7. _Olfactus imminutus._ ---- smell. 8. _Gustus imminutus._ ---- taste. 9. _Tactus imminutus._ ---- touch. 10. _Stupor._ Stupor. ORDO III. _Retrograde Irritative Motions._ GENUS I. _Of the Alimentary Canal._ SPECIES. 1. _Ruminatio._ Chewing the cud. 2. _Ructus._ Eructation. 3. _Apepsia._ Indigestion, water-qualm. 4. _Vomitus._ Vomiting. 5. _Cholera._ Cholera. 6. _Ileus._ Iliac passion. 7. _Globus hystericus._ Hysteric strangulation. 8. _Vomendi conamen inane._ Vain efforts to vomit. 9. _Borborigmus._ Gurgling of the bowels. 10. _Hysteria._ Hysteric disease. 11. _Hydrophobia._ Dread of water. GENUS II. _Of the Absorbent System._ SPECIES. 1. _Catarrhus lymphaticus._ Lymphatic catarrh. 2. _Salivatio lymphatica._ Lymphatic salivation. 3. _Nausea humida._ Moist nausea. 4. _Diarrhoea lymphatica._ Lymphatic flux. 5. _Diarrhoea chylifera._ Flux of chyle. 6. _Diabætes._ Diabetes. 7. _Sudor lymphaticus._ Lymphatic sweat. 8. _Sudor asthmaticus._ Asthmatic sweat. 9. _Translatio puris._ Translation of matter. 10. ---- _lactis._ ---- of milk. 11. ---- _urinæ._ ---- of urine. GENUS III. _Of the Sanguiferous System._ SPECIES. 1. _Capillarium motus retrogressus._ Retrograde motion of the capillaries. 2. _Palpitatio cordis._ Palpitation of the heart. 3. _Anhelatio spasmodica._ Spasmodic panting. * * * * * CLASS I. DISEASES OF IRRITATION. ORDO I. _Increased Irritation._ GENUS I. _With increased Actions of the Sanguiferous System._ The irritability of the whole, or of part, of our system is perpetually changing; these vicissitudes of irritability and of inirritability are believed to depend on the accumulation or exhaustion of the sensorial power, as their proximate cause; and on the difference of the present stimulus, and of that which we had previously been accustomed to, as their remote cause. Thus a smaller degree of heat produces pain and inflammation in our hands, after they have been for a time immersed in snow; which is owing to the accumulation of sensorial power in the moving fibres of the cutaneous vessels during their previous quiescence, when they were benumbed with cold. And we feel ourselves cold in the usual temperature of the atmosphere on coming out of a warm room; which is owing to the exhaustion of sensorial power in the moving fibres of the vessels of the skin by their previous increased activity, into which they were excited by unusual heat. Hence the cold fits of fever are the occasion of the succeeding hot ones; and the hot fits contribute to occasion in their turn the succeeding cold ones. And though the increase of stimulus, as of heat, exercise, or distention, will produce an increased action of the stimulated fibres; in the same manner as it is produced by the increased irritability which was occasioned by a previous defect of stimulus; yet as the excesses of irritation from the stimulus of external things are more easily avoided than the deficiencies of it; the diseases of this country, except those which are the consequences of drunkenness, or of immoderate exercise, more frequently begin with torpor than with orgasm; that is, with inactivity of some parts, or of the whole of the system, and consequent coldness, than with increased activity, and consequent heat. If the hot fit be the consequence of the cold one, it may be asked if they are proportionate to each other: it is probable that they are, where no part is destroyed by the cold fit, as in mortification or death. But we have no measure to distinguish this, except the time of their duration; whereas the extent of the torpor over a greater or less part of the system, which occasions the cold fit; or of the exertion which occasions the hot one; as well as the degree of such torpor or exertion, are perhaps more material than the time of their duration. Besides this some muscles are less liable to accumulate sensorial power during their torpor, than others, as the locomotive muscles compared with the capillary arteries; on all which accounts a long cold fit may often be followed by a short hot one. SPECIES. 1. _Febris irritativa._ Irritative fever. This is the synocha of some writers, it is attended with strong pulse without inflammation; and in this circumstance differs from the febris inirritativa of Class I. 2. 1. 1. which is attended with weak pulse without inflammation. The increased frequency of the pulsation of the heart and arteries constitutes fever; during the cold fit these pulsations are always weak, as the energy of action is then decreased throughout the whole system; and therefore the general arterial strength cannot be determined by the touch, till the cold part of the paroxysm ceases. This determination is sometimes attended with difficulty; as strong and weak are only comparative degrees of the greater or less resistance of the pulsation of the artery to the compression of the finger. But the greater or less frequency of the pulsations affords a collateral evidence in those cases, where the degree of strength is not very distinguishable, which may assist our judgment concerning it. Since a moderately strong pulse, when the patient is in a recumbent posture, and not hurried in mind, seldom exceeds 120 strokes in a minute; whereas a weak one often exceeds 130 in a recumbent posture, and 150 in an erect one, in those fevers, which are termed nervous or putrid. See Sect. XII. 1. 4. The increased frequency of the pulsation of the heart and arteries, as it is occasioned either by excess or defect of stimulus, or of sensorial power, exists both in the cold and hot fits of fever; but when the cold fit ceases, and the pulse becomes strong and full as well as quick, in consequence of the increased irritability of the heart and arteries, it constitutes the irritative fever, or synocha. It is attended with considerable heat during the paroxysm, and generally terminates in a quarter of a lunation, without any disturbance of the faculties of the mind. See Class IV. 1. 1. 8. M. M. Venesection. Emetics. Cathartics. Cool the patient in the hot fit, and warm him in the cold one. Rest. Torpentia. 2. _Ebrietas._ Drunkenness. By the stimulus of wine or opium the whole arterial system, as well as every other part of the moving system, is excited into increased action. All the secretions, and with them the production of sensorial power itself in the brain, seem to be for a time increased, with an additional quantity of heat, and of pleasureable sensation. See Sect. XXI. on this subject. This explains, why at the commencement of the warm paroxysm of some fevers the patient is in greater spirits, or vivacity; because, as in drunkenness, the irritative motions are all increased, and a greater production of sensation is the consequence, which when in a certain degree, is pleasureable, as in the diurnal fever of weak people. Sect. XXXVI. 3. 1. 3. _Hæmorrhagia arteriosa._ Arterial hæmorrhage. Bleeding with a quick, strong, and full pulse. The hæmorrhages from the lungs, and from the nose, are the most frequent of these; but it sometimes happens, that a small artery but half divided, or the puncture of a leech, will continue to bleed pertinaciously. M. M. Venesection. Cathartic with calomel. Divide the wounded artery. Bind sponge on the puncture. If coffee or charcoal internally? If air with less oxygen? 4. _Hæmoptoe arteriosa._ Spitting of arterial blood. Blood spit up from the lungs is florid, because it has just been exposed to the influence of the air in its passage through the extremities of the pulmonary artery; it is frothy, from the admixture of air with it in the bronchia. The patients frequently vomit at the same time from the disagreeable titillation of blood about the fauces; and are thence liable to believe, that the blood is rejected from the stomach. Sometimes an hæmoptoe for several successive days returns in gouty persons without danger, and seems to supply the place of the gouty paroxysms. Is not the liver always diseased previous to the hæmoptoe, as in several other hæmorrhages? See Class I. 2. 1. 9. M. M. Venesection, a purge, a blister, diluents, torpentia; and afterwards sorbentia, as the bark, the acid of vitriol, and opium. An emetic is said to stop a pulmonary hæmorrhage, which it may effect, as sickness decreases the circulation, as is very evident in the great sickness sometimes produced by too large a dose of digitalis purpurea. Dr. Rush says, a table spoonful or two of common salt is successful in hæmoptoe; this may be owing to its stimulating the absorbent systems, both the lymphatic, and the venous. Should the patient respire air with less oxygen? or be made sick by whirling round in a chair suspended by a rope? One immersion in cold water, or a sudden sprinkling all over with cold water, would probably stop a pulmonary hæmorrhage. See Sect. XXVII. 1. 5. _Hæmorrhagia narium._ _Epistaxis_. Bleeding at the nose in elderly subjects most frequently attends those, whose livers are enlarged or inflamed by the too frequent use of fermented liquors. In boys it occurs perhaps simply from redundancy of blood; and in young girls sometimes precedes the approach of the catamenia; and then it shews a disposition contrary to chlorosis; which arises from a deficiency of red blood. M. M. It is stopped by plunging the head into cold water, with powdered salt hastily dissolved in it; or sometimes by lint strewed over with wheat flour put up the nostrils; or by a solution of steel in brandy applied to the vessel by means of lint. The cure in other respects as in hæmoptoe; when the bleeding recurs at certain periods, after venesection, and evacuation by calomel, and a blister, the bark and steel must be given, as in intermittent fevers. See Section XXVII. 1. * * * * * ORDO I. _Increased Irritation._ GENUS II. _With increased Actions of the Secerning System._ These are always attended with increase of partial or of general heat; for the secreted fluids are not simply separated from the blood, but are new combinations; as they did not previously exist as such in the blood vessels. But all new combinations give out heat chemically; hence the origin of animal heat, which is always increased in proportion to the secretion of the part affected, or to the general quantity of the secretions. Nevertheless there is reason to believe, that as we have a sense purposely to distinguish the presence of greater or less quantities of heat, as mentioned in Sect. XIV. 6. so we may have certain minute glands for the secretion of this fluid, as the brain is believed to secrete the sensorial power, which would more easily account for the instantaneous production of the blush of shame, and of anger. This subject deserves further investigation. SPECIES. 1. _Calor febrilis._ The heat in fevers arises from the increase of some secretion, either of the natural fluids, as in irritative fevers; or of new fluids, as in infectious fevers; or of new vessels, as in inflammatory fevers. The pain of heat is a consequence of the increased extension or contraction of the fibres exposed to so great a stimulus. See CLASS I. 1. 5. 6. 2. _Rubor febrilis._ Febrile redness. When the cold fit of fever terminates, and the pulsations of the heart and arteries become strong as well as quick from the increase of their irritability after their late quiescence, the blood is impelled forwards into the fine extremities of the arteries, and the anastomozing capillaries, quicker than the extremities of the veins can absorb and return it to the heart. Hence the pulse at the wrist becomes full, as well as quick and strong, and the skin glows with arterial blood, and the veins become empty and less visible. In elderly people the force of the heart and arteries becomes less, while the absorbent power of the veins remains the same; whence the capillary vessels part with the blood, as soon as it is received, and the skin in consequence becomes paler; it is also probable, that in more advanced life some of the finer branches of the arteries coalesce, and become impervious, and thus add to the opacity of the skin. 3. _Sudor calidus._ Warm sweat may be divided into four varieties, according to their remote causes. _First_, the perspirable matter is secreted in as great quantity during the hot fit of fever, as towards the end of it, when the sweat is seen upon the skin. But during the hot fit the cutaneous absorbents act also with increased energy, and the exhalation is likewise increased by the greater heat of the skin; and hence it does not appear in drops on the surface, but is in part reabsorbed, and in part dissipated in the atmosphere. But as the mouths of the cutaneous absorbents are exposed to the cool air or bedclothes; whilst those of the capillary glands, which secrete the perspirable matter, are exposed to the warmth of the circulating blood; the former, as soon as the fever-fit begins to decline, lose their increased action first; and hence the absorption of the sweat is diminished, whilst the increased secretion of it continues for some hours afterwards, which occasions it to stand in drops upon the skin. As the skin becomes cooler, the evaporation of the perspirable matter becomes less, as well as the absorption of it. And hence the dissipation of aqueous fluid from the body, and the consequent thirst, are perhaps greater during the hot fit, than during the subsequent sweat. For the sweats do not occur, according to Dr. Alexander's experiments, till the skin is cooled from 112 to 108 degrees of heat; that is, till the paroxysm begins to decline. From this it appears, that the sweats are not critical to the hot fit, any more than the hot fit can be called critical to the cold one; but simply, that they are the natural consequence of the decline of the hot fit, commencing with the decreased action of the absorbent system, and the decreased evaporation from the skin. And from hence it may be concluded, that a fever-fit is not in general an effort of nature to restore health, as Sydenham considered it, but a necessary consequence of the previous torpor; and that the causes of fevers would be less detrimental, if the fever itself could be prevented from existing; as appears in the cool treatment of the small-pox. It must be noted that the profuse sweats on the skin are more frequent at the decline of fever-fits than the copious urine, or loose stools, which are mentioned below; as the cutaneous absorbents, being exposed to the cool air, lose their increased action sooner than the urinary or intestinal absorbents; which open into the warm cavities of the bladder and intestines; but which are nevertheless often affected by their sympathy with the cutaneous absorbents. Hence few fevers terminate without a moisture of the skin; whence arose the fatal practice of forcing sweats by the external warmth of air or bedclothes in fevers; for external warmth increases the action of the cutaneous capillaries more than that of the other secerning vessels; because the latter are habituated to 98 degrees of heat, the internal warmth of the body; whereas the cutaneous capillaries being nearer the surface are habitually kept cooler by the contact of the external air. Sweats thus produced by heat in confined rooms are still more detrimental; as the air becomes then not only deprived of a part of its oxygene by frequent respiration, but is loaded with animal effluvia as well as with moisture, till it can receive no more; and in consequence, while the cutaneous secretion stands upon the skin in drops for want of exhalation, the lungs are exposed to an insalubrious atmosphere. I do not deny, that sweating may be so managed as to be serviceable in preventing the return of the cold paroxysm of fevers; like the warm bath, or any other permanent stimulus, as wine, or opium, or the bark. For this purpose it should be continued till past the time of the expected cold fit, supported by moderate doses of wine-whey, with spirit of hartshorn, and moderate degrees of warmth. Its salutary effect, when thus managed, was probably one cause of its having been so much attended to; and the fetid smell, which when profuse is liable to accompany it, gave occasion to the belief, that the supposed material cause of the disease was thus eliminated from the circulation. When too great external heat is applied, the system is weakened by excess of action, and the torpor which causes the cold paroxysm recurs sooner and more violently. For though some stimuli, as of opium and alcohol, at the same time that they exhaust the sensorial power by promoting increase of fibrous action, may also increase the production or secretion of it in the brain, yet experience teaches us, that the exhaustion far out-balances the increased production, as is evinced by the general debility, which succeeds intoxication. In respect to the fetor attending copious continued sweats, it is owing to the animalized part of this fluid being kept in that degree of warmth, which most favours putrefaction, and not suffered to exhale into the atmosphere. Broth, or other animal mucus, kept in similar circumstances, would in the same time acquire a putrid smell; yet has this error frequently produced miliary eruptions, and increased every kind of inflammatory or sensitive fever. The ease, which the patient experiences during sweating, if it be not produced by much external heat, is similar to that of the warm bath; which by its stimulus applied to the cutaneous vessels, which are generally cooler than the internal parts of the system, excites them into greater action; and pleasureable sensation is the consequence of these increased actions of the vessels of the skin. From considering all these circumstances, it appears that it is not the evacuation by sweats, but the continued stimulus, which causes and supports those sweats, which is serviceable in preventing the returns of fever-fits. And that sweats too long continued, or induced by too great stimulus of warmth, clothes, or medicines, greatly injure the patient by increasing inflammation, or by exhausting the sensorial power. See Class I. 1. 2. 14. _Secondly_, The sweats produced by exercise or labour are of the warm kind; as they originate from the increased action of the capillaries of the skin, owing to their being more powerfully stimulated by the greater velocity of the blood, and by a greater quantity of it passing through them in a given time. For the blood during violent exercise is carried forwards by the action of the muscles faster in the arteries, than it can be taken up by the veins; as appears by the redness of the skin. And from the consequent sweats, it is evinced, that the secretory vessels of the skin during exercise pour out the perspirable matter faster, than the mouths of the absorbent vessels can drink it up. Which mouths are not exposed to the increased muscular action, or to the stimulus of the increased velocity and quantity of the blood, but to the cool air. _Thirdly_, the increased secretion of perspirable matter occasioned by the stimulus of external heat belongs likewise to this place; as it is caused by the increased motions of the capillary vessels; which thus separate from the blood more perspirable matter, than the mouths of their correspondent absorbent vessels can take up; though these also are stimulated by external heat into more energetic action. If the air be stationary, as in a small room, or bed with closed curtains, the sweat stands in drops on the skin for want of a quicker exhalation proportioned to the quicker secretion. A _fourth_ variety of warm perspiration is that occasioned by stimulating drugs, of which opium and alcohol are the most powerful; and next to these the spices, volatile alkali, and neutral salts, especially sea salt; that much of the aqueous part of the blood is dissipated by the use of these drugs, is evinced by the great thirst, which occurs a few hours after the use of them. See Art. III. 2. 12. and Art. III. 2. 1. We may from hence understand, that the increase of this secretion of perspirable matter by artificial means, must be followed by debility and emaciation. When this is done by taking much salt, or salted meat, the sea-scurvy is produced; which consists in the inirritability of the bibulous terminations of the veins arising from the capillaries; see Class I. 2. 1. 14. The scrophula, or inirritability of the lymphatic glands, seems also to be occasionally induced by an excess in eating salt added to food of bad nourishment. See Class I. 2. 3. 21. If an excess of perspiration is induced by warm or stimulant clothing, as by wearing flannel in contact with the skin in the summer months, a perpetual febricula is excited, both by the preventing the access of cool air to the skin, and by perpetually goading it by the numerous and hard points of the ends of the wool; which when applied to the tender skins of young children, frequently produce the red gum, as it is called; and in grown people, either an erysipelas, or a miliary eruption, attended with fever. See Class II. 1. 3. 12. Shirts made of cotton or calico stimulate the skin too much by the points of the fibres, though less than flannel; whence cotton handkerchiefs make the nose sore by frequent use. The fibres of cotton are, I suppose, ten times shorter than those of flax, and the number of points in consequence twenty times the number; and though the manufacturers singe their calicoes on a red-hot iron cylinder, yet I have more than once seen an erysipelas induced or increased by the stimulus of calico, as well as of flannel. The increase of perspiration by heat either of clothes, or of fire, contributes much to emaciate the body; as is well known to jockeys, who, when they are a stone or two too heavy for riding, find the quickest way to lessen their weight is by sweating themselves between blankets in a warm room; but this likewise is a practice by no means to be recommended, as it weakens the system by the excess of so general a stimulus, brings on a premature old age, and shortens the span of life; as may be further deduced from the quick maturity, and shortness of the lives, of the inhabitants of Hindostan, and other tropical climates. M. Buffon made a curious experiment to shew this circumstance. He took a numerous brood of the butterflies of silkworms, some hundreds of which left their eggs on the same day and hour; these he divided into two parcels; and placing one parcel in the south window, and the other in the north window of his house, he observed, that those in the colder situation lived many days longer than those in the warmer one. From these observations it appears, that the wearing of flannel clothing next the skin, which is now so much in fashion, however useful it may be in the winter to those, who have cold extremities, bad digestions, or habitual coughs, must greatly debilitate them, if worn in the warm months, producing fevers, eruptions, and premature old age. See Sect. XXXVII. 5. Class I. 1. 2. 14. Art. III. 2. 1. 4. _Urina uberior colorata._ Copious coloured urine. Towards the end of fever-fits a large quantity of high coloured urine is voided, the kidneys continuing to act strongly, after the increased action of the absorbents of the bladder is somewhat diminished. If the absorbents continue also to act strongly, the urine is higher coloured, and so loaded as to deposit, when cool, an earthy sediment, erroneously thought to be the material cause of the disease; but is simply owing to the secretion of the kidnies being great from their increased action; and the thinner parts of it being absorbed by the increased action of the lymphatics, which are spread very thick on the neck of the bladder; for the urine, as well as perhaps all the other secreted fluids, is produced from the kidnies in a very dilute state; as appears in those, who from the stimulus of a stone, or other cause, evacuate their urine too frequently; which is then pale from its not having remained in the bladder long enough for the more aqueous part to have been reabsorbed. The general use of this urinary absorption to the animal oeconomy is evinced from the urinary bladders of fish, which would otherwise be unnecessary. High coloured urine in large quantity shews only, that the secreting vessels of the kidnies, and the absorbents of the bladder, have acted with greater energy. When there is much earthy sediment, it shews, that the absorbents have acted proportionally stronger, and have consequently left the urine in a less dilute state. In this urine the transparent sediment or cloud is mucous; the opake sediment is probably coagulable lymph from the blood changed by an animal or chemical process. The floating scum is oil. The angular concretions to the sides of the pot, formed as the urine cools, is microcosmic salt. Does the adhesive blue matter on the sides of the glass, or the blue circle on it at the edge of the upper surface of the urine, consist of Prussian blue? 5. _Diarrhoea calida._ Warm diarrhoea. This species may be divided into three varieties deduced from their remote causes, under the names of diarrhoea febrilis, diarrhoea crapulosa, and diarrhoea infantum. The febrile diarrhoea appears at the end of fever-fits, and is erroneously called critical, like the copious urine, and the sweats; whereas it arises from the increased action of those secerning organs, which pour their fluids into the intestinal canal (as the liver, pancreas, and mucous glands), continuing longer than the increased action of the intestinal absorbents. In this diarrhoea there is no appearance of curdled chyle in the stools, as occurs in cholera. I. 3. 1. 5. The _diarrhoea crapulosa_, or diarrhoea from indigestion, occurs when too great a quantity of food or liquid has been taken; which not being compleatly digested, stimulates the intestines like any other extraneous acrid material; and thus produces an increase of the secretions into them of mucus, pancreatic juice, and bile. When the contents of the bowels are still more stimulant, as when drastic purges, or very putrescent diet, have been taken, a cholera is induced. See Sect. XXIX. 4. The _diarrhoea infantum_, or diarrhoea of infants, is generally owing to too great acidity in their bowels. Milk is found curdled in the stomachs of all animals, old as well as young, and even of carnivorous ones, as of hawks. (Spallanzani.) And it is the gastric juice of the calf, which is employed to curdle milk in the process of making cheese. Milk is the natural food for children, and must curdle in their stomachs previous to digestion; and as this curdling of the milk destroys a part of the acid juices of the stomach, there is no reason for discontinuing the use of it, though it is occasionally ejected in a curdled state. A child of a week old, which had been taken from the breast of its dying mother, and had by some uncommon error been suffered to take no food but water-gruel, became sick and griped in twenty-four hours, and was convulsed on the second day, and died on the third! When all young quadrupeds, as well as children, have this natural food of milk prepared for them, the analogy is so strong in favour of its salubrity, that a person should have powerful testimony indeed of its disagreeing, before he advises the discontinuance of the use of it to young children in health, and much more so in sickness. The farmers lose many of their calves, which are brought up by gruel, or gruel and old milk; and among the poor children of Derby, who are thus fed, hundreds are starved into the scrophula, and either perish, or live in a state of wretched debility. When young children are brought up without a breast, they should for the first two months have no food but new milk; since the addition of any kind of bread or flour is liable to ferment, and produce too much acidity; as appears by the consequent diarrhoea with green dejections and gripes; the colour is owing to a mixture of acid with the natural quantity of bile, and the pain to its stimulus. And they should never be fed as they lie upon their backs, as in that posture they are necessitated to swallow all that is put into their mouths; but when they are fed, as they are sitting up, or raised up, when they have had enough, they can permit the rest to run out of their mouths. This circumstance is of great importance to the health of those children, who are reared by the spoon, since if too much food is given them, indigestion, and gripes, and diarrhoea, is the consequence; and if too little, they become emaciated; and of this exact quantity their own palates judge the best. M. M. In this last case of the diarrhoea of children, the food should be new milk, which by curdling destroys part of the acid, which coagulates it. Chalk about four grains every six hours, with one drop of spirit of hartshorn, and half a drop of laudanum. But a blister about the size of a shilling is of the greatest service by restoring the power of digestion. See Article III. 2. 1. in the subsequent Materia Medica. 6. _Salivatio calida._ Warm salivation. Increased secretion of saliva. This may be effected either by stimulating the mouth of the gland by mercury taken internally; or by stimulating the excretory duct of the gland by pyrethrum, or tobacco; or simply by the movement of the muscles, which lie over the gland, as in masticating any tasteless substance, as a lock of wool, or mastic. In about the middle of nervous fevers a great spitting of saliva sometimes occurs, which has been thought critical; but as it continues sometimes two or even three weeks without the relief of the patient, it may be concluded to arise from some accidental circumstance, perhaps not unsimilar to the hysteric ptyalisms mentioned in Class I. 3. 2. 2. See Sect. XXIV. M. M. Cool air, diluents, warm bath, evacuations. 7. _Catharrhus calidus._ Warm catarrh. Consists in an increased secretion of mucus from the nostrils without inflammation. This disease, which is called a cold in the head, is frequently produced by cold air acting for some time on the membranes, which line the nostrils, as it passes to the lungs in respiration. Whence a torpor of the action of the mucous glands is first introduced, as in I. 2. 3. 3. and an orgasm or increased action succeeds in consequence. Afterwards this orgasm and torpor are liable to alternate with each other for some time like the cold and hot fits of ague, attended with deficient or exuberant secretion of mucus in the nostrils. At other times it arises from reverse sympathy with some extensive parts of the skin, which have been exposed too long to cold, as of the head, or feet. In consequence of the torpor of these cutaneous capillaries those of the mucous membrane of the nostrils act with greater energy by reverse sympathy; and thence secrete more mucus from the blood. At the same time the absorbents, acting also with greater energy by their reverse sympathy with those of some distant part of the skin, absorb the thinner parts of the mucus more hastily; whence the mucus is both thicker and in greater quantity. Other curious circumstances attend this disease; the membrane becomes at times so thickened by its increased action in secreting the mucus, that the patient cannot breathe through his nostrils. In this situation if he warms his whole skin suddenly by fire or bed-clothes, or by drinking warm tea, the increased action of the membrane ceases by its reverse sympathy with the skin; or by the retraction of the sensorial power to other parts of the system; and the patient can breathe again through the nostrils. The same sometimes occurs for a time on going into the cold air by the deduction of heat from the mucous membrane, and its consequent inactivity or torpor. Similar to this when the face and breast have been very hot and red, previous to the eruption of the small-pox by inoculation, and that even when exposed to cool air, I have observed the feet have been cold; till on covering them with warm flannel, as the feet have become warm, the face has cooled. See Sect. XXXV. 1. 3. Class II. 1. 3. 5. IV. 2. 2. 10. IV. 1. 1. 5. M. M. Evacuations, abstinence, oil externally on the nose, warm diluent fluids, warm shoes, warm night-cap. 8. _Expectoratio calida._ Warm expectoration consists of the increased secretion of mucus from the membrane, which lines the bronchiæ, or air-cells of the lungs, without inflammation. This increased mucus is ejected by the action of coughing, and is called a cold, and resembles the catarrh of the preceding article; with which it is frequently combined. M. M. Inhale the steam of warm water, evacuations, warm bath, afterwards opium, sorbentia. 9. _Exsudatio pone aures._ A discharge behind the ears. This chiefly affects children, and is a morbid secretion; as appears from its fetor; for if it was owing to defect of absorption, it would be saline, and not fetid; if a morbid action has continued a considerable time, it should not be stopped too suddenly; since in that case some other morbid action is liable to succeed in its stead. Thus children are believed to have had cholics, or even convulsions, consequent to the too sudden healing of these morbid effusions behind their ears. The rationale of this is to be explained from a medical fact, which I have frequently observed; and that is, that a blister on the back greatly strengthens the power of digestion, and removes the heart-burn in adults, and green stools in children. The stimulus of the blister produces sensation in the vessels of the skin; with this additional sensorial power these vessels act more strongly; and with these the vessels of the internal membranes of the stomach and bowels act with greater energy from their direct sympathy with them. Now the acrid discharge behind the ears of children produces sensation on that part of the skin, and so far acts as a small blister. When this is suddenly stopped, a debility of the digestive power of the stomach succeeds from the want of this accustomed stimulus, with flatulency, green stools, gripes, and sometimes consequent convulsions. See Class II. 1. 5. 6. and II. 1. 4. 6. M. M. If the matter be absorbed, and produces swelling of the lymphatics of the neck, it should be cured as soon as possible by dusting the part with white lead, cerussa, in very fine powder; and to prevent any ill consequence an issue should be kept for about a month in the arm; or a purgative medicine should be taken, every other day for three or four times, which should consist of a grain of calomel, and three or four grains of rhubarb, and as much chalk. If there be no appearance of absorption, it is better only to keep the parts clean by washing them with warm water morning and evening; or putting fuller's earth on them; especially till the time of toothing is past. The tinea, or scald head, and a leprous eruption, which often appears behind the ears, are different diseases. 10. _Gonorrhea calida._ Warm gleet. Increased discharge of mucus from the urethra or prostrate gland without venereal desire, or venereal infection. See Class I. 2. 3. 8. M. M. Cantharides, balsams, rhubarb, blister in perinæum, cold bath, injections of metallic salts, flannel shirt, change of the form of the accustomed chair or saddle of the patient. 11. _Fluor albus calidus._ Warm fluor albus. Increased secretion of mucus in the vagina or uterus without venereal desire or venereal infection. It is distinguished from the fluor albus frigidus by the increased sense of warmth in the part, and by the greater opacity or spissitude of the material discharged; as the thinner parts are reabsorbed by the increased action of the absorbents, along with the saline part, whence no smarting or excoriation attends it. M. M. Mucilage, as isinglass, hartshorn jelly, gum arabic. Ten grains of rhubarb every night. Callico or flannel shift, opium, balsams. See Class I. 2. 3. 7. 12. _Hæmorrhois alba._ White piles. An increased discharge of mucus from the rectum frequently mistaken for matter; is said to continue a few weeks, and recur like the bleeding piles; and to obey lunar influence. See Class I. 2. 1. 6. M. M. Abstinence from vinous spirit. Balsam of copaiva. Spice swallowed in large fragments, as ten or fifteen black pepper-corns cut in half, and taken after dinner and supper. Ward's paste, consisting of black pepper and the powdered root of Helenium Enula. 13. _Serum e vesicatorio._ Discharge from a blister. The excretory ducts of glands terminate in membranes, and are endued with great irritability, and many of them with sensibility; the latter perhaps in consequence of their facility of being excitable into great action; instances of this are the terminations of the gall-duct in the duodenum, and of the salivary and lachrymal glands in the mouth and eye; which produce a greater secretion of their adapted fluids, when the ends of their excretory ducts are stimulated. The external skin consists of the excretory ducts of the capillaries, with the mouths of the absorbents; when these are stimulated by the application of cantharides, or by a slice of the fresh root of bryonia alba bound on it, the capillary glands pour an increased quantity of fluid upon the skin by their increased action; and the absorbent vessels imbibe a greater quantity of the more fluid and saline part of it; whence a thick mucous or serous fluid is deposited between the skin and cuticle. 14. _Perspiratio foetida._ Fetid perspiration. The uses of the perspirable matter are to keep the skin soft and pliant, for the purposes of its easier flexibility during the activity of our limbs in locomotion, and for the preservation of the accuracy of the sense of touch, which is diffused under the whole surface of it to guard us against the injuries of external bodies; in the same manner as the secretion of tears is designed to preserve the cornea of the eye moist, and in consequence transparent; yet has this cutaneous mucus been believed by many to be an excrement; and I know not how many fanciful theories have been built on its supposed obstruction. Such as the origin of catarrhs, coughs, inflammations, erysypelas, and herpes. To all these it may be sufficient to answer, that the antient Grecians oiled themselves all over; that some nations have painted themselves all over, as the Picts of this island; that the Hottentots smear themselves all over with grease. And lastly, that many of our own heads at this day are covered with the flour of wheat and the fat of hogs, according to the tyranny of a filthy and wasteful fashion, and all this without inconvenience. To this must be added the strict analogy between the use of the perspirable matter and the mucous fluids, which are poured for similar purposes upon all the internal membranes of the body; and besides its being in its natural state inodorous; which is not so with the other excretions of feces, or of urine. In some constitutions the perspirable matter of the lungs acquires a disagreeable odour; in others the axilla, and in others the feet, emit disgustful effluvia; like the secretions of those glands, which have been called odoriferæ; as those, which contain the castor in the beaver, and those within the rectum of dogs, the mucus of which has been supposed to guard them against the great costiveness, which they are liable to in hot summers; and which has been thought to occasion canine madness, but which, like their white excrement, is more probably owing to the deficient secretion of bile. Whether these odoriferous particles attend the perspirable matter in consequence of the increased action of the capillary glands, and can properly be called excrementitous; that is, whether any thing is eliminated, which could be hurtful if retained; or whether they may only contain some of the essential oil of the animal; like the smell, which adheres to one's hand on stroking the hides of some dogs; or like the effluvia, which is left upon the ground, from the feet of men and other creatures; and is perceptible by the nicer organs of the dogs, which hunt them, may admit of doubt. M. M. Wash the parts twice a day with soap and water; with lime water; cover the feet with oiled silk socks, which must be washed night and morning. Cover them with charcoal recently made red hot, and beaten into fine powder and sifted, as soon as cold, and kept well corked in a bottle, to be warned off and renewed twice a day. Internally rhubarb grains vi. or viii. every night, so as to procure a stool or two extraordinary every day, and thus by increasing one evacuation to decrease another. Cool dress, diluting liquids? 15. _Crines novi._ New hairs. The black points on the faces of some people consist of mucus, which is become viscid, and which adheres in the excretory ducts of the glands of the skin; as described in Class I. 2. 2. 9. and which may be pressed out by the fingers, and resembles little worms. Similar to this would seem the fabrication of silk, and of cobweb by the silk worm and spider; which is a secreted matter pressed through holes, which are the excretory ducts of glands. And it is probable, that the production of hair on many parts of the body, and at different periods of life, may be effected by a similar process; and more especially as every hair may be considered as a slender flexible horn, and is an appendage of the skin. See Sect. XXXIX. 3. 2. Now as there is a sensitive sympathy between the glands, which secrete the semen, and the throat, as appears in the mumps; see Hydrophobia, Class IV. 1. 2. 7. and Parotitis, Class IV. 1. 2. 19. The growth of the beard at puberty seems to be caused by the greater action of the cutaneous glands about the chin and pubes in consequence of their sympathy with those of the testes. But this does not occur to the female sex at their time of puberty, because the sensitive sympathy in them seems to exist between the submaxillary glands, and the pectoral ones; which secrete the milk, and afford pleasure both by that secretion, and by the erection of the mamulæ, or nipples; and by delivering the milk into the mouth of the child; this sensitive sympathy of the pectoral and submaxillary glands in women is also observable in the Parotitis, or mumps, as above referred to. When hairs grow on the face or arms so as to be disagreeable, they may be thus readily removed without pain or any ill consequence. Warm the ends of a pair of nippers or forceps, and stick on them a little rosin, or burgundy pitch; by these means each single hair may be taken fast hold of; and if it be then plucked off slowly, it gives pain; but if plucked off suddenly, it gives no pain at all; because the vis inertiæ of the part of the skin, to which it adheres, is not overcome; and it is not in consequence separated from the cellular membrane under it. Some of the hairs may return, which are thus plucked off, or others may be induced to grow near them; but in a little time they may be thus safely destroyed; which is much to be preferred to the methods said to be used in Turkey to eradicate hair; such as a mixture of orpiment and quick lime; or of liver of sulphur in solution; which injure the skin, if they are not very nicely managed; and the hair is liable to grow again as after shaving; or to become white, if the roots of it have been much inflamed by the causticity of the application. See Class I. 2. 2. 11. on grey hairs. * * * * * ORDO I. _Increased Irritation._ GENUS III. _With increased Actions of the Absorbent System._ These are not attended with so great increase of heat as in the former genus, because the fluids probably undergo less chemical change in the glands of the absorbent system; nor are the glands of the absorbent vessels so numerous or so extensive as those of the secerning ones. Yet that some heat is produced by the increased action of the absorbents appears from the greater general warmth of the skin and extremities of feeble patients after the exhibition of the peruvian bark, and other medicines of the article Sorbentia. SPECIES. 1. _Lingua arida._ Dry tongue occurs in those fevers, where the expired air is warmer than natural; and happens to all those, who sleep with their mouths open; the currents of air in respiration increasing the evaporation. There is also a dryness in the mouth from the increased action of the absorbent vessels, when a sloe or a crab-apple are masticated; and after the perforation has been much increased by eating salt or spice, or after other copious secretions; as after drunkenness, cathartics, or fever fits, the mucus of the mouth becomes viscid, and in small quantity, from the increased absorption, adhering to the tongue like a white slough. In the diabætes, where the thirst is very great, this slough adheres more pertinaciously, and becomes black or brown, being coloured after a few days by our aliment or drink. The inspissated mucus on the tongue of those, who sleep with their mouths open, is sometimes reddened as if mixed with blood, and sometimes a little blood follows the expuition of it from the fauces owing to its great adhesion. When this mucus adheres long to the papillæ of the tongue, the saliva, which it contains in its interstices, like a sponge, is liable to become putrid, and to acquire a bitter taste, like other putrid animal substances; which is generally mistaken for an indication of the presence of bile. M. M. Warm subacid liquids. See Class I. 2. 5. 8. 2. _Fauces aridæ._ Dry throat. The expuition of a frothy mucus with great and perpetual hawking occurs in hydrophobia, and is very distressing to the patient; which may be owing to the increased irritability or sensibility of the upper part of the oesophagus, which will not permit any fluid to rest on it. It affects some people after intoxication, when the lungs remain slightly inflamed, and by the greater heat of the air in expiration the mucus becomes too hastily evaporated, and is expectorated with difficulty in the state of white froth. I knew a person, who for twenty years always waked with his tongue and throat quite dry; so that he was necessitated to take a spoonful of water, as soon as he awoke; otherwise a little blood always followed the forcible expuition of the indurated mucus from his fauces. See Class II. 1. 3. 17. M. M. Steel-springs fixed to the night-cap so as to suspend the lower jaw and keep it closed; or springs of elastic gum. Or a pot of water suspended over the bed, with a piece of list, or woollen cloth, depending from it, and held in the mouth; which will act like a syphon, and slowly supply moisture, or barley water should be frequently syringed into the mouth of the patient. 3. _Nares aridi._ Dry nostrils with the mucus hardening upon their internal surface, so as to cover them with a kind of skin or scale, owing to the increased action of the absorbents of this membrane; or to the too great dryness of the air, which passes into the lungs; or too great heat of it in its expiration. When air is so dry as to lose its transparency; as when a tremulous motion of it can be seen over corn fields in a hot summer's day; or when a dry mist, or want of transparency of the air, is visible in very hot weather; the sense of smell is at the same time imperfect from the dryness of the membrane, beneath which it is spread. 4. _Expectoratio solida._ Solid expectoration. The mucus of the lungs becomes hardened by the increased absorption, so that it adheres and forms a kind of lining in the air-cells, and is sometimes spit up in the form of branching vessels, which are called polypi of the lungs. See Transact. of the College, London. There is a rattling or weezing of the breath, but it is not at first attended with inflammation. The Cynanche trachealis, or Croup, of Dr. Cullen, or Angina polyposa of Michaelis, if they differ from the peripneumony of infants, seem to belong to this genus. When the difficulty of respiration is great, venesection is immediately necessary, and then an emetic, and a blister. And the child should be kept nearly upright in bed as much as may be. See Tonsillitis, Class II. 1. 3. 3. M. M. Diluents, emetics, essence of antimony, foetid gums, onions, warm bath for half an hour every day for a month. Inhaling the steam of water, with or without volatile alcali. Soap. 5. _Constipatio alvi._ Costiveness from increased action of the intestinal absorbents. The feces are hardened in lumps called scybala; which are sometimes obliged to be extracted from the rectum with a kind of marrow spoon. This is said to have happened from the patient having taken much rust of iron. The mucus is also hardened so as to line the intestines, and to come away in skins, rolled up as they pass along, so as to resemble worms, for which they are frequently mistaken; and sometimes it is evacuated in still larger pieces, so as to counterfeit the form of the intestines, and has been mistaken for a portion of them. Balls of this kind, nearly as heavy as marble, and considerably hard, from two inches to five in diameter, are frequently found in the bowels of horses. Similar balls found in goats have been called Bezoar. M. M. Cathartics, Diluents, fruit, oil, soap, sulphur, warm bath. Sprinkling with cold water, cool clothing. See Class I. 2. 4. 18. 6. _Cutis arida._ Dry skin. This dry skin is not attended with coldness as in the beginning of fever-fits. Where this cutaneous absorption is great, and the secreted material upon it viscid, as on the hairy scalp, the skin becomes covered with hardened mucus; which adheres so as not to be easily removed, as the scurf on the head; but is not attended with inflammation like the Tinea, or Lepra. The moisture, which appears on the skin beneath resinous or oily plasters, or which is seen to adhere to such plasters, is owing to their preventing the exhalation of the perspirable matter, and not to their increasing the production of it, as some have idly imagined. M. M. Warm bathing, oil externally, oil-skin gloves, resinous plasters. Wax. 7. _Urina parca colorata._ Diminished urine, which is high coloured, and deposits an earthy sediment, when cold, is owing to the great action of the urinary absorbents. See Class I. 1. 2. 4. In some dropsies the cutaneous absorbents are paralytic, as well as those opening into the cellular membrane; and hence, no moisture being acquired from the atmosphere, or from the cellular membrane, great thirst is excited; and great absorption from all parts, where the absorbents are still capable of action. Hence the urine is in very small quantity, and of deep colour, with copious sediment; and the kidneys are erroneously blamed for not doing their office; stimulant diuretic medicines are given in vain; and very frequently the unhappy patient is restrained from quenching his thirst, and dies a martyr to false theory. M. M. Diluent liquids, and warm bathing, are the natural cure of this symptom; but it generally attends those dropsies, which are seldom curable; as they are owing to a paralysis both of the cutaneous and cellular lymphatics. 8. _Calculus felleus._ Gall-stone. From the too hasty absorption of the thinner parts of the bile, the remainder is left too viscid, and crystallizes into lumps; which, if too large to pass, obstruct the ductus choledochus, producing pain at the pit of the stomach, and jaundice. When the indurated bile is not harder than a boiled pea, it may pass through the bile-duct with difficulty by changing its form; and thus gives those pains, which have been called spasms of the stomach; and yet these viscid lumps of bile may afterwards dissolve, and not be visible among the feces. In two instances I have seen from thirty to fifty gall-stones voided after taking an oil vomit as below. They were about the size of peas, and distinguishable when dry by their being inflammable like bad wax, when put into the flame of a candle. For other causes of jaundice, see Class I. 2. 4. 19. M. M. Diluents, daily warm bathing. Ether mixed with yolk of egg and water. Unboiled acrid vegetables, as lettice, cabbage, mustard, and cresses. When in violent pain, four ounces of oil of olives, or of almonds, should be swallowed; and as much more in a quarter of an hour, whether it stays or not. The patient should lie on the circumference of a large barrel, first on one side, and then on the other. Electric shocks through the gall-duct. Factitious Selter's water made by dissolving one dram of Sal Soda in a pint of water; to half a pint of which made luke-warm add ten drops of marine acid; to be drank as soon as mixed, twice a day for some months. Opium must be used to quiet the pain, if the oil does not succeed, as two grains, and another grain in half an hour if necessary. See Class IV. 2. 2. 4. 9. _Calculus renis._ Stone of the kidney. The pain in the loins and along the course of the ureter from a stone is attended with retraction of the testicle in men, and numbness on the inside of the thigh in women. It is distinguished from the lumbago or sciatica, as these latter are seldom attended with vomiting, and have pain on the outside of the thigh, sometimes quite down to the ankle or heel. See Herpes and Nephritis. Where the absorption of the thinner parts of the secretion takes place too hastily in the kidnies, the hardened mucus, and consequent calculous concretions, sometimes totally stop up the tubuli uriniferi; and no urine is secreted. Of this many die, who have drank much vinous spirit, and some of them recover by voiding a quantity of white mucus, like chalk and water; and others by voiding a great quantity of sand, or small calculi. This hardened mucus frequently becomes the nucleus of a stone in the bladder. The salts of the urine, called microcosmic salt, are often mistaken for gravel, but are distinguishable both by their angles of crystallization, their adhesion to the sides or bottom of the pot, and by their not being formed till the urine cools. Whereas the particles of gravel are generally without angles, and always drop to the bottom of the vessel, immediately as the water is voided. Though the proximate cause of the formation of the calculous concretions of the kidneys, and of chalk-stones in the gout, and of the insoluble concretions of coagulable lymph, which are found on membranes, which have been inflamed in peripneumony, or rheumatism, consists in the too great action of the absorbent vessels of those parts; yet the remote cause in these cases is probably owing to the inflammation of the membranes; which at that time are believed to secrete a material more liable to coagulate or concrete, than they would otherwise produce by increased action alone without the production of new vessels, which constitutes inflammation. As defined in Class II. 1. 2. The fluids secreted from the mucous membranes of animals are of various kinds and consistencies. Hair, silk, scales, horns, fingernails, are owing to natural processes. Gall-stones, stones found in the intestines of horses, scurf of the skin in leprosy, stones of the kidnies and bladder, the callus from the inflamed periosteum, which unites broken bones, the calcareous cement, which repairs the injured shells of snails, the calcareous crust on the eggs of birds, the annually renewed shells of crabs, are all instances of productions from mucous membranes, afterwards indurated by absorption of their thinner parts. All these concretions contain phosphoric acid, mucus, and calcareous earth in different proportions; and are probably so far analogous in respect to their component parts as well as their mode of formation. Some calcareous earth has been discovered after putrefaction in the coagulable lymph of animals. Fordyce's Elements of Practice. A little calcareous earth was detected by Scheel or Bergman in the calculus of the bladder with much phosphoric acid, and a great quantity of phosphoric acid is shewn to exist in oyster-shells by their becoming luminous on exposing them a while to the sun's light after calcination; as in the experiments of Wilson. Botanic Garden, P. 1. Canto 1. l. 182, note. The exchange of which phosphoric acid for carbonic acid, or fixed air, converts shells into limestone, producing mountains of marble, or calcareous strata. Now as the hard lumps of calcareous matter, termed crabs' eyes, which are found in the stomachs of those animals previous to the annual renewal of their shells, are redissolved, probably by their gastric acid, and again deposited for that purpose; may it not be concluded, that the stone of the bladder might be dissolved by the gastric juice of fish of prey, as of crabs, or pike; or of voracious young birds, as young rooks or hawks, or even of calves? Could not these experiments be tried by collecting the gastric juice by putting bits of sponge down the throats of young crows, and retracting them by a string in the manner of Spallanzani? or putting pieces of calculus down the throat of a living crow, or pike, and observing if they become digested? and lastly could not gastric juice, if it should appear to be a solvent, be injected and born in the bladder without injury by means of catheters of elastic resin, or caoutchouc? M. M. Diluents. Cool dress. Frequent change of posture. Frequent horizontal rest in the day. Bathe the loins every morning with a sponge and cold water. Aerated alcaline water internally. Abstinence from all fermented or spirituous liquors. Whatever increases perspiration injures these patients, as it dissipates the aqueous particles, which ought to dilute the urine. When the constitution begins to produce gravel, it may I believe be certainly prevented by a total abstinence from fermented or spirituous liquors; by drinking much aqueous fluids; as toast and water, tea, milk and water, lemonade; and lastly by thin clothing, and sleeping on a hardish bed, that the patient may not lie too long on one side. See Class IV. 2. 2. 2. There is reason to believe, that the daily use of opium contributes to produce gravel in the kidnies by increasing absorption, when they are inflamed; in the same manner as is done by fermented or spirituous liquor. See Class I. 3. 2. 11. When the kidnies are so obstructed with gravel, that no urine passes into the bladder; which is known by the external appearance of the lower part of the abdomen, which, when the bladder is full, seems as if contracted by a cord between the navel and the bladder; and by the tension on the region of the bladder distinguishable by the touch; or by the introduction of the catheter; the following methods of cure are frequently successful. Venesection to six or eight ounces, ten grains of calomel, and an infusion of senna with salts and oil, every three hours, till stools are procured. Then an emetic. After the patient has been thus evacuated, a blister on the loins should be used; and from ten to twenty electric shocks should be passed through the kidnies, as large as can be easily borne, once or twice a day. Along with this method the warm bath should be used for an hour once or twice a day. After repeated evacuations a clyster, consisting of two drams of turpentine dissolved by yolk of egg, and sixty drops of tincture of opium, should be used at night, and repeated, with cathartic medicines interposed, every night, or alternate nights. Aerated solution of alcali should be taken internally, and balsam of copaiva, three or four times a day. Some of these patients recover after having made no water for nine or ten days. If a stone sticks in the ureter with incessant vomiting, ten grains of calomel must be given in small pills as above; and some hours afterwards infusion of senna and salts and oil, if it can be made to stay on the stomach. And after the purge has operated four or five times, an opiate is to be given, if the pain continues, consisting of two grains of opium. If this does not succeed, ten or twenty electric shocks through the kidney should be tried, and the purgative repeated, and afterwards the opiate. The patient should be frequently put into the warm bath for an hour at a time. Eighty or an hundred drops of laudanum given in a glyster, with two drams of turpentine, is to be preferred to the two grains given by the stomach as above, when the pain and vomiting are very urgent. 10. _Calculus vesicæ._ Stone of the bladder. The nucleus, or kernel, of these concretions is always formed in the kidney, as above described; and passing down the ureter into the bladder, is there perpetually increased by the mucus and salts secreted from the arterial system, or by the mucus of the bladder, disposed in concentric strata. The stones found in the bowels of horses are also formed on a nucleus, and consist of concentric spheres; as appears in sawing them through the middle. But as these are formed by the indurated mucus of the intestines alone without the urinary salts, it is probable a difference would be found on their analysis. As the stones of the bladder are of various degrees of hardness, and probably differ from each other in the proportions at least of their component parts; when a patient, who labours under this afflicting disease, voids any small bits of gravel; these should be kept in warm solutions of caustic alcali, or of mild alcali well aerated; and if they dissolve in these solutions, it would afford greater hopes, that that which remains in the bladder, might be affected by these medicines taken by the stomach, or injected into the bladder. To prevent the increase of a stone in the bladder much diluent drink should be taken; as half a pint of water warmed to about eighty degrees, three or four times a day: which will not only prevent the growth of it, by preventing any microcosmic salts from being precipitated from the urine, and by keeping the mucus suspended in it; but will also diminish the stone already formed, by softening, and washing away its surface. To this must be added cool dress, and cool bed-clothes, as directed above in the calculus renis. When the stone is pushed against or into the neck of the bladder, great pain is produced; this may sometimes be relieved by the introduction of a bougie to push the stone back into the fundus of the bladder. Sometimes by change of posture, or by an opiate either taken into the stomach, or by a clyster. A dram of sal soda, or of salt of tartar, dissolved in a pint of water, and well saturated with carbonic acid (fixed air), by means of Dr. Nooth's glass-apparatus, and drank every day, or twice a day, is the most efficacious internal medicine yet discovered, which can be easily taken without any general injury to the constitution. An aerated alcaline water of this kind is sold under the name of factitious Seltzer water, by J. Schweppe, at N^o 8, King's-street, Holborn, London; which I am told is better prepared than can be easily done in the usual glass-vessels, probably by employing a greater pressure in wooden ones. Lythotomy is the last recourse. Will the gastric juice of animals dissolve calculi? Will fermenting vegetable juices, as sweet-wort, or sugar and water in the act of fermentation with yest, dissolve any kind of animal concretions? 11. _Calculus arthriticus._ Gout-stones are formed on inflamed membranes, like those of the kidnies above described, by the too hasty absorption of the thinner and saline parts of the mucus. Similar concretions have been produced in the lungs, and even in the pericardium; and it is probable, that the ossification, as it is called, of the minute arteries, which is said to attend old age, and to precede some mortifications of the extremities, may be a process of this kind. As gout-stones lie near the surface, it is probable, that ether, frequently applied in their early state, might render them so liquid as to permit their reabsorption; which the stimulus of the ether might at the same time encourage. 12. _Rheumatismus chronicus._ Chronic rheumatism. After the acute rheumatism some inspissated mucus, or material similar to chalk-stones of the gout, which was secreted on the inflamed membrane, is probably left, owing to the too hasty absorption of the thinner and saline part of it; and by lying on the fascia, which covers some of the muscles, pains them, when they move and rub against it, like any extraneous material. The pain of the shoulder, which attends inflammations of the upper membrane of the liver, and the pains of the arms, which attend asthma dolorificum, or dropsy of the pericardium, are distinguished from the chronic rheumatism, as in the latter the pain only occurs on moving the affected muscles. M. M. Warm bath, cold bath, bandage of emplastrum de minio put on tight, so as to compress the part. Cover the part with flannel. With oiled silk. Rub it with common oil frequently. With ether. A blister. A warmer climate. Venesection. A grain of calomel and a grain of opium for ten successive nights. The Peruvian bark. 13. _Cicatrix vulnerum._ The scar after wounds. In the healing of ulcers the matter is first thickened by increasing the absorption in them; and then lessened, till all the matter is absorbed, which is brought by the arteries, instead of being deposed in the ulcer. M. M. This is promoted by bandage, by the sorbentia externally, as powder of bark, white lead; solution of sugar of lead. And by the sorbentia internally after evacuations. See Sect. XXXIII. 3. 2. In those ulcers, which are made by the contact of external fire, the violent action of the fibres, which occasions the pain, is liable to continue, after the external heat is withdrawn. This should be relieved by external cold, as of snow, salt and water recently mixed, ether, or spirits of wine suffered to evaporate on the part. The cicatrix of an ulcer generally proceeds from the edges of it; but in large ones frequently from the middle, or commences in several places at the same time; which probably contributes to the unevenness of large scars. 14. _Corneæ obfuscatio._ Opacity of the cornea. There are few people, who have passed the middle of life, who have not at some time suffered some slight scratches or injuries of the cornea, which by not healing with a perfectly smooth surface, occasion some refractions of light, which may be conveniently seen in the following manner: fill a tea-saucer with cream and tea, or with milk, and holding it to your lips, as if going to drink it, the imperfections of the cornea will appear like lines or blotches on the surface of the fluid, with a less white appearance than that surface. Those blemishes of the eye are distinguished from the muscæ volitantes described in Class I. 2. 5. 3. by their being invariably seen at any time, when you look for them. Ulcers may frequently be seen on the cornea after ophthalmy, like little pits or indentations beneath the surface of it: in this case no external application should be used, lest the scar should be left uneven; but the cure should be confined to the internal use of thirty grains of bark twice a day, and from five to ten drops of laudanum at night, with five grains of rhubarb, if necessary. After ulcers of the cornea, which have been large, the inequalities and opacity of the cicatrix obscures the sight; in this case could not a small piece of the cornea be cut out by a kind of trephine about the size of a thick bristle, or a small crow-quill, and would it not heal with a transparent scar? This experiment is worth trying, and might be done by a piece of hollow steel wire with a sharp edge, through which might be introduced a pointed steel screw; the screw to be introduced through the opake cornea to hold it up, and press it against the cutting edge of the hollow wire or cylinder; if the scar should heal without losing its transparency, many blind people might be made to see tolerably well by this slight and not painful operation. An experiment I wish strongly to recommend to some ingenious surgeon or oculist. * * * * * ORDO I. _Increased Irritation._ GENUS IV. _With increased Actions of other Cavities and Membranes._ SPECIES. 1. _Nictitatio irritativa._ Winking of the eyes is performed every minute without our attention, for the purpose of cleaning and moistening the eye-ball; as further spoken of in Class II. 1. 1. 8. When the cornea becomes too dry, it becomes at the same time less transparent; which is owing to the pores of it being then too large, so that the particles of light are refracted by the edges of each pore, instead of passing through it; in the same manner as light is refracted by passing near the edge of a knife. When these pores are filled with water, the cornea becomes again transparent. This want of transparency of the cornea is visible sometimes in dying people, owing to their inirritability, and consequent neglect of nictitation. The increase of transparency by filling the pores with fluid is seen by soaking white paper in oil; which from an opake body becomes very transparent, and accounts for a curious atmospheric phenomenon; when there exists a dry mist in a morning so as to render distant objects less distinct, it is a sign of a dry day; when distant objects are seen very distinct, it is a sign of rain. See Botan. Garden, Part I. add. note xxv. The particles of air are probably larger than those of water, as water will pass through leather and paper, which will confine air; hence when the atmosphere is much deprived of moisture, the pores of the dry air are so large, that the rays of light are refracted by their edges instead of passing through them. But when as much moisture is added as can be perfectly dissolved, the air becomes transparent; and opake again, when a part of this moisture collects into small spherules previous to its precipitation. This also accounts for the want of transparency of the air, which is seen in tremulous motions over corn-fields on hot summer-days, or over brick-kilns, after the flame is extinguished, while the furnace still remains hot. 2. _Deglutitio irritativa._ The deglutition of our saliva is performed frequently without our attention, and is then an irritative action in consequence of the stimulus of it in the mouth. Or perhaps sometimes for the purpose of diffusing a part of it over the dry membranes of the fauces and pharinx; in the same manner as tears are diffused over the cornea of the eye by the act of nictitation to clean or moisten it. 3. _Respiratio et Tussis irritativæ._ In the acts of respiration and of coughing there is an increased motion of the air-cells of the lungs owing to some stimulating cause, as described above in Class I. 1. 2. 8. and I. 1. 3. 4. and which are frequently performed without our attention or consciousness, and are then irritative actions; and thus differ from those described in Class II. 1. 1. 2. and 5. To these increased actions of the air-cells are superadded those of the intercostal muscles and diaphragm by irritative association. When any unnatural stimulus acts so violently on the organs of respiration as to induce pain, the sensorial power of sensation becomes added to that of irritation, and inflammation of the membranes of them is a general consequence. 4. _Exclusio bilis._ The exclusion of the bile from the gall-bladder, and its derivation into the duodenum, is an irritative action in consequence of the stimulus of the aliment on the extremity of the biliary duct, which terminates in the intestine. The increased secretion of tears is occasioned in a similar manner by any stimulating material in the eyes; which affects the excretory ducts of the lacrymal glands. A pain of the external membrane of the eye sometimes attends any unusual stimulus of it, then the sensorial power of sensation becomes added to that of irritation, and a superficial inflammation is induced. 5. _Dentitio._ Toothing. The pain of toothing often begins much earlier than is suspected; and is liable to produce convulsions; which are sometimes relieved, when the gum swells, and becomes inflamed; at other times a diarrhoea supervenes, which is generally esteemed a favourable circumstance, and seems to prevent the convulsions by supplying another means of relieving the pain of dentition by irritative exertion; and a consequent temporary exhaustion of sensorial power. See Class I. 1. 2. 5. Sect. XXXV. 2. 1. The convulsions from toothing generally commence long before the appearance of the teeth; but as the two middle incisors of the lower jaw generally appear first, and then those of the upper, it is adviseable to lance the gums over these longitudinally in respect to the jaw-bones, and quite down to the periosteum, and through it. As the convulsions attending the commencement of toothing are not only dangerous to life in their greatest degree, but are liable to induce stupor or insensibility by their continuance even in a less degree, the most efficacious means should be used to cure them. M. M. Lance the gum of the expected teeth quite through the periosteum longitudinally. Venesection by the lancet or by two or three leeches. One grain of calomel as a purge. Tincture of jalap, five or six drops in water every three hours til it purges, to be repeated daily. After evacuations a small blister on the back or behind the ears. And lastly, two or three drops of laudanum according to the age of the child. Warm bath. See Class III. 1. 1. 5. and 6. 6. _Priapismus chronicus._ I have seen two cases, where an erection of the penis, as hard as horn, continued two or three weeks without any venereal desires, but not without some pain; the easiest attitude of the patients was lying upon their backs with their knees up. At length the corpus cavernosum urethræ became soft, and in another day or two the whole subsided. In one of them a bougie was introduced, hoping to remove some bit of gravel from the caput gallinaginis, camphor, warm bathing, opium, lime-water, cold aspersion, bleeding in the veins of the penis, were tried in vain. One of them had been a free drinker, had much gutta rosacea on his face, and died suddenly a few months after his recovery from this complaint. Was it a paralysis of the terminations of the veins, which absorb the blood from the tumid penis? or from the stimulus of indurated semen in the seminal vessels? In the latter case some venereal desires should have attended. Class III. 1. 2. 16. The priapismus, which occurs to vigorous people in a morning before they awake, has been called the signum salutis, or banner of health, and is occasioned by the increase of our irritability or sensibility during sleep, as explained in Sect. XVIII. 15. 7. _Distentio mamularum._ The distention of the nipples of lactescent women is at first owing to the stimulus of the milk. See Sect. XIV. 8. and Sect. XVI. 5. See Class II. 1. 7. 10. 8. _Descensus uteri._ This is a very frequent complaint after bad labours, the fundus uteri becomes inverted and descends like the prolapsus ani. M. M. All the usual pessaries are very inconvenient and ineffectual. A piece of soft sponge about two inches diameter introduced into the vagina gives great ease to these patients, and supports the uterus; it should have a string put through it to retract it by. There are also pessaries now made of elastic gum, which are said to be easily worn, and to be convenient, from their having a perforation in their centre. 9. _Prolapsus ani._ The lower part of the rectum becomes inverted, and descends after every stool chiefly in children; and thus stimulates the sphincter ani like any other extraneous body. M. M. It should be dusted over with very fine powder of gum sandarach, and then replaced. Astringent fomentations; as an infusion of oak-bark, or a slight solution of alum. Horizontal rest frequently in the day. 10. _Lumbricus._ Round worm. The round worm is suspected in children when the belly is tumid, and the countenance bloated and pale, with swelling of the upper lip. The generation of these worms is promoted by the too dilute state of the bile, as is evident in the fleuke-worm found in the biliary ducts and substance of the liver in sheep; and in water-rats, in the livers of which last animals they were lately detected in large numbers by Dr. Capelle. Transactions of the college at Philadelphia, v. i. Now as the dilute state of the bile depends on the deficiency of the absorption of its thinner parts, it appears, that the tumid belly, and bloated countenance, and swelled upper lip, are a concomitant circumstance attending the general inactivity of the absorbent system; which is therefore to be esteemed the remote cause of the generation of worms. The simplicity of the structure of worms probably enables them to exist in more various temperatures of heat; and their being endued with life prevents them from being destroyed by digestion in the stomach, probably in the same manner as the powers of life prevent the fermentation and putrefaction of the stomach itself. Hence I conclude, that worms are originally taken into our alimentary canal from without; as I believe similar worms of all kinds are to be found out of the body. M. M. The round worm is destroyed by a cathartic with four or six grains of calomel; and afterwards by giving six or eight grains of filings of iron twice a day for a fortnight. See Hepatis tumor, Class I. 2. 3. 9. As worms are liable to come away in fevers, whether of the hectic or putrid kind, could they be removed by purulent matter, or rotten egg, or putrid flesh, since in those fevers from the enfeebled action of the intestines the fæces become highly putrid? 11. _Tænia._ Tape-worm consists of a chain of animals extending from the stomach to the anus. See Sect. XXXIX. 2. 3. It frequently exists in cats, rats, and geese, and probably in many other animals. The worms of this genus possess a wonderful power of retaining life. Two of them, which were voided by a pointer dog in consequence of violent purgatives, each of which were several feet in length, had boiling water poured on them in a bason; which seemed not much to inconvenience them. When the water was cool, they were taken out and put into gin or whiskey of the strongest kind, in which their life and activity continued unimpaired; and they were at length killed by adding to the spirit a quantity of corrosive sublimate. Medic. Comment. for 1791, p. 370. The tape-worm is cured by an amalgama of tin and quicksilver, such as is used on the back of looking-glasses; an ounce should be taken every two hours, till a pound is taken; and then a brisk cathartic of Glauber's salt two ounces, and common salts one ounce, dissolved in two wine pints of water, half a pint to be taken every hour till it purges. The worm extends from the stomach to the anus, and the amalgama tears it from the intestine by mechanical pressure, acting upon it the whole way. Electric shocks through the duodenum greatly assists the operation. Large doses of tin in powder. Iron filings in large doses. The powder of fern-root seems to be of no use, as recommended by M. Noufflier. 12. _Ascarides._ Thread-worms. These worms are said to be more frequent in some parts of this kingdom than in others, as near the fens of Lincolnshire. Do they escape from the body and become flies, like the bott-worm in horses? Do they crawl from one child to another in the same bed? Are they acquired from flies or worms, which are seen in putrid necessary houses, as these worms as well as the tapeworms, are probably acquired from without? this may account for their re-appearance a few weeks or months after they have been destroyed; or can this happen from the eggs or parts of them remaining? Ascarides appear to be of two kinds, the common small ones like a thread; which has a very sharp head, as appears in the microscope; and which is so tender, that the cold air soon renders it motionless; and a larger kind above an inch long, and nearly as thick as a very small crow-quill, and which is very hard in respect to its texture, and very tenacious of life. One of these last was brought to me, and was immediately immersed in a strong solution of sugar of lead, and lived in it a very long time without apparent inconvenience. M. M. Ascarides are said to be weakened by twenty grains of cinnabar and five of rhubarb taken every night, but not to be cured by this process. As these worms are found only in the rectum, variety of clysters have been recommended. I was informed of a case, where solutions of mercurial ointment were used as a clyster every night for a month without success. Clysters of Harrowgate water are recomended, either of the natural, or of the factitious, as described below, which might have a greater proportion of liver of sulphur in it. As the cold air soon destroys them, after they are voided, could clysters of iced water be used with advantage? or of spirit of wine and water? or of ether and water? Might not a piece of candle, about an inch long, or two such pieces, smeared with mercurial ointment, and introduced into the anus at night, or twice a day, be effectual by compressing their nidus, as well as by the poison of the mercury. The clysters should be large in quantity, that they may pass high in the rectum, as two drams of tobacco boiled a minute in a pint of water. Or perhaps what might be still more efficacious and less inconvenient, the smoke of tobacco injected by a proper apparatus every night, or alternate nights, for six or eight weeks. This was long since recommended, I think by Mr. Turner of Liverpool; and the reason it has not succeeded, I believe to have been owing to the imperfections of the joints of the common apparatus for injecting the smoke of tobacco, so that it did not pass into the intestine, though it was supposed to do so, as I once observed. The smoke should be received from the apparatus into a large bladder; and it may then be certainly injected like the common clyster with sufficient force; otherwise oiled leathers should be nicely put round the joints of the machine; and a wet cloth round the injecting pipe to prevent the return of the smoke by the sides of it. Clysters of carbonated hydrogen gas, or of other factitious airs, might be tried. Harrowgate water taken into the stomach, so as to induce six or seven stools every morning, for four or six weeks, is perhaps the most efficacious method in common use. A factitious Harrowgate water may be made probably of greater efficacy than the natural, by dissolving one ounce of marine salt, (called bay salt) and half an ounce of magnesia Glauber's salt, (called Epsom salt, or bitter purging salt) in twenty-eight ounces of water. A quarter or half a pint of this is to be taken every hour, or two hours in the morning, till it operates, with a tea-spoonful of a solution of liver of sulphur, which is to be made by putting an ounce of hepar sulphuris into half a pint of water. See Class IV. 1. 2. 9. 13. _Dracunculus._ A thin worm brought from the coast of Guinea. It is found in the interstices of the muscles, and is many yards long; it makes a small ulcer; which is cured by extracting an inch of the worm a day, and wrapping the extracted part slowly round a bit of tobacco pipe till next day, so as not to break it. I have twice seen long worms, like a thick horse-hair, in water in July in this country, which appeared hard and jointed. 14. _Morpiones._ Crab-lice. The excrement of this animal stains the linen, and appears like diluted blood. M. M. Spirit of wine. Mercurial ointment, shaving the part. Oil destroys other insects, if they be quite covered with it, as the ticks on dogs, and would probably therefore destroy these. Its manner of operation is by stopping up or filling their spiracula, or breathing pores; a few drops of oil poured on a wasp, so as to cover it, destroys it in a few seconds. 15. _Pediculi._ Lice. There is said to be a disease, in which these animals are propagated in indestructible numbers, so as to destroy the patient. M. M. Cleanliness, mercurial ointment, stavis acria in powder, or the tincture of it in spirit of wine. Spirit of wine alone? Bath of oil? * * * * * ORDO I. _Increased Irritation._ GENUS V. _With Increased Actions of the Organs of Sense._ SPECIES. 1. _Visus acrior._ Acuter sight. There have been instances of people, who could see better in the gloom of the evening, than in the stronger light of the day; like owls, and bats, and many quadrupeds, and flying insects. When the eye is inflamed, great light becomes eminently painful, owing to the increased irritative motions of the retina, and the consequent increased sensation. Thus when the eye is dazzled with sudden light, the pain is not owing to the motion of the iris; for it is the contraction of the iris, which relieves the pain from sudden light; but to the too violent contractions of the moving fibres, which constitute the extremities of the optic nerve. 2. _Auditus acrior._ The irritative ideas of hearing are so increased in energy as to excite our attention. This happens in some diseases of the epileptic kind, and in some fevers. Hence the whispering of the currents of air in a room, the respiration of the company, and noises before unperceived, become troublesome; and sounds louder than usual, or unexpected, produce starting, and convulsions. M. M. Put oil of almonds into the ears. Stop the meatus auditorius with cotton wool. Set the feet of the patient's bed on cushions, or suspend it by cords from the ceiling. 3. _Olfactus acrior._ The irritative ideas of smell from the increased action of the olfactive nerve excite our attention. Hence common odours are disagreeable; and are perceived from variety of objects, which were before thought inodorous. These are commonly believed to be hallucinations of the sense. M. M. Snuff starch up the nostrils. 4. _Gustus acrior._ The irritative ideas of taste, as of our own saliva, and even of the atmospheric air, excite our attention; and common tastes are disagreeably strong. M. M. Water. Mucilage. Vegetable acids. Scrape the tongue clean. Rub it with a sage-leaf and vinegar. 5. _Tactus acrior._ The irritative ideas of the nerves of touch excite our attention: hence our own pressure on the parts, we rest upon, becomes uneasy with universal soreness. M. M. Soft feather-bed. Combed wool put under the patients, which rolls under them, as they turn, and thus prevents their friction against the sheets. Drawers of soft leather. Plasters of cerate with calamy. 6. _Sensus caloris acrior._ Acuter sense of heat occurs in some diseases, and that even when the perceptible heat does not appear greater than natural to the hand of another person. See Class I. 1. 2. See Sect. XIV. 8. All the above increased actions of our organs of sense separately or jointly accompany some fevers, and some epileptic diseases; the patients complaining of the perception of the least light, noises in their ears, bad smells in the room, and bad tastes in their mouths, with soreness, numbness, and other uneasy feels, and with disagreeable sensations of general or partial heat. 7. _Sensus extensionis acrior._ Acuter sense of extension. The sense of extension was spoken of in Sect. XIV. 7. and XXXII. 4. The defect of distention in the arterial system is accompanied with faintness; and its excess with sensations of fulness, or weight, or pressure. This however refers only to the vascular muscles, which are distended by their appropriated fluids; but the longitudinal muscles are also affected by different quantities of extension, and become violently painful by the excess of it. These pains of muscles and of membranes are generally divided into acute and dull pains. The former are generally owing to increase of extension, as in pricking the skin with a needle; and the latter generally to defect of extension, as in cold head-aches; but if the edge of a knife, or point of a pin, be gradually pressed against the fibres of muscles or membranes, there would seem to be three states or stages of this extension of the fibres; which have acquired names according to the degree or kind of sensation produced by the extension of them; these are 1. titillation or tickling. 2. itching, and the 3. smarting; as described below. See Sect. XIV. 9. 8. _Titillatio._ Tickling is a pleasureable pain of the sense of extension above mentioned, and therefore excites laughter; as described in Sect. XXXIV. 1. 4. The tickling of the nostrils, which precedes the efforts of sneezing, is owing to the increased irritation occasioned by external stimulus; and is attended with a pleasureable sensation in consequence of the increased action of the part. When this action is exerted in a greater degree, the sensation becomes painful, and the convulsion of sneezing ensues; as the pain in tickling the soles of the feet of children is relieved by laughter. A lady after a bruise on her nose by a fall was affected with incessant sneezing, and relieved by snuffing starch up her nostrils. Perpetual sneezings in the measles, and in catarrhs from cold, are owing to the stimulus of the saline part of the mucous effusion on the membrane of the nostrils. See Class II. 1. 1. 3. 9. _Pruritus._ Itching seems to be a greater degree of titillation, and to be owing to the stimulus of some acrid material, as the matter of the itch; or of the herpes on the scrotum, and about the anus; or from those universal eruptions, which attend some elderly people, who have drank much vinous spirit. It occurs also, when inflammations are declining, as in the healing of blisters, or in the cure of ophthalmia, as the action of the vessels is yet so great as to produce sensation; which, like the titillations that occasion laughter, is perpetually changing from pleasure to pain. When the natural efforts of scratching do not relieve the pain of itching, it sometimes increases so as to induce convulsions and madness. As in the furor uterinus, and satyriasis, and in the sphincter ani and scrotum. See Class II. 1. 4. 14. IV. 2. 2. 6. M. M. Warm bath. Fomentation. Alcohol externally. Poultice. Oiled silk. Mercurial ointments on small surfaces at once. See Class II. 1. 4. 12. Solutions of lead on small surfaces at once. 10. _Dolor urens._ Smarting follows the edge of a knife in making a wound, and seems to be owing to the distention of a part of a fibre, till it breaks. A smarting of the skin is liable to affect the scars left by herpes or shingles; and the callous parts of the bottoms of the feet; and around the bases of corns on the toes; and frequently extends after sciatica along the outside of the thigh, and of the leg, and part of the foot. All these may be owing to the stimulus of extension, by blood or serum being forced into vessels nearly coalesced. M. M. Emplastrum de minio put like a bandage on the part. Warm fomentation. Oil and camphor rubbed on the part. Oil-silk covering. A blister on the part. Ether, or alcohol, suffered to evaporate on the part. 11. _Consternatio._ Surprise. As our eyes acquaint us at the same time with less than half of the objects, which surround us, we have learned to confide much in the organ of hearing to warn us of approaching dangers. Hence it happens, that if any sound strikes us, which we cannot immediately account for, our fears are instantly alarmed. Thus in great debility of body, the loud clapping of a door, or the fall of a fire-shovel, produces alarm, and sometimes even convulsions; the same occurs from unexpected sights, and in the dark from unexpected objects of touch. In these cases the irritability is less than natural, though it is erroneously supposed to be greater; and the mind is busied in exciting a train of ideas inattentive to external objects; when this train of ideas is dissevered by any unexpected stimulus, surprise is excited; as explained in Sect. XVII. 3. 7. and XVIII. 17. then as the sensibility in these cases is greater, fear becomes superadded to the surprise; and convulsions in consequence of the pain of fear. See Sect. XIX. 2. The proximate cause of surprise is the increased irritation induced by some violent stimulus, which dissevers our usual trains of ideas; but in diseases of inirritability the frequent starting or surprise from sounds not uncommon, but rather louder than usual, as the clapping of a door, shews, that the attention of the patient to a train of sensitive ideas was previously stronger than natural, and indicates an incipient delirium; which is therefore worth attending to in febrile diseases. * * * * * ORDO II. _Decreased Irritation._ GENUS I. _With decreased Action of the Sanguiferous System._ The reader should be here apprized, that the words strength and debility, when applied to animal motions, may properly express the quantity of resistance such motions may overcome; but that, when they are applied to mean the susceptibility or insusceptibility of animal fibres to motion, they become metaphorical terms; as in Sect. XII. 2. 1. and would be better expressed by the words activity and inactivity. There are three sources of animal inactivity; first, the defect of the natural quantity of stimulus on those fibres, which have been accustomed to perpetual stimulus; as the arterial and secerning systems. When their accustomed stimulus is for a while intermitted, as when snow is applied to the skin of the hands, an accumulation of sensorial power is produced; and then a degree of stimulus, as of heat, somewhat greater than that at present applied, though much less than the natural quantity, excites the vessels of the skin into violent action. We must observe, that a deficiency of stimulus in those fibres, which are not subject to perpetual stimulus, as the locomotive muscles, is not succeeded by accumulation of sensorial power; these therefore are more liable to become permanently inactive after a diminution of stimulus; as in strokes of the palsy, this may be called inactivity from defect of stimulus. 2. A second source of animal inactivity exists, when the sensorial power in any part of the system has been previously exhausted by violent stimuli; as the eyes after long exposure to great light; or the stomach, to repeated spirituous potation; this may be termed inactivity from exhaustion of sensorial power. See Sect. XII. 2. 1. 3. But there is a third source of inactivity owing to the deficient production of sensorial power in the brain; and hence stimuli stronger than natural are required to produce the accustomed motions of the arterial system; in this case there is no accumulation of sensorial power produced; as in the inactivity owing to defect of stimulus; nor any previous exhaustion of it, as in the inactivity owing to excess of stimulus. This third kind of inactivity causes many of the diseases of this genus; which are therefore in general to be remedied by such medicines as promote a greater production of sensorial power in the brain; as the incitantia, consisting of wine, beer, and opium, in small repeated quantities; and secondly of such as simply stimulate the arterial and glandular system into their natural actions; as small repeated blisters, spices, and essential oils. And lastly the sorbentia, which contribute to supply the more permanent strength of the system, by promoting the absorption of nourishment from the stomach, and intestines; and of the superfluous fluid, which attends the secretions. SPECIES. 1. _Febris inirritativa._ Inirritative fever. This is the typhus mitior, or nervous fever of some writers; it is attended with weak pulse without inflammation, or symptoms of putridity, as they have been called. When the production of sensorial power in the brain is less than usual, the pulse becomes quick as well as weak; and the heart sometimes trembles like the limbs of old age, or of enfeebled drunkards; and when this force of the contractions of the heart and arteries is diminished, the blood is pushed on with less energy, as well as in less quantity, and thence its stimulus on their sides is diminished in a duplicate ratio. In compressions of the brain, as in apoplexy, the pulse becomes slower and fuller; for in that disease, as in natural sleep, the irritative motions of the heart and arteries are not diminished, volition alone is suspended or destroyed. If the absorption of the terminations of the veins is not equally impaired with the force of the heart and arteries, the blood is taken up by the veins the instant it arrives at their extremities; the capillary vessels are left empty, and there is less resistance to the current of the blood from the arteries; hence the pulse becomes empty, as well as weak and quick; the veins of the skin are fuller than the arteries of it; and its appearance becomes pale, bluish, and shrunk. See Class II. 1. 3. 1. When this pulse persists many hours, it constitutes the febris inirritativa, or typhus, or nervous fever, of some writers; it is attended with little heat, the urine is generally of a natural colour, though in less quantity; with great prostration of strength, and much disturbance of the faculties of the mind. Its immediate cause seems to be a deficient secretion of the sensorial power from the inaction of the brain; hence almost the whole of the sensorial power is expended in the performance of the motions necessary to life, and little of it can be spared for the voluntary actions of the locomotive muscles, or organs of sense, see Class I. 2. 5. 3. Its more remote cause may be from a paralysis or death of some other part of the body; as of the spleen, when a tumour is felt on the left side, as in some intermittents; or of the kidnies, when the urine continues pale and in small quantity. Does the revivescence of these affected parts, or their torpor, recurring at intervals, form the paroxysms of these fevers? and their permanent revivescence establish the cure? See Class IV. 2. 1. 19. M. M. Wine and opium in small quantities repeated every three hours alternately; small repeated blisters; warm but fresh air; sorbentia; nutrientia; transfusion of blood. Small electric shocks passed through the brain in all directions. Oxygene air? 2. _Paresis inirritativa._ Inirritative debility. A defective action of the irritative motions without increase of the frequency of the pulse. It continues three or four weeks like a fever, and then either terminates in health, or the patient sinks into one kind of apoplexy, and perishes. Many symptoms, which attend inirritative fevers, accompany this disease, as cold hands and feet at periodic times, scurf on the tongue, want of appetite, muddy urine, with pains of the head, and sometimes vertigo, and vomiting. This disease differs from the inirritative fever by the pulse not being more frequent than in health. The want of appetite and of digestion is a principal symptom, and probably is the cause of the universal debility, which may be occasioned by the want of nourishment. The vertigo is a symptom of inirritability, as shewn in Class IV. 2. 1. 16. the muddy urine is owing to increased absorption from the bladder in consequence of the diminished cutaneous and cellular absorption, as in anasarca, explained in Sect. XXIX. 5. 1. and is therefore a consequence of the inirritability of that part of the system; the foul tongue is owing to an increased absorption of the thinner part of the mucus in consequence of the general deficiency of fluid, which should be absorbed by the skin and stomach. The sickness is owing to decreased action of the stomach, which is probably the primary disease, and is connected with the vertigo. M. M. An emetic. Calomel, grains iv. once or twice. Then a blister. Peruvian bark. Valerian. Columbo. Steel. Opium and wine in small quantities, repeated alternately every three hours. Small electric percussions through the stomach. 3. _Somnus interruptus._ Interrupted sleep. In some fevers, where the inirritability is very great, when the patient falls asleep, the pulse in a few minutes becomes irregular, and the patient awakes in great disorder, and fear of dying, refusing to sleep again from the terror of this uneasy sensation. In this extreme debility there is reason to believe, that some voluntary power during our waking hours is employed to aid the irritative stimuli in carrying on the circulation of the blood through the lungs; in the same manner as we use voluntary exertions, when we listen to weak sounds, or wish to view an object by a small light; in sleep volition is suspended, and the deficient irritation alone is not sufficient to carry on the pulmonary circulation. This explanation seems the most probable one, because in cases of apoplexy the irritative motions of the arterial system do not seem to be impaired, nor in common sleep. See Incubus III. 2. 1. 13. M. M. Opium in very small doses, as three drops of laudanum. A person should watch the patient, and awaken him frequently; or he should measure the time between slumber and slumber by a stop-watch, and awaken the patient a little before he would otherwise awake; or he should keep his finger on the pulse, and should forcibly awaken him, as soon as it becomes irregular, before the disorder of the circulation becomes so great as to disturb him. See Class I. 2. 1. 9. and Sect. XXVII. 2. 4. _Syncope._ Fainting consists in the decreased action of the arterial system; which is sometimes occasioned by defect of the stimulus of distention, as after venesection, or tapping for the dropsy. At other times it arises from great emotions of the mind, as in sudden joy or grief. In these cases the whole sensorial power is exerted on these interesting ideas, and becomes exhausted. Thus during great surprise or fear the heart stops for a time, and then proceeds with throbbing and agitation; and sometimes the vital motions become so deranged, as never to recover their natural successive action; as when children have been frightened into convulsions. See Sect. XII. 7. 1. Miss ----, a young lady of Stafford, in travelling in a chaise was so affected by seeing the fall of a horse and postillion, in going down a hill, though the carriage was not overturned, that she fainted away, and then became convulsed, and never spoke afterwards; though she lived about three days in successive convulsions and stupor. 5. _Hæmorrhagia venosa._ A bleeding from the capillaries arising from defect of venous absorption, as in some of those fevers commonly termed putrid. When the blood stagnates in the cellular membrane, it produces petechiæ from this torpor or paralysis of the absorbent mouths of the veins. It must be observed, that those people who have diseased livers, are more liable to this kind of hæmorrhages, as well as to the hæmorrhagia arteriosa; the former, because patients with diseased livers are more subject to paralytic complaints in general, as to hemiplegia, and to dropsy, which is a paralysis of the lymphatics; and the latter is probably owing to the delay of the circulation in the vena porta by the torpor of this hepatic vessel, when the liver is not much enlarged; and to its pressure on the vena cava, when it is much enlarged. M. M. Vitriolic acid, opium, steel, bark. Sponge bound on the part. Steel dissolved in spirit of wine externally. Flour. 6. _Hæmorrhois cruenta._ In the bleeding piles the capillary vessels of the rectum become distended and painful from the defect of the venous absorption of the part, and at length burst; or the mucous glands are so dilated as to give a passage to the blood; it is said to observe lunar periods. M. M. Venesection, poultices, cathartics, spice, cold bath, and sorbentia. External compression by applying lint, sponge, or cotton. Internal compression by applying a bit of candle smeared with mercurial ointment. Strangulate the tumid piles with a silk string. Cut them off. See Class I. 2. 3. 22. Mrs. ---- had for twelve or fifteen years, at intervals of a year or less, a bleeding from the rectum without pain; which however stopped spontaneously after she became weakened, or by the use of injections of brandy and water. Lately the bleeding continued above two months, in the quantity of many ounces a day, till she became pale and feeble to an alarming degree. Injections of solutions of lead, of bark and salt of steel, and of turpentine, with some internal astringents, and opiates, were used in vain. An injection of the smoke of tobacco, with ten grains of opium mixed with the tobacco, was used, but without effect the two first times on account of the imperfection of the machine; on the third time it produced great sickness, and vertigo, and nearly a fainting fit; from which time the blood entirely stopped. Was this owing to a fungous excrescence in the rectum; or to a blood-vessel being burst from the difficulty of the blood passing through the vena porta from some hepatic obstruction, and which had continued to bleed so long? Was it stopped at last by the fainting fit? or by the stimulus of the tobacco? 7. _Hæmorrhagia renum._ Hæmorrhage from the kidnies, when attended with no pain, is owing to defect of venous absorption in the kidney. When attended with pain on motion, it is owing to a bit of gravel in the ureter or pelvis of the kidney; which is a much more frequent disease than the former. See Sect. XXVII. 1. M. M. 1. Venesection in small quantity, calomel, bark, steel, an opiate; cold immersion up to the navel, the upper part of the body being kept cloathed. Neville-Holt water. 2. Alcalized water aerated. Much diluent liquids. Cool dress. Cool bed-room. Cows are much subject to bloody urine, called foul water by the farmers; in this disease about sixty grains of opium with or without as much rust of iron, given twice a day, in a ball mixed with flour and water, or dissolved in warm water, or warm ale, is, I believe, an efficacious remedy, to which however should be added about two quarts of barley or oats twice a day, and a cover at night, if the weather be cold. 8. _Hæmorrhagia Hepatis._ Hæmorrhage from the liver. It sometimes happens in those, who have the gutta rosea, or paralytic affections owing to diseased livers induced by the potation of fermented liquors, that a great discharge of black viscid blood occasionally comes away by stool, and sometimes by vomiting: this the ancients called Melancholia, black bile. If it was bile, a small quantity of it would become yellow or green on dilution with warm water, which was not the case in one experiment which I tried; it must remain some time in the intestines from its black colour, when it passes downwards, and probably comes from the bile-ducts, and is often a fatal symptom. When it is evacuated by vomiting it is less dangerous, because it shews greater remaining irritability of the intestinal canal, and is sometimes salutary to those who have diseased livers. M. M. An emetic. Rhubarb, steel, wine, bark. 9. _Hæmoptoe venosa._ Venous hæmoptoe frequently attends the beginning of the hereditary consumptions of dark-eyed people; and in others, whose lungs have too little irritability. These spittings of blood are generally in very small quantity, as a tea-spoonful; and return at first periodically, as about once a month; and are less dangerous in the female than in the male sex; as in the former they are often relieved by the natural periods of the menses. Many of these patients are attacked with this pulmonary hæmorrhage in their first sleep; because in feeble people the power of volition is necessary, besides that of irritation, to carry on respiration perfectly; but, as volition is suspended during sleep, a part of the blood is delayed in the vessels of the lungs, and in consequence effused, and the patient awakes from the disagreeable sensation. See Class I. 2. 1. 3. II. 1. 6. 6. III. 2. 1. 10. M. M. Wake the patient every two or three hours by an alarum clock. Give half a grain of opium at going to bed, or twice a day. Onions, garlic, slight chalybeates. Issues. Leeches applied once a fortnight or month to the hemorrhoidal veins to produce a new habit. Emetics after each period of hæmoptoe, to promote expectoration, and dislodge any effused blood, which might by remaining in the lungs produce ulcers by its putridity. A hard bed, to prevent too sound sleep. A periodical emetic or cathartic once a fortnight. 10. _Palpitatio cordis._ The palpitation of the heart frequently attends the hæmoptoe above mentioned; and consists in an ineffectual exertion of the heart to push forwards its contents in due time, and with due force. The remote cause is frequently some impediment to the general circulation; as the torpor of the capillaries in cold paroxysms of fever, or great adhesions of the lungs. At other times it arises from the debility of the action of the heart owing to the deficient sensorial power of irritation or of association, as at the approach of death. In both these cases of weak exertion the heart feels large to the touch, as it does not completely empty itself at each contraction; and on that account contracts more frequently, as described in Sect. XXXII. 2. 2. Another kind of palpitation may sometimes arise from the retrograde motions of the heart, as in fear. See Class I. 3. 1. 2. and IV. 3. 1. 6. 11. _Menorrhagia._ Continued flow of the catamenia. The monthly effusion of blood from the uterus or vagina is owing to a torpor of the veins of those membranes in consequence of the defect of venereal stimulus; and in this respect resembles the mucus discharged in the periodical venereal orgasm of the female quadrupeds, which are secluded from the males. The menorrhagia, or continued flow of this discharge, is owing to a continued defect of the venous absorption of the membranes of the uterus or vagina. See Class IV. 2. 4. 7. M. M. Venesection in small quantity. A cathartic. Then opium, a grain every night. Steel. Bark. A blister. Topical aspersion with cold water, or cold vinegar. 12. _Dysmenorrhagia._ A difficulty of menstruation attended with pain. In this complaint the torpor of the uterine vessels, which precedes menstruation, is by sympathy accompanied with a torpor of the lumbar membranes, and consequent pain; and frequently with cold extremities, and general debility. The small quantity and difficulty of the discharge is owing to arterial inactivity, as in chlorosis. Whence it happens, that chalybeate medicines are of efficacy both to stop or prevent too great menstruation, and to promote or increase deficient menstruation; as the former is owing to inirritability of the veins, and the latter of the arteries of the uterus. See Article IV. 2. 6. in the Materia Medica. M. M. Opium, steel, pediluvium. Warm bath. 13. _Lochia nimia._ Too great discharge after delivery. In that unnatural practice of some hasty accoucheurs of introducing the hand into the uterus immediately after the delivery of the child, and forcibly bringing away the placenta, it frequently happens, that a part of it is left behind; and the uterus, not having power to exclude so small a portion of it, is prevented from complete contraction, and a great hæmorrhage ensues. In this circumstance a bandage with a thick compress on the lower part of the belly, by appressing the sides of the uterus on the remaining part of the placenta, is likely to check the hæmorrhage, like the application of a pledget of any soft substance on a bleeding vessel. In other cases the lochia continues too long, or in too great quantity, owing to the deficiency of venous absorption. M. M. An enema. An opiate. A blister. Slight chalybeates. Peruvian bark. Clothes dipped in cold vinegar and applied externally. Bandages on the limbs to keep more blood in them for a time have been recommended. 14. _Abortio spontanea._ Some delicate ladies are perpetually liable to spontaneous abortion, before the third, or after the seventh, month of gestation. From some of these patients I have learnt, that they have awakened with a slight degree of difficult respiration, so as to induce them to rise hastily up in bed; and have hence suspected, that this was a tendency to a kind of asthma, owing to a deficient absorption of blood in the extremities of the pulmonary or bronchial veins; and have concluded from thence, that there was generally a deficiency of venous absorption; and that this was the occasion of their frequent abortion. Which is further countenanced, where a great sanguinary discharge precedes or follows the exclusion of the fetus. M. M. Opium, bark, chalybeates in small quantity. Change to a warmer climate. I have directed with success in four cases half a grain of opium twice a day for a fortnight, and then a whole grain twice a day during the whole gestation. One of these patients took besides twenty grains of Peruvian bark for several weeks. By these means being exactly and regularly persisted in, a new habit became established, and the usual miscarriages were prevented. Miscarriages more frequently happen from eruptive fevers, and from rheumatic ones, than from other inflammatory diseases. I saw a most violent pleurisy and hepatitis cured by repeated venesection about a week or ten days before parturition; yet another lady whom I attended, miscarried at the end of the chicken pox, with which her children were at the same time affected. Miscarriages towards the termination of the small pox are very frequent, yet there have been a few instances of children, who have been born with the eruption on them. The blood in the small pox will not inoculate that disease, if taken before the commencement of the secondary fever; as shewn in Sect. XXXIII. 2. 10. because the contagious matter is not yet formed, but after it has been oxygenated through the cuticle in the pustules, it becomes contagious; and if it be then absorbed, as in the secondary fever, the blood of the mother may become contagious, and infect the child. The same mode of reasoning is applicable to the chicken pox. See Class IV. 3. 1. 7. 15. _Scorbutus._ Sea-scurvy is caused by salt diet, the perpetual stimulus of which debilitates the venous and absorbent systems. Hence the blood is imperfectly taken up by the veins from the capillaries, whence brown and black spots appear upon the skin without fever. The limbs become livid and edematous, and lastly ulcers are produced from deficient absorption. See Sect. XXXIII. 3. 2. and Class II. 1. 4. 13. For an account of the scurvy of the lungs, see Sect. XXVII. 2. M. M. Fresh animal and vegetable food. Infusion of malt. New beer. Sugar. Wine. Steel. Bark. Sorbentia. Opium? 16. _Vibices._ Extravasations of blood become black from their being secluded from the air. The extravasation of blood in bruises, or in some fevers, or after death in some patients, especially in the parts which were exposed to pressure, is owing to the fine terminations of the veins having been mechanically compressed so as to prevent their absorbing the blood from the capillaries, or to their inactivity from disease. The blood when extravasated undergoes a chemical change before it is sufficiently fluid to be taken up by the lymphatic absorbents, and in that process changes its colour to green and then yellow. 17. _Petechiæ._ Purple spots. These attend fevers with great venous inirritability, and are probably formed by the inability of a single termination of a vein, whence the corresponding capillary becomes ruptured, and effuses the blood into the cellular membrane round the inert termination of the vein. This is generally esteemed a sign of the putrid state of the blood, or that state contrary to the inflammatory one. As it attends some inflammatory diseases which are attended with great inirritability, as in the confluent small pox. But it also attends the scurvy, where no fever exists, and it therefore simply announces the inactivity of the terminations of some veins; and is thence indeed a bad symptom in fevers, as a mark of approaching inactivity of the whole sanguiferous system, or death. The blue colour of some children's arms or faces in very cold weather is owing in like manner to the torpor of the absorbent terminations of the veins, whence the blood is accumulated in them, and sometimes bursts them. * * * * * ORDO II. _Decreased Irritation._ GENUS II. _Decreased Action of the Secerning System._ These are always attended with decrease of partial, or of general heat; for as the heat of animal bodies is the consequence of their various secretions, and is perpetually passing away into the ambient air, or other bodies in contact with them; when these secretions become diminished, or cease, the heat of the part or of the whole is soon diminished, or ceases along with them. SPECIES. 1. _Frigus febrile._ Febrile coldness. There is reason to believe, that the beginning of many fever-fits originates in the quiescence of some part of the absorbent system, especially where they have been owing to external cold; but that, where the coldness of the body is not owing to a diminution of external heat, it arises from the inaction of some part of the secerning system. Hence some parts of the body are hot whilst other parts are cold; which I suppose gave occasion to error in Martyn's Experiments; where he says, that the body is as hot in the cold paroxysms of fevers as at other times. After the sensorial power has been much diminished by great preceding activity of the system, as by long continued external heat, or violent exercise, a sudden exposure to much cold produces a torpor both greater in degree and over a greater portion of the system, by subtracting their accustomed stimulus from parts already much deprived of their irritability. Dr. Franklin in a letter to M. Duberge, the French translator of his works, mentions an instance of four young men, who bathed in a cold spring after a day's harvest work; of whom two died on the spot, a third on the next morning, and the other survived with difficulty. Hence it would appear, that those, who have to travel in intensely cold weather, will sooner perish, who have previously heated themselves much with drams, than those who have only the stimulus of natural food; of which I have heard one well attested instance. See Article VII. 2. 3. Class III. 2. 1. 17. _Frigus chronicum._ Permanent coldness. Coldness of the extremities, without fever, with dry pale skin, is a symptom of general debility, owing to the decreased action of the arterial system, and of the capillary vessels; whence the perspirable matter is secreted in less quantity, and in consequence the skin is less warm. This coldness is observable at the extremities of the limbs, ears, and nose, more than in any other parts: as a larger surface is here exposed to the contact of the air, or clothes, and thence the heat is more hastily carried away. The pain, which accompanies the coldness of the skin, is owing to the deficient exertion of the subcutaneous vessels, and probably to the accumulation of sensorial power in the extremities of their nerves. See Sect. XII. 5. 3. XIV. 6. XXXII. 3. and Class I. 2. 4. 1. M. M. A blister. Incitantia, nutrientia, sorbentia. Exercise. Clothes. Fire. Joy. Anger. 2. _Pallor fugitivus._ The fugitive paleness, which accompanies the coldness of the extremities, is owing to a less quantity of blood passing through the capillaries of the skin in a given time; where the absorbent power of the veins is at the same time much diminished, a part of the blood lingers at their junction with the capillary arteries, and a bluish tinge is mixed with the paleness; as is seen in the loose skin under the eye-lids, and is always a mark of temporary debility. See Class II. 1. 4. 4. Where the paleness of the skin is owing to the deficiency of red globules in the blood, it is joined with a yellowish tinge; which is the colour of the serum, with which the blood then abounds, as in chlorosis, and in torpor or paralysis of the liver, and is often mistaken for a superabundance of bile. A permanent paleness of the skin is owing to the coalescence of the minute arteries, as in old age. See Class I. 2. 2. 9. There is another source of paleness from the increased absorption of the terminations of the veins, as when vinegar is applied to the lips. See Sect. XXVII. 1. and another from the retrograde motions of the capillaries and fine extremities of the arteries. See Class II. 3. 1. 1. M. M. A blister, nutrientia, incitantia, exercise, oxygene gas. 3. _Pus parcius._ Diminished pus. Dryness of ulcers. In the cold fits of fever all the secretions are diminished, whether natural or artificial, as their quantity depends on the actions of the glands or capillaries, which then share in the universal inaction of the system. Hence the dryness of issues and blisters in great debility, and before the approach of death, is owing to deficient secretion, and not to increased absorption. M. M. Opium, wine in very small quantities, Peruvian bark. 4. _Mucus parcior._ Diminished mucus. Dryness of the mouth and nostrils. This also occurs in the cold fits of intermittents. In these cases I have also found the tongue cold to the touch of the finger, and the breath to the back of one's hand, when opposed to it, which are very inauspicious symptoms, and generally fatal. In fevers with inirritability it is generally esteemed a good symptom, when the nostrils and tongue become moist after having been previously dry; as it shews an increased action of the mucous glands of those membranes, which were before torpid. And the contrary to this is the facies Hippocratica, or countenance so well described by Hippocrates, which is pale, cold, and shrunk; all which are owing to the inactivity of the secerning vessels, the paleness from there being less red blood passing through the capillaries, the coldness of the skin from there being less secretion of perspirable matter, and the shrunk appearance from there being less mucus secreted into the cells of the cellular membrane. See Class IV. 2. 4. 11. M. M. Blisters. Incitantia. 5. _Urina parcior pallida._ Paucity of pale urine, as in the cold fits of intermittents; it appears in some nervous fevers throughout the whole disease, and seems to proceed from a palsy of the kidnies; which probably was the cause of the fever, as the fever sometimes ceases, when that symptom is removed: hence the straw-coloured urine in this fever is so far salutary, as it shews the unimpaired action of the kidnies. M. M. Balsams, essential oil, asparagus, rhubarb, a blister. Cantharides internally. 6. _Torpor hepaticus._ Paucity of bile from a partial inaction of the liver; hence the bombycinous colour of the skin, grey stools, urine not yellow, indigestion, debility, followed by tympany, dropsy, and death. This paralysis or inirritability of the liver often destroys those who have been long habituated to much fermented liquor, and have suddenly omitted the use of it. It also destroys plumbers, and house-painters, and in them seems a substitute for the colica saturnina. See Sect. XXX. M. M. Aloe and calomel, then the bark, and chalybeates. Mercurial ointment rubbed on the region of the liver. Rhubarb, three or four grains, with opium half a grain to a grain twice a day. Equitation, warm bath for half an hour everyday. 7. _Torpor Pancreatis._ Torpor of the pancreas. I saw what I conjectured to be a tumour of the pancreas with indigestion, and which terminated in the death of the patient. He had been for many years a great consumer of tobacco, insomuch that he chewed that noxious drug all the morning, and smoaked it all the afternoon. As the secretion from the pancreas resembles saliva in its general appearance, and probably in its office of assisting digestion, by preventing the fermentation of the aliment; as would appear by the experiments of Pringle and Macbride; there is reason to suspect, that a sympathy may exist between the salivary and pancreatic glands; and that the perpetual stimulus of the former by tobacco might in process of time injure the latter. See Tobacco, Article III. 2. 2. 8. _Torpor renis._ Inirritability or paralysis of the kidnies is probably frequently mistaken for gravel in them. Several, who have lived rather intemperately in respect to fermented or spirituous liquors, become suddenly seized about the age of sixty, or later, with a total stoppage of urine; though they have previously had no symptoms of gravel. In these cases there is no water in the bladder; as is known by the introduction of the catheter, of which those made of elastic gum are said to be preferable to metallic ones; or it may generally be known by the shape of the abdomen, either by the eye or hand. Bougies and catheters of elastic gum are sold at N^o 37, Red Lion-street, Holborn, London. M. M. Electric shocks, warm bath. Emetics. See calculus renis, Class I. 1. 3. 9. When no gravel has been previously observed, and the patient has been a wine-drinker rather than an ale-drinker, the case is generally owing to inirritability of the tubuli uriniferi, and is frequently fatal. See Class I. 2. 4. 20. 9. _Punctæ mucosæ vultûs._ Mucous spots on the face. These are owing to the inactivity of the excretory ducts of the mucous glands; the thinner part of this secretion exhales, and the remainder becomes inspissated, and lodges in the duct; the extremity of which becomes black by exposure to the air. M. M. They may be pressed out by the finger-nails. Warm water. Ether frequently applied. Blister on the part? 10. _Maculæ cutis fulvæ._ Morphew or freckles. Tawny blotches on the skin of the face and arms of elderly people, and frequently on their legs after slight erysipelas. The freckles on the face of younger people, who have red hair, seem to be a similar production, and seem all to be caused by the coalescence of the minute arteries or capillaries of the part. In a scar after a wound the integument is only opake; but in these blotches, which are called morphew and freckles, the small vessels seem to have become inactive with some of the serum of the blood stagnating in them, from whence their colour. See Class III. 1. 2. 12. M. M. Warm bathing. A blister on the part? 11. _Canities._ Grey hair. In the injection of the vessels of animals for the purposes of anatomical preparations, the colour of the injected fluid will not pass into many very minute vessels; which nevertheless uncoloured water, or spirits, or quicksilver will permeate. The same occurs in the filtration of some coloured fluids through paper, or very fine sand, where the colouring matter is not perfectly dissolved, but only diffused through the liquid. This has led some to imagine, that the cause of the whiteness of the hair in elderly people may arise from the diminution, or greater tenuity, of the glandular vessels, which secrete the mucus, which hardens into hair; and that the same difference of the tenuity of the secerning vessels may possibly make the difference of colour of the silk from different silk-worms, which is of all shades from yellow to white. But as the secreted fluids are not the consequence of mechanical filtration, but of animal selection; we must look out for another cause, which must be found in the decreasing activity of the glands, as we advance in life; and which affects many of our other secretions as well as that of the mucus, which forms the hair. Hence grey hairs are produced on the faces of horses by whatever injures the glands at their roots, as by corrosive blisters; and frequently on the human subject by external injuries on the head; and sometimes by fevers. And as the grey colour of hair consists in its want of transparency, like water converted into snow; there is reason to suppose, that a defect of secreted moisture simply may be the cause of this kind of opacity, as explained in Cataracta, Class I. 2. 2. 13. M. M. Whatever prevents the inirritability and insensibility of the system, that is, whatever prevents the approach of old age, will so far counteract the production of grey hairs, which is a symptom of it. For this purpose in people, who are not corpulent, and perhaps in those who are so, the warm bath twice or thrice a week is particularly serviceable. See Sect. XXXIX. 5. 1. on the colours of animals, and Class I. 1. 2. 15. 12. _Callus._ The callous skin on the hands and feet of laborious people is owing to the extreme vessels coalescing from the perpetual pressure they are exposed to. As we advance in life, the finer arteries lose their power of action, and their sides grow together; hence the paleness of the skins of elderly people, and the loss of that bloom, which is owing to the numerous fine arteries, and the transparency of the skin, that encloses them. M. M. Warm bath. Paring the thick skin with a knife. Smoothing it with a pumice stone. Cover the part with oiled silk to prevent the evaporation of the perspirable matter, and thus to keep it moist. 13. _Cataracta_ is an opacity of the crystalline lens of the eye. It is a disease of light-coloured eyes, as the gutta serena is of dark ones. On cutting off with scissars the cornea of a calf's eye, and holding it in the palm of one's hand, so as to gain a proper light, the artery, which supplies nutriment to the crystalline humour, is easily and beautifully seen; as it rises from the centre of the optic nerve through the vitreous humour to the crystalline. It is this point, where the artery enters the eye through the cineritious part of the optic nerve, (which is in part near the middle of the nerve,) which is without sensibility to light; as is shewn by fixing three papers, each of them about half an inch in diameter, against a wall about a foot distant from each other, about the height of the eye; and then looking at the middle one, with one eye, and retreating till you lose sight of one of the external papers. Now as the animal grows older, the artery becomes less visible, and perhaps carries only a transparent fluid, and at length in some subjects I suppose ceases to be pervious; then it follows, that the crystalline lens, losing some fluid, and gaining none, becomes dry, and in consequence opake; for the same reason, that wet or oiled paper is more transparent than when it is dry, as explained in Class I. 1. 4. 1. The want of moisture in the cornea of old people, when the exhalation becomes greater than the supply, is the cause of its want of transparency; and which like the crystalline gains rather a milky opacity. The same analogy may be used to explain the whiteness of the hair of old people, which loses its pellucidity along with its moisture. See Class I. 2. 2. 11. M. M. Small electric shocks through the eye. A quarter of a grain of corrosive sublimate of mercury dissolved in brandy, or taken in a pill, twice a day for six weeks. Couching by depression, or by extraction. The former of these operations is much to be preferred to the latter, though the latter is at this time so fashionable, that a surgeon is almost compelled to use it, lest he should not be thought an expert operator. For depressing the cataract is attended with no pain, no danger, no confinement, and may be as readily repeated, if the crystalline should rise again to the centre of the eye. The extraction of the cataract is attended with considerable pain, with long confinement, generally with fever, always with inflammation, and frequently with irreparable injury to the iris, and consequent danger to the whole eye. Yet has this operation of extraction been trumpeted into universal fashion for no other reason but because it is difficult to perform, and therefore keeps the business in the hands of a few empyrics, who receive larger rewards, regardless of the hazard, which is encountered by the flattered patient. A friend of mine returned yesterday from London after an absence of many weeks; he had a cataract in a proper state for the operation, and in spite of my earnest exhortation to the contrary, was prevailed upon to have it extracted rather than depressed. He was confined to his bed three weeks after the operation, and is now returned with the iris adhering on one side so as to make an oblong aperture; and which is nearly, if not totally, without contraction, and thus greatly impedes the little vision, which he possesses. Whereas I saw some patients couched by depression many years ago by a then celebrated empyric, Chevalier Taylor, who were not confined above a day or two, that the eye might gradually be accustomed to light, and who saw as well as by extraction, perhaps better, without either pain, or inflammation, or any hazard of losing the eye. As the inflammation of the iris is probably owing to forcing the crystalline through the aperture of it in the operation of extracting it, could it not be done more safely by making the opening behind the iris and ciliary process into the vitreous humour? but the operation would still be more painful, more dangerous, and not more useful than that by depressing it. 14. _Innutritio ossium._ Innutrition of the bones. Not only the blood effused in vibices and petechiæ, or from bruises, as well as the blood and new vessels in inflamed parts, are reabsorbed by the increased action of the lymphatics; but the harder materials, which constitute the fangs of the first set of teeth, and the ends of exfoliating bones, and sometimes the matter of chalk-stones in the gout, the coagulable lymph, which is deposited on the lungs, or on the muscles after inflammation of those parts, and which frequently produces difficulty of breathing, and the pains of chronic rheumatism, and lastly the earthy part of the living bones are dissolved and absorbed by the increased actions of this system of vessels. See Sect. XXXIII. 3. 1. The earthy part of bones in this disease of the innutrition of them seems to suffer a solution, and reabsorption; while the secerning vessels do not supply a sufficient quantity of calcareous earth and phosphoric acid, which constitute the substance of bones. As calcareous earth abounds every where, is the want of phosphoric acid the remote cause? One cause of this malady is given in the Philosophic Transactions, where the patient had been accustomed to drink large quantities of vinegar. Two cases are described by Mr. Gouch. In one case, which I saw, a considerable quantity of calcareous earth, and afterwards of bone-ashes, and of decoction of madder, and also of sublimate of mercury, were given without effect. All the bones became soft, many of them broke, and the patient seemed to die from the want of being able to distend her chest owing to the softness of the ribs. M. M. Salt of urine, called sal microcosmicum, phosphorated soda. Calcined hartshorn. Bone-ashes. Hard or petrifying water, as that of Matlock, or such as is found in all limestone or marly countries. The calcareous earth in these waters might possibly be carried to the bones, as madder is known to colour them. Warm bath. Volatile or fixed alcali as a lotion on the spine, or essential oils. The innutrition of the bones is often first to be perceived by the difficulty of breathing and palpitation of the heart on walking a little faster than usual, which I suppose is owing to the softness of the ends of the ribs adjoining to the sternum; on which account they do not perfectly distend the chest, when they are raised by the pectoral and intercostal muscles with greater force than usual. After this the spine becomes curved both by the softness of its vertebræ, and for the purpose of making room for the disturbed heart. See Species 16 of this genus. As these patients are pale and weak, there would seem to be a deficiency of oxygene in their blood, and in consequence a deficiency of phosphoric acid; which is probably produced by oxygene in the act of respiration. Mr. Bonhome in the Chemical Annals, August, 1793, supposes the rickets to arise from the prevalence of vegetable or acetous acid, which is known to soften bones out of the body. Mr. Dettaen seems to have espoused a similar opinion, and both of them in consequence give alcalies and testacea. If this theory was just, the soft bones of such patients should shew evident marks of such acidity after death; which I believe has not been observed. Nor is it analogous to other animal facts, that nutritious fluids secreted by the finest vessels of the body should be so little animalized, as to retain acetous or vegetable acidity. The success attending the following case in so short a time as a fortnight I ascribed principally to the use of the warm bath; in which the patient continued for full half an hour every night, in the degree of heat, which was most grateful to her sensation, which might be I suppose about 94. Miss ----, about ten years of age, and very tall and thin, has laboured under palpitation of her heart, and difficult breathing on the least exercise, with occasional violent dry cough, for a year or more, with dry lips, little appetite either for food or drink, and dry skin, with cold extremities. She has at times been occasionally worse, and been relieved in some degree by the bark. She began to bend forwards, and to lift up her shoulders. The former seemed owing to a beginning curvature of the spine, the latter was probably caused to facilitate her difficult respiration. M. M. She used the warm bath, as above related; which by its warmth might increase the irritability of the smallest series of vessels, and by supplying more moisture to the blood might probably tend to carry further the materials, which form calcareous or bony particles, or to convey them in more dilute solution. She took twice a day twenty grains of extract of bark, twenty grains of soda phosphorata, and ten grams of chalk, and ten of calcined hartshorn mixed into a powder with ten drops of laudanum; with flesh food both to dinner and supper; and port wine and water instead of the small beer, she had been accustomed to; she lay on a sofa frequently in a day, and occasionally used a neck-swing. 15. _Rachitis._ Rickets. The head is large, protuberant chiefly on the forepart. The smaller joints are swelled; the ribs depressed; the belly tumid, with other parts emaciated. This disease from the innutrition or softness of the bones arose about two centuries ago; seems to have been half a century in an increasing or spreading state; continued about half a century at its height, or greatest diffusion; and is now nearly vanished: which gives reason to hope, that the small-pox, measles, and venereal disease, which are all of modern production, and have already become milder, may in process of time vanish from the earth, and perhaps be succeeded by new ones! See the preceding species. 16. _Spinæ distortio._ Distortion of the spine is another disease originating from the innutrition or softness of the bones. I once saw a child about six years old with palpitation of heart, and quickness of respiration, which began to have a curvature of the spine; I then doubted, whether the palpitation and quick respiration were the cause or consequence of the curvature of the spine; suspecting either that nature had bent the spine outwards to give room to the enlarged heart; or that the malformation of the chest had compressed and impeded the movements of the heart. But a few weeks ago on attending a young lady about ten years old, whose spine had lately began to be distorted, with very great difficulty and quickness of respiration, and alarming palpitation of the heart, I convinced myself, that the palpitation and difficult respiration were the effect of the change of the cavity of the chest from the distortion of the spine; and that the whole was therefore a disease of the innutrition or softness of the bones. For on directing her to lie down much in the day, and to take the bark, the distortion became less, and the palpitation and quick respiration became less at the same time. After this observation a neck-swing was directed, and she took the bark, madder, and bone-ashes; and she continues to amend both in her shape and health. Delicate young ladies are very liable to become awry at many boarding schools. This is occasioned principally by their being obliged too long to preserve an erect attitude, by sitting on forms many hours together. To prevent this the school-seats should have either backs, on which they may occasionally rest themselves; or desks before them, on which they may occasionally lean. This is a thing of greater consequence than may appear to those, who have not attended to it. When the least tendency to become awry is observed, they should be advised to lie down on a bed or sofa for an hour in the middle of the day for many months; which generally prevents the increase of this deformity by taking off for a time the pressure on the spine of the back, and it at the same time tends to make them grow taller. Young persons, when nicely measured, are found to be half an inch higher in a morning than at night; as is well known to those, who inlist very young men for soldiers. This is owing to the cartilages between the bones of the back becoming compressed by the weight of the head and shoulders on them during the day. It is the same pressure which produces curvatures and distortions of the spine in growing children, where the bones are softer than usual; and which may thus be relieved by an horizontal posture for an hour in the middle of the day, or by being frequently allowed to lean on a chair, or to play on the ground on a carpet. Young ladies should also be directed, where two sleep in a bed, to change every night, or every week, their sides of the bed; which will prevent their tendency to sleep always on the same side; which is not only liable to produce crookedness, but also to occasion diseases by the internal parts being so long kept in uniform contact as to grow together. For the same reason they should not be allowed to sit always on the same side of the fire or window, because they will then be inclined too frequently to bend themselves to one side. Another great cause of injury to the shape of young ladies is from the pressure of stays, or other tight bandages, which at the same time cause other diseases by changing the form or situation of the internal parts. If a hard part of the stays, even a knot of the thread, with which they are sewed together, is pressed hard upon one side more than the other, the child bends from the side most painful, and thus occasions a curvature of the spine. To counteract this effect such stays, as have fewest hard parts, and especially such as can be daily or weekly turned, are preferable to others. [Illustration] Where frequent lying down on a sofa in the day-time, and swinging frequently for a short time by the hands or head, with loose dress, do not relieve a beginning distortion of the back; recourse may be had to a chair with stuffed moveable arms for the purpose of suspending the weight of the body by cushions under the arm-pits, like resting on crutches, or like the leading strings of infants. From the top of the back of the same chair a curved steel bar may also project to suspend the body occasionally, or in part by the head, like the swing above mentioned. The use of this chair is more efficacious in straightening the spine, than simply lying down horizontally; as it not only takes off the pressure of the head and shoulders from the spine, but at the same time the inferior parts of the body contribute to draw the spine straight by their weight; or lastly, recourse may be had to a spinal machine first described in the Memoires of the academy of surgery in Paris, Vol. III. p. 600, by M. Le Vacher, and since made by Mr. Jones, at N^o 6, North-street, Tottenham-court Road, London, which suspends the head, and places the weight of it on the hips. This machine is capable of improvement by joints in the bar at the back of it, to permit the body to bend forwards without diminishing the extension of the spine. The objections of this machine of M. Vacher, which is made by Mr. Jones, are first, that it is worn in the day-time, and has a very unsightly appearance. Mr. Jones has endeavoured to remedy this, by taking away the curved bar over the head, and substituting in its place a forked bar, rising up behind each ear, with webs fastened to it, which pass under the chin and occiput. But this is not an improvement, but a deterioration of M. Vacher's machine, as it prevents the head from turning with facility to either side. Another objection is, that its being worn, when the muscles of the back are in action, it is rather calculated to prevent the curvature of the spine from becoming greater, than to extend the spine, and diminish its curvature. [Illustration] For this latter purpose I have made a steel bow, as described in the annexed plate, which receives the head longitudinally from the forehead to the occiput; having a fork furnished with a web to sustain the chin, and another to sustain the occiput. The summit of the bow is fixed by a swivel to the board going behind the head of the bed above the pillow. The bed is to be inclined from the head to the feet about twelve or sixteen inches. Hence the patient would be constantly sliding down during sleep, unless supported by this bow, with webbed forks, covered also with fur, placed beneath the chin, and beneath the occiput. There are also proper webs lined with fur for the hands to take hold off occasionally, and also to go under the arms. By these means I should hope great advantage from gradually extending the spine during the inactivity of the muscles of the back; and that it may be done without disturbing the sleep of the patient, and if this should happen, the bow is made to open by a joint at the summit of it, so as to be instantly disengaged from the neck by the hand of the wearer. This bow I have not yet had opportunity to make use of, but it may be had from Mr. Harrison, whitesmith, Bridge-gate, Derby. It will be from hence easily perceived, that all other methods of confining or directing the growth of young people should be used with great skill; such as back-boards, or bandages, or stocks for the feet; and that their application should not be continued too long at a time, lest worse consequences should ensue, than the deformity they were designed to remove. To this may be added, that the stiff erect attitude taught by some modern dancing masters does not contribute to the grace of person, but rather militates against it; as is well seen in one of the prints in Hogarth's Analysis of Beauty; and is exemplifyed by the easy grace of some of the ancient statues, as of the Venus de Medici, and the Antinous, and in the works of some modern artists, as in a beautiful print of Hebe feeding an Eagle, painted by Hamilton, and engraved by Eginton, and many of the figures of Angelica Kauffman. Where the bone of one of the vertebræ of the back has been swelled on both sides of it, so as to become protuberant, issues near the swelled part have been found of great service, as mentioned in Species 18 of this genus. This has induced me to propose in curvatures of the spine, to put an issue on the outside of the curve, where it could be certainly ascertained, as the bones on the convex side of the curve must be enlarged; in one case I thought this of service, and recommend the further trial of it. In the tendency to curvature of the spine, whatever strengthens the general constitution is of service; as the use of the cold bath in the summer months. This however requires some restriction both in respect to the degree of coldness of the bath, the time of continuing in it, and the season of the year. Common springs, which are of forty-eight degrees of heat, are too cold for tender constitutions, whether of children or adults, and frequently do them great and irreparable injury. The coldness of river water in the summer months, which is about sixty-eight degrees, or that of Matlock, which is about sixty-eight, or of Buxton, which is eighty-two, are much to be preferred. The time of continuing in the bath should be but a minute or two, or not so long as to occasion a trembling of the limbs from cold. In respect to the season of the year, delicate children should certainly only bathe in the summer months; as the going frequently into the cold air in winter will answer all the purposes of the cold bath. 17. _Claudicatio coxaria._ Lameness of the hip. A nodding of the thigh-bone is said to be produced in feeble children by the softness of the neck or upper part of that bone beneath the cartilage; which is naturally bent, and in this disease bends more downwards, or nods, by the pressure of the body; and thus renders one leg apparently shorter than the other. In other cases the end of the bone is protruded out of its socket, by inflammation or enlargement of the cartilages or ligaments of the joint, so that it rests on some part of the edge of the acetabulum, which in time becomes filled up. When the legs are straight, as in standing erect, there is no verticillary motion in the knee-joint; all the motion then in turning out the toes further than nature designed, must be obtained by straining in some degree this head of the thigh-bone, or the acetabulum, or cavity, in which it moves. This has induced me to believe, that this misfortune of the nodding of the head by the bone, or partial dislocation of it, by which one leg becomes shorter than the other, is sometimes occasioned by making very young children stand in what are called stocks; that is with their heels together, and their toes quite out. Whence the socket of the thigh-bone becomes inflamed and painful, or the neck of the bone is bent downward and outwards. In this case there is no expectation of recovering the straightness of the end of the bone; but these patients are liable to another misfortune, that is, to acquire afterwards a distortion of the spine; for as one leg is shorter than the other, they sink on that side, and in consequence bend the upper part of their bodies, as their shoulders, the contrary way, to balance themselves; and then again the neck is bent back again towards the lame side, to preserve the head perpendicular; and thus the figure becomes quite distorted like the letter S, owing originally to the deficiency of the length of one limb. The only way to prevent this curvature of the spine is for the child to wear a high-heeled shoe or patten on the lame foot, so as to support that side on the same level with the other, and thus to prevent a greater deformity. I have this day seen a young lady about twelve, who does not limp or waddle in walking; but nevertheless, when she stands or sits, she sinks down towards her right side, and turns out that toe more than the other. Hence, both as she sits and stands, she bends her body to the right; whence her head would hang a little over her right shoulder; but to replace this perpendicularly, she lifts up her left shoulder and contracts the muscles on that side of the neck; which are therefore become thicker and stronger by their continued action; but there is not yet any very perceptible distortion of the spine. As her right toe is turned outward rather more than natural, this shews the disease to be in the hip-joint; because, when the limb is stretched out, the toe cannot turn horizontally in the least without moving the end of the thigh-bone; although when the knee is bent, the toe can be turned through one third or half of a circle by the rotation of the tibia and fibula of the leg round each other. Hence if children are set in stocks with their heels touching each other as they sit, and are then made to rise up, till they stand erect, the socket or head of the thigh-bone becomes injured, especially in those children, whose bones are soft; and a shortness of that limb succeeds either by the bending of the neck of the thigh-bone, or by its getting out of the acetabulum; and a consequent rising of one shoulder, and a curvature of the spine is produced from so distant a cause. M. M. An elastic cushion made of curled hair should be placed under the affected hip, whenever she sits; or should be fitted to the part by means of drawers, so that she cannot avoid sitting on it. A neck-swing, and lying down in the day, should be occasionally used to prevent or remove any curvature of the spine. The rest as in Species 13 and 15 of this genus. 18. _Spina protuberans._ Protuberant spine. One of the bones of the spine swells, and rises above the rest. This is not an uncommon disease, and belongs to the innutrition of the bones, as the bone must become soft before it swells; which softness is owing to defect of the secretion of phosphorated calcareous earth. The swelling of the bone compresses a part of the brain, called the spinal marrow, within the cavity of the back-bones; and in consequence the lower limbs become paralytic, attended sometimes with difficulty of emptying the bladder and rectum. M. M. Issues put on each side of the prominent bone are of great effect, I suppose, by their stimulus; which excites into action more of the sensorial powers of irritation and sensation, and thus gives greater activity to the vascular system in their vicinity. The methods recommended in distortion of the spine are also to be attended to. 19. _Spina bifida._ Divided spine, called also Hydrorachitis, as well as the Hydrocephalus externus, are probably owing in part to a defect of ossification of the spine and cranium; and that the collection of fluid beneath them may originate from the general debility of the system; which affects both the secerning, and absorbent vessels. A curious circumstance, which is affirmed to attend the spina bifida, is, that on compressing the tumor with the hand gently, the whole brain becomes affected, and the patient falls asleep. I suppose the same must happen on compressing the hydrocephalus externus? See Sect. XVIII. 20. 20. _Ossis palati defectus._ A defect of the bone of the palate, which frequently accompanies a division of the upper lip, occurs before nativity; and is owing to the deficient action of the secerning system, from whence the extremities are not completed. From a similar cause I have seen the point of the tongue deficient, and one joint of the two least fingers, and of the two least toes, in the same infant; who was otherwise a fine girl. See Sect. XXXIX. 4. 4. The operation for the hare-lip is described by many surgical writers; but there is a person in London, who makes very ingenious artificial palates; which prevents that defect of speech, which attends this malformation. This factitious palate consists of a thin plate of silver of the shape and form of the roof of the mouth; from the front edge to the back edge of this silver plate four or five holes are made in a straight line large enough for a needle to pass through them; on the back of it is then sewed a piece of sponge; which when expanded with moisture is nearly as large as the silver plate. This sponge is slipped through the division of the bone of the palate, so as to lie above it, while the silver plate covers the aperture beneath, and is suspended by the expanding sponge. This is removed every night and washed, and returned into its place in the morning; on this account it is convenient to have five or six of them, for the sake of cleanliness. I have been more particular in describing this invention, as I do not know the name, or place of residence, of the maker. * * * * * ORDO II. _Decreased Irritation._ GENUS III. _The Decreased Action of the Absorbent System._ Some decrease of heat attends these diseases, though in a less degree than those of the last genus, because the absorbent system of glands do not generate so much heat in their healthy state of action as the secerning system of glands, as explained in Class I. 1. 3. SPECIES. 1. _Mucus faucium frigidus._ Cold mucus from the throat. Much mucus, of rather a saline taste, and less inspissated than usual, is evacuated from the fauces by hawking, owing to the deficient absorption of the thinner parts of it. This becomes a habit in some elderly people, who are continually spitting it out of their mouths; and has probably been brought on by taking snuff, or smoking tobacco; which by frequently stimulating the fauces have at length rendered the absorbent vessels less excitable by the natural stimulus of the saline part of the secretion, which ought to be reabsorbed, as soon as secreted. M. M. A few grains of powder of bark frequently put into the mouth, and gradually diffused over the fauces. A gargle of barley water. 2. _Sudor frigidus._ The cold dampness of the hands of some people is caused by the deficient absorption of perspirable matter; the clammy or viscid feel of it is owing to the mucous part being left upon the skin. The coldness is produced both by the decreased action of the absorbent system, and by the evaporation of a greater quantity of the perspirable matter into the air, which ought to have been absorbed. M. M. Wash the hands in lime water, or with a small quantity of volatile alcali in water. 3. _Catarrhus frigidus._ The thin discharge from the nostrils in cold weather. The absorbent vessels become torpid by the diminution of external heat, sooner than the secerning ones, which are longer kept warm by the circulating blood, from which they select the fluid they secrete; whereas the absorbent vessels of the nostrils drink up their fluids, namely the thin and saline part of the mucus, after it has been cooled by the atmosphere. Hence the absorbents ceasing to act, and the secerning vessels continuing some time longer to pour out the mucus, a copious thin discharge is produced, which trickles down the nostrils in cold weather. This discharge is so acrid as to inflame the upper lip; which is owing to the neutral salts, with which it abounds, not being reabsorbed; so the tears in the fistula lacrymalis inflame the cheek. See Class I. 1. 2. 7. 4. _Expectoratio frigida._ Cold expectoration. Where the pulmonary absorption is deficient, an habitual cough is produced, and a frequent expectoration of thin saline mucus; as is often seen in old enfeebled people. Though the stimulus of the saline fluid, which attends all secretions, is not sufficient to excite the languid absorbent vessels to imbibe it; yet this saline part, together with the increased quantity of the whole of the secreted mucus, stimulates the branches of the bronchia, so as to induce an almost incessant cough to discharge it from the lungs. A single grain of opium, or any other stimulant drug, as a wine-posset with spirit of hartshorn, will cure this cold cough, and the cold catarrh of the preceding article, like a charm, by stimulating the torpid mouths of the absorbents into action. Which has given rise to an indiscriminate and frequently pernicious use of the warm regimen in coughs and catarrhs of the warm or inflammatory kind, to the great injury of many. M. M. Half a grain of opium night and morning promotes the absorption of the more fluid and saline parts, and in consequence thickens the mucus, and abates its acrimony. Warm diluent drink, wine-whey, with volatile alcali. 5. _Urina uberior pallida._ On being exposed naked to cold air, or sprinkled with cold water, a quantity of pale urine is soon discharged; for the absorbents of the bladder become torpid by their sympathy with those of the skin; which are rendered quiescent by the diminution of external heat; but the kidnies continue to secrete the urine, and as no part of it is absorbed, it becomes copious and pale. This happens from a similar cause in cold fits of agues; and in less degree to many debilitated constitutions, whose extremities are generally cold and pale. The great quantity of limpid water in hysteric cases, and in diabætes, belongs to Class I. 3. 1. 10. I. 3. 2. 6. M. M. Tincture of cantharides, opium, alum, sorbentia. Flannel shirt in cold weather. Animal food. Beer. Wine. Friction. Exercise. Fire. 6. _Diarrhoea frigida._ Liquid stools are produced by exposing the body naked to cold air, or sprinkling it with cold water, for the same reason as the last article. But this disease is sometimes of a dangerous nature; the intestinal absorption being so impaired, that the aliment is said to come away undiminished in quantity, and almost unchanged by the powers of digestion, and is then called lientery. The mucus of the rectum sometimes comes away like pellucid hartshorn jelly, and liquefies by heat like that, towards the end of inirritative fevers, which is owing to the thinner part of the mucus not being absorbed, and thus resembles the catarrh of some old people. M. M. Opium, campechy wood, armenian bole. Blister. Flannel shirt in cold weather. Clysters with opium. Friction on the bowels morning and night. Equitation twice a day. 7. _Fluor albus frigidus._ Cold fluor albus. In weak constitutions, where this discharge is pellucid and thin, it must proceed from want of absorption of the mucous membrane of the vagina, or uterus, and not from an increased secretion. This I suspect to be the most frequent kind of fluor albus; the former one described at Class I. 1. 2. 11. attends menstruation, or is a discharge instead of it, and thus resembles the venereal orgasm of female quadrupeds. The discharge in this latter kind being more saline, is liable to excoriate the part, and thus produce smarting in making water; in its great degree it is difficult to cure. M. M. Increase the evacuation by stool and by perspiration, by taking rhubarb every night, about six or ten grains with one grain of opium for some months. Flannel shirt in winter. Balsam copaiva. Gum kino, bitters, chalybeates, friction over the whole skin with flannel morning and night. Partial cold bath, by sprinkling the loins and thighs, or sponging them with cold water. Mucilage, as isinglass boiled in milk; blanc mange, hartshorn jelly, are recommended by some. Tincture of cantharides sometimes seems of service given from ten to twenty drops or more, three or four times a day. A large plaster of burgundy pitch and armenian bole, so as to cover the loins and lower part of the belly, is said to have sometimes succeeded by increasing absorption by its compression in the manner of a bandage. A solution of metallic salts, as white vitriol, sixty grains to a pint; or an infusion of oak-bark may be injected into the vagina. Cold bath. 8. _Gonorrhoea frigida._ Cold gleet. Where the gleet is thin and pellucid, it must arise from the want of absorption of the membranes of the urethra, rather than from an increased secretion from them. This I suppose to be a more common disease than that mentioned at Class I. 1. 2. 10. M. M. Metallic injections, partial cold bath, internal method as in the fluor albus above described. Balsam of copaiva. Tincture of cantharides. 9. _Hepatis tumor._ The liver becomes enlarged from defect of the absorption of mucus from its cells, as in anasarca, especially in feeble children; at the same time less bile is secreted from the torpid circulation in the vena portæ. And as the absorbents, which resume the thinner parts of the bile from the gall-bladder and hepatic ducts, are also torpid or quiescent, the bile is more dilute, as well as in less quantity. From the obstruction of the passage of the blood through the compressed vena porta these patients have tumid bellies, and pale bloated countenances; their paleness is probably owing to the deficiency of the quantity of red globules in the blood in consequence of the inert state of the bile. These symptoms in children are generally attended with worms, the dilute bile and the weak digestion not destroying them. In sleep I have seen fleuke-worms in the gall-ducts themselves among the dilute bile; which gall-ducts they eat through, and then produce ulcers, and the hectic fever, called the rot. See Class I. 1. 4. 10. and Article IV. 2. 6. M. M. After a calomel purge, crude iron-filings are specific in this disease in children, and the worms are destroyed by the returning acrimony and quantity of the bile. A blister on the region of the liver. Sorbentia, as worm-seed, santonicum. Columbo. Bark. 10. _Chlorosis._ When the defect of the due action of both the absorbent and secerning vessels of the liver affects women, and is attended with obstruction of the catamenia, it is called chlorosis; and is cured by the exhibition of steel, which restores by its specific stimulus the absorbent power of the liver; and the menstruation, which was obstructed in consequence of debility, recurs. Indigestion, owing to torpor of the stomach, and a consequent too great acidity of its contents, attend this disease; whence a desire of eating chalk, or marl. Sometimes a great quantity of pale urine is discharged in a morning, which is owing to the inaction of the absorbents, which are distributed on the neck of the bladder, during sleep. The swelling of the ankles, which frequently attends chlorosis, is another effect of deficient action of the absorbent system; and the pale countenance is occasioned by the deficient quantity of red globules of blood, caused by the deficient quantity or acrimony of the bile, and consequent weakness of the circulation. The pulse is so quick in some cases of chlorosis, that, when attended with an accidental cough, it may be mistaken for pulmonary consumption. This quick pulse is owing to the debility of the heart from the want of stimulus occasioned by the deficiency of the quantity, and acrimony of the blood. M. M. Steel. Bitters. Constant moderate exercise. Friction with flannel all over the body and limbs night and morning. Rhubarb five grains, opium half a grain, every night. Flesh diet, with small beer, or wine and water. The disease continues some months, but at length subsides by the treatment above described. A bath of about eighty degrees, as Buxton Bath, is of service; a colder bath may do great injury. 11. _Hydrocele._ Dropsy of the vagina testis. Dropsies have been divided into the incysted and the diffused, meaning those of the cellular membrane, the cells of which communicate with each other like a sponge, and those of any other cavity of the body. The collections of mucous fluids in the various cells and cavities of the body arise from the torpor of the absorbent vessels of those parts. It is probable, that in dropsies attended with great thirst the cutaneous absorbents become paralytic first; and then from the great thirst, which is thus occasioned by the want of atmospheric moisture, the absorption of the fat ensues; as in fevers attended with great thirst, the fat is quickly taken up. See Obesitas I. 2. 3. 17. Some have believed, that the cellular and adipose membranes are different ones; as no fat is ever deposited in the eye-lids or scrotum, both which places are very liable to be distended with the mucilaginous fluid of the anasarca, and with air in Emphysema. Sometimes a gradual absorption of the accumulated fluid takes place, and the thinner parts being taken up, there remains a more viscid fluid, or almost a solid in the part, as in some swelled legs, which can not easily be indented by the pressure of the finger, and are called scorbutic. Sometimes the paralysis of the absorbents is completely removed, and the whole is again taken up into the circulation. The Hydrocele is known by a tumor of the scrotum, which is without pain, gradually produced, with fluctuation, and a degree of pellucidity, when a candle is held behind it; it is the most simple incysted dropsy, as it is not in general complicated with other diseases, as ascites with schirrous liver, and hydrocephalus internus, with general debility. The cure of this disease is effected by different ways; it consists in discharging the water by an external aperture; and by so far inflaming the cyst and testicle, that they afterwards grow together, and thus prevent in future any secretion or effusion of mucus; the disease is thus cured, not by the revivescence of the absorbent power of the lymphatics, but by the prevention of secretion by the adhesion of the vagina to the testis. This I believe is performed with less pain, and is more certainly manageable by tapping, or discharging the fluid by means of a trocar, and after the evacuation of it to fill the cyst with a mixture of wine and water for a few minutes till the necessary degree of stimulus is produced, and then to withdraw it; as recommended by Mr. Earle. See also Medical Commentaries by Dr. Duncan, for 1793. 12. _Hydrocephalus internus_, or dropsy of the ventricles of the brain, is fatal to many children, and some adults. When this disease is less in quantity, it probably produces a fever, termed a nervous fever, and which is sometimes called a worm fever, according to the opinion of Dr. Gilchrist, in the Scots Medical essays. This fever is attended with great inirritability, as appears from the dilated pupils of the eyes, in which it corresponds with the dropsy of the brain. And the latter disease has its paroxysms of quick pulse, and in that respect corresponds with other fevers with inirritability. The hydrocephalus internus is distinguished from apoplexy by its being attended with fever, and from nervous fever by the paroxysms being very irregular, with perfect intermissions many times in a day. In nervous fever the pain of the head generally affects the middle of the forehead; in hydrocephalus internus it is generally on one side of the head. One of the earliest criterions is the patient being uneasy on raising his head from the pillow, and wishing to lie down again immediately; which I suppose is owing to the pressure of the water on the larger trunks of the blood-vessels entering the cavity being more intolerable than on the smaller ones; for if the larger trunks are compressed, it must inconvenience the branches also; but if some of the small branches are compressed only, the trunks are not so immediately incommoded. Blisters on the head, and mercurial ointment externally, with calomel internally, are principally recommended in this fatal disease. When the patient cannot bear to be raised up in bed without great uneasiness, it is a bad symptom. So I believe is deafness, which is commonly mistaken for stupor. See Class I. 2. 5. 6. And when the dilatation of the pupil of either eye, or the squinting is very apparent, or the pupils of both eyes much dilated, it is generally fatal. As by stimulating one branch of lymphatics into inverted motion, another branch is liable to absorb its fluid more hastily; suppose strong errhines, as common tobacco snuff to children, or one grain of turpeth mineral, (Hydrargyrus vitriolatus), mixed with ten or fifteen grains of sugar, was gradually blown up the nostrils? See Class I. 3. 2. 1. I have tried common snuff upon two children in this disease; one could not be made to sneeze, and the other was too near death to receive advantage. When the mercurial preparations have produced salivation, I believe they may have been of service, but I doubt their good effect otherwise. In one child I tried the tincture of Digitalis; but it was given with too timid a hand, and too late in the disease, to determine its effects. See Sect. XXIX. 5. 9. As all the above remedies generally fail of success, I think frequent, almost hourly, shocks of electricity from very small charges might be passed through the head in all directions with probability of good event. And the use of the trephine, where the affected side can be distinguished. See Strabismus, Class I. 2. 5. 4. When one eye is affected, does the disease exist in the ventricule of that side? 13. _Ascites._ The dropsy of the cavity of the abdomen is known by a tense swelling of the belly; which does not sound on being struck like the tympany; and in which a fluctuation can be readily perceived by applying one hand expanded on one side, and striking the tumour on the other. Effusions of water into large cavities, as into that of the abdomen or thorax, or into the ventricules of the brain or pericardium, are more difficult to be reabsorbed, than the effusion of fluids into the cellular membrane; because one part of this extensive sponge-like system of cells, which connects all the solid parts of the body, may have its power of absorption impaired, at the same time that some other part of it may still retain that power, or perhaps possess it in an increased degree; and as all these cells communicate with each other, the fluid, which abounds in one part of it, can be transferred to another, and thus be reabsorbed into the circulation. In the ascites, cream of tartar has sometimes been attended with success; a dram or two drams are given every hour in a morning till it operates, and is to be repeated for several days; but the operation of tapping is generally applied to at last. Dr. Sims, in the Memoirs of the Medical Society of London, Vol. III. has lately proposed, what he believes to be a more successful method of performing this operation, by making a puncture with a lancet in the scar of the navel, and leaving it to discharge itself gradually for several days, without introducing a canula, which he thinks injurious both on account of the too sudden emission of the fluid, and the danger of wounding or stimulating the viscera. This operation I have twice known performed with less inconvenience, and I believe with more benefit to the patient, than the common method. After the patient has been tapped, some have tried injections into the cavity of the abdomen, but hitherto I believe with ill event. Nor are experiments of this kind very promising of success. First because the patients are generally much debilitated, most frequently by spirituous potation, and have generally a disease of the liver, or of other viscera. And secondly, because the quantity of inflammation, necessary to prevent future secretion of mucus into the cavity of the abdomen, by uniting the peritoneum with the intestines or mesentery, as happens in the cure of the hydrocele, would I suppose generally destroy the patient, either immediately, or by the consequence of such adhesions. This however is not the case in respect to the dropsy of the ovarium, or in the hydrocele. 14. _Hydrops thoracis._ The dropsy of the chest commences with loss of flesh, cold extremities, pale countenance, high coloured urine in small quantity, and general debility, like many other dropsies. The patient next complains of numbness in the arms, especially when elevated, with pain and difficulty of swallowing, and an absolute impossibility of lying down for a few minutes, or with sudden starting from sleep, with great difficulty of breathing and palpitation of his heart. The numbness of the arms is probably owing more frequently to the increased action of the pectoral muscles in respiration, whence they are less at liberty to perform other offices, than to the connexion of nerves mentioned in Sect. XXIX. 5. 2. The difficulty of swallowing is owing to the compression of the oesophagus by the lymph in the chest; and the impossibility of breathing in an horizontal posture originates from this, that if any parts of the lungs must be rendered useless, the inability of the extremities of them must be less inconvenient to respiration; since if the upper parts or larger trunks of the air-vessels should be rendered useless by the compression of the accumulated lymph, the air could not gain admittance to the other parts, and the animal must immediately perish. If the pericardium is the principal seat of the disease, the pulse is quick and irregular. If only the cavity of the thorax is hydropic, the pulse is not quick nor irregular. If one side is more affected than the other, the patient leans most that way, and has more numbness in that arm. The hydrops thoracis is distinguished from the anasarca pulmonum, as the patient in the former cannot lie down half a minute; in the latter the difficulty of breathing, which occasions him to rise up, comes on more gradually; as the transition of the lymph in the cellular membranes from one part to another of it is slower, than that of the effused lymph in the cavity of the chest. The hydrops thoracis is often complicated with fits of convulsive breathing; and then it produces a disease for the time very similar to the common periodic asthma, which is perhaps owing to a temporary anasarca of the lungs; or to an impaired venous absorption in them. These exacerbations of difficult breathing are attended with cold extremities, cold breath, cold tongue, upright posture with the mouth open, and a desire of cold air, and a quick, weak, intermittent pulse, and contracted hands. These exacerbations recur sometimes every two or three hours, and are relieved by opium, a grain every hour for two or three doses, with ether about a dram in cold water; and seem to be a convulsion of the muscles of respiration induced by the pain of the dyspnea. As in Class III. 1. 1. 9. M. M. A grain of dried squill, and a quarter of a grain of blue vitriol every hour for six or eight hours, unless it vomit or purge. A grain of opium. Blisters. Calomel three grains every third day, with infusion of senna. Bark. Chalybeates. Puncture in the side. Can the fluctuation in the chest be heard by applying the ear to the side, as Hippocrates asserts? Can it be felt by the hand or by the patient before the disease is too great to admit of cure by the paracentesis? Does this dropsy of the chest often come on after peripneumony? Is it ever cured by making the patient sick by tincture of digitalis? Could it be cured, if on one side only, by the operation of puncture between the ribs, and afterwards by inflaming the cavity by the admission of air for a time, like the cure of the hydrocele; the pleura afterwards adhering wholly to that lobe of the lungs, so as to prevent any future effusion of mucus? 15. _Hydrops ovarii._ Dropsy of the ovary is another incysted dropsy, which seldom admits of cure. It is distinguished from ascites by the tumour and pain, especially at the beginning, occupying one side, and the fluctuation being less distinctly perceptible. When it happens to young subjects it is less liable to be mistaken for ascites. It affects women of all ages, either married or virgins; and is produced by cold, fear, hunger, bad food, and other debilitating causes. I saw an elegant young lady, who was shortly to have been married to a sensible man, with great prospect of happiness; who, on being overturned in a chaise in the night, and obliged to walk two or three miles in wet, cold, and darkness, became much indisposed, and gradually afflicted with a swelling and pain on one side of the abdomen; which terminated in a dropsy of the ovary, and destroyed her in two or three years. Another young woman I recollect seeing, who was about seventeen, and being of the very inferior class of people, seemed to have been much weakened by the hardship of a cold floor, and little or no bed, with bad food; and who to these evils had to bear the unceasing obloquy of her neighbours, and the persecution of parish officers. The following is abstracted from a letter of my friend Mr. Power, surgeon, at Bosworth in Leicestershire, on examining the body of an elderly lady who died of this disease, March 29, 1793. "On opening the abdomen I found a large cyst attached to the left ovarium by an elastic neck as thick as the little finger, and so callous as not to admit of being separated by scissars without considerable difficulty. The substance of the cyst had an appearance much resembling the gravid uterus near the full period of gestation, and was as thick. It had no attachment to the peritonæum, or any of the viscera, except by the hard callous neck I have mentioned; so that the blood must with difficulty have been circulated through it for some time. Its texture was extremely tender, being easily perforated with the finger, was of a livid red colour, and evidently in a sphacelated state. It contained about two gallons of a fluid of the colour of port wine, without any greater tenacity. It has fallen to my lot to have opened two other patients, whose deaths were occasioned by incysted dropsy of the ovarium. In one of these the ovarium was much enlarged with eight or ten cysts on its surface, but there was no adhesion formed by any of the cysts to any other part; nor had the ovarium formed any adhesion with the peritonæum, though in a very diseased state. In the other the disease was more simple, being only one cyst, without any attachment but to the ovarium. "As the ovarium is a part not necessary to life, and dropsies of this kind are so generally fatal in the end, I think I shall be induced, notwithstanding the hazard attending wounds, which penetrate the cavity of the abdomen, to propose the extirpation of the diseased part in the first case, which occurs to me, in which I can with precision say, that the ovarium is the seat of the disease, and the patient in other respects tolerably healthy; as the cavity of the abdomen is often opened in other cases without bad consequences." An argument, which might further countenance the operation thus proposed by Mr. Power, might be taken from the disease frequently affecting young persons; from its being generally in these subjects local and primary; and not like the ascites, produced or accompanied with other diseased viscera; and lastly, as it is performed in adult quadrupeds, as old sows, with safety, though by awkward operators. 16. _Anasarca pulmonum._ The dropsy of the cellular membrane of the lungs is usually connected with that of the other parts of the system. As the cells of the whole cellular membrane communicate with each other, the mucaginous fluid, which remains in any part of it for want of due absorption, sinks down to the most depending cells; hence the legs swell, though the cause of the disease, the deficiency of absorption, may be in other parts of the system. The lungs however are an exception to this, since they are suspended in the cavity of the thorax, and have in consequence a depending part of their own. The anasarca of the lungs is known by the difficulty of respiration accompanied with swelled legs, and with a very irregular pulse. This last circumstance has generally been ascribed to a dropsy at the same time existing in the pericardium, but is more probably owing to the difficult passage of the blood through the lungs; because I found on dissection, in one instance, that the most irregular pulse, which I ever attended to, was owing to very extensive adhesions of the lungs; insomuch that one lobe intirely adhered to the pleura; and secondly, because this kind of dropsy of the lungs is so certainly removed for a time along with the anasarca of the limbs by the use of digitalis. This medicine, as well as emetic tartar, or squill, when given so as to produce sickness, or nausea, or perhaps even without producing either in any perceptible degree, by affecting the lymphatics of the stomach, so as either to invert their motion, or to weaken them, increases by reverse sympathy the action, and consequent absorbent power of these lymphatics, which open into the cellular membrane. But as those medicines seldom succeed in producing an absorption of those fluids, which stagnate in the larger cavities of the body, as in the abdomen, or chest, and do generally succeed in this difficulty of breathing with irregular pulse above described, I conclude that it is not owing to an effusion of lymph into the pericardium, but simply to an anasarca of the lungs. M. M. Digitalis. See Art. V. 2. 1. Tobacco. Squill. Emetic tartar (antimonium tartarizatum). Then Sorbentia. Chalybeates. Opium half a grain twice a day. Raisin wine and water, or other wine and water, is preferred to the spirit and water, which these patients have generally been accustomed to. The usual cause of anasarca is from a diseased liver, and hence it most frequently attends those, who have drank much fermented or spirituous liquors; but I suspect that there is another cause of anasarca, which originates from the brain; and which is more certainly fatal than that, which originates from a diseased liver. These patients, where the anasarca originates from, or commences in, the brain, have not other symptoms of diseased liver; have less difficulty of breathing at the beginning; and hold themselves more upright in their chair, and in walking. In this kind of dropsy I suspect the digitalis has less or no effect; as it particularly increases the absorption from the lungs. 17. _Obesitas._ Corpulency may be called an anasarca or dropsy of fat, since it must be owing to an analogous cause; that is, to the deficient absorption of fat compared to the quantity secreted into the cells which contain it. See Class II. 1. 1. 4. The method of getting free from too much fat without any injury to the constitution, consists, first, in putting on a proper bandage on the belly, so that it can be tightened or relaxed with ease, as a tightish under waistcoat, with a double row of buttons. This is to compress the bowels and increase their absorption, and it thus removes one principal cause of corpulency, which is the looseness of the skin. Secondly, he should omit one entire meal, as supper; by this long abstinence from food the absorbent system will act on the mucus and fat with greater energy. Thirdly, he should drink as little as he can with ease to his sensations; since, if the absorbents of the stomach and bowels supply the blood with much, or perhaps too much, aqueous fluid, the absorbents of the cellular membrane will act with less energy. Fourthly, he should use much salt or salted meat, which will increase the perspiration and make him thirsty; and if he bears this thirst, the absorption of his fat will be greatly increased, as appears in fevers and dropsies with thirst; this I believe to be more efficacious than soap. Fifthly, he may use aerated alcaline water for his drink, which may be supposed to render the fat more fluid,--or he may take soap in large quantities, which will be decomposed in the stomach. Sixthly, short rest, and constant exercise. 18. _Splenis tumor._ Swellings of the spleen, or in its vicinity, are frequently perceived by the hand in intermittents, which are called Ague-cakes, and seem owing to a deficiency of absorption in the affected part. Mr. Y----, a young man about twenty-five years of age, who lived intemperately, was seized with an obstinate intermittent, which had become a continued fever with strong pulse, attended with daily remission. A large hard tumour on the left side, on the region of the spleen, but extending much more downward, was so distinctly perceptible, that one seemed to get one's fingers under the edge of it, much like the feel of the brawn or shield on a boar's shoulder. He was repeatedly bled, and purged with calomel, had an emetic, and a blister on the part, without diminishing the tumour; after some time he took the Peruvian bark, and slight doses of chalybeates, and thus became free from the fever, and went to Bath for several weeks, but the tumour remained. This tumour I examined every four or five years for above thirty years. His countenance was pale, and towards the end of his life he suffered much from ulcers on his legs, and died about sixty, of general debility; like many others, who live intemperately in respect to the ingurgitation of fermented or spirituous liquors. As this tumour commenced in the cold fit of an intermittent fever, and was not attended with pain, and continued so long without endangering his life, there is reason to believe it was simply occasioned by deficient absorption, and not by more energetic action of the vessels which constitute the spleen. See Class II. 1. 2. 13. M. M. Venesection. Emetic, cathartic with calomel; then sorbentia, chalybeates, Peruvian bark. 19. _Genu tumor albus._ White swelling of the knee, is owing to deficient absorption of the lymphatics of the membranes including the joint, or capsular ligaments, and sometimes perhaps of the gland which secretes the synovia; and the ends of the bones are probably affected in consequence. I saw an instance, where a caustic had been applied by an empiric on a large white swelling of the knee, and was told, that a fluid had been discharged from the joint, which became anchylosed, and healed without loss of the limb. M. M. Repeated blisters on the part early in the disease are said to cure it by promoting absorption; saturnine solutions externally are recommended. Bark, animal charcoal, as burnt sponge, opium in small doses. Friction with the hand. 20. _Bronchocele._ Swelled throat. An enlargement of the thyroid glands, said to be frequent in mountainous countries, where river water is drank, which has its source from dissolving snows. This idea is a very ancient one, but perhaps not on that account to be the more depended upon, as authors copy one another. Tumidum guttur quis miratur in alpibus, seems to have been a proverb in the time of Juvenal. The inferior people of Derby are much subject to this disease, but whether more so than other populous towns, I can not determine; certain it is, that they chiefly drink the water of the Derwent, which arises in a mountainous country, and is very frequently blackened as it passes through the morasses near its source; and is generally of a darker colour, and attended with a whiter foam, than the Trent, into which it falls; the greater quantity and whiteness of its froth I suppose may be owing to the viscidity communicated to it by the colouring matter. The lower parts of the town of Derby might be easily supplied with spring water from St. Alkmond's well; or the whole of it from the abundant springs near Bowbridge: the water from which might be conveyed to the town in hollow bricks, or clay-pipes, at no very great expence, and might be received into frequent reservoirs with pumps to them; or laid into the houses. M. M. Twenty grains of burnt sponge with ten of nitre made with mucilage into lozenges, and permitted to dissolve slowly under the tongue twice a day, is asserted to cure in a few months; perhaps other animal charcoal, as candle-snuffs, might do the same. I have directed in the early state of this disease a mixture of common salt and water to be held in the mouth, particularly under the tongue, for a few minutes, four or six times a day for many weeks, which has sometimes succeeded, the salt and water is then spit out again, or in part swallowed. Externally vinegar of squills has been applied, or a mercurial plaster, or fomentations of acetated ammoniac; or ether. Some empirics have applied caustics on the bronchocele, and sometimes, I have been told, with success; which should certainly be used where there is danger of suffocation from the bulk of it. One case I saw, and one I was well informed of, where the bronchocele was cured by burnt sponge, and a hectic fever supervened with colliquative sweats; but I do not know the final event of either of them. De Haen affirms the cure of bronchocele to be effected by flowers of zinc, calcined egg-shells, and scarlet cloth burnt together in a close crucible, which was tried with success, as he assured me, by a late lamented physician, my friend, Dr. Small of Birmingham; who to the cultivation of modern sciences added the integrity of ancient manners; who in clearness of head, and benevolence of heart, had few equals, perhaps no superiors. 21. _Scrophula._ King's evil is known by tumours of the lymphatic glands, particularly of the neck. The upper lip, and division of the nostrils is swelled, with a florid countenance, a smooth skin, and a tumid abdomen. Cullen. The absorbed fluids in their course to the veins in the scrophula are arrested in the lymphatic or conglobate glands; which swell, and after a great length of time, inflame and suppurate. Materials of a peculiar kind, as the variolous and venereal matter, when absorbed in a wound, produce this torpor, and consequent inflammation of those lymphatic glands, where they first arrive, as in the axilla and groin. There is reason to suspect, that the tonsils frequently become inflamed, and suppurate from the matter absorbed from carious teeth; and I saw a young lady, who had both the axillary glands swelled, and which suppurated; which was believed to have been caused by her wearing a pair of new green gloves for one day, when she had perspired much, and was much exhausted and fatigued by walking; the gloves were probably dyed in a solution of verditer. These indolent tumours of the lymphatic glands, which constitute the scrophula, originate from the inirritability of those glands; which therefore sooner fall into torpor after having been stimulated too violently by some poisonous material; as the muscles of enfeebled people sooner become fatigued, and cease to act, when exerted, than those of stronger ones. On the same account these scrophulous glands are much longer in acquiring increase of motion, after having been stimulated into inactivity, and either remain years in a state of indolence, or suppurate with difficulty, and sometimes only partially. The difference between scrophulous tumours, and those before described, consists in this; that in those either glands of different kinds were diseased, or the mouths only of the lymphatic glands were become torpid; whereas in scrophula the conglobate glands themselves become tumid, and generally suppurate after a great length of time, when they acquire new sensibility. See Sect. XXXIX. 4. 5. These indolent tumours may be brought to suppurate sometimes by passing electric shocks through them every day for two or three weeks, as I have witnessed. It is probable, that the alternate application of snow or iced water to them, till they become painfully cold, and then of warm flannel or warm water, frequently repeated, might restore their irritability by accumulation of sensorial power; and thence either facilitate their dispersion, or occasion them to suppurate. See Class II. 1. 4. 13. This disease is very frequent amongst the children of the poor in large towns, who are in general ill fed, ill lodged, and ill clothed; and who are further weakened by eating much salt with their scanty meal of insipid vegetable food, which is seldom of better quality than water gruel, with a little coarse bread in it. See diarrhoea of infants, Class I. 1. 2. 5. Scrophulous ulcers are difficult to heal, which is owing to the deficiency of absorption on their pale and flabby surfaces, and to the general inirritability of the system. See Class I. 1. 3. 13. M. M. Plentiful diet of flesh-meat and vegetables with small-beer. Opium, from a quarter of a grain to half a grain twice a day. Sorbentia. Tincture of digitalis, thirty drops twice a day. Externally sea-bathing, or bathing in salt and water, one pound to three gallons, made warm. The application of Peruvian bark in fine powder, seven parts, and white lead, (cerussa) in fine powder one part, mixed together and applied on the ulcers in dry powder, by means of lint and a bandage, to be renewed every day. Or very fine powder of calamy alone, lapis calaminaris. If powder of manganese? 22. _Schirrus._ After the absorbent veins of a gland cease to perform their office, if the secerning arteries of it continue to act some time longer, the fluids are pushed forwards, and stagnate in the receptacles or capillary vessels of the gland; and the thinner part of them only being resumed by the absorbent system of the gland, a hard tumour gradually succeeds; which continues like a lifeless mass, till from some accidental violence it gains sensibility, and produces cancer, or suppurates. Of this kind are the schirrous glands of the breasts, of the lungs, of the mesentery, and the scrophulous tumours about the neck and the bronchocele. Another seat of schirrus is in the membranous parts of the system, as of the rectum intestinum, the urethra, the gula or throat; and of this kind is the verucca or wart, and the clavus pedum, or corns on the toes. A wen sometimes arises on the back of the neck, and sometimes between the shoulders; and by distending the tendinous fascia produces great and perpetual pain. M. M. Mercurial ointment. Cover the part with oiled silk. Extirpation. Electric shocks through the tumour. An issue into the substance of the wen. Opium. Ether externally. 23. _Schirrus recti intestini._ Schirrus of the rectum. A schirrus frequently affects a canal, and by contracting its diameter becomes a painful and deplorable disease. The canals thus obstructed are the rectum, the urethra, the throat, the gall-ducts, and probably the excretory ducts of the lymphatics, and of other glands. The schirrus of the rectum is known by the patient having pain in the part, and being only able to part with liquid feces, and by the introduction of the finger; the swelled part of the intestine is sometimes protruded downwards, and hangs like a valve, smooth and hard to the touch, with an aperture in the centre of it. See a paper on this subject by J. Sherwin. Memoirs of a London Medical Society, Vol. II. p. 9. M. M. To take but little solid food. Aperient medicines. Introduce a candle smeared with mercurial ointment. Sponge-tent. Clysters with forty drops of laudanum. Introduce a leathern canula, or gut, and then either a wooden maundril, or blow it up with air, so as to distend the contracted part as much as the patient can bear. Or spread mercurial plaster on thick soft leather, and roll it up with the plaster outwards to any thickness and length, which can be easily introduced and worn; or two or three such pieces may be introduced after each other. The same may be used to compress bleeding internal piles. See Class I. 2. 1. 6. 24. _Schirrus urethræ._ Schirrus of the urethra. The passage becomes contracted by the thickened membrane, and the urine is forced through with great difficulty, and is thence liable to distend the canal behind the stricture; till at length an aperture is made, and the urine forces its way into the cellular membrane, making large sinuses. This situation sometimes continues many months, or even years, and so much matter is evacuated after making water, or at the same time, by the action of the muscles in the vicinity of the sinuses, that it has been mistaken for an increased secretion from the bladder, and has been erroneously termed a catarrh of the bladder. See a paper by Dr. R. W. Darwin in the Medical Memoirs. M. M. Distend the part gradually by catgut bougies, which by their compression will at the same time diminish the thickness of the membrane, or by bougies of elastic gum, or of horn boiled soft. The patient should gain the habit of making water slowly, which is a matter of the utmost consequence, as it prevents the distention, and consequent rupture, of that part of the urethra, which is between the stricture and the neck of the bladder. When there occurs an external ulcer in the perinæum, and the urine is in part discharged that way, the disease can not be mistaken. Otherwise from the quantity of matter, it is generally supposed to come from the bladder, or prostate gland; and the urine, which escapes from the ruptured urethra, mines its way amongst the muscles and membranes, and the patient dies tabid, owing to the want of an external orifice to discharge the matter. See Class II. 1. 4. 11. 25. _Schirrus oesophagi._ A schirrus of the throat contracts the passage so as to render the swallowing of solids impracticable, and of liquids difficult. It affects patients of all ages, but is probably most frequently produced by swallowing hard angular substances, when people have lost their teeth; by which this membrane is over distended, or torn, or otherwise injured. M. M. Put milk into a bladder tied to a canula or catheter; introduce it past the stricture, and press it into the stomach. Distend the stricture gradually by a sponge-tent fastened to the end of whale-bone, or by a plug of wax, or a spermaceti candle, about two inches long; which might be introduced, and left there with a string only fixed to it to hang out of the mouth, to keep it in its place, and to retract it by occasionally; for which purpose the string must be put through a catheter or hollow probang, when it is to be retracted. Or lastly introduce a gut fixed to a pipe; and then distend it by blowing wind into it. The swallowing a bullet with a string put through it, to retract it on the exhibition of an emetic, has also been proposed. Externally mercurial ointment has been much recommended. Poultice. Oiled silk. Clysters of broth. Warm bath of broth. Transfusion of blood into a vein three or four ounces a day? See Class III. 1. 1. 15. I directed a young woman about twenty-two years of age, to be fed with new milk put into a bladder, which was tied to a catheter, and introduced beyond the stricture in her throat; after a few days her spirits sunk, and she refused to use it further, and died. Above thirty years ago I proposed to an old gentleman, whose throat was entirely impervious, to supply him with a few ounces of blood daily from an ass, or from the human animal, who is still more patient and tractable, in the following manner. To fix a silver pipe about an inch long to each extremity of a chicken's gut, the part between the two silver ends to be measured by filling it with warm water; to put one end into the vein of a person hired for that purpose, so as to receive the blood returning from the extremity; and when the gut was quite full, and the blood running through the other silver end, to introduce that end into the vein of the patient upwards towards the heart, so as to admit no air along with the blood. And lastly, to support the gut and silver ends on a water plate, filled with water of ninety-eight degrees of heat, and to measure how many ounces of blood was introduced by passing the finger, so as to compress the gut, from the receiving pipe to the delivering pipe; and thence to determine how many gut-fulls were given from the healthy person to the patient. See Class IV. 2. 4. 11. Mr. ---- considered a day on this proposal, and then another day, and at length answered, that "he now found himself near the house of death; and that if he could return, he was now too old to have much enjoyment of life; and therefore he wished rather to proceed to the end of that journey, which he was now so near, and which he must at all events soon go, than return for so short a time." He lived but a few days afterwards, and seemed quite careless and easy about the matter. 26. _Lacteorum inirritabilitas._ Inirritability of the lacteals is described in Sect. XXVIII. under the name of paralysis of the lacteals; but as the word paralysis has generally been applied to the disobedience of the muscles to the power of volition, the name is here changed to inirritability of the lacteals, as more characteristic of the disease. 27. _Lymphaticorum inirritabilitas._ The inirritability of the cellular and cutaneous lymphatics is described in Sect. XXIX. 5. 1. and in Class I. 2. 3. 16. The inirritability of the cutaneous lymphatics generally accompanies anasarca, and is the cause of the great thirst in that malady. At the same time the cellular lymphatics act with greater energy, owing to the greater derivation of sensorial power to them in consequence of the less expenditure of it by the cutaneous ones; and hence they absorb the fat, and mucus, and also the thinner parts of the urine. Whence the great emaciation of the body, the muddy sediment, and the small quantity of water in this kind of dropsy. * * * * * ORDO II. _Decreased Irritation._ GENUS IV. _With Decreased Actions of other Cavities and Membranes._ Many of the diseases of this genus are attended with pain, and with cold extremities, both which cease on the exhibition of wine or opium; which shews, that they originate from deficient action of the affected organ. These pains are called nervous or spasmodic, are not attended with fever, but are frequently succeeded by convulsions and madness; both which belong to the class of volition. Some of them return at periods, and when these can be ascertained, a much less quantity of opium will prevent them, than is necessary to cure them, when they are begun; as the vessels are then torpid and inirritable from the want of sensorial power, till by their inaction it becomes again accumulated. Our organs of sense properly so called are not liable to pain from the absence of their appropriated stimuli, as from darkness or silence; but the other senses, which may be more properly called appetites, as those by which we perceive heat, hunger, thirst, lust, want of fresh air, are affected with pain from the defect or absence of their accustomed stimuli, as well as with pleasure by the possession of them; it is probable that some of our glands, whose sense or appetite requires or receives something from the circulating blood, as the pancreas, liver, testes, prostate gland, may be affected with aching or pain, when they cannot acquire their appropriated fluid. Wherever this defect of stimulus occurs, a torpor or inaction of the organ ensues, as in the capillaries of the skin, when exposed to cold; and in the glands, which secrete the gastric juice, when we are hungry. This torpor however, and concomitant pain, which is at first owing to defect of stimulus, is afterwards induced by other associations or catenations, and constitutes the beginning of ague fits. It must be further observed, that in the diseases of pain without fever, the pain is frequently not felt in the part where the cause of the disease resides; but is induced by sympathy with a distant part, whose irritability or sensibility is greater or less than its own. Thus a stone at the neck of the bladder, if its stimulus is not very great, only induces the pain of strangury at the glans penis. If its stimulus be greater, it then induces pain at the neck of the bladder. The concretions of bile, which are protruded into the neck of the gall-bladder, when the disease is not very great, produce pain at the other extremity of the bile-duct, which enters the duodenum immediately under the pit of the stomach; but, when the disease is great from the largeness of the bile-stone, the pain is felt in the region of the liver at the neck of the gall-bladder. It appears from hence, that the pains enumerated in this genus are consequences of the inactivity of the organ; and, as they do not occasion other diseases, should be classed according to their proximate cause, which is defective irritation; there are nevertheless other pains from defect of stimulus, which produce convulsions, and belong to Class III. 1. 1.; and others, which produce pains of some distant part by association, and belong to Class IV. 2. 2. SPECIES. 1. _Sitis._ Thirst. The senses of thirst and of hunger seem to have this connection, that the former is situated at the upper end, and the latter at the lower end of the same canal. One about the pharinx, where the oesophagus opens into the mouth, and the other about the cardia ventriculi, where it opens into the stomach. The extremities of other canals have been shewn to possess correspondent sensibilities, or irritabilities, as the two ends of the urethra, and of the common gall-duct. See IV. 2. 2. 2. and 4. The membrane of the upper end of the gullet becomes torpid, and consequently painful, when there is a deficiency of aqueous fluid in the general system; it then wants its proper stimulus. In the same manner a want of the stimulus of more solid materials at the other end of the canal, which terminates in the stomach, produces hunger; as mentioned in Sect. XIV. 8. The proximate causes of both of them therefore consist in deficient irritation, when they are considered as pains; because these pains are in consequence of the inactivity of the organ, according to the fifth law of animal causation. Sect. IV. 5. But when they are considered as desires, namely of liquid or solid aliment, their proximate cause consists in the pain of them, according to the sixth law of animal causation. So the proximate cause of the pain of coldness is the inactivity of the organ, and perhaps the consequent accumulation of sensorial power in it; but the pain itself, or the consequent volition, is the proximate cause of the shuddering and gnashing the teeth in cold fits of intermittent fevers. See Class I. 2. 2. 1. Thirst may be divided into two varieties alluding to the remote cause of each, and may be termed sitis calida, or warm thirst, and sitis frigida, or cold thirst. The remote cause of the former arises from the dissipation of the aqueous parts of our fluids by the increased secretion of perspirable matter, or other evacuations. And hence it occurs in hot fits of fever, and after taking much wine, opium, spice, salt, or other drugs of the Art. incitantia or secernentia. The thirst, which occurs about three hours after eating a couple of red herrings, to a person unaccustomed to salted meat, is of this kind; the increased action of the cutaneous vessels dissipates so much of our fluids by insensible perspiration, as to require above two quarts of water to restore the fluidity of the blood, and to wash the salt out of the system. See Art. III. 2. 1. M. M. Cold water. Vegetable acids. Warm bath. The remote cause of sitis frigida, or cold thirst, is owing to the inaction of the cutaneous, pulmonary, urinary, and cellular absorbents; whence the blood is deprived of the great supply of moisture, which it ought to receive from the atmosphere, and from the cells of the cellular membrane, and from other cysts; this cause of thirst exists in dropsies, and in the cold fits of intermittents. The desire of fluids, like that of solids, is liable to acquire periods, and may therefore readily become diseased by indulgence in liquids grateful to the palate. Of diseased thirst, the most common is either owing to defect of the action of the numerous absorbent vessels on the neck of the bladder, in which the patient makes much paleish water; or to the defective absorption of the skin and lungs, in which the patient makes but little water, and that high-coloured, and with sediment. In both the tongue and lips are liable to become very dry. The former in its greatest degree attends diabætes, and the latter anasarca. M. M. Warm water, warm wine, warm bath. Opium. Cold bath. Iced water. Lemonade. Cyder. 2. _Esuries._ Hunger has been fancifully ascribed to the sides of the stomach rubbing against each other, and to the increased acidity of the gastric juice corroding the coats of it. If either of these were the cause of hunger, inflammation must occur, when they had continued some time; but, on the contrary, coldness and not heat are attendant on hunger; which evinces, that like thirst it is owing to the inactivity of the membrane, which is the seat of it; while the abundant nerves about the cardia ventriculi, and the pain of hunger being felt in that part, gives great reason to conclude, that it is there situated. The sense of hunger as well as of thirst is liable to acquire habits in respect to the times of its returning painfulness, as well as in respect to the quantity required to satiate its appetency, and hence may become diseased by indulgence, as well as by want of its appropriate stimulus. Those who have been accustomed to distend their stomach by large quantities of animal and vegetable food, and much potation, find a want of distention, when the stomach is empty, which occasions faintness, and is mistaken for hunger, but which does not appear to be the same sensation. I was well informed, that a woman near Lichfield, who eat much animal and vegetable food for a wager, affirmed, that since distending her stomach so much, she had never felt herself satisfied with food; and had in general taken twice as much at a meal, as she had been accustomed to, before she eat so much for a wager. 3. _Nausea sicca._ Dry nausea. Consists in a quiescence or torpor of the mucous or salivary glands, and precedes their inverted motions, described in nausea humida, Class I. 3. 2. 3. In the same manner as sickness of the stomach is a quiescence of that organ preceding the action of vomiting, as explained in Sect. XXXV. 1. 3. This is sometimes induced by disagreeable drugs held in the mouth, at other times of disgustful ideas, and at other times by the association of these actions with those of the stomach; and thus according to its different proximate causes may belong to this, or to the second, or to the fourth class of diseases. M. M. Lemonade. Tasteful food. A blister. Warm bath. 4. _Ægritudo ventriculi._ Sickness of stomach is produced by the quiescence or inactivity of that organ, as is explained in Sect. XXXV. 1. 3. It consists in the state between the usual peristaltic motions of that organ, in the digestion of our aliment, and the retrograde motions of it in vomiting; for it is evident, that the direct motions of it from the cardia to the pylorus must stop, before those in a contrary direction can commence. This sickness, like the nausea above described, is sometimes produced by disgustful ideas, as when nasty objects are seen, and nasty stories related, as well as by the exhaustion of the sensorial power by the stimulus of some emetic drugs, and by the defect of the production of it, as in enfeebled drunkards. Sickness may likewise consist in the retrograde motions of the lymphatics of the stomach, which regurgitate into it the chyle or lymph, which they have lately absorbed, as in Class I. 3. 2. 3. It is probable, that these two kinds of sickness may be different sensations, though they have acquired but one name; as one of them attends hunger, and the other repletion; though either of them may possibly be induced by association with nauseous ideas. M. M. A blister on the back. An emetic. Opium. Crude mercury. Covering the head in bed. See Sect. XXV. 16. Class IV. 1. 1. 2. and 3. 5. _Cardialgia._ Heartburn originates from the inactivity of the stomach, whence the aliment, instead of being subdued by digestion, and converted into chyle, runs into fermentation, producing acetous acid. Sometimes the gastric juice itself becomes so acid as to give pain to the upper orifice of the stomach; these acid contents of the stomach, on falling on a marble hearth, have been seen to produce an effervescence on it. The pain of heat at the upper end of the gullet, when any air is brought up from the fermenting contents of the stomach, is to be ascribed to the sympathy between these two extremities of the oesophagus rather than to the pungency of the carbonic gas, or fixed air; as the sensation in swallowing that kind of air in water is of a different kind. See Class I. 3. 1. 3. and IV. 2. 2. 5. M. M. This disease arising from indigestion is often very pertinacious, and afflicting; and attended with emaciation of the body from want of sufficient chyle. As the saliva swallowed along with our food prevents its fermentation, as appears by the experiments of Pringle and Macbride, some find considerable relief by chewing parched wheat, or mastic, or a lock of wool, frequently in a day, when the pain occurs, and by swallowing the saliva thus effused; a temporary relief is often obtained from antiacids, as aerated alcaline water, Seltzer's water, calcareous earths, alcaline salts made into pills with soap, soap alone, tin, milk, bitters. More permanent use may be had from such drugs as check fermentation, as acid of vitriol; but still more permanent relief from such things as invigorate the digestion, as a blister on the back; a due quantity of vinous spirit and water taken regularly. Steel. Temperance. A sleep after dinner. A waistcoat made so tight as slightly to compress the bowels and stomach. A flannel shirt in winter, not in summer. A less quantity of potation of all kinds. Ten black pepper-corns swallowed after dinner. Half a grain of opium twice a day, or a grain. The food should consist of such things as do not easily ferment, as flesh, shell-fish, sea-biscuit, toasted cheese. I have seen toasted cheese brought up from the stomach 24 hours after it had been swallowed, without apparently having undergone any chemical change. See Class II. 1. 3. 17. and IV. 1. 2. 13. 6. _Arthritis Ventriculi._ Sickness of the stomach in gouty cases is frequently a consequence of the torpor or inflammation of the liver, and then it continues many days or weeks. But when the patient is seized with great pain at the stomach with the sensation of coldness, which they have called an ice-bolt, this is a primary affection of the stomach, and destroys the patient in a few hours, owing to the torpor or inaction of that viscus so important to life. This primary gout of the stomach, as it is a torpor of that viscus, is attended with sensation of coldness, and with real defect of heat, in that part, and may thence be distinguished from the pain occasioned by the passage of a gall-stone into the duodenum, as well as by the weak pulse, and cold extremities; to which must be added, that it affects those only, who have been long afflicted with the gout, and much debilitated by its numerous attacks. M. M. Opium. Vinous spirit. Volatile alcali. Spice. Warmth applied externally to the stomach by hot cloths or fomentation. 7. _Colica flatulenta._ The flatulent colic arises from the too great distention of the bowel by air, and consequent pain. The cause of this disease is the inactivity or want of sufficiently powerful contraction of the coats of the bowel, to carry forwards the gas given up by the fermenting aliment. It is without fever, and generally attended with cold extremities. It is distinguished, first, from the pain occasioned by the passage of a gall-stone, as that is felt at the pit of the stomach, and this nearer the navel. Secondly, it is distinguished from the colica saturnina, or colic from lead, as that arising from the torpor of the liver, or of some other viscus, is attended with greater coldness, and with an aching pain; whereas the flatulent cholic being owing to distention of the muscles of the bowel, the pain is more acute, and the coldness less. Thirdly, it is distinguished from inflammation of the bowels, or ileus, as perpetual vomiting and fever attend this. Fourthly, it is distinguished from cholera, because that is accompanied with both vomiting and diarrhoea. And lastly, from the colica epileptica, or hysteric colic, as that is liable to alternate with convulsion, and sometimes with insanity; and returns by periods. M. M. Spirit of wine and warm water, one spoonful of each. Opium one grain. Spice. Volatile alcali. Warm fomentation externally. Rhubarb. 8. _Colica saturnina._ Colic from lead. The pain is felt about the navel, is rather of an aching than acute kind at first, which increases after meals, and gradually becomes more permanent and more acute. It terminates in paralysis, frequently of the muscles of the arm, so that the hand hangs down, when the arm is extended horizontally. It is not attended with fever, or increase of heat. The seat of the disease is not well ascertained, it probably affects some part of the liver, as a pale bluish countenance and deficiency of bile sometimes attends or succeeds it, with consequent anasarca; but it seems to be caused immediately by a torpor of the intestine, whether this be a primary or secondary affection, as appears from the constipation of the bowels, which attends it; and is always produced in consequence of the great stimulus of lead previously used either internally for a length of time, or externally on a large surface. A delicate young girl, daughter of a dairy farmer, who kept his milk in leaden cisterns, used to wipe off the cream from the edges of the lead with her finger; and frequently, as she was fond of cream, licked it from her finger. She was seized with the saturnine colic, and semi-paralytic wrists, and sunk from general debility. A feeble woman about 40 years of age sprained her ancle, and bruised her leg and thigh; and applied by ill advice a solution of lead over the whole limb, as a fomentation and poultice for about a fortnight. She was then seized with the colica saturnina, lost the use of her wrists, and gradually sunk under a general debility. M. M. First opium one or two grains, then a cathartic of senna, jalap, and oil, as soon as the pain is relieved. Oleum ricini. Alum. Oil of almonds. A blister on the navel. Warm bath. The stimulus of the opium, by restoring to the bowel its natural irritability in this case of painful torpor, assists the action of the cathartic. 9. _Tympanitis._ Tympany consists in an elastic tumor of the abdomen, which sounds on being struck. It is generally attended with costiveness and emaciation. In one kind the air is said to exist in the bowels, in which case the tumor is less equal, and becomes less tense and painful on the evacuation of air. In the other kind the air exists in the cavity of the abdomen, and sometimes is in a few days exchanged for water, and the tympany becomes an ascites. Air may be distinguished in the stomach of many people by the sound on striking it with the fingers, and comparing the sound with that of a similar percussion on other parts of the bowels; but towards the end of fevers, and especially in the puerperal fever, a distention of the abdomen by air is generally a fatal symptom, though the ease, and often cheerfulness, of the patient vainly flatters the attendants. M. M. In the former case a clyster-pipe unarmed may be introduced, and left some time in the rectum, to take off the resistance of the sphincter, and thus discharge the air, as it is produced from the fermenting or putrefying aliment. For this purpose, in a disease somewhat similar in horses, a perforation is made into the rectum on one side of the sphincter; through which fistula the air, which is produced in such great excess from the quantity of vegetable food which they take, when their digestions are impaired, is perpetually evacuated. In both cases also, balsams, essential oil, spice, bandage on the abdomen, and, to prevent the fermentation of the aliment, acid of vitriol, saliva. See Class I. 2. 4. 5. 10. _Hypochondriasis._ The hypochondriac disease consists in indigestion and consequent flatulency, with anxiety or want of pleasureable sensation. When the action of the stomach and bowels is impaired, much gas becomes generated by the fermenting or putrescent aliment, and to this indigestion is catenated languor, coldness of the skin, and fear. For when the extremities are cold for too long a time in some weak constitutions, indigestion is produced by direct sympathy of the skin and the stomach, with consequent heart-burn, and flatulency. The same occurs if the skin be made cold by fear, as in riding over dangerous roads in winter, and hence conversely fear is produced by indigestion or torpor of the stomach by association. This disease is confounded with the fear of death, which is an insanity, and therefore of a totally different nature. It is also confounded with the hysteric disease, which consists in the retrograde motions of the alimentary canal, and of some parts of the absorbent system. The hypochondriasis, like chlorosis, is sometimes attended with very quick pulse; which the patient seems to bear so easily in these two maladies, that if an accidental cough attends them, they may be mistaken for pulmonary consumption; which is not owing primarily to the debility of the heart, but to its direct sympathy with the actions of the stomach. M. M. Blister. A plaster on the abdomen of Burgundy pitch. Opium a grain twice a day. Rhubarb six grains every night. Bark. Steel. Spice. Bath-water. Siesta, or sleep after dinner. Uniform hours of meals. No liquor stronger than small beer, or wine and water. Gentle exercise on horseback in the open air uniformly persisted in. See Cardialgia, I. 2. 4. 5. 11. _Cephalæa._ Head-ach frequently attends the cold paroxysm of intermittents; afflicts inebriates the day after intoxication; and many people who remain too long in the cold bath. In all which cases there is a general inaction of the whole system, and as these membranes about the head have been more exposed to the variations of heat and cold of the atmosphere, they are more liable to become affected so far as to produce sensation, than other membranes; which are usually covered either with clothes, or with muscles, as mentioned in Sect. XXXIII. 2. 10. The promptitude of the membranes about the scalp to sympathize with those of other parts of the system is so great, that this cephalæa without fever, or quickness of pulse, is more frequently a secondary than a primary disease, and then belongs to Class IV. 2. 2. 7. The hemicrania, or partial head-ach, I believe to be almost always a disease from association; though it is not impossible, but a person may take cold on one side of the head only. As some people by sitting always on the same side of the fire in winter are liable to render one side more tender than the other, and in consequence more subject to pains, which have been erroneously termed rheumatic. See Class IV. 2. 2. 7. & 8. M. M. The method of cure consists in rendering the habit more robust, by gentle constant exercise in the open air, flesh diet, small beer at meals with one glass of wine, regular hours of rest and rising, and of meals. The cloathing about the head should be warmer during sleep than in the day; because at that time people are more liable to take cold; that is, the membranous parts of it are more liable to become torpid. As explained in Sect. XVIII. 15. In respect to medicine, two drams of valerian root in powder three or four times a day are recommended by Fordyce. The bark. Steel in moderate quantities. An emetic. A blister. Opium, half a grain twice a day. Decayed teeth should be extracted, particularly such as either ache, or are useless. Cold bath between 60 and 70 degrees of heat. Warm bath of 94 or 98 degrees every day for half an hour during a month. See Class IV. 2. 2. 7. and 8. A solution of arsenic, about the sixteenth part of a grain, is reported to have great effect in this disease. It should be taken thrice a day, if it produces no griping or sickness, for two or three weeks. A medicine of this kind is sold under the name of tasteless ague-drops; but a more certain method of ascertaining the quantity is delivered in the subsequent materia medica, Art. IV. 2. 6. 12. _Odontalgia._ Tooth-ach. The pain has been erroneously supposed, where there is no inflammation, to be owing to some acrid matter from a carious tooth stimulating the membrane of the alveolar process into violent action and consequent pain; but the effect seems to have been mistaken for the cause, and the decay of the tooth to have been occasioned by the torpor and consequent pain of the diseased membrane. First, because the pain precedes the decay of the tooth in regard to time, and is liable to recur, frequently for years, without certainly being succeeded at last by a carious tooth, as I have repeatedly observed. Secondly, because any stimulant drug, as pyrethrum, or oil of cloves, applied to the tooth, or ether applied externally to the cheek, so far from increasing the pain, as they would do if the pained membrane, already acted too strongly, that they frequently give immediate relief like a charm. And thirdly, because the torpor, or deficient action of the membrane, which includes the diseased tooth, occasions the motions of the membranes most connected with it, as those of the cheek and temples, to act with less than their natural energy; and hence a coldness of the cheek is perceived easily by the hand of the patient, comparing it with the other cheek; and the pain of hemicrania is often produced in the temple of the affected side. This coldness of the cheek in common tooth-ach evinces, that the pain is not then caused by inflammation; because in all inflammations so much heat is produced in the secretions of new vessels and fluids, as to give heat to the parts in vicinity. And hence, as soon as the gum swells and inflames along with the cheek, heat is produced, and the pain ceases, owing to the increased exertions of the torpid membrane, excited by the activity of the sensorial power of sensation; which previously existed in its passive state in the painful torpid membrane. See Odontitis, Class II. 1. 4. 7. and IV. 2. 2. 8. M. M. If the painful tooth be found, venesection. Then a cathartic. Afterwards two grains of opium. Camphor and opium, one grain of each held in the mouth; or a drop or two of oil of cloves put on the painful tooth. Ether. If the tooth has a small hole in it, it should be widened within by an instrument, and then stopped with leaf-gold, or leaf-lead; but should be extracted, if much decayed. It is probable that half a small drop of a strong solution of arsenic, put carefully into the hollow of a decayed aching tooth, would destroy the nerve without giving any additional pain; but this experiment requires great caution, lest any of the solution should touch the tongue or gums. Much cold or much heat are equally injurious to the teeth, which are endued with a fine sensation of this universal fluid. The best method of preserving them is by the daily use of a brush, which is not very hard, with warm water and fine charcoal dust. A lump of charcoal should be put a second time into the fire till it is red hot, as soon as it becomes cool the external ashes should be blown off, and it should be immediately reduced to fine powder in a mortar, and kept close stopped in a phial. It takes away the bad smell from decayed teeth, by washing the mouth with this powder diffused in water immediately. The putrid smell of decaying stumps of teeth may be destroyed for a time by washing the mouth with a weak solution of alum in water. If the calcareous crust upon the teeth adheres very firmly, a fine powder of pumice-stone may be used occasionally, or a tooth instrument. Acid of sea-salt, much diluted, may be used; but this very rarely, and with the greatest caution, as in cleaning sea-shells. When the gums are spongy, they should be frequently pricked with a lancet. Should black spots in teeth be cut out? Does the enamel grow again when it has been perforated or abraded? 13. _Otalgia._ Ear-ach sometimes continues many days without apparent inflammation, and is then frequently removed by filling the ear with laudanum, or with ether; or even with warm oil, or warm water. See Class II. 1. 4. 8. This pain of the ear, like hemicrania, is frequently the consequence of association with a diseased tooth; in that case the ether should be applied to the cheek over the suspected tooth, or a grain of opium and as much camphor mixed together and applied to the suspected tooth. In this case the otalgia belongs to the fourth class of diseases. 14. _Pleurodyne chronica._ Chronical pain of the side. Pains of the membranous parts, which are not attended with fever, have acquired the general name of rheumatic; which should, nevertheless, be restricted to those pains which exist only when the parts are in motion, and which have been left after inflammation of them; as described in Class I. 1. 3. 12. The pain of the side here mentioned affects many ladies, and may possibly have been owing to the pressure of tight stays, which has weakened the action of the vessels composing some membranous part, as, like the cold head-ach, it is attended with present debility; in one patient, a boy about ten years old, it was attended with daily convulsions, and was supposed to have originated from worms. The disease is very frequent, and generally withstands the use of blisters on the part; but in some cases I have known it removed by electric shocks repeated every day for a fortnight through the affected side. Pains of the side may be sometimes occasioned by the adhesion of the lungs to the pleura, after an inflammation of them; or to the adhesion of some abdominal viscera to their cavity, or to each other; which also are more liable to affect ladies from the unnatural and ungraceful pressure of tight stays, or by sitting or lying too long in one posture. But in these cases the pain should be more of the smarting, than of the dull kind. M. M. Ether. A blister. A plaster of Burgundy pitch. An issue or seton on the part. Electric shocks. Friction on the part with oil and camphor. Loose dress. Frequent change of posture both in the day and night. Internally opium, valerian, bark. 15. _Sciatica frigida._ Cold sciatica. The pain along the course of the sciatic nerve, from the hip quite down to the top of the foot, when it is not attended with fever, is improperly termed either rheumatism or gout; as it occurs without inflammation, is attended with pain when the limb is at rest; and as the pain attends the course of the nerve, and not the course of the muscles, or of the fascia, which contains them. The theory of Cotunnius, who believed it to be a dropsy of the sheath of the nerve, which was compressed by the accumulated fluid, has not been confirmed by dissection. The disease seems to consist of a torpor of this sheath of the nerve, and the pain seems to be in consequence of this torpor. See Class II. 1. 2. 18. M. M. Venesection. A cathartic. And then one grain of calomel and one of opium every night for ten successive nights. And a blister, at the same time, a little above the knee-joint on the outside of the thigh, where the sciatic nerve is not so deep seated. Warm bath. Cold bath. Cover the limb with oiled silk, or with a plaster-bandage of emplastrum de minio. 16. _Lumbago frigida._ Cold lumbago. When no fever or inflammation attends this pain of the loins, and the pain exists without motion, it belongs to this genus of diseases, and resembles the pain of the loins in the cold fit of ague. As these membranes are extensive, and more easily fall into quiescence, either by sympathy, or when they are primarily affected, this disease becomes very afflicting, and of great pertinacity. See Class II. 1. 2. 17. M. M. Venesection. A cathartic. Issues on the loins. Adhesive plaster on the loins. Blister on the os sacrum. Warm bath. Cold bath. Remove to a warmer climate in the winter. Loose dress about the waist. Friction daily with oil and camphor. 17. _Hysteralgia frigida._ Cold pain of the uterus preceding or accompanying menstruation. It is attended with cold extremities, want of appetite, and other marks of general debility. M. M. A clyster of half a pint of gruel, and 30 drops of laudanum; or a grain of opium and six grains of rhubarb every night. To sit over warm water, or go into a warm bath. 18. _Proctalgia frigida._ Cold pain at the bottom of the rectum previous to the tumor of the piles, which sometimes extends by sympathy to the loins; it seems to be similar to the pain at the beginning of menstruation, and is owing to the torpor or inirritability of the extremity of the alimentary canal, or to the obstruction of the blood in its passage through the liver, when that viscus is affected, and its consequent delay in the veins of the rectum, occasioning tumors of them, and dull sensations of pain. M. M. Calomel. A cathartic. Spice. Clyster, with 30 drops of laudanum. Sitting over warm water. If chalybeates after evacuation? See Class I. 2. 3. 23. and I. 2. 1. 6. 19. _Vesicæ felleæ inirritabilitas._ The inirritability of the gall-bladder probably occasions one kind of _icterus_, or jaundice; which is owing to whatever obstructs the passage of bile into the duodenum. The jaundice of aged people, and which attends some fevers, is believed to be most frequently caused by an irritative palsy of the gall-bladder; on which account the bile is not pressed from the cyst by its contraction, as in a paralysis of the urinary bladder. A thickening of the coats of the common bile-duct by inflammation or increased action of their vessels so as to prevent the passage of the bile into the intestine, in the same manner as the membrane, which lines the nostrils, becomes thickened in catarrh so as to prevent the passage of air through them, is probably another frequent cause of jaundice, especially of children; and generally ceases in about a fortnight, like a common catarrh, without the aid of medicine; which has given rise to the character, which charms have obtained in some countries for curing the jaundice of young people. The spissitude of the bile is another cause of jaundice, as mentioned in Class I. 1. 3. 8. This also in children is a disease of little danger, as the gall-ducts are distensible, and will the easier admit of the exclusion of gall-stones; but becomes a more serious disease in proportion to the age of the patient, and his habits of life in respect to spirituous potation. A fourth cause of jaundice is the compression of the bile-duct by the enlargement of an inflamed or schirrous liver; this attends those who have drank much spirituous liquor, and is generally succeeded by dropsy and death. M. M. Repeated emetics. Mild cathartics. Warm bath. Electricity. Bitters. Then steel, which, when the pain and inflammation is removed by evacuations, acts like a charm in removing the remainder of the inflammation, and by promoting the absorption of the new vessels or fluids; like the application of any acrid eye-water at the end of ophthalmia; and thus the thickened coats of the bile-duct become reduced, or the enlargement of the liver lessened, and a free passage is again opened for the bile into the intestine. Ether with yolk of egg is recommended, as having a tendency to dissolve inspissated bile. And a decoction of madder is recommended for the same purpose; because the bile of animals, whose food was mixed with madder, was found always in a dilute state. Aerated alcaline water, or Seltzer's water. Raw cabbage, and other acrid vegetables, as water-cresses, mustard. Horses are said to be subject to inspissated bile, with yellow eyes, in the winter season, and to get well as soon as they feed on the spring grass. The largest bile-stone I have seen was from a lady, who had parted with it some years before, and who had abstained above ten years from all kinds of vegetable diet to prevent, as she supposed, a colic of her stomach, which was probably a pain of the biliary duct; on resuming the use of some vegetable diet, she recovered a better state of health, and formed no new bilious concretions. A strong aerated alcaline water is sold by J. Schweppe, No. 8, King's-street, Holborn. See Class I. 1. 3. 10. 20. _Pelvis renalis inirritabilitas._ Inirritability of the pelvis of the kidney. When the nucleus of a stone, whether it be inspissated mucus, or other matter, is formed in the extremity of any of the tubuli uriniferi, and being detached from thence falls into the pelvis of the kidney, it is liable to lodge there from the want of due irritability of the membrane; and in that situation increases by new appositions of indurated animal matter, in the same manner as the stone of the bladder. This is the general cause of hæmorrhage from the kidney; and of obtuse pain in it on exercise; or of acute pain, when the stone advances into the ureter. See Class I. 1. 3. 9. * * * * * ORDO II. _Decreased Irritation._ GENUS V. _Decreased Action of the Organs of Sense._ SPECIES. 1. _Stultitia inirritabilis._ Folly from inirritability. Dulness of perception. When the motions of the fibrous extremities of the nerves of sense are too weak to excite sensation with sufficient quickness and vigour. The irritative ideas are nevertheless performed, though perhaps in a feeble manner, as such people do not run against a post, or walk into a well. There are three other kinds of folly; that from deficient sensation, from deficient volition, and from deficient association, as will be mentioned in their places. In delirium, reverie, and sleep, the power of perception is abolished from other causes. 2. _Visus imminutus._ Diminished vision. In our approach to old age our vision becomes imperfect, not only from the form of the cornea, which becomes less convex, and from its decreased transparency mentioned in Class I. 2. 3. 26.; but also from the decreased irritability of the optic nerve. Thus, in the inirritative or nervous fever, the pupil of the eye becomes dilated; which in this, as well as in the dropsy of the brain, is generally a fatal symptom. A part of the cornea as well as a part of the albuginea in these fevers is frequently seen during sleep; which is owing to the inirritability of the retina to light, or to the general paresis of muscular action, and in consequence to the less contraction of the sphincter of the eye, if it may be so called, at that time. There have been instances of some, who could not distinguish certain colours; and yet whose eyes, in other respects, were not imperfect. Philos. Transact. Which seems to have been owing to the want of irritability, or the inaptitude to action, of some classes of fibres which compose the retina. Other permanent defects depend on the diseased state of the external organ. Class I. 1. 3. 14. I. 2. 3. 25. IV. 2. 1. 11. 3. _Muscæ volitantes._ Dark spots appearing before the eyes, and changing their apparent place with the motions of the eyes, are owing to a temporary defect of irritability of those parts of the retina, which have been lately exposed to more luminous objects than the other parts of it, as explained in Sect. XL. 2. Hence dark spots are seen on the bed-clothes by patients, when the optic nerve is become less irritable, as in fevers with great debility; and the patients are perpetually trying to pick them off with their fingers to discover what they are; for these parts of the retina of weak people are sooner exhausted by the stimulus of bright colours, and are longer in regaining their irritability. Other kinds of ocular spectra, as the coloured ones, are also more liable to remain in the eyes of people debilitated by fevers, and to produce various hallucinations of sight. For after the contraction of a muscle, the fibres of it continue in the last situation, till some antagonist muscles are exerted to retract them; whence, when any one is much exhausted by exercise, or by want of sleep, or in fevers, it is easier to let the fibres of the retina remain in their last situation, after having been stimulated into contraction, than to exert any antagonist fibres to replace them. As the optic nerves at their entrance into the eyes are each of them as thick as a crow-quill, it appears that a great quantity of sensorial power is expended during the day in the perpetual activity of our sense of vision, besides that used in the motions of the eye-balls and eyelids; as much I suppose as is expended in the motions of our arms, which are supplied with nerves of about the same diameters. From hence we may conclude, that the light should be kept from patients in fevers with debility, to prevent the unnecessary exhaustion of the sensorial power. And that on the same account their rooms should be kept silent as well as dark; that they should be at rest in an horizontal posture; and be cooled by a blast of cool air, or by washing them with cold water, whenever their skins are warmer than natural. 4. _Strabismus._ Squinting is generally owing to one eye being less perfect than the other; on which account the patient endeavours to hide the worst eye in the shadow of the nose, that his vision by the other may not be confused. Calves, which have an hydatide with insects inclosed in it in the frontal sinus on one side, turn towards the affected side; because the vision on that side, by the pressure of the hydatide, becomes less perfect; and the disease being recent, the animal turns round, expecting to get a more distinct view of objects. In the hydrocephalus internus, where both eyes are not become insensible, the patient squints with only one eye, and views objects with the other, as in common strabismus. In this case it may be known on which side the disease exists, and that it does not exist on both sides of the brain; in such circumstances, as the patients I believe never recover as they are now treated, might it not be adviseable to perforate the cranium over the ventricule of the affected side? which might at least give room and stimulus to the affected part of the brain? M. M. If the squinting has not been confirmed by long habit, and one eye be not much worse than the other, a piece of gauze stretched on a circle of whale-bone, to cover the best eye in such a manner as to reduce the distinctness of vision of this eye to a similar degree of imperfection with the other, should be worn some hours every day. Or the better eye should be totally darkened by a tin cup covered with black silk for some hours daily, by which means the better eye will be gradually weakened by the want of use, and the worse eye will be gradually strengthened by using it. Covering an inflamed eye in children for weeks together, is very liable to produce squinting, for the same reason. 5. _Amaurosis._ Gutta serena. Is a blindness from the inirritability of the optic nerve. It is generally esteemed a palsy of the nerve, but should rather be deemed the death of it, as paralysis has generally been applied to a deprivation only of voluntary power. This is a disease of dark eyes only, as the cataract is a disease of light eyes only. At the commencement of this disease, very minute electric shocks should be repeatedly passed through the eyes; such as may be produced by putting one edge of a piece of silver the size of a half-crown piece beneath the tongue, and one edge of a piece of zinc of a similar size between the upper lip and the gum, and then repeatedly bringing their exterior edges into contact, by which means very small electric sparks become visible in the eyes. See additional note at the end of the first volume, p. 567. and Sect. XIV. 5. M. M. Minute electric shocks. A grain of opium, and a quarter of a grain of corrosive sublimate of mercury, twice a day for four or six weeks. Blister on the crown of the head. 6. _Auditus imminutus._ Diminished hearing. Deafness is a frequent symptom in those inflammatory or sensitive fevers with debility, which are generally called putrid; it attends the general stupor in those fevers, and is rather esteemed a salutary sign, as during this stupor there is less expenditure of sensorial power. In fevers of debility without inflammation, called nervous fevers, I suspect deafness to be a bad symptom, arising like the dilated pupil from a partial paralysis of the nerve of sense. See Class IV. 2. 1. 15. Nervous fevers are supposed by Dr. Gilchrist to originate from a congestion of serum or water in some part of the brain, as many of the symptoms are so similar to those of hydrocephalus internus, in which a fluid is accumulated in the ventricules of the brain; on this idea the inactivity of the optic or auditory nerves in these fevers may arise from the compression of the effused fluid; while the torpor attending putrid fever may depend on the meninges of the brain being thickened by inflammation, and thus compressing it; now the new vessels, or the blood, which thickens inflamed parts, is more frequently reabsorbed, than the effused fluid from a cavity; and hence the stupor in one case is less dangerous than in the other. In inflammatory or sensitive fevers with debility, deafness may sometimes arise from a greater secretion and absorption of the ear-wax, which is very similar to the bile, and is liable to fill the meatus auditorius, when it is too viscid, as bile obstructs the gall-ducts. M. M. In deafness without fever Dr. Darwin applied a cupping-glass on the ear with good effect, as described in Phil. Trans. Vol. LXIV. p. 348. Oil, ether, laudanum, dropped into the ears. 7. _Olfactus imminutus._ Inactivity of the sense of smell. From our habits of trusting to the art of cookery, and not examining our food by the smell as other animals do, our sense of smell is less perfect than theirs. See Sect. XVI. 5. Class IV. 2. 1. 16. M. M. Mild errhines. 8. _Gustus imminutus._ Want of taste is very common in fevers, owing frequently to the dryness or scurf of the tongue, or external organ of that sense, rather than to any injury of the nerves of taste. See Class. I. 1. 3. 1. IV. 2. 1. 16. M. M. Warm subacid liquids taken frequently. 9. _Tactus imminutus._ Numbness is frequently complained of in fevers, and in epilepsy, and the touch is sometimes impaired by the dryness of the cuticle of the fingers. See Class IV. 2. 1. 16. When the sense of touch is impaired by the compression of the nerve, as in sitting long with one thigh crossed over the other, the limb appears larger, when we touch it with our hands, which is to be ascribed to the indistinctness of the sensation of touch, and may be explained in the same manner as the apparent largeness of objects seen through a mist. In this last case the minute parts of an object, as suppose of a distant boy, are seen less distinctly, and therefore we instantly conceive them to be further from the eye, and in consequence that the whole subtends a larger angle, and thus we believe the boy to be a man. So when any one's fingers are pressed on a benumbed limb, the sensation produced is less than it should be, judging from visible circumstances; we therefore conceive, that something intervened between the object and the sense, for it is felt as if a blanket was put between them; and that not being visibly the case, we judge that the limb is swelled. The sense of touch is also liable to be deceived from the acquired habits of one part of it acting in the vicinity of another part of it. Thus if the middle finger be crossed over either of the fingers next to it, and a nut be felt by the two ends of the fingers so crossed at the same time, the nut appears as if it was two nuts. And lastly, the sense of touch is liable to be deceived by preconceived ideas; which we believe to be excited by external objects, even when we are awake. It has happened to me more than once, and I suppose to most others, to have put my hands into an empty bason standing in an obscure corner of a room to wash them, which I believed to contain cold water, and have instantly perceived a sensation of warmth, contrary to that which I expected to have felt. In some paralytic affections, and in cold fits of ague, the sensation of touch has been much impaired, and yet that of heat has remained, See Sect. XIV. 6. M. M. Friction alone, or with camphorated oil, warm bath. Ether. Volatile alcali and water. Internally spice, salt. Incitantia. Secernentia. 10. _Stupor._ The stupor, which occurs in fevers with debility, is generally esteemed a favourable symptom; which may arise from the less expenditure of sensorial power already existing in the brain and nerves, as mentioned in species 6 of this genus. But if we suppose, that there is a continued production of sensorial power, or an accumulation of it in the torpid parts of the system, which is not improbable, because such a production of it continues during sleep, to which stupor is much allied, there is still further reason for believing it to be a favourable symptom in inirritable fevers; and that much injury is often done by blisters and other powerful stimuli to remove the stupor. See Sect. XII. 7. 8. and XXXIII. 1. 4. Dr. Blane in his Croonian Lecture on muscular motion for 1788, among many other ingenious observations and deductions, relates a curious experiment on salmon, and other fish, and which he repeated upon eels with similar event. "If a fish, immediately upon being taken out of the water, is stunned by a violent blow on the head, or by having the head crushed, the irritability and sweetness of the muscles will be preserved much longer, than if it had been allowed to die with the organs of sense entire. This is so well known to fishermen, that they put it in practice, in order to make them longer susceptible of the operation called _crimping_. A salmon is one of the fish least tenacious of life, insomuch, that it will lose all signs of life in less than half an hour after it is taken out of the water, if suffered to die without any farther injury; but if, immediately after being caught, it receives a violent blow on the head, the muscles will shew visible irritability for more than twelve hours afterwards." Dr. Blane afterwards well remarks, that "in those disorders in which the exercise of the senses is in a great measure destroyed, or suspended, as in the hydrocephalus, and apoplectic palsy, it happens not uncommonly, that the appetite and digestion are better than in health." * * * * * ORDO III. _Retrograde Irritative Motions._ GENUS I. _Of the Alimentary Canal._ The retrograde motions of our system originate either from defect of stimulus, or from defect of irritability. Thus sickness is often induced by hunger, which is a want of stimulus; and from ipecacuanha, in which last case it would seem, that the sickness was induced after the violence of the stimulus was abated, and the consequent torpor had succeeded. Hence spice, opium, or food relieves sickness. The globus hystericus, salivation, diabætes, and other inversions of motion attending hysteric paroxysms, seem to depend on the want of irritability of those parts of the body, because they are attended with cold extremities, and general debility, and are relieved by wine, opium, steel, and flesh diet; that is, by any additional stimulus. When the longitudinal muscles are fatigued by long action, or are habitually weaker than natural, the antagonist muscles replace the limb by stretching it in a contrary direction; and as these muscles have had their actions associated in synchronous tribes, their actions cease together. But as the hollow muscles propel the fluids, which they contain, by motions associated in trains; when one ring is fatigued from its too great debility, and brought into retrograde action; the next ring, and the next, from its association in train falls into retrograde action. Which continue so long as they are excited to act, like the tremors of the hands of infirm people, so long as they endeavour to act. Now as these hollow muscles are perpetually stimulated, these retrograde actions do not cease as the tremors of the longitudinal muscles, which are generally excited only by volition. Whence the retrograde motions of hollow muscles depend on two circumstances, in which they differ from the longitudinal muscles, namely, their motions being associated in trains, and their being subject to perpetual stimulus. For further elucidation of the cause of this curious source of diseases, see Sect. XXIX. 11. 5. The fluids disgorged by the retrograde motions of the various vascular muscles may be distinguished, 1. From those, which are produced by secretion, by their not being attended by increase of heat, which always accompanies increased secretion. 2. They may be distinguished from those fluids, which are the consequence of deficient absorption, by their not possessing the saline acrimony, which those fluids possess; which inflames the skin or other membranes on which they fall; and which have a saline taste to the tongue. 3. They may be distinguished from those fluids, which are the consequence both of increased secretion and absorption, as these are attended with increase of warmth, and are inspissated by the abstraction of their aqueous parts. 4. Where chyle, or milk, are found in the feces or urine, or when other fluids, as matter, are translated from one part of the system to another, they have been the product of retrograde action of lymphatic or other canals. As explained in Sect. XXIX. 8. SPECIES. 1. _Ruminatio._ In the rumination of horned cattle the retrograde motions of the oesophagus are visible to the eye, as they bring up the softened grass from their first stomach. The vegetable aliment in the first stomach of cattle, which have filled themselves too full of young clover, is liable to run into fermentation, and distend the stomach, so as to preclude its exit, and frequently to destroy the animal. To discharge this air the farmers frequently make an opening into the stomach of the animal with success. I was informed, I believe by the late Dr. Whytt of Edinburgh, that of twenty cows in this situation two had died, and that he directed a pint of gin or whisky, mixed with an equal quantity of water, to be given to the other eighteen; all of which eructed immense quantities of air, and recovered. There are histories of ruminating men, and who have taken pleasure in the act of chewing their food a second time. Philos. Transact. 2. _Ructus._ Eructation. An inverted motion of the stomach excluding through its upper valve an elastic vapour generated by the fermentation of the aliment; which proceeds so hastily, that the digestive power does not subdue it. This is sometimes acquired by habit, so that some people can eruct when they please, and as long as they please; and there is gas enough generated to supply them for this purpose; for by Dr. Hale's experiments, an apple, and many other kinds of aliment, give up above six hundred times their own bulk of an elastic gas in fermentation. When people voluntarily eject the fixable air from their stomachs, the fermentation of the aliment proceeds the faster; for stopping the vessels, which contain new wines, retards their fermentation, and opening them again accelerates it; hence where the digestion is impaired, and the stomach somewhat distended with air, it is better to restrain than to encourage eructations, except the quantity makes it necessary. When wine is confined in bottles the fermentation still proceeds slowly even for years, till all the sugar is converted into spirit; but in the process of digestion, the saccharine part is absorbed in the form of chyle by the bibulous mouths of the numerous lacteals, before it has time to run into the vinous fermentation. 3. _Apepsia._ Indigestion. Water-qualm. A few mouthfuls of the aliment are rejected at a time for some hours after meals. When the aliment has had time to ferment, and become acid, it produces cardialgia, or heart-burn. This disease is perhaps generally left after a slight inflammation of the stomach, called a surfeit, occasioned by drinking cold liquors, or eating cold vegetables, when heated with exercise. This inflammation of the stomach is frequently, I believe, at its commencement removed by a critical eruption on the face, which differs in its appearance as well as in its cause from the gutta rosea of drunkards, as the skin round the base of each eruption is less inflamed. See Class II. 1. 4. 6.. This disease differs from Cardialgia, Class I. 2. 4. 5. in its being not uniformly attended with pain of the cardia ventriculi, and from its retrograde motions of a part of the stomach about the upper orifice of it. In the same manner as hysteria differs from hypochondriasis; the one consisting in the weakness and indigestion of the same portions of the alimentary canal, and the other in the inverted motions of some parts of it. This apepsia or water-qualm continues many years, even to old age; Mr. G---- of Lichfield suffered under this disease from his infancy; and, as he grew old, found relief only from repeated doses of opium. M. M. A blister, rhubarb, a grain of opium twice a day. Soap, iron-powder. Tin-powder. 4. _Vomitus._ An inverted order of the motions of the stomach and oesophagus with their absorbent vessels, by which their contents are evacuated. In the act of vomiting less sensorial power is employed than in the usual peristaltic motion of the stomach, as explained in Sect. XXXV. 1. 3. Whence after the operation of an emetic the digestion becomes stronger by an accumulation of sensorial power during its decreased action. This decreased action of the stomach may be either induced by want of stimulus, as in the sickness which attends hunger; or it may be induced by temporary want of irritability, as in cold fits of fever; or from habitual want of irritability, as the vomiting of enfeebled drunkards. Or lastly, by having been previously too violently stimulated by an emetic drug, as by ipecacuanha. M. M. A blister. An emetic. Opium. Warmth of a bed, covering the face for a while with the bed-clothes. Crude mercury. A poultice with opium or theriaca externally. 5. _Cholera._ When not only the stomach, as in the last article, but also the duodenum, and ilium, as low as the valve of the colon, have their motions inverted; and great quantities of bile are thus poured into the stomach; while at the same time some branches of the lacteals become retrograde, and disgorge their contents into the upper part of the alimentary canal; and other branches of them disgorge their contents into the lower parts of it beneath the valve of the colon; a vomiting and purging commence together, which is called cholera, as it is supposed to have its origin from increased secretion of bile; but I suppose more frequently arises from putrid food, or poisonous drugs, as in the case narrated in Sect. XXV. 13. where other circumstances of this disease are explained. See Class II. 1. 2. 11. The cramps of the legs, which are liable to attend cholera, are explained in Class III. 1. 1. 14. 6. _Ileus._ Consists in the inverted motions of the whole intestinal canal, from the mouth to the anus; and of the lacteals and absorbents which arise from it. In this pitiable disease, through the valve of the colon, through the pylorus, the cardia, and the pharinx, are ejected, first, the contents of the stomach and intestines, with the excrement and even clysters themselves; then the fluid from the lacteals, which is now poured into the intestines by their retrograde motions, is thrown up by the mouth; and, lastly, every fluid, which is absorbed by the other lymphatic branches, from the cellular membrane, the skin, the bladder, and all other cavities of the body; and which is then poured into the stomach or intestines by the retrograde motions of the lacteals; all which supply that amazing quantity of fluid, which is in this disease continually ejected by vomiting. See Sect. XXV. 15. for a further explanation of this disease. M. M. Copious venesection. Twenty grains of calomel in small pills, or one grain of aloe every hour till stools are procured. Blisters. Warm bath. Crude mercury. Clyster of ice-water. Smear the skin all over with grease, as mentioned in Sect. XXV. 15. As this malady is occasioned sometimes by an introsusception of a part of the intestine into another part of it, especially in children, could holding them up by their heels for a second or two of time be of service after venesection? Or the exhibition of crude quicksilver two ounces every half hour, till a pound is taken, be particularly serviceable in this circumstance? Or could half a pound, or a pound, of crude mercury be injected as a clyster, the patient being elevated by the knees and thighs so as to have his head and shoulders much lower than his bottom, or even for a short time held up by the heels? Could this also be of advantage in strangulated hernia? Where the disease is owing to strangulated hernia, the part should be sprinkled with cold water, or iced water, or salt and water recently mixed, or moistened with ether. In cases of strangulated hernia, could acupuncture, or puncture with a capillary trocar, be used with safety and advantage to give exit to air contained in the strangulated bowel? Or to stimulate it into action? It is not uncommon for bashful men to conceal their being afflicted with a small hernia, which is the cause of their death; this circumstance should therefore always be enquired into. Is the seat or cause of the ileus always below the valve of the colon, and that of the cholera above it? See Class II. 1. 2. 11. 7. _Globus hystericus._ Hysteric suffocation is the perception of a globe rolling round in the abdomen, and ascending to the stomach and throat, and there inducing strangulation. It consists of an ineffectual inversion of the motions of the oesophagus, and other parts of the alimentary canal; nothing being rejected from the stomach. M. M. Tincture of castor. Tinct. of opium of each 15 drops. See Hysteria, Class I. 3. 1. 10. 8. _Vomendi conamen inane._ An ineffectual effort to vomit. It frequently occurs, when the stomach is empty, and in some cases continues many hours; but as the lymphatics of the stomach are not inverted at the same time, there is no supply of materials to be ejected; it is sometimes a symptom of hysteria, but more frequently attends irregular epilepsies or reveries; which however may be distinguished by their violence of exertion, for the exertions of hysteric motions are feeble, as they are caused by debility; but those of epilepsies, as they are used to relieve pain, are of the most violent kind; insomuch that those who have once seen these ineffectual efforts to vomit in some epilepsies, can never again mistake them for symptoms of hysteria. See a case in Sect. XIX. 2. M. M. Blister. Opium. Crude mercury. 9. _Borborigmus._ A gurgling of the bowels proceeds from a partial invertion of the peristaltic motions of them, by which the gas is brought into a superior part of the bowel, and bubbles through the descending fluid, like air rushing into a bottle as the water is poured out of it. This is sometimes a distressing symptom of the debility of the bowels joined with a partial inversion of their motions. I attended a young lady about sixteen, who was in other respects feeble, whose bowels almost incessantly made a gurgling noise so loud as to be heard at a considerable distance, and to attract the notice of all who were near her. As this noise never ceased a minute together for many hours in a day, it could not be produced by the uniform descent of water, and ascent of air through it, but there must have been alternately a retrograde movement of a part of the bowel, which must again have pushed up the water above the air; or which might raise a part of the bowel, in which the fluid was lodged, alternately above and below another portion of it; which might readily happen in some of the curvatures of the smaller intestines, the air in which might be moved backward and forward like the air-bubble in a glass-level. M. M. Essential oil. Ten corns of black pepper swallowed whole after dinner, that its effect might be slower and more permanent; a small pipe occasionally introduced into the rectum to facilitate the escape of the air. Crude mercury. See Class I. 2. 4. 9. 10. _Hysteria._ The three last articles, together with the lymphatic diabætes, are the most common symptoms of the hysteric disease; to which sometimes is added the lymphatic salivation, and fits of syncope, or convulsion, with palpitation of the heart (which probably consists of retrograde motions of it), and a great fear of dying. Which last circumstance distinguishes these convulsions from the epileptic ones with greater certainty than any other single symptom. The pale copious urine, cold skin, palpitation, and trembling, are the symptoms excited by great fear. Hence in hysteric diseases, when these symptoms occur, the fear, which has been usually associated with them, recurs at the same time, as in hypochondriasis, Class I. 2. 4. 10. See Sect. XVI. 8. 1. The convulsions which sometimes attend the hysteric disease, are exertions to relieve pain, either of some torpid, or of some retrograde organ; and in this respect they resemble epileptic convulsions, except that they are seldom so violent as entirely to produce insensibility to external stimuli; for these weaker pains cease before the total exhaustion of sensorial power is produced, and the patient sinks into imperfect syncope; whereas the true epilepsy generally terminates in temporary apoplexy, with perfect insensibility to external objects. These convulsions are less to be dreaded than the epileptic ones, as they do not originate from so permanent a cause. The great discharge of pale urine in this disease is owing to the inverted motions of the lymphatics, which arise about the neck of the bladder, as described in Sect. XXIX. 4. 5. And the lymphatic salivation arises from the inverted motions of the salivary lymphatics. Hysteria is distinguished from hypochondriasis, as in the latter there are no retrograde motions of the alimentary canal, but simply a debility or inirritability of it, with distention and flatulency. It is distinguished from apepsia and cardialgia by there being nothing ejected from the stomach by the retrograde motions of it, or of the oesophagus. M. M. Opium. Camphor. Assafoetida. Castor, with sinapisms externally; to which must be added a clyster of cold water, or iced water; which, according to Mons. Pomme, relieves these hysteric symptoms instantaneously like a charm; which it may effect by checking the inverted motions of the intestinal canal by the torpor occasioned by cold; or one end of the intestinal canal may become strengthened, and regain its peristaltic motion by reverse sympathy, when the other end is rendered torpid by ice-water. (Pomme des Affections Vaporeuses, p. 25.) These remove the present symptoms; and bark, steel, exercise, coldish bath, prevent their returns. See Art. VI. 2. 1. 11. _Hydrophobia._ Dread of water occasioned by the bite of a mad dog, is a violent inversion of the motions of the oesophagus on the contact or even approach of water or other fluids. The pharinx seems to have acquired the sensibility of the larinx in this disease, and is as impatient to reject any fluid, which gets into it. Is not the cardia ventriculi the seat of this disease? As in cardialgia the pain is often felt in the pharinx, when the acid material stimulates the other end of the canal, which terminates in the stomach. As this fatal disease resembles tetanus, or locked jaw, in its tendency to convulsion from a distant wound, and affects some other parts by association, it is treated of in Class III. 1. 1. 15. and IV. 1. 2. 7. * * * * * ORDO III. _Retrograde Irritative Motions._ GENUS II. _Of the Absorbent System._ SPECIES. 1. _Catarrhus lymphaticus._ Lymphatic catarrh. A periodical defluxion of a thin fluid from the nostrils, for a few hours, occasioned by the retrograde motions of their lymphatics; which may probably be supplied with fluid by the increased absorption of some other lymphatic branches in their vicinity. It is distinguished from that mucous discharge, which happens in frosty weather from decreased absorption, because it is less salt to the taste; and from an increased secretion of mucus, because it is neither so viscid, nor is attended with heat of the part. This complaint is liable to recur at diurnal periods, like an intermittent fever, for weeks and months together, with great sneezing and very copious discharge for an hour or two. I have seen two of these cases, both of which occurred in delicate women, and seemed an appendage to other hysteric symptoms; whence I concluded, that the discharge was occasioned by the inverted motions of the lymphatics of the nostrils, like the pale urine in hysteric cases; and that they might receive this fluid from some other branches of lymphatic vessels opening into the frontal or maxillary cavities in their vicinity. Could such a discharge be produced by strong errhines, and excite an absorption of the congestion of lymph in the dropsy of the brain? 2. _Salivatio lymphatica._ Lymphatic salivation. A copious expuition of a pellucid insipid fluid, occasioned by the retrograde motions of the lymphatics of the mouth. It is sometimes periodical, and often attends the hysteric disease, and nervous fevers; but is not accompanied with a saline taste, or with heat of the mouth, or nausea. 3. _Nausea humida._ Moist nausea consists in a discharge of fluid, owing to the retrograde motions of the lymphatics about the fauces, without increase of heat, or saline taste, together with some retrograde motions of the fauces or pharinx; along with this nausea a sickness generally precedes the act of vomiting; which may consist of a similar discharge of mucus or chyle into the stomach by the retrograde motions of the lymphatics or lacteals, which open into it. See Class I. 2. 4. 3. and I. 2. 4. 4. M. M. Subacid liquids. Wine. Opium. A blister. 4. _Diarrhoea lymphatica._ Lymphatic diarrhoea. A quantity of mucus and lymph are poured into the intestines by the inverted motions of the intestinal lymphatics. The feces are less fetid and more liquid; and it sometimes portends the commencement of a diabætes, or dropsy, or their temporary relief. This lymphatic diarrhoea sometimes becomes chronical, in which the atmospheric moisture, absorbed by the cutaneous and pulmonary lymphatics, is poured into the intestines by the retrograde motions of the lacteals. See Section XXIX. 4. 6. where some cases of this kind are related. 5. _Diarrhoea chylifera, coeliaca._ Chyliferous diarrhoea. The chyle drank up by the lacteals of the upper intestines is poured into the lower ones by the retrograde motions of their lacteals, and appears in the dejections. This circumstance occurs at the beginning of diarrhoea crapulosa, where the patient has taken and digested more aliment than the system can conveniently receive, and thus eliminates a part of it; as appears when there is curdled chyle in some of the dejections. See Sect. XXIX. 4. 7. It differs from the lymphatic diarrhoea, as the chyliferous diabætes differs from the aqueous and mucaginous diabætes. 6. _Diabætes._ By the retrograde motions of the urinary lymphatics, an immense quantity of fluid is poured into the bladder. It is either termed chyliferous, or aqueous, or mucaginous, from the nature of the fluid brought into the bladder; and is either a temporary disease, as in hysteric women, in the beginning of intoxication, in worm cases, or in those exposed to cold damp air, or to great fear, or anxiety, or in the commencement of some dropsies; or it becomes chronical. When the urinary lymphatics invert their motions, and pour their refluent contents into the bladder, some other branch of the absorbent system acts with greater energy to supply this fluid. If it is the intestinal branch, the chyliferous diabætes is produced: if it is the cutaneous or pulmonary branch, the aqueous diabætes is produced: and if the cellular or cystic branches, the mucaginous diabætes. In the two last the urine is pellucid, and contains no sugar. In dropsies the fluid is sometimes absorbed, and poured into the bladder by the retrograde motions of the urinary lymphatics, as during the exhibition of digitalis. In the beginning of the dropsies of infirm gouty patients, I have frequently observed, that they make a large quantity of water for one night, which relieves them for several days. In these cases the patient previously feels a fulness about the precordia, with difficult respiration, and symptoms similar to those of hysteria. Perhaps a previous defect of absorption takes place in some part of the body in those hysteric cases, which are relieved by a copious discharge of pale urine. See Diabætes explained at large, Section XXIX. 4. A discharge of blood sometimes attends the diabætes, which was occasionally a symptom of that disease in Mr. Brindley, the great navigable canal maker in this country. Which may be accounted for by the communication of a lymphatic branch with the gastric branch of the vena portarum, as discovered by J. F. Meckel. See Section XXVII. 2. M. M. Alum. Earth of Alum. Cantharides. Calomel. Bark. Steel. Rosin. Opium. See Sect. XXIX. 4. 7. _Sudor lymphaticus._ Profuse sweats from the inverted motions of the cutaneous lymphatics, as in some fainting fits, and at the approach of death; and as perhaps in the sudor anglicanus. See Sect. XXIX. 5. These sweats are glutinous to the touch, and without increased heat of the skin; if the part is not covered, the skin becomes cold from the evaporation of the fluid. These sweats without heat sometimes occur in the act of vomiting, as in Sect. XXV. 9. and are probably the cause of the cold sweaty hands of some people. As mentioned in Sect. XXIX. 4. 9. in the case of R. Davis, which he cured by frequent application of lime. Though it is possible, that cold sweaty hands may also arise from the want of due absorption of the perspirable matter effused on them, and that the coldness may be owing to the greater evaporation in consequence. The acid sweats described by Dr. Dobson, which he observed in a diabætic patient, and ascribes to the chyle effused on the skin, must be ascribed to the retrograde action of the cutaneous lymphatics. See Sect. XXIX. 6. 8. _Sudor asthmaticus._ The cold sweats in this disease only cover the head, arms, and breast, and are frequently exceedingly profuse. These sweats are owing to the inverted motions of the cutaneous lymphatics of the upper part of the body, and at the same time the increased absorption of the pulmonary absorbents: hence these sweats when profuse relieve the present fit of asthma. There is no other way to account for sweats appearing on the upper parts of the body only, but by the fluid having been absorbed by the lymphatic branch of the lungs, and effused on the skin by the retrograde movements of the cutaneous lymphatics; which join those of the lungs before they enter into the venous circulation. For if they were occasioned, as generally supposed, by the difficulty of the circulation of the blood through the lungs, the whole skin must be equally affected, both of the upper and lower parts of the body; for whatever could obstruct the circulation in the upper part of the venous system, must equally obstruct it in the lower part of it. See Sect. XXIX. 6. In the convulsive asthma these sweats do not occur; hence they may be distinguished; and might be called the hydropic asthma, and the epileptic asthma. 9. _Translatio puris._ Translation of matter from one part of the system to another can only be explained from its being absorbed by one branch of the lymphatic system, and deposited in a distant part by the retrograde motions of another branch; as mentioned Sect. XXIX. 7. 1. It is curious, that these translations of matter are attended generally, I believe, with cold fits; for less heat is produced during the retrograde action of this part of the system, as no secretion in the lymphatic glands of the affected branches can exist at the same time. Do any ineffectual retrograde motions occasion the cold fits of agues? The time when the gout of the liver ceases, and the gout in the foot commences, is attended with a cold fit, as I have observed in two instances, which is difficult to explain, without supposing the new vessels, or the matter produced on the inflamed liver, to be absorbed, and either eliminated by some retrograde motion, or carried to the newly inflamed part? See Class IV. 1. 2. 15. 10. _Translatio lactis._ Translation of milk to the bowels in puerperal fevers can only be explained by the milk being absorbed by the pectoral branch of lymphatics, and carried to the bowels by the retrograde motions of the intestinal lymphatics or lacteals. See many instances of this in Sect. XXIX. 7. 4. 11. _Translatio urinæ._ Translation of urine. There is a curious case related in the Transaction of the College of Physicians at Philadelphia, Vol. I. p. 96. of a girl, who labouring under an iscuria vomited her urine for many months; which could not be distinguished from that which was at other times drawn off by the catheter. After having taken much opium, she seems at length to have formed gravel, some of which was frequently brought up by vomiting. Dr. Senter ascribes this to the retrograde motions of the lymphatics of the stomach, and the increased ones of those of the bladder, and refers to those of Sect. XXIX. of this work; which section was first published in 1780; and to Macquire's Dictionary of Chemistry, Art. Urine. The patient above described sometimes had a discharge of urine by the navel, and at other times by the rectum, and sometimes by urinous sweats. * * * * * ORDO III. _Retrograde Irritative Motions._ GENUS III. _Of the Sanguiferous System._ SPECIES. 1. _Capillarium motus retrogressus._ In microscopic experiments it is usual to see globules of blood regurgitate from the capillary vessels again and again, before they pass through them; and not only the mouths of the veins, which arise from these capillaries, are frequently seen by microscopes to regurgitate some particles of blood during the struggles of the animal; but a retrograde motion of the blood in the veins of these animals, from the very heart to the extremities of the limbs, is observable by intervals during the distresses of the dying creature. Haller, Elem. Phys. T. i. p. 216. See Section XXIX. 3. 8. 2. _Palpitatio cordis._ May not the ineffectual and weak unequal motions of the heart in hysteric cases be ascribed to the retrograde motions of it, which continue for a short time, or terminate in syncope? See Class IV. 3. 1. 6. 3. _Anhelatio spasmodica._ In some asthmas may not the difficulty of respiration arise from the inverted action of the finer branches of the bronchia, or of the pulmonary artery or vein, like those of the capillaries above described in No. 1. of this genus? * * * * * _The Orders and Genera of the Second Class of Diseases._ * * * * * CLASS II. DISEASES OF SENSATION. ORDO I. _Increased Sensation._ GENERA. 1. With increased action of the muscles. 2. With the production of new vessels by internal membranes or glands with fever. 3. With the production of new vessels by external membranes or glands with fever. 4. With the production of new vessels by internal membranes or glands without fever. 5. With the production of new vessels by external membranes or glands without fever. 6. With fever consequent to the production of new vessels or fluids. 7. With increased action of the organs of sense. ORDO II. _Decreased Sensation._ GENERA. 1. With decreased actions of the general system. 2. With decreased actions of particular organs. ORDO III. _Retrograde Sensitive Motions._ GENERA. 1. Of the excretory ducts. * * * * * _The Orders, Genera, and Species, of the Second Class Of Diseases._ * * * * * CLASS II. DISEASES OF SENSATION. ORDO I. _Increased Sensation._ GENUS I. _With Increased Action of the Muscles._ SPECIES. 1. _Deglutitio._ Deglutition. 2. _Respiratio._ Respiration. 3. _Sternutatio._ Sneezing. 4. _Anhelitus._ Panting. 5. _Tussis ebriorum._ Cough of inebriates. 6. _Syngultus._ Hiccough. 7. _Asthma humorale._ Humoral asthma. 8. _Nictitatio sensitiva._ Winking from pain. 9. _Oscitatio et pandiculatio._ Yawning and stretching. 10. _Tenesmus._ Tenesmus. 11. _Stranguria._ Strangury. 12. _Parturitio._ Parturition. GENUS II. _With the Production of new Vessels by internal Membranes or Glands, with Fever._ SPECIES. 1. _Febris sensitiva irritata._ Sensitive irritated fever. 2. _Ophthalmia interna._ Inflammation of the eye. 3. _Phrenitis._ ---- of the brain. 4. _Peripneumonia._ ---- of the lungs. ---- _trachealis._ ---- the croup. 5. _Pleuritis._ ---- of the pleura. 6. _Diaphragmitis._ ---- of the diaphragm. 7. _Carditis._ ---- of the heart. 8. _Peritonitis._ ---- of the peritoneum. 9. _Mesenteritis._ ---- of the mesentery. 10. _Gastritis._ ---- of the stomach. 11. _Enteritis._ ---- of the bowels. 12. _Hepatitis._ ---- of the liver. 13. _Splenitis._ ---- of the spleen. 14. _Nephritis._ ---- of the kidney. 15. _Cystitis._ ---- of the bladder. 16. _Hysteritis._ ---- of the womb. 17. _Lumbago sensitiva._ ---- of the loins. 18. _Ischias._ ---- of the pelvis. 19. _Paronychia interna._ ---- beneath the nails. GENUS III. _With the Production of new Vessels by external Membranes or Glands, with Fever._ SPECIES. 1. _Febris sensitiva inirritata._ Sensitive inirritated fever. 2. _Erysipelas irritatum._ Erysipelas irritated. _----inirritatum._ ---- inirritated. ---- _sensitivum._ ---- sensitive. 3. _Tonsillitis interna._ Angina internal. ---- _superficialis._ ---- superficial. ---- _inirritata._ ---- inirritated. 4. _Parotitis suppurans._ Mumps suppurative. ---- _mutabilis._ ---- mutable. ---- _felina._ ---- of cats. 5. _Catarrhus sensitivus._ Catarrh inflammatory. 6. ---- _contagiosus._ ---- contagious. ---- _equinus et caninus._ ---- among horses and dogs. 7. _Peripneumonia superficialis._ Superficial peripneumony. 8. _Pertussis._ Chin-cough. 9. _Variola discreta._ Small-pox distinct. ---- _confluens._ ---- confluent. ---- _inoculata._ ---- inoculated. 10. _Rubeola irritata._ Measles irritated. ---- _inirritata._ ---- inirritated. 11. _Scarlatina mitis._ Scarlet fever mild. ---- _maligna._ ---- malignant. 12. _Miliaria sudatoria._ Miliary fever sudatory. ---- _irritata._ ---- irritated. ---- _inirritata._ ---- inirritated. 13. _Pestis._ Plague. ---- _vaccina._ ---- of horned cattle. 14. _Pemphigus._ Bladdery fever. 15. _Varicella._ Chicken-pox. 16. _Urticaria._ Nettle rash. 17. _Aptha sensitiva._ Thrush sensitive. ---- _irritata._ ---- irritated. ---- _inirritata._ ---- inirritated. 18. _Dysenteria._ Bloody flux. 19. _Gastritis superficialis._ Superficial inflam. of the stomach. 20. _Enteritis superficialis._ ---- of the bowels. GENUS IV. _With the Production of new Vessels by internal Membranes or Glands, without Fever._ SPECIES. 1. _Ophthalmia superficialis._ Ophthalmy superficial. ---- _lymphatica._ ---- lymphatic. ---- _equina._ ---- of horses. 2. _Pterigion._ Eye-wing. 3. _Tarsitis palpebrarum._ Red eyelids. 4. _Hordeolum._ Stye. 5. _Paronychia superficialis._ Whitlow. 6. _Gutta rosea hepatica._ Pimpled face hepatic. ---- _stomatica._ ---- stomatic. ---- _hereditaria._ ---- hereditary. 7. _Odontitis._ Inflamed tooth. 8. _Otitis._ ---- ear. 9. _Fistula lacrymalis._ Fistula lacrymalis. 10. _Fistula in ano._ Fistula in ano. 11. _Fistula urethræ._ Fistula urethræ. 12. _Hepatitis chronica._ Chronical hepatitis. 13. _Scrophula suppurans._ Suppurating scrophula. 14. _Scorbutus suppurans._ Suppurating scurvy. 15. _Schirrus suppurans._ Suppurating schirrus. 16. _Carcinoma._ Cancer. 17. _Arthrocele._ Swelling of the joints. 18. _Arthropuosis._ Suppuration of the joints. 19. _Caries ossium._ Caries of the bones. GENUS V. _With the Production of new Vessels by external Membranes or Glands, without Fever._ SPECIES. 1. _Gonorrhoea venerea._ Clap. 2. _Syphilis._ Venereal disease. 3. _Lepra._ Leprosy. 4. _Elephantiasis._ Elephantiasis. 5. _Framboesia._ Framboesia. 6. _Psora._ Itch. 7. _Psora ebriorum._ Itch of drunkards. 8. _Herpes._ Herpes. 9. _Zona ignea._ Shingles. 10. _Annulus repens._ Ring-worm. 11. _Tinea capitis._ Scald-head. 12. _Crusta lactea._ Milk-crust. 13. _Trichoma._ Plica polonica. GENUS VI. _With Fever consequent to the Production of new Vessels or Fluids._ SPECIES. 1. _Febris sensitiva._ Sensitive fever. 2. ---- _a pure clauso._ Fever from concealed matter. 3. ---- _a vomica._ ---- from vomica. 4. ---- _ab empyemate._ ---- from empyema. 5. ---- _mesenterica._ ---- mesenteric. 6. ---- _a pure aerato._ ---- from aerated matter. 7. ---- _a phthisi._ ---- from consumption. 8. ---- _scrophulosa._ ---- scrophulous. 9. ---- _ischiadica._ ---- from ischias. 10. ---- _arthropuodica._ ---- from joint-evil. 11. ---- _a pure contagioso._ ---- from contagious matter. 12. ---- _variolosa secundaria._ ---- secondary of small-pox. 13. ---- _carcinomatosa._ ---- cancarous. 14. ---- _venerea._ ---- venereal. 15. ---- _a sanie contagiosa._ ---- from contagious sanies. 16. ---- _puerpera._ ---- puerperal. 17. ---- _a sphacelo._ ---- from sphacelus. GENUS VII. _With increased Action of the Organs of Sense._ SPECIES. 1. _Delirium febrile._ Delirium of fevers. 2. ---- _maniacale._ ---- maniacal. 3. ---- _ebrietatis._ ---- of drunkenness. 4. _Somnium._ Dreams. 5. _Hallucinatio visûs._ Deception of sight. 6. ---- _auditus._ ---- of hearing. 7. _Rubor a calore._ Blush from heat. 8. ---- _jucunditatis._ ---- from joy. 9. _Priapismus amatorius._ Amorous priapism. 10. _Distentio mamularum._ Distention of the nipples. ORDO II. _Decreased Sensation._ GENUS I. _With decreased Action of the general System._ SPECIES. 1. _Stultitia insensibilis._ Folly from insensibility. 2. _Tædium vitæ._ Irksomeness of life. 3. _Paresis sensitiva._ Sensitive debility. GENUS II. _With decreased Actions of particular Organs._ SPECIES. 1. _Anorexia._ Want of appetite. 2. _Adipsia._ Want of thirst. 3. _Impotentia._ Impotence. 4. _Sterilitas._ Barrenness. 5. _Insensibilitas artuum._ Insensibility of the limbs. 6. _Dysuria insensitiva._ Insensibility of the bladder. 7. _Accumulatio alvina._ Accumulation of feces. ORDO III. _Retrograde Sensitive Motions._ GENUS I. _Of Excretory Ducts._ SPECIES. _Motus retrogressus_ Retrograde motion. 1. ---- _ureterum._ ---- of the ureters. 2. ---- _urethræ._ ---- of the urethra. 3. ---- _ductus choledoci._ ---- of the bile-duct. * * * * * CLASS II. DISEASES OF SENSATION. ORDO I. _Increased Sensation._ GENUS I. _With Increased Action of the Muscles._ The actions belonging to this genus are those which are immediately excited by the sensations of pain or pleasure, but which are neither followed by inflammation, nor by convulsion. The former of which belong to the subsequent genera of this order, and the latter to the class of voluntary motions. The criterion between the actions, which are the immediate consequence of painful sensation, and convulsive actions properly so called, consists in the former having a tendency to dislodge the stimulating cause, which induces the painful sensation; and the latter being exerted for the purpose of expending the sensorial power, and thus dulling or destroying the general sensation of the system. See Class III. 1. There is a degree of heat produced in the affected part by these sensitive actions without inflammation, but in much less quantity than when attended by inflammation; as in the latter there is a production of new vessels. See Sect. XXXIII. 2. 3. Some of the species of this genus cannot properly be termed diseases in their natural state, but become so by their defect or excess, and are here inserted to facilitate the explanation of the others. SPECIES. 1. _Deglutitio._ Swallowing our food is immediately caused by the pleasureable sensation occasioned by its stimulus on the palate or fauces and is acquired long before the nativity of the animal. Afterwards the pain of hunger previously produces the various voluntary exertions to procure the proper material, but the actions of masticating and of swallowing it are effected by the sensorial power of sensation; which appears by their not being always controulable by the will, as when children in vain attempt to swallow nauseous drugs. See Class IV. 1. 3. 1. The masticated food stimulates the palate, which is an organ of sense, into so much action, as to produce agreeable sensation; and the muscles subservient to deglutition are brought into action by the sensation thus produced. The pleasureable sensation is the proximate cause; the action of the fibres of the extremities of the nerves of taste is the remote cause; the sensorial power of irritation exciting these fibres of the nerves of taste into increased action is the pre-remote cause; the action of the muscles of deglutition is the proximate effect; the pushing the food into the stomach is the remote effect; and the nutrition of the body is the post-remote effect. Though the muscles subservient to deglutition have their actions previously associated, so as to be excited into synchronous tribes or successive trains, either by volition, as when we swallow a disagreeable drug; or by sensation, as when we swallow agreeable food; or by irritation, as when we inattentively swallow our saliva; yet do all those three kinds of deglutition belong to the respective classes of volition, sensation, and irritation; because the first links of these tribes or trains of muscular action are excited by those sensorial powers, and the associated links, which accompany or succeed them, are excited by the combined powers either of volition, or of sensation, or of irritation, along with that of association. 2. _Respiratio._ Respiration is immediately caused by the sensorial power of sensation in consequence of the baneful want of vital air; and not from the accumulation of blood in the lungs, as that might be carried on by inhaling azote alone, without the oxygenous part of the atmosphere. The action of respiration is thus similar to that of swallowing our food to appease the pain of hunger; but the lungs being surrounded with air, their proper pabulum, no intermediate voluntary exertions are required, as in hunger, to obtain and prepare the wanted material. Respiration is similar to slow combustion; the oxygenous part of the atmosphere is received through the moist membranes, which line the air-cells of the lungs, and uniting with the inflammable part of the blood generates an acid, probably the phosphoric acid; a portion of carbonic acid is likewise produced in this process; as appears by repeatedly breathing over lime-water, which then becomes turbid. See Botanic Garden, P. I. Canto I. l. 401. note. 3. _Sternutatio._ Sneezing consists of muscular actions produced by the sensorial faculty of sensation; and is an effort to dislodge, by means of air forcibly impelled through the nostrils, some material; which stimulates the membrane, which lines them, into too great action, and might thence injure the sense of smell which is diffused on it. In this operation the too great action of the vessels of the membrane of the nostrils is the remote cause; the sensation thence induced is the proximate cause; and the muscular actions are the proximate effect. This action of sneezing frequently precedes common respiration in new-born children, but I believe not always; as like the latter it cannot have been previously acquired in the uterus. It is produced in some people by sudden light, as by looking up at the sky in a morning, when they come out of a gloomy bed-chamber. It then becomes an associate action, and belongs to Class IV. 1. 2. 2. M. M. When it is exerted to excess it may be cured by snuffing starch up the nostrils. See Class I. 1. 2. 13. 4. _Anhelitus._ Panting. The quick and laborious breathing of running people, who are not accustomed to violent exercise, is occasioned by the too great conflux of blood to the lungs. As the sanguiferous system, as well as the absorbent system, is furnished in many parts of its course with valves, which in general prevent the retrograde movement of their contained fluids; and as all these vessels, in some part of their course, lie in contact with the muscles, which are brought into action in running, it follows that the blood must be accelerated by the intermitted swelling of the bellies of the muscles moving over them. The difficulty of breathing, with which, very fat people are immediately affected on exercise, is owing to the pressure of the accumulated fat on the veins, arteries, and lymphatics; and which, by distending the skin, occasions it to act as a tight bandage on the whole surface of the body. Hence when the muscles are excited into quicker action, the progress of the blood in the veins, and of the lymph and chyle in the absorbent system, is urged on with much greater force, as under an artificial bandage on a limb, explained in Art. IV. 2. 10. and in Sect. XXXIII. 3. 2. Hence the circulation is instantly quickened to a great degree, and the difficulty of breathing is the consequence of a more rapid circulation through the lungs. The increased secretion of the perspirable matter is another consequence of this rapid circulation; fat people, when at rest, are believed to perspire less than others, which may be gathered from their generally having more liquid stools, more and paler urine, and to their frequently taking less food than many thin people; and lastly, from the perspiration of fat people being generally more inodorous than that of lean ones; but when corpulent people are put in motion, the sweat stands in drops on their skins, and they "lard the ground" as they run. The increase of heat of corpulent people on exercise, is another consequence of their more rapid circulation, and greater secretion. See Class I. 2. 3. 17. Other causes of difficult or quick respiration will be treated of under Asthma, Pertussis, Peripneumony, Tonsillitis. 5. _Tussis ebriorum._ Sensitive cough is an exertion of the muscles used in expiration excited into more violent action by the sensorial power of sensation, in consequence of something which too powerfully stimulates the lungs. As the saline part of the secreted mucus, when the absorption of it is impeded; or the too great viscidity of it, when the absorption is increased; or the too great quantity of the mucus, when the secretion is increased; or the inflammation of the membranes of the lungs; it is an effort to dislodge any of these extraneous materials. Of this kind is the cough which attends free-drinkers after a debauch; it consists of many short efforts to cough, with a frequent expuition of half a tea-spoonful of frothy mucus, and is attended with considerable thirst. The thirst is occasioned by the previous dissipation of the aqueous parts of the blood by sensible or insensible perspiration; which was produced by the increased action of the cutaneous and pulmonary capillaries during the stimulus of the wine. In consequence of this an increased absorption commences to replace this moisture, and the skin and mouth become dry, and the pulmonary mucus becomes inspissated; which stimulates the bronchia, and is raised into froth by the successive currents of air in evacuating it. This production of froth is called by some free-drinkers "spitting sixpences" after a debauch. This subsequent thirst, dry mouth, and viscid expectoration in some people succeeds the slightest degree of intoxication, of which it may be esteemed a criterion. See Class IV. 2. 1. 8. As coughs are not always attended with pain, the muscular actions, which produce them, are sometimes excited by the sensorial faculty of irritation, as in Class I. 1. 2. 8. I. 1. 3. 4. I. 1. 4. 3. I. 2. 3. 4. Coughs are also sometimes convulsive, as in Class III. 1. 1. 10. and sometimes sympathetic, as Class IV. 2. 1. 7. M. M. Venesection, when the cough is attended with inflammation. Mucilages. Opium. Torpentia. Blister. 6. _Singultus._ Hiccough is an exertion of the muscles used in inspiration excited into more violent action by the sensorial power of sensation, in consequence of something which too powerfully stimulates the cardia ventriculi, or upper orifice of the stomach. As when solid food is too hastily taken without sufficient dilution. And is an effort to dislodge that offensive material, and push it to some less sensible part of the stomach, or into the middle of the contained aliment. At the end of fatal fevers it may arise from the acrimony of the undigested aliment, or from a part of the stomach being already dead, and by its weight or coldness affecting the surviving part with disagreeable sensation. The pain about the upper orifice of the stomach is the proximate cause, the too great or too little action of the fibres of this part of the stomach is the remote cause, the action of the muscles used in inspiration is the proximate effect, and the repercussion of the offending material is the remote effect. Hiccough is sometimes sympathetic, occasioned by the pain of gravel in the kidney or ureter, as in Class IV. 1. 1. 7. and is sometimes a symptom of epilepsy or reverie, as in Sect. XIX. 2. M. M. Oil of cinnamon from one drop gradually increased to ten, on sugar, or on chalk. Opium. Blister. Emetic. 7. _Asthma humorale._ The humoral asthma probably consists in a temporary anasarca of the lungs, which may be owing to a temporary defect of lymphatic absorption. Its cause is nevertheless at present very obscure, since a temporary deficiency of venous absorption, at the extremities of the pulmonary or bronchial veins, might occasion a similar difficulty of respiration. See Abortio, Class I. 2. 1. 14. Or it might be supposed, that the lymph effused into the cavity of the chest might, by some additional heat during sleep, acquire an aerial form, and thus compress the lungs; and on this circumstance the relief, which these patients receive from cold air, would be readily accounted for. The paroxysms attack the patient in his first sleep, when the circulation through the lungs in weak people wants the assistance of the voluntary power. Class I. 2. 1. 3. And hence the absorbents of the lungs are less able to fulfil the whole of their duty. And part of the thin mucus, which is secreted into the air-cells, remains there unabsorbed, and occasions the difficult respiration, which awakes the patient. And the violent exertions of the muscles of respiration, which succeed, are excited by the pain of suffocation, for the purpose of pushing forwards the blood through the compressed capillaries, and to promote the absorption of the effused lymph. In this the humoral differs from the convulsive asthma, treated of in Class III. 1. 1. 10. as in that there is probably no accumulated fluid to be absorbed; and the violent respiration is only an exertion for the purpose of relieving pain, either in the lungs or in some distant part, as in other convulsions, or epilepsy; and in this respect the fits of humoral and convulsive asthma essentially differ from each other, contrary to the opinion expressed without sufficient consideration in Sect. XVIII. 15. The patients in the paroxysms both of humoral and convulsive asthma find relief from cold air, as they generally rise out of bed, and open the window, and put out their heads; for the lungs are not sensible to cold, and the sense of suffocation is somewhat relieved by there being more oxygen contained in a given quantity of cold fresh air, than in the warm confined air of a close bed-chamber. I have seen humoral asthma terminate in confirmed anasarca, and destroy the patient, who had been an excessive drinker of spirituous potation. And M. Savage asserts, that this disease frequently terminates in diabetes; which seems to shew, that it is a temporary dropsy relieved by a great flow of urine. Add to this, that these paroxysms of the asthma are themselves relieved by profuse sweats of the upper parts of the body, as explained in Class I. 3. 2. 8. which would countenance the idea of their being occasioned by congestions of lymph in the lungs. The congestion of lymph in the lungs from the defective absorption of it is probably the remote cause of humoral asthma; but the pain of suffocation is the immediate cause of the violent exertions in the paroxysms. And whether this congestion of lymph in the air-cells of the lungs increases during our sleep, as above suggested, or not; the pain of suffocation will be more and more distressing after some hours of sleep, as the sensibility to internal stimuli increases during that time, as described in Sect. XVIII. 15. For the same reason many epileptic fits, and paroxysms of the gout, occur during sleep. In two gouty cases, complicated with jaundice, and pain, and sickness, the patients had each of them a shivering fit, like the commencement of an ague, to the great alarm of their friends; both which commenced in the night, I suppose during their sleep; and the consequence was a cessation of the jaundice, and pain about the stomach, and sickness; and instead of that the gout appeared in their extremities. In these cases I conjecture, that there was a metastasis not only of the diseased action from the membranes of the liver to those of the foot; but that some of the new vessels, or new fluids, which were previously produced in the inflamed liver, were translated to the feet during the cold fit, by the increased absorption of the hepatic lymphatics, and by the retrograde motions of those of the affected limbs. This I think resembles in some respects a fit of humoral asthma, where stronger motions of the absorbent vessels of the lungs are excited, and retrograde ones of the correspondent cutaneous lymphatics; whence the violent sweats of the upper parts of the body only are produced; and for a time the patient becomes relieved by the metastasis and elimination of the offending material by sensitive exertion. For a further account of this intricate subject see Class III. 1. 1. 10. M. M. To relieve the paroxysm a tea-spoonful of ether may be given mixed with water, with 10 drops of laudanum, to be repeated three or four times. Venesection. An emetic. A blister. Afterwards the Peruvian bark, with a grain of opium at night, and two or three of aloes. A flannel shirt in winter, but not in summer. Issues. Digitalis? In this species of asthma, there is great reason to believe, that the respiration of an atmosphere, with an increased proportion of oxygen, will prove of great advantage; some well-observed and well-attested cases of which are published by Dr. Beddoes; as this purer air invigorates the circulation, and the whole system in consequence, perhaps not only by its stimulus, but by its supplying the material from which the sensorial power is extracted or fabricated. In spasmodic asthma, on the contrary, Dr. Ferriar has found undoubted benefit from an atmosphere mixed with hydrogen. See Sect. XVIII. 15. and Class III. 1. 1. 10. 8. _Nictitatio sensitiva._ Winking of the eyes is performed every minute, without our attention, for the purpose of diffusing the tears over them, which are poured into the eye a little above the external corner of it, and which are afterwards absorbed by the lacrymal points above and below the internal corner of it. When this operation is performed without our attention, it is caused by the faculty of irritation, and belongs to Class I. 1. 4. 1. but when it is produced by a stronger stimulus of any extraneous material in the eye, so as to cause pain, the violent and frequent nictitation is caused by the faculty of sensation. This disease is sometimes produced by the introversion of the edge of the lower eyelid, which bends the points of the hairs of the eyelash upon the ball of the eye, which perpetually stimulate it into painful sensation. This introversion of the eyelid is generally owing to a tumor of the cellular membrane below the edge of the eyelid, and though a very troublesome complaint may often be cured by the following simple means. A little common plaster spread on thin linen, about a quarter of an inch long, must be rolled up so as to be about the size of a crow-quill, this must be applied immediately below the eyelash on the outside of the eye; and must be kept on by another plaster over it. This will then act as a slight compression on the tumor under the eyelash, and will prevent the hairs from touching the eye-ball. In a week or two the compression will diminish the tumor it lies over, and cure this painful deformity. 9. _Oscitatio et pandiculatio._ Yawning and stretching of the limbs is produced either by a long inactivity of the muscles now brought into action, as sometimes happens after sleep, or after listening a long time to a dull narrative; or it is produced by a too long continued action of the antagonist muscles. In the former case there is an accumulation of sensorial power during the quiescence of the muscles now brought into action; which probably constitutes the pain or wearisomeness of a continued attitude. In the latter case there is an exhaustion of sensorial power in the muscles, which have lately been acting violently, and a consequent accumulation in the muscles, which are antagonists to them, and which were at rest. These involuntary motions are often seen in paralytic limbs, which are at the same time completely disobedient to the will; and are frequently observable in very young children; and from thence we may conclude, that these motions are learnt before nativity; as puppies are seen to open their mouths before the membranes are broken. See Sect. XVI. 2. Where these motions are observed in limbs otherwise paralytic, it is an indication that electric shocks may be employed with advantage, as the excitability of the limb by irritation is not extinct, though it be disobedient both to volition and sensation. 10. _Tenesmus_ consists in violent and frequent ineffectual efforts to discharge the contents of the rectum, owing to pain of the sphincter. The pain is produced by indurated feces, or by some acrid material, as the acidity of indigested aliment; and the efforts are attended with mucus from the pained membrane. The feces must sometimes be taken away by the end of a marrow-spoon, as cathartics and even clyster will pass without removing them. It is sometimes caused by sympathy with the urethra, when there is a stone at the neck of the bladder. See Class II. 2. 2. 7. and IV. 1. 2. 8. M. M. Fomentation, an enema with mucilage and laudanum. The common exclusion of the feces from the rectum is a process similar to this, except that the muscles of the sphincter ani, and those of the abdomen, which act along with them by the combined powers of sensation and association, are in tenesmus excited by painful sensation, and in the latter by a sensation, which may in some instances be almost called pleasurable, as relieving us from a painful one in the exclusion of the feces. 11. _Stranguria._ Strangury consists in painful efforts to discharge the contents of the urinary bladder. It is generally owing to a stone in the sphincter of the bladder; or to the inflammation of the neck of it occasioned by cantharides. It is sometimes caused by sympathy with the piles; and then is liable in women to occasion convulsions, from the violence of the pain without inflammation. See Class IV. 2. 2. 2. and 3. M. M. Fomentation clyster with oil and laudanum, push the stone back with a bougie; if from cantharides give half a pint of warm water every ten minutes. Mucilage of gum arabic and tragacanth. The natural evacuation of the urine is a process similar to this, except that the muscular fibres of the bladder, and the muscles of the abdomen, which act in concert with them by the combined powers of sensation and of association, are, in the former case of strangury, excited into action by painful sensation; and in the latter by a sensation, which may almost be termed pleasurable, as it relieves us from a previous uneasy one. The ejectio feminis is another process in some respects similar to strangury, as belonging to the same sensible canal of the urethra, and by exciting into action the accelerator muscles; but in the strangury these muscles are excited into action by painful sensation, and in the ejection of the semen by pleasureable sensation. 12. _Parturitio._ Parturition is not a disease, it is a natural process, but is more frequently unfortunate in high life than amongst the middle class of females; which may be owing partly to fear, with which the priests of LUCINA are liable to inspire the ladies of fashion to induce them to lie in in town; and partly to the bad air of London, to which they purposely resort. There are however other causes, which render parturition more dangerous to the ladies of high life; such as their greater general debility from neglect of energetic exercise, their inexperience of the variations of cold and heat, and their seclusion from fresh air. To which must be added, that great source of the destruction of female grace and beauty, as well as of female health, the tight stays, and other bandages, with which they are generally tortured in their early years by the active folly of their friends, which by displacing many of the viscera impedes their actions, and by compressing them together produces adhesions of one part to another, and affects even the form and aperture of the bones of the pelvis, through which the nascent child must be protruded. As parturition is a natural, not a morbid process, no medicine should be given, where there is no appearance of disease. The absurd custom of giving a powerful opiate without indication to all women, as soon as they are delivered, is, I make no doubt, frequently attended with injurious, and sometimes with fatal consequences. See Class II. 1. 2. 16. Another thing very injurious to the child, is the tying and cutting the navel-string too soon; which should always be left till the child has not only repeatedly breathed, but till all pulsation in the cord ceases. As otherwise the child is much weaker than it ought to be; a part of the blood being left in the placenta, which ought to have been in the child; and at the same time the placenta does not so naturally collapse, and withdraw itself from the sides of the uterus, and is not therefore removed with so much safety and certainty. The folly of giving rue or rhubarb to new-born children, and the danger of feeding them with gruel instead of milk, is spoken of in Class I. 1. 2. 5. and II. 1. 2. 16. * * * * * ORDO I. _Increased Sensation._ GENUS II. _With the Production of new Vessels by internal Membranes or Glands, with Fever._ In the first class of diseases two kinds of fevers were described, one from excess, and the other from defect of irritation; and were in consequence termed irritative, and inirritative fevers. In this second class of diseases another kind of fever occurs, which is caused by excess of sensation, and termed in consequence Sensitive Fever. But there is no fever from defect of sensation, because the circulation is carried on in health without our consciousness, that is, without any sensation attending it. But as excess of sensation may exist with excess or defect of irritation, two other kinds of fever arise from a combination of sensitive fever with the irritative, and inirritative ones. Making five kinds in all. 1. Irritative fever, described in Class I. 1. 1. 1. 2. Inirritative fever. Class I. 2. 1. 1. 3. Sensitive fever. Class II. 1. 6. 1. 4. Sensitive irritated fever. Class II. 1. 2. 1. 5. Sensitive inirritated fever. Class II. 1. 3. 1. As the sensitive irritated fever attends all the diseases enumerated under the genus about to be described, it is placed at the head of it. And as the sensitive inirritated fever accompanies the greatest number of the species enumerated under the third genus of this order, it is placed at the head of them. And as the sensitive fever attends the diseases of the sixth genus, it is placed at the head of them. But as every febrile paroxysm consists of disordered tribes or trains of associated motions, it may be doubted, whether they ought not all to have been placed in the fourth class, amongst the diseases of association. See Class IV. 2. 4. 11. All the subsequent species of this genus are attended with sensitive irritated fever; there are nevertheless some superficial inflammations, which affect the same situations without much fever, as the scrophulous ophthalmy and spurious peripneumony, which belong to other genera. Inflammation is uniformly attended with the production or secretion of new fibres constituting new vessels; this therefore may be esteemed its essential character, or the criterion of its existence. The extension of the old vessels seems rather a consequence than a cause of the germination, or pullulation, of these new ones; for the old vessels may be enlarged, and excited with unusual energy, without any production of new ones, as in the blush of shame or of anger. When these new vessels are formed, if they are not reabsorbed into the circulation, they secrete a new fluid called purulent matter; which generally opens itself a passage on the external skin, and produces an ulcer, which either gradually heals, or spreads, and is the cause of hectic fever; or they secrete contagious matter, which has the property of exciting the same kind of inflammation, and of producing the same kind of contagious matter, when inserted by inoculation into the skin of other persons. These contagious matters form ulcers, which either heal spontaneously, or by art; or continue to spread, and destroy the patient, by other kinds of hectic fever. In this genus there is an increase of the sensorial power of irritation as well as of sensation; whence great arterial energy is produced, and the pulse becomes strong and full, as well as quick; and the coats of the arteries feel hard under the finger, being themselves thickened and distended by inflammation. The blood drawn, especially at the second bleeding, is covered with a tough size; which is probably the mucus from the inflamed internal surface of the arteries, increased in quantity, and more coagulable than in its natural state; the thinner part being more perfectly absorbed by the increased action of the inflamed absorbents. See Sect. XXXIII. 2. 2. This is rendered more probable, because the hard feel of the pulse, and the abundance of coagulable lymph commence, exist, and cease together. Great heat is produced from the new chemical combinations arising in the secretion of new fibres, and great pain from the distention of old ones, or from their increased action. The increased quantity of sensation from a topical inflammation or phlegmon is the immediate cause of the febris sensitiva irritata, or inflammatory fever; as when it arises from the pain of pleurisy, or paronychia; but generally an irritative fever precedes this topical inflammation, which occurs during the hot fit of it; and then the irritative fever is changed into a sensitive irritated fever, by the additional cause of the sensorial power of sensation besides that of irritation. SPECIES. 1. _Febris sensitiva irritata._ Sensitive irritated fever, or inflammatory fever. Phlegmasia. A strong full pulse, with inflammation of the coats of the arteries, constitutes this disease. It originates from some topical inflammation, which, if the fever is not subdued, terminates in suppuration; and differs from irritative fever in respect to the painful sensation which accompanies it. For as pleasurable sensation is the cause of the growth of the new vessels, and distention of the old ones, in the natural enlargement of the body during our infancy; so a painful sensation is the cause of the unnatural production of new vessels, and enlargement of old ones in inflammatory diseases. When matter is thus formed in any internal viscus, or in the cellular membrane, as in the lungs or liver; so long as this abscess remains without admission of air, this inflammatory fever is liable to continue, receiving only temporary relief by bleeding or emetics, or cathartics; till the patient, after a month, or two, or three, expires. But, if air be admitted to these internal abscesses, this kind of fever is changed into a hectic fever in a single day. It also sometimes happens, that when the abscess remains unopened to the air, if the matter has become putrid, that hectic fever supervenes, with colliquative sweats, or diarrhoea; the matter in both cases is sometimes absorbed, and the sides of the abscess grow together again without an external aperture. See Class II. 1. 4. 1. and 2. Another termination of inflammation is in gangrene, but this belongs to the inflammation of the external skin; as the production of purulent matter belongs to inflammation of the internal or mucous membranes. Thus when the external skin is the seat of inflammation, as in erythema, or erysipelas, and produces sensitive irritated fever, no collection of purulent matter can be formed; but a material oozes out, and lies upon the surface, like that in the confluent small-pox, and the cuticle at length peels off, or gangrene supervenes. It must be noted, that these kinds of inflammation can exist together; and some parts of the cellular membrane may suppurate at the same time that the external skin is affected with erythema, or erysipelas. M. M. Venesection. Cathartics. Diluents. Cool air. Torpentia. Cold Bath? See Sect. XII. 6. The increased arterial action in this sensitive irritated fever is not simply owing to the increased irritability of the arterial system, or to the stimulus of the distention of the vessels, but also to the increased acrimony or pungency of the blood; which has now so far changed its nature as to become more fluid, more dense, and to be loaded with coagulable lymph. Hence it becomes necessary not only to lessen the quantity of blood by venesection and by cathartics, but also to dilute its acrimony, or pungency, by the introduction of aqueous and mucilaginous fluids, such as barley water, cream and water, sugar and water, weak broths; to which may be added so much of some vegetable essential oil, as may render them grateful to the stomach, and thus promote their absorption, as by infusing parsley or cellery and turneps in the broth; or by balm, mint, or sage teas. The following species of this genus only distinguish the situation of the part previously inflamed, and which is the remote cause of the sensitive irritated, or inflammatory fever, which attends it. 2. _Ophthalmia interna._ Inflammation of the eye is attended with the production of new vessels, which spread over the tunica adjunctiva, and over the cornea; these new vessels are easily seen, as they lie on a white ground, and give ocular demonstration of their production in inflammation. When this inflammation of the cornea suppurates, it is liable to leave little ulcers, which may be seen beneath the surface in the form of little excavations; and as these heal, they are liable to be covered with an opake scar. This scar, in some months or years, is liable to wear away, and become transparent, without the assistance of any polishing powder, as of very finely levigated glass, as some have recommended. But when the cornea is affected through all its thickness, the return of its transparency becomes hopeless. See Class I. 1. 3. 14. In violent degrees of ophthalmy the internal parts, as the retina, optic artery, iris, ciliary process, become inflamed, as well as the external ones; hence the least light admitted to the eye occasions intolerable pain. This curious circumstance cannot be owing to the action of light on the inflamed vessels of the cornea; it therefore shews, that the extremity of the optic nerve or retina is also rendered more exquisitely sensible to light, by partaking of the inflammation; and I have been told, that red colours are in these cases sometimes painfully perceived even in perfect darkness. This shews that the retina is excited into motion by the stimulus of light; and that, when it is inflamed, these motions give great pain, like those of other inflamed parts, as the muscles, or membranes. And secondly, that the ideas of colours consist in the motions of the retina; which ideas occasion pain, when the extremity of the moving nerve is inflamed. M. M. Venesection. Cathartics. Diluents. Torpentia. Frequently moisten the eye with cold water by means of a rag. Cool airy room. Darkness. When the inflammation begins to decline, white vitriol gr. vi. in an ounce of water is more efficacious to moisten the eye than solutions of lead. Tincture of opium diluted. New vessels from the inflamed tunica adnata frequently spread like a fly's wing upon the transparent cornea, which is then called Pterigium. To stop the growth of this, the principal vessels should be cut through with a lancet. When the inflammation begins to decline, after due evacuation any stimulating material put into the eye increases the absorption, which soon removes the new red vessels; which has given rise to a hundred famous eye-waters, and eye-doctors; if these stimulating materials are used too soon, the inflammation is increased by them. See Sect. XXXII. 2. 10. There is another ophthalmia, which attends weak children, and is generally esteemed a symptom of scrophula, as described in Class II. 1. 4. 1. and another, which is of venereal origin, mentioned in Class II. 1. 5. 2. both which may be termed ophthalmia superficialis. 3. _Phrenitis._ Inflammation of the brain is attended with intolerance of light and sound; which shews, that the extremities of the nerves of those senses are at the same time inflamed; it is also attended with great pain of the head, with watchfulness, and furious delirium. The violent efforts, these patients are said sometimes to exert, are owing to the increased secretion of sensorial power in the brain; as all other inflamed glands have a greater circulation of blood passing through them, and a greater secretion in consequence of their peculiar fluids, as in the hepatitis much more bile is generated. M. M. Venesection. Cathartics. Torpentia. Foment the head with cold water for hours together. Or with warm water. Cool airy room. Afterwards cupping on the occiput. Leeches to the temples. When the patient is weakened a blister on the head, and after further exhaustion five or six drops of tincture of opium. 4. _Peripneumonia._ Inflammation of the lungs. The pulse is not always hard, sometimes soft; which is probably owing to a degree of sickness or inaction of the stomach; with dull pain of the chest; respiration constantly difficult, sometimes with erect posture; the face bloated and purplish; cough generally with moist expectoration, often stained with blood. When the difficulty of respiration is very great, the patient is not able to cough; in this situation, after copious bleeding, the cough is liable to return, and is so far a favourable symptom, as it shews some abatement of the inflammation. A peripneumony frequently occurs in the chin-cough, and destroys the patient, except immediate recourse be had to the lancet, or to four or five leeches; when blood cannot be otherwise taken. The peripneumony is very fatal to young children, especially as I believe it is frequently mistaken for a spasmodic asthma, or for the croup, or cynanche trachealis of Cullen. Both which, however, when they occur, require immediate venesection by the lancet or by leeches, as well as the peripneumony. The croup is an inflammation of the upper part, and the peripneumony of the lower part of the same organ, viz. the trachea or windpipe. See Class I. 1. 3. 4. But as the inflammation is seldom I suppose confined to the upper part of the trachea only, but exists at the same time in other parts of the lungs, and as no inflammation of the tonsils is generally perceptible, the uncouth name of cynanche trachealis should be changed for _peripneumonia trachialis_. The method of cure consists in immediate and repeated bleeding. A vomit. A grain of calomel or other mild cathartic. Bathing in subtepid water, and in breathing over the steam of warm water, with or without a little vinegar in it. And lastly, by keeping the child raised high in bed. Inflammation of the lungs is also liable to occur in the measles, and must be attacked by venesection at any time of the disease; otherwise either a present death, or an incurable consumption, is the consequence. The peripneumony is frequently combined with inflammation of the pleura, and sometimes with that of the diaphragm; either of these may generally be distinguished, not only by the pain which attends inflammation of these membranes, but by inspecting the naked chest, and observing whether the patient breathes more by elevating the ribs, or by depressing the diaphragm. A crisis happens in children about the sixth day with much pale urine, which must be waited for after evacuations have been used, as far as can be done with safety; in this situation the warm bath twice a day, and small blisters repeatedly in succession, are of peculiar service. After the termination of peripneumony a collection of coagulable lymph is frequently left in the cavity of the chest unabsorbed; or a common anasarca of the lungs occurs from the present inaction of the absorbent vessels, which had previously been excited too violently. This difficulty of breathing is cured or relieved by the exhibition of digitalis. See Art. IV. 2. 8. M. M. The lancet is the anchor of hope in this disease; which must be repeated four or five times, or as often as the fever and difficulty of breathing increase, which is generally in the evening; antimonials, diluents, repeated small blisters about the chest, mucilage, pediluvium, warm bath. Is a decoction of seneka-root of use? Do not neutral salts increase the tendency to cough by their stimulus, as they increase the heat of urine in gonorrhoea? Children in every kind of difficult breathing, from whatever cause, should be kept as upright in bed as may be, and continually watched; since, if they slip down, they are liable to be immediately suffocated. After the patient is greatly debilitated, so that no further evacuation can be admitted, and the difficult breathing and cough continue, I have given four or five drops of tincture of opium, that is, about a quarter of a grain of solid opium, with great advantage, and I believe in several cases I have saved the patient. A greater quantity of opium in this state of debility cannot be used without hazarding the life of the person. This small quantity of an opiate should be given about six in the evening, or before the access of the evening paroxysm, and repeated three or four nights, or longer. There is a peripneumony with weak pulse, which may be termed _peripneumonia inirritata_, as described in Sect. XXVII. 2. which belongs to this place. See also Superficial Peripneumony, Class II. 1. 3. 7. 5. _Pleuritis._ Pleurisy. Inflammation of the pleura, with hard pulse, pain chiefly of the side, pungent, particularly increased during inspiration; lying on either side uneasy, the cough very painful, dry at the beginning, afterwards moist, often bloody. One cause of pleurisy is probably a previous adhesion of the lungs to a part of the pleura, which envelops them. This in many cases has been produced in infancy, by suffering children to lie too long on one side. Or by placing them uniformly on one side of a fire, or window, to which they will be liable always to bend themselves. When matter is produced during peripneumony or pleurisy in one side of the chest, so long as it is a concealed vomica, the fever continues, if the disease be great, for many weeks, and even months; and requires occasional venesection, till the patient sinks under the inflammatory or sensitive irritated fever. But if air be admitted, by a part of the abscess opening itself a way into the air-vessels of the lungs, a hectic fever, with colliquitive sweats or diarrhoea, supervenes, and frequently destroys the patient; or the abscess heals the lungs adhering to the pleura. M. M. The lancet must be used copiously, and repeated as often as the pain and difficult respiration increase. A blister on the pained part. Antimonial preparations. Diluents. Cool air. Do neutral salts increase the tendency to cough? Pediluvium or semicupium frequently repeated. 6. _Diaphragmitis._ Inflammation of the diaphragm. Pain round the lower ribs as if girt with a cord. Difficult respiration performed only by elevating the ribs and in an erect posture. The corners of the mouth frequently retracted into a disagreeable smile, called risus Sardonicus. Those animals, which are furnished with clavicles, or collar-bones, not only use their foremost feet as hands, as men, monkies, cats, mice, squirrels, &c. but elevate their ribs in respiration as well as depress the diaphragm for the purpose of enlarging the cavity of the chest. Hence an inflammation of the diaphragm is sudden death to those animals, as horses and dogs, which can only breaths by depressing the diaphragm; and is I suppose the cause of the sudden death of horses that are over-worked; whereas, in the human animal, when the diaphragm is inflamed, so as to render its motions impossible from the pain they occasion, respiration can be carried on, though in a less perfect manner, by the intercostal muscles in the elevation of the ribs. In pleurisy the ribs are kept motionless, and the respiration is performed by the diaphragm, as may be readily seen on inspecting the naked chest, and which is generally a bad symptom; in the diaphragmitis the ribs are alternately elevated, and depressed, but the lower part of the belly is not seen to move. M. M. As in pleurisy and peripneumony. When the patient becomes delirious, and smiles disagreeably by intervals, and is become so weak, that evacuations by the lancet could be used no further, and I have almost despaired of my patient, I have found in two or three instances, that about five or six drops of tinct. thebaic, given an hour before the evening exacerbation, has had the happiest effect, and cured the patient in this case, as well as in common peripneumony; it must be repeated two or three evenings, see Class II. 1. 2. 4. as the exacerbation of the fever and difficult respiration and delirium generally increase towards night. The stimulus of this small quantity of opium on a patient previously so much debilitated, acts by increasing the exertion of the absorbent vessels, in the same manner as a solution of opium, or any other stimulant, put on an inflamed eye after the vessels are previously emptied by evacuations, stimulates the absorbent system, so as to cause the remaining new vessels to be immediately reabsorbed. Which same stimulants would have increased the inflammation, if they had been applied before the evacuations. See Class II. 1. 2. 2. Sect. XXXIII. 3. 1. When the sanguiferous system is full of blood, the absorbents cannot act so powerfully, as the progress of their contents is opposed by the previous fulness of the blood-vessels; whence stimulants in that case increase the action of the secerning system more than of the absorbent one; but after copious evacuation this resistance to the progress of the absorbed fluids is removed; and when stimulants are then applied, they increase the action of the absorbent system more than that of the secerning one. Hence opium given in the commencement of inflammatory diseases destroys the patient; and cures them, if given in very small doses at the end of inflammatory diseases. 7. _Carditis._ Inflammation of the heart is attended with unequal intermitting pulse, palpitation, pain in the middle of the sternum, and constant vomiting. It cannot certainly be distinguished from peripneumony, and is perhaps always combined with it. 8. _Peritonitis._ Inflammation of the peritonæum is known by pain all over the abdomen, which is increased on erecting the body. It has probably most frequently a rheumatic origin. See Class II. 1. 2. 17. 9. _Mesenteritis._ Inflammation of the mesentery is attended with pains like colic, and with curdled or chyle-like stools. It is a very frequent and dangerous disease, as the production of matter more readily takes place in it than in any other viscus. The consequence of which, after a hard labour, is probably the puerperal fever, and in scrophulous habits a fatal purulent fever, or hopeless consumption. M. M. Venesection. Warm bath. Emollient clysters. 10. _Gastritis._ In inflammation of the stomach the pulse is generally soft, probably occasioned by the sickness which attends it. The pain and heat of the stomach is increased by whatever is swallowed, with immediate rejection of it. Hiccough. This disease may be occasioned by acrid or indigestible matters taken into the stomach, which may chemically or mechanically injure its interior coat. There is however a slighter species of inflammation of this viscus, and perhaps of all others, which is unattended by much fever; and which is sometimes induced by drinking cold water, or eating cold insipid food, as raw turnips, when the person has been much heated and fatigued by exercise. For when the sensorial power has been diminished by great exertion, and the stomach has become less irritable by having been previously stimulated by much heat, it sooner becomes quiescent by the application of cold. In consequence of this slight inflammation of the stomach an eruption of the face frequently ensues by the sensitive association of this viscus with the skin, which is called a surfeit. See Class IV. 1. 2. 13. and II. 1. 4. 6. and II. 1. 3. 19. M. M. Venesection. Warm bath. Blister. Anodyne clysters. Almond soap. See Class II. 1. 3. 17. 11. _Enteritis._ Inflammation of the bowels is often attended with soft pulse, probably owing to the concomitant sickness; which prevents sometimes the early use of the lancet, to the destruction of the patient. At other times it is attended with strong and full pulse like other inflammations of internal membranes. Can the seat of the disease being higher or lower in the intestinal canal, that is, above or below the valve of the colon, produce this difference of pulse by the greater sympathy of one part of the bowels with the stomach than another? In enteritis with strong pulse the pain is great about the navel, with vomiting, and the greatest difficulty in procuring a stool. In the other, the pain and fever is less, without vomiting, and with diarrhoea. Whence it appears, that the enteritis with hard quick pulse differs from Ileus, described in Class I. 3. 1. 6. only in the existence of fever in the former and not the latter, the other symptoms generally corresponding; and, secondly, that the enteritis with softer quick pulse, differs from the cholera described in Class I. 3. 1. 5. only in the existence of fever in the former, and not the latter, the other symptoms being in general similar. See Class II. 1. 3. 20. Inflammation of the bowels sometimes is owing to extraneous indigestible substances, as plum-stones, especially of the damasin, which has sharp ends. Sometimes to an introsusception of one part of the intestine into another, and very frequently to a strangulated hernia or rupture. In respect to the first, I knew an instance where a damasin stone, after a long period of time, found its way out of the body near the groin. I knew another child, who vomited some damasin stones, which had lain for near twenty hours, and given great pain about the navel, by the exhibition of an emetic given in repeated doses for about an hour. The swallowing of plum-stones in large quantities, and even of cherry-stones, is annually fatal to many children. In respect to the introsusception and hernia, see Ileus, Class I. 3. 1. 6. M. M. Repeated venesection. Calomel from ten to twenty grains given in small pills as in Ileus; these means used early in the disease generally succeed. After these evacuations a blister contributes to stop the vomiting. Warm bath. Crude mercury. Aloes one grain-pill every hour will frequently stay in the stomach. Glauber's salt dissolved in pepper-mint water given by repeated spoonfuls. When the patient is much reduced, opium in very small doses may be given, as a quarter of a grain, as recommended in pleurisy. If the pain suddenly ceases, and the patient continues to vomit up whatever is given him, it is generally fatal; as it indicates, that a mortification of the bowel is already formed. Some authors have advised to join cathartic medicines with an opiate in inflammation of the bowels, as recommended in colica saturnina. This may succeed in slighter cases, but is a dangerous practice in general; since, if the obstruction be not removed by the evacuation, the stimulus of the opium is liable to increase the action of the vessels, and produce mortification of the bowel, as I think I have seen more than once. 12. _Hepatitis._ Inflammation of the liver is attended with strong quick pulse; tension and pain of the right side; often pungent as in pleurisy, oftner dull. A pain is said to affect the clavicle, and top of the right shoulder; with difficulty in lying on the left side; difficult respiration; dry cough; vomiting; hiccough. There is another hepatitis mentioned by authors, in which the fever, and other symptoms, are wanting, or are less violent; as described in Class II. 1. 4. 12. and which is probably sometimes relieved by eruptions of the face; as in those who are habituated to the intemperate use of fermented liquors. M. M. Hepatic inflammation is very liable to terminate in suppuration, and the patient is destroyed by the continuance of a fever with sizy blood, but without night-sweats, or diarrhoea, as in other unopened abscesses. Whence copious and repeated venesection is required early in the disease, with repeated doses of calomel, and cathartics. Warm bath. Towards the end of the disease small doses of opium before the evening paroxysms, and lastly the Peruvian bark, and chalybeate wine, at first in small doses, as 20 drops twice a day, and afterwards, if necessary, in larger. See Art. IV. 2. 6. Mrs. C. a lady in the last month of her pregnancy, was seized with violent hepatitis, with symptoms both of peripneumony and of pleurisy, for it seldom happens in violent inflammations, that one viscus alone is affected; she wanted then about a fortnight of her delivery, and after frequent venesection, with gentle cathartics, with fomentation or warm bath, she recovered and was safely delivered, and both herself and child did well. Rheumatic and eruptive fevers are more liable to induce abortion. 13. _Splenitis._ Inflammation of the spleen commences with tension, heat, and tumour of the left side, and with pain, which is increased by pressure. A case is described in Class I. 2. 3. 18. where a tumid spleen, attended with fever, terminated in schirrus of that viscus. 14. _Nephritis._ Inflammation of the kidney seems to be of two kinds; each of them attended with different symptoms, and different modes of termination. One of them I suppose to be an inflammation of the external membrane of the kidney, arising from general causes of inflammation, and accompanied with pain in the loins without vomiting; and the other to consist in an inflammation of the interior parts of the kidney, occasioned by the stimulus of gravel in the pelvis of it, which is attended with perpetual vomiting, with pain along the course of the ureter, and retraction of the testis on that side, or numbness of the thigh. The former of these kinds of nephritis is distinguished from lumbago by its situation being more exactly on the region of the kidney, and by its not being extended beyond that part; after three or four days I believe this inflammation is liable to change place; and that a herpes or erysipelas, called zona, or shingles, breaks out about the loins in its stead; at other times it is cured by a cathartic with calomel, with or without previous venesection. The other kind of nephritis, or inflammation of the interior part of the kidney, generally arises from the pain occasioned by the stimulus of a stone entering the ureter from the pelvis of the kidney; and, which ceases when the stone is protruded forwards into the bladder; or when it is returned into the pelvis of the kidney by the retrograde action of the ureter. The kidney is nevertheless inflamed more frequently, though in a less degree, from other causes; especially from the intemperate ingurgitation of ale, or other fermented or spirituous liquors. This less degree of inflammation is the cause of gravel, as that before mentioned is the effect of it. The mucus secreted to lubricate the internal surface of the uriniferous tubes of the kidney becomes secreted in greater quantity, when these vessels are inflamed; and, as the correspondent absorbent vessels act more energetically at the same time, the absorption of its more fluid parts is more powerfully effected; on both these accounts the mucus becomes both changed in quality and more indurated. And in this manner stones are produced on almost every mucous membrane of the body; as in the lungs, bowels, and even in the pericordium, as some writers have affirmed. See Class I. 1. 3. 9. M. M. Venesection. Ten grains of calomel given in small pills, then infusion of sena with oil. Warm bath. Then opium a grain and half. See Class I. 1. 3. 9. for a further account of the method of cure. 15. _Cystitis._ Inflammation of the bladder is attended with tumor and pain of the lower part of the belly; with difficult and painful micturition; and tenesmus. It generally is produced by the existence of a large stone in the bladder, when in a great degree; or is produced by common causes, when in a slighter degree. The stone in the bladder is generally formed in the kidney, and passing down the ureter into the bladder becomes there gradually increased in size; and this most frequently by the apposition of concentric spheres, as may be seen by sawing some of the harder calculi through the middle, and polishing one surface. These new concretions superinduced on the nucleus, which descended from the kidney, as described in Class I. 1. 3. 9. and in the preceding article of this genus, is not owing to the microcosmic salt, which is often seen to adhere to the sides of chamber-pots, as this is soluble in warm water, but to the mucus of the bladder, as it rolls along the internal surface of it. Now when the bladder is slightly inflamed, this mucus of its internal surface is secreted in greater quantity, and is more indurated by the absorption of its more liquid part at the instant of secretion, as explained in Class I. 1. 3. 9. and II. 1. 2. 14. and thus the stimulus and pain of a stone in the bladder contributes to its enlargement by inflaming the interior coat of it. M. M. Venesection. Warm bath. Diluents. Anodyne clysters. See Class I. 1. 3. 9. 16. _Hysteritis._ Inflammation of the womb is accompanied with heat, tension, tumor, and pain of the lower belly. The os uteri painful to the touch. Vomiting. This disease is generally produced by improper management in the delivery of pregnant women. I knew an unfortunate case, where the placenta was left till the next day; and then an unskilful accoucheur introduced his hand, and forcibly tore it away; the consequence was a most violent inflammatory fever, with hard throbbing pulse, great pain, very sizy blood, and the death of the patient. Some accoucheurs have had a practice of introducing their hand into the uterus immediately after the birth of the child, to take away the placenta; which they said was to save time. Many women I believe have been victims to this unnatural practice. Others have received injury, where inflammation has been beginning, by the universal practice of giving a large dose of opium immediately on delivery, without any indication of its propriety; which, though a proper and useful medicine, where the patient is too feeble, when given in a small dose, as 10 drops of tincture of opium, or half a grain of solid opium, must do a proportionate injury, when it is given improperly; and as delivery is a natural process, it is certainly more wise to give no medicines, except there be some morbid symptom, which requires it; and which has only been introduced into custom by the ill-employed activity of the Priests or Priestesses of LUCINA; like the concomitant nonsense of cramming rue or rheubarb into the mouth of the unfortunate young stranger, who is thus soon made to experience the evils of life. See Class II. 1. 1. 12. and I. 1. 2. 5. Just so some over-wise beldames force young ducks and turkeys, as soon as they are hatched, to swallow a peppercorn. M. M. Venesection repeatedly; diluents; fomentation; the patient should be frequently raised up in bed for a short time, to give opportunity of discharge to the putrid lochia; mucilaginous clysters. See Febris Puerpera. 17. _Lumbago sensitiva._ Sensitive lumbago. When the extensive membranes, or ligaments, which cover the muscles of the back are torpid, as in the cold paroxysm of ague, they are attended with pain in consequence of the inaction of the vessels, which compose them. When this inaction continues without a consequent renewal or increase of activity, the disease becomes chronical, and forms the lumbago frigida, or irritativa, described in Class I. 2. 4. 16. But when this cold fit or torpor of these membranes, or ligaments or muscles of the back, is succeeded by a hot fit, and consequent inflammation, a violent inflammatory fever, with great pain, occurs, preventing the erect posture of the body; and the affected part is liable to suppurate, in which case a very dangerous ulcer is formed, and a part of one of the vertebrae is generally found carious, and the patient sinks after a long time under the hectic fever occasioned by the aerated or oxygenated matter. This disease bears no greater analogy to rheumatism than the inflammation of the pleura, or any other membranous inflammation; and has therefore unjustly been arranged under that name. It is distinguished from nephritis, as it is seldom attended with vomiting, I suppose never, except the ureter happens to be inflamed at the same time. The pain sometimes extends on the outside of the thigh from the hip to the ankle, heel, or toes, and is then called sciatica; and has been thought to consist in an inflammation of the theca, or covering of the sciatic nerve, as the pain sometimes so exactly attends the principal branches of that nerve. See Class I. 2. 4. 15. 16. M. M. Venesection repeatedly; calomel; gentle cathartics; diluents; warm bath; poultice on the back, consisting of camomile flowers, turpentine, soap, and opium; a burgundy-pitch plaster. A debility of the inferior limbs from the torpor of the muscles, which had previously been too much excited, frequently occurs at the end of this disease; in this case electricity, and issues on each side of the lumber vertebræ, are recommended. See Class I. 2. 4. 16. 18. _Ischias._ The ischias consists of inflammatory fever, with great pain about the pelvis, the os coccigis, and the heads of the thigh-bones, preventing the patient from walking or standing erect, with increase of pain on going to stool. This malady, as well as the preceding, has been ascribed to rheumatism; with which it seems to bear no greater analogy, than the inflammations of any other membranes. The patients are left feeble, and sometimes lame after this disease; which is also sometimes accompanied with great flow of urine, owing to the defective absorption of its aqueous parts; and with consequent thirst occasioned by the want of so much fluid being returned into the circulation; a lodgment of fæces in the rectum sometimes occurs after this complaint from the lessened sensibility of it. See Class I. 2. 4. 15. M. M. Venesection; gentle cathartics; diluents; fomentation; poultice with camomile flowers, turpentine, soap, and opium; afterwards the bark. See Class I. 1. 3. 5. When this inflammation terminates in suppuration the matter generally can be felt to fluctuate in the groin, or near the top of the thigh. In this circumstance, my friend Mr. Bent, Surgeon near Newcastle in Staffordshire, proposes to tap the abscess by means of a trocar, and thus as often as necessary to discharge the matter without admitting the air. Might a weak injection of wine and water, as in the hydrocele, be used with great caution to inflame the walls of the abscess, and cause them to unite? See Class II. 1. 6. 9. 19. _Paronychia interna._ Inflammation beneath the finger-nail. The pain occasioned by the inflammatory action and tumor of parts bound down between the nail on one side and the bone on the other, neither of which will yield, is said to occasion so much pain as to produce immediate delirium, and even death, except the parts are divided by a deep incision; which must pass quite through the periosteum, as the inflammation is said generally to exist beneath it. This disease is thus resembled by the process of toothing in young children; where an extraneous body lodged beneath the periosteum induces pain and fever, and sometimes delirium, and requires to be set at liberty, by the lancet. * * * * * ORDO I. _Increased Sensation._ GENUS III. _With the Production of new Vessels by external Membranes or Glands with Fever._ The diseases of this genus are perhaps all productive of contagious matter; or which becomes so by its exposure to the air, either through the cuticle, or by immediate contact with it; such are the matters of the small-pox and measles. The purulent matter formed on parts covered from the air by thicker membranes or muscles, as in the preceding genus, does not induce fever, and cannot therefore be called contagious; but it acquires this property of producing fever in a few hours, after the abscess has been opened, so as to admit the air to its surface, and may then be said to consist of contagious miasmata. This kind of contagious matter only induces fever, but does not produce other matter with properties similar to its own; and in this respect it differs from the contagious miasmata of small-pox or measles, but resembles those which have their origin in crowded jails; for these produce fever only, which frequently destroys the patient; but do not produce other matters similar to themselves; as appears from none of those, who died of the jail-fever, caught at the famous black assizes at Oxford, at the beginning of this century, having infected their physicians or attendants. If indeed the matter has continued so long as to become putrid, and thus to have given out air from a part of it, it acquires the power of producing fever; in the same manner as if the ulcer had been opened, and exposed to the common air; instances of which are not unfrequent. And from these circumstances it seems probable, that the matters secreted by the new vessels formed in all kinds of phlegmons, or pustles, are not contagious, till they have acquired something from the atmosphere, or from the gas produced by putrefaction; which will account for some phenomena in the lues venerea, cancer, and of other contagious secretions on the skin without fever, to be mentioned hereafter. See Class II. 1. 4. 14. The theory of contagion has been perplexed by comparing it with fermenting liquors; but the contagious material is shewn in Section XXXIII. to be produced like other secreted matters by certain animal motions of the terminations of the vessels. Hence a new kind of gland is formed at the terminations of the vessels in the eruptions of the small-pox; the animal motions of which produce from the blood variolous matter; as other glands produce bile or saliva. Now if some of this matter is introduced beneath the cuticle of a healthy person, or enters the circulation, and excites the extremities of the blood-vessels into those kinds of diseased motions, by which it was itself produced, either by irritation or association, these diseased motions of the extremities of the vessels will produce other similar contagious matter. See Sect. XXXIII. 2. 5. and 9. Hence contagion seems to be propagated two ways; one, by the stimulus of contagious matter applied to the part, which by an unknown law of nature excites the stimulated vessels to produce a similar matter; as in venereal ulcers, which thus continue to spread; or as when variolous matter is inserted beneath the cuticle; or when it is supposed to be absorbed, and diffused over the body mixed with the blood, and applied in that manner to the cutaneous glands. The other way, by which contagion seems to be diffused, is by some distant parts sympathizing or imitating the motions of the part first affected; as the stomach and skin in the eruptions of the inoculated small-pox, or in the bite of a mad dog; as treated of in Sect. XXII. 3. 3. In some of the diseases of this genus the pulse is strong, full, and hard, constituting the sensitive irritated fever, as described in the preceding genus; as in one kind of erysipelas, which requires repeated venesection. In others the arterial action is sometimes moderate, so as to constitute the sensitive fever, as in the inoculated small-pox; where the action of the arteries is neither increased by the sensorial power of irritation, as in the sensitive irritated fever; nor decreased by the defect of that power, as in the sensitive inirritated fever. But in the greatest number of the diseases of this genus the arterial action is greatly diminished in respect to strength, and consequently the frequency of pulsation is proportionally increased, as explained in Sect XXXII. 2. 1. Which is owing to the deficiency of the sensorial power of irritation joined with the increase of that of sensation, and thus constitutes the sensitive inirritated fever; as in Scarlatina with gangrenous tonsils. From this great debility of the action of the arteries, there appears to be less of the coagulable lymph or mucus secreted on their internal surfaces; whence there is not only a defect of that buff or size upon the blood, which is seen on the surface of that, which is drawn in the sensitive irritated fever; but the blood, as it cools, when it has been drawn into a bason, scarcely coagulates; and is said to be dissolved, and is by some supposed to be in a state of actual putrefaction. See Sect. XXXIII. 1. 3. where the truth of this idea is controverted. But in the fevers of both this genus and the preceding one great heat is produced from the chemical combinations in the secretions of new vessels and fluids, and pain or uneasiness from the distention of the old ones; till towards the termination of the disease sensation ceases, as well as irritation, with the mortification of the affected parts, and the death of the patient. Dysenteria, as well as tonsillitis and aphtha, are enumerated amongst the diseases of external membranes, because they are exposed either to the atmospheric air, which is breathed, and swallowed with our food and saliva; or they are exposed to the inflammable air; or hydrogen, which is generated in the intestines; both which contribute to produce or promote the contagious quality of these fluids; as mentioned in Class II. 1. 5. It is not speaking accurate language, if we say, that in the diseases of this genus the fever is contagious; since it is the material produced by the external membranes, which is contagious, after it has been exposed to air; while the fever is the consequence of this contagious matter, and not the cause of it. As appears from the inoculated small-pox, in which the fever does not commence, till after suppuration has taken place in the inoculated arm, and from the diseases of the fifth genus of this order, where contagion exists without fever. See Class II. 1. 5. and II. 1. 3. 18. SPECIES. 1. _Febris sensitiva inirritata._ Sensitive inirritated fever. Typhus gravior. Putrid malignant fever. Jail fever. The immediate cause of this disease is the increase of the sensorial power of sensation, joined with the decrease of the sensorial power of irritation; that is, it consists in the febris sensitiva joined with the febris inirritativa of Class I. 2. 1. 1. as the febris sensitiva irritata of the preceding genus consists of the febris sensitiva joined with the febris irritativa of Class I. 1. 1. 1. In both which the word irritata, and inirritata, are designed to express more or less irritation than the natural quantity; and the same when applied to some of the diseases of this genus. This fever is frequently accompanied with topical inflammation, which is liable, if the arterial strength is not supported, to end in sphacelus; and as mortified parts, such as sloughs of the throat, if they adhere to living parts, soon become putrid from the warmth and moisture of their situation; these fevers have been termed putrid, and have been thought to owe their cause to what is only their consequence. In hot climates this fever is frequently induced by the exhalations of stagnating lakes or marshes, which abound with animal substances; but which in colder countries produce fevers with debility only, as the quartan ague, without inflammation. The sensitive inirritated, or malignant, fever is also frequently produced by the putrid exhalations and stagnant air in prisons; but perhaps most frequently by contact or near approach of the persons, who have resided in them. These causes of malignant fevers contributed to produce, and to support for a while, the septic and antiseptic theory of them; see Sect. XXXIII. 1. 3. The vibices or bruises, and petechiæ or purples, were believed to be owing to the dissolved state of the blood by its incipient putrefaction; but hydrostatical experiments have been made, which shew the sizy blood of the patient in sensitive irritated or inflammatory fever, with strong pulse, is more fluid, while it is warm, than this uncoagulable blood taken in this sensitive inirritated, or malignant fever; from whence it is inferred, that these petechiæ, and vibices, are owing to the deficient power of absorption in the terminations of the veins, See Class I. 2. 1. 5. This sensitive inirritated fever, or typhus gravior, is distinguished from the inirritative fever, or typhus mitior, in the early stages of it, by the colour of the skin; which in the latter is paler, with less heat, owing to the less violent action of the capillaries; in this it is higher coloured, and hotter, from the greater energy of the capillary action in the production of new vessels. In the more advanced state petechiæ, and the production of contagious matter from inflamed membranes, as the aphthæ of the mouth, or ulcers of the throat, distinguishes this fever from the former. Delirium, and dilated pupils of the eyes, are more frequent in nervous fevers; and stupor with deafness more frequent attendants on malignant fevers. See Class I. 2. 5. 6. There is another criterion discernible by the touch of an experienced finger; and that is, the coat of the artery in inflammatory fevers, both those attended with strength of pulsation, and these with weak pulsation, feels harder, or more like a cord; for the coats of the arteries in these fevers are themselves inflamed, and are consequently turgid with blood, and thence are less easily compressed, though their pulsations are nevertheless weak: when the artery is large or full with an inflamed coat, it is called hard; and when small or empty with an inflamed coat, it is called sharp, by many writers. M. M. The indications of cure consist, 1. In procuring a regurgitation of any offensive material, which may be lodged in the long mouths of the lacteals or lymphatics, or in their tumid glands. 2. To excite the system into necessary action by the repeated exhibition of nutrientia, sorbentia, and incitantia; and to preserve the due evacuation of the bowels. 3. To prevent any unnecessary expenditure of sensorial power. 4. To prevent the formation of ulcers, or to promote the absorption in them, for the purpose of healing them. 1. One ounce of wine of ipecacuanha, or about ten grains of the powder, should be given as an emetic. After a few hours three or four grains of calomel should be given in a little mucilage, or conserve. Where something swallowed into the stomach is the cause of the fever, it is liable to be arrested by the lymphatic glands, as the matter of the small-pox inoculated in the arm is liable to be stopped by the axillary lymphatic gland; in this situation it may continue a day or two, or longer, and may be regurgitated during the operation of an emetic or cathartic into the stomach or bowel, as evidently happens on the exhibition of calomel, as explained in Sect. XXIX. 7. 2. For this reason an emetic and cathartic, with venesection, if indicated by the hardness and fulness of the pulse, will very frequently remove fevers, if exhibited on the first, second, or even third day. 2. Wine and opium, in small doses repeated frequently, but so that not the least degree of intoxication follows, for in that case a greater degree of debility is produced from the expenditure of sensorial power in unnecessary motions. Many weak patients have been thus stimulated to death. See Sect. XII. 7. 8. The Peruvian bark should be given also in repeated doses in such quantity only as may strengthen digestion, not impede it. For these purposes two ounces of wine, or of ale, or cyder, should be given every six hours; and two ounces of decoction of bark, with two drachms of the tincture of bark, and six drops of tincture of opium, should be given also every six hours alternately; that is, each of them four times in twenty-four hours. As much rhubarb as may induce a daily evacuation, should be given to remove the colluvies of indigested materials from the bowels; which might otherwise increase the distress of the patient by the air it gives out in putrefaction, or by producing a diarrhoea by its acrimony; the putridity of the evacuations are in consequence of the total inability of the digestive powers; and their delay in the intestines, to the inactivity of that canal in respect to its peristaltic motions. The quantities of wine or beer and opium, and bark, above mentioned, may be increased by degrees, if the patient seems refreshed by them; and if the pulse becomes slower on their exhibition; but this with caution, as I have seen irrecoverable mischief done by greater quantities both of opium, wine, and bark, in this kind of fever; in which their use is to strengthen the digestion of the weak patient, rather than to stop the paroxysms of fever; but when they are administered in intermittents, much larger quantities are necessary. The stimulus of small blisters applied in succession, one every three or four days, when the patient becomes weak, is of great service by strengthening digestion, and by preventing the coldness of the extremities, owing to the sympathy of the skin with the stomach, and of one part of the skin with another. In respect to nutriment, the patient should be supplied with wine and water, with toasted bread, and sugar or spice in it; or with sago with wine; fresh broth with turnips, cellery, parsley; fruit; new milk. Tea with cream and sugar; bread pudding, with lemon juice and sugar; chicken, fish, or whatever is grateful to the palate of the sick person, in small quantity repeated frequently; with small beer, cyder and water, or wine and water, for drink, which may be acidulated with acid of vitriol in small quantities. 3. All unnecessary motions are to be checked, or prevented. Hence horizontal posture, obscure room, silence, cool air. All the parts of the skin, which feel too hot to the hand, should be exposed to a current of cool air, or bathed with cold water, whether there are eruptions on it or not. Wash the patient twice a day with cold vinegar and water, or cold salt and water, or cold water alone, by means of a sponge. If some parts are too cold, as the extremities, while other parts are too hot, as the face or breast, cover the cold parts with flannel, and cool the hot parts by a current of cool air, or bathing them as above. 4. For the healing of ulcers, if in the mouth, solution of alum in water about 40 grains to an ounce, or of blue vitriol in water, one grain or two to an ounce may be used to touch them with three or four times a day. Of these perhaps a solution of alum is to be preferred, as it instantly takes away the stench from ulcers I suppose by combining with the volatile alcali which attends it. For this purpose a solution of alum of an ounce to a pint of water should be frequently injected by means of a syringe into the mouth. If there are ulcers on the external skin, fine powder of bark seven parts, and cerusia in fine powder one part, should be mixed, and applied dry on the sore, and kept on by lint, and a bandage. As sloughs in the mouth are frequently produced by the previous dryness of the membranes, which line it, this dryness should be prevented by frequently moistening them, which may be effected by injection with a syringe, or by a moist sponge, or lastly in the following manner. Place a glass of wine and water, or of milk and sugar, on a table by the bedside, a little above the level of the mouth of the patient; then, having previously moistened a long piece of narrow listing, or cloth, or flannel, with the same liquor, leave one end of it in the glass, and introduce the other into the mouth of the patient; which will thus be supplied with a constant oozing of the fluid through the cloth, which acts as a capillary syphon. The viscid phlegm, which adheres to the tongue, should be coagulated by some austere acid, as by lemon-juice evaporated to half its quantity, or by crab-juice; and then it may be scraped off by a knife, or rubbed off by flannel, or a sage leaf dipped in vinegar, or in salt and water. 2. _Erysipelas_, St. Anthony's fire, may be divided into three kinds, which differ in their method of cure, the irritated, the inirritated, and the sensitive erysipelas. _Erysipelas irritatum_ is attended with increase of irritation besides increase of sensation; that is, with strong, hard, and full pulse, which requires frequent venesection, like other inflammations with arterial strength. It is distinguished from the phlegmonic inflammations of the last genus by its situation on the external habit, and by the redness, heat, and tumour not being distinctly circumscribed; so that the eye or finger cannot exactly trace the extent of them. When the external skin is the seat of inflammation, and produces sensitive irritated fever, no collection of matter is formed, as when a phlegmon is situated in the cellular membrane beneath the skin; but the cuticle rises as beneath a blister-plaster, and becomes ruptured; and a yellow material oozes out, and becomes inspissated, and lies upon its surface; as is seen in this kind of erysipelas, and in the confluent small-pox; or if the new vessels are reabsorbed the cuticle peels off in scales. This difference of the termination of erysipelatous and phlegmonic inflammation seems to be owing in part to the less distensibility of the cuticle than of the cellular membrane, and in part to the ready exhalation of the thinner parts of the secreted fluids through its pores. This erysipelas is generally preceded by a fever for two or three days before the eruption, which is liable to appear in some places, as it declines in others; and seems frequently to arise from a previous scratch or injury of the skin; and is attended sometimes with inflammation of the cellular membrane beneath the skin; whence a real phlegmon and collection of matter becomes joined to the erysipelas, and either occasions or increases the irritated fever, which attends it. There is a greater sympathy between the external skin and the meninges of the brain, than between the cellular membrane and those meninges; whence erysipelas is more liable to be preceded or attended, or succeeded, by delirium than internal phlegmons. I except the mumps, or parotitis, described below; which is properly an external gland, as its excretory duct opens into the air. When pain of the head or delirium precedes the cutaneous eruption of the face, there is some reason to believe, that the primary disease is a torpor of the meninges of the brain; and that the succeeding violent action is transferred to the skin of the face by sensitive association; and that a similar sympathy occurs between some internal membranes and the skin over them, when erysipelas appears on other parts of the body. If this circumstance should be supported by further evidence, this disease should be removed into Class IV. along with the rheumatism and gout. See Class IV. 1. 2. 17. This supposed retropulsion of erysipelas on the brain from the frequent appearance of delirium, has prevented the free use of the lancet early in this disease to the destruction of many; as it has prevented the subduing of the general inflammation, and thus has in the end produced the particular one on the brain. Mr. B----, a delicate gentleman about sixty, had an erysipelas beginning near one ear, and extending by degrees over the whole head, with hard, full, and strong pulse; blood was taken from him four or five times in considerable quantity, with gentle cathartics, with calomel, diluents, and cool air, and he recovered without any signs of delirium, or inflammation of the meninges of the brain. Mr. W----, a strong corpulent man of inferior life, had erysipelas over his whole head, with strong hard pulse: he was not evacuated early in the disease through the timidity of his apothecary, and died delirious. Mrs. F---- had erysipelas on the face, without either strong or weak pulse; that is, with sensitive fever alone, without superabundance or deficiency of irritation; and recovered without any but natural evacuations. From these three cases of erysipelas on the head it appears, that the evacuations by the lancet must be used with courage, where the degree of inflammation requires it; but not where this degree of inflammation is small, nor in the erysipelas attended with inirritation, as described below. M. M. Venesection repeated according to the degree of inflammation. An emetic. Calomel three grains every other night. Cool air. Diluents, emetic tartar in small doses, as a quarter of a grain every six hours. Tea, weak broth, gruel, lemonade, neutral salts. See Sect. XII. 6. Such external applications as carry away the heat of the skin may be of service, as cold water, cold flour, snow, ether. Because these applications impede the exertions of the secerning vessels, which are now in too great action; but any applications of the stimulant kind, as solutions of lead, iron, copper, or of alum, used early in the disease, must be injurious; as they stimulate the secerning vessels, as well as the absorbent vessels, into greater action; exactly as occurs when stimulant eye-waters are used too soon in ophthalmy. See Class II. 1. 2. 2. But as the cuticle peels off in this case after the inflammation ceases, it differs from ophthalmy; and stimulant applications are not indicated at all, except where symptoms of gangrene appear. For as a new cuticle is formed under the old one, as under a blister, the serous fluid between them is a defence to the new cuticle, and should dry into a scab by exhalation rather than be reabsorbed. Hence we see how greasy or oily applications, and even how moist ones, are injurious in erysipelas; because they prevent the exhalation of the serous effusion between the old and new cuticle, and thus retard the formation of the latter. _Erysipelas inirritatum_ differs from the former in its being attended with weak pulse, and other symptoms of sensitive inirritated fever. The feet and legs are particularly liable to this erysipelas, which precedes or attends the sphacelus or mortification of those parts. A great and long coldness first affects the limb, and the erysipelas on the skin seems to occur in consequence of the previous torpor of the interior membranes. As this generally attends old age, it becomes more dangerous in proportion to the age, and also to the habitual intemperance of the patient in respect to the use of fermented or spirituous liquor. When the former kind, or irritated erysipelas, continues long, the patient becomes so weakened as to be liable to all the symptoms of this inirritated erysipelas; especially where the meninges of the brain are primarily affected. As in that case, after two or three efforts have been made to remove the returning periods of torpor of the meninges to the external skin, those meninges become inflamed themselves, and the patient sinks under the disease; in a manner similar to that in old gouty patients, where the torpor of the liver or stomach is relieved by association of the inflammation of the membranes of the feet, and then of other joints, and lastly the power of association ceasing to act, but the excess of sensation continuing, the liver or stomach remains torpid, or become themselves inflamed, and the patient is destroyed. M. M. Where there exists a beginning gangrene of the extremities, the Peruvian bark, and wine, and opium, are to be given in large quantities; so as to strengthen the patient, but not to intoxicate, or to impede his digestion of aliment, as mentioned in the first species of this genus. Class II. 1. 2. 1. But where the brain is inflamed or oppressed, which is known either by delirium, with quick pulse; or by stupor, and slow respiration with slow pulse; other means must be applied. Such as, first, a fomentation on the head with warm water, with or without aromatic herbs, or salt in it, should be continued for an hour or two at a time, and frequently repeated. A blister may also be applied on the head, and the fomentation nevertheless occasionally repeated. Internally very gentle stimulants, as camphor one grain or two in infusion of valerian. Wine and water or small beer, weak broth. An enema. Six grains of rhubarb and one of calomel. Afterwards five drops of tincture of opium, which may be repeated every six hours, if it seems of service. Might the head be bathed for a minute with cold water? or with ether? or vinegar? _Erysipelas sensitivum_ is a third species, differing only in the kind of fever which attends it, which is simply inflammatory, or sensitive, without either excess of irritation, as in the first variety; or the defect of irritation, as in the second variety: all these kinds of erysipelas are liable to return by periods in some people, who have passed the middle of life, as at periods of a lunation, or two lunations, or at the equinoxes. When these periods of erysipelas happen to women, they seem to supply the place of the receding catamenia; when to men, I have sometimes believed them to be associated with a torpor of the liver; as they generally occur in those who have drank vinous spirit excessively, though not approbriously; and that hence they supply the place of periodical piles, or gout, or gutta rosea. M. M. As the fever requires no management, the disease takes its progress safely, like a moderate paroxysm of the gout; but in this case, as in some of the former, the erysipelas does not appear to be a primary disease, and should perhaps be removed to the Class of Association. 3. _Tonsillitis._ Inflammation of the tonsils. The uncouth term Cynanche has been used for diseases so dissimilar, that I have divided them into Tonsillitis and Parotitis; and hope to be excused for adding a Greek termination to a Latin word, as one of those languages may justly be considered as a dialect of the other. By tonsillitis the inflammation of the tonsils is principally to be understood; but as all inflammations generally spread further than the part first affected; so, when the summit of the windpipe is also much inflamed, it may be termed tonsillitis trachealis, or croup. See Class I. 1. 3. 4. and II. 1. 2. 4.; and when the summit of the gullet is much inflamed along with the tonsil, it may be called tonsillitis pharyngea, as described in Dr. Cullen's Nosologia, Genus X. p. 92. The inflammation of the tonsils may be divided into three kinds, which require different methods of cure. _Tonsillitis interna._ Inflammation of the internal tonsil. When the swelling is so considerable as to produce difficulty of breathing, the size of the tonsil should be diminished by cutting it with a proper lancet, which may either give exit to the matter it contains, or may make it less by discharging a part of the blood. This kind of angina is frequently attended with irritated fever besides the sensitive one, which accompanies all inflammation, and sometimes requires venesection. An emetic should be given early in the disease, as by its inducing the retrograde action of the vessels about the fauces during the nausea it occasions, it may eliminate the very cause of the inflammation; which may have been taken up by the absorbents, and still continue in the mouths of the lymphatics or their glands. The patient should then be induced to swallow some aperient liquid, an infusion of senna, so as to induce three or four evacuations. Gargles of all kinds are rather hurtful, as the action of using them is liable to give pain to the inflamed parts; but the patients find great relief from frequently holding warm water in their mouths, and putting it out again, or by syringing warm water into the mouth, as this acts like a warm bath or fomentation to the inflamed part. Lastly, some mild stimulant, as a weak solution of salt and water, or of white vitriol and water, may be used to wash the fauces with in the decline of the disease, to expedite the absorption of the new vessels, if necessary, as recommended in ophthalmy. _Tonsillitis superficialis._ Inflammation of the surface of the tonsils. As the tonsils and parts in their vicinity are covered with a membrane, which, though exposed to currents of air, is nevertheless constantly kept moist by mucus and saliva, and is liable to diseases of its surface like other mucous membranes, as well as to suppuration of the internal substance of the gland; the inflammation of its surface is succeeded by small elevated pustules with matter in them, which soon disappears, and the parts either readily heal, or ulcers covered with sloughs are left on the surface. This disease is generally attended with only sensitive fever, and therefore is of no danger, and may be distinguished with great certainty from the dangerous inflammation or gangrene of the tonsils at the height of the small-pox, or scarlet fever, by its not being attended with other symptoms of those diseases. One emetic and a gentle cathartic is generally sufficient; and the frequent swallowing of weak broth, or gruel, both without salt in them, relieves the patient, and absolves the cure. When these tumours of the tonsils frequently return I have sometimes suspected them to originate from the absorption of putrid matter from decaying teeth. See Class I. 2. 3. 21. and II. 2. 2. 1. _Tonsillitis inirritata._ Inflammation of the tonsils with sensitive inirritated fever is a symptom only of contagious fever, whether attended with scarlet eruption, or with confluent small-pox, or otherwise. The matter of contagion is generally diffused, not dissolved in the air; and as this is breathed over the mucaginous surface of the tonsils, the contagious atoms are liable to be arrested by the tonsil; which therefore becomes the nest of the future disease, like the inflamed circle round the inoculated puncture of the arm in supposititious small-pox. This swelling is liable to suffocate the patient in small-pox, and to become gangrenous in scarlet fever, and some other contagious fevers, which have been received in this manner. The existence of inflammation of the tonsil previous to the scarlet eruption, as the arm inflames in the inoculated small-pox, and suppurates before the variolous eruption, should be a criterion of the scarlet fever being taken in this manner. M. M. All the means which strengthen the patient, as in the sensitive inirritated fever, Class II. 1. 2. 1. As it is liable to continue a whole lunation or more, great attention should be used to nourish the patient with acidulous and vinous panada, broth with vegetables boiled in it, sugar, cream, beer; all which given frequently will contribute much to moisten, clean, and heal the ulcuscles, or sloughs, of the throat; warm water and wine, or acid of lemon, should be frequently applied to the tonsils by means of a syringe, or by means of a capillary syphon, as described in Class II. 1. 3. 1. A slight solution of blue vitriol, as two grains to an ounce, or a solution of sugar of lead of about six grains to an ounce, may be of service; especially the latter, applied to the edges of the sloughs, drop by drop by means of a small glass tube, or small crow-quill with the end cut off, or by a camel's-hair pencil or sponge; to the end of either of which a drop will conveniently hang by capillary attraction; as solutions of lead evidently impede the progress of erysipelas on the exterior skin, when it is attended with feeble pulse. Yet a solution of alum injected frequently by a syringe is perhaps to be preferred, as it immediately removes the fetor of the breath, which must much injure the patient by its being perpetually received into the lungs by respiration. 4. _Parotitis._ Mumps, or branks, is a contagious inflammation of the parotis and maxillary glands, and has generally been classed under the word Cynanche or Angina, to which it bears no analogy. It divides itself into two kinds, which differ in the degree of fever which attends them, and in the method of cure. _Parotitis suppurans._ The suppurating mumps is to be distinguished by the acuteness of the pain, and the sensitive, irritated, or inflammatory fever, which attends it. M. M. Venesection. Cathartic with calomel three or four grains repeatedly. Cool air, diluents. This antiphlogistic treatment is to be continued no longer than is necessary to relieve the violence of the pain, as the disease is attended with contagion, and must run through a certain time, like other fevers with contagion. _Parotitis mutabilis._ Mutable parotitis. A sensitive fever only, or a sensitive irritated fever, generally attends this kind. And when the tumor of the parotis and maxillary glands subsides, a new swelling occurs in some distant part of the system; as happens to the hands and feet, at the commencement of the secondary fever of the small-pox, when the tumor of the face subsides. This new swelling in the parotitis mutabilis is liable to affect the testes in men, and form a painful tumor, which should be prevented from suppuration by very cautious means, if the violence of the pain threaten such a termination; as by bathing the part with coldish water for a time, venesection, a cathartic; or by a blister on the perinæum, or scrotum, or a poultice. When women are affected with this complaint, after the swelling of the parotis and maxillary glands subsides, a tumor with pain is liable to affect their breasts; which, however, I have never seen terminate in suppuration. On the retrocession of the tumor of the testes above described, and I suppose of that of the breasts in women, a delirium of the calm kind is very liable to occur; which in some cases has been the first symptom which has alarmed the friends of the patient; and it has thence been difficult to discover the cause of it without much inquiry; the previous symptoms having been so slight as not to have occasioned any complaints. In this delirium, if the pulse will bear it, venesection should be used, and three or four grains of calomel, with fomentation of the head with warm water for an hour together every three or four hours. Though this disease generally terminates favourably, considering the numbers attacked by it, when it is epidemic, yet it is dangerous at other times in every part of its progress. Sometimes the parotis or maxillary glands suppurate, producing ulcers which are difficult to cure, and frequently destroy the patient, where there was a previous scrophulous tendency. The testis in men is also liable to suppurate with great pain, long confinement, and much danger; and lastly the affection of the brain is fatal to many. Mr. W. W. had a swelled throat, which after a few days subsided. He became delirious or stupid, in which state he was dying when I saw him; and his friends ascribed his death to a coup de soleil, which he was said to have received some months before, when he was abroad. Mr. A. B. had a swelling of the throat, which after a few days subsided. When I saw him he had great stupor, with slow breathing, and partial delirium. On fomenting his head with warm water for an hour these symptoms of stupor were greatly lessened, and his oppressed breathing gradually ceased, and he recovered in one day. Mr. C. D. I found walking about the house in a calm delirium without stupor; and not without much inquiry of his friends could get the previous history of the disease; which had been attended with parotitis, and swelled testis, previous to the delirium. A few ounces of blood were taken away, a gentle cathartic was directed, and his head fomented with warm water for an hour, with a small blister on the back, and he recovered in two or three days. Mr. D. D. came down from London in the coach alone, so that no previous history could be obtained. He was walking about the house in a calm delirium, but could give no sensible answers to any thing which was proposed to him. His pulse was weak and quick. Cordials, a blister, the bark, were in vain exhibited, and he died in two or three days. Mr. F. F. came from London in the same manner in the coach. He was mildly delirious with considerable stupor, and moderate pulse, and could give no account of himself. He continued in a kind of cataleptic stupor, so that he would remain for hours in any posture he was placed, either in his chair, or in bed; and did not attempt to speak for about a fortnight; and then gradually recovered. These two last cases are not related as being certainly owing to parotitis, but as they might probably have that origin. The parotitis suppurans, or mumps with irritated fever, is at times epidemic among cats, and may be called _parotitis felina_; as I have reason to believe from the swellings under the jaws, which frequently suppurate, and are very fatal to those animals. In the village of Haywood, in Staffordshire, I remember a whole breed of Persian cats, with long white hair, was destroyed by this malady, along with almost all the common cats of the neighbourhood; and as the parotitis or mumps had not long before prevailed amongst human beings in that part of the country, I recollect being inclined to believe, that the cats received the infection from mankind; though in all other contagious diseases, except the rabies canina can be so called, no different genera of animals naturally communicate infection to each other; and I am informed, that vain efforts have been made to communicate the small-pox and measles to some quadrupeds by inoculation. A disease of the head and neck destroyed almost all the cats in Westphalia. Savage, Nosol. Class X. Art. 30. 8. 5. _Catarrhus sensitivus_ consists of an inflammation of the membrane, which lines the nostrils and fauces. It is attended with sensitive fever alone, and is cured by the steam of warm water externally, and by diluents internally, with moderate venesection and gentle cathartics. This may be termed catarrhus sensitivus, to distinguish it from the catarrhus contagiosus, and is in common language called a violent cold in the head; it differs from the catarrhus calidus, or warm catarrh, of Class I. 1. 2. 7. in the production of new vessels, or inflammation of the membrane, and the consequent more purulent appearance of the discharge. Raucedo catarrhalis, or catarrhal hoarseness, is a frequent symptom of this disease, and is occasioned by the pain or soreness which attends the thickened and inflamed membranes of the larynx; which prevents the muscles of vocallity from sufficiently contracting the aperture of it. It ceases with the inflammation, or may be relieved by the steam of warm water alone, or of water and vinegar, or of water and ether. See Paralytic Hoarseness, Class III. 2. 1. 4. 6. _Catarrhus contagiosus._ This malady attacks so many at the same time, and spreads gradually over so great an extent of country, that there can be no doubt but that it is disseminated by the atmosphere. In the year 1782 the sun was for many weeks obscured by a dry fog, and appeared red as through a common mist. The material, which thus rendered the air muddy, probably caused the epidemic catarrh, which prevailed in that year, and which began far in the north, and extended itself over all Europe. See Botanic Garden, Vol. II. note on Chunda, and Vol. I. Canto IV, line 294, note; and was supposed to have been thrown out of a volcano, which much displaced the country of Iceland. In many instances there was reason to believe, that this disease became contagious, as well as epidemic; that is, that one person might receive it from another, as well as by the general unsalutary influence of the atmosphere. This is difficult to comprehend, but may be conceived by considering the increase of contagious matter in the small-pox. In that disease one particle of contagious matter stimulates the skin of the arm in inoculation into morbid action so as to produce a thousand particles similar to itself; the same thing occurs in catarrh, a few deleterious atoms stimulate the mucous membrane of the nostrils into morbid actions, which produce a thousand other particles similar to themselves. These contagious particles diffused in the air must have consisted of animal matter, otherwise how could an animal body by being stimulated by them produce similar particles? Could they then have had a volcanic origin, or must they not rather have been blown from putrid marshes full of animal matter? But the greatest part of the solid earth has been made from animal and vegetable recrements, which may be dispersed by volcanos.--Future discoveries must answer these questions. As the sensitive fever attending these epidemic catarrhs is seldom either much irritated or inirritated, venesection is not always either clearly indicated or forbid; but as those who have died of these catarrhs have generally had inflamed livers, with consequent suppuration in them, venesection is adviseable, wherever the cough and fever are greater than common, so as to render the use of the lancet in the least dubious. And in some cases a second bleeding was necessary, and a mild cathartic or two with four grains of calomel; with mucilaginous subacid diluents; and warm steam occasionally to alleviate the cough, finished the cure. The catarrhus contagiosus is a frequent disease amongst horses and dogs; it seems first to be disseminated amongst these animals by miasmata diffused in the atmosphere, because so many of them receive it at the same time; and afterwards to be communicable from one horse or dog to another by contagion, as above described. These epidemic or contagious catarrhs more frequently occur amongst dogs and horses than amongst men; which is probably owing to the greater extension and sensibility of the mucous membrane, which covers the organ of smell, and is diffused over their wide nostrils, and their large maxillary and frontal cavities. And to this circumstance may be ascribed the greater fatality of it to these animals. In respect to horses, I suspect the fever at the beginning to be of the sensitive, irritated, or inflammatory kind, because there is so great a discharge of purulent mucus; and that therefore they will bear once bleeding early in the disease; and also one mild purgative, consisting of about half an ounce of aloe, and as much white hard soap, mixed together. They should be turned out to grass both day and night for the benefit of pure air, unless the weather be too cold (and in that case they should be kept in an open airy stable, without being tied), that they may hang down their heads to facilitate the discharge of the mucus from their nostrils. Grass should be offered them, or other fresh vegetables, as carrots and potatoes, with mashes of malt, or of oats, and with plenty of fresh warm or cold water frequently in a day. When symptoms of debility appear, which may be known by the coldness of the ears or other extremities, or when sloughs can be seen on the membrane which lines the nostrils, a drink consisting of a pint of ale with half an ounce of tincture of opium in it, given every six hours, is likely to be of great utility. In dogs I believe the catarrh is generally joined with symptoms of debility early in the disease. These animals should be permitted to go about in the open air, and should have constant access to fresh water. The use of being as much as may be in the air is evident, because all the air which they breathe passes twice over the putrid sloughs of the mortified parts of the membrane which lines the nostrils, and the maxillary and frontal cavities; that is, both during inspiration and expiration; and must therefore be loaded with contagious particles. Fresh new milk, and fresh broth, should be given them very frequently, and they should be suffered to go amongst the grass, which they sometimes eat for the purpose of an emetic; and if possible should have access to a running stream of water. As the contagious mucus of the nostrils, both of these animals and of horses, generally drops into the water they attempt to drink. Bits of raw flesh, if the dog will eat them, are preferred to cooked meat; and from five to ten drops of tincture of opium may be given with advantage, when symptoms of debility are evident, according to the size of the dog, every six hours. If sloughs can be seen in the nostrils, they should be moistened twice a day, both in horses and dogs, with a solution of sugar of lead, or of alum, by means of a sponge fixed on a bit of whale bone, or by a syringe. The lotion may be made by dissolving half an ounce of sugar of lead in a pint of water. Ancient philosophers seem to have believed, that the contagious miasmata in their warm climates affected horses and dogs previous to mankind. If those contagious particles were supposed to be diffused amongst the heavy inflammable air, or carbonated hydrogen, of putrid marshes, as these animals hold their heads down lower to the ground, they may be supposed to have received them sooner than men. And though men and quadrupeds might receive a disease from the same source of marsh-putrefaction, they might not afterwards be able to infect each other, though they might infect other animals of the same genus; as the new contagious matter generated in their own bodies might not be precisely similar to that received; as happened in the jail-fever at Oxford, where those who took the contagion and died, did not infect others. On mules and dogs the infection first began, And, last, the vengeful arrows fix'd on man. POPE'S Homer's Iliad, I. 7. _Peripneumonia superficialis._ The superficial or spurious peripneumony consists in an inflammation of the membrane, which lines the bronchia, and bears the same analogy to the true peripneumony, as the inflammations of other membranes do to that of the parenchyma, or substantial parts of the viscus, which they surround. It affects elderly people, and frequently occasions their death; and exists at the end of the true peripneumony, or along with it; when the lancet has not been used sufficiently to cure by reabsorbing the inflamed parts, or what is termed by resolution. M. M. Diluents, mucilage, antimonials, warmish air constantly changed, venesection once, perhaps twice, if the pulse will bear it. Oily volatile draughts. Balsams? Neutral salts increase the tendency to cough. Blisters in succession about the chest. Warm bath. Mild purgatives. Very weak chicken broth without salt in it. Boiled onions. One grain of calomel every night for a week. From five drops to ten of tincture of opium at six every night, when the patient becomes weak. Digitalis? See Class II. 1. 6. 7. 8. _Pertussis._ Tussis convulsiva. Chin-cough resembles peripneumonia superficialis in its consisting in an inflammation of the membrane which lines the air-vessels of the lungs; but differs in the circumstance of its being contagious; and is on that account of very long duration; as the whole of the lungs are probably not infected at the same time, but the contagious inflammation continues gradually to creep on the membrane. It may in this respect be compared to the ulcers in the pulmonary consumption; but it differs in this, that in chin-cough some branches of the bronchia heal, as others become inflamed. This complaint is not usually classed amongst febrile disorders, but a sensitive fever may generally be perceived to attend it during some part of the day, especially in weak patients. And a peripneumony very frequently supervenes, and destroys great numbers of children, except the lancet or four or six leeches be immediately and repeatedly used. When the child has permanent difficulty of breathing, which continues between the coughing fits: unless blood be taken from it, it dies in two, three, or four days of the inflammation of the lungs. During this permanent difficulty of breathing the hooping-cough abates, or quite ceases, and returns again after once or twice bleeding; which is then a good symptom, as the child now possessing the power to cough shews the difficulty of breathing to be abated. I dwell longer upon this, because many lose their lives from the difficulty there is in bleeding young children; where the apothecary is old or clumsy, or is not furnished with a very sharp and fine-pointed lancet. In this distressing situation the application of four leeches to one of the child's legs, the wounds made by which should continue to bleed an hour or two, is a succedaneum; and saves the patient, if repeated once or twice according to the difficulty of the respiration. The chin-cough seems to resemble the gonorrhoea venerea in several circumstances. They are both received by infection, are both diseases of the mucous membrane, are both generally cured in four or six weeks without medicine. If ulcers in the cellular membrane under the mucous membrane occur, they are of a phagedenic kind, and destroy the patient in both diseases, if no medicine be administered. Hence the cure should be similar in both these diseases; first general evacuations and diluents, then, after a week or two, I have believed the following pills of great advantage. The dose for a child of about three years old was one sixth part of a grain of calomel, one sixth part of a grain of opium, and two grains of rhubarb, to be taken twice a day. The opium promotes absorption from the mucous membrane, and hence contributes to heal it. The mercury prevents ulcers from being formed under the mucous membrane, or cures them, as in the lues venerea; and the rhubarb is necessary to keep the bowels open. M. M. Antimonial vomits frequently repeated. Mild cathartics. Cool air. Tincture of cantharides, or repeated blisters; afterwards opiates in small doses, and the bark. Warm bath frequently used. The steam of warm water with a little vinegar in it may be inhaled twice a day. Could the breathing of carbonic acid gas mixed with atmospheric air be of service? Copious venesection, when a difficulty of breathing continues between the fits of coughing; otherwise the cough and the expectoration cease, and the patient is destroyed. Ulcers of the lungs sometimes supervene, and the phthisis pulmonalis in a few weeks terminates in death. Where the cough continues after some weeks without much of the hooping, and a sensitive fever daily supervenes, so as to resemble hectic fever from ulcers of the lungs; change of air for a week or fortnight acts as a charm, and restores the patient beyond the hopes of the physician. Young children should lie with their heads and shoulders raised; and should be constantly watched day and night; that when the cough occurs, they may be held up easily, so as to stand upon their feet bending a little forwards; or nicely supported in that posture which they seem to put themselves into. A bow of whalebone, about the size of the bow of a key, is very useful to extract the phlegm out of the mouths of infants at the time of their coughing; as an handkerchief, if applied at the time of their quick inspirations after long holding their breath, is dangerous, and may suffocate the patient in an instant, as I believe has sometimes happened. 9. _Variola discreta._ The small-pox is well divided by Sydenham into distinct and confluent. The former consists of distinct pustules, which appear on the fourth day of the fever, are circumscribed and turgid; the fever ceasing when the eruption is complete. Head-ach, pain in the loins, vomiting frequently, and convulsive fits sometimes, precede the eruption. The distinct small-pox is attended with sensitive fever only, when very mild, as in most inoculated patients; or with sensitive irritated fever, when the disease is greater: the danger in this kind of small-pox is owing either to the tumor and soreness of the throat about the height, or eighth day of the eruption; or to the violence of the secondary fever. For, first, as the natural disease is generally taken by particles of the dust of the contagious matter dried and floating in the air, these are liable to be arrested by the mucus about the throat and tonsils in their passage to the lungs, or to the stomach, when they are previously mixed with saliva in the mouth. Hence the throat inflames like the arm in inoculated patients; and this increasing, as the disease advances, destroys the patient about the height. Secondly, all those upon the face and head come out about the same time, namely, about one day before those on the hands, and two before those in the trunk; and thence, when the head is very full, a danger arises from the secondary fever, which is a purulent, not a variolous fever; for as the matter from all these of the face and head is reabsorbed at the same time, the patient is destroyed by the violence of this purulent fever; which in the distinct small-pox can only be abated by venesection and cathartics; but in the confluent small-pox requires cordials and opiates, as it is attended with arterial debility. See Sect. XXXV. 1. and XXXIII. 2. 10. When the pustules on the face recede, the face swells; and when those of the hands recede, the hands swell; and the same of the feet in succession. These swellings seem to be owing to the absorption of variolous matter, which by its stimulus excites the cutaneous vessels to secrete more lymph, or serum, or mucus, exactly as happens by the stimulus of a blister. Now, as a blister sometimes produces strangury many hours after it has risen; it is plain, that a part of the cantharides is absorbed, and carried to the neck of the bladder; whether it enters the circulation, or is carried thither by retrograde movements of the urinary branch of lymphatics; and by parity of reasoning the variolous matter is absorbed, and swells the face and hands by its stimulus. _Variola confluens._ The confluent small-pox consists of numerous pustules, which appear on the third day of the fever, flow together, are irregularly circumscribed, flaccid, and little elevated; the fever continuing after the eruption is complete; convulsions do not precede this kind of small-pox, and are so far to be esteemed a favourable symptom. The confluent small-pox is attended with sensitive inirritated fever, or inflammation with arterial debility; whence the danger of this disease is owing to the general tendency to gangrene, with petechiæ, or purple spots, and hæmorrhages; besides the two sources of danger from the tumor of the throat about the height, or eleventh day of the eruption, and the purulent fever after that time; which are generally much more to be dreaded in this than in the distinct small-pox described above. M. M. The method of treatment must vary with the degree and kind of fever. Venesection may be used in the distinct small-pox early in the disease, according to the strength or hardness of the pulse; and perhaps on the first day of the confluent small-pox, and even of the plague, before the sensorial power is exhausted by the violence of the arterial action? Cold air, and even washing or bathing in cold water, is a powerful means in perhaps all eruptive diseases attended with fever; as the quantity of eruption depends on the quantity of the fever, and the activity of the cutaneous vessels; which may be judged of by the heat produced on the skin; and which latter is immediately abated by exposure to external cold. Mercurial purges, as three grains of calomel repeated every day during the eruptive fever, so as to induce three or four stools, contribute to abate inflammation; and is believed by some to have a specific effect on the variolous, as it is supposed to have on the venereal contagion. It has been said, that opening the pock and taking out the matter has not abated the secondary fever; but as I had conceived, that the pits, or marks left after the small-pox, were owing to the acrimony of the matter beneath the hard scabs, which not being able to exhale eroded the skin, and produced ulcers, I directed the faces of two patients in the confluent small-pox to be covered with cerate early in the disease, which was daily renewed; and I was induced to think, that they had much less of the secondary fever, and were so little marked, that one of them, who was a young lady, almost entirely preserved her beauty. Perhaps mercurial plasters, or cerates, made without turpentine in them, might have been more efficacious, in preventing the marks, and especially if applied early in the disease, even on the first day of the eruption, and renewed daily. For it appears from the experiments of Van Woensel, that calomel or sublimate corrosive, triturated with variolous matter, incapacitates it from giving the disease by inoculation. Calomel or sublimate given as an alterative for ten days before inoculation, and till the eruptive fever commences, is said with certainty to render the disease mild by the same author. Exper. on Mercury by Van Woensel, translated by Dr. Fowle, Salisbury. _Variola inoculata._ The world is much indebted to the great discoverer of the good effects of inoculation, whose name is unknown; and our own country to Lady Wortley Montague for its introduction into this part of Europe. By inserting the variolous contagion into the arm, it is not received by the tonsils, as generally happens, I suppose, in the natural small-pox; whence there is no dangerous swelling of the throat, and as the pustules are generally few and distinct, there is seldom any secondary fever; whence those two sources of danger are precluded; hence when the throat in inoculated small-pox is much inflamed and swelled, there is reason to believe, that the disease had been previously taken by the tonsils in the natural way.--Which also, I suppose, has generally happened, where the confluent kind of small-pox has occurred on inoculation. I have known two instances, and have heard of others, where the natural small-pox began fourteen days after the contagion had been received; one of these instances was of a countryman, who went to a market town many miles from his home, where he saw a person in the small-pox, and on returning the fever commenced that day fortnight: the other was of a child, whom the ignorant mother carried to another child ill of the small-pox, on purpose to communicate the disease to it; and the variolous fever began on the fourteenth day from that time. So that in both these cases fever commenced in half a lunation after the contagion was received. In the inoculated small-pox the fever generally commences on the seventh day, or after a quarter of a lunation; and on this circumstance probably depends the greater mildness of the latter. The reason of which is difficult to comprehend; but supposing the facts to be generally as above related, the slower progress of the contagion indicates a greater inirritability of the system, and in consequence a tendency to malignant rather than to inflammatory fever. This difference of the time between the reception of the infection and the fever in the natural and artificial small-pox may nevertheless depend on its being inserted into a different series of vessels; or to some unknown effect of lunar periods. It is a subject of great curiosity, and deserves further investigation. When the inoculated small-pox is given under all the most favourable circumstances I believe less than one in a thousand miscarry, which may be ascribed to some unavoidable accident, such as the patient having previously received the infection, or being about to be ill of some other disease. Those which have lately miscarried under inoculation, as far as has come to my knowledge, have been chiefly children at the breast; for in these the habit of living in the air has been confirmed by so short a time, that it is much easier destroyed, than when these habits of life have been established by more frequent repetition. See Sect. XVII. 3. Thus it appears from the bills of mortality kept in the great cities of London, Paris, and Vienna, that out of every thousand children above three hundred and fifty die under two years old. (Kirkpatrick on Inoculation.) Whence a strong reason against our hazarding inoculation before that age is passed, especially in crowded towns; except where the vicinity of the natural contagion renders it necessary, or the convenience of inoculating a whole family at a time; as it then becomes better to venture the less favourable circumstances of the age of the patient, or the chance of the pain from toothing, than to risk the infection in the natural way. The most favourable method consists in, first, for a week before inoculation, restraining the patients from all kinds of fermented or spirituous liquor, and from animal food; and by giving them from one grain to three or four of calomel every other day for three times. But if the patients be in any the least danger of taking the natural infection, the inoculation had better be immediately performed, and this abstinence then began; and two or three gentle purges with calomel should be given, one immediately, and on alternate days. These cathartics should not induce more than two or three stools. I have seen two instances of a confluent small-pox in inoculation following a violent purging induced by too large a dose of calomel. Secondly, the matter used for inoculation should be in a small quantity, and warm, and fluid. Hence it is best when it can be recently taken from a patient in the disease; or otherwise it may be diluted with part of a drop of warm water, since its fluidity is likely to occasion its immediate absorption; and the wound should be made as small and superficial as possible, as otherwise ulcers have been supposed sometimes to ensue with subaxillary abscesses. Add to this, that the making two punctures either on the same, or one on each arm, secures the success of the operation in respect to communicating the infection. Thirdly, at the time of the fever or eruption the application of cool air to those parts of the skin, which are too warm, or appear red, or are covered with what is termed a rash, should be used freely, as well as during the whole disease. And at the same time, if the feet or hands are colder than natural, these should be covered with flannel. See Class IV. 2. 2. 10. 10. _Rubeola irritata, morbilli._ The measles commence with sneezing, red eyes, dry hoarse cough, and is attended with sensitive irritated fever. On the fourth day, or a little later, small thick eruptions appear, scarcely eminent above the skin, and, after three days, changing into very small branny scales. As the contagious material of the small-pox may be supposed to be diffused in the air like a fine dry powder, and mixing with the saliva in the mouth to infect the tonsils in its passage to the stomach; so the contagious material of the measles may be supposed to be more completely dissolved in the air, and thus to impart its poison to the membrane of the nostrils, which covers the sense of smell; whence a catarrh with sneezing ushers in the fever; the termination of the nasal duct of the lacrymal sac is subject to the same stimulus and inflammation, and affects by sympathy the lacrymal glands, occasioning a great flow of tears. See Sect. XVI. 8. And the redness of the eye and eyelids is produced in consequence of the tears being in so great quantity, that the saline part of them is not entirely reabsorbed. See Sect. XXIV. 2. 8. The contagion of the measles, if it be taken a sufficient time before inoculation, so that the eruption may commence before the variolous fever comes on, stops the progress of the small-pox in the inoculated wound, and delays it till the measle-fever has finished its career. See Sect. XXXIII. 2. 9. The measles are usually attended with inflammatory fever with strong pulse, and bear the lancet in every stage of the disease. In the early periods of it, venesection renders the fever and cough less; and, if any symptoms of peripneumony occur, is repeatedly necessary; and at the decline of the disease, if a cough be left after the eruption has ceased, and the subsequent branny scales are falling off, venesection should be immediately used; which prevents the danger of consumption. At this time also change of air is of material consequence, and often removes the cough like a charm, as mentioned in a similar situation at the end of the chin-cough. _Rubeola inirritata._ Measles with inirritated fever, or with weak pulse, has been spoken of by some writers. See London Med. Observ. Vol. IV. Art. XI. It has also been said to have been attended with sore throat. Edinb. Essays, Vol. V. Art. II. Could the scarlet fever have been mistaken for the measles? or might one of them have succeeded the other, as in the measles and small-pox mentioned in Sect. XXXIII. 2. 9.? From what has been said, it is probable that inoculation might disarm the measles as much as the small-pox, by preventing the catarrh, and frequent pulmonary inflammation, which attends this disease; both of which are probably the consequence of the immediate application of the contagious miasmata to these membranes. Some attempts have been made, but a difficulty seems to arise in giving the disease; the blood, I conjecture, would not infect, nor the tears; perhaps the mucous discharge from the nostrils might succeed; or a drop of warm water put on the eruptions, and scraped off again with the edge of a lancet; or if the branny scales were collected, and moistened with a little warm water? Further experiments on this subject would be worthy the public attention. 11. _Scarlatina mitis._ The scarlet fever exists with all degrees of virulence, from a flea-bite to the plague. The infectious material of this disease, like that of the small-pox, I suppose to be diffused, not dissolved, in the air; on which account I suspect, that it requires a much nearer approach to the sick, for a well person to receive the infection, than in the measles; the contagion of which I believe to be more volatile, or diffusible in the atmosphere. But as the contagious miasmata of small-pox and scarlet fever are supposed to be more fixed, they may remain for a longer time in clothes or furniture; as a thread dipped in variolous matter has given the disease by inoculation after having been exposed many days to the air, and after having been kept many months in a phial. This also accounts for the slow or sporadic progress of the scarlet fever, as it infects others at but a very small distance from the sick; and does not produce a quantity of pus-like matter, like the small-pox, which can adhere to the clothes of the attendants, and when dried is liable to be shook off in the form of powder, and thus propagate the infection. This contagious powder of the small-pox, and of the scarlet fever, becomes mixed with saliva in the mouth, and is thus carried to the tonsils, the mucus of which arrests some particles of this deleterious material; while other parts of it are carried into the stomach, and are probably decomposed by the power of digestion; as seems to happen to the venom of the viper, when taken into the stomach. Our perception of bad tastes in our mouths, at the same time that we perceive disagreeable odours to our nostrils, when we inhale very bad air, occasions us to spit out our saliva; and thus, in some instances, to preserve ourselves from infection. This has been supposed to originate from the sympathy between the organs of taste and smell; but any one who goes into a sick room close shut up, or into a crowded assembly-room, or tea-room, which is not sufficiently ventilated, may easily mix the bad air with the saliva on his tongue so as to taste it; as I have myself frequently attended to. Hence it appears that these heavy infectious matters are more liable to mix with the saliva, and inflame the tonsils, and that either before or at the commencement of the fever; and this is what generally happens in the scarlet fever, always I suppose in the malignant kind, and very frequently in the mild kind. But as this infection may be taken by other means, as by the skin, it also happens in the most mild kind, that there is no inflammation of the tonsils at all; in the same manner as there is generally no inflammation of the tonsils in the inoculated small-pox. In the mild scarlatina on the fourth day of the fever the face swells a little, at the same time a florid redness appears on various parts of the skin, in large blotches, at length coalescing, and after three days changing into branny scales. M. M. Cool air. Fruit. Lemonade. Milk and water. _Scarlatina maligna._ The malignant scarlet fever begins with inflamed tonsils; which are succeeded by dark drab coloured sloughs three or five lines in diameter, flat, or beneath the surrounding surface; and which conceal beneath them spreading gangrenous ulcers. The swellings of the tonsils are sensible to the eye and touch externally, and have an elastic rather than an oedematous feel, like parts in the vicinity of gangrenes. The pulse is very quick and weak, with delirium, and the patient generally dies in a few days; or if he recovers, it is by slow degrees, and attended with anasarca. M. M. A vomit once. Wine. Beer. Cyder. Opium. Bark; in small repeated doses. Small successive blisters, if the extremities are cooler than natural. Cool air on the hot parts of the skin, the cool extremities being at the same time covered. Iced lemonade. Broth. Custards. Milk. Jellies. Bread pudding. Chicken. Touch the ulcers with a dry sponge to absorb the contagious matter, and then with a sponge filled with vinegar, with or without sugar of lead dissolved in it, about six grains to an ounce; or with a very little blue vitriol dissolved in it, as a grain to an ounce; but nothing so instantaneously corrects the putrid smell of ulcers as a solution of alum; about half an ounce to a pint of water, which should be a little warmish, and injected into the fauces gently by means of a syringe. These should be repeated frequently in a day, if it can be done easily, and without fatigue to the child. A little powder of bark taken frequently into the mouth, as a grain or two, that it may mix with the saliva, and thus frequently stimulate the dying tonsils. Could a warm bath made of decoction of bark, or a cold fomentation with it, be of service? Could oxygene gas mixed with common air stimulate the languid system? Small electric shocks through the tonsils every hour? ether frequently applied externally to the swelled tonsils? As this disease is attended with the greatest degree of debility, and as stimulant medicines, if given in quantity, so as to produce more than natural warmth, contribute to expend the already too much exhausted sensorial power; it appears, that there is nothing so necessary to be nicely attended to, as to prevent any unnecessary motions of the system; this is best accomplished by the application of cold to those parts of the skin, which are in the least too hot. And secondly, that the exhibition of the bark in such quantity, as not to oppress the stomach and injure digestion, is next to be attended to, as not being liable to increase the actions of the system beyond their natural quantity; and that opium and wine should be given with the greatest caution, in very small repeated quantity, and so managed as to prevent, if possible, the cold fits of fever; which probably occur twice in 25 hours, obeying the lunations like the tides, as mentioned in Sect. XXXII. 6. that is, I suppose, the cold periods, and consequent exacerbations of fever, in this malignant scarlatina, occur twice in a lunar day; which is about ten minutes less than 25 hours; so that if the commencement of one cold fit be marked, the commencement of the next may be expected, if not disturbed by the exhibition of wine or opium, or the application of blisters, to occur in about twelve hours and a half from the commencement of the former; or if not prevented by large doses of the bark. No one could do an act more beneficial to society, or glorious to himself, than by teaching mankind how to inoculate this fatal disease; and thus to deprive it of its malignity. Matter might be taken from the ulcers in the throat, which would probably convey the contagion. Or warm water might be put on the eruption, and scraped off again by the edge of a lancet. These experiments could be attended with no danger, and should be tried for the public benefit, and the honour of medical science. 12. _Miliaria._ Miliary fever. An eruption produced by the warmth, and more particularly by the stimulus of the points of the wool in flannel or blankets applied to the skin, has been frequently observed; which, by cool dress, and bed-clothes without flannel, has soon ceased. See Class I. 1. 2. 3. This, which maybe called _miliaria sudatoria_, has been confounded with other miliary fevers, and has made the existence of the latter doubted. Two kinds of eruptions I have seen formerly attended with fever, but did not sufficiently mark their progress, which I conceived to be miliary eruptions, one with arterial strength, or with sensitive irritated fever, and the other with arterial debility, or with sensitive inirritated fever. In the former of these, or _miliaria irritata_, the eruptions were distinct and larger than the small-pox, and the fever was not subdued without two or three venesections, and repeated cathartics with calomel. The latter, or _miliaria inirritata_, was attended with great arterial debility; and during the course of the fever pellucid points appeared within the skin, particularly on the soft parts of the fingers. And, in one patient, whom I esteemed near her end, I well recollect to have observed round pellucid globules, like what are often seen on vines in hot-houses, no larger than the smallest pins' heads, adhere to her neck and bosom; which were hard to the touch, but were easily rubbed off. These diseases, if they are allied, do not differ more than the kinds of small-pox; but require many further observations. The eruption so often seen on children in the cradle, and called by the nurses red-gum, and which is attended with some degree of fever, I suspect to be produced by too great warmth, and the contact of flannel next their tender skins, like the miliaria sudatoria; and like that requires cool air, cool clothes, and linen next their skin. 13. _Pestis._ The plague, like other diseases of this class, seems to be sometimes mild, and sometimes malignant; according to the testimony of different writers. It is said to be attended with inflammation, with the greatest arterial debility, and to be very contagious, attended at an uncertain time of the fever with buboes and carbuncles. Some authors affirm, that the contagion of the plague may be repeatedly received, so as to produce the disease; but as this is contrary to the general analogy of all contagious diseases, which are attended with fever, and which cure themselves spontaneously; there is reason to suspect, that where it has been supposed to have been repeatedly received, that some other fever with arterial debility has been mistaken for it, as has probably universally been the case, when the small-pox has been said to have been twice experienced. M. M. Venesection has been recommended by some writers on the first day, where the inflammation was supposed to be attended with sufficient arterial strength, which might perhaps sometimes happen, as the bubo seems to be a suppuration; but the carbuncle, or anthrax, is a gangrene of the part, and shews the greatest debility of circulation. Whence all the means before enumerated in this genus of diseases to support the powers of life are to be administered. Currents of cold air, cold water, ice, externally on the hot parts of the skin. The methods of preventing the spreading of this disease have been much canvassed, and seem to consist in preventing all congregations of the people, as in churches, or play-houses; and to remove the sick into tents on some airy common by the side of a river, and supply them with fresh food, both animal and vegetable, with beer and wine in proper quantities, and to encourage those who can, daily to wash both their clothes and themselves. The _pestis vaccina_, or disease amongst the cows, which afflicted this island about half a century ago, seems to have been a contagious fever with great arterial debility; as in some of them in the latter stage of the disease, an emphysema could often be felt in some parts, which evinced a considerable progress of gangrene beneath the skin. In the sensitive inirritated fevers of these animals, I suppose about sixty grains of opium, with two ounces of extract of oak-bark, every six hours, would supply them with an efficacious medicine; to which might be added thirty grains of vitriol of iron, if any tendency to bloody urine should appear, to which this animal is liable. The method of preventing the infection from spreading, if it should ever again gain access to this island, would be immediately to obtain an order from government to prevent any cattle from being removed, which were found within five miles of the place supposed to be infected, for a few days; till the certainty of the existence of the pestilence could be ascertained, by a committee of medical people. As soon as this was ascertained, all the cattle within five miles of the place should be immediately slaughtered, and consumed within the circumscribed district; and their hides put into lime-water before proper inspectors. 14. _Pemphigus_ is a contagious disease attended with bladdery eruptions appearing on the second or third day, as large as filberts, which, remain many days, and then effuse a thin ichor. It seems to be either of a mild kind with sensitive fever only, of which I have seen two instances, or with irritated, or with inirritated fever, as appears from the observations of M. Salabert. See Medical Comment, by Dr. Duncan, Decad. II. Vol. VI. 15. _Varicella._ Chicken-pox is accompanied with sensitive fever, pustules break out after a mild fever like the small-pox, seldom suppurate, and generally terminate in scales without scars. I once saw a lady, who miscarryed during this disease, though all her children had it as slightly as usual. It sometimes leaves scars or marks on the skin. This disease has been mistaken for the small-pox, and inoculated for it; and then the small-pox has been supposed to happen twice to the same person. See Trans. of the College London. It is probable that the pemphigus and urticaria, as well as this disease, have formerly been diseases of more danger; which the habit of innumerable generations may have rendered mild, and will in process of time annihilate. In the same manner as the small-pox, venereal disease, and rickets, seem to become milder or less in quantity every half century. While at the same time it is not improbable, that other new diseases may arise, and for a season thin mankind! 16. _Urticaria._ Nettle-rash begins with mild sensitive fever, which is sometimes scarcely perceptible. Hence this eruption has been thought of two sorts, one with and the other without fever. On the second day red spots, like parts stung with nettles, are seen; which almost vanish during the day, and recur in the evening with the fever, succeeded in a few days by very minute scales. See Trans. of the College, London. 17. _Aphtha._ Thrush. It has been doubted, whether aphtha or thrush, which consists of ulcers in the mouth, should be enumerated amongst febrile diseases; and whether these ulcers are always symptomatic, or the consequence rather than the cause of the fevers which attend them. The tongue becomes rather swelled; its colour and that of the fauces purplish; sloughs or ulcers appear first on the throat and edges of the tongue, and at length over the whole mouth. These sloughs are whitish, sometimes distinct, often coalescing, and remain an uncertain time. Cullen. I shall concisely mention four cases of aphtha, but do not pretend to determine whether they were all of them symptomatic or original diseases. _Aphtha sensitiva._ A lady during pregnancy was frequently seized with ulcers on her tongue and cheeks, or other parts of the mouth, without much apparent fever; which continued two or three weeks, and returned almost every month. The thrush in the mouths of young children seems to be a similar disease. These ulcers resemble those produced in the sea-scurvy, and have probably for their cause an increased action of the secerning system from increased sensation, with a decreased action of the absorbent system from decreased irritation. See Class I. 2. 1. 15. M. M. Solutions of alum, of blue vitriol. Powder of bark taken frequently into the mouth in very small quantity. See Class II. 1. 3. 1. _Aphtha irritata._ Inflammatory aphtha. A case of this kind is related under the title of suppurative rheumatism. Class IV. 1. 2. 16. _Aphtha inirritata._ Sloughs or ulcers of the mouth, attended with sensitive fever with great arterial debility. They seem to spread downwards from the throat into the stomach, and probably through the whole intestinal canal, beginning their course with cardialgia, and terminating it with tenesmus; and might perhaps be called an erysipelas of this mucous membrane. M. M. Cool air. A small blister on the back. Bark. Wine. Opium in small repeated quantities. Soap neutralizes the gastric acid without effervescence, and thus relieves the pain of cardialgia, where the stomach is affected. Milk also destroys a part of this acid. Infusion of sage leaves two ounces, almond soap from five grains to ten, with sugar and cream, is generally both agreeable and useful to these patients. See I. 2. 4. 5. Where the stomach may be supposed to be excoriated by poisons containing acid, as sublimate of mercury or arsenic; or if it be otherwise inflamed, or very sensible to the stimulus of the gastric acid; or where it abounds with acid of any kind, as in cardialgia; the exhibition of soap is perhaps a preferable manner of giving alcali than any other, as it decomposes in the stomach without effervescence; while the caustic alcali is too acrid to be administered in such cases, and the mild alcali produces carbonic gas. If a drop of acid of vitriol be put on cap paper, it will be long before it destroys the paper; but if a drop of mild alcali be added, a sudden effervescence arises, and the paper is instantly destroyed by the escape of the fixed air; in the same manner as lumps of solid lime are broken into powder by the escape of the steam produced from the water, which is poured on them. This shews why a succession of acid and of alcaline caustics sooner destroys a part, than either of them applied separately. 18. _Dysenteria._ Bloody-flux is attended with sensitive fever generally with arterial debility; with frequent mucous or bloody stools; which contain contagious matter produced by the membranes of the intestines; the alimentary excrement being nevertheless retained; with griping pains and tenesmus. M. M. Emetics. Antimonials. Peruvian bark. Opium and calomel of each a grain every night. Bolus armeniæ. Earth of alum. Chalk. Calcined hartshorn. Mucilage. Bee's wax mixt with yolk of egg. Cerated glass of antimony. Warm bath. Flannel clothing next to the skin. Large clysters with opium. With ipecacuanha, with smoke of tobacco? Two dysenteric patients in the same ward of the infirmary at Edinburgh quarrelled, and whipped each other with horsewhips a long time, and were both much better after it, owing perhaps to the exertion of so much of the sensorial power of volition; which, like real insanity, added excitement to the whole system. The prevention of this contagion must consist principally in ventilation and cleanliness; hence the patients should be removed into cottages distant from each other, or into tents; and their fæces buried as soon as may be; or conveyed into a running stream; and themselves should be washed with cold or warm water after every evacuation. For the contagious matter consists in the mucous or purulent discharge from the membrane which lines the intestines; and not from the febrile perspiration, or breath of the patients. For the fever is only the consequence and not the cause of contagion; as appears from Genus the Fifth of this Order, where contagion exists without fever. 19. _Gastritis superficialis._ Superficial inflammation of the stomach. An erysipelatous inflammation of the stomach is mentioned by Dr. Cullen from his own observations; which is distinguished from the inflammatory gastritis by less pain, and fever, and by an erysipelatous redness about the fauces. Does this disease belong to aphtha? 20. _Enteritis superficialis._ Superficial inflammation of the bowels is also mentioned by Dr. Cullen from his own observation under the name of enteritis erythematica; and is said to be attended with less pain and fever, without vomiting, and with diarrhoea. May not this disease be referred to aphtha, or to dysentery? * * * * * ORDO I. _Increased Sensation._ GENUS IV. _With the Production of new Vessels by internal Membranes or Glands, without Fever._ Where inflammation is produced in a small part, which has not great natural sensibility, the additional sensation does not produce an increased action of the arterial system; that is, the associated motions which are employed in the circulation of the blood, those for instance of the heart, arteries, glands, capillaries, and their correspondent veins, are not thrown into increased action by so small an addition of the sensorial power of sensation. But when parts, which naturally possess more sensibility, become inflamed, the quantity of the sensorial power of sensation becomes so much increased, as to affect the associated motions belonging to the circulation, occasioning them to proceed with greater frequency; that is, a fever is induced. This is well exemplified in the internal and superficial paronychia, one of which is attended with great pain and fever, and the other with little pain and no fever. See Class II. 1. 2. 19. and II. 1. 4. 5. From hence it appears, that the sensitive fever is an accidental consequence of the topical phlegmon, or inflammation, and not a cause of it; that it is often injurious, but never salutary; and should therefore always be extinguished, as soon as may be, either by the lancet and cathartics, and diluents, and cold air, when it is of the irritated kind; or by the bark, opium, cool air, and nutrientia, when it is of the inirritated kind. SPECIES. 1. _Ophthalmia superficialis._ As the membranes, which cover the eye, are excluded from the air about one third part of the twenty-four hours; and are moistened by perpetual nictitation during the other sixteen; they may be considered as internal membranes; and from the analogy of their inflammation to that of other internal membranes, it is arranged under this genus; whilst the tonsillitis is esteemed an inflammation of an external membrane, because currents of air are perpetually passing both day and night over the fauces. The superficial ophthalmy has generally been esteemed a symptom of scrophula, when it recurs frequently in young persons; but is probably only a concomitant of that disease, as a symptom of general debility; ramifications of new red vessels, and of enlarged old ones, are spread over the white part of the eye; and it is attended with less heat, less pain, and less intolerance of light than the ophthalmia interna, described in Class II. 1. 2. 2. It occurs in those of feeble circulation, especially children of a scrophulous tendency, and seems to arise from a previous torpor of the vessels of the tunica albuginea from their being exposed to cold air; and from this torpor being more liable to occur in habits, which are naturally inirritable; and therefore more readily fall into quiescence by a smaller deduction of the stimulus of heat, than would affect stronger or more irritable habits; the consequence of this torpor is increased action, which produces pain in the eye, and that induces inflammation by the acquisition of the additional sensorial power of sensation. _Ophthalmia lymphatica_ is a kind of anasarca of the tunica adnata; in this the vessels over the sclerotica, or white part of the eye, rise considerably above the cornea, which they surround, are less red than in the ophthalmia superficialis, and appear to be swelled by an accumulation of lymph rather than of blood; it is probably owing to the temporary obstruction of a branch of the lymphatic system. M. M. If the pain be great, venesection by leeches on the temple, or cutting the temporal artery, and one purge with three or four grains of calomel should be premised. Then the Peruvian bark twice a day. Opium from a quarter to half a grain twice a day for some weeks. Bathe the eye frequently with cold water alone, or with cold water, to a pint of which is added half an ounce of salt. White vitriol six grains dissolved in one ounce of water; a drop or two to be put between the eyelids twice a day. Take very small electric sparks from the eyes every day for a fortnight. Bathe the whole head with salt and water made warm every night for some months. Send such children to a school near the sea for the convenience of sea-bathing for many months annually; such schools are to be found in or near Liverpool. When a child is afflicted with an inflamed eye of this kind, he should always sit with his back to the window or candle; but it is generally not necessary to cover it, or if the uneasy sensation of light makes this proper, the cover should stand off from the eye, so as not much to exclude the cool air from it. As covering an eye unnecessarily is liable to make that eye weaker than the other, from its not being sufficiently used, and thence to produce a squinting for ever afterwards. Nevertheless, when the pain is great, a poultice must be applied to keep the eyes moist, or a piece of oiled silk bound lightly over them. Or thus, boil an egg till it is hard, cut it longitudinally into two hemispheres, take out the yolk, sew the backs of the two hollow hemispheres of the white to a ribbon, and bind them over the eyes every night on going to bed; which, if nicely fitted on, will keep the eyes moist without any disagreeable pressure. See Class I. 1. 3. 14. _Ophthalmia equina._ An inflammation of this kind is liable to affect the eyes of horses; one cause of which is owing to a silly custom of cutting the hair out of horses' ears; by which they are not only liable to take cold at the ear, but grass seeds are liable to fall into their ears from the high racks in stables; and in both cases the eye becomes inflamed by sympathy. I once directed the temporal artery of a horse to be opened, who had frequent returns of an inflamed eye; and I believed it was of essential service to him; it is probable that the artery was afterwards contracted in the wounded part, and that thence less blood was derived to the eye: the hæmorrhage was stopped by two persons alternately keeping their fingers on the orifice, and afterwards by a long bandage of broad tape. 2. _Pterigion._ Eye-wing. A spot of inflammation sometimes begins on the inside of the lower eyelid, or on the tunica albuginea, and spreads an intertexture of red vessels from it, as from a center, which extend on the white part of the eye, and have the appearance of the wing of a fly, from whence its name. M. M. Cut the ramifications of vessels again and again with the point of a lancet close to the center of inflammation. 3. _Tarsitis palpebrarum._ Inflammation of the edges of the eyelids. This is a disease of the glands, which produce the hairs of the eye-lashes, and is frequently the cause of their falling off. After this inflammation a hard scar-like ridge is left on the edge of the eyelid, which scratches and inflames the eyeball, and becomes a very troublesome disease. The Turkish ladies are said to colour the edge of the eyelash with crude antimony in very fine powder, which not only gives lustre to the eye, as a diamond set on a black soil, but may prevent extraneous light from being reflected from these edges into the eye, and thus serve the purpose of the black feathers about the eyes of swans, described in Sect. XXXIX. 5. 1. and may also prevent the edges of the eyelids from being inflamed by the frequent stimulus of tears on them. Black lead in fine powder might be better for all these purposes than antimony, and might be put on with a camel's hair brush. M. M. Mercurial ointment smeared at night on the edges of the eyelids. Burnt alum sixty grains, hog's grease half an ounce, well rubbed into an ointment to be smeared on them in the night. Cold water frequently in the day. See Class II. 1. 1. 8. 4. _Hordeolum._ Stye. This inflammation begins either on or near the edges of the eyelids, or in the loose skin of them, and is sometimes very slow either in coming to suppuration or in dispersing. The skin beneath the lower eyelid is the most frequent seat of this tumor, which sometimes never suppurates at all, but becomes an incysted tumor: for as this skin is very loose for the purpose of admitting great motion to the eyelid, the absorbent power of the veins seems particularly weak in this part; whence when any person is weakened by fatigue or otherwise, a darker shade of colour is seen beneath the eyes; which is owing to a less energetic action of the absorbent terminations of the veins, whence the currents of dark or venous blood are delayed in them. This dark shade beneath the eyes, when it is permanent, is a symptom of habitual debility, or inirritability of the circulating system. See Class I. 2. 2. 2. M. M. Smear the tumors with mercurial ointment, moisten them frequently with ether. To promote their suppuration they may be wounded with a lancet, or slit down the middle, or they may be cut out. A caustic leaves a large scar. 5. _Paronychia superficialis._ Whitlow. An inflammation about the roots of the nail beneath the skin, which suppurates without fever, and sometimes destroys the nail; which is however gradually reproduced. This kind of abscess, though not itself dangerous, has given opportunity for the inoculation of venereal matter in the hands of accoucheurs, and of putrid matter from the dissection of diseased bodies; and has thus been the cause of disease and death. When putrid matter has been thus absorbed from a dead body, a livid line from the finger to the swelled gland in the axilla is said to be visible; which shews the inflammation of the absorbent vessel along its whole course to the lymphatic gland; and death has generally been the consequence. M. M. In the common paronychia a poultice is generally sufficient. In the absorption of putrid matter rub the whole hand and arm with mercurial ointment three or four times a day, or perpetually. Could the swelled axillary gland be exsected? In the absorption of venereal matter the usual methods of cure in syphilis must be administered, as in Class II. 1. 5. 2. 6. _Gutta rosea._ The rosy drop on the face is of three kinds. First, the _gutta rosea hepatica_, or the red pimples on the faces of drunkards, which are probably a kind of crisis, or vicarious inflammation, which succeeds, or prevents, a torpor of the membranes of the liver. This and the succeeding species properly belong to Class IV. 1. 2. 14. Secondly, the pimpled face in consequence of drinking cold water, or eating cold turnips, or other insipid food, when much heated with exercise; which probably arises from the sympathy between the skin of the face and the stomach; and may be called the _gutta rosea stomatica_. Which is distinguished from the former by the habits of the patient in respect to drinking; by the colour of the eruptions being less deep; and by the patient continuing generally to be troubled with some degree of apepsia. See Class I. 3. 1. 3. I knew a lady, who had long been afflicted with pain about the region of the stomach; and, on drinking half a pint of vinegar, as a medicine, she had a breaking out commenced on her face; which remained, and she became free from the pain about the stomach. Was this a stomachic, or an hepatic disease? Thirdly, there is a red face, which consists of smaller pimples than those above mentioned; and which is less liable to suppurate; and which seems to be hereditary, or at least has no apparent cause like those above mentioned; which may be termed _gutta rosea hereditaria_, or puncta rosea. Mrs. S. had a pimpled face, which I believe arose from potation of ale. She applied alum in a poultice to it, and had soon a paralytic stroke, which disabled her on one side, and terminated in her death. Mrs. L. had a red pimpled face, which seemed to have been derived from her mother, who had probably acquired it by vinous potation; she applied a quack remedy to it, which I believe was a solution of lead, and was seized with epileptic fits, which terminated in palsy, and destroyed her. This shews the danger of using white paint on the face, which is called bismuth, but is in reality white lead or cerussa. Mr. Y---- had acquired the gutta rosea on his nose, and applied a saturnine solution on it for a few nights, and was then seized with paralysis on one side of his face; which however he gradually recovered, and has since acquired the gutta rosea on other parts of his face. These fatal effects were probably caused by the disagreeable sensation of an inflamed liver, which used before to be relieved of the sympathetic action and consequent inflammation of the skin of the face, which was now prevented by the stronger stimulus of the application of calx of lead. The manner in which disagreeable sensations induce epilepsy and palsy is treated of in Class III. In some cases where habitual discharges, or eruptions, or ulcers are stopped, a torpor of the system may follow, owing to the want of the accustomed quantity of sensation or irritation. See Class I. 1. 2. 9. and II. 1. 5. 6. In both these situations some other stimulus should be used to supply the place of that which is taken away; which may either be perpetual, as an issue; or periodical, as a cathartic repeated once a fortnight or month. Miss W. an elegant young lady of about twenty, applied a mercurial lotion to her face, which was covered with very small red points; which seemed to have been not acquired by any known or avoidable means; she was seized with inflammation of her liver, and after repeated bleeding and cathartics recovered, and in a few weeks the eruption appeared as before. M. M. Five grains of calomel once a month, with a cathartic, five grains of rhubarb and a quarter of a grain of emetic tartar every night for many weeks. With this preparation mercurial plasters, made without turpentine, and applied every night, and taken off every morning, will sometimes succeed, and may be used with safety. But blistering the face all over the eruption, beginning with a part, succeeds better than any other means, as I have more than once experienced.--Something like this is mentioned in the Letters of Lady Mary Wortley Montague, who blistered her face with balsam of Mecca. Mrs. F. had for many years had a disagreeably looking eruption on her chin, after a cathartic with calomel, she was advised to blister her whole chin; on the healing of the blister a few eruptions again appeared, which ceased on the application of a second blister. She took rhubarb five grains, and emetic tartar a quarter of a grain every night for many weeks. Miss L. a young lady about eighteen, had tried variety of advice for pimples over the greatest part of her face in vain. She took the above medicines internally, and blistered her face by degrees all over and became quite beautiful. A spot or two now and then appeared, and on this account she frequently slept with parts of her face covered with mercurial plaster, made without turpentine, which was held on by a pasteboard mask, and taken off in the mornings; if any part of the plaster adhered, a little butter or oil destroyed the adhesion. 7. _Odontitis._ Inflammatory tooth-ach is occasioned by inflammation of the membranes of the tooth, or a caries of the bone itself. The gum sometimes suppurates, otherwise a swelling of the cheek succeeds by association, and thus the violence of the pain in the membranes of the tooth is relieved, and frequently cured; and when this happens the disease properly belongs to Class IV. as it so far resembles the translations of morbid actions in the gout and rheumatism. At other times the tooth dies without caries, especially in people about sixty years of age, or before; and then it stimulates its involving membrane, like any other extraneous substance. The membrane then becomes inflamed and thickened, occasioning some pain, and the tooth rises upwards above the rest, and is gradually pushed out whole and undecayed; on its rising up a pus-like mucus is seen discharged from the gum, which surrounds it; and the gum seems to have left the tooth, as the fangs or roots of it are in part naked. M. M. Where the tooth is sound it can only be saved by evacuations by venesection, and a cathartic; and after its operation two grains of opium, a blister may also be used behind the ear, and ether applied to the cheek externally. In slighter cases two grains of opium with or without as much camphor may be held in the mouth, and suffered to dissolve near the affected tooth, and be gradually swallowed. See Class I. 2. 4. 12. Odontalgia may be distinguished from otitis by the application of cold water to the affected tooth; for as the pain of common tooth-ach is owing to torpor, whatever decreases stimulus adds to the torpor and consequent pain; whereas the pain of an inflamed tooth being ceased by the increased action of the membranes of it is in some measure alleviated by the application of cold. 8. _Otitis._ Inflammation and consequent suppuration of some membranes of the internal ear frequently occur in children, who sleep in cold rooms, or near a cold wall, without a night-cap. If the bones are affected, they come out in a long process of time, and the child remains deaf of that ear. But in this case there is generally a fever attends this inflammation; and it then belongs to another genus. M. M. A warmer night-cap. Warmish water should be gently syringed into the ear to keep it clean twice a day; and if it does not heal in a week, a little spirit of wine should be added; first about a fourth part, and it should be gradually increased to half rectified spirit and half water: if it continues long to discharge matter with a very putrid smell, the bones are injured, and will in time find their exit, during which time the ear should be kept clean by filling it with a weaker mixture of spirit of wine and water; or a solution of alum in water; which may be poured into the ear, as the head is inclined, and shook out again by turning the head, two or three times morning and evening. See Class II. 1. 4. 10. 9. _Fistula lacrymalis._ The lacrymal sack, with its puncta lacrymalia and nasal duct, are liable to be destroyed by suppuration without fever; the tears then run over the eyelids, and inflame the edges of them, and the cheeks, by their perpetual moisture, and saline acrimony. M. M. By a nice surgical operation a new aperture is to be made from the internal corner of the eye into the nostril, and a silver tube introduced, which supplies the defect by admitting the tears to pass again into the nostril. See Melanges de Chirurgie par M. Pouteau; who thinks he has improved this operation. 10. _Fistula in ano._ A mucous discharge from the anus, called by some white piles, or matter from a suppurated pile, has been mistaken for the matter from a concealed fistula. A bit of cotton wool applied to the fundament to receive the matter, and renewed twice a day for a week or two, should always be used before examination with the probe. The probe of an unskilful empyric sometimes does more harm in the loose cellular membrane of these parts than the original ulcer, by making a fistula he did not find. The cure of a fistula in ano of those, who have been much addicted to drinking spirituous liquor, or who have a tendency to pulmonary consumption, is frequently of dangerous consequence, and is succeeded by ulcers of the lungs, and death. M. M. Ward's paste, or 20 black pepper-corns taken after each meal twice a day; the pepper-corns should be cut each into two or three pieces. The late Dr. Monro of Edinburgh asserted in his lectures, that he had known a fistula in ano cured by injecting first a mixture of rectified spirit of wine and water; and by gradually increasing the strength of it, till the patient could bear rectified spirit alone; by the daily use of which at length the sides of the fistula became callous, and ceased to discharge, though the cavity was left. A French surgeon has lately affirmed, that a wire of lead put in at the external opening of the ulcer, and brought through the rectum, and twisted together, will gradually wear itself through the gut, and thus effect a cure without much pain. The ends of the leaden wire must be twisted more and more as it becomes loose. Or, lastly, it must be laid open by the knife. 11. _Fistula urethræ._ Where a stricture of the urethra exists, from whatever cause, the patient, in forcing the stream of urine through the structure, distends the urethra behind it; which after a time is liable to burst, and to become perforated; and some of the urine is pushed into the cellular membrane, occasioning fistulas, which sometimes have large surfaces producing much matter, which is pressed out at the time of making water, and has been mistaken for a catarrh of the bladder; these fistulas sometimes acquire an external opening in the perinæum, and part of the urine is discharged that way. Can this matter be distinguished from mucus of the bladder by the criterion delivered in Class II. 1. 6. 6? M. M. The perpetual use of bougies, either of catgut or of caoutchouc. The latter may be had at No. 37, Red-lion street, Holborn, London. The former are easily made, by moistening the catgut, and keeping it stretched till dry, and then rounding one end with a pen-knife. The use of a warm bath every day for near an hour, at the heat of 94 or 96 degrees, for two or three months, I knew to be uncommonly successful in one case; the extensive fistulas completely healing. The patient should introduce a bougie always before he makes water, and endeavour to make it as slowly as possible. See Class I. 2. 3. 24. 12. _Hepatitis chronica._ Chronical inflammation of the liver. A collection of matter in the liver has frequently been found on dissection, which was not suspected in the living subject. Though there may have been no certain signs of such a collection of matter, owing to the insensibility of the internal parts of this viscus; which has thus neither been attended with pain, nor induced any fever; yet there may be in some cases reason to suspect the existence of such an abscess; either from a sense of fulness in the right hypochondre, or from transient pains sometimes felt there, or from pain on pressure, or from lying on the left side, and sometimes from a degree of sensitive fever attending it. Dr. Saunders suspects the acute hepatitis to exist in the inflammation of the hepatic artery, and the chronical one in that of the vena portarum. Treatise on the Liver. Robinson. London. 13. _Scrophula suppurans._ Suppurating scrophula. The indolent tumors of the lymphatic glands are liable, after a long time, to regain their sensibility; and then, owing to their former torpor, an increased action of the vessels, beyond what is natural, with inflammation, is the consequence of their new life, and suppuration succeeds. This cure of scrophula generally happens about puberty, when a new energy pervades the whole system, and unfolds the glands and organs of reproduction. M. M. See Class I. 2. 3. 21. Where scrophulous ulcers about the neck are difficult to heal, Dr. Beddoes was informed, in Ireland, that an empyric had had some success by inflaming them by an application of wood sorrel, oxalis acetosella, the leaves of which are bruised in a mortar, and applied on the ulcers for two or three days, and then some more lenient application is used. A poor boy, about twelve years old, had a large scrophulous ulcer on one side of the chest beneath the clavicle, and another under his jaw; he was directed, about three weeks ago, to procure a pound of dry oak-bark from the tanners, and to reduce it to fine powder, and to add to it one ounce of white lead in fine powder, and to cover the ulcers daily with it, keeping it on by brown paper and a bandage. He came to me a few minutes ago, to shew me that both the ulcers are quite healed. The constant application of linen rags, moistened with a solution of an ounce of sugar of lead in a pint of water, I think I have seen equally efficacious. 14. _Scorbutus suppurans._ In the sea-scurvy there exists an inactivity of venous absorption, whence vibices and petechiæ, and sometimes ulcers. As the column of blood pressing on the of origins of the veins of the lower extremities, when the body is erect, opposes the ascent of the blood in them, they are more frequently liable to become enlarged, and to produce varixes, or vibices, or, lastly, ulcers about the legs, than on the upper parts of the body. The exposure to cold is believed to be another cause of ulcers on the extremities; as happens to many of the poor in winter at Lisbon, who sleep in the open air, without stockings, on the steps of their churches or palaces. See Class I. 2. 1. 15. M. M. A bandage spread with plaster to cover the whole limb tight. Rags dipped in a solution of sugar of lead. A warm flannel stocking or roller. White lead and oak bark, both in fine powder. Horizontal rest. 15. _Scirrhus suppurans._ When a scirrhus affects any gland of no great extent or sensibility, it is, after a long period of time, liable to suppurate without inducing fever, like the indolent tumors of the conglobate or lymphatic glands above mentioned; whence collections of matter are often found after death both in men and other animals; as in the liver of swine, which have been fed with the grounds of fermented mixtures in the distilleries. Another termination of scirrhus is in cancer, as described below. See Class I. 2. 3. 22. 16. _Carcinoma._ Cancer. When a schirrous tumor regains its sensibility by nature, or by any accidental hurt, new vessels shoot amongst the yet insensible parts of it, and a new secretion takes place of a very injurious material. This cancerous matter is absorbed, and induces swelling of the neighbouring lymphatic glands; which also become schirrous, and afterwards cancerous. This cancerous matter does not seem to acquire its malignant or contagious quality, till the cancer becomes an open ulcer; and the matter secreted in it is thus exposed to the air. Then it evidently becomes contagious, because it not only produces hectic fever, like common matter in ulcers open to the air; but it also, as it becomes absorbed, swells the lymphatic glands in its vicinity; as those of the axilla, when the open cancer is on the breast. See Class II. 1. 3. Hence exsection before the cancer is open is generally a cure; but after the matter has been exposed to the air, it is seldom of service; as the neighbouring lymphatic glands are already infected. I have observed some of these patients after the operation to have had diseased livers, which might either have previously existed, or have been produced by the fear or anxiety attending the operation. Erosion with arsenic, after the cancer is become an open ulcer, has generally no better effect than exsection, but has been successful before ulceration. The best manner of using arsenic, is by mixing one grain with a dram of lapis calaminaris, and strewing on the cancer some of the powder every day, till the whole is destroyed. Cancers on the face are said to arise from the periosteum, and that unless this be destroyed by the knife, or by caustics, the cancer certainly recurs. After the cancer becomes an open ulcer of some extent, a purulent fever supervenes, as from other open ulcers, and gradually destroys the patient. See Class II. 1. 6. 13. Two very interesting cases have been lately published by Dr. Ewart, of Bath, in which carbonic acid gas, or fixed air, was kept constantly in contact with the open cancerous ulcers of the breast; which then healed like other common ulcers. This is rather to be ascribed to the exclusion of oxygen, than to any specific virtue in the carbonic acid. As in common ulcers the matter does not induce hectic fever, till it has been exposed to the air, and then probably united with oxygen. The manner of applying the fixed air, is by including the cancer in one half or hemisphere of a large bladder; the edges are made to adhere to the skin by adhesive plaster, or perhaps a mixture of one part of honey with about twenty parts of carpenter's glue might better suit some tender skins. The bladder is then kept constantly filled with carbonic acid gas, by means of a pipe in the neck of it; and the matter let out at a small aperture beneath. 17. _Arthrocele._ Swelling of the joints seems to have its remote cause in the softness of the bones, for they could not swell unless they were previously softened, see Class I. 2. 2. 14. The epiphyses, or ends of the bones, being naturally of a looser texture, are most liable to this disease, and perhaps the cartilages and capsular ligaments may also become inflamed and swelled along with the heads of the bones. This malady is liable to distort the fingers and knees, and is usually called gout or rheumatism; the former of which is liable to disable the fingers by chalk-stones, and thence to have somewhat a similar appearance. But the arthrocele, or swelling of the joints, affects people who have not been intemperate in the use of fermented or spirituous liquors; or who have not previously had a regular gout in their feet; and in both these circumstances differs from the gout. Nor does it accord with the inflammatory rheumatism, as it is not attended with fever, and because the tumors of the joints never entirely subside. The pain or sensibility, which the bones acquire, when they are inflamed, may be owing to the new vessels, which shoot in them in their soft state, as well as to the distention of the old ones. M. M. Half a grain of opium twice a day, gradually increased to a grain, but not further, for many months. Thirty grains of powder of bark twice a day for many months. Ten grains of bone-ashes, or calcined hartshorn, twice a day, with decoction of madder? Soda phosphorata? 18. _Arthropuosis._ Joint-evil. This differs from the former, as that never suppurates; these ulcers of the joints are generally esteemed to arise from scrophula; but as scrophula is a disease of the lymphatic or absorbent system, and this consists in the suppuration of the membranes, or glands, or cartilages about the joints, there does not seem a sufficient analogy to authorize their arrangement under the same name. The white swelling of the knee, when it suppurates, comes under this species, with variety of other ulcers attended with carious bones. 19. _Caries ossium._ A caries of the bones may be termed a suppuration of them; it differs from the above, as it generally is occasioned by some external injury, as in decaying teeth; or by venereal virus, as in nodes on the tibia; or by other matter derived to the bone in malignant fevers; and is not confined to the ends of them. The separation of the dead bone from the living is a work of some time. See Sect. XXXIII. 3. 1. * * * * * ORDO I. _Increased Sensation._ GENUS V. _With the Production of new Vessels by external Membranes or Glands, without Fever._ The ulcers, or eruptions, which are formed on the external skin, or on the mouth or throat, or on the air-cells of the lungs, or on the intestines, all of which are more or less exposed to the contact of the atmospheric air, which we breathe, and which in some proportion we swallow with our food and saliva; or to the contact of the inflammable air, or hydrogen, which is set at liberty by the putrefying aliment in the intestines, or by putrefying matter in large abscesses; all of them produce contagious matter; which, on being inoculated into the skin of another person, will produce fever, or a similar disease. In some cases even the matter formed beneath the skin becomes in some degree contagious, at least so much so as to produce fever of the hectic or malignant kind, as soon as it has pierced through the skin, and has thus gained access to some kind of air; as the fresh puss of a common abscess; or the putrid pus of an abscess, which has been long confined; or of cancerous ulcers. From this analogy there is reason to suspect, that the matter of all contagious diseases, whether with or without fever, is not infectious till it has acquired something from the air; which, by oxygenating the secreted matter, may probably produce a new acid. And secondly, that in hectic fever a part of the purulent matter is absorbed; or acts on the surface of the ulcer; as variolous matter affects the inoculated part of the arm. And that hectic fever is therefore caused by the matter of an open ulcer; and not by the sensation in the ulcer independent of the aerated pus, which lies on it. Which may account for the venereal matter from buboes not giving the infection, according to the experiments of the late Mr. Hunter, and for some other phenomena of contagion. See Variola discreta, Class II. 1. 3. 9. SPECIES. 1. _Gonorrhoea venerea._ A pus-like contagious material discharged from the urethra after impure cohabitation, with smarting or heat on making water; which begins at the external extremity of the urethra, to which the contagious matter is applied, and where it has access to the air. M. M. In this state of the venereal disease once venesection, with mild cathartics of senna and manna, with mucilage, as almond emulsion, and gum arabic, taken for two or three weeks, absolve the cure. Is camphor of use to relieve the ardor urinæ? Do balsams increase or lessen the heat of urine? Neutral salts certainly increase the smarting in making water, by increasing the acrimony of the urine. Can the discharge from the urethra be soon stopped by saturnine injections, or mercurial ones, or with solution of blue vitriol, at first very dilute, and gradually made stronger? And at the same time lest the syphilis, or general disease, should supervene, the patient might take a quarter of a grain of corrosive sublimate of mercury twice a day, as directed below? 2. _Syphilis._ Venereal disease. The contagion shews itself in ulcers on the part first inoculated, as chancres; ulcers on the tonsils succeed, with eruption on the skin, especially about the roots of the hair; afterwards on other parts of the skin, terminating in dry scabs; and lastly, with pain and swelling of the bones. The corona veneris, or crown of Venus, consists of the eruptions at the roots of the hair appearing most round the forehead; which is occasioned by this part being more exposed to the air; which we observed, at the beginning of this genus, either produces or increases the virulence of contagious matter. But it is difficult to conceive from this history, why the throat should be first affected; as it cannot be supposed, that the disease is so often taken by the saliva, like the small-pox, though this may sometimes occur, perhaps very often. The connection between the genitals in men and the throat, is treated of in Class IV. 1. 2. 7. Hydrophobia. M. M. A quarter of a grain of corrosive sublimate of mercury, taken thrice a day for five or six weeks, made into a pill with breadcrumbs, or dissolved in a spoonful of brandy and water, is a very efficacious and almost certain cure. When it does not succeed, it is owing either to the drug being bad, or to its having precipitated from the brandy, or from its being spoiled in the pill by long keeping. Opium contributes much to expedite the cure both of the simple gonorrhoea, and of venereal ulcers, by increasing absorption both from the mucous membrane, and from the surface of ulcers. 3. _Lepra._ Leprosy. Leprosy of the Greeks. The skin is rough with white branny scales, which are full of chinks; often moist beneath, and itching. The scales on the head or arms of some drinking people are a disease of this kind. The perspirable matter designed for the purpose of lubricating the external skin is secreted in this disease in a too viscid state, owing to the inflammation of the subcutaneous vessels; and, as the absorbents act too strongly at the same time, a viscid mucus is left adhering to the surface of the skin. In the leprosy of the Jews, described in the thirteenth and fourteenth chapters of Leviticus, the depression of the sore beneath the surface of the skin, and the hairs in it becoming white, seem to have been the principal circumstances, which the priest was directed to attend to for the purpose of ascertaining the disease. M. M. Essence of antimony from 20 drops to 100 twice or thrice a day, with half a pint of decoction of elm-bark; or tincture of cantharides from 20 to 60 drops four times a day; or sublimate of mercury, with much diluting fluid. Acid of vitriol? Perhaps the cure chiefly depends on much dilution with water, from two to four pints a day, in which elm-bark, or pine-buds, or juniper-tops, may be boiled. Bath or Buxton water drank in large quantities. Warm bath. Oil-skin bound on the part to confine the perspirable matter. Ointment of tar and suet; or poultice for two or three days, and then cerate with lapis calaminaris. Diet of raisins and bread. Abstinence from wine, beer, and all spirits. 4. _Elephantiasis._ Leprosy of the Arabs. A contagious disease; the skin is thickened, wrinkled, rough, unctuous, destitute of hair, without any sensation of touch in the extremities of the limbs; the face deformed with tubercles; the voice hoarse, and with a nasal tone. Cullen. 5. _Framboesia._ Yaws is said to be contagious and hereditary. It principally affects the negroes in the West Indies. Edinb. Essays, Vol. VI. 6. _Psora._ Itch. A contagious prurient eruption. There are two kinds of itch, that which appears between the fingers, and under the joints of the knees and elbows; and that which seldom is seen in these places, but all over the other parts of the body. The latter is seldom thought to be the itch, as it does not easily infect even a bedfellow, and resists the usual means of cure by brimstone. If the itch be cured too hastily by rubbing mercurial or arsenical preparations over the whole body, or on too great a part of it, many bad symptoms are produced; as weakness of digestion, with pale bloated countenance, and tendency to dropsy. I have twice seen St. Vitus's dance occur from the use of a mercurial girdle; and once a swelled liver. I have also seen a swelled spleen and swelled legs from the external use of arsenic in the cure of the itch. And very numerous and large phlegmons commonly succeed the too hasty cure of it by other means. There does not appear a strict analogy between the hasty cure of the itch, and the retrocession of the pustles in the secondary fever of the small-pox; because in that the absorption of the matter is evinced by the swelling of the face and hands, as the pustles recede, as explained in Class II. 1. 3. 9. Variola discreta. And a fever is produced by this absorption; neither of which happen, when the pustles of the itch are destroyed by mercury or arsenic. Nor can these inconveniences, which occur on the too hasty cure of the itch, be explained by those which follow the cure of some kinds of gutta rosea, Class II. 1. 4. 6. as in those the eruptions on the face were an associated disease with inflammation of the liver or stomach, which they were accustomed to relieve; whereas the itch is not known to have had any previous catenation with other diseases. In the itch there exists not only great irritation in the production of the pustles, but great sensation is caused by their acrimony afterwards; insomuch that the pain of itching, without the interrupted smarting occasioned by scratching, would be intolerable. This great excitement of the two sensorial powers of irritation and sensation is so great, when the pustles are diffused over the whole surface of the body, that a torpor succeeds the sudden ceasing of it; which affects those parts of the system, which were most catenated with the new motions of the skin, as the stomach, whence indigestion and flatulency; or which are generally most liable to fall into torpor, as the numerous glands, which form the liver. Whence the diseases consequent to the hasty cure of the itch are diseases of debility, as tumid viscera, oedematous swellings, and St. Vitus's dance, which is a debility of association. In the same manner indigestion, with green evacuations, are said to follow an injudicious application of cerussa to stop too hastily the exsudation behind the ears of children, Class I. 1. 2. 9. And dropsies are liable to succeed the cure of old ulcers of the legs, which have long stimulated the system. M. M. The size of a large pea, of an ointment consisting of one part of white precipitate of mercury to six parts of hogs' lard well triturated together, to be rubbed on a part of the body every night, and washed off with soap and water next morning, till every part is cleared; with lac sulphuris twenty grains to be taken every morning inwardly. Warm saline bath, with white vitriol in it. Flowers of sulphur mixed with thick gruel, with hogs fat. With either of which the body may be smeared all over. 7. _Psora ebriorum._ Elderly people, who have been much addicted to spirituous drinks, as beer, wine, or alcohol, are liable to an eruption all over their bodies; which is attended with very afflicting itching, and which they probably propagate from one part of their bodies to another with their own nails by scratching themselves. I saw fatal effects in one such patient, by a too extensive use of a solution of lead; the eruption disappeared, he became dropsical, and died; I suppose from the too suddenly ceasing of the great stimulus caused by the eruptions over the whole skin, as in the preceding article. M. M. The patient should gradually accustom himself to half his usual quantity of vinous potation. The warm bath, with one pound of salt to every three gallons. Mercurial ointments on small parts of the skin at a time. A grain of opium at night instead of the usual potation of wine or beer. 8. _Herpes._ Herpes consists of gregarious spreading excoriations, which are succeeded by branny scales or scabs. In this disease there appears to be a deficient absorption of the subcutaneous mucus, as well as inflammation and increased secretion of it. For the fluid not only excoriates the parts in its vicinity by its acrimony, but is very saline to the taste, as some of these patients have assured me; I believe this kind of eruption, as well as the tinea, and perhaps all other cutaneous eruption, is liable to be inoculated in other parts of the body by the finger-nails of the patients in scratching themselves. It is liable to affect the hands, and to return at distant periods; and is probably a secondary disease, as well as the zona ignea, or shingles, described below. M. M. Poultice the eruption with bread and milk, or raw carrots grated, for two or three whole days, to dilute or receive the discharged fluid, and abate the inflammation; then cover the parts with fresh cerate mixed with lapis calaminaris. On the parts not excoriated mercurial ointment, made of one part of white calx of mercury and six of hogs' fat. Internally, after venesection, gentle repeated cathartics. Lastly, the bark. Acid of vitriol. Bolus Armeniæ, or testacia. Antimonials. Decoction of interior bark of elm. 9. _Zona ignea._ Shingles. This eruption has been thought a species of herpes by some writers, and by others a species of erysipelas. Yellow or livid vesicles appear, producing a corrosive ichor, which is sometimes attended with a degree of fever. It is said to infest sometimes the thorax and ribs, but its most general situation is on the small of the back, over one kidney, extending forward over the course of one of the ureters. There is reason to suspect, that this also is a secondary or sympathetic disease, as well as the preceding one; but future observations are required, before it can be removed to the fourth class, or diseases of association. In three patients I have been induced to believe, that the eruption on the loins was a translation of inflammation from the external membrane of the kidney to the skin. They had, for a day or two before the appearance of the eruption, complained of a dull pain on the region of one kidney, but without vomiting; by which it was distinguished from nephritis interna, or gravel; and without pain down the outside of the thigh, by which it was distinguished from sciatica. In other situations the shingles may sympathize with other internal membranes, as in a case published by Dr. Russel (De Tabe Glandulari), where the retrocession of the shingles was succeeded by a serious dyspnæa. M. M. Venesection, if the pulse is strong. Calomel three or four grains, very mild repeated cathartics. Poultice for a few days, then cerate of lapis calaminaris, as in herpes. A grain of emetic tartar dissolved in a pint of water, and taken so as to empty the stomach and intestines, is said much to hasten the cure; compresses soaked in a saturnine solution are recommended externally on the eruption; and cerate where there are ulcerations. Desanet's Surgical Journal, Vol. II. p. 378. If this be a vicarious disease, it should continue half a lunation; lest, on its ceasing, the bad habits of motion of the primary disease should not have been so perfectly dissevered, but that they may recur. 10. _Annulus repens._ Ring-worm. A prurient eruption formed in a circle, affecting children, and would seem to be the work of insects, according to the theory of Linnæus, who ascribes the itch and dysentery to microscopic animalcula. These animalcula are probably the effect, and not the cause, of these eruptions; as they are to be seen in all putrescent animal fluids. The annular propagation of the ring-worm, and its continuing to enlarge its periphery, is well accounted for by the acrimony of the ichor or saline fluid eroding the skin in its vicinity. M. M. Cover the eruption daily with ink. With white mercurial ointment, as described above in herpes. With solution of white vitriol ten grains to an ounce. These metallic calces stimulate the absorbents into stronger action, whence the fluid has its saline part reabsorbed, and that before it has access to the air, which probably adds to its acrimony by oxygenating it, and thus, producing a new acid. 11. _Tinea._ Scald head. This contagious eruption affects the roots of the hair, and is generally most virulent around the edges of the hair on the back part of the head; as the corona veneris appears most on the edges of the hair on the forepart of the head; for in these parts the eruption about the roots of the hair is most exposed to the external air, by which its acrimony or noxious quality is increased. The absorption of the matter thus oxygenated swells the lymphatics of the neck by its stimulus, occasioning many little hard lumps beneath the seat of the eruption; when this happens, the sooner it is cured the better, lest the larger lymphatics of the neck should become affected. M. M. The art of curing these eruptions consists, first, in abating the inflammation, and consequent secretion of a noxious material. Secondly, to prevent its access to the air, which so much increases its acrimony. And thirdly, to promote the absorption of it, before it has been exposed to the air; for these purposes venesection once, and gentle cathartics, which promote absorption by emptying the blood-vessels. Next poultices and fomentations, with warm water, abate inflammation by diluting the saline acrimony of the secreted fluid, and abating the painful sensation. Afterwards cerate joined with some metallic calx, as of zinc or lead, or solution of lead, mercury, or copper, or iron, which may stimulate the absorbent system into stronger action. Cover the shaved head with tar and suet, and a bladder; this, by keeping the air from the secreted fluid, much contributes to its mildness, and the stimulus of the tar increases its absorption. See the three preceding species of this genus. 12. _Crusta lactea._ Milk-crust is a milder disease than tinea, affecting the face as well as the hairy scalp of very young children. It is not infectious, nor liable to swell the lymphatics in its vicinity like the tinea. M. M. Cover the eruption with cerate made with lapis calaminaris, to be renewed every day. Mix one grain of emetic tartar with forty grains of chalk, and divide into eight papers, one to be taken twice a day, or with magnesia alba, if stools are wanted. The child should be kept cool and much in the air. 13. _Trichoma._ Plica polonica. A contagious disease, in which the hair is said to become alive and bleed, forming inextricable knots or plaits of great length, like the fabled head of Medusa, with intolerable pain, so as to confine the sufferer on his bed for years. * * * * * ORDO I. _Increased Sensation._ GENUS VI. _With Fever consequent to the Production of new Vessels or Fluids._ SPECIES. 1. _Febris sensitiva._ Sensitive fever, when unmixed with either irritative or inirritative fever, may be distinguished from either of them by the less comparative diminution of muscular strength; or in other words, from its being attended with less diminution of the sensorial power of irritation. An example of unmixed sensitive fever may generally be taken from the pulmonary consumption; in this disease patients are seen to walk about with ease, and to do all the common offices of life for weeks, and even months, with a pulse of 120 strokes in a minute; while in other fevers, whether irritated or inirritated, with a pulse of this frequency, the patient generally lies upon the bed, and exerts no muscular efforts without difficulty. The cause of this curious phenomenon is thus to be understood; in the sensitive fever a new sensorial power, viz. that of sensation, is superadded to that of irritation; which in other fevers alone carries on the increased circulation. Whence the power of irritation is not much more exhausted than in health; and those muscular motions, which are produced in consequence of it, as those which are exerted in keeping the body upright in walking, riding, and in the performance of many customary actions, are little impaired. For an account of the irritated sensitive fever, see Class II. 1. 2. 1.; for the inirritated sensitive fever, Class II. 1. 3. 1. IV. 2. 4. 11. 2. _Febris a pure clauso._ Fever from inclosed matter is generally of the irritated sensitive kind, and continues for many weeks, and even months, after the abscess is formed; but is distinguished from the fever from aerated matter in open ulcers, because there are seldom any night-sweats, or colliquative diarrhoea in this, as in the latter. The pulse is also harder, and requires occasional venesection, and cathartics, to abate the inflammatory fever; which is liable to increase again every three or four days, till at length, unless the matter has an exit, it destroys the patient. In this fever the matter, not having been exposed to the air, has not acquired oxygenation; in which a new acid, or some other noxious property, is produced; which acts like contagion on the constitution inducing fever-fits, called hectic fever, which terminate with sweats or diarrhoea; whereas the matter in the closed abscess is either not absorbed, or does not so affect the circulation as to produce diurnal or hectic fever-fits; but the stimulus of the abscess excites so much sensation as to induce perpetual pyrexia, or inflammatory fever, without such marked remissions. Nevertheless there sometimes is no fever produced, when the matter is lodged in a part of little sensibility, as in the liver; yet a white pus-like sediment in those cases exists I believe generally in the urine, with occasional wandering pains about the region of the liver or chest. 3. _Vomica._ An abscess in the lungs is sometimes produced after peripneumony, the cough and shortness of breath continue in less degree, with difficulty in lying on the well side, and with sensitive irritated fever, as explained in the preceding article. The occasional increase of fever, with hard pulse and sizy blood, in these patients, is probably owing to the inflammation of the walls of the vomica; as it is attended with difficulty of breathing, and requires venesection. Mr. B----, a child about seven years old, lived about five weeks in this situation, with a pulse from 150 to 170 in a minute, without sweats, or diarrhoea, or sediment in his water, except mucus occasionally; and took sufficient nourishment during the whole time. The blood taken was always covered with a strong cupped size, and on his death three or four pints of matter were found in one side of the chest; which had probably, but lately, been effused from a vomica. This child was frequently induced to swing, both in a reciprocating and in a rotatory swing, without any apparent absorption of matter; in both these swings he expressed pleasure, and did not appear to be vertiginous. M. M. Repeated emetics. Digitalis? Perseverance in rotatory swinging. See Class II. 1. 6. 7. Mr. I. had laboured some months under a vomica after a peripneumony, he was at length taken with a catarrh, which was in some degree endemic in March 1795, which occasioned him to sneeze much, during which a copious hæmorrhage from the lungs occurred, and he spit up at the same time half a pint of very fetid matter, and recovered. Hence errhines may be occasionally used with advantage. 4. _Empyema._ When the matter from an abscess in the lungs finds its way into the cavity of the chest, it is called an empyema. A servant man, after a violent peripneumony, was seized with symptoms of empyema, and it was determined, after some time, to perform the operation; this was explained to him, and the usual means were employed by his friends to encourage him, "by advising him not to be afraid." By which good advice he conceived so much fear, that he ran away early next morning, and returned in about a week quite well. Did the great fear promote the absorption of the matter, like the sickness occasioned by digitalis? Fear renders the external skin pale; by this continued decrease of the action of the absorbents of the skin might not those of the lungs be excited into greater activity? and thus produce increased pulmonary absorption by reverse sympathy, as it produces pale urine, and even stools, by direct sympathy? M.M. Digitalis? 5. _Febris Mesenterica._ Fever from matter formed in the mesentery is probably more frequent than is suspected. It commences with pain in the bowels, with irritated sensitive fever; and continues many weeks, and even months, requiring occasional venesection, and mild cathartics; till at length the continuance of the pyrexia, or inflammatory fever, destroys the patient. This is an affection of the lymphatic glands, and properly belongs to scrophula; but as the matter is not exposed to the air, no hectic fever, properly so called, is induced. 6. _Febris a pure aerato._ Fever from aerated matter. A great collection of matter often continues a long time, and is sometimes totally absorbed, even from venereal buboes, without producing any disorder in the arterial system. At length, if it becomes putrid by its delay, and one part of the matter thus becomes aerated by the air given out by the other part; or if the ulcer has been opened, so that any part of it has been exposed to the air for but one day, a hectic fever is produced. Whence the utility arises of opening large abscesses by setons, as in that case little or no hectic fever is induced; because the matter is squeezed out by the side of the spongy threads of cotton, and little or no air is admitted; or by tapping the abscess with a trocar, as mentioned in ischias, Class II. 1. 2. 18. In this fever the pulse is about 120 in a minute, and its access is generally in an evening, and sometimes about noon also, with sweats or purging towards morning, or urine with pus-like sediment; and the patients bear this fever better than any other with so quick a pulse; and lastly, when all the matter from a concealed ulcer is absorbed, or when an open ulcer is healed, the hectic fever ceases. Here the absorbed matter is supposed to produce the fever, and the diarrhoea, sweats, or copious muddy urine, to be simply the consequence of increased secretion, and not to consist of the purulent matter, which was supposed to be absorbed from the ulcer. See Sudor calidus, Class I. 1. 2. 3. The action of the air on ulcers, as we have already shewn, increases the acrimony of the purulent matter, and even converts it into a weaker kind of contagious matter; that is, to a material inducing fever. This was ascribed to the union of the azotic part of the atmosphere with the effused pus in Sect. XXVIII. 2. but by contemplating more numerous facts and analogies, I am now induced to believe, that it is by the union of oxygen with it; first, because oxygen so greedily unites with other animal substances, as the blood, that it will pass through a moist bladder to combine with it, according to the experiment of Dr. Priestley. Secondly, because the poisons of venomous creatures are supposed to be acids of different kinds, and are probably formed by the contact of air after their secretion. And lastly, because the contagious matter from other ulcers, as in itch, or small-pox, are formed on external membranes, and are probably combinations of animal matter and oxygen, producing other new acids; but further experiments must determine this question. It was thought a subject of consequence by the Æsculapian Society at Edinburgh, to find a criterion which should distinguish pus from mucus, for the purpose of more certainly discovering the presence of ulcers in pulmonary diseases, or in the urinary passages. For this purpose that society offered their first gold medal, which was conferred on the late Mr. Charles Darwin, in the year 1778, for his experiments on this subject. From which he deduces the following conclusions: "1. Pus and mucus are both soluble in the vitriolic acid, though in very different proportions, pus being much the less soluble. 2. The addition of water to either of these compounds decomposes it; the mucus thus separated, either swims on the mixture, or forms large flocci in it; whereas the pus falls to the bottom, and forms on agitation a uniform turbid mixture. 3. Pus is diffusible through a diluted vitriolic acid, though mucus is not; the same occurs with water, or a solution of sea salt. 4. Nitrous acid dissolves both pus and mucus; water added to the solution of pus produces a precipitate; and the fluid above becomes clear and green; while water and the solution of mucus form a dirty coloured fluid. 5. Alkaline lixivium dissolves (though sometimes with difficulty) mucus, and generally pus. 6. Water precipitates pus from such a solution, but does not mucus. 7. Where alkaline lixivium does not dissolve pus, it still distinguishes it from mucus; as it then prevents its diffusion through water. 8. Coagulable lymph is neither soluble in diluted nor concentrated vitriolic acid. 9. Water produces no change on a solution of serum in alkaline lixivium, until after long standing, and then only a very slight sediment appears. 10. Corrosive sublimate coagulates mucus, but does not pus. From the above experiments it appears, that strong vitriolic acid and water, diluted vitriolic acid, and caustic alkaline lixivium and water will serve to distinguish pus from mucus; that the vitriolic acid can separate it from coagulable lymph, and alkaline lixivium from serum. And hence, when a person has any expectorated material, the composition of which he wishes to ascertain, let him dissolve it in vitriolic acid, and in caustic alkaline lixivium; and then add pure water to both solutions: and if there is a fair precipitation in each, he may be assured that some pus is present. If in neither a precipitation occurs, it is a certain test, that the material is entirely mucus. If the material cannot be made to dissolve in alkaline lixivium by time and trituration, we have also reason to believe that it is pus." Experiments on Pus and Mucus. Cadell. London. 7. _Phthisis pulmonalis._ In pulmonary consumption the fever is generally supposed to be the consequence of the stimulus of absorbed matter circulating in the blood-vessels, and not simply of its stimulus on their extremities in the surface of the ulcers; as mentioned in Class II. 1. 5. and Class II. 1. 3. 9. The ulcers are probably sometimes occasioned by the putrid acrimony of effused blood remaining in the air-cells of the lungs after an hæmoptoe. See Class I. 2. 1. 9. The remote cause of consumption is ingeniously ascribed by Dr. Beddoes to the hyper-oxygenation of the blood, as mentioned Section XXVIII. 2. As the patients liable to consumption are of the inirritable temperament, as appears by the large pupils of their eyes; there is reason to believe, that the hæmoptoe is immediately occasioned by the deficient absorption of the blood at the extremities of the bronchial vein; and that one difficulty of healing the ulcers is occasioned by the deficient absorption of the fluids effused into them. See Sect. XXX. 1. and 2. The difficulty of healing pulmonary ulcers may be owing, as its remote cause, to the incessant motion of all the parts of the lungs; whence no scab, or indurated mucus, can be formed so as to adhere on them. Whence these naked ulcers are perpetually exposed to the action of the air on their surfaces, converting their mild purulent matter into a contagious ichor; which not only prevents them from healing, but by its action on their circumferences, like the matter of itch or tinea, contributes to spread them wider. See the preceding article, and Sect. XXXIII. 2. 7. where the pulmonary phthisis is supposed to be infectious. This acidifying principle is found in all the metallic calces, as in lapis calaminaris, which is a calciform ore of zinc; and in cerussa, which is a calx of lead; two materials which are powerful in healing excoriations, and ulcers, in a short time by their external application. How then does it happen, that the oxygen in the atmosphere should prevent pulmonary ulcers from healing, and even induce them to spread wider; and yet in its combination with metals, it should facilitate their healing? The healing of ulcers consists in promoting the absorption of the fluids effused into them, as treated of in Section XXXIII. 3. 2. Oxygen in combination with metals, when applied in certain quantity, produces this effect by its stimulus; and the metallic oxydes not being decomposed by their contact with animal matter, no new acid, or contagious material, is produced. So that the combined oxygen, when applied to an ulcer, simply I suppose promotes absorption in it, like the application of other materials of the articles sorbentia or incitantia, if applied externally; as opium, bark, alum. But in the pulmonary ulcers, which cannot protect themselves from the air by forming a scab, the uncombined oxygen of the atmosphere unites with the purulent matter, converting it into a contagious ichor; which by infection, not by erosion, enlarges the ulcers, as in the itch or tinea; which might hence, according to Dr. Beddoes's ingenious theory of consumption, be induced to heal, if exposed to an atmosphere deprived of a part of its oxygen. This I hope future experiments will confirm, and that the pneumatic medicine will alleviate the evils of mankind in many other, as well as in this most fatal malady. M. M. First, the respiration of air lowered by an additional quantity of azote, or mixed with some proportion of hydrogen, or of carbonic acid air, may be tried; as described in a late publication of Dr. Beddoes on the medicinal use of factitious airs. Johnson, London. Or lastly, by breathing a mixture of one tenth part of hydro-carbonate mixed with common air, according to the discovery of Mr. Watt, which has a double advantage in these cases, of diluting the oxygen of the atmospheric air, and inducing sickness, which increases pulmonary absorption, as mentioned below. An atmosphere diluted with fixed air (carbonic acid) might be readily procured by setting tubs of new wort, or fermenting beer, in the parlour and lodging-room of the patient. For it is not acids floating in the air, but the oxygen or acidifying principle, which injures or enlarges pulmonary ulcers by combining with the purulent matter. Another easy method of adding carbonic acid gas to the air of a room, would be by means of an apparatus invented by Mr. Watt, and sold by Bolton and Watt at Birmingham, as described in Dr. Beddoes' Treatise on Pneumatic Medicine. Johnson, London. It consists of an iron pot, with an arm projecting, and a method of letting water drop by slow degrees on chalk, which is to be put into the iron pot, and exposed to a moderate degree of heat over a common fire. By occasionally adding more and more chalk, carbonic acid gas might be carried through a tin pipe from the arm of the iron pot to any part of the room near the patient, or from an adjoining room. In the same manner a diffusion of solution of flowers of zinc might be produced and breathed by the patient, and would be likely much to contribute to the healing of pulmonary ulcers; as observed by Mr. Watt. See the treatise above mentioned. Breathing over the vapour of caustic volatile alkali might easily be managed for many hours in a day; which might neutralize the acid poison formed on pulmonary ulcers by the contact of oxygen, and thus prevent its deleterious quality, as other acids become less caustic, when they are formed into neutral salts with alkalis. The volatile salt should be put into a tin canister, with two pipes like horns from the top of it, one to suck the air from, and the other to admit it. [Illustration] Secondly, the external ulcers in scrophulous habits are pale and flabby, and naturally disinclined to heal, the deposition of fluids in them being greater than the absorption; these ulcers have their appearance immediately changed by the external application of metallic calxes, and the medicines of the article Sorbentia, such as cerussa and the bark in fine powder, see Class I. 2. 3. 21. and are generally healed in a short time by these means. Induced by these observations, I wished to try the external application of such powders to ulcers in the lungs, and constructed a box with a circulating brush in it, as described in the annexed plate; into this box two ounces of fine powder of Peruvian bark were put, and two drams of cerussa in fine powder; on whirling the central brush, part of this was raised into a cloud of powder, and the patient, applying his mouth to one of the tin pipes rising out of the box, inhaled this powder twice a day into his lungs. I observed it did not produce any cough or uneasiness. This patient was in the last stage of consumption, and was soon tired of the experiment, nor have I had such patients as I wished for the repetition of it. Perhaps a fine powder of manganese, or of the flowers of zinc, or of lapis calaminaris, might be thus applied to ulcers of the lungs with greater advantage? Perhaps air impregnated with flowers of zinc in their most comminuted state, might be a better way of applying this powder to the lungs, as discovered by Mr. Watt. See Dr. Beddoes on Pneumatic Medicine. Johnson. Thirdly, as the healing of an ulcer consists in producing a tendency to absorption on its surface greater than the deposition on it; see Sect. XXXIII. 3. 2. other modes of increasing pulmonary absorption, which are perhaps more manageable than the preceding ones, may be had recourse to; such as by producing frequent nausea or sickness. See Sect. XXIX. 5. 1. and Art. IV. 2. The great and sudden absorption of fluid from the lungs in the anasarca pulmonum by the sickness induced by the exhibition of digitalis, astonishes those who have not before attended to it, by emptying the swelled limbs, and removing the difficulty of breathing in a few hours. The most manageable method of using digitalis is by making a saturated tincture of it, by infusing two ounces of the powder of the leaves in a mixture of four ounces of rectified spirit of wine, and four ounces of water. Of this from 30 to 60 drops, or upwards, from a two-ounce phial, are to be taken twice in the morning part of the day, and to be so managed as not to induce violent sickness. If sickness nevertheless comes on, the patient must for a day or two omit the medicine; and then begin it again in reduced doses. Mr. ----, a young man about twenty, with dark eyes, and large pupils, who had every symptom of pulmonary ulcers, I believed to have been cured by digitalis, and published the case in the Transactions of the College, Vol. III. But about two years afterwards I heard that he relapsed and died. Mr. L----, a corpulent man, who had for some weeks laboured under a cough with great expectoration, with quick pulse, and difficulty of breathing, soon recovered by the use of digitalis taken twice a day; and though this case might probably be a peripneumonia notha, or catarrh, it is here related as shewing the power of pulmonary absorption excited by the use of this drug. Another method of inducing sickness, and pulmonary absorption in consequence, is by sailing on the sea; by which many consumptive patients have been said to have received their cure; which has been erroneously ascribed to sea-air, instead of sea-sickness; whence many have been sent to breathe the sea-air on the coasts, who might have done better in higher situations, where the air probably contains less oxygen gas, which is the heaviest part of it. See a Letter from Dr. T. C. below. A third method of inducing sickness, and consequent pulmonary absorption, is by the vertigo occasioned by swinging; which has lately been introduced into practice by Dr. Smith, (Essay on Pulmonary Consumption), who observed that by swinging the hectic pulse became slower, which is explained in Class IV. 2. 1. 10. The usual way of reciprocating swinging, like the oscillations of a pendulum, produces a degree of vertigo in those, who are unused to it; but to give it greater effect, the patient should be placed in a chair suspended from the ceiling by two parallel cords in contact with each other, the chair should then be forcibly revolved 20 or 40 times one way, and suffered to return spontaneously; which induces a degree of sickness in most adult people, and is well worthy an exact and pertinacious trial, for an hour or two, three or four times a day for a month. The common means of promoting absorption in ulcers, and of thickening the matter in consequence, by taking the bark and opium internally, or by metallic salts, as of mercury, steel, zinc, and copper, in small quantities, have been repeatedly used in pulmonary consumption; and may have relieved some of the symptoms. As mercury cures venereal ulcers, and as pulmonary ulcers resemble them in their not having a disposition to heal, and in their tendency to enlarge themselves, there were hopes, from analogy, that it might have succeeded. Would a solution of gold in aqua regia be worth trying? When vinegar is applied to the lips, it renders them instantly pale, by promoting the venous absorption; if the whole skin was moistened with warmish vinegar, would this promote venous absorption in the lungs by their sympathy with the skin? The very abstemious diet on milk and vegetables alone is frequently injurious. Flesh-meat once a day, with small wine and water, or small beer, is preferable. Half a grain of opium twice a day, or a grain, I believe to be of great use at the commencement of the disease, as appears from the subsequent case. Miss ----, a delicate young lady, of a consumptive family, when she was about eighteen, had frequent cough, with quick pulse, a pain of her side, and the general appearances of a beginning consumption. She took about five drops of laudanum twice a day in a saline draught, which was increased gradually to ten. In a few weeks she recovered, was afterwards married, bore three or four children, and then became consumptive and died. The following case of hereditary consumption is related by a physician of great ability and very extensive practice; and, as it is his own case, abounds with much nice observation and useful knowledge; and, as it has been attended with a favourable event, may give consolation to many, who are in a similar situation; and shews that Sydenham's recommendation of riding as a cure for consumption is not so totally ineffectual, as is now commonly believed. "J. C. aged 27, with black hair, and a ruddy complexion, was subject to cough from the age of puberty, and occasionally to spitting of blood. His maternal grandfather died of consumption under thirty years of age, and his mother fell a victim to this disease, with which she had long been threatened, in her 43d year, and immediately after she ceased to have children. In the severe winter of 1783-4, he was much afflicted with cough; and being exposed to intense cold, in the month of February he was seized with peripneumony. The disease was violent and dangerous, and after repeated bleedings as well as blisterings, which he supported with difficulty, in about six weeks he was able to leave his bed. At this time the cough was severe, and the expectoration difficult. A fixed pain remained on the left side, where an issue was inserted; regular hectic came on every day about an hour after noon, and every night heat and restlessness took place, succeeded towards morning by general perspiration. The patient, having formerly been subject to ague, was struck with the resemblance of the febrile paroxysm, with what he had experienced under that disease, and was willing to flatter himself it might be of the same nature. He therefore took bark in the interval of fever, but with an increase of his cough, and this requiring venesection, the blood was found highly inflammatory. The vast quantity of blood which he had lost from time to time, produced a disposition to fainting, when he resumed the upright posture, and he was therefore obliged to remain almost constantly in a recumbent position. Attempting to ride out in a carriage, he was surprised to find that he could sit upright for a considerable time, while in motion, without inconvenience, though, on stopping the carriage, the disposition to fainting returned. At this time, having prolonged his ride beyond the usual length, he one day got into an uneven road at the usual period of the recurrence of the hectic paroxysms, and that day he missed it altogether. This circumstance led him to ride out daily in a carriage at the time the febrile accession might be expected, and sometimes by this means it was prevented, sometimes deferred, and almost always mitigated. This experience determined him to undertake a journey of some length, and Bristol being, as is usual in such cases, recommended, he set out on the 19th of April, and arrived there on the 2d of May. During the greater part of this journey (of 175 miles) his cough was severe, and being obliged to be bled three different times on the road, he was no longer able to sit upright, but at very short intervals, and was obliged to lie at length in the diagonal of a coach. The hectic paroxysms were not interrupted during the journey, but they were irregular and indistinct, and the salutary effects of exercise, or rather of gestation, were impressed on the patient's mind. At Bristol he stayed a month, but reaped no benefit. The weather was dry and the roads dusty; the water insipid and inert. He attempted to ride on horseback on the downs, but was not able to bear the fatigue for a distance of more than a hundred yards. The necessity of frequent bleedings kept down his strength, and his hectic paroxysms continued, though less severe. At this time, suspecting that his cough was irritated by the west-winds bearing the vapour from the sea, he resolved to try the effects of an inland situation, and set off for Matlock in Derbyshire. During the journey he did not find the improvement he expected, but the nightly perspirations began to diminish; and the extraordinary fatigue he experienced proceeded evidently from his travelling in a post-chaise, where he could not indulge in a recumbent position. The weather at Bristol had been hot, and the earth arid and dusty. At Matlock, during the month of June 1784, there was almost a perpetual drizzle, the soil was wet, and the air moist and cold. Here, however, the patient's cough began to abate, and at intervals he found an opportunity of riding more or less on horseback. From two or three hundred yards at a time, he got to ride a mile without stopping; and at length he was able to sit on horseback during a ride from Mason's Bath to the village of Matlock along the Derwent, and round on the opposite banks, by the works of Mr. Arkwright, back to the house whence he started, a distance of five miles. On dismounting, however, he was seized with diliquium, and soon after the strength he had recovered was lost by an attack of the hæmorrhoids of the most painful kind, and requiring much loss of blood from the parts affected. On reflection, it appeared that the only benefit received by the patient was during motion, and continued motion could better be obtained in the course of a journey than during his residence at any particular place. This, and other circumstances of a private but painful nature, determined him to set out from Matlock on a journey to Scotland. The weather was now much improved, and during the journey he recruited his strength. Though as yet he could not sit upright at rest for half an hour together without a disposition to giddiness, dimness of sight, and deliquium, he was able to sit upright under the motion of a post-chaise during a journey of from 40 to 70 miles daily, and his appetite began to improve. Still his cough continued, and his hectic flushings, though the chills were much abated and very irregular. The salutary effects of motion being now more striking than ever, he purchased a horse admirably adapted to a valetudinarian in Dumfriesshire, and being now able to sit on horseback for an hour together, he rode out several times a day. He fixed his residence for a few weeks at Moffat, a village at the foot of the mountains whence the Tweed, the Clyde, and the Annan, descend in different directions; a situation inland, dry, and healthy, and elevated about three hundred feet above the surface of the sea. Here his strength recovered daily, and he began to eat animal food, which for several months before he had not tasted. Persevering in exercise on horseback, he gradually increased the length of his rides, according to his strength, from four to twenty miles a day; and returning on horseback to Lancashire by the lakes of Cumberland, he arrived at Liverpool on the first of September, having rode the last day of his journey forty miles. The two inferences of most importance to be drawn from this narrative, are, first, the extraordinary benefit derived from gestation in a carriage, and still more the mixture of gestation and exercise on horseback, in arresting or mitigating the hectic paroxysm; and secondly, that in the florid consumption, as Dr. Beddoes terms it, an elevated and inland air is in certain circumstances peculiarly salutary; while an atmosphere loaded with the spray of the sea is irritating and noxious. The benefit derived in this case from exercise on horseback, may lead us to doubt whether Sydenham's praise of this remedy be as much exaggerated as it has of late been supposed. Since the publication of Dr. C. Smyth on the effects of swinging in lowering the pulse in the hectic paroxysm, the subject of this narrative has repeated his experiments in a great variety of cases, and has confirmed them. He has also repeatedly seen the hectic paroxysm prevented, or cut short, by external ablution of the naked body with tepid water. So much was his power of digestion impaired or vitiated by the immense evacuations, and the long continued debility he underwent, that after the cough was removed, and indeed for several years after the period mentioned, he never could eat animal food without heat and flushing, with frequent pulse and extreme drowsiness. If this drowsiness was encouraged, the fever ran high, and he awoke from disturbed sleep, wearied and depressed. If it was resolutely resisted by gentle exercise, it went off in about an hour, as well as the increased frequency of the pulse. This agitation was however such as to incapacitate him during the afternoon for study of any kind. The same effects did not follow a meal of milk and vegetables, but under this diet his strength did not recruit; whereas after the use of animal food it recovered rapidly, notwithstanding the inconvenience already mentioned. For this inconvenience he at last found a remedy in the use of coffee immediately after dinner, recommended to him by his friend Dr. Percival. At first this remedy operated like a charm, but by frequent use, and indeed by abuse, it no longer possesses its original efficacy. Dr. Falconer, in his Dissertation on the Influence of the Passions and Affections of the Mind on Health and Disease, supposes that the cheerfulness which attends hectic fever, the ever-springing hope, which brightens the gloom of the consumptive patient, increases the diseased actions, and hastens his doom. And hence he is led to enquire, whether the influence of fear might not be substituted in such cases to that of hope with advantage to the patient? This question I shall not presume to answer, but it leads me to say something of the state of the mind in the case just related. The patient, being a physician, was not ignorant of his danger, which, some melancholy circumstances served to impress on his mind. It has already been mentioned, that his mother and grandfather died of this disease. It may be added, that in the year preceding that on which he himself was attacked, a sister of his was carried off by consumption in her 17th year; that in the same winter in which he fell ill, two other sisters were seized with the same fatal disorder, to which one of them fell a victim during his residence at Bristol, and that the hope of bidding a last adieu to the other was the immediate cause of his journey to Scotland, a hope which, alas! was indulged in vain. The day on which he reached the end of his journey, her remains were committed to the dust! It may be conjectured from these circumstances, that whatever benefit may be derived from the apprehension of death, must in this case have been obtained. The expectation of this issue was indeed for some time so fixed that it ceased to produce much agitation; in conformity to that general law of our nature, by which almost all men submit with composure to a fate that is foreseen, and that appears inevitable. As however the progress of disease and debility seemed to be arrested, the hope and the love of life revived, and produced, from time to time, the observations and the exertions already mentioned. Wine and beer were rigorously abstained from during six months of the above history; and all the blood which was taken was even to the last buffy." Feb. 3, 1795. 8. _Febris scrophulosa._ The hectic fever occasioned by ulcers of the lymphatic glands, when exposed to the air, does not differ from that attending pulmonary consumption, being accompanied with night-sweats and occasional diarrhoea. M. M. The bark. Opium internally. Externally cerussa and bark in fine powder. Bandage. Sea-bathing. See Class I. 2. 3. 21. and II. 1. 4. 13. 9. _Febris ischiadica._ A hectic fever from an open ulcer between the muscles of the pelvis, which differs not from the preceding. If the matter in this situation lodges till part of it, I suppose, becomes putrid, and aerates the other part; or till it becomes absorbed from some other circumstance; a similar hectic fever is produced, with night-sweats, or diarrhoea. Mrs. ----, after a lying in, had pain on one side of her loins, which extended to the internal part of the thigh on the same side. No fluctuation of matter could be felt; she became hectic with copious night-sweats, and occasional diarrhoea, for four or five weeks; and recovered by, I suppose, the total absorption of the matter, and the reunion of the walls of the abscess. See Class II. 1. 2. 18. 10. _Febris Arthropuodica._ Fever from the matter of diseased joints. Does the matter from suppurating bones, which generally has a very putrid smell, produce hectic fever, or typhus? See Class II. 1. 4. 16. 11. _Febris a pure contagioso._ Fever from contagious pus. When the contagious matters have been produced on the external habit, and in process of time become absorbed, a fever is produced in consequence of this reabsorption; which differs with the previous irritability or inirritability, as well as with the sensibility of the patient. 12. _Febris variolosa secundaria._ Secondary fever of small-pox. In the distinct small-pox the fever is of the sensitive irritated or inflammatory kind; in the confluent small-pox it is of the sensitive inirritated kind, or typhus gravior. In both of them the swelling of the face, when the matter there begins to be absorbed, and of the hands, when the matter there begins to be absorbed, shew, that it stimulates the capillary vessels or glands, occasioning an increased secretion greater than the absorbents can take up, like the action of the cantharides in a blister; now as the application of a blister on the skin frequently occasions the strangury, which shews, that some part of the cantharides is absorbed; there is reason to conclude, that a part of the matter of small-pox is absorbed, and thus produces the secondary fever. See Class II. 1. 3. 9. And not simply by its stimulus on the surface of the ulcers beneath the scabs. The exsudation of a yellow fluid from beneath the confluent eruptions on the face before the height is spoken of in Class II. 1. 3. 2. The material thus absorbed in the secondary fever of small-pox differs from that of open ulcers, as it is only aerated through the elevated cuticle; and secondly, because there is not a constant supply of fresh matter, when that already in the pustules is exhausted, either by absorption, or by evaporation, or by its induration into a scab. Might not the covering the face assiduously and exactly with plasters, as with cerate of calamy, or with minium plaster, by precluding the air from the pustules, prevent their contracting a contagious, or acescent, or fever-producing power? and the secondary fever be thus prevented entirely. If the matter in those pustules on the face in the confluent small-pox were thus prevented from oxygenation, it is highly probable, both from this theory, and from the facts before mentioned, that the matter would not erode the skin beneath them, and by these means no marks or scars would succeed. 13. _Febris carcinomatosa._ Fever from the matter of cancer. In a late publication the pain is said to be relieved, and the fever cured, and the cancer eradicated, by the application of carbonic acid gas, or fixed air. See Class II. 1. 4. 16. 14. _Febris venerea._ From the absorption of the matter from venereal ulcers and suppurating bones. See Syphilis, II. 1. 5. 2. M. M. Any mercurial calx. Sarsaparilla? Mezereon? 15. _Febris a sanie putrida._ Fever from putrid sanies. When parts of the body are destroyed by external violence, as a bruise, or by mortification, a putrefaction soon succeeds; as they are kept in that degree of warmth and moisture by their adhesion to the living parts of the body, which most forwards that process. Thus the sloughs of mortified parts of the tonsils give fetor to the breath in some fevers; the matter from putrefying teeth, or other suppurating bones, is particularly offensive; and even the scurf, which adheres to the tongue, frequently acquires a bitter taste from its incipient putridity. This material differs from those before mentioned, as its deleterious property depends on a chemical rather than an animal process. 16. _Febris puerpera._ Puerperal fever. It appears from some late dissections, which have been published, of those women who have died of the puerperal fever, that matter has been formed in the omentum, and found in the cavity of the abdomen, with some blood or sanies. These parts are supposed to have been injured by the exertions accompanying labour; and as matter in this viscus may have been produced without much pain, this disease is not attended with arterial strength and hard full pulse like the inflammation of the uterus; and as the fever is of the inirritative or typhus kind, there is reason to believe, that the previous exhaustion of the patient during labour may contribute to its production; as well as the absorption of a material not purulent but putrid; which is formed by the delay of extravasated or dead matter produced by the bruises of the omentum, or other viscera, in the efforts of parturition, rather than by purulent matter, the consequence of suppuration. The pulse is generally about 120 when in bed and in the morning; and is increased to 134, or more, when the patient sits up, or in the evening paroxysm. The pulse of all very weak patients increases in frequency when they sit up; because the expenditure of sensorial power necessary to preserve an erect posture deducts so much from their general strength; and hence the pulse becomes weaker, and in consequence quicker. See Sect. XII. 1. 4. In this fever time must be allowed for the absorption of the matter. Very large and repeated quantities of the bark, by preventing sufficient food from being taken, as bread, and wine, and water, I have thought has much injured the patient; for the bark is not here given as in intermittent fevers to prevent the paroxysm, but simply to strengthen the patient by increasing the power of digestion. About two ounces of decoction of bark, with four drops of laudanum, and a dram of sweet spirit of vitriol, once in six hours, and a glass of wine between those times, with panada, or other food, I have thought of most advantage, with a small blister occasionally. Where not only the stomach but also the bowels are much distended with air, so as to sound on striking them with the fingers, the case is always dangerous, generally hopeless; which is more so in proportion to the quickness of the pulse. Where the bowels are distended two drops of oil of cinnamon should be given in the panada three or four times a day. 17. _Febris a sphacelo._ Fever from mortification. This fever from absorption of putrid matter is of the inirritative or typhus kind. See the preceding article. M. M. Opium and the bark are frequently given in too great quantity, so as to induce consequent debility, and to oppress the power of digestion. * * * * * ORDO I. _Increased Sensation._ GENUS VII. _With increased Action of the Organs of Sense._ SPECIES. 1. _Delirium febrile._ Paraphrosyne. The ideas in delirium consist of those excited by the sensation of pleasure or pain, which precedes them, and the trains of other ideas associated with these, and not of those excited by external irritations or by voluntary exertion. Hence the patients do not know the room which they inhabit, or the people who surround them; nor have they any voluntary exertion, where the delirium is complete; so that their efforts in walking about a room or rising from their bed are unsteady, and produced by their catenations with the immediate affections of pleasure or pain. See Section XXXIII. 1. 4. By the above circumstances it is distinguished from madness, in which the patients well know the persons of their acquaintance, and the place where they are; and perform all the voluntary actions with steadiness and determination. See Sect. XXXIV. 2. 2. Delirium is sometimes less complete, and then a new face and louder voice stimulate the patient to attend to them for a few moments; and then they relapse again into perfect delirium. At other times a delirium affects but one sense, and the person thinks he sees things which do not exist; and is at the same time sensible to the questions which are asked him, and to the taste of the food which is offered to him. This partial delirium is termed an hallucination of the disordered organ; and may probably arise from the origin of one nerve of sense being more liable to inflammation than the others; that is, an exuberance of the sensorial power of sensation may affect it; which is therefore thrown into action by slighter sensitive catenations, without being obedient to external stimulus, or to the power of volition. The perpetual flow of ideas in delirium is owing to the same circumstance, as of those in our dreams; namely, to the defect or paralysis of the voluntary power; as in hemiplagia, when one side of the body is paralytic, and thus expends less of the sensorial power, the limbs on the other side are in constant motion from the exuberance of it. Whence less sensorial power is exhausted in delirium, than at other times, as well as in sleep; and hence in fevers with great debility, it is perhaps, as well as the stupor, rather a favourable circumstance; and when removed by numerous blisters, the death of the patient often follows the recovery of his understanding. See Class I. 2. 5. 6. and I. 2. 5. 10. Delirium in diseases from inirritability is sometimes preceded by a propensity to surprise. See Class I. 1. 5. 11. M. M. Fomentations of the shaved head for an hour repeatedly. A blister on the head. Rising from bed. Wine and opium, and sometimes venesection in small quantity by cupping, if the strength of the arterial system will allow it. 2. _Delirium maniacale._ Maniacal delirium. There is another kind of delirium, described in Sect. XXXIII. 1. 4. which has the increase of pleasureable or painful sensation for its cause, without any diminution of the other sensorial powers; but as this excites the patient to the exertion of voluntary actions, for the purpose of obtaining the object of his pleasureable ideas, or avoiding the object of his painful ones, such as perpetual prayer, when it is of the religious kind, it belongs to the insanities described in Class III. 1. 2. 1, and is more properly termed hallucinatio maniacalis. 3. _Dilirium ebrietatis._ The drunken delirium is in nothing different from the delirium attending fevers except in its cause, as from alcohol, or other poisons. When it is attended with an apoplectic stupor, the pulse is generally low; and venesection I believe sometimes destroys those, who would otherwise have recovered in a few hours. M. M. Diluting liquids. An emetic. 4. _Somnium._ Dreams constitute the most complete kind of delirium. As in these no external irritations are attended to, and the power of volition is entirely suspended; so that the sensations of pleasure and pain, with their associations, alone excite the endless trains of our sleeping ideas; as explained in Sect. XVIII. on Sleep. 5. _Hallucinatio visûs._ Deception of sight. These visual hallucinations are perpetual in our dreams; and sometimes precede general delirium in fevers; and sometimes belong to reverie, and to insanity. See Class III. 1. 2. 1. and 2. and must be treated accordingly. Other kinds of visual hallucinations occur by moon-light; when objects are not seen so distinctly as to produce the usual ideas associated with them, but appear to us exactly as they are seen. Thus the trunk of a tree appears a flat surface, instead of a cylinder as by day, and we are deceived and alarmed by seeing things as they really are seen. See Berkley on Vision. 6. _Hallucinatio auditûs._ Auricular deception frequently occurs in dreams, and sometimes precedes general delirium in fevers; and sometimes belongs to vertigo, and to reverie, and to insanity. See Sect. XX. 7. and Class III. 1. 2. 1. and 2. 7. _Rubor a calore._ The blush from heat is occasioned by the increased action of the cutaneous vessels in consequence of the increased sensation of heat. See Class I. 1. 2. 1. and 3. 8. _Rubor jucunditatis._ The blush of joy is owing to the increased action of the capillary arteries, along with that of every moving vessel in the body, from the increase of pleasurable sensation. 9. _Priapismus amatorius._ Amatorial priapism. The blood is poured into the cells of the corpora cavernosa much faster than it can be reabsorbed by the vena penis, owing in this case to the pleasurable sensation of love increasing the arterial action. See Class I. 1. 4. 6. 10. _Distentio mamularum._ The teats of female animals, when they give suck, become rigid and erected, in the same manner as in the last article, from the pleasurable sensation of the love of the mother to her offspring. Whence the teat may properly be called an organ of sense. The nipples of men do the same when rubbed with the hand. See Class I. 1. 4. 7. * * * * * ORDO II. _Decreased Sensation._ GENUS I. _Of the General System._ SPECIES. 1. _Stultitia insensibilis._ Folly from insensibility. The pleasure or pain generated in the system is not sufficient to promote the usual activity either of the sensual or muscular fibres. 2. _Tædium vitæ._ Ennui. Irksomeness of life. The pain of laziness has been thought by some philosophers to be that principle of action, which has excited all our industry, and distinguished mankind from the brutes of the field. It is certain that, where the ennui exists, it is relieved by the exertions of our minds or bodies, as all other painful sensations are relieved; but it depends much upon our early habits, whether we become patient of laziness, or inclined to activity, during the remainder of our lives, as other animals do not appear to be affected with this malady; which is perhaps left owing to deficiency of pleasurable sensation, than to the superabundancy of voluntary power, which occasions pain in the muscles by its accumulation; as appears from the perpetual motions of a squirrel confined in a cage. 3. _Paresis sensitiva._ Weakness of the whole system from insensibility. * * * * * ORDO II. _Decreased Sensation._ GENUS II. _Of Particular Organs._ SPECIES. 1. _Anorexia._ Want of appetite. Some elderly people, and those debilitated by fermented liquors, are liable to lose their appetite for animal food; which is probably in part owing to the deficiency of gastric acid, as well as to the general decay of the system: elderly people will go on years without animal food; but inebriates soon sink, when their digestion becomes so far impaired. Want of appetite is sometimes produced by the putrid matter from many decaying teeth being perpetually mixed with the saliva, and thence affecting the organ of taste, and greatly injuring the digestion. M. M. Fine charcoal powder diffused in warm water held in the mouth frequently in a day, as in Class I. 2. 4. 12. or solution of alum in water. Extract the decayed teeth. An emetic. A blister. Chalybeates. Vitriolic acid. Bile of an ox inspissated, and made into pills; 20 grains to be taken before dinner and supper. Opium half a grain twice a day. All the strength we possess is ultimately derived from the food, which we are able to digest; whence a total debility of the system frequently follows the want of appetite, and of the power of digestion. Some young ladies I have observed to fall into this general debility, so as but just to be able to walk about; which I have sometimes ascribed to their voluntary fasting, when they believed themselves too plump; and who have thus lost both their health and beauty by too great abstinence, which could never be restored. I have seen other cases of what may be termed anorexia epileptica, in which a total loss of appetite, and of the power of digestion, suddenly occurred along with epileptic fits. Miss B. a girl about eighteen, apparently very healthy, and rather plump, was seized with fits, which were at first called hysterical; they occurred at the end of menstruation, and returned very frequently with total loss of appetite. She was relieved by venesection, blisters, and opiates; her strength diminished, and after some returns of the fits, she took to her bed, and has survived 15 or 20 years; she has in general eaten half a potato a day, and seldom speaks, but retains her senses, and had many years occasional returns of convulsion. I have seen two similar cases, where the anorexia, or want of appetite, was in less degree; and but just so much food could be digested, as supplied them with sufficient strength to keep from the bed or sofa for half the day. As well as I can recollect, all these patients were attended with weak pulse, and cold pale skin; and received benefit by opium, from a quarter of a grain to a grain four times a day. See Class III. 1. 1. 7. and III. 1. 2. 1. and III. 1. 2. 20. 2. _Adipsia._ Want of thirst. Several of the inferior people, as farmers wives, have a habit of not drinking with their dinner at all, or only take a spoonful or two of ale after it. I have frequently observed these to labour under bad digestion, and debility in consequence; which I have ascribed to the too great stimulus of solid food undiluted, destroying in process of time the irritability of the stomach. 3. _Impotentia_ (agenesia). Impotency much seldomer happens to the male sex than sterility to the female sex. Sometimes a temporary impotence occurs from bashfulness, or the interference of some voluntary exertion in the production of an effect, which should be performed alone by pleasurable sensation. One, who was soon to be married to a lady of superior condition to his own, expressed fear of not succeeding on the wedding night; he was advised to take a grain of opium before he went to bed, and to accustom himself to sleep with a woman previously, but not to enjoy her, to take off his bashfulness; which succeeded to his wish. M. M. Chalybeates. Opium. Bark. Tincture of cantharides. 4. _Sterilitas._ Barrenness. One of the ancient medical writers asserts, that the female sex become pregnant with most certainty at or near the time of menstruation. This is not improbable, since these monthly periods seem to referable the monthly venereal orgasm of some female quadrupeds, which become pregnant at those times only; and hence the computation of pregnancy is not often erroneous, though taken from the last menstruation. See Section XXXVI. 2. 3. M. M. Opium a grain every night. Chalybeates in very small doses. Bark. Sea-bathing. 5. _Insensibilitas artuum._ As in some paralytic limbs. A great insensibility sometimes accompanies the torpor of the skin in cold fits of agues. Some parts have retained the sense of heat, but not the sense of touch. See Sect. XVI. 6. M. M. Friction with flannel. A blister. Warmth. 6. _Dysuria insensitiva._ Insensibility of the bladder. A difficulty or total inability to make water attends some fevers with great debility, owing to the insensibility or inirritability of the bladder. This is a dangerous but not always a fatal symptom. M. M. Draw off the water with a catheter. Assist the patient in the exclusion of it by compressing the lower parts of the abdomen with the hands. Wine two ounces, Peruvian bark one dram in decoction, every three hours alternately. Balsam of copaiva. Oil of almonds, with as much camphor as can be dissolved in it, applied as a liniment rubbed on the region of the bladder and perinæum, and repeated every four hours, was used in this disease with success by Mr. Latham. Med. Comment. 1791, p. 213. 7. _Accumulatio alvina._ An accumulation of feces in the rectum, occasioned by the torpor, or insensibility, of that bowel. But as liquids pass by these accumulations, it differs from the constipatio alvi, which is owing to too great absorption of the alimentary canal. Old milk, and especially when boiled, is liable to induce this kind of costiveness in some grown persons; which is probably owing to their not possessing sufficient gastric acid to curdle and digest it; for as both these processes require gastric acid, it follows, that a greater quantity of it is necessary, than in the digestion of other aliments, which do not previously require being curdled. This ill digested milk not sufficiently stimulating the rectum, remains till it becomes a too solid mass. On this account milk seldom agrees with those, who are subject to piles, by inducing costiveness and large stools. M. M. Extract the hardened scybala by means of a marrow-spoon; or by a piece of wire, or of whale-bone bent into a bow, and introduced. Injections of oil. Castor oil, or oil of almonds, taken by the mouth. A large clyster of smoak of tobacco. Six grains of rhubarb taken every night for many months. Aloes. An endeavour to establish a habit of evacuation at a certain hour daily. See Class I. 1. 3. 5. * * * * * ORDO III. _Retrograde Sensitive Motions._ GENUS I. _Of Excretory Ducts._ The retrograde action of the oesophagus in ruminating animals, when they bring up the food from their first stomach for the purpose of a second mastication of it, may probably be caused by agreeable sensation; similar to that which induces them to swallow it both before and after this second mastication; and then this retrograde action, properly belongs to this place, and is erroneously put at the head of the order of irritative retrograde motions. Class I. 3. 1. 1. SPECIES. 1. _Ureterum motus retrogressus._ When a stone has advanced into the ureter from the pelvis of the kidney, it is sometimes liable to be returned by the retrograde motion of that canal, and the patient obtains fallacious ease, till the stone is again pushed into the ureter. 2. _Urethræ motus retrogressus._ There have been instances of bougies being carried up the urethra into the bladder most probably by an inverted motion of this canal; for which some have undergone an operation similar to that for the extraction of a stone. A case is related in some medical publication, in which a catgut bougie was carried into the bladder, and after remaining many weeks, was voided piece-meal in a semi-dissolved state. Another case is related of a French officer, who used a leaden bougie; which at length found its way into the bladder, and was, by injecting crude mercury, amalgamated and voided. In the same manner the infection from a simple gonorrhoea is probably carried further along the course of the urethra; and small stones frequently descend some way into the urethra, and are again carried up into the bladder by the inverted action of this canal. 3. _Ductus choledochi motus retrogressus._ The concretions of bile, called gall-stones, frequently enter the bile-duct, and give violent pain for some hours; and return again into the gall-bladder, by the retrograde action of this duct. May not oil be carried up this duct, when a gall-stone gives great pain, by its retrograde spasmodic action? See Class I. 1. 3. 8. M. M. Opium a grain and half. * * * * * _The Orders and Genera of the Third Class of Diseases._ * * * * * CLASS III. DISEASES OF VOLITION. ORDO I. _Increased Volition._ GENERA. 1. With increased actions of the muscles. 2. With increased actions of the organs of sense. ORDO II. _Decreased Volition._ GENERA. 1. With decreased actions of the muscles. 2. With decreased actions of the organs of sense. * * * * * _The Orders, Genera, and Species, of the Third Class of Diseases._ * * * * * CLASS III. DISEASES OF VOLITION. ORDO I. _Increased Volition._ GENUS I. _With Increased Actions of the Muscles._ SPECIES. 1. _Jactitatio._ Restlessness. 2. _Tremor febrilis._ Febrile trembling. 3. _Clamor._ Screaming. 4. _Risus._ Laughter. 5. _Convulsio._ Convulsion. ---- _debilis._ ---- weak. 6. ---- _dolorifica._ ---- painful. 7. _Epilepsia._ Epilepsy. 8. ---- _dolorifica._ ---- painful. 9. _Somnambulismus._ Sleep-walking. 10. _Asthma convulsivum._ Asthma convulsive. 11. ---- _dolorificum._ ---- painful. 12. _Stridor dentium._ Gnashing of the teeth. 13. _Tetanus trismus._ Cramp of the jaw. 14. ---- _dolorificus._ ---- painful. 15. _Hydrophobia._ Dread of water. GENUS II. _With increased Actions of the Organs of Sense._ SPECIES. 1. _Mania mutabilis._ Mutable madness. 2. _Studium inane._ Reverie. 3. _Vigilia._ Watchfulness. 4. _Erotomania._ Sentimental love. 5. _Amor sui._ Vanity. 6. _Nostalgia._ Desire of home. 7. _Spes religiosa._ Superstitious hope. 8. _Superbia stemmatis._ Pride of family. 9. _Ambitio._ Ambition. 10. _Mæror._ Grief. 11. _Tædium vitæ._ Irksomeness of life. 12. _Desiderium pulchritudinis._ Loss of beauty. 13. _Paupertatis timor._ Fear of poverty. 14. _Lethi timor._ ---- of death. 15. _Orci timor._ ---- of hell. 16. _Satyriasis._ Lust. 17. _Ira._ Anger. 18. _Rabies._ Rage. 19. _Citta._ Depraved appetite. 20. _Cacositia._ Aversion to food. 21. _Syphilis imaginaria._ Imaginary pox. 22. _Psora imaginaria._ ---- itch. 23. _Tabes imaginaria._ ---- tabes. 24. _Sympathia aliena._ Pity. 25. _Educatio heroica._ Heroic education. ORDO II. _Decreased Volition._ GENUS I. _With decreased Actions of the Muscles._ SPECIES. 1. _Lassitudo._ Fatigue. 2. _Vacillatio senilis._ See-saw of old age. 3. _Tremor senilis._ Tremor of old age. 4. _Brachiorum paralysis._ Palsy of the arms. 5. _Raucedo paralytica._ Paralytic hoarseness. 6. _Vesicæ urinariæ paralysis._ Palsy of the bladder. 7. _Recti paralysis._ Palsy of the rectum. 8. _Paresis voluntaria._ Voluntary debility. 9. _Catalepsis._ Catalepsy. 10. _Hemiplegia._ Palsy of one side. 11. _Paraplegia._ Palsy of the lower limbs. 12. _Somnus._ Sleep. 13. _Incubus._ Night-mare. 14. _Lethargus._ Lethargy. 15. _Syncope epileptica._ Epileptic fainting. 16. _Apoplexia._ Apoplexy. 17. _Mors a frigore._ Death from cold. GENUS II. _With decreased Actions of the Organs of Sense._ SPECIES. 1. _Recollectionis jactura._ Loss of recollection. 2. _Stultitia voluntaria._ Voluntary folly. 3. _Credulitas._ Credulity. * * * * * CLASS III. DISEASES OF VOLITION. ORDO I. _Increased Volition._ GENUS I. _Increased Actions of the Muscles._ We now step forward to consider the diseases of volition, that superior faculty of the sensorium, which gives us the power of reason, and by its facility of action distinguishes mankind from brute animals; which has effected all that is great in the world, and superimposed the works of art on the situations of nature. Pain is introduced into the system either by excess or defect of the action of the part. (Sect. IV. 5.) Both which circumstances seem to originate from the accumulation of sensorial power in the affected organ. Thus when the skin is exposed to great cold, the activity of the cutaneous vessels is diminished, and in consequence an accumulation of sensorial power obtains in them, because they are usually excited into incessant motion by the stimulus of heat, as explained in Sect. XII. 5. 2. Contrarywise, when the vessels of the skin are exposed to great heat, an excess of sensorial power is also produced in them, which is derived thither by the increase of stimulus above what is natural. This accounts for the relief which is received in all kinds of pain by any violent exertions of our muscles or organs of sense; which may thus be in part ascribed to the exhaustion of the sensorial power by such exertions. But this relief is in many cases so instantaneous, that it seems nevertheless probable, that it is also in part owing to the different manner of progression of the two sensorial powers of sensation and volition; one of them commencing at some extremity of the sensorium, and being propagated towards the central parts of it; and the other commencing in the central parts of the sensorium, and being propagated towards the extremities of it; as mentioned in Sect. XI. 2. 1. These violent voluntary exertions of our muscles or ideas to relieve the sensation of pain constitute convulsions and madness; and are distinguished from the muscular actions owing to increased sensation, as in sneezing, or coughing, or parturition, or ejectio feminis, because they do not contribute to dislodge the cause, but only to prevent the sensation of it. In two cases of parturition, both of young women with their first child, I have seen general convulsions occur from excess of voluntary exertion, as above described, instead of the actions of particular muscles, which ought to have been excited by sensation for the exclusion of the fetus. They both became insensible, and died after some hours; from one of them the fetus was extracted in vain. I have heard also of general convulsions being excited instead of the actions of the musculi acceleratores in the ejectio feminis, which terminated fatally. See Class III. 1. 1. 7. These violent exertions are most frequently excited in consequence of those pains, which originate from defect of the action of the part. See Sect. XXXIV. 1. and 2. The pains from excess and defect of the action of the part are distinguishable from each other by the former being attended with increase of heat in the pained part, or of the whole body; while the latter not only exist without increase of heat in the pained part, but are generally attended with coldness of the extremities of the body. As soon as these violent actions of our muscular or sensual fibres for the purpose of relieving pain cease to be exerted, the pain recurs; whence the reciprocal contraction and relaxation of the muscles in convulsion, and the intervals of madness. Otherwise these violent exertions continue, till so great a part of the sensorial power is exhausted, that no more of it is excitable by the faculty of volition; and a temporary apoplexy succeeds, with snoring as in profound sleep; which so generally terminates epileptic fits. When these voluntary exertions become so connected with certain disagreeable sensations, or with irritations, that the effort of the will cannot restrain them, they can no longer in common language be termed voluntary; but nevertheless belong to this class, as they are produced by excess of volition, and may still not improperly be called depraved voluntary actions. See Sect. XXXIV. 1. where many motions in common language termed involuntary are shewn to depend on excess of volition. When these exertions from excess of volition, which in common language are termed involuntary motions, either of mind or body, are perpetually exerted in weak constitutions, the pulse becomes quick; which is occasioned by the too great expenditure of the sensorial power in these unceasing modes of activity. In the same manner as in very weak people in fevers, the pulse sometimes increases in frequency to 140 strokes in a minute, when the patients stand up or endeavour to walk; and subsides to 110, when they lie down again in their beds. Whence it appears, that when a very quick pulse accompanies convulsion or insanity, it simply indicates the weakness of the patient; that is, that the expenditure of sensorial power is too great for the supply of it. But if the strength of the patient is not previously exhausted, the exertions of the muscles are attended with temporary increase of circulation, the reciprocal swellings and elongations of their bellies push forwards the arterial blood, and promote the absorption of the venous blood; whence a temporary increase of secretion and of heat, and a stronger pulse. SPECIES. 1. _Jactitatio._ Restlessness. There is one kind of restlessness attending fevers, which consists in a frequent change of posture to relieve the uneasiness of the pressure of one part of the body upon another, when the sensibility of the system, or of some parts of it, is increased by inflammation, as in the lumbago; which may sometimes be distinguished in its early stage by the incessant desire of the patient to turn himself in bed. But there is another restlessness, which approaches towards writhing or contortions of the body, which is a voluntary effort to relieve pain; and may be esteemed a slighter kind of convulsion, not totally unrestrainable by opposite or counteracting volitions. M. M. A blister. Opium. Warm bath. 2. _Tremor febrilis._ Reciprocal convulsions of the subcutaneous muscles, originating from the pain of the sense of heat, owing to defect of its usual stimulus, and consequent accumulation of sensorial power in it. The actual deficiency of heat may exist in one part of the body, and the pain of cold be felt most vividly in some other part associated with it by sensitive sympathy. So a chillness down the back is first attended to in ague-fits, though the disease perhaps commences with the torpor and consequent coldness of some internal viscus. But in whatever part of the system the defect of heat exists, or the sensation of it, the convulsions of the subcutaneous muscles exerted to relieve it are very general; and, if the pain is still greater, a chattering of the teeth is added, the more suddenly to exhaust the sensorial power, and because the teeth are very sensible to cold. These convulsive motions are nevertheless restrainable by violent voluntary counteraction; and as their intervals are owing to the pain of cold being for a time relieved by their exertion, they may be compared to laughter, except that there is no interval of pleasure preceding each moment of pain in this as in the latter. M. M. See I. 2. 2. 1. 3. _Clamor._ Screaming from pain. The talkative animals, as dogs, and swine, and children, scream most, when they are in pain, and even from fear; as they have used this kind of exertion from their birth most frequently and most forcibly; and can therefore sooner exhaust the accumulation of sensorial power in the affected muscular or sensual organs by this mode of exertion; as described in Sect. XXXIV. 1. 3. This facility of relieving pain by screaming is the source of laughter, as explained below. 4. _Risus._ The pleasurable sensations, which occasion laughter, are perpetually passing into the bounds of pain; for pleasure and pain are often produced by different degrees of the same stimulus; as warmth, light, aromatic or volatile odours, become painful by their excess; and the tickling on the soles of the feet in children is a painful sensation at the very time it produces laughter. When the pleasurable ideas, which excite us to laugh, pass into pain, we use some exertion, as a scream, to relieve the pain, but soon stop it again, as we are unwilling to lose the pleasure; and thus we repeatedly begin to scream, and stop again alternately. So that in laughing there are three stages, first of pleasure, then pain, then an exertion to relieve that pain. See Sect. XXXIV. 1. 3. Every one has been in a situation, where some ludicrous circumstance has excited him to laugh; and at the same time a sense of decorum has forbid the exertion of these interrupted screams; and then the pain has become so violent, as to occasion him to use some other great action, as biting his tongue, and pinching himself, in lieu of the reiterated screams which constitute laughter. 5. _Convulsio._ Convulsion. When the pains from defect or excess of motion are more distressing than those already described, and are not relievable by such partial exertions, as in screaming, or laughter, more general convulsions occur; which vary perhaps according to the situation of the pained part, or to some previous associations formed by the early habits of life. When these convulsive motions bend the body forwards, they are termed emprosthotonoi; when they bend it backward, they are termed opisthotonoi. They frequently succeed each other, but the opisthotonoi are generally more violent; as the muscles, which erect the body, and keep it erect, are naturally in more constant and more forcible action than their antagonists. The causes of convulsion are very numerous, as from toothing in children, from worms or acidity in their bowels, from eruption of the distinct small-pox, and lastly, from breathing too long the air of an unventilated bed-room. Sir G. Baker, in the Transactions of the College, described this disease, and detected its cause; where many children in an orphan-house were crowded together in one chamber without a chimney, and were almost all of them affected with convulsion; in the hospital at Dublin, many died of convulsions before the real cause was understood. See Dr. Beddoes's Guide to Self-preservation. In a large family, which I attended, where many female servants slept in one room, which they had contrived to render inaccessible to every blast of air; I saw four who were thus seized with convulsions, and who were believed to have been affected by sympathy from the first who fell ill. They were removed into more airy apartments, but were some weeks before they all regained their perfect health. Convulsion is distinguished from epilepsy, as the patient does not intirely lose all perception during the paroxysm. Which only shews, that a less exhaustion of sensorial power renders tolerable the pains which cause convulsion, than those which cause epilepsy. The hysteric convulsions are distinguished from those, owing to other causes, by the presence of the expectation of death, which precedes and succeeds them, and generally by a flow of pale urine; these convulsions do not constantly attend the hysteric disease, but are occasionally superinduced by the disagreeable sensation arising from the torpor or inversion of a part of the alimentary canal. Whence the convulsion of laughter is frequently sufficient to restrain these hysteric pains, which accounts for the fits of laughter frequently attendant on this disease. M. M. To remove the peculiar pain which excites the convulsions. Venesection. An emetic. A cathartic with calomel. Warm-bath. Opium in large quantities, beginning with smaller ones. Mercurial frictions. Electricity. Cold-bath in the paroxysm; or cold aspersion. See Memoirs of Med. Society, Lon. V. 3. p. 147. a paper by Dr. Currie. _Convulsio debilis._ The convulsions of dying animals, as of those which are bleeding to death in the slaughter-house, are an effort to relieve painful sensation, either of the wound which occasions their death, or of faintness from want of due distention of the blood-vessels. Similar to this in a less degree is the subsultus tendinum, or starting of the tendons, in fevers with debility; these actions of the muscles are too weak to move the limb, but the belly of the acting muscles is seen to swell, and the tendon to be stretched. These weak convulsions, as they are occasioned by the disagreeable sensation of faintness from inanition, are symptoms of great general debility, and thence frequently precede the general convulsions of the act of dying. See a case of convulsion of a muscle of the arm, and of the fore-arm, without moving the bones to which they were attached, Sect. XVII. 1. 8. See twitchings of the face, Class IV. 1. 3. 2. 6. _Convulsio dolorifica._ Raphania. Painful convulsion. In this disease the muscles of the arms and legs are exerted to relieve the pains left after the rheumatism in young and delicate people; it recurs once or twice a-day, and has been mistaken for the chorea, or St. Vitus's dance; but differs from it, as the undue motions in that disease only occur, when the patient endeavours to exert the natural ones; are not attended with pain; and cease, when he lies down without trying to move: the chorea, or dance of St. Vitus, is often introduced by the itch, this by the rheumatism. It has also been improperly called nervous rheumatism; but is distinguished from rheumatism, as the pains recur by periods once or twice a day; whereas in the chronic rheumatism they only occur on moving the affected muscles. And by the warmth of a bed the pains of the chronic rheumatism are increased, as the muscles or membranes then become more sensible to the stimulus of the extraneous mucaginous material deposited under them. Whereas the pains of the raphania, or painful convulsion, commence with coldness of the part, or of the extremities. See Rheumatismus chronicus, Class I. 1. 3. 12. The pains which accompany the contractions of the muscles in this disease, seem to arise from the too great violence of those contractions, as happens in the cramp of the calf of the leg; from which they differ in those being fixed, and these being reiterated contractions. Thus these convulsions are generally of the lower limbs, and recur at periodical times from some uneasy sensation from defect of action, like other periodic diseases; and the convulsions of the limbs relieve the original uneasy painful sensation, and then produce a greater pain from their own too vehement contractions. There is however another way of accounting for these pains, when they succeed the acute rheumatism; and that is by the coagulable lymph, which may be left still unabsorbed on the membranes; and which may be in too small quantity to affect them with pain in common muscular exertions, but may produce great pain, when the bellies of the muscles swell to a larger bulk in violent action. M. M. Venesection. Calomel. Opium. Bark. One grain of calomel and one of opium for ten successive nights. A bandage spread with emplastrum de minio put tight on the affected part. 7. _Epilepsia_ is originally induced, like other convulsions, by a voluntary exertion to relieve some pain. This pain is most frequently about the pit of the stomach, or termination of the bile-duct; and in some cases the torpor of the stomach, which probably occasioned the epileptic fits, remains afterwards, and produces a chronical anorexia; of which a case is related in Class II. 2. 2. 1. There are instances of its beginning in the heel, of which a case is published by Dr. Short, in the Med. Essays, Edinb. I once saw a child about ten years old, who frequently fell down in convulsions, as she was running about in play; on examination a wart was found on one ancle, which was ragged and inflamed; which was directed to be cut off, and the fits never recurred. When epilepsy first commences, the patients are liable to utter one scream before they fall down; afterwards the convulsions so immediately follow the pain, which occasions them, that the patient does not recollect or seem sensible of the preceding pain. Thus in laughter, when it is not excessive, a person is not conscious of the pain, which so often recurs, and causes the successive screams or exertions of laughter, which give a temporary relief to it. Epileptic fits frequently recur in sleep from the increase of sensibility at that time, explained in Sect. XVIII. 14. In two such cases, both of young women, one grain of opium given at night, and continued many months, had success; in one of them the opium was omitted twice at different times, and the fit recurred on both the nights. In the more violent case, described in Sect. XVIII. 15, opium had no effect. Epileptic fits generally commence with setting the teeth, by which means the tongue is frequently wounded; and with rolling the eyeballs in every kind of direction; for the muscles which suspend the jaw, as well as those which move the eyes, are in perpetual motion during our waking hours; and yet continue subservient to volition; hence their more facile and forcible actions for the purpose of relieving pain by the exhaustion of sensorial power. See Section XXXIV. 1. 4. Epileptic convulsions are not attended with the fear of death, as in the hysteric disease, and the urine is of a straw colour. However it must be noted, that the disagreeable sensations in hysteric diseases sometimes are the cause of true epileptic convulsions, of syncope, and of madness. The pain, which occasions some fits of epilepsy, is felt for a time in a distant part of the system, as in a toe or heel; and is said by the patient gradually to ascend to the head, before the general convulsions commence. This ascending sensation has been called aura epileptica, and is said to have been prevented from affecting the head by a tight bandage round the limb. In this malady the pain, probably of some torpid membrane, or diseased tendon, is at first only so great as to induce slight spasms of the muscular fibres in its vicinity; which slight spasms cease on the numbness introduced by a tight bandage; when no bandage is applied, the pain gradually increases, till generally convulsions are exerted to relieve it. The course of a lymphatic, as when poisonous matter is absorbed; or of a nerve, as in the sciatica, may, by the sympathy existing between their extremities and origins, give an idea of the ascent of an aura or vapour. In difficult parturition it sometimes happens, that general convulsions are excited to relieve the pain of labour, instead of the exertions of those muscles of the abdomen and diaphragm, which ought to forward the exclusion of the child. See Class III. 1. 1. That is, instead of the particular muscular actions, which ought to be excited by sensation to remove the offending cause, general convulsions are produced by the power of volition, which still the pain, as in common epilepsy, without removing the cause; and, as the parturition is not thus promoted, the convulsions continue, till the sensorial power is totally exhausted, that is, till death. In patients afflicted with epilepsy from other causes, I have seen the most violent convulsions recur frequently during pregnancy without miscarriage, as they did not tend to forward the exclusion of the fetus. M. M. Venesection. A large dose of opium. Delivery. The later in life epileptic fits are first experienced, the more dangerous they may be esteemed in general; as in these cases the cause has generally been acquired by the habits of the patient, or by the decay of some part, and is thus probably in an increasing state. Whereas in children the changes in the system, as they advance to puberty, sometimes removes the cause. So in toothing, fits of convulsion with stupor frequently occur, and cease when the tooth advances; but this is not to be expected in advanced life. Sir ----, about sixty years of age, had only three teeth left in his upper jaw, a canine tooth, and one on each side of it. He was seized with epileptic fits, with pain commencing in these teeth. He was urged to have them extracted, which he delayed too long, till the fits were become habitual, and then had them extracted in vain, and in a few months sunk under the disease. Mr. F----, who had lived intemperately, and had been occasionally affected with the gout, was suddenly seized with epileptic fits; the convulsions were succeeded by apoplectic snoring; from which he was, in about 20 minutes, disturbed by fresh convulsions, and had continued in this situation above four-and-twenty hours. About eight ounces of blood were then taken from him; and after having observed, that the apoplectic's torpor continued about 20 minutes, I directed him to be forcibly raised up in bed, after he had thus lain about fifteen minutes, to gain an interval between the termination of the sleep, and the renovation of convulsion. In this interval he was induced to swallow forty drops of laudanum. Twenty more were given him in the same manner in about half an hour, both which evidently shortened the convulsion fits, and the consequent stupor; he then took thirty more drops, which for the present removed the fits. He became rather insane the next day, and after about three more days lost the insanity, and recovered his usual state of health. The case mentioned in Sect. XXVII. 2. where the patient was left after epileptic fits with a suffusion of blood beneath the tunica adjunctiva of the eye, was in almost every respect similar to the preceding, and submitted to the same treatment. Both of them suffered frequent relapses, which were relieved by the same means, and at length perished, I believe, by the epileptic fits. In those patients, who have not been subject to epilepsy before they have arrived to about forty years of age, and who have been intemperate in respect to spirituous potation, I have been induced to believe, that the fits were occasioned by the pain of a diseased liver; and this became more probable in one of the above subjects, who had used means to repel eruptions on the face; and thus by some stimulant application had prevented an inflammation taking place on the skin of the face instead of on some part of the liver. Secondly, as in these cases insanity had repeatedly occurred, which could not be traced from an hereditary source; there is reason to believe, that this as well as the epileptic convulsions were caused by spirituous potation; and that this therefore is the original source both of epilepsy and of insanity in those families, which are afflicted with them. This idea however brings some consolation with it; as it may be inferred, that in a few sober generations these diseases may be eradicated, which otherwise destroy the family. M. M. Venesection. Opium. Bark. Steel. Arsenic. Opium one grain twice a day for years together. See the preceding article. 8. _Epilepsia dolorifica._ Painful epilepsy. In the common epilepsy the convulsions are immediately induced, as soon as the disagreeable sensation, which causes them, commences; but in this the pain continues long with cold extremities, gradually increasing for two or three hours, till at length convulsions or madness come on; which terminate the daily paroxysm, and cease themselves in a little time afterwards. This disease sometimes originates from a pain about the lower edge of the liver, sometimes in the temple, and sometimes in the pudendum; it recurs daily for five or six weeks, and then ceases for several months. The pain is owing to defect of action, that is, to the accumulation of sensorial power in the part, which probably sympathizes with some other part, as explained in Sect. XXXV. 2. XII. 5. 3. and Class II. 1. 1. 11. and IV. 2. 2. 3. It is the most painful malady that human nature is liable to!--See Sect. XXXIV. 1. 4. Mrs. C---- was seized every day about the same hour with violent pain on the right side of her bowels about the situation of the lower edge of the liver, without fever, which increased for an hour or two, till it became totally intolerable. After violent screaming she fell into convulsions, which terminated sometimes in fainting, with or without stertor, as in common epilepsy; at other times a tempory insanity supervened; which continued about half an hour, and the fit ceased. These paroxysms had returned daily for two or three weeks, and were at length removed by large doses of opium, like the fits of reverie or somnambulation. About half an hour before the expected return of the fit three or four grains of opium were exhibited, and then tincture of opium was given in warm brandy and water about 20 or 30 drops every half hour, till the eyes became somewhat inflamed, and the nose began to itch, and by the sharp movements of the patient, or quick speech, an evident intoxication appeared; and then it generally happened that the pain ceased. But the effects of this large dose of opium was succeeded by perpetual sickness and efforts to vomit, with great general debility all the succeeding day. The rationale of this temporary cure from the exhibition of opium and vinous spirit depends on the great expenditure of sensorial power in the increased actions of all the irritative motions, by the stimulus of such large quantities of opium and vinous spirit; together with the production of much sensation, and many movements of the organs of sense or ideas in consequence of that sensation; and lastly, even the motions of the arterial system become accelerated by this degree of intoxication, all which soon exhausted so much sensorial power as to relieve the pain; which would otherwise have caused convulsions or insanity, which are other means of expending sensorial power. The general debility on the succeeding day, and the particular debility of the stomach, attended in consequence with sickness and frequent efforts to vomit, were occasioned by the system having previously been so strongly stimulated, and those parts in particular on which the opium and wine more immediately acted. This sickness continued so many hours as to break the catenation of motions, which had daily reproduced the paroxysm; and thus it generally happened, that the whole disease ceased for some weeks or months from one great intoxication, a circumstance not easily to be explained on any other theory. The excess or defect of motion in any part of the system occasions the production of pain in that part, as in Sect. XII. 1. 6. This defect or excess of fibrous action is generally induced by excess or defect of the stimulus of objects external to the moving organ. But there is another source of excessive fibrous action, and consequent pain, which is from excess of volition, which is liable to affect those muscles, that have weak antagonists; as those which support the under jaw, and close the mouth in biting, and those of the calf of the leg; which are thus liable to fixed or painful contractions, as in trismus, or locked jaw, and in the cramp of the calf of the leg; and perhaps in some colics, as in that of Japan: these pains, from contraction arising from excess of volition in the part from the want of the counteraction of antagonist muscles, may give occasional cause to epileptic fits, and may be relieved in the same way, either by exciting irritative and sensitive motions by the stimulus of opium and wine; or by convulsions or insanity, as described above, which are only different methods of exhausting the general quantity of sensorial power. Considering the great resemblance between this kind of painful epilepsy and the colic of Japan, as described by Kemfer; and that that disease was said to be cured by acupuncture, or the prick of a needle; I directed some very thin steel needles to be made about three inches long, and of such a temper, that they would bend double rather than break; and wrapped wax thread over about half an inch of the blunt end for a handle. One of these needles, when the pain occurred, was pushed about an inch into the painful part, and the pain instantly ceased; but I was not certain, whether the fear of the patient, or the stimulus of the puncture, occasioned the cessation of pain; and as the paroxysm had continued some weeks, and was then declining, the experiment was not tried again. The disease is said to be very frequent in Japan, and its seat to be in the bowels, and that the acupuncture eliminates the air, which is supposed to distend the bowel. But though the aperture thus made is too small to admit of the eduction of air; yet as the stimulus of so small a puncture may either excite a torpid part into action, or cause a spasmodic one to cease to act; and lastly, as no injury could be likely to ensue from so small a perforation, I should be inclined at some future time to give this a fairer trial in similar circumstances. Another thing worth trial at the commencement of this deplorable disease would be electricity, by passing strong shocks through the painful part; which, whether the pain was owing to the inaction of that part, or of some other membrane associated with it, might stimulate them into exertion; or into inactivity, if owing to fixed painful contraction. And lastly, the cold bath, or aspersions with cold water on the affected part, according to the method of Dr. Currie in the Memoirs of a Med. Soc. London, V. iii. p. 147, might produce great effect at the commencement of the pain. Nevertheless opium duly administered, so as to precede the expected paroxysm, and in such doses, given by degrees, as to induce intoxication, is principally to be depended upon in this deplorable malady. To which should be added, that if venesection can be previously performed, even to but few ounces, the effect of the opium is much more certain; and still more so, if there be time to premise a brisk cathartic, or even an emetic. The effect of increased stimulus is so much greater after previous defect of stimulus; and this is still of greater advantage where the cause of the disease happens to consist in a material, which can be absorbed. See Art. IV. 2. 8. M. M. Venesection. An emetic. A cathartic. Warm bath. Opium a grain every half hour. Wine. Spirit of wine. If the patient becomes intoxicated by the above means, the fit ceases, and violent vomitings and debility succeed on the subsequent day, and prevent a return. Blisters or sinapisms on the small of the leg, taken off when they give much pain, are of use in slighter convulsions. Acupuncture. Electricity. Aspersion with cold water on the painful part. 9. _Somnambulismus._ Sleep-walking is a part of reverie, or studium inane, described in Sect. XIX. In this malady the patients have only the general appearance of being asleep in respect to their inattention to the stimulus of external objects, but, like the epilepsies above described, it consists in voluntary exertions to relieve pain. The muscles are subservient to the will, as appears by the patient's walking about, and sometimes doing the common offices of life. The ideas of the mind also are obedient to the will, because their discourse is consistent, though they answer imaginary questions. The irritative ideas of external objects continue in this malady, because the patients do not run against the furniture of the room; and when they apply their volition to their organs of sense, they become sensible of the objects they attend to, but not otherwise, as general sensation is destroyed by the violence of their voluntary exertions. At the same time the sensations of pleasure in consequence of ideas excited by volition are vividly experienced, and other ideas seem to be excited by these pleasurable sensations, as appears in the case of Master A. Sect. XXXIV. 3. 1. where a history of a hunting scene was voluntarily recalled, with all the pleasurable ideas which attended it. In melancholy madness the patient is employed in voluntarily exciting one idea, with those which are connected with it by voluntary associations only, but not so violently as to exclude the stimuli of external objects. In reverie variety of ideas are occasionally excited by volition, and those which are connected with them either by sensitive or voluntary associations, and that so violently as to exclude the stimuli of external objects. These two situations of our sensual motions, or ideas, resemble convulsion and epilepsy; as in the former the stimulus of external objects is still perceived, but not in the latter. Whence this disease, so far from being connected with sleep, though it has by universal mistake acquired its name from it, arises from excess of volition, and not from a suspension of it; and though, like other kinds of epilepsy, it often attacks the patients in their sleep, yet those two, whom I saw, were more frequently seized with it while awake, the sleep-walking being a part of the reverie. See Sect. XIX. and XXXIV. 3. and Class II. 1. 7. 4. and III. 1. 2. 18. M. M. Opium in large doses before the expected paroxysm. 10. _Asthma convulsivum._ The fits of convulsive asthma return at periods, and are attended with cold extremities, and so far resemble the access of an intermittent fever; but, as the lungs are not sensible to the pain of cold, a shivering does not succeed, but instead of it violent efforts of respiration; which have no tendency, as in the humoral asthma, to dislodge any offending material, but only to relieve the pain by exertion, like the shuddering in the beginning of ague-fits, as explained Class III. 1. 1. 2. The insensibility of the lungs to cold is observable on going into frosty air from a warm room; the hands and face become painfully cold, but no such sensation is excited in the lungs; which is another argument in favour of the existence of a peculiar set of nerves for the purpose of perceiving the universal fluid matter of heat, in which all things are immersed. See Sect. XIV. 6. Yet are the lungs nevertheless very sensible to the deficiency of oxygen in the atmosphere, as all people experience, when they go into a room crowded with company and candles, and complain, that it is so close, they can scarcely breathe; and the same in some hot days in summer. There are two diseases, which bear the name of asthma. The first is the torpor or inability of the minute vessels of the lungs, consisting of the terminations of the pulmonary and bronchial arteries and veins, and their attendant lymphatics; in this circumstance it resembles the difficulty of breathing, which attends cold bathing. If this continues long, a congestion of fluid in the air-cells succeeds, as the absorbent actions cease completely before the secerning ones; as explained in Class I. 1. 2. 3. And the coldness, which attends the inaction of these vessels, prevents the usual quantity of exhalation. Some fits cease before this congestion takes place, and in them no violent sweating nor any expuition of phlegm occurs. This is the humoral asthma, described at Class II. 1. 1. 7. The second kind of asthma consists in the convulsive actions in consequence of the disagreeable sensations thus induced; which in some fits of asthma are very great, as appears in the violent efforts to raise the ribs, and to depress the diaphragm, by lifting the shoulders. These, so long as they contribute to remove the cause of the disease, are not properly convulsions, but exertions immediately caused by sensation; but in this kind of asthma they are only efforts to relieve pain, and are frequently preceded by other epileptic convulsions. These two kinds of asthmas have so many resembling features, and are so frequently intermixed, that it often requires great attention to distinguish them; but as one of them is allied to anasarca, and the other to epilepsy, we shall acquire a clearer idea of them by comparing them with those disorders. A criterion of the humoral or hydropic asthma is, that it is relieved by copious sweats about the head and breast, which are to be ascribed to the sensitive exertions of the pulmonary vessels to relieve the pain occasioned by the anasarcous congestion in the air-cells; and which is effected by the increased absorption of the mucus, and its elimination by the retrograde action of those lymphatics of the skin, whose branches communicate with the pulmonary ones; and which partial sweats do not easily admit of any other explanation. See Class I. 3. 2. 8. Another criterion of it is, that it is generally attended with swelled legs, or other symptoms of anasarca. A criterion of the convulsive asthma may be had from the absence of these cold clammy sweats of the upper part of the body only, and from the patient having occasionally been subject to convulsions of the limbs, as in the common epilepsy. It may thus frequently happen, that in the humoral asthma some exertions of the lungs may occur, which may not contribute to discharge the anasarcous lymph, but may be efforts simply to relieve pain; besides those efforts, which produce the increased absorption and elimination of it; and thus we have a bodily disease resembling in this circumstance the reverie, in which both sensitive and voluntary motions are at the same time, or in succession, excited for the purpose of relieving pain. It may likewise sometimes happen, that the disagreeable sensation, occasioned by the congestion of lymph in the air-cells in the humoral or hydropic asthma, may induce voluntary convulsions of the respiratory organs only to relieve the pain, without any sensitive actions of the pulmonary absorbents to absorb and eliminate the congestion of serous fluid; and thus the same cause may occasionally induce either the humoral or convulsive asthma. The humoral asthma has but one remote cause, which is the torpor of the pulmonary vessels, like that which occurs on going into the cold bath; or the want of absorption of the pulmonary lymphatics to take up the lymph effused into the air-cell. Whereas the convulsive asthma, like other convulsions, or epilepsies, may be occasioned by pain in almost any remote part of the system. But in some of the adult patients in this disease, as in many epilepsies, I have suspected the remote cause to be a pain of the liver, or of the biliary ducts. The asthmas, which have been induced in consequence of the recess of eruptions, especially of the leprous kind, countenance this opinion. One lady I knew, who for many years laboured under an asthma, which ceased on her being afflicted with pain, swelling, and distortion of some of her large joints, which were esteemed gouty, but perhaps erroneously. And a young man, whom I saw yesterday, was seized with asthma on the retrocession, or ceasing of eruptions on his face. The convulsive asthma, as well as the hydropic, are more liable to return in hot weather; which may be occasioned by the less quantity of oxygen existing in a given quantity of warm air, than of cold, which can be taken into the lungs at one inspiration. They are both most liable to occur after the first sleep, which is therefore a general criterion of asthma. The cause of this is explained in Sect. XVIII. 15. and applies to both of them, as our sensibility to internal uneasy sensation increases during sleep. When children are gaining teeth, long before they appear, the pain of the gums often induces convulsions. This pain is relieved in some by sobbing and screaming; but in others a laborious respiration is exerted to relieve the pain; and this constitutes the true asthma convulsivum. In other children again general convulsions, or epileptic paroxysms, are induced for this purpose; which, like other epilepsies, become established by habit, and recur before the irritation has time to produce the painful sensation, which originally caused them. The asthma convulsivum is also sometimes induced by worms, or by acidity in the stomachs of children, and by other painful sensations in adults; in whom it is generally called nervous asthma, and is often joined with other epileptic symptoms. This asthma is distinguished from the peripneumony, and from the croup, by the presence of fever in the two latter. It is distinguished from the humoral asthma, as in that the patients are more liable to run to the cold air for relief, are more subject to cold extremities, and experience the returns of it more frequently after their first sleep. It is distinguished from the hydrops thoracis, as that has no intervals, and the patient sits constantly upright, and the breath is colder; and, where the pericardium is affected, the pulse is quick and unequal. See Hydrops Thoracis, I. 2. 3. 14. M. M. Venesection once. A cathartic with calomel once. Opium. Assafoetida. Warm bath. If the cause can be detected, as in toothing or worms, it should be removed. As this species of asthma is so liable to recur during sleep, like epileptic fits, as mentioned in Section XVIII. 15. there was reason to believe, that the respiration of an atmosphere mixed with hydrogen, or any other innocuous air, which might dilute the oxygen, would be useful in preventing the paroxysms by decreasing the sensibility of the system. This, I am informed by Dr. Beddoes, has been used with decided success by Dr. Ferriar. See Class II. 1. 1. 7. 11. _Asthma dolorificum._ Angina pectoris. The painful asthma was first described by Dr. Heberden in the Transactions of the College; its principal symptoms consist in a pain about the middle of the sternum, or rather lower, on every increase of pulmonary or muscular exertion, as in walking faster than usual, or going quick up a hill, or even up stairs; with great difficulty of breathing, so as to occasion the patient instantly to stop. A pain in the arms about the insertion of the tendon of the pectoral muscle generally attends, and a desire of resting by hanging on a door or branch of a tree by the arms is sometimes observed. Which is explained in Class I. 2. 3. 14. and in Sect. XXIX. 5. 2. These patients generally die suddenly; and on examining the thorax no certain cause, or seat, of the disease has been detected; some have supposed the valves of the arteries, or of the heart, were imperfect; and others that the accumulation of fat about this viscus or the lungs obstructed their due action; but other observations do not accord with these suppositions. Mr. W----, an elderly gentleman, was seized with asthma during the hot part of last summer; he always waked from his first sleep with difficult respiration, and pain in the middle of his sternum, and after about an hour was enabled to sleep again. As this had returned for about a fortnight, it appeared to me to be an asthma complicated with the disease, which Dr. Heberden has called angina pectoris. It was treated by venesection, a cathartic, and then by a grain of opium given at going to bed, with ether and tincture of opium when the pain or asthma required, and lastly with the bark, but was several days before it was perfectly subdued. This led me to conceive, that in this painful asthma the diaphragm, as well as the other muscles of respiration, was thrown into convulsive action, and that the fibres of this muscle not having proper antagonists, a painful fixed spasm of it, like that of the muscles in the calf of the leg in the cramp, might be the cause of death in the angina pectoris, which I have thence arranged under the name of painful asthma, and leave for further investigation. From the history of the case of the late much lamented John Hunter, and from the appearances after death, the case seems to have been of this kind, complicated with vertigo and consequent affection of the stomach. The remote cause seems to have arisen from ossifications of the coronary arteries; and the immediate cause of his death from fixed spasm of the heart. Other histories and dissections are still required to put this matter out of doubt; as it is possible, that either a fixed spasm of the diaphragm, or of the heart, which are both furnished with but weak antagonists, may occasion sudden death; and these may constitute two distinct diseases. Four patients I have now in my recollection, all of whom I believed to labour under the angina pectoris in a great degree; which have all recovered, and have continued well three or four years by the use, as I believe, of issues on the inside of each thigh; which were at first large enough to contain two pease each, and afterwards but one. They took besides some slight antimonial medicine for a while, and were reduced to half the quantity or strength of their usual potation of fermented liquor. The use of femoral issues in angina pectoris was first recommended by Dr. Macbride, physician at Dublin, Med. Observ. & Enquir. Vol. VI. And I was further induced to make trial of them, not only because the means which I had before used were inadequate, but from the ill effect I once observed upon the lungs, which succeeded the cure of a small sore beneath the knee; and argued conversely, that issues in the lower limbs might assist a difficult respiration. Mrs. L----, about fifty, had a small sore place about the size of half a pea on the inside of the leg a little below the knee. It had discharged a pellucid fluid, which she called a ley-water, daily for fourteen years, with a great deal of pain; on which account she applied to a surgeon, who, by means of bandage and a saturnine application, soon healed the sore, unheedful of the consequences. In less than two months after this I saw her with great difficulty of breathing, which with universal anasarca soon destroyed her. The theory of the double effect of issues, as above related, one in relieving by their presence the asthma dolorificum, and the other in producing by its cure an anasarca of the lungs, is not easy to explain. Some similar effects from cutaneous eruptions and from blisters are mentioned in Class I. 1. 2. 9. In these cases it seems probable, that the pain occasioned by issues, and perhaps the absorption of a small quantity of aerated purulent matter, stimulate the whole system into greater energy of action, and thus prevent the torpor which is the beginning of so many diseases. In confirmation of this effect of pain on the system, I remember the case of a lady of an ingenious and active mind, who, for many of the latter years of her life, was perpetually subject to great pains of her head from decaying teeth. When all her teeth were gone, she became quite low spirited, and melancholy in the popular sense of that word, and after a year or two became universally dropsical and died. M. M. Issues in the thighs. Five grains of rhubarb, and one sixth of a grain of emetic tartar every night for some months, with or without half a grain of opium. No stronger liquor than small beer, or wine diluted with twice its quantity of water. Since I wrote the above I have seen two cases of hydrops thoracis, attended with pain in the left arm, so as to be mistaken for asthma dolorificum, in which femoral issues, though applied early in the disease, had no effect. 12. _Stridor dentium._ The clattering of the teeth on going into cold water, or in the beginning of ague-fits, is an exertion along with the tremblings of the skin to relieve the pain of cold. The teeth and skin being more sensible to cold than the more internal parts, and more exposed to it, is the reason that the muscles, which serve them, are thrown into exertion from the pain of cold rather than those of respiration, as in screaming from more acute pain. Thus the poet, Put but your toes into cold water, Your correspondent teeth will clatter. PRIOR. In more acute pains the jaws are gnashed together with great vehemence, insomuch that sometimes the teeth are said to have been broken by the force. See Sect. XXXIV. 1. 3. In these cases something should be offered to the patient to bite, as a towel, otherwise they are liable to tear their own arms, or to bite their attendants, as I have witnessed in the painful epilepsy. 13. _Tetanus trismus._ Cramp. The tetanus consists of a fixed spasm of almost all the muscles of the body; but the trismus, or locked jaw, is the most frequent disease of this kind. It is generally believed to arise from sympathy with an injured tendon. In one case where it occurred in consequence of a broken ankle from a fall from a horse, it was preceded by evident hydrophobia. Amputation was advised, but not submitted to; two wounds were laid into one with scissors, but the patient died about the seventh day from the accident. In this case the wounded tendon, like the wounds from the bite of a mad dog, did not produce the hydrophobia, and then the locked jaw, till several days after the accident. I twice witnessed the locked jaw from a pain beneath the sternum, about the part where it is complained of in painful asthma, or angina pectoris, in the same lady at some years distance of time. The last time it had continued two days, and she wrote her mind, or expressed herself by signs. On observing a broken tooth, which made a small aperture into her mouth, I rolled up five grains of opium like a worm about an inch long, and introducing it over the broken tooth, pushed it onward by means of a small crow-quill; as it dissolved I observed she swallowed her saliva, and in less than half an hour, she opened her mouth and conversed as usual. Men are taught to be ashamed of screaming from pain in their early years; hence they are prone to exert the muscles of the jaws instead, which they have learnt to exert frequently and violently from their infancy; whence the locked jaw. This and the following spasm have no alternate relaxations, like the preceding ones; which is perhaps owing, first, to the weakness of their antagonist muscles, those which elevate the jaw being very strong for the purpose of biting and masticating hard substances, and for supporting the under jaw, with very weak antagonist muscles; and secondly, to their not giving sufficient relief even for a moment to the pain, or its preceding irritation, which excited them. M. M. Opium in very large quantities. Mercurial ointment used extensively. Electricity. Cold bath. Dilate the wound, and fill it with lint moistened with spirit of turpentine; which inflames the wound, and cures or prevents the convulsions. See a case, Transact. of American Society, Vol. II. p. 227. Wine in large quantities in one case was more successful than opium; it probably inflames more, which in this disease is desirable. Between two or three ounces of bark, and from a quart to three pints of wine a day, succeeded better than opium. Ib. 14. _Tetanus dolorificus._ Painful cramp. This kind of spasm most frequently attacks the calf of the leg, or muscles of the toes; it often precedes paroxysms of gout, and appears towards the end of violent diarrhoea, and from indigestion, or from acid diet. In these cases it seems to sympathize with the bowels, but is also frequently produced by the pain of external cold, and to the too great previous extension of the muscles, whence some people get the cramp in the extensor muscles of the toes after walking down hill, and of those of the calf of the leg after walking up a steep eminence. For the reason why these cramps commence in sleep, see Sect. XVIII. 15. The muscle in this disease contracts itself to relieve some smaller pain, either from irritation or association, and then falls into great pain itself, from the too great action of its own fibres. Hence any muscle, by being too vehemently exerted, falls into cramp, as in swimming too forcibly in water, which is painfully cold; and a secondary pain is then induced by the too violent contraction of the muscle; though the pain, which was the cause of the contraction, ceases. Which accounts for the continuance of the contraction, and distinguishes this disease from other convulsions, which are relaxed and exerted alternately. Hence whatever may be the cause of the primary pain, which occasions the cramp of the calf of the leg, the secondary one is relievable by standing up, and thus by the weight of the body on the toes forcibly extending the contracted muscles. For the cause, which induces these muscles of the calf of the leg to fall into more violent contraction than other spasmodic muscles, proceeds from the weakness of their antagonist muscles; as they are generally extended again after action by the weight of the body on the balls of the toes. See the preceding article. M. M. Rub the legs with camphor dissolved in oil, and let the patient wear stockings in bed. If a foot-board be put at the bed's feet, and the bed be so inclined, that he will rest a little with his toes against the foot-board, that pressure is said to prevent the undue contractions of the musculi gastrocnemii, which constitute the calf of the leg. In gouty patients, or where the bowels are affected with acidity, half a grain of opium, and six grains of rhubarb, and six of chalk, every night. Flesh-meat to supper. A little very weak warm spirit and water may be taken for present relief, when these cramps are very troublesome to weak or gouty patients. 15. _Hydrophobia._ Dread of water generally attending canine madness. I was witness to a case, where this disease preceded the locked jaw from a wound in the ankle, occasioned by a fall from a horse; as mentioned in the preceding article. It came on about the sixth day after the accident; when the patient attempted to swallow fluids, he became convulsed all over from the pain of this attempt, and spurted them out of his mouth with violence. It is also said to happen in some hysterical cases. Hence it seems rather the immediate consequence of a pained tendon, than of a contagious poison. And is so far analogous to tetanus, according with the opinions of Doctor Rusch and Doctor Percival. In other respects, as it is produced by the saliva of an enraged animal instilled into a wound, it would seem analogous to the poison of venomous animals. And from the manner of its access so long after the bite, and of its termination in a short time, it would seem to resemble the progress of contagious fevers. See Sect. XXII. 3. 3. If the patient was bitten in a part, which could be totally cut away, as a finger, even after the hydrophobia appears, it is probable it might cure it; as I suspect the cause still remains in the wounded tendon, and not in a diffused infection tainting the blood. Hence there are generally uneasy sensations, as cold or numbness, in the old cicatrix, before the hydrophobia commences. See a case in Medical Communications, Vol. II. p. 190. If the diseased tendon could be inflamed without cutting it out, as by cupping, or caustic, or blister after cupping, and this in the old wound long since healed, after the hydrophobia commences, might prevent the spasms about the throat. As inflaming the teeth by the use of mercury is of use in some kinds of hemicrania. Put spirit of turpentine on the wound, wash it well. See Class I. 3. 1. 11. IV. 1. 2. 7. M. M. Wine, musk, oil, internally. Opium, mercurial ointment, used extensively. Mercurial fumigation. Turpeth mineral. To salivate the patient as soon as possible. Exsection or a caustic on the scar, even after the appearance of hydrophobia. Put a tight bandage on the limb above the scar of the old wound to benumb the pained tendon, however long the wound may have been healed. Could a hollow catheter of elastic gum, caoutchouc, be introduced into the oesophagus by the mouth or nostril, and liquid nourishment be thus conveyed into the stomach? See Desault's Journal, Case I. where, in an ulcer of the mouth, such a catheter was introduced by the nostril, and kept in the oesophagus for a month, by which means the patient was nourished and preserved. It is recommended by Dr. Bardsley to give oil internally by a similar method contrived by Mr. John Hunter. He covered a probang with the skin of a small eel, or the gut of a lamb or cat. It was tied up at one end above and below the sponge, and a slit made above the upper ligature; to the other end of the eel-skin or gut was fixed a bladder and pipe. The probang thus covered was introduced into the stomach, and the liquid food or medicine was put into the bladder and squeezed down through the eel-skin. Mem. of Society at Manchester. See Class I. 2. 3. 25. Dr. Bardsley has endeavoured to prove, that dogs never experience the hydrophobia, or canine madness, without having been previously bitten or infected; and secondly, that the disease in this species of animal always shews itself in five or six weeks; and concludes from hence, that this dreadful malady might be annihilated by making all the dogs in Great Britain perform a kind of quarantine, by shutting them up for a certain number of weeks. Though the disease from the bite of the mad dog is perhaps more analogous to those from the wounds inflicted by venomous animals than to those from other contagious matter, yet these observations are well worthy further attention; which the author promises. * * * * * ORDO I. _Increased Volition._ GENUS II. _With increased Actions of the Organs of Sense._ In every species of madness there is a peculiar idea either of desire or aversion, which is perpetually excited in the mind with all its connections. In some constitutions this is connected with pleasurable ideas without the exertion of much muscular action, in others it produces violent muscular action to gain or avoid the object of it, in others it is attended with despair and inaction. Mania is the general word for the two former of these, and melancholia for the latter; but the species of them are as numerous as the desires and aversions of mankind. In the present age the pleasurable insanities are most frequently induced by superstitious hopes of heaven, by sentimental love, and by personal vanity. The furious insanities by pride, anger, revenge, suspicion. And the melancholy ones by fear of poverty, fear of death, and fear of hell; with innumerable others. Quicquid agunt homines, votum, timor, ira, voluptas, Gaudia, discursus, nostri est farrago libelli. JUVEN. I. 85. This idea, however, which induces madness or melancholy, is generally untrue; that is, the object is a mistaken fact. As when a patient is persuaded he has the itch, or venereal disease, of which he has no symptom, and becomes mad from the pain this idea occasions. So that the object of madness is generally a delirious idea, and thence cannot be conquered by reason; because it continues to be excited by painful sensation, which is a stronger stimulus than volition. Most frequently pain of body is the cause of convulsion, which is often however exchanged for madness; and a painful delirious idea is most frequently the cause of madness originally, but sometimes of convulsion. Thus I have seen a young lady become convulsed from a fright, and die in a few days; and a temporary madness frequently terminates the paroxysms of the epilepsia dolorifica, and an insanity of greater permanence is frequently induced by the pains or bruises of parturition. Where the patient is debilitated a quick pulse sometimes attends insane people, which is nevertheless generally only a symptom of the debility, owing to the too great expenditure of sensorial power; or of the paucity of its production, as in inirritative, or in sensitive inirritated fever. See III. 1. 1. But nevertheless where the quick pulse is permanent, it shews the presence of fever; and as the madness then generally arises from the disagreeable sensations attending the fever, it is so far a good symptom; because when the fever is cured, or ceases spontaneously, the insanity most frequently vanishes at the same time. The stimulus of so much volition supports insane people under variety of hardships, and contributes to the cure of diseases from debility, as sometimes occurs towards the end of fevers. See Sect. XXXIV. 2. 5. And, on the same account, they bear large doses of medicines to procure any operation on them; as emetics, and cathartics, which, before they produce their effect in inverting the motions of the stomach in vomiting, or of the absorbents of the bowels in purging, must first weaken the natural actions of those organs, as shewn in Sect. XXXV. 1. 3. From these considerations it appears, that the indications of cure must consist in removing the cause of the pain, whether it arises from a delirious idea, or from a real fact, or from bodily disease; or secondly, if this cannot be done, by relieving the pain in consequence of such idea or disease. The first is sometimes effected by presenting frequently in a day contrary ideas to shew the fallacy, or the too great estimation, of the painful ideas. 2dly. By change of place, and thus presenting the stimulus of new objects, as a long journey. 3dly. By producing forgetfulness of the idea or object, which causes their pain; by removing all things which recal it to their minds; and avoiding all conversation on similar subjects. For I suppose no disease of the mind is so perfectly cured by other means as by forgetfulness. Secondly, the pain in consequence of the ideas or bodily diseases above described is to be removed, first, by evacuations, as venesection, emetics, and cathartics; and then by large doses of opium, or by the vertigo occasioned by a circulating swing, or by a sea-voyage, which, as they affect the organs of sense as well as evacuate the stomach, may contribute to answer both indications of cure. Where maniacs are outrageous, there can be no doubt but coercion is necessary; which may be done by means of a straight waistcoat; which disarms them without hurting them; and by tying a handkerchief round their ankles to prevent their escape. In others there can be no doubt, but that confinement retards rather than promotes their cure; which is forwarded by change of ideas in consequence of change of place and of objects, as by travelling or sailing. The circumstances which render confinement necessary, are first, if the lunatic is liable to injure others, which must be judged of by the outrage he has already committed. 2dly. If he is likely to injure himself; this also must be judged of by the despondency of his mind, if such exists. 3dly. If he cannot take care of his affairs. Where none of these circumstances exist, there should be no confinement. For though the mistaken idea continues to exist, yet if no actions are produced in consequence of it, the patient cannot be called insane, he can only be termed delirious. If every one, who possesses mistaken ideas, or who puts false estimates on things, was liable to confinement, I know not who of my readers might not tremble at the sight of a madhouse! The most convenient distribution of insanities will be into general, as mania mutabilis, studium inane, and vigilia; and into partial insanities. These last again may be subdivided into desires and aversions, many of which are succeeded by pleasurable or painful ideas, by fury or dejection, according to the degree or violence of their exertions. Hence the analogy between the insanities of the mind, and the convulsions of the muscles described in the preceding genus, is curiously exact. The convulsions without stupor, are either just sufficient to obliterate the pain, which occasions them; or are succeeded by greater pain, as in the convulsio dolorifica. So the exertions in the mania mutabilis are either just sufficient to allay the pain which occasions them, and the patient dwells comparatively in a quiet state; or those exertions excite painful ideas, which are succeeded by furious discourses, or outrageous actions. The studium inane, or reverie, resembles epilepsy, in which there is no sensibility to the stimuli of external objects. Vigilia, or watchfulness, may be compared to the general writhing of the body; which is just a sufficient exertion to relieve the pain which occasions it. Erotomania may be compared to trismus, or other muscular fixed spasm, without much subsequent pain; and mæror to cramp of the muscles of the leg, or other fixed spasm with subsequent pain. All these coincidences contribute to shew, as explained in Sect. III. 5, that our ideas are motions of the immediate organs of sense obeying the same laws as our muscular motions. The violence of action accompanying insanity depends much on the education of the person; those who have been proudly educated with unrestrained passions, are liable to greater fury; and those, whose education has been humble, to greater despondency. Where the delirious idea, above described, produces pleasurable sensations, as in personal vanity or religious enthusiasm; it is almost a pity to snatch them from their fool's paradise, and reduce them again to the common lot of humanity; lest they should complain of their cure, like the patient described in Horace, --------Pol! me occidistis, amici, Non servastis, ait, cui sic extorta voluptas, Et demptus per vim mentis gratissimus error! The disposition to insanity, as well as to convulsion, is believed to be hereditary; and in consequence to be induced in those families from slighter causes than in others. Convulsions have been shewn to have been most frequently induced by pains owing to defect of stimulus, as the shuddering from cold, and not from pains from excess of stimulus, which are generally succeeded by inflammation. But insanities are on the contrary generally induced by pains from excess of stimulus, as from the too violent actions of our ideas, as in common anger, which is an insanity of short duration; for insanities generally, though not always, arise from pains of the organs of sense; but convulsions generally, though not always, from pains of the membranes or glands. And it has been previously explained, that though the membrane and glands, as the stomach and skin, receive great pain from want of stimulus; yet that the organs of sense, as the eye and ear, receive no pain from defect of stimulus. Hence it follows, that the constitutions most liable to convulsion, are those which most readily become torpid in some part of the system, that is, which possess less irritability; and that those most liable to insanity, are such as have excess of sensibility; and lastly, that these two circumstances generally exist in the same constitution; as explained in Sect. XXXI. 2. on Temperaments. These observations explain why epilepsy and insanity frequently succeed or reciprocate with each other, and why inirritable habits, as scrophulous ones, are liable to insanity, of which I have known some instances. In many cases however there is no appearance of the disposition to epilepsy or insanity of the parent being transmitted to the progeny. First, where the insanity has arisen from some violent disappointment, and not from intemperance in the use of spirituous liquors. Secondly, where the parent has acquired the insanity or epilepsy by habits of intoxication after the procreation of his children. Which habits I suppose to be the general cause of the disposition to insanity in this country. See Class III. 1. 1. 7. As the disposition to gout, dropsy, epilepsy, and insanity, appears to be produced by the intemperate use of spirituous potation, and is in all of them hereditary; it seems probable, that this disposition gradually increases from generation to generation, in those families which continue for many generations to be intemperate in this respect; till at length these diseases are produced; that is, the irritability of the system gradually is decreased by this powerful stimulus, and the sensibility at the same time increased, as explained in Sect. XXXI. 1. and 2. This disposition is communicated to the progeny, and becomes still increased, if the same stimulus be continued, and so on by a third and fourth generation; which accounts for the appearance of epilepsy in the children of some families, where it was never known before to have existed, and could not be ascribed to their own intemperance. A parity of reasoning shews, that a few sober generations may gradually in the same manner restore a due degree of irritability to the family, and decrease the excess of sensibility. From hence it would appear probable, that scrophula and dropsy are diseases from inirritability; but that in epilepsy and insanity an excess of sensibility is added, and the two faulty temperaments are thus conjoined. SPECIES. 1. _Mania mutabilis._ Mutable madness. Where the patients are liable to mistake ideas of sensation for those from irritation, that is, imaginations for realities, if cured of one source of insanity, they are liable in a few months to find another source in some new mistaken or imaginary idea, and to act from this new idea. The idea belongs to delirium, when it is an imaginary or mistaken one; but it is the voluntary actions exerted in consequence of this mistaken idea, which constitute insanity. In this disease the patient is liable carefully to conceal the object of his desire or aversion. But a constant inordinate suspicion of all people, and a carelessness of cleanliness, and of decency, are generally concomitants of madness. Their designs cannot be counteracted, till you can investigate the delirious idea or object of their insanity; but as they are generally timid, they are therefore less to be dreaded. Z. Z. called a young girl, one of his maid-servants, into the parlour, and, with cocked pistols in his hands, ordered her to strip herself naked; he then inspected her with some attention, and dismissed her untouched. Then he stripped two of his male servants in the same manner, to the great terror of the neighbourhood. After he was secured, with much difficulty he was persuaded to tell me, that he had got the itch, and had examined some of his servants to find out from whom he had received it; though at the same time there was not a spot to be seen on his hands, or other parts. The outrages in consequence of this false idea were in some measure to be ascribed to the pride occasioned by unrestrained education, affluent wealth, and dignified family. Madness is sometimes produced by bodily pain, particularly I believe of a diseased liver, like convulsion and epilepsy; at other times it is caused by very painful ideas occasioned by external circumstances, as of grief or disappointment; but the most frequent cause of insanity arises from the pain of some imaginary or mistaken idea; which may be termed hallucinatio maniacalis. This hallucination of one of the senses is often produced in an instant, and generally becomes gradually weakened in process of time, by the perpetual stimulus of external objects, or by the successions of other catenations of ideas, or by the operations of medicines; and when the maniacal hallucination ceases, or is forgotten, the violent exertions cease, which were in consequence of it, and the disease is cured. Mr. ----, a clergyman, about forty years of age, who was rather a weak man, happened to be drinking wine in jocular company, and by accident swallowed a part of the seal of a letter, which he had just then received; one of his companions seeing him alarmed, cried out in humour, "It will seal your bowels up." He became melancholy from that instant, and in a day or two refused to swallow any kind of nourishment. On being pressed to give a reason for this refusal, he answered, he knew nothing would pass through him. A cathartic was given, which produced a great many evacuations, but he still persisted, that nothing passed through him; and though he was frightened into taking a little broth once or twice by threats, yet he soon ceased intirely to swallow any thing, and died in consequence of this insane idea. Miss ----, a sensible and ingenious lady, about thirty, said she had seen an angel; who told her, that she need not eat, though all others were under the necessity of supporting their earthly existence by food. After fruitless persuasions to take food, she starved herself to death.--It was proposed to send an angel of an higher order to tell her, that now she must begin to eat and drink again; but it was not put into execution. Mrs. ----, a lady between forty and fifty years of age, imagined that she heard a voice say to her one day, as she was at her toilet, "Repent, or you will be damned." From that moment she became melancholy, and this hallucination affected her in greater or less degree for about two years; she then recovered perfectly, and is now a cheerful old woman. Mrs. ----, a farmer's wife, going up stairs to dress, found the curtains of her bed drawn, and on undrawing them, she believed that she saw the corpse of her sister, who was then ill at the distance of twenty miles, and became from that time insane; and as her sister died about the time, she could not be produced to counteract the insane hallucination, but she perfectly recovered in a few months. Mrs. ----, a most elegant, beautiful, and accomplished lady, about twenty-two years of age, had been married about two months to an elegant, polished, and affluent young man, and it was well known to be a love-match on both sides. She suddenly became melancholy, and yet not to so great a degree, but that she could command herself to do the honours of her table with grace and apparent ease. After many days intreaty, she at length told me, that she thought her marrying her husband had made him unhappy; and that this idea she could not efface from her mind day or night. I withstood her being confined, as some had advised, and proposed a sea-voyage to her, with expectation that the sickness, as well as change of objects, might remove the insane hallucination, by introducing other energetic ideas; this was not complied with, but she travelled about England with her friends and her husband for many months, and at length perfectly recovered, and is now I am informed in health and spirits. These cases are related to shew the utility of endeavouring to investigate the maniacal idea, or hallucination; as it may not only acquaint us with the probable designs of the patient, from whence may be deduced the necessity of confinement; but also may some time lead to the most effectual plan of cure. I received good information of the truth of the following case, which was published a few years ago in the newspapers. A young farmer in Warwickshire, finding his hedges broke, and the sticks carried away during a frosty season, determined to watch for the thief. He lay many cold hours under a hay-stack, and at length an old woman, like a witch in a play, approached, and began to pull up the hedge; he waited till she had tied up her bottle of sticks, and was carrying them off, that he might convict her of the theft, and then springing from his concealment, he seized his prey with violent threats. After some altercation, in which her load was left upon the ground, she kneeled upon her bottle of sticks, and raising her arms to heaven beneath the bright moon then at the full, spoke to the farmer already shivering with cold, "Heaven grant, that thou never mayest know again the blessing to be warm." He complained of cold all the next day, and wore an upper coat, and in a few days another, and in a fortnight took to his bed, always saying nothing made him warm, he covered himself with very many blankets, and had a sieve over his face, as he lay; and from this one insane idea he kept his bed above twenty years for fear of the cold air, till at length he died. M. M. As mania arises from pain either of our muscles or organs of sense, the arts of relieving pain must constitute the method of cure. See Sect. XXXIV. 3. 4. Venesection. Vomits of from five grains to ten of emetic tartar, repeated every third morning for three or four times; with solution of gum-ammoniac, and soluble tartar, so as to purge gently every day. Afterwards warm bath for two or three hours a day. Opium in large doses. Bark. Steel. Dr. Binns gave two scruples (40 grains) of solid opium at a dose, and twenty grains four hours afterwards; which restored the patient. Dr. Brandreth gave 400 drops of laudanum to a maniac in the greatest possible furor, and in a few hours he became calm and rational. Med. Comment for 1791, p. 384. _Prognostic._ The temporary quick pulse attending some maniacal cases is simply a symptom of debility, and is the consequence of too great exertions; but a permanent quick pulse shews the presence of fever, and is frequently a salutary sign; because, if the life of the patient be safe, when the fever ceases, the insanity generally vanishes along with it, as mentioned above. In this case the kind of fever must direct the method of curing the insanity; which must consist of moderate evacuations and diluents, if the pulse be strong; or by nutrientia, bark, and small doses of opium, if the pulse be weak. Where the cause is of a temporary nature, as in puerperal insanity, there is reason to hope, that the disease will cease, when the bruises, or other painful sensations attending this state, are removed. In these cases the child should be brought frequently to the mother, and applied to her breast, if she will suffer it, and this whether she at first attends to it or not; as by a few trials it frequently excites the storgè, or maternal affection, and removes the insanity, as I have witnessed. When the madness is occasioned by pain of the teeth, which I believe is no uncommon case, these must be extracted; and the cure follows the extinction of the pain. There is however some difficulty in detecting the delinquent tooth in this case, as in hemicrania, unless by its apparent decay, or by some previous information of its pain having been complained of; because the pain of the tooth ceases, as soon as the exertions of insanity commence. When a person becomes insane, who has a family of small children to solicit his attention, the prognostic is very unfavourable; as it shews the maniacal hallucination to be more powerful than those ideas which generally interest us the most. 2. _Studium inane._ Reverie consists of violent voluntary exertions of ideas to relieve pain, with all the trains or tribes connected with them by sensations or associations. It frequently alternates with epileptic convulsions; with which it corresponds, in respect to the insensibility of the mind to the stimuli of external objects, in the same manner as madness corresponds with common convulsion, in the patient's possessing at the same time a sensibility of the stimuli of external objects. Some have been reported to have been involved in reverie so perfectly, as not to have been disturbed by the discharge of a cannon; and others to have been insensible to torture, as the martyrs for religious opinions; but these seem more properly to belong to particular insanities than to reverie, like nostalgia and erotomania. Reverie is distinguished from madness as described above; and from delirium, because the trains of ideas are kept consistent by the power of volition, as the person reasons and deliberates in it. Somnambulismus is a part of reverie, the latter consisting in the exertions of the locomotive muscles, and the former of the exertions of the organs of sense; see Class III. 1. 1. 9. and Sect. XIX. both which are mixed, or alternate with each other, for the purpose of relieving pain. When the patients in reverie exert their volition on their organs of sense, they can occasionally perceive the stimuli of external objects, as explained in Sect. XIX. And in this case it resembles sometimes an hallucination of the senses, as there is a mixture of fact and imagination in their discourse; but may be thus distinguished: hallucinations of the lenses are allied to delirium, and are attended generally with quick pulse, and other symptoms of great debility; but reverie is without fever, and generally alternates with convulsions; and so much intuitive analogy (see Sect. XVII. 3. 7.) is retained in its paroxysms, as to preserve a consistency in the trains of ideas. Miss G----, whose case is related in Sect. III. 5. 8. said, as I once sat by her, "My head is fallen off, see it is rolled to that corner of the room, and the little black dog is nibbling the nose off." On my walking to the place which she looked at, and returning, and assuring her that her nose was unhurt, she became pacified, though I was doubtful whether she attended to me. See Class III. 1. 1. 9. and Class III. 1. 2. 2. M. M. Large doses of opium given before the expected paroxysm, as in epilepsia dolorifica, Class III. 1. 1. 8. The hallucinatio studiosa, or false ideas in reverie, differ from maniacal hallucinations above described, as no insane exertions succeed, and in the patients whom I have seen they have always been totally forgotten, when the paroxysm was over. Master ----, a school-boy about twelve years old, after he came out of a convulsion fit and sat up in bed, said to me, "Don't you see my father standing at the feet of the bed, he is come a long way on foot to see me." I answered, no: "What colour is his coat!" He replied, "A drab colour." "And what buttons?" "Metal ones," he answered, and added, "how sadly his legs are swelled." In a few minutes he said, with apparent surprise, "He is gone," and returned to his perfect mind. Other cases are related in Sect. XIX. and XXXIV. 3. and in Class III. 1. 2. 2. with further observations on this kind of hallucination; which however is not the cause of reverie, but constitutes a part of it, the cause being generally some uneasy sensation of the body. 3. _Vigilia._ Watchfulness consists in the unceasing exertion of volition; which is generally caused by some degree of pain either of mind or of body, or from defect of the usual quantity of pleasurable sensation; hence if those, who are accustomed to wine at night, take tea instead, they cannot sleep. The same happens from want of solid food for supper, to those who are accustomed to use it; as in these cases there is pain or defect of pleasure in the stomach. Sometimes the anxiety about sleeping, that is the desire to sleep, prevents sleep; which consists in an abolition of desire or will. This may so far be compared to the impediment of speech described in Sect. XVII. 1. 10. as the interference of the will prevents the effect desired. Another source of watchfulness may be from the too great secretion of sensorial power in the brain, as in phrenzy, and as sometimes happens from the exhibition of opium, and of wine; if the exhaustion of sensorial power by the general actions of the system occasioned by the stimulus of these drugs can be supposed to be less than the increased secretion of it. M. M. 1. Solid food to supper. Wine. Opium. Warm bath. 2. The patient should be told that his want of sleep is of no consequence to his health. 3. Venesection by cupping. Abstinence from wine. 4. A blister by stimulating the skin, and rhubarb by stimulating the bowels, will sometimes induce sleep. Exercise. An uniform sound, as of a pausing drop of water, or the murmur of bees. Other means are described in Sect. XVIII. 20. 4. _Erotomania._ Sentimental love. Described in its excess by romance-writers and poets. As the object of love is beauty, and as our perception of beauty consists in a recognition by the sense of vision of those objects, which have before inspired our love, by the pleasure they have afforded to many of our senses (Sect. XVI. 6); and as brute animals have less accuracy of their sense of vision than mankind (ib.); we see the reason why this kind of love is not frequently observable in the brute creation, except perhaps in some married birds, or in the affection of the mother to her offspring. Men, who have not had leisure to cultivate their taste for visible objects, and who have not read the works of poets and romance-writers, are less liable to sentimental love; and as ladies are educated rather with an idea of being chosen, than of choosing; there are many men, and more women, who have not much of this insanity; and are therefore more easily induced to marry for convenience or interest, or from the flattery of one sex to the other. In its fortunate gratification sentimental love is supposed to supply the purest source of human felicity; and from the suddenness with which many of those patients, described in Species I. of this genus, were seized with the maniacal hallucination, there is reason to believe, that the most violent sentimental love may be acquired in a moment of time, as represented by Shakespeare in the beginning of his Romeo and Juliet. Some have endeavoured to make a distinction between beauty and grace, and have made them as it were rivals for the possession of the human heart; but grace may be defined beauty in action; for a sleeping beauty cannot be called graceful in whatever attitude she may recline; the muscles must be in action to produce a graceful attitude, and the limbs to produce a graceful motion. But though the object of love is beauty, yet the idea is nevertheless much enhanced by the imagination of the lover; which appears from this curious circumstance, that the lady of his passion seldom appears so beautiful to the lover after a few months separation, as his ideas had painted her in his absence; and there is, on that account, always a little disappointment felt for a minute at their next interview from this hallucination of his ideas. This passion of love produces reverie in its first state, which exertion alleviates the pain of it, and by the assistance of hope converts it into pleasure. Then the lover seeks solitude, lest this agreeable reverie should be interrupted by external stimuli, as described by Virgil. Tantum inter densas, umbrosa cacumina, fagos Assiduè veniebat, ibi hæc incondita solus Montibus et sylvis studio jactabat inani. When the pain of love is so great, as not to be relieved by the exertions of reverie, as above described; as when it is misplaced on an object, of which the lover cannot possess himself; it may still be counteracted or conquered by the stoic philosophy, which strips all things of their ornaments, and inculcates "nil admirari." Of which lessons may be found in the meditations of Marcus Antoninus. The maniacal idea is said in some lovers to have been weakened by the action of other very energetic ideas; such as have been occasioned by the death of his favourite child, or by the burning of his house, or by his being shipwrecked. In those cases the violence of the new idea for a while expends so much sensorial power as to prevent the exertion of the maniacal one; and new catenations succeed. On this theory the lover's leap, so celebrated by poets, might effect a cure, if the patient escaped with life. The third stage of this disease I suppose is irremediable; when a lover has previously been much encouraged, and at length meets with neglect or disdain; the maniacal idea is so painful as not to be for a moment relievable by the exertions of reverie, but is instantly followed by furious or melancholy insanity; and suicide, or revenge, have frequently been the consequence. As was lately exemplified in Mr. Hackman, who shot Miss Ray in the lobby of the playhouse. So the poet describes the passion of Dido, ----------Moriamur inultæ?-- At moriamur, ait,--sic, sic, juvat ire sub umbras! The story of Medæa seems to have been contrived by Ovid, who was a good judge of the subject, to represent the savage madness occasioned by ill-requited love. Thus the poet, Earth has no rage like love to hatred turn'd, Nor hell a fury like a woman scorn'd. DRYDEN. 5. _Amor sui._ Vanity consists of an agreeable reverie, and is well ridiculed in the story of Narcissus, who so long contemplated his own beautiful image in the water, that he died from neglect of taking sustenance. I once saw a handsome young man, who had been so much flattered by his parents, that his vanity rose so near to insanity, that one might discern by his perpetual attention to himself, and the difficulty with which he arranged his conversation, that the idea of himself intruded itself at every comma or pause of his discourse. In this degree vanity must afford great pleasure to the possessor; and when it exists within moderate bounds, may contribute much to the happiness of social life. My friend Mr. ---- once complained to me, that he was much troubled with bashfulness in company, and believed that it arose from his want of personal vanity; on this account he determined on a journey to Paris, when Paris was the center of politeness; he there learnt to dress, to dance, and to move his hands gracefully in conversation; and returned a most consummate coxcomb. But after a very few years he relapsed into rusticity of dress and manners. M. M. The cure of vanity may be attempted by excess of flattery, which will at length appear ridiculous, or by its familiarity will cease to be desired. I remember to have heard a story of a nobleman in the court of France, when France had a court, who was so disagreeably vain in conversation, that the king was pleased to direct his cure, which was thus performed. Two gentlemen were directed always to attend him, one was to stand behind his chair, and the other at a respectful distance before him; whenever his lordship began to speak, one of them always pronounced, "Lord Gallimaufre is going to say the best thing in the world." And, as soon as his lordship had done speaking, the other attendant pronounced, "Lord Gallimaufre has spoken the best thing in the world." Till in a few weeks this noble lord was so disgusted with praise that he ceased to be vain; and his majesty dismissed his keepers. 6. _Nostalgia._ Maladie de Pais. Calenture. An unconquerable desire of returning to one's native country, frequent in long voyages, in which the patients become so insane as to throw themselves into the sea, mistaking it for green fields or meadows. The Swiss are said to be particularly liable to this disease, and when taken into foreign service frequently to desert from this cause, and especially after hearing or singing a particular tune, which was used in their village dances, in their native country, on which account the playing or singing this tune was forbid by the punishment of death. Zwingerus. Dear is that shed, to which his soul conforms, And dear that hill, which lifts him to the storms. GOLDSMITH. 7. _Spes religiosa._ Superstitious hope. This maniacal hallucination in its milder state produces, like sentimental love, an agreeable reverie; but when joined with works of supererogation, it has occasioned many enormities. In India devotees consign themselves by vows to most painful and unceasing tortures, such as holding up their hands, till they cannot retract them; hanging up by hooks put into the thick skin over their shoulders, sitting upon sharp points, and other self torments. While in our part of the globe fasting and mortification, as flagellation, has been believed to please a merciful deity! The serenity, with which many have suffered cruel martyrdoms, is to be ascribed to this powerful reverie. Mr. ----, a clergyman, formerly of this neighbourhood, began to bruise and wound himself for the sake of religious mortification, and passed much time in prayer, and continued whole nights alone in the church. As he had a wife and family of small children, I believed the case to be incurable; as otherwise the affection and employment in his family connections would have opposed the beginning of this insanity. He was taken to a madhouse without effect, and after he returned home, continued to beat and bruise himself, and by this kind of mortification, and by sometimes long fasting, he at length became emaciated and died. I once told him in conversation, that "God was a merciful being, and could not delight in cruelty, but that I supposed he worshipped the devil." He was struck with this idea, and promised me not to beat himself for three days, and I believe kept his word for one day. If this idea had been frequently forced on his mind, it might probably have been of service. When these works of supererogation have been of a public nature, what cruelties, murders, massacres, has not this insanity introduced into the world!--A commander, who had been very active in leading and encouraging the bloody deeds of St. Bartholomew's day at Paris, on confessing his sins to a worthy ecclesiastic on his death-bed, was asked, "Have you nothing to say about St. Bartholomew?" "On that day," he replied, "God Almighty was obliged to me!"--The fear of hell is another insanity, which will be spoken of below. 8. _Superbia stemmatis._ Pride of family has frequently formed a maniacal hallucination, which in its mild state has consisted in agreeable reverie, but when it has been so painful as to demand homage from others, it has frequently induced insane exertions. This insanity seems to have existed in the flourishing state of Rome, as now all over Germany, and is attacked by Juvenal with great severity, a small part of which I shall here give as a method of cure. Sat. 8. Say, what avails the pedigree, that brings Thy boasted line from heroes or from kings; Though many a mighty lord, in parchment roll'd, Name after name, thy coxcomb hands unfold; Though wreathed patriots crowd thy marble halls, Or steel-clad warriors frown along the walls; While on broad canvas in the gilded frame All virtues flourish, and all glories flame?-- Say,--if ere noon with idiot laugh you lie Wallowing in wine, or cog the dubious die, Or act unshamed, by each indignant bust, The midnight orgies of promiscuous lust!-- Go, lead mankind to Virtue's holy shrine, With morals mend them, and with arts refine, Or lift, with golden characters unfurl'd, The flag of peace, and still a warring world!-- --So shall with pious hands immortal Fame Wreathe all her laurels round thy honour'd name, High o'er thy tomb with chissel bold engrave, "THE TRULY NOBLE ARE THE GOOD AND BRAVE." 9. _Ambitio._ Inordinate desire of fame. A carelessness about the opinions of others is said by Xenophon to be the source of impudence; certainly a proper regard for what others think of us frequently incites us to virtuous actions, and deters us from vicious ones; and increases our happiness by enlarging our sphere of sympathy, and by flattering our vanity. Abstract what others feel, what others think, All pleasures sicken, and all glories sink. POPE. When this reverie of ambition excites to conquer nations, or to enslave them, it has been the source of innumerable wars, and the occasion of a great devastation of mankind. Cæsar is reported to have boasted, that he had destroyed three millions of his enemies, and one million of his friends. The works of Homer are supposed to have done great injury to mankind by inspiring the love of military glory. Alexander was said to sleep with them always on his pillow. How like a mad butcher amid a flock of sheep appears the hero of the Iliad, in the following fine lines of Mr. Pope, which conclude the twentieth book. His fiery coursers, as the chariot rolls, Tread down whole ranks, and crush out heroes' souls; Dash'd from their hoofs, as o'er the dead they fly, Black bloody drops the smoaking chariot dye;-- The spiky wheels through heaps of carnage tore, And thick the groaning axles dropp'd with gore; High o'er the scene of death ACHILLES stood, All grim with dust, all horrible with blood; Yet still insatiate, still with rage on flame, Such is the lust of never-dying fame! The cure must be taken from moral writers. Woolaston says, Cæsar conquered Pompey; that is, a man whose name consisted of the letters C. æ. s. a. r. conquered a long time ago a man, whose name consisted of the letters P. o. m. p. e. y. and that this is all that remains of either of them. Juvenal also attacks this mode of insanity, Sat. X. 166. --I, demens, et sævas curre per alpes, Ut pueris placeas, et declamatio fias! Which is thus translated by Dr. Johnson, And left a name, at which the world grew pale, To point a moral, or adorn a tale! 10. _Mæror._ Grief. A perpetual voluntary contemplation of all the circumstances of some great loss, as of a favourite child. In general the painful ideas gradually decrease in energy, and at length the recollection becomes more tender and less painful. The letter of Sulpicius to Cicero on the loss of his daughter is ingenious. The example of David on the loss of his child is heroic. A widow lady was left in narrow circumstances with a boy and a girl, two beautiful and lively children, the one six and the other seven years of age; as her circumstances allowed her to keep but one maid-servant, these two children were the sole attention, employment, and consolation of her life; she fed them, dressed them, slept with them, and taught them herself; they were both snatched from her by the gangrenous sore throat in one week: so that she lost at once all that employed her, as well as all that was dear to her. For the first three or four days after their death, when any friend visited her, she sat upright, with her eyes wide open, without shedding tears, and affected to speak of indifferent things. Afterwards she began to weep much, and for some weeks talked to her friends of nothing else but her dear children. But did not for many years, even to her dying hour, get quite over a gloom, which was left upon her countenance. In violent grief, when tears flow, it is esteemed a good symptom; because then the actions caused by sensitive association take the place of those caused by volition; that is, they prevent the voluntary exertions of ideas, or muscular actions, which constitute insanity. The sobbing and sighing attendant upon grief are not convulsive movements, they are occasioned by the sensorial power being so expended on the painful ideas, and their connections, that the person neglects to breathe for a time, and then a violent sigh or sob is necessary to carry on the blood, which oppresses the pulmonary vessels, which is then performed by deep or quick inspirations, and laborious expirations. Sometimes nevertheless the breath is probably for a while voluntarily held, as an effort to relieve pain. The paleness and ill health occasioned by long grief is spoken of in Class IV. 2. 1. 9. The melioration of grief by time, and its being at length even attended with pleasure, depends on our retaining a distinct idea of the lost object, and forgetting for a time the idea of the loss of it. This pleasure of grief is beautifully described by Akenside. Pleasures of Imagination, Book II. l. 680. ----------Ask the faithful youth, Why the cold urn of her, whom long he loved, So often fills his arms; so often draws His lonely footsteps at the silent hour To pay the mournful tribute of his tears? Oh! he will tell thee, that the wealth of worlds Should ne'er seduce his bosom to forego That sacred hour; when, stealing from the noise Of care and envy, sweet remembrance soothes With Virtue's kindest looks his aching breast, And turns his tears to rapture. M. M. Consolation is best supplied by the Christian doctrine of a happy immortality. In the pagan religion the power of dying was the great consolation in irremediable distress. Seneca says, "no one need be unhappy unless by his own fault." And the author of Telemachus begins his work by saying, that Calypso could not console herself for the loss of Ulysses, and found herself unhappy in being immortal. In the first hours of grief the methods of consolation used by uncle Toby, in Tristram Shandy, is probably the best; "he sat down in an arm chair by the bed of his distressed friend, and said nothing." 11. _Tædium vitæ._ The inanity of sublunary things has afforded a theme to philosophers, moralists, and divines, from the earliest records of antiquity; "Vanity of vanities!" says the preacher, "all is vanity!" Nor is there any one, I suppose, who has passed the meridian of life, who has not at some moments felt the nihility of all things. Weariness of life in its moderate degree has been esteemed a motive to action by some philosophers. See Sect. XXXIV. 2. 3. But in those men, who have run through the usual amusements of life early in respect to their age; and who have not industry or ability to cultivate those sciences, which afford a perpetual fund of novelty, and of consequent entertainment, are liable to become tired of life, as they suppose there is nothing new to be found in it, that can afford them pleasure; like Alexander, who is said to have shed tears, because he had not another world to conquer. Mr. ----, a gentleman about fifty, of polished manners, who in a few months afterwards destroyed himself, said to me one day, "a ride out in the morning, and a warm parlour and a pack of cards in the afternoon, is all that life affords." He was persuaded to have an issue on the top of his head, as he complained of a dull head-ach, which being unskilfully managed, destroyed the pericranium to the size of an inch in diameter; during the time this took in healing, he was indignant about it, and endured life, but soon afterwards shot himself. Mr. ----, a gentleman of Gray's Inn, some years ago was prevailed upon by his friends to dismiss a mistress, by whom he had a child, but who was so great a termagant and scold, that she was believed to use him very ill, and even to beat him. He became melancholy in two days from the want of his usual stimulus to action, and cut his throat on the third so completely, that he died immediately. Mr. Anson, the brother to the late Lord Anson, related to me the following anecdote of the death of Lord Sc----. His Lordship sent to see Mr. Anson on the Monday preceding his death, and said, "You are the only friend I value in the world, I determined therefore to acquaint you, that I am tired of the insipidity of life, and intend to-morrow to leave it." Mr. Anson said, after much conversation, that he was obliged to leave town till Friday, and added, "As you profess a friendship for me, do me this last favour, I entreat you, live till I return." Lord Sc---- believed this to be a pious artifice to gain time, but nevertheless agreed, if he should return by four o'clock on that day. Mr. Anson did not return till five, and found, by the countenances of the domestics, that the deed was done. He went into his chamber and found the corpse of his friend leaning over the arm of a great chair, with the pistol on the ground by him, the ball of which had been discharged into the roof of his mouth, and passed into his brain. Mr. ---- and Mr. ----, two young men, heirs to considerable fortunes, shot themselves at the age of four or five and twenty, without their friends being able to conjecture any cause for those rash actions. One of them I had long known to express himself with dissatisfaction of the world; at eighteen years of age he complained, that he could not entertain himself; he tried to study the law at Cambridge, and afterwards went abroad for a year or two by my advice; but returned dissatisfied with all things. As he had had an eruption for some years on a part of his face, which he probably endeavoured to remove by external applications; I was induced to ascribe his perpetual ennui to the pain or disagreeable sensation of a diseased liver. The other young gentleman shot himself in his bed-room, and I was informed that there was found written on a scrap of paper on his table, "I am impotent, and therefore not fit to live." From whence there was reason to conclude, that this was the hallucinatio maniacalis, the delirious idea, which caused him to destroy himself. The case therefore belongs to mania mutabilis, and not to tædium vitæ. M. M. Some restraint in exhausting the usual pleasures of the world early in life. The agreeable cares of a matrimonial life. The cultivation of science, as of chemistry, natural philosophy, natural history, which supplies an inexhaustible source of pleasurable novelty, and relieves ennui by the exertions it occasions. In many of these cases, whence irksomeness of life has been the ostensible cause of suicide, there has probably existed a maniacal hallucination, a painful idea, which the patient has concealed even to his dying hour; except where the mania has evidently arisen from hereditary or acquired disease of the membranous or glandular parts of the system. 12. _Pulchritudinis desiderium._ The loss of beauty, either by disease, as by the small-pox, or by age, as life advances, is sometimes painfully felt by ladies, who have been much flattered on account of it. There is a curious case of this kind related in Le Sage's Bachelor of Salamanca, which is too nicely described to be totally imaginary. In this situation some ladies apply to what are termed cosmetics under various names, which crowd the newspapers. Of these the white has destroyed the health of thousands; a calx, or magistery, of bismuth is supposed to be sold in the shops for this purpose; but it is either, I am informed, in part or entirely white lead or cerussa. The pernicious effects of the external use of those saturnine applications are spoken of in gutta rosea, Class II. 1. 4. 6. The real calx of bismuth would probably have the same ill effect. As the red paint is prepared from cochineal, which is an animal body, less if any injury arises from its use, as it only lies on the skin like other filth. The tan of the skin occasioned by the sun may be removed by lemon juice evaporated by the fire to half its original quantity, or by diluted marine acid; which cleans the cuticle, by eroding its surface, but requires much caution in the application; the marine acid must be diluted with water, and when put upon the hand or face, after a second of time, as soon as the tan disappears, the part must be washed with a wet towel and much warm water. Freckles lie too deep for this operation, nor are they in general removeable by a blister, as I once experienced. See Class I. 2. 2. 9. It is probable, that those materials which stain silk, or ivory, might be used to stain the cuticle, or hair, permanently; as they are all animal substances. But I do not know, that any trials of this kind have been made on the skin. I endeavoured in vain to whiten the back of my hand by marine acid oxygenated by manganese, which so instantly whitens cotton. The cure therefore must be sought from moral writers, and the cultivation of the graces of the mind, which are frequently a more valuable possession than celebrated beauty. 13. _Paupertatis timor._ The fear of poverty is one kind of avarice; it is liable to affect people who have left off a profitable and active business; as they are thus deprived of their usual exertions, and are liable to observe the daily expenditure of money, without calculating the source from whence it flows. It is also liable to occur with a sudden and unexpected increase of fortune. Mr. ----, a surgeon, about fifty years of age, who was always rather of a parsimonious disposition, had a large house, with a fortune of forty thousand pounds, left him by a distant relation; and in a few weeks became insane from the fear of poverty, lamenting that he should die in a jail or workhouse. He had left off a laborious country business, and the daily perception of profit in his books; he also now saw greater expences going forwards in his new house, than he had been accustomed to observe, and did not so distinctly see the source of supply; which seems to have occasioned the maniacal hallucination.--This idea of approaching poverty is a very frequent and very painful disease, so as to have induced many to become suicides, who were in good circumstances; more perhaps than any other maniacal hallucination, except the fear of hell. The covetousness of age is more liable to affect single men, than those who have families; though an accumulation of wealth would seem to be more desirable to the latter. But an old man in the former situation, has no personal connections to induce him to open his purse; and having lost the friends of his youth, and not easily acquiring new ones, feels himself alone in the world; feels himself unprotected, as his strength declines, and is thus led to depend for assistance on money, and on that account wishes to accumulate it. Whereas the father of a family has not only those connections, which demand the frequent expenditure of money, but feels a consolation in the friendship of his children, when age may render their good offices necessary to him. M. M. I have been well informed of a medical person in good circumstances in London, who always carries an account of his affairs, as debtor and creditor, in his pocket-book; and looks over it frequently in a day, when this disease returns upon him; and thus, by counteracting the maniacal hallucination, wisely prevents the increase of his insanity. Another medical person, in London, is said to have cured himself of this disease by studying mathematics with great attention; which exertions of the mind relieved the pain of the maniacal hallucination. Many moral writers have stigmatised this insanity; the covetous, they say, commit crimes and mortify themselves without hopes of reward; and thus become miserable both in this world and the next. Thus Juvenal: Cum furor haud dubius, cum sit manifesta phrenitis, Ut locuples moriaris, egenti vivere fato! The covetous man thought he gave good advice to the spendthrift, when he said, "Live like me," who well answered him, ----------"Like you, Sir John? "That I can do, when all I have is gone!" POPE. 14. _Lethi timor._ The fear of death perpetually employs the thoughts of these patients; hence they are devising new medicines, and applying to physicians and quacks without number. It is confounded with hypochondriasis, Class I. 2. 4. 10. in popular conversation, but is in reality an insanity. A young gentleman, whom I advised to go abroad as a cure for this disease, assured me, that during the three years he was in Italy and France he never passed a quarter of an hour without fearing he should die. But has now for above twenty years experienced the contrary. The sufferers under this malady are generally at once discoverable by their telling you, amidst an unconnected description of their complaints, that they are nevertheless not afraid of dying. They are also easily led to complain of pains in almost any part of the body, and are thus soon discovered. M. M. As the maniacal hallucination has generally arisen in early infancy from some dreadful account of the struggles and pain of dying, I have sometimes observed, that these patients have received great consolation from the instances I have related to them of people dying without pain. Some of these, which I think curious, I shall concisely relate, as a part of the method of cure. Mr. ----, an elderly gentleman, had sent for me one whole day before I could attend him; on my arrival he said he was glad to see me, but that he was now quite well, except that he was weak, but had had a pain in his bowels the day before. He then lay in bed with his legs cold up to the knees, his hands and arms cold, and his pulse scarcely discernible, and died in about six hours. Mr. ----, another gentleman about sixty, lay in the act of dying, with difficult respiration like groaning, but in a kind of stupor or coma vigil, and every ten or twelve minutes, while I sat by him, he waked, looked up, and said, "who is it groans so, I am sure there is somebody dying in the room," and then sunk again into a kind of sleep. From these two cases there appeared to be no pain in the act of dying, which may afford consolation to all, but particularly to those who are afflicted with the fear of death. 15. _Orci timor._ The fear of hell. Many theatric preachers among the Methodists successfully inspire this terror, and live comfortably upon the folly of their hearers. In this kind of madness the poor patients frequently commit suicide; although they believe they run headlong into the hell, which they dread! Such is the power of oratory, and such the debility of the human understanding! Those, who suffer under this insanity, are generally the most innocent and harmless people; who are then liable to accuse themselves of the greatest imaginary crimes, and have so much intellectual cowardice, that they dare not reason about those things, which they are directed by their priests to believe, however contradictory to human apprehension, or derogatory to the great Creator of all things. The maniacal hallucination at length becomes so painful, that the poor insane flies from life to become free from it. M. M. Where the intellectual cowardice is great, the voice of reason is ineffectual; but that of ridicule may save many from those mad-making doctors; though it is too weak to cure those, who are already hallucinated. Foot's Farces are recommended for this purpose. 16. _Satyriasis._ An ungovernable desire of venereal indulgence. The remote cause is probably the stimulus of the semen; whence the phallus becomes distended with blood by the arterial propulsion of it being more strongly excited than the correspondent venous absorption. At the same time a new sense is produced in the other termination of the urethra; which, like itching, requires some exterior friction to facilitate the removal of the cause of the maniacal actions, which may probably be increased in those cases by some associated hallucinations of ideas. It differs from priapismus chronicus in the desire of its appropriated object, which is not experienced in the latter, Class I. 1. 4. 6. and from the priapismus amatorius, Class II. 1. 7. 9. in the maniacal actions in consequence of desire. The furor uterius, or nymphomania, is a similar disease. M. M. Venesection. Cathartics. Torpentia. Marriage. 17. _Ira._ Anger is caused by the pain of offended pride. We are not angry at breaking a bone, but become quite insane from the smallest stroke of a whip from an inferior. Ira furor brevis. Anger is not only itself a temporary madness, but is a frequent attendant on other insanities, and as, whenever it appears, it distinguishes insanity from delirium, it is generally a good sign in fevers with debility. An injury voluntarily inflicted on us by others excites our exertions of self-defence or of revenge against the perpetrator of it; but anger does not succeed in any great degree unless our pride is offended; this idea is the maniacal hallucination, the pain of which sometimes produces such violent and general exertions of our muscles and ideas, as to disappoint the revenge we meditate, and vainly to exhaust our sensorial power. Hence angry people, if not further excited by disagreeable language, are liable in an hour or two to become humble, and sorry for their violence, and willing to make greater concessions than required. M. M. Be silent, when you feel yourself angry. Never use loud oaths, violent upbraidings, or strong expressions of countenance, or gesticulations of the arms, or clenched fists; as these by their former associations with anger will contribute to increase it. I have been told of a sergeant or corporal, who began moderately to cane his soldiers, when they were awkward in their exercise, but being addicted to swearing and coarse language, he used soon to enrage himself by his own expressions of anger, till toward the end he was liable to beat the delinquents unmercifully. 18. _Rabies._ Rage. A desire of biting others, most frequently attendant on canine madness. Animals in great pain, as in the colica saturnina, are said to bite the ground they lie upon, and even their own flesh. I have seen patients bite the attendants, and even their own arms, in the epilepsia dolorifica. It seems to be an exertion to relieve pain, as explained in Sect. XXXIV. 1. 3. The dread of water in hydrophobia is occasioned by the repeated painful attempts to swallow it, and is therefore not an essential or original part of the disease called canine madness. See Class III. 1. 1. 15. There is a mania reported to exist in some parts of the east, in which a man is said to run a muck; and these furious maniacs are believed to have induced their calamity by unlucky gaming, and afterwards by taking large quantities of opium; whence the pain of despair is joined with the energy of drunkenness; they are then said to sally forth into the most populous streets, and to wound and slay all they meet, till they receive their own death, which they desire to procure without the greater guilt, as they suppose, of suicide. M. M. When there appears a tendency to bite in the painful epilepsy, the end of a rolled-up towel, or a wedge of soft wood, should be put into the mouth of the patient. As a bullet is said sometimes to be given to a soldier, who is to be severely flogged, that he may by biting it better bear his punishment. 19. _Citta._ A desire to swallow indigestible substances. I once saw a young lady, about ten years of age, who filled her stomach with the earth out of a flower-pot, and vomited it up with small stones, bits of wood, and wings of infects amongst it. She had the bombycinous complexion, and looked like a chlorotic patient, though so young; this generally proceeds from an acid in the stomach. M. M. A vomit. Magnesia alba. Armenian bole. Rhubarb. Bark. Steel. A blister. See Class I. 2. 4. 5. 20. _Cacositia._ Aversion to food. This may arise, without disease of the stomach, from connecting nauseous ideas to our usual food, as by calling a ham a hog's a----. This madness is much inculcated by the stoic philosophy. See Antoninus' Meditations. See two cases of patients who refused to take nourishment, Class III. 1. 2. 1. Aversions to peculiar kinds of food are thus formed early in life by association of some maniacal hallucination with them. I remember a child, who on tasting the gristle of sturgeon, asked what gristle was? And being told it was like the division of a man's nose, received an ideal hallucination; and for twenty years afterwards could not be persuaded to taste sturgeon. The great fear or aversion, which some people experience at the sight of spiders, toads, crickets, and the like, have generally had a similar origin. M. M. Associate agreeable ideas with those which disgust; as call a spider ingenious, a frog clean and innocent; and repress all expressions of disgust by the countenance, as such expressions contribute to preserve, or even to increase, the energy of the ideas associated with them; as mentioned above in Species 17. Ira. 21. _Syphilis imaginaria._ The fear that they are infested with the venereal disease, when they have only deserved it, is a very common insanity amongst modest young men; and is not to be cured without applying artfully to the mind; a little mercury must be given, and hopes of a cure added weekly and gradually by interview or correspondence for six or eight weeks. Many of these patients have been repeatedly salivated without curing the mind! 22. _Psora imaginaria._ I have twice seen an imaginary itch, and twice an imaginary diabætes, where there was not the least vestige of either of those diseases, and once an imaginary deafness, where the patient heard perfectly well. In all these cases the hallucinated idea is so powerfully excited, that it is not to be changed suddenly by occular sensation, or reason. Yet great perseverance in the frequently presenting contrary ideas will sometimes slowly remove this hallucination, or in great length of time oblivion, or forgetfulness, performs a cure, by other means in vain attempted. 23. _Tabes imaginaria._ This imaginary disease, or hallucination, is caused by the supposed too great frequency of parting with the semen, and had long imposed upon the physician as well as the patient, till Mr. John Hunter first endeavoured to shew, that in general the morbid effects of this pollution was in the imagination; and that those were only liable to those effects in general, who had been terrified by the villainous books, which pretend to prevent or to cure it, but which were purposely written to vend some quack medicine. Most of those unhappy patients, whom I have seen, had evidently great impression of fear and self-condemnation on their minds, and might be led to make contradictory complaints in almost any part of the body, and if their confessions could be depended on, had not used this pollution to any great excess. M. M. 1. Assure them if the loss of the semen happens but twice a week, it will not injure them. 2. Marry them. The last is a certain cure; whether the disease be real or imaginary. Cold partial bath, and astringent medicines frequently taken, only recal the mind to the disease, or to the delinquency; and thence increase the imaginary effects and the real cause, if such exists. Mr. ---- destroyed himself to get free from the pain of fear of the supposed ill consequences of self-pollution, without any other apparent disease; whose parents I had in vain advised to marry him, if possible. 24. _Sympathia aliena._ Pity. Our sympathy with the pleasures and pains of others distinguishes men from other animals; and is probably the foundation of what is termed our moral sense and the source of all our virtues. See Sect. XXII. 3. 3. When our sympathy with those miseries of mankind, which we cannot alleviate, rises to excess, the mind becomes its own tormentor; and we add to the aggregate sum of human misery, which we ought to labour to diminish; as in the following eloquent lamentation from Akenside's Pleasures of Imagination, Book II. 1. 200. ----------------Dark, As midnight storms, the scene of human things Appear'd before me; deserts, burning sands, Where the parch'd adder dies; the frozen south; And desolation blasting all the west With rapine and with murder. Tyrant power Here sits enthroned in blood; the baleful charms Of superstition there infect the skies, And turn the sun to horror. Gracious Heaven! What is the life of man? Or cannot these, Not these portents thy awful will suffice? That, propagated thus beyond their scope, They rise to act their cruelties anew In my afflicted bosom, thus decreed The universal sensitive of pain, The wretched heir of evils not its own! A poet of antiquity, whose name I do not recollect, is said to have written a book describing the miseries of the world, and to have destroyed himself at the conclusion of his task. This sympathy, with all sensitive beings, has been carried so far by some individuals, and even by whole tribes, as the Gentoos, as not only to restrain them from killing animals for their support, but even to induce them to permit insects to prey upon their bodies. Such is however the condition of mortality, that the first law of nature is, "Eat or be eaten." We cannot long exist without the destruction of other animal or vegetable beings, either in their mature or their embryon state. Unless the fruits, which surround the seeds of some vegetables, or the honey stolen from them by the bee, may be said to be an exception to this assertion. See Botanic Garden, P. I. Cant. I. l. 278. Note. Hence, from the necessity of our nature, we may be supposed to have a right to kill those creatures, which we want to eat, or which want to eat us. But to destroy even insects wantonly shews an unreflecting mind or a depraved heart. Nevertheless mankind may be well divided into the selfish and the social; that is, into those whose pleasures arise from gratifying their appetites, and those whose pleasures arise from their sympathizing with others. And according to the prevalence of these opposing propensities we value or dislike the possessor of them. In conducting the education of young people, it is a nice matter to inspire them with so much benevolent sympathy, or compassion, as may render them good and amiable; and yet not so much as to make them unhappy at the sight of incurable distress. We should endeavour to make them alive to sympathize with all remediable evils, and at the same time to arm them with fortitude to bear the sight of such irremediable evils, as the accidents of life must frequently present before their eyes. About this I have treated more at large in a plan for the conduct of a boarding school for ladies, which I intend to publish in the course of the next year. 25. _Educatio heroica._ From the kinds and degrees of insanities already enumerated, the reader will probably recollect many more from his own observation; he will perceive that all extraordinary exertions of voluntary action in consequence of some false idea or hallucination, which strongly affects us, may philosophically, though not popularly, be termed an insanity; he will then be liable to divide these voluntary exertions into disagreeable, pernicious, detestable, or into meritorious, delectable, and even amiable, insanities. And will lastly be induced to conceive, that a good education consists in the art of producing such happy hallucinations of ideas, as may be followed by such voluntary exertions, as may be termed meritorious or amiable insanities. The old man of the mountain in Syria, who governed a small nation of people called Assassines, is recorded thus to have educated those of his army who were designed to assassinate the princes with whom he was at war. A young man of natural activity was chosen for the purpose, and thrown into a deep sleep by opium mixed with his food; he was then carried into a garden made to represent the paradise of Mahomet, with flowers of great beauty and fragrance, fruits of delicious flavor, and beautiful houries beckoning him into the shades. After a while, on being a second time stupified with opium, the young enthusiast was reconveyed to his apartment; and on the next day was assured by a priest, that he was designed for some great exploit, and that by obeying the commands of their prince, immortal happiness awaited him. Hence it is easy to collect how the first impressions made on us by accidental circumstances in our infancy continue through life to bias our affections, or mislead our judgments. One of my acquaintance can trace the origin of his own energies of action from some such remote sources; which justifies the observation of M. Rousseau, that the seeds of future virtues or vices are oftener sown by the mother, than the tutor. * * * * * ORDO II. _Decreased Volition._ GENUS I. _With decreased Actions of the Muscles._ Our muscles become fatigued by long contraction, and cease for a time to be excitable by the will; owing to exhaustion of the sensorial power, which resides in them. After a short interval of relaxation the muscle regains its power of voluntary contraction; which is probably occasioned by a new supply of the spirit of animation. In weaker people these contractions cease sooner, and therefore recur more frequently, and are attended with shorter intervals of relaxation, as exemplified in the quickness of the pulse in fevers with debility, and in the tremors of the hands of aged or feeble people. After a common degree of exhaustion of the sensorial power in a muscle, it becomes again gradually restored by the rest of the muscle; and even accumulated in those muscles, which are most frequently used; as in those which constitute the capillaries of the skin after having been rendered torpid by cold. But in those muscles, which are generally obedient to volition, as those of locomotion, though their usual quantity of sensorial power is restored by their quiescence, or in sleep (for sleep affects these parts of the system only), yet but little accumulation of it succeeds. And this want of accumulation of the sensorial power in these muscles, which are chiefly subservient to volition, explains to us one cause of their greater tendency to paralytic affection. It must be observed, that those parts of the system, which have been for a time quiescent from want of stimulus, as the vessels of the skin, when exposed to cold, acquire an accumulation of sensorial power during their inactivity; but this does not happen at all, or in much less quantity, from their quiescence after great expenditure of sensorial power by a previous excessive stimulus, as after intoxication. In this case the muscles or organs of sense gradually acquire their natural quantity of sensorial power, as after sleep; but not an accumulation or superabundance of it. And by frequent repetitions of exhaustion by great stimulus, these vessels cease to acquire their whole natural quantity of sensorial power; as in the schirrous stomach, and schirrous liver, occasioned by the great and frequent stimulus of vinous spirit; which may properly be termed irritative paralysis of those parts of the system. In the same manner in common palsies the inaction of the paralytic muscle seems not to be owing to defect of the stimulus of the will, but to exhaustion of sensorial power. Whence it frequently follows great exertion, as in Sect. XXXIV. 1. 7. Thus some parts of the system may cease to obey the will, as in common paralysis; others may cease to be obedient to sensation, as in the impotency of age; others to irritation, as in schirrous viscera; and others to association, as in impediment of speech; yet though all these may become inexcitable, or dead, in respect to that kind of stimulus, which has previously exhausted them, whether of volition, or sensation, or irritation, or association, they may still in many cases be excited by the others. SPECIES. 1. _Lassitudo._ Fatigue or weariness after much voluntary exertion. From the too great expenditure of sensorial power the muscles are with difficulty brought again into voluntary contraction; and seem to require a greater quantity or energy of volition for this purpose. At the same time they still remain obedient to the stimulus of agreeable sensation, as appears in tired dancers finding a renovation of their aptitude to motion on the acquisition of an agreeable partner; or from a tired child riding on a gold-headed cane, as in Sect. XXXIV. 2. 6. These muscles are likewise still obedient to the sensorial power of association, because the motions, when thus excited, are performed in their designed directions, and are not broken into variety of gesticulation, as in St. Vitus's dance. A lassitude likewise frequently occurs with yawning at the beginning of ague-fits; where the production of sensorial power in the brain is less than its expenditure. For in this case the torpor may either originate in the brain, or the torpor of some distant parts of the system may by sympathy affect the brain, though in a less proportionate degree than the parts primarily affected. 2. _Vacillatio senilis._ Some elderly people acquire a see-saw motion of their bodies from one side to the other, as they sit, like the oscillation of a pendulum. By these motions the muscles, which preserve the perpendicularity of the body, are alternately quiescent, and exerted; and are thus less liable to fatigue or exhaustion. This therefore resembles the tremors of old people above mentioned, and not those spasmodic movements of the face or limbs, which are called tricks, described in Class IV. 1. 3. 2. which originate from excess of sensorial power, or from efforts to relieve disagreeable sensation, and are afterwards continued by habit. 3. _Tremor senilis._ Tremor of old age consists of a perpetual trembling of the hands, or of the head, or of other muscles, when they are exerted; and is erroneously called paralytic; and seems owing to the small quantity of animal power residing in the muscular fibres. These tremors only exist when the affected muscles are excited into action, as in lifting a glass to the mouth, or in writing, or in keeping the body upright; and cease again, when no voluntary exertion is attempted, as in lying down. Hence these tremors evidently originate from the too quick exhaustion of the lessened quantity of the spirit of animation. So many people tremble from fear or anger, when too great a part of the sensorial power is exerted on the organs of sense, so as to deprive the muscles, which support the body erect, of their due quantity. 4. _Brachiorum paralysis._ A numbness of the arms is a frequent symptom in hydrops thoracis, as explained in Class I. 2. 3. 14. and in Sect. XXIX. 5. 2.; it also accompanies the asthma dolorificum, Class III. 1. 1. 11. and is owing probably to the same cause in both. In the colica saturnina a paralysis affects the wrists, as appears on the patient extending his arm horizontally with the palm downwards, and is often attended with a tumor on the carpal or metacarpal bones. See Class IV. 1. 2. 10. Mr. M----, a miner and well-sinker, about three years ago, lost the power of contracting both his thumbs; the balls or muscles of the thumbs are much emaciated, and remain paralytic. He ascribes his disease to immersing his hands too long in cold water in the execution of his business. He says his hands had frequently been much benumbed before, so that he could not without difficulty clench them; but that they recovered their motion, as soon as they began to glow, after he had dried and covered them. In this case there existed two injurious circumstances of different kinds; one the violent and continued action of the muscles, which destroys by exhausting the sensorial power; and the other, the application of cold, which destroys by defect of stimulus. The cold seems to have contributed to the paralysis by its long application, as well as the continued exertion; but as during the torpor occasioned by the exposure to cold, if the degree of it be not so great as to extinguish life, the sensorial power becomes accumulated; there is reason to believe, that the exposing a paralytic limb to the cold for a certain time, as by covering it with snow or iced water for a few minutes, and then covering it with warm flannel, and this frequently repeated, might, by accumulation of sensorial power, contribute to restore it to a state of voluntary excitability. As this accumulation of sensorial power, and consequent glow, seems, in the present case, several times to have contributed to restore the numbness or inability of those muscles, which at length became paralytic. See Class I. 2. 3. 21. M. M. Ether externally. Friction. Saline warm bath. Electricity. 5. _Raucedo paralytica._ Paralytic hoarseness consists in the almost total loss of voice, which sometimes continues for months, or even years, and is occasioned by inability or paralysis of the recurrent nerves, which serve the muscles of vocality, by opening or closing the larynx. The voice generally returns suddenly, even so as to alarm the patient. A young lady, who had many months been affected with almost a total loss of voice, and had in vain tried variety of advice, recovered her voice in an instant, on some alarm as she was dancing at an assembly. Was this owing to a greater exertion of volition than usual? like the dumb young man, the son of Croesus, who is related to have cried out, when he saw his father's life endangered by the sword of his enemy, and to have continued to speak ever afterwards. Two young ladies in this complaint seemed to be cured by electric shocks passed through the larynx every day for a fortnight. See Raucedo catarrhalis, Class II. 1. 3. 5. M. M. An emetic. Electric shocks. Mustard-seed, a large spoonful swallowed whole, or a little bruised, every morning. Valerian. Burnt sponge. Blisters on each side of the larynx. Sea-bathing. A gargle of decoction of seneca. Friction. Frequent endeavours to shout and sing. 6. _Vesicæ urinariæ paralysis._ Paralysis of the bladder is frequently a symptom in inirritative fever; in this case the patient makes no water for a day or two; and the tumor of the bladder distended with urine may be seen by the shape of the abdomen, as if girt by a cord below the navel, or distinguished by the hand. Many patients in this situation make no complaint, and suffer great injury by the inattention of their attendants; the water must be drawn off once or twice a day by means of a catheter, and the region of the bladder gently pressed by the hand, whilst the patient be kept in a sitting or erect posture. M. M. Bark. Wine. Opium, a quarter of a grain every six hours. Balsam of copaiva or of Peru. Tincture of cantharides 20 drops twice a day, or repeated small blisters. 7. _Recti paralysis._ Palsy of the rectum. The rectum intestinum, like the urinary bladder in the preceding article, possesses voluntary power of motion; though these volitions are at times uncontrollable by the will, when the acrimony of the contained feces, or their bulk, stimulate it to a greater degree. Hence it happens, that this part is liable to lose its voluntary power by paralysis, but is still liable to be stimulated into action by the contained feces. This frequently occurs in fevers, and is a bad sign as a symptom of general debility; and it is the sensibility of the muscular fibres of this and of the urinary bladder remaining, after the voluntarity has ceased, which occasions these two reservoirs so soon to regain, as the fever ceases, their obedience to volition; because the paralysis is thus shewn to be less complete in those cases than in common hemiplegia; as in the latter the sense of touch, though perhaps not the sense of pain, is generally destroyed in the paralytic limb. M. M. A sponge introduced within the sphincter ani to prevent the constant discharge, which should have a string put through it, by which it may be retracted. 8. _Paresis voluntaria._ Indolence; or inaptitude to voluntary action. This debility of the exertion of voluntary efforts prevents the accomplishment of all great events in life. It often originates from a mistaken education, in which pleasure or flattery is made the immediate motive of action, and not future advantage; or what is termed duty. This observation is of great value to those, who attend to the education of their own children. I have seen one or two young married ladies of fortune, who perpetually became uneasy, and believed themselves ill, a week after their arrival in the country, and continued so uniformly during their stay; yet on their return to London or Bath immediately lost all their complaints, and this repeatedly; which I was led to ascribe to their being in their infancy surrounded with menial attendants, who had flattered them into the exertions they then used. And that in their riper years, they became torpid for want of this stimulus, and could not amuse themselves by any voluntary employment; but required ever after, either to be amused by other people, or to be flattered into activity. This I suppose, in the other sex, to have supplied one source of ennui and suicide. 9. _Catalepsis_ is sometimes used for fixed spasmodic contractions or tetanus, as described in Sect. XXXIV. 1. 5. and in Class III. 1. 1. 13. but is properly simply an inaptitude to muscular motion, the limbs remaining in any attitude in which they are placed. One patient, whom I saw in this situation, had taken much mercury, and appeared universally torpid. He sat in a chair in any posture he was put, and held a glass to his mouth for many minutes without attempting to drink, or withdrawing his hand. He never spoke, and it was at first necessary to compel him to drink broth; he recovered in a few weeks without relapse. 10. _Hemiplegia._ Palsy of one side consists in the total disobedience of the affected muscles to the power of volition. As the voluntary motions are not perpetually exerted, there is little sensorial power accumulated during their quiescence, whence they are less liable to recover from torpor, and are thus more frequently left paralytic, or disobedient to the power of volition, though they are sometimes still alive to painful sensation, as to the prick of a pin, and to heat; also to irritation, as in stretching and yawning; or to electric shocks. Where the paralysis is complete the patient seems gradually to learn to use his limbs over again by repeated efforts, as in infancy; and, as time is required for this purpose, it becomes difficult to know, whether the cure is owing to the effect of medicines, or to the repeated efforts of the voluntary power. The dispute, whether the nerves decussate or cross each other before they leave the cavities of the skull or spine, seems to be decided in the affirmative by comparative anatomy; as the optic nerves of some fish have been shewn evidently to cross each other; as seen by Haller, Elem. Physiol. t. v. p. 349. Hence the application of blisters, or of ether, or of warm fomentations, should be on the side of the head opposite to that of the affected muscles. This subject should nevertheless be nicely determined, before any one should trepan for the hydrocephalus internus, when the disease is shewn to exist only on one side of the brain, by a squinting affecting but one eye; as proposed in Class I. 2. 5. 4. Dr. Sommering has shewn, that a true decussation of the optic nerves in the human subject actually exists, Elem. of Physiology by Blumenbach, translated by C. Caldwell, Philadelphia. This further appears probable from the oblique direction and insertion of each optic nerve, into the side of the eye next to the nose, in a direct line from the opposite side of the brain. The vomiting, which generally attends the attack of hemiplegia, is mentioned in Sect. XX. 8. and is similar to that attending vertigo in sea-sickness, and at the commencement of some fevers. Black stools sometimes attend the commencement of hemiplegia, which is probably an effusion of blood from the biliary duct, where the liver is previously affected; or some blood may be derived to the intestines by its escaping from the vena cava into the receptacle of chyle during the distress of the paralytic attack; and may be conveyed from thence into the intestines by the retrograde motions of the lacteals; as probably sometimes happens in diabætes. See Sect. XXVII. 2. Palsy of one side of the face is mentioned in Class II. 1. 4. 6. Paralysis of the lacteals, of the liver, and of the veins, which are described in Sect. XXVIII. XXX. and XXVII. do not belong to this class, as they are not diseases of voluntary motions. M. M. The electric sparks and shocks, if used early in the disease, are frequently of service. A purge of aloes, or calomel. A vomit. Blister. Saline draughts. Then the bark. Mercurial ointment or sublimate, where the liver is evidently diseased; or where the gutta rosea has previously existed. Sudden alarm. Frequent voluntary efforts. Externally ether. Volatile alcali. Fomentation on the head. Friction. When children, who have suffered an hemiplegia, begin to use the affected arm, the other hand should be tied up for half an hour three or four times a day; which obliges them at their play to use more frequent voluntary efforts with the diseased limb, and thus sooner to restore the dissevered associations of motion. Dr. J. Alderson has lately much recommended the leaves of rhus toxicodendon (sumach), from one gr. to iv. of the dried powder to be taken three or four times a day. Essay on Rhus Toxic. Johnson, London, 1793. But it is difficult to know what medicine is of service, as the movements of the muscles must be learned, as in infancy, by frequent efforts. 11. _Paraplegia._ A palsy of the lower half of the body divided horizontally. Animals may be conceived to have double bodies, one half in general resembling so exactly the other, and being supplied with separate sets of nerves; this gives rise to hemiplegia, or palsy of one half of the body divided vertically; but the paraplegia, or palsy of the lower parts of the system, depends on an injury of the spinal marrow, or that part of the brain which is contained in the vertebræ of the back; by which all the nerves situated below the injured part are deprived of their nutriment, or precluded from doing their proper offices; and the muscles, to which they are derived, are in consequence disobedient to the power of volition. This sometimes occurs from an external injury, as a fall from an eminence; of which I saw a deplorable instance, where the bladder and rectum, as well as the lower limbs, were deprived of so much of their powers of motion, as depended on volition or sensation; but I suppose not of that part of it, which depends on irritation. In the same manner as the voluntary muscles in hemiplegia are sometimes brought into action by irritation, as in stretching or pendiculation, described in Sect. VII. 1. 3. But the most frequent cause of paraplegia is from a protuberance of one of the spinal vertebræ; which is owing to the innutrition or softness of bones, described in Class I. 2. 2. 17. The cure of this deplorable disease is frequently effected by the stimulus of an issue placed on each side of the prominent spine, as first published by Mr. Pott. The other means recommended in softness of bones should also be attended to; both in respect to the internal medicines, and to the mechanical methods of supporting, or extending the spine; which last, however, in this case requires particular caution. 12. _Somnus._ In sleep all voluntary power is suspended, see Sect. XVIII. An unusual quantity of sleep is often produced by weakness. In this case small doses of opium, wine, and bark, may be given with advantage. For the periods of sleep, see Class IV. 2. 4. 1. The subsequent ingenious observations on the frequency of the pulse, which sometimes occurs in sleep, are copied from a letter of Dr. Currie of Liverpool to the author. "Though rest in general perhaps renders the healthy pulse slower, yet under certain circumstances the contrary is the truth. A full meal without wine or other strong liquor does not increase the frequency of my pulse, while I sit upright, and have my attention engaged. But if I take a recumbent posture after eating, my pulse becomes more frequent, especially if my mind be vacant, and I become drowsy; and, if I slumber, this increased frequency is more considerable with heat and flushing. "This I apprehend to be a general truth. The observation may be frequently made upon children; and the restless and feverish nights experienced by many people after a full supper are, I believe, owing to this cause. The supper occasions no inconvenience, whilst the person is upright and awake; but, when he lies down and begins to sleep, especially if he does not perspire, the symptoms above mentioned occur. Which may be thus explained in part from your principles. When the power of volition is abolished, the other sensorial actions are increased. In ordinary sleep this does not occasion increased frequency of the pulse; but where sleep takes place during the process of digestion, the digestion itself goes on with increased rapidity. Heat is excited in the system faster than it is expended; and operating on the sensitive actions, it carries them beyond the limitation of pleasure, producing, as is common in such cases, increased frequency of pulse. "It is to be observed, that in speaking of the heat generated under these circumstances, I do not allude to any chemical evolution of heat from the food in the process of digestion. I doubt if this takes place to any considerable degree, for I do not observe that the parts incumbent on the stomach are increased in heat during the most hurried digestion. It is on some parts of the surface, but more particularly on the extremities of the body, that the increased heat excited by digestion appears, and the heat thus produced arises, as it should seem, from the sympathy between the stomach and the vessels of the skin. The parts most affected are the palms of the hands and the soles of the feet. Even there the thermometer seldom rises above 97 or 98 degrees, a temperature not higher than that of the trunk of the body; but three or four degrees higher than the common temperature of these parts, and therefore producing an uneasy sensation of heat, a sensation increased by the great sensibility of the parts affected. "That the increased heat excited by digestion in sleep is the cause of the accompanying fever, seems to be confirmed by observing, that if an increased expenditure of heat accompanies the increased generation of it (as when perspiration on the extremities or surface attends this kind of sleep) the frequent pulse and flushed countenance do not occur, as I know by experiment. If, during the feverish sleep already mentioned, I am awakened, and my attention engaged powerfully, my pulse becomes almost immediately slower, and the fever gradually subsides." From these observations of Dr. Currie it appears, that, while in common sleep the actions of the heart, arteries, and capillaries, are strengthened by the accumulation of sensorial power during the suspension of voluntary action, and the pulse in consequence becomes fuller and slower; in the feverish sleep above described the actions of the heart, arteries, and capillaries, are quickened as well as strengthened by their consent with the increased actions of the stomach, as well as by the stimulus of the new chyle introduced into the circulation. For the stomach, and all other parts of the system, being more sensible and more irritable during sleep, Sect. XVIII. 15. and probably more ready to act from association, are now exerted with greater velocity as well as strength, constituting a temporary fever of the sensitive irritated kind, resembling the fever excited by wine in the beginning of intoxication; or in some people by a full meal in their waking hours. Sect. XXXV. 1. On waking, this increased sensibility and irritability of the system ceases by the renewed exertions of volition; in the same manner as more violent exertions of volition destroy greater pains; and the pulse in consequence subsides along with the increase of heat; if more violent efforts of volition are exerted, the system becomes still less affected by sensation or irritation. Hence the fever and vertigo of intoxication are lessened by intense thinking, Sect. XXI. 8; and insane people are known to bear the pain of cold and hunger better than others, Sect. XXXIV. 2. 5; and lastly, if greater voluntary efforts exist, as in violent anger or violent exercise, the whole system is thrown into more energetic action, and a voluntary fever is induced, as appears by the red skin, quickened pulse, and increase of heat; whence dropsies and fevers with debility are not unfrequently removed by insanity. Hence the exertion of the voluntary power in its natural degree diminishes the increased sensibility, and irritability, and probably the increased associability, which occurs during sleep; and thus reduces the frequency of the pulse in the feverish sleep after a full meal. In its more powerful state of exertion, it diminishes or destroys sensations and irritations, which are stronger than natural, as in intoxication, or which precede convulsions, or insanity. In its still more powerful degree, the superabundance of this sensorial power actuates and invigorates the whole moving system, giving strength and frequency to the pulse, and an universal glow both of colour and of heat, as in violent anger, or outrageous insanities. If, in the feverish sleep above described, the skin becomes cooled by the evaporation of much perspirable matter, or by the application of cooler air, or thinner clothes, the actions of the cutaneous capillaries are lessened by defect of the stimulus of heat, which counteracts the increase of sensibility during sleep, and the pulsations of the heart and arteries become slower from the lessened stimulus of the particles of blood thus cooled in the cutaneous and pulmonary vessels. Hence the admission of cold air, or ablution with subtepid or with cold water, in fevers with hot skin, whether they be attended with arterial strength, or arterial debility, renders the pulse slower; in the former case by diminishing the stimulus of the blood, and in the latter by lessening the expenditure of sensorial power. See Suppl. I. 8. and 15. 13. _Incubus._ The night-mare is an imperfect sleep, where the desire of locomotion is vehement, but the muscles do not obey the will; it is attended with great uneasiness, a sense of suffocation, and frequently with fear. It is caused by violent fatigue, or drunkenness, or indigestible food, or lying on the back, or perhaps from many other kinds of uneasiness in our sleep, which may originate either from the body or mind. Now as the action of respiration is partly voluntary, this complaint may be owing to the irritability of the system being too small to carry on the circulation of the blood through the lungs during sleep, when the voluntary power is suspended. Whence the blood may accumulate in them, and a painful oppression supervene; as in some hæmorrhages of the lungs, which occur during sleep; and in patients much debilitated by fevers. See Somnus interruptus, Class I. 2. 1. 3. and I. 2. 1. 9. Great fatigue with a full supper and much wine, I have been well informed by one patient, always produced this disease in himself to a great degree. Now the general irritability of the system is much decreased by fatigue, as it exhausts the sensorial power; and secondly, too much wine and stimulating food will again diminish the irritability of some parts of the system, by employing a part of the sensorial power, which is already too small, in digesting a great quantity of aliment; and in increasing the motions of the organs of sense in consequence of some degree of intoxication, whence difficulty of breathing may occur from the inirritability of the lungs, as in Class I. 2. 1. 3. M. M. To sleep on a hard bed with the head raised. Moderate supper. The bark. By sleeping on a harder bed the patient will turn himself more frequently, and not be liable to sleep too profoundly, or lie too long in one posture. To be awakened frequently by an alarm clock. 14. _Lethargus._ The lethargy is a slighter apoplexy. It is supposed to originate from universal pressure on the brain, and is said to be produced by compressing the spinal marrow, where there is a deficiency of the bone in the spina bifida. See Sect. XVIII. 20. Whereas in the hydrocephalus there is only a partial pressure of the brain; and probably in nervous fevers with stupor the pressure on the brain may affect only the nerves of the senses, which lie within the skull, and not those nerves of the medulla oblongata, which principally contribute to move the heart and arteries; whence in the lethargic or apoplectic stupor the pulse is slow as in sleep, whereas in nervous fever the pulse is very quick and feeble, and generally so in hydrocephalus. In cases of obstructed kidneys, whether owing to the tubuli uriniferi being totally obstructed by calculous matter, or by their paralysis, a kind of drowsiness or lethargy comes on about the eighth or ninth day, and the patient gradually sinks. See Class I. 1. 3. 9. 15. _Syncope epileptica_, is a temporary apoplexy, the pulse continuing in its natural state, and the voluntary power suspended. This terminates the paroxysms of epilepsy. When the animal power is much exhausted by the preceding convulsions, so that the motions from sensation as well as those from volition are suspended; in a quarter or half an hour the sensorial power becomes restored, and if no pain, or irritation producing pain, recurs, the fit of epilepsy ceases; if the pain recurs, or the irritation, which used to produce it, a new fit of convulsion takes place, and is succeeded again by a syncope. See Epilepsy, Class III. 1. 1. 7. 16. _Apoplexia._ Apoplexy may be termed an universal palsy, or a permanent sleep. In which, where the pulse is weak, copious bleeding must be injurious; as is well observed by Dr. Heberden, Trans. of the College. Mr. ----, about 70 years of age, had an apoplectic seizure. His pulse was strong and full. One of the temporal arteries was opened, and about ten ounces of blood suddenly taken from it. He seemed to receive no benefit from this operation; but gradually sunk, and lived but a day or two. If apoplexy arises from the pressure of blood extravasated on the brain, one moderate venesection may be of service to prevent the further effusion of blood; but copious venesection must be injurious by weakening the patient; since the effused blood must have time, as in common vibices or bruises, to undergo a chemico-animal process, so to change its nature as to fit it for absorption; which may take two or three weeks, which time a patient weakened by repeated venesection or arteriotomy may not survive. Mrs. ----, about 40 years old, had an apoplectic seizure after great exertion from fear; she had lain about 24 hours without speech, or having swallowed any liquid. She was then forcibly raised in bed, and a spoonful of solution of aloes in wine put into her mouth, and the end of the spoon withdrawn, that she might more easily swallow the liquid.--This was done every hour, with broth, and wine and water intervening, till evacuations were procured; which with other means had good effect, and she recovered, except that a considerable degree of hemiplegia remained, and some imperfection of her speech. Many people, who have taken so much vinous spirit as to acquire the temporary apoplexy of intoxication, and are not improperly said to be dead-drunk, have died after copious venesection, I suppose in consequence of it. I once saw at a public meeting two gentlemen in the drunken apoplexy; they were totally insensible with low pulse, on this account they were directed not to lose blood, but to be laid on a bed with their heads high, and to be turned every half hour; as soon as they could swallow, warm tea was given them, which evacuated their stomachs, and they gradually recovered, as people do from less degrees of intoxication. M. M. Cupping on the occiput. Venesection once in moderate quantity. Warm fomentations long continued and frequently repeated on the shaved head. Solution of aloes. Clysters with solution of aloe and oil of amber. A blister on the spine. An emetic. Afterwards the bark, and small doses of chalybeates. Small electric shocks through the head. Errhines. If small doses of opium? 17. _Mors a frigore._ Death from cold. The unfortunate travellers, who almost every winter perish in the snow, are much exhausted by their efforts to proceed on their journey, as well as benumbed by cold. And as much greater exercise can be borne without fatigue in cold weather than in warm; because the excessive motions of the cutaneous vessels are thus prevented, and the consequent waste of sensorial power; it may be inferred, that the fatigued traveller becomes paralytic from violent exertion as well as by the application of cold. Great degrees of cold affect the motions of those vessels most, which have been generally excited into action by irritation; for when the feet are much benumbed by cold, and painful, and at the same time almost insensible to the touch of external objects, the voluntary muscles retain their motions, and we continue to walk on; the same happens to the fingers of children in throwing snow-balls, the voluntary motions of the muscles continue, though those of the cutaneous vessels are benumbed into inactivity. Mr. Thompson, an elderly gentleman of Shrewsbury, was seized with hemiplegia in the cold bath; which I suppose might be owing to some great energy of exertion, as much as to the coldness of the water. As in the instance given of Mr. Nairn, who, by the exertion to save his relation, perished himself. See Sect. XXXIV. 1. 7. Whence I conclude, that though heat is a fluid necessary to muscular motion, both perhaps by its stimulus, and by its keeping the minute component parts of the ultimate fibrils of the muscles or organs of sense at a proper distance from each other; yet that paralysis, properly so called, is the consequence of exhaustion of sensorial power by exertion. And that the accumulations of it during the torpor of the cutaneous vessels by exposure to cold, or of some internal viscus in the cold fits of agues, are frequently instrumental in recovering the use of paralytic limbs, or of the motions of other paralytic parts of the system. See Spec. 4. of this genus. Animal bodies resist the power of cold probably by their exertions in consequence of the pain of cold, see Botan. Gard. V. 1. additional note xii. But if these increased exertions be too violent, so as to exhaust the sensorial power in producing unnecessary motions, the animal will probably sooner perish. Thus a moderate quantity of wine or spirit repeated at proper intervals of time might be of service to those, who are long exposed to excessive cold, both by increasing the action of the capillary vessels, and thus producing heat, and perhaps by increasing in some degree the secretion of sensorial power in the brain. But the contrary must happen when taken immoderately, and not at due intervals. A well attested history was once related to me of two men, who set out on foot to travel in the snow, one of whom drank two or three glasses of brandy before they began their journey, the other contented himself with his usual diet and potation; the former of whom perished in spite of any assistance his companion could afford him; and the other performed his journey with safety. In this case the sensorial power was exhausted by the unnecessary motions of incipient intoxication by the stimulus of the brandy, as well as by the exertions of walking; which so weakened the dram-drinker, that the cold sooner destroyed him; that is, he had not power to produce sufficient muscular or arterial action, and in consequence sufficient heat, to supply the great expenditure of it. Hence the capillaries of the skin first cease to act, and become pale and empty; next those which are immediately associated with them, as the extremities of the pulmonary artery, as happens on going into the cold bath. By the continued inaction of these parts of the vascular system the blood becomes accumulated in the internal arteries, and the brain is supposed to be affected by its compression; because these patients are said to sleep, or to become apoplectic, before they die. I overtook a fishman asleep on his panniers on a very cold frosty night, but on waking him he did not appear to be in any degree of stupor. See Class I. 2. 2. 1. When travellers are benighted in deep snow, they might frequently be saved by covering themselves in it, except a small aperture for air; in which situation the lives of hares, sheep, and other animals, are so often preserved. The snow, both in respect to its component parts, and to the air contained in its pores, is a bad conductor of heat, and will therefore well keep out the external cold; and as the water, when part of it dissolves, is attracted into the pores of the remainder of it, the situation of an animal beneath it is perfectly dry; and, if he is in contact with the earth, he is in a degree of heat between 48, the medium heat of the earth, and 32, the freezing point; that is, in 40 degrees of heat, in which a man thus covered will be as warm as in bed. See Botan. Garden, V. II. notes on Anemone, Barometz, and Muschus. If these facts were more generally understood, it might annually save the lives of many. After any part of the vascular system of the body has been long exposed to cold, the sensorial power is so much accumulated in it, that on coming into a warm room the pain of hotach is produced, and inflammation, and consequent mortification, owing to the great exertion of those vessels, when again exposed to a moderate degree of warmth. See Sect. XII. 5. Whence the propriety of applying but very low degrees of heat to limbs benumbed with cold at first, as of snow in its state of dissolving, which is at 32 degrees of heat, or of very cold water. A French writer has observed, that if frozen apples be thawed gradually by covering them with thawing snow, or immersing them in very cold water, that they do not lose their taste; if this fact was well ascertained, it might teach us how to preserve other ripe fruits in ice-houses for winter consumption. * * * * * ORDO II. _Decreased Volition._ GENUS II. _With decreased Actions of the Organs of Sense._ SPECIES. 1. _Recollectionis jactura._ Loss of recollection. This is the defect of memory in old people, who forget the actions of yesterday, being incapable of voluntary recollection, and yet remember those of their youth, which by frequent repetition are introduced by association or suggestion. This is properly the paralysis of the mind; the organs of sense do not obey the voluntary power; that is, our ideas cannot be recollected, or acted over again by the will. After an apoplectic attack the patients, on beginning to recover, find themselves most at a loss in recollecting proper names of persons or places; as those words have not been so frequently associated with the ideas they stand for, as the common words of a language. Mr. ----, a man of strong mind, of a short necked family, many of whom had suffered by apoplexy, after an apoplectic fit on his recovering the use of speech, after repeated trials to remember the name of a person or place, applauded himself, when he succeeded, with such a childish smile on the partial return of his sagacity, as very much affected me.--Not long, alas! to return; for another attack in a few weeks destroyed the whole. I saw a child after the small-pox, which was left in this situation; it was lively, active, and even vigorous; but shewed that kind of surprise, which novelty excites, at every object it viewed; and that as often as it viewed it. I never heard the termination of the case. 2. _Stultitia voluntaria._ Voluntary folly. The absence of voluntary power and consequent incapacity to compare the ideas of present and future good. Brute animals may be said to be in this situation, as they are in general excited into action only by their present painful or pleasurable sensations. Hence though they are liable to surprise, when their passing trains of ideas are dissevered by violent stimuli; yet are they not affected with wonder or astonishment at the novelty of objects; as they possess but in a very inferior degree, that voluntary power of comparing the present ideas with those previously acquired, which distinguishes mankind; and is termed analogical reasoning, when deliberatively exerted; and intuitive analogy, when used without our attention to it, and which always preserves our hourly trains of ideas consistent with truth and nature. See Sect. XVII. 3. 7. 3. _Credulitas._ Credulity. Life is short, opportunities of knowledge rare; our senses are fallacious, our reasonings uncertain, mankind therefore struggles with perpetual error from the cradle to the coffin. He is necessitated to correct experiment by analogy, and analogy by experiment; and not always to rest satisfied in the belief of facts even with this two-fold testimony, till future opportunities, or the observations of others, concur in their support. Ignorance and credulity have ever been companions, and have misled and enslaved mankind; philosophy has in all ages endeavoured to oppose their progress, and to loosen the shackles they had imposed; philosophers have on this account been called unbelievers: unbelievers of what? of the fictions of fancy, of witchcraft, hobgobblins, apparitions, vampires, fairies; of the influence of stars on human actions, miracles wrought by the bones of saints, the flights of ominous birds, the predictions from the bowels of dying animals, expounders of dreams, fortune-tellers, conjurors, modern prophets, necromancy, cheiromancy, animal magnetism, with endless variety of folly? These they have disbelieved and despised, but have ever bowed their hoary heads to Truth and Nature. Mankind may be divided in respect to the facility of their belief or conviction into two classes; those, who are ready to assent to single facts from the evidence of their senses, or from the serious assertions of others; and those, who require analogy to corroborate or authenticate them. Our first knowledge is acquired by our senses; but these are liable to deceive us, and we learn to detect these deceptions by comparing the ideas presented to us by one sense with those presented by another. Thus when we first view a cylinder, it appears to the eye as a flat surface with different shades on it, till we correct this idea by the sense of touch, and find its surface to be circular; that is, having some parts gradually receding further from the eye than others. So when a child, or a cat, or a bird, first sees its own image in a looking-glass, it believes that another animal exists before it, and detects this fallacy by going behind the glass to examine, if another tangible animal really exists there. Another exuberant source of error consists in the false notions, which we receive in our early years from the design or ignorance of our instructors, which affect all our future reasoning by their perpetual intrusions; as those habits of muscular actions of the face or limbs, which are called tricks, when contracted in infancy continue to the end of our lives. A third great source of error is the vivacity of our ideas of imagination, which perpetually intrude themselves by various associations, and compose the farrago of our dreams; in which, by the suspension of volition, we are precluded from comparing the ideas of one sense with those of another, or the incongruity of their successions with the usual course of nature, and thus to detect their fallacy. Which we do in our waking hours by a perpetual voluntary exertion, a process of the mind above mentioned, which we have termed intuitive analogy. Sect. XVII. 3. 7. This analogy presupposes an acquired knowledge of things, hence children and ignorant people are the most credulous, as not possessing much knowledge of the usual course of nature; and secondly, those are most credulous, whose faculty of comparing ideas, or the voluntary exertion of it, is slow or imperfect. Thus if the power of the magnetic needle of turning towards the north, or the shock given by touching both sides of an electrized coated jar, was related for the first time to a philosopher, and to an ignorant person; the former would be less ready to believe them, than the latter; as he would find nothing similar in nature to compare them to, he would again and again repeat the experiment, before he would give it his entire credence; till by these repetitions it would cease to be a single fact, and would therefore gain the evidence of analogy. But the latter, as having less knowledge of nature, and less facility of voluntary exertion, would more readily believe the assertions of others, or a single fact, as presented to his own observation. Of this kind are the bulk of mankind; they continue throughout their lives in a state of childhood, and have thus been the dupes of priests and politicians in all countries and in all ages of the world. In regard to religious matters, there is an intellectual cowardice instilled into the minds of the people from their infancy; which prevents their inquiry: credulity is made an indispensable virtue; to inquire or exert their reason in religious matters is denounced as sinful; and in the catholic church is punished with more severe penances than moral crimes. But in respect to our belief of the supposed medical facts, which are published by variety of authors; many of whom are ignorant, and therefore credulous; the golden rule of David Hume may be applied with great advantage. "When two miraculous assertions oppose each other, believe the less miraculous." Thus if a person is said to have received the small-pox a second time, and to have gone through all the stages of it, one may thus reason: twenty thousand people have been exposed to the variolous contagion a second time without receiving the variolous fever, to every one who has been said to have thus received it; it appears therefore less miraculous, that the assertor of this supposed fact has been deceived, or wishes to deceive, than that it has so happened contrary to the long experienced order of nature. M. M. The method of cure is to increase our knowledge of the laws of nature, and our habit of comparing whatever ideas are presented to us with those known laws, and thus to counteract the fallacies of our senses, to emancipate ourselves from the false impressions which we have imbibed in our infancy, and to set the faculty of reason above that of imagination. * * * * * _The Orders and Genera of the Fourth Class of Diseases._ CLASS IV. DISEASES OF ASSOCIATION. ORDO I. _Increased Associate Motions._ GENERA. 1. Catenated with irritative motions. 2. Catenated with sensitive motions. 3. Catenated with voluntary motions. 4. Catenated with external influences. ORDO II. _Decreased Associate Motions._ GENERA. 1. Catenated with irritative motions. 2. Catenated with sensitive motions. 3. Catenated with voluntary motions. 4. Catenated with external influences. ORDO III. _Retrograde Associate Motions._ GENERA. 1. Catenated with irritative motions. 2. Catenated with sensitive motions. 3. Catenated with voluntary motions. 4. Catenated with external influences. * * * * * _The Orders, Genera, and Species, of the Fourth Class of Diseases._ * * * * * CLASS IV. DISEASES OF ASSOCIATION. ORDO I. _Increased Associate Motions._ GENUS I. _Catenated with Irritative Motions._ SPECIES. 1. _Rubor vultûs pransorum._ Flushing of the face after dinner. 2. _Sudor stragulis immersorum._ Sweat from covering the face in bed. 3. _Cessatio ægritudinis cute_ Cure of sickness by stimulating _excitata._ the skin. 4. _Digestio aucta frigore cutaneo._ Digestion increased by coldness of the skin. 5. _Catarrhus a frigore cutaneo._ Catarrh from cold skin. 6. _Absorptio cellularis aucta_ Cellular absorption increased by _vomitu._ vomiting. 7. _Syngultus nephriticus._ Nephritic hiccough. 8. _Febris irritativa._ Irritative fever. GENUS II. _Catenated with Sensitive Motions._ SPECIES. 1. _Lacrymarum fluxus_ Sympathetic tears. _sympatheticus._ 2. _Sternutatio a lumine._ Sneezing from light. 3. _Dolor dentium a Stridore._ Tooth-edge from grating sounds. 4. _Risus sardonicus._ Sardonic smile. 5. _Salivæ fluxus cibo viso._ Flux of saliva at sight of food. 6. _Tensio mamularum viso puerulo._ Tension of the nipples of lactescent women at sight of the child. 7. _Tensio penis in hydrophobia._ Tension of the penis in hydrophobia. 8. _Tenesmus calculosus._ Tenesmus from stone. 9. _Polypus narium ex ascaride._ Polypus of the nose from ascarides. 10. _Crampus surarum in diarrhoea._ Cramp from diarrhoea. 11. _Zona ignea nephritica._ Nephritic shingles. 12. _Eruptio variolarum._ Eruption of small-pox. 13. _Gutta rosea stomatica._ Stomatic rosy drop. 14. ---- _hepatica._ Hepatic rosy drop. 15. _Podagra._ Gout. 16. _Rheumatismus._ Rheumatism. 17. _Erysipelas._ Erysipelas. 18. _Testium tumor in gonorrhoea._ Swelled testis in gonorrhoea. 19. ---- _in parotitide._ ---- in mumps. GENUS III. _Catenated with Voluntary Motions._ SPECIES. 1. _Deglutitio invita._ Involuntary deglutition. 2. _Nictitatio invita._ ---- nictitation. 3. _Risus invitus._ ---- laughter. 4. _Lusus digitorum invitus._ ---- actions with the fingers. 5. _Unguium morsiuncula invita._ ---- biting the nails. 6. _Vigilia invita._ ---- watchfulness. GENUS IV. _Catenated with External Influences._ SPECIES. 1. _Vita ovi._ Life of an egg. 2. _Vita hiemi-dormientium._ Life of winter-sleepers. 3. _Pullulatio arborum._ Budding of trees. 4. _Orgasmatis venerei periodus._ Periods of venereal desire. 5. _Brachii concussio electrica._ Electric shock through the arm. 6. _Oxygenatio sanguinis._ Oxygenation of the blood. 7. _Humectatio corporis._ Humectation of the body. ORDO II. _Decreased Associate Motions._ GENUS I. _Catenated with Irritative Motions._ SPECIES. 1. _Cutis frigida pransorum._ Chillness after dinner. 2. _Pallor urinæ pransorum._ Pale urine after dinner. 3. ---- _a frigore cutaneo._ ---- from cold skin. 4. _Pallor ex ægritudine._ Paleness from sickness. 5. _Dyspnoea a balneo frigido._ Shortness of breath from cold bathing. 6. _Dyspepsia a pedibus frigidis._ Indigestion from cold feet. 7. _Tussis a pedibus frigidis._ Cough from cold feet. 8. ---- _hepatica._ Liver-cough. 9. ---- _arthritica._ Gout-cough. 10. _Vertigo rotatoria._ Vertigo rotatory. 11. ---- _visualis._ ---- visual. 12. ---- _ebriosa._ ---- inebriate. 13. ---- _febriculosa._ ---- feverish. 14. ---- _cerebrosa._ ---- from the brain. 15. _Murmur aurium vertiginosum._ Noise in the ears. 16. _Tactus, gustus, olfactus_ Vertiginous touch, taste, smell. _vertiginosi._ 17. _Pulsus mollis a vomitione._ Soft pulse in vomiting. 18. ---- _intermittens a ventriculo._ Intermittent pulse from the stomach. 19. _Febris inirritativa._ Inirritative fever. GENUS II. _Catenated with Sensitive Motions._ SPECIES. 1. _Torpor genæ a dolore dentis._ Coldness of the cheek from tooth-ach. 2. _Stranguria a dolore vesicæ._ Strangury from pain of the bladder. 3. ---- _convulsiva._ Convulsive strangury. 4. _Dolor termini ductûs_ Pain of the end of the bile-duct. _choledochi._ 5. _Dolor pharyngis ab acido_ Pain of the throat from gastric acid. _gastrico._ 6. _Pruritus narium a vermibus._ Itching of the nose from worms. 7. _Cephalæa._ Head-ach. 8. _Hemicrania et otalgia._ Partial head-ach, and ear-ach. 9. _Dolor humeri in hepatitide._ Pain of shoulder in hepatitis. 10. _Torpor pedum variolâ_ Cold feet in eruption of small-pox. _erumpente._ 11. _Testium dolor nephriticus._ Nephritic pain of testis. 12. _Dolor digiti minimi_ Pain of little finger from sympathy. _sympatheticus._ 13. _Dolor brachii in hydrope_ Pain of the arm in dropsy of the _pectoris._ chest. 14. _Diarrhoea a dentitione._ Diarrhoea from toothing. GENUS III. _Catenated with Voluntary Motions._ SPECIES. 1. _Titubatio linguæ._ Impediment of speech. 2. _Chorea sancti viti._ St. Vitus' dance. 3. _Risus._ Laughter. 4. _Tremor ex irâ._ Trembling from anger. 5. _Rubor ex irâ._ Redness from anger. 6. ---- _criminati._ Blush of guilt. 7. _Tarditas paralytica._ Slowness from palsy. 8. ---- _senilis._ ---- of age. GENUS IV. _Catenated with External Influences._ SPECIES. 1. _Somni periodus._ Periods of sleep. 2. _Studii inanis periodus._ ---- of reverie. 3. _Hemicraniæ periodus._ ---- of head-ach. 4. _Epilepsiæ dolorificæ periodus._ ---- of painful epilepsy. 5. _Convulsionis dolorificæ periodus._ ---- of painful convulsion. 6. _Tussis periodicæ periodus._ ---- of periodic cough. 7. _Catameniæ periodus._ ---- of catamenia. 8. _Hæmorrhoidis periodus._ ---- of the piles. 9. _Podagræ periodus._ ---- of the gout. 10. _Erysipelatis periodus._ ---- of erysipelas. 11. _Febrium periodus._ ---- of fevers. ORDO III. _Retrograde Associate Motions._ GENUS I. _Catenated with Irritative Motions._ SPECIES. 1. _Diabætes irritata._ Diabetes from irritation. 2. _Sudor frigidus in asthmate._ Cold sweat in asthma. 3. _Diabætes a timore._ Diabetes from fear. 4. _Diarrhoea a timore._ Diarrhoea from fear. 5. _Pallor et tremor a timore._ Paleness and trembling from fear. 6. _Palpitatio cordis a timore._ Palpitation of the heart from fear. 7. _Abortio a timore._ Abortion from fear. 8. _Hysteria a timore._ Hysterics from fear. GENUS II. _Catenated with Sensitive Motions._ SPECIES. 1. _Nausea idealis._ Nausea from ideas. 2. ---- _a conceptu._ Nausea from conception. 3. _Vomitio vertiginosa._ Vomiting from vertigo. 4. ---- _a calculo in uretere._ ---- from stone in the ureter. 5. ---- _ab insultu paralytico._ ---- from stroke of palsy. 6. ---- _a titilatione faucium._ ---- from tickling the throat. 7. ---- _cute sympathetica._ ---- from sympathy with the skin. GENUS III. _Catenated with Voluntary Motions._ SPECIES. 1. _Ruminatio._ Rumination. 2. _Vomitio voluntaria._ Voluntary vomiting. 3. _Eructatio voluntaria._ ---- eructation. GENUS IV. _Catenated with External Influences._ SPECIES. 1. _Catarrhus periodicus._ Periodical catarrh. 2. _Tussis periodica._ Periodic cough. 3. _Histeria a frigore._ Hysterics from cold. 4. _Nausea pluvialis._ Sickness against rain. * * * * * CLASS IV. DISEASES OF ASSOCIATION. ORDO I. _Increased Associate Motions._ GENUS I. _Catenated with Irritative Motion._ The importance of the subsequent class not only consists in its elucidating all the sympathetic diseases, but in its opening _a road to the knowledge of fever_. The difficulty and novelty of the subject must plead in excuse for the present imperfect state of it. The reader is entreated previously to attend to the following circumstances for the greater facility of investigating their intricate connections; which I shall enumerate under the following heads. A. Associate motions distinguished from catenations. B. Associate motions of three kinds. C. Associations affected by external influences. D. Associations affected by other sensorial motions. E. Associations catenated with sensation. F. Direct and reverse sympathy. G. Associations affected four ways. H. Origin of associations. I. Of the action of vomiting. K. Tertian associations. A. _Associate Motions distinguished from Catenations._ Associate motions properly mean only those, which are caused by the sensorial power of association. Whence it appears, that those fibrous motions, which constitute the introductory link of an associate train of motions, are excluded from this definition, as not being themselves caused by the sensorial power of association, but by irritation, or sensation, or volition. I shall give for example the flushing of the face after dinner; the capillary vessels of the face increase their actions in consequence of their catenation, not their association, with those of the stomach; which latter are caused to act with greater energy by the irritation excited by the stimulus of food. These capillaries of the face are associated with each other reciprocally, as being all of them excited by the sensorial power of association; but they are only catenated with those of the stomach, which are not in this case associate motions but irritative ones. The common use of the word association for almost every kind of connection has rendered this subject difficult; from which inaccuracy I fear some parts of this work are not exempt. B. _Associate Motions of three Kinds._ Those trains or tribes of associate motions, whose introductory link consists of an irritative motion, are termed irritative associations; as when the muscles of the eyelids close the eye in common nictitation. Those, whose introductory link consists of a sensitive motion, are termed sensitive associations; as when the pectoral and intercostal muscles act in sneezing. And lastly, those, whose introductory link consists of a voluntary motion, are termed voluntary associations; as when the muscles of the lower limbs act in concert with those of the arm in fencing. C. _Associations affected by external Influences._ Circles of associate motions, as well as trains and tribes of them, are liable to be affected by external influences, which consist of etherial fluids, and which, by penetrating the system, act upon it perhaps rather as a causa sine quâ non of its movements, than directly as a stimulus; except when they are accumulated in unusual quantity. We have a sense adapted to the perception of the excess or defect of one of these fluids; I mean that of elementary heat; in which all things are immersed. See Class IV. 1. 4. 7. But there are others of them, which as we have no power to evade their influence, so we have no sense to perceive it; these are the solar, and lunar, and terrestrial gravitation, in which also all things are immersed; the electric aura, which pervades us, and is perpetually varying, See Class IV. 1. 4. 5; the magnetic fluid, Class IV. 1. 4. 5; and lastly, the great life-preserver oxygen gas, and the aqueous vapour of the atmosphere, see Class IV. 1. 4. 6. and 7. and 2. Of these external influences those of heat, and of gravity, have diurnal periods of increase and decrease; besides their greater periods of monthly or annual variation. The manner in which they act by periodical increments on the system, till some effect is produced, is spoken of in Sect. XXXII. 3. and 6. D. _Associations affected by other Sensorial Motions._ Circles and trains of associate motions are also liable to be affected by their catenations with other sensorial powers, as of irritation, or sensation, or volition; which other sensorial powers either thus simply form some of the links of the catenation, or add to the energy of the associated motions. Thus when vomiting is caused by the stimulus of a stone in the ureter, the sensation of pain seems to be a link of the catenation rather than an efficient cause of the vomiting. But when the capillary vessels of the skin increase their action from the influence of external heat, they are excited both by the stimulus of unusual heat, as well as by the stimulus of the blood, and by their accustomed association with the actions of the heart and arteries. And lastly, in the blush of anger the sensorial power of volition is added to that of association, and irritation, to excite the capillaries of the face with increased action. See Class IV. 2. 3. 5. E. _Associations catenated with Sensation._ Pain frequently accompanies associate trains or circles of motion without its being a cause, or a link, of them, but simply an attendant symptom; though it frequently gives name to the disease, as head-ach. Thus in the cramp of the calves of the legs in diarrhoea, the increased sensorial power of association is the proximate cause; the preceding increased action of the bowels is the remote cause; and the proximate effect is the violent contractions of the musculi gastrocnemii; but the pain of these muscles is only an attendant symptom, or a remote effect. See Sect. XVIII. 15. Other sensitive associations are mentioned in Class IV. 1. 2. and IV. 1. 2. 15. Thus, if the flushing of the face above mentioned after dinner be called a disease, the immediate or proximate cause is the increased power of association, the remote cause is the increased irritative motions of the stomach in consequence of the stimulus of food and wine. The disease or proximate effect consists in the increased actions of the cutaneous vessels of the face; and the sensation of heat, the existence of heat, and the red colour, are attendants or symptoms, or remote effects, of the increased actions of these cutaneous vessels. F. _Direct and reverse Sympathy._ The increased actions of the primary part of the trains of associated motions are sometimes succeeded by increased actions of the secondary part of the train; and sometimes by decreased actions of it. So likewise the decreased actions of the primary part of a train of associate motions are sometimes succeeded by decreased actions of the secondary part, and sometimes by increased actions of it. The former of these situations is called direct sympathy, and the latter reverse sympathy. In general I believe, where the primary part of the train of associated motions is exerted more than natural, it produces direct sympathy in strong people, and reverse sympathy in weak ones, as a full meal makes some people hot, and others chill. And where the primary part of the train is exerted less than natural, it produces direct sympathy in weak people, and reverse sympathy in strong ones, as on being exposed for a certain length of time on horseback in a cold day gives indigestion and consequent heart-burn to weak people, and strengthens the digestion, and induces consequent hunger in strong ones. See Sect. XXXV. 1. This may perhaps be more easily understood, by considering strength and weakness, when applied to animal bodies, as consisting in the quantity of sensorial power residing in the contracting fibres, and the quantity of stimulus applied, as shewn in Sect. XII. 2. 1. Now when defective stimulus, within certain limits, is partially applied to parts subject to perpetual motion, the expenditure of sensorial power is for a while lessened, but not its general production in the brain, nor its derivation into the weakly-stimulated part. Hence in strong people, or such whose fibres abound with sensorial power, if the first tribe of an associate train of motions be deprived in part of its accustomed stimulus, its action becomes diminished; and the sensorial power becomes accumulated, and by its superabundance, or overflowing as it were, increases the action of the second tribe of the associate actions by reverse sympathy. As exposing the warm skin for a moderate time to cold air increases the action of the stomach, and thus strengthens the power of digestion. On the reverse, when additional stimulus within certain limits is partially applied to parts, which are deficient in respect to the natural quantity of sensorial power, the expenditure of sensorial power is increased, but in a less degree than the increased production of it in the brain, or its increased derivation into the strongly-stimulated organ. Hence in weak people, or such whose fibres are deficient of sensorial power, if the first tribe of an associate train of motions be subjected for a while to greater stimulus than usual, a greater production of sensorial power, or a greater derivation of it into the stimulated parts occurs; which by its excess, or overflowing as it were, increases the actions of the second tribe of the associate motions by direct sympathy. Thus when vomiting occurs with cold extremities, a blister on the back in a few hours occasions universal warmth of the skin, and stops the vomiting. And when a diarrhoea occurs with pale skin and cold extremities, the pricking of the points of a flannel shirt, worn next the skin, occasions universal warmth of it, and checks or cures the diarrhoea. In some associate trains of action nevertheless reverse sympathies more frequently occur than direct ones, and in others direct ones more frequently than reverse ones. Thus in continued fever with debility there appears to be a reverse sympathy between the capillary vessels of the stomach and those of the skin; because there exists a total aversion to solid food, and constant heat on the surface of the body. Yet these two systems of vessels are at other times actuated by direct sympathy, as when paleness attends sickness, or cold feet induces indigestion. This subject requires to be further investigated, as it probably depends not only on the present or previous plus or minus of the sensorial power of association, but also on the introduction of other kinds of sensorial power, as in Class IV. 1. 1. D; or the increased production of it in the brain, or the greater mobility of one part of a train of actions than another. Thus when much food or wine is taken into the stomach, if there be no superfluity of sensorial power in the system, that is, none to be spared from the continual actions of it, a paleness and chillness succeeds for a time; because now the expenditure of it by the increased actions of the stomach is greater than the present production of it. In a little time however the stimulus of the food and wine increases the production of sensorial power in the brain, and this produces a superfluity of it in the system; in consequence of which the skin now becomes warm and florid, which was at first cold and pale; and thus the reverse sympathy is shortly converted into a direct one; which is probably owing to the introduction of a second sensorial power, that of pleasurable sensation. On the contrary, when an emetic drug produces sickness, the skin is at first pale for a time by direct sympathy with the capillaries of the stomach; but in a few minutes, by the accumulation of sensorial power in the stomach during its less active state in sickness, the capillaries of the skin, which are associated with those of the stomach, act with greater energy by reverse sympathy, and a florid colour returns. Where the quantity of action is diminished in the first part of a train of motions, whether by previous diminution of sensorial power, or present diminution of stimulus, the second part of the train becomes torpid by direct sympathy. And when the quantity of action of the first part becomes increased by the accumulation of sensorial power during its previous torpor, or by increase of stimulus, the actions of the second part of it likewise become increased by direct sympathy. In moderate hunger the skin is pale, as before dinner, and in moderate sickness, as no great accumulation of sensorial power has commenced; but in violent hunger, and in greater torpor of the stomach, as from contagious matter, the accumulation of sensorial power becomes so great as to affect the arterial and capillary system, and fever is produced in both cases. In contagious fevers with arterial debilities commencing with torpor of the stomach, why is the action of the heart weakened, and that of the capillaries increased? Is it because the mobility of the heart is less than that of the stomach, and the mobility of the capillaries greater? Or is it because the association between the muscular fibres of the stomach and those of the heart have been uniformly associated by direct sympathy; and the capillaries of the stomach and those of the skin have been more frequently associated by reverse sympathy? Where the actions of the stomach have been previously exhausted by long stimulus, as on the day after intoxication, little or no accumulation of sensorial power occurs, during the torpor of the organ, beyond what is required to replace the deficiency of it, and hence fever seldom follows intoxication. And a repetition of the stimulus sometimes becomes necessary even to induce its natural action, as in dram-drinkers. Where there has been no previous exhaustion of sensorial power, and the primary link of associate motions is violently actuated by the sensorial power of sensation, the secondary link is also violently actuated by direct sympathy, as in inflammatory fevers. Where however the sensorial power of the system is less than natural, the secondary link of associated motions becomes torpid by reverse sympathy, as in the inoculated small-pox during the eruption on the face the feet are frequently cold. G. _Associations affected four Ways._ Hence associated trains or circles of motions may be affected four different ways. 1. By the greater or less energy of action of the first link with which they are catenated, and from which they take their names; as irritative, sensitive, or voluntary associations. 2. By being excited by two or more sensorial powers at the same time, as by irritation and association, as in the instance of the application of the stimulus of increased external heat to the cutaneous capillaries. 3. By catenation with other sensorial powers, as with pain or pleasure, which are in this case not the proximate cause of motion, but which, by becoming a link of catenation, excites the sensorial power of association into action; as the pain at the neck of the gall-bladder occasioned by a gall-stone is transferred to the other end of that canal, and becomes a link of catenation between the action of the two extremities of it. 4. The influence of ethereal fluids, as of heat and gravitation. To which last perhaps might be added moisture and oxygen gas as constituting necessary parts of the system, rather than stimuli to excite it into action. H. _The Origin of Associations._ Some trains or circles of associate motions must have been formed before our nativity, as those of the heart, arteries, and capillaries; others have been associated, as occasion required them, as the muscles of the diaphragm and abdomen in vomiting; and others by perpetual habit, as those of the stomach with the heart and arteries directly, as in weak pulse during sickness; with the capillaries directly, as in the flushed skin after dinner; and lastly, with the cellular absorbents reversely, as in the increased absorption in anasarca during sickness; and with the irritative motions of the organs of sense reversely, as in vertigo, or sea-sickness. Some of these associations shall be here shortly described to facilitate the investigation of others. First, other congeries of glands occupy but a particular part of the system, or constitute a particular organ, as the liver, or kidneys; but those glands, which secrete the mucus, and perspirable matter, which are called capillaries, are of very great extent; they receive the blood from the arteries, separate from it the mucus, which lines every cell, and covers every cavity of body; and the perspirable matter, which softens and lubricates the whole surface of the skin, and the more extensive surface of the air-vessels, which compose the lungs. These are supplied with blood by the perpetual action of the heart and arteries, and have therefore their motions associated with the former, and with each other, by sympathy, which is sometimes direct, and sometimes reverse. One branch of this association, the capillaries of the skin, are very irritable by the increased quantities of cold and heat, another branch, that of the lungs, has not the perception of cold and heat, but is liable by direct sympathy to act in concert with the former, as in going into the cold bath. And it is probable the capillaries of the internal membranes are likewise directly affected by their sympathy with those of the skin, as appears from the defect of secretion in ulcers during the cold fits of agues. The motions of this extensive system of capillaries, thus associated by direct sympathy, are also associated with those of the heart and arteries, sometimes by reverse and sometimes by direct sympathy; and thus constitute simple fever. The cold paroxysm of which consists in their torpor, and the hot one in their orgasm, or increased activity. I. _Of the Action of Vomiting._ The manner, in which the stomach and the diaphragm and abdominal muscles acquire their associate action in vomiting, requires some attention. It is not probable, that this action of vomiting occurs before nativity; as the uniform application of the nutritive liquor amnii to the mouth of the foetus, and the uniform expenditure of its nourishment, would not seem to give occasion to too great temporary repletion of the stomach; and would preclude the deglutition of any improper material. After nativity the stomach of the child may be occasionally too much distended with milk; as previous hunger may induce it to overgorge itself; and by repeated efforts the act of vomiting is learned, as a means of getting free from a disagreeable sensation. Thus when any disgustful material, as a bitter drug, is taken into the mouth; certain retrograde motions of the tongue and lips are produced, for the purpose of putting the disagreeable material out of the mouth again. When the stomach is disagreeably stimulated by the distention or acrimony of the aliment, a similar effort to regurgitate it must occur; and by repeated trials the action of the diaphragm and abdominal muscles by squeezing the stomach assists its retrograde exertion to disgorge its contents. In the same manner when a piece of gravel is pushed into the urethra, or a piece of indurated bile into the neck of the gall-bladder, after they have been in vain pressed forward by the usual motions of those ducts, they return into the bladders of gall and urine by the retrograde motions of them. That this is one mode, in which vomiting is induced, appears from the instantaneous rejection from the stomach occasioned by some nauseous drug, or from some nauseous idea; and lastly, from the voluntary power, which some people have been said to have acquired, of emptying their stomachs, much in the same manner as ruminating animals bring up the grass from their first stomach. There are nevertheless many modes by which these inverted motions of the stomach and oesophagus are induced, and which it is of consequence to distinguish from each other. The first is the mode above described, where an effort is made to dislodge something, which stimulates the stomach into disagreeable sensation; and which is returned by repeated exertions; as when a nauseous drug is taken into the mouth, or a bit of sand falls into the eye, or a drop of water into the wind-pipe. In this the peristaltic motions of the stomach are first stopped, and then reverted by painful sensation; and the abdominal muscles and diaphragm by repeated efforts become associated with them. Now as less sensorial power is expended on the retrograde actions of the stomach, and of the lymphatics, which open their mouths on its surface, than by their natural motions, an accumulation of sensorial power in the fibres of the stomach follows the exhibition of an emetic, and on that account an emetic will sometimes stop a spontaneous vomiting which was owing to sensorial deficiency. See Sect. XXXV. 1. 3. and Art. V. 2. 1. As bitters and metallic salts, exhibited in small doses, stimulate the stomach into greater action, as appears by their increasing the power of digestion, and yet become emetic, when given in larger doses; one might suspect, that they became emetic by inducing debility, and consequent retrograde actions of the stomach, by their previously exhausting the sensorial power by their great stimulus; which might be effected in a moment without producing pain, and in consequence without our perceiving it. But on the contrary, there does not in general appear on the exhibition of emetics to be any previous exhaustion of sensorial power; because there is evidently an accumulation of it during the sickness, as appears from the digestion being stronger afterwards; and from the increased action of the cellular and cutaneous absorbents during its operation. See Art. V. 2. 1. Another mode, by which vomiting is induced, is owing to debility or deficiency of sensorial power, from the previous exhaustion of it; as on the day after intoxication, or which occurs in people enfeebled with the gout, and in dropsy, and in some fevers with debility. In these, when the vomiting ceases, there is no appearance of accumulation of sensorial power, as the digestion still remains weak and imperfect. Another mode by which sickness or vomiting is induced, is by defect of stimulus, as in great hunger; and in those, who have been habituated to spice and spirit with their meals, who are liable to be sick after taking food without these additional stimuli. Other means of inducing sickness by vertigo, or by nauseous ideas, will be mentioned below. We shall only add, that the motions of the muscular fibres of the stomach are associated with those of the heart and arteries by direct sympathy, as appears by the weakness of the pulse during the exhibition of an emetic; and that the absorbents of the stomach are associated with the cellular and cutaneous absorbents by reverse sympathy, as is shewn by the great absorption of the mucus of the cells in anasarca during sickness; at the same time that the absorbents of the stomach invert their actions, and pour the mucus and water thus absorbed into that viscus. In cold paroxysms of fever the stomach partakes of the general torpor, and vomiting is induced by its debility, either by its association with the torpid capillaries, or other torpid parts, or by its own torpor commencing first, and causing the cold fit. The disordered motions of the stomach frequently seem to be the cause or primary seat of fever, as where contagious miasmata are swallowed with the saliva, and where fever is produced by sea-sickness, which I once saw. Nevertheless a disorder of the stomach does not always induce fever, as in that case it should constantly attend indigestion, and vertigo, and sea-sickness; but is itself frequently induced by association with the disordered movements of other parts of the system, as when it arises from gravel in the ureter, or from a percussion on the head. The connexion of the motions of the stomach with irritative ideas, or motions of the organs of sense, in vertigo, is shewn in Sect. XX. and thus it appears, that many circles of association are either directly or reversely associated, or catenated, with this viscus; which will much contribute to unfold some of the symptoms of fever. K. _Tertian Associations._ The third link of associate trains of motion is sometimes actuated by reverse sympathy, with the second link, and that by reverse sympathy with the first link; so that the first and third link may act by direct sympathy, and the intermediate one by reverse sympathy. Of this instances are given in the syngultus nephriticus, Class IV. 1. 1. 7. and IV. 2. 1. At other times the tertian or quartan links of associate motions are actuated by direct sympathy; and that sometimes forwards and sometimes backwards in respect to the usual order of those trains of associate motions, as in Class IV. 1. 2. 1. SPECIES. 1. _Rubor vultûs prandorum._ Flushing of the face after dinner is explained in Sect. XXXV. 1. In the beginning of intoxication the whole skin becomes florid from the association of the actions of the cutaneous arteries with those of the stomach, because vinous spirit excites the fibres of the stomach into more violent action than the stimulus of common food; and the cutaneous capillaries of the face, from their more frequent exposure to the vicissitudes of cold and heat, possess more mobility or irritability than those of other parts of the skin, as further explained in Sect. XXXIII. 2. 10. Vinegar is liable to produce this flushing of the face, which probably is owing to the quantity of vinous spirit it contains, as I believe the unfermented vegetable acids do not produce this effect. In every kind of blush the arterial blood is propelled into the capillaries faster than the venous absorption can carry it forwards into the veins, in this respect resembling the tensio phalli. Can the beginning vinous or acetous fermentation of the aliment in weak stomachs contribute to this effect? or is it to be ascribed to the greater power of association between the arteries of the face and the fibres of the stomach in some people than in others? M. M. Eat and drink less at a time, and more frequently. Put 20 drops of weak acid of vitriol into water to be drank at meals. Let the dress over the stomach and bowels be loose. Use no fermented liquors, or vinegar, or spice. 2. _Sudor stragulis immersorum._ Sweat from being covered in bed. In the commencement of an epidemic fever, in which the perpetual efforts to vomit was a distressing symptom, Dr. Sydenham discovered, that if the patient's head was for a short time covered over with the bed clothes, warmth was produced, and a sweat broke out upon the skin, and the tendency to vomit ceased. In this curious fact two trains of associated motions are excited into increased action. First, the vessels of the lungs are known to have their motion associated with those of the skin by the difficulty of breathing on going into the cold bath, as described in Sect. XXXII. 3. 2. Hence, when the vessels of the lungs become excited into stronger action, by the bad air under the bed clothes, warmed and adulterated by frequent breathing, those of the external skin soon become excited by their association into more energetic action, and generate more heat along with a greater secretion of perspirable matter. Secondly, the sympathy between the stomach and skin is evident in variety of circumstances; thus the cold air of frosty days applied to the skin for a short time increases the action of the stomach by reverse sympathy, but decreases it if continued too long by direct sympathy; so in the circumstance above mentioned the action of the stomach is increased by direct sympathy with that of the skin; and the tendency to vomit, which was owing to its diminished action, ceases. 3. _Cessatio ægritudinis cute excitatâ._ The cure of sickness by stimulating the skin. This is explained in the preceding article; and further noticed in IV. 2. 2. 4. and in IV. 1. 1. f. Similar to these is the effect of a blister on the back in relieving sickness, indigestion, and heart-burn; and, on the contrary, by these symptoms being frequently induced by coldness of the extremities. The blister stimulates the cutaneous vessels into greater action; whence warmth and pain are produced at the same time, and the fibres of the stomach are excited into greater action by their association with those of the skin. It does not appear, that the concomitant pain of the blister causes the increased energy of the stomach, because the motions of it are not greater than natural; though it is sometimes difficult to determine, whether the primary part of some associated trains be connected with irritative or sensitive motions. In the same manner a flannel shirt, to one who has not been in the habit of wearing one, stimulates the skin by its points, and thus stops vomiting in some cases; and is particularly efficacious in checking some chronical diarrhoeas, which are not attended with fever; for the absorbents of the skin are thus stimulated into greater action, with which those of the intestines consent by direct sympathy. This effect cannot be ascribed to the warmth alone of the flannel shirt, as being a covering of loose texture, and confining air in its pores, like a sponge, which air is known to be a bad conductor of heat, since in that case its use should be equally efficacious, if it were worn over a linen shirt; and an increased warmth of the room of the patient would be equally serviceable. 4. _Digestio aucta frigore cutaneo._ Digestion increased by coldness of the skin. Every one has experienced the increase of his appetite after walking in the cool air in frosty days; for there is at this time not only a saving of sensorial power by the less exertion of the cutaneous vessels; but, as these consent with those of the stomach and bowels, this saving of sensorial power is transferred by reverse sympathy from the cutaneous capillaries and absorbents to those of the stomach and intestines. Hence weak people should use the cold air of winter as a cold bath; that is, they should stay in it but a short time at once, but should immerse themselves in it many times a day. 5. _Catarrhus a frigore cutaneo._ Catarrh from cold skin. This has been already explained in Class I. 1. 2. 7. and is further described in Sect. XXXV. 1. 3. In this disease the vessels of the membrane, which lines the nostrils, are excited into greater action; when those of the skin, with which they are associated, are excited into less action by the deficiency of external heat, by reverse sympathy; and though the pain of cold attends the torpor of the primary link of this association, yet the increased motions of the membrane of the nostrils are associated with those of the cutaneous vessels, and not with the pain of them, because no inflammation follows. 6. _Absorptio cellularis aucta vomitu._ In the act of vomiting the irritative motions of the stomach are inverted, and of the absorbents, which open their mouths into it; while the cutaneous, cellular, and pulmonary absorbents are induced, by reverse sympathy with them, to act with greater energy. This is seen in cases of anasarca, when long sickness and vomiting are caused by squills, or antimonial salts, or most of all by the decoction of digitalis purpurea, foxglove; and Mr. J. Hunter mentions a case, in which a large bubo, which was just ready to break, was absorbed in a few days by sickness at sea. Treatise on the Blood, p. 501, which is thus accounted for; less sensorial power is expended during sickness by the decreased action of the fibres of the stomach, and of its absorbents; as shewn in Sect. XXXV. 1. 3. whence an accumulation of it is produced, and there is in consequence a greater quantity of sensorial power for the exertion of those motions, which are associated with the absorbents of the stomach by reverse sympathy. The reverse sympathy between the lacteal and lymphatic branches of the absorbent system have been produced by the one branch being less excited to act, when the other supplies sufficient fluid or nutriment to the sanguiferous vessels. Thus when the stomach is full, and the supply of chyle and mucus and water is in sufficient quantity; the pulmonary, cellular, and cutaneous lymphatics are not excited into action; whence the urine is pale, and the skin moist, from the defect of absorption on those surfaces. 7. _Syngultus nephriticus._ When a stone irritates the ureter, and that even without its being attended with pain or fever, sometimes a chronical hiccough occurs, and continues for days and weeks, instead of sickness or vomiting; which are the common symptoms. In this case the motions of the stomach are decreased by their sympathy with those of the ureter, which are increased by the stimulus of the stone in it; and the increased motions of the diaphragm seem to exist in consequence of their association with the stomach by a second reverse sympathy. This hiccough may nevertheless admit of another explanation, and be supposed to be a convulsive exertion of the diaphragm to relieve the disagreeable sensation of the stomach in consequence of its disordered irritative associations; and in that case it would belong to Class III. 1. 1. See Class IV. 2. 1. for another example of tertiary association. M. M. Venesection. Emetic. Calomel. Cathartic, opium, oil of cinnamon from two to ten drops. Aerated alcaline water. Peruvian bark. 8. _Febris irritativa._ Irritative fever, described in Class I. 1. 1. 1. The diseases above explained in this genus are chiefly concerning the sympathies of the absorbent system, or the alimentary canal, which are not so much associated with the arterial system, as to throw it into disorder, when they are slightly deranged; but when any great congeries of conglomerate glands, which may be considered as the extremities of the arterial system, are affected with torpor, the whole arterial system and the heart sympathize with the torpid glands, and act with less energy; which constitutes the cold fit of fever; which is therefore at first a decreased action of the associate organ; but as this decrease of action is only a temporary effect, and an increase of exertion both of the torpid glands, and of the whole arterial system, soon follows; the hot fit of irritative fever, or fever with strong pulse, properly belongs to this class and genus of diseases. * * * * * ORDO I. _Increased Associate Motions._ GENUS II. _Catenated with Sensitive Motions._ The primary links of the associated actions of this genus are either produced or attended by painful or pleasurable sensation. The secondary links of the first ten species are attended with increased motions without inflammation, those of the remainder are attended with inflammation. All inflammations, which do not arise in the part which was previously torpid, belong to this genus; as the gout, rheumatism, erysipelas. It is probable many other inflammations may, by future observation, require to be transplanted into this class. The circles of sensitive associate motions consist chiefly of the excretory ducts of the capillaries and of the mouths of the absorbent vessels, which constitute the membranes; and which have been induced into action at the same time; or they consist of the terminations of canals; or of parts which are endued with greater sensibility than those which form the first link of the association. An instance of the first of those is the sympathy between the membranes of the alveolar processes of the jaws, and the membranes above or beneath the muscles about the temples in hemicrania. An instance of the second is in the sympathy between the excretory duct of the lacrymal gland, and the nasal duct of the lacrymal sack. And an instance of the third is the sympathy between the membranes of the liver, and the skin of the face in the gutta rosea of inebriates. SPECIES. 1. _Lacrymarum fluxus sympatheticus._ A flow of tears from grief or joy. When the termination of the duct of the lacrymal sac in the nostrils becomes affected either by painful or pleasurable sensations, in consequence of external stimulus, or by its association with agreeable or disagreeable ideas, the motions of the lacrymal gland are at the same time exerted with greater energy, and a profusion of tears succeeds by sensitive association, as explained in Sect. XVI. 8. 2. In this case there exists a chain of associated actions, the secretion of the lacrymal gland is increased by whatever stimulates the surface of the eye, at the same time the increased abundance of tears stimulates the puncta lacrymalia into greater action; and the fluid thus absorbed stimulates the lacrymal sac, and its nasal duct in the nose into greater action. In a contrary direction of this chain of association the present increase of action is induced. First, the nasal duct of the lacrymal sac is excited into increased action by some pleasurable or painful idea, as described in Sect. XVI. 8. 2. 2d. The puncta lacrymalia or other extremity of the lacrymal sac sympathizes with it (as the two ends of all other canals sympathize with each other). 3d. With these increased motions of the puncta lacrymalia those of the excretory duct of the lacrymal gland are associated from their having so perpetually acted together. And, lastly, with the increased actions of the excretory duct of this gland are associated those of the other end of it by their frequently acting together; in the same manner as the extremities of other canals are associated; and thus a greater flow of tears is poured into the eye. When a flow of tears is produced in grief, it is believed to relieve the violence of it, which is worthy a further inquiry. Painful sensations, when great, excite the faculty of volition; and the person continues voluntarily to call up or perform those ideas, which occasion the painful sensation; that is, the afflicted person becomes so far insane or melancholy; but tears are produced by the sensorial faculty of association, and shew that the pain is so far relieved as not to excite the excessive power of volition, or insanity, and are therefore a sign of the abatement of the painful state of grief, rather than a cause of that abatement. See Class III. 1. 2. 10. 2. _Sternutatio a lumine._ Some persons sneeze from looking up at the light sky in a morning after coming out of a dark bedroom. The olfactory nerves are brought into too great action by their sympathy with the optic nerves, or by their respective sympathies with some intervening parts, as probably with the two extremities of the lacrymal sac; that is, with the puncta lacrymalia and the nasal duct. See Class II. 1. 1. 3. 3. _Dolor dentium Stridore._ Tooth-edge from grating sounds, and from the touch of certain substances, and even from imagination alone, is described and explained in Sect. XVI. 10. The increased actions of the alveolar vessels or membranes are associated with the ideas, or sensual motions of the auditory nerves in the first case; and of those of the sense of touch, in the second case; and by imagination, or ideas exerted of painful sensation alone, in the last. 4. _Risus sardonicus._ A disagreeable smile attends inflammations of the diaphragm arising from the associations of the reiterated exertions of that muscle with those of the lips and cheeks in laughing. See Diaphragmitis, Class II. 1. 2. 6. 5. _Salivæ fluxus cibo viso._ The flow of saliva into the mouths of hungry animals at the sight or smell of food is seen in dogs standing round a dinner-table. The increased actions of the salivary glands have been usually produced by the stimulus of agreeable food on their excretory ducts during the mastication of it; and with this increased action of their excretory ducts the other terminations of those glands in the capillary arteries have been excited into increased action by the mutual association of the ends of canals; and at the same time the pleasurable ideas, or sensual motions, of the sense of smell and of sight have accompanied this increased secretion of saliva. Hence this chain of motions becomes associated with those visual or olfactory ideas, or with the pleasure, which produces or attends them. 6. _Tensio mamularum viso puerulo._ The nipples of lactescent women are liable to become turgid at the sight of their young offspring. The nipple has generally been rendered turgid by the titillation of the lips or gums of the child in giving suck; the visible idea of the child has thus frequently accompanied this pleasurable sensation of parting with the milk, and turgescence of the tubes, which constitute the nipple. Hence the visual idea of the child, and the pleasure which attends it, become associated with those increased arterial actions, which swell the cells of the mamula, and extend its tubes; which is very similar to the tensio phalli visâ muliere nudâ etiam in insomnio. 7. _Tensio penis in hydrophobia._ An erection of the penis occurs in the hydrophobia, and is a troublesome symptom, as observed by Coelius Aurelianus, Fothergill, and Vaughn, and would seem to be produced by an unexplained sympathy between the sensations about the fauces and the penis. In men the hair grows about both these parts, the voice changes, and the neck thickens at puberty. In the mumps, when the swellings about the throat subsides, the testicles are liable to swell. Venereal infection received by the penis is very liable to affect the throat with ulcers. Violent coughs, with soreness or rawness about the fauces are often attended with erection of the penis; which is also said to happen to male animals, that are hanged; which last circumstance has generally been ascribed to the obstruction of the circulation of the blood, but is more probably occasioned by the stimulus of the cord in compressing the throat; since if it was owing to impeded circulation it ought equally to occur in drowning animals. In men the throat becomes so thickened at the time of puberty, that a measure of this is used to ascertain the payment of a poll-tax on males in some of the islands of the Mediterranean, which commences at puberty; a string is wrapped twice round the thinnest part of the neck, the ends of it are then put into each corner of the mouth; and if, when thus held in the teeth, it passes readily over the head, the subject is taxable. It is difficult to point out by what circumstance the sensitive motions of the penis and of the throat and nose become associated; I can only observe, that these parts are subjected to greater pleasurable sensations than any other parts of the body; one being designed to preserve ourselves by the pleasure attending the smell and deglutition of food, and the other to ensure the propagation of our species; and may thus gain an association of their sensitive motion by their being eminently sensible to pleasure. See Class I. 3. 1. 11. and III. 1. 1. 15. and Sect. XVI. 5. In the female sex this association between the face, throat, nose, and pubis does not exist; whence no hair grows on their chins at the time of puberty, nor does their voices change, or their necks thicken. This happens probably from there being in them a more exquisite sensitive sympathy between the pubis and the breasts. Hence their breasts swell at the time of puberty, and secrete milk at the time of parturition. And in the parotitis, or mumps, the breasts of women swell, when the tumor of the parotitis subsides. See Class I. 1. 2. 15. Whence it would appear, that their breasts possess an intermediate sympathy between the pubis and the throat; as they are the seat of a passion, which men do not possess, that of suckling children. 8. _Tenesmus calculosus._ The sphincter of the rectum becomes painful or inflamed from the association of its sensitive motions with those of the sphincter of the bladder, when the latter is stimulated into violent pain or inflammation by a stone. 9. _Polypus narium ex ascaridibus?_ The stimulation of ascarides in the rectum produces by sensitive sympathy an itching of the nose, as explained in IV. 2. 2. 6; and in three children I have seen a polypus in the nose, who were all affected with ascarides; to the perpetual stimulation of which, and the consequent sensitive association, I was led to ascribe the inflammation and thickening of the membrane of the nostrils. 10. _Crampus surarum in cholera._ A cramp of the muscles of the legs occurs in violent diarrhoea, or cholera, and from the use of too much acid diet in gouty habits. This seems to sympathize with uneasy sensation in the bowels. See Class III. 1. 1. 14. This association is not easily accounted for, but is analogous in some degree to the paralysis of the muscles of the arms in colica saturnina. It would seem, that the muscles of the legs in walking get a sympathy with the lower parts of the intestines, and those of the arms in variety of employment obtain a sympathy with the higher parts of them. See Cholera and Ileus. 11. _Zona ignea nephritica._ Nephritic shingles. The external skin about the loins and sides of the belly I suppose to have greater mobility in respect to sensitive association, than the external membrane of the kidney; and that their motions are by some unknown means thus associated. When the torpor or beginning inflammation of this membrane ceases, the external skin becomes inflamed, in its stead, and a kind of herpes, called the shingles, covers the loins and sides of the belly. See Class II. 1. 5. 9. 12. _Eruptio variolarum._ After the inflammation of the inoculated arm has spread for a quarter of a lunation, it affects the stomach by reverse sympathy; that is, the actions of the stomach are associated with those of the skin; and as much sensorial power is now exerted on the inflamed skin, the other part of this sensitive association is deprived of its natural share, and becomes torpid, or inverts its motions. After this torpor of the stomach has continued a time, and much sensorial power is thus accumulated; other parts of the skin, which are also associated with it, as that of the face first, are thrown into partial inflammation; that is, the eruptions of the small-pox appear on the face. For that the variolous matter affects the stomach previous to its eruption on the skin appears from the sickness at the commencement of the fever; and because, when the morbid motions affect the skin, those of the stomach cease; as in the gout and erysipelas, mentioned below. The consent between the stomach and the skin appears in variety of other diseases; and as they both consist of surfaces, which absorb and secrete a quantity of moisture, their motions must frequently be produced together or in succession; which is the foundation of all the sympathies of animal motions, whether of the irritative, sensitive, or voluntary kinds. Now as the skin, which covers the face, is exposed to greater variations of heat and cold than any other part of the body; it probably possesses more mobility to sensitive associations, not only than the stomach, but than any other part of the skin; and is thence affected at the eruption of the small-pox with violent action and consequent inflammation, by the association of its motions with those of the stomach, a day before the other parts of the skin; and becomes fuller of pustules, than any other part of the body. See Class II. 1. 3. 9. It might be supposed, that the successive swelling of the hands, when the face subsides, at the height of the small-pox, and of the feet, when the hands subside, were governed by some unknown associations of those parts of the system; but these successions of tumor and subsidence more evidently depend on the times of the eruption of the pustules on those parts, as they appear a day sooner on the face than on the hands, and a day sooner on the hands than on the feet, owing to the greater comparative mobility of those parts of the skin. 13. _Gutta rosea stomatica._ Stomatic red face. On drinking cold water, or cold milk, when heated with exercise, or on eating cold vegetables, as raw turnips, many people in harvest-time have been afflicted with what has been called a surfeit. The stomach becomes painful, with indigestion and flatulency, and after a few days an eruption of the face appears, and continues with some relief, but not with entire relief; as both the pimpled face and indigestion are liable to continue even to old age. M. M. Venesection. A cathartic with calomel. Then half a grain of opium twice a day for many weeks. If saturated solution of arsenic three or five drops twice or thrice a day for a week? 14. _Gutta rosea hepatica._ The rosy drop of the face of some drinking people is produced like the gout described below, in consequence of an inflamed liver. In these constitutions the skin of the face being exposed to greater variation of heat and cold than the membranes of the liver, possesses more mobility than those hepatic membranes; and hence by whatever means these membranes are induced to sympathize, when this sensitive association occurs, the cutaneous vessels of the face run into greater degrees of those motions, which constitute inflammation, than previously existed in the membranes of the liver; and then those motions of the liver cease. See Class II. 1. 4. 6. An inflammation of the liver so frequently attends the great potation of vinous spirit, there is reason to suspect, that this viscus itself becomes inflamed by sensitive association with the stomach; or that, when one termination of the bile-duct, which enters the duodenum is stimulated violently, the other end may become inflamed by sensitive association. 15. _Podagra._ The gout, except when it affects the liver or stomach, seems always to be a secondary disease, and, like the rheumatism and erysipelas mentioned below, begins with the torpor of some distant part of the system. The most frequent primary seat of the gout I suppose to be the liver, which is probably affected with torpor not only previous to the annual paroxysms of the gout, but to every change of its situation from one limb to another. The reasons, which induce me to suspect the liver to be first affected, are not only because the jaundice sometimes attends the commencement of gout, as described in Sect. XXIV. 2. 8. but a pain also over the pit of the stomach, which I suppose to be of the termination of the bile-duct in the duodenum, and which is erroneously supposed to be the gout of the stomach, with indigestion and flatulency, generally attends the commencement of the inflammation of each limb. See Arthritis ventriculi, Class I. 2. 4. 6. In the two cases, which I saw, of the gout in the limbs being preceded by jaundice, there was a cold shivering fit attended the inflammation of the foot, and a pain at the pit of the stomach; which ceased along with the jaundice, as soon as the foot became inflamed. This led me to suspect, that there was a torpor of the liver, and perhaps of the foot also, but nevertheless the liver might also in this case be previously inflamed, as observed in Sect. XXIV. 2. 8. Now as the membranes of the joints of the feet suffer greater variations of heat and cold than the membranes of the liver, and are more habituated to extension and contraction than other parts of the skin in their vicinity; I suppose them to be more mobile, that is, more liable to run into extremes of exertion or quiescence; and are thence more susceptible of inflammation, than such parts as are less exposed to great variations of heat and cold, or of extension and contraction. When a stone presses into the sphincter of the bladder, the glans penis is affected with greater pain by sympathy, owing to its greater sensibility, than the sphincter of the bladder; and when this pain commences, that of the sphincter ceases, when the stone is not too large, or pushed too far into the urethra. Thus when the membrane, which covers the ball of the great toe, sympathizes with some membranous part of a torpid or inflamed liver; this membrane of the toe falls into that kind of action, whether of torpor or inflammation, with greater energy, than those actions excited in the diseased liver; and when this new torpor or inflammation commences, that with which it sympathises ceases; which I believe to be a general law of associated inflammations. The paroxysms of the gout would seem to be catenated with solar influence, both in respect to their larger annual periods, and to their diurnal periods--See Sect. XXXVI. 3. 6.--as the former occur about the same season of the year, and the latter commence about an hour before sun-rise; nevertheless the annual periods may depend on the succession of great vicissitudes of cold and heat, and the diurnal ones on our increased sensibility to internal sensations during sleep, as in the fits of asthma, and of some epilepsies. See Sect. XVIII. 15. In respect to the pre-remote cause or disposition to the gout, there can be no doubt of its individually arising from the potation of fermented or spirituous liquors in this country; whether opium produces the same effect in the countries, where it is in daily use, I have never been well informed. See Sect. XXI. 10, where this subject is treated of; to which I have to add, that I have seen some, and heard of others, who have moderated their paroxysms of gout, by diminishing the quantity of fermented liquors, which they had been accustomed to; and others who, by a total abstinence from fermented liquors, have entirely freed themselves from this excruciating malady; which otherwise grows with our years, and curtails or renders miserable the latter half, or third, of the lives of those, who are subject to it. The remote cause is whatever induces temporary torpor or weakness of the system; and the proximate cause is the inirritability, or defective irritation, of some part of the system; whence torpor and consequent inflammation. The great Sydenham saw the beneficial effects of the abstinence from fermented liquors in preventing the gout, and adds, "if an empiric could give small-beer only to gouty patients as a nostrum, and persuade them not to drink any other spirituous fluids, that he might rescue thousands from this disease, and acquire a fortune for his ingenuity." Yet it is to be lamented, that this accurate observer of diseases had not resolution to practise his own prescription, and thus to have set an example to the world of the truth of his doctrine; but, on the contrary, recommends Madeira, the strongest wine in common use, to be taken in the fits of the gout, to the detriment of thousands; and is said himself to have perished a martyr to the disease, which he knew how to subdue! As example has more forcible effect: than simple assertion, I shall now concisely relate my own case, and that of one of my most respected friends. E. D. was about forty years of age, when he was first seized with a fit of the gout. The ball of his right great toe was very painful, and much swelled and inflamed, which continued five or six days in spite of venesection, a brisk cathartic with ten grains of calomel, and the application of cold air and cold water to his foot. He then ceased to drink ale or wine alone; confining himself to small beer, or wine diluted with about thrice its quantity of water. In about a year he suffered two other fits of the gout, in less violent degree. He then totally abstained from all fermented liquors, not even tasting small-beer, or a drop of any kind of wine; but eat plentifully of flesh-meat, and all kinds of vegetables, and fruit, using for his drink at meals chiefly water alone, or lemonade, or cream and water; with tea and coffee between them as usual. By this abstinence from fermented liquors he kept quite free from the gout for fifteen or sixteen years; and then began to take small-beer mixed with water occasionally, or wine and water, or perry and water, or cyder and water; by which indulgence after a few months he had again a paroxysm of gout, which continued about three days in the ball of his toe; which occasioned him to return to his habit of drinking water, and has now for above twenty years kept in perpetual health, except accidental colds from the changes of the seasons. Before he abstained from fermented or spirituous liquors, he was frequently subject to the piles, and to the gravel, neither of which he has since experienced. In the following case the gout was established by longer habit and greater violence, and therefore required more cautious treatment. The Rev. R. W. was seized with the gout about the age of thirty-two, which increased so rapidly that at the age of forty-one he was confined to his room seven months in that year; he had some degree of lameness during the intervals, with chalky swellings of his heels and elbows. As the disease had continued so long and so violently, and the powers of his digestion were somewhat weakened, he was advised not entirely to leave off all fermented liquors; and as small-beer is of such various strength, he was advised to drink exactly two wine glasses, about four ounces, of wine mixed with three or four times its quantity of water, with or without lemon and sugar, for his daily potation at dinner, and no other fermented liquor of any kind; and was advised to eat flesh-meat with any kind of boiled vegetables, and fruit, with or without spice. He has now scrupulously continued this regimen for above five years, and has had an annual moderate gouty paroxysm of a few weeks, instead of the confinement of so many months, with great health and good spirits during the intervals. The following is a more particular account of the history of this case; being part of a letter which Mr. Wilmot wrote on that subject at my entreaty. "I entered into the army with an excellent constitution at the age of fifteen. The corps I served in was distinguished by its regularity, that is, the regular allowance of the mess was only one pint of wine per man each day; unless we had company to dine with us; then, as was the general custom of the time, the bottle circulated without limit. This mode of living, though by no means considered as excess for men, was certainly too great for a youth of my age. This style of living I continued, when with the regiment, till the latter end of the year 1769, when I had the misfortune to sleep in a damp bed at Sheffield on a journey to York, but arrived there before I felt the ill effects of it. I was then seized with a violent inflammatory rheumatism with great inflammation of my eyes, and was attended by Dr. Dealtry; so violent was the disorder, that I was bled for it eight times in less than a fortnight; and was three months, before I could consider my health perfectly re-established. Dr. Dealtry told me, that I should be subject to similar attacks for many years; and that he had no doubt, from the tendency he found in my habit to inflammation, that, when I was farther advanced in life, I should change that complaint for the gout. He predicted truly; for the three succeeding winters I had the same complaint, but not so violently; the fourth winter I escaped, and imputed my escape to the continuance of cold bathing during the whole of that winter; after that I never escaped it, till I had a regular and severe fit of the gout: after the first attack of rheumatic fever I was more abstemious in my manner of living, though when in company I never subjected myself to any great restraint. In the year 1774 I had quitted the army, and being in a more retired situation, was seldom led into any excess; in 1776 and 1777 I was in the habit of drinking a good deal of wine very frequently, though not constantly. After that period till the year 1781, I drank a larger quantity of wine regularly, but very seldom to any degree of intoxication. I lived much at that time in the society of some gentlemen, who usually drank nearly a bottle of wine daily after dinner. I must here however observe, that at no part of my life was I accustomed to drink wine in an evening, and very seldom drank any thing more than a single half-pint glass of some sort of spirits diluted with much water. Till the year 1781 I had always been accustomed to use very violent and continued exercise on horseback; in the winter months I pursued all field diversions, and in the summer months I rode frequent and long journeys; and with this exercise was liable to perspire to great excess; besides which I was subject to very profuse night-sweats, and had frequently boils break out all over me, especially in the spring and autumn; for which I took no medicine, except a little flour of sulphur with cream of tartar in honey. "You will observe I bring every thing down to the date of 1781. In the month of October in that year, when I was just entered into the thirty-second year of my age, I had the first attack of gout; that fit was very severe, and of many weeks continuance. I now determined upon a more abstemious method of living, in respect to wine; and indeed the society, in which I had before been accustomed to live, being considerably changed, I had less frequent temptations to excess. From this time I enjoyed the most perfect good state of health till August 1784, when I had my second attack of gout. I never perfectly recovered from this attack through the succeeding winter, and in March 1785 was advised to try the Bath waters, and drank them under the direction of one of the faculty of that place. I was there soon seized with a fever, and a slight attack of gout in one knee. I should observe, that when I set out from home, I was in a weak and low state, and unequal to much fatigue; as appeared by my having a fainting fit one day on the road, after having travelled only about fifty miles; in the course of the summer I had two or three more slight attacks of gout of less consequence, till the month of October; when I was afflicted with it all over me in such a manner, as to be without the possibility of the least degree of removal for some days; and was about two months without being able to get into the air. This was the severest attack I had then experienced; though I have since had several equally severe. In the course of this summer I had a fall with my horse; and soon after it, having discovered an enlargement on one elbow, I concluded I had hurt it at that time; but in the course of this last attack having a similar enlargement on the other elbow, I found my mistake, and that they were collections of gouty matter; these increased to the size of pullet's eggs, and continue in that state. I had soon after similar enlargements on my heels; the right heel being severely bruised, I was under the necessity of having it lanced, and a large quantity of chalky matter was discharged from it; and have since that time frequently had chalky matter taken from it, and sometimes small bits of apparently perfect chalk. My right hand soon was afflicted in the same way, and I have scarcely a joint on those fingers now in a natural state. My left hand has escaped tolerably well. After this last attack (viz. October 1785), I had two or three slight attacks before the month of June 1787, when I had a very severe intermittent fever; from that time I continued very well till the latter end of the year, when I began to feel the gout about me very much, but was not confined by it. I was in this state advised to try what is called the American Recipe (gum guaiacum and nitre dissolved in spirits); it had apparently been of essential service to a friend of mine, who from the inability to walk a mile for some years, was believed to be restored by the use of this medicine to a good state of health, so as to walk ten miles a day. In addition to this medicine I drank, as my common beverage with my meals, spruce beer. I had so high an opinion of this medicine in the gout, and of spruce beer as an antiscorbutic, that I contemplated with much satisfaction, and with very little doubt, the perfect restoration of my health and strength; but I was miserably deceived; for in September 1788 I was seized with the gout in a degree that none but arthritics, and indeed but few of those, can easily conceive. From this time till August 1789 I scarcely ever passed a comfortable day; seven months of this time I had been confined, my health seemed much impaired, my strength was diminished, and my appetite almost gone. In this state my friends pressed me to consult you. I was unwilling for some time to do it, as I had lost all hope of relief; however, when I had determined to apply to you, I likewise determined to give up every prejudice of my own respecting my case, and to adhere most strictly to your advice. On the 20th of August 1789 I consulted you, on the 25th I entered upon the regimen, which you prescribed, and which was as follows. "Drink no malt liquor on any account. Let your beverage at dinner consist of two glasses of wine diluted with three half-pints of water. On no account drink any more wine or spirituous liquors in the course of the day; but, if you want more liquid, take cream and water, or milk and water, or lemonade, with tea, coffee, chocolate. Use the warm bath twice a week for half an hour before going to bed, at the degree of heat which is most grateful to your sensations. Eat meat constantly at dinner, and with it any kind of tender vegetables you please. Keep the body open by two evacuations daily, if possible without medicine, if not take the size of a nutmeg of lenitive electuary occasionally, or five grains of rhubarb every night. Use no violent exercise, which may subject yourself to sudden changes from heat to cold; but as much moderate exercise as may be, without being much fatigued or starved with cold. Take some supper every night; a small quantity of animal food is preferred; but if your palate refuses this, take vegetable food, as fruit pie, or milk; something should be eaten, as it might be injurious to you to fast too long." To the whole of this I adhered most scrupulously, and soon found my appetite improve, and with it my strength and spirits. I had in December a fevere attack, and two or three slight ones in the course of twelve months; but the improvement in the general state of my health induced me to persevere. On the 18th of August 1790 I had another severe attack, but it went off easier than before, and I soon recovered sufficiently to go to Buxton, which you advised me to, and from which I reaped great benefit; nevertheless on the 29th of December I had a slight attack in comparison of some that I had before experienced, and from that time I was free from gout, and enjoyed my health perfectly well till the fourth week in October 1791; from that till the third week in October 1792; from that till the third week in October 1793; and from that till June 1794. From what happened for the last three years I dreaded the month of October; but I escaped then, and have enjoyed my health most perfectly ever since till within the last week, that I have had a slight attack in one knee, which is nearly gone, without any symptom to lead me to suppose that it will go further. "I adhered to your advice most scrupulously for the first year; and in regard to the not drinking malt liquor, and taking only the two glasses of wine with water, I have never deviated but two days; and then the first day I only drank one glass of ale and one glass of Champaigne; on the second only one glass of Champaigne. With regard to the warm bath, I only use it now when I have gouty symptoms upon me, and in such situations I find it of infinite service; and in other respects I continue to live according to your direction. "Many persons have laughed at the idea of my perseverance in a system, which has not been able to _cure_ the gout after five years trial; but such persons are either ignorant of what I before suffered, or totally unacquainted with the nature of the disorder. Under the blessing of Providence, by an adherence to your advice, I am reaping all the benefit you flattered me I might expect from it, viz. my attacks less frequent, my sufferings less acute, and an improvement in the general state of my health. "I have been particular in this account of myself at your request, and am, Sir, &c. MORLEY, near DERBY, February 10th, 1795. ROBERT WILMOT." There are situations nevertheless in which a paroxysm of gout has been believed to be desirable, as relieving the patient from other disagreeable diseases, or debilities, or sensations. Thus when the liver is torpid, a perpetual uneasiness and depression of spirits occur; which a fit of gout is supposed to cure by a metastasis of the disease. Others have acquired epileptic fits, probably from the disagreeable sensation of a chronically inflamed liver; which they suppose the pain and inflammation of gout would relieve. When gouty patients become much debilitated by the progress of the disease, they are liable to dropsy of the chest, which they suppose a fit of the gout would relieve. But in all these cases the attempt to procure a paroxysm of gout by wine, or aromatics, or volatiles, or blisters, or mineral waters, seldom succeeds; and the patients are obliged to apply to other methods of relief adapted to their particular cases. In the two former situations small repeated doses of calomel, or mercurial unction on the region of the liver may succeed, by giving new activity to the vessels of the liver, either to secrete or to absorb their adapted fluids, and thus to remove the cause of the gout, rather than to promote a fit of it. In the last case the tincture of digitalis, and afterwards the class of sorbentia, must be applied to. M. M. In young strong patients the gout should be cured by venesection and cathartics and diluents, with poultices externally. But it has a natural crisis by producing calcareous matter on the inflamed membrane, and therefore in old enfeebled people it is safest to wait for this crisis, attending to the natural evacuations and the degree of fever; and in young ones, where it is not attended with much fever, it is customary and popular not to bleed, but only to keep the body open with aloes, to use gentle sudorifics, as neutral salts, and to give the bark at the decline of the fit; which is particularly useful where the patient is much debilitated. See Arthritis ventriculi, Class I. 2. 4. 6. and Sect. XXV. 17. When there is not much fever, and the patient is debilitated with age, or the continuance of the disease, a moderate opiate, as twenty drops of tincture of opium, or one grain of solid opium, may be taken every night with advantage. Externally a paste made with double the quantity of yeast is a good poultice; and booterkins made with oiled silk, as they confine the perspirable matter, keep the part moist and supple, and thence relieve the pain like poultices. The only safe way of moderating the disease is by an uniform and equal diminution, or a total abstinence from fermented liquors, with the cautions directed in Sect. XII. 7. 8. The continued use of strong bitters, as of Portland's powder, or bark, has been frequently injurious, as spoken of in the Materia Medica, Art. IV. 2. 11. One of my acquaintance, who was much afflicted with the gout, abstained for about half a year from beer and wine; and not having resolution to persist, returned to his former habits of potation in less quantity; and observed that he was then for one winter stronger and freer from the gout than usual. This however did not long continue, as the disease afterwards returned with its usual or increased violence. This I think is a circumstance not unlikely to occur, as opium has a greater effect after its use has been a while intermitted; and the debility or torpor, which is the cause of gout, is thus for a few months prevented by the greater irritability of the system, acquired during the lessened use of fermented liquor. For the same reason an ounce of spirituous tincture of guaiacum, or of bark, is said to have for some time prevented returns of the gout; which has afterwards, like all other great stimuli when long continued, been succeeded by greater debility, and destroyed the patient. This seems to have been exemplified in the case of the ingenious Dr. Bown, see Preface to his Elementa Medicinæ; he found temporary relief from the stimulus of wine, regardless of its future effects. 16. _Rheumatismus._ Acute rheumatism. There is reason to suspect, that rheumatic inflammations, like the gouty ones, are not a primary disease; but that they are the consequence of a translation of morbid action from one part of the system to another. This idea is countenanced by the frequent change of place of rheumatic-like gouty inflammations, and from their attacking two similar parts at the same time, as both ankles and both wrists, and these attacks being in succession to each other. Whereas it is not probable that both feet or both hands should at the same time be equally exposed to any external cause of the disease, as to cold or moisture; and less so that these should occur in succession. Lastly, from the inflammatory diathesis in this disease being more difficult to subdue, and more dangerous in event, than other common inflammations, especially to pregnant women, and in weak constitutions. From this idea of the rheumatism being not a primary disease, like the gout, but a transferred morbid action owing to the previous torpor of some other part of the system, we perceive why it attacks weak people with greater pertinacity than strong ones; resisting or recurring again and again after frequent evacuations, in a manner very different from primary inflammations; because the cause is not removed, which is at a distance from the seat of the inflammation. This also accounts for rheumatic inflammations so very rarely terminating in suppuration, because like the gout the original cause is not in the inflamed part, and therefore does not continue to act after the inflammation commences. Instead of suppuration in this disease, as well as in the gout, a quantity of mucus or coagulable lymph is formed on the inflamed membrane; which in the gout changes into chalkstones, and in the rheumatism is either reabsorbed, or lies on the membrane, producing pains on motion long after the termination of the inflammation, which pains are called chronic rheumatism. The membranes, which have thus been once or repeatedly inflamed, become less mobile, or less liable to be affected by sympathy, as appears by the gout affecting new parts, when the joints of the foot have been frequently inflamed by it; hence as the cause of the inflammation does not exist in the inflamed part, and as this part becomes less liable to future attacks, it seldom suppurates. Secondly, when rheumatism affects the muscles of the chest, it produces symptoms similar to pleurisy, but are distinguished from that by the patient having previously suffered rheumatic affections in other parts, and by the pertinacity or continuance of the inflammatory state of the patient, this should be termed pleurodyne rheumatica. Thirdly, when rheumatic inflammation affects the bowels, it produces a disease very different from enteritis, or common inflammation of the bowels, and should be termed enteralgia rheumatica. The pain is less than in enteritis, and the disease of longer continuance, with harder pulse, and the blood equally sizy. It is attended with frequent dejections, with much mucus, and previous griping pains, but without vomiting; and differs perhaps from dysentery from its not being attended with bloody stools, and not being infectious. Fourthly, there is another kind of rheumatism attended with debility, which suppurates, and should be termed rheumatismus suppurans. It is generally believed to be the gout, till suppuration takes place on the swelled joint; and, as the patient sinks, there are sloughs formed over the whole mouth; and he seems to be destroyed by inflammation or gangrene of the mucous membranes. I have twice seen this disease in patients about sixty. Some other diseases are erroneously called rheumatic, as hemicrania, and odontalgia. See Sect. XXVI. 3. M.M. In the three former kinds venesection repeatedly. Cathartics. Antimonials. Diluents. Neutral salts. Oil. Warm bath. Afterwards the bark. Opium with or without ipecacuanha; but not till the patient is considerably weakened. Sweats forced early in the disease do injury. Opium given early in the disease prolongs it. In the last kind, gentle stimulants, as wine and water, mucilage, sorbentia. The following is a case of suppurative rheumatism. Mr. F----, about sixty, was supposed to have the gout in his hand, which however suppurated, and it was then called the suppurative rheumatism. He had lived rather intemperately in respect to wine, and was now afflicted with a tendency to inflammation of the mucous membranes. As he lay on the bed half resupine, propped up with pillows, and also slept in that posture, his lower jaw dropped by its own weight, when the voluntary power of the muscles was suspended. The mucus of his mouth and throat became quite dry, and at length was succeeded with sloughs; this was a most distressing circumstance to him, and was in vain endeavoured to be relieved by supporting his jaw by slender steel springs fixed to his night-cap, and by springs of elastic gum. The sloughs spread and seemed to accelerate his death. See Class I. 1. 3. 2. 17. _Erysipelas._ The erysipelas differs from the zona ignea, and other species of herpes, in its being attended with fever, which is sometimes of the sensitive irritated or inflammatory kind, with strong and full pulse; and at other times with weak pulse and great inirritability, as when it precedes or attends mortifications. See Class II. 1. 3. 2. Like the zona ignea above described, it seems to be a secondary disease, having for its primary part the torpor or inflammation of some internal or distant membrane, as appears from its so frequently attending wounds; sometimes spreading from issues over the whole limb, or back, by sympathy with a tendon or membrane, which is stimulated by the pease in them. In its more violent degree I suppose that it sympathizes with some extensive internal membranes, as of the liver, stomach, or brain. Another reason, which countenances this idea, is, that the inflammation gradually changes its situation, one part healing as another inflames; as happens in respect to more distant parts in gout and rheumatism; and which seems to shew, that the cause of the disease is not in the same place with the inflammation. And thirdly, because the erysipelas of the face and head is liable to affect the membranes of the brain; which were probably in these cases the original or primary seat of the disease; and lastly, because the fits of erysipelas, like those of the gout, are liable to return at certain annual or monthly periods, as further treated of in Class II. 1. 3. 2. Many cases of erysipelas from wounds or bruises are related in Default's Surgical Journal, Vol. II. in which poultices are said to do great injury, as well as oily or fatty applications. Saturnine solutions were sometimes used with advantage. A grain of emetic tartar given to clear the stomach and bowels, is said to be of great service. 18. _Testium tumor in gonorrhoea._ Mr. Hunter in his Treatise on the Venereal Disease observes, that the tumor of the testes in gonorrhoea arises from their sympathy with the inflammation of the urethra; and that they are not similar to the actions arising from the application of venereal matter, whether by absorption or otherwise; as they seldom or never suppurate; and when suppuration happens, the matter produced is not venereal. Treatise on Venereal Disease, p. 53. 19. _Testium tumor in parotidite._ The sympathy between some parts about the throat and the genitals has been treated of in Class IV. 1. 2. 7. The swelling of the testes, when that of the parotis subsides, seems to arise from the association of successive action; as the tension of the penis in hydrophobia appears to arise from the previous synchronous associations of the sensitive motions of these parts; but the manner of the production of both these associations is yet very obscure. In women a swelling of the breasts often succeeds the decline of the mumps by another wonderful sympathy. See Class IV. 1. 2. 7. and I. 1. 2. 15. In many persons a delirium succeeds the swelling of the parotis, or the subsequent ones of the testes or breasts; which is sometimes fatal, and seems to arise from a sympathy of successive action, and not of synchronous action, of the membranes of the brain with those of the parotide glands. Sometimes a stupor comes on instead of this delirium, which is relieved by fomenting the shaved head for an hour or two. See Class II. 1. 3. 4. * * * * * ORDO I. _Increased Associate Motions._ GENUS III. _Catenated with Voluntary Motions_ SPECIES. 1. _Deglutitio invita._ When any one is told not to swallow his saliva, and that especially if his throat be a little sore, he finds a necessity of immediately swallowing it; and this the more certainly, the more he voluntarily endeavours not to do so. In this case the voluntary power exerted by our attention to the pharinx renders it more sensible to irritation, and therefore occasions it to be more frequently induced to swallow the saliva. Here the irritation induces a volition to swallow it, which is more powerful than the desire not to swallow it. See XXIV. 1. 7. So in reverie, when the voluntary power was exerted on any of the senses, as of sight or taste, the objects of those senses became perceived; but not otherwise. Sect. XIX. 6. This is a troublesome symptom in some sore throats. M. M. Mucilage, as sugar and gum arabic. Warm water held in the mouth frequently, as a fomentation to the inflamed throat. 2. _Nictitatio invita._ Involuntary winking with the eye-lids, and twitchings of the face, are originally induced by an endeavour to relieve some disagreeable sensations about inflamed eyes, as the dazzling of light; and afterwards these motions become catenated with other motions or sensations, so as not to be governed by the will. Here the irritation first produces a volition to wink, which by habit becomes stronger than the anti-volition not to wink. This subject is rendered difficult from the common acceptation of the word, volition, including previous deliberation, as well as the voluntary exertion, which succeeds it. In the volitions here spoken of there is no time for deliberation or choice of objects, but the voluntary act immediately succeeds the sensation which excites it. M. M. Cover the affected parts with a sticking plaster or a blister. Pass a fine needle and thread through a part of the skin over the muscle, which moves, and attach the other end of the thread by a sticking plaster to a distant part. An issue behind the ear. To practise daily by a looking-glass to stop the motions with the hand. See the cure of a case of the leaping of a muscle of the arm, Sect. XVII. 1. 8. See Convulsio debilis, Class III. 1. 1. 5. 3. _Risus invitus._ Involuntary laughter. When the pleasure arising from new combinations of words and ideas, as in puns; or of other circumstances, which are so trivial, as to induce no voluntary exertion to compare or consider their present importance or their future consequence; the pleasure is liable to rise into pain; that is, the ideas or sensual motions become exerted too violently for want of some antithetistic ideas; in the same manner as those muscles, which have weak antagonists, as those of the calf of the leg, are liable to fall into cramp or painful contraction. In this situation a scream is begun to relieve this pain of ideas too violently exerted, which is stopped again soon, as explained in Sect. XXXIV. 1. 4. and Class III. 1. 1. 4. and IV. 2. 3. 3. The pain, into which this pleasure rises, which would excite the scream of laughter, has been felt forcibly by every one; when they have been under such circumstances, as have induced them to restrain it by a counter-volition; till at length the increased associate motions produce so much pain as to overcome the counter-volition, and the patient bursts out into indecent laughter, contrary to his will in the common acceptation of that word. 4. _Lusus digitorum invitus._ An awkward playing with the fingers in speaking in public. These habits are began through bashfulness, and seem rather at first designed to engage the attention in part, and thus prevent the disagreeable ideas of mauvaise hont; as timorous boys whistle, when they are obliged to walk in the dark; and as it is sometimes necessary to employ raw soldiers in perpetual manoeuvres, as they advance to the first charge. 5. _Unguium morsiuncula invita._ Biting the nails is a depraved habit arising from similar causes as those of the last article. M. M. Dip the fingers in solution of aloes. 6. _Vigilia invita._ Watchfulness, where the person wishes, and endeavours to fall asleep, properly belongs to this place, as the wish or volition to sleep prevents the desired effect; because sleep consists in an abolition of volition. See Class III. 1. 2. 3. * * * * * ORDO I. _Increased Associate Motions._ GENUS IV. _Catenated with External Influences._ SPECIES. 1. _Vita ovi._ Life of an egg. The eggs of fowls were shewn by Mr. J. Hunter to resist the freezing process in their living state more powerfully, than when they were killed by having the yolk and white shook together. Philos. Trans. It may be asked, does the heat during the incubation of eggs act as a stimulus exciting the living principle into activity? Or does it act simply as a causa sine quâ non, as an influence, which penetrating the mass, removes the particles of it to a greater distance from each other, so as to allow their movement over each other, in the same manner as heat is conceived to produce the fluidity of water; not by stimulus, but by its penetrating influence? Or may elementary heat in its uncombined state be supposed to act only as an influence necessary to life in its natural quantity; whence torpor and death follows the eduction of it from the body; but in its increased state above what is natural, or usual, that it acts as a stimulus; which we have a sense to perceive; and which excites many parts of the system into unnatural action? See Class IV. 1. 1. C. 2. _Vita hiemi-dormientium._ The torpor of insects, and birds, and quadrupeds, during the cold season, has been called sleep; but I suppose it must differ very much from that state of animal life, since not only all voluntary power is suspended, but sensation and vascular motion has ceased, and can only be restored by the influence of heat. There have been related instances of snails, which have recovered life and motion on being put into water after having experienced many years of torpidity, or apparent death, in the cabinets of the curious. Here the water as well as the heat are required not only as a stimulus, but as a causa sine quâ non of fluidity and motion, and consequent life. 3. _Pullulatio arborum._ The annual revivescence of the buds of trees seems not only to be owing to the influence of the returning warmth of the spring, but also to be catenated with solar gravitation; because seeds and roots and buds, which are analogous to the eggs of animals, put forth their shoots by a less quantity of heat in spring, than they had undergone in the latter part of autumn, which may however be ascribed to their previous torpid state, and consequent accumulation of sensorial power, or irritability; as explained in Botanic Garden, Part II. Cant. I. l. 322. note. Other circumstances, which countenance the idea, that vegetation is affected by solar gravitation, as well as by heat, may be observed in the ripening of the seeds of plants both in those countries where the summers are short, and in those where they are long. And by some flowers closing their bells at noon, or soon after; and hence seem to sleep rather at solar diurnal periods, than from the influence of cold, or the deficiency of light. 4. _Orgasmatis venerei periodus._ The venereal orgasm of birds and quadrupeds commences or returns about the vernal or autumnal equinoxes, and thence seems in respect to their great periods to be governed by solar influence. But if this orgasm be disappointed of its object, it is said to recur at about monthly periods, as observed in mares and bitches in this respect resembling the female catamenia. See Sect. XXXVI. 2. 3. and Sect. XVI. 13. 5. _Brachii concussio electrica._ The movement of the arm, even of a paralytic patient, when an electric shock is passed through it, is owing to the stimulus of the excess of electricity. When a piece of zinc and silver, each about the size of a crown-piece, are placed one under the upper lip, and the other on the tongue, so as the outer edges may be brought into contact, there is an appearance of light in the eyes, as often as the outer edges of these metals are brought into contact or separated; which is another instance of the stimulus of the passage of electric shocks through the fibres of the organs of sense, as well as through the muscular fibres. See Sect. XII. 1. 1. and first addit. note to Vol. I. of this work. But in its natural state electricity seems only to act as an influence on animal and vegetable bodies; of the salutary or injurious effects of which we have yet no precise knowledge. Yet if regular journals were kept of the variations of atmospheric electricity, it is probable some discoveries of its influence on our system might in time be discovered. For this purpose a machine on the principle of Mr. Bennet's electric doubler might be applied to the pendulum of a clock, so as to manifest, and even to record the daily or hourly variations of aerial electricity. Which has already been executed, and applied to the pendulum of a Dutch wooden clock, by Mr. Bennet, curate of Wirksworth in Derbyshire. Besides the variations of the degree or kind of atmospheric electricity, some animals, and some men, seem to possess a greater power of accumulating this fluid in themselves than others. Of which a famous history of a Russian prince was lately published; who, during the clear and severe frosts of that country, could not move himself in bed without luminous corruscations. Such may have been the case of those people, who have been related to have taken fire spontaneously, and to have been reduced to ashes. The electric concussion from the gymnotus electricus, and torpedo, are other instances of the power of the animal system to accumulate electricity, as in these it is used as a weapon of defence, or for the purpose of taking their prey. Some have believed that the accumulation or passage of the magnetic fluid might affect the animal system, and have asserted that the application of a large magnet to an aching tooth has quickly effected a cure. If this experiment is again tried in odontalgia, or hemicrania, the painful membrane of the tooth or head should be included between the south and north poles of a horse-shoe magnet, or between the contrary poles of two different magnets, that the magnetism may be accumulated on the torpid part. 6. _Oxygenatio sanguinis._ The variation of the quantity of oxygen gas existing in the atmosphere must affect all breathing animals; in its excess this too must be esteemed a stimulus; but in its natural quantity would seem to act as an influence, or cause, without which, animal life cannot exist even a minute. It is hoped that Dr. Beddoes's plan for a pneumatic infirmary, for the purpose of putting this and various other airs to the test of experiment, will meet with public encouragement, and render consumption, asthma, cancer, and many diseases conquerable, which at present prey with unremitted devastation on all orders and ages of mankind. 7. _Humectatio corporis._ Water, and probably the vapour of water dissolved or diffused in the atmosphere, unites by mechanical attraction with the unorganized cuticle, and softens and enlarges it; as may be seen in the loose and wrinkled skin of the hands of washerwomen; the same probably occurs to the mucous membrane of the lungs in moist weather; and by thickening it increases the difficulty of respiration of some people, who are said to be asthmatical. So far water may be said to act as an influx or influence, but when it is taken up by the mouths of the absorbent system, it must excite those mouths into action, and then acts as a stimulus. There appears from hence to be four methods by which animal bodies are penetrated by external things. 1. By their stimulus, which induces the absorbent vessels to imbibe them. 2. By mechanical attraction, as when water softens the cuticle. 3. By chemical attraction, as when oxygen passes through the membranes of the air-vessels of the lungs, and combines with the blood. And lastly, by influx without mechanical attraction, chemical combination, or animal absorption, as the universal fluids of heat, gravitation, electricity, magnetism, and perhaps of other ethereal fluids yet unknown. * * * * * ORDO II. _Decreased Associate Motions._ GENUS I. _Catenated with Irritative Motions._ As irritative muscular motions are attended with pain, when they are exerted too weakly, as well as when they are exerted too strongly; so irritative ideas become attended with sensation, when they are exerted too weakly, as well as when they are exerted too strongly. Which accounts for these ideas being attended with sensation in the various kinds of vertigo described below. There is great difficulty in tracing the immediate cause of the deficiences of action of some links of the associations of irritative motions; first, because the trains and tribes of motions, which compose these links, are so widely extended as to embrace almost the whole animal system; and secondly, because when the first link of an associated train of actions is exerted with too great energy, the second link by reverse sympathy may be affected with torpor. And then this second link may transmit, as it were, this torpor to a third link, and at the same time regain its own energy of action; and it is possible this third link may in like manner transmit its torpor to a fourth, and thus regain its own natural quantity of motion. I shall endeavour to explain this by an example taken from sensitive associated motions, as the origin of their disturbed actions is more easily detected. This morning I saw an elderly person, who had gradually lost all the teeth in his upper jaw, and all of the under except three of the molares; the last of these was now loose, and occasionally painful; the fangs of which were almost naked, the gums being much wasted both within and without the jaw. He is a man of attentive observation, and assured me, that he had again and again noticed, that, when a pain commenced in the membranes of the alveolar process of the upper jaw opposite to the loose tooth in the under one (which had frequently occurred for several days past), the pain of the loose tooth ceased. And that, when the pain afterwards extended to the ear and temple on that side, the pain in the membranes of the upper jaw ceased. In this case the membranes of the alveolar process of the upper jaw became torpid, and consequently painful, by their reverse sympathy with the too violent actions of the inflamed membranes of the loose tooth; and then by a secondary sympathy the membranes about the ear and temple became torpid, and painful; and those of the alveolar process of the upper jaw regained their natural quantity of action, and ceased to be painful. A great many more nice and attentive observations are wanted to elucidate these curious circumstances of association, which will be found to be of the greatest importance in the cure of many diseases, and lead us to the knowledge of fever. SPECIES. 1. _Cutis frigida pransorum._ Chillness after dinner frequently attends weak people, or those who have been exhausted by exercise; it arises from the great expenditure of the sensorial power on the organs of digestion, which are stimulated into violent action by the aliment; and the vessels of the skin, which are associated with them, become in some measure torpid by reverse sympathy; and a consequent chillness succeeds with less absorption of atmospheric moisture. See the subsequent article. 2. _Pallor urinæ pransorum._ The paleness of urine after a full meal is an instance of reverse association; where the secondary part of a train of associate motions acts with less energy in consequence of the greater exertions of the primary part. After dinner the absorbent vessels of the stomach and intestines are stimulated into greater action, and drink up the newly taken aliment; while those, which are spread in great number on the neck of the bladder, absorb less of the aqueous part of the urine than usual, which is therefore discharged in a more dilute state; and has been termed crude by some medical writers, but it only indicates, that so great a proportion of the sensorial power is expended on digestion and absorption of the aliment, that other parts of the system act for a time with less energy. See Class IV. I. 1. 6. 3. _Pallor urinæ a frigore cutaneo._ There is a temporary discharge of pale water, and a diarrhoea, induced by exposing the skin to the cold air; as is experienced by boys, who strip themselves before bathing. In this case the mouths of the cutaneous lymphatics become torpid by the subduction of their accustomed degree of heat, and those of the bladder and intestines become torpid by direct sympathy; whence less of the thinner part of the urinary secretion, and of the mucus of the intestines, is reabsorbed. See Sect. XXIX. 4. 6. This effect of suddenly cooling the skin by the aspersion of cold water has been used with success in costiveness, and has produced evacuations, when other means have failed. When young infants are afflicted with griping joined with costiveness, I have sometimes directed them to be taken out of a warm bed, and carried about for a few minutes in a cool room, with almost instant relief. 4. _Pallor ex ægritudine._ When sickness of stomach first occurs, a paleness of the skin attends it; which is owing to the association or catenation between the capillaries of the stomach and the cutaneous ones; which at first act by direct sympathy. But in a short time there commences an accumulation of the sensorial power of association in the cutaneous capillaries during their state of inactivity, and then the skin begins to glow, and sweats break out, from the increased action of the cutaneous glands or capillaries, which is now in reverse sympathy with those of the stomach. So in continued fevers, when the stomach is totally torpid, which is known by the total aversion to solid food, the cutaneous capillaries are by reverse sympathy in a perpetual state of increased activity, as appears from the heat of the skin. 5. _Dyspnoea a balneo frigido._ The difficulty of breathing on going up to the middle in cold water is owing to the irritative association or catenation of the action of the extreme vessels of the lungs with those of the skin. So that when the latter are rendered torpid or inactive by the application of sudden cold, the former become inactive at the same time, and retard the circulation of the blood through the lungs, for this difficulty of breathing cannot be owing to the pressure of the water impeding the circulation downwards, as it happens equally by a cold shower-bath, and is soon conquered by habitual immersions. The capillaries of the skin are rendered torpid by the subduction of the stimulus of heat, and by the consequent diminution of the sensorial power of irritation. The capillaries of the lungs are rendered torpid by the diminution of the sensorial power of association, which is now excited in less quantity by the lessened actions of the capillaries of the skin, with which they are catenated. So that at this time both the cutaneous and pulmonary capillaries are principally actuated, as far as they have any action, by the stimulus of the blood. But in a short time the sensorial powers of irritation, and of association, become accumulated, and very energetic action of both these membranes succeed. Which thus resemble the cold and hot fit of an intermittent fever. 6. _Dyspepsia a pedibus frigidis._ When the feet are long cold, as in riding in cold and wet weather, some people are very liable to indigestion and consequent heart-burn. The irritative motions of the stomach become torpid, and do their office of digestion imperfectly, in consequence of their association with the torpid motions of the vessels of the extremities. Fear, as it produces paleness and torpidity of the skin, frequently occasions temporary indigestion in consequence of this association of the vessels of the skin with those of the stomach; as riding in very bad roads will give flatulency and indigestion to timorous people. A short exposure to cold air increases digestion, which is then owing to the reverse sympathy between the capillary vessels of the skin, and of the stomach. Hence when the body is exposed to cold air, within certain limits of time and quantity of cold, a reverse sympathy of the stomach and the skin first occurs, and afterwards a direct sympathy. In the former case the expenditure of sensorial power by the skin being lessened, but not its production in the brain; the second link of the association, viz. the stomach, acquires a greater share of it. In the latter case, by the continuation of the deficient stimulus of heat, the torpor becomes extended to the brain itself, or to the trunks of the nerves; and universal inactivity follows. 7. _Tussis a pedibus frigidis._ On standing with the feet in thawing snow, many people are liable to incessant coughing. From the torpidity of the absorbent vessels of the lungs, in consequence of their irritative associations with those of the skin, they cease to absorb the saline part of the secreted mucus; and a cough is thus induced by the irritation of this saline secretion; which is similar to that from the nostrils in frosty weather, but differs in respect to its immediate cause; the former being from association with a distant part, and the latter from defect of the stimulus of heat on the nostrils themselves. See Catarrhus frigidus, Class I. 2. 3. 3. 8. _Tussis hepatica._ The cough of inebriates, which attends the enlargement of the liver, or a chronical inflammation of its upper membrane, is supposed to be produced by the inconvenience the diaphragm suffers from the compression or heat of the liver. It differs however essentially from that attending hepatitis, from its not being accompanied with fever. And is perhaps rather owing to irritative association, or reverse sympathy, between the lungs and the liver. As occurs in sheep, which are liable to a perpetual dry cough, when the fleuk-worm is preying on the substance of their livers. See Class II. 1. 1. 5. M. M. From half a grain to a grain of opium twice a day. A drachm of mercurial ointment rubbed on the region of the liver every night for eight or ten times. 9. _Tussis arthritica._ Gout-cough. I have seen a cough, which twice recurred at a few years distance in the same person, during his fits of the gout, with such pertinacity and violence as to resist venesection, opiates, bark, blisters, mucilages, and all the usual methods employed in coughs. It was for a time supposed to be the hooping-cough, from the violence of the action of coughing; it continued two or three weeks, the patient never being able to sleep more than a few minutes at once during the whole time, and being propped up in bed with pillows night and day. As no fever attended this violent cough, and but little expectoration, and that of a thin and frothy kind, I suspected the membrane of the lungs to be rather torpid than inflamed, and that the saline part of the mucus not being absorbed stimulated them into perpetual exertion. And lastly, that though the lungs are not sensible to cold and heat, and probably therefore less mobile; yet, as they are nevertheless liable to consent with the torpor of cold feet, as described in Species 6 of this Genus, I suspected this torpor of the lungs to succeed the gout in the feet, or to act a vicarious part for them. 10. _Vertigo rotatoria._ In the vertigo from circumgyration the irritative motions of vision are increased; which is evinced from the pleasure that children receive on being rocked in a cradle, or by swinging on a rope. For whenever sensation arises from the production of irritative motion with less energy than natural, it is of the disagreeable kind, as from cold or hunger; but when it arises from their production with greater energy than natural, if it be confined within certain limits, it is of the pleasurable kind, as by warmth or wine. With these increased irritative motions of vision, I suppose those of the stomach are performed with greater energy by direct sympathy; but when the rotatory motions, which produce this agreeable vertigo, are continued too long, or are too violent, sickness of the stomach follows; which is owing to the decreased action of that organ from its reverse sympathy with the increased actions of the organ of vision. For the expenditure of sensorial power by the organ of vision is always very great, as appears by the size of the optic nerves; and is now so much increased as to deprive the next link of association of its due share. As mentioned in Article 6 of this Genus. In the same manner the undulations of water, or the motions of a ship, at first give pleasure by increasing the irritative motions belonging to the sense of vision; but produce sickness at length by expending on one part of the associated train of irritative actions too much of that sensorial power, which usually served the whole of it; whence some other parts of the train acquire too little of it, and perform their actions in consequence too feebly, and thence become attended with disagreeable sensation. It must also be observed, that when the irritative motions are stimulated into unusual action, as in inebriation, they become succeeded by sensation, either of the pleasurable or painful kind; and thus a new link is introduced between the irritative motions thus excited, and those which used to succeed them; whence the association is either dissevered or much weakened, and thus the vomiting in sea-sickness occurs from the defect of the power of association, rather than from the general deficiency of sensorial power. When a blind man turns round, or when one, who is not blind, revolves in the dark, a vertigo is produced belonging to the sense of touch. A blind man balances himself by the sense of touch, which being a less perfect means of determining small quantities of deviation from the perpendicular, occasions him to walk more carefully upright than those, who balance themselves by vision. When he revolves, the irritative associations of the muscular motions, which were used to preserve his perpendicularity, become disordered by their new modes of successive exertion; and he begins to fall. For his feet now touch the floor in manners or directions different from those they have been accustomed to; and in consequence he judges less perfectly of the situation of the parts of the floor in respect to that of his own body, and thus loses his perpendicular attitude. This may be illustrated by the curious experiment of crossing one finger over the next to it, and feeling of a nut or bullet with the ends of them. When, if the eyes be closed, the nut or bullet appears to be two, from the deception of the sense of touch. In this vertigo from gyration, both of the sense of sight, and of the sense of touch, the primary link of the associated irritative motions is increased in energy, and the secondary ones are increased at first by direct sympathy; but after a time they become decreased by reverse sympathy with the primary link, owing to the exhaustion of sensorial power in general, or to the power of association in particular; because in the last case, either pleasurable or painful sensation has been introduced between the links of a train of irritative motions, and has dissevered, or much enfeebled them. Dr. Smyth, in his Essay on Swinging in Pulmonary Consumption, has observed, that swinging makes the pulse slower. Dr. Ewart of Bath confirmed this observation both on himself and on Col. Cathcart, who was then hectic, and that even on shipboard, where some degree of vertigo might be supposed previously to exist. Dr. Currie of Liverpool not only confirmed this observation frequently on himself, when he was also phthisical, but found that equitation had a similar effect on him, uniformly retarding his pulse. This curious circumstance cannot arise from the general effect of exercise, or fatigue, as in those cases the pulse becomes weaker and quicker; it must therefore be ascribed to a degree of vertigo, which attends all those modes of motion, which we are not perpetually accustomed to. Dr. Currie has further observed, that "in cases of great debility the voluntary muscular exertion requisite in a swing produces weariness, that is, increases debility; and that in such instances he had frequently noticed, that the diminution of the frequency of the pulse did not take place, but the contrary." These circumstances may thus be accounted for. The links of association, which are effected in the vertigo occasioned by unusual motion, are the irritative motions of the sense of vision, those of the stomach, and those of the heart and arteries. When the irritative ideas of vision are exerted with greater energy at the beginning of vertigo, a degree of sensation is excited, which is of the pleasurable kind, as above mentioned; whence the associated trains of irritative motions of the stomach, and heart, and arteries, act at first with greater energy, both by direct sympathy; and by the additional sensorial power of sensation. Whence the pulse of a consumptive patient becomes stronger and consequently slower. But if this vertigo becomes much greater in degree or duration, the first link of this train of associated irritative motions expends too much of the sensorial power, which was usually employed on the whole train; and the motions of the stomach become in consequence exerted with less energy. This appears, because in this degree of vertigo sickness supervenes, as in sea-sickness, which has been shewn to be owing to less energetic action of the stomach. And the motions of the heart and arteries then become weaker, and in consequence more frequent, by their direct sympathy with the lessened actions of the stomach. See Supplement, I. 12. and Class II. 1. 6. 7. The general weakness from fatigue is owing to a similar cause, that is, to the too great expenditure of sensorial power in the increased actions of one part of the system, and the consequent deficiency of it in other parts, or in the whole. The abatement of the heat of the skin in hectic fever by swinging, is not only owing to the increased ventilation of cool air, but to the reverse sympathy of the motions of the cutaneous capillaries with those of the heart and arteries; which occurs in all fevers with arterial debility, and a hot or dry skin. Hence during moderate swinging the action of the heart and arteries becomes stronger and slower, and the action of the capillaries, which was before too great, as appeared by the heat of the skin, now is lessened by their reverse sympathy with that of the heart and arteries. See Supplement, I. 8. 11. _Vertigo visualis._ Visual vertigo. The vertigo rotatoria described above, was induced by the rotation or undulation of external objects, and was attended with increased action of the primary link of the associated motions belonging to vision, and with consequent pleasure. The vertigo visualis is owing to less perfect vision, and is not accompanied with pleasurable sensation. This frequently occurs in strokes of the palsy, and is then succeeded by vomiting; it sometimes precedes epileptic fits, and often attends those, whose sight begins to be impaired by age. In this vertigo the irritative ideas of the apparent motions of objects are less distinct, and on that account are not succeeded by their usual irritative associations of motion; but excite our attention. Whence the objects appear to librate or circulate according to the motions of our heads, which is called dizziness; and we lose the means of balancing ourselves, or preserving our perpendicularity, by vision. So that in this vertigo the motions of the associated organs are decreased by direct sympathy with their primary link of irritation; as in the preceding case of sea-sickness they are decreased by reverse sympathy. When vertigo affects people about fifty years of age, their sight has generally been suddenly impaired; and from their less accurate vision they do not soon enough perceive the apparent motions of objects; like a person in a room, the walls of which are stained with the uniform figures of lozenges, explained in Sect. XX. 1. This is generally ascribed to indigestion; but it ceases spontaneously, as the patient acquires the habit of balancing himself by less distinct objects. A gentleman about 50 was seized with an uncommon degree of vertigo, so as to fall on the ground, and not to be able to turn his head, as he sat up either in his chair or in his bed, and this continued eight or ten weeks. As he had many decayed teeth in his mouth, and the vertigo was preceded and sometimes accompanied by pains on one side of his head, the disease of a tooth was suspected to be the cause. And as his timidity was too great to admit the extraction of those which were decayed; after the trial of cupping repeatedly, fomentations on his head, repeated blisters, with valerian, Peruvian bark, musk, opium, and variety of other medicines; mercurials were used, both externally and internally, with design to inflame the membranes of the teeth, and by that means to prevent the torpor of the action of the membranes about the temple, and parietal bone; which are catenated with the membranes of the teeth by irritative association, but not by sensitive association. The event was, that as soon as the gums became sore with a slight ptyalism, the pains about the head and vertigo gradually diminished, and during the soreness of his gums entirely ceased; but I believe recurred afterwards, though in less degree. The idea of inflaming the membranes of the teeth to produce increased sensation in them, and thus to prevent their irritative connection with those of the cranium, was taken from the treatment of trismus, or locked jaw, by endeavouring to inflame the injured tendon; which is said to prevent or to remove the spasm of the muscles of the jaw. See Class III. 1. 1. 13. and 15. M. M. Emetics. Blisters. Issues about the head. Extraction of decayed teeth. Slight salivation. Sorbentia. Incitantia. 12. _Vertigo ebriosa._ Vertigo from intoxication is owing to the association of the irritative ideas of vision with the irritative motions of the stomach. Whence when these latter become much increased by the immoderate stimulus of wine, the irritative motions of the retina are produced with less energy by reverse sympathy, and become at the same time succeeded by sensation in consequence of their decreased action. See Sect. XXI. 3. and XXXV. 1. 2. So conversely when the irritative motions of vision are increased by turning round, or by our unaccustomed agitation at sea, those of the stomach become inverted by reverse sympathy, and are attended in consequence with disagreeable sensation. Which decreased action of the stomach is in consequence of the increased expenditure of the sensorial power on the irritative ideas of vision, as explained in Vertigo rotatoria. Whence though a certain quantity of vinous spirit stimulates the whole system into increased action, and perhaps even increases the secretion of sensorial power in the brain; yet as soon as any degree of vertigo is produced, it is a proof, that by the too great expenditure of sensorial power by the stomach, and its nearest associated motions, the more distant ones, as those of vision, become imperfectly exerted. From hence may be deduced the necessity of exhibiting wine in fevers with weak pulse in only appropriated quantity; because if the least intoxication be induced, some part of the system must act more feebly from the unnecessary expenditure of sensorial power. 13. _Vertigo febriculosa._ Vertigo in fevers either proceeds from the general deficiency of sensorial power belonging to the irritative associations, or to a greater expenditure of it on some links of the trains and tribes of associated irritative motions. There is however a slighter vertigo attending all people, who have been long confined in bed, on their first rising; owing to their having been so long unused to the apparent motions of objects in their erect posture, or as they pass by them, that they have lost in part the habit of balancing themselves by them. 14. _Vertigo cerebrosa._ Vertigo from injuries of the brain, either from external violence, or which attend paralytic attacks, are owing to the general deficiency of sensorial power. In these distressful situations the vital motions, or those immediately necessary to life, claim their share of sensorial power in the first place, otherwise the patient must die; and those motions, which are less necessary, feel a deficiency of it, as these of the organs of sense and muscles; which constitute vertigo; and lastly the voluntary motions, which are still less immediately necessary to life, are frequently partially destroyed, as in palsy; or totally, as in apoplexy. 15. _Murmur aurium vertiginosum._ The vertiginous murmur in the ears, or noise in the head, is compared to the undulations of the sound of bells, or to the humming of bees. It frequently attends people about 60 years of age; and like the visual vertigo described above is owing to our hearing less perfectly from the gradual inirritability of the organ on the approach of age; and the disagreeable sensation of noise attending it is owing to the less energetic action of these irritative motions; which not being sufficiently distinct to excite their usual associations become succeeded by our attention, like the indistinct view of the apparent motions of objects mentioned in vertigo visualis. This may be better understood from considering the use, which blind men make of these irritative sounds, which they have taught themselves to attend to, but which escape the notice of others. The late blind Justice Fielding walked for the first time into my room, when he once visited me, and after speaking a few words said, "this room is about 22 feet long, 18 wide, and 12 high;" all which he guessed by the ear with great accuracy. Now if these irritative sounds from the partial loss of hearing do not correspond with the size or usual echoes of the places, where we are; their catenation with other irritative ideas, as those of vision, becomes dissevered or disturbed; and we attend to them in consequence, which I think unravels this intricate circumstance of noises being always heard in the head, when the sense of hearing begins to be impaired, from whatever cause it occurs. This ringing in the ears also attends the vertigo from intoxication; for the irritative ideas of sound are then more weakly excited in consequence of the deficiency of the sensorial power of association. As is known by this also being attended with disagreeable sensation, and by its accompanying other diseases of debility, as strokes on the head, fainting fits, and paralytic seizures. For in this vertigo from intoxication so much sensorial power in general is expended on the increased actions of the stomach, and its nearest connections, as the capillaries of the skin; that there is a deficiency for the purposes of the other irritative associations of motions usually connected with it. This auditory vertigo attends both the rotatory and the visual vertigo above mentioned; in the former it is introduced by reverse sympathy, that is, by the diminution of sensorial power; too great a quantity of it being expended on the increased irritative motions of vision; in the latter it is produced either by the same causes which produce the visual vertigo, or by direct sympathy with it. See Sect. XX. 7. M. M. Stimulate the internal ear by ether, or with essential oil diluted with expressed oil, or with a solution of opium in wine, or in water. Or with salt and water. 16. _Tactus, gustus, olfactius vertiginosi._ Vertiginous touch, taste, and smell. In the vertigo of intoxication, when the patient lies down in bed, it sometimes happens even in the dark, that the bed seems to librate under him, and he is afraid of falling out of it. The same occurs to people, who are sea-sick, even when they lie down in the dark. In these the irritative motions of the nerves of touch, or irritative tangible ideas, are performed with less energy, in one case by reverse sympathy with the stomach, in the other by reverse sympathy with the nerves of vision, and in consequence become attended with sensation, and produce the fear of falling by other associations. A vertigo of the sense of touch may be produced, if any one turns round for a time with his eyes shut, and suddenly stops without opening them; for he will for a time seem to be still going forwards; which is difficult to explain. See the notes at the end of the first and second volume belonging to Sect. XX. 6. In the beginning of some fevers, along with incessant vomiting, the patients complain of disagreeable tastes in their mouth, and disagreeable odours; which are to be ascribed to the general debility of the great trains and tribes of associated irritative motions, and to be explained from their direct sympathy with the decreased action of a sick stomach; or from the less secretion of sensorial power in the brain. These organs of sense are constantly stimulated into action by the saliva or by the air; hence, like the sense of hunger, when they are torpid from want of stimulus, or from want of sensorial power, pain or disagreeable sensation ensues, as of hunger, or faintness, or sickness in one case; and the ideas of bad tastes or odours in the other. This accords with the laws of causation, Sect. IV. 5. 17. _Pulsus mollis in vomitione._ The softness of the pulse in the act of vomiting is caused by direct association between the heart and the stomach; as explained in Sect. XXV. 17. A great slowness of the pulsation of the heart sometimes attends sickness, and even with intermissions of it, as in the exhibition of too great a dose of digitalis. 18. _Pulsus intermittens a ventriculo._ When the pulse first begins to intermit, it is common for the patient to bring up a little air from his stomach; which if he accomplishes before the intermission occurs, always prevents it; whence that this debility of the heart is owing to the direct association of its motions with those of the stomach is well evinced. See Sect. XXV. 17. I this morning saw Mr. ----, who has long had at times an unequal pulse, with indigestion and flatulency, and occasional asthma; he was seized two days ago with diarrhoea, and this morning with sickness, and his pulse was every way unequal. After an emetic his pulse still continued very intermittent and unequal. He then took some breakfast of toast and butter, and tea, and to my great surprise his pulse became immediately perfectly regular, about 100 in a minute, and not weak, by this stimulus on his stomach. A person, who for many years had had a frequent intermission of his pulse, and occasional palpitation of his heart, was relieved from them both for a time by taking about four drops of a saturated solution of arsenic three or four times a day for three or four days. As this intermission of the pulse is occasioned by the direct association of the motions of the heart with those of the stomach, the indication of cure must be to strengthen the action of the stomach by the bark. Spice. Moderate quantities of wine. A blister. Half a grain of opium twice a day. Solution of arsenic? 19. _Febris inirritativa._ Inirritative fever described in Class I. 2. 1. 1. belongs to this place, as it consists of disordered trains and tribes of associated irritative motions, with lessened actions of the associated organs. In this fever the pulsations of the heart and arteries are weakened or lessened, not only in the cold paroxysm, as in the irritative fever, but also in the hot paroxysm. The capillary arteries or glands have their actions nevertheless increased after the first cold fit, as appears by the greater production of heat, and the glow of arterial blood, in the cutaneous vessels; and lastly, the action of the stomach is much impaired or destroyed, as appears by the total want of appetite to solid food. Whence it would seem, that the torpid motions of the stomach, whatever may occasion them, are a very frequent cause of continued fever with weak pulse; and that these torpid motions of the stomach do not sufficiently excite the sensorial power of association, which contributes in health to actuate the heart and arteries along with the irritation produced by the stimulus of the blood; and hence the actions of these organs are weaker. And lastly, that the accumulation of the sensorial power of association, which ought to be expended on the motions of the heart and arteries, becomes now exerted on the cutaneous and pulmonary capillaries. See Supplement I. 8. and Sect. XXXV. 1. 1. and XXXIII. 2. 10. I have dwelt longer on the vertiginous diseases in this genus, both because of their great intricacy, and because they seem to open a road to the knowledge of fever, which consists of associated trains and tribes of irritative or sensitive motions, which are sometimes mixed with the vertiginous ones, and sometimes separate from them. * * * * * ORDO II. _Decreased Associate Motions._ GENUS II. _Catenated with Sensitive Motions._ In this genus the sensorial power of association is exerted with less energy, and thence the actions produced by it are less than natural; and pain is produced in consequence, according to the fifth law of animal causation, Sect. IV. This pain is generally attended with coldness of the affected part, and is seldom succeeded by inflammation of it. This decreased action of the secondary link of the associated motions, belonging to this genus, is owing to the previous exhaustion of sensorial power either in the increased actions of the primary link of the associated motions, or by the pain which attends them; both which are frequently the consequence of the stimulus of something external to the affected fibres. As pain is produced either by excess or defect of the natural exertions of the fibres, it is not, considered separately, a criterion of the presence of either. In the associations belonging to this genus the sensation of pain or pleasure produces or attends the primary link of the associated motions, and very often gives name to the disease. When great pain exists without causing any fibrous motions, I conjecture that it contributes to exhaust or expend the general quantity of sensorial power; because people are fatigued by enduring pain, till at length they sleep. Which is contrary to what I had perhaps erroneously supposed in Sect. XXXV. 2. 3. If it causes fibrous motions, it then takes the name of sensation, according to the definition of sensation in Sect. II. 2. 9.; and increased fibrous action or inflammation is the consequence. This circumstance of the general exhaustion of sensorial power by the existence of pain will assist in explaining many of the diseases of this genus. Many of the canals of the body, as the urethra, the bile-duct, the throat, have the motions of their two extremities associated by having been accustomed to feel pleasurable or painful sensations at the same time or in succession. This is termed sensitive association, though those painful or pleasurable sensations do not cause the motions, but only attend them; and are thus perhaps, strictly speaking, only catenated with them. SPECIES. 1. _Torpor genæ a dolore dentis._ In tooth-ach there is generally a coldness of the cheek, which is sensible to the hand, and is attended in some degree with the pain of cold. The cheek and tooth have frequently been engaged in pleasurable action at the same time during the masticating of our food; whence they have acquired sensitive associations. The torpor of the cheek may have for its cause the too great expenditure of sensorial power by the painful sensation of the membranes of the diseased tooth; whence the membranes of the cheek associated with those of the alveolar process are deprived of their natural share of it, and become torpid; thus they produce less secretions, and less heat, and the pain of cold is the consequence. This torpor of the vessels of the cheek cannot be produced by the activity of the sensorial power of sensation; for then they would act more violently than natural, or become inflamed. And though the pain by exhausting so much sensorial power may be a remote cause, it is the defeat of the power of association, which is the immediate cause of the torpor of the cheek. After some hours this pain occasioned by the torpor of the vessels of the cheek either gradually ceases along with the pain of the diseased tooth; or, by the accumulation of sensorial power during their state of torpor, the capillaries of the cheek act with greater violence, and produce more secretions, and heat, and consequent tumour, and inflammation. In this state the pain of the diseased tooth ceases; as the sensorial power of sensation is now expended on the inflamed vessels of the cheek. It is probable that most other internal membranous inflammations begin in a similar manner; whence there may seem to be a double kind of sensitive association; first, with decreased action of the associated organ, and then with increased action of it; but the latter is in this case simply the consequence of the former; that is, the tumor or inflammation of the cheek is in consequence of its previous quiescence or torpor. 2. _Stranguria a dolore vesicæ._ The strangury, which has its origin from pain at the neck of the bladder, consists of a pain in the external extremity of the urethra or of the glans penis of men, and probably in the external termination of the urethra or of the clitoris of women; and is owing to the sympathy of these with some distant parts, generally with the other end of the urethra; an endeavour and difficulty of making water attends this pain. Its remote cause is from the internal or external use of cantharides, which stimulate the neck of the bladder; or from a stone, which whenever it is pushed into the neck of the bladder, gives this pain of strangury, but not at other times; and hence it is felt most severely in this case after having made water. The sensations or sensitive motions of the glans penis, and of the sphincter of the bladder, have been accustomed to exist together during the discharge of the urine; and hence the two ends of the urethra sympathize by association. When there is a stone at the neck of the bladder, which is not so large or rough as to inflame the part, the sphincter of the bladder becomes stimulated into pain; but as the glans penis is for the purposes of copulation more sensitive than the sphincter of the bladder, as soon as it becomes affected with pain by the association above mentioned, the sensation at the neck of the bladder ceases; and then the pain of the glans penis would seem to be associated with the irritative motions only of the sphincter of the bladder, and not with the sensitive ones of it. But a circumstance similar to this occurs in epileptic fits, which at first are induced by disagreeable sensation, and afterwards seem to occur without previous pain, from the suddenness in which they follow and relieve the pain, which occasioned them. From this analogy I imagine the pain of the glans penis is associated with the pain of the sphincter of the bladder; but that _as soon as the greater pain in a more sensible part is produced; the lesser one, which occasioned it, ceases_; and that this is one of the laws of sensitive association. See Sect. XXXV. 2. 1. A young man had by an accident swallowed a large spoonful or more of tincture of cantharides; as soon as he began to feel the pain of strangury, he was advised to drink large quantities of warmish water; to which, as soon as it could be got, some gum arabic was added. In an hour or two he drank by intervals of a few minutes about two gallons of water, and discharged his urine every four or five minutes. A little blood was voided towards the end, but he suffered no ill consequence. M. M. Warm water internally. Clysters of warm water. Fomentation. Opium. Solution of fixed alkali supersaturated with carbonic acid. A bougie may be used to push back a stone into the bladder. See Class I. 1. 3. 10. 3. _Stranguria convulsiva._ The convulsive strangury, like that before described, is probably occasioned by the torpor or defective action of the painful part in consequence of the too great expenditure of sensorial power on the primary link of the associated motions, as no heat or inflammation attends this violent pain. This kind of strangury recurs by stated periods, and sometimes arises to so great a degree, that convulsion or temporary madness terminates each period of it. It affects women oftener than men, is attended with cold extremities without fever, and is distinguished from the stone of the bladder by the regularity of its periods, and by the pain being not increased after making water. On introducing the catheter sometimes part of the urine will come away and not the whole, which is difficult to explain; but may arise from the weakness of the muscular fibres of the bladder; which are not liable suddenly to contract themselves so far as to exclude the whole of the urine. In some old people, who have experienced a long retention of urine, the bladder never regains the power of completely emptying itself; and many who are beginning to be weak from age can make water a second time, a few minutes after they supposed they had emptied the bladder. I have believed this pain to originate from sympathy with some distant part, as from ascarides in the rectum, or from piles in women; or from caruncles in the urethra about the caput gallinaginis in men; and that the pain has been in the glans or clitoris by reverse sympathy of these more sensible parts with those above mentioned. M. M. Venesection. Opium in large quantities. Warm bath. Balsams. Bark. Tincture of cantharides. Bougie, and the treatment for hæmorrhoids. Leeches applied to the sphincter ani. Aerated alcaline water. Soap and sal soda. Opium in clysters given an hour before the expected return. Smoke of tobacco in clysters. Arsenic? 4. _Dolor termini intestinalis ductûs choledochi._ Pain at the intestinal end of the gall-duct. When a gall-stone is protruded from the gall-bladder a little way into the end of the gall-duct, the pain is felt at the other end of the gall-duct, which terminates in the duodenum. For the actions of the two terminations of this canal are associated together from the same streams of bile passing through them in succession, exactly as the two terminations of the urethra have their actions associated, as described in Species 2 and 3 of this genus. But as the intestinal termination of the bile-duct is made more sensible for the purpose of bringing down more bile, when it is stimulated by new supplies of food from the stomach, it falls into violent pain from association; and then the pain on the region of the gall-bladder ceases, exactly as above explained in the account of the pain of the glans penis from a stone in the sphincter of the bladder. The common bile-duct opens into the intestine exactly at what is called the pit of the stomach; and hence it has sometimes happened, that this pain from association with the sensation of a gall-stone at the other end of the bile-duct has been mistaken for a pain of the stomach. For the method of cure see Class I. 1. 3. 8. to which should be added the use of strong electric shocks passed through the bile-duct from the pit of the stomach to the back, and from one side to the other. A case of the good effect of electricity in the jaundice is related in Sect. XXX. 2. And another case, where it promoted the passage of a painful gall-stone, is described by Dr. Hall, experienced on himself. Trans. of the College at Philadelphia, Vol. I. p. 192. Half a pint of warm water two or three times a day is much recommended to dilute the inspissated bile. 5. _Dolor pharyngis ab acido gastrico._ The two ends of the throat sympathize by sensitive association in the same manner as the other canals above mentioned, namely, the urethra and the bile-duct; hence when too great acidity of undigested aliment, or the carbonic acid air, which escapes in fermentation, stimulates the cardia ventriculi, or lower end of the gula, into pain; the pharinx, or upper end of it, is affected with greater pain, or a disagreeable sensation of heat. 6. _Pruritus narium a vermibus._ The itching of the nose from worms in the intestines is another curious instance of the sensitive associations of the motions of membranes; especially of those which constitute the canals of the body. Previous to the deglutition of agreeable food, as milk in our earliest infancy, an agreeable odour affects the membrane, which lines the nostrils; and hence an association seems to take place between the agreeable sensations produced by food in the stomach and bowels, and the agreeable sensations of the nostrils. The existence of ascarides in the rectum I believe produces this itching of the nostrils more than the worms in other parts of the intestines; as we have already seen, that the terminations of canals sympathize more than their other parts, as in the urethra and gall-ducts. See Class I. 1. 5. 9. IV. 1. 2. 9. 7. _Cephalæa._ Head-ach. In cold fits of the ague, the head-ach arises from consent with some torpid viscus, like the pain of the loins. After drunkenness the head-ach is very common, owing to direct sympathy of the membranes of the head with those of the stomach; which is become torpid after the too violent stimulus of the preceding intoxication; and is hence removeable by spirit of wine, or opium, exhibited in smaller quantities. In some constitutions these head-achs are induced, when the feet are exposed to much external cold; in this case the feet should be covered with oiled silk, which prevents the evaporation of the perspirable matter, and thence diminishes one cause of external cold. M. M. Valerian in powder two drams three or four times a day is recommended. The bark. Chalybeates. A grain of opium twice a day for a long time. From five to ten drops of the saturated solution of arsenic two or three times a day. See Class I. 2. 4. 11. A lady once assured me, that when her head-ach was coming on, she drank three pints (pounds) of hot water, as hastily as she could; which prevented the progress of the disease. A solution of arsenic is recommended by Dr. Fowler of York. Very strong errhines are said sometimes to cure head-achs taken at the times the pain recurs, till a few drops of blood issue from the nostrils. As one grain of turpeth mineral (vitriolic calx of mercury) mixed with ten grains of fine sugar. Euphorbium or cayan pepper mixed with sugar, and used with caution as an errhine. See the M. M. of the next Species. 8. _Hemicrania._ Pain on one side of the head. This disease is attended with cold skin, and hence whatever may be the remote cause, the immediate one seems to be want of stimulus, either of heat or distention, or of some other unknown stimulus in the painful part; or in those, with which it is associated. The membranes in their natural state are only irritable by distention; in their diseased state, they are sensible like muscular fibres. Hence a diseased tooth may render the neighbouring membranes sensible, and is frequently the cause of this disease. Sometimes the stomach is torpid along with the pained membrane of the head; and then sickness and inappetency attends either as a cause or consequence. The natural cure of hemicrania is the accumulation of sensorial power during the rest or sickness of the patient. Mrs. ---- is frequently liable to hemicrania with sickness, which is probably owing to a diseased tooth; the paroxysm occurs irregularly, but always after some previous fatigue, or other cause of debility. She lies in bed, sick, and without taking any solid food, and very little of fluids, and those of the aqueous kind, and, after about 48 or 50 hours, rises free from complaint. Similar to this is the recovery from cold paroxysms of fever, from the torpor occasioned by fear, and from syncope; which are all owing to the accumulation of sensorial power during the inactivity of the system. Hence it appears, that, though when the sensorial power of volition is much exhausted by fatigue, it can be restored by eight or ten hours of sleep; yet, when the sensorial power of irritation is exhausted by fatigue, that it requires two whole solar or lunar days of rest, before it can be restored. The late Dr. Monro asserted in his lectures, that he cured the hemicrania, or megrim, by a strong vomit, and a brisk purge immediately after it. This method succeeds best if opium and the bark are given in due quantity after the operation of the cathartic; and with still more certainty, if bleeding in small quantity is premised, where the pulse will admit of it. See Sect. XXXV. 2. 1. The pain generally affects one eye, and spreads a little way on that side of the nose, and may sometimes be relieved by pressing or cutting the nerve, where it passes into the bone of the orbit above the eye. When it affects a small defined part on the parietal bone on one side, it is generally termed Clavus hystericus, and is always I believe owing to a diseased dens molaris. The tendons of the muscles, which serve the office of mastication, have been extended into pain at the same time, that the membranous coverings of the roots of the teeth have been compressed into pain, during the biting or mastication of hard bodies. Hence when the membranes, which cover the roots of the teeth, become affected with pain by a beginning decay, or perhaps by the torpor or coldness of the dying part of the tooth, the tendons and membranous fascia of the muscles about the same side of the head become affected with violent pain by their sensitive associations: and as soon as this associated pain takes place, the pain of the tooth entirely ceases, as explained in the second species of this genus. A remarkable circumstance attends this kind of hemicrania, viz. that it recurs by periods like those of intermittent fevers, as explained in the Section on Catenation of Motions; these periods sometimes correspond with alternate lunar or solar days like tertian agues, and that even when a decaying tooth is evidently the cause; which has been evinced by the cure of the disease by extracting the tooth. At other times they observe the monthly lunations, and seem to be induced by the debility, which attends menstruation. The dens sapientiæ, or last tooth of the upper jaw, frequently decays first, and gives hemicrania over the eye on the same side. The first or second grinder in the under-jaw is liable to give violent pain about the middle of the parietal bone, or side of the head, on the same side, which is generally called the Clavus hystericus, of which an instructive case is related in Sect. XXXV. 2. 1. M. M. Detect and extract the diseased tooth. Cut the affected nerve, or stimulate the diseased membrane by acu-puncture. Venesection to six ounces by the lancet or by leeches. A strong emetic and a subsequent cathartic; and then an opiate and the bark. Pass small electric shocks through the pained membrane, and through the teeth on the same side. Apply vitriolic ether externally, and a grain of opium with camphor internally, to the cheek on the affected side, where a diseased tooth may be suspected. Foment the head with warm vinegar. Drink two large spoonfuls of vinegar. Stimulate the gums of the suspected teeth by oil of cloves, by opium. See Class I. 1. 4. 4. Snuff volatile spirit of vinegar up the nostrils. Lastly, in permanent head-achs, as in permanent vertigo, I have seen good effect by the use of mercurial ointment rubbed on the shaved head or about the throat, till a mild salivation commences, which by inflaming the membranes of the teeth may prevent their irritative sympathy with those of the cranium. Thus by inflaming the tendon, which is the cause of locked jaw, and probably by inflaming the wound, which is the cause of hydrophobia, those diseases may be cured, by disuniting the irritative sympathy between those parts, which may not possess any sensitive sympathy. This idea is well worth our attention. _Otalgia._ Ear-ach is another disease occasioned by the sympathy of the membranes of the ear with those which invest or surround a decaying tooth, as I have had frequent reason to believe; and is frequently relieved by filling the ear with tincture of opium. See Class I. 2. 4. 9. _Dolor humeri in hepatitide._ In the efforts of excluding the fæces and urine the muscles of the shoulders are exerted to compress the air in the lungs, that the diaphragm may be pressed down. Hence the distention of the tendons or fibres of these muscles is associated with the distention of the tendons or fibres of the diaphragm; and when the latter are pained by the enlargement or heat of the inflamed liver, the former sympathize with them. Sometimes but one shoulder is affected, sometimes both; it is probable that many other pains, which are termed rheumatic, have a similar origin, viz. from sensitive associations. As no inflammation is produced in consequence of this pain of the shoulder, it seems to be owing to inaction of the membranous part from defect of the sensorial power of association, of which the primary link is the inflamed membrane of the liver; which now expends so much of the sensorial power in general by its increased action, that the membranes about the shoulder, which are links of association with it, become deprived of their usual share, and consequently fall into torpor. 10. _Torpor pedum in eruptione variolarum._ At the commencement of the eruption of the small-pox, when the face and breast of children are very hot, their extremities are frequently cold. This I ascribe to sensitive association between the different parts of the skin; whence when a part acts too violently, the other part is liable to act too weakly; and the skin of the face being affected first in the eruption of the small-pox, the skin of the feet becomes cold in consequence by reverse sympathy. M. M. Cover the feet with flannel, and expose the face and bosom to cool air, which in a very short time both warms the feet and cools the face; and hence what is erroneously called a rash, but which is probably a too hasty eruption of the small-pox, disappears; and afterwards fewer and more distinct eruptions of the small-pox supervene. 11. _Testium dolor nephriticus._ The pain and retraction of the testicle on the same side, when there is a stone in the ureter, is to be ascribed to sensitive association; whether the connecting cause be a branch of the same nerve, or from membranes, which have been frequently affected at the same time. 12. _Dolor digiti minimi sympatheticus._ When any one accidentally strikes his elbow against any hard body, a tingling pain runs down to the little finger end. This is owing to sensitive association of motions by means of the same branch of a nerve, as in hemicrania from a decaying tooth the pain is owing to the sensitive association of tendons or membranes. 13. _Dolor brachii in hydrope pectoris._ The pain in the left arm which attends some dropsies of the chest, is explained in Sect. XXIX. 5. 2. 10. which resembles the pain of the little finger from a percussion of the nerve at the elbow in the preceding article. A numbness of this kind is produced over the whole leg, when the crural nerve is much compressed by sitting for a time with one leg crossed over the other. Mr. ----, about sixty, had for two years been affected with difficulty of respiration on any exertion, with pain about the sternum, and of his left arm; which last was more considerable than is usual in dropsy of the chest; some months ago the pain of his arm, after walking a mile or two, became excessive, with coldness and numbness; and on the next day the back of the hand, and a part of the arm swelled, and became inflamed, which relieved the pain; and was taken for the gout, and continued several days. He after some months became dropsical both in respect to his chest and limbs, and was six or seven times perfectly relieved by one dram of saturated tincture of digitalis, taken two or three times a day for a few days in a glass of peppermint water. He afterwards breathed oxygen gas undiluted, in the quantity of six or eight gallons a day for three or four weeks without any effect, and sunk at length from general debility. In this instructive case I imagine the pressure or stimulus of one part of the nerve within the chest caused the other part, which serves the arm, to become torpid, and consequently cold by sympathy; and that the inflammation was the consequence of the previous torpor and coldness of the arm, in the same manner as the swelling and inflammation of the cheek in tooth-ach, in the first species of this genus; and that many rheumatic inflammations are thus produced by sympathy with some distant part. 14. _Diarrhoea a dentitione._ The diarrhoea, which frequently attends dentition, is the consequence of indigestion; the aliment acquires chemical changes, and by its acidity acts as a cathartic; and changes the yellow bile into green, which is evacuated along with indigested parts of the coagulum of milk. The indigestion is owing to the torpor of the stomach and intestines caused by their association with the membranes of the gums, which are now stimulated into great exertion with pain; both which contribute to expend the general quantity of sensorial power, which belongs to this membranous association; and thus the stomach and intestines act with less than their natural energy. This is generally esteemed a favourable symptom in difficult dentition, as the pain of the alveolar membranes exhausts the sensorial power without producing convulsions for its relief. See Class I. 1. 4. 5. And the diarrhoea ceases, as the tooth advances. * * * * * ORDO II. _Decreased Associate Motions._ GENUS III. _Catenated with Voluntary Motions._ SPECIES. 1. _Titubatio linguæ._ Impediment of speech is owing to the associations of the motions of the organs of speech being interrupted or dissevered by ill-employed sensation or sensitive motions, as by awe, bashfulness, ambition of shining, or fear of not succeeding, and the person uses voluntary efforts in vain to regain the broken associations, as explained in Sect. XVII. 1. 10. and XVII. 2. 10. The broken association is generally between the first consonant and the succeeding vowel; as in endeavouring to pronounce the word parable, the p is voluntarily repeated again and again, but the remainder of the word does not follow, because the association between it and the next vowel is dissevered. M. M. The art of curing this defect is to cause the stammerer to repeat the word, which he finds difficult to speak, eight or ten times without the initial letter, in a strong voice, or with an aspirate before it, as arable, or harable; and at length to speak it very softly with the initial letter p, parable. This should be practised for weeks or months upon every word, which the stammerer hesitates in pronouncing. To this should be added much commerce with mankind, in order to acquire a carelessness about the opinions of others. 2. _Chorea St. Viti._ In the St. Vitus's dance the patient can at any time lie still in bed, which shews the motions not to be convulsive; and he can at different times voluntarily exert every muscle of his body; which evinces, that they are not paralytic. In this disease the principal muscle in any designed motion obeys the will; but those muscles, whose motions were associated with the principal one, do not act; as their association is dissevered, and thus the arm or leg is drawn outward, or inward, or backward, instead of upward or forward, with various gesticulations exactly resembling the impediment of speech. This disease is frequently left after the itch has been too hastily cured. See Convulsio dolorifica, Class III. 1. 1. 6. A girl about eighteen, after wearing a mercurial girdle to cure the itch, acquired the Chorea St. Viti in so universal a manner, that her speech became affected as well as her limbs; and there was evidently a disunion of the common trains of ideas; as the itch was still among the younger children of the family, she was advised to take her sister as a bedfellow, and thus received the itch again; and the dance of St. Vitus gradually ceased. See Class II. 1. 5. 6. M. M. Give the patient the itch again. Calomel a grain every night, or sublimate a quarter of a grain twice a day for a fortnight. Steel. Bark. Warm-bath. Cold-bath. Opium. Venesection once at the beginning of the disease. Electricity. Perpetual slow and repeated efforts to move each limb in the designed direction, as in the titubatio linguæ above described. 3. _Risus._ Laughter is a perpetual interruption of voluntary exertion by the interposition of pleasurable sensation; which not being checked by any important consequences rises into pain, and requires to be relieved or moderated by the frequent repetition of voluntary exertion. See Sect. XXXIV. 1. 4. and Class III. 1. 1. 4. and IV. 1. 3. 3. 4. _Tremor ex irâ._ The trembling of the limbs from anger. The interruption of the voluntary associations of motions by anger, originates from too great a part of the sensorial power being exerted on the organs of sense; whence the muscles, which ought to support the body upright, are deprived of their due quantity, and tremble from debility. See Class III. 2. 1. 1. 5. _Rubor ex irâ._ Redness from anger. Anger is an excess of aversion, that is of voluntarity not yet employed. It is excited by the pain of offended pride; when it is employed it becomes outrage, cruelty, insanity. The cutaneous capillaries, especially those of the face, are more mobile, that is, more easily excited into increased action, or more easily become torpid, from less variation of sensorial power, than any other parts of the system, which is owing to their being perpetually subject to the vicissitudes of heat and cold, and of extension and corrugation. Hence, when an excess of voluntarity exists without being immediately expended in the actions of the large muscles, the capillary arteries and glands acquire more energetic action, and a flushed skin is produced, with increased secretion of perspirable matter, and consequent heat, owing to the pause or interruption of voluntary action; and thus the actions of these cutaneous vessels become associated between the irascent ideas and irascent muscular actions, which are thus for a time interrupted. 6. _Rubor criminati._ The blushing of accused people, whether guilty or not, appears to be owing to circumstances similar to that of anger; for in these situations there is always a sudden voluntarity, or wish, of clearing their characters arises in the mind of the accused person; which, before an opportunity is given for it to be expended on the large muscles, influences the capillary arteries and glands, as in the preceding article. Whence the increased actions of the capillaries, and the consequent redness and heat, become exerted between the voluntary ideas of self-defence, and the muscular actions necessary for that purpose; which last are thus for a time interrupted or delayed. Even in the blush of modesty or bashfulness there is a self-condemnation for some supposed defect or indecorum, and a sudden voluntarity, or wish, of self-defence; which not being expended in actions of the larger muscles excites the capillaries into action; which in these subjects are more mobile than in others. The blush of young girls on coming into an assembly room, where they expect their dress, and steps, and manner to be examined, as in dancing a minuet, may have another origin; and may be considered as a hot fit of returning confidence, after a previous cold fit of fear. 7. _Tarditas paralytica._ By a stroke of the palsy or apoplexy it frequently happens, that those ideas, which were associated in trains, whose first link was a voluntary idea, have their connection dissevered; and the patient is under the necessity by repeated efforts slowly to renew their associations. In this situation those words, which have the fewest other words associated with them, as the proper names of persons or places, are the most difficult to recollect. And in those efforts of recollection the word opposite to the word required is often produced, as hot for cold, winter for summer, which is owing to our associating our ideas of things by their opposites as well as by their similitudes, and in some instances perhaps more frequently, or more forcibly. Other paralytic patients are liable to give wrong names to external objects, as using the word pigs for sheep, or cows for horses; in this case the association between the idea of the animal and the name of it is dissevered; but the idea of the class or genus of the thing remains; and he takes a name from the first of the species, which presents itself, and sometimes can correct himself, till he finds the true one. 8. _Tarditas senilis._ Slowness of age. The difficulty of associating ideas increases with our age; as may be observed from old people forgetting the business of the last hour, unless they impress it strongly, or by frequent repetition, though they can well recollect the transactions of their youth. I saw an elderly man, who could reason with great clearness and precision and in accurate language on subjects, which he had been accustomed to think upon; and yet did not know, that he had rang the bell by his fire-side in one minute afterwards; nor could then recollect the object he had wanted, when his servant came. Similar to this is the difficulty which old people experience in learning new bodily movements, that is, in associating new muscular actions, as in learning a new trade or manufactury. The trains of movements, which obey volition, are the last which we acquire; and the first, which are disassociated. * * * * * ORDO II. _Decreased Associate Motions._ GENUS IV. _Catenated with External Influences._ As the diseases, which obey solar or lunar periods, commence with torpor or inactivity, such as the cold paroxysms of fevers, the torpor and consequent pain of hemicrania, and the pains which precede the fits of epilepsy and convulsion, it would seem, that these diseases are more generally owing to the diminution than to the excess of solar or lunar gravitation; as the diseases, which originate from the influence of the matter of heat, are much more generally in this country produced by the defect than by the excess of that fluid. The periodic returns of so many diseases coincide with the diurnal, monthly, and annual rounds of time; that any one, who would deny the influence of the sun and moon on the periods of quotidian, tertian, and quartan fevers, must deny their effect on the tides, and on the seasons. It has generally been believed, that solar and lunar effect was exerted on the blood; which was thus rendered more or less stimulant to the system, as described in Sect. XXXII. 6. But as the fluid matter of gravitation permeates and covers all things, like the fluid matter of heat; I am induced to believe, that gravitation acts in its medium state rather as a causa sine quâ non of animal motion, like heat; which may disorder the system chemically or mechanically, when it is diminished; but may nevertheless stimulate it, when increased, into animal exertion. Without heat and motion, which some philosophers still believe to be the same thing, as they so perpetually appear together, the particles of matter would attract and move towards each other, and the whole universe freeze or coalesce into one solid mass. These therefore counteract the gravitation of bodies to one center; and not only prevent the planets from falling into the sun, but become either the efficient causes of vegetable and animal life, or the causes without which life cannot exist; as by their means the component particles of matter are enabled to slide over each other with all the various degrees of fluidity and repulsion. As the attraction of the moon countervails or diminishes the terrene gravitation of bodies on the surface of the earth; a tide rises on that side of the earth, which is turned towards the moon; and follows it, as the earth revolves. Another tide is raised at the same time on the opposite side of the revolving earth; which is owing to the greater centrifugal motion of that side of the earth, which counteracts the gravitation of bodies near its surface. For the earth and moon may be considered as two cannon balls of different sizes held together by a chain, and revolving once a month round a common center of gravity between them, near the earth's surface; at the same time that they perform their annual orbits round the sun. Whence the centrifugal force of that side of the earth, which is farthest from this center of motion, round which the earth and moon monthly revolve, is considerably greater, than the centrifugal force of that side of the earth, which is nearest it; to which should be added, that this centrifugal force not only contributes to diminish the terrene gravitation of bodies on the earth's surface on that side furthest from this center of motion, but also to increase it on that side, which is nearest it. Another circumstance, which tends to raise the tide on the part of the earth's surface, which is most distant from the moon, is, that the attraction of the moon is less on that part of the ocean, than it is on the other parts of the earth. Thus the moon may be supposed to attract the water on the side of the earth nearest it with a power equal to three; and to attract the central parts of the earth with a power equal to two; and the water on the part of the earth most distant from the moon with a power only equal to one. Hence on the side of the earth most distant from the moon, the moon's attraction is less, and the centrifugal force round their common center of motion is greater; both which contribute to raise the tides on that side of the earth. On the side of the earth nearest the moon, the moon's attraction is so much greater as to raise the tides; though the centrifugal force of the surface of the earth round their common center of motion in some degree opposes this effect. On these accounts, when the moon is in the zenith or nadir, the gravitation of bodies on the earth's surface will be greatest at the two opposite quadratures; that is, the greatest gravitation of bodies on the earth's surface towards her center during the lunar day is about six hours and an half after the southing, or after the northing of the moon. Circumstances similar to these, but in a less degree, must occur in respect to the solar influence on terrestrial bodies; that is, there must be a diminution of the gravity of bodies, near the earth's surface at noon, when the sun is over them; and also at midnight from the greater centrifugal force of that side of the earth, which is most distant from the center, round which the earth moves in her annual orbit, than on the side nearest that center. Whence it likewise follows, that the gravitation of bodies towards the earth is greatest about six hours after noon, and after midnight. Now when the sun and moon have their united gravitation on the same side of the earth, as at the new moon; or when the solar attraction coincides with the greater centrifugal motion of that side of the earth, which is furthest distant from the moon, as at the full moon; and when this happens about noon or midnight, the gravitation of terrene bodies towards the earth will be greater about six hours after noon, and after midnight, than at any other part of the lunar period; because the attraction of both these luminaries is then exerted on those sides of the earth over which they hang, which at other times of the month are more or less exerted on other parts of it. Lastly, as heat and motion counteract the gravitation of the particles of bodies to each other, and hence become either the efficient causes of vegetable and animal life, or the causes without which life cannot exist, it seems to follow, that when our gravitation towards the earth's center is greatest, the powers of life should be the least; and hence that those diseases, which begin with torpor, should occur about six hours after the solar or lunar noon, or about six hours after the solar or lunar midnight; and this most frequently about six hours after or before the new or full moon; and especially when these happen at noon or at midnight; or lastly, according to the combination of these powers in diminishing or increasing the earth's attraction to bodies on its surface. The returns or exacerbations of many fevers, both irritative and inflammatory, about six in the evening, and of the periodic cough described in Sect. XXXVI. 3. 9. countenance this theory. Tables might be made out to shew the combined powers of the sun and moon in diminishing the gravitation of bodies on the earth's surface, at every part of their diurnal, monthly, and annual periods; and which might facilitate the elucidation of this subject. But I am well aware of the difficulty of its application to diseases, and hope these conjectures may induce others to publish more numerous observations, and more conclusive reasonings. SPECIES. 1. _Somni periodus._ The periods of sleeping and of waking are shortened or prolonged by so many other circumstances in animal life, besides the minute difference between diurnal and nocturnal solar gravitation, that it can scarcely be ascribed to this influence. At the same time it is curious to observe, that vegetables in respect to their times of sleeping more regularly observe the hour of the day, than the presence or absence of light, or of heat, as may be seen by consulting the calendar of Flora. Botanic Garden, Part II. Canto 2. l. 165. note. Some diseases, which at first sight might be supposed to be influenced by solar periods, seem to be induced by the increasing sensibility of the system to pain during our sleeping hours; as explained in Sect. XVIII. 15. Of these are the fits of asthma, of some epilepsies, and of some hæmoptoes; all which disturb the patient after some hours sleep, and are therefore to be ascribed to the increase of our dormant sensibility. There may likewise be some doubt, whether the commencement of the pain of gout in the foot, as it generally makes its attack after sleep, should be ascribed to the increased sensibility in sleep, or to solar influence? M. M. When asthmatic or epileptic fits or hæmoptoe occur after a certain number of hours of sleep, the patient should be forcibly awakened before the expected time by an alarm clock, and drink a cup of chocolate or lemonade.--Or a grain of opium should be given at going to bed.--In one case to prevent the too great increase of sensibility by shortening the time of sleep; and in the other by increasing the irritative motions, and expending by that means a part of the sensorial power. 2. _Studii inanis periodus._ Class III. 1. 2. 2. The cataleptic spasm which preceded the reverie and somnambulation in the patient, whose case is related in Sect. XIX. 2. occurred at exactly the same hour, which was about eleven in the morning for many weeks; till those periods were disturbed by large doses of opium; and must therefore be referred to some effect of solar gravitation. In the case of Master A. Sect. XXXIV. 3. as the reverie began early in the morning during sleep, there may be a doubt, whether this commenced with torpor of some organ catenated with solar gravitation; or was caused by the existence of a previous torpid part, which only became so painful as to excite the exertions of reverie by the perpetual increase of sensibility during the continuance of sleep, as in some fits of epilepsy, asthma, and hæmoptoe mentioned in the preceding article. 3. _Hemicraniæ periodus._ Periods of hemicrania. Class IV. 2. 2. 8. The torpor and consequent pain of some membranes on one side of the head, as over one eye, is frequently occasioned by a decaying tooth, and is liable to return every day, or on alternate days at solar or lunar periods. In this case large quantities of the bark will frequently cure the disease, and especially if preceded by venesection and a brisk cathartic; but if the offending tooth can be detected, the most certain cure is its extraction. These partial head-achs are also liable to return at the greater lunar periods, as about once a month. Five drops from a two-ounce phial of a saturated solution of arsenic twice a day for a week or two have been said to prevent the returns of this disease. See a Treatise on Arsenic by Dr. Fowler, of York. Strong errhines have also been recommended. 4. _Epilepsiæ dolorificæ periodus._ Class III. 1. 1. 8. The pain which induces after about an hour the violent convulsions or insanity, which constitute the painful epilepsy, generally observe solar diurnal periods for four or five weeks, and are probably governed by solar and lunar times in respect to their greater periods; for I have observed that the daily paroxysms, unless disturbed by large doses of opium, recur at very nearly the same hour, and after a few weeks the patients have recovered to relapse again at the interval of a few months. But more observations are wanted upon this subject, which might be of great advantage in preventing the attacks of this disease; as much less opium given an hour before its expected daily return will prevent the paroxysm, than is necessary to cure it, after it has commenced. 5. _Convulsionis dolorificæ periodus._ Class III. 1. 1. 6. The pains, which produce these convulsions, are generally left after rheumatism, and come on when the patients are become warm in bed, or have been for a short time asleep, and are therefore perhaps rather to be ascribed to the increasing sensibility of the system during sleep, than to solar diurnal periods, as in Species first and second of this Genus. 6. _Tussis periodicæ periodus._ Periodic cough, Class IV. 2. 1. 9. returns at exact solar periods; that described in Sect. XXXVI. 3. 9. recurred about seven in the afternoon for several weeks, till its periods were disturbed by opium, and then it recurred at eleven at night for about a week, and was then totally destroyed by opium given in very large quantities, after having been previously for a few days omitted. 7. _Catameniæ periodus._ Periods of menstruation. The correspondence of the periods of the catamenia with those of the moon was treated of in Sect. XXXII. 6. and can admit of no more doubt, than that the returns of the tides are governed by lunar influence. But the manner in which this is produced, is less evident; it has commonly been ascribed to some effect of the lunar gravitation on the circulating blood, as mentioned in Sect. XXXII. 6. But it is more analogous to other animal phenomena to suppose that the lunar gravitation immediately affects the solids by its influx or stimulus. Which we believe of the fluid element of heat, in which we are equally immersed; and of the electric fluid, which also surrounds and pervades us. See Sect. XXXVI. 2. 3. If the torpor of the uterine veins, which induces the monthly periods of the catamenia, be governed by the increase of terrene gravitation; that is, by the deficiency of the counter-influence of solar and lunar gravitation; why does not it occur most frequently when the terrene gravitation is the greatest, as about six hours after the new moon, and next to that at about six hours after the full moon? This question has its difficulty; first, if the terrene gravitation be greatest about six hours after the new moon, it must become less and less about the same time every lunar day, till the end of the first quarter, when it will be the least; it must then increase daily till the full. After the full the terrene gravitation must again decrease till the end of the third quarter, when it will again be the least, and must increase again till the new moon; that is, the solar and lunar counter-gravitation is greatest, when those luminaries are vertical, at the new moon, and full moon, and least about six hours afterwards. If it was known, whether more menstruations occur about six hours after the moon is in the zenith or nadir; and in the second and fourth quarters of the moon, than in the first and third; some light would be thrown on this subject; which must in that respect wait for future observations. Secondly, if the lunar influence produces a very small degree of quiescence, suppose of the uterine veins, at first; and if that recurs at certain periods, as of lunar days, or about 25 hours, even with less power to produce quiescence than at first; yet the quiescence will daily increase by the acquired habit acting at the same time, as explained in Sect. XII. 3. 3. till at length so great a degree of quiescence will be induced as to cause the inaction of the veins of the uterus, and consequent venous hæmorrhage. See Sect. XXXII. 6. Class I. 2. 1. 11. IV. 1. 4. 4. See the introduction to this Genus. 8. _Hæmorrhoidis periodus._ The periods of the piles depend on the torpor of the veins of the rectum, and are believed to recur nearly at monthly intervals. See Sect. XXVII. 2. and Class I. 2. 1. 6. 9. _Podagræ periodus._ The periods of gout in some patients recur at annual intervals, as in the case related above in Class IV. 1. 2. 15. in which the gouty paroxysm returned for three successive years on nearly the same day of the month. The commencement of the pain of each paroxysm is generally a few hours after midnight, and may thence either be induced by diurnal solar periods, or by the increasing sensibility during sleep, as mentioned in the first species of this genus. 10. _Erysipelatis periodus._ Some kinds of erysipelas which probably originate from the association of the cutaneous vessels with a diseased liver, occur at monthly periods, like the hæmorrhois or piles; and others at annual periods like the gout; as a torpor of some part I suppose always precedes the erysipelatous inflammation, the periods should accord with the increasing influence of terrene gravitation, as described in the introduction to this Genus, and in Species the seventh of it. Other periods of diseases referable to solar and lunar influence are mentioned in Sect XXXVI. and many others will probably be discovered by future observation. 11. _Febrium periodus._ Periods of fevers. The commencement of the cold fits of intermittent fevers, and the daily exacerbations of other fevers, so regularly recur at diurnal solar or lunar periods, that it is impossible to deny their connection with gravitation; as explained in Sect. XXXVI. 3. Not only these exacerbations of fever, and their remissions, obey the diurnal solar and lunar periods; but the preparatory circumstances, which introduce fevers, or which determine their crisises, appear to be governed by the parts of monthly lunar periods, and of solar annual ones. Thus the variolous fever in the natural small-pox commences on the 14th day, and in the inoculated small-pox on the seventh day. The fever and eruption in the distinct kind take up another quarter of a lunation, and the maturation another quarter. The fever, which is termed canine madness, or hydrophobia, is believed to commence near the new or full moon; and, if the cause is not then great enough to bring on the disease, it seems to acquire some strength, or to lie dormant, till another, or perhaps more powerful lunation calls it into action. In the spring, about three or four years ago, a mad dog very much worried one swine confined in a sty, and bit another in the same sty in a less degree; the former became mad, refused his meat, was much convulsed, and died in about four days; this disease commenced about a month after the bite. The other swine began to be ill about a month after the first, and died in the same manner. * * * * * ORDO III. _Retrograde Associate Motions._ GENUS I. _Catenated with Irritative Motions._ Those retrograde associate motions, the first links of which are catenated with irritative motions, belong to this genus. All the retrograde motions are consequent to debility, or inactivity, of the organ; and therefore properly belong to the genera of decreased actions both in this and the former classes. SPECIES. 1. _Diabætes irritata._ When the absorbents of the intestines are stimulated too strongly by spirit of wine, as in the beginning of drunkenness, the urinary absorbents invert their motions. The same happens from worms in the intestines. In other kinds of diabetes may not the remote cause be the too strong action of the cutaneous absorbents, or of the pulmonary ones? May not in such cases oil externally or internally be of service? or warm bathing for an hour at a time? In hysteric inversions of motion is some other part too much stimulated? or pained from the want of stimulus? 2. _Sudor frigidus in asthmate._ The cause of the paroxysms of humoral asthma is not well understood; I suppose it to be owing to a torpidity or inaction of the absorbents belonging to the pulmonary vessels, as happens probably to other viscera at the commencement of intermittent fevers, and to a consequent accumulation of fluids in them; which at length producing great irritation or uneasy sensation causes the violent efforts to produce the absorption of it. The motions of the cutaneous absorbent vessels by their association with those of the pulmonary ones become retrograde, and effuse upon the skin a fluid, which is said to be viscid, and which adheres in drops. A few days ago I saw a young man of delicate constitution in what was called a fit of the asthma; he had about two months before had a peripneumony, and had been ever since subject to difficult respiration on exertion, with occasional palpitation of his heart. He was now seized about eight at night after some exertion of mind in his business with cold extremities, and difficulty of breathing. He gradually became worse, and in about half an hour, the palpitation of his heart and difficult respiration were very alarming; his whole skin was cold and pale, yet he did not shudder as in cold paroxysm of fever; his tongue from the point to the middle became as cold as his other extremities, with cold breath. He seemed to be in the act of dying, except that his pulse continued equal in time, though very quick. He lost three ounces of blood, and took ten drops of laudanum with musk and salt of hartshorn, and recovered in an hour or two without any cold sweat. There being no cold sweat seems to indicate, that there was no accumulation of serous fluid in the lungs; and that their inactivity, and the coldness of the breath, was owing to the sympathy of the air-cells with some distant part. There was no shuddering produced, because the lungs are not sensible to heat and cold; as any one may observe by going from a warm room into a frosty air, and the contrary. So the steam of hot tea, which scalds the mouth, does not affect the lungs with the sensation of heat. I was induced to believe, that the whole cold fit might be owing to suppuration in some part of the chest; as the general difficulty of breathing seemed to be increased after a few days with pulse of 120, and other signs of empyema. Does the cold sweat, and the occurrence of the fits of asthma after sleep, distinguish the humoral asthma from the cold paroxysm of intermittents, or which attends suppuration, or which precedes inflammation?--I heard a few weeks afterwards, that he spit up much matter at the time he died. 3. _Diabætes a timore._ The motions of the absorbent vessels of the neck of the bladder become inverted by their consent with those of the skin; which are become torpid by their reverse sympathy with the painful ideas of fear, as in Sect. XVI. 8. 1. whence there is a great discharge of pale urine, as in hysteric diseases. The same happens from anxiety, where the painful suspense is continued, even when the degree of fear is small; as in young men about to be examined for a degree at the universities the frequency of making water is very observable. When this anxiety is attended with a sleepless night, the quantity of pale urine is amazingly great in some people, and the micturition very frequent. M. M. Opium. Joy. Consolations of friendship. 4. _Diarrhoea a timore._ The absorbent vessels of the intestines invert their motions by direct consent with the skin; hence many liquid stools as well as much pale urine are liable to accompany continued fear, along with coldness of the skin. The immediate cause of this is the decreased sensorial power of association, which intervenes between the actions of the absorbents of the cold skin, and those of the intestinal absorbents; the motions of the latter become on that account weakened and at length retrograde. The remote cause is the torpor of the vessels of the skin catenated with the pain of fear, as explained in Sect. XVI. 8. 1. The capillaries of the skin consent more generally by direct sympathy with those of the lower intestines, and of the bladder; but by reverse sympathy more generally with those of the stomach and upper intestines. As appears in fevers, where the hot skin accompanies indigestion of the stomach; and in diarrhoeas attended with cold extremities. The remote cause is the torpor of the skin owing to its reverse sympathy with the painful sensual motions, or ideas, of fear; which are now actuated with great energy, so as to deprive the second link of associated motions of their due share of sensorial power. It is also probable, that the pain of fear itself may contribute to exhaust the sensorial power, even when it produces no muscular action. See Class IV. 2. 2. 5. _Pallor et tremor a timore._ A retrograde action of the capillaries of the skin producing paleness, and a torpor of the muscular fibres of the limbs occasioning trembling, are caused by their reverse associations with the ideas or imaginations of fear; which are now actuated with violent energy, and accompanied with great pain. The cause of these associations are explained in Sect XVI. 8. 1. These torpid actions of the capillaries and muscles of the limbs are not caused immediately by the painful sensation of fear; as in that case they would have been increased and not decreased actions, as occurs in anger; where the painful volition increases the actions of the capillaries, exciting a blush and heat of the skin. Whence we may gain some knowledge of what is meant by depressing and exciting passions; the former confiding of ideas attended with pain, which pain occasions no muscular actions, like the pain of cold head-ach; the latter being attended with volitions, and consequent muscular exertions. That is, the pain of fear, and the pain of anger, are produced by the exertion of certain ideas, or motions of certain nerves of sense; in the former case, the painful sensation of fear produces no muscular actions, yet it exhausts or employs so much sensorial power, that the whole system acts more feebly, or becomes retrograde; but some parts of it more so than others, according to their early associations described in Sect. XVI. 8. 1. hence the tremor of the limbs, palpitation of heart, and even syncope. In anger the painful volition produces violent muscular actions; but if previous to these any deliberation occurs, a flushed countenance sometimes, and a red skin, are produced by this superabundance of volition exerted on the arterial system; but at other times the skin becomes pale, and the legs tremble, from the exhaustion or expenditure of the sensorial power by the painful volitions of anger on the organs of sense, as by the painful sensations of fear above mentioned. Where the passion of fear exists in a great degree, it exhausts or expends so much sensorial power, either simply by the pain which attends it, or by the violent and perpetual excitement of the terrific imaginations or ideas, that not only a cold and pale skin, but a retrograde motion of the cutaneous absorbents occurs, and a cold sweat appears upon the whole surface of the body, which probably sometimes increases pulmonary absorption; as in Class II. 1. 6. 4. and as in the cold sweats, which attend the paroxysms of humoral asthma. Hence anxiety, which is a continued pain of fear, so universally debilitates the constitution as to occasion a lingering death; which happens much more frequently than is usually supposed; and these victims of continued anxiety are said to die of a broken heart. Other kinds of paleness are described in Class I. 2. 2. 2. M. M. Opium. Wine. Food. Joy. 6. _Palpitatio cordis a timore._ The palpitation of the heart from fear is owing to the weak action of it, and perhaps sometimes to the retrograde exertion of the ventricules and auricles; because it seems to be affected by its association with the capillaries, the actions of which, with those of the arteries and veins, constitute one great circle of associate motions. Now when the capillaries of the skin become torpid, coldness and paleness succeed; and with these are associated the capillaries of the lungs, whence difficult respiration; and with these the weak and retrograde actions of the heart. At the same time the absorbents of the skin, and of the bladder, and of the intestines, sometimes become retrograde, and regurgitate their contents; as appears by the pale urine in large quantities, which attends hysteric complaints along with this palpitation of the heart; and from the cold sweats, and diarrhoea; all which, as well as the hysteric complaints, are liable to be induced or attended by fear. When fear has still more violently affected the system, there have been instances where syncope, and sudden death, or a total stoppage of the circulation, have succeeded: in these last cases, the pain of fear has employed or exhausted the whole of the sensorial power, so that not only those muscular fibres generally exerted by volition cease to act, whence the patient falls down; and those, which constitute the organs of sense, whence syncope; but lastly those, which perform the vital motions, become deprived of sensorial power, and death ensues. See Class. I. 2. 1. 4. and I. 2. 1. 10. Similar to this in some epileptic fits the patient first suddenly falls down, without even endeavouring to save himself by his hands before the convulsive motions come on. In this case the great exertion of some small part in consequence of great irritation or sensation exhausts the whole sensorial power, which was lodged in the extremities of the locomotive nerves, for a short time, as in syncope; and as soon as these muscles are again supplied, convulsions supervene to relieve the painful sensation. See Class III. 1. 1. 7. 7. _Abortio a timore._ Women miscarry much more frequently from a fright, than from bodily injury. A torpor or retrograde motion of the capillary arteries of the internal uterus is probably the immediate cause of these miscarriages, owing to the association of the actions of those vessels with the capillaries of the skin, which are rendered torpid or retrograde by fear. By this contraction of the uterine arteries, the fine vessels of the placenta, which are inserted into them, are detruded, or otherwise so affected, that the placenta separates at this time from the uterus, and the fetus dies from want of oxygenation. A strong young woman, in the fifth or sixth month of her pregnancy, who has since borne many children, went into her cellar to draw beer; one of the servant boys was hid behind a barrel, and started out to surprise her, believing her to be the maid-servant; she began to flood immediately, and miscarried in a few hours. See Sect. XXXIX. 6. 5. and Class I. 2. 1. 14. 8. _Hysteria a timore._ Some delicate ladies are liable to fall into hysteric fits from sudden fright. The peristaltic motions of the bowels and stomach, and those of the oesophagus, make a part of the great circle of irritative motions with those of the skin, and many other membranes. Hence when the cutaneous vessels become torpid from their reverse sympathy with the painful ideas of fear; these of the bowels, and stomach, and oesophagus, become first torpid by direct sympathy with those of the skin, and then feebly and ineffectually invert the order of their motions, which constitutes a paroxysm of the hysteric disease. See Class I. 3. 1. 10. These hysteric paroxysms are sometimes followed by convulsions, which belong to Class III. as they are exertions to relieve pain; and sometimes by death. See Species 9 of this Genus, and Class I. 2. 1. 4. Indigestion from fear is to be ascribed in the same manner to the torpor of the stomach, owing to its association with the skin. As in Class IV. 1. 2. 5. IV. 2. 1. * * * * * ORDO III. _Retrograde Associate Motions._ GENUS II. _Catenated with Sensitive Motions._ SPECIES. 1. _Nausea idealis._ Nausea from disgustful ideas, as from nauseous stories, or disgustful sights, or smells, or tastes, as well as vomiting from the same causes, consists in the retrograde actions of the lymphatics of the throat, and of the oesophagus, and stomach; which are associated with the disgustful ideas, or sensual motions of sight, or hearing, or smell, or taste; for as these are decreased motions of the lymphatics, or of the oesophagus, or stomach, they cannot immediately be excited by the sensorial power of painful sensation, as in that case they ought to be increased motions. So much sensorial power is employed for a time on the disgustful idea, or expended in the production of inactive pain, which attends it, that the other parts of the associated chain of action, of which this disgustful idea is now become a link, is deprived of their accustomed share; and therefore first stop, and then invert their motions. Owing to deficiency of sensorial power, as explained more at large in Sect. XXXV. 1. 3. 2. _Nausea a conceptu._ The nausea, which pregnant women are so subject to during the first part of gestation, is owing to the reverse sympathy between the uterus and stomach, so that the increased action of the former, excited by the stimulus of the growing embryon, which I believe is sometimes attended with sensation, produces decreased actions of the latter with the disagreeable sensation of sickness with indigestion and consequent acidity. When the fetus acquires so much muscular power as to move its limbs, or to turn itself, which is called quickening, this sickness of pregnancy generally ceases. M. M. Calcined magnesia. Rhubarb. Half a grain of opium twice a day. Recumbent posture on a sofa. 3. _Vomitio vertiginosa._ Sea-sickness, the irritative motions of vision, by which we balance ourselves, and preserve our perpendicularity, are disturbed by the indistinctness of their objects; which is either owing to the similarity of them, or to their distance, or to their apparent or unusual motions. Hence these irritative motions of vision are exerted with greater energy, and are in consequence attended with sensation; which, at first is agreeable, as when children swing on a rope; afterwards the irritative motions of the stomach, and of the absorbent vessels, which open their mouths into it, become inverted by their associations with them by reverse sympathy. For the action of vomiting, as well as the disagreeable sensation of sickness, are shewn to be occasioned by defect of the sensorial power; which in this case is owing to the greater expenditure of it by the sense of vision. On the same account the vomiting, which attends the passage of a stone through the ureter, or from an inflammation of the bowels, or in the commencement of some fevers, is caused by the increased expenditure of the sensorial power by the too great action of some links of the associations of irritative motions; and there being in consequence a deficiency of the quantity required for other links of this great catenation. It must be observed, that the expenditure of sensorial power by the retinas of the eyes is very great; which may be estimated by the perpetual use of those organs during our waking hours, and during most of our sleeping ones; and by the large diameters of the two optic nerves, which are nearly the size of a quill, or equal to some of the principal nerves, which serve the limbs. 4. _Vomitio a calculo in uretere._ The action of vomiting in consequence of the increased or decreased actions of the ureter, when a stone lodges in it. The natural actions of the stomach, which consist of motions subject to intermitted irritations from the fluids, which pass through it, are associated with those of the ureter; and become torpid, and consequently retrograde, by intervals, when the actions of the ureter becomes torpid owing to previous great stimulus from the stone it contains; as appears from the vomiting existing when the pain is least. When the motions of the ureter are thus lessened, the sensorial power of association, which ought to actuate the stomach along with the sensorial power of irritation, ceases to be excited into action; and in consequence the actions of the stomach become less energetic, and in consequence retrograde. For as vomiting is a decreased action of the stomach, as explained in Sect. XXXV. 1. 3. it cannot be supposed to be produced by the pain of gravel in the ureter alone, as it should then be an increased action, not a decreased one. The perpetual vomiting in ileus is caused in like manner by the defective excitement of the sensorial power of association by the bowel, which is torpid during the intervals of pain; and the stomach sympathizes with it. See Enteritis, Class II. 1. 2. 11. Does this symptom of vomiting indicate, whether the disease be above or below the valve of the colon? Does not the softer pulse in some kinds of enteritis depend on the sympathy of the heart and arteries with the sickness of the stomach? See Ileus and Cholera. Hence this sickness, as well as the sickness in some fevers, cannot be esteemed an effort of nature to dislodge any offensive material; but like the sea-sickness described above, and in Sect. XX. 4. is the consequence of the associations of irritative or sensitive motions. See Class I. 1. 3. 9. 5. _Vomitio ab insultu paralytico._ Paralytic affections generally commence with vomiting, the same frequently happens from a violent blow with a stick on the head; this curious connection of the brain and stomach has not been explained; as it resembles the sickness in consequence of vertigo at sea, it would seem to arise from a similar cause, viz. from disturbed irritative or sensitive associations. 6. _Vomitio a titillatione faucium._ If the throat be slightly tickled with a feather, a nausea is produced, that is, an inverted action of the mouths of the lymphatics of the fauces, and by direct sympathy an inverted action of the stomach ensues. As these parts have frequently been stimulated at the same time into pleasurable action by the deglutition of our daily aliment, their actions become strongly associated. And as all the food, we swallow, is either moist originally, or mixed with our moist saliva in the mouth; a feather, which is originally dry, and which in some measure repels the moist saliva, is disagreeable to the touch of the fauces; at the same time this nausea and vomiting cannot be caused by the disagreeable sensation simply, as then they ought to have been increased exertions, and not decreased ones, as shewn in Section XXXV. 1. 3. But the mouths of the lymphatics of the fauces are stimulated by the dry feather into too great action for a time, and become retrograde afterwards by the debility consequent to too great previous stimulus. 7. _Vomitio cute sympathetica._ Vomiting is successfully stopped by the application of a blister on the back in some fevers, where the extremities are cold, and the skin pale. It was stopped by Sydenham by producing a sweat on the skin by covering the head with the bed-clothes. See Class IV. 1. 1. 3. and Suppl. I. 11. 6. * * * * * ORDO III. _Retrograde Associate Motions._ GENUS III. _Catenated with Voluntary Motions._ SPECIES. 1. _Ruminatio._ In the rumination of horned cattle the food is brought up from the first stomach by the retrograde motions of the stomach and oesophagus, which are catenated with the voluntary motions of the abdominal muscles. 2. _Vomitio voluntaria._ Voluntary vomiting. Some human subjects have been said to have obtained this power of voluntary action over the retrograde motions of the stomach and oesophagus, and thus to have been able to empty their stomach at pleasure. See Sect. XXV. 6. This voluntary act of emptying the stomach is possessed by some birds, as the pigeon; who has an organ for secreting milk in its stomach, as Mr. Hunter observed; and softens the food for its young by previously swallowing it; and afterwards putting its bill into theirs returns it into their mouths. See Sect. XXXIX. 4. 8. The pelicans use a stomach, or throat bag, for the purpose of bringing the fish, which they catch in the sea to shore, and then eject them, and eat them at their leisure. See Sect. XVI. 11. And I am well informed of a bitch, who having puppies in a stable at a distance from the house, swallowed the flesh-meat, which was given her, in large pieces, and carrying it immediately to her whelps, brought it up out of her stomach, and laid it down before them. 3. _Eructatio voluntaria._ Voluntary eructation. Some, who have weak digestions, and thence have frequently been induced to eruct the quantity of air discharged from the fermenting aliment in their stomachs, have gradually obtained a power of voluntary eructation, and have been able thus to bring up hogsheads of air from their stomachs, whenever they pleased. This great quantity of air is to be ascribed to the increase of the fermentation of the aliment by drawing off the gas as soon as it is produced. See Sect. XXIII. 4. * * * * * ORDO III. _Retrograde Associate Motions._ GENUS. IV. _Catenated with External Influences._ SPECIES. 1. _Catarrhus periodicus._ Periodical catarrh is not a very uncommon disease; there is a great discharge of a thin saline mucous material from the membranes of the nostrils, and probably from the maxillary and frontal sinuses, which recur once a day at exact solar periods; unless it be disturbed by the exhibition of opium; and resembles the periodic cough mentioned below. See Class I. 3. 2. 1. It is probably owing to the retrograde action of the lymphatics of the membranes affected, and produced immediately by solar influence. 2. _Tussis periodica._ Periodic cough, called nervous cough, and tussis serina. It seems to arise from a periodic retrograde action of the lymphatics of the membrane, which lines the air-cells of the lungs. And the action of coughing, which is violently for an hour or longer, is probably excited by the stimulus of the thin fluid thus produced, as well as by the disagreeable sensation attending membranous inactivity; and resembles periodic catarrh not only in its situation on a mucous membrane, but in the discharge of a thin fluid. As it is partly restrainable, it does not come under the name of convulsion; and as it is not attended with difficult respiration, it cannot be called asthma; it is cured by very large doses of opium, see a case and cure in Sect. XXXVI. 3. 9. see Class IV. 2. 4. 6. and seems immediately to be induced by solar influence. 3. _Histeria a frigore._ Hysteric paroxysms are occasioned by whatever suddenly debilitates the system, as fear, or cold, and perhaps sometimes by external moisture of the air, as all delicate people have their days of greater or less debility, see Class IV. 3. 1. 8. 4. _Nausea pluvialis._ Sickness at the commencement of a rainy season is very common among dogs, who assist themselves by eating the agrostris canina, or dog's grass, and thus empty their stomachs. The same occurs with less frequency to cats, who make use of the same expedient. See Sect. XVI. 11. I have known one person, who from his early years has always been sick at the beginning of wet weather, and still continues so. Is this owing to a sympathy of the mucous membrane of the stomach with the mechanical relaxation of the external cuticle by a moister atmosphere, as is seen in the corrugated cuticle of the hands of washing-women? or does it sympathize with the mucous membrane of the lungs, which must be affected along with the mucus on its surface by the respiration of a moister atmosphere? * * * * * SUPPLEMENT TO CLASS IV. _Sympathetic Theory of Fever._ As fever consists in the increase or diminution of direct or reverse associated motions, whatever may have been the remote cause of them, it properly belongs to the fourth class of diseases; and is introduced at the end of the class, that its great difficulties might receive elucidation from the preceding parts of it. These I shall endeavour to enumerate under the following heads, trusting that the candid reader will discover in these rudiments of the theory of fever a nascent embryon, an infant Hercules, which Time may rear to maturity, and render serviceable to mankind. I. Simple fever of two kinds. II. Compound fever. III. Termination of the cold fit. IV. Return of the cold fit. V. Sensation excited in fever. VI. Circles of associated motions. VII. Alternations of cold and hot fits. VIII. Orgasm of the capillaries. IX. Torpor of the lungs. X. Torpor of the brain. XI. Torpor of the heart and arteries. XII. Torpor of the stomach and intestines. XIII. Case of continued fever explained. XIV. Termination of continued fever. XV. Inflammation excited in fever. XVI. Recapitulation. I. _Simple fever._ 1. When a small part of the cutaneous capillaries with their mucous or perspirative glands are for a short time exposed to a colder medium, as when the hands are immersed in iced water for a minute, these capillary vessels and their glands become torpid or quiescent, owing to the eduction of the stimulus of heat. The skin then becomes pale, because no blood passes through the external capillaries; and appears shrunk, because their sides are collapsed from inactivity, not contracted by spasm; the roots of the hair are left prominent from the seceding or subsiding of the skin around them; and the pain of coldness is produced. In this situation, if the usual degree of warmth be applied, these vessels regain their activity; and having now become more irritable from an accumulation of the sensorial power of irritation during their quiescence, a greater exertion of them follows, with an increased glow of the skin, and another kind of pain, which is called the hot-ach; but no fever, properly so called, is yet produced; as this effect is not universal, nor permanent, nor recurrent. 2. If a greater part of the cutaneous capillaries with their mucous and perspirative glands be exposed for a longer time to cold, the torpor or quiescence becomes extended by direct sympathy to the heart and arteries; which is known by the weakness, and consequent frequency of the pulse in cold fits of fever. This requires to be further explained. The movements of the heart and arteries, and the whole of the circulatory vessels, are in general excited into action by the two sensorial powers of irritation, and of association. The former is excited by stimulus, the latter by the previous actions of a part of the vital circle of motions. In the above situation the capillaries act weakly from defect of irritation, which is caused by deficient stimulus of heat; but the heart and arteries act weakly from defect of association, which is owing to the weak action of the capillaries; which does not now excite the sensorial power of association into action with sufficient energy. After a time, either by the application of warmth, or by the increase of their irritability owing to the accumulation of the sensorial power of irritation during their previous quiescence, the capillary vessels and glands act with greater energy than natural; whence the red colour and heat of the skin. The heart and arteries acquire a greater strength of pulsation, and continue the frequency of it, owing to the accumulation of the sensorial power of association during their previous torpor, and their consequent greater associability; which is now also more strongly excited by the increased actions of the capillaries. And thus a fit of simple fever is produced, which is termed Febris irritativa; and consists of a torpor of the cutaneous capillaries with their mucous and perspirative glands, accompanied with a torpor of the heart and arteries; and afterwards of an increased action of all these vessels, by what is termed direct sympathy. This fever, with strong pulse without inflammation, or febris irritativa, described in Class I. 1. 1. 1. is frequently seen in vernal intermittents, as the orgasm of the heart and arteries is then occasioned by their previous state of torpor; but more rarely I believe exists in the type of continued fever, except there be an evident remission, or approximation to a cold fit; at which time a new accumulation of the sensorial power of association is produced; which afterwards actuates the heart and arteries with unnatural vigour; or unless there be some stimulus perpetually acting on the system so as to induce an increased secretion of sensorial power in the brain, as occurs in slight degrees of intoxication. Since without one or other of these circumstances in continued fevers without inflammation, that is, without the additional sensorial power of sensation being introduced, it seems difficult to account for the production of so great a quantity of sensorial power, as must be necessary to give perpetual increase of action to the whole sanguiferous system. 3. On the contrary, while the cutaneous capillaries with their mucous and perspirative glands acquire an increased irritability, as above, by the accumulation of that sensorial power during their previous quiescence, and thus constitute the hot fit of fever; if the heart and arteries do not acquire any increase of associability, but continue in their state of torpor, another kind of simple fever is produced; which is generally of the continued kind, and is termed Febris inirritativa; which consists of a previous torpor of the capillaries of the skin, and of the heart and arteries by direct sympathy with them; and afterwards of an orgasm or increased action of the capillaries of the skin, with a decreased action, or continued torpor, of the heart and arteries by reverse sympathy with them. This orgasm of the cutaneous capillaries, which appears by the blush and heat of the skin, is at first owing to the accumulation of the sensorial power of irritation during their previous torpid state, as in the febris irritata above described; but which is afterwards supported or continued by the reverse sympathy of these capillaries with the torpid state of the heart and arteries, as will be further explained in article 8 of this Supplement. 4. The renovated activity of the capillaries commences as soon or sooner than that of the heart and arteries after the cold fit of irritative fever; and is not owing to their being forced open by the blood being impelled into them mechanically, by the renovated action of the heart and arteries; for these capillaries of the skin have greater mobility than the heart and arteries, as appears in the sudden blush of shame; which may be owing to their being more liable to perpetual varieties of activity from their exposure to the vicissitudes of atmospheric heat. And because in inirritative fevers, or those with arterial debility, the capillaries acquire increased strength, as is evinced by the heat of the skin, while the pulsations of the heart and arteries remain feeble. 5. It was said above, that the cutaneous capillaries, when they were rendered torpid by exposure to cold, either recovered their activity by the reapplication of external warmth; or by their increased irritability, which is caused by the accumulation of that sensorial power during their quiescence. An example of the former of these may be seen on emerging from a very cold bath; which produces a fit of simple fever; the cold fit, and consequent hot fit, of which may be prolonged by continuing in the bath; which has indeed proved fatal to some weak and delicate people, and to others after having been much exhausted by heat and exercise. See Sect. XXXII. 3. 2. An example of the latter may be taken from going into a bath of about eighty degrees of heat, as into the bath at Buxton, where the bather first feels a chill, and after a minute becomes warm, though he remains in the same medium, owing to the increase of irritability from the accumulation of that sensorial power during the short time, which the chilness continued. 6. Hence simple fevers are of two kinds; first, the febris irritativa, or fever with strong pulse; which consists of a previous torpor of the heart, arteries, and capillaries, and a succeeding orgasm of those vessels. Secondly, the febris inirritativa, or fever with weak pulse, which consists of a previous torpor of the heart, arteries, and capillaries; and of a succeeding orgasm of the capillaries, the torpor of the heart and arteries continuing. But as the frequency of the pulse occurs both in the state of torpor, and in that of orgasm, of the heart and arteries; this constitutes a criterion to distinguish fever from other diseases, which are owing to the torpor of some parts of the system, as paresis, and hemicrania. 7. The reader will please to observe, that where the cutaneous or pulmonary capillaries are mentioned, their mucous and perspirative glands are to be understood as included; but that the absorbents belonging to those systems of vessels, and the commencement of the veins, are not always included; as these are liable to torpor separately, as in anasarca, and petechiæ; or to orgasm, or increased action, as in the exhibition of strong emetics, or in the application of vinegar to the lips; yet he will also please to observe, that an increased or decreased action of these absorbents and veins generally occurs along with that of the capillaries, as appears by the dry skin in hot fits of fever; and from there being generally at the same time no accumulation of venous blood in the cutaneous vessels, which would appear by its purple colour. II. _Compound fever._ 1. When other parts of the system sympathize with this torpor and orgasm of the cutaneous capillaries, and of the heart and arteries; the fever-fit becomes more complicated and dangerous; and this in proportion to the number and consequence of such affected parts. Thus if the lungs become affected, as in going into very cold water, a shortness of breath occurs; which is owing to the collapse or inactivity (not to the active contraction, or spasm), of the pulmonary capillaries; which, as the lungs are not sensible to cold, are not subject to painful sensation, and consequent shuddering, like the skin. In this case after a time the pulmonary capillaries, like the cutaneous ones, act with increased energy; the breathing, which was before quick, and the air thrown out at each respiration in less quantity, and cool to the back of the hand opposed to it, now becomes larger in quantity, and warmer than natural; which however is not accompanied with the sensation of heat in the membrane, which lines the air-vessels of the lungs, as in the skin. 2. One consequence of this increased heat of the breath is the increased evaporation of the mucus on the tongue and nostrils. A viscid material is secreted by these membranes to preserve them moist and supple, for the purposes of the senses of taste and of smell, which are extended beneath their surfaces; this viscid mucus, when the aqueous part of it is evaporated by the increased heat of the respired air, or is absorbed by the too great action of the mucous absorbents, adheres closely on those membranes, and is not without difficulty to be separated from them. This dryness of the tongue and nostrils is a circumstance therefore worthy to be attended to; as it shews the increased action of the pulmonary capillaries, and the consequent increased heat of the expired air; and may thus indicate, when colder air should be admitted to the patient. See Class I. 1. 3. 1. The middle part of the tongue becomes dry sooner, and recovers its moisture later, than the edges of it; because the currents of respired air pass most over the middle part of it. This however is not the case, when the dryness of the tongue is owing only to the increased mucous absorption. When however a frequent cough attends pulmonary inflammation, the edges of the tongue are liable to be as much furred as the middle of it; as during the action of coughing the middle of the tongue is depressed, so as to form half a cylinder, to give a greater aperture for the emission of air from the larynx; and the edges of it become thus as much exposed to the currents of air, as the middle parts of it. 3. When the internal capillaries or glands sympathize with the cutaneous capillaries; or when any of them are previously affected with torpor, and the external or cutaneous capillaries are affected secondarily; other symptoms are produced, which render the paroxysms of fever still more complicate. Thus if the spleen or pancreas are primarily or secondarily affected, so as to be rendered torpid or quiescent, they are liable to become enlarged, and to remain so even after the extinction of the fever-fit. These in some intermittent fevers are perceptible to the hand, and are called ague-cakes; their tumour seems to be owing to the permanent torpor of the absorbent system, the secerning vessels continuing to act some time afterwards. If the secretory vessels of the liver are affected first with torpor, and afterwards with orgasm, a greater secretion of bile is produced, which sometimes causes a diarrhoea. If a torpor of the kidneys, and of the absorbents of the bladder occurs, either primarily, or by sympathy with the cutaneous capillaries, the urine is in small quantity and pale, as explained in Class I. 2. 2. 5.; and if these secretory vessels of the kidneys, and the absorbents of the bladder act more strongly than natural afterwards by their increased irritability or associability, the urine becomes in larger quantity, and deeper coloured, or deposits its earthy parts, as in Class I. 1. 2. 4. which has been esteemed a favourable circumstance. But if the urine be in small quantity, and no sediment appears in it, after the hot fit is over; it shews, that the secerning vessels of the kidneys and the absorbent vessels of the bladder have not regained the whole of their activity, and thence indicates a greater tendency to a return of the cold fit. 4. When the stomach is affected with torpor either primarily; or secondarily by its sympathy with the cutaneous capillaries; or with some internal viscus; sickness occurs, with a total want of appetite to any thing solid; vomiting then supervenes, which may often be relieved by a blister on the skin, if the skin be cool and pale; but not if it be hot and flushed. The intestines cease to perform their office of absorption from a similar torpor; and a diarrhoea supervenes owing to the acrimony of their putrid, or of their acid contents. The loose undigested or fetid stools indicate the inability of the intestines to perform their proper office; as the mucus and gastric acid, which are vomited up, does that of the stomach; this torpor of the stomach is liable to continue after the cold paroxysm ceases, and to convert intermittent fevers into continued ones by its direct sympathy with the heart and arteries. See article 10 of this Supplement. 5. If the meninges of the brain sympathize with other torpid parts, or are primarily affected, delirium, stupor, and perhaps hydrocephalus internus occur, see Class II. 1. 7. 1. and I. 2. 5. 10; and sometimes the pulse becomes slow, producing paresis instead of fever. But if the membranes, which cover the muscles about the head, or of the pericranium, become torpid by their sympathy with other torpid parts, or are primarily affected, a head-ach supervenes; which however generally ceases with the cold paroxysm of fever. For as when the sensorial power of volition is exhausted by labour, a few hours, or half a solar day, passed in sleep recruits the system by accumulation of this sensorial power; so when the sensorial power of irritation is exhausted, one or two solar or lunar days of rest or quiescence of the affected part will generally restore its action by accumulation of irritability, and consequent increase of association, as in hemicrania, Class IV. 2. 2. 8. But when the heart and arteries become torpid, either primarily, or by their sympathy with the stomach, this accumulation of the sensorial power of irritation can take place but slowly; _as to rest is death_! This explains the cause of the duration of fevers with weak pulse, which continue a quarter, or half, or three quarters, or a whole lunation, or still longer, before sufficient accumulation of irritability can be produced to restore their natural strength of action. 6. If the absorbent vessels, which are spread around the neck of the bladder, become torpid by their direct sympathy with the absorbents of the skin in cold fits of fever; the urine, which is poured into the bladder in but small quantity from the torpid kidneys, has nevertheless none of its aqueous saline part reabsorbed; and this saline part stimulates the bladder to empty itself frequently, though the urine is in small quantity. Which is not therefore owing to any supposed spasm of the bladder, for the action of it in excluding the urine is weak, and as much controlable by the will as in ordinary micturition. 7. If the beginnings or absorbent mouths of the venous system remain torpid, petechiæ or vibices are produced in fevers, similar to those which are seen in scurvy without fever. If the skin was frequently moistened for an hour, and at the same time exposed to the common air, or to oxygen gas, it might contribute to turn the black colour of these points of extravasated blood into scarlet, and thus by increasing its stimulus facilitate its reabsorption? For oxygen gas penetrates moist animal membranes though not dry ones, as in the lungs during respiration. 8. When the sensorial power of sensation is introduced into the arterial system, other kinds of compound fevers are produced, which will be spoken of in their place. III. _Termination of the cold Fit._ 1. If all the parts, which were affected with torpor, regain their irritability, and associability, the cold paroxysm of fever ceases; but as some of the parts affected were previously accustomed to incessant action, as the heart and arteries, and others only to intermitted action, as the stomach and intestines; and as those, which are subjected during health to perpetual action, accumulate sensorial power faster, when their motions are impeded, than those which are subjected to intermitted action; it happens, that some of the parts, which were affected with torpor during the cold fit, recover their irritability or associability sooner than others, and more perfectly, or acquire a greater quantity of them than natural; as appears by the partial heat and flushings previous to the general hot fit. Hence if all the parts, which were previously torpid, regain their due degree of irritability, or of associability, the disease is removed, and health restored. If some or all of them acquire more than their natural degree of these sensorial powers; increased actions, and consequent increased secretions, and greater heat occur, and constitute the hot fit of fever. If after this hot fit of fever all the parts, which had acquired too great irritability, or associability, regain their natural degree of it; the disease is removed, and health restored. But if some of these parts do not regain their natural degree of these sensorial powers, the actions of those parts remain imperfect, and are more or less injurious to the system, according to the importance of their functions. 2. Thus if a torpor of the heart and arteries remains; the quick pulse without strength, which began in the cold fit, persists; and a continued fever is produced. If the torpor of the stomach and intestines remains, which are known by sickness and undigested stools, the fever is liable to be of considerable length and danger; the same if the kidnies and absorbent system retain some degree of torpor, as is shewn by the pale urine in not unusual quantity. If part of the absorbent system remains torpid, as the absorbent vessels of the spleen, a tumour of that viscus occurs, which may be felt by the hand; the same sometimes happens to the liver; and these from their tendency to more complete torpor are afterwards liable to give occasion to a return of the cold fit. If the cellular absorbents do not completely recover their activity, a pale and bloated countenance with swelled legs mark their want of action. 3. As the termination of the cold fit is owing to the accumulation of the sensorial power of irritation and of association during the previous quiescence of the system; and as those parts, which are in perpetual action during health, are more subject to this accumulation during their torpor, or quiescence; one should have imagined, that the heart and arteries would acquire this accumulation of sensorial power sooner or in greater degree than other parts. This indeed so happens, where the pulse is previously strong, as in febris irritativa; or where another sensorial power, as that of sensation, is exerted on the arterial system, as in inflammations. The heart and arteries in these cases soon recover from their torpor, and are exerted with great violence. Many other parts of the system subject to perpetual motion in health may rest for a time without much inconvenience to the whole; as when the fingers of some people become cold and pale; and during this complete rest great accumulation of irritability may be produced, But where the heart and arteries are previously feeble, they cannot much diminish their actions, and certainly cannot rest entirely, for that would be death; and therefore in this case their accumulation of the sensorial power of irritation or of association is slowly produced, and a long fever supervenes in consequence; or sudden death, as frequently happens, terminates the cold fit. Whence it appears, that in fevers with weak pulse, if the action of the heart, arteries, and capillaries could be diminished, or stopped for a short time without occasioning the death of the patient, as happens in cold bathing, or to persons apparently drowned, that a great accumulation of the sensorial powers of irritation or of association might soon be produced, and the pulse become stronger, and consequently slower, and the fever cease. Hence cold ablution may be of service in fevers with weak pulse, by preventing the expenditure and producing accumulation of the sensorial power of irritation or association. Stupor may be useful on the same account. Could a centrifugal swing be serviceable for this purpose, either by placing the head or the feet in the outward part of the circle, as described in Art. 15. 7. of this Supplement? IV. _Return of the cold Fit._ 1. If the increased action of the cutaneous and pulmonary capillaries, and of the heart and arteries, in febris irritativa continues long and with violence, a proportional expenditure or exhaustion of sensorial power occurs; which by its tendency to induce torpor of some part, or of the whole, brings on a return of the cold fit. 2. Another cause which contributes to induce torpor of the whole system by the sympathy of its parts with each other, is the remaining torpor of some viscus; which after the last cold paroxysm had not recovered itself, as of the spleen, liver, kidnies, or of the stomach and intestines, or absorbent vessels, as above mentioned. 3. Other causes are the deficiency of the natural stimuli, as hunger, thirst, and want of fresh air. Other causes are great fatigue, want of rest, fear, grief, or anxiety of mind. And lastly, the influence of external ethereal fluids, as the defect of external heat, and of solar or lunar gravitation. Of the latter the return of the paroxysms of continued fevers about six o'clock in the evening, when the solar gravitation is the least, affords an example of the influence of it; and the usual periods of intermittents, whether quotidian, tertian, or quartan, which so regularly obey solar or lunar days, afford instances of the influence of those luminaries on these kinds of fevers. 4. If the tendency to torpor of some viscus is considerable, this will be increased at the time, when the terrene gravitation is greatest, as explained in the introduction to Class IV. 2. 4. and may either produce a cold paroxysm of quotidian fever; or it may not yet be sufficient in quantity for that purpose, but may nevertheless become greater, and continue so till the next period of the greatest terrene gravitation, and may then either produce a paroxysm of tertian fever; or may still become greater, and continue so till the next period of greatest terrene gravitation, and then produce a paroxysm of quartan ague. And lastly, the periodical times of these paroxysms may exceed, or fall short of, the time of greatest diurnal terrene gravitation according to the time of day, or period of the moon, in which the first fit began; that is, whether the diurnal terrene gravitation was then in an increasing or decreasing state. V. _Sensation excited in Fever._ 1. A curious observation is related by Dr. Fordyce in his Tract on Simple fever, page 168. He asserts, that those people, who have been confined some time in a very warm atmosphere, as of 120 or 130 degrees of heat, do not feel cold, nor are subject to paleness of their skins, on coming into a temperature of 30 or 40 degrees; which would produce great paleness and painful sensation of coldness in those, who had been some time confined in an atmosphere of only 86 or 90 degrees. Analogous to this, an observing friend of mine assured me, that once having sat up to a very late hour with three or four very ingenious and humorous companions, and drank a considerable quantity of wine; both contrary to his usual habits of life; and being obliged to rise early, and to ride a long journey on the next day; he expected to have found himself weak and soon fatigued; but on the contrary he performed his journey with unusual ease and alacrity; and frequently laughed, as he rode, at the wit of the preceding evening. In both these cases a degree of pain or pleasure actuated the system; and thus a sensorial power, that of sensation, was superadded to that of irritation, or volition. See Sect. XXXIV. 2. 6. 2. Similar to this, when the energetic exertions of some parts of the system in the hot fit of fever arise to a certain excess, a degree of sensation is produced; as of heat, which particularly increases the actions of the cutaneous vessels, which are more liable to be excited by this stimulus. When this additional sensorial power of sensation exists to a greater degree, the pulse, which was before full, now becomes hard, owing to the inflammation of the vasa vasorum, or coats of the arteries. In these cases, whether there is any topical inflammation or not, the fever ceases to intermit; but nevertheless there are daily remissions and exacerbations of it; which recur for the most part about six in the evening, when the solar gravitation is the least, as mentioned in Sect. XXXVI. 3. 7. 3. Thus the introduction of another sensorial power, that of sensation, converts an intermittent fever into a continued one. If it be attended with strong pulse, it is termed febris sensitiva irritata, or pyrexia, or inflammation; if with a weak pulse, it is termed febris sensitiva inirritata, or typhus gravior, or malignant fever. The seat of the inflammation is in the glandular or capillary system, as it consists in the secretion of new fluids, or new fibres, which form new vessels, as they harden, like the silk of the silk-worm. See Art. 15. of this Supplement. VI. _Circles of irritative Associate Motions._ 1. There are some associate motions, which are perpetually proceeding in our waking hours, and are catenated by their first link, or in some subsequent parts of the chain, with the stimuli or the influence of external things; which we shall here enumerate, as they contribute to the knowledge of fever. Of these are the irritative ideas, or sensual motions of the organs of sense, and the muscular motions associated with them; which, when the chain is disturbed or interrupted, excite the sensorial power of sensation, and proceed in confusion. Thus if the irritative ideas of sight are disturbed, the paralactic motions of objects, which in general are unperceived, become sensible to us; and the locomotive muscles associated with them, which ought to preserve the body erect, stagger from this decrease or interruption of the sensorial power of association; and vertigo is produced. When the irritative sensual motions, or ideas, belonging to one sense are increased or diminished, the irritative sensual motions, or ideas, of the other senses are liable to become disturbed by their general catenations; whence occur noises in the ears, bad tastes in the mouth, bad odours, and numbness or tingling of the limbs, as a greater or less number of senses are affected. These constitute concomitant circles of disturbed irritative ideas; or make a part of the great circle of irritative ideas, or motions of the organs of sense; and when thus disturbed occasion many kinds of hallucination of our other senses, or attend on the vertigo of vision. 2. Another great circle of irritative associated motions consists of those of the alimentary canal; which are catenated with stimuli or with influences external to the system, but continue to be exerted in our sleeping as well as in our waking hours. When these associations of motion are disturbed by the too great or too small stimulus of the food taken into the stomach, or by the too great excess or deprivation of heat, or by indigestible substances, or by torpor or orgasm occasioned by their association with other parts, various diseases are induced under the names of apepsia, hypochondriasis, hysteria, diarrhoea, cholera, ileus, nephritis, fever. 3. A third circle of irritative associate motions consists of those of the absorbent system; which may be divided into two, the lacteals, and the lymphatics. When the stomach and intestines are recently filled with food and fluid, the lacteal system is stimulated into great action; at the same time the cellular, cutaneous, and pulmonary lymphatics act with less energy; because less fluid is then wanted from those branches, and because more sensorial power is expended by the lacteal branch. On this account these two systems of absorbents are liable to act by reverse sympathy; hence pale urine is made after a full dinner, as less of the aqueous part of it is imbibed by the urinary lymphatics; and hence the water in anasarca of the lungs and limbs is speedily absorbed, when the actions of the lacteals of the stomach or intestines are weakened or inverted by the exhibition of those drugs, which produce nausea, or by violent vomiting, or violent cathartics. Hence in diabetes the lacteal system acts strongly, at the same time that the urinary lymphatics invert their motions, and transmit the chyle into the bladder; and in diarrhoea from crapula, or too great a quantity of food and fluid taken at a time, the lacteals act strongly, and absorb chyle or fluids from the stomach and upper intestines; while the lymphatics of the lower intestines revert their motions, and transmit this over-repletion into the lower intestines, and thus produce diarrhoea; which accounts for the speedy operation of some cathartic drugs, when much fluid is taken along with them. 4. Other circles of irritative associate motions of great importance are those of the secerning system; of these are the motions of the larger congeries of glands, which form the liver, spleen, pancreas, gastric glands, kidneys, salivary glands, and many others; some of which act by direct and others by reverse sympathy with each other. Thus when the gastric glands act most powerfully, as when the stomach is filled with food, the kidneys act with less energy; as is shewn by the small secretion of urine for the first hour or two after dinner; which reverse sympathy is occasioned by the greater expenditure of sensorial power on the gastric glands, and to the newly absorbed fluids not yet being sufficiently animalized, or otherwise prepared, to stimulate the secretory vessels of the kidneys. But those very extensive glands, which secrete the perspirable matter of the skin and lungs, with the mucus, which lubricates all the internal cells and cavities of the body, claim our particular attention. These glands, as well as all the others, proceed from the capillary vessels, which unite the arteries with the veins, and are not properly a part of them; the mucous and perspirative glands, which arise from the cutaneous and pulmonary capillaries, are associated by direct sympathy; as appears from immersion in the cold bath, which is therefore attended with a temporary difficult respiration; while those from the capillaries of the stomach and heart and arteries are more generally associated by reverse sympathy with those of the cutaneous capillaries; as appears in fevers with weak pulse and indigestion, and at the same time with a hot and dry skin. The disturbed actions of this circle of the associate motions of the secerning system, when the sensorial power of sensation is added to that of irritation, frequently produces inflammation, which consists in the secretion of new fluids or new vessels. Nevertheless, if these disturbed actions be of the torpid kind, the pain, which attends them, is seldom productive of inflammation, as in hemicrania; but is liable to excite voluntary actions, and thus to expend much sensorial power, as in the shuddering in cold fits of fever, or in convulsions; or lastly the pain itself, which attends torpid actions, is liable to expend or exhaust much sensorial power without producing any increased actions; whence the low pulse, and cold extremities, which usually attend hemicrania; and hence when inert, or inactive sensation attends one link of associated action, the succeeding link is generally rendered torpid, as a coldness of the cheek attends tooth-ach. 5. A fifth important circle of irritative motions is that of the sanguiferous system, in which the capillary vessels are to be included, which unite the arterial and venous systems, both pulmonary and aortal. The disturbed action of this system of the heart and arteries, and capillaries, constitute simple fever; to which may be added, that the secerning and absorbent vessels appending to the capillaries, and the bibulous mouths of the veins, are in some measure at the same time generally affected. 6. Now, though the links of each of these circles of irritative motions are more strictly associated together, yet are they in greater or less degree associated or catenated with each other by direct or reverse sympathy. Thus the sickness, or inverted irritative motions of the stomach, are associated or catenated with the disturbed irritative ideas, or sensual motions, in vertigo; as in sea-sickness. This sickness of the stomach is also associated or catenated with the torpor of the heart and arteries by direct sympathy, and with the capillaries and absorbents by reverse sympathy; and are thus all of them liable occasionally to be disturbed, when one of them is diseased; and constitute the great variety of the kinds or symptoms of fevers. VII. _Alternation of the cold and hot Fits._ 1. When any cause occurs, which diminishes to a certain degree the supply of sensorial power in respect to the whole system; as suppose a temporary inexertion of the brain; what happens? First, those motions are exerted with less energy, which are not immediately necessary to life, as the locomotive muscles; and those ideas, which are generally excited by volition; at the same time this deficiency of voluntary motion is different from that which occurs in sleep; as in that the movements of the arterial system are increased in energy though not in frequency. Next, the motions of the alimentary canal become performed with less energy, or cease altogether; and a total want of appetite to solid food occurs, or sickness, or a diarrhoea occasioned by the indigested aliment. Then the absorbent vessels cease to act with their due energy; whence thirst, and pale urine, though in small quantities. Fourthly, the secerning vessels become affected by the general diminution of sensorial power; whence all the secreted fluids are produced in less quantity. And lastly, the sanguiferous canals feel the general torpor; the pulsations of the heart and arteries become feeble, and consequently quick; and the capillaries of the skin become inactive, acquire less blood from the arteries, and are consequently paler and shrunk. In this last circumstance of the torpor of the sanguiferous system consists inirritative fever; as all the others are rather accidental or concomitant symptoms, and not essential ones; as fewer or more of them may be present, or may exist with a greater or less degree of inactivity. 2. Now as the capillaries of the skin are exposed to greater varieties of heat and cold, than the heart and arteries, they are supposed to be more mobile, that is, more susceptible of torpor or exertion, or to inflammation, by external stimuli or influences, than the other parts of the sanguiferous system; and as the skin is more sensible to the presence of heat, than the internal parts of the body, the commencement of the cold paroxysms of fever generally either first exists in, or is first perceived by, the coldness and paleness of the skin; and the commencement of the hot fits by the heat and redness of it. 3. The accumulation of sensorial power occurs in these organs soonest, and in greatest quantity, during their quiescence, which were most perpetually in action during health; hence those parts of the system soonest recover from torpor in intermittent fever, and soonest fall into the contrary extreme of increased activity; as the sanguiferous system of the heart and arteries and capillaries. But of these the capillaries seem first to acquire a renovation of their action, as the heat of the skin becomes first renewed, as well as increased beyond its natural quantity, and this in some parts sooner than in others; which quantity of heat is however not to be estimated simply by the rise of the mercury in the thermometer, but also by the quantity carried away into the atmosphere, or diffused amongst other bodies in a given time; as more heat passes through water, which boils vehemently, than when it boils gently, though the rise of the thermometer in both cases continues the same. This fact may be known by boiling an egg in water, the white of which coagulates in much less time, if the water boils vehemently, than if it boils moderately, though the sensible heat of the water is the same in both cases. Another cause, which induces the cutaneous capillaries to renew their actions sooner than the heart and arteries after immersion in the cold bath, is, that their torpor was occasioned by defect of irritation; whereas that of the heart and arteries was occasioned by defect of association; which defect of association was owing to the decreased actions of the capillaries, and is now again excited by their renewed action; which excitement must therefore be subsequent to that increased action of the capillaries; and in consequence the increased action of the heart and arteries at the commencement of the hot fit of some fevers is subsequent to the increased action of the cutaneous capillaries. There is, however, in this case an accumulation of the sensorial power of association in the heart and arteries, which must contribute to increase their orgasm in the hot fit, as well as the increased excitement of it by the increased action of the capillaries. 4. Now this increased action of the system, during the hot fit, by exhausting the sensorial powers of irritation and association, contributes to induce a renewal of the cold paroxysm; as the accumulation of those sensorial powers in the cold fit produces the increased actions of the hot fit; which two states of the system reciprocally induce each other by a kind of libration, or a plus and minus, of the sensorial powers of irritation and association. If the exhaustion of sensorial power during the hot fit of fever only reduces the quantity of irritability and associability to its natural standard, the fever is cured, not being liable to return. If the quantity of these sensorial powers be reduced only so much, as not to produce a second cold fit during the present quantity of external stimuli or influences; yet it may be so far reduced, that a very small subtraction of stimulus, or of influence, may again induce a cold fit; such as the coldness of the night-air, or the diminution of solar or lunar gravitation, as in intermittent fevers. 5. Another cause of the renovation of the cold fits of fever is from some parts of the system not having completely recovered from the former cold paroxysm; as happens to the spleen, liver, or other internal viscus; which sometimes remains tumid, and either occasions a return of the cold fit by direct sympathy with other parts of the body, or by its own want of action causes a diminution of the general quantity of heat, and thus facilitates the renovation of the torpor of the whole system, and gives cause to intermittent fevers catenated with lunar or solar influence. VIII. _Orgasm of the Capillaries._ As the remaining torpor of some less essential part of the system, as of the spleen, when the hot fit ceases, produces after one, two, or three days a return of cold fit by direct sympathy with the cutaneous capillaries, when joined with some other cause of torpor, as the defect of solar or lunar influences, or the exposure to cold or hunger, and thus gives origin to intermittent fever; so the remaining torpor of some more essential parts of the system, as of the stomach and intestines, is probably the cause of the immediate recurrence of the cold paroxysm, at the time the hot one ceases, by their direct sympathy with the cutaneous capillaries, without the assistance of any other cause of torpor; and thus produces remittent fever. And lastly the remaining torpor of some still more essential parts of the system, as the heart and arteries, after the hot fit ought to cease, is liable by reverse sympathy with the cutaneous capillaries to continue their orgasm, and thus to render a fever continual, which would otherwise remit or intermit. Many difficulties here occur, which we shall endeavour to throw some light upon, and leave to future investigation; observing only that difficulties were to be expected, otherwise fevers would long since have been understood, as they have employed the unremitted attention of the physicians of all ages of the world. 1. Why do the same parts of successive trains of action sometimes affect each other by direct, and sometimes by reverse sympathy?--1st, When any irritative motion ceases, or becomes torpid, which was before in perpetual action; it is either deprived of its usual stimulus, and thence the sensorial power of irritation is not excited; or it has been previously too much stimulated, and the sensorial power has been thus exhausted. In the former case an accumulation of sensorial power soon occurs, which is excitable by a renewal of the stimulus; as when the fingers, which have been immersed some time in snow, are again exposed to the usual warmth of a room. Or, secondly, the sensorial power of irritation becomes so much accumulated, that the motions, which were torpid, are now performed by less stimulus than natural; as appears by the warmth, which soon occurs after the first chill in going into frosty air, or into the bath at Buxton, which is about eighty degrees of heat. Or, lastly, this accumulation of the sensorial power of irritation so far abounds, that it increases the action of the next link of the associated train or tribe of motions; thus on exposing the skin to cold air, as in walking out in a frosty morning, the actions of the stomach are increased, and digestion strengthened. But where the torpor of some irritative motion is owing to the previous exhaustion of the sensorial power of irritation by too great stimulus, the restoration of it occurs either not at all, or much more slowly than in the former instances; thus after intoxication the stomach is very slow in recovering its due quantity of the sensorial power of irritation, and never shews any accumulation of it. 2. When an associate motion, as described in the introduction to Class IV. 1. 1. acts with less energy, the sensorial power of association is either not sufficiently excited by the preceding fibrous motions; or it has been expended or exhausted by the too violent actions of the preceding fibrous motions. In the former case there occurs an accumulation of the sensorial power of association; exactly as, where the usual stimulus is withdrawn, there occurs an accumulation of the sensorial power of irritation. Thus when the actions of the capillaries of the skin are diminished by immersion in cold water, the capillaries of the lungs are rendered torpid by the want of the excitement of the sensorial power of association, owing to the lessened actions of the previous fibrous motions, namely, of those of the skin. Nevertheless as soon as the capillaries of the skin regain their increased activity by the accumulation of the sensorial power of irritation, these capillaries of the lungs act with greater energy also owing to their accumulated sensorial power of association. These are instances of direct sympathy, and constitute the cold and hot paroxysms of intermittent fever; or the first paroxysm of a continued one. 3. When the first link of a train of associated motions, which is subject to perpetual action, becomes a considerable time torpid for want of being excited by the previous exertions of the irritative motions, with which it is catenated; the sensorial power of association becomes accumulated in so great a degree as to affect the second link of the train of associated motions, and to excite it into stronger action. Thus when the stomach is rendered torpid by contagious matter swallowed into it mixed with the saliva, the heart and arteries act more feebly; because the sensorial power of association, which used to be excited by the fibrous motions of the stomach, is not now excited; and in consequence the motions of the heart and arteries act only by the sensorial power of irritation, which is excited by the stimulus of the blood. But during this torpor of the stomach, and less action of the heart and arteries, so great an accumulation of the sensorial powers of irritation and of association occurs, that it adds to the action of the next link of this vital circle of actions, that is, to that of the cutaneous capillaries. Whence in this situation the torpor of the stomach occasions a diminished action of the heart and arteries by direct sympathy, and may be said to occasion an increased one of the cutaneous capillaries by reverse sympathy; which constitute continued fever with weak pulse. Nor is this increased action of the capillaries in consequence of the decreased action of the heart and arteries, as in fevers with weak pulse, a single fact in the animal economy; though it exists in this case in the greatest degree or duration, because the heart and arteries are perpetually in greater action than any other part of the system. But a similar circumstance occurs, when the stomach is rendered inactive by defective excitement of the sensorial power of association, as in sea-sickness, or in nephritis. In these cases the sensorial power of association becomes much accumulated in the stomach, and seems by its superabundance to excite the absorbent system, which is so nearly connected with it, into great increase of action; as is known by the great quantity frequently in these situations rejected by vomit, which could not otherways be supplied. It is probable the increase of digestion by walking in frosty air, with many other animal facts, may by future observations be found to be dependent on this principle, as well as the increased action of the capillaries in continued fevers with weak pulse. Whereas in continued fever with strong pulse, which may perhaps occur sometimes on the first day even of the plague, the stomach with the heart and arteries and the capillaries act by direct sympathy; that is, the stomach is excited into stronger action by increased irritation owing to the stimulus of contagious matter; these stronger irritative motions of the stomach excite a greater quantity of the sensorial power of association, which then actuates the heart and arteries with greater energy, as these are catenated with the stomach; and in the same manner the increased actions of the heart and arteries excite a greater quantity of the sensorial power of association, which actuates the cutaneous capillaries with increase of energy. See Class IV. 1. 1. 4. I shall dwell a little longer on this intricate subject. The commencement of fever-fits is known by the inactivity of the cutaneous capillaries, which inactivity is observable by the paleness and coldness of the skin, and also by the pain of coldness, which attends it. There is nevertheless in most cases, except those which are owing to exposure to external cold, a torpor of the capillaries of some internal viscus preceding this inactivity of the cutaneous capillaries; which is known, by the tumour or hardness of the viscus, or by an aching pain of it. The capillaries of the lungs are at the same time rendered inactive or torpid, as appears by the difficulty of breathing, and coldness of the breath in cold fits of fever, and in going into the cold bath; but the lungs are not affected with the pain either of coldness or of torpor. One cause of this synchronous or successive inactivity of the cutaneous capillaries, in consequence of the previous torpor of some internal viscus, may be owing to the deficiency of heat; which must occur, when any part becomes inactive; because the secretions of that part cease or are lessened, and the quantity of heat of it in consequence. But the principal cause of it I suppose to be owing to the defect of the sensorial power of association; which power of association is excited by some previous or concomitant motions of the parts of every great circle of actions. This appears on going into the cold bath, because the shortness of breath instantly occurs, sooner than one can conceive the diminution of the heat of the skin could affect the lungs by the want of its stimulus; but not sooner than the defect of the sensorial power of association could affect them; because this must cease to be excited into action on the instant that the cutaneous capillaries cease to act; whence in the first moment of contact of the cold water the cutaneous capillaries cease to act from defect of irritation; which is caused by defect of the stimulus of heat; and in the second moment the capillaries of the lungs cease to act from the defect of association; which is caused by the defect of the motions of the cutaneous capillaries. Thus the universal torpor in the cold paroxysm of fever is an example of direct sympathy, though occasioned in part by defect of irritation, and in part by defect of association. 5. Thus in walking out in a frosty morning the skin is cooled by the contact of the cold air, whence the actions of its capillaries are diminished for want of their usual stimulus of heat to excite a sufficient quantity of the sensorial power of irritation. Hence there is at first a saving of sensorial power of irritation for the purpose of actuating the other parts of the system with greater energy. Secondly the sensorial power of association, which used to be excited by the motions of the cutaneous capillaries, is now not so powerfully excited; and in consequence the parts, which constitute the next links of the circles of associated motions, are for a time actuated with less energy, and a temporary general chillness succeeds; which is so far similar to the cold fit of intermittent fever. In this situation there is a curious circumstance occurs, which merits peculiar attention: after a short time, though the external skin continues cool by its exposure to the cold air, and the actions of its capillaries are consequently diminished, yet the capillaries of the stomach act with greater energy; as is known by increased digestion and consequent hunger. This is to be ascribed to the accumulation of the sensorial power of irritation, which now excites by its superabundance, or overflowing, as it were, the stomach into increased action; though it is at the same time excited less powerfully than usual by the sensorial power of association. Thus the accumulation of the sensorial power of irritation in the vessels of the skin increases in this case the action of the stomach, in the same manner as an accumulation of the sensorial power of association in the heart and arteries in fevers with weak pulse increases the action of the capillaries. If nevertheless the coldness of the skin be too long continued, or exists in too great a degree, so as in some measure to impair the life of the part, no further accumulation of the sensorial power of irritation occurs; and in consequence the actions of the stomach become less than natural by the defect of the sensorial power of association; which has ceased to be excited by the want of action of the cutaneous capillaries. Whence continued coldness of the feet is accompanied with indigestion and heartburn. See Class IV. 2. 1. 6. 6. Similar to this when the actions of the stomach are rendered torpid by the previous stimulus of a violent emetic, and its motions become retrograde in consequence, a great quantity of sensorial power is exerted on the lymphatics of the lungs, and other parts of the body; which excites them into greater direct action, as is evinced by the exhibition of digitalis in anasarca. In this situation I suppose the emetic drug stimulates the muscular fibres of the stomach into too great action; and that in consequence a great torpor soon succeeds; and that this inaction of the muscular parts of the stomach is not followed by much accumulation of the sensorial power of irritation; because that sensorial power is in great measure exhausted by the previous excessive stimulus. But the lymphatics of the stomach have their actions lessened by defect of the sensorial power of association, which is not now excited into action, owing to the lessened motions of the muscular parts of it, with which the lymphatics are associated. The sensorial power of association becomes therefore accumulated in these lymphatics of the stomach, because it is not excited into action; exactly as the power of irritation becomes accumulated in the hand, when immersed in snow; and this accumulated sensorial power of association excites the lymphatic of the lungs and of other parts, which are most nearly associated with those of the stomach, into more energetic actions. Thus the muscular fibres of the stomach act with the lymphatics of that organ in direct sympathy; and the lymphatics of the stomach act in reverse sympathy with those of the lungs and of other parts of the body; the former of which is caused by defect of the excitement of the sensorial power of association, and the latter by the accumulation of it. Besides the efficient cause, as above explained, the final cause, or convenience, of these organic actions are worthy our attention. In this case of an acrid drug swallowed into the stomach the reverted actions of the muscular fibres of the stomach tend to eject its enemy; the reverted actions of its lymphatics pour a great quantity of fluids into the stomach for the purpose of diluting or washing off the noxious drug; and the increased actions of the other lymphatics supply these retrograde ones of the stomach with an inconceivable supply of fluids, as is seen in Ileus and Cholera. 7. The inquisitive reader will excuse my continuing this subject, though perhaps with some repetitions, as it envelopes the very essence of fever. When the first link of a train of actions is excited by excessive stimulus, or excessive irritability, and thus acts with unusual energy by the increased quantity of irritation, these increased motions excite a greater quantity of the sensorial power of association, which causes increased motions in the second link, which is catenated with the first; and then the excessive action of this second link excites also a greater quantity of the sensorial power of association, which increases the motions of the third link of this chain of association, and thus the increase of the stimulus on the irritative motions, to which the chain of association is catenated, increases the action of the whole chain or circle of associated motions. After a time the irritative motions become torpid by expenditure of the sensorial power of irritation, and then the power of association also becomes less exerted, both because it has been in part exhausted by too great action, and is now less excited by the lessened action of the irritative motions, which used to excite it. These are both instances of direct sympathy, and frequently constitute the cold and hot fit of intermittents. But though the accumulation of the sensorial power of irritation during the quiescence of some motion owing to want of stimulus generally induces torpor in the first link of the train of associated motions catenated with it; as the capillaries of the lungs become torpid immediately on immersion of the skin into cold water; yet in some situations an orgasm or excess of action is produced in the first link of the associated motions thus catenated with irritative ones; as in the increased action of the stomach, when the skin is for a time exposed to cold air; which may in part be ascribed to the general increase of action of the whole system, owing to the diminished expenditure of sensorial power, but particularly of the parts, which have habitually acted together; as when one arm is paralytic the other is liable to more frequent or almost continual motion; and when one eye becomes blind the other frequently becomes stronger; which is well known to farriers, who are said sometimes to destroy the sight of one eye to strengthen that of the other in diseased horses. Hence there is sometimes a direct sympathy, and sometimes a reverse one succeeds the torpor occasioned by defect of stimulus, the latter of which is perhaps owing to a certain time being required for the production of an accumulation of the sensorial power of irritation by the nervous branches of the torpid organ; which accumulation is now in part or entirely derived to the next link of the association. Thus in going into a coldish bath, as into a river in the summer months, we at first experience a difficulty of breathing from the torpid action of the pulmonary capillaries, owing to the deficient excitement of the sensorial power of association in consequence of the torpor of the cutaneous capillaries. But in a very short time, as in one minute, the sensorial power of irritation becomes accumulated by the inactivity of the cutaneous capillaries; and as its superabundance becomes now expended on the pulmonary capillaries, the difficult respiration ceases; though the cutaneous capillaries continue torpid by their contact with the cold water, and consequently the sensorial power of association, which used to contribute to actuate the pulmonary capillaries, is less excited. 8. In like manner when there exists an accumulation of the sensorial power of association, owing to defect of its excitement by some previous irritative or associate motions, it is generally accompanied for a certain time by a torpor not only of the link first affected, but of the subsequent parts, or of the whole train of associated motions, as in the cold fits of intermittent fevers. Yet after a time an increased action of the next links of associated motions succeeds the torpor of the first, as the absorbent vessels of the lungs act more violently in consequence of the deficient action of those of the stomach; and the skin at the commencement of sickness is pale and cold, but in a little time becomes flushed and warm. Thus we see in associate motions, which are rendered torpid by defect of excitement, that sometimes a direct, and sometimes a reverse sympathy succeeds in the subsequent links of the chain. But I believe where a torpor of irritative or of the associate motions is caused by a previous too great expenditure or exhaustion of the sensorial powers of irritation or association, no increase of action in the subsequent link ever occurs, or not till after a very long time. Thus when the stomach becomes torpid by previous violent exertion, and consequent exhaustion of the sensorial power of irritation, as after intoxication with wine or opium, or after the exhibition of some violent emetic drug, the torpor is communicated to the heart and arteries, as in continued fevers with weak pulse. But where the torpor of the stomach is produced from defective association, as in sea-sickness; or in the sickness which occurs, when a stone stimulates the ureter; no torpor is then communicated to the heart and arteries. For in the former case there is no accumulation of sensorial power in the stomach, which was previously exhausted by too great stimulus; but in the latter case the accumulation of sensorial power in the stomach during its torpor is evinced by this circumstance; that in sea-sickness the patients eat and drink voraciously at intervals; and the pulse is generally not affected by the sickness occasioned by a stone in the ureter. For the action of the stomach is then lessened, and in consequence becomes retrograde, not owing to the exhaustion of the sensorial power of irritation, but to the want of excitement of the sensorial power of association; which is caused by the defective action of the ureter, which becomes occasionally torpid by the great stimulus of the stone it contains; or which is caused by the great exhaustion of sensorial power by the pain; which affects the ureter without exciting inflammation, or increased action of it. 9. Thus though the stomach after the great stimulus of intoxication from excess of wine or opium will continue many hours without accumulation of sensorial power, as appears from the patient's experiencing no appetite at the intervals of sickness; yet after long abstinence from food, at length not only the exhausted quantity of sensorial power is renewed, but an accumulation of it at length occurs, and hunger returns. In this situation the stomach is generally about a whole day before it regains its usual powers of digestion; but if it has been still more violently stimulated, and its actions further impaired, a still more permanent torpor along with a continued fever with weak pulse is liable to occur; and a fourth part, or a half, or three fourths, or a whole lunar period passes, before it recovers its due irritability and consequent action. In similar manner, after a person has been confined in a very warm room for some hours, the cutaneous capillaries, with their secretory and absorbent vessels, become exhausted of their sensorial power of irritation by the too great violent exertions occasioned by the unusual stimulus of heat; and in coming into a colder atmosphere an inactivity of the cutaneous vessels exists at first for some time without accumulation of sensorial power; as is shewn by the continuance of the pain of cold and the paleness; but after a time both the pain of cold and paleness vanish, which now indicates an accumulation of the sensorial power of irritation, as less degrees of heat stimulate the system into due action. In the same manner, after any one has been some time in the summer sunshine, on coming into a dark cell he continues much longer before he can clearly distinguish objects, than if his eyes had only been previously exposed to the light of a cloudy day in winter; because the sensorial power of irritation, and consequent sensation, had in the first case been previously much expended or exhausted; and therefore required a much longer time before it could be produced in the brain, or derived to the optic nerves, in such quantity as to restore the deficiency, and to cause an accumulation of it; whereas in the latter case no deficiency had occurred. 10. Thus the accumulation or deficiency of sensorial power in a torpid organ, which had previously been accustomed to perpetual action, depends on the manner in which it becomes torpid; that is, whether by great previous stimulus, or great previous excitement of the power of association; or by defect of its accustomed stimulus, or of its accustomed excitement of the power of association. In the former case the sensorial power is in an exhausted state, and therefore is not likely to become so soon accumulated, as after drunkenness, or exposure to great heat, or to great light; in the latter a great accumulation of sensorial power occurs, as after exposure to cold, or hunger, or darkness. Hence when the stomach continues torpid by previous violent stimulus, as in the exhibition of digitalis, no accumulation of sensorial power of irritation supervenes; and in consequence the motions of the heart and arteries, which are associated with those of the stomach, become weak, and slow, and intermittent, from the defect of the excitement of the sensorial power of association. But what follows? as the actions of the heart and arteries are lessened by the deficient action of the sensorial power of association, and not by previous increased excitement of it; a great accumulation of the sensorial power of association occurs, which is exerted on the pulmonary and cutaneous absorbents by reverse sympathy, and produces a great absorption of the fluid effused into the cellular membrane in anasarca, with dry skin; constituting one kind of atrophy. But if at the same time the secerning vessels of the stomach are stimulated into so violent activity as to induce great consequent torpor, as probably happens when contagious matter is swallowed into the stomach with our saliva, those of the heart and arteries act feebly from the deficient excitement of the power of association; and then the cutaneous and pulmonary secerning vessels act with greater force than natural, owing to the accumulation of the sensorial power of association; and unnatural heat of the skin, and of the breath succeed; but without frequency of pulse, constituting the paresis irritativa of Class I. 2. 1. 2. And lastly, if a paucity of blood attends this paresis, or some other cause inducing a frequency of pulse, the febris inirritativa, or fever with weak pulse, is produced. But on the contrary when the stomach has previously been rendered torpid by defect of stimulus, as by hunger, if food be too hastily supplied, not only great exertion of the stomach itself succeeds, but fever with strong pulse is induced in consequence; that is, the heart and arteries are excited into more energetic action by the excess of the power of association, which catenates their motions with those of the stomach. For the redundancy of sensorial power of irritation, which was accumulated during the inactivity of the stomach, and is now called into action by stimulus, actuates that organ with increased energy, and excites by these increased motions the sensorial power of association; which has also been accumulated during the inactivity of the heart and arteries; and thus these organs also are now excited into greater action. So after the skin has been exposed some hours to greater heat than natural in the warm room, other parts, as the membranes of the nostrils, or of the lungs, or of the stomach, are liable to become torpid from direct sympathy with it, when we come into air of a moderate temperature; whence catarrhs, coughs, and fevers. But if this torpor be occasioned by defect of stimulus, as after being exposed to frosty air, the accumulation of sensorial power is exerted, and a glow of the skin follows, with increased digestion, full respiration, and more vigorous circulation. 11. It may be asked, Why is there a great and constant accumulation of the sensorial power of association, owing to the torpor of the stomach and heart and arteries, in continued fever with weak pulse; which is exerted on the cutaneous and pulmonary capillaries, so as to excite them into increased action for many weeks, and yet no such exuberance of sensorial power produces fever in winter-sleeping animals, or in chlorosis, or apepsia, or hysteria? In winter-sleeping animals I suppose the whole nervous system is torpid, or paralysed, as in the sleep of frozen people; and that the stomach is torpid in consequence of the inactivity or quiescence of the brain; and that all other parts of the body, and the cutaneous capillaries with the rest, labour under a similar torpor. In chlorosis, I imagine, the actions of the heart and arteries, as well as those of the cutaneous and pulmonary capillaries, suffer along with those of the stomach from the deficient stimulus of the pale blood; and that though the liver is probably the seat of the original torpor in this disease, with which all other parts sympathize from defect of the excitation of the sensorial power of association; yet as this torpor occurs in so small a degree as not to excite a shuddering or cold fit, no observable consequences are in general occasioned by the consequent accumulation of sensorial power. Sometimes indeed in chlorosis there does occur a frequent pulse and hot skin; in which circumstances I suppose the heart and arteries are become in some degree torpid by direct sympathy with the torpid liver; and that hence not only the pulse becomes frequent, but the capillaries of the skin act more violently by reverse sympathy with the heart and arteries, owing to the accumulation of the sensorial power of association in them during their torpid state, as occurs in irritative fever. See Article 11 of this Supplement. In apepsia chronica the actions of the stomach are not so far impaired or destroyed as totally to prevent the excitation of the sensorial power of association, which therefore contributes something towards the actions of the heart and arteries, though less than natural, as a weak pulse always I believe attends this disease. There is a torpor of the stomach, and of the upper part of the alimentary canal in hysteria, as is evident from the retrograde actions of the duodenum, stomach, and oesophagus, which constitute the globus hystericus, or sensation of a globe rising into the throat. But as these retrograde actions are less than those, which induce sickness or vomiting, and are not occasioned by previous exhaustion of the sensorial power of irritation, they do not so totally prevent the excitement of the sensorial power of association, as to lessen the motion of the heart and arteries so much as to induce fever; yet in this case, as in apepsia, and in chlorosis, the pulsations of the heart and arteries are weaker than natural, and are sometimes attended with occasionally increased action of the capillaries; as appears from the flushings of the face, and hot skin, which generally form an evening febricula in diseases attended with weak digestion. 12. The increased action, or orgasm, of the cutaneous, pulmonary, and cellular capillaries, with their secerning and absorbent vessels, in those fevers which are attended with deficiency of vital action, exhausts the patient both by the additional expenditure of sensorial power on those organs of secretion, and by the too great absorption of the mucus and fat of the body; whence great debility and great emaciation. Hence one great indication of cure of continued fever with arterial debility is to diminish the too great action of the capillaries; which is to be done by frequent ablutions, or bathing the whole skin in tepid or in cold water, as recommended by Dr. Currie of Liverpool (Philos. Trans. for 1792), for half an hour, twice a day, or at those times when the skin feels dryest and hottest. Much cool air should also be admitted, when the breath of the patient feels hot to one's hand; or when the tongue, especially its middle part, is dry, and covered with a crust of indurated mucus; as these indicate the increased action of the pulmonary capillaries; in the same manner as the dry and hot skin indicates the orgasm of the cutaneous capillaries; and the emaciation of the body that of the cellular ones. For this purpose of abating the action of the capillaries by frequent ablution or fomentation, water of any degree of heat beneath that of the body will be of service, and ought in accurate language to be called a cold bath; but the degree of coldness, where the patient is sensible, should in some measure be governed by his sensations; as it is probable, that the degree of coldness, which is most grateful to him, will also be of the greatest benefit to him. See Class III. 2. 1. 12. and Article 15 of this Supplement. Another great use of frequent ablutions, or fomentations, or baths, in fevers, where the stomach is in some degree torpid, is to supply the system with aqueous fluid by means of the cutaneous absorbents; which is dissipated faster by the increased action of the secerning capillaries, than the stomach can furnish, and occasions great thirst at the intervals of the sickness. IX. _Torpor of the Lungs._ 1. The lungs in many cases of contagion may first be affected with torpor, and the skin become cold by sympathy; in the same manner as a cold skin on going into the cold bath induces difficulty of breathing. Or the stomach may become affected with torpor by its sympathy with the lungs, as in the experiments of Mr. Watt with hydro-carbonate gas; a few respirations of which induced sickness, and even syncope. When the stomach or skin is thus affected secondarily by association, an accumulation of sensorial power occurs much sooner, than when these parts become torpid in consequence of previous excess of stimulus; and hence they sooner recover their accustomed action, and the fever ceases. The particles of contagious matter thus received by respiration somewhat resemble in their effects the acid gases from burning sulphur, or from charcoal; which, if they do not instantly destroy, induce a fever, and the patient slowly recovers. 2. I was some years ago stooping down to look, which way the water oozed from a morass, as a labourer opened it with a spade, to detect the source of the spring, and inhaled a vapour, which occasioned an instant sense of suffocation. Immediately recoiling I believe I inhaled it but once; yet a few hours afterwards in the cool of the evening, when I returned home rather fatigued and hungry, a shivering and cold fit occurred, which was followed by a hot one; and the whole disease began and terminated in about twelve hours without return. In this case the power of fear, or of imagination, was not concerned; as I neither thought of the bad air of a morass before I perceived it; nor expected a fever-fit, till it occurred. In this case the torpor commenced in the lungs, and after a few hours, by the addition of fatigue, and cold, and hunger, was propagated by direct sympathy to the rest of the system. An orgasm or increased action of the whole system was then induced by the accumulation of sensorial power of irritation in the lungs, and of association in the other organs; and when these subsided, the disease ceased. It may be asked, could a torpor of the capillaries of the air-vessels of the lungs be so suddenly produced by great stimulation?--It appears probable, that it might, because great exertion of irritative motions may be instantly produced without our perceiving them; that is, without their being attended by sensation, both in the lungs and stomach; and the organs may become torpid by the great expenditure of the sensorial power of irritation in an instant of time; as paralysis frequently instantly follows too great an exertion of voluntary power. 3. When the capillaries of the lungs act too violently, as in some continued fevers; which is known by the heat of the breath, and by the dryness of the tongue, especially of the middle part of it; not only cooler air might be admitted more freely into a sick room to counteract this orgasm of the pulmonary capillaries; but perhaps the patient might breathe with advantage a mixture of carbonic acid gas, or of hydrogene gas, or of azote with atmospheric air. And on the contrary, when there exists an evident torpor of the pulmonary capillaries, which may be known by the correspondent chilness of the skin; and by a tickling cough, which sometimes attends cold paroxysms of fever, and is then owing to the deficient absorption of the pulmonary mucus, the saline parts of which stimulate the bronchiæ, or air-vessels; a mixture of one part of oxygen gas with 10 or 20 parts of atmospheric air might probably be breathed with great advantage. X. _Torpor of the Brain._ As the inactivity or torpor of the absorbent vessels of the brain is the cause of hydrocephalus internus; and as the deficiency of venous absorption in the brain, or torpor of the extremities of its veins, is believed frequently to be the cause of apoplexies; so there is reason to conclude, that the torpor of the secerning vessels of the brain, which are supposed to produce the sensorial power, may constitute the immediate cause of some fevers with arterial debility. And also that the increased action of these secerning vessels may sometimes constitute the immediate cause of fevers with arterial strength. It is nevertheless probable, that the torpor or orgasm of the sanguiferous, absorbent, or secerning vessels of the brain may frequently exist as a secondary effect, owing to their association with other organs, as the stomach or lungs; and may thus be produced like the torpor of the heart and arteries in inirritative fevers, or like the orgasm of those organs in irritative fevers, or inflammatory ones. Where there exists a torpor of the brain, might not very slight electric shocks passed frequently through it in all directions be used with advantage? Might not fomentations of 94 or 96 degrees of heat on the head for an hour at a time, and frequently repeated, stimulate the brain into action; as in the revival of winter-sleeping animals by warmth? Ether externally might be frequently applied, and a blister on the shaved head. Where the secerning vessels of the brain act with too great energy, as in some inflammatory fevers, might it not be diminished by laying the patient horizontally on a mill-stone, and whirling him, till sleep should be produced, as the brain becomes compressed by the centrifugal force? See Article 15 of this Supplement. XI. _Torpor of the Heart and Arteries._ 1. It was shewn in Class IV. 1. 1. 6. in IV. 2. 1. 2. and in Suppl. I. 6. 3. that a reverse sympathy generally exists between the lacteal and lymphatic branches of the absorbent system. Hence, when the motions of the absorbents of the stomach are rendered torpid or retrograde in fevers with arterial debility, those of the skin, lungs, and cellular membrane, act with increased energy. But the actions of the muscular fibres of the heart and arteries are at the same time associated with those of the muscular fibres of the stomach by direct sympathy. Both these actions occur during the operation of powerful emetics, as squill, or digitalis; while the motions of the stomach continue torpid or retrograde, the cellular and cutaneous absorbents act with greater energy, and the pulsations of the heart and arteries become weaker, and sometimes slower. 2. The increased action of the stomach after a meal, and of the heart and arteries at the same time from the stimulus of the new supply of chyle, seems originally to have produced, and to have established, this direct sympathy between them. As the increased action of the absorbents of the stomach after a meal has been usually attended with diminished action of the other branches of the absorbent system, as mentioned in Class IV. 1. 1. 6. and has thus established a reverse sympathy between them. 2. Besides the reverse sympathy of the absorbent vessels and the muscles of the stomach, and of the heart and arteries, with those of the skin, lungs, and cellular membrane; there exists a similar reverse sympathy between the secerning vessels or glands of the former of these organs with those of the latter; that is the mucous glands of the heart and arteries act generally by direct sympathy with those of the stomach; and the mucous glands of the cellular membrane of the lungs, and of the skin, act by reverse sympathy with them both. Hence when the stomach is torpid, as in sickness, this torpor sometimes only affects the absorbent vessels of it; and then the absorbents of the cellular membrane and the skin only act with increased energy by reverse sympathy. If the torpor affects the muscular fibres of the stomach, those of the heart and arteries act by direct sympathy with it, and a weak pulse is produced, as in the exhibition of digitalis, but without increase of heat. But if the torpor also affects the glands of the stomach, the cutaneous and pulmonary glands act with greater energy by their reverse sympathy with those of the stomach, and of the heart and arteries; and great heat is produced along with increased perspiration both from the skin and lungs. 3. There is some difficulty in explaining, why the actions of the extensive system of capillary glands, which exist on every other membrane and cell in the body for the purpose of secreting mucus and perspirable matter, should so generally act by reverse sympathy with those of the stomach and upper part of the intestines. It was shewn in Class IV. 1. 1. 6. that when the stomach was filled with solid and fluid aliment, the absorbents of the cellular membrane, and of the bladder, and of the skin acted with less energy; as the fluids they were used to absorb and transmit into the circulation, were now less wanted; and that hence by habit a reverse sympathy obtained between these branches of the absorbents of the alimentary canal, and those of the other parts of the body. Now, as at this time less fluid was absorbed by the cutaneous and cellular lymphatics, it would happen, that less would be secreted by their correspondent secerning vessels, or capillary glands; and that hence by habit, these secerning vessels would acquire a reverse sympathy of action with the secerning vessels of the alimentary canal. Thus when the absorption of the tears by the puncta lacrymalia is much increased by the stimulus of snuff; or of an affecting idea, on the nasal dusts, as explained in Sect. XVI. 8. 2. a great increase of the secretion of tears from the lacrymal glands is produced by the direct sympathy of the action of these glands with those of their correspondent absorbents; and that though in this case they are placed at so great a distance from each other. 4. A difficult question here occurs; why does it happen, that in fevers with weak pulse the contractions of the heart and arteries become at the same time more frequent; which also sometimes occurs in chlorosis, and in some hysteric and hypochondriac diseases, and in some insanities; yet at other times the weak pulse becomes at the same time slow, as in the exhibition of digitalis, and in paresis irritativa, described in Class I. 2. 1. 2. which may be termed a fever with slow pulse? this frequency of pulse can not depend on heat, because it sometimes exists without heat, as towards the end of some fevers with debility. Now as apoplexies, which are sometimes ascribed to fulness of blood, are attended with slow pulse; and as in animals dying in the slaughter house from deficiency of blood the pulse becomes frequent in extreme; may not the frequency of pulse in fevers with arterial debility be in general owing to paucity of blood? as explained in Sect. XXXII. 2. 3. and its slowness in paresis irritativa be caused by the debility being accompanied with due quantity of blood? or may not the former circumstance sometimes depend on a concomitant affection of the brain approaching to sleep? or to the unusual facility of the passage of the blood through the pulmonary and aortal capillaries? in which circumstance the heart may completely empty itself at each pulsation, though its contractions may be weak. While the latter depends on the difficulty of the passage of the blood through the pulmonary or aortal capillaries, as in the cold fits of intermittents, and in some palpitations of the heart, and in some kinds of hæmoptoe? in these cases the increased resistance prevents the heart from emptying itself, and in consequence a new diastole sooner occurs, and thus the number of pulsations becomes greater in a given time. 5. In respect to the sympathies of action, which produce or constitute fever with debility, the system may be divided into certain provinces, which are assentient or opposite to each other. First, the lacteals or absorbent vessels of the stomach, and upper part of the intestines; secondly, the lymphatics or all the other branches of the absorbent vessels, which arise from the skin, mucous membranes, cellular membranes, and the various glands. These two divisions act by reverse sympathy with each other in the hot fits of fever with debility, though by direct sympathy in the cold ones. The third division consists of the secerning vessels of the stomach and upper intestines; and the fourth of the secerning vessels of all the other parts of the body, as the capillary glands of the skin, lungs, and cellular membrane, and the various other glands belonging to the sanguiferous system. Many of these frequently, but the capillaries always, act by reverse sympathy with those of the third division above mentioned in the hot fits of fever with debility, though by direct sympathy with them in the cold fits. Fifthly, the muscular fibres of the stomach, and upper intestines; and sixthly, the muscular fibres of the heart and arteries. The actions of these two last divisions of moving fibres act by direct sympathy with each other, both in the cold and hot fits of fevers with debility. The efficient cause of those apparent sympathies in fevers with weak pulse may be thus understood. In the cold paroxysm of fever with weak pulse the part first affected I believe to be the stomach, and that it has become torpid by previous violent exertion, as by swallowing contagious matter mixed with saliva, and not by defect of stimulus, as from cold or hunger. The actions of this important organ, which sympathizes with almost every part of the body, being thus much diminished or nearly destroyed, the sensorial power of association is not excited; which in health contributes to move the heart and arteries, and all the rest of the system; whence an universal torpor occurs. When the hot fit approaches, the stomach in fevers with strong pulse regains its activity by the accumulation of the sensorial power of either irritation, if it was the part first affected, or of association if it was affected in sympathy with some other torpid part, as the spleen or liver; which accumulation is produced during its torpor. At the same time all the other parts of the system acquire greater energy of action by the accumulation of the sensorial power of association, which was produced, during their inactivity in the cold fit. But in fevers with weak pulse the stomach, whose sensorial power of irritation had been previously exhausted by violent action, acquires no such quick accumulation of sensorial power, but remains in a state of torpor after the hot fit commences. The heart and arteries remain also in a state of torpor, because there continues to be no excitement of their power of association owing to the torpid motions of the stomach; but hence it happens, that there exists at this time a great accumulation of the power of association in the less active fibres of the heart and arteries; which, as it is not excited and expended by them, increases the associability of the next link of the associated chain of motions, which consists of the capillaries or other glands; and that in so great a degree as to actuate them with unnatural energy, and thus to produce a perpetual hot fit of fever. Because the associability of the capillaries is so much increased by the accumulation of this power, owing to the lessened activity of the heart and arteries, as to over-balance the lessened excitement of it by the weaker movements of the heart and arteries. 6. When the accumulation of the sensorial power of irritation caused by defect of stimulus is greater in the first link of a train of actions, to which associated motions are catenated, than the deficiency of the excitement of the sensorial power of association in the next link, what happens?--the superabundance of the unemployed sensorial power of the first link is derived to the second; the associability of which thus becomes so greatly increased, that it acts more violently than natural, though the excitement of its power of association by the lessened action of the first link is less than natural. So that in this situation the withdrawing of an accustomed stimulus in some parts of the system will decrease the irritative motions of that part, and at the same time occasion an increase of the associate motion of another part, which is catenated with it. This circumstance nevertheless can only occur in those parts of the system, whose natural actions are perpetual, and the accumulation of sensorial power on that account very great, when their activity is much lessened by the deduction of their usual stimulus; and are therefore only to be found in the sanguiferous system, or in the alimentary canal, or in the glands and capillaries. Of the first of which the following is an instance. The respiration of a reduced atmosphere, that is of air mixed with hydrogene or azote, quickens the pulse, as observed in the case of Mrs. Eaton by Dr. Reynolds and Dr. Thornton; to which Dr. Beddoes adds in a note, that "he never saw an instance in which a lowered atmosphere did not at the moment quicken the pulse, while it weakened the action of the heart and arteries." Considerations on Factitious Airs, by Thomas Beddoes and James Watt, Part III. p. 67. Johnson, London. By the assistance of this new fact the curious circumstance of the quick production of warmth of the skin on covering the head under the bed-clothes, which every one must at some time have experienced, receives a more satisfactory explanation, than that which is given in Class IV. 1. 1. 2. which was printed before this part of Dr. Beddoes's Considerations was published. For if the blood be deprived of its accustomed quantity of oxygen, as in covering the head in bed, and thus breathing an air rendered impure by repeated respiration, or by breathing a factitious air with less proportion of oxygen, which in common respiration passes through the moist membranes of the lungs, and mixes with the blood, the pulsations of the heart and arteries become weaker, and consequently quicker, by the defect of the stimulus of oxygen. And as these vessels are subject to perpetual motion, the accumulation of the sensorial power of irritation becomes so great by their lessened activity, that it excites the vessels next connected, the cutaneous capillaries for instance, into more energetic actions, so as to produce increased heat of the skin, and greater perspiration. How exactly this resembles a continued fever with weak and quick pulse!--in the latter the action of the heart and arteries are lessened by defect of the excitement of the sensorial power of association, owing to the torpor or lessened actions of the stomach; hence the accumulation of the sensorial power of association in this case, as the accumulation of that of irritation in the former, becomes so abundant as to excite into increased action the parts most nearly connected, as the cutaneous capillaries. In respect to the circumstance mentioned by Sydenham, that covering the head in bed in a short time relieved the pertinacious sickness of the patient, it must be observed, that when the action of the heart and arteries become weakened by the want of the due stimulus of the proper quantity of oxygen in the blood, that an accumulation of the sensorial power of irritation occurs in the fibres of the heart and arteries, which then is expended on those of the capillary glands, increasing their actions and consequent secretions and heat. And then the stomach is thrown into stronger action, both by the greater excitement of its natural quantity of the sensorial power of association by the increased actions of the capillaries, and also by some increase of associability, as it had been previously a long time in a state of torpor, or less activity than natural, as evinced by its perpetual sickness. In a manner somewhat similar to this, is the redness of the skin produced in angry people by the superabundance of the unemployed sensorial power of volition, as explained in Class IV. 2. 3. 5. Rubor ex irâ. From hence we learn how, when people in fevers with weak pulse, or in dropsies, become insane, the abundance of the unemployed sensorial power of volition increases the actions of the whole moving system, and cures those diseases. 7. As the orgasm of the capillaries in fevers with weak pulse is immediately caused by the torpid actions of the heart and arteries, as above explained, this supplies us with another indication of cure in such fevers, and that is to stimulate these organs. This may probably be done by some kind of medicines, which are known to pass into the blood unchanged in some of their properties. It is possible that nitre, or its acid, may pass into the blood and increase the colour of it, and thus increase its stimulus, and the same may be supposed of other salts, neutral or metallic? As rubia tinctoria, madder, colours the bones of young animals, it must pass into the blood with its colouring matter at least unchanged, and perhaps many other medicines may likewise affect the blood, and thus act by stimulating the heart and arteries, as well as by stimulating the stomach; which circumstance deserves further attention. Another way of immediately stimulating the heart and arteries would be by transfusing new blood into them. Is it possible that any other fluid besides blood, as chyle, or milk, or water, could, if managed with great art, be introduced safely or advantageously into the vein of a living animal? A third method of exciting the heart and arteries immediately is by increasing the natural stimulus of the blood, and is well worthy experiment in all fevers with weak pulse; and that consists in supplying the blood with a greater proportion of oxygen; which may be done by respiration, if the patient was to breathe either oxygen gas pure, or diluted with atmospheric air, which might be given to many gallons frequently in a day, and by passing through the moist membranes of the lungs, according to the experiments of Dr. Priestley, and uniting with the blood, might render it more stimulant, and thus excite the heart and arteries into greater action! May not some easier method of exhibiting oxygen gas by respiration be discovered, as by using very small quantities of hyper-oxygenated marine acid gas very much diluted with atmospheric air? XII. _Torpor of the Stomach and upper Intestines._ 1. The principal circumstance, which supports the increased action of the capillaries in continued fever with weak pulse, is their reverse sympathy with those of the stomach and upper intestines, or with those of the heart and arteries. The torpor of the stomach and upper intestines is apparent in continued fevers from the total want of appetite for solid food, besides the sickness with which fevers generally commence, and the frequent diarrhoea with indigested stools, at the same time the thirst of the patient is sometimes urgent at the intervals of the sickness. Why the stomach can at this time take fluids by intervals, and not solids, is difficult to explain; except it be supposed, as some have affirmed, that the lacteal absorbents are a different branch from the lymphatic absorbents, and that in this case the former only are in a state of permanent torpor. 2. The torpor of the heart and arteries is known by the weakness of the pulse. When the actions of the absorbents of the stomach are diminished by the exhibition of small doses of digitalis, or become retrograde by larger ones, the heart and arteries act more feebly by direct sympathy; but the cellular, cutaneous, and pulmonary absorbents are excited into greater action. Whence in anasarca the fluids in the cellular membrane throughout the whole body are absorbed during the sickness, and frequently a great quantity of atmospheric moisture at the same time; as appears by the very great discharge of urine, which sometimes happens in these cases; and in ileus the prodigious evacuations by vomiting, which are often a hundred fold greater than the quantity swallowed, evince the great action of all the other absorbents during the sickness of the stomach. 3. But when the stomach is rendered permanently sick by an emetic drug, as by digitalis, it is not probable, that much accumulation of sensorial power is soon produced in this organ; because its usual quantity of sensorial power is previously exhausted by the great stimulus of the foxglove; and hence it seems probable, that the great accumulation of sensorial power, which now causes the increased action of the absorbents, is produced in consequence of the inactivity of the heart and arteries; which inactivity is induced by deficient excitement of the sensorial power of association between those organs and the stomach, and not by any previous exhaustion of their natural quantity of sensorial power; whereas in ileus, where the torpor of the stomach, and consequent sickness, is induced by reverse sympathy with an inflamed intestine, that is, by dissevered or defective association; the accumulation of sensorial power, which in that disease so violently actuates the cellular, pulmonary, and cutaneous absorbents, is apparently produced by the torpor of the stomach and lacteals, and the consequent accumulation of the sensorial power of association in them owing to their lessened action in sickness. 4. This accounts for the dry skin in fevers with weak pulse, where the stomach and the heart and arteries are in a torpid state, and for the sudden emaciation of the body; because the actions of the cellular and cutaneous absorbents are increased by reverse sympathy with those of the stomach, or with those of the heart and arteries; that is by the expenditure of that sensorial power of association, which is accumulated in consequence of the torpor of the stomach and heart and arteries, or of either of them; this also explains the sudden absorption of the milk in puerperal fevers; and contributes along with the heat of the respired air to the dryness of the mucous membrane of the tongue and nostrils. 5. Besides the reverse sympathy, with which the absorbent vessels of the stomach and upper intestines act in respect to all the other absorbent vessels, as in the exhibition of digitalis, and in ileus; there is another reverse sympathy exists between the capillaries, or secretory vessels of the stomach, and those of the skin. Which may nevertheless be occasioned by the accumulation of sensorial power by the torpor of the heart and arteries, which is induced by direct sympathy with the stomach; thus when the torpor of the stomach remains in a fever-fit which might otherwise have intermitted, the torpor of the heart and arteries remains also by direct sympathy, and the increased cutaneous capillary action, and consequent heat, are produced by reverse sympathy; and the fever is thus rendered continual, owing primarily to the torpor of the stomach. 6. The reverse sympathy, which exists between the capillaries of the stomach and the cutaneous capillaries, appears by the chillness of some people after dinner; and contrary-wise by the digestion being strengthened, when the skin is exposed to cold air for a short time; as mentioned in Class IV. 1. 1. 4. and IV. 2. 1. 1. and from the heat and glow on the skin, which attends the action of vomiting; for though when sickness first commences, the skin is pale and cold; as it then partakes of the general torpor, which induces the sickness; yet after the vomiting has continued some minutes, so that an accumulation of sensorial power exists in the capillaries of the stomach, and of the skin, owing to their diminished action; a glow of the skin succeeds, with sweat, as well as with increased absorption. 7. Nevertheless in some circumstances the stomach and the heart and arteries seem to act by direct sympathy with the cutaneous capillaries, as in the flushing of the face and glow of the skin of some people after dinner; and as in fevers with strong pulse. In these cases there appears to be an increased production of sensorial power, either of sensation, as in the blush of shame; or of volition, as in the blush of anger; or of irritation, as in the flushed face after dinner above mentioned. This increased action of the capillaries of the skin along with the increased actions of the stomach and heart is perhaps to be esteemed a synchronous increase of action, rather than a sympathy between those organs. Thus the flushing of the face after dinner may be owing to the secretion of sensorial power in the brain being increased by the association of that organ with the stomach, in a greater proportion than the increased expenditure of it, or may be owing also to the stimulus of new chyle received into the blood. 8. When the stomach and the heart and arteries are rendered torpid in fevers, not only the cutaneous, cellular, and pulmonary absorbents are excited to act with greater energy; but also their correspondent capillaries and secerning vessels or glands, especially perhaps those of the skin, are induced into more energetic action. Whence greater heat, a greater secretion of perspirable matter, and of mucus; and a greater absorption of them both, and of aerial moisture. These reverse sympathies coincide with other animal facts, as in eruption of small pox on the face and neck the feet become cold, while the face and neck are much flushed; and in the hemiplagia, when one arm and leg become disobedient to volition, the patient is perpetually moving the other. Which are well accounted for by the accumulation of sensorial power in one part of an associated series of actions, when less of it is expended by another part of it; and by a deficiency of sensorial power in the second link of association, when too much of it is expended by the first. 9. This doctrine of reverse sympathy enables us to account for that difficult problem, why in continued fevers the increased action of the cutaneous, cellular, and pulmonary capillaries proceeds without interruption or return of cold fit; though perhaps with some exacerbations and remissions; and that during a quarter, or half, or three quarters, or a whole lunation; while at the same time the pulsations of the heart and arteries are weaker than natural. To this should be added the direct sympathy, which exists between the peristaltic motions of the fibres of the stomach, and the pulsations of the heart. And that the stomach has become torpid by the too great stimulus of some poisonous or contagious matter; and this very intricate idea of continued fever with feeble pulse is reduced to curious simplicity. The direct sympathy of the stomach and heart and arteries not only appears from the stronger and slower pulse of persons exhausted by fatigue, after they have drank a glass of wine, and eaten a few mouthfuls; but appears also from the exhibition of large doses of digitalis; when the patient labours under great and incessant efforts to vomit, at the same time that the actions of the absorbent system are known to be much increased by the hasty absorption of the serous fluid in anasarca, the pulsations of the heart become slow and intermittent to an alarming degree. See Class IV. 2. 1. 17. and 18. 10. It would assist us much in the knowledge and cure of fevers, if we could always determine, which part of the system was primarily affected; and whether the torpor of it was from previous excess or defect of stimulus; which the industry of future observers must discover. Thus if the stomach be affected primarily, and that by previous excess of stimulus, as when certain quantities of opium, or wine, or blue vitriol, or arsenic, are swallowed, it is some time in recovering the quantity of sensorial power previously exhausted by excess of stimulus, before any accumulation of it can occur. But if it be affected with torpor secondarily, by sympathy with some distant part; as with the torpid capillaries of the skin, that is by defective excitement of the sensorial power of association; or if it be affected by defect of stimulus of food or of heat; it sooner acquires so much accumulation of sensorial power, as to be enabled to accommodate itself to its lessened stimulus by increase of its irritability. Thus in the hemicrania the torpor generally commences in a diseased tooth, and the membranes about the temple, and also those of the stomach become torpid by direct synchronous sympathy; and pain of the head, and sickness supervene; but no fever or quickness of pulse. In this case the torpor of the stomach is owing to defect of the sensorial power of association, which is caused by the too feeble actions of the membranes surrounding the diseased tooth, and thus the train of sympathy ceases here without affecting the motions of the heart and arteries; but where contagious matter is swallowed into the stomach, the stomach after a time becomes torpid from exhaustion of the sensorial power of irritation, and the heart and arteries act feebly from defect of the excitement of the power of association. In the former case the torpor of the stomach is conquered by accumulation of the power of association in one or two whole days; in the latter it recovers by accumulation of the power of irritation in three or four weeks. In intermittent fevers the stomach is generally I believe affected secondarily by sympathy with the torpid cutaneous capillaries, or with some internal torpid viscus, and on this account an accumulation of sensorial power arises in a few hours sufficient to restore the natural irritability of this organ; and hence the hot fit succeeds, and the fever intermits. Or if this accumulation of sensorial power becomes excessive and permanent, the continued fever with strong pulse is produced, or febris irritativa. In continued fevers the stomach is frequently I suppose affected with torpor by previous excess of stimulus, and consequent exhaustion of sensorial power, as when contagious matter is swallowed with the saliva, and it is then much slower in producing an accumulation of sensorial power sufficient to restore its healthy irritability; which is a frequent cause of continued fever with weak pulse or febris inirritativa. Which consists, after the cold fit is over, in a more frequent and more feeble action of the heart and arteries, owing to their direct sympathy with the muscular fibres of the torpid stomach; together with an increased action of the capillaries, glands, and absorbents of the skin, and cellular membrane, owing to their reverse sympathy with the torpid capillaries, glands, and absorbents of the stomach, or with those of the heart and arteries. Or in more accurate language. 1. The febris inirritativa, or fever with weak pulse, commences with torpor of the stomach, occasioned by previous exhaustion of sensorial power of irritation by the stimulus of contagious matter swallowed with the saliva. 2. The whole system becomes torpid from defect of the excitement or the sensorial power of association owing to the too feeble actions of the stomach, this is the cold fit. 3. The whole system, except the stomach with the upper intestines, and the heart and arteries, falls into increased action, or orgasm, owing to accumulation of sensorial power of association during their previous torpor, this is the hot fit. 4. The stomach and upper intestines have not acquired their natural quantity of sensorial power of irritation, which was previously exhausted by violent action in consequence of the stimulus of contagious matter, and the heart and arteries remain torpid from deficient excitement of the sensorial power of association owing to the too feeble actions of the stomach. 5. The accumulation of sensorial power of association in consequence of the torpor of the heart and arteries occasions a perpetual orgasm, or increased action of the capillaries. 11. From hence it may be deducted first, that when the torpor of the stomach first occurs, either as a primary effect, or as a secondary link of some associate train or circle of motions, a general torpor of the system sometimes accompanies it, which constitutes the cold fit of fever; at other times no such general torpor occurs, as during the operation of a weak emetic, or during sea-sickness. Secondly. After a time it generally happens, that a torpor of the stomach ceases, and its actions are renewed with increase of vigour by accumulation of sensorial power during its quiescence; as after the operation of a weak emetic, or at the intervals of sea-sickness, or after the paroxysm of an intermittent fever. Thirdly. The stomach is sometimes much slower in recovering from a previous torpor, and is then the remote cause of continued fever with weak pulse; which is owing to a torpor of the heart and arteries, produced in consequence of the deficient excitement of the power of association by the too weak actions of the stomach; and to an orgasm of the capillaries of the other parts of the system, in consequence of the accumulation of sensorial power occasioned by the inactivity of the heart and arteries. Fourthly. The torpor of the stomach is sometimes so complete, that probably the origin of its nerves is likewise affected, and then no accumulation of sensorial power occurs. In this case the patient dies for want of nourishment; either in three or four weeks, of the inirritative fever; or without quick pulse, by what we have called paresis irritativa. Or he continues many years in a state of total debility. When this torpor suddenly commences, the patient generally suffers epileptic fits or temporary insanity from the disagreeable sensation of so great a torpor of the stomach; which also happens sometimes at the eruption of the distinct small pox; whence we have termed this disease anorexia epileptica. See Class II. 2. 2. 1. and III. 1. 1. 7. and Suppl. I. 14. 3. Fifthly. When this torpor of the stomach is less in degree or extent, and yet without recovering its natural irritability by accumulation of sensorial power, as it does after the cold fit of intermittent fever, or after the operation of mild emetics, or during syncope; a permanent defect of its activity, and of that of the upper intestines, remains, which constitutes apepsia, cardialgia, hypochondriasis, and hysteria. See Class I. 3. 1. 3. and I. 2. 4. 5. Sixthly. If the torpor of the stomach be induced by direct sympathy, as in consequence of a previous torpor of the liver, or spleen, or skin, an accumulation of sensorial power will sooner be produced in the stomach; because there has been no previous expenditure of it, the present torpor of the stomach arising from defect of association. Hence some fevers perfectly intermit, the stomach recovering its complete action after the torpor and consequent orgasm, which constitute the paroxysm of fever, are terminated. Seventhly. If the torpor of the stomach be owing to defect of irritation, as to the want of food, an accumulation of sensorial power soon occurs with an increase of digestion, if food be timely applied; or with violent inflammation, if food be given in too great quantity after very long abstinence. Eighthly. If the torpor of the stomach be induced by defect of pleasurable sensation, as when sickness is caused by the suggestion of nauseous ideas; an accumulation of sensorial power soon occurs, and the sickness ceases with the return of hunger; for in this case the inactivity of the stomach is occasioned by the subduction of agreeable sensation, which acts as a subduction of stimulus, and not by exhausting the natural quantity of sensorial power in the fibres or nerves of the stomach. Ninthly. If the torpor of the stomach be induced by a twofold cause, as in sea-sickness. See Vertigo rotatoria. Class IV. 2. 1. 10. in which the first link of association acts too strongly, and in consequence expends more than usual of the sensorial power of irritation; and secondly in which sensation is produced between the links of association, and dissevers or enfeebles them; the accumulation of sensorial power soon occurs in the stomach; as no previous expenditure of it in that organ has occurred. Whence in sea-sickness the persons take food with eagerness at times, when the vertigo eases for a few minutes. Tenthly. If the gastric torpor be induced by previous violent exertion, as after intoxication, or after contagious matter has been swallowed, or some poisons, as digitalis, or arsenic; an accumulation of sensorial power very slowly succeeds; whence long sickness, or continued fever, because the quantity of sensorial power already wasted must first be renewed, before an accumulation of it can be produced. 12. This leads us to a second indication of cure in continued fevers, which consists in strengthening the actions of the stomach; as the first indication consisted in decreasing the actions of the cutaneous capillaries and absorbents. The actions of the stomach may sometimes be increased by exhibiting a mild emetic; as an accumulation of sensorial power in the fibres of the stomach is produced during their retrograde actions. Besides the evacuation of any noxious material from the stomach and duodenum, and from the absorbents, which open their mouths on their internal surfaces, by their retrograde motion. It is probable, that when mild emetics are given, as ipecacuanha, or antimonium tartarizatum, or infusion of chamomile, they are rejected by an inverted motion of the stomach and oesophagus in consequence of disagreeable sensation, as dust is excluded from the eye; and these actions having by previous habit been found effectual, and that hence there is no exhaustion of the sensorial power of irritation. But where strong emetics are administered, as digitalis, or contagious matter, the previous exhaustion of the sensorial power of irritation seems to be a cause of the continued retrograde actions and sickness of the stomach. An emetic of the former kind may therefore strengthen the power of the stomach immediately after its operation by the accumulation of sensorial power of irritation during its action. See Class IV. 1. 1. Another method of decreasing the action of the stomach for a time, and thence of increasing it afterwards, is by the accumulation of the sensorial power of irritation during its torpor; is by giving ice, iced water, iced creams, or iced wine. This accounts for the pleasure, which many people in fevers with weak pulse express on drinking cold beverage of any kind. A second method of exciting the stomach into action, and of decreasing that of the capillaries in consequence, is by the stimulus of wine, opium, bark, metallic salts of antimony, steel, copper, arsenic, given in small repeated quantities; which so long as they render the pulse slower are certainly of service, and may be given warm or cold, as most agreeable to the patient. For it is possible, that the capillaries of the stomach may act too violently, and produce heat, at the same time that the large muscles of it may be in a torpid state; which curious circumstance future observations must determine. Thirdly. Hot fomentation on the region of the stomach might be of most essential service by its stimulus, as heat penetrates the system not by the absorbent vessels, but by external influence; whence the use of hot fomentation to the head in torpor of the brain; and the use of hot bath in cases of general debility, which has been much too frequently neglected from a popular error occasioned by the unmeaning application of the word relaxation to animal power. If the fluid of heat could be directed to pass through particular parts of the body with as little diffusion of its influence, as that of electricity in the shocks from the coated jar, it might be employed with still greater advantage. Fourthly. The use of repeated small electric shocks through the region of the stomach might be of service in fevers with weak pulse, and well deserves a trial; twenty or thirty small shocks twice a day for a week or two would be a promising experiment. Fifthly. A blister on the back, or sides, or on the pit of the stomach, repeated in succession, by stimulating the skin frequently strengthens the action of the stomach by exciting the sensorial power of association; this especially in those fevers where the skin of the extremities, as of the hands or nose or ears, sooner becomes cold, when exposed to the air, than usual. Sixthly. The action of the stomach may be increased by preventing too great expenditure of sensorial power in the link of previous motion with which it is catenated, especially if the action of that link be greater than natural. Thus as the capillaries of the skin act too violently in fevers with weak pulse, if these are exposed to cold air or cold water, the sensorial power, which previously occasioned their orgasm, becomes accumulated, and tends to increase the action of the stomach; thus in those fevers with weak pulse and hot skin, if the stomach be stimulated by repeated small doses of bark and wine or opium, and be further excited at the same time by accumulation of sensorial power occasioned by rendering the capillaries torpid by cold air or water, this twofold application is frequently attended with visible good effect. By thus stimulating the torpid stomach into greater action, the motions of the heart and arteries will likewise be increased by the greater excitement of the power of association. And the capillaries of the skin will cease to act so violently, from their not possessing so great a superfluity of sensorial power as during the greater quiescence of the stomach and of the heart and arteries. Which is in some circumstances similar to the curious phenomenon mentioned in Class IV. 2. 2. 10; where, by covering the chill feet with flannel at the eruption of the small-pox, the points of the flannel stimulate the skin of the feet into greater action, and the quantity of heat, which they possess, is also confined, or insulated, and further increases by its stimulus the activity of the cutaneous vessels of the feet; and by that circumstance abates the too great action of the capillaries of the face, and the consequent heat of it. XIII. _Case of continued fever._ The following case of continued fever which I frequently saw during its progress, as it is less complicate than usual, may illustrate this doctrine. Master S. D. an active boy about eight years of age, had been much in the snow for many days, and sat in the classical school with wet feet; he had also about a fortnight attended a writing school, where many children of the lower order were instructed. He was seized on February the 8th, 1795, with great languor, and pain in his forehead, with vomiting and perpetual sickness; his pulse weak, but not very frequent. He took an emetic, and on the next day, had a blister, which checked the sickness only for a few hours; his skin became perpetually hot, and dry; and his tongue white and furred; his pulse when asleep about 104 in a minute, and when awake about 112. Fourth day of the disease. He has had another blister, the pain of his head is gone, but the sickness continues by intervals; he refuses to take any solid food, and will drink nothing but milk, or milk and water, cold. He has two or three very liquid stools every day, which are somtimes green, but generally of a darkish yellow, with great flatulency both upwards and downwards at those times. An antimonial powder was once given, but instantly rejected; a spoonful of decoction of bark was also exhibited with the same event. His legs are bathed, and his hands and face are moistened twice a day for half an hour in warmish water, which is nevertheless much colder than his skin. Eighth day. His skin continues hot and dry without any observable remissions, with liquid stools and much flatulency and sickness; his water when observed was of a straw colour. He has asked for cyder, and drinks nearly a bottle a day mixed with cold water, and takes three drops of laudanum twice a day. Twelfth day. He continues much the same, takes no milk, drinks only cyder and water, skin hot and dry, tongue hot and furred, with liquid stools, and sickness always at the same time; sleeps much. Sixteenth day. Was apparently more torpid, and once rather delirious; pulse 112. Takes only capillaire and water; sleeps much. Twentieth day. Pulse 100, skin dry but less hot, liquid stools not so frequent, he is emaciated to a great degree, he has eaten half a tea-cup full of custard to day, drinks only capillaire and water, has thrice taken two large spoonfuls of decoction of bark with three drops of laudanum, refuses to have his legs bathed, and will now take nothing but three drops of laudanum twice a day. Twenty-fourth day. He has gradually taken more custard every day, and began to attend to some new play things, and takes wine syllabub. Twenty-eighth day. He daily grows stronger, eats eggs, and and butter, and sleeps immediately after his food, can creep on his hands and knees, but cannot stand erect. Thirty-second day. He cannot yet stand alone safely, but seems hourly to improve in strength of body, and activity of mind. In this case the remote cause of his fever could not be well ascertained, as it might be from having his feet cold for many successive days, or from contagion; but the latter seems more probable, because his younger brother became ill of a similar fever about three weeks afterwards, and probably received the infection from him. The disease commenced with great torpor of the stomach, which was shewn by his total aversion to solid food, and perpetual sickness; the watery stools, which were sometimes green, or of a darkish yellow, were owing to the acrimony, or acidity, of the contents of the bowels; which as well as the flatulency were occasioned by indigestion. This torpor of the stomach continued throughout the whole fever, and when it ceased, the fever ceased along with it. The contagious material of this fever I suppose to have been mixed with the saliva, and swallowed into the stomach; that it excited the vessels, which constitute the stomach, into the greatest irritative motion like arsenic; _which might not be perceived, and yet might render that organ paralytic or inirritable in a moment of time_; as animals sometimes die by one single exertion, and consequent paralysis, without a second struggle; as by lightning, or being shot through the back part of the brain; of both which I have seen instances. I had once an opportunity of inspecting two oxen, a few minutes after they were killed by lightning under a crab-tree on moist ground in long grass; and observed, that they could not have struggled, as the grass was not pressed or bent near them; I have also seen two horses shot through the cerebellum, who never once drew in their legs after they first stretched them out, but died instantaneously; in a similar manner the lungs seem to be rendered instantly inanimate by the fumes of burning sulphur. The lungs may be sometimes primarily affected with contagious matter floating in the atmosphere as well as the stomach, as mentioned in article 9. of this Supplement. But probably this may occur much less frequently, because the oxygene of the atmosphere does not appear to be taken into the blood by animal absorption, as the saliva in the stomach, but passes through the moist membranes into the blood, like the ethereal fluids of electricity or heat, or by chemical attraction, and in consequence the contagious matter may be left behind; except it may sometimes be absorbed along with the mucus; of which however in this case there appeared no symptoms. The tonsils are other organs liable to receive contagious matter, as in the small-pox, scarlet-fever, and in other sensitive inirritated fevers; but no symptom of this appeared here, as the tonsils were at no time of the fever inflamed, though they were in this child previously uncommonly large. The pain of the forehead does not seem to have been of the internal parts of the head, because the nerves, which serve the stomach, are not derived from the anterior part of the brain; but it seems to have been owing to a torpor of the external membranes about the forehead from their direct sympathy with those of the stomach; that is, from the deficient excitement of the sensorial power of association; and seemed in some measure to be relieved by the emetics and blisters. The pulsations of the heart were weaker and in consequence quicker than natural, owing to their direct sympathy with the torpid peristaltic motions of the stomach; that is to the deficient excitement of the sensorial power of association. The action of the cutaneous capillaries and absorbents were stronger than natural, as appeared by the perpetual heat and dryness of the skin; which was owing to their reverse sympathy with the heart and arteries. This weaker and quicker action of the heart and arteries, and the stronger action of the cutaneous capillaries and absorbents, continued throughout the disease, and may be said to have constituted the fever, of which the torpor of the stomach was the remote cause. His tongue was not very much furred or very dry, nor his breath very hot; which shewed, that there was no great increase of the action of the mucous absorbents, nor of the pulmonary capillaries, and yet sufficient to produce great emaciation. His urine was nearly natural both in quantity and colour; which shewed, that there was no increase of action either of the kidnies, or of the urinary absorbents. The bathing his legs and hands and face for half an hour twice a day seemed to refresh him, and sometimes made his pulse slower, and thence I suppose stronger. This seems to have been caused by the water, though subtepid, being much below the heat of his skin, and consequently contributing to cool the capillaries, and by satiating the absorbents to relieve the uneasy sensation from the dryness of the skin. He continued the use of three drops of tincture of opium from about the eighth day to the twenty-fourth, and for the three preceding days took along with if two large spoonfuls of an infusion of bark in equal parts of wine and water. The former of these by its stimulus seemed to decrease his languor for a time, and the latter to strengthen his returning power of digestion. The daily exacerbations or remissions were obscure, and not well attended to; but he appeared to be worse on the fourteenth or fifteenth days, as his pulse was then quickest, and his inattention greatest; and he began to get better on the twentieth or twenty-first days of his disease; for the pulse then became less frequent, and his skin cooler, and he took rather more food: these circumstances seemed to observe the quarter periods of lunation. XIV. _Termination of continued fever._ 1. When the stomach is primarily affected with torpor not by defect of stimulus, but in consequence of the previous exhaustion of its sensorial power; and not secondarily by its association with other torpid parts; it seems to be the general cause of the weak pulsations of the heart and arteries, and the consequent increased action of the capillaries, which constitute continued fever with weak pulse. In this situation if the patient recovers, it is owing to the renovation of life in the torpid stomach, as happens to the whole system in winter-sleeping animals. If he perishes, it is owing to the exhaustion of the body for want of nourishment occasioned by indigestion; which is hastened by the increased actions of the capillaries and absorbents. 2. When the stomach is primarily affected by defect of stimulus, as by cold or hunger; or secondarily by defect of the power of association, as in intermittent fevers; or lastly in consequence of the introduction of the sensorial power of sensation, as in inflammatory diseases; the actions of the heart and arteries are not diminished, as when the stomach is primarily affected with torpor by its previous exhaustion of sensorial power, but become greatly increased, producing irritative or inflammatory fever. Where this fever is continued, though with some remissions and exacerbations, the excessive action is at length so much lessened by expenditure of sensorial power, as to gradually terminate in health; or it becomes totally exhausted, and death succeeds the destruction of the irritability and associability of the system. 3. There is also another termination of the diseases in consequence of great torpor of the stomach, which are not always termed fevers; one of these is attended with so great and universal torpor, that the patient dies in the first cold fit; that is, within twelve hours or less of the first seizure; this is commonly termed sudden death. But the quickness of the pulse, and the coldness with shuddering, and with sick stomach, distinguished a case, which I lately saw, from the sudden deaths occasioned by apoplexy, or ruptured blood-vessels. In hemicrania I believe the stomach is always affected secondarily, as no quickness of pulse generally attends it, and as the stomach recovers its activity in about two whole days. But in the following case, which I saw last week, I suppose the stomach suddenly became paralytic, and caused in about a week the death of the patient. Miss ----, a fine young lady about nineteen, had bathed a few times, about a month before, in a cold spring, and was always much indisposed after it; she was seized with sickness, and cold shuddering, with very quick pulse, which was succeeded by a violent hot fit; during the next cold paroxysm she had a convulsion fit; and after that symptoms of insanity, so as to strike and bite the attendants, and to speak furious language; the same circumstances occurred during a third fit, in which I believe a strait waistcoat was put on, and some blood taken from her; during all this time her stomach would receive no nutriment, except once or twice a little wine and water. On the seventh day of the disease, when I saw her, the extremities were cold, the pulse not to be counted and she was unable to swallow, or to speak; a clyster was used with turpentine and musk and opium, with warm fomentations, but she did not recover from that cold fit. In this case the convulsion fit and the insanity seem to have been violent efforts to relieve the disagreeable sensation of the paralytic stomach; and the quick pulse, and returning fits of torpor and of orgasm, evinced the disease to be attended with fever, though it might have been called anorexia maniacalis, or epileptica. 4. Might not many be saved in these fevers with weak pulse for a few weeks by the introduction of blood into a vein, once in two or three days; which might thus give further time for the recovery of the torpid stomach? Which seems to require some weeks to acquire its former habits of action, like the muscles of paralytic patients, who have all their habits of voluntary associations to form afresh, as in infancy. If this experiment be again tried on the human subject, it should be so contrived, that the blood in passing from the well person to the sick one should not be exposed to the air; it should not be cooled or heated; and it should be measured; all which may be done in the following manner. Procure two silver pipes, each about an inch long, in the form of funnels, wide at top, with a tail beneath, the former something wider than a swan-quill, and the latter less than a small crow-quill. Fix one of these silver funnels by its wide end to one end of the gut of a chicken fresh killed about four or six inches long, and the other to the other end of the gut; then introduce the small end of one funnel into the vein of the arm of a well person downwards towards the hand; and laying the gut with the other end on a water-plate heated to 98 degrees in a very warm room; let the blood run through it. Then pressing the finger on the gut near the arm of the well person, slide it along so as to press out one gutful into a cup, in order to ascertain the quantity by weight. Then introduce the other end of the other funnel into a similar vein in the arm of the sick person upwards towards the shoulder; and by sliding one finger, and then another reciprocally, along the chicken's gut, so as to compress it, from the arm of the well person to the arm of the sick one, the blood may be measured, and thus the exact quantity known which is given and received. See Class I. 2. 3. 25. XV. _Inflammation excited in fever._ 1. When the actions of any part of the system of capillaries are excited to a certain degree, sensation is produced, along with a greater quantity of heat, as mentioned in the fifth article of this supplement. When this increased capillary action becomes still more energetic, by the combined sensorial powers of sensation with irritation, new fibres are secreted, or new fluids, (which harden into fibres like the mucus secreted by the silk-worm, or spider, or pinna,) from which new vessels are constructed; it is then termed inflammation: if this exists in the capillary vessels of the cellular membrane or skin only, with feeble pulsations of the heart and arteries, the febris sensitiva inirritata, or malignant fever, occurs; if the coats of the arteries are also inflamed, the febris sensitiva irritata, or inflammatory fever, exists. In all these fevers the part inflamed is called a phlegmon, and by its violent actions excites so much pain, that is, so much of the sensorial power of sensation, as to produce more violent actions, and inflammation, throughout the whole system. Whence great heat from the excited capillaries of the skin, large and quick pulsations of the heart, full and hard arteries, with great universal secretions and absorptions. These perpetually continue, though with exacerbations and remissions; which seem to be governed by solar or lunar influence. 2. In this situation there generally, I suppose, exists an increased activity of the secerning vessels of the brain, and consequently an increased production of sensorial power; in less violent quantity of this disease however the increase of the action of the heart and arteries may be owing simply to the accumulation of sensorial power of association in the stomach, when that organ is affected by sympathy with some inflamed part. In the same manner as the capillaries are violently and permanently actuated by the accumulation of the sensorial power of association in the heart and arteries, when the stomach is affected primarily by contagious matter, and the heart and arteries secondarily. Thus I suspect, that in the distinct small-pox the stomach is affected secondarily by sympathy with the infected tonsils or inoculated arm; but that in the confluent small-pox the stomach is affected primarily, as well as the tonsils, by contagious matter mixed with the saliva, and swallowed. 3. In inflammatory fevers with great arterial action, as the stomach is not always affected with torpor, and as there is a direct sympathy between the stomach and heart, some people have believed, that nauseating doses of some emetic drug, as of antimonium tartarizatum, have been administered with advantage, abating by direct sympathy the actions of the heart. This theory is not ill founded, and the use of digitalis, given in small doses, as from half a dram to a dram of the saturated tincture, two or three times a day, as well as other less violent emetic drugs, would be worth the attention of hospital physicians. Sickness might also be produced probably with advantage by whirling the patient in a chair suspended from the cieling by two parallel cords; which after being revolved fifty or one hundred times in one direction, would return with great circular velocity, and produce vertigo, similar I suppose to sea-sickness. And lastly the sickness produced by respiring an atmosphere mixed with one tenth of carbonated hydrogen, discovered by Mr. Watt, and published by Dr. Beddoes, would be well worthy exact and repeated experiment. 4. Cool air, cool fomentations, or ablutions, are also useful in this inflammatory fever; as by cooling the particles of blood in the cutaneous and pulmonary vessels, they must return to the heart with less stimulus, than when they are heated above the natural degree of ninety-eight. For this purpose snow and ice have been scattered on the patients in Italy; and cold bathing has been used at the eruption of the small pox in China, and both, it is said, with advantage. See Class III. 2. 1. 12. and Suppl. I. 8. 5. The lancet however with repeated mild cathartics is the great agent in destroying this enormous excitement of the system, so long as the strength of the patient will admit of evacuations. Blisters over the painful part, where the phlegmon or topical inflammation is situated, after great evacuation, is of evident service, as in pleurisy. Warm bathing for half an hour twice a day, when the patient becomes enfeebled, is of great benefit, as in peripneumony and rheumatism. 6. When other means fail of success in abating the violent excitement of the system in inflammatory diseases, might not the shaved head be covered with large bladders of cold water, in which ice or salt had been recently dissolved; and changed as often as necessary, till the brain is rendered in some degree torpid by cold?--Might not a greater degree of cold, as iced water, or snow, be applied to the cutaneous capillaries? 7. Another experiment I have frequently wished to try, which cannot be done in private practice, and which I therefore recommend to some hospital physician; and that is, to endeavour to still the violent actions of the heart and arteries, after due evacuations by venesection and cathartics, by gently compressing the brain. This might be done by suspending a bed, so as to whirl the patient round with his head most distant from the center of motion, as if he lay across a millstone, as described in Sect. XVIII. 20. For this purpose a perpendicular shaft armed with iron gudgeons might have one end pass into the floor, and the other into a beam in the cieling, with an horizontal arm, to which a small bed might be readily suspended. By thus whirling the patient with increasing velocity sleep might be produced, and probably the violence of the actions of the heart and arteries might be diminished in inflammatory fevers; and, as it is believed, that no accumulation of sensorial power would succeed a torpor of the origin of the nerves, either thus procured by mechanical compression, or by the bladder-cap of cold water above described, the lives of thousands might probably be saved by thus extinguishing the exacerbations of febrile paroxysms, or preventing the returns of them. In fevers with weak pulse sleep, or a degree of stupor, thus produced, might prevent the too great expenditure of sensorial power, and thus contribute to preserve the patient. See Class I. 2. 5. 10. on stupor. What might be the consequence of whirling a person with his head next the center of motion, so as to force the blood from the brain into the other parts of the body, might be discovered by cautious experiment without danger, and might probably add to our ability of curing fever. XVI. _Recapitulation._ 1. The sensorial power causes the contraction of the fibres, and is excited into action by four different circumstances, by the stimulus of external bodies, by pain or pleasure, by desire or aversion, or by the previous motions of other contracting fibres. In the first situation it is called the sensorial power of irritation, in the second the sensorial power of sensation, in the third the sensorial power of volition, and in the fourth the sensorial power of association. Many parts of the body are excited into perpetual action, as the sanguiferous vessels consisting of the heart, arteries, and veins; others into nearly perpetual action, as the conglomerate and capillary glands; and others into actions still somewhat less frequent, as the alimentary canal, and the lacteal and lymphatic absorbents with their conglobate glands: all these are principally actuated by the sensorial powers of irritation, and of association; but in some degree or at some times by those of sensation, and even of volition. There are three kinds of stimulus, which may easily be occasionally diminished, that of heat on the skin, of food in the stomach, and of the oxygenous part of the atmosphere, which mixes with the blood in respiration, and stimulates the heart and arteries. 2. When any parts, which are naturally excited into perpetual action by stimulus, become torpid or less active from decrease of that stimulus; there first occurs a decrease of the activity of the parts next catenated with them; thus going into cold water produces a torpor of the capillary vessels of the lungs, as is known by the difficult respiration, which immediately occurs; for the sensorial power of association, which naturally contributes to actuate the lungs, is now less excited by the decreased actions of the cutaneous vessels, with which they are catenated. This constitutes the cold fit of fever. There next occurs an accumulation of the sensorial power of irritation in the parts, which were torpid from defect of stimulus, as the cutaneous vessels for instance when exposed to cold air; and a similar accumulation of the sensorial power of association occurs in the parts which were catenated with the former, as the vessels of the lungs in the example above mentioned. Whence, if the subduction of stimulus has not been too great, so as to impair the health of the part, the activity of the irritative motions returns, even though the stimulus continues less than usual; and those of the associate motions become considerably increased, because these latter are now excited by the previous fibrous motions, which now act as strong or stronger than formerly, and have also acquired an accumulation of the sensorial power of association. This accounts for the curious event of our becoming warm in a minute or two after remaining in water of about 80 degrees of heat, as in the bath at Buxton; or in the cold air of a frosty morning of about 30 degrees of heat. But if the parts thus possessed of the accumulated sensorial powers of irritation and of association be exposed again to their natural quantity of stimulus, a great excess of activity supervenes; because the fibres, which possess accumulated irritation, are now excited by their usual quantity of stimulus; and those which possess accumulated association, are now excited by double or treble the quantity of the preceding irritative fibrous motions, with which they are catenated; this constitutes the hot fit of fever. Another important circumstance occurs, when the parts, which are torpid from decreased stimulus, do not accumulate a quantity of sensorial power sufficient for the purpose of renewing their own natural quantity of action; but are nevertheless not so torpid, as to have the life of the part impaired. In this situation the superabundance of the accumulated power of irritation contributes to actuate the associate motions next catenated with them. Thus, when a person breathes air with less oxygene than natural, as by covering his head in bed, and thus respiring the same atmosphere repeatedly, the heart and arteries become less active by defect of the stimulus of oxygene; and then the accumulation of sensorial power of irritation becomes instantly very great, as these organs are subject to perpetual and energetic action. This accumulation nevertheless is not so great as to renew their own activity under this defect of stimulus, but yet is in sufficient abundance to increase the associability of the next link of catenation, that is, to actuate the capillaries of the skin with great and perpetual increase of energy. This resembles continued fever with weak pulse; in which the accumulation of the sensorial power caused by the lessened motions of the heart and arteries, actuates the capillaries with increase of energy. 3. When the accumulation of the sensorial power of association, which is caused as above explained by deficient excitement owing to the lessened quantity of action of the irritative fibrous motions, with which the associate train is catenated, is not in quantity sufficient to renew the natural actions of the first link of an associate train of motions; it is nevertheless frequently so abundant as to actuate the next link of the associated train with unnatural energy by increasing its associability; and that in a still greater degree if that second link of the associated train was previously in a torpid state, that is, had previously acquired some accumulation of the sensorial power of association. This important circumstance of the animal economy is worthy our most accurate attention. Thus if the heart and arteries are deprived of their due quantity of the stimulus of oxygene in the blood, a weak and quick pulse ensues, with an accumulation of the sensorial power of irritation; next follows an increase of the action of the capillaries by the superabundance of this accumulated power of irritation; but there also exists an accumulation of the power of association in these acting capillaries, which is not now excited by the deficient actions of the heart and arteries; but which by its abundance contributes to actuate the next link of association, which is the sick stomach in the case related from Sydenham in Class IV. 1. 1. 2. and explained in this Supplement I. 4. And as this sick stomach was in a previous state of torpor, it might at the same time possess an accumulation of some sensorial power, which, if it was of association, would be thus more powerfully excited by the increased actions of the capillaries; which existed in consequence of the weak action of the heart and arteries. This also resembles in some respects the continued fevers with weak pulse, and with increased activity of the capillaries. 4. When a torpor of some irritative motions occurs from a previous exhaustion of the sensorial power of irritation by the action of some very great stimulus, it is long before any accumulation of the sensorial power of irritation is produced; as is experienced in the sickness and languor, which continues a whole day after a fit of drunkenness. But nevertheless there occurs an accumulation of the sensorial power of association in the first link of the associate train of motions, which is catenated with these torpid irritative ones; which accumulation is owing to deficient excitement of that sensorial power in the first link of the associate train. This first link therefore exists also in a less active or torpid state, but the accumulation of the sensorial power of association by its superabundance contributes to actuate the second link of the associate train with unnatural quantity of motion; and that though its own natural quantity of the power of association is not excited by the deficient action of preceding fibrous motions. When this happens to the stomach, as after its irritative motions have been much exerted from the unnatural stimulus of wine, or opium, or of contagious matter mixed with the saliva, a torpor or inactivity of it succeeds for a greater or less length of time; as no accumulation of the sensorial power of irritation can occur, till the natural quantity, which has been previously expended, is first restored. Then the heart and arteries which are next in catenation, become less active from the want of sufficient excitement of the sensorial power of association, which previously contributed to actuate them. This sensorial power of association therefore becomes accumulated, and by its superabundance contributes to actuate the link next in association, which has thus acquired so great a degree of associability, as to overbalance the less quantity of the excitement of it by the torpid action of the previous or first associate link. This happens to the capillaries, when the heart and arteries are affected as above by the torpor of the stomach, when it is occasioned by previous great expenditure of its sensorial power, and thus constitutes fever with weak pulse, which is here termed inirritative fever, typhus mitior. 5. When a deficiency of stimulus is too great or too long continued, so as to impair the life of the part, no further accumulation of sensorial power occurs; as when the skin is long exposed to cold and damp air. In that case the link in catenation, that is, the first of the associate train, is rendered torpid by defect of excitement of its usual quantity of the sensorial power of association, and from there being no accumulation of the sensorial power of irritation to increase its associability, and thus to contribute to actuate it by overbalancing the defect of the excitement of its association. Thus on riding long and slowly on a cold and damp day, the exhalation of the vapour, which is impinged on the skin, as the traveller proceeds, carries away his warmth faster, than it is generated within the system; and thus the capillaries of the skin have their actions so much impaired after a time, that no accumulation of the sensorial power of irritation occurs; and then the stomach, whose motions are catenated with those of the capillaries, ceases to act from the deficient excitement of the power of association; and indigestion and flatulency succeed, instead of the increased digestion and hunger, which occur, when the cutaneous capillaries are exposed to a less degree of cold, and for a shorter time. In which latter situation the accumulation of the sensorial power of irritation increases by its superabundance the associability of the fibres of the stomach, so as to overbalance the defect of the excitement of their association. 6. The stomach is affected secondarily in fevers with strong pulse, as in those with weak pulse it is affected primarily. To illustrate this doctrine I shall relate the following case of Mr. Y----. He was a young man rather intemperate in the use of wine or beer, and was seized with a cold fit, and with a consequent hot one with strong pulse; on examining his hypochondrium an oblong tumour was distinctly felt on the left side of the stomach, which extended six or eight inches downward, and was believed to be a tumour of the spleen, which thus occasioned by its torpor the cold fit and consequent hot fit of fever with strong pulse. This fever continued, though with remissions, for two or three weeks; and the patient repeatedly lost blood, used cathartics with calomel and sena, and had frequent antimonial and saline medicines. And after he was much weakened by evacuations, the peruvian bark and small doses of steel removed the fever, but the tumour remained many years during the remainder of his life. In this case the tumour of the spleen was occasioned by the torpor of the absorbent vessels; while the secerning vessels continued somewhat longer to pour their fluids into the cells of it. Then the inactivity of this viscus affected the whole system with torpor by the deficient excitement of the sensorial power of association, which contributes along with the irritation caused by their specific stimuli to actuate the whole sanguiferous, secerning, and absorbent vessels; and along with these the stomach, which possesses perhaps greater mobility, or promptitude to torpor or to orgasm, than any other part. And after a time all these parts recover their actions by the accumulation of their sensorial power of association. But the spleen not recovering its action from the accumulation of its power of irritation, as appeared from the continuance of the tumor, still affects the stomach by its defective irritative motions ceasing to excite the association, which ought to contribute to actuate it. Hence the stomach continues torpid in respect to its motions, but accumulates its power of association; which is not excited into action by the defective motions of the spleen; this accumulation of the sensorial power of association now by its superabundance actuates the next link of associate motions, which consists of the heart and arteries, into greater energy of action than natural, and thus causes fever with strong pulse; which, as it was supposed to be most frequently excited by increase of irritation, is called irritative fever or synocha. Similar to this in the small pox, which is given by inoculation, the stomach is affected secondarily, when the fever commences; and hence in this small-pox the pulsations of the heart and arteries are frequently stronger than natural, but never weaker, for the reasons above given. Whereas in that small-pox, which is caused by the stomach being primarily affected, by the contagious matter being swallowed with the saliva, whether the tonsils are at the same time affected or not, the pulsations of the heart and arteries become weak, and the inirritative fever is produced, as explained above, along with the confluent small-pox. This unfolds the cause of the mildness of the inoculated small-pox; because in this disease the stomach is affected secondarily, whereas in the natural small-pox it is frequently affected primarily by swallowing the contagious matter mixed with saliva. In the measles I suppose the contagious matter to be dissolved in the air, and therefore not liable to be mixed with the saliva; whereas the variolous matter is probably only diffused in the air, and thence more readily mixed with the saliva in the mouth during respiration. This difference appears more probable, as the small-pox I believe is always taken at a less distance from the diseased person than is necessary to acquire the measles. The contagion of the measles affects the membranes of the nostrils, and the secretion of tears in consequence, but never I suspect the stomach primarily, but always secondarily; whence the pulsation of the heart and arteries is always stronger than natural, so as to bear the lancet at any period of the disease. The great mildness sometimes, and fatality at other times, of the scarlet fever may depend on the same circumstance; that is, on the stomach being primarily or secondarily affected by the contagious matter, observing that the tonsils may be affected at the same time with the stomach. Should this prove to be the case, which future observations must determine, what certain advantage must arise from the inoculation of this disease! When it is received by the skin primarily I suppose no sore throat attends it, nor fever with weak pulse; when it is received by the stomach primarily, the tonsils are affected at the same time, and the torpor of the stomach produces inirritative fever, and the mortification of the tonsils succeeds. We may hence conclude, that when the torpor of the stomach is either owing to defect of stimulus, which is not so great as to impair the life of the part, as in moderate hunger, or in swallowing iced water, or when its torpor is induced by its catenation or association with other torpid parts, as in the commencement of intermittent fevers, and inoculated small-pox, that the subsequent action of the heart and arteries is generally increased, producing irritative fever. Which is owing to the accumulation, of the sensorial power of irritation in one case, and of association in the other, contributing to actuate the next link of the catenated or associated motions. But when the torpor of the stomach is induced by previous exhaustion of its sensorial powers of irritation or of association by continued violent action, as by the stimulus of digitalis, or of contagious matter, or after intoxication from wine or opium, a weaker action of the heart and arteries succeeds, because there is no accumulation of sensorial power, and a deficient excitement of association. And finally, as this weak action of the heart and arteries is not induced by exhaustion of sensorial power, but by defect of the excitement of association, the accumulation of this power of association increases the action of the capillaries, and thus induces inirritative fever. 7. When any part of the system acts very violently in fevers, the sensorial power of sensation is excited, which increases the actions of the moving system; whereas the pain, which arises from decreased irritative motions, as in hemicrania, seems to exhaust a quantity of sensorial power, without producing or increasing any fibrous actions. When the stomach is primarily affected, as in inirritative fevers from contagion, and in such a manner as to occasion pain, the action of the capillaries seems to be increased by this additional sensorial power of sensation, whence extensive inflammation or mortification; but when the stomach and consequently the heart and arteries continue their torpidity of action; as in confluent small-pox, and fatal scarlatina; this constitutes sensitive inirritative fever, or typhus gravior. But when the stomach is secondarily affected, if the sensorial power of sensation is excited, as in pleurisy or peripneumony, the actions of the heart and arteries are violently increased, and of all the moving system along with them. Thus the peripneumony is generally induced by the patient respiring very cold air, and this especially after being long confined to warm air, or after being much fatigued and heated by excessive labour or exercise. For we can cover the skin with more clothes, when we feel ourselves cold; but the lungs not having the perception of cold, we do not think of covering them, nor have the power to cover them, if we desired it; and the torpor, thus produced is greater, or of longer duration, in proportion to the previous expenditure of sensorial power by heat or exercise. This torpor of the lungs affects the skin with shuddering, and the stomach is also secondarily affected; next follows the violent action of the lungs from the accumulation of the power of irritation, and an inflammation of them follows this violent action. While the stomach recovers its activity by the increase of the excitement of the sensorial power of association, and along with it the heart and arteries, and the whole moving system. Hence this inflammation occurs during the hot fit of fever, and no cold fit succeeds, because the excess of the sensorial power of sensation prevents a succeeding torpor. These new motions of certain parts of the system produce increased secretions of nutritious or organic mucus, which forms new vessels; these new vessels by their unusual motions produce new kinds of fluids; which are termed contagious, because they have the power, when introduced into a healthy body, of producing similar actions and effects, with or without fever, as in the small-pox and measles, or in the itch and venereal disease. If any of these contagious matters affect the stomach with torpor either by their stimulus immediately applied, or by its sympathy with the parts first diseased, a fever is produced with sickness and want of appetite; as in small-pox, and scarlatina. If the stomach is not affected by contagious matter, no fever succeeds, as in itch, tinea, syphilis. All these contagious matters are conceived to be harmless, till they have been exposed to the air, either openly or through a moist membrane; from which they are believed to acquire oxygene, and thence to become some kinds of animal acids. As the preparations of mercury cure venereal ulcers; as a quarter of a grain of sublimate dissolved in wine, and given thrice a day; this effect, seems to be produced either by its stimulating the absorbents in the ulcer to absorb the venereal matter before it has acquired oxygene; or by afterwards uniting with it chemically, and again depriving it of its acquired acidity. On either supposition it might probably be given with advantage in small-pox, and in all infectious diseases, both previous to their commencement, and during their whole progress. 8. The cold fits of intermittent fevers are caused by the torpor of some part owing to deficient irritation, and of the other parts of the system from deficient association. The hot fits are owing first to the accumulation of irritation in the part primarily affected, if it recovers its action, which does not always happen; and secondly to the accumulation of association in the other parts of the system, which during health are subject to perpetual action; and lastly also to the greater excitement of the power of association, when the part primarily affected recovers its irritability, and acts with greater energy than natural. The deficient secretions in the cold fit depend on the torpor of the glandular system; and the increased secretions in the hot fit on their more energetic action. The thirst in the cold fit is owing to the deficient absorption from the skin, cellular membrane, and bladder; the thirst in the hot fit is owing to the too great dissipation of the aqueous part of the blood. The urine is pale and in small quantity in the cold fit from deficient secretion of it, and from deficient absorption of its aqueous parts; it is high coloured, and sometimes deposits a sediment, in the hot fit from the greater secretion of it in the kidneys, and the greater absorption of its aqueous and saline part in the bladder. The dryness and scurf on the tongue and nostrils is owing to the increased heat of the air expired from the lungs, and consequent greater evaporation of the aqueous part of the mucus. The sweats appear in consequence of the declension of the hot fit, owing to the absorbent vessels of the skin losing their increased action sooner than the secerning ones; and to the evaporation lessening as the skin becomes cooler. The returns of the paroxysms are principally owing to the torpor of some less essential part of the system remaining after the termination of the last fit; and are also dependent on solar or lunar diurnal periods. The torpor of the part, which induces the cold paroxysm, is owing to deficient irritation occasioned either by the subduction of the natural stimuli of food, or water, or pure air, or by deficiency of external influences, as of heat, or of solar or lunar gravitation. Or secondly, in consequence of the exhaustion of sensorial power by great previous exertions of some parts of the system, as of the limbs by great labour or exercise, or of the stomach by great stimulus, as by contagious matter swallowed with the saliva, or by much wine or opium previously taken into it. Or lastly a torpor of a part may be occasioned by some mechanic injury, as by a compression of the nerves of the part, or of their origin in the brain; as the sitting long with one leg crossed over the other occasions numbness, and as a torpor of the stomach, with vomiting frequently precedes paralytic strokes of the limbs. As sleep is produced, either by defect of stimulus, or by previous exhaustion of sensorial power; so the accumulation of the sensorial power of volition in those muscles and organs of sense, which are generally obedient to it, awakens the sleeping person; when it has increased the quantity of voluntarity so much as to overbalance the defect of stimulus in one case, and the exhaustion of sensorial power in the other; which latter requires a much longer time of sleep than the former. So the cold paroxysm of fever is produced either by defect of stimulus, or by previous exhaustion of the sensorial power of some part of the system; and the accumulation of the sensorial power of irritation in that part renews the action of it, when it has increased its irritability so much as to overbalance the defect of stimulus in one case and the exhaustion of sensorial power in the other; which latter requires a much longer torpor or cold fit than the former. But in the cold paroxysm of fever besides the torpor of one part of the system from defect of irritation, the remainder of it becomes torpid owing to defect of excitement of the sensorial power of association by the lessened action of the part first affected. This torpor of the general system remains, till the accumulation of the sensorial power of association has increased the associability so much as to overbalance the defect of the excitement of association; then the torpor ceases, and if the first affected part has recovered its activity the other parts are all thrown into excess of action by their increased associability, and the hot fit of fever is produced. 9. In the continued fevers with strong pulse the stomach is affected secondarily, and thus acts feebly from deficient excitement of the power of association; but the accumulation of the power of association thus produced in an organ subject to perpetual and energetic action, is so great as to affect the next link of the associate train, which consists of the heart and arteries; these therefore are exerted perpetually with increase of action. In continued fevers with weak pulse the torpid stomach is affected primarily by previous exhaustion of its irritability by stimulus, as of contagious matter swallowed into it. The heart and arteries act feebly from deficient excitement of the power of association, owing to the torpor of the stomach, with which they are catenated; but the accumulation of the power of association, thus produced in organs subject to perpetual and energetic motion, is so great, as to affect the next link of the associate train; which consists of the capillaries of the skin or other glands; these therefore are exerted perpetually with great increase of action. The continued fevers with strong pulse terminate by the reduction or exhaustion of the sensorial power by violent action of the whole system; which is followed either by return of health with the natural quantity of irritability, and of associability, or by a total destruction of them both, and consequent death. In continued fevers with weak pulse the stomach remains torpid during the whole course of the fever; and at length by the recovery of its irritability and sensibility effects the cure of it. Which generally happens about the first, second, or third quarter of the lunar period, counted from the commencement of the disease, or continues a whole lunation, and sometimes more; which gave rise to what are termed critical days. See Sect. XXXVI. 4. on this subject. If the stomach does not recover from its torpor, the patient becomes emaciated, and dies exhausted by the continuance of the increased action of the capillaries and absorbents, and the want of nourishment. The cure of continued fever with weak pulse consists first in weakening the undue action of the capillaries of the skin by ablution with cold water from 32 to 80 degrees of heat; or by exposing them to cool air. Secondly by invigorating the actions of the stomach, by decreasing them for a time, and thence accumulating the power of irritation, as by an emetic, or by iced water, or iced wine. Or by increase of stimulus, as by bark, wine, opium, and food, in small quantities frequently repeated. Or by renewing the action of the stomach by slight electric shocks. Or by fomenting it frequently with water heated to 96 or 100 degrees. Or lastly by exciting its power of association with other parts of the system, as by a blister; which succeeds best when the extremities are cool; or by swinging, as in vertigo rotatoria. If by the stimulus of the Peruvian bark on the fibres of the stomach, they regain their due action, the heart and arteries also regain their due action; as their sensorial power of association is now excited, and expended as usual. And as there is then no accumulation of sensorial power in the heart and arteries, the capillaries cease to act with too great energy, and the fever is cured. Thirdly. If the heart and arteries could be themselves stimulated into greater action, although the stomach remained torpid, they might probably by expending a greater quantity of the sensorial power of irritation, prevent an accumulation of the sensorial power of association, (for these may possibly be only different modes of action of the spirit of animation,) and thus the too great action of the capillaries might be prevented and the fever cease. This new mode of cure might possibly be accomplished, if the patient was to breathe a gallon or two of pure or diluted oxygene gas frequently in a day; which by passing through the moist membranes of the lungs and uniting with the blood might render it more stimulant, and thus excite the heart and arteries into greater action. Fourthly. Greater energy might probably be given to the whole system, and particularly to those parts which act too feebly in fevers, as the stomach and the heart and arteries, if the action of the secerning vessels of the brain could be increased in energy; this is probably one effect of all those drugs, which when given in large quantity induce intoxication, as wine and opium. And when given with great caution in small quantities uniformly repeated, as from three drops to five of the tincture of opium, but not more, every six hours, I believe they supply an efficacious medicine in fevers with great arterial debility; and the more so, if the Peruvian bark be exhibited alternately every six hours along with them. There are other means of exciting the vessels of the brain into action; as first by decreasing the stimulus of heat by temporary cold fomentation; secondly, increasing the stimulus of heat by long continued warm fomentation; thirdly, by electricity, as very small shocks passed through it in all directions; and lastly by blisters on the head. All those require to be used with great caution, and especially where there exists an evident stupor, as the removing of that is I believe frequently injurious. See stupor, Class I. 2. 5. 10. The cure of fever with strong pulse consists in the repeated use of venesection, gentle cathartics, diluents; medicines producing sickness, as antimonials, digitalis; or the respiration of carbonated hydrogen; or by respiration of atmospheric air lowered by a mixture of hydrogen, azote, or carbonic acid gas, or by compressing the brain by whirling in a decumbent posture, as if lying across an horizontal mill-stone. See the former parts of this supplement for the methods of cure both of fevers with strong and weak pulse. 10. When any difficulty occurs in determining the weak pulse from the strong one, it may generally be assisted by counting its frequency. For when an adult patient lies horizontally in a cool room, and is not hurried or alarmed by the approach of his physician, nor stimulated by wine or opium, the strong pulse seldom exceeds 118 or 120 in a minute; and the weak pulse is generally not much below 130, and often much above that number. Secondly in sitting up in bed, or changing the horizontal to a perpendicular posture, the quickness of the weak pulse is liable immediately to increase 10 or 20 pulsations in a minute, which does not I believe occur in the strong pulse, when the patient has rested himself after the exertion of rising. XVII. _Conclusion._ Thus have I given an outline of what may be termed the sympathetic theory of fevers, to distinguish it from the mechanic theory of Boerhaave, the spasmodic theory of Hoffman and of Cullen, and the putrid theory of Pringle. What I have thus delivered, I beg to be considered rather as observations and conjectures, than as things explained and demonstrated; to be considered as a foundation and a scaffolding, which may enable future industry to erect a solid and a beautiful edifice, eminent both for its simplicity and utility, as well as for the permanency of its materials,--which may not moulder, like the structures already erected, into the sand of which they were composed; but which may stand unimpaired, like the Newtonian philosophy, a rock amid the waste of ages! * * * * * ADDITIONS. * * * * * ADDITION I. At the end of the article Canities, in Class I. 2. 2. 11. please to add the following: As mechanical injury from a percussion, or a wound, or a caustic, is liable to occasion the hair of the part to become grey; so I suspect the compression of parts against each other of some animals in the womb is liable to render the hair of those parts of a lighter colour; as seems often to occur in black cats and dogs. A small terrier bitch now stands by me, which is black on all those parts, which were external, when she was wrapped up in the uterus, teres atque rotunda; and those parts white, which were most constantly pressed together; and those parts tawny, which were generally but less constantly pressed together. Thus the hair of the back from the forehead to the end of the tail is black, as well as that of the sides, and external parts of the legs, both before and behind. As in the uterus the chin of the whelp is bent down, and lies in contact with the fore part of the neck and breast; the tail is applied close against the division of the thighs behind; the inside of the hinder thighs are pressed close to the sides of the belly, all these parts have white hairs. The fore-legs in the uterus lie on each side of the face; so that the feet cover part of the temples, and compress the prominent part of the upper eye-brows, but are so placed as to defend the eye-balls from pressure; it is curious to observe, that the hair of the sides of the face, and of the prominent upper eye-brows, are tawny, and of the inside of the feet and legs, which covered them; for as this posture admitted of more change in the latter weeks of gestation, the colour of these parts is not so far removed from black, as of those parts, where the contact or compression was more uniform. Where this uterine compression of parts has not been so great as to render the hair white in other animals, it frequently happens, that the extremities of the body are white, as the feet, and noses, and tips of the ears of dogs and cats and horses, where the circulation is naturally weaker; whence it would seem, that the capillary glands, which form the hair, are impeded in the first instance by compression, and in the last by the debility of the circulation in them. See Class I. 1. 2. 15. This day, August 8th, 1794, I have seen a negro, who was born (as he reports) of black parents, both father and mother, at Kingston in Jamaica, who has many large white blotches on the skin of his limbs and body; which I thought felt not so soft to the finger, as the black parts. He has a white divergent blaze from the summit of his nose to the vertex of his head; the upper part of which, where it extends on the hairy scalp, has thick curled hair, like the other part of his head, but quite white. By these marks I supposed him to be the same black, who is described, when only two years old, in the Transactions of the American Philosophical Society, Vol. II. page 292, where a female one is likewise described with nearly similar marks. The joining of the frontal bones, and the bregma, having been later than that of the other sutures of the cranium, probably gave cause to the whiteness of the hair on these parts by delaying or impeding its growth. ADDITION II. The following extract from a letter of Dr. Beddoes on hydrocephalus internus, I esteem a valuable addition to the article on that subject at Class I. 2. 3. 12. "Master L----, aged 9 years, became suddenly ill in the night about a week before I saw him. On the day before the attack, he had taken opening medicines, and had bathed afterwards. He had complained of violently acute pain in his head, shrieked frequently, ground his teeth hard, could not bear to have his head raised from the pillow, and was torpid or deaf. His tongue was white, pulse 110 in the evening and full. As yet the pupil of the eye was irritable, and he had no strabismus. He had been bled with leeches about the head, and blistered. I directed mercurial inunction, and calomel from 3 to 6 grains to be taken at first every six, and afterwards every three hours. This plan produced no sensible effect, and the patient died on the 18th day after the seizure. He had convulsion fits two days preceding his death, and the well-known symptoms of hydrocephalus internus all made their appearance. From what I had seen and read of this disease, I believed it to belong to inflammations, and at an earlier period I should be tempted to bleed as largely as for pneumonia. The fluid found after death in the ventricules of the brain I impute to debility of the absorbents induced by inflammation. My reasons are briefly these; 1. The acuteness of the pain. 2. The state of the pulse. In the above case for the first 9 or 10 days it did not exceed 110, and was full and strong. 3. To find out whether any febrile alternations took place, Master L.'s feet were frequently felt, and they were found at times cold, and at other times of a dry heat. I have many times seen this disease, but the patients were too young, or too far advanced, to inform me, whether they had chillness succeeded by heat at its onset. 4. The disorders to which the young are more peculiarly liable afford a presumption, that hydrocephalus internus is an inflammatory disease; and this is confirmed by the regularity of the period, within which it finishes its course. And lastly, does it not happen more frequently than is suspected from external injury? I have just now been well informed, that Dr. Rush has lately cured five out of six patients by copious bleedings. I relate here the reasons for an opinion without pretending to a discovery. Something like this doctrine may be found in certain modern publications, but it is delivered in that vague and diffuse style, which I trust your example will banish from medical literature." Clifton, near Bristol, _July 28, 1795_. To this idea of Dr. Beddoes may be added, that the hydrocele generally succeeds an injury, and consequent inflammation of the bag, which contains it. And that other dropsies, which principally attend inebriates, are consequent to too great action of the mucous membranes by the stimulus of beer, wine, and spirits. And lastly, that as these cases of hydrocephalus end so fatally, a new mode of treating them is much to be desired, and deserves to be seriously attended to. ADDITION III. ON VERTIGO. _To be placed after the additional Note at the end of Vol. I. on this Subject._ Having reperused the ingenious Essay of Dr. Wells on Single Vision, and his additional observations in the Gentleman's Magazine on the apparent retrogression of objects in vertigo, I am induced to believe, that this apparent retrogression of objects is not always owing to the same cause. When a person revolves with his eyes closed, till he becomes vertiginous, and then stands still without opening them, he seems for a while to go forward in the same direction. This hallucination of his ideas cannot be owing to ocular spectra, because, as Dr. Wells observes, no such can have been formed; but it must arise from a similar continuance or repetition of ideas belonging to the sense of touch, instead of to the sense of vision; and should therefore be called a tangible, not a visual, vertigo. In common language this belief of continuing to revolve for some time, after he stands still, when a person has turned round for a minute in the dark, would be called a deception of imagination. Now at this time if he opens his eyes upon a gilt book, placed with other books on a shelf about the height of his eye, the gilt book seems to recede in the contrary direction; though his eyes are at this time kept quite still, as well as the gilt book. For if his eyes were not kept still, other books would fall on them in succession; which, when I repeatedly made the experiment, did not occur; and which thus evinces, that no motion of the eyes is the cause of the apparent retrocession of the gilt book. Why then does it happen?--Certainly from an hallucination of ideas, or in common language the deception of imagination. The vertiginous person still imagines, that he continues to revolve forwards, after he has opened his eyes; and in consequence that the objects, which his eyes happen to fall upon, are revolving backward; as they would appear to do, if he was actually turning round with his eyes open. For he has been accustomed to observe the motions of bodies, whether apparent or real, so much more frequently by the eye than by the touch; that the present belief of his gyration, occasioned by the hallucinations of the sense of touch, is attended with ideas of such imagined motions of visible objects, as have always accompanied his former gyrations, and have thus been associated with the muscular actions and perceptions of touch, which occurred at the same time. When the remains of colours are seen in the eye, they are termed ocular spectra; when remaining sounds are heard in the ear, they may be called auricular murmurs; but when the remaining motions, or ideas, of the sense of touch continue, as in this vertigo of a blindfolded person, they have acquired no name, but may be termed evanescent titillations, or tangible hallucinations. Whence I conclude, that vertigo may have for its cause either the ocular spectra of the sense of vision, when a person revolves with his eyes open; or the auricular murmurs of the sense of hearing, if he is revolved near a cascade; or the evanescent titillations of the sense of touch, if he revolves blindfold. All these I should wish to call vanishing ideas, or sensual motions, of those organs of sense; which, ideas, or sensual motions, have lately been associated in a circle, and therefore for a time continue to be excited. And what are the ideas of colours, when they are excited by imagination or memory, but the repetition of finer ocular spectra? What the idea of sounds, but the repetition of finer auricular murmurs? And what the ideas of tangible objects, but the repetition of finer evanescent titillations? The tangible, and the auricular, and the visual vertigo, are all perceived by many people for a day or two after long travelling in a boat or coach; the motions of the vessel, or vehicle, or of the surrounding objects, and the noise of the wheels and oars, occur at intervals of reverie, or at the commencement of sleep. See Sect. XX. 5. These ideas, or sensual motions, of sight, of hearing, and of touch, are succeeded by the same effects as the ocular spectra, the auricular murmurs, and the evanescent titillations above mentioned; that is, by a kind of vertigo, and cannot in that respect be distinguished from them. Which is a further confirmation of the truth of the doctrine delivered in Sect. III. of this work, that the colours remaining in the eyes, which are termed ocular spectra, are ideas, or sensual motions, belonging to the sense of vision, which for too long a time continue their activity. ADDITION IV. OF VOLUNTARY MOTIONS. A correspondent acquaints me, that he finds difficulty in understanding how the convulsions of the limbs in epilepsy can be induced by voluntary exertions. This I suspect first to have arisen from the double meaning of the words "involuntary motions;" which are sometimes used for those motions, which are performed without the interference of volition, as the pulsations of the heart and arteries; and at other times for those actions, which occur, where two counter volitions oppose each other, and the stronger prevails; as in endeavouring to suppress laughter, and to stop the shudderings, when exposed to cold. Thus when the poet writes, ------video meliora, proboque, Deteriora sequor.---- The stronger volition actuates the system, but not without the counteraction of unavailing smaller ones; which constitute deliberation. A second difficulty may have arisen from the confined use of the words "to will," which in common discourse generally mean to choose after deliberation; and hence our will or volition is supposed to be always in our own power. But the will or voluntary power, acts always from motive, as explained in Sect. XXXIV. 1. and in Class IV. 1. 3. 2. and III. 2. 1. 12. which motive can frequently be examined previous to action, and balanced against opposite motives, which is called deliberation; at other times the motive is so powerful as immediately to excite the sensorial power of volition into action, without a previous balancing of opposite motives, or counter volitions. The former of these volitions is exercised in the common purposes of life, and the latter in the exertions of epilepsy and insanity. It is difficult _to think without words_, which however all those must do, who discover new truths by reasoning; and still more difficult, when the words in common use deceive us by their twofold meanings, or by the inaccuracy of the ideas, which they suggest. ADDITION V. OF FIGURE. I feel myself much obliged by the accurate attention given to the first volume of Zoonomia, and by the ingenious criticisms bestowed on it, by the learned writers of that article both in the Analytical and English Reviews. Some circumstances, in which their sentiments do not accord with those expressed in the work, I intend to reconsider, and to explain further at some future time. One thing, in which both these gentlemen seem to dissent from me, I shall now mention, it is concerning the manner, in which we acquire the idea of figure; a circumstance of great importance in the knowledge of our intellect, as it shews the cause of the accuracy of our ideas of motion, time, space, number, and of the mathematical sciences, which are concerned in the mensurations or proportions of figure. This I imagine may have in part arisen from the prepossession, which has almost universally prevailed, that ideas are immaterial beings, and therefore possess no properties in common with solid matter. Which I suppose to be a fanciful hypothesis, like the stories of ghosts and apparitions, which have so long amused, and still amuse, the credulous without any foundation in nature. The existence of our own bodies, and of their solidity, and of their figure, and of their motions, is taken for granted in my account of ideas; because the ideas themselves are believed to consist of motions or configurations of solid fibres; and the question now proposed is, how we become acquainted with the figures of bodies external to our organs of sense? Which I can only repeat from what is mentioned in Sect. XIV. 2. 2. that if part of an organ of sense be stimulated into action, as of the sense of touch, that part so stimulated into action must possess figure, which must be similar to the figure of the body, which stimulates it. Another previous prepossession of the mind, which may have rendered the manner of our acquiring the knowledge of figure less intelligible, may have arisen from the common opinion of the perceiving faculty residing in the head; whereas our daily experience shews, that our perception (which consists of an idea, and of the pleasure or pain it occasions) exists principally in the organ of sense, which is stimulated into action; as every one, who burns his finger in the candle, must be bold to deny. When an ivory triangle is pressed on the palm of the hand, the figure of the surface of the part of the organ of touch thus compressed is a triangle, resembling in figure the figure of the external body, which compresses it. The action of the stimulated fibres, which constitute the idea of hardness and of figure, remains in this part of the sensorium, which forms the sense of touch; but the sensorial motion, which constitutes pleasure or pain, and which is excited in consequence of these fibrous motions of the organ of sense, is propagated to the central parts of the sensorium, or to the whole of it; though this generally occurs in less degree of energy, than it exists in the stimulated organ of sense; as in the instance above mentioned of burning a finger in the candle. Some, who have espoused the doctrine of the immateriality of ideas, have seriously doubted the existence of a material world, with which only our senses acquaint us; and yet have assented to the existence of spirit, with which our senses cannot acquaint us; and have finally allowed, that all our knowledge is derived through the medium of our senses! They forget, that if the spirit of animation had no properties in common with matter, it could neither affect nor be affected by the material body. But the knowledge of our own material existence being granted, which I suspect few rational persons will seriously deny, the existence of a material external world follows in course; as our perceptions, when we are awake and not insane, are distinguished from those excited by sensation, as in our dreams, and from those excited by volition or by association as in insanity and reverie, by the power we have of comparing the present perceptions of one sense with those of another, as explained in Sect. XIV. 2. 5. And also by comparing the tribes of ideas, which the symbols of pictures, or of languages, suggest to us, by intuitive analogy with our previous experience, that is, with the common course of nature. See Class III. 2. 2. 3. on Credulity. ADDITION VI. _Please to add the following in page 14, after line 20._ _Cold and hot Fit._ As the torpor, with which a fit of fever commences, is sometimes owing to defect of stimulus, as in going into the cold-bath; and sometimes to a previous exhaustion of the sensorial power by the action of some violent stimulus, as after coming out of a hot room into cold air; a longer time must elapse, before there can be a sufficient accumulation of sensorial power to produce a hot fit in one case than in the other. Because in the latter case the quantity of sensorial power previously expended must be supplied, before an accumulation can begin. The cold paroxysm commences, when the torpor of a part becomes so great, and its motions in consequence so slow or feeble, as not to excite the sensorial power of association; which in health contributes to move the rest of the system, which is catenated with it. And the hot fit commences by the accumulation of the sensorial power of irritation of the part first affected, either so as to counteract its deficient stimulus, or its previous waste of sensorial power; and it becomes general by the accumulation of the sensorial power of association; which is excited by the renovated actions of the part first affected; or becomes so great as to overbalance the deficient excitement of it. On all these accounts the hot fit cannot be supposed to bear any proportion to the cold one in length of time, though the latter may be the consequence of the former. See Suppl. I. 16. 8. ADDITION VII. ON WARMTH. _To be added at the end of the Species Sudor Calidus, in Class I. 1. 2. 3._ When the heat of the body in weak patients in fevers is increased by the stimulus of the points of flannel, a greater consequent debility succeeds, than when it is produced by the warmth of fire; as in the former the heat is in part owing to the increased activity of the skin, and consequent expenditure of sensorial power; whereas in the latter case it is in part owing to the influx of the fluid matter of heat. So the warmth produced by equitation, or by rubbing the body and limbs with a smooth brush or hand, as is done after bathing in some parts of the East, does not expend nearly so much sensorial power, as when the warmth is produced by the locomotion of the whole weight of the body by muscular action, as in walking, or running, or swimming. Whence the warmth of a fire is to be preferred to flannel shirts for weak people, and the agitation of a horse to exercise on foot. And I suppose those, who are unfortunately lost in snow, who are on foot, are liable to perish sooner by being exhausted by their muscular exertions; and might frequently preserve themselves by lying on the ground, and covering themselves with snow, before they were too much exhausted by fatigue. See Botan. Garden, Vol. II. the note on Barometz. ADDITION VIII. PUERPERAL FEVER. _To be added to Class II. 1. 6. 16._ A very interesting account of the puerperal fever, which was epidemic at Aberdeen, has been lately published by Dr. Alexander Gordon. (Robinson, London.) In several dissections of those, who died of this disease, purulent matter was found in the cavity of the abdomen; which he ascribes to an erysipelatous inflammation of the peritonæum, as its principal seat, and of its productions, as the omentum, mesentery, and peritonæal coat of the intestines. He believes, that it was infectious, and that the contagion was always carried by the accoucheur or the nurse from one lying-in woman to another. The disease began with violent unremitting pain of the abdomen on the day of delivery, or the next day, with shuddering, and very quick pulse, often 140 in a minute. In this situation, if he saw the patient within 12 or 24 hours of her seizure, he took away from 16 to 24 ounces of blood, which was always sizy. He then immediately gave a cathartic consisting of three grains of calomel, and 40 grains of powder of jalap. After this had operated, he gave an opiate at night; and continued the purging and the opiate for several days. He asserts, that almost all those, whom he was permitted to treat in this manner early in the disease, recovered to the number of 50; and that almost all the rest died. But that when two or three days were elapsed, the patient became too weak for this method; and the matter was already formed, which destroyed them. Except that he saw two patients, who recovered after discharging a large quantity of matter at the navel. And a few, who were relieved by the appearance of external erysipelas on the extremities. This disease, consisting of an erysipelatous inflammation, may occasion the great debility sooner to occur than in inflammation of the uterus; which latter is neither erysipelatous, I suppose, nor contagious. And the success of Dr. Gordon's practice seems to correspond with that of Dr. Rush in the contagious fever or plague at Philadelphia; which appeared to be much assisted by early evacuations. One case I saw some time ago, where violent unceasing pain of the whole abdomen occurred a few hours after delivery, with quick pulse; which ceased after the patient had twice lost about eight ounces of blood, and had taken a moderate cathartic with calomel. This case induces me to think, that it might be safer and equally efficacious, to take less blood at first, than Dr. Gordon mentions, and to repeat the operation in a few hours, if the continuance of the symptoms should require it. And the same in respect to the cathartic, which might perhaps be given in less quantity, and repeated every two or three hours. Nor should I wish to give an opiate after the first venesection and cathartic; as I suspect that this might be injurious, except those evacuations had emptied the vessels so much, that the stimulus of the opiate should act only by increasing the absorption of the new vessels or fluids produced on the surfaces of the inflamed membranes. In other inflammations of the bowels, and in acute rheumatism, I have seen the disease much prolonged, and I believe sometimes rendered fatal, by the too early administration of opiates, either along with cathartics, or at their intervals; while a small dose of opium given after sufficient evacuations produces absorption only by its stimulus, and much contributes to the cure of the patient. We may have visible testimony of this effect of opium, when a solution of it is put into an inflamed eye; if it be thus used previous to sufficient evacuation, it increases the inflammation; if it be used after sufficient evacuation, it increases absorption only, and clears the eye in a very small time. I cannot omit observing, from considering these circumstances, how unwise is the common practice of giving an opiate to every woman immediately after her delivery, which must often have been of dangerous consequence. END OF THE SECOND PART. * * * * * ZOONOMIÆ AUCTORI _S.P.D._ AMICUS. * * * * * _CURRUS TRIUMPHALIS MEDICINÆ._ * * * * * Currus it Hygeiæ, Medicus movet arma triumphans, Undique victa fugit lurida turma mali.---- Laurea dum Phoebi viridis tua tempora cingit, Nec mortale sonans Fama coronat opus; Post equitat trepidans, repetitque Senectus in aurem, Voce canens stridulà, "sis memor ipse mori!" * * * * * INDEX OF THE CLASSES. A. Abortion, i. 2. 1. 14. ---- from fear, iv. 3. 1. 7. ---- not from epilepsy, iii. 1. 1. 7. ---- not from hepatitis, ii. 1. 2. 12. Absorption of solids, i. 2. 2. 14. ---- of matter, ii. 1. 6. 2. and 6. ---- cellular, iv. 1. 1. 6. ---- from the lungs, iv. 3. 1. 5. Suppl. i. 8. 6. Abstinence of young ladies, ii. 2. 2. 1. Accumulation of feces, ii. 2. 2. 7. Acupuncture, iii. 1. 1. 8. Adipsia, ii. 2. 2. 2. Ægritudo ventriculi, i. 2. 4. 4. ---- See Sickness. Agrypnia. See Vigilia. Ague-cakes, Suppl. i. 2. 3. Alum in ulcers of the mouth, ii. 1. 3. 1. Ambition, iii. 1. 2. 9. Amaurosis, i. 2. 5. 5. Anasarca of the lungs, i. 2. 3. 16. Anger, iii. 1. 2. 17. Anger, tremor of, iv. 2. 3. 4. ---- blush of, iv. 2. 3. 5. Angina. See Tonsillitis. ---- pectoris. See Asthma painful. Anhelitus, ii. 1. 1. 4. Anhelatio spasmodica, i. 3. 3. 3. Annulus repens, ii. 1. 5. 10. Anorexia, ii. 2. 2. 1. ---- maniacalis, Suppl. i. 14. 3. ---- epileptica, ii. 2. 2. 1. iii. 1. 1. 7. Apepsia, i. 3. 1. 3. Suppl. i. 8. 11. Aphtha, ii. 1. 3. 17. Apoplexy, iii. 2. 1. 16. Appetite defective, ii. 2. 2. 1. ---- depraved, iii. 1. 2. 19. ---- from abstinence, ii. 2. 2. 1. ---- destroyed, iii. 1. 2. 20. ---- from epilepsy, ii. 2. 2. 1. Arm, pain of, iv. 2. 2. 13. ---- palsy of, iii. 2. 1. 4. Arsenic in tooth-ach, i. 2. 4. 12. ---- in head-ach, i. 2. 4. 11. Arthrocele, ii. 1. 4. 17. Arthropuosis, ii. 1. 4. 18. Arthritis. See Gout. Ascarides, i. 1. 4. 12. iv. 1. 2. 9. Ascites, i. 2. 3. 13. Associations affected four ways, iv. 1. 1. G. ---- how produced, iv. 1. 1. H. ---- distinct from catenations, iv. 1. 1. A. ---- three kinds of, iv. 1. 1. B. ---- tertian, iv. 1. 1. K. ---- of the fauces and pubis, iv. 1. 2. 7. ---- sensitive, a law of, iv. 2. 2. 2. ---- sensitive iv. 2. 1. ---- accumulates, Suppl. i. 8. 3. i. 11. 4. Asthma humoral, ii. 1. 1. 7. i. 3. 2. 8. ---- of infants, i. 1. 3. 4. ---- convulsive, iii. 1. 1. 10. ---- painful, iii. 1. 1. 11. Auditus acrior, i. 1. 5. 2. ---- imminutus, i. 2. 5. 6. Azote, Suppl. i. 9. 3. i. 11. 6. B. Bandages, ill effect of, ii. 1. 1. 12. ---- promote absorption, i. 1. 3. 13. Bath, cold, i. 2. 2. 1. ---- warm, Addit. vii. Beauty, iii. 1. 2. 4. ---- loss of, iii. 1. 2. 12. Bile-duct, pain of, iv. 2. 2. 4. Bile crystalized, i. 1. 3. 8. Bitter taste, i. 1. 3. 1. ---- not from bile, i. 1. 3. 1. Bleeding. See Hæmorrhage. Bladder, distention of, ii. 2. 2. 6. ---- stone of, i. 1. 3. 10. ---- catarrh of, ii. 1. 4. 11. Blindness, i. 2. 5. 5. Blush of anger, iv. 2. 3. 5. Suppl. i. 12. 7. ---- of guilt, iv. 2. 3. 6. Suppl. i. 12. 7. Bones, innutrition of, i. 2. 2. 14. ---- caries of, ii. 1. 4. 19. Borborigmus, i. 3. 1. 9. Bougies, ii. 1. 4. 11. Brachiorum paralysis, iii. 2. 1. 4. Brain stimulated, Suppl. i. 16. 9. Bronchocele, i. 2. 3. 20. Burns, i. 1. 3. 13. Butterflies, experiment on, i. 1. 2. 3. C. Cacositia, iii. 1. 2. 20. Calculi productio, i. 1. 3. 9. ii. 1. 2. 14. ---- renis, i. 1. 3. 9. iv. 2. 3. 3. ---- vesicæ, i. 1. 3. 10. iv. 2. 2. 2. Callico shirts, i. 1. 2. 3. Callus, i. 2. 2. 12. Canities. See Hair grey. Calor febrilis, i. 1. 2. 1. Calves fed on gruel, i. 1. 2. 5. ---- hydatides of, i. 2. 5. 4. Cancer, ii. 1. 4. 16. ii. 1. 6. 13. Cantharides, large dose of, iv. 2. 2. 2. Carbonic acid gas, Suppl. i. 9. 3. Cardialgia, i. 2. 4. 5. Carcinoma, ii. 1. 4. 16. ii. 1. 6. 13. Caries ossium, ii. 1. 4. 19. Cataract, i. 2. 2. 13. Catarrh, warm, i. 1. 2. 7. ---- cold, i. 2. 3. 3. ---- lymphatic, i. 3. 2. 1. ---- sensitive, ii. 1. 3. 5. ---- epidemic, ii. 1. 3. 6. ---- of dogs and horses, ii. 1. 3. 6. ---- from cold skin, iv. 1. 1. 5. ---- periodic, iv. 3. 4. 1. Catamenia, i. 2. 1. 11. iv. 2. 4. 7. Catalepsis, iii. 2. 1. 9. Cats, mumps of, ii. 1. 3. 4. Cephalæa frigida, i. 2. 4. 11. iv. 2. 2. 7. Charcoal tooth-powder, i. 2. 4. 12. Cheek, torpor of, iv. 2. 2. 1. Chicken pox, ii. 1. 3. 15. Chin-cough, ii. 1. 3. 8. Child-bed fever, ii. 1. 6. 16. Children, new born, ii. 1. 1. 12. ---- gripes and purging of, i. 1. 2. 5. Chlorosis, i. 2. 3. 10. Suppl. i. 8. 11. Chorea St. Viti, iv. 2. 3. 2. Citta, iii. 1. 2. 19. Clamor, iii. 1. 1. 3. Clavicular animals, ii. 1. 2. 6. Clavus hystericus, iv. 2. 2. 8. Claudicatio coxaria, i. 2. 2. 17. Cold in the head. See Catarrh. Colic, flatulent, i. 2. 4. 7. ---- from lead, i. 2. 4. 8. ---- hysteric, i. 2. 4. 7. iii. 1. 1. 8. Cold air in fevers, iii. 2. 1. 12. iv. 2. 4. 11. ---- effects of, iii. 2. 1. 17. ---- how to be used, iv. 1. 1. 4. Compassion, iii. 1. 2. 24. Consumption, ii. 1. 6. 7. Convulsion, iii. 1. 1. 5. ---- weak, iii. 1. 1. 5. ---- from bad air, iii. 1. 1. 5. ---- painful, iii. 1. 1. 6. iv. 2. 4. 5. Consternation, i. 1. 5. 11. Constipation, i. 1. 3. 5. ii. 2. 2. 7. Contagious matter of two kinds, ii. 1. 3. ---- is oxygenated, ii. 1. 5. ---- produces fever, how, Suppl. i. 16. 7. Cornea to perforate, i. 1. 3. 14. ---- scars of seen on milk, i. 1. 3. 14. Corpulency, i. 2. 3. 17. Coryza. See Catarrh. Costiveness, i. 1. 3. 5. ii. 2. 2. 7. Cough of drunkards, ii. 1. 1. 5. ---- hooping, ii. 1. 3. 8. ---- hepatic, iv. 2. 1. 8. ---- gouty, iv. 2. 1. 9. ---- periodic, iv. 2. 4. 6. iv. 3. 4. 2. ---- from cold feet, iv. 2. 1. 7. Cows, pestilence of, ii. 1. 3. 13. ---- bloody urine of, ii. 1. 3. 13. Cramp, iii. 1. 1. 13. ---- painful, iii. 1. 1. 14. ---- in diarrhoea, iv. 1. 2. 10. Crab-lice, i. 1. 4. 14. Credulity, iii. 2. 2. 3. Crines novi, i. 1. 2. 15. Croup, i. 1. 3. 4. ii. 1. 2. 4. ii. 1. 3. 3. Crusta lactea, ii. 1. 5. 12. Cutis arida, i. 1. 3. 6. Cynanche. See Tonsillitis. ---- parotidæa. See Parotitis. D. Darkness in fevers, i. 2. 5. 3. Deafness, two kinds of, i. 2. 5. 6. Debility, three kinds of, i. 2. 1. ---- and strength metaphors, i. 2. 1. Decussation of nerves, iii. 2. 1. 10. Deglutition, ii. 1. 1. 1. ---- involuntary, iv. 1. 3. 1. Dentition, i. 1. 4. 5. Dentium dolor a stridore, iv. 1. 2. 3. Descent of the uterus, i. 1. 4. 8. Diabetes, i. 3. 2. 6. ---- foul tongue in, i. 1. 3. 1. ---- irritative, iv. 3. 1. 1. ---- from fear, iv. 3. 1. 3. Diarrhoea warm, i. 1. 2. 5. ---- of infants, i. 1. 2. 5. ---- lymphatic, i. 3. 2. 4. ---- chyliferous, i. 3. 2. 5. ---- cold, i. 2. 3. 6. ---- rheumatic, iv. 1. 2. 16. ---- from fear, iv. 3. 1. 4. ---- from toothing, iv. 2. 2. 14. ---- in fevers, Suppl. i. 2. 4. ---- cure of, iv. 1. 1. f. Digestion increased by cold, iv. 1. 1. 4. ---- decreased by cold, iv. 2. 1. 6. Dilirium febrile, ii. 1. 7. 1. ---- of drunkenness, ii. 1. 7. 3. ---- maniacal, ii. 1. 7. 2. ---- in parotitis, iv. 1. 2. 19. Diluents, use of, ii. 1. 2. 1. Distention of the nipples, ii. 1. 7. 10. iv. 1. 2. 7. Diuretics useless in dropsy, i. 1. 3. 7. Dizziness. See Vertigo. Dogs, catarrh of, ii. 1. 3. 6. Dolor digiti sympathet, iv. 2. 2. 12. ---- ductus choledochi, iv. 2. 2. 4. ---- humeri in hepatitide, iv. 2. 2. 9. ---- pharyngis ab acido, iv. 2. 2. 5. ---- testium nephriticus, iv. 2. 2. 11. ---- urens, i. 1. 5. 10. Dracunculus, i. 1. 4. 13. Dreams, ii. 1. 7. 4. Dropsy of the brain, i. 2. 3. 12. ---- of the belly, i. 2. 3. 13. ---- of the chest, i. 2. 3. 14. ---- of the ovary, i. 2. 3. 15. ---- of the lungs, i. 2. 3. 16. ---- of the scrotum, i. 2. 3. 11. Dysentery, ii. 1. 3. 18. Dysmenorrhagia, i. 2. 1. 12. Dyspnoea from cold bath, iv. 2. 1. 5. ---- rheumatica, iv. 1. 2. 16. Dyspepsia, i. 3. 1. 3. ---- a frigore, iv. 2. 1. 6. Dysuria insensitiva, ii. 2. 2. 6. E. Ears, discharge behind, i. 1. 2. 9. ---- noise in them, iv. 2. 1. 15. Ear-ach, iv. 2. 2. 8. Ebrietas, i. 1. 1. 2. Education, iii. 2. 1. 8. iii. 1. 2. 24. ---- heroic, iii. 1. 2. 25. Egg boiled for inflamed eyes, ii. 1. 4. 1. ---- boiled soonest, Suppl. i. 7. ---- life of, iv. 1. 4. 1. Electric shocks, iv. 1. 4. 5. Electrized zinc and silver, i. 2. 5. 5. ---- in paralysis, ii. 1. 1. 9. ---- in scrophula, i. 2. 3. 21. ---- in hoarseness, iii. 2. 1. 5. Empyema, ii. 1. 6. 4. Enteralgia rheumatica, iv. 1. 2. 16. Enteritis, ii. 1. 2. 11. ---- superficialis, ii. 1. 3. 20. Epilepsy, iii. 1. 1. 7. iv. 3. 1. 6. ---- painful, iii. 1. 1. 8. iv. 2. 4. 4. ---- terminates with sleep, iii. 1. 1. ---- in parturition, iii. 1. 1. 7. ---- with indigestion, ii. 2. 2. 1. Epistaxis. See Hæmorraghia. Epoulosis. See Cicatrix. Erotomania, iii. 1. 2. 4. Eructation, voluntary, iv. 3. 3. 3. Eruption of small-pox, iv. 1. 2. 12. iv. 2. 2. 10. Erysipelas, iv. 1. 2. 17. ii. 1. 3. 2. iv. 2. 4. 10. ---- seldom suppurates, why, ii. 1. 3. 2. Esuries, i. 2. 4. 2. Evil, i. 2. 3. 21. Expectoration, warm, i. 1. 2. 8. ---- solid, i. 1. 3. 4. ---- cold, i. 2. 3. 4. Exsudation behind the ears, i. 1. 2. 9. Eyes, blue under the, i. 2. 2. 2. ii. 1. 4. 4. Eyelid inverted, cure of, ii. 1. 1. 8. ---- coloured with antimony, ii. 1. 4. 3. F. Face, pimpled, ii. 1. 4. 6. ---- red after meals, Suppl. i. 12. 7. ---- flushed after dinner, iv. 1. 1. 1. Fat people why short breathed, ii. 1. 1. 4. Fear, syncope from, i. 2. 1. 4. ---- abortion from, iv. 3. 1. 7. ---- produces absorption, ii. 1. 6. 4. ---- paleness in, iv. 3. 1. 5. ---- of death, iii. 1. 2. 14. ---- of hell, iii. 1. 2. 15. ---- of poverty, iii. 1. 2. 13. Feet cold produces heartburn. Suppl. i. 8. 5. ---- fetid, i. 1. 2. 14. ---- cold in small-pox, iv. 2. 2. 10. Fevers, five kinds, ii. 1. 2. Suppl. i. 1. 2. ---- irritative, i. 1. 1. 1. iv. 1. 1. 8. ---- inirritative, i. 2. 1. 1. iv. 2. 1. 19. Suppl. i. 1. 2. ---- sensitive, ii. 1. 6. 1. ---- sensitive irritated, ii. 1. 2. 1. ---- sensitive inirritated, ii. 1. 3. 1. ---- intermit, why, Suppl. i. ---- continue, why, Suppl. i. ---- periods of, iv. 2. 4. 11. ---- simple, Suppl. i. 1. ---- compound, Suppl. i. 2. ---- termination of cold fit, Suppl. i. 3. ---- return of cold fit, Suppl. i. 4. ---- sensation in, Suppl. i. 5. ---- circles of motions in, Suppl. i. 6. ---- cold and hot fits, Suppl. i. 7. ---- continued, Suppl. i. 8. ---- torpor of lungs in, Suppl. i. 9. 1. ---- not determinable in cold fit, i. 1. 1. 1. ---- frequency of pulse in, i. 1. 1. 1. ---- not an effort to cure, i. 1. 2. 3. ---- puerperal, ii. 1. 6. 16. i. 2. 4. 9. ---- from inclosed matter, ii. 1. 6. 2. ---- from aerated matter, ii. 1. 6. 6. ---- from contagious matter, ii. 1. 6. 11. ---- from contagious sanies, ii. 1. 6. 15. ---- torpor of the stomach, Suppl. i. 12. ---- case of, Suppl. i. 13. ---- termination of, Suppl. i. 14. ---- inflammation excited, Suppl. i. 15. ---- returns of, Suppl. i. 4. ---- when cold air in, Suppl. i. 2. 2. ---- sympathetic, theory of, Suppl. i. ---- duration of explained, Suppl. i. 2. 5. Fingers, playing with, iv. 1. 3. 4. ---- pain of, iv. 2. 2. 12. Fish live longer with injured brain, i. 2. 5. 10. Fistula in ano, ii. 1. 4. 10. ---- lacrymalis, ii. 1. 4. 9. ---- urethra, ii. 1. 4. 11. Flannel shirt in diarrhoea, iv. 1. 1. 3. ---- injurious in summer, i. 1. 2. 3. Fluor albus warm, i. 1. 2. 11. ---- cold, i. 2. 3. 7. Frigus febrile, i. 2. 2. 1. ---- chronicum, i. 2. 2. 1. G. Gall-stone, i. 1. 3. 8. Gangreen, ii. 1. 6. 17. Gargles, ii. 1. 3. 3. Gastritis, ii. 1. 2. 10. ---- superficialis, ii. 1. 3. 19. Genu tumor albus, i. 2. 3. 19. Gleet. See Gonorrhoea. Globus hystericus, i. 3. 1. 7. Gonorrhoea warm, i. 1. 2. 10. ---- cold, i. 2. 3. 8. Gout, iv. 1. 2. 15. iv. 2. 4. 9. ---- of the liver, ii. 1. 1. 7. ---- cases of, iv. 1. 2. 15. ---- cough, iv. 2. 1. 9. ---- of the stomach, i. 2. 4. 6. ---- hæmorrhage in, i. 1. 1. 4. Grace defined, iii. 1. 2. 4. Gravel distinguished from salts, i. 1. 3. 10. Gravitation, iv. 2. 4. Green-sickness. See Chlorosis. Grief, iii. 1. 2. 10. Gripes of children, i. 1. 2. 5. iv. 2. 1. 3. Gustus acrior, i. 1. 5. 4. ---- imminutus, i. 2. 5. 8. Gutta rosea, ii. 1. 4. 6. iv. 1. 2. 13. and 14. ---- serena, i. 2. 5. 5. H. Hæmorrhage arterial, i. 1. 1. 3. ---- of the lungs, i. 1. 1. 4. ---- of the nose, i. 1. 1. 5. ---- venous, i. 2. 1. 5. ---- of the rectum, i. 2. 1. 6. ---- of the kidnies, i. 2. 1. 7. ---- of the liver, i. 2. 1. 8. Hæmoptoe arterial, i. 1. 1. 4. ---- venous, i. 2. 1. 9. Hæmorrhois cruenta, i. 2. 1. 6. iv. 2. 4. 8. ---- alba, i. 1. 2. 12. Hair, grey, i. 2. 2. 11. ---- new, i. 1. 2. 15. ---- white by uterine pressure, Addit. i. Hallucination of sight, ii. 1. 7. 5. ---- of hearing, ii. 1. 7. 6. ---- maniacal, iii. 1. 2. 1. ---- studiosa, iii. 1. 2. 2. Harrogate water fact, i. 1. 4. 12. Head-ach. See Hemicrania and Cephalæa. Hearing acuter, i. 1. 5. 2. ---- diminished, i. 2. 5. 6. Heart-burn, i. 2. 4. 5. Heart stimulated, Suppl. i. 11. 7. i. 16. 9. Heat, animal, i. 1. 2. 1. i. 1. 2. 3. ---- sense of acuter, i. 1. 5. 6. ---- elemental, iv. 2. 4. ---- hectic lessened by swinging, iv. 2. 1. 10. ---- not perceived by the lungs, iii. 1. 1. 10. ---- not estimated by thermometers, Suppl. i. 7. ---- of the breath, Suppl. i. 2. 2. Hemicrania, iv. 2. 2. 8. iv. 2. 4. 3. ---- relieved by mercury, iv. 2. 2. 8. Hemiplegia, iii. 2. 1. 10. Hepatis tumor, i. 2. 3. 9. Hepatitis, ii. 1. 2. 12. ---- chronica, ii. 1. 4. 12. Herpes, ii. 1. 5. 8. ---- nephritica, iv. 1. 2. 11. Hiccough, ii. 1. 1. 6. iv. 1. 1. 7. Hip-joint injured, i. 2. 2. 17. Hoarseness, ii. 1. 3. 5. iii. 2. 1. 5. Horses, broken wind of, i. 2. 4. 9. Humectation of the body, iv. 1. 4. 7. Hunger, i. 2. 4. 2. Hydatides in calves, i. 2. 5. 4. Hydrocele, i. 2. 3. 11. Hydrocephalus inter, i. 2. 3. 12. i. 2. 5. 4. iii. 2. 1. 10. ---- from inflammation, Addit. ii. Hydrogene gas. Suppl. i. 9. 3. i. 11. 6. ---- in fevers, Suppl. i. 11. 6. i. 16. 9. Hydrothorax, i. 2. 3. 14. case of, iv. 2. 2. 13. Hydro-carbonate gas, Suppl. i. 9. 1. Suppl. i. 15. 3. Hydrops ovarii, i. 2. 3. 15. Hydrophobia, i. 3. 1. 11. iii. 1. 1. 15. iv. 1. 2. 7. Hypochondriasis, i. 2. 4. 10. Hysteralgia frigida, i. 2. 4. 17. Hysteria, i. 3. 1. 10. Suppl. i. 8. 11. ---- from fear, iv. 3. 1. 8. ---- from cold, iv. 3. 4. 3. ---- convulsions in, iii. 1. 1. 5. ---- laughter in, iii. 1. 1. 5. Hysteritis, ii. 1. 2. 16. I. Jactitatio, iii. 1. 1. 1. Jaundice, i. 1. 3. 8. i. 2. 4. 19. Icterus, i. 1. 3. 8. i. 2. 4. 19. Ileus, i. 3. 1. 6. ii. 1. 2. 11. Impotentia, ii. 2. 2. 3. Indigestion, i. 3. 1. 3. ---- See Anorexia and Apepsia. ---- from cold feet, iv. 2. 1. 6. Sup. i. 8. 5. Incubus, iii. 2. 1. 13. Infants, green stools of, i. 1. 2. 5. ---- new born, ii. 1. 1. 12. Inflammation of the eye, ii. 1. 2. 2. ---- superficial, ii. 1. 4. 1. ---- of the brain, ii. 1. 2. 3. ---- of the lungs, ii. 1. 2. 4. ---- superficial, ii. 1. 3. 7. ---- of the pleura, ii. 1. 2. 5. ---- of the diaphragm, ii. 1. 2. 6. ---- of the heart, ii. 1. 2. 7. ---- of the peritoneum, ii. 1. 2. 8. ---- of the mesentery, ii. 1. 2. 9. ---- of the stomach, ii. 1. 2. 10. ---- superficial, ii. 1. 3. 19. ---- of the bowels, ii. 1. 2. 11. ---- superficial, ii. 1. 3. 20. ---- of the liver, ii. 1. 2. 12. ---- chronical, ii. 1. 4. 12. ---- of the spleen, ii. 1. 2. 13. Sup. i. 16. 6. ---- of the kidnies, ii. 1. 2. 14. ---- of the bladder, ii. 1. 2. 15. ---- of the womb, ii. 1. 2. 16. ---- of the tonsils, ii. 1. 3. 3. ---- of the parotis, ii. 1. 3. 4. Inirritability of lacteals, i. 2. 3. 26. ---- of lymphatics, i. 2. 3. 27. ---- of the gall-bladder, i. 2. 4. 19. ---- of the kidney, i. 2. 4. 20. ---- of the spleen, Suppl. i. 16. 6. ---- vicissitudes of, i. 1. 1. Inoculation, ii. 1. 3. 9. Innutrition of bones, i. 2. 2. 14. Insanity, quick pulse in, iii. 1. 1. ---- from parturition, iii. 1. 2. ---- with fever, iii. 1. 2. ---- cure of, iii. 1. 2. ---- confinement in, iii. 1. 2. Insensibility, ii. 2. 1. 1. Ira, iii. 1. 2. 17. Ischias, ii. 1. 2. 18. i. 2. 4. 15. Issues, use of, i. 1. 2. 9. iii. 1. 1. 11. Itch, ii. 1. 5. 6. Itching, i. 1. 5. 9. ---- of the nose, iv. 2. 2. 6. L. Lacrymarum fluxus sym. iv. 1. 2. 1. Lameness of the hip, i. 2. 2. 17. Lassitude, iii. 2. 1. 1. Laughter, iv. 2. 3. 3. iii. 1. 1. 4. iv. 1. 3. 3. ---- See Risus. Leg, one shorter, i. 2. 2. 17. Lepra, ii. 1. 5. 3. Lethargus, iii. 2. 1. 14. Lethi timor, iii. 1. 2. 14. Lice, i. 1. 4. 15. Lientery, i. 2. 3. 6. Light debilitates in fevers, i. 2. 5. 3. Lingua arida, i. 1. 3. 1. iv. 2. 4. 11. Liver, torpor of, i. 2. 2. 6. ---- tumor of, i. 2. 3. 9. ---- inflamed, ii. 1. 2. 12. Lochia nimia, i. 2. 1. 13. Locked jaw, iii. 1. 1. 13. Love, sentimental, iii. 1. 2. 4. Lues venerea, ii. 1. 5. 2. ---- imaginaria, iii. 1. 2. 21. Lumbago, ii. 1. 2. 17. iii. 1. 1. 1. ---- cold, i. 2. 4. 16. Lumbricus, i. 1. 4. 10. Lunar influence on the solids, i. 2. 1. 11. Lungs, adhesions of, ii. 1. 2. 5. ---- not sensible to heat, iii. 1. 1. 10. Lusus digitorum invitus, iv. 1. 3. 4. M. Maculæ vultus, i. 2. 2. 10. Madness, mutable, iii. 1. 2. 1. Mammarum tumor, iv. 1. 2. 19. Mammularum tensio, iv. 1. 2. 6. i. 1. 4. 7. Mania mutabilis, iii. 1. 2. 1. Matter variolous, ii. 1. 3. 9. ---- contagious, ii. 1. 3. ii. 1. 6. 11. ---- inclosed, ii. 1. 6. 2. ---- oxygenated, ii. 1. 6. 6. ---- sanious, ii. 1. 6. 15. Measles, ii. 1. 3. 10. Membranes, what, iv. 1. 2. Menorrhagia, i. 2. 1. 11. Mercury crude, as a clyster, i. 3. 1. 6. ---- in all contagions, Suppl. i. 16. 7. ---- in vertigo, iv. 2. 1. 11. Miliaria, ii. 1. 3. 12. Milk new, for children, i. 1. 2. 5. ---- old, induces costiveness, ii. 2. 2. 7. Milk-crust, ii. 1. 5. 12. Miscarriage. See Abortion. Mæror, iii. 1. 2. 10. Mobility, iv. 1. 2. ---- of the skin, Suppl. i. 7. Mollities ossium, i. 2. 2. 14. Moon, effect of, iv. 2. 4. Morbilli. See Rubeola. Mortification, ii. 1. 6. 17. Morpiones, i. 1. 4. 14. Mucus diminished, i. 2. 2. 4. ---- of the throat cold, i. 2. 3. 1. ---- of the bowels, i. 2. 3. 6. i. 1. 2. 12. ---- of the lungs, i. 1. 3. 4. ---- forms stones, i. 1. 3. 9. ---- distinguished from pus, ii. 1. 6. 6. Mumps, ii. 1. 3. 4. Murmur aurium, iv. 2. 1. 15. Muscæ volitantes, i. 2. 5. 3. N. Nails, biting of, iv. 1. 3. 5. Nares aridi, i. 1. 3. 3. Nausea, dry, i. 2. 4. 3. ---- humid, i. 3. 2. 3. ---- ideal, iv. 3. 2. 1. ---- from conception, iv. 3. 2. 2. Navel-string of infants, ii. 1. 1. 12. ---- cut too soon, ii. 1. 1. 12. Neck thickens at puberty, iv. 1. 2. 7. Neck-swing, i. 2. 2. 16. Nephritis, ii. 1. 2. 14. i. 1. 3. 9. iii. 2. 1. 14. Nerves decussate, iii. 2. 1. 10. Nictitation irritative, i. 1. 4. 1. ---- sensitive, ii. 1. 1. 8. ---- involuntary, iv. 1. 3. 2. Night-mare, iii. 2. 1. 13. Nipples, tension of, i. 1. 4. 7. iv. 1. 2. 6. Nostalgia, iii. 1. 2. 6. Nostrils, dry, i. 1. 3. 3. O. Obesitas, i. 2. 3. 17. Odontitis, ii. 1. 4. 7. Odontalgia, i. 2. 4. 12. Oesophagi schirrus, i. 2. 3. 25. Olfactus acrior, i. 1. 5. 3. ---- imminutus, i. 2. 5. 7. Oil destroys insects, i. 1. 4. 14. ---- essential of animals, i. 1. 2. 14. ---- why injurious in erysipelas, ii. 1. 3. 2. Opium in catarrh, i. 2. 3. 3. ---- in diaphragmitis, ii. 1. 2. 6. Ophthalmy, internal, ii. 1. 2. 2. ---- superficial, ii. 1. 4. 1. Orci timor, iii. 1. 2. 15. Oscitatio, ii. 1. 1. 9. Ossium innutritio, i. 2. 2. 14. Otitis, ii. 1. 4. 8. Otalgia, i. 2. 4. 13. iv. 2. 2. 8. Otopuosis, ii. 1. 4. 8. Ovary, dropsy of, i. 2. 3. 15. ---- exsection of, i. 2. 3. 15. Oxygenation of blood, iv. 1. 4. 6. Oxygen gas, Suppl. i. 9. 3. ---- in fevers, Suppl. i. 11. 7. i. 16. 9. P. Pain exhausts sensorial power, iv. 2. 2. ---- greater prevents less, iv. 2. 2. 2. ---- nervous, i. 2. 4. ---- of the little finger, symptom, iv. 2. 2. 12. ---- of arm in hydrothorax, iv. 2. 2. 13. ---- of the bile-duct, iv. 2. 2. 4. ---- of the shoulder, iv. 2. 2. 9. ---- of the pharynx, iv. 2. 2. 5. ---- of the testis, iv. 2. 2. 11. ---- smarting, i. 1. 5. 10. ---- of the side, i. 2. 4. 14. iv. 1. 2. 16. ---- of menstruation, i. 2. 1. 12. ---- use of, iii. 1. 1. 11. i. 1. 2. 9. ---- of the uterus, i. 2. 4. 17. Paint, white, dangerous, ii. 1. 4. 6. Palate, defect of, i. 2. 2. 20. Paleness, i. 2. 2. 2. ---- from fear, iv. 3. 1. 5. ---- from sickness, iv. 2. 1. 4. ---- of urine after dinner, iv. 2. 1. 2. ---- from cold skin, iv. 2. 1. 1. Palpitation of heart, i. 3. 3. 2. i. 2. 1. 10. ---- from fear, iv. 3. 1. 6. ---- relieved by arsenic, iv. 2. 1. 18. Pancreas, torpor of, i. 2. 2. 7. Pandiculatio, ii. 1. 1. 9. Panting, ii. 1. 1. 4. i. 3. 3. 3. Paracentesis at the navel, i. 2. 3. 13. Paralysis, iii. 2. 1. 10. ---- of the bladder, iii. 2. 1. 6. ---- of the rectum, iii. 2. 1. 7. ---- of the hands, iii. 2. 1. 4. ---- cure of, iii. 2. 1. 4. Paraplegia, iii. 2. 1. 11. Paresis inirritativa, i. 2. 1. 2. Suppl. i. 8. 10. ---- sensitiva, ii. 2. 1. 3. ---- voluntaria, iii. 2. 1. 8. Paronychia internal, ii. 1. 2. 19. ---- superficial, ii. 1. 4. 5. Parturition, ii. 1. 1. 12. ii. 1. 2. 16. ---- more fatal in high life, ii. 1. 1. 12. ---- with convulsion, iii. 1. 1. iii. 1. 1. 7. Parotitis, ii. 1. 3. 4. Passions depressing and exciting, iv. 3. 1. 5. Paupertatis timor, iii. 1. 2. 13. Pediculus, i. 1. 4. 15. Pemphigus, ii. 1. 3. 14. Penetration of animal bodies, iv. 1. 4. 7. Peripneumony, ii. 1. 2. 4. ---- tracheal, ii. 1. 2. 4. ---- superficial, ii. 1. 3. 7. ---- inirritated, ii. 1. 2. 4. Peritonitis, ii. 1. 2. 8. Perspiration not an excrement, i. 1. 2. 14. ---- greatest in the hot fit, i. 1. 2. 3. ---- fetid, i. 1. 2. 14. Pertussis, ii. 1. 3. 8. Pestis, ii. 1. 3. 13. Petechiæ, i. 2. 1. 17. ---- cure of, Suppl. i. 2. 7. Pharynx, pain of, iv. 2. 2. 5. Phthisis, pulmonary, ii. 1. 6. 7. Pimples on the face, ii. 1. 4. 6. Piles, bleeding, i. 2. 1. 6. ---- white, i. 1. 2. 12. Placenta, ii. 1. 1. 12. ii. 1. 2. 16. Plague, ii. 1. 3. 13. Plasters, why moist, i. 1. 3. 6. Pleurisy, ii. 1. 2. 5. Pleurodyne chronica, i. 2. 4. 14. ---- rheumatica, iv. 1. 2. 16. Podagra, iv. 1. 2. 15. iv. 2. 4. 9. Polypus of the lungs, i. 1. 3. 4. ---- of the nose from worms, iv. 1. 2. 9. Pregnancy, ii. 1. 1. 12. Priapismus, i. 1. 4. 6. ii. 1. 7. 9. Proctalgia, i. 2. 4. 18. Prolapsus ani, i. 1. 4. 9. Pruritus, i. 1. 5. 9. ---- narium a vermibus, iv. 2. 2. 6. Psora, ii. 1. 5. 6. ---- imaginaria, iii. 1. 2. 22. Ptyalismus. See Salivatio. Pubis and throat sympathize, iv. 1. 2. 7. Puerperal fever, i. 2. 4. 9. ii. 1. 6. 16. Add. 8. ---- insanity, iii. 1. 2. 1. Pulchritudinis desiderium, iii. 1. 2. 12. Pullulation of trees, iv. 1. 4. 3. Pulse full, why, i. 1. 1. 1. ---- strong, how determined, i. 1. 1. 1. Suppl. i. 16. 10. ---- soft in vomiting, iv. 2. 1. 17. ---- intermittent, iv. 2. 1. 18. ---- quick from paucity of blood, Suppl. i. 11. 4. ---- quick sometimes in sleep, iii. 2. 1. 12. ---- quick in weak people, iii. 2. 1. Sup. i. 11. 4. ---- slower by swinging, iv. 2. 1. 10. ---- quick in chlorosis, i. 2. 3. 10. Punctæ mucosæ vultûs, i. 2. 2. 9. Purging. See Diarrhoea. Pus diminished, i. 2. 2. 3. ---- distinguished from mucus, ii. 1. 6. 6. R. Rabies, iii. 1. 2. 18. Rachitis, i. 2. 2. 15. Raucedo catarrhal, ii. 1. 3. 5. ---- paralytic, iii. 2. 1. 5. Recollection, loss of, iii. 2. 2. 1. Recti paralysis, iii. 2. 1. 7. ---- schirrus, i. 2. 3. 23. Red-gum, ii. 1. 3. 12. i. 1. 2. 3. Redness from heat, ii. 1. 7. 7. ---- of joy, ii. 1. 7. 8. ---- after dinner, iv. 1. 1. 1. ---- of anger, iv. 2. 3. 5. ---- of guilt, iv. 2. 3. 6. ---- of modesty, iv. 2. 3. 6. Respiration, ii. 1. 1. 2. ---- quick in exercise, ii. 1. 1. 4. ---- in softness of bones, i. 2. 2. 14. Restlessness, iii. 1. 1. 1. Reverie, iii. 1. 2. 2. iv. 2. 4. 2. Rhaphania, iii. 1. 1. 6. Rheumatism, iv. 1. 2. 16. ---- of the joints, iv. 1. 2. 16. ---- of the bowels, iv. 1. 2. 16. ---- of the pleura, iv. 1. 2. 16. ---- suppurating, iv. 1. 2. 16. ---- from sympathy, iv. 2. 2. 13. ---- chronical, i. 1. 3. 12. iii. 1. 1. 6. Rickets, i. 2. 2. 15. Ring-worm, ii. 1. 5. 10. Risus, iii. 1. 1. 4. iv. 2. 3. 3. ---- sardonicus, iv. 1. 2. 4. ---- invitus, iv. 1. 3. 3. Rubeola, ii. 1. 3. 10. Rubor a calore, ii. 1. 7. 7. ---- jucunditatis, ii. 1. 7. 8. ---- pransorum, iv. 1. 1. 1. Ructus, i. 3. 1. 2. Ruminatio, i. 3. 1. 1. iv. 3. 3. 1. S. Sailing in phthisis, ii. 1. 6. 7. Salivation warm, i. 1. 2. 6. ---- lymphatic, i. 3. 2. 2. ---- sympathetic, iv. 1. 2. 5. ---- in low fevers, i. 1. 2. 6. Salt of urine, i. 1. 2. 4. i. 1. 3. 9. Satyriasis, iii. 1. 2. 16. Scabies. See Psora. Scarlatina, ii. 1. 3. 11. Scarlet fever, ii. 1. 3. 11. Scald-head, ii. 1. 5. 11. Sciatica frigida, i. 2. 4. 15. Schirrus, i. 2. 3. 22. ---- suppurans, ii. 1. 4. 15. ---- of the rectum, i. 2. 3. 23. ---- of the urethra, i. 2. 3. 24. ---- of the oesophagus, i. 2. 3. 25. Scorbutus, i. 2. 1. 15. ---- suppurans, ii. 1. 4. 14. Scrophula, i. 2. 3. 21. ---- suppurating, ii. 1. 4. 14. ---- produces insanity, iii. 1. 2. Scurvy, i. 2. 1. 15. ---- suppurating, ii. 1. 4. 14. Scurf of the head, i. 1. 3. 6. ---- of the tongue, i. 1. 3. 1. Sea air in phthisis, ii. 1. 6. 7. Seat, descent of, i. 1. 4. 9. Seed, ejection of, ii. 1. 1. 11. Sea-sickness, iv. 2. 1. 10. Suppl. i. 8. 3. See-saw of old people, iii. 2. 1. 2. Sensitive association, law of, iv. 2. 2. 2. Sensation inert, Suppl. i. 6. 4. Setons, ii. 1. 6. 6. Shingles, ii. 1. 5. 9. Shoulder, pain of, iv. 2. 2. 9. Shrieking, iii. 1. 1. 3. Sickness, i. 2. 4. 4. i. 3. 2. 3. ---- cured by a blister, iv. 1. 1. 3. ---- by warm skin, iv. 1. 1. 2. Suppl. i. 11. 4. ---- by whirling, i. 1. 1. 4. ---- by swinging, Suppl. i. 15. 3. ---- by hydrocarbonate gas, Suppl. i. 15. 3. ---- See Nausea. Sight acuter, i. 1. 5. 1. ---- impaired, i. 2. 5. 2. Side, chronical pain of, i. 2. 4. 14. Sighing and sobbing, iii. 1. 2. 10. Sitis calida, i. 2. 4. 1. ---- frigida, i. 2. 4. 1. ---- defectus, ii. 2. 2. 2. Skin pale in old age, i. 2. 2. 2. ---- from cold, i. 2. 2. 2. ---- dry, i. 1. 3. 6. ---- yellowish, i. 2. 2. 2. ---- bluish and shrunk, i. 2. 1. 1. ---- reddish, ii. 1. 3. 1. ---- cold after meals, iv. 2. 1. 1. Sleep, iii. 2. 1. 12. ---- interrupted, i. 2. 1. 3. ---- periods in, iv. 2. 4. 1. ---- with quick pulse, iii. 2. 1. 12. ---- disturbed by digestion, iii. 2. 1. 12. Sleep-walkers, iii. 1. 1. 9. Small-pox, ii. 1. 3. 9. ---- why distinct and confluent, Sup. i. 15. 2. ---- secondary fever of, ii. 1. 6. 12. ---- eruption of, iv. 1. 2. 12. Smarting, i. 1. 5. 10. Smell acuter, i. 1. 5. 3. ---- impaired, i. 2. 5. 7. Sneezing, ii. 1. 1. 3. iv. 1. 2. 2. Snow in scrophula, i. 2. 3. 21. ---- in paralysis, iii. 2. 1. 4. Snuff in hydrocephalus, i. 2. 3. 12. Somnambulism, iii. 1. 1. 9. Somnium, ii. 1. 7. 4. Somnus, iii. 2. 1. 12. iv. 2. 4. 1. ---- interruptus, i. 2. 1. 3. Softness of bones, i. 2. 2. 14. Spasm of diaphragm, iii. 1. 1. 11. ---- of the heart, iii. 1. 1. 11. Spine distorted, i. 2. 2. 16. ---- protuberant, i. 2. 2. 18. ---- bifid, i. 2. 2. 19. Spitting blood, i. 1. 1. 4. i. 2. 1. 9. Spleen swelled, i. 2. 3. 18. Suppl. i. 16. 6. Splenitis, ii. 1. 2. 13. Spots on the face, i. 2. 2. 9. Spots seen on bed-clothes, i. 2. 5. 3. Squinting, i. 2. 5. 4. ---- in hydrocephalus, i. 2. 5. 4. Stammering, iv. 2. 3. 1. Stays tight, injurious, ii. 1. 1. 12. Sterility, ii. 2. 2. 4. Sternutatio, ii. 1. 1. 3. iv. 1. 2. 2. ---- a lumine, iv. 1. 2. 2. Stimulants, their twofold effect, ii. 1. 2. 6. Stocks for children dangerous, i. 2. 2. 17. Stomach, torpor of, Suppl. i. 10. i. 16. 6. ---- inflammation of, ii. 1. 2. 10. ii. 1. 3. 19. ---- its association, iv. 1. 1. ---- cause of fever, Suppl. i. 8. 8. Stones in the bladder, See Calculi. ---- in horses, i. 1. 3. 5. i. 1. 3. 10. Strabismus, i. 2. 5. 4. Strangury, ii. 1. 1. 11. iv. 2. 2. 2. ---- convulsive, iv. 2. 2. 3. Strength and debility metaphors, i. 2. 1. Stridor dentium, iii. 1. 1. 12. Studium inane, iii. 1. 2. 2. iv. 2. 4. 2. Stultitia inirritabilis, i. 2. 5. 1. ---- insensibilis, ii. 2. 1. 1. ---- voluntaria, iii. 2. 2. 2. Stupor, i. 2. 5. 10. Suppl. i. 15. Subsultus tendinum, iii. 1. 1. 5. Sudor. See Sweats. Suggestion, slow, Surprise, i. 1. 5. 11. Sweats, warm, i. 1. 2. 3. ---- cold, i. 2. 3. 2. ---- lymphatic, i. 3. 2. 7. ---- asthmatic, i. 3. 2. 8. iv. 3. 1. 2. ---- covered in bed, iv. 1. 1. 2. Suppl. i. 11. 6 ---- in fever fits, why, i. 1. 2. 5. ---- from exercise, i. 1. 2. 3. ---- from heat, i. 1. 2. 3. ---- from medicines, i. 1. 2. 3. Sweaty hands cured, i. 3. 2. 7. Swinging, ii. 1. 6. 7. ---- makes the pulse slower, iv. 2. 1. 10. Swing centrifugal, Suppl. i. 15 and 3. Sympathy direct and reverse, iv. 1. 1. f. ---- with others, iii. 1. 2. 24. ---- of various parts, Suppl. i. 11. 5. ---- reverse of lacteals and lymphatics, Suppl. i. 11. 5 ---- of capillaries, Suppl. i. 11. 5. ---- direct of stomach and heart, Sup. i. 11. 5. ---- of throat and pubis, iv. 1. 2. 7. Syncope, i. 2. 1. 4. ---- epileptic, iii. 2. 1. 15. Syngultus, ii. 1. 1. 6. ---- nephriticus, iv. 1. 1. 7. Syphilis, ii. 1. 5. 2. ---- imaginaria, iii. 1. 2. 21. Syphon capillary of cloth, ii. 1. 3. 1. T. Tactus acrior, i. 1. 5. 5. ---- imminutus, i. 2. 5. 6. Tape-worm, i. 1. 4. 11. Tapping at the navel, i. 2. 3. 13. Taste. See Gustus. ---- bitter, not from bile, i. 1. 3. 1. Tædium vitæ, ii. 2. 1. 2. Tænia, i. 1. 4. 11. Tears sympathetic, iv. 1. 2. 1. iii. 1. 2. 10. Teeth, to preserve, i. 1. 4. 5. ---- fall out whole, ii. 1. 4. 7. Tenesmus, ii. 1. 1. 10. ---- calculosus, iv. 1. 2. 8. Testium dolor nephriticus, iv. 2. 2. 11. ---- tumor in gonorrhoea, iv. 1. 2. 18. ---- tumor in parotitide, iv. 1. 2. 19. Tetanus trismus, iii. 1. 1. 13. ---- doloroficus, iii. 1. 1. 14. Thirst. See Sitis and Adipsia. Thread-worm, i. 1. 4. 12. Throat swelled, i. 2. 3. 20. ---- thickens at puberty, iv. 2. 1. 7. ---- grown up, i. 2. 3. 25. Thrush, ii. 1. 3. 17. Tickling, i. 1. 5. 8. Timor orci, iii. 1. 2. 15. ---- lethi, iii. 1. 2. 14. ---- paupertatis, iii. 1. 2. 13. Tinea, ii. 1. 5. 11. Tinnitus aurium, iv. 2. 1. 15. Titillatio, i. 1. 5. 8. Titubatio linguæ, iv. 2. 3. 1. Tobacco, smoke of in piles, i. 2. 1. 6. Tongue dry, i. 1. 3. 1. Suppl. i. 2. ---- coloured mucus, i. 1. 3. 1. Tonsillitis, ii. 1. 3. 3. Tonsils swelled from bad teeth, i. 2. 3. 21. ii. 1. 3. 3. Torpor of the liver, i. 2. 2. 6. ---- of the pancreas, i. 2. 2. 7. ---- of the lungs, Suppl. 1. 9. ---- of the stomach, Suppl. i. 10. ---- of the heart, Suppl. i. 10. Tooth-ach, i. 2. 4. 12. ii. 1. 4. 7. Tooth-edge, iv. 1. 2. 3. Toothing, i. 1. 4. 5. Tooth-powder, i. 1. 4. 5. Touch. See Tactus. ---- deceived three ways, i. 2. 5. 9. iv. 2. 1. 10. Transfusion of blood, i. 2. 3. 25. Suppl. i. 14. 4. Translation of matter, i. 3. 2. 9. ---- of milk, i. 3. 2. 10. ---- of urine, i. 3. 2. 11. Transparency of cornea, i. 1. 4. 1. ---- of crystalline, i. 2. 2. 13. ---- of air before rain, i. 1. 4. 1. Tremor of old age, iii. 2. 1. 3. ---- of fever, iii. 1. 1. 2. ---- of anger, iv. 2. 3. 4. ---- of fear, iv. 3. 1. 5. Tussis ebriorum, ii. 1. 1. 5. ---- convulsiva, ii. 1. 3. 8. ---- hepatica, iv. 2. 1. 8. ---- arthritica, iv. 2. 1. 9. ---- periodica, iv. 3. 4. 2. ---- a pedibus frigidis, iv. 2. 1. 7. Tympany, i. 2. 4. 9. U. Ulcers, healing of, i. 1. 3. 13. ---- of the cornea, i. 1. 3. 14. ---- from burns, i. 1. 3. 13. ---- scrophulous, ii. 1. 4. 13. ---- of the throat, ii. 1. 3. 3. ii. 1. 3. 11. ---- of the legs, ii. 1. 4. 14. Unguium morsiuncula, iv. 1. 3. 5. Urethra, scirrhus of, i. 2. 3. 24. ---- fistula of, ii. 1. 4. 11. Urine copious, coloured, i. 1. 2. 4. ---- copious, pale, i. 2. 3. 5. ---- diminished, coloured, i. 1. 3. 7. ---- diminished, pale, i. 2. 2. 5. ---- its mucus, salts, Prussian blue, i. 1. 2. 4. ---- why less and coloured in dropsies, i. 1. 3. 7. ---- translation of, i. 3. 2. 11. ---- difficulty of, iii. 2. 1. 6. ---- not secreted, i. 2. 2. 8. ---- pale after meals, iv. 2. 1. 2. ---- pale from cold skin, iv. 2. 1. 3. ---- sediment in fevers, Suppl. i. 2. 3. ---- pale in fevers, Suppl. i. 2. 3. and 5. Urticaria, ii. 1. 3. 16. Uteri descensus, i. 1. 4. 8. V. Vacillatio senilis, iii. 2. 1. 2. Varicella, ii. 1. 3. 15. Variola, ii. 1. 3. 9. ---- eruption of, iv. 1. 2. 12. Vasorum capil retrogressio, i. 3. 3. 1. Venereal orgasm, iv. 1. 4. 4. ---- disease, ii. 1. 5. 2. ---- imaginary, iii. 1. 2. 21. Ventriculi ægritudo, i. 2. 4. 4. ---- vesicatorio sanata, iv. 1. 1. 3. Vermes, i. 1. 4. 10. Vertigo rotatory, iv. 2. 1. 10. ---- of sight, iv. 2. 1. 11. ---- inebriate, iv. 2. 1. 12. ---- of fever, iv. 2. 1. 13. ---- from the brain, iv. 2. 1. 14. ---- of the ears, iv. 2. 1. 15. ---- of the touch, Addit. iii. ---- of the touch, taste and smell, iv. 2. 1. 16. ---- with vomiting, iv. 3. 2. 3. ---- produces slow pulse, iv. 2. 1. 10. ---- of blind men, iv. 2. 1. 10. ---- use of mercurials in it, iv. 2. 1. 11. ---- from ideas, Addit. iii. Vibices, i. 2. 1. 16. Suppl. i. 2. 7. Vigilia, iii. 1. 2. 3. iv. 1. 3. 6. Vision acuter, i. 1. 5. 1. ---- diminished, i. 2. 5. 2. ---- expends much sensorial power, i. 2. 5. 3. Vita ovi, iv. 1. 4. 1. ---- hiemi-dormientium, iv. 1. 4. 2. Vitus's dance, iv. 2. 3. 2. Volition, three degrees of, iii. 2. 1. 12. ---- lessens fever, iii. 2. 1. 12. Suppl. i. 11. 6. ---- produces fever, iii. 2. 1. 12. ---- without deliberation, iv. 1. 3. 2. Addit. iv. Vomica, ii. 1. 6. 3. Vomitus, i. 3. 1. 4. Vomendi conamen inane, i. 3. 1. 8. Vomiting stopped, iv. 1. 1. 3. iv. 1. 1. f. ---- voluntary, iv. 3. 3. 2. ---- how acquired, iv. 1. 1. 2. ---- vertiginous, iv. 3. 2. 3. ---- from stone in ureter, iv. 3. 2. 4. ---- from paralytic stroke, iv. 3. 2. 5. ---- from tickling the throat, iv. 3. 2. 6. ---- sympathizes with the skin, iv. 3. 2. 7. ---- in hæmoptoe, i. 1. 1. 4. ---- from defect of association, iv. 2. 1. 10. Vulnerum cicatrix, i. 1. 3. 13. W. Watchfulness, iii. 1. 2. 3. iv. 1. 3. 6. Water-qualm, i. 3. 1. 3. Weakness, three kinds of, i. 2. 1. Whirling-chair, Suppl. i. 15. 3. Whirling-bed, Suppl. i. 15. 7. White swelling of the knee, i. 2. 3. 19. Winking, ii. 1. 1. 8. i. 1. 4. 1. iv. 1. 3. 2. Wine in fevers, ii. 1. 3. 1. iv. 2. 1. 12. Winter-sleeping animals, iv. 1. 4. 2. Witlow, superficial, ii. 1. 4. 5. ---- internal, ii. 1. 2. 19. Womb, descent of, i. 1. 4. 8. ---- inflammation of, ii. 1. 2. 16. Worms, i. 1. 4. 10. ---- mucus counterfeits, i. 1. 3. 4. ---- in sheep, i. 2. 3. 9. Wounds, healing of, i. 1. 3. 13. Y. Yawning, ii. 1. 1. 9. Yaws, ii. 1. 5. 5. Z. Zona ignea, ii. 1. 5. 9. iv. 1. 2. 11. ii. 1. 2. 14. * * * * * ZOONOMIA; OR, THE LAWS OF ORGANIC LIFE. PART III. CONTAINING THE ARTICLES OF THE MATERIA MEDICA, WITH AN ACCOUNT OF THE OPERATION OF MEDICINES. * * * * * IN VIVUM CORPUS AGUNT MEDICAMENTA. * * * * * PREFACE. THE MATERIA MEDICA includes all those substances, which may contribute to the restoration of health. These may be conveniently distributed under seven articles according to the diversity of their operations. 1. NUTRIENTIA, or those things which preserve in their natural state the due exertions of all the irritative motions. 2. INCITANTIA, or those things which increase the exertions of all the irritative motions. 3. SECERNENTIA, or those things which increase the irritative motions, which constitute secretion. 4. SORBENTIA, or those things which increase the irritative motions, which constitute absorption. 5. INVERTENTIA, or those things which invert the natural order of the successive irritative motions. 6. REVERTENTIA, or those things which restore the natural order of the inverted irritative motions. 7. TORPENTIA, those things which diminish the exertions of all the irritative motions. It is necessary to apprize the reader, that in the following account of the virtues of Medicines their usual doses are always supposed to be exhibited; and the patient to be exposed to the degree of exterior heat, which he has been accustomed to, (where the contrary is not mentioned), as any variation of either of these circumstances varies their effects. * * * * * ARTICLES OF THE MATERIA MEDICA. * * * * * ART. I. NUTRIENTIA. I. 1. Those things, which preserve in their natural state the due exertions of all the irritative motions, are termed nutrientia; they produce the growth, and restore the waste, of the system. These consist of a variety of mild vegetable and animal substances, water, and air. 2. Where stronger stimuli have been long used, they become necessary for this purpose, as mustard, spice, salt, beer, wine, vinegar, alcohol, opium. Which however, as they are unnatural stimuli, and difficult to manage in respect to quantity, are liable to shorten the span of human life, sooner rendering the system incapable of being stimulated into action by the nutrientia. See Sect XXXVII. 4. On the same account life is shorter in warmer climates than in more temperate ones. II. OBSERVATIONS ON THE NUTRIENTIA. I. 1. The flesh of animals contains more nourishment, and stimulates our absorbent and secerning vessels more powerfully, than the vegetable productions, which we use as food; for the carnivorous animals can fast longer without injury than the graminivorous; and we feel ourselves warmer and stronger after a meal of flesh than of grain. Hence in diseases attended with cold extremities and general debility this kind of diet is preferred; as in rickets, dropsy, scrophula, and in hysteric and hypochondriac cases, and to prevent the returns of agues. Might not flesh in small quantities bruised to a pulp be more advantageously used in fevers attended with debility than vegetable diet? That flesh, which is of the darkest colour, generally contains more nourishment, and stimulates our vessels more powerfully, than the white kinds. The flesh of the carnivorous and piscivorous animals is so stimulating, that it seldom enters into the food of European nations, except the swine, the Soland goose (Pelicanus Bassanus), and formerly the swan. Of these the swine and the swan are fed previously upon vegetable aliment; and the Soland goose is taken in very small quantity, only as a whet to the appetite. Next to these are the birds, that feed upon insects, which are perhaps the most stimulating and the most nutritive of our usual food. It is said that a greater quantity of volatile alkali can be obtained from this kind of flesh, to which has been ascribed its stimulating quality. But it is more probable, that fresh flesh contains only the elements of volatile alkali. 2. Next to the dark coloured flesh of animals, the various tribes of shell-fish seem to claim their place, and the wholesome kinds of mushrooms, which must be esteemed animal food, both for their alkalescent tendency, their stimulating quality, and the quantity of nourishment, which they afford; as oysters, lobsters, crabfish, shrimps; mushrooms; to which perhaps might be added some of the fish without scales; as the eel, barbolt, tench, smelt, turbot, turtle. The flesh of many kinds of fish, when it is supposed to have undergone a beginning putrefaction, becomes luminous in the dark. This seems to shew a tendency in the phosphorus to escape, and combine with the oxygen of the atmosphere; and would hence shew, that this kind of flesh is not so perfectly animalized as those before mentioned. This light, as it is frequently seen on rotten wood, and sometimes on veal, which has been kept too long, as I have been told, is commonly supposed to have its cause from putrefaction; but is nevertheless most probably of phosphoric origin, like that seen in the dark on oyster-shells, which have previously been ignited, and afterwards exposed to the sunshine, and on the Bolognian stone. See Botan. Gard. Vol. I. Cant. I. line 1 and 2, the note. 3. The flesh of young animals, as of lamb, veal, and sucking pigs, supplies us with a still less stimulating food. The broth of these is said to become sour, and continues so a considerable time before it changes into putridity; so much does their flesh partake of the chemical properties of the milk, with which these animals are nourished. 4. The white meats, as of turkey, partridge, pheasant, fowl, with their eggs, seem to be the next in mildness; and hence are generally first allowed to convalescents from inflammatory diseases. 5. Next to those should be ranked the white river-fish, which have scales, as pike, perch, gudgeon. II. 1. Milk unites the animal with the vegetable source of our nourishment, partaking of the properties of both. As it contains sugar, and will therefore ferment and produce a kind of wine or spirit, which is a common liquor in Siberia; or will run into an acid by simple agitation, as in the churning of cream; and lastly, as it contains coagulable lymph, which will undergo the process of putrefaction like other animal substances, as in old cheese. 2. Milk may be separated by rest or by agitation into cream, butter, butter-milk, whey, curd. The cream is easier of digestion to adults, because it contains less of the coagulum or cheesy part, and is also more nutritive. Butter consisting of oil between an animal and vegetable kind contains still more nutriment, and in its recent state is not difficult of digestion if taken in moderate quantity. See Art. I. 2. 3. 2. Butter-milk if it be not bitter is an agreeable and nutritive fluid, if it be bitter it has some putrid parts of the cream in it, which had been kept too long; but is perhaps not less wholesome for being sour to a certain degree: as the inferior people in Scotland choose sour milk in preference to skimmed milk before it is become sour. Whey is the least nutritive and easiest of digestion. And in the spring of the year, when the cows feed on young grass, it contains so much of vegetable properties, as to become a salutary potation, when drank to about a pint every morning to those, who during the winter have taken too little vegetable nourishment, and who are thence liable to bilious concretions. 3. Cheese is of various kinds, according to the greater or less quantity of cream, which it contains, and according to its age. Those cheeses, which are easiest broken to pieces in the mouth, are generally easiest of digestion, and contain most nutriment. Some kinds of cheese, though slow of digestion, are also slow in changing by chemical processes in the stomach, and therefore will frequently agree well with those, who have a weak digestion; as I have seen toasted cheese vomited up a whole day after it was eaten without having undergone any apparent change, or given any uneasiness to the patient. It is probable a portion of sugar, or of animal fat, or of the gravy of boiled or roasted meat, mixed with cheese at the time of making it, might add to its pleasant and nutritious quality. 4. The reason, why autumnal milk is so much thicker or coagulable than vernal milk, is not easy to understand, but as new milk is in many respects similar to chyle, it may be considered as food already in part digested by the animal it is taken from, and thence supplies a nutriment of easy digestion. But as it requires to be curdled by the gastric acid, before it can enter the lacteals, as is seen in the stomachs of calves, it seems more suitable to children, whose stomachs abound more with acidity, than to adults; but nevertheless supplies good nourishment to many of the latter, and particularly to those, who use vegetable food, and whose stomachs have not been much accustomed to the unnatural stimulus of spice, salt, and spirit. See Class I. 1. 2. 5. III. 1. The seeds, roots, leaves, and fruits of plants, constitute the greatest part of the food of mankind; the respective quantities of nourishment, which these contain, may perhaps be estimated from the quantity of starch, or of sugar, they can be made to produce: in farinaceous seeds, the mucilage seems gradually to be converted into starch, while they remain in our granaries; and the starch by the germination of the young plant, as in making malt from barley, or by animal digestion, is converted into sugar. Hence old wheat and beans contain more starch than new; and in our stomachs other vegetable and animal materials are converted into sugar; which constitutes in all creatures a part of their chyle. Hence it is probable, that sugar is the most nutritive part of vegetables; and that they are more nutritive, as they are convertible in greater quantity into sugar by the power of digestion; as appears from sugar being found in the chyle of all animals, and from its existing in great quantity in the urine of patients in the diabætes, of which a curious case is related in Sect. XXIX. 4. where a man labouring under this malady eat and drank an enormous quantity, and sometimes voided sixteen pints of water in a day, with an ounce of sugar in each pint. 2. Oil, when mixed with mucilage or coagulable lymph, as in cream or new milk, is easy of digestion, and constitutes probably the most nutritive part of animal diet; as oil is another part of the chyle of all animals. As these two materials, sugar and butter, contain much nutriment under a small volume, and readily undergo some chemical change so as to become acid or rancid; they are liable to disturb weak stomachs, when taken in large quantity, more than aliment, which contains less nourishment, and is at the same time less liable to chemical changes; because the chyle is produced quicker than the torpid lacteals can absorb it, and thence undergoes a further chemical process. Sugar and butter therefore are not so easily digested, when taken in large quantity, as those things, which contain less nutriment; hence, where the stomach is weak, they must be used in less quantity. But the custom of some people in restraining children entirely from them, is depriving them of a very wholesome, agreeable, and substantial part of their diet. Honey, manna, sap-juice, are different kinds of less pure sugar. 3. All the esculent vegetables contain a bland oil, or mucilage, or starch, or sugar, or acid; and, as their stimulus is moderate, are properly given alone as food in inflammatory diseases; and mixed with milk constitute the food of thousands. Other vegetables possess various degrees and various kinds of stimulus; and to these we are beholden for the greater part of our Materia Medica, which produce nausea, sickness, vomiting, catharsis, intoxication, inflammation, and even death, if unskilfully administered. The acrid or intoxicating, and other kinds of vegetable juices, such as produce sickness, or evacuate the bowels, or such even as are only disagreeable to the palate, appear to be a part of the defence of those vegetables, which possess them, from the assaults of larger animals or of insects. As mentioned in the Botanic Garden, Part II. Cant. I. line 161, note. This appears in a forcible manner from the perusal of some travels, which have been published of those unfortunate people, who have suffered shipwreck on uncultivated countries, and have with difficulty found food to subsist, in otherwise not inhospitable climates. 4. As these acrid and intoxicating juices generally reside in the mucilage, and not in the starch of many roots, and seeds, according to the observation of M. Parmentier, the wholesome or nutritive parts of some vegetables may be thus separated from the medicinal parts of them. Thus if the root of white briony be rasped into cold water, by means of a bread-grater made of a tinned iron plate, and agitated in it, the acrid juice of the root along with the mucilage will be dissolved, or swim, in the water; while a starch perfectly wholesome and nutritious will subside, and may be used as food in times of scarcity. M. Parmentier further observes, that potatoes contain too much mucilage in proportion to their starch, which prevents them from being converted into good bread. But that if the starch be collected from ten pounds of raw potatoes by grating them into cold water, and agitating them, as above mentioned; and if the starch thus procured be mixed with other ten pounds of boiled potatoes, and properly subjected to fermentation like wheat flour, that it will make as good bread as the finest wheat. Good bread may also be made by mixing wheat-flour with boiled potatoes. Eighteen pounds of wheat flour are said to make twenty-two pounds and a half of bread. Eighteen pounds of wheat-flour mixed with nine pounds of boiled potatoes, are said to make twenty-nine pounds and a half of bread. This difference of weight must arise from the difference of the previous dryness of the two materials. The potatoes might probably make better flour, if they were boiled in steam, in a close vessel, made some degrees hotter than common boiling water. Other vegetable matters may be deprived of their too great acrimony by boiling in water, as the great variety of the cabbage, the young tops of white briony, water-cresses, asparagus, with innumerable roots, and some fruits. Other plants have their acrid juices or bitter particles diminished by covering them from the light by what is termed blanching them, as the stems and leaves of cellery, endive, sea-kale. The former method either extracts or decomposes the acrid particles, and the latter prevents them from being formed. See Botanic Garden, Vol. I. additional note XXXIV. on the Etiolation of vegetables. 5. The art of cookery, by exposing vegetable and animal substances to heat, has contributed to increase the quantity of the food of mankind by other means besides that of destroying their acrimony. One of these is by converting the acerb juices of some fruits into sugar, as in the baking of unripe pears, and the bruising of unripe apples; in both which situations the life of the vegetable is destroyed, and the conversion of the harsh juice into a sweet one must be performed by a chemical process; and not by a vegetable one only, as the germination of barley in making malt has generally been supposed. Some circumstances, which seem to injure the life of several fruits, seem to forward the saccharine process of their juices. Thus if some kinds of pears are gathered a week before they would ripen on the tree, and are laid on a heap and covered, their juice becomes sweet many days sooner. The taking off a circular piece of the bark from a branch of a pear-tree causes the fruit of that branch to ripen sooner by a fortnight, as I have more than once observed. The wounds made in apples by insects occasion those apples to ripen sooner; caprification, or the piercing of figs, in the island of Malta, is said to ripen them sooner; and I am well informed, that when bunches of grapes in this country have acquired their expected size, that if the stalk of each bunch be cut half through, that they will sooner ripen. The germinating barley in the malt-house I believe acquires little sweetness, till the life of the seed is destroyed, and the saccharine process then continued or advanced by the heat in drying it. Thus in animal digestion, the sugar produced in the stomach is absorbed by the lacteals as fast as it is made, otherwise it ferments, and produces flatulency; so in the germination of barley in the malt-house, so long as the new plant lives, the sugar, I suppose, is absorbed as fast as it is made; but that, which we use in making beer, is the sugar produced by a chemical process after the death of the young plant, or which is made more expeditiously, than the plant can absorb it. It is probably this saccharine process, which obtains in new hay-stacks too hastily, and which by immediately running into fermentation produces so much heat as to set them on fire. The greatest part of the grain, or seeds, or roots, used in the distilleries, as wheat, canary seed, potatoes, are not I believe previously subjected to germination, but are in part by a chemical process converted into sugar, and immediately subjected to vinous fermentation; and it is probable a process may sometime be discovered of producing sugar from starch or meal; and of separating it from them for domestic purposes by alcohol, which dissolves sugar but not mucilage; or by other means. Another method of increasing the nutriment of mankind by cookery, is by dissolving cartilages and bones, and tendons, and probably some vegetables, in steam or water at a much higher degree of heat than that of boiling. This is to be done in a close vessel, which is called Papin's digester; in which, it is said, that water may be made red-hot, and will then dissolve all animal substances; and might thus add to our quantity of food in times of scarcity. This vessel should be made of iron, and should have an oval opening at top, with an oval lid of iron larger than the aperture; this lid should be slipped in endways, when the vessel is filled, and then turned, and raised by a screw above it into contact with the under edges of the aperture. There should also be a small tube or hole covered with a weighted valve to prevent the danger of bursting the digester. Where the powers of digestion are weakened, broths made by boiling animal and vegetable substances in water afford a nutriment; though I suppose not so great as the flesh and vegetables would afford, if taken in their solid form, and mixed with saliva in the act of mastication. The aliment thus prepared should be boiled but a short time, nor should be suffered to continue in our common kitchen-utensils afterwards, as they are lined with a mixture of half lead and half tin, and are therefore unwholesome, though the copper is completely covered. And those soups, which have any acid or wine boiled in them, unless they be made in silver, or in china, or in those pot-vessels, which are not glazed by the addition of lead, are truly poisonous; as the acid, as lemon-juice or vinegar, when made hot, erodes or dissolves the lead and tin lining of the copper-vessels, and the leaden glaze of the porcelain ones. Hence, where silver cannot be had, iron vessels are preferable to tinned copper ones; or those made of tinned iron-plates in the common tin-shops, which are said to be covered with pure or block tin. 6. Another circumstance, which facilitates the nourishment of mankind, is the mechanic art of grinding farinaceous seeds into powder between mill-stones; which may be called the artificial teeth of society. It is probable, that some soft kinds of wood, especially when they have undergone a kind of fermentation, and become of looser texture, might be thus used as food in times of famine. Nor is it improbable, that hay, which has been kept in stacks, so as to undergo the saccharine process, may be so managed by grinding and by fermentation with yeast like bread, as to serve in part for the sustenance of mankind in times of great scarcity. Dr. Priestley gave to a cow for some time a strong infusion of hay in large quantity for her drink, and found that she produced during this treatment above double the quantity of milk. Hence if bread cannot be made from ground hay, there is great reason to suspect, that a nutritive beverage may be thus prepared either in its saccharine state, or fermented into a kind of beer. In times of great scarcity there are other vegetables, which though not in common use, would most probably afford wholesome nourishment, either by boiling them, or drying and grinding them, or by both those processes in succession. Of these are perhaps the tops and the bark of all those vegetables, which are armed with thorns or prickles, as gooseberry trees, holly, gorse, and perhaps hawthorn. The inner bark of the elm tree makes a kind of gruel. And the roots of fern, and probably of very many other roots, as of grass and of clover taken up in winter, might yield nourishment either by boiling or baking, and separating the fibres from the pulp by beating them; or by getting only the starch from those, which possess an acrid mucilage, as the white briony. 7. However the arts of cookery and of grinding may increase or facilitate the nourishment of mankind, the great source of it is from agriculture. In the savage state, where men live solely by hunting, I was informed by Dr. Franklin, that there was seldom more than one family existed in a circle of five miles diameter; which in a state of pasturage would support some hundred people, and in a state of agriculture many thousands. The art of feeding mankind on so small a grain as wheat, which seems to have been discovered in Egypt by the immortal name of Ceres, shewed greater ingenuity than feeding them with the large roots of potatoes, which seem to have been a discovery of ill-fated Mexico. This greater production of food by agriculture than by pasturage, shews that a nation nourished by animal food will be less numerous than if nourished by vegetable; and the former will therefore be liable, if they are engaged in war, to be conquered by the latter, as Abel was slain by Cain. This is perhaps the only valid argument against inclosing open arable fields. The great production of human nourishment by agriculture and pasturage evinces the advantage of society over the savage state; as the number of mankind becomes increased a thousand fold by the arts of agriculture and pasturage; and their happiness is probably under good governments improved in as great a proportion, as they become liberated from the hourly fear of beasts of prey, from the daily fear of famine, and of the occasional incursions of their cannibal neighbours. But pasturage cannot exist without property both in the soil, and the herds which it nurtures; and for the invention of arts, and production of tools necessary to agriculture, some must think, and others labour; and as the efforts of some will be crowned with greater success than that of others, an inequality of the ranks of society must succeed; but this inequality of mankind in the present state of the world is too great for the purposes of producing the greatest quantity of human nourishment, and the greatest sum of human happiness; there should be no slavery at one end of the chain of society, and no despotism at the other.--By the future improvements of human reason such governments may possibly hereafter be established, as may a hundred-fold increase the numbers of mankind, and a thousand-fold their happiness. IV. 1. Water must be considered as a part of our nutriment, because so much of it enters the composition of our solids as well as of our fluids; and because vegetables are now believed to draw almost the whole of their nourishment from this source. As in them the water is decomposed, as it is perspired by them in the sunshine, the oxygen gas increases the quantity and the purity of the atmosphere in their vicinity, and the hydrogen seems to be retained, and to form the nutritive juices, and consequent secretions of rosin, gum, wax, honey, oil, and other vegetable productions. See Botanic Garden, Part I. Cant. IV. line 25, note. It has however other uses in the system, besides that of a nourishing material, as it dilutes our fluids, and lubricates our solids; and on all these accounts a daily supply of it is required. 2. River-water is in general purer than spring-water; as the neutral salts washed down from the earth decompose each other, except perhaps the marine salt; and the earths, with which spring-water frequently abounds, is precipitated; yet it is not improbable, that the calcareous earth dissolved in the water of many springs may contribute to our nourishment, as the water from springs, which contain earth, is said to conduce to enrich those lands, which are flooded with it, more than river water. 3. Many arguments seem to shew, that calcareous earth contributes to the nourishment of animals and vegetables. First because calcareous earth constitutes a considerable part of them, and must therefore either be received from without, or formed by them, or both, as milk, when taken as food by a lactescent woman, is decomposed in the stomach by the process of digestion, and again in part converted into milk by the pectoral glands. Secondly, because from the analogy of all organic life, whatever has composed a part of a vegetable or animal may again after its chemical solution become a part of another vegetable or animal, such is the general transmigration of matter. And thirdly, because the great use of lime in agriculture on almost all kinds of soil and situation cannot be satisfactorily explained from its chemical properties alone. Though these may also in certain soils and situations have considerable effect. The chemical uses of lime in agriculture may be, 1. from its destroying in a short time the cohesion of dead vegetable fibres, and thus reducing them to earth, which otherwise is effected by a slow process either by the consumption of insects or by a gradual putrefaction. Thus I am informed that a mixture of lime with oak bark, after the tanner has extracted from it whatever is soluble in water, will in two or three months reduce it to a fine black earth, which, if only laid in heaps, would require as many years to effect by its own spontaneous fermentation or putrefaction. This effect of lime must be particularly advantageous to newly inclosed commons when first broken up. Secondly, lime for many months continues to attract moisture from the air or earth, which it deprives I suppose of carbonic acid, and then suffers it to exhale again, as is seen on the plastered walls of new houses. On this account it must be advantageous when mixed with dry or sandy soils, as it attracts moisture from the air above or the earth beneath, and this moisture is then absorbed by the lymphatics of the roots of vegetables. Thirdly, by mixing lime with clays it is believed to make them less cohesive, and thus to admit of their being more easily penetrated by vegetable fibres. A mixture of lime with clays destroys their superabundancy of acid, if such exists, and by uniting with it converts it into gypsum or alabaster. And lastly, fresh lime destroys worms, snails, and other insects, with which it happens to come in contact. Yet do not all these chemical properties seem to account for the great uses of lime in almost all soils and situations, as it contributes so much to the melioration of the crops, as well as to their increase in quantity. Wheat from land well limed is believed by farmers, millers, and bakers, to be, as they suppose, thinner skinned; that is, it turns out more and better flour; which I suppose is owing to its containing more starch and less mucilage. In respect to grass-ground I am informed, that if a spadeful of lime be thrown on a tussock, which horses or cattle have refused to touch for years, they will for many succeeding seasons eat it quite close to the ground. One property of lime is not perhaps yet well understood, I mean its producing so much heat, when it is mixed with water; which may be owing to the elementary fluid of heat consolidated in the lime. It is the steam occasioned by this heat, when water is sprinkled upon lime, if the water be not in too great quantity or too cold, which breaks the lime into such fine powder as almost to become fluid, which cannot be effected perhaps by any other means, and which I suppose must give great preference to lime in agriculture, and to the solutions of calcareous earth in water, over chalk or powdered limestone, when spread upon the land. 4. It was formerly believed that waters replete with calcareous earth, such as incrust the inside of tea-kettles, or are laid to petrify moss, were liable to produce or to increase the stone in the bladder. This mistaken idea has lately been exploded by the improved chemistry, as no calcareous earth, or a very minute quantity, was found in the calculi analysed by Scheel and Bergman. The waters of Matlock and of Carlsbad, both which cover the moss, which they pass through, with a calcareous crust, are so far from increasing the stone of the bladder or kidnies, that those of Carlsbad are celebrated for giving relief to those labouring under these diseases. Philos. Trans. Those of Matlock are drank in great quantities without any suspicion of injury; and I well know a person who for above ten years has drank about two pints a day of cold water from a spring, which very much incrusts the vessels, it is boiled in, with calcareous earth, and affords a copious calcareous sediment with a solution of salt of tartar, and who enjoys a state of uninterrupted health. V. 1. As animal bodies consist much both of oxygen and azote, which make up the composition of atmospheric air, these should be counted amongst nutritious substances. Besides that by the experiments of Dr. Priestley it appears, that the oxygen gains admittance into the blood through the moist membranes of the lungs; and seems to be of much more immediate consequence to the preservation of our lives than the other kinds of nutriment above specified. As the basis of fixed air, or carbonic acid gas, is carbone, which also constitutes a great part both of vegetable and animal bodies; this air should likewise be reckoned amongst nutritive substances. Add to this, that when this carbonic acid air is swallowed, as it escapes from beer or cyder, or when water is charged with it as detruded from limestone by vitriolic acid, it affords an agreeable sensation both to the palate and stomach, and is therefore probably nutritive. The immense quantity of carbone and of oxygen which constitute so great a part of the limestone countries is almost beyond conception, and, as it has been formed by animals, may again become a part of them, as well as the calcareous matter with which they are united. Whence it may be conceived, that the waters, which abound with limestone in solution, may supply nutriment both to animals and to vegetables, as mentioned above. VI. 1. The manner, in which nutritious particles are substituted in the place of those, which are mechanically abraded, or chemically decomposed, or which vanish by animal absorption, must be owing to animal appetency, as described in Sect. XXXVII. 3. and is probably similar to the process of inflammation, which produces new vessels and new fluids; or to that which constitutes the growth of the body to maturity. Thus the granulations of new flesh to repair the injuries of wounds are visible to the eye; as well as the callous matter, which cements broken bones; the calcareous matter, which repairs injured snail-shells; and the threads, which are formed by silk-worms and spiders; which are all secreted in a softer state, and harden by exsiccation, or by the contact of the air, or by absorption of their more fluid parts. Whether the materials, which thus supply the waste of the system, can be given any other way than by the stomach, so as to preserve the body for a length of time, is worth our inquiry; as cases sometimes occur, in which food cannot be introduced into the stomach, as in obstructions of the oesophagus, inflammations of the throat, or in hydrophobia; and other cases are not unfrequent in which the power of digestion is nearly or totally destroyed, as in anorexia epileptica, and in many fevers. In the former of these circumstances liquid nutriment may sometimes be got into the stomach through a flexible catheter; as described in Class III. 1. 1. 15. In the latter many kinds of mild aliment, as milk or broth, have frequently been injected as clysters, together with a small quantity of opium, as ten drops of the tincture, three or four times a day; to which also might be added very small quantities of vinous spirit. But these, as far as I have observed, will not long sustain a person, who cannot take any sustenance by the stomach. 2. Another mode of applying nutritive fluids might be by extensive fomentations, or by immerging the whole body in a bath of broth, or of warm milk, which might at the same time be coagulated by rennet, or the acid of the calf's stomach; broth or whey might thus probably be introduced, in part at least, into the circulation, as a solution of nitre is said to have been absorbed in a pediluvium, which was afterwards discovered by the manner in which paper dipped frequently in the urine of the patient and dried, burnt and sparkled like touch-paper. Great quantity of water is also known to be absorbed by those, who have bathed in the warm bath after exercise and abstinence from liquids. Cleopatra was said to travel with 4000 milch-asses in her train, and to bathe every morning in their milk, which she probably might use as a cosmetic rather than a nutritive. 3. The transfusion of blood from another animal into the vein of one, who could take no sustenance by the throat, or digest none by the stomach, might long continue to support him; and perhaps other nutriment, as milk or mucilage, might be this way introduced into the system, but we have not yet sufficient experiments on this subject. See Sect. XXXII. 4. and Class I. 2. 3. 25. and Sup. I. 14. 2. VII. Various kinds of condiments, or sauces, have been taken along with vegetable or animal food, and have been thought by some to strengthen the process of digestion and consequent process of nutrition. Of these wine, or other fermented liquors, vinegar, salt, spices, and mustard, have been in most common use, and I believe to the injury of thousands. As the stomach by their violent stimulus at length loses its natural degree of irritability, and indigestion is the consequence; which is attended with flatulency and emaciation. Where any of these have been taken so long as to induce a habit, they must either be continued, but not increased; or the use of them should be gradually and cautiously diminished or discontinued, as directed in Sect. XII. 7. 8. III. CATALOGUE OF THE NUTRIENTIA. I. 1. Venison, beef, mutton, hare, goose, duck, woodcock, snipe, moor-game. 2. Oysters, lobsters, crabs, shrimps, mushrooms, eel, tench, barbolt, smelt, turbot, sole, turtle. 3. Lamb, veal, sucking-pig. 4. Turkey, partridge, pheasant, fowl, eggs. 5. Pike, perch, gudgeon, trout, grayling. II. Milk, cream, butter, buttermilk, whey, cheese. III. Wheat, barley, oats, peas, potatoes, turnips, carrots, cabbage, asparagus, artichoke, spinach, beet, apple, pear, plum, apricot, nectarine, peach, strawberry, grape, orange, melon, cucumber, dried figs, raisins, sugar, honey. With a great variety of other roots, seeds, leaves, and fruits. IV. Water, river-water, spring-water, calcareous earth. V. Air, oxygene, azote, carbonic acid gas. VI. Nutritive baths and clysters, transfusion of blood. VII. Condiments. * * * * * ART. II. INCITANTIA. I. 1. Those things, which increase the exertions of all the irritative motions, are termed incitantia. As alcohol, or the spirituous part of fermented liquors, opium, and many drugs, which are still esteemed poisons, their proper doses not being ascertained. To these should be added the exhilarating passions of the mind, as joy, love: and externally the application of heat, electricity, æther, essential oils, friction, and exercise. 2. These promote both the secretions and absorptions, increase the natural heat, and remove those pains, which originate from the defect of irritative motions, termed nervous pains; and prevent the convulsions consequent to them. When given internally they induce costiveness, and deep coloured urine; and by a greater dose intoxication, and its consequences. II. OBSERVATIONS ON THE INCITANTIA. I. 1. Opium and alcohol increase all the secretions and absorptions. The increase of the secretion of sensorial power appears from the violent exertions of drunken people; the secretion of sweat is more certainly excited by opium or wine than by any other medicine; and the increase of general heat, which these drugs produce, is an evidence of their effect in promoting all the secretions; since an increase of secretion is always attended with increase of heat in the part, as in hepatic and other inflammations. 2. But as they at the same time promote absorption; those fluids, which are secreted into receptacles, as the urine, bile, intestinal and pulmonary mucus, have again their thinner parts absorbed; and hence, though the quantity of secreted fluid was increased, yet as the absorption was also increased, the excretion from these receptacles is lessened; at the same time that it is deeper coloured or of thicker consistence, as the urine, alvine feces, and pulmonary mucus. Whereas the perspiration being secreted on the surface of the body is visible in its increased quantity, before it can be reabsorbed; whence arises that erroneous opinion, that opium increases the cutaneous secretion, and lessens all the others. 3. It must however be noted, that after evacuations opium seems to promote the absorptions more than the secretions; if you except that of the sensorial power in the brain, which probably suffers no absorption. Hence its efficacy in restraining hæmorrhages, after the vessels are emptied, by promoting venous absorption. 4. In ulcers the matter is thickened by the exhibition of opium from the increased absorption of the thinner parts of it; but it is probable, that the whole secretion, including the part which is absorbed, is increased; and hence new fibres are secreted along with the matter, and the ulcer fills with new granulations of flesh. But as no ulcer can heal, till it ceases to discharge; that is, till the absorption becomes as great as the excretion; those medicines, which promote absorption only, are more advantageous for the healing an ulcer after it is filled with new flesh; as the Peruvian bark internally; with bandages and solutions of lead externally. 5. There are many pains which originate from a want of due motion in the part, as those occasioned by cold; and all those pains which are attended with cold extremities, and are generally termed nervous. These are relieved by whatever excites the part into its proper actions, and hence by opium and alcohol; which are the most universal stimulants we are acquainted with. In these cases the effect of opium is produced, as soon as the body becomes generally warm; and a degree of intoxication or sleep follows the cessation of the pain. These nervous pains (as they are called) frequently return at certain periods of time, and are also frequently succeeded by convulsions; in these cases if opium removes the pain, the convulsions do not come on. For this purpose it is best to exhibit it gradually, as a grain every hour, or half hour, till it intoxicates. Here it must be noted, that a much less quantity will prevent the periods of these cold pains, than is necessary to relieve them after their access. As a grain and half of opium given an hour before the expected paroxysm will prevent the cold fit of an intermittent fever, but will not soon remove it, when it is already formed. For in the former case the usual or healthy associations or catenations of motion favour the effect of the medicine; in the latter case these associations or catenations are disordered, or interrupted, and new ones are formed, which so far counteract the effect of the medicine. When opium has been required in large doses to ease or prevent convulsions, some have advised the patient to omit the use of wine, as a greater quantity of opium might then be exhibited; and as opium seems to increase absorption more, and secretion less, than vinous spirit; it may in some cases be useful to exchange one for the other; as in diseases attended with too great evacuation, as diarrhoea, and dysentery, opium may be preferable; on the contrary in tetanus, or locked-jaw, where inflammation of the system might be of service, wine may be preferable to opium; see Class III. 1. 1. 13. I have generally observed, that a mixture of spirit of wine and warm water, given alternately with the doses of opium, has soonest and most certainly produced that degree of intoxication, which was necessary to relieve the patient in the epilepsia dolorifica. 6. There is likewise some relief given by opium to inflammatory pains, or those from excess of motion in the affected part; but with this difference, that this relief from the pains, and the sleep, which it occasions, does not occur till some hours after the exhibition of the opium. This requires to be explained; after the stimulus of opium or of alcohol ceases, as after common drunkenness, a consequent torpor comes on; and the whole habit becomes less irritable by the natural stimuli. Hence the head-achs, sickness, and languor, on the next day after intoxication, with cold skin, and general debility. Now in pains from excess of motion, called inflammatory pains, when opium is given, the pain is not relieved, till the debility comes on after the stimulus ceases to act; for then after the greater stimulus of the opium has exhausted much of the sensorial power; the less stimulus, which before caused the pain, does not now excite the part into unnatural action. In these cases the stimulus of the opium first increases the pain; and it sometimes happens, that so great a torpor follows, as to produce the death or mortification of the affected part; whence the danger of giving opium in inflammatory diseases, especially in inflammation of the bowels; but in general the pain returns with its former violence, when the torpor above mentioned ceases. Hence these pains attended with inflammation are best relieved by copious venesection, other evacuations, and the class of medicines called torpentia. 7. These pains from excess of motion are attended with increased heat of the whole, or of the affected part, and a strong quick pulse; the pains from defect of motion are attended with cold extremities, and a weak pulse; which is also generally more frequent than natural, but not always so. 8. Opium and alcohol are the only two drugs, we are much acquainted with, which intoxicate; and by this circumstance are easily distinguished from the secernentia and sorbentia. Camphor, and cicuta, and nicotiana, are thought to induce a kind of intoxication; and there are many other drugs of this class, whose effects are less known, or their doses not ascertained; as atropa belladonna, hyocyamus, stramonium, prunus laurocerasus, menispermum, cynoglossum, some fungi, and the water distilled from black cherry-stones; the last of which was once much in use for the convulsions of children, and was said to have good effect; but is now improvidently left out of our pharmacopias. I have known one leaf of the laurocerasus, shred and made into tea, given every morning for a week with no ill consequence to a weak hysteric lady, but rather perhaps with advantage. 9. The pernicious effects of a continued use of much vinous spirit is daily seen and lamented by physicians; not only early debility, like premature age, but a dreadful catalogue of diseases is induced by this kind of intemperance; as dropsy, gout, leprosy, epilepsy, insanity, as described in Botanic Garden, Part II. Canto III. line 357. The stronger or less diluted the spirit is taken, the sooner it seems to destroy, as in dram-drinkers; but still sooner, when kernels of apricots, or bitter almonds, or laurel-leaf, are infused in the spirit, which is termed ratafia; as then two poisons are swallowed at the same time. And vinegar, as it contains much vinous spirit, is probably a noxious part of our diet. And the distilled vinegar, which is commonly sold in the shops, is truly poisonous, as it is generally distilled by means of a pewter or leaden alembic-head or worm-tube, and abounds with lead; which any one may detect by mixing with it a solution of liver of sulphur. Opium, when taken as a luxury, not as a medicine, is as pernicious as alcohol; as Baron de Tott relates in his account of the opium-eaters in Turkey. 10. It must be observed, that a frequent repetition of the use of this class of medicines so habituates the body to their stimulus, that their dose may gradually be increased to an astonishing quantity, such as otherwise would instantly destroy life; as is frequently seen in those, who accustom themselves to the daily use of alcohol and opium; and it would seem, that these unfortunate people become diseased as soon as they omit their usual potations; and that the consequent gout, dropsy, palsy, or pimpled face, occur from the debility occasioned from the want of accustomed stimulus, or to some change in the contractile fibres, which requires the continuance or increase of it. Whence the cautions necessary to be observed are mentioned in Sect. XII. 7. 8. 11. It is probable, that some of the articles in the subsequent catalogue do not induce intoxication, though they have been esteemed to do so; as tobacco, hemlock, nux vomica, stavisagria; and on this account should rather belong to other arrangements, as to the secernentia, or sorbentia, or invertentia. II. 1. Externally the application of heat, as the warm bath, by its stimulus on the skin excites the excretory ducts of the perspirative glands, and the mouths of the lymphatics, which open on its surface, into greater action; and in consequence many other irritative motions, which are associated with them. To this increased action is added pleasurable sensation, which adds further activity to the system; and thus many kinds of pain receive relief from this additional atmosphere of heat. The use of a warm bath of about 96 or 98 degrees of heat, for half an hour once a day for three or four months, I have known of great service to weak people, and is perhaps the least noxious of all unnatural stimuli; which however, like all other great excitement, may be carried to excess, as complained of by the ancients. The unmeaning application of the words relaxation and bracing to warm and cold baths has much prevented the use of this grateful stimulus; and the misuse of the term warm-bath, when applied to baths colder than the body, as to those of Buxton and Matlock, and to artificial baths of less than 90 degrees of heat, which ought to be termed cold ones, has contributed to mislead the unwary in their application. The stimulus of wine, or spice, or salt, increases the heat of the system by increasing all or some of the secretions; and hence the strength is diminished afterwards by the loss of fluids, as well as by the increased action of the fibres. But the stimulus of the warm-bath supplies heat rather than produces it; and rather fills the system by increased absorption, than empties it by increased secretion; and may hence be employed with advantage in almost all cases of debility with cold extremities, perhaps even in anasarca, and at the approach of death in fevers. In these cases a bath much beneath 98 degrees, as of 80 or 85, might do injury, as being a cold-bath compared with the heat of the body, though such a bath is generally called a warm one. The activity of the system thus produced by a bath of 98 degrees of heat, or upwards, does not seem to render the patients liable to take cold, when they come out of it; for the system is less inclined to become torpid than before, as the warmth thus acquired by communication, rather than by increased action, continues long without any consequent chillness. Which accords with the observation of Dr. Fordyce, mentioned in Sup. I. 5. 1. who says, that those who are confined some time in an atmosphere of 120 or 130 degrees of heat, do not feel cold or look pale on coming into a temperature of 30 or 40 degrees; which would produce great paleness and sensation of coldness in those, who had been some time confined in an atmosphere of only 86 or 90 degrees of heat. Treatise on Simple Fever, p. 168. Hence heat, where it can be confined on a torpid part along with moisture, as on a scrophulous tumour, will contribute to produce suppuration or resolution. This is done by applying a warm poultice, which should be frequently repeated; or a plaster of resin, wax, or fat; or by covering the part with oiled silk; both which last prevent the perspirable matter from escaping as well as the heat of the part, as these substances repel moisture, and are bad conductors of heat. Another great use of the stimulus of heat is by applying it to torpid ulcers, which are generally termed scrophulous or scorbutic, and are much easier inclined to heal, when covered with several folds of flannel. Mr. ---- had for many months been afflicted with an ulcer in perinæo, which communicated with the urethra, through which a part of his urine was daily evacuated with considerable pain; and was reduced to a great degree of debility. He used a hot-bath of 96 or 98 degrees of heat every day for half an hour during about six months. By this agreeable stimulus repeated thus at uniform times not only the ulcer healed, contrary to the expectation of his friends, but he acquired greater health and strength, than he had for some years previously experienced. Mrs. ---- was affected with transient pains, which were called nervous spasms, and with great fear of diseases, which she did not labour under, with cold extremities, and general debility. She used a hot-bath every other day of 96 degrees of heat for about four months, and recovered a good state of health, with greater strength and courage, than she had possessed for many months before. Mr. Z. a gentleman about 65 years of age, who had lived rather intemperately in respect to vinous potation, and had for many years had annual visits of the gout, which now became irregular, and he appeared to be losing his strength, and beginning to feel the effects of age. He used a bath, as hot as was agreeable to his sensations, twice a week for about a year and half, and greatly recovered his health and strength with less frequent and less violent returns of regular gout, and is now near 80 years of age. When Dr. Franklin, the American philosopher, was in England many years ago, I recommended to him the use of a warm-bath twice a week to prevent the too speedy access of old age, which he then thought that he felt the approach of, and I have been informed, that he continued the use of it till near his death, which was at an advanced age. All these patients were advised not to keep themselves warmer than their usual habits, after they came out of the bath, whether they went into bed or not; as the design was not to promote perspiration, which weakens all constitutions, and seldom is of service to any. Thus a flannel shirt, particularly if it be worn in warm weather, occasions weakness by stimulating the skin by its points into too great action, and producing heat in consequence; and occasions emaciation by increasing the discharge of perspirable matter; and in both these respects differs from the effect of warm bathing, which communicates heat to the system at the same time that it stimulates it, and causes absorption more than exhalation. 2. The effect of the passage of an electric shock through a paralytic limb in causing it to contract, besides the late experiments of Galvani and Volta on frogs, intitle it to be classed amongst universal stimulants. Electric shocks frequently repeated daily for a week or two remove chronical pains, as the pleurodyne chronica, Class I. 2. 4. 14. and other chronic pains, which are termed rheumatic, probably by promoting the absorption of some extravasated material. Scrophulous tumours are sometimes absorbed, and sometimes brought to suppurate by passing electric shocks through them daily for two or three weeks. [Illustration] Miss ----, a young lady about eight years of age, had a swelling about the size of a pigeon's egg on her neck a little below her ear, which long continued in an indolent state. Thirty or forty small electric shocks were passed through it once or twice a day for two or three weeks, and it then suppurated and healed without difficulty. For this operation the coated jar of the electric machine had on its top an electrometer, which measured the shocks by the approach of a brass knob, which communicated with the external coating to another, which communicated with the internal one, and their distance was adjusted by a screw. So that the shocks were so small as not to alarm the child, and the accumulated electricity was frequently discharged, as the wheel continued turning. The tumour was inclosed between two other brass knobs, which were fixed on wires, which passed through glass tubes, the tubes were cemented in two grooves on a board, so that at one end they were nearer each other than at the other, and the knobs were pushed out so far as exactly to include the tumour, as described in the annexed plate, which is about half the size of the original apparatus. Inflammations of the eyes without fever are frequently cured by taking a stream of very small electric sparks from them, or giving the electric sparks to them, once or twice a day for a week or two; that is, the new vessels, which constitute inflammation in these inirritable constitutions, are absorbed by the activity of the absorbents induced by the stimulus of the electric aura. For this operation the easiest method is to fix a pointed wire to a stick of sealing wax, or to an insulating handle of glass, one end of this wire communicates with the prime conductor, and the point is approached near the inflamed eye in every direction. III. Externally the application of ether, and of essential oils, as of cloves or cinnamon, seem to possess a general stimulating effect. As they instantly relieve tooth-ach, and hiccough, when these pains are not in violent degree; and camphor in large doses is said to produce intoxication; this effect however I have not been witness to, and have reason to doubt. The manner in which ether and the essential oil operate on the system when applied externally, is a curious question, as pain is so immediately relieved by them, that they must seem to penetrate by the great fluidity or expansive property of a part of them, as of their odoriferous exhalation or vapour, and that they thus stimulate the torpid part, and not by their being taken up by the absorbent vessels, and carried thither by the long course of circulation; nor is it probable, that these pains are relieved by the sympathy of the torpid membrane with the external skin, which is thus stimulated into action; as it does not succeed, unless it is applied over the pained part. Thus there appears to be three different modes by which extraneous bodies may be introduced into the system, besides that of absorption. 1st. By ethereal transition, as heat and electricity; 2d. by chemical attraction, as oxygen; and 3d. by expansive vapour, as ether and essential oils. IV. The perpetual necessity of the mixture of oxygen gas with the blood in the lungs evinces, that it must act as a stimulus to the sanguiferous system, as the motions of the heart and arteries presently cease, when animals are immersed in airs which possess no oxygen. It may also subsequently answer another important purpose, as it probably affords the material for the production of the sensorial power; which is supposed to be secreted in the brain or medullary part of the nerves; and that the perpetual demand of this fluid in respiration is occasioned by the sensorial power, which is supposed to be produced from it, being too subtle to be long confined in any part of the system. Another proof of the stimulant quality of oxygen appears from the increased acrimony, which the matter of a common abscess possesses, after it has been exposed to the air of the atmosphere, but not before; and probably all other contagious matters owe their fever-producing property to having been converted into acids by their union with oxygen. As oxygen penetrates the fine moist membranes of the air-vessels of the lungs, and unites with the blood by a chemical attraction, as is seen to happen, when blood is drawn into a bason, the lower surface of the crassamentum is of a very dark red so long as it is covered from the air by the upper surface, but becomes florid in a short time on its being exposed to the atmosphere; the manner of its introduction into the system is not probably by animal absorption but by chemical attraction, in which circumstance it differs from the fluids before mentioned both of heat and electricity, and of ether and essential oils. As oxygen has the property of passing through moist animal membranes, as first discovered by the great Dr. Priestley, it is probable it might be of use in vibices, and petechiæ in fevers, and in other bruises; if the skin over those parts was kept moist by warm water, and covered with oxygen gas by means of an inverted glass, or even by exposing the parts thus moistened to the atmosphere, as the dark coloured extravasated blood might thus become florid, and by its increase of stimulus facilitate its reabsorption. Two weak patients, to whom I gave oxygen gas in as pure a state as it can easily be procured from Exeter manganese, and in the quantity of about four gallons a day, seemed to feel refreshed, and stronger, and to look better immediately after respiring it, and gained strength in a short time. Two others, one of whom laboured under confirmed hydrothorax, and the other under a permanent and uniform difficulty of respiration, were not refreshed, or in any way served by the use of oxygen in the above quantity of four gallons a day for a fortnight, which I ascribed to the inirritability of the diseased lungs. For other cases the reader is referred to the publications of Dr. Beddoes; Confederations on the Use of Factitious Airs, sold by Johnson, London. Its effects would probably have been greater in respect to the quantity breathed, if it had been given in a dilute state, mixed with 10 or 20 times its quantity of atmospheric air, as otherwise much of it returns by expiration without being deprived of its quality, as may be seen by the person breathing on the flame of a candle, which it enlarges. See the Treatise of Dr. Beddoes above mentioned. V. Those passions, which are attended with pleasurable sensation, excite the system into increased action in consequence of that sensation, as joy, and love, as is seen by the flush of the skin. Those passions, which are attended with disagreeable sensation, produce torpor in general by the expence of sensorial power occasioned by inactive pain; unless volition be excited in consequence of the painful sensation; and in that case an increased activity of the system occurs; thus paleness and coldness are the consequence of fear, but warmth and redness are the consequence of anger. VI. Besides the exertions of the system occasioned by increased stimuli, and consequent irritation, and by the passions of the mind above described, the increased actions occasioned by exercise belong to this article. These may be divided into the actions of the body in consequence of volition, which is generally termed labour; or secondly, in consequence of agreeable sensation, which is termed play or sport; thirdly, the exercise occasioned by agitation, as in a carriage or on horseback; fourthly, that of friction, as with a brush or hand, so much used in the baths of Turkey; and lastly, the exercise of swinging. The first of these modes of exercise is frequently carried to great excess even amongst our own labourers, and more so under the lash of slavery; so that the body becomes emaciated and sinks under either the present hardships, or by a premature old age. The second mode of exercise is seen in the play of all young animals, as kittens, and puppies, and children; and is so necessary to their health as well as to their pleasure, that those children, which are too much confined from it, not only become pale-faced and bloated, with tumid bellies, and consequent worms, but are liable to get habits of unnatural actions, as twitching of their limbs, or of some parts of their countenance; together with an ill-humoured or discontented mind. Agitation in a carriage or on horseback, as it requires some little voluntary exertion to preserve the body perpendicular, but much less voluntary exertion than in walking, seems the best adapted to invalids; who by these means obtain exercise principally by the strength of the horse, and do not therefore too much exhaust their own sensorial power. The use of friction with a brush or hand, for half an hour or longer morning and evening, is still better adapted to those, who are reduced to extreme debility; and none of their own sensorial power is thus expended, and affords somewhat like the warm-bath activity without self-exertion, and is used as a luxury after warm bathing in many parts of Asia. Another kind of exercise is that of swinging, which requires some exertion to keep the body perpendicular, or pointing towards the center of the swing, but is at the same time attended with a degree of vertigo; and is described in Class II. 1. 6. 7. IV. 2. 1. 10. Sup. I. 3. and 15. The necessity of much exercise has perhaps been more insisted upon by physicians, than nature seems to demand. Few animals exercise themselves so as to induce visible sweat, unless urged to it by mankind, or by fear, or hunger. And numbers of people in our market towns, of ladies particularly, with small fortunes, live to old age in health, without any kind of exercise of body, or much activity of mind. In summer weak people cannot continue too long in the air, if it can be done without fatigue; and in winter they should go out several times in a day for a few minutes, using the cold air like a cold-bath, to invigorate and render them more hardy. III. CATALOGUE OF THE INCITANTIA. I. Papaver somniferum; poppy, opium. Alcohol, wine, beer, cyder. Prunus lauro-cerasus; laurel, distilled water from the leaves. Prunus cerasus; black cherry, distilled water from the kernels. Nicotiana tabacum; tobacco? the essential oil, decoction of the leaf. Atropa belladona; deadly nightshade, the berries. Datura stramoneum; thorn-apple, the fruit boiled in milk. Hyoscyamus reticulatus; henbane, the seeds and leaves. Cynoglossum; hounds tongue. Menispermum, cocculus; Indian berry. Amygdalus amarus; bitter almond. Cicuta; hemlock. Conium maculatum? Strychnos nux vomica? Delphinium stavisagria? II. Externally, heat, electricity. III. Ether, essential oils. IV. Oxygen gas. V. Passions of love, joy, anger. VI. Labour, play, agitation, friction. * * * * * ART. III. SECERNENTIA. I. Those things which increase the irritative motions, which constitute secretion, are termed secernentia; which are as various as the glands, which they stimulate into action. 1. Diaphoretics, as aromatic vegetables, essential oils, ether, volatile alcali, neutral salts, antimonial preparations, external heat, exercise, friction, cold water for a time with subsequent warmth, blisters, electric fluid. 2. Sialagogues, as mercury internally, and pyrethrum externally. 3. Expectorants, as squill, onions, gum ammoniac, seneka root, mucilage: some of these increase the pulmonary perspiration, and perhaps the pulmonary mucus. 4. Diuretics, as neutral salts, fixed alcali, balsams, resins, asparagus, cantharides. 5. Cathartics of the mild kind, as sena, jalap, neutral salts, manna. They increase the secretions of bile, pancreatic juice, and intestinal mucus. 6. The mucus of the bladder is increased by cantharides, and perhaps by oil of turpentine. 7. The mucus of the rectum by aloe internally, by clysters and suppositories externally. 8. The mucus of the cellular membrane is increased by blisters and sinapisms. 9. The mucus of the nostrils is increased by errhines of the milder kind, as marum, common snuff. 10. The secretion of tears is increased by volatile salts, the vapour of onions, by grief, and joy. 11. All those medicines increase the heat of the body, and remove those pains, which originate from a defect of motion in the vessels, which perform secretion; as pepper produces a glow on the skin, and balsam of Peru is said to relieve the flatulent cholic. But these medicines differ from the preceding class, as they neither induce costiveness nor deep coloured urine in their usual dose, nor intoxication in any dose. 12. Yet if any of these are used unnecessarily, it is obvious, like the incitantia, that they must contribute to shorten our lives by sooner rendering peculiar parts of the system disobedient to their natural stimuli. Of those in daily use the great excess of common salt is probably the most pernicious, as it enters all our cookery, and is probably one cause of scrophula, and of sea-scurvy, when joined with other causes of debility. See Botanic Garden, Part II. Canto IV. line 221. Spices taken to excess by stimulating the stomach, and the vessels of the skin by association, into unnecessary action, contribute to weaken these parts of the system, but are probably less noxious than the general use of so much salt. II. OBSERVATIONS ON THE SECERNENTIA. I. 1. Some of the medicines of this class produce absorption in some degree, though their principal effect is exerted on the secerning part of our system. We shall have occasion to observe a similar circumstance in the next class of medicines termed Sorbentia; as of these some exert their effects in a smaller degree on the secerning system. Nor will this surprise any one, who has observed, that all natural objects are presented to us in a state of combination; and that hence the materials, which produce these different effects, are frequently found mingled in the same vegetable. Thus the pure aromatics increase the action of the vessels, which secrete the perspirable matter; and the pure astringents increase the action of the vessels, which absorb the mucus from the lungs, and other cavities of the body; hence it must happen, that nutmeg, which possesses both these qualities, should have the double effect above mentioned. Other drugs have this double effect, and belong either to the class of Secernentia or Sorbentia, according to the dose in which they are exhibited. Thus a small dose of alum increases absorption, and induces costiveness; and a large one increases the secretions into the intestinal canal, and becomes cathartic. And this accounts for the constipation of the belly left after the purgative quality of rhubarb ceases, for it increases absorption in a smaller dose, and secretion in a greater. Hence when a part of the larger dose is carried out of the habit by stools, the small quantity which remains induces costiveness. Hence rhubarb exhibited in small doses, as 2 or 3 grains twice a day, strengthens the system by increasing the action of the absorbent vessels, and of the intestinal canal. 2. Diaphoretics. The perspiration is a secretion from the blood in its passage through the capillary vessels, as other secretions are produced in the termination of the arteries in the various glands. After this secretion the blood loses its florid colour, which it regains in its passage through the lungs; which evinces that something besides water is secreted on the skins of animals. No statical experiments can ascertain the quantity of our perspiration; as a continued absorption of the moisture of the atmosphere exists at the same time both by the cutaneous and pulmonary lymphatics. 3. Every gland is capable of being excited into greater exertions by an appropriated stimulus applied either by its mixture with the blood immediately to the secerning vessel, or applied externally to its excretory duct. Thus mercury internally promotes an increased salivation, and pyrethrum externally applied to the excretory ducts of the salival glands. Aloes stimulate the rectum internally mixed with the circulating blood; and sea-salt by injection externally. Now as the capillaries, which secrete the perspirable matter, lie near the surface of the body, the application of external heat acts immediately on their excretory ducts, and promotes perspiration; internally those drugs which possess a fragrant essential oil, or spiritus rector, produce this effect, as the aromatic vegetables, of which the number is very great. 4. It must be remembered, that a due quantity of some aqueous vehicle must be given to support this evacuation; otherwise a burning heat without much visible sweat must be the consequence. When the skin acquires a degree of heat much above 108, as appears by Dr. Alexander's experiments, no visible sweat is produced; which is owing to the great heat of the skin evaporating it as hastily, as it is secreted; and, where the sweat is secreted in abundance, its evaporation cannot carry off the exuberant heat, like the vapour of boiling water; because a great part of it is wiped off, or absorbed by the bed-clothes; or the air about the patient is not changed sufficiently often, as it becomes saturated with the perspirable matter. And hence it is probable, that the waste of perspirable matter is as great, or greater, when the skin is hot and dry, as when it stands in drops on the skin; as appears from the inextinguishable thirst. Hence Dr. Alexander found, that when the heat of the body was greater than 108, nothing produced sweats but repeated draughts of cold water; and of warm fluids, when the heat was much below that degree. And that cold water which procured sweats instantaneously when the heat was above 108, stopped them as certainly when it was below that heat; and that flannels, wrung out of warm water and wrapped round the legs and thighs, were then most certainly productive of sweats. 5. The diaphoretics are all said to succeed much better, if given early in the morning, about an hour before sun-rise, than at any other time; which is owing to the great excitability of every part of the system after the sensorial power has been accumulated during sleep. In those, who have hectic fever, or the febricula, or nocturnal fever of debility, the morning sweats are owing to the decline of the fever-fit, as explained in Sect. XXXII. 9. In some of these patients the sweat does not occur till they awake; because then the system is still more excitable than during sleep, because the assistance of the voluntary power in respiration facilitates the general circulation. See Class I. 2. 1. 3. 6. It must be observed, that the skin is very dry and hard to the touch, where the absorbents, which open on its surface, do not act; as in some dropsies, and other diseases attended with great thirst. This dryness, and shrivelled appearance, and roughness, are owing to the mouths of the absorbents being empty of their accustomed fluid, and is distinguishable from the dryness of the skin above mentioned in the hot fits of fever, by its not being attended with heat. As the heat of the skin in the usual temperature of the air always evinces an increased perspiration, whether visible or not, the heat being produced along with the increase of secretion; it follows, that a defect of perspiration can only exist, when the skin is cold. 7. Volatile alcali is a very powerful diaphoretic, and particularly if exhibited in wine-whey; 20 drops of spirit of hartshorn every half hour in half a pint of wine-whey, if the patient be kept in a moderately warm bed, will in a few hours elicit most profuse sweats. Neutral salts promote invisible perspiration, when the skin is not warmed much externally, as is evinced from the great thirst, which succeeds a meal of salt provisions, as of red herrings. When these are sufficiently diluted with water, and the skin kept warm, copious sweats without inflaming the habit, are the consequence. Half an ounce of vinegar saturated with volatile alcali, taken every hour or two hours, well answers this purpose; and is preferable perhaps in general to all others, where sweating is advantageous. Boerhaave mentions one cured of a fever by eating red-herrings or anchovies, which, with repeated draughts of warm water or tea, would I suppose produce copious perspiration. Antimonial preparations have also been of late much used with great advantage as diaphoretics. For the history and use of these preparations I shall refer the reader to the late writers on the Materia Medica, only observing that the stomach becomes so soon habituated to its stimulus, that the second dose may be considerably increased, if the first had no operation. Where it is advisable to procure copious sweats, the emetics, as ipecacuanha, joined with opiates, as in Dover's powder, produce this effect with greater certainty than the above. 8. We must not dismiss this subject without observing, that perspiration is designed to keep the skin flexile, as the tears are intended to clean and lubricate the eye; and that neither of these fluids can be considered as excretions in their natural state, but as secretions. See Class I. 1. 2. 3. And that therefore the principal use of diaphoretic medicines is to warm the skin, and thence in consequence to produce the natural degree of insensible perspiration in languid habits. 9. When the skin of the extremities is cold, which is always a sign of present debility, the digestion becomes frequently impaired by association, and cardialgia or heartburn is induced from the vinous or acetous fermentation of the aliment. In this disease diaphoretics, which have been called cordials, by their action on the stomach restore its exertion, and that of the cutaneous capillaries by their association with it, and the skin becomes warm, and the digestion more vigorous. 10. But a blister acts with more permanent and certain effect by stimulating a part of the skin, and thence affecting the whole of it, and of the stomach by association, and thence removes the most obstinate heartburns and vomitings. From this the principal use of blisters is understood, which is to invigorate the exertions of the arterial and lymphatic vessels of the skin, producing an increase of insensible perspiration, and of cutaneous absorption; and to increase the action of the stomach, and the consequent power of digestion; and thence by sympathy to excite all the other irritative motions: hence they relieve pains of the cold kind, which originate from defect of motion; not from their introducing a greater pain, as some have imagined, but by stimulating the torpid vessels into their usual action; and thence increasing the action and consequent warmth of the whole skin, and of all the parts which are associated with it. II. 1. _Sialagogues._ The preparations of mercury consist of a solution or corrosion of that metal by some acid; and, when the dose is known, it is probable that they are all equally efficacious. As their principal use is in the cure of the venereal disease, they will be mentioned in the catalogue amongst the sorbentia. Where salivation is intended, it is much forwarded by a warm room and warm clothes; and prevented by exposing the patient to his usual habits of cool air and dress, as the mercury is then more liable to go off by the bowels. 2. Any acrid drug, as pyrethrum, held in the mouth acts as a sialagogue externally by stimulating the excretory ducts of the salivary glands; and the siliqua hirsuta applied externally to the parotid gland, and even hard substances in the ear, are said to have the same effect. Mastich chewed in the mouth emulges the salivary glands. 3. The unwise custom of chewing and smoking tobacco for many hours in a day not only injures the salivary glands, producing dryness in the mouth when this drug is not used, but I suspect that it also produces schirrhus of the pancreas. The use of tobacco in this immoderate degree injures the power of digestion, by occasioning the patient to spit out that saliva, which he ought to swallow; and hence produces that flatulency, which the vulgar unfortunately take it to prevent. The mucus, which is brought from the fauces by hawking, should be spit out, as well as that coughed up from the lungs; but that which comes spontaneously into the mouth from the salivary glands, should be swallowed mixed with our food or alone for the purposes of digestion. See Class I. 2. 2. 7. III. 1. Expectorants are supposed to increase the secretion of mucus in the branches of the windpipe, or to increase the perspiration of the lungs secreted at the terminations of the bronchial artery. 2. If any thing promotes expectoration toward the end of peripneumonies, when the inflammation is reduced by bleeding and gentle cathartics, small repeated blisters about the chest, with tepid aqueous and mucilaginous or oily liquids, are more advantageous than the medicines generally enumerated under this head; the blisters by stimulating into action the vessels of the skin produce by association a greater activity of those of the mucous membrane, which lines the branches of the windpipe, and air-cells of the lungs; and thus after evacuation they promote the absorption of the mucus and consequent healing of the inflamed membrane, while the diluting liquids prevent this mucus from becoming too viscid for this purpose, or facilitate its expuition. Blisters, one at a time, on the sides or back, or on the sternum, are also useful towards the end of peripneumonies, by preventing the evening access of cold fit, and thence preventing the hot fit by their stimulus on the skin; in the same manner as five drops of laudanum by its stimulus on the stomach. For the increased actions of the vessels of the skin or stomach excite a greater quantity of the sensorial power of association, and thus prevent the torpor of the other parts of the system; which, when patients are debilitated, is so liable to return in the evening. 3. Warm bathing is of great service towards the end of peripneumony to promote expectoration, especially in those children who drink too little aqueous fluids, as it gently increases the action of the pulmonary capillaries by their content with the cutaneous ones, and supplies the system with aqueous fluid, and thus dilutes the secreted mucus. Some have recommended oil externally around the chest, as well as internally, to promote expectoration; and upon the nose, when its mucous membrane is inflamed, as in common catarrh. IV. 1. Diuretics. If the skin be kept warm, most of these medicines promote sweat instead of urine; and if their dose is enlarged, most of them become cathartic. Hence the neutral salts are used in general for all these purposes. Those indeed, which are composed of the vegetable acid, are most generally used as sudorifics; those with the nitrous acid as diuretics; and those with the vitriolic acid as cathartics: while those united with the marine acid enter our common nutriment, as a more general stimulus. All these increase the acrimony of the urine, hence it is retained a less time in the bladder; and in consequence less of it is reabsorbed into the system, and the apparent quantity is greater, as more is evacuated from the bladder; but it is not certain from thence, that a greater quantity is secreted by the kidnies. Hence nitre, and other neutral salts, are erroneously given in the gonorrhoea; as they augment the pain of making water by their stimulus on the excoriated or inflamed urethra. They are also erroneously given in catarrhs or coughs, where the discharge is too thin and saline, as they increase the frequency of coughing. 2. Balsam of Copaiva is thought to promote urine more than the other native balsams; and common resin is said to act as a powerful diuretic in horses. These are also much recommended in gleets, and in fluor albus, perhaps more than they deserve; they give a violet smell to the urine, and hence probably increase the secretion of it. Calcined egg-shells are said to promote urine, perhaps from the phosphoric acid they contain. 3. Cold air and cold water will increase the quantity of urine by decreasing the absorption from the bladder; and neutral and alcalious salts and cantharides by stimulating the neck of the bladder to discharge the urine as soon as secreted; and alcohol as gin and rum at the beginning of intoxication, if the body be kept cool, occasion much urine by inverting the urinary lymphatics, and thence pouring a fluid into the bladder, which never passed the kidnies. But it is probable, that those medicines, which give a scent to the urine as the balsams and resins, but particularly asparagus and garlic, are the only drugs, which truly increase the secretion of the kidnies. Alcohol however, used as above mentioned, and perhaps great doses of tincture of cantharides, may be considered as drastic diuretics, as they pour a fluid into the bladder by the retrograde action of the lymphatics, which are in great abundance spread about the neck of it. See Sect. XXIX. 3. V. Mild cathartics. The ancients believed that some purges evacuated the bile, and hence were termed Cholagogues; others the lymph, and were termed Hydragogues; and that in most each cathartic selected a peculiar humour, which it discharged. The moderns have too hastily rejected this system; the subject well deserves further observation. Calomel given in the dose from ten to twenty grains, so as to induce purging without the assistance of other drugs, appears to me to particularly increase the secretion of bile, and to evacuate it; aloe seems to increase the secretion of the intestinal mucus; and it is probable that the pancreas and spleen may be peculiarly stimulated into action by some other of this tribe of medicines; whilst others of them may simply stimulate the intestinal canal to evacuate its contents, as the bile of animals. It must be remarked, that all these cathartic medicines are supposed to be exhibited in their usual doses, otherwise they become drastic purges, and are treated of in the Class of Invertentia. VI. The mucus of the bladder is seen in the urine, when cantharides have been used, either internally or externally, in such doses as to induce the strangury. Spirit of turpentine is said to have the same effect. I have given above a dram of it twice a day floating on a glass of water in chronic lumbago without this effect, and the patient gradually recovered. VII. Aloe given internally seems to act chiefly on the rectum and, spincter ani, producing tenesmus and piles. Externally in clysters or suppositories, common salt seems to act on that bowel with greater certainty. But where the thread-worm or ascarides exist, 60 or 100 grains of aloes reduced to powder and boiled in a pint of gruel, and used as a clyster twice a week for three months, has frequently destroyed them. VIII. The external application of cantharides by stimulating the excretory ducts of the capillary glands produces a great secretion of subcutaneous mucus with pain and inflammation; which mucaginous fluid, not being able to permeate the cuticle, raises it up; a similar secretion and elevation of the cuticle is produced by actual fire; and by caustic materials, as by the application of the juice of the root of white briony, or bruised mustard-seed. Experiments are wanting to introduce some acrid application into practice instead of cantharides, which might not induce the strangury. Mustard-seed alone is too acrid, and if it be suffered to lie on the skin many minutes is liable to produce a slough and consequent ulcer, and should therefore be mixed with flour when applied to cold extremities. Volatile alkali properly diluted might stimulate the skin without inducing strangury. IX. The mild errhines are such as moderately stimulate the membrane of the nostrils, so as to increase the secretion of nasal mucus; as is seen in those, who are habituated to take snuff. The stronger errhines are mentioned in Art. V. 2. 3. X. The secretion of tears is increased either by applying acrid substances to the eye; or acrid vapours, which stimulate the excretory duct of the lacrymal gland; or by applying them to the nostrils, and stimulating the excretory duct of the lacrymal sack, as treated of in the Section on Instinct. Or the secretion of tears is increased by the association of the motions of the excretory duct of the lacrymal sack with ideas of tender pleasure, or of hopeless distress, as explained in Sect. XVI. 8. 2. and 3. XI. The secretion of sensorial power in the brain is probably increased by opium or wine, because when taken in certain quantity an immediate increase of strength and activity succeeds for a time, with consequent debility if the quantity taken be so great as to intoxicate in the least degree. The necessity of perpetual respiration shews, that the oxygen of the atmosphere supplies the source of the spirit of animation; which is constantly expended, and is probably too fine to be long contained in the nerves after its production in the brain. Whence it is probable, that the respiration of oxygen gas mixed with common air may increase the secretion of sensorial power; as indeed would appear from its exhilarating effect on most patients. III. CATALOGUE OF THE SECERNENTIA. I. Diaphoretics. 1. Amomum zinziber, ginger. Caryophyllus aromaticus, cloves. Piper indicum, pepper. Capsicum. Cardamomum. Pimento, myrtus pimenta. Canella alba. Serpentaria virginiana, aristolochia serpentaria, guaiacum. Sassafras, laurus sassafras. Opium. Wine. 2. Essential oils of cinnamon, laurus cinnamomum. Nutmeg, myristica moschata. Cloves, caryophyllus aromaticus. Mint, mentha. Camphor, laurus camphora. Ether. 3. Volatile salts, as of ammoniac and of hartshorn. Sal cornu cervi. 4. Neutral salts, as those with vegetable acid; or with marine acid, as common salt. Halex. Red-herring, anchovy. 5. Preparations of antimony, as emetic tartar, antimonium tartarizatum, wine of antimony. James's powder. 6. External applications. Blisters. Warm bath. Warm air. Exercise. Friction. 7. Cold water with subsequent warmth. II. Sialagogues. Preparations of mercury, hydrargyrus. Pyrethrum, anthemis pyrethrum, tobacco, cloves, pepper, cowhage, stizolobium siliqua hirsuta. Mastich, pistacia lentiscus. III. Expectorants: 1. Squill, scilla maritima, garlic, leek, onion, allium, asafoetida, ferula asafoetida, gum ammoniac, benzoin, tar, pix liquida, balsam of Tolu. 2. Root of seneka, polygala seneka, of elicampane, inula helenium. 3. Marsh-mallow, althæa, coltsfoot, tussilago farfara, gum arabic, mimosa nilotica, gum tragacanth, astragalus tragacantha. Decoction of barley, hordeum distichon. Expressed oils. Spermaceti, soap. Extract of liquorice, glycyrrhiza glabra. Sugar. Honey. 4. Externally blisters. Oil. Warm bath. IV. Mild diuretics. 1. Nitre, kali acetatum, other neutral salts. 2. Fixed alkali, soap, calcined egg-shells. 3. Turpentine. Balsam of Copaiva. Resin. Olibanum. 4. Asparagus, garlic, wild daucus. Parsley, apium. Fennel fæniculum, pareira brava, Cissampelos? 5. Externally cold air, cold water. 6. Alcohol. Tincture of cantharides. Opium. V. Mild cathartics. 1. Sweet subacid fruits. Prunes, prunus domestica. Cassia sistula. Tamarinds, crystals of tartar, unrefined sugar. Manna. Honey. 2. Whey of milk, bile of animals. 3. Neutral salts, as Glauber's salt, vitriolated tartar, sea-water, magnesia alba, soap. 4. Gum guaiacum. Balsam of Peru. Oleum ricini, castor-oil, oil of almonds, oil of olives, sulphur. 5. Senna, cassia senna, jalap, aloe, rhubarb, rheum palmatum. 6. Calomel. Emetic tartar, antimonium tartarizatum. VI. Secretion of mucus of the bladder is increased by cantharides, by spirit of turpentine? VII. Secretion of mucus of the rectum is increased by aloe internally, by various clysters and suppositories externally. VIII. Secretion of subcutaneous mucus is increased by blisters of cantharides, by application of a thin slice of the fresh root of white briony, by sinapisms, by root of horse-radish, cochlearia armoracia. Volatile alcali. IX. Mild errhines. Marjoram. Origanum. Marum, tobacco. X. Secretion of tears is increased by vapour of sliced onion, of volatile alcali. By pity, or ideas of hopeless distress. XI. Secretion of sensorial power in the brain is probably increased by opium, by wine, and perhaps by oxygen gas added to the common air in respiration. * * * * * ART. IV. SORBENTIA. I. Those things which increase the irritative motions, which constitute absorption, are termed sorbentia; and are as various as the absorbent vessels, which they stimulate into action. 1. Cutaneous absorption is increased by austere acids, as of vitriol; hence they are believed to check colliquative sweats, and to check the eruption of small-pox, and contribute to the cure of the itch, and tinea; hence they thicken the saliva in the mouth, as lemon-juice, crab-juice, sloes. 2. Absorption from the mucous membrane is increased by opium, and Peruvian bark, internally; and by blue vitriol externally. Hence the expectoration in coughs, and the mucous discharge from the urethra, are thickened and lessened. 3. Absorption from the cellular membrane is promoted by bitter vegetables, and by emetics, and cathartics. Hence matter is thickened and lessened in ulcers by opium and Peruvian bark; and serum is absorbed in anasarca by the operation of emetics and cathartics. 4. Venous absorption is increased by acrid vegetables; as water-cress, cellery, horse-radish, mustard. Hence their use in sea-scurvy, the vibices of which are owing to a defect of venous absorption; and by external stimulants, as vinegar, and by electricity, and perhaps by oxygen. 5. Intestinal absorption is increased by astringent vegetables, as rhubarb, galls; and by earthy salts, as alum; and by argillaceous and calcareous earth. 6. Hepatic absorption is increased by metallic salts, hence calomel and sal martis are so efficacious in jaundice, worms, chlorosis, dropsy. 7. Venereal virus in ulcers is absorbed by the stimulus of mercury; hence they heal by the use of this medicine. 8. Venesection, hunger, thirst, and violent evacuations, increase all absorptions; hence sweating produces costiveness. 9. Externally bitter astringent vegetables, earthy and metallic salts, and bandages, promote the absorption of the parts on which they are applied. 10. All these in their usual doses do not increase the natural heat; but they induce costiveness, and deep coloured urine with earthy sediment. In greater doses they invert the motions of the stomach and lacteals; and hence vomit or purge, as carduus benedictus, rhubarb. They promote perspiration, if the skin be kept warm; as camomile tea, and testaceous powders, have been used as sudorifics. The preparations of antimony vomit, purge, or sweat, either according to the quantity exhibited, or as a part of what is given is evacuated. Thus a quarter of a grain of emetic tartar (if well prepared) will promote a diaphoresis, if the skin be kept warm; half a grain will procure a stool or two first, and sweating afterwards; and a grain will generally vomit, and then purge, and lastly sweat the patient. In less quantity it is probable, that this medicine acts like other metallic salts, as steel, zinc, or copper in small doses; that is, that it strengthens the system by its stimulus. As camomile or rhubarb in different doses vomit, or purge, or act as stimulants so as to strengthen the system. II. OBSERVATIONS ON THE SORBENTIA. I. 1. As there is great difference in the apparent structure of the various glands, and of the fluids which they select from the blood, these glands must possess different kinds of irritability, and are therefore stimulated into stronger or unnatural actions by different articles of the materia medica, as shewn in the secernentia. Now as the absorbent vessels are likewise glands, and drink up or select different fluids, as chyle, water, mucus, with a part of every different secretion, as a part of the bile, a part of the saliva, a part of the urine, &c. it appears, that these absorbent vessels must likewise possess different kinds of irritability, and in consequence must require different articles of the materia medica to excite them into unusual action. This part of the subject has been so little attended to, that the candid reader will find in this article a great deal to excuse. It was observed, that some of the secernentia did in a less degree increase absorption, from the combination of different properties in the same vegetable body; for the same reason some of the class of sorbentia produce secretion in a less degree, as those bitters which have also an aroma in their composition; these are known from their increasing the heat of the system above its usual degree. It must also be noted, that the actions of every part of the absorbent system are so associated with each other, that the drugs which stimulate one branch increase the action of the whole; and the torpor or quiescence of one branch weakens the exertions of the whole; or when one branch is excited into stronger action, some other branch has its actions weakened or inverted. Yet though peculiar branches of the absorbent system are stimulated into action by peculiar substances, there are other substances which seem to stimulate the whole system, and that without immediately increasing any of the secretions; as those bitters which possess no aromatic scent, at the head of which stands the famed Peruvian bark, or cinchona. 2. Cutaneous absorption. I have heard of some experiments, in which the body was kept cold, and was thought to absorb more moisture from the atmosphere than at any other time. This however cannot be determined by statical experiments; as the capillary vessels, which secrete the perspirable matter, must at the same time have been benumbed by the cold; and from their inaction there could not have been the usual waste of the weight of the body; and as all other muscular exertions are best performed, when the body possesses its usual degree of warmth, it is conclusive, that the absorbent system should likewise do its office best, when it is not benumbed by external cold. The austere acids, as of vitriol, lemon-juice, juice of crabs and sloes, strengthen digestion, and prevent that propensity to sweat so usual to weak convalescents, and diminish the colliquative sweats in hectic fevers; all which are owing to their increasing the action of the external and internal cutaneous absorption. Hence vitriolic acid is given in the small-pox to prevent the too hasty or too copious eruption, which it effects, by increasing the cutaneous absorption. Vinegar, from the quantity of alcohol which it contains, exerts a contrary effect to that here described, and belongs to the incitantia; as an ounce of it promotes sweat, and a flushing of the skin; at the same time externally it acts as a venous absorbent, as the lips become pale by moistening them with it. And it is said, when taken internally in great and continued quantity, to induce paleness of the skin, and softness of the bones. The sweet vegetable acids, as of several ripe fruits, are among the torpentia; as they are less stimulating than the general food of this climate, and are hence used in inflammatory diseases. Where the quantity of fluids in the system is much lessened, as in hectic fever, which has been of some continuance, or in spurious peripneumony, a grain of opium given at night will sometimes prevent the appearance of sweats; which is owing to the stimulus of opium increasing the actions of the cutaneous absorbents, more than those of the secerning vessels of the skin. Whence the secretion of perspirable matter is not decreased, but its appearance on the skin is prevented by its more facile absorption. 3. There is one kind of itch, which seldom appears between the fingers, is the least infectious, and most difficult to eradicate, and which has its cure much facilitated by the internal use of acid of vitriol. This disease consists of small ulcers in the skin, which are healed by whatever increases the cutaneous absorption. The external application of sulphur, mercury, and acrid vegetables, acts on the same principle; for the animalcula, which are seen in these pustules, are the effect, not the cause, of them; as all other stagnating animal fluids, as the semen itself, abounds with similar microscopic animals. 4. Young children have sometimes an eruption upon the head called Tinea, which discharges an acrimonius ichor inflaming the parts, on which it falls. This eruption I have seen submit to the internal use of vitriolic acid, when only wheat-flour was applied externally. This kind of eruption is likewise frequently cured by testaceous powders; two materials so widely different in their chemical properties, but agreeing in their power of promoting cutaneous absorption. II. Absorption from the mucous membrane is increased by applying to its surface the austere acids, as of vitriol, lemon-juice, crab-juice, sloes. When these are taken into the mouth, they immediately thicken, and at the same time lessen the quantity of the saliva; which last circumstance cannot be owing to their coagulating the saliva, but to their increasing the absorption of the thinner parts of it. So alum applied to the tip of the tongue does not stop in its action there, but independent of its diffusion it induces cohesion and corrugation over the whole mouth. (Cullen's Mat. Med. Art. Astringentia.) Which is owing to the association of the motions of the parts or branches of the absorbent system with each other. Absorption from the mucous membrane is increased by opium taken internally in small doses more than by any other medicine, as is seen in its thickening the expectoration in coughs, and the discharge from the nostrils in catarrh, and perhaps the discharge from the urethra in gonorrhoea. The bark seems next in power for all these purposes. Externally slight solutions of blue vitriol, as two or three grains to an ounce of water, applied to ulcers of the mouth, or to chancres on the glans penis, more powerfully induces them to heal than any other material. Where the lungs or urethra are inflamed to a considerable degree, and the absorption is so great, that the mucus is already too thick, and adheres to the membrane from its viscidity, opiates and bitter vegetable and austere acids are improper; and mucilaginous diluents should be used in their stead with venesection and torpentia. III. 1. Absorption from the cellular membrane, and from all the other cavities of the body, is too slowly performed in some constitutions; hence the bloated pale complexion; and when this occurs in its greatest degree, it becomes an universal dropsy. These habits are liable to intermittent fevers, hysteric paroxysms, cold extremities, indigestion, and all the symptoms of debility. The absorbent system is more subject to torpor or quiescence than the secerning system, both from the coldness of the fluids which are applied to it, as the moisture of the atmosphere, and from the coldness of the fluids which we drink; and also from its being stimulated only by intervals, as when we take our food; whereas the secerning system is perpetually excited into action by the warm circulating blood; as explained in Sect. XXXII. 2. The Peruvian bark, camomile flowers, and other bitter drugs, by stimulating this cellular branch of the absorbent system prevents it from becoming quiescent; hence the cold paroxysms of those agues, which arise from the torpor of the cellular lymphatics, are prevented, and the hot fits in consequence. The patient thence preserves his natural heat, regains his healthy colour, and his accustomed strength. Where the cold paroxysm of an ague originates in the absorbents of the liver, spleen, or other internal viscus, the addition of steel to vegetable bitters, and especially after the use of one dose of calomel, much advances the cure. And where it originates in any part of the secerning system, as is probably the case in some kinds of agues, the addition of opium in the dose of a grain and half, given about an hour before the access of the paroxysm, or mixed with chalybeate and bitter medicines, ensures the cure. Or the same may be effected by wine given instead of opium before the paroxysm, so as nearly to intoxicate. These three kinds of agues are thus distinguished; the first is not attended with any tumid or indurated viscus, which the people call an ague cake, and which is evident to the touch. The second is accompanied with a tumid viscus; and the last has generally, I believe, the quartan type, and is attended with some degree of arterial debility. 3. This class of absorbent medicines are said to decrease irritability. After any part of our system has been torpid or quiescent, by whatever cause that was produced, it becomes afterwards capable of being excited into greater motion by small stimuli; hence the hot fit of fever succeeds the cold one. As these medicines prevent torpor or quiescence of parts of the system, as cold hands or feet, which perpetually happen to weak constitutions, the subsequent increase of irritability of these parts is likewise prevented. 4. These absorbent medicines, including both the bitters, and metallic salts, and opiates, are of great use in the dropsy by their promoting universal absorption; but here evacuations are likewise to be produced, as will be treated of in the Invertentia. 5. The matter in ulcers is thickened, and thence rendered less corrosive, the saline part of it being reabsorbed by the use of bitter medicines; hence the bark is used with advantage in the cure of ulcers. 6. Bitter medicines strengthen digestion by promoting the absorption of chyle; hence the introduction of hop into the potation used at our meals, which as a medicine may be taken advantageously, but, like other unnecessary stimuli, must be injurious as an article of our daily diet. The hop may perhaps in some degree contribute to the production of gravel in the kidnies, as our intemperate wine-drinkers are more subject to the gout, and ale-drinkers to the gravel; in the formation of both which diseases, there can be no doubt, but that the alcohol is the principal, if not the only agent. 7. Vomits greatly increase the absorption from the cellular membrane, as squill, and foxglove. The squill should be given in the dose of a grain of the dried root every hour, till it operates upwards and downwards. Four ounces of the fresh leaves of the foxglove should be boiled from two pounds of water to one, and half an ounce of the decoction taken every two hours for four or more doses. This medicine by stimulating into inverted action the absorbents of the stomach, increases the direct action of the cellular lymphatics. Another more convenient way of ascertaining the dose of foxglove is by making a saturated tincture of it in proof spirit; which has the twofold advantage of being invariable in its original strength, and of keeping a long time as a shop-medicine without losing any of its virtue. Put two ounces of the leaves of purple foxglove, digitalis purpurea, nicely dried, and coarsely powdered, into a mixture of four ounces of rectified spirit of wine and four ounces of water; let the mixture stand by the fire-side twenty-four hours frequently shaking the bottle, and thus making a saturated tincture of digitalis; which must be poured from the sediment or passed through filtering paper. As the size of a drop is greater or less according to the size of the rim of the phial from which it is dropped, a part of this saturated tincture is then directed to be put into a two-ounce phial, for the purpose of ascertaining the size of the drop. Thirty drops of this tincture is directed to be put into an ounce of mint-water for a draught to be taken twice or thrice a day, till it reduces the anasarca of the limbs, or removes the difficulty of breathing in hydrothorax, or till it induces sickness. And if these do not occur in two or three days, the dose must be gradually increased to forty or sixty drops, or further. From the great stimulus of this medicine the stomach is rendered torpid with consequent sickness, which continues many hours and even days, owing to the great exhaustion of its sensorial power of irritation; and the action of the heart and arteries becomes feeble from the deficient excitement of the sensorial power of association; and lastly, the absorbents of the cellular membrane act more violently in consequence of the accumulation of the sensorial power of association in the torpid heart and arteries, as explained in Suppl. I. 12. A circumstance curiously similar to this occurs to some people on smoking tobacco for a short time, who have not been accustomed to it. A degree of sickness is presently induced, and the pulsations of the heart and arteries become feeble for a short time, as in the approach to fainting, owing to the direct sympathy between these and the stomach, that is from defect of the excitement of the power of association. Then there succeeds a tingling, and heat, and sometimes sweat, owing to the increased action of the capillaries, or perspirative and mucous glands; which is occasioned by the accumulation of the sensorial power of association by the weaker action of the heart and arteries, which now increases the action of the capillaries. 8. Another method of increasing absorption from the cellular membrane is by warm air, or by warm steam. If the swelled legs of a dropsical patient are inclosed in a box, the air of which is made warm by a lamp or two, copious sweats are soon produced by the increased action of the capillary glands, which are seen to stand on the skin, as it cannot readily exhale in so small a quantity of air, which is only changed so fast as may be necessary to permit the lamps to burn. At the same time the lymphatics of the cellular membrane are stimulated by the heat into greater action, as appears by the speedy reduction of the tumid legs. It would be well worth trying an experiment upon a person labouring under a general anasarca by putting him into a room filled with air heated to 120 or 130 degrees, which would probably excite a great general diaphoresis, and a general cellular absorption both from the lungs and every other part. And that air of so great heat may be borne for many minutes without great inconvenience was shewn by the experiments made in heated rooms by Dr. Fordyce and others. Philos. Trans. Another experiment of using warmth in anasarca, or in other diseases, might be by immersing the patient in warm air, or in warm steam, received into an oil-skin bag, or bathing-tub of tin, so managed, that the current of warm air or steam should pass round and cover the whole of the body except the head, which might not be exposed to it; and thus the absorbents of the lungs might be induced to act more powerfully by sympathy with the skin, and not by the stimulus of heat. See Uses of Warm Bath, Art. II. 2. 2. 1. IV. 1. Venous absorption. Cellary, water-cresses, cabbages, and many other vegetables of the Class Tetradynamia, do not increase the heat of the body (except those whose acrimony approaches to corrosion), and hence they seem alone, or principally, to act on the venous system; the extremities of which we have shewn are absorbents of the red blood, after it has passed the capillaries and glands. 2. In the sea-scurvy and petechial fever the veins do not perfectly perform this office of absorption; and hence the vibices are occasioned by blood stagnating at their extremities, or extravasated into the cellular membrane. And this class of vegetables, stimulating the veins to perform their natural absorption, without increasing the energy of the arterial action, prevents future petechiæ, and may assist the absorption of the blood already stagnated, as soon as its chemical change renders it proper for that operation. 3. The fluids, which are extravasated, and received into the cells of the cellular membrane, seem to continue there for many days, so as to undergo some chemical change, and are then taken up again by the mouths of the cellular absorbents. But the new vessels produced in inflamed parts, as they communicate with the veins, are probably absorbed again by the veins along with the blood which they contain in their cavities. Hence the blood, which is extravasated in bruises or vibices, is gradually many days in disappearing; but after due evacuations the inflamed vessels on the white of the eye, if any stimulant lotion is applied, totally disappear in a few hours. Amongst absorbents affecting the veins we should therefore add the external application of stimulant materials; as of vinegar, which makes the lips pale on touching them. Friction, and electricity. 4. Hæmorrhages are of two kinds, either arterial, which are attended with inflammation; or venous, from a deficiency in the absorbent power of this set of vessels. In the former case the torpentia are efficacious; in the latter steel, opium, alum, and all the tribe of sorbentia, are used with success. 5. Sydenham recommends vegetables of the class Tetradynamia in rheumatic pains left after the cure of intermittents. These pains are perhaps similar to those of the sea-scurvy, and seem to arise from want of absorption in the affected part, and hence are relieved by the same medicines. V. 1. Intestinal absorption. Some astringent vegetables, as rhubarb, may be given in such doses as to prove cathartic; and, after a part of it is evacuated from the body, the remaining part augments the absorption of the intestines; and acts, as if a similar dose had been exhibited after the operation of any other purgative. Hence 4 grains of rhubarb strengthen the bowels, 30 grains first empty them. 2. The earthy salts, as alum, increase the intestinal absorption, and hence induce constipation in their usual dose; alum is said sometimes to cure intermittents, perhaps when their seat is in the intestines, when other remedies have failed. It is useful in the diabætes by exciting the absorbents of the bladder into their natural action; and combined with resin is esteemed in the fluor albus, and in gleets. Lime-stone or chalk, and probably gypsum, possess effects in some degree similar, and increase the absorption of the intestines; and thus in certain doses restrain some diarrhoeas, but in greater doses alum I suppose will act as a cathartic. Five or ten grains produce constipation, 20 or 30 grains are either emetic or cathartic. 3. Earth of alum, tobacco-pipe clay, marl, Armenian bole, lime, crab's eyes or claws, and calcined hartshorn, or bone ashes, restrain fluxes; either mechanically by supplying something like mucilage, or oil, or rollers to abate the friction of the aliment over inflamed membranes; or by increasing their absorption. The two last consist of calcareous earth united to phosphoric acid, and the Armenian bole and marl may contain iron. By the consent between the intestines and the skin 20 grains of Armenian bole given at going into bed to hectic patients will frequently check their tendency to sweat as well as to purge, and the more certainly if joined with one grain of opium. VI. 1. Absorption from the liver, stomach, and other viscera. When inflammations of the liver are subdued to a certain degree by venesection, with calomel and other gentle purges, so that the arterial energy becomes weakened, four or eight grains of iron-filings, or of salt of steel, with the Peruvian bark, have wonderful effect in curing the cough, and restoring the liver to its usual size and sanity; which it seems to effect by increasing the absorption of this viscus. The same I suppose happens in respect to the tumours of other viscera, as of the spleen, or pancreas, some of which are frequently enlarged in agues. 2. Hæmorrhages from the nose, rectum, kidnies, uterus, and other parts, are frequently attendant on diseased livers; the blood being impeded in the vena portarum from the decreased power of absorption, and in consequence of the increased size of this viscus. These hæmorrhages after venesection, and a mercurial cathartic, are most certainly restrained by steel alone, or joined with an opiate; which increase the absorption, and diminish the size of the liver. Chalybeates may also restrain these hæmorrhages by their promoting venous absorption, though they exert their principal effect upon the liver. Hence also opiates, and bitters, and vitriolic acid, are advantageously used along with them. It must be added that some hæmorrhages recur by periods like the paroxysms of intermittent fevers, and are thence cured by the same treatment. 3. The jaundice is frequently caused by the insipidity of the bile, which does not stimulate the gall-bladder and bile-ducts into their due action; hence it stagnates in the gall-bladder, and produces a kind of crystallization, which is too large to pass into the intestines, blocks up the bile-duct, and occasions a long and painful disease. A paralysis of the bile duct produces a similar jaundice, but without pain. 4. Worms in sheep called flukes are owing to the dilute state of the bile; hence they originate in the intestines, and thence migrate into the biliary ducts, and corroding the liver produce ulcers, cough, and hectic fever, called the rot. In human bodies it is probable the inert state of the bile is one cause of the production of worms; which insipid state of the bile is owing to deficient absorption of the thinner parts of it; hence the pale and bloated complexion, and swelled upper lip, of wormy children, is owing to the concomitant deficiency of absorption from the cellular membrane. Salt of steel, or the rust of it, or filings of it, with bitters, increase the acrimony of the bile by promoting the absorption of its aqueous part; and hence destroy worms, as well as by their immediate action on the intestines, or on the worms themselves. The cure is facilitated by premising a purge with calomel. See Class I. 2. 3. 9. 5. The chlorosis is another disease owing to the deficient action of the absorbents of the liver, and perhaps in some degree also to that of the secretory vessels, or glands, which compose that viscus. Of this the want of the catameniæ, which is generally supposed to be a cause, is only a symptom or consequence. In this complaint the bile is deficient perhaps in quantity, but certainly in acrimony, the thinner parts not being absorbed from it. Now as the bile is probably of great consequence in the process of making the blood; it is on this account that the blood is so destitute of red globules; which is evinced by the great paleness of these patients. As this serous blood must exert less stimulus on the heart, and arteries, the pulse in consequence becomes quick as well as weak, as explained in Sect. XII. 1. 4. The quickness of the pulse is frequently so great and permanent, that when attended by an accidental cough, the disease may be mistaken for hectic fever; but is cured by chalybeates, and bitters exhibited twice a day; with half a grain of opium, and a grain of aloe every night; and the expected catamenia appears in consequence of a restoration of the due quantity of red blood. This and the two former articles approach to the disease termed paralysis of the liver. Sect. XXX. 1. 4. 6. It seems paradoxical, that the same treatment with chalybeates, bitters, and opiates, which produces menstruation in chlorotic patients, should repress the too great or permanent menstruation, which occurs in weak constitutions at the time of life when it should cease. This complaint is an hæmorrhage owing to the debility of the absorbent power of the veins, and belongs to the paragraph on venous absorption above described, and is thence curable by chalybeates, alum, bitters, and particularly by the exhibition of a grain of opium every night with five grains of rhubarb. 7. Metallic salts supply us with very powerful remedies for promoting absorption in dropsical cases; which frequently are caused by enlargement of the liver. First, as they may be given in such quantities as to prove strongly cathartic, of which more will be said in the article on invertentia; and then, when their purgative quality ceases, like the effect of rhubarb, their absorbent quality continues to act. The salts of mercury, silver, copper, iron, zinc, antimony, have all been used in the dropsy; either singly for the former purpose, or united with bitters for the latter, and occasionally with moderate but repeated opiates. 8. From a quarter of a grain to half a grain of blue vitriol given every four or six hours, is said to be very efficacious in obstinate intermittents; which also frequently arise from an enlarged viscus, as the liver or spleen, and are thence owing to the deficient absorption of the lymphatics of that viscus. A quarter of a grain of white arsenic, as I was informed by a surgeon of the army, cures a quartan ague with great certainty, if it be given an hour before the expected fit. This dose he said was for a robust man, perhaps one eighth of a grain might be given and repeated with greater safety and equal efficacy. Dr. Fowler has given many successful cases in his treatise on this subject. He prepares it by boiling sixty-four grains of white arsenic in a Florence flask along with as much pure vegetable fixed alcali in a pint of distilled water, till it is dissolved, and then adding to it as much distilled water as will make the whole exactly sixteen ounces. Hence there are four grains of arsenic in every ounce of the solution. This should be put into a phial of such a size of the edge of its aperture, that sixty drops may weigh one dram, which will contain half a grain of arsenic. To children from two years old to four he gives from two to five drops three or four times a day. From five years old to seven, he directs seven or eight drops. From eight years old to twelve, he directs from seven to ten drops. From thirteen years old to eighteen he directs from ten to twelve drops. From eighteen upwards, twelve drops. In so powerful a medicine it is always prudent to begin with smaller doses, and gradually to increase them. A saturated solution of arsenic in water is preferable I think to the above operose preparation of it; as no error can happen in weighing the ingredients, and it more certainly therefore possesses an uniform strength. Put much more white arsenic reduced to powder into a given quantity of distilled water, than can be dissolved in it. Boil it for half an hour in a Florence flask, or in a tin sauce-pan; let it stand to subside, and filter it through paper. My friend Mr. Greene, a surgeon at Brewood in Staffordshire, assured me, that he had cured in one season agues without number with this saturated solution; that he found ten drops from a two-ounce phial given thrice a day was a full dose for a grown person, but that he generally began with five. 9. The manner, in which arsenic acts in curing intermittent fevers, cannot be by its general stimulus, because no intoxication or heat follows the use of it; nor by its peculiar stimulus on any part of the secreting system, since it is not in small doses succeeded by any increased evacuation, or heat, and must therefore exert its power, like other articles of the sorbentia, on the absorbent system. In what manner it destroys life so suddenly is difficult to understand, as it does not intoxicate like many vegetable poisons, nor produce fevers like contagious matter. When applied externally it seems chemically to destroy the part like other caustics. Does it chemically destroy the stomach, and life in consequence? or does it destroy the action of the stomach by its great stimulus, and life in consequence of the sympathy between the stomach and the heart? This last appears to be the most probable mode of its operation. The success of arsenic in the cure of intermittent fevers I suspect to depend on its stimulating the stomach into stronger action, and thus, by the association of this viscus with the heart and arteries, preventing the torpor of any part of the sanguiferous system. I was led to this conclusion from the following considerations. First. The effects of arsenic given a long time internally in small doses, or when used in larger quantities externally, seem to be similar to those of other great stimuli, as of wine or alcohol. These are a bloated countenance, swelled legs, hepatic tumours, and dropsy, and sometimes eruptions on the skin. The former of these I have seen, where arsenic has been used externally for curing the itch; and the latter appears on evidence in the famous trial of Miss Blandy at Chelmsford, about forty years ago. Secondly. I saw an ague cured by arsenic in a child, who had in vain previously taken a very large quantity of bark with great regularity. And another case of a young officer, who had lived intemperately, and laboured under an intermittent fever, and had taken the bark repeatedly in considerable quantities, with a grain of opium at night, and though the paroxysms had been thrice thus for a time prevented, they recurred in about a week. On taking five drops of a saturated solution of arsenic thrice a day the paroxysms ceased, and returned no more, and at the same time his appetite became much improved. Thirdly. A gentleman about 65 years of age had for about ten years been subject to an intermittent pulse, and to frequent palpitations of his heart. Lately the palpitations seemed to observe irregular periods, but the intermission of every third or fourth pulsation was almost perpetual. On giving him four drops of a saturated solution of arsenic from a two-ounce phial about every four hours for one day, not only the palpitation did not return, but the intermission ceased entirely, and did not return so long as he took the medicine, which was three or four days. Now as when the stomach has its action much weakened by an over-dose of digitalis, the pulse is liable to intermit, this evinces a direct sympathy between these parts of the system, and as I have repeatedly observed, that when the pulse begins to intermit in elderly people, that an eructation from the stomach, voluntarily produced, will prevent the threatened stop of the heart; I am induced to think, that the torpid state of the stomach, at the instant of the production of air occasioned by its weak action, caused the intermission of the pulse. And that arsenic in this case, as well as in the cases of agues above mentioned, produced its effects by stimulating the stomach into more powerful action; and that the equality of the motions of the heart was thus restored by increasing the excitement of the sensorial power of association. See Sect. XXV. 17. Class IV. 2. 1. 18. 10. Where arsenic has been given as a poison, it may be discovered in the contents of the stomach by the smell like garlic, when a few grains of it are thrown on a red-hot iron. 2. If a few grains are placed between two plates of copper, and subjected to a red heat, the copper becomes whitened. 3. Dissolve arsenic in water along with vegetable alcali, add to this a solution of blue vitriol in water, and the mixture becomes of a fine green, which gradually precipitates, as discovered by Bergman. 4. Where the quantity is sufficient, some wheat may be steeped in a solution of it, which given to sparrows or chickens will destroy them. VII. Absorption of the matter from venereal ulcers. No ulcer can heal, unless the absorption from it is as great as the deposition in it. The preparations or oxydes of mercury in the cure of the venereal disease seem to act by their increasing the absorption of the matter in the ulcers it occasions; and that whether they are taken into the stomach, or applied on the skin, or on the surface of the ulcers. And this in the same manner as sugar of lead, or other metallic oxydes, promote so rapidly the healing of other ulcers by their external application; and probably when taken internally, as rust of iron given to children affected with scrophulous ulcers contributes to heal them, and solutions of lead were once famous in phthisis. The matter deposited in large abscesses does not occasion hectic fever, till it has become oxygenated by being exposed to the open air, or to the air through a moist membrane; the same seems to happen to other kinds of matter, which produce fever, or which occasion spreading ulcers, and are thence termed contagious. See Class II. 1. 3. II. 1. 5. II. 1. 6. 6. This may perhaps occur from these matters not being generally absorbed, till they become oxygenated; and that it is the stimulus of the acid thus formed by their union with oxygen, which occasions their absorption into the circulation, and the fever, which they then produce. For though collections of matter, and milk, and mucus, are sometimes suddenly absorbed during the action of emetics or in sea-sickness, they are probably eliminated from the body without entering the circulation; that is, they are taken up by the increased action of one lymphatic branch, and evacuated by the inverted action of some other lymphatic branch, and thus carried off by stool or urine. But as the matter in large abscesses is in general not absorbed, till it becomes by some means exposed to air, there is reason to conclude, that the stimulus of this new combination of the matter with oxygen occasions its absorption; and that hence the absorption of matter in ulcers of all kinds, is still more powerfully effected by the external application or internal use of metallic oxydes; which are also acids consisting of the metal united with oxygen; and lastly, because venereal ulcers, and those of itch, and tinea, will not heal without some stimulant application; that is, the secretion of matter in them continues to be greater, than the absorption of it; and the ulcers at the same time continue to enlarge, by the contagion affecting the edges of them; that is, by the stimulus of the oxygenated matter stimulating the capillary vessels in its vicinity into actions similar to those of the ulcer, which produces it. This effect of the oxydes of mercury occurs, whether salivation attends its use or not. Salivation is much forwarded by external warmth, when mercury is given to promote this secretion; but as the cure of venereal complaints depends on its absorbent quality, the act of salivation is not necessary or useful. A quarter of a grain of good corrosive sublimate twice a day will seldom fail of curing the most confirmed pox; and will as seldom salivate, if the patient be kept cool. A quarter of a grain thrice a day I believe to be infallible, if it be good sublimate. Mercury alone when swallowed does not act beyond the intestines, its active preparations are the salts formed by its union with the various acids, as mentioned in the catalogue. Its union with the vegetable acid, when triturated with manna, is said to compose Keyser's Pill. Triturated with gum arabic it is much recommended by Plenk; and triturated with sugar and a little essential oil, as directed in a former Edinburgh Dispensatory, it probably forms some of the syrups sold as nostrums. United with sulphur it seldom enters the circulation, as when cinnabar, or Æthiop's mineral, are taken inwardly. But united with fat and rubbed on the skin, it is readily absorbed. I know not whether it can be united to charcoal, nor whether it has been given internally when united with animal fat. VIII. 1. Absorptions in general are increased by inanition; hence the use of evacuations in the cure of ulcers. Dr. Jurin absorbed in one night, after a day's abstinence and exercise, eighteen ounces from the atmosphere in his chamber; and every one must have observed, how soon his sheets became dry, after having been moistened by sweat, if he throws off part of the bed-clothes to cool himself; which is owing to the increased cutaneous absorption after the evacuation by previous sweat. 2. Now as opium is an universal stimulant, as explained in the article on Incitantia, it must stimulate into increased action both the secretory system, and the absorbent one; but after repeated evacuation by venesection, and cathartics, the absorbent system is already inclined to act more powerfully; as the blood-vessels being less distended, there is less resistance to the progress of the absorbed fluids into them. Hence after evacuations opium promotes absorption, if given in small doses, much more than it promotes secretion; and is thus eminently of service at the end of inflammations, as in pleurisy, or peripneumony, in the dose of four or five drops of the tincture, given before the access of the evening paroxysm; which I have seen succeed even when the risus sardonicus has existed. Some convulsions may originate in the want of the absorption of some acrid secretion, which occasions pain; hence these diseases are so much more certainly relieved by opium after venesection or other evacuations. IX. 1. Absorption is increased by the calces or solutions of mercury, lead, zinc, copper, iron, externally applied; and by arsenic, and by sulphur, and by the application of bitter vegetables in fine powder. Thus an ointment consisting of mercury and hog's fat rubbed on the skin cures venereal ulcers; and many kinds of herpetic eruptions are removed by an ointment consisting of 60 grains of white precipitate of mercury and an ounce of hog's fat. 2. The tumours about the necks of young people are often produced by the absorption of a saline or acrid material, which has been deposited from eruptions behind the ears, owing to deficient absorption in the surface of the ulcer, but which on running down on the skin below becomes absorbed, and swells the lymphatic glands of the neck; as the variolous matter, when inserted into the arm, swells the gland of the axilla. Sometimes the perspirative matter produced behind the ears becomes putrid from the want of daily washing them, and may also cause by its absorption the tumours of the lymphatics of the neck. In the former case the application of a cerate of lapis calaminaris, or of cerussa applied in dry powder, or of rags dipped in a solution of sugar of lead, increases the absorption in the ulcers, and prevents the effusion of the saline part of the secreted material. The latter is to be prevented by cleanliness. After the eruptions or ulcers are healed a solution of corrosive sublimate of one grain to an ounce of water applied for some weeks behind the ear, and amongst the roots of the hair on one side of the head, where the mouths of the lymphatics of the neck open themselves, frequently removes these tumours. 3. Linen rags moistened with a solution of half an ounce of sugar of lead to a pint of water applied on the erysipelas on anasarcous legs, which have a tendency to mortification, is more efficacious than other applications. White vitriol six grains dissolved in one ounce of rose-water removes inflammations of the eyes after evacuation more certainly than solutions of lead. Blue vitriol two or three grains dissolved in an ounce of water cures ulcers in the mouth, and other mucous membranes, and a solution of arsenic externally applied cures the itch, but requires great caution in the use of it. See Class II. 1. 5. 6. 4. Bitter vegetables, as the Peruvian bark, quilted between two shirts, or strewed in their beds, will cure the ague in children sometimes. Iron in solution, and some bitter extract, as in the form of ink, will cure one kind of herpes called the ringworm. And I have seen seven parts of bark in fine powder mixed with one part of ceruss, or white lead, in fine powder, applied dry to scrophulous ulcers, and renewed daily, with great advantage. 5. To these should be added electric sparks and shocks, which promote the absorption of the vessels in inflamed eyes of scrophulous children; and disperse, or bring to suppuration, scrophulous tumours about the neck. For this last purpose smart shocks should be passed through the tumours only, by inclosing them between two brass knobs communicating with the external and internal coating of a charged phial. See Art. II. 2. 2. 2. X. 1. Bandages increase absorption, if they are made to fit nicely on the part; for which purpose it is necessary to spread some moderately adhesive plaster on the bandage, and to cut it into tails, or into shreds two inches wide; the ends are to be wrapped over each other; and it must be applied when the part is least tumid, as in the morning before the patient rises, if on the lower extremities. The emplastrum de minio made to cover the whole of a swelled leg in this manner, whether the swelling is hard, which is usually termed scorbutic; or more easily compressible, as in anasarca, reduces the limb in two or three days to its natural size; for this purpose I have sometimes used carpenter's glue, mixed with one twentieth part of honey to prevent its becoming too hard, instead of a resinous plaster; but the minium plaster of the shops is in general to be preferred. Nothing so much facilitates the cure of ulcers in the legs, as covering the whole limb from the toes to the knee with such a plaster-bandage; which increases the power of absorption in the surface of the sore. 2. The lymph is carried along the absorbent vessels, which are replete with valves, by the intermitted pressure of the arteries in their neighbourhood. Now if the external skin of the limb be lax, it rises, and gives way to the pressure of the arteries at every pulsation; and thence the lymphatic vessels are subject to the pressure of but half the arterial force. But when the external skin is tightened by the surrounding bandage, and thence is not elevated by the arterial diastole, the whole of this power is exerted in compressing the lymphatic vessels, and carrying on the lymph already absorbed; and thence the absorbent power is so amazingly increased by bandage nicely applied. Pains are sometimes left in the fleshy parts of the thighs or arms, after the inflammation is gone, in the acute rheumatism, or after the patient is too weak for further evacuation; in this case after internal absorbent medicines, as the bark, and opiates, have been used in vain, I have successfully applied a plaster-bandage, as above described, so as to compress the pained part. XI. 1. We shall conclude by observing, that the sorbentia strengthen the whole habit by preventing the escape of the fluid part of the secretions out of the body, before it has given up as much nourishment, as it is capable; as the liquid part of the secretion of urine, sweat, saliva, and of all other secretions, which are poured into receptacles. Hence they have been said to brace the body, and been called tonics, which are mechanical terms not applicable to the living bodies of animals; as explained in Sect. XXXII. 3. 2. 2. A continued use of bitter medicines for years together, as of Portland's powder, or of the bark, is supposed to induce apoplexy, or other fatal diseases. Two cases of this kind have fallen under my observation; the patients were both rather intemperate in respect to the use of fermented liquors, and one of them had been previously subject to the gout. As I believe the gout generally originates from a torpor of the liver, which instead of being succeeded by an inflammation of it, is succeeded by an inflammation of some of the joints; or by a pimpled face, which is another mode, by which the disease of the liver is terminated. I conceive, that the daily use of bitter medicine had in these patients prevented the removal of a gouty inflammation from the liver to the membranes of the joints of the extremities, or to the skin of the face, by preventing the necessary torpor of these parts previous to the inflammation of them; in the same manner as cold fits of fever are prevented by the same medicines; and, as I believe, the returns of the gout have sometimes for two or three years been prevented by them. One of these patients died of the apoplexy in a few hours; and the other of an inflammation of the liver, which I believe was called the gout, and in consequence was not treated by venesection, and other evacuations. From hence it appears, that the daily use of hop in our malt liquor must add to the noxious quality of the spirit in it, when taken to excess, and contribute to the production of apoplexy, or inflammation of the liver. III. CATALOGUE OF THE SORBENTIA. I. Sorbentia affecting the skin. 1. Acid of vitriol, of sea-salt, lemons, sloes, prunus spinosa, crabs, pyrus, quince, pyrus cydonia, opium. 2. Externally calx of zinc, of lead, of mercury. II. Sorbentia affecting the mucous membranes. 1. Juice of sloes, crabs, Peruvian bark, cinchona, opium. 2. Externally blue vitriol. III. Sorbentia affecting the cellular membrane. 1. Peruvian bark, wormwoods, artemisia maritima, artemisia absynthium, worm-seed, artemisia santonicum, chamomile, anthemis nobilis, tansey tanacetum, bogbean, menyanthes trifoliata, centaury, gentiana centaurium, gentian, gentiana lutea, artichoke-leaves, cynara scolymus, hop, humulus lupulus. 2. Orange-peel, cinnamon, nutmeg, mace. 3. Vomits, squill, digitalis, tobacco. 4. Bath of warm air, of steam. IV. Sorbentia affecting the veins. 1. Water-cress, sisymbrium nasturtium aquaticum, mustard, sinapis, scurvy-grass cochlearia hortensis, horse-radish cochlearia armoracia, cuckoo-flower, cardamine, dog's-grass, dandelion, leontodon taraxacon, cellery apium, cabbage brassica. 2. Chalybeates, bitters, and opium, after sufficient evacuation. 3. Externally vinegar, friction, electricity. V. Sorbentia affecting the intestines. 1. Rhubarb, rheum palmatum, oak-galls, gallæ quercinæ, tormentil, tormentilla erecta, cinquefoil potentilla, red-roses, uva ursi, simarouba. 2. Logwood, hæmatoxylum campechianum, succus acaciæ, dragon's blood, terra japonica, mimosa catechu. 3. Alum, earth of alum, Armenian bole, chalk, creta, crab's claws, chelæ cancrorum, white clay, cimolia, calcined hartshorn, cornu cervi calcinatum, bone-ashes. VI. Sorbentia affecting the liver, stomach, and other viscera. Rust of iron, filings of iron, salt of steel, sal martis, blue vitriol, white vitriol, calomel, emetic tartar, sugar of lead, white arsenic. VII. Sorbentia affecting venereal ulcers. Mercury dissolved or corroded by the following acids: 1. Dissolved in vitriolic acid, called turpeth mineral, or hydrargyrus vitriolatus. 2. Dissolved in nitrous acid, called hydrargyrus nitratus ruber. 3. Dissolved in muriatic acid, mercurius corrosivus sublimatus, or hydrargyrus muriatus. 4. Corroded by muriatic acid. Calomel. 5. Precipitated from muriatic acid, mercurius precipitatus albus, calx hydrargyri alba. 6. Corroded by carbonic acid? The black powder on crude mercury. 7. Calcined, or united with oxygen. 8. United with animal fat, mercurial ointment. 9. United with sulphur. Cinnabar. 10. Partially united with sulphur. Æthiops mineral. 11. Divided by calcareous earth. Hydrargyrus cum cretâ. 12. Divided by vegetable mucilage, by sugar, by balsams. VIII. Sorbentia affecting the whole system. Evacuations by venesection and catharsis, and then by the exhibition of opium. IX. Sorbentia externally applied. 1. Solutions of mercury, lead, zinc, copper, iron, arsenic; or metallic calces applied in dry powder, as cerussa, lapis calaminaris. 2. Bitter vegetables in decoctions and in dry powders, applied externally, as Peruvian bark, oak bark, leaves of wormwood, of tansey, camomile flowers or leaves. 3. Electric sparks, or shocks. X. Bandage spread with emplastrum e minio, or with carpenter's glue mixed with one twentieth part of honey. XI. Portland's powder its continued use pernicious, and of hops in beer. * * * * * ART. V. INVERTENTIA. I. Those things, which invert the natural order of the successive irritative motions, are termed invertentia. 1. Emetics invert the motions of the stomach, duodenum, and oesophagus. 2. Violent cathartics invert the motions of the lacteals, and intestinal lymphatics. 3. Violent errhines invert the nasal lymphatics, and those of the frontal and maxillary sinuses. And medicines producing nausea, invert the motions of the lymphatics about the sauces. 4. Medicines producing much pale urine, as a certain quantity of alcohol, invert the motions of the urinary absorbents; if the dose of alcohol is greater, it inverts the stomach, producing the drunken sickness. 5. Medicines producing cold sweats, palpitation of the heart, globus hystericus; as violent evacuations, some poisons, fear, anxiety, act by inverting the natural order of the vascular motions. II. OBSERVATIONS ON THE INVERTENTIA. I. 1. The action of vomiting seems originally to have been occasioned by disagreeable sensation from the distention or acrimony of the aliment; in the same manner as when any disgustful material is taken into the mouth, as a bitter drug, and is rejected by the retrograde motions of the tongue and lips; as explained in Class IV. 1. 1. 2. and mentioned in Sect. XXXV. 1. 3. Or the disagreeable sensation may thus excite the power of volition, which may also contribute to the retrograde actions of the stomach and oesophagus, as when cows bring up the contents of their first stomach to re-masticate it. To either of these is to be attributed the action of mild emetics, which soon cease to operate, and leave the stomach stronger, or more irritable, after their operation; owing to the accumulation of the sensorial power of irritation during its torpid or inverted action. Such appears to be the operation of ipecacuanha, or of antimonium tartarizatum, in small doses. 2. But there is reason to believe, that the stronger emetics, as digitalis, first stimulate the absorbent vessels of the stomach into greater action; and that the inverted motions of these absorbents next occur, pouring the lymph, lately taken up, or obtained from other lymphatic branches, into the stomach: the quantity of which in some diseases, as in the cholera morbus, is inconceivable. This inverted motion, first of the absorbents of the stomach, and afterwards of the stomach itself, seems to originate from the exhaustion or debility, which succeeds the unnatural degree of action, into which they had been previously stimulated. An unusual defect of stimulus, as of food without spice or wine in the stomachs of those, who have been much accustomed to spice or wine, will induce sickness or vomiting; in this case the defective energy of the stomach is owing to defect of accustomed stimulus; while the action of vomiting from digitalis is owing to a deficiency of sensorial power, which is previously exhausted by the excess of its stimulus. See Sect. XXXV. 1. 3. and Class IV. 1. 1. 2. For first, no increase of heat arises from this action of vomiting; which always occurs, when the secerning system is stimulated into action. Secondly, the motions of the absorbent vessels are as liable to inversion as the stomach itself; which last, with the oesophagus, may be considered as the absorbent mouth and belly of that great gland, the intestinal canal. Thirdly, the class of sorbentia, as bitters and metallic salts, given in large doses, become invertentia, and vomit, or purge. And lastly, the sickness and vomiting induced by large potations of wine, or opium, does not occur till next day in some people, in none till some time after their ingurgitation. And tincture of digitalis in the dose of 30 or 60 drops, though applied in solution, is a considerable time before it produces its effect; though vomiting is instantaneously induced by a nauseous idea, or a nauseous taste in the mouth. At the same time there seem to be some materials, which can immediately stimulate the stomach into such powerful action, as to be immediately succeeded by paralysis of it, and consequent continued fever, or immediate death; and this without exciting sensation, that is, without our perceiving it. Of these are the contagious matter of some fevers swallowed with the saliva, and probably a few grains of arsenic taken in solution. See Suppl. I. 8. 8. Art. IV. 2. 6. 9. 3. Some branches of the lymphatic system become inverted by their sympathy with other branches, which are only stimulated into too violent absorption. Thus when the stomach and duodenum are much stimulated by alcohol, by nitre, or by worms, in some persons the urinary lymphatics have their motion inverted, and pour that material into the bladder, which is absorbed from the intestines. Hence the drunken diabetes is produced; and hence chyle is seen in the urine in worm cases. When on the contrary some branches of the absorbent systems have their motions inverted in consequence of the previous exhaustion of their sensorial power by any violent stimulus, other branches of it have their absorbent power greatly increased. Hence continued vomiting, or violent cathartics, produce great absorption from the cellular membrane in cases of dropsy; and the fluids thus absorbed are poured into the stomach and intestines by the inverted motions of the lacteals and lymphatics. See Sect. XXIX. 4. and 5. 4. The quantity of the dose of an emetic is not of so great consequence as of other medicines, as the greatest part of it is rejected with the first effort. All emetics are said to act with greater certainty when given in a morning, if an opiate had been given the night before. For the sensorial power of irritation of the stomach had thus been in some measure previously exhausted by the stimulus of the opium, which thus facilitates the action of the emetic; and which, when the dose of opium has been large, is frequently followed on the next day by spontaneous sickness and vomitings, as after violent intoxication. Ipecacuanha is the most certain in its effect from five grains to thirty; white vitriol is the most expeditious in its effect, from twenty grains to thirty dissolved in warm water; but emetic tartar, antimonium tartarizatum, from one grain to four to sane people, and from thence to twenty to insane patients, will answer most of the useful purposes of emetics; but nothing equals the digitalis purpurea for the purpose of absorbing water from the cellular membrane in the anasarca pulmonum, or hydrops pectoris. See Art. IV. 2. 3. 7. II. Violent cathartics. 1. Where violent cathartics are required, as in dropsies, the squill in dried powder made into small pills of a grain, or a grain and a half, one to be given every hour till they operate briskly, is very efficacious; or half a grain of emetic tartar dissolved in an ounce of peppermint-water, and given every hour, till it operates. Scammony, and other strong purges, are liable to produce hypercatharsis, if they are not nicely prepared, and accurately weighed, and are thence dangerous in common practice. Gamboge is uncertain in its effects, it has otherwise the good property of being tasteless; and on that account some preparation of it might be useful for children, by which its dose could be ascertained, and its effects rendered more uniform. 2. In inflammations of the bowels with constipation calomel, given in the dose from ten to twenty grains after due venesection, is most efficacious; and if made into very small pills is not liable to be rejected by vomiting, which generally attends those cases. When this fails, a grain of aloes every hour will find its way, if the bowel is not destroyed; and sometimes, I believe, if it be, when the mortification is not extensive. If the vomiting continues after the pain ceases, and especially if the bowels become tumid with air, which sounds on being struck with the finger, these patients seldom recover. Opiates given along with the cathartics I believe to be frequently injurious in inflammation of the bowels, though they may thus be given with advantage in the saturnine colic; the pain and constipation in which disease are owing to torpor or inactivity, and not to too great action. III. Violent errhines and sialagogues. 1. Turpeth mineral in the quantity of one grain mixed with ten grains of sugar answers every purpose to be expected from errhines. Their operation is by inverting the motions of the lymphatics of the membrane, which lines the nostrils, and the caverns of the forehead and cheeks; and may thence possibly be of service in the hydrocephalus internus. Some other violent errhines, as the powder of white hellebore, or Cayan pepper, diluted with some less acrid powder, are said to cure some cold or nervous head-achs; which may be effected by inflaming the nostrils, and thus introducing the sensorial power of sensation, as well as increasing that of irritation; and thus to produce violent action of the membranes of the nostrils, and of the frontal and maxillary sinuses, which may by association excite into action the torpid membranes, which occasion the head-ach. 2. A copious salivation without any increase of heat often attends hysteric diseases, and fevers with debility, owing to an inversion of the lymphatics of the mouth, see Class I. 1. 2. 6. The same occurs in the nausea, which precedes vomiting; and is also excitable by disagreeable tastes, as by squills, or by nauseous smells, or by nauseous ideas. These are very similar to the occasional discharge of a thin fluid from the nostrils of some people, which recurs at certain periods, and differs from defective absorption. IV. Violent diuretics. 1. If nitre be given from a dram to half an ounce in a morning at repeated draughts, the patient becomes sickish, and much pale water is thrown into the bladder by the inverted action of the urinary lymphatics. Hence the absorption in ulcers is increased and the cure forwarded, as observed by Dr. Rowley. 2. Cantharides taken inwardly so stimulate the neck of the bladder as to increase the discharge of mucus, which appears in the urine; but I once saw a large dose taken by mistake, not less than half an ounce or an ounce of the tincture, by which I suppose the urinary lymphatics were thrown into violent inverted motions, for the patient drank repeated draughts of subtepid water to the quantity of a gallon or two in a few hours; and during the greatest part of that time he was not I believe two entire minutes together without making water. A little blood was seen in his water the next day, and a soreness continued a day longer without any other inconvenience. 3. The decoction of foxglove should also be mentioned here, as great effusions of urine frequently follow its exhibition. See Art. IV. 2. 3. 7. And an infusion or tincture of tobacco as recommended by Dr. Fowler of York. 4. Alcohol, and opium, if taken so as to induce slight intoxication, and the body be kept cool, and much diluting liquids taken along with them, have similar effect in producing for a time a greater flow of urine, as most intemperate drinkers must occasionally have observed. This circumstance seems to have introduced the use of gin, and other vinous spirits as a diuretic, unfortunately in the gravel, amongst ignorant people; which disease is generally produced by fermented or spirituous liquors, and always increased by them. 5. Fear and anxiety are well known to produce a great frequency of making water. A person, who believed he had made a bad purchase concerning an estate, told me, that he made five or six pints of water during a sleepless night, which succeeded his bargain; and it is usual, where young men are waiting in an anti-room to be examined for college preferment, to see the chamber-pot often wanted. V. Cold sweats about the head, neck, and arms, frequently attend those, whose lungs are oppressed, as in some dropsies and asthma. A cold sweat is also frequently the harbinger of death. These are from the inverted motions of the cutaneous lymphatic branches of those parts. III. CATALOGUE OF INVERTENTIA. I. Emetics, ipecacuanha, emetic tartar, antimonium tartarisatum, squill, scilla maritima, carduus benedictus, cnicus acarna, chamoemile, anthemis nobilis, white vitriol, vitriolum zinci, foxglove, digitalis purpurea, clysters of tobacco. II. Violent cathartics, emetic tartar, squill, buckthorn, rhamnus catharticus, scammonium, convolvulus scammonia, gamboge, elaterium, colocynth, cucumis colocynthis, veratrum. III. Violent errhines and sialagogues, Turpeth mineral, hydrargyrus vitriolatus, asarum europæum, euphorbium, capsicum, veratrum, nauseous smells, nauseous ideas. IV. Violent diuretics, nitre, squill, seneka, cantharides, alcohol, foxglove, tobacco, anxiety. V. Cold sudorifics, poisons, fear, approaching death. * * * * * ART. VI. REVERTENTIA. I. Those things, which restore the natural order of the inverted irritative motions, are termed Revertentia. 1. As musk, castor, asafoetida, valerian, essential oils. 2. Externally the vapour of burnt feathers, of volatile salts, or oils, blisters, sinapisms. These reclaim the inverted motions without increasing the heat of the body above its natural state, if given in their proper doses, as in the globus hystericus, and palpitation of the heart. The incitantia revert these morbid motions more certainly, as opium and alcohol; and restore the natural heat more; but if they induce any degree of intoxication, they are succeeded by debility, when their stimulus ceases. II. OBSERVATIONS ON THE REVERTENTIA. I. The hysteric disease is attended with inverted motions feebly exerted of the oesophagus, intestinal canal and lymphatics of the bladder. Hence the borborigmi, or rumbling of the bowels, owing to their fluid contents descending as the air beneath ascends. The globus hystericus consists in the retrograde motion of the oesophagus, and the great flow of urine from that of the lymphatics spread on the neck of the bladder; and a copious salivation sometimes happens to these patients from the inversion of the lymphatics of the mouth; and palpitation of the heart owing to weak or incipient inversion of its motions; and syncope, when this occurs in its greatest degree. These hysteric affections are not necessarily attended with pain; though it sometimes happens, that pains, which originate from quiescence, afflict these patients, as the hemicrania, which has erroneously been termed the clavus hystericus; but which is owing solely to the inaction of the membranes of that part, like the pains attending the cold fits of intermittents, and which frequently returns like them at very regular periods of time. Many of the above symptoms are relieved by musk, castor, the foetid gums, valerian, oleum animale, oil of amber, which act in the usual dose without heating the body. The pains, which sometimes attend these constitutions, are relieved by the secernentia, as essential oils in common tooth-ach, and balsam of Peru in the flatulent colic. But the incitantia, as opium, or vinous spirit, reclaim these morbid inverted motions with more certainty, than the foetids; and remove the pains, which attend these constitutions, with more certainty than the secernentia; but if given in large doses, a debility and return of the hysteric symptoms occurs, when the effect of the opium or alcohol ceases. Opiates and foetids joined seem best to answer the purpose of alleviating the present symptoms; and the sorbentia, by stimulating the lymphatics and lacteals into continued action, prevent a relapse of their inversion, as Peruvian bark, and rust of iron. See Class I. 3. 1. 10. II. Vomiting consists in the inverted order of the motions of the stomach, and oesophagus; and is also attended with the inverted motions of a part of the duodenum, when bile is ejected; and of the lymphatics of the stomach and fauces, when nausea attends, and when much lymph is evacuated. Permanent vomiting is for a time relieved by the incitantia, as opium or alcohol; but is liable to return, when their action ceases. A blister on the back, or on the stomach, is more efficacious for restraining vomiting by their stimulating into action the external skin, and by sympathy affecting the membranes of the stomach. In some fevers attended with incessant vomiting Sydenham advised the patient to put his head under the bed-clothes, till a sweat appeared on the skin, as explained in Class IV. 1. 1. 2. In chronical vomiting I have observed crude mercury of good effect in the dose of half an ounce twice a day. The vomitings, or vain efforts to vomit, which sometimes attend hysteric or epileptic patients, are frequently instantly relieved for a time by applying flour of mustard-seed and water to the small of the leg; and removing it, as soon as the pain becomes considerable. If sinapisms lie on too long, especially in paralytic cases, they are liable to produce troublesome ulcers. A plaster or cataplasm, with opium and camphor on the region of the stomach, will sometimes revert its retrograde motions. III. Violent catharsis, as in diarrhoea or dysentery, is attended with inverted motions of the lymphatics of the intestines, and is generally owing to some stimulating material. This is counteracted by plenty of mucilaginous liquids, as solutions of gum arabic, or small chicken broth, to wash away or dilute the stimulating material, which causes the disease. And then by the use of the intestinal sorbentia, Art. IV. 2. 5. as rhubarb, decoction of logwood, calcined hartshorn, Armenian bole; and lastly, by the incitantia, as opium. IV. The diabætes consists in the inverted motions of the urinary lymphatics, which is generally I suppose owing to the too great action of some other branch of the absorbent system. The urinary branch should be stimulated by cantharides, turpentine, resin (which when taken in larger doses may possibly excite it into inverted action), by the sorbentia and opium. The intestinal lymphatics should be rendered less active by torpentia, as calcareous earth, earth of alum; and those of the skin by oil externally applied over the whole body; and by the warm-bath, which should be of 96 or 98 degrees of heat, and the patient should sit in it every day for half an hour. V. Inverted motions of the intestinal canal with all the lymphatics, which open into it, constitute the ileus, or iliac passion; in which disease it sometimes happens, that clysters are returned by the mouth. After venesection from ten grains to twenty of calomel made into very small pills; if this is rejected, a grain of aloe every hour; a blister; crude mercury; warm-bath; if a clyster of iced water? Many other inverted motions of different parts of the system are described in Class I. 3. and which are to be treated in a manner similar to those above described. It must be noted, that the medicines mentioned under number one in the catalogue of revertentia are the true articles belonging to this class of medicines. Those enumerated in the other four divisions are chiefly such things as tend to remove the stimulating causes, which have induced the inversion of the motions of the part, as acrimonious contents, or inflammation, of the bowels in diarrhoea, diabetes, or in ileus. But it is probable after these remote causes are destroyed, that the fetid gums, musk, castor, and balsams, might be given with advantage in all these cases. III. CATALOGUE OF REVERTENTIA. I. Inverted motions, which attend the hysteric disease, are reclaimed, 1. By musk, castor. 2. By asafoetida, galbanum, sagapænum, ammoniacum, valerian. 3. Essential oils of cinnamon, nutmeg, cloves, infusion of penny-royal, mentha, pulegium, peppermint, mentha piperita, ether, camphor. 4. Spirit of hartshorn, oleum animale, spunge burnt to charcoal, black-snuffs of candles, which consist principally of animal charcoal, wood-soot, oil of amber. 5. The incitantia, as opium, alcohol, vinegar. 6. Externally the smoke of burnt feathers, oil of amber, volatile salt applied to the nostrils, blisters, sinapisms. II. Inverted motions of the stomach are reclaimed by opium, alcohol, blisters, crude mercury, sinapisms, camphor and opium externally, clysters with asafoetida. III. Inverted motions of the intestinal lymphatics are reclaimed by mucilaginous diluents, and by intestinal sorbentia, as rhubarb, logwood, calcined hartshorn, Armenian bole; and lastly by incitantia, as opium. IV. Inverted motions of the urinary lymphatics are reclaimed by cantharides, turpentine, rosin, the sorbentia, and opium, with calcareous earth, and earth of alum, by oil externally, warm-bath. V. Inverted motions of the intestinal canal are reclaimed by calomel, aloe, crude mercury, blisters, warm-bath, clysters with asafoetida, clysters of iced water? or of spring water further cooled by salt dissolved in water contained in an exterior vessel? Where there exists an introsusception of the bowel in children, could the patient be held up for a time by the feet with his head downwards, or be laid with his body on an inclined plane with his head downwards, and crude mercury be injected as a clyster to the quantity of two or three pounds? * * * * * ART. VII. TORPENTIA. I. Those things, which diminish the exertion of the irritative motions, are termed torpentia. 1. As mucus, mucilage, water, bland oils, and whatever possesses less stimulus than our usual food. Diminution of heat, light, sound, oxygen, and of all other stimuli; venesection, nausea, and anxiety. 2. Those things which chemically destroy acrimony, as calcareous earth, soap, tin, alcalies, in cardialgia; or which prevent chemical acrimony, as acid of vitriol in cardialgia, which prevents the fermentation of the aliment in the stomach, and its consequent acidity. Secondly, which destroy worms, as calomel, iron filings or rust of iron, in the round worms; or amalgama of quicksilver and tin, or tin in very large doses, in the tape-worms. Will ether in clysters destroy ascarides? Thirdly, by chemically destroying extraneous bodies, as caustic alcali, lime, mild alcali in the stone. Fourthly, those things which lubricate the vessels, along which extraneous bodies slide, as oil in the stone in the urethra, and to expedite the expectoration of hardened mucus; or which lessen the friction of the contents in the intestinal canal in dysentery or aphtha, as calcined hartshorn, clay, Armenian bole, chalk, bone-ashes. Fifthly, such things as soften or extend the cuticle over tumors, or phlegmons, as warm water, poultices, fomentations, or by confining the perspirable matter on the part by cabbage-leaves, oil, fat, bee's-wax, plasters, oiled silk, externally applied. These decrease the natural heat and remove pains occasioned by excess of irritative motions. II. OBSERVATIONS ON THE TORPENTIA. I. As the torpentia consist of such materials as are less stimulating than our usual diet, it is evident, that where this class of medicines is used, some regard must be had to the usual manner of living of the patient both in respect to quantity and quality. Hence wounds in those, who have been accustomed to the use of much wine, are very liable to mortify, unless the usual potation of wine be allowed the patient. And in these habits I have seen a delirium in a fever cured almost immediately by wine; which was occasioned by the too mild regimen directed by the attendants. On the contrary in great inflammation, the subduction of food, and of spirituous drink, contributes much to the cure of the disease. As by these means both the stimulus from distention of the vessels, as well as that from the acrimony of the fluids, is decreased; but in both these respects the previous habits of diet of the patients must be attended to. Thus if tea be made stronger, than the patient has usually drank it, it belongs to the article sorbentia; if weaker, it belongs to the torpentia. II. Water in a quantity greater than usual diminishes the action of the system not only by diluting our fluids, and thence lessening their stimulus, but by lubricating the solids; for not only the parts of our solids have their sliding over each other facilitated by the interposition of aqueous particles; but the particles of mucaginous or saccharine solutions slide easier over each other by being mixed with a greater portion of water, and thence stimulate the vessels less. At the same time it must be observed, that the particles of water themselves, and of animal gluten dissolved in water, as the glue used by carpenters, slide easier over each other by an additional quantity of the fluid matter of heat. These two fluids of heat and of water may be esteemed the universal solvents or lubricants in respect to animal bodies, and thus facilitate the circulation, and the secretion of the various glands. At the same time it is possible, that these two fluids may occasionally assume an aerial form, as in the cavity of the chest, and by compressing the lungs may cause one kind of asthma, which is relieved by breathing colder air. An increased quantity of heat by adding stimulus to every part of the system belongs to the article Incitantia. III. 1. The application of cold to the skin, which is only another expression for the diminution of the degree of heat we are accustomed to, benumbs the cutaneous absorbents into inaction; and by sympathy the urinary and intestinal absorbents become also quiescent. The secerning vessels continuing their action somewhat longer, from the warmth of the blood. Hence the usual secretions are poured into the bladder and intestines, and no absorption is retaken from them. Hence sprinkling the skin with cold water increases the quantity of urine, which is pale; and of stool, which is fluid; these have erroneously been ascribed to increased secretion, or to obstructed perspiration. The thin discharge from the nostrils of some people in cold weather is owing to the torpid state of the absorbent vessels of the membrana sneideriana, which as above are benumbed sooner than those, which perform the secretion of the mucus. The quick anhelation, and palpitation of the heart, of those, who are immersed in cold water, depends on the quiescence of the external absorbent vessels and capillaries. Hence the cutaneous circulation is diminished, and by association an almost universal torpor of the system is induced; thence the heart becomes incapable to push forwards its blood through all the inactive capillaries and glands; and as the terminating vessels of the pulmonary artery suffer a similar inaction by association, the blood is with difficulty pushed through the lungs. Some have imagined, that a spasmodic constriction of the smaller vessels took place, and have thus accounted for their resistance to the force of the heart. But there seems no necessity to introduce this imaginary spasm; since those, who are conversant in injecting bodies, find it necessary first to put them into warm water to take away the stiffness of the cold dead vessels; which become inflexible like the other muscles of dead animals, and prevent the injected fluid from passing. All the same symptoms occur in the cold fits of intermittents; in these the coldness and paleness of the skin with thirst evince the diminution of cutaneous absorption; and the dryness of ulcers, and small secretion of urine, evince the torpor of the secerning system; and the anhelation, and coldness of the breath, shew the terminations of the pulmonary artery to be likewise affected with torpor. After these vessels of the whole surface of the body both absorbent and secretory have been for a time torpid by the application of cold water; and all the internal secerning and absorbent ones have been made torpid from their association with the external; as soon as their usual stimulus of warmth is renewed, they are thrown into more than their usual energy of action; as the hands become hot and painful on approaching the fire after having been immersed some time in snow. Hence the face becomes of a red colour in a cold day on turning from the wind, and the insensible perspiration increased by repeatedly going into frosty air, but not continuing in it too long at a time. 2. When by the too great warmth of a room or of clothes, the secretion of perspirable matter is much increased, the strength of the patient is much exhausted by this unnecessary exertion of the capillary system, and thence of the whole secerning and arterial system by association. The diminution of external heat immediately induces a torpor or quiescence of these unnecessary exertions, and the patient instantly feels himself strengthened, and exhilarated; the animal power, which was thus wasted in vain, being now applied to more useful purposes. Thus when the limbs on one side are disabled by a stroke of the palsy, those of the other side are perpetually in motion. And hence all people bear riding and other exercises best in cold weather. Patients in fevers, where the skin is hot, are immediately strengthened by cold air; which is therefore of great use in fevers attended with debility and heat; but may perhaps be of temporary disservice, if too hastily applied in some situations of fevers attended with internal topical inflammation, as in peripneumony or pleurisy, where the arterial strength is too great already, and the increased action of the external capillaries being destroyed by the cold, the action of the internal inflamed part may be suddenly increased, unless venesection and other evacuations are applied at the same time. Yet in most cases the application of cold is nevertheless salutary, as by decreasing the heat of the particles of blood in the cutaneous vessels, the stimulus of them, and the distention of the vessels becomes considerably lessened. In external inflammations, as the small-pox, and perhaps the gout and rheumatism, the application of cold air must be of great service by decreasing the action of the inflamed skin, though the contrary is too frequently the practice in those diseases. It must be observed, that for all these purposes the application of it should be continued a long time, otherwise an increased exertion follows the temporary torpor, before the disease is destroyed. 3. After immersion in cold water or in cold air the whole system becomes more exciteable by the natural degree of stimulus, as appears from the subsequent glow on the skin of people otherwise pale; and even by a degree of stimulus less than natural, as appears by their becoming warm in a short time during their continuance in a bath, of about 80 degrees of heat, as in Buxton bath. See Sect XII. 2. 1. XXXII. 3. 3. This increased exertion happens to the absorbent vessels more particularly, as they are first and most affected by these temporary diminutions of heat; and hence like the medicines, which promote absorption, the cold-bath contributes to strengthen the constitution, that is to increase its irritability; for the diseases attended with weakness, as nervous fevers and hysteric diseases, are shewn in Section XXXII. 2. 1. to proceed from a want of irritability, not from an excess of it. Hence the digestion is greater in frosty weather, and the quantity of perspiration. For these purposes the application of cold must not be continued too long. For in riding a journey in cold weather, when the feet are long kept too cold, the digestion is impaired, and cardialgia produced. 4. If the diminution of external heat be too great, produced too hastily, or continued too long, the torpor of the system either becomes so great, that the animal ceases to live; or so great an energy of motion or orgasm of the vessels succeeds, as to produce fever or inflammation. This most frequently happens after the body has been temporarily heated by exercise, warm rooms, anger, or intemperance. Hence colds are produced in the external air by resting after exercise, or by drinking cold water. See Class I. 2. 2. 1. Frequent cold immersions harden or invigorate the constitution, which they effect by habituating the body to bear a diminution of heat on its surface without being thrown into such extensive torpor or quiescence by the consent of the vessels of the skin with the pulmonary and glandular system; as those experience, who frequently use the cold-bath. At first they have great anhelation and palpitation of heart at their ingress into cold water; but by the habit of a few weeks they are able to bear this diminution of heat with little or no inconvenience; for the power of volition has some influence over the muscles subservient to respiration, and by its counter efforts gradually prevents the quick breathing, and diminishes the associations of the pulmonary vessels with the cutaneous ones. And thus though the same quantity of heat is subducted from the skin, yet the torpor of the pulmonary vessels and internal glands does not follow. Hence during cold immersion less sensorial power is accumulated, and in consequence, less exertion of it succeeds on emerging from the bath. Whence such people are esteemed hardy, and bear the common variations of atmospheric temperature without inconvenience. See Sect. XXXII. 3. 2. IV. Venesection has a just title to be classed amongst the torpentia in cases of fever with arterial strength, known by the fulness and hardness of the pulse. In these cases the heat becomes less by its use, and all exuberant secretions, as of bile or sweat, are diminished, and room is made in the blood-vessels for the absorption of mild fluids; and hence the absorption also of new vessels, or extravasated fluids, the produce of inflammation, is promoted. Hence venesection is properly classed amongst the sorbentia, as like other evacuations it promotes general absorption, restrains hæmorrhages, and cures those pains, which originate from the too great action of the secerning vessels, or from the torpor of the absorbents. I have more than once been witness to the sudden removal of nervous head-achs by venesection, though the patient was already exhausted, pale, and feeble; and to its great use in convulsions and madness, whether the patient was strong or weak; which diseases are the consequence of nervous pains; and to its stopping long debilitating hæmorrhages from the uterus, when other means had been in vain essayed. In inflammatory pains, and inflammatory hæmorrhages, every one justly applies to it, as the certain and only cure. V. When the circulation is carried on too violently, as in inflammatory fevers, those medicines, which invert the motions of some parts of the system, retard the motions of some other parts, which are associated with them. Hence small doses of emetic tartar, and ipecacuanha, and large doses of nitre, by producing nausea debilitate and lessen the energy of the circulation, and are thence useful in inflammatory diseases. It must be added, that if nitre be swallowed in powder, or soon after it is dissolved, it contributes to lessen the circulation by the cold it generates, like ice-water, or the external application of cold air. VI. The respiration of air mixed with a greater proportion of azote than is found in the common atmosphere, or of air mixed with hydrogen, or with carbonic acid gas, so that the quantity of oxygen might be less than usual, would probably act in cases of inflammation with great advantage. In consumptions this might be most conveniently and effectually applied, if a phthisical patient could reside day and night in a porter or ale brewery, where great quantities of those liquors were perpetually fermenting in vats or open barrels; or in some great manufactory of wines from raisins or from sugar. Externally the application of carbonic acid gas to cancers and other ulcers instead of atmospheric air may prevent their enlargement, by preventing the union of oxygen with matter, and thus producing a new contagious animal acid. III. CATALOGUE OF TORPENTIA. 1. Venesection. Arteriotomy. 2. Cold water, cold air, respiration of air with less oxygen. 3. Vegetable mucilages. a. Seeds.--Barley, oats, rice, young peas, flax, cucumber, melon, &c. b. Gums.--Arabic, Tragacanth, Senegal, of cherry-trees. c. Roots.--Turnip, potatoe, althea, orchis, snow-drop. d. Herbs.--Spinach, brocoli, mercury. 4. Vegetable acids, lemon, orange, currants, gooseberries, apples, grape, &c. &c. 5. Animal mucus, hartshorn jelly, veal broth, chicken water, oil? fat? cream? 6. Mineral acids, of vitriol, nitre, sea-salt. 7. Silence, darkness. 8. Invertentia in small doses, nitre, emetic tartar, ipecacuanha given so as to induce nausea. 9. Antacids.--Soap, tin, alcalies, earths. 10. Medicines preventative of fermentation, acid of vitriol. 11. Anthelmintics.--Indian pink, tin, iron, cowhage, amalgama, smoak of tobacco. 12. Lithonthriptics, lixiv. saponarium, aqua calcis, fixable air. 13. Externally, warm bath, and poultices, oil, fat, wax, plasters, oiled silk, carbonic acid gas on cancers, and other ulcers. * * * * * ADDENDA. _Page 625, line 1, after 'number' please to add_, 'except when the patient has naturally a pulse slower than usual in his healthy state.' _Page 197, after line 8, please to add_, 'Where the difficulty of breathing is very urgent in the croup, bronchotomy is recommended by Mr. Field.' Memoir of a Medical Society, London, 1773, Vol. IV. * * * * * ADDITION. * * * * * INABILITY TO EMPTY THE BLADDER. To be introduced at the end of Class III. 2. 1. 6. on Paralysis Vesicæ Urinariæ. An inability to empty the bladder frequently occurs to elderly men, and is often fatal. This sometimes arises from their having too long been restrained from making water from accidental confinement in public society, or otherwise; whence the bladder has become so far distended as to become paralytic; and not only this, but the neck of the bladder has become contracted so as to resist the introduction of the catheter. In this deplorable case it has frequently happened, that the forcible efforts to introduce the catheter have perforated the urethra; and the instrument has been supposed to pass into the bladder when it has only passed into the cellular membrane along the side of it; of which I believe I have seen two or three instances; and afterwards the part has become so much inflamed as to render the introduction of the catheter into the bladder impracticable. In this situation the patients are in imminent danger, and some have advised a trocar to be introduced into the bladder from the rectum; which I believe is generally followed by an incurable ulcer. One patient, whom I saw in this situation, began to make a spoonful of water after six or seven days, and gradually in a few days emptied his bladder to about half its size, and recovered; but I believe he never afterwards was able completely to evacuate it. In this situation I lately advised about two pounds of crude quicksilver to be poured down a glass tube, which was part of a barometer tube, drawn less at one end, and about two feet long, into the urethra, as the patient lay on his back; which I had previously performed upon a horse; this easily passed, as was supposed, into the bladder; on standing erect it did not return, but on kneeling down, and lying horizontally on his hands, the mercury readily returned; and on this account it was believed to have passed into the bladder, as it so easily returned, when the neck of the bladder was lower than the fundus of it. But nevertheless as no urine followed the mercury, though the bladder was violently distended, I was led to believe, that the urethra had been perforated by the previous efforts to introduce a catheter and bougee; and that the mercury had passed on the outside of the bladder into the cellular membrane. As the urethra is so liable to be perforated by the forcible efforts to introduce the catheter, when the bladder is violently distended in this deplorable disease, I should strongly recommend the injection of a pound or two of crude mercury into the urethra to open by its weight the neck of the bladder previous to any violent or very frequent essays with a catheter whether of metal or of elastic resin. * * * * * LINES TO BE PLACED AT THE END OF ZOONOMIA. _BY A FRIEND._ * * * * * _JAMQUE OPUS EXEGI._ * * * * * The work is done!--nor Folly's active rage, Nor Envy's self, shall blot the golden page; Time shall admire, his mellowing touch employ, And mend the immortal tablet, not destroy. * * * * * INDEX OF THE ARTICLES. A. Absorption, iv. 2. 1. ---- cutaneous, mucous, cellular, iv. 2. 2. ---- of the veins, iv. 2. 4. ---- of inflamed vessels, iv. 2. 4. 3. ---- of intestines and liver, iv. 2. 5. ---- of venereal ulcers, iv. 2. 7. ---- not increased by cold, iv. 2. 1. ---- increased by opium after evacuation, ii. 2. 1. Acacia, iv. 3. 5. 2. Acids austere, iv. 2. 1. 2. iv. 3. 1. ---- vegetable, sweet, vii. 3. 4. iv. 2. 1. 2. ---- mineral, vii. 3. 6. Acrid plants, iv. 2. 4. Agriculture, i. 2. 3. 7. Agues, three kinds, iv. 2. 3. 2. iv. 2. 5. iv. 2. 6. 8. Air nourishes, i. 2. 5. ---- warm bath of, iv. 2. 3. 8. Alcali vol. iii. 3. 8. Alcohol, ii. 2. 1. v. 2. 4. Almond, bitter, ii. 3. 1. Althæa, iii. 3. 3. 3. Allium, iii. 3. 3. Aloe, iii. 2. 5. iii. 2. 7. iii. 3. 5. 5. vi. 2. 5. Alum, iii. 2. 1. iv. 2. 2. iv. 2. 5. 2. iv. 2. 5. 3. Amalgama in worms, vii. 1. 2. Amomum zinziber, iii. 3. 1. Amber, oil of, vi. 3. 1. 4. Ammoniac gum, vi. 3. 1. iii. 3. 3. ---- salt or spirit, iii. 3. 1. 3. Anasarca, warm bath in, ii. 2. 2. Anchovy, iii. 2. 1. iii. 3. 1. 4. Animal food, i. 2. 1. 1. Antimony prepared, iii. 3. 1. 5. iii. 2. 1. iv. 1. 10. Anthemis nobilis, iv. 3. 3. ---- pyrethum, iii. 3. 2. Anxiety, v. 2. 4. Apium, petroselinum, iii. 3. 4. 4. Apoplexy, iv. 2. 11. Aristolochia serpentaria, iii. 3. 1. Armenian bole, vi. 2. 3. iv. 3. 5. 3. Arsenic in ague, iv. 2. 6. 8. iv. 3. 6. ---- saturated solution of, iv. 2. 6. 8. ---- in itch, iv. 2. 9. ---- how it acts, iv. 2. 6. 9. ---- how to detect it, iv. 2. 6. 10. Artemisia maritima, iv. 3. 3. ---- absynthium, iv. 3. 3. ---- santonicum, iv. 3. 3. Artichoke-leaves, iv. 3. 3. Asa foetida, iii. 3. vi. 3. 1. Asarum Europeum v. 3. 3. Ascarides, vii. 1. 2. iii. 2. 7. Asparagus, iii. 3. 4. 4. Astragalus tragacanth, iii. 3. 3. 3. Atropa belladona, ii. 3. 1. Azote, i. 2. 5. B. Balsams diuretic, iii. 2. 4. Bandages promote absorption, iv. 2. 10. Bark, Peruvian, iv. 2. 2. ---- long used noxious, iv. 2. 11. Barley, iii. 3. 3. 3. Bath, warm, ii. 2. 2. 1. iii. 3. 1. 6. iii. 3. 3. 4. iii. 2. 3. 3. ---- of warm air, iv. 2. 3. 8. ---- of steam, iv. 2. 3. 8. ---- cold, vii. 2. 3. ---- nutritive, i. 2. 6. 1. Benzoin, iii. 3. 3. Bile of animals, iii. 3. 5. 2. ---- dilute state of, iv. 2. 6. Blisters, how they act, iii. 2. 1. 10. ---- cure heart-burn, iii. 2. 1. 10. ---- stop vomiting, vi. 2. 2. ---- produce expectoration, iii. 2. 3. 2. ---- increase perspiration, iii. 2. 1. 10. Blood, transfusion of, i. 2. 6. 3. Bog-bean, iv. 3. 3. Bole armeniæ, iv. 2. 5. 3. Bone-ashes, iv. 2. 5. 3. Bowels, inflammation of, v. 2. 2. 2. Bryony, white, iii. 3. 8. ---- as a blister, iii. 2. 8. Butter, i. 2. 3. 2. Butter-milk, i. 2. 2. 2. C. Cabbage-leaves, vii. 1. 2. Calcareous earth, i. 2. 4. 3. Calomel, iii. 2. 5. vi. 2. 5. ---- in enteritis, v. 2. 2. 2. Camphor, iii. 3. 1. Canella alba, iii. 3. 1. Cantharides, iii. 2. 6. iii. 2. 8. v. 2. 4. vi. 2. 4. Capillary action increased by tobacco, iv. 2. 3. 7. Capsicum, iii. 3. 1. Carbonic acid gas, vii. 2. 6. Cardamomum, iii. 3. 1. Caryophyllus aromat. iii. 3. 1. Cardamine, iv. 3. 4. Cassia sistul, iii. 3. 5. 1. ---- senna, iii. 3. 5. 5. Castor, vi. 2. 1. vi. 3. 1. Cathartics, mild, iii. 2. 5. ---- violent, v. 2. 2. Cerussa in ulcers, iv. 2. 9. iv. 2. 7. Chalk, iv. 2. 5. 3. Chalybeates, iv. 3. 4. 2. Cheese, i. 2. 2. 3. Cherries, black, ii. 2. 1. 8. Chlorosis, iv. 2. 6. 5. Cicuta, ii. 3. 1. Cinchona, iv. 2. 2. Cinnamon, iii. 3. 1. 2. Clay, iv. 2. 5. 3. Cloves, iii. 3. 1. iii. 3. 2. Cnicus acarna, v. 3. 1. Cocculus indicus, ii. 3. 1. Cochlearia armoracia, iii. 3. 8. iv. 3. 4. ---- hortensis, iv. 3. 4. Cold, continued application of, vii. 2. 3. ---- interrupted, vii. 2. 3. iii. 3. 1. 7. ---- excessive, vii. 2. 3. ---- first affects lymphatics, vii. 2. 3. ---- produces rheum from the nose, vii. 2. 3. ---- quick anhelation, vii. 2. 3. ---- increases digestion, vii. 2. 3. Cold-fit easier prevented than removed, ii. 2. 1. Colic from lead, v. 2. 2. 2. Condiments, i. 2. 7. Convolvulus scammonium, v. 3. 2. Convulsions, iv. 2. 8. Cookery, i. 2. 3. 5. Copaiva balsam, iii. 3. 4. 3. Cowhage, iii. 3. 2. Crab-juice, iv. 2. 2. Cream, i. 2. 3. 2. i. 2. 2. 2. Cucumis colocynthis, v. 3. 2. Cynara scolymus, iv. 3. 3. Cynoglossum, ii. 3. 1. D. Dandelion, iv. 3. 4. Datura stramonium, ii. 3. 1. Daucus sylvestris, iii. 3. 4. 4. Delphinium stavisagria, ii. 3. 1. Diabetes, iv. 2. 5. ---- warm bath in, vi. 2. 4. Diaphoretics, iii. 3. 1. iii. 2. 1. 2. ---- best in a morning, iii. 2. 1. 5. Diarrhoea, vi. 2. 3. Digestion injured by cold, iii. 2. 1. ---- increased by cold, vii. 2. 3. Digitalis, iv. 2. 3. 7. v. 2. 1. 2. ---- tincture of, iv. 2. 3. 7. Dragon's blood, iv. 3. 5. 2. Dropsy, iv. 2. 3. 4. iv. 2. 6. 7. E. Ears, eruption behind, iv. 2. 9. 2. Earth of bones, iv. 2. 5. ---- of alum, vi. 2. 4. ---- calcareous, iv. 2. 5. 3. vi. 2. 4. i. 2. 4. 3. Eggs, i. 2. 1. 4. Egg-shells diuretic, iii. 2. 4. Electricity, ii. 2. 2. 2. iv. 2. 9. Emetics, how they act, v. 2. 1. Errhines mild, iii. 2. 9. ---- in hydrocephalus, v. 2. 3. 1. ---- violent, v. 2. 3. ---- in head-ach, v. 2. 3. 1. Erysipelas, iv. 2. 9. Essential oils, ii. 2. 3. Ether, vitriolic, ii. 2. 3. iii. 3. 1. vi. 3. 1. 3. ---- in ascarides, vii. 1. 2. Etiolation, i. 2. 3. 4. Euphorbium, v. 3. 3. Exercise, iii. 3. 1. 6. ii. 2. 6. Eyes inflamed, ii. 2. 2. 2. iv. 2. 4. 3. F. Famine, times of, i. 2. 3. 5. and 6. Fear, v. 2. 4. Feathers, smoke of, vi. 3. 1. 6. Fennel, iii. 3. 4. 4. Ferula asafoetida, iii. 3. 3. Fish, i. 2. 1. 2. i. 2. 1. 5. Flannel shirt, ii. 2. 2. 1. Flesh of animals, i. 2. 1. Fluke-worm, iv. 2. 6. Foxglove, iv. 2. 3. 7. v. 2. 1. v. 2. 4. ---- tincture of, iv. 2. 3. 7. Friction, ii. 2. 6. iii. 3. 1. 6. G. Galanthus nivalis, vii. 3. 3. Galbanum, vi. 3. 1. Gall-stones, iv. 2. 6. Galls of oak, iv. 3. 5. Garlic, iii. 3. 3. Gentiana centaurium, iv. 3. 3. ---- lutea, iv. 3. 3. Ginger, iii. 3. 1. iii. 3. 4. Gonorrhoea, iv. 2. 2. iii. 2. 4. Gout, iv. 2. 11. 2. Guaiacum, iii. 3. 1. Gum arabic, iii. 3. 3. 3. ---- tragacanth, iii. 3. 3. 3. Glycyrrhiza glabra, iii. 3. 3. 3. Gravel, v. 2. 4. 4. H. Hartshorn, spirit and salt of, iii. 3. 3. iii. 3. 1. vi. 3. 1. 4. ---- calcined, iv. 2. 5. vi. 2. 3. Hæmorrhages, iv. 2. 4. 4. iv. 2. 6. 2. Hæmatoxylon campechianum, iv. 3. 5. 2. Hay, infusion of, i. 2. 3. 6. Head-ach, snuff in, v. 2. 3. 1. Heat, ii. 2. 2. 1. See Bath. ---- an universal solvent, vii. 2. 2. Helenium, iii. 3. 3. 2. Herpes, iv. 2. 1. iv. 2. 9. Herrings, red, iii. 3. 1. 4. Honey, iii. 3. 3. 3. iii. 3. 5. 1. Hop in beer, why noxious, iv. 2. 3. 6. iv. 2. 11. 2. Hordeum distichon, iii. 3. 3. 3. Humulus lupulus, iv. 2. 3. iv. 2. 11. Hydrargyrus vitriolatus, v. 2. 3. Hysteric disease, vi. 2. 1. ---- pains, vi. 2. 1. ---- convulsions, vi. 2. 1. I. Jalapium, iii. 3. 5. 5. Japan earth, iv. 3. 5. 2. Jaundice, iv. 2. 6. 3. Ileus, vi. 2. 5. Incitantia, ii. Intermittents. See Agues. Inverted motions, vi. 2. 1. ---- in hysteric disease, vi. 2. 1. ---- of the stomach, vi. 2. 2. ---- intestinal canal, vi. 2. 5. ---- of lymphatics, vi. 2. 3. Inula helenium, iii. 3. 3. 2. Ipecacuanha, v. 2. 1. Iron, rust of, iv. 3. 6. Irritability prevented, iv. 2. 3. 3. Itch, iv. 2. 1. 3. L. Laurus camphora, iii. 3. 1. ---- cinnamomum, iii. 3. 1. ---- sassafras, iii. 3. 1. Lead, iv. 3. 6. ---- colic from, v. 2. 2. 2. ---- sugar of, iv. 2. 9. Leeks, iii. 3. 3. 1. Legs, ulcers of, iv. 2. 10. Lemon-juice, iv. 2. 1. iv. 2. 2. Leontodon taraxacum, iv. 3. 4. Life shortened by great stimulus, i. 1. Lime, i. 2. 4. 3. Liquorice, iii. 3. 3. 3. Liver inflamed, iv. 2. 6. Logwood, iv. 3. 5. 2. Lymphatics, inverted motions of, v. 2. 1. M. Magnesia alba, iii. 3. 5. 3. Malt, i. 2. 3. 5. Manna, iii. 3. 5. Marsh-mallows, iii. 3. 3. 3. Marjoram, iii. 3. 9. Marum, iii. 3. 9. Mastich, iii. 3. 2. iii. 3. 3. Menianthes trifoliata, iv. 3. 3. Menispermum cocculus, ii. 3. 1. Menstruation promoted, iv. 2. 6. 6. ---- repressed, iv. 2. 6. 6. Mercury, iii. 3. 2. vi. 2. 2. ---- preparations of, iv. 3. 7. iv. 2. 7. iv. 2. 9. ---- injected as a clyster, vi. 3. 5. Metallic salts, iv. 2. 6. Milk, i. 2. 2. Mimosa nilotica, iii. 3. 3. 3. ---- catechu, iv. 3. 5. 2. Mint, vi. 3. 1. 3. Mortification, iv. 2. 9. Mucilage, vegetable, vii. 3. 3. Mucus, animal, vii. 3. 5. Mushrooms, i. 2. 1. 2. Musk, vi. 2. 1. vi. 3. 1. Mustard, iv. 3. 4. See Sinapism. N. Nausea in fevers, vii. 2. 5. Neutral salts diuretic, why, iii. 2. 4. ---- increase some coughs, iii. 2. 4. ---- increase heat of urine, iii. 2. 4. Nicotiana tabacum, iii. 3. 9. ii. 3. 1. Nitre, iii. 3. 4. v. 2. 4. Nutmeg, iii. 2. 1. Nutrientia, i. O. Oil of almonds, iii. 3. 5. 4. ---- in cream, i. 2. 3. 2. ---- of amber, vi. 2. 1. ---- expressed externally, iii. 2. 3. ---- essential, ii. 2. 3. iii. 3. 1. 2. Oiled silk, vii. 3. 13. Oleum, animale, vi. 2. 1. vi. 3. 4. ---- ricini, iii. 3. 5. 4. Onions, iii. 3. 3. Opium, ii. 2. 1. 2. iv. 1. 2. ---- in nervous pains, ii. 2. 1. 5. ---- in inflammatory pains, ii. 2. 1. 6. ---- increases all secretions and absorptions, ii. 2. 1. 1. ---- absorption after evacuation, iv. 2. 8. 2. ii. 2. 1. 3. ---- stops sweats, iv. 2. 1. 2. ---- intoxicates, ii. 2. 1. 1. Oranges, their peel, iv. 3. 3. Orchis, vii. 3. 3. Oxygen gas, ii. 2. 4. i. 2. 5. iii. 2. 11. iv. 1. 4. ---- produces and heals ulcers, iv. 2. 7. P. Papin's digester, i. 2. 3. 5. Papaver somniferum, ii. 3. 1. iv. 3. 2. See Opium. Pains, periodic, cured by opium, ii. 2. 1. Pareira brava, iii. 3. 4. 4. Parsley, iii. 3. 4. Passions, ii. 2. 5. Pasturage, i. 2. 3. 7. Pepper, iii. 3. 1. Peripneumony, iv. 2. 8. 2. Perspiration in a morning, iii. 2. 1. ---- not an excrement, iii. 2. 1. Peru, balsam of, iii. 3. 5. 4. Petechiæ, iv. 2. 4. 2. Pimento, iii. 3. 1. Piper indicum, iii. 3. 1. Pistacia lentiscus, iii. 3. 2. Pix liquida, iii. 3. 3. Plaster-bandage, iv. 2. 10. Pleurisy, iv. 2. 8. 2. Polygala seneka, iii. 3. 3. 2. Poppy. See Papaver. Portland's powder noxious, why, iv. 2. 11. 2. Potatoe-bread, i. 2. 3. 4. Potentilla, iv. 3. 5. Prunes, iii. 3. 5. 1. Prunus domestica, iii. 3. 5. 1. ---- spinosa, iv. 3. 1. ---- lauro-cerasus, ii. 3. 1. Pulegium, vi. 3. 1. 3. Pulse, intermittent, relieved by arsenic, iv. 2. 6. Pyrethrum, iii. 3. 2. Pyrus malus, vii. ---- cydonia, iv. 3. 1. Q. Quassia, iv. 2. 2. Quince, iv. 3. 1. Quinquefolium, iv. 3. 5. R. Ratafie, why destructive, ii. 2. 1. Resin diuretic, iii. 2. 4. vi. 2. 4. Rhamnus catharticus, v. 3. 2. Rheumatism, iv. 2. 4. 5. iv. 2. 10. 2. Rheum palmatum. See Rhubarb. Rhubarb, iii. 2. 1. iv. 2. 5. 1. iii. 3. 5. 5. ---- causes constipation, why, iii. 2. 1. 1. Rice, vii. Roses, iv. 3. 5. Rot in sheep, iv. 2. 6. S. Sago, vii. 3. Sagopænum, vi. 3. 1. Salivation not necessary, iv. 2. 7. ---- hysteric, v. 2. 3. Salt, common, unwholesome, iii. 1. 12. ---- muriatic, iii. 3. 1. ---- in clysters, iii. 2. 7. Salts, why diuretic, iii. 2. 4. ---- neutral, iii. 3. 5. 3. iii. 2. 4. ---- improper in coughs and gonorrhoea, iii. 2. 4. Salt fish and salt meat increase perspiration, iii. 2. 1. Sassafras, iii. 3. 1. Scammony, v. 2. 2. Scarcity, times of, i. 2. 3. 5. and 6. Scilla maritima, v. 2. 2. iv. 2. 3. iii. 3. 3. v. 2. 3. Scorbutic legs, iv. 2. 10. Scrophulous tumours, ii. 2. 4. iv. 2. 9. Sea-water, iii. 3. 5. 3. Secernentia, iii. Secretion of the bladder, iii. 2. 6. ---- of the rectum, iii. 2. 7. ---- of the skin, iii. 2. 8. Seneka, iii. 3. 3. 2. Senna, iii. 3. 5. 5. Serpentaria virginiana, iii. 3. 1. Sialagogues, iii. 2. 2. v. 2. 3. Simarouba, iv. 3. 5. Sinapi, iv. 3. 4. Sinapisms, vi. 2. 2. iii. 2. 8. vi. 2. 2. Sisymbrium nasturtium, iv. 3. 4. Sloes, iv. 2. 2. Snuffs of candles, vi. 3. 1. 4. Society, i. 2. 3. 7. Soot, vi. 3. 1. 4. Sorbentia, various kinds, iv. 2. 1. Spasmodic doctrine exploded, vii. 2. 3. Spermaceti, iii. 3. 3. 3. Spice noxious, iii. 1. 12. Spirit of wine noxious, ii. 2. 1. Sponge, burnt, vi. 3. 1. 4. Squill. See Scilla. Starch, i. 2. 3. 1. ---- from poisonous roots, i. 2. 3. 4. Steam, bath of, iv. 2. 3. 8. Steel, iv. 2. 6. ---- forwards and represses menstruation, iv. 2. 6. Stizolobium siliqua hirsuta, iii. 3. 2. vii. 3. 11. Strychnos nux vomica, ii. 3. 1. Sublimate of mercury, iv. 2. 7. iv. 2. 9. Sugar nourishing, i. 2. 3. 1. and 5. iii. 3. 3. 3. ---- formed after the death of the plant, i. 2. 3. 5. ---- aperient, iii. 3. 5. 1. Sulphur, iii. 3. 5. 4. Sweats in a morning, iii. 2. 1. 5. ---- on waking, iii. 2. 1. 5. ---- cold, v. 2. 5. ---- stopped by opium, iv. 2. 1. 2. T. Tænia, vermes. See Worms. Tamarinds, iii. 3. 5. 1. Tansey, tanacetum, iv. 3. 3. Tar, iii. 3. 3. Tartar, crystals of, iii. 3. 5. 1. Class i. 2. 3. 13. ---- vitriolate, iii. 3. 5. 3. ---- emetic, v. 2. 1. v. 2. 2. Tea, vii. 2. 1. Tears, iii. 2. 10. Testaceous powders, iv. 2. 1. Tetradynamia, plants of, iv. 2. 4. Tincture of digitalis, iv. 2. Tinea, herpes, iv. 2. 1. 4. Tobacco, ii. 3. 1. iii. 3. 9. iv. 2. 3. 7. ---- injures digestion, iii. 2. 2. 3. Tolu balsam, iii. 3. 3. Tormentilla erecta, iv. 3. 5. Torpentia, vii. Tragacanth gum, iii. 3. 3. 3. Turpentine, vi. 2. 4. ---- spirit of, iii. 2. 6. Turpeth mineral, v. 2. 3. Tussilago farfara, iii. 3. 3. 3. U. Ulcers, scrophulous, iv. 2. 9. ---- of the mouth, iv. 2. 2. ---- cured by absorption, ii. 2. 1. 4. iv. 2. 3. 5. Uva ursi, iv. 3. 5. V. Valerian, vi. 3. 1. Vegetable acids, iv. 2. 1. ---- food, i. 2. 1. 2. Venereal ulcers, iv. 2. 7. Venesection, vii. 2. 4. iv. 2. 8. ---- diminishes secretions, vii. 2. 4. ---- increases absorptions, vii. 2. 4. Veratrum, v. 3. 2. Vibices, iv. 2. 4. 3. Vinegar, iv. 2. 1. 2. iv. 2. 4. 3. ii. 2. 1. 9. Vitriol blue in agues, iv. 2. 6. iv. 2. 2. ---- in ulcers, iv. 2. 9. ---- white, iv. 3. 6. v. 2. 1. ---- acid of, iv. 2. 1. ---- in sweats, iv. 1. 1. ---- in small-pox, iv. 1. 1. Volatile salt, vi. 3. 1. 6. Vomiting, v. 2. 2. Vomiting stopped by mercury, vi. 2. 2. Vomits, iv. 2. 3. 7. W. Warm bath, ii. 2. 2. 1. ---- in diabetes vi. 2. 4. Water, i. 2. 4. ---- dilutes and lubricates, vii. 2. 2. ---- cold, produces sweats, iii. 2. 1. ---- iced, in ileus, vi. 2. 5. ---- cresses, iv. 3. 4. Whey of milk, iii. 3. 5. 2. i. 2. 2. 2. Wine, ii. 3. 1. Worms, vii. 1. 2. iii. 2. 7. iv. 2. 6. 4. ---- in sheep, iv. 2. 6. 4. Z. Zinc, vitriol of, v. 3. 1. THE END. * * * * * Corrections made to printed original. Species list for I. 2. 5.: "Tactus imminutus.": 'Tactu, imminutus' in original (compare main text). I. 1. 4. 1. "Nictitatio irritativa": 'Nectitatio' in original (compare contents list). I. 1. 5. 8. "Perpetual sneezings in the measles": 'sneeezings' in original. I. 2. 1. 11. "the periodical venereal orgasm of the female quadrupeds": 'quadupeds' in original. I. 2. 3. 1. "Mucus faucium frigidus": 'fancium' in original (compare contents list). I. 3. 1. 1. "the retrograde motions of the oesophagus": 'retograde' in original. Genus list for II. 3. Original reads 1. Of the arterial system. 2. Of the absorbent system. 3. Of the excretory ducts. - the first two genera do not appear in the species lists or the main text, with "Of the excretory ducts." appearing there as 1. Species list for II. 1. 3.: "Peripneumonia superficialis": 'superficialie' in original (compare main text). Species list for II. 1. 4.: "11. Fistula urethræ." Entry missing in original and subsequent entries wrongly numbered. Species list for II. 1. 6.: "Febris a pure clauso.": 'clanso' in original (compare main text). Species list for II. 1. 7.: "Rubor jucunditatis": 'jucunditalis' in original (compare main text). II. 1. 3. 5. "Raucedo catarrhalis.": 'Rancedo' in original. II. 1. 4. 11. "The perpetual use of bougies, either of catgut or of caoutchouc": 'coartchouc' in original. The same error occurs in III. 1. 1. 15. II. 1. 5. 6. "Psora": 'Psory' in original (compare contents list & index). Species list for III. 1. 2.: "Superstitious hope": 'Supestitious' in original (compare main text). III. 1. 1. 9. "Assafoetida": 'Assafætida' in original. III. 1. 2. 12. "Pulchritudinis desiderium.": 'Pulchitudinis' in original (compare contents list). III. 1. 2. 12. "a medical person in good circumstances": 'cir-circumstances' over line break in original. III. 1. 2. 24. "See Botanic Garden, P. I. Cant. I. l. 278.": 'Botannic' in original. Species list for IV. 2. 2. "Dolor humeri in hepatitide": 'hepatidide' in original. So in text IV. 2. 2. 9.: in index 'hepatidite'. IV. 2. 1. 4. "the capillaries of the stomach and the cutaneous ones": 'cataneous' in original. SUPPLEMENT TO CLASS IV. XII. 11. Ninthly. "the sensorial power of irritation": 'iritation' in original. ibid. "the vertigo eases for a few minutes.": 'cases' (for 'eases') in original. XIII. "once rather delirious": 'delious' in original. XVI. 7. 8. "The urine is pale and in small quantity": 'quanity' in original. INDEX TO CLASSES: "Fever puerperal": 'perpetual' in original. "Suggestion, slow," gives no section number & does not seem to exist. ARTICLES OF THE MATERIA MEDICA: II. 2. 1. 5. "epilepsia dolorifica": 'dolorofica' in original. II. 3. 1. "Strychnos nux vomica": 'nuc' in original. VI. 2. 4. "The diabætes consists": 'diaboetes' in original. V. 3. 3. "hydrargyrus": 'hydragyrus' in original. VII. 2. Article "II." was numbered 'II. 2.', and "III. 1." was numbered 'III. 3. 1.'. Corrected cross references. In SECTION Printed reference Corrected to I. 1. 2. 3. Art. III. 2. 12. (no correction) I. 1. 5. 8. Class II. 1. 1. 2. II. 1. 1. 3. I. 2. 1. 2. Class IV. 1. 2. 6. IV. 2. 1. 16. I. 2. 2. 2. Class II. 3. 1. 1. (no correction) (see Genus list for II. 3.) I. 2. 3. 11. Class I. 2. 3. 16. I. 2. 3. 17. I. 2. 4. 11 Class IV. 1. 2. 11. IV. 2. 2. 7. (first) ibid. Class IV. 2. 1. 7. IV. 2. 2. 7. (second) I. 2. 4. 15. Class II. 1. 2. 13. II. 1. 2. 18. I. 2. 5. 1. Class I. 2. 3. 26. (no correction) ibid. Class I. 2. 3. 25. (no correction) I. 3. 1. 3. Class II. 1. 4. 7. II. 1. 4. 6. I. 3. 1. 5. Class III. 1. 1. 15. III. 1. 1. 14. I. 3. 1. 7. Class I. 3. 1. 9. I. 3. 1. 10. I. 3. 1. 11. Class IV. 2. 1. 7. IV. 1. 2. 7. II. 1. 2. 2. Class II. 1. 5. 3. II. 1. 4. 1. II. 1. 2. 12. Class II. 1. 4. 11. II. 1. 4. 12. II. 1. 3. 3. Class II. 2. 2. 1. (no correction) ibid. Class II. 1. 2. 1. II. 1. 3. 1. II. 1. 3. 17. Class I. 2. 1. 14. I. 2. 1. 15. ibid. Class IV. 2. 1. 16. IV. 1. 2. 16. II. 1. 4. 5. Class II. 1. 5. 1. II. 1. 5. 2. II. 1. 4. 8. Class II. 1. 4. 10. (no correction) II. 1. 4. 17. Class I. 2. 2. 12. I. 2. 2. 14. II. 1. 6. 8. Class II. 1. 4. 12. II. 1. 4. 13. II. 1. 7. 1. Class I. 1. 5. 12. I. 1. 5. 11. II. 2. 2. 1. Class I. 1. 4. 4. I. 2. 4. 12. III. 1. 1. 5. Class IV. 3. 2. 2. IV. 1. 3. 2. III. 1. 2. Sect. XXXV. 1. 13. XXXV. 1. 3. III. 1. 2. 2. Class I. 1. 1. 9. III. 1. 1. 9. III. 1. 2. 10. Class IV. 2. 1. 9. (no correction) III. 1. 2. 14. Class I. 2. 3. 9. I. 2. 4. 10. III. 2. 1. 2. Class IV. 3. 2. 2. IV. 1. 3. 2. III. 2. 1. 4. Class IV. 2. 2. 10. IV. 1. 2. 10. IV. 1. 1. C. Class IV. 1. 4. 6 IV. 1. 4. 5. (2nd time.) In INDEX OF CLASSES: Ascarides iv. 2. 1. 9. iv. 1. 2. 9. Azote i. 11. 4. i. 11. 6. Calculi renis iv. 2. 3. 3. (no correction) Catamenia i. 2. 1. 10. i. 2. 1. 11. Consternation i. 1. 5. 12. i. 1. 5. 11. Constipation ii. 2. 1. 7. ii. 2. 2. 7. Costiveness ii. 2. 1. 7. ii. 2. 2. 7. Diarrhoea rheumatic iv. 2. 1. 16. iv. 1. 2. 16. Digestion decreased ... iv. 1. 2. 5 iv. 2. 1. 6. Dilirium in parotitis iv. 2. 1. 19 iv. 1. 2. 19. Dyspnoea rheumatica iv. 2. 1. 16. iv. 1. 2. 16. Eruption of small-pox iv. 2. 1. 12. iv. 1. 2. 12. Fear, abortion from iv. 1. 3. 7. iv. 3. 1. 7. ---- paleness in iv. 1. 3. 5. iv. 3. 1. 5. Fever sensitive ii. 1. 5. 1. ii. 1. 6. 1. ---- return of cold fit Suppl. i. 3. Suppl. i. 4. Frigus chronicum i. 2. 2. 2. i. 2. 2. 1. Gangreen ii. 1. 6. 17. (no correction) Hoarseness iii. 2. 1. 4. iii. 2. 1. 5. Hydatides in calves i. 2. 5. 2. i. 2. 5. 4. Hydrogene gas i. 11. 4. i. 11. 6. Hysteria from cold iv. 3. 3. 3. iv. 3. 4. 3. Inflammation ... bowels ii. 1. 2. 3. ii. 1. 2. 11. Lingua arida iv. 2. 4. 11. (no correction) Lochia nimia i. 2. i. 2. 1. 13. Lues venerea ii. 1. 5. 8. ii. 1. 5. 2. Maculæ vultus i. 2. 1. 9. i. 2. 2. 10. Mammarum tumor iv. 2. 1. 19. iv. 1. 2. 19. Mammularum tensio iv. 2. 1. 6. iv. 1. 2. 6. Mercury in vertigo iv. 1. 2. 11. iv. 2. 1. 11. Nipples, tension of iv. 2. 1. 6. iv. 1. 2. 6. Paresis sensitiva i. 2. 1. 3. ii. 2. 1. 3. Pubis and throat ... iv. 2. 1. 7. iv. 1. 2. 7. Respiration quick ... ii. 1. 1. 3. ii. 1. 1. 4. Setons ii. 1. 6. ii. 1. 6. 6. Sickness cured by warm iv. 1. 2. 2. iv. 1. 1. 2. Splenitis ii. 2. 2. 13. ii. 1. 2. 13. Sternutatio a lumine iv. 2. 1. 2. iv. 1. 2. 2. Stocks for children ii. 2. 2. 17. i. 2. 2. 17. Surprise i. 1. 5. 12. i. 1. 5. 11. Sympathy throat & pubis iv. 2. 1. 7. iv. 1. 2. 7. Tears sympathetic iii. 1. 1. 10. iii. 1. 2. 10. Tinnitus aurium iv. 1. 1. 15. iv. 2. 1. 15. Torpor of the liver i. 1. 2. 6. i. 2. 2. 6. Tremor of anger iv. 3. 1. 4 iv. 2. 3. 4. ---- of fear iv. 1. 2. 5. iv. 3. 1. 5. Tussis hepatica iv. 1. 2. 7. iv. 2. 1. 8. ---- arthritica iv. 1. 2. 8. iv. 2. 1. 9. ---- periodica iv. 1. 2. 9. iv. 3. 4. 2. ---- a pedibus frigidis iv. 1. 2. 6. iv. 2. 1. 7. Ulcers of the legs ii. 1. 4. 13. ii. 1. 4. 14. Variola eruption of iv. 2. 1. 12. iv. 1. 2. 12. Vertigo with vomiting iv. 2. 3. 2. iv. 3. 2. 3. Watchfulness iv. 3. 2. 5. iv. 1. 3. 6. Winking iv. 3. 2. 2. iv. 1. 3. 2. Womb, inflammation of ii. 1. 8. 16. ii. 1. 2. 16. In ARTICLES OF THE MATERIA MEDICA: II. 2. 1. 5. Class III. 1. 1. 12. III. 1. 1. 13. IV. 2. 3. 8. Class IV. 2. 2. 1. Art. II. 2. 2. 1. IV. 2. 6. 5. Sect. XXX. 4. XXX. 1. 4. V. 2. 1. 4. Art. II. 3. 7. IV. 2. 3. 7. VI. 2. 2. Class IV. 1. 1. 3. IV. 1. 1. 2. INDEX OF THE ARTICLES Acacia iv. 2. 5. 2. iv. 3. 5. 2. Alcali vol. iii. 3. 3. iii. 3. 8. Althæa iii. 2. 3. 3. iii. 3. 3. 3. Aloe iii. 2. 5. 5. iii. 3. 5. 5. Alum iv. 2. 1. iv. 2. 2. Amalgama in worms vii. 2. 2. vii. 1. 2. Amber, oil of vi. 3. 4. vi. 3. 1. 4. Ammoniac salt iii. 3. 3. iii. 3. 1. 3. Anchovy iii. 2. 1. 4. iii. 3. 1. 4. Antimony prepared iii. 2. 1. 5. iii. 3. 1. 5. Apium, petroselinum iii. 2. 4. 4. iii. 3. 4. 4. Armenian bole vi. 3. 5. 3. iv. 3. 5. 3. Asa foetida ii. 3. iii. 3. Ascarides iii. 2. 9. 7. iii. 2. 7. Asparagus iii. 2. 4. 4. iii. 3. 4. 4. Astragalus tragacanth iii. 2. 3. 3. iii. 3. 3. 3. Barley iii. 2. 3. 3. iii. 3. 3. 3. Bath, warm iii. 2. 1. 6. iii. 3. 1. 6. ibid. iii. 2. 3. 4. iii. 3. 3. 4. Bile of animals iii. 2. 5. 2. iii. 3. 5. 2. Blood, transfusion of i. 2. 6. 2. i. 2. 6. 3. Bryony as a blister iii. 2. 9. iii. 2. 8. Cassia sistul iii. 2. 5. 1. iii. 3. 5. 1. ---- senna iii. 2. 5. 5. iii. 3. 5. 5. Chalybeates iv. 2. 4. 2. iv. 3. 4. 2. Cinnamon iii. 3. 2. iii. 3. 1. 2. Cold, interrupted iii. 2. 1. 7. iii. 3. 1. 7. Copaiva balsam iii. 2. 4. 3. iii. 3. 4. 3. Daucus sylvestris iii. 2. 4. 4. iii. 3. 4. 4. Dragon's blood iv. 2. 5. 2. iv. 3. 5. 2. Ether, vitriolic vi. 3. 3. vi. 3. 1. 3. Exercise iii. 2. 1. 6. iii. 3. 1. 6. Eyes inflamed iv. 2. 3. iv. 2. 4. 3. Feathers, smoke of vi. 3. 6. vi. 3. 1. 6. Fennel iii. 2. 4. 4. iii. 3. 4. 4. Friction ii. 2. 5. ii. 2. 6. ibid. iii. 2. 1. 6. iii. 3. 1. 6. Ginger iii. 3. 4. (no correction) Gum arabic iii. 2. 3. 3. iii. 3. 3. 3. ---- tragacanth iii. 2. 3. 3. iii. 3. 3. 3. Glycyrrhiza glabra iii. 2. 3. 3. iii. 3. 3. 3. Hæmatoxylon camp... iv. 2. 5. 2. iv. 3. 5. 2. Hartshorn, spirit ... iii. 3. 3. (no correction) ibid. vi. 3. 4. vi. 3. 1. 4. Helenium iii. 2. 3. 2. iii. 3. 3. 2. Herrings, red iii. 2. 1. 4. iii. 3. 1. 4. Honey iii. 2. 3. 3. iii. 3. 3. 3. ibid. iii. 2. 5. 1. iii. 3. 5. 1. Hordeum distichon iii. 2. 3. 3. iii. 3. 3. 3. Jalapium iii. 2. 5. 5. iii. 3. 5. 5. Japan earth iv. 2. 5. 2. iv. 3. 5. 2. Inula helenium iii. 2. 3. 2. iii. 3. 3. 2. Leeks iii. 2. 3. 1. iii. 3. 3. 1. Liquorice iii. 2. 3. 3 iii. 3. 3. 3. Logwood iii. 2. 5. 2. iv. 3. 5. 2. Magnesia alba iii. 2. 5. 3. iii. 3. 5. 3. Marsh-mallows iii. 2. 3. 3. iii. 3. 3. 3. Mastich iii. 3. 3. (no correction) Mimosa nilotica iii. 2. 3. 3. iii. 3. 3. 3. ---- catechu iv. 2. 5. 2. iv. 3. 5. 2. Mint vi. 3. 3. vi. 3. 1. 3. Oil essential iii. 3. 2. iii. 3. 1. 2. Oleum, ricini iii. 2. 5. 4. iii. 3. 5. 4. Pareira brava iii. 2. 4. 4. iii. 3. 4. 4. Peru, balsam of iii. 2. 5. 4. iii. 3. 5. 4. Pix liquida iii. 3. 2. iii. 3. 3. Prunes iii. 2. 5. 1. iii. 3. 5. 1. Prunus domestica iii. 2. 5. 1. iii. 3. 5. 1. Pulegium vi. 3. 3. vi. 3. 1. 3. Rhubarb iii. 2. 5. 5. iii. 3. 5. 5. Salts, neutral iii. 2. 5. 3. iii. 3. 5. 3. Sea-water iii. 2. 5. 3. iii. 3. 5. 3. Seneka iii. 2. 3. 2. iii. 3. 3. 2. Senna iii. 2. 5. 5. iii. 3. 5. 5. Snuffs of candles vi. 3. 4. vi. 3. 1. 4. Soot vi. 3. 4. vi. 3. 1. 4. Spermaceti iii. 2. 3. 3. iii. 3. 3. 3. Sponge, burnt vi. 3. 4. vi. 3. 1. 4. Sugar nourishing iii. 2. 4. 3. iii. 3. 3. 3. ---- aperient iii. 2. 5. 1. iii. 3. 5. 1. Sulphur iii. 2. 5. 4. iii. 3. 5. 4. Sweats in a morning iii. 2. 1. 1. iii. 2. 1. 5. ---- on waking iii. 2. 1. 1. iii. 2. 1. 5. Tamarinds iii. 2. 5. 1. iii. 3. 5. 1. Tartar, crystals of iii. 2. 5. 1. iii. 3. 5. 1. ---- vitriolate iii. 2. 5. 3. iii. 3. 5. 3. Testaceous powders iv. 2. 2. iv. 2. 1. Tobacco iv. 2. 3. 8. iv. 2. 3. 7. Tragacanth gum iii. 2. 3. 3. iii. 3. 3. 3. Tussilago farfara iii. 2. 3. 3. iii. 3. 3. 3. Valerian vi. 3. 3. vi. 3. 1. Vinegar iv. 2. 1. 9. iv. 2. 1. 2. Volatile salt vi. 3. 6. vi. 3. 1. 6. Whey of milk iii. 2. 5. 2. iii. 3. 5. 2.